Performance and Emissions of a Hydrogen-Gasoline SI Engine

When hydrogen is added to a gasoline fueled spark ignition engine the lean limit of the engine can be extended. Lean burn engines are inherently more efficient and have the potential for significantly lower NOx emissions. Thus, the purpose of this paper is to investigate the effect of hydrogen addition to gasoline-air mixture on the performance and exhaust emission characteristics of a spark ignition engine. Six excess air ratios are used ranging from 0.8 to 1.5. The amount of hydrogen added is 18.5% and 30% by energy fraction. The test engine is operated at 1500 rpm. From the experimental observations, the effect of hydrogen addition on thermal efficiency, specific fuel consumption, cyclic variations of the indicated mean effective pressure (IMEP), and emissions of CO, unburned hydrocarbons and NOx are analyzed.