JPS6144212B2 - - Google Patents

Description

Detailed Description of the Invention: The present invention detects humidity changes due to water vapor emitted from food and automatically heats the food in a way that is suitable for that food.Regarding the food heating method, enter the initial temperature of the food using a key. However, the purpose is to calculate the subsequent heating time from this temperature value and the heating time until the humidity is detected, and to obtain the appropriate heating time to finish the food in an appropriate state.

Conventional humidity-sensing cooking ovens measure the time τ from the time the food starts heating until the food starts boiling.
₀ is measured, and at that point, heating is continued for a time Kτ ₀ , which is the time τ ₀ multiplied by a specific constant K that determines the type and finished state of the food, and the heating is completed. Here, it is thought that the amount of heat Q until the food is finished in an appropriate state may be expressed by the following formula.

Q=m・C・(T _v −T _i )−m・B ...(1) Here, C: Specific heat of food m: Amount of food T _v : Temperature at which water in food boils T _i : Food Initial temperature B: A value specific to food, including the latent heat of evaporation and the amount of heat related to food denaturation.Also, Q is the product of the microwave power P and the total heating time τ of the food, that is, Q = P・T. Therefore, the total heating time of the food is expressed as τ=m・C/P(T _v −T _i )+m/P・B (2). The first term on the right side is the time from the start of heating the food until the water in the food boils;
Since the term can be considered to be the time from the start of boiling until the food is finished in an appropriate state, equation (2) can be expressed as follows.

τ=τ ₀ +Kτ ₀ However, τ ₀ =m・C/P(T _v −T _i )……(3) K=B/C・(T _v −T _i ) In the conventional cooking oven using humidity detection, this
Considering the initial temperature T _i of the food in equation (3) to be approximately 20°C, K is treated as a constant. Therefore, the heating time of the food was controlled using equation (3).

However, some foods that need to be heated include those that have been left in a room at a relatively high room temperature, those that have been taken out of a refrigerator, and those that have been frozen, and there are large differences in the initial temperature immediately before heating. In this way, for foods with initial temperatures over a wide temperature range, K is not a constant but a value that varies widely. Therefore, in conventional cooking ovens, K
As a result of treating this as a constant, some cooking results were not good. This is because the total heating time varies due to the large difference in the initial temperature of the food.

Therefore, either slowly heat the food at low power, or
By repeating heating and resting, the internal temperature of the food approaches the surface temperature, and when it gets close enough, an infrared detector detects when the surface temperature reaches a predetermined set value. The heating time from this point of detection to the point of time when the humidity is detected, when the humidity rises due to the sudden generation of steam, is multiplied by a constant K specific to the food, and the heating is completed further from this point of humidity detection. A heating control method was previously proposed. Here, the predetermined set value of the surface temperature is the initial temperature of the food in this case, i.e.
This is t _i in equations (1), (2), and (3). Therefore,
The value of K in equation (3) must also be newly determined experimentally.

For example, if the new initial temperature, that is, the predetermined set value, is set to 50℃, the food will be heated from 50℃, and from the start of heating, humidity will be detected by the sudden generation of steam coming out of the food. τ ₀ ′ is the heating time from the point of humidity detection until the food is finished in the appropriate state.
_h ′, the new constant K is τ _h ′/τ
₀ ′. Therefore, in the previously proposed method, the set value of the surface temperature must be different depending on the food, and the initial temperature for each must be determined experimentally, making it complicated to handle. There are drawbacks. In addition, in this method, when detecting that the food has reached this predetermined set value, it is detected based on the surface temperature, so the surface temperature may be detected as being far away from the internal temperature due to heating. To prevent this, the internal temperature must be brought close to the surface temperature by heating slowly enough or by repeatedly heating and pausing. This caused the cooking time to take too long.

As another method, the initial temperature of the food is measured, and during the heating time from the start of heating until the surface temperature of the food reaches a predetermined set value, the initial temperature of the food and the set value are measured. There is a heating control method in which heating is continued for a time multiplied by a multiple calculated from a food-specific coefficient determined by the food, the food's specific heat, the food's radio wave absorption rate, etc., until the heating is completed. In this method, even if the surface temperature of the food reaches the predetermined set value, unless the food is heated slowly, the surface temperature of the food will deviate greatly from the internal temperature, and the food will not reach the predetermined set temperature. The value is no longer representative of the temperature, and the overall heating time is not appropriate. Therefore, this method also has the disadvantage that cooking takes too much time because the surface temperature is close to the internal temperature.

In order to eliminate the above-mentioned drawbacks, the cooking oven of the present invention inputs the initial temperature of the food before heating, where the internal temperature and surface temperature are considered to be equal, and stores it in the memory. A humidity detector is used to detect the point at which humidity increases due to the sudden generation of steam.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of a cooking oven for carrying out the food heating method of the present invention. 1 is a heating chamber, 2 is a magnetron, 3 is food, 4 is a food tray, 5 is an operation panel, 6 is a humidity detector, 7 is a flow of water vapor from the food, and the humidity sensor 6 detects the humidity that changes due to this. is detected.

Although a controller for controlling heating is not shown, it is built inside the main body of the cooking oven.

FIG. 2 is an enlarged view of the main parts of the operation panel in FIG. 1, including key switches +, -, 1, 2...
9, a code key, and a numeric keypad.

FIG. 3 is another operation panel showing an enlarged view of the main parts, in which key switches for warm temperature, low temperature, refrigerating temperature, and freezing temperature are provided.

FIG. 4 is an example showing changes in food temperature and relative humidity in the exhaust passage outside the oven as the heating progresses in the cooking oven of the present invention.

The figure shows the temperature change with respect to the heating time when heating frozen food to the final finish (1). Similarly, temperature changes are shown by curve (2).

When food whose initial temperature is T ₁ is heated from time t ₁ , as shown in curve (2), there is little steam coming out of the food at the beginning, so as the temperature inside the oven increases, the relative humidity decreases. I will do it. As the amount of steam increases, the relative humidity reaches its minimum value and then begins to rise, rising at a steep slope. Here, the time t _h when the relative humidity rises from the minimum value by a small threshold value Δh is when a noticeable change in the cooking state of the food occurs, the food begins to boil and the temperature T _v reaches approximately 92° to 97°. It reaches about ℃. Here, the time point t _h at which this relative humidity increases is detected. Then, measure the time τ ₁ from the start of heating this food until reaching this point _v , calculate the coefficient K ₁ using the calculation method described later, and set the subsequent heating time as the product K ₁ τ _1. This is the appropriate heating time.

Similarly, if a food with an initial temperature T ₂ (=0°C) is heated from time t ₂ , heat of fusion is required to convert the water contained in the food into ice, so at a certain point (in the case of the figure)
The temperature does not rise until time point D ₂ ). After this state, the temperature continues to rise, and at time t ₀ the food temperature reaches T ₀ (=20°C).Furthermore, after passing through temperature T ₁ , the time t _h at which the relative humidity increases is detected in the same way as above. do. In this case, from the heating start time t ₂ to this time t
The appropriate heating time is to measure the time τ ₂ until reaching _h , calculate the coefficient K ₂ using the calculation method described later, and set the subsequent heating time to the product K ₂ τ ₂ .

Similarly, if food with an initial temperature T ₃ (<0°C) is heated from time t ₃ , eventually at time t ₂ ,
It reaches the melting temperature (≒0°C) at which the water contained in food changes from ice to water. Since the heat of fusion in this vicinity is required, the temperature does not rise for a certain period of time (in the case of the figure, from time D ₁ to D ₂ ). Thereafter, as described above, the temperature continues to rise, and the time t _h at which the relative humidity rises is detected. In this case, from the heating start time t ₃ to this time t
The appropriate heating time is to measure the time τ ₃ until reaching _h , calculate the coefficient K ₃ using the calculation method described later, and set the subsequent heating time to the product K ₃ τ ₃ .

Next, the reason why an appropriate heating time can be obtained by such a calculation method will be explained with reference to FIG.

Now, if we consider the amount of heat required to finish a food whose initial temperature is 0°C or less in an appropriate state by heating it in a microwave oven, it is thought that it can be expressed by the following formula.

P・τ=m・C ₀・(−T _0i )+m・B ₀ +m・C
(20−T _i )+m・C(T _v −20)+mB ……(4) Where, P: Microwave power τ: Total heating time until the food is finished in an appropriate state m: Amount of food C: Specific heat of food C ₀ : Value corrected by the specific heat of food when it is frozen and the radio wave absorption rate when it is frozen B: A value specific to food that is related to the latent heat of evaporation and denaturation of food B ₀ : Heat of fusion of food , when the temperature of the food is 0℃ or higher, B ₀ = 0 T _v : Temperature when the food starts to boil T _i : Initial temperature of the food, if the temperature of the food is 0℃ or lower, T _i = 0 T _0i : Food The initial temperature when is below 0℃, 0
When the temperature is above ℃, T _0i = 0. However, the evaporation amount of water << m.

In equation (4), the first term on the right side is the sensible heat of the frozen state,
The second term is heat of fusion, the third term is sensible heat up to 20℃, and the fourth term is heat of fusion.
The term represents the sensible heat above 20℃, and the fifth term represents the heat of vaporization and the amount of heat required for food denaturation. Also, from this equation (4), the total heating time of the food becomes as shown in equation (5).

τ=m/P・C ₀・(−T _0i )+m/P・B ₀ +m/P
・C・(20 −T _i )+m/P・C(T _v −20)+mP・B ……(5) Figure 4 shows the temperature change until the frozen food is heated and cooked to the appropriate state. are divided into five stages. Each stage in this figure corresponds to equation (5) above.
In other words, the first term in equation (5) is the time required when the food temperature is below 0°C and corresponds to the area in the figure, and the second term is the time required when the food temperature is 0°C and corresponds to the area. Equivalent to. The third term is the time required from 0 to 20°C and corresponds to the area. Further, the fourth term is the time required from 20°C to _Tv °C and corresponds to the area. Also, the fifth
The term is the time required for the temperature of the food to reach T _v °C until the food is properly cooked, and corresponds to the area.

Here, let τ ₀ =m/P·C·(T _v −20) K ₀ =B/C(T _v −20) (6) and express equation (5) as follows.

First _, in the case _of food whose initial temperature is ₀ ° _{C or higher} , that is, in the area or _{in 0}・τ ₀ /τ ₁ ...(7) K ₀ T _v -20/T _v -T _i Also, in the case of food whose initial temperature is 0℃, that is, the area, τ=τ ₂ +K ₂ τ ₂ However, τ ₂ = m/P・(B ₀ /2+C・T _v )...(8) =K ₀・τ ₀ /τ ₂ In the above formula, B ₀ /2 has a range at 0℃,
Since it is not possible to determine what state the temperature is in, we take the intermediate time point between the state where the temperature starts from minus and the state where the temperature becomes plus, and calculate 1/2 of the heat of fusion.

This ensures that no major errors occur in any case during the melting process.

In addition, in the case of frozen foods whose initial temperature is 0℃ or less, that is, in the area, τ = τ ₃ + K ₃ τ ₃ , where τ ₃ = m/P・(C ₀・T _0i +B ₀ +C・T _v ) K ₃ = K ₀ · τ ₀ / τ ₃ ... (9) = K ₀ C (T _v -20) / C ₀ · T _0i +B
₀ +C・T _vHere , when experimenting with food whose initial temperature is 20℃, the total heating time is from equation (5) τ=τ ₀ +K ₀ τ _0Here , τ ₀ =m/P・C(T _v -20) ...(6)' K ₀ = B/C(T _v -20) τ ₀ can be measured as the heating time until the temperature is detected, and the total heating time τ is the time when the food is Since it can be measured as the time required to finish the product in an appropriate state, K ₀ can be determined from equation (6)' as K ₀ = (τ - τ ₀ )/τ ₀ , which is a constant that can be determined experimentally for each food. You can think about it.

The first terms of equations (7), (8), and (9), that is, the heating times τ ₁ , τ ₂ , and τ ₃ from the initial temperature to the temperature T _v when boiling starts, are all Electric power P
and the part that is inversely proportional to the amount of food m, and C, T
_v , T _i , B ₀ , C ₀ , and T _0i . Due to this latter part, the heating time τ ₁ , τ ₂ ,
_τ3 increases or decreases, but at the end of these heating times, the temperature at which the food begins to boil is T.
reach _v .

However, for any food at any initial temperature, it is possible to measure the times τ ₁ , τ ₂ , and τ ₃ from when heating begins until the food reaches the temperature at which it starts boiling. On the other hand, T _v , C, B ₀ , which are determined by the measurement of the initial temperature T _i or T _0i and the food
The value of C ₀ and the constant determined experimentally in advance
The coefficients K ₁ , K ₂ , and K ₃ that vary depending on K ₀ have been calculated. Therefore, the heating time of the food after it reaches the temperature at which it starts boiling K ₁ τ
₁ , K ₂ τ ₂ and K ₃ τ ₃ are calculated from the changing coefficients K ₁ , K ₂ , K ₃ and the time from the start of heating to the final measured temperature τ ₁ , τ ₂ , τ _3, respectively. It can be calculated. Therefore, in this way, the total heating time can be determined without measuring the amount m of the food. In addition, in this case, it is not necessary to provide the actual value of the food-specific value B related to the latent heat of evaporation and food denaturation, but rather a food-specific coefficient that can be obtained in advance through experimental measurements for each food. K ₀ can be substituted. Here, the temperature _Tv at which the food begins to boil is selected to be around 95°C. Furthermore, since most foods have a high water content, the specific heat C of most foods can be considered to be 1.0, which is the same as when comparing water.

Furthermore, the heat of fusion B ₀ of food can be considered to be the heat of fusion of water, 79.7ca/g, considering that food has a high water content. Furthermore, assuming that the water content is ice, the specific heat of food in a frozen state is 1.16 at 0°C, 1.11 at -20°C, and 0.84 at -80°C, which is not much different from the specific heat of water. However, the radio wave absorption rate of frozen foods differs depending on the temperature, but beef has a radio wave absorption rate of 0.13 compared to non-frozen foods.
~0.17 times, 0.11 for peas, 0.14 for ground pork,
0.08 with potatoes, 0.24 with spinach, 0.08 with potatoes, 0.24 with pumpkin.
It is 0.04.

This radio wave absorption rate slows down in inverse proportion to the temperature rise due to food heating, so it takes a long time for frozen food to rise in temperature. As for C ₀ , the above foods range from 4.6 to 29.0.

FIG. 5 is another example showing the temperature of the food and the relative humidity in the exhaust passage outside the oven which change as the food is heated in the cooking oven of the present invention.

The 1a curves in the figure show temperature changes and relative humidity changes, respectively. Start heating food whose initial temperature is T ₀ = 20°C at time t ₀ , heat it for a time τ ₀ until the humidity is detected, and then continue to heat it for a time equal to this time multiplied by a coefficient K ₀ to complete the heating. It shows.

In addition, the same food with an initial temperature T ₁ is heated from time t ₁ , heated for τ ₁ until the humidity is detected, and then the coefficient K ₁ is calculated from _the initial temperature, etc. τ This indicates that the product can be heated to an appropriate state after further heating for ₁ hour.

Curves 1b and 2b similarly show temperature changes and relative humidity changes, but they are the same type of food as 1a and 1b, but the amount is large, and the initial temperature T ₀ = 20°C
Heating starts at time t ₀ ', is heated for a time τ ₀ ' until the humidity is detected, and is then further heated for a time K ₀ τ ₀ ', which is this time multiplied by a coefficient K ₀ . In other words, it is shown that an appropriate state can be achieved in a total heating time of τ ₀ ′+K ₀ τ ₀ ′. Naturally, τ ₀
+τ The time is longer in proportion to the amount of food than ₀ .

FIGS. 6 and 7 each show examples of keys on the operation panel for setting the initial temperature of food.

In FIG. 6, reference numeral 11 denotes a key portion of the operation panel, which has 12 key switches of +, -, 0, 1.2, 3, . . . , 8, and 9. 12 is an encoder which outputs 4-bit outputs DI ₁ , DI ₂ , DI ₃ , and DI ₄ that encode the keys of the operation panel 11 .

In addition, in FIG. 7, 13 is an example of an operation panel different from 11 in FIG.
It has four key switches: ``refrigerated temperature'' and ``frozen temperature.'' 14 is a buffer which receives the on/off status of each key switch "warm temperature", "low temperature", "refrigeration temperature", and "freezing temperature" on the operation panel 13, and converts it to a level suitable for input to the microphone computer. The outputs are DI ₁ ′, DI ₂ ′, and DI ₃ ′, respectively.

In FIG. 8, 6 is a humidity detector, 15 is an amplifier that amplifies the humidity signal, and 16 is a minimum value holding circuit that updates and holds the smaller value of the minimum value of the output voltage of the amplifier 15. A subtracter 17 subtracts the instantaneous value of the output voltage of the amplifier 15 from the minimum value held in the minimum value holding circuit. This subtracted output is compared with a threshold value Δh by a comparator 18. As a result of the comparison, if the output from the subtracter is greater than the threshold, the comparator detects the relative humidity due to water vapor released from the food and outputs a humidity detection signal (HUM). In addition, the minimum value holding circuit 24
There is a hold/erase signal (HOCD/RESET) as an input to hold the hold voltage or erase and return to the start.

In FIG. 9, 19 is a heating control circuit that controls the magnetron drive/stop for driving and stopping the magnetron 20.
It is controlled by inputting a stop signal (STA/ STO ).

FIG. 10 shows a control unit according to the present invention, which uses an LSI chip. In this example, the microcomputer 20 is a general-purpose chip using a stored program method.
0 is used.

A ₀ , A ₁ , A ₂ , A ₃ , B ₀ , B ₁ , B ₂ , B ₃ and S ₀ are input terminals, and C ₀ to C ₉ are output terminals. input terminal
A heating start signal (START) and a humidity detection signal (HUM) are input to A ₀ and A ₁ , respectively. In addition, 4-bit signals DI _{1 , DI 2 , DI 3 , which represent the set initial temperature are input to the input terminals B 0 , B 1 B 2} , and B ₃ .
DI ₄ or signals DI ₁ ′, DI ₂ ′, DI ₃ ′, and DI ₄ corresponding to the set initial temperature are input.

Further, a clock pulse (CLOCK) (for example, a commercial frequency) serving as a time reference is input to the input terminal _S0 .

A magnetron drive/stop signal (STA/ STO ) and a holding voltage holding and erasing signal (HOLD/RESET) of the minimum value holding circuit 24 are output to the output terminals C ₅ and C ₉ , respectively.

FIG. 11 is a block diagram showing the configuration of the microcomputer 200. The functions and data processing process of the microcomputer 200 will be outlined using FIG.

The first function is a logic operation function, which includes a logic operation unit (ALU) 201, an accumulator (ACC) 202, a temporary register (TEMP) 203, a program status flag (PS) 204, a carry flag 205, and a zero flag. 206, Seeds Complement (T/
C) 207 and 4-bit A and B paths for data transfer. ALU2
01 is a logic operation unit that can perform logical product, logical sum, exclusive logical sum, and addition. T/
C207 calculates the two's complement of the data transferred to ALU201, so
ALU 201 can perform subtraction.

PS204, CF205, and ZF206 are 1-bit flip-flops for storing the system state. PS204 is a flag that is set and reset by instructions, and CF2
05 and ZF 206 are set and reset based on the calculation result of ALU 201 depending on the presence or absence of a carrier, and the ZF 206 is set and reset depending on whether the calculation result of CF 205 is zero or not, and is used for various determinations in program execution.

ACC202 and TEMP203 are 4-bit registers for temporarily storing ALU input data, calculation results, etc.

The second function is a data storage function. This function is variable memory RAM209, X register 2
34, is executed by the Y register 235.

The address of the RAM 209 is specified by the X and Y registers 234 and 235, and
The contents of the RAM 209 can be transferred to the ACC 202 and the like.

The third function is a program storage and execution function that stores and executes programs.

This function includes a fixed memory ROM210, a program counter PC208, a subroutine stack STACK211, and a stack pointer SP212.
Executed by The ROM 210 stores a program written in 8-bit instruction words to be executed by the system, and the PC 208, which is constituted by a binary counter, specifies the address of the ROM 210. Therefore, as the PC 208 counts up, the program stored in the ROM 210 is executed word by word.
The STACK 211 stores the contents of the PC 208 in order to specify the address to return from the subroutine when executing the subroutine of the program. SP is used to specify the first address to return to when executing a subroutine at two levels.

The fourth function is an instruction decoding function.

This function is available in instruction register IR2.
13. Instructions are executed by programmable logic array I-PL214.

IR 213 is an 8-bit register for latching the 8-bit instruction word transferred from ROM 210 while the instruction is executed. I-PLA2
14 performs the function of converting the 8-bit instruction word transferred from the ROM 210 into a control signal. Therefore, the 8-bit instruction word stored in the ROM 210 by the I-PLA 214 sequentially becomes various control signals and is used as a control signal. Each functional unit (e.g. ALU, ACC,
RAM... etc.), and μ-P is sent to ROM210.
It operates based on the program stored in the.

The fifth function is a counter function. counter 2
15 is an 8-bit binary counter, which is set and reset by a counter flip-flop E/DFF 216. E/DFF216
When the counter 215 is enabled to count, it counts up the pulse input from the _S1 input terminal, and when it counts up to the most significant bit (MSB), the set flag SF217 is set. Therefore, the E/DFF 216 is set and reset by instructions from the ROM 210, and the SF
By checking whether 217 is set, the number of pulses from the _S1 input can be counted. Furthermore, the contents of the counter 215 can be divided into the upper 4 bits and the lower 4 bits and transferred directly to the ACC 202 or the like.

The sixth is an input/output function.

The input terminals include 4-bit parallel input terminals _A0 to _A3 and 4-bit parallel input terminals _B0 to _B3 .

These two sets of parallel inputs A ₀ to A ₃ and B ₀ to _{B 3} can be selectively transferred to the ACC 202 or the like via the B path 219 by the multiplexer MPX 218 .

The A ₀ to _{A 3} and B ₀ to _{B 3} inputs are used for inputting data.

Other input terminals include Sφ and _S1 input terminals. This input terminal is convenient for counting pulse signals and performing interrupt operations independently of the μ-P clock.

A comparator C220 determines whether the Sφ input is high or low.

The _S1 input is connected to the counter 21 by gate G221.
This terminal can be input to SF217 via synchronization circuit S222, and compared by comparator C223, and can be used in the same way as the Sφ input. S ₁ input counter 215
It can be selected by inputting the CS pin.

The RST input pin is connected to the μ
-P can be used for purposes such as stopping the program stored in the ROM 210 at the start (address 0) until power is established to prevent malfunctions. At this time, all output terminals become L ₀ . The OSC input terminal is a terminal to which a capacitor and a resistor are connected in order to determine the oscillation frequency of the built-in oscillator 224. A logic control circuit 236 controls the internal operation of μ-P using the oscillation frequency of this oscillator as a clock.

Further, V _SS and V _DD are power supply terminals.

Next, there are three types of output terminals.

The first output terminal is a D output terminal consisting of _D0 to _D7 . The data in RAM 209 or ACC 202 and PS 204 are latched by latch 225 to create programmable logic array PLA 226.
When the data is transferred as 5-bit data, the data (5 bits) is output as parallel 8-bit output to eight output terminals _D0 to _D7 . Therefore,
These output terminals D ₀ to D ₇ are suitable for display on a 7-segment display tube.

The second output terminal is an E output terminal consisting of E ₀ to E ₃ and can output 4-bit data in parallel from the ACC 202 or ROM 210. 22
7 is a latch.

The third output is a C output terminal consisting of C ₀ -C ₁₁ , each of which can be independently set or reset. That is, Y register 23
5 specifies which C output to set,
The C output terminal corresponding to the decoder 228, which issues the output command, is latched by the latch 229 and output. Therefore, various loads can be controlled with this C output terminal.

Note that 230, 231, and 232 are multiplexers, and 233 is a comparator.

The functions and data processing process of the μ-P shown in FIG. 8 have been outlined above, and the present invention shows an embodiment using such a μ-P.

Figures 12 and 13 are flowcharts of a heating control program using a microcomputer for food heating control according to the method of the present invention. The flowchart, Figure 13, is as follows:
This is a flowchart from the start to the completion of heating food.

Hereinafter, aspects of the control operation according to the method of the present invention will be explained with reference to FIGS. 1 to 13.

First, food is placed in the oven shown in FIG. If the initial temperature of the food is known, use the keys on the operation panel shown in FIG. 2 to set that temperature, or if unconfirmed, use the keys on the operation panel shown in FIG. The setting method is to first set the food temperature
Key in one of the numbers, then the 10th digit number, and finally the 1st digit number.
For example, if you want to set +15℃, first
Next, key in 1 and finally 5. In this case, the encoder 12 shown in FIG. 6 first generates 4-bit signals DI ₁ , DI ₂ , DI ₃ , and DI ₄ corresponding to +, which are input to the input terminal of the microcomputer.
Input to B ₀ , B ₁ , B ₂ , and B ₃ . Next, a 4-bit signal corresponding to 1 is inputted in the same manner, and finally a 4-bit signal corresponding to 5 is inputted.
In the microcomputer, as shown in the program of FIG. 12a, in program operation 1, the
Deciphers the bit signal and converts it into the original code or number. Furthermore, in program operation 2, one code and two numbers are taken in and stored as the initial temperature data of the food. For example, in the above example, +15 is stored.

Alternatively, in the example method of easily setting the initial temperature of food to a rough value, press the keys "Warm Temperature", "Low Temperature", "Refrigerating Temperature", and "Freezing Temperature" on the operation panel shown in Figure 3.
Key in one of the following. In this case, the on/off states of the keys ``warm temperature'', ``low temperature'', ``refrigeration temperature'', and ``freezing temperature'' shown in _{FIG .} , DI ₃ ′,
DI ₄ ' is output, which is input to the input terminals B ₀ , B ₁ , B ₂ , and B ₃ of the microcomputer. As shown in FIG. 12b, the microcomputer outputs signals DI ₁ ′, DI ₂ ′, DI ₃ ′, which correspond to whether the key is warm, cold, refrigerated, or frozen, respectively.
It is determined by DI ₄ ' and is converted into a constant corresponding to each input in program operations 3, 4, 5, and 6, respectively. For example, consider warm temperature as a temperature of 20℃ or higher, and consider it as a temperature of 25℃ for an input of DI ₁ ′, and consider a low temperature as a temperature of 10 to 20℃, and input a value of 15℃ for an input of DI ₂ ′. In addition, considering the refrigeration temperature to be a temperature between 0 and 10℃, and considering the input of DI ₃ ' to be 5℃, and considering the freezing temperature to be -30 to -5℃, and the input of DI ₄ ', , −15
Convert to °C. Furthermore, in program operation 7, the converted temperature is used as the initial temperature data of the food.
Store.

When heating is started after the initial temperature of the food has been set in this way, a heating start signal (START) is input to the input terminal _A0 of the microcomputer shown in FIG. As a result, when the heating of the food progresses and the relative humidity exceeds the threshold value Δh from its minimum value, a humidity detection signal (HUM) is output from the comparator 26 shown in FIG. This signal is the input terminal of the microcomputer shown in Figure 7.
Input from A ₁ and stored as data.

On the other hand, as shown in the flowchart of FIG. 13, the program is executed by the program storage and execution functions of the microcomputer.

The control operation begins upon input of the heating start signal, and first, as an initial setting, a variable coefficient K is set to zero, and constants C ₀ , B ₀ , K ₀ , and T _v are set.

Next, the initial temperature T _i (including T _i ) of the food that has been set and stored in the RAM as described above is loaded and compared with “OC”, and when it is equal to or higher than “OC” (as shown in Figure 4) area) is K=K ₀ (T
_v −20)/(T _v −T _i ), when equal to “OC” (in the region shown in Figure 4), K=K ₀
Calculation of (T _v −20)/(B ₀ /2+T _v ), and
When below “OC” (when in the area shown in Figure 2)
is calculated as K=K ₀ (T _v −20)/(−C ₀ T _i +B ₀ +T _v ).

Furthermore, as explained above, from the start of heating until the humidity detection signal is stored at time t _h shown in FIG. 4 and it is determined whether humidity has been detected, the RAM, which is a variable memory, , whose contents are τ
=0 and increases with the number of clock pulses. Then, when it is determined whether humidity has been detected,
The RAM content τ is multiplied by K. As a result, the time Kτ from time t _h to t _e shown in FIG. 4 is obtained. After that, decrease this time value Kτ,
Until the content of the RAM becomes "O", that is, at time _te , when the content is determined to be "O", a start/stop signal (STA/ STO ) is output from the output terminal _C5 of the microcomputer. be done.
This signal is input to the heating control circuit 19 in FIG. 6, and the magnetron 20 is stopped to complete the cooking.

Note that the above-mentioned times τ and Kτ are input from the _S0 input terminal of the microcomputer using a clock pulse (CLOCK) (for example, a commercial frequency) that serves as a time reference.
This can be achieved by inputting and counting in the RAM area.

As is clear from the above description, the following effects can be obtained according to the present invention.

(1) Compared to the conventional method of determining the subsequent heating time based on the heating time from the start of heating to the point at which humidity is detected, the initial temperature of the food is entered by key and stored in memory before heating starts. However, since the subsequent heating time is calculated from this value and the two values from the start of heating until the humidity is detected, there is no error in determining the heating time due to variations in the initial temperature of the food, and even in the case of frozen food. Including this, the heating time for properly finishing the food can be obtained almost unaffected by the initial temperature of the food.

(2) The time required to slowly heat the food until the surface temperature of the food reaches the temperature setting value determined by the food, and then multiply the time it takes to detect the temperature by a food-specific constant; Compared to the method of further heating from the time of temperature detection, or
After measuring the initial temperature of the food and starting heating,
Compared to the method of the present invention, which calculates the coefficient K based on the time taken for the surface temperature of the food to reach a predetermined set value, the method of the present invention calculates the coefficient K based on the time taken for the surface temperature of the food to reach a predetermined set value. Since it is not necessary to detect the temperature close to the internal temperature, heating can proceed faster and the total heating time for properly finishing the food can be shortened.

(3) When cooking food, you can calculate the amount of food, the amount of food, etc. by simply specifying the type of food. Automatic cooking with little effect on heating output can be achieved by automatically measuring the initial temperature of the food and the time from the start of heating to the detection of humidity.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a cooking oven that implements the food heating method of the present invention, Fig. 2 is an enlarged view of the main part of the operation panel in Fig. 1, and Fig. 3 is a main part of another operation panel in Fig. 1. Figure 4 is a temperature curve diagram and relative humidity curve diagram that change as food is heated by the method of the present invention, Figure 5 is a temperature curve diagram due to differences in the amount of food according to the method of the present invention, and Figure 6 The figure is an example configuration diagram of keys on an operation panel for setting the initial temperature of food according to the method of the present invention, and FIG. 7 is an example configuration diagram of keys on an operation panel for setting the initial temperature of food according to another method of the present invention. , FIG. 8 is a block diagram for humidity detection in a cooking oven according to the method of the present invention, FIG. 9 is a block diagram for heating control in a cooking oven according to the method of the present invention, and FIG. FIG. 11 is a configuration diagram of a microcomputer that is part of the control unit, and FIGS. 12a, b, and 13 are schematic flowcharts of a heating control program by the microcomputer for food heating control according to the present invention. It's a chat. 3... Food, 6... Humidity detector.

Claims (1)

[Claims] 1. A cooking device comprising a humidity detection section that detects humidity that changes with water vapor emitted from food, a food-specific coefficient setting section determined depending on the type of food, and a food initial temperature setting section. When the initial temperature setting is higher than 0°C, τ ₁ is the time it takes for the humidity to rise rapidly due to the rapid generation of water vapor from the food in a food oven. The case is τ ₂ , the case below 0°C is τ ₃ , P is the microwave power, m is the amount of food, C is the specific heat of the food, C ₀ is the specific heat when the food is frozen and the radio wave absorption rate when it is frozen. is the corrected value, B is the food-specific value related to the latent heat of vaporization and food denaturation, B ₀ is the heat of fusion of the food, T _V is the temperature at which the food begins to boil, and T _i is the initial temperature of the food. Temperature, T _0i is the initial temperature of the food when it is below 0°C, and if the amount of water evaporation << m, the total heating time of the food is τ, and when the initial temperature of the food is higher than 0°C, τ = τ ₁ +B/C(TV _{-T i} )・τ ₁ , if the initial temperature of the food is 0℃, use [formula], and if the initial temperature of the food is less than 0℃, τ = τ ₃ +
A food heating control method, characterized in that B/C ₀ ·T _0i +B ₀ +C · T _V · τ ₃ , and heating the food for a total heating time τ based on this formula. 2. Detects and maintains the minimum humidity value that changes due to water vapor emitted from food, and detects when the humidity increases by a predetermined threshold above that value. A food heating control method according to claim 1, characterized in that: