1. J. Pavlovic, A. Marotta, B. Ciuffo WLTP 2nd Act June 14th, 2017
Update on correction of test cycle flexibilities
J. Pavlovic, A. Marotta, B. Ciuffo WLTP 2nd Act June 14th, 2017

2. Background
JRC applied speed + distance CO2 corrections proposed by TUG on a number of vehicles tested in JRC, some OEMs and TSs labs;
In most cases repeatability and reproducibility of results increased after corrections;
In most cases deviations from the target power and distance were very small and corrections only slightly effected the final CO2 result;
Last time we presented results of corrections applied to VW and JARI tests that applied normal, rough and smooth driving WLTP conditions. In addition, DIs for these tests were calculated.

3. Background
Corrections applied to VW rough and smooth tests significantly improved results and lowered standard deviation from 6.4 g/km to 1.2 g/km.

4. Background
Test results from 9 JARI vehicles were processed and in most cases correction of CO2 results from smooth and rough driving had only small impact on final result and did not result in full alignment with results of “normal” driving test (especially for cases of rough driving);
In most cases DIs detected the extreme (smooth and rough) tests;
Possible approach would be to use DIs to eliminate extreme tests and correction to apply only on tests where DIs were within the agreed threshold limits;
Japan proposal from the last WLTP IWG meeting (18th) is to set criteria for these DIs as following:
RMSSE (Root Mean Squared Speed Error) < +0.8
IWR (Inertial Work Rated) -2.0 ~ +4.0

5. Work in progress RMSSE and IWR were calculated from 58 WLTP tests;
No linear correlation between RMSSE and %CO2 was found;
RMSSE limit of 0.8 will classify 39 tests as invalid

6. Work in progress
Some linear correlation between IWR and %CO2 can be seen
IWR limit of -2% to +4% will classify 22 tests as invalid and limit of -4% to +4% 21 tests as invalid

7. Work in progress
All tests that had IWR outside of threshold limits had RMSSE >0.8 km/h
Not valid tests
Valid tests
Valid tests
Not valid tests

8. Conclusions Two step approach is suggested:
Calculation of DIs (IWR and RMSSE) to eliminate extreme tests; and
Correction to apply only on tests where DIs were within the agreed threshold limits;
RMSSE of 0.8 km/h and IWR range of -4 (-2%)% to +4% is proposed;
In addition, safety margin for corrections can be proposed, e.g. with correction criteria (like for RCB correction).