Determination Of The Coolant Temperature, Function - Mercedes-Benz OM 471 Introduction Into Service Manual

GF07.16>W>4012H
ENGINES 471.9 in MODEL 963
Shown code (M5Z) Engine version Euro VI
A4 Engine management control unit (MCM)
B606 Exhaust coolant temperature sensor
B607 Intake coolant temperature sensor
CAN 4 Drive train CAN
General
The coolant temperature which is required for a number of
factors, including fan regulation or computation of the actuation
begin of fuel injectors, is determined by the engine management
(MCM) control unit (A4).
For fan regulation the engine management (MCM) control unit
(A4) uses measurements made by the coolant intake temperature
sensor (B607) and the coolant outlet temperature sensor (B606).
In order to determine the actuation begin as well as the actuation
period (=injection quantity) of the fuel injectors, the engine
management (MCM) control unit (A4) exclusively uses
measurements from the coolant outlet temperature sensor
(B606).
Component description for engine
management (MCM) control unit
Component description for exhaust
coolant temperature sensor
Component description for intake coolant
temperature sensor
i Introduction of engine OM 471 and exhaust aftertreatment > 09/2011 >

Determination of the coolant temperature, function

– This printout will not be recorded by the update service. Status: 09 / 2011 –
Function
Both sensors, the intake coolant temperature sensor (B607) and
the exhaust temperature sensor in the charge air temperature and
boost pressure combination sensor (B606), are fitted with a
temperature>dependent resistance with a negative temperature
coefficient (NTC) > that is an electrical resistance which reduces as
the temperature increases.
The voltage applied to the engine management (MCM) control
unit changes (A4) according to the temperature of the coolant at
the inlet coolant temperature sensor (B607) or outlet sensor
(B606) the inlet or outlet coolant temperature can be determined
based on its level.
If one of the sensors fails the engine management (MCM) control
unit (A4) continues to operate with substitute values.
This allows the engine to be started even under unfavorable
conditions and for the vehicle to continue to be driven.
i The engine management (MCM) control unit (A4) will limit the
specified engine torque to protect the engine from overheating if
the coolant temperature reaches an impermissibly high value.
A4
B606
B607
Functions
2.8.11
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