中文摘要：

在一台6缸重载车用增压中冷柴油机上，进行进气管改装，采用向内喷入掺水乙醇（水的体积分数为30%）的方式，实现柴油/掺水乙醇二元燃料组合燃烧（DECC）。研究了稳定工况下，掺水乙醇不同比例替代柴油（替代率分别为0%、30%、40%、50%、60%）对发动机燃烧特性和经济性的影响。研究结果表明：与纯柴油相比，随着替代率的增加，二元燃料燃烧的滞燃期延长，最大放热率增加，缸内压力峰值升高，燃烧持续期缩短。低转速时，当量比油耗最高降幅达13%，热效率最大升幅为8.3%；高转速时，当量比油耗变化不大，乙醇替代率超过30%时，发动机燃油经济性甚至会出现轻微恶化。

英文摘要：

Experiments were carried out on a turbo-charged, inter-cooled, heavy duty truck’s 6 cylinder diesel engine; ethanol-water blends （the volume fraction of water is 30%） were injected to the retrofitted intake pipe to realize diesel/ethanol water blends compound combustion. The combustion characteristics and economic efficiency at several kinds of speeds and loads with different high diesel substitution rates （0%, 30%, 40%, 50% and 60%） were investigated in steady working condition. The results show that, compared with normal combustion mode, the diesel/ethanol-water blends compound combustion lead to the ignition timing delay, maximum rate of heat release and in cylinder pressure peak rise, combustion duration shorten. When the engine work in low speed, the equivalent specific fuel consumption most decreases by 13%, and the effective thermal efficiency most increases by 8.3%; in high speed, the equivalent specific fuel consumption remains approximately constant, and the fuel economy can even be deteriorated slightly when the diesel substitution rates are more than 30%. The results can be used to guide the application of diesel/ethanol compound combustion in engine.