Normalizing Ambient Effects in xEV Powertrains of Varied Electrification Levels and Architectures

This study demonstrates how SAE standard J1349 ambient correction factors are applied across varied powertrain electrification levels and xEV architectures. To study this phenomenon, these powertrain were evaluated (in vehicle, real road) at varied ambient pressures and temperatures to observe performance changes. 0-100kph wide open throttle acceleration time results were reported as a proxy for power/torque figures normally produced on an engine test bench in controlled laboratory conditions (per J1349). Observing results, it is clear that minimal to no ambient effects are observed on powertrains of high electrification, sometimes requiring zero normalization. The challenge to low-mid electrification/hybridization testing is understanding how to apply SAE J1349 ambient correction factors to accurately normalize results. To accomplish this, an Energy Ratio Method was developed to identify energy contributions within the powertrains. The results are a more accurate normalized performance value that reflects what one would expect to achieve in varied ambient conditions. Caveats were discovered when working with different hybrid architectures. This results in a somewhat complicated relationship among the varied powertrain architectures. As a remedy, working guidelines were developed to assist in applying normalization to varied electrification levels, pressure charge vs naturally aspirated, and architecture types. These working guidelines continue to be evaluated, tested and updated for continual improvement and accuracy.