SSANGYONG REXTON 2006.09 Manual page 404

17-5
4892-01
OVERVIEW AND OPERATION PROCESS
1. SUMMARY
The aim of the ABS is to mmaintain steerability and driving stability and to take the burden off
the driver. If the stopping distance is shorter on some road surfaces (carriageway conditions),
this is a gift of physics and not a development aim.
ABS is a device which senses that one or more of the wheels are locking up during braking. It
monitors the rotational speeds of the wheels and reduces hydraulic pressure to any wheel it
senses locking up. It is controlled by both mechanical and electronic components. When you
apply the brakes, the ABS will regulate the flow of brake fluid being delivered to the brake
calipers. By the use of electronic computers, the brakes rapidly alternate (at a rate of 30 times
per second) from full pressure to full release.
1) DRIVING PHYSICS
To give you a better understanding of the tasks and functions of ABS, we will first look at the
physics principles.
(1) The Stopping Distance
The stopping distance depends on the vehicle weight and initial speed when braking starts.
This also applies for vehicle with ABS, where ABS always tries to set an optimum brake force
on each wheel. As great forces are exerted between the tires and the carriageway when
braking, even with ABS the wheels may scream and rubber is left on the road. With an ABS
skid mark one may be able to clearly recognize the tire profile. The skid mark of an ABS vehicle
does not however leave any hint of the speed of the vehicle in the case of an accident, as it can
only be clearly drawn at the start of braking.
(2) Brake Force On A Wheel
The maximum possible brake force on a wheel depends on the wheel load and the adhesion
coefficient between tire and carriageway. With a low adhesion coefficient the brake force, which
can be obtained is very low. You are bound to know the result already from driving on winter
roads. With a high adhesion coefficient on a dry road, the brake force, which can be obtained,
is considerably higher. The brake force, which can be obtained, can be calculated from below
formula:
ANTI-BRAKE SYSTEM
REXTON 2006.09