Intake manifold switchover function - GF07.61-P-3028G

ENGINE 273 in MODEL 463.202/222/236/237 up to 31.5.12 as of model year 2009/YoM 08

Fig 1: Intake Manifold Switchover Function Chart

Courtesy of MERCEDES-BENZ USA

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. 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)

The variable length intake manifold switchover flaps are opened in the following conditions:

Engine load > 50%
Engine speed n > 3500 rpm

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

Fig 2: Identifying Variable Length Intake Manifold Switchover Flap (Opened)

Courtesy of MERCEDES-BENZ USA

Long intake tracts (section in cylinder level)

The variable length intake manifold switchover flaps are closed in the following conditions:

Engine speed n < 3500 rpm

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

Fig 3: Identifying Variable Length Intake Manifold Switchover Flap (Closed) And Tumble Flap

Courtesy of MERCEDES-BENZ USA

Component description for ME-SFI [ME] control unit

N3/10

GF07.61-P-6000G