An Optimization Approach to Hybrid Electric Propulsion System Design

Environmentally friendly ground vehicles with range and performance capabilities surpassing those of conventional ones require a careful balance among competing goals for fuel efficiency, performance, and emissions. One research activity at the Automotive Research Center is to integrate hybrid electric vehicle simulations with high-fidelity engine modules to increase the accuracy of predictions and to allow design studies in the concept evaluation stage. This article describes a method4ology for integrating vehicle and engine simulations. The feed-forward model of the engine simulation is modified to allow its linking with the vehicle model, and an engine component scaling routine is added to facilitate system sizing studies. A design optimization framework is then used to find the best overall engine size, battery pack, and motor combination for minimum fuel consumption within proposed US government performance criteria.