Sequential dual evaporator refrigerator and method of controlling same

Abstract

A refrigerator and method are provided where the refrigerator includes at least a refrigerator compartment (C 2 ) cooled by a refrigerator evaporator, a freezer compartment (C 1 ) cooled by a freezer evaporator, a compressor, a controller, and a valve that selectively couples the compressor to a selected one of the refrigerator evaporator and the freezer evaporator. The method includes determining both refrigerator and freezer compartment cooling priorities as a function of the respective actual refrigerator or freezer compartment temperatures, desired refrigerator or freezer compartment temperatures, and refrigerator or freezer hysteresis. The refrigerator and freezer compartment cooling priorities having one of the following priority levels: high, medium, low, and satisfied. The method further includes selecting a current refrigerator system mode in response to the refrigerator and freezer compartment cooling priorities.

1 . A method for controlling a refrigerator having at least a refrigerator compartment cooled by a refrigerator evaporator, a freezer compartment cooled by a freezer evaporator, a compressor, and a valve that selectively couples the compressor to a selected one of the refrigerator evaporator and the freezer evaporator, the method comprising the steps of:
 determining a refrigerator compartment cooling priority as a function of the actual refrigerator compartment temperature, a desired refrigerator compartment temperature, and a refrigerator hysteresis, wherein the refrigerator compartment cooling priority has one of the following priority levels: high, medium, low, and satisfied;   determining a freezer compartment cooling priority as a function of the actual freezer compartment temperature, a desired freezer compartment temperature, and a freezer hysteresis, wherein the freezer compartment cooling priority has one of the following priority levels: high, medium, low, and satisfied;   selecting a current refrigerator system mode in response to a refrigerator compartment cooling priority and a freezer compartment cooling priority, the current refrigerator system mode is selected from at least the following modes: a pull down mode during which both the freezer and refrigerator compartments are alternatingly and periodically cooled, a refrigerator compartment cooling mode in which the refrigerator compartment is cooled, a freezer compartment cooling mode in which the freezer compartment is cooled, and a satisfied mode in which neither the refrigerator or freezer compartments are cooled; and   controlling the valve and the compressor to selectively cool one, both or neither of the refrigerator compartment and the freezer compartment based on the current refrigerator system mode.   
     
     
         2 . The method of  claim 1 , wherein the freezer hysteresis is different from the refrigerator hysteresis. 
     
     
         3 . The method of  claim 1 , wherein the freezer hysteresis is greater than the refrigerator hysteresis. 
     
     
         4 . The method of  claim 1 , wherein the refrigerator system mode is set to satisfied mode when both the refrigerator compartment cooling priority and the freezer compartment cooling priority are in the satisfied priority levels. 
     
     
         5 . The method of  claim 1 , wherein the refrigerator system mode is set to pull down mode when both the refrigerator compartment cooling priority and the freezer compartment cooling priority are in the high priority levels. 
     
     
         6 . The method of  claim 1 , wherein the refrigerator system mode is set to refrigerator compartment cooling mode when the refrigerator compartment cooling priority is greater than the freezer compartment cooling priority, or when the actual refrigerator compartment temperature is higher than the desired refrigerator compartment temperature minus the refrigerator hysteresis, and the freezer compartment cooling priority is not at the high priority level. 
     
     
         7 . The method of  claim 1 , wherein the refrigerator system mode is set to freezer compartment cooling mode when the freezer compartment cooling priority is at the high priority level and the refrigerator compartment cooling priority is not at the high priority level, or when the actual refrigerator compartment temperature is lower than the desired refrigerator compartment temperature minus the refrigerator hysteresis. 
     
     
         8 . The method of  claim 1 , wherein:
 the refrigerator compartment cooling priority is determined to be in a satisfied priority level when the actual refrigerator compartment temperature minus the desired refrigerator compartment temperature is less than or equal to the refrigerator hysteresis; and   the freezer compartment cooling priority is determined to be in a satisfied priority level when the actual freezer compartment temperature minus the desired freezer compartment temperature is less than or equal to the freezer hysteresis.   
     
     
         9 . The method of  claim 1 , wherein:
 the refrigerator compartment cooling priority is determined to be in a high priority level when the actual refrigerator compartment temperature minus the desired refrigerator compartment temperature is greater than or equal to a sum of a refrigerator compartment high priority constant and the refrigerator hysteresis; and   the freezer compartment cooling priority is determined to be in a high priority level when the actual freezer compartment temperature minus the freezer refrigerator compartment temperature is greater than or equal to a sum of a freezer compartment high priority constant and the freezer hysteresis.   
     
     
         10 . The method of  claim 9 , wherein the freezer compartment high priority constant is greater than the refrigerator compartment high priority constant. 
     
     
         11 . The method of  claim 9 , wherein the freezer hysteresis is greater than the refrigerator hysteresis. 
     
     
         12 . The method of  claim 1 , wherein:
 the refrigerator compartment cooling priority is determined to be in a medium priority level when the actual refrigerator compartment temperature minus the desired refrigerator compartment temperature is: (1) greater than a sum of a refrigerator compartment medium priority constant and the refrigerator hysteresis, and (2) less than or equal to a sum of a refrigerator compartment high priority constant and the refrigerator hysteresis; and   the freezer compartment cooling priority is determined to be in a medium priority level when the actual freezer compartment temperature minus the freezer refrigerator compartment temperature is: (1) greater than a sum of a freezer compartment medium priority constant and the freezer hysteresis, and (2) less than or equal to a sum of a freezer compartment high priority constant and the freezer hysteresis.   
     
     
         13 . The method of  claim 12 , wherein the freezer compartment high priority constant is greater than the refrigerator compartment high priority constant. 
     
     
         14 . The method of  claim 12 , wherein the freezer compartment medium priority constant is greater than the refrigerator compartment medium priority constant. 
     
     
         15 . The method of  claim 12 , wherein the freezer hysteresis is greater than the refrigerator hysteresis. 
     
     
         16 . The method of  claim 1 , wherein:
 the refrigerator compartment cooling priority is determined to be in a low priority level when the actual refrigerator compartment temperature minus the desired refrigerator compartment temperature is: (1) greater than the refrigerator hysteresis, and (2) less than or equal to a sum of a refrigerator compartment medium priority constant and the refrigerator hysteresis; and   the freezer compartment cooling priority is determined to be in a low priority level when the actual freezer compartment temperature minus the freezer refrigerator compartment temperature is: (1) greater than the freezer hysteresis, and (2) less than or equal to a sum of a freezer compartment medium priority constant and the freezer hysteresis.   
     
     
         17 . The method of  claim 16 , wherein the freezer compartment medium priority constant is greater than the refrigerator compartment medium priority constant. 
     
     
         18 . The method of  claim 16 , wherein the freezer hysteresis is greater than the refrigerator hysteresis. 
     
     
         19 . A refrigerator comprising:
 a refrigerator compartment;   a freezer compartment;   a refrigerator compartment temperature sensor for sensing an actual refrigerator compartment temperature;   a freezer compartment temperature sensor for sensing an actual freezer compartment temperature;   a refrigerator evaporator associated with said refrigerator compartment;   a freezer evaporator associated with said freezer compartment;   a compressor;   a valve fluidly coupled between said compressor and said refrigerator evaporator and said freezer evaporator, wherein, in response to a valve control signal, said valve is selectively operative to open or close between said compressor and said refrigerator evaporator to allow or prevent refrigerant from flowing therebetween and to open or close between said compressor and said freezer evaporator to allow or prevent refrigerant from flowing therebetween; and   a controller electrically coupled to said compressor, said valve, said refrigerator compartment temperature sensor, and said freezer compartment temperature sensor, for turning said compressor on and off, for selecting operational states of said valve, and for determining a current refrigerator system mode in response to a refrigerator compartment cooling priority and a freezer compartment cooling priority, the current refrigerator system mode is selected from at least the following modes: a pull down mode during which both the freezer and refrigerator compartments are alternatingly and periodically cooled, a refrigerator compartment cooling mode in which the refrigerator compartment is cooled, a freezer compartment cooling mode in which the freezer compartment is cooled, and a satisfied mode in which neither the refrigerator or freezer compartments are cooled,   wherein the refrigerator compartment cooling priority has one of the following priority levels: high, medium, low, and satisfied, wherein the refrigerator compartment cooling priority is determined as a function of the actual refrigerator compartment temperature, a desired refrigerator compartment temperature, and a refrigerator hysteresis, and   wherein the freezer compartment cooling priority has one of the following priority levels: high, medium, low, and satisfied, wherein the freezer compartment cooling priority is determined of as a function of the actual freezer compartment temperature, a desired freezer compartment temperature, and a freezer hysteresis.   
     
     
         20 . The refrigerator of  claim 19 , wherein the freezer hysteresis is different from the refrigerator hysteresis. 
     
     
         21 . The refrigerator of  claim 19 , wherein the freezer hysteresis is greater than the refrigerator hysteresis. 
     
     
         22 . The refrigerator of  claim 19 , wherein said controller sets the refrigerator system mode to satisfied mode when both the refrigerator compartment cooling priority and the freezer compartment cooling priority are in the satisfied priority levels. 
     
     
         23 . The refrigerator of  claim 19 , wherein said controller sets the refrigerator system mode to pull down mode when both the refrigerator compartment cooling priority and the freezer compartment cooling priority are in the high priority levels. 
     
     
         24 . The refrigerator of  claim 19 , wherein said controller sets the refrigerator system mode to refrigerator compartment cooling mode when the refrigerator compartment cooling priority is greater than the freezer compartment cooling priority, or when the actual refrigerator compartment temperature is higher than the desired refrigerator compartment temperature minus the refrigerator hysteresis, and the freezer compartment cooling priority is not at the high priority level. 
     
     
         25 . The refrigerator of  claim 19 , wherein said controller sets the refrigerator system mode to freezer compartment cooling mode when the freezer compartment cooling priority is at the high priority level and the refrigerator compartment cooling priority is not at the high priority level, or when the actual refrigerator compartment temperature is lower than the desired refrigerator compartment temperature minus the refrigerator hysteresis. 
     
     
         26 . The refrigerator of  claim 19 , wherein said controller:
 sets the refrigerator compartment cooling priority to a satisfied priority level when the actual refrigerator compartment temperature minus the desired refrigerator compartment temperature is less than or equal to the refrigerator hysteresis; and   sets the freezer compartment cooling priority to a satisfied priority level when the actual freezer compartment temperature minus the desired freezer compartment temperature is less than or equal to the freezer hysteresis.   
     
     
         27 . The refrigerator of  claim 19 , wherein said controller:
 sets the refrigerator compartment cooling priority to a high priority level when the actual refrigerator compartment temperature minus the desired refrigerator compartment temperature is greater than or equal to a sum of a refrigerator compartment high priority constant and the refrigerator hysteresis; and   sets the freezer compartment cooling priority to a high priority level when the actual freezer compartment temperature minus the freezer refrigerator compartment temperature is greater than or equal to a sum of a freezer compartment high priority constant and the freezer hysteresis.   
     
     
         28 . The refrigerator of  claim 27 , wherein the freezer compartment high priority constant is greater than the refrigerator compartment high priority constant. 
     
     
         29 . The refrigerator of  claim 27 , wherein the freezer hysteresis is greater than the refrigerator hysteresis. 
     
     
         30 . The refrigerator of  claim 19 , wherein said controller:
 sets the refrigerator compartment cooling priority to a medium priority level when the actual refrigerator compartment temperature minus the desired refrigerator compartment temperature is: (1) greater than a sum of a refrigerator compartment medium priority constant and the refrigerator hysteresis, and (2) less than or equal to a sum of a refrigerator compartment high priority constant and the refrigerator hysteresis; and   sets the freezer compartment cooling priority to a medium priority level when the actual freezer compartment temperature minus the freezer refrigerator compartment temperature is: (1) greater than a sum of a freezer compartment medium priority constant and the freezer hysteresis, and (2) less than or equal to a sum of a freezer compartment high priority constant and the freezer hysteresis.   
     
     
         31 . The refrigerator of  claim 30 , wherein the freezer compartment high priority constant is greater than the refrigerator compartment high priority constant. 
     
     
         32 . The refrigerator of  claim 30 , wherein the freezer compartment medium priority constant is greater than the refrigerator compartment medium priority constant. 
     
     
         33 . The refrigerator of  claim 30 , wherein the freezer hysteresis is greater than the refrigerator hysteresis. 
     
     
         34 . The refrigerator of  claim 19 , wherein said controller:
 sets the refrigerator compartment cooling priority to a low priority level when the actual refrigerator compartment temperature minus the desired refrigerator compartment temperature is: (1) greater than the refrigerator hysteresis, and (2) less than or equal to a sum of a refrigerator compartment medium priority constant and the refrigerator hysteresis; and   sets the freezer compartment cooling priority to a low priority level when the actual freezer compartment temperature minus the freezer refrigerator compartment temperature is: (1) greater than the freezer hysteresis, and (2) less than or equal to a sum of a freezer compartment medium priority constant and the freezer hysteresis.   
     
     
         35 . The refrigerator of  claim 34 , wherein the freezer compartment medium priority constant is greater than the refrigerator compartment medium priority constant. 
     
     
         36 . The refrigerator of  claim 34 , wherein the freezer hysteresis is greater than the refrigerator hysteresis. 
     
     
         37 . The refrigerator of  claim 19  further comprises a user input interface coupled to said controller for allowing a user to manually select the desired refrigerator compartment temperature and the desired freezer compartment temperature. 
     
     
         38 . The refrigerator of  claim 19  further comprises a refrigerator fan coupled to said controller for moving air past said refrigerator evaporator into said refrigerator compartment, wherein said controller turns said refrigerator fan on and off. 
     
     
         39 . The refrigerator of  claim 38  further comprises a freezer fan coupled to said controller for moving air past said freezer evaporator into said freezer compartment, wherein said controller turns said freezer fan on and off.