弧形机械挺柱在汽油机上的研究与应用

Study on the Application of Curved Mechanical Tappets on Gasoline Engines

机械挺柱是一种常见的气门机构,具有结构简单、刚度高及成本低的优点。平面挺柱不允许凸轮型线存在负曲率,而小包角大升程EIVC米勒循环凸轮型线往往存在负曲率,给凸轮型线设计造成很大困难。弧形挺柱与凸轮接触面为弧面,允许凸轮型线有负曲率,可以轻松实现小包角大升程EIVC米勒循环凸轮型线设计。基于EXCITE Timing Drive,进行弧形挺柱气门机构的凸轮型线设计及运动学动力学分析,对优化后的气门升程进行GT-POWER性能计算,并在某1.0L增压直喷汽油机上进行性能试验,最后进行耐久试验考察弧形挺柱的可靠性。

Mechanical tappet is a common valve mechanism,which has the advantages of simple structure,high stiffness and low cost.The negative curvature of CAM profile is not allowed in the plane tappet,while the negative curvature of CAM profile is often present in the small-angle high-lift EIVC Miller cycle CAM profile,which causes great difficulty in the design of CAM profile.The cam-contact surface of the curved tappet is arc surface,which allows negative curvature of the CAM profile,and can easily realize the design of small-angle and large lift EIVC Miller cycle CAM profile.Based on EXCITE Timing Drive,CAM profile design and kinematics and dynamics analysis were conducted for the curved tappet valve mechanism.GT-power performance calculation was conducted for the optimized valve lift,and performance test was conducted on a 1.0 L turbo-charged DI gasoline engine.Finally,durability test was conducted to investigate the reliability of the curved tappet.