Boost Mode
As the pressure in the intake air manifold increases in boost mode, blow-by gasses can no longer be introduced via the passages in the cylinder head, otherwise, the boost pressure could enter the crankcase. A non-return valve (15) in the blow-by channel within the cylinder head cover closes the connection (16) to the intake air manifold. This protects the crankcase from excess pressure.
The increased demand for fresh air creates a vacuum in the clean air pipe between the turbocharger and intake silencer. This vacuum is sufficient to open the non-return valve (12) and draw the blow-by gasses via the pressure control valve.
INDEX EXPLANATION CHART
| Index | Explanation |
|---|---|
| A | Excess pressure |
| B | Vacuum |
| C | Exhaust gas |
| D | Oil |
| E | Blow-by gas |
| 1 | Air cleaner |
| 2 | Intake manifold |
| 3 | Impact plates |
| 4 | Oil return channel |
| 5 | Crankcase |
| 6 | Oil sump |
| 7 | Oil return channel |
| 8 | Exhaust turbocharger |
| 9 | Oil drain valve |
| 10 | Charge air intake line |
| 11 | Hose to charge air intake line |
| 12 | Non-return valve |
| 13 | Pressure regulating valve |
| 14 | Throttle valve |
| 15 | Non-return valve |
| 16 | Passages in cylinder head and cylinder head cover |
NOTE:
If a customer complains about high oil consumption and oil is discovered in the turbocharger, it should not be immediately assumed that the turbocharger is defective. If the oil is present in the fresh air pipe (before the turbocharger) then the entire engine should be checked.