Anti-lock Brake System (ABS)

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Anti-lock Brake System (ABS)
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Project Items

1. Abstract
2. Definition
3. Differences between ABS and without ABS
4. Components
5. Mechanism
6. ABS Type
7. summary

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Abstract

• OBJECTIVES OF THE Presentation
• To know what is the ABS .
• THE benefit of ABS
• HOW does ABS work
• Component of ABS system

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Definition

• 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.

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Differences between ABS and without ABS

• See flash gtgtgtgtgtgtgtgtgtgtgtgtgtgt

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Components

• There are four main components to an ABS speed
  sensors, valves, a pump, and a controller.
• 1-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.

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• Valves
• There is a valve in the brake line of each brake
  controlled by the ABS. On some systems, the valve
  has three positions
• A-In position one, the valve is open pressure
  from the master cylinder is passed right through
  to the brake(Wheel cylinder). Power booster
  master cylinder assembly.

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• The power booster and master cylinder assembly is
  mounted on the firewall and is activated when the
  driver pushes down on the brake pedal. It
  provides the power assistance required during
  braking.
• B-In position two, the valve blocks the line,
  isolating that brake from the master cylinder.
  This prevents the pressure from rising further
  should the driver push the brake pedal harder
• .
• C-In position three, the valve releases some of
  the pressure from the brake

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• Pump
• Since the valve is able to release pressure from
  the brakes, there has to be some way to put that
  pressure back. That is what the pump does when a
  valve reduces the pressure in a line, the pump is
  there to get the pressure back up
• 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 brakeforce
  (EBD) and activate the ABS modulator which
  actuates the braking valves on and off.
  Flashgtgtgtgtgtgtgtgtgtgtgt
• .

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Anti-Lock Brake Diagram
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Mechanism

• See gtgt.. The flash

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• ABS Type
• See the flash gtgtgtgtgtgtgtgtgtgtgt
• Four-channel, four-sensor ABSThis 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.
• Three-channel, three-sensor ABSThis scheme,
  commonly found on pickup trucks with four-wheel
  ABS, has a speed sensor and a valve for each of
  the front wheels, with one valve and one sensor
  for both rear wheels. The speed sensor for the
  rear wheels is located in the rear axle.
• This system provides individual control of the
  front wheels, so they can both achieve maximum
  braking force. The rear wheels, however, are
  monitored together they both have to start to
  lock up before the ABS will activate on the rear.
  With this system, it is possible that one of the
  rear wheels will lock during a stop, reducing
  brake effectiveness.
• One-channel, one-sensor ABSThis system is
  commonly found on pickup trucks with rear-wheel
  ABS. It has one valve, which controls both rear
  wheels, and one speed sensor, located in the rear
  axle.

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summary
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ABS brake system   The primary components of the antilock braking system are The electronic control unit, hydraulic control unit or modulator, power booster master cylinder assembly and wheel sensor unit. 
Antilock braking system operation   The antilock braking system prevents wheels locking or skidding, no matter how hard brakes are applied, or how slippery the road surface. Steering stays under control and stopping distances are generally reduced. 
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Principles of ABS braking   The antilock braking system controls braking force by controlling the hydraulic pressure of the braking system, so that the wheels do not lock during braking. 
ABS master cylinder  The tandem master cylinder transforms applied brake force into hydraulic pressure which is transferred to the wheel units through two separate circuits. This provides residual braking in the event of fluid loss. 
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Wheel speed sensors  Wheel speed sensors consist of a toothed rotor and a pickup. Wheel rotation sends input signals to the ECU, which processes them and controls the hydraulic control unit. 
Hydraulic control unit   The hydraulic control unit, or modulator, executes commands in the form of electrical signals from the ABS Control Module. It uses solenoid valves to change the hydraulic pressure in the brake circuit. 
ABS electronic control unit The ECU receives signals from various sources. The brake pedal, the ignition system, and wheel speed sensors control the hydraulic control unit and anticipate wheel lock.