Fuel Consumption Modeling of Hybrid Vehicles in PERE

The new EPA emissions inventory model, MOVES (MOtor Vehicle Emissions Simulator) models fuel consumption of the on-road fleet in its first draft (2004 version). Future versions will model criteria pollutants. MOVES is designed to combine fleet, activity, and second by second emission rate inputs to produce regional, or national fuel consumption rates. It is primarily a data driven model but for some of the future projections, data is not available. It is necessary to design a model, which can fill these “holes” and future emissions rates in MOVES. The Physical Emissions Rate Estimator (PERE) takes vehicle and drive cycle inputs and simply distributes the energy required to follow the trace to the various components (internal combustion engine, electrical motor, fuel cell, etc). The model is validated to the certification fuel economy of the Honda Insight, Honda Civic, Honda FCX, Toyota Prius (2001, and 2004). It is also compared to a small subset of second by second data. While the model is capable of providing second by second output, it is not explicitly designed to be accurate to that level of detail. The cycle fuel economy is calculated to within 10% for most cases. In order to quantify modal fuel rates for MOVES from certain hybrids, it is recommended to shift the time-alignment of the data to a load-following pattern.