Hba (Hydraulic Brake Assist System) - SSANGYONG Kyron Repair Manual

4. HBA (HYDRAULIC BRAKE ASSIST SYSTEM)

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 pres-
sure value of the brake pressure sensor and the pressure
changes of the pressure sensor intervals. When the sys-
tem 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.
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 depresses the brake pedal slowly, the
pressure change is not high. In this case, only the conventional brake system with booster is activated.
Operating conditions:
1. Pressure: over 20 bar
2. Pressure changes: over 1500 bar/sec
3. Vehicle speed: over 7 Km/h
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN
10
8
4
2
0
0.2
Pressure
sensor
HECU
Hydraulic line
4890
Experienced drivers
Inexperienced
drivers
Elderly and physically
weak drivers
0.4 0.6 0.8
Time (s)
ABS/ESP SYSTEM
KYRON SM - 2005.09
15
1.0