Prospects on Fuel Economy Improvements for Hydrogen Powered Vehicles

Fuel cell vehicles are the subject of extensive research and development because of their potential for high efficiency and low emissions. Because fuel cell vehicles remain expensive and the demand for hydrogen is therefore limited, very few fueling stations are being built. To try to accelerate the development of a hydrogen economy, some original equipment manufacturers (OEM) in the automotive industry have been working on a hydrogen-fueled internal combustion engine (ICE) as an intermediate step. Despite its lower cost, the hydrogen-fueled ICE offers, for a similar amount of onboard hydrogen, a lower driving range because of its lower efficiency. This paper compares the fuel economy potential of hydrogen-fueled vehicles to their conventional gasoline counterparts. To take uncertainties into account, the current and future status of both technologies were considered. Although complete data related to port fuel injection were provided from engine testing, the map for the direct-injection engine was developed from single-cylinder data. The fuel cell system data represent the status of the current technology and the goals of FreedomCAR. For both port-injected and direct-injected hydrogen engine technologies, power split and series Hybrid Electric Vehicle (HEV) configurations were considered. For the fuel cell system, only a series HEV configuration was simulated.