Technical Paper
Development of Benchmarking Methods for Electric Vehicle Drive Units
2024-04-09
2024-01-2270
As part of the U.S. Environmental Protection Agency’s (EPA’s) continuing assessment of advanced light-duty automotive technologies in support of regulatory and compliance programs, a 2018 Chevrolet Bolt electric drive unit (EDU) was benchmarked at the National Vehicle and Fuels Emissions Laboratory, NVFEL. The EDU was tested on a vehicle hub dynamometer, and engine dynamometer with and without its gear reduction to characterize its efficiency. Hub dynamometer testing was performed with brakes removed, and factory half shafts, driveline bearings and gear reduction in place. Engine dynamometer testing was performed with a drive unit modified to remove the gear reduction, so measurements taken were directly from the rotor’s output. The factory inverter was relocated in the dynamometer cell with the EDU, with a wiring harness tethering to a vehicle parked outside of the test cell. Full factory control of the EDU and inverter was maintained.