SSANGYONG Rexton Y200 Manual page 889

4E-4 ABS AND TCS
Automatic Brake Differential (ABD)
ABD (Automatic Brake Differential) system is a type
of the TCS (ASR) system and substitutes the function
of the mechanical LSD (Limited Slip Differential)
system.
ABD system operates by controlling the braking forces
only under 60km/h.
TCS System Function
Traction control does not have any effect on the
operation of the vehicle until the control module detects
one or both of the front wheels rotating faster than the
rear wheels. At this time, the electronic brake control
module (EBCM) requests the powertrain control module
to reduce the amount of torque applied to the drive
wheels. The powertrain control module does this by
retarding timing and selectively turning off fuel
injectors. The EBCM applies the front brakes, thus
reducing torque to the front wheels. Once the front
wheel begins to rotate at the same speed as the rear
wheels, the system returns full control to the driver.
During traction control mode, if the brake is applied to
only one front wheel, most of the torque from the engine
is directed to the other front wheel which improves the
traction of the vehicle.
Pressure Modulation
Depending on the control deviation and the wheel
acceleration of the spinning wheel, pressure increase,
hold and decrease are made.
The pressure modulation is done with the conventional
control with the valves. Prime valve, inlet valve and
outlet valve according to the following table:
Increase
Open
Prime Valve
Closed
Pilot Valve
Open
Inlet Valve
Outlet Valve Closed
Speed Range
TCS is available in the speed range ≤ 60 kph.
Above 60 kph vehicle speed, TCS is passive.
It is possible to initiate TCS operation up to a vehicle
speed of 55 kph.
Hold Decrease
Open Open
Closed Closed
Closed Closed
Closed Open
Control Algorithm
The input signals for the control algorithm are the
filtered wheel speed signals from the ABS speed
processing.
With the speed difference of the driven wheels, the
control deviation is calculated.
If the control deviation exceeds a certain threshold
value, the wheel with the greater slip is braked actively.
The threshold value depends on the vehicle speed:
It is reduced with increasing vehicle speed down to a
constant value.
V = Faster rear wheel speed - Slower rear wheel
speed
V = Vehicle speed
* TCS is switched passive if the calculated temperature
is greater than a threshold value (500 °C).
•
TCS (ABD) Indicator turns on but TCS is permitted
again, when the calculated temperature is less than
350 °C.
Temperature Model
TCS operation is a high thermal load for the brakes.
To avoid any damages at the brakes, the disk
temperature is calculated with a mathematical model
for each driven wheel separately, After ignition on, the
calculation starts with 30 ° C and then three different
phases are evaluated separately and added:
TCS operation, braking and cooling phase.
If the temperature is higher than 500 °C, TCS is disabled
for this wheel.
It is permitted again, if the model has calculated down
the 350 °C.
YAD4E020
SSANGYONG Y200