Engine ventilation
The engine ventilation is pressure-controlled. Depending upon the pressure levels in the intake manifold and the boost pressure, air is discharged either through a 6-channel distributor into the intake tracts or into the fresh-air intake duct on the intake side of the turbocharger (cylinders 4 through 6). The distributor rail is integrated in the cylinder head cover.
| Item | Explanation |
|---|---|
| 1 | Engine ventilation heating |
| 2 | Fresh air pipe before the exhaust turbocharger (cylinders 4 to 6) |
| 3 | Electromotive throttle actuator |
| 4 | Intake silencer |
| 5 | Intake plenum |
| 6 | Engine |
| 7 | Fresh air pipe before the exhaust turbocharger (cylinders 1 to 3) |
| 8 | Exhaust turbocharger |
| 9 | Non-return valve with pressure limitation (for engine ventilation into the inlet ports), integrated in the cylinder head cover |
| 10 | Non-return valve to the fresh air pipe (for engine ventilation) |
Two valves are fitted for engine ventilation.
- Non-return valve with pressure limitation
The non-return valve with pressure limitation regulates the flow depending on the applied intake pipe vacuum and controls the introduction of the blow-by gases into the inlet ports. As of a defined charging pressure, the non-return valve closes with pressure limitation.
- Non-return valve to the fresh air pipe
The 2 fresh air pipes are arranged after the intake muffler. Each of the 2 fresh air pipes connects the air filter to an exhaust turbocharger. In the fresh air pipe, the air cleaned in the air filter is transported to the compressor. As of a defined charging pressure, the prevailing partial vacuum in the fresh air pipe opens the non-return valve. The blow-by gases are vented into the fresh air pipe to the exhaust turbocharger (cylinders 4 to 6).
The ventilation connection to the fresh air pipe has an engine ventilation heating system based on the PTC principle (positive temperature coefficient). The engine ventilation heating is activated via terminal 87.