2. BRAKE PARTICLE EMISSIONS
TASK FORCE 1
Development of a NEW REAL-WORLD BRAKING CYCLE FOR STUDYING BRAKE PARTICLE EMISSIONS
Theodoros Grigoratos, Marcel Mathissen, Christian Schmidt,
Jarek Grochowicz, Rainer Vogt, Heinz Steven and TF1 Members
47th PMP IWG Meeting – Ispra (IT) –

3. NON-EXHAUST PARTICLE EMISSIONS
Development of a NEW REAL-WORLD BRAKING CYCLE FOR STUDYING BRAKE PARTICLE EMISSIONS
WLTP Database Analysis (Concluded)
Comparison of WLTP data with Existing Industrial Cycles (Concluded)
Development of a first version of the new (WLTP based) and backup (LACT based) braking schedule (Concluded)
Validation of the cycles - Round robin (reproducibility assessment on different dynos) (Deadline: March – April 2018) (Deadline: December 2018)

4. NON-EXHAUST PARTICLE EMISSIONS
Development of a NEW REAL-WORLD BRAKING CYCLE FOR STUDYING BRAKE PARTICLE EMISSIONS
FORD has concluded the development of the schedule in collaboration with Heinz Steven
Technical details regarding the cycle will be presented in EuroBrake 2018
The cycle will become available to the public after its acceptance to the WEAR Journal (June 2018)

5. NON-EXHAUST PARTICLE EMISSIONS
Development of a NEW REAL-WORLD BRAKING CYCLE FOR STUDYING BRAKE PARTICLE EMISSIONS
i. What was the motivation for the development of the new cycle?
Brake emission testing shall be done under representative driving conditions
Currently available driving cycles used in the brake testing (e.g. Mojacar, LACT) were developed for other purposes and they need max brake temperature above 200ºC
Mojacar average / max temperature: ºC / >250ºC
LACT average / max temperature: ºC / >200ºC
Reaching above temperatures require adequate driving pattern and vehicle payload
As result, these procedures generate more wear and higher PN emissions compared to reality
Need for a new standard cycle representing normal driving style and average payload

6. NON-EXHAUST PARTICLE EMISSIONS
Development of a NEW REAL-WORLD BRAKING CYCLE FOR STUDYING BRAKE PARTICLE EMISSIONS
ii. What was the procedure followed for the development of the new cycle?
The WLTP database was used as a basis for the new braking schedule
The database includes in-use driving data
Five regions (EU, USA, India, Korea and Japan)
Total mileage: km
1 Hz data of vehicle speed, engine speed (for most vehicles), date and time of the day and trip number
Should be company independent and by this find (world)wide acceptance

7. GENERATION OF THE CYCLE
Development of a NEW REAL-WORLD BRAKING CYCLE FOR STUDYING BRAKE PARTICLE EMISSIONS
GENERATION OF THE CYCLE
Statistical distributions included in the development of the novel brake cycle*:
Brake phase duration
Brake phase distance
Number of brake phases per km
Data is complemented by an additional analysis of the WLTP in-use database for this study:
Initial velocity
Average deceleration
Duration between brake phases

8. NON-EXHAUST PARTICLE EMISSIONS
Development of a NEW REAL-WORLD BRAKING CYCLE FOR STUDYING BRAKE PARTICLE EMISSIONS
iii. What were the main steps for the generation of the new cycle?
Step 1: Analysis of statistical distributions
Step 2: Candidate short trips from the WLTP were selected and put together to a first cycle
Step 3: In order to match time between stops: stop phases or constant speed phases are inserted
Step 4: Fine-tuning (replacement of segments, rectification: linear/decrease increase of decelerations/accelerations, etc.)
Step 5: Division of cycle into 10 trips with 9 breaks (varying between sec based on the WLTP data) to match average trip length of the WLTP

9. Development of a NEW REAL-WORLD BRAKING CYCLE FOR STUDYING BRAKE PARTICLE EMISSIONS
NOVEL CYCLE
303 stops at a distance of 192 km
4h 24min duration
Average speed of 44 km/h and maximum speed of 133 km/h
Deceleration 0.49 – m/s² (mean of m/s²)

10. COMPARISON WITH LACT & WLTP STATISTICS
Development of a NEW REAL-WORLD BRAKING CYCLE FOR STUDYING BRAKE PARTICLE EMISSIONS
COMPARISON WITH LACT & WLTP STATISTICS
The novel cycle closely matches the statistical distributions of the WLTP database not only for initial velocity, deceleration and brake duration but for all selected parameters

11. DEVELOPMENT OF THE CYCLE
Development of a NEW REAL-WORLD BRAKING CYCLE FOR STUDYING BRAKE PARTICLE EMISSIONS
DEVELOPMENT OF THE CYCLE
Cycle reproduction at a vehicle level (Delayed – Concluded)
Cycle reproduction on the brake dyno (Delayed – Concluded)
Effect of cooling air velocity
Effect of dyno inertia (vehicle mass)
Effect of parasitic drag
Correlation between the brake dyno and the vehicle (Concluded)

12. CYCLE REPRODUCTION AT A VEHICLE LEVEL
Development of a NEW REAL-WORLD BRAKING CYCLE FOR STUDYING BRAKE PARTICLE EMISSIONS
CYCLE REPRODUCTION AT A VEHICLE LEVEL
Middle class vehicle (15” brakes: Sliding callipers, Grey Iron Discs and LowMet Pads)
Additional pedal box, cycle monitor (trace of actual and target speed) to the co-driver

13. CYCLE REPRODUCTION AT A VEHICLE LEVEL
Development of a NEW REAL-WORLD BRAKING CYCLE FOR STUDYING BRAKE PARTICLE EMISSIONS
CYCLE REPRODUCTION AT A VEHICLE LEVEL
Ambient temp of 8ºC – 18ºC and mean temp of 11ºC
Disc temp during testing was ~50ºC (mean) and 128ºC max

14. CYCLE REPRODUCTION AT A BRAKE DYNO LEVEL
Development of a NEW REAL-WORLD BRAKING CYCLE FOR STUDYING BRAKE PARTICLE EMISSIONS
CYCLE REPRODUCTION AT A BRAKE DYNO LEVEL
Identical brake parts as during vehicle testing
Two set-ups were tested in the dyno
Standard brake test setup with a horizontal cooling of 2200 m³/h
Brake emission measurements setup with a cooling rate of 250 m³/h (enclosed measurement set-up)
Tested the influence of the following parameters
Parasitic drag (gear, rolling, aero)
Vehicle mass (dyno inertia)
Cooling air speed / temperature / humidity

15. Development of a NEW REAL-WORLD BRAKING CYCLE FOR STUDYING BRAKE PARTICLE EMISSIONS
EFFECT OF COOLING RATE
For the standard set-up (horizontal cooling of 2200 m³/h) dynamometer temperatures were found to be slightly lower compared to those recorded on vehicle

16. Horizontal cooling (2209 m³/h)
Development of a NEW REAL-WORLD BRAKING CYCLE FOR STUDYING BRAKE PARTICLE EMISSIONS
EFFECT OF COOLING RATE
Cooling Condition
Tmean [°C]
TMax [°C]
Horizontal cooling (2209 m³/h) 49
120
Enclosed measurement
set-up (250 m³/h) 70
170
No cooling 86
197
VEHICLE 50
129
Temperatures under high flow conditions compare better with temperatures in the field
Temperatures under low flow conditions are higher than in the field
Risk of PN emissions overestimation

17. EFFECT OF PARASITIC DRAG
Development of a NEW REAL-WORLD BRAKING CYCLE FOR STUDYING BRAKE PARTICLE EMISSIONS
EFFECT OF PARASITIC DRAG
Parasitic drag includes aerodynamic drag, rolling resistances, brake drag, etc.
On average, 15% of the kinetic energy of a stop in the novel brake cycle is being dissipated by parasitic drag

18. EFFECT OF PARASITIC DRAG
Development of a NEW REAL-WORLD BRAKING CYCLE FOR STUDYING BRAKE PARTICLE EMISSIONS
EFFECT OF PARASITIC DRAG
Low influence on average temperatures (52ºC vs. 49ºC) but higher on max temperatures (135ºC vs. 120ºC)

19. BRAKING TEST CYCLE – CURRENT STATUS
FORD has developed the WLTP based profile in collaboration with Heinz Steven. The profile has being validated by FORD both on-road and on the dyno
The novel cycle closely matches the WLTP database to simulate real-world driving conditions
The selected profile will be used for bedding in of the pads. There is a practical issue as the proposed cycle is quite long

20. BRAKING TEST CYCLE – OPEN ISSUES
Low flow dynamometer testing will lead to higher maximum temperatures than observed in the field. How can we reproduce correct temperature levels?
Which temperature will be achieved for other vehicles (vehicle classes)
How to adapt cycle to other vehicle classes?
Influence of breaks between the trips
Temperature level and cooling influence on other test setups for emission testing

21. BRAKING TEST CYCLE – NEXT STEP
A round robin has been scheduled for the next months with the purpose of validating both braking schedules in terms of temperature. All labs participating in TF1 will take part and the round robin is expected to be completed by the end of
A paper with the title “A novel real-world braking cycle for studying brake wear particle emissions” has been submitted to WEAR and is expected to be published soon

22. Any questions?
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