Offline Electro-Hydraulic Clutch Bench Testing Alternatives for a Pre-Transmission Parallel Hybrid Powertrain 2016-01-2225

This paper details the development of a test-bench simulation to characterize the behavior of an electro-hydraulic actuated dry clutch used in a pre-transmission parallel hybrid powertrain architecture of Wayne State University EcoCAR 3.

Engage and disengage systems play a crucial role in a pre-transmission parallel hybrid architecture. The most common device used to meet the purpose of physically connecting internal combustion engine and electric powertrains is a dry clutch. Its own characteristics and capabilities allow its usage for this application. The transition between the pure electric and hybrid modes is dictated by the main control strategy. Therefore, the engaging system will be widely used when switching from charge depleting to charge sustaining mode, and vice versa. In addition, when torque is required from both sources for higher performance, the clutch will be responsible for mechanically connecting both torque sources. Testing this system is significantly helpful prior to implementation in the vehicle. In order to perform bench testing, a motor dynamometer setup has been used and modified at WSU facilities emulating the engine and electric motor of a vehicle. The control strategy includes speed matching, friction plate position, and torque monitoring. The hybrid clutch system has been modeled in Simulink, tested, and validated as a component in the loop with its own soft ECU. Bench testing for this component is also discussed due to the wide range of applications, e.g. clutch-assisted engine start which will be analyzed by the team for future implementation.