What is a Glow Plug? Features, Types, uses

The glow plug is a longer-sized, thin metallic component that has a heating component on the tip. For heating elements, such materials are used that have good temperature handling capability with oxidation. In a vehicle, it is an important part of the engine, and its working is like the spark plug of a petrol engine that starts the engine.

Spark plugs provide spark ignition, and glow plugs heat the air and fuel mixture that produces ignition in the car engine. In this post we will cover the features of glow plugs and how they work.

What Is A Glow Plug?

• The glow plug engine, or glow engine, is part of a small internal combustion engine that is used in aircraft and cars.
• Its ignition is done with heating from compression, heating of the glow plug, and the catalytic effect of platinum in the glow plug on methanol in fuel.

• The design of a glow plug is like a spark plug, and both are pencil-shaped metallic components that come with a connector at the upper part for wire connection.
• • The glow plug is a thin design, so the lower part of the heating element is like a toaster component.
• Glow plugs are diesel truck components that help to start diesel engines in low temperatures.
• Plugs come with a heated element at the upper part that glows due to electrification.
• The main use of glow plugs is the ignition of fuel in a cold engine that provides fast starting.

Diagram Of A Glow Plug

• Glow plugs come in different designs, but commonly used are hexagonal-shaped heads and thin, threaded center units that provide easy connection and removal.
• Thread helps the cylinder to make a strong fitting. The heating element of the glow plug comes with a heating coil at one end point.
• • The heating element heats the air-fuel mixture for providing engine starting. The electrical connector lies on the other side of the glow plug. This point provides power for operating the heating element.
• Main parts of glow plug are as
• Heating coil
• Terminal nut
• Thread
• Insulation powder,
• A metal or ceramic shell covers the exterior.
• Regulating coil
• Center electrode

Glow plug working

• The glow plug is a heating element that heats fuel and air for providing fuel combustion in a diesel engine.
• Fuel combustion starts the engine for driving the vehicle. Each cylinder of the engine comes with one glow plug in the prechamber or in the combustion chamber.
• Glow plugs are used for starting the engine in low-temperature conditions through preheating air in the combustion chamber that helps get the ignition temperature fast.
• When we are on ignition, glow plugs operate automatically and continue the active process for some seconds.
• In currently used vehicles glow plugs are made with ceramic or metals.

 Types of Glow Plug

• There are different types of glow plugs that come with certain features and uses.

Pressure Sensors Glow Plug (PSG)

• These glow plugs come with sensors and electronics in psg pin for managing working that also reduces emissions. Some of the latest PSG work uses a sensor for measuring pressure in the combustion chamber and sends a signal to the engine management electronics that helps to measure the heating of the glow plug.

Ceramic Glow Plugs (CGP)

• It is used for high-temperature conditions like 1500 degrees in a short time. Its high-speed heating provides fast engine start. It is beneficial for use with low-combustion diesel engines; that is according to EPA regulations.

High-Tech Steel Glow Plug

• It comes in two further types, like GE and GN. Modern three-phase glow plugs are GN plugs that get heated quickly and hold heat until ignition; after that, they cool in a short time.
• This plug is like a longer pencil, and some high-tech steel plugs are heated in just 7 to 8 seconds, unlike other diesel engines that are heated in 30 seconds or take more time.

Bad Glow Plug symbols

 Exhaust Smoke

• If you observe white and black smoke from the exhaust, that is a sign of fault. If there is improper heating in the engine, proper fuel ignition causes white smoke. The air and fuel mixture in ratio with high gasoline produces black smoke.

Rough Idling

• If any glow plug burned out, the engine takes time to start since the temperature is reduced, and idle causes white smoke in the exhaust for some time.

Difficult engine start

• Sometimes the engine started with difficulty; that was due to broken glow plugs. If there is not accurate working of glow plugs, the combustion chamber is not heated in cold weather for fuel ignition and starting the engine.

low fuel efficiency

•   Some other factors can affect fuel efficiency, but glow plugs are also an important causes if you are facing fuel economy less than normal results.

Engine Misfiring

• The combustion of a diesel engine needed a good rate of compression, and fuel was required to be added at an accurate time and in the proper amount. that ignites diesel fuel to provide combustion. Misfires result from low fuel quality, compression, and fuel injections. Heating of combustion chambers is due to compression pressure and glow plug heating. That is about 232°C for ignition. If glow plugs are faulty, the engine chamber does not get the required heat.

How many glow plugs are in a car?

• Glow plugs are part of a diesel engine; diesel fuel needs a higher temperature for ignition than petrol-operating vehicles.
• glow plugs preheat air in the cylinder for providing engine starting and accurate temperature. A petrol engine uses spark plugs for ignition.
• Spark plugs produce electric sparks for the ignition of the air-fuel mixture in the engine cylinder. So glow plugs are not used for petrol-operating cars; their working is based on spark plugs for combustion.
• In different diesel-powered vehicles, one glow plug for one cylinder. So a 6-cylinder engine has 6 glow plugs.
• It can be different based on engine design, type, and manufacturer.

How to replace glow plugs

The removal and replacement process of a glow plug is a sensitive process that needs expert services. Follow these points for replacement of glow plugs.

1. First of all, open the bonnet and find the cylinder, open the cylinder, and remove the old glow plugs with the use of a socket wrench.
2. Now install the new plug strongly and tighten with a wrench.
3. Check that it is accurately tightened. For this, follow the car manual.
4. Now reconnect wires that disconnected at starting.
5. Now close the cylinder and bonnet and start the engine for smooth operations.

How Many Glow Plugs Are in a Diesel Engine?

• the glow plugs has two main types, first one goes in cylindr and other in manifold. cylinder glow plugs; there is one plug in one cylinder.
• manifold type, one glow plug used for different cylinders. Numbers of glow plugs in a diesel engine are based on numbers of cylinders. like 6 cylinder engine have in cylindr plugs have 6 plugs

How long will glow plugs last?

• Glow plugs normally work for 80,000 to 100,000 miles; that is based on type and driving style.

How much does it cost to replace a glow plug?

• The average cost for replacement of a glow plug is about £220. This includes components and labor. The final price is based on the the model, working life, manufacturer, and condition of the car. Here we have made a table for the average cost of glow plug replacement for different brands

Car model	Average cost
Audi	£200
BMW	£250
Citroen	£220
Ford	£245
Mercedes	£230
MINI	£210
Nissan	£200
Renaul	£190
Toyota	£180
Vauxhall	£232
Volkswagen	£200
Volvo	£220