How to Identify the Model and Specifications of Torch Spark Plugs?

[MacFinn]

The model number is located on the spark plug shell, representing material, size, heat value, resistance, and gap. Spark plugs are critical components in a gasoline engine's ignition system. They introduce high voltage into the combustion chamber, causing a spark to jump across the electrode gap, thereby igniting the combustible air-fuel mixture in the cylinder. Under high voltage, the air between the spark plug's center electrode and side electrode rapidly ionizes, forming positively charged ions and negatively charged free electrons. When the voltage across the electrodes reaches a certain level, the number of ions and electrons in the gas increases like an avalanche, causing the air to lose its insulating properties. This creates a discharge channel across the gap, resulting in a "breakdown" phenomenon. At this point, the gas forms a luminous body known as a "spark." Along with thermal expansion, a "crackling" sound is produced. The temperature of this electric spark can reach 2000–3000°C, sufficient to ignite the air-fuel mixture in the cylinder's combustion chamber.