What is a Spark Plug Made of?

[MorganLee]

A spark plug consists of a terminal nut, insulator, terminal stud, center electrode, side electrode, and metal shell. Spark plugs are installed on the side or top of an engine. In early designs, spark plugs were connected to the distributor via ignition cables. Over the past decade, most passenger car engines have adopted direct coil-on-plug ignition systems where ignition coils connect directly to spark plugs. Main types of spark plugs include: Standard spark plugs, projected insulator spark plugs, electrode spark plugs, seat spark plugs, surface gap spark plugs, and surface discharge spark plugs. Spark plug working principle: The spark plug's ground electrode connects to the metal shell, which is threaded into the engine block via the cylinder head. The insulator primarily isolates the metal shell from the center electrode. The terminal nut serves as the contact point for the high-voltage coil. When current passes through the terminal nut and center electrode, it ionizes the medium between the center electrode and ground electrode to generate a spark, thereby igniting the air-fuel mixture in the combustion chamber.