Mercedes-Benz OM 471 Introduction Into Service Manual page 138

GF49.20>W>3003H
ENGINES 471.9 in MODEL 963, 964 with CODE (M5Z) Engine version Euro VI
Location
1 Exhaust aftertreatment unit:
B67 Exhaust temperature sensor
upstream of diesel oxidation
catalytic converter
Task
Via the exhaust temperature sensor
upstream of the diesel oxidation catalytic
converter (B67), the exhaust aftertreatment
control unit (ACM) (A60) records the
temperature of the exhaust flow in the
deflection chamber upstream of the diesel
oxidation catalytic converter (DOC).
Design
The sensor consists of a stainless steel housing. The housing
contains a measuring element, a PTC resistor.PTC stands for
"Positive Temperature Coefficient" and means that the electrical
resistance increases as the temperature increases.
i Introduction of engine OM 471 and exhaust aftertreatment > 09/2011 >
Exhaust temperature sensor upstream of diesel oxidation catalytic converter,
component description
– This printout will not be recorded by the update service. Status: 09 / 2011 –
System components
Function
Depending on its temperature, the gas flowing past the probe
influences the measuring element inside, and makes its electrical
resistance change.
Since the sensor has a constant measuring current flowing
through it, the resistance change causes a voltage drop, via which
the exhaust aftertreatment control unit (ACM) (A60) can work out
the associated temperature value.
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