Development of a test rig to evaluate the performance of Front-End Accessory Drive systems

The increased adoption of downsized engines along with higher electrical demand is generating a challenge to the Front-End Accessory Drive (FEAD) system functioning and validation. One alternative to speed up the validation of potential design solutions is the in-vehicle experimental tests approach. Nevertheless, experimental data collection during in-vehicle FEAD evaluation imposes some challenges due to, for instance, packaging space constraints and sample rate required to capture the dynamic events during vehicle operation, among others. In order to overcome this limitation, the objective of this research is focused in the development of a customized test rig that emulates FEAD layout of an actual automobile in a simulated operating condition. This equipment could contribute in research studies focusing in critical performance parameters, allowing complete data acquisition and evaluation of potential design trade-offs that could maximize overall performance of the system, as the test rig could also allow the study of the impact of different layouts or operational configurations in the overall system efficiency. Therefore, the test rig design intent is to have a configurable layout that can be fully adjusted and instrumented. It will enable data acquisition and analysis of relevant variables such as motoring and resistive torques, hub loads, belt span vibration levels, among others. Specially those variables that are limited due to packaging constraints during invehicle assessment could be more easily monitored in test rig setup. Moreover, the test rig layout could be adapted to test different types of alternator pulleys, belt tensioners or belt setup, contributing to a proper correlation with in-vehicle assessment. Results obtained in a case study are presented in this paper, demonstrating the functional evaluation of the test rig and preliminary correlation data between in-vehicle testing and test rig monitored variables. Ultimately, benefits of the FEAD test rig are related to a significant reduction in the development time and number of prototype iterations during the evaluation of a real system application.