Power control for appliance having a glass ceramic cooking surface

Claim 2

In a household cooking appliance of the type having a glass ceramic cooking surface for supporting loads to be heated, and at least one radiant heating unit disposed beneath the glass ceramic cooking surface to heat loads supported thereon, a power control system comprising: temperature sensing means for sensing the temperature of the underside of the glass ceramic support surface proximate the heating unit; user actuable input selection means for enabling the user to select one of a plurality of power settings for the heating unit; at least one of said plurality of power settings having associated with it predetermined maximum and minimum reference temperatures defining a temperature band representative of the steady state temperature range of the underside of the glass ceramic support surface proximate the heating unit when heating loads at that power setting; and power control means responsive to the input selection means, operative to operate the heating unit at a steady state power level corresponding to the user selecting power setting; said power control means including means responsive to said temperature sensing means for operating the heating unit at a power level other than the power level corresponding to the user selected power setting when the sensed glass ceramic support surface temperature is outside said predetermined reference temperature band associated with the selected power setting to cause the heating unit to respond quickly to changes in the user selected power setting.

Claim 3

The power control system of claim 1 wherein said means responsive to said temperature sensing means for operating sad heating unit at a power level other than the power level associated with the user selected power setting is operative to apply a power level higher than the power level associated with the user selected power setting when the sensed temperature is below said predetermined temperature band for the selected power setting and to apply a power level lower than the power level associated with the user selected power setting when the sensed temperature is above said predetermined temperature band.

Claim 4

A power control system for a household cooking appliance of the type having a glass ceramic cooking surface for supporting loads to be heated and at least one radiant heating unit disposed beneath the glass ceramic cooking surface to heat loads supported on the cooking surface, said power control system comprising: temperature sensing means for sensing the temperature of the underside of the glass ceramic support surface approximate the heating unit; user actuable input selection means for enabling the user to select one of a plurality of power settings for the heating unit; at least one of said plurality of power settings having associated with it predetermined maximum and minimum reference temperatures defining a temperature band representative of the steady state temperature range of the underside of the glass ceramic support surface proximate the heating unit when heating loads at that power setting; and power control means responsive to the input selection means for operating the heating unit at a predetermined steady state power level corresponding to the user selected power setting including means responsive to said temperature sensing means operative to operate the heating unit at a power level higher than the power level corresponding to the user selected power setting when the sensed glass ceramic support surface temperature is less than said minimum reference temperature and to operate the heating unit at a power level less than the power level corresponding to the user selected power setting when the sensed glass ceramic support surface temperature is higher than the said maximum reference temperature to reach steady state operating conditions associated with the newly selected power setting.

Claim 5

A power control system for a household cooking appliance of the type having a glass ceramic cooking surface for supporting loads to be heated and at least one radiant heating unit disposed beneath the glass ceramic cooking surface to heat loads supported on the cooking surface, said power control system comprising: temperature sensing means for sensing the temperature of the underside of the glass ceramic support surface approximate the heating unit; user actuable input selection means for enabling the user to select one of a plurality of power settings for the heating unit; at least one of said plurality of power settings having associated with it predetermined maximum and minimum reference temperatures defining a temperature band representative of the steady state temperature range of the underside of the glass ceramic support surface proximate the heating unit when heating loads at that power setting; and power control means responsive to the input selection means for operating the heating unit at a predetermined steady state power level corresponding to the user selected power setting including means responsive to said temperature sensing means operative to operate the heating unit at a power level higher than the power level corresponding to the user selected power setting when the sensed glass ceramic support surface temperature is less than said minimum reference temperature and to operate the heating unit at a power level less than the power level corresponding to the user selected power setting when the sensed glass ceramic support surface temperature is higher than the said maximum reference temperature to reach steady state operating conditions associated with the newly selected power setting.

Claim 6

The power control system of claim 3 wherein said minimum reference temperature represents a temperature level which the system will normally at least reach under steady state conditions when heating a relatively dark flat bottomed utensil at the steady state power level for selected power setting and the maximum reference temperature corresponds to a temperature which would normally not be exceeded when heating a relatively bright aluminum utensil having a warped bottom surface when at said corresponding power level.

Claim 7

The power control system of claim 4 wherein said means for operating the heating unit at power levels other than the power level corresponding to the selected power setting is operative to operate the heating unit at a predetermined number of power levels higher than the power level selected when the sensed glass ceramic support surface temperature is less than said minimum reference temperature and a predetermined number of power levels lower than the steady state power level associated with the selected power setting when the sensed glass support surface temperature is greater than said maximum reference temperature for the selected power setting.

Claim 10

The method of claim 6 wherein the predetermined glass ceramic support surface temperature range for each of said user selectable power settings is defined by a minimum reference temperature representing the temperature which will normally be reached when heating a relatively dark flat bottomed pan at the power level associated with the user selected power setting and a maximum reference temperature representative of the temperature which will normally not be exceeded by a pan having a warped relatively bright aluminum bottom surface when operated at the power level associated with the selected power setting.