Technical Paper
A Study Concerning the Noise and Vibration Characteristics of an Engine with Multiple-Link Variable Compression Ratio Mechanism
2005-04-11
2005-01-1134
The authors have previously proposed an engine system that uses a new piston-crank system incorporating a mulitiple-link mechanism to vary the piston's position at top dead center and thereby obtain the optimum compression ratio matching the operating conditions. This multiple-link variable compression ratio (VCR) mechanism can be installed without increasing the engine size or weight substantially by selecting a suitable type of link mechanism and optimizing the detailed dimentions. We have previously reported that this system provides additional benefits by reducing second-order inertial forces and the friction losses caused by piston side thrust in the combustion and expansion processes. This paper first describes the further improvements made to the link dimensions since our previous report. An improved link geometry is presented in which the centerline of the cylinder bore is offset in the opposite direction from that of existing internal combustion engines.