ME-SFI tumble flap switchover function - GF07.61-P-4017G
ENGINE 273 in MODEL 463.202/222/236/237 up to 31.5.12 as of model year 2009/YoM 08
View of the variable intake manifold
Function requirements for the ME-SFI gasoline injection and ignition system (engine electronics) (ME) tumble flap switchover, general points
- Circuit 87M ON (engine control ON)
- Engine running
- No idling
ME-SFI tumble flap switchover, general points
In the variable intake manifold, the tumble flaps in each intake port can be swiveled inward. They can thus reduce the cross-section of the related intake port by about 50%.
The flow rate of the intake air increases and ensures better distribution of the fuel air mixture in the combustion chamber.
The ME-SFI [ME] control unit actuates the tumble flap switchover according to signals from the following sensors:
- Hot film MAF sensor, engine load
- Coolant temperature sensor
- Crankshaft Hall sensor, engine speed
- Left and right position sensor for the intake manifold tumble flap
ME-SFI tumble flap switchover, function sequence
For tumble flap switchover, the ME-SFI [ME] control unit uses a ground signal to actuate the tumble flap switchover valve, depending on engine load, coolant temperature and engine speed.
The tumble flaps are swiveled inward in the following conditions:
- Engine load < 30%
- Engine speed <3000 rpm
- Coolant temperature < 60°C
The tumble flaps are actuated by a vacuum unit. When the switchover valve is actuated, the vacuum unit is charged with vacuum from the vacuum reservoir. This causes the tumble flaps into the intake ports.
In the deenergized state, the vacuum unit is ventilated by the tumble flap switchover valve, and the tumble flaps are swiveled outward by spring force.
The mechanical end positions of the tumble flap spindles are monitored by the ME-SFI [ME] control unit via the LH and RH tumble flap position sensors.
For diagnosis, following an engine start, the tumble flap switchover is actuated briefly to test the actuation and achievement of the end positions.
| Component description for ME-SFI [ME] control unit | N3/10 | GF07.61-P-6000G |