Analysis tool for fuel cell vehicle hardware and software (controls) with an application to fuel economy comparisons of alternative system designs

Fuel cell vehicles are widely seen as the most promising alternative to conventional combustion engine vehicles. The main motivations for replacing combustion engine technology through fuel cell technology are the reduction of vehicle emissions (down to zero emission vehicles if hydrogen serves as a fuel) and the improvement of fuel economy, reducing the amount of carbon dioxide released into the atmosphere.; Hydrogen as a fuel has many attractions but because it is not readily available, its use could limit the initial introduction of fuel cell vehicles.; This dissertation work addresses fuel cell vehicles with on-board fuel processors. The on-board fuel processor allows the use of (at ambient conditions) liquid fuels such as methanol and gasoline instead of gaseous or cryogenic hydrogen.; However, the on-board fuel processor increases the complexity of the overall fuel cell system and significantly increases warm up time (cold start ability). Hybridization seems to be one way to solve these problems associated with the use of an on board processor for liquid fuels.; The metric of comparison in modeling different types of fuel cell hybrid vehicles is fuel economy.; It is shown that hybrid concepts have a significant advantage in terms of fuel economy over load-following fuel cell vehicles. The exact savings depend largely on the vehicle configuration and controls. They are greatest for designs that directly link an ultra-capacitor with the fuel cell stack terminals.; This dissertation develops a new model of fuel cell vehicles. It has the following features: (1) Dynamic modeling of the fuel cell system and vehicle; (2) Separation of component models from control algorithms and assignment of control blocks to individual components; (3) Modeling of different fuel cell hybrid topologies; (4) Modeling of advanced hybrid systems (e.g. hybrids with ultra-capacitors as energy storage); (5) Use of Matlab-Simulink.; The overall structure of the model prepares it for the use in rapid prototyping processes.