What is the working principle of automobile engine?

The working principle of automobile engine is mainly to convert chemical energy into mechanical energy.

The engine has sufficient power because the piston in the engine cylinder moves back and forth by burning the fuel in the cylinder, which is also a working cycle.

The power of the engine is because the piston in the engine cylinder drives the connecting rod on the piston and the crank connected with the connecting rod to burn while reciprocating, and the center of the crankshaft has been reciprocating circularly to output power.