MEASUREMENT OF RUNNING RESISTANCE BY TORQUEMETER METHOD. A.Müschen, E.Dewulf, P. Bailey, C.Hosier

MEASUREMENT OF RUNNING RESISTANCE BY TORQUEMETER METHOD A.Müschen, E.Dewulf, P. Bailey, C.Hosier

Measurement of Running Resistance Chassis-Dynamometer Setting Comparison Torquemeter Method / Coastdown Method 2 11/12/2012 Torquemeter-Coastdown_Comparison of Methods

TORQUEMETER METHOD Torquemeter in the drive-train of test vehicle to measure running resistance Wheel Position of Strain Gauges Brake Disc Adapter Preferably: measure running resistance at the rims of each of the driven wheels Torquemeter Measuring Device Excluding effects of powertrain / transmission / vehicle inertia during measurement Instrumentation of vehicle w/o affecting running resistance (aerodynamic drag) special set of rims and adapter rings signal transfer to data collection device, preferably wireless difficult / time consuming 3 11/12/2012 Torquemeter-Coastdown_Comparison of Methods

MEASUREMENT OF RUNNING RESISTANCE - ROAD TESTING (1) Vehicle conditioning: Preconditioning and Stabilization of vehicle at the speed where the running resistance is to be measured Torque Measurement / Data Collection (ISO 10521-1): Record at least 10 data sets of speed/torque/time for min. 5 seconds, see table Calculate mean speed and torque Assess accuracy of measurement Repeat torque measurement on the track in both directions to have at least 4 consecutive results with sufficient accuracy 4 11/12/2012 Torquemeter-Coastdown_Comparison of Methods

MEASUREMENT OF RUNNING RESISTANCE - ROAD TESTING (2) Torque Measurement / Data Collection (ISO 10521-1): Determine Running Resistance Curve Correct to Standard Atmospheric Conditions 5 11/12/2012 Torquemeter-Coastdown_Comparison of Methods

Measurement of Running Resistance Chassis-Dynamometer Setting Comparison Torquemeter Method / Coastdown Method 6 11/12/2012 Torquemeter-Coastdown_Comparison of Methods

LOAD SETTING OF CHASSIS DYNAMOMETER (1) Evaluate Dyno Setting to provide same torquemeter readings vs. speed as measured on the road ( running resistance ) Wheel Position of Strain Gauges Brake Disc Adapter Vehicle is fitted with the same Torquemeter Measuring Device instrumentation as on the road Preconditioning and Stabilization of vehicle at the desired speed Dyno Adjustment / Data Collection: Record at least 10 data sets of speed/torque/time for min. 5 seconds, see table 7 11/12/2012 Torquemeter-Coastdown_Comparison of Methods

LOAD SETTING OF CHASSIS DYNAMOMETER (2) Dyno Adjustment / Data Collection: Calculate mean speed and torque Wheel Position of Strain Gauges Brake Disc Adapter Assess accuracy of measurement Repeat torque measurement to have at least 4 consecutive results with Torquemeter Measuring Device sufficient accuracy Determine Road Load Resistance Curve Verify road load setting, error of simulated road load to be < 10% up to 20km/h, < 5% up to 50 km/h, < 3% else if required: Adjustment of dynamometer coefficients & new Iteration 8 11/12/2012 Torquemeter-Coastdown_Comparison of Methods

Chassis dynamometer setting process Verification Vehicle, Dyno Tyre Details

Measurement of Running Resistance Chassis-Dynamometer Setting Comparison Torquemeter Method / Coastdown Method 10 11/12/2012 Torquemeter-Coastdown_Comparison of Methods

ROAD LOAD COMPARISON C/D MATCH VS. TORQUEMETER METHOD (1) Road load comparison between the torque method and the coast down method Tyre Rdyn. Weight IWC Track Torque (Nm) Dyno load (N) Coast Down Data derived from Dyno Settings ( sec ) a b c F0 F1 F2 125-115 115-105 105-95 95-85 85-75 75-65 65-55 55-45 45-35 35-25 25-15 TOTAL (m) (kg) (kg) 120 110 100 90 80 70 60 50 40 30 20 235/50R18 0,336 1768 1810 62,0 0,091 0,01349 102,1-0,015 0,0405 5,83 6,58 7,45 8,48 9,68 11,09 12,70 14,53 16,53 18,60 20,56 132,03 Tyre Rdyn. Weight IWC Track Coast Down Data ( sec ) 125-115 115-105 105-95 95-85 85-75 75-65 65-55 55-45 45-35 35-25 25-15 TOTAL (m) (kg) (kg) 120 110 100 90 80 70 60 50 40 30 20 235/50R18 0,336 1768 1810 5,77 6,53 7,40 8,44 9,64 11,07 12,70 14,54 16,56 18,64 20,60 131,89 Speed [km/h] 120 110 100 90 80 70 60 50 40 30 20 calc. Force, based on TorqueMeter Method, [N] 862,4 764,1 674,9 592,9 519,4 453,4 395,9 346,0 304,2 270,3 244,5 calc. Force, based on Track Coast Down Method, [N] 871,4 770,0 679,4 595,7 521,6 454,2 395,9 345,8 303,6 269,7 244,1 Force Difference (TorqueMeter - Track c/d) [N] -9,0-5,9-4,6-2,8-2,2-0,8 0,0 0,2 0,6 0,6 0,5 rel. Difference [%] -1,0-0,8-0,7-0,5-0,4-0,2 0,0 0,1 0,2 0,2 0,2 time Difference (TorqueMeter - Track c/d) [sec] 0,060 0,050 0,050 0,040 0,040 0,020 0,000-0,010-0,030-0,040-0,040 0,140 rel. Difference [%] 1,0 0,8 0,7 0,5 0,4 0,2 0,0-0,1-0,2-0,2-0,2 0,1 1. Torquemeter method as described above was applied for creation of Dyno Settings 2. Dyno Settings were used for coastdown on the dyno ( Coast Down Data derived from Dyno Settings ) 3. Coastdown Method was applied on the track for reference ( Track Coast Down Data ) 4. Comparison of Total Resistance ( calc. Force ) and coastdown times ( time ) No significant difference found between the two methods! 11 11/12/2012 Torquemeter-Coastdown_Comparison of Methods

ROAD LOAD COMPARISON C/D MATCH VS. TORQUEMETER METHOD (2) 900 800 700 600 Total Resistance [N] 500 400 Torquemeter Datenreihen1 Datenreihen2 CoastDown 300 200 20 30 40 50 60 70 80 90 100 110 120 No significant difference found between the two methods! Speed [km/h] 12 11/12/2012 Torquemeter-Coastdown_Comparison of Methods