What is a spark plug in a car?
3 Answers
Spark plug is an ignition device in a car used to ignite the combustible mixture inside the cylinder. The spark plug mainly consists of a terminal nut, insulator, terminal screw, center electrode, side electrode, and shell. The side electrode is welded to the shell. Under high voltage, the air between the center electrode and the side electrode of the spark plug rapidly ionizes, forming positively charged ions and negatively charged free electrons. When the voltage between the electrodes reaches a certain value, the number of ions and electrons in the gas rapidly increases, causing the air to lose its insulating properties. A discharge channel forms in the gap, leading to a breakdown phenomenon. At this point, the gas becomes a luminous body, and as it heats and expands, it is sufficient to ignite the mixture in the cylinder's combustion chamber.
As someone who has been driving for over a decade, I've always considered spark plugs to be like the little heart of a car engine. Every time you start the ignition, it sparks inside the cylinder, instantly igniting the air-fuel mixture to power the engine. This small component is usually located on the cylinder head. If it's worn out or has too much carbon buildup, the car may shake, have difficulty starting, or even stall on the road. I remember one time when my car lacked power during acceleration, and a trip to the repair shop revealed it was a spark plug issue—replacing it immediately made the car run much smoother. I recommend checking them every 20,000 to 30,000 kilometers. Choosing high-quality brand spark plugs can extend their lifespan and improve efficiency. Don't underestimate them; they can be crucial for safety in critical moments.
Since childhood, I've been learning car repair from my dad, and spark plugs stand out as a core component in my memory. They connect to the ignition coil, generating a high-voltage electric spark between the electrodes during the engine's compression stroke to ignite the air-fuel mixture, thereby driving the piston movement. Nowadays, mainstream spark plug materials include nickel alloy and iridium, with the latter being more durable and offering stable heat values. During repairs, I often find that aged spark plugs with cracked insulators or eroded electrodes can cause engine misfires or unstable idling. Regular cleaning and replacement not only prevent these issues but also improve fuel efficiency and reduce emissions.
