徐思鹏，何邦全，付雪青，赵华.直喷二甲醚对稀汽油混合气燃烧过程影响的研究[J].内燃机工程,2018,39(4):67-72.
直喷二甲醚对稀汽油混合气燃烧过程影响的研究
Effect of DME Direct Injection on the Combustion Processes of Lean Gasoline Mixture in an Engine
DOI：10.13949/j.cnki.nrjgc.2018.04.011
关键词:空气稀释  汽油机  二甲醚  燃烧
Key Words:air dilution  gasoline engine  dimethyl ether  combustion
基金项目:国家重点基础研究发展计划项目（2013CB228403）
作者单位
徐思鹏，何邦全，付雪青，赵华 天津大学 内燃机燃烧学国家重点实验室，天津 300072 
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摘要:在一台四冲程单缸汽油机上，通过缸内直喷二甲醚（DME）实现了空气稀释汽油混合气的稳定燃烧。研究结果表明：在1500r/min下，固定循环燃油热值时，直喷DME可以降低汽油机稀燃下的循环变动，加速初期火焰发展速度，缩短燃烧持续期，提高汽油稀燃稳定燃烧的过量空气系数上限。稀燃和直喷DME相结合可以改善发动机在稀燃下的燃油经济性。与理论空燃比混合气相比，稀燃能使指示燃油消耗率最多降低11.7%。改变点火时刻和直喷DME比例能实现不同过量空气系数下的最佳燃烧相位。随着过量空气系数的增加，最佳放热中心相位提前。
Abstract:The stable combustion of the air-diluted lean gasoline mixture was achieved with dimethyl ether(DME) direct injection in a 4 stroke single cylinder gasoline engine. Results show that the DME direct injection at 1 500 r/min and a fixed fuel low heating value in a cycle can stabilize combustion, accelerate initial flame propagation speed, shorten combustion duration and expand the upper limit of excess air coefficient(λ) in the lean burn conditions. The combination of lean burn and DME direct injection can improve engine's fuel economy under lean burn conditions. Compared to the stoichiometric mixture, the indicated specific fuel consumption can be decreased by up to 11.7%. The optimum combustion phases under different λ can be realized by changing the spark timing and the DME-to-gasoline ratio, meanwhile , the optimum heat release center will be advanced with the increase of λ.
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