PP presentation for ED 653

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.

4.  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.

5. Figure 2
http://t0.gstatic.com/images?q=tbn:ANd9GcTC93pTwXrSYaFoEjNwglWalDE
8p83QqGmGhyjxN-0yZAZEB487

6.  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

7.  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.

8.  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

9. Figure 4
http://upload.wikimedia.org/wikipedia/commons/thumb/7/76/Hydraylic_
disc_brake_diagram.jpg/619px-Hydraylic_disc_brake_diagram.jpg

10.  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.

11.  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.

12.  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.

13. Figure 5
http://t1.gstatic.com/images?q=tbn:ANd9GcRD-
YK0vb_4ZOrSo2R_vkda2J9mAFy1LdlXZLzaotm8_o6QOvvuJg

14.  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.

15. Figure 6
http://t3.gstatic.com/images?q=tbn:ANd9GcQE5qr5y0F-
xlR5Jew6lFRqjjj1OIIKeiL6AImSn3GXldjLlHGd

16.  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)

18. 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