Determination device, determination method, control program, and recording medium

Abstract

To determine whether or not a DPF should be cleaned.SOLUTION: A determination device (10) includes: an intake air amount acquisition section (11) that acquires intake air amount of an engine (1); a differential pressure acquisition section (12) that acquires differential pressure of a DPF (4); a determination section (14) that determines whether or not the DPF (4) should be cleaned by using a relation with the intake air amount and the differential pressure; and an output section (15) that when the determination section (14) determines that the DPF should be cleaned, outputs the determination result.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a determination device and the like that determines the timing to clean a DPF (Diesel Particulate filter) used in a diesel engine. [Background technology]

[0002] Diesel engines have been known for some time. Diesel engines use diesel fuel, which has a lower ignition point than gasoline, and inject the diesel fuel into highly compressed, high-temperature air to cause spontaneous combustion and drive the pistons. For example, Patent Document 1 describes an example of a diesel engine.

[0003] Diesel vehicles currently on the road are fitted with diesel particulate filters (DPFs) to reduce PM emissions in accordance with exhaust gas regulations. DPFs remove soot and other particles from diesel engine exhaust gases.

[0004] DPFs undergo periodic regeneration to prevent the soot removed from exhaust gas from clogging the filter by burning the soot at high temperatures. However, the particulate matter removed by DPFs from exhaust gases is not just soot; it also includes ash. Ash is a calcium compound and metal-based additive that is not combusted and therefore accumulates even after regeneration. Ash accumulation clogs the DPF, reducing its filtering performance. Therefore, DPFs must be periodically cleaned to remove ash. However, DPFs are typically used with oxidation catalysts, and cleaning reduces the catalyst's performance. Therefore, frequent cleaning is not recommended. On the other hand, delayed cleaning can lead to ash accumulation, leading to cracks and corrosion in the DPF, necessitating replacement. Therefore, determining when to clean the DPF is a difficult issue.

[0005] Nowadays, DPF cleaning is often performed at the following times: (1) When a diesel vehicle tries to accelerate, the speed does not increase. (2) The frequency of the DPF manual regeneration function prompt has become shorter. Another example is (3) once every several years during the annual vehicle inspection. However, in (1), the DPF is often already damaged and in need of replacement. In (2), there is no correlation between the frequency of the manual regeneration function prompt and the degree of clogging of the DPF, so it is not a meaningful timing. In (3), cleaning is often not necessary at the time, which deteriorates the oxidation catalyst. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 58-222916 Summary of the Invention [Problem to be solved by the invention]

[0007] As mentioned above, in the prior art, when to clean the DPF is determined empirically by the user, and there is no established method for determining the appropriate timing for cleaning the DPF. In addition, it is not clear what phenomena occur inside the DPF, and there is no technology to accurately determine the degree of clogging of the DPF.

[0008] One aspect of the present invention has been made in consideration of the above-mentioned problems, and its purpose is to realize a determination device or the like that can appropriately determine whether or not the DPF is in a state that requires cleaning. [Means for solving the problem]

[0009] The inventors of the present application have discovered that it is possible to determine whether the DPF needs to be cleaned by using the relationship between the amount of intake air taken into the engine and the differential pressure before and after passing through the DPF.

[0010] Therefore, in order to solve the above-mentioned problem, a determination device according to one embodiment of the present invention is a determination device that determines whether a DPF provided in an exhaust path of a diesel engine is in a state where it should be cleaned, and includes an intake air volume acquisition unit that acquires the intake air volume of the diesel engine, a differential pressure acquisition unit that acquires a differential pressure, which is the difference in air pressure before and after the exhaust from the diesel engine passes through the DPF, a determination unit that determines whether the DPF is in a state where it should be cleaned using a set of the intake air volume and the differential pressure acquired at the same time, and an output unit that outputs a signal to that effect if the determination unit determines that the DPF is in a state where it should be cleaned.

[0011] Furthermore, a determination method according to one embodiment of the present invention is a method for determining whether a DPF provided in an exhaust path of a diesel engine is in a state where it should be cleaned, and includes an intake air volume acquisition step for acquiring the intake air volume of the diesel engine; a differential pressure acquisition step for acquiring a differential pressure which is the difference in air pressure before and after the exhaust from the diesel engine passes through the DPF; a determination step for determining whether the DPF is in a state where it should be cleaned using a set of the intake air volume and the differential pressure acquired at the same time; and an output step for outputting a result to that effect if it is determined in the determination step that the DPF is in a state where it should be cleaned. [Effects of the Invention]

[0012] According to one aspect of the present invention, the intake air amount and the differential pressure are used to determine whether the DPF is in a state where it needs to be cleaned, thereby providing the effect of being able to appropriately determine whether the DPF is in a state where it needs to be cleaned. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram showing an overall outline of a diesel engine system including a determination device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a functional block diagram showing the configuration of a main part of a determination device. [Figure 3] 5A and 5B are diagrams illustrating examples of intake air amount data and differential pressure data. [Figure 4] 5A and 5B are diagrams showing changes over time in intake air amount and differential pressure; [Figure 5] 10 is a graph showing an example of a regression line when the intake air amount and the differential pressure are plotted on a two-dimensional graph. [Figure 6] FIG. 10 is a diagram showing an example of a change in the slope of a regression line over time. [Figure 7] FIG. 10 is a diagram illustrating an example of a notification. [Figure 8] FIG. 10 is a diagram showing an example of displaying a determination result. [Figure 9] 10 is a flowchart showing a flow of processing in the determination device. DETAILED DESCRIPTION OF THE INVENTION

[0014] [Embodiment 1] An embodiment of the present invention will be described in detail below. First, a diesel engine system 100 including a determination device 10 according to this embodiment will be described with reference to FIG. 1. FIG. 1 is a diagram showing an overall outline of the diesel engine system 100. The diesel engine system 100 is an engine system mounted on an automobile such as a truck, for example. As shown in FIG. 1, the diesel engine system 100 includes an engine 1, a DPF device 2 provided in an exhaust path of the engine 1, a part of the exhaust gas passing through the exhaust path of the engine 1, and a DPF device 3. of The DPF device 2 includes an EGR cooler 5 for taking in the exhaust gas into the engine 1, an ECU (Electronic Control Unit) 8, and a determination device 10. The DPF device 2 also includes an oxidation catalyst 3 and a DPF 4.

[0015] The diesel engine system 100 is also equipped with a differential pressure sensor 6 that measures the difference in air pressure before and after the exhaust gas passing through the DPF 4, and an air flow sensor 7 that measures the amount of intake air taken into the engine 1. The data measured by the differential pressure sensor 6 and the air flow sensor 7 are sent to an ECU 8 that electronically controls the engine 1.

[0016] It should be noted that the parts of the diesel engine system 100 other than the determination device 10 can be realized by a conventional diesel engine system, and therefore detailed description thereof will be omitted.

[0017] Next, the determination device 10 will be described with reference to Fig. 2. Fig. 2 is a functional block diagram showing the configuration of the main parts of the determination device 10. As shown in Fig. 2, the determination device 10 includes an intake air amount obtaining unit 11, a differential pressure obtaining unit 12, a memory unit 13, a determination unit 14, and an output unit 15.

[0018] The intake air amount obtaining unit 11 obtains the amount of intake air taken into the engine 1 from the airflow sensor 7. The intake air amount obtaining unit 11 may periodically obtain the intake air amount. The obtained intake air amount is then stored in the memory unit 13 as intake air amount data 31 together with the acquisition date and time.

[0019] The differential pressure acquisition unit 12 acquires, from the differential pressure sensor 6, a differential pressure, which is the difference in air pressure between before and after exhaust gas from the engine 1 passes through the DPF 4. The differential pressure acquisition unit 12 may periodically acquire the differential pressure. The acquired differential pressure is then stored in the storage unit 13 as differential pressure data 32 together with the acquisition date and time.

[0020] The intake air volume acquisition unit 11 acquires the intake air volume and the differential pressure acquisition unit 12 acquires the differential pressure at the same time or approximately the same time. Therefore, the intake air volume data 31 and the differential pressure data 32 are acquired at the same time or approximately the same time.

[0021] FIG. 3 shows examples of intake air volume data 31 and differential pressure data 32. As shown in FIG. 3, for example, intake air volume data 31 stores an associated date and time of acquisition and an intake air volume (g / s). Similarly, differential pressure data 32 stores an associated date and time of acquisition and a differential pressure (kPa). In the example shown in FIG. 3, data such as "intake air volume at 6:00, August 1, 2022 is 48 (g / s)," "intake air volume at 6:01, August 1, 2022 is 48 (g / s)," "intake air volume at 6:02, August 1, 2022 is 50 (g / s)," and so on are stored. Here, g represents grams and s represents seconds. Also, the differential pressure at 6:00 on 8 / 1 / 2022 is 2.5 (kPa), the differential pressure at 6:01 on 8 / 1 / 2022 is 2.5 (kPa), the differential pressure at 6:02 on 8 / 1 / 2022 is 2.8 (kPa), and so on are stored.

[0022] The intake air amount obtaining section 11 and the differential pressure obtaining section 12 may obtain the intake air amount and the differential pressure only when at least one of the following obtaining conditions 1 to 5 is satisfied. 1. Engine 1 is not idling. For example, the vehicle accelerator is depressed. 2.Neither automatic regeneration, manual regeneration, nor forced regeneration of DPF4 has been performed. 3. The temperature of DPF4 is 300°C (sixth threshold) or less. 4. The PTO (Power Take Off) of the vehicle equipped with engine 1 is not in use. 5. The temperature of the radiator of a vehicle equipped with engine 1 is 60°C (seventh threshold) or higher.

[0023] When the engine 1 is idling, or when the temperature of the DPF 4 is too high, it is difficult to grasp the exact state of the DPF 4. Therefore, by setting the above acquisition conditions, it is possible to acquire appropriate data for grasping the state of the DPF 4.

[0024] Fig. 4 shows an example of a graph representing the change over time in the intake air amount acquired by the intake air amount acquisition unit 11 and the differential pressure acquired by the differential pressure acquisition unit 12. In Fig. 4, 401 indicates the intake air amount (g / s) on the vertical axis and the time on the horizontal axis. In Fig. 4, 402 indicates the differential pressure (kPa) on the vertical axis and the time on the horizontal axis.

[0025] The determination unit 14 uses the relationship between the intake air amount acquired by the intake air amount acquisition unit 11 and the differential pressure acquired by the differential pressure acquisition unit 12 to determine whether the state of the DPF 4 is in a state where it should be cleaned.

[0026] Specifically, the determination unit 14 derives a regression line indicating the relationship between the intake air volume and the differential pressure from pairs of intake air volume and differential pressure acquired during a predetermined period up to the determination time point. Then, the determination unit 14 compares the slope of the derived regression line with a preset threshold value (first threshold value) to determine whether the state of the DPF 4 is in a state where cleaning is required. The predetermined period may be from 24 hours before the determination time point to the determination time point, or from 12 hours before the determination time point, or from 6 hours before the determination time point. Alternatively, the predetermined period may be the day before the determination date or all business days.

[0027] The regression line is calculated as follows. First, pairs of the intake air volume acquired by the intake air volume acquisition unit 11 and the differential pressure acquired by the differential pressure acquisition unit 12 within a predetermined period are plotted on a scatter diagram with the vertical axis representing the differential pressure and the horizontal axis representing the intake air volume. As a result, multiple points (intake air volume, differential pressure) are plotted on the scatter diagram, with the X coordinate representing the intake air volume and the Y coordinate representing the differential pressure. Since it is well known to obtain a regression line based on the coordinates of multiple points, a regression line showing the relationship between the intake air volume and the differential pressure can be derived in this way. For example, the regression line can be derived using the least squares method.

[0028] An example of a regression line is shown in Figure 5. In Figure 5, points representing pairs of intake air volume and differential pressure obtained within a predetermined period are plotted on a scatter plot with the vertical axis representing differential pressure (kPa) and the horizontal axis representing intake air volume (g / s). The regression line L derived from these points is also shown. If the equation representing this regression line L is y=ax+b, then the slope of the regression line L is a. In other words, the slope a can be said to be the amount of change in differential pressure relative to the intake air volume.

[0029] If the slope a exceeds a threshold value, the determination unit 14 determines that the DPF 4 is in a state that requires cleaning. For example, assume that the transition of the slope of the regression line is as shown in Figure 6. Here, if the threshold value is 0.04 and the DPF 4 is determined to be in a state that requires cleaning when the slope exceeds the threshold value, the DPF 4 is determined to be in a state that requires cleaning at time X.

[0030] The determination unit 14 may make the determination based on whether the slope exceeds the threshold value multiple times, rather than just once. That is, the determination unit 14 may repeat the determination at predetermined intervals, and determine that the DPF 4 is in a state that requires cleaning when the number of times the slope exceeds the threshold value exceeds a predetermined number. Alternatively, the determination unit 14 may determine that the DPF 4 is in a state that requires cleaning when the number of times the slope exceeds the threshold value consecutively exceeds a predetermined number. Alternatively, the determination unit 14 may determine that the DPF 4 is in a state that requires cleaning when the number of times the slope exceeds the threshold value exceeds a predetermined number within a predetermined period. Alternatively, the determination unit 14 may determine that the DPF 4 is in a state that requires cleaning when the ratio of the number of times the slope exceeds the threshold value to the number of comparisons within a predetermined period exceeds a threshold.

[0031] Alternatively, a moving average of the change in the slope may be calculated, and whether or not the DPF 4 is in a state where it should be cleaned may be determined based on whether or not this moving average exceeds a threshold value.

[0032] The timing at which the determination unit 14 makes the determination may be every few minutes to every few hours, or may be once a day, as long as the engine 1 is running. When making the determination once a day, the determination may be made, for example, when the engine 1 is started for the first time that day, or at a predetermined time.

[0033] The determination unit 14 may determine not only whether the DPF 4 is in a state where it should be cleaned, but also whether the DPF 4 is approaching a state where it should be cleaned by setting a threshold value that is slightly smaller than the threshold value used when determining that the DPF 4 is in a state where it should be cleaned.

[0034] When the determination unit 14 determines that the state of the DPF 4 is in a state where cleaning is required, the output unit 15 outputs that information. The output destination of the output unit 15 may be, for example, a notification unit that notifies the DPF 4 using sound, light, or the like, or may be a management device managed by an operation manager or the like.

[0035] The output unit 15 may also output the determination result by the determination unit 14 and the slope of the regression line at that time to the management device 801 (FIG. 8). That is, the output unit 15 may output not only that the state of the DPF 4 is in a state that requires cleaning, but also that the determination unit 14 has determined that the state of the DPF 4 is not in a state that requires cleaning.

[0036] FIG. 7 shows an example of the notification unit 701. In the example shown in FIG. 7, the notification unit 701 is provided on the dashboard of the automobile. The notification unit 701, for example, lights up in response to an output from the output unit 15. This allows the driver to recognize that the DPF 4 is in a state where it should be cleaned. The notification unit 701 may notify by changing color or by flashing, instead of turning on and off. For example, the notification unit 701 may always light up in green and turn red when there is an output from the output unit 15. Furthermore, when it is determined that the DPF 4 is approaching a state where it should be cleaned, the notification unit 701 may light up in yellow when the DPF 4 is approaching a state where it should be cleaned. The notification may also be made by outputting a sound.

[0037] FIG. 8 shows an example in which the output result from the output unit 15 is displayed on the management device 801. In the example shown in FIG. 8, the determination result of the determination device 10 is displayed on the management device 801 of the operations manager. In the display example 802 shown in FIG. 8, the slope and evaluation are displayed for each date. For example, on "2022 / 8 / 1", ​​the slope is "0.035" and the evaluation is "○ (green)". "Green" indicates that the display is in green. Also, on "2022 / 8 / 7", the slope is "0.04" and the evaluation is "○ (red)". Here, the red display indicates that the DPF 4 is in a state where it should be cleaned. Therefore, by checking this display example 802, the operations manager can recognize that the DPF 4 was in a state where it should be cleaned on 2022 / 8 / 7.

[0038] By making the operation manager aware of the judgment result of the judgment device 10, even if there is a difference in understanding between the driver and the operation manager, it is possible to objectively grasp the state of the DPF 4.

[0039] [Processing flow] Next, the flow of processing in the determination device 10 will be described with reference to Fig. 9. Fig. 9 is a flowchart showing the flow of processing in the determination device 10.

[0040] As described above, in the determination device 10, the intake air amount obtaining unit 11 repeatedly obtains the intake air amount and stores it in the memory unit 13, and the differential pressure obtaining unit 12 repeatedly obtains the differential pressure and stores it in the memory unit 13.

[0041] First, the determination unit 14 acquires data acquired during a predetermined period from the intake air volume data 31 and the differential pressure data 32 stored in the memory unit 13 (S101, intake air volume acquisition step, differential pressure acquisition step). Next, the determination unit 14 derives a regression line from the acquired pair of intake air volume and differential pressure (S102). Then, when the slope of the regression line exceeds a threshold value (YES in S103, determination step), the output unit 15 outputs a signal indicating that the DPF 4 is in a state that requires cleaning (S104, output step).

[0042] [Modification] The determination unit 14 may determine whether the DPF 4 is in a state where it should be cleaned based on not only the slope of the regression line but also other conditions.

[0043] For example, the determination unit 14 may determine that the DPF 4 is approaching a state where it should be cleaned when the slope of the regression line exceeds a second threshold value that is smaller than the first threshold value. 6 When at least one of the above conditions is satisfied, it may be determined that the DPF 4 needs to be cleaned. 1. The temperature of the exhaust gas from the engine 1 has changed significantly. For example, the temperature has changed by more than a first predetermined temperature within a first predetermined time. 2. The temperature of the exhaust gas before passing through the DPF4 is higher than the temperature of the exhaust gas after passing through it, and the temperature difference between the exhaust gas before and after passing through the DPF4 exceeds 80°C (third threshold). In this case, combustion inside the DPF4 may be hindered, and automatic regeneration may not be performed sufficiently. Note that if the temperature difference between the exhaust gas before and after passing through the DPF4 exceeds 80°C for five minutes or more, it may be determined that the DPF4 needs to be cleaned. 3. The temperature of the exhaust gas before passing through the DPF4 is lower than the temperature of the exhaust gas after passing through it, and the temperature difference between the exhaust gas before and after passing through the DPF4 exceeds 200°C (fourth threshold). In this case, abnormal combustion of soot may occur inside the DPF4, causing internal melting. Note that if the temperature difference between the exhaust gas before and after passing through the DPF4 exceeds 200°C and the temperature of the exhaust gas after passing through is 600°C or higher, it may be determined that the DPF4 is in a state where it needs to be cleaned. 4 The temperature of the exhaust gas before or after passing through the DPF4 exceeds 700°C (fifth threshold). 5 A diagnostic fault code is output from the ECU 8 that controls the engine 1. For example, the ECU 8 outputs a diagnostic fault code (DTC) such as a DPF4 high temperature abnormality, soot accumulation abnormality, or EGR abnormality. 6The mileage until automatic DPF4 regeneration occurs has been shorter than before for a certain period of time. For example, if the automatic regeneration interval, which normally occurs about once every 200 km, becomes extremely short.

[0044] The determination unit 14 can acquire each piece of data used for the above additional conditions from the ECU 8. Therefore, the determination unit 14 acquires these pieces of data from the ECU 8 and can determine whether the DPF 4 is in a state where it should be cleaned based on whether the additional conditions are satisfied in addition to the slope of the regression line.

[0045] As described above, the determination device 10 according to this embodiment determines whether the DPF 4 provided in the exhaust path of the engine 1 is in a state where it should be cleaned. The determination device 10 includes an intake air amount acquisition unit 11 that acquires the intake air amount of the engine 1, a differential pressure acquisition unit 12 that acquires a differential pressure, which is the difference in air pressure before and after the exhaust from the engine 1 passes through the DPF4, a determination unit 14 that determines whether the DPF4 is in a state where it should be cleaned using a set of the intake air amount and the differential pressure acquired at the same time, and an output unit 15 that outputs a result to that effect when the determination unit 14 determines that the DPF4 is in a state where it should be cleaned.

[0046] Delayed cleaning of the DPF4 can lead to cracks, melting, and other damage to the DPF4. When these problems occur, the DPF4 itself must be replaced. DPF4s are expensive, and users generally want to avoid unnecessary replacements.

[0047] According to the above configuration, it is possible to appropriately determine whether the DPF 4 is in a state where it should be cleaned, thereby reducing the chances that the user will miss the timing to clean the DPF 4. It is also possible to prevent the DPF 4 from being cleaned too many times unnecessarily. Therefore, the number of times the DPF 4 is cleaned can be minimized. Furthermore, it is possible to reduce the cost and time required for cleaning. Furthermore, it is possible to prevent unnecessary replacement, which contributes to reducing carbon dioxide emissions associated with the manufacture of new parts.

[0048] In addition, by cleaning the DPF4 at the appropriate time, the life of the DPF4 can be extended and the number of times it needs to be replaced can be reduced, which also reduces the cost and time required for replacement.

[0049] Furthermore, by preventing the vehicle itself from stopping due to a problem with the DPF4, the inconvenience of the vehicle being unable to move can be avoided. For example, if a truck carrying goods stops, the goods cannot be delivered as scheduled, which could lead to a loss of credibility for the delivery company and problems such as liability for damages. This can be prevented in advance.

[0050] Furthermore, if a problem with the DPF4 occurs despite the DPF4 being cleaned at the appropriate time, it is possible to assume that the cause is something other than the DPF4, which can lead to the discovery of malfunctions in other areas.

[0051] As mentioned above, optimizing cleaning timing also leads to decarbonization, which will contribute to achieving Goal 13 of the United Nations' Sustainable Development Goals (SDGs), such as "Take urgent action to combat climate change and its impacts."

[0052] [Software implementation example] The functions of the judgment device 10 (hereinafter referred to as the "device") can be realized by a program that causes a computer to function as the device, and a program that causes a computer to function as each control block of the device (particularly the judgment unit 14).

[0053] In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory) as hardware for executing the program. The control device and storage device execute the program, thereby realizing the functions described in each of the above embodiments.

[0054] The program may be non-transitory and may be recorded on one or more computer-readable recording media. The recording media may or may not be included in the device. In the latter case, the program may be supplied to the device via any wired or wireless transmission medium.

[0055] Furthermore, some or all of the functions of the control blocks can be realized by logic circuits. For example, an integrated circuit in which a logic circuit that functions as each of the control blocks is formed is also included in the scope of the present invention. In addition, the functions of the control blocks can also be realized by, for example, a quantum computer.

[0056] The above-described processing may be performed by AI (Artificial Intelligence). In this case, the AI ​​may run on the control device or on another device (for example, an edge computer or a cloud server).

[0057] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in the embodiments are also included in the technical scope of the present invention.

[0058] 〔summary〕 A determination device according to a first aspect of the present disclosure is a determination device for determining whether a DPF provided in an exhaust path of a diesel engine is in a state in which it should be cleaned, and includes an intake air volume acquisition unit that acquires the intake air volume of the diesel engine, a differential pressure acquisition unit that acquires a differential pressure, which is the difference in air pressure before and after exhaust from the diesel engine passes through the DPF, a determination unit that determines whether the DPF is in a state in which it should be cleaned using a set of the intake air volume and the differential pressure acquired at the same time, and an output unit that outputs a result to that effect when the determination unit determines that the DPF is in a state in which it should be cleaned.

[0059] A determination device according to a second aspect of the present disclosure is the determination device of the first aspect, wherein the determination unit determines a value of the intake air amount and the differential pressure derived from a pair of the intake air amount and the differential pressure acquired during a predetermined period. differential pressure The gradient of the regression line showing the relationship between the DPF and the first threshold value is compared to determine whether the DPF needs to be cleaned.

[0060] A determination device according to a third aspect of the present disclosure is the second aspect, wherein the determination unit determines that the DPF needs to be cleaned when a change in the differential pressure relative to the intake air amount exceeds a first threshold value.

[0061] In the determination device according to aspect 4 of the present disclosure, in aspect 2, the determination unit repeatedly compares the slope of the regression line with a threshold value at predetermined intervals, and determines that the DPF needs to be cleaned if the slope of the regression line exceeds the first threshold value a predetermined number of times in a predetermined period of time, or if the number of times the slope of the regression line exceeds the first threshold value exceeds a predetermined percentage.

[0062] In the determination device according to aspect 5 of the present disclosure, in any of aspects 2 to 4, the determination unit determines that the DPF is approaching a state in which it should be cleaned when the slope of the regression line exceeds a second threshold value that is smaller than the first threshold value.

[0063] A determination device according to a sixth aspect of the present disclosure is the same as in the fifth aspect, wherein the determination unit determines whether the slope of the regression line exceeds the second threshold and the following additional conditions (1) to ( 6 ) When at least one of the following conditions is met, (1) The temperature of the exhaust gas from the diesel engine has changed by a first predetermined temperature or more within a first predetermined time. (2) The temperature of the exhaust gas before passing through the DPF is higher than the temperature of the exhaust gas after passing through the DPF, and the temperature difference between the exhaust gas before and after passing through the DPF exceeds a third threshold value. (3) The temperature of the exhaust gas before passing through the DPF is lower than the temperature of the exhaust gas after passing through the DPF, and the temperature difference between the exhaust gas before and after passing through the DPF exceeds a fourth threshold value. (4) The temperature of the exhaust gas before or after passing through the DPF exceeds a fifth threshold. (5) A diagnostic code is output in the ECU that controls the diesel engine. (6) The period until the DPF automatic regeneration is performed has been shorter than the previous period for a certain period of time. It is determined that the DPF needs to be cleaned.

[0064] In the determination device according to aspect 7 of the present disclosure, in any of aspects 1 to 6, the intake air volume acquisition unit and the differential pressure acquisition unit acquire the intake air volume and the differential pressure only when acquisition conditions are satisfied.

[0065] In the determination device according to aspect 8 of the present disclosure, in the above-mentioned aspect 7, the acquisition conditions are at least one of the following: the diesel engine is not idling; none of automatic regeneration, manual regeneration, and forced regeneration of the DPF is being performed; the temperature of the DPF is equal to or lower than a sixth threshold; the PTO (Power Take Off) of a vehicle equipped with the diesel engine is not in use; and the temperature of the radiator of the vehicle is equal to or higher than a seventh threshold.

[0066] A determination method according to aspect 9 of the present disclosure is a determination method for determining whether a DPF provided in an exhaust path of a diesel engine is in a state where it should be cleaned, and includes an intake air volume acquisition step for acquiring the intake air volume of the diesel engine; a differential pressure acquisition step for acquiring a differential pressure which is the difference in air pressure before and after the exhaust from the diesel engine passes through the DPF; a determination step for determining whether the DPF is in a state where it should be cleaned using a set of the intake air volume and the differential pressure acquired at the same time; and an output step for outputting a result to that effect if it is determined in the determination step that the DPF is in a state where it should be cleaned.

[0067] The determination device according to each aspect of the present disclosure may be realized by a computer. In this case, the control program of the determination device 10 that causes the computer to operate as each part (software element) of the determination device to realize the determination device on the computer, and the computer-readable recording medium on which the control program is recorded, also fall within the scope of the present invention. [Explanation of symbols]

[0068] 1 engine 2 DPF device 3. Oxidation catalyst 4 DPF 5 EGR cooler 6 Differential pressure sensor 7. Airflow sensor 8 ECU 10 Judgment device 11. Intake air volume acquisition unit 12 Differential pressure acquisition unit 13 Storage section 14 Judgment section 15 Output section 31 Intake air volume data 32 Differential pressure data 100 Diesel Engine System

Claims

1. A determination device for determining whether a DPF (Diesel Particulate Filter) provided in an exhaust path of a diesel engine is in a state that requires cleaning, an intake air amount acquisition unit that acquires an intake air amount of the diesel engine; a differential pressure acquisition unit that acquires a differential pressure, which is a difference in air pressure between before and after exhaust gas from the diesel engine passes through the DPF; a determination unit that determines whether the DPF needs to be cleaned using a set of the intake air amount and the differential pressure that are simultaneously acquired; and an output unit that outputs a signal indicating that the DPF needs to be cleaned when the determination unit determines that the DPF needs to be cleaned.

2. 2. The determination device according to claim 1, wherein the determination unit compares a slope of a regression line, which is derived from a pair of the intake air amount and the differential pressure and indicates a relationship between the intake air amount and the differential pressure, with a first threshold value to determine whether the DPF is in a state that requires cleaning.

3. The determination device according to claim 2 , wherein the determination unit determines that the DPF needs to be cleaned when a change in the differential pressure relative to the intake air amount exceeds a first threshold value.

4. the determination unit repeatedly compares the slope of the regression line with a threshold value at predetermined intervals, When the slope of the regression line exceeds the first threshold value a predetermined number of times in succession, or If the number of times that the slope of the regression line with respect to the number of comparisons exceeds a first threshold value exceeds a predetermined percentage within a predetermined period, The determination device according to claim 2 , wherein the determination device determines that the DPF needs to be cleaned.

5. The determination device according to claim 2 , wherein the determination unit determines that the DPF is approaching a state where it should be cleaned when a slope of the regression line exceeds a second threshold value that is smaller than the first threshold value.

6. When the slope of the regression line exceeds the second threshold value and at least one of the following additional conditions (1) to (6) is satisfied, the determination unit: (1) The temperature of the exhaust gas from the diesel engine has changed by a first predetermined temperature or more within a first predetermined time. (2) The temperature of the exhaust gas before passing through the DPF is higher than the temperature of the exhaust gas after passing through the DPF, and the temperature difference between the exhaust gas before and after passing through the DPF exceeds a third threshold value. (3) The temperature of the exhaust gas before passing through the DPF is lower than the temperature of the exhaust gas after passing through the DPF, and the temperature difference between the exhaust gas before and after passing through the DPF exceeds a fourth threshold value. (4) The temperature of the exhaust gas before or after passing through the DPF exceeds a fifth threshold value. (5) A diagnostic code is output in the ECU that controls the diesel engine. (6) The period until automatic regeneration of the DPF is performed has been shorter than the previous period for a certain period of time. The determination device according to claim 5 , wherein the determination device determines that the DPF needs to be cleaned.

7. The determination device according to claim 1 , wherein the intake air amount obtaining section and the differential pressure obtaining section obtain the intake air amount and the differential pressure only when an obtaining condition is satisfied.

8. The acquisition conditions are: the diesel engine is not idling; None of automatic regeneration, manual regeneration, and forced regeneration of the DPF has been performed. The temperature of the DPF is equal to or lower than a sixth threshold value. A PTO (Power Take Off) of the vehicle equipped with the diesel engine is not in use. The temperature of the radiator of the vehicle is equal to or greater than a seventh threshold. The determination device according to claim 7 , wherein the determination device is at least one of the above.

9. A method for determining whether a DPF provided in an exhaust path of a diesel engine is in a state that requires cleaning, comprising: an intake air amount acquisition step of acquiring an intake air amount of the diesel engine; a differential pressure acquisition step of acquiring a differential pressure, which is a difference in air pressure between before and after exhaust gas from the diesel engine passes through the DPF; a determination step of determining whether the DPF is in a state that requires cleaning, using a set of the intake air amount and the differential pressure that are simultaneously acquired; and an output step of outputting a signal indicating that the DPF needs to be cleaned, if the determination step determines that the DPF needs to be cleaned.

10. A control program for causing a computer to function as the determination device according to claim 1, the control program causing a computer to function as the determination unit.

11. A computer-readable recording medium on which the control program according to claim 10 is recorded.

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