高速公路连续下坡路段货车制动毂温升模型修正研究

Study on Temperature Rise Model of Truck Brake Hubs on Continuous Downhill Section of Expressway

为使下坡路段货车制动毂温升模型更加符合货车制动毂温度变化规律,提高连续长大下坡路段的安全性,从而更好地指导连续下坡路线纵断面设计,基于连续下坡路段货车制动毂温升机理,通过对长下坡路段主导车型的行车动力学以及热力学分析,对同济大学制动毂温升模型进行修正,在同济模型以三轴载重货车为主导车型的基础上,采用与规范和实际中更符合的东风六轴铰接列车为主导车型,并在发动机辅助制动工况条件下,利用雅西高速3处连续长大下坡路段对该修正后的模型进行了实车验证。结果表明:修正温升模型得到的温升曲线与实测温升曲线更贴合,且修正模型预测的温度与实测温度间的差异随坡长的增加逐步减小,平均差异为16.5℃,低于修正前模型温度与实测温度的平均差异41.5℃。制动毂在3段下坡的预测温度与实测温度间的平均温差分别为21,12.4,21.4℃,均未超过25℃,且温度变化趋势基本一致,说明修正后的温升预测模型精度更高,货车制动毂温升修正模型能更好地预测连续下坡路段的货车制动毂温升状况。

In order to make the temperature rise model of truck brake hub more in line with the rule of the temperature change of truck brake hub, improve the safety of trucks on continuously long downhill section, and better guide the design of the longitudinal section of continuous downhill road, based on the temperature rise mechanism of truck brake hub on continuous downhill road, by analyzing the driving dynamics and thermodynamics of the leading vehicle types on the long downhill section, the temperature rise model of the brake hub of Tongji University is revised. On the basis of Tongji model which takes 3-axle truck as the leading vehicle type, the improved model adopts Dongfeng 6-axle articulated train as the leading vehicle type, which is more consistent with the reality. Under the engine-assisted braking conditions, the revised model is verified by real vehicles using 3 continuous long downhill sections of Ya’an-Xichang expressway. The result shows that(1) the temperature rise curve of the modified model is more close to the measured temperature rise curve, the difference between the temperature predicted by the modified model and the measured temperature gradually decreases with the increase of the slope length, and the average difference is 16.5 ℃, which is lower than the average difference between the temperature obtained by the un-modified model and the measured temperature(41.5 ℃);(2) the average temperature difference between the predicted temperature and the measured temperature of the brake hub on the 3 downhill slope sections is 21, 12.4, and 21.4 ℃ respectively, which do not exceed 25 ℃, and the temperature change trend is basically the same, indicating that the modified temperature rise prediction model is more accurate, which can better predict the temperature rise of the truck brake hub on the continuous downhill section.