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Automotive Service Modern Auto Tech Study Guide Chapter 75 Pages 1469 1492 Heating, Ventilation, & Air Conditioning 65 Points
Automotive Service 1. The term “air conditioning” generally means controlling the _______________,
______________, and flow of air in the passenger compartment of a vehicle.
Temperature, Humidity Temperature, Circulation Temperature, Direction
Automotive Service 2. A ________________________ system, a ______________ system,
and a ___________________system are used to provide a comfortable passenger environment in all weather conditions. (HVAC)
Refrigeration Heating Ventilation
Automotive Service 3. To learn refrigeration principles, the 3 states of matter, _________,
_____________, and ______ (vapor) must be understood. Also know that: HEAT is the controlling factor in the states of matter.
Automotive Service 47. Heat always moves from ____________ to ____________ objects
and is transferred in three ways:
___________ is heat transfer through objects touching each other
___________ is heat transfer caused by air moving past surrounding objects
___________ is heat transfer commonly caused by infrared (invisible) waves
From Hotter to Colder
From More Heat Toward Less Heat
Automotive Service 8. The ______________ ________________ ________ (Btu) is the unit for
measuring the quantity of heat transfer from one object to another. Degrees of temperature are our method of measuring heat intensity.
Bonus Thermal Unit British Thermal Unit Bahamas Thermal Unit
Automotive Service 9. _______________________ & ____________________ generally refer to
liquid changing into a vapor. Heat is absorbed to make this change. Absorbing heat boils refrigerant just like absorbing heat boils water in a kettle.
Vaporization & Evaporation Vaporization & Condensation Condensation & Evaporation
Automotive Service 10. _______________________, the opposite of vaporization, is when a vapor
changes back into a liquid. Heat is given off when this change is made.
Refrigeration Condensation Ventilation
Automotive Service 11. When pressure is applied to a substance, its ________________ increases.
(the inverse is true also)
Temperature Volume Displacement
Automotive Service 12. _______________ is the substance with a very low boiling point
that exchanges heat (is the refrigeration medium) in an A/C system.
Automotive Service 13. Both R____ and R________ are found in automotive A/C systems.
R12 is a CFC & is being phased out. R134a is a HFC
Automotive Service 1417. Refrigerant goes through four phases during the “refrigeration cycle”:
C) ________________ C) __________________ E) ________________ E) __________________ (vaporization)
Compression
Condensation
Evaporation
Expansion
Blue = Low Pressure = Cold Red = High Pressure = Hot
Start Here
Refrigeration Cycle
Automotive Service 1821. The four basic parts of the A/C system are the:
C) ______________ C) ______________ E) ______________ E) ______________
Automotive Service 2225. In addition to the 4 basic parts to accomplish the basic refrigeration cycle,
______________________ circulates through the system,
a ____________ (fan) is used to circulate air, (motor & squirrel cage fan)
a _____________________ or an __________________ containing a desiccant, stores and removes moisture from the refrigerant
finally, some type of thermostatic switch cycles the compressor on and off to prevent evaporator freezing.
Refrigerant
Blower
ReceiverDrier or Accumulator
Automotive Service 26. A/C’s 4 functions are to ________, _________________, ___________
and _________________ the air.
Cool Dehumidify Clean Circulate
Compressor
Condenser
Expansion Valve Evaporator
Water Pump Radiator
Cooling Fan
Coolant Recovery Reservoir
Heater Core
Blower Motor
Accumulator
Automotive Service 27. VALVES, DUCTS, FLAPS, (moved by either vacuum motors or electric servos)
& SWITCHES are used to direct the air flow under the dash.
Automotive Service 28. The two major divisions of an A/C system are the __________ side and the
________ side.
Low Side in the Passenger Compartment
High Side in the Engine Compartment
Automotive Service 29. The high pressure/high temperature side is under the _____,
while the ______________ compartment is the area where the low pressure/low temperature side of the system operates.
Hood, Passenger Cabin, Passenger Roof, Passenger
Automotive Service 30.The Beltdriven A/C compressor is
engaged and disengaged by an electromagnetic _____.
Clutch Crutch Dutch
Automotive Service 31. A very pure, highly refined, highviscosity refrigerant _______
circulates with refrigerant for lubrication.
Water Coolant Oil
Automotive Service 32. Special highpressure (250 psi) refrigerant lines & _______ carry the
R12 or R134a through the system. Hoses Noses Roses
Automotive Service 33. The condenser, located in front of the _______________,
transfers heat to the outside, air.
Headlights Radiator Back Seat
Automotive Service 34. The receiverdrier may be equipped with a __________ ___________ to
allow observation of refrigerant flow. It always has a desiccant inside to act as a drying agent, removing moisture from the refrigerant.
Automotive Service 35. Compressors are actually piston pumps, similar to engines, and need a
_________________ to quiet them.
Muffler Radiator Balancer
Automotive Service 36. An ___________ tube or an _________________ Valve control R134a
flow through the evaporator.
Orifice Tube or Expansion Valve
Automotive Service 37. There are many types of switches used to control A/C operation,
both ______ & _______ pressure cutout switches as well as ambient temperature switches limit operation to prevent system damage.
Low & High Crashing & Burning Freezing & Boiling
Automotive Service 38. The heating system uses a small, radiatorlike unit called the _________
_______ and the same squirrel cage fan & blower motor as the A/C system to circulate warm air through the passenger compartment.
Heater Core Repeater Core Curriculum Core
Automotive Service 39. HVAC _________ and __________can be operated by ELECTRIC switches,
mechanical LEVERS & CABLES, vacuum switches and motors or electronic control units like computers and sensors.
Ducks & Vents Ducts & Vents Deducts & Tents
40. Many vehicles now use a passenger compartment air filter known as a ________ air filter.
Automotive Service
Automotive Service ASEType Questions [pages1491 & 1492]
Circle your choice for the correct answer
1. A B C D AC theory
2. A B C D matter
3. A B C D conduction
4. A B C D heat transfer
5. A B C D evaporation
6. A B C D condensation
7. A B C D pressure
8. A B C D refrigerant