Fuel consumption and emission of SI engine fueled with H2-enriched gasoline

A study of the effect of the amount of hydrogen on the fuel consumption and emission of a spark ignition (SI) engine is reported. In the first stage, dynamometer test results for a wide range of engine speeds, engine loads, equivalence ratio, and hydrogen enrichment under steady-state operation were obtained, and the engine requirements for minimum BSFC were specified. In the second stage, an onboard, online hydrogen generator was developed and employed to provide the required amount of hydrogen. The hydrogen was produced by a steam reforming process. A detailed model for simulating a spark ignition engine fueled with hydrogen-enriched gasoline was developed and used to predict the optimal amount of hydrogen supplement as well as the corresponding MBT, optimal throttle position, and emissions level of CO, HC, and NO_x