Diagnostic device for filters for internal combustion engines

Abstract

To appropriately diagnose a deterioration state of a filter of an internal combustion engine.SOLUTION: A CPU executes calculation processing for calculating integrated dust amount ADA that is integrated amount of dust accumulated after replacement of a filter. The CPU executes diagnosis processing for diagnosing a deterioration state of the filter on the basis of the integrated dust amount ADA and limit dust amount LDA. In the calculation processing, first, the CPU calculates dust amount DA per unit time by multiplying intake air amount GA per unit time by a dust rate DUR corresponding to an area where a vehicle traveled. In the calculation processing, next, the CPU calculates new integrated dust amount ADA by integrating the calculated dust amount DA per unit time to past integrated dust amount ADA.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a diagnostic device for a filter for an internal combustion engine. [Background technology]

[0002] Patent Document 1 describes a filter for an air conditioning system and a diagnostic device for the filter. The filter filters gas passing through a casing. The filter is replaceably housed in a rectangular frame-shaped casing. The diagnostic device for the filter diagnoses the deterioration state of the filter based on the differential pressure between the upstream and downstream sides of the filter. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-217616 Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of a filter housed in an air cleaner in an intake passage of an internal combustion engine, even if the deterioration state of the filter is the same, the differential pressure between the upstream and downstream sides of the filter can vary greatly depending on the operating conditions of the internal combustion engine. Therefore, the filter monitoring device described in Patent Document 1 may not be able to properly diagnose the deterioration state of the filter for the internal combustion engine. [Means for solving the problem]

[0005] In order to solve the above problems, the present invention provides a diagnostic device for diagnosing a filter that is housed in an air cleaner located in the intake passage of an internal combustion engine and collects dust flowing through the intake passage, the diagnostic device comprising a memory device and an execution device, wherein the memory device stores a limit dust amount, which is the limit amount of dust that can accumulate on the filter, and a dust rate, which indicates the proportion of dust in the air, and the execution device executes a calculation process to calculate an accumulated dust amount, which is the accumulated amount of dust that has accumulated since the filter was replaced, and a diagnostic process to diagnose the deterioration state of the filter based on the accumulated dust amount and the limit dust amount, and the calculation process calculates the dust amount per unit time by multiplying the intake air amount per unit time by the dust rate corresponding to the driving area in which the vehicle has traveled, and calculates a new accumulated dust amount by integrating the calculated dust amount per unit time with the previous accumulated dust amount.

[0006] According to the above configuration, the execution device calculates the dust amount per unit time by multiplying the intake air volume by the dust rate. Next, the execution device calculates a new accumulated dust amount by integrating the dust amount per unit time with the previous accumulated dust amount. The execution device then diagnoses the deterioration state of the filter based on the accumulated dust amount and the limit dust amount. Therefore, the filter diagnosis device can diagnose the deterioration state of the filter without requiring a differential pressure between the upstream and downstream sides of the filter. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram of a communication system. [Figure 2] FIG. 2 is a flowchart showing a series of processes performed by the diagnostic program. DETAILED DESCRIPTION OF THE INVENTION

[0008] (One embodiment) Hereinafter, an embodiment of a diagnostic device for a filter for an internal combustion engine will be described with reference to the drawings.

[0009] <Communication system overview> 1, the communication system 10 includes a server 20 and a vehicle 30. The server 20 is connected to the vehicle 30 via an external communication network 40. The external communication network 40 is a wireless communication network such as a mobile phone network. Therefore, the server 20 and the vehicle 30 can communicate information with each other via the external communication network 40.

[0010] Although not shown, the server 20 has a CPU and a ROM. The CPU of the server 20 executes a program stored in the ROM. The server 20 stores a dust rate map indicating a plurality of travel areas and a dust rate DUR corresponding to each travel area. The plurality of travel areas may be, for example, a plurality of countries. The dust rate DUR is the proportion of dust in the air. The CPU of the server 20 receives location information of the vehicle 30 from the vehicle 30. The CPU of the server 20 also receives a request signal for the dust rate DUR from the vehicle 30 along with the location information. When the server 20 receives the request signal, it transmits information indicating the dust rate DUR of the travel area that includes the location information of the vehicle 30 to the vehicle 30.

[0011] <Vehicle Overview> The vehicle 30 includes an internal combustion engine 50, a communication device 60, a position information acquisition device 70, and a diagnostic device 80.

[0012] The internal combustion engine 50 is a drive source for the vehicle 30. The internal combustion engine 50 has an engine body 51. Although not shown, the engine body 51 has a cylinder and a crankshaft. The cylinder is a space for burning a mixture of fuel and intake gas. The crankshaft is connected to a piston located in the cylinder. Within the engine body 51, the space defined by the inner wall of the cylinder and the piston forms a combustion chamber. When fuel burns in the combustion chamber, the piston located in the cylinder moves. As a result, the crankshaft connected to the piston rotates.

[0013] The internal combustion engine 50 has an intake passage 52. The intake passage 52 is connected to the cylinders of the engine body 51. The intake passage 52 is a passage for allowing intake gas to flow from the outside of the internal combustion engine 50 into the combustion chamber.

[0014] The internal combustion engine 50 has an air cleaner 53 and a filter 54. The air cleaner 53 is located in the intake passage 52. The filter 54 is housed in the air cleaner 53. The air cleaner 53 filters the intake gas. Specifically, the filter 54 filters the intake gas to collect dust in the intake gas flowing through the intake passage 52.

[0015] The internal combustion engine 50 has an air flow meter 55. The air flow meter 55 is located in the intake passage 52 downstream of the air cleaner 53. The air flow meter 55 detects the intake air amount GA per unit time, which is the flow rate of intake gas flowing through the intake passage 52.

[0016] The internal combustion engine 50 has an exhaust passage 56. The exhaust passage 56 is connected to the cylinders of the engine body 51. The exhaust passage 56 is a passage for discharging exhaust gas from the cylinders of the engine body 51 to the outside of the internal combustion engine 50.

[0017] The communication device 60 communicates with the server 20 via the external communication network 40. Specifically, the communication device 60 receives signals from the server 20. The communication device 60 also transmits signals to the server 20.

[0018] The position information acquisition device 70 acquires position information indicating the position of the vehicle 30 based on, for example, signals from GNSS (Global Navigation Satellite System) satellites. The position information indicates the latitude, longitude, and altitude of the vehicle 30.

[0019] The diagnostic device 80 is a device that diagnoses the filter 54. The diagnostic device 80 acquires the intake air amount GA detected by the air flow meter 55. The diagnostic device 80 has a CPU 81, which is an execution device, a peripheral circuit 82, a ROM 83, a storage device 84, and a bus 85. The bus 85 connects the CPU 81, the peripheral circuit 82, the ROM 83, and the storage device 84 so that they can communicate with each other. The peripheral circuit 82 includes a circuit that generates a clock signal that regulates internal operations, a power supply circuit, a reset circuit, etc. The ROM 83 pre-stores various programs that the CPU 81 uses to execute various controls. The CPU 81 diagnoses the filter 54 by executing the various programs stored in the ROM 83.

[0020] The storage device 84 stores a limit dust amount LDA, which is the limit amount of dust that can accumulate on the filter 54. The limit dust amount LDA is an amount that is determined in advance through testing and simulation for each type of filter 54. For example, the larger the filtering area of ​​the filter 54, the larger the value of the limit dust amount LDA. When the filter 54 is replaced, the limit dust amount LDA is updated by a dealer or the like to a value that corresponds to the type of the new filter 54 that has been replaced.

[0021] The storage device 84 also stores an accumulated dust amount ADA, which is the accumulated amount of dust that has accumulated since the filter 54 was replaced. The accumulated dust amount ADA is reset to zero by a dealer or the like when the filter 54 is replaced.

[0022] <Program to obtain dust rate for driving area> The ROM 83 stores a dust rate acquisition program for acquiring the dust rate DUR of the travel area of ​​the vehicle 30. The CPU 81 acquires the dust rate DUR of the travel area, which is the area in which the vehicle 30 travels, by repeatedly executing the dust rate acquisition program at a predetermined cycle.

[0023] Specifically, when the CPU 81 executes the dust rate acquisition program, it first transmits the location information acquired by the location information acquisition device 70 to the server 20. The CPU 81 also transmits a request signal for the dust rate DUR to the server 20. Next, the CPU 81 receives information indicating the dust rate DUR from the server 20. The dust rate DUR received at this time is the dust rate DUR of the traveling area that includes the location information transmitted by the CPU 81. The CPU 81 then updates the value of the dust rate DUR of the traveling area stored in the storage device 84 to the newly received dust rate DUR. By repeatedly executing this dust rate DUR acquisition program, the storage device 84 constantly stores the dust rate DUR of the traveling area of ​​the vehicle 30.

[0024] <Filter diagnostic program> The ROM 83 stores a diagnostic program for diagnosing the deterioration state of the filter 54, with the filter 54 as the diagnostic target. The CPU 81 repeatedly executes the diagnostic program at a predetermined cycle. The cycle is defined so that the diagnostic program is repeatedly executed at each unit time.

[0025] 2, when the CPU 81 starts the diagnostic program, it first executes the process of step S11. In step S11, the CPU 81 calculates the amount of dust DA accumulated on the filter 54 per unit time. Specifically, the CPU 81 calculates the amount of dust DA per unit time by multiplying the intake air amount GA obtained from the air flow meter 55 by the dust rate DUR stored in the storage device 84. Thereafter, the CPU 81 proceeds to the process of step S12.

[0026] In step S12, the CPU 81 updates the accumulated dust amount ADA. Specifically, the CPU 81 adds the dust amount DA calculated in step S11 to the accumulated dust amount ADA stored in the storage device 84. The CPU 81 then updates the accumulated dust amount ADA stored in the storage device 84 with the value obtained by the addition as the new accumulated dust amount ADA. In this embodiment, steps S11 and S12 implement the calculation process for calculating the accumulated dust amount ADA. Thereafter, the CPU 81 proceeds to step S13.

[0027] In step S13, the CPU 81 calculates the deterioration rate DER. Specifically, the CPU 81 divides the accumulated dust amount ADA updated in step S13 by the limit dust amount LDA stored in the storage device 84. The CPU 81 then multiplies the value obtained by the division by 100 to calculate the deterioration rate DER. In other words, the deterioration rate DER is a value expressed as a percentage. The CPU 81 then proceeds to step S14.

[0028] In step S14, the CPU 81 performs a diagnostic process. In the diagnostic process, the deterioration state of the filter 54 is diagnosed based on the accumulated dust amount ADA and the limit dust amount LDA. Specifically, the CPU 81 determines whether the deterioration rate DER calculated from the accumulated dust amount ADA and the limit dust amount LDA is equal to or greater than a predetermined specified rate RR. The specified rate RR is specified in advance by testing or simulation as the proportion of the accumulated dust amount ADA that is reasonably close to the limit dust amount LDA. For example, the specified rate RR is 90%.

[0029] When the deterioration rate DER is smaller than the specified rate RR (S14: NO), the CPU 81 ends the current series of processes. That is, when the CPU 81 determines that the deterioration state of the filter 54 is not deteriorated, the CPU 81 ends the current series of processes.

[0030] On the other hand, when the deterioration rate DER is equal to or greater than the specified rate RR (S14: YES), the CPU 81 proceeds to step S15. In step S15, the CPU 81 performs a warning process. In the warning process, the CPU 81 displays information on a display or the like of the vehicle 30 indicating that it is time to replace the filter 54. Thereafter, the CPU 81 ends this series of processes. Note that the display or the like resulting from the warning process is hidden by the dealer or the like when the filter 54 is replaced.

[0031] (Operation of the embodiment) According to the above embodiment, when the internal combustion engine 50 is driven, intake gas flows through the intake passage 52. Then, the intake gas is filtered by the air cleaner 53, and dust contained in the intake gas accumulates on the filter 54.

[0032] (Effects of the embodiment) According to the above embodiment, the CPU 81 calculates the dust amount DA per unit time by multiplying the intake air amount GA by the dust rate DUR of the region in which the vehicle 30 is traveling. Next, the CPU 81 calculates a new accumulated dust amount ADA by adding the dust amount DA per unit time to the previous accumulated dust amount ADA. The CPU 81 then diagnoses the deterioration state of the filter 54 based on the accumulated dust amount ADA and the limit dust amount LDA calculated in this manner. Therefore, the diagnosis device 80 can diagnose the deterioration state of the filter 54 without requiring a differential pressure between the upstream and downstream sides of the filter 54.

[0033] (Other embodiments) The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0034] In the above embodiment, the server 20 stores the dust ratio map, but the dust ratio map may also be stored in the storage device 84 of the diagnostic device 80. That is, the storage device 84 may obtain the dust ratio DUR of the area in which the vehicle 30 is traveling from the server 20 and store it, or may store the dust ratio map and obtain the dust ratio DUR corresponding to the area in which the vehicle 30 is traveling from the dust ratio map. In this case, the vehicle 30 does not need to be connected to the server 20.

[0035] The dust rate map may correspond to the dust rate DUR for each driving area and for each fixed time period. For example, the dust rate DUR may be determined in advance for each of 24 hours into which a day is divided.

[0036] The dust ratio map may be created based on, for example, the dust amount DA actually measured when the vehicle 30 was traveling in the past. In the above embodiment, the CPU 81 stores the accumulated dust amount ADA calculated by the calculation process, but the accumulated dust amount ADA does not have to be stored in the storage device 84. In this case, time series data of the intake air amount GA and time series data of the dust rate DUR of the driving area are stored, and the accumulated dust amount ADA may be calculated each time from these time series data.

[0037] In the above embodiment, the diagnostic process produces two types of diagnostic results: "degraded" or "not degraded." However, the degree of degradation may also be diagnosed, for example, using the degradation rate DER. Furthermore, the distance that can be traveled with the current filter 54 may be calculated based on the degradation rate DER, and the distance may be notified to the user. Calculating the distance that can be traveled in this way is also a type of diagnosis of the degradation state of the filter 54.

[0038] In the above embodiment, the deterioration rate DER is used to perform the diagnostic process, but the deterioration rate is not limited to the deterioration rate DER, and parameters calculated based on the accumulated dust amount ADA and the limit dust amount LDA may be used. For example, the value obtained by subtracting the accumulated dust amount ADA from the limit dust amount LDA may be used as the allowable dust amount. [Explanation of symbols]

[0039] 10...Communication system 20...Server 30...Vehicle 40...External communication line network 50...Internal combustion engine 51...Engine body 52...Intake passage 53...Air cleaner 54...Filter 55...Air flow meter 56...Exhaust passage 60...Communication device 70...Location information acquisition device 80...Diagnostic device 81...CPU 82...Peripheral circuit 83...ROM 84...Storage device 85...Bus

Claims

[Claim 1] A diagnostic device for diagnosing a filter housed in an air cleaner located in an intake passage of an internal combustion engine and for collecting dust flowing through the intake passage, a storage device and an execution device, the storage device stores a limit dust amount, which is a limit amount of dust that can be accumulated on the filter, and a dust rate, which indicates a rate of dust in the air; The execution device A calculation process for calculating an integrated dust amount, which is an integrated amount of dust accumulated since the filter was replaced; a diagnosis process for diagnosing a deterioration state of the filter based on the accumulated dust amount and the limit dust amount; In the calculation process, the amount of dust per unit time is calculated by multiplying the intake air amount per unit time by the dust rate corresponding to the travel area in which the vehicle traveled, and the calculated amount of dust per unit time is added to the past accumulated amount of dust to calculate a new accumulated amount of dust. A diagnostic device for filters for internal combustion engines.

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