All about spark plug
The function of a spark plug is to produce a spark at the required time to ignite the combustible mixture. That spark will ignite the air fuel mixture inside the combustion chamber caused a big explosion and then that starts the power stroke of the engine.
How does a Spark Plug work
A spark plug in Dubai mainly consists of a steel shell which makes the outer covering, a resistance which controls the strength of current and two electrodes i.e. central electrode and ground electrode. Both these electrodes are made up of nickel alloy to with sand erosion and corrosion at high temperatures. A central electrode carries high tension current and is insulated using porcelain. Whereas the ground electrode is welded to the steel shell of the spark plug and thus gets grounded when attached to the cylinder head of the engine.
We know that during the engine operation when high tension current flows through the central electrode it ionizes the gas present between the electrodes also known as the electrode gap thus making it a conductor and hence produces a spark. Now as the tip of the central electrode and the insulator are exposed to the combustion gases there sustains a risk of cracking in the insulator due to high thermal stresses at very high temperatures. Also, sometimes in the less load conditions at the low temperatures abnormal surface deposit takes place at the tip and fouls the electrodes.
Types of Spark Plugs
Depending upon how these problems are addressed, spark plugs can be classified into two types which are as follows:
Hot spark plug: Hot spark plug have long insulated tip and long heat rejection path to avoid abnormal deposition on the tip and are used where the combustion chamber temperatures are relatively low such as in bikes and cars.
Cold spark plug: Cold spark plug do not have insulated tip and have short heat rejection path to avoid overheating and are used where combustion the chamber temperatures are relatively high such as in racing cars or trucks.
Spark plugs are determined by their size and the size of the spark plug is determined by the diameter of the threads. If we try to install the wrong size spark plug, we can cause anything from the spark plug not being able to be torque down to damage to the cylinder head in the form either cross threading or simply trying to jam a spark plug in a hole where it won't fit. Then we have the spark plug reach. The reach is going to be the length of the thread. Reach is also how far into the cylinder head the spark plug goes.
When to change or replace the spark plug?
It depends on several things such as the age and condition of your car's engine, the type of driving you do and the type of plugs you have all need to be considered. In general, it should be replaced after every 25 thousand miles or so. It is recommended that you should replace every plug and never try to just replace some of them.