Valve Triain Dynamic Analysis Of Train 4-Valve Gasoline Engine With Variable Valve Dissimilitude Lift

The role of valve train is to open and close the valve in sequence according to the specified order,so that the combustible gas enter the cylinder,the exhaust gas discharge cylinder.The double intake cam profile and double intake valve opening and closing time of the conventional valve train are all constant,it will offset the swirl effect of the gas flowing into the cylinder,which is not conducive to the combustion of the gas.In view of this situation,a new 4-valve gasoline engine with variable valve train is analyzed in this paper,the specific research content is as follows:(1)The composition and working principle of the dissimilitude lift device in the variable valve train of the new 4-valve gasoline engine is described.Different simulation models of dissimilitude angles are established and imported into the fluid analysis module CFX in the Workbench to simulate the effects of dissimilitude angles on the steady flow characteristics in the cylinder.(2)In order to get a better steady flow characteristics,optimize the matching of the dissimilitude angle,inlet valve seat diameter,inlet pressure and inlet end temperature that affect the steady flow characteristics by means of orthogonal test.The simulation model is established according to the optimized parameters,and the influence of the interaction between them on the steady flow characteristics of the gas in the cylinder is analyzed.(3)The dynamic models of dissimilitude lift device is established to get the dynamic equations.Through modal analysis,to find the natural frequency of the dissimilitude lift device.A static analysis of the meshing gears and bearings at the camshaft of the device is performed to obtain their stiffness and damping.Solving the dynamical equations using the4 th order Runge-Kutta formula to find the radial,axial and torsional vibrations of the device under dynamic excitation.(4)A multiple degree of freedom dynamic model is established for the valve train.The dynamic differential equations are solved by MATLAB to get the intake valve movement law.The multiple body system dynamics model for a new type of variable valve train and a traditional valve train are established in ADAMS to get the kinematic and dynamic results.Comparing the motion curves of the multiple degree of freedom dynamic model and the valve train to validate the correctness of the multiple degree of freedom dynamic model.Through the analysis of the dynamics of the valve train,it is verified whether the dynamic performance of the valve train meets the requirements.