Model-based systems analysis of a hybrid fuel cell vehicle configuration

This paper demonstrates the application of systems engineering methods through a model-based analysis of a fuel cell vehicle. It is well known that an on-board fuel reformer for an indirect methanol based fuel cell system imposes a performance limitation on the vehicle due to the reformer lag. An auxiliary power source (APS) can be used in the vehicle to alleviate this performance limitation. This paper explores the tradeoff between vehicle performance and energy capacity of the APS system for several battery technologies and reformer lags using model-based simulation. It is shown that for a given vehicle, motor and fuel cell system configuration, there is an optimal choice for the APS energy capacity for different APS (battery) technologies. Based on unit costs associated with the battery technologies, the analysis is extended to include cost factors in the APS system selection process. More importantly, the analysis procedures demonstrated in this paper are generic and can be applied to other problems of similar kind to derive systems engineering based solutions before building hardware prototypes.