Oil Pressure Sensor, Description Of Components - Mercedes-Benz OM 471 Introduction Into Service Manual

System components
GF18.40>W>2010H
ENGINE 471.9 in MODEL 963
Location
B604 Oil pressure sensor
The oil pressure sensor (B604) is screwed on
below the coolant pump into the crankcase.
Task
The oil pressure sensor (B604) enables the
engine management (MCM) control unit
(A4) to determine the current engine oil
pressure.
Design
1 Sensor element
2 Sensor membrane
3 Hybrid element
B604 Oil pressure sensor
Function
The engine oil pressure operates on the sensor element (1) of the
hybrid element (3) and distorts the sensor membrane (2).
There are four pressure>dependent resistances (strain measuring
resistors) on the sensor membrane (2). Its bridge circuit is supplied
with voltage by an electronic analysis system which also serves for
signal amplification and signal correction. The electronic analysis
system is powered by the engine management (MCM) control unit
(A4) with 5 V direct voltage.
The resistors in the sensor membrane (2) are arranged in such a
way that on deforming the sensor membrane (2) two resistors are
clinched and two resistors elongated.
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Oil pressure sensor, description of components

– This printout will not be recorded by the update service. Status: 09 / 2011 –
Contraction and elongation changes the electrical resistance of
the resistors which in turn has effects upon the measurement
voltage, which is being applied to the electronic analysis system.
The electronic analysis system amplifies the measurement voltage,
compensating for possible temperature fluctuations or balancing
out possible manufacturing tolerances on the resistances and
passes on the cleared out measurement voltage to the engine
management (MCM) control unit (A4) which uses it to derive the
current engine oil pressure.
20.7.11
W18.40>1034>06
W18.40>1029>01