Piston Ring Projection and Catching in Cylinder Ports of Two-Stroke Cycle Engine

Abstract

In a two-stroke cycle engine, the piston and its piston rings slide over the cylinder wall and its cylinder ports. This study investigates how those piston rings project and catch in cylinder ports, and examines the effects of engine speed and round chamfered ports on projection and catching. Strain gauges were installed on the bottom of the top and second rings, over the intake and exhaust ports. The variation of strain was then observed over each engine cycle. The piston behavior was then analyzed to consider ring projection and catching in ports. Results suggest the rings indeed project and catch in the ports, immediately after the piston moves from the intake port side to the exhaust port side, and again when the piston continues moving along the exhaust port on the upward stroke. Engine speed had a minimal effect on this projection and catching. However, larger round chamfered ports might decrease the second ring projection and catching in the exhaust port.

Keywords

• two-stroke cycle engine
• piston ring
• cylinder port
• piston behavior
• strain