Engine – Cayenne V8
Page 1.22
Oil Supply in the Cylinder Head
Camshaft Control With Valve Lift Control (VarioCam Plus)
The requirements imposed on engine design with regard to higher
performance combined with improved driving comfort, compliance with
emission regulations and reduced fuel consumption give rise to
conflicting design criteria.
The development of the VarioCam Plus was therefore based on the idea
of producing a variable engine, which can be optimized for maximum
performance and also for regular driving in city traffic or on secondary
roads. A control system for the intake camshaft to vary the opening and
closing times in combination with a valve lift system is necessary.
Camshaft Control
Camshaft control on the intake camshaft is based on the principle of a
vane controller. The DME control unit determines the current position of
the camshaft in relation to the crankshaft (actual angle) on the basis of
the speed sensor signal and the Hall sensor signal. The position control
in the control unit receives the desired nominal angle via the
programmed map values (speed, load, engine temperature). A regulator
in the DME control unit activates a solenoid hydraulic valve according to
the desired adjustment when there is a difference between the target
angle and actual angle. The adjustment angle is 50° in relation to the
crankshaft (25° in relation to the camshaft).
1 - Oil supply to the chain tensioner
2 - Camshaft control system
3 - Valve lift control system
4 - Oil supply for valve lift control
5 - Oil supply for turbocharger
6 - Oil intake
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