15-10-2016, 03:06 PM
1459240522-AutomobileAntiLockBrakingSystem.docx (Size: 1.47 MB / Downloads: 7)
Abstract:
Anti-lock braking system (ABS) is an automobile safety system that allows the wheels on a motor vehicle to maintain tractive contact with the road surface according to driver inputs while braking, preventing the wheels from locking up (ceasing rotation) and avoiding uncontrolled skidding. It is an automated system that uses the principles of threshold braking which were practiced by skilful drivers with previous generation braking systems. It does this at a much faster rate and with better control than a driver could manage.
In this present paper I have made a complete and thorough analysis of Anti-Lock Braking System and also the components and necessity of them in this world.
Introduction:
An Anti-lock Braking System (ABS) is a safety system that allows the wheels on a motor vehicle to continue interacting tractively with the road surface as directed by driver steering inputs while braking, preventing the wheels from locking up (that is, ceasing rotation) and therefore avoiding skidding. Antilock braking systems (ABSs) are electronic systems that monitor and control wheel slip during vehicle braking.Itcan improve vehicle control during braking, and reduce stopping distances on slippery road surfaces by limiting wheel slip and minimizing lockup.
Reducing wheel slip improves vehicle stability and control during braking, since stability increases as wheel slip decreases.It maintains a balance between the wheel speed and the vehicle speed to avoid skidding during heavy braking.
It ensures that there is less TRACTION loss in the tyres of the vehicle.
Explanation:
History:
The ABS was first developed for aircraft used in 1929 by the Frenchautomobile and aircraft pioneer.
An early system was Dunlop's Maxaret system, which was introduced in the 1950s and is still in use on some aircraft models.
In 1958, a Royal Enfield Super Meteor motorcycle was used by the Road Research Laboratory to test the Maxaret anti-lock brake. The experiments demonstrated that anti-lock brakes can be of great value to motorcycles, for which skidding is involved in a high proportion of accidents.
Modern systems:
Honda followed suit in 1992 with the launch of its first motorcycle ABS on the ST1100 Pan European.
In 2005, Harley-Davidson began offering ABS as an option for police bikes.
In 2007, Suzuki launched its GSF1200SA (Bandit) with an ABS.
In 2008, ABS became a factory-installed option on all Harley-Davidson Touring motorcycles and standard equipment on selected models.
HYDRAULIC COMPONENTS
1.Accumulator:-
An accumulator is used to store hydraulic fluid to maintain high pressure in the brake system.
2.Antilock hydraulic control valve assembly :-
This assembly controls the release and application of the brake system pressure to the wheel brake assemblies.
3.Booster pump:-
The booster pump is used to provide pressurized hydraulic fluid to ABS.
4.Booster/Master cylinder assembly:-
It is needed to modulate hydraulic pressure in the wheel circuit during the ABS operations.
5.Fluid accumulator:-
accumulator temporarily stored brake fluid that is removed from the wheel brake unit during ABS cycle.
6.Hydraulic control unit:-
The unit may have one pump and one motor or it have one motor and two pumps.
7.Main Valve:-
This is a two position valve and is open only in the ABS mode.
8.Modulator unit:-
The modulator unit controls the flow of pressurized brake fluid to the individual wheel circuits.
9.Solenoid valves:-
The solenoid valves are located in the modulator unit and are electrically operated by signals from the control module.
ELECTRICAL/ELECTRONIC COMPONENTS
1.ABS control module:-
It monitors system operation and controls antilock function when needed.
2.Brake pedal sensor:-
Its function is to switch on the brake lights to alert other vehicles that the car is slowing down and/or is going to stop.
3.Wheel speed sensor:-
These are generally used for sensing the wheel speed.
Types Of ABS:
Three-channel,Three-sensor ABS.
One-channel,One-sensor ABS.
Four-channel,Four-sensor ABS.
MAIN COMPONENTS:
Speed sensors :- The anti-lock braking system needs some way of knowing when a wheel is about to lock up. The speed sensors, which are located at each wheel, or in some cases in the differential, provide this information
Pump :- Since the valve is able to release pressure from the brakes, there has to be some way to put that pressure back.
Controller :- The controller is an ECU type unit in the car which receives information from each individual wheel speed sensor, in turn if a wheel loses traction the signal is sent to the controller, the controller will then limit the brake force (EBD) and activate the ABS modulator which actuates the braking valves on and off.
WHO MAKES ANTILOCK BRAKES ?
• The major suppliers of antilock brakes are:
• Bendix, Acquired from Allied Signal by Bosch, used in Chrysler and Jeep products.
• Bosch, Main supplier for most imports and assorted domestic vehicles.
• Delco, Now known as Delphi, is used exclusively on GM applications.
• Continental Teves, found on various Ford, GM, Chrysler and import applications.
• Kelsey-Hayes, supplier of rear-wheel ABS and four-wheel ABS systems on Ford, Chevy and Dodge trucks.
• Nippondenso, used on Infiniti and Lexus
• Sumitomo, found on certain Mazda and Honda applications, as well as Ford Escort.
• Toyota, rear wheel only ABS systems on Toyota pickups.
ADVANCEMENT:
1)AUTOMATIC TRACTION CONTROL
Automatic traction control systems apply the brakes when a drive wheel attempts to spin and lose traction.
The system works best when one drive wheel is working on a good traction surface and the other is not
Conclusion:
Statistics show that approximately 40 % of automobile accidents are due to skidding.
These problems commonly occur on vehicle with conventional brake system which can be avoided by adding devices called ABS.
If there is an ABS failure, the system will revert to normal brake operation. Normally the ABS warning light will turn on and let the driver know there is a fault