Exhaust Gas Aftertreatment - Mercedes-Benz OM 457 LA Operating Instructions Manual

Example: drive control unit (ADM)
The drive control unit (ADM) has many func-
tions:
Calculation of torque demand
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The drive control unit (ADM) registers the
driver's requirements. For example, the
position of the accelerator is detected by
the drive control unit (ADM). A torque
requirement is calculated from that and
sent to the engine management control
module (MR) via the CAN connection.
In doing so, information and limitations
from optionally connected control units
such as the gearbox control, retarder con-
trol, ABS and ASR are taken into account.
Output of displays and indicator signals
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which are displayed in the instrument clus-
ter.
Monitoring of coolant level, charge current
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and air filter, for example
Legal speed limitation
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Evaluation of start request
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The engine starting process is initiated
once a corresponding start request is pres-
ent (ignition lock or external engine start/
engine stop button).
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BlueTec

exhaust gas aftertreatment

Exhaust gas aftertreatment control
unit (on the frame)
Exhaust gas aftertreatment control unit
The exhaust gas aftertreatment control unit
reads signals and transmits them via the CAN
line to the engine management (MR) control
unit.
The following signals are read:
temperature sensor upstream of the SCR
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catalytic converter
temperature sensor downstream of the
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SCR catalytic converter
NOx sensor downstream of the SCR cata-
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lytic converter
pressure and temperature sensor for the
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fluid level and temperature in the AdBlue
DEF tank
sensor for humidity and intake air temper-
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ature
If the electronic engine management control
detects a fault, the fault code is stored in the
control units.
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BlueTec exhaust gas aftertreatment
The exhaust gas aftertreatment system is
activated immediately after the engine is star-
ted and remains activated during engine
operation. It ensures that the pollutant emis-
sions in the exhaust gas are reduced to the
limits stipulated in the emissions standard.
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