Analysis and Comparison of Epicycloidal and Hypocycloidal Internal Combustion Engine Mechanisms

Abstract

The analysis and comparison of epicycloidal and hypocycloidal mechanisms for the rotary four-stroke internal combustion engine are presented. The mathematical modeling for velocity and acceleration analyses of rotary pistons, based on the continuity of contact between the bar and the pin on the planetary gear, is developed. Expressions for the compression ratio and the transmission angle of cycloidal engine mechanisms are also derived. Two cycloidal engine mechanisms, one epicycloidal and the other hypocycloidal, with the same gear ratio and range of flywheel angle for the four-stroke cycle are analyzed and compared. The detailed kinematic analysis results identify the similarities and differences of these two cycloidal engine mechanisms. Several interesting features are observed and discussed.