Patent Publication Number: US-2016227981-A1

Title: Motor control based on vibration sensing

Description:
TECHNOLOGICAL FIELD 
     Embodiments of the present invention relate to various systems, method, and apparatuses for controlling motors used in domestic appliances, including dishwashers, and more particularly, for controlling motors used in domestic appliances based on feedback from one or more vibration sensors within the domestic appliance. 
     BACKGROUND 
     A dishwasher typically employs a series of cycles for cleaning dishware disposed within a tub portion of the dishwasher. Each of these cycles generates a level of noise due to the operation of various motors in communication with pumps, vent fans, and/or the like. For example, a circulation pump utilized to pump water and/or a cleaning solution throughout the dishwasher and to spray the water and/or cleaning solution onto the dishware may generate noise during a cleaning cycle. A drain pump may generate noise while pumping the water, soils, and/or cleaning solution out of the dishwasher after the cleaning cycle has been completed. As yet another example, a blower comprising a vent fan and a vent fan motor may generate noise while circulating air throughout the dishwasher during a drying cycle. 
     BRIEF SUMMARY 
     Embodiments of the present invention seek to monitor the noise generated from the various pumps and use that information for more efficient control of various systems or processes within the dishwasher. For example, in some embodiments, the noise created by the circulation pump/motor, drain pump/motor, and/or vent fan/motor of the blower can be monitored and used to adjust operation of those components for more efficient operation of the dishwasher. Additionally, in some cases, operation of the circulation pump/motor, drain pump/motor, and/or vent fan/motor of the blower can adjusted to also minimize the level of noise generated by dishwasher. 
     Some embodiments of the present invention provide a dishwasher comprising a vibration sensor in communication with a controller for controlling the operation of a blower. For example, according to an embodiment, a dishwasher comprising a tub; a blower configured to remove air from the tub, the blower comprising a vent fan and a vent fan motor, wherein the vent fan motor is configured to cause the vent fan to rotate and to evacuate the air from the tub; a vibration sensor (e.g., a microphone or an accelerometer) configured to sense operating characteristics of the vent fan motor; and a controller in communication with the blower and the vibration sensor, wherein the controller is configured to: cause the vent fan motor to operate at variable speeds; receive input from the vibration sensor indicating operating characteristics of the vent fan motor; determine whether the received operating characteristics of the vent fan motor satisfy preferred operating characteristics of the vent fan motor; and adjust, in response to determining that the received operating characteristics of the vent fan motor do not satisfy the preferred operating characteristics, the speed of the vent fan motor. Additionally, the operating characteristics of the vent fan motor comprise an operating frequency; and the controller is also configured to determine whether the received operating characteristics of the vent fan motor satisfy the preferred operating characteristics of the vent fan motor by determining whether the operating frequency of the received operating characteristics of the vent fan motor satisfies a preferred operating frequency. Moreover, the controller may be additionally configured to determine a rotation speed of the vent fan motor, wherein determining a rotation speed of the vent fan motor comprises applying a Fast Fourier Transform and/or digital waveform processing to at least a portion of the operating characteristics. The operating frequency may be determined based at least in part on received changes in sound pressure generated by the vent fan motor. Additionally, the preferred operating characteristics are configured to minimize noise generated by the vent fan motor and/or minimize an amount of energy used by the dishwasher. In various embodiments, the vibration sensor is in contact with the vent fan motor. 
     Moreover, in various embodiments the dishwasher further comprises a temperature sensor configured to sense an air temperature within the tub; and the controller is further configured to determine whether the received operating characteristics of the vent fan motor and the sensed air temperature satisfy preferred drying characteristics; and adjust, in response to determining that the received operating characteristics of the vent fan motor and the sensed air temperature do not satisfy the preferred drying characteristics, the speed of the vent fan motor. 
     In yet another embodiment, the dishwasher further comprises a pump (e.g., a circulation pump and/or a drain pump) and a pump motor configured to drive the pump, wherein the controller is further configured to: cause the pump motor to operate at variable speeds; receive input from a pump vibration sensor indicating operating characteristics of the pump motor; determine whether the received operating characteristics of the pump motor satisfy preferred operating characteristics of the pump motor; and adjust, in response to determining that the received operating characteristics of the pump motor do not satisfy the preferred operating characteristics, the speed of the pump motor. 
     Various embodiments are directed to methods of operating a dishwasher blower comprising a vent fan and a vent fan motor associated with a dishwasher. The method may comprise: causing the vent fan motor to operate at variable speeds; receiving input from a vibration sensor indicating operating characteristics of the vent fan motor; determining whether the received operating characteristics of the vent fan motor satisfy preferred operating characteristics of the vent fan motor; and adjusting, in response to determining that the received operating characteristics of the vent fan motor do not satisfy the preferred operating characteristics, the speed of the vent fan motor. In various embodiments, the operating characteristics of the vent fan motor comprise an operating frequency, and said determining comprises determining whether the received operating characteristics of the vent fan motor satisfy the preferred operating characteristics of the vent fan motor by determining whether the operating frequency of the received operating characteristics of the vent fan motor satisfies a preferred operating frequency. Determining may comprise determining a rotation speed of the vent fan motor, wherein determining a rotation speed of the vent fan motor comprises applying a Fast Fourier Transform and/or digital waveform processing to at least a portion of the operating characteristics. 
     In various embodiments, the method additionally comprises: receiving input from a temperature sensor indicating an air temperature within the dishwasher; determining whether the received operating characteristics of the vent fan motor and the sensed air temperature satisfy preferred drying characteristics; and adjusting, in response to determining that the received operating characteristics of the vent fan motor and the sensed air temperature do not satisfy the preferred drying characteristics, the speed of the vent fan motor. 
     In yet another embodiment, the method comprises: causing a pump motor associated with a pump (e.g., a circulation pump and/or a drain pump) to operate at variable speeds; receiving input from a pump vibration sensor indicating operating characteristics of the second motor; determining whether the received operating characteristics of the pump motor satisfy preferred operating characteristics of the pump motor; and adjusting, in response to determining that the received operating characteristics of the pump motor do not satisfy the preferred operating characteristics, the speed of the pump motor. 
     Other embodiments are directed to a computer program product for operating a dishwasher blower comprising a vent fan and a vent fan motor associated with a dishwasher, wherein the computer program product comprises a non-transitory computer readable storage medium having program code portions stored thereon, the program code portions being configured when said computer program product is run on a control device to: (1) cause the vent fan motor to operate at variable speeds; (2) receive input from a vibration sensor indicating operating characteristics of the vent fan motor; (3) determine whether the received operating characteristics of the vent fan motor satisfy preferred operating characteristics of the vent fan motor; and (4) adjusting, in response to determining that the received operating characteristics of the vent fan motor do not satisfy the preferred operating characteristics, the speed of the vent fan motor. In various embodiments, the operating characteristics of the vent fan motor comprise an operating frequency, and said determining comprises determining whether the received operating characteristics of the vent fan motor satisfy the preferred operating characteristics of the vent fan motor by determining whether the operating frequency of the received operating characteristics of the vent fan motor satisfies a preferred operating frequency. The determining process may comprise determining a rotation speed of the vent fan motor, wherein determining a rotation speed of the vent fan motor comprises applying a Fast Fourier Transform and/or digital signal processing to at least a portion of the operating characteristics. 
     In various embodiments, the computer program code portions are further configured when said computer program product is run on a control device to: receive input from a temperature sensor indicating an air temperature within the dishwasher; determine whether the received operating characteristics of the vent fan motor and the sensed air temperature satisfy preferred drying characteristics; and adjust, in response to determining that the received operating characteristics of the vent fan motor and the sensed air temperature do not satisfy the preferred drying characteristics, the speed of the vent fan motor. 
     In yet other embodiments, the program code portions are further configured when said computer program product is run on a control device to: cause a pump motor associated with a pump (e.g., a circulation pump and/or a drain pump) to operate a variable speeds; receive input from a pump vibration sensor indicating operating characteristics of the pump motor; determining whether the received operating characteristics of the pump motor satisfy preferred operating characteristics of the pump motor; and adjust, in response to determining that the received operating characteristics of the pump motor do not satisfy the preferred operating characteristics, the speed of the pump motor. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       Having thus described embodiments of invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein: 
         FIG. 1  is a perspective view of a partially exposed dishwasher, in accordance with some embodiments discussed herein; 
         FIG. 2  is a schematic diagram of a blower according to various embodiments of the present invention; 
         FIG. 3  is an illustration of a cross-sectional front view of a dishwasher during a wash cycle, in accordance with some embodiments discussed herein; 
         FIG. 4  is a flowchart illustration of a method according to some embodiments discussed herein; 
         FIG. 5  is an illustration of exemplary data received by a vibration sensor according to some embodiments discussed herein; 
         FIG. 6  is a schematic diagram of a circulation pump according to some embodiments discussed herein; 
         FIG. 7  is a schematic diagram of a drain pump according to some embodiments discussed herein; 
         FIG. 8  is a flowchart illustration of a method for optimizing operation of a circulation pump according to some embodiments discussed herein; and 
         FIG. 9  is a flowchart illustration of a method of optimizing operation of a drain pump according to some embodiments discussed herein. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. Indeed, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout. 
       FIG. 1  illustrates one example of a dishwasher  10  capable of implementing various embodiments of the present invention. Such a dishwasher  10  typically includes a tub  12  (partly broken away in  FIG. 1  to show internal details), having a plurality of walls (e.g., side wall  13 ) for forming an enclosure in which dishes, utensils, and other dishware may be placed for washing. As known in the art, the dishwasher  10  may also include slidable lower and upper racks (not shown) for holding the dishes, utensils, and dishware. 
     The tub  12  may include a sump  14  in which wash water or rinse water is collected, typically under the influence of gravity. The wash/rinse water may be pumped by a circulation pump  50  (such as through circulation conduit  26 ) to one or more spray arms (e.g., lower spray arm  20  and/or middle spray arm  25 ) mounted in the interior of the tub  12  for spraying the wash/rinse water, under pressure, onto the dishes, utensils, and other dishware contained therein. 
     The sump  14  and spray arms  20 ,  25  may be in fluid communication with various operational components of the dishwasher  10 . For example, a water valve (not shown) and a drain pump  42  may each be in fluid communication with the sump  14  and spray arms  20 ,  25 . The water valve may be configured to activate (e.g., open, turn ON, etc.) to direct water from a fluid supply/source to the tub  12  of the dishwasher  10 . The water valve may also be configured to activate (e.g., close, turn OFF, etc.) to stop directing water to the tub  12 . The drain pump  42  may be configured to activate (e.g., turn ON) to remove water from the sump  14  or tub  12 . The drain pump  42  may also be configured to deactivate (e.g., turn OFF) to stop removing water from the sump  14  or tub  12 . In some embodiments, water and soil collected in the sump  14  can be pumped out of the dishwasher  10  by the drain pump  42  through a drain hose  23 . The drain hose  23  comprises a hose that extends from the drain pump  42 , or otherwise from the dishwasher  10 , to a drain plumbing system (e.g., a residential drain plumbing system) and is configured to remove water and soils from the dishwasher  10  to the drain plumbing system. Thus, through selective activation of the water valve/drain pump, water may be selectively added or removed from the tub  12  of the dishwasher  10 . The drain pump and the water valve may be configured to be automatically activated (i.e., electrically opened and closed), though one skilled in the art will appreciate that such components may be actuated in different ways such as, for example, mechanically, hydraulically, and/or in other appropriate manners. 
     In various embodiments, a door  18  may be pivotably engaged with the tub  12  to selectively permit access to the interior of the tub  12 . The door  18  closes to cover and seal the tub  12  when the dishwasher  10  is in operation. Although not indicated in  FIG. 1 , in some instances, the door  18  may comprise an inner wall and an outer wall. The door  18  may include a handle member disposed on an outer surface of the outer wall, to provide the user with a grasping portion. Moreover, in various embodiments, the door  18  may comprise a user interface  19  configured to receive user input during operation of the dishwasher  10 . 
     In various embodiments, the door  18  comprises a drying system of the dishwasher  10  configured to facilitate removal of moisture from the dishware during a drying cycle so as to facilitate drying the dishware disposed within the tub  12 . Although a substantial amount of the water used during wash and rinse cycles runs off the dishware due to gravity, some residual water often remains on the dishware following the wash and/or rinse cycles. In various embodiments, the drying system may comprise a duct and a blower  60  (e.g., a centrifugal blower) configured for evacuating humid air from the tub  12 . The humid air drawn into the duct by the blower  60  may, in some cases, be condensed and fed back into the dishwasher tub  13  or sump  14  for potential re-use or draining. Additionally, the humid air (or a portion thereof) may, in some cases, be vented to the external environment through an external vent (not shown). Moreover, a heating element may be configured to apply heat to the tub  12  during the drying cycle in order to facilitate evaporation of residual water present on the dishware. 
     In various embodiments, proxy sensors (e.g., tachometers, Hall-effect sensors, and/or the like) may be utilized to monitor various characteristics of the dishwasher components (e.g., motor rotation speed, pump speed, and/or the like) that may result in noise generation. In various embodiments, the dishwasher may also comprise sound insulation to surround a substantial portion of the dishwasher components (e.g., a blower) in order to minimize unwanted noise from being heard by a user. 
     As illustrated in  FIG. 2 , the blower  60  may comprise a motor  61  comprising one or more motor components (e.g., armatures, commutator bars, brushes, rotors, stator windings, cooling fans, bearings, and/or the like) collectively configured to operate a vent fan  62  at a defined rotational speed as determined by a controller  40 . In various embodiments, the vent fan  62  may comprise a plurality of vanes (not shown) extending from a central hub, and configured to rotate about the central hub and thereby move air out of the tub  12 . Collectively, the blower  60  may be configured for evacuating air from within the tub  12 , such as during a drying cycle. Although illustrated in  FIG. 1  as being incorporated into the door  18 , it should be understood that the blower  60  may be located in a variety of locations within the dishwasher  10  such that the blower  60  may evacuate air from within the tub  12  during a drying cycle (e.g., on the top wall of the dishwasher tub). As will be described in greater detail herein, the blower  60  may be in communication with a controller  40  and may activate (e.g., turn ON) in response to receiving a signal (e.g., a pulse-width signal) from the controller  40 . The blower  60  may, in some embodiments, be configured to operate in a cyclic manner during the drying cycle. In various embodiments, the blower  60  may be cyclically actuated or pulsed on and off. For example, the blower may be selectively activated, pulsed, or cycled rather than being constantly on. The blower  60  may be selectively activated by receiving a signal from the controller  40 , such as a Pulse-Width Modulation (PWM) signal comprising a plurality of pulses each having a defined pulse-width, or by receiving an activation signal of a particular voltage. Thus, the received signals may be digital or analog. In various embodiments, the frequency of the pulses, the relative length of the pulses, or the voltage level associated with the signal received by the blower  60  may be directly related to the speed at which the motor  61  rotates the vent fan  62 . For example, a higher frequency of received pulses, a longer pulse-width of the received pulses, or a higher voltage may correlate to a faster vent fan rotation speed. In various embodiments, a single blower  60  comprising a motor  61  and a vent fan  62  may be used to facilitate drying of the dishware within the dishwasher. 
     In various embodiments, the motor  61  may have associated preferred operating characteristics. Such preferred operating characteristics may be associated with a preferred speed of rotation that may correspond to efficient operation of the motor, such as may result in, for example, longer life of the motor and/or a quiet operating state during which the motor generates a low sound level. In various embodiments, the preferred operating characteristics may be influenced by ambient conditions surrounding the motor  61 . For example, the preferred speed of rotation may be influenced by the temperature of the motor  61 . Moreover, the motor  61  may be associated with a high sound level operating condition. For example, such high sound level operating condition may correspond to a harmonic frequency of one or more motor components, and may be influenced by ambient conditions around the motor  61 . For example, a motor or pump (e.g., motor  61 ) operating at 3000 revolutions-per-minute (RPM) may emit high sound pressure levels due to brush noise, bearing whine, or other motor inefficiencies. Therefore, adjusting the speed of the motor to 3066 RPM or 2933 RPM may result in lower generated sound levels and/or more efficient motor operation. 
     The blower  60  may be positioned proximate the top of the dishwasher tub  13  (e.g., in the door  18  such that an inlet of the blower  60  is disposed on an interior wall or other interior portion of the door  18 ). In such a position, the blower  60  is configured to draw or force air, such as moist air comprising vaporized water present within the tub  12  from the tub  12  toward the duct inside the door  18  (e.g., during a drying cycle). In some embodiments, the inlet may include a plurality of louvered fins (not shown) forming a barrier to minimize water (from spray or in the form of airborne droplets) from being pulled into the blower  60 . In various embodiments, the dishwasher  10  may additionally comprise a heating device or element (not shown) configured to heat the air within the tub  12 . Heating the air causes the air to rise toward an upper portion of the tub  12  and toward the inlet of the blower  60 . 
     The duct may extend from an inlet end to an outlet end in the door  18  between an inner wall and an outer wall of the door  18 . The inlet end of the duct may be in communication with the blower such that moist air drawn out of the tub  12  by the blower  60  is directed into the inlet end of the duct. The duct may at least partially define a tortuous path between the inlet opening and the outlet opening that is configured to facilitate condensation of vaporized water from warm air as the warm air and vaporized water are directed through the duct from the inlet toward the outlet. The outlet end of the duct may be in communication with a drain opening disposed proximate a bottom portion of the tub  12 . The drain opening may be disposed on the interior wall or other interior portion of the door assembly such that as water condenses to form liquid water, the water flows through the duct, out the drain opening, and into the bottom of the tub  12  to be collected in the sump  14  of the dishwasher  10 . As the liquid water is drained through the drain opening, the resulting less humid air flowing through the duct is directed to the outlet end of the duct which may be disposed on the outer wall or other outer portion of the door assembly, such that the less humid air (i.e., as a result of the condensation process) exits the dishwasher  10 . 
     In some embodiments, certain of the particular operational components of the dishwasher (e.g., water valve, drain pump  42 , corresponding hoses and wires, etc.) may be housed, disposed, or otherwise positioned within a base portion  22  positioned beneath the tub  12 . In some instances, the base portion  22  may be a separate component with respect to the tub  12 , such as, for example, a molded polymer component, while in other instances the base portion  22  may be integral with the tub  12  such that the side walls forming the tub  12  also at least partially form the base portion  22 . 
     Operation of the dishwasher  10  typically includes execution of wash cycles having various parameters of the dishwashing process. In particular, the dishwasher  10  may be in an operating mode when undergoing these wash cycles. Moreover, each wash cycle may have different positions that correspond to current operations of the components of the dishwasher (e.g., activating/deactivating the drain pump, activating/deactivating the circulation pump, activating/deactivating the water valve, activating/deactivating a heating element, etc.). 
     Along these lines, a controller (e.g., the controller  40  shown in  FIGS. 1 and 2 ) may be used to communicate with certain components of the dishwasher  10 . The controller  40  may be housed inside the base portion  22  of the tub  12  or other location so as to facilitate communication with various components of the dishwasher  10 . In the depicted embodiment, the controller  40  is housed in the base portion  22  of the tub  12  and is configured to communicate with the circulation pump  50 , the circulation pump motor  51 , the drain pump  42 , and/or the drain pump motor  43 . Embodiments of the present invention contemplate communication of the controller with any of the components of the dishwasher (e.g., drain pump  42 , water valve, blower  60 , etc.). In this way, the controller  40  can control activation/deactivation of any of the components of the dishwasher. As described in greater detail herein, the controller  40  may also be in communication with various sensors configured to detect operating conditions in the dishwasher  10 . Furthermore, the controller  40  may be configured to communicate with the dishwasher  10  to determine the current position of the wash cycle being executed by the dishwasher  10 . 
     In various embodiments, the controller  40  may be in communication with one or more vibration sensors (e.g., vibration sensor  63  associated with the blower  60 , vibration sensor  45  associated with the drain pump  42 , and/or vibration sensor  53  associated with the circulation pump  50 ), such as a microphone, an accelerometer, a piezoelectric sensor, and/or the like, configured to sense vibrations and/or sound pressure level vibrations emitted by one or more dishwasher components. For example, the vibration sensor  63  may be configured to sense a sound pressure level generated by the motor  61  associated with the blower  60 . In various embodiments, the one or more vibration sensors may be coupled to the controller  40  or may be located away from the controller  40 . For example, the vibration sensor  63  may be located proximate to and/or in contact with the blower  60  (or its various components), and may be configured to sense vibrations, such as sound pressure level vibrations, generated by the blower  60 . The vibration sensor  63  may be positioned in relation to at least a portion of the blower  60  (e.g., the motor  61 ), such that the vibration sensor  63  detects vibrations generated by the blower  60  while in operation. For example, the vibration sensor  63  may be configured to sense vibrations (e.g., sound vibrations) generated by the one or more motor components rotating within a motor housing. In various embodiments, the vent fan  62  may comprise a single fan, although in other embodiments the vent fan  62  may comprise a plurality of fans. 
     Similarly, vibration sensor  45  may be located proximate to and/or in contact with the drain pump  42  (or its various components), and may be configured to sense vibrations, such as sound pressure level vibrations, generated by the drain pump  42 . The vibration sensor  45  may be positioned in relation to at least a portion of the drain pump  42  (e.g., the drain pump motor  43 ), such that the vibration sensor  45  may be configured to sense vibrations (e.g., sound vibrations) generated by the one or more motor components rotating with a motor housing. 
     Moreover, in various embodiments, vibration sensor  53  may be located proximate to and/or in contact with the circulation pump  50  (or its various components), and may be configured to sense vibrations, such as sound pressure level vibrations, generated by the circulation pump  50 . The vibration sensor  53  may be positioned in relation to at least a portion of the circulation pump  50  (e.g., the circulation pump motor  51 ), such that the vibration sensor  53  may be configured to sense vibrations (e.g., sound vibrations) generated by the one or more motor components rotating with a motor housing. 
     As shown in  FIG. 2 , the controller  40  may be in communication with additional sensors, such as a temperature sensor  70  (as shown in  FIGS. 2 and 3 ), a turbidity sensor, a humidity sensor, etc. In general, a temperature sensor is a device configured to measure the temperature of a medium such as air or water. In various embodiments, the temperature sensor  70  may be configured to detect a temperature of the air within the tub  12 . A turbidity sensor is a device configured to measure the level of particulates (often referred to as the “dirtiness”) of water or other liquids. A humidity sensor is a device configured to measure the amount of moisture in or relative humidity of a medium such as air. 
     Additionally, the controller  40  may be configured to control operation of the dishwasher  10  so as to cease operation of the wash cycle of the dishwasher under various conditions. Likewise, under various circumstances, the controller  40  may be configured to return operation of the dishwasher to the current position of the wash cycle or to a nearby position in the cycle. The controller  40  may be any type of device that can communicate with the components of the dishwasher  10  (e.g., electronically, mechanically, or otherwise). In the case of electronic communication, the controller  40  may include a memory for storing of programming, routines, and variables. In one embodiment, the controller  40  comprises one or more microprocessors or other processors configured to perform the functions described herein and may operate under the control of software. In such a regard, the controller  40  may be configured to execute any of the functions described herein according to various embodiments of the present invention. In various embodiments, the controller  40  may comprise a single consolidated device, or it may comprise a plurality of distributed devices located at various locations in the dishwasher  10 . Moreover, various operations described as being performed by the controller  40  may be performed directly by the controller  40 , or may be performed by one or more distributed computing devices in communication with the controller  40 . As a non-limiting example, certain methods, processes and/or steps as described herein for comparing actual operating characteristics and preferred operating characteristics may be carried out by one or more sensors. 
     In other embodiments, the controller  40  may be further configured to indicate or otherwise provide error message signals by either storing them in the controller  40  for later access by a user, signaling the dishwasher  10  to display or otherwise indicate the error message to the user (e.g., audibly or visually). 
     As described in greater detail herein, one or more signals received from the sensors  63 ,  70 , may be used to determine efficient operating conditions of the blower  60  and/or the heating elements. For example, upon a determination that a sound frequency and/or amplitude sensed by the vibration sensor  63  is increasing, the controller  40  may change the rotation speed of the motor  61  and/or the relative lengths of the pulses to be applied to the blower  60 . The pulsing of the blower is configured to provide additional air from outside the dishware  10  in order to help pressurize the tub  12  or to otherwise evacuate the vaporized water from the tub  12 . 
     As illustrated in  FIG. 4 , the process of optimizing the blower operation may comprise operations for adjusting the blower operation based at least in part on signals received from sensors associated with the blower  60  and/or tub  12 . As shown in  FIG. 4 , the blower  60  may be activated at operation  401 . As described herein, the blower  60  may be selectively activated (e.g., pulsed) during a drying cycle. Thus, the blower operation may be optimized during each individual time period (e.g., pulse) during which the blower  60  is activated. 
     Moreover, the blower  60  may be activated by receiving a signal from the controller  40  configured to activate the motor  61  associated with the blower  60 , and thereby operate the vent fan  62 . The process may additionally include monitoring of one or more sensors ( 402 ), such as a vibration sensor  63  associated with the blower  60  and/or a temperature sensor  70  associated with the tub  12 . As stated herein, the vibration sensor  63  may comprise an accelerometer, a microphone, or another vibration sensing device configured to monitor vibrations and sound pressure levels within the dishwasher  10 . The vibration sensor  63  may be positioned proximate (e.g., coupled to) the motor  61  of the blower  60  to sense vibrations and/or sounds generated by the motor  61 . 
     In various embodiments, operating characteristics may be received from the one or more sensors at  403 . For example, operating characteristics received from the temperature sensor  70  may be indicative of a temperature within the tub  12 . Operating characteristics received from the vibration sensor  63  may be indicative of a vibration frequency and/or vibration amplitude generated by a component of the dishwasher (e.g., sound pressure level vibrations generated by the motor  61 ). In various embodiments, data received from the sensors may be passed through one or more filters, such as a band-pass filter, to minimize the effect of signal noise on the received signals. 
     At operation  404 , the controller  40  may determine operating characteristics of the motor  61  based at least in part on the information obtained by the sensors. In various embodiments, the controller  40  may determine operating characteristics of the motor  61  based on a subset of the information obtained by the sensors. For example, the controller  40  may determine operating characteristics of the motor  61  based on information obtained from the vibration sensor  63  having a voltage maximum and/or cycle period within a predetermined range. Thus, the controller  40  may determine operating characteristics of the motor  61  based on a particular vibration source. For example, the controller  40  may determine operating characteristics based on vibrations caused by an armature having a plurality of commutator bars rotating within a motor housing, vibrations caused by an impeller having a plurality of impeller blades rotating in a pump housing, and/or vibrations caused by a fan having a plurality of rotating fan vanes. For example, a Fast Fourier Transform (FFT) may be applied to at least a portion of the received operating characteristics in order to determine operating characteristics of the motor  61 . For example, the FFT may be applied to at least a portion of the received operating characteristics to determine a fundamental frequency associated with the operating characteristics. Based on the determined fundamental frequency, a rotation speed and other characteristics of the motor  61  may be determined. 
     According to various embodiments, the FFT process comprises steps for analyzing the operating characteristics received from the vibration sensor  63  to determine a fundamental frequency. The fundamental frequency is defined as the most prominent frequency sensed in the analyzed signal (e.g., the received operating characteristics). By applying the FFT process to the signal, the fundamental frequency is manifested as the frequency having the highest amplitude, without regard to the amplitude of the original received signal. In various embodiments, upon a determination that the fundamental frequency of the operating characteristics received from the vibration sensor  63  is equal to the line frequency (the frequency of oscillations of alternating current transmitted from a power plant and received by a household), the second order frequency (the frequency having the second highest amplitude) may be used to determine a rotation speed and other characteristic of the motor  61 . For example, the line frequency in the United States is 60 Hz, and therefore upon a determination that the fundamental frequency of the operating characteristics is 60 Hz, the second order frequency as determined by the FFT process may be used to determine characteristics of the motor  61 . 
     In various embodiments, digital waveform processing may be utilized to determine various characteristics of the motor  61 . Digital waveform processing may, in various embodiments, comprise steps for minimizing the impact of lower order frequencies (e.g., second order frequencies and lower) on the operating characteristics received from the vibration sensor  63  using waveform smoothing techniques such that frequencies indicative of various characteristics of the motor  61  may be identified. The digital waveform processing may additionally comprise steps for determining the amplitude and/or the pulse-width of the resulting smoothed waveforms to determine the fundamental frequency of the received operating characteristics. 
       FIG. 5  illustrates a non-limiting example of digital waveform processing, which may comprise steps for receiving data indicative of a plurality of vibration pulses measured by the vibration sensor over a particular time period. As shown in  FIG. 5, 10  pulses (P 1 -P 10 ) are measured over a 690 microsecond time period. Each vibration pulse may be identified as a plurality of consecutive data points having an increased voltage in the data. The digital waveform processing may comprise steps for determining an average voltage measured by the vibration sensor over the particular time period (illustrated as the dashed horizontal line in  FIG. 5 ). Consecutive data points indicative of a voltage measurement higher than the average voltage measurement are thus collectively indicative of a pulse, regardless of any minor changes in voltage measured. Thus, in the illustrated example data of  FIG. 5 , although pulses P 2 , P 4 , P 5 , P 7 , and P 9  include minor changes in voltage during the pulse, these minor voltage changes do not impact the identification of the pulses. Based on the length of time the voltage exceeds the average measured voltage, the pulse width and cycle period may be determined. 
     However, in various embodiments, the fundamental frequency of the operating characteristics received from the vibration sensor  63  may be determined without additional processing such as FFT analysis and/or digital waveform processing. For example, a vibration signal having minimal or no distortion from lower order frequencies may comprise a fundamental frequency that may be determined without minimizing the impact of low order frequencies. 
     After determining the fundamental frequency of the motor  61 , the motor speed may be determined based on the fundamental frequency and various physical attributes of the motor  61  and/or other physical attributes of the blower  60 . For example, a motor comprising an armature having plurality of commutator bars configured to rotate within a motor housing may generate a plurality of vibration pulses during a single revolution equal to the number of commutator bars associated with the armature. The rotation speed of the motor is thus determined by dividing the vibration frequency of the motor by the number of commutator bars associated with the armature. Referring again to  FIG. 5  as a non-limiting example, the rotation speed of a motor comprising an armature having 5 commutator bars may be determined by dividing the determined fundamental frequency by 5. Thus, as shown in the example of  FIG. 5 , the determined cycle period is 80 microseconds, which corresponds to a frequency of 12,500 Hz. Based on the presence of 5 rotating commutator bars, the motor speed is determined to be 2500 RPM. 
     As yet another example, the rotation speed of the motor  61  may be determined based at least in part on the number of vanes of the fan  62 . Each fan vane may generate a vibration pulse during a single revolution of the fan  62 . Thus, the fundamental frequency of the operating characteristics sensed by the vibration sensor  63  may be divided by the number of vanes of the fan  62  to ascertain the rotation speed of the motor  61 . As described herein, similar analyses may be utilized to determine a rotation speed of a pump motor (e.g., a circulation pump motor  51  and/or a drain pump motor  43 ) based on the number of commutator bars of an associated armature and/or based on the number of impeller blades of an associated rotor (e.g., rotor  52  or rotor  44 ). 
     Upon identifying the operating characteristics of the motor  61 , the controller  40  may compare the identified operating characteristics with Preferred Operating Characteristics (POCs) at  405 . For example, the POCs may be indicative of a preferred vent fan rotation speed or a range of preferred vent fan rotation speeds, a preferred maximum motor noise level, a preferred maximum amount of motor vibration, and/or the like. In various embodiments, a plurality of POCs may be defined, wherein a subset of the plurality of POCs may be associated with different stages in a drying cycle of the dishwasher  10 . As will be described in greater detail herein, preferred drying characteristics may be defined in the POCs. In various embodiments, data indicative of the POCs may be stored in a memory associated with the controller  40 . The POCs may be fixed during the initial set up of the dishwasher  10  during manufacturing, or the POCs may be variable, such that one or more POCs may be modified in response to the controller  40  receiving user input via user interface  19 . In various embodiments, the POCs may be indicative of a preferred operating condition for the blower  60 . As previously indicated, a preferred operating condition may correspond with a low noise level generated by the blower  60 . 
     The comparison may comprise a determination of whether the operating characteristics satisfy the POCs at operation  406 . The determination may involve a determination whether the operating characteristics fall into an acceptable range (e.g., a defined range of preferred characteristics, a tolerance range surrounding a preferred operating characteristic value, below or equal to a maximum level, above or equal to a minimum level, and/or the like). Upon a determination that the operating characteristics satisfy the POCs, the sensors may continue to be monitored during operation  402 . The process proceeds to cycle through  402 - 407  as necessary until the drying cycle is complete. 
     Upon a determination that the operating characteristics do not satisfy the POCs, the operating signals sent to the blower  60  to operate the motor  61  may be modified in order to adjust the speed of the motor  61 . For example, a controller  40  utilizing pulse width modulation to control the speed of the motor  61  may adjust the relative lengths of the “on” and “off” pulses in order to modify the speed of the motor  61 . After adjusting the speed of the motor  61  (e.g., by transmitting the adjusted operating signal to the motor  61 ), the process returns to  402  to continue monitoring the sensors. As a non-limiting example, the operating characteristics may indicate that a motor currently operating at 3000 RPM generates a noise level exceeding a maximum noise level threshold defined in the POCs. Therefore, the controller  40  may adjust the motor speed by adjusting the transmitted operating signals such that the motor  61  begins operating at 2933 RPM or 3066 RPM and thus generates a lower sound level. The higher sound level associated with the 3000 RPM motor speed may be indicative of inefficient motor operation, and therefore by changing the motor speed, the motor may operate more efficiently. Because the motor speed may be adjusted such that the blower  60  is operating more efficiently, the drying conditions within the tub  12  may be optimized. As indicated, the process may continue to cycle through  402 - 407  until the completion of the drying cycle. 
     Moreover, in various embodiments, the controller  40  may be configured to create and maintain an optimal drying environment within the tub  12  at least in part by varying the rotational speed of the vent fan  62  and/or the operation of the heating elements. In various embodiments, the optimal drying environment within the tub  12  may correspond to an optimal environment for condensation to occur in the duct upon removal of humid air from the tub  12 . For example, the controller  40  may be configured to maintain preferred drying characteristics, such as a preferred temperature and/or a preferred humidity level, within the tub  12  by changing the speed of the blower  60  and/or by activating or deactivating the heating element. In various embodiments, the preferred drying characteristics may be defined in the POCs for the dishwasher  10 . In various embodiments, the controller  40  may receive signals from the vibration sensor  63  and/or the temperature sensor  70  indicating that the temperature and/or humidity level within the tub  12  does not correspond to the preferred drying characteristics. For example, the controller  40  may cause the vent fan  62  to change its rotation speed upon a determination that the conditions existing within the tub  12  do not correspond to optimal drying conditions. As yet another example, the controller  40  may determine that the humidity level within the tub  12  does not correspond to an optimal drying environment upon receipt of a signal from the vibration sensor  63  indicating that the sound pressure level vibrations emitted by the motor  61  correspond to a high humidity level within the tub  12 . As the humidity level within the tub  12  changes, components of the blower  60  (e.g., motor  61  and/or vent fan  62 ) may emit changing sound pressure level vibrations as the density of the air moved by the blower  60  changes. Thus, the vibration sensor  63  may be configured to detect changes in sound pressure level vibrations as the humidity within the tub  12  changes. 
     The above-described process is described in reference to a blower configured to facilitate drying of dishware by removing humid air from a dishwasher tub, and in reference to  FIG. 4 . However, it should be understood that a similar process may be utilized to control other powered dishwasher components (e.g., circulation pump  50 , drain pump  42 ). In various embodiments, the vibration sensor  63  may be used to monitor the operating characteristics of a plurality of dishwasher components (e.g., blower  60 , drain pump  42 , and/or circulation pump  50 ). In certain embodiments, a plurality of vibration sensors may be utilized to monitor a plurality of dishwasher components. For example, as shown in  FIG. 6 , a vibration sensor  53  similar to vibration sensor  63  may be configured to sense operating characteristics of the circulation pump  50 . The vibration sensor  53  may be located in contact with the controller  40 , or proximate and/or in contact with the circulation pump  50  and/or circulation pump motor  51 , and may be configured to monitor vibrations emitted by the circulation pump motor  51  and/or a circulation pump rotor  52  (e.g., an impeller having a plurality of blades (not shown)) configured to move water through the circulation pump  50 . 
     Similarly, as illustrated in  FIG. 7 , a vibration sensor  45  similar to vibration sensor  63  may be configured to sense operating characteristics of the drain pump  42 . The vibration sensor  45  may be located in contact with the controller  40 , or proximate and/or in contact with drain pump  42  and/or drain pump motor  43 . The vibration sensor  45  may be configured to monitor vibrations emitted by the drain pump motor  43  and/or a drain pump rotor  44  (e.g., an impeller having a plurality of blades (not shown)) configured to move water through the drain pump  42 . 
     As described in reference to  FIGS. 7 and 8 , the controller  40  may be configured to cause the circulation pump motor  51  and/or the drain pump motor  43  to operate at a particular speed based at least in part on signals received from vibration sensor  53  and/or vibration sensor  45 . In various embodiments, the signals received from vibration sensor  53  may be indicative of operating characteristics of the circulation pump  50 , such as an operating frequency and/or pump rotation speed, and/or the signals received from vibration sensor  45  may be indicative of operating characteristics of the drain pump  42 , such as an operating frequency and/or pump rotation speed. 
     Referring now to  FIG. 8 , the process of optimizing the circulation pump operation may comprise operations for adjusting the circulation pump operation based at least in part on signals received from sensors associated with the circulation pump  50  and/or tub  12 . As shown in  FIG. 8 , the circulation pump  50  may be activated at operation  701 . In various embodiments, the circulation pump  50  may be selectively activated to pump water throughout the dishwasher  10  during a cleaning cycle. 
     Moreover, the circulation pump  50  may be activated by receiving a signal from the controller  40  configured to activate the motor  51  associated with the circulation pump  50 , and thereby operate the rotor  52  (e.g., an impeller). The process may additionally include monitoring of one or more sensors ( 702 ), such as a vibration sensor  53  associated with the circulation pump  50  and/or a water level sensor associated with the tub  12 . Like vibration sensor  63 , the vibration sensor  53  may comprise an accelerometer, a microphone, or another vibration sensing device configured to monitor vibrations and sound pressure levels within the dishwasher  10 . 
     In various embodiments, operating characteristics of the circulation pump  50  may be received from the one or more sensors at  703 . For example, operating characteristics received from the water level sensor may be indicative of a water level existing in a bottom portion of the tub  12 . Operating characteristics received from the vibration sensor  53  may be indicative of a vibration frequency and/or vibration amplitude generated by a component of the dishwasher (e.g., sound pressure level vibrations generated by the motor  51 ). In various embodiments, data received from the sensors may be passed through one or more filters, such as a band-pass filter, to minimize the effect of signal noise on the received signals. 
     At  704 , the controller  40  may determine operating characteristics of the motor  51  based at least in part on the information obtained by the sensors. Such operating characteristics may be determined using processes similar to those described above in reference to the vent fan motor  61 . For example, a FFT and/or digital waveform processing may be applied to at least a portion of the received operating characteristics in order to determine the rotation speed and/or other operating characteristics of the motor  51 . However, in various embodiments, the fundamental frequency of the received operating characteristics may be determined without applying a FFT and/or digital waveform processing. For example, the FFT may be applied to at least a portion of the operating characteristics received from the vibration sensor  53  to determine a fundamental frequency associated with the received operating characteristics. Based on the determined fundamental frequency, a rotation speed and other characteristics of the motor  51  may be determined. As detailed above in reference to  FIG. 4 , the rotation speed of the motor  51  may be determined based at least in part on the fundamental frequency and the number of commutator bars associated with the armature of the motor  51 . Moreover, in various embodiments, the rotation speed of the motor  51  may be determined based at least in part on the fundamental frequency and the number of impeller blades associated with the rotor  52 . As previously indicated, each impeller blade may generate a vibration pulse during a single rotation of the impeller. Thus, the rotation speed of the circulation pump motor  51  may be determined by dividing the fundamental frequency by the number of impeller blades. As a non-limiting example, for a circulation pump comprising an impeller having 15 blades, the rotation speed of the circulation pump motor may be determined by dividing the fundamental frequency by 15. 
     Upon identifying the operating characteristics of the motor  51 , the controller  40  may compare the identified operating characteristics of the circulation pump  50  with preferred operating characteristics for the circulation pump  50  at  705 . For example, the preferred operating characteristics for the circulation pump  50  may be indicative of a preferred rotor (e.g., impeller) rotation speed or a range of preferred rotor rotation speeds, a preferred maximum motor noise level, a preferred maximum amount of motor vibration, and/or the like. In various embodiments, a plurality of preferred operating characteristics for the circulation pump  50  may be defined for the circulation pump  50 , wherein a subset of the plurality of preferred operating characteristics for the circulation pump  50  may be associated with different stages in a washing cycle of the dishwasher  10 . In various embodiments, data indicative of the preferred operating characteristics for the circulation pump  50  for the circulation pump  50  may be stored as a portion of the POCs discussed herein in a memory associated with the controller  40 . 
     The comparison may comprise a determination of whether the operating characteristics satisfy the preferred operating characteristics for the circulation pump  50  at operation  706 . The determination may involve a determination whether the operating characteristics for the circulation pump  50  fall into an acceptable range (e.g., a defined range of preferred characteristics, a tolerance range surrounding a preferred operating characteristic value, below or equal to a maximum level, above or equal to a minimum level, and/or the like). Upon a determination that the operating characteristics satisfy the preferred operating characteristics for the circulation pump  50 , the sensors (e.g., vibration sensor  53 ) may continue to be monitored during operation  702 . The process proceeds to cycle through  702 - 707  as necessary until the drying cycle is complete. 
     Upon a determination that the operating characteristics of the circulation pump  50  do not satisfy the preferred operating characteristics for the circulation pump  50 , the operating signals sent to the circulation pump  50  to operate the circulation pump motor  51  may be modified in order to adjust the speed of the motor  51 . After adjusting the speed of the motor  51  (e.g., by transmitting the adjusted operating signal to the motor  51 ), the process returns to  702  to continue monitoring the sensors. As a non-limiting example, it may be determined that the circulation pump  50  emits a higher frequency and/or higher volume sound pressure level during time periods in which the circulation pump  50  is operating inefficiently (e.g., pumping air instead of water). Thus, the preferred operating characteristics for the circulation pump  50  may comprise a maximum sound frequency and/or sound volume that correspond with inefficient circulation pump operation. Upon a determination that the operating characteristics of the circulation pump  50 , as sensed by the vibration sensor  53 , exceeds the maximum noise frequency and/or volume, the controller  40  may slow the speed of the circulation pump  50  to avoid potentially inefficient operation. 
     Similarly, as illustrated in  FIG. 9 , the process of optimizing the drain pump operation may comprise operations for adjusting the drain pump operation based at least in part on signals received from sensors associated with the drain pump  42  and/or tub  12 . As shown in  FIG. 9 , the drain pump  42  may be activated at operation  801 . For example, the drain pump  42  may be activated by receiving a signal from the controller  40  configured to activate the motor  43  associated with the drain pump  42 , and thereby operate the rotor  44  (e.g., impeller). The process may additionally include monitoring of one or more sensors ( 802 ), such as a vibration sensor  45  associated with the drain pump  42  and/or a water level sensor associated with the tub  12  and/or the sump  14 . Like sensors  63  and  53 , the vibration sensor  45  may comprise an accelerometer, a microphone, or another vibration sensing device configured to monitor vibrations and sound pressure levels within the dishwasher  10 . 
     In various embodiments, operating characteristics of the drain pump  42  may be received from the one or more sensors at  803 . The operating characteristics received from the vibration sensor  45  may be indicative of a vibration frequency and/or vibration amplitude generated by a component of the dishwasher (e.g., sound pressure level vibrations generated by the motor  43 ). In various embodiments, data received from the sensors may be passed through one or more filters, such as a band-pass filter, to minimize the effect of signal noise on the received signals. 
     At  804 , the controller  40  may determine operating characteristics of the motor  43  based at least in part on the information obtained by the sensors. Such operating characteristics may be determined using processes similar to those described above in reference to the vent fan motor  61 . For example, a Fast Fourier Transform (FFT) and/or digital waveform processing may be applied to at least a portion of the received operating characteristics in order to determine the rotation speed and/or other operating characteristics of the motor  43 . For example, the FFT may be applied to at least a portion of the operating characteristics received from the vibration sensor  45  to determine a fundamental frequency associated with the received operating characteristics. Based on the determined fundamental frequency, a rotation speed and other characteristics of the motor  43  may be determined. As detailed above in reference to  FIG. 4 , the rotation speed of the motor  43  may be determined based at least in part on the fundamental frequency and the number of commutator bars associated with the armature of the motor  43 . Moreover, in various embodiments, the rotation speed of the motor  43  may be determined based at least in part on the fundamental frequency and the number of impeller blades associated with the rotor  44 . As previously indicated, each impeller blade may generate a vibration pulse during a single rotation of the impeller. Thus, the rotation speed of the drain pump motor  43  may be determined by dividing the fundamental frequency by the number of impeller blades. 
     Upon identifying the operating characteristics of the motor  43 , the controller  40  may compare the identified operating characteristics of the drain pump  42  with preferred operating characteristics for the drain pump  42  at  805 . For example, the preferred operating characteristics for the drain pump  42  may be indicative of a preferred rotor rotation speed or a range of preferred rotor rotation speeds, a preferred maximum motor noise level, a preferred maximum amount of motor vibration, and/or the like. In various embodiments, a plurality of preferred operating characteristics for the drain pump  42  may be defined for the drain pump  42 , wherein a subset of the plurality of preferred operating characteristics for the drain pump  42  may be associated with different stages in a washing cycle of the dishwasher  10 . In various embodiments, data indicative of the preferred operating characteristics for the drain pump  42  may be stored as a portion of the discussed POCs in a memory associated with the controller  40 . 
     The comparison may comprise a determination of whether the operating characteristics of the drain pump  42  satisfy the preferred operating characteristics for the drain pump  42  at operation  806 . The determination may involve a determination whether the operating characteristics fall into an acceptable range (e.g., a defined range of preferred characteristics, a tolerance range surrounding a preferred operating characteristic value, below or equal to a maximum level, above or equal to a minimum level, and/or the like). Upon a determination that the operating characteristics satisfy the preferred operating characteristics for the drain pump  42 , the sensors may continue to be monitored during operation  802 . The process proceeds to cycle through  802 - 807  as necessary. 
     Upon a determination that the operating characteristics of the drain pump  42  do not satisfy the preferred operating characteristics for the drain pump  42 , the operating signals sent to the drain pump  42  to operate the motor  43  may be modified in order to adjust the speed of the motor  43 . After adjusting the speed of the motor  43  (e.g., by transmitting the adjusted operating signal to the motor  43 ), the process returns to  802  to continue monitoring the sensors. For example, it may be determined that the drain pump  42  emits a higher frequency and/or higher volume sound pressure level during time periods in which the drain pump  42  is operating inefficiently (e.g., pumping “dry” air instead of water). Thus, the preferred operating characteristics for the drain pump  42  may comprise a maximum sound frequency and/or sound volume that correspond with inefficient drain pump operation. Upon a determination that the operating characteristics of the drain pump  42 , as sensed by the vibration sensor  45 , exceeds the maximum noise frequency and/or volume, the controller  40  may slow the speed of the drain pump  42  to avoid potentially inefficient operation. 
     Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.