Antilock braking system (ABS)

This ppt describes about the working of ABS and components, advantages and a short video clip explain clearly about the ABS. There also the be comparison for the car with ABS and without ABS in form of short GIF.

1. ANTI-LOCK BRAKING SYSTEM (ABS) BY, T DEEPAKKUMAR(180021601018) A DHANASEKAR(180021601019) DINESH(180021601020)

2. WHAT IS ABS? Anti-lock braking system (ABS) is an automobile safety system which prevents the wheels from locking and enables safe braking. ABS are electronic systems that monitor and control wheel slip during vehicle braking. ABS can 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.

3. HISTORY OF ABS ABS was first developed for aircrafts in 1929 by French automobile and aircraft pioneer Gabriel Voisin. The German companies Bosch and Mercedes-Benz pioneered the first electronic version for use on Mercedes-Benz cars in 1936. In 1960 a fully mechanical system used in the Ferguson p99 racing car, the Jensen FF and the Ford Zodiac so that the system was expensive. In 1975 Ford also introduced ABS on the Lincoln Continental Mark III and the Ford LTD station Wagon called “Sure Trak”. In 1978 Bosch and Mercedes-Benz introduced the first completely Electronic 4-wheel multi channel ABS system in trucks and the Mercedes Benz S-class. In 1988 BMW become the world’s first motorcycle manufacture to introduce an electronic /hydraulic ABS system, this on their BMW K100. In 1992 Honda launched its first ABS system this on the ST 1100 Pan European.

4. MOTIVATION OF ABS DEVELOPMENT Under hard braking, an ideal braking system should: Provide the shortest stopping distances on all surfaces. Maintain vehicle stability and steering ability.

5. ABS BLOCK DIAGRAM:

6. WORKING PRINCIPLE OF ABS System consists of a central (ECU) Electronic Control Unit and four wheel speed sensors connected to each wheel and two hydraulic valves. There is a valve in the brake line of each brake controlled by the ABS and the valve has three positions: 1 st _ The valve is open, pressure from the master cylinder is passed right through to the brake. 2 nd _ The valve blocks the line, isolating that brake from the master cylinder. 3 rd _ In position three, the valve releases some of the pressure from the brake. When the ECU finds that any wheel that any wheel is turning faster than the other wheel, automatically brake hydraulic pressure to the affected wheel is increased by the ABS system so that braking force is reapplied and the wheel slows down.

7. WORKING PRINCIPLE OF ABS This complete process is performed by the ABS is repeated continuously throughout the drive on mostly uneven roads and can be easily detected by the driver of the car with the help of brake pedal pulsation. ABS COMPONENTS

8. ABS WORKS:

9. VIDEO FOR ABS:

10. ABS COMPONENETS: Hydraulic components: Accumulator - It is used to store hydraulic fluid to maintain high pressure. Antilock hydraulic control valve assembly - It controls the release and application of the brake system pressure. Booster pump - It is used to provide pressurized hydraulic fluid. Booster/Master cylinder assembly - It is needed to modulate hydraulic pressure in the wheel circuit. Fluid accumulator - It temporarily stores brake fluid that is removed from the wheel brake. Main valve - This is a two position valve and is open only in the ABS mode. Modulator unit - It controls the flow of pressurized brake fluid to the individual wheel circuits. Solenoid valves - It is located in the modulator unit and are electrically operated by signals from the control module.

11. ABS COMPONENETS: Electrical/Electronic components : ABS control module - It monitors system operation and controls antilock function when needed. Brake pedal sensor - Its function is to switch on the brake lights to alert other vehicles that the car is slowing down or is going to stop. Wheel speed sensor - These are generally used for sensing the wheel speed.

12. TYPES OF ANTI-LOCK BRAKING SYSTEM FOUR CHANNEL, FOUR SENSOR ABS: This is the best scheme, there is speed sensor and a separate valve for all the four wheels. Three channel, three sensor ABS: This scheme is commonly found on pick up trucks with four wheels ABS, has a speed sensor and a valve for each of the front wheels, with one for both rear wheels. One channel, one sensor ABS: It has one valve, which controls both rear wheels, and one speed sensor, located in the rear axle.

13. HOW EFFECTIVE IS IT? Certain older models can be bought without ABS, and some people do prefer not having it. It is a very effective safety feature : Cars fitted with ABS are less likely be involved in a fatal crash. ABS decreases the chance of frontal collision on wet and dry roads. Cars with ABS rarely stray from the road ahead. It is worth keeping in mind that ABS works best on solid stable surfaces and your experience on ice, snow or gravel can be different .

14. COMPARISON : Wheel lockup during braking causes skidding which in turn cause a loss of traction and vehicle control. This reduces the steering ability to change direction, so the car slides out of control. With ABS system, the driver can brake hard, take the evasive action and still be in control of the vehicle in any road condition at any speed and under any load.

15. FEATURES AND BENEFITS OF ABS: FEATURES BENEFITS Control of steering Increases steering ability and vehicle stability during braking Fail-safe electrical/electronic system If the electrical/electronic system fails, the ABS is shut off. Traction control It is an optional feature that controls excessive wheel spin during acceleration ABS Indicator lamp Informs the driver or technician that an ABS fault has occurred.

16. ADVANTAGES AND DISADVANTAGES ADVANTAGES: It allows the driver to maintain directional stability and control over steering during braking. Safe and effective. Automatically changes the brake fluid pressure at each wheel to maintain optimum brake performance. ABS absorbs the unwanted turbulence shock waves and modulates the pulses thus permitting the wheel to continue turning. DISADVANTAGES: It is very costly. Maintenance cost of a car equipped with ABS is more.

17. 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 knows there is a fault.