On the N47oL 4-cylinder diesel engine, the swirl flaps are adjusted steplessly with an electrical swirl-flap actuator.
The controllable swirl flaps are located in the charge ports. Depending on the operating range, the swirl flaps are activated with various pulse duty factors. The further the swirl flaps are closed, the more fresh air is taken in exclusively through the swirl port. This increases the swirl of the fresh air that is taken in.
In the lower load and engine speed range, the swirl flaps are variably closed depending on the operating range. The swirl flaps are fully opened under the following conditions:
The position of the swirl flaps is also corrected depending on the ambient pressure. At ambient pressures of less than 880 hPa, the swirl flaps tend to open further.
Fig. 1: sectional view of air collector for intake air with swirl flaps
1 |
swirl flap actuator |
2 |
Adjusting lever for swirl flaps |
3 |
Swirl port |
4 |
Charge port |
5 |
Swirl actuator |
6 |
Connection to throttle valve |
The electrical swirl-flap actuator is activated by the DDE control unit via two signals:
The swirl-flap actuator has an adjustment range of 110°. The adjusting time across the entire adjustment range for opening or closing is approx. 0.1 s.
The position sensor of the swirl-flap actuator is integrated in the swirl-flap actuator. The position sensor is supplied with a voltage of 5 V by the DDE control unit. The signal of the position sensor is an analog voltage signal.
If the swirl-flap actuator is replaced, the following service function must be run before the replacement:
Description and sequence of the adaptation, see corresponding functional description.