Sensitivity and Reproducibility of Brake Wear Particle ...
Transcript of Sensitivity and Reproducibility of Brake Wear Particle ...
150th PMP Meeting 4th April 2019Brussels
Sensitivity and Reproducibility of Brake Wear Particle Emission Measurements
using JARI System
Hiroyuki HaginoJapan Automobile Standards Internationalization Center (JASIC)
Overview
Detection Sensitivity for PN and PM
Reproducibility of JARI Sampling System
Cycle Pattern Analysis for World Harmonization
Conclusions and Next Steps
Contents2
History of JARI Sampling System3
Stage 0 : JARI initial research for PM2.5 measurement
Stage I : JASO PM2.5 measurement with constant volume and isokinetic sampling
Stage II : World harmonization of PN and PM measurements
Stage 0︓PM2.5 CompositionEmission Estimation
Stage I︓PM2.5 Emission & CompositionJASO nomination at July 2019
Stage II︓PN & PM Emission
Issues for Cooling Brake System,
Sensitivity, etc.
Flow Rate 4 m3/min
PN Emission Level for Regenerative Brakebelow Detection Limit for PN
Cooling Brake Large Facility
High Flow Rate Low Sensitivity
Comparability Brake Wear Particles and Wear Mass (using Stage I) 4
There is a need to aim for Good Correlation with PM and Wear Mass
measurement system.But, the relationship should be depend on brake system.
PM10 vs. Wear Mass (Pad + Rotor)
Compromise Necessary !!
Overview
Detection Sensitivity for PN and PM
Reproducibility of JARI Sampling System
Cycle Pattern Analysis for World Harmonization
Conclusions and Next Steps
Contents5
Current Status of JARI Measurement System (Stage I) 6
Installable sampling system for pre-existing dyno.
PM2.5 measurement with constant volume and isokinetic samplingPMP cycle soak time: 10 min for time and cost saving only in this study
JARI Measurement System Push
Particle Free AirParticle Sampling
Pull
Air Flow Rate1 m3/min (Range 1–20 m3/min for Stage II)20 °C (Range 15–30 °C for Stage II)
RH < 35 % (Range 15–60% for Stage II)PM Measurement
Filter Sampling (PM10, PM2.5) , 20 L/min, PTFE 47φ
Monitor (Dust Track II)
PN MeasurementCPC 3750 (>7 nm) without pre-treatment
(APS (0.3–20 µm) without pre-treatment)
Soak Time: 10 min
in this study
Modification of Air Flow for PN (using Stage I) 7
Change Air Supply for Higher Air-Velocity and Lower Chamber Wall-Loss
0.0.E+00
1.0.E+09
2.0.E+09
3.0.E+09
4.0.E+09
5.0.E+09
6.0.E+09
0
5
10
15
1m³/min
4m³/min
1m³/min
4m³/min
NAO II pad LS pad
PMP cycle
PN
(C
PC
) [#
/km
/veh.]
PM
[m
g/k
m/v
eh.]
PM10
PM2.5
PN (CPC)
Flow Rate Effect for PN and PM Emission Factors (using Stage I)8
Emission factors for two different brake system tests under PMP cycle with
short soak time (10 min of soaking between trips) There was no significant difference between the total emission factors for
the two different flow rates (1 m3/min, 4 m3/min).
PMwheel=Ctunnel×Vtunnel×Ttest/Dmode
PMvehicle=PMwheel×Nfront+PMwheel×Nrear×(1-α)/αHere,PMwheel︓Emission Factor for a Wheel (mg/km/wheel), Ctunnel︓Concentration in Tunnel minus Tunnel Blank (mg/m3)Vtunnel︓Air Flow Rate of Tunnel (m3/min), Ttest︓Test Time (Measurement Time) (min)Dmode︓Driving Distance (1 mode) (km), PMvehicle︓ Emission Factor for a Vehicle (mg/km/vehicle)Nfront︓Number of Front Wheels, Nrear︓ Number of Rear Wheels, α︓Brake Torque Distribution (0.8 for this study)
For PN measurement,PNCtunnel︓PN Concentration in Tunnel minus Tunnel Blank (#/m3), PNwheel︓Emission Factor for a Wheel (#/km/wheel)PNvehicle︓ Emission Factor for a Vehicle (mg/km/vehicle)
4 m3/min(150A pipe)
1 m3/min(80A pipe)
Constant Volume and Isokinetic Sampling Emission Factors for PM and PN (without pre-treatment)
0
5
10
15
20
25
30
Total 1 2 3 4 5 6 7 8 9 10
PM
(D
ust Tra
ck II)
[m
g/k
m/v
eh.]
1m3/min 4m3/minLS, PM10
0
0.5
1
1.5
2
2.5
3
Total 1 2 3 4 5 6 7 8 9 10
PM
(D
ust
Tra
ck
II)
[mg/k
m/v
eh.]
1m3/min 4m3/minNAO II, PM10
0
2E+09
4E+09
6E+09
8E+09
1E+10
1.2E+10
1.4E+10
Total 1 2 3 4 5 6 7 8 9 10
PN
(C
OC
3750)
[#/k
m/v
eh.]
1m3/min 4m3/minLS, PN (CPC)
0.E+00
1.E+08
2.E+08
3.E+08
4.E+08
5.E+08
6.E+08
7.E+08
Total 1 2 3 4 5 6 7 8 9 10
PM
(C
PC
3750)
[#/k
m/v
eh.]
1m3/min 4m3/minNAO II, PN (CPC)
Flow Rate Effect for PN and PM Emission Factors (using Stage I)9
There was no significant difference between the total emission factors
under two different flow rates, but there may be differences of short trips emission factors. This must be analyze in further detail.
Comparison of Flow Condition (using Stage I) 10
Brake System: LS pad, Single Piston Caliper
Test Cycle: PMP (WLTC-Brake)
There was no significant difference between the total emission factors for
the different flow ratesParticle size distributions were unstable under different flow rates High Flow rate -> Measurement Near Brake Surface -> Nanoparticles may Increase ↗
Flow 1 m3/min 1 m3/min 4 m3/min
Res. Time ca. 5 s ca. 5 s ca.1.6 s
Slit without Silt with Slit with Slit
PM10 10.3±0.5 mg/km/veh. 11.8±1 mg/km/veh. 10.9±1 mg/km/veh.
PN (CPC) 4.1±0.5×109 #/km/veh. 4.1±0.7×109 #/km/veh 4.4±0.5×109 #/km/veh
PN Size (FMPS)
0.01 0.1 1
Mobility Particle Size [µm]
0.01 0.1 1
Mobility Particle Size [µm]
0.01 0.1 1
Mobility Particle Size [µm]
Comparison of Flow Condition (using Stage I) 11
Brake System: LS pad, Single Piston Caliper
Test Cycle: PMP (WLTC-Brake)
There was no significant difference between the total emission factors for
the different flow ratesParticle size distributions were unstable under different flow rates High Flow rate -> Measurement Near Brake Surface -> Nanoparticles may Increase ↗
0.0.E+00
1.0.E+09
2.0.E+09
3.0.E+09
4.0.E+09
5.0.E+09
0
2
4
6
8
10
1m³/min
1m³/min
1m³/min
1m³/min
1m³/min
1m³/min
RegenerativeBraking
NAO II NAO I LS NAO I LS
PMP cycle WLTC
PN
(C
PC
) [#
/km
/veh.]
PM
[m
g/k
m/v
eh.]
PM10 PM2.5 PN
PN and PM Emission Factors (using Stage I)12
Emission factors will differ for brake test cycles and brake systems.
A next generation brake technology (Simulated Regenerative Brake System) was demonstrated and very low emission levels were detected.
(Regenerative Brake: Control of input brake torque profile during PMP cycle)
0.0
0.2
0.4
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0.8
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1.4
1.6
1.8
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20
40
60
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180
NAO II NAO II
Regenerative Braking
PMP cycle
PM
10
[mg/k
m],
PN
(CP
C)
[#/k
m/5
x10
9]
Bra
ke T
orq
ue [
Nm
]
Ave. Brake Torque [Nm] PM10 [mg/km/veh.]
Torque68 % ↓PM10
67 % ↓
PN(CPC)40 % ↓
Comparison of Normal and Regenerative Braking(Different Torque Profile for PMP cycle)
Emission Factors for PM and PN (without pre-treatment)for Different Brake Systems and Cycles
Correlation of PN and PM Emission Factors (using Stage I)13
Good correlation with PN and PM was observed, but a different slope for
brake torque condition was also seen (possibly because of brake size distribution).
The brake system was uniform; only two different brake torques were used for normal and regenerative driving patterns.
y = 2.5E+08x - 3.7E+06R² = 9.9E-01
0.0.E+00
2.0.E+08
4.0.E+08
6.0.E+08
8.0.E+08
1.0.E+09
0 1 2 3 4
PN
(C
PC
3750)
[#/k
m/v
eh.]
PM10 (Dsut Track II)) [#/km/veh.]
Run1
Run2
Run3
NAO II (PM10) y = 4.5E+08x + 3.0E+06R² = 9.9E-01
0.0E+00
2.0E+08
4.0E+08
6.0E+08
8.0E+08
1.0E+09
0 1 2 3 4
PN
(C
PC
375
0)
[#/k
m/v
eh.]
PM10 (Dust Track II) [mg/km/veh.]
Run1
Run2
Run3
NAOII (Reg.) (PM10)
Flow Rate 35 m3/min
PM Emission Level for Regenerative Brake
below Detection Limit for PM
0
0.1
0.2
0.3
0.4
0.5
1 4 10 20 35 60
PM
[mg/k
m]
Flow Rate [m3/min]
PM10 PM2.5 Tunnel Blank
NAO II (Reg.) (PM)
0.0E+00
1.0E+09
2.0E+09
3.0E+09
4.0E+09
5.0E+09
6.0E+09
1 4 10 35 60
PN
(C
PC
)[#
/km
]
Flow Rate [m3/min]
Sample Tunnel Blank
LS PN (CPC)
0
5
10
15
20
1 4 10 20 35 60
PM
[mg/k
m]
Flow Rate [m3/min]
PM10 PM2.5 Tunnel Blank
LS (PM)
Detection Sensitivity for Stage II (PN and PM measurement)14
Because this study indicates that there were no significant total emission
factors with different flow rates, sensitivity analysis was demonstrated by using a typical tunnel blank concentration and
If we select a high flow rate for the cooling brake system, measurement becomes difficult owing to the contributions of the tunnel blank.
Typical Tunnel Blank (there are lower values using 10 years database in JARI)
PM: 10 µg/Filter,PN:10 #/cm3
Flow Rate 4 m3/min
PN Emission Level for Regenerative Brake
below Detection Limit for PN
Overview
Detection Sensitivity for PN and PM
Reproducibility of JARI Sampling System
Cycle Pattern Analysis for World Harmonization
Conclusions and Next Steps
Contents15
Reproducibility of JARI Sampling System (using Stage I)16
The JASO Standard for PM2.5 Measurement of Brake Systems will be
submitted to JASE by the end of July 2019.Reproducibility of the JARI sampling system was observed as 19% for 1
mg/km/veh. (±0.4 mg/km/veh.) of PM2.5 emission level during
interlaboratory testing.
Only PM2.5 survey in JARI / JSAE
Interlaboratory Testing with Same Brake Systems, Same Sampling Systems,Preexisting Dyno.
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
JARI A B C D
Laboratory
PM
2.5
[mg/k
m/v
eh.]
Average 1.01 mg/km/veh.
Wear Mass Difference ± 0.4 mg/km/veh.
Wear Mass Difference ± 0.4 mg/km/veh.
JASO: Japanese Automotive Standards OrganizationJSAE: Society of Automotive Engineers of Japan
[Testing Conditions]Pre-conditioning :
Initial Speed 65 km/h, Deceleration 3.5 m/s2, repeated 200 times
(or 1000 times for NAO discs), Vehicle:
Weight 1,130 kg, Ratio 8:2, Eff. Tire Rad. 0.298 m, Brake Systems:
NAO Disc (Front), Test Cycle:
NEDC (10 times with 10 min soaking), repeated 30 times (10 times/day)
Comparison of PM2.5 Emission Levels
Overview
Detection Sensitivity for PN and PM
Reproducibility of JARI Sampling System
Cycle Pattern Analysis for World Harmonization
Conclusions and Next Steps
Contents17
Cycle Pattern Analysis for World Harmonization 18
The PMP Brake Test Cycle was reviewed by Mr. Haniu from JARI, who is one
of the Experts of Establishment WLTC cycle at GRPE and Global Technical Regulations for Exhaust Test (This review is a Ministry of Environment (MoE) JAPAN Project).
MoE is considering distinguishing Asian Limit 3 Phase Cycles from EU Limit 4 Phases of PMP Brake Cycles based on World Harmonization
Processes.
Ex. Overview of the Cycle Development Process of WLTC
EU Limit 4 Phase to Asian Limit 3 Phase
Ex. Overview of the Brake cycle Development Process
EU Limit 4 Phase to Asian Limit 3 Phase
Ref. GRPE-68-03 (2014)
Review Results: Speed Distribution19
Speed distribution is exceeded by the Japanese legal speed (100 km/h)
(110 km/h for World Harmonization in WLTC establishment)
Review Results: Speed-Deceleration Distribution20
Speed-deceleration distribution
There were some differences between world driving patterns PMP cycles.Next Step: How much do the differences of the speed-deceleration
distribution contribute to PN and PM emission levels?
-2
0
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4
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-20 0 20 40 60 80 100 120 140 160
De
ce
lera
tio
n [km
/h/s
]
Speed [km/h]
Brake cycle all
-2
0
2
4
6
8
10
12
14
16
-20 0 20 40 60 80 100 120 140 160
De
ce
lera
tio
n [km
/h/s
]
Speed [km/h]
Worldwide Total
PMP Brake Cycle
WLTC Database
WLTC Cycle
WLTC Japanese Database
Review Results: Idling, Short Trip, Deceleration21
Idling: High frequency 3 s (45% of PMP cycle) (WLTC cycle is using widely)
Short Trip: PMP cycle 151 s, WLTC database 345 sDeceleration: Low frequency of low deceleration
0
10
20
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60
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90
100
0
1
2
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4
5
6
7
8
9
10
131
61
91
12
1
15
11
81
21
12
41
27
13
01
33
1
36
13
91
42
1
45
14
81
51
1
54
15
71
60
1
63
16
61
69
17
21
75
17
81
81
1
84
18
71
90
1
93
19
61
99
1
1021
1051
1081
1111
1141
1171
1201
Cum
. fre
quency
[%]
Fre
quency
[%]
Short trip duration [s]
Brake cycle
Brake cycle
Japan Total
Worldwide Total
0
10
20
30
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60
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80
90
100
0
5
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45
50
0 5
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160
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170
Cum
. fre
quency
[%
]
Fre
quency
[%
]
Idling duration [s]
Brake cycle
Brake cycle
Japan Total
Worldwide Total
0
20
40
60
80
100
0.1
4
0.4
2
0.6
9
0.9
7
1.2
5
1.5
3
1.8
1
2.0
8
2.3
6
2.6
4
2.9
2
3.1
9
3.4
7
Cu
m. F
req
ue
nc
y [
%]
Deceleration [m/s2]
Japan - Total Worldwide - Total WLTC - 4 phase Brake cycle
Idling Short Trip
3 s 45% of PMP cycle
WLTC cycle is using widely idling duration
Overview
Detection Sensitivity for PN and PM
Reproducibility of JARI Sampling System
Cycle Pattern Analysis for World Harmonization
Conclusions and Next Steps
Contents22
Conclusions:
• Good agreement is obtained between PN and PM emission levels under two different air flow rates (1 or 4 m3/min).
• A next generation brake technology (Simulated Regenerative Brake System) was demonstrated and very low emission levels were detected.
• High air flow rate (> 4 m3/min) was observed with low detection sensitivity due to typical tunnel blank levels
• Good correlation is obtained between PN and PM, but a different slope for brake torque condition is observed (possibly due to brake size
distribution) • Reproducibility of the JARI sampling system was observed as 19% for 1
mg/km/veh. (±0.4 mg/km/veh.) of PM2.5 emission level (Four Labs./NEDCcycle).
• Speed-Deceleration Distribution: There were some differences between world driving patterns PMP cycles.
Next Steps:
• Modification of air flow for PN measurement using uniform sampling
JARI/JASO model design.• Reproducibility of PN emissions
• How much do the differences of the speed-deceleration distribution contribute to PN and PM emission levels.
Conclusions & Next Steps 23