How Many Spark Plugs Does a Four-Cylinder Engine Have?

[TheoMarie]

Each cylinder has only one spark plug, so a four-cylinder engine has four spark plugs. A four-cylinder engine, also known as a four-cylinder motor, is a machine that converts one form of energy into another more useful form. The spark plug is a crucial component of the gasoline engine's ignition system. It introduces high-voltage electricity into the combustion chamber and causes it to jump across the electrode gap, generating a spark that ignites the combustible air-fuel mixture in the cylinder. Under high voltage, the air between the spark plug's center electrode and the side electrode rapidly ionizes, forming positively charged ions and negatively charged free electrons. When the voltage between the electrodes reaches a certain level, the number of ions and electrons in the gas increases like an avalanche, causing the air to lose its insulating properties. A discharge channel forms in the gap, resulting in a "breakdown" phenomenon. At this point, the gas becomes a luminous body, known as a "spark." Along with the heat and expansion, a "crackling" sound is also produced. The temperature of this electrical spark can reach as high as 2000–3000°C, which is sufficient to ignite the air-fuel mixture in the cylinder's combustion chamber.