Fiat 1996 Brava Service Manual page 589

Auxiliary units Bravo-Brava
Manually operated climate control 98 range
50.
Compression mechanism
The contact between the compressor fixed scroll and the orbital scroll produces a chamber (1) in which
the gas is imprisoned with the volume tending to gradually decrease as the orbital scroll rotates. As
shown in the sequence illustrated, the compression chamber is alternately open for the supply of gas,
closed for transportation and open once again (at the outlet connector) for the discharge of the gas un­
der pressure.
The volume defined by the two scrolls decreases determining the compression mechanism for the gas
stored. The pressure gradually increases until the gas arrives at the centre zone where operating pres­
sure is reached; at this point thegas is released through the outlet connector to the condenser.
P4A18CH01
The sequence illustrates the different gas compression stages; the compression takes place after three
complete revolutions of the orbital scroll. Naturally, the cycle is continuous therefore the moment a
compression stroke takes place, a gas inlet stroke occurs simultaneously and the previous phase ends
with the escape of the gas under pressure.
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