Self-calibrating engine air filter life monitoring system

Abstract

A self-calibrating method for determining the remaining useful life of an air filter in an internal combustion engine comprises: using pressure drop, airflow mass flow rate, and temperature data captured at low and elevated engine speeds to relate the pressure drop of a clean air filter to the airflow mass flow rate. The method further comprises using the clean filter relationship to establish a maximum clean air filter pressure drop at a preset maximum airflow. The method further comprises using the pressure drop, airflow mass flow rate, and temperature data captured at low and elevated engine speeds to relate the pressure drop of an in-use air filter to the airflow mass flow rate. The method further comprises using the in-use filter relationship to determine the maximum in-use air filter pressure drop at the preset maximum airflow. The method further comprises comparing the maximum clean air filter pressure drop to the in-use air filter pressure drop to determine the remaining useful life of the in-use air filter.

Description

Technical Field

[0001] The present disclosure relates to self-calibration of an internal combustion engine (ICE) air filter life monitoring system and determination of air filter service life. Background Art

[0002] Air filters remove particulate matter from the airstream. For example, air filters used in internal combustion engines filter particulate matter before air is introduced into the combustion chamber. Over time, particulate matter accumulates and clogs the filter. A clogged air filter can lead to inefficient engine operation and should be replaced.

[0003] Such air filters have historically been monitored indirectly to determine when they should be replaced. For example, the distance a vehicle has traveled since its last air filter change is often used as a means of determining when to replace the air filter. Using distance traveled as the basis for this determination relies primarily on a correlation between the distance traveled by the vehicle and the rate at which the vehicle's air filter becomes clogged with particles. However, the actual correlation between the distance traveled by the vehicle and the degree of filter clogging is widely affected by factors such as the amount of particulate matter in the vehicle's operating environment. In arid and semi-arid regions, particle concentrations can be several orders of magnitude higher.

[0004] Therefore, methods for determining when to replace a vehicle's air filter based on the distance traveled by the vehicle can be inaccurate. Therefore, it would be desirable to provide methods and systems for determining the remaining useful life of an air filter based on factors that are more representative of the degree of filter clogging. Various methods have been developed to determine the useful life of an air filter. However, these methods often require expensive calibration testing to generate a calibrated relationship for each vehicle-engine combination. Summary of the Invention

[0005] A method for self-calibrating an internal combustion engine (ICE) air filter life monitoring system regulated by an electronic controller includes acquiring a first clean air filter data set defined by a first clean air filter pressure, a first clean air filter airflow mass flow rate, and a first clean air filter temperature at a low ICE speed. The first clean air filter data set is acquired by regulating and interrogating corresponding ICE sensors via the electronic controller. The method also includes acquiring a second clean air filter data set defined by a second clean air filter pressure, a second clean air filter airflow mass flow rate, and a second clean air filter temperature at an increased ICE speed. The second clean air filter data set is acquired by regulating and interrogating corresponding ICE sensors via the electronic controller. The method also includes establishing a relationship between clean air filter pressure drop and airflow mass flow rate using the acquired first and second clean air filter data sets via the electronic controller. The method also includes determining a maximum clean air filter pressure drop of the clean air filter at a preset maximum airflow mass flow rate using the clean air filter relationship.

[0006] The method also includes obtaining a first in-use air filter data set defined by a first in-use air filter pressure, a first in-use air filter airflow mass flow rate, and a first in-use air filter temperature at a low ICE speed. The first in-use air filter data set is obtained by adjusting and interrogating corresponding ICE sensors via an electronic controller. The method also includes obtaining a second in-use air filter data set defined by a second in-use air filter pressure, a second in-use air filter airflow mass flow rate, and a second in-use air filter temperature at the elevated ICE speed. The second in-use air filter data set is obtained by adjusting and interrogating corresponding ICE sensors via an electronic controller. The method also includes establishing a relationship between an in-use air filter pressure drop and an airflow mass flow rate using the obtained first and second in-use air filter data sets via the electronic controller. The method also includes determining a maximum in-use air filter pressure drop of the in-use air filter at the preset maximum airflow mass flow rate using the in-use air filter relationship.

[0007] The method further includes comparing, via the electronic controller, a maximum air filter pressure drop of the in-use air filter with a maximum pressure drop of the clean air filter to calculate a difference between the in-use air filter pressure drop and the clean air filter pressure drop at a predetermined maximum airflow mass flow rate. Furthermore, the method includes determining and storing, via the electronic controller, a remaining useful life of the in-use air filter corresponding to the calculated pressure drop difference.

[0008] The method may also include determining atmospheric pressure downstream of the clean air filter with the ICE off. In the same embodiment, the method may also include determining a clean air filter pressure at a low ICE speed, and further determining a clean air filter pressure drop by calculating the difference between the determined atmospheric pressure downstream of the clean air filter with the ICE off and the determined clean air filter pressure at the low ICE speed. The clean air filter pressure drop may be corrected to a reference temperature and pressure. Establishing the clean air filter relationship may also include using the determined clean air filter pressure drop at the first clean air filter airflow mass flow rate.

[0009] Establishing the clean air filter relationship can be accomplished in two stages. Establishing the clean air filter relationship can specifically include, in a first stage, using the acquired clean air filter first and second data sets and the clean air filter pressure drop to establish a rough clean air filter relationship to estimate the second clean air filter pressure drop at the second clean air filter airflow mass flow rate. Establishing the relationship can also include generating a first quadratic equation to fit the second clean air filter pressure drop and the second clean air filter airflow mass flow rate to the rough clean air filter relationship. Additionally, establishing the relationship can include, in a second stage, using the new first and second data sets and the first quadratic equation to establish a final clean air filter relationship to estimate the final second clean air filter pressure drop at the final second clean air filter airflow mass flow rate. Establishing the clean air filter relationship can also include generating a second quadratic equation to fit the final second clean air filter pressure drop and the final second clean air filter airflow mass flow rate to the final clean air filter relationship.

[0010] Establishing the rough and final clean air filter relationship may include collecting a plurality of data pairs to refine the relationship between clean air filter pressure drop and airflow mass flow rate. Establishing the rough and final clean air filter relationship may also include organizing the collected plurality of data pairs into a predetermined number of bins. Establishing the rough and final clean air filter relationship may also include averaging the data pairs in each corresponding bin. Establishing the rough and final clean air filter relationship may further include using the averaged clean air filter data pairs to generate each of a first quadratic equation for the rough clean air filter relationship and a second quadratic equation for the final clean air filter relationship.

[0011] Generating the second quadratic equation may include determining polynomial coefficients of the second quadratic equation. Additionally, determining the maximum air filter pressure drop of the clean air filter may include using a final clean air filter relationship.

[0012] The method may further include determining the atmospheric pressure downstream of the in-use air filter with the ICE off, and determining the in-use air filter pressure at a low ICE speed. The method may further include determining a pressure drop across the in-use air filter by calculating the difference between the determined atmospheric pressure downstream of the in-use air filter with the ICE off and the determined in-use air filter pressure at a low ICE speed. The in-use air filter pressure drop may be corrected to a reference temperature and pressure. Furthermore, establishing the in-use air filter relationship may further include using the in-use air filter pressure drop determined at a first in-use air filter airflow mass flow rate.

[0013] Establishing the in-use air filter relationship can be accomplished in two stages. Establishing the in-use air filter relationship may include, in a first stage, using the acquired first and second data sets of the in-use air filter and the pressure drop of the in-use air filter to establish a rough in-use air filter relationship to estimate the second in-use air filter pressure drop at the second in-use air filter mass flow rate. Establishing the relationship may also include generating a first quadratic equation to fit the second in-use air filter pressure drop and the second in-use air filter mass flow rate to the rough in-use air filter relationship. Establishing the relationship may also include, in a second stage, establishing a final in-use air filter relationship using new first and second in-use air filter data sets and the first quadratic equation to estimate the new second in-use air filter pressure drop at the second in-use air filter mass flow rate. Establishing the in-use air filter relationship may also include generating a second quadratic equation to fit the new in-use second air filter pressure drop and the second in-use air filter mass flow rate to the final in-use air filter relationship.

[0014] Establishing the rough and final in-use air filter relationship may include collecting a plurality of data pairs to refine the relationship between in-use air filter pressure drop and airflow mass flow rate. Establishing the rough and final in-use air filter relationship may also include organizing the plurality of collected data pairs into a predetermined number of bins and averaging the data pairs in each corresponding bin. Establishing the rough and final in-use air filter relationship may also include using the averaged in-use air filter data pairs to generate each of the first quadratic equation for the rough in-use air filter relationship and the second quadratic equation for the final in-use air filter relationship.

[0015] According to the method, generating the second quadratic equation may include determining polynomial coefficients of the second quadratic equation.Also, according to the method, determining the maximum air filter pressure drop of the in-use air filter may include using an end-in-use air filter relationship.

[0016] The method may further include setting a sensing signal when the calculated pressure drop difference is equal to or greater than a predetermined value. The predetermined value may be in the range of 2.3-2.5 kPa.

[0017] Another embodiment of the present disclosure relates to a self-calibrating air filter life monitoring system for an internal combustion engine (ICE). The air filter life monitoring system includes an air intake system having an air filter in fluid communication with the ICE. The air filter life monitoring system also includes an electronic controller configured to determine the remaining useful life of the air filter according to the method described above.

[0018] Another embodiment of the present disclosure is directed to a non-transitory computer-readable medium having executable instructions stored thereon for self-calibration of an internal combustion engine (ICE) air filter life monitoring system.

[0019] The present invention also includes the following solutions:

[0020] Solution 1. A method for self-calibration of an internal combustion engine (ICE) air filter life monitoring system having an electronic controller, the method comprising:

[0021] acquiring a first clean air filter data set defined by a first clean air filter pressure, a first clean air filter airflow mass flow rate, and a first clean air filter temperature via conditioning and interrogating corresponding sensors at a low ICE speed;

[0022] acquiring a second clean air filter data set defined by a second clean air filter pressure, a second clean air filter airflow mass flow rate, and a second clean air filter temperature via conditioning and interrogating the respective sensors at an elevated ICE speed;

[0023] establishing, via the electronic controller, a relationship between a clean air filter pressure drop and an airflow mass flow rate using the acquired clean air filter first data set and the acquired second data set;

[0024] determining a maximum clean air filter pressure drop of the clean air filter at a predetermined maximum airflow mass flow rate using the clean air filter relationship;

[0025] acquiring a first in-use air filter data set defined by a first in-use air filter pressure, a first in-use air filter airflow mass flow rate, and a first in-use air filter temperature via conditioning and interrogating the respective sensors at the low ICE speed;

[0026] acquiring a second in-use air filter data set defined by a second in-use air filter pressure, a second in-use air filter airflow mass flow rate, and a second in-use air filter temperature via conditioning and interrogating the respective sensors at the elevated ICE speed;

[0027] establishing, via the electronic controller, a relationship between an in-use air filter pressure drop and an airflow mass flow rate using the acquired first and second data sets of the in-use air filter;

[0028] determining a maximum in-use air filter pressure drop of the in-use air filter at the predetermined maximum airflow mass flow rate using the in-use air filter relationship;

[0029] comparing, via the electronic controller, the maximum air filter pressure drops of the clean air filter and the in-use air filter to calculate a difference in the in-use air filter pressure drop relative to the clean air filter pressure drop at the predetermined maximum airflow mass flow rate; and

[0030] The remaining useful life of the in-use air filter corresponding to the calculated pressure drop difference is determined and stored via the electronic controller.

[0031] Solution 2. The method according to Solution 1, further comprising:

[0032] determining atmospheric pressure downstream of the clean air filter with the ICE turned off;

[0033] determining a clean air filter pressure at the low ICE speed; and

[0034] determining a clean air filter pressure drop via calculating a difference between a determined atmospheric pressure downstream of the clean air filter with the ICE off and a determined clean air filter pressure at the low ICE speed;

[0035] Wherein establishing the clean air filter relationship further comprises using a clean air filter pressure drop determined at the first clean air filter airflow mass flow rate.

[0036] Option 3. The method of Option 2, wherein establishing the clean air filter relationship is accomplished in two stages and comprises:

[0037] establishing, in a first stage, a coarse clean air filter relationship using the acquired clean air filter first and second data sets and the clean air filter pressure drop to estimate the second clean air filter pressure drop at the second clean air filter airflow mass flow rate;

[0038] generating a first quadratic equation to fit the second clean air filter pressure drop and the second clean air filter airflow mass flow rate to the coarse clean air filter relationship;

[0039] establishing in a second stage a final clean air filter relationship using the new first and second air filter data sets and the first quadratic equation to estimate a final second clean air filter pressure drop at a final second clean air filter airflow mass flow rate; and

[0040] A second quadratic equation is generated to fit the final second clean air filter pressure drop and the final second clean air filter airflow mass flow rate to the final clean air filter relationship.

[0041] Option 4. The method according to Option 3, wherein establishing the rough clean air filter relationship and the final clean air filter relationship comprises:

[0042] Collect multiple data pairs to refine the clean air filter pressure drop versus airflow mass flow rate relationship;

[0043] organizing the collected plurality of data pairs into a predetermined number of bins;

[0044] averaging the data pairs in each corresponding bin; and

[0045] Each of the first quadratic equation of the rough clean air filter relationship and the second quadratic equation of the final clean air filter relationship is generated using the average data pair of the clean air filter.

[0046] Scheme 5. The method according to Scheme 4, wherein:

[0047] Generating the second quadratic equation includes determining polynomial coefficients of the second quadratic equation; and

[0048] Determining the maximum air filter pressure drop of the clean air filter includes using a final clean air filter relationship.

[0049] Solution 6. The method according to solution 1, further comprising:

[0050] determining atmospheric pressure downstream of the in-use air filter with the ICE turned off;

[0051] determining an in-use air filter pressure at said low ICE speed; and

[0052] determining an in-use air filter pressure drop by calculating a difference between an atmospheric pressure downstream of the in-use air filter determined with the ICE off and an in-use air filter pressure determined at the low ICE speed;

[0053] Wherein, establishing the in-use air filter relationship further comprises using an in-use air filter pressure drop determined at the first in-use air filter airflow mass flow rate.

[0054] Option 7. The method according to Option 6, wherein establishing the in-use air filter relationship is completed in two stages and comprises:

[0055] establishing a coarse in-use air filter relationship in a first stage using the acquired first and second in-use air filter data sets and the in-use air filter pressure drop to estimate the second in-use air filter pressure drop at the second in-use air filter airflow mass flow rate;

[0056] generating a first quadratic equation to fit the second in-use air filter pressure drop and the second in-use air filter airflow mass flow rate to the coarse in-use air filter relationship;

[0057] establishing in a second stage a final in-use air filter relationship using the new first and second in-use air filter data sets and the first quadratic equation to estimate a new second in-use air filter pressure drop at the second in-use air filter airflow mass flow rate; and

[0058] A second quadratic equation is generated to fit the new second in-use air filter pressure drop and the second in-use air filter airflow mass flow rate to the final in-use air filter relationship.

[0059] Option 8. The method according to Option 7, wherein establishing the rough in-use air filter relationship and the final in-use air filter relationship comprises:

[0060] collecting a plurality of data pairs to refine the relationship between air filter pressure drop and airflow mass flow rate during use;

[0061] organizing the collected plurality of data pairs into a predetermined number of bins;

[0062] averaging the data pairs in each corresponding bin; and

[0063] Each of the first quadratic equation of the rough in-use air filter relationship and the second quadratic equation of the final in-use air filter relationship is generated using the average data pairs of the in-use air filter.

[0064] Scheme 9. The method according to Scheme 8, wherein:

[0065] Generating the second quadratic equation includes determining polynomial coefficients of the second quadratic equation; and

[0066] Determining the maximum air filter pressure drop of the in-use air filter includes using the end-in-use air filter relationship.

[0067] Embodiment 10. The method of embodiment 1, further comprising setting a sensor signal when the calculated pressure drop difference is equal to or greater than a predetermined value.

[0068] A self-calibrating air filter life monitoring system for an internal combustion engine (ICE) comprising:

[0069] an air intake system having an air filter in fluid communication with the ICE; and

[0070] an electronic controller configured to determine a remaining useful life of the air filter and programmed to:

[0071] acquiring a first clean air filter data set defined by a first clean air filter pressure, a first clean air filter airflow mass flow rate, and a first clean air filter temperature at a low ICE speed;

[0072] acquiring a second clean air filter data set defined by a second clean air filter pressure, a second clean air filter airflow mass flow rate, and a second clean air filter temperature at an elevated ICE speed;

[0073] establishing a relationship between clean air filter pressure drop and airflow mass flow rate using the acquired clean air filter first data set and second data set;

[0074] determining a maximum clean air filter pressure drop across the clean air filter at a predetermined maximum airflow mass flow rate using the clean air filter relationship;

[0075] acquiring a first in-use air filter data set defined by a first in-use air filter pressure, a first in-use air filter airflow mass flow rate, and a first in-use air filter temperature at the low ICE speed;

[0076] acquiring a second in-use air filter data set defined by a second in-use air filter pressure, a second in-use air filter airflow mass flow rate, and a second in-use air filter temperature at the elevated ICE speed;

[0077] Using the acquired first and second data sets of the air filter in use, the relationship between the pressure drop of the air filter in use and the mass flow rate of the air flow is established;

[0078] determining a maximum in-use air filter pressure drop of the in-use air filter at the predetermined maximum airflow mass flow rate using the in-use air filter relationship;

[0079] comparing the maximum air filter pressure drops of the in-use air filter and the clean air filter to calculate a difference in the in-use air filter pressure drop relative to the clean air filter pressure drop at the predetermined maximum airflow mass flow rate; and

[0080] The remaining useful life of the air filter in use corresponding to the calculated pressure drop difference is determined and stored.

[0081] Embodiment 12. The self-calibrating air filter life monitoring system of embodiment 11, wherein the electronic controller is further programmed to:

[0082] determining atmospheric pressure downstream of the clean air filter with the ICE turned off;

[0083] determining a clean air filter pressure at the low ICE speed;

[0084] determining a clean air filter pressure drop via calculating a difference between a determined atmospheric pressure downstream of the clean air filter with the ICE off and a determined clean air filter pressure at the low ICE speed; and

[0085] The clean air filter relationship is also established using a clean air filter pressure drop determined at the first clean air filter airflow mass flow rate.

[0086] Embodiment 13. The self-calibrating air filter life monitoring system of embodiment 12, wherein the electronic controller is programmed to establish the clean air filter relationship in two stages, and the electronic controller is further programmed to:

[0087] establishing, in a first stage, a coarse clean air filter relationship using the acquired clean air filter first and second data sets and the clean air filter pressure drop to estimate the second clean air filter pressure drop at the second clean air filter airflow mass flow rate;

[0088] generating a first quadratic equation to fit the second clean air filter pressure drop and the second clean air filter airflow mass flow rate to the coarse clean air filter relationship;

[0089] establishing in a second stage a final clean air filter relationship using the new first and second air filter data sets and the first quadratic equation to estimate a final second clean air filter pressure drop at a final second clean air filter airflow mass flow rate; and

[0090] A second quadratic equation is generated to fit the final second clean air filter pressure drop and the final second clean air filter airflow mass flow rate to the final clean air filter relationship.

[0091] Embodiment 14. The self-calibrating air filter life monitoring system of embodiment 13, wherein, to establish the coarse air filter relationship and the final clean air filter relationship, the electronic controller is programmed to:

[0092] Collect multiple data pairs to refine the clean air filter pressure drop versus airflow mass flow rate relationship;

[0093] organizing the collected plurality of data pairs into a predetermined number of bins;

[0094] averaging the data pairs in each corresponding bin; and

[0095] Each of the first quadratic equation of the rough clean air filter relationship and the second quadratic equation of the final clean air filter relationship is generated using the average data pair of the clean air filter.

[0096] Embodiment 15. The self-calibrating air filter life monitoring system of embodiment 14, wherein the electronic controller is further programmed to:

[0097] determining polynomial coefficients of the second quadratic equation to generate the second quadratic equation; and

[0098] The final clean air filter relationship is used to determine a maximum air filter pressure drop for the clean air filter.

[0099] Embodiment 16. The self-calibrating air filter life monitoring system of embodiment 11, wherein the electronic controller is further programmed to:

[0100] determining atmospheric pressure downstream of the in-use air filter with the ICE turned off;

[0101] determining an in-use air filter pressure at said low ICE speed;

[0102] determining an in-use air filter pressure drop by calculating a difference between atmospheric pressure downstream of the in-use air filter determined with the ICE off and an in-use air filter pressure determined at the low ICE speed; and

[0103] The in-use air filter relationship is also established using the determined in-use air filter pressure drop at the first in-use air filter airflow mass flow rate.

[0104] Embodiment 17. The self-calibrating air filter life monitoring system of embodiment 16, wherein the electronic controller is programmed to establish the in-use air filter relationship in two stages, and the electronic controller is further programmed to:

[0105] establishing a coarse in-use air filter relationship in a first stage using the acquired first and second in-use air filter data sets and the in-use air filter pressure drop to estimate a second in-use air filter pressure drop at the second in-use air filter airflow mass flow rate;

[0106] generating a first quadratic equation to fit the second in-use air filter pressure drop and the second in-use air filter airflow mass flow rate to the coarse in-use air filter relationship;

[0107] establishing a final in-use air filter relationship in a second stage using the new first and second in-use air filter data sets and the first quadratic equation to estimate a new second in-use air filter pressure drop at the second in-use air filter airflow mass flow rate; and

[0108] A second quadratic equation is generated to fit the new second in-use air filter pressure drop and the second in-use air filter airflow mass flow rate to the final in-use air filter relationship.

[0109] Embodiment 18. The self-calibrating air filter life monitoring system of embodiment 17, wherein, to establish the rough in-use air filter relationship and the final in-use air filter relationship, the electronic controller is programmed to:

[0110] Collect multiple data pairs to refine the relationship between in-use air filter pressure drop and airflow mass flow rate;

[0111] organizing the collected plurality of data pairs into a predetermined number of bins;

[0112] averaging the data pairs in each corresponding bin; and

[0113] Each of the first quadratic equation of the rough in-use air filter relationship and the second quadratic equation of the final in-use air filter relationship is generated using the average data pairs of the in-use air filter.

[0114] Embodiment 19. The self-calibrating air filter life monitoring system of embodiment 18, wherein:

[0115] determining polynomial coefficients of the second quadratic equation to generate the second quadratic equation; and

[0116] The final clean air filter relationship is used to determine a maximum air filter pressure drop for the in-use air filter.

[0117] Embodiment 20. A non-transitory computer-readable medium having stored thereon executable instructions for self-calibration of an internal combustion engine (ICE) air filter life monitoring system, the executable instructions comprising:

[0118] acquiring a first clean air filter data set defined by a first clean air filter pressure, a first clean air filter airflow mass flow rate, and a first clean air filter temperature via conditioning and interrogating corresponding sensors at a low ICE speed;

[0119] acquiring a second clean air filter data set defined by a second clean air filter pressure, a second clean air filter airflow mass flow rate, and a second clean air filter temperature via conditioning and interrogating the respective sensors at an elevated ICE speed;

[0120] establishing, via the electronic controller, a relationship between a clean air filter pressure drop and an airflow mass flow rate using the acquired clean air filter first data set and the acquired second data set;

[0121] determining a maximum clean air filter pressure drop across the clean air filter at a predetermined maximum airflow mass flow rate using a clean air filter relationship;

[0122] acquiring a first in-use air filter data set defined by a first in-use air filter pressure, a first in-use air filter airflow mass flow rate, and a first in-use air filter temperature via conditioning and interrogating respective sensors at the low ICE speed;

[0123] acquiring a second in-use air filter data set defined by a second in-use air filter pressure, a second in-use air filter airflow mass flow rate, and a second in-use air filter temperature via conditioning and interrogating the respective sensors at the elevated ICE speed;

[0124] establishing, via the electronic controller, a relationship between an in-use air filter pressure drop and an airflow mass flow rate using the acquired first and second data sets of the in-use air filter;

[0125] determining a maximum in-use air filter pressure drop of the in-use air filter at the predetermined maximum airflow mass flow rate using the in-use air filter relationship;

[0126] comparing, via the electronic controller, the maximum air filter pressure drops of the clean air filter and the in-use air filter to calculate a difference in the in-use air filter pressure drop relative to the clean air filter pressure drop at the predetermined maximum airflow mass flow rate;

[0127] determining and storing, via the electronic controller, a remaining useful life of the in-use air filter corresponding to the calculated pressure drop differential; and

[0128] When the calculated pressure drop difference is equal to or greater than a predetermined value, the sensor signal is set.

[0129] The above features and advantages and other features and advantages of the present disclosure are readily apparent from the following detailed description of the described embodiment(s) and best mode(s) for carrying out the described invention when taken in conjunction with the accompanying drawings and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0130] Figure 1 is a schematic diagram of a vehicle including an internal combustion engine using an air intake system with an air filter and employing a self-calibrating air filter life monitoring system regulated by an electronic controller in accordance with the present disclosure.

[0131] Figure 2 yes Figure 1 A schematic close-up partial side view of the air intake system and air filter is shown, illustrating the arrangement of pressure, temperature, and airflow mass flow rate sensors in communication with an electronic controller.

[0132] Figure 3 is a graph of pressure drop versus airflow mass flow rate showing a two-stage progression of clean air filter relationships and used air filter relationships via an air filter life monitoring system in accordance with the present disclosure.

[0133] Figure 4 is a graph of pressure drop versus airflow mass flow rate according to the present disclosure, illustrating a comparison of a clean air filter relationship formed and an in-use air filter relationship formed during determination of the remaining useful life of the in-use air filter corresponding to a calculated pressure drop increment.

[0134] Figure 5 Shown Figures 1-4 Illustrated is the self-calibration of an ICE air filter life monitoring system and the method of determining the remaining useful life of an air filter in use. DETAILED DESCRIPTION

[0135] Referring to the drawings, wherein like reference numerals correspond to like or similar parts throughout the several views, Figure 1 A vehicle 10 is shown having an internal combustion engine (ICE) 12. Figure 1 As shown in FIG, the ICE 12 includes an intake system 14 configured to direct airflow 16 from the surrounding environment to the combustion chamber (not shown) of the engine. The intake system 14 includes an air inlet duct 18 in fluid communication with the ICE 12, as shown in FIG. Figure 1 and 2 The intake system 14 also includes an air filter 20, which is typically housed in an air filter housing 22 (e.g. Figure 1 and 2 1 (shown) and upstream of the combustion chamber for removing particulate matter, such as foreign particles and other airborne debris, from the airflow 16. An air inlet duct 18 is configured to direct the airflow 16 from the ambient environment to the combustion chamber, such as via an intake manifold (not shown). The intake manifold, in turn, distributes the airflow 16 to the combustion chamber for mixing with an appropriate amount of fuel and subsequently combusting the resulting fuel-air mixture.

[0136] Typically, an air filter, such as air filter 20, when in its new or clean state, allows incoming air to pass through without a significant pressure difference or pressure drop (ΔP) between the upstream and downstream sides of the air filter. Thus, a clean air filter can remove particulate matter from the air flow without creating a significant restriction in the air duct and clogging the engine's air supply. When the air filter becomes clogged with particulate matter, the pressure drop increases to a point where the restriction begins to adversely affect engine efficiency, and the filter is considered to have reached the end of its useful life and replacement is recommended. The pressure difference across a new and end-of-life air filter can be determined empirically, such as during laboratory testing, within an expected range of airflow mass flow rates for a particular engine. The actual pressure and airflow mass flow rate can be determined or measured via respective sensors located within the respective intake systems and in communication with an electronic data processor.

[0137] Reference Figure 2The vehicle 10 also includes a self-calibrating air filter life monitoring system 24. The air filter life monitoring system 24 includes the air intake system 14, and an airflow mass flow rate sensor 25-1, a pressure sensor 25-2, and an air temperature sensor 25-3 located therein. The air filter life monitoring system 24 also includes an electronic controller 26, which communicates with the airflow mass flow rate sensor 25-1, the pressure sensor 25-2, and the air temperature sensor 25-3. The electronic controller 26 is in operative communication with the ICE 12. The electronic controller 26 can be a central processing unit (CPU) configured to regulate various functions on the vehicle 10 or a dedicated electronic control unit (ECU) having a microprocessor. Among the various communication, processing, and management functions, the electronic controller 26 is configured (i.e., constructed and programmed) to determine the remaining useful life of the air filter 20.

[0138] In order to support the determination of the remaining useful life of the air filter 20, the electronic controller 26 particularly includes a processor and a tangible non-transitory memory, which includes instructions programmed therein for processing data signals and executing commands. The memory can be a suitable recordable medium that participates in providing computer-readable data or processing instructions. Such recordable media can take many forms, including but not limited to non-volatile media and volatile media. Non-volatile media for the electronic controller 26 can include, for example, optical or magnetic disks and other permanent memories. Volatile media can include, for example, dynamic random access memory (DRAM), which can constitute main memory. The instructions programmed into the electronic controller 26 can be transmitted through one or more transmission media, including coaxial cables, copper wires and optical fibers, including cables containing a system bus connected to the processor of the computer, or transmitted via a wireless connection.

[0139] The memory of the electronic controller 26 may also include a floppy disk, a hard disk, a magnetic tape, another magnetic medium, a CD-ROM, a DVD, another optical medium, etc. The electronic controller 26 may be constructed or equipped with other required computer hardware, such as a high-speed clock, necessary analog-to-digital (A / D) and / or digital-to-analog (D / A) circuits, input / output circuits and devices (I / O), and appropriate signal conditioning and / or buffering circuits. Subsystems and algorithms required or accessible by the electronic controller 26, generally represented by the numeral 28, may be stored in the controller's memory and automatically executed to facilitate operation of the air filter life monitoring system 24. In particular, the subsystems and algorithms 28 may include an inventory mode that is configured to monitor the air intake system 14 and / or interrogate the air intake system at predetermined time intervals, the time intervals being measured via the high-speed clock. Thus, the electronic controller 26 includes a non-transitory computer-readable medium having instructions stored thereon that, when executed by one or more processors, cause a set of functions to be performed as described in detail below.

[0140] The electronic controller 26 can be programmed to adjust the speed of the ICE 12 to obtain data for cleaning and using the air filter, as described in detail below. The electronic controller 26 is specifically programmed to begin determining the remaining useful life of the air filter 20 by acquiring two different sets of data from the intake system: the airflow mass flow rate in g / sec (via airflow mass flow rate sensor 25-1), the corresponding air pressure in kPa (via pressure sensor 25-2), and the air temperature in degrees Celsius (via air temperature sensor 25-3). The electronic controller 26 can be programmed to begin determining the remaining useful life of the air filter 20 once the vehicle 10 has traveled a predetermined distance to ensure that the vehicle is subject to real-world operating conditions. The electronic controller 26 is specifically programmed to acquire the two different sets of data under steady-state conditions of the ICE 12. Generally, various methods and hardware can be used to acquire the air pressure, temperature, and airflow mass flow rate data sets, which can then be used to determine the remaining useful life of the engine air filter.

[0141] The electronic controller 26 specifically includes subsystems and algorithms 28 configured to monitor the functions of the ICE 12 and the vehicle 10, including an engine operating mode state 30 indicating whether the ICE is running or off, an engine idle active state 32 indicating whether the ICE is operating at idle speed, and a catalyst warm-up state 34 indicating whether the exhaust gas emission system catalyst has reached a thermal threshold. The electronic controller 26 also includes an elapsed time counter 36 configured to record the total elapsed time that the vehicle 10 has been in use. The electronic controller 26 also monitors the vehicle's odometer (not shown), which can be displayed on the instrument panel of the vehicle 10 and is configured to record the total distance or mileage of the vehicle since it was first driven.

[0142] Reference Figure 2, the electronic controller 26 may be further programmed to display a message 38 on the vehicle's instrument panel that corresponds to the encoded stored record of the percentage remaining useful life of the in-use air filter 20. Thus, the message 38 is intended to inform the vehicle user or service technician of the percentage remaining useful life of the in-use air filter 20. The electronic controller 26 may also be programmed to set a sensor signal 40 when the calculated pressure drop differential is equal to or greater than a predetermined value 42 (such as within the range of 2.3-2.5 kPa), or when the percentage remaining useful life of the in-use air filter 20 is equal to or less than a predetermined percentage threshold (such as within the range of 0%-5%). Thus, the electronic controller 26 may include a non-transitory computer-readable medium having executable instructions stored thereon and specifically configured to set the sensor signal 40. In either case, the sensor signal 40 is intended to indicate that the air filter 20 has become clogged with particulate matter. In other words, the sensor signal 40 is intended to alert the vehicle user and / or service technician that the air filter 20 has reached the end of its useful life and recommends replacing the air filter.

[0143] Figure 3 and Figure 4 A graph showing the relationship between the pressure drop (from atmospheric pressure to the pressure value detected by the pressure sensor 25-2) and the airflow mass flow rate detected by the airflow mass flow rate sensor 25-1 is shown, the graph of the relationship being corrected to a reference ambient pressure of 100 kPa and a reference temperature of 20°C. Figure 3 and Figure 4 The development and establishment of a cleaning and in-use air filter life relationship is shown as the relationship between pressure drop and airflow mass flow rate, as reflected in the corresponding curves in two different stages (Stage 1 and Stage 2), which will be described in more detail below. Figure 3 A clean air filter self-calibration relationship or curve 44 is shown showing the relationship between pressure drop and airflow mass flow rate for a given ICE 12 and vehicle 10 configuration. The establishment of the clean air filter self-calibration relationship or curve 44 may begin at stage 1, which includes establishing an initial rough estimate of the clean air filter self-calibration relationship or curve 46, which is Figure 3 4. This is shown as a region bounded by two curves 46A and 46B.

[0144] An initial rough estimate of the clean air filter self-calibration relationship or curve 46 uses air filter pressure drop data from a warm ICE 12 operating at a low engine speed, such as idle, and a first clean air filter data set for operating conditions 48 approaching the target low engine speed condition. The operating conditions 48 are specifically established to allow an initial rough estimate of the clean air filter self-calibration relationship or curve 46 to be established without directly sensing the atmospheric pressure so that the atmospheric pressure term can be eliminated in subsequent calculations. The operating conditions 48 constraints are imposed on the data set used to construct the initial rough estimate of the clean air filter self-calibration relationship or curve 46 because one data set will represent operating conditions close to the warm ICE 12 low engine speed (e.g., engine idle) condition, as determined by Figure 3 The relatively small data range shown in FIG is represented herein as Stage 1. Subsequently, an initial rough estimate of the clean air filter self-calibration relationship or curve 46 can be used in conjunction with M having low engine speed operating conditions beyond the warm ICE 12. 1C The atmospheric pressure is estimated from a dataset of items, such as Figure 3 The relatively large range shown in is defined as stage 2. 1C The larger range of φ increases the availability of data having larger airflow mass flow rate values, which in turn can be used to improve the accuracy of the estimate of the clean air filter self-calibration relationship or curve 44 .

[0145] Once the vehicle's set odometer threshold 50 is met, the air filter life monitoring system 24 may begin to establish Figure 3 The clean air filter self-calibration relationship or curve 44 is shown. The air filter life monitoring system 24 sets this threshold 50 to increase the likelihood that the vehicle 10 will be in the hands of the customer during the initial calibration period rather than in the pre-delivery phase. For example, the threshold 50 may be set to 100 km to ensure that the vehicle is subjected to real-world operating conditions. Before the set odometer threshold 50 is reached, the air filter life monitoring system 24 will report a message 38 indicating, under certain circumstances, 100% remaining useful life of the air filter 20 in use.

[0146] exist Figure 3 In stage 1 shown, the pressure drop from atmospheric pressure to the value detected by pressure sensor 25-2 under the warm ICE 12 low speed condition is determined. The warm ICE 12 low speed condition can be defined by the engine operating mode state 30 being set to run, and each of the engine idle active state 32 and the catalyst warm-up state 34 being set to true. When the electronic controller 26 determines that the warm ICE 12 low engine speed condition is met, the airflow mass flow rate (detected by air mass flow rate sensor 25-1), the corresponding air pressure (detected via pressure sensor 25-2) and air temperature (detected via air temperature sensor 25-3) is recorded in the controller memory. The air filter life monitoring system 24 then monitors the engine operating mode state 30 for a transition or change. If the engine operating mode state 30 transitions from ON to OFF within a calibrated elapsed time threshold detected by the counter 36, the electronic controller 26 records the air pressure (detected via pressure sensor 25-2) and air temperature (detected via the air temperature sensor 25-3).

[0147] The air pressure data with the engine off corresponds to the atmospheric pressure at the time of recording. The pressure drop at idle (i.e., at the necessary low engine speed conditions) or Specifically defined as follows:

[0148]

[0149] in,

[0150] The calculated Corrected to a reference ambient pressure of 100 kPa and a reference temperature of 20°C:

[0151]

[0152] The electronic controller 26 repeats the above steps N times to determine the pressure drop from atmospheric pressure to the pressure value detected by the pressure sensor 25-2 at the low speed of the warm ICE 12. The number N is a pre-set empirical calibration value that allows the average value of the pressure drop and the airflow mass flow rate to be determined by the following equation:

[0153]

[0154] like Figure 3 As can be seen, each of the pressure drop versus airflow mass flow rate relationships or curves 44 and 46 will intersect the origin, where zero airflow mass flow rate occurs at zero pressure drop. Figure 3 Also shown is the corrected warm ICE 12 low speed (eg, idle) condition. 52.

[0155] A first initial rough clean air filter self-calibration relationship or curve 46 is established using the data set, wherein the curve for operating condition 48 ( Figure 3 The first clean air filter data set (shown in Within the predetermined time frame t1 of determining the first clean air filter data set, a second clean air filter data set is acquired for operating condition 56 at an elevated ICE 12 speed (ie, substantially above idle). The predetermined time frame t1 is intended to provide a sufficient amount of time to allow for significant changes in the airflow mass flow rate and airflow pressure, but without significant changes in ambient conditions. In other words, the predetermined time frame t1 can be selected to minimize errors that might otherwise be caused by changes in atmospheric pressure due to changes in weather conditions, geographic altitude, or other factors. For example, the predetermined time frame t1 can be in the range of 2-8 seconds to facilitate capturing lower airflow mass flow rates M. 1C and higher air mass flow rate M 2C The maximum interval between.

[0156] When the first clean air filter set for operating condition 48 is obtained When M 1C exist Figure 3 The narrow band of stage 1 shown is approximately , the pressure drop is approximated after correction to a reference ambient pressure of 100 kPa and a reference temperature of 20°C as:

[0157]

[0158] In addition, after correction to a reference ambient pressure of 100 kPa and a reference temperature of 20°C, for operating condition 56, the second clean air filter data set The pressure drop at is given by:

[0159]

[0160] Combining equations (6) and (7) to eliminate P atm term (as above), we get:

[0161]

[0162] Figure 3 shows the operating conditions for 56 The electronic controller 26 is programmed to repeat the process of collecting a data set having one data set with a relatively low airflow mass flow rate under the warm ICE 12 low speed condition until a sufficient number of data pairs for representative operating conditions 56 are collected, wherein M 1C In the narrow band of stage 1, it is approximately Thus, the plurality of data pairs collected for the operating conditions 56 are organized and stored in a predetermined number of discrete bins. The electronic controller 26 can then store the data pairs in the bins by airflow mass rate, with each discrete bin storing data pairs over a predetermined range of airflow mass rate values.

[0163] The electronic controller 26 can be programmed to collect a minimum amount of The electronic controller 26 may additionally be programmed to continuously monitor the data in each corresponding bin as follows: Average the data pairs:

[0164]

[0165] In the above relations (9) and (10), factor i represents the i-th bin, and factor j represents the j-th data pair in the i-th bin. The number of bins is not limited, i.e., as many or as few bins as needed can be used to map the desired number of discrete Once the bin has enough data, an initial quadratic curve can be fitted to the data to establish an initial rough clean air filter self-calibration relationship or curve 46 with a zero intercept as follows:

[0166]

[0167] The coefficients c1 and c2 in equation (11) represent the regression best fit for the clean air filter data collected during Phase 1.

[0168] In stage 2, the electronic controller 26 may use equation (11), the clean air filter self-calibration relationship or an initial rough estimate of the curve 46 in conjunction with a first clean air filter data set for the operating condition 48 To estimate the atmospheric pressure, where M 1C Items are within the larger stage 2, e.g. Figure 3 The electronic controller 26 may acquire a second clean air filter data set for the operating condition 56 at the elevated ICE 12 speed within a predetermined time frame t1 of determining the first clean air filter data set. The electronic controller 26 may determine a second clean air filter data set for the operating condition 56 The pressure drop at , including correction to a reference ambient pressure of 100 kPa and a reference temperature of 20°C, is as follows:

[0169]

[0170] Figure 3 The data for operating condition 56 is shown. The electronic controller 26 may repeat the process of collecting the data set in stage 2, grouping and averaging the data in discrete predetermined bins, as described above with respect to stage 1. The electronic controller 26 may then establish a final clean air filter relationship or curve 44 based on a quadratic regression fit of the data from stage 2 according to the following equation:

[0171]

[0172] The coefficients d1 and d2 in equation (13) represent the regression best fit of the clean air filter data in phase 2. The electronic controller 26 can then calculate the maximum airflow mass flow rate M at the preset maximum airflow mass flow rate as follows max Extrapolated maximum clean air filter pressure drop under 58:

[0173]

[0174] For example, for a particular ICE 12 operating at peak performance (eg, 200 gm / sec), a preset maximum airflow mass flow rate may be established empirically. M max .

[0175] After establishing the clean air filter relationship or curve 44, once the air filter 20 is in use, the electronic controller 26 may initiate monitoring of the target air filter and the in-use air filter relationship or curve 60 ( Figure 4 Monitoring of the in-use air filter 20 and construction of the in-use air filter relationship or curve 60 may begin in the same manner as construction of the clean air filter relationship or curve 44. In other words, the in-use air filter relationship or curve 60 may be constructed using a two-stage process, beginning with determining the pressure drop of the warm ICE 12 at low engine speeds, such as idle, followed by a Stage 1 initial rough in-use air filter curve determination.

[0176] Similar to the cleaning curve development, when the corresponding bin has sufficient data, an initial quadratic curve can be fitted to the data To establish an initial rough in-use air filter self-calibration curve with zero intercept as follows (similar to the clean filter self-calibration relationship or curve 46):

[0177]

[0178] The coefficients e1 and e2 in equation (15) represent the best fit of the regression of the in-use air filter data collected during phase 1. The final in-use air filter relationship or curve during phase 2 is then The determination of 60 is given by the following formula:

[0179]

[0180] The coefficients f1 and f2 in equation (16) represent the best fit of the regression of the air filter data during the phase 2 use. The electronic controller 26 can also calculate the maximum airflow mass flow rate M as follows max Extrapolated pressure drop of the air filter in use 62:

[0181]

[0182] refer to Figure 4 , the electronic controller 26 is further programmed to 58. 62 and Figure 2 As shown in M max The predetermined pressure drop limit value at 64 for comparison. 64 is intended to indicate that the air filter 20 has become clogged with particulate matter and is at the end of its useful life. 64 can be set to 2.5 kPa. Figure 4 Shows the maximum airflow mass flow rate M max The pressure drop at the end of the air filter life is 66, which is equal to 58 Sum The electronic controller 26 calculates and stores the proportion or percentage of the remaining useful life (RULISAF) of the air filters in use as follows:

[0183]

[0184] In other words, the electronic controller 26 may be programmed to determine the remaining useful life of the in-use air filter 20 as a percentage of the maximum life of the clean air filter based on the calculated ΔP.

[0185] Figure 5 A method 100 for self-calibration of an air filter life monitoring system 24 for an internal combustion engine (ICE) is shown and will be referred to below. Figures 1-4 According to this method, the electronic controller 26 can be programmed to adjust the speed of the ICE 12 to obtain relevant clean and in-use air filter data sets, as shown in FIG. Figures 1-4As described above and described in further detail below, method 100 begins at block 102. The method may begin determining the remaining useful life of the air filter 20 by verifying, via the electronic controller 26 in communication with the vehicle odometer, that a predetermined elapsed distance threshold 50 has been met. Additionally, in block 102, the method may include determining the airflow mass flow rate, air pressure, and air temperature via the electronic controller 26 in communication with the corresponding airflow mass flow rate sensor 25-1, pressure sensor 25-2, and air temperature sensor 25-3.

[0186] After frame 102, the method proceeds to frame 104 to begin construction of the clean air filter relationship or curve 44. In frame 104, the method includes obtaining a first clean air filter pressure (P 1C ), first clean air filter airflow mass flow rate (M 1C ) and the first clean air filter temperature (T 1C ) is defined by a first clean air filter data set. The acquisition of the first clean air filter data set is performed via the electronic controller 26 regulating and interrogating the pressure sensor 25-2, the airflow mass flow rate sensor 25-1, and the air temperature sensor 25-3. From box 104, the method proceeds to box 106, wherein the method includes, via the electronic controller 26 regulating and interrogating the corresponding pressure, airflow mass flow rate, and air temperature sensors, acquiring, at elevated ICE speed, a second clean air filter pressure (P 2C ), second clean air filter airflow mass flow rate (M 2C ) and the second clean air filter temperature (T 2C ). After frame 106, the method proceeds to frame 108. In frame 108, the method includes using the acquired clean air filter first and second data sets via the electronic controller 26 to establish a relationship between clean air filter pressure drop and airflow mass flow rate.

[0187] In frame 108, the method may further include determining, via the electronic controller 26, the atmospheric pressure downstream of the clean air filter with the ICE 12 off and determining the clean air filter pressure at low ICE 12 speeds. In frame 108, the method may further include determining the clean air filter pressure drop. Figures 1-4 As described, the clean air filter pressure drop value may be corrected to a reference ambient pressure of 100 kPa and a reference temperature of 20° C. Determining the clean air filter pressure drop may specifically include determining an average clean air filter pressure drop value by calculating an average difference between a determined atmospheric pressure downstream of the clean air filter with the ICE 12 turned off and a determined clean air filter pressure at low ICE speeds. , as described above with respect to mathematical equations (1) to (5). In addition, in block 108, establishing a clean air filter relationship may include: using the first clean air filter airflow mass flow rate (M 1C ) determined clean air filter pressure drop under .

[0188] As mentioned above about Figures 1-4 As described above, establishing the clean air filter relationship can be completed in two stages, namely, stage 1 and stage 2. In particular, establishing the clean air filter relationship can include: using the acquired clean air filter first and second data sets and the clean air filter pressure drop The rough clean air filter relationship in stage 1 is established to estimate the mass flow rate (M) of the airflow at the second clean air filter. 2C ) corrected to a reference ambient pressure of 100 kPa and a reference temperature of 20°C for the second clean air filter Establishing the clean air filter relationship may include generating a first quadratic equation to determine the second clean air filter pressure drop and the second clean air filter airflow mass flow rate (M 2C ) is fitted to the rough clean air filter relationship. Establishing the clean air filter relationship may also include: establishing a final clean air filter relationship in stage 2 using the new first and second clean air filter data sets and the first quadratic equation to estimate the final second clean air filter airflow mass flow rate (M 2C ) corrected to a reference ambient pressure of 100 kPa and a reference temperature of 20°C. Additionally, establishing the clean air filter relationship may include generating a second quadratic equation to obtain a new second clean air filter pressure drop and the second clean air filter airflow mass flow rate (M 2C ) is fitted with the final clean air filter relationship.

[0189] As mentioned above about Figures 1-4 As described above, establishing a rough and final clean air filter relationship may include: collecting multiple data pairs To further improve the estimated clean air filter pressure drop and airflow mass flow rate relationship. The method may also include collecting a plurality of data pairs Organized in a predetermined number of bins and averaged in each corresponding bin data pairs. And further, the method may include using the average of the clean air filters for each i-th bin based on equations (9) and (10) data pairs to generate each of the first quadratic equation (11) for the rough clean air filter relationship and the second quadratic equation (13) for the final clean air filter relationship. According to this method, as cited above in equation (12), the second clean air filter data set for operating condition 56 is determined The pressure drop at may include a reference ambient pressure corrected to 100 kPa and a reference temperature of 20°C. Figures 1-4 The generating of the second quadratic equation may include determining polynomial coefficients c1 and c2 of the second quadratic equation (11), and determining a maximum clean air filter pressure drop of the clean air filter. Includes use of final clean air filter ties (13).

[0190] After frame 108, the method proceeds to frame 110. In frame 110, the method includes determining via the electronic controller 26 using the final clean air filter relationship (13) that the maximum airflow mass flow rate (M) is the maximum airflow mass flow rate. max ) Maximum clean air filter pressure drop of the clean air filter under Maximum clean air filter pressure drop The determination above about Figures 1-4 is described and represented by the mathematical relationship (14). After frame 110, i.e., after the clean air filter relationship or curve 44 is established, and once the air filter 20 has been placed in service, the method proceeds to frame 112 to begin monitoring the in-service air filter. From frame 112, the method employs the electronic controller 26 to construct the in-service air filter relationship or curve 60 in a configuration similar to that of the clean air filter relationship or curve 44. Frame 112 specifically includes obtaining, via the electronic controller 26, the first in-service air filter pressure at low ICE speeds. , Mass flow of air filter in first use and the first air filter temperature in use After frame 112, the method proceeds to frame 114. In frame 114, the method includes obtaining, via the electronic controller 26, the second in-use air filter pressure at an elevated ICE speed. , Second air filter airflow mass flow rate in use and the second air filter temperature in use As with the clean air filter dataset, the first and second in-use air filter datasets are obtained by adjusting and querying the corresponding pressure sensor 25-2, airflow mass flow rate sensor 25-1, and air temperature sensor 25-3 via the electronic controller 26.

[0191] After frame 114, the method proceeds to frame 116. In frame 116, the method includes using the first and second data sets of the acquired in-use air filter to establish a relationship between the in-use air filter pressure drop and the airflow mass flow rate via the electronic controller 26. In frame 116, the method may also include determining, via the electronic controller 26, the atmospheric pressure downstream of the in-use air filter when the ICE 12 is turned off. Also in frame 116, the method may also include determining, via the electronic controller 26, the in-use air filter pressure at low ICE speeds, such as idle speed. In addition, in frame 116, the method may include determining, via the electronic controller 26, the in-use air filter pressure drop. As described above with respect to the determination of the clean air filter pressure drop value, the air filter pressure drop value may be corrected to a standard temperature and pressure. Determining the in-use air filter pressure drop may specifically include determining an average air filter pressure drop value by calculating the average difference between the determined atmospheric pressure downstream of the in-use air filter when the ICE 12 is turned off and the determined in-use air filter pressure at low ICE speeds. , similar to mathematical equations (1) to (5). In addition, in block 116, establishing the in-use air filter relationship may include: using the first in-use air filter airflow mass flow rate The pressure drop of the air filter in use is determined under .

[0192] Similar developments as above regarding clean air filter relationships Figures 1-4 As described above, in block 116, the in-use air filter relationship may be completed in two corresponding stages (stage 1 and stage 2). Specifically, establishing the in-use air filter relationship may include: using the acquired in-use air filter first and second data sets and the in-use air filter pressure drop To establish a rough in-use air filter relationship in stage 1 to estimate the second in-use air filter airflow mass flow rate Second in-use air filter pressure drop corrected to a reference ambient pressure of 100 kPa and a reference temperature of 20°C In block 116, the method may further include generating a first quadratic equation to convert the second in-use air filter pressure drop and the second air filter airflow mass flow rate in use Fitting the rough in-use air filter relationship. Additionally, in block 116, the method may include using the new first and second in-use air filter data sets and the first quadratic equation to establish a final in-use air filter relationship in stage 2 to estimate the second in-use air filter airflow mass flow rate Pressure drop of a new second-in-use air filter calibrated to a reference ambient pressure of 100 kPa and a reference temperature of 20°C Additionally, in block 116, the method may include generating a second quadratic equation to calculate the new second in-use air filter pressure drop and the second air filter airflow mass flow rate in use Fitting the relationship with the air filter in the final use.

[0193] Establishing the rough and end-use air filter relationship in block 116 may include: collecting multiple data pairs To further improve the estimated in-use air filter pressure drop and airflow mass flow rate relationship. In addition, establishing the rough and final in-use air filter relationship may include organizing the collected multiple data pairs in a predetermined number of bins. , and average the data pairs in each corresponding bin Furthermore, similar to the corresponding development of the clean air filter relationship, establishing the rough and final in-use air filter relationship may include: using the average data of each i-th bin of the in-use air filter Then, we can use the aforementioned average data to to generate each of a first quadratic equation (15) for a rough in-use air filter relationship and a second quadratic equation (16) for a final in-use air filter relationship.

[0194] Additionally, according to the method, in block 116, generating the second quadratic equation may include determining polynomial coefficients of the second quadratic equation. Additionally, determining the maximum in-use air filter pressure drop of the in-use air filter The use of the generated final in-use air filter relationship may be included. As described above, the previous description of the establishment of the in-use air filter relationship is similar to that described in block 108 and with respect to Figures 1-4 After frame 116, the method proceeds to frame 118. In frame 118, the method includes determining, via the electronic controller 26, the maximum airflow mass flow rate (M) of the in-use air filter using the in-use air filter relationship. max ) Maximum in-use air filter pressure drop .

[0195] After frame 118 , the method proceeds to frame 120 , where the method includes setting the maximum in-use air filter pressure drop via the electronic controller 26 to with maximum clean air filter pressure drop Compare to calculate the preset maximum airflow mass flow rate (M max) compared to the clean air filter pressure drop. From frame 120, the method proceeds to frame 122, where the method includes determining and storing, via the electronic controller 26, a percentage remaining useful life (RULISAF) of the in-use air filter corresponding to the calculated pressure drop ΔP difference according to equation (18). After frame 122, the method may proceed to frame 124. In frame 124, the method also includes setting a sensor signal, such as displaying, via the electronic controller 26, a message 38 corresponding to a coded stored record of the remaining useful life of the air filter 20 in the vehicle 10.

[0196] After frame 122 or frame 124, the method may proceed to frame 126. In frame 126, the method includes setting the sensor signal 40 via the electronic controller 26 when the calculated pressure drop ΔP difference is equal to or greater than a predetermined value 42, which may be in the range of 2.3-2.5 kPa. Alternatively, in frame 126, the method may include setting the sensor signal 40 when the %RULISAF determined in equation (18) is equal to or less than a preset RULISAF value (e.g., in the range of 0%-5%) programmed into the electronic controller 26. Additionally, the electronic controller 26 may be programmed to adjust the operation of the ICE 12, such as the torque output of the engine or its maximum allowable speed, in response to the calculated pressure drop ΔP difference being equal to or greater than the predetermined value 42.

[0197] Timely replacement of a clogged air filter is an important factor in maintaining efficient operation of the ICE 12. Thus, as contemplated, the method 100 enables self-calibrated continuous monitoring of the ICE air filter 20 to determine the percentage remaining useful life of the filter as it progresses from a new / clean state to becoming clogged with particulate matter. Figures 1-4 As described, each of the clean air filter relationship or curve 44 and the in-use air filter relationship or curve 60 can be generated in two stages, including generating respective rough and final curves by curve fitting and calculating respective polynomial coefficients. The two-stage generation of the clean and in-use air filter curves is intended to facilitate improved accuracy in determining the remaining useful life of the air filter. In addition, the method 100 enables reporting of the determined useful life of the air filter to the operator or service technician of the host vehicle 10 to enable timely replacement of the air filter 20. Therefore, after frame 122 or 124, the method can loop back to frame 112 to continue monitoring the air filter 20 via the ICE 12 air filter life monitoring system 24. Alternatively, the method can end in frame 128, for example to verify replacement of the air filter 20 at the end of its useful life.

[0198] In summary, the self-calibrating air filter life monitoring system 24 and method 100 provide an efficient determination of the remaining useful life of an air filter and when the filter should be replaced based on actual air filter data. Furthermore, the system 24 and method 100 facilitate determining the remaining useful life of an air filter without requiring expensive calibration testing for each different vehicle-engine combination.

[0199] The detailed description and the accompanying drawings or figures are supportive and descriptive of the present disclosure, but the scope of the present disclosure is limited only by the claims. Although some best modes and other embodiments for carrying out the claimed disclosure have been described in detail, there are various alternative designs and embodiments for practicing the disclosure defined in the appended claims. In addition, the embodiments shown in the drawings or the characteristics of the various embodiments mentioned in this specification are not necessarily to be understood as embodiments that are independent of each other. On the contrary, each feature described in one of the examples of the embodiments can be combined with one or more other desired features from other embodiments to obtain other embodiments that are not described in words or by reference to the drawings. Therefore, such other embodiments fall within the framework of the scope of the appended claims.

Claims

1. A method for self-calibration of an internal combustion engine air filter life monitoring system having an electronic controller, the method comprising: acquiring a first clean air filter data set defined by a first clean air filter pressure, a first clean air filter airflow mass flow rate, and a first clean air filter temperature via conditioning and interrogating corresponding sensors at a low internal combustion engine speed; acquiring a second clean air filter data set defined by a second clean air filter pressure, a second clean air filter airflow mass flow rate, and a second clean air filter temperature via adjusting and interrogating the respective sensors at an elevated internal combustion engine speed; establishing, via the electronic controller, a relationship between a clean air filter pressure drop and an airflow mass flow rate using the acquired clean air filter first data set and the acquired second data set; determining a maximum clean air filter pressure drop of the clean air filter at a preset maximum airflow mass flow rate using a relationship between clean air filter pressure drop and airflow mass flow rate; acquiring a first in-use air filter data set defined by a first in-use air filter pressure, a first in-use air filter airflow mass flow rate, and a first in-use air filter temperature via conditioning and interrogating the respective sensors at the low internal combustion engine speed; acquiring a second in-use air filter data set defined by a second in-use air filter pressure, a second in-use air filter airflow mass flow rate, and a second in-use air filter temperature via conditioning and interrogating the respective sensors at the elevated internal combustion engine speed; establishing, via the electronic controller, a relationship between an in-use air filter pressure drop and an airflow mass flow rate using the acquired first and second data sets of the in-use air filter; Determining the maximum in-use air filter pressure drop of the in-use air filter at the preset maximum air flow rate by using the relationship between the in-use air filter pressure drop and the air flow mass flow rate; comparing, via the electronic controller, the maximum air filter pressure drops of the clean air filter and the in-use air filter to calculate a difference between the maximum in-use air filter pressure drop and the maximum clean air filter pressure drop at the predetermined maximum airflow mass flow rate; as well as The remaining useful life of the in-use air filter corresponding to the calculated pressure drop difference is determined and stored via the electronic controller.

2. The method according to claim 1, further comprising: determining atmospheric pressure downstream of the clean air filter with the internal combustion engine off; determining a clean air filter pressure at the low internal combustion engine speed; as well as determining a clean air filter pressure drop by calculating a difference between a determined atmospheric pressure downstream of the clean air filter with the internal combustion engine off and a determined clean air filter pressure at the low internal combustion engine speed; Wherein establishing the relationship between the clean air filter pressure drop and the airflow mass flow rate further comprises using the clean air filter pressure drop determined at the first clean air filter airflow mass flow rate.

3. The method of claim 2, wherein establishing the relationship between the clean air filter pressure drop and the airflow mass flow rate is done in two stages and comprises: In a first stage, a relationship is established between a coarse clean air filter pressure drop and an airflow mass flow rate using the acquired first and second clean air filter data sets and the clean air filter pressure drop to estimate a second clean air filter pressure drop at the second clean air filter airflow mass flow rate; generating a first quadratic equation to fit the second clean air filter pressure drop and the second clean air filter airflow mass flow rate to the coarse clean air filter pressure drop to airflow mass flow rate relationship; in a second stage, relating a final clean air filter pressure drop to airflow mass flow rate using the new first and second clean air filter data sets and the first quadratic equation to estimate a final second clean air filter pressure drop at a final second clean air filter airflow mass flow rate; as well as A second quadratic equation is generated to fit the final second clean air filter pressure drop and the final second clean air filter airflow mass flow rate to the final clean air filter pressure drop to airflow mass flow rate relationship.

4. The method according to claim 3, wherein: Establishing the relationship between the rough clean air filter pressure drop and the airflow mass flow rate and the relationship between the final clean air filter pressure drop and the airflow mass flow rate includes: Collect multiple data pairs to refine the clean air filter pressure drop versus airflow mass flow rate relationship; organizing the collected plurality of data pairs into a predetermined number of bins; averaging the data pairs in each corresponding bin; and Each of the first quadratic equation relating the rough clean air filter pressure drop to airflow mass flow rate and the second quadratic equation relating the final clean air filter pressure drop to airflow mass flow rate is generated using the averaged clean air filter data pairs.

5. The method according to claim 4, wherein: Generating the second quadratic equation includes determining polynomial coefficients of the second quadratic equation; as well as Determining a maximum clean air filter pressure drop of the clean air filter includes using a relationship between final clean air filter pressure drop and airflow mass flow rate.

6. The method according to claim 1, further comprising: determining atmospheric pressure downstream of the in-use air filter with the internal combustion engine shut off; determining an in-use air filter pressure at said low internal combustion engine speed; as well as determining an in-use air filter pressure drop by calculating a difference between an atmospheric pressure downstream of the in-use air filter determined with the engine off and an in-use air filter pressure determined at the low engine speed; Wherein, establishing the relationship between the in-use air filter pressure drop and the airflow mass flow rate further comprises using the in-use air filter pressure drop determined at the first in-use air filter airflow mass flow rate.

7. The method of claim 6, wherein establishing the relationship between the in-use air filter pressure drop and the airflow mass flow rate is done in two stages and comprises: In a first stage, using the acquired first and second data sets of in-use air filter and the in-use air filter pressure drop, a rough in-use air filter pressure drop versus airflow mass flow rate is established to estimate a second in-use air filter pressure drop at the second in-use air filter airflow mass flow rate; generating a first quadratic equation to fit the second in-use air filter pressure drop and the second in-use air filter airflow mass flow rate to the rough in-use air filter pressure drop to airflow mass flow rate relationship; in a second stage, relating the final in-use air filter pressure drop to the airflow mass flow rate using the new first and second in-use air filter data sets and the first quadratic equation to estimate a new second in-use air filter pressure drop at the second in-use air filter airflow mass flow rate; as well as A second quadratic equation is generated to fit the new second in-use air filter pressure drop and the second in-use air filter airflow mass flow rate to the final in-use air filter pressure drop to airflow mass flow rate relationship.

8. The method of claim 7, wherein establishing the relationship between the rough-in-use air filter pressure drop and the airflow mass flow rate and the final-in-use air filter pressure drop and the airflow mass flow rate comprises: collecting a plurality of data pairs to refine the relationship between air filter pressure drop and airflow mass flow rate during use; organizing the collected plurality of data pairs into a predetermined number of bins; Average the data pairs in each corresponding bin; as well as Each of the first quadratic equation relating the rough in-use air filter pressure drop to airflow mass flow rate and the second quadratic equation relating the final in-use air filter pressure drop to airflow mass flow rate is generated using the averaged data pairs of the in-use air filter.

9. The method according to claim 8, wherein: Generating the second quadratic equation includes determining polynomial coefficients of the second quadratic equation; and Determining the maximum in-use air filter pressure drop of the in-use air filter includes using a relationship between the final in-use air filter pressure drop and the mass flow rate of the airflow.

10. The method of claim 1, further comprising setting a sensor signal when the calculated pressure drop difference is equal to or greater than a predetermined value.

11. A self-calibrating air filter life monitoring system for an internal combustion engine, comprising: an air intake system having an air filter in fluid communication with the internal combustion engine; as well as an electronic controller configured to determine a remaining useful life of the air filter and programmed to: acquire a first clean air filter data set defined by a first clean air filter pressure, a first clean air filter airflow mass flow rate, and a first clean air filter temperature at a low internal combustion engine speed; acquiring a second clean air filter data set defined by a second clean air filter pressure, a second clean air filter airflow mass flow rate, and a second clean air filter temperature at an elevated internal combustion engine speed; establishing a relationship between clean air filter pressure drop and airflow mass flow rate using the acquired clean air filter first data set and second data set; determining a maximum clean air filter pressure drop of the clean air filter at a preset maximum airflow mass flow rate using the relationship between the clean air filter pressure drop and the airflow mass flow rate; acquiring a first in-use air filter data set defined by a first in-use air filter pressure, a first in-use air filter airflow mass flow rate, and a first in-use air filter temperature at the low internal combustion engine speed; acquiring a second in-use air filter data set defined by a second in-use air filter pressure, a second in-use air filter airflow mass flow rate, and a second in-use air filter temperature at the elevated internal combustion engine speed; Using the acquired first and second data sets of the air filter in use, the relationship between the pressure drop of the air filter in use and the mass flow rate of the air flow is established; Determining a maximum in-use air filter pressure drop of the in-use air filter at the preset maximum air flow rate using the relationship between the in-use air filter pressure drop and the air flow mass flow rate; comparing the maximum air filter pressure drops of the in-use air filter and the clean air filter to calculate a difference between the maximum in-use air filter pressure drop and the maximum clean air filter pressure drop at the predetermined maximum airflow mass flow rate; as well as The remaining useful life of the air filter in use corresponding to the calculated pressure drop difference is determined and stored.

12. The self-calibrating air filter life monitoring system of claim 11 , wherein the electronic controller is further programmed to: determining atmospheric pressure downstream of the clean air filter with the internal combustion engine off; determining a clean air filter pressure at the low internal combustion engine speed; determining a clean air filter pressure drop by calculating a difference between a determined atmospheric pressure downstream of the clean air filter with the internal combustion engine off and a determined clean air filter pressure at the low internal combustion engine speed; as well as The clean air filter pressure drop determined at the first clean air filter airflow mass flow rate is also used to relate the clean air filter pressure drop to airflow mass flow rate.

13. The self-calibrating air filter life monitoring system of claim 12 , wherein the electronic controller is programmed to relate the clean air filter pressure drop to airflow mass flow rate in two stages, and the electronic controller is further programmed to: In a first stage, a relationship is established between a coarse clean air filter pressure drop and an airflow mass flow rate using the acquired first and second clean air filter data sets and the clean air filter pressure drop to estimate a second clean air filter pressure drop at the second clean air filter airflow mass flow rate; generating a first quadratic equation to fit the second clean air filter pressure drop and the second clean air filter airflow mass flow rate to the coarse clean air filter pressure drop to airflow mass flow rate relationship; in a second stage, relating a final clean air filter pressure drop to airflow mass flow rate using the new first and second clean air filter data sets and the first quadratic equation to estimate a final second clean air filter pressure drop at a final second clean air filter airflow mass flow rate; as well as A second quadratic equation is generated to fit the final second clean air filter pressure drop and the final second clean air filter airflow mass flow rate to the final clean air filter pressure drop to airflow mass flow rate relationship.

14. The self-calibrating air filter life monitoring system of claim 13, wherein: To establish the relationship between the coarse air filter pressure drop and the airflow mass flow rate and the final clean air filter pressure drop and the airflow mass flow rate, the electronic controller is programmed to: Collect multiple data pairs to refine the clean air filter pressure drop versus airflow mass flow rate relationship; organizing the collected plurality of data pairs into a predetermined number of bins; Average the data pairs in each corresponding bin; as well as Each of the first quadratic equation relating the rough clean air filter pressure drop to airflow mass flow rate and the second quadratic equation relating the final clean air filter pressure drop to airflow mass flow rate is generated using the averaged clean air filter data pairs.

15. The self-calibrating air filter life monitoring system of claim 14, wherein: The electronic controller is also programmed to: determining polynomial coefficients of the second quadratic equation to generate the second quadratic equation; and The maximum clean air filter pressure drop of the clean air filter is determined using the final clean air filter pressure drop versus airflow mass flow rate relationship.

16. The self-calibrating air filter life monitoring system of claim 11 , wherein the electronic controller is further programmed to: determining atmospheric pressure downstream of the in-use air filter with the internal combustion engine shut off; determining an in-use air filter pressure at said low internal combustion engine speed; determining an in-use air filter pressure drop by calculating a difference between an atmospheric pressure downstream of the in-use air filter determined with the engine off and an in-use air filter pressure determined at the low engine speed; as well as The determined in-use air filter pressure drop at the first in-use air filter airflow mass flow rate is also used to relate the in-use air filter pressure drop to airflow mass flow rate.

17. The self-calibrating air filter life monitoring system of claim 16, wherein: The electronic controller is programmed to relate the in-use air filter pressure drop to the airflow mass flow rate in two stages, and is further programmed to: In a first stage, using the acquired first and second data sets of in-use air filter and the in-use air filter pressure drop, a rough in-use air filter pressure drop versus airflow mass flow rate is established to estimate a second in-use air filter pressure drop at the second in-use air filter airflow mass flow rate; generating a first quadratic equation to fit the second in-use air filter pressure drop and the second in-use air filter airflow mass flow rate to the rough in-use air filter pressure drop to airflow mass flow rate relationship; using the new first and second in-use air filter data sets and the first quadratic equation in a second stage to relate the final in-use air filter pressure drop to the airflow mass flow rate to estimate a new second in-use air filter pressure drop at the second in-use air filter airflow mass flow rate; as well as A second quadratic equation is generated to fit the new second in-use air filter pressure drop and the second in-use air filter airflow mass flow rate to the final in-use air filter pressure drop to airflow mass flow rate relationship.

18. The self-calibrating air filter life monitoring system of claim 17, wherein: In order to establish the relationship between the rough use air filter pressure drop and the air flow mass flow rate and the final use air filter pressure drop and the air flow mass flow rate, the electronic controller is programmed to: Collect multiple data pairs to refine the relationship between in-use air filter pressure drop and airflow mass flow rate; organizing the collected plurality of data pairs into a predetermined number of bins; Average the data pairs in each corresponding bin; as well as Each of the first quadratic equation relating the rough in-use air filter pressure drop to airflow mass flow rate and the second quadratic equation relating the final in-use air filter pressure drop to airflow mass flow rate is generated using the averaged data pairs of the in-use air filter.

19. The self-calibrating air filter life monitoring system of claim 18, wherein: determining polynomial coefficients of the second quadratic equation to generate the second quadratic equation; and The maximum in-use air filter pressure drop of the in-use air filter is determined using the relationship between the final in-use air filter pressure drop and the airflow mass flow rate.

20. A non-transitory computer-readable medium having stored thereon executable instructions for self-calibration of an internal combustion engine air filter life monitoring system, the executable instructions comprising: acquiring a first clean air filter data set defined by a first clean air filter pressure, a first clean air filter airflow mass flow rate, and a first clean air filter temperature via conditioning and interrogating corresponding sensors at a low internal combustion engine speed; acquiring a second clean air filter data set defined by a second clean air filter pressure, a second clean air filter airflow mass flow rate, and a second clean air filter temperature via adjusting and interrogating the respective sensors at an elevated internal combustion engine speed; establishing, via the electronic controller, a relationship between a clean air filter pressure drop and an airflow mass flow rate using the acquired clean air filter first data set and the acquired second data set; determining a maximum clean air filter pressure drop of the clean air filter at a preset maximum airflow mass flow rate using a relationship between clean air filter pressure drop and airflow mass flow rate; acquiring a first in-use air filter data set defined by a first in-use air filter pressure, a first in-use air filter airflow mass flow rate, and a first in-use air filter temperature via conditioning and interrogating respective sensors at the low internal combustion engine speed; acquiring a second in-use air filter data set defined by a second in-use air filter pressure, a second in-use air filter airflow mass flow rate, and a second in-use air filter temperature via conditioning and interrogating the respective sensors at the elevated internal combustion engine speed; establishing, via the electronic controller, a relationship between an in-use air filter pressure drop and an airflow mass flow rate using the acquired first and second data sets of the in-use air filter; Determining a maximum in-use air filter pressure drop of the in-use air filter at the preset maximum air flow rate using the relationship between the in-use air filter pressure drop and the air flow mass flow rate; comparing, via the electronic controller, the maximum air filter pressure drops of the clean air filter and the in-use air filter to calculate a difference between the maximum in-use air filter pressure drop and the maximum clean air filter pressure drop at the predetermined maximum airflow mass flow rate; determining and storing, via the electronic controller, a remaining useful life of the in-use air filter corresponding to the calculated pressure drop differential; as well as When the calculated pressure drop difference is equal to or greater than a predetermined value, the sensor signal is set.

Images