JPH0760047B2 - Cooling control device for refrigerator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a control rule of a rapid cooling control device based on an empirical rule for cooling foods to an appropriate temperature in a short time, and a membership function of fuzzy variables constituting the control rule. The present invention relates to a quenching control device for a refrigerator that infers an optimal operation amount of a quenching fan by using and outputs the result.

2. Description of the Related Art Refrigerators (including refrigerators / freezers) have a basic function of storing foods and the like, but in recent years, those with additional functions have begun to appear. One of the additional functions is rapid refrigeration (hereinafter abbreviated as rapid cooling). This rapid cooling is used to cool food to an appropriate temperature as needed, and it can be used when, for example, "I want to quickly cool beer with a quick customer" or "I want to eat a salad with a quick cooling". It has the advantage of being able to preserve the freshness as it is at a speed.

In a conventional refrigerator quenching control device, for example, Japanese Patent Laid-Open No. 63-11
There is a method shown in Japanese Patent No. 8584. Here, when the rapid cooling is started by a rapid cooling command (for example, switch-on), the damper is always opened for a preset time, and the fan continuously sends the cool air to the rapid cooling chamber. However, in such a method of controlling the rapid cooling operation only depending on time, there is a problem that, for example, a beer bottle bursts due to supercooling, or other foods freeze and their quality deteriorates. In order to solve this supercooling, there is a method as disclosed in, for example, JP-A-63-189760. That is, in the rapid cooling state, the damper is used to set the temperature of the quenching chamber to a temperature lower than usual, and the internal cool air is forcedly circulated using the fan to cool the food,
Non-contact the surface temperature of the food (eg infrared sensor)
The rapid cooling operation was stopped when the surface temperature cooled to a certain temperature.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in such a configuration, since the cooling is always performed with a constant cooling capacity during the rapid cooling, even if the rapid cooling operation is stopped at the target surface temperature, for example, the rapid cooling progresses further with the aftereffect. The temperature will be lower than the target temperature (generally called overshoot). Moreover, since the temperature control is only performed after the completion of the rapid cooling, the temperature once lowered does not return to the normal temperature. In this case, the worst condition such as bursting of the beer bottle can be avoided, but since the supercooling still occurs and the low temperature condition continues for a while, there is a fear that the food is frozen and the quality is deteriorated. Further, since the temperature of the food is lower than the optimum temperature, the flavor and taste of the food are impaired.
In order to prevent this, for example, it is conceivable to set the target surface temperature to a higher level, but in this case insufficient cooling will occur, and only the surface will be cold and the contents will not be cold. There was a problem that the flavor and taste of the product would be impaired.

In view of the above problems, the present invention provides a quenching control device for a refrigerator that does not deteriorate the quality such as freezing of food, does not impair the flavor and taste of food, and can reach a target temperature in a short time. The purpose is to

Means for Solving the Problems In order to achieve the above object, the quenching control device for a refrigerator of the present invention is a food temperature detecting means for detecting the temperature of food or the like placed in a quenching chamber, and the output of the food temperature detecting means. And a memory device that stores a control rule based on an empirical rule for obtaining the operation amount of the quenching fan, with respect to the information of the output of the food temperature detecting means and the output of the differentiating means, A fuzzy inference means for performing a fuzzy logic operation to calculate the operation amount of the quenching fan based on the output of the food temperature detecting means, the information of the output of the differentiating means, and the control rule extracted from the memory device. It is characterized by having.

Action According to the present invention, the operation temperature of the quenching fan with respect to the food temperature detected by the food temperature detecting means and its change amount are calculated based on the control rule obtained from the empirical rule, so that the present invention is rapidly cooling. Depending on the condition of the food, such as when it begins to cool or just before the end of quenching, the cooling fan will perform the optimal cooling so that the food can always be cooled with the optimal cooling capacity. The shortage can be prevented.

Embodiment A quenching control device for a refrigerator according to an embodiment of the present invention will be described below with reference to the drawings.

First, the schematic structure of the present invention will be described with reference to FIG. FIG. 2 is a sectional view of the refrigerator of the present invention. In FIG. 2, reference numeral 1 denotes a refrigerator main body, which is composed of an outer box 2, an inner box 3 and a urethane foam heat insulating material 4 formed in a space between them.
Three doors 5, 6, 7 are arranged in the front opening.
The doors 5, 6, and 7 are arranged corresponding to the openings of the freezer compartment 8, the refrigerator compartment 9, and the vegetable compartment 10 of the refrigerator body 1, respectively.
Inside the partition wall surrounded by the bottom plate 11 of the freezer compartment 8 and the top plate 12 of the refrigerating compartment 9, there is an evaporator 13 and an internal fan 14 behind it. Further, ventilation paths 15 and 16 for introducing cooling air from the evaporator 13 into the respective compartments are formed at the backs of the freezing compartment 8 and the refrigerating compartment 9. 17 is a compressor. Reference numeral 18 is a quenching room provided below the refrigerating room 9. The quenching chamber 18 is separated from the refrigerating chamber 9 by a wall 19, and a door 20 is arranged at the opening thereof. An air passage 21 for introducing cold air from the evaporator 13 into the quench chamber 18 is formed on the back surface of the quench chamber 18.

The configuration of the quenching device in the refrigerator thus configured will be described in more detail with reference to FIG. First
FIG. 1 is a block diagram of a quenching control device for a refrigerator according to the present invention. In FIG. 1, reference numeral 22 is a damper for introducing or blocking cold air from the ventilation passage 21. Reference numeral 23 is a quenching fan for introducing cold air into the quenching chamber 18. The cool air referred to here includes the first cool air supplied through the ventilation passage 21 and the damper 22, and the second cool air supplied through the ventilation hole 24 provided at the rear portion of the top surface of the wall 19. The first cold air is about −18 ° C., and the second cold air is about 5 ° C.
Reference numeral 25 is a food temperature sensor for detecting the surface temperature of the food 26. 27 is a food temperature detecting means for detecting the surface temperature T of the food 26 from the output of the food temperature sensor 25. Reference numeral 28 is a differentiating means for differentiating the output of the food temperature detecting means 27 to calculate a change amount ΔT of the surface temperature of the food 26 (that is, ΔT = T (t + Δt) -T (t)). Further, 29 is a microprocessor, which comprises a fuzzy inference means 30 and a memory device 31 for storing control rules. 32 is fuzzy reasoning means 30
The quenching fan control means controls the capacity (that is, the number of revolutions) of the quenching fan 23 in accordance with the instruction of the operation amount obtained in (3). 33
Is a quenching chamber temperature sensor that detects the temperature inside the quenching chamber 18. Reference numeral 34 is a quenching chamber temperature detecting means for calculating the temperature of the quenching chamber 18 based on a signal from the quenching chamber temperature sensor 33. Reference numeral 35 is a damper control means for controlling the opening / closing of the damper 22 according to the output of the quenching room temperature detection means 34.

The operation of the refrigerator quenching control device configured as described above will be described below with reference to FIGS. 1 to 5.

The food temperature detecting means 27 detects the surface temperature T of the food 26 from the output of the food temperature sensor 25, and the differentiating means 28 differentiates the output of the food temperature detecting means 27 to change the surface temperature of the food 26 ΔT (that is, ΔT). = T (t + Δt) −T (t), where t represents time and Δt represents time change.
The surface temperature T and the variation ΔT of the surface temperature calculated as described above are input to the fuzzy inference means 30. Memory device
Reference numeral 31 stores a control rule necessary for fuzzy inference executed by the fuzzy inference means 30. Fuzzy inference for obtaining the capacity (that is, the number of revolutions) which is the operation amount of the quenching fan 23 is executed based on the following control rule.

The control rules adopted in this embodiment are the following nine rules. For example, rule R1: If the temperature is high and the amount of temperature change is large, strengthen the quench fan very much.Rule R2: If the temperature is low and the amount of temperature change is large, weaken the quench fan. is there. The language rule is a control rule for the control of the quenching fan that is most suitable for the food that is desired to be rapidly cooled, obtained from the empirical rule obtained by the inventor from many experimental data,
This is shown in the table when the relationship between the temperature and the amount of temperature change is shown in the table. The table is a diagram showing the relationship of the control rules for the quenching fan used in the embodiment.

In Table 1, the temperature T is divided into three levels (LT = low temperature, ZO = appropriate temperature, HT = high temperature) in the horizontal direction, and three levels in the vertical direction according to the intensity of the temperature change ΔT (NB = negative, ZO = zero). , PB ＝
The optimum quenching fan capacity for the strength of the temperature T and the temperature change amount ΔT is set in Table 1 at the position where the temperature T and the temperature change amount ΔT intersect with each other. ing. Here, in Table 1, the ability of the quenching fan is divided into five levels (VS = very strong, S = strong,
M = medium, W = weak, VW = very weak). That is, the control rule Ri is shown by a square (Ri) in Table 1. The inventor of the present invention has experimentally confirmed that optimum quenching control can be realized when the capacity of the quenching fan is controlled according to Table 1.

When the language rules are stored in the memory device 31 shown in FIG. 1, they are stored according to the following rule rules. The number of control rules used in the present invention is nine.

Rule R1: IF T is HT and ΔT is PB THEN F = VS Rule R2: IF T is LT and ΔT is PB THEN F = W ・ ・ Next, in the fuzzy inference means 30, the control previously stored in the memory device 31 is performed. The rule is taken out, the capacity, which is the operation amount of the quenching fan 23, is calculated by fuzzy reasoning, and is output to the quenching fan control means 32. The quenching fan control means 32 controls the capacity of the quenching fan 23 according to the determined operation amount.

The rules of the control rules R1, R2, ... R9 determine the capacity of the quenching fan 23 with respect to the temperature T and the temperature change amount ΔT in a stepwise manner. Therefore, when performing fine control, It is necessary to calculate the degree to which the antecedent section (IF section) is satisfied and to estimate the capacity of the quenching fan 23 according to the degree. Therefore, in this embodiment, a membership function of fuzzy variables is used to calculate the degree.

FIG. 3 (a) shows fuzzy variables LT, MT, HT with respect to temperature T.
Membership functions of μLT (T), μMT (T), μHT
FIG. 3B shows the membership functions μPB (ΔT), μZO (ΔT), μNB (ΔT) of the fuzzy variables PB, ZO, and NB with respect to the temperature change amount ΔT. It is a thing.

The fuzzy inference executed by the fuzzy inference means 30 is the control rule 1, rule 2, ... Rule 9 and FIG.
A fuzzy logic operation is performed using the membership function (b) and the operation amount is calculated. As the inference method, the max-min method was used for the synthesis method, and the height method was used for the-pointing method. The inference procedure will be described below with reference to FIG. FIG. 4 is a flow chart showing the inference procedure. In STEP 1, food temperature detection means 2
7. The differentiating means 28 calculates the temperature To and the temperature change amount ΔTo. S
In TEP2, the fuzzy reasoning means 30 calculates the membership value at the temperature To and the temperature change amount ΔTo by using the membership function of the fuzzy variable for the temperature To and the temperature change amount ΔTo. In STEP 3, the degree of the obtained membership value in the antecedent part of each of the nine rules is calculated by a synthesis method. (In FIG. 4, the fuzzy variable with respect to temperature is indicated with A, and the fuzzy variable with respect to temperature variation is indicated with B.) Rule R1: h1 = μHT (To) ∩μPB (ΔTo) = MIN {μHT (To). μPB (ΔTo)}-(1) Rule R2: h2 = μLT (To) ∩μPB (ΔTo) = MIN {μLT (To). μPB (ΔTo)} −− (2) ··· (1) In the equation (1), the To falls within the region HT corresponding to the temperature T, and the ΔTo falls within the region PB corresponding to the temperature variation ΔT.
The proposition of entering is to be satisfied at the ratio of To entering HT and ΔTo entering PB as a smaller value, and therefore the antecedent in the case of rule 1 is satisfied at the ratio of h1. ing. Similarly, in the case of rule 2 which is the expression (2),
It means that the antecedent part holds at the rate of h2. STEP
In Step 4, the operation amount of the quenching fan at the temperature To and the temperature change amount ΔT is calculated by the membership function of the execution unit of the control rule as follows. In order to obtain the manipulated variable Fo of the quenching fan, the constant in the conclusion part is given as the weighted average by h1, h2 ... h9, so Fo = (VS x h1 + W x h2 + ... x h9) / (h1 + h2 + ...・
The operation amount Fo of the quenching fan is collected and output to the quenching fan control means 32 by the height method, which is one of the minus point methods of + h9).

The damper 22 calculates the temperature of the quenching chamber 18 by the signal from the quenching chamber temperature sensor 33 by the quenching chamber temperature detecting means 34, and the damper control means 35 opens and closes the damper 22 according to the output regardless of the above operation. Take control. This damper 22
By this operation, the temperature inside the quenching chamber 18 is always kept constant. At the start of quenching, the temperature inside the quenching chamber also temporarily rises, so the damper 22 is opened.

Next, an example of the rapid cooling operation when this embodiment is applied will be described with reference to FIG. FIG. 5 is a timing chart showing an example of the rapid cooling operation of this embodiment. In Fig. 5 (a)
Shows the changes of the surface temperature of the food 26 with respect to the quenching fan 23, (b), respectively, the solid line shows the case of this embodiment, and the broken line shows the case of the conventional example. In the conventional rapid cooling control, the rapid cooling fan 23 is turned on until the food surface temperature reaches the target temperature (in this case, 5 ° C.) (point A), so the surface temperature continues to drop with the aftereffect even after the rapid cooling is stopped. Overshoot below (point B). Moreover, the temperature gradually recovers after that, and after a while, reaches the target temperature (point C). In the case of the rapid cooling control of this embodiment, the rapid cooling fan is used when the initial surface temperature is high (point D).
By making 23 very strong, the food can be cooled more rapidly than before. After that, by controlling the optimum quenching fan 23 based on the surface temperature of the food and the amount of change in the surface temperature (point E), the target temperature is reached faster than before (point F), and temperature overshoot is suppressed to a minimum. Will be done (g point). In addition, even if the food surface temperature becomes too cold, the cooling fan 23 is controlled as shown in Table 1, so the cold air in the refrigerating room (about 5 ° C) is supplied from the ventilation hole 24.
Therefore, even if supercooling occurs, the target temperature can be reached quickly.

Therefore, in this embodiment, since the surface temperature of the food 26 and the amount of change in the surface temperature are used as the control parameters, fine control can be performed on the food that is desired to be cooled rapidly. In addition, since the control rule is based on human experience, it is possible to control the quenching controller 23 with the optimum capability of the quenching fan 23. Therefore, the food can always be cooled with the optimum cooling capacity, so that the target temperature can be reached quickly, overcooling and undercooling can be prevented, and deterioration of food quality can be prevented. In addition, by providing the ventilation hole 24, even in the unlikely event of overcooling, or even if food with a low temperature is put in, it is possible to circulate the cold air in the refrigerating room, so it is also quick against overcooling. The target temperature can be reached. In addition, because the surface temperature of the food 26 is detected and automatically controlled, there is no need to provide a rapid cooling switch, etc., so the rapid cooling operation is performed automatically, so insufficient rapid cooling due to human error (forgot to switch on, weight setting There will be no mistakes, etc., and it will also lead to cost reduction.

Although the infrared sensor is used to detect the food temperature in the embodiment, the present invention is not limited to this, and information which can be correlated with the surface temperature of the food such as the temperature of the return duct of cold air may be used.

As described above, the quenching control device for a refrigerator according to the present invention is a food temperature detecting means for detecting the temperature of food or the like placed in the quenching room, and a differential for outputting the change amount of the output of the food temperature detecting means. Means, for the information of the output of the food temperature detecting means and the output of the differentiating means, a memory device for storing a control rule based on an empirical rule for obtaining the operation amount of the quenching fan, and the food temperature detecting means. Based on the information of the output and the output of the differentiating means and the control rule extracted from the memory device, fuzzy logic operation is performed to provide a fuzzy inference means for calculating the operation amount of the quenching fan, thereby detecting the food temperature. The operation amount of the quenching fan for the food temperature detected by the means and its change amount is calculated based on the control rule obtained from empirical rules. In the state of, for example, when the rapid cooling begins or just before the end of the rapid cooling, the rapid cooling fan performs the optimal cooling according to the time, so it is possible to always cool the food with the optimal cooling capacity. Can be prevented.

[Brief description of drawings]

FIG. 1 is a block diagram of a refrigerator quenching control apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view of a refrigerator according to an embodiment of the present invention, and FIG. 3 (a) is a fuzzy variable LT with respect to temperature T, M
A characteristic diagram showing the membership functions of T and HT, and FIG. 3 (b) is a fuzzy variable PB, ZO for temperature variation ΔT,
A characteristic diagram showing the membership function of the NB, Fig. 4 is a flow chart showing the inference procedure, Fig. 5 (a) is a timing chart of a quenching fan showing an example of the quenching operation of this embodiment, and Fig. 5 (b). Is a timing chart of the surface temperature of the food. 18 ... Quenching room, 23 ... Quenching fan, 27 ... Food temperature detecting means, 28 ... Differentiating means, 30 ... Fuzzy inference means, 31 ...
… Memory device, 32… Quenching fan control means.

Claims (1)

[Claims] 1. A quenching chamber provided in a part of a refrigerator, a quenching fan for sending air to the quenching chamber, and a food temperature detecting means for detecting the temperature of food or the like placed in the quenching chamber. Differentiating means for outputting the amount of change in the output of the food temperature detecting means, and information on the output of the food temperature detecting means and the output of the differentiating means, based on an empirical rule for obtaining the operation amount of the quenching fan. A memory device for storing a control rule, based on the information of the output of the food temperature detecting means and the output of the differentiating means and the control rule extracted from the memory device, a fuzzy logic operation is performed to perform an operation amount of the quenching fan. A quenching control device for a refrigerator, comprising: a fuzzy inference means for calculating