Audi 4.2-liter V8 FSI, Service Training

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Air Circulation System
20
Air Intake
The intake path of the Audi Q7 is double-chambered and
discharges into a variable inlet manifold made of gravity
die cast aluminum. A Bosch throttle valve module with
a diameter of 82 mm is located upstream of the variable
inlet manifold.
The variable intake manifold is of the two-stage design.
In the lower RPM range, the long intake manifold path is
activated in order to increase torque. In the upper RPM
range, the short intake manifold path is activated. This
position produces an increase in engine power output.
Intake manifold path change-over is map-controlled.
The adjustment is made by the Variable Intake Manifold
Runner Motor V183. No feedback is given on the position
of the variable inlet manifold.
If the intake manifold shutoff is not functioning, exhaust
gas quality is not impaired. In this case, the driver will
notice a loss of power.
Intake Manifold Flaps
As with the variable intake manifold, the intake manifold
flaps in both engine variants are controlled according to
a characteristic map. In both engines the intake manifold
flaps are activated in the lower engine load and RPM
ranges.
They are brought into contact with the port baffles in
the cylinder head and seal the lower part of the intake
port. The aspirated air mass now flows through the
upper section of the intake port and induces a tumbling
charging motion inside the cylinder.
When not activated, the intake manifold flaps are open
and the cross-sectional area of the port is maximized. All
flaps in a cylinder bank are attached to a common shaft.
In the basic engine in the Audi Q7 the intake manifold
flaps are activated via an electrical actuator.
For each cylinder bank, the position of the intake
manifold flaps is monitored by a Hall sensor.
In the high-revving engine, the intake manifold flaps are
activated by a single vacuum actuator per cylinder bank.
In this case, too, the flap position is indicated by means
of Hall sensors.
377_023
Audi Q7 Intake System
Mass Air Flow (MAF) Sensor G70
Throttle Valve Module Variable Inlet Manifold
Mass Air Flow (MAF) Sensor 2 G246
Intake Manifold Flaps