2012 SSANGYONG RODIUS lock

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1. SPECIFICATIONS
1) Pressure Sensor
UnitDescription
Location
ABS ESP
HECU
(Hydraulic &
Electronic Control
Unit) CPU:MCU60 (32bit)
Clock Frequency: 28MHz
Memory: 128~256 KB CPU:MCU60 (32bit)
Clock Frequency: 28MHz
Memory:256~512 KB Under the front
washer reservoir
Wheel Speed
SensorActive type wheel speed
sensorActive type wheel speed
sensorOn each wheel
Front air gap:
0.335~0.945mm,
Rear air gap:
0.309~0.958
Steering Wheel
Angle SensorN/AMaximum angular speed:
1500°/sec
Operating voltage: 9~16VUnder the steering
wheel
Sensor ClusterN/AIntegrated with yaw rate
sensor and lateral sensorUnder the audio
assembly
Pressure Sensor
N/A Analog outputUnder the master
cylinder
Description Specification
Supplying voltage approx. 5V (4.75~5.25V)
Max. pressure 350bar

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1. ESP (Electronic Stability Program)
ESP system contains the ABS (Anti-Lock Brake System), ABD (Automatic Braking Differential),
ASR (Acceleration Slip Regulation), Cornering Control and HBA (Hydraulic Brake Assist System)
functions.
▶Cornering Control (Understeer and Overersteer) Function
This function controls the vehicle stability by applying the braking pressure on each wheel
according to the yaw rate, lateral sensing value and driver’s steering wheel control.
▶HBA (Hydraulic Brake Assist System) Function
HBA (Hydraulic Brake Assist) system helps in an emergency braking situation when the driver
applies the brake fast, but not with sufficient pressure, which leads to dangerously long braking
distance. ECU recognizes the attempt at full braking and transmits the signal calling for full brake
pressure from the hydraulic booster.

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3. OPERATING PROCESS
1) Block Diagram of Input and Output

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(2) Hydraulic Circuit of HBA
The above figure shows one front and one rear wheel and the same hydraulic circuit forms as in
the ESP operation. When HECU recognizes that it is an emergency and it is required for hard
braking, depending on the pressure value of the brake pressure sensor and pressure changes
caused by the pressure sensor timing, it operates the pump immediately to apply the brake
pressure at the wheels. Then, the pressure in the pump increases until just before the
corresponding wheel gets locked. The motor still keeps rotating and the outlet valve and the
separation valve will stay closed. When the wheel starts to lock, the HBA function cancels and
switches to ABS operation.

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▶DUMP (ESP is working) Mode
The pressure decreases just before the wheel speed drops and the wheels are locked.
The inlet valve closes and the outlet valve opens as in the ABS HECU and the oil is gathered at
the low pressure chamber while no additional oil is being supplied. Then the pump operates to
allow fast oil drainage. The shuttle valve and the separation valve do not operate while
decompression.

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▶RISE (ESP is working) Mode
The shuttle valve and inlet valve will be open and the separation valve and outlet valve will be
closed. Then, the pump is operated. When ESP operates while the ABS is operating, the pressure
will be increased continuously until just before the corresponding wheel gets locked.

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1. SYSTEM OVERVIEW
When braking suddenly or braking on slippery roads, the vehicle keeps moving forward but the wheels
are locking and not rotating. If these happen, the vehicle may lose stability or rotate resulting in an
accident. ABS helps to maintain directional stability and control of the vehicle. ABS is designed to secure
more safety and increase the control of steering wheel during emergency braking situation. But, ABS
does not guarantee perfect safety beyond its physical limit. ABS in this vehicle contains EBD function. In
normal driving conditions, the brake system operates without ABS function.
1) Basic Theory of ABS Function
To give you a better understanding of the tasks and functions of ABS, we will first look at the physics
principles.
▶Stopping distance
The stopping distance depends on the vehicle weight and initial speed when braking starts. This also
applies for vehicle with ABS, where ABS always tries to set an optimum brake force on each wheel. As
great forces are exerted between the tires and the carriageway when braking, even with ABS the wheels
may scream and rubber is left on the road. With an ABS skid mark one may be able to clearly recognize
the tire profile. The skid mark of an ABS vehicle does not however leave any hint of the speed of the
vehicle in the case of an accident, as it can only be clearly drawn at the start of braking.
▶Brake force on a wheel
The maximum possible brake force on a wheel depends on the wheel load and the adhesion coefficient
between tire and carriageway. With a low adhesion coefficient the brake force, which can be obtained is
very low. You are bound to know the result already from driving on winter roads. With a high adhesion
coefficient on a dry road, the brake force, which can be obtained, is considerably higher. The brake
force, which can be obtained, can be calculated from below formula:

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2) Maximum Brake Force
FBmax = wheel load FR x coefficient of friction (Mh)
The braking process cannot be described
sufficiently accurately with the brake forces
calculated. The values calculated only apply if
the wheel is not locked. In the case of a locking
wheel, the static friction turns into lower sliding
friction, with the result that the stopping distance
is increased. This loss of friction is termed "slip"
in specialist literature.