Cooking appliance and method for preheating for cooking operations

Abstract

A method is for determining a cooking zone of an appliance is preheated. The method includes determining a cooking zone temperature setpoint based on user input. The method includes directing power to at least one heating element of the appliance based on the cooking zone temperature setpoint and detecting a sensor temperature. The method includes calculating an estimated cooking zone temperature based on the sensor temperature value. In response to the cooking zone temperature being at least equal to the cooking zone temperature setpoint, the method includes the step of indicating that the cooking zone of the appliance is preheated.

Description

FIELD OF THE INVENTION

[0001] The present subject matter relates generally to cooking appliances, and more particularly to methods of operating cooking appliances according to thermal behaviors of cooking surfaces.BACKGROUND OF THE INVENTION

[0002] Cooking appliances generally have one or more heating elements configured for heating a cooking surface. The cooking surface, e.g., a pot, a pan, a griddle, etc. may be positioned on or near the one or more heating elements and food products (including, e.g., food solids, liquid, or water) may be placed atop the cooking surface for cooking. A controller may selectively energize the heating element(s) to provide thermal energy to the cookware item and the food products placed thereon. Alternatively, certain cooking appliances, often referred to as induction cooktops, provide energy in the form of an alternating magnetic field which causes the cookware item to generate heat. In both types of appliances, a controller selectively energizes either the heating element(s) or a magnetic coil to heat the food products until they are properly cooked.

[0003] For cooking appliances that are capable of performing feedback controlled heating operations, one or more algorithms may be used to incorporate certain feedback information (e.g., absolute temperature value, temperature change, temperature rate of change, etc.) over a heating period to intelligently control a power level of the heating element(s). For instance, some heating operations may incorporate preheating phases during which the power level applied to the heating element varies according to the temperature reading at a temperature sensor and the desired temperature for a cooking zone. However, some designs may have location constraints for the temperature sensor due to manufacturing or mounting limitations, overheating, or the like. As a result, when the preheating phase begins, the temperature sensor may sense a temperature that is delayed or offset from the cooking zone temperature. Existing methods have several drawbacks, including inaccurate cooking zone temperature estimation, resulting in large discrepancies in sensed temperature, inadequate controller output, and the like.

[0004] Accordingly, a cooking appliance and method of operating a cooking appliance that obviates one or more of the above-mentioned drawbacks would be desirable. In particular, a cooking appliance capable of accurately estimating one or more parameters of a heating operation would be useful.BRIEF DESCRIPTION OF THE INVENTION

[0005] Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

[0006] In one exemplary aspect of the present disclosure, a method is for determining a cooking zone of an appliance is preheated. The method includes determining a cooking zone temperature setpoint based on user input. The method includes directing power to at least one heating element of the appliance based on the cooking zone temperature setpoint and detecting a sensor temperature. The method includes calculating an estimated cooking zone temperature based on the detected sensor temperature value. In response to the cooking zone temperature being at least equal to the cooking zone temperature setpoint, the method includes the step of indicating that the cooking zone of the appliance is preheated.

[0007] In another exemplary aspect of the present disclosure, a system is for determining a cooking zone of an appliance is preheated. The system includes a cooking surface that has the cooking zone, and a heating element configured to heat the cooking surface. The system includes a temperature sensor located away from the cooking zone, the temperature sensor is configured to sense a temperature of the cooking surface. The system also includes a controller communicatively coupled with the heating element and the temperature sensor. The controller is configured to determine a cooking zone temperature setpoint based on user input from the user input device and determine a threshold sensor temperature. The controller is configured to direct power to the heating element based on the cooking zone temperature setpoint and determine a sensor temperature. The controller is configured to calculate an estimated cooking zone temperature based on the determined sensor temperature. Based on the sensor temperature, the controller is configured to direct an indicia to indicate that the cooking zone of the appliance is preheated.

[0008] These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.

[0010] FIG. 1 provides a perspective view of a cooktop with a griddle according to example embodiments of the present disclosure.

[0011] FIG. 2 provides another perspective view of the example cooktop of FIG. 1.

[0012] FIG. 3A provides a graph for a first temperature setpoint, illustrating a comparison of a cooking zone temperature, an estimated cooking zone temperature, and a sensor temperature over time, according to example embodiments of the present disclosure.

[0013] FIG. 3B provides a graph for a second temperature setpoint, illustrating a comparison of a cooking zone temperature, an estimated cooking zone temperature, and a sensor temperature over time, according to example embodiments of the present disclosure.

[0014] FIG. 3C provides a graph for a third temperature setpoint, illustrating a comparison of a cooking zone temperature, an estimated cooking zone temperature, and a sensor temperature over time, according to example embodiments of the present disclosure.

[0015] FIG. 4 provides a graph illustrating a temperature difference between a cooking zone and a sensor temperature over sensor temperature according to example embodiments of the present disclosure.

[0016] FIG. 5 provides an example look-up table correlating a cooking zone temperature setpoint to a threshold sensor temperature according to example embodiments of the present disclosure.

[0017] FIG. 6A provides a part of a flow chart that demonstrates an example method of operating the example embodiments of the present disclosure.

[0018] FIG. 6B provides another part of the flow chart that demonstrates an example method of operating the example embodiments of the present disclosure.

[0019] Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention.DETAILED DESCRIPTION

[0020] Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

[0021] As used herein, the terms “first,”“second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms “includes” and “including” are intended to be inclusive in a manner similar to the term “comprising.” Similarly, the term “or” is generally intended to be inclusive (i.e., “A or B” is intended to mean “A or B or both”). In addition, here and throughout the specification and claims, range limitations may be combined and / or interchanged. Such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. The singular forms “a,”“an,” and “the” include plural references unless the context clearly dictates otherwise.

[0022] Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “generally,”“about,”“approximately,” and “substantially,” are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value, or the precision of the methods or machines for constructing or manufacturing the components and / or systems. For example, the approximating language may refer to being within a 10 percent margin, i.e., including values within ten percent greater or less than the stated value. In this regard, for example, when used in the context of an angle or direction, such terms include within ten degrees greater or less than the stated angle or direction, e.g., “generally vertical” includes forming an angle of up to ten degrees in any direction, e.g., clockwise or counterclockwise, with the vertical direction V.

[0023] The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” In addition, references to “an embodiment” or “one embodiment” does not necessarily refer to the same embodiment, although it may. Any implementation described herein as “an embodiment” is not necessarily to be construed as preferred or advantageous over other implementations. Moreover, each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

[0024] FIG. 1 provides a perspective view of a cooking appliance, or a cooktop 100, including a cooking surface 102, and FIG. 2 provides a similar view of the cooktop 100. Cooktop 100 is provided by way of example only and is not intended to limit the present subject matter to the arrangement shown in FIGS. 1 and 2. Thus, the present subject matter may be used with other cooktop 100 and / or cooking surface 102 configurations, e.g., double oven range appliances, or an oven. As illustrated, cooktop 100 generally defines a vertical direction V, a lateral direction L, and a transverse direction T, each of which is mutually perpendicular, such that an orthogonal coordinate system is generally defined.

[0025] The cooking surface 102 may be generally referred to as a griddle. The cooktop 100 may include a plurality of heating elements 116. For the embodiment depicted, cooktop 100 includes five heating elements 116 spaced along the cooktop 100 where two of the five heating elements 116 are positioned vertically underneath the cooking surface 102 or griddle. Heating elements 116 may be electric heating elements. In certain embodiments, the cooktop 100 is a radiant cooktop with resistive heating elements or coils mounted below cooking surface 102. However, in other embodiments, the cooktop 100 includes other suitable shape, configuration, and / or number of heating elements 116, for example, the cooktop 100 may be an open coil cooktop with heating elements 116 also positioned below cooking surface 102. Additionally or alternatively, in other embodiments, the cooktop 100 may include any other suitable type of heating element 116, such as an induction heating element or gas heating elements. Each of the heating elements 116 may be the same type of heating element 116, or the cooktop 100 may include a combination of different types of heating elements 116.

[0026] As mentioned, heating element 116 may be an induction style heating element. Thus, as would be understood by those skilled in the art, cooktop 100 may supply a current to heating element 116 (e.g., such as a Lenz coil). As such, current may pass through heating element 116 to generate a magnetic field. The magnetic field may be a high frequency circulating magnetic field. The magnetic field may be directed towards and through the cooktop 100 to the cooking surface 102 or a cookware item (e.g., a pan). In particular, when the magnetic field penetrates the cooking surface 102, the magnetic field induces a circulating electrical current within the cooking surface 102. The material properties of cooking surface 102 may restrict a flow of the induced electrical current and convert the induced electrical current into heat within the cooking surface 102. As the cooking surface 102 heats up, contents thereon heat up as well. In such a manner, the induction heating element can cook the contents atop the cooking surface 102.

[0027] As shown in FIG. 1, the cooking surface 102, illustrated as a griddle, may be placed on one or more heating elements 116 to heat the cooking surface 102 and cook or heat food items placed atop the cooking surface 102. One or more user input devices 106 may be positioned proximal or near the cooking surface 102 on the cooktop 100. The user input device 106 may take the form of a knob (as illustrated in the example embodiments). Additionally, or alternatively, a display 108 may be positioned near the cooking surface 102. The display 108 may include the user input device 106 via capacitive touch sensors, for example. The user input device 106 may permit a user to make selections for cooking of food items. More specifically, the user input device 106 may permit a user to set a temperature point for the cooking surface 102. Although shown in front of the heating elements 116, the user input device(s) may be positioned in any suitable location.

[0028] The user input devices 106 may include buttons, knobs, and the like, as well as combinations thereof, and / or user input devices 106 may be implemented on a remote user interface device such as a smartphone. As an example, a user may manipulate one or more user input devices 106 to select a temperature and / or a heat or power output for each heating element 116. The selected temperature or heat output of heating element 116 affects the heat transferred to the cooking surface 102 placed on heating element 116. The display 108 may display information regarding cooking operations or inputs from a user regarding the cooking operation. The display 108 may be any suitable display capable of providing visual feedback, such as a liquid crystal display (LCD), a light emitting diode (LED) display, a segmented display, or the like. Additionally or alternatively, display 108 may be a touch display capable of receiving touch inputs from a user. The display 108 is described in greater detail below.

[0029] The cooktop 100 may further include or be in operative communication with a processing device or a controller 112 that may be generally configured to facilitate appliance operation. In this regard, the heating elements 116, the user input devices 106, and the display 108 may be in communication with controller 112 such that controller 112 may receive control inputs from the user input devices 106, may display information using display 108 (described in greater detail below), and may otherwise regulate operation of cooktop 100. For example, signals generated by controller 112 may operate cooktop 100, including any or all system components, subsystems, or interconnected devices, in response to the position of the user input devices 106 and other control commands. The user input devices 106 and other components of the cooktop 100 may be in communication with controller 112 via, for example, one or more signal lines or shared communication busses. In this manner, Input / Output (“I / O”) signals may be routed between controller 112 and various operational components of cooktop 100.

[0030] As used herein, the terms “processing device,”“computing device,”“controller,” or the like may generally refer to any suitable processing device, such as a general or special purpose microprocessor, a microcontroller, an integrated circuit, an application specific integrated circuit (ASIC), a digital signal processor (DSP), a field-programmable gate array (FPGA), a logic device, one or more central processing units (CPUs), a graphics processing units (GPUs), processing units performing other specialized calculations, semiconductor devices, etc. In addition, these “controllers” are not necessarily restricted to a single element but may include any suitable number, type, and configuration of processing devices integrated in any suitable manner to facilitate appliance operation. Alternatively, controller 112 may be constructed without using a microprocessor, e.g., using a combination of discrete analog and / or digital logic circuitry (such as switches, amplifiers, integrators, comparators, flip-flops, AND / OR gates, and the like) to perform control functionality instead of relying upon software.

[0031] Controller 112 may include, or be associated with, a memory device or one or more memory elements or non-transitory computer-readable storage mediums, such as RAM, ROM, EEPROM, EPROM, flash memory devices, magnetic disks, or other suitable memory devices (including combinations thereof). These memory devices may be a separate component from the processor or may be included onboard within the processor. In addition, these memory devices can store information and / or data accessible by the one or more processors, including instructions that can be executed by the one or more processors. It should be appreciated that the instructions can be software written in any suitable programming language or can be implemented in hardware. Additionally, or alternatively, the instructions can be executed logically and / or virtually using separate threads on one or more processors.

[0032] For example, controller 112 may be operable to execute programming instructions or micro-control code associated with an operating cycle of cooktop 100. In this regard, the instructions may be software or any set of instructions that when executed by the processing device, cause the processing device to perform operations, such as running one or more software applications, displaying a user interface, receiving user input, processing user input, etc. Moreover, it should be noted that controller 112 as disclosed herein is capable of and may be operable to perform any methods, method steps, or portions of methods as disclosed herein. For example, in some embodiments, methods disclosed herein may be embodied in programming instructions stored in the memory and executed by controller 112.

[0033] The memory devices may also store data that can be retrieved, manipulated, created, or stored by the one or more processors or portions of controller 112. The data can include, for instance, data to facilitate performance of methods described herein. The data can be stored locally (e.g., on controller 112) in one or more databases and / or may be split up so that the data is stored in multiple locations. In addition, or alternatively, the one or more database(s) can be connected to controller 112 through any suitable network(s), such as through a high bandwidth local area network (LAN) or wide area network (WAN). In this regard, for example, controller 112 may further include a communication module or interface that may be used to communicate with one or more other component(s) of appliance 100, controller 112, an external appliance controller, or any other suitable device, e.g., via any suitable communication lines or network(s) and using any suitable communication protocol. The communication interface can include any suitable components for interfacing with one or more network(s), including for example, transmitters, receivers, ports, controllers, antennas, or other suitable components.

[0034] Cooktop 100 may include a temperature sensor 110. Temperature sensor 110 may be configured to selectively sense a temperature of the cooking surface 102 (e.g., at an edge of the griddle, as illustrated) as it is heated. For instance, temperature sensor 110 may be integrally formed with cooktop 100 (e.g., within the cooking surface 102). In some embodiments, temperature sensor 110 is operably connected to cooktop 100 (e.g., via a port or socket, via a remote connection, etc.). For one example, temperature sensor 110 is provided within the griddle or cooking surface 102 and operably connected to controller 112 during a cooking operation. Temperature sensor 110 may monitor a temperature of the cooking surface 102 at a location where the temperature sensor 110 is located. Accordingly, temperature sensor 110 may deliver signals (e.g., voltage signals) representing the temperature of the cooking surface 102 at the temperature sensor 110 to controller 112. The signals may be sent according to a predetermined frequency (e.g., at predetermined time intervals). Thus, controller 112 may analyze a sensor temperature Tsensor or change of the sensor temperature Tsensor (i.e., delta Tsensor).

[0035] As used herein, “temperature sensor” or the equivalent is intended to refer to any suitable type of temperature measuring system or device positioned at any suitable location for measuring the sensor temperature. Thus, for example, temperature sensor 110 may be any suitable type of temperature sensor 110, such as a thermistor, a thermocouple, a resistance temperature detector, a semiconductor-based integrated circuit temperature sensor, etc. In addition, temperature sensor 110 may be positioned at any suitable location and may output a signal, such as a voltage, to controller 112 that is proportional to or indicative of the sensor temperature being measured. Although exemplary positioning of the temperature sensor is described herein, it should be appreciated that the cooktop 100 may include any other suitable number, type, and position of temperature or other sensors according to alternative embodiments.

[0036] The sensor temperature Tsensor may be close in value to a temperature of a cooking zone 104. Additionally, or alternatively, because heat dissipates in a solid surface, the temperature of the cooking zone 104 may differ from the sensor temperature because, for example, the cooking zone 104 is spaced from the temperature sensor 110. For example, if the heating element 116 is directly underneath the cooking zone 104, the cooking zone 104 may be at a greater temperature than the temperature sensor 110 that is positioned at a side of the cooking surface 102. Additionally, or alternatively, the cooking zone 104 may heat up faster than the temperature sensor 110 before the cooking zone 104 and the temperature sensor 110 both reach about the same temperature. The sensor temperature and how it relates to the cooking zone temperature are described in greater detail below.

[0037] FIGS. 3A through 3C provide three graphs with three different cooking zone temperature setpoints, each graph illustrating an actual temperature of the cooking zone 104, an actual temperature of the temperature sensor 110, an estimated cooking zone temperature TCZ, a cooking zone temperature setpoint TSP, a sensor temperature setpoint, and the sensor temperature Tsensor where preheating of the cooking zone 104 is complete TPCS. The three graphs illustrate the cooktop 100 operating for about four to five minutes, for about seven minutes, and for about fourteen to sixteen minutes while starting from an ambient temperature. Additionally, or alternatively, the cooktop 100 and method for preheating may start from a higher than ambient temperature. Additionally, or alternatively, the cooktop 100 and method for preheating may start from a lower than ambient temperature. The three graphs also illustrate the respective temperatures increasing as time increases. Additionally, or alternatively, the three graphs may illustrate the cooking zone temperature setpoint TSP at about 330 degrees Fahrenheit, about 400 degrees Fahrenheit, and about 500 degrees Fahrenheit.

[0038] With further reference to FIGS. 3A through 3C, the actual temperature of the temperature sensor 110 may be averaged by a simple moving average (SMA) at about every one second, about every five seconds (as illustrated), or about every ten seconds. The actual temperature of the temperature sensor 110 is illustrated as being less than the actual temperature of the cooking zone 104 before the cooking zone 104 is preheated. The cooking zone 104 may be hotter or heat up faster than the temperature sensor 110 because the cooking zone 104 may be closer to the heating element(s) 116. As illustrated in the example embodiments, the temperature sensor 110 is positioned on an edge of the cooking surface 102 while the cooking zone 104 is located generally in a center of the cooking surface 102.

[0039] The cooking surface 102 may be made from a ceramic or metallic material that has intrinsic properties such as a thermal conductivity, a specific heat capacity, and a density. The thermal conductivity of the cooking surface 102 determines how efficiently heat is transferred through the cooking surface 102 (i.e., how much quicker will heat from the heating element 116 reach the cooking zone 104 compared to the temperature sensor 110). The specific heat capacity of the cooking surface 102 also contributes to a difference in temperature between the cooking zone 104 and the temperature sensor 110 before the cooking surface 102 is preheated. The specific heat capacity of the cooking surface 102 determines how much heat energy is required to raise the temperature of the cooking surface 102. The greater the specific heat capacity, the more heat energy required raise the temperature of the cooking surface 102. Further, the density of the cooking surface 102 also contributes to how quickly the cooking surface 102 heats up during preheating. The greater the density, the slower the cooking surface 102 will preheat.

[0040] Additionally, or alternatively, extrinsic properties unrelated to the material of the cooking surface 102 may affect how quickly the cooking surface 102 preheats. For example, a greater surface area of the cooking surface 102 may subject the cooking surface 102 to more ambient air that is cooler and will cool the cooking surface 102. Further, the larger the cooking surface 102 is, the longer preheating will take because there is more mass to preheat. Even further, the greater the distance between the cooking zone 104 and the temperature sensor 110, the greater the discrepancy between their respective temperatures during preheating.

[0041] With even further reference to FIGS. 3A through 3C, the actual temperature of the cooking zone 104 and the estimated cooking zone temperature TCZ are illustrated as both reaching the cooking zone temperature setpoint TSP before the actual temperature of the temperature sensor 110 reaches the sensor setpoint or sensor target. The sensor temperature Tsensor at which the temperature of the cooking zone 104 reaches the cooking zone temperature setpoint TSP may be found by a look-up table similar to the look-up table of FIG. 5. The sensor temperature Tsensor may be equal to the threshold sensor temperature TPCS. For example, the sensor temperature Tsensor may be about 270 degrees Fahrenheit when the cooking zone temperature reaches the cooking zone temperature setpoint TSP of 330 degrees Fahrenheit. Additionally, or alternatively, the sensor temperature Tsensor may be about 340 degrees Fahrenheit when the cooking zone temperature reaches the cooking zone temperature setpoint TSP of 400 degrees Fahrenheit. Additionally, or alternatively, the sensor temperature Tsensor may be about 455 degrees Fahrenheit when the cooking zone temperature reaches the cooking zone temperature setpoint TSP of 500 degrees

[0042] Fahrenheit. Additionally, or alternatively, the threshold sensor temperature TPCS may be found with interpolation or extrapolation operations based on the values in look-up table of FIG. 5. Additionally, or alternatively, there may be a sensor setpoint temperature that the sensor temperature is driven to. The threshold sensor temperature TPCS may be different from the sensor setpoint temperature because the cooking zone 104 may reach the temperature setpoint TSP before the sensor temperature Tsensor reaches the sensor setpoint temperature. For example, the sensor setpoint temperature may be about ten to about fifteen degrees Fahrenheit higher than the threshold sensor temperature TPCS. Additionally, or alternatively, the sensor setpoint temperature may be found with interpolation or extrapolation from empirical studies of the sensor temperature Tsensor and the actual cooking zone temperature, based on the cooking zone setpoint TSP.

[0043] In detail, as mentioned above, temperature sensor 110 may monitor the temperature of the cooking surface 102 over the course of the cooking or heating operation. The heating operation may include a preheating phase and a cooking phase. The preheating phase may be a variable heating preheating phase. For instance, during the preheating phase, heating element 116 may be driven (e.g., powered) at different power levels based, at least in part, on a measured or estimated difference between a temperature of the cooking zone 104 and the cooking zone temperature setpoint TSP. Accordingly, a controlled temperature increase may be exhibited by the cooking surface 102 because the characteristics of the cooking surface 102 are known and fixed by the manufacturer (e.g., geometry, material used, etc.). Thus, the temperature of the cooking surface 102, and specifically the temperature of the cooking zone 104, is predictable and able to be modeled.

[0044] In the preheating phase, and as illustrated in the flow chart of FIGS. 6A and 6B, the controller 112 may determine the cooking zone temperature setpoint TSP based on user input from the user input devices 106, as illustrated by step 202. The temperature setpoint TSP may be directly entered by the user (e.g., 250 degrees F., 300 degrees F., etc.), or determined by the controller 112 based on a different user selection such as cooking mode (e.g., melt, keep warm, simmer, boil, pan frying, sear, etc.), or food item (e.g., fried eggs, hash browns, salmon, spinach, etc.). The controller 112 then may determine the threshold sensor temperature TPCS that indicates the cooking zone 104 is preheated (reached the cooking zone temperature setpoint TSP), as illustrated by step 204. As mentioned above, the controller 112 may reference a look-up table to determine the threshold sensor temperature TPCS. At step 206, the controller 112 may then store the threshold sensor temperature TPCS in the memory. The controller 112 may then direct power to one or more heating elements 116 based on the cooking zone temperature setpoint TSP, as illustrated by step 208.

[0045] The temperature sensor 110 may then detect the sensor temperature Tsensor. The controller 112 may detect the sensor temperature Tsensor based on a signal received from the sensor temperature Tsensor. The controller 112 may store the sensor temperature Tsensor in the memory about every one second, every five seconds, or every ten seconds, as illustrated by step 210. The controller 112 may determine that at least two sensor temperature values Tsensor have been stored, at least five sensor temperature values Tsensor have been stored, or that at least ten sensor temperature values Tsensor have been stored, as illustrated by step 212. The controller may continue to store sensor temperatures until at least two, five, or ten sensor temperatures have been stored. The controller 112 may then determine the SMA based on the two, five, or ten most recently store sensor temperatures Tsensor, as illustrated by step 214. Additionally, or alternatively, the controller 112 may determine a general average, exponential moving average, mean, median, or other approximation besides the SMA.

[0046] As illustrated by the graph of FIG. 4 there may be a first linearization region r1 and a second linearization region r2 bisected by a region transition boundary (RTB). The RTB may be the sensor temperature value Tsensor that is equal to about 190 degrees Fahrenheit. Additionally, or alternatively, the RTB may be the sensor temperature value Tsensor that ranges between about 150 degrees Fahrenheit and about 200 degrees Fahrenheit. The first linearization region r1 demonstrates how the cooking zone temperature relates to the sensor temperature at sensor temperature values less than the RTB. Additionally, or alternatively, the second linearization region r2 demonstrates how the cooking zone temperature relates to the sensor temperature at sensor temperature values equal to or greater than the RTB. The controller 112 may determine the current linearization region based on the SMA of the sensor temperature Tsensor, as illustrated by step 216.

[0047] According to the determined current linearization region, the controller 112 may then calculate a difference between the cooking zone temperature and the sensor temperature Tsensor based on a first equation, where the difference may be used to determine the estimated cooking zone temperature TCZ, as illustrated by step 218. The first equation (e.g., for first linearization region r1) being:Tdeltar⁢1=ar⁢1*Tsensorr⁢1+br⁢1 Tdelta<sub2>r1 < / sub2>is a difference between the cooking zone temperature and the sensor temperature in a first linearization region r1. ar1 is a first polynomial coefficient for the first linearization region r1. Tsensor<sub2>r1 < / sub2>is the sensor temperature in the first linearization region r1. br1 is a second polynomial coefficient in the first linearization region r1.The polynomial coefficients a and b may be found from empirical study of the sensor temperature Tsensor and the actual cooking zone temperature using linear regression analysis. For example, ar1 may be equal to about 0.69. Additionally, or alternatively, br1 may be equal to about −61.5, for example.

[0049] The controller 112 may alternatively calculate a difference between the cooking zone temperature and the sensor temperature Tsensor based on a second equation (e.g., for second linearization region r2), where the difference may be used to determine the estimated cooking zone temperature TCZ, as illustrated by step 218. The second equation being:Tdeltar⁢2=ar⁢2*Tsensorr⁢2+br⁢2 Tdelta<sub2>r1 < / sub2>is a difference between the cooking zone temperature and the sensor temperature in a second linearization region r2. ar2 is the first polynomial coefficient for the second linearization region r2. Tsensor<sub2>r2 < / sub2>is the sensor temperature in the second linearization region r2. br2 is the second polynomial coefficient in the second linearization region r2.The polynomial coefficients a and b may be found from empirical study of the sensor temperature Tsensor and the actual cooking zone temperature using linear regression analysis. For example only, ar2 may be equal to about −0.076. Additionally, or alternatively, br2 may be equal to about 81.5, for example.

[0051] Additionally, or alternatively, the controller 112 may calculate the estimated cooking zone temperature TCZ with a third equation, as illustrated by step 218:TCZri=Tsensorri+TdeltariTCZri is the estimated cooking zone temperature in at least one of the first linearization region r1 or the second linearization region r2. Tsensor<sub2>ri < / sub2>is the sensor temperature in at least one of the first linearization region r1 or the second linearization region r2. Tdelta<sub2>ri < / sub2>is a difference between the cooking zone temperature and the sensor temperature in at least one of the first linearization region r1 or second linearization region r2 from at least one of the first equation and the second equation.Additionally, or alternatively, the controller 112 may calculate the estimated cooking zone temperature TCZ with a fourth equation, as illustrated by step 218:TCZ=c+d*Tsensor+e*(Tsensor)2+f*(Tsensor)3c, d, e, and f are polynomial coefficients that may be determined by a regression analysis from empirical study of the sensor temperature Tsensor and the actual cooking zone temperature. For example only, c may be about −108.1, d may be about 2.564, e may be about −0.004535, and f may be about 0.000004. In the context of this patent application, it is understood by one of ordinary skill in the art that the equation utilized is not limited to the specific form presented herein; rather, it may encompass polynomials of various orders or other equation types including, but not limited to, exponential, logarithmic, or trigonometric functions, depending on the requirements of the specific application.The controller 112 may then determine whether the estimated cooking zone temperature TCZ is less than a minimum temperature to be indicated TMIN, as illustrated by step 220. The minimum temperature to be indicated TMIN may be set by the user, the manufacturer, or a distributor of the appliance. The minimum temperature the be indicated TMIN may be indicated via the display 108 or via an auditory device 114 communicatively coupled with the controller 112. The auditory device 114 may be, for example, a speaker. The minimum temperature to be indicated TMIN may be, for example only, about 100 degrees Fahrenheit.In response to the estimated cooking zone temperature TCZ being less than the minimum temperature to be indicated TMIN, the controller may direct the display 108 and / or the auditory device 114 to indicate the TMIN, as illustrated by step 222. In response to the estimated cooking zone temperature TCZ being equal to or greater than the TMIN, the controller 112 may determine whether the estimated cooking zone temperature TCZ is greater than a maximum temperature to be indicated TMAX, as illustrated by step 224. TMAX may be equal to the cooking zone temperature setpoint TSP. In response to the estimated cooking zone temperature TCZ being greater than TMAX, the controller 112 may direct the display 108 and / or the auditory device 114 to constantly, or periodically, indicate TMAX, as illustrated by step 226. Additionally, or alternatively, the display 108 may display the word “cooking” or “preheated.” In response to the estimated cooking zone temperature TCZ being equal to or less than TMAX, the controller may round the estimated cooking zone temperature TCZ to the nearest number divisible by five, for example, as illustrated by step 228.

[0055] The controller 112 may then determine whether the rounded estimated cooking zone temperature TCZ is less than or equal to the currently displayed cooking zone temperature, as illustrated by step 230. In response to the affirmative, the controller 112 may leave the currently indicated cooking zone temperature at display 108 and / or auditory device 114 unchanged, as illustrated by step 232. In response to the negative, the controller 112 may direct the display 108 and / or auditory device 114 to indicate the estimated current cooking zone temperature TCZ that is rounded, as illustrated by step 234.

[0056] The controller 112 may then detect or determine the sensor temperature Tsensor based on a signal received from the sensor temperature 110. The controller 112 may then store the two, five, or ten most recent sensor temperature values Tsensor and delete the previous sensor temperature values beyond the two, five, or ten most recent, as illustrated by step 236. Step 238 is the same as step 214. Step 240 allows the method to repeat the process at step 216 if the controller determines the average of the sensor temperature Tsensor is not greater than or equal to the threshold sensor temperature TPCS. If the sensor temperature Tsensor is greater than or equal to the threshold sensor temperature TPCS, the controller 112 may direct the display 108 and / or the auditory device 114 to constantly, or periodically, indicate that preheating is complete, as illustrated by step 242. For example, the display 108 may display the word “cooking” or “preheated.” The controller 112 may additionally or alternatively direct the display and / or auditory device to indicate the cooking zone temperature setpoint TSP, as illustrated in FIG. 2. For example, the display 108 may display the word “cooking” and the number “400” degrees Fahrenheit.

[0057] Advantageously, the presently described cooking appliance or cooktop, allows for a user to be informed of whether a cooking surface, for example a griddle, is preheated. The presently described cooktop further allows for a user to know the estimated cooking zone temperature periodically before preheating ends. This allows a user to better gauge when a food item should be placed onto the cooking surface. Ultimately, the cooktop saves the user time and effort and makes the cooking experience more enjoyable, by providing a more predictable preheating process and facilitating multitasking. Additionally, an accurate cooking zone temperature estimation may prevent food items from being wasted from improper cooking.

[0058] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. A method of determining a cooking zone of an appliance is preheated, the method comprising:determining a cooking zone temperature setpoint based on user input;directing power to at least one heating element of the appliance based on the cooking zone temperature setpoint;detecting a sensor temperature;calculating an estimated cooking zone temperature based on the sensor temperature; andbased on the sensor temperature, indicating that the cooking zone of the appliance is preheated.

2. The method of claim 1, further comprising a step of determining a threshold sensor temperature indicative of a preheating of the cooking zone being complete based on the cooking zone temperature setpoint.

3. The method of claim 2, wherein about five most recent sensor temperature values are used to determine a simple moving average of the sensor temperature.

4. The method of claim 1 further comprising the step of indicating the estimated cooking zone temperature.

5. The method of claim 1, further includes the step of calculating a difference between the cooking zone temperature and the sensor temperature based on a first equation:Tdeltar⁢1=ar⁢1*Tsensorr⁢1+br⁢1wherein Tdelta<sub2>r1 < / sub2>is a difference between the cooking zone temperature and the sensor temperature in a first linearization region;wherein ar1 is a first polynomial coefficient for the first linearization region;wherein Tsensor<sub2>r1 < / sub2>is the sensor temperature in the first linearization region; andwherein br1 is a second polynomial coefficient in the first linearization region.

6. The method of claim 5 further includes the step of calculating a difference between the cooking zone temperature and the sensor temperature based on a second equation:Tdeltar⁢2=ar⁢2*Tsensorr⁢2+br⁢2 wherein Tdelta<sub2>r2 < / sub2>is the difference between the cooking zone temperature and the sensor temperature in a second linearization region;wherein ar2 is the first polynomial coefficient for the second linearization region;wherein Tsensor<sub2>r2 < / sub2>is the sensor temperature in the second linearization region; andwherein br2 is the second polynomial coefficient in the second linearization region.

7. The method of claim 6, wherein the step of calculating an estimated cooking zone temperature is based on a third equation:TCZri=Tsensorri+Tdeltariwherein TCZ<sub2>ri < / sub2>is an estimated cooking zone temperature in at least one of the first linearization region or the second linearization region.

8. The method of claim 7, wherein a linearization region chosen between the first linearization region and the second linearization is determined by comparing the sensor temperature to a region transition boundary, wherein the first linearization region corresponds to the sensor temperature being less than the region transition boundary, and wherein the second linearization region corresponds to the sensor temperature being equal to or greater than the region transition boundary.

9. The method of claim 1, wherein the step of calculating the estimated cooking zone temperature is based on a fourth equation:TCZ=c+d*Tsensor+e*(Tsensor)2+f*(Tsensor)3wherein c, d, e, and f are polynomial coefficients determined by a regression analysis;wherein TCZ is the estimated cooking zone temperature; andwherein Tsensor is the sensor temperature.

10. The method of claim 2, wherein the step of determining the threshold sensor temperature is based on a look-up table correlating the threshold sensor temperature to the cooking zone temperature setpoint.

11. A system for determining a cooking zone of an appliance is preheated, the system comprising:a cooking surface having a cooking zone;a heating element configured to heat the cooking surface;a temperature sensor located away from the cooking zone, the temperature sensor is configured to sense a temperature of the cooking surface;a controller communicatively coupled with the heating element and the temperature sensor, wherein the controller is configured to:determine a cooking zone temperature setpoint;determine a threshold sensor temperature indicative of a preheating of the cooking zone being complete based on the cooking zone temperature setpoint;direct power to the heating element based on the cooking zone temperature setpoint;determine a sensor temperature; andcalculate an estimated cooking zone temperature based on the sensor temperature; andbased on the sensor temperature, direct an indicia to indicate that the cooking zone of the appliance is preheated.

12. The system of claim 11, wherein the controller stores the sensor temperature at least twice to determine a simple moving average of the sensor temperature, wherein at least two most recent sensor temperatures are used to determine the simple moving average of the sensor temperature.

13. The system of claim 11, wherein the controller stores the sensor temperature about every one second, about every five seconds, or about every ten seconds.

14. The system of claim 11, wherein the controller is further configured to calculate a difference between the cooking zone temperature and the sensor temperature based on a first equation:Tdeltar⁢1=ar⁢1*Tsensorr⁢1+br⁢1wherein Tdelta<sub2>r1 < / sub2>is a difference between the cooking zone temperature and the sensor temperature in a first linearization region;wherein ar1 is a first polynomial coefficient for the first linearization region;wherein Tsensor<sub2>r1 < / sub2>is the sensor temperature in the first linearization region; andwherein br1 is a second polynomial coefficient in the first linearization region.

15. The system of claim 12, wherein the controller is further configured to calculate a difference between the cooking zone temperature and the sensor temperature based on a second equation:Tdeltar⁢2=ar⁢2*Tsensorr⁢2+br⁢2 wherein Tdelta<sub2>r2 < / sub2>is the difference between the cooking zone temperature and the sensor temperature in a second linearization region;wherein ar2 is the first polynomial coefficient for the second linearization region;wherein Tsensor<sub2>r2 < / sub2>is the sensor temperature in the second linearization region; andwherein br2 is the second polynomial coefficient in the second linearization region.

16. The system of claim 15, wherein the controller is further configured to calculate an estimated cooking zone temperature is based on a third equation:TCZri=Tsensorri+Tdeltariwherein TCZ<sub2>ri < / sub2>is an estimated cooking zone temperature in at least one of the first linearization region or the second linearization region.

17. The system of claim 16, wherein a linearization region chosen between the first linearization region and the second linearization is determined by comparing the sensor temperature to a region transition boundary, wherein the first linearization region corresponds to the sensor temperature being less than the region transition boundary, and wherein the second linearization region corresponds to the sensor temperature being equal to or greater than the region transition boundary.

18. The system of claim 11, wherein the controller is further configured to calculate the estimated cooking zone temperature based on a fourth equation:TCZ=c+d*Tsensor+e*(Tsensor)2+f*(Tsensor)3wherein c, d, e, and f are polynomial coefficients determined by a regression analysis;wherein TCZ is the estimated cooking zone temperature; andwherein Tsensor is the sensor temperature.

19. The system of claim 1, wherein the appliance further includes an auditory device communicatively coupled with the controller, wherein the controller activates the auditory device to provide a sound indicating the cooking zone is preheated.

20. The system of claim 1 further comprising a display, wherein the controller activates the display to display the estimated cooking zone temperature.

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