Physical & Chemical Characterization of emissions from 2 ......mopeds, completely change the...

EUR 23999 EN - 2009

Physical & Chemical Characterization ofemissions from 2-Stroke motorcycles

G. Martini, C. Astorga, T. Adam, P. Bonnel, A. Farfaletti, H. Junninen, U. Manfredi,L. Montero, A. Müller, A. Krasenbrink, B. Larsen, M. Rey and G. De Santi.

Comparison with 4-stroke engines

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The mission of the Institute for Environment and Sustainability is to provide scientific-technical support to the European Union’s Policies for the protection and sustainable development of the European and global environment. European Commission Joint Research Centre Institute for Environment and Sustainability Contact information: G. Martini, M.C. Astorga-Llorens Address: Transport & Air Quality Unit, TP.441; Via E. Fermi, 2749- 21027 Ispra E-mail: [email protected]; [email protected] Tel.: + 39 0332 789293/ 6110 Fax: + 39 0332 785236 http://ies.jrc.ec.europa.eu/ http://www.jrc.ec.europa.eu/ Legal Notice Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use which might be made of this publication.

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A great deal of additional information on the European Union is available on the Internet. It can be accessed through the Europa server http://europa.eu/ JRC 53779 EUR 23999 EN ISBN 978-92-79-13540-8 ISSN 1018-5593 DOI 10.2788/38196 Luxembourg: Office for Official Publications of the European Communities © European Communities, 2009 Reproduction is authorised provided the source is acknowledged Printed in Italy

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Physical & Chemical Characterization of emissions from 2-Stroke Motorcycles

(Comparison with 4-stroke engines)

Study Jointly Performed by: Transport and Air Quality Unit; Institute for Environment and

Sustainability, EC-Joint Research Centre (Ispra, Italy)

Authors: This Report has been prepared by: G. Martini and C. Astorga, T. Adam

with collaborations from:, P. Bonnel, A. Farfaletti, H. Junninen, U. Manfredi, L. Montero, A. Müller, A. Krasenbrink, B.R. Larsen, M. Rey and G. De Santi

Acknowledgements: R. Colombo, M. Duane, G. Lanappe, P. Le Lijour, M. Sculati. This experimental program has been carried out with the essential contribution of CUNA (Commissione Tecnica di Unificazione nell Autoveicolo) and ANCMA (Associazione Nazionale Costruttori Motocicli ed Accessori) in particular our acknowledge to P. Alburno and P. Colombo (Dell'Orto SpA).

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Physical & Chemical Characterization of emissions from 2-Stroke Motorcycles

(Comparison with 4-stroke engines)

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index: Table of Content Abstract; Summary and conclussions 1. INTRODUCTION......................................................................................................................- 15 - 2. ASSESSMENT OF ADVANCED TECHNOLOGIES TO REDUCE EMISSIONS FROM MOPEDS............................................................................................................................................- 18 -

2.1 Legislative frame for mopeds and motorcycles .................................................................- 18 - 2.2 Experimental program........................................................................................................- 20 -

2.2.1 Test Fleet ....................................................................................................................- 20 - 2.2.2 Experimental set up ....................................................................................................- 20 - 2.2.3 Emission tests .............................................................................................................- 20 - 2.2.4 Instrumentation details...............................................................................................- 22 -

2.3 Regulated Emissions, CO2 and PM ...................................................................................- 23 - 2.4 Gaseous Emissions – CO, NOx + HC and CO2.................................................................- 23 -

2.4.1 ECE 47 driving cycle..................................................................................................- 23 - 2.4.2 WMTC driving cycle...................................................................................................- 26 - 2.4.3 Effect of the Electronic Carburetor System (ECS) .....................................................- 28 - 2.4.4 Particulate Emissions.................................................................................................- 30 -

2.5 Correlation of PM vs HC emissions: Topics to be treated in future projects.....................- 32 - 2.6 Unregulated emissions: Chemical composition of particulate and volatile organic fraction of the vehicular exhaust. .....................................................................................................................- 33 -

2.6.1 Chemical analysis of PAH derivatives adsorbed in the exhaust particulate .............- 33 - 2.6.2 PAH clean up and analysis: Experimental details .....................................................- 34 - 2.6.3 PAH concentration in the particulate exhaust from mopeds .....................................- 36 - 2.6.4 Overall potential toxicity of the Mixture: Particulate toxicity from PAHs ................- 39 - 2.6.5 Volatile emissions from mopeds: NMHC & carbonyls ..............................................- 41 - 2.6.6 VOC speciation...........................................................................................................- 41 - 2.6.7 VOCs speciation over ECE 47 and WMTC driving cycles ........................................- 43 - 2.6.8 Ozone formation potential of VOCs ...........................................................................- 48 - 2.6.9 Carbonyl Compounds.................................................................................................- 50 - 2.6.9.1 Sampling & analysis methodology .............................................................................- 51 - 2.6.9.2 Experimental results...................................................................................................- 51 -

2.7 Conclusions ........................................................................................................................- 53 - 3. TWO-STROKE ENGINES VERSUS FOUR-STROKE ENGINES: COMPARISON OF EMISSIONS.......................................................................................................................................- 56 - 4. EFFECT OF LUBRICANT QUALITY AND USE OF GASOEUS FUEL (LPG) ON EXHAUST EMISSIONS FROM MOPEDS .........................................................................................................- 65 -

4.1 Experimental work .............................................................................................................- 65 - 4.1.1 Test fleet .....................................................................................................................- 65 - 4.1.2 Test lubricants ............................................................................................................- 65 - 4.1.3 Test fuel ......................................................................................................................- 65 - 4.1.4 Emission tests .............................................................................................................- 66 -

4.2 Particulate emissions characterisation................................................................................- 66 - 4.3 Instrumentation details .......................................................................................................- 69 - 4.4 Results ................................................................................................................................- 69 -

4.4.1 Effect of lubricant quality...........................................................................................- 69 - 4.4.1.1 Particulate total mass.................................................................................................- 69 - 4.4.1.2 Mass/size distribution.................................................................................................- 71 - 4.4.1.3 Number/size distribution (steady state conditions) ....................................................- 73 - 4.4.2 Effect of lubricant quality on gaseous emissions .......................................................- 76 - 4.4.3 Tests on a moped converted to LGP fuel....................................................................- 78 -

4.5 Conclusions ........................................................................................................................- 80 - 5. REFERENCES...........................................................................................................................- 81 -

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ABSTRACT

Due to the significant emission reduction from light and heavy duty vehicles in the past few years, it came out that two-stroke engines are a considerably strong source of pollution in the urban areas where congested traffic made of these vehicles an appropriate alternative to increase mobility. After the entry into force of additional measures on light-duty vehicles (Euro 5/6) and on heavy duty vehicles (Euro VI), the share of two- and three-wheelers in total emissions should increase, in particular they may become higher contributors to gaseous emissions. In this context, the Commission wishes to prepare a recast of the legislation on the type-approval of two- and three-wheelers as well new measures on safety and pollutant emissions to be proposed by mid 2009. In view of this new legislative process and the preparation of an amendment to the European directives 97/24/EC and 2002/51/EC5 on “characteristics of two or three-wheel motor vehicles”, Transport and Air Quality Unit has worked on the characterization of emissions from motorcycles with the aim of obtaining estimates of the impact of these emission sources on air quality. In this research program, we have taken into consideration some measures that can be adopted to reduce emissions from the existing mopeds, considering that the next stricter emission standards for mopeds will bring important benefits only in the mid/long-term, when a significant fraction of the fleet will have been replaced by newer vehicles. Indeed, new available after-treatment technologies may reduce emissions from Euro 1, two-Stroke motorcycles by a factor of 10 compared to previous emissions standard. Some of these new technologies for emission reduction are still under development and they are expected to be ready to allow new emission limits in the next legislative proposal. This project also showed the influence of the engine technology and running conditions on the emissions for regulated pollutants as well as for some non-regulated ones (ie. PM, CO2, PAHs, VOCs, Carbonyls). Throughout the testing programme on mopeds, engine settings and maintenance resulted to affect emissions to a large extent. This means that an inspection and maintenance programme for mopeds can be very effective in reducing emissions. Anti-tampering measures should put in place in order to prevent people from this practice.

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Summary and conclusions The study described in this report has addressed three main questions regarding two-wheelers:

• How do emissions from two-stroke engines compare with four-stroke engines? • Can advanced technologies reduce emissions from mopeds equipped with two-stroke engines? • Is it possible to reduce emissions from the existing moped fleet?

The JRC has tested six mopeds certified for different emission standards (pre-Euro 1, Euro 1 and Euro 2) and a number of motorcycles equipped with four-stroke engines. All the tests have been carried out at the VELA laboratory of the JRC. The main results can be summarized as follow: - In general, mopeds equipped with two-stroke engines have high emissions of unburnt

hydrocarbons mainly due to the expulsion of fresh mixture during the scavenging phase. In addition, two-stroke engines exhibit significant or very high particulate emissions although the composition is quite different from particulates emitted by diesel engine. While in the latter case a large fraction of particulates consists of carbonaceous material (soot), particulates emitted by two-stroke engines mainly consists of condensed heavy hydrocarbons coming for the incomplete combustion of lubricant. Both HC and PM emission levels vary significantly depending on engine technology. On the other hand, conventional two-stroke engines have very low NOx emissions, much lower than four-stroke engines. Taking into consideration the role played by NOx in secondary aerosol formation, it is clear that simply replacing two-stroke engines with four-stroke engines will result in limited benefits in terms of ambient aerosol and PM reduction. Furthermore, some advanced technologies developed to reduce HC and PM emissions from mopeds, completely change the emission pattern of the two-stroke engines. In particular, the direct injection technology implemented in some models reduces significantly HC emissions but result in a large increase of NOx which reach the typical levels of four-stroke engines. Four-stroke engines can however benefit from the adoption of three way catalysts but it is questionable whether such technology can be as effective as for passenger cars or large motorcycles in the case of low price small mopeds.

- Other advanced technologies like electronic carburetors, oxidation catalysts, etc, can be very

effective in reducing emissions from mopeds. In particular, a moped equipped with an optimized electronic carburetor exhibited regulated emissions at the same level as four-stroke engines. This means that for small mopeds advanced two-stroke engines may represent a viable option in order to reduce their impact on the environment.

- As far as the existing fleet is concerned, the data (year 2006) from ACI (Automobile Club

d’Italia) show that 76% of the motorcycles and mopeds circulating in Regione Lombardia belong to the Euro 0 (53%) and Euro 1 (23%) emission classes. It is clear that stricter emission standards being discussed just now among the Commission and the stakeholders will bring important benefits only in the mid/long-term, when a significant fraction of the fleet will have been replaced by newer vehicles. Nevertheless there are some measures that can be adopted to reduce emissions from the existing mopeds. Throughout the testing programme on mopeds conducted at the JRC, engine settings and maintenance resulted to affect emissions to a large extent. This means that an inspection and maintenance programme for mopeds can be very effective in reducing emissions. In addition, it is well known that most of mopeds are modified in order to remove the speed limiting device and this has a huge effect on emissions. Anti-tampering measures should put in place in order to deter people from this practice.

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Moreover, other tests carried out at the JRC have shown that a high quality lubricant (e.g. full-synthetic) can reduce PM emissions up to 62% and, to a lower extent, gaseous emissions. Finally, other works performed in collaboration with the Swiss network BAFU have found that other aspects are important to control emissions from mopeds:

• Lower oil dosing • Supplementary filtration and oxidation devices (wire-mesh filter catalyst) • Higher quality fuels

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1. INTRODUCTION

During the last 20 years, the approval and implementation of successive stricter regulations on polluting emissions from passenger cars, as well as from heavy-duty vehicles, has marked the technological progress made on these engines and their corresponding post-treatment devices. As a result, pollutant emissions from passenger cars and heavy duty vehicles have been reduced by more than 90%. Nowadays, in some cases, emission levels of regulated pollutants from passenger cars are so low that it is a real challenge to reliably measure them. In this race the development of similar adequate regulations for two-wheelers has been delayed. Such developments are now taking place for motorcycles and mopeds. However still today, the emission standards for two-wheelers are less severe than those already come into force for passenger cars. In the past, two-wheelers have been often considered less pollutant than passenger cars and having a limited impact on air quality. The real impact of motorcycles and in particular of mopeds became evident in the ‘90s when in some urban areas the air quality improvements turned out to be smaller than expected from the introduction of more sever emission standards for LD and HD. In particular, in some big cities the benzene concentration in the air was not decreasing at all despite the lower emissions from passenger cars and the introduction of gasoline containing less than 1% of benzene. Pioneer studies from several research organizations provided the evidence that motorcycles and mopeds represent a significant source of pollutant emissions and that the contribution to air pollution can be very important in those urban areas where busy roads and frequent traffic jams make the two-wheelers very popular.

Two-wheelers are an important source of pollution (CO, PM, HC…) not only in the southern Mediterranean cities in Europe but even more in the Asian countries. Almost 70% of the vehicular fleet in India consists of 2- and 3-wheeler and China produces almost three times the number of vehicles than India. More than 90% of the 2-and 3 wheelers are produced in Asia. But also in Europe we find that two wheelers are very popular in urban areas where congested traffic made of these vehicles an appropriate alternative to increase mobility. We have examples like Regione Lombardia (Italy) where we find more than 800000 motorcycles circulating (Source: ACI, 2006 fleet). About 53% of these motorcycles (see Figure 2.1) are not certified for any emission standards (Euro 0). Only a few (3%) comply with the most recent standards (Euro 3). Nearly 24% of the existing fleet consists of motorcycles equipped with an engine having a displacement below 125 cc. A significant fraction of these vehicles is represented by mopeds having two-stroke engines which, in general, are more polluting than four stroke engines. Small scooters are even more popular and very much used in the congested urban centres resulting in a notable source of air pollution. Nevertheless the need of mobility makes unavoidable the level of transportation in Europe and in some developing countries (like China and India) the tendency is to grow even more [1]. This need for mobility and economical growth has a negative impact on health and the environment (urban air pollution, climate change). That means that if we do want to maintain the level of transport we should go for cleaner technologies.

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Motorcycles In Regione LombardiaDistribution per emission classes

EURO 053%

EURO 123%

EURO 221%

EURO 33%

Total Number: 814231

Figure 1 – Distribution of motorcycles per emission class (source: ACI, 2006 fleet)

Motorcycles in Regione LombardiaEngine size distribution

<125 CC24%

126 - 250 cc25%

251 - 750 cc37%

> 750 cc14%

Total Number: 814231

Figure 2– Distribution of motorcycles per displacement (source: ACI, 2006 fleet)

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Motorcycles in Italy - Distribution per region

0

100000

200000

300000

400000

500000

600000

700000

800000

900000

Abru

zzo

Basil

icata

Cala

bria

Camp

ania

Emilia

Rom

agna

Friul

i Ven

ezia

Giul

iaLa

zioLig

uria

Lom

bard

iaM

arch

eM

olise

Piem

onte

Pugli

aSa

rdeg

naSi

cilia

Tosc

ana

Tren

tino

Alto

Adi

geUm

bria

Valle

D'A

osta

Vene

tono

t asc

ribed

Total: 5,288,818

2.1%

0.5 %

2.1%

9.1%

7.9%

2.0%

10.9 %

6.0 %

15.4 %

3.0 %

0.4 %

1.8 %

9.4 %

8.4 %

1.4 % 1.4 %

0.2 %

6.8 %

0.1 %

6.5 %

4.4 %

Motorcycles in Italy - Distribution per region

0

100000

200000

300000

400000

500000

600000

700000

800000

900000

Abru

zzo

Basil

icata

Cala

bria

Camp

ania

Emilia

Rom

agna

Friul

i Ven

ezia

Giul

iaLa

zioLig

uria

Lom

bard

iaM

arch

eM

olise

Piem

onte

Pugli

aSa

rdeg

naSi

cilia

Tosc

ana

Tren

tino

Alto

Adi

geUm

bria

Valle

D'A

osta

Vene

tono

t asc

ribed

Total: 5,288,818

2.1%

0.5 %

2.1%

9.1%

7.9%

2.0%

10.9 %

6.0 %

15.4 %

3.0 %

0.4 %

1.8 %

9.4 %

8.4 %

1.4 % 1.4 %

0.2 %

6.8 %

0.1 %

6.5 %

4.4 %

Figure 3– Distribution of motorcycles by Region-Italy (source: ACI, 2006 fleet)

By representing the distribution of motorcycles by region we realize that Lombardia is the one with the highest number of motorcycles (814.231, representing 15% of the total). In the capital of this region, Milan, 341.693 motorcycles are registered, being the second city in Italy in total amount of two wheelers only outnumbered by Rome with 458.345 motorcycles circulating. (Source ANCMA, 2006). The JRC-Transport and Air quality Unit has been working on the characterization of emissions by 2-stroke motorcycles with the aim to obtain estimates of the impact of these emission sources on air quality and human exposure. This report presents the results and the conclusions of the experimental activities carried out at the JRC to assess different advanced technologies developed to reduce mainly particulate emissions from new mopeds and possible measures to reduce the emissions from those already circulating on the roads.

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2. ASSESSMENT OF ADVANCED TECHNOLOGIES TO REDUCE EMISSIONS FROM MOPEDS

In previous research programs, several technologies have been found to greatly reduce PM emissions (secondary air system, electronic carburetors, new after-treatment devices, high quality lubricants,…). It was also agreed, at the end of these projects, that further research is necessary to optimize some of these technologies (particularly after-treatment devices) [2]. In the present report, we will show results of the influence of the engine technology and running conditions on the emissions for regulated pollutants as well as for some non-regulated ones (ie. PM CO2, PAHs, VOCs, Carbonyls). The results have been very promising and the scientific output may be of great use for the assessment of future limits for emissions standards of 2 stroke engines (Revision of the European Directive 97/24/EC). The main topic of this project was a global approach for 2-stroke emissions, reduction of particles and volatile organic compounds emitted by mopeds. The drivers for this research are many and they arise from different sides. We mention the most important ones below:

• Search for new technologies which can help to reduce the environmental impact of 2-stroke

motorcycles

• Generation of emissions data as an input for emissions inventories and/or source apportionment

• Scientific support to assess probable new limits for future emission legislation development (Support to European Legislation: Amendment of the European Directive 97/24/EC; EURO3 stage for two stroke mopeds)

All the experimental work related to this project has been carried out at the VELA Facility (Vehicle Emissions Laboratory) of the Transport and Air Quality Unit at the Ispra Site (Italy).

2.1 Legislative frame for mopeds and motorcycles After the entry into force of additional measures on light-duty vehicles (Euro 5/6) and on heavy duty vehicles (Euro VI), the share of two- and three-wheelers in total emissions should increase. Therefore the emissions from these vehicles should also be addressed. Directive 97/24/EC is one of the separate Directives under the type-approval procedure. It introduced Euro 1 (from 1999) and Euro 2 (from 2002) for mopeds and light quadricycles as well as Euro 1 (From 1999) for motorcycles, tricycles and quadricycles. This Directive was amended by Directive 2002/51/EC in order to introduce Euro 2 standards from 2003 for all motorcycles, quadricycles and tricycles and a Euro 3 step from 1 January 2007 for all motorcycles.

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EU Directive 97/24/EC: emission limit values for Mopeds and Motorcycles: Emission limit value for Mopeds CO (g/km) HC + NOx

(g/km) EURO 1 (17-06-1999) (two stroke)

6 3

EURO 2 (17-06-2002) (four stroke)

1 1.2

Test cycle: UN-ECE 47 (Emissions measured for 4 modes, only during the hot phase). Emission limit value for Motorcycles: CO (g/km) HC (g/km) NOx (g/km) EURO 1 (17-06-1999) (two stroke)

8 4 0.1

EURO 1 (17-06-1999) (four stroke)

13 3 0.3

Test cycle: UN-ECE 40 (Emissions measured for 4 modes, only hot phase). No further legislation for mopeds after EURO 2.

Directive 2002/51/EC5 has introduced Euro 3 step from 1 January 2007 for all types of motorcycles. As suggested in this directive, the Commission granted a study to assess a number of possible additional measures concerning two- and three-wheelers EU Directive 2002/51/EC: emission limit values for Motorcycles Emission limit value for Motorcycles (<150 cm3) [1]

CO (g/km) HC (g/km) NOx (g/km)

EURO 2 (2003) 5.5 1.2 0.3 EURO 3 (2006) 2.0 0.8 0.15 [1] Motorcycles Test cycle : UN-ECE 40 (emissions measured for all six modes. Sampling starts at T=0) EU Directive 2002/51/EC: emission limit values for Motorcycles (<150 cm3) Emission limit value for Motorcycles (>150 cm3) [2]

CO (g/km) HC (g/km) NOx (g/km)

EURO 2 (2003) 5.5 1.0 0.3 EURO 3 (2006) 2.0 0.3 0.15 [2] Test cycle : ECE 40 + EUDC (emissions measured for all modes. Sampling star at T=0) Directive 2002/24/EC relating to the type-approval of two- or three-wheel motor vehicles ("two and three-wheelers") and its daughter directives have established a harmonized framework for the European type-approval vehicle of L Category: mopeds, motorcycles, tricycles and quadricycles. This framework became mandatory from 9 may 2003 for all L vehicles sold in the European Union. Directive 2002/24/EC laid down Directive 97/24/EC which is one of the separate Directives under the type-approval procedure. In these circumstances, the Commission is envisaging the preparation of a new piece of legislation on the type-approval of two- and three-wheelers as well new measures on safety and pollutant emissions to be proposed by the end of 2009.

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2.2 Experimental program

2.2.1 Test Fleet The test fleet consisted of three mopeds with different engine technology and coming from different manufactures. One of the mopeds was provided with direct injection system while the others had carburetor technology.

The main data of the vehicles are listed here below (Table 1):

Vehicle Type Moped PT001 Moped YI002 Moped PO003 Emission level EURO 2 EURO 2 EURO 2

Category Moped Moped Moped Displacement (cm3) 50cc 50cc 50cc Combustion Type 2 Stroke 2 Stroke 2 Stroke Injection System Carburetor

with electronic control

Carburetor Direct injection

Oxidation Catalyst Y(yes) N(no)

Y Y Y

2.2.2 Experimental set up The experimental part of the work was carried out at the JRC-VELA1 emissions test facility on a chassis dynamometer (Roller bench 48”) suitable for testing small two wheelers and using a conventional CVS system (dilution tunnel). Regulated emissions (HC, CO, NOx) were measured following the legislative measuring procedures. In addition, also particulate emissions were characterized, both, in terms of total mass and potential toxic compounds. PM was collected on Teflon coated filters after the dilution tunnel and further chemical analyses for PAHs were analyzed by GC-MS (EI ionization mode) after Soxhlet extraction and clean up (SPE). Also speciation and quantification of VOCs was performed by GC-FID. Finally, carbonyl analysis was done by HPLC-UV.

2.2.3 Emission tests

The emission tests were carried out on a chassis dynamometer using the European driving cycle (UN-ECE 47). According to the current version of the legislative procedure for emission measurement, the ECE47 driving cycle for mopeds is split into two phases of equal duration (cold phase and hot phase, see Figure 4). There is no obligation to sample during the first phase of the cycle (cold) while for the second phase (hot) exhaust gas is sent to the bags for analysis. Current Euro 2 emission standards concerning CO and NOx+HC reported in the Directive only fix ceilings for the hot phase of the cycle. However, in the tests performed at the JRC, emissions were measured during the cold phase of the cycle as well. According to the latest discussions between legislative bodies and stakeholders, Member states and Manufarcturers, it came out a new proposal and, in the near future, emissions could be calculated as the weighted average of the values measured over the cold phase (30%) and over the hot phase (70%). Therefore the results of the tests are also presented as weighted average.

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In addition, the proposed worldwide harmonized test cycle was also used: WMTC 50 (Figure 5). In this case two WMTC were carried out in sequence. The first one is referred to as Cold WMTC and the second one as Hot WMTC. Each test was repeated 3 times and the results we show in this report are the average of them.

Cycle ECE47 cold + hot phases max speed 45 km/h

0

5

10

15

20

25

30

35

40

45

50

0 100 200 300 400 500 600 700 800 900 1000

Time of the cycle [s]

Spee

d [k

m/h

]

Figure 4– ECE 47 driving cycle

Cycle WMTC 1+1 max speed 45 km/h

0

5

10

15

20

25

30

35

40

45

50

0 200 400 600 800 1000 1200

Time of the cycle [s]

Spee

d [k

m/h

]

Figure 5 – WMTC 50 cycle

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2.2.4 Instrumentation details Regulated pollutant emissions were measured using a chassis dynamometer and a conventional CVS system with a critical flow Venturi. To follow the legislative cycle, the driver was assisted by a driver aid system. Emission measurements were performed using the following analysers:

• CO: IR analyser. • NOx: Chemiluminescence analyser. • HC: FID analyser. • Particulate mass: particulate samples were collected according to the legislative procedure for

diesel vehicles using Pallflex T60A20 filters and the mass was determined by weighing.

In order to protect the instruments from excessive contamination due to lubricant droplets contain in the exhaust, a cyclone was inserted in the transfer line between the tailpipe and the dilution tunnel.

Vexh

Vair

Vmix

Cyclone

To Vent

Bags(diluted ehxaust)

Bags(Air)

VPM

VLPI

Filter Holder

Low Pressure Impactor (LPI)

Ciclon

Vol air

Volume exhaust

Filters

LPI

Air bags

Dilution

tunnel

(VOCs & Carbonyls)

Vexh

Vair

Vmix

Cyclone

To Vent


Bags(Air)

VPM

VLPI

Filter Holder


Ciclon

Vol air

Volume exhaust

Filters

LPI

Air bags

Dilution

tunnel

(VOCs & Carbonyls)

Vexh

Vair

Vmix

Cyclone

To Vent


Bags(Air)

VPM

VLPI

Filter Holder


Ciclon

Vol air

Volume exhaust

Filters

LPI

Air bags

Dilution

tunnel

(VOCs & Carbonyls)

Figure 6 – Typical layout of the emission test facility.

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2.3 Regulated Emissions, CO2 and PM Previous in-house studies demonstrated that two stroke engines have high particulate emissions, especially if compared to motorcycles equipped with four stroke engines. In terms of mass mopeds may have particulate emissions similar to a diesel vehicle; however the composition and the nature of particulates are very different. In the case of mopeds particulates mainly consist of unburned lubricant oil; more than 90% of the particulate mass consists of volatile organic material.

Particulate Emissions from Mopeds and Motorcycles - Total Mass (Filter)Complete Euro 3 Cycle (6 Urban Driving Cycles)

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0.080

MT001-50 MT002-50 MT003-50 MT004-125 MT005-125 MT006-200 MT007-500Motorcycle

Tota

l Mas

s, (g

/km

)

0.20Moped - 2 strokePre-Euro 1

Moped - 2 strokeOxycat

Moped - 2 strokeDirect Injection

4-stroke Motorcycles

EURO4 Diesel Passenger cars = 0,025 g/km

Figure 7 Total Mass collected in filters for mopeds and motorcycles

2.4 Gaseous Emissions – CO, NOx + HC and CO2

2.4.1 ECE 47 driving cycle The results of the tests carried out with the three mopeds are shown in the Figures 7 to 19. The measured emission levels are reported for the hot part of the ECE driving cycle (4 cycles not including the cold part of the cycles). We have also report the results considering 30% of the cold part and 70% of the hot phase as it has been suggested by legislative bodies and stakeholders, Member states and Manufarcturers for the new legislation of 2 wheelers.

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Hot ECE 47

0.0

0.5

1.0

1.5

2.0

2.5

3.0

YI002 PO003 PTOO1

g / k

m

HC CO HC+NOx

Figure 8 – Gaseous emissions measured over the ECE 47 HOT Phase

ECE 47

0.0

0.5

1.0

1.5

2.0

2.5

3.0

YI002 PO003 PTOO1

g / k

m

HC CO HC+NOx

Figure 9 – Gaseous emissions (weighted average 30/70)

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0.00

0.05

0.10

0.15

0.20

YI002 PO003 PTOO1

g / k

m

NOx ECE 47

0.00

0.05

0.10

0.15

0.20

YI002 PO003 PTOO1

g / k

m

NOx Hot ECE 47

Figure 10 – NOx emissions (weighted average 30/70) and hot phase

0

10

20

30

40

50

60

70

80

90

YI002 PO003 PTOO1

g / k

m

CO2 ECE 47

0

10

20

30

40

50

60

70

80

90

YI002 PO003 PTOO1

g / k

m

CO2

Hot ECE 47

Figure 11– CO2 emissions (weighted average 30/70) and hot phase CO and HC emissions Looking at the results obtained over the hot phase of the cycle, as prescribed by the current legislation, all the mopeds tested comply with the Euro 2 limits (Figure 8 ). However, when the weighted average is taken into consideration (see Figure 9), the picture changes dramatically for one of the mopeds. The moped YI002 (CARB) showed much higher valures as HC emissions increase by a factor higher than 2. Also CO increases slightly. Cold start does not have such a big impact for the other two mopeds which are equipped with different fuel system technologies (direct injection and electronic carburettor). In fact the increase of CO and HC emission is limited. NOx emissions As expected, the mopeds featuring the direct injection technology (PO003) showed the highest NOx emissions. This had been already noticed in previous in-house studies. Cold start does not affect significantly NOx emissions. CO2 emissions CO2 emissions are directly linked to the fuel consumption. It is clear that the CO2 emissions for a moped are much lower than a passenger car (less than the half compared to a small gasoline car). However, it has to been noted that a moped can carry just one person while a car can carry up to five people.

- 26 -

2.4.2 WMTC driving cycle In addition, the proposed worldwide harmonized test cycle was also used (WMTC). In this case two WMTC were carried out in sequence. The first one is referred to as Cold WMTC_50 and the second one as Hot WMTC_50.

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

YI002 PO003 PTOO1

g / k

mHC CO HC+NOxCold WMTC 50

Figure 12 – Emissions measured over the cold WMTC

0.0

0.5

1.0

1.5

2.0

2.5

3.0

YI002 PO003 PTOO1

g / k

m

HC CO HC+NOx

Hot WMTC 50

Figure 13 – Emissions measured over the hot WMTC

- 27 -

0.00

0.05

0.10

0.15

0.20

0.25

0.30

YI002 PO003 PTOO1

g / k

m

NOx Cold WMTC 50

Figure 14 – NOx emissions measured over the cold and the hot WMTC

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

YI002 PO003 PTOO1

g / k

m

CO2 Cold WMTC

0.0

10.0

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30.0

40.0

50.0

60.0

70.0

80.0

90.0

YI002 PO003 PTOO1

g / k

m

CO2 Hot WMTC 50

Figure 15 – CO2 emissions over the cold and the hot WMTC CO and HC emissions The emission levels measured over the hot WMTC_50 are quite close to the levels measured over the ECE 47. Also the impact of the cold start is quite similar. HC emissions over the cold start are much higher than those for the hot WMTC for moped YI001 and, to a less extent, for moped PT001. NOx emissions Also in the case of WMTC_50, the moped PO003, equipped with the direct injection system, exhibited the highest NOx levels. There was no significant impact of the cold start on NOx emissions. CO2 emissions The CO2 emissions measured over the WMTC_50 cycle are in line with those measured over the ECE47 cycle.

0.00

0.05

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0.20

0.25

0.30

0.35

YI002 PO003 PTOO1

g / k

m

NOx Hot WMTC 50

- 28 -

2.4.3 Effect of the Electronic Carburetor System (ECS) The moped PT001 was equipped with a special Electronic Carburetion System (ECS) comprising an Engine Control Unit (ECU) and electro-actuated carburetor. The system controls the air/fuel mixture and the oil dosing depending on several input parameters (i.e. engine operating conditions). After a first series of tests, the ECS was re-programmed and components were replaced with updated versions by the manufacturer, in order to optimize the emission performance of the moped. The main modifications were:

- Replacement of the secondary air valve with the latest model, that featured a slight improvement in air flow during transient conditions

- Replacement of the catalytic converter with new one - Adjustment of the A/F mixture screw onto the carburetor, due to the above mentioned up-date - Replacement of the semi-synthetic original oil with a fully synthetic one - New calibration of the ECU lubrication map in order to adjust the oil delivery to the leaner A/F

ratio at WOT as well as to reduce the oil flow at light loads (i.e. retain the same oil/fuel percentage at WOT while reducing it at low speeds)

In the following figures the emissions measured before and after the re-programming are compared. The effect of the new settings and the new components are very evident: CO and HC emissions are greatly reduced. This is mainly due to the leaner air/fuel ratio at wide open throttle (WOT) conditions and to the catalyst. On the other side, NOx emissions increased slightly as the air/fuel ratio was leaner. Particulates emissions were reduced especially during the cold phase. This reduction is probably due to the new calibration of the ECU lubricant map as well as to the new catalyst. The leaner air/fuel ratio is also reflected by the lower CO2 emissions.

Effect of ECS settings on emissions PT001(hot phase)

0.0

0.5

1.0

1.5

2.0

2.5

Setting 1 setting 2 Setting 1 setting 2

g/km

HC CO HC+NOx

ECE WMTC

Figure 16- HC, CO and HC + NOx emissions: Effect of two different settings for moped PT001

equipped with a special Electronic Carburetion System (ECS)

- 29 -


0.00

0.02

0.04

0.06

0.08

0.10

0.12


g/km

NOx

ECE WMTC

Figure 17- NOx emissions: Effect of two different settings for moped PT001 equipped with a special

Electronic Carburetion System (ECS)


0.0

20.0

40.0

60.0

80.0


g/km

CO2

ECE WMTC

Figure.18- CO2 emissions: Effect of two different settings for moped PT001 equipped with a special

Electronic Carburetion System (ECS)

- 30 -

2.4.4 Particulate Emissions

HC, CO, and NOx emissions are the only regulated emissions of the two-wheelers. There is no standard procedure to measure PM emissions from two wheelers. Therefore, it was decided to measure PM emissions using the current regulated procedure prescribed for diesel vehicles. The total mass of particulates emitted by a diesel vehicle is measured using a dilution tunnel and CVS (Constant Volume Sampling) system. The diluted exhaust gases are sampled by means of an iso-kinetic probe and then forced to pass through a teflon coated glass fiber filter kept at a temperature that must be below 52 °C and at a pressure close to ambient pressure. The PM can be defined as all the material that is collected on the filter at these conditions. However, in order to avoid contaminating the sampling line and the instrumentation with very large droplets of lubricant emitted by the two-wheelers, the legislative procedure for diesel vehicles was slightly modified inserting a cyclone between the exhaust tailpipe and the transfer line connected to the dilution tunnel. Particulate emissions from moped are, in general, not negligible and sometimes very high. The emission levels are very often comparable with PM emissions from diesel cars not equipped with filters. However, the nature and the composition of particulate emissions from mopeds are completely different when compared to the particles emitted by a diesel vehicle. First of all, the main contributor to PM emission from mopeds is the lubricant mixed to gasoline. Lubricants have boiling points higher than gasoline and, therefore, the mixing process with air takes much more time than gasoline. For this reason particulates emitted by mopeds mainly consists of very small droplets of heavy hydrocarbons essentially coming from the lubricant. The volatile organic fraction of PM reaches levels well above 90% while, for a diesel vehicle, the carbonaceous fraction (soot) is the predominant one. The emissions may vary significantly as a function of: -Vehicles/motorcycles -Fuel and/or lubricant oil (very important if we are talking about 2-strokes) -Load and/or speed. -Cycle (meaning: loading, speed, driving conditions, cold start…) -After-treatment. In-house studies have already shown that the quality of the lubricant has an important effect on PM emissions from mopeds. In general, fully synthetic oils produce less PM than mineral ones. Therefore a very simple measure to reduce significantly PM emissions from mopeds is to force the use of high quality (unfortunately more expensive) lubricants. The measurements performed in this work showed that the three mopeds had similar emissions if the weighted average is calculated according to the proposal described before (30% cold + 70% hot). However, the results referred to the hot phase clearly show that the carburetor equipped mopeds emitted less PM than the moped featuring the direct injection.This means that these mopeds emitted more particulates over the cold phase. In other words, while PM emissions of moped PO003 are quite constant, for the other two mopeds the emissions are high at cold start and decrease once the engine has warmed up.

- 31 -

Figure 19 - ECE 47 combined & Hot ECE47: PM values


0.000

0.005

0.010

0.015

0.020


g/km

PM

ECE WMTC

Figure 20 - PM emissions: Effect of two different settings for moped PT001 was equipped with a

special Electronic Carburetion System (ECS)

0.00

0.01

0.02

0.03

YI002 PO003 PTOO1

g / k

m

PM ECE 47

0.00

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YI002 PO003 PTOO1

g / k

m

PM Hot ECE 47

- 32 -

2.5 Correlation of PM vs HC emissions: Topics to be treated in future projects. It has been already said that PM emissions from mopeds mainly consists of unburned lubricant. For this reason it has been proposed to control PM emissions from mopeds by introducing stricter standards for HC emissions. There are many data showing that there is a good correlation between HC and PM emissions for two stroke engines. However this is not quite true for mopeds equipped with a direct injection system. For mopeds featuring the direct injection technology, it seems that the soot fraction tends to increase and that a particulate emission does not correlate so well with HC emissions as for conventional two strokes carburetted mopeds. If the direct injection technology should become more popular in the near future, it is likely that a limit only on HC emission will not be effective in reducing PM emissions as well.

PM Emissions vs HC Emissions from EURO 1 and EURO 2 MopedsECE 47 - Hot Phase (5-6-7-8)

0

5

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15

20

25

30

35

40

0 0.5 1 1.5 2 2.5

HC (g/km)

PM M

ass

(mg/

km) Euro 2-Carb

Euro 2 - DIEuro 2 - ECSEuro 1 - DI_MinEuro 1 - DI_SintEuro 1 - Carb_Oxy_MinEuro 1 - Carb_Oxy_Sint

DI Engines

Euro 2 with Electronic Carburetors

PM Emissions vs HC Emissions from EURO 1 and EURO 2 MopedsECE 47 - Hot Phase (5-6-7-8)

0

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25

30

35

40

0 0.5 1 1.5 2 2.5

HC (g/km)

PM M

ass

(mg/

km) Euro 2-Carb

Euro 2 - DIEuro 2 - ECSEuro 1 - DI_MinEuro 1 - DI_SintEuro 1 - Carb_Oxy_MinEuro 1 - Carb_Oxy_Sint

DI Engines

Euro 2 with Electronic Carburetors

Figure 21- PM vs HC Emissions represented for EURO1 and EURO 2 mopeds. ECE 47 hot phase.

- 33 -

2.6 Unregulated emissions: Chemical composition of particulate and volatile organic fraction of the vehicular exhaust. The research activity at the JRC-TRANSPORT & AIR QUALTY Unit is not only heading for the physical characterization of the particles emitted by vehicles but also concerned with the investigation of the chemical composition of such emissions, their toxicity and their contribution to air pollution and health risks. It is known from previous studies that unregulated emissions, same as regulated emissions, may vary significantly among: type of Vehicles (i.e. mopeds/motorcycles), fuel and/or lubricant oil (very important for 2-stroke motorcycles), load, speed and type of cycle and after-treatment. There are currently no EU Directive or other guidance for member states which bear directly on PAHs, VOCs or carbonyls from motorcycles emissions. However, the European Commission and the European Parliament have been time ago persuaded through the establishment of the Clean Air for Europe Program and in the last few years, new daughter directives have been put forward with new limits for several of these pollutants in air. The third daughter directive relating with ozone (2002/3/EC) and the fourth daughter directive that covers the remaining pollutants listed in Annex I of the 96/62/EC Directive on Air Quality: As, Cd, Ni, Hg and benzo[a]pyrene (2004/107/EC) Following this demand from the European legislation one of the major challenges for the transport sector is to reduce emissions from vehicles in order to meet future emission standards and to reduce their contribution to the pollution of ambient air and their risk for human health. The challenges for the improvement of air quality in Europe appear to the research field, not only from the technological point of view but also from the research on alternative fuels and better quality lubricants. By means of the experimental procedure described in this report, a significant number of non-regulated, potentially toxic compounds, namely PAH as well as ozone precursors have been identified. The concentrations of these compounds are in the same range as those found either in the literature or in the emissions from similar fuels and technologies. In the following pages, we show the results from the chemical analysis of PAH derivatives adsorbed in the exhaust particulate as well as the equivalent toxicity referred to B[a]P. Quantification of PAH in terms of mass per km, is showed too. Levels of volatile organic compounds in the gas phase of the vehicle exhaust and their contribution to atmospheric ozone formation are also presented.

2.6.1 Chemical analysis of PAH derivatives adsorbed in the exhaust particulate Chemical composition of the soluble organic fraction is important due to its potential relevance for human health. There is a great amount of potentially harmful organic compounds which can be adsorbed on the particles. Polycyclic Aromatic Hydrocarbons (PAH) are ubiquitous environmental contaminants that are formed by the incomplete combustion of organic materials such us wood and fossil fuels and therefore are also present in particulate matter from ambient air and primary sources [3,4]

- 34 -

PAHs molecules are made up of three or more benzene rings, at least two of which are fused with two neighbouring rings sharing two adjacent carbon atoms. PAHs form a large heterogeneous group. Very often, the most toxic compounds of this family are PAHs molecules that have four to seven rings, which have also been included in this report. One of the first chemicals of this family which has been recognized as carcinogenic is benzo[a]pyrene, B[a]P which has been considered in this proposal as a suitable marker due to its stability and relatively constant contribution to the carcinogenic activity of particle-bound PAHs. Due to the lack of legislation of this kind of measurements in emissions regulations, the complete methodology used for the analysis of PAHs in exhaust filters is based on analytical methods that are stablished for the analysis of these compounds in PM proposed by the Air Quality Legislation. In this report, ten priority PAH recommended by EPA because of their mutagenic and, in some cases, carcinogenic properties have been analyzed in particulate matter from vehicle/engine exhaust emissions. All these PAHs are toxicologically relevant organic compounds that are regularly absorbed onto particles.

2.6.2 PAH clean up and analysis: Experimental details The principal steps of PAHs determination are: Sampling, extraction, clean up and analysis. The method used in this work has been developed in our laboratories and is based on the EPA method TO 13 and ISO/DIS 12844. In order to quantify these selected PAHs adsorbed on particulate, total particulate material mass was sampled using Pallflex 70 mm T60A20 filters which are weighed before and after the emission test. The particulate material collected on these filters commonly consists of agglomerates of very small carbon particles (soot fraction) and heavy hydrocarbons adsorbed on them (soluble organic fraction). Knowledge of chemical composition of the soluble organic fraction is important due to its potential relevance for human health. In particular, what is taking our attention is the amount of potentially harmful organic compounds adsorbed on the particles. Among the organic compounds adsorbed on particulates, the present study focused on the detection of ten PAH since there is evidence of the carcinogenicity of these compounds. The reasons for the presence of PAHs in the exhaust gases and adsorbed on particulates are complex and varied. We have listed below some of the most important known:

a. PAHs already present in the fuel that do not undergo the process of combustion.

b. PAHs formation from non PAHs compounds.

c. Transformation of PAHs present in the fuel.

d. PAHs from the fuel absorbed by the lube oil and then released, plus a small amount already present in the lube oil.

PM was collected on standard Teflon coated filters according to the EU current regulated procedures for total mass. Filters were then extracted and evaporated, went through a clean-up procedure, were evaporated again nearly to dryness, dissolved in toluene and finally analyzed by gas chromatography-mass spectrometry (GC-MS).

- 35 -

Sampling was performed in coincidence with the total particulate mass measurement according the legislative procedure. Same filter used to collect the sample and measure the particulate emissions (total mass) was also used to characterize particulates from a chemical point of view. Filters containing particulate material from engine exhaust were extracted in an automatic Soxhlet extractor for 2 h with dichloromethane. The extracts were evaporated nearly to dryness with a “Turbo Vap” System. After reducing the volume, the extract was transferred in a SPE column for the clean-up procedure. The residue including PAHs was passed through a “PAHs soil” solid phase extraction cartridge (J. T. Baker). After removal of non-polar species by elution with hexane, a second fraction was eluted with hexane/dichloromethane (60:40) and successively with acetonitrile/ triethylamine (TEA). Both second and third fractions were collected together. The eluate was evaporated almost to dryness and re-dissolved in toluene and analyzed by GC-MS.

Figure 22 - Filter extraction, evaporation, clean-up and GC-MS analysis

GC-MS analyses were performed with a HP 6890 Series Plus GC system equipped with an auto-injector HP 7683 Series. The mass spectrometer was a 5973 HP Mass Selective Detector equipped with both Electron Impact and Chemical Ionization sources. The column used was a HP-5MS fused silica capillary column, 30 m, 0.25 mm inner diameter, 0.25 μm film thickness. Separation conditions used: injection volume 1 μL in pulsed splitless mode; helium carrier gas at a constant flow rate of 1.0 mL/min; injector temperature 280°C. Run time for one analysis was 36.5 min. EI ionization was employed at 70 eV. MS source temperature was set to 230 °C; MS quadrupole temperature: 150 °C and GC/MS interface temperature: 280 °C. By means of this experimental procedure, a significant number of individual PAHs have been identified. Their concentration and emission factors were in the same range as found by other authors [4].

GC: 6890 HP. MS: 5973 HP Gas carrier: Helium (1 mL / min) Column: HP-5MS (30 m, 0.25 mm, 0.25 mm) Electron ionization (70 eV) SIM - SCAN

EXTRACTION

2 h, DCM

• HEX, 2mL (to waste) • HEX: DCM, 40:60, 10 mL

Surrogate: Chr-D12

SOXLET

Evaporation and change of solvent:

TURBOVAP SPE

CLEAN

HEX

Evaporation and change of solvent:

HEX / DCM / CH3CN

TURBOVA

TOL

TOL (0,5mL)

Internal Standard: MeNa-D10

TOL

Extracted sample in toluene

1 mL

DCM HEX (0,5mL)

GC-

- 36 -

2.6.3 PAH concentration in the particulate exhaust from mopeds In this document we have already reported CO, HC, NOx of three mopeds, however the emission of PAHs and their carcinogenic potency (BaPeq) have seldom been addressed for this type of vehicles. Below, we present results regarding the PAH content that illustrate the behavior of some representative two stroke motorcycles corresponding to Euro 2 emission standards. For all PAHs measurements, the concentration values are expressed in μg/km. We have received two filters for each moped, one corresponding to the cold part of the cycle and one to the hot part which is the one that must be considered when reporting the regulated results. The same criteria are used for PAH concentration. The following summarizes the results on emission factors of ten PAH in the exhaust of the three scooters namely YI, PO and PT investigated under the ECE 47 and the WMTC driving cycle. Focus will be on the hot phase solely and on the combined contemplation of cold phase (CP) and hot phase (HP) with a ratio of 30% CP and 70% HP.

Figure 23: Illustration of the total and individual emission factors of PAH for the three scooters during

the hot phase of driving cycles ECE 47 and WMTC Figure 23 represents the total as well as the individual emission factors of the ten investigated PAH in the hot phase for the three scooters (YI, PO, and PT). Shown are the results for both applied driving cycles ECE 47 and WMTC. Therein, when looking at the total emission factors of PAH, values vary from ca. 6 µg/km (PT, WMTC) to almost 20 µg/km (YI, ECE 47), whereby PT gives the lowest results for both driving cycles, YI the highest in the ECE 47 and PO the highest in the WMTC. Regarding PO both driving cycles result in approximately the same total amount of PAH, whereas YI and PT lead to higher values under the ECE 47 cycle.

Hot Phase

0

5

10

15

20

YI PO PT YI PO PT

µg/k

m

Coronene

Benzo[ghi]perylene

Dibenz[ah]anthracene

Indeno[1,2,3-cd]pyrene

Benzo[a]pyrene

Benzo[e]pyrene

Benzo[k]fluoranthene

Benzo[b]fluoranthene

Chrysene

Benzo[a]anthracene

ECE 47 WMTC

- 37 -

Figure 24- Illustration of the total and individual emission factors of PAH when cold phase and hot phase are combined (30% cold phase + 70% hot phase). Shown are the values for the three scooters as well as for the two driving cycles ECE 47 and WMTC When cold phase and hot phase are considered in combination (referred to as ‘30% CP + 70% HP’), as shown in Figure 24 the emission factors of total PAH are generally higher than for the hot phase solely and range from 13.6 µg/km (PT, WMTC) to 31 µg/km (YI, ECE 47). For both driving cycles PT leads to the lowest amounts, YI leads to the highest, whereby for the latter one the emission factors are higher in the ECE 47 cycle. In contrast, PO and PT lead to similar values for both cycles. Therefore, the overall behavior for the hot phase and ‘30% CP + 70% HP’ is similar and follows the trend that the total PAH is decreasing from YI to PO and PT whereas amounts in the WMTC cycle are lower or of similar size than for the ECE 47. The only exception is the hot phase of PO under the WMTC cycle, which features the highest value of total PAH (instead of being in between YI and PT). However, it has to be taken into account that all these findings are based on two and three replicates, respectively, and the corresponding standard deviations error bars are not considered in these illustrations. When looking at the individual PAH, amounts in ‘30% CP + 70% HP’ are higher than in the hot phase but the overall composition seems to be similar on first sight. However, this should be investigated in more detail. Within each sample the individual PAH are fairly equally distributed with the exception of only a few e.g. Dibenz[a,h]anthracene, where the values are significantly lower.

30% Cold Phase + 70% Hot Phase

0

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20

30

YI PO PT YI PO PT

µg/k

mCoronene

Benzo[ghi]perylene



Benzo[a]pyrene

Benzo[e]pyrene



Chrysene

Benzo[a]anthracene

ECE 47 WMTC

- 38 -

Figure 25- Emission factors of Benzo[a]pyrene for the three scooters and the two driving cycles ECE 47 and WMTC. Standard deviations are based on two and three measurements, respectively Regarding individual species B[a]P is one of the most important PAH to investigate due to its known severe health effects. Subsequently, the emission factors of this compound for ‘30% CP + 70% HP’ are specifically illustrated in Figure 25. In so doing, it can be observed that B[a]P follows the overall trend described earlier i.e. YI features the greatest amount and PT the lowest. Thereby, values span from about 1µg/km to 3µg/km. However, it can also be noted that the measurements’ standard deviations must be taken into account when any conclusions are drawn. Furthermore, in the framework of this study it has been demonstrated that the emission factors of scooters can be reduced tremendously by adjusting engine and injection electronics. This is illustrated in Figure 25 where the emission factors of PAH are compared before and after moped PT was optimized by the manufacturer.

Benzo[a]pyrene

0

1

2

3

4

YI PO PT YI PO PT

µg/k

m

30% Cold Phase + 70% Hot Phase

ECE WMTC

- 39 -

Figure 26- Comparison of the emission factors of the total PAH of PT before and after the ECS was

optimized by the manufacturer The electronic carburetor system (ECS) is a fuel supply and ignition integrated management system which allows accomplishing the future emission standards and to improve the performance of the vehicle. By setting the air/ fuel ratio it may reduce some regulated emissions, mainly CO and HC. Same effect can be observed for PAH emissions (see Figure 26). Therein, it can be noted that for the hot phase as well as ‘30% CP + 70% HP’ the PAH is decreased immensely to even below limits of detection for various compounds. This reduction of PAH due to improved combustion conditions seems to affect all species likewise and might be even more pronounced for the hot phase.

2.6.4 Overall potential toxicity of the Mixture: Particulate toxicity from PAHs

The measurement of the total mass of the particulate is not enough to evaluate its toxicity and carcinogenicity. Furthermore, analysis of the chemical composition of particulate material additionally contributes to a more complete assessment of the impact on human health. In order to evaluate the potential toxicity and carcinogenicity of these pollutants the B[a]P Toxicity Equivalency (TEQ) approach has been used [5]. Thereby, each individual PAH is assigned a toxicity factor (TEF) relative to B[a]P. The B[a]P toxicity equivalent (TEQ) of a given sample is calculated as the sum of each PAH concentration (Ci) multiplied by their TEF over all the measured compounds:

( TEF = “Toxicity Equivalence factor” e TEQ = “Toxicity Equivalence” )

We have applied this approach to the PAH results found in previous studies for the two stroke motorcycles performed in our laboratories [2].

ECE 47

0

5

10

15

PT PT opt. PT PT opt.

µg/k

mCoronene

Benzo[ghi]perylene



Benzo[a]pyrene

Benzo[e]pyrene



Chrysene

Benzo[a]anthracene

Hot 30% Cold Phase+ 70% Hot Phase

TEQ =Σ [ Ci] x TEF i

- 40 -

Figure 27- Total PAH of the three types of scooters for the ECE 47 driving cycle expressed as TEQ µg B[a]P / km. Illustrated are the results for the hot phase and ‘30% CP + 70% HP’ When contemplating total PAH it is useful to transform the results to TEQ values since different PAH feature different levels of toxicity. Figure 27 shows the determined total PAH of the three types of scooters for the hot phase and for ‘30% CP + 70% HP’ of the ECE 47 driving cycle expressed as TEQ in µg B[a]P per kilometer. Therein, it can be seen that the TEQ varies from ca. 1 to 5 µg B[a]P per km with PT generally featuring the lowest values. For both cycles YI leads to the highest results, whereby the one for ‘30% CP + 70% HP’ is more pronounced. In previous in-house experiments several of the PAH were identified in the samples at concentration levels ranging from 0.5-10 μg/km for large motorcycles. Much higher concentrations were found in PM from pre-EURO 1 or EURO 1 moped’s exhaust. The investigated mopeds emit higher amounts of PM and therefore, of toxic compounds if we compare them with EURO 3 or EURO 4 diesel vehicles (see Figure 28). The emissions of PAH from combustion engines depend on many factors: size of the engine, fuel, engine technology, exhaust gas after-treatment and driving mode. Results from 11 different types of PM indicate that are present in engine exhaust from motorcycles. The highest amount of this class of compounds was found in mopeds and varies with the used after-treatment technology. The chemical composition of the PM emitted showed clear differences for emissions coming from cold and hot phases.

ECE 47

0

2

4

6

YI PO PT PT' YI PO PT PT'

TEQ

µg

B[a]

P / k

mHot Phase 30% Cold Phase

+ 70% Hot Phase

- 41 -

0

2

4

6

8

10

12

14

DieselEURO2

DieselEURO3

500ccEURO 1

1200cccatalyst EURO1

CarburatorPre-

EURO1

DirectInjectionEURO 1

Mineralluboil

EURO 1

synthet.luboil

EURO 1

CarburatorEURO 2

Carb. filterCatalystEURO 2

Carb.Filter+oxo catEURO 2

μg

TEQ/

Km

Figure 28- Toxicity equivalence expressed in TEQ (µg/km) for different vehicles.

2.6.5 Volatile emissions from mopeds: NMHC & carbonyls VOCs in combination with oxides of nitrogen are a precursor for the formation of ground level ozone in the presence of sunlight. To prevent the formation of ground-level ozone is one of the driving forces for increasing the studies and the restrictions of these compounds. The Air pollution ozone directive (92/72/EC) passed in 1992 and it was subsequently updated by Directive 2002/3/EC which sets a more stringent alert threshold to replace the warning threshold used in Directive 92/72/EC and sets 120 µg/m3 as long term objective. The various EU limit values proposed to protect crop vegetation and human health are frequently exceeded in all south European countries every year. This situation makes ozone one of the most challenging environmental problems. In the report from 2006 the EEA has quantified that the highest contribution to ozone precursors comes from transport (Approximately 45%) [17]. Being a secondary air pollutant, the formation of ozone depends on the concentrations of the ozone precursors (volatile organic compounds, VOCs) and nitrous oxides. Numerous measurement programs on O3 precursors have clearly shown that traffic emission is the main source in urban areas. If we take into account that in some Southern European regions and developing countries the percentage of two wheelers, mainly mopeds, can raise 60-80% in some urban areas, we can easily conclude that the contribution of these vehicles is extremely important.

2.6.6 VOC speciation

Volatile Organic Compounds (VOCs) are not regulated for any vehicle neither for mopeds emissions. However, since ground-level ozone is one of the air pollutants of most concern in Europe, in the

- 42 -

performed tests it was decided to measure the C2-C9 hydrocarbons, as they present an issue for air quality as ozone precursors. The Ozone Directive 2002/3/EC, in force since 2003, obliges member states to monitor not only ozone itself, but also its photochemically reactive precursors in the air, including the NMHC (non-methane hydrocarbons) or VOCs (Table 2). One of the major objectives of this directive is to assist in the attribution of emission sources to ambient air.

Table 2- The 30 hydrocarbon species (VOCs) recommended to be measured by the Ozone Directive 2002/3/EC. ethane 1,3-butadiene isooctane (2,2,4-trimethyl

pentane) ethene (ethylene) n-pentane benzene ethyne (acetylene) isopentane (2-methylbutane) toluene propane 1-pentene ethylbenzene propene trans-2-pentene m+p-xylene n-butane isoprene (2-methyl-1,3-

butadiene) o-xylene

isobutane (2-methyl propane)

n-hexane 1,2,4-trimethylbenzene

1-butene i-hexane (2-methylpentane) 1,2,3-trimethylbenzene trans-2-butene n-heptane 1,3,5-trimethylbenzene cis-2-butene n-octane

Once emitted in the air, each VOC reacts at a different rate and with different reactions mechanisms, and therefore, it can influence differently the ozone formation at ground level. In urban areas, the major contributor to ozone precursors is road traffic, which is why determining the contribution of hydrocarbons from vehicle emissions is of high importance.

For the present study, three EURO2 2-stroke 50 cc mopeds were tested: two with a carburetor system (named here YI002 and PT001). Moped YI002 has a classical carburetor (CARB) while moped PT001 is provided with an electronic carburetor system (ECS). The third moped, PO003, is provided with a direct injection system (DI). The mopeds were driven on a chassis dynamometer (Zoellner GmbH) with a constant volume sampler (flow 7.5 m3/min). Exhaust samples of the moped were collected in Tedlar™ bags during the driving cycle test and analyzed straight ahead after the sample collection. A sample volume of 80 ml out of the 10 liters collected in the bags was needed for the analysis, allowing replicate analysis when necessary. A thermal desorption unit (UNITY™) and an auxiliary sampling device (Air Server™, Markes International, Pontyclun, UK) were used to collect the samples from the bags. Chromatographic separation and detection were performed with a GC 6890 (Agilent, Wilmington, USA) equipped with a dual flame ionization detector (FID). More details can be found elsewhere [7]. Two driving cycles were performed, namely the ECE 47 (European Motorcycle Test Cycle) and the WMTC (World Motorcycle Test Cycle), the last one developed to replace various existing legislative cycles for two-wheelers (such as ECE in the European Commission), i.e., as an alternative cycle to approve motorcycles [8,9].

The effect of an ECS (Electronic Carburetion System) on emissions was tested for one of the mopeds, namely the PT001. This moped was tested under two different electronic settings of the ECS: a default setting (setting 1) and an optimized setting (setting 2, or OPT). The ECS device was idealized to enhance and control the Air Fuel ratio (A/F ratio), as well as to reduce the oil consumption and the smoke. The presence of ECS is expected to reduce effectively HC and CO emissions, but not to solve NOx.

- 43 -

2.6.7 VOCs speciation over ECE 47 and WMTC driving cycles The results discussed in this section come out from a complete dataset for VOCs based on replicate experiments. The sum of the speciated hydrocarbons emitted by each fuel was calculated as propane equivalents in order to be compared to the THC measured online. It must be pointed out that the THC value (6.6 ± 0.2 g/km) measured for the YI002 when performing the ECE test was much higher than for any other moped in this study. In a previous study an emission factor for a 50 cc moped has been found to be 1.56 g of THC per km [10]. The mean value for THC found in the present investigation is higher (≥2 g/km) for all investigated mopeds. As expected, the VOCs emissions resulted to be lower than the THC. First of all because the 30 hydrocarbon species determined by the VOCs method represent only a subset of all VOCs known to be emitted by vehicle exhaust (>300 species) and secondly, because the THC method is based on the assumption that propane can be used as a representative calibrant for all VOCs. In particular, 2-stroke exhaust is expected to contain a large fraction of high molecular weight hydrocarbons (deriving from the oil fraction of the fuel) which gives a response by the THC measurement but is not included in the VOCs measurements. To have an overview of all conditions studied, the sum of the speciated hydrocarbons (emitted by each moped over each cycle) was calculated as propane equivalents and plotted together with the THC value (refers to the THC measured over the whole cycle, named here “combined”) as can be seen in Figure 29. Results showed differences in total emissions from moped to moped. The statistical analysis of data showed that for THC there is a significant difference between mopeds (p<0.001) and there is an effect of ECS settings’ optimization (p<0.001) independently of cycle and of specie. As expected, the VOCs emissions resulted to be lower than the THC for each condition studied, ranging from 13 to 42%. Literature data [11] has showed much higher ratios (from 59 to 76%) for 2-stroke motorcycles. Except for YI002, all mopeds and conditions showed comparable or slightly higher ratios for the WMTC cycle compared to the ECE cycle. Values from 0.3 to 0.9 g/km and from 2 to 6 g/km were found for VOCs and for THC respectively. The moped PO003 gave generally the lowest values for VOCs and for THC. The values were comparable to the ones found for the moped PT001 when equipped with the ECS. The lowest values of emissions both for VOCs as for THC were found for moped PT001+new setting (ECS OPT) over the WMTC cycle. Regarding the optimized ECS setting, the reduction for the moped PT001 was more efficient for the WMTC cycle. For THC it corresponded to 34 and 45%, and for VOCs it corresponded to 28% and 46% (ECE and WMTC cycle) respectively.

- 44 -

0

2

4

6

8

ECE WMTC ECE WMTC ECE WMTC ECE WMTC

g / k

m

VOCs (C3) THC

YI002 PO003 PT001 PT001(new settings)

6.6 ± 0.6

Figure 29– Mean values for VOCs and for THC emissions, in g/km (VOCs calculated here as propane

equivalents; 95% confidence interval depicted). Moped PT001 was equipped with an Electronic Carburetor System (ECS). The optimization of ECS settings is, therefore, efficient on reducing VOCs, although no differentiated reduction among the different hydrocarbons seems to occur, which can be seen in Figure 30.

Effect of ECS settings (optimization)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

setting 1 setting 2 setting 1 setting 2

g/km

1,2,4-tri-methyl benzene1,3,5-tri-methyl benzeneo-xylenem-xyleneethyl-benzenetoluenebenzenen-heptanen-hexaneisoprenecyclo-hexane+3-methyl-pentane2-methylpentanecis-2-pentenetrans-2-pentenen-pentane1,3-butadieneiso-pentane (2-methyl-butane)propynecis-2-buteneisobutene1-butenetrans-2-butenen-butaneiso-butaneacetylenepropenepropaneetheneethane

- 26%

- 46%

ECE WMTC

Figure 30– Reduction effect of ECS settings optimization on VOCs emissions for ECE and WMTC cycles (moped PT001). Setting 1 refers to default settings of ECS; setting 2 stands for optimized ECS settings (OPT).

- 45 -

The statistical analysis showed, though, that, independently of test cycle and of compound (for benzene, 1,3-butadiene, ozone), there is a significant effect of ECS settings (ANOVA: p = 0.037) on emissions. In order to better visualize the changes when using an optimized ECS setting regarding the fraction of each VOC, their relative contributions for each moped and cycle were depicted in Figure 31. Here, it can be observed that there is a very similar pattern for all conditions and mopeds, meaning that no preferential reduction occurs from moped to moped, neither with optimized or default ECS settings. Furthermore, the profile of the speciated hydrocarbons emitted by mopeds is predictable and therefore very much indicated for modelling and source apportionment studies [12], as for example, in the usual approach of B/T ratio (benzene/toluene) to study air pollution transport [13]. After a closer look at Figure 31, it is possible to conclude that, by far, the highest contribution to emission of mopeds is given by the C5 hydrocarbons (up to ~ 40%), followed by ethene, isobutene, propene, acetylene and xylenes, in this order, decreasingly. The absolute values (in mg/km) found for each speciated hydrocarbon investigated in the present study are shown in Table 3. Some former results obtained in our group [14] are also shown for comparison. All data refer to the emission of mopeds over an ECE cycle. The results have shown comparable values for DI mopeds EURO1 (former results) and EURO2 (moped PO003), although the sum of total VOCs was lower for the EURO 1 moped, but still similar to the moped PO003 which is a EURO2, and to the moped PT001 OPT (EURO2, optimized carburetor settings).

- 46 -

Table 3– Emissions values for speciated VOCs from 2-stroke mopeds pre-EURO1, EURO1 and EURO

2 (values in mg/km ± sd).

mg/km Pre-EURO1a EURO-1, CAT a EURO1, LPG a EURO1, DI a EURO 2,

CARB (YI002) b

EURO2, ECS

(PT001) b,c

EURO2, ECS

(PT001, OPT) b,d

EURO2, DI

PO003 b

Ethane 33.7 ± 9.8 25.1 ± 0.9 38.9 ± 24.5 1.1 ± 0.01 34.8 ± 1.9 27.3 ± 1.7 14.4 ± 4.1 11.9 ± 0.5 Ethene 396 ± 56.4 288 ± 29.6 293 ± 102 45.9 ± 4.5 116.8 ± 6.6 65.3 1± 2.5 39.8 ± 12.5 30.9 ± 0.9 Propane 3.5 ± 0.5 2.2 ± 0.4 85.4 ± 4.5 0.3 ± 0.01 2.6 ± 0.2 1.1 ± 0.1 1.3 ± 1.0 0.9 ± 0.1 Propene 210 ± 21.4 149 ± 10.0 259 ± 21.8 26.5 ± 2.5 84.4 ± 5.2 45.8 ± 7.9 26.5 ± 9.2 22.1 ± 0.1 Acetylene 301 ± 13.9 131 ± 5.8 17.2 ± 3.0 18.1 ± 1.6 63.0 ± 4.6 33.4 ± 17.3 30.9 ± 13.5 40.2 ± 2.4 Isobutene 70.4 ± 7.7 22.7 ± 2.3 801 ± 78.6 6.8 ± 0.7 10.0 ± 0.7 3.5 ± 0.5 5.9 ± 2.6 3.5 ± 0.3 n-butane 73.1 ± 8.1 26.5 ± 2.3 841 ± 135 6.9 ± 0.2 24.0 ± 1.3 11.7 ± 1.7 12.9 ± 5.8 10.3 ± 0.5 trans-2-butene 25.5 ± 3.2 13.9 ± 0.9 30.3 ± 6.4 3.3 ± 0.8 8.1 ± 0.2 4.8 ± 0.6 2.5 ± 1.0 3.0 ± 0.1 1-butene 23.9 ± 1.6 14.2 ± 2.2 27.9 ± 2.8 2.3 ± 0.4 17.3 ± 1.1 7.2 ± 1.5 5.3 ± 2.0 4.7 ± 0.2 Isobutene 71.0 ± 11.3 43.5 ± 3.6 22.6 ± 5.4 10.4 ± 0.8 88.1 ± 7.8 44.8 ± 6.4 24.6 ± 8.9 30.2 ± 0.7 cis-2-butene 10.4 ± 1.3 6.0 ± 1.0 12.0 ± 1.8 1.2 ± 0.4 6.7 ± 0.2 1.9 ± 1.8 1.1 ± 1.3 2.3 ± 0.1 Propyne 22.3 ± 3.2 23.7 ± 3.0 7.3 ± 0.2 3.1 ± 0.6 6.0 ± 5.1 3.2 ± 1.2 3.6 ± 1.6 1.9 ± 0.1 Isopentane 466 ± 27.8 127 ± 9.0 13.2 ± 2.3 44.4 ± 3.7 204.2 ± 9.9 117.2 ± 26.2 97.4 ± 41.5 95.2 ± 2.1 1,3-butadiene 193 ± 11.5 49.3 ± 3.5 7.9 ± 0.04 8.9 ± 0.7 25.1 ± 5.0 10.7 ± 3.7 5.3 ± 2.1 3.8 ± 0.7 n-pentane 742 ± 63.0 29.9 ± 3.1 2.0 ± 2.1 7.7 ± 0.2 31.2 ± 6.8 28.4 ± 5.7 28.2 ± 22.0 16.6 ± 2.7 trans-2-pentene 10.9 ± 0.7 3.8 ± 0.4 0.2 ± 0.2 1.8 ± 0.1 5.4 ± 3.0 4.0 ± 4.1 4.5 ± 1.8 2.1 ± 0.1 cis-2-pentene 4.7 ± 0.4 1.7 ± 0.5 0.1 ± 0.1 0.4 ± 0.1 3.8 ± 0.2 1.2 ± 0.9 1.6 ± 0.8 1.0 ± 0.1 methylpentanes 660 n.d. 342 ± 14.9 0.7 ± 0.7 111 ± 8.3 68.5 ± 14.6 38.5 ± 13.2 35.3 ± 19.2 29.6 ± 12.7 Isoprene 9.0 ± 1.8 3.2 ± 1.1 1.1 ± 1.1 1.0 ± 0.3 12.6 ± 1.0 3.7 ± 0.6 2.9 ± 1.1 2.1 ± 0.1 n-hexane 9.4 ± 1.2 3.3 ± 0.2 0.9 ± 0.9 0.8 ± 0.1 15.1 ± 1.4 1.4 ± 0.4 3.0 ± 1.2 3.1 ± 0.4 n-heptane 4.0 ± 4.1 3.6 ± 1.3 0.1 ± 0.1 1.0 ± 0.01 11.4 ± 2.4 5.6 ± 2.0 4.4 ± 1.7 6.1 ± 0.2 Benzene 14.6 ± 1.5 12.0 ± 0.04 1.3 ± 1.2 2.7 ± 0.2 18.6 ± 1.6 9.1 ± 1.9 6.8 ± 2.1 6.9 ± 0.3 Toluene 162 ± 20.8 89 ± 30.9 1.6 ± 1.8 18.9 ± 3.1 55.5 ± 13.4 28.3 ± 9.5 17.8 ± 7.3 27.4 ± 1.9 Ethylbenzene 31.8 ± 8.1 12.6 ± 3.0 n.d. 5.6 ± 1.6 11.1 ± 9.3 10.6 ± 3.6 5.6 ± 2.7 10.0 ± 0.5 M+p-xylene 39.3 ± 10.3 14.9 ± 6.0 n.d. 7.3 ± 2.4 47.2 ± 14.6 24.4 ± 8.0 14.1 ± 6.9 24.2 ± 1.3 o-xylene 23.6 ± 7.1 5.5 ± 1.6 n.d. 2.7 ± 0.9 24.5 ± 7.0 10.3 ± 3.1 6.7 ± 3.2 11.2 ± 0.8 1,3,5- trimethylbenzene

2.6 ± 0.7 1.2 ± 0.6 n.d. 1.4 ± 0.2 10.8 ± 3.4 1.7 ± 0.3 1.6 ± 0.8 3.4 ± 0.9

1,2,4- trimethylbenzene

5.9 ± 3.4 3.5 ± 2.0 n.d. 1.6 ± 0.2 6.1 ± 2.2 2.3 ± 0.3 1.8 ± 1.2 2.6 ± 0.4

Sum of VOCs (g/km)

3.4 ± 0.18 1.4 ± 0.11 2.5 ± 0.19 0.34 ± 0.03 1.01 ± 0.06 0.55 ± 0.13 0.41 ± 0.17 0.41 ± 0.07

a From former results [14]. b From present investigations. c With default settings (setting 1) of ECS. d With optimized settings (setting 2) of ECS.

- 47 -

VOCs relative emissions

0.0

0.2

0.4

0.6

0.8

1.0

YI002 PT001 PT001 +OPT

PO003 YI002 PT001 PT001 +OPT

PO003

g / k

m1,2,4-tri-methyl benzene

1,3,5-tri-methyl benzene

o-xylene

m-xylene

ethyl-benzene

toluene

benzene

n-heptane

n-hexane

isoprene

cyclo-hexane+3-methyl-pentane

2-methylpentane

cis-2-pentene

trans-2-pentene

n-pentane

1,3-butadiene

iso-pentane (2-methyl-butane)

propyne

cis-2-butene

isobutene

1-butene

trans-2-butene

n-butane

iso-butane

acetylene

propene

propane

ethene

ethane

ECE WMTC

Figure 31- VOCs relative contribution for the three mopeds over the ECE and the WMTC cycle. The abbreviation PT001+OPT stands for optimized settings, or “setting 2” of the ECS (Electronic Carburetor System). Still regarding the optimization of the ECS, a very important finding for VOCs was a significant reduction for the toxic and carcinogenic compounds 1,3-butadiene and benzene [15,16] (for the ECE cycle, 50% and 25% reduction, respectively); the potential for ozone formation was reduced to 65% of the original value found for the moped PT001 with default ECS settings (ozone formation potential will be discussed later elsewhere in this report). This can be seen in Figure 32, as well as in Table 3. In Figure 32, the average absolute values found for 1,3-butadiene and benzene were depicted, together with the ozone formation potential (for the latter, results were divided by a factor of 100 for graphical enhancement). Analysis of the data showed that there is a statistically significant effect of emissions of ozone, benzene and 1,3-butadiene between mopeds (ANOVA: p=0.04) but not on the test cycle (p=0.23). Values of ozone potentials are comparable with literature data found for 2-stroke motorcycles (5.66 g-O3/km) [11]. In the present study, values for 1,3-butadiene ranged from 3 to 25 mg/km, and for benzene from 7 to 19 mg/km, which is comparable to former data for EURO1 mopeds from our group [14], and in agreement with literature data [17], where comparable results were observed for 1,3-butadiene, benzene and xylenes. In addition, it is quite a high value, compared to other LD vehicles running on gasoline or diesel. These high emission factors must be kept in mind when evaluating the possible impact on the environment and on health of an increase in the mopeds fleet.

- 48 -

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08


PO003 YI002 PT001 PT001 +OPT

PO003

g / k

m

1,3-butadiene benzene Total O3, g/km ( : 100 )

ECE WMTC

Figure 32- Emissions of 1,3-butadiene, benzene and ozone potentials (95 % confidence interval). Results for ozone are divided by 100 for graphical enhancement. The abbreviation PT001+OPT stands for optimized settings, or “setting 2” of the ECS (Electronic Carburetor System).

2.6.8 Ozone formation potential of VOCs The relative contribution of each individual VOC to the potential ozone formation can be estimated by the Maximum Incremental Reactivity (MIR) approach [18]. The technical background for this approach is as follows: Carter used a chemically detailed box model to quantify the ozone formed from 180 different VOC in 39 cities across the United States. Eighteen different reactivity scales were developed from those model calculations. The scales differ in the assumptions about the levels of NOx and the measure of ozone impact (such as impact on the peak ozone versus integrated impact over time). One scale, the Maximum Incremental Reactivity (MIR) scale, was chosen for regulatory application in California. MIR values for individual VOCs were calculated in 10-hour box model simulations and were defined as the maximum sensitivity of the peak ozone concentration ([O3]p) to a small increase in the initial conditions and emissions of the VOC (Ei). MIR is determined for the input ratio of VOC to NOx that leads to the maximum sensitivity to VOC:

[ ]

⎭⎬⎫

⎩⎨⎧

∂

∂=

i

pi E

OMIR 3max (eq.1)

over all VOC/NOx. Using the calculated MIR values, it is possible to calculate the potential of ozone formation for each of the VOCs ( 3PO ), according to the equation:

- 49 -

∑⎭⎬⎫

⎩⎨⎧

⎥⎦⎤

⎢⎣⎡×⎥

⎦

⎤⎢⎣

⎡=⎥⎦

⎤⎢⎣⎡

i ii kmgE

gVOCgOMIR

kmgPO 3

3 (eq. 2)

The potential of ozone formation for each individual hydrocarbon present in the moped exhaust was estimated by the MIR approach. It ranged from 1 to 1136 mg of O3 / km, and when the ECS was optimized it decreased by 34% and 44%, for ECE and WMTC cycles respectively. The average relative contribution of the individual VOCs to the 3PO for the different cycles is depicted in Figure 33, where again a very similar profile, or fingerprint, was found for all conditions investigated, namely different mopeds and technologies. The general fingerprint shows a prevalence of ethene and propene up to 40% of the total potential, followed by an important contribution of up to 20% of C4 hydrocarbons and of xylenes, and finally, of around 15% of C5 and C6 hydrocarbons in the mopeds exhaust. These results, together with the important contribution of 1,3-butadiene, highlight the importance of the performance of VOC analyzers in the C2-C9 range. Relative Ozone formation potential for VOCs

0.0

0.2

0.4

0.6

0.8

1.0


PO003 YI002 PT001 PT001 +OPT

PO003

g O

3 / k

m

1,2,4-tri-methyl benzene1,3,5-tri-methyl benzene

o-xylenem-xyleneethyl-benzene

toluenebenzenen-heptanen-hexaneisoprenecyclo-hexane+3-methyl-pentane

2-methylpentanecis-2-pentenetrans-2-pentene

n-pentane1,3-butadiene

iso-pentane (2-methyl-butane)propynecis-2-buteneisobutene1-butenetrans-2-butene

n-butaneiso-butaneacetylene

propenepropaneetheneethane

ECE WMTC

Figure 33– VOCs relative contribution to ozone formation for ECE and WMTC cycles. The abbreviation PT001+OPT stands for optimized settings, or “setting 2” of the ECS (Electronic Carburetor System). The comparison of our present findings for mopeds with former results of our group [14] regarding the potential for ozone formation is shown in Figure 34. Former results for 2-stroke mopeds (running on

- 50 -

gasoline and LPG) and for gasoline and diesel cars are also depicted. Compared to the mopeds investigated formerly, the mopeds investigated here showed a lower percentage of ethene, propene and 1,3-butadiene. On the other hand, there was an important increase on the contribution of isobutene and visibly higher of xylenes in the formation of ozone. The adequacy of mopeds profile for source apportionment, again, is very clear, since their fingerprint is very much alike and invariable. Besides the very well known fact that gasoline cars emit more VOCs than diesel cars, it is also clearly seen that there is a difference between relative contributions of each speciated hydrocarbon when vehicle or fuel is changed.

VOCs responsible for >90% of ozone formation

0

25

50

75

100

Pre-EURO1

EURO-1, C

AT

EURO1, LPG

EURO1, DI

EURO2, CARB

EURO2, ECS

EURO2, ECS+OPT

EURO2, DI

Gasolin

e car, E

URO3

Diesel c

ar, EURO3

%

1-butenexylenestolueneisobutanen-butaneisopentanemethylpentanes1,3 butadieneisobutene2-butenespropeneethene

Figure 34– VOCs contribution for ozone formation, considering the fraction of speciated VOCS

responsible for more than 90% of the emissions. Results over the ECE cycle for mopeds, present and former results [8]. Mopeds 50cm3, 2-strokes; gasoline car EURO3, 1.2L MPI stoichiometric, 3-way CAT; diesel car EURO3, 1.9L, Turbo, DI common rail, oxidative CAT.

2.6.9 Carbonyl Compounds Carbonyl compounds are also major constituents in urban atmosphere. In city areas, these compounds often initiate photochemical smog and keep up reactions leading to ozone formation by an oxidation process involving OH radicals, ozone, and nitrogen oxides in a cyclic mechanism. Main outdoor sources of carbonyl compounds include motor vehicle exhaust and other forms of incomplete hydrocarbon combustion particularly industrial sources. The list of volatile organic compounds which are recommended to be observed in the ozone directive [2002/3/EC], already includes formaldehyde. However, these 30 compounds are not the only ones which intensively contribute to ozone formation. In general the carbonyls play an important role in the atmospheric chemistry and, more precisely, formaldehyde (HCHO) is a good tracer of photo-oxidation

- 51 -

and thereby of pollution from fossil fuel combustion and of biomass burning. Therefore the objective of this part of the work was the analyses and quantification of formaldehyde and other carbonyl compounds. Our target was to get a better knowledge of the emissions of these volatile chemical species from small motorcycles (mopeds) which may have a considerable impact on air quality of urban Mediterranean areas. The quantification of these compounds is very important since we have found a considerable amount of them which are not present in the emissions of other type of vehicles (i.e. LD or HD).

2.6.9.1 Sampling & analysis methodology In Europe, carbonyls are not included in any monitoring protocol in the vehicle exhaust stage and their concentration is not measured on a regular basis. In the absence of any regulation and emission control of these pollutants we found a lack of references regarding the limits which could be acceptable or satisfactory for this group of compounds. The analytical method used here has been developed on the basis of the “compendium of Methods for the Determination of Toxic Organic Compounds in AmbienT Air (2nd Edition)” [EPA/625/R-96/-1-b]; Compendium Method TP-11A: Determination of Formaldehyde in Ambient Air Using Absorbent Cartridge Followed by High Performance Liquid Chromatography (HPLC). Sampling was done according to the standard of the European Monitoring network, EMEP [19]. The air sample (flow 0.9-1 l/min) was drawn through the 2,4-dinitrophenylhydrazine (DNPH) coated C18 cartridges (Waters Sep-Pak DNPH-cartridges). Carbonyls are hereby collected as their non-volatile 2,4-dinitrophenylhydrazone derivatives. These cartridges were eluted in the laboratory with 2.5 ml of acetonitrile, diluted with 2.5 ml of H2O and stored at 5°C until analysis. The samples were analysed by HPLC-UV (high performance liquid chromatography) with a thermostated (20°C) 30 cm x 3.9 mm C18-coated silica gel (4μm) column (NOVO-PAK) run in the gradient mode (0.9 ml/min). Detection and quantification were carried out at 360 nm. The eluents were H2O (A-eluent) and acetonitrile (B-eluent). The gradient was programmed from 50% B to 90% B in 42 min. The detection limit for this method was in the range of 5-20 ng for formaldehyde hydrazone (S/N = 3). Samples volumes of 20 l were taken in DNPH cartridges. Values of acetaldehyde, acrolein and acetone as well as propionaldehyde have been also quantified. It has not been possible to separate chromatographically the two picks corresponding to acrolein and acetone. By means of the chromatographic method used these two compounds are coming together as already reported by other authors [20].

2.6.9.2 Experimental results 13 carbonyls emitted from three different mopeds have been analyzed and quantified. All tests have been conducted following two different driving cycles: ECE 47 and WMTC 50. In addition, one of the three mopeds (PT001) has been tested with the application of the ECS (Electronic Carburetion System). For all mopeds, conditions, and carbonyls the WMTC cycle tended to produce slightly lower emissions than the ECE cycle. However, the result was not statistically different (P=0.23). This difference reflects the fact that during the ECE 47 cycle there is a rather higher consumption of fuel.

- 52 -

Results show that the three mopeds without the ECS behave generally the same and the differences on the overall carbonyls emissions are variable (up to 26%). The PO003 is the one with the highest emissions, followed by YI002 and PT001. In the following figure the emissions measured before and after the re-programming of moped PT001 are shown. This new system with the new configuration is also capable of electronic lubrication control. As we can see in Figure 35, there is a patent effect of the ECS optimization moped PT001 over its emissions. The effect of the new settings for this moped is evident. The results revealed a significant (P=0.03) reduction in carbonyls in the range of 49% with the application of new settings of the moped with the ECS. Formaldehyde and acetaldehyde together build up between 67% and 83% of all the carbonyls emissions, where formaldehyde is the carbonyl emitted in a higher quantity, up to 20 mg/Km. Together with formaldehyde and acetaldehyde, other 11 carbonyls have been quantified (acrolein, acetone, propionaldehyde, crotonaldehyde, methacrolein, 2-butanone, butyraldehyde, benzaldehyde, valeraldehyde, p-tolualdehyde and hexanaldehyde). It is worth to mention that all these compounds have not be found (under detection limit) in previous analysis of carbonyls for LD vehicles. The sum of these eleven compounds ranges from the 17% of the total amount of carbonyls in the moped PT001 with ECS- optimized up to 26% of the total for the moped YI002 with carburetor.

Carbonyl emissions for MOPEDS [mg/km]

0

4

8

12

16

20

24

ECE 47 WMTC ECE 47 WMTC ECE 47 WMTC ECE 47 WMTCCycles

mg/

km

FormaldehydeAcetaldehydeAcrolein+AcetonePropionaldehydeCrotonaldehydemethacrolein2-butanone & ButyraldehydeBenzaldehydeValeraldehydep-TolualdehydeHexaldehyde

PT001- F1

PT001- F2

YI002 PO003

Figure 35- Emissions of carbonyls (95 % confidence interval). The abbreviation PT001-F2 stands for

optimized settings of the ECS (Electronic Carburetor System).

- 53 -

Conclusions Two stroke engines mopeds are still very popular in urban areas and their contribution to overall road transport emissions must be considered due to the significant emission reductions from light and heavy duty vehicles. In general, it can be said that the new available technologies for mopeds may lead to a considerably reduction of the emissions both regulated and non-regulated. The improvement is very much dependent of the following factors:

• Driving cycle and driving cycle phase • The pollutant considered • Vehicle technology and engine settings • Engine operating conditions

During the whole test program, mopeds showed a decrease of emissions if compared with previous EURO stages. Emissions are in good agreement with those obtained for similar vehicles tested previously in our laboratories and/ or in the literature. The following conclusions can also be pointed out: • ECE 47 cycle CO and HC emissions All the mopeds complied with the Euro 2 limits when tested over the legislative cycle. However, when the cold part of the cycle is taken into consideration (weighted average: 30/70) the picture changes for moped CARB and it does not comply any more with the emission standards. Cold start did not affect the other two mopeds which are equipped with different fuel system technologies (direct injection and electronic carburetor). NOx emissions As expected, the mopeds featuring the direct injection technology showed the highest NOx emissions. Cold start does not affect significantly NOx emissions. CO2 emissions CO2 emissions are directly linked to the fuel consumption. It is clear that the CO2 emissions for a moped are much lower than a passenger car (less than the half compared to a small gasoline car). • WMTC cycle CO and HC emissions The emission levels measured over the hot WMTC are quite close to the levels measured over the ECE 47. Also the impact of the cold start is quite similar. HC emissions over the cold start are much higher than those for the hot WMTC for moped YI001 and, to a less extent, for moped PT001. NOx emissions Also in the case of WMTC cycle, the moped equipped with the direct injection system, exhibited the highest NOx levels. No significant impact of the cold start on NOx emissions. CO2 emissions The CO2 emissions measured over the WMTC cycle are in line with those measured over the ECE 47 cycle.

- 54 -

PM emissions Carburetor equipped mopeds emitted more PM during the cold start than when the engine is warmed up. Opposite behavior was noticed for the moped featuring the direct injection system. The DI moped emits more than the carbureted mopeds over the hot phase and less during cold start. • ELECTRONIC CARBURATOR SYSTEM

o The new settings for moped PT showed a noticeable improvement in the quality of regulated and non-regulated emissions

o The effect of the new settings and the new components are very evident: CO and HC emissions are greatly reduced. On the other side, NOx emissions increased slightly as the air/fuel ratio was leaner. Particulate emissions were reduced as well especially during the cold phase. The leaner air/fuel ratio is also reflected by the lower CO2 emissions.

o Moped with this technology is also the one that had a slightly better behavior in terms of PAH and so for TEQ. Also the results for VOC, their corresponding ozone potential formation as well as carbonyls emissions were found to be better.

• PAH emissions and toxicity equivalence

o The type of engine and its setting has a great influence on the compounds found in the PM. The chemical composition of the PM emitted showed differences for emissions from cold and hot phases

o The carburator moped, YI002, results in the highest emission factors of total PAH for the ECE

47 cycle either considering only hot part of that cycle or the weighted average (30% Cold/ 70% hot). The moped with DI leads to the highest amount for the WMTC in the hot phase.

o The moped with ECS showed the lowest emission factors for total PAH in all tests. The lowest

PAH emission was obtained when the moped with ECS was upgraded with new settings.

o Emission factors in the weighted average of the ECE 47 cycle (30% Cold/ 70% hot) are higher than in the hot phase. However, the overall composition/ distribution on PAH seem to be very similar. Most individual PAH occur in similar quantities.

o PAHs content of the PM, and so their potential toxicity, may be higher with a conventional

carburator or with a DI system than it is with ECS. The ECS setting has a positive influence on the quality of the emissions in terms of toxicity.

• VOCs speciation with the ECE 47 and WMTC cycles:

o The VOCs emissions for the different mopeds corresponded to 13 to 42% of the THC value. Values of 0.3-0.9 g/km were found for the sum of speciated VOCs. Results for the ECE cycle were comparable to results for the WMTC cycle.

o The optimization of the ECS caused a reduction in VOCs emission of 26% and 46% for the ECE and WMTC cycles, respectively. No compound-preferential reduction could be observed.

o The relative contribution of VOC species was comparable to the literature. A very similar pattern for all mopeds and conditions was observed, with a prevalence of about 40% of C5 hydrocarbons, followed by ethene, isobutene, propene, acetylene and xylenes.

o Emissions of benzene and 1,3-butadiene (3-25 mg/km and 7-19 mg/km respectively) were found to be dependent on the type of moped.

- 55 -

• Ozone formation potential of VOCs:

o Contributions from ethene and propene prevailed (< 40%), followed by C4 hydrocarbons and xylenes (< 20%), and by C5 and C6 hydrocarbons (<15%).

o The present results (EURO2 mopeds) were compared with EURO1 mopeds and showed a lower percentage of ethene, propene and 1,3-butadiene, with an increased percentage of isobutene and xylenes.

o The pattern for VOCs emissions was proven to be very characteristic and invariable, markedly different however when fuel or vehicle type is changed, being therefore very suitable for source apportionment studies.

• Carbonyl emissions:

o Results from four different types of mopeds indicate that a number of carbonyls are present in engine exhaust from 2-stroke motorcycles. The highest amount of this class of compounds was found for the moped provided with DI system (38 mg/km emitted for the ECE 47 cycle and 33 mg/km emitted during the WMTC cycle.

o For all mopeds, conditions, and carbonyls the WMTC cycle tend to produce slightly lower emissions than the ECE cycle

o The effect of new settings for moped with ECS is very positive. The results revealed a significant reduction in carbonyls in the order of 49% with the application of new settings of the moped with the ECS.

- 56 -

3. TWO-STROKE ENGINES VERSUS FOUR-STROKE ENGINES: COMPARISON OF EMISSIONS

In general, motorcycles and mopeds exhibit very different emission patterns due to the different type of engine. Most of the modern motorcycles are equipped with four-stroke engines while the vast majority of the mopeds (having a displacement below 50 cc) are still equipped with two-stroke engines.

Emission levels from several 2-stroke mopeds and 4-stroke motorcycles tested at the JRC have been compared.

Fleet used in the experiments:

Category Motorcycles Eng. (cc) 2S 4S

Emission St Engine / After-treatment

characteristics

Moped MT001 50 X Pre-Euro1 Standard 2-stroke engine Moped MT002 50 X Euro1 Ditech Engine, Electronic injection Moped MT003 50 X Euro1 Moped, With Catalyst

Moped MT004 50 X Euro2 Carburetor Moped MT005 50 X Euro2 Direct injection Moped MT006 50 X Euro2 Electronic Carburator System

125cc MT007 125 X Euro1 Controlled TWC 125cc MT008 125 Euro1 Carburetor 200cc MT009 200 X Euro1 Carburetor

>450cc MT010 500 X Euro1 Catalyst

>1000cc MT011 1150 X Euro1 Controlled TWC (Three Way Catalyst)

>1000cc MT012 1200 X Euro1 Controlled TWC (Three Way Catalyst)

The emissions were measured according to the relevant type approval procedure. The legislative cycle for mopeds is different from the driving cycle prescribed for motorcycles. Nevertheless, since in all cases the emissions are expressed in g/km and considering that mopeds and motorcycles are anyway driven in a different way in the real world, the values can be directly compared. The results of this comparison for the regulated pollutants and CO2 emissions are shown in Figures Figure 36-Figure 39 The plots clearly show that 2-stroke engines have higher HC emission than 4-stroke engines, with the exception of mopeds equipped with direct injection engines (MT002-2S-50 and MT005-2S-50). This is due to the characteristic of the two-stroke cycle: it combines the compression phase with the expulsion of the combustion gases from the cylinder, with the exhaust gas being displaced by the fresh gas (scavenging process). In conventional two-stroke engines, during the scavenging phase fresh gas and exhausts unavoidably mix together to a certain extent and, as a result, part of the fresh gas is expelled from the cylinder with the exhaust. Similarly, part of the exhaust gas is retained within the cylinder and take part to the subsequent combustion process; this is de-facto an internal “exhaust gas recirculation (EGR)” which is very effective in reducing NOx emissions. The

- 57 -

expulsion of fresh gas and the internal EGR explain why two-stroke engines have such high total hydrocarbon emissions and very low NOx emissions compared to four-stroke engines as shown in Figure 3.3. The implementation of the direct injection technology in two-stroke engines overcomes this problem by injecting the fuel directly in the combustion chamber. However, this technology changes completely the emission pattern of the engine. In fact, as shown in Figure 36-Figure 39, the mopeds MT002-2S-50 and MT005-2S-50, which are equipped with a direct injection engines, exhibit low HC and PM emission but much higher NOx emission compared to the other mopeds featuring conventional two-stroke engines. If 4-stroke engines are in general much better than 2-stroke engine in terms of HC emissions, the situation is completely different for CO and NOx emissions. As shown in Figure 37 and Figure 38, CO and NOx from 4-stroke engines are higher than from 2-stroke engines. Of course, if the motorcycle is equipped with a three way catalyst all the emission are greatly reduced and may reach the typical levels of catalysed passenger cars. However, tests performed on motorcycles equipped with a catalytic converter have shown that often the efficiency of this device is not as good as in the case of passenger cars. This is probably due, in some cases, to a compromise between emission reduction and acceleration performance which is important for sporty motorcycles. In other cases it is clear that the emission control strategy has not been completely optimized yet. Finally looking at CO2 (Figure 39) mopeds have in general lower emission than 4-stroke engines. Another big difference between two-stroke engines and four-stroke engines is the fuel. In two-stroke engines the fuel is mixed with a variable amount of lubricating oil and this have an important consequence on emissions. In fact, two-stroke engines have significant emissions of particulate matter although its composition is completely different from particulates emitted by diesel vehicles. While in the latter case, particulates mainly consist of carbonaceous material (soot) and heavy volatile compounds adsorbed on soot particles, almost all the particulate matter from mopeds consists of condensed heavy hydrocarbons coming from the incomplete combustion of the lubricant. Lubricants have very high boiling points (well above 350° C) and therefore are the most difficult to evaporate in the combustion chamber. As a consequence lubricant can generate some soot and can be also emitted at the tailpipe in the form of very small droplets.

As far as PM emissions are concerned, Figure 40 clearly shows that mopeds may have very high particulate emissions. However, it is also evident that advanced 2-stroke engines (MT006-2S-50) have very low PM emission. As a conclusion, it can be stated that the widespread adoption of four-stroke engines is not the panacea to reduce the impact of mopeds on air quality. Four-stroke engines have significant CO and HC emissions and NOx levels much higher than two-stroke engines. Emissions from four-stroke engines can be very effectively reduced by using the three way catalyst technology but this requires the implementation of other technologies such as electronic injection, electronic management system of the engine and oxygen sensors. These technologies increase the cost of the engine especially in the case of very small ones. While it makes sense to implement the catalytic converter technology in medium-large motorcycles, for small mopeds the adoption of improved/advanced two-stroke technology might result more cost-effective.

- 58 -

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HC

Em

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ons

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Driving cycles

2-stroke engines 4-stroke engines

Figure 36- Emissions of total hydrocarbons from mopeds (2-stoke engines) and motorcycles

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ons

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Figure 37- CO Emissions from mopeds (2-stoke engines) and motorcycles

Euro 2 mopeds

Euro 2 mopeds

- 59 -

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Figure 38- NOx emissions from mopeds (2-stoke engines) and motorcycles

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Figure 39- CO2 emissions from mopeds (2-stoke engines) and motorcycles

Euro 2 mopeds

Euro 2 mopeds

- 60 -

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PM e

mis

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s (g

/km

)

ECE47 HotECE47 Cold6 UDC6 UDC+EUDC

Driving Cycles

2-stroke engines 4-stroke engines Figure 40- PM emissions from mopeds (2-stoke engines) and motorcycles

Once the filters were weighted for PM (total mass) they were reserved for chemical analysis of their content on some significat PAH compounds. Laboratory received two filters for each test performed: first and second phases of the ECE-47 cycle. The first part of the cycle is commonly associated to the cold part of the test when the mopeds tend to emit more PM and consequently PAH content is higher for pre-Euro 1 moped and moped provided with oxy-cat. The moped with injection technology behaves in the opposite way. We will show below the results corresponding to the sum of 8 of all PAH which are common compouds found in all mopeds and motorcycles. All results have been expressed µg/km. Taking into consideration that mopeds and motorcycles are anyway driven in a different way in the real world, the results for this type of vehicles are shown in the same graph (Figure 41) even if the legislative cycle for mopeds is different from the driving cycle prescribed for motorcycles. The differences between mopeds emissions can be even of 90% in the cold phase depending on the technology and emissions standard. Graphs clearly show that all 2-stroke engines have higher PAH emission than 4-stroke engines and consequently, they also show higher TEQ values. The discharge of fresh mixture during the scavenging phase of conventional 2-stroke engines may be the main reason not only for high hydrocarbon emissions but also for the high content of PAHs in the PM. Same as we obserbed before for the other pollutants, 4-stroke engines produce a less noxious exhaust than 2-stroke engines when refeering to PAHs. Of course, if the motorcycle is equipped with a three way catalyst, all the emission are greatly reduced and may reach the typical levels of catalysed passenger cars. However, tests performed on motorcycles equipped with a catalytic converter have shown that often the efficiency of this device is not as good as in the case of passenger cars.

Euro 2 mopeds

- 61 -

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8 PAH [µg/km] ECE47 HotECE47 ColdECE6ECE6+EUDC

Figure 41- PAH emissions from mopeds (2-stoke engines) and motorcycles

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Figure 42- B[a]Py emissions from mopeds (2-stoke engines) and motorcycles

Euro 2 mopeds

Euro 2 mopeds

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ECE47 HotECE47 ColdECE6ECE6+EUDC

Figure 43-TEQ emissions from mopeds (2-stoke engines) and motorcycles

Figure 44 shows the results of the speciation for PAH compounds of the PM collected for the 3 mopeds tested in our laboratory. The most volatile of these 16 EPA priority PAHs were not quantified in the present study since these compounds display a low recovery in our analytical procedure and are expected to partition mainly into the gas-phase of the exhaust. The emission factors for the sum of PAHs of 2-stroker motorbikes running under the ECE 47 cycle (quantified in μg PAH / km) vary as showed in Figure 44. The mass of PAHs emitted per km can be calculated just by means of the same formula used to calculate the particulate total mass.

Category Motorcycles Eng. (cc) 2S 4S

Engine/After-treatment

Moped Pre-Euro1 (MT001) 50 X Standard 2-stroke engine Moped DI (MT002) 50 X Ditech Engine, Direct injection

Moped Oxycat (MT003) 50 X Moped, With Catalyst

Euro 2 mopeds

- 63 -

0,010,020,030,040,050,060,070,080,0

Pre-Euro1

DI Oxycat

μg/

Km

Benzo(ghi)perylene

Dibenzo(ah)anthracene

Indeno(123cd)pyrene

Benzo(a)pyrene

Benzo(k)fluoranthene

Benzo(b)fluoranthene

Chrysene

Benzo(a)anthracene

Pyrene

Fluoranthene

Figure 44- PAH distribution for individual components in PM from 2-stroke motorcycles running the

ECE_47 cycle: Effect of diverse technologies on PAHs emissions from three different mopeds

The concentration of the individual PAHs varied from 10 to 68 µg PAH/km, with the highest values found for the Pre-EURO 1 moped with standard 2-stroke engine and no after treatment. The most abundant compounds present in the PM from Pre-Euro 2 moped and the oxy-cat moped were fluoranthene and pyrene which result to be less toxic. Of particular interest is to note that almost six to seven times lower PAH emission were obtained for the moped with direct injection as compared to the PAH emitted by the mopeds with carburetor, with or without after treatment.

It is very significant the fact that emissions for the cold phase of the ECE_47 cycle are always higher than in the second part of the cycle. This effect could not be appreciated for the DI moped.

When the results are presented as B(a)P toxicity equivalent we can observe same pattern as shown for the total concentration of PAH (Figure 45). The B(a)P toxicity equivalent emission TEQ associated to particle-bound PAHs in the particulate emitted by the three mopeds varied in a broad range from approximately 1 µg TEQ/km of both phases of the cleanest moped with direct injection to almost 8µg TEQ/km for phase one of the moped with oxy-cat.

TEQ values for the different test followed the same trend as PAH values for pre-euro 1 moped and the DI moped. It is necessary to remark that the values for the moped provided with oxi-cat the TEQ values are now the highest. This is not an unexpected result since this effect have been previously reported.

These emissions factors are much over the levels previously found in our laboratories for EURO 3 Diesel LD vehicles.

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0,0

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5,0

6,0

7,0

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Pre-Euro 1 Phase1&2 DI Phase1&2 Oxycat Phase1&2

μg

TEQ

/Km

Figure 45 - Variation of B(a)P toxicity equivalent emissions (TEQ) from 2-stroke motorcycles running the ECE_47 cycle: Effect of two different oils on the total emission of toxic PAH

- 65 -

4. EFFECT OF LUBRICANT QUALITY AND USE OF GASOEUS FUEL (LPG) ON EXHAUST EMISSIONS FROM MOPEDS

4.1 Experimental work

4.1.1 Test fleet The test fleet consisted of 4 mopeds equipped with a two strokes engine but differing for the engine technology (carburettor or fuel injection) and the presence or not of an aftertreatment device. The test fleet is described here below (table 5.1): Table 5.1

Category Motorcycles Displacement (cc) Main Features

Moped MT001-M-50 50 Standard 2-stroke engine Moped MT002-M-50 50 Direct Injection Engine, EFI Moped MT003-M-50 50 2-stroke + Oxidation Catalyst

Moped MT004-M-50 50 2-stroke + Oxidation Catalyst + LPG conversion kit

EFI = Electronic Injection

4.1.2 Test lubricants In order to have an understanding about the effect of lubricating oil quality on pollutant emissions from mopeds and especially on particulates, two different lubricants were tested (Table 5.2). Table 5.2: Test lubricants

Lubricant Type Specifications Low Quality Mineral API TC

High Quality Full synthetic API TC, JASO FC, ISO-L-EGD

- The first one was a cheap low quality lubricant having low-medium performances. It was a mineral oil with a limited content of additives (anti-wear, detergent, dispersant, etc.). It met the API TC specifications. - The second test lubricant was a top quality lubricant, full synthetic and with a high content of additives ensuring a high performance level. It met the following specifications: API TC, JASO FC and ISO-L-EGD.

4.1.3 Test fuel The same reference gasoline (CEC RF-02-99) was used for all the emission tests. The moped equipped with the LPG conversion kit was tested with a commercial LPG from a normal refuelling station.

- 66 -

4.1.4 Emission tests The emission tests were carried out according to the current legislative driving cycle for mopeds (ECE 47). This cycle consists of eight repetitions of a base driving cycle as shown in figure 1. The legislation prescribes that emissions from mopeds have to be measured only over the last four repetitions (Hot Part 5-6-7-8) while, during the first four repetitions (Cold Part 1-2-3-4) the exhaust gas does not have to be sampled. However, in this experimental programme the emissions were measured also during the cold part of the cycle and therefore for each pollutant and for each ECE 47 test two different values (the first one referred to the cold part of the cycle and the second one to the hot part) are available. Since particulate emissions from mopeds are not currently regulated there is no legislativr procedure to measure them; therefore the procedure prescribed for diesel vehicles was used as described in the chapter 2.4.1.

4.2 Particulate emissions characterisation The only pollutant emissions from moped currently regulated are the gaseous ones (HC, CO, NOx); there is no emission standard for particulates and that means that there is no regulated procedure to measure particulate emissions from these vehicles. In this experimental programme it was decided to measure particulate matter emissions using the current regulated procedure prescribed for Diesel vehicles. The total mass of particulates emitted by a diesel vehicle is measured using a dilution tunnel and CVS (Constant Volume Sampling) system. The diluted exhaust gases are sampled by means of an isokinetic probe and are then forced to pass through a Teflon coated glass fiber filter kept at a temperature that must be below 52 °C and at a pressure close to ambient pressure; particulates can be defined as all the material that is collected on the filter at these conditions. In order to avoid contaminating the sampling line and the instrumentation with very large droplets of lubricant emitted by the mopeds, the legislative procedure for Diesel vehicles was modified inserting a cyclone between the exhaust tailpipe and the transfer line connected to the dilution tunnel. The cyclone used is shown in Figure 46.

- 67 -

Figure 46: cyclone used for emission tests with mopeds

The experimental programme was designed to investigate not only the effects of lubricant quality and fuel on particulate total mass but also to investigate the effects on other physical characteristics:

Mass/size distribution, measured by means of a Low Pressure Impactor with 12 stages. From the measurement performed with the LPI it is also possible to calculate the particulate total mass by adding up the particulate mass collected on each impactor stage. The LPI used in this experimental programme has the following main features: - Manufacturer: Hauke GmbH - 12 stages - Volume flow rate: 25 l/min - Measuring range: 0.0085 μm-16 μm (aerodynamic diameter)

Before starting the measurements, the LPI is disassembled and a previously weighed aluminium foil with a suitable shape is placed on the plate of each stage. Once the LPI has been assembled again, it is connected to an isokinetic sampling probe located on the dilution tunnel and to a suction pump. After the test, each aluminium foil is weighed again to measure the mass of the particulates collected on it. To avoid condensation of water vapour the impactors were heated up at 50 °C with a heating jacket. • Number/size distribution at constant speed (TSI SMPS, model 3080). The number/size distribution at constant speed of the particles emitted was measured using a TSI Scanning Mobility Particle Sizer (SMPS). It consists of an electrostatic classifier (DMA column) and a condensation particle counter. The principle of operation of the electrostatic classifier is the following: polydisperse submicrometer aerosol passes through a radioactive bipolar charger that establishes a bipolar equilibrium charge level on the particles. Then the particles enter into the differential mobility analyser (DMA) and are separated according to their electrical mobility; this parameter is inversely

- 68 -

related to particle size. A monodisperse aerosol exits the electrostatic classifier and the particle concentration is measured by means of the condensation particle counter. Changing the voltage of the DMA it is possible to select different size classes and therefore it is possible to measure the particle size distribution. The SMPS can be operated in the single size mode or in the scan mode; in the single size mode the voltage of the DMA is set to a fixed value and in this way it is possible to measure, on line, the concentration of particle having a chosen size. In the scan mode, the voltage of the DMA is instead continuously changed from a voltage value to another voltage value that corresponds to two different electrical mobility diameters; in such way, it is possible to measure the number/size distribution of the particles having a diameter falling in that range. Since a single scan takes at least 60 seconds, particle size distribution in terms of particle number can be measured only at steady state conditions.

- 69 -

4.3 Instrumentation details Regulated pollutant emissions were measured using a chassis dyno and a conventional CVS system with a critical flow Venturi; the CVS is equipped with four critical orifices that allow to select the most appropriate flow rate from a minimum of 1.5 m3/min to a maximum of 11.25 m3/min. The roller bench of the chassis dyno was a single roller type manufactured by Zoellner GmbH suitable for testing small two wheelers:

- Diameter: 48” - Inertia range: 150-3500 kg - Maximum speed: 200 km/h

To follow the legislative cycle, the driver was assisted by a driver aid system. Emission measurements were performed using the following analysers: • CO: Hartmann & Braun IR analyser. • NOx: Hartmann & Braun chemiluminescence analyser. • HC: Hartmann & Braun FID analyser. • Particulate mass: particulate samples were collected according to the legislative procedure for

Diesel vehicles using Pallflex EMFAB TX40HI20 filters and the mass was determined by weighing.

4.4 Results

4.4.1 Effect of lubricant quality

4.4.1.1 Particulate total mass Before investigating the effect of the selected test lubricants on the emissions, some tests were performed with the mopeds in the same conditions as they had been delivered to the JRC. In particular these tests were carried out using the lubricant that was originally in the mopeds (hereinafter called “factory lubricant”). Then, at least two emission tests were carried out for each moped and for each test lubricant; in all the tests particulate total mass was measured both over the cold part and over the hot part of the ECE 47 cycle using the regulated procedure prescribed for diesel vehicles. The results of the particulate total mass measurements are reported in Figure 47. The effect of the lubricant quality on particulate total mass in terms of percentage variations are calculated considering the emission values referred to the whole ECE 47 cycle.

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Effect of Lubricating Oil Quality on Moped Emissions ECE 47 Cycle - Particulates Emissions

0.000

0.050

0.100

0.150

0.200

0.250

MT001-M-50 MT002-M-50 MT003-M-50 MT001-M-50 MT002-M-50 MT003-M-50

Tota

l Mas

s (g

/km

)

Low Quality LubricantHigh Quality LubricantFactory Lubricant

ECE 47 Cold Part (1-2-3-4) ECE 47 Hot Part (5-6-7-8)

Figure 47: particulate total mass measured over the ECE 47 cycle – effect of lubricant quality. (Average of min. 2 tests)

Figure 48: particulate total mass measured over the ECE 47 cycle – effect of lubricant quality

(percentage variation). (Average of min. 2 tests)

Effect of Lubricating Oil Quality on Moped Emissions ECE 47 Cycle (Cold Part + Hot Part) - Particulates Emissions

0.000

0.050

0.100

0.150

0.200

0.250

MT001-M-50 MT002-M-50 MT003-M-50

Tota

l Mas

s, (g

/km

)

Low Quality LubricantHigh Quality Lubricant

-24%

+17%

-38%

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The effect of the lubricant quality resulted to be more than significant for two of the three mopeds tested: for the mopeds MT001-M-50 and MT003-M-50 an important decrease of particulate emissions was in fact detected in both the cold and hot parts of the cycle. The lubricant that was originally in these two mopeds gave intermediate emission levels compared to the two test lubricants. The effect of the lubricant was completely different in the case of the moped MT002-M-50, the one equipped with the direct injection engine: the effect was smaller and, moreover, it went in the opposite direction compared to the other two mopeds equipped with conventional two stroke engines. In fact particulate emissions from moped MT002-M-50 increased with the high quality lubricant and the highest emissions were noticed with the factory lubricant. Figure 5.2 puts also in evidence another difference between the moped MT002-M-50 and the other ones. While for mopeds MT001-M-50 and MT003-M-50 the particulate total mass determined over the hot part of the driving cycle was lower than the mass measured over the cold part, the moped MT002-M-50 exhibited higher particulate levels over the hot part. The different behaviour of the moped MT002-M-50 is surely linked to the direct injection technology and in particular to the different lubrication system. In conventional two stroke engines the lubricant enter into the combustion chamber mixed with the fuel, whereas in the tested direct injection engine the lubricant drips into the air inlet duct and enter into the combustion chamber mixed only with air.

4.4.1.2 Mass/size distribution As described, the mass-size distribution of the particles emitted by the mopeds was measured over the ECE 47 cycle with a Low Pressure Impactor (LPI). The results of the measurements performed with the LPI are in very good agreement with those obtained with the filter method. In the case of mopeds MT001-M-50 and MT003-M-50 the mass/size distributions showed a decrease of the mass of particulates emitted with the high quality lubricant (Figure 49 to Figure 51) as already noticed for the total mass measured with the filter; also for the moped MT002-M-50 the increase of particulate emissions was confirmed by the LPI result. The effect of lubricant quality on the shape of the mass/size distribution seems to be not significant; in fact, although the particulate emissions are lower in terms of mass, the mass/size distribution obtained with the high quality lubricant is very similar to the one obtained with the low quality lubricant. The results of the measurements performed with the LPI have been cross-checked with those obtained with the filter by comparing the total mass values. In the case of the LPI the particulate total mass has been calculated adding up the mass collected on each stage of the impactor. The plot (Figure 52) shows that the total mass measured with the LPI is always lower than the corresponding filter value and that the former ranges from 86% to 98% of the latter. This result is typical and it is probably due to losses of volatile material that occur in the impactor where, especially in the last stages, the pressure is very low. Moreover, it has to be taken into account that there was not a filter downstream the impactor to recover material not deposited on the impactor stages. Despite of these differences, the results are in very good agreement and the trends of the particulate emissions in response to the change of lubricant are exactly the same.

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Figure 49: mass/size distribution – effect of lubricant quality (Average of min. 2 tests)


Effect of Lubricating Oil on Particulate EmissionsECE 47 Cycle - Particulate Mass/Size Distribution (LPI 11 stages)

0.00E+00

2.00E-02

4.00E-02

6.00E-02

8.00E-02

1.00E-01

1.20E-01

10 100 1000 10000 100000Aerodynamic Diameter (nm)

dM/d

LogD

(g/k

m)


MT001-M-50 (Pre - Euro 1)


0.00E+00

1.00E-03

2.00E-03

3.00E-03

4.00E-03

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dM/d

LogD

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m)


MT002-M-50 (Euro 1 - Direct Inj.)

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dM/d

LogD

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m)


MT003-M-50 (Euro 1 - Oxycat)


Particulate Emissions from MopedsTotal Mass - Filter vs LPI

0.000

0.050

0.100

0.150

0.200

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MT001-M-50 MT002-M-50 MT003-M-50 MT001-M-50 MT002-M-50 MT003-M-50

Tota

l Mas

s, (g

/km

)

FilterLPI

Low Quality Oil High Quality Oil91%

97%

95%88%

86%

98%

Figure 52: particulate total mass-comparison between LPI and filter results (Average of min. 2 tests)

4.4.1.3 Number/size distribution (steady state conditions) The number/size distributions of the particles emitted by the test mopeds were measured only at a constant speed of 40 km/h; in fact it is not possible to perform measurements in transient conditions with the SMPS as it takes at least 60 seconds to complete one scan. The measurements were performed at 40 km/h; this speed had been chosen because it is close to the maximum speed allowed for mopeds (45 km/h).

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Like the mass, also the particle number and size were influenced by the lubricant quality; the effect of the lubricant resulted to be dependent on the engine technology. The number of particles, especially of the large ones, emitted by the pre-Euro 1 moped (MT001-M-50) considerably decreased (Figure 53) with the high quality lubricant. Moreover, the mean diameter of the distribution was slightly smaller than in the case of the low quality lubricant; this result is mainly due to reduction of the number of the large particles since the number of fine particles emitted did not change significantly.

Figure 53: number/size distribution – effect of lubricant quality (Average of 5 consecutive scans)

The size distribution and the number of the particles emitted by the moped MT002-M-50 were instead not significantly affected by the lubricant quality. Nevertheless the small increase of the particle number detected with the high quality lubricant is consistent with the effects noticed on the mass (slight increase of particulate emissions). On the contrary, in the case of the moped MT003-M-50 (Figure 55) the effect of lubricant quality on the number/size distribution resulted to be not consistent with the effects on the mass. In fact the particle number increased with the high quality lubricant while particulate mass was reduced by it; moreover, the mean diameter of the particles became smaller. This result is in contrast with the results obtained with the LPI that did not show any change of the mass/size distribution shape. To this respect it has to be taken into consideration that the SMPS measurements were performed at constant speed while the mass measurements were carried out over the ECE 47 cycle. Moreover the repeatability for moped MT003-M-50 was not as good as for the other two mopeds and therefore that result could be even an artefact.

Effect Of Lubricating Oil on Particulate Emissions Number/Size Distribution - Constant Speed: 40 km/h

0

2E+13

4E+13

6E+13

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1E+14

1.2E+14

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[dN

/dlo

g D

p]/k

m

Low Quality OilHigh Quality Oil

MT001-M-50 (Pre - Euro 1)

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0

5E+12

1E+13

2E+13

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/dlo

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m


MT003-M-50 (Euro 1 - Oxycat)


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4.4.2 Effect of lubricant quality on gaseous emissions As shown in the figures Figure 56 and Figure 57, particulate emissions were those more affected by the lubricant quality. The effect on gaseous pollutants was less important and in most of the cases not significant; anyway a reduction trend was noticed for HC, CO and NOx emissions.

Effect of Lubricant Oil Quality on Moped EmissionsECE 47 Cycle (Cold Part) - Percentage Variations Change from Base Quality Oil to Top Quality Oil

-3%

-13%

-6%

-3%

-9%-11%

0%

-8%

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-3%

-25%

-20%

14%

-33%

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-10%

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10%

20%

MT001-M-50 (2 Strokes - No Cat) MT002-M-50 (2 Strokes - Injection) MT003-M-50 (2 Strokes - Oxycat)

HC

CO

CO2

NOx

PM

Figure 56: gaseous and particulate emissions-effect of lubricant

Effect of Lubricant Oil Quality on Moped EmissionsECE 47 Cycle (Hot Part) - Percentage Variations

Change from Low Quality Oil to High Quality Oil

-2%-5% -6%

-2% -4%

-18%

-1%

-6%

1%

-3%

-9%

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-30%

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-10%

0%

10%

20%

30%

MT001-M-50 MT002-M-50 MT003-M-50

HCCOCO2NOxPM

Figure 57: gaseous and particulate emissions – effect of lubricant quality

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The growing concern about potential health effects of particulate matter (PM) differences associated to the oil quality necessitates improved knowledge on the physical characteristics of PM but not only. We have also analyzed its content on PAH compounds.

Two-stroke motorcycles run with a mixture of gasoline and lubricant causing emission of unburned oil. These circumstances cause a great effect in the quality of the particulate emitted and so in the content of potential toxic compounds. In order to asses the effect of two different oils on the PAH emissions from a pre-Euro 1 moped, we analyze below the effect of a mineral and a synthetic one on the total production of toxic PAH. The pre-Euro 1 moped is the same we have been testing in previous experiments.

Total particulate mass collected using Pallflex 70 mm T60A20 filters generally consist of agglomerates of very small carbon particles (soot fraction) and heavy hydrocarbons adsorbed on them (soluble organic fraction). Chemical composition of the soluble organic fraction is important due to its relevance for human health. In particular, what is grabbing our attention is the amount of potentially harmful organic compounds adsorbed on the particles which very much depend on the quality of the oil mixed with the fuel. Data presented here demonstrate the potential for reducing the possible toxicity of the PM emissions from existing mopeds by optimizing the two-stroke oil quality.

In Figure 58 we can appreciate that non significant difference in total PAH distribution is observed when using the same mineral oil either if we performed the test with cold CVS or we heated it. It is well known that heavy HC from unburned oil could condense al along the exhaust system and collection device so this experiment was designed to find out if the effect is significant on the emissions.

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Mineral oil cold Mineral oil hot Synthetic oil

Benzo(ghi)pyrelene

Dibenzo(ah)anthracene

Indeno(123cd)ptyrene

Benzo(a)pyrene

Benzo(k)fluoranthene

Benzo(b)fluoranthene

Benzo(a)anthracene

Chrysene

Pyrene

Fluoranthene

Figure 58: PAH emitted by Pre-EURO1 moped tested with two different oils: mineral and synthetic. When we express these results in terms of TEQ/km we can appreciate that CVS cold or hot does not make a noteworthy difference. The two compounds that are contributing more to the TEQ are benzo(a)pyrene and dibenzo(a,h)anthracene. The use of a better quality mineral oil with a low content in aromatics leads to a notable decrease of the toxicity equivalent of the particulate emitted.

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0,0

2,0

4,0

6,0

8,0

10,0

12,0

14,0

Mineral oil CVS cold

Mineral oil CVS hot Synthetic oil

ug B

(a)P

TEQ

/km

Figure 59: Variation of B(a)P toxicity equivalent emissions when two oils are compared.

4.4.3 Tests on a moped converted to LGP fuel One possibility to reduce emissions investigated by the JRC is to use a LPG conversion kit for mopeds. The tests have been carried out according to the protocol described in section 5.1 on a prototype. The moped has been tested in two configurations:

• Running on gasoline • Running on LPG

The emissions obtained in the two configurations are shown in Figure 5.13. While the use of LPG results in important reductions of PM and HC emissions, NOx are greatly increased (up to +300%). Nevertheless, due to the very low NOx levels of the moped running on gasoline, the emissions are still lower than four-stroke engines.

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Moped M-50-004 (2 strokes) - Effect on Emissions of Conversion to LPG ECE 47 Cycle - Percentage Variations

-37%

-90%

9%

241%

-85%

-43%

-90%

9%

318%

-49%

-150%

-100%

-50%

0%

50%

100%

150%

200%

250%

300%

350%

HC CO CO2 NOx PM

Cold Part (1-2-3-4)Hot Part (5-6-7-8)

Figure 60: effects on emissions of a moped running on LPG compared to gasoline

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4.5 Conclusions The next stricter emission standards for mopeds will bring important benefits only in the mid/long-term, when a significant fraction of the fleet will have been replaced by newer vehicles. Nevertheless there are some measures that can be adopted to reduce emissions from the existing mopeds. Throughout the testing programme on mopeds conducted at the JRC, engine settings and maintenance resulted to affect emissions to a large extent. This means that an inspection and maintenance programme for mopeds can be very effective in reducing emissions. In addition, it is well known that most of mopeds are modified in order to remove the speed limiting device and this has a huge effect on emissions. Anti-tampering measures should put in place in order to deter people from this practice. Moreover, other tests carried out at the JRC have shown that a high quality lubricant (e.g. full-synthetic) can reduce PM emissions up to 62% and, to a lower extent, gaseous emissions. The use of conversion kits to convert mopeds to LPG is another possible option to reduce HV and PM emissions. However, when properly set, the engine shows an increase of NOx emission as a drawback. Finally, other works performed in collaboration with the Swiss network BAFU [2] have found that other aspects are important to control emissions from mopeds:

• Lower oil dosing • Supplementary filtration and oxidation devices (wire-mesh filter catalyst) • Higher quality fuels

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5. REFERENCES

1. Jia, L.-W.; Shen, M.-Q.; Wang, J., Lin, M.Q.; “Influence of Ethanol-gasoline blended fuel on emission characteristics from a four –stroke motorcycle engine”, Journal of Hazardous Materials A 123 (2005) 29-34; Leong, S. T.; Muttamare, S.; Laortanakul, P.; “Influence of benzene emissions from motorcycles on Bangkok air quality”, Atmos. Environ. 36 (2002) 651-661. 2. Czerwinski, J.; Comte, P.; Astorga, C.; Rey, M.; Mayer, M.; Reutimann, F.; “(Nano) Particles from 2-S Scooters: SOF / INSOF; improvements of aftertreatment; toxicity”, (2007) SAE Technical Paper 2007-01-1089. 3. Dong, M.; Locke, D. C.; “High pressure liquid chromatographic method for routine analysis of major parent polycyclic aromatic hydrocarbons in suspended particulate matter”, Anal. Chem., 48 (1976) 2, 368-371. 4. Allen, J. O.; Dookeran, N. M.; “Measurement of Polycyclic Aromatic Hydrocarbons Associated with Size-Segregated Atmospheric Aerosols in Massachusetts”. Environ. Sci. Technol., 30 (1996) 3, 1023-1031. 5. EPA. “Provisional guidance for Quantitative Risk Assessment of Polycyclic Aromatic Hydrocarbons”. U.S. Environmental Protection Agency, Washington (1989). 6. EEA Report, No. 8/2006 (ISSN 1725-9177) “Energy and environment in the European Union: Tracking a process to integration. (2006) 7. Latella, A.; Stani, G.; Cobelli, L.; Duane, M.; Junninen, H.; Astorga, C.; Larsen, B.R.; “Semicontinuous GC analysis and receptor modeling for source apportionment of ozone precursor hydrocarbons in Bresso, Milan, 2003”, J. Chromatogr. A 1071 (2005) 29-39. 8. Barbusse, S. and Ducreux, B.-O.; “Motorcycles and Mopeds – Energy and the Environment”. ADEME Report, French Environmental and Energy Management Agency, Transport Technology Department, Jan. 2006. 9. Vasic, A.M.; Weilenmann, M. “Comparison of Real-World Emissions from Two-Wheelers and Passenger Cars”. Environ. Sci. Technol. 40 (2006) 149-154. 10. Ntziachristos, L.; Mamakos, A.; Samaras, Z.; Xanthopoulos, A.; Iakovou, E. “Emission control options for power two-wheelers in Europe”. Atmos. Environ. 40 (2006) 4547-4561. 11. Tsai, J.-H.; Chiang, H.-L.; Hsu, Y.-C.; Weng, H.-C.; Yang, C.-Y.. “The speciation of volatile organic compounds (VOCs) from motorcycle engine exhaust at different driving modes”. Atmos. Environ. 37 (2003) 2485-2496. 12. Theloke, J.; Friedrich, R.; “Compilation of a database on the composition of anthropogenic VOC emissions for atmospheric modeling in Europe”. Atmos. Environ. 41 (2007) 4148-4160. 13. Srivastava, A. “Source apportionment of ambient VOCS in Mumbai city” Atmos. Environ. 38 (2004) 6829-6843. 14. Astorga, C.; Junninen, H.; Duane, M.; Manfredi, U.; Martini G.; Krasenbrink, A.; Larsen, B. “Potential Ozone Formation of C2-C9 Hydrocarbons emitted by mopeds, diesel and gasoline vehicles”. International Conference on Future Worldwide Emission Requirements for Passenger Cars

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and Light Duty Vehicles and EURO V, Milan, Italy, Dec. 2003, book of abstracts, pp. 85 (also available at http://ies.jrc.cec.eu.int/Units/eh/events/EURO5/, last consulted 31st March 2008). 15. EPA – Carcinogenic effects of Benzene: An updated toxicological review of benzene, EPA/600/P-97/001F April 1998 (CAS No. 71-43-2). 16. EPA – Health Assessment of 1,3-butadiene - EPA/600/P-98/001F (October 2002). 17. Andersson, J. D.; Lance, D. L.; Jemma, C.A.; “DfT Motorcycle Emissions Measurement Programmes: Unregulated Emissions Results”. (2003) SAE Technical Paper No. 2003 0335. 18. W.P.L. Carter “Development of ozone reactivity scales for volatile organic compounds”. J. Air Waste Manage. Assoc., 44 (1994) 881-899. 19. Rembges, D, Fantecchi, G., Dutaur, L. and Brun, C., (1999) « AIRMON Annual Report, European Commission, EUR 19665 EN » 20. Machado Correa, S.; Arbilla G.; “Carbonyl emissions in diesel and biodiesel exhaust” Atmospheric environment, 42 (2008) 769-775.

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European Commission EUR 23999 EN – Joint Research Centre – Institute for Environment and Sustainability Title: Physical & Chemical Characterization of emissions from 2-Stroke Motorcycles (Comparison with 4-stroke engines) Author(s): G. Martini, C. Astorga, T. Adam, P. Bonnel, A. Farfaletti, H. Junninen, U. Manfredi, L. Montero, A. Müller, A. Krasenbrink, B. Larsen, M. Rey and G. De Santi Luxembourg: Office for Official Publications of the European Communities 2009 – 83 pp. – 21 x 29.7 cm EUR – Scientific and Technical Research series – ISSN 1018-5593 ISBN 978-92-79-13540-8 DOI 10.2788/38196 Abstract Due to the significant emission reduction from light and heavy duty vehicles in the past few years, it came out that two-stroke engines are a considerably strong source of pollution in the urban areas where congested traffic made of these vehicles an appropriate alternative to increase mobility. After the entry into force of additional measures on light-duty vehicles (Euro 5/6) and on heavy duty vehicles (Euro VI), the share of two- and three-wheelers in total emissions should increase, in particular they may become higher contributors to gaseous emissions. In this context, the Commission wishes to prepare a recast of the legislation on the type-approval of two- and three-wheelers as well new measures on safety and pollutant emissions to be proposed by mid 2009. In view of this new legislative process and the preparation of an amendment to the European directives 97/24/EC and 2002/51/EC5 on “characteristics of two or three-wheel motor vehicles”, Transport and Air Quality Unit has worked on the characterization of emissions from motorcycles with the aim of obtaining estimates of the impact of these emission sources on air quality. In this research program, we have taken into consideration some measures that can be adopted to reduce emissions from the existing mopeds, considering that the next stricter emission standards for mopeds will bring important benefits only in the mid/long-term, when a significant fraction of the fleet will have been replaced by newer vehicles. Indeed, new available after-treatment technologies may reduce emissions from Euro 1, two-Stroke motorcycles by a factor of 10 compared to previous emissions standard. Some of these new technologies for emission reduction are still under development and they are expected to be ready to allow new emission limits in the next legislative proposal. This project also showed the influence of the engine technology and running conditions on the emissions for regulated pollutants as well as for some non-regulated ones (ie. PM, CO2, PAHs, VOCs, Carbonyls). Throughout the testing programme on mopeds, engine settings and maintenance resulted to affect emissions to a large extent. This means that an inspection and maintenance programme for mopeds can be very effective in reducing emissions. Anti-tampering measures should put in place in order to prevent people from this practice.

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