development of vehicle emission factors using pems · volvo olympian euro ii dennis trident euro ii...

Development of vehicle

emission factors using

PEMS

Dr. Carol Wong Senior Environmental Protection Officer Environmental Protection Department

Hong Kong September, 2013

Outline

Background, Objective & Current Status

PEMS test procedures

Vehicle info and test set up

PEMS data analysis

Conclusion

2

Background & Objectives

EPD has adapted EMFAC developed by California Air Resources Board (CARB) into Hong Kong

Have been using US vehicle emission data in EMFAC-HK calibrated by our PEMS test data

Traffic conditions at busy corridors

• Being a metropolitan city, HK is very different from US or

Europe

• Wish to replace these emission data in EMFAC-HK by local

on-board emission data and also develop a microscopic

model

Various PEMS being used in HK

SEMTECH-DS

SEMTECH-SAMPS

SEMTECH-Filter Sys. SEMTECH-Low

CO analyzer

Micro-soot sensor

Gravimetric filter module

THC/low CO analyzer FTIR

Analyzers Measurement

SEMTECH-DS (7 units) CO, CO2, NO, NO2, THC

SEMTECH-ECOSTAR (1 unit)

(not yet working)

NO, NO2, PM

A&D portable FTIR (1 unit) N2O, NH3, CO, CO2, NO,

NO2, & various hydrocarbon

species

SECTECH-Low CO analyzers

(2 units)

CO in low concentration

A&D THC/Low CO analyzer

(1 unit) (not yet working)

CO in low concentration and

THC

SEMTECH-SAMPS (5 units) &

SEMTECH-Filter System (3

units)

PM

AVL M.O.V.E. PM PEMS (2 units) Real time PM

Current Status measuring real-world vehicular emissions using PEMS

since 2008 ◦ Collected about 14 million seconds of measurement data

◦ Tested about 180 vehicles

◦ Test each vehicle for all its business hours

◦ Emission standards: from pre-Euro to Euro V

26

20

10

4

51

31

25

6

0

10

20

30

40

50

60

No

. of

Veh

icle

s

Vehicle Types

Vehicles tested until end August, 2013

Vehicle

Class

Fuel

Type

Emission Standard

Total Pre-

Euro Euro I Euro II Euro III Euro IV

Euro

V

Cars Petrol 2 9 14 1 26

Taxis LPG 12 4 4 20

Mini buses LPG 6 4 10

Diesel 1 2 1 4

Truck ≤ 5.5 t Diesel 4 4 7 20 13 3 51

Truck > 5.5t Diesel 1 1 4 16 7 2 31

School Bus Diesel 1 1 2 4

Single Deck

Coaches Diesel 1 7 15 2 25

Double

Deck Buses* Diesel 4 2 6

Total 5 6 32 68 58 8 177

Vehicles Explored up to end Aug., 2013

* Double deck buses are retrofitted with diesel particulate filter (DPF).

6

Vehicle Class

Euro III Euro IV Euro V

Nil DOC

DOC

&

EGR

EGR DPF

DOC

&

EGR

POC

&

DOC,

EGR

DPF

DPF

&

EGR

SCR*

DOC

&

EGR

DPF

&

EGR

SCR

Mini buses 2 1

Truck <= 5.5 t 5 15 6 4 3 3

Truck > 5.5t 5 4 5 1 1 3 3 1 1 1

School Bus 2

Single Deck

Coaches 1 5 1 1 2 1 11 2

Double Deck

Buses (w DPF) 2

Total 6 11 27 2 3 10 7 2 6 11 1 4 2

Euro III, IV & V Diesel Vehicles

Explored up to end Aug., 2013

7 *The vehicle may also be fitted with DOC

Outline




PEMS data analysis

Conclusion

8

9

Test procedures

Follow most stringent testing requirements:

◦ ISO16183

◦ US CFR 1065 Subpart J

◦ EU JRC’s “Guide for the preparation and the

execution of emission road tests on heavy-duty

vehicles”

10

Test procedures

Perform zero every hour and audit of the

gas analyzers every three hours

Implement ‘duplication of measurements’

principle

Analyze 2-3 fuel samples from each test

vehicle’s fuel tank

On-Road Testing Example: SCR coach

• On-road testing of an EURO IV coach (w/

SCR)

• Professional bus drivers

• Driving on a pre-determined

routes as well as following a similar

vehicle

• 50-60% of maximum payload

• Traffic are captured by video

camera mounted in front of the

bus

• Both gaseous pollutants and PM are

collected

• PEMS used – SEMTECH-DS, FTIR,

and M.O.V.E. PM PEMS

Soot concentration from

AVL PM PEMS

Emission data from SCR vehicle testing

Outline




PEMS data analysis

Conclusion

12

Example: SCR retrofit program on 3 Double

Deck Buses (FBDD) with DPF

Make Dennis Trident

Euro III

Volvo Olympian

Euro II

Dennis Trident

Euro II

Eng Model ISMe 335 Euro

III/1-08-2003

D10A 245 M11-305E21

Eng Capacity 10.8 litre 9.6 litre 10.8 litre

Emi Standard Euro III Euro II Euro II

First Reg. Date 1 Aug 2003 10 Mar 1998 23 Sept 1998

Engine rated

power

246 kW @ 1900

RPM

180 kW @ 2000

RPM

224 kW @ 1900

RPM

Engine rated

torque

1410 Nm @

1200 RPM

1050 Nm @ 1450

RPM

1250 Nm @ 1250

RPM

GVW 23.5 tonnes 22.94 tonnes 23.1 tonnes

Loaded Weight 19.0 tonnes 19.7 tonnes 19.4 tonnes

After treat. device DPF DPF DPF

13

14

Test Set-up

15

Speedometer

GPS, RH &

temperature

sensors

15

Remote diluter

Exhaust flow meter

Heated line

Heated line for

sampling before SCR

SCR

Installation - 1

Connecting pipes

from tailpipe to PEMS

Installation - 2

Filter

system

FTIR

Heated line

SEMTECH-DS

Microdilution

system (MPS)

SEMTECH-

DS

Fixed Route Maps

17

Outline




PEMS data analysis

Conclusion

18

3 FBDD retrofitted with DPF+SCR :

Trip Avg Speed and Max Speed

19

urban highway

Euro II Dennis Trident FBDD w DPF: NOx Real-time snapshot

Base case

(with DPF)

Measured at the

position before

SCR

20

Measured at the

position after SCR

After retrofitted with SCR

Euro III Dennis Trident FBDD w DPF: NOx Real-time snapshot

Base case

(with DPF)

Measured at the

position before

SCR+DPF

21

Measured at the

position after

SCR+DPF

After DPF removal and retrofitted with SCR+DPF

Data Pre-Processing (Gaseous)

22

Data QA/QC Checks In order to perform the QA/QC task, a variety of plots

were created to expose outlying, unusual, or inaccurate data ◦ Exhaust flowrate distributions by vehicle

◦ Exhaust concentration distributions by vehicle

◦ Raw vs corrected exhaust concentrations by vehicle

◦ Maximum and mean exhaust concentrations by test, displayed together by vehicle

◦ Exhaust concentrations vs time by test

◦ VSP bin frequency and VSP binned emission mass rates by vehicle

data flags in SAS were used to draw attention to values that lie outside of expected ranges

Automatic Error detection Checking and calibrating speedometer

reading by GPS 1) Select the good GPS data by

extracting “Horizontal

dilution of ratio”< 1.3

2) Linear regression with

Speedometer data to

measure R2 and slope

3) Use the slope to calibrate

speedometer readings

Partial speedometer error Speedometer error Normal data

Automatic Error detection Abnormal jumps in

exh. temp.

Abnormally long

negative readings

Jumps in THC

readings Outliers in

NO readings

High THC peaks

Cold start

Drift in THC

QA/QC results

Heavy

diesel truck

> 15 t:

THC

emission

factors

Before data cleansing After data cleansing

Light diesel

truck <= 5.5 t:

NOx emission

factors

NOx emission rates (g/min)

Dennis Trident Euro III bus

retrofitted with DPF

Baseline

NOx emission rates (g/min)

Dennis Trident Euro III bus


1 month after retrofitted with

SCR+DPF

29

NOx emission factors (g/km)

Volvo Olympian Euro II bus


Baseline

30



retrofitted with DPF and SCR

1 month after SCR retrofit

Exhau

st t

em

p o

C

31

NOx emissions in g/km


retrofitted with DPF and SCR,

1 month after SCR retrofit with

traffic jam at Mongkok

Exhau

st t

em

p o

C

32



retrofitted with DPF and SCR,

6 month after SCR with low exhaust

temp (<=200oC)

Exhau

st t

em

p o

C

37

NO emissions of post-SCR at 6

months after SCR retrofit (blue

triangles) are close to base line

emissions (red triangles) and highly

fluctuating.

Description NO NO2 NOx

%reduction at 1 month after

SCR retrofit vs. baseline 73-85% 81-92% 74-86%

%reduction at 6 months after

SCR retrofit vs. baseline -14-50% 70-94% -2-56%



38

One trip for this FBDD has

urea shortage. The NO &

NO2 reductions are

particularly low.







SCR retrofit vs. baseline

(Excluding urea shortage trip)

64-70%

61 – 69%

(with one trip

35%)

64 – 68%

39

The NO reductions are very small at

6 months after the retrofit because

SCR had broken down due to

uncontrolled regeneration (green

triangles)






PM Emission Factors

Filter for other high

emitting vehicle

The color is white

even though PM

emissions are high

41

• Test trips with excessive idling can also introduce significant PM error

We have the following

criteria:

• abs(Intercept/ max.

sample flow) <= 5% (c.f.

ISO 16183: <= 2%)

• Std error/mean <= 10%

(c.f. CFR1065 <= 3.5%)

• Std error/max. <= 5%

(ISO16183: <= 5%)

• R2 >0.95 (c.f.

ISO 16183: >0.95)

Normal Situation

excessive idling

42

PM results for SCR Euro IV coaches > 15 t

Real time PM

Time (s)

Est

imat

ed P

M (

g/s)

AVL PM PEMS is capable to measure real time soot conc., and then estimate real

time PM emissions from soot, CO, CO2, THC conc. These real time PM

emissions are then calibrated by PM mass collected in the on-board filter.

These high

PM emissions

are due to

hard

accelerations

when the

vehicle

started.

PM emissions with Spd and CO High PM emission usually accompanied by hard accelerations

PM emission strongly correlated in time with CO emissions

1320 1350 1380 1410 1440 1470 1500 1530 1560 1590 1620 1650 1680Time [s]

mdo

t_PM

[g/s

]

-0.024

-0.016

-0.008

0.000

0.008

0.016

0.024

0.032

0.040

0.048

0.056

0.064

0.072

0.080

0.088

0.096

0.104

0.112

CO [%

]

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

1320 1350 1380 1410 1440 1470 1500 1530 1560 1590 1620 1650 1680Time [s]

mdo

t_PM

[g/s

]

-0.08

-0.06

-0.04

-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0.20

0.22

0.24

0.26

Veloc

ity [k

m/h

]

-40

-30

-20

-10

0

10

20

30

40

50

60

70

80

90

100

110

120

130

Outline




PEMS data analysis

Conclusion

45

Conclusion

The emission factors derived from the

on-board measurement data will be used

in EMFAC-HK

They will also be used in a microscopic

model for more refined traffic conditions

46

development of vehicle emission factors using pems · volvo olympian euro ii dennis trident euro ii...

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