汽油机曲轴箱通风系统的设计策略

Design strategy of gasoline engine crankcase ventilation system

基于汽油机曲轴箱通风系统的设计目标,阐述汽油机曲轴箱通风系统的功能与布置形式,建立曲轴箱通风系统的工作模型;结合流体特性和数学计算方法,提出活塞漏气量优化策略,分析汽油机曲轴箱真空度的影响因素,制定PCV阀的流量特性设计策略。利用汽油机模拟控制试验平台,进行活塞漏气量、曲轴箱真空度和PCV阀的流量特性等试验。试验结果表明:优化后活塞漏气流量最大值为14L/min,优化后的进气管和曲轴箱的真空度平均增加率分别为5.6%和8.0%,表明所制定的曲轴箱通风系统工作模型正确,提出的活塞漏气量、曲轴箱真空度和PCV阀的流量等优化策略可行。

Based on the design targets, the features and layout of the gasoline crankcase ventilation system were described, and the working model was established. Combing the fluid properties and the mathematical calculation method, the piston gas leakage optimization strategy was proposed, and through analyzing the influencing factors of the gasoline engine crankcase vacuum, the design strategy of the PCV valve flow characteristics was developed. Using gasoline analog control test platform, the leakage amount of the piston, the crankcase vacuum and PCV valve flow characteristics were experimented. The optimized maximum piston leakage flow is 14 IJmin, and the average increasing rate of the vacuum in the optimized intake pipe and crankcase is 5.6% and 8.0%. The working model of the crankcase ventilation system is right, and the proposed piston leak amount, crankcase vacuum and PCV valve flow optimization strategy are feasible.