A prediction study of the effect of hydrogen blending on the performance and pollutants emission of a four stroke spark ignition engine

Considering energy crises and pollution problems today, investigations have been concentrated on decreasing fuel consumption by using alternative fuels and on lowering the concentration of toxic components in combustion products. In the present work a quasi-dimensional model was developed to study the effect of hydrogen blending on fuel consumption and pollutant concentrations. The results of the study show that the maximum improvement in engine thermal efficiency occurs at 8% hydrogen blending. The results also show that 10% hydrogen blending reduces CO concentration by 73.8% but the NO concentration increases by 100%. However the problem of increasing NO concentration was solved by operating the engine with lean mixture. Hydrogen blending also reduces the specific fuel consumption until about 6% blending, then the effect becomes marginal. (C) 1999 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.