Efficiency analysis of different automotive front-end accessory drives layouts with the implementation of multibody simulation

This thesis reports on a study and research activity carried out at Dayco S.r.l.. The aim of this work was to set up a BSA bench configuration in order to perform immediate efficiency measurements on different Front End Accessory Drives (F.E.A.D.) layouts. The whole activity is part of a global picture directed towards the CO2 emissions reduction. On this type of bench, a BiSG (Belt Integrated Starter Generator) hybrid solution or P0 architecture of an internal combustion engine is replicated: consists of a 12 or 48 V electric motor directly inserted in the F.E.A.D. and substituting the classical alternator. The bench is equipped with a three-phase synchronous electric motor that simulates the functionality and load conditions of an internal combustion engine. Two kinds of belt, a simple torsional vibration damper, a bearing decoupler, an high efficiency decoupler and a standard decoupler are tested in five different combinations. All the set-ups undergo different load conditions: a torque ramp on the BiSG electric motor is kept in all the tests, the crankshaft ran at 800 and 1500 rpm without and with torsional vibration. Power losses in the whole system are quantified by comparing power acting on BiSG and crankshaft. This activity allows to understand which F.E.A.D layout has highest efficiency under the different load conditions. Together with the practical test activity, a multibody dynamic model of one of the examined configurations has been developed on the simulation platform SIMDRIVE 3D. The theoretical outcomes are validated by comparison with real measurements: the simulative model might be a diagnostic device for future applications as well as a way to explain in detail test results.