Dr. Perujo presented working paper HDH-15-09 as a short introduction of the validation test program 2 (VTP2). The goal of VTP2 is to provide a methodology for verifying the HILS model in the gtr and to elaborate a new verification procedure for the gtr, if necessary. The measurement procedure is explained on pages 4 to 6. The three vehicles were tested at JRC between May and September 2013 with the Volvo bus being tested twice. As regards the accuracy of the chassis dyno, torque measurement was within ± 10 % of a wheel hub torque meter. Higher deviations were observed on the WHVC compared to constant vehicle speed operation. Data processing and comparison between experimentally measured parameters and parameters obtained by the HILS model is underway. Further investigations are necessary for resolving some of the problems encountered during the test program.

Mr. Six presented a detailed analysis of the HDH drive cycle (WHVC with road gradients) on pages 11 to 33 of HDH-15-04. Parts of the investigations were done in conjunction with the chassis dyno tests at JRC. He concluded that the minicycle approach very well aligns WHVC and WHTC. This is considered a solid basis for the new test cycle. The approach considers added and removed payloads for positive and negative work, thereby matching of positive WHTC work independent of test weight (i.e. slopes will adjust work). A great benefit is that negative work is independent of test weight, so that adequate recuperation energy is always available. This better reflects real world operation for different payloads. A summary of the methods analyzed (minicycle, 30 sec average, individual slope, fixed slope) is shown on page 32. The final test cycle proposal of the institutes is a minicycle approach with positive and negative WHTC work, which is a clear improvement over the flat WHVC approach.

The detailed test results are shown on pages 36 to 48 for the Volvo bus and on pages 50 to 59 for the MAN bus. An analysis of the Iveco results is not available, since HILS modelling is still under construction. Additional chassis dyno tests are planned for early 2014.

As a conclusion, the Japanese verification (R² criteria) failed until now. Identification of the causes is ongoing, with respect to the HILS model, the chassis dyno measurements and a combination of both. Regression analysis is principally considered as a good basis, but further investigation regarding time sensitivity and alternatives is needed. Mr. Six concluded that it is premature to agree on HILS certification procedure on a solid technical basis.