Design and Verification of Piston-Train Cam Linkage Mechanism

The D-cycle (Differential-Stroke cycle) utilizes a piston-train to operate its piston crown for the breathing strokes away from the skirt. This two-part piston design is called D-piston. A 4-cycle baseline gasoline engine is retrofitted into a D-cycle engine. This article describes the design and analysis of the piston-train and the cam profile used for the desired 4 differential piston strokes per revolution. The retrofit starts from CAD of parts that fit into the limited space in the engine case toward better layout and part design of the minimal cam-linkage dimensions and higher performance by CAE.