Matter Engineering

Efficiency of Aftertreatment Devices of the Transantiago Bus Retrofit Project

Markus KasperMatter Engineering, Co. Ltd

A.R. ReinosoMTT, Santiago de Chile

9th ETH Conference on Combustion Generated Nanoparticles

ETH Zurich, August 15-17, 2005

Matter Engineering

Transantiago Filter Efficiency Measurement

• Dilution and Conditioning

• Particle Characterisation

• Application: DPF Characterisation

2

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Coagulation: Number Decreases, Size Increases with Time

N(t) = N0 / (1 + N0K0t) Dp(t) = Dp, 0 * (1 + N0K0t)1/df

W. C. Hinds (1999) "Aerosol Technology"

108 cm-3

100 nm

10-3 10-2 10-1 100 101 102 103105

106

107

108

109

50

100

150

200

time [sec]

N [cm

-3]

time [sec]

Dp [nm

]

105 nm

9.1·107 cm-3

10-3 10-2 10-1 100 101 102 103105

106

107

108

109

50

100

150

200

time [sec]

N [cm

-3]

time [sec]

Dp [nm

]

5.0·107 cm-3

141 nm

9.1·105 cm-3

10-3 10-2 10-1 100 101 102 103105

106

107

108

109

50

100

150

200

time [sec]

N [cm

-3]

time [sec]

Dp [nm

]

105.5 nm

9.0·105 cm-3

dilution 1:100

3

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Rotating Disc DiluterRevolving Door for Aerosol Particles

heated block80/120/150 ˚C

variable dilution1:15 ... 1:3'000

dilution air(pre-heated)

from tailpipe

to vent /peristaltic pump

to instruments

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Nucleation after DPF

Ricardo Consulting Engineers 2004

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Gravimetric Samples Before/After Trap

Hansen, Jensen, Ezerman (2001) Report 270-1-0019, Engine Technique Aarhus

0.05 g/KWh

0.07 g/KWh

6

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Flow of Droplets Through Cold Tube

heat sink

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Evaporation of Volatiles in Heated Section

evaporation tube heat sink

Re-Nucleation

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No Re-Nucleation if Droplet Concentration is Low

evaporation tube heat sink

volatile materialremains in gas phase

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Combine Diluter+Heater to Remove Droplets from Aerosol Sample

exhaust withnano-droplets

sample with nano-droplets

only solid particles left

dilute evaporate

Matter Engineering

Transantiago Filter Efficiency Measurement

• Dilution and Conditioning

• Particle Characterisation

• Application: DPF Characterisation

11

Matter Engineering AG

DPF Testing Equipment - Set-Up

diluterevaporator PAS

DC

DMA

CPC

SMPS

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Good Particle Trap ⇔ Appropriate Methods

10 100 1000

mobility diameter [nm]

Mass: -95%Number: -95%

100 100010

Mass: -95%Number: -55%

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10 100 1000

103

105

107

mobility diameter Dp [nm]

part

icle

em

issi

on d

N/d

log

Dp [c

m-3

]

Resolution Limit Applied to DPF

10 100 1000

103

104

105

106

107

108

mobility diameter Dp [nm]

part

icle

em

issi

on d

N/d

log

Dp [c

m-3

]

EU3 emission

good DPF

bad DPF

PM resolution limit

~ Dp-3

Matter Engineering

Transantiago Filter Efficiency Measurement

• Dilution and Conditioning

• Particle Characterisation

• Application: DPF Characterisation

15

Matter Engineering

Matter Engineering

Filter Efficiency Measurement

before filter

after filter

– 99.95%

Matter Engineering

DPF Efficiency -

Snap Acceleration

=> 99.95%

0.0E+0

5.0E+2

1.0E+3

1.5E+3

2.0E+3

2.5E+3

0 20 40 60 80 100 120

concentr

ation d

W/d

logD

p [cm

-3]

soot (PAS)

surface (DC)before trap

0.0E+0

5.0E+0

1.0E+1

1.5E+1

2.0E+1

2.5E+1

3.0E+1

0 20 40 60 80 100 120

concentr

ation d

W/d

logD

p [cm

-3] soot (PAS)

surface (DC)downstream from trap

0.0001

0.001

0.01

0.1

1

0 20 40 60 80 100 120

penetr

ation

penetration = 1 - efficiency

3.7

E+

5

4.7

E+

5

ratio =

0.8

0.0E+0

5.0E+4

1.0E+5

1.5E+5

2.0E+5

2.5E+5

3.0E+5

3.5E+5

4.0E+5

4.5E+5

5.0E+5

NanoM

et (P

AS

& D

C)

§

1.9

E+

2

2.2

E+

2

ratio =

0.9

0.0E+0

5.0E+1

1.0E+2

1.5E+2

2.0E+2

2.5E+2

NanoM

et (P

AS

& D

C)

§

0.0

53%

0.0

46%

0.0001

0.001

0.01

0.1

1

NanoM

et (P

AS

& D

C)

PAS DC ratio

PAS DC ratio

PAS DC

Workbook1

18

Filtration Efficiency Transantiago

Aftertreatment Licence plate Filtration

Adastra DPF VERT TF 52 04 99.909 %

Airmeex DPF VERT RR 15 47 99.377%

Engelhard DPF VERT NR 43 62 98.249%

Engelhard DPF VERT TT 21 91 99.777%HJS DPF VERT TE 37 76 99.954%HJS DPF VERT TJ 92 89 98.588%

HJS DPF VERT VF 37 42 99.975%

Huss DPF VERT LD 85 23 99.998%

Huss DPF VERT SZ 58 75 99.994%

Sudchemie DOC ZU 25 82 4.402%

Bekaert * DPF UK 83 19 39.942%ETG * DPF UY 52 02 34.143%

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Summary

• Controlled sampling is essential for particle measurement– separate solid particles from volatile nano-droplets

– freeze coagulation by early high dilution

• High-quality DPF require appropriate method– simple mass measurement leads to incomplete/wrong conclusions– size resolved number measurement provides valuable information

– fast measurement is possible at limited loss of information

• Good DPF reduce particles of any size by >99%– lower reduction rates should not be accepted by the user

20