The spark plug ignites the mixture and has the function of a lighter. In order to function as a lighter, the spark plug should work under very harsh conditions.

 

 

It is the performance of the ignition and combustion of the mixture through the spark plug. The combustion process from ignition to mixture between spark gaps can be divided into four stages.

 

The third stage in the whole process，the anti-inflammatory effect of the spark plug electrode (center and outer side) (the effect of the electrode taking away the thermal energy of the nucleus of the fire) may extinguish the fire of the ignited nucleus, causing the ignition to fail.This anti-inflammatory effect should be minimized, and the growth of the fire nucleus directly affects the performance of the ignition.

 

 

The spark plug must dissipate the heat from the combustion gas. The calorific value of the spark plug is the degree of heat dissipation.

 

 

 

Depending on the state of combustion, the suitability of the spark plug and the state of the engine can be judged.