Conversion and Performance Analysis of a Small Utility Vehicle Operating on Hydrogen Fuel

Hydrogen as a combustible fuel offers great promise as a renewable alternative to fossil fuels. Test platforms are an important step toward the commercialization of any renewable fuel, as they can highlight more efficient means of implementing new and enhancing existing technologies. One such platform involves the conversion of gasoline fueled engines to operate on gaseous hydrogen. Traditional means for converting an engine to operate on hydrogen consists of port injection with slight modification to the spark timing. Due to stringent emissions standards, control over the production of NO_x typically received precedence over volumetric efficiency and ultimately power output. This has been typically accomplished using very lean burn regimens. Through the advancement of computer control for injection systems, significant improvements have been made in the fuel delivery system resulting in better fuel mileage, emissions, and power output while using near-stoichiometric conditions. Highlighted in this paper is the conversion of a single cylinder, 2-seater utility vehicle with special emphasis on the direct injection system and performance results. The latter include operations on three fuels: gasoline, natural gas, and hydrogen. Generally the hydrogen-related components were able to be installed in the areas within the vehicle used for the original gasoline system. Experiences in designing a direct-injection system as well as the application of a computer-control system are described. Also contained are emissions comparisons to similar conversions as well as that of the pre-modified engine operating on gasoline.