brake sensor SSANGYONG RODIUS 2007 User Guide

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ABS SYSTEM
RODIUS 2006.09
4892-01
(3) Basic ABS Controls
Applications of the ABS control unit
The signals produced by the wheel sensors
are evaluated in the electronic control unit.
From the information received, the control
unit must first compute the following
variables:
- Wheel speed
- Reference speed
- Deceleration
- Slip
Reference speed ▶
The reference speed is the mean, I.e. average speed of all wheel speeds determined by simple
approximation.
Simplified ABS control ▶
If, during braking, one wheel speed deviates from the reference speed, the ABS control unit
attempts to correct that wheel speed by modulating the brake pressure until it again matches
the reference speed. When all four wheels tend to lock, all four wheels speeds suddenly
deviate from the previously determined reference speed. In that case, the control cycle is
initiated again in order to again correct the wheel speed by modulating the brake pressure.
Selector low control ▶
This control is used for regulating the brake pressure for rear axle during ABS operation. This
control uses lower adhesion coefficient to prevent the rear wheels from locking.

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ABS SYSTEM
RODIUS 2006.09
4892-01
3. ABS SYSTEM DESCRIPTION
1) EBD (ELECTRONIC BRAKE FORCE DISTRIBUTION) SYSTEM
(1) System Description
As an add-on logic to the ABS base algorithm, EBD works in a range in which the intervention
thresholds for ABS control can not be reached. EBD ensures that the rear wheels are
sensitively monitored for slip with respect to the front axle. If slip is detected, the inlet valves fo
r
the rear wheels are switched to pressure hold to prevent a further increase in pressure at the
rear-wheel breaks, thus electronically reproducing a pressure-reduction function at the rear-
wheel brakes. ABS features an enhanced algorithm which includes control of the brake force
distribution between the front and rear axles. This is called Electronic Brake Distribution. In an
unloading car condition the brake efficiency is comparable to the conventional system but for a
fully loaden vehicle the efficiency of the EBD system is higher due to the better use of rear axle
braking capability.
(2) The Benefits of EBD
Elimination of conventional proportioning valve EBD utilizes the existing rear axle wheel
speed sensor to monitor rear wheel slip.
Based on many variables in algorithm a pressure hold, increase and/or decrease pulsetrain
may be triggered at the rear wheels insuring vehicle stability.
Vehicle approaches the ideal brake force distribution (front to rear).
Constant brake force distribution during vehicle lifetime.
EBD function is monitored via ABS safety logic (conventional proportioning valves are not
monitorable).
“Keep alive” function. -
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RODIUS 2006.09
4892-01
ABS SYSTEM
Service precautions ▶
Observe the following general precautions during any ABS/TCS service. Failure to adhere to
these precautions may result in ABS/TCS system damage.
Disconnect the EBCM harness connector before performing the electric welding procedures.
Carefully note the routing of the ABS/TCS wiring and wiring components during removal.
The ABS/ TCS components are extremely sensitive to EMI (eletromagnetic interference).
Proper mounting is critical during component service.
Disconnect the EBCM connector with the ignition OFF.
Do not hang the suspension components from the wheel speed sensor cables. The cables
may be damaged.
Do not use petroleum based fluids in the master cylinder. Do not use any containers
previously used for petroleum based fluids. Petroleum causes swelling and distortion of the
rubber components in the hydraulic brake system, resulting in water entering the system
and lowering the fluid boiling point. 1.
2.
3.
4.
5.

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RODIUS 2006.09
4892-01
ABS SYSTEM
2) HYDRAULIC CIRCUIT DIAGRAM
(1) Hydraulic Circuit of ABS
The vehicle equipped only with the ABS controls the wheel’s braking force using three 3-
channel 4-sensor method. The front wheels that are the primary circuit of the brake system is
composed of two wheel speed sensors and two channel valves system with two inlet valves
and two outlet valves. The rear wheels that are the secondary circuit of the brake system is
composed of two wheel speed sensors, one inlet valve and one outlet valve. This system is
similar to the one from the previous model.

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RODIUS 2006.09
4892-01
ABS SYSTEM
Pumping
▶
ECU (Including Solenoid Valves ? ESP Equipped Model)
▶
ECU lower cover)
▶
When the cam pushes the left plunger
during motor operation, the system pressure
is generated in the left cylinder. At this time,
the right plunger is expanded by spring force
and the expanded volume of the right
cylinder draws the brake fluid.
HECU controls the hydraulic valves by
supplying or cutting off the voltage to
solenoid valves depending on the wheel
speed and other information from wheel
speed sensors.
The figure shown in left side is for ESP
ECU. There are two channels for front
wheels and one channel for rear wheels.
Each channel has one inlet and one outlet
valve, therefore,
there are six solenoid valves.
The electrical components are weak to
moisture. To protect ECU, GoreTex-based
plate is used at ECU lower cover. The vent
hall (arrow) allows air to ventilate but does
not allow moisture to penetrate.