ESP SSANGYONG RODIUS 2005 User Guide

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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.

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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.

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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.

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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 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.

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(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.

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5) Comparison with ABS System

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6) Hydraulic Circuit Diagram

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(1) System Overview
When equipped with ABS, the braking force at each wheel will be controlled with 3-channel 4-
sensor method. And when equipped with ESP, 4 wheels will be controlled independently with 4-
channel method. (When controlling ABS system only, it will be operated with 3-channel
method.) When compared to the vehicle equipped with ABS/EBD only, the internal hydraulic
circuit has a normally-open separation valve and a shuttle valve in primary circuit and in
secondary circuit. When the vehicle brakes are not applied during engine running or when
applying the non-ABS operating brakes, the normally-open separation valve and the inlet valve
are open, whereas the normally-closed shuttle valve and the outlet valve are closed. When the
ESP system is operating, the normally-open separation valve will be closed by the solenoid
valve operation and the hydraulic circuit will be established by the shuttle valve. Then, the inlet
and outlet valves will be
closed or open depending on the braking pressure increase, decrease or unchanged
conditions.
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▶Driving feeling when the ESP is operating
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7a007700470090009a004700960097008c00990088009b0090>ng When the ESP operates during vehicle movement, the ESP warning lamp on the instrument
panel flickers and beep comes on every 0.1 seconds. The ESP operation shows that the
vehicle stability is extremely unstable and it is used to warn the driver. The ESP system is just a
supplementary system for the vehicle motion and it cannot control the vehicle when it exceeds
the physical limits. Do not solely rely on the system but be advised to drive the vehicle safely.
When the ESP system activates, the driving feeling can be different depending on vehicle
driving conditions. For example, you will feel differently when the ESP system is activated
during when ABS is operating with the brakes applied and when brakes are not applied on a
curve. Thus, the ESP system would make the driver feel more abruptly when the brakes are
applied during the ESP system activation.
The ESP system may transfer noise and vibration to the driver due to the pressure changes
caused by the motor and valve operations in a very short period of time. Extreme cornering will
trigger the ESP operation and this will make the driver feel noise and vibration due to sudden
brake application. Also, the ESP system controls the engine output. So, the driver may notice
the engine output decrease even when the accelerator pedal is being applied.

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In this position, the separation valve and the inlet valve are open (normal open), the electrically
operated shuttle valve and the outlet valve are closed. When the brake is applied under these
conditions, the brake fluid will be sent to each wheel via the separation valve and inlet valve.

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▶When applied ABS (decreased pressure)
The pressure decreases just before the wheel speed drops and the wheels. 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.