Modeling and Validation of Traveling Resistance for Heavy Trucks 2001-01-0555
Low fuel consumption is very important for a heavy truck. Doing measurements of fuel consumption in a real vehicle is though complicated and very time-consuming. The main problem is that measurements are not repeatable. By use of computer simulations an ideal but repeatable result of fuel consumption and emissions can be created and differences between vehicles can be studied.
A computer program to simulate fuel consumption and emissions for heavy trucks in long haulage has been created, using the object-oriented software DYMOLA. It has a longitudinal vehicle model and an engine model based on steady-state measurements.
In this paper the validation of external forces, like air resistance and rolling resistance, is presented. This has been achieved by equipping a heavy truck with strain gauges to measure the torque on the propeller shaft. Several tests have been run at various constant speeds on flat road.
After modification of the powertrain modules, mainly the rolling resistance, a difference between simulations and measurements of only 0.015 Nm at all speeds has been reached. The vehicle model should therefore have all prerequisites to make good calculations of fuel consumption.