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利用几何法和函数法对4125柴油机配气机构的凸轮型线进行设计,通过计算和比较两种凸轮型线下挺柱运动的位移、速度和加速度曲线得出:几何凸轮型线的换气时面值大,有利于提高发动机的充量系数,但在气门开启和关闭的瞬间以及速度的绝对值达到最大时,挺柱的加速度均发生突变,因此,采用几何凸轮的配气机构将产生较大的振动和噪声;函数凸轮挺柱的加速度连续光滑变化,在整个工作阶段,无加速突变,并且其最大加速度的绝对值约为几何凸轮挺柱最大加速度绝对值的1/2,所以,采用函数凸轮的配气机构工作平稳,产生的振动和噪声小,但对进气充量有不利影响,可通过增大气门直径或采用多气门等工程上常用的措施加以改善。
The geometrical method and function method are used to design the cam profiles of 4125 diesel engine gas distribution mechanism. By calculating and comparing the displacements, velocities and acceleration curves of the bottom plungers of the two cam profiles, The larger face value helps to improve the engine’s charge coefficient, but the tappet accelerates abruptly at the moment when the valve is opened and closed, and the absolute value of the velocity changes. Therefore, a valve with a geometric cam will generate a larger The acceleration of the function cam tap continuously and smoothly changes without acceleration mutation in the whole work stage and the absolute value of the maximum acceleration is about 1/2 of the absolute value of the maximum acceleration of the geometry cam tappet. Cam valve body work smoothly, the vibration and noise generated, but the intake charge has an adverse effect, by increasing the valve diameter or multi-valve and other engineering commonly used measures to be improved.