路面激励对车用发动机动平衡特性的影响

Effect of Road Excitation on the Dynamic Balancing Characteristic of Vehicle Engine

为探求路面激励对车用发动机动平衡特性的影响,深入分析路面激励引起不平衡力和力矩变化的原因,结合发动机工作特点、车辆行驶特点以及路面激励特征,推导出考虑路面激励情况下的发动机动平衡参数计算式,运用ADAMS/Car ride、ADAMS/Car和ADAMS/Engine建立四柱试验台整车模型和发动机模型,分别以某等级道路上车速60 km/h、80 km/h和100 km/h时的悬置振动状态为边界条件,计算上述车速各挡位对应的曲轴转速固定基础状态和考虑路面激励的倾覆力矩和曲轴内弯矩,并对两种条件下的计算结果进行对比分析。结果表明:考虑路面激励作用的发动机动平衡相对劣于固定基础状态,且劣化幅度与车速的增加成正比变化,最大劣化幅度可达9.78%;另外,在相同车速条件下,挡位越高,路面激励对发动机动平衡影响越大。

In order to explore the effect of road excitation on the dynamic balancing characteristics of vehicle engine,and to deeply analyze the reasons for imbalance force and moment variation caused by road excitation,the formulas of engine dynamic balancing parameters with consideration of road excitation are deduced by combining the characteristics of engine working,vehicle traveling and road excitation.Four-post test rig whole vehicle model and engine model are built by using ADAMS/Car ride,ADAMS/Car and ADAMS/Engine.The engine mounting vibrations when the vehicle speeds are 60 km/h,80 km/h and 100 km/h respectively on a road of certain level are taken as boundary conditions,the overturning moment and internal bending moment of crankshaft are calculated under fixed-base condition and under road excitation condition at crankshaft speed corresponding to vehicle speed gears,and calculation results under the two different conditions are compared and analyzed.The results indicate that the dynamic balancing of engine taking road excitation into account is inferior to that under fixed-base condition,and the degradation amplitude increases in proportional to the increase of vehicle speed.The maximum degradation amplitude can reach up to 9.78%.Moreover,at the same vehicle speed,the higher the gear is,the greater effect of road excitation on the dynamic balancing of engine will be.