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

ENGINES 272.9 in MODEL 221.0 /1 as of model year 2009/YoM 08

ENGINES 273.9 in MODEL 216.3, 221.0 /1 as of model year 2009/YoM 08

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 (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 [ME] control unit uses a ground signal to actuate the variable intake manifold switchover valve (Y22/6), according to engine load and engine speed.

The switchover flaps for one cylinder bank are linked together by a spindle and (on engine 272) are each actuated by a separate vacuum unit.

On engine 273, the two spindles are connected by a linkage and are actuated together by one vacuum unit.

The vacuum unit or vacuum units are connected by hose lines to the variable intake manifold switchover valve.

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, the vacuum units are 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)

Fig 1: Identifying Intake Manifold Switchover Flap Opened (Short Intake Tracts)

Courtesy of MERCEDES-BENZ USA

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

Relative engine load <50 %
Engine RPM <2000 RPM or >3500 RPM

Air intake takes place over the short intake tracts. This increases engine torque and engine output.

Long intake tracts (section in cylinder level)

Fig 2: Identifying Intake Manifold Switchover Flap Closed (Long Intake Tracts)

Courtesy of MERCEDES-BENZ USA

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

Relative engine load >80 %
Engine speed approx. 2000 to 3500 RPM

Air intake takes place over the long intake tracts. This increases engine torque and engine output.

	Electrical function schematic for intake manifold switchover	Model 216		PE07.61-P-2781-97CAB
	Component description for ME-SFI [ME] control unit	N3/10	Engine 273	GF07.61-P-6000MLS