On a diesel engine, it is crucial that during the phase of compression in the combustion chamber the temperature reaches 257°C and a pressure between 30 and 55 bars, so that the diesel can auto-ignite when injected.
A cold engine makes it impossible to quickly reach this temperature, so a hot spot is generated in the combustion chamber to raise the temperature in the shortest period of time possible. This is the role of the glow plug.
The glow plug is an electric resistance appliance, when it encounters a current its resistance generates heat in less than 2 seconds, using the same principle as a filament bulb.
122 part numbers cover 92% of the European car range with both technologies: 100% Fero Cobalt & Green technology and “ISS” instant start system for recent applications and direct injection.
Valeo spark plugs fulfil OE quality & manufacturing processes with a simple range: one application, one choice.
Note that spark plugs are to be changed every 50,000 to 80,000 kms (30,000 to 50,000 miles)