Mercedes-Benz OM 651 Service Manual page 28

Boost pressure control during wide open throttle operation between 1,200 and 2,800 rpm
As of an engine speed of 1,200 rpm during wide open
throttle operation, the boost pressure control flap
(LRK) is opened in the working range (cross-section of
opening) of 5% to 95% depending on the boost pres-
sure required.
As the cross-section of the LRK opening increases, the
ND-Lader is continuously engaged and a greater
exhaust volume flows through it. The intake of clean
air is further pre-compressed.
Schematic illustration of boost pressure control during wide open throttle operation between 1,200 and 2,800 rpm
A Intake air
B Exhaust flow
1 High-pressure turbocharger
2 Low-pressure turbocharger
3 Boost pressure control flap (LRK)
– This printout will not be recorded by the update service. Status: 09 / 2008 –
In this state, the two turbochargers work together and
provide the required boost pressure jointly.
The wastegate and charge air bypass flap are closed in
this operating condition.
4 Wastegate
5 Charge air bypass flap
6 Air filter
7 Charge air cooler
8 Throttle valve actuator
9 Intake manifold
Introduction of New Generation of 4-Cylinder Inline Engines, OM 651
Charging
10 Exhaust manifold
11 Exhaust gas recirculation (EGR)
pre-cooler
12 EGR actuator
13 EGR cooler
14 EGR bypass flap
q
27