Analysis And Optimization About The Valve-train Of Gasoline Engine

Valve Train plays a key role in the power performance and economy of the engine,with the development of the engine to high power and high speed,it is more demanding that it can be stable and reliable at high speed.And to make the kinematics and dynamics performance of valve train is good.The main contents of this paper are as follows:(1)This paper is about a gasoline engine with overhead camshaft,the kinematics and dynamics model on the valve train are built up,which is the valve train dedicated software.According to the requirements on the kinematics and dynamics performance of the valve train,Analyzing and find out the existing problems of valve train under the current cam profile.(2)Buffering and working sections of the cam profile are redesigned,simple harmonic motion for the buffer section and polynomial dynamic motion for the working section,with the design parameters of working section of the cam profile for orthogonal experiment design to get the best solution,then kinematics and dynamics analysis of the new cam profile are completed,the results show that kinematics and dynamics performance of the valve train are improved.In addition,it also analyzes the relationship between the valve clearance and the valve seating force.(3)Applying the AVL-BOOST software to establish the model of gasoline to do the performance simulation of the engine,by comparing the output performance of the original engine and the improved cam profile,the results show that the performance of the improved cam profile is much higher than that of the original engine,and the expected effect is achieved.In addition,and the engine performance(power)caused by the intake and exhaust advanced angle of the valve timing is discussed,the results show that by adjusting the intake advance angle and exhaust advance angle to increase engine power under the low speed or high speed.