23rd June 2024

VAG|AUDI Technical Info

The intake manifolds of both cylinder banks, in VAG’s V6 TDI engine, are fitted with continuously variable swirl flaps. The “swirl flap shaft” is moved by the intake manifold flap motor via a push rod. To do this, the positioning motor is actuated by the engine control unit (ECU). An integrated, in the electronic motor, sensor serves to feed back the current position of the swirl flaps.

Position at low engine speeds

The swirl flaps are closed when the engine is idling and at low engine speeds. This causes a high level of air swirling, which leads to better mixture formation (AFR). The swirl flaps are fully open when the engine is started, in limp-error mode and at full throttle.

Position at high engine speeds

Starting from an engine speed of approx. 1250RPM, the swirl flaps are open continuously. This is resulting in better combustion chamber filling, which is achieved by the increased air throughput. As of an engine speed of approx. 2750RPM, the swirl flaps are fully opened.

Swirl Flaps – macro

Adjustable swirl flaps are molded to a shaft and incorporated into the intake manifold. The flaps are adjusted by the electrical swirl flap adjuster. They enable the airflow to be adjusted to suit engine speed and load. Not only additional power and torque result, but also lower fuel consumption and emissions. The electrical swirl flap adjuster is activated by the engine control unit, which is notified of the momentary position of the swirl flap by a potentiometer integrated in the swirl flap adjuster module. Due to the position of the swirl flaps, the quantity of air sucked into the combustion chamber is adapted to the engine speed.

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