What is the working principle of a gasoline engine spark plug?
1 Answers
Working principle of a gasoline engine spark plug: 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 central 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 central electrode, it ionizes the medium between the central electrode and the ground electrode, generating a spark to ignite the air-fuel mixture in the cylinder. The spark plug is installed on the side or top of the engine. In early designs, spark plugs were connected to the distributor via ignition cables. However, over the past decade, most passenger car engines have adopted direct connection between ignition coils and spark plugs. If a spark plug is damaged, it can directly cause issues such as electrical leakage in the vehicle's ignition system, increased fuel consumption, and reduced power output. The most critical problem is difficulty in ignition, affecting the vehicle's normal operation. Severe spark plug erosion—evidenced by pitting, damage, or melted electrodes at the spark plug tip—indicates that the spark plug is defective and should be replaced.
