Vehicle warm up and stabilisation RLD and dyno, AUDI
Vehicle warm up on the road Based on the proposal and the data shown in document LbP LabProcICE ICE#186 provided d by Japan we propose to drive the vehicle as follows: Cold vehicle:drive at 120 km/h (for low powered vehicles, 90 % of their respective vehicle max. speed until stable tbl conditions are reached hd This will depend on the following boundary conditions Type of vehicle, used Weather condition test track Vehicle, once warmed up : drive at 120 km/h (for low powered vehicles, 90 % of their respective vehicle max. speed.) until stable conditions are reached Justification: Small vehicles with small engines will have a different behaviour than bigger ones, big oval tracks and tracks with turning bays and ambient temperatures between 1 and 35 C require different procedures
Vehicle warm up on the dyno As the environmental conditions i on the dyno are not entirely comparable with ihthe conditions on the road, it is proposed to separate the requirements for conditioning on the road and on the dyno. Validation 2 results and BMW data have shown that t the examined class 3 vehicle was equally stable after a complete WLTC, 30 min@80 km/h and 15 min@120 km/h The vehicle shall be stabilised: Warm up the vehicle at the same speed used to stabilise for the road load determination. Warm up the vehicle until stabilised. This will depend on the following boundary conditions Type of vehicle, used Capacity of the proportional fan
Draft proposal for all vehicle classes On theroad: Cold vehicle: Warm up the vehicle with a steady speed (if possible) at 120 km/h until stable conditions are reached. Vehicles that are speed limited to lower speeds than required above shall be driven at [90 %] of their respective vehicle max. speed. It is recommended to warm up the vehicle for at least 20 min. Vehicle, once warmed up : Warm up the vehicle at 90 % of their respective vehicle max. speed until stable conditions are reached. If the manufacturer develops a different warm up cycle/procedure and equivalency can be shown, it shall be notified to the type approval or certification authority. On the dyno : Cold and warm vehicle: Warm up the vehicle at the steady speed used to stabilise for road load determination The vehicle shallbe warmed upuntil until stabilised, it is recommended to warm upcold vehicles for at least 20 min If the manufacturer develops a different warm up cycle/procedure and equivalency can be shown, it shall be notified to the type approval or certification authority. The highest appropriate gear shall be used
Stabilisation criteria for dyno load setting Cold and warm vehicle: Warm up the vehicle at the same speed used to stabilise for road load determination. Vehicles that are speed limited to lower speeds than required above shall be driven at [90 %] of their respective vehicle max. speed. The vehicle shall hllbe warmed up until stabilised. Dyno calibration criteria: The dyno load setting is deemed to be finished when two consecutive coastdowns are completed within the tolerance given below. With the given coast down times, a regression shall be calculated. The regression curve shall be within a tolerance of [±10 N] For a justification of the regression method see The LabProcICE document #192 by BMW (next pages)
WLTP ANNEX 4, LOAD SETTING TOLERANCE INTRODUCTION 1. Tolerances for the load setting shall be defined as an absolute value in Newton (e.g. +/- 10 N) over the whole speed range. 2. Due to continuously decreasing road loads (evolution) it will become harder and harder to meet the tolerances. An absolute value doesn t open up any flexibility but enables vehicles with automatic gear shift and also cars with a very small road load to meet the tolerances. 3. Tolerances should refer to the polynomial-curve and not to single points in order to meet the tolerance. 4. Is it possible for BEV / HEV / PHEV vehicles to meet this tolerance? WLTP Annex 4, Load Setting On Chassis Dyno, BMW, EG-63, 15.02.2013 Page 6
WLTP ANNEX 4, LOAD SETTING TOLERANCE MEASUREMENT WITH A MIDDLE CLASS AUTOMATIC CAR Deviation in Newton 25 20 15 10 5 0-5 -10-15 -20-25 single points regression upper tolerance lower tolerance upper tolerance NEW lower tolerance NEW 20 30 40 50 60 70 80 90 100 110 120 130 Vehicle speed in km/h Current tolerance can not be met due to automatic transmission. Tolerance becomes smaller with smaller road loads in the future and makes it even more difficult. An absolute tolerance gives more space at critical speeds but reduces flexibility in higher speeds. Making an regression before applying the tolerance, cuts peaks from automatic transmission. WLTP Annex 4, Load Setting On Chassis Dyno, BMW, EG-63, 15.02.2013 Page 7
WLTP ANNEX 4, LOAD SETTING TOLERANCE PROPOSAL Current proposal New proposal 7.1.3.2. The error, j, in per cent of the simulated road load F sj, shall be calculated using the method specified in A.1, for target road load F tj at each reference speed V j, using the following equation: Fsj Ftj j 100 Ftj F mj, obtained in Appendix I section 1.1, may be used in the above equation instead of 7.1.3.2. The error e s of the simulated road load F s shall be within +/- [10] Newton at the reference speeds V j. Calculate e s with the following equations: F sj. F = F - F for each reference speed V ej sj tj j Verify whether errors at all reference speeds satisfy the following error criteria in two consecutive coastdown runs, unless otherwise specified by regulations: The following regression curve shall be fit to the data sets (V j, F ej ) corresponding to all the speed points V j (j = 1, 2, etc.). j 3 per cent for V j 50 km/h j 2percentforV j 50 km/h j ej j 5 per cent for 20 km/h < V j < 50 km/h j 3 per cent for 20 km/h < V j < 50 km/h j 10 per cent for V j = 20 km/h See method at 4.2.1.4.5. If an error at any reference speed does not satisfy the criteria, 7.1.1.4. shall be used to adjust the chassis dynamometer load setting. e s = f 0e + f 1e * V + f 2e * V² If an error at any reference speed does WLTP Annex 4, Load Setting On Chassis Dyno, BMW, EG-63, 15.02.2013 Page 8
BACKUP
Stabilised conditions 30 min @ 80 km/h 140 CO 2 Vehicle stabilised 120 100 80 60 speed [km/h] 40 Engine torque 20 0 0 200000 400000 600000 800000 1000000 1200000 1400000 1600000 1800000 time [ms] Class 3 vehicle, 2.0 L gasoline engine, test mass 4000 lbs Operated at 80 km/h, the vehicle is stabilised after ~ 16 min
Stabilised conditions 15 min @ 120 km/h 140 CO 2 Vehicle stabilised 120 100 Engine torque 80 60 speed [km/h] s 40 20 0 0 100000 200000 300000 400000 500000 600000 700000 800000 900000 time [ms] Class 3 vehicle, 2.0 L gasoline engine, test mass 4000 lbs Operated at 120 km/h, the vehicle is stabilised after ~ 9 min