A method for calculating Heavy-Duty Trucks energy and fuel consumption with the use of correlation formulas derived from VECTO simulations 2019-01-1278
The Vehicle Energy Consumption calculation Tool (VECTO) is used in Europe for calculating standardised energy consumption and CO2 emissions from Heavy-Duty Vehicles (HDVs) for certification purposes. The tool requires detailed vehicle technical specifications and a series of component efficiency maps. In the context of quantifying HDV CO2 emissions, the Joint Research Centre (JRC) of the European Commission collected simulation data about the 2016 vehicle fleet. The simulation data were initially normalised to compensate for differences and issues in the quality of the input data used to run the simulations. Secondly, the data received were used to understand the factors contributing to the energy consumption. Correlation formulas were produced to calculate individual energy loss contributions (air drag, rolling resistance, axle and gearbox losses) over the regional delivery and long-haul cycles, given few input parameters such as vehicle characteristics and average component efficiencies. Default values and meaningful ranges of variation of these parameters were derived from the fleet data and are reported in the paper. The importance of air drag and rolling resistance losses is presented, which for the cycles considered account for about 75% of the total energy consumption. Finally, based on the correlation formulas to calculate some of the individual energy losses, a method is presented that calculates the final energy consumption and CO2 emissions for all the regulated HDV classes that does not rely on the use of VECTO. A scenario regarding the possible future evolution of the fleet CO2 emissions based on the current understanding of the technological progress was formulated and analysed.