Spark plug   (Dieselpartsworld) 2016-01-19    

Spark plug
The spark plug is the function of the ignition coil produced by the introduction of pulse high voltage electric combustion chamber, and the electrode between the electric spark, ignite the mixture, complete combustion.
The spark plug gap between the ignition coil and distributor can be produced by the high voltage of the ignition coil and distributor, therefore, the gap between the spark plug has a great influence on the ignition performance of the engine.
The gap is too small, weak spark, and because of the easy carbon deposition and leakage fault; gap is too large, the required penetration increased voltage. The engine is difficult to start, and in high speed prone to "misfire" phenomenon. Therefore, the gap between the spark plug center electrode and the side electrode should be appropriate, the spark plug gap between the 0.60-0.90mm.
Spark plug knowledge
Spark plug is the key part of the insulator, if the insulator does not work, high voltage power will be "cut path" without the poles into the ground, resulting in no spark phenomenon.
Spark plug insulator must have good mechanical properties and resistance to high voltage, high impact resistance, resistance to chemical corrosion, the ordinary spark ceodore using alumina based ceramic made. Spark plug size is unified in the world, any car can be general, but due to the type of gasoline engine is different, so the spark plug will be divided into two basic types, cold type and heat type.
Cold type and heat type are relatively speaking, it reflects the thermal characteristics of the spark plug. The spark plug to proper temperature can work well, no coke to work. Practice has proved that the spark plug insulator remain in the 500 - 600 DEG Ctemperature, fall on the insulator oil droplets can immediately burned to deposits will not form. Above this temperature will pre ignition, below this temperature coke. Temperature on different engines will not be the same, the designer will use the length of the insulator skirt to solve this contradiction.
Some skirt short small heating area, fast heat dissipation, so skirt temperature is low, said cold type spark plug is in high speed and high compression ratio of high power engine; some skirt slender large heating area, slow cooling, therefore skirt temperature is high, said hot spark plug is in low speed and compression ratio of the small power engine.