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

GF07.61-P-3028MLK 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 position sensor (L5), motor 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) in the following conditions:
- Engine load >50 % and <90 %
- Engine speed >1750 rpm and <3900 rpm

When starting and at low engine speeds, the changeover flaps are always open.

When the variable intake manifold switchover valve is actuated, the variable intake manifold vacuum unit is charged with vacuum from the vacuum reservoir.
The changeover flaps are then closed off by the variable intake manifold vacuum unit through a linkage.

Sectional view from rear (at cylinder level)

Component Identification:

A pivoting changeover flap is located in the variable intake manifold for each cylinder. If the changeover flaps are closed, the short intake tracts are closed off and the intake air flows through the long intake tracts.
When not actuated, the changeover flaps are opened by spring force, thus opening the short intake tracts.