Estimating ambient temperature related to environment around air moving device

Abstract

A method of estimating an ambient temperature associated with an environment around an air moving device is described. The method comprises: determining, using a sensor configured to measure a temperature of a thermal environment of the device: a first value of the temperature of the thermal environment at a turn-off time of a motor of the device; and a second value of the temperature at the end of the time interval starting from the start time. The start time is a time at which the temperature has decreased to a first value after an initial increase after the shutdown time. The method includes estimating an ambient temperature based on the first and second values, the time interval, and a predetermined cooling characteristic of the thermal environment. A set of machine-readable instructions for performing the method and an air moving device comprising a processor and a memory comprising such instructions are also described.

Description

Background Art

[0001] An air moving device, such as a vacuum cleaner, may employ one or more control methods. Example control methods may improve the user experience by automatically optimizing the balance between battery runtime and suction power. For robust, consistent, and reliable operation of such control methods, external, environmental, and operational factors may be considered. One such factor is ambient temperature, i.e., the temperature of the environment surrounding the air moving device. For example, ambient temperature may affect the speed of the air moving device's motor when the motor is driven at a given power, as well as the pressure generated within the device during operation. Summary of the Invention

[0002] According to a first aspect of the invention, there is provided a method of estimating an ambient temperature associated with an environment surrounding an air moving device, the method comprising: determining, using a temperature sensor configured to measure the temperature of a thermal environment of the air moving device, a first value of the temperature of the thermal environment at an off-time of a motor of the device; and a second value of the temperature of the thermal environment at a second time, wherein the second time is at the end of a time interval starting at a start time, and wherein the start time is a time after the off-time at which the temperature of the thermal environment has dropped to the first value after a temperature increase; and performing a determination process to determine an estimate of the ambient temperature based on the first value, the second value, the time interval, and a predetermined cooling characteristic of the thermal environment.

[0003] When the motor of an air moving device is in operation, heat may be generated due to, for example, friction from air flowing through the device, mechanical movement of the motor, and resistive heating from electrical components of the device. Once the motor is turned off, these heating sources may be removed or reduced, and the device may begin to cool toward the temperature of the surrounding environment of the air moving device, which may be referred to as the ambient temperature.

[0004] This method can allow for estimating the ambient temperature based on measurements taken by a temperature sensor configured to measure the temperature of the device's thermal environment, which may differ from the ambient temperature. This can, for example, allow a temperature sensor used to monitor temperatures for other control aspects of the device (e.g., the temperature associated with the device's motor) to be used to estimate the ambient temperature when the device's motor is activated or when the motor is not operating. Thus, this method can allow for estimating the ambient temperature without the use of additional temperature sensors. This can provide cost and weight savings and, for example, reduce the complexity involved in assembling the device.

[0005] This method can allow for a robust and accurate estimate of the ambient temperature. For example, by determining the start time as the time when the temperature of the thermal environment returns to a first value, the estimate of the ambient temperature can account for the effects of thermal soak of the thermal environment, which may result in an initial increase in the temperature of the thermal environment after the device is shut down. Consequently, the estimate of the ambient temperature can be more accurate and robust in the event of such thermal soak.

[0006] The predetermined cooling characteristic may be a predetermined cooling time constant of the thermal environment.

[0007] This can allow an estimate of the ambient temperature to be determined based on the observed cooling rate of the thermal environment and based on a predetermined cooling constant that characterizes the thermal environment. The cooling constant can be determined, for example, by measuring the cooling rate of the thermal environment under known conditions. Alternatively, the cooling constant can be determined by simulating the cooling of the thermal environment. As another alternative, the cooling constant can be determined analytically, for example, by using an analytical expression that includes values ​​for one or more parameters that characterize the thermal behavior of the thermal environment (e.g., specific heat capacity, mass, heat transfer coefficient, and heat transfer surface area).

[0008] The determining process may include determining the estimate of the ambient temperature by performing a cooling curve calculation using the first value, the second value, the time interval, and a predetermined cooling constant to determine the estimate of the ambient temperature.

[0009] This may allow the ambient temperature to be estimated based on an expression relating the observed cooling rate of the thermal environment to the ambient temperature.

[0010] The cooling curve calculation may include determining an estimate of the ambient temperature based on an expression representing exponential cooling of the thermal environment.

[0011] This can allow an estimate of the ambient temperature to be determined by using an expression based on the cooling curve of the thermal environment, which cooling curve represents an exponential decay of the temperature of the thermal environment towards the ambient temperature. By using a predetermined cooling constant, this exponential relationship can be used to relate the observed cooling rate to the ambient temperature towards which the temperature of the thermal environment decreases.

[0012] Cooling curve calculations can take the following forms:

[0013]

[0014] in, is an estimate of the ambient temperature, is the second value of the temperature of the thermal environment, is the first value of the temperature of the thermal environment, is the time interval between the start time and the second time, and is the predetermined cooling constant of the thermal environment.

[0015] This equation may allow an estimate of the ambient temperature to be calculated based on an observed rate of cooling of the thermal environment from a first value to a second value and a predetermined cooling constant for the thermal environment.

[0016] The second time may be the time when the motor of the air moving device is turned on for the first time after the off time.

[0017] By determining the ambient temperature at a second time when the motor is turned on after being off for a period of time, an updated estimate of the ambient temperature can be provided when the motor is turned back on. When the air moving device is turned back on after the off time, the temperature of the thermal environment of the device may remain above the ambient temperature because sufficient time may not have passed since the off time to allow the thermal environment to cool to the ambient temperature. This method can provide an estimate of the ambient temperature that can be used as an input to a control system configured to control various aspects of the operation of the device, such as the power supply to the drive motor.

[0018] The method may include monitoring the temperature of the thermal environment using a temperature sensor after the off time; and determining the start time as a time when the temperature of the thermal environment decreases to a first value after the temperature increases after the off time based on the monitoring.

[0019] The time at which the temperature of the thermal environment returns to the first value after the temperature increase after the off time can be determined by monitoring the temperature of the thermal environment using a temperature sensor. This can provide an accurately determined start time to form an input to the determination process, and thus can allow the determination process to provide an accurate and robust estimate of the ambient temperature.

[0020] The temperature sensor may be configured to measure a temperature associated with the motor of the air moving device while the motor is operating.

[0021] Thus, the temperature sensor may provide dual functionality: measuring the temperature of components of the motor assembly and / or air flowing through the motor when the motor is operating, and allowing an estimate of the ambient temperature to be determined at motor startup or during periods when the motor is off.

[0022] The thermal environment may include an enclosure inside an air moving device containing a temperature sensor.

[0023] Thus, an estimate of the ambient temperature may be determined based on temperature measurements from the housing inside the device.In addition to providing input for determining an estimate of the ambient temperature, these temperature measurements may also be used to monitor and / or control various aspects of the operation of the device.

[0024] The housing may be the casing of a motor of the air moving device.

[0025] For example, the temperature sensor may be located inside the housing of the motor, for example, and configured to measure the temperature of certain components of the motor or the temperature of air flowing through the motor while the motor is operating.

[0026] According to a second aspect of the present invention, there is provided a set of machine readable instructions which, when executed by one or more processors, cause the performance of the method according to the first aspect of the present invention.

[0027] According to a third aspect of the invention, there is provided an air moving device comprising: a temperature sensor configured to measure the temperature of a thermal environment of the air moving device; a processor; and a memory comprising a set of machine-readable instructions that, when executed by the processor, cause the processor to perform a method according to the first aspect of the invention.

[0028] The air moving device may be a vacuum cleaner. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic diagram illustrating a perspective view of an example air moving device.

[0030] Figure 2 It shows Figure 1 Schematic diagram of a highly simplified cross-sectional representation of the motor assembly of an air moving device.

[0031] Figure 3 is a graph illustrating a first example temperature distribution of the thermal environment of an air moving device.

[0032] Figure 4 is a graph illustrating a second example temperature distribution of the thermal environment of an air moving device.

[0033] Figure 5 is a flow chart illustrating a first example method of estimating the ambient temperature of an air moving device.

[0034] Figure 6 is a flow chart illustrating a second example method of estimating the ambient temperature of an air moving device.

[0035] Figure 7 is a schematic diagram illustrating aspects of an example usage scenario for an air moving device. DETAILED DESCRIPTION

[0036] Figure 1An air-moving device 100 is shown. In this example, the air-moving device 100 is a vacuum cleaner. The vacuum cleaner 100 includes an inlet tube 102, with a tool 104 attached to the distal end of the inlet tube 102. The tool 104 is used to engage a surface to be cleaned by the vacuum cleaner 100 and includes an air inlet (not shown) for the vacuum cleaner 100. The tool 104 can be active, including one or more mechanically operated components, such as a rotating brush bar, to assist in the cleaning task. Alternatively, the tool 104 can be passive and not include any such mechanically operated components. However, a passive tool may include elements such as bristles to assist in the cleaning task. In some examples, the inlet tube 102 or a portion thereof may be removable. In such examples, when the inlet tube 102 or a portion thereof is removed, the tool, such as a passive tool, can be attached to the vacuum cleaner 100. The vacuum cleaner 100 also includes a dirt separation chamber 106, which may be, for example, a cyclone chamber. The vacuum cleaner 100 includes an outer housing 120 containing a motor assembly 200 (see Figure 2 ).

[0037] The vacuum cleaner 100 also includes a processor 108 and a memory 110 for storing machine-readable instructions that are executed by the processor 108 to control the operation of the components of the vacuum cleaner 100. In an example, the machine-readable instructions, when executed, may cause the processor 108 to perform any of the example methods described herein or aspects of such methods.

[0038] Figure 2 An example schematic diagram of the motor assembly 200 of the vacuum cleaner 100 is shown. Figure 1 As mentioned in the description of FIG, in use, the motor assembly 200 is housed within the housing 120 of the device 100. For clarity, Figure 2 The outer housing 120 is omitted. The motor assembly 200 includes a set of coils 202, a shaft 204 on which magnets (not shown) are mounted, bearings 206, and an impeller 208. The motor assembly 200 includes a motor air inlet 210 and an air outlet / diffuser 212. The motor assembly includes a circuit board 214 on which sensors including a temperature sensor 216 and a pressure sensor 218 are mounted. The motor assembly 200 includes a motor housing 224, in which the other components are housed. The motor assembly 200 also includes a pre-motor filter 226 for filtering air drawn into the motor during use.

[0039] refer to Figure 1 and Figure 2In use, the motor of the motor assembly 200 draws air through the air intake of the device 100 and along the air flow path 128, which flows through the device 100 and exits the device through the exhaust port 112. After being drawn into the device 100 through an air inlet (not shown) in the tool 104, the air flow path 128 continues through the inlet duct 102, then through the dirt separation chamber 106, then through the motor assembly 200, and finally exits the device 100 through the exhaust port 112.

[0040] Return to Figure 2 When the motor is used in the device 100, current is passed through the coil 202 in a manner that causes a changing magnetic field to be generated. This changing magnetic field acts on the magnets 206 on the shaft 204 to rotate the shaft 204 about its longitudinal axis. This in turn rotates the impeller 208. Air driven by the impeller 208 is drawn into the air moving device 100 along the air flow path 128. The air flow path 128 enters the motor assembly 200, passes through the pre-motor filter 226, which removes particulate matter from the air, and is discharged through the air inlet 210 (at Figure 2 The airflow path 128 continues through the motor to the impeller 208 and, after passing through the impeller 208, exits the motor assembly 200 through the air outlet 212 and then exits the device 100 through the exhaust port 112.

[0041] Device 100 can be configured to implement one or more control methods, for example, by processor 108 executing machine-readable instructions stored on storage device 110. Such control methods can be used to control or monitor certain aspects of the operation of device 100. For example, a control method can be implemented to control the power provided to a motor driving device 100. As another example, a control method can be implemented to monitor device 100 to detect certain conditions, such as when a filter of device 100 should be cleaned or replaced. In some examples, based on such monitoring, the control method can include providing an alert to a user of device 100.

[0042] Various parameters of the device 100 can be monitored, for example, to be used as input to one or more control methods, such as those examples described above. The parameters that can be monitored can, for example, include the rotational speed of the motor of the device 100, the operating pressure within the motor assembly 200 (e.g., when the motor is operating or when the motor is not operating), and the operating temperature within the motor assembly 200 (e.g., when the motor is operating or when the motor is not operating). Various sensors can be used to measure such parameters. For example, a motor speed sensor (not shown) can be configured to measure the rotational speed of the motor. The temperature sensor 216 and the pressure sensor 218 can be used to measure the temperature and pressure within the motor assembly 200, respectively.

[0043] One particular parameter that may be monitored is the ambient temperature, i.e., the temperature of the environment surrounding the device 100. The value of the ambient temperature in which the device 100 operates may, for example, be used as an input to a corresponding control method for controlling the power supplied to the motor and for determining when the filter of the device 100 should be cleaned or replaced.

[0044] exist Figure 1 and Figure 2 In an example air moving device of , an estimate of the ambient temperature may be determined based on a temperature value measured by a temperature sensor 216 of the thermal environment of the device 100. The thermal environment includes the temperature sensor 216 and the immediate surroundings of the temperature sensor 216, which, for the purposes of modeling the thermal behavior of the device 100, may be treated as forming a thermal system that is arranged such that it can exchange heat with the surroundings. As discussed above, the temperature sensor 216 is internal to the motor assembly 200, which, in use, is enclosed within the outer housing 120 of the device 100. Thus, in this example, the thermal environment includes the temperature sensor 216 itself, and may include other components of the device 100 that are in direct or indirect thermal contact with the temperature sensor 216. For example, the thermal environment may include the circuit board 214 on which the temperature sensor 216 is mounted and the air surrounding the temperature sensor 216.

[0045] Figure 3 Included is a graph showing a simplified schematic representation of a first example temperature distribution of the thermal environment of device 100. In summary, Figure 3 The temperature profile of the thermal environment of the device 100 is shown over a period of time, starting with the motor of the device 100 being in operation, wherein the motor is turned off, and then turned back on again after a cooling period. For example, the temperature profile may correspond to a scenario in which a user initially uses the vacuum cleaner 100 to clean a surface, stops cleaning the surface for a period of time by switching the motor off, and then turns the motor back on to resume cleaning after a period of time.

[0046] exist Figure 3 in, at some time Previously, the motor of the device 100 was in operation. During the period during which the motor was in operation, the thermal environment was heated due to the operation of the motor. For example, the thermal environment may be heated due to friction from the movement of the motor and / or due to resistive losses from components configured to drive the motor. Therefore, the temperature value measured by the temperature sensor 216 when the motor was in operation was greater than the ambient temperature. .exist Figure 3 In the simplified temperature curve, The temperature during the previous period was constant In some examples, the temperature during this period can remain substantially constant while the motor is operating because, although heat is generated by the operation of the motor, the airflow through the motor carries away heat such that a substantially steady state can be maintained. Figure 3 In the example shown in the figure, the temperature may reach The steady state at has previously increased from a lower value. However, it should be noted that in other examples, immediately after The temperature may not be constant during the previous period. For example, when Even when the motor is turned off, the temperature may still increase.

[0047] exist When , the motor of the device 100 is turned off. When the temperature of the thermal environment measured by the temperature sensor 216 is With the motor of the device 100 turned off, the heating source that was present when the motor was operating is removed. Initially, as heat is lost from the hot environment to the surrounding environment, the temperature of the hot environment moves towards the surrounding temperature. After the motor is turned off, the temperature of the thermal environment can be modeled as the ambient temperature is an exponential decay of the asymptote.

[0048] The thermal environment moves towards the ambient temperature within the time interval Δt Continue cooling. Time interval Δt at time End, in time The motor is switched back on and heating of the thermal environment begins again. Figure 3 The dashed line in the figure shows the expected temperature of the thermal environment if the motor is not restarted at t1, which indicates the direction Continuous exponential decay.

[0049] The temperature of the thermal environment during the time interval Δt can be expressed as:

[0050]

[0051] in At a certain time The temperature at which ; It is a hot environment The temperature at that time; and is the cooling constant of the thermal environment.

[0052] Equation 1 can be rearranged to provide the ambient temperature The following expression:

[0053]

[0054] Figure 4 is a graph showing a simplified schematic representation of a second example temperature distribution of the thermal environment of device 100. This model takes into account the effect that may occur in certain examples where the temperature measured by temperature sensor 216 increases after the off time. For example, this effect may occur at high motor power levels that generate a lot of heat. In this case, when the motor is operating, the heat can be effectively removed from the thermal environment by the higher airflow generated by the high motor power. Therefore, as in Figure 3 In the example, at this time The temperature of the motor while it is in operation may remain substantially constant at T0, although in this example T0 may be higher due to increased heating from the higher motor power. Figure 3 In other examples, such as the one above about Figure 3 As discussed, the temperature immediately before shutting down may not be constant. For example, the temperature may still increase during the shut-down time because the thermal environment has not yet reached a steady-state temperature. Figure 3 In the example, the motor is At this time, the heating of the thermal environment by the operation of the motor stops. At the same time, the airflow generated by the operation of the motor stops, so that heat is no longer effectively removed from the motor assembly 200. Figure 4 In the example shown, this results in heat soaking of the temperature sensor 216, which may occur, for example, via heat conduction from the circuit board 214 into the temperature sensor 216. Figure 4 As shown, the temperature of the thermal environment increases over a period of time after the motor is shut down.

[0055] During closing time After a short period of time, the heat soak effect begins to weaken, making the After a certain time, the temperature of the thermal environment reaches the highest temperature. Then the temperature begins to decrease. , the temperature of the thermal environment has returned to the temperature at the time of shutdown In time The time between motor restart The time interval Δt between Figure 3 The same expression (Equation 1) is formulated to represent the temperature of the thermal environment, since the thermal environment is toward the ambient temperature Cooling exponentially. Figure 3 In the example, the hot environment continues to cool until the motor is turned back on. , at which point the temperature of the thermal environment begins to increase again.

[0056] Figure 5is a flow chart illustrating an example method 500 for estimating an ambient temperature associated with the environment surrounding an air moving device 100. As an example, referring to Figure 4 , the method 500 may allow for determining the ambient temperature based on the temperature measurement measured by the temperature sensor 216 Estimates.

[0057] Method 500 includes, at block 502 , determining, using temperature sensor 216 configured to measure a temperature of a thermal environment of air moving device 100 , a first value of the temperature of the thermal environment at an off time of a motor of device 100 .

[0058] As an example, refer to Figure 4 , block 502 may include measuring the shutdown time of the motor of the device 100 using the temperature sensor 216 The temperature of the thermal environment .

[0059] At block 504, method 500 includes determining a second value for the temperature of the thermal environment at a second time using temperature sensor 216. The second time is at the end of the time interval that begins at the start time, and the start time is a time after the off time when the temperature of the thermal environment has decreased to the first value after the temperature increased.

[0060] As an example, refer to Figure 4 , can return to the off time by measuring the temperature of the thermal environment using the temperature sensor 216 The temperature after The start time is determined by the time of Figure 4 In Chinese For example, the temperature of the thermal environment measured by the temperature sensor 216 can be continuously monitored, for example at a specific frequency (such as 1 Hz). The time when the motor is turned off can be recorded. . Can be closed during The temperature measured by the temperature sensor 216 is then monitored and can be recorded After that the temperature returns to the shutdown temperature Time and set it as the start time. Then, block 504 may include measuring the temperature of the thermal environment using the temperature sensor 216 at a second time after the start time. The second time may be the time when the motor is turned back on. Any time before.

[0061] At block 506 , the method 500 includes performing a determination process to determine an estimate of the ambient temperature based on the first value, the second value, the time interval, and a predetermined cooling characteristic of the thermal environment.

[0062] As an example, refer to Figure 4, block 506 may include applying the expression set forth above for ambient temperature to determine an estimate of the ambient temperature. That is, Equation 2 above may be used to determine the ambient temperature Estimates.

[0063] In Equation 2 and can be measured by the temperature sensor 216, as described above, where is the time interval that has elapsed since the start time at which the estimation of the ambient temperature is made.

[0064] Cooling constant of thermal environment Determined in advance by a suitable method. For example, when cooling under conditions where the ambient temperature is known, the cooling constant can be measured by measuring the temperature distribution of the thermal environment. The cooling constant can then be determined by fitting the curve to the temperature curve , for example, assuming an exponential decay curve according to the above expression.

[0065] Alternatively, the cooling constant can be determined analytically For example, the cooling constant It can be determined according to the following expression:

[0066]

[0067] in is the specific heat capacity of the thermal environment in J / (K*kg), is the mass of the thermal environment in kg, W / (m 2 *K) is the heat transfer coefficient of the thermal environment, and It is m 2 It is the heat transfer surface area between the unit thermal environment and the surrounding environment.

[0068] As referenced above Figure 3 and Figure 4 As stated, is the temperature sensor 216 at a certain time in the time interval Δt The measured temperature of the thermal environment as it cools towards the ambient temperature during the time interval Δt.

[0069] In one specific example, It's this temperature , the temperature is at the closing time The temperature of the thermal environment when the motor of the device 100 is then turned back on. This can provide An estimate of the ambient temperature of the motor may be used, for example, in a method for controlling the power supplied to the motor and / or in one or more methods for monitoring the operation of the device 100 when the motor is running.

[0070] Additionally or alternatively, the time interval ∆t before the motor is turned back on can be estimated at any given time by entering the measured value T(t) at the given time t into the above expression For example, the ambient temperature may be estimated at a given predetermined interval after the start time instead of, or in addition to, estimating the ambient temperature at the time the motor is turned on. For example, the ambient temperature may be estimated after a cooling constant τ has elapsed after the start time. According to the following expression, the temperature of the thermal environment after a cooling constant can be estimated to have dropped by and 63.2% of the difference between the two.

[0071]

[0072] By measuring the temperature of the thermal environment at a constant cooling time after the start time, the ambient temperature can be determined using Equation 4 In this way, the estimate can be determined in a computationally economical manner because none of the terms in the expression include the calculation of an exponential function.

[0073] When an estimate of the ambient temperature is to be made, the temperature of the thermal environment may remain higher than the ambient temperature, for example, due to the heat capacity of the temperature sensor 216 itself, the circuit board 214, and the surrounding housing. For example, if such a temperature measurement is directly used as an estimate of the ambient temperature, this will provide an incorrect estimate. Inputting such an incorrect estimate into the control method may, for example, lead to degradation of the operation of the control method. The example methods described herein can allow for providing an accurate estimate of the ambient temperature while taking into account factors such as those described above.

[0074] By estimating the ambient temperature using values ​​determined by temperature sensors in the thermal environment of the device, an estimate of the ambient temperature can be obtained without the need for additional temperature sensors. This can provide cost and weight savings as well as reduce the complexity of assembling the device 100. As an example, the temperature sensor 216 in the exemplary device 100 can be used to obtain an estimate of the ambient temperature when the motor is not operating (e.g., at motor startup), while also providing temperature measurements that may be relevant to the operation of the motor when the motor is operating. For example, the temperature sensor 216 can be used to monitor the temperature of components of the motor or the temperature of the air flowing into the motor while the motor is operating. Such measurements can, for example, be used to detect potential overheating in the motor assembly 200.

[0075] Furthermore, method 500 can allow for an accurate and robust estimate of the ambient temperature even in situations where the temperature of the thermal environment increases after the motor's shutdown time, for example, due to the aforementioned type of heat soak. By performing a cooldown calculation in which the starting point for modeling exponential cooling of the thermal environment is set to the time at which the temperature has returned to the shutdown temperature, the effects of heat soak are accounted for in the calculation of the ambient temperature. For example, if the cooldown calculation were instead performed assuming that the thermal environment cools exponentially from the shutdown time, an incorrect result for the ambient temperature could be obtained in the event of the aforementioned type of heat soak.

[0076] Figure 6 is a flow chart illustrating another example method 600 of determining an estimate of an ambient temperature associated with the environment of air moving device 100 .

[0077] Method 600 includes, at block 602, determining a first value for a temperature of a thermal environment of air moving device 100 at an off time of a motor of device 100. Block 602 may include any of the features described above with reference to block 502.

[0078] As an example, refer to Figure 3 or Figure 4 , block 602 may include measuring the shutdown time of the motor of the device 100 using the temperature sensor 216 The temperature of the thermal environment .

[0079] At block 604 , method 600 includes determining a second value for the temperature of the thermal environment at a second time at the end of a time interval beginning at the start time, the start time being at or later than the shut-off time.

[0080] At block 606, method 600 includes selecting a determination process from a plurality of determination processes for determining an estimate of the ambient temperature at a second time. The selection is based on one or more predetermined criteria related to the first value and the second value and / or the time interval. The plurality of determination processes includes a first determination process that includes determining an estimate of the ambient temperature at the second time based on the first value, the second value, the time interval, and a predetermined cooling characteristic of the thermal environment.

[0081] At block 608 , the method 600 includes executing the selected determination process to determine an estimate of the ambient temperature.

[0082] The first determination process may have the above reference Figure 5 As an example, refer to Figure 3 and Figure 4 , the first determination process may include determining an estimate of the ambient temperature based on Equation 2 in the manner described above.

[0083] The first determination process may include setting a start time. For example, if the temperature of the thermal environment is determined to be within the off time Then it rises, as Figure 4 In the example shown, the start time can be set to when the temperature has returned to the shutoff temperature. Time That is, it can be assumed that the temperature of the thermal environment is The cooling curve calculation is performed starting with an exponential decrease, as in the example method 500 .

[0084] Alternatively, if the temperature of the thermal environment is determined at the closing time Then it drops, as in Figure 3 In the example shown in FIG, the closing time may be set at block 504. That is, it can be assumed that the temperature of the thermal environment changes from the closing time Starts an exponential decrease to perform the cooling curve calculation.

[0085] The one or more predetermined criteria on which selection of the determination process is based may include a first predetermined criterion that the magnitude of the decrease in temperature from the first value to the second value is greater than or equal to a predetermined amount.

[0086] For example, in Figure 3 and Figure 4 In the example, to determine the ambient temperature To meet the first predetermined criterion, a temperature shift from the shutdown temperature must have occurred. For example, if you want to Estimating the ambient temperature, the temperature drop over the time interval Δt is The temperature drop must be greater than a predetermined minimum temperature drop. For example, the predetermined minimum temperature drop can be a temperature value In one example, the predetermined minimum temperature drop may be a value in degrees Celsius. For example, if is 50°C, the minimum temperature drop may be about 5°C.

[0087] The one or more predetermined criteria on which the selection of the determination process is based may include a second predetermined criterion that the time interval is less than a predetermined time interval. The predetermined time interval may be a time interval during which the temperature of the thermal environment is expected to substantially decrease to the ambient temperature. For example, if the time elapsed from the start time when the ambient temperature is to be estimated is such that the temperature of the thermal environment is expected to remain above the ambient temperature, the second predetermined criterion may be satisfied. The predetermined time interval may be based on a cooling constant For example, the predetermined time interval can be equal to the cooling constant As an example, the cooling constant It may be on the order of tens of seconds to several minutes, for example, from about 30 seconds to about 5 minutes.

[0088] The predetermined minimum temperature drop can be determined in the cooling constant For example, the cooling constant A larger value of will mean that the cooling constant A given minimum temperature drop will take longer to occur than with a smaller value of . The time it takes for a minimum temperature drop to occur may also depend on the thermal environment The ambient temperature towards which cooling is directed. For example, due to the exponential nature of temperature decay, the shut-off temperature and ambient temperature A larger difference between will cause a given minimum temperature drop to occur more quickly. Due to the exponential nature of temperature decay, the rate of temperature drop will be greatest at the start of cooling. Therefore, the minimum temperature drop can occur relatively quickly. For example, depending on the difference between the shutdown temperature and the ambient temperature, the minimum temperature drop can occur at a time that is proportional to the cooling constant. occurs over a relatively short timeframe. Purely as an example, when the cooling constant On the order of minutes, the minimum temperature drop may take on the order of tens of seconds to occur.

[0089] In one example, if the first predetermined criterion and the second predetermined criterion are met, the first determination process is selected. Figure 3 and Figure 4 If the Estimated ambient temperature When the minimum temperature drop occurs first, and secondly the time interval Δt is less than the predetermined time interval, the first determination process can be applied to estimate the ambient temperature As described above, the first determination process may include performing a cooling curve calculation based on Equation 2.

[0090] By applying the cooling calculation of Equation 2 under the condition that a minimum temperature drop has occurred, the reliability of the results of the cooling calculation can be improved.

[0091] By applying the cooling calculation of Equation 2, further, under the condition that the time interval is less than the predetermined time interval, when there is insufficient time for the thermal environment to decay to substantially the ambient temperature , the cooling curve calculation can be applied.

[0092] On the other hand, if the elapsed time is greater than the predetermined time interval, the second determination process may be selected. For example, since the predetermined time interval may be a time interval in which the temperature of the thermal environment can be expected to have cooled to the ambient temperature, such as a cooling constant If the predetermined time interval has elapsed, the value measured by the temperature sensor 216 may be used directly as an estimate of the ambient temperature.

[0093] If the first predetermined criterion is not met and the second predetermined criterion is met, a third determination process may be selected. For example, if the minimum temperature drop has not occurred and the time interval is less than a predetermined time interval, the third determination process may be selected. In an example, the third determination process may include determining an estimate of the ambient temperature based on an estimate of the ambient temperature obtained at an earlier time. This may allow the use of a previous estimate of the ambient temperature to estimate the ambient temperature when the minimum temperature drop required for applying the cooling curve calculation has not occurred and the time elapsed since the start time is insufficient for the temperature of the thermal environment to cool to the ambient temperature.

[0094] Figure 7 is a schematic diagram illustrating aspects of the operation of the apparatus 100 when executing an example of the method 600 to estimate the ambient temperature. That is, Figure 7 Representing a usage scenario of device 100, as time increases horizontally from left to right, periods of time when the motor of device 100 is operating (denoted as "on") and periods of time when the motor of device 100 is not operating (denoted as "off") are shown. In this example, an estimate of the ambient temperature is obtained each time the motor of device 100 is turned on.

[0095] Figure 7 Shows a predetermined time interval , which predetermined time interval is used as part of the process of selecting which determination process will be used to estimate the ambient temperature. In this example, is the time interval for the thermal environment to cool from the shutdown temperature to the ambient temperature. As in the example described above, for example, It can be about five times the cooling constant of the hot environment.

[0096] It should be noted that in Figure 7 For simplicity, we consider an example where the temperature distribution of the thermal environment when closed follows a formula such as Figure 3 The distribution shown makes the start time always equal to the close time However, regarding Figure 7 The principle described also applies to Figure 4 Example shown where the temperature of the thermal environment increases after the off time and the start time is set to a time later than the off time .

[0097] exist Figure 7 In time Before, the motor of the device 100 is turned off. , the motor is turned on. Figure 7 Shown in time , the motor has been switched off for longer than the predetermined time interval Therefore, it can be expected that The temperature measured by the temperature sensor 216 is substantially equal to the ambient temperature Therefore, by directly using The value measured by the temperature sensor 216 is obtained as an estimate of the ambient temperature. Estimation of ambient temperature.

[0098] In time , the motor is turned off again. The motor remains off until , the motor is turned on again. as in In the case of Therefore, the time is also determined by directly using the measured temperature value as an estimate of the surrounding temperature An estimate of the ambient temperature at the location.

[0099] At time t D , and turn off the motor again. The motor remains off until time t E , at time t E Restart again. Time t E and t D The time interval between In addition, the time interval t D to t E is short enough so that the minimum temperature drop for applying the cooling curve calculation using Equation 2 has not yet occurred. Thus, to estimate t E The ambient temperature at time t is used, using the previous estimate of the ambient temperature. In this example, the most recent estimate of the ambient temperature is used, which in this case is at time t C An estimate of the ambient temperature obtained at .

[0100] At time t F , the motor turns off again. The motor remains off until time t G Time interval t F to t G Less than the predetermined time interval In addition, the time interval t F to t Glong enough for the minimum temperature drop to occur. Therefore, to estimate the time t G At the ambient temperature, the cooling curve calculation according to Equation 2 is performed.

[0101] Through the above-described method, the determination process can be selected in a manner that allows accurate and efficient calculation of the ambient temperature in a range of situations. For example, during periods when the motor has been off for extended periods, directly using the value measured by the temperature sensor can provide an efficient and accurate means of estimating the ambient temperature. During periods when the value measured by the temperature sensor can be expected to be greater than the ambient temperature, if a minimum temperature drop has not yet occurred, a previous estimate of the ambient temperature can be used, which can provide a quick and efficient estimate of the ambient temperature. Alternatively, if a minimum temperature drop has already occurred, a cooling curve calculation can be performed, allowing a reliable and up-to-date estimate of the ambient temperature to be calculated.

[0102] Although in the above examples, the method for determining an estimate of ambient temperature is performed by an air moving device, in other examples, at least some aspects of the method can be performed by another device. For example, the air moving device can communicate with another device (such as a cloud computing device or a smartphone), which can be provided with temperature measurements obtained by the device's temperature sensor and can perform certain aspects of the method for determining an estimate of ambient temperature based on the provided temperature measurements.

[0103] The above embodiments should be understood as illustrative examples of the present invention. Other embodiments are contemplated. It should be understood that any feature described with respect to any one embodiment may be used alone or in combination with other described features, and may also be used in combination with one or more features of any other embodiment, or in combination with any combination of any other embodiments. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the present invention as defined in the appended claims.

Claims

1. A method of estimating an ambient temperature associated with an environment surrounding an air moving device, the method comprising: Determine using a temperature sensor configured to measure the temperature of the thermal environment of the air moving device: a first value of the temperature of the thermal environment at an off-time of a motor of the device; and a second value of the temperature of the thermal environment at a second time, wherein the second time is at the end of a time interval beginning at a start time, and wherein the start time is a time after the off time when the temperature of the thermal environment has decreased to the first value after the temperature increase; and A determination process is performed to determine an estimate of the ambient temperature based on the first value, the second value, the time interval, and a predetermined cooling characteristic of the thermal environment.

2. The method according to claim 1, wherein The predetermined cooling characteristic is a predetermined cooling time constant of the thermal environment.

3. The method according to claim 2, wherein: The determining process includes determining an estimate of the ambient temperature by: A cooling curve calculation is performed using the first value, the second value, the time interval, and the predetermined cooling constant to determine an estimate of the ambient temperature.

4. The method according to claim 3, wherein: The cooling curve calculation includes determining an estimate of the ambient temperature based on an expression representing exponential cooling of the thermal environment.

5. The method according to claim 4, wherein the cooling curve calculation adopts the following form: ， Its T ambient is an estimate of the ambient temperature, T(t) is a second value of the temperature of the thermal environment, T0 is a first value of the temperature of the thermal environment, t is a time interval between the start time and the second time, and τ is a predetermined cooling constant of the thermal environment.

6. The method of any preceding claim, wherein the second time is the time at which the motor of the air moving device is first turned on after the off time.

7. A method according to any preceding claim, comprising: After the off time, monitoring the temperature of the thermal environment using the temperature sensor; and Based on the monitoring, the start time is determined as a time when the temperature of the thermal environment decreases to the first value after the temperature increase after the shut-off time.

8. The method of any preceding claim, wherein the temperature sensor is configured to measure a temperature associated with a motor of the air moving device when the motor is operating.

9. The method of any preceding claim, wherein the thermal environment comprises an enclosure inside the air moving device, the enclosure containing the temperature sensor.

10. The method of claim 9, wherein the housing is a casing of a motor of the air moving device.

11. A set of machine readable instructions which, when executed by one or more processors, cause the method of any one of claims 1 to 10 to be performed.

12. An air moving device comprising: a temperature sensor configured to measure a temperature of a thermal environment of the air moving device; processor; and A memory comprising a set of machine-readable instructions which, when executed by the processor, cause the processor to perform the method according to any one of claims 1 to 10.

13. The air moving device of claim 12, wherein the air moving device is a vacuum cleaner.

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