Description of engine OM 607
Drive
59
b
Introduction of the New A-Class, Model Series 176
Engine oil fill level sensor
The OM 607 engine is equipped with an engine oil
fill level sensor in the front of the engine oil pan. It
measures the current oil level in the oil pan using a
hot wire.
The measuring principle of the fill level sensor is
based on measuring the voltage U
1
and U
2
at the
terminals of the sensor within a specified period of
time. The sensor consists of a hot wire which is
immersed in the oil. The oil level can be calculated
from voltage U
1
and U
2
and the battery voltage V
bat
.
Current only flows through the sensor for the dura-
tion of the measurement.
For a time period of t_1=0.875 s a constant current
of I_TP=210.5 mA passes through a hot wire
thereby heating it up.
The voltage applied to the connections is measured
at the start of current flow (U
1
) and after a time
period of t_1 (U
2
). To ensure that the current flow is
constant the measuring points have to be adapted
accordingly, cf. dotted lines.
The difference in the two voltage values determines
how much of the hot wire is immersed in oil.
To ensure that conditions are stable, the supply
voltage (V
bat
) is recorded at each of the measuring
points, it will not be directly incorporated into the
calculation however.
The measurement will be conducted once as of
circuit 15 (ignition ON) and at engine OFF. If the
engine is started before the measurement has run
its course, the measurement will be aborted.
P18.40-2402-00
B40/6 Engine oil fill level sensor
P18.40-2404-00
Fill level sensor measuring principle
1 Higher oil level
2 Lower oil level
t Time
U Voltage
U
1
Start of voltage measurement
U
2
End of voltage measurement
U Voltage difference
– This printout will not be recorded by the update service. Status: 06 / 2012 –
