TOYOTA

Development on simultaneous reduction system of

NOx and PM from a diesel engine

TetsuTetsu WatanabeWatanabeTOYOTA MOTOR CORPORATIONTOYOTA MOTOR CORPORATION

１

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Contents

1. Concepts of Simultaneous PM and NOx Reduction System

2. Emission Data of DPNR field trial in Europe

４. Application of DPNR for Light-Duty Truck

3. Emission Potential in USA FTP 75 testing Mode

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1. Concepts of Simultaneous PM and NOx Reduction System

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Enlarged view of exhaust gas flowing substrate wall

Exhaust gas

NOx, storage reduction catalyst

NOx storage reduction catalyst

Fine porous ceramic structure

Exhaust gas flow

Fine porous ceramic structure

Exhaust gas

DPNR Catalyst

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NOxNOx

LeanLean RichRich

PMPM

Reduction of NOxReduction of NOx

HCHCCOCO

HH22OONN22

NONO＋＋O*O*PtPtCOCO22

Filter SubstrateFilter Substrate

O*O* O*O*

COCO22

PtPt

PMPM

Filter SubstrateFilter Substrate

Storage of NOxStorage of NOx

NONOOO22 NONO22++O*O*

SubstrateSubstratePtPt

NO+ONO+O22 COCO22

PtPtO*O*

PMPM

NONO22

SubstrateSubstrate

NOx NOx Storage Storage MaterialMaterial

Continuous OxidationContinuous OxidationContinuous OxidationContinuous Oxidation

NOx NOx Storage Storage MaterialMaterial

NOx and PM Reaction Mechanism NOx and PM Reaction Mechanism of DPNR Catalystof DPNR Catalyst

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Stored NOx

NOx Reduction

Exhaust Port InjectionN

Ox

(mg/

s)A

ir Fu

el R

atio

101520253035

0

5

10

15

100secTime

Cat. In

Cat. Out

2L TDI2900 rpmPme=0.50MPaInjection Interval = 10sec

Characteristics of NOx Storage Reduction

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Effect of air-fuel ratio modulation on ESR spectra in DPNR catalyst

7S.Hirota etc. JSAE Paper 20034054(Japanese)

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Effect of the amount of active oxygen on PM oxidation rate

8S.Hirota etc. JSAE Paper 20034054(Japanese)

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Vehicle Speed 60km/h Const.

100sec.

Bed

Tem

p.(d

eg.C

)

Time300400500600700

Cat. FrontCat. Rear

Air

Fuel

Rat

io

10152025

3530

Low temp.combustion & EPI

SO

x, H

2S(p

pm)

200400600

0H2S

SO2800

Rich and lean

Characteristic of SOx DischargingPassenger VehicleEngine : 2L TDI, DPNR ： 2L

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Characteristic of Forced PM Oxidation

Tem

p.(d

eg.C

)

200300400500600700

Bed Temp.

Cat. Inlet Temp.

Sto

red

PM

Qua

ntity

(g)

Time100sec.0246

Veh

icle

Spe

ed(k

m/h

)4080

0Forced PM Oxidation

Air

Fuel

Rat

io

1520

3025

with Exhaust Pipe Injection

Passenger Vehicle, Engine : 2L TDI, DPNR ： 2L

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10 6

10 7

10 8

10 9

1010

1011

1012

1 10 100 1000PM Diameter(nm)

before DPNR

60km/h constant speed

PM (N

umbe

r/km

)Distribution of PM diameter

after DPNR

Measured by SMPS

11

on forced oxidationafter DPNR

2L TDI

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2. Emission Data from DPNR field trialin Europe

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Conditions Country Driving pattern Nr. Of cars Fuel S content

HighwayCity

Normal Germany

Standard

27 39ppm

CityNormal UK

Standard19 35 ppm

High altitude Austria Standard 7 277 ppm

Cold area Norway City - Standard 3 30 ppmHighwayNormal Italy

City2 271 ppm

Cold area Finland Standard 1 32 ppmNormal Belgium Standard 1 50 ppm

Field trial overview

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c Engine Specification

14

82.2mm*94mm

Field Monitoring Car

Power 81(kW) at 4000 rpm

Max.Torque250(Nm) at2000-2400rpm

Combustion Noise at 750 rpm Idle 68.0 (dB)

Compression ratio 18.2:1

Injection system2nd Generation CR

(Max.180MPa)

Current Model

(Max.135MPa)

18.6:1

←

73.0 (dB)

250(Nm) at2000-2400rpm

1st Generation CR

Swept Volume 1995cc ←

Bore*Stroke ←

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Oxidation Catalytic Converter

DPNR Catalytic Converter

Base Vehicle :AvensisIW 1470kg

Base Engine:1CD-FTVｚ

c Installation of DPNR

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cc Emission History

STEP 4

S 50ppm

0

0.05

0.10

0.15

0.20

0.25

0.30

0 20000 40000 60000 80000 100000

Running distance (Km)

NO

x (g

/Km

)

In House Data

Standard, High Speed Pattern

S 300ppm

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cc Emission History

17

0

0.005

0.010

0.015

0.020

0.025

0.030

PM (

g/K

m)

In House Data

STEP 4

0 20000 40000 60000 80000 100000

S 300ppm

Standard, High Speed Pattern

Running distance (Km)

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0

0.5

1.0

1.5

2.0

0 50000 100000 150000 200000Rel

ativ

e Pr

essu

re D

iffer

ence

Target

All Driving Pattern

cc Pressure Drop History

Running distance (Km)18

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3. Emission Potential for US Regulation

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Emission on US FTP75 modeEmission on US FTP75 mode

Test Cycle

PM(g/mile)

NOx(g/mile)

NMHC(g/mile)

CO(g/mile)

CO2(g/mile)

FE(mile/gal)

FTP75

US06

SC03

HWFET

NYCC

From SAE2002-01-2877 J.McDonald,B.Bunker

Fresh Cat.& Fuel:C.N.50.4 Aromatics26.0% Sulfur 6ppm

0.0057

0.005

0.007

0.002

0.007

0.05

0.14

0

0

0

0.07

0.19

0.14

0.12

0.04

0

0

0

0

0

273

289

367

192

474

37.2

35.2

27.7

52.9

21.5

20

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0

5

1015

20

25

35 38 40 43 46 48 51 53 56 59Cetane Number

Freq

uenc

y （

％）

0

5

1015

20

25

5 10 15 20 25 31 36 41 46 52Total Aromatics （vol. ％）

Freq

uenc

y （

％）

557 samples of US fuel（ '00 Winter - '02 Summer, surveyed by AAM）

Cetane NumberAve. 44.8Max. 60.1Min. 37.8

Total Aromatics (%)Ave. 35.8Max. 54.2Min. 9.8

Extreme low cetane and high Aromatics diesel fuelshave existed in the US market.

West EuropeJapan

West EuropeJapan

U.S.A.

U.S.A.

Cetane Number and Aromatics in US Market

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４. Application of DPNR for Light-Duty Truck

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DPNR catalystDPNR catalystand oxidation catalystand oxidation catalyst

Installation of DPNRInstallation of DPNRfor Lightfor Light--Duty Truck Duty Truck

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TOYOTAPressure Sensor Pressure Sensor Fuel InjectorFuel Injector

EGR Valve EGR Valve

EGR Cooler EGR Cooler

Throttle Valve Throttle Valve

Common Rail Injection System Common Rail Injection System

VG Turbo Charger VG Turbo Charger

Air flow Sensor Air flow Sensor

Temp.Sensor Temp.Sensor

Inter-Cooler Inter-Cooler

Intake AirIntake Air

DPNR Catalyst DPNR Catalyst

Air-Fuel Ratio Sensor Air-Fuel Ratio Sensor

Engine Control Unit Engine Control Unit

Oxidation Catalyst Oxidation Catalyst

Exhaust GasExhaust Gas

System Diagram of DPNR

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Decrease of NOx Storage Capacity according to continuous engine operation

Rel

ativ

e no

rm.N

Ox

Rel

ativ

e no

rm.N

Ox

stor

age

capa

city

stor

age

capa

city

0000 500500 10001000 15001500 20002000

2.02.01.51.51.01.00.50.5

3.03.02.52.5

Time (hour)Time (hour)

Sulfur 7ppmSulfur 7ppm

Sulfur 40ppm

= 200,000= 200,000kmkm

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PM Reduction Ratio TransitionPM Reduction Ratio Transitionthroughout the Durability Testthroughout the Durability Test

PM re

duct

ion

PM re

duct

ion

ratio

(%

)ra

tio (

%)

707000 500500 10001000 15001500 20002000

9090858580807575

1001009595

Time (hour)Time (hour)

Japan D 13 modeSulfur 40ppm

= 200,000= 200,000kmkm

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PM (

g/kW

h)PM

(g/

kWh)

NOx (g/kWh)NOx (g/kWh)

0.10.1

0.20.2

0.30.3

1.01.0 2.02.0 3.03.0 4.04.0 5.05.00000

Japan newJapan newshort term short term

Japan D13 modeJapan D13 mode

Before cat.Before cat.Fresh cat.Sulfur:7ppm(estimated).

Japan new long termJapan new long term

Aged cat.Aged cat.(2000hrs.)(2000hrs.)sulfur:40ppmsulfur:40ppm

Emission Potential of Aged Cat.

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Summary

■ The effects of aged DPNR has been verified byvehicle field testing in Europe and long hoursdurability testing on engine bench for Japanese market.

■ On USA FTP75 testing, DPNR with fresh catalystshown remarkable emission reduction efficiencyalthough durability of catalyst is severe subject.

■ Fuel specificatins, such as S contents, cetane number and aromatics, are very important for the realization of very low emission diesel engine.

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The end of presentationThank you for your attention

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Emission Regulation Trend Emission Regulation Trend HDT CategoryHDT Category

0.40.40.30.30.20.20.10.1

00

PM (

g/kW

h)PM

(g/

kWh)

8866442200

ＮＯｘ

ＮＯｘ(( g

/kW

h)g/

kWh)

Euro 5Euro 5

'00'00 '02'02 '04'04 '06'06 '08'08 '10'10

Euro 4Euro 4

YearYear

New long termlong termNew short term

Euro 3Euro 3

Japan long term

a

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System Control Strategies- Forced PM Oxidation-

Engine speedEngine speed(% of rated speed)(% of rated speed)

Torq

ue (%

)To

rque

(%)

100100

8080

6060

4040

001001008080606040402020

2020

Normal combustion Normal combustion + post injection

Normal combustion + 2 times post injections

Main inj.

BDCTDC

Post inj.

Main inj.1st. Post inj.

BDCTDC

2nd. Post inj.

b

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System Control Strategies- Sulfur Discharging-

Engine speedEngine speed(% of rated speed)(% of rated speed)

Torq

ue (%

)To

rque

(%)

100100

8080

6060

4040

001001008080606040402020

2020

Normal combustion + post injection

Low temp. combustion + exhaust pipe injection

Main inj.

BDCTDC

Post inj.

Main inj.

TDC

Fuel injection from exhaust pipe injector

+

operating zone ofsulfur discharging

c

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■■ Reduction of Cost

■■ Improvement of Durability・・Heavy Duty Truck : Guarantee over 650,000 km

(in Japanese Case)

・・Further simple control system

■■ Improvement of Fuel Economy・・Rich pulse for NOx and PM reduction・・Regeneration of sulfur poisoning

Technical Issues of DPNRTechnical Issues of DPNR

d

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33

11

44

00100100

22

200200 300300 400400 500500Bed TemperatureBed Temperature

in DPNR Catalyst (in DPNR Catalyst (ººC)C)

PM O

xida

tion

and

Engi

ne

PM O

xida

tion

and

Engi

ne

out

PM R

ate(

Rel

ativ

e)ou

t PM

Rat

e(R

elat

ive)

Engine out PMEngine out PMEngine : TDI, 2LEngine : TDI, 2LDPNR DPNR ：： 3L3L

Relationship between PM Oxidation Rate Relationship between PM Oxidation Rate and Bed Temperature in DPNR Catalystand Bed Temperature in DPNR Catalyst

e