Dynamic Analysis Of Valve Train In Diesel Engine

Valve train is one of the most important mechanisms in internal combustion engine. The performance of the valve train affects the economic, power, and wear performance of the engine. The dynamic analysis of the valve train is one of the most important research directions in the field of internal combustion engine. While the engine performance requirements continue to rise, valve train dynamic analysis is of great significance.A diesel engine valve train is modeled in the paper. Firstly, the accessories, including tappet, pushrod, rocker, intake valve, exhaust valve, intake valve plate, exhaust valve plate, and valve block etc., are built and assembled in Pro/Engineer. The mass, stiffness, and damping of these parts are calculated. In this paper, the dynamic model of the engine valve train is built up and analyzed by using the software AVL-Excite Timing Drive.According to the dynamic model of valve train, when the engine speed is 1000rpm and the clearance of intake valve is 0.72mm or 0.62mm, a series of dynamic analysis on the valve train is performed. Displacement, velocity, and acceleration of the intake valve and exhaust valve, contact force between the tappet and pushrod, contact force between the valve and valve plate, and mass displacement of the spring center are obtained. Compared to the test data, it can be noticed that the simulation curves are coincident and the forces in the valve train are less than the allowable limitation. The results show that the simulation of the model is feasible. Comparing the curves of different clearance of intake valve, it can be seen that the size of valve clearance have a great effect on the acceleration of the valve during open and close periods, and the contact force between the valve and valve plate.