Powertrain Mount Load Mitigation on Hybrid and Electric Vehicles 2011-01-0949
The development and validation of an electric vehicle presents numerous issues that are not normally encountered during the development of a traditional internal combustion powered vehicle. Many of the issues that are encountered involve components that are common to both electric and internal combustion vehicles but are utilized in new or unique ways that may present challenges during the development process. The integration of the electric motors, power supply, batteries, and associated content into a traditional vehicle can bring new and challenging issues to light.
This paper discusses the solution for an issue that arose during the testing and development of the chassis and powertrain hardware of an electric vehicle. In particular, the large rotational inertia of the electric drive motor presented significant challenges when it was accelerated by forces that were external to the drive unit. In this instance the acceleration combined with the large inertia of the motor caused excessive loads to be transferred to the powertrain mount system and caused a failure of the mount system.
As in any vehicle under development, it was highly desirable to use low mass hardware whenever possible. As such, an innovative control system was developed to monitor the vehicle systems for instances in which excessive rotational acceleration of the electric motor was possible. When the acceleration and corresponding mount loads were predicted to cause damage to the mounting hardware, the control system took preemptive action to dissipate the excessive energy. The newly developed control system was able to reduce the loading in the powertrain mount system significantly and allowed for the use of low mass hardware in the vehicle.