Performance study of a four-stroke spark ignition engine working with both of hydrogen and ethyl alcohol as supplementary fuel

The effect of the amount of hydrogen/ethyl alcohol addition on the performance and pollutant emission of a four-stroke spark ignition engine has been studied. The results of the study show that all engine performance parameters have been improved when operating the gasoline spark ignition engine with dual addition of hydrogen and ethyl alcohol. The important improvements of alcohol addition are to reduce the NOx emission with increase in the higher useful compression ratio and output power of hydrogen-supplemented engine. The addition of 8 mass% of hydrogen, with 30 vol% of ethyl alcohol into a gasoline engine operating at 9 compression ratio and 1500 rpm causes a 48.5% reduction in CO emission, 31.1% reduction in NOx emission and 58.5% reduction in specific fuel consumption. Moreover, the engine thermal efficiency and output power increased by 10.1 and 4.72%, respectively. When ethyl alcohol is increased over 30%, it causes unstable engine operation which can be related to the fact that the fuel is not vaporized, and this causes a reduction in both, the break power and efficiency.