Working paper No. WLTP-08-17-rev1e
Progress report Annex 4 Open Issues
Since the Geneva meeting in conjunction with IWG #7, Annex 4 open issues have been
discussed during two extra progress meeting, on 16 October 2014 in Delft, hosted by TNO
and on 12 November via web/audio conference organized by BMW.
1. Wind tunnel method (OI #10, #18)
The task assigned is to develop the wind tunnel with flat-belt method as an alternative to the
(WLTP) coast down method and to demonstrate equivalency. At IWG #8 BMW will present a
status report (WLTP-08-22e).
The French PFA test program, with the extension of flat-belt and additional wind tunnel
measurements at VW, is considered to cover all tests required for validation of the
wind tunnel with flat-belt method. The program is running on schedule and first preliminary
results are positive. Results will be presented at IWG #8 (UTAC, WLTP-08-23e)
VW is considering to perform additional tests to establish the vehicle warm up procedures for
flat-belt measurements. This is welcomed by the Task Force.
First ideas of requirements for the flat-belt method have been presented by VW and
discussed in the Task Force. VW will present an updated document for discussion at IWG #8
(VW, WLTP-08-24e)
The principles of the gtr text have been discussed and a first proposal will be available at
WLTP IWG #8 (BMW, WLTP-08-25e)
A final decision on OI #10 and #18 is foreseen for WLTP IWG #12, according to the OIL.
2. On-board anemometry and wind speed (OI #11, #13)
No progress on the on-board anemometry method program can be reported since IWG
#6. Progress is pending a proposal and a decision for the validation program.
At IWG #6 it was agreed that a validation program is required and should be run before
October 2014. This was confirmed at IWG #7.
Ford indicated in the Task Force that a new study is being run with US/EPA. Ford expects
the study plus an existing SAE-paper on On-board anemometer specifications to be
sufficient for validation and drafting under the gtr. This has to be assessed by the Task
Force.
The information is not yet made available to the Task Force.
OI #11 and #13 are not on schedule (proposal + adoption was foreseen for IWG #8). Only if
information from the US/EPA study becomes available and is considered to be sufficient
proof of equivalency, an alternative time schedule can be proposed.
3. Speed points (OI #12, #21)
The principles of reference speed definitions have been agreed in conjunction with IWG #7.
The last editorial issues have been solved since.
The total package (WLTP-08-28e) is now under scrutiny of Task Force members of different
Contracting Parties. A final adoption is expected at IWG #8.
It was recognized that additional speed point issues might emerge related to the
development of the torque meter method (OI #14, 15, 16, 20) and the Road load family
concept (OI #1b_2). Proposals will be dealt with under these OI’s.
If WLTP-08-28e is adopted, the Task Force considers OI #12 and #21 closed.
4. Torque meter method (OI #14, #15, #16, #20)
In the Delft meeting of the Task Force Ford presented details of the set-up of torque meter
measurements and the results of a first test run. Ford aims to perform two additional tests in
the short term. A new document with a description of the torque meter method, including
specifications and calibration requirements, is under preparation. Certification schemes for
torque meters are in place and will be included in the proposed requirements.
The Task Force welcomed the offer of Ford to provide additional measurements. The results
will be assessed in the Task Force in short term. Taking into account the existing certification
schemes for torque meters, there are no indications that additional validation on top of the
full Ford test program is required. The torque meter approach as applied by Ford is simple
by nature.
The approach for chassis dyno setting was discussed; this requires extra provisions in the
gtr.
First proposals on modifying the method to deliver three road load parameters (OI #16) have
been circulated.
A proposal to modify the general reference speed points provisions will be drafted.
OI #14, #15 are behind schedule. A presentation by Ford of test results and initial gtr
proposals (covering OI #14, #15, #16, #20) is foreseen for IWG #9 in Geneva.
5. Default road load parameters (OI #17)
A review of the default road load table values, strongly requested by OICA members, is
pending the availability of new data. Only one example was send to the Task Force since
WLTP IWG#7.
As announced at IWG #7 RDW presented details of the hybrid approach and the first
principles of how to incorporate the hybrid approach in the gtr. Initially the hybrid approach
was aiming at multistage vehicles only. In the Task Force it was suggested that by extension
of the scope of the hybrid approach the objections against the table values might be partly
solved. OICA members will check their support for an extension of the scope of the hybrid
approach. Drafting is pending the outcome of this survey.
The Hybrid approach and the extension of the scope will be presented for discussion at IWG
#8 (RDW, WLTP-08-26e). Reflections of the car industry will be distributed in advance
(WLTP-08-27e).
If IWG #8 welcomes the Hybrid approach, a decision to proceed with the Hybrid approach
can be presented at IWG #9.
6. Warm up procedure (OI #19)
An initial proposal from Japan containing the general principles of an alternative warm-up
procedure was discussed in the Task Force. Based on these discussions an updated
proposal, supported by the Task Force, is made available (WLTP-08-29e) for adoption in
IWG #8.
If the general principles are adopted, a draft gtr text will be made available for adoption at
IWG #9.
7. Road load family concept (OI #1b_2)
At WLTP-IWG #6 it was agreed to develop the RL family concept. The Task Force agreed
on the roadmap presented by BMW and in conjunction with WLTP-IWG #7 the Task Force
agreed with the initiative of BMW to set up a validation test program. The first measurements
have recently started. Progress report and initial draft proposals are available for discussion
at IWG #8 (BMW, WLTP-08-19e, WLTP-08-20e).
OI #1b_2 is on schedule for final adoption in IWG #10.
8. Tyre rolling resistance under combined approach
If IWG #8 decides, on the request of the European Commission, to adopt a new issue on
handling the tyre rolling resistance under the combined approach (WLTP-08-18e), this will
be added to the Annex 4 agenda.