Method for operating a domestic appliance, and domestic appliance

Abstract

The invention relates to a method (S1 - S12) for operating a domestic appliance (1) equipped with at least one sensor (13, 14, 16), wherein if the occurrence of a disturbance is detected (S2) during an operating sequence of the domestic appliance (1), at least one pre-disturbance measured value recorded by the at least one sensor (13, 14) immediately before the disturbance was detected is kept available (S3), and when a termination of the disturbance is detected (S4), the disturbance duration is determined (S7), reference values for a measured value reference curve (RK) relating to the operating sequence are provided (S8) on the basis of the at least one pre-disturbance measured value which was kept available, at least one actual measured value (MW) is compared (S9) with at least one reference value at the same sequence time (t), at least one operating setting of the domestic appliance is changed (S10) in order to bring the actual measured values into agreement with the reference values, and when the actual measured values have been brought (S11) into agreement with the reference values, the operating sequence is continued (S12) using the settings which would be present in the absence of a disturbance.

Description

[0001] Method for operating a household appliance and household appliance

[0002] The invention relates to a method for operating a household appliance equipped with at least one sensor, in which the occurrence of a fault is detected during an operating sequence of the household appliance. The invention also relates to a household appliance configured to carry out the method. The invention is particularly advantageously applicable to cooking appliances, especially ovens and / or steam cookers.

[0003] Sensor-supported operating procedures or processes are being implemented more and more frequently in household appliances, particularly cooking appliances. Sensor-supported operating procedures can be understood in particular as operating procedures that are monitored by at least one sensor and / or controlled or regulated by at least one sensor. For example, sensors are known for use in cooking processes that measure temperature, humidity or the concentration of individual gas components (e.g. O2, CO2, NH3, VOC, etc.) in a cooking chamber. For example, using suitable algorithms and / or models (e.g. based on artificial intelligence methods), the current condition of the food being cooked is determined from these measured values. By means of sensor-supported monitoring of an operating procedure, for example,The treatment status of the item being treated by the household appliance can be determined, and from this, for example, the end of the operating cycle can be determined. For example, during a cooking cycle, the degree of doneness of the item and thus—with knowledge of the associated target values—the end of cooking can be determined. Examples of such sensor-supported operating cycles are described in EP 2 618 064 B1 and DE 10 2004 037 606 A1.

[0004] The disadvantage is that such sensors react sensitively to changes or disturbances in their environment, such as the cooking chamber atmosphere. User-induced changes in the cooking chamber atmosphere can noticeably alter the associated measurement signal and thus disrupt or even prevent proper evaluation of the cooking process.

[0005] When an oven door is opened, an exchange occurs between the cooking and ambient atmosphere. This results in a noticeable change in the sensor signal and a lasting disruption of the associated sensor logic. This can lead to a cooking process being automatically aborted. The appliance user then has the option of manually completing the cooking process based on suitable parameter settings or restarting the sensor program. The problem here is that

[0006] - the user has little or no knowledge of the progress of the cooking process to adjust appropriate parameter settings (e.g., regarding the heating type, cooking chamber temperature, and / or remaining cooking time) for the completion of the cooking process. Relevant variables relating to the progress of the cooking process may include, for example, the partial cooking stage reached, the cooking time elapsed so far, the estimated total cooking time, etc.;

[0007] - A sensor program typically assumes raw food as the starting point. Starting a program with food that is already partially cooked or cooked is not recommended. Depending on the progress of the cooking process at the time of the malfunction, the cooking result may be more or less deteriorated.

[0008] External disturbances can generally result in changes to the process environment and / or the operation of device components (e.g., a ventilation system) that are atypical for the respective operating procedure and can lead to undesired treatment effects (e.g., damage to the food during a cooking process, extended cooking time, etc.) or even the termination of the sensor-driven operating process. An external disturbance can be caused by the device (e.g., a malfunction) or by the device user themselves (e.g., opening a treatment room door).

[0009] To avoid unnecessary process interruptions or corrections, it is known to define a so-called grace period (e.g., comprising limits for duration, sensor values), within which the user can interact with the system without causing interruptions or other adjustments to operating parameters. (Example: with active baking sensors, the door of a cooking appliance can be opened during the first few minutes of a cooking process or sequence.) The disadvantage of the grace period is that restrictions on the scope of action are only partially lifted.

[0010] DE 10 2012 200 586 A1 discloses a method for controlling a cooking process in a cooking appliance, in which a gas concentration changing in the cooking appliance during the cooking process is determined, comprising the following steps: repeatedly measuring the gas concentration in the cooking appliance and comparing two successive measured values; detecting an extreme value of the gas concentration as a first switch-off condition; continuing the measuring process for a period of time after detecting the extreme value; and triggering a cooking appliance function if, after detecting the first switch-off condition, at least one further switch-off condition is met within the period of time.

[0011] DE 10 2012 210 749 A1 discloses a cooking appliance with a cooking chamber and at least one sensor for detecting at least one property of the cooking chamber, wherein the at least one sensor comprises at least one lambda probe. The cooking appliance can be configured to determine a moisture content from an oxygen content measured by the lambda probe.

[0012] DE 102004 037606 A1 discloses a method and an arrangement for determining the course of baking, roasting and cooking processes with or without baking, roasting and cooking products containing leavening agents, wherein in the atmosphere surrounding the baking, roasting and cooking products, the carbon dioxide content CO2 and / or NH3 and / or humidity is measured as a guide gas by means of gas sensors, wherein the sensors have at least one gas-sensitive layer which, when the target gas is present, generates a measuring signal based on a change in the work function, the resistance, the capacitance or the IR absorption.

[0013] EP 0 024 798 B1 discloses a method for controlling food heating using a cooking oven, a temperature detector for detecting the surface temperature of the food, and a selection of a relative humidity detector and a gas detector for detecting a change in the environment caused by the selection of the vapor or gas emitted by the food.Gas, wherein the method comprises the steps of heating the food until a surface temperature of the food reaches a predetermined value T1 at a time t1, subsequent heating from time t1 for a time period t0 until a time t2 when the selected one among the steam and the gas causes the environment to assume a predetermined state, and further heating for a time period tR, determined by multiplying a heating time coefficient K specific to the food by the heating time period t0. DE 102012 200 304 A1 discloses a cooking appliance equipped with a cooking chamber and with at least one sensor for detecting at least one property of the cooking chamber, wherein the at least one sensor comprises at least one lambda probe. The lambda probe can in particular protrude into the cooking chamber.

[0014] DE 102007 016 501 A1 discloses that in a method for controlling a cooking process of a product in a cooking chamber of a steam cooker, moisture escaping from the product in the cooking chamber is detected at least temporarily during the cooking process by a humidity sensor over time, wherein during a measuring phase, steam is not introduced into the steam cooking chamber and the humidity sensor is evaluated. For a predetermined cooking process with fixed times for the supply of steam, the end of cooking is determined based on the evaluation of the humidity sensor during the measuring phase. Steam is introduced into the cooking chamber during a steam phase before the measuring phase, wherein the steam supply is stopped after the steam phase and before the measuring phase during a ventilation phase, and the ventilation significantly reduces the concentration of steam in the cooking chamber.

[0015] DE 102010 060 821 A1 discloses a cooking appliance for determining at least one property of a cooking chamber atmosphere, comprising: an interior space which comprises a cooking chamber for accommodating food to be cooked and at least one second chamber, in particular a pressure chamber, separated from the cooking chamber by at least one air guide element, wherein the air guide element leaves openings between the second chamber and the cooking chamber; a heating device, preferably in the second chamber; a device for circulating the cooking chamber atmosphere via the second chamber; a measuring device connected to a data processing unit, which measuring device comprises at least one sensor for determining an absorption in at least one specific spectral range of electromagnetic radiation propagating through an atmosphere in the interior space by at least one substance contained in the atmosphere, wherein at least the sensor of the measuring device, in particular the measuring device as a whole, is arranged in the second chamber.Furthermore, a method for determining at least one property of a cooking chamber atmosphere in such a cooking appliance is provided.

[0016] DE 102012 204224 A1 discloses a household appliance, in particular a cooking appliance with a lambda probe and also a method for operating a lambda probe, wherein a step-down converter is connected upstream of the lambda probe, so that a conventional lambda probe from other technical fields can also be used in the household appliance with a supply voltage that is too high for the lambda probe.

[0017] The object of the present invention is to at least partially overcome the disadvantages of the prior art and, in particular, to make sensor-driven operating sequences of a cooking appliance more robust against external disturbances. It is also the object of the present invention to enable improved automated operation.

[0018] This object is achieved according to the features of the independent claims. Preferred embodiments can be found in particular in the dependent claims.

[0019] The object is achieved by a method for operating a household appliance equipped with at least one sensor, in which

[0020] - a fault is detected during the operation of the household appliance,

[0021] - at least one measured value recorded immediately before the fault is detected by the at least one sensor (hereinafter referred to without restriction of generality as "pre-fault measured value") is retained,

[0022] - the fault is detected to end,

[0023] - a duration of the disruption is determined,

[0024] - based on at least one pre-fault measured value, a measured value reference curve (with corresponding reference values) relating to the operating process is provided,

[0025] - a comparison of at least one actual measured value with at least one reference value of the measured value reference curve is carried out at the same time,

[0026] - at least one operating setting of the household appliance is changed in order to bring the actual measured values ​​into line with the reference values ​​at the same time and

[0027] - When the actual measured values ​​have been brought into line with the reference values ​​at the same time, the operation continues with the settings that would have been in place without a fault. This procedure offers the advantage of quickly restoring the operating state to the normal operating state, which in turn supports the proper continuation of the sensor-assisted operation and prevents fault-related performance deterioration. In general, the procedure also increases user confidence in sensor-assisted operations, user satisfaction, and trust in the household appliance.

[0028] The operation of the household appliance can, in principle, comprise any operating sequence of the household appliance, in particular, but not limited to, a sequence for treating goods ("goods to be treated"). Thus, the operating sequence can also be a self-cleaning sequence. The operation of the household appliance particularly comprises an operating sequence supported by the at least one sensor or using the at least one sensor. For example, the at least one sensor can be used to control or regulate the operating sequence. The operating sequence can be an operating program.

[0029] The household appliance can be, for example, a cooking appliance, a laundry care appliance, a dishwasher, or a refrigerator. The household appliance comprises, in particular, a treatment chamber for treating the items to be treated, e.g., placing items in a cooking chamber, a laundry drum, a rinsing chamber, a refrigerator, etc.

[0030] A malfunction can be understood, in particular, as a malfunction or user intervention that may impact the outcome of the operation, particularly the item being treated. The malfunction may, in particular, result in a noticeable change in the atmosphere of the treatment room, which in turn may impair the treatment outcome.

[0031] The detection of the occurrence of a fault can be detected, for example, by the at least one sensor that is used to control or regulate the operating process, and / or in another way, e.g. by other sensors such as a door opening sensor, etc. It is a further development that the at least one pre-fault measured value recorded immediately before the detection of the fault includes at least the last measured value recorded or measured before the detection of the fault, and in the case of several process-supporting sensors, in particular also the last measured value in each case.

[0032] A further development is that the at least one pre-fault measurement value additionally includes at least one further measurement value recorded before the fault is detected. This offers the advantage that measurement value dispersion can be better limited and / or a temporal measurement value profile can be provided and used, for example, for a simulation or extrapolation of the measured value reference curve. In particular, all measurement values ​​recorded from the start of the operating sequence until the occurrence of the fault can be used as pre-fault measurement values, which particularly simplifies a simulation or extrapolation of the measured value reference curve.

[0033] The termination of the fault can be detected analogously to the occurrence of the fault.

[0034] The duration of the disruption corresponds in particular to the period of time between the occurrence of the disruption and its cessation.

[0035] It is a further development that the measured value reference curve relating to the operating process corresponds to an estimated temporal progression of measured values ​​for this operating process, even beyond the duration of the disturbance. In particular, the measured value reference curve corresponds to a "typical" progression of measured values ​​(i.e., the reference values) for the operating process under consideration.

[0036] It is an embodiment that the measured value reference curve is provided in that, for the relevant operating sequence, a measured value reference curve which best matches the at least one pre-fault measured value is selected from a group of several measured value reference curves, for example in the manner of a selection of a characteristic curve from a family of characteristics.

[0037] It is an alternative or additional embodiment that the measured value reference curve is provided by extrapolating a measured value reference curve from the course of several measured pre-fault measured values, in particular by simulating reference values ​​beyond the time of occurrence of the fault and / or by a curve adjustment or a curve fit of a curve with a known basic shape.

[0038] It is a further development that the measured value reference curve depicts the course of reference values ​​up to a regular end of the operating process, in particular from the occurrence of the fault, in particular over the entire course of a regular operating process.

[0039] The comparison of at least one actual measured value with at least one reference value of the measured value reference curve at the same time point is carried out, in particular, immediately after the disturbance has ended. The result of the comparison corresponds to the difference (e.g., in range / amplitude / magnitude) in the values ​​between the real, disturbance-affected actual measured values ​​and the reference values ​​estimated from the undisturbed measured value reference curve. The difference therefore also represents a measure of the severity of the disturbance. For minor disturbances, the difference will generally tend to be smaller than for major disturbances.

[0040] The changed operating setting or device setting is suitable for influencing the actual measured values ​​under consideration such that they can be brought into line, at least in principle, with the reference values ​​of the measured value reference curve. The operating setting or device setting can in particular comprise a change in the operation of at least one correspondingly designed functional device of the household appliance, e.g. switching on or off, changing a power level, etc. For example, a changed operating setting can change the atmosphere in the treatment room or vary it in a different way than without changing the operating setting. The changed operating setting can, for example, vary a heating output, a moisture input, a moisture content, an oxygen content, a cooling output, etc.It is therefore a possible embodiment that the at least one operating setting of the household appliance is changed by changing the control of at least one functional device of the household appliance that influences the actual measured values. It is an embodiment that, in the case of a cooking appliance, the at least one functional device comprises at least one device from the group: ambient fan, evaporator, gas cartridge and / or heating element. This makes it possible to effectively vary, for example, the cooking chamber temperature and / or the oxygen content and / or the humidity. An ambient fan can be understood in particular as a fan or ventilator by means of which gas can be conveyed from the cooking chamber into the environment (e.g. a vapor fan) and / or ambient air can be introduced into the cooking chamber (e.g. an air supply fan). The evaporator can be an evaporator located in the cooking chamber or an evaporator located outside the cooking chamber.The contents of the gas cartridge can be introduced into the cooking chamber, for example, via a controllable valve. The heating element can comprise, for example, a bottom heat element, a top heat element, a grill element, and / or a ring heater. A functional device can also be a microwave generator. A further functional device can be a circulating fan, which can be used, for example, to quickly adjust the spatial conditions in the cooking chamber.

[0041] Bringing the actual measured values ​​into line with the reference values ​​of the measured value reference curve at the same time of execution can also include bringing them into line within certain, particularly specified, tolerance ranges. The operating sequence can then be continued with those settings (particularly including operating settings or device settings) that would have been present had the fault not occurred, e.g., settings that existed before the fault occurred.

[0042] The procedure can be performed in the order listed above, but is not limited to it. The measured value reference curve can also be provided when the disturbance occurs, during the disturbance, or immediately after the disturbance has ended.

[0043] In one embodiment, the household appliance is a cooking appliance having a cooking chamber, and the fault affects a cooking process. This allows, among other things, the advantage of quickly restoring the equilibrium between food and cooking atmosphere that would have existed without a fault. A sensor-assisted cooking process can advantageously be ended using an algorithm or model that was originally used before the fault. Applying the method reduces the number of process interruptions and thus the need for manual follow-up operations. This can, for example, mean that a user is relieved of the burden of searching for suitable settings for manual operation. The associated uncertainties are avoided. Restarts of a cooking process and the associated deterioration in performance, e.g. of a cooking result, can be better avoided.Further advantages include low cost and adaptation effort, easy implementation of upgrades, and potential for optimization or redesign of cooking programs, e.g., after turning the food. Such a household cooking appliance can be, for example, an oven, a steamer, a microwave, etc., or any combination thereof, e.g., an oven with a switchable steamer and / or microwave function.

[0044] It is an advantageous embodiment, particularly in the case of a cooking appliance, that the at least one sensor comprises at least one sensor from the group

[0045] - oxygen sensor,

[0046] - Humidity sensor,

[0047] - Cooking chamber temperature sensor,

[0048] - core temperature sensor,

[0049] - chemical sensor,

[0050] - Cooking chamber camera, whereby in a further development, a sensor can also serve as a multiple sensor, for example, a lambda probe as an oxygen sensor and / or humidity sensor. The chemical sensor can be provided, for example, to detect volatile substances that can provide an indication of the degree of cooking of a cooking product, for example, substances occurring during a Maillard reaction, in particular VOCs. The camera can be used, for example, to determine the degree of browning of the cooking product.

[0051] One embodiment includes a check to determine whether the duration of the disruption has reached or exceeded a predetermined threshold. If this is the case, the operating sequence is not automatically continued, and if this is not the case, the above method is continued. This advantageously avoids giving a user the impression that the treatment sequence can be restored or saved if the disruption lasts too long to continue with the above method. The threshold can depend on the type of current operating sequence and / or the type of item being treated (e.g. its type, quantity, weight, etc.). One embodiment includes a termination of the operating sequence if the duration of the disruption has reached or exceeded the threshold. This prevents incorrect treatment of the item being treated in a particularly simple and effective manner.It is a further development that in this case a corresponding message is issued to a user, e.g. about the existence of a fault, termination of the current operational process, etc.

[0052] In one embodiment, the operating sequence is a treatment sequence, in particular a cooking sequence, for treating an item to be treated, in particular a food to be cooked, and the measured value reference curve is determined as a function of at least one property of the item to be treated. This allows the treatment sequence to be recreated even better. In the case of treating food to be cooked, the measured value reference curve can be determined, for example, as a function of a type of food to be cooked (e.g. meat, fish, vegetables, casserole, etc.), its weight, size, caliber and / or a treatment type (e.g. grilling, hot air treatment, etc.). In the case of dishware, the measured value reference curve can be determined based on the type of dishware, such as pots, glasses, etc. In the case of chilled goods, the measured value reference curve can be determined based on the type of chilled goods in the cooling chamber.

[0053] One embodiment is that the occurrence and / or termination of the fault is detected by evaluating a gradient of the actual measured values, a sign of the gradient, and / or a range / amplitude of the actual measured values. In particular, a fault can be detected if one or more of these variables deviate from typical values ​​of an operating process.

[0054] An additional or alternative development is that the occurrence and / or termination of the fault is detected by evaluating sensor data from additional sensors (in particular those not used to control or regulate the operating sequence), such as a door contact switch. If, for example, a door contact switch signals that a treatment room door is open, a fault has occurred. The object is also achieved by a household appliance configured to carry out the method described above. The household appliance can be designed analogously to the method, and vice versa, and has the same advantages.

[0055] The above-described properties, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following schematic description of an embodiment, which is explained in more detail in connection with the drawings.

[0056] Fig.1 shows a sectional side view of a sketch of a household cooking appliance in the form of an oven;

[0057] Fig.2 shows a possible sequence of the method according to the invention using the oven from Fig.1;

[0058] Fig. 3 shows a typical measured value reference curve of an oxygen sensor for a cooking process in the oven shown in Fig. 1 with deviating oxygen measured values ​​in the case of temporary disturbances without use of the method according to the invention; and

[0059] Fig.4 shows, in a representation analogous to Fig.3, the course of the measured value reference curve with deviating oxygen measured values ​​in the case of temporary disturbances using the method according to the invention.

[0060] Fig. 1 shows a sectional side view of a household cooking appliance in the form of an oven 1 with a cooking chamber 3 that can be closed by a front door 2. The cooking chamber 3 can be heated by means of a top heat element 4, a bottom heat element 5 and / or a ring heater 6. The ring heater 6 is arranged near a circulating air fan 7, for example to enable hot air operation. The oven 1 can optionally further comprise an evaporator 8, by means of which steam can be conducted into the cooking chamber 3. The oven 1 can also comprise a gas-filled cartridge 9, the contents of which can be conducted into the cooking chamber 3 through a controllable valve 10. The oven 1 further comprises an air duct 11 that is coupled to a fan 12. When the fan 12 is activated, gas or vapors can be extracted from the cooking chamber 3 and / or ambient air can be forced into the cooking chamber 3.Alternatively, several fans with different functions (suction or pressure) can be used (not shown). Flaps (not shown) can also be used to vary the cross-section of the air duct 11.

[0061] The atmosphere in the cooking chamber 3 can be monitored by two sensors 13, 14, namely an oxygen content and / or a moisture content by means of a lambda probe 13 and a cooking chamber temperature by a temperature sensor 14. In addition, for example, a core temperature sensor, a chemical sensor and / or a cooking chamber camera (not shown) can be present. The baking oven 1 furthermore has a data processing device in the form of a control device 15, which can control the functional units 4 to 12. The control device 15 is further connected to the sensors 13, 14 in order to use, in particular to evaluate, their measurement data. The control device 15 can in particular be configured to control operating sequences of the baking oven 1. Operating sequences can in particular also include operating programs. Operating sequences can include cooking sequences or other (non-)cooking sequences, e.g. self-cleaning sequences such as pyrolysis, ecolysis, etc.

[0062] The control device 15 is further connected to a door contact switch / door opening sensor 16 (e.g. a microswitch, Hall sensor, etc.), by means of which an open or closed state of the cooking chamber door 2 can be detected.

[0063] The control device 15 is furthermore configured to detect the occurrence of a fault, for example a door 2 being opened during a cooking process, based on the measurement data of the sensors 13, 14 and / or 16.

[0064] Fig.2 shows a possible sequence of the method using the oven 1 .

[0065] In a first step S1, an operating sequence in the form of a cooking process, e.g., an automatic cooking program, is started. The control device 15 controls the cooking process based on the lambda probe 13 and / or the temperature sensor 14, in particular by regulating the cooking process using the measured data as feedback variables. The control device 15 monitors for any disruption to the cooking process, in particular using the measured values ​​or signals from sensors 13, 14, and / or 16. The measured values ​​from sensors 13 and / or 14 are also stored, specifically at least the most recently recorded measured values ​​or several most recently consecutively recorded measured values, possibly even back to the start of the cooking process.

[0066] In step S2, the system monitors for the occurrence of a fault.

[0067] If a fault is detected or recognized in step S2, the last measured values ​​saved before the fault occurred are then retained in step S3 as pre-fault measured values ​​and, if necessary, saved separately or not deleted.

[0068] In step S4, the disturbance duration is calculated and checked whether the disturbance duration has reached or exceeded a predetermined threshold or not.

[0069] If the fault duration has reached or exceeded the specified threshold ("Y"), the cooking process is terminated in step S5 and a user message is issued.

[0070] Otherwise ("N"), step S6 checks whether the fault has ended or not.

[0071] If the fault persists ("N"), the system branches back to step S4.

[0072] If it was determined in step S6 that the disturbance has ended ("Y"), the disturbance duration of the disturbance that ended before the threshold value is reached is determined in step S7, if this has not already been or can be derived from step S4.

[0073] In step S8, a measured value reference curve RK (also simply referred to as "reference curve") of reference measured values ​​("reference values") for the cooking process up to the disturbance is provided from the pre-disturbance measured values, e.g. from historical data, simulation, curve fitting, combinations thereof, etc., in particular by extrapolation from the pre-disturbance measured values.

[0074] In step S9, the deviations of the actual measured values ​​MW measured by the sensors 13 and / or 14 after the fault has ended are compared with the reference values ​​of the respective measured value reference curve RK that are simultaneous with respect to the cooking process.

[0075] In step S10, at least one operating setting is determined based on this deviation(s).

[0076] Oven 1 is changed in order to bring the actual measured values ​​measured by sensors 13 and / or 14 into line with the reference values ​​at the same respective time point. For example, to compensate for a drop in the cooking chamber temperature caused by the disturbance, heating element 4, 5, and / or 6 can be switched on or set to a higher heating output. The additional amount of energy introduced can be adjusted depending on the deviation of the actual measured values ​​of temperature sensor 14 from the concurrent reference values ​​of the associated reference temperature measurement curve. Additionally or alternatively, an increase in the oxygen value (oxygen partial pressure) above the reference value detected by lambda sensor 13 can be compensated for by introducing steam into the cooking chamber 3 using evaporator 8, etc.

[0077] In step S11, a check is made to determine whether the actual measured values ​​have been brought into sufficiently accurate agreement with the reference values ​​at the respective cooking time. If this is not yet the case ("N"), the system branches back to step S10 or, as shown, to step S11.

[0078] However, if this is the case ("Y"), in a step S12 the system returns to the sensor-assisted cooking process that existed before the fault occurred, in particular taking into account the current cooking time, e.g. by adjusting a timer.

[0079] Fig.3 shows, as a plot of an oxygen content or an oxygen partial pressure p(Ü2) of the atmosphere in the cooking chamber 3 against the expiration time of a cooking process taking place, for example, in the oven 1, a typical measured value reference curve RK of an oxygen sensor, for example in the form of the lambda probe 13, with deviating oxygen measured values ​​MW in the case of temporary disturbances without use of the method according to the invention.

[0080] In order to reliably achieve and / or predict a desired cooking result using sensor-assisted cooking processes, especially cooking programs, the cooking chamber atmosphere (also referred to as the "cooking climate") should ideally exhibit a stable or food-typical profile throughout the entire cooking process or in individual cooking phases. The cooking process should therefore proceed as smoothly as possible. This is explained in more detail below using the example of a baking process for baked goods sensor-assisted by a lambda probe 13. For this purpose, it is assumed that a typical p(C>2) curve represented by the measured value reference curve RK can be divided into four phases.

[0081] The oxygen value p(C>2) remains constant in Phase I because the oxygen concentration in the cooking chamber 3 and the ambient atmosphere is the same. No water evaporation occurs from the raw baked goods. Rather, the baked goods must first be heated so that the inherent water can evaporate.

[0082] In Phase II, the oxygen value p(Ü2) decreases because the amount of water evaporated from the baked goods exceeds the amount of steam removed from cooking chamber 3. The food's own water evaporates over the baked goods surface and displaces oxygen from cooking chamber 3.

[0083] In Phase III, the oxygen value p(Ü2) remains constant, since the amount of water evaporated from the baked goods corresponds to the amount of steam removed from cooking chamber 3. The increasing drying of the baked goods surface reduces the evaporation rate compared to Phase II.

[0084] In Phase IV, the oxygen value p(Ü2) rises again, as the amount of water evaporated from the baked goods is lower than the amount of steam removed from cooking chamber 3. The evaporation of the food's own water is low, and crust formation is complete. The end of the cooking or baking process can therefore be determined by the increase in the oxygen value p(Ü2) in Phase IV.

[0085] To describe these phases, it can be assumed, in particular, that the amount of steam removed from the cooking chamber 3 remains at least approximately constant. It should also be noted that the oxygen value does not only depend on the ventilation state and the amount of water evaporated from the food, but can also depend on the amount of steam within the cooking chamber 3.

[0086] If, for example, the oven door 2 is opened in the middle or at the end of the baking process (which can be detected, for example, by the door opening sensor 16), the following two cases can occur - depending on the duration of this disturbance, the type of food, etc.: a) The oxygen level that would have existed without considering a disturbance is reached again (see the measured values ​​MW in Phase II for a disturbance between ts s tart and ts en d). The sensor-assisted cooking operation or process could then be started immediately after the fault has ended at time ts en d, maintaining the settings before the occurrence of the disturbance at time ts start. However, significantly more water is removed from the food through evaporation, as it is in a drier climate longer than necessary. This could lead to undesirable changes in the food. b) A higher oxygen level is reached than without disturbance (see the measured values ​​MW in Phase III for a disturbance between ts s tart and ts en d). The gradient of the rise in the fourth section or in phase IV of the baking process does not correspond to the gradient of the measured value reference curve RK and may not be detected at the same time.

[0087] Fig.4 shows, in a representation analogous to Fig.3, the course of the measured value reference curve RK with deviating oxygen measured values ​​in the case of temporary disturbances using the method according to the invention.

[0088] Here, after the disturbance has ended, the effects of the preceding disturbance are actively counteracted by the method according to the invention. For example, the oxygen values ​​p(C>2) are reduced to the corresponding reference values ​​of the measured value reference curve RK by introducing steam into the cooking chamber 3 via the evaporator 8. This can, for example, noticeably reduce the (additional) removal of water from the food caused by the disturbance. This also allows the oxygen level to be brought back to the "correct" typical value even at an advanced stage of cooking (e.g., in Phase III). The gradient of the increase in Phase IV of a baking process then corresponds again to the gradient of the measured value reference curve RK and is reliably detected.

[0089] Of course, the present invention is not limited to the embodiment shown. Thus, the steps in Fig. 2 can also be performed in a different order, for example, step S8 between steps S3 and S4, etc.

[0090] In general, "a", "an", etc., can be understood as a singular or a plural, in particular in the sense of "at least one" or "one or more", etc., as long as this is not explicitly excluded, e.g. by the expression "exactly one", etc.

[0091] A numerical value may also include the exact number stated as well as a usual tolerance range, as long as this is not explicitly excluded.

[0092] List of reference symbols

[0093] 1 oven

[0094] 2 doors

[0095] 3 Cooking chamber

[0096] 4 top heat radiators

[0097] 5 bottom heat radiators

[0098] 6 ring heaters

[0099] 7 recirculation fans

[0100] 8 evaporators

[0101] 9 cartridges

[0102] 10 Valve

[0103] 11 Air duct

[0104] 12 fans

[0105] 13 Lambda sensor

[0106] 14 temperature sensors

[0107] 15 Control device

[0108] 16 Door opening sensor

[0109] I - IV Phases

[0110] MW actual measured values

[0111] P partial pressure

[0112] RK measured value reference curve

[0113] S1 - S12 Process steps tSstart Time of detection of a fault tSend Time of termination of a fault t Time since the start of a cooking process

Claims

Patent claims 1. Method (S1 - S12) for operating a household appliance (1) equipped with at least one sensor (13, 14, 16), in which - when a fault is detected (S2) during the operation of the household appliance (1), - at least one pre-fault measurement value recorded immediately before the fault is detected by the at least one sensor (13, 14) is retained (S3), - and then, when the fault is detected to end (S4), - a disturbance duration is determined (S7), - based on at least one pre-fault measured value, reference values ​​of a measured value reference curve (RK) relating to the operating process are provided (S8), - a comparison of at least one actual measured value (MW) with at least one reference value is carried out at the same time (t) (S9), - at least one operating setting of the household appliance (1) is changed in order to bring the actual measured values ​​into line with the reference values ​​at the same time (S10) and - if the actual measured values ​​(MW) have been brought into agreement with the reference values ​​at the same time of operation (S11), the operating sequence is continued with the settings that would be present without a fault (S12).

2. Method (S1 - S12) according to claim 1, wherein the household appliance (1) is a cooking appliance having a cooking chamber (3) and the fault is a fault influencing a cooking process.

3. Method (S1 - S12) according to claim 2, wherein the at least one sensor (13, 14) is at least one sensor from the group - oxygen sensor (13), - Humidity sensor (13), - Cooking chamber temperature sensor (14), - core temperature sensor, - chemical sensor, - Cooking chamber camera included.

4. Method (S1 - S12) according to one of the preceding claims, in which it is checked whether the disturbance duration has reached or exceeded a predetermined threshold value (S5) and - if this is the case, the operation is not continued automatically (S6), and - if this is not the case, the procedure is continued (S7).

5. Method (S1 - S12) according to claim 4, in which, in the event that the duration of the disturbance has reached or exceeded a predetermined threshold value (S5), the operating sequence is terminated and, in particular, a corresponding message is issued to a user (S6).

6. Method (S1 - S12) according to one of the preceding claims, in which the measured value reference curve (RK) is provided (S8) by selecting a measured value reference curve (RK) that best fits the at least one pre-disturbance measured value from a group of several measured value reference curves (RK).

7. Method (S1 - S12) according to one of the preceding claims, in which a measured value reference curve is extrapolated from the course of several pre-disturbance measured values.

8. Method (S1 - S12) according to one of the preceding claims, in which the operating sequence is a treatment sequence for treating a material to be treated, in particular a material to be cooked (S1) and the measured value reference curve (RK) is determined as a function of at least one property of the material to be treated.

9. Method (S1 - S12) according to one of the preceding claims, in which the occurrence (S2) and / or the termination of the disturbance (S4) is detected by - a gradient of the actual measured values ​​(MW), - a sign of the gradient and / or - a stroke / amplitude of the actual measured values ​​(MW) is evaluated.

10. Method (S1 - S12) according to one of the preceding claims, in which the at least one operating setting of the household appliance (1) is changed by controlling at least one functional device (4 - 12) of the household appliance (1) influencing the actual measured values ​​in a changed manner (S10).

11. Method (S1 - S12) according to claims 2 and 10, wherein the at least one functional device (4 - 12) is at least one device from the group - ambient fan (12), - evaporator (8), - gas cartridge (9), - Radiators (4 - 6), - circulating fan (7), - Includes microwave.

12. Household appliance (1), wherein the household appliance (1) is configured to carry out the method (S1 - S12) according to one of the preceding claims.

13. Household appliance (1), wherein the household appliance (1) is a cooking appliance with a closable cooking chamber (3) and at least one cooking chamber sensor (13, 14), in particular an oven.

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