GF07.61-P-4017MIK ME Tumble Flap Switchover Function

GF07.61-P-4017MIK ME Tumble Flap Switchover Function
- refinement package
- as of model year 09

Component Identification:

Function requirements for tumble flap switchover, general points
^ Circuit 87M ON (engine control ON)
^ Engine running
^ NO IDLING

Tumble flap switchover, general points
In the variable intake manifold, the tumble flaps in each intake port can be swiveled inward. In this way the cross-section of the respective intake port is reduced 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 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
- Coolant temperature sensor (B11/4)
- Crankshaft Hall sensor (B70), motor speed
- LH and RH intake manifold tumble flap position sensors (B28/9, B28/10)

Tumble flap switchover function sequence
For the tumble flap switchover, the ME-SFI control unit uses a ground signal to actuate the tumble flap switchover valve (Y22/9), 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.

When deenergized, the vacuum unit is ventilated through the tumble flap switchover valve and the tumble flaps are swiveled out by spring force.

The mechanical end positions of the tumble flap spindles are monitored by the ME-SFI control unit through 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.