柴油中溶入甲烷对发动机燃烧排放特性的影响

设计了几种不同甲烷含量的甲烷／柴油混合燃料,在实用柴油机上对它们的燃烧和排放特性进行了试验研究。研究结果表明,根据柴油中甲烷含量的不同,溶气对比油耗和热效率有正反两方面的影响;溶有甲烷的柴油与纯柴油相比有较长的着火滞燃期和较低的最大放热率;柴油中甲烷的溶解量越大,滞燃期越长,最高放热率越低;与纯柴油相比,溶有甲烷柴油的NOx排放降低,HC排放增加;在较高的甲烷溶解度时,NOx和烟度排放能够同时降低。

Influence of Dissolved CH4 in Diesel Fuel on Engine Combustion and Emissions

Several blended fuels with different CH4 concentration in diesel fuel were designed, and the experiments on their combustion and emission characteristics were carded out on practical diesel engine. The study shows that the dissolved CH4 plays positive or negative influence on the brake specific fuel combustion and the thermal efficiency depending on the CH4 concentration in diesel fuel. Diesel fuel with CH4 dissolved in conduces to longer ignition delay and lower maximum heat release rate than that of pure diesel fuel. The more the concentration of CH4 in diesel fuel is, the longer ignition delay and the lower maximum heat release rate will be. The diesel fuels containing dissolved CH4 give lower NOx emission and higher hydrocarbon emission than those of pure diesel fuel. For the blended fuel with high CH4 concentration, both NOx and smoke emissions decrease simultaneously.