The Application of Thermal Modelling to an Engine and Transmission to Improve Fuel Consumption Following a Cold Start

Automotive manufacturers are under pressure to improve the fuel consumption and emissions figures produced by standard drive cycle tests of their vehicles. Drive cycle tests, such as the New European Drive Cycle (NEDC) start with the engine and transmission cold. The fuel consumption is worse for a cold powertrain than when it is at normal operating temperatures and consequently one way of improving both fuel consumption and emissions is by heating the powertrain as quickly as possible. The PITSTOP (Powertrain Integrated Thermal Systems for Thermodynamically Optimised Performance) project brought together several companies to find ways of reducing the powertrain warm up time. Part of the project was to develop a thermal model of the engine that could both simulate the baseline powertrain and predict the potential improvements of alternative thermal management strategies. The best strategy that was achieved was to transfer heat from the exhaust gases to the coolant, engine oil and the transmission oil in a controlled way. This paper describes the thermal model and how it was used.