The primary function of a glow plug (preheater) is to provide heat energy for diesel engine starting in cold conditions. This heat raises the cylinder temperature by heating the combustion chamber or intake air, ensuring a smooth engine start.

Core Functions

Glow plugs are a key auxiliary component for cold-starting diesel engines. Their core functions include:

Improving starting performance: In extremely cold conditions, insufficient compressed air temperature can prevent the fuel from spontaneously igniting in a diesel engine. Glow plugs rapidly heat the combustion chamber or intake air (reaching over 850°C within 3 seconds), helping to achieve the necessary conditions for fuel self-ignition.

Reducing cold-start wear: Preheating reduces the increase in oil viscosity and the contraction of metal components caused by low temperatures, thereby reducing frictional losses during starting.

Working Principle

Glow plugs typically contain a resistance coil that heats rapidly when energized. Depending on the type (e.g., metal or ceramic), the heating rate and maximum temperature vary:

Metal glow plugs: They reach temperatures exceeding 850°C within 3 seconds and operate at approximately 1000°C. Ceramic glow plugs: Heat up faster (reaching 1000°C in 2 seconds) and can operate at temperatures up to 1150°C.

Applications

Mainly used in diesel engines, especially in cold regions or during winter. Some model aircraft engines also use glow plugs to ignite the fuel mixture.