Iveco Daily Euro 4. Manual - part 221
52285
52286
Figure 5
Figure 6
The expansion (block) valve is located between the drier
filter and the evaporator.
Its function is to control and proportion the flow of
refrigerant fluid to get the highest refrigerating capacity out
of the system and to lower the pressure of the refrigerant (at
the filter outlet) to a pre-set value so that the fluid, circulating
in the evaporator, can be drawn up by the compressor in a
completely gaseous form.
The evaporator is a heat exchanger located between the
expansion valve and the compressor.
Its function is to:
- change the state of the refrigerant from a liquid, at the
inlet, to a gas, at the outlet;
- absorb the heat in the cab and thereby produce the
required refrigerating effect.
To be able to perform these functions, an electric fan draws
warm, moist air from the cab and conveys it onto the
evaporator.
Since this air is at a higher temperature than the refrigerant,
it gives some of its heat to the refrigerant and cools down,
while the moisture it contains condenses on the evaporator
fins in the form of droplets.
This produces cold, dehumidified air.
This change takes place with considerable heat absorption.
A special channel collects the condensation formed and
discharges it outside.
The considerable cooling of the radiating pack is due to the
change in state, from liquid to gas, of the refrigerant.
553233
Expansion valve
553231
Evaporator
This valve has two passages for the refrigerating fluid:
- the bottom one enabling the refrigerant to pass (5) from
the drier filter to the evaporator (2). Along this route
there is a spring (4) that, appropriately set, makes it
possible to obtain such a leap in temperature
(overheating) as to make sure that the refrigerant, at the
evaporator inlet, is entirely in its gaseous state. In
addition, there is also a modulating element, in this case
a ball (3) housed in the gauged pipe that controls the
flow rate of refrigerant to the evaporator;
- the top one enabling the refrigerant to pass (1) from the
evaporator to the compressor (6). Along this route
there is a temperature sensor (7) that, depending on the
temperature at the evaporator outlet, makes it possible
to control the flow rate of refrigerant, by means of the
modulating element (3), and control the overheating, by
means of the spring (4).
The drying filter is located between the condenser and the
expansion valve. On the vehicles equipped with the F1C
engine, it is incorporated into the condenser and performs
the following function:
- reserve tank for excess refrigerant fluid during variable filling
phases;
- filtering element for the solid particles generated by
compressor wear;
- eliminating the moisture formed in the system.
52284
Figure 7
553234
Drier filter
The condenser located in vehicles with F1C engine,
has the drier filter incorporated.
NOTE
When the vehicle is stationary or in a traffic jam, the flow of
air needed to transform the refrigerant fluid is produced,
under the control of the three-level pressure switch, by the
fan for cooling the engine coolant.
6
CAB AIR-CONDITIONING
D
AILY
E
URO
4