Spark plugs are small but essential electrical devices used in internal combustion engines to ignite the air-fuel mixture inside the engine's cylinders. They deliver an electric current from the ignition system to the combustion chamber, creating a spark that ignites the compressed fuel and air mixture, which produces the explosion necessary to power the engine
. Structurally, a spark plug consists of a metal threaded shell that screws into the engine's cylinder head, a central electrode insulated by ceramic, and one or more ground electrodes. When high voltage from the ignition coil is applied, a spark jumps the gap between the central electrode and the ground electrode(s), igniting the fuel-air mixture
. The ignition caused by the spark forces the engine's pistons to move, converting chemical energy into mechanical energy that propels the vehicle. Besides igniting the mixture, spark plugs also help dissipate heat from the combustion chamber to prevent engine damage
. Spark plugs require very high voltage to operate—typically between 12,000 to 45,000 volts or more—to create a hot, long-lasting spark. Over time, spark plugs wear out due to repeated combustion and corrosion, which can lead to weaker sparks, engine misfires, or failure to start
. In summary, spark plugs are critical components that initiate combustion in gasoline engines by producing the spark necessary to ignite the fuel-air mixture, enabling the engine to generate power and run efficiently
