Presentation on theme: "Working Paper No. WLTP-09-07e 1 Agenda item 5: Progress report on Downscaling / Gearshifting (OIL #4-9) by H. Steven 06.01.2015 9 th WLTP IG meeting, 14."— Presentation transcript:
Working Paper No. WLTP-09-07e 1 Agenda item 5: Progress report on Downscaling / Gearshifting (OIL #4-9) by H. Steven th WLTP IG meeting, 14. January 2015
Downscaling 2 The downscaling procedure is specified in GTR 15 in paragraph 7 of annex 1. The method as such is agreed, but paragraph 7.3 “Determination of the downscaling factor” needed to be amended. India requested modifications of the calculation parameter/coefficients r 0, a 1 and b 1 and made already a proposal for amendments (see WLTP-DHC-18-05). This issue is related to OIL # 5. Meanwhile additional analysis work was performed by the task force and an amendment proposal was presented to the IG at meeting #8 (see WLTP-08-10e).
Downscaling 3 This proposal was adopted at WLTP IG #8, so that the work is finalised and OIL #5 can be closed.
Downscaling, using torque meter method results 4 Another point on the issues list is related to the use of road load coefficients in the downscaling factor calculation formulas. OIL # 4 (Calculation parameter/coefficients for torque meter method): The problem was clarified between Japan and HS (coast down method delivers f0, f1 and f2, torque meter method delivers C0, C1 and C2). This issue should be dealt with in the annex 4 task force in conjunction with OIL #16.
Gearshifting, issues list 5 The gearshift prescriptions for manual transmission vehicles are specified in annex 2 of the GTR. The actual issue list contains the following points: 1.OIL #6, annex 2, section 2, Use of the gearbox, required data, 2.OIL #6, annex 2, section 2, Use of the gearbox, auxiliary gearboxes, exception of crawler gears, 3.OIL #6, annex 2, sections 3.2 and 3.3, Determination of engine speeds, calculation of available power
Use of gearbox, required data 6 OIL #6-1, use of the gearbox, required data can be split into the following subsections: 1.the definition of n min_drive should be modified in order to make it more appropriate for modern engines and to make manipulations more difficult. 2.n max needs to be added to section 2, required data and needs to be amended, because the current definition is not appropriate for low powered vehicles. 3.section 2 (i), P normwot (n norm i, j ) should be replaced by P wot (n i, j ), since there is no need for the normalisation.
Definition of n min_drive 7 The issue of an amendment of n min_drive is by far the most complex and controversely discussed issue. The current discussion is based on 3 different proposals, but since the 3 rd proposal was delivered rather late to the task force (shortly before WLTP IG #8), so that the task force of course needs some time to assess the proposals. Therefore the GS-TF asked the WLTP IG at meeting #8 for an extension of the time schedule for this issue in order to allow more detailed discussions and assessments. The task force should work on an amendment proposal to be ready for adoption at WLTP IG #10.
Definition of n max 8 The current definition in the GTR is n max = 1,2*(n rated – n idle ). India requested to come back to the previous definition n max = 0,9*(n rated – n idle )+n idle, if ng < ng vmax. A new proposal for n max was introduced by the chairman: If ng < ng vmax. n max is the minimum engine speed, where 95% of rated power is reached, else n max is limited by v max of the WLTC. ng vmax is the gear number, in which the maximum vehicle speed is reached. This proposal was adopted by the task force and presented to the WLTP IG at meeting #8. The proposal was adopted by the IG.
P normwot (n norm i, j ) -> P wot (n i, j ) 9 During the development process of the gearshift prescriptions normalised full load power curves versus normalised engine speeds had to be used in order to assess the results for different engine and powertrain combinations. For a particular vehicle under test the use of normalised curves is an unnecessary burden, because the current prescriptions in annex 2 require a denormalisation. Therefore the task force proposed to amend the text in annex 2 accordingly. This proposal was presented at WLTP IG #8 and adopted.
Auxiliary gearboxes, exception of crawler gears 10 OIL #6-2, use of the gearbox, required data can be split into the following subsections: 1.Add requirements, how to deal with vehicles with a two range transmission (low and high), 2.Introduce the possibility to exclude crawler gears from the gear use calculation. With respect to 1. the task force proposed to add a new subsection 1.4 to section 1 of annex 1 with text that excludes all gear ranges not normally used for on road operation. This proposal was adopted at WLTP IG #8, but the wording needs to be improved regarding “range” (B. Coleman, Drafting Coordinator).
Exclusion of auxiliary gears 11 The issue to exclude crawler gears from the gear use calculation is still under discussion. The crawler gear is an occasional use gear for heavily laden conditions, steep hill starts or maintaining a very slow controlled speed when laden. A crawler gear is very similar to the ‘low range’ transfer boxes used on off road vehicles (see issue 1. on previous slide). The main problem is to define delimination criteria for the crawler gears and the 1. gear for normal operation, that are performance based rather than design based. Special attendance has to be drawn to prohibit, that the requirements enable to skip the 1. gear for high powered sports cars.
Exclusion of auxiliary gears 12 Proposals from Nick Arden and the Japanese colleagues are currently discussed in the task force, but the task force concluded that more time for further discussions is needed. The WLTP IG extended the timeframe at its meeting #8 till WLTP IG #10.
OIL #6, annex 2, section OIL #6, annex 2, section 3.2, determination of engine speeds The current text is not precise enough and needs to be amended. An improved text was developed by the task force and presented at WLTP IG #8. The text amendments were adopted by WLTP IG at ist meeting #8.
OIL #6, annex 2, section OIL #6, annex 2, section 3.3, calculation of available power The possibility to apply an additional safety margin to the full load power curve at certain engine speed sections was required by India and some vehicle manufacturers. A modified version of the initial proposal made by Henrik Malberg was adopted in the task force and presented at WLTP IG #8. This proposal was adopted by the WLTP IG.
OIL #8, review 3 s rule for acc phases 15 This issue was requested by a N1 manufacturer, because the 3 s rule could lead to too high engine speeds for vehicles with „short“ transmissions, especially for the 1. gear. The task force discussed this issue extensively and came up with the proposal to change the 3 s rule to a 2 s rule already in an early stage of the discussions, because this change could ease the prescriptions significantly with respect to other requirements (e.g. skipping of gears) and does not lead to significant changes in the engine speed distributions. This proposal was presented at the WLTP IG #8 and adopted.
Further improvements of annex 2 16 But apart from this, the text in annex 2 of the GTR needed to be amended for clarity reasons. These amendments were elaborated by the task force leader and presented to the WLTP IG at meeting #8 (see WLTP-08-14e rev1). These amendments were adopted by the WLTP IG.
Gearshift prescriptions using torque meter method results 17 Another point on the issues list (OIL #7) is related to the use of road load coefficients in the gearshift calculation formulas. Add calculation formulas based on road load values from the torque meter method The problem was clarified between Japan and HS (coast down method delivers f0, f1 and f2, torque meter method delivers C0, C1 and C2). This issue should be dealt with in the annex 4 task force in conjunction with OIL #16.
Gear shift family criteria 18 A further point is listed in the OIL: Development of gear shift family criteria, see OIL # 9 This issue was discussed in the task force with the conclusion, that it is not necessary and thus can be deleted from the OIL. This proposal was presented to the WLTP IG at meeting #8 and was adopted.
Next meeting of the task force 19 The next meeting of the task force is scheduled for 4 th February 2015.