How Does a Glow Plug Ignitor Work?

Glow plug ignitors heat and help to start a diesel engine.

A glow plug ignitor refers to a device that heats diesel engines to assist in starting them. Glow plugs take the place of spark plugs used in internal combustion engines.

Compression

Diesel engines rely on a compression system to operate as opposed to a combustion system. In diesel compression systems, a piston rises, compressing cylinder air and increasing the level of heat in the engine. In cold weather, this heat dissipates so quickly that the engine cannot start on its own and requires glow plugs to heat each prechamber.

Function

Glow plug ignitors -- thin pieces of metal in the shape of a pencil -- contain heating elements in their tips. The heating element activates via electrical existence and produces light. The heat emitted from the glow plug ignitors enters the cylinders and heats up the engine block.

Pre-Heating Cycle

As the glow plug ignitors heat the engine block, sensors within the engine detect the temperature level and produce a "wait-to-start" light on the operator's dashboard. The glow plug pre-heating cycle typically has a duration of between two and five seconds. When the cycle ends, the "wait-to-start" light switches off, prompting the operator to turn the key to the start position to activate the diesel engine.

References

• CarDictionary.com: Glow Plug
• "Troubleshooting and Repair of Diesel Engines"; Paul Dempsey; 2007

Resources

• "Modern Diesel Technology: Diesel Engines"; Sean Bennett; 2009