SSANGYONG RODIUS 2007 Service Manual

0-7
BRAKS SYSTEM
RODIUS 2006.09
4830-01
4) Master Cylinder
The brake master cylinder is designed to
convert the force from the brake maste
r
cylinder to the high hydraulic pressure. The
brake system uses the tandem type master
cylinder with in-line 2 pistons.
The in-line 2 pistons generate the hydraulic
pressure. The piston cup on the piston keeps
the sealing conditions in cylinder and
prevents the oil leaks. The hydraulic
pressure generated by the primary piston is
delivered to the front wheels, and the
hydraulic pressure generated by the
secondary piston is delivered to the rea
r
wheels.
5) Brake Booster
The brake booster is a power assist device for brake system. It relieves the pedal depressing
force by using the pressure difference between the vacuum pressure generated by vacuum
pump in intake manifold and the atmospheric pressure.
▶Pressure distribution at working
When depressing the brake pedal, the push
rod (1) in booster pushes the poppet (2) and
valve plunger (3). The poppet (2) pushes the
power piston seat (5) resulting in closing the
vacuum valve (9). The chamber (A) and (B)
in power cylinder are isolated and the valve
plunger (3) is separated from the poppet (2).
And then the air valve (6) opens and ai
r
flows into the chamber (B) through filter.
Then, the power piston (5) pushes the
master cylinder push rod (7) to assist the
brake operation.
▶Pressure distribution after working
When releasing the brake pedal, the valve
plunger (3) returns back to the original
position by return spring (4) and the air valve
(6) closes. At this time, the vacuum valve (9)
opens and the pressure difference between
chamber (A) and (B) in power cylinder is
eliminated. Accordingly, the power piston (5)
returns back to original position by the
reaction of master cylinder (10) and the
diaphragm return spring (8).

0-8
RODIUS 2006.09
4830-01
BRAKS SYSTEM
6) Master Cylider & Booster
ABS system is basically equipped to STAVIC.
Vehicle which adapted ESP system in option has two pressure sensors under master cylinder
and these two sensor are used for BAS (Brake Assist System) system.
Do not disassemble the brake oil pressure sensors These can not be reinstalled of
disassembled.
After reinstall the reserver tank perform a air bleeding of brake system
-
-
Vehicle with ESP Vehicle with ABS
Brake fluid reservoir tank Master cylinder

0-3
ESP SYSTEM
RODIUS 2006.09
4892-01
8510-56ABS/ESP System
1. SPECCIFICATIONS OF ESP SYSTEM
1) Specifications Of Pressure Sensor
2) Specifications Of Sensor Cluster
(sensor cluster: yaw rate sensor + lateral acceleration sensor + Longitudinal acceleration sensor)
3) Specifications Of Wheel Speed Sensor
4) Specifications Of Steering Wheel Angle sensor

0-4
RODIUS 2006.09
4892-01
ESP SYSTEM
1. COMPONENTS AND LOCATIONS
2WD vehicle has the longitudinal sensor in the HECU.
1. HECU: (Hydraulic &
Engine conrol unit) 2. Pressure sensor 3. Wheel speed sensor
4. Sensor cluster:
(Yaw rate + lateral sensor + longitudinal sensor) 5. Steering wheel angle
sensor 6. ESP off switch (Electronic
Stability Program Switch) ESP Warning lamp

0-5
ESP SYSTEM
RODIUS 2006.09
4892-01
2. INPUT AND OUTPUT DIAGRAM

0-6
RODIUS 2006.09
4892-01
ESP SYSTEM
3. ESP SYSTEM DESCRIPTION
1) Principle of ESP
ESP (Electronic Stability Program) recognizes critical driving conditions, such as panic
reactions in dangerous situations, and stabilizes the vehicle by wheel-individual braking and
engine control intervention with no need for actuating the brake. This system is developed to
help the driver avoid the danger of losing the control of the vehicle stability due to under-
steering or over-steering during cornering.
The yaw rate sensor, lateral sensor and longitudinal sensor in the sensor cluster and the
steering wheel angle sensor under the steering column detect the spin present at any wheels
during over-steering, under-steering or cornering. The ESP ECU controls against over-steering
or under-steering during cornering by controlling the vehicle stability using the input values from
the sensors and applying the brakes independently to the corresponding wheels.
The system also controls during cornering by detecting the moment right before the spin and
automatically limiting the engine output (coupled with the ASR system).
Understeering is when the steering wheel is
steered to a certain angle during driving and
the front tires slip toward the reverse
direction of the desired direction. Generally,
vehicles are designed to have unde
r
steering. The vehicle can return back to
inside of cornering line when the steering
wheel is steered toward the inside even
when the vehicle front is slipped outward.
As
the centrifugal force increases, the tires can
easily lose the traction and the vehicle tends
to slip outward when the curve angle gets
bigger and the speed increases. Under steering
ESP controls during under steering
The ESP system recognizes the directional
angle with the steering wheel angle senso
r
and senses the slipping route that occurs
reversely against the vehicle cornering
direction during understeering with the yaw
rate sensor and the lateral sensor. Then the
ESP system applies the brake at the rea
r
inner wheel to compensate the yaw moment
value.
In this way, the vehicle does not lose its
driving direction and the driver can steer the
vehicle as driver intends.

0-7
ESP SYSTEM
RODIUS 2006.09
4892-01
Over steeringOversteering is when the steering wheel is
steered to a certain angle during driving and
the rear tires slip outward losing traction.
When compared with under steering
vehicles, the controlling of the vehicle is
difficult during cornering and the vehicle can
spin due to rear wheel moment when the
rear tires lose traction and the vehicle speed
increases.
ESP controls during oversteering
The ESP system recognizes the directional
angle with the steering wheel angle senso
r
and senses the slipping route that occurs
towards the vehicle cornering direction
during oversteering with the yaw rate senso
r
and the lateral sensor. Then the ESP system
applies the brake at the front outer wheel to
compensate the yaw moment value.
In this way, the vehicle does not lose its
driving direction and the driver can steer the
vehicle as he or she intends.
2) ESP Control
The ESP system includes the ABS/EBD and ASR systems allowing the system to be able to
operate depending to the vehicle driving conditions. For example, when the brakes are applied
during cornering at the speed of 100 km/h, the ABS system will operate at the same time the
ASR or ABD systems operate to reduce the power from the slipping wheel. And when yaw rate
sensor detects the rate exceeding 4¡Æ/seconds, the ESP system is activated to apply the
brake force to the corresponding wheel to compensate the yaw moment with the vehicle
stability control function. When various systems operate simultaneously under a certain
situation, there may be vehicle control problems due to internal malfunction of a system o
r
simultaneous operations. In order to compensate to this problem, the ESP system sets the
priority among systems. The system operates in the order of TCS (ASR or ABD), ESP and
ABS. The order may be changed depending on the vehicle driving situations and driving
conditions. As the single-track vehicle model used for the calculations is only valid for a vehicle
moving forward, ESP intervention never takes place during backup.

0-8
RODIUS 2006.09
4892-01
ESP SYSTEM
2) ESP Control
The ESP system includes the ABS/EBD and ASR systems allowing the system to be able to
operate depending to the vehicle driving conditions. For example, when the brakes are applied
during cornering at the speed of 100 km/h, the ABS system will operate at the same time the
ASR or ABD systems operate to reduce the power from the slipping wheel. And when yaw rate
sensor detects the rate exceeding 4¡Æ/seconds, the ESP system is activated to apply the
brake force to the corresponding wheel to compensate the yaw moment with the vehicle
stability control function. When various systems operate simultaneously under a certain
situation, there may be vehicle control problems due to internal malfunction of a system o
r
simultaneous operations. In order to compensate to this problem, the ESP system sets the
priority among systems. The system operates in the order of TCS (ASR or ABD), ESP and
ABS. The order may be changed depending on the vehicle driving situations and driving
conditions. As the single-track vehicle model used for the calculations is only valid for a vehicle
moving forward, ESP intervention never takes place during backup.

0-9
ESP SYSTEM
RODIUS 2006.09
4892-01
3) Vehicle Control During Cornering
The figure below shows the vehicle controls by ESP system under various situations such as
when the brake pedal is pressed (or not pressed) during cornering and when the ABS is
operating or when just the conventional brake is operating during braking. It also includes the
vehicle conditions when the TCS that is included in the ESP system is operating.

0-10
RODIUS 2006.09
4892-01
ESP SYSTEM
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 drive
r
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 senso
r
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.