EVALUATION OF THE EUROPEAN PMP METHODOLOGIES USING CHASSIS

DYNAMOMETER AND ON-ROAD TESTING OF HEAVY-DUTY VEHICLES

Thomas D. Durbin, Kent C. Johnson, Heejung

Jung, Ajay Chaudhary, and David R. Cocker IIICollege of Engineering-Center for Environmental Research and Technology

(CE-CERT), University of California, Riverside

Jorn

D. Herner, William H. Robertson,Tao

Huai

and Alberto AyalaCalifornia Air Resources Board

(CARB)

David KittelsonDepartment of Mechanical Engineering, University of Minnesota

Diesel Engine Efficiency & Emissions Research ConferenceAugust 4-7, 2008

Overview•

Background

•

Objectives•

Experimental setup

•

Results–

Integrated data

–

Real time data•

Conclusion

www.cert.ucr.edu

Background•

Current gravimetric method have increasing difficulty quantifying post-DPF PM mass emissions accurately.–

Background contribution

–

Insensitive to DPF fill state

•

Euro 5/6 standard includes measurement of solid particles (>23nm) as an additional new metric of particles emitted from light-duty diesel vehicle.

Objectives

•

Critical evaluation of the proposed European PMP method for determining particle emissions from heavy-

duty diesels and its potential in California for PM measurement and in-use screening.

•

Evaluate PMP under both laboratory and on-road conditions.

•

Particle mass

vs

particle number.

Courtesy of W. Robertson at CARB

Gravimetric vs

PMP measurements

CVSBlower

2.5 um size cut

Secondary dilution

Pump

Filter sampling system

2.5 um size cut

Primary dilutionat PMP (150 ̊C)

Secondary dilutionat PMP

Evaporation tube(300 ̊C)

Condensation particle counter(cut-off at 23nm)

Vehicleexhaust

Courtesy of W. Robertson for MD-19 diagram

Golden systemClone PMP system

TSI 3790

Experimental conditionsLab test On-road test

Base Chassis dynamometer Mobile Emission Lab

PMP system Clone system Clone & Alternative (ISO 8178) systems

Vehicle 1999 International 4900 Freightliner class 8

Engine International DT 466E (7.6L) Caterpillar C-15 (14.6L)

Fuel ULSD ULSD

Lube oil SAE 15W-40 SAE 15W-40

DPF Engelhard DPX JM CRT

Vehicle weight 27,000 lb 65,000 lb

Cycles 2x UDDS (35 min)50 mph Cruise (45 min)Idle (40 min)

UDDS (18 min)ETC Cruise (10 min)CARB Creep (4 min)Flow-of-traffic

www.cert.ucr.edu

Lab testing (at CARB MTA lab)

UCR/CE-CERT’s

Mobile Emission Lab (MEL) for On-Road Testing

Diluted Exhaust: Temperature, Absolute Pressure, Throat ΔP, Flow.

Gas Sample Probe.

Secondary Dilution System* PM (size, Mass).

Drivers Aid.

CVS Turbine: 1000-4000 SCFM, Variable Dilution.

Gas Measurements: CO2 %, O2 %, CO ppm, NOx ppm, THC ppm, CH4 ppm. Other Sensor: Dew Point, Ambient Temperature, Control room temperature, Ambient Baro, Trailer Speed (rpm), CVS Inlet Temperature.

Engine Broadcast: Intake Temperature, Coolant Temperature, Boost Pressure, Baro Pressure, Vehicle Speed (mph), Engine Speed (rpm), Throttle Position, Load (% of rated).

Dilution Air: Temperature, Absolute Pressure, Throat ΔP,Baro (Ambient), Flow, Dew Point (Ambient).

Secondary Probe.

GPS: Pat, Long, Elevation, # Satellite Precision.

Exhaust: Temperature, ΔP (Exhaust-Ambient), Flow.

Cocker et al. Environ. Sci. Technol. 2004, 38, 6809-6816

Flow diagram of PM measurement system

CVS Filter sampling train (gravimetric)

PMP diluter TSI 3790 CPC (23 nm)TSI 3025 CPC (3 nm)

TSI 3022 CPC (7 nm)TSI 3025A CPC (3 nm)

Primarydilution

Secondarydilution

Sampling & Measurement

MEL CVS MEL secondary diluter Filter sampling train (gravimetric)

PMP diluter(Clone system)

TSI 3790 CPC (23 nm)TSI 3760 CPC (11 nm)TSI 3025 CPC (3 nm)

PMP diluter(Alternative system)

TSI 3760 CPC (11 nm) TSI 3025 CPC (3 nm)

TSI 3022 CPC (7 nm)

Primarydilution

Secondarydilution

Sampling & MeasurementOn-road test

Lab test

F-SMPS and EEPS at MEL CVS and PMP diluter

(Clone system)PMP CPC

PMP CPC

Integrated Results (using Clone PMP system)

PM mass (from gravimetric method)

www.cert.ucr.edu

-5

0

5

10

15

20

25

30

Cruise Double UDDS

Idle ETC Urban

ETC Cruise

ARB Creep

UDDS Route 1

PM (m

g/m

i), (m

g/hr

) for

Idle

Lab test On-road test

-5

0

5

10

15

20

25

30

ETC Urban ETC Cruise ARB Creep UDDS Route 1

PM (m

g/hp

-hr)

2007 Emission Standard 10 mg/hp-hrfor an FTP Engine Dynamometer Test

2007 In-Use Emission NTE 30mg/hp-hr

Cruise Double UDDS Idle ETC Urban ETC Cruise ARB Creep UDDS Route 1

PM M

ass

on F

ilter

(µg)

0

50

100

150200

250

On-road testLab test

3 × reference filter weight for on-road testing (3 × 2.5 = 7.5 µg)σ

PM number

* Means at VS and ** means at MEL PMP system

Cruise 2 UDDS ETC Urban ETC Cruise ARB Creep UDDS Route1 Route2

Parti

cle

coun

t (#/

mi)

1e+10

1e+11

1e+12

1e+13

1e+14

1e+15

1e+16

3790 (23nm)3025A (3nm)3022* (7nm)

Lab test On-road test

/mi)#10(8StandardDutyLight 5/6Euro

11⋅

ETC UrbanETC CruiseARB Creep UDDS Route 1 Route 2

Par

ticle

cou

nt (#

/hp-

h)

1e+10

1e+11

1e+12

1e+13

1e+14

1e+15

3790 (23nm) 3025A (3nm)

ETC UrbanETC CruiseARB Creep UDDS Route 1 Route 2

Par

ticle

con

cent

ratio

n (#

/cc)

1e+0

1e+1

1e+2

1e+3

1e+4

1e+5

1e+6

1e+7

3790 (23nm)3025A (3nm) 3022* (7nm)

PMP CPC

PMP CPC

PMP CPC

Coefficient of Variation (COV)

www.cert.ucr.edu

Cruise 2 UDDS ETC UrbanETC CruiseARB Creep UDDS

CO

V(%

)

0

50

100

150

200

250

300

3790 3025 3022* PM Mass

Lab test On-road test

**

(23nm)(3nm)(7nm)

Results (Real time data)

Concentrations normalized to those at CVS for comparison.

ETC (European Transient Cycle)

European Transient Cycle (ETC) CruiseA spike showed up in the beginning of ETC cruise cycles all the time due to gear shift before the cycle.

Time (hh:mm:ss)

11:57:00 12:02:00 12:07:00

dN/d

logD

p (#/cm

3 )

789

20

30

40

50

60708090

200

10

100

1e+2 1e+3 1e+4 1e+5 1e+6 1e+7

CPCs

Under PMP F-SMPS at CVS

0

50

100

150

200

250

300

350

400

450

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

1.00E+07

1.00E+08

600 700 800 900 1000 1100 1200

Exha

ust t

empe

ratu

re (C

)

Part

icle

con

cent

ratio

n (#

/cc)

Cycle time (s)

3025 (3nm)

3022* (7nm)

3760 (11nm)

3790 (23nm)

EEPS (6nm)

Exh_temp_C

Dp(

nm)

3 hypotheses: • Solid particle penetration-

-> Size distribution from previous studies using EEPS and DMS-> Need to confirm with f-SMPS or nano-SMPS-> Continuous ash particle emissions at DPF?-> Unlikely

• Partial evaporation of large particle• Re-nucleation of sulfate

Driving cycle (UDDS)

UDDS (Schedule D)

0

5

10

15

20

25

30

35

40

45

50

55

60

0 100 200 300 400 500 600 700 800 900 1000 1100Time - seconds

Vehi

cle

Spee

d - m

ph

US EPA Urban Dynamometer Driving Schedule (UDDS)

Time (s)

0 200 400 600 800 1000

Parti

cle

Size

, Dp

(nm

)

789

20

30

40

50

60708090

200

10

100

1e+2 1e+3 1e+4 1e+5 1e+6 1e+7

CPCs

under PMP F-SMPS at CVS

1.0E+02

1.0E+03

1.0E+04

1.0E+05

1.0E+06

1.0E+07

0 100 200 300 400 500 600 700 800 900 1000

part

icle

con

cent

ratio

n(#/

cc)

Cycle time (s)

3025 (3nm)

3022*(7nm)

3760 (11nm)

3790 (23nm)

Real time data (flow-of-traffic)

Comparison of MEL vs MD19 Dilution System For CPC's 3760 11nm and 3790 20nmNormalized to MD19 Dilution (MEL DR ~100 MD19 DR~300)

10

100

1000

10000

100000

0 50 100 150 200 250 300 350 400 450 500

Time (sec)

Part

icle

Cou

nt (#

/cc)

0

100

200

300

400

500

600

700

800

Engi

ne P

ower

(bhp

) Veh

icle

Spe

ed (m

ph)

CPC3760 MD19CPC3760 MELCPC3790 MD19Vehicle SpeedEng PowerExh Temp

Time (sec)

0 100 200 300 400 500

Part

icle

Siz

e, D

p (n

m)

789

20

30

40

5060708090

200

300

400

500

10

100

1e+4 1e+5 1e+6 1e+7 1e+8

CPCs

under PMP EEPS at CVS

Hydrated sulfate concentration contributes to 45% of mass

Conclusion•

The overall combined laboratory and on-road results indicate that particle number can provide a superior measurement for current wall-flow DPFs

with particle emission levels well below the 2007 US PM mass standard, but not necessarily at higher PM levels near the standards.

•

The DPF-equipped medium and heavy-heavy-duty-vehicle 3790 PMP number emissions are lower than the European light duty standard of 8.0 x 1011

#/mi. The emissions range from 6.7 x 1011

to 0.5 x 1011

#/mi depending on the cycle, vehicle/technology, and other test conditions used.

•

Under more aggressive, on-road driving conditions, significant nucleation was observed, indicated by very high count levels below the PMP system. These particles had a large sulfate contribution

indicating that the nucleation mode particles could be due to the conversion of SO2

to SO3

.

Conclusion•

The particle number measurements for the low cut point CPCs

below the PMP system were approximately an order of magnitude higher than those for the PMP-compliant CPC and the other high cut point CPCs

below the PMP system. This indicates the presence of a significant fraction of solid sub-23nm particles that are not being counted by the PMP approach. –

Advantage is nucleation particles that can contribute to variability are removed.

–

Disadvantage removes the ability to characterize very small particles that survive the heating in the VPR.

•

For the on-road tests, the coefficients of variation (COVs) for the particle number counts below the PMP were all lower than those for the PM mass measurements for nearly all testing scenarios.

•

For the laboratory tests, however, outliers were found on both the 50 mph cruise and the UDDS. The development of statistical techniques for the removal of outlier tests for particle number should be considered. Also, while the PM mass measurements have a lot of scatter at current wall-flow DPF tailpipe levels, the particle number measurements have outliers that can be removed using statistics.

www.cert.ucr.edu

Acknowledgements•

The funding for this research is from the California Air Resources Board (CARB)

under contract No. 05-320.

–

Dr. Marcus Kasper

of Matter Engineering Inc.–

Mr. Jon Andersson

of Ricardo–

Dr. Andreas Mayer of Technik

Thermischer

Maschinen

(TTM).–

for their assistance in developing the test plan procedures, in carrying out the experiments, and in analysis of the data.

–

Mr. Donald Pacocha, for his contribution in setting up and executing this field project, the data collection and quality control.

–

Joint Research Center (JRC)

of the European Commission–

The statements and opinions expressed in this presentation are solely the authors’

and do not represent the official position of the California Air Resources Board.

The mention of trade names, products, and organizations does not constitute endorsement or recommendation for use." We usually toss the disclaimer in at the bottom of the author list/acknowledgments.

•

Disclaimer -

The statements and opinions expressed in this presentation are solely the authors’

and do not represent the official position of the California Air Resources Board.

The mention of trade names, products, and organizations does not constitute endorsement or recommendation for use.

Thanks

www.cert.ucr.edu