Abstract:
A control system for a cooking appliance enables a consumer to selectively program a cooking appliance through a control panel in a conventional mode based on established cooking times and temperatures, as well as in a simplified mode incorporating a minimal number of programming steps. In the simplified mode, the consumer selects a first, non-temperature related special features button and inputs a cook time. Immediately following input of the cook time, the control system starts a cooking operation. If the selected time is greater than a predetermined value, the control system automatically operates the cooking appliance in a cold start mode. An override is provided to disable the cold start mode if so desired. In addition, the control system allows a consumer to input both minimum and maximum cook times for the cooking operation.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention pertains to the art of cooking appliances and, more particularly, to a cooking appliance including a control system having a simplified programming algorithm for initiating a cooking operation. 
   2. Discussion of the Prior Art 
   Over the years, there have been many advances in the art of cooking appliances. Various heat sources, such as convection air, microwave and IR heating elements have been used, in one way or another, to perform a cooking operation. Mechanical components such as switches, thermostats and other controls have been replaced, or at least supplemented, by electronic control systems. Rotary knobs are slowly giving way to touch pads and touch screen displays. Many new features have been added to the cooking appliance, such as preprogrammed operations, recipes, and multi-stage cooking operations. Many appliances include a help screen that aides a consumer in navigating through various available options. All in all, the construction and internal programming of the cooking appliance has grown to be more complicated. However, the basic steps for initiating a cooking operation have remained substantially unchanged over the years. 
   Typically, to initiate a cooking operation, a consumer may select a cooking mode, a cooking temperature, a cook time and a cook duration. In the most simplified form, the consumer may select the cook mode and cook temperature. The prior art contains several examples of cooking appliances that attempt to reduce an overall number of steps required to initiate a cooking operation. For example, U.S. Pat. No. 3,783,769 discloses a cooking appliance having a computer cooking means that, after placing a meat product into a cooking chamber, requires only an input indicating the type of meat and the degree of doneness before the cooking operation is started. While being simple, the process does not readily lend itself to other food items, such as baked goods and the like. 
   In addition, if a consumer desires to set a cook duration, he/she is limited to entering a single time. Most recipes call for performing a cooking operation over a range of cook times. Another consideration is that heating characteristics vary between cooking appliances. Where a food item will require heating for 30 minutes in one model, the same food item may require heating for 35 or even 40 minutes in a different model. For that reason, most recipes set forth both upper and lower limits for the cook time. Often times, a consumer will set a food item in the oven for the minimum time, only to find that the food item is not completely cooked. At that point, the food item is left in the oven for an additional time period which, if the timer is not set again or if the consumer simply looses track of the time, could lead to the food item becoming overcooked or even burned. 
   Based on the above, there exists a need for a cooking appliance requiring minimal inputs before initiating a cooking operation. In addition, there exists a need for a cooking appliance having a timer capable of setting both minimum and maximum cook time parameters. More specifically, given the sophistication provided by modern technology, the overall number of steps required to initiate a cooking operating could be further reduced, while not being limited by the particular type of food being cooked. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to a control system for a cooking appliance which enables a consumer to perform a complete cooking operation with a minimal number of control inputs. In general, the invention enables a consumer to program the cooking appliance through a control panel in a conventional manner based on established cooking times and temperatures in accordance with recipes or other cooking instructions. However, under circumstances wherein the consumer would like to initiate a cooking process with a minimal number of steps after placing a food item into the appliance, a cooking operation can be started with just two, non-temperature related input parameters to the control system. 
   In accordance with the most preferred form of the invention, a special feature control button is provided on the control panel for the cooking appliance. The special feature button signals the control system that, after a cook time is inputted, a cooking operation should be automatically started. That is, the consumer need only press the special features button and input a cook time to initiate the cooking operation. In the most preferred embodiment, after the special feature button is selected and if the cook time is set above a minimum time period, e.g., 44 minutes, the control system will automatically initiate the cooking operation in a cold start mode. The cold start mode adjusts a temperature of the cooking appliance to establish a time-temperature relationship similar to that as if the cooking appliance went through a preheat cycle. In further accordance with the most preferred embodiment, the control system provides an override feature that, if a cold start is indicated, will allow the consumer to operate the cooking appliance in a standard mode. In the standard mode, the cooking appliance will initially perform a preheat cycle. Upon completion of the preheat cycle, the cooking appliance will provide a signal to the consumer that it is time to place the food item into an oven cavity of the cooking appliance. 
   In another embodiment, the consumer is presented with the option of inputting a single cook time or, alternatively, inputting both minimum and maximum cook times through the control panel. Prior to starting a cooking operation, the consumer can enter, such as through a timer pad, two cook times. A display portion of the control panel will prompt the consumer to first input a minimum cook time and, if so desired, a maximum cook time. Once the cooking operation has started, a timer will count down the time remaining for the minimum cook time. Once the minimum cook time has expired, a signal will indicate the cooking operation may be complete. If a maximum time is also selected, at the completion of the minimum cook time, the timer will count down the remaining time until the maximum cook time is compete. 
   Additional objects, features and advantages of the present invention will become more readily apparent from the following detailed description of a preferred embodiment when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a wall oven constructed in accordance with the present invention; 
       FIG. 2  is an enlarged view of a control panel employed in connection with the wall oven of  FIG. 1  illustrating operation with a special feature button in accordance with a preferred embodiment of the present invention; 
       FIG. 3  is an enlarged view of the control panel employed in connection with the wall oven of  FIG. 1 , illustrating selection of a minimum cook time in accordance with another aspect of the present invention; and 
       FIG. 4  is an enlarged view of the control panel employed in connection with the wall oven of  FIG. 1 , illustrating selection of a maximum cook time in accordance with the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   With initial reference to  FIG. 1 , a cooking appliance constructed in accordance with the present invention is generally indicated at  2 . Cooking appliance  2 , as depicted, constitutes a double wall oven. However, it should be understood that the present invention not limited to this model type and can be incorporated into various types of oven configurations, e.g., cabinet mounted ovens, as well as both slide-in and free standing ranges. In any event, in the embodiment shown, cooking appliance  2  constitutes a dual oven wall unit including an upper oven  4  having upper oven cavity  6  and a lower oven  8  having a lower oven cavity  10 . Cooking appliance  2  includes an outer frame  12  for supporting, at least in part, both upper and lower oven cavities  6  and  10 . 
   In a manner known in the art, cooking appliance  2  is equipped with a door assembly  14  to selectively provide access to upper oven cavity  6 . As shown, door assembly  14  includes a handle  15  at an upper portion  16  thereof. Door assembly  14  is adapted to pivot at a lower portion  18  to enable selective access to within oven cavity  6 . In a manner also known in the art, door  14  is provided with a transparent zone or window  22  for viewing the contents of oven cavity  6  while door  14  is closed. In the embodiment shown, a corresponding door assembly  24  including a handle  25  and a transparent zone or window  26  is provided to selectively access lower oven cavity  10 . 
   As best seen in  FIG. 1 , oven cavity  6  is defined by a bottom wall  27 , an upper wall  28 , opposing side walls  30  and  31  provided with a plurality of vertically spaced side rails  32 , and a rear wall  33 . In the preferred embodiment shown, bottom wall  27  is constituted by a flat, smooth surface designed to improve the cleanability of oven cavity  6 . Arranged about bottom wall  27  of oven cavity  6  is a bake element  40 . Also, a top broiler element  42  is arranged along upper wall  28  of oven cavity  6 . Top broiler element  42  is provided to enable a consumer to perform a grilling process in upper oven  4  and to aid in pyrolytic heating during a self-clean operation. More specifically, both bake element  40  and top broiler element  42  are constituted by sheathed electric resistive heating elements. 
   Based on the above, in the preferred embodiment depicted, cooking appliance  2  actually constitutes an electric, dual wall oven. However, it is to be understood that cooking appliance  2  could equally operate on gas, either natural or propane. In any case, both oven cavities  6  and  10  preferably employ both radiant and convection heating techniques for cooking food items therein. To this end, rear wall  33  is shown to include a convection fan or blower  44 . Although the exact position and construction of fan  44  can readily vary in accordance with the invention, in the embodiment shown, fan  44  draws in air at a central intake zone (not separately labeled) and directs the air into oven cavity  6  in a radial outward direction. As also clearly shown in this figure, another sheathed electric heating element  46 , which preferably takes the general form of a ring, extends circumferentially about fan  44  in order to heat the radially expelled air flow. At this point, it should be noted that a fan cover, which has not been shown for the sake of clarity of the drawings, extends about fan  44  and heating element  46 , preferably with the cover having an associated central inlet and a plurality of outer radial outlet openings. 
   As further shown in  FIGS. 1 and 2 , cooking appliance  2  includes an upper control panel  50  having a plurality of control elements. In accordance with one embodiment, the control elements are constituted by first and second sets of oven control buttons  52  and  53 , as well as a numeric pad  54 . Control panel  50  is adapted to be used to input desired cooking parameters for cooking appliance  2 . More specifically, the first and second sets of control buttons  52  and  53 , in combination with numeric pad  54  and a display  62 , enable a user to establish particular cooking operations for upper and lower ovens  4  and  8  respectively. 
   In one preferred embodiment particularly shown in  FIG. 2 , the first set of control buttons  52  includes a cancel button  80 , a convection button  82 , a bake button  84 , a broil button  86 , a clean button  87  and, as will be discussed more fully below, a special feature button  88  which is not related to any particular temperature setting for cooking appliance  2 . In addition, first set of control buttons  52  also preferably includes an oven light button  90  for activating an oven light  91  associated with upper oven  4  and a button  92  used to access more cooking options which are conveyed to the user through display  62 . In a corresponding manner, second set of control buttons  53  includes a cancel button  100 , a convection button  102 , a bake button  104 , a broil button  106 , a clean button  108  and a special features button  109 . Furthermore, second set of control buttons  53  also preferably includes an oven light button  110  for activating an oven light  111  associated with lower oven  85 , and a button  112  which is used to access more cooking options that are conveyed to the user through display  62 . 
   Display  62  is preferably divided into various sections. In accordance with the most preferred embodiment of the invention, an uppermost section of display  62  is sub-divided into three time display zones  140 – 142 . More specifically, leftmost display zone  140  constitutes a first timer zone having an associated timer button  145 . Central display zone  141  constitutes a clock for cooking appliance  2 . Rightmost display zone  142  constitutes a second timer zone having an associated timer button  148 . 
   Spaced below time display zones  140 – 142  are a series of vertically spaced information display zones  151 – 155 . Each of information display zones  151 ,  153  and  155  has associated left and right portions (not separately labeled). As shown, each of the left and right portions have associated therewith laterally positioned selection buttons  160 – 165 . As also shown, numeric pad  54  preferably enables alpha-numeric input. That is, in addition to presenting numbers 0–9, numeric pad  54  doubles as an input source for alpha information. To this end, in a manner somewhat analogous to a telephone keypad, the number 2 button functions for ABC letter entry; the number 3 button functions for DEF letter entry; the number 4 button functions for GHI letter entry; the number 5 button functions for JKL letter entry; the number 6 button functions for MNO letter entry; the number 7 button functions for PQRS letter entry; the number 8 button functions for TUV letter entry; and the number 9 button functions for WXYZ letter entry. The number 0 button can also be used to input a space. On either side of the number 0 button are Back and Enter buttons  175  and  176  which can be used in combination with the various alpha keys for information entry. Finally, provided adjacent numeric pad  54  are auto set, Help, Favorites and Setup buttons  180 – 183 . 
   In general, control panel  50  is linked to a controller or CPU  200  formed as part of an overall control system for cooking appliance  2 . Therefore, CPU  200  receives user inputs and selections through control panel  50 , as well as signals from sensors associated with cooking appliance  2 , i.e. oven temperature sensors for upper and lower ovens  4  and  8  as generally indicated at  210  and a fan speed sensor  215 . In turn, CPU  200  controls bake element  40 , top broiler element  42 , convection fan  44  and convection heating element  46  for upper oven cavity  6 . Of course, a corresponding control is available for lower oven cavity  10 . CPU  200  is also equipped with a memory module  230  for storing information associated with operating cooking appliance  2 . In any event, since the various programming and general operational characteristics of cooking appliance  2  do not form part of the present invention, these features will not be discussed further here. Instead, the present invention is particularly directed to the operation of the control system for cooking appliance  2 . 
   In accordance with the preferred embodiment of the present invention, cooking appliance  2  is operable in a first or standard mode and a second or special feature mode. In the standard mode, in order to initiate a cooking operation, a consumer would select a cooking process, such as bake and/or convection cooking through control elements  82  and/or  84 , input a temperature through numeric pad  54  and select a cook time and duration through, for example, timer button  145  in a manner known in the art. Alternatively, the consumer may, in accordance with the present invention, initiate a cooking operation through a simple two step procedure. That is, in accordance with the most preferred form of the present invention, selection of special feature button  88  allows the consumer to initiate a cooking operation by simply inputting a cook time as detailed below. 
   As represented in  FIG. 2 , after special feature button  88  is selected, display  62  will, preferably on line  151 , prompt the consumer to select a cook time parameter. At this point, the consumer inputs a cook time parameter through, for example, numeric pad  54 , or by repeated actuation of auto set button  180 . Activation of auto set button  18  increments the time displayed on line  153  in predetermined time intervals, for example 15 minute intervals. Alternatively, the consumer could add or subtract to the cook time through manipulation of slew buttons, i.e., up/down timer buttons (not shown) or through timer button  145 . In any event, immediately after inputting the desired cook time, CPU  200  automatically actuates at least one of heating elements  40 ,  42  and  46  to initiate a cooking operation. In accordance with the most preferred embodiment, cooking appliance  2  will initiate a bake mode at a predetermined temperature (e.g. 350 or 400° F.). Once the cooking operation has commenced, the consumer has the option to, if so desired, add convection cooking to the process by selecting button  82 . In addition, if at any time during the cooking operation the consumer desires to adjust a temperature of the oven, the consumer can simply press auto set button  180  and input the desired temperature through key pad  54 . Furthermore, if adjustment of the time parameter is desired, special features button  88  can be actuated which then prompts the consumer to select or adjust the desired cook time. 
   In further accordance with the preferred embodiment, CPU  200  will automatically initiate a cold start cooking operation in the event the selected time parameter exceeds a minimum value, for example 44 minutes. In general, the cold start mode automatically adjusts a temperature of oven cavity  6  during a first portion of the cooking cycle to allow for cooking from a cold start. The adjustment is accomplished by increasing a temperature in the oven cavity so as to provide a food item with the same time/temperature relationship that would be experienced if the food item where placed in oven cavity  6  after a preheat period. The general operation of the cold start mode is not considered part of the present invention and is actually described in detail in co-pending U.S. patent application Ser. No. 10/301,579 entitled “COLD START COOKING SYSTEM”, filed Nov. 22, 2002 and incorporated herein by reference. 
   The cold start feature preferably includes an override that directs CPU  200  to perform a cooking operation wherein oven cavity  6  is preheated and thereafter oven cavity  6  is maintained at a substantially constant temperature throughout the cooking operation. In accordance with one aspect of the invention, overriding the cold start operation is accomplished by activating and holding special feature button  88  for a predetermined period, e.g., three seconds. At this point, CPU  200  will respond with a signal, which could be both audible and visual, indicating that the cold start mode is de-selected. In order to reactivate the cold start feature, the consumer would once again simply press and hold special feature button  88  for a second predetermined period, again preferably about three seconds. When the cold start mode is deactivated, CPU  200  performs a preheat cycle for oven cavity  6 . At the termination of the preheat cycle, CPU  200  will provide a signal to the user which, in the most preferred form of the invention, will include an audible signal through activation of a piezoelectric electric buzzer  300  and a visual signal, such as by flashing oven light  91  while providing a prompt on display  62 . 
   In accordance with another aspect of the present invention as represented in  FIGS. 3 and 4 , the consumer can be presented with the option of inputting two cook times through control panel  50 . That is, as many of today&#39;s recipes call for cooking over a range of cook times, cooking appliance  2  enables the consumer to input both a minimum cook time and a maximum cook time through control panel  50 . After selecting a particular cooking process, such as through button  84 , display  62  prompts the consumer to select a minimum cook time ( FIG. 3 ). Through manipulation of for example, timer button  145 , key pad  54  or auto set button  180 , a minimum cook time parameter is input into CPU  200 . After the minimum cook time is set, the consumer is prompted to select a maximum cook time ( FIG. 4 ). For instance, display  62  can scroll to prompt a maximum cook time. At this point, a maximum cooking time parameter can be entered in a manner similar to that described above. In accordance with this feature, the consumer can choose not to enter a maximum cook time. In this situation, the consumer can simply press button  160  to bypass inputting the maximum cook time, followed by pressing button  164  to start the cooking operation. That is, the consumer can “pass over” selecting a maximum cook time by depressing button  160  when prompted to input the maximum time parameter. 
   In any event, after the cooking operation has started, timer  140  begins to count down the time remaining for the minimum cook time. Once timer  140  has counted down to zero, a signal will be provided by CPU  200 , such as in the form of a beep through a piezoelectric buzzer  300  and/or through display  62 , indicating the termination of the minimum cook time. At this point, if a maximum cook time was set, timer  140  begins to count down the difference between the minimum cook time and the time remaining for the maximum cook time. At any time, the consumer has the option of terminating the cooking process or allowing the maximum cook time to expire, at which point CPU  200  will deactivate the heating element(s). In a manner similar to that described above, upon termination of the maximum cook time, a signal is provided to the consumer. 
   In general, the control system of the present invention enables a consumer to activate a cooking operation through various modes. That is, a consumer can initiate a standard cook mode, a simplified cook mode or perform a cooking operation over a range of cook times such that a versatile control system is employed for the cooking operation. Although described with reference to a preferred embodiment of the present invention, it should be readily apparent to one of ordinary skill in the art that various changes and/or modifications can be made to the invention without departing from the spirit thereof. For instance, the particular title descriptions of the various control buttons have been presented for exemplary purposes only and various other titles could be employed. In addition, while the invention is described with regard to upper oven  4 , it should be readily apparent that the present invention is equally applicable to lower oven  6 , particularly through the use of special feature button  109 . In general, the invention is only intended to be limited by the scope of the following claims.