摘要
在一台1.5 L自然吸气汽油发动机上,通过调整进气门关闭时刻使发动机进气门延迟关闭(LIVC),从而降低发动机的实际压缩比,并配合不同的进排气门正时(VVT),对不同高膨压比循环对发动机性能的影响进行深入研究。研究结果表明:在部分负荷下,随着发动机膨压比的不断上升,发动机的燃油经济性总体上呈现先下降后上升的趋势。当膨压比为1.5时,发动机的燃油经济性达到最佳;当节气门全开时,随着膨压比的上升,虽然燃油经济性有明显改善,但由于实际进入发动机的混合气体积减小,发动机的动力性严重下降。在发动机转速为3000 r/min的外特性工况下,当发动机的膨压比从1升高至1.5时,其平均有效压力(BMEP)降低29.8,有效燃油消耗率降低10.5%。以上试验表明,通过LIVC实现的高膨压比循环,可以有效改善中低负荷下发动机的经济性能,但无法兼顾在极高动力需求下发动机的经济性能。
Based on a 1.5 L naturally aspirated internal combustion engine,the intake valves closure timing was delayed and the valve timing was adjusted,leading to a lower effective compression ratio.The effect of different expansion-compression ratio(ECR)on the performance of gasoline engine was studied.The result shows that,the brake specific fuel consumption(BSFC)is decreased at first and then increased with the ECR increased under the low load operation condition.When the ECR is 1.5,the BSFC reaches the lowest value.Under the full throttle condition,the BMEP decreases while the ECR increasing,but the brake mean effective pressure is further decreased.Under 3000 r/min external characteristics,the BMEP decreased 29.8 and the BSFC decreased 10.5%while the ECR increasing from 1 to 1.5.The high ECR achieved by LIVC could notably improve the thermal efficiency under the low and middle load conditions but not under the high load condition.
作者
树明亮
张振东
沈凯
屈卓燊
Shu Mingliang;Zhang Zhendong;Shen Kai;Qu Zhuoshen(University of Shanghai for Science and Technology,Shanghai 200093,China)
出处
《农业装备与车辆工程》
2021年第6期79-83,共5页
Agricultural Equipment & Vehicle Engineering
