Oil Pump - Mercedes-Benz OM 651 Service Manual

Oil pump

Oil pump
The oil pump is volume-controlled at the clean oil side
and has a rotary vane design. The control pressure is
4.7 bar.
The oil pump is driven by the gear drive and is
equipped with an integrated pressure limiting valve
which limits the oil pressure to a maximum of 10 bar.
As soon as the engine is started, the engine oil is
drawn in via the intake line with integrated prefilter on
the oil suction pipe and pumped to the oil filter module
with integrated oil-water heat exchanger via the pres-
sure line.
During the cold-start phase of engine operation, the
oil-water heat exchanger ensures that the oil is heated
up more quickly and in the warm-up phase it ensures
that the engine oil is cooled adequately. If the oil flow
is insufficient, the oil can be directed past the oil-
water heat exchanger via the bypass valve installed in
parallel. Only after this does the engine oil enter the oil
filter unit. The oil then flows from outside to inside and
is cleaned in the process. If the flow is insufficient, e.g.
due to a high level of contamination, the oil filter
bypass valve installed in parallel routes the oil flow
around the oil filter.
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Introduction of New Generation of 4-Cylinder Inline Engines, OM 651
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– This printout will not be recorded by the update service. Status: 09 / 2008 –
Oil spray nozzles
The oil spray nozzles and the associated oil feed for
piston crown cooling are actively shut off by the
shutoff valve of the oil spray nozzles. The oil spray
nozzles are shut off by the CDI control unit in the post-
start phase under the following conditions:
• Engine oil temperature greater than -10 °C
And:
• The max. shutoff duration (depending on intake air
and engine oil temperature) has not yet been
reached
Or:
• The engine speed or the injection quantity has not
yet reached a specified limit value
If the oil spray nozzles are ever switched on, they are
no longer shut off for as long as the engine is running.
Cross-section of oil pump