Mr. Osaki first presented working paper HDH-09-11, which suggests a solution for the WHDHC other than the TU Graz approach. The proposal basically consists of applying a torque reduction factor to the WHTC. If the hybrid system does not work, i.e. no electric motor work is applied, the engine driving cycle would be the same as the WHTC. In cycle sections where the hybrid system is active, i.e. the electric motor works, the hybrid effect on the engine driving cycle can be reflected according to the respective hybrid system efficiency. The torque reduction rate would be calculated based on the WHVC on a flat road by obtaining the operating ratio of the engine to the total system in chronological order by HILS simulation (see page 9). Examples of the modified WHTC are shown on pages 11 to 14. Mr. Osaki pointed out that this approach is not applicable to serial hybrids.

He also made a proposal on how to consider cold start. A hybrid cold start algorithm could be realized in HILS by putting the water temperature profile of a cold start event of the vehicle or engine into the interface model and send them to the hybrid ECU in the cold start HILS simulated run.

The Japanese position is summarized on page 1 of working paper HDH-09-12. The extended HILS approach proposed by TU Vienna is not considered appropriate for certification because of the expected huge investment for the facilities and the complexity of the system.

The WHDHC approach proposed by TU Graz is considered reasonable, however, it does not use the vehicle basis and consequently does not properly reflect the difference between vehicle specifications. A comparison of the different approaches is shown on page 2.

In the discussion that followed Mr. Kawai indicated that the WHTC is generally not appropriate as basis for serial hybrids. It is common understanding of the group that the total powerpack system needs to be considered for emissions evaluation, not only the ICE. In general, a vehicle independent approach would be favorable, if it reflects the real world behavior of an HDV. The final method should also be suitable to give input needed by the various CO2 programs. Japan agreed that the WHTC could be the basis for criteria pollutants, but not for CO2.