GAR | WLTP-DTP-10-02

1	2	4
Document Title	Combined solution for vehicle test mass definition, inertia mass step-less approach, vehicle and tire selection
Reference Number	WLTP-DTP-10-02
Date	1 Jun 2012
Summary	In 2011, the WLTP-DTP group agreed to pursue an improved definition of vehicle test mass and a step-less approach to the inertia class system. This revised document describes the current view on the combined approach for vehicle test mass, inertia setting, tire and vehicle selection.
Source(s)	ICCT, T&E, RDW, and Netherlands
Rulemaking Area(s)	GTR No. 15 WLTP
Meeting(s)	WLTP-DTP \| Session 10 \| 6 Jun 2012
Downloads
UNECE server	.pdf format
Excerpts from session reports related to this document
WLTP-DTP \| Session 10 \| 6 Jun 2012		A report has been given by Stephan Redmann (doc. WLTP‐DTP‐10‐09). During several meetings, much progress on open issues and a contribution to drafting has been made. All open issues of LabProcICE are now incorporated in the GTR draft document. Further on a complete evaluation list has been provided to VTF. ► Test mass/inertia classes/vehicle selection: The Tyre Selection Criteria is now excluded from this approach. The proposal from DTP9 to use a tyre from the worst tyre rolling resistance class is accepted by DTP10. However, the final decision, if the selection criteria should be class‐based only, shall be based on an ICCT study on the CO2 influence of tyre rolling resistance. The basis for this evaluation study shall be the WLTC. Results are expected at the beginning of July. Japan presented a proposal to exclude the aerodynamic options from the combined approach and to use the worst aerodynamic case instead (see presentation by Japan). The main justification therefore is seen in the important contribution of aerodynamic parts to CO2 emissions of future vehicles. The DTP Group discussed whether to head towards a more representative vehicle testing (LabProcICEProposal) or to head towards worst case testing (Japanese Proposal). The DTP Group tends to stick to the combined approach including aerodynamic options as was proposed at DTP9. LabProcICE strongly asks the Group for opinions in order to come to a clear position. To provide more clarity on this issue Japan agrees to do a separate evaluation of the aerodynamic parts during VP3. ► Payload Factor The current payload proposal (+15% for M1 and +35% for N1) is confirmed by LabProcICE. Additional proposals (as from India and Japan) shall be justified on the basis of field data. A final decision is foreseen to be reached after VP2. ► Family Concept The OICA proposal is approved by DTP10. OICA is asked by DTP to further work out this approved family concept. OICA promises to present a revised version at DTP11. ► Table of Running Resistances No decision could be made by DTP due to reservations on the current proposal by the European Commission and the lack of any counter‐proposal. ► Fan Speed DTP9 agreed in principle to introduce a proportional fan speed up to maximum cycle speed. It turned out that several test laboratories have difficulties to realise fan speeds over 120km/h. Due to cost/benefit reasons (high investment but possibly low impact on measurement result) OICA proposed to allow a speed deviation of up to 15% in order to be able to use existing laboratory technology. NL, F, D, PL, J express concerns regarding this proposal. Although some contracting parties expressed sympathy for the difficulties implementing fan speeds higher than 120km/h. A possible compromise solution could be to introduce a maximum tolerance level of 8% (according to US regulation). This issue will further be investigated at LabProcICE.