P I S T O N A S S E M B L Y D E S I G N
he piston’s function is to act as a moveable plug in the cylinder, forming the bottom part of the combustion chamber. There’s a gas-tight seal between the piston and the cylinder wall - so the only way for the hot combustion gases to expand is by forcing the piston down. It’s the same principle behind a cannonball, but instead of flying off into someone’s beloved pirate ship, the piston is pushed back up the cylinder by the rotating crankshaft and the cycle repeats itself.
Over 60% of the friction inside the engine comes from the motion of the piston assembly, and so this is a major area of focus for improving the efficiency of engines. The piston is still seeing ongoing development and research as we’ll see in more detail shortly.
