Automotive Service

Automotive Service Modern Automotive Technology Study Guide for Chapter 75 Pages 1469 - 1492 Heating, Ventilation, & Air Conditioning 65 Points

Automotive Service • 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 • A ________________________ system, a ______________ system, • and a ___________________system are used to provide a comfortable passenger environment in all weather conditions. 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 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 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 • _______________________, 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 • When pressure is applied to a substance, its ________________ increases. • (the inverse is true also) Temperature Volume Displacement

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

Automotive Service • 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 Service 14-17. Refrigerant goes through four phases during the “refrigeration cycle”: C) ________________ C) __________________ E) ________________ E) __________________ (vaporization) Blue = Low Pressure Red = High Pressure Condensation Compression Start Here Expansion Evaporation

Automotive Service 18-21. The four basic parts of the A/C system are the: C) _________________________________ C) _________________________________ E) _________________________________ E) _________________________________

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Automotive Service 22-25. 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. Blower Receiver-Drier or Accumulator Refrigerant

Automotive Service 26. A/C’s 4 functions are to ________, _________________, ___________ and _________________ the air. Cool Dehumidify Clean Circulate

C. D. 4. F. E. 2. 1. 3. 5. A. B.

Expansion Valve Coolant Recovery Reservoir Evaporator Accumulator Blower Motor Radiator Water Pump Heater Core Cooling Fan Compressor Condenser

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

Automotive Service • The two major divisions of an A/C system are the __________ side and the • ________ side. High Side in the Engine Compartment Low Side in the Passenger Compartment

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

Automotive Service 30. The A/C compressor is engaged and disengaged by an electromagnetic _____. Clutch Crutch Dutch

Automotive Service • A very pure, highly refined, high-viscosity refrigerant _______ • circulates with refrigerant for lubrication. Water Coolant Oil

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

Automotive Service • The condenser, located in front of the _______________, • transfers heat to the outside, air. Headlights Radiator Back Seat

Automotive Service • The receiver-drier may be equipped with a __________ ___________ to • allow observation of refrigerant flow. It always has a desiccantinside to act • as a drying agent, removing moisture from the refrigerant.

Automotive Service • Compressors are actually piston pumps, similar to engines, and need a • _________________ to quiet them. Muffler Radiator Balancer

Automotive Service • An ___________ tube or an _________________ Valve control R-134a • 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, 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 Core Repeater Core Curriculum Core

Automotive Service 39. HVAC DUCTS & VENTS can be operated by ELECTRIC switches, mechanical LEVERS & CABLES, vacuum switches and motors or electronic control units like computers and sensors.

Automotive Service • Many vehicles now use a __________________ compartment air filter • known as a cabin air filter.

Automotive Service • ASE-Type Questions[pages1491 & 1492] • Circle your choice for the correct answer • A B C D AC theory • A B C D matter • A B C D conduction • A B C D heat transfer • 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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