The Internal Structure Of The Spark Plug

The spark plug consists of the following parts: 1. Wiring nut; 2. Central electrode; 3. Ground electrode; 4. Metal shell; 5. Insulator. The ground electrode on the spark plug is connected to the metal housing, which is connected to the engine block by the cylinder head threaded connection. The insulator mainly plays the role of isolating the metal shell and the central electrode. The wire nut is the part of the spark plug that is in contact with the high-voltage coil. After the current passes through the wire nut and the central electrode, it breaks down the medium between the central electrode and the ground electrode to generate sparks, thereby igniting the mixture in the cylinder.