6. Emission Legislation & Aftertreatment Devices

8/12/2019 6. Emission Legislation & Aftertreatment Devices

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EMISSION LEGISLATION&

AFTER-TREATMENT DEVICES

Dr. K. C. Vora

Head, ARAI Academy

The Automotive Research Association of India, Pune


2/73

RED BLOOD CELLS EXPOSED TO PARTICLES

1 m particles 0.078 m particles

Smaller particles are more dangerous


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EMISSION ROAD MAP FOR INDIA

Introduction of CO & HCPUC all over the country

Bharat Satage I for Metros

13 mode Diesel Emission > 3.5 T GVW

CO, HC & NOx for gasoline &

diesel vehiclesEvaporative emissions and cold start

for petrol < 3.5 T GVW.

Catalytic converters for gasoline cars

in Metros

Tractor emission norms

Durability of Catalytic Converter

Gen. Sets emission norms

CNG, LPG emission revision

PUC revision for 2/3 wheelers,

cars & CVs

Bharat Stage I for 2/3 wheelers

Bharat Stage I for 4 wheeler in India

Bharat Stage II for 4 wheeler in

Metros

Bharat stage II for 2/3 wheelersin India

Bharat Stage II for 4 wheelers in

India

Bharat Stage III for 4 wheeler in

11 select cities

Bharat stage III for 2/3 wheelersin India

Bharat Stage III for 4 wheelers

in India

Bharat Stage IV for 4 wheeler in

11 select cities

Before 2000 2000-2004 2005 onwards


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VEHICLE EMISSION NORMS & SULPHUR REDUCTION

SCHEDULE IN INDIA


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Source: CAI-Asia

FUEL SULPHUR LEVEL IN EUROPE (PPM)

0

100

200

300

400

500

Gasoline Diesel

Euro 2 Euro 3 Euro 4 Euro 5

Ref: M. Walsh, Clean Fuels in China (June, 2003)

India Cities 2005: 350 PPMIndia Cities 2010: 50 PPM

Fuel Quality (Sulphur Level) is critical for controlling Emissions


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FUTURE GASOLINE EMISSIONS STANDARDS - COMPARISON


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INDIAN EMISSION NORMS FOR 2 WHEELERS

-For Ref. Mass 170 kg ; * Only for HC

CO HC+NOx

14.25

8.5*

4.53.6

2.0 2.0 1.5 1.51.0 1.0

0

2

4

6

8

10

12

1416

Year

1991- 1996 2000 2005 2010

Emissio

nsg/km)


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INDIAN EMISSION NORMS FOR 3 WHEELERS - PETROL

30

12*

6.755.4

4

2 2.25 2.251.25

1.25

0

5

10

15

20

25

30

Emissions

,g/km

1991- 1996 2000 2005 2010

CO HC+Nox

-For Ref. Mass 170 kg ; * Only for HC;


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INDIAN EMISSION NORMS FOR 3 WHEELER - DIESEL

0.51

2.72

5

30

0.5

0.850.972

12*

0.14

0.1

0.05

0

5

10

15

20

25

30

35

1991- 1996 2000 2005 2010

Emissions,g/km

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

PM,g/k

m

CO HC+Nox PMFor RM of 350 kg

* Only for HC


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INDIAN EMISSION NORMS FOR PASSENGER CARS- PETROL

- For 1020 Rm < 1250 & For cc 1400 ; * Only for HC;

*

- ** **


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INDIAN EMISSION NORMS FOR PASSENGER CARS - DIESEL

- For 1020 Rm < 1250 ; * Only for HC ; ** M Category Vehicles

-

*

** **-

*


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DETERIORATION FACTORS IN INDIA

Category ofVehicles

Gasoline Diesel

CO 1.2 1.1

HC 1.2 NA

NOx 1.2 1.0HC+NOx N A 1.0

PM NA 1.2

Deterioration factors became applicable for gasoline

and diesel vehicles (fitted with catalytic converter)from 1stDecember 2002.

or

30,000 km Durability for 2-W & 3-W and

80,000km durability for four wheelers.


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INDIAN DRIVING CYCLE FOR 2 & 3 WHEELERS

0

10

20

30

40

50

0 20 40 60 80 100TIME(sec)

SPEED(km/hr)

Time DistanceAvg.

SpeedMax. Speed

Max.

accel.Max Decel

Idle time

ratio

Accel.

Time ratio

Decel time

ratio

Cruise

time

ratio

sec km km/h km/h m/s2 m/s3 % % % %

IDC

(6 Cycles)648 3.948 21.93 42 0.65 0.63 14.81 38.89 34.26 12.04


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BS III INDIAN DRIVING CYCLE FOR 4 WHEELERS

One Cycle of 195 sec

Part 1: 780 sec

Max Speed

90 KPH

Part 2:400 sec


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More stringent exhaust limits for Euro 3 and Euro 4

Separation of HC and NOx

Modified exhaust emissions test cycle

Deletion of first 40 s idle, start of bag sampling at

engine crank

Onboard diagnostics requirements for Gasoline andDiesel (derived from US OBD II, but without Evap-

monitoring).

With threshold values for fault storage and warning.

SALIENT FEATURES OF EURO III & EURO IV


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SALIENT FEATURES OF EURO III & EURO IV

Enhanced evaporative emissions requirements with new

24-hour diurnal test (temp profile 200C-350C)

Low temperature test for Gasoline vehicles

Measurement of HC and CO at -70

C during first 780seconds of revised urban and extra urban cycle

Reference fuel option with higher RVP and density

In-use durability requirements

Euro 3 : 80,000 km or 5 years.

Euro 4 : 100,000 km or 5 years


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New low temperature test at -7C

In-use conformity testing with durability distance of 100,000km for Euro 4

Revised evaporative emissions test

On-board diagnostics (OBD)

LIGHT-DUTY VEHICLES - EURO 3 AND CURRENT EURO 4


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** for GVW < 3500 kg & power < 85 kW * for GVW < 3500 kg & power > 85 kW or GVW>3500 Kg

for engines having swept vol. 3000 min-1

ESC: Euro Steady State Cycle, ELR: Euro Load Response, ETC: Euro Transient Cycle

NOx PM

9.0 0.4

7.0 0.15

9.0 0.4*

-- 0.68**

CH4 NOx PM

1.6 5.0 0.16

-- -- -- 0.13 -- -- -- -- -- 0.21

13 Mode Cycle

TA Limits in g/kwh COP Limits in g/kWh

CO HC NOx PM CO HC NOx PM

Euro I 4.5 1.1 8.0 0.36 4.9 1.23 9.0 0.4

Euro II 4.0 1.1 7.0 0.15 4.0 1.1 7.0 0.15

India2000

4.5 1.1 8.0 0.36* 4.9 1.23 9.0 0.4*

-- -- -- 0.61** -- -- -- 0.68**

ESC & ELR Tests ETC tests

Euro III CO HC NOx PM m-1

CO NMHC CH4 NOx PM

2.1 0.66 5.0 0.10 0.8 5.45 0.78 1.6 5.0 0.16

-- -- --0.13 -- -- -- -- --

0.21

COMPARISON OF EURO I, EURO II & EURO III STANDARDS

V/S INDIAN REGULATIONS (FOR HEAVY COMMERCIAL VEHICLES)


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HEAVY DUTY ENGINES- EURO 4/5 LIMITS (2005-2008)


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EURO 5 PROPOSAL


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EURO 5 PROPOSAL


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N2 CO2 H2O

NOX CO HC

Can

Mat

Ceramic Substrate with Catalytic Coating

3-WAY (TW) CATALYTIC CONVERTER

Catalytic converters transform NOx, CO & HC into N2, CO2& H2O


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CERAMIC SUBSTRATES - UNIQUE EXTRUSION PROCESS


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900/2 (Euro 4)400/6.5 (Euro 2)

AUTOMOTIVE SUBSTRATES ENABLING TECHNOLOGY

FOR ULTRA-LOW EMISSIONS


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GASOLINE EMISSIONS STANDARDS - COMPARISON

Achievable Today


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ADVANCES IN AUTOMOTIVE EXHAUST CATALYSIS

AIR-FUEL

MANAGEMENT

COLD-START

STRATEGIES

CATALYST

FORMULATION


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(Heywood)

Emission v/s Air Fuel Ratio


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Staying in the window


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Closed-loop Control with HEGO Sensor & Fuel Injection

(eastwood)


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Catalyst light-off (A/F 14.7)


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AIR-FUEL

MANAGEMENT

COMPLETED

COLD-START

STRATEGIES

CATALYST

FORMULATION


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Importance of Cold Start

Tailpipe HC Emissions (FTP Bag 1)

0

0.005

0.01

0.015

0.02

0.025

0 100 200 300 400 500

Time (s)

Tailpipe

HC

Mass(g

/s)

0

300

600

900

1200

1500

Temp

erature,(DegF)

XCatalyst "L ight-Off"

Temperature


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Trends of Catalytic Converter Configuration


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Advantages of Close Coupled Catalyst

(Umicore)


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Closed Couple Catalyst Design Criteria


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Position of Catalysts in the Exhaust System


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AIR-FUEL

MANAGEMENT

COMPLETED

COLD-START

STRATEGIES

COMPLETED

CATALYST

FORMULATION


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Characteristics of PGM Catalysts


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Improvement in Oxygen Storage Capacity


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Technology Options for a Sustainable Environmentally Friendly Mobility


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GASOLINE ENGINE TECHNOLOGIES

MPFI

precise control of fuel at all operating modes such asacceleration, idling, altitude, high and low temperatureoperation and enrichment based on load.

3-Way Catalytic Converter

Greatly reduces all three emissions of CO, HC and NOx

Close control of air fuel ratio is required through closeloop with lambda sensor

Variable Valve Timing - VVT

Improvement in fuel consumption

optimizes intake and exhaust valve actuation

added torque

reduces internal pumping losses

reduces production of the pollutant NoxEGRhelps to reduce NOx.

OBDhelps warning the user of malfunctioning of thesystem and its components.


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BSV ?

BSIV

BSIII

BSII

BSI

System Development

GASOLINE ENGINE TECHNOLOGY DEVELOPMENT

Fuel injection

3-W Catalytic converter

(pt/rh)

Fixed EGR

CNG / LPG

Fuel injection +

catalytic converter

(CC/UF)

Variable EGR

Variable valve timing

Multi valve

CNG / LPG

Direct in-cylinderinjection

Multi-brick catalytic

converter (CC+UF)

Lean burn, OBD

MPFI

PCV

O2 sensor

Knock Sensor

2-Way/ 3-Way Cat. Con.

Fuel Cells

Electric/Electric-

Hybrid


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NO+O2

NO2

NO3-

Pt Base metal

Catalyst Support

NOxHC, CO, H2

CO2, H2O, N2nitrate

Pt Base metal

Catalyst Support

Lean Operation

(NOx Trapping)

Rich Transient

(Reduce Stored NOx)

NO+O2

NO2

NO3-

Pt Base metal

Catalyst Support

NO+O2

NO2

NO3-

Pt Base metal

Catalyst Support

NOxHC, CO, H2

CO2, H2O, N2nitrate

Pt Base metal

Catalyst Support

NOxHC, CO, H2

CO2, H2O, N2nitrate

Pt Base metal

Catalyst Support

Lean Operation

(NOx Trapping)

Rich Transient

(Reduce Stored NOx)

TCICoffers a great advantage in

reducing emissions.Fuel Injection system holds the key tocombustion and emission optimization.Electronic control is more required tocontrol precise amount of fuel andinjection timing.

Cooled EGR is another way to reduceNOx but optimization is necessary.

After treatment devices such asoxidation catalysts and particulate trapsreduce tailpipe CO, HC and PM.

Sulphur reduction of fuel is essentialif aftertreatment devices are to be used

Lean Nox Trap and SCR are underdevelopment which help inreducingNox emissions

DIESEL ENGINE TECHNOLOGIES


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BSIV

BSIII

BSII

BSI

DIESEL ENGINE TECHNOLOGY DEVELOPMENT

Turbo charging

Inter cooling

(based on specific

power)

Moderate swirl

Injection pressure

> 800 bar

Rotary pump

VCO nozzle

EGR (need based)

Conversion to

CNG/ LPG

TC & inter coolingMulti valve

Low swirl

Injection pressure >

1200 bar

Unit injector / common

rail injection

Rotary pump and pilotinjection rate shaping

Variable geometry

turbocharger (VGT)

Oxycat

EGR (hot/cooled)

Electronic injection

control1

NOx Trap

Particulate trap

Common rail

injection

Injection

pressure > 1600

bar

On-board

diagnostic system

VGTCooled EGR

optimized ports,

combustionchambers

turbo charging

moderate to

high injection

pressures

(600800 bar)

Inline/rotary

BS V ?

Biodiesel/

Alcohol

blends?

aqueousurea

SCRcatalyst

HC, CO control NOx control

OxCat

CDPF

PM control

HC/CO/NH3 control

NOx sensor NOx sensorfeedbackfeedforward

deltaP

NO NO2

aqueousurea

SCRcatalyst


OxCat

CDPF

PM control

HC/CO/NH3 control


deltaP

aqueousurea

SCRcatalyst


OxCat

CDPF

PM control

HC/CO/NH3 control


deltaP

NO NO2

DOC/SCR/CDPF System

System Development


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KEY DRIVERS FOR CNG

Economy of operation

Reduction of harmfulemissions

PM emissions

Relevant to India wherediesel consumption is

five times the petrolconsumption

High safety, quieteroperation, less odor thandiesel

Regulatory imperatives

Supreme court directivecovering 11 cities

Gujarat Govt.:Ordinance forcompulsory use of CNG

Economy

2.841.7

8.56

0.99 0.6

5.97

1.011.69

0

2

4

6

8

10

4 wheelers (Cars) 3 wheelers

(Auto rickshaw)

Bus

Runn

ingCostinRs.

/km

Petrol CNG LPG

Emissions in g/km and % Reduction

2.4

21

0.4 8.9 0.38 0.0120

20

40

60

%reductionin

Emissions

diesel CNG

diesel 2.4 21 0.38

CNG 0.4 8.9 0.012

CO Nox PM

83% reduction 58% reduction 97% reduction

Source : Ernst and Young Pvt. Ltd.


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DIESEL EMISSION CONTROL

REQUIREMENTS DIESEL OXIDATIOCATALYST (DOC):

For CO & HC reduction. It does not alter NOx Reduce SOF portion of PM

It should not oxidize SO2to SO3

The catalysts such as the precious metals (Pt, Pd), which are active tooxidize the SOF are also active towards the oxidation of SO2to SO3.

Adding base metal Oxides (Vanadia) to high Pt loaded catalyst tosuppress the sulphate making reactions.

At low temperature SOF is adsorbed in pores & at high temperatureH2SO4is released. This is avoided with washcoat additives such assilica, zirconia, titania.


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NOx

P

critical

diesel

tuning

NOx / PM Trade-off


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NOx vs PM

Parameterchange Effect onNOx

Effect on PM

Cycle temperature

increases

There is excess air in

bowl

Longer premixed

combustion phase

Better

Combustion

conditionsprevails

Towardscompletecombustion

Improved initial

mixing, chances

of better

combustion


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A

B

C

D

EF

GH

50% 100%

50%

100%

P

NOx

A 2-V config

B 4-V config

C Increased inj. rate

D Inj. Timing retard

E Electronics in injection

F Variable swirl

G Oxicat, EGR

H DPF, DeNOx Cat

NOxPM Emission Control Strategy


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Particulate Matter (PM) Reduction


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Diesel Engine Euro III Technology Options


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Diesel Particulate Filter (DPF) Or Catalyzed Soot Filter (SCF)

Plugged channel honeycomb

Particulates trapped on wall

Regenerated to burn particles

Catalyzed or uncatalyzed


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Performance Requirements for DPF

Four basic requirements which DPF must meet:

adequate filtration efficiency to satisfy particulate

emissions legislation;

low pressure drop to minimize fuel penalty and

conserve engine power;

high thermal shock resistance to ensure filter

integrity during soot regeneration;

high surface area per unit volume for compact

packaging.


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DPF Regeneration


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Passive Regeneration


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Source: CAI-Asia

DPF Regeneration


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(Umicore)

Post Injection Regeneration for an Uncoated DPF


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Continuous Regenerative Trap (CRT)

Oxidises CO and HC to CO2 and H2O

NO is oxidised to NO2

Collects Soot in wall-flow particle filter

NO2 reacts with trapped soot to form CO2 & NO

Requirements: Fuel S < 50 ppm & NOx/PM > 20

Passive system - no external heating necessary

provided Temperature is high enough

(>260C for 40% of the time)

CO, HC, PM reduction > 90%


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CRT Particulate Filter

Inlet

Section

Catalyst

Section

Filter

Section

OutletSection

Honeycomb

Catalyst

Wall-flow

Filter


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NO2Reaction in a CRT

NO2

NO+CO2

NOO2

CO2COO2

H2O+CO2HCO2

Flow Through Catalyst Wall Flow Filter

NO+CO2

NO2


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HC De-Nox:

Fuel is injected downstream of catalyst which acts as a NOx

redundant. Operating temp. window 200 to 300 deg C.

NOx Adsorber ( Lean NOx Trap ):

Base metal Barium Alumina absorbs and stores NOx in lean

burn operation. Regeneration reqd to avoid deposition on

catalyst material. Occasionally rich mixture is fed which converts

adsorbed Nitrate into N2 .

Urea SCR:

Urea in solid or aqueous form is used. In the presence of

catalyst urea decomposes to produce NH3, which reacts with

NOx selectively. NH3 reacts with NO and NO2 converting to N2

molecules and H2O.

NOX CONVERTERS


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HC DeNOx Catalyst Or Diesel Lean NOx Catalyst (DLNC)

Reducing NOx by HC under the excess of oxygen is currently

the most advanced diesel DeNOx concept Zeolite absorbs HC during Cold Start and when the temp is

high enough for light-off, HC is released for reduction of NOx.

HC emissions are used to reduce NOx at around 300C

The catalyst for the HC DeNOx is Pt on support oxide

(Al2O3, SiO2,TiO2, ZrO2..)

This method requires reasonable amounts of HC in the exhaust

gas, which can be achieved, either by post injection using CRDi

or by secondary fuel injection.

NOx reduction up to 30% possible.

However, there is fuel penalty (3-6%) and expensive system

cost.


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HC DeNOx Mechanism

NO + O2= NO2

[NO activation, requires reducible site]

CxHy+ NO2= CO2 + N2 + H2O (Preferred)

[Competition for HC, on oxidizable sites]

CxHy+ O2=CO2+ H2O (Not preferred)[HC oxidation, very fast]


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NOx Adsorber Catalysts

Lean conditions (lambda > 1):

Oxidises CO and HC to CO2 and H2O

Oxidises NO to NO2

NO2 is stored as Nitrate

Rich conditions (lambda < 1):

Nitrates are reduced to NO2

NO2 is released and reduced to N2.

NOx reduction > 70% possible.

Requirements: S < 10 ppm


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NOx Adsorber Catalyst Functions

LEAN:

NO2generation

NO2storage

(CO, HC, VOF

oxidation)

RICH:

NOx release

NOx conversion

(Desulfation)


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Urea SCR

Within Europe, the principal NOx control strategystarting in 2005, is Selective Catalytic Reduction(SCR) using ammonia, derived from urea as thereductant.

Here ammonia reacts with NOx selectively on acatalyst, such as V2O5TiO2, under oxygen richexhaust gas

Urea/water solution reacts at > 200 Cto form NH3 and CO2.

NH3 reduces NO and NO2 to N2. NOx reduction > 80 % possible.

Fuel with S up to 500 ppm can be used.


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Urea SCR System Schematic

Oxidation

Catalyst

2 x SCR

Catalysts

Urea Injector

FLOW

1 x Pt Clean-up

Catalyst


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3000

Vehicle Weight (kg)

HC De-NOX

NOx adsorber

Urea SCR

20

202040

60

80

100

Euro-4 limit

Vehicle dependent Applicability of NOx Converters


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EMISSION CONTROL FOCUS ON PM + NOx


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DPF+SCR


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DPF+SCR+AMOX


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A Cleaner Future for India (Mobile Emissions)

Capabilities Exist. Tighter Regulations in EU, Japan, US are in place

Technology is available and in production

Cost to implement is reasonable

Experiments in various R&D Centres have been initiated

To Get Ahead of the Curve.

Growth Tighter Regulations required

Various refined fuels to be evaluated including Hydrogen

Lower Fuel Sulphur (to 50 PPM)

Retrofit Diesel (especially HD)


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Thanking You !

6. Emission Legislation & Aftertreatment Devices

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Transcript of 6. Emission Legislation & Aftertreatment Devices