2005 BMW 745i N62B44 Engine Workshop Manual

Downloaded from www.Manualslib.com manuals search engine Valvetronic
Over the entire speed and load range, the gasoline engine needs a combustible fuel-air
mixture within the ideal ratio (Lambda = 1). The mixture quantity must be altered to vary the
speed and output. This variation is effected by the throttle valve. The mixture, which falls
within the narrow range of Lambda = 1, is formed outside the combustion chamber using
the fuel injection system (external mixture formation).
The mixture control is influenced by the throttle valve and is not optimal in all the different
load ranges. This is particularly true in the idle to part-load ranges, since the throttle valve
is only opened slightly in these ranges. The consequences are less than optimal cylinder
filling, torque and increased fuel consumption.
Technical measures were previously introduced; such as the optimization of air/fuel mixing,
improved valve overlap, introduction of DISA and the steady improvement of mixture con-
trol all depend on the throttle valve. This is where the new completely unique Valvetronic
design comes in.
The Valvetronic system simultaneously varies the valve opening time and the valve opening
lift between 0.3 mm and 9.85 mm, according to engine speed and load. This means that
the air/fuel mixture volume is controlled according to engine requirements. This type of mix-
ture and volume control makes the typical throttle valve control unnecessary.
23
N62 Engine

Downloaded from www.Manualslib.com manuals search engine Physical considerations:
On engines with throttle valve control, the throttle valve is slightly open in the idling and part-
load ranges. This results in the formation of up to 500 mbar vacuum in the intake manifold,
which prevents the engine from aspirating freely and in turn prevents optimum cylinder fill-
ing. The Valvetronic system with an open throttle valve largely counteracts this disadvan-
tage. The air-mass flow to the intake valves is unrestricted. The full ambient pressure is
available directly at the intake valves for cylinder filling and scavenging.
The Valvetronic system primarily controls the fill by adapting the valve opening time and the
valve lift (short opening time/small valve lift = lower fill, and vice versa). During the valve
opening phase the engine aspirates more freely via the intake valves even with small valve
lifts vs. a throttle valve which is continuously blocked.
The slower cylinder filling from the intake valves with partial lift results in more turbulence in
the combustion chamber, thus faster and better mixture control and more efficient com-
bustion. At lower engine speeds this effect is intensified by opening the intake valves later,
after top dead center (ATDC) using VANOS. This increases vacuum in the combustion
chamber which accelerates filling and turbulence when the intake valves are opened.
I In
n
s
su
um
mm
ma
ar
ry
y,
,
the additional variability of the Valvetronic system results in optimization of
cylinder filling and scavenging throughout the engine's entire operating range. This has a
positive effect on output, torque and a decrease in fuel consumption and exhaust emis-
sions.
F Fe
ea
at
tu
ur
re
es
s:
:
• Valve lift adjustment
• VANOS for intake and outlet
• Variable intake manifold
• Mixture control and ignition control
• Other individual engine design measures
T Th
hi
is
s
r
re
es
su
ul
lt
ts
s
i
in
n:
:
• Improved engine idling
• Improved engine torque
• Improved engine torque curve
• Fewer pollutant emissions
T Th
he
es
se
e
b
be
en
ne
ef
fi
it
ts
s
r
re
es
su
ul
lt
t
i
in
n
a
a
c
cl
le
ea
ar
r
i
im
mp
pr
ro
ov
ve
em
me
en
nt
t
i
in
n
p
pe
er
rf
fo
or
rm
ma
an
nc
ce
e
a
an
nd
d
f
fu
ue
el
l
c
co
on
ns
su
um
mp
pt
ti
io
on
n
r
re
ed
du
uc
c-
-
t ti
io
on
n
(
(1
14
4%
%)
)
f
fo
or
r
t
th
he
e
d
dr
ri
iv
ve
er
r.
.
24
N62 Engine
T Th
he
e
m
ma
ai
in
n
b
be
en
ne
ef
fi
it
ts
s
o
of
f
t
th
he
es
se
e
f
fe
ea
at
tu
ur
re
es
s
a
ar
re
e:
:
• Improved cylinder filling with air/fuel mix-
ture
• Improved mixture control before the cylin-
der inlet
• Improved combustion procedure

Downloaded from www.Manualslib.com manuals search engine Principle of Operation
T Th
he
e
V
Va
al
lv
ve
et
tr
ro
on
ni
ic
c
s
sy
ys
st
te
em
m
i
is
s
a
a
c
co
om
mb
bi
in
na
at
ti
io
on
n
o
of
f
V
VA
AN
NO
OS
S
a
an
nd
d
v
va
al
lv
ve
e
l
li
if
ft
t
a
ad
dj
ju
us
st
tm
me
en
nt
t.
.
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
ot
te
es
s:
:

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
ot
te
e:
:

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).
I If
f
i
it
t
i
is
s
n
no
ot
t
p
po
os
ss
si
ib
bl
le
e
t
to
o
r
re
em
mo
ov
ve
e
t
th
he
e
m
mo
ot
to
or
r,
,
d
du
ue
e
t
to
o
m
me
ec
ch
ha
an
ni
ic
ca
al
l
f
fa
ai
il
lu
ur
re
e
o
or
r
s
st
ti
ic
ck
ki
in
ng
g,
,
t
th
he
e
w
wo
or
rm
m
s sh
ha
af
ft
t
c
ca
an
n
b
be
e
m
mo
ov
ve
ed
d
u
us
si
in
ng
g
a
an
n
A
Al
ll
le
en
n
k
ke
ey
y
t
to
o
r
re
el
le
ea
as
se
e
t
th
he
e
m
mo
ot
to
or
r.
.
A
A
h
ho
ol
le
e
m
mu
us
st
t
b
be
e
d
dr
ri
il
ll
le
ed
d
i
in
n
t
th
he
e
r re
ea
ar
r
p
pl
la
as
st
ti
ic
c
m
mo
ot
to
or
r
c
co
ov
ve
er
r
i
in
n
o
or
rd
de
er
r
t
to
o
a
ac
cc
ce
es
ss
s
t
th
he
e
m
mo
ot
to
or
r
s
sh
ha
af
ft
t
(
(w
wo
or
rm
m
s
sh
ha
af
ft
t)
)
u
us
si
in
ng
g
t
th
he
e
A
Al
ll
le
en
n
k
ke
ey
y.
.
T Th
he
e
m
mo
ot
to
or
r
c
ca
an
n
t
th
he
en
n
n
no
o
l
lo
on
ng
ge
er
r
b
be
e
u
us
se
ed
d.
.
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
ot
te
es
s:
:

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

Downloaded from www.Manualslib.com manuals search engine 27
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.
N No
ot
te
e:
:
W
Wh
he
en
n
d
di
is
sa
as
ss
se
em
mb
bl
li
in
ng
g/
/a
as
ss
se
em
mb
bl
li
in
ng
g
t
th
he
e
v
va
al
lv
ve
et
tr
ra
ai
in
n,
,
t
th
he
e
i in
nt
te
er
rm
me
ed
di
ia
at
te
e
l
le
ev
ve
er
rs
s
a
an
nd
d
r
ro
ol
ll
le
er
r
f
fi
in
ng
ge
er
rs
s
m
mu
us
st
t
b
be
e
r
re
et
tu
ur
rn
ne
ed
d
t
to
o
t
th
he
e
o or
ri
ig
gi
in
na
al
l
p
po
os
si
it
ti
io
on
ns
s
t
to
o
p
pr
re
ev
ve
en
nt
t
u
un
ne
ev
ve
en
n
c
cy
yl
li
in
nd
de
er
r
c
ch
ha
ar
rg
gi
in
ng
g
w
wh
hi
ic
ch
h
c ca
an
n
r
re
es
su
ul
lt
t
i
in
n
r
ro
ou
ug
gh
h
i
id
dl
le
e
a
an
nd
d
e
en
ng
gi
in
ne
e
p
pe
er
rf
fo
or
rm
ma
an
nc
ce
e
c
co
om
mp
pl
la
ai
in
nt
ts
s.
.

R Re
ef
fe
er
r
t
to
o
t
th
he
e
R
Re
ep
pa
ai
ir
r
I
In
ns
st
tr
ru
uc
ct
ti
io
on
ns
s
f
fo
or
r
t
to
ol
le
er
ra
an
nc
ce
e
n
nu
um
mb
be
er
rs
s!
!
42-02-3643-02-32
43-02-38
43-02-33

Downloaded from www.Manualslib.com manuals search engine 28
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
te
es
s:
:

1
2
3
4
5

Downloaded from www.Manualslib.com manuals search engine 29
N62 Engine
Bi-VANOS (Variable Camshaft Adjustment)
The N62 features compact infinitely variable vane-type VANOS for the intake and exhaust
camshafts. The VANOS unit is easy to remove and install. The VANOS unit is designed as
an integral component of the chain drive and is secured to the respective camshaft with a
central bolt. The camshaft adjustment rate is 60º (as compared with the crankshaft).
The VANOS unit gear teeth are visibly different to match the new toothed chain. The
VANOS unit for the cylinders 1-4 exhaust shaft has mounting provisions for the vacuum
pump drive. A spring plate is fitted between the VANOS unit and the vacuum pump drive
to reduce wear (3). The V VA
AN
NO
OS
S
u
un
ni
it
ts
s
a
ar
re
e
l
la
ab
be
el
le
ed
d
“
“I
In
n/
/O
Ou
ut
t”
”
for intake and exhaust installa-
tion positions.
The VANOS units are supplied with oil via ports in the camshafts. The oil ports are located
on the left and right of the thrust bearing. Depending on the individual VANOS adjustment
direction, the VANOS is supplied with oil via either the rear oil ports (1 & 2) or the front oil
ports (3 & 4). The oil moves through the camshaft to the VANOS units.
VANOS Units
1. VANOS Unit Exhaust Side
2. VANOS Central Bolt
3. Spring Plate
4. VANOS Unit Intake Side
5. Toothed Chain Gear Teeth
VANOS Oil Ports
1&2. Rear Oil Duct with Four Holes
3&4. Front Oil Duct with Four Holes
5. Front Oil Duct Outlets
6&7. Hook Sealing Washer.43-02-39

Downloaded from www.Manualslib.com manuals search engine 30
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
ot
te
es
s:
:

42-02-48 Camshaft Sensors
1. Valvetronic Position Sensor
2. Intake Camshaft Position Sensor
3. Exhaust Camshaft Position Sensor
42-02-42