1. WLTP N/v tolerance Simulation results and conclusion BMW, 20.03.2015
Christoph Lueginger
WLTP N/v tolerance
Simulation results and conclusion

2. WLTP interpolation family n/v tolerance
JRC presentation Admin-WG 44a
WLTP interpolation family n/v tolerance, BMW, Lueginger,

3. WLTP interpolation family n/v tolerance
Case 1, most common n/v is shortest or longest
In the case, that the most common n/v is the shortest or longest, the maximum range is 8% and the tested ratio is the shortest.
The CO2-influence between the vehicles is very small and on the worst case side.
WLTP interpolation family n/v tolerance, BMW, Lueginger,

4. WLTP interpolation family n/v tolerance
Case 2, most common n/v is in the middle
In the case, that the most common n/v is in the middle, the maximum range is 16%, but the tested ratio remains the shortest one, as the GTR requires it this way.
The CO2-influence between the vehicles is small, the worst case is tested.
WLTP interpolation family n/v tolerance, BMW, Lueginger,

5. WLTP interpolation family n/v tolerance
Conclusion
As the GTR requires testing with the shortest ratio at type approval, there is no flexibility anyway.
For a typical case, where the range is not bigger than 8%, the CO2-influence is negligible.
There is no need and no basis to change the already agreed and UNECE adopted interpolation family criteria.
WLTP interpolation family n/v tolerance, BMW, Lueginger,

6. WLTP interpolation family n/v tolerance
Backup, text of interpolation family
5.6. Interpolation family
Unless vehicles are identical with respect to the following vehicle/powertrain/transmission characteristics, they shall not be considered to be part of the same CO2 vehicle family:
(a) Type of internal combustion engine: fuel type, combustion type, engine displacement, full-load characteristics, engine technology, and charging system, and also other engine subsystems or characteristics that have a non-negligible influence on CO2 under WLTP conditions;
(b) Operation strategy of all CO2-influencing components within the powertrain;
(c) Transmission type (e.g. manual, automatic, CVT) and transmission model (e.g. torque rating, number of gears, number of clutches, etc.);
(d) n/v ratios (engine rotational speed divided by vehicle speed). This requirement shall be considered fulfilled if, for all transmission ratios concerned, the difference with respect to the transmission ratios of the most commonly installed transmission type is within 8 per cent;
(e) Number of powered axles;
(f) [RESERVED: family criteria for EVs].
Annex 6, General
The test vehicle shall conform …
[…]
…and shall be tested with the shortest final transmission ratio within the interpolation family
WLTP interpolation family n/v tolerance, BMW, Lueginger,