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As the key parameters, stiffness and damping coefficient significantly influence on dynamic simulation result, which is the mean method of valve train design. This research aims to investigate the relation between landing velocity (vL), contact duration (Δt), contact force (FN), friction force (FK), loss of valve kinetic energy (ΔWV) on the landing impact between valve and seat insert. Tests were carried out on Over-Head-Cam Valve-train (OHC). Firstly, valve and seat insert contact stiffness in static state was measured, nonlinear increasing of stiffness was observed, because of contact area changing with load. Secondly, valve and seat dynamic impact tests were carried out in different landing velocities. Based on valve contact model, contact force (FN), friction force (FK) and sliding distance (SL) were got by test data. As the result, contact stiffness and damping coefficient in dynamic state were analyzed.

In order to analyze the fatigue life and wear loss of valve seat, a simplified approach was developed to predict fatigue life and wear loss, and a test was conducted to testify the prediction in this paper. Aimed at revealing the effect of mechanical load and thermal load on the fatigue life and wear loss of the valve seat at different camshaft speeds, the ABAQUS software and the experimental data obtained from the valve train test bed were used to predict the fatigue life, which was based on the energy method. The mechanical stress, thermal stress, temperature distribution depending on material properties, and thermal-mechanical coupling stress at different camshaft speeds have been considered in the finite element method simulation. Through analyzing finite element analysis model of valve seat and S-N curve, the fatigue life and wear loss could be both obtained.