增压GDI发动机全负荷工况扫气特性及气门正时策略优化研究  

Scavenging Characteristics and Valve Timing Strategy Optimization in Full Load of Turbocharged GDI Engine

作　　者：宋义忠[1] 胡玮[2] 石磊[2] 邓康耀[2] 孙卫清[1] 靳嵘[3] 

机构地区：[1]泛亚汽车技术中心有限公司,上海201201 [2]上海交通大学动力机械及工程教育部重点实验室,上海200240 [3]中国北方发动机研究所(天津),天津300400

出　　处：《车用发动机》2014年第4期49-54,共6页Vehicle Engine

基　　金：国家高技术研究发展计划("863"计划)资助项目(2012AA111702);国防重点实验室基金(9140C330203120C33120)

摘　　要：利用GT-Power软件建立仿真模型，开展了进排气压力波动分析，针对全负荷7个稳态转速点，研究了扫气量和进排气压差的关系，确定了可用扫气转速区域。分别在最大扭矩工况和标定功率工况探讨了气门正时对发动机性能的影响规律，并提出了全负荷工况气门正时优化策略。研究结果表明：在1000～2700 r/min转速范围内，排气上止点附近存在进排气正压差区，扫气系数大于1．03；在最大扭矩工况，增大气门重叠角，可使扫气系数增加，涡前排温明显下降；在标定功率工况，排气门关闭正时在353°A T DC附近时，残余废气系数最小。基于进气量优化气门正时，在全负荷6000 r/min处，进气量提高了19％，残余废气系数降低了0．018，功率提升了21％。在最大扭矩工况附近，增压压力提高了11．7％，涡前压力增大了19．4％。Based on the calculated model established by GT-Power software ,the intake and exhaust pressure fluctuation was analyzed .The speed range of available scavenging was determined by analyzing the relation of scavenging mass with intake and exhaust pressure difference in seven operating conditions .The effect of valve timing on engine performance was discussed in conditions of maximum torque and rated power and the optimization strategy of valve timing in full load was put forward .The results show that the positive pressure difference exists and the scavenging coefficient is 1 .03 near exhaust TDC in 1 000~2 700 r/min .In the maximum torque condition ,increasing valve overlap angle can increase the scavenging coefficient and the temperature before the turbine will decrease .In the rated power condition ,the coefficient of residual gas reaches the minimum when EVC is around 353°ATDC .After optimizing the valve timing ,the intake air mass increases by 19% ,the coefficient of re-sidual gas decreases by 0 .018 and the power increases by 21% in full load condition of 6 000 r/min .In the maximum torque condition ,the pressure after compressor improves by 11 .7% and the pressure before turbine increases by 19 .4% .

关 键 词：汽油机 配气相位 扫气 残余废气 

分 类 号：TK421.3[动力工程及工程热物理—动力机械及工程]