Recent Topics in Diesel Engine Emission Measurement

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Recent Topics in Diesel Engine Emission Measurement

著者（英） Masayuki Adachi journal or

publication title

国際セミナー「エンジンの低エミッション化と燃焼制御」

page range 1‑12

year 2006‑07‑12

権利（英） Research Center for Energy Conversion System of Doshisha University

URL http://doi.org/10.14988/re.2017.0000015724

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International Seminar on Low Emission Aspect and Combustion Control for Engine Systems Doshisha University, Energy Conversion Research Center

July 12, 2006 Masayuki Adachi, Dr. Eng.

General Manager, HORIBA Automotive Test Systems

Recent Topics in Recent Topics in

Diesel Engine Emission Measurement Diesel Engine Emission Measurement

Contents Contents

1. PM Measurement dilemma

2. Enhanced gravimetric techniques 3. PM counting method

4. Conclusion

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PM Measurement Dilemma 1 PM Measurement Dilemma 1

Conventional method is facing a limit of precision

Current measurement methods are based on “old dirty”diesel engines Advanced diesel engine systems generate significantly low emission

Nuclei-mode particle controversy

Need to measure due to health hazard Mostly heavy hydrocarbon particles?

Sulfur mist as core??

Extremely high variability depending on sample condition – Dilution ratio, temperature, residence time, etc…

PM Measurement Dilemma 2 PM Measurement Dilemma 2

Scientific vs. Industrial

Thorough scientific characterization of particle emission needs highly skilled PhDs

Regulatory procedure (industry protocol) must be reproducible for everyone in the industry

PM definition in gravimetric method

Exhaust gas is diluted and controlled at lower than 52 degC Filter (0.3u, >99%) is used for collection

After PM collection, filter is soaked for 8(LDD) / 1-80(HDD) hours, 23 degC w/ defined humidity

Weigh everything on the filter as PM

Gas absorption. PM mass being much less than 1/1000 of filter.

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The “ The “well known well known” ” diesel PM size distribution diesel PM size distribution

Source: David Kittelson

0 0.05 0.1 0.15 0.2 0.25

0.001 0.010 0.100 1.000 10.000

Diameter ( ^m)

ConcentrationN/Nmax(%)

Mass Number Surface Area Fine Particles Dp < 2.5 m Ultrafine Particles

Dp < 100 nm Accumulation Nuclei Mode Mode

Coarse Mode

Small

Small LargeLarge

LowLow HighHigh

Unstable NMHCs

Stable

Coagulation particles

Enhanced Gravimetric Techniques

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EPA 2007 HDD Regulation 1 EPA 2007 HDD Regulation 1

First proposal in the world to enhance precision of the HDD measurement

Revised standards:

NOx: 0.20g, NMHC: 0.14g, CO:15.5g, PM:0.01g /bhp-hr Use of sub-sonic venturi for CVS

Dilution air: >15degC, HEPA filtered

Filter temperature: within 5 degC from 47degC, TX40 or Teflo Use cyclone to cut 50% of 2.5-10u and bring 99% of 1.0u

Recent USEPA/CRC study at SwRI E-66

Study evaluated filter media Residence time effects

DPF equipped 2007 compliant engines with controlled DPF bypass Partial flow systems

Study complete and final report due soon

EPA 2007 HDD Regulation 2 EPA 2007 HDD Regulation 2

CVS

PDP/CFV

ＦＦ

Ｐ B

TB ^EXH.

EXH.

Primary Dilution Tunnel

Secondary Dilution Tunnel Secondary

Dilution Air Control Unit E/G

Dilution Air

Sample Bypass

Conventional

Ｔ＝２５±５℃

T=25±5degC Sampling Unit

Sampling Unit

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EPA 2007 HDD Regulation 3 EPA 2007 HDD Regulation 3

CVS

PDP/CFV/SSV

ＴＳ

ＦＦＦ

ＴＳ

ＰＢ

TB ^EXH

EXH Primary Dilution Tunnel

Secondary Dilution Tunnel Secondary

Dilution Air Control Unit Sampling Unit

Sampling Unit Heated BOX Ｅ／Ｇ

Dilution Air

Ｔ＝４７±５℃

Φ４７（Effective area >Φ３８）

Single Filter Face Vel. < １００ｃｍ/ｓｅｃ

Pre-classifier T>15degC

An Interpretation

Sample (HOT START)

Ｓａｍｐｌｅ

（ＣＯＬＤＳＴＡＲＴ）

Bypass Ｆ

T>15degC

HEPA Filter Minimum Heat Capacity

PM Transfer Tube

・Diameter >0.85cm

・Length < 91cm

Filter holder must be within 30.5cm from 2^ndtunnel

Flow rate < 68L/min Heated Line

Discussions for filter material 1 Discussions for filter material 1

Gaseous HC conversion to PM mass

Mass collected can be overwhelmed by absorption of gaseous hydrocarbons

Vogt, Chase, Maricq, Ford Motor company, http://ies.jrc.cec.eu.int/Units/eh/events/EURO5/

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Soot removal by DPFs Soot removal by DPFs

0 0.05 0.10 0.15 0.20 0.25

Without CRT

SULFATE (mg) VOF (mg) SOOT (mg)

With CRT

Hydrocarbon is becoming as a major constituents of PM Hydrocarbon is becoming as a major constituents of PM Is this gaseous HC, non

Is this gaseous HC, non- -gaseous HC, or both? gaseous HC, or both?

Measured by thermal mass method Measured by thermal mass method

Discussions for filter material 2 Discussions for filter material 2

Vogt, Chase, Maricq, Ford Motor company, http://ies.jrc.cec.eu.int/Units/eh/events/EURO5/

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A proposal for new style filter A proposal for new style filter

A new concept filter material

Teflon membrane w/ unwoven PET backing

Developed primarily for ambient PM component speciation Evaluations to be made for automotive applications

PET backing Teflon membrane

Shinohara, et.al., European Aerosol Conference 2004 and 2005

Particle Counting Technique

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GRPE

GRPE - - Particulate Measurement Program Particulate Measurement Program

The PMP program is organized under the UNECE WP29/GRPE Group

Aim is to develop a new system of PM measurement (instrument, sampling and procedures) to complement or replace the existing gravimetric method

PMP is open to governments or industry who are members of GRPE.

Each contributor funds their own research

All results are shared and will be published during and at the end of the two year program

PMP positioning PMP positioning

(WP29)

World Forum for Harmonization of Vehicle Regulation United Nation

(ECE)

Economic Commission for Europe

General Safety

GRSG Collision Safety

GRSP Brake and Accelerator GRRF

Emission and Energy

(GRPE) Noise and Vibration GRB

Light and Signal GRE

WHDC WMTC

PMP ^WWH-OBD

Particulate Measurement Program

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GRPE- GRPE -PMP activity PMP activity

Besides the conventional gravimetric filter technique, many alternative methods have been developed

Development has been accelerated by the GRPE-PMP activity

CPC/CNC - Condensation Particle Counter DCS - Diffusion Charging Sensor

EDB - Electrical Diffusion Battery PASS - Photo Acoustic Soot Sensor ELPI - Electrical Low Pressure Impactor LII - Laser Induced Incandescence PAS - Photoelectric Aerosol Sensor

TEOM - Tapered Element Oscillating Microbalance QCM - Quartz Crystal Microbalance

DMS - Differential Mobility Spectrometry

MEXA -MEXA 1370PM : PM mass by gas analysis EPA-2007 “style”GRAVIMETRIC as a reference method

GRPE Informal Document: GRPE-48-11-Rev.1

PMP PMP Recommendation for counting Recommendation for counting

Particle Number Diluter 1 Dilute with 150degC air to avoid HC condensation Evaporation Tube

300〜400℃

Particle Number Diluter 2

Dilute with ambient temperature to avoid condensation and thermophoretic loss

CPC cuts 23nm or lower

Cut 2.5 or larger particles by cyclone CVS Dilution tunnel

HEPA and Charcoal filter

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A prototype flow schematics A prototype flow schematics

VP TC4

PT4 PT3

VP

47℃

PT2

PT１ TC6

CFO1

CFO2 BV1 BV2 BV8

CFO３

PND1 PND2

DR：10〜1000

@150℃ DR：10〜50

@Room Temp 99% Removal

@320℃

MFC

VPRVPR PNCPNC

PCFPCF

CFO4 CFO5 CFO6

Constant Flow

CPC

TC1

Wei, et.al., SAE2006-01-0865

SPCS particle penetration SPCS particle penetration

1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07

1 10 100 1000

Log Dp

Concentration dN/dLogDp

Raw DR 500 DR 750 DR 1000

Small Particle size nm Large

Diluted concentration Raw concentration

No size change

Penetration >98%

0 20 40 60 80 100

200 300 500 750 1000

Dilution ratio

Penetration %

Raw Diluted

Low Dilution Ratio High

Particle Loss <2%

PMP limit = 90%

Penetration = Concentration after SPCS x DR Raw Concentration Before SPCS X 100

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0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000

0 50 100 150 200 250

Time (sec)

Particle number

Before ET After ET

30nm30nm：：>99%>99%

0 10 00 20 00 30 00 40 00 50 00 60 00 70 00 80 00 90 00 1 00 00

0 5 0 1 00 1 50 2 00 25 0

Time (sec )

Particle Number

Be fo re ET Afte r ET

50nm50nm：：_>99%>99%

0 1 0 0 0 2 0 0 0 3 0 0 0 4 0 0 0 5 0 0 0 6 0 0 0 7 0 0 0 8 0 0 0 9 0 0 0 1 0 0 0 0

0 5 0 1 0 0 1 5 0 2 0 0 2 5 0

T i m e ( s e c )

Particle Number

Be fo r e ET Af t e r ET

100nm 100nm：：>99%_>99%

0 50 100 150 200 250

30 50 100

Size [nm]

Temperature [C]

Minimum Temp. to remove C40 particles Minimum Temp. to remove C40 particles

C40 conc. 10⁴#/cc DR_PND2＝ 24.5 RE > 99%

ET Temp: 320 ET Temp: 320℃℃

C40 C40 （（ Tetracontane Tetracontane ）） Particle Removal Efficiency Particle Removal Efficiency

Consecutive measurements of diesel vehicle Consecutive measurements of diesel vehicle

0.0E+00 2.0E+06 4.0E+06 6.0E+06 8.0E+06 1.0E+07 1.2E+07 1.4E+07 1.6E+07 1.8E+07 2.0E+07

0 50 100 150 200 250 300

Time [s]

Solid particle concentration in CVS [part/cc]

-150 -100 -50 0 50 100

Speed [km/h]

Day I, Conc Day II, Conc Day III, Conc Day I, Speed Day II, Speed Day III, Speed

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Future Regulation R&D application

Variation (COV%)

Proposed SPCS ^Mass 6.8%

3.6%

>30%

Mass vs. Number

Golden Car: NEDC PM Mass

Number

SPCSProposed Proposed 2

Conclusion Conclusion

Gravimetric techniques continue to be employed in the industry

However, subject to issues related to ultra-low mass measurement

–Gas HC artifact, electro static force, etc.

Recent Topics in Diesel Engine Emission Measurement