工程车辆动态换挡规律研究

Study on Dynamic Shift Schedule of Construction Vehicle

工程车辆自动换挡通常模仿汽车换挡规律而采用2参数或者3参数自动换挡技术,也有根据工程车辆的特点而提出以提高液力变矩器的效率为目的的4参数自动换挡策略,然而这些都是静态的换挡规律.在汽车"动态3参数换挡规律"基础上,提出了工程车辆"工程车辆动态换挡规律"(车速、加速度、油门开度、油泵压力),建立了传动系统及车辆各主要部分模型,在换挡时考虑工作油泵压力的变化和道路坡度角对加速度的影响,推导出最佳换挡点与动态参数的关系,并应用解析法对最佳换挡点进行求解,最后进行了试验验证.结果表明,动态4参数自动换挡规律更符合工程车辆的实际工作情况,在兼顾燃油经济性的同时能最大限度地提高车辆的动力性,并且换挡冲击度很小.

The typical shift schedule of construction vehicle was controlled by two-parameter or three- parameter, even the better four-parameter, which parameters were rotation speeds of impeller and turbine, throttle position, pressure of oil pump. However, all of those shift schedules ware static. To express dynamically the multi-variable, parameters time-varied system of construction vehicle, a dynamic shift schedule with four parameter was presented, based on dynamic three-parameter, which parameters were vehicle speed, vehicle acceleration, throttle position and pressure of oil pump. The power train of ZLSOE loader wheel,an example of construction vehicle, was modeled and expressed with mathematic model, then the relation between the best shift point and the four-parameter dynamic shift schedule was deduced, and an analytical method for solving the best shift point was presented. The shift schedule of construction vehicle with dynamic four-parameters is proven to be superior to the static shift schedule in both dynamic performance and fuel economy by the test, and improves the shift quality.