直馏和催化汽油组分在汽油机燃烧过程中的可用能分析

Availability analysis of composition of straight run and catalytic cracking gasoline during combustion process of gasoline engine

根据调合燃油在汽油机燃烧过程中能量的转化规律,建立调合燃油组分模型及热力学准维双区模型,模拟研究直馏汽油和催化汽油在汽油机燃烧过程中缸内工质可用能及不可逆损失的变化规律。在调合燃油组分模型中,将异辛烷、正庚烷、甲基环己烷及甲苯作为直馏汽油的替代组分,将异辛烷、正庚烷、甲基环己烷、甲苯以及1-戊烯作为催化汽油的替代组分。结果表明:催化汽油的总可用能损失较低,约为36.01%,而直馏汽油的可用能损失较高,约为40.07%;在整个燃烧阶段,催化汽油的传热引起的可用能损失比直馏汽油的高,而燃料燃烧引起的可用能损失较低;可用能损失的大小与调合燃油组分组成的种类以及燃油组分组成的含量有关。

According to the transformation regularity of fuel energy in the gasoline engine combustion process with blended gasoline,the fuel blending component model and the thermodynamic quasi-dimensional two-zone model were established.The changes of availability and loss of irreversibility as a function of crank angle during the combustion process with straight run gasoline and catalytic cracking gasoline were studied by numerical simulation respectively. In the fuel blending component model,i-octane,n-heptane,methyl cyclohexane and toluene were treated as the substitute for straight run gasoline components,simultaneously,i-octane,n-heptane,methyl cyclohexane,toluene and 1- pentene as the substitute for catalytic cracking gasoline. The results show that the total exergy destruction of the catalytic cracking gasoline（ 36. 01%） was lower than that of the straight run gasoline（ about 40. 07%）. During the combustion process,the exergy destruction of the catalytic cracking gasoline due to heat transfer was larger than that of the straight run gasoline,while the exergy destruction due to combustion was smaller. The differences of the exergy destruction during the combustion process appear to be related to the kind and content of the hydrocarbon compositions in the blended gasoline.