GF09.40-P-3002M Actuation Divert Air, Function

GF09.40-P-3002M Actuation Divert Air, Function
- ENGINE 275.950 in MODEL 215, 220
- ENGINE 275.951 in MODEL 230 up to Model Year 8
- ENGINE 275.953 in MODEL 216, 221 up to Model Year 8
- ENGINE 275.954 in MODEL 230 up to Model Year 8
- ENGINE 275.980 in MODEL 215, 220
- ENGINE 275.981 in MODEL 230 up to Model Year 8
- ENGINE 275.982 in MODEL 216, 221 up to Model Year 8
- ENGINE 285.950 in MODEL 240
- ENGINE 285.980 in MODEL 240





12 Intake manifold
22 Vacuum reservoir
128 Check valve (vacuum)
110/4 Deceleration air valve
110a Left turbocharger
110b Right turbocharger
110d Compressor turbine wheel
B37 Accelerator pedal sensor
N3/10 ME-SFI [ME] control unit
Y101 Divert air switchover valve
b to air injection switchover valve
B Test connection for divert air
D Clean air (downstream of air cleaner)
E Charge air





22 Vacuum reservoir





5/2 Charge air cooler, right cylinder bank
B Test connection for divert air

Function
If the engine control unit identifies the transition from load to deceleration operation, the switchover valve deceleration switchover (Y101) is actuated. Through this both deceleration air valves at the turbochargers are discharged with vacuum from the vacuum tank (22). The deceleration air valves open a bypass around the individual compressor turbine wheel, through which the boost pressure is immediately removed. Charger noises (brief howling) during transition into the deceleration mode cannot result from pressure points in the charger.

The turbochargers rotate a little, by means of the inertia of masses of shaft, the compressor and the turbine wheel after start of deceleration and create against the closed throttle valve briefly further boost pressure. This pressure is quickly released through the deceleration air valves.

Without actuation at the switchover valve deceleration switchover the diaphragm chambers of the deceleration air valves are connected with the intake manifold. The deceleration air valves close in load operation through the boost pressure and the spring load. If a deceleration air valve does not close, less boost pressure is released.

In the vacuum tank vacuum is gathered in the suction operation of the engine and in the deceleration. The check valve opens only at vacuum.