可变压缩比米勒循环汽油机热功转换效率预测及优化  

Theoretical Correction and Experimental Validation of the In-Cylinder Thermal Conversion Efficiency Prediction Equations of a Variable Compression Ratio Miller Cycle Gasoline Engine

作　　者：阳辉勇 张磊 谯俊豪 刘敬平 沈大兹 付建勤 Yang Huiyong;Zhang Lei;Qiao Junhao;Liu Jingping;Shen Dazi;Fu Jianqin(Research Center for Advanced Powertrain Technologies,Hunan University,Changsha 410082,China;Hunan Dazi Power Technology Company Limited,Changsha 410221,China)

机构地区：[1]湖南大学先进动力总成技术研究中心,湖南长沙410082 [2]湖南大兹动力有限公司,湖南长沙410221

出　　处：《内燃机学报》2024年第5期421-428,共8页Transactions of CSICE

基　　金：国家自然科学基金资助项目(51776061);广西科技重大专项资助项目(桂科AA23023014).

摘　　要：从理想热力循环出发推导,实现了有效压缩比与膨胀比之间的解耦,提出了相应的缸内热功转换效率预测方程.结果表明:所提出的方程能准确预测有效压缩比或膨胀比的变化对热功转换效率的影响规律.从导出的方程中还可得到膨胀比对热效率的影响大于压缩比的结论.通过分析不同压缩比条件下发动机的膨胀比以及热效率的试验结果,得到了中、高负荷下压缩比εECR(εECR≥8)太高对膨胀比乃至热效率反而不利的结论.有效压缩比与有效膨胀比解耦后的方程为二者的独立优化或协同优化提供了一条清晰、快捷有效的技术路线,发动机的台架试验验证了“低压缩比”、“高膨胀比”的优化理念.Prediction equations of the in-cylinder thermal-to-work conversion efficiency was corrected and proposed based on the ideal thermodynamic cycle and the decoupling between the effective compression ratioεECR and the effective expansion ratioεEER for a viable compression Miller cycle gasoline engine.Engine dyno validation tests indicate that the corrected equations could accurately predict both the values and the changing trends of the thermal conversion efficiency and its variation with theεECR and theεEER.By analyzing the test results of the expansion ratio and the thermal efficiency under different compression ratios,It is found that theεEER has much stronger influence on the thermal efficiency than theεECR.Also,too high compression ratio(εECR≥8)in medium to full load range could cause lowerεEER and lower thermal efficiency.The proposed equations provide a clear technical route to optimize theεECR and theεEER in the same time due to decoupling of theεECR and theεEER.Engine dyno tests also indicate that the concept of lowεECR but highεEER can significantly improve the thermal efficiency of the Miller cycle gasoline engines.

关 键 词：汽油机 有效压缩比 有效膨胀比 米勒循环 热功转换效率 

分 类 号：TK411.2[动力工程及工程热物理—动力机械及工程]