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Conformity of Production Testing for Particle Traps - a Model ExperimentKasper. M., Mosimann. T.
Currently, Type Approval of new DPF systems is covered by acknowledged standards,such as the VERT protocol or the CARB certification procedure. While Type Approvaldemonstrates the quality of a single product sample (or a very limited number), itremains the manufacturer's responsibility to ensure that mass-produced units have -within narrow limits - exactly the same properties as the approved specimen. Theconformity of DPF substrates with their Approved Type is best demonstrated with ameasurement of particle precipitation efficiency.For this purpose, a model set-up for conformity of production (CoP) testing was realised,consisting of a soot particle generator and several particle measuring instruments; twolight-duty particle traps were mounted onto this model test rig and characterised.Measurements were carried out before and after DPF regeneration; then, holes weredrilled into the plugged filter channels to simulate defects.Particle concentrations downstream of the DPF units were found to be far below ambientconcentrations as long as the filters were intact. After regeneration, particle emissionswere observed to shortly increase by approximately two orders of magnitude, but theyreturned to low levels within a few minutes. With a defect of less than 1 mm2 in place,the filtration efficiency dropped from >99.995% to ~99%, further dropping as the size ofthe defect was increased, but independent of exhaust gas flow direction.The model experiment demonstrates the applicability of particle based measuringmethods to the challenge of CoP testing for DPF substrates.
N a n o p a r t i c l e M a n a g e m e n t
Matter Engineering
www.matter-engineering.com
Conformity of Production Testing for Particle Traps - a Model Experiment
Markus Kasper and Thomas MosimannMatter Engineering AG, Wohlen, Switzerland
background• DPF type approval established (e.g. VERT)• DPF market and production grow fast• quality control at end of production needed• conformity of production with approved specimen required
(e.g., 2007 FOEN Filter List)
• CoP testing should use diesel-like particles• particle measurement must be reliable even at post-DPF
concentrations• CoP method must be simple, reproducible, reliable
SiC based filter structure
CoP test set-up
• REXS soot generator
• MD19-2E diluter• SMPS, DiSC, PAS, DC
• DPF samples
summary
• CoP testing possible with compact set-up
• typical DPF penetration < 0.001%
• measurable with nanoparticle (standard) equipment
• even small defects increase penetration significantly
• particle penetration increases almost linearly with leak cross section area
• no effect of leak location in DPF sample
• distinction of smallest defects in new DPF substrate?
results - DPF ok
• DPF in normal condition: used, no defects
• particle penetration < 0.001%
Total Concentration: Before filter After filter Penetration Deposition
[-] [%]
Concentration [1/cm3] 8.03E+07 2.28E+03 0.000028 99.9972
DiSC Mean [1/cm3] 5.94E+07 1.13E+03 0.000019 99.9981
Stdv. [%] 1.02 253.64
PAS2000 Mean [µgEC/m3] 1.96E+05 6.31 0.000032 99.9968
Stdv. [%] 2.38 1.15
LQ1-DC Mean [µm2/cm3] 39.1
Stdv. [%] 46.62
SMPS
Measurement 1 - DPF Test using REXS Soot generator
Filter: FAP/Citroen, delivery condition, used, no defects
Measurement with SMPS, DiSC, PAS2000 and LQ1-DC
0.0E+0
2.0E+7
4.0E+7
6.0E+7
8.0E+7
1.0E+8
1.2E+8
10 100 1000diameter [nm]
0.0E+0
5.0E+3
1.0E+4
1.5E+4
2.0E+4
2.5E+4
3.0E+4
3.5E+4
4.0E+4
1. Sample
2. Sample
3. Sample
co
nc.
dN
/dlo
gD
p [
cm
-3]
SMPS Spectrum
after filterbefore filter
0.00001
0.00010
0.00100
0.01000
0.10000
1.00000
10 100 1000diameter [nm]
penetr
ation [-]
SMPS Penetration
N a n o p a r t i c l e M e a s u r e m e n t
Matter Engineering AG
0.0E+0
5.0E+3
1.0E+4
1.5E+4
2.0E+4
2.5E+4
0 100 200 300 400 500 600Time [s]
0
20
40
60
80
100
120PAS2000 [ugEC/m3]
LQ1-DC [um2/cm3]
Sensor signals: Measurement over time after DPF- DiSC [1/cm3]
0.000001
0.000010
0.000100
0.001000
0.010000
0.100000
1.000000
0 100 200 300 400 500 600Time [s]
DiSC
PAS2000 [ugEC/m3]
Sensor signals: Penetration
Measurement1-Citroen.xls Anhang 1
• DPF in normal condition: regenerated, no defects
• particle penetration < 0.001%
• note "refill" period (3 min)!
Total Concentration: Before filter After filter Penetration Deposition
[-] [%]
Concentration [1/cm3] 8.03E+07
DiSC Mean [1/cm3] 5.94E+07 5.88E+02 0.000010 99.9990
(last 5min) Stdv. [%] 1.02
PAS2000 Mean [µgEC/m3] 1.96E+05 7.52 0.000038 99.9962
(last 5min) Stdv. [%] 2.38
LQ1-DC Mean [µm2/cm3] 0.3
(last 5min) Stdv. [%]
SMPS
Measurement 3 - DPF Test using REXS Soot generator
Filter: FAP/Citroen, filter directly after regeneration, no defects
Measurement with SMPS, DiSC, PAS2000 and LQ1-DC
0.0E+0
2.0E+7
4.0E+7
6.0E+7
8.0E+7
1.0E+8
1.2E+8
10 100 1000diameter [nm]
0.0E+0
5.0E+3
1.0E+4
1.5E+4
2.0E+4
2.5E+4
3.0E+4
3.5E+4
4.0E+4
1. Sample
2. Sample
3. Sample
conc. dN
/dlo
gD
p [cm
-3]
SMPS Spectrum
after filter,no SMPS data available due to problems with DMA
before filter
0.00001
0.00010
0.00100
0.01000
0.10000
1.00000
10 100 1000diameter [nm]
pe
ne
tra
tio
n [
-]
SMPS Penetration
N a n o p a r t i c l e M e a s u r e m e n t
Matter Engineering AG
0.0E+0
1.0E+5
2.0E+5
3.0E+5
4.0E+5
5.0E+5
6.0E+5
7.0E+5
0 100 200 300 400 500 600 700 800Time [s]
0
2000
4000
6000
8000
10000
12000
14000
PAS2000 [ugEC/m3]
LQ1-DC [um2/cm3]
Sensor signals: Measurement over time after DPF- DiSC [1/cm3]
Measurements recorded from start of charging with soot particles
0.000001
0.000010
0.000100
0.001000
0.010000
0.100000
1.000000
0 100 200 300 400 500 600 700 800Time [s]
DiSC
PAS2000 [ugEC/m3]
Sensor signals: Penetration
Measurement3-Citroen.xls Anhang 3
Defect Penetration Deposition
[mm2] [-] [%]
No defect 0.00 0.0000099 99.9990
1 defect channel 0.79 0.0008823 99.9118
2 defect channels 1.57 0.0019846 99.8015
4 defect channels 3.14 0.0040919 99.5908
Summary of DPF Test using REXS Soot Generator
Filter: FAP/Citroen, with various defects
Values from DiSC Sensor
Number concentration
2.43E+05
[1/cm3]
5.88E+02
5.25E+04
1.18E+05
N a n o p a r t i c l e M e a s u r e m e n t
Matter Engineering AG
0.000001
0.000010
0.000100
0.001000
0.010000
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50
DPF Penetrationen of defect cross section
penetr
ation
Defect cross section surface [mm2]
0.0E+00
5.0E+04
1.0E+05
1.5E+05
2.0E+05
2.5E+05
3.0E+05
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50
Defect cross section surface [mm2]
Num
ber
concentr
ation a
fter
DP
F [1/c
m3]
DPF Penetrationen of defect cross section
Nachtrag 1
results - DPF leaky
• leaky DPF: defect simul-ated by one 1 mm hole
• particle penetration > 0.1%
• leaky DPF: defect simul-ated by four 1 mm holes
• exhaust flow direction reversed
• particle penetration > 0.5 %
Total Concentration: Before filter After filter Penetration Deposition
[-] [%]
Concentration [1/cm3] 8.03E+07
DiSC Mean [1/cm3] 5.94E+07 5.25E+04 0.000882 99.9118
Stdv. [%] 1.02 5.16
PAS2000 Mean [µgEC/m3] 1.96E+05 208.66 0.001064 99.8936
Stdv. [%] 2.38 0.36
LQ1-DC Mean [µm2/cm3] 688.1
Stdv. [%] 2.41
SMPS
Measurement 4 DPF Test using REXS Soot generator
Filter: FAP/Citroen, 1 damaged channel (1* bored out d=1mm)
Measurement with SMPS, DiSC, PAS2000 and LQ1-DC
0.0E+0
2.0E+7
4.0E+7
6.0E+7
8.0E+7
1.0E+8
1.2E+8
10 100 1000diameter [nm]
0.0E+0
5.0E+3
1.0E+4
1.5E+4
2.0E+4
2.5E+4
3.0E+4
3.5E+4
4.0E+4
1. Sample
2. Sample
3. Sample
conc. dN
/dlo
gD
p [cm
-3]
SMPS Spectrum
after filter,no SMPS
data availabledue to problems
with DMA
before filter
0.00001
0.00010
0.00100
0.01000
0.10000
1.00000
10 100 1000diameter [nm]
pe
ne
tra
tio
n [
-]
SMPS Penetration
N a n o p a r t i c l e M e a s u r e m e n t
Matter Engineering AG
0.0E+0
1.0E+4
2.0E+4
3.0E+4
4.0E+4
5.0E+4
6.0E+4
7.0E+4
8.0E+4
0 100 200 300 400 500 600Time [s]
0
100
200
300
400
500
600
700
800
900
1000PAS2000 [ugEC/m3]
LQ1-DC [um2/cm3]
Sensor signals: Measurement over time after DPF- DiSC [1/cm3]
0.000100
0.001000
0.010000
0.100000
1.000000
0 100 200 300 400 500 600Time [s]
DiSC
PAS2000 [ugEC/m3]
Sensor signals: Penetration
Measurement4-Citroen.xls Anhang 4
Total Concentration: Before filter After filter Penetration Deposition
[-] [%]
Concentration [1/cm3] 8.03E+07 3.40E+05 0.004238 99.5762
DiSC Mean [1/cm3] 5.94E+07 2.78E+05 0.004678 99.5322
Stdv. [%] 1.02 3.60
PAS2000 Mean [µgEC/m3] 1.96E+05 1015.19 0.005176 99.4824
Stdv. [%] 2.38 0.28
LQ1-DC Mean [µm2/cm3] 3440.8
Stdv. [%] 2.25
SMPS
Measurement 7 - DPF Test using REXS Soot generator
Filter: FAP/Citroen, 4 damaged channels, reverse flow
Measurement with SMPS, DiSC, PAS2000 and LQ1-DC
0.0E+0
2.0E+7
4.0E+7
6.0E+7
8.0E+7
1.0E+8
1.2E+8
10 100 1000diameter [nm]
0.0E+0
1.0E+5
2.0E+5
3.0E+5
4.0E+5
5.0E+5
6.0E+5
7.0E+5
8.0E+5
1. Sample
2. Sample
3. Sample
conc. dN
/dlo
gD
p [cm
-3]
SMPS Spectrum
after filterbefore filter
0.00001
0.00010
0.00100
0.01000
0.10000
1.00000
10 100 1000diameter [nm]
pe
ne
tra
tio
n [
-]
SMPS Penetration
N a n o p a r t i c l e M e a s u r e m e n t
Matter Engineering AG
0.0E+0
5.0E+4
1.0E+5
1.5E+5
2.0E+5
2.5E+5
3.0E+5
3.5E+5
0 100 200 300 400 500 600 700Time [s]
0
500
1000
1500
2000
2500
3000
3500
4000
PAS2000 [ugEC/m3]
LQ1-DC [um2/cm3]
Sensor signals: Measurement over time after DPF- DiSC [1/cm3]
0.001000
0.010000
0.100000
1.000000
0 100 200 300 400 500 600 700Time [s]
DiSC
PAS2000 [ugEC/m3]
Sensor signals: Penetration
Measurement7-Citroen.xls Anhang 7
Reproducible EXhaust Simulator - REXS
• combustion soot generator• 1.5 g/h @ 80 nm / 700 l/min • 65 / 80 / 100 nm mode• backpressure proof up to 500 mbar
Diffusion Size Classifier - DiSC
• on-line measurement of number and size• size range 10-300 nm• portable, 10 hrs battery operation• USB or bluetooth connectivity
Test Set-up:
For photo of Test Set-up, see Appendix 9
acknowledgment
This case study was financially supported by the AKPF - Association of Filter Manufacturers, www.akpf.org
The authors further wish to express their gratitude to Mr. Mayer, TTM, for many fruitful discussions.
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