Variable Induction System: Description and Operation

Variable intake manifold

Like in the previous model, a variable intake manifold is installed in the new Cayenne V6. The intake system with variable intake manifold combines the advantage of a long intake manifold - higher torque at low rpm - with that of a short manifold, namely high specific output in the upper rpm range. For this purpose, the resonance tube uses the air mass oscillations in the intake tract, dependent on the engine speed, to achieve better volumetric efficiency of the engine. Depending on the position of the intake manifold flap, this permits realization of a high torque curve in conjunction with the optimised intake duct geometry.

The DME control unit controls the electro-pneumatic switching valve, which switches a vacuum to the diaphragm cell in order to switch to the long intake manifold length at low engine speeds. Switching to the short intake manifold takes place as from 4,200 rpm.