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How does an internal-combustion engine turn gasoline explosions into wheel motion?

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A diagram displays six types of simple machines with labeled illustrations: inclined plane, wedge, screw, lever, wheel and axle, and pulley, each shown with real-world examples like ramps, axes, screws, seesaws, door handles, and pulleys lifting objects. — machine Six simple machines for transforming energy into work.

An internal-combustion engine converts the energy released by gasoline explosions into rotational motion through a series of mechanical steps.1

In a typical four-stroke engine, a mixture of air and fuel is drawn into a cylinder, compressed, and ignited. The resulting combustion creates hot, expanding gases that push against the face of a piston, forcing it to move.21

This linear, or reciprocating, motion is converted into rotation by a connecting rod, which links the piston to an offset portion of the crankshaft. As the piston moves, it forces the crankshaft to turn.3

Finally, this rotational power is transferred to the vehicle's wheels through a transmission. The transmission acts as a speed-changing device, allowing the engine to operate at its most efficient speed while adjusting the torque and rotational speed delivered to the wheels based on driving conditions.45