1. WLTP-DTP-LabProcICE-189
Introduction of SAE J2951 study - possibility of tighter tolerance for WLTP phase -
It is not ‘normalization’.
But we would like to introduce it as one of the solution of less flexibility.

2. SAE J2951 Index Engine force
FENG = [F0 + F1*V + F2*V * ETW * a]+
Engine work increment
Wi = FENGi * di
Cycle energy (CE)
CE = ΣWi = Σ[(F0 + F1*Vi + F2*Vi * ETW * ai) * di]+
Energy rating (ER)
ER = (CED - CET) / CET*100
Distance rating (DR)
DR = (DD - DT) / DT*100
Energy economy rating (EER)
EER = [1 – (DR / ) / (ER / )] * 100
Absolute speed change rating (ASCR)
ASCR = (ASCD - ASCT) / ASCT * 100
ASC = ⊿t*Σ|ai|
Root mean squared speed error (RMSSE)
RMSSE = * √(Σ(VDi - VTi)2) / N)

3. Points of evaluation J2951 Index can; Evaluated data，
Detect too smooth driving within tolerance?
Detect it is due to vehicle performance or other intention?
Evaluated data，
Data unable to follow the target due to vehicle performance.
Exclude the data with wide open throttle from above.
Data able to follow the target.
Index RMSSE may be effective?
Need more data for practicability to achieve tighter tolerance.

4. Analysis of SAE J2951 Index by Validation data
Points of view
Detect the data unable to follow the target trace?
If exclude the data with WOT, the index become normal. (=similar as the data able to follow the target.)
Unable to follow
Unable to follow (Ex. WOT)
Able to follow (MT)
Able to follow (AT)
Detected !
DR also detected well, but distance can be adjusted easily.
RMSSE works well. But analyzed by only 4 data…
(Much) more data is necessary to evaluate practicability.

5. How to exclude the data with WOT?
Black : Speed
Red : Throttle Pedal angle
These data are excluded from INDEX calculation.
WOT
Signal of throttle pedal angle or WOT is necessary.

6. Sensitivity of RMSSE (Ex-H)
Exceeding tolerance
Integration of (Vtarget -Vactual)2
If the data exceeding the tolerance is excluded, RMSSE≒0.596
RMSSE responds sensitively although the speed gap is within tolerance and short time period. It may be good INDEX for tighter tolerance.
But more data analysis is necessary.