What is the purpose of diesel glow plugs?

The purpose of diesel glow plugs is to preheat the combustion chamber for easier starting. Diesel engines rely on compression ignition, where the air is compressed to a high temperature, causing the fuel to ignite. However, during cold weather or when the engine is first started, the temperature of the combustion chamber might not be sufficient to ignite the diesel fuel efficiently. Glow plugs heat the air inside the combustion chamber, ensuring that it reaches a temperature conducive to proper ignition of the fuel. This significantly aids in starting the engine under poor conditions, improving reliability and performance during low-temperature operations.

Understanding this function illustrates why it is so vital, especially in colder climates where starting a diesel engine can be particularly challenging without the aid of glow plugs. Other options pertain to different functions unrelated to the glow plugs' primary role, such as engine power output, cooling during operation, or fuel injection improvement.