1. Additional RDE trip indicator(s)
European Commission - Joint Research Centre (JRC)
IET - Institute for Energy and Transport

2. Background for the work
The RDE procedure contains methods to assess the dynamic conditions over a PEMS trip (ex-post evaluation)
“Composite” indicators (of vehicle speed-accelerations, road grade, wind) are used to assess the severity of driving conditions (average window CO2 mass for EMROAD, instantaneous power at the wheels for CLEAR)

3. Background for the work
Current assessment of dynamic conditions: CO2 or power as indicators
Engine-Out (NOx) Emissions
Insufficient
Normal
Excessive
Driving severity/dynamicity

4. Background for the work
Risk : wrong assessment of testing conditions in these two regions
using the current data evaluation methods
Engine-Out (NOx) Emissions
Insufficient
Normal
Excessive
Driving severity/dynamicity

5. Background for the work
Tests could be validated using complementary indicators
Engine-Out (NOx) Emissions
Insufficient
Normal
Excessive
MAX CF
Tailpipe (NOx) Emissions
Driving severity/dynamicity
Severity indicators = Mainstream & Complementary
Engine-Out (NOx) Emissions

6. Contents Four stage approach towards complementary trip indicators
Identifying the problem; if concerns are valid:
Proposing suitable indicators
Agreeing on thresholds
Agreeing on implementation

7. Identifying the problem
Two parts:
Shared data as part of the RDE data evaluation task force (V001, V005 in the RDE DE task force database)
New data obtained from ACEA in the past month (V006, V008 from ACEA round robin test)

8. Trip driven aggressively invalidated by MAW method
Previous data
V001_Route#1 driven with standard and aggressive driving styles:
Power/Mass=74; EMROAD v5.8
↓ windows within 25% of the CO2 reference from standard to aggressive
Trip driven aggressively invalidated by MAW method

9. Trip driven aggressively invalidated by MAW method
Previous data
V005_Route#1 driven with soft, standard and aggressive driving styles:
Power/Mass=91.8; EMROAD v5.8
↓ windows within 25% of the CO2 reference from soft to standard and aggressive
Trip driven aggressively invalidated by MAW method

10. New ACEA (Round Robin) Data
Trip data provided by ACEA: time, instantaneous CO2 emission, exhaust mass flow rate, vehicle speed, GPS data, coolant temperature, engine torque, ambient temperature and pressure
Neckarsulm
Steyr
Wolfsburg
Stuttgart
Soft
Standard
Aggres.
V006 OK
V007
V008
3 pairs of standard/soft vs. aggressive driving on the same route and vehicle
NOx data available for 2 tests (Total results only)

11. Trip driven aggressively validated by MAW method
New Data
V006 WOB route - Soft and aggressive driving styles:
EMROAD v5.8 – Power/Mass=?
almost all windows within 25% of the CO2 reference from soft to aggressive
Trip driven aggressively validated by MAW method

12. Trip driven aggressively validated by MAW method
New Data
V008 WOB route - Standard and aggressive driving styles:
EMROAD v5.8 – Power/Mass=?
almost all windows within 25% of the CO2 reference for both tests
Trip driven aggressively validated by MAW method

13. Trip driven aggressively invalidated by MAW method
New Data
V008_NSU driven with soft and aggressive driving styles:
EMROAD v5.8 – Power/Mass=?
↓ windows within 25% of the CO2 reference from soft to aggressive
Trip driven aggressively invalidated by MAW method

14. Preliminary conclusion
Cumulative CO2 mass does not invalidate aggressive tests for some vehicle-engine-route combinations provided by ACEA
Window average CO2 emissions may not always be sufficiently sensitive to detect severe instantaneous driving events
Why is this the case for some vehicles-routes combinations and not for others?
Compensation of wind and road grade effects?
Vehicle-engine characteristics?
Subjective driver judgement?
The need for an additional indicator seems legitimate:
Observations for a limited number of diesel vehicles
Severity of the trips claimed to be aggressive must be agreed with respect to a reference, based on a number of agreed indicators

15. JRC general comments
Studies shall be conducted for individual and valid vehicle-route combinations
The analysis should detail the results for urban, rural and motorway driving
The percentage of normal windows is not an indicator for the severity of the driving

16. Additional indicators
Analysis of additional indicators
EMROAD: window average CO2 emissions
ACEA proposal – 95-percentil of v*a_pos
Differences: indicator, statistical parameter, data sample

17. Investigation of instantaneous CO2 based indicator
Indicators
V006_WOB driven with soft and aggressive driving styles:
All data points included:
Aggressive
Soft
Similar average CO2 emissions (g/s), over the total trip, for soft and aggressive
Increased scatter of CO2 emissions, over the total trip , for aggressive trip
Investigation of instantaneous CO2 based indicator

18. Indicators CO2 emissions and 𝑣∗ 𝑎 𝑝𝑜𝑠,95𝑡ℎ correlation:
All data points included
Urban
Rural
Motorway

19. Indicators V006_WOB driven with soft and aggressive driving styles:
Only positive acceleration: Data considered for 𝑣∗ 𝑎 𝑝𝑜𝑠,95𝑡ℎ calculation:
Aggressive
Soft
CO2 emissions and test conditions:
Increased average CO2 emissions, over the total trip, for aggressive trip
Increased 95th percentile CO2 emissions, over the total trip , for aggressive trip

20. Indicators CO2 emissions and 𝑣∗ 𝑎 𝑝𝑜𝑠,95𝑡ℎ correlation:
Only positive acceleration
Urban
Rural
Motorway

21. MAW Severity Indices Severity indices vs. driving style:
Urban
Rural
Motorway
Severity index: distance of window average CO2 emissions from the reference curve
Increase of severity index passing from soft to standard and aggressive driving style

22. Indicators
V004 (RDE DE TF Database)
RPA

23. Conclusions and next steps
Need to complement data evaluation with additional indicators partially established
Additional trip indicators could make the data evaluation more robust
Objectives for the RDE DE Task Force
- To improve the robustness of the procedure
- Complementing the data evaluation methods with trip indicators
- Complementing the RDE procedure with ex-ante trip
requirements (road grade)
Discussion on indicator values: which reference? (EU WLTP data pool complemented by soft-extreme PEMS data)
Implementation of indictors: data point exclusion/window invalidation/trip invalidation

24. Indicators CO2 emissions and 𝑣∗ 𝑎 𝑝𝑜𝑠,95𝑡ℎ correlation:
Only positive acceleration
Aggressive
Soft/Standard

25. Indicators CO2 emissions and 𝑣∗ 𝑎 𝑝𝑜𝑠,95𝑡ℎ correlation:
All data points included
Aggressive
Soft/Standard

26. V006-WOB

27. V008-WOB

28. V008-NSU

29. 9 tests shared, preliminary analysis with MAW method(*):
(*) snapshot from ACEA presentation “2015_Necessity-dyn-boundaries-final-ACEA_PR_0208_BR”
EMROAD – trip validity:
U/R/M windows based on average speed (≤45 km/45-80 km/h/>80 km/h)
At least 15% of windows in each U/R/M phase
At least 50% of windows within 25% of the CO2 reference in each U/R/M phase

30. Selected data - Overview
EMROAD – trip validity:
U/R/M windows based on average speed (<45 km/45-80 km/h/>80 km/h)
At least 15% of windows in each U/R/M phase
At least 50% of windows within 25% of the CO2 reference in each U/R/M phase
Every trip has a specific overall minimum percentage of windows that have to be within the 25% of the CO2 reference to be valid!
MAWs share [%]
MAWs ±25% tolerance [%]
𝑁𝑜𝑟𝑚𝑎𝑙 𝑤 %
Urban
Rural
Motorway
Case #a: Balanced trip / best case 34 33 50
100 83
Case #b1: Unbalanced trip / best case 15 70
92.5
Case #c1: Unbalanced trip / best case 60
Case #d1: Unbalanced trip / best case 26 44 30 87
Case #d2: Unbalanced trip / best case 78
Case #d3: Unbalanced trip / best case 85
Cases #a,b,c,d: worst case

31. Background for the work
The data evaluation methods assess the combined effects of vehicle dynamics, road grade, wind
Engine-Out (NOx) Emissions
Insufficient
Normal
Excessive
Driving severity/dynamicity