Abstract:
In one aspect, the present invention is directed to a refrigerator that includes an icemaker that is operable to .form ice at a first rate during normal operation, and at a second, faster, rate upon demand for additional ice. More specifically, and in an exemplary embodiment, the refrigerator includes a fresh food compartment and a freezer compartment. The refrigerator also includes a refrigeration circuit having a compressor, a condenser, and an evaporator connected in series. A condenser fan is positioned to blow air over the condenser and an evaporator fan is positioned to blow air over the evaporator. The icemaker is located in the freezer compartment and positioned so that the evaporator blows air over an ice mold of the icemaker. The refrigerator also includes a control coupled to a user interface and to the evaporator fan. The control includes a processor, and the processor is programmed to control energization of the evaporator fan upon selection of an ice rate booster mode at the user interface. By operating the evaporator fan to blow air over the ice mold upon command at the user interface, ice can be formed at a faster rate to satisfy the ice needs of the user. Such operation is more responsive to user needs than systems in which the ice forming rate is not responsive to user inputs.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to refrigerators, and more particularly, to ice making function in such refrigerators. 
     Some known refrigerators include a fresh food compartment and a freezer compartment. Such a refrigerator also typically includes a refrigeration circuit including a compressor, evaporator, and condenser connected in series. An evaporator fan is provided to blow air over the evaporator, and a condenser fan is provided to blow air over the condenser. 
     In operation, when an upper temperature limit is reached in the freezer compartment, the compressor, evaporator fan, and condenser fan are energized. Once the temperature in the freezer compartment reaches a lower temperature limit, the compressor, evaporator fan, and condenser fan are de-energized. 
     An icemaker may be located in the freezer compartment and operable to make ice cubes. A primary mode of heat transfer for making ice is convection. Specifically, by blowing cold air over an icemaker mold body, heat is removed from water in the mold body. As a result, ice is formed in the mold. Typically, the cold air blown over the icemaker mold body is first blown over the evaporator and then over the mold body by the evaporator fan. 
     Heat transferred in a given fluid due to convection can be increased or decreased by changing a film coefficient. The film coefficient is dependent on fluid velocity and temperature. With a high velocity and low temperature, the film coefficient is high, which promotes heat transfer and increasing the ice making rate. Therefore, when the refrigeration system is activated, i.e., when the compressor, evaporator fan, and condenser fan are on, ice is made at a quick rate as compared to when the refrigeration is inactivated. Specifically, the air is not as cold and the air velocity is lower when the system is inactivated as compared to when the system is activated. 
     User demand for ice, however, is not related to the state of the refrigeration system. Specifically, a user may have a high demand for ice at a time in which the system in inactivated or may have no need for ice at a time at which the system is activated. Therefore, ice may be depleted during a period of high demand for ice by a user and the refrigeration system may not necessarily respond to the user demand by making ice more quickly. 
     BRIEF SUMMARY OF THE INVENTION 
     In one aspect, the present invention is directed to a refrigerator that includes a refrigerator compartment that is operable to form ice at a first rate during normal operation, and at a second, faster, rate upon demand for additional ice. More specifically, and in an exemplary embodiment, the refrigerator includes a fresh food compartment and a freezer compartment. The refrigerator also includes a refrigeration circuit having a compressor, a condenser, and an evaporator connected in series. A condenser fan is positioned to blow air over the condenser and an evaporator fan is positioned to blow air over the evaporator. The icemaker is located in the freezer compartment and positioned so that the evaporator blows air over an ice mold of the icemaker. 
     The refrigerator also includes a control coupled to a user interface and to the evaporator fan. The control includes a processor, and the processor is programmed to control energization of the evaporator fan upon selection of an ice rate booster mode at the user interface. By operating the evaporator fan and/or freezer compartment temperature to blow air over the ice mold upon command at the user interface, ice can be formed at a faster rate to satisfy the ice needs of the user. Such operation is more responsive to user needs than systems in which the ice forming rate is not responsive to user inputs. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a side-by-side type refrigerator; 
     FIG. 2 is a block diagram of a refrigerator controller in accordance with one embodiment of the present invention; 
     FIG. 3 is a block diagram of the main control board shown in FIG. 1; 
     FIG. 4 is a block diagram of the main control board shown in FIG. 1; 
     FIG. 5 is a schematic illustration of a refrigeration compartment including an icemaker; and 
     FIG. 6 is a flow chart illustrating control steps executed when in an ice booster mode. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Ice formation systems and methods are described herein in the context of residential, or domestic, refrigerators. The ice formation systems and methods can, however, be utilized in connection with commercial refrigerators as well as in standalone ice makers, i.e., ice makers that are not part of a larger freezer compartment or refrigerator. Therefore, the ice formation systems and methods described herein are not limited to use in connection with only ice makers utilized in residential refrigerators, and can be utilized in connection with ice makers in many other environments. In addition, ice formation systems and methods are sometimes described herein in the context of a side-by-side type refrigerator. Such systems and methods are not, however, limited to use in connection with side-by-side type refrigerators and can be used with other types of refrigerators, e.g., a top mount type refrigerator. 
     FIG. 1 illustrates a side-by-side refrigerator  100  including a fresh food storage compartment  102  and freezer storage compartment  104 . Freezer compartment  104  and fresh food compartment  102  are arranged side-by-side. A side-by-side refrigerator such as refrigerator  100  is commercially available from General Electric Company, Appliance Park, Louisville, Ky.  40225 . 
     Refrigerator  100  includes an outer case  106  and inner liners  108  and  110 . A space between case  106  and liners  108  and  110 , and between liners  108  and  110 , is filled with foamed-in-place insulation. Outer case  106  normally is formed by folding a sheet of a suitable material, such as pre-painted steel, into an inverted U-shape to form top and side walls of case. A bottom wall of case  106  normally is formed separately and attached to the case side walls and to a bottom frame that provides support for refrigerator  100 . Inner liners  108  and  110  are molded from a suitable plastic material to form freezer compartment  104  and fresh food compartment  102 , respectively. Alternatively, liners  108 ,  110  may be formed by bending and welding a sheet of a suitable metal, such as steel. The illustrative embodiment includes two separate liners  108 ,  110  as it is a relatively large capacity unit and separate liners add strength and are easier to maintain within manufacturing tolerances. In smaller refrigerators, a single liner is formed and a mullion spans between opposite sides of the liner to divide it into a freezer compartment and a fresh food compartment. 
     A breaker strip  112  extends between a case front flange and outer front edges of liners. Breaker strip  112  is formed from a suitable resilient material, such as an extruded acrylo-butadiene-syrene based material (commonly referred to as ABS). 
     The insulation in the space between liners  108 ,  110  is covered by another strip of suitable resilient material, which also commonly is referred to as a mullion  114 . Mullion  114  also preferably is formed of an extruded ABS material. It will be understood that in a refrigerator with separate mullion dividing a unitary liner into a freezer and a fresh food compartment, a front face member of mullion corresponds to mullion  114 . Breaker strip  112  and mullion  114  form a front face, and extend completely around inner peripheral edges of case  106  and vertically between liners  108 ,  110 . Mullion  114 , insulation between compartments, and a spaced wall of liners separating compartments, sometimes are collectively referred to herein as a center mullion wall  116 . 
     Shelves  118  and slide-out drawers  120  normally are provided in fresh food compartment  102  to support items being stored therein. A bottom drawer or pan  122  partly forms a quick chill and thaw system (not shown in FIG. 1) described in detail below and selectively controlled, together with other refrigerator features, by a microprocessor (not shown in FIG. 1) according to user preference via manipulation of a control interface  124  mounted in an upper region of fresh food storage compartment  102  and coupled to the microprocessor. A shelf  126  and wire baskets  128  are also provided in freezer compartment  104 . In addition, an icemaker  130  is provided in freezer compartment  104 . 
     A freezer door  132  and a fresh food door  134  close access openings to fresh food and freezer compartments  102 ,  104 , respectively. Each door  132 ,  134  is mounted by a top hinge  136  and a bottom hinge (not shown) to rotate about its outer vertical edge between an open position, as shown in FIG. 1, and a closed position (not shown) closing the associated storage compartment. Freezer door  132  includes a plurality of storage shelves  138  and a sealing gasket  140 , and fresh food door  134  also includes a plurality of storage shelves  142  and a sealing gasket  144 . 
     FIG. 2 illustrates a controller  200  that can be used, for example, in refrigerators, freezers and combinations thereof, such as, for example side-by-side (S×S) refrigerator  100  (shown in FIG.  1 ). The present systems and methods are not limited to practice with any one specific controller, and controller  200  is illustrated and described herein as one example of a controller which can be configured to operate in accordance with the present invention. 
     Controller  200  includes a diagnostic port  202  and a human machine interface (HMI) board  204  coupled to a main control board  206  by an asynchronous interprocessor communications bus  208 . An analog to digital converter (“A/D converter”)  210  is coupled to main control board  206 . Converter  210  converts analog signals from a plurality of sensors  212  including one or more fresh food compartment temperature sensors, feature pan temperature sensors, freezer temperature sensors, external temperature sensors, and evaporator temperature sensors into digital signals for processing by main control board  206 . 
     Digital input and relay outputs  214  are supplied to and received from main control board  206 . Such inputs and outputs  214  correspond to, but are not limited to variables  216  such as a condenser fan speed, an evaporator fan speed, a crusher solenoid, an auger motor, personality inputs, a water dispenser valve, encoders for set points, a compressor control, a defrost heater, a door detector, a mullion damper, feature pan air handler dampers, and a feature pan heater. Main control board  206  also is coupled to a pulse width modulator  218  for controlling variables  220  such as the operating speed of a condenser fan, a fresh food compartment fan, an evaporator fan, and a quick chill system feature pan fan. 
     FIGS. 3 and 4 are more detailed block diagrams of main control board  206 . As shown in FIGS. 3 and 4, main control board  206  includes a processor  300 . Processor  300  performs temperature adjustments/dispenser communication, AC device control, signal conditioning, microprocessor hardware watchdog, and EEPROM read/write functions. In addition, processor  300  executes many control algorithms including sealed system control, evaporator fan control, defrost control, feature pan control, fresh food fan control, stepper motor damper control, water valve control, auger motor control, cube/crush solenoid control, timer control, and self-test operations. 
     Processor  300  is coupled to a power supply  302  which receives an AC power signal from a line conditioning unit  304 . Line conditioning unit  304  filters a line voltage which is, for example, a 90-265 Volts AC, 50/60 Hz signal. Processor  300  also is coupled to an EEPROM  306  and a clock circuit  308 . 
     A door switch input sensor  310  is coupled to fresh food and freezer door switches  312 , and senses a door switch state. A signal is supplied from door switch input sensor  310  to processor  300 , in digital form, indicative of the door switch state. Fresh food thermistors  314 , a freezer thermistor  316 , at least one evaporator thermistor  318 , a feature pan thermistor  320 , and an ambient thermistor  322  are coupled to processor  300  via a sensor signal conditioner  324 . Conditioner  324  receives a multiplex control signal from processor  300  and provides analog signals to processor  300  representative of the respective sensed temperatures. Processor  300  also is coupled to a dispenser board  326  and a temperature adjustment board  328  via a serial communications link  330 . 
     Processor  300  provides control outputs to a DC fan motor control  332 , a DC stepper motor control  334 , a DC motor control  336 , and a relay watchdog  338 . Watchdog  338  is coupled to an AC device controller  340  that provides power to AC loads, such as to water valve  342 , cube/crush solenoid  344 , a compressor  346 , auger motor  348 , a feature pan heater  350 , and defrost heater  352 . DC fan motor control  332  is coupled to evaporator fan  354 , condenser fan  356 , fresh food fan  358 , and feature pan fan  360 . DC stepper motor control  334  is coupled to mullion damper  362 , and DC motor control  336  is coupled to feature pan dampers  364 ,  366 . 
     Processor  300  includes logic to use the following inputs to make control decisions: 
     Freezer Door State—Light Switch Detection Using Optoisolators, 
     Fresh Food Door State—Light Switch Detection Using Optoisolators, 
     Freezer Compartment Temperature—Thermistor, 
     Evaporator Temperature—Thermistor, 
     Upper Compartment Temperature in FF—Thermistor, 
     Lower Compartment Temperature in FF—Thermistor, 
     Zone (Feature Pan) Compartment Temperature—Thermistor, 
     Compressor On Time, 
     Time to Complete a Defrost, 
     User Desired Set Points via Electronic Keyboard and Display or Encoders, 
     User Dispenser Keys, 
     Cup Switch on Dispenser, and 
     Data Communications Inputs. 
     The electronic controls activate the following loads to control the refrigerator: 
     Multi-speed or variable speed (via PWM) fresh food fan, 
     Multi-speed (via PWM) evaporator fan, 
     Multi-speed (via PWM) condenser fan, 
     Single-speed zone (Special Pan) fan, 
     Compressor Relay, 
     Defrost Relay, 
     Auger motor Relay, 
     Water valve Relay, 
     Crusher solenoid Relay, 
     Drip pan heater Relay, 
     Zonal (Special Pan) heater Relay, 
     Mullion Damper Stepper Motor IC, 
     Two DC Zonal (Special Pan) Damper H-Bridges, and 
     Data Communications Outputs. 
     The electronic control system performs the following functions: compressor control, freezer temperature control, fresh food temperature control, multi speed control capable for the condenser fan, multi speed control capable for the evaporator fan (closed loop), multi speed control capable for the fresh food fan, defrost control, dispenser control, feature pan control (defrost, chill), and user interface functions. These functions are performed under the control of firmware implemented as small independent state machines. 
     In addition to the foregoing, processor  300  is configured to control evaporator fan  354  under certain conditions to facilitate the formation of ice at an increased, or boosted, rate of a refrigeration compartment  380 , such as a freezer compartment, including an exemplary icemaker  382  as shown in FIG. 5. A fan  384  is located in compartment  380  to blow cold air over icemaker  382  to facilitate a rate of ice formation. Icemaker includes an ice mold  386  that receives water for forming ice cubes or blocks, and a bucket  388  for storage of ice cubes or blocks once they are formed and released from ice mold  386 . In one embodiment, ice is dispensed from bucket  388  through a dispensing duct  390 . In alternative embodiments, other known types of icemakers are employed. In a further embodiment, fan  384  is evaporator fan  354 , while in still further embodiments, fan  384  is an auxiliary fan located in refrigeration compartment  380  to boost an ice formation rate. 
     More specifically, and referring to FIG. 6, in an ice rate booster mode  400 , processor  300  checks the freezer temperature (TEMP FZ ) to determine whether the freezer temperature is greater than or equal to a pre-set temperature (X)  402 . If no, the processor  300  continues performing the check  402 . If yes, then processor  300  causes the compressor, condenser fan, and evaporator fan to be energized  404 . Then, processor  300  checks whether the freezer temperature is less than or equal to a pre-set temperature (Y)  406 . If no, then the compressor, condenser fan, and evaporator fan remain energized  404  and another check is  406  is performed. If yes, then only the compressor and the condenser fan are de-energized  408 . That is, the evaporator fan remains energized to blow cold air over the ice maker. 
     In one embodiment, the evaporator fan is energized for an entire period between refrigeration cycles, i.e., when the compressor and condenser fan are de-energized, to facilitate ice making. In an alternative embodiment, the evaporator fan is energized for part of the period between refrigeration cycles, and de-energized for the remaining period between refrigeration cycles. After completion of a refrigeration cycle when the compressor and condenser fan are de-energized, operations then return to step  302  to check whether the freezer temperature has risen to or above pre-set temperature (X). Formation of ice in ice booster mode is therefore governed by the freezer temperature and air flow over the ice maker. By increasing air flow at a given temperature, or by lowering air temperature at a given air flow, or by combinations of adjusted temperature and air flow, rate of ice formation can be affected considerably. 
     As explained above, in the ice booster mode, the evaporator fan is maintained on so that the fan continues to blow cold air over the evaporator and over the ice mold of the ice maker. Such continuous flow of air over the mold facilitates formation of ice at a faster rate than if air was not being blown over the mold. In an alternative embodiment, an auxiliary fan is used to blow cold air over the ice mold of the ice maker, either separately or in conjunction with the evaporator fan. 
     The ice rate booster mode can be entered into in various ways. For example, the user interface could be configured to include an ice rate booster selection selectable by a user for consumer control of ice rate formation. Upon sensing selection of this option by the processor  300  (e.g., at the demand of the user and at a time selected by the user), processor  300  energizes the evaporator fan and/or adjusts freezer compartment temperature to facilitate the increased rate of ice formation. 
     In another embodiment, processor  300  can be programmed to automatically enter the ice booster mode and cause the freezer compartment to be operated at a colder temperature setting, including but not limited to a coldest possible selectable temperature when the ice rate booster mode is activated. By cooling the freezer compartment to a colder temperature, such conditions also facilitate increasing the rate of formation of ice in the icemaker as compared to when the freezer compartment is at higher temperature. Operating the freezer compartment at such colder temperature requires, of course, activating the refrigeration circuit to reduce the freezer temperature. In one embodiment, energization of the evaporator fan and fan rate is also automatically controlled when ice booster mode is activated. 
     In one embodiment, an ice level sensor (not shown) could be provided in connection with an ice container of the icemaker for automatic control of ice booster mode. Ice level sensors are well known. Once the level, or amount, of ice in the container falls below a pre-set level, then processor  300  could be programmed to automatically (i.e., without requiring any user input) enter into the ice rate booster mode. 
     In yet another embodiment, ice booster mode is implemented on a full time basis. That is, ice boosting mode is always activated. 
     As explained above, the method for controlling operation of the icemaker includes the steps of operating the freezer compartment in a first mode in which ice is made at a first rate, and in response to increased demand for ice, operating the freezer compartment in a second mode in which ice is made at a second rate, wherein the second rate is higher than the first rate. In the exemplary embodiment, the first mode is a normal operation mode wherein freezer compartment temperature is maintained at a selected temperature and the evaporator fan is energized and de-energized with the compressor and condenser fans to complete refrigeration cycles. The second mode is an ice rate booster mode wherein freezer temperature and/or operation of the evaporator fan are adjusted to produce a satisfactory ice formation rate, as described above. 
     While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.