大马力拖拉机牵引作业工况下换挡控制研究

Study on shift control of high-powered tractor in traction operation

采用组合式部分挡位自动变速的变速传动模块,增加了大马力拖拉机持续作业的工作阻力范围。文章针对该变速传动模块中的四速动力换挡模块,以油门开度、模块输出轴转速为换挡参数,提出了在牵引作业工况下避免循环换挡的换挡控制策略,并基于拖拉机纵向动力学方程搭建立了仿真模型。仿真结果表明,在换挡控制策略下,变速传动模块在工作阻力变小时升挡,在工作阻力变大时降挡,同时避免了在特定工作阻力下的循环换挡现象,改善了拖拉机的燃油经济性,同时使得拖拉机能够在较大工作阻力范围内持续作业,提高了拖拉机的生产率。

A combined transmission module with partial automatic gears shifting is adopted to increase the working resistance range of the high-powered tractor so that the tractor can operate continuously. Based on the four speed power-shift module in the transmission module, the throttle opening and the output shaft speed of the module are chosen as the shift parameters, and the shift control strategy avoiding the cyclic shift in the traction operation is proposed. Based on tractor longitudinal dynamics, the simulation model is also established. The simulation results show that based on the proposed shift control strategy, the transmission module shifts up when the working resistance gets down, and shifts down when the working resistance gets up. Moreover, the phenomenon of cyclic shift in specific resistance is eliminated. The strategy improves the fuel economy and the productivity of tractor by continuous operation in a large range of working resistance.