Description
Item
Battery
1
Battery junction box (BJB) in the engine
compartment
2
Generic electronic module (GEM)
3
Powertrain Control Module (PCM)
4
Instrument cluster
5
Data link connector (DLC)
6
Steering Wheel Rotation Sensor
7
ABS/ESP module or hydraulic control unit
(HCU)
8Description
Item
Combined yaw rate sensor and lateral
acceleration sensor / longitudinal
acceleration sensor
9
Front wheel sensor
10
Rear wheel sensor
11
Rear wheel sensor
12
Front wheel sensor
13
ESP switch
14
Rear brakes
15
Front brake
16
The ABS monitors the different wheel speeds of
the vehicle with the aid of wheel speed sensors.
Using the data from all of the wheel speed sensors,
the ABS module calculates the so-called reference
speed, which is a measure of the actual road
speed. The ABS module compares the individual
circumferential wheel speeds with this reference
speed when the driver initiates braking. If one or
more of the circumferential wheel speeds deviates
too far from the reference speed, this means that
slip at the affected wheels is so great that steering
stability of the vehicle is no longer ensured. The
ABS module actuates electro-mechanical valves
which influence the brake pressure at the relevant
wheels.
Like the traction control system (TCS), the ESP
system uses a large proportion of the ABS
components. In addition, there are sensors which
pick up the steering angle, the acceleration forces
acting on the vehicle and the yaw rate or yaw
moment. The sensors transmit these signals to the
combined ABS/ESP module. Using the wheel
speed and steering angle data, the ABS/ESP
module calculates the direction of travel planned
by the driver and determines the corresponding
speed-dependent lateral acceleration and yaw
moment. These values are compared with those
actual measured. If the actual lateral acceleration
and the yaw moment deviate excessively from the
target values (unstable driving characteristics), the
ABS/ESP module actuates individual brakes
selectively via the HCU (hydraulic control unit). In
addition, the engine speed is reduced by
intervention in the engine management system.
How the system works for understeer: In the
event of understeer, brake intervention occurs at
the wheels on the inside of the curve. The rear
wheel is braked heavily, so that a high amount of slip is caused. In this way, the cornering force of
the rear axle is heavily reduced and the centrifugal
force that now becomes effective turns the rear of
the vehicle back into the curve. The front wheel is
not braked as hard. The braking force that is
transmitted via the front wheel to the road surface
generates a torque with the aid of the lever arm
(vertical tire force to the vehicle's centre of gravity),
which supports the yaw moment of the vehicle.
Both measures together result in the vehicle
reverting back to the curved path intended by the
driver.
How the system works for oversteer:
In the
event of oversteer the wheels on the outside of the
curve are braked. This time, the front wheel is
subjected to a high level of slip so that the
cornering force at the front axle is reduced. The
rear wheel is not braked as heavily and, together
with the effective lever arm, results in a reduction
in the vehicle yaw moment. Both measures
together result in the vehicle being stabilized and
reverting back to the curved path intended by the
driver.
If ESP control occurs, possible ABS interventions
will be overridden as the ESP works at higher slip
rates than the ABS.
Emergency brake assist (EBA): The emergency
brake assist helps drivers in emergency braking
situations by automatically applying the brakes with
the maximum possible braking force.
If the brake pedal is pressed very suddenly, the
ABS module increases the hydraulic pressure to
all of the brakes until the threshold for ABS
intervention is reached. This applies the maximum
braking effort for the available traction. The ABS
control unit monitors inputs from the brake pedal
switch and from the pressure sensor within the
G1001304en2008.50 Kuga8/2011
206-09B- 10
Anti-Lock Control - Stability Assist
206-09B- 10
DESCRIPTION AND OPERATION
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FORD KUGA 2011.0MY WORKSHOP REPAIR MANUAL
