What the Hell Is… a Four-Stroke Engine?
What the Hell Is… a Four-Stroke Engine?
Every time you start your car, thousands of tiny explosions begin pushing metal pistons up and down, converting burning fuel into mechanical motion. The remarkable part? This controlled violence happens thousands of times every minute.
Most gasoline-powered cars use a four-stroke engine, a design developed in the 19th century and still fundamental to modern motoring.
The four strokes are surprisingly simple.
- Intake: The piston moves downward, drawing air and fuel into the cylinder through an open intake valve.
- Compression: Both valves close as the piston rises, squeezing the mixture into a smaller space.
- Power: A spark plug ignites the compressed mixture. Expanding gases force the piston downward, turning the crankshaft and ultimately driving the wheels.
- Exhaust: The piston rises again, pushing burned gases through the exhaust valve.
Then the cycle repeats.
Each cylinder produces one power stroke for every two crankshaft revolutions. At 6,000 RPM, that’s 50 power strokes per second per cylinder.
In a four-cylinder engine, that’s 200 power strokes every second.
Your engine isn’t simply burning gasoline. It’s conducting a precisely timed mechanical orchestra of pressure, heat, combustion, and motion.
And your right foot is the conductor.