Fiat 1998 Marea Weekend, Service Manual

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Marea-Marea Weekend
99 range
Auxiliary units
Climate control
50.
DENSO 7SB16 COMPRESSOR (engine 2387 JTD)
The compressor fitted on this version is the DENSO 7SB16 variable capacity swash plate type.
The capacity of the compressor varies between a maximum value (161.55 cc/rev) and a minimum value
(~8cc/rev) according to the thermal load in the climate control system: this feature makes it possible to
reduce the capacity (and consequently the power of the compressor) according to the refrigerant power
needed.
The alternating piston type compressor varies the capacity through the inclination of the rotary plate
(swash plate) which defines the piston stroke. The way the pistons are connected to the plate, which
identifies the technology, makes it possible to have a single plate which turns and guides the pistons with
the advantage of reducing vibrations, noise and torque fluctuations.
The variation of the capacity is achieved via an adjustment valve which balances the pressure inside the
compressor casing according to the compressor inlet and outlet pressure. The balancnig of the forces due
to the pressure makes it possible to adjust the angle of the plate and, consequently, the capacity. The
maximum capacity is obtained with the plate in the maximum inclination position whilst when the plate is
virtually vertical the capacity is minimal. The compressor is started up at minimum capacity thanks to a
special spring.
Operation
The motion is transmitted by the auxiliary shaft belt to the pulley (9) and, consequently, when the electro-
clutch is activated, to the shaft (1). The rotary motion is transformed into a rectilinear motion of the pis-
tons (4), via the plate (2) which is in one piece with the shaft and slides on the piston runners (3). The
adjustment valve (6) controls the capacity so that the intake pressure is as desired. The spring (8) returns
the plate to the minimum capacity position when the compressor is deactivated. The muffler (5) reduces
the intake gas impulses and consequently the noise and vibrations.
1. Shaft 6. Valve
2. Plate 7. Swash plate mechanism
3. Pad 8. Minimum capacity spring
4. Piston 9. Pulley
5. Intake muffler
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