The Research Of The Gasoline Engine Cam Profile And Valve Timing

China’s automobile industry has developed rapidly, increasing car ownership, car While providing convenience to our lives, also brought many problems:urban traffic congestion, environmental pollution, rising gasoline prices. The Government has taken many measures to solve these problems; application of advanced technology to improve the performance of the car is a positive and effective way.The valve train is one of the core of the engine, its performance directly affects the engine of the economy, power and emissions performance, as well as the vehicle’s comfort. Passenger car gasoline engine valve train is a high-speed cam mechanism, the contact position of the deputy campaign dynamics situation is more complex, it is more difficult to carry out precise calculations and design using traditional methods, computer-aided design methods of the valve train, the state-of-the-art technology in the field of research through modeling analysis to solve complex dynamic problems.Firstly establish the performance of the whole model, optimized cam profile and valve timing. The working principle of the analog VVT through orthogonal Selection, combined with practical experience, were selected under different speed and load valve timing to optimize the valve overlap angle, to improve the volumetric efficiency of the engine, the engine in the whole performance within the range of operating conditions are improved. Performance comparison can be seen to have good balance, optimized cam profile and valve timing, high-speed performance has improved low speed performance also improved, further improvements for the engine provides a reference design.Secondly, the application of AVL Excite software creates Engine Valve focus on the dynamics of multi-quality model, a dynamic simulation. In order to achieve the best optimization of the fullness coefficient from the valve velocity, acceleration, cam and tappet hydraulic lubricating effect and contact stress, whether the valve for optimized cam profile, the of polynomial cam and dynamic correction method, spring circle the valve seated anti-hop Analysis of the dynamic performance of the cam profile. Analysis found that high-order polynomial cam after dynamic optimization, has a good dynamic performance, fullness coefficient are better.Finally, verify that the valve train engine bench improved design on engine performance. Experimental verification by the external characteristics of the cam profile and valve timing to enhance engine performance and reduce emissions. Through the valve exercise test to verify the valve train has a good kinematic and dynamic performance. VVT phase selection test to verify the reasonableness of the valve timing. Tests show that the optimization design is reasonable, to achieve the desired purpose.