Automotive ServiceModern Automotive TechnologyStudy Guide for Chapter 75 Pages 1469 - 1492Heating, Ventilation, & Air Conditioning65 Points

Automotive Service1. The term “air conditioning” generally means controlling the ___________________, ______________, and flow of air in the passenger compartment of a vehicle.

Temperature, HumidityTemperature, CirculationTemperature, Direction

Automotive Service2. A ________________________ system, a ______________ system, and a ___________________system are used to provide a comfortable

passenger environment in all weather conditions.

RefrigerationHeatingVentilation

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 4-7. 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 are our method of measuring heat intensity.

Bonus Thermal UnitBritish Thermal UnitBahamas 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 & EvaporationVaporization & CondensationCondensation & Evaporation

Automotive Service10. _______________________, the opposite of vaporization, is when a vapor changes back into a liquid. Heat is given off when this change is made.

RefrigerationCondensationVentilation

Automotive Service11. When pressure is applied to a substance, its ________________ increases. (the inverse is true also)

TemperatureVolumeDisplacement

Automotive Service12. _______________ is the substance with a very low boiling point that exchanges heat (is the refrigeration medium) in an A/C system.

Automotive Service13. Both R-____ and R-________ are found in automotive A/C systems. R-12 is a CFC & is being phased out. R-134a is a HFC

Automotive Service14-17. Refrigerant goes through four phases during the “refrigeration cycle”:

C) ________________ C) __________________E) ________________ E) __________________ (vaporization)

Compression

Condensation

Evaporation

Expansion

Blue = Low PressureRed = High Pressure

Start Here

Automotive Service18-21. The four basic parts of the A/C system are the:

C) _________________________________C) _________________________________ E) _________________________________E) _________________________________

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Automotive Service22-25. 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

and finally, some type of thermostatic switch cycles the compressor on & off to prevent evaporator freezing.

Refrigerant

Blower

Receiver-Drier or Accumulator

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Automotive Service26. A/C’s 4 functions are to ________, _________________, ___________ and _________________ the air.

CoolDehumidifyCleanCirculate

A.

B.

C.

D.

1.2.

3.

4.

5.

E.

F.

Compressor

Condenser

Expansion Valve

Evaporator

Water PumpRadiator

Cooling Fan

Coolant RecoveryReservoir

Heater Core

Blower Motor

Accumulator

Automotive Service27. VALVES, DUCTS, FLAPS, (moved by either vacuum motors or electric servos) & SWITCHES are used to direct the air flow under the dash.

Automotive Service28. The two major divisions of an A/C system are the __________ side and the ________ side.

Low Side in thePassenger Compartment

High Side in theEngine Compartment

Automotive Service29. The high pressure/high temperature side is under the HOOD, while the PASSENGER compartment is the area where the low pressure/low temperature side of the system operates.

Automotive Service30. The A/C compressor is engaged and disengaged by an electromagnetic _____.

ClutchCrutchDutch

Automotive Service31. A very pure, highly refined, high-viscosity refrigerant _______ circulates with refrigerant for lubrication.

WaterCoolantOil

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Automotive Service32. Special high-pressure (250 psi) refrigerant lines & _______ carry the R-12 or R-134a through the system.

Hoses

Automotive Service33. The condenser, located in front of the _______________, transfers heat to the outside, air.

HeadlightsRadiatorBack Seat

Automotive Service34. The receiver-drier 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 Service35. Compressors are actually piston pumps, similar to engines, and need a _________________ to quiet them.

MufflerRadiatorBalancer

Automotive Service36. An ___________ tube or an _________________ Valve control R-134a flow through the evaporator.

Orifice Tube or Expansion Valve

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Automotive Service37. 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 & HighCrashing & BurningFreezing & Boiling

Automotive Service38. The heating system uses a small, radiator-like 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 CoreRepeater CoreCurriculum Core

Automotive Service39. HVAC DUCTS & VENTS can be operated by ELECTRIC switches, mechanical LEVERS & CABLES, vacuum switches and motors or electronic control units like computers and sensors.

40. Many vehicles now use a __________________ compartment air filter known as a cabin air filter.

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ASE-Type 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

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