What is the function of car spark plugs?

[JudeLynn]

Car spark plugs introduce high-voltage electricity into the combustion chamber and cause it to jump across the electrode gap to generate sparks, thereby igniting the combustible mixture in the cylinder. Spark plugs mainly consist of a terminal nut, insulator, terminal stud, center electrode, side electrode, and metal shell. Spark plugs are installed on the side or top of the engine. Early spark plugs were connected to the distributor via ignition cables, but over the past decade, most car engines have adopted direct connections between ignition coils and spark plugs. Working principle of spark plugs: The ground electrode of a spark plug connects to the metal shell, which is threaded into the engine block via the cylinder head. The insulator primarily serves to isolate the metal shell from the center electrode. The terminal nut is the part that contacts the high-voltage coil. When current passes through the terminal nut and center electrode, it breaks down the medium between the center electrode and ground electrode to produce sparks, thus igniting the air-fuel mixture in the cylinder.