Simulation Analysis For Valve System Of140Engine

The valve system controls the air intake and exhaust of the engine, so it has great influence to the engine performance. Along with the technology development of the engine, the dynamic analysis of valve system catches more attention gradually and more deep study has been performed. The kinetic modeling analysis and dynamic modeling analysis of this valve system have been widely applied to the valve mechanism design and research.Technology development of the computer promotes the widely application of simulation software. For example, EXCITE Timing Drive, developed by AVL Company in Austria, is special software widely used in engine field. This software can be used for cam profile design and optimization; it can also be used for valve timing analysis, driving system dynamic calculation, chain belt transmission system dynamic calculation, gear transmission and dynamic calculation.Through using the software Excite Timing Drive, this paper builds a model of the valve system and makes the simulation, designs the cam profile, analyzes the kinematic and dynamic performance of valve system, calculates the valve seating force, bearing force, spring force, and studies the valve bouncing as well as its influence. Based on the simulation results, the writer adjusts the design parameters, such as optimizing the cam profile, designing the valve spring as well as adjusting its parameters. Thus, all the results are more reasonable. In this way, it has achieved the optimum design data for valve system. The results indicate as follows:1、The kinetic model simulation result shows surplus of the valve spring forces is safe at all cam position. Both intake and exhaust cam profile have hollow flank. The radial distance is enough between cam nose and camshaft bearing. The clearance between the valve and piston is enough while running.2、The dynamic model simulation result indicates both cam and follower have very good contact performance at all engine speed condition. No loss of contact condition is happened. Contact force is well below the material limit of camshaft. There is no valve bouncing while valve seating. The valve seating force and velocity for both valves are reasonable. Normal wear on valve seat is predicted. No touch of coils at all speed range.3、Three air intake cam proposals, such as standard solution, short solution and long solution, have been simulated and analyzed. The standard solution has been applied to the engine test to verify the reliability of the analysis results.