发动机气门间隙异常仿真分析研究

研究了柴油发动机气门间隙异常对配气机构动力学性能的影响。对配气机构进行了多质量动力学模型计算,建立了配气机构的多体动力学模型,设置3种不同的气门间隙进行分析。分析结果表明:气门间隙变大会造成气门速度、加速度增大以及气门连接部件的冲击力增大,会使发动机产生异响;气门间隙变大也会使配气机构之间的接触力增大,加速凸轮轴的点蚀磨损,气门发生故障的危险系数增加;相对而言,排气门发生故障的概率远大于进气门。所进行实验的验证结果与模拟分析结果相同,从而证明了仿真模型的有效性;经过实验验证发现:排气门间隙过小将会使气门与活塞头部碰撞,造成活塞头部损坏。

Simulation analysis of engine valve clearance abnormality

The effects of valve clearance abnormality on the engine’s valve mechanism were analyzed.The multi-body dynamics model was used and three different valve clearance were studied in the experiment.The results showed that with the increasing of valve clearance,the valve velocity,acceleration and the contact force of the valve-train were increased,which not only caused abnormal engine noise,but also accelerated pitting wear of camshafts,as a result,high valve clearance would increasing the risk factor of valve failure,and the failure coefficient of exhaust valve is much larger than the inlet valve.The results of simulation analysis were verified by test,which proved the validity of the multi-body dynamics model;a low valve clearance had less destructive effects on the valve-train,but the impact between the valve and the piston head may cause broken.