不同转鼓加载阻力下的轻型汽车WLTC油耗差异

对车辆在转鼓上的运行过程进行受力分析,提出通过计算修正后的循环能量需求来对油耗结果进行定量分析的方法。对10辆车分别使用国六标准中规定的两种阻力加载方式--"滑行法"和"计算法"进行WLTC油耗测试,结果显示,修正后的循环能量需求差异比值同车辆综合油耗的差异比值基本一致。比较了不同参数车辆各自采用这两种不同加载方法下的WLTC循环能量需求的差异,结果表明,当车辆空气阻力系数小于0.4时,采用滑行法的油耗结果要小于计算法;而对于空气阻力系数较大的载货汽车或多用途乘用车,两种加载方式下油耗差异较小。两种阻力加载方式下的油耗差异随着车辆空气阻力系数的增大呈下降的趋势。研究结果对WLTC循环的油耗测试中车辆阻力加载方式的选择提供了依据。

Comparison of Light-Duty Vehicle Fuel Consumption Test Results for Different Chassis Dynamometer Resistance Over the WLTC

The resistance setting of chassis dynamometer has a direct impact on the results of vehicle fuel consumption test.The force analysis was conducted during the vehicle operation on a chassis dynamometer and a quantitative analysis method of fuel consumption is carried out by calculating the corrected cycle energy demand.The WLTC fuel consumption tests of 10 vehicles were performed by using two kinds of road-load setting methods in the China VI standard,i.e.the coast-down method and the calculation method.The results show that the percentage difference of the corrected cycle energy demand is basically consistent with that of the fuel consumption.The energy demands over the WLTC of different vehicles with the two road-load setting methods on the chassis dynamometer are compared.The results show that when the air drag coefficient is less than 0.4,the fuel consumption result of coast-down method is less than that of the calculation method,while for trucks or multi-purpose passenger vehicles with a larger air drag coefficient,the difference in fuel consumption between the two methods is smaller.The difference in fuel consumption between the two modes decreases with the increase of vehicle air drag coefficient.The paper provides a basis for the selection of resistance setting methods on chassis dynamometers in fuel consumption tests over the WLTC.