进气门晚关与高压缩比技术在汽油机上的应用

针对混合动力汽车用发动机的特点,通过模拟和试验相结合的方法,研究了进气门晚关与高压缩比对汽油机部分负荷性能的改善作用以及由于发动机参数变化对外特性的影响.研究结果表明:部分负荷应用进气门晚关与高压缩比可在排放变化不大的前提下使发动机油耗降低4%~10%;进气门晚关控制负荷有效降低了泵气损失,配合几何压缩比的提高和点火提前角的优化,实现了较好的燃烧性能,提高了膨胀比;综合作用下使得有效热效率提高;较长进气持续期和较大几何压缩比的应用使得外特性扭矩降低2%~5%的同时,油耗平均5%.

Application of Late Intake Valve Closure(LIVC)Strategy Combined with High Compression Ratio in a Gasoline Engine

Base on the needs of hybrid vehicle engines, this paper studies the effects of late intake valve closure（LIVC） strategy and compression ratio optimization on engine performance at part load, as well as the effects ofchanging engine parameters on full load performance through both simulation and experiment. The experimental resultsindicate that through combining LIVC with compression ratio optimization, the fuel consumption at part loaddecreased by 4%-10% when the emission keeps at a stable level. By raising the intake pressure in cylinder, LIVC cansignificantly reduce the pumping loss. And increasing the geometric compression ratio and spark timing optimizationresulted in better combustion efficiency and longer expansion ratio. The above effects combined result in a higherthermal efficiency. Meanwhile, the full load torque was lowered by 2%-5% while decreasing fuel consumption by 5%with the newly designed engine parameters.