The glow system should, especially for the side combustion chamber system, from around +20°C, but also with direct injection
from around -5°C (cold start), heat up the combustion chamber, influencing positively the starting of the engine, and thus noise and emissions.
How it works
Nowadays, the glow plugs remain operative after the cold start, thus, the name 'preglow arrangement' is no longer contemporary.To keep the preglow time for drivers as briefly as possible, for some vehicles, the glow
plugs of the single cylinders are already switched on (0.5 - 2 ohms) when opening the driver's door. The engine can be started when the controlling light ceases.
The glow plugs are switched off if the engine start
does not occur within a certain time. Also, the after-glow time is dependent on the temperature. There is an after-glow, to diminish the loudly 'knock' of the diesel engine in the cold run. This originates from oversized
ignition delay (time between injection beginning and inflammation).
Especially truck engines partly renounce a glow equipment or have a flaming start equipment. A small quantity of diesel is burned constantly in
the suction part, warming up the sucked in air.