Engine Cooling Thermal Management, Function; Electromagnetic Coolant Pump Control - Mercedes-Benz OM 471 Introduction Into Service Manual

GF20.00>W>0003H
MODEL 963 with CODE (M7T) Coolant pump, controlled
A3 Drive control (CPC) control unit
A4 Engine management control unit
(MCM)
A54 Lower radiator shutters controller
unit
A55 Upper radiator shutters controller
unit
B640 Coolant pump rpm sensor
CAN 4 Drive train CAN
LIN 5 Radiator shutters LIN
Y616 Fan clutch solenoid valve
Y616b1 Fan rpm sensor
Y631 Coolant pump solenoid valve
Z4 Drive CAN bus star point
a Coolant pump rpm, signal
b Coolant pump, actuation
c Fan clutch rpm, signal
d Fan clutch, actuation
e Coolant temperature, signal
f Charge air temperature, signal
g Engine speed, signal
General information
The engine cooling thermal management optimizes the engine's
efficiency while also reducing fuel consumption. This is achieved
by the targeted and demand>controlled actuation of the
following components:
f Circulation pump
f Fan clutch
Regulation of the coolant pump enables the coolant flow rate
through the engine to be reduced to the amount required for
each operating condition. The engine radiator's cooling air flow
rate is also regulated by the fan clutch as a function of the
operating condition. Apart from this, the engine cooling thermal
management in vehicles with code (M7K) Radiator shutters has a
cooling air control, which governs the vehicle's aerodynamics
depending on the coolant temperature.
The cooling air control is implemented by actuating the following
components:
f Lower radiator shutters controller unit (A54)
f Upper radiator shutters controller unit (A55)
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i Introduction of engine OM 471 and exhaust aftertreatment > 09/2011 >

Engine cooling thermal management, function

h Lower radiator shutters controller
unit (A54), actuation *
i Upper radiator shutters controller
unit (A55), actuation *
j Lower radiator shutters controller
unit (A54), status *
– This printout will not be recorded by the update service. Status: 09 / 2011 –
k Upper radiator shutters controller
unit (A55), status *
l Secondary water retarder, status
* With code (M7K) Radiator shutters

Electromagnetic coolant pump control

The electromagnetic coolant pump delivery rate can be
continuously varied through the integrated electromagnetic
viscous coupling. The electromagnetic viscous coupling is actuated
by the engine management (MCM) control unit (A4) through a
pulse width modulated signal (PWM signal). The engine
management (MCM) control unit (A4) evaluates the following
information for this:
f Coolant temperature
Engine speed
f
f Engine load status
f Compressor operating condition (active/idle)
f Secondary water retarder operating condition
(with code (B3H) Secondary water retarder)
Depending on the listed information, the engine management
(MCM) control unit (A4) calculates the corresponding set value for
actuation of the viscous coupling.
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Functions
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