What is the function of glow plugs in an engine?

Glow plugs serve a crucial role in diesel engines by preheating the air in the combustion chambers. This preheating process helps facilitate the ignition of the diesel fuel when the engine starts, especially in cold weather conditions. Diesel engines rely on compression to ignite the fuel, and having a sufficiently warm air charge improves the combustion efficiency and reduces starting difficulties.

The effectiveness of glow plugs is particularly important because diesel fuel requires higher temperatures to ignite compared to gasoline. Thus, by heating the air within the cylinders, glow plugs enhance engine performance during startup and help ensure smoother operation. This function is especially significant in colder climates where low temperatures can hinder the engine’s ability to start effectively.