This will help you fix your own vehicle

1. TOYOZU TECHNICAL
SCHOOL FOUNDATION, INC.
ATS NC II TRAINING SESSION
Batch 2021

2. Lord, help us in our online studies
today. Give us concentration so that
may we listen, understand, learn and
have peaceful mind and may we
always remember that god is always
with us
OPENING PRAYER

3. Good
Morning!
TTSFI ATS NC II Trainees

4. Lesson:
Air Brake System

5. Objectives:
 Discuss the purpose of air brake
system
 Identify the component parts of air
brake system
 Explain the working principle of
braking system
ATS NC II Training Session

6. Lesson:
Air Brake System

7. What is Air Brake
System?

8. BRAKE:
 A brake is a device by means of which
frictional resistance is applied to a moving
machine member, in order to retard or stop
the motion of a machine.

9. BRAKE:
A brake is a mechanical device which inhibits
motion, slowing or stopping a moving object
or preventing its motion.

10. BRAKE:
Most commonly brakes use friction between two
surfaces pressed together to convert the kinetic
energy of the moving object into heat to slow down
the motion of vehicle.

11.  A brake which uses air as working fluid is a
pneumatic brake. The system actuated to apply
this phenomenon is known as Pneumatic Brake
System.
 An pneumatic brake or a compressed air brake
system, is a type of friction brake for vehicles in
which compressed air pressing on a piston is
used to apply the pressure to the brake pad
needed to stop the vehicle.

12. George Westinghouse first developed pneumatic
brakes for use in railway service. He patented a safer
air brake on March 5, 1872. Westinghouse made
numerous alterations to improve his air pressured
brake invention, which led to various forms of the
automatic brake used in modern vehicles for more
safer and advance braking system.
In the early 20th century, after its advantages were
proven in railway use, it was adopted by
manufacturers of bus ,trucks and heavy road vehicles.

19.  Brake system that is based upon a design Air patented by George
Westinghouse on March 5 1872. The Westinghouse Air Brake Company
Organization (WABCO) was subsequently organized to manufacture
and sell Westinghouse invention which has been universally adopted.
 Compressed air from compressor passes through the valve and
maintains its pressure. This air is stored in the reservoir. And from the
reservoir it goes to the Brake Chambers through many brake valves. In
the brake chamber this pneumatic force is converted into the
mechanical force and then it is converted into the rotational torque by
the slack adjuster, which is connected to S-cam. This torque applies air
brakes which is used to slow down the motion of the veichle.

20. Braking is done into three stages:

21. During this stage, brake pipe is charged to
5kg/cm2 pressure which in turn charges control
reservoir and auxiliary reservoir to 5 kg/cm2
pressure via distributor valve.
At this stage brake cylinder gets vented to
atmosphere through passage in Distributor
valve and there is no application of brake in
the stage.

22.  For application of brakes, the pressure in
brake pipe has to be dropped. This is done by
venting air from driver’s brake valve.
Reduction in brake pipe pressure positions
the distributor valve in such a way that the
control reservoir gets disconnected from
brake pipe and auxiliary reservoir gets
connected to brake cylinder.

23.  The magnitude of braking force is
proportional to reduction in brake pipe
pressure which is done by the application of
force on the brake pedal.

24.  For releasing brakes, the brake pipe is again
charged to 5 kg/cm2 pressure by compressor
through driver’s brake valve.
This action positions distributor valve in such a
away that auxiliary reservoir gets isolated from
brake cylinder.
Brake cylinder is vented to atmosphere through
distributor valve and thus brakes are released.

25. The air brake system is actually three separate
systems :-

26. SERVICE BRAKE:
This system applies and releases the brakes when
the driver pushes/releases the brake pedal. Pushing
the brake pedal, opens a valve to let air flow from
the air tank through the airlines to a brake
chamber.
PARKING BRAKE :
Parking brake releases air from the brake chamber
which allows the brake spring to expand and forces
the pushrod out which pushes a slack adjuster that
turns the camshaft, twisting the S-Cam and forcing
the brake linings against the brake drum.

27. EMERGENCY BRAKE:
When there is insufficient air in the system to keep the spring in the
chamber restrained, the emergency brakes automatically engage.
When air pressure falls below 420 kpa, a low pressure warning light
will come on along with an audible buzzer. If air pressure continues
to fall, the emergency brake will automatically apply when air
pressure drops to 140-310 kpa. The fail safe engineering of air
brakes will not allow you to control activation of the emergency
brake so look for a safe place to pull off the roadway as soon as the
low pressure warning activates.

28. Air is available everywhere in atmosphere so the brake system can never
run out of its operating fluid.
Air doesnot corrode the metals so the life of pneumatic brake is more.
Air line couplings are easier to attach and detach than hydraulic lines there
is no danger of letting air into a pneumatic circuit.
Pneumatic brake has got emergency brake which gets activated when the
service brake failed, so it is very safe.
Air brakes are effective even with considerable leakage, so an air brake
system can be designed with sufficient fail-safe capacity to stop the
vehicle safely even when leaking.

29. If the brakes are applied before recharging
has been completed, a larger brake pipe
reduction will be required in order to achieve
the desired amount of braking effort.
If the brake pipe pressure is too low due to
an excessive no. of brake applications, an
emergency application will not produce a
large enough volume of air flow to trip the
triple valves, leaving the engineer with no
means to stop the vehicle.
This system is complicated and needs
trained person to use it.

30.  The pneumatic brake is mainly used in large
vehicles such as trucks, buses, trailers, and semi-
trailers in addition to their use in railway train.

31. Operation of pneumatic brake is
different from more common
hydraulic systems, so most people
require additional training and
licensing in order to legally drive
any vehicle using an air brake
system.
Driving a vehicle with air brakes
requires basic knowledge of
proper maintenance as well. A
driver should have knowledge
to inspect the air pressurization
system prior to driving and
make sure all tanks are in
working order.

32. Done…

33. Let’s Have
an Open
Forum

34. THANK
YOU!!!