Mercedes-Benz OM 904-926 LA BlueTec, Руководство по эксплуатации

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Electronic drive control
The engine has a fully electronic control sys-
tem which, along with the engine and its asso-
ciated sensors, consists of the following com-
ponents:
R
the engine control unit (MR) and
R
the drive control unit (FR) and/or other
vehicle-specific control units, e.g. ADM
R
SCR frame module (only for engines with
BlueTec
®
exhaust gas aftertreatment)
The control units are interconnected by a
CAN line (Controller Area Network line) which
facilitates the exchange of all necessary data.
In addition to the engine and the BlueTec
®
exhaust gas aftertreatment, the electronic
engine control also monitors itself. Depend-
ing on the malfunctions/failures that occur,
a safety and emergency mode (
Y
page 8) may
be automatically selected.
For vehicle engines, the electronic engine
control only allows the engine to be started
when the transmission is in neutral.
Engine control unit (engine resident)
The engine control unit is on the left side of
the engine.
Example: OM 926 LA engine control unit
The engine control unit processes values
from the FR (drive control) unit and the ADM.
These are, for example, the value from the
position sensor (accelerator pedal), the
engine brake or engine start/stop, etc.
These values are analysed together with data
from the engine sensors. They are compared
with the charts or characteristic curves
stored in the engine control unit.
Data from the sensors derives from, e.g.:
R
charge-air pressure and charge-air temper-
ature
R
coolant temperature
R
fuel temperature
R
oil pressure
Start of injection, injection period and injec-
tion quantity are calculated on this basis and
the unit pump is controlled via the solenoid
valve accordingly.
If BlueTec
®
exhaust gas aftertreatment is
available, the associated sensors are also
analysed and the AdBlue
®
/DEF dosage is
controlled.
i To obtain a replacement engine control
unit, you will require all the data on the
control unit type plate.
Control unit type plate
:
Data record
;
Certification no.
=
Engine number
?
Equipment code
22
General information
At a glance