Automotive braking systems

Automotive braking systems

• 1.
  Figure 1 http://www.autonest.org/wp-content/uploads/2011/08/TiresStopFeaturedImage.jpg Donald E Maurer
• 2.
   Your driving a car or truck. You press on the brake pedal, what happens?  A vehicle car goes through a process that multiplies the force you apply to the brake pedal with your foot and leg to stop the car.  This force is transmitted to the road through a series of parts using fluid pressure in most of today’s vehicles.
• 3.
   THE BRAKE PEDAL  There are two or three pedals in today’s vehicles.  The pedal in the middle, or the pedal that is immediately left of the gas pedal is the brake pedal.  The main purpose of the brake pedal is to multiply the force that is exerted by the driver to slow and stop the vehicle.
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   BRAKE BOOSTER  Brake boosters are only used with power braking systems. This is standard on today’s vehicles.  The booster is used to provide more braking power while reducing the required effort from the driver.  Booster’s usually operate by using the vacuum from the vehicle engine.  Not all vehicles have this type of booster. Some provide assistance electrically.  Not all vehicles will have a booster. Some will be direct pressure from the driver.
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  Figure 2 http://t0.gstatic.com/images?q=tbn:ANd9GcTC93pTwXrSYaFoEjNwglWalDE 8p83QqGmGhyjxN-0yZAZEB487
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   MASTER CYLINDER  A master cylinder is provided to convert force from the booster into hydraulic pressure.  If the vehicle does not have a booster the pressure is converted from the brake pedal.  It is easier to transfer hydraulic pressure than mechanical pressure to Figure 3 the brakes. http://www.aa1car.com/library/brake_master_cylinder.gif
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   BRAKE FLUID, LINES, AND HOSES  Fluid pressure travels from the master cylinder through the brake lines to the brakes at each wheel of the vehicle.  Brake lines are rigid except at the wheels where it is necessary to provide flexibility because of the movement of the suspension.  The rigid lines are either steel or a composite material that can withstand the corrosive environment under the vehicle.  Part of the line is steel while a short flexible material (reinforced rubber) is used to connect it to the moving parts.
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   Brake fluid must withstand extreme pressure and temperature changes. It’s VERY important that the fluid:  Cannot be compressed  Has a very high boiling point and flash point  Will not cause corrosion on the inside of brake lines  Can withstand extreme cold without thickening
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  Figure 4 http://upload.wikimedia.org/wikipedia/commons/thumb/7/76/Hydraylic_ disc_brake_diagram.jpg/619px-Hydraylic_disc_brake_diagram.jpg
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   BRAKE CALIPERS  Fluid must be converted from hydraulic pressure to mechanical pressure.  Calipers contain a piston/s that convert hydraulic fluid pressure back to mechanical pressure.  A bigger piston or multiple pistons will produce more force.  Racing or high performance applications will use 4 or even 6 pistons in the caliper.  Calipers are used with disk brake systems.
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   BRAKE PADS  Brake pads are forced against the rotor by pressure applied from the caliper.  Friction from the contact between the pad and rotor slows the speed of the rotor.  This friction produces heat.
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   BRAKE ROTORS  The rotor is acted upon by the brake pads.  The friction produced is converted into torque at the wheel.  Rotors must be able to dissipate heat.  Many rotors are made with cooling fins that help to quickly dissipate heat.  Rule of thumb – the bigger the rotor is, the better it is at reducing heat, the better the stopping power of the brakes.
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  Figure 5 http://t1.gstatic.com/images?q=tbn:ANd9GcRD- YK0vb_4ZOrSo2R_vkda2J9mAFy1LdlXZLzaotm8_o6QOvvuJg
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   WHEELS AND TIRES  The wheels and tires provide the contact between the vehicle and the road.  The primary function is to provide traction.  Traction works three ways:  Increased acceleration.  Shortened stopping distance.  Increased cornering or handling.
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  Figure 6 http://t3.gstatic.com/images?q=tbn:ANd9GcQE5qr5y0F- xlR5Jew6lFRqjjj1OIIKeiL6AImSn3GXldjLlHGd
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   The brake system is designed to increase the pressure you apply to the brake pedal.  The increased pressure is applied to the calipers through hydraulics.  The calipers convert the hydraulic pressure back to mechanical force against the rotors.  The rotors apply torque to the wheels.  The wheels and tires provide traction to stop the vehicle.
• 17.
   Erjavec, J (2010).Automotive Technology: A Systems Approach. Clifton Park, NY: Delmar, Cengage Learning. (p1424-1456) Inline Citation -- (Erjavec, 2010)
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  1. From autonest.org: http://www.autonest.org/wp- content/uploads/2011/08/TiresStopFeaturedImage.jpg 2. From seecharanautospares.com: http://t0.gstatic.com/images?q=tbn:ANd9GcTC93pTwXrSYaFo EjNwglWalDE8p83QqGmGhyjxN-0yZAZEB487 3. From aa1car.com: http://www.aa1car.com/library/brake_master_cylinder.gif 4. From upload.wikimedia.org: http://upload.wikimedia.org/wikipedia/commons/thumb/7/7 6/Hydraylic_disc_brake_diagram.jpg/619px- Hydraylic_disc_brake_diagram.jpg 5. From truckinweb.com: http://t1.gstatic.com/images?q=tbn:ANd9GcRD- YK0vb_4ZOrSo2R_vkda2J9mAFy1LdlXZLzaotm8_o6QOvvuJg 6. From forums.tdiclub.com http://t3.gstatic.com/images?q=tbn:ANd9GcQE5qr5y0F- xlR5Jew6lFRqjjj1OIIKeiL6AImSn3GXldjLlHGd