发动机制动工况下汽车制动器摩擦性能分析

Analysis of Automotive Brake Friction Performance in Engine Braking

建立了基于恒速制动车辆纵向力平衡方程、制动器耗散功率及其温度变化微分方程、管路压力调节等子模型的恒速长下坡汽车制动器摩擦性能分析系统。以两轴中型汽车为例,对前后制动器在不同挡位发动机制动时的温度、制动副摩擦因数、制动力分配及管路压力变化进行了计算。结果表明,在不影响车速情况下,合理使用各挡发动机制动可改善汽车前、后制动器热负荷,减小或避免制动摩擦力矩热衰退,保证汽车下长坡安全行驶。

The downhill braking performance analysis system with constant vehicle velocity is established based on the vehicle＇s longitudinal force balance equation, brakes dissipation power equation and their temperature differential equations, line pressure control model and so on. Then temperature, friction factor of braking pair, braking force distribution and line pressure variation of the front/rear brakes are calculated for a medium duty vehicle with two axles during engine braking at different gears. The results indicate that, under the prerequisite of not affecting vehicle speed, using engine braking appropriately at different gears can improve thermal load of the front and rear brake, reduce or avoid heat fade of braking friction moment, ensure safe downhill driving of the vehicle.