What is the function of a spark plug?
2 Answers
The function of a spark plug is to generate an electric spark to ignite the gasoline in the engine cylinder. The structure of a spark plug consists of a slender metal electrode passing through a ceramic material with insulating properties. The lower part of the insulator is surrounded by a metal shell, which is screwed tightly onto the cylinder head with threads. A welded electrode at the bottom of this metal shell forms a grounding connection with the vehicle body. At the central end of this electrode, there must be a tiny discharge gap. High-voltage current from the distributor passes through this central electrode and discharges at the gap at the bottom. At this point, the spark plug functions to generate an electric spark and ignite the air-fuel mixture, providing the engine with power and output.
Spark plugs play a crucial ignition role in car engines. I remember when I first disassembled and repaired an engine, seeing how they generate high-voltage electrical sparks to ignite the gasoline-air mixture, thereby driving piston movement to start the vehicle. If spark plugs are severely carbon-fouled or worn, the car may shake, have difficulty starting, or suffer from sluggish acceleration. I've seen many friends experience significantly increased fuel consumption and even require towing for repairs due to this issue. Modern spark plugs use iridium or platinum materials, extending their service life to tens of thousands of kilometers. Regular inspections, such as checking the electrode gap every 20,000 kilometers, can effectively prevent sudden failures. From daily driving experience, a healthy spark plug ensures smooth engine operation and reduces exhaust emissions, which is also beneficial for the environment.
