车用汽油机瞬变过程性能检测与分析  

Detecting and Analysis of the Performances of an Automotive Gasoline Engine Under Transient Operating Conditions

作　　者：付建勤[1,2] 刘敬平[1,2] 何廷谱 夏言[1,2] 赵智超[1,2] 

机构地区：[1]湖南大学汽车车身先进设计制造国家重点实验室,长沙410082 [2]湖南大学先进动力总成技术研究中心,长沙410082

出　　处：《内燃机工程》2016年第5期128-133,139,共7页Chinese Internal Combustion Engine Engineering

基　　金：国家自然科学基金项目(51376057);国家"八六三"高技术研究发展计划项目(2012AA111703;2012AA111801)

摘　　要：基于动态压力实测与数值模拟相结合的方法,对一台乘用车汽油机瞬变过程进行连续检测,得出汽油机瞬变工况下多项运行参数与性能参数的变化规律,在此基础上剖析了诸多参数的内在联系。研究结果表明:高压循环平均指示压力(IMEP)和净平均指示压力(NMEP)在低负荷时稳定性较好,在高负荷时由于过量空气系数和点火提前角控制不准而产生较大波动;PMEP在低负荷时比较稳定,此时主要由排气与进气压力差决定;在高负荷时,泵气平均有效压力(PMEP)远大于排气与进气压力差并呈现波动变化;高负荷时,缸内残余废气系数(RGF)主要由进气压力决定,进排气阀可变气门正时(VVT)的影响很小;高压循环热效率在高负荷时波动明显,其峰值出现在低负荷,这主要受点火提前角的影响。Based on the method of combining dynamic pressure measurement with numerical calculation, the performance and operating parameters of a passenger car gasoline engine, were tested under transient operating conditions. On this basis, the change rules and internal relations between these parameters were analyzed. The results show that, the high-pressure cycle indicated mean effective pressure （IMEP） and net mean effective pressure （NMEP） are stable at low-load and tend to fluctuate at high-load due to the inaccurate excess air coefficient and the fluctuation of ignition advance angle. While the pumping mean effective pressure （PMEP） is stable at low-load and mainly depends on the differential pressure between exhaust gas and intake gas, which is much larger than the differential pressure between exhaust gas and intake gas at high-load and also turns to fluctuate. At high-load, the in-cylinder residual gas fraction （RGF） mainly depends on the intake pressure, while the effects of intake and exhaust variable valve timing （VVT） are very limited. The high-pressure cycle thermal efficiency fluctuates at high-load and its peak value appears at low-load, which is mainly caused by the ignition advance angle.

关 键 词：内燃机 汽油机 瞬变工况 泵气损失 热功转换效率 

分 类 号：U464.171[机械工程—车辆工程]