A Numerical Approach to Thermal Management of Dynamic Driving Cycles

Vehicle thermal protection has become more important than ever in the vehicle development process. Harsher emission standards and improved fuel economy driven by legislation weighs against the driver’s desise for cars with good driving performance. These challenges are driving development towards compact engine layouts with higher specific engine performance. In addition, a tighter packaging of the exhaust system next to the engine is causing higher thermal loads in the engine compartment. The major aim of thermal protection is to ensure that all components inside the vehicle stay well below their temperature limits.

Digital methods are considered to be the key elements for speeding up the development process and reducing cost. These methods involve transient full Vehicle Thermal Management (VTM) simulations to predict dynamic vehicle heat-up during driving cycles such as trailer towing uphill drive or the customized uphill drive, and also city driving cycles were the thermal loads cycle in ways that are very difficult to predict without complete system simulations. Within these driving cycles thermal control system events occur which have to be taken into account in the computational approach.

In this presentation an overview is given of new modeling and simulation methods developed with the help of CD-adapco’s Engineering Services group, including development of process specific Custom Tools, and how these simulation methods are utilized in the digital development process at Mercedes Benz. A transient full VTM simulation of a dynamic driving cycle is demonstrated and compared with test results. Methods of accelerating the turn-around times are shown.

Mario Disch
Speaker Company: 
Daimler AG