将一台2105柴油机改装成进气预混发动机，研究DME预混比和冷EGR率对该发动机燃烧特性的影响。研究结果表明，随DME预混比增大，该发动机燃烧始点不断提前，最高爆发压力和最高燃烧温度不断增大，压力升高率曲线和放热率曲线呈现3个阶段，且放热率曲线整体前移；随冷EGR率增大，燃烧始点逐渐后移，最高燃烧温度和最高爆发压力逐渐降低，压力升高率曲线和放热率曲线均呈现3个阶段，且各阶段的峰值逐渐下降，峰值出现的位置也逐渐后移。%Experimental study on the effects of DME premixed ratio and cold EGR rate on the combustion characteristics was conducted in a PCCI (premixed charge compression ignition) engine modified from a 2105 diesel engine. Experimental results showed that, with the increase of DME premixed ratio, the igniting timing of the diesel PCCI engine advanced gradually, the maximum cylinder pressure and temperature increased gradually, the curves of pressure rise rate and heat release rate were presented in three stages, the overall heat release rate curve moved forward and the overall combustion duration shortened. With the increase of cold EGR rate, the igniting timing of the diesel PCCI engine delayed gradually, the maximum cylinder pressure and temperature gradually reduced, both of the rate of pressure rise curve and the heat release rate curve were presented in three stages, and the peak value of each phase gradually declined, the position where they occur also gradually delayed.
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