CDI starting function

L15.20-0003-06

A1e16 Preglow indicator light

B11/4 Coolant temperature sensor

N3/9 CR control module

N14/2 Glow output stage

N14/2x1 Plug connection of glow output stage

Control line to CR control module

N14/2x2 Plug connection of glow output stage to the glow plugs

N14/2x3 Plug connection of glow output stage battery positive circuit 30

R9 Glow plugs

S2 Starter switch

Key positions:

0 The key can be withdrawn only in position 0

1 The majority of electrical consumers can be switched on

2 Preglowing and driving position

3 Start position

Function

The preglow operation begins in the key position "Ignition on". The preglow time is calculated in line with the coolant temperature by the CR control module (N3/9). The start operation can be initiated as soon as the preglow indicator light goes out as the glow pin plugs have become hot enough. Startglowing is initiated when the ignition key is turned on into position 3. The glow output stage (N14/2) is supplied with a signal by the C'R control module (N3/9) to indicate that the engine is being started, the glow plugs (R9) continue to be supplied with voltage.

In the subsequent start phase injected fuel droplets vaporize and ignite in contact with the compressed and hot air. The combustion process is thus initiated. During the start operation the injected quantity is calculated in line with the temperature and engine speed.The driver is not able to influence the quantity of fuel injected.

Afterglowing is activated when the starter release speed is reached.

Afterglowing after completion of engine start contributes to smooth engine running at high and low revs in the warming-up phase free of misfiring and thus with a low level of smoke in the exhaust, and reduces the combustion noises. The afterglow period is dependent on the coolant temperature.

Should the engine start operation not be possible, a safety shutoff of the glow plugs prevents the battery being discharged.

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Component or cable defects in the preglow system are indicated by the preglow indicator light and stored in the CDI control module.