JP7803235B2 - Diagnostic device for filters for internal combustion engines - Google Patents

Description

The present invention relates to a diagnostic device for filters used in internal combustion engines.

Patent Document 1 describes a filter for air conditioning equipment 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 filter diagnostic device diagnoses the deterioration state of the filter based on the differential pressure between the upstream and downstream sides of the filter.

Japanese Patent Application Laid-Open No. 2017-217616

In the case of a filter housed in an air cleaner in the intake passage of an internal combustion engine, even if the filter's deterioration state is the same, the pressure difference between the upstream and downstream sides of the filter can change significantly 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 an internal combustion engine filter.

To solve the above problems, the present invention provides a diagnostic device for diagnosing a filter housed in an air cleaner located in the intake passage of an internal combustion engine and collecting dust flowing through the intake passage. The diagnostic device includes a storage device and an execution device. The storage device stores a dust limit 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. The execution device executes a calculation process that calculates an accumulated dust amount, which is the accumulated amount of dust that has accumulated since the filter was replaced, and a diagnostic process that diagnoses the deterioration state of the filter based on the accumulated dust amount and the dust limit amount. The calculation process calculates the dust amount per unit time by multiplying the intake air volume per unit time by the dust rate corresponding to the area in which the vehicle has traveled, and calculates a new accumulated dust amount by adding the calculated dust amount per unit time to the previous accumulated dust amount.

With 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 adding the dust amount per unit time to 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.

FIG. 1 is a schematic diagram of a communication system. FIG. 2 is a flowchart showing a series of processes performed by the diagnostic program.

(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.

<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.

The server 20 has a CPU and ROM, not shown. The CPU of the server 20 executes programs stored in the ROM. The server 20 stores a dust rate map that indicates multiple travel areas and the dust rate DUR corresponding to each travel area. The multiple travel areas are, for example, multiple 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 to the vehicle 30 that indicates the dust rate DUR of the travel area that includes the location information of the vehicle 30.

<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 .

The internal combustion engine 50 is the driving source of 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 inside the cylinder. The space of the engine body 51 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 inside the cylinder moves. As a result, the crankshaft connected to the piston rotates.

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 flowing intake gas from outside the internal combustion engine 50 into the combustion chamber.

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.

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 volume GA per unit time, which is the flow rate of intake gas flowing through the intake passage 52.

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.

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.

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

The diagnostic device 80 is a device that diagnoses the filter 54. The diagnostic device 80 acquires the intake air volume 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, peripheral circuit 82, ROM 83, and 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 operation, a power supply circuit, a reset circuit, etc. The ROM 83 pre-stores various programs that the CPU 81 uses to perform various controls. The CPU 81 diagnoses the filter 54 by executing the various programs stored in the ROM 83.

The memory device 84 stores a dust limit amount LDA, which is the limit amount of dust that can accumulate on the filter 54. The dust limit amount LDA is an amount 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 dust limit amount LDA. When the filter 54 is replaced, the dust limit amount LDA is updated to a value corresponding to the type of new filter 54, such as by a dealer.

The memory device 84 also stores the 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 other person when the filter 54 is replaced.

<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 area in which the vehicle 30 is traveling. The CPU 81 acquires the dust rate DUR of the area in which the vehicle 30 is traveling by repeatedly executing the dust rate acquisition program at a predetermined cycle.

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.

<Filter diagnostic program>
The ROM 83 stores a diagnostic program for diagnosing the deterioration state of the filter 54, with the filter 54 being 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.

As shown in FIG. 2, when the CPU 81 starts the diagnostic program, it first executes the processing 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 volume GA obtained from the air flow meter 55 by the dust rate DUR stored in the memory device 84. The CPU 81 then proceeds to step S12.

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 memory device 84. The CPU 81 then updates the accumulated dust amount ADA stored in the memory 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. The CPU 81 then proceeds to step S13.

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.

In step S14, the CPU 81 performs diagnostic processing. In the diagnostic processing, 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 through testing or simulation as the ratio at which the accumulated dust amount ADA is reasonably close to the limit dust amount LDA. For example, the specified rate RR is 90%.

When the deterioration rate DER is less than the specified rate RR (S14: NO), the CPU 81 ends the current series of processes. In other words, when the CPU 81 determines that the deterioration state of the filter 54 is not deteriorated, it ends the current series of processes.

On the other hand, if 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. The CPU 81 then ends this series of processes. Note that the display or the like resulting from the warning process can be hidden by the dealer or the like when the filter 54 is replaced.

(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, as the intake gas is filtered by the air cleaner 53, dust contained in the intake gas accumulates on the filter 54.

(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.

(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.

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

- The dust rate map may correspond to a dust rate DUR for each driving area and for each fixed time period. For example, the dust rate DUR may be predetermined for each of the 24 hours into which a day is divided.

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.

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

- In the above embodiment, the deterioration rate DER is used to perform diagnostic processing, but parameters calculated based on the accumulated dust amount ADA and the limit dust amount LDA can be used, so long as they are not limited to the deterioration rate DER. 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.

10...Communication system 20...Server 30...Vehicle 40...External communication 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 (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 area in which the vehicle has traveled, and the calculated amount of dust per unit time is added to the previous accumulated dust amount to calculate a new accumulated dust amount.