The middle metal shell and the ceramic body part of the spark plug, usually below 100 degrees C (or about 100 degrees C), is due to the close contact of the spark plug on the cylinder head, which carries a fast heat metal cylinder head and the water cycle to take away 80% of the heat. The engine water temperature, you know, is often below 100, and more than 100 degrees centigrade. Boil.
The following figure is a cycle diagram of a certain type of engine coolant. In order to illustrate, each cylinder has a water jacket and each cylinder is the heat that can be taken away by the liquid coolant (water).
The temperature of the spark plug basically refers to the temperature of the spark plug skirt, that is the extreme temperature of the spark plug and the temperature of the ceramic body near the electrode.
The normal operating range of the spark plug is 500 degrees C to 850 C, more than 900 C -1000 C, and it will go to the spontaneous combustion zone, that is to say, the spark plug has not begun to discharge and ignites, and the gasoline is ignited in advance, which may cause a detonation.
So the spark plug has calorific value. The essence of the calorific value is the maximum heat that the spark plug can bear or take away.
If a vehicle uses a spark plug with too low calorific value, the spark plug will be too hot, and it will probably knock.
If the vehicle uses a spark plug with high heat value and the spark plug does not keep the heat, the temperature of the work may be less than 500 degrees centigrade, the work is bad, the gasoline can not burn smoothly, causing the carbon of the spark plug.
On the cylinder head, it is easy to heat up to below 100 degrees (or left or right).
The heat value of the spark plug is usually adjusted by the size and the shape of the ceramic. The ceramic is more, the heat dissipation is slow, the heat value is low, the ceramics are less, the heat dissipation is fast, and the heat value is high.