An idea how to handle wind tunnel & chassis dyno method for WLTP gtr

1. WLTP-DTP-LabProcICE-207 An idea how to handle wind tunnel & chassis dyno method for WLTP gtr JAPAN

2. Analysis of EADE data Roughly, 0.010 - 0.015 correlation difference by different vehicle is observed. Generally absolute Cd number is estimated around 0.4, thus relative deviation is 3 - 4 %. A 3 - 4% difference is observed from the data within 8 labs & 11 vehicles.

3. Consideration of RL data deviation ICE#166, from UTAC ICE#176-2, from Ford B C D Repeatability Approx +/- 2% (2sigmas) E WT+ChDy data is used only for correction of RL from coast down. (2～4%, estimated dev of RL) 4% B E D 2% Either WT+ChDy or coast down can be used as official RL, with evaluation of correlation by each vehicle shape (or appropriate family of vehicle shape) (6~9%, estimated dev of RL) 2～5% C 4% 3～4% A Either WT+ChDy or coast down can be used as official RL, with evaluation of correlation by only one vehicle shape. (9~13% or more, estimated dev of RL) C 4% This deviation is estimated from the data within 8labs & 11 vehicles. There is uncertainty of deviation in case of more labs & vehicles data.

4. Consideration how to handle WT+ChDy Approx 12% Current CO2 gap is one of the sample to show future uncertainty and flexibility is used for better result only. Safety approach needs to be considered to prevent this error from making again. On the other hand, W/T+C/D has been approved and handled in EU. Japan need to know how they do it.

5. Current situation of wind tunnel & chassis dyno method • Technical Service A • W/T+C/D is only used for correction of the data from coast down. • Approval criteria of W/T+C/D is within 5% correlation with coast down. • Technical Service B • W/T+C/D is only used for correction of the data from coast down. • No approval criteria, but correction is limited to minor shape change. If vehicle body is different, the base data from coast down is necessary. • Background • There are uncertainties what parameter of W/T equipment affect to the result. T/S has already used the data from W/T+C/D. However there is restriction because they have concern same as JPN.

6. An idea of initial proposal for WLTP gtr Slide 4, ICE lab proc #184 • Consideration • Until the technical logic is established (e.g. what parameter of W/T+C/D affect the result), the data from W/T+C/H method should be limited to avoid wider variation of road load data. • There are uncertainties of correlation with current official method (i.e. coast down) in combination with vehicle body shape and W/T+C/H equipment. • In history, W/T+C/D method has been used for correction of road load obtained from real running methods (i.e. coast down), in case of minor body shape change (i.e. different parts/feature, not whole body shape) .

7. Japanese position • Limited use of W/T+C/D data, for correction only (in Phase-1). • Since there is no technical logic what/how parameter of W/T+C/D equipment affect the test result, we do not know how much deviation exist in case of more labs & vehicles data. • On the other hand, “correcting RL data of coast down” by W/T+C/D data has already been used at European Technical Service. • ‘Torque-meter method’ data is also corrected by W/T+C/H data to obtain the other R/L with parts/feature difference. Since vehicle friction measured by ‘Torque-meter method’ and ‘coast down method’ is generally different (brake drag is counted or not), individual correlation data is necessary. • Uncertainty: Torque-meter method measures “Torque”. W/T+C/H method can measure torque instead of force? • Supplemental item: • Same method shall be used at both of RLD and dyno set procedure of RL • If coast down method is used for RLD, that method shall be used for dyno set procedure. Torque-meter method is also as well.) • Vehicle friction measured by ‘Torque-meter method’ and ‘coast down method’ is generally different (brake drag is counted or not).