Patent Application
20220178538
Cooking appliances such as cooktops, ovens and ranges may be powered by various types of burners or cooking elements, with electrical heating elements and gas burners being among the most common. In particular, gas burners generally use as an energy source a combustible gas such as natural gas or liquified petroleum (LP) gas (also referred to as propane), and generate heat by combusting and burning the gas. The output levels of gas burners are generally controlled by valves, which regulate gas flow to the gas burners, and which are coupled either mechanically or electronically to associated user controls, e.g., knobs, sliders, or the like. Gas burners also generally require some manner of igniting the burners. For gas cooktop burners, for example, spark igniters are commonly used, while for gas oven burners, hot surface igniters are also commonly used. In addition, some cooking appliances incorporate automatic ignition modules that include flame sensors and that are capable of automatically re-igniting a gas burner in response to a detected flame loss by a flame sensor.
With many manual gas cooktops, for example, a control knob is typically mechanically coupled to a gas valve, and a switch is used to activate a spark igniter when the control knob is in a particular range of rotational positions or when the control knob is pressed inwardly. The gas valve is designed so that, from an off position, the gas valve remains closed for a portion of the rotation but then opens relatively quickly to a maximum flow position at about a one quarter turn (90 degrees) from the off position, which corresponds to the maximum output level for the gas burner. Turning the knob further through the next half turn gradually reduces the flow rate until a minimum flow position is reached at about a three quarter turn (270 degrees) from the off position, whereby further turning is restricted
Many manual gas cooktops are specifically designed so that the igniter turns on before gas begins flowing through the valve to prevent the flow of unburned gas, and then turns off slightly before the maximum flow position is reached. The igniter, if implemented as a spark igniter, generally produces a series of sparks at repeatable intervals, which produces a distinctive clicking sound that lets the user know that the igniter is active. For hot surface igniters, the problem is more acute, since these igniters are more commonly used for ovens and emit no sound, so a user would generally not be aware when a hot surface igniter was active.
In addition, even when a user is able to see and/or hear the sparks generated by an igniter, a user still may have difficulty properly igniting the burner because the gas flow is insufficient for ignition. Since the igniter is turned on prior to gas flow, the fact that the igniter is on is not an indication that the valve is in a position to output sufficient gas flow to ignite the burner. As such, a user is often required to turn the knob back and forth to search out the proper position where the burner will ignite.
Automatic ignition systems also suffer from similar issues, as a user may not always be aware when a flame has been lost and re-ignition has occurred. While many automatic ignition systems incorporate functionality to shut off gas flow if re-ignition cannot be attained, where re-ignition can be successfully attained, a user may not be aware that the re-ignition occurred, so the root cause of that flame loss (e.g., a draft, an open door, etc.) may cause re-ignition to be needed multiple times, whereas if the user was aware of the re-ignition the user could potentially address that root cause and prevent further flame loss in the first place.
The herein-described embodiments address these and other problems associated with the art by utilizing a control circuit in a gas cooking appliance to generate an audible and/or visual indication to a user when a user control for a gas burner is in a position within which an igniter is active and a gas valve is supplying sufficient gas flow to the gas burner to support ignition and thereby assist a user in properly positioning the user control during ignition of the burner.
Therefore, consistent with one aspect of the invention, a cooking appliance may include a gas burner, an igniter disposed adjacent to the gas burner to ignite the gas burner, a gas valve configured to regulate gas flow to the gas burner, a burner control coupled to the gas valve to vary the gas flow to the gas burner, the burner control movable between first, second, third and fourth ranges of positions, where in the first and fourth ranges the igniter is inactive and in the second and third ranges of positions the igniter is active, and in the first and second ranges the gas valve supplies insufficient gas flow to the gas burner to support ignition and in the third and fourth ranges the gas valve supplies sufficient gas flow to the gas burner to support ignition, and a control circuit configured to generate an indication to a user when the burner control is positioned within the third range of positions to assist the user in properly positioning the burner control during ignition of the burner.
In some embodiments, the control circuit is configured to generate the indication by generating an audible indication. Further, in some embodiments, the control circuit includes a speaker, and the audible indication is generated by the speaker. In addition, in some embodiments, the control circuit is configured to generate the indication by generating a visual indication. Further, in some embodiments, the burner control includes a rotary control actuator and an illumination source, and the control circuit is configured to generate the indication using the illumination source.
Moreover, in some embodiments, the illumination source is a light ring that circumscribes the rotary control actuator. Further, in some embodiments, the control circuit is configured to generate the indication by illuminating the illumination source in a first color, and to generate a second indication when the burner control is positioned within the fourth range of positions by illuminating the illumination source in a second color. In some embodiments, the control circuit is configured to generate the indication by illuminating the illumination source using a first illumination pattern, and to generate a second indication when the burner control is positioned within the fourth range of positions by illuminating the illumination source using a second illumination pattern.
Moreover, in some embodiments, the control circuit is further configured to generate a second indication to the user when a duration the burner control has remained within either of the second or third ranges of positions meets an alert criterion. Some embodiments may further include a flame detector positioned to sense a flame emitted by the gas burner, and the control circuit is further configured to generate a second indication to the user when a duration the burner control has remained within any of the second, third or fourth ranges of positions while the flame detector fails to detect a flame meets an alert criterion. In addition, in some embodiments, the control circuit is further configured to disable a self-clean mode for the cooking appliance when the burner control is within any of the second, third or fourth ranges of positions.
Also, in some embodiments, the gas valve includes a mechanical gas valve, and the burner control is mechanically coupled to the mechanical gas valve to vary the gas flow to the gas burner. Moreover, in some embodiments, the burner control includes a rotary control actuator, a first switch coupled to the igniter and configured to activate the igniter whenever the burner control is in the second or third ranges of positions, and a second switch configured to cause the control circuit to generate the indication whenever the burner control is in the third range of positions.
In some embodiments, the control circuit is configured to generate the indication in response to actuation of both the first and second switches, the rotary control actuator includes one or more cam lobes that oppose the first and second switches, and the one or more cam lobes are configured to actuate the first switch when the rotary control actuator is positioned between about 20 degrees and about 85 degrees from an off position for the burner control, and to actuate the second switch when the rotary control actuator is positioned at or beyond about 65 degrees from the off position for the burner control.
Consistent with another aspect of the invention, a cooking appliance may include a gas burner, an igniter disposed adjacent to the gas burner to ignite the gas burner, a mechanical gas valve configured to regulate gas flow to the gas burner, a burner control mechanically coupled to the gas valve to vary the gas flow to the gas burner, the burner control including a rotary control actuator that is rotatable from an off position, and first and second switches positioned adjacent thereto, the rotary control actuator including one or more cam lobes configured to engage the first and second switches to actuate the first and second switches within respective first and second ranges of rotational positions of the rotary control actuator, where a starting position of the second range of rotational positions has a greater rotational offset from the off position than a start position of the first range of rotational positions, and a control circuit configured to activate the igniter in response to actuation of the first switch and to generate an indication to a user in response to actuation of the second switch.
Further, in some embodiments, the first and second ranges partially overlap, and when rotary control actuator is positioned within a non-overlapping portion of the first range of rotational positions, the mechanical gas valve supplies insufficient gas flow to the gas burner for ignition and when the rotary control actuator is positioned within an overlapping portion of the first range of rotational positions, the mechanical gas valve supplies sufficient gas flow to the gas burner for ignition, and the indication assists the user in properly positioning the rotary control actuator during ignition of the burner. Also, in some embodiments, the control circuit is configured to disable a self-clean mode for the cooking response in response to actuation of either of the first and second switches. Further, in some embodiments, the control circuit is configured to generate a second indication to the user when a duration the first switch has been actuated meets an alert criterion. In addition, some embodiments may also include a flame detector positioned to sense a flame emitted by the gas burner, and the control circuit is further configured to generate a second indication to the user when a duration either the first switch or the second switch has remained actuated while the flame detector fails to detect a flame meets an alert criterion.
Consistent with another aspect of the invention, a method of igniting a gas burner of a cooking appliance controlled by a burner control coupled to a gas valve that varies gas flow to the gas burner may include, in response to user movement of the burner control away from an off position and to a first position having a first offset from the off position, activating an igniter disposed adjacent to the gas burner, and in response to user movement of the burner control beyond the first position and to a second position having a second offset from the off position that is greater than the first offset, generating an indication to a user to assist the user in properly positioning the burner control during ignition of the burner, where when the burner control is in the first position, the gas valve supplies insufficient gas flow to the gas burner to support ignition and when the burner control is in the second position, the gas valve supplies sufficient gas flow to the gas burner to support ignition, and where the indication is inactive when the burner control is positioned in the first position.
These and other advantages and features, which characterize the invention, are set forth in the claims annexed hereto and forming a further part hereof. However, for a better understanding of the invention, and of the advantages and objectives attained through its use, reference should be made to the Drawings, and to the accompanying descriptive matter, in which there is described example embodiments of the invention. This summary is merely provided to introduce a selection of concepts that are further described below in the detailed description, and is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
In the embodiments discussed hereinafter, a gas cooking appliance may generate various indications associated with ignition of a gas burner. In some embodiments, for example, a control circuit may be used to generate an audible and/or visual indication to a user when a user control for a gas burner is in a position within which an igniter is active and a gas valve is supplying sufficient gas flow to the gas burner to support ignition and thereby assist a user in properly positioning the user control during ignition of the burner. Further, in some embodiments, a control circuit may be used to generate an audible and/or visual indication to a user while an igniter is activated to notify the user that the igniter is active.
Turning now to the drawings, wherein like numbers denote like parts throughout the several views,
Cooking appliance 10 may also include various user interface devices, including, for example, a control panel 26 incorporating a plurality of rotary burner controls 28 and a user interface or display 30 for providing visual feedback as to the activation state of the cooking appliance. In some embodiments, each rotary burner control 28 may include an associated electronic burner control user interface or display 32 that is disposed on or adjacent to a knob or rotary control actuator of the rotary burner control 28, while in other embodiments, no control-specific displays may be used. It will be appreciated that cooking appliance 10 may include various types of user controls in other embodiments, including various combinations of switches, buttons, knobs and/or sliders, typically disposed at the rear or front (or both) of the cooking appliance. Further, in some embodiments, one or more touch screens may be employed for interaction with a user. As such, in some embodiments, display 30 may be touch sensitive to receive user input in addition to displaying status information and/or otherwise interacting with a user. In still other embodiments, cooking appliance 10 may be controllable remotely, e.g., via a smartphone, tablet, personal digital assistant or other networked computing device, e.g., using a web interface or a dedicated app. In some embodiments, both the cooktop burners and the oven may be controlled by the same electronic control system, while in other embodiments, different control systems may be used for separate control of each system.
Each of user interfaces/displays 30, 32 may also vary in different embodiments, and may include individual indicators, segmented alphanumeric displays, and/or dot matrix displays, and may be based on various types of display technologies, including LEDs, vacuum fluorescent displays, incandescent lights, etc. Further, in some embodiments audio feedback may be provided to a user via one or more speakers, and in some embodiments, user input may be received via a spoken or gesture-based interface.
As noted above, cooking appliance 10 of
In turn, a cooking element may be considered to include practically any type of energy-producing element used in residential applications in connection with cooking food, e.g., employing various cooking technologies such as electric, gas, light, microwaves, induction, convection, radiation, etc. In the case of an oven, for example, one or more cooking elements therein may be gas, electric, light, or microwave heating elements in some embodiments, while in the case of a cooktop, one or more cooking elements therein may be gas, electric, or inductive heating elements in some embodiments. Further, it will be appreciated that any number of cooking elements may be provided in a cooking appliance (including multiple cooking elements for performing different types of cooking cycles such as baking or broiling), and that multiple types of cooking elements may be combined in some embodiments, e.g., combinations of microwave and light cooking elements in some oven embodiments. In the case of the embodiments discussed hereinafter, at least one of the cooking elements for the cooktop and/or oven includes a gas burner and a mechanical or electromechanical valve unit that couples the gas burner to a gas supply.
A cooking appliance consistent with the invention also generally includes one or more controllers configured to control the cooking elements and otherwise perform cooking operations at the direction of a user.
As shown in
Controller 42 may also be interfaced with various sensors 58 located to sense environmental conditions inside of and/or external to cooking appliance 40, e.g., one or more temperature sensors, humidity sensors, air quality sensors, smoke sensors, carbon monoxide sensors, odor sensors and/or electronic nose sensors, among others. Such sensors may be internal or external to cooking appliance 40, and may be coupled wirelessly to controller 42 in some embodiments.
In some embodiments, controller 42 may also be coupled to one or more network interfaces 60, e.g., for interfacing with external devices via wired and/or wireless networks such as Ethernet, Wi-Fi, Bluetooth, NFC, cellular and other suitable networks, collectively represented in
In some embodiments, controller 42 may operate under the control of an operating system and may execute or otherwise rely upon various computer software applications, components, programs, objects, modules, data structures, etc. In addition, controller 42 may also incorporate hardware logic to implement some or all of the functionality disclosed herein. Further, in some embodiments, the sequences of operations performed by controller 42 to implement the embodiments disclosed herein may be implemented using program code including one or more instructions that are resident at various times in various memory and storage devices, and that, when read and executed by one or more hardware-based processors, perform the operations embodying desired functionality. Moreover, in some embodiments, such program code may be distributed as a program product in a variety of forms, and that the invention applies equally regardless of the particular type of computer readable media used to actually carry out the distribution, including, for example, non-transitory computer readable storage media. In addition, it will be appreciated that the various operations described herein may be combined, split, reordered, reversed, varied, omitted, parallelized and/or supplemented with other techniques known in the art, and therefore, the invention is not limited to the particular sequences of operations described herein.
Numerous variations and modifications to the cooking appliances illustrated in
As noted above, embodiments consistent with the invention may generate one or more of several different types of indications to a user associated with ignition of a gas burner on a gas cooking appliance such as a cooktop, range, grill or oven, and associated with the ignition of a gas cooktop, grill or oven burner.
In some embodiments, and as illustrated in
In order to generate indications to a user, gas range 100 may include various types of electrical indicator devices, e.g., an illuminated light or LED-backlit ring 116, 118, 120 on each burner control 104, 106, 108, a separate, dedicated visual indicator such as an LED 122 on the control panel, an illuminated icon 124 and/or text displayed on a user interface 126, or a speaker 128 for use in generating audible indications. An indication could also be generated proximate the burner itself, e.g., using a light source positioned close to the burner. An indication, in this regard, may be considered to include any type of visual and/or audible presentation to a user that may be recognized as an alert by a user, and in some instances, an indication may be generated on a device that is remove from a cooking appliance, e.g., on an interconnected smart home device, mobile device, etc. It will also be appreciated that the various indications 116, 118, 120, 122, 124 and 128 illustrated in
In addition, it will be appreciated that indications may be generated using devices that may also be used to indicate other status information for a cooking appliance, and that indications in some embodiments may utilize different colors, animations, patterns, text, graphical images, etc. In one example embodiment, ignition-related indications may be implemented by light rings 116, 118, 120, and that additional indications associated with the respective user controls 104, 106, 108 may also be generated using the same light rings 116, 118, 120. For example, a light ring 116, 118, 120 may be used to display a first color or pattern (e.g., a red color and/or a flashing or chasing lights pattern) to represent when the igniter of the associated burner is on or when the control actuator 110, 112, 114 is in an ignition position, and then display a second color or pattern (e.g., a blue color and/or a solid illumination pattern) to represent when the control actuator 110, 112, 114 is in an “on” position and a flame is detected. Further indications, e.g., related to flame loss or other error conditions, may also be displayed in a similar manner.
With further reference to
Control over cooking appliance 100 may be provided by a control circuit 142, which may include a controller 144 in some embodiments. Control circuit 142 may drive one or more audible and/or visual indicators 146 (which may correspond, for example, to any of elements 122, 124 or 128 of
Further, in some embodiments, each burner control 104, 108 may include an associated position sensor 152, 154 that is used to detect a position of the associated control actuator 110, 114. Each position sensor 152, 154 may be implemented using practically any type of sensor capable of detecting an absolute position and/or relative movement of the rotary control actuator, e.g., an encoder, one or more microswitches, etc. While in some embodiments, a position sensor 152, 154 may have a resolution sufficient to indicate a specific position, in other embodiments a position sensor may only be sufficient to indicate when the control actuator is within a larger range of positions, e.g., in the case of a cam-driven switch that is activated throughout a relatively large range of positions of a control actuator.
As noted above, cooking appliance 100 relies on mechanical gas valves that are mechanically coupled to burner controls. In other embodiments, however, burner controls may be coupled electronically, rather than mechanically, to electromechanical valves for the purpose of controlling a gas burner.
With further reference to
Each burner control, e.g., burner control 110, generally includes, in addition to a control actuator, an electronic burner control user interface or display 222, light ring 216, and secondary control 226. In addition, each burner control may also include a position sensor 242, which in the illustrated embodiment is implemented as an encoder such as an A-quad-B encoder, but could also be implemented using other encoders or switches. In some embodiments, each burner control may be a rotary burner control, and may include a rotary control actuator such as a knob, ring or wheel. In the illustrated embodiment, the rotatable knob may be a continuous rotatable knob that is infinitely rotatable in both directions, while in other embodiments the knob may be rotatable only within a limited range.
An electronic burner control user interface or display may also be implemented in a number of manners in different embodiments. In the illustrated embodiment, for example, each electronic burner control user interface or display may be implemented using a multi-segment, multi-digit LED display. In other embodiments, however, such a user interface or display may be positioned in other locations adjacent the rotary control actuator, or even on the rotary control actuator itself. In some embodiments, e.g., where a rotary control actuator is a ring or wheel, such a user interface or display may be positioned on a stationary front or side surface proximate or on the rotary control actuator. In addition, the user interface or display is generally dedicated to a particular burner and rotary burner control such that the user interface or display only displays status information related to that burner and rotary burner control, e.g., a current output power level of the burner (e.g., a numerical value or label such as 0-10, a percent, a descriptor such as “low,” “medium,” or “high,”, etc.). In other embodiments, however, other user interface technologies may be used, e.g., using dot-matrix panels, LED or LCD panels, vacuum fluorescent displays, discrete illumination sources, etc. Furthermore, user interfaces or displays may support multiple burners and rotary burner controls in some embodiments, e.g., to display status information for multiple burners having closely-positioned rotary burner controls. In still other embodiments, a single user interface or display may be used for all gas and/or cooktop burners.
Each light ring 216 may be implemented using one or more LED indicators that illuminate various portions of the burner control, and that in some embodiments may also convey additional status information, e.g., a rotary position indicator, a color or animation representing on/off status, hot burner status, and ignition-related indications as discussed herein. In other embodiments, no illumination may be supported, so backlit ring 216 may be omitted.
Each secondary control 226 may be used to provide a secondary source of user input to supplement the rotational input received via rotation of the control actuator, e.g., to activate or deactivate the gas burner, to ignite the gas burner, or provide other user input. The secondary control 226 may be implemented using a touch sensor, a mechanical or magnetic switch on rotary control actuator, a mechanical or magnetic switch capable sensing axial movement of the control actuator itself, or any other sensor capable of sensing an axial force applied generally along the axis of rotation of the rotary control actuator. In other embodiments, a secondary control may be implemented separately from a control actuator (e.g., adjacent thereto on the control panel) or may be omitted entirely.
Each position sensor 242 may be implemented using practically any type of sensor capable of detecting an absolute position and/or relative movement of the rotary control actuator, e.g., an encoder, one or more microswitches, etc. In one embodiment, an A-quad-B encoder may be used to indicate both a direction and extent of relative rotation of the rotary control actuator.
Control over appliance 200 may be provided by a control circuit 244, which in some embodiments may include a controller 246 and one or more audible and/or visual indicators 248, and which may control ignition of burners 202, 236 using igniters and flame detectors 250, 252, e.g., implementing automatic re-ignition functionality. Controller 246 in the illustrated embodiment may be used to execute instructions that implement software-based control over appliance 200; however, it will be appreciated that various aspects of the invention described herein may be implemented in control circuits lacking any controllers or other software-based functionality, so the invention is not limited to software-based controls and the like.
Now turning to
Furthermore, where automatic re-ignition is supported, events such as spills (e.g., due to boil-over from a pan or pot on a burner), drafts (e.g., due to open doors, fans, etc.) or other related occurrences may cause flame loss, and an automatic ignition system may be capable of detecting the flame loss with a flame detector or sensor and then attempting re-ignition of the burner. Nonetheless, it may not even be apparent to a user that the flame was lost and that the appliance is attempting to re-ignite the burner if the user cannot hear the sparking or see the burner. If the user is unaware, the cooking process can be shut off without the user's knowledge.
While flame loss systems may alert a user when a flame is lost and re-ignition is unsuccessful, generally a user is not alerted when a flame loss occurs but successful re-ignition has been attained. Thus, for example, if an open door is causing a burner to periodically experience flame loss, as long as the user is unaware that the re-ignition is being performed, the user would not think to address the underlying cause of the flame out—the open door—and thereby mitigate future flame losses.
In some embodiments consistent with the invention, however, it may be desirable to utilize a control circuit in a cooking appliance to generate an indication to a user in connection with activating the igniter when gas is flowing to the gas burner and thereby notify the user that the igniter is active. In contrast with a flame loss alert, an active igniter indication may be used to indicate when ignition is being attempted, even when due to the surrounding environment a user is unable to hear or see the igniter, and thus bring to the attention of a user potential issues present within the environment that may be affecting the burner's ability to remain lit. As such, an active igniter indication may be considered to be separate from any visual and/or audible outputs of the igniter itself.
Active igniter indications may be implemented in a number of different manners in different embodiments.
Positions A-D illustrate various representative locations in which an visual or audio device such as an LED, indicator light, light ring, speaker, etc. may be positioned in the circuit to generate an indication in connection with activation of the igniter. Positions A and B represent low voltage side positions, with position A being in series with switch 266 and position B being in parallel with switch 266, while positions C and D represent high voltage side positions, with position C being in series with igniter 262 and position D being in parallel with igniter 262. In the event that the device is coupled on the high voltage side, the device may flash with every spark. Other suitable positions and circuit will be apparent to those of ordinary skill having the benefit of the instant disclosure.
Even in cooking appliances that utilize software-based control and/or utilize electromechanical gas valves, active igniter indications may be of use, particularly in connection with cooking appliances incorporating automatic re-ignition functionality.
If the burner is deactivated or shut off, control may pass back to burner off state 282. However, if a flame loss is detected, the igniter may be turned on, causing a transition to occur to a re-ignition alert state 288, during which an active igniter indication is generated, thereby indicating to a user that the appliance is attempting to re-ignite the burner. If a successful re-ignition occurs, e.g., as detected by a flame detector, a transition may occur back to state 286, turning off the indication. Further, if ignition or re-ignition is determined to be unsuccessful in either state 284 or state 288, e.g., as a result of a time-out with no flame detected, an ignition error may be signaled, and the burner turned off, with the state transitioning to burner off state 282.
In some embodiments, it may be desirable to use different indications based upon whether the burner is being ignited or re-ignited. In some embodiments, for example, it may be desirable to make the indication associated with re-ignition more pronounced than that used for the initial indication, given that the re-ignition has presumably occurred due to an unexpected flame loss and that the user may not be devoting as much attention to the cooking appliance as when he or she is first igniting the burner. It may also be desirable to enable a user to disable indications for ignitions and/or re-ignitions, e.g., through user settings.
Thus, embodiments consistent with this aspect of the invention may enable a user to be alerted whenever an igniter is active, and thereby verify correct operation of the cooking appliance. In many instances a user may also be sufficiently alerted even if the user is on the other side of a loud kitchen or otherwise attending to other activities in the kitchen and otherwise unaware that a flame loss has occurred and re-ignition is being attempted.
Now turning to
In order to prevent the flow of unburned gas, the switch is generally designed to change state (and thus initiate sparking) just before the point in the gas valve's rotation when gas begins to flow. The switch is designed to remain in this state to allow sparking to continue until just before the valve reaches its maximum flow position. In many cases, e.g., for a gas valve with a 270 degree range of rotation, this state change generally occurs somewhere around 85 degrees open from the off position. The maximum flow position for the valve is generally about 90 degrees open from the off position, and this is the first position that the user is intended to use and thus sparking generally should not occur at this 90 degree position.
However, it will be appreciated that ignition of the burner flame is easier to achieve near the maximum flow position of the gas valve. This means that although sparking begins before gas flow begins, ignition generally occurs best closer to the 85 degree position, when there is more flow. When the flow is smaller, the burner may not ignite at all as the flow may not be sufficient to support flames at the burner ports. So there are positions at which sparking will occur, but burner ignition cannot be achieved.
It has been found, however, that sometimes users are not aware of the proper position for igniting the burner. They may think that the burner should ignite in any valve position that causes the igniter to spark, and they may be forced to adjust the position of the knob back and forth until ignition occurs. Further, some users may be overly concerned with overshooting the igniter and causing gas to flow from the burner at a high rate, so such users may naturally skew towards a position near the beginning of the igniter activation, where gas flow may be insufficient.
Some appliances attempt to assist a user with positioning by printing text or icons on a knob or on a control panel to suggest a position for ignition to occur. However, it has been found that such graphics are highly vague and imprecise, and generally insufficient to properly guide a user to a position where ignition can occur.
Embodiments consistent with the invention, on the other hand, seek to generate an indication to a user whenever a burner control for a gas burner is in a suitable position for igniting the burner.
In some embodiments, for example, a burner control may be movable between first, second, third and fourth ranges of positions. In the first range of positions (generally corresponding to the 0 to 20 degree range in the example of
It will be appreciated that a burner control consistent with the invention need not be a rotary control.
A control circuit may generate ignition position indications in various manners in various embodiments. In one example embodiment, and as illustrated in
One manner of configuring switches 326 and 328 to implement the herein-described functionality is illustrated by burner control 330 of
An ignition position indication may also be used in other cooking appliance designs, including those implementing software-based control and/or using electromechanical gas valves.
Self-Clean Disable: it may be desirable in some embodiments to detect when any valve is open and flowing gas (i.e., not in the first range), and use this detection to enable or disable a self-clean function of the range. It may be desirable or necessary in some designs, for example, to disallow the use of a cooktop when an oven is in self-clean mode.
Ignition Alert: it may be desirable in some embodiments to detect if a valve is left in the second or third range for an extended period of time and signal an alert to signal cases in which a knob or other burner control may have been unintentionally rotated out of the first or fourth ranges.
Flame Loss Alert: it may be desirable in some embodiments to detect if a valve is in any of the second, third or fourth ranges for an extended period of time and no flame is detected.
It will be appreciated that any of these additional conditions may be implemented separately in different embodiments.
Sequence 400 utilizes four states, an “off” state where the burner is off (the first range discussed above), an “igniter” state where the igniter is on but insufficient gas flow is present to support ignition (the second range discussed above), an “alert” state where the igniter is on and sufficient gas flow is present to support ignition (the third range discussed above), and an “active” state where the igniter is off and sufficient gas flow is present to support ignition (the fourth range discussed above). Sequence 400 also utilizes a flame detector and a pair of timers, a not active timer that determines how long the valve is in the second or third range and a no flame timer that determines how long the valve is in any of the second, third or fourth ranges with no flame detected.
Sequence 400 loops through a series of determinations illustrated in blocks 402-420. Block 402 determines whether a flame is detected, and blocks 406 and 408 determine whether either of the not active or no flame timers have expired. Block 408 determines whether a state has changed (e.g., based on burner control position or switch activation), and blocks 410-420 handle each of the state transitions.
Block 410, for example, detects a state change from off to igniter, and calls block 422 to start the not active and no flame timers and calls block 424 to disable self-clean. Block 412 detects a state change from igniter to alert, and calls block 426 to enable the ignition position indication. Block 414 detects a state change from alert to active, and calls block 428 to stop the not active time and block 430 to disable the ignition position indication. Block 416 detects a state change from active to alert, and calls block 432 to start the not active timer. Block 418 detects a state change from alert to igniter, and calls block 434 to disable the ignition position indication. Block 420 detects a state change from igniter to off, and calls block 436 to stop the timers and calls block 438 to enable self-clean.
Block 402, as noted above, determines whether a flame is detected, and so long as a flame is detected, block 440 is called to reset the no flame timer, while blocks 404 and 406 detect whether the not active or no flame timers are expired, and responsive thereto enable the appropriate indications in blocks 442, 444.
It will be appreciated that various modifications may be made to the embodiments discussed herein, and that a number of the concepts disclosed herein may be used in combination with one another or may be used separately. Therefore, the invention lies in the claims hereinafter appended.
