ABS System.pptx

ABS System.pptx

• 2.
  • Anti-lock BrakingSystem (ABS) is an automobile safety system that prevents the wheels of a vehicle locking as brake pedal pressure is applied- often suddenly in a emergency situation or short stopping distance. The ABS enables the driver to have steering control preventing him from skidding and loss of traction of the vehicle.
• 3.
  In 1929 ABSwas first developed for aircraft by the French automobile and aircraft pioneer Gabriel Voisin, as thrashold braking on airplanes is nearly impossible. In 1936 German company was awarded a patent an “Apparatus for preventing lock-braking of wheels in a motor vehicle”. First ABS was installed in US vehicles in 1985. And now almost every car and new line of motorcycles are equipped with ABS
• 4.
  Under hard brakingan ideal braking system should: Provide the shortest stopping distances on all surfaces. Maintain vehicle stability and steer ability.
• 5.
  • When thedriver pushes brake pedal during driving, the wheel speed decreases and the vehicle speed does as well. The decrease in the vehicle speed, however, is not always proportional to the decrese in the wheel speed. The non-correspondance between the wheel speed and vehicle speed is called “Slip” and the magnitude of the slip is expressed by the “slip ratio” which is defined as follows: • Slip ratio- (vehicle Speed-wheel speed)/vehicle speed*100% • When the slip ratio is 0%, the vehicle speed corresponds exactly to the wheel speed and when its 100%, the wheels are completely locked(rotating at a zero speed) while the vehicle is moving.
• 6.
  • ABS Systemconsists of 4 primary components- 1- ABS Controller: it is the brain of the system. It reads inputs and then controls the system to keep the wheels from locking up and skidding
• 7.
  3- ABS Modulator:Some systems have separate valves for each wheel with a modulator to control them. Other systems they are combined, in either case they work with the controller and the pump to add or release pressure from the individual wheels brakes to control the braking. 4-ABS Pumps: Since the abs modulator walls can release pressure from the individual wheels breaks their needs to be a way to restore the pressure when required this.That is what the abs pumps job is when the pump is cycling the driver may experience a slide pedal vibration. This cycling is happening many times per second and the slight vibration is natural
• 8.
  We will discusshow ABS works in a vehicle:  Sensors at each of four wheels sense the rotation of the wheel.  Too much break application → wheel stops rotation  Sensors →ECU →release break line pressure→wheel turns again.  Then ESU applies pressure again stops the rotation of the wheel and so on.
• 9.
   This releasingand re-application or pulsing of brake pressure happens 20-30 times per second or more.  This keeps the wheel just at the limit before locking up and again skidding no matter.  ABS system can maintain extremely high static pressure and must be disabled before attempting repairs
• 10.
  • ABS BlockDiagram:
• 11.
   One-channel, onesensor ABS: This system is commonly found on pickup trucks with rear wheel ABS. It has one valve, which controls both the rear wheels and one speed sensor, located in the rear axle.  Three-channel, three sensor ABS: This scheme commonly found on pick up tracks with four wheel ABS, has a speed sensor and valve for each of the front wheels, with one valve and one sensor for both real wheels. The speed sensor for the rear wheel is located in the rear axle.
• 12.
   Four channel,four-sensor ABS: This is the best scheme, there is a speed sensor on all four wheels and a separate valve for all four wheels. With this setup the controller monitors each wheel individually to make sure it is achieving maximum braking force.
• 13.
   Advantages- • Itallows the driver to maintain direct stability and control our 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 modulus the pulses that permitting the wheel to continue turning under maximum braking pressure.
• 14.
   Disadvantages- • Stoptimes- Anti lock braks are made to provide for surer braking in slippery conditions. However some drivers report that they find the stopping distance is for regular conditions were increased by their abs system either because their may be errors in the system or because noises of the abs may contribute to the driver not braking at the same rate • Delicate Systems- It's easy to cause a problem in an ABS system by messing around with the brakes. Problems include disorientation of the abs system where it compensating break sensor causes the vehicle to sudder, make loud noises or generally brake worse.
• 15.
   Disadvantages- • Cost-An abs can be expensive to maintain. expensive sensors on each will can cost and rates of dollars to fix it if they get out of calibration or develop other problems for some this is a big reason to decline an abs in a vehicle. • System damage- A variety of factors can cause the system to be less effective and can present with everything forms to vehicle to loud noises while trying to stop
• 16.
  • The antilockbraking system controls breaking force by controlling the hydraulic pressure of the system braking, so that the wheels do not lock during breaking. • The antilock braking system prevents wheels looking or skidding, no matter how hard breaks are applied, or how slippery the road surface. Stearing stays under control and stopping distance are generally reduced.