tow bar FORD KUGA 2011 1.G Workshop Manual

Rear Drive Axle and Differential – System Operation andComponent Description
System Operation
General Information
The powertrain with all-wheel drive consists of the
following main components:
• engine
• transaxle with front axle differential
• transfer box
• halfshafts and driveshafts
• Haldex clutch
• rear axle differential
The Haldex clutch guarantees continuous variable
torque transmission to the rear axle under all
driving conditions. The Haldex clutch reacts
immediately and equally quickly with slow or fast
wheel slip.
A difference in angle of rotation of 90° between the
input and output shafts is required to build up
maximum pressure at the multi-plate clutch or to
transmit maximum torque.
The advantage of vehicles with all-wheel drive is
that they distribute the drive between all four
wheels. They therefore have a higher tractive
power. They feature improved cornering behaviour,
as the grip at all four wheels can be better utilised.
Thus, the wheels contribute to a greater degree
towards cornering stability.
The engine torque is transmitted from the transfer
box to the rear axle via a driveshaft. The driveshaft
is flange-mounted to the input side of the Haldex
clutch.
Driving situations
Pulling away and accelerating
• When pulling away and accelerating, as muchall-wheel drive as necessary must be available
immediately in the short-term. During
acceleration, the electronic system detects slip
at the front axle. This slip is counter-controlled
and thus the propulsive force optimally
distributed to the two axes.
Cornering • A sporty driving style, in particular dynamic
cornering, demands stable cornering behaviour.
The all-wheel system distributes the propulsive
force to all four wheels and by so doing boosts
the high cornering forces so that the vehicle
makes optimum contact with the road surface.
Snow and black ice
• Snow and black ice require particularly high grip. Under these conditions, the Haldex clutch
always distributes the propulsive force to the
axle with the better traction. The all-wheel
system reacts intelligently and quickly to all
driving situations.
Trailer operation
• When driving with a trailer, the trailer weight (support load) is transmitted to the rear axle via
the towbar. This reduces the load on the front
wheels, which means they can slip. The
electronic system detects this difference and
distributes most of the propulsive force to the
rear axle.
Haldex clutch
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205-02- 6
Rear Drive Axle/Differential
205-02- 6
DESCRIPTION AND OPERATION
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Action
Possible Sources
Symptom
• CHECK ride height, VERIFYcorrect spring rate and CHECK
items under Halfshaft Joint
Pullout. REPAIR or INSTALL
new as necessary.
• Excessively high CV joint oper-
ating angles caused by incor-
rect ride height.
• Shudder Vibration During
Acceleration.
• INSPECT and INSTALL newas necessary.
• Excessively worn or damaged
inboard front wheel driveshaft
joint or outboard front wheel
driveshaft joint.
• INSPECT and REPAIR orINSTALL new as necessary.
• Inboard driveshaft bearing
retainer circlip missing or not
correctly seated in differential
side gear.
• Halfshaft Joint Pullout
• CHECK engine mounts fordamage or wear. REPAIR or
INSTALL new as necessary.
• Engine/transaxle assembly
mispositioned.
• CHECK underbody dimensions.REFER to REFER to
Section 501-00 [Body System
-General Information] .
• Frame rail or strut tower out of
position or damaged.
• CHECK for worn bushings orbent components (front stabil-
izer bar, front suspension lower
arm). REPAIR or INSTALL new
as necessary.
• Front suspension components
worn or damaged.
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Front Drive Halfshafts
205-04- 4
DIAGNOSIS AND TESTING
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than to a change in the throttle valve position. The
ignition timing also changes much more quickly.
To keep the ignition point as close as possible to
the knock limit and so optimize the efficiency of the
engine, two KS are installed in the engine, which
pick up the mechanical vibrations of the engine
and convert them into an electrical signal for the
PCM.
TIE42093
1
2
A
B1
2
Description
Item
Normal combustion
A
Knocking combustion
B
Pressure characteristic in cylinder
1
Output signal from KS
2
The term "knocking" is used to describe
combustion processes in which the flame front
propagation speed reaches the speed of sound.
This can happen towards the end of combustion
in particular, when unburnt air/fuel mixture on the
combustion chamber walls self-ignites due to the
increase in pressure following initiation of regular
combustion. The resulting pressure peaks damage
the pistons, cylinder head gasket and cylinder
head.
The cylinder in which combustion knock is
occurring is identified from the camshaft position (CMP sensors) and crankshaft position (CKP
sensor) information.
If the PCM detects combustion knock, the ignition
timing for the cylinder in question is gradually
retarded for a few crankshaft revolutions until
combustion knock stops. After that the ignition point
is slowly returned to the calculated value. This
facilitates individual cylinder ignition, which makes
it possible for the engine to operate at optimum
efficiency at the knock limit.
Engine fueling
Fuel is supplied by a non-return fuel system.
Fuel pressure and fuel delivery rate are regulated
by the PCM with the aid of the FPDM. The fuel
pump is supplied with a cycled voltage by the
FPDM. By cycling the voltage, the fuel pump output
can be steplessly adjusted. The fuel pressure can
be steplessly regulated between 3 and 5 bar.
Adjusting the fuel pump output has the following
advantages:
• The fuel pump's power consumption is reduced,
thereby reducing the load on the vehicle's power
supply system.
• The fuel pump's service life is increased.
• Fuel pump noise is reduced.
Fuel pressure regulator
The PCM calculates the required fuel pressure
based on the operating conditions. The PCM
transmits a corresponding PWM signal to the
FPDM. With the aid of this signal, the FPDM
actuates the pump by sending, in turn, a PWM
signal to the ground connection of the fuel pump.
The fuel pump can be steplessly regulated by
varying the pulse width of the PWM signal.
The PCM continuously monitors the fuel pressure
in the fuel rail by means of the fuel temperature/fuel
pressure sensor. If the pressure deviates from the
calculated value, the PCM adapts the PWM signal
to the FPDM accordingly. Thus the fuel pressure
levels out at approx. 4 bar.
For safety reasons, the PCM switches off fuel
delivery if the SRS (supplemental restraint system)
module detects a crash.
Regulation of injected fuel quantity
The electromagnetically controlled injectors dose
and atomize the fuel. The quantity of injected fuel
is regulated by the duration of actuation of the fuel
injectors. The fuel injectors are either closed (not
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Electronic Engine Controls— 2.5L Duratec (147kW/200PS) - VI5303-14-
20
DESCRIPTION AND OPERATION
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