Variable Induction Control Actuator: Description and Operation

Swirl Flap Actuator

Swirl flap actuator
The swirl-flap actuator is secured to the intake plenum.
The swirl flaps are continuously adjusted by an electrical swirl-flap actuator. The controllable swirl flaps are located in the swirl ports. Depending on the operating range, the swirl flaps are activated with different duty cycles. The further the swirl flaps are closed, the more fresh air is drawn in exclusively through the swirl port. This increases the swirl of the drawn-in fresh air.

Functional description
In the bottom load and engine speed range the swirl flaps are closed variably according to the operating range. In the following conditions the swirl flaps are fully open:
- Engine speed higher than 2250 1 rpm
- Fuel injection rate greater than 30 mg/stroke
The position of the swirl flaps is also corrected dependent on the ambient pressure. At ambient pressures less than 880 hPa the swirl flaps are opened further proportionally.







The swirl-flap actuator has an adjustment range of 110°. The adjustment time for opening or closing over the entire adjustment range is approx. 0.1 seconds.

Structure and inner electrical connection
The servomotor for swirl flap adjustment is a direct current motor. The position sensor is a hall effect sensor. The hall effect sensor determines the revolutions of the servomotor. This is used to calculate the position of the swirl flaps.







Schematic overview and setpoint values
The position sensor for the swirl flaps is supplied with 5 volts and ground by the DDE.
A bridge circuit (H bridge) is used to activate the servomotor. This permits activation of the servomotor in the opposite direction. The bridge circuit is monitored diagnostically. H-bridge designates an electrical gearshift with 5 shift elements in the shape of a capital H for shifting between.







Please note the following setpoint values for the swirl-flap actuator:

Size Value
Servomotor supply voltage 12 Volts

Activation frequency 1300 Hz
for servomotor

Power consumption of 1.3 A
servomotor

Supply voltage for swirl flaps 4.8 to 5.2 V
position sensor

Power consumption of swirl 16 mA
flaps position sensor

Temperature range of swirl -40 °C to 130 °C
flaps position sensor
and servomotor

Diagnosis instructions

Failure of the component

If the position sensor fails, the following behavior is to be expected:
- Fault entry in the engine control unit
- Emergency operation with substitute value

If the servomotor fails, the following behavior is to be expected:
- Fault entry in the engine control unit
- Mechanical emergency running position of the swirl flap

General notes
If the swirl-flap actuator is renewed, the following service function must be completed before renewal:
- Adaptation of swirl-flap actuator

We can assume no liability for printing errors or inaccuracies in this document and reserve the right to introduce technical modifications at any time.