Combustion diagnosis results show that when using methanol or ethanol fuel,the miniature internal combustion engine with glow-ignition has higher level of cyclic variations, lower rate of heat release and longer combustion duration.So,adding additives of nitromethane and hydrogen peroxide were investigated.With the additive of nitromethane,the start of combustion (SOC) is advanced,the combustion velocity is improved and the coefficient of variation is reduced.However,the combustion characteristics become poor when the hydrogen peroxide is added to the fuel.In order to analyze the effects of nitromethane on the combustion,experiments of adding different proportions of nitromethane to methanol fuel and ethanol fuel were investigated.Under the glow-ignition condition with alcohol fuels,the nitromethane affects its indicated mean effective pressure and characteristic of cyclic variation by the adjustment of SOC.Adding nitromethane makes the SOC advance and let the combustion duration shorten that lead to the decrease of cycle-by-cycle variation. While with high proportion of nitromethane,the SOC tends to become more dispersed and the cycle-by-cycle variations become more severe,which result in performance degradation.
