1. the heat value of the spark plug
Spark plug heat value, the popular expression is the temperature of the spark plug skirt (wrap around the center electrode), which is usually represented by Arabic numerals. For example: the number 8 in the Bosch number F8DCOR. It should be particularly noted that this "8" does not refer to 8 degrees, but refers to a temperature range value represented by "8".
Since gasoline cannot be completely burned in the engine, there will be a small amount of carbon powder deposited on the center electrode and the side electrode of the spark plug. Accumulation to a certain extent will seriously affect the normal operation of the spark plug. However, if the temperature on the spark plug is high enough, these toners will burn by themselves. We call this toner its own combustion temperature range as the appropriate spark plug heat value for this engine.
The determination of the size of the spark plug's heat value is its structure. The skirt body we described earlier is an important term for spark plugs. The area of the skirt in contact with the air determines the heat value of the spark plug.
As shown above: The larger the area of the skirt in contact with the air, the better the heat dissipation of the spark plug, the lower the temperature of the spark plug itself, ie, the smaller the value of the spark plug; on the contrary, the contact area between the skirt of the spark plug and the air. The smaller the spark plug is, the poorer the heat dissipation is, the higher the temperature of the spark plug itself, ie, the greater the thermal value of the spark plug.
It should be noted that the Champion and Bosch spark plugs are represented by the lower the number, the higher the calorific value. The representation of NGK and Denso is that the higher the number is, the higher the calorific value is.