Artigo Completo:

The Brazilian “Inovar-auto” tax program brings the need to improve engine fuel efficiency. In this paper, the impact on fuel savings by using low friction components was evaluated on representative Brazilian ethanol fueled engines. The vehicle certification cycles, and the typical urban drive, focus on low engine speed- loads where the mechanical losses are around 10% of the fuel energy. To define design changes on the engine components with more fuel saving potential, a proprietary simulation tool was used. After the selection of the design changes with greater potential, the engine was tested in a dedicated dynamometer cell with engine control, accuracy on fuel consumption measurement and fast acceleration transients needed to reproduce the fuel consumption cycles. The comparison between the baseline and the proposed lower friction components was done by 3 methods: a) motoring torque b) fuel consumption mapping, with average weights representative of the homologation cycles c) engine transient cycles, where the vehicle FTP75 and highway cycles were reproduced in the engine dynometer. The proposed lower friction components showed 2 to 6% fuel saving on the tested engines.