| An integrated study of the valve train including all the key factors of design, dynamic motion, lubrication, and friction was performed. This study consists of a computational simulation with experimental verification. The simulation includes an integrated analysis of kinematic synthesis, vibrational motion, and a tribological study of instantaneous friction and lubrication. Experimental data was used to verify the modeling and to acquire the precise input parameters of the model. The experiments and analysis were made for the Cummins L-10 diesel engine over a speed range of 750 rpm to 1500 rpm.; The vibrational analysis includes a multi degree of freedom model with nonlinear stiffness coefficients for each part and a distributed parameter model of the valve spring. The ordinary differential equations derived from valve train parts and the partial differential equation of the valve spring were solved simultaneously by using a new scheme of numerical analysis called "Time Marching Step." The pushrod force obtained from the simulation shows good agreement with measured pushrod force.; A mixed lubrication model of the contact between a cam and a roller follower was developed to investigate the oil film thickness and friction. This model was able to predict slippage of the roller follower through the friction analysis.; Experimental data were gathered on forces, motion, and friction losses in the valve train studied. From these measurements, friction values were determined. |
