Refrigeration – Automatic control – Refrigeration producer
Reexamination Certificate
2001-11-09
2003-09-09
Wayner, William (Department: 3744)
Refrigeration
Automatic control
Refrigeration producer
C062S229000
Reexamination Certificate
active
06615600
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a controlling apparatus and a controlling method for a mode change type refrigerating system, particularly, to the controlling apparatus and the controlling method for the mode change type refrigerating system allowing the most appropriate temperature control even with respect to various heating loads.
2. Description of the Related Art
FIG. 4
is a diagram showing the schematic configuration of the whole of an air-conditioning system. The air-conditioning system is mounted, for example, on a motor vehicle. As shown in
FIG. 4
, an evaporator
51
cools the room air of the motor vehicle when a fan
52
is blowing. A variable capacity type gas compressor
10
compresses refrigerant gas to a condenser
53
.
When the refrigerant gas is liquefied, the condenser
53
emits the heat absorbed from inside the motor vehicle to outside of the motor vehicle. An expansion valve
54
rapidly reduces pressure of refrigerant gas from high pressure to low pressure. Since shaft power of an engine
59
is transferred to a rotating shaft
11
of the variable capacity type gas compressor
10
via a belt
63
, the rotating shaft
11
is rotatably driven.
FIG. 5
is a sectional view showing the variable capacity type gas compressor
10
.
FIG. 6
is a sectional view showing the variable capacity type gas compressor
10
taken along the
6
—
6
line in FIG.
5
. An inlet
1
of the variable capacity type gas compressor
10
intakes refrigerant gas from the evaporator
51
externally connected therewith. A cylinder
3
is inserted between a front head
5
and a rear side block
7
. A rotor
9
is rotatably provided in the cylinder
3
.
The rotor
9
is fixed through the rotating shaft
11
. On the periphery of the rotor
9
, vane grooves
13
are formed in a radial direction. Vanes
15
are slidably provided in the vane grooves
13
. When the rotor
9
rotates, the vanes
15
are biased toward an inner wall of the cylinder
3
due to centrifugal force of the rotor
9
and oil pressure of the bottom section of the vane grooves
13
.
The cylinder
3
is divided into a plurality of small chambers by means of the rotor
9
, the vanes
15
,
15
. . . . These small chambers are referred to as compression chambers
17
,
17
. . . . The capacity of the compression chambers
17
,
17
. . . alternately increases and decreases in accordance with rotation of the rotor
9
.
When the capacity of the compression chambers
17
,
17
. . . is changed with rotation of the rotor
9
, low pressure refrigerant gas is drawn in through the inlet
1
and compressed due to the change in the capacity. A case
19
is fixed on the surrounding end portion of the cylinder
3
and the surrounding end portion of the rear side block
7
. A discharge chamber
21
is formed inside this case
19
.
The high pressure refrigerant gas compressed at the compression chamber
17
is delivered into the discharge chamber
21
through a discharge port
23
and a discharge valve
25
. Further, the refrigerant gas is delivered into the condenser
53
via a discharge opening
27
from the discharge chamber
21
.
The variable capacity type gas compressor
10
is provided with a variable capacity mechanism
30
. The variable capacity mechanism
30
makes it possible to make the discharge capacity of the refrigerant gas variable by the room temperature of the motor vehicle.
FIG. 7
shows an example of the configuration of the variable capacity mechanism
30
.
A control board
29
is provided in the front head
5
facing the side portion of the cylinder
3
. The control board
29
includes two notches
29
a
. These notches
29
a
allow the interior of the cylinder
3
and an inhalation chamber
31
connecting to the inlet
1
to be communicated with each other. On the other hand, the compression chamber
17
is formed at the portion without the notch on the control board
29
, that is, the space closed by the inner wall of the cylinder
3
and the vanes
15
.
When the control board
29
is rotated to the right, the notches
29
a
are also rotated to the right, so the position where the compression chamber
17
is formed also moves to the right side. At this time, the capacity of the compression chamber
17
is accordingly reduced. In this way, the discharge volume is adjustable by rotating the control board
29
.
A driving shaft
39
for driving oil pressure performs a rotation of the control board
29
via a pin
33
. By adjusting the opening of a control valve
37
, oil is poured into a sleeve
35
from the discharge chamber
21
. The driving shaft
39
is moved forthrightly by the oil pressure due to the oil pressure generated at this time. This forthright motion of the driving shaft
39
is transformed into a rotary motion via the pin
33
to rotate the control board
29
. The injection volume of oil is adjustable by changing the opening of the control valve
37
. This adjustment of opening of the control valve
37
is implemented by changing a capacity control instruction value (duty ratio) shown in FIG.
8
. Then the control board
29
is rotated in proportion to elastic force by a spring
38
, according to a pressure difference between control pressure P
c
in the sleeve
35
and pressure P
s
in the inhalation room
31
.
In
FIG. 4
, a temperature sensor
55
is provided, for example to detect air temperature of an exit of the evaporator
51
. A rotating speed sensor
57
is provided to detect rotating speed of an engine
59
.
A control circuit
61
calculates the capacity control instruction value based on the detecting signal of this temperature sensor
55
and the rotating speed of the engine
59
. An occurrence circuit of capacity control signal
65
amplifies the signal of the capacity control instruction value to transfer it to the control valve
37
of the variable capacity mechanism
30
.
The controlling method of this variable capacity mechanism
30
will be described with reference to a flowchart shown in FIG.
9
. To simply describe the mechanism, the example given below refers to the case where the capacity of the variable capacity type gas compressor
10
is reduced when, for example, the rotating speed of the engine
59
is increased.
Here, it is assumed that a detected temperature of the exit of the evaporator
51
is lower than a target temperature
67
of the exit of the evaporator
51
. In this case, cooling capacity of the motor vehicle has to be lowered to prevent the room temperature of the motor vehicle from dropping excessively.
First, at step
1
(hereinafter abbreviated as “S
1
” in the drawing), the target flow rate of refrigerant of the variable capacity type gas compressor
10
is calculated based on a temperature deviation between target temperature and the detected temperature. PID control or the like is applied to this calculation.
At step
3
, the discharge volume of the variable capacity type gas compressor
10
is calculated from this calculated target flow rate of refrigerant, taking into consideration the rotating speed of the variable capacity type gas compressor
10
or the rotating speed of the engine
59
.
At step
5
, a calculation of rotating speed revision is performed from this discharge volume, based on a characteristic curve representing the relation between the discharge volume and the capacity control instruction value (not shown). The capacity control instruction value for the opening of the control valve
37
to be adjusted is determined by this calculation. In this case, the capacity control instruction value is small. As a result, at step
7
, an average current becomes smaller. Then at step
9
, the opening of the control valve
37
becomes smaller.
At this time, at step
11
, the control pressure P
C
in the sleeve
35
becomes smaller. Therefore, at step
13
, the driving shaft
39
moves downward. At step
15
, the control board
29
rotates in the right-hand direction. As a result, at step
17
, the discharge volume of the variable capacity type gas compressor
10
becomes smaller, and the cooling c
Shi Yongwei
Shimada Akira
Adams & Wilks
Seiko Instruments Inc.
Wayner William
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