JPH03233280A - Device for controlling defrosting of freeze refrigerator - Google Patents

Abstract

PURPOSE:To minimize temperature rise in a refrigerator due to defrosting operation by stopping defrosting operation as soon as either the detected temperature of a defrosting temperature detector has reached a first defrosting completion time or that of a refrigerator detector has reached a second defrosting completion temperature. CONSTITUTION:As soon as either defrosting temperature Tf detected by a defrosting temperature detector 9 of a cooler 4 has reached a first defrosting completion temperature T1 or temperature Tr in a refrigerator detected by a refrigerator temperature detector 7 of a freezer 2 has reached a second defrosting completion temperature T2, defrosting operation is stopped. That is, when Tf exceeds T1 earlier, it is decided that large amount of frost attached to the cooler 4 has been removed and when Tr has exceeded T2, lower than T1, earlier, it is decided that some quantity of frost has been rapidly removed, as in the case of low load operation, and the temperature in the refrigerator has rapidly increased due to the heat of a heater 6, so that the defrosting operation is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a defrosting control device for a refrigerator-freezer that automatically defrosts a cooler.

[Prior Art] Fig. 4 to Fig. 6 show a conventional defrosting control device for a refrigerator/freezer disclosed in, for example, Japanese Unexamined Patent Publication No. 63-282469. FIG. 6 is a flowchart showing the control operation thereof. In the figure, (1) is the refrigerator body, and the inside is the freezer compartment (2).
It is partitioned into a plurality of storage rooms, such as a refrigerator and a refrigerator (3).

(4) is a cooler installed in the back of the freezer compartment (2), (5)
) is the fan motor installed above it, (6) is the defrost heater that removes the frost attached to the cooler (4), (7)
is an internal temperature detector that detects the temperature inside the freezer compartment (hereinafter referred to as internal temperature), and (8) is a variable resistor attached to the front of the refrigerator body (1) (on the door of the freezer compartment (2), etc.). (9) is a defrost temperature sensor installed on the upper side of the cooler (4) and detects the surface temperature (hereinafter referred to as defrost temperature) of the cooler (4); (10) is a defrost temperature sensor installed at the bottom of the main unit. (11) is the compressor installed in the temperature sensor (
7), variable resistor (8), defrost temperature detector (9), etc., the fan motor (5) and defrost heater (
6), a control circuit unit that controls the compressor (10), etc.;
2) is an AC power supply, (13) is a resistor connected in series with the internal temperature detector (7), (14) is a resistor connected in series with the internal temperature setting device (8), (15) is a resistor connected in series with the defrost temperature sensor (9), (16) is a microcomputer (hereinafter simply referred to as microcomputer), (16a) is a timer built in microcomputer (16), (17) ), (18).

(19) is a drive circuit for the fan motor (5), compressor (10) and defrost heater (6), (20), (21)
, (22) are these drive circuits (17), (18)
, (19), a relay coil controlled by (20)
a), (21a), and (22a) are normally open contacts of these relay coils (20), (21), and (22).

In the refrigerator-freezer control device configured as described above, when the compressor (]0) is operated, the refrigerant circulates, and the cold air cooled by the cooler (4) is circulated as the fan motor (5) rotates. and circulate through each storage chamber as shown by the arrows in FIG. At that time, the compressor (10) and fan motor (5) are operated intermittently to maintain the internal temperature at the set temperature,
Furthermore, when the accumulated operating time of the compressor (10) is reached, the defrost heater (6) is energized and the cooler (4) is defrosted.

Next, details of the above-mentioned control operation will be explained according to the flowchart of FIG. The subroutine shown in FIG. 5 is stored in the microcomputer (16) of the control circuit section (l). First, start with the internal temperature setting device (8) and the resistor (1).
The voltage at the connection point 4) and the voltage at the connection point between the internal temperature detector (7) and the resistor (13) are input to the microcomputer (16) and A/D converted into digital values.

The set temperature Ts and internal temperature Tr are read respectively (
Step (23)). These read surface temperature values Ts,
Tr are compared in step (24). At this time.

If the internal temperature Tr is below the set temperature Ts, the compressor operation command flag F1 is set to 0 in step (25), and the relay coils (20) and (21) are deenergized in step (26) and the fan motor is turned off. (5) and compressor (10) are stopped. Next, the internal temperature Tr rises and the set temperature Ts
If the above is reached, step (z4) to step (27)
The compressor operation command flag F□ becomes 1, and in step (28), the microcomputer (16) sends a message to the drive circuit (17).
, Da), and the relay coil (20
) and (2r) are energized, and the fan motor (5) and compressor (10) are operated. As a result, cold air is supplied into the refrigerator, and the temperature Tr in the refrigerator decreases. While the compressor (10) is operating, the operating time of the compressor (10) is checked in step (29) by the built-in timer (
It is integrated in step 16a), and it is determined in step (30) whether the integrated time t exceeds a predetermined time X. Here, if the cumulative operating time t has not reached the predetermined time X, the defrost start flag F2 is 0, and step (3)
Step 5) returns to the main routine, and the above operations are repeated until the cumulative operating time reaches the predetermined time X. Compressor (
10) When the cumulative operating time t reaches the predetermined time X, steps (31), (32), (33), (34
), the defrosting start flag F2 becomes 1, and the timer (
16a) is reset, the compressor operation command flag F1 becomes 0, and the compressor (10) and fan motor (5) stop. Then, since F2=1 in step (35), the process proceeds to step (36), where the operation signal is output from the microcomputer (16) to the drive circuit (19), and the relay coil (2
2) is energized, the contact (22a) closes, and the defrost heater (
6) is supplied with a driving current from an AC power source (12).

When defrosting is started, in step (37), the voltage at the connection point between the defrosting temperature detector (9) and the resistor (15) is input to the microcomputer (16), and the A/D converted defrosting temperature Tf is read. In step (38), it is determined whether the defrosting temperature Tf is equal to or higher than the predetermined temperature T0, and the defrosting operation is continued until the defrosting temperature Tf becomes equal to or higher than the predetermined temperature T1.
When □ is reached, the process proceeds to step (39), the relay coil (22) is deenergized, the contact (22a) is opened, the defrost heater (6) is turned off, and the defrost start flag F2 is set to O in step (40). This completes the defrosting operation and returns to the main routine. In this way, the compressor (10) is operated intermittently depending on the relationship between the set temperature Ts and the internal temperature Tr, and when the operating time t exceeds the predetermined time X, the cooler (4) is defrosted. . When the defrosting temperature Tf reaches a certain predetermined temperature T, the defrosting operation ends, the operation of the compressor (10) is restarted, and normal operation is repeated until the next cumulative operating time reaches a predetermined time.

[Problem to be Solved by the Invention] The conventional defrosting control device for a refrigerator-freezer is configured as described above, and the defrosting end temperature is detected only by the defrosting temperature detector, so the cooling load is small and the opening/closing of the door is easy. If the frequency of operation is small, when the compressor operating time reaches a predetermined time, the defrosting operation starts even though there is no amount of frost that would reduce the cooling capacity. Even if the temperature inside the refrigerator rises, the temperature of the defrosting temperature sensor is delayed until it reaches a predetermined value, which has a negative effect on the stored food.

This invention was made in order to solve the above-mentioned problems, and its purpose is to provide a defrosting control device for a refrigerator-freezer that can suppress the rise in internal temperature due to defrosting to a minimum and defrost reliably. do.

[Means for Solving the Problems] The defrosting control device for a refrigerator-freezer according to the present invention is provided when the temperature detected by a defrosting temperature detector that detects the temperature of a cooler reaches a first defrosting end temperature or when the temperature inside the freezer reaches a first defrosting end temperature. The defrosting end determination means sets the defrosting end condition to be when the temperature detected by the internal temperature detector reaches the second defrosting end temperature, or whichever is earlier.

[Function] The defrosting control device for a refrigerator according to the present invention performs the defrosting operation when either the temperature of the cooler reaches the first defrosting end temperature or the temperature inside the freezer reaches the second defrosting end temperature. ends.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
3 to 3 show an embodiment of the present invention, FIG. 1 is a schematic configuration diagram, FIG. 2 is a circuit configuration diagram thereof, and FIG. 3 is a flowchart showing its control operation. In the figure, (1
) is the refrigerator itself, (2) is the freezer compartment, (3) is the refrigerator compartment, (
4) is the cooler, (5) is the fan motor, (6) is the defrost heater, (7) is the internal temperature detector, (8) is the internal temperature setting device, (9) is the defrost temperature detector, ( 10) is a compressor,
(11) is the control circuit section, (12) is the AC power supply, (13)
, (14), (15) are resistors, (16) is a microcomputer,
(16a) is a timer, (17), (18),
(19) is a drive circuit, (20), (21), (
22) are relay coils, (20a), (21a)
.

(22a) is a normally open contact of these relays, which is similar to the conventional example described above. (16b) is a timer (
In addition to 16a), there is a defrosting completion determination program built into the microcomputer (16), and (41) is the internal temperature detector (7).
and compressor/fan motor drive control means for controlling on/off of the compressor (10) and fan motor (5) according to the temperature signal from the refrigerator temperature setting device (8); (42) is the compression 1;
1fi (10) and a timer means for counting and accumulating the operating time of the fan motor (5); (43) is a defrosting start determining means for emitting an output when the accumulated time by the timer means (42) reaches a predetermined value; (44) ) is a defrosting means that starts its operation in response to the output from the defrosting start determination means (43) and heats the cooler (4) to remove frost attached thereto; (45) is a livestock temperature detector; (9) and a defrosting completion determination means for terminating the operation of the defrosting means (44) at a time point corresponding to the temperature signal from the internal temperature detector (7).

Next, the detailed operation will be explained according to the flowchart of FIG. First, in step (23), the set temperature Ts and the internal temperature Tr from the internal temperature setting device (8) and internal temperature detector (7) are read. These read temperature values T s and Tr are compared in step (24),
If the internal temperature Tr is below the set temperature Ts, the compressor operation command flag F1 is 0 in step (25), and the fan motor (5) and compressor (10) are activated in step (26).
is off. Next, when the internal temperature Tr rises and becomes equal to or higher than the set temperature Ts, step (24) to step (2)
Proceeding to step 7), Fl becomes 1, and the fan motor (5) and compressor (10) are turned on in step (28). While the compressor (10) is in operation, the operating time of the compressor (10) is accumulated by the built-in timer (16a) in step (29), and whether or not the accumulated time t exceeds the predetermined time X is checked in step (30).
It is judged by. Here, if the cumulative operating time t has not reached the predetermined time The above operations are repeated. The cumulative operating time t of the compressor (10) is the predetermined time
When reaching , step (31), (32), (
33) and (34), and the defrosting start flag F2 becomes 1.
As a result, the timer (16a) is turned on and the compressor operation command flag F becomes 0, turning off the compressor (10) and fan motor (5). Then step (35)
Since F2=1, the process proceeds to step (36) and defrost heater (6) is turned on to start defrosting. At step (37), defrost temperature Tf from defrost n degree detector (9) and refrigerator The internal temperature Tr from the internal temperature detector (7) is read, and in step (38) the defrosting temperature Tf is set to the first
It is determined in step (46) whether the internal temperature Tr is higher than or equal to the second defrosting end temperature T1, which is lower than the first defrosting end temperature T, and whether any of them is higher than the first defrosting end temperature T is determined. Alternatively, the defrosting operation continues until the second defrosting end temperature T□ or 12 or higher is reached, and when the defrosting end temperature T or T2 is reached, the process proceeds to step (39), the defrost heater (6) is turned off, and step ( 40)
The defrost start flag F2 becomes 0, the defrost operation is completed, and the process returns to the main routine.

Note that in the flowchart in Figure 3, step (2)
3) to (28), (33), and (34) are compressor/fan motor drive control means (41) and step (29).
), (32) is the timer means (42), step (
30), (31), and (35) are the defrosting start determination means (4
3), steps (36) and (39) are the defrosting means (
44), steps (37), (38), (46
) and (40) are the defrosting completion determination means (45) and the defrosting completion determination program (16b).

In this way, the temperature inside the freezer (2) is detected when the defrost temperature Tf, which is the temperature detected by the defrost temperature detector (9) that detects the temperature of the cooler (4), reaches the first defrost end temperature T0. The internal temperature T, which is the temperature detected by the internal temperature detector
The defrosting operation ends when r reaches the second defrosting end temperature T2, whichever is earlier. That is, if Tf rises faster than the first defrosting end temperature 74, it is determined that a large amount of frost attached to the cooler (4) has been removed.
If the second defrost end temperature, which is lower than fJ < T It is determined that the temperature has risen, and the defrosting operation is stopped6. In the above embodiment, the first defrosting end temperature T
Although it is assumed that the defrosting temperature sensor (9) and the internal temperature sensor (7) are installed higher than the defrosting end temperature T2, T□>T2 does not necessarily have to be satisfied depending on the position.

[Effects of the Invention] As described above, according to the present invention, when the detected temperature of the defrosting temperature detector that detects the temperature of the cooler reaches the first defrosting end temperature, or the internal temperature that detects the temperature inside the freezer Since the defrosting end determination means is provided which sets the defrosting end condition when the temperature detected by the detector reaches the second defrosting end temperature or whichever is earlier, the temperature inside the refrigerator can be determined regardless of the number of cores of frost attached to the cooler. This has the effect of providing a defrosting control device for a refrigerator-freezer that can always perform an effective defrosting operation while suppressing an increase in the temperature.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing an embodiment of the present invention, Fig. 2 is a circuit diagram thereof, Fig. 3 is a flowchart showing its control operation, and Fig. 4 is a diagram showing a conventional refrigerator-freezer control device. FIG. 5 is a circuit diagram thereof, and FIG. 6 is a flowchart showing its control operation. In the figure, (1) is the refrigerator body, and (2) is the freezer compartment. (4) is a cooler, (5) is a fan motor, (6) is a defrost heater, (7) is an internal temperature detector, (8) is an internal temperature setting device, (9) is a defrost temperature detector, (10) is a compressor, (11) is a control circuit, (16) is a microcomputer, (1
6a) is a timer, (16b) is a defrosting completion determination program, (41) is a compressor/fan motor drive control means, (
42) is a timer means, (43) is a defrosting start determining means, (44) is a defrosting means, and (45) is a defrosting end determining means. The same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] a defrosting means for heating the cooler to remove frost attached thereto; a defrosting start determining means for detecting a predetermined defrosting start condition and starting a defrosting operation of the defrosting means; In the defrosting control device for a refrigerator-freezer, the defrosting control device is provided with a defrosting end determining means for terminating the defrosting operation of the means, and the defrosting end condition of the defrosting end determining means is set to a temperature detected by a defrosting temperature detector that detects the temperature of the cooler. Does it reach the defrosting end temperature of 1?
A defrosting control device for a refrigerator-freezer, characterized in that the temperature detected by an internal temperature detector for detecting the temperature inside the freezer reaches a second defrosting end temperature, whichever comes first.