Automotive Mechanisms for Improving Fuel Economy

This paper presents two mechanism innovations in the area of advanced propulsion systems. The first is a mechanism arrangement that couples the two cranks of an opposed piston variable compression ratio engine. This arrangement can vary the relative phasing between the two cranks to achieve compression ratio change. This strategy has been shown to improve fuel economy by approximately 5%, in certain engine applications. Secondly, the paper describes a high-speed flywheel system coupled to an automotive transmission. Its use as an alternative energy storage system for capturing vehicle kinetic energy has the potential to improve fuel economy by 15-20% when coupled to the driveline via a three-speed clutched transmission system.