What are Glow Plugs and how do they Work?
In our previous article, we explained how to identify when it’s time to replace your engine’s glow plugs. Even though they are more of a legacy product, fitted in older engine technology, we thought you may like to understand how glow plugs work and, essentially, what their function is within your diesel engine.
What are glow plugs?
Glow plugs are a vital component for your diesel engine. They are pencil shaped and made of metal, with a heating element at the tip. Not to be confused with spark plugs which are used in petrol engines, glow plugs are used exclusively in diesel engines and prove particularly useful in the winter when diesel engines can struggle to ignite fuel when cold.
How do glow plugs work?
Glow plugs essentially work by a three-step process:
- Pre-heating, where the glow plugs heat up quickly to start the engine
- Temperature maintenance- this is where the glow plugs will remain at a high temperature, thus ensuring optimal combustion within the diesel engine
- Post-heating, where the glow plugs stay heated for a few minutes after the engine has started up, meaning that the process of combustion is maintained for the duration of the engine’s operation
Since diesel engines require fuel, oxygen and an ignition point, glow plugs provide the ignition point to help the engine start up, even in colder temperatures. The glow plug contains an element – a small coil of wire – which is electrified during the ignition process. This emits a visible light (hence the term ‘glow’ plugs) once heated. Upon heating, intake air into the engine is compressed and the fuel injectors spray fuel onto the hot tip of the glow plug. Following this, injected fuel mixes with the compressed air, the fuel evaporates with the heat of the glow plugs, and the process of combustion takes place.
When should I replace my glow plugs?
So, know that we’ve covered what they are and how they work, how can you tell when it’s time to replace your heavy machinery’s glow plugs?
Signs that it’s time to replace your engine’s glow plugs
- Hard starting- if your engine refuses to fire or will not start, then this could mean that your glow plugs are damaged or faulty
- Misfire on start-up- if you’ve started your engine, but it isn’t firing properly, it could mean that you have a faulty glow plug, especially if accompanied by an unusual noise or knocking sound
- Smoking – unusual amounts of smoke upon your engine’s start-up could be a sign that glow plugs need changing, so switch off your engine and inspect for faults
As one of the UK’s leading parts suppliers, Jaytrac provides replacement Engine Parts, including glow plugs, for Caterpillar, Cummins, Komatsu, Volvo and many other machinery manufacturers. For any enquiries or for more information, please get in contact with our team of experts today at sales@jaytrac.co.uk or on +44 (0) 1604 491133 . Alternatively, fill out a contact form and we’ll get back to you as soon as possible.