valve BMW 745i 2002 E65 N62B44 Engine Owner's Manual

Downloaded from www.Manualslib.com manuals search engine Principle of Operation
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This combi-
nation of abilities allows the ECM to control when the intake valves are opened and closed,
and also the opening lift. The intake air flow is set by adjusting the valve lift while the throt-
tle valve is fully opened. This improves cylinder filling still further and reduces fuel con-
sumption.
Each cylinder head in the N62 engine has a Valvetronic assembly. This Valvetronic assem-
bly consists of a bridge support with eccentric shaft, intermediate levers with retaining
springs, drag lever and the intake camshaft.
In addition, the following components belong to
the Valvetronic system:
• A Valvetronic motor for each cylinder head
• A Valvetronic control module
• A Valvetronic sensor for each cylinder head
The intake valve lift can be adjusted to anywhere between 0.3 mm and 9.85 mm.
The cylinder heads are precision manufactured together to ensure precise flow rate and
uniform distribution. The valve gear components on the intake side are precisely matched
together to the tightest limits.
The bridge support, lower eccentric shaft and inlet camshaft bearings are matched togeth-
er in the cylinder head once it is assembled. If the bridge support or the lower bearings are
damaged, the entire assembly must be replaced.
N No
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:

25
N62 Engines
42-02-30

Downloaded from www.Manualslib.com manuals search engine Valvetronic Motors
One Valvetronic motor is located on top of each
cylinder head towards the inside of the engine
“V”. The motors are capable of traveling from
minimum to maximum lift in 300 milli-seconds.
N No
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The Valvetronic motor must first be removed in order to remove the cylinder head
cover. The eccentric shaft must be in the minimum lift position and the motor must be
wound out from the eccentric shaft. The worm gear could otherwise be damaged when
separating the worm shaft and the worm wheel as the eccentric shaft springs back (due to
the torque compensation spring).
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The Valvetronic motor worm gear rotates the
eccentric shaft clockwise or counterclockwise
at a very quick rate (1).
Due to the progressive “lobe” on the eccentric
shaft, this rotation positions the intermediate
lever (2) closer or further to the camshaft lobe.
N No
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s:
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26
N62 Engine
1
2
Valvetronic Motor
1. Cylinder Head Cover, Cylinder Bank 1-4
2. Valvetronic Motor for Eccentric Shaft Adjustment
42-02-2943-22-28

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N62 Engine
Eccentric Shafts
The eccentric shafts (one per cylinder head) are driven by the
Valvetronic motors and are supported by four caged needle
bearing assemblies for a smooth rotation.
To assist in maintaining the set positions and counter the
valve train torque, a torque compensation spring is mounted
on the end of the shaft for tension.
Magnets are fitted in the (removable) magnetic wheel at the
end of the eccentric shaft. Together with the position sensor,
the Valvetronic Control Module determines the exact shaft
position. The eccentric shaft sensor is mounted through the
cylinder head cover (one per cylinder head) at the back.
The magnetic wheel is secured to the shaft by a bolt and is
indexed by a tab (arrow) to prevent incorrect installation.
Intermediate Lever and Roller Finger
The intermediate lever is positioned further (minimum valve
opening) or closer (maximum valve opening) to the camshaft
by the the progressive “lobe” on the eccentric shaft as it is
rotated. This offers a variable ratio effect for valve actuation.
The roller finger is used to actuate the intake valve.
The intermediate levers and roller fingers are matched (by
classification) to ensure uniform valve lift.
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42-02-3643-02-32
43-02-38
43-02-33

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N62 Engine
Valve Lift
The Valvetronic motor worm gear rotates the eccen-
tric shaft clockwise or counterclockwise at a very
quick rate (1).
Due to the progressive “lobe” on the eccentric shaft,
this rotation positions the intermediate lever (2) closer
or further to the camshaft lobe.
As the camshaft is rotating (3), the cam lobe will pivot
the intermediate lever (4) and the “heel” of the inter-
mediate lever will depress the roller finger. A spring is
located on each intermediate lever to maintain con-
stant contact with the camshaft.
The roller finger is cushioned by the HVA and will open
the intake valve (5).
The Valvetronic system varies the valve opening lift
between 0.3 mm and 9.85 mm by rotating the eccen-
tric shaft during engine operation to increase or
decrease intake (flow) into the cylinder based on throt-
tle request.
* This is an assembly that affects all of the intake
valves (per cylinder head) to work in unison.
N No
ot
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es
s:
:

1
2
3
4
5

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N62 Engine
Camshaft Sensors
The cam shaft sensors (Hall effect) are mounted through the cylinder head cover. There are
two sensors per cylinder head to monitor the intake and exhaust camshaft positions.
The sensors monitor the impulse wheels
attached to the ends of the camshafts.
Solenoid Valves
The VANOS solenoid valves are mounted through the upper timing case front cover. There
are two solenoids per cylinder head to control the oil flow to the camshaft ports for the
intake and exhaust VANOS units.
The 4/3 way proportional solenoid valve is acti-
vated by the ECM to direct oil flow. The sole-
noid valve is sealed to the front cover by a radi-
al seal and secured by a retaining plate.
N No
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s:
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42-02-48 Camshaft Sensors
1. Valvetronic Position Sensor
2. Intake Camshaft Position Sensor
3. Exhaust Camshaft Position Sensor
42-02-42

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N62 Engine
VANOS Sectional Views
M Me
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The figures above show a sectional view of one VANOS unit. The VANOS unit is secured
by a central bolt through the hub (7) to the camshaft. The timing chain connects the crank-
shaft with the housing of the unit.
There is a recess in the hub in which the locking pin (6) engages without oil pressure
(sprung). When the solenoid valve is activated to supply oil pressure to the VANOS unit,
the locking pin is compressed and releases the VANOS for adjustment.
The internal blades (9) are spring loaded (10) to provide a seal between the oil pressure
chambers (11 and 12). The torsion spring (3) acts against the camshaft torque.
42-02-4942-02-45
VANO’S Components
1. Housing with Sprocket 7. Hub
2. Front Plate 8. Black Plate
3. Torsion Plate 9. Blade
4. Lock Spring 10. Spring
5. Retaining Plate for Lock Spring 11. Pressure Chamber A
6. Spring Loaded Locking Pin 12. Pressure Chamber B

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N62 Engine
H Hy
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Ac
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n:
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When oil pressure is applied to chamber A, the blades are forced away from the VANOS
housing (counterclockwise). The blades are keyed into the hub which results in the hub
position being rotated in relation to the housing (with sprocket). The hub is secured to the
camshaft which changes the camshaft to sprocket relationship (timing).
The example below shows the a ad
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procedure together with the pressure progres-
sion based on the VANOS unit for the exhaust camshafts.
During this adjustment chamber B is open (through the solenoid) to allow the oil to drain
back through the cylinder head (internal reservoir).
Hydraulic Actuation - Chamber A
1. Front View of Vanos Unit 5. Engine Oil Pump
2. Side View of Vanos Unit 6. Supplied Oil from Pump (Switched Through Solenoid)
3. Camshaft Oil Port (Chamber B) 7. Supplied Oil Pressure (From Engine Oil Pump)
4. Solenoid Valve43-02-45

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N62 Engine
When the solenoid valve switches over, oil pressure is applied to chamber B. This forces
the blades (and hub) in a clockwise direction back to the initial position, again changing the
camshaft timing.
The example below shows the r re
es
se
et
t
procedure together with the pressure progression
based on the VANOS unit for the exhaust camshafts.
During this adjustment chamber A is open (through the solenoid) to allow the oil to drain
back through the cylinder head (internal reservoir).
N No
ot
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es
s:
:

42-02-44 Hydraulic Actuation - Chamber B
1. Front View of VANOS Unit 5. Engine Oil Pump
2. Side View of VANOS Unit 6. Oil Return (Switched through Solenoid)
3. Camshaft Oil Port (Chamber B) 7. Supplied Oil Pressure (From Engine Oil Pump)
4. Solenoid Valve

Downloaded from www.Manualslib.com manuals search engine 34
N62 Engine
The chart below shows the VANOS unit camshaft adjustment possibilities. The valve lift
adjustment has also been incorporated.
The special feature of Valvetronic is that the air mass drawn in the cylinders can be easily
determined by the valve lift and closing time. The air mass can then be limited, thus the
term “load control”.
With the help of VANOS, the valve closing point can be easily selected within a defined
range. With valve lift control, the opening duration and cross section of the valve opening
can also be easily selected within a defined range.
Vacuum pump
The N62 engine requires a vacuum pump for the vacuum
assisted brake booster. With the throttle valve open while the
car is being driven, additional vacuum is needed.
The N62 vacuum pump has a second vacuum connection
(small hose) for the exhaust flap adjustment. The vacuum
pump is driven by cylinders 1-4 exhaust camshaft via the
VANOS unit. The pump is lubricated through an oil gallery
from the cylinder head.
42-02-03
Chart Exhaust & Intake Valve
1. Exhaust Valve Open
2. Exhaust Valve Closed
3. Intake Valve Open
4. Intake Valve Closed

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N62 Engine
Chain Drive
The camshafts are driven by a toothed chain, one for each cylinder bank. The oil pump is
driven by a separate roller chain.
1. Sensor wheels for the camshaft position sensor, cylinder bank 1-4
2. Tensioner Rail, Cylinder 5-8
3. Chain Tensioner, Cylinder Bank 5-8
4. Sensor Wheel for the camshaft position sensor, cylinder bank 5-8
5. Upper timing chain guide with integrated oil jet
6. Guide rail
7. Sprocket for Oil Pump Drive
8. Timing case lower section
9. Tensioning rail, cylinder bank 1-4
10. Solenoid Valve, VANOS exhaust camshaft
11. Solenoid Valve, VANOS intake camshaft
12. Upper Timing Chain Cover
13. Chain Tensioner, Cylinder Bank 1-4
14. VANOS exhaust camshaft Bank 1-4
15. Upper Timing Chain guide with integrated oil jet
16. VANOS intake camshaft 1-4Chain Drive
43-02-50