发动机起动减压机构原理研究及计算实现

The Research on the Principle of Engine Starting Pressure-reducing Mechanism and Computing Realization

本文首先阐述了当今摩托车在起动特性上的发展趋势,提出了设计起动减压机构的必要性。然后阐述了起动减压机构的工作原理,给出了起动减压机构的设计要点:主要包含减压相位角、减压凸台高度、减压工作转速等内容。接着详细推导了三种起动减压机构(包括拉簧蹄块式减压阀、扭簧离心式减压阀,停机式减压阀等)各参数间的运动学关系,然后引入弹簧载荷、离心快质量,通过动力学方程,求得所能起作用的转速,同时指出可通过改变几何参数或弹簧载荷、离心块质量及质心位置,可优化减压机构的工作转速。接着指出了各种减压机构的优缺点及适用的场合。最后给出了一款发动机减压机构的计算实例,比较了不带减压阀与不带减压阀起动压力的差别,证明了减压阀设计流程及计算结果的准确性。

This article firstly expounds the current development trend of the starting characteristics of motorcycles,and puts forward the necessity of designing the starting pressure reducing mechanism.It explains the working principle of the starting pressure reducing mechanism and the key design points of the starting pressure reducing mechanism are given:It mainly includes the designs of pressure reducing phase angle,the height of the pressure reducing boss,and the working speed of the pressure reducing.Then it deduces the kinematics relationship among the parameters of the three starting pressure reducing mechanisms(including tension spring shoe type pressure reducing valve,torsion spring centrifugal pressure reducing valve,and stop type pressure reducing valve etc.).And then it indicates that the effective working speed can be get through the dynamic equation.And working speed can be optimized through changing the geometric parameters or spring load,the mass of the centrifugal block and the position of the center of mass.Then it points out the advantages and disadvantages of various press mechanisms and applicable occasions.Finally,a calculation example of an engine pressure reducing mechanism is given.It compares the difference between the starting pressures without pressure reducing valve and with pressure reducing valve,and proves the accuracy of the pressure reducing valve design process and calculation results.