Vehicle mechanics zone

The mechanics zone presents engine construction, the movement of pistons and cylinders, and the brakes of older cars. Instead of another vehicle silhouette, the focus is on components. They have specific jobs: producing movement, transmitting it or reducing speed. In a piston engine, gases produced by combustion exert pressure on a piston. It moves inside a cylinder rather than rotating with the car’s wheels. This is reciprocating motion: movement backwards and forwards.

The connecting rod and crankshaft turn that movement into rotation. The connecting rod links the piston to the shaft, and successive piston strokes drive the rotating mechanism. Watching a piston move therefore reveals only part of the process of transmitting power.

A four-stroke engine has intake, compression, power and exhaust strokes. One complete cycle takes two crankshaft revolutions. Following this relationship helps explain the mechanism: four successive piston strokes correspond to two revolutions, with combustion occurring at a particular stage of the cycle.