气门重叠角度对内燃机换气过程的影响规律研究  

Influence of Valve Overlap on Air Exchange Process in Internal Combustion Engine

作　　者：尚勇[1] 刘福水[1] 陆滢[1] 王亚丽[1] 

机构地区：[1]北京理工大学机械与车辆学院,北京100081

出　　处：《内燃机工程》2015年第4期104-111,共8页Chinese Internal Combustion Engine Engineering

基　　金：国家部委预研项目(40402020101);中国博士后科学基金资助项目(2013M530533)

摘　　要：结合模拟仿真和试验方法,对气门重叠角在某发动机较高转速外特性工况点下对发动机性能的影响规律和作用机制进行了研究。分析可知,排气门晚关角过小将导致进气初期发生倒流且使得排气末期流动损失加剧,而排气门晚关角过大将使排气末期的废气倒流加剧且使得进气初期的进气不畅;进气门早开角过小将使得进气初期的正向流动损失加剧且使得排气末期发生倒流,而进气门早开角过大将使得进气初期发生倒流。研究结果表明:最佳排气门晚关角和进气门早开角的选取原则分别为总排气量最大和进气开启流速为零,根据优化结果指导加工出配气凸轮轴并在发动机台架上进行试验,功率、扭矩等动力性指标提高约2%,充量系数和循环进气量提高约5%,证明了仿真计算方法的准确性和有效性。Combining simulation and test methods,the impact law and mechanism of valve overlap angle to engine performance under full speed and full load conditions were studied.From simulation result,a small exhaust valve closing angle leads to intake backflow at the beginning of intake stroke and increased exhaust flow loss at the end of exhaust stroke,while a big exhaust valve closing angle leads to exhaust backflow at the end of exhaust stroke and increased intake flow loss at the beginning of intake stroke.On the other hand,a small intake valve opening angle leads to increased intake flow loss at the beginning of intake stroke and exhaust backflow at the end of exhaust stroke,while a big intake valve opening angle leads to intake backflow at the beginning of intake stroke.The optimal exhaust closing angle and intake opening angle are justified by the maximum total exhaust flow and zero speed at intake opening.The intake and exhaust cams which are optimized and machined as per the results of the calculation are tested on engine test bench to verify the calculation.The test result shows that the power and torque at the targeted condition are increased by about 2percent,and charge coefficient and air intake by about 5percent,which proves the accuracy and validity of this calculation method.

关 键 词：内燃机 气门重叠角 作用机制 判断准则 

分 类 号：TK101[动力工程及工程热物理—热能工程]