Update of SAE J2908 Activities Mike Duoba Argonne National Laboratory 19 October

SAE J2908 History J2907 – Motor Ratings J2908 – System Rating J2907/J2908 originally given SAE “J-doc” numbers more than 10 years ago, due to lack of progress, committee was tabled 2013: some meetings were held to restart J2907 Dec 2013: J2908 committee started recruiting members, regular monthly meetings in 2014 and 2015 July 2014: Argonne started doing exploratory chassis dyno testing March – July 2015: rented hub dyno for testing 2

Basic Elements of J Run a Test 2.Collect Data 3.Report Rating – Based upon test data & possibly other information 3 good progress problems

1. Run Test Prep requirements varied slightly for each HEV design (SOC and Temps) Found a few test procedure options to best achieve peak total powertrain power for different types of HEVs Hub dyno and chassis dyno (w/axle torque) were found to be equivalent 4 Hub Dyno Chassis Dyno Wheel or axle torque sensor needed for power direct power measurements or

Different Test Types Were Developed for Different Powertrain Operation 5 Road load mode Fixed-Speed mode Low-Inertia, High ABC loads Notes: - When speeds are changing quickly, inertia effects lower measured power. - Fixed Speed and Terminal Velocity tests are preferable.

2. Collect Data Measure DC electric power – from battery – From accessories Monitor Powertrain Parameters – Engine: RPM, MAP, MAF, injection timing, reported torque – Other: gear #, powertrain states, reported RPM and torques of motors Measure Axle or Wheel Power – May or may not be required 6 Current and Voltage Measurements Vehicle Network Data Dynamometer Data

3. Report Rating J2908 is Currently stuck here! Conflict between two objectives: – Value to Consumer (rating allows comparisons to other vehicles) – Ability to Verify (is information from OEM required?) Reporting options do not satisfy both objectives 7 Ability to Verify   Useful to Consumer (can compare to ICE Vehicles)

From What Information is the “Net System Power” Rating Reported?? 8 MG2 Any Configuration MG1 Eng Battery Acc Axle/Wheel Power measured Engine Power estimated + DC Power measured Engine Power estimated + DC Power measured Method  Shaft Powers estimated Three methods emerged

Deciding on a Solution If verifiability is of most importance, Method 3 will provide best data without reliance on estimations If 100% compatibility with conventional vehicle (engine-only) ratings are of most importance, Method 2 provides that rating Method 1 is partially compatible with existing ratings and partially verifiable 9

Application of Methods on Parallel HEV 10 Current OEM Catalog Ratings Engine: kW Motor: 30 kW (mechanical) Total: kW Method (1) = kW (engine rating + measured battery power) “Method (2) = kW (engine rating + reported motor power) Method (3) Total: 125 kW (measured axle kW) Elec meas = 35 kW Engine assumed to be at rated power here Motor est = 29 kW Time Axle meas = 125 kW Engine appears to be at rated power (from data) Method 1 and Method 2 are similar in value (small battery assist) As expected, Method 3 provides much a lower power rating than the other two.

Application of Methods on Series HEV 11 Current OEM Catalog Ratings Engine: kW Motor: kW Total: kW Method (1) = kW (rated engine kW + measured battery kW) Method (2) Series HEV output = only Motor kW Motor output: 124 kW (from CAN bus) Method (3) Total: 116 kW (measured axle power) Point at expected rated Eng kW - Peak fuel, peak RPM Motor est = 124 kW Axle meas = 116 kW Batt meas = 42 kW Engine appears to be at rated power (from data) Method 2: Total power = Motor Power (CAN bus RPM and torque) Method 1 and Method 2 are 23 kW different Method 2 and Method 3 are different by only 8 kW

Application of Methods on (another) Series HEV 12 Current OEM Catalog Ratings Engine: 63 kW Motor: 111 kW Total: 111 kW Method (1) = 141 kW (CAN bus engine kW + measured battery kW) Method (2) Series HEV output = only Motor kW Rated motor = 111 kW Method (3) Total: 105 kW (measured axle power) Engine power taken from CAN bus, motor power at rated power Method 1 has very high result, 30 kW higher than Method 2 80 kW 105 kW 61 kW

13 Final Issue: Processing Results All methods will require some filter applied to results Data signals must be filtered for robust result (avoid transient spikes or signal noise) Filter duration defines the duration period of peak power We must decide duration of filter size recognizing this choice is arbitrary but uniform Other viable methods besides window filter?

J2908 Summary / Conclusions Test procedures should be flexible to achieve highest and most representative peak power Hybrids are transient in nature, definition of power is linked to duration (filter size) Must resolve Key Issue: – Should hybrid rating be molded to fit current rating? – Should all vehicle power ratings switch basis to wheel/axle power 14