Cooking equipment and cooking methods

Abstract

A cooking device and a cooking method are disclosed. The cooking device is used to cook food on a support (e.g. in a basket) in a cooking chamber. The required cooking time is determined based solely on the temporal evolution of the cooking chamber temperature and the power of the heating device. A first less accurate estimate of the required cooking time is determined within a first time period (e.g. 90 seconds) after the heating device is switched on, and a second more accurate estimate of the required cooking time is then determined, e.g. within five minutes after the heating device is switched on.

Description

Technical Field

[0001] The present invention relates to a cooking device and a cooking method for estimating the time required to complete a cooking process. Background Art

[0002] Current cooking devices are primarily controlled by the user's selection of parameters such as time and temperature. Automatically selecting these cooking parameters would be convenient for the user and could also improve cooking results by eliminating human error.

[0003] In order to accurately control the cooking process, it is necessary to understand the key properties of the food during cooking. In particular, these key properties should allow the "doneness" to be measured or predicted during the cooking process. For example, the core temperature of a food item changes as the food is cooked. The core temperature of a food is a fundamental measure of doneness: for a certain type of food, the core temperature should be above a certain value to kill harmful bacteria that cause foodborne illness, but not too high to avoid overcooking. Therefore, to ensure safety, it is recommended to cook food for the appropriate length of time and at the appropriate internal temperature (range).

[0004] To determine if a food is cooked based on core temperature, invasive methods are possible, but these methods can damage the food while detecting the core temperature. Non-invasive methods, such as infrared sensing, have limited penetration capabilities and are therefore typically used to detect surface temperature.

[0005] It is also proposed to monitor the temperature of the cooking medium over time (rather than the actual food core temperature) and to monitor the mass of the item to be cooked over time. The mass and temperature information can be used to provide an estimate of the current food core temperature. The cooking process can then be controlled based on the predicted food core temperature.

[0006] This method is disclosed in WO 2015 / 185404.

[0007] This method and other known methods provide a way to measure "doneness" during the cooking process.

[0008] One problem is that measurement of doneness often requires many different sensing methods, and tracking doneness in a way that yields a reliable estimate of remaining cooking time can take a long time.

[0009] DE 10 2007 040316 discloses a system and method for displaying the remaining cooking time based on monitoring of the core temperature of the food. The first indication is based solely on user input, and then the cooking chamber temperature and the core temperature of the food are monitored to provide an estimate of the remaining cooking time.

[0010] Therefore, there is a need for a monitoring method that can perform doneness estimation with reduced complexity and can quickly provide information to the user regarding the remaining cooking time. Summary of the invention

[0011] The invention is based on determining the required cooking time using only the temporal evolution of the cooking chamber temperature and the power of the heating device. A first less accurate estimate of the required cooking time is determined during an initial period after the heating device is switched on, followed by a second more accurate estimate of the required cooking time.

[0012] The invention is defined by the claims.

[0013] According to the present invention, there is provided a cooking device, comprising:

[0014] Cooking room;

[0015] a food support for supporting food to be cooked, and for being installed in the cooking chamber;

[0016] a heating device for heating the cooking chamber;

[0017] a sensing device including a cooking chamber temperature sensor;

[0018] output devices; and

[0019] Controllers for:

[0020] generating, after a first time period from switching on of said heating device, a first estimate of a cooking time required for a given food item to be cooked, wherein said first estimate is based only on the time evolution of the cooking chamber temperature and the power of said heating device;

[0021] generating, after a second time period longer than the first time period, a second estimate of the cooking time required for said given food item to be cooked by the continuous cooking cycle, wherein the second estimate is again based only on the temporal evolution of the cooking chamber temperature and the power of the heating device; and

[0022] The output device is controlled to present the first estimate and then the second estimate to a user.

[0023] The cooking device is capable of determining the required cooking time using a simple device that only monitors temperature changes during the cooking time. No weight sensing, moisture sensing or imaging sensing is required. No food core temperature sensing is required either. The determined required cooking time is presented to the user. A first (less accurate) estimate is provided after a short period of time, after which the first (less accurate) estimate is updated with a second (more accurate) estimate, in particular when a longer time evolution of the temperature information is available. The determined required cooking time may also optionally be used for an automatic cooking cycle.

[0024] "Only based on the time evolution" means that the estimation uses time values ​​and related temperature values, and thus information that can be derived from a temperature-time diagram. Thus, there is timing information and temperature information.

[0025] "For a given food item to be cooked" means that information about that food item may also be considered. For example, a user may identify a "given food item" which is then mapped to a relevant algorithm for generating the first estimate and the second estimate.

[0026] "Through successive cooking cycles" means that the time estimate applies to successive cooking cycles. If a cooking cycle is interrupted, for example to stir or shake the food to be cooked, then the estimate may be invalidated at this time and a new estimate is required.

[0027] The first time period is, for example, 90 seconds or less, and the second time period is 5 minutes or less. Therefore, the user does not need to wait for a long time to get a preliminary estimate of the cooking time, and can check a more accurate estimate later when they are free.

[0028] The first and second estimates are preferably the only cooking time estimates for a given continuous cooking cycle. Therefore, the user does not receive different and conflicting information.

[0029] Instead, the information presented to the user is kept simple, with a rough estimate initially and a more accurate estimate later. Only when a cooking cycle is interrupted is a new (third, etc.) estimate required.

[0030] The cooking device may further comprise a power measurement system for measuring the power delivery of the heating device.

[0031] One approach is to use a known default power level for the heater. However, a more accurate approach is to measure the power delivery, for example by monitoring the current and voltage of the heater. This may be done only once during an initial period of heating, for example the average heating power over a period of, for example, 10 seconds, within an initial time after the heater is first switched on (e.g. within the first 30 seconds). The average heating power may be obtained after an initial stabilization period. The evolution of the heating power over time is not required. In particular, the second estimate may be obtained after a continuous period of activation of the heating device.

[0032] The cooking apparatus may also include a user interface for receiving information from a user regarding the type of food item to be cooked and identifying a given food item to be cooked.

[0033] Different time estimation algorithms may be used for different food types. The user information may relate to a selection of food type and food state (e.g. fresh or frozen), but preferably as a single user selection (e.g. frozen potato chips are one option, fresh potato chips are another). Thus, a single user selection may be all that is required.

[0034] The controller may further be adapted to:

[0035] During the interruption period before generating the second estimate, the heating device output power is changed after a predetermined heating time or when a predetermined temperature is reached.

[0036] This interruption gives additional information about the evolution of the temperature, e.g. how the temperature evolves during a short cooling period, e.g. an interruption of tens of seconds (e.g. 20 seconds). This means that the time evolution of the cooking temperature conveys more information, which for example may allow a more accurate consideration of the quality of the food being cooked. This helps to make the second estimate more accurate than the first.

[0037] For example, the controller is adapted to change the heating device output power to zero during the interruption period.

[0038] The cooking device may further comprise a fan for circulating air in or through the cooking chamber, and wherein the controller is further adapted to change the fan speed after a predetermined heating time or when a predetermined temperature is reached during an interruption period before generating the second estimate.

[0039] Thus, the interruptions may involve time periods of different fan drive conditions.

[0040] The controller is suitable, for example, for:

[0041] generating a first estimate based on the evolution of the cooking chamber temperature and the power delivery of the heating device during the first time period; and

[0042] A second estimate is generated based on the evolution of the cooking chamber temperature and the power delivery of the heating device during the second time period.

[0043] The second estimate is more accurate, at least because it exploits information about the time evolution over a longer period of time. For example, the estimate can be obtained based on applying the cooking chamber temperature measurements and the heating power delivery to an equation. The equation can be obtained by machine learning, with different equations being applicable to the first and second estimates and to different types of food to be cooked.

[0044] Cooking appliances include, for example, air fryers.

[0045] Cooking equipment may also include:

[0046] Sensors for sensing user intervention in the food during cooking,

[0047] wherein the controller is adapted to:

[0048] In response to and following the sensed intervention, performing a further estimation of the required cooking time; and / or

[0049] If the user intervenes before a second estimate of the required cooking time can be made, the manual cooking mode is implemented.

[0050] In this way, if the user intervenes, such as shaking or stirring the food being cooked, the time estimate is recalculated to maintain an accurate indication of the remaining cooking time. Thus, the continuous cooking cycle for which the second estimate was originally valid is no longer followed, and the updated estimate is appropriate.

[0051] The controller is for example adapted to implement an automatic cooking mode, the cooking time of which is based on the second estimate. Thus, cooking is automatic, but information about the remaining cooking time is also provided to the user.

[0052] The present invention also provides a cooking method, comprising:

[0053] sensing a temperature of a cooking chamber of a cooking device having a food support mounted in the cooking chamber for supporting food to be cooked;

[0054] generating, after a first time period from switching on of the heating device, a first estimate of a required cooking time for a given food item to be cooked, wherein the first estimate is based only on the time evolution of the cooking chamber temperature and the power of the heating device;

[0055] generating, after a second time period longer than the first time period, a second estimate of the cooking time required for the given food item to be cooked by the continuous cooking cycle, wherein the second estimate is again based only on the temporal evolution of the cooking chamber temperature and the power of the heating device; and

[0056] The user is presented with the first estimate and then the second estimate.

[0057] The method may include:

[0058] During the interruption period before generating the second estimate, changing the heating device output power after a predetermined heating time or when a predetermined temperature is reached; and / or

[0059] During the interruption period before generating the second estimate, the fan speed is changed after a predetermined heating time or when a predetermined temperature is reached.

[0060] The invention also provides a computer program comprising code means adapted to perform the steps of the method when run on a computer.

[0061] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] For a better understanding of the invention, and to show more clearly how the invention may be put into practice, reference will now be made, by way of example only, to the accompanying drawings, in which:

[0063] Figure 1 A known cooking device is shown;

[0064] Figure 2 Shown as a Figure 1 Improved cooking equipment for cooking equipment;

[0065] Figure 3 An example of a user interface panel is shown;

[0066] Figure 4 The correlation between humidity (y-axis) and time during the cooking process is shown;

[0067] Figure 5 shows the weight of food over time during the cooking process (y-axis);

[0068] Figure 6 A cooking device according to an example of the present invention is shown as an example of Figure 1 Improvements in cooking equipment;

[0069] Figure 7 shows how the cooking chamber temperature evolves over time and also shows the heating interruption periods;

[0070] Figure 8 A first cooking method is shown; and

[0071] Fig. 9 A cooking method according to the invention is shown. DETAILED DESCRIPTION

[0072] The invention again provides a cooking device for cooking food on a support, for example in a basket, in a cooking chamber. The required cooking time is determined solely on the basis of the temporal evolution of the cooking chamber temperature and the power of the heating device. A first less accurate estimate of the required cooking time is determined within 90 seconds after the heating device is switched on, and a second more accurate estimate of the required cooking time is then determined within five minutes after the heating device is switched on.

[0073] For example, the present invention is of interest for application to air fryers.

[0074] Figure 1 There is shown a cross-sectional view of a known design of an air based fryer 1. The air based fryer 1 comprises a cooking chamber 2 having side walls 3, a bottom wall 4 and a top wall 5. A food support in the form of a basket 10 is provided within the cooking chamber 2 to support food F to be cooked.

[0075] The basket 10 comprises an air permeable bottom 12 and solid side walls 14. It has an open top, but a permeable cover may also be provided. The bottom 12 comprises, for example, a wire mesh which snaps into the base of the basket within the side walls 14. The wire mesh may be removed, for example, for cleaning in a dishwasher, while the rest of the basket is typically wiped clean by the user.

[0076] A mounting structure 15 is provided to detachably mount the basket 10 in the cooking chamber 2. The mounting structure 15 is designed to allow air to circulate completely around the basket 10 in the mounted state. The mounting structure 15 is designed so that in the mounted state, a bottom gap 16a is provided between the air permeable bottom 12 and the bottom wall 4 of the cooking chamber 2. In addition, a lateral gap 16b is provided between the side wall 3 of the cooking chamber 2 and the periphery of the air permeable bottom 12. The bottom gap 16a and the lateral gap 16b together form a part of the air circulation channel.

[0077] The mounting structure 15 is designed to minimize obstruction to the air circulation passage.

[0078] In some embodiments, Figure 1 As shown, the mounting structure 15 includes a handle by which the basket 10 can be hung on the side wall 3 of the cooking chamber 2. The handle allows the user to easily remove the basket 10 from the cooking chamber 2.

[0079] The air-based fryer 1 further includes an air circulation system for circulating hot air in the cooking chamber 2, the air circulation system including a fan 17, a motor 19, and an air heater 18. The air heater 18 may be disposed above the basket 10. In this case, the air heater 18 may radiate heat directly to the food materials F in addition to heating the air in the cooking chamber 2.

[0080] An air circulation system may also be disposed above the basket 10 , such as above the air heater 18 .

[0081] The air circulation system is designed to pass hot air through the air permeable bottom 12 of the basket 10 so that food F placed on the bottom will be prepared by the flow of hot air therethrough.

[0082] The air circulation system in this example is designed to draw air upward through the basket 10, as shown by arrows 13. The air may then flow along the air heater 18 to heat the air. The air heater 18 may be any suitable heating source, such as an electric heater that can heat the air to, for example, between about 100° C. and 250° C. by controlling the power supplied to the air heater.

[0083] As shown by arrow 11, the air circulation system is designed to make hot air flow downward along the inner surface of the cooking chamber 2 and the outer surface of the basket 10. The bottom gap 16a and the side gap 16b together form an air circulation channel for guiding the hot air flow from the air circulation system to the bottom 12 of the basket 10.

[0084] The bottom wall 4 of the cooking chamber 2 may be flat or may be Figure 1 As shown, the bottom wall 4 may be provided with an air directing member 20 configured to direct a flow of hot air toward and / or through the air permeable bottom 12 of the basket 10 .

[0085] The air guiding member 20 may have a generally conical or frustoconical outer profile, or it may comprise ribs or arms.The air guiding member 20 may be integrally formed in the bottom wall 4 of the cooking chamber, or provided as a separate insert.

[0086] In the example shown, a deflector plate 24 is provided above the basket 10 in the upper portion of the cooking chamber 2 to further surround the volume enclosed by the basket 10 and to help guide air from the air circulation system around the basket into the air circulation channel formed by the bottom gap 16a and the lateral gap 16b.

[0087] The cooking chamber 2 is shown as having an upper portion 2a and a lower portion 2b that are separable from each other to enable access to the interior of the cooking chamber 2. Thus, the upper portion 2a functions as a cooking chamber cover. In some embodiments, the lower portion 2b may be arranged to be fixed, while the upper portion 2a may be arranged to be releasable or hinged, such as in the form of a lid. In some embodiments, the upper portion 2a may be arranged to be fixed, while the lower portion 2b may be arranged to be releasable, such as in the form of a drawer. In this case, the lower portion 2b may include a handle 22 to help remove the lower portion 2b from the air-based fryer 1, such as Figure 1 As shown, handles 15 and 22 are connected together to define a single handle for operation by a user.

[0088] The air based fryer 1 may include a vent (not shown) defining an air outlet from the cooking chamber 2 to the exterior of the air based fryer 1 .

[0089] In use, a variety of food types can be prepared in the air-based fryer 1. In the case of bulk food, the individual food ingredients F can be formed into Figure 1 The stack is shown with the height, density and therefore flow resistance of the stack being highest in the centre of the stack and decreasing towards the periphery.

[0090] The bottom 12 of the basket 10 can, for example, be designed to have a flow resistance that inversely reflects the flow resistance of the pile, and is therefore lowest in the center and gradually increases toward the periphery. Thus, the total flow resistance of the bottom 12 and the pile together can remain more or less constant over the entire cross-section of the basket 10, resulting in a more uniform airflow through the basket 10 and ultimately a more uniform cooking result.

[0091] The heater is controlled by a controller ( Figure 1 The controller (not shown) obtains temperature information from the temperature sensor 30a, thereby performing feedback control on the heating process.

[0092] The present invention can be applied to different types of cooking equipment, including Figure 1 's air fryer designs, other air fryer designs, or indeed other types of cooking equipment.

[0093] The invention more generally relates to a cooking device having a cooking chamber, a food support for mounting in the cooking chamber to support food to be cooked, and a heating device for heating the cooking chamber.

[0094] A first aspect of the present disclosure relates to the detection of an interruption of a cooking cycle.

[0095] Figure 2 It shows how to improve the Figure 1 cooking equipment.

[0096] The cooking device also includes a sensing device for sensing cooking parameters over time. For example, the cooking parameters may include one or more of the following:

[0097] The cooking chamber temperature measured by the temperature sensor 30a (or a set of temperature sensors at multiple locations in the cooking chamber) within the cooking chamber. Note that this can be an existing temperature sensor used for feedback control of the heating process, or there may also be one or more additional dedicated sensors;

[0098] humidity measured by humidity sensor 30b within the cooking chamber (or a set of humidity sensors at multiple locations within the cooking chamber);

[0099] the weight of the food as determined by a weight sensor 30c for weighing the basket;

[0100] The color (or related appearance characteristics) of the food monitored by the image sensor 30d;

[0101] The weight of the food is determined by a weight sensor 30e for weighing the basket and the cooking chamber 2.

[0102] Note that any combination of sensors can be used in this regard. Any one can be used alone, or any combination of different sensing modes can be used. For example, preferred combinations include temperature and weight monitoring, humidity and weight monitoring, humidity and temperature monitoring. Any combination of two or three sensing modes can be used, and all four sensing modes can also be used.

[0103] The controller 32 (typically implemented as a microprocessor) is adapted to determine the cooking time required for the food to be cooked based on the time evolution of one or more sensed cooking parameters. It receives sensing signals from the sensing devices 30a, 30b, 30c, 30d, 30e, although these signal paths are not in Figure 2 Shown in.

[0104] The function used to determine the cooking time will depend on the sensing mode used and can be based on machine learning or using equation-based modeling of cooking characteristics. A lookup table can be used instead. Basically, any mapping between parameters sensed over time and the estimated remaining cooking time can be used. The time evolution of the parameters is monitored, for example, over a measurement period of time. From the data obtained, a function can be fit to the data and the function can be extrapolated into the future. The function can, for example, represent the food core temperature, and the target core temperature corresponds to the completion of the cooking process. The function can be a linear approximation or a higher-order function. However, there may instead be a target humidity level, a target image feature (such as color), or other target conditions representing the completion of the cooking process.

[0105] The controller 32 controls a panel 34 that functions as a user interface for receiving user commands and displaying output to the user.

[0106] like Figure 3 As shown, the panel 34 has, for example, a rotary control knob 36, an on / off button 38, a selection button 40 (for selecting the option selected by the knob 36), and a display 42. For example, the display has areas for displaying the cooking temperature setting, the time remaining in the cooking process, and a symbol indicating that it is time to shake the food, i.e., remove the basket from the cooking chamber and shake the contents to achieve a better overall cooking process. Thus, an output instruction is provided to the user to perform an intervention at a specific time. This may be a visual output or an auditory output.

[0107] Of course other displays can be provided, such as food type (fish, meat, vegetables, chips). The user can enter the food type and fresh or frozen status.

[0108] Back to Figure 2The cooking device also has a sensor 50 for sensing user intervention with the food during the cooking process. The sensor may detect the opening of the lid or the removal of the drawer. In either case, it senses when the basket is removed. The sensor is Figure 2 30a, 30b, 30c, 30d may be used as discussed further below.

[0109] The controller 32 redetermines the desired cooking time based on the time evolution of the sensed cooking parameters in response to and following the sensed intervention.

[0110] In this way, the cooking device determines the cooking time based on the evolution of one or more of the cooking parameters (e.g., chamber temperature, food core temperature, humidity level, food weight, image features, etc.). By sensing an intervention, such as shaking the food ingredients, the cooking time can be recalculated to take into account the intervention. Thus, the indication remains accurate and / or the automatic cooking process remains reliable. Thus, the determination of the cooking time does not need to be performed continuously, saving time and processing. Instead, the determination of the remaining time occurs at discrete times, in particular at the beginning of the cooking process and when one or more sensed interventions are completed.

[0111] It is known that the time evolution of cooking parameters can be used to determine the remaining cooking time.

[0112] A first possible method is to use a probe to monitor the food core temperature over time. This is based on an analysis of the heat transfer function between the air in the cooking chamber and the food as the food heats up and is cooked. For example, by monitoring the temperature at a set of time intervals, a function can be obtained by interpolating between these values, and the end cooking time can be obtained by extrapolation of this function. For example, the cooking process is complete when the food core reaches a certain temperature.

[0113] For example, a system based on this method is described in EP 1 835 371, to which reference is made in the present application. However, this requires that a temperature probe be inserted into a portion of the food.

[0114] Another approach is to monitor one or more cooking chamber temperatures and estimate the core temperature based on these external temperature measurements. For example, additional monitoring of the weight of the food may allow an accurate estimate to be achieved. The weight sensor 30c monitors, for example, the weight of the basket and the food to be cooked, or even the weight of the entire cooking appliance (in which case it may be located outside the cooking chamber). The weight sensor 30c may be implemented as a pressure sensor.

[0115] The controller 34 processes the weight sensor and temperature sensor information to provide a prediction of the food core temperature and determines the cooking time by extrapolating the predicted food core temperature.

[0116] In this way, core temperature prediction can be achieved using parameters that are readily available in the cooking system. Other parameters can be monitored, including humidity. For example, the parameters can include air temperature, or a combination of air temperature change rate, food surface temperature, food surface temperature change rate, food weight, food weight loss rate, food moisture content, moisture content change rate, ambient air humidity, humidity change rate, etc.

[0117] These parameters can be detected, determined or estimated without intruding or destroying the food.

[0118] First, the relationship between the core temperature and the entire set of monitored parameters is established, and then the core temperature can be predicted based on this relationship. The predicted core temperature can then be used to determine the cooking state of the food and can therefore be used to control the process and obtain the remaining cooking time.

[0119] This method is described in more detail in WO 2015 / 185404.

[0120] It is also known to determine the doneness level of food based (only) on moisture sensing, as described in EP 0 701 387. The moisture content in the cooking cavity evolves over time. EP 0 701 387 discloses using a neural network to learn how the moisture function maps to the doneness of the food.

[0121] The present invention may use any one or a combination of these known methods to provide an estimate of the level of doneness of a food and predict future functions of doneness over time, thereby enabling an estimate of remaining cooking time.

[0122] The estimation may utilize any combination of chamber temperature sensing, food surface temperature sensing, food core temperature sensing utilizing a probe, chamber humidity sensing, food weight sensing, and food image analysis.

[0123] This aspect does not specifically concern the estimation of doneness or the prediction of future doneness, as known methods indicated and discussed above may be used.

[0124] The first feature is to provide an indication to the user when to intervene, typically a shake function of the basket. A specific time is set when user intervention is required and an output is generated for the user. For example, this may be halfway through the cooking time when determined based on an estimate of the total cooking time. More generally, the intervention time may be a point between one third and two thirds of the determined required cooking time. The intervention may be a set point in the cooking process, or may be based on monitoring of cooking parameters, but this will still typically result in a point between one third and two thirds of the cooking process.

[0125] The second feature is that the intervention itself is sensed by sensor 50 (or one or more of sensors 30a, 30b, 30c, 30d, as described below). The sensed intervention can be the opening of the chamber (for removing the basket or manipulating the food on the support) or the actual removal of the basket (for shaking).

[0126] As mentioned above, the intervention time does not have to be a specific portion of the cooking time.

[0127] As an example, if the sensing (used for cooking time determination) includes humidity sensing, the time of intervention can be set to the point in time when the humidity reaches a certain level. This may be before the food starts to lose moisture rapidly.

[0128] By opening the cooking chamber (eg a drawer or a lid), the humidity in the cooking chamber drops drastically. Humidity monitoring itself can therefore be used as a sensing mechanism for sensing interventions.

[0129] Figure 4 The correlation of humidity (y-axis in arbitrary units) to time (graphed as the number of 30 second cooking cycles, x-axis) is shown. The dashed line shows the effect of the intervention at about 12 cycles. Regions 60a to 60e represent different stages of doneness during the cooking process. The humidity threshold is at the end of the second stage 60b.

[0130] For example, cooking stages may include:

[0131] 60a heating water on the surface of food;

[0132] 60b Water on the food surface begins to evaporate;

[0133] 60c Surface water evaporation is complete;

[0134] 60 days of water evaporating from the food; and

[0135] 60e Weak evaporation due to food drying.

[0136] As another example, if the sensing (for cooking time determination) includes weight sensing, the time of intervention may be set to the point in time when a certain weight loss (eg 20%) occurs. To this end, weight may be monitored over time.

[0137] By lifting the basket, the sensed weight drops to zero (if the basket weight is measured by sensor 30c) or drops to a generally known degree (if the basket and cooking chamber weights are measured by sensor 30e). Thus, weight monitoring itself can be used as a sensing mechanism to sense intervention.

[0138] Figure 5 The weight of the food (y-axis, normalized to a starting weight of 1) is shown over time (x-axis, minutes). It shows that when the weight drops to 80%, it drops to zero at 9 minutes due to the intervention. This is about halfway through the cooking process.

[0139] As another example, if the sensing (used for cooking time determination) includes image sensing, such as color monitoring, the time of intervention may be set to the point in time when a certain color change occurs or a target color is reached.

[0140] By lifting the basket, the sensed color changes to the opposite wall of the cooking chamber, rather than the food item. Thus, image sensing itself can be used as a sensing mechanism to sense intervention.

[0141] If the sensing (for cooking time determination) includes chamber temperature monitoring, temperature sensing may be used as a sensing mechanism to sense intervention based on a sudden drop in temperature (ie, towards ambient temperature).

[0142] Of course, the intervention can be sensed by a dedicated sensor. For example, the sensor 50 can be a switch sensor or a proximity sensor.

[0143] Typically, a single intervention is sufficient, but it is conceivable that the system may suggest that multiple interventions are required.

[0144] Thus, the timing of the intervention is typically a function of the determined cooking time, or a function of the cooking parameter being monitored.

[0145] As described above, when an intervention is sensed, the remaining cooking time is recalculated. In this way, the doneness estimation does not need to be performed continuously. Instead, at the beginning of the cooking process, a first calculation of the remaining cooking time is performed. For example, this calculation takes 30 seconds.

[0146] There may be user input related to the type of food (e.g., fresh or frozen) that will affect the estimate. If there is no weight sensor as part of the system, the food weight (e.g., actual weight or an indication of whether the basket is half full or full) may also be input into the cooking device.

[0147] The second calculation is performed only when a tampering is detected.

[0148] This intervention may change the required cooking time, especially for cooking devices with a small cooking chamber that is not much larger than the food support. An air fryer is an example of such a cooking device. It heats up very quickly and has a small chamber. For example, the time to cook French fries may increase from 20 minutes to 25 minutes due to the intervention, especially because the cooking chamber may take 1 to 2 minutes to cool down when the basket is shaken. For example, the cooking time may be extended by 3 to 10 minutes, or by 10% to 30% of the total cooking time.

[0149] However, the adjustment of the cooking time is not just an added fixed time. Instead, it is based on a recalculation of the remaining cooking time, for example, requiring another 30 seconds of sampling of the sensor data to interpolate the new time point when cooking is complete.

[0150] If there is a second or further intervention (whether indicated by the device or merely sensed by the device), the remaining cooking time may again be recalculated.

[0151] If the cooking device recommends an intervention, but no intervention is sensed (eg, the user has to be out and therefore cannot perform the desired intervention), the cooking time does not need to be recalculated.

[0152] As mentioned above, the first aspect does not rely on any particular method of calculating doneness.

[0153] Figure 6 It shows how to improve Figure 1 One aspect of this concerns the way in which doneness and remaining cooking time are calculated.

[0154] The cooking device also comprises sensing means for sensing cooking parameters over time. However, the estimation of the required cooking time is based only on the time evolution of the cooking chamber temperature and the power of the heating device. Therefore, there is a temperature sensor 30a in the cooking chamber (or a set of temperature sensors at multiple locations in the cooking chamber). This can also be an existing temperature sensor used for feedback control of the heating process, or there can be one or more additional dedicated sensors.

[0155] The controller 32, typically implemented as a microprocessor, is adapted to determine the cooking time required for the food to be cooked based on the time evolution of the cooking temperature and the heating device power, represented as input 30f.

[0156] The heating device power may simply be the rated power of the heater (or the known powers of different heating settings), which is known to the controller. The cooking device may alternatively comprise a power measurement system for measuring the power delivery of the heating device, for example by monitoring the current and voltage of the heater. This may be done only once during an initial phase of heating, for example the average heating power during a period of, for example, 10 seconds, during an initial time after the heater is first switched on (for example, within the first 30 seconds). The average heating power may be obtained after an initial stabilization period. For example, no evolution of the heating power over time is required.

[0157] The heating power can be measured by locally monitoring the voltage and current of the heating device. However, the heating power can instead be derived from the total power consumption of the device (since the contribution of the heating device to the overall power consumption is large and known).

[0158] The function for determining the cooking time is for example based on machine learning or using equation-based modeling of the characteristics of the temperature-time function. Those equations may be generated based on machine learning during a previous learning phase of development. Again a lookup table may be used instead. The time evolution of the cooking temperature is for example monitored over a measurement period. From the data obtained, a function may be fitted to the data and this may be extrapolated into the future. The function may for example represent the food core temperature and a target core temperature corresponds to the completion of the cooking process. The function may be a linear approximation or a higher order function.

[0159] The controller 32 controls a panel 34 that functions as a user interface for receiving user commands and displaying outputs to the user.

[0160] The controller 32 is adapted to generate a first estimate of the cooking time required for a given food item to be cooked after a first time period from switching on of the heating device, wherein the first estimate is based only on the time evolution of the cooking chamber temperature and the power of the heating device.

[0161] This first estimate may be given within 2 minutes after the heating device is switched on, for example within 90 seconds or within 1 minute. It is assumed that the cooking is not based on a preheated oven.

[0162] The controller then generates a second estimate of the cooking time required for the given food item. It is assumed that cooking will be performed by a continuous (i.e. non-user interrupted) cooking cycle. The second estimate is given after a second time period that is longer than the first time period. The second estimate is also based only on the time evolution of the cooking chamber temperature and the power of the heating device.

[0163] The second estimate is given after the first estimate, for example more than 2 minutes after the heating device is switched on, but for example less than 10 minutes, and preferably less than 5 minutes after the heating device is switched on.

[0164] Panel 34 is used to present the first estimate and then the second estimate to the user.

[0165] The required cooking time is obtained by using a simple device that only monitors the temperature change during the cooking time. No weight sensing, moisture sensing or imaging sensing is required. Food core temperature sensing is also not required.

[0166] The panel 34 is used to receive information from the user regarding the type of food item to be cooked and to identify a given food item to be cooked. Different food types may use different time estimation algorithms. The user information may relate to a selection of food type and food state (e.g., fresh or frozen), but preferably as a single user selection (e.g., frozen potato chips are one option, fresh potato chips are another option). Thus, all that is required is a single user selection.

[0167] As mentioned above, the purpose of the second estimate is to present more accurate information to the user. This is possible because the evolution of the cooking chamber temperature over a longer period of time is available.

[0168] Additional steps can be taken to improve the accuracy of the second estimate.

[0169] Figure 7 A curve 70 of the cooking chamber temperature versus time is shown. The heating power is also shown as curve 72 (without scale). The heating device is switched on at time zero. Since cold or even frozen food is placed in the cooking chamber at time zero, the cooking chamber temperature initially drops. The cooking chamber temperature drops to a minimum and then increases. The shape of the curve 70 represents the evolution of the cooking chamber temperature. Therefore, any feature of the curve 70 (first derivative, second derivative, minimum, maximum, duration, etc.) can be used as a parameter for the remaining time estimation.

[0170] As described above, these features of curve 70 may be used by a pre-trained machine learning classifier.

[0171] A machine learning algorithm is any self-training algorithm that processes input data to produce or predict output data. Here, the input data includes temperature profiles, while the output data includes time estimates.

[0172] Machine learning algorithms suitable for the present invention are obvious to those skilled in the art. Examples of suitable machine learning algorithms include decision tree algorithms and artificial neural networks. Other machine learning algorithms (such as logistic regression, support vector machines or naive Bayes models) are also suitable choices.

[0173] The structure of artificial neural networks (or neural networks for short) is inspired by the human brain. Neural networks consist of multiple layers, each layer includes multiple neurons. Each neuron includes a mathematical operation. Specifically, each neuron can include a different weighted combination of a single type of transformation (for example, the same type of transformation, sigmoid, etc., but with different weights). During the process of processing the input data, the mathematical operation of each neuron is performed on the input data to produce a numerical output, and the output of each layer in the neural network is fed into the next layer in turn. The last layer provides the output.

[0174] Methods for training machine learning algorithms are well known. Typically, such methods include obtaining a training data set, including training input data entries and corresponding training output data entries. An initialized machine learning algorithm is applied to each input data entry to generate a predicted output data entry. The error between the predicted output data entry and the corresponding training output data entry is used to modify the machine learning algorithm. This process can be repeated until the error converges and the predicted output data entry is sufficiently similar to the training output data entry (e.g., ±1%). This is generally referred to as a supervised learning technique.

[0175] For example, in the case where the machine learning algorithm is formed by a neural network, the mathematical operation (weight) of each neuron can be modified until the error converges. Known methods for modifying neural networks include gradient descent, back propagation algorithms, etc.

[0176] For example, the first estimate is provided between 30 seconds and 90 seconds after switching on the heating device.

[0177] In this example, when the temperature reaches 165 degrees, the heating device output power is reduced to zero (or it can be changed to medium heating power). In this example, the heating device is turned off over a 20 second interruption period (128 seconds to 148 seconds). The time evolution of the temperature changes shape during this time, and this provides more information for the temperature estimation algorithm. For example, it can allow the quality of the food being cooked to be taken into account more accurately. The quality of the food is the main factor affecting the cooking time.

[0178] The interruption may be at a different temperature (e.g. 140 degrees, or any temperature between 120 and 190 degrees). Alternatively, it may be after a predetermined heating time.

[0179] The controller may additionally or alternatively vary the speed of the fan 17 during the interruption period after a predetermined heating time or when a predetermined temperature is reached.

[0180] The estimation is based on the evolution of the cooking chamber temperature during the previous time period (including the interruption period, if used) and the power delivery of the heating device. The second estimation is more accurate, at least because it utilizes the time evolution information over a longer period of time. However, the use of interruption periods can further improve the accuracy.

[0181] Please note that when an interruption period is designed into a cooking cycle, it is part of the "continuous cooking cycle" defined above.

[0182] Figure 8 A first cooking method is shown, comprising:

[0183] In step 80, a cooking time required for the food to be cooked is determined based on the evolution of the sensed cooking parameters over time;

[0184] In step 82, sensing user intervention with the food during the cooking process; and

[0185] In step 84 , in response to the sensed intervention, the desired cooking time is re-determined based on the evolution of the sensed cooking parameters over time.

[0186] The required cooking time may be output to the user and may also be used to automatically control the cooking process.The method may further comprise, in step 81, instructing the user to perform the intervention via a visual and / or audible output.

[0187] The above example is based on shaking the food items, such as chips in a basket, to provide better all-around cooking. However, the intervention may instead include flipping or turning the food items. For example, depending on the user's preference, one side or both sides of the food items present may be cooked, and different cooking times may be appropriate. The length of time spent by the user may also affect the required remaining cooking time. The food items may be mounted on a support, such as a pan or plate, rather than in a basket.

[0188] Thus, the type of intervention may depend on the type of cooking device.The device of the present invention typically detects intervention (and it may also provide an indication of when intervention has occurred) and then recalculates the cooking time using an interpolation / extrapolation method based on the sensed cooking parameters.

[0189] Fig. 9 A cooking method according to the present invention is shown, comprising:

[0190] In step 90, a cooking chamber temperature of a cooking device having a food support installed in the cooking chamber for supporting food to be cooked is sensed;

[0191] In step 92 , after a first time period from switching on the heating device, a first estimate of a required cooking time for a given food item to be cooked is generated, wherein the first estimate is based only on the time evolution of the cooking chamber temperature and the power of the heating device;

[0192] In step 94 the first estimate is presented to the user.

[0193] in step 96, after a second time period longer than the first time period, generating a second estimate of the cooking time required for the given food item to be cooked by the continuous cooking cycle, wherein the second estimate is again based only on the time evolution of the cooking chamber temperature and the power of the heating device; and

[0194] In step 98 the second estimate is presented to the user.

[0195] The above two aspects can be combined so that the implementation of tampering detection can be applied together with the remaining time estimation of the present invention.

[0196] These methods can be implemented in part by software running on a controller. The system utilizes a controller to implement algorithms and control the user interface and cooking cycles. Components that can be used for the controller include, but are not limited to, conventional microprocessors, application specific integrated circuits (ASICs), and field programmable gate arrays (FPGAs).

[0197] In various embodiments, a processor or controller may be associated with one or more storage media, such as volatile and non-volatile computer memory, such as RAM, PROM, EPROM, and EEPROM. The storage media may be encoded with one or more programs that, when executed on one or more processors and / or controllers, perform the desired functions. The various storage media may be fixed within a processor or controller, or may be transportable so that one or more programs stored thereon may be loaded into a processor or controller.

[0198] Variations to the disclosed embodiments may be understood and implemented by those skilled in the art in practicing the claimed invention by studying the drawings, the disclosure and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude pluralities. A single processor or other unit may implement the functions of several items listed in the claims. The fact that certain measures are recited in mutually different dependent claims does not mean that a combination of these measures cannot be used to advantage. The computer program may be stored / distributed on a suitable medium, such as an optical storage medium or solid-state medium provided with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems. The term "suitable for" used in the claims and the description is intended to be equivalent to the term "configured to". Any reference signs in the claims should not be interpreted as limiting the scope.

Claims

1. A cooking device (1), comprising: Cooking room (2); A food support (10) for supporting food to be cooked, and adapted to be installed in the cooking chamber; A heating device (18) for heating the cooking chamber; A sensing device including a cooking chamber temperature sensor (30a); Output devices; and Controller (32), suitable for: generating, after a first time period from switching on of the heating device, a first estimate of the cooking time required for a given food item to be cooked, wherein the first estimate is based only on the time evolution of the cooking chamber temperature and the power of the heating device (18); generating, after a second time period longer than the first time period, a second estimate of the cooking time required for the given food item to be cooked by a continuous cooking cycle, wherein the second estimate is again based only on the temporal evolution of the cooking chamber temperature and the power of the heating device (18); and The output device is controlled to present the first estimate and thereafter the second estimate to a user. 2 . The cooking apparatus of claim 1 , wherein the first time period is 90 seconds or less, and the second time period is 5 minutes or less.

3. A cooking device according to claim 1 or 2, wherein the first estimate and the second estimate are the only cooking time estimates for a given continuous cooking cycle.

4. The cooking device according to any one of claims 1 to 2, further comprising a power measurement system for measuring the power delivery of the heating device (18).

5. The cooking apparatus of any one of claims 1 to 2, further comprising a user interface for receiving information from a user regarding the type of the given food item to be cooked and identifying the given food item to be cooked.

6. The cooking device according to any one of claims 1 to 2, wherein: The controller is further adapted to: During an interruption period before generating the second estimate, the heating device output power is changed after a predetermined heating time or when a predetermined temperature is reached.

7. The cooking device of claim 6, wherein the controller is adapted to change the heating device output power to zero during the interruption period.

8. The cooking device according to any one of claims 1, 2 and 7, further comprising a fan for circulating air in or through the cooking chamber, wherein the controller is further adapted to change the fan speed after a predetermined heating time or when a predetermined temperature is reached during an interruption period before generating the second estimate.

9. The cooking device according to any one of claims 1, 2 and 7, wherein the controller is adapted to: generating the first estimate based on an evolution of the cooking chamber temperature during the first time period, and a heating device power delivery; and The second estimate is generated based on the evolution of the cooking chamber temperature during the second time period, and the heating device power delivery.

10. The cooking device of any one of claims 1, 2 and 7, comprising an air fryer.

11. The cooking device according to any one of claims 1, 2 and 7, further comprising: a sensor (50) for sensing user intervention in the food during the cooking process, The controller (32) is adapted to: In response to and subsequent to the sensed intervention, performing a further estimation of the required cooking time; and / or If the user intervenes before the second estimate of the required cooking time can be made, a manual cooking mode is performed.

12. The cooking apparatus of claim 11, wherein the controller is adapted to implement an automatic cooking mode, wherein the cooking time is based on the second estimate.

13. A cooking method comprising: sensing a temperature of a cooking chamber of a cooking device having a food support mounted in the cooking chamber for supporting food to be cooked; generating, after a first time period from the switching on of the heating device, a first estimate of a cooking time required for a given food item to be cooked, wherein the first estimate is based only on the temporal evolution of the cooking chamber temperature and the power of the heating device; generating, after a second time period longer than the first time period, a second estimate of a required cooking time for the given food item to be cooked by a continuous cooking cycle, wherein the second estimate is again based only on the temporal evolution of the cooking chamber temperature and the power of the heating device; and The first estimate is presented to a user, and the second estimate is then presented.

14. The method according to claim 13, comprising: During an interruption period before generating the second estimate, changing the output power of the heating device after a predetermined heating time or when a predetermined temperature is reached; and / or The fan speed is changed after a predetermined heating time or when a predetermined temperature is reached during an interruption period before generating the second estimate.

15. A computer program product comprising code means adapted to perform all the steps of claim 13 or 14 when controlling a cooking device according to any one of claims 1 to 12, when running on a computer.

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