What is the working principle of an engine?
2 Answers
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.
The working principle of a car engine is actually quite ingenious; it operates like a continuously cycling mini-factory. Simply put, there are four main stages: during the intake phase, air and gasoline mix and enter the cylinder; in the compression stage, the piston moves upward to compress the mixture, making it denser; during ignition, the spark plug emits a spark, igniting the gas and causing an explosion that generates immense pressure; finally, in the exhaust phase, the piston pushes out the waste gases. This explosion forces the piston downward, converting the motion into rotational force via the connecting rod and crankshaft, which drives the wheels forward. This entire process repeats multiple times per second, relying on precise coordination. Modern engines optimize efficiency by controlling fuel injection volume and ignition timing to reduce fuel consumption and emissions. When driving, I always feel the throttle response—this system design ensures smooth acceleration, and timely maintenance, such as changing the oil and air filter, can extend its lifespan.
