An automated method for obtaining engine fuel consumption and efficiency models from road test data

Engine efficiency maps are a fundamental tool for estimating fuel consumption and CO2 emissions during vehicle driving, both for simulation analysis and for optimisation of vehicle control. They usually require extensive experimental work on engine test bench, in laboratory, with significant effort in terms of time and money. In this paper, a technique for mapping engine efficiency as a function of torque and engine speed is presented. The procedure includes on-road tests in release mode to estimate the longitudinal vehicle model, and the use of fuel mass rate sensors on board. The efficiency maps are then obtained via regression techniques. In this paper, the results obtained starting from on-road tests are presented, and an application to estimate fuel consumption in a hybridised car is discussed.