GF07.61-P-3028MIR Intake Manifold Switchover, Function

GF07.61-P-3028MIR Intake Manifold Switchover, Function
- refinement package
- as of model year 09


Function requirements for intake manifold switchover, general points
^ Circuit 87M ON (engine control ON)
^ Engine running

Intake manifold switchover, general points
The intake manifold switchover is used to switch between the long and short intake tracts. In this way the engine torque is optimized.

The ME-SFI control unit (N3/10) actuates the intake manifold switchover according to the signals from the following sensors:
- Hot film MAF sensor (B2/5), engine load
- Crankshaft Hall sensor (B70), engine speed

Intake manifold switchover function sequence
For the intake manifold switchover, the ME-SFI control unit actuates the variable intake manifold switchover valve (Y22/6) with a ground signal, depending on engine load and engine speed.

Engine 272
The switchover flaps of a cylinder bank are linked to each other by means of a shaft, and each is actuated by a vacuum unit. The vacuum units are linked to the variable intake manifold switchover valve by hose lines.

When the variable intake manifold switchover valve is not actuated, the vacuum units are ventilated and the switchover flaps are opened by spring force.
Air intake takes place over the short intake tracts.

When the variable intake manifold switchover valve is actuated, vacuum is applied to the vacuum units from the vacuum reservoir. This causes the switchover flaps to close, and the air intake is switched to the long intake tracts.

Engine 273
The switchover flaps of each cylinder bank are linked to each other by means of a shaft. The two shafts are joined by a linkage and are actuated together by a vacuum unit.

The vacuum unit is linked to the variable intake manifold switchover valve by a hose line.

When the variable intake manifold switchover valve is not actuated, the vacuum unit is ventilated and the switchover flaps are opened by spring force.
Air intake takes place over the short intake tracts.

When the switchover valve is actuated, the vacuum unit is charged with vacuum from the vacuum reservoir. This causes the switchover flaps to close, and the air intake is switched to the long intake tracts.

Short intake tracts (section in cylinder level)

Component Identification:

The switchover flaps are opened in the following conditions:
- Engine load > 50 %
- Engine speed >3500 rpm

Air intake takes place over the short intake tracts. In this way an increase in engine torque and output is achieved.

Long intake tracts (section in cylinder level)

Component Identification:

The switchover flaps are closed in the following conditions:
- Engine speed <3500 rpm

Air intake takes place over the long intake tracts. In this way an increase in engine torque and output is achieved.