SSANGYONG Rexton 2004 Service Manual page 757

Brake and cornering force
- Brake force
When depressing the brake pedal the brake force increases
to the maximum, then the brake force decreases until the
wheel locks.
- Cornering force
The cornering force is a maximum when the wheel is
turning freely with zero slip. When braking the cornering
force falls to zero if the wheel locks (slip 100 %).
- ABS operating range
The operating range starts just before the maximum brake
force and ends in maximum, for the unstable range then
begins, in which no further modulation is possible. The
ABS controls the regulation of the brake pressure so that
the brake force only becomes great enough for a sufficient
proportion of cornering force to remain. With ABS we
remain in the Kamm circle as long as the car is driving
sensibly. We will leave driving physics with these
statements and turn to the braking systems with and
without ABS.
Basic ABS Controls
Applications of the ABS control unit
The signals produced by the wheel sensors are evaluated in
the electronic control unit. From the information received, the
control unit must first compute the following variables:
- Wheel speed
- Reference speed
- Deceleration
- Slip
Reference speed
The reference speed is the mean, I.e. average speed of all wheel speeds determined by simple approximation.
Simplified ABS control
If, during braking, one wheel speed deviates from the reference speed, the ABS control unit attempts to correct that
wheel speed by modulating the brake pressure until it again matches the reference speed. When all four wheels tend to
lock, all four wheels speeds suddenly deviate from the previously determined reference speed. In that case, the control
cycle is initiated again in order to again correct the wheel speed by modulating the brake pressure.
Selector low control
This control is used for regulating the brake pressure for rear axle during ABS operation. This control uses lower
adhesion coefficient to prevent the rear wheels from locking.
ABS
REXTON SM - 2004.4
ABS-Control range
Stable Unstable
Cornering force
Slip
Brake pressure
Reference speed
EFFECTIVE DATE
8E1-5
Brake force
Y220_8E1004
Vehicle speed
Wheel speed
Y220_8E1005
CHANGED BY
AFFECTED VIN