Is the spark plug continuously working during engine startup?

[Talia]

During engine startup, the spark plug is continuously working. Its working principle involves generating an arc between the electrodes through voltage to ignite the air-fuel mixture in the cylinder, thereby maintaining the normal operation of the engine. The function of the spark plug is to discharge the high-voltage pulse electricity delivered by the high-voltage wire, break down the air between the two electrodes of the spark plug, and generate an electric spark to ignite the air-fuel mixture in the cylinder. Automotive spark plugs are categorized into: 1. Standard spark plugs: The insulator skirt is slightly recessed into the shell end face, and the side electrode is outside the shell end face; 2. Insulator-protruding spark plugs: The insulator skirt is longer, protruding beyond the shell end face; 3. Fine-electrode spark plugs: The electrodes are thin, characterized by strong sparks and better ignition capability.

[VonAlice]

Spark plugs indeed work continuously during the engine starting process, which I'm quite familiar with. When starting the engine, as you turn the key, the engine control unit makes the spark plugs fire repeatedly to ignite the air-fuel mixture until the engine runs stably. After starting, once the engine is running normally, the spark plugs no longer receive continuous current; they only work once at the end of each cylinder's ignition stroke to ignite the fuel. This means the starting phase is when spark plugs are busiest. If spark plugs are aged or fouled, it may cause delayed starting or failure to start. I once ignored this issue while driving and ended up stranded on the road, but replacing the spark plugs promptly solved the problem. I recommend checking them every two years or 30,000 kilometers, as cold starts in winter put them to the test. Understanding these small details can help you handle emergencies more easily and reduce repair costs.

[BellaLynn]

From a technical perspective, the spark plug is continuously active during engine startup. As an automotive systems enthusiast, I understand that during the starting process, the spark plug receives power from the ignition coil and discharges continuously to ignite the air-fuel mixture, assisting the engine in accelerating from a standstill. Once successfully started, the spark plug operates intermittently according to the firing order, triggering a single spark only at the end of the compression stroke. It is not a continuously powered component. Insufficient voltage or excessive spark plug gap can reduce starting efficiency; I've personally tested the voltage of spark plugs in older vehicles using a multimeter and found that values below standard can cause difficult starting. Maintaining spark plugs is crucial—regularly cleaning carbon deposits and checking the gap helps prevent ignition failures. Don't overlook the coordinating role of the electronic control unit, as the system adjusts ignition timing to ensure smooth startups.

[VonCollin]

When I first learned to drive, I was also curious about spark plugs. When starting the engine, the spark plugs continuously fire to ignite the fuel and power the engine, like a switch repeatedly closing. Once the engine is running, during normal driving, they only spark when needed. Don’t worry about them constantly consuming electricity—this design saves energy. I often encounter slow starts due to dirty spark plugs, but a simple cleaning or replacement solves the issue. Regularly checking spark plugs can improve startup speed and extend engine life. Don’t overlook small components—they make a big difference.