This document provides an overview of automotive air conditioning systems for a vocational training presentation. It defines an automobile and briefly outlines the history of General Motors. It then describes the layout of a GM workshop and defines the key components of an automotive AC system, including the compressor, condenser, receiver/dryer, thermal expansion valve, evaporator, and refrigerants. The roles and functions of each component are explained. In conclusion, it emphasizes the importance of using environmentally friendly refrigerants and properly disposing of and recharging AC systems.

1. A VOCATIONAL TRAINING PRESENTATION
ON
MEGHA AUTO WORK SHOP
LUCKNOW
In partial fulfilment of the requirement for the Degree of
BACHELOR OF TECHNOLOGY
to Department of Mechanical Engineering
Submitted By: Alok Kumar Singh
Roll No: 1343140013

2. Content
 What is Automobile ?
 GM History
 GM in India
 Layout of Megha Chevrolet Workshop
 Automotive A/C systems
 Why A/C system used?
 Parts of A/C system
 Refrigerants
 Conclusion

3. What is Automobile ?
 Automobile is a
transportation means on
road , consisting of four
wheel and powered by an
engine. Automobile
generally use gasoline to
fuel the internal engine,
technological advance have
led to the design of cars
that run on electricity.

4. GM History
 General Motors was capitalized by William C. Durant on
September 16, 1908 as a holding company.
 In 1918 GM acquired the Chevrolet stock from
McLaughlin Motor Car of Oshawa, Ontario, Canada,
manufacturer of the McLaughlin automobile since 1907
and later to be renamed by McLaughlin-Buick.
 GM's headquarters were located in Flint until the mid-
1920s when it was moved to Detroit.
 In 2008, 8.35 million GM cars and trucks were sold globally
under various brands.

5. GM in India
 GM started its Indian journey in 1996 and offers products
under the Chevrolet brand in the country. Its flagship
brand, Chevrolet, was introduced in India in 2003, under
the banner "For a Special Journey Called Life".
 Headquartered at Gurgaon, GM India presently makes
the Chevrolet Spark, Chevrolet Beat, Chevrolet Sail,
Chevrolet Sail Hatchback, Chevrolet Cruze, Chevrolet
Enjoy, Chevrolet Tavera, Chevrolet Captiva for the Indian
market.
 General Motors Technical Centre is Located in Bangalore,
it houses the Design Studio and the Engineering centre. It
is actively involved in Design, Analysis and Development of
vehicles and Propulsion Systems both globally and for the
Indian market.

7. Washing
Area
Wheel
Alignment
Suspension
Repairing
Engine
Repairing
Body
Shop
Paint
Booth
Unit
Repair
Shop
Reception
& Waiting
Area
Stock
Room
Tool
Room
Inspection Bay
Parking
Parking
W
S N
E
Layout of Megha Chevrolet

8. Automotive A/C systems
 Basic understanding of the system, the components
and the roles they play.

9. Why A/C system used?
 Automobile air conditioning (also called A/C) systems use
to cool the air in a vehicle.
 Stopped in traffic on a may afternoon.
 Sweat drips all over your body.
 Hands feel like they are about to slip away from the steering
wheel due to sweat.
 Need a luxurious and a comfortable ride.

10. Understanding the system.
 The A/C system is nothing more than a heat exchanger.
 The main function of A/C system is to cool and remove
humidity from air inside the car.
 There are only 6 major parts to the system.
• Compressor
• Condenser
• Receiver/Dryer
• Thermal Expansion Valve
• Evaporator
• Refrigerant

11. Typical A/C System and Flow.

12. Compressor
 It is a pump driven by a belt attached to the engine’s crankshaft .
 Puts the refrigerant gas under pressure and forces it to the
condenser.
 It cant compress liquids, only gases.
 By increasing the pressure the refrigerant gas leaving the
compressor becomes hot.
 Also called as heart of the air
Conditioning system.

13. Compressor Clutch
The compressor Clutch has three major components.
• Coil
• Pulley
• Clutch

14. Condenser
 Its location is usually in front of the radiator.
 Identified as second radiator of the car that shares air flow
with main radiator.
 It converts vapour into liquid with constant pressure and
temperature.
 It has own cooling fans that become active when AC is on.
 Takes up the heat from the high pressure refrigerant gas and
cools it.
 Condensing of the refrigerant gas causes it to loose heat and
form into a liquid.
 Heat is expelled into the atmosphere by the air flowing from
the cooling fans.

15. Receiver/Dryer
 After condensation, the liquid refrigerant is stored in
Receiver/Dryer.
 Main function is to remove moisture and other contaminants
from the cool refrigerant liquid.
 Contains small granules called desiccants that attract water.
 If water is not removed, it can form ice
 crystals, thereby damaging the whole
 system.

16. Thermal Expansion Valve
 Here the pressure of refrigerant is reduced causing expansion
of the liquid, resulting in further cooling.
 Slowly the liquid reverts back into a gaseous form.
 Also the valve reduces pressure on the refrigerant so it can
easily move into the evaporator.
 The valve senses pressure and regulates
the flow of refrigerant, which allows
the system to operate steadily.

17. Evaporator
Evaporator serves as the heat absorption component.
 A primary duty of Evaporator is to remove heat from the
inside of the vehicle.
 A secondary benefit is dehumidification.
Refrigerant gas enters the evaporator coils and absorbs the
heat inside the car’s cabin and moves out of the coils.
A fan blowing over the outside of the evaporator coil
blows cool air into the passenger compartment.
Thus the evaporator takes humidity out
 of the air in the car, which
 helps you feel cool.

18. Refrigerant
There are two types of refrigerants used in automotive
applications.
• Freeze-12
• R-134a

19. R-134a Refrigerant
Advantage Disadvantage
• Normally non flammable.
• Ozone friendly.
• Non toxic.
• Changes state easily at low
temperature.
• Soluble with oil.
• Low boiling point.
• Stays as a liquid under
pressure.
• Smaller molecular size
than R12.
• More hydrophobic than
R12.
• Adds slightly to global
warming 0.03.

20. Conclusion
 An AC system not only cools the cabin, it removes dust and
dirt, leaving only with fresh air.
 One has to remember to use only environment friendly
refrigerants and avoid CFCs as much as possible.
 The AC system can be recharged by adding fresh refrigerant
and removing the remaining one.
 Care must be taken in the disposal of refrigerants as they may
affect the soil, rivers, etc.,
 Its also necessary to check the AC system for leaks as it may
lead to the loss of refrigerant as well as environmental hazards.

21. Thank you…
Anyways, let us minimize the usage of ACs and go green!