System and method for monitoring filter status of hvac system in a vehicle

Abstract

A system and method for monitoring a filter state of an HVAC system in a vehicle, the system including: a blower configured to intake and blow vehicle exterior air; an exterior air temperature sensor configured to determine a temperature of the vehicle exterior air intaken by the blower; an evaporator temperature sensor configured to determine a temperature of an evaporator; and a controller configured to: control an operation of the blower; analyze and determine the filter state based on temperature information determined by the exterior air temperature sensor and the evaporator temperature sensor in a state in which the vehicle exterior air intaken by the blower passes through the filter and the evaporator in sequence; and determine a filter replacement time based on the filter state.

Description

Technical Field

[0001] The present invention relates to a system and method for monitoring the filter status of a heating, ventilation and air conditioning (HVAC) system in a vehicle, configured to determine filter replacement time by analyzing the filter status of the HVAC system, thereby informing the appropriate filter replacement time. Background Technology

[0002] The vehicle is equipped with a heating, ventilation, and air conditioning (HVAC) system configured to regulate the interior air temperature by selectively supplying cool and warm air in order to provide a comfortable environment for passengers.

[0003] The HVAC system of this type of vehicle uses a blower to draw in outdoor (e.g., outside) air or indoor (e.g., inside) air, producing cool or warm air, for example, by heating or cooling the outside or inside air, and supplies the cool or warm air to the vehicle interior. The HVAC system supplies cool air in the summer to keep the vehicle interior cool, and warm air in the winter to keep the vehicle interior warm.

[0004] A typical vehicle HVAC system cools or heats air by expelling it into the vehicle interior through heat exchange with refrigerant or coolant in an evaporator or heater core installed in the HVAC housing.

[0005] In addition, in HVAC systems, filters are installed in the path through which the air used for cooling or heating passes to remove harmful foreign substances such as dust, exhaust fumes, pollen, and heavy metals from the air.

[0006] Recently, the generation of various environmental pollutants, such as fine dust and ultrafine dust, has increased. When such harmful substances are inhaled, they may pose a risk not only to respiratory diseases but also to other illnesses.

[0007] Therefore, filters are installed and used in HVAC systems. However, when foreign objects accumulate in the filter or mold and other organisms grow on it, HVAC performance may decline due to reduced airflow, potentially leading to various health problems. Therefore, the filter should be replaced to ensure the required level of cleanliness of the air inside the vehicle.

[0008] In particular, as the concept of vehicle use shifts from driving or travel to residential purposes, the cleanliness of the vehicle's interior air becomes even more important. Therefore, replacing filters at the appropriate time is crucial.

[0009] However, although there is a need for technology to determine filter replacement time by analyzing the condition of filters in a vehicle, thereby informing the appropriate filter replacement interval, such technology has not yet been applied to vehicles. Typically, filter replacements are performed intermittently during vehicle maintenance and other similar procedures.

[0010] To determine when it's time to replace the filter, its condition should be analyzed by acquiring and collecting information indicating its status. This requires additional sensors or devices. However, this increases vehicle costs. Summary of the Invention

[0011] This invention aims to solve the aforementioned problems associated with the prior art. The object of this invention is to provide a system and method for monitoring the filter status of a heating, ventilation, and air conditioning (HVAC) system in a vehicle, which, without the use of additional sensors or devices, can determine filter replacement time by analyzing the filter status of the HVAC system, thereby informing the driver of the appropriate filter replacement time.

[0012] The objectives of this invention are not limited to those described above, and those skilled in the art will more clearly understand other objectives of the invention not yet stated from the following detailed description. Furthermore, the objectives of this invention can be achieved by the means and combinations thereof defined in the appended claims.

[0013] In one aspect, the present invention provides a system for monitoring the filter status of a heating, ventilation, and air conditioning (HVAC) system in a vehicle, comprising: a blower configured to draw in and blow outside air from outside the vehicle; an outside air temperature sensor configured to detect the temperature of the outside air drawn in by the blower; an evaporator temperature sensor configured to detect the temperature of the evaporator; and a controller. The controller is configured to control the operation of the blower and, based on temperature information detected by the outside air drawn in by the blower sequentially passing through the filter and the evaporator, analyze and determine the filter status, thereby determining the filter replacement time.

[0014] In one embodiment, the system may further include an information output device configured to output filter status information, including filter replacement request information, when the controller determines that the current filter status corresponds to a filter replacement time.

[0015] In another embodiment, the filter replacement request information may be information that provides guidance on replacing the filter, requests to replace the filter, or warns that the filter needs to be replaced.

[0016] In another embodiment, the controller may be configured to perform or enter a filter check mode, and the controller may be configured to analyze the filter status based on temperature information detected by an external air temperature sensor and an evaporator temperature sensor when the vehicle ignition is off and the filter check mode is in operation.

[0017] In another embodiment, the controller may be configured to analyze the filter status when the vehicle ignition is off, in a filter check mode, with the blower running and the HVAC mode controlled to full outside air mode.

[0018] In another embodiment, the controller may be configured to enter filter check mode only if heating or cooling has been performed before the vehicle ignition is turned off.

[0019] In another embodiment, the controller may be configured to operate the blower when the state of charge (SoC) of the vehicle battery is not less than (i.e., equal to or greater than) a predetermined SoC when entering the filter check mode.

[0020] In another embodiment, when the controller enters filter check mode, causing outside air drawn in by the blower to pass sequentially through the filter and evaporator, the controller can obtain information indicating the filter status based on the initial evaporator temperature detected by the evaporator temperature sensor when the filter check mode is activated, the evaporator temperature detected by the evaporator temperature sensor as the temperature at which it no longer changes after changing from the initial evaporator temperature (i.e., the convergence temperature), the convergence time required for the evaporator temperature to reach the convergence temperature after changing from the initial evaporator temperature (as detected by the evaporator temperature sensor), and the outside air temperature detected by the outside air temperature sensor. The controller can also be configured to determine the filter replacement time based on the obtained information indicating the filter status.

[0021] In another embodiment, the controller may be configured to determine, based on the initial evaporator temperature, the convergence temperature, the convergence time, and the outside air temperature, the thermal time constant τ at which the evaporator temperature reaches the convergence temperature after changing from the initial evaporator temperature under the current outside air temperature conditions, as information representing the filter state. The controller may also be configured to determine that the current filter state corresponds to a filter replacement time when the thermal time constant is not less than (i.e., equal to or greater than) a predetermined value.

[0022] In another embodiment, the thermal time constant can be determined based on the initial evaporator temperature, convergence temperature, convergence time, and outside air temperature, according to the following expression 1:

[0023] [Expression 1]

[0024]

[0025] Where τ represents the thermal time constant, Tout T represents the outside air temperature. EVA T represents the initial evaporator temperature. time ΔT represents the convergence temperature, and ΔTime represents the convergence time.

[0026] On the other hand, the present invention provides a method for monitoring the filter status of a heating, ventilation and air conditioning (HVAC) system in a vehicle, comprising the following steps: initiating a filter inspection mode by a controller; when the filter inspection mode is activated, operating a blower by the controller to draw in and blow out outside air; as the outside air drawn in by the blower passes sequentially through the filter and the evaporator, acquiring temperature information by the controller through an outside air temperature sensor configured to detect the temperature of the outside air and an evaporator temperature sensor configured to detect the temperature of the evaporator; analyzing the filter status by the controller based on the acquired temperature information; and determining the filter replacement time by the controller based on the filter status.

[0027] In one embodiment, the method may further include: when the controller determines that the current filter status corresponds to a filter replacement time, the controller controls the operation of the information output device to output filter status information, including filter replacement request information.

[0028] In another embodiment, the filter replacement request information may be information that provides guidance on replacing the filter, requests to replace the filter, or warns that the filter needs to be replaced.

[0029] In another embodiment, the controller may be configured to enter a filter check mode when the vehicle ignition is off, so that the blower is running, and analyze the filter status based on temperature information detected by an external air temperature sensor and an evaporator temperature sensor.

[0030] In another embodiment, the controller may be configured to analyze the filter status when the vehicle ignition is off, in a filter check mode with the blower running and the HVAC mode controlled to full outside air mode.

[0031] In another embodiment, the controller may be configured to enter filter check mode only if heating or cooling has been performed before the vehicle ignition is turned off.

[0032] In another embodiment, the controller may be configured to operate the blower when the state of charge (SoC) of the vehicle battery is not less than (i.e., equal to or greater than) a predetermined SoC when entering the filter check mode.

[0033] In another embodiment, the controller may be configured to obtain information indicating the filter status as outside air drawn in by the blower sequentially passes through the filter and evaporator, based on the initial evaporator temperature detected by the evaporator temperature sensor when the filter check mode is entered (i.e., when the filter check mode is activated), the evaporator temperature detected by the evaporator temperature sensor that no longer changes after changing from the initial evaporator temperature (i.e., the convergence temperature), the convergence time required for the evaporator temperature to reach the convergence temperature after changing from the initial evaporator temperature, as detected by the evaporator temperature sensor, and the outside air temperature detected by the outside air temperature sensor. The controller may also be configured to determine the filter replacement time based on the obtained information indicating the filter status.

[0034] In another embodiment, the controller may be configured to determine, based on the initial evaporator temperature, the convergence temperature, the convergence time, and the outside air temperature, the thermal time constant τ at which the evaporator temperature reaches the convergence temperature after changing from the initial evaporator temperature under the current outside air temperature conditions, as information representing the filter state. The controller may also be configured to determine that the current filter state corresponds to a filter replacement time when the thermal time constant is not less than (i.e., equal to or greater than) a predetermined value.

[0035] In another embodiment, the thermal time constant can be determined based on the initial evaporator temperature, convergence temperature, convergence time, and outside air temperature, according to the following expression 1:

[0036] [Expression 1]

[0037]

[0038] Where τ represents the thermal time constant, T out T represents the outside air temperature. EVA T represents the initial evaporator temperature. time ΔT represents the convergence temperature, and ΔTime represents the convergence time.

[0039] Other aspects and embodiments of the invention will be discussed below.

[0040] The above and other features of the present invention will be discussed below. Attached Figure Description

[0041] The above and other features of the invention are described in detail with reference to some exemplary embodiments of the invention shown in the accompanying drawings, which are given hereinafter by way of illustration only and therefore do not limit the invention, wherein:

[0042] Figure 1 This is a diagram illustrating the main configurations of both a filter condition monitoring system and a heating, ventilation, and air conditioning (HVAC) system according to an embodiment of the present invention;

[0043] Figure 2 This is a block diagram illustrating the configuration of a filter status monitoring system according to an embodiment of the present invention;

[0044] Figure 3 This is a graph showing the change in airflow through the filter according to the filter state in this invention;

[0045] Figure 4 This is a diagram illustrating an example where, in this invention, the evaporator temperature converges to a specific temperature after the filter status is adjusted according to the HVAC system's cooling operation.

[0046] Figure 5 This is a diagram illustrating an example where, in this invention, the evaporator temperature converges to a specific temperature based on the filter state after heating is performed according to the HVAC system.

[0047] Figure 6 This is a flowchart illustrating the filter status monitoring process according to an embodiment of the present invention; and

[0048] Figure 7 This is a diagram illustrating some examples of the thermal time constants calculated in this invention.

[0049] It should be understood that the accompanying drawings are not necessarily drawn to scale, but rather present a simplified representation of various features illustrating the basic principles of the invention. Specific design features of the invention disclosed herein, including, for example, specific dimensions, orientations, positions, and shapes, will be determined in part by the particular intended application and environment of use.

[0050] In the figures, reference numerals throughout the various figures always denote the same or equivalent parts of the invention. Detailed Implementation

[0051] The specific structural or functional descriptions provided for the embodiments of the present invention disclosed herein are merely illustrative examples. The embodiments of the present invention can be implemented in various forms. Furthermore, the present invention should not be construed as limited to the embodiments described herein, and it should be understood that the present invention includes all variations, equivalents, or alternatives that fall within the spirit and scope of the present invention.

[0052] It should be understood that although terms such as "first" and "second" may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a "first" element discussed below may be referred to as a "second" element without departing from the scope of the invention. Similarly, a "second" element may also be referred to as a "first" element.

[0053] When one element is "connected" or "linked" to another element, it should be understood that the element can be directly connected or linked to the other element, or that there may be other elements in between. Conversely, when one element is "directly connected" or "directly linked" to another element, it should be understood that there are no other elements in between. Other expressions describing the relationship between constituent elements, such as "between" and "immediately between," or "adjacent to" and "directly adjacent to," should be interpreted in a similar manner.

[0054] Throughout this specification, the same reference numerals denote the same elements. It should be noted that the terminology used herein is for illustrative purposes only and is not intended to limit the invention. Incidentally, unless explicitly used otherwise, singular expressions include plural meanings. In this application, the terms "comprising" and / or "including" are intended to express the presence of the stated constituent elements, steps, operations, and / or devices, and do not exclude the presence or addition of other constituent elements, steps, operations, and / or devices. When a component, device, element, etc., of the present invention is described as having a purpose or performing an operation, function, etc., that component, device, or element should be considered herein as "configured" to satisfy that purpose or perform that operation or function.

[0055] This invention relates to a system and method for monitoring the status of filters in a vehicle's heating, ventilation, and air conditioning (HVAC) system. The system and method for monitoring filter status do not require additional sensors or devices, but can determine when filters need to be replaced by analyzing the status of the HVAC system's filters, thereby informing the driver of the appropriate filter replacement time.

[0056] In this invention, the filter status is analyzed and estimated based on changes in physical quantities, including changes in the airflow through the filter and changes in the heat exchange of the evaporator (EVA) based on the changes in airflow.

[0057] Figure 1 This is a diagram illustrating the configuration of both a filter status monitoring system and an HVAC system according to an embodiment of the present invention. Figure 2 This is a block diagram illustrating the configuration of a filter status monitoring system according to an embodiment of the present invention.

[0058] The filter status monitoring system according to an embodiment of the present invention may include: a blower 10 configured to draw in outdoor or external air and blow the drawn-in air to an evaporator 30; an external air temperature sensor 2 configured to detect or determine the temperature of the external air drawn in by the blower 10; and an evaporator temperature sensor 3 configured to detect or determine the temperature of the evaporator 30 disposed at the rear end of the filter 20.

[0059] Furthermore, the filter condition monitoring system according to an embodiment of the present invention may also include a controller 4 configured to control the operation of the blower 10 and to analyze and estimate (i.e. determine) the condition of the filter 20 based on temperature information detected by the external air temperature sensor 2 and the evaporator temperature sensor 3, thereby determining the filter replacement time.

[0060] Determining the filter replacement time means determining whether the filter needs to be replaced at any given time based on the analyzed and estimated filter condition (i.e., whether the current time is the filter replacement time).

[0061] Furthermore, the filter status monitoring system according to an embodiment of the present invention may also include an information output device 5, which is configured to be controlled by the controller 4 and output filter status information including filter replacement request information.

[0062] In one example, a filter replacement request message could indicate that a filter needs to be replaced and provide guidance, a request to replace the filter, or a warning that a filter replacement is necessary. In addition to the filter replacement request message, the filter status information may optionally include supplementary information indicating or suggesting the analyzed and estimated filter status, as well as information provided in connection with the filter replacement.

[0063] In the configuration of the above embodiment, the blower 10 is a typical vehicle HVAC blower, configured to draw in interior or exterior air supplied to the vehicle interior and blow the drawn-in air to the HVAC housing 1 for cooling and heating in the HVAC system. The filter 20 monitored in this invention is an HVAC filter, configured to remove foreign matter contained in the air supplied to the vehicle interior for cooling and / or heating.

[0064] In this invention, information representing the state of the HVAC filter is obtained by analyzing and estimating the state of the HVAC filter. The filter replacement time is determined based on this information. In one example, the information representing the filter state can be the thermal time constant τ.

[0065] In an HVAC system, filter 20 can be installed on the front side of the blower, i.e., upstream of blower 10, based on the airflow direction, or as... Figure 1 As shown, it can be installed on the rear end side of the blower, that is, the downstream side of the blower 10. Figure 1 An example of a filter 20 installed on the rear side of the blower 10 and the front side of the evaporator 30, with reference to the airflow direction in the HVAC system.

[0066] External air temperature sensor 2 is a temperature sensor configured to detect the temperature of external air drawn in by blower 10. External air temperature sensor 2 is electrically connected to controller 4. External air temperature sensor is configured to output an electrical signal corresponding to the external air temperature and to input or send this electrical signal to controller 4.

[0067] like Figure 1 As shown, the external air temperature sensor 2 can be installed on the front end of the blower 10 (upstream of the blower 10) and on the channel through which the external air drawn in by the blower 10 passes.

[0068] Evaporator temperature sensor 3 is a temperature sensor installed on the evaporator 30 of the HVAC system to detect the temperature of the evaporator 30. Evaporator temperature sensor 3 is electrically connected to controller 4 to output an electrical signal corresponding to the evaporator temperature and to input or send the electrical signal to controller 4.

[0069] Evaporator 30 is an evaporator used in a conventional HVAC system, configured to exchange heat between refrigerant and air used for HVAC. Evaporator 30 is a key component of an air conditioning system used for indoor (e.g., interior) cooling. Thus, while evaporating the refrigerant expanded by the expansion valve, evaporator 30 utilizes the latent heat of vaporization of the refrigerant to cool the air supplied to the vehicle interior.

[0070] The air surrounding the evaporator 30 is cooled by the refrigerant passing inside the evaporator 30. The cooled air passing around the evaporator 30 is supplied to the vehicle interior, thereby providing indoor cooling.

[0071] Reference Figure 1 In the HVAC housing 1, the evaporator 30 is arranged upstream (front end) with reference to the air flow direction, and the internal condenser 50, which serves as an auxiliary heater, and the electric heater 60, which serves as the main heater, are arranged downstream (rear end of the evaporator) with reference to the air flow direction.

[0072] The internal condenser 50 is a heat exchanger installed within the HVAC housing 1 to facilitate heat exchange between the refrigerant and the air. The internal condenser 50 is connected to the refrigerant outlet of the compressor (not shown) via a refrigerant line. Therefore, refrigerant compressed by the compressor to a high temperature and pressure can be supplied to the internal condenser 50 via the refrigerant line.

[0073] The refrigerant, compressed to a high temperature and pressure by the compressor and passing through the internal condenser 50, exchanges heat with the air blown by the blower 10 through the area surrounding the internal condenser 50. During the heat exchange, the air is heated by the high-temperature refrigerant, and the heated air is supplied to the vehicle interior, thereby providing indoor heating.

[0074] The electric heater 60 may be a positive temperature coefficient (PTC) heater, configured to generate heat while consuming battery power. The electric heater 60 may be installed within the HVAC housing 1 downstream of the internal condenser 50 (on the rear end side of the internal condenser), with the airflow direction as a reference.

[0075] exist Figure 1 In the attached diagram, reference numeral "40" indicates a temperature gate (temperature control gate). Temperature gate 40 regulates the amount of air passing solely around the evaporator 30 and the amount of air passing sequentially around the evaporator 30, the internal condenser 50, and the electric heater 60.

[0076] When the signals from the external air temperature sensor 2 and the evaporator temperature sensor 3 are input to the controller 4, the controller 4 can obtain the external air temperature and evaporator temperature from the signals of the two temperature sensors respectively, as temperature information for determining the filter status.

[0077] In this invention, the controller 4 determines the thermal time constant τ based on the temperature information detected by two temperature sensors, and uses the determined thermal time constant τ to determine the filter replacement time.

[0078] Furthermore, when it is determined that filter 20 should be replaced based on the thermal time constant τ, controller 4 controls the operation of information output device 5 to provide the driver with filter status information, including filter replacement request information.

[0079] In other words, when it is determined that the filter needs to be replaced, the controller 4 outputs a control signal to output filter status information. Based on the control signal output from the controller 4, the information output device 5 can output filter status information, including information that provides guidance for filter replacement, requests filter replacement, or warns that the filter needs to be replaced, i.e., filter replacement request information.

[0080] In this invention, the information output device 5 can be a device installed in the vehicle for outputting filter status information to, for example, the driver. Any device can be used as the information output device without any limitation, as long as the device can operate in the vehicle to notify the driver that the filter needs to be replaced.

[0081] For example, such a device could be a warning light configured to illuminate a dashboard panel to warn or notify that a filter needs to be replaced, or a display device configured to display a message guiding or requesting filter replacement, or other predetermined form of visual information. Alternatively, the device could be an audio output device configured to output audible information guiding or requesting filter replacement.

[0082] The filter status monitoring process will be described in detail below.

[0083] Figure 3 This is a graph showing the change in airflow through the filter according to the filter state of the present invention. Figure 3 In the diagram, the thickness of the arrows indicates the flow level or flow rate. In other words, a thick arrow indicates a relatively high flow rate, while a thin arrow indicates a relatively low flow rate.

[0084] In the initial filter state (i.e., the new filter state), the resistance in filter 20 is low, therefore, the airflow through filter 20 is high, such as... Figure 3 As shown in the image above.

[0085] However, in the contaminated filter state, due to the presence of foreign objects in filter 20, the resistance in filter 20 is relatively high. Therefore, the airflow through filter 20 is lower than in the initial filter state, such as... Figure 3 As shown in the image below.

[0086] Figure 4 This is a diagram illustrating an example where, in this invention, the evaporator temperature converges to a specific temperature after the filter status is adjusted according to the HVAC system's cooling operation. (See diagram for example.) Figure 4 As shown, in the initial filter state (new filter state) after cooling, the air flow rate through filter 20 is relatively high. Therefore, when the air flowing out of filter 20 passes around evaporator 30, the time required for the evaporator temperature to converge to a specific temperature (=t_2-t_1) is relatively short.

[0087] On the other hand, in the state of the contaminated filter (the state of the used filter), the airflow through filter 20 is relatively low. Therefore, when the air flowing out of filter 20 passes around evaporator 30, the time required for the evaporator temperature to converge to a specific temperature (=t_3-t_1) is longer than in the initial filter state (t_2-t_1). <t_3-t_1)。

[0088] In this invention, evaporator temperature convergence means that the evaporator temperature gradually changes to a predetermined temperature and then remains at that predetermined temperature without changing further. Furthermore, the temperature at which the evaporator temperature converges, i.e., the predetermined temperature at which the evaporator temperature remains unchanged, is defined as the "convergence temperature".

[0089] Furthermore, the evaporator temperature at the initial moment of entering the filter check mode described below, i.e., the initial temperature of the evaporator in the filter check mode, is defined as the "initial evaporator temperature". The time required for the evaporator temperature to change from the initial evaporator temperature to the convergence temperature, i.e., the temperature at which the evaporator temperature no longer changes, is defined as the "convergence time".

[0090] Although Figure 4The convergence temperature is represented as the outside air temperature, but the evaporator temperature does not always converge to the outside air temperature. When the evaporator 30 reaches thermal equilibrium and thus has a temperature state where the evaporator temperature no longer changes, this temperature state can be said to be the convergence state of the evaporator temperature. The evaporator temperature in this convergence state is the convergence temperature.

[0091] Figure 4 This shows the change in evaporator temperature during the filter check mode after cooling begins. After cooling begins, the evaporator temperature gradually increases from the initial evaporator temperature at the moment the filter check mode is entered, i.e., the initial evaporator temperature, and thus reaches the convergence temperature.

[0092] In an embodiment of the present invention, the thermal time constant τ can be used as the external air temperature T. out Initial evaporator temperature T EVA Convergence temperature T time The convergence time ΔTime is calculated using the following expression 1.

[0093] [Expression 1]

[0094]

[0095] Where τ represents the thermal time constant, T out This indicates the outdoor air temperature in filter check mode, T. EVA This indicates the initial evaporator temperature in filter check mode. Figure 4 In the example, the initial evaporator temperature T EVA This is the evaporator temperature at time t_1. Furthermore, T... time ΔT represents the convergence temperature, and ΔTime represents the convergence time.

[0096] Figure 5 This is a diagram illustrating an example where, in this invention, the evaporator temperature converges to a specific temperature after the filter status is adjusted according to the HVAC system's heating operation. Figure 5 This shows the change in evaporator temperature during filter check mode after heating begins. Unlike cooling, after heating begins, the evaporator temperature gradually decreases from the initial evaporator temperature upon entering filter check mode, thus reaching the convergence temperature.

[0097] Even after heating as described above, the convergence time required for the evaporator temperature to change from the initial evaporator temperature to the convergence temperature is longer for used filters (contaminated filter state) than for new filters (initial filter state).

[0098] Thus, the airflow rate through filter 20 after cooling or heating varies depending on the filter's condition. Consequently, the time required for the evaporator temperature to change from the initial evaporator temperature to the convergence temperature, i.e., the convergence time, varies depending on the filter's condition.

[0099] As the filters in the HVAC system continue to become contaminated, the resistance in filter 20 gradually increases, thus gradually reducing the airflow through filter 20. When the airflow decreases, the heat exchange capacity Q of the evaporator 30 decreases.

[0100] After the vehicle's ignition is turned off while cooling or heating is in operation, and outdoor air passes sequentially through filter 20 and evaporator 30 due to the operation of blower 10, the convergence state of evaporator 30 reaching thermal equilibrium is delayed as the heat exchange rate Q of evaporator 30 decreases. Therefore, the convergence time required for the evaporator temperature to change from the initial evaporator temperature to the convergence temperature becomes longer.

[0101] In this invention, the thermal equilibrium delay time characteristic of the evaporator 30 is converted into a physical quantity, namely, the thermal time constant τ when the evaporator temperature changes from the initial evaporator temperature to the convergence temperature under the current outdoor air temperature conditions. The contamination state of the filter 20 is determined based on the converted physical quantity. The thermal time constant τ can be understood as a value obtained by converting the heat exchange quantity Q of the evaporator 30 into time.

[0102] Tables 1 and 2 below show a comparison of the thermal time constant τ between a new filter (initial filter state) and a used filter (contaminated filter state). The example in Table 2 may be an example of a filter that needs to be replaced.

[0103] [Table 1]

[0104]

[0105] [Table 2]

[0106]

[0107] In the state of the two filters 20, the two filters 20 are equal in terms of the external air temperature detected by the external air temperature sensor 2, the initial evaporator temperature detected by the evaporator temperature sensor 3, and the convergence temperature at which the evaporator temperature detected by the evaporator temperature sensor 3 converges and no longer changes.

[0108] However, since the two filters 20 are in different states, they also differ in the time required for the evaporator temperature to change from the initial evaporator temperature to the convergence temperature, i.e., the convergence time. Therefore, the thermal time constant τ calculated by Expression 1 varies depending on the filter state and increases with the increase of filter usage time.

[0109] Figure 6 This is a flowchart illustrating a filter status monitoring process according to an embodiment of the present invention. Figure 7 This is a diagram illustrating some examples of the thermal time constants calculated in this invention. The filter condition monitoring process is described step-by-step below.

[0110] In this invention, controller 4 is configured to execute a filter check mode. Controller 4 may include a processor and a memory. The memory may store, for example, a set of rules or algorithms for executing the filter check mode, and the processor may implement or execute the set of rules or algorithms. When the vehicle's ignition is turned off after the HVAC system has been operating for cooling or heating (S1 and S2), controller 4 is set or configured to enter the filter check mode (S3).

[0111] When the controller 4 is in or in the filter check mode (i.e., the filter check mode is on), the controller 4 determines whether the battery's state of charge (SoC) is equal to or greater than a predetermined value (e.g., 30%) (S4).

[0112] When the battery's SoC is less than a predetermined SoC, the controller 4 shuts off the filter check mode (S5). On the other hand, when the battery's SoC is equal to or greater than the predetermined SoC, the controller 4 starts the blower 10 (S6). In this case, the controller 4 can start the blower 10 at the first stage and then control the HVAC mode to full external air mode (S7).

[0113] As described above, controller 4 operates blower 10 in filter check mode after vehicle ignition is off, and then controls the HVAC mode to full outside air mode, so that outside air passes sequentially around filter 20 and evaporator 30 while being blown by blower 10. Full outside air mode is a mode that only draws in and blows outside air without mixing with indoor air.

[0114] After entering the filter check mode, the controller 4 determines the thermal time constant τ when the evaporator temperature reaches the convergence temperature after changing from the initial evaporator temperature, based on the external air temperature detected by the external air temperature sensor 2 and the evaporator temperature detected by the evaporator temperature sensor 3 under the current external air temperature conditions.

[0115] In other words, after entering the filter check mode, the controller 4 obtains the external air temperature and evaporator temperature based on signals from the external air temperature sensor 2 and the evaporator temperature sensor 3 (S8 and S9). After entering the filter check mode, the controller 4 also monitors whether the evaporator temperature converges to a specific temperature after changing from the initial evaporator temperature (S10).

[0116] When the evaporator temperature changes from the initial evaporator temperature T EVA When the evaporator temperature reaches a predetermined temperature after a change and remains at that temperature without changing further, controller 4 determines that the evaporator temperature has converged and defines the evaporator temperature that no longer changes as the convergence temperature T. time (S11).

[0117] In addition, controller 4 will adjust the evaporator temperature from the initial evaporator temperature T. EVA The change occurs when the predetermined temperature, i.e., the convergence temperature T, is reached. time The required time is defined as the convergence time ΔTime(S12).

[0118] Subsequently, the controller 4 determines the thermal time constant τ as the evaporator temperature changes from the initial evaporator temperature and reaches the convergence temperature as information representing or indicating the filter status (S13).

[0119] In an embodiment of the invention, after determining the thermal time constant τ as described above, the controller 4 can compare the determined thermal time constant τ with a previous thermal time constant (S14). The previous thermal time constant is a thermal time constant value calculated each time the filter check mode was previously run.

[0120] After calculating the thermal time constant in the initial filter state, controller 4 recalculates the thermal time constant the next time the filter check mode is executed, in order to re-identify the filter state. Therefore, whenever the thermal time constant is calculated, controller 4 can identify the current filter state by comparing the currently calculated thermal time constant with the previously calculated thermal time constant.

[0121] For example, controller 4 can estimate filter replacement by identifying changes in the thermal time constant, i.e., a state where the thermal time constant has increased. Alternatively, controller 4 can determine if an error has occurred in the calculation of the thermal time constant by identifying a decrease in the thermal time constant or the degree of decrease in the thermal time constant. When a calculation error is determined, controller 4 can ignore the newly calculated thermal time constant and store the thermal time constant calculated in the immediately preceding filter check mode as the final value.

[0122] Furthermore, after determining the thermal time constant τ as information representing the filter state through Expression 1, the controller 4 compares the determined thermal time constant with a predetermined value (S15).

[0123] When the thermal time constant τ is determined to be equal to or greater than a predetermined value, the controller 4 determines that the filter 20 should be replaced at this time, and then outputs a control signal to output filter status information including filter replacement request information.

[0124] Therefore, based on the control signal output from the controller 4, the operation of the information output device 5 is controlled to output filter status information. In this case, filter replacement request information can be output through the information output device 5, that is, information indicating that the filter needs to be replaced, providing guidance for filter replacement, requesting filter replacement, or warning that the filter needs to be replaced (S16).

[0125] Additionally, information about the thermal time constant τ can be output via information output device 5 as information representing the analyzed and estimated filter condition. Furthermore, other given information related to filter replacement can be output.

[0126] Reference Figure 7 It can be seen that as the filter usage time increases, the thermal time constant gradually increases (τ0<τ1<τ2<…<τ). n When the thermal time constant τ is equal to or greater than a predetermined value (e.g., the filter limit value), the controller 4 determines that the filter needs to be replaced, and then the control information output device 5 operates to output a filter replacement request message. This filter replacement request message informs the driver that the current time is an appropriate time to replace the filter.

[0127] As mentioned above, with prolonged use, the amount of foreign matter accumulated in the filter gradually increases, the resistance in the filter gradually increases, and the airflow through the filter and the heat exchange capacity of the evaporator gradually decrease. Furthermore, inversely proportional to these values, the time required for the evaporator to reach thermal equilibrium, and the thermal time constant τ, gradually increase.

[0128] As can be clearly seen from the above description, the system and method for monitoring the filter status of the HVAC system in a vehicle can determine the filter replacement time by analyzing the filter status of the HVAC system without the use of additional sensors or devices, and inform the driver of the appropriate filter replacement time.

[0129] Therefore, the driver can replace the filter at appropriate times, thus keeping it in good condition at all times. This maintains the cleanliness of the air inside the vehicle and ensures passenger comfort. Furthermore, it prevents a reduction in airflow through the filter, thereby maintaining or enhancing cooling and heating performance.

[0130] The present invention has been described in detail above with reference to embodiments. However, those skilled in the art should understand that changes can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A system for monitoring the status of filters in a heating, ventilation, and air conditioning (HVAC) system in a vehicle, the system comprising: A blower, configured to draw in and blow outside air from the vehicle; An external air temperature sensor is configured to determine the temperature of the external air drawn into the vehicle by the blower; Evaporator temperature sensor, configured to determine the temperature of the evaporator; as well as The controller is configured as follows: Control the operation of the blower; With the outside air drawn in by the blower sequentially passing through the filter and evaporator, the filter status is analyzed and determined based on temperature information determined by the outside air temperature sensor and the evaporator temperature sensor; and Determine the filter replacement time based on the filter's condition.

2. The system according to claim 1, further comprising: An information output device is configured to output filter status information, including filter replacement request information, when the controller determines that the current filter status corresponds to the filter replacement time.

3. The system according to claim 2, wherein, The filter replacement request information provides guidance on replacing the filter, requests to replace the filter, or warns that the filter needs to be replaced.

4. The system according to claim 1, wherein: The controller is configured to enter filter inspection mode; and The controller is configured to enter the filter check mode and run the blower when the vehicle ignition is off, and analyze the filter status based on temperature information determined by the external air temperature sensor and the evaporator temperature sensor.

5. The system according to claim 4, wherein, The controller is configured to analyze the filter status when the vehicle ignition is off, in a filter check mode, with the blower running and the HVAC mode controlled to full external air mode.

6. The system according to claim 4, wherein, The controller is configured to enter the filter check mode only if heating or cooling has been performed before the vehicle ignition is turned off.

7. The system according to claim 4, wherein, The controller is configured to operate the blower when the state of charge (SoC) of the vehicle battery meets a predetermined SoC when entering the filter inspection mode.

8. The system according to claim 4, wherein: When the controller enters the filter check mode, causing the outside air drawn in by the blower to pass sequentially through the filter and evaporator, the controller obtains information indicating the filter status based on the following: The initial evaporator temperature at the start of the filter check mode, as determined by the evaporator temperature sensor; Convergence temperature, which is the evaporator temperature determined by the evaporator temperature sensor that no longer changes after a change from the initial evaporator temperature; The convergence time required for the evaporator temperature, as determined by the evaporator temperature sensor, to reach the convergence temperature after changing from the initial evaporator temperature; as well as The external air temperature is determined by the external air temperature sensor; and the controller is configured to determine the filter replacement time based on the obtained information indicating the filter status.

9. The system according to claim 8, wherein: The controller is configured to determine, based on the initial evaporator temperature, convergence temperature, convergence time, and external air temperature, the thermal time constant τ at which the evaporator temperature reaches the convergence temperature after changing from the initial evaporator temperature under the current external air temperature conditions, as information representing the filter status; and The controller is configured to determine the current filter state corresponding to the filter replacement time when the thermal time constant meets a predetermined value.

10. The system according to claim 9, wherein, Based on the initial evaporator temperature, convergence temperature, convergence time, and outside air temperature, the thermal time constant is determined according to the following expression 1: [Expression 1] Where τ represents the thermal time constant, T out T represents the outside air temperature. EVA T represents the initial evaporator temperature. time ΔT represents the convergence temperature, and ΔTime represents the convergence time.

11. A method for monitoring the filter status of a heating, ventilation, and air conditioning (HVAC) system in a vehicle, the method comprising the steps of: The filter check mode is initiated by the controller; Based on the filter inspection mode, the controller starts the blower to draw in and blow out outside air. Based on the fact that the outside air drawn in by the blower passes through the filter and the evaporator in sequence, the controller obtains temperature information through the outside air temperature sensor and the evaporator temperature sensor. The outside air temperature sensor is configured to determine the temperature of the outside air, and the evaporator temperature sensor is configured to determine the temperature of the evaporator. The controller analyzes the filter status based on the obtained temperature information; as well as The controller determines the filter replacement time based on the filter status.

12. The method of claim 11, further comprising the step of: When the controller determines that the current filter status corresponds to the filter replacement time, the controller controls the operation of the information output device to output filter status information, including filter replacement request information.

13. The method according to claim 12, wherein, The filter replacement request information provides guidance on replacing the filter, requests to replace the filter, or warns that the filter needs to be replaced.

14. The method according to claim 11, wherein, The controller is configured to enter the filter check mode when the vehicle ignition is off, so that the blower is running, and analyze the filter status based on temperature information determined by the external air temperature sensor and the evaporator temperature sensor.

15. The method according to claim 14, wherein, The controller is configured to analyze the filter status when the vehicle ignition is off, in a filter check mode with the blower running and the HVAC mode controlled to full external air mode.

16. The method of claim 14, wherein, The controller is configured to enter the filter check mode only if heating or cooling has been performed before the vehicle ignition is turned off.

17. The method according to claim 11, wherein, The controller is configured to operate the blower when the state of charge (SoC) of the vehicle battery meets a predetermined SoC when entering the filter inspection mode.

18. The method according to claim 11, wherein: With the outside air drawn in by the blower passing through the filter and evaporator in sequence, the controller is configured to obtain information indicating the filter status based on the following: The initial evaporator temperature at the start of the filter check mode, as determined by the evaporator temperature sensor; Convergence temperature, which is the evaporator temperature determined by the evaporator temperature sensor that no longer changes after a change from the initial evaporator temperature; The convergence time required for the evaporator temperature, as determined by the evaporator temperature sensor, to reach the convergence temperature after changing from the initial evaporator temperature; as well as The external air temperature is determined by the external air temperature sensor; and the controller is configured to determine the filter replacement time based on the obtained information indicating the filter status.

19. The method of claim 18, wherein: The controller is configured to determine, based on the initial evaporator temperature, convergence temperature, convergence time, and external air temperature, the thermal time constant τ at which the evaporator temperature reaches the convergence temperature after changing from the initial evaporator temperature under the current external air temperature conditions, as information representing the filter status; and The controller is configured to determine the current filter state corresponding to the filter replacement time when the thermal time constant meets a predetermined value.

20. The method according to claim 19, wherein, Based on the initial evaporator temperature, convergence temperature, convergence time, and outside air temperature, the thermal time constant is determined according to the following expression 1: [Expression 1] Where τ represents the thermal time constant, T out T represents the outside air temperature. EVA T represents the initial evaporator temperature. time ΔT represents the convergence temperature, and ΔTime represents the convergence time.

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