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.