What is the principle of a spark plug?
3 Answers
Spark plug working principle: The ground electrode of the spark plug is connected 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 of the spark plug that contacts the high-voltage coil. When current passes through the terminal nut and the center electrode, it ionizes the medium between the center electrode and the ground electrode, generating a spark to ignite the air-fuel mixture in the cylinder. Spark plug replacement interval: Under normal maintenance conditions, replacement is recommended after driving 40,000 to 60,000 kilometers. However, this may vary depending on the brand and engine type, so it's advisable to follow the owner's manual. The following standards can be referenced for maintenance replacement: Platinum spark plugs should be replaced at 40,000 kilometers, ordinary nickel alloy spark plugs at 20,000 kilometers, and iridium spark plugs at 60,000 to 80,000 kilometers.
The spark plug is something I frequently encounter issues with while driving. Essentially, it's a small component for engine ignition, relying on high-voltage electricity to create sparks between electrodes to ignite the gasoline-air mixture, making the engine run. When the current comes from the ignition coil, the voltage can reach tens of thousands of volts, instantly creating a small arc in the cylinder to trigger a mini-explosion that drives the piston. The principle is pretty cool, but if the spark plug wears out or gets carbon buildup, changes in the electrode gap—whether too large or too small—can affect ignition performance, leading to weak acceleration or unstable idle. From my experience, it's best to inspect them every 30,000 kilometers. Before replacing old spark plugs, clean the seat holes and avoid using the wrong type—for example, copper-core plugs suit regular cars, while platinum ones are more durable but pricier. In short, faulty spark plugs can cause hard starts and skyrocketing fuel consumption. Regular maintenance keeps the engine smooth, fuel-efficient, and makes driving much safer.
I'm a car tech enthusiast who loves delving into how these small components work. At the heart of a spark plug is electrical discharge—when the engine control unit sends a signal, high-voltage current passes through the electrode gap of the spark plug, ionizing the air to create a spark that ignites the air-fuel mixture. Electrode design is crucial; the gap between the center electrode and ground electrode must be precise, typically between 0.5 to 1 mm. Too small, and the spark is weak; too large, and the voltage is insufficient, leading to ignition failure. Materials like iridium can enhance spark intensity and lifespan. Overall, the spark plug works in tandem with the ignition coil to ensure instantaneous combustion. If it fails, engine efficiency drops significantly, leading to reduced power or even excessive emissions. I recommend buying genuine spark plugs—they're not hard to replace yourself, and choosing the right heat range and specifications can prevent common issues. Though the principle is simple, maintaining it well can improve fuel efficiency and driving experience.
