GF07.09-D-0800HD | Engine vacuum system - as-built configuration | 22.6.11 |
ENGINES 651.955 /956 /957 in MODEL 906
ENGINES 651.940 in MODEL 639.6 /70
with CODE (XZ1) Model generation 1
with CODE (MZ0) BlueEFFICIENCY
D07.09-0002-06
Schematic representation of the vacuum system, engine 651.940/956
7 Cylinder head
8 Vacuum pump
9 Exhaust gas recirculation cooler bypass vacuum unit
a Ambient pressure
Y27/16 Exhaust gas recirculation cooling solenoid valve
Function of engine 651.940/956
The vacuum pump is driven by the crankshaft via a gear drive and generates the required vacuum. The exhaust gas recirculation cooling solenoid valve is connected with the vacuum pump over vacuum hoses and lines.
If the exhaust gas recirculation cooling solenoid valve is actuated dependent on a characteristic map by means of a pulse width modulation (PWM) signal then the vacuum acts on the exhaust gas recirculation cooler bypass vacuum unit and opens the bypass duct over which the part of the exhaust is passed by the exhaust gas recirculation cooler.
D07.09-0003-09
Schematic representation of the vacuum system, engine 651.955/957
7 Cylinder head
8 Vacuum pump
9 Exhaust gas recirculation cooler bypass vacuum unit
10 Boost pressure control flap vacuum unit
Y27/16 Exhaust gas recirculation cooling solenoid valve
Y77/7 Waste gate pressure transducer
Y93/1 Boost pressure control flap pressure transducer
11 Wastegate vacuum unit
12 Vacuum reservoir
14 Air admission filter
a Ambient pressure
Function of engine 651.955/957
The vacuum pump is driven by the crankshaft via a gear drive and generates the required vacuum. The vacuum pump is connected to the vacuum reservoir via a vacuum hose.
The vacuum reservoir is connected to the following components via vacuum hoses and lines:
- Pressure transducer wastegate
- Boost pressure control flap pressure transducer
- Exhaust gas recirculation cooling solenoid valve
If the wastegate pressure transducer is actuated dependent on a characteristic map by means of a pulse width modulation (PWM) signal then vacuum acts on the wastegate vacuum unit and opens the wastegate in the low-pressure turbocharger continuously so that part of the exhaust flow bypasses the low-pressure turbocharger and is fed into the exhaust system.
If the boost pressure control flap pressure transducer is actuated by means of a PWM signal according to a performance map, the vacuum acts on the boost pressure control flap vacuum unit and opens the boost pressure control flap in the high-pressure turbocharger steplessly so that part of the exhaust flow bypasses the high-pressure turbocharger and is fed to the low-pressure turbocharger.
If the exhaust gas recirculation cooling solenoid valve is actuated dependent on a characteristic map by means of a pulse width modulation (PWM) signal then the vacuum acts on the exhaust gas recirculation cooler bypass vacuum unit and opens the bypass duct over which the part of the exhaust is passed by the exhaust gas recirculation cooler.
The 2 pressure transducers are ventilated with ambient pressure via a common vent filter.
Aeration of the exhaust gas recirculation cooling solenoid valve with ambient pressure takes place over an aeration connection with filter directly on the exhaust gas recirculation cooling solenoid valve.