旁通比例阀对ECHPS可变助力特性的影响

Influences of Bypass Proportional Valve on the Variable Assist Characteristic of the ECHPS System

为了获得商用车理想的可变助力特性,将执行元件比例阀更好地匹配到ECHPS系统中,有必要研究比例阀结构设计参数对ECHPS可变助力特性的影响规律.在建立了转阀阀口通流面积与转阀主要结构设计参数之间的数学模型的基础上,分析了有、无前置稳压阀式电液比例阀进出口压差变化以及带前置稳压阀的3种比例阀阀口形状对系统可变助力特性的影响.仿真结果表明:出于驾驶安全考虑,采用带前置稳压阀的比例阀较理想.具有梯形和L形阀口的比例阀,在不同车速下驾驶员手力变化明显;高速时,所需驾驶员手力较大,路感较好,比较符合商用车理想助力特性曲线的需求.

In order to obtain ideal variable assist characteristic, let proportional valve match to ECHPS system better, it is necessary to research the influence between structure design parameters of proportional valve and variable assist characteristic of ECHPS system. First, the mathematical model between the flow area of the rotary valve and the configurable design parameters is built, on basis of which analyzing the influence of differential pressure changing between inlet and outlet of electro hydraulic proportional valve which with or without constant pressure valve and three different shape of proportional valve which with constant pressure valve to the variable assist characteristic of ECHPS. The simulation results show that proportional valve with a front stabilizing valve is ideal considering safety driving. To valve proportional valve having a trapezoidal shape and L driv the required drivers hand is bigger and has vehicle ideal power characteristic curve. er hand changes evidently better road feeling, which at different speed; at high speed, satisfied the demand of commercial