A petrol engine is an internal combustion engine that uses petrol (gasoline) as fuel. It works by mixing air and petrol, which is then compressed and ignited by a spark from the spark plug. This combustion creates energy that powers the engine, allowing vehicles like cars and motorcycles to move. Petrol engines are commonly found in many everyday vehicles due to their efficiency and performance. They typically produce less torque than diesel engines, but they can achieve higher speeds. The design of a petrol engine can vary, but they generally consist of components like the cylinder, piston, and crankshaft.