What is the working principle of an engine?

[DiDante]

The working principle of an engine is to convert other forms of energy into mechanical energy. The working principles of two-stroke and four-stroke engines differ, with most automotive engines being four-stroke. The working cycle of a four-stroke gasoline engine consists of four piston strokes: intake stroke, compression stroke, power stroke, and exhaust stroke. The intake valve opens, the exhaust valve closes, and the piston moves from top dead center to bottom dead center. The cylinder volume above the piston increases, creating a vacuum. The pressure inside the cylinder drops below the intake pressure, and under the vacuum suction, the gasoline atomized by the carburetor or fuel injection device mixes with air to form a combustible mixture, which is drawn into the cylinder through the intake manifold and intake valve. The intake process continues until the piston passes bottom dead center and the intake valve closes, after which the upward-moving piston begins to compress the gas.