Reduction of Parasitic Losses in Front-End Accessory Drive Systems: Part 2

Demanding CO₂ and fuel economy regulations are continuing to pressure the automotive industry into considering innovative powertrain and vehicle-level solutions. Powertrain engineers continue to minimize engine internal friction and transmission parasitic losses with the aim of reducing overall vehicle fuel consumption. In Part 1 of the study (2017-01-0893) described aspects of the test stand design that provides flexibility for adaptation to various test scenarios. The results from measurements for a number of front-end accessory drive (FEAD) components were shown in the context of scatterbands derived from multiple component tests. Key results from direct drive and belt-driven component tests were compared to illustrate the influence of the belt layout on mechanical efficiency of the FEAD system. The second part of the series will focus exclusively on the operation of the alternator. Two main elements of the study are discussed. The first part explores tests performed to evaluate the main design aspects of the component. Different belt designs, routing, and tension levels were tested and compared. A resulting matrix allows to determine an optimized belt design and layout for a specific vehicle configuration. In the second part of the study, the authors developed smart charging algorithms that allow for system charging while improving fuel consumption. The strategies were compared to the original vehicle-level configuration and a developed model compared the total fuel consumption benefit. With optimized and smart charging algorithms, the authors found approximately 2% fuel economy saving potential over real-world test cycle. Results for all tests and comparison between different alternators are presented and discussed in detail.