Abstract:
An icemaker assembly includes an ice tray having an ice forming compartment, a water line configured to advance water from a water source to the ice tray, a valve operable to selectively block advancement of water through the water line while an actuation signal is generated, a control system operable to generate the actuation signal for a water advancement period, a water level detection system for determining if a level of water in the ice forming compartment is below a threshold value and generating a control signal in response thereto. The control system is further operable to alter a magnitude of the water advancement period in response to generation of the control signal. Water is initially advanced into the ice forming compartment for a first period of time during a first ice making cycle by opening the valve. If it is determined that the level of water in the ice forming compartment is below a threshold value during the first ice making cycle, a control signal is generated in response thereto and during a second ice making period the valve is opened for a second period of time in response to generation of the control signal so that water advances into the ice forming compartment of said ice tray through the valve during said second ice making cycle for a period of time that is greater than the first period of time.

Description:
CROSS REFERENCE  
       [0001]     Cross reference is made to co-pending U.S. patent application Ser. No. 10/895,665 (Attorney Docket No. 1007-0574) filed Jul. 21, 2004, entitled Method and Device for Stirring Water During Icemaking, U.S. patent application Ser. No. 10/895,792 (Attorney Docket No. 1007-0577) filed Jul. 21, 2004, entitled Method and Device for Eliminating Connecting Webs Between Ice Cubes and U.S. patent application Ser. No. 10/895,570 (Attorney Docket No. 1007-0579) filed Jul. 21, 2004, entitled Method and Device for Producing Ice Having a Harvest-facilitating Shape, which are assigned to the same assignee as the present invention, the disclosures of which are hereby incorporated by reference in their entirety. 
     
    
     BACKGROUND AND SUMMARY  
       [0002]     This invention relates to icemakers for household refrigerators and more particularly to ice makers that adjust the fill time based upon a sensed level of filling of the ice tray.  
         [0003]     Conventional ice makers typically provide an ice tray including a plurality of compartments to be filled with water which is frozen to form ice cubes. A water supply is typically in fluid communication with at least one of the compartments of the ice tray. Often weirs, slots or gaps are provided between adjacent compartments in the tray so that water may be introduced into one compartment and overflow into adjacent compartments.  
         [0004]     Typically ice makers use a timer controlled valve on the water supply to determine the level of water in the compartments. This method of controlling water level requires an initial calibration of the device to achieve the desired fill level. Often the fill level may be adjusted by the user between a minimum level wherein the valve is open for a minimum time interval and a maximum level wherein the valve is open for a maximum time interval.  
         [0005]     In some prior art devices, the timer is implemented on a disk attached to the end of a motor driven shaft of an ejector arm that rotates at a known rate. In such implementations, during an ejection cycle when the ejector arm is being rotated 360 degrees to eject the ice cubes, a contact engages a conductive strip on the disk after the ejector arm has rotated sufficiently to eject ice formed in the compartments of the tray thereby closing a circuit that opens the solenoid operated water valve. The conductive strip extends about the focus of the disk and has a length. However, the conductive strip is either non-concentrically located or varies in width so that lateral movement of the contact can cause the contact to engage and disengage the conductive strip at various points during rotation of the ejector arm. Thus, by adjusting the lateral position of the first contact, the user can control the time that the water fill valve is opened and thus adjust the level of the water in the compartments.  
         [0006]     Unfortunately, timers alone cannot guaranty consistent fill levels. Over time, water lines tend to become corroded or clogged with mineral deposits. Additionally, water pressure may vary. These factors alter the flow rate of water into the compartments and thus the fill level of the compartments. An increase in flow rate could result in an overflow of the ice-tray allowing water to flow into the freezer compartment. A decrease in flow rate could result in smaller ice cubes and insufficient ice supply.  
         [0007]     Thus, an ice maker that adapts to differing flow rates to maintain the fill level of the ice forming compartments would be appreciated.  
         [0008]     According to one aspect of the disclosure, a method of producing ice comprises the steps of opening a valve for a first period of time, determining if a level of water is below a threshold value, opening the valve for a second period of time. The opening a valve for a first period of time step occurs during a first ice making cycle so that water advances from a fluid source into at least one ice forming compartment of an ice tray through the valve. The determining if a level of water is below a threshold value step occurs in at least one ice forming compartment during the first ice making cycle. A control signal is generated in response to the determining step. The opening the valve for a second period of time occurs during a second ice making cycle in response to generation of the control signal so that water advances from a fluid source into the at least one ice forming compartment of the ice tray through the valve during the second ice making cycle. The second period of time is greater than the first period of time.  
         [0009]     According to a second aspect of the disclosure, a method of producing ice, comprises the steps of performing successive ice making cycles, determining if a size characteristic of said ice member produced during a first ice making cycle is less than a threshold value and generating a control signal in response thereto and increasing a magnitude of said water advancement period for a subsequent ice making cycle in response to generation of said control signal. Each ice making cycle includes advancing water into at least one ice forming compartment of an ice tray by opening a valve connected to a water source for a water advancement period and reducing the temperature of water within said ice tray after said water advancing step so as to cause said water located within said at least one ice forming compartment to become an ice member.  
         [0010]     According to yet another aspect of the disclosure, an icemaker assembly comprises an ice tray, a water line, a valve, a control system, and a water level detection system. The ice tray has at least one ice forming compartment. The water line is configured to advance water from a water source to the ice tray. The valve is operable to selectively block advancement of water through the water line while an actuation signal is generated. The control system is operable to generate the actuation signal for a water advancement period. The water level detection system determines if a level of water in the at least one ice forming compartment is below a threshold value and generates a control signal in response thereto. The control system is further operable to increase a magnitude of the water advancement period in response to generation of the control signal.  
         [0011]     According to still another aspect of the disclosure, an icemaker assembly comprises an ice tray, a water line, a valve, a control system and an ice size detector. The ice tray has at least one ice forming compartment. The water line is configured to advance water from a water source to the ice tray. The valve is operable to selectively block advancement of water through the water line while an actuation signal is generated. The control system is operable to generate the actuation signal for a water advancement period. The ice size detection system determines if a size characteristic of an ice member located in the at least one ice forming compartment is less than a threshold value and generates a control signal in response thereto. The control system is further operable to increase a magnitude of said water advancement period in response to generation of the control signal.  
         [0012]     Additional features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     The illustrative devices will be described hereinafter with reference to the attached drawings which are given as non-limiting examples only, in which:  
         [0014]      FIG. 1  is a perspective view of an icemaker mounted to the inside of a freezer compartment of a household side-by-side refrigerator/freezer showing an icemaker assembly including an ice tray, an ejector arm and a control box wherein a motor is mounted, a water inlet, and an ice bin;  
         [0015]      FIG. 2  is a perspective view of the icemaker assembly of  FIG. 1  removed from the freezer compartment showing a cover removed from the control box to disclose a controller implemented in part on a PCB and a motor for rotating the ejector arm, the ejector members of which are shown partially inserted into compartments of the ice tray to act as displacement members;  
         [0016]      FIG. 3  is a perspective view of the ice tray and ejector arm of the icemaker of  FIG. 2 ;  
         [0017]      FIG. 4  is a block diagram of the controller and systems of the disclosed ice maker assembly;  
         [0018]      FIG. 5  is a perspective view of the ejector arm of the ice maker assembly of  FIG. 2  showing seven ejector members mounted to a shaft configured to be rotated by the motor;  
         [0019]      FIG. 6  is a perspective view of the front portion of the ice tray and ejector arm of  FIG. 3  with parts broken away showing the overflow channels in divider walls between each adjacent crescent-shaped compartment and a displacement member disposed in the front compartment to facilitate overflow filling of the ice tray;  
         [0020]      FIG. 7  is a plan view of the ice tray of  FIG. 3  showing the configuration of the divider walls between adjacent crescent-shaped compartments;  
         [0021]      FIG. 8  is a sectional view of the ice tray taken along line  8 - 8  of  FIG. 7  which also shows a heater disposed below the ice tray;  
         [0022]      FIG. 9  is a sectional view of the ice tray and ejector arm taken through the rear compartment adjacent the rear end wall looking toward the front end wall during the fill operation showing the ejector arm positioned with an ejector member extending into the ice forming space of the compartment to act as a displacement member for displacing water that is flowing over the overflow channel;  
         [0023]      FIG. 10  is a sectional view similar to  FIG. 9  showing a front portion of the ejector member disposed in the ice forming compartment to displace less water than when the ejector member is positioned as shown in  FIG. 9  to permit larger ice cubes to be formed in the compartment,  FIG. 10  also shows one position that the ejector member may take during stirring of the water while cooling or while determining the fill level error utilizing the second embodiment of adaptively filling an ice tray;  
         [0024]      FIG. 11  is a sectional view similar to  FIG. 10  showing a rear portion of the ejector member disposed in the ice forming compartment to displace less water than when the ejector member is positioned as shown in  FIG. 9  to permit larger ice cubes to be formed in the compartment,  FIG. 11  also shows one position that the ejector member may take during stirring of the water while cooling or while determining the fill level error utilizing the second embodiment of adaptively filling an ice tray;  
         [0025]      FIG. 12  is a sectional view similar to  FIG. 9  after the ejector arm has rotated partially into the ice forming space to urge the ice cube formed in the compartment along an ejection path of motion;  
         [0026]      FIG. 13  is a sectional view similar to  FIG. 9  following removal of the ejector member from the ice forming space of the compartment to a home position prior to ice forming in the compartment showing how the water level falls below the level of the overflow channel to eliminate formation of an ice bridge between adjacent cubes;  
         [0027]      FIG. 14  is a sectional view similar to  FIG. 9  after ice has formed in the compartment and the ejector arm has been rotated to bring the front face of the ejector member into contact with the top surface of the ice cube formed accurately representing either the ejector arm touching off on the narrow side of the ice cube to determine its size for implementation of the first embodiment of adaptively filling an ice tray or the ejector arm initiating an ejection cycle;  
         [0028]      FIG. 15  is a sectional view similar to  FIG. 14  after ice has formed in the compartment and the ejector arm has been rotated to bring the rear face of the ejector member into contact with the top surface of the ice cube formed showing the ejector arm touching off on the wide side of the ice cube to determine its size for implementation of the first embodiment of adaptively filling an ice tray;  
         [0029]      FIGS. 16A  and B are a flow diagram of a method of adaptively filling an ice tray wherein the ejector members are utilized to touch off on the ice cubes formed to determine the size of the cubes;  
         [0030]      FIG. 17  is an elevation view of portions of the PCB with components removed for clarity showing a transformer, a rotary detection emitter and sensor and an ejector arm encoder face cam of the drive train for detecting the position of the ejector arm;  
         [0031]      FIG. 18  is an elevation view of the PCB of  FIG. 17  with the a rotary detection emitter and sensor and an ejector arm encoder face cam and indicia thereon shown in phantom lines;  
         [0032]      FIG. 19  is a sectional view taken along line  19 - 19  of the PCB, showing the rotary detection emitter and sensor, ejector arm encoder face cam and indicia of  FIG. 18 ;  
         [0033]      FIG. 20  is a perspective view of a portion of an ice tray, ejector arm and an alternative drum-type ejector arm encoder face cam having indicia formed as slots in a cylindrical axially extending wall;  
         [0034]      FIG. 21  is a sectional view similar to that shown in  FIG. 19  showing the alternative drum-type ejector arm encoder face cam of  FIG. 20 , a PCB and a rotary detection emitter and sensor positioned to sense the indicia;  
         [0035]      FIG. 22  is a flow diagram of a second method of adaptively filling an ice tray wherein the fill level of water in the tray is determined and the fill time is adjusted accordingly; and  
         [0036]      FIG. 23  is a flow diagram of a method of determining the fill level utilizing the ejector members to displace water to induce the water to overflow into an overflow compartment and adjusting the fill time that may be used with the method of  FIG. 22 . 
     
    
       [0037]     Corresponding reference characters indicate corresponding parts throughout the several views. Like reference characters tend to indicate like parts throughout the several views.  
       DETAILED DESCRIPTION  
       [0038]     For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and described in the following written specification. It is understood that no limitation to the scope of the invention is thereby intended. It is further understood that the present invention includes any alterations and modifications to the illustrated embodiments and includes further applications of the principles of the invention as would normally occur to one skilled in the art to which this invention pertains.  
         [0039]     As shown, for example, in  FIGS. 1-7 , an ice maker assembly  10  is incorporated in a freezer compartment  12  of a household side by side refrigerator/freezer  14 . The icemaker assembly  10  is mounted to a side wall  16  of the freezer compartment  12 . The illustrated refrigerator/freezer  14  includes through the door ice and water. To facilitate through the door delivery of ice, the illustrated ice maker assembly  10  includes an ice tray  20 , an ice ejector  22 , an ice bin  24 , an ice dispenser  26 , a water inlet  28  and a controller  30 . In the illustrated ice maker assembly  10 , the water inlet or line  28  is in fluid communication with ice tray  20  and a household water supply  18  so that water may be added to ice tray  20 . A solenoid actuated water valve  32  is disposed in the line  28  between the household water supply  18  and the tray  20  to control the flow of water into the tray  20 . Water received in tray  20  freezes and is removed from tray  20  by ejector  22 . Ice ejected from tray  20  is received in bin  24  where it is stored awaiting use. The bin  24  is formed to include a dispenser  26  from which ice is dispensed to the user. In the illustrated embodiment of ice maker assembly  10  dispenser  26  is a through the door ice dispenser.  
         [0040]     Referring now to  FIGS. 2-7 , the icemaker assembly  10  is shown removed from the freezer compartment  12  and in various states of disassembly. In the illustrated embodiment, ice tray  20  includes a plurality of compartments  66  within which ice is formed. A first compartment  66   r  is positioned adjacent to the outlet of the water line  28  and is in fluid communication with the outlet. The illustrated tray  20  is designed for overflow filling, i.e. water fills the rear compartment  66   r  to the point of overflowing and the overflow water then fills the adjacent compartment  66 .  
         [0041]     As shown, for example, in  FIGS. 3 and 7 , ice tray  20  is formed to include seven tapered crescent-shaped compartments  66 , an end water inlet ramp  68 , a side water inlet ramp  70 , ejector arm mounting features  72 , and mounting brackets  74 . Tray  20  includes a first end wall  76 , a second end wall  78 , a plurality of partitions or divider walls  80  and a plurality of floor walls  82  that cooperate to form the ice forming compartments  66 . In the illustrated embodiment, the end water inlet ramp  68  is formed in the second end wall  78  to be positioned below the water inlet  28  to facilitate filling the seven compartments  66  using the overflow method. The side water inlet ramp  70  is provided for those refrigerator/freezers  14  that position the water inlet along the mounting wall  16  of the freezer compartment  12 . Water inlet ramps communicating with an ice forming compartment  66  may be formed in other locations on the tray within the scope of the disclosure.  
         [0042]     The ejector mounting arm features  72  include a shaft-receiving semi-cylindrical bearing surface  84  formed in the first end wall  76 , a shaft-receiving semi-cylindrical bearing surface  86  formed in the second end wall  78 , a shaft-receiving aperture  88  formed through the second end wall  78 , and portions of each of a plurality of overflow channels  90  formed in each divider wall  80 . The shaft-receiving semi-cylindrical bearing surfaces  84 ,  86  and the shaft-receiving aperture  88  are formed concentrically about the rotation axis  91  of the shaft  48  of the ejector arm  44 . The shaft-receiving semi-cylindrical bearing surfaces  84 ,  86 , the shaft-receiving aperture  88  and the portions of the overflow channels  90  are sized to receive the shaft  48  of the ejector arm  44  for free rotation therein. The shaft-receiving semi-cylindrical bearing surfaces  84 ,  86 , the shaft-receiving aperture  88  and the portions of the overflow channels  90  are positioned to permit the longitudinal axis  50  of the shaft  48  of the ejector arm  44  to coincide with the rotation axis  91  when the ejector arm  44  is received in the tray  20  and rotated by the motor  42  and drive train  46 .  
         [0043]     As mentioned above, each partition or divider wall  80  extends laterally, relative to longitudinal axis  50 , across the ice tray  20 . In the illustrated embodiment, each divider wall  80  includes a forwardly facing lateral side surface  92 , a rearwardly facing lateral side surface  94  and a top surface  96 . The forwardly facing lateral side surface  92 , rearwardly facing lateral side surface  94  and top surface  96  are formed to include an overflow channel  90 . Each overflow channel  90  includes a top wall  98  positioned below the top surface  96  of the divider wall  80 . The top wall  98  of the overflow channel  90  is positioned near the desired maximum fill level of each compartment  66 . The first end wall  76  includes a rearwardly facing lateral side surface  100 . The second end wall  78  includes a forwardly facing lateral side surface  102 .  
         [0044]     As shown, for example, in  FIGS. 6 and 7 , each compartment  66  of ice tray  20  is configured to include a space  104  in which a tapered crescent-shaped ice cube  130  is formed. In each compartment  66 , one planar lateral side surface  100 ,  94 , from an end wall  76  or a divider wall  80 , respectively, is positioned relative to a second planar lateral side surface  92 ,  102 , from an adjacent divider wall  80  or end wall  78 , respectively, so that the first planar lateral side surface  100 ,  94  is spaced apart from the second planar lateral side surface  92 ,  102  at a downstream or narrow end  106  by a distance D 1   108  relative to an ejection path of movement or harvest direction. In each compartment  66 , the first planar lateral side surface  100 ,  94  is spaced apart from the second planar lateral side surface  92 ,  102  at an upstream or wide end  110  of the compartment  66  by a distance D 2   112  relative to said ejection path of movement. In the illustrated embodiment, the upstream end  110  of the compartment  66  is the end of the compartment  66  adjacent the ejection side  58  of the tray  20 . As shown, for example, in  FIG. 7 , the distance D 2   112  is greater than the distance D 1   108 .  
         [0045]     In the illustrated embodiment, each lateral side surface  92 ,  94 ,  100 ,  102  is planar, except for a bottom portion that smoothly curves into the bottom surface  82  to facilitate formation of the ice tray  20  using a molding process. As in prior art ice trays, the width of the compartment  66  may be narrower near the bottom and wider near the top, as shown, for example, in  FIG. 8 , to facilitate formation of the ice tray  20  using a molding process. The disclosed ice tray  20  forms tapered crescent-shaped ice cubes  130  which facilitate harvesting of the ice cubes by reducing heating of the tray  20  prior to ejection. Such an ice tray  20  is more particularly described in U.S. patent application Ser. No. 10/895,570 (Attorney Docket No. 1007-0579), filed Jul. 21, 2004, entitled Method and Device for Producing Ice Having a Harvest-facilitating Shape, which is assigned to the same assignee as the present invention, the disclosure of which is hereby incorporated by reference in its entirety.  
         [0046]     The ice ejector  22  includes a motor  42  having an output shaft, the ejector arm  44  and a drive train  46  coupling the output shaft of the motor  42  to the ejector arm  44 . Rotation of the output shaft of the motor  42  is transferred through the drive train  46  to induce rotation of the ejector arm  44  about its longitudinal axis  50 . As shown, for example, in  FIGS. 3, 5 ,  6  and  9 - 15 , the ejector arm  44  includes a shaft  48  formed concentrically about its longitudinal axis  50  and a plurality of ejector members  52  connected to and extending radially beyond the shaft  48 . In the illustrated embodiment, the ejector members  52  are crescent-shaped fins and are configured to extend from the shaft  48  into the ice tray  20  when the shaft  48  is rotated. The disclosed ejector members  52  are utilized to eject ice cubes  130  from the tray  20  and may be utilized to displace water in the compartments  66 , stir water in the compartments  66  or determine the size of the ice cubes  130  formed in the compartments  66 .  
         [0047]     As shown, for example, in  FIGS. 6 and 9 - 15 , each ejector member  52  includes a front face  118  and a rear face  120 . Each ejector member  52  also includes a first side wall, a second side wall and an outer wall  126  each extending between the front face  118  and the rear face  120 . In the illustrated embodiment, front face  118  and rear face  120  are each planar and are angularly displaced from each other by an angle  128 . In the illustrated embodiment, the angle between front face  118  and rear face  120  is approximately one hundred ninety-five degrees. Those skilled in the art will recognize that angle  128  is not critical and can assume other values.  
         [0048]     Outer wall  126  is formed about a radius  129 . Radius  129  is sufficient for a portion of the outer wall  126 , when ejector arm  44  is properly oriented and mounted to rotate about rotation axis  91 , to extend into the ice forming space  104  of a compartment  66  and be positioned vertically below the top wall  98  of the overflow channel  90  of the compartment  66  of ice tray  20 . Illustratively, radius  129  is sufficient to place outer wall  126  over half way between the shaft  48  and the bottom wall  82  of the compartment  66  without engaging the bottom wall  82  of the compartment, as shown, for example, in  FIG. 9 , when the ejector arm  44  is mounted for rotation about rotation axis  91 .  
         [0049]     Those skilled in the art will recognize that ejector members  52  may assume other configurations than those described above and still serve the purpose of acting as an ejector member  52 , a displacement member, a stirrer and an ice height detector arm. It is within the scope of the disclosure for ejector members  52  to be fingers, shafts or other structures extending radially beyond the outer walls of shaft  48 .  
         [0050]     An ice guiding cover  60  extends inwardly from the outside  62  of the tray  20  and is configured to include slide fingers with slots  64  formed therebetween to permit the ejector members  52  of the ejector arm  44  to extend through slots  64  in the cover  60  into the ice tray  20 . Ice cubes ejected from ejection side  58  of the tray  20  fall onto the slide fingers of the cover  60  and slide off of the outer edge of the cover  60  into the ice bin  24 .  
         [0051]     In the illustrated embodiment, motor  42  may be a stepper motor such as a Series LSD42 direct drive, 4 phase bifilar, stepping motor available from Hurst Manufacturing, a part of Emerson Motor Company, St. Louis, Mo. When such a motor  42  is utilized, the controller  30  includes a stepper motor controller  35  configured to control the rotational movement of the motor  42  by energizing the coils to start, stop and reverse the direction of the motor  42 , as more particularly described hereafter. The disclosed stepper motor  42  is supplied with four wires (described in the literature accompanying the Series LSD42 motor as white, blue, red and black) for energizing the coils of the motor  42 . The color coding described in the LSD42 motor literature will be utilized in describing the operation of the motor  42  and controller  30 , however, those skilled in the art will recognize that more or fewer wires with different color coding may be used to energize the windings of other stepper motors.  
         [0052]     The controller  30  induces clockwise rotation of the motor  42  by energizing the white and blue wires, white and red wires, black and red wires and black and blue wires in a cyclical fashion. The controller  30  induces counter-clockwise rotation of the motor  42  by energizing the black and blue wires, black and red wires, white and red wires and white and blue wires in a cyclical fashion. The stepper motor controller may be implemented on a separate integrated circuit  35 , such as a Model 220001 stepper motor controller available from Hurst Manufacturing or the like. Alternatively the stepper motor controller may be implemented in the microprocessor or microcontroller  34  of the controller  30  or through separate logic circuitry within the scope of the disclosure.  
         [0053]     In  FIG. 2 , a cover  41  ( FIG. 1 ) is removed from the icemaker assembly  10  to expose a circuit board  43  containing the controller  30 . As shown for example, in  FIG. 4 , the illustrated icemaker assembly  10  includes a controller  30  that is implemented at least in part by a microcontroller  34  and memory  40 . While many microcontrollers, microprocessors, integrated circuits, discrete components and memory devices may be utilized to implement controller  30 , the illustrated controller  30  utilizes a 72F324-J685 microcontroller from ST Microelectronics and EEPROM memory available as part number ULN2803A from Toshiba America Electronic Components Inc.  
         [0054]     The disclosed microcontroller  34  receives signals from various sensors and components, such as the ejector arm position sensor  150 , the over-fill level sensor  117  and the ice tray temperature sensor  160 , to control various components, such as motor  42 , heater  54  and the solenoid operated valve  32  in the water line  28 , so that the icemaker assembly  10  operates in the manner described. The controller  30  drives the stepper motor  42  to move the ejector arm  44  and an ice bin bail arm (not shown). The controller  30  also selectively actuates a triac  33  to control the water valve  32 , a triac  31  to control a heater  54  and a triac  37  to control a cooling fan  45 . The controller  30  receives feedback from temperature sensor  160 , the rotary detection emitter and sensor  152  providing position data relating to the ejector arm  44  and an optical sensor (not shown) to detect when the ice bin bail arm (not shown) is extended. The microcontroller  34  also reads data from and writes data to the memory  40 . The memory  40  may store energized winding data, motor direction data, ejector arm position data, fill time data, fill level error data and other information useful to the operation of ice maker assembly  10 .  
         [0055]     As shown, for example, in  FIGS. 17-21 , the icemaker assembly  10  includes an ejector arm position sensor  150  coupled to the controller  30 . Illustratively, the position sensor  150  is implemented using a rotary detection emitter and sensor  152  and an ejector arm encoder face cam  154  of the drive train  46 . Illustratively, rotary detection emitter and sensor  152  may be an Optek PHOTOLOGIC® slotted optical switch, such as Part Number OPB961N51 available from Optek Technology, Inc., 1215 W. Crosby Road Carrollton, Tex. 75006.  
         [0056]     The ejector arm encoder face cam  154  is one component of drive train  46  coupling motor  42  to the ejector arm  44 . By sensing the position of the ejector arm encoder face cam  154 , the position of the ejector arm  44  is established. The ejector arm encoder face cam  154  includes indicia  156  responsive to the rotary detection emitter and sensor  152  for indicating the angular position of the ejector arm  44 . In the illustrated embodiment, indicia  156  includes a plurality of holes formed in the ejector arm encoder face cam  154  for permitting signals transmitted by the rotary detection emitter to propagate to the rotary position sensor.  
         [0057]     As shown for example, in  FIGS. 18 and 19 , the ejector arm encoder face cam  154  and rotary detection emitter and sensor  152  are mounted so that the ejector arm encoder face cam  154  rotates within the slot between the sensor and emitter in the rotary detection emitter and sensor  152 . The solid portions of the ejector encoder face cam  154  interfere with the signal emitted by the rotary detection emitter when they are disposed between the emitter and sensor. Those skilled in the art will recognize that other indicia and rotary detection emitter and sensors, including indicia comprising reflective surfaces that reflect emitted signals onto a signal sensor are within the scope of the disclosure. It is within the scope of the disclosure for such reflective indicia to be coded so that the exact position of the ejector arm  44  can be determined during rotation.  
         [0058]     Preferably indicia  156  are present to selectively interfere, or not interfere, with the detection signal when the ejector arm  44  is positioned as shown at least in  FIG. 13 . Alternative methods and components may be used to detect the position of the ejector arm  44  within the scope of the disclosure including Hall sensor, tracking the energized winding of a stepper motor when such is used as the motor  42 , strobes and optical sensors and the like.  
         [0059]     As shown, for example, in  FIGS. 20-21 , a PCB  43  may include a rotation detector emitter and sensor  152  mounted in an orientation permitting a cylindrical axially extending wall  2158  of an alternative drum-type ejector arm encoder face cam  2154  to pass between its emitter and detector. Slots  2160 ,  2162  and  2164  are formed in the cylindrical axially extending wall  2158  to act as indicia  156 . In the illustrated embodiment, indicia  156  include a home position slot  2160 , a stall position slot  2162  and a heater disengagement slot  2164 . Illustratively, rotation detection emitter and sensor  152  is mounted so that the home slot  2160  is positioned between the emitter and sensor when the ejector arm  44  is positioned to dispose the entire ejector member  52  outside of the ice forming cavities  66 , i.e. in the home position such as that shown in  FIG. 13 . Those skilled in the art will recognize that a single home position slot  2160  would be sufficient to provide a calibration point for controlling the position of the ejector members  52  based on tracking the windings that are energized in a stepper motor or elapsed time and angular velocity or other open loop control algorithms for other electric motors.  
         [0060]     As shown, for example, in  FIG. 20 , the stall slot  2162  is located on the cylindrical axially extending wall  2158  of the ejector arm encoder face cam  2154  so that the slot  2162  is disposed between the emitter and sensor of the rotation detection emitter and sensor  152  when the ejector members  52  are in a position where they are likely to engage ice formed in the ice forming compartments  66 , i.e. in a position such as that shown in  FIG. 14 . Thus, sensor sends a stall condition signal to controller  30  during the period that it is able to detect the signal emitted by the emitter as a result of the stall slot  2162  being disposed between the sensor and emitter of the rotation detection emitter and sensor  152 . During an ejection cycle, the stall condition signal indicates that the conditions are ripe for a motor stall. When the ejector members  52  first engage the ice formed in the ice forming compartment  104 , the motor  42  and ejector arm  44  often stall. Thus, when the controller  30  receives a stall condition signal during an ejection cycle, the controller  30  is programmed to appropriately respond to a motor stall.  
         [0061]     In the illustrated embodiment, during a filling cycle, the termination of the stall condition signal while the ejector arm is rotating in the direction of arrow  56  ( FIGS. 3, 12  and  14 ) indicates to the controller  30  that the ejector members  52  have likely entered the space  104  in the ice forming compartments  66 . By keeping track of winding energization when the stepper motor  42  is utilized, or through utilization of other open loop position control algorithms when another type of motor is utilized, the controller  30  can appropriately position the ejector members  52  to act as displacement members to displace the appropriate amount of water to make discrete ice cubes  130  of various sizes.  
         [0062]     The heater slot  2164  is positioned on the cylindrical axially extending wall  2158  of the ejector arm encoder face cam  2154  relative to the emitter sensor to provide an indication that the ejector members  52  have rotated sufficiently into the ice forming compartments  66  to allow the heater  54  to be turned off during an ejection cycle. During a filling cycle, the controller  30  may utilize the signal generated by the sensor when the heater slot  2164  is disposed between the emitter and sensor to control the position of the ejector members  52  within the ice forming compartments  66 .  
         [0063]     The various positions of the ejector arm  44  are defined in terms of number of motor steps from home position ( FIG. 13 ) moving either in the harvest direction, the direction the arm  44  rotates during a harvest, or in the reverse direction, the direction opposite the harvest direction. In the illustrated embodiment, a full rotation of the ejector arm  44  is four thousand three hundred twenty (4320) motor steps. Those skilled in the art will recognize that the number of motor steps for complete rotation of the ejector arm  44  is dependent on the type of stepper motor  42  utilized and the gearing of the drive train  46 .  
         [0064]     In use, water is released from the water inlet  28  and flows down the end water inlet ramp  68  into the rear compartment  66   r . During the filling process, a portion of each ejector member  52  is disposed in the ice forming space  104  of its associated compartment as shown, for example, in  FIGS. 9-11 . The positioning of the ejector members  52  to act as displacement members is described more fully below. When sufficient water has entered the rear compartment  66   r  to raise the level of the water in the compartment  66   r  to the level of the top surface  98  of the overflow channel  90 , water overflows into the adjacent compartment  66  until the adjacent compartment  66  overflows into its adjacent compartment  66 . This fill and overflow process continues until water has filled each compartment  66 .  
         [0065]     Initially, in a first embodiment of the disclosure (as described more fully below), the fill time is based on the required time to fill the ice tray  20  to a particular location at which a known portion of the entire volume of the tray  20  has been filled and continued for a time proportional to the remaining volume of the tray  20  and the time required to fill to the particular location. In an alternative embodiment of the disclosure, the level of the water in the last compartment  66   f  to be filled may be sensed. In yet another embodiment of the disclosure, the water filling operation is based on a set time that is calibrated to estimate proper filling of all of the compartments  66  of the tray  20 . In each of the embodiments, the total time that the water solenoid valve  32  is open is adjusted in either the current or subsequent filling cycles based on a determination of a fill level error.  
         [0066]     Cessation of the filling operation may be accomplished in various ways, however, the illustrated icemaker assembly  10  closes a solenoid valve  32  positioned in the water line  28  between the water source  18  and the outlet of the water line  28  to stop the filling operation.  
         [0067]     As mentioned above, the controller  30  controls the motor  42  to position a portion of the ejector member  52  in the ice forming compartment  66  at some time during the filling operation to displace water. In the illustrated embodiment, the controller  30  controls the motor  42  to rotate the ejector arm  44  to submerge the entire ejector member  52  or a portion of the ejector member  52  adjacent the front face  118  or rear face  120  in the compartment  66  to act as displacement members during a filling cycle.  
         [0068]     In one current embodiment of icemaker assembly  10 , the motor  42  is stopped during filling to dispose a maximum volume of the ejector member  52  in the compartment  66  in the Fill Position, as shown, for example, in  FIG. 9 , to displace water so that a minimum sized ice cube  130  can be formed. The Fill Position is defined as a number of steps from Home Position in the harvest direction. The Fill Position is read from the EEPROM memory  40  on power-up. If a value cannot be read from the memory  40 , the default value of the Fill Position is one thousand eighty motor steps (90°) from the home position which disposes less than the maximum volume of the ejector member  52  in the compartment  66 .  
         [0069]     Those skilled in the art will recognize that the motor  42  can be stopped during filling to dispose a portion adjacent the front face  118  of the ejector member  52  in the compartment  66 , as shown, for example, in  FIG. 10 , to form a larger ice cube  130 . Alternatively, the motor  42  can be stopped during filling to dispose a portion adjacent the rear face  120  of the ejector member  52  in the compartment  66 , as shown, for example, in  FIG. 11 , to form a larger ice cube  130 . Those skilled in the art will recognize that the size of the ice cube  130  to be formed can be controlled by controlling the volume of the ejector member  52  positioned in the ice forming space  104  of the compartments  66 . This can be controlled by controlling the angular position of the ejector arm  44  by limiting the number of steps that the motor  42  is driven by the controller  30 .  
         [0070]     At some time after a filling cycle is completed, the controller  30  controls the motor  42  so that rotation of the ejector arm  44  is stopped with the ejector members  52  disposed completely outside the ice forming space  104  of each compartment  66  in the home position, as shown, for example, in  FIG. 13 , for a period of time to permit water to freeze in the ice tray  20 . After the water is frozen in the ice tray  20 , the controller  30  enables motor  42  to drive the ejector arm  44  in the direction of arrow  56 , i.e. in the harvest direction, causing ice in the tray  20  to be forced out of the ejection side  58  of the tray  20 . In the illustrated embodiment, ejection side  58  of the tray  20  is the side of the tray  20  adjacent the side wall  16  of the freezer compartment  12  to which the ice maker assembly  10  is mounted.  
         [0071]     If stirring while freezing is implemented, the controller  30  assumes the Freeze Stir state after the Fill Valve Open state. In the Freeze stir state, the controller  30  drives the ejector arm  44  to stir the water with the ejector members  52  in fast/low torque mode while the water valve  32  is closed and the heater  54  is off. During cooling, the controller  30  drives the motor  42  to repeatedly position portions of the ejector members  52  in the compartments  66  to stir the water therein as it cools toward freezing. The Stir Forward Position is defined as number motor steps from Home Position that the motor  42  should be advanced during stirring while cooling. If this value is zero, then the stirring is accomplished by continuously rotating the ejector arm  44  in the harvest direction. This value is read/write from EZ-Link. It is read from the EEPROM  40  on power-up. If a value cannot be read from the EEPROM  40  the default is two thousand one hundred motor steps (175°) from the home position. The value is written to the EEPROM  40  when a Harvest Arm Data Set message is received.  
         [0072]     The Stir Backward Position is defined as number motor steps from Home Position moving from the Stir Forward position in the reverse direction. If this value is zero, then stirring involves continuously rotating the ejector arm  44  in the harvest direction. The Stir Backward Position is read from the EEPROM  40  on power-up. If a value cannot be read from the EEPROM  40 , the default value of the Stir Backward Position is eight hundred motor steps (67°) from home. The value is written to the EEPROM  40  when a Harvest Arm Data Set message is received.  
         [0073]     Once the temperature of the water has lowered to a setpoint temperature close to the freezing point, the controller  30  assumes the Freeze Stir Home state wherein stirring is ceased and the ejector arm  44  is sent to the home position in fast/low torque mode. In the illustrated embodiment, a Stop Stir temp and a Stop Stir time are stored in memory  40 . The Stop Stir temp indicates the setpoint temperature and the Stop Stir time the duration at which the sensed temperature should be at or below the setpoint temperature during a stir cycle, before the stir cycle ends and the ejector arm  44  is removed from the tray  20 . The Stop Stir time and Stop Stir temp are read from the EEPROM  40  on power-up. If values cannot be read from the EEPROM  40 , the default value for Stop Stir temp is approximately 1° C. and the default value for Stop Stir time is five seconds. Both values are written to the EEPROM  40  when a Control Temperature/Timing Set message is received.  
         [0074]     Once the ejector arm  44  has reached the home position, the controller  30  assumes a Freeze Finish state in which the motor  42  is not driven, the heater  54  is off and the water valve  32  is closed. The controller  30  remains in the Freeze Finish state until the water freezes.  
         [0075]     If stirring while cooling is not implemented in the ice maker assembly  10 , the controller  30  assumes the Freeze Home state immediately after the Fill Valve Open State to bypass stirring and immediately drive the motor  42  to send the ejector arm  44  to the home position in fast/low torque mode.  
         [0076]     Filling of the tray  20  takes place in either the Fill Valve On or the Fill Valve Cold states. The algorithm in both states is exactly the same. The only difference is that Fill Valve On exits to Freeze Stir, and Fill Valve Cold exits to Freeze Home. The controller  30  assumes a Freeze Contingency state to bypass stir and touch off when there has been an error during harvest and there is likely excess water in the tray  20  that should be frozen and harvested so following fills do not overfill.  
         [0077]     At some time prior to the water freezing in each compartment  66 , the ejector arm  44  is turned until the entire ejector member  52  is disposed outside of the ice forming space  104  in each compartment  66 , as shown, for example, in  FIG. 13 . The ejector members  52  are disposed completely outside the ice forming space  104  of each compartment  66  in the home position for a period of time to permit water to freeze in the ice tray  20 .  
         [0078]     In the first and second disclosed embodiments of an ice maker assembly  10  implementing adaptive filling of the ice tray  20 , the controller  30  drives the motor  42  and tracks the position of the ejector arm  44  to allow the ejector members  52  to be utilized as level detectors to help determine the fill level of the ice tray  20 . In the first embodiment of the disclosed ice maker assembly  10  implementing adaptive filling of the ice tray  20 , after the water freezes in the ice forming compartments  66 , the ejector members  52  are rotated into contact with the top surface  132  of the ice cubes  130  to sense the size of the ice cube  130  formed in the present cycle in a touch-off method of adaptive filling  1600 . In an alternative embodiment of a method of adaptive filling  2200 , prior to the water freezing in the ice forming compartments  66 , the ejector members  52  are rotated into the ice forming space  104  in the compartments  66  to cause the water level therein to rise to actuate a sensor to sense the water fill level in the present cycle. In either of these two embodiments  1600 ,  2200 , knowing the position of the ejector members  52  facilitates determining the level to which the ice tray  20  was filled.  
         [0079]     In the illustrated embodiments, the controller  30  assumes a Harvest Ready state when the water is frozen in the ice tray  20 . In this state, the ejector arm  44  is positioned so that the ejector members  52  are located completely outside of the ice forming space in the compartments  66 , i.e. in a home position, the heater  54  is off and the water valve  32  is closed. The controller  30  waits in this state if a bail arm (not shown), or other ice bin fill level indicator, is in a position indicating that the ice bin  24  is full. Otherwise, the controller  30  begins to rotate the ejector arm  44  to begin either the ejection process or to determine the size of the ice cubes  130  that have been produced after the temperature of the ice drops to a Freeze Temp for an appropriate time Freeze Time. The pre-selected values of Freeze Temp and Freeze Time are stored in memory  40  and are selected so that when the values are met it can be safely assumed that the water is completely frozen following a stir cycle. These values are read from the EEPROM  40  on power-up. If a value cannot be read from the EEPROM  40 , the default value for Freeze Temp is −7° C. and the Freeze Time default value is thirty seconds. Both values are written to EEPROM  40  when a Control Temperature/Timing Set message is received.  
         [0080]     In each of the disclosed embodiments, at some time after an ice cube  130  has formed in each compartment  66 , the controller  30  actuates the heater  54  which heats the tray  20  to expand the same and melt a small amount of ice cube  130  adjacent the walls of each compartment  66 . The controller  30  assumes the Harvest Thaw state when the ejector members  52  of the ejector arm  44  are pushing on the ice  130  in slow/high torque mode. In this state, the heater  54  is on, the motor  42  is being driven in a slow/high torque state and the water valve  32  is closed. The melting of the cube  130  is believed to provide a lubrication layer between the ice cube  130  and the walls of the compartment  66 . The controller  30  actuates the motor  42  to turn its output shaft which is coupled through the drive train  46  to the ejector shaft  48 . The motor  42  drives the ejector shaft  48  to rotate about the rotation axis  91  in the direction of arrow  56  inducing the front face  118  of each ejector member  52  into contact with the ice cube  130  formed in its associated compartment  66 , as shown, for example, in  FIG. 14 . The front face  118  of each ejector member  52  contacts the top surface  132  of its associated ice cube  130  adjacent the narrow end of the cube  130  and exerts a force driving the narrow end of the cube  130  downwardly along the arcuate bottom surface  82  of the compartment  66 .  
         [0081]     The controller  30  assumes a Harvest Finish state when the ejector arm  44  has started to move while in the Harvest Thaw state indicating that the tray  20  has expanded sufficiently or enough of the ice cube  130  adjacent the tray  20  has melted to permit the ice cube  130  to be driven along the ejection path of motion. In the Harvest Finish state, the controller  30  drives the motor  42  in a fast/low torque mode along the ejection path of motion until it reaches the home position. While in the Harvest Finish state the controller  30  turns off the heater  54  and maintains the water valve  32  closed.  
         [0082]     The controller  30  assumes a Harvest Error state when a thaw cycle time has expired and the ejector arm  44  has not begun to drive the ice cubes  130  out of the ice tray  20  along the ejection path of motion. In the Harvest Error state, the controller  30  drives the motor  42  to move the ejector arm  44  back and forth in slow/high torque mode while it continues to cycle the heater  54  until the ejector arm  44  begins to move along the ejection path of motion. Once the ejector arm  44  begins to move along the ejection path of motion, the controller  30  assumes the Harvest Error Home state, similar to the Harvest Finish state, to drive the motor  42  in a fast/low torque mode to move the ejector arm  44  to the home position.  
         [0083]     Once the ejector arm  44  has proceeded along the ejection path of movement a sufficient distance to completely eject the ice cubes  130  from each compartment  66 , the controller  30  assumes a Fill Tray Cool state after leaving the Harvest Finish or the Harvest Error Home state, to permit the tray  20  to cool down so that when water is introduced it will provide a detectable change in temperature. During the Fill Tray Cool state, the ejector arm  44  is in the home position, the motor  42  is not being driven, the heater  54  is off and the water valve  32  is closed.  
         [0084]     After a sufficient time passes for the empty tray  20  to cool, the ejector member  52  is positioned so that a portion of the ejector member  52  is disposed in the ice forming space  104  in the compartment  66  to displace water during the next fill operation. The controller  30  thus assumes a Fill Arm Position state. In the Fill Arm Position state, the controller  30  drives the motor  42  to move the ejector arm  44  into the desired fill position, as shown for example, in  FIGS. 9-11 . While in the Fill Arm Position state, the heater  54  is off and the water valve  32  is initially closed. The controller  30  assumes a Fill Valve Open state while filling. This is the primary fill state wherein the motor  42  is not driven, the heater  54  is off and the water valve  32  is open.  
         [0085]     In the first embodiment of the disclosed method  1600  of adaptively filling an ice tray  20 , the ice tray  20  is initially filled with water by leaving the water valve  32  open for a period of time (the Fill Time) in a fill step  1602 , and then the ejector arm  44  is used to detect the size of the ice cube  130  formed in the tray  20  in a detection step  1604 . The Fill Time is adjusted in a fill adjustment step  1606  for the next or a subsequent filling cycle based on the error between the detected size of the cube  130  and the desired size of the cube  130 . Illustratively, the size of the ice cube  130  is detected by rocking the ejector arm  44  back and forth into contact with top surface  132  of the wide end and the top surface  132  of the narrow end of the frozen ice cube  130 . The angular position of the ejector arm  44  is recorded when the ejector arm  44  stalls due to contact of an ejector member  52  with the top surface  132  of its associated ice cube  130 . This data is then used in future fill cycles to maximize the size of the cubes  130  by adjusting the Fill Time.  
         [0086]     The first disclosed embodiment of adaptive filling of an ice tray  1600  utilizes the temperature sensor  160  to detect the presence of water at a water detect point during the initial fill step  1602 . In the illustrated embodiment, the temperature sensor  160  is located in the center compartment  66   c  of the ice tray  20  and the overflow method is utilized to fill the ice tray  20 . The tray  20  is allowed to cool following the previous ejection cycle. After determining that the tray has cooled sufficiently  1608 , the water valve is opened  1610  and the clock is started  1612 . The controller  30  monitors the temperature sensed at the detection point  1614  by the temperature sensor  160  to determine if there has been a temperature change  1616 . When a temperature change is detected it is determined whether the temperature change is of sufficient magnitude and duration to indicate the presence of water at the detection point  1618 .  
         [0087]     Since the water is introduced into the rear compartment  66   r , when the water finally overflows into the center compartment  66   c  inducing a change in the temperature of the center compartment  66   c , approximately half of the volume of the water required to fill all of the compartments  66  of the tray  20  has been dispensed. Thus, upon the temperature sensor  160  detecting a change in the temperature of the center compartment  66   c  induced by the presence of water in the center compartment  66   c , it may be assumed that an equal volume of water needs to be dispensed to fill all of the compartments  66  of the ice tray  20 . Thus, if the water valve  32  was open for a time period prior to the temperature sensor  160  sensing a change in temperature, it can be assumed that the water valve  32  should be left open for an equivalent time period to completely fill the tray  20 .  
         [0088]     In the first embodiment of the method of adaptively filling an ice tray  20 , the time differential between opening the solenoid valve  32  and the detection of a change in temperature of the center compartment  66   c  is stored in memory  40  as a Water Detect Point value  1620 . This Water Detect Point value is utilized to calculate the total time that the water valve  32  should remain open, or the Fill Time in the Fill Time calculation step  1622 . In the Fill Time calculation step  1622 , the controller  30  uses the following equation: 
 
Water Detect Point+Water Detect Point*Fill finish %=Fill Time. 
 
 Initially, the Fill finish % is set based on the ratio of the volume of ice compartments  66  of the tray  20  beyond the detect point to the volume of the compartments  66  of the tray  20  up to the detect point. In the illustrated embodiment, since the detect point is in the center compartment  66   c  at a location where the tray  20  should be half full when a temperature change is detected, the Fill finish % is initially set to one (1.00). Those skilled in the art will recognize that if the detect point is positioned at a different location in the tray  20  then the initial Fill finish % value would be different. For example, if the temperature sensor  160  were located to detect a temperature change in a compartment  66  which receives water when the tray  20  is one-quarter full, the initial Fill finish % would be set to three (3.00). 
 
         [0089]     The controller  30  utilizes both a timer and a detected change in temperature to control the filling of the tray  20  and to implement adaptive filling. The controller  30  utilizes clock pulses to keep track of how long the water valve  32  is on. Once it is determined that the Fill Time has elapsed  1624 , the water valve  32  is closed  1626 . If there is a power down in a fill state this value of the time elapsed since opening the water valve  32  is written to EEPROM  40  so that the filling step  1602  can continue upon restoration of power.  
         [0090]     While not shown in  FIG. 16 , the controller  30  tries to detect the presence of water at the detect point for a time period determined by the value of Fill Search Time, which is in units of line ticks. In the illustrated embodiment, the output of the temperature sensor  160  is converted from analog to digital and a number of analog to digital pulses or A/D counts are utilized to represent the sensed temperature. As water fills the tray  20  and fills the center compartment  66   c  in which the temperature sensor  160  is located, the water, because it is warmer than the tray  20 , causes a change in the temperature sensed by the temperature sensor  160 . Thus, once the water valve  32  is opened by the controller  30 , the controller  30  begins to compare temperature data received from the temperature sensor  160  to detect a temperature change  1616 .  
         [0091]     In the illustrated embodiment anytime two subsequent temperature sensor readings differ by one count of A/D, the time is recorded as a possible Water Detect Point. Then 1.2 seconds later, the possible Water Detect Point is verified as a legitimate temperature change, if the latest A/D reading is 5 counts or greater higher than the A/D reading at the possible Water Detect point. If it is not, the controller  30  looks for a new possible Water Detect Point between the present reading and all readings following the original possible Water Detect Point. If a new possible Water Detect Point cannot be found it simply continues to search. If the possible Water Detect Point is verified then the time from when the valve  32  was turned on until the possible Water Detect Point is considered the Water Detect Point. The Fill finish % is multiplied by the Water Detect Point to determine how much longer the valve  32  should remain on. This remaining valve on time is the Fill Finish Time. The fill will continue until the Fill Finish Time expires as long as the Water Detect Point+Fill Finish Time does not exceed the Max Fill Time. The water valve  32  can never be on for longer than the Max Fill Time. If no temperature change induced by water filling the tray  20  is ever detected, the Water Detect Point and the Fill Finish Time are set to zero, and the water valve remains on for the Fill Search Time only.  
         [0092]     Generally, as described above, the amount of time that the water valve  32  is opened is determined by time lapse between opening the water valve  32  and the detection of a temperature increase by the tray sensor  160  (the Water Detect Point) which is then added to the Water Detect Point multiplied by the Fill finish % to determine the Fill Time. However, to avoid overfilling of the tray, a Max Fill time is provided. Illustratively, the water valve  32  cannot be open for more than the Max Fill time for a single fill cycle. Thus, even if a temperature change is detected, thereby establishing a Water Detect Point, if the Fill Time calculated from the values of the Water Detect Point and the Fill Follow % is greater than the Max Fill time, the water valve  32  will be shut when the Max Fill time elapses rather than waiting for the calculated Fill Time to elapse.  
         [0093]     It may be preferable in some situations where the Water Detect Point is found to vary without a corresponding variance in water pressure to provide a digital filter to the Water Detect Point. Such a filter is implemented in one embodiment of the disclosed device and method by substituting a New Filtered Data value for the Water Detect Point in the above equations. The New Filtered Data value is defined as:  
       NewFilteredData   =           (     weight   -   1     )     *   PreviousFilteredData     +   WaterDetectPoint     weight         
 
 where the Previous Filtered Data is the value of the New Filtered Data from the previous fill cycle, the weight is a filtering factor and the Water Detect Point is the actual measured detect time in the current fill cycle. The weight is a value between 0 and 1 and desirable results have been obtained utilizing weight=0.4. Those skilled in the art will recognize that utilization of the digital filter will limit the ability of the described algorithm to compensate for momentary increases or decreases in water pressure experienced during the current filling cycle, but will still allow the algorithm to compensate for slow pressure drops in the fill line arising from clogging of the water line over time. 
 
         [0094]     The illustrated embodiment also stores a Fill Search Time which limits the amount of time the controller  30  will wait for the presence of water to be detected. If water is not detected prior to the Fill Search Time, the Fill Search time is utilized as the value of the Fill Time. The value is written to the EEPROM  40  when a Fill Time Set message is received.  
         [0095]     The Fill Finish Time is the amount of time the water valve  32  will stay open after the time that water is detected by the temperature sensor  160  sensing a temperature change. As previously stated, the value of the Fill Finish Time is calculated by multiplying the Water Detect Point by the Fill finish %. The Fill finish % is the percentage of the Water Detect Point that the water valve  32  should stay open after the time when the presence of water is detected at the detect point. The value of the Fill finish % is written to the EEPROM  40  when a Fill Time Set message is received.  
         [0096]     The EEPROM  40  also stores a value for the Fill Temp Delta Threshold. The Fill Temp Delta Threshold is the number of counts of A/D change in the temperature reading sensed by the temperature sensor  160  over a 1.2 second time period that will indicate the presence of water at the detect point.  
         [0097]     After it is determined that the water has frozen  1628 , the ejector members  52  are utilized to measures height of the surface of the ice cubes  1604  by touching off on the top surface  132  of the ice cubes  130 . If the ice cubes  130  are smaller than the ideal touch off value then the Fill finish % is increased  1630 . Likewise if the ice cubes  130  are too large the Fill finish % is decreased  1632 . Preferably the part of the ejector member  52  that contacts the ice cube  130  should be the one farthest from the shaft  48 . The illustrated ice maker assembly  10  includes ejector members  52  having planar front and rear faces. Ejector members  52  configured in such a manner are particularly useful in an ice maker assembly  10  that eliminates bulges on the top surface  132  of the ice cube  130 . A method and device for, among other things, eliminating such surface bulges that utilizes the disclosed ejection members  52  is disclosed in co-pending U.S. patent application Ser. No. 10/895,665 (Attorney Docket No. 1007-0574) filed Jul. 21, 2004, entitled Method and Device for Stirring Water During Icemaking, which is assigned to the same assignee as the present invention, the disclosure of which is hereby incorporated by reference in its entirety. When water is not stirred during ice making, it may be advantageous for ejection members having differently configured faces to be utilized, such as a concavely curved face or a face having a downwardly projecting finger adjacent the outer wall.  
         [0098]     In one illustrated embodiment, wherein the ice maker assembly  10  utilizes the touch-off technique for implementing adaptive fill  1600 , as shown for example in  FIG. 16B  after the Freeze Finish state, the controller  30  assumes the Freeze Harvest Direction Touch Off (“Freeze HD Touch Off”) state to perform a narrow side ice level determination step  1634 . The Freeze HD Touch Off state is assumed after the water has frozen to determine the height of the ice  130  by stalling the ejector arm  44  on the top surface  132  of the ice cube  130  adjacent the narrow end of the ice cube, as shown, for example, in  FIG. 14 . In the Freeze HD Touch Off state, the heater  54  is off and the water valve  32  is closed. The controller  30  drives the motor  42  to rotate the ejector arm  44  in the direction the ejector arm  44  moves during harvest by the number of steps required to complete one quarter of a full rotation from the home position, in the illustrated embodiment one thousand eighty steps. At some time during the rotation of the ejector arm  44  in the harvest direction, the end of the front face  118  of an ejector member  52  will engage the top surface  132  of its associated ice cube  130  and the ejector arm  44  will stall. After the ejector arm  44  stalls, additional energizations of the windings of the stepper motor  42  will not induce rotation of the ejector arm  44 . After the controller  30  has energized the windings in the appropriate patterns the appropriate number of times to drive an unobstructed ejector arm  44  one quarter rotation in the harvest or forward direction, the controller  30  then energizes the windings of the stepper motor  42  in the opposite sequence to reverse the direction of the motor  42  and the ejector arm  44  to move the ejector arm  44  back to the home position. The controller  30  records the number of steps taken to get back to the home position and subtracts it from the number of steps that were taken in the harvest direction. The difference provides an indication of angular position where the ejector arm  44  stalled on the ice  130 . Since the configuration and relative position of ejector arm  44  and tray  20  are known, the angular position of the ejector arm  44  provides an indication of the height of the ice cubes  130  formed in the tray  20 .  
         [0099]     In the illustrated embodiment, the controller  30  then assumes the Freeze Wide Direction Touch Off (“Freeze WD Touch Off”) state to check the height of the ice  130  on the opposite side of the tray  20  to perform a wide side ice level determination step  1636 . In the Freeze WD Touch Off state, the water is frozen and the height of the ice  130  is determined by stalling the ejector arm  44  as a result of the rear face  120  of the ejector members  52  touching the top surface  132  of the ice cube  130  adjacent the wide side of the compartments  66 . This state is similar to the Freeze HD Touch Off state except that the motor  42  is initially rotated in the direction opposite the harvest direction (i.e. in the direction of arrow  116  in  FIG. 13 ) to stall the ejector member  52  on the surface  132  of the ice cube  130  adjacent the wide end of the ice cube  130 . The controller  30  drives the motor  42  to rotate the ejector arm  44  in the direction opposite the direction the ejector arm  44  moves during harvest (i.e. in the direction of arrow  116  in  FIG. 13 ) by the number of steps required to complete one quarter of a full rotation from the home position, in the illustrated embodiment one thousand eighty steps. At some time during the rotation of the ejector arm  44  in the reverse direction (i.e. in the direction of arrow  116  in  FIG. 13 ), the end of the rear face  120  of an ejector member  52  will engage the top surface  132  of its associated ice cube  130  adjacent the wide end of the ice cube  130 . Upon engagement, the ejector arm  44  will stall so that the additional energizations of the windings of the stepper motor  42  will not induce rotation of the ejector arm  44 . After the controller  30  has energized the windings in the appropriate patterns the appropriate number of times to drive an unobstructed ejector arm  44  one quarter rotation in the reverse direction (i.e. in the direction of arrow  116  in  FIG. 13 ), the controller  30  then energizes the windings of the stepper motor  42  in the opposite sequence to reverse the direction of the motor  42  and drive the ejector arm  44  to move in the harvest or forward direction (i.e. in the direction of arrow  56 ) back to the home position. The controller  30  records and stores in memory  40  the number of steps taken to get back home and subtracts it from the number of steps that were taken in the reverse direction. The difference provides an indication of angular position where the ejector arm  44  stalled on the ice  130 . Since the configuration and relative position of ejector arm  44  and tray  20  are known, the angular position of the ejector arm  44  provides an indication of the height of the ice cubes  130  formed in the tray  20 .  
         [0100]     As described above, once the water is frozen, the ejector arm  52  is used to measure the height of the surface  132  of the ice  130 . The ice  130  is measured by rotating the ejector arm  44  in both directions and determining where the arm  44  stalled on the ice in each direction. In the illustrated embodiment, the controller  30  compares the touch off value on the inside of the cubes and the outside of the cubes  1638 . The controller  30  sets the inside touch off value as the ice height  1640  if it is smaller than the outside touch off value. Otherwise, the controller  30  sets the outside touch off value as the ice height  1642 . The controller  30  utilizes the smaller touch off value to determine whether the Fill finish % needs to be adjusted in an ice level comparison step  1644 . The smaller touch off value is utilized because the smaller the touch off value the bigger the cube  130 . If water is detected during the fill, which is evident by the Water Detect Point being non-zero, then the Fill finish % will be modified based on the touch off data in the fill time adjustment step  1606 . If the touch off data is equal to the Desired Touch Off then the Fill finish % is not adjusted. If the touch off data is less than Desired Touch Off (the tray is overfilled) then the Fill finish % is decreased by five percent in a fill time reduction step  1632 . If the touch off is greater than Desired Touch Off, the Fill finish % is increased by five percent in a fill time increase step  1630 .  
         [0101]     The Desired Touch Off value is stored in memory  40  and used by the controller  30  to determine whether or not to increase or decrease the Fill Time. In the illustrated embodiment, the default value for the Desired Touch Off is six hundred steps from Home Position. Thus, if the lower of the stored values of the HD Touch Off and WD touch off value is greater than six hundred, the controller  30  adjusts the Fill Time to achieve a smaller touch off value closer to six hundred steps by increasing the Fill finish % by 5 percent in a fill time increase step  1630 . If the lower of the stored values of the HD Touch Off and WD touch off value are less than six hundred, then the controller  30  will adjust the Fill finish % by decreasing it by 5 percent in a fill time reduction step  1632 . Following the fill adjustment step  1606 , the ice maker assembly  10  ejects the ice cubes  130  in an ejection step  1646  as described above and returns to determining if the tray is cold enough  1608  to begin the filling step  1602 .  
         [0102]     The illustrated controller  30  operates in a plurality of states in which it controls the motor  42 , heater  54  and solenoid fill valve  32 . The controller  30  has been described as assuming the Harvest Ready, Harvest Thaw, Harvest Finish, Harvest Error, Harvest Error Home, Harvest Finish, Fill Tray Cool, Fill Arm Position, Fill Valve Cold, Fill Valve Open, and Freeze Stir states. Those skilled in the art will recognize that the controller  30  can assume more or less states depending on the functionality desired in the ice maker assembly  10 . The disclosed invention can be implemented in ice maker assemblies that do not use the ejector members  52  to displace water during filling or that do not stir the water during cooling, within the scope of the disclosure.  
         [0103]     While not illustrated, during power up, the icemaker assembly  10  tries to return to the same conditions it was at when it powered down. The algorithm Current State is read from the EEPROM  40  at power up. When powering down occurs in most states, the state is recorded and stored in the EEPROM  40  and on power up the controller  30  simply returns to the state in which it was in during power down. Two exceptions are when there is a power down in the Freeze Stir, Freeze Stir Home states. When a power down occurs in the Freeze Stir, Freeze Stir Home states, the controller  30  enters the Freeze Home state on power up, to avoid the ejector arm  44  getting stuck during stirring.  
         [0104]     Another exception is when a power down occurs during the Fill Valve Open state which will go to the Fill Valve Cold states. If there is a power down in the Fill Valve Cold or Fill Valve Open states, the valve on time is written to the EEPROM  40  so the controller  30  does not overfill the tray  20  when returning on power up.  
         [0105]     All temperature information is reported to the controller  30  as A/D data and is stored internally in memory  40 . Illustratively, all temperatures are A/D values that correspond to the desired temperature. Alternatively, temperatures could be offsets from a detected actual freezing point temperature. Among the temperatures and times recorded and stored are the Fill temp, Fill temp/time, the Stop Stir temp, Stop Stir time, Freeze temp, Freeze time and the Water Present temp delta.  
         [0106]     The Fill temp is the temperature at which the tray should be before opening the water valve  32  to fill the tray  20  and the Fill temp/time is time at which the tray  20  should be at the Fill temp before opening the water valve  32  so that there will be a detectable temperature change when water contacts the temperature sensor  160  during filling. The Fill temp and Fill temp/time are read from the EEPROM  40  on power-up. If a value cannot be read from the EEPROM  40 , the default value for Fill temp is set to approximately −3° C., the default value for Fill temp/time is five seconds. Both values are written to EEPROM  40  when a Control Temperature/Timing Set message is received.  
         [0107]     In the disclosed second embodiment of adaptively filling an ice tray  2200 , the level to which the ice tray  20  has been filled is detected by displacing water with the ejector members  52  until the water rises to a level where it is detected by an overfill sensor  117  in the overflow trough  114 , as shown for example, in  FIGS. 22 and 23 . In the illustrated embodiment, the overflow trough  114  is formed in the first end wall  76  of the front compartment  66   f  of the ice tray  20 . Water flows into the overflow trough  114  when each compartment  66  is filled to the desired level and the ejector members  52  are in a desired position to displace water in the compartments  66 . The overflow sensor  117  may be a conductor pin insulated from the tray  20  and positioned to sense presence of water in the overflow trough  114 .  
         [0108]     In the second embodiment of the disclosed ice maker assembly  10  the stepper motor  42  is utilized to precisely fill the compartments  66  of the ice tray  20 . Because a stepper motors can advance and reverse with good resolution of its output shaft&#39;s angular position without using an encoder, such a motor can be used to precisely fill the ice tray  20 , regardless of temperature in the freezer, auto defrost time, local water pressure and/or hardness, age of valve, etc. It is also within the scope of the disclosure to use a stepper motor  42  with an encoder  150  or another reversible motor with an encoder  150  to implement the adaptive filling process of the second embodiment. In the second embodiment of the ice maker assembly  10 , the ejector members  52  and the overflow sensor  117  are utilized to detect available displaced/un-displaced volumes in the compartmentalized tray  20 . When the disclosed ejector members  52  are disposed in the ice forming spaces  104  of the compartments  66  of the tray  20 , they act to displace water present in the compartment. By alternatively operating the valve  32  and rotating the ejector arm  44  farther into and out of the ice forming compartments  104 , the ice tray  20  can be precisely filled to a desired level.  
         [0109]     In the second embodiment, the tray is initially filled for an anticipated accurate Fill Time in an initial fill step  2202 . The Fill Time used in the initial fill step  2202  could be determined as described in the first embodiment above or could be a calibrated Fill time set at the factory. After the Fill Time has expired the water valve  32  is closed by the controller  30  in a close valve step  2204 . Following the close valve step  2204 , the controller  30  determines the fill level of the tray  20  in a check fill level step  2206 .  
         [0110]     In the illustrated embodiment, the check fill level step  2206  is accomplished by the controller  30  driving the motor  42  to position the ejector members  52  in the compartments  66  to displace sufficient water to cause overflow of the water into the overflow trough  114  at the front of the tray  20  if the tray  20  is properly filled in an initial ejector advancement step  2210 . It is then determined if water is present in the overflow  2212 . If water is present in the overflow trough  114  after so positioning the ejector members  52 , the overflow sensor  117  senses the presence of water in the overflow trough  114 , then the controller drives the motor  42  to rotate the ejector arm  44  a few steps in the reverse direction in a partial withdrawal step  2214 . After this initial rotation in the reverse direction it is again determined if water is present in the overflow trough  2216 . If water is no longer detected in the overflow trough  114 , then the tray is properly filled and the Fill time is not adjusted for the next cycle. If water is still detected in the overflow trough following the rotation in the reverse direction the tray  20  was overfilled during the current filling cycle. If it is determined that the tray  20  has been overfilled, the controller  30  drives the motor  42  to rotate the ejector arm  44  incrementally in the reverse direction until water is no longer detected in the overflow trough  114  in a fill level reduction determination step  2218 . In the fill level reduction determination step  2218 , the ejector arm is repeatedly incrementally withdrawn  2220  from the compartment  66  and the presence of water in the overflow is repeatedly sensed  2222 . The Fill time is reduced during the next fill cycle based on the position of the ejector arm  44  when water is no longer detected in the overflow trough  114  in the reduce Fill time step  2224 .  
         [0111]     If water is not detected in the overflow trough  114  after the initial ejector advancement step  2210 , then the tray  20  was under-filled during the most recent filling cycle. In an under-fill situation, the controller  30  increases the Fill Time  2226 . The increasing the Fill Time step  2226  can be accomplished either by repeatedly opening the valve  32  for small periods until the presence of water is detected in the overflow trough  114  and/or by adjusting the Fill Time accordingly for the next filling cycle. It is also within the scope of the disclosure to repeat the advancing, sensing and adjusting steps until the desired fill level is achieved.  
         [0112]     While two specific embodiments of methods for detecting the level to which the ice tray  20  has been filled have been disclosed, it is within the scope of the disclosure for the fill level of the tray  20  to be detected in other manners. For instance, it is within the scope of the disclosure to use an optical of sonic sensor to detect the presence of water.  
         [0113]     While the disclosed invention may be implemented using a conventional ice tray  20 , it is described as being implemented using a weirless tray which fills on an overflow principal. Absence of a weir gives several advantages that are more fully disclosed in the incorporated U.S. patent application Ser. No. 10/895,792 (Attorney Docket No. 1007-0577) filed Jul. 21, 2004, entitled Method and Device for Eliminating Connecting Webs Between Ice Cubes.  
         [0114]     Although specific embodiments of the invention have been described herein, other embodiments may be perceived by those skilled in the art without departing from the scope of the invention as defined by the following claims.