What Type of Spark Plugs Are Used in Natural Gas Vehicles?

[DeSawyer]

For vehicles converted to use natural gas, specialized dual-fuel (natural gas and gasoline) spark plugs are employed. Currently, the mainstream product in the market is the NGK 79877988. First, it's a reputable brand, and second, it genuinely performs well—typically resolving issues immediately after installation. 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 threshold, the number of ions and electrons in the gas increases avalanche-like, causing the air to lose its insulating properties. A discharge channel forms in the gap, leading to a "breakdown" phenomenon. At this point, the gas becomes a luminous body, known as a "spark." Accompanying this, thermal expansion produces a "crackling" sound. The temperature of this electric spark can reach 2000–3000°C, sufficient to ignite the air-fuel mixture in the cylinder's combustion chamber.