(1) Collector for intake air
(2) Resonating pipe
(3) Overshoot pipe
(4) Resonance pipe
DISA actuator motor
(1) DISA actuator motor
(2) Throttle valve
The actuator forms a unit with the drive. The actuator is driven by an electric motor and gearing. The control electronics are integrated in the DISA actuator motor. The DME controls the DISA actuator motor by means of a pulse-modulated signal. There are only 2 possible positions. The actuator can be closed or opened. When activated, the actuator moves the flap to each end position. Depending on the engine concerned, the N52 is fitted with 2 DISA actuator motors, or 1 DISA actuator motor, or without.
How it works
The power and dynamics of an engine depend heavily on the quality of the cylinder filling. The intake air mass oscillates due to the piston motion. These oscillations are overlapped in turn by oscillations from pressure peaks. To guarantee optimum air intake, the N52 engine has a three-stage differentiated air intake system (DISA).
The air intake guide is realized by a switchover mechanism in the inlet pipe with two DISA actuator motors and an overshoot pipe in the intake area. The DISA actuator motors are each driven by an electric motor. The two DISA actuator motors are of different sizes. DISA actuator motor 2 is fitted in the overshoot pipe and DISA actuator motor 1 is fitted in the collector for intake air in front of the resonating pipe.
1st stage - idling/lower engine speed range
At idle speed and in the lower engine speed range, the DISA actuator motors 1 and 2 are closed.
The intake air flows past the throttle valve into the resonance pipe. In the resonance pipe, the intake air mass splits. The air is fed via the collector pipe and resonating pipes into the individual cylinders. In this way, three cylinders are provided with a comparably high air mass.
2nd stage - medium engine speed range
In the medium engine speed range, DISA actuator motor 2 is opened.
In this case, it is assumed that the inlet valves of the first cylinder are just closing. The gas motion creates a pressure peak at the closing inlet valves. This pressure peak is passed on via the resonating and collector pipes to the in next cylinder in the firing order. This improves the filling of the next cylinder to be charged.
3rd stage - upper engine speed range
In the upper engine speed range, both DISA actuator motors are opened.
In this case, it is assumed that the inlet valves of the first cylinder are just closing. The gas motion creates a pressure peak in front of the closing inlet valves. The intake air mass is now fed via the resonating, overshoot and collector pipes.
EDIT: The firing order of the N52B30M1 engine is
1-5-3-6-2-4