Evaluation of Real-World Activity, Energy Use, and Emissions of A Plug-In Hybrid Electric Vehicle

摘要

The fuel use and energy use for a PHEV Prius Plug-in was measured during real-world operation. The vehicle was observed to travel approximately 12.6 miles in CD mode. In CD mode on Route C, the engine was on for 10% of operational time, whereas in CS mode on the selected routes, the engine was on for 57% of operational time. The combined gasoline and grid electricity energy economy was lower for CD mode versus CS mode. Combined energy economy was higher for arterial driving than for highway driving. The observed energy economy reported here is based on actual fuel use of the engine and the energy input required generating electricity taking power plant efficiency and transmission loss into account. The energy economy reported here is much lower than the 95 MPGe rating assigned by EPA, which does not take into account actual grid energy input. Combined CO_2 emission factors were similar in CD and CS mode. Combined CO, HC, NO_x, and SO_2 emission factors were higher in CD versus CS mode for the particular regional electricity generation fuel mix. The tailpipe emissions observed during CD mode were higher than for CS for routes, indicating that the engine and catalytic converter were undergoing a cold start during the brief episode of engine operation in the midst of CD mode. The cold start is a likely factor influencing the relatively high magnitude of CO, HC, and NO_x emissions during CD mode. However, the combined emissions of NO_x and SO_2 during CD mode would have been higher than for CS even if the vehicle was hot stabilized, because of the significant contribution from grid-based emissions from the regional electricity generation fuel mix. The results could differ depending on the electricity generation mix. VSP is an effective engine load parameter for estimating variability in fuel use rates in CS mode, and TB electricity use.