CDI starting, function

Function requirements, general

 "Circuit 50 ON"

 "Enable" from the drive authorization system stage 3 (DAS 3)

Synchronization of the injection sequence

To assign the injection sequence correctly to the cylinder concerned, the sequence is synchronized at the first revolutions of the engine. To do this the CDI control unit (N3/21) needs the signals from rpm sensor (B6/19) and from the crankshaft position sensor (L5/7). The CDI control unit evaluates the inductive signal from the crankshaft position sensor and the Hall signal from the rpm sensor uses both signals to calculate when cylinder 1 reaches TDC.

 If the signal of the rpm sensor is missing for an engine start, the engine does not start.

Common rail diesel injection (CDI) starting, general points

The function starter CDI controls the following function sequences during start up over the CDI control unit which are described in separate documents:

 Starter control

 Preglowing

 Start-up glowing

 Afterglowing

 Start quantity control