Japan Clean Air Program 1 · 2020. 9. 30. · Japan Clean Air Program 11 STEP I Summary (1) 1. PM reduction-DPF exhibits remarkable PM reduction effects.The combination of high-performance

1Ｊａｐａｎ　Ｃｌｅａｎ　Ａｉｒ　Ｐｒｏｇｒａｍ

Future Challenges in Automobile and Fuel Technologies For a Better Environment

Diesel WG Report

September 25, 2000

JCAP Diesel WGToshiaki Kakegawa, Akihiro Misumi


ObjectivesObjectives１．To research diesel engine technologies and fuel technologies for automobile emission reduction and determine the mid-to-long term direction in these technology areas.　　　　　　　　　　　　 -Target: The assumption is the new long term regulation -Measurement item: Regulated components and 　　　　　　　　　 non-regulated components

２．Provide data required for improvement of Atmospheric model simulation accuracy

NOx, PM, etc.


　FY　　　　　　　　　　　　９７９７９７９７　　　　　　　　９８９８９８９８　　　　　　　　９９９９９９９９　　　　　　　　００００００００　　　　　　　　０１０１０１０１ STEP I STEP II

ScheduleSchedule

-Evaluation of existing technologies　-Existing-Model fuel

-Evaluation of future technologies-Future fuel

Evaluation of countermeasures for vehicles in use


　FY 97 98 99 00 01 STEP I STEP II

Contents of This ReportContents of This Report

1. Achievements in STEP I 2. Plan for Step II

3. Evaluation result of countermeasures for vehicles in use


What is PMWhat is PM

PM　（　（　（　（Particulate　　　　Matter）））） Minute Particles in diesel exhaust Visible Black smoke (soot, dry soot) Invisible Other combustion products (including sulfur-based sulfates contained in fuel) The components that can be dissolved in organic solvents are called Soluble Organic Fraction.

SOF

Sulfate

SOF: Soluble　Organic　Fraction

Soot


１．１．Achievements in STEP IAchievements in STEP I


Study Contents in STEP IStudy Contents in STEP I(１) Vehicle・ Engine

• 9 vehicles and 11 engines from passenger cars to heavy duty trucks were evaluated. ･Complied with 1989/short term/long term regulations.

　　･Besides high pressure injection and EGR, high-performance oxidation catalyst and DPF were also evaluated.

(２) Fuel • 13 types of fuels with different sulfur levels, distillation characteristics

and aromatic series contents were evaluated. ･ Sulfur 　　　　　　　　 0 - 500 ppm

･ Distillation characteristics Max. level in the market　　 (90 % distillation point) 　　　　　　 - ultra light quality

･ Aromatic series contents Max. level in the market – 0 %


Achievements in STEP I (1)Achievements in STEP I (1)Reduction effect of regulated components byhigh-performance oxidation catalyst

Results of 10/15 mode tests.Minus (-) in the table indicates increase.

ＰＭＮＯｘＨＣ COdiesel fuel S 0.04 % -25 -14 96 100

diesel fuel S 0.00 % 15 1 96 100

Emission reduction rate (Dummy catalyst base)

・For HC and CO, this latest catalyst technology can 　exhibit remarkable reduction effect.・The PM amount increases due to sulfate generation 　from sulfur contents


0

20

40

60

80

100

Benzene 1.3-Butadiene Formaldehyde Acetaldehyde Benzo[a]pyrene

Achievements in STEP I (2)High-performance oxidation catalyst effects for reducing5 non-regulated componentsRemarkable reduction of 5 non-regulated components is also made possible by thecatalyst.

w/ catalystUnder

detection limit

w/o catalyst

Underdetection limit

Underdetection limit


Achievements in STEP I (3)PM Reduction Effect by DPF

Large PM reduction. In particular,the dry soot reduction effect issignificant.

Cordierite honeycomb DPF w/o catalyst was used.

DPF (Diesel Particulate Filter)

0

0.2

0.4

0.6

0.8

1PM

em

issi

on (g

/kW

h)

Dry SootSulfatesSOF

DPF w/o w/ w/o w/

Fuel ＡＡＡＡＢＢＢＢ


STEP I Summary (1)

1. PM reduction

- DPF exhibits remarkable PM reduction effects. The combination of high-performance oxidation catalyst and low-sulfur diesel fuel is expected to significantly reduce dry soot, SOF, HC, CO, as well as non-regulated components.

-The effect on PM reduction resulting from diesel fuel characteristics(90% distillation temperature (T90), aromatic series content and sulfur level)was evident. However, the effectiveness varies considerably depending on vehicle and engine technologies.


STEP I Summary (2)

２．NOx reduction-The fuel effect on NOx is less than that for HC, CO, and PM. For reducing NOx, engine technologies will be the main solution.

３．Reduction of non-regulated components-The catalyst exhibits a considerable effect on the non- regulated components. Fuels have very little effect. However, more data should be collected to validate the measurement accuracy.


２．２．Plan for Plan for STEP IISTEP II


Study Contents in STEP II（１）Vehicle ・ Engine

• 10 vehicles (4 models) and 6 engines (3 models) ranging from passenger cars to heavy duty trucks are to be evaluated

• Target - the new long term regulation• Evaluate comprehensive systems consisting of DeNOx catalyst,

continuous regeneration DPF, high pressure injection and cooled EGR

（２）Fuel • 8 types of fuels with different sulfur levels and distillation

characteristics as well as 2 oxidized types to be evaluated.　　　• Sulfur 　　　　　　　　 10 - 500 ppm　 • Distillation characteristics Average level in the market - ultra light (90% distillation point) quality　　 • Oxidized basis 　　　　 2 types containing 10% blend (some vehicles)


Scenario for Emission ReductionEngine base, Japan 13 mode

PM

(g/kW

PM

(g/kW

PM

(g/kW

PM

(g/kW

PM

(g/kW

PM

(g/kW

PM

(g/kW

PM

(g/kW

････････ h)

h)

h)

h)h)

h)

h)

h)

NOx (g/kWNOx (g/kW･･h)h)

00

0.10.1

0.20.2

0.30.3

00 22 44 66 88

New short term New short term regreg

After treatment by oxidation catalyst, etc.

New long term reg

ContinuousregenerationDPF

High pressure injection

Long term exhaust levelLong term exhaust level

DeNOx catalyst

Cooled EGR

Cooled EGR


Absorption DeNox CatalystThree-way catalyst containing NOx absorber.Absorbs NOx and deoxidizes it periodically.Remarkab ly h igher NOx reduc t ion ra te thanconventional technologies.Sulfur poisoning(Sulfate storage) on NOx Absorber.

Absorb Deoxidize


Prototype Vehicle with AbsorptionDeNox Catalyst


Urea Selective Catalytic ReductionA system that creates ammonia, a reducing agent, byspraying urea in the exhaust pipe and purifying NOx inthe catalyst.Ammonia not reacted must be eliminated.Urea must be added periodically.

Hydrolysis of urea

(NH2)2CO + H2O 2NH3 + CO2

H S O

NOx Reduction by NH3

NO + NO2 + 2NH3 2N2 + 3H2O

Oxidation of slip NH3

4NH3 + 3O2 2N2 + 6H2O

Exha

ust

gas NOx

H2O, etc.

Purifiedgas

Urea/water solution injected　(Urea/Water　　　　Solution)

Concept Chart of SCR (Selective Catalytic Reduction)


Exhaust

Continuous Regeneration DPF (1)(Example: CRT TM by Johnson Matthey Co.)

Convert NO in the exhaust to NO2 at the catalyst located upstream.Collect soot in the filter downstream and oxidize it with NO2. PM regeneration is affected by NOx/PM ratio.

Pt　catalyst The soot regenerating filter

2NO + O2 2NO22NO + O2 2NO2 C + 2NO2 CO2 + 2NOC + O2 CO2

C + 2NO2 CO2 + 2NOC + O2 CO2


Continuous Regeneration DPF(2)

SO2 generated from sulfur in the fuel prevents the NO-to-NO2 reaction and causes plugging in the filter and backpressure increase.The soot regenerating filter can work at low temperature(from 260 Deg. Celsius).The low regeneration temperature provides to higherreliability.The fuel economy deterioration is low due to less backpressure increase. Not only PM but also CO, HC and fivenon-regulated components can be reduced by thecatalyst function.


　FY 97 98 99 00 01 STEP I STEP II

Progress

-Evaluation of future technologies-Future fuel

Evaluation result of countermeasures for vehicles in use

-Evaluation of existing technologies-Existing-Model fuel


3. 3. Evaluation Results of Countermeasures Evaluation Results of Countermeasures for Vehicles in Usefor Vehicles in Use


Purpose of Evaluation

To obtain technical data on the effects and issues anticipated from DPF installation to diesel vehicles in use.


Background of Evaluation of PM ReductionTechnologies for Vehicles in Use

(1) From the beginning of this year, public awareness of diesel PM has increased from the court ruling in the Amagasaki pollution case and the Tokyo Metropolitan　　Government ‘s proposal of mandatory DPF installation. (2) Nonetheless, many of the vehicles in use today that meet past regulations continue to emit high PM. This is an urgent problem that need to be solved. (3) To address the above problem, JCAP added the evaluation of PM reduction technologies for vehicles in use.


Engines Used for TestEngines Used for Test1999 long term reg.compliant engine

6925 cc175 kW667 Nm

w/ inter-cooler

turbocharger electronic control

1994 short term reg.compliant engine

9203 cc162 kW569 Nm

w/o turbocharger

1989 reg.compliant engine

11149 cc166 kW764 Nm

w/o turbocharger

Engine type

DisplacementPowerTorqueFeature


Fuel Used for TestFuel Used for Test

Existing diesel fuel

443 ppm57

325 °C0.832

Low sulfur diesel fuel

46 ppm59

334 °C0.831

Sulfur levelCetane number

90% distillation temperatureDensity


DPF Used for JCAP TestDPF Used for JCAP TestAlternate regeneration

Continuous regeneration

CRTCRTTM TM (CRT)(CRT)made byJohnson Matthey Co.

DPXDPXTMTM(CSF(CSF))made byEngelhardCo.

(Heat and burn by heater)

Alternate regeneration DPF made by Isuzu

Pressure sensor (upstream)

Changeover valveEngine

Filter Pressure sensor (downstream)

PM burning heaterControl unitHigh power ACG

Ceramic filterTraps almost all particles

containing SPM and regenerates them with NO2.

Pt oxidization catalystOxidizes HC and CO, and generates NO2.


Evaluation of DPFEvaluation of DPF

①

②

③

The following three points are key for DPF evaluation.

Engine

How long is it able to maintain the above performances

To what degree is it able to reduce PM dispersing in the air? Reduction effect

　　　　　　　　　　 How efficiently is it able to remove PM?

Atmosphere

Regeneration performance

Fleet test


First PointFirst PointPM Reduction EffectPM Reduction Effect


Comparison of PM Reduction EffectComparison of PM Reduction Effect

00.10.20.30.40.50.60.70.80.9

1989 reg. Short-term reg. Long-term reg.

PM e

mis

sion

(g/k

Wh)

Base (S500 ppm)Base(S 50 ppm)CRT (S500 ppm)CSF (S500 ppm)CRT (S 50 ppm)CSF (S 50 ppm)

Alternate Regeneration

DPF

(a) When 50 ppm diesel fuel was used, CRT and CSF showed remarkable reduction effect exceeding 95% in 1989 and short-term regulation/ compliant engines.(b) When the only 500 ppm diesel fuel data was compared, the alternate regeneration type had the highest reduction effect. Also, the long-term regulations compliant vehicles without DPF showed lower PM emission than the 1989 and short-term standard compliant vehicles with DPF.(c) The long-term standard compliant engine used in this test showed increase in PM both by CRT & CSF when 500 ppm diesel fuel was used.

Alternateregeneration typeused only S 500ppm diesel fuelfor the test.


Summary of PM Reduction EffectSummary of PM Reduction Effect

50

Alternate regeneration

元年

９９

９８

６４

７０

８４

８４

短期

９９

９７

４２

６１

－

－

長期

８４

９３

Δ１６０

Δ１３２

－

ー

98 %

97 %

-

97 %

Urban drive(JARI transient test cycle)

Steady drive (D13 mode)

A; Cordierite honeycomb + heater (tested in JCAP STEP I)B; SiC fiber + heater

CRTCSFCRTCSF

DPFTest engine Test engine

A

B

Sulfur in fuel（ｐｐｍ）

80 %

Increase

Long-term reg.

84 %93 %

More than95 %

40 – 70 %

1989 & short-term reg.

500

500

short-term reg.


Reduction Effect Other Than PMReduction Effect Other Than PM

HC

0

0.5

1

1.5

2

40 55 70 85 100

Engine load (%)

THC

(g/k

Wh)

The reduction effect for HC and CO is also remarkable.

1989 regulations compliant engineFuel 2D-04 (50 ppm)

CRT inletCRT outlet

RPM point equivalent to 80% of max. power

0

2

4

6

40 55 70 85 100

Engine load(%)

CO

(g/k

Wh)

CO


Summary of PM Reduction EffectSummary of PM Reduction Effect1.Alternate regeneration DPF -Exhibits high level of PM reduction effect.

2.Continuous regeneration DPF (1) In case of fuel with 50 ppm sulfur -Exhibits extremely high level of PM reduction effect. (2) In case of fuel with 500 ppm sulfur -Exhibits only poor PM reduction effect. Conversely, PM emission increases in the long-term regulations compliant engines. (3) Also has high reduction effect on HC and CO.


Second PointSecond PointRegeneration PerformanceRegeneration Performance

Study with Continuous Regeneration Type


Factors Affecting CRT RegenerationFactors Affecting CRT Regeneration

１．１．１．１．Temperature

The regeneration of CRT by NO2Combustion can occur at lower temperature than oxygen but requires at least 260 °C.

２．２．２．２．NOx/PM ratio

2NO + O2 2NO2

In quantitative terms;　　　　　　　　NOx/PM ratio > 8

Recommendation: NOx/PM ratio > 24

NO2 generation

C + 2NO2 CO2 + 2NO

Oxidation of NO2

←→


0

100

200

300

400

500

600

700

Engine RPM (%)

0

100

200

300

400

500

600

700

Engine RPM (%)

0

100

200

300

400

500

600

700

40 60 80 100

Engine RPM (%)

CRT Regeneration Temperature RangeCRT Regeneration Temperature Range(Sulfur level 50 ppm)

Year 1989regulation

Short-termregulation

Long-termregulation

●: Regenerated (Differential pressure before and after DPF decreased or made no change.)X: Not regenerated (Differential pressure before and after DPF increased.)

CR

T in

let t

empe

ratu

re ( °

C)

10040 60 80 40 60 80 100


Able to regenerate

Difficult to regenerate

The NOx/PM ratio level defined in the Japanese diesel emissionregulations up to the present is too low to cause CRT regeneration.

CRT Regeneration Conditions and NOx/PM ratio

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0NOx g/kWh

PM g

/kW

h

USEUJPN

2000 （EuroⅢ)

2005（EuroⅣ)2008（EuroⅤ）

2004

1998Truck

1998Bus2007 ULEV(Nox+HC) 2000New long term regulations

1999

2004

200?

1996

Year 1989 regulations (No PM limit;only smoke

regulations)

Year 1994 regulations (short-term)

Long term regulationsNew short term regulations

★

★★

★

★: Engine tested

NOx/PM=20

NOx/PM=10

NOx/PM=50

Diesel Regulations Criteria Comparison Between US/EU/JPN


0

100

200

300

400

500

600

700

Engine RPM (%)

0

100

200

300

400

500

600

700

Engine RPM (%)

0

100

200

300

400

500

600

700

Engine RPM (%)

CSF Regeneration Temperature RangeCSF Regeneration Temperature Range(Sulfur level 50 ppm)

Year 1989regulations

Short-termregulations

Long-termregulations

40 60 80 100 40 60 80 100 40 60 80 100CSF

inle

t tem

pera

ture

( °C

)

●: Regenerated (Differential pressure before andafter DPF decreased or made no change.) X: Not regenerated (Differential pressure beforeand after DPF increased.)


Actual Status of Exhaust TemperatureActual Status of Exhaust TemperatureStudied through JARI engine test cycle

Transient mode simulating a urban drive in Tokyo area

Average vehicle speed: 26 km/h, 1 cycle: approx. 31 minutes

（km/h)

（%

）

(sec.）

City Highway City CityHighway

（%

）


Exhaust Temperature MeasurementsExhaust Temperature Measurements

0100200300400500

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Time s

Fuel:2D-04(S:50)

DPF inlet Average 160 °C 　（290 °C max.）（Engine outlet 390 °C max.）

Average 160 °C 　

390 °C290 °C

JARI engine test cycleShort-term regulations compliant engine

DPF inlet

Engine outlet

Exha

ust t

empe

ratu

re ( °

C)

(sec.)


In typical urban driving, the exhaust temperature does not reach the regeneration threshold.

Does the exhaust temperature Does the exhaust temperature reaches a level that causes CSF to reaches a level that causes CSF to regenerate during urban driving conditions ? regenerate during urban driving conditions ?

CSF

inle

t gas

tem

pera

ture

(°C

)

0

100

200

300

400

500

600

700

0 20 40 60 80 100 120Engine RPM (%)

JARI engine test cycleShort-term reg. compliant engine

●: Regenerated(Differential pressure before and afterCSF decreased or made no change.)

X: Not regenerated(Differential pressure before and afterCSF increased.)

CSF inlet temperature during JARI engine test cycle drive


When the exhaust temperature does notWhen the exhaust temperature does not reach the regeneration threshold, does reach the regeneration threshold, does PM accumulate in CSF? PM accumulate in CSF?

0

0.5

1

1.5

0 5 10 15 20 25# of test cycles

Diff

eren

tial 　

pres

sure

incr

ease　

[kPa

] Fuel　S=500 ppmFuel　S= 50 ppm

Result of engine test equivalent to 300 km drive The differential pressure before and after CSF continuously increases　　(indicates PM accumulation)

JARI engine test cycleShort-term regulations compliant engine + CSF


Summary of CRT Regeneration PerformanceSummary of CRT Regeneration Performance

(1) On 1989 and short-term reg. engines, regeneration is observed in some mid-to- high speed RPM ranges.(2) On long-term reg. engines, regeneration zone is wider than 1989 and short-term reg. engines.(3) On short-term reg. engines, no regeneration is observed in repeated JARI engine test cycles.


Summary of Regeneration PerformanceSummary of Regeneration Performance

-No regeneration observed in repeated JARI engine test cycles

Short-termreg. engine

-Regeneration zone expanded further than short-term reg. engine

-Regeneration zone wider than 1989 reg. and short- term reg.

Long-termreg. engine

-Regeneration zone in high RPM expanded on engines complying with 1989 reg. or above.

Short-termreg. engine

-Regeneration observed in all ranges at exhaust temperature of 400°°°°C or higher

-Regeneration observed in some mid-to-high speed RPM ranges

Year 1989 reg.engine

CSFCRTEngineR

egen

erat

ion

obse

rved

Urban drive mode


Summary of CSF Regeneration PerformanceSummary of CSF Regeneration Performance

(1) In 1989 reg. engines, regeneration is observed in all ranges at exhaust temperature of 400°°°°C or higher.(2) In short-term reg. engines, regeneration zone stretches further at high RPM than 1989 reg. engines.(3) In long-term reg. engines, regeneration zone is expanded further than short-term reg. engines.(4) In short-term reg. engines, no regeneration is observed in repeated JARI engine test cycles.


General SummaryGeneral Summary1. Fuel requirements

- Low sulfur diesel fuel is needed to enhance CRT/CSF performance.2. Applicability to vehicles in use - There are a few opportunities for application under typical driving conditions in Tokyo urban areas. - Some opportunities can be found in vehicles that run under conditions where exhaust temperature is likely to increase. - CRT is considered difficult to apply to vehicles released before 　 the short-term regulations were introduced because they have small NOx/PM ratios.３．Generalization - The technologies studied here can apply to vehicles in use if combined with new engine technologies, though opportunities　　 are limited.


ENDEND

Documents

Japan Clean Air Program 1 · 2020. 9. 30. · Japan Clean Air Program 11 STEP I Summary (1) 1. PM reduction-DPF exhibits remarkable PM reduction effects.The combination of high-performance