2005 BMW 745i N62B44 Engine Workshop Manual

Downloaded from www.Manualslib.com manuals search engine Secondary Air Pump (SLP)
The electrically-operated secondary air pump is mounted to the vehicle body. The pump
draws out filtered fresh air from the air cleaner housing during the warm-up phase and sup-
plies it to the two secondary air Non-return Valves.
Once the engine has been started, the secondary air pump is supplied with voltage by the
ECM via the secondary air pump relay. It remains switched on until the engine has taken in
a certain amount of air.
The O ON
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period may be a maximum of 90 seconds and it depends on the following engine
operating conditions:
• Coolant temperature (from -10 ºC to approximately 60 ºC)
• Air temperature (NTC sensor in HFM)
• Engine speed
One non-return valve is mounted on each cylinder head (see also Engine Views).
The non-return valves are opened by the pressure generated from the secondary air pump.
The secondary air is led through a pipe to the secondary air ducts (integral in the cylinder
heads) for distribution into the exhaust ports.
The non-return valves are sprung closed when the secondary air pump is deactivated. This
prevents exhaust vapors, pressure and condensation from flowing back into the secondary
air pump.
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N62 Engine
43-02-14
View From Rear of The Cylinder Head
1. Cylinder Head Lead
2. Non-return Valve (SLV)
3. Secondary Air Pump Connection

Downloaded from www.Manualslib.com manuals search engine Ancillary Components and Drive Belts
Drive Belts
The belt drive has two components and is subdivided into the main and A/C drives. Both
belts are driven by the crankshaft pulley.
A 4 rib belt is used to drive the air conditioning compressor and a 6 rib belt is used for the
main drive. Each drive belt has a maintenance free tensioning unit with tensioning pulley
and torsioner.
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The tensioning pulley is pushed back using a
Torx tool in the recess provided (1) and fixed in
this position by inserting a locking pin as shown
(2).
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N62 Engine
42-02-15 Ancillary Components and
Drive Belts
1. Air Conditioning Compressor
2. 4 Rib A/C Drive Belt
3. Crankshaft Pulley
4. Water Pump
5. Tensioning Unit Main Drive Belt
6. Alternator
7. Deflection Pulley
8. Power Steering Pump
9. 6 Rib Drive Belt
10. Tensioner Unit A/C Drive Belt
42-02-16

Downloaded from www.Manualslib.com manuals search engine Alternator
Due to the high power capacity of 180 A, the alternator is cooled by the engine's cooling
system to enhance heat dissipation. The brushless Bosch alternator is installed in an alu-
minum housing which is mounted to the engine block. The exterior alternator walls are sur-
rounded with circulated engine coolant. The function and design of the alternator is the
same as in the M62, with only minor modifications. The BSD interface (bit-serial data inter-
face) for the ECM is new.
* Further details found in the cooling circuit
section
Regulation
The alternator communicates with the Engine Control Module (ECM) via the BSD (bit-seri-
al data interface). The alternator conveys data such as model and manufacturer. This is
necessary to allow the engine management system to adapt it’s calculations and specific
control to the type of alternator fitted.
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N62 Engine
42-02-17
Alternator
1. Watertight Housing
2. Rotor
3. Stator
4. Seal
Alternator Coolant Flow
1. Coolant Return Flow
2. Coolant Inlet Flow
42-02-18

Downloaded from www.Manualslib.com manuals search engine The ECM takes on the following functions:
• Activation/deactivation of the alternator.
• Informing the alternator regulator of the nominal voltage value to be set.
• Controlling the alternator's response to load.
• Diagnosing the data line between the alternator and the ECM.
• Storing alternator fault codes.
• Activating the charge indicator lamp in the instrument cluster.
The connection with the ECM makes it possible to equalize the alternator load torque for
nearly all operating conditions. This supports the engine idling speed control and the bat-
tery load balance. In addition, the ECM receives information from the Power Module about
the battery's calculated temperature and charge status. This means that alternator output
can be adapted precisely to the temperature and load status of the battery which increas-
es the battery service life.
The charge indicator display strategy has not changed in comparison with the alternators
currently in use. Regulating the alternator output is particularly important when activating
Valvetronic operating motors.
A temperature protection function is implemented in the voltage regulator. If the alternator
overheats, the alternator voltage is reduced until an appropriate temperature has been
reached.
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• Mechanical faults such as blockages or belt drive failure.
• Electrical faults such as exciter diode defects or over/under voltage caused by regula-
tion defects.
• Connection defects between the ECM and the alternator.
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N62 Engine

Downloaded from www.Manualslib.com manuals search engine N No
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The alternator regulator voltage is influenced by the ECM - BSD interface. The bat-
tery charge voltage can therefore be up to 15.5 V, depending on the battery temperature.
If a battery charge voltage of up to 15.5 V is measured, the regulator is not faulty. A high
charge voltage indicates a low battery temperature.
Air Conditioning Compressor
The “clutch free” A/C compressor is manufac-
tured by Denso. It functions continuously with
the engine running. The compressor is a 7-
cylinder swash plate type. The displacement
can be reduced to less than 3% when air con-
ditioning is not requested (no refrigerant is sup-
plied to the refrigerant circuit).
There is an internal compressor refrigerant cir-
cuit to maintain lubrication. The IHKA electron-
ics regulate the compressor output via an
external control valve (1).
Starter Motor
The starter motor is located on the right-hand
side of the engine below the exhaust manifold,
and is a compact planetary drive starter with a
1.8 kW output.
1. Starter motor with heat protective cover.
Power Steering Pump
The power steering pump is a tandem radial piston pump on vehicles equipped with
Dynamic Drive. A single vane pump is installed on vehicles without the Dynamic Drive.
Further information about the power steering pump can be found in the Chassis Dynamics
section.
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N62 Engine
42-02-19
42-02-03

Downloaded from www.Manualslib.com manuals search engine Cylinder Heads
The two N62 cylinder heads are a new development from BMW. They are fitted with the
Valvetronic system. The secondary air ducts for subsequent exhaust gas treatment are
integrated in the cylinder heads. The cylinder heads are cooled by the “cross-flow” princi-
ple.
The inlet camshaft and the Valvetronic eccentric shaft are jointly guided by a bridge sup-
port. The cylinder heads are made from aluminum and are manufactured using gravity die-
casting. The upper timing chain housing is now an integral part of the cylinder head.
20
N62 Engine
Cylinder Head
1. Cylinder Head for Cylinder Bank 1-4 7. Mounting VANOS Intake Solenoid
2. Cylinder Head for Cylinder Bank 5-8 8. Mounting VANOS Outlet Solenoid
3. Upper Timing Chain Guide with Oil Jet 9. Oil Pressure Switch
4. Mounting for VANOS Intake Solenoid 10. Chain Tensioner Mount
5. Mounting for VANOS Outlet Solenoid 11. Upper Timing Chain Guide with Oil Jet
6. Chain Tensioner Mount43-02-20

Downloaded from www.Manualslib.com manuals search engine Engine Covers
Each cylinder head has a plastic cover for the ignition coil cabling and top of the cylinder
head. The covers “push fit” into rubber grommets on the cylinder head covers.
A sound absorption cover for the top of the
engine also covers the two Valvetronic motors.
This cover is fixed to the intake manifold hous-
ing using four bolts.
The cylinder head covers are made from plastic. The retaining sleeves for the ignition coils
have molded-on gaskets. The sleeves must be replaced if any hardening or damage is vis-
ible on the gaskets. The sleeves are inserted into the cylinder head through the cylinder
head cover (nos. 1through 4).
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Engine Covers
Cylinder Head Cover
1. Cylinder Head Top Cover
2. Sound Absorption Engine Cover
1-4. Opening for Spark Plugs
5. Pressure Control Valve
6. Opening for Valvetronic Motor
7. Opening for Valvetronic Sensor Connector
8. Camshaft Sensors (Intake and Exhaust)
43-02-12

Downloaded from www.Manualslib.com manuals search engine Cylinder Head Gaskets
The cylinder head gasket is a multi-layer steel
gasket with a rubber coating. This type of gas-
ket has previously been used on other engines.
The B44 head gasket has a 6 mm hole in a flap
on the outlet side of the cylinder head gasket.
The cylinder head bolts for the N62 engine are
M10x160 necked-down “stretch” bolts.
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The lower part of the timing chain housing is
bolted to the cylinder head using two M8x45
bolts.
Camshafts
The camshafts are made from chilled cast iron
and are hollowed to reduce weight. The cam-
shafts are weighted with counterbalances for
equalizing imbalances in the valve gear.
1. Camshaft sensor wheels (sintered metal)
2. Thrust bearing area with oil ducts for the
VANOS units
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