Summary of Swedish Experiences on CNG and 'Clean' …energy.gov/sites/prod/files/2014/03/f9/deer_2003_ahlvik.pdf · Summary of Swedish Experiences on CNG and ”Clean” Diesel Buses

20032003--0808--2626 CNG and diesel busesCNG and diesel buses 11

Summary of Swedish Experiences on CNG and ”Clean” Diesel Buses

DEER 2003, August 24-28

Peter Ahlvik, Ecotraffic ERD3 AB

20032003--0808--2626 CNG and diesel buses 22 EcotrafficEcotrafficEcotrafficEcotrafficEcotrafficEcotrafficEcotrafficEcotraffic

Acknowledgements

Pär Gustafsson and Olle Hådell, the Swedish National Road AdministrationMats Wallin and Charlotta Sandström, AVL MTC in SwedenJohn Fairbanks, DOE


Outline

Introduction– Swedish auto ind.– Background

Regulations and incentives– SLTF vs. US & EU– Current bus fleet

Methodology– Data collection– Engine &

aftertreatment– Driving cycles

Results– NOX emissions – PM emissions– Formaldehyde– Benzene– 1,3-Butadiene– PAH– Cancer risk

DiscussionSummary & conclusions


Swedish automotive industry today

Annual production of heavy-duty vehicles >16 tons

119

337

115

571

61 1

26

45 1

96

43 4

65

33 6

76

23 8

99

11 5

21

020 00040 00060 00080 000

100 000120 000140 000

Volvo DCPacca

rMAN

ScaniaIveco

Navistar

HinoAnn

ual p

rodu

ctio

n (#

/yea

r)

Source: BIL Sweden

owned by

owned by


Background

First large fleet of ethanol buses in 1989 (Stockholm)Introduction of ultra-low sulfur diesel fuel in 1990 & “low-emission” diesel (i.e. ~Euro II) with ox catCNG buses in 1992 (Gothenburg); later also biogasRetrofit particulate filters (i.e. CRTTM) in mid 1990’sEnvironmental zones in larger cities (PM, HC and in 2nd

stage also NOX), 1996 (1st stage), 2002 (2nd stage)Retrofit EGR system with particulate filter in 1998Purchase recommendations by The Swedish Public Transport Association (SLTF) for bus fleets in 2001. Three levels for NOX and PM: base, rural and city.


NOX regulations for HD busengines in EU and USA vs. SLTF

0

1

2

3

4

5

6

7

8

9

1994 1996 1998 2000 2002 2004 2006 2008 2010 2012Year

NO

X e

mis

sion

s (g/

kWh)

EUUSASLTF City

Driving cycles:Driving cycles:

USA: US TransientUSA: US TransientEU: ETC & ECE R49EU: ETC & ECE R49

--87 %87 %

0,270,27

2,02,02,32,3


PM regulations for HD busengines in EU and USA vs. SLTF

0,00

0,05

0,10

0,15

0,20

0,25

0,30

0,35

0,40

1994 1996 1998 2000 2002 2004 2006 2008 2010 2012Year

PM e

miss

ions

(g/k

Wh)

EUUSASLTF City

Driving cycles:Driving cycles:

USA: US TransientUSA: US TransientEU: ETC & ECE R49EU: ETC & ECE R49

--55 %55 %

0,0130,013

0,0250,0250,020


Current fleet of transit buses inSweden (Sept. 2001); total 7789

3032

1 772

2 138

135362 248

92 0 100

500

1 000

1 500

2 000

2 500

3 000

3 500

Uncontr.Ox cat DPF

DPF & EGR

EtOH, ox cat

CNG, ox cat

CBG, ox cat EEV HEV

# of

bus

es

Alternative fuels and otherDiesel

Source: SLTF


Methodology

Collection of data on emissions, fuel production, etc. Baseline: Diesel Euro II engine, Swedish EC1 fuelDiesel aftertreatment: catalyst, DPF and DPF+EGR. Corrections for catalyst and DPF aging (diesel) Methane engine: SI (Otto), lean-burn w/, catalyst. Swedish results are grouped (average & BAT)Test cycles: Swe: Braunschweig, US: CBD, CSHVC. Corrections applied (CO2, diesel) for US tests.Comparisons of some selected emission results: Swe vs. US. Comparisons of cancer risk estimations.


Options to reduce the exhaustemissions from in-use diesel engines


The DNOx(TM) system from STTA retrofit and OEM EGR system

EGR valveEGR valve

PM filterPM filter

EGR cooler EGR cooler (hidden)(hidden) Control Control

unit (ECU)unit (ECU)

EGR pipeEGR pipe

Photo courtesy of STT Emtec


Engine technology forheavy-duty CNG engines

TWC Lean-burn DFNG

PING DING (PI) DING (GP)


Test cycles for transit buses

0

20

40

60

80

0 300 600 900 1200 1500 1800Time (s)

Spee

d (k

m/h

)

0

3

6

9

12

Dis

tanc

e (k

m)

SpeedDistanceBraunschweig cycle

0

20

40

60

80

0 300 600Time (s)

Spee

d (k

m/h

)

0

3

6

9

12

Dis

tanc

e (k

m)

SpeedDistance

CBD cycle

0

20

40

60

80

0 300 600 900 1200 1500 1800Time (s)

Spee

d (k

m/h

)

0

3

6

9

12

Dis

tanc

e (k

m)

SpeedDistanceCSHVC cycle


NOX emissions (g/km)

10,7

14,8

9,8

13,7

10,6

7,02

5,61

13,814,2

10,311,3

5,46

7,076,316,05

2,84

5,84

0

2

4

6

8

10

12

14

16

Swe_CD

BP_ECD1

SwRI_CDSwe_Cat

ARB_Cat

Swe_DPF

Swe_DPF+EGR

ARB_DPFBP_DPF

SwRI_LED

ARB_CNG-3

BP_CNG2

SwRI_CNG

Swe_Meth_avg

Swe_Meth_BAT

ARB_CNG-3

ARB_CNG-CW

NO

X e

miss

ions

(g/k

m)

CNG w/ catCNG w/oDiesel w/ DPFDiesel w/ catDiesel w/o

Diesel w/o Diesel w/ cat Diesel w/ DPF CNG w/ catCNG w/o


Particulate emissions (g/km)

0,20

0,150,13

0,054

0,17

0,0070,017

0,0030,0060,020

0,036

0,0020,013 0,0090,0090,0150,015

0,00

0,05

0,10

0,15

0,20

0,25

Swe_CD

BP_ECD1

SwRI_CDSwe_Cat

ARB_Cat

Swe_DPF

Swe_DPF+EGR

ARB_DPFBP_DPF

SwRI_LED

ARB_CNG-3

BP_CNG2

SwRI_CNG

Swe_Meth_avg

Swe_Meth_BAT

ARB_CNG-3

ARB_CNG-CW

Part

icul

ate

emiss

ions

(g/k

m)




Formaldehyde emissions (mg/km)

29,0

18,8

7,3

0

14,5

3,60,10,2

2,92,9

391 258 348

25,8

17,5

7,3

14,7

0

5

10

15

20

25

30

35

40

45

50

Swe_CD

SwRI_CD

ARB_Cat

Swe_DPF+EGRBP_DPF

ARB_CNG-3

SwRI_CNG

Swe_Meth_BAT

ARB_CNG-CW

Form

alde

hyde

em

issi

ons (

mg/

km) CNG w/ cat

CNG w/oDiesel w/ DPFDiesel w/ catDiesel w/o



Benzene emissions (mg/km)

0

3,27

0,57

2,00

1,18

0,60

0,080,27

0,600,60

2,99

0,67

1,02

0,59

0,27

0,60

1,20

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

Swe_CD

SwRI_CD

ARB_Cat

Swe_DPF+EGRBP_DPF

ARB_CNG-3

SwRI_CNG

Swe_Meth_BAT

ARB_CNG-CW

Ben

zene

em

issi

ons (

mg/

km)




1,3-Butadiene emissions (mg/km)

0,000,00

17,4

0,00

5,22

0,910,000,00

6,966,96

3,13

0,000,18 0,000,00

10,0

20,0

0

4

8

12

16

20

24

Swe_CD

BP_ECD1

SwRI_CD

Swe_Cat

ARB_Cat

Swe_DPF

Swe_DPF+EGR

ARB_DPF

BP_DPF

SwRI_LED

ARB_CNG-3

BP_CNG2

SwRI_CNG

Swe_Meth_avg

Swe_Meth_BAT

ARB_CNG-3

ARB_CNG-CW

1,3-

But

adie

ne e

mis

sion

s (m

g/km

) CNG w/ catCNG w/oDiesel w/ DPFDiesel w/ catDiesel w/o



12 species of tri+ PAH emissionsfor some selected tests

4085

9,22181

139

595

232,4

379

0

100

200

300

400

500

600

700

EPEFE EC1w/o aft

w/ catw/ DPF CD

LEDCNG

CNGCBG

PAH

em

issi

ons

( µg/

km)

Tests at SwRITests at MTC

Diesel truck w/o Diesel buses CNG/CBG buses


Cancer risk index (diesel=100)Base case (T&E URFs)

0

20

40

60

80

100

120

Diesel Diesel, cat

Diesel, DPF

Diesel, EGR+DPFMethane "av."

Methane "BAT"

Can

cer

risk

inde

x (d

iese

l = 1

00) PAC

AldehydesAlkenesBenzeneParticulates

Unit risk factors (URFs) byTörnqvist & Ehrenberg

CNGDiesel Euro II

100100

6262

1717 1717

2727

4747


Cancer risk index (diesel=100)URFs by US EPA 1990

0

20

40

60

80

100

120

Diesel Diesel, cat

Diesel, DPF


Methane "BAT"

Can

cer

risk

inde

x (d

iese

l = 1

00) PAC


URFs by US EPA 1990

Alternative fuelsDiesel Euro II

100100

6969

1818 17172222

3838


Cancer risk index (diesel=100)URFs by OEHHA, case #1

0

20

40

60

80

100

120

Diesel Diesel, cat

Diesel, DPF


Methane "BAT"

Can

cer

risk

inde

x (d

iese

l = 1

00) PAC


URFs by OEHHA, but* PM only for diesel* Alt. fuels w/o PM

Alternative fuelsDiesel Euro II

100100

8585

1010 8,38,33,13,16,16,1


Cancer risk index, four chemicalspecies only (URFs by OEHHA)

0

10

20

30

40

50

60

70

80

90

100

110

Swe_CD

BP_ECD1

SwRI_CD

Swe_Cat

ARB_Cat

Swe_DPF

Swe_DPF+EGR

ARB_DPF

BP_DPF

SwRI_LED

ARB_CNG-3

BP_CNG2

SwRI_CNG

Swe_Meth_avg

Swe_Meth_BAT

ARB_CNG-3

ARB_CNG-CW

Can

cer

risk

inde

x (d

iese

l=10

0)

AcetaldehydeFormaldehyde1,3-ButadieneBenzene


100

2,06,9

31,737,8

1,1

37,8

0,3 0,15,6

76,1

84,8

48,9

108,8

54,4

4,7 6,0


Cancer risk index, four chemicalspecies and PM (URFs by OEHHA)

0

10

20

30

40

50

60

70

80

90

100

110

Swe_CD

BP_ECD1

SwRI_CD

Swe_Cat

ARB_Cat

Swe_DPF

Swe_DPF+EGR

ARB_DPF

BP_DPF

SwRI_LED

ARB_CNG-3

BP_CNG2

SwRI_CNG

Swe_Meth_avg

Swe_Meth_BAT

ARB_CNG-3

ARB_CNG-CW

Can

cer

risk

inde

x (d

iese

l=10

0)

AcetaldehydeFormaldehyde1,3-ButadieneBenzeneParticulates


100

69,661,1

82,3

11,4

25,7

9,93,1 1,3 3,6

9,9

21,5

3,4

12,7 9,94,6 4,8


Conclusions 1(2)

Regulations and incentives are importantTransit buses in larger cities use ULSD and DPF/DPF+EGR or alt. fuels with ox. catalystNOX is fairly similar for US & Swe. CNG has lower NOX than diesel but is matched by EGR. NOX affected by driving cycle “optimization”?PM is generally higher for Euro II than US -98. CNG and diesel with DPF are roughly similar.Very high formaldehyde level for CNG w/o cat. No Swedish results for CNG w/o catalyst (!!!)


Conclusions 2(2)

Benzene is fairly low for both fuels; impact of cat1,3-Butadiene results are inconsistentURFs has considerable impact on cancer riskFormaldehyde and 1,3-butadiene most important chemical species with OEHHA URFsPM is of great importance with OEHHA URFs. What is the impact of PM from alternative fuels?Importance of PAH (PAC)?The emission technology applied may be of greater importance than the fuel choice


This concludes my presentation

Thank you for your attention!Questions?

More information available at: www.ecotraffic.se

www.vv.se(e.g. reports, presentations, etc.)

Documents

Summary of Swedish Experiences on CNG and 'Clean' …energy.gov/sites/prod/files/2014/03/f9/deer_2003_ahlvik.pdf · Summary of Swedish Experiences on CNG and ”Clean” Diesel Buses