Lubrication Description (1.4L LUH and LUJ)
General Lubrication Description
Oil is applied under pressure to the crankshaft bearings (6),
connecting rod bearings (7), camshaft bearings (2) and hydraulic
lash adjusters (3). In addition the variable oil pump (9), variable
camshaft phaser (1), and hydraulic chain tensioner (14) are
supplied with pressurized oil. Oil is sucked from the oil pan
through the fixed screen into the variable vane type oil pump. The
pump is integrated in the front cover and directly driven by the
crankshaft. Also integrated into the front cover is a pressure
relieve valve (8) that opens when the oil pressure is too high at a
cold start. When that valve is open some oil flows directly into
the oil pan. Normally the pressurized oil passes into the engine
oil gallery leading through the oil cooler (5) to the oil filter
assembly (4). The oil is cleaned by passing the filter from the
outer to the inner side of the filter. Then the oil flows into the
main oil gallery. A filter by-pass valve in the oil filter ensures
continues oil flow in case the oil filter should be restricted by
more than 1.7 bar. From the oil filter the oil is distributed to
the crankshaft bearings, oil pump displacement control chamber (10)
and cylinder head feed (11). The connecting rod bearings are
supplied by oil flow passages through the crankshaft connecting the
main journals to the rod journals. A groove around each upper main
bearing furnishes oil to the drilled crankshaft passages. In the
cylinder head the oil is distributed to the variable camshaft
phasers, chain tensioner, oil pressure switch (12) and through the
restrictor orifice (13) into the camshaft feed oil gallery. From
there the hydraulic valve lifters and camshaft bearings are
supplied with oil.
Variable Oil Pump Description
The engine is equipped with a variable displacement vane oil
pump. It is indirect regulated by the oil pressure out of the main
oil gallery. The purpose of this indirect regulation is to keep a
defined maximum pressure in the main oil gallery independent of the
individual pressure drop between the pump outlet, the main gallery
inlet, and the various engine components. The purpose of the
variable displacement is to reduce the power consumption of the
pump to reduce the overall fuel consumption of the engine. The oil
flow of a static displacement oil pump is linear to the speed of
the pump. This would lead to a too high oil pressure after a
certain engine speed (ca. 1000 rpm at cold oil temperature, ca.
3000 rpm at hot oil temperatures). To reduce that high oil pressure
normal pumps have a relieve valve: a portion of the pressurized,
already pumped oil is fed back to the intake of the pump. This is
waste of power. The oil flow of a Variable Displacement Vane Pump
(VDVP) as used in Fam 0 Gen 3 is linear to the speed and to the
excentricity of the rotor to the slide. The slide is moveable, so
it is possible to reduce the oil flow for a given speed by reducing
the excentricity. With a lower flow the oil pressure is reduced;
pump oil flow equals now engine oil flow.
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