The method of Front End Auxiliary Drive (FEAD) system optimization can be divided into two ways. One is to use a mechanical device that decouples crank pulley from torsional vibration of crank shaft by using characteristics of spring. The other is to control belt tension through auto-tensioner in addition of alternator pulley device.
Because the former case has more potential to reduce belt tension than the latter case, the development of mechanically decoupled crank pulley, despite of its difficulty of development, is getting popular among the industry.
This paper characterizes latest crank pulley technologies, Crank Decoupler and Isolation Pulley, for torsional vibration reduction through functionality measurement result which composed of irregularity, slip, tensioner movement, belt span vibration, bearing hubload of idler and so on. Also it investigates their potential of belt tension reduction through steady state point fuel consumption test on dynamometer.
The result shows, approximately 0.6% fuel economy improvement is possible with about 37% reduction of belt tension.