After six years of development Audi has revealed the Audi Valvelift System (AVS). Now available on the direct-injection 2.8 and 3.2-liter V6-FSI engines, the system takes variable valve timing to the next level resulting in smooth power build-up, spontaneous throttle response and most importantly, reduced fuel consumption by up to seven percent. Based on the existing variable valve time which permits the valve opening and closing times to be varied, the Audi valvelift system now achieves the next step – variable control of the valve lift, thus influencing the cross-section of the intake duct. For example, under partial engine load, variable valve lift can be 2.0 mm or 5.7 mm. However, under heavy load conditions the inlet valves can lift completely open to 11.0 mm – ideal for high charge volumes and flow speeds in the combustion chamber. The ability to asymmetrically control valve lift causes the charge air to flow into the combustion chamber spirally and cylindrically, also known as “drumble”. Ultimately, the aim is to open and close the valves in such a way that the correct charge of air is always drawn into the cylinders. With an operational range of 700 to 4000rpm the greatest potential for fuel savings is achieved at constant speeds in the mid-range, however, the AVS is capable of handling up to 7000rpm. Future development of AVS will include the complete shutdown of individual cylinders.
