What is the function of a car spark plug?

[Franklin]

The function of a spark plug: The ground electrode of the spark plug is connected to the metal shell, which is threaded into the engine block via the cylinder head. The insulator primarily serves to isolate the metal shell from the central electrode. The terminal nut is the part of the spark plug that contacts the high-voltage coil. When current passes through the terminal nut and the central electrode, it breaks down the medium between the central electrode and the ground electrode, generating a spark to ignite the air-fuel mixture in the cylinder. Spark plug replacement interval: Under normal maintenance conditions, replacement is recommended after driving 40,000 to 60,000 kilometers. However, this may vary depending on the brand and engine type, so it's advisable to follow the user manual. The following standards can be referenced for maintenance replacement: Platinum spark plugs should be replaced at 40,000 kilometers, ordinary nickel alloy spark plugs at 20,000 kilometers, and iridium spark plugs at 60,000 to 80,000 kilometers.