||The piston assembly transfers the force from the power stroke to the crankshaft. Its design depends on the type of engine, its speed and compression ratio.
||Piston rings keep a tight seal within the cylinder to stop the heat and pressure in there from escaping. They also stop oil passing up into the combustion chamber.
||The connecting rod joins the piston to the crankshaft. It is fastened to the piston at its little-end by a piston pin, or gudgeon. It must be very strong, rigid, and as light as possible.
|Compression ratio||An engine's compression ratio can be a guide to the power it can generate, the higher the engine's compression ratio and the more powerful the engine.|