Optimizing efficiency and range of electrified vehicles using virtual vehicle development

Authors

S. Yan - IPG Automotive GmbH

Summary

Driving range and efficiency are two of the major influencing factors on current development efforts for electric vehicles. While the focus is obviously on battery and power-train technology, an optimized operation strategy can greatly contribute to achieving range and efficiency goals. Significant negative torque generation by the electric powertrain adds an important degree of freedom to modern brake systems. While braking performance was primarily measured by fast vehicle deceleration and safe handling in the past, the reclaim of kinetic energy becomes more and more important. The operation strategy for regenerative braking (recuperation) not only influences range and efficiency in general. It also requires the engineers to tune the electric driving experience for various powertrain architectures according to the specific OEM’s vehicle DNA and customer usage profile.

This interdisciplinary challenge between brake, chassis and powertrain systems has to be continuously incorporated into the development process and solved by cross-do-main team collaboration and know-how. A full vehicle simulation environment is able to support these activities. Early on, virtual vehicle prototypes can be built up and used in a MIL/SIL environment to evaluate the performance regarding relevant optimization criteria. Further on in the process, component and powertrain prototypes can be included for calibration and testing on HIL test systems.

In an application example different electric powertrain architectures and recuperation strategies are analyzed for energy efficiency and range in several real driving scenarios, also considering general driveability. The results from the MIL testing environment indicate that a careful calibration (especially for rear-wheel drive vehicles) is necessary to ensure the vehicle’s driving stability, but also allow for the highest amount of regenerative braking.