METHOD OF USING TURBIDITY MEASUREMENTS TO IMPROVE PERFORMANCE OF A WASHING MACHINE APPLIANCE

A washing machine appliance includes a wash basket that is rotatably mounted within a wash tub. A water supply is provided for selectively adding wash fluid to the wash tub, a motor assembly is mechanically coupled to the wash basket for selectively rotating the wash basket, and a turbidity sensor is positioned within the wash fluid. A controller is configured to operate the water supply to dispense a target volume of the wash fluid, perform an additive mixing cycle to agitate wash additive within the target volume of the wash fluid, obtain a first turbidity measurement, perform an agitation cycle with the target volume of the wash fluid, obtain a second turbidity measurement, and complete a wash cycle at the a wash cycle intensity determined a based at least in part on the first turbidity and the second turbidity.

FIELD OF THE INVENTION

The present subject matter relates generally to washing machine appliances, or more specifically, to methods for using turbidity measurements to improve the wash performance in a washing machine appliance.

BACKGROUND OF THE INVENTION

Washing machine appliances generally include a tub for containing water or wash fluid, e.g., water and detergent, bleach, and/or other wash additives. A basket is rotatably mounted within the tub and defines a wash chamber for receipt of articles for washing. During normal operation of such washing machine appliances, the wash fluid is directed into the tub and onto articles within the wash chamber of the basket. The basket or an agitation element can rotate at various speeds to agitate articles within the wash chamber, to wring wash fluid from articles within the wash chamber, etc. During a spin or drain cycle, a drain pump assembly may operate to discharge water from within sump.

Conventional washing machines may permit the user to select a soil level associated with a particular wash cycle, e.g., with higher soil selections resulting in a longer and more aggressive agitation process to properly clean the clothes. However, users often select the incorrect soil level or do not know the soil level for a particular load of clothes. Accordingly, washing machines commonly over-wash clothes, resulting in unnecessary wear on clothes and longer cycle times. By contrast, if the selected soil level is low and the clothes are very dirty, the cleaning cycle may under-wash the clothes, leaving behind soils and resulting in user dissatisfaction.

Accordingly, a washing machine appliance with improved wash performance is desirable. More specifically, a method for detecting soil levels and selecting an appropriate wash cycle parameters while reducing cycle time and improving user satisfaction would be particularly beneficial.

BRIEF DESCRIPTION OF THE INVENTION

In one exemplary embodiment, a washing machine appliance is provided including a wash tub positioned within a cabinet, a wash basket rotatably mounted within the wash tub and defining a wash chamber configured for receiving a load of clothes, a water supply for selectively adding wash fluid to the wash tub, a sump positioned proximate a bottom of the wash tub for collecting the wash fluid, a turbidity sensor positioned within the wash fluid, a motor assembly mechanically coupled to the wash basket for selectively rotating the wash basket, and a controller operably coupled to the water supply and the motor assembly. The controller is configured to operate the water supply to dispense a target volume of the wash fluid into the wash tub, operate the motor assembly to perform an additive mixing cycle to agitate wash additive within the target volume of the wash fluid, obtain a first turbidity of the wash fluid using the turbidity sensor, operate the motor assembly to perform an agitation cycle with the target volume of the wash fluid, obtain a second turbidity of the wash fluid using the turbidity sensor, determine a wash cycle intensity based at least in part on the first turbidity and the second turbidity, and complete a wash cycle at the determined wash cycle intensity.

In another exemplary embodiment, a method of operating a washing machine appliance is provided. The washing machine appliance includes a wash basket rotatably mounted within a wash tub, a water supply for selectively adding wash fluid to the wash tub, a turbidity sensor positioned within the wash fluid, and a motor assembly mechanically coupled to the wash basket for selectively rotating the wash basket. The method includes operating the water supply to dispense a target volume of the wash fluid into the wash tub, operating the motor assembly to perform an additive mixing cycle to agitate wash additive within the target volume of the wash fluid, obtaining a first turbidity of the wash fluid using the turbidity sensor, operating the motor assembly to perform an agitation cycle with the target volume of the wash fluid, obtaining a second turbidity of the wash fluid using the turbidity sensor, determining a wash cycle intensity based at least in part on the first turbidity and the second turbidity, and completing a wash cycle at the determined wash cycle intensity.

DETAILED DESCRIPTION

FIGS.1through3illustrate an exemplary embodiment of a vertical axis washing machine appliance100. Specifically,FIGS.1and2illustrate perspective views of washing machine appliance100in a closed and an open position, respectively.FIG.3provides a side cross-sectional view of washing machine appliance100. Washing machine appliance100generally defines a vertical direction V, a lateral direction L, and a transverse direction T, each of which is mutually perpendicular, such that an orthogonal coordinate system is generally defined.

While described in the context of a specific embodiment of vertical axis washing machine appliance100, it should be appreciated that vertical axis washing machine appliance100is provided by way of example only. It will be understood that aspects of the present subject matter may be used in any other suitable washing machine appliance, such as a horizontal axis washing machine appliance. Indeed, modifications and variations may be made to washing machine appliance100, including different configurations, different appearances, and/or different features while remaining within the scope of the present subject matter.

Washing machine appliance100has a cabinet102that extends between a top portion104and a bottom portion106along the vertical direction V, between a first side (left) and a second side (right) along the lateral direction L, and between a front and a rear along the transverse direction T. As best shown inFIG.3, a wash tub108is positioned within cabinet102, defines a wash chamber110, and is generally configured for retaining wash fluids during an operating cycle. Washing machine appliance100further includes a primary dispenser or dispensing assembly112(FIG.2) for dispensing wash fluid into wash tub108.

In addition, washing machine appliance100includes a wash basket114that is positioned within wash tub108and generally defines an opening116for receipt of articles for washing. More specifically, wash basket114is rotatably mounted within wash tub108such that it is rotatable about an axis of rotation A. According to the illustrated embodiment, the axis of rotation A is substantially parallel to the vertical direction V. In this regard, washing machine appliance100is generally referred to as a “vertical axis” or “top load” washing machine appliance100. However, it should be appreciated that aspects of the present subject matter may be used within the context of a horizontal axis or front load washing machine appliance as well.

As illustrated, cabinet102of washing machine appliance100has a top panel118. Top panel118defines an opening (FIG.2) that coincides with opening116of wash basket114to permit a user access to wash basket114. Washing machine appliance100further includes a door120which is rotatably mounted to top panel118to permit selective access to opening116. In particular, door120selectively rotates between the closed position (as shown inFIGS.1and3) and the open position (as shown inFIG.2). In the closed position, door120inhibits access to wash basket114. Conversely, in the open position, a user can access wash basket114. A window122in door120permits viewing of wash basket114when door120is in the closed position, e.g., during operation of washing machine appliance100. Door120also includes a handle124that, e.g., a user may pull and/or lift when opening and closing door120. Further, although door120is illustrated as mounted to top panel118, door120may alternatively be mounted to cabinet102or any other suitable support.

As best shown inFIGS.2and3, wash basket114further defines a plurality of perforations126to facilitate fluid communication between an interior of wash basket114and wash tub108. In this regard, wash basket114is spaced apart from wash tub108to define a space for wash fluid to escape wash chamber110. During a spin cycle, wash fluid within articles of clothing and within wash chamber110is urged through perforations126wherein it may collect in a sump128defined by wash tub108. Washing machine appliance100further includes a pump assembly130(FIG.3) that is located beneath wash tub108and wash basket114for gravity assisted flow when draining wash tub108.

An impeller or agitation element132(FIG.3), such as a vane agitator, impeller, auger, oscillatory basket mechanism, or some combination thereof is disposed in wash basket114to impart an oscillatory motion to articles and liquid in wash basket114. More specifically, agitation element132extends into wash basket114and assists agitation of articles disposed within wash basket114during operation of washing machine appliance100, e.g., to facilitate improved cleaning. In different embodiments, agitation element132includes a single action element (i.e., oscillatory only), a double action element (oscillatory movement at one end, single direction rotation at the other end) or a triple action element (oscillatory movement plus single direction rotation at one end, single direction rotation at the other end). As illustrated inFIG.3, agitation element132and wash basket114are oriented to rotate about axis of rotation A (which is substantially parallel to vertical direction V).

As best illustrated inFIG.3, washing machine appliance100includes a drive assembly or motor assembly138in mechanical communication with wash basket114to selectively rotate wash basket114(e.g., during an agitation or a rinse cycle of washing machine appliance100). In addition, motor assembly138may also be in mechanical communication with agitation element132. In this manner, motor assembly138may be configured for selectively rotating or oscillating wash basket114and/or agitation element132during various operating cycles of washing machine appliance100.

More specifically, motor assembly138may generally include one or more of a drive motor140and a transmission assembly142, e.g., such as a clutch assembly, for engaging and disengaging wash basket114and/or agitation element132. According to the illustrated embodiment, drive motor140is a brushless DC electric motor, e.g., a pancake motor. However, according to alternative embodiments, drive motor140may be any other suitable type or configuration of motor. For example, drive motor140may be an AC motor, an induction motor, a permanent magnet synchronous motor, or any other suitable type of motor. In addition, motor assembly138may include any other suitable number, types, and configurations of support bearings or drive mechanisms.

Referring still toFIGS.1through3, a control panel150with at least one input selector152(FIG.1) extends from top panel118. Control panel150and input selector152collectively form a user interface input for operator selection of machine cycles and features. A display154of control panel150indicates selected features, operation mode, a countdown timer, and/or other items of interest to appliance users regarding operation.

Operation of washing machine appliance100is controlled by a controller or processing device156that is operatively coupled to control panel150for user manipulation to select washing machine cycles and features. In response to user manipulation of control panel150, controller156operates the various components of washing machine appliance100to execute selected machine cycles and features. According to an exemplary embodiment, controller156may include a memory and microprocessor, such as a general or special purpose microprocessor operable to execute programming instructions or micro-control code associated with methods described herein. Alternatively, controller156may be constructed without using a microprocessor, e.g., using a combination of discrete analog and/or digital logic circuitry (such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, and the like) to perform control functionality instead of relying upon software. Control panel150and other components of washing machine appliance100may be in communication with controller156via one or more signal lines or shared communication busses.

During operation of washing machine appliance100, laundry items are loaded into wash basket114through opening116, and washing operation is initiated through operator manipulation of input selectors152. Wash basket114is filled with water and detergent and/or other fluid additives via primary dispenser112. One or more valves can be controlled by washing machine appliance100to provide for filling wash tub108and wash basket114to the appropriate level for the amount of articles being washed and/or rinsed. By way of example for a wash mode, once wash basket114is properly filled with fluid, the contents of wash basket114can be agitated (e.g., with agitation element132as discussed previously) for washing of laundry items in wash basket114.

Referring again toFIGS.2and3, dispensing assembly112of washing machine appliance100will be described in more detail. As explained briefly above, dispensing assembly112may generally be configured to dispense wash fluid to facilitate one or more operating cycles or phases of an operating cycle (e.g., such as a wash cycle or a rinse cycle). The terms “wash fluid” and the like may be used herein to generally refer to a liquid used for washing and/or rinsing clothing or other articles. For example, the wash fluid is typically made up of water that may include other additives such as detergent, fabric softener, bleach, or other suitable treatments (including combinations thereof). More specifically, the wash fluid for a wash cycle may be a mixture of water, detergent, and/or other additives, while the wash fluid for a rinse cycle may be water only.

As best shown schematically inFIG.3, dispensing assembly112may generally include a bulk storage tank or bulk reservoir158and a dispenser box160. More specifically, bulk reservoir158may be positioned under top panel118and defines an additive reservoir for receiving and storing wash additive. More specifically, according to the illustrated embodiment, bulk reservoir158may contain a bulk volume of wash additive (such as detergent or other suitable wash additives) that is sufficient for a plurality of wash cycles of washing machine appliance100, such as no less than twenty wash cycles, no less than fifty wash cycles, etc. As a particular example, bulk reservoir158is configured for containing no less than twenty fluid ounces, no less than three-quarters of a gallon, or about one gallon of wash additive.

As will be described in detail below, dispensing assembly112may include features for drawing wash additive from bulk reservoir158and mixing it with water prior to directing the mixture into wash tub108to facilitate a cleaning operation. By contrast, dispensing assembly112is also capable of dispensing water only. Thus, dispensing assembly112may automatically dispense the desired amount of water with or without a desired amount of wash additive such that a user can avoid filling dispenser box160with detergent before each operation of washing machine appliance100.

For example, as best shown inFIG.3, washing machine appliance100includes an aspirator assembly162, which is a Venturi-based dispensing system that uses a flow of water to create suction within a Venturi tube to draw in wash additive from bulk reservoir158which mixes with the water and is dispensed into wash tub108as a concentrated wash fluid preferably having a target volume of wash additive. After the target volume of wash additive is dispensed into wash tub108, additional water may be provided into wash tub108as needed to fill to the desired wash volume. It should be appreciated that the target volume may be preprogrammed in controller156according to the selected operating cycle or parameters, may be set by a user, or may be determined in any other suitable manner.

As illustrated, aspirator assembly162includes a Venturi pump164that is fluidly coupled to both a water supply conduit166and a suction line168. As illustrated, water supply conduit166may provide fluid communication between a water supply source170(such as a municipal water supply) and a water inlet of Venturi pump164. In addition, washing machine appliance100includes a water fill valve or water control valve172which is operably coupled to water supply conduit166and is communicatively coupled to controller156. In this manner, controller156may regulate the operation of water control valve172to regulate the amount of water that passes through aspirator assembly162and into wash tub108.

In addition, suction line168may provide fluid communication between bulk reservoir158and Venturi pump164(e.g., via a suction port defined on Venturi pump164). Notably, as a flow of water is supplied through Venturi pump164to wash tub108, the flowing water creates a negative pressure within suction line168. This negative pressure may draw in wash additive from bulk reservoir158. When certain conditions exist, the amount of wash additive dispensed is roughly proportional to the amount of time water is flowing through Venturi pump164.

Referring still toFIG.3, aspirator assembly162may further include a suction valve174that is operably coupled to suction line168to control the flow of wash additive through suction line168when desired. For example, suction valve174may be a solenoid valve that is communicatively coupled with controller156. Controller156may selectively open and close suction valve174to allow wash additive to flow from bulk reservoir158through additive suction valve174. For example, during a rinse cycle where only water is desired, suction valve174may be closed to prevent wash additive from being dispensed through suction valve174. In some embodiments, suction valve174is selectively controlled based on at least one of the selected wash cycle, the soil level of the articles to be washed, and the article type. According to still other embodiments, no suction valve174is needed at all and alternative means for preventing the flow of wash additive may be used or other water regulating valves may be used to provide water into wash tub108.

Washing machine appliance100, or more particularly, dispensing assembly112, generally includes a discharge nozzle176for directing a flow of wash fluid (e.g., identified herein generally by reference numeral178) into wash chamber108. In this regard, discharge nozzle176may be positioned above wash tub proximate a rear of opening116defined through top panel118. Dispensing assembly112may be regulated by controller156to discharge wash fluid178through discharge nozzle176at the desired flow rates, volumes, and/or detergent concentrations to facilitate various operating cycles, e.g., such as wash or rinse cycles.

Although water supply conduit166, water supply source170, discharge nozzle176, and water control valve172are all described and illustrated herein in the singular form, it should be appreciated that these terms may be used herein generally to describe a supply plumbing for providing hot and/or cold water into wash chamber110. In this regard, water supply conduit166may include separate conduits for receiving hot and cold water, respectively. Similarly, water supply source170may include both hot- and cold-water supplies regulated by dedicated valves. In addition, washing machine appliance100may include one or more pressure sensors (not shown) for detecting the amount of water and or clothes within wash tub108. For example, the pressure sensor may be operably coupled to a side of tub108for detecting the weight of wash tub108, which controller156may use to determine a volume of water in wash chamber110and a subwasher load weight.

After wash tub108is filled and the agitation phase of the wash cycle is completed, wash basket114can be drained, e.g., by drain pump assembly130. Laundry articles can then be rinsed by again adding fluid to wash basket114depending on the specifics of the cleaning cycle selected by a user. The impeller or agitation element132may again provide agitation within wash basket114. One or more spin cycles may also be used as part of the cleaning process. In particular, a spin cycle may be applied after the wash cycle and/or after the rinse cycle in order to wring wash fluid from the articles being washed. During a spin cycle, wash basket114is rotated at relatively high speeds to help wring fluid from the laundry articles through perforations126. During or prior to the spin cycle, drain pump assembly130may operate to discharge wash fluid from wash tub108, e.g., to an external drain. After articles disposed in wash basket114are cleaned and/or washed, the user can remove the articles from wash basket114, e.g., by reaching into wash basket114through opening116.

Referring now specifically toFIG.3, washing machine appliance100may include a sensor assembly180that includes one or more sensors for providing useful information regarding a particular load or operating cycle of the appliance. This information may be used for improved appliance performance, as described in more detail herein. For example, sensor assembly180may include a turbidity sensor182, e.g., for monitoring the contaminant level or soil level of wash fluid178, e.g., in order to determine the cleanliness of the clothes or to determine appropriate rinse parameters.

According to the illustrated embodiment, sensor assembly180and turbidity sensor182may be mounted within sump128where it is capable of obtaining accurate reading of wash fluid178within wash tub108. According to still other embodiments, turbidity sensor182may alternatively be positioned within a drain line or in drain pump assembly130, within a recirculation line or assembly, or at any other location where it is in contact with collected wash fluid178.

According to an example embodiment, turbidity sensor182may operate by using an emitter to emit a beam of light that is passed through wash fluid178and detecting the beam of light using a receiver. In this manner, the turbidity of wash fluid178may be estimated based on the distortion of the beam of light. Although turbidity sensor182is illustrated herein as including an emitter and receiver for generating and receiving a beam of light, it should be appreciated that this is only one exemplary embodiment. Any other suitable type or configuration of turbidity sensor may be used while remaining within the scope of the present subject matter. Other sensor configurations are possible and within the scope of the present subject matter.

In addition, sensor assembly180may be used to monitor the wash process using any other suitable sensors. For example, as illustrated, sensor assembly180may include an auxiliary sensor184that is positioned in sump128and is configured for monitoring other suitable parameters or conditions of the wash fluid178. For example, auxiliary sensor184may be a conductivity sensor for measuring the electrical conductivity of the wash fluid178. In addition, or alternatively, auxiliary sensor184may be a pH sensor for measuring the pH of the wash fluid178. The conductivity and pH may be related to the conditions of the wash fluid178and may be used to facilitate an improved rinse cycle, as described herein with respect to the use of turbidity measurements.

Referring still toFIG.1, a schematic diagram of an external communication system190will be described according to an exemplary embodiment of the present subject matter. In general, external communication system190is configured for permitting interaction, data transfer, and other communications between washing machine appliance100and one or more external devices. For example, this communication may be used to provide and receive operating parameters, user instructions or notifications, performance characteristics, user preferences, or any other suitable information for improved performance of washing machine appliance100. In addition, it should be appreciated that external communication system190may be used to transfer data or other information to improve performance of one or more external devices or appliances and/or improve user interaction with such devices.

For example, external communication system190permits controller156of washing machine appliance100to communicate with a separate device external to washing machine appliance100, referred to generally herein as an external device192. As described in more detail below, these communications may be facilitated using a wired or wireless connection, such as via a network194. In general, external device192may be any suitable device separate from washing machine appliance100that is configured to provide and/or receive communications, information, data, or commands from a user. In this regard, external device192may be, for example, a personal phone, a smartphone, a tablet, a laptop or personal computer, a wearable device, a smart home system, or another mobile or remote device.

In addition, a remote server196may be in communication with washing machine appliance100and/or external device192through network194. In this regard, for example, remote server196may be a cloud-based server196, and is thus located at a distant location, such as in a separate state, country, etc. According to an exemplary embodiment, external device192may communicate with a remote server196over network194, such as the Internet, to transmit/receive data or information, provide user inputs, receive user notifications or instructions, interact with or control washing machine appliance100, etc. In addition, external device192and remote server196may communicate with washing machine appliance100to communicate similar information.

In general, communication between washing machine appliance100, external device192, remote server196, and/or other user devices or appliances may be carried using any type of wired or wireless connection and using any suitable type of communication network, non-limiting examples of which are provided below. For example, external device192may be in direct or indirect communication with washing machine appliance100through any suitable wired or wireless communication connections or interfaces, such as network194. For example, network194may include one or more of a local area network (LAN), a wide area network (WAN), a personal area network (PAN), the Internet, a cellular network, any other suitable short- or long-range wireless networks, etc. In addition, communications may be transmitted using any suitable communications devices or protocols, such as via Wi-Fi®, Bluetooth®, Zigbee®, wireless radio, laser, infrared, Ethernet type devices and interfaces, etc. In addition, such communication may use a variety of communication protocols (e.g., TCP/IP, HTTP, SMTP, FTP), encodings or formats (e.g., HTML, XML), and/or protection schemes (e.g., VPN, secure HTTP, SSL).

External communication system190is described herein according to an exemplary embodiment of the present subject matter. However, it should be appreciated that the exemplary functions and configurations of external communication system190provided herein are used only as examples to facilitate description of aspects of the present subject matter. System configurations may vary, other communication devices may be used to communicate directly or indirectly with one or more associated appliances, other communication protocols and steps may be implemented, etc. These variations and modifications are contemplated as within the scope of the present subject matter.

While described in the context of a specific embodiment of vertical axis washing machine appliance100, using the teachings disclosed herein it will be understood that vertical axis washing machine appliance100is provided by way of example only. Other washing machine appliances having different configurations, different appearances, and/or different features may also be utilized with the present subject matter as well, e.g., horizontal axis washing machine appliances. In addition, aspects of the present subject matter may be utilized in a combination washer/dryer appliance.

Now that the construction of washing machine appliance100and the configuration of controller156according to exemplary embodiments have been presented, an exemplary method200of operating a washing machine appliance will be described. Although the discussion below refers to the exemplary method200of operating washing machine appliance100, one skilled in the art will appreciate that the exemplary method200is applicable to the operation of a variety of other washing machine appliances, such as horizontal axis washing machine appliances. In exemplary embodiments, the various method steps as disclosed herein may be performed by controller156or a separate, dedicated controller.

Referring now toFIG.4, method200includes, at step210, operating a water supply to dispense a target volume of wash fluid into a wash tub of a washing machine appliance. For example, using washing machine appliance100as an example, the wash cycle may include operating a water supply (e.g., via water control valve172) to add wash fluid (e.g., water, detergent, and/or other additives) into wash tub108. As used herein, the “target volume” of wash fluid may be used to refer generally to the volume of wash fluid desirable for the performance of a complete wash cycle. In this regard, for example, the target volume of wash fluid may be the maximum amount of wash fluid dispensed into wash tub108during the agitation phase or wash phase of an operating cycle. According to exemplary embodiments, the target volume may be set by the user, determined based on cycle parameters, or may be determined using a load sensing procedure. In addition, it should be appreciated that this target volume may be measured and represented using any suitable unit of measure, e.g., such as inches of wash fluid, total volume in gallons, etc.

Step220may generally include operating a motor assembly to perform an additive mixing cycle to agitate wash additive within the target volume of wash fluid. In this regard, a wash additive may be dispensed along with wash fluid178, e.g., via a bulk reservoir158and aspirator assembly162. As explained in more detail herein, it may be desirable to obtain a turbidity measurement of the wash fluid within wash tub108after the wash additive is added. More specifically, in order to ensure the wash additive within the target volume of wash fluid has been properly mixed or dispersed within the target volume, the additive mixing cycle may be a cursory agitation of the wash fluid prior to the agitation cycle, described in more detail below.

Step230may include obtaining a first turbidity measurement of the wash fluid using a turbidity sensor. For example, turbidity sensor182may be positioned within sump128of wash tub108and may be used to obtain a first turbidity after the additive mixing cycle has been completed. According to still other embodiments, the first turbidity may be obtained during the additive mixing cycle, may be an average of turbidity measurements obtained during an additive mixing cycle, or may be obtained in any other suitable manner.

Step240may generally include operating the motor assembly to perform an agitation cycle with the target volume of the wash fluid. In this regard, after obtaining the first turbidity measurement, and with the target volume of wash fluid still present within wash tub108, motor assembly138may perform an agitation/wash cycle to clean the articles of clothing present within wash basket114. It should be appreciated that the agitation cycle parameters may be determined in any suitable manner for achieving the desired cleanliness of the articles of clothing.

As explained briefly above, the additive mixing cycle is generally intended to mix, dilute, or distribute wash additive within wash fluid178in wash tub108. The additive mixing cycle is not intended to agitate clothes to the extent that soils are extracted and distributed throughout wash fluid178. Accordingly, the first turbidity measured at step230may be a turbidity associated with or resulting from a wash additive within the dispensed water. After the agitation cycle has been completed, step250may include obtaining a second turbidity of the wash fluid using the turbidity sensor. In contrast to the first turbidity, the second turbidity measurement may be affected by both wash additive within wash fluid178and soils that have been extracted from the clothes.

Notably, the second turbidity may be obtained after an agitation cycle that has been performed with the target volume of wash fluid. In this manner, by obtaining both the first turbidity and the second turbidity at the same wash fluid level, errors that may be introduced due to differences in detergent concentration may be reduced or eliminated altogether. For example, if the first turbidity were obtained when the wash fluid volume is lower than the wash fluid volume when the second turbidity was obtained, first turbidity may have a higher detergent concentration since the water volume is less, even though the same amount of detergent may be present. In sum, obtaining the first turbidity and the second turbidity at the same wash fluid volume may be desirable to more accurately determine the amount of turbidity associated with soils within the load of clothes. Moreover, although the turbidity measurements are described herein as being obtained when the wash fluid reaches a target volume associated with a final fill amount for a wash cycle, it should be appreciated that according to alternative embodiments, these measurements may be obtained at any other suitable wash fluid volume. For example, the turbidity reading could be taken at an initial lower fill volume (lower than the final fill volume) to increase the concentration of the soil and detergent, e.g., for the sake of improved wash performance and/or turbidity sensing resolution.

Notably, the parameters of the additive mixing cycle and the agitation cycle may vary according to exemplary embodiments of the present subject matter. For example, the additive mixing cycle may have a mixing duration and the agitation cycle may have an agitation duration. According to example embodiments, the agitation duration may be at least 2 times, at least 5 times, at least 10 times, at least 20 times, or greater, than the mixing duration. For example, according to an example embodiment, the mixing duration may be between about 3 seconds and 2 minutes, between about 5 seconds and 1 minute, or about 15 seconds. In addition, according to example embodiments, the agitation cycle and the additive mixing cycle have different agitation profiles and/or agitation intensities.

As explained above, the first turbidity and the second turbidity may be used to determine the level of turbidity associated with wash additive versus the level of turbidity associated with soils that are extracted from the load of clothes being cleaned. This information may be used to improve subsequent performance of the wash cycle, e.g., by adjusting wash cycle parameters. Specifically, step260may include determining a wash cycle intensity based at least in part on the first turbidity and the second turbidity.

For example, step260may include determining a turbidity difference between the first turbidity and the second turbidity. This turbidity difference may generally represent the amount of soils extracted from the load of clothes. This turbidity difference may generally be quantified as a mathematical difference between the measured turbidities, as a ratio of the measured turbidities, or using any other suitable mathematical quantification or relationship. Accordingly, step260may further include selecting the wash cycle intensity based at least in part on this turbidity difference. In general, higher soil levels (e.g., associated with a higher turbidity difference) may result in a wash cycle intensity that has increased duration, a more intense agitation profile, and increased spin speed or agitation intensity, etc. By contrast, lower soil levels (e.g., associated with a lower turbidity difference) may result in a wash cycle intensity that has decreased duration, a milder agitation profile, and lower spin speeds or agitation intensities.

Step270may generally include completing a wash cycle at the determined wash cycle intensity (e.g., the wash cycle intensity determined at step260based on the turbidity difference). Notably, the performance of such a wash cycle may be more targeted to the precise type of clothes, the size of the load, the soil level of the load of clothes, etc.

As described generally above, method200includes adjusting a wash cycle intensity based on the measured turbidity during various points within an operating cycle. This process may be referred to generally herein as a smart wash cycle. It should be appreciated that method200may further include steps for ensuring that the wash cycle intensity is adjusted based on turbidity measurements only when the user desires to perform such a smart wash cycle. Accordingly, method200may further include determining that a user input comprises a smart wash cycle selection prior to operating the motor assembly to perform the additive mixing cycle. According to example embodiments, this user input may be obtained through control panel150, through external device192(e.g., such as a user's cell phone), or from any other suitable input source. According to still other embodiments, method200may include determining that the user has selected a standard wash cycle (e.g., not a smart wash cycle). According to such an embodiment, method200may further include performing a standard agitation/wash cycle. In this regard, the “standard agitation cycle” may refer to the factory default or programmed settings of washing machine appliance100during a standard operating cycle.

Referring now briefly toFIG.5, an exemplary flow diagram of a smart wash cycle300that may be implemented by washing machine appliance100will be described according to an exemplary embodiment of the present subject matter. According to exemplary embodiments, method300may be similar to or interchangeable with method200and may be implemented by controller156of washing machine appliance100. As shown, at step302, a user may configure the wash cycle, options, and operating parameters. For example, this may include a selection between a standard wash cycle or a smart wash cycle.

Step304may include starting an operating cycle of a washing machine appliance and step306may include performing a load sensing procedure, as will be understood to one having ordinary skill in the art. Step308may include filling the wash tub with wash fluid. For example, step308may include filling the wash tub with a target volume of wash fluid for performing the operating cycle.

Step310may include determining whether the smart wash cycle option was selected at step302. If the smart wash cycle was not selected or the standard wash cycle was selected, step312may include performing a normal agitation and wash cycle and continuing the wash cycle at step330. By contrast, if step310results in a determination that the smart wash cycle option was selected, step314may include performing a pre-sense agitate, e.g., such as the additive mixing cycle. As explained above, this additive mixing cycle is intended to distribute or disperse wash additive without extracting a significant amount of soil from the load of clothes. Step316may include obtaining a first turbidity measurement using a turbidity sensor.

Step318may include performing a wash cycle load of clothes, e.g., by soaking the load of clothes, agitating the load of clothes, etc. Step320includes obtaining a second turbidity reading using the turbidity sensor. Step322includes determining a turbidity difference between the second turbidity (e.g., measured at step320) and the first turbidity (e.g., measured at step316). Step324may include determining wash cycle parameters based on the turbidity difference. For example, the turbidity difference may be compared to a predetermined turbidity difference to determine whether the wash cycle intensity should be increased or decreased. According to still other embodiments, step324may include using a lookup table or algorithm that relates a specific turbidity difference to a specific set of wash cycle parameters.

Specifically, if step324results in a determination that the turbidity difference is large (e.g., above a predetermined threshold), step326may include performing a wash cycle with a normal or increased duration and/or intensity. By contrast, if step324results in a determination that the turbidity difference is small (e.g., below the predetermined threshold), step328may include performing a wash cycle with a reduced agitation intensity or duration. The wash cycle may continue step330.

FIGS.4and5depict steps performed in a particular order for purposes of illustration and discussion. Those of ordinary skill in the art, using the disclosures provided herein, will understand that the steps of any of the methods discussed herein can be adapted, rearranged, expanded, omitted, or modified in various ways without deviating from the scope of the present disclosure. Moreover, although aspects of method200and method300are explained using washing machine appliance100as an example, it should be appreciated that this method may be applied to the operation of any suitable laundry appliance, such as another washing machine appliance.

As explained above, aspects of the present subject matter are directed to a washing machine appliance that includes a turbidity sensor located in the bottom of the wash tub in contact with the wash fluid. The turbidity sensor may be used to distinguish soil level of wash fluid in the wash tub from detergent or other additives, and the washing machine may use this information to adjust various washing parameters based on the detected soil level and user inputs. The turbidity sensor may be positioned in the bottom of the wash tub in contact with the wash fluid. Prior to the start of the sensing phase, the user may provide an input to activate a smart wash algorithm (e.g., via a button on the user interface, using a voice command, via selection through a companion mobile application, etc.). After load sensing, filling, and dispensing procedures have been performed, the washing machine may perform an initial, short agitation to dissolve detergent and other additives (e.g., not agitation intended to clean clothes). After this short agitation, the washing machine may sample the turbidity of the wash fluid to establish a baseline reading (turbidity index 1). This turbidity reading may be primarily a function of detergent and other wash additives—i.e., the influence of soil level on this turbidity reading is minimal. Additional agitation and soaking of the clothes may then be performed and a second turbidity reading may be taken (turbidity index 2). This second turbidity reading may be a function of both detergent and extracted soil. A turbidity difference (delta) may be calculated between the second and first turbidity readings, effectively subtracting out the influence of detergent, such that this turbidity delta is a function of extracted soil. The remaining agitation time or other wash parameters may be adjusted based on user selections (such as cycle selected, soil level, power/care, tangle control, etc.) and the calculated turbidity delta. For example, a larger turbidity delta may result in longer agitate times as compared to a smaller turbidity delta.