Functional Description of EGM
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Status September 2003 (EvoBus-Service / AFT)
Page: 27 of 83
2.2.2
Idling control
Engine idling is controlled by the EGM. Customer Service cannot influence the idling controller – no
adjustment work is required or possible. The target idling speed is dependent on the coolant
temperature.
Idling control: target idling speed
The idling controller operates independently of the engine state – the LLR can operate both in the engine
state "Idling" and in the partial and full-load operating modes. Minor speed dips during load connection
(e.g. when starting off at traffic lights, switching on the air conditioner etc.) and slow adjustment of the
target idling speed compared to the diesel engine are typical for the M 447 hLAG and normal. Poor, rough
idling frequently indicates problems in the ignition system. An increased idling speed frequently indicates
the entrance of unmetered air, which the engine draws past the throttle valve.
LLR - Target idling speed
Speed [rpm] = f(Engine temperature [°C] )
Target idling sp
eed
Engine temperature
