在对车辆制动过程进行力学分析和机械自动变速重型车辆降挡和不降挡两种制动控制策略的比较基础上，提出了在不降挡的前提下，当发动机辅助制动力矩影响行驶稳定性时分离离合器;当车速降低到发动机辅助制动力矩不影响行驶稳定性时接合离合器的控制策略。并对制动过程中分离离合器后是否再次接合离合器这2种情况下制动时的制动减速度、制动时间和制动距离进行比较分析。分析表明当发动机辅助制动力矩不影响行驶稳定性时，接合离合器可明显减少制动时间和制动距离。

According to kinetic analysis, we put forward a braking control strategy under the down shift condition. When auxiliary engine brake torque affects the stability of vehicle, it should disconnect the clutch; and when auxiliary engine brake torque doesn’t affect the stability of vehicle, it should jointing the clutch. The speed acceleration, the braking time, and the braking distance are analyzed in while the clutch and joint the clutch are disconnect. The analysis indicates that when auxiliary engine brake torque doesn’t affect the stability of vehicle, jointing the clutch can reduce the braking time and distance obviously.

国家高技术研究发展计划(863计划)资助项目(2006AA110114)