PN emissions from Japanese engines with catalyzed DPF system- Effect of Cycle Exhaust Temperature

Prepared for

2009/3/30 PMP-WG MEETING

JASIC

The Japanese Heavy-Duty inter-laboratory exercise has been conducted at the Japan Automobile Research Institute (JARI) and the National Traffic Safety and Environment Research Laboratory (NTSEL). The works were undertaken on a Hino J08E Heavy-Duty engine equipped with a Catalyzed Diesel Particulate Filter (C-DPF),

The evaluation of another Japanese engine is also conducted at JARI. The engine basically adopts same emission control technologies but showed different PN emission characteristics.

An analysis was conducted and the result showed that the exhaust temperature of the engine was higher than J08E, and by this self-regeneration of DPF occurred during the test cycles and which led to high PN emissions.

Outline

Engine A (JAPAN) B (J08E)Cursor 8 for PMP

Validation

Displacement 5193 cc 7684 cc 7.8 L

Max. Power / Rev.

154 kW

/ 2600 rpm

177 kW

/ 2700 rpm

260 kW

/ 1900~2400 rpm

Max. Torque / Rev.

637 Nm

/ 1600 rpm

716 Nm

/ 1600 rpm

1280 Nm

/1000~1900 rpm

DPF typeC-DPF

(Cordierite)

C-DPF

(Cordierite)CRT

(Cordierite)

Engine Specifications

Both Engine A and B are the newest 2005 model with cooled EGR & DPF, and B is used for Japanese round-robin test.

Engine A adopts higher boosting design which resulting higher exhaust temperature than B.

Test ScheduleEngine A Engine B Cursor 8

TB measurement TB measurement IFV

WHTC-ColdWHTC-Cold WHTC-ColdWHTC-Cold WHTC-ColdWHTC-Cold

10 min soak 20 min soak 10 min soak

WHTC-HotWHTC-Hot WHTC-HotWHTC-Hot WHTC-HotWHTC-Hot

10 min Mode9 (WHSC)6 min Idle + 5min soak

10 min Mode9 (WHSC)

2 min Idle + 5min soak

10 min Mode9 (WHSC)

WHSCWHSC WHSCWHSC WHSCWHSC

20 min Full-Full 20 min Full-Full 5 min Mode7(ESC)

3 min idle

10 min soak 10 min soak ETCETC

JE05 Precon JE05 Precon 5 min Mode7(ESC)

3 min idle

10 min soak 10 min soak ESCESC

JE05JE05 JE05JE05 Power Curve

DPF regeneration

20 min Full-Full

WHTC-hot

15 min Mode10(ESC)

30 min Mode7(ESC)

Pre-conditionning

1.00E+09

1.00E+10

1.00E+11

1.00E+12

PN

em

issio

n (

#/k

Wh

)

WHTC-Cold 5.41E+11 1.59E+11 3.50E+11

WHTC-Hot 2.98E+11 8.50E+09 5.00E+09

WHSC 4.25E+11 5.98E+09 4.00E+10

JE05 1.11E+11 3.68E+11

Engine A Engine B Cursor 8

PN emission （ WHTC WHSC JE05)

Engine A showed lower PN emission in JE05

Engine A showed higher PN emission level than others, in WHTC and WHSC.

0.0E+00

3.0E+09

6.0E+09

9.0E+09

1.2E+10

1.5E+10

0 200 400 600 800 1000 1200 1400 1600 1800Time (sec)

0

100

200

300

400

500

Te

mp

. (d

eg

. C)

PN emission DPF inlet temp. DPF outlet temp.

0.0E+00

3.0E+07

6.0E+07

9.0E+07

1.2E+08

1.5E+08

0 200 400 600 800 1000 1200 1400 1600 1800Time (sec)

0

100

200

300

400

500

Tem

p. (

deg.

C)

PN emission DPF inlet temp. DPF outlet temp.

Time History of PN emission and exhaust temperature during WHTC-Hot cycle

Remarkable increase in PN emission occur when the DPF inlet temperature exceeds 400 deg. C in Engine A.

PN

em

issi

on (

#/kW

h/se

c)P

N e

mis

sion

(#/

kWh/

sec)

Engine A

Engine B

Time History of PN emission and exhaust temperature during WHSC cycle

0.0E+00

5.0E+11

1.0E+12

1.5E+12

2.0E+12

2.5E+12

0 200 400 600 800 1000 1200 1400 1600 1800Time (sec)

0

100

200

300

400

500

Te

mp

. (d

eg

. C)

PN emission DPF inlet temp. DPF outlet temp.

0.0E+00

1.0E+07

2.0E+07

3.0E+07

4.0E+07

5.0E+07

0 200 400 600 800 1000 1200 1400 1600 1800Time (sec)

0

100

200

300

400

500

Tem

p. (

deg.

C)

PN emission DPF inlet temp. DPF outlet temp.

Engine A

Engine B

PN

em

issi

on (

#/kW

h/se

c)P

N e

mis

sion

(#/

kWh/

sec)

Remarkable increase in PN emission occur when the DPF inlet temperature exceeds 420 to 450 deg. C in Engine A.

0

0.2

0.4

0.6

0.8

1

50 100 150 200 250 300 350 400 450 500

Exhaust gas temperature in sampling point of partial tunnel (°C)

Cu

mu

lativ

e f

req

ue

ncy

WHTC

ETC

FTP

WHSC

ESC

J13

ESCJ13

ETCFTP

WHTC

WHSC

An Example of Exhaust Temperature Distributions During Emission Test Cycles ( Japan 2003 model engine case)

High Low

ESC .> J13 > WHSC > ETC > FTP > WHTC

European Validation Test Result(JRC report; 　 Iveco Cursor 8)

SummaryIn our test there occurred regeneration phenomena of DPF during the test cycle operation of WHTC/WHSC, with engine A. Because of this, PN emission of engine A for both WHTC and WHSC is extremely higher than other engines. The mechanism of the phenomena is considered that the exhaust temperature exceed the self-ignition temperature (over 400 deg. C) of accumulated soot on C-DPF. This seems a special case for WHTC cycle to reach such a high temperature, but it is feasible for WHSC cycle, in which the maximum exhaust temperature is 50~100 deg. C higher than WHTC.In the case of CRT the precious metal catalyst is not coated on DPF itself, so the self-ignition temperature for the accumulated soot will be higher than C-DPF, and regeneration during the test cycle will be less probable. But it will be noted that the PN emission of the European validation test engine with ESC cycle showed the highest value.