Technical data

26
9
VANOS Pressure accumulator
The pressure accumulator is preloaded with
nitrogen. A piston separates the oil chamber
from the gas chamber.
The VANOS operating pressure is 115 bar.
The shut-off valve on the pressure
accumulator is closed when the engine is
turned off. A pressure of 80 bar remains in the
pressure accumulator which is immediately
made available the next time the engine is
started.
3 The repair instructions must be observed
when performing any work on the pressure
accumulator! 1
Oil pumps
The oil pump is driven by the VANOS high
pressure pump in connection with a chain.
The oil pump housing accommodates two oil
pumps. The one is a duocentric pump that
pumps the oil from the front oil sump to the
rear oil sump. The other is a slide-valve type
pump which takes the oil from the rear sump
and conveys it to the oil filter at a variable
pressure of up to 5 bar.
The pump outlet is determined by the
eccentricity of the pendulum-type slide valve.
No oil is delivered when the pump runs
centrally with respect to the rotor as all pump
chambers are the same size.
The slide valve is displaced by an inclined
piston. This piston is in equilibrium between
the piston spring and the engine oil pressure.
The greater the engine oil pressure, the more
the piston is pressed against the spring and
the more the slide valve turns in the direction
of 0 delivery.
18 - Drive of oil pump
19 - Oil pan with oil pump
20 - Duocentric pump
21 - Slide-valve type pump