换挡过程两换挡执行元件充放油交替方法研究

Research on Timing Method of Two Shifting Actuators Filling and Draining Hydraulic Oil During Shifting

液力机械自动变速器(AT)换挡过程中两个换挡执行元件充放油交替过程时序不当会造成动力中断或重叠过多(俗称"挂双挡),并引起功率损失、换挡冲击及加剧换挡执行元件磨损。以艾里森大功率自动变速器(HD4070PR自动变速器)为研究对象,利用拉格朗日方程建立换挡过程的动力学方程,依据所建立的方程分析升降挡过程中两换挡执行元件充放油交替方法,并通过自行开发的电控系统进行了实车试验验证。研究结果表明:对于升挡过程通过合理的动力搭接既可以实现无动力中断换挡,又可以减小换挡冲击;对于降挡过程不可避免出现动力中断,只能尽可能地降低动力损失。

The shifting process of automatic transmission is an alternating process of two actuators filling and draining the hydraulic oil. The improper oil filling and draining of two shifting actuators may cause power interruption or too much overlap, power lose, impact of shifting and aggravated wear of shift actua- tor. Lagrange equation is used to establish the dynamic equation of the shifting process by taking Allison automatic transmission （HD4070PR） as the study subject. The timing method of two shifting actuators filling and draining hydraulic oil during shifting process is analyzed on the basis of the equation, and veri- fied by real vehicle test. The research results show that, for the upshifting process, the power shifting can be realized, and the impact of shifting can be reduced through the rational power lap;and for the down- shift process, since the emergence of power interruption is inevitable, only the loss of the power should be reduced as far as possible.