Mono Turbocharger Operation
A = DIRTY AIR; B = CLEAN AIR; C = CHARGE AIR; D = EXHAUST GASES.
| ITEM | DESCRIPTION |
|---|---|
| 1 | Engine |
| 2 | Exhaust system left intake pipe |
| 3 | Primary turbocharger |
| 4 | Left intake grills |
| 5 | Left air cleaner |
| 6 | Left charge air cooler |
| 7 | Charge air shut-off valve |
| 8 | Charge air recirculation solenoid |
| 9 | Right charge air cooler |
| 10 | Right air cleaner |
| 11 | Right intake grills |
| 12 | Electric throttle |
| 13 | Secondary turbocharger |
| 14 | Exhaust system right intake pipe |
| 15 | Turbine shut-off valve |
Fresh air is drawn through the left air cleaner and the MAF (Mass Air Flow) sensor to the primary turbocharger compressor. The compressed air then passes through the charge air coolers and electric throttle to the intake manifolds.
The turbine shut-off valve on the secondary turbocharger is closed and therefore exhaust gases are unable to operate the secondary turbocharger turbine. In this condition all charge air pressure is produced by the primary turbocharger using the exhaust gases from all six cylinders.
If the engine idles for more than 3 minutes, the secondary turbocharger is actuated to keep the turbocharger shaft rotating, to prevent oil from leaking into the turbine housing. This is achieved by periodically opening the turbine intake shut-off valve to operate the turbocharger.