VEHICLE CHARACTERISATION AND ON-ROAD FUEL PREDICTION USING MAPS AND POWER DEMAND MODELS

One hundred and seventy seven in-use Australian light duty vehicles have been tested and fleet averaged vehicle maps are presented. These maps show the vehicles' emission rates and fuel consumption as a function of vehicle velocity and acceleration. The use of vehicle maps as a diagnostic tool to characterize vehicle behaviour is also demonstrated. A two-parameter vehicle power demand model is developed which gives on-road (or on-dynamometer) vehicle fuel usage, hydrocarbon and oxides of nitrogen emission rate predictions 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 (1 km or less) are correct to within 9 per cent. A power demand model correction matrix is presented which is used to give fuel usage predictions for short trips (100 M or less). This matrix corrects the basic power demand model for the vehicle energy lows at low speed due to gear and automatic transmission inefficiencies. For the abstract of the covering entry see TRIS no. 378221. (Author/TRRL)