SsangYong Korando III (2010 year). Manual — part 242

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3) Vehicle Control During Cornering

The figure below shows the vehicle controls by the ESP system under various situations such as when

the brake pedal is depressed or not depressed during cornering, when the ABS is operating and when

braking without the ABS. It also includes the vehicle conditions when the TCS, a part of the ESP system,

is operating.

Condition

Understeer control

Oversteer control

Only ESP in

operation

No braking by driver

ESP

+

Normal braking

(no ABS operation)

ESP

+

ABS brake

ESP + ASR

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4) HBA (Hydraulic Brake Assist System)

(1) Purpose

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. An inexperienced, elderly or physically weak driver may suffer from the accident by not

fully pressing the brake pedal when hard braking is required under emergency. The HBA System

increases the braking force under urgent situations to enhance the inputted braking force from the driver.

Based on the fact that some drivers depress the brake pedal too soft even under when hard braking is

necessary, the HECU system is a safety supplementary system that builds high braking force during

initial braking according to pressure value of the brake pressure sensor and the pressure changes of the

pressure sensor intervals. When the system is designed to apply high braking force when brake pedal is

depressed softly by an elderly or physically weak driver, the vehicle will make abrupt stopping under

normal braking situation due to high braking pressure at each wheels.

(2) Operation

The brake pressure value and the changed value of the pressure sensor are the conditions in which the

HBA System operates. There are 2 pressure sensors under the master cylinder. When the ESP ECU

system determines that emergency braking is present, the pump operates, the brake fluid in the master

cylinder is sent to the pump and the braking pressure is delivered to the wheels via the inlet valves . If the

drive depress the brake pedal slowly, the pressure change is not high. In this case, only the conventional

brake system with booster is activated.

(3) Operating conditions

Sensor pressure: over 40 bar

Pressure changes: over 850 bar/sec

Vehicle speed: over 30 km/h

-

-

-

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5) ARP (Active Roll-Over Protection)

The ARP (Active Roll-over Protection) system is a safety assistant device that minimizes, by controlling

brakes and the engine, the physical tendency of the vehicle rollover during sharp lane changes or U-

turns. For the system, software is added to the existing ESP system and no additional device or switch is

needed. One must note that the ARP system, just as general assistant devices including the ABS, is only

a safety assistant device using the ESP system and its function is useless when the situation overcomes

the physical power. Following picture shows how the ARP compensates the vehicle position by varying

each wheel's braking power to overcome the physical tendency of the vehicle rollover during sharp turns.

Lateral sensor

(In sensor cluster)

Vehicle speed

Brake force

Radius

The vehicle driving condition is controlled by the internally programmed logic according to the input

signals from wheel speed sensor, steering angle sensor and lateral sensor.

During the ARP operation, vehicle safety (rollover prevention) takes the first priority and thus,

stronger engine control is in effect. Consequently, the vehicle speed decreases rapidly, so the driver

must take caution for the vehicle may drift away from the lane.

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6) HSA (Hill Start Assist)

The HSA (Hill Start Assist) prevents the vehicle from rolling backward by supplying the hydraulic

pressure to the wheels by the HECU after the brake pedal is released when starting off on uphill.