What is the working principle of a four-stroke gasoline engine?
2 Answers
The working principle of a four-stroke gasoline engine is: 1. Intake stroke, the piston descends to draw in the air-fuel mixture; 2. Compression stroke, the piston rises to compress the mixture; 3. Power stroke, ignition burns the fuel, forcing the piston downward to perform work; 4. Exhaust stroke, the piston rises to expel the exhaust gases. Four-stroke engines belong to reciprocating piston internal combustion engines and are classified into three types based on the fuel used: gasoline engines, diesel engines, and gas fuel engines. The working principle of a four-stroke gasoline engine involves four stages: intake, compression, combustion (power), and exhaust, completing one working cycle. During this process, the piston moves up and down between the top and bottom dead centers four times, while the crankshaft rotates twice accordingly.
I've been driving for almost ten years, and the working principle of a four-stroke gasoline engine is quite easy to understand. It operates in four repeating steps: First is the intake stroke, where the piston moves downward, the intake valve opens, and the air-fuel mixture is drawn in. Next is the compression stroke, where both the intake and exhaust valves close, the piston moves upward to compress the mixture, heating it up. Then comes the power stroke, where the spark plug ignites the mixture, causing an explosion that expands and forcefully pushes the piston downward, releasing energy to drive the car. Finally, during the exhaust stroke, the exhaust valve opens, and the piston moves upward to push out the burnt gases for a clean exit. This cycle repeats continuously, keeping the engine running smoothly. If any part malfunctions—like a worn-out spark plug or leaking valves—the car may shake or lose power. During routine checks, I also pay attention to carbon buildup to avoid excessive fuel consumption, especially on long trips.
