Future Trends in the Conceptual Design Alternator Pulleys

Alternators used to have a solid pulley to connect it to the Front-End Accessory Drive (FEAD) system. Lately, new breakthrough designs have been developed for some applications, as the Overrunning Alternator Pulley (OAP) and the Overrunning Alternator Decoupler (OAD), with the aim to detach the alternator from the FEAD during high speed transients and to reduce the transmission of torsional vibrations from the internal combustion engine to the engine accessories, respectively. The downsizing of the internal combustion engine and its reduced idle speed to improve fuel economy and emissions led to belt slip or creep, increased NVH issues as chirpy noise or bearing reduced life due to the high vibration levels. Besides of that the increased demand for electric/electronics on-board systems led to the use of larger alternators, with bigger inertia, generating even higher vibration levels. The aim of this research is to review alternator pulley design evolution using a systematic approach to engineering design which evolves from the definition of the global function and development of the functional structure through the identification of solution principles and concept generation and prioritization. Conclusions of the research indicate how current designs could evolve to meet future trends in performance and reliability of the FEAD systems.