Crankcase Ventilation System, Function - GF01.20-S-0001TRJ
Engine 274 in model 447.6/7
with code XM0 (Facelift)
Function requirements for crankcase ventilation system, general
- Circuit 87M ON (Engine management ON)
The circuit 87 signal is transmitted by the circuit 87M relay (K40/10kN) via direct line to the ME-SFI [ME] control unit (N3/34).
Crankcase ventilation system, general
The crankcase ventilation system ensures under all operating conditions of the engine that overpressure and excess gases are dissipated from the crankcase and fed back to the engine via the intake air system for combustion. To balance out the pressure ratio, a separate line is attached for engine ventilation (3).
Crankcase ventilation system controlling is dependent on the following components and signals:
- Intake manifold pressure sensor (B28/24), engine load signal
- Accelerator pedal module (B37/4), accelerator pedal position signal
- Signal acquisition and actuation module control unit (SAM) (N10/1), outside temperature from outside temperature sensor (B14)
- Bleed line contact switch (S208), bleed line signal
Front left view of engine
Crankcase ventilation system function sequence
The function sequence of the crankcase ventilation system is described in the following points:
- Function sequence for crankcase ventilation system partial load operation
- Function sequence for crankcase ventilation system wide open throttle operation
Function sequence for crankcase ventilation system partial load operation
In partial-load operation, ventilation is performed to the charge-air distributor starting from the oil separator (2). To do so, the partial load operation crankcase ventilation system valve (Y136) is arranged in the partial-load vent line (A).
The partial load operation crankcase ventilation system valve (Y136) is actuated in deceleration mode by the ME-SFI [ME] control unit and closes the partial-load vent line (A) from the crankcase to the charge air distributor.
The inflow of exhaust from the crankcase during the mixture adaptation and disruptive background noise are thus avoided. If there is no actuation by the ME-SFI [ME] control unit, the partial load operation crankcase ventilation system valve (Y136) is permanently open.
Function sequence for crankcase ventilation system wide open throttle operation
In wide open throttle operation, ventilation is performed starting from the oil separator (2) to the air intake pipe.
The wide open throttle operation vent line heater element (B) is located in the vent line heater element wide open throttle operation (B157) and prevents freezing of the ventilation system. For this purpose, it is directly actuated by the ME-SFI [ME] control unit once outside temperatures below 7°C are measured.
| Function schematic for crankcase ventilation system | PE01.20-S-2500-97TRH | ||
| Overview of system components for gasoline injection and ignition system with direct injection | GF07.70-S-9998TRJ |