可变进气门升程对汽油机泵气损失的控制及对燃烧过程的影响

摘要

为了降低汽油机部分负荷泵气损失,改善燃油经济性,在自主开发的进排气门升程和相位全可变的4VVAS(4 variable valve actuation system)单缸汽油机上开展了可变进气门升程控制负荷的试验研究,研究了进气门升程对进气量和负荷的控制作用以及进气门升程控制对泵气损失以及燃烧过程的影响,比较分析了采用可变进气门升程对汽油机性能的影响.研究结果表明.保持节气门全开,通过采用进气门升程调整的负荷控制方式,与节气门控制负荷方式相比,部分负荷的泵气损失可以降低20%～30%,指示燃油消耗率降低3%～12%,中低转速下机械损失也有所降低.但是燃烧过程持续期会变长,影响了燃油经济性的进一步改善.%To reduce pumping loss of a gasoline engine during part load and improve fuel economy, tests were carried out on a single-cylinder research engine equipped with 4VVAS (4 variable valve actuation system)cylinder head, which can independently control intake and exhaust valve lifts and timings. Throttle-less load control strategy, namely intake valve lift adjustment and phase optimization, was employed in this paper to reduce pumping loss and improve fuel economy. Results show that, with intake vane lift load control adopted, pumping loss can be reduced by 20％-30％, fuel comsumption reduced by 3％-12％, and FMEP also reduced at medium and low speed.It is also shown from the test that combustion duration gets longer, which will restrict the improvement of fuel economy.