NANO

838

HVAC

Operation:

Whenever the engine is operating, the pulley is rotating

since it is connected to the crankshaft by a belt, but

the compressor does not operate until the clutch is

energized. When the air conditioning system is

switched ON, the ECU generates a signal for

energizing the compressor. The electromagnet attracts

the pressure plate and pulls the plate against the friction

facings on the pulley. The friction between the facing

and plate causes the clutch assembly to rotate as a

unit, and drive the compressor.

COMPONENT DESCRIPTION OF HVAC /

A/C SYSTEM :

Compressor

It is the heart of A/C system specially designed to

compress the refrigerant. The compressor draws

vaporized refrigerant from the evaporator. It compresses

the refrigerant (resulting into temperature rise of

refrigerant) and the refrigerant will be passed onto

condenser for condensation.

Compressor relay

Compressor relay is located in fuse box which is used

to operate the compressor magnetic clutch. The

magnetic clutch continues to operate as long as air

conditioner is under operation. Once the air conditioner

is put in OFF condition, the compressor relay gets

cut off and the magnetic clutch gets disengaged from

the compressor. The cut - in and cut - off of relay is

governed by ECU.

Magnetic clutch

A magnetic clutch is used to connect and disconnect

the compressor from the engine.

Main components are stator, rotor, and pressure plate.

Principle:

When the current is fed to the coil (as shown fig. on

the right), magnetic force is generated in iron II which

attracts iron I.

Construction:

A magnetic clutch consists of a stator, rotor with

pulley, and pressure plate to engage the drive pulley

and compressor magnetically. The stator is fixed on

the compressor housing, and the pressure plate is

attached to the compressor shaft. Two ball bearings

are used between the inner surface of the rotor and

the front housing of the compressor.