Total System Simulation of Modern Powertrain Concepts – From an Industrial Perspective

Ruediger  Steiner, Daimler AG

Due to ecological and political reasons, more and more the automotive markets are controlled by CO2! The green house effect as result from the combustion of fossil fuels is increasingly discussed and of social concern. In addition to the fuel prices, legislative conditions like CO2-based taxes, grants and ZEV driving zones are the driving forces for this development and become an increasing importance all over the world. As one result alternative drivetrain concepts are about to enter the markets as one of the mainstream products. All OEMs present their ideas of how the car of the near future could look like, as seen at the auto shows in Frankfurt, Detroit, Los Angeles and Geneva. This “revolution in mobility” implies big challenges for the engineers of all car makers. There is a high demand on efficient powertrains which should be on market already today! Beside the CO2-targets, emissions, comfort in addition with affordable cost must be considered in order to come up with a reasonable overall concept. The technical solutions include an enormous high degree of possibility.

Without simulation work the complexity and variety of vehicles, engines and alternative drive train concepts cannot be controlled. In order to evaluate at an early concept phase (front-loading) computational analysis for different alternative drive train concepts are needed. That means the prediction of main system characteristics as fuel consumption and driving performance for different kinds of driving cycles. Additionally, simulation is needed to optimize total system behaviour in order to support hardware development to fulfil the technical specifications. And all must be done under consideration of essential boundary conditions including not only fuel efficiency but also primarily safety, emissions, comfort and costs. All this implies the request of powerful simulation tools with a high degree of fidelity and low computational costs. Additionally, a close link between simulation and experiment is needed. As an example, the following figure depicts the powertrain sub-system engine and aftertreatment. Based on offline simulations efficient closed-loop control systems can be derived.

The objective of this presentation is to discuss the following topics from an industrial point of view
– Current challenges for the development of modern drivetrain concepts
– Where can simulation help? Which approaches are available?
– Tool chain at Daimler: Model description and presentation by using a practical example
– What needs to be done in the future?