length BMW 745i 2002 E65 N62B44 Engine Workshop Manual

Downloaded from www.Manualslib.com manuals search engine 3
N62 Engine
Technical Data

E En
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N N6
62
2B
B4
44
4


Design 8 Cylinder V

V Angle 90°

Displacement (cm3) 4,398

Bore/Stroke (mm) 92/82.7

Cylinder Gap (mm) 98

Main Crankshaft Bearing Diameter (mm) 70

Output (kW)
at speed (rpm) 325
6,100

Torque (Nm)
at Speed (RPM) 330
3,600

Cut-off speed (RPM) 6.500

Compression Ratio 10.0

Valves / Cylinders 4

Intake Valve Diameter (mm) 35

Exhaust Valve Diameter (mm) 29

Intake Valve Lift (mm) 0.3 – 9.85

Exhaust Valve Lift (mm) 9.7

Cams Open Period (º crankshaft) 282/254

Engine Weight (kg) 213

Fuel 91 Octane

Firing Order 1-5-4-8-6-3-7-2

Knock Sensor Yes

Variable Intake Manifold Yes

Digital Motor Electronics ME 9.2 with Valvetronic Control Unit

Complies with Exhaust Emission Regulations EU-3
EU-4
LEV
Engine Length (mm) 704

Fuel Consumption Saving Compared with the M62 14%

Downloaded from www.Manualslib.com manuals search engine Fresh Air System
Air Routing
The intake air passes through the air intake duct to the air cleaner, through the throttle sec-
tion into the variable intake manifold and on to the two cylinder head intake ducts.
Increases in engine output and engine torque, as well as optimization of the engine torque
curve, are largely dependent on an optimum engine volumetric efficiency over the entire
engine speed range.
Long and short intake paths contribute to good volumetric efficiency in the lower and upper
speed ranges. Long air intake paths ensure optimum volumetric efficiency in the lower to
middle speed ranges. This optimizes the torque curve and increases the torque.
In order to optimize the power increase in the upper speed range, the engine requires short
air intake paths for better cylinder filling. The air intake system has been completely rede-
velopd in order to eliminate this inconsistency in terms of air intake path length.
The air intake system consists of the following components:
6
N62 Engine
42-02-05 Air Intake System
1. Air Intake Duct
2. Air Cleaner Housing with Intake
Air Silencer
3. Intake Pipe with HFM (Hot-Film
Air-Mass Flow Sensor)
4. Secondary Air Valves
5. Secondary Air Pump

Downloaded from www.Manualslib.com manuals search engine Intake Manifold
The N62 engine is equipped with a Variable Intake Manifold making it possible to reach a
generous torque curve even at low engine speeds, without incurring losses in engine out-
put at higher speeds. It ensures that the engine exhibits optimum volumetric efficiency
through the entire range of speeds.
The new feature is the Variable Intake Manifold intake pipe length can be adjusted depend-
ing on the engine speed to provide efficient cylinder filling and scavenging. This is deter-
mined by the optimal matching of the intake pipe dimensions, the exhaust system and the
valve timing.
The intake manifold is located in the engine “V” and is mounted on the cylinder head intake
ports.
Function
In order to understand how engine speed relates to volumetric efficiency, the physical
processes within the intake pipe must be taken into consideration.
To ensure that there is good airflow to the engine cylinders, the intake pressure in front of
the intake valve should ideally be high. This means that good airflow (high gas molecule
density) in front of the intake valve is necessary.
8
N62 Engine
42-02-47

Downloaded from www.Manualslib.com manuals search engine This is only possible if the intake valve is closed
and the mass inertia causes the intake air to
flow in front of the closed intake valve. The air is
compressed, the pressure and the air flow
increase.
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1. Closed intake valve
2. Intake manifold
As soon as the intake valve is opened, the pres-
surized intake air flows into the cylinder,
expands and draws the air molecules which fol-
low into the cylinder. The suction waves form in
the intake pipe (moving at sonic speed) in the
opposite direction to the intake air.
These suction waves are reflected in the intake
manifold and create pressure waves which then
move once more at sonic speed in the direction
of the intake valve.
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1. Pressure waves
2. Air manifold
3. Suction waves
The intake pipe is at the optimum length when the pressure waves are at the intake valve
shortly before it is closed. The increase in pressure in front of the intake valve results in
increased air flow to the cylinders once more. This process is described as recharge effect.
The opening angle of the intake valve remains unchanged as the engine speed increases.
The opening time, however, is reduced proportionately (with conventional, non-Valvetronic
engines).
Since the suction waves and pressure waves expand at sonic speed, the suction path
length must be adapted depending on the engine speed to ensure that the tip of the pres-
sure wave reaches the intake valve before it is closed.
9
N62 Engine
42-02-07
42-02-08

Downloaded from www.Manualslib.com manuals search engine Each cylinder has its own intake pipe (1) which is connected to the manifold volume (6) via
a rotor (3). The rotors are supported by one shaft (4) per cylinder bank.
The second shaft, from which the rotor for the opposite cylinder bank is adjusted, is turned
by spur gears (5) in the opposite direction from the driven shaft.
The intake air flows via the manifold volume through the funnel (2) and on to the cylinders.
The intake path length is set as the rotor turns.
The intake path length can be adjusted according to the engine speed. Adjustment from
the long to short intake path begins at 3,500 rpm. If the engine speed increases, the intake
path length is progressively reduced, up to 6,200 rpm.
N No
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10
N62 Engine
42-02-09
The Variable Intake Manifold
1. Intake Port
2. Funnel
3. Rotor
4. Shaft
5. Spur Gears
6. Manifold Volume

Downloaded from www.Manualslib.com manuals search engine The intake path length is determined by the fun-
nel position. If the engine speed is less than
3,500 rpm, the funnel is in the longer intake
path length position.
This means that the intake air must cover a
longer path to reach the cylinders.
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When an engine speed of 6,200 rpm is
reached, the rotor is adjusted to the shorter
intake path position. The intake path to the
cylinders is now short.
The funnel can be progressively adjusted to any
point between the long/short intake path posi-
tions.
• •
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Funnel adjustment is carried out by the drive unit, which is located on the rear of the intake
manifold housing. The drive motor adjusts the drive shaft with funnels (cylinder bank 1-4).
The second shaft with funnels for cylinder bank 5-8 is synchronously adjusted by the spur
gears.
The drive motor is controlled by the ECM and
provides feedback about the funnel position via
an integral potentiometer.
11
N62 Engine
42-02-11
42-02-10
42-02-81