Method for Load Detection in a Cooking Chamber of a Cooking Device and Cooking Device

Abstract

A method for load detection in a cooking chamber of a cooking device is described. At least one cooking chamber climate value in the cooking chamber is acquired. A gradient of a temperature change is acquired using a temperature sensor associated with a microwave trap or a microwave absorber. The at least one cooking chamber climate value and the gradient of the temperature change are evaluated jointly to estimate the load in the cooking chamber of the cooking device. Furthermore, a cooking device for cooking food to be cooked is described.

Claims

1. A method for load detection in a cooking chamber of a cooking device, the method comprising the following steps: acquiring at least one cooking chamber climate value in the cooking chamber; acquiring a gradient of a temperature change using a temperature sensor associated with a microwave trap or a microwave absorber; and jointly evaluating the at least one cooking chamber climate value and the gradient of the temperature change to estimate the load in the cooking chamber of the cooking device.

2. The method according to claim 1, wherein the joint evaluation takes place in a time period in which the information of the temperature sensor associated with the microwave trap or the microwave absorber and the information of the cooking chamber climate value are decorrelated.

3. The method according to claim 1, wherein the cooking chamber climate value is an actual value of the cooking chamber climate in the cooking chamber.

4. The method according to claim 1, wherein the cooking chamber climate value is a historical cooking chamber climate value of the cooking chamber climate in the cooking chamber.

5. The method according to claim 1, wherein the at least one cooking chamber climate value is used to determine a load controller value.

6. The method according to claim 5, wherein an actual cooking chamber climate value and a historical cooking chamber climate value are used to determine the load controller value.

7. The method according to claim 1, wherein the at least one cooking chamber climate value and the gradient of the temperature change are plotted against each other to obtain a two-dimensional point which is evaluated in the joint evaluation to estimate the load in the cooking chamber of the cooking device.

8. The method according to claim 1, wherein the at least one cooking chamber climate value and the gradient of the temperature change are evaluated in a weighted manner during the joint evaluation.

9. The method according to claim 8, wherein weighting factors specific to the type of food to be cooked are provided.

10. The method according to claim 1, wherein an artificial intelligence is provided which performs the joint evaluation.

11. The method according to claim 10, wherein the artificial intelligence has been trained in advance to select weighting factors for the gradient of the temperature change and the at least one cooking chamber climate value.

12. The method according to claim 1, wherein at least one future value for the cooking chamber climate and/or the gradient of the temperature change is predicted during the joint evaluation of the at least one cooking chamber climate value and the gradient of the temperature change.

13. The method according to claim 1, wherein the microwave trap or the microwave absorber and the temperature sensor associated with the microwave trap or the microwave absorber are both integrated in a core temperature probe.

14. A cooking device for cooking food to be cooked, wherein the cooking device comprises a cooking chamber, a microwave source associated with the cooking chamber, at least one climate sensor for acquiring a cooking chamber climate value in the cooking chamber, and at least one temperature sensor associated with a microwave trap or a microwave absorber, wherein the cooking device further comprises an evaluation unit which is connected to the at least one climate sensor and the at least one temperature sensor associated with the microwave trap or the microwave absorber in a signal-transmitting manner, and wherein the evaluation unit is arranged to jointly evaluate a cooking chamber climate value acquired by the climate sensor and a temperature value acquired by the temperature sensor associated with the microwave trap or the microwave absorber by determining the gradient of a temperature change, which is evaluated jointly with the cooking chamber climate value, to estimate a load in the cooking chamber of the cooking device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Further advantages and features of the claimed subject matter will become apparent from the description below and the drawings, to which reference is made and in which:

[0053] FIG. 1 shows a schematic representation of a cooking device according to an embodiment of the present disclosure,

[0054] FIG. 2 shows a schematic representation of a load sensor assembly,

[0055] FIG. 3a and FIG. 3b show diagrams for different loading scenarios, wherein in the diagrams, the temperature detected by the temperature sensor associated with the microwave trap or the microwave absorber and the voltage supply of a microwave source are plotted against time, and

[0056] FIG. 4 shows a representation of a two-dimensional feature space for estimating the load present in the cooking chamber.

DETAILED DESCRIPTION

[0057] FIG. 1 shows a cooking device 10 for cooking food to be cooked 12 that has been placed on a rack 13 in a cooking chamber 14 of the cooking device 10 to be cooked there. The rack has a plurality of levels, wherein at least one food item to be cooked 12 may be provided on each of the plurality of levels. In particular, the cooking device 10 or the cooking chamber 14 may be loaded differently, that is, loaded with different amounts of food to be cooked 12, for example distributed among the different levels of the rack 13.

[0058] The cooking chamber 14 is separated from an installation chamber 15, which, among other things, at least partially accommodates the components that serve to set a cooking atmosphere in the cooking chamber 14 or provide the energy for cooking the food to be cooked 12.

[0059] In the embodiment shown, the cooking device 10 includes a heating device 16, a steam device 18, and a microwave source 20 associated with the cooking chamber 14, by means of which microwaves can be generated and fed into the cooking chamber 14 to (additionally) apply energy to the food to be cooked 12. For this purpose, at least one antenna 21 may be assigned to the microwave source 20, which faces the cooking chamber 14 to feed the electromagnetic waves (microwaves) provided by the microwave source 20, for example a semiconductor component or a magnetron, into the cooking chamber 14.

[0060] The heating device 16 and/or the steam device 18 can be used to generate the cooking atmosphere in the cooking chamber 14, which is also referred to as cooking chamber climate, i.e. a defined temperature and/or a defined humidity to which the food to be cooked 12 is exposed during cooking.

[0061] Alternatively or additionally, an infrared source which serves as a heating device 16 may also be provided.

[0062] In addition, the cooking device 10 comprises at least one climate sensor 22, which may be configured, for example, as a humidity sensor and/or temperature sensor, the climate sensor 22 detecting a cooking chamber climate value in the cooking chamber 14, i.e. the temperature in the cooking chamber 14 and/or the humidity in the cooking chamber 14.

[0063] Furthermore, the cooking device 10 comprises a microwave trap 24 in which the microwaves that have been emitted by the microwave source 20 and reflected can be at least partially absorbed, as a result of which the microwave trap 24 heats up.

[0064] Alternatively or in addition to the microwave trap 24, a microwave absorber may also be provided which absorbs microwaves fed into the cooking chamber 14 by the microwave source 20, as a result of which the microwave absorber heats up.

[0065] A temperature sensor 26 which detects the corresponding temperature change of the microwave trap 24 or the microwave absorber, respectively, is associated with the microwave trap 24 or the microwave absorber allowing an estimation of the load introduced into the cooking chamber 14, i.e., the amount of food to be cooked 12.

[0066] The microwave trap 24 and the associated temperature sensor 26 are for example integrated into a core temperature probe 27. Similarly, the microwave absorber and the associated temperature sensor may be integrated into the core temperature probe 27.

[0067] In either case, the microwave trap 24 and the associated temperature sensor 26 or the microwave absorber and the associated temperature sensor 26 together constitute a load sensor assembly 28.

[0068] Alternatively to the core temperature probe 27, the load sensor assembly 28 can also be formed separately and placed in the cooking chamber 14, for example arranged on a cooking chamber wall 29 of the cooking chamber 14.

[0069] FIG. 1 shows both options of the load sensor assembly 28 accordingly.

[0070] In particular, it may also be provided that a microwave trap 24 with an associated temperature sensor 26 and a microwave absorber with an associated temperature sensor 26, i.e. two different load sensor assemblies 28 are provided.

[0071] In the following, the preferred example embodiment will be discussed in more detail, in which a microwave trap 24 is provided, as it has a higher accuracy and thus a higher resolution than a microwave absorber.

[0072] The separately formed load sensor assembly 28 is also shown in detail in FIG. 2. The latter shows that the load sensor assembly 28 also has, in addition to a dielectric 30, a separately formed antenna 32 to (better) receive the electromagnetic waves from the cooking chamber 14, i.e. the microwaves emitted by the microwave source 20.

[0073] In the embodiment shown, the temperature sensor 26 is provided on an opposite side of the corresponding cooking chamber wall 29, for example within the installation space 15. It is thus ensured that the electromagnetic waves cannot reach the temperature sensor 26, as the latter is electromagnetically shielded by the cooking chamber wall 29. Alternatively, the temperature sensor 26 can also be arranged on the same side of the cooking chamber wall 29 as the microwave trap 24, as indicated in FIG. 1. In that case, it must be ensured by other means that the electromagnetic waves do not influence the temperature sensor 26.

[0074] In an alternative configuration, the separately formed load sensor assembly 28 can also be formed without an antenna 32, the dielectric 30 arranged within the microwave trap 24 also functioning as an antenna.

[0075] Basically, the microwave trap 24 has an open side via which the microwaves can enter the microwave trap 24. In addition, the microwave trap 24 has a side opposite to the open side, which is also referred to as the bottom of the microwave trap 24.

[0076] The dielectric 30 which has been inserted into the microwave trap 24, for example, via the open side is provided within the microwave trap 24.

[0077] The dielectric 30 shortens the geometric length of the microwave trap 24 while maintaining the electrical length of the microwave trap 24. Focusing effects improve the effectiveness of the microwave trap 24.

[0078] The dielectric 30 may be formed of a ceramic, for example an oxide ceramic such as alumina (Al.sub.2O.sub.3), or polytetrafluoroethylene (PTFE).

[0079] Provided that the field strength or the energy density in the microwave trap 24 is already very high, the dielectric 30 may be formed by the antenna 32 or another component.

[0080] Silicon carbide (SSiC) may also be provided to increase the microwave losses in the microwave trap 24 if the field strength or losses of Al.sub.2O.sub.3 or PTFE are not sufficient to achieve a sufficient temperature swing. SSiC absorbs the microwaves much more strongly compared to Al.sub.2O.sub.3 and PTFE.

[0081] If the load sensor assembly 28 is implemented by the core temperature probe 27, the latter may include a piercing section for piercing the food to be cooked 12, and a grip section through which the core temperature probe 27 may be or is intended to be grasped by a user.

[0082] The piercing section is formed of, for example, a thermally conductive material (material having a high thermal conductivity), in particular a metal, whereas the grip section may be made of a plastic or a material having a low thermal conductivity, for example a heat-resistant plastic such as a polyetheretherketone (PEEK).

[0083] A core temperature sensor is associated with the piercing section, via which the core temperature of the food to be cooked 12 can be measured when the core temperature probe 27 has been inserted into the food to be cooked 12 via the piercing section thereof.

[0084] The load sensor assembly 28, i.e. the microwave trap 24 and the associated temperature sensor 26, is furthermore provided in the core temperature probe 27. For example, the microwave trap 24 and the temperature sensor 26 are both arranged in the grip section of the core temperature probe 27 so that they are accommodated in a protected manner.

[0085] Thus, as shown in FIG. 1, the load sensor assembly 28 may be integrated into the core temperature probe 27 or formed separately from the core temperature probe 27.

[0086] In any case, regardless of its specific configuration, the load sensor assembly 28 includes, in addition to the temperature sensor 26, the microwave trap 24 in which the dielectric 30 is arranged.

[0087] The microwave trap 24 is formed of an electrically conductive material, such as a metal. In this respect, the microwave trap 24 may also be formed of a material having a high thermal conductivity.

[0088] Generally, the microwave trap 24 of the load sensor assembly 28 ensures that electromagnetic waves coupled in oscillate in resonance with the structure, thereby forming field rises.

[0089] In principle, the load sensor assembly 28 ensures that a dielectric load in the cooking chamber 14, for example the food to be cooked 12 or a cooking accessory, can be determined easily and quickly. However, an empty cooking chamber 14 can also be clearly detected. For this purpose, the temperature of the microwave trap 24 is detected by means of the associated temperature sensor 26.

[0090] This is possible because a corresponding electric field is formed as a function of the dielectric load present in the cooking chamber 14.

[0091] The electric field present in the cooking chamber 14 ensures that an electric field is also formed in the load sensor assembly 28, in particular the microwave trap 24, which is proportional to the electric field in the cooking chamber 14. Consequently, the electric field of the load sensor assembly 28 depends on the dielectric load present in the cooking chamber 14.

[0092] As a function of the electric field in the load sensor assembly 28, particularly in the microwave trap 24, ohmic losses and dielectric losses proportional thereto occur in the microwave trap 24, which in turn generate heat loss. This heat loss results in a temperature change of the microwave trap 24, which is detected by the temperature sensor 26. Therefore, the temperature of the microwave trap 24 detected by the temperature sensor 26 can be used to indirectly infer the dielectric load present in the cooking chamber 14.

[0093] Furthermore, the cooking device 10 includes an evaluation unit 34 which is connected in a signal-transmitting manner to the climate sensor 22 and at least to the temperature sensor 26 which is associated with the microwave trap 24, in particular to the load sensor assembly 28.

[0094] The evaluation unit 34 thus receives the information from the climate sensor 22, i.e. the detected cooking chamber climate value, and the information from the temperature sensor 26, i.e. the detected temperature of the microwave trap 24, which allows conclusions to be drawn about the electric field in the cooking chamber 14 and thus the (dielectric) load in the cooking chamber 14.

[0095] The evaluation unit 34 is arranged to detect, among other things, a temperature change of the microwave trap 24 on the basis of the acquired information, in particular to determine the gradient of the temperature change.

[0096] Furthermore, the evaluation unit 34 can evaluate the determined gradient of the temperature change together with the cooking chamber climate value to estimate the load in the cooking chamber 14 of the cooking device 10 therefrom. A sensor data fusion thus takes place, as the sensor data of two different sensors are evaluated together, namely that of the climate sensor 22 and that of the temperature sensor 26 associated with the microwave trap 24.

[0097] The sensor data fusion is necessary to avoid incorrect estimations with regard to the introduced load, i.e. the charging, which can occur if only the temperature in the cooking chamber 14 is taken into account, as shown in FIGS. 3a and 3b.

[0098] In fact, the cooking chamber 14 there has been loaded with three trays (FIG. 3a— #Trays=3) and with one tray (FIG. 3b— #Trays=1), thus three levels of the rack 13 and one level of the rack 13, respectively, have been used.

[0099] A comparison of the two figures shows that the temperature of the temperature sensor 26 associated with the microwave trap 24 cools down before the microwaves are applied, i.e., before the microwave source 20 is switched on, causing the slope of the temperature to be negative. However, this has the effect that in particular the load is overestimated when only one tray is loaded.

[0100] Therefore, it is provided that in addition to the temperature sensor 26 associated with the microwave trap 24, the information of the climate sensor 22 is also taken into account, i.e., the cooking chamber climate of the past (“historical cooking chamber climate values”), of the present (“actual values”) and/or the future target climate (“set values”), to make an appropriate load prediction.

[0101] In other words, a joint evaluation of the at least one cooking chamber climate value and of the gradient of the temperature change is performed to estimate the load in the cooking chamber 14 of the cooking device 10.

[0102] The joint evaluation takes place, for example, in a time period in which the information of the temperature sensor 26 associated with the microwave trap 24 and the information of the cooking chamber climate value are decorrelated, i.e. are still independent of each other, since the temperature sensor 26 has not yet been heated by the temperature in the cooking chamber 14. In particular, the corresponding time period is immediately after the microwave source 20 is switched on, for example in a time period of ten seconds to 40 seconds after the microwave source 20 is switched on.

[0103] In particular, a predefined buffer time is first waited for, for example a buffer time of 6, 10 or 15 seconds after the microwave source 20 of the cooking device 10 is switched on.

[0104] In principle, however, a longer period of time can be considered, so that the cooking chamber climate value and the gradient of the temperature change are considered for a defined period of time, for example for 120 seconds. It is thus ensured that sufficient information is available, even if only a time period of, for example, ten seconds to 40 seconds after switching on the microwave source 20 is used for the evaluation itself.

[0105] The at least one cooking chamber climate value of the climate sensor can be used by the evaluation unit 34 to determine a load controller value (LRW). Typically, an actual cooking chamber climate value and a historical cooking chamber climate value are used for this purpose to determine the load controller value (LRW).

[0106] Furthermore, the evaluation unit 34 can use information relating to the cooking program running, for example information relating to the food to be cooked 12. Accordingly, the at least one cooking chamber climate value and the gradient of the temperature change can be evaluated in a weighted manner during the joint evaluation, with weighting factors specific to the type of food to be cooked being used for the two uncorrelated sensor data. This ensures that optimized load prediction is possible, as for poultry, for example, a 70/30 weighting of the two sensor data provides the most accurate prediction, whereas for bread rolls, a 10/90 weighting provides the most accurate prediction.

[0107] This is because certain types of food to be cooked may have a low load in the load controller value but can be well estimated via the load sensor assembly 28, whereas other types of food to be cooked can be better mapped by the LRW. This is taken into account accordingly via the weighting factors specific to the type of food to be cooked.

[0108] In principle, the evaluation unit 34 is configured to evaluate both pieces of information together, i.e. that of the cooking chamber climate value and the temperature of the microwave trap 24 detected by the temperature sensor 26, such that a two-dimensional feature space is formed, in which a classification or grouping is carried out to estimate the corresponding load in the cooking chamber 14.

[0109] An exemplary two-dimensional feature space is shown in FIG. 4, in which based on the cooking chamber climate value, the load controller value (LRW) has been previously determined, which is one feature of the two-dimensional feature space. The other feature of the two-dimensional feature space corresponds to the gradient of the temperature change of the temperature sensor 26 associated with the microwave trap 24, which has been abbreviated as iMW in FIG. 4.

[0110] In FIG. 4, corresponding classifications or groupings are shown by means of dashed lines, by means of which a differentiation of the load introduced into the cooking chamber 14 is possible in a correspondingly automated manner via the evaluation unit 34.

[0111] FIG. 4 shows the two-dimensional feature space for the food to be cooked 12 “poultry”, so that the weighting factors specific to the type of food to be cooked have been taken into account for this type of food to be cooked to make the feature space correspondingly meaningful, i.e. to enable defined decision limits. These can be formed within the two-dimensional feature space by straight lines or by curves, as can be seen in FIG. 4.

[0112] The two-dimensional feature space comprises several test series, which also have outliers. Ideally, the individual load groups, i.e. 1, 2, . . . or 6 trays, would namely group (“cluster”) in this 2D feature space consisting of LRW and iMW. However, tests 446, 448 and 449 are “outliers”.

[0113] However, tests 446 and 448 only constitute outliers with respect to the feature iMW, i.e., the slope of the temperature of the temperature sensor 26 associated with the microwave trap 24 after insertion of the microwave source 20, but not with respect to LRW.

[0114] It should be noted here that the larger the slope of the temperature, i.e. the larger the iMW, the smaller the (dielectric) load. However, for the feature LRW, it can be said that the greater the LRW, the greater the (thermal) load.

[0115] Test 449 was correctly estimated with respect to the feature iMW, since the value of iMW, “−0.38”, is similar to the values of tests 407 and 412, which also represent a load of six trays. However, the value of LRW (˜55) for test 449 is more in the range of a loading of three trays, even though test 449 includes a loading of six trays.

[0116] However, the decision limits are appropriately present to make a correct prediction.

[0117] In principle, the evaluation unit 34 may also comprise an artificial intelligence 36, for example a machine learning model or a neural network, in particular a recurrent neural network, i.e. a feedback neural network.

[0118] Accordingly, the artificial intelligence 36 may have been previously trained to automatically determine correlations of the received information and to make appropriate evaluations or predictions. In this respect, at least one future value for the cooking chamber climate and/or the gradient of the temperature change may be predicted.

[0119] Thus, the artificial intelligence 36 can determine a current climate trace based on the current cooking chamber climate and the past climate to predict the future course based on the current climate trace. For example, the future profile of the temperature of the temperature sensor 26 associated with the microwave trap 24 can be predicted, particularly without the microwave source 20 being switched on. It is thus possible to compare the actual temperature profile, influenced by the microwave source 20, with the prediction and to generate information from the difference.

[0120] In other words, with the artificial intelligence 36, it is then possible to estimate a load using only the cooking climate prediction. The microwaves generated by the microwave source 20 are then used again to specifically provoke a change in the temperature sensor 15 associated with the microwave trap 24, so that better prediction results can be obtained.