GF07.61-P-3028G Intake Manifold Switchover Function

GF07.61-P-3028G Intake Manifold Switchover Function
ENGINE 273 in MODEL 463.202 /222 /236 /237 up to 31.5.12
- as of model year 2009
/YoM 08





B2/5 Hot film mass air flow sensor
B70 Crankshaft Hall sensor
N3/10 ME-SFI [ME] control unit
Y22/6 Variable intake manifold switchover valve

Function requirements for intake manifold switchover, general
^ 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. This optimizes the engine torque.

The ME-SFI [ME] control unit actuates the intake manifold switchover according to signals from the following sensors:
- Hot film MAF sensor, engine load
- Crankshaft Hall sensor, engine speed

Intake manifold switchover function sequence
For intake manifold switchover, the ME-SFI [ME] control unit uses a ground signal to actuate the variable intake manifold switchover valve, according to engine load and engine speed.

The variable length intake manifold switchover flaps of a cylinder bank are linked to each other by a spindle and are each actuated by a vacuum unit.
The vacuum unit is interconnected over hose lines with the intake manifold switchover valve.

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 air is admitted through the long intake tract.





Short intake tracts (section in cylinder level)

1 Variable length intake manifold switchover flap (opened)

The variable length intake manifold switchover flaps are opened in the following conditions:
- Engine load greater than 50%
- Engine speed n greater than 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)

1 Variable length intake manifold switchover flap (closed)
2 Tumble flap

The variable length intake manifold switchover flaps are closed in the following conditions:
- Engine speed n less than 3500 rpm

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