Fuel economy is one of the main drivers of the automotive industry. This subject is becoming more and more important showing a clear upraising relevance tendency. The automotive community is researching and developing many solutions and trending technologies to improve the internal combustion engine, realizing its existence is under risk due to strong greenhouse gas impact. Some innovative technologies focus on the internal combustion engines replacement by other energy conversion systems. Other new technologies improve internal combustion engines efficiency but, in most of the cases, impacts on its costs and consequently on its viability, especially considering the entry level passenger cars. In these applications, the cost impact is hardly acceptable by the customers and this market represents a considerable part of the global automotive industry. Any opportunity to improve the vehicle efficiency with minimum cost is welcome. This paper intends to assess the development and application of a gear shift indicator in an entry level passenger car. This technology represents a very low cost impact because the engine control unit should add just an improved software strategy that indicates the more efficient way to drive the vehicle. In order to compare the advantages of this technology, many numerical simulations were performed considering different test cycles and two main vehicle and road conditions: empty vehicle on a plain (0%) road grade compared to a loaded vehicle on a uphill (5%) road grade. The results presented 8% fuel economy improvement for the driver that follows the gear shift indicator compared to the traditional driver that considers only the vehicle speed for gear shifting  following a Brazilian homologation standard . This advantage in fuel economy is significant for the empty vehicle, increasing with lower cycle average speed. This paper highlights the importance of right shifting for fuel economy and reinforces the numerical simulation for time, test facility and of course costs.
Citation: Rovai, F., "Right Shifting for Fuel Economy," SAE Technical Paper 2019-36-0095, 2020. Download Citation
Fernando Fusco Rovai
VW do Brasil / Centro Universitário FEI