What is the purpose of an ignition coil?
3 Answers
The purpose of an ignition coil is: The resistor added to the low-voltage circuit of the ignition coil is used to balance the high-voltage spark. At low engine speeds, the magnetic field can reach saturation, while at high engine speeds, due to the shortened time, the magnetic field cannot reach saturation, resulting in insufficient secondary voltage and weakened sparks. Ignition coils are divided into open-core and closed-core types based on the magnetic circuit. Traditional ignition coils use an open-core design, with the core made of silicon steel sheets about 0.3 mm thick, wound with secondary and primary coils. Closed-core types use an III-shaped core to wind the primary coil, with the secondary coil wound outside, and the magnetic lines of force form a closed magnetic circuit through the core.
I've driven quite a few old cars before. The purpose of the ignition coil is to boost the 12-volt low voltage from the battery into thousands of volts of high voltage, which is then transmitted to the spark plug for ignition, allowing the gasoline-air mixture in the engine to ignite and start. I remember once when I was on a long drive, the ignition coil suddenly failed, and the car shook all the way as if it were dancing, with no power to accelerate. It only returned to normal after spending some money to replace it. Actually, its principle is quite simple, like a transformer: the primary coil accumulates energy when powered, and the moment it disconnects, high voltage is generated in the secondary coil—the key is durability. In daily use, coil aging is often caused by vibration or overheating, with symptoms including difficulty starting, a sudden increase in fuel consumption, or even the emission warning light coming on. I suggest car owners pay more attention to idle stability and not underestimate this component; otherwise, breaking down halfway can be troublesome. Regularly checking the spark plugs can also help reduce stress on the coil. Looking back now, I had to repair my car often when I was younger, and the ignition coil taught me to prevent problems early, making driving more reassuring.
As a car electronics enthusiast, the role of ignition coils in modern engines is pretty cool. They're like little magicians in the ignition system, specializing in instantly converting the battery's low voltage into high voltage to ignite the air-fuel mixture in the cylinders via spark plugs, ensuring smooth engine operation. If the coil fails, the ECU might throw an error code, leading to misfires, shaky performance, sluggish acceleration, or triggering the emissions warning light. From my hands-on testing, aging coils are prone to overheating and failure, but newly designed integrated coils are more reliable. For instance, coil-on-plug systems with one coil per cylinder are more precise and efficient than old distributor systems. Importantly, coil performance directly affects combustion efficiency - optimized coils can slightly reduce fuel consumption while boosting power, making aftermarket high-performance coil upgrades a popular mod in the tuning scene. Don't forget to regularly diagnose wiring contact points, as electrical faults can remain latent for long periods.
