VEHICLE CHARACTERIZATION AND FUEL CONSUMPTION PREDICTION USING MAPS AND POWER DEMAND MODELS

A sample of 177 currently used Australian light duty vehicles have been dynamometer tested and averaged vehicle maps of fuel consumption and emissions are presented. These maps show emission rates and fuel consumption as a function of vehicle velocity and acceleration. The use of vehicle maps as a diagnostic tool to characterise vehicle behaviour is also demonstrated. A two–parameter vehicle power demand model is developed which predicts road (or dynamometer) vehicle fuel consumption, hydrocarbon and oxides of nitrogen emission rates for any desired velocity profile. For trips of moderate length (> 10 km) the fuel usage estimates are correct to within 2 per cent. Short trip estimates (I km or less) are correct to within 9 per cent. A power demand model correction matrix is presented which is used to predict fuel usage for short trips (100m or less). This matrix adjusts the basic power demand model for vehicle inefficiencies at low speed due to gear and automatic transmission losses.