Glow Plugs

Why are glow plugs fitted?

DIESEL ENGINES have spontaneous ignition, which means that the injected fuel does not require a spark to ignite it. The high temperature, which occurs as a result of compressing intake air, is sufficient to ignite the fuel.

However, in cold conditions, more energy is required to help ignition at start because both the intake air and the engine itself are colder and compression and pumping losses are higher too. Therefore, in diesel engines, glow plugs are a key factor for every cold start. At low ambient temperatures they heat the combustion chamber sufficiently to allow stable combustion conditions for the injected fuel.