Patent Application
20130061620
The present invention generally relates to a sequential dual evaporator refrigerator, and more particularly relates to a particular method of controlling the same.
According to one aspect of the present invention, a method is disclosed 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 comprises the steps of: (a) determining the 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; (b) determining the 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; (c) 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 (d) 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.
According to another aspect of the present invention, a refrigerator is provided that comprises: 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 the refrigerator compartment; a freezer evaporator associated with the freezer compartment; a compressor; a valve fluidly coupled between the compressor and the refrigerator evaporator and the freezer evaporator, wherein, in response to a valve control signal, the valve is selectively operative to open or close between the compressor and the refrigerator evaporator to allow or prevent refrigerant from flowing therebetween and to open or close between the compressor and the freezer evaporator to allow or prevent refrigerant from flowing therebetween; and a controller electrically coupled to the compressor, the valve, the refrigerator compartment temperature sensor, and the freezer compartment temperature sensor. The controller is provided for turning the compressor on and off, for selecting operational states of the 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. 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 of as a function of the actual refrigerator compartment temperature, a desired refrigerator compartment temperature, and a refrigerator hysteresis. 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.
These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings.
In the drawings:
Reference will now be made in detail to the present preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.
Refrigerator 10 may further comprise a refrigerator compartment (RC) temperature sensor 22 for sensing an actual refrigerator compartment temperature; a freezer compartment (FC) temperature sensor 32 for sensing an actual freezer compartment temperature; and a controller 50 electrically coupled to compressor 40, valve 45, refrigerator compartment temperature sensor 22, and freezer compartment temperature sensor 32. Controller 50 is programmed or otherwise configured for turning compressor 40 on and off, for selecting operational states of valve 45, and for determining a current refrigerator system mode in response to a refrigerator compartment cooling priority and a freezer compartment cooling priority.
Refrigerator 10 may further comprise a refrigerator fan 26 coupled to controller 50 for moving air past refrigerator evaporator 24 into refrigerator compartment 20, where controller 50 turns refrigerator fan 26 on and off. As described further below, the refrigerator fan on time is extended at the end of each refrigerator cooling cycle, and is turned off when the actual refrigerator evaporator temperature is getting closer to the actual refrigerator compartment temperature. The refrigerator fan extension helps to continue cooling the refrigerator compartment and also helps to defrost the refrigerator evaporator without a heater. Refrigerator 10 may also further comprise a freezer fan 36 coupled to controller 50 for moving air past freezer evaporator 34 into freezer compartment 30, where controller 50 turns freezer fan 36 on and off.
A refrigerator evaporator temperature sensor 28 may be provided on or at refrigerator evaporator 24 so as to sense the temperature thereof and provide the sensed temperature to controller 50. Similarly, a freezer evaporator temperature sensor 38 may be provided on or at freezer evaporator 34 so as to sense the temperature thereof and provide the sensed temperature to controller 50. Controller 50 may use these temperature readings to control fans 26 and 36 as described further below.
Refrigerator 10 may additionally include a condenser 42 and a drier 44 fluidly connected between compressor 40 and valve 45. A check valve 48 may be provided between the output line of freezer evaporator 34 and compressor 40 so as to prevent backflow of refrigerant to freezer evaporator 34.
Lastly, refrigerator 10 may include a user interface 55 coupled to controller 50 for allowing a user to manually set a desired refrigerator compartment temperature, and a desired freezer compartment temperature. User interface 55 may optionally include door open sensors for both refrigerator compartment 20 and freezer compartment 30.
Valve 45 is preferably a three-way valve, but may consist of two or more two-way valves. Valve 45 is fluidly coupled to refrigerator evaporator 24 via a first capillary tube 47 and is coupled to freezer evaporator 34 through a second capillary tube 49. Valve 45 may have four different positions: (1) open to refrigerator evaporator 24 only (when controller 50 determines that the variables C2_VALVE=OPEN and C1_VALVE=CLOSE); (2) open to freezer evaporator 34 only (when controller 50 determines that the variables C1_VALVE=OPEN and C2_VALVE=CLOSE); (3) open to both refrigerator evaporator 24 and freezer evaporator 34 (when controller 50 determines that the variables C1_VALVE=OPEN and C2_VALVE=OPEN); and (4) closed to both refrigerator evaporator 24 and freezer evaporator 34 (when controller 50 determines that the variables C1_VALVE=CLOSE and C2_VALVE=CLOSE).
Having generally described the structure of refrigerator 10, a method for controlling refrigerator 10 is now described. The method is generally executed by controller 50, which executes an algorithm in order to control the operation of valve 45, compressor 40, refrigerator fan 26, and freezer fan 36 in response to various inputs from user interface 55, RC temperature sensor 22, FC temperature sensor 32, refrigerator evaporator temperature sensor 28, and freezer evaporator temperature sensor 38. The method generally may comprise the steps of: (a) determining the 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; (b) determining the 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; (c) 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 nor freezer compartments is cooled; and (d) 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. The freezer hysteresis may be different from the refrigerator hysteresis, and is preferably greater than the refrigerator hysteresis. However, this is not a necessary condition.
The refrigerator system mode may be set to satisfied mode when both the refrigerator compartment cooling priority and the freezer compartment cooling priority are in the satisfied priority levels. The refrigerator system mode may be set to pull-down mode when both the refrigerator compartment cooling priority and the freezer compartment cooling priority are in the high priority levels.
In general, and with some exceptions explained below, 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. In general, and with some exceptions explained below, the refrigerator system mode may be 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. The refrigerator compartment cooling priority may be 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. The freezer compartment cooling priority may be 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.
Controller 50 may determine that the refrigerator compartment cooling priority should 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. The freezer compartment cooling priority may be 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. The freezer compartment high priority constant may be the same as or different from the refrigerator compartment high priority constant.
Controller 50 may determine that the refrigerator compartment cooling priority should 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. The freezer compartment cooling priority may be 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. The freezer and refrigerator compartment medium priority constants can be different or the same.
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. 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. The freezer and refrigerator compartment medium priority constants can be different or the same.
As explained further below, the embodiment disclosed herein allows the ON/OFF cycles of compressor 40 to be reduced which lowers power consumption. The values of the hysteresis and medium and high priority constants may be independent for the freezer and refrigerator compartments and may be optimized to minimize the ON/OFF cycles of compressor 40.
Having generally described the operation of controller 50, a more specific example of operation is described below with respect to
In this example, various parameters and variables are used by the algorithm executed by controller 50. Parameters are constants that may be stored in non-volatile memory (if available) or in program memory. Parameters may be used to set values for key parts of an algorithm (especially those that are difficult to specify without performance evaluation or are model specific). These variables may be easily modified for development of algorithms and calibration of product performance. A list of the parameters and some exemplary default values, ranges, resolutions and units are provided in Table 3 appearing at the end of this example. A list of the variables and some exemplary default values, ranges, resolutions and units are provided in Table 4 appearing at the end of this example. The parameters and variables in Tables 3 and 4 are just for reference. Each application may have its own default values for parameters and variables.
As shown in
Receive opcode “set Temp Control Enable (TEMP_CONTROL_ENABLE==DISABLED)”
Controller 50 transitions from the Temperature Controller Disabled state 102 to the Temperature Controller Enabled and Locked state 100 when the following criterion of Transition 2 is met:
Receive opcode “set Temp Control Enable (TEMP_CONTROL_ENABLE==ENABLED)” OR receive opcode “set Temp Control Enable (TEMP_CONTROL_ENABLE==LOCKED)”
When in the Temperature Controller Disabled state 102, controller 50 performs the functions described below and shown in
It should be noted that for purposes of this example, any reference to “C1” refers to variables or constants associated with freezer compartment 30 and any reference to “C2” refers to variables or constants associated with refrigerator compartment 20. It will be appreciated however that “C1” and “C2” may instead refer to any two compartments of a refrigerator. The references to the freezer and refrigerator compartments are made to assist in the understanding of this example relative to the most common commercial units that include a refrigerator compartment and a freezer compartment. Further, this example may be implemented in side-by-side, top mount, and bottom mount refrigerators.
Controller 50 transitions from the No Error sub-state 200 to the Defrost Preparation sub-state 400 when the criterion of the following Transition 5 is met:
Controller 50 transitions from the Defrost Preparation sub-state 400 to the No Error sub-state 200 when the criteria of the following Transition 6 are met:
(DEFROST_STATE==MONITOR AND THERM_ERROR==NO_ERROR AND DEFROST_DELAY_TIMER timeout)
Controller 50 transitions from the Sensor Error sub-state 300 to the Defrost Preparation sub-state 400 when the criterion of the following Transition 7 is met:
Controller 50 transitions from the Defrost Preparation sub-state 400 to the Sensor Error sub-state 300 when the criteria of the following Transition 6 are met:
(DEFROST_STATE==MONITOR AND THERM_ERROR==C1_ERROR AND DEFROST_DELAY_TIMER timeout) OR (DEFROST_STATE==MONITOR AND THERM_ERROR==C2_ERROR AND DEFROST_DELAY_TIMER timeout)
As described further below, while in the No Error sub-state 200, controller 50 determines a current refrigerator mode in
When in the No Error sub-state 200, controller 50 determines which cooling priority to assign to the C1 compartment (e.g., freezer compartment 30) and the C2 compartment (e.g., refrigerator compartment 20) based on actual compartment temperatures (as sensed by sensors 22 and 32, set points, hysteresis and temperature constants associated with each compartment and determines a current refrigerator mode so as to decide which compartment(s) will be cooled and in what order. The priority calculus is executed every 1 minute and uses as reference the difference (Delta Temperature) between the actual temperature of the compartment (C#_ACTUAL_TEMP) and the control point (C#_TEMP) associated with the compartment (C#). Note that the designation C# refers to a generic compartment that may be either of the C1 or C2 compartments.
Based on Delta Temperature, hysteresis (C#_HYSTERESIS) and the priority calculation parameters (C#_TEMP_HIGH_PRIORITY_CONSTANT and C#_TEMP_MEDIUM_PRIORITY_CONSTANT), controller 50 assigns a priority for each compartment (C#) as set forth in Table 1 below.
The refrigerator compartment cooling priority (C2_PRIORITY) is thus be determined to be in a satisfied priority level (C2_PRIORITY=0) when the actual refrigerator compartment temperature (C2_ACTUAL_TEMP) minus the desired refrigerator compartment temperature (C2_TEMP) is less than or equal to the refrigerator hysteresis (C2_HYSTERESIS). The freezer compartment cooling priority (C1_PRIORITY) is determined to be in a satisfied priority level (C1_PRIORITY=0) when the actual freezer compartment temperature (C1_ACTUAL_TEMP) minus the desired freezer compartment temperature (C1_TEMP) is less than or equal to the freezer hysteresis (C1_HYSTERESIS).
The freezer hysteresis, refrigerator hysteresis, the freezer and refrigerator compartment high priority constant and medium priority constant are selected based on the market preference, freezer and refrigerator storage volume and product heat gain volume for the best performance and energy consumption. These parameters may all be stored in memory of the user interface so as to be introduced to the refrigerator as a parameter set suitable for the refrigerator characteristics and the particular market and to which the particular model is to be shipped. Such markets may vary considerably, particularly depending upon the country in which the model will be sold.
Controller 50 determines that the refrigerator compartment cooling priority is in a high priority level (C2_PRIORITY=3) when the actual refrigerator compartment temperature (C2_ACTUAL_TEMP) minus the desired refrigerator compartment temperature (C2_TEMP) is greater than or equal to a sum of a refrigerator compartment high priority constant (C2_TEMP_HIGH_PRIORITY_CONSTANT) and the refrigerator hysteresis (C2_HYSTERESIS).
The freezer compartment cooling priority is determined to be in a high priority level (C1_PRIORITY=3) when the actual freezer compartment temperature (C1_ACTUAL_TEMP) minus the desired freezer refrigerator compartment temperature (C1_TEMP) is greater than or equal to a sum of a freezer compartment high priority constant (C1_TEMP_HIGH_PRIORITY_CONSTANT) and the freezer hysteresis (C1_HYSTERESIS).
Controller 50 determines that the refrigerator compartment cooling priority is in a medium priority level (C2_PRIORITY=2) when the actual refrigerator compartment temperature (C2_ACTUAL_TEMP) minus the desired refrigerator compartment temperature (C2_TEMP) is: (1) greater than a sum of the refrigerator compartment medium priority constant (C2_TEMP_MEDIUM_PRIORITY_CONSTANT) and the refrigerator hysteresis (C2_HYSTERESIS), and (2) less than or equal to a sum of the refrigerator compartment high priority constant (C2_TEMP_HIGH_PRIORITY_CONSTANT) and the refrigerator hysteresis (C2_HYSTERESIS).
The freezer compartment cooling priority is determined to be in a medium priority level (C1_PRIORITY=2) when the actual freezer compartment temperature (C1_ACTUAL_TEMP) minus the desired freezer refrigerator compartment temperature (C1_TEMP) is: (1) greater than a sum of a freezer compartment medium priority constant (C1_TEMP_MEDIUM_PRIORITY_CONSTANT) and the freezer hysteresis (C1_HYSTERESIS), and (2) less than or equal to a sum of a freezer compartment high priority constant (C1_TEMP_HIGH_PRIORITY_CONSTANT) and the freezer hysteresis (C1_HYSTERESIS). The freezer and refrigerator compartment medium priority constants can be different or the same.
The refrigerator compartment cooling priority is determined to be in a low priority level (C2_PRIORITY=1) when the actual refrigerator compartment temperature (C2_ACTUAL_TEMP) minus the desired refrigerator compartment temperature (C2_TEMP) is: (1) greater than the refrigerator hysteresis (C2_HYSTERESIS), and (2) less than or equal to a sum of a refrigerator compartment medium priority constant (C2_TEMP_MEDIUM_PRIORITY_CONSTANT) and the refrigerator hysteresis (C2_HYSTERESIS).
The freezer compartment cooling priority is determined to be in a low priority level (C1_PRIORITY=1) when the actual freezer compartment temperature (C1_ACTUAL_TEMP) minus the desired freezer refrigerator compartment temperature (C1_TEMP) is: (1) greater than the freezer hysteresis (C1_HYSTERESIS), and (2) less than or equal to a sum of a freezer compartment medium priority constant (C1_TEMP_MEDIUM_PRIORITY_CONSTANT) and the freezer hysteresis (C1_HYSTERESIS).
Using the default values in Table 3 for the parameters used to calculate the compartment priorities, namely:
C1_TEMP=−18° C.,
C1_HYSTERESIS=2° C.,
C1_TEMP_MEDIUM_PRIORITY_CONSTANT=4° C.,
C1_TEMP_HIGH_PRIORITY_CONSTANT=5° C.,
C2_TEMP=3° C.,
C2_HYSTERESIS=1° C.,
C2_TEMP_MEDIUM_PRIORITY_CONSTANT=1° C., and
C2_TEMP_HIGH_PRIORITY_CONSTANT=2° C.,
the following priorities in Table 2 would be established:
Thus, with these exemplary parameter default values, the refrigerator compartment is given a high priority at a much lower delta temperature than is the freezer compartment, which as explained further below, tends to more often give cooling priority to the refrigerator compartment over the freezer compartment.
As described further below and shown in
Whenever the refrigerator is plugged in or after a power outage, controller 50 initializes valve 45 (block 202,
((C1_PRIORITY<3) OR (C2_PRIORITY<3)) AND ((C1_PRIORITY>0) OR (C2_PRIORITY>0)) AND ((C1_PRIORITY<C2_PRIORITY) OR (C2_ACTUAL_TEMP>=C2_TEMP−C2_HYSTERESIS))
Controller 50 initially selects the pull-down mode 210 if Transition 9 is true, the C1 cooling mode 230 if Transition 10 is true, the C2 cooling mode 230 if Transition 11 is true, and the satisfied mode if Transition 12 is true. Only one of Transitions 9-12 may be true.
After selecting an initial mode per
[(C1_PRIORITY==3) OR {((C1_PRIORITY>C2_PRIORITY) OR (C1_ACTUAL_TEMP>=C1_TEMP+C1_HYSTERESIS/2)) AND (C2_ACTUAL_TEMP<C2_TEMP−C2_HYSTERESIS)}]
From the above and
From the above, it will also be apparent that controller 50 will generally select the pull-down mode 210 whenever the cooling priorities for both compartments are high and will remain in the pull-down mode until one or both of the cooling priorities is no longer high. In this event, controller 50 will transition from the pull-down mode 210 to C1 cooling mode 230 if the cooling priority of the freezer (C1_PRIORITY) is equal to or greater than that of the refrigerator (C2_PRIORITY), otherwise it will transition from the pull-down mode 210 to C2 cooling mode 270 if the cooling priority of the freezer (C1_PRIORITY) is less than that of the refrigerator (C2_PRIORITY). The other transitions between states are apparent from
Having described how controller 50 determines the cooling priorities of the refrigerator and freezer compartments 20 and 30, and how controller determines a current refrigerator mode from the satisfied mode 204, the pull-down mode 210, the freezer (C1) cooling mode 230, and the refrigerator (C2) cooling mode 270, the controller functions performed in each of these modes is now described with reference to
PROTECTION_OFF_TIME timeout
(C1_PRIORITY==3) AND (C2_PRIORITY==3) AND PULL_DOWN_COMP_TIME is expired
(C1_PRIORITY==3) AND (C2_PRIORITY==3) AND PULL_DOWN_COMP_TIME is expired
Pull Down Pump Out function 212 is executed if PUMP_OUT_FLAG==ON. If executed, controller 50 controls valve 45 by closing it to both compartments and turns on compressor 40 in order to allow refrigerant gas return to the evaporators.
Pre-C2 Pull Down function 214 is executed if PUMP_OUT_FLAG==OFF. If executed, controller 50 turns on compressor 40, controls valve 45 by opening it to the refrigerator (C2) compartment, and after a specified delay period, turns refrigerator fan 26 on at a 100% duty cycle in order to prepare the loads to cool the refrigerator (C2) compartment. Provided C2_PUMP_OUT_TIME>PULL_DOWN_REFRNT_RTRN, Pre-C2 Pull Down function 214 is also executed following Pull Down Pump Out function 212 and function 216 in which the C2_PUMP_OUT_TIME timer is restarted following a PROTECTION_OFF_TIME timeout after function 212 is executed.
C2 Pull Down function 218 is the actual cooling of the refrigerator (C2) compartment. After PULL_DOWN_COMP_TIME it will wait for a refrigerator fan extend period before turning off refrigerator fan 26, if the product needs to switch to cool the freezer compartment or go to the satisfied mode, depending on the priorities for each compartment. More specifically, if either compartment priority is no longer at the high priority level, function 220 is performed whereby the PUMP_OUT_FLAG is set to OFF before moving to a different mode and its associated functions. If the priorities of both compartments are still high (Condition 6), controller 50 executes the Pre-C1 Pull Down function 222 whereby the loads are prepared to cool the freezer (C1) compartment.
When executing the Pre-C1 Pull Down function 222, controller 50 turns on freezer fan 36, closes valve 45 to the refrigerator compartment and opens it to the freezer compartment while keeping compressor 40 on. Thereafter, controller 50 executes the C1 Pull Down function 224 which is the actual cooling of the freezer (C1) compartment. After PULL_DOWN_COMP_TIME it will switch to another state, depending on the priorities for each compartment. More specifically, if either compartment priority is no longer at the high priority level, function 226 is performed whereby the PUMP_OUT_FLAG is set to ON before moving to a different mode and its associated functions. If the priorities of both compartments are still high (Condition 8), controller 50 returns to the Pull Down Pump Out function 212. The functions of
If controller 50 required to leave Pull Down Mode 210 for another mode, freezer fan 36 (C1_Fan) or refrigerator fan 26 (C2_Fan) will remain on until PULL_DOWN_C1_FAN_EXTENDED or PULL_DOWN_C2_FAN_EXTENDED is expired, respectively.
If in block 234, controller 50 determines that compressor 40 is OFF, it determines in block 236 whether valve 45 is open to both evaporators 24 and 34 or only one of the evaporators. If valve 45 is open to both evaporators, controller 50 executes block 250 whereby valve 45 is closed to refrigerator evaporator 24 and compressor 40 is turned on. Then, after a longer delay, freezer fan 36 is turned on in block 252 before proceeding to the aforementioned block 242. If valve 45 is open to only one of the evaporators, controller 50 executes block 254 whereby valve 45 is closed to refrigerator evaporator 24 and opened to freezer evaporator 34 and compressor 40 is turned on. Then, controller 50 executes the aforementioned blocks 248 and 242.
Referring back to
If one of Transitions 16, 20, or 23 force controller 50 to leave the C1 cooling mode 230, controller first closes valve 45 to freezer evaporator 34, waits for a fan delay period and turns off freezer fan 36 (C1_FAN), and then sets PUMP_OUT_FLAG to ON in block 256.
When controller 50 goes from C1 cooling mode 230 to another mode the freezer (C1) fan 36 will remain ON until C1_COOLING_C1_FAN_EXTEND is expired. In order to avoid the system to switch to another cooling mode at beginning of C1 cooling mode 230, controller 50 shall stay in C1 cooling Mode for a minimum amount of time (C1_ON_COOLING TIME), even if the C2_PRIORITY is higher than C1_PRIORITY.
As shown, the process begins with a determination as to whether the PUMP_OUT_FLAG is ON or OFF. If it is ON, controller 50 proceeds to the C2 Pump Out function 272, and if it is OFF, controller 50 proceeds to the C2 Pre-Cooling function 274.
In the C2 Pump Out function 272, controller 50 closes valve 45 to both evaporators and turns on compressor 40 to allow refrigerant gas return to the condenser. When the compressor is prevented from being turned on by the compressor protection time, controller 50 will wait for the compressor protection time out before it restarts C2_PUMP_OUT_TIME in block 276 and proceeds to C2 Pre-Cooling function 274 when C2_PUMP_OUT_TIME is greater than C2_REFRIGERANT_RETURN_TIME.
In the C2 Pre-Cooling function 274, the loads are prepared to cool the refrigerator (C2) compartment. Specifically, the compressor is turned on, valve 45 is opened to refrigerator evaporator 34, turns refrigerator fan 26 on at 100% duty cycle after a delay, and sets C2_ON_COOLING_TIMER to C2_COOLING_TIME.
C2 Cooling function 278 is executed after C2 Pre-Cooling function 274. During C2 Cooling function 278, the temperature in refrigerator compartment 20 gets colder until one of Transitions 18, 22, or 24 force controller 50 to leave the C2 cooling mode 270 based on the priority status of both compartments. If transitioning conditions are not met, controller 50 will add an extra cooling time to C2_ON_COOLING_TIMER to allow the temperature in refrigerator compartment 20 to continue to drop in the C2 Extra Cooling function 280.
When the system goes from C2 cooling mode 270 to another mode, refrigerator fan 26 (C2 fan) will remain on until C2_COOLING_C2_FAN_EXTEND is expired or C2_ACTUAL_TEMP−C2_EVAP_ACTUAL_TEMP<C2_FAN_OFF_DELTA_T as shown in block 278.
As shown in
As shown in
As shown in
As mentioned above, refrigerator evaporator temperature sensor 28 (C2 Evap Sensor) is used to control refrigerator fan 26 (C2 Evap fan) extension. If refrigerator evaporator temperature sensor 28 (C2 Evap Sensor) is in error, control refrigerator fan 26 (C2 Evap fan) extension will be executed until C2_COOLING_C2_FAN_EXTEND is elapsed.
In the OK to Defrost sub-state 402, which is used to determine when the refrigerator is ready to defrost, controller 50 opens valve 45 to freezer evaporator 34, turns freezer fan 36 off, opens valve 45 to refrigerator evaporator 24, turns refrigerator fan 26 off, and turns compressor 40 off.
As mentioned above, Tables 3 and 4 below are provided to give some exemplary values of the various parameters and variables used in the above example. These parameters and variables are not limited to the values provided and may be varied to achieve optimal performance, and more specifically to minimize power consumption.
The above description is considered that of the preferred embodiments only. Modifications of the invention will occur to those skilled in the art and to those who make or use the invention. Therefore, it is understood that the embodiments shown in the drawings and described above are merely for illustrative purposes and not intended to limit the scope of the invention, which is defined by the following claims as interpreted according to the principles of patent law, including the doctrine of equivalents.
