Kinematic and Dynamic Performances of the Hypocycloid Gear Mechanism for Internal Combustion Engine Applications

Internal combustion (IC) engines incorporating the conventional slider-crank mechanism are subjected to high frictional power losses mainly due to the piston-rod assembly. Due to its simplicity, IC engines have utilized this mechanism almost unchanged since its introduction. This study introduces the hypocycloid gear mechanism (HGM) as an alternative to the conventional slider-crank mechanism for IC engine systems. The HGM provides several advantages that allow for enhancing both the thermal and mechanical efficiencies of IC engines. In this study, the kinematic and dynamic performances of the HGM engine are analyzed in detail. The geometric relations of the HGM are used to derive the kinematic equations that describe the piston motion. These equations are then used to derive the dynamics equations considering gas and inertia forces acting on the HGM. This study also investigates the effect of attaching a flywheel to the HGM engine and suggests a mass-balancing approach for the engine. The results show that the HGM engine can achieve better engine performance in terms of the output torque, and there is a chance to perfectly balance the HGM engine.