Patent Application
20210172602
The present subject matter relates generally to cooktop appliances with gas burner assemblies, such as gas range appliances or gas stove appliances.
Certain cooktop appliances include gas burners for heating cooking utensils on the cooktop appliances. Some users prefer gas burners over electric heating elements due to the adjustability of gas burners. In particular, a gas burner's control valve can provide more heat outputs compared to the discrete number of output settings available for electric heating elements. However, precisely heating a cooking utensil with a gas burner can be difficult. For example, a user may have to constantly monitor the cooking utensil and tweak the control valve to maintain a particular temperature in the cooking utensil, and such monitoring and adjustment can be tedious.
Accordingly, a cooktop appliance with features for operating a gas burner to maintain a particular temperature in a cooking utensil would be useful.
Aspects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention.
In one example embodiment, a method of operating a cooktop appliance is provided. The cooktop appliance includes a gas burner. The method includes receiving a user-determined set temperature from a user interface of the cooktop appliance and activating the gas burner. The method also includes receiving a precision mode initiation signal from the user interface. The method further includes receiving a temperature measurement from a temperature sensor configured to measure a temperature at a utensil heated by the gas burner. The user-determined set temperature and the temperature measurement are input into a closed-loop control algorithm. The closed-loop control algorithm produces an output based on the user-determined set temperature and the temperature measurement. The method also includes comparing the output of the closed-loop control algorithm to a threshold power level. When the output of the closed-loop control algorithm is less than the threshold power level, a first control valve to the gas burner is closed.
In another example embodiment, a method of operating a cooktop appliance is provided. The cooktop appliance includes a gas burner. The method includes receiving a user-determined set temperature from a user interface of the cooktop appliance and activating the gas burner. The method also includes receiving a precision mode initiation signal from the user interface. The method further includes receiving a temperature measurement from a temperature sensor configured to measure a temperature at a utensil heated by the gas burner. The user-determined set temperature and the temperature measurement are input into a closed-loop control algorithm. The closed-loop control algorithm produces an output based on the user-determined set temperature and the temperature measurement. The method also includes comparing the output of the closed-loop control algorithm to a threshold power level. When the output of the closed-loop control algorithm is less than the threshold power level, a first control valve to the gas burner is closed.
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.
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.
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 or spirit 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.
As used herein, terms of approximation, such as “generally,” or “about” include values within ten percent greater or less than the stated value. 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. For example, “generally vertical” includes directions within ten degrees of vertical in any direction, e.g., clockwise or counter-clockwise.
Upper and lower cooking chambers 120 and 122 are configured for the receipt of one or more food items to be cooked. Range appliance 100 includes an upper door 124 and a lower door 126 rotatably attached to cabinet 110 in order to permit selective access to upper cooking chamber 120 and lower cooking chamber 122, respectively. Handles 128 are mounted to upper and lower doors 124 and 126 to assist a user with opening and closing doors 124 and 126 in order to access cooking chambers 120 and 122. As an example, a user can pull on handle 128 mounted to upper door 124 to open or close upper door 124 and access upper cooking chamber 120. Glass window panes 130 provide for viewing the contents of upper and lower cooking chambers 120 and 122 when doors 124 and 126 are closed and also assist with insulating upper and lower cooking chambers 120 and 122. Heating elements (not shown), such as electric resistance heating elements, gas burners, microwave heating elements, halogen heating elements, or suitable combinations thereof, are positioned within upper cooking chamber 120 and lower cooking chamber 122 for heating upper cooking chamber 120 and lower cooking chamber 122.
Range appliance 100 also includes a cooktop 140. Cooktop 140 is positioned at or adjacent a top portion of cabinet 110. Thus, cooktop 140 is positioned above upper and lower cooking chambers 120 and 122. Cooktop 140 includes a top panel 142. By way of example, top panel 142 may be constructed of glass, ceramics, enameled steel, and combinations thereof.
For range appliance 100, a utensil holding food and/or cooking liquids (e.g., oil, water, etc.) may be placed onto grates 152 at a location of any of burner assemblies 144, 146, 148, 150. Burner assemblies 144, 146, 148, 150 provide thermal energy to cooking utensils on grates 152. As shown in
A user interface panel 154 is located within convenient reach of a user of the range appliance 100. For this example embodiment, user interface panel 154 includes knobs 156 that are each associated with one of burner assemblies 144, 146, 148, 150 and griddle burner 160. Knobs 156 allow the user to activate each burner assembly and determine the amount of heat input provided by each burner assembly 144, 146, 148, 150 and griddle burner 160 to a cooking utensil located thereon. The user interface panel 154 may also include one or more inputs 157, such as buttons or a touch pad, for selecting or adjusting operation of the range appliance 100, such as for selecting or initiating a precision cooking mode, as will be described in more detail below. User interface panel 154 may also be provided with one or more graphical display devices 155 that deliver certain information to the user such as e.g., whether a particular burner assembly is activated and/or the temperature at which the burner assembly is set.
Although shown with knobs 156, it should be understood that knobs 156 and the configuration of range appliance 100 shown in
The control valves 220 and 230 are coupled to supply line 210 in series and are configured for regulating the flow of gaseous fuel through supply line 210 to burner assembly 144. In particular, the control valves 220 and 230 may be operatively and/or communicatively coupled to one of knobs 156, e.g., via one or more controllers 240 and/or 242, as illustrated in
For example, as illustrated in
In precision cooking mode, control valves 220 and 230 may be automatically adjusted to regulate the flow of gaseous fuel to burner assembly 144. In some embodiments, range appliance 100 may include a controller 240 and range controls 242 that collectively regulate various components of range appliance 100, e.g., as illustrated in
Controller(s) 240 and/or 242 include memory and one or more processing devices such as microprocessors, CPUs or the like, such as general or special purpose microprocessors operable to execute programming instructions or micro-control code associated with operation of range appliance 100. The memory can be non-transitory and represent random access memory (“RAM”) such as dynamic random access memory (“DRAM”), or read only memory such as ROM or FLASH. The processor executes programming instructions stored in the memory. The memory can be a separate component from the processor or can be included onboard within the processor. The memory can store information accessible by the processor(s), including instructions that can be executed by the processor(s). For example, the instructions can be software or any set of instructions that when executed by the processor(s), cause the processor(s) to perform operations. For the embodiment depicted, the instructions may include a software package configured to operate the system to, e.g., execute the exemplary methods described below. Alternatively, controller(s) 240 and/or 242 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 gates, and the like) to perform control functionality instead of relying upon software.
Controller 240 is also in communication with temperature sensor 250, e.g., via the range controls 242 in the illustrated example embodiments, although it should be understood that the range controls 242 may also be integrated with the controller 240 in other embodiments. Temperature sensor 250 is separate from burner assembly 144, and temperature sensor 250 is configured to measure a temperature at a utensil heated by burner assembly 144. Thus, temperature sensor 250 may be a thermistor or thermocouple positioned on and/or disposed within a utensil positioned above burner assembly 144 on cooktop 140. Range controls 242 receive temperature measurements from temperature sensor 250. For example, range controls 242 and temperature sensor 250 may each include a wireless transmitter/receiver such that controller 240 and temperature sensor 250 communicate with each other wirelessly, e.g., via a Bluetooth® or Wi-Fi® connection. In certain example embodiments, temperature sensor 250 is a separate component mountable to the utensil heated by burner assembly 144. In alternative example embodiments, temperature sensor 250 may be integrated within the utensil heated by burner assembly 144. For example, the temperature sensor 250 may be disposed within the utensil in that the temperature sensor 250 is positioned within an internal cooking volume defined in the utensil, or the temperature sensor 250 may be embedded in a wall of the cooking utensil.
In the example embodiment depicted in
Combustion may be initiated in the associated burner assembly 144 by an ignition module 244 which will call for a spark at an igniter of the burner assembly 144. As illustrated in
According to various embodiments of the present disclosure, the range appliance 100 may be configured for a precision cooking mode and/or methods of operating the range appliance 100 may include precision cooking mode. Precision cooking mode generally includes a closed-loop control algorithm used to automatically (e.g., without user input such as adjusting the knobs 156) adjust the flow of gas to one or more of the burner assemblies 144, 146, 148, 150 and griddle burner 160. Utilizing temperature measurements from temperature sensor 250 and/or range controls 242, controller 240 may adjust the first and second control valves 220 and 230 (which may include, e.g., adjusting a position of the stepper motor 231) and regulate the flow of gaseous fuel to, e.g., burner assembly 144. In some embodiments, the precision cooking mode operation may be performed at least in part by a closed loop control algorithm carried out by the range controls 242, e.g., the range controls 242 may send and receive signals to and from the controller 240, whereby the range controls 242 receives the user-determined set temperature and a temperature measurement from the temperature sensor 250, then determines an output of the closed-loop control algorithm, such as a requested power level of the burner, based on the user-determined set temperature and the temperature measurement. The range controls 242 may then transmit the output, e.g., requested power level, to the controller 240. In additional embodiments, the closed loop control system 242 may be incorporated onboard and/or integrated into the controller 240. In some embodiments, the user may turn on the closed loop controls by initiating precision cooking mode, such as by pressing a corresponding one of the inputs 157 on the user interface 154. Other inputs 157 of the user interface 154 may be used to input a user-defined set temperature or target temperature for the cooking operation.
When the precision cooking mode is activated, controller 240 and/or range controls 242 receives the temperature measurements from temperature sensor 250 and compares the temperature measurements to a target temperature, e.g., the user-defined set temperature. In order to reduce a difference between the temperature measurements from temperature sensor 250 and the target temperature, controller 240 adjusts the flow of gaseous fuel to burner assembly 144 with control valves 220 and 230, for example, such adjustment may be according to a requested power level which is output from the closed-loop control algorithm performed by the range controls 242. In particular, controller 240 may adjust control valves 220 and 230 to decrease the flow of gaseous fuel to burner assembly 144 when the temperature measurements from temperature sensor 250 are greater than the set temperature. Conversely, controller 240 may adjust control valves 220 and 230 to increase the flow of gaseous fuel to burner assembly 144 when the temperature measurements from temperature sensor 250 are less than the set temperature. Thus, the heat output provided by burner assembly 144 may be regulated by the closed loop control system, e.g., without additional user input and/or monitoring.
A user may establish the set temperature via a user interface 260, e.g., the user interface 260 may include inputs 157 and a display 155, as in the illustrated example embodiment. Controller 240 and/or range controls 242 is or are in communication with user interface 260 and configured to receive the user-determined set temperature from user interface 260. User interface 260 may correspond to user interface panel 154 in certain example embodiments. Thus, the user may, for example, utilize keys 157 on user interface panel 154 to establish the set temperature. In such example embodiments, user interface 260 is positioned on top panel 142 and may be in communication with controller(s) 240 and/or 242 via a wiring harness. As another example, user interface 260 may correspond to an application on a smartphone or other device, and the user may utilize the application to establish the set temperature. In such example embodiments, user interface 260 may be in wireless communication with controller(s) 240 and/or 242, e.g., via a Bluetooth® or Wi-Fi® connection.
Turning now to
After initializing closed-loop cooking at step 402, the method 400 may include inputting the user-determined set temperature and the temperature measurement into a closed-loop control algorithm, for example, the closed-loop control algorithm may be a PID (proportional-integral-derivative) algorithm. The closed-loop control algorithm may be carried out by, for example, the range controls 242. The closed-loop control algorithm then produces an output based on the user-determined set temperature and the temperature measurement. The output may be a requested power level. The method 400 may include a step 404 of comparing the output of the closed-loop control algorithm, e.g., the requested power level, to a threshold power level. For example, as illustrated in
When the requested power level is greater than or equal to the threshold power level at step 404, the method 400 may proceed to step 430, where the control valve or valves is or are adjusted according to the requested power level. For example, in some embodiments such as the examples illustrated in
When the requested power level is less than the threshold power level at step 404, the method 400 may proceed to step 405 and/or step 406, as illustrated in
After turning the burner OFF, e.g., by closing the first control valve 220 (e.g., solenoid valve 220 in some embodiments) and/or disabling ignition, the method 400 may include a step 408 of starting a burner OFF time count. The burner OFF time count may be used to provide a minimum OFF time X and/or a maximum OFF time Z. In various embodiments, the minimum OFF time X may be between about ten seconds and about one minute, such as between about fifteen seconds and about forty-five seconds, such as about twenty seconds. In various embodiments, the maximum OFF time Z may be less than or equal to about two minutes, such as about ninety seconds, or about one minute, among other examples. In embodiments where the minimum OFF time X and the maximum OFF time Z are both included, the maximum OFF time Z is greater than the minimum OFF time X.
For example, the method 400 may include a step 410 of comparing the burner OFF time count to the minimum OFF time X. When the burner OFF time count is not greater than, i.e., is less than or equal to, the minimum OFF time X (e.g., when the result at 410 in
When the burner OFF time count is greater than the minimum OFF time X, the method 400 may then include an additional comparing step 414 of comparing the output of the closed-loop control algorithm to the threshold power level.
When the closed-loop control output is still not greater than the power level threshold after allowing the minimum OFF time to elapse, e.g., when the burner OFF time count is greater than the minimum OFF time X and the requested power level is less than or equal to the power level threshold, the method 400 may continue to a step 416 of determining whether the burner OFF time count is greater than the maximum OFF time Z (i.e., when the requested power level is not greater than the power level threshold, as indicated in
When the output of the closed-loop control algorithm, e.g., the requested power level, is greater than the threshold power level after the minimum OFF time X at step 414, the method 400 may then continue to step 418 and step 417. The method 400 may also continue to step 418 and step 417 when the burner OFF time count is greater than the maximum OFF time Z.
For example, in embodiments where the method 400 includes deactivating the re-ignition module of the cooktop appliance when the output of the closed-loop control algorithm is less than the threshold power level, e.g., by engaging a normally-closed relay at step 405, the method 400 may also include a step 417 of re-activating the re-ignition module, e.g., by disengaging the normally-closed relay such that a call for spark may be initiated by the re-ignition module.
In some embodiments, method 400 may include opening the first control valve, e.g., solenoid valve as in the illustrated embodiments, at step 418, e.g., as illustrated in
After opening the solenoid valve at step 418 and, in at least some embodiments, re-activating the re-ignition module at step 417, the method 400 may also include starting a burner ON time count, e.g., as illustrated at step 420 in
While the burner is ON, e.g., while the control valves are open and thereby fuel is supplied to the burner and the ignition module is activated to provide ignition, and after starting the burner ON time count, the method 400 may compare the output of the closed-loop control algorithm to the threshold power level, e.g., as illustrated at step 422 in
As long as the requested power level is greater than the power level threshold, e.g., when the determination at step 422 is positive (“Yes” as indicated in
When the requested power level is not greater than the power level threshold at step 422 but the burner ON time count is not greater than the minimum ON time Y at step 428, then the method 400 returns to step 422 and iterates the successive steps 422, 424, and 428 until step 428 leads to a “Yes,” e.g., until the burner ON time is greater than the minimum burner ON time Y. Thus, the method may include and/or the cooktop appliance may be configured to operate the burner at a minimum level for at least the minimum ON time even while the output of the closed-loop algorithm is calling for a power level less than the minimum level.
After the minimum ON time Y has elapsed, e.g., as may be seen by following the “Yes” branch from 428 in
As may be seen from the above, the present disclosure provides a precision cooking mode, e.g., a closed-loop control system for operation of a cooktop appliance, which includes increased flexibility of operation, including a closed-loop controlled simmer setting, and cooktop appliances configured to operate according to such methods. For example, the present disclosure may provide a closed-loop cooking mode wherein excessive sparking of the igniter and/or excessive cycling (turning ON and OFF) of the burner may be avoided by use of minimum OFF time, maximum OFF time, and/or minimum ON time.
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.
