How are spark plug models classified?

[Nathan]

Spark plug models can be classified by material into: nickel alloy spark plugs, platinum spark plugs, and iridium spark plugs; by shape into: standard spark plugs, extended tip spark plugs, electrode spark plugs, seat spark plugs, pin spark plugs, and surface gap spark plugs. Spark plug replacement cycle: 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, so it's advisable to follow the user manual. The following maintenance standards can be referenced: 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. Spark plugs are installed on the side or top of the engine. Early spark plugs were connected to the distributor via ignition cables, but over the past decade, most car engines have switched to direct connection between the ignition coil and the spark plug.