Diagnostic equipment

Abstract

The present invention provides a diagnostic device that can diagnose the risk of failure for each component. [Solution] The reference number is the number of times a specific amount of stress is repeatedly applied to the target part before it fails. The actual number is the number of times a specific amount of stress is applied to the target part. The damage rate, which is the sum of the ratios of the actual number to the reference number calculated for each amount of stress applied to the target part, is calculated for each vehicle in which the target part has failed. Based on the damage rates calculated for each of the multiple failed vehicles, a histogram is created in which the damage rate is used as a class and the number of failed vehicles is used as a frequency. The diagnostic device diagnoses that if the damage rate of the target vehicle is within the range of the peak band RP, the vehicle is more likely to fail than if the damage rate is less than the lower limit of the peak band RP (step S14).

Description

Technical Field

[0001] The present invention relates to a diagnostic device.

Background Art

[0002] Patent Document 1 describes a diagnostic device. This diagnostic device acquires driving parameters, which are information indicating the driving state of a vehicle, from a plurality of vehicles. The diagnostic device calculates the similarity between the driving parameters of a certain vehicle and the driving parameters of a plurality of other vehicles. The diagnostic device calculates the similarity for all vehicles from which the driving parameters have been acquired.

[0003] When the similarity of the vehicle to be diagnosed is close to the similarity of the vehicle with a failure history, the diagnostic device diagnoses that the target vehicle has a risk of failure.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described above, in the diagnosis based on the similarity with the vehicle in which a failure has occurred, it is not possible to diagnose the risk of failure for each component.

Means for Solving the Problems

[0006] The diagnostic device for solving the above problem is a diagnostic device that diagnoses the likelihood of failure occurring in a target part, which is a component to be diagnosed, due to its individual characteristics at the time of manufacture. The reference count is the number of times a specific amount of stress is repeatedly applied to the target part, measured in advance, before the failure occurs in the target part. The actual count is the number of times the specific amount of stress is applied to the target part in the vehicle, measured based on the vehicle's driving history. Based on the reference count and the actual count, a damage rate is calculated for each vehicle in which the failure has occurred in the target part, which is the sum of the ratio of the actual count to the reference count calculated for each amount of stress applied to the target part in the vehicle. Based on the damage rate calculated for each of the multiple failure vehicles, a histogram is created in which the damage rate is used as a class and the number of failure vehicles is used as a frequency. The diagnostic device comprises a processing circuit and a memory device. The memory device stores information about the histogram. The peak band is the range of the damage rate determined to include the class with the highest frequency in the histogram. The processing circuit determines that if the damage rate in the target vehicle, which is the vehicle being diagnosed, is within the range of the peak band, the likelihood of the failure occurring in the target component in the target vehicle is higher than if the damage rate in the target vehicle is less than the lower limit of the peak band. [Effects of the Invention]

[0007] The diagnostic device can diagnose the risk of failure for each component. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram showing the configuration of a diagnostic system equipped with a diagnostic device according to one embodiment. [Figure 2] Figure 2 is a table showing the engine operating time for different combinations of engine speed and load factor in a vehicle. [Figure 3] Figure 3 shows the histogram used by the diagnostic device in Figure 1 for diagnosis. [Figure 4] Figure 4 is a table showing the surface pressure applied to the bearings installed on the engine, depending on the combination of engine speed and load factor. [Figure 5] Figure 5 is an S / N diagram of the bearings installed in the engine. [Figure 6] Figure 6 is a flowchart showing the processes performed by the diagnostic device shown in Figure 1. [Modes for carrying out the invention]

[0009] An embodiment of the diagnostic device will be described below with reference to Figures 1 to 6. <Configuration of diagnostic system 100> As shown in Figure 1, the diagnostic system 100 consists of a diagnostic device 10 and a target vehicle 20.

[0010] As shown in Figure 1, the diagnostic device 10 comprises a processing circuit 11 and a storage device 12. The processing circuit 11 performs various processes by executing a program stored in the storage device 12. The processing circuit 11 includes a processor. The diagnostic device 10 is capable of diagnosing multiple target vehicles.

[0011] The target vehicles 20 are vehicles that are to be diagnosed by the diagnostic device 10. As shown in Figure 1, in the diagnostic system 100, each target vehicle 20 is equipped with a processing circuit 21, a storage device 22, and a communication device 23. The processing circuit 21 performs various processes by executing a program stored in the storage device 22. The processing circuit 21 includes a processor. Each target vehicle 20 is connected to the diagnostic device 10 so as to be able to communicate through the communication device 23.

[0012] The storage device 22 stores the driving information DD. The driving information DD is information that shows the driving history of the target vehicle 20. Each target vehicle 20 stores its own driving information DD in the storage device 22.

[0013] Figure 2 shows an example of the driving information DD stored in the memory device 22. Figure 2 shows the time the engine was running for each combination of engine speed and engine load percentage. In Figure 2, the engine running time when the engine speed is 2500 rpm and the engine load percentage is 80 percent is t1. In Figure 2, the engine running time when the engine speed is 2500 rpm and the engine load percentage is 120 percent is t2. In Figure 2, the engine running time when the engine speed is 3000 rpm and the engine load percentage is 80 percent is t3. In Figure 2, the engine running time when the engine speed is 3000 rpm and the engine load percentage is 120 percent is t4.

[0014] The information stored by the storage device 22 as driving information DD is not limited to the information shown in Figure 2. For example, the storage device 22 may store the number of times the engine was started or the number of times the brakes were applied suddenly as driving information DD.

[0015] <Overview of diagnosis by diagnostic device 10> The diagnostic device 10 diagnoses the likelihood of a failure occurring in the target component of the target vehicle 20. In this case, the failure diagnosed by the diagnostic device 10 is a failure caused by the individual characteristics of the target component at the time of manufacture.

[0016] In this embodiment, the diagnostic device 10 targets a bearing attached to the crankshaft of the engine of the target vehicle 20. In the bearings installed in the engine, minute foreign matters such as cutting chips may be mixed in at the time of engine manufacture. The diagnostic device 10 diagnoses the likelihood of a failure caused by foreign matters mixed in at the time of engine manufacture in the bearings of the target vehicle 20.

[0017] The diagnostic device 10 executes a diagnosis on the target component based on information regarding a histogram created in advance. FIG. 3 shows the histogram used for diagnosis by the diagnostic device 10.

[0018] As shown in FIG. 3, the histogram uses the damage rate as the class and the number of failed vehicles as the frequency. FIG. 3 shows 17 classes from A to Q. A is the class with the smallest damage rate among A to Q. Q is the class with the largest damage rate among A to Q. A failed vehicle is a vehicle in which the target component has failed. In this embodiment, a failed vehicle is a vehicle in which the engine bearing has failed.

[0019] To create the histogram, the damage rate has been calculated for each of a plurality of failed vehicles. Below, the method for calculating the damage rate will be described. <Method for Calculating Damage Rate> The damage rate is calculated based on a reference number of times and an actual number of times.

[0020] The actual number of times is the number of times a specific amount of stress is applied to the target component of the vehicle. The amount of stress applied to the bearing is the surface pressure value applied to the bearing. That is, in the diagnostic device 10, the actual number of times is the number of times stress is applied to the bearing at a specific surface pressure value.

[0021] Figure 4 shows the surface pressure values ​​of the stress on the bearings installed in the engine, depending on the combination of engine speed and load factor. The surface pressure values ​​shown in Figure 4 were measured in advance to calculate the damage rate.

[0022] In Figure 4, the surface pressure applied to the bearing when the engine speed is 2500 rpm and the engine load is 80 percent is P1. In Figure 4, the surface pressure applied to the bearing when the engine speed is 2500 rpm and the engine load is 120 percent is P2. In Figure 4, the surface pressure applied to the bearing when the engine speed is 3000 rpm and the engine load is 80 percent is P3. In Figure 4, the surface pressure applied to the bearing when the engine speed is 3000 rpm and the engine load is 120 percent is P4.

[0023] The actual number of cycles is measured for each amount of stress. The surface pressure applied to the bearing differs for each combination of engine speed and load factor. In other words, the actual number of cycles is measured for each combination of engine speed and load factor.

[0024] Bearings are subjected to stress each time fuel burns in the cylinder and the crankshaft rotates. In one cylinder, fuel combustion occurs once for every two rotations of the engine's crankshaft.

[0025] In the diagnostic system 100, data is measured for the faulty vehicle, as shown in Figure 2, until the bearing fails. The actual number of cycles can be observed from the engine operating time corresponding to the combination of engine speed and load factor shown in Figure 2. Specifically, the actual number of cycles is calculated using the following formula.

[0026]

number

[0027] In the above formula, the actual number of times stress is applied to the bearing from the nearest cylinder is used. In this way, the diagnostic device 10 can calculate the number of times stress has been applied to the bearing for each surface pressure value by calculating the number of times stress has been applied to the bearing for each combination of engine speed and load factor. The diagnostic device 10 observes the number of times stress has been applied for each surface pressure value calculated in this way as the actual number.

[0028] The baseline number of stresses is the number of times a specific amount of stress is repeatedly applied to a component before it fails. This baseline number is measured in advance to calculate the damage rate.

[0029] Figure 5 is an S / N diagram showing the number of times a bearing is subjected to repeated stress at a specific surface pressure value before it fails. Figure 5 shows the number of times stress is applied before the bearing fails.

[0030] When measuring the data shown in Figure 5, bearings containing foreign matter of a certain size at each surface pressure value were used. For example, when measuring the data shown in Figure 5, bearings containing foreign matter of 0.2 mm in size were used at each surface pressure value.

[0031] Figure 5 shows that when a stress of magnitude P2 is repeatedly applied to the bearing, the bearing fails after N stresses. Figure 5 also shows that when a surface pressure of 100 MPa or less is applied, the bearing does not fail regardless of how many times the stress is applied.

[0032] Figure 5 shows the number of times a bearing with a specific surface pressure value of stress is repeatedly applied to a bearing containing foreign matter before it fails, summarized for each surface pressure value. The diagnostic device 10 uses these number of times for each surface pressure value as reference counts.

[0033] Thus, in the diagnostic system 100, the actual number of cycles and the reference number of cycles are measured for each surface pressure value. The damage rate is the sum of the ratios of the actual number of cycles to the reference number of cycles, calculated for each amount of stress applied to the target parts of the vehicle.

[0034] For example, as shown in Figure 2, the engine operating time t2 is when the engine speed is 2500 rpm and the engine load is 120 percent. The surface pressure value of the stress applied to the engine at an engine speed of 2500 rpm and an engine load of 120 percent is P2. Therefore, by referring to Figures 2 and 4 and using the formula shown in Equation 1, the actual number of cycles when the surface pressure value is P2 can be calculated. Also, as shown in Figure 5, the standard number of cycles when the surface pressure value is P2 is N. Based on the actual number of cycles calculated in this way and the standard number of cycles, the ratio of the actual number of cycles to the standard number of cycles when the surface pressure value is P2 can be calculated.

[0035] On the other hand, as shown in Figure 5, when the surface pressure value is P1, the bearing does not fail, and therefore the reference number of cycles cannot be measured. In the diagnostic system 100, for surface pressure values ​​where the reference number of cycles cannot be measured, the ratio of the actual number of cycles to the reference number of cycles is not calculated.

[0036] In this way, by referring to the data in Figures 2, 4, and 5, the ratio of the actual number of cycles to the reference number of cycles can be calculated for each surface pressure value. Then, by summing up the ratios calculated in this way, the damage rate can be calculated.

[0037] <Histogram Overview> In the diagnostic system 100, a histogram like the one shown in Figure 3 is created based on the damage rate calculated using the method described above. The diagnostic device 10 stores information about the histogram shown in Figure 3 in the storage device 12. The diagnostic device 10 may store information about the histogram it has created, or it may store information about a histogram that has already been created.

[0038] As shown in Figure 3, a peak band RP is defined for each class in the histogram. The peak band RP is the range of damage rates determined to include the class with the highest frequency in the histogram. In Figure 3, the range of classes C to F is the peak band.

[0039] <Processing performed by the diagnostic device 10> Figure 6 shows the sequence of processes performed by the processing circuit 11 of the diagnostic device 10. The processing circuit 11 performs the sequence of processes shown in Figure 6 when it acquires driving information DD from the target vehicle 20. For example, the diagnostic device 10 acquires driving information DD through communication with the target vehicle 20.

[0040] In step S11, the processing circuit 11 calculates the damage rate of the bearings in the target vehicle 20 based on the acquired driving information DD. After calculating the damage rate, the processing circuit 11 proceeds to step S12.

[0041] In step S12, the processing circuit 11 determines whether the damage rate of the target vehicle 20 is within the range of the peak band RP in the histogram. If the processing circuit 11 determines in step S12 that the damage rate of the target vehicle 20 is within the peak range RP (step S12: YES), it proceeds to step S14. In step S14, the processing circuit 11 determines that there is a high risk of the bearings of the target vehicle 20 failing. After that, the processing circuit 11 proceeds to step S15.

[0042] After diagnosing the target vehicle 20, the diagnostic device 10 recommends that the user of the target vehicle 20 inspect the target parts based on the diagnostic results. At this time, the diagnostic device 10 displays an image to the user of the target vehicle 20 indicating that inspection of the target parts is recommended. For example, the diagnostic device 10 displays an image indicating that inspection of the target parts is recommended on the HMI (Human Machine Interface) of the target vehicle 20. The diagnostic device 10 may also display an image indicating that inspection of the target parts is recommended on a mobile information terminal owned by the user of the target vehicle 20.

[0043] The greater the risk of failure in the target component, the higher the urgency of the inspection. There are three types of ways in which the diagnostic device 10 displays images to the user: the first pattern, the second pattern, and the third pattern. The urgency of the inspection increases in the order of the first pattern, the second pattern, and the third pattern, from highest to lowest.

[0044] The diagnostic device 10 recommends the examination more strongly the more urgent the examination is. The diagnostic device 10 changes the content of the message displayed in the image to a stronger recommendation for the examination, depending on the pattern of urgency for the examination. The diagnostic device 10 displays the image more frequently, depending on the pattern of urgency for the examination.

[0045] In step S15, the processing circuit 11 recommends that the user of the target vehicle 20 perform the inspection using the first pattern. Subsequently, the processing circuit 11 completes the series of processes shown in Figure 6.

[0046] If the processing circuit 11 determines in step S12 that the damage rate of the target vehicle 20 is not within the range of the peak band RP (step S12: NO), it proceeds to step S13. In step S13, the processing circuit 11 determines whether or not the damage rate of the target vehicle 20 is below the lower limit of the peak band RP.

[0047] If the processing circuit 11 determines in step S13 that the damage rate of the target vehicle 20 is less than the lower limit of the peak band RP (step S13: YES), it proceeds to step S16.

[0048] If the damage rate in the target vehicle 20 is less than the lower limit of the peak band RP, it can be inferred that the amount of damage accumulated due to stress in the target parts is not large. In step S16, the processing circuit 11 determines that the risk of bearing failure in the target vehicle 20 is moderate. In other words, in step S16, the processing circuit 11 determines that the risk of bearing failure in the target vehicle 20 is lower than in the case of step S14, but higher than in the case of step S18, which will be described later. After that, the processing circuit 11 proceeds to step S17.

[0049] In step S17, the processing circuit 11 recommends that the user of the target vehicle 20 undergo inspection using the second pattern. Subsequently, the processing circuit 11 completes the series of processes shown in Figure 6.

[0050] If the processing circuit 11 determines in step S13 that the damage rate of the target vehicle 20 is not less than the lower limit of the peak band RP (step S13: YES), it proceeds to step S18. In other words, the processing circuit 11 proceeds to step S18 if the damage rate of the target vehicle 20 is greater than the upper limit of the peak band RP.

[0051] If the damage rate in vehicle 20 is greater than the upper limit of the peak band RP, it indicates that a failure did not occur despite the high damage rate. Therefore, it is considered that the influence of the characteristics present at the time of manufacture was small in vehicle 20. More specifically, it is considered that the amount of foreign matter mixed in the bearing was small, and the possibility of failure caused by foreign matter was low.

[0052] In step S18, the processing circuit 11 determines that the risk of bearing failure in the target vehicle 20 is small. In other words, in step S18, the processing circuit 11 determines that the risk of bearing failure in the target vehicle 20 is smaller than in the cases of steps S14 and S16. Subsequently, the processing circuit 11 proceeds to step S19.

[0053] In step S19, the processing circuit 11 recommends that the user of the target vehicle 20 undergo inspection using the third pattern. Subsequently, the processing circuit 11 completes the series of processes shown in Figure 6.

[0054] <Operation of this embodiment> The diagnostic device 10 uses a damage rate calculated based on the number of times stress has been applied to the target part in the target vehicle 20 to diagnose the likelihood of failure of the target part in the target vehicle 20.

[0055] <Effects of this embodiment> (1) The diagnostic device 10 can diagnose whether there is a risk of failure for each component. (2) The processing circuit 11 determines that if the damage rate in the target vehicle 20 is greater than the upper limit of the peak band RP, the likelihood of a failure occurring in the target component in the target vehicle 20 is lower than if the damage rate in the target vehicle 20 is less than the lower limit of the peak band RP.

[0056] If the damage rate exceeds the upper limit of the peak band RP, it is presumed that the influence of the characteristics present at the time of manufacture is small. Therefore, if the damage rate in the target vehicle 20 exceeds the upper limit of the peak band RP, it is considered that the target parts in the target vehicle 20 are less likely to experience failures due to their individual characteristics. The diagnostic device 10 determines that the likelihood of failure is low if the damage rate in the target vehicle 20 exceeds the upper limit of the peak band RP. In this way, the diagnostic device 10 can identify target parts that are less likely to fail during diagnosis.

[0057] (3) If the damage rate in the target vehicle 20 is greater than the upper limit of the peak band RP, the processing circuit 11 will recommend that the user of the target vehicle 20 inspect the target parts less frequently than if the damage rate in the target vehicle 20 is less than the lower limit of the peak band RP.

[0058] The diagnostic device 10 reduces the frequency of recommended inspections when the target vehicle 20 is a vehicle that is less prone to malfunctions. This allows the diagnostic device 10 to appropriately adjust the frequency of recommended inspections according to the characteristics of the individual vehicle.

[0059] (4) The diagnostic device 10 targets the bearing attached to the crankshaft of the engine of the target vehicle 20. The diagnostic device 10 observes the damage rate of the bearing attached to the engine. This allows the diagnostic device 10 to diagnose the likelihood of the bearing failing.

[0060] (5) The amount of stress applied to the bearing is the surface pressure value applied to the bearing. With foreign matter mixed in the bearing, a reference number of times is measured in advance for each surface pressure value. For each combination of engine load and engine rotations per hour, the surface pressure value applied to the bearing is measured in advance. Based on the engine operating time in the vehicle measured for each combination, the number of times stress has been applied to the bearing for each surface pressure value corresponding to the combination is observed as the actual number. The memory device 12 stores information about the histogram created using the reference number and the actual number.

[0061] The diagnostic device 10 observes the surface pressure applied to the bearing. This allows the diagnostic device 10 to diagnose whether or not there is a risk of bearing failure. <Example of changes> This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0062] The manner in which the actual number of times is calculated in the diagnostic system 100 is not limited to the manner shown in Equation 1 above. In the above embodiment, the actual number of times each bearing is subjected to stress at a specific surface pressure value is used. On the other hand, it is also conceivable that the actual number of times any of the multiple bearings in the engine is subjected to stress at a specific surface pressure value is used.

[0063] In engines with multiple cylinders, fuel combustion occurs in at least one of the cylinders each time the engine rotates. Therefore, if we define the actual number of times a specific bearing in the engine is subjected to stress at a particular surface pressure value, we may not need to divide the engine's rotational speed per unit time by two.

[0064] In the above embodiment, as shown in Figure 5, the number of times stress is applied to a single bearing before failure occurs is defined as the reference number. If the actual number of times stress is applied to any of the bearings in the engine at a specific surface pressure value is defined as the reference number, then the reference number is, for example, the number of times the engine rotates before any of the bearings fails.

[0065] In the above embodiment, the diagnostic device 10 calculates the damage rate itself after acquiring driving information DD from the target vehicle 20. Alternatively, the diagnostic device 10 may acquire a previously calculated damage rate from another device instead of calculating the damage rate itself.

[0066] In the above embodiment, the diagnostic device 10 determines that the risk of failure of the target component is lower when the damage rate in the target vehicle 20 is greater than the upper limit of the peak band RP, compared to when the damage rate in the target vehicle 20 is less than the lower limit of the peak band RP. On the other hand, the diagnostic device 10 may determine that the risk is equivalent to when the damage rate in the target vehicle 20 is less than the lower limit of the peak band RP, even when the damage rate in the target vehicle 20 is greater than the upper limit of the peak band RP.

[0067] In the above embodiment, the diagnostic device 10 modifies the mode of recommending inspections according to the urgency of the inspection in the target vehicle 20. The diagnostic device 10 does not have to modify the mode of recommending inspections according to the urgency of the inspection in the target vehicle 20. For example, the diagnostic device 10 may recommend inspecting the target parts at the same frequency as when the damage rate in the target vehicle 20 is less than the lower limit of the peak band RP, even when the damage rate in the target vehicle 20 is greater than the upper limit of the peak band RP.

[0068] In the above embodiment, the diagnostic device 10 targets a bearing attached to the crankshaft of the engine. However, the target parts are not limited to bearings. For example, the diagnostic device 10 may diagnose the level of risk of failure occurring due to low heat treatment accuracy in metal parts whose manufacturing process includes heat treatment, resulting in variations in heat treatment precision. [Explanation of Symbols]

[0069] 10...Diagnostic device, 11...Processing circuit, 12...Storage device, 20...Target vehicle, 21...Processing circuit, 22...Storage device, 23...Communication device, 100...Diagnostic system, DD...Driving information, RP...Peak band

Claims

1. This diagnostic device diagnoses the likelihood of failure occurring in a target component due to its individual characteristics at the time of manufacture. For a vehicle in which the failure has occurred, a damage rate is calculated based on a reference number, which is the number of times a specific amount of stress is repeatedly applied to the target part before the failure occurs, and an actual number, which is the number of times the specific amount of stress is applied to the target part in the vehicle, measured based on the vehicle's driving history. The damage rate is the sum of the ratio of the actual number to the reference number, calculated for each amount of stress applied to the target part in the vehicle. Based on the damage rate calculated for each of the multiple aforementioned malfunctioning vehicles, a histogram is created in which the damage rate is used as a class and the number of malfunctioning vehicles is used as a frequency. It comprises a processing circuit and a memory device. The memory device stores information about the histogram, The processing circuit determines that if the damage rate in the target vehicle, which is the vehicle being diagnosed, falls within the range of the peak band, which is the range of damage rates determined to include the class with the highest frequency in the histogram, then the likelihood of the failure occurring in the target part of the target vehicle is higher than when the damage rate in the target vehicle is less than the lower limit of the peak band. Diagnostic equipment.

2. The processing circuit determines that if the damage rate in the target vehicle is greater than the upper limit of the peak band, the likelihood of the failure occurring in the target part of the target vehicle is lower than if the damage rate in the target vehicle is less than the lower limit of the peak band. The diagnostic device according to claim 1.

3. The processing circuit, when the damage rate in the target vehicle is greater than the upper limit of the peak band, recommends that the user of the target vehicle inspect the target part less frequently than when the damage rate in the target vehicle is less than the lower limit of the peak band. The diagnostic device according to claim 2.

4. The bearing attached to the crankshaft of the engine of the aforementioned vehicle is the aforementioned part. A diagnostic device according to any one of claims 1 to 3.

5. The amount of stress applied to the bearing is the surface pressure applied to the bearing. With foreign matter mixed into the bearing, the reference number of cycles in the bearing has been measured in advance for each surface pressure value. For each combination of engine load and engine rotation speed per unit time in the aforementioned engine, the surface pressure value applied to the bearing is measured in advance. Based on the engine operating time in the vehicle measured for each combination, the number of times the stress was applied to the bearing for each surface pressure value corresponding to the combination is observed as the actual number of times. The storage device stores information about the histogram created using the reference count and the actual count. The diagnostic device according to claim 4.

Images