1. Quasi-type spark plug: The insulator skirt is slightly retracted into the end face of the casing, and the side electrode is outside the end face of the casing, which is the most widely used one.
2, the edge of the protruding spark plug: the insulator skirt is longer, protruding beyond the end face of the shell. The utility model has the advantages of large heat absorption and good anti-pollution ability, and can be directly cooled by the intake air to lower the temperature, and thus is not easy to cause hot ignition, so the heat adaptation range is wide.
3, electrode type spark plug: its electrode is very thin, characterized by strong sparks, good ignition ability, in the cold season can also ensure that the engine starts quickly and reliably, the heat range is wide, can meet a variety of purposes.
4. Seat type spark plug: The housing and the screwing thread are tapered, so that the gasket can be used to maintain a good seal, thereby reducing the volume of the spark plug, which is more advantageous for the design of the engine.
5, the pole type spark plug: the side electrode is generally two or more, the advantage is that the ignition is reliable, the gap does not need to be adjusted frequently, so it is often used on some gasoline engines where the electrode is easy to ablate and the spark plug gap can not be adjusted frequently.
6. Face-flash type spark plug: that is, the creeping gap type, which is the coldest type of spark plug, the gap between the center electrode and the end face of the casing is concentric.