电动液压助力转向系统的节能优化研究

夏雨　张涌　吴海啸　姜朋昌

摘要：针对某型纯电动商用汽车的EHPS，在传统常流式EHPS基础上提出一种新型的常压式EHPS系统。这种系统在传统常流式 EHPS 系统的基础上加装了蓄能器和电磁阀等结构，取代了电机和液压泵的持续工作状态，使系统既能满足转向助力的需求，又能减轻能量的耗损，实现系统的节能优化。根据系统性能对其关键部件进行合理的选型和计算;基于助力需求选择合适的助力特性曲线形式，并在 MATLAB 曲线拟合工具箱中进行基于车速系数的助力特性的曲线拟合;根据助力特性确立系统控制的方法;在MATLAB/simulink 软件中对常压式EHPS进行建模，对系统的助力响应、控制性能和助力跟随性进行仿真分析，并对能耗进行计算。仿真得到的结果表明，这种常压式 EHPS 能够达到转向助力性和节能性的双重要求。

关键词：常压式 EHPS;助力特性;建模与仿真

中图分类号：U463.4文献标识码：A文章编号：1006-8023（2019）03-0093-07

Study on Energy Saving Optimization of Electric Hydraulic

Power Steering System

XIA Yu， ZHANG Yong*， WU Haixiao， JIANG Pengchang

（College of Automobile and Traffic Engineering， Nanjing Forestry University， Nanjing 210037）

Abstract：For EHPS of a pure electric commercial vehicle， a constant pressure type EHPS has been proposed based on the constant flow type EHPS. This system has been installed an accumulator and solenoid valve on the basis of the traditional constant flow type EHPS， which replaces the continuous working state of the motor and hydraulic pump. This system can not only meet the needs of steering power， but also reduce energy consumption and realize energy-saving optimization of the system. According to the system performance， the key components have been selected and calculated reasonably; choose the appropriate assist characteristic curve form based on the assist demand， and perform curve fitting of assist characteristic based on the vehicle speed coefficient in MATLAB curve fitting toolbox; the method of system control has been established according to the assist characteristic; the constant pressure type EHPS has been modeled in MATLAB/simulink software， and the systems assist response， control performance and power-following performance have been simulated and analyzed， and the energy consumption has also been calculated. The simulation results show that the constant pressure type EHPS can meet the dual requirements of steering assist and energy saving.

Keywords：Constant pressure type EHPS; assist characteristic; modeling and simulation

0引言

轉向系统对车辆的性能影响十分显著，对该系统的研究和改进会提高系统的整体性能。助力转向系统已有多种发展较好的类型，从前汽车上较多采用的是机械液压助力转向系统（Hydraulic Power Steering System，HPS）。随着汽车电子技术的快速发展，电动助力转向系统（Electric Power Steering System，EPS）和电动液压助力转向系统（Electric Hydraulic Power Steering System，EHPS）技术也迅速兴起，在现在许多新能源的纯电动商用车上都能够加以应用。EHPS 保留了 HPS 工作的平顺性和较大的转向助力，同时兼顾了 EPS 的转向轻便性，在中、重型车辆上的应用前景较为乐观。本文对EHPS 系统进行节能优化研究，使优化后的常压式 EHPS 系统既能满足转向助力的要求，又能在一定工况下降低系统的功耗损失，完成节能减排的技术革新，使EHPS 在新能源汽车尤其是纯电动商用车上有比较良好的发展前途。……