轻型车与重型车高速公路比功率分布特征研究

在机动车油耗排放测算中，机动车比功率已经成为一个重要的参数.目前主要的油耗排放模型均采用比功率分布（VSP分布）结合油耗排放率的方法来进行微观油耗排放测算.为了将交通流状态与机动车油耗排放相结合，之前的研究已经对轻型车在城市道路上的行程速度与VSP分布之间的关系进行分析.本文将通过实例研究轻型车和重型车在高速公路上的VSP 分布特征.首先，采集轻型车和重型车在高速公路上实际运行的数据并以此建立轻型车和重型车的VSP分布；其次，对两种车型在高速公路上的VSP分布特征进行比较分析；最后，利用MOVES中提取到的油耗率，分析使用轻型车的VSP分布来进行重型车油耗测算所产生的误差.

Characteristics of VSP Distributions of Light-duty and Heavy-duty Vehicles on Freeway

Vehicle specific power (VSP) has become an essential parameter in the measurements of vehicle fuel consumption and emissions. In the existing fuel consumption and emission models, the micro-scale fuel consumption and emission estimation is conducted by a combination of VSP distributions and fuel consumption or emissions rates. To associate the traffic performance with fuel consumption and emissions, the relationship between VSP distributions of light-duty vehicles (LDVs) and the average travel speed on the urban road was constructed in earlier studies. This paper is intended to study characteristics of VSP distributions for light-duty and heavy-duty vehicles on the freeway using a case study. First, the field data are collected for a LDV and a HDV on the freeway, by which the VSP distributions are developed. Then, a comparison of VSP distributions for the LDV and HDV is conducted. Finally, an analysis is conducted to determine the errors in estimating the HDV fuel consumption by using the VSP distributions of the LDV and the fuel consumption rates in MOVES.