Automobile Air Conditioning

8/18/2019 Automobile Air Conditioning

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AN INTRODUCTION TO

AUTOMOBILE AIR-

CONDITIONING(PRINCIPLE OF OPERATION AND CONTROL SYSTEMS)

Team :Ride and handling


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MAJOR FUNCTION OF

AUTOMOBILE AIR CONDITIONER

Human comfort:

Temperature – 220C to 260CHumidity – 40 to 60 %

NOTTEMPERATURE

ALONE….


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HOW DOES HEAT GET INSIDE

VEHICLE ?


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REFRIGERATION SYSTEM


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REFRIGERANT R-134A

R134a - TetrafluroethaneR134a was selected as a replacement refrigerant for R12

(Dichlorodifluoromethane) because R12 containing chlorine

has a major effect to ozone layer depletion.

Before 1996:

R-12

CFC-12

After 1996:

R-134a

HFC-134a


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COMPRESSOR

Clutch assembly


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AC WIRING

Control Wiring Layout


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COMPRESSOR CYCLING CONTROL & PROTECTION

DEVICES

Pressure cycling switch - Electrical

Protection Devices

Clutch Diode

Refrigerant

Pressure Switches:• Low pressure• High pressure


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SENSORS

Sun load sensor

Ambient temperature sensor

The sunload sensor is a photochemical diode(PCD) located on top of the dashboard.

This sensor sends a signal to the electrical

climate control module (ECCM) indicating

the strength of the sunlight (sunload) which

influences the vehicle interior temperature.

High sunload High blower speed Maximum cooling

Low sunload Low blower speed Moderate cooling

The ambient temperature sensor is a

negative coefficient resistor (NTC) with low

voltage input. The sensor alters resistance depending on

the ambient air temperature surrounding it. The sensor is located in the ambient air

stream normally behind the bumper bar or

front grille area. This sensor is used to monitor the outside

temperature and is interconnected to a

visual display in the instrument panel.


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OTHER COMPONENTS

Flow Control valve Condenser

Fan

Evaporator

Hose


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COMPRESSOR CYCLING CONTROL &

PROTECTION DEVICES

Engine Control Module ECM!

Bod" Control Module BCM!

#o$er Tr%in Module #CM!

These modules are used to engage and disengage the

compressor !eacti"ate the #$C compressor at high$low system

pressures%

!eacti"ate the #$C compressor at &ic&down% #cti"e and deacti"ate the condenser 'an%(ncrease engine idle speed when #$C system is acti"ated%!eacti"ate the #$C compressor at high engine RP)%!elay #$C compressor engagement at engine cran&ing%#cti"ate electrical engine 'an at predetermined coolant

temperature%!eacti"ate the #$C compressor when coolant temperature

e*cessi"e%!eacti"ate the #$C compressor at wide open throttle

+,T.


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HVAC

H/#C is pro"ided to heat or cool the en"ironment in the "ehicle and to ensure

a good through-'low o' 'resh0 clean air 'or passenger com'ort and dri"er

alertness

#ir heating process #ir cooling process


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SENSOR LOCATIONS


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SYSTEM OVER VIEW OF ELECTRONICALLY

CONTROLLED AIR CONDITIONER


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SYSTEM OPERATING PRINCIPLE


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LEAK DETECTION

Method of leak detection

1.Visual leak detection

2.Soap solution

3.Electronic leak detector

4.Ultraviolet fluorescent system


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THANK YOU

Documents

Automobile Air Conditioning