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为了确定用于纵坡设计的主导车型,选择了几段典型纵坡路段进行了实地速度观测,通过分析轻型客车和货车在纵坡坡度i>3%和i≤3%的上坡路段车辆运行特性,由汽车在坡道上的运动方程推导出功率质量比计算模型,并提出了一套汽车功率质量比计算的试验方法。在实地观测数据的基础上,计算出该路段的功率质量比值,由15%位货车功率质量比得出公路纵坡设计主导车型的功率质量比。结果表明:纵坡坡度对轻型客车上坡行驶车速影响不大;小于3%的纵坡坡度对货车上坡行驶的速度影响很小;陡坡对货车车速影响显著,在临近坡顶处,货车处于一种稳定、匀速的行驶状态;试验路段地区高速公路纵坡设计主导车型的功率质量比为8.0~8.33 kW.t-1;根据汽车功率质量比计算模型和试验方法,确定不同地区、不同公路等级货车功率质量比,由此可以建立最大纵坡坡度、不同纵坡的最大坡长等几何线形设计参数。
In order to determine the dominant vehicle model for longitudinal slope design, several typical longitudinal sections were selected for field velocity observation. By analyzing the vehicle operating characteristics of light passenger vehicles and trucks on uphill sections with longitudinal slope gradient i> 3% and i≤3% , The power quality ratio calculation model is derived from the equation of motion of the car on the ramp and a set of test methods for calculating the power quality ratio of the car is proposed. On the basis of the field observation data, the power quality ratio of the road section is calculated, and the power quality ratio of the dominant model of highway longitudinal slope design is obtained from the power quality ratio of 15% trucks. The results show that: the vertical slope has little effect on the speed of light bus driving uphill; the vertical slope of less than 3% has little effect on the speed of the truck; the steep slope has a significant impact on the speed of the truck; A stable and uniform driving condition; the power quality ratio of the dominant model designed for the longitudinal section of the freeway in the test road section ranged from 8.0 to 8.33 kW.t-1; according to the vehicle power quality ratio calculation model and test method, Grade truck power mass ratio, which can establish the maximum longitudinal gradient, the maximum slope length of the different longitudinal slope geometric parameters such as geometric design.