During the cold season, diesel engines do not always start as desired. The arising heat is often insufficient for starting the engine on its own . Therefore, the necessary heat in the combustion chambers is missing. Heat losses through the cold cylinders and the air intake impede the self-ignition. The diesel engine does not reach the necessary temperatures without the addition of heat.

The function of glow plugs

The central function of glow plugs is to provide additional energy for the start. Glow plugs from NGK are the required energy source. Before the start of the engine, the glow plug is energised and the glow tube heats up to more than 800 °C. This heat improves the engine's ability to cold-start considerably. The glow plug's heat development also optimises the combustion, so that the development of smoke and other emissions is reduced.

Installation position in the engine

Glow plugs are installed in the cylinder head. The glow rod extends into the hot zone and/or the precombustion chambers. However, the glow rod should be positioned exactly at the edge of the mixture. In this way it can provide the heat exactly where it is needed. However, it may in no case extend too far into the combustion chamber, because the preparation of the fuel and thus the formation of a ignitable fuel-air mixture would not be guaranteed.

Related topics

  • Functional principle of a diesel engine: Unlike the petrol engine, the diesel engine is a self-igniter. It requires the aid of a glow plug to ignite the mixture.
  • Pre-glowing: For a reliable cold start, even with low outside temperatures, diesel engines depend on the support of glow plugs.