the upper and lower core, through the connecting piece and
towards the heat exchanger for the heater.

Outlet to the
connecting piece

Upper coolant jacket core

Lower coolant
jacket core

S514_047

Connecting piece for
coolant hoses

Defined cross section

Upper water jacket

Cylinder head outlet

Lower water jacket in proximity
to the combustion chamber plate

608_043

Legend for illustration on page 18:
1
2
3
4
5
6
7
8
9
17

Fuel Pressure Regulator Valve N276
High pressure fuel reservoir
Fuel Pressure Sensor G247
Fuel injector clamps
Fuel injectors
Positive crankcase ventilation and vacuum reservoir
Cylinder head cover
Pressure accumulator for the variable valve timing
Intake manifold module with integrated charge air
cooler

10
11
12
13
14
15
16
17
18

Camshaft Adjustment Valve 1 N205
Needle bearing
Bearing frame with camshafts
Roller-type cam follower
Camshaft 1 valves
Camshaft 2 valves
Cylinder head
High pressure EGR duct
Fuel distributor rail with high pressure EGR valve

Component overview

3

4

1
2

5
6

11

7

8

12

13
9

10

14

15

18

16

17
608_020
18

Variable camshaft timing
Introduction
Swivel motor

Variable camshaft timing is currently only used on engines
that must meet the EU6 or BIN5 Tier 2 emission standard.
Multiple variables can be controlled through camshaft
timing adjustments.
For example, a swirl charge motion can be induced by using
variable intake openings which make the use of a separate
swirl flap unnecessary. Another alternative is to adapt the
intake valve timing for advanced and/or retarded closing
which allows NOx and CO2 emissions to be reduced. Compression can also be effectively reduced by means of a
variable intake timing mechanism. This would result in
lower compression temperatures and in turn, reduce NOx
emissions.

Piston pressure
accumulator
Camshaft Position Sensor G40
608_021

The current technical innovations allow
• Optimized volumetric efficiency at full throttle
• Optimized emission reduction and fuel efficiency through
variable (and thus more effective) compression
• Maximum combustion pressure expansion utilization
• High compression ratios at cold start

Valve travel

In addition to reducing emissions, future technical developments will focus on reducing fuel consumption.

Variable valve timing is done by a hydraulically moving
(engine oil pressure) a swivel motor in the camshaft
adjuster.
When the engine is started, the swivel motor is held in the
advanced timing position by a locking element until the
required oil pressure is reached.
The active adjustment range for the intake and exhaust
valves is 50 degrees of crankshaft angle after retard.

BDC TDC BDC

Key:
1
2
3

Exhaust:
Intake:
Intake:

608_037

variable opening
variable opening
variable closing

Advance: both intake valves open simultaneously
Retard: only the rear intake valve on the “exhaust side”
opens;opening of the second intake valve is
delayed

Design
Swivel motor (stator)

Camshaft Adjustment Valve 1 N205
Cover with gear

Swivel motor (rotor)

Mechanical locking element

Cover
Spring
19

Control valve for camshaft timing adjustment

608_053

Function
The engine oil pump supplies the swivel motor with pressurized oil via a separate oil gallery in the cylinder head.
Adjustment is controlled by the ECM through a 4/2-way
proportioning valve. The ECM provides a pulse-widthmodulated signal to activate the valve.

The inner vane ring (rotor) of the swivel motor is connected
to the camshaft. The outer ring (stator) is attached to a
gear which in turn engages a gear of the belt driven camshaft. The camshaft is adjusted relative to the crankshaft
by applying oil pressure to working chambers between the
rotor and stator.

Mesh oil filter
Non-return valve

Swivel motor (rotor)

Piston pressure
accumulator

Swivel motor (stator)

Mechanical locking element
Camshaft Adjustment Valve 1 N205

Control valve for camshaft
timing adjustment

Airflow – at retarded ignition timing during the
intake cycle

608_010

Cross-section view of swivel motor

Return spring

Control valve

Camshaft Adjustment Valve 1 N205

Swivel motor (stator)

Piston pressure
accumulator

Swivel motor (rotor)
608_060

Camshaft

608_054
20

Operating ranges
A swivel motor must be subjected to a high volumetric oil
flow during the adjustment cycle to make a rapid control
response. To ensure a rapid response in the first stage at a
low pressure level, a pressure accumulator is integrated
with the adjuster. The holding pressure inside the accumulator can be up to 1.8 bar. N205 determines when the
pressure accumulator releases oil into the corresponding
port on the swivel motor based on information from the
ECM.
In the un-pressurized oil chamber, oil is expelled from the
swivel motor and forced into the return line. If the oil
gallery supply pressure is less than the pressure inside the
accumulator during camshaft adjustment, the adjustment
is assisted by the accumulator.

When the swivel motor reaches its end position, the oil
pressure in the accumulator is restored and the pressure in
the feed line is at gallery pressure.
N205 can adjust is such a way that both working chambers
are subjected to oil pressure. Depending on the oil pressure
conditions in the working chambers, both the rotor and the
camshaft are adjusted to either “advance” or ”retard”.
When the engine is switched off, the swivel motor is
adjusted to the “advanced” position by the return spring
and locked into its position.

E

Adjustment to advanced timing

N205

Engine oil pressure is admitted to working chamber A
through Camshaft Adjustment Valve 1 N205 which in
turn advances the rotor toward working chamber B.
C

F
D
B
A

B

A

608_013

Adjustment to retarded timing
The camshaft is locked in the “advanced” position. The
spring-loaded locking element is released when the oil
pressure is sufficient. N205 opens working chamber A
releasing the oil pressure into the return line. Oil pressure
from the pressure accumulator in working chamber B
displaces the swivel motor towards the “retard”
position.

Continuously variable valve timing is achieved by pulsewidth-modulated activation.

E

N205

F
C

D
B
A

B

A

Key:
A

A
B
C
D
21

B

608_012

Working chambers in the swivel motor
Oil pump
Engine lubrication system
Mesh oil filter
Non-return valve

E

Piston pressure accumulator
E1: Start of charging at approx. 0.6 bar
E2: End of charging at approx. 1.8 bar
F
Camshaft adjuster (swivel motor)
N205 Intake camshaft timing adjustment valve 1

Positive crankcase ventilation
After passing through the cylones, the blow-by gases flow
to the pressure control valve; additionally, they are then fed
into the combustion chamber through the intake manifold.

The components of the crankcase breather are integrated
into the polyamide cylinder head cover, together with the
oil filler neck and the pressure accumulator for the
vacuum system of the engine.

Positive Crankcase Ventilation Heating Valve N79 is used to
prevent the freezing of the residual moisture of the blow-by
gases during cold weather operation.

Separation of the coarse and fine oil from the blow-by
gases as well as the pressure regulation of the crankcase
also occurs in the cylinder head cover. The blow-by gases
from the crankcase flow to the coarse oil separator through
small ports and then into the cylone-type fine oil separation section.

Vacuum reservoir

Positive Crankcase
Ventilation Heating Valve
N79

Pressure control valve

Fine oil separation
(cyclones)

Oil return from fine oil separator

Gravity valve for oil recirculation
608_051

22

Oil supply
Oil circuit
Engine oil pressure is generated by a flow-rate controlled
oil pump. It is driven by the crankshaft via a separate
toothed belt. The oil pressure can be switched to a high
or a low pressure stage via the pump.

Oil pressure accumulator for variable camshaft timing

Camshaft oil gallery

Longitudinally mounted
oil filter module

Turbocharger oil supply
Oil gallery of the
hydraulic lifters

Oil Pressure Switch
F22

Reduced Oil Pressure
Switch F378

Two-stage oil pump

Piston cooling jets

Crankshaft oil gallery

Oil Level Thermal Sensor G266
608_024

23

Oil pump with integral vacuum pump
A combined oil/vacuum pump is located in the oil pan and
bolted directly to the cylinder block. It is driven by a
toothed belt. The toothed belt is immersed in engine oil
and has no belt tensioner. The tightness of the belt is
determined solely by the spacing between the components.

Oil pump toothed belt cover
with integrated crankshaft ring seal

Oil/vacuum pump integrated in the oil pan

Drive via
separate toothed belt

Connections to the vacuum supply and oil circuit

608_017

Oil Pressure Regulation Valve N428 is installed above the
sump in the cylinder block. There is a connection for the
vacuum line which leads to the engine vacuum system
directly next to this. The vacuum line is connected to the
vacuum pump by a gallery in the cylinder block.

Vacuum line from cylinder block
to vacuum equipment

Oil Pressure Regulation Valve N428

Passage to main oil gallery

Combined oil/vacuum pump integrated in the oil pan

608_038
24

Design
The oil pump is a flow-rate controlled vane pump on which
the eccentrically mounted adjustment ring allows the
delivery characteristics of the pump to be regulated. The
position of the rotating adjustment ring changes the flow
rate of the pump, and therefore allows the drive output of
the pump to be adapted to the engine’s operating
conditions.

A specially shaped engine oil pick-up ensures reliable oil
intake from the oil pan even when the vehicle is subjected
to high transverse acceleration in high speed turns and
banking.

By applying oil pressure to the adjustment ring via a control
surface, it can be swivelled against the force of the control
spring.

The air is drawn through flutter valves into the cylinder
block and ventilates its inner chamber. This air is then
admitted into the combustion chamber via the engine
breather as blow-by gas.

Vacuum
pump cover

Housing

Rotor with
vacuum pump vane

The vacuum pump inducts air from the brake servo through
a vacuum line and ports in the cylinder block.

Flutter valve

Double flutter valve

Control piston

Toothed drive pulley

Adjustment ring

Rotor with
vane cells

Oil pressure relief valve

Engine oil pick-up

Control spring

Oil pump cover
608_025

Oil pressure control
The oil pump operates in two pressure stages, which are
activated depending on engine speed.
Low pressure stage: oil pressure 1.8 – 2.0 bar

2

High pressure stage: oil pressure 3.8 – 4.2 bar

25

Oil pressure [bar]

1

2

1

Engine speed [rpm]

608_078

Function
Low delivery rate
Control surface

At low engine speeds, Oil Pressure Regulation Valve N428 is
energized when the ECM connects it to ground. This opens
the active passage to the control piston. The oil pressure
now acts on both faces of the control piston, pushing the
piston against its spring and opening the passage to the
control surface of the adjustment ring.

Adjustment ring

Small delivery chamber

The oil pressure now acts on the control surface of the
pump. The force is greater than the control spring and
swivels the adjustment ring counter-clockwise into the
center of the vane cell pump which reduces the delivery
space between the vane cells.
This lower pressure stage is activated dependent on engine
load, engine speed, oil temperature and other operating
parameters which in turn reduces the drive output requirement of the pump.

Vane cells
Control spring

Control piston
608_026

Control piston spring

Oil pan

Control piston

Non-return valve

Active oil passage

N428

Oil pressure from the oil
gallery
608_055

26

High delivery rate

Large delivery chamber

At high engine speed or load (for example, full throttle