Deterioration estimation device

Abstract

To estimate a deterioration degree of a vehicle component while suppressing the increase in an amount of data stored in a memory.SOLUTION: In a processing circuit 51 of a control device 50, the stress of a compressor impeller 171 is acquired for each prescribed control cycle. A step of setting a small section and a step of calculating a small section average value being an average value of the maximum value and the minimum value of the stress in the small section and a small section amplitude being an amplitude of the stress in the small section are repeatedly executed. A step of setting a middle section and a step of calculating a middle section average value being an average value of the maximum value and the minimum value of the stress in the middle section and a middle section amplitude being an amplitude of the stress in the middle section are repeatedly executed. A first damage value is calculated on the basis of the small section average value and the small section amplitude. A second damage value is calculated on the basis of the middle section average value and the middle section amplitude. An estimation value of a deterioration degree of the compressor impeller 171 is calculated on the basis of the integrated value of the first damage value and the second damage value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a deterioration estimation device for estimating the degree of deterioration of a vehicle part. [Background technology]

[0002] Patent Document 1 discloses a method for diagnosing a fatigue fault in a turbocharger. In this method, an interval is set. That is, the inflection point at which the rotational speed of the turbocharger becomes equal to or less than a threshold is set as the start point of the interval. The inflection point at which the rotational speed next becomes equal to or less than the threshold is set as the end point of the interval. A fatigue value for the interval is calculated by counting cycles within the interval using the rainflow method. This calculation of the fatigue value is performed each time the interval is set. Then, a fatigue fault in the turbocharger is diagnosed by comparing the cumulative fatigue value with a predetermined limit value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-56762 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above method, the inflection point where the rotational speed at the inflection point falls below the threshold is set as the end point of the section. Therefore, the inflection point continues to be stored in the storage device until the rotational speed falls below the threshold. When the engine continues to operate under high load, the rotational speed does not fall below the threshold easily, so the number of inflection points stored in the storage device becomes very large. Therefore, to implement the above method, a storage device with a relatively large storage capacity is required. [Means for solving the problem]

[0005] A deterioration estimation device for solving the above problem is a device for estimating the degree of deterioration of a vehicle part provided in a vehicle. The deterioration estimation device includes a processing circuit. The processing circuit includes: The stress applied to the vehicle part is Parameters as The method acquires the parameter for each predetermined control cycle and sets a short interval having a length of a first time, and repeatedly calculates a short interval average value which is the average of the maximum and minimum values ​​of the parameter in the short interval, and a short interval amplitude which is the amplitude of the parameter in the short interval, and sets a medium interval whose start point is the time point at which the parameter becomes equal to or greater than a parameter lower limit value and whose end point is the time point at which the parameter becomes less than the parameter lower limit value, and repeatedly calculates a medium interval average value which is the average of the maximum and minimum values ​​of the parameter in the medium interval, and a medium interval amplitude which is the amplitude of the parameter in the medium interval, and calculates a first damage value which is the degree of deterioration of the vehicle part in the short interval based on the short interval average value and the short interval amplitude, calculates a second damage value which is the degree of deterioration of the vehicle part in the medium interval based on the medium interval average value and the medium interval amplitude, and calculates an estimated value of the degree of deterioration of the vehicle part based on an integrated value of the first damage value and the second damage value.

[0006] Oscillating parameters can accelerate the deterioration of vehicle components. Therefore, in the deterioration estimation device, each time a small section is set, a small section average value and a small section amplitude are calculated for that small section. Then, a first damage value is calculated based on the small section average value and the small section amplitude. The first damage value indicates the degree of deterioration of the vehicle part caused by the vibration of the parameter over a relatively short section.

[0007] In the deterioration estimation device, a medium section average value and a medium section amplitude are calculated for each medium section. Then, a second damage value is calculated based on the medium section average value and the medium section amplitude. The second damage value indicates the degree of deterioration of the vehicle part caused by large fluctuations in parameters over a relatively long section.

[0008] In the deterioration estimation device, an estimated value of the degree of deterioration of a vehicle part is calculated by integrating both the first damage value and the second damage value. In this case, the number of data items stored in the memory of the processing circuit in the process of calculating the estimated value can be smaller than when using the rainflow method described above.

[0009] Therefore, the deterioration estimation device can estimate the degree of deterioration of a vehicle part while suppressing an increase in the amount of data stored in memory. When acquiring the parameters, the parameters may be calculated by substituting the detection values ​​of the on-board sensors or correlation values ​​of the detection values ​​into a physical formula. Alternatively, the parameters may be calculated by inputting the detection values ​​or correlation values ​​of the detection values ​​into a trained model that has been subjected to machine learning. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a configuration diagram showing a control device that is an embodiment of a deterioration estimation device, and an internal combustion engine that is an object to be controlled by the control device. [Figure 2] FIG. 2 is a block diagram showing a plurality of processes executed by the control device of FIG. [Figure 3] FIG. 3 is a graph illustrating the details of the small section process among the multiple processes in FIG. [Figure 4] FIG. 4 is a graph illustrating the contents of the intermediate interval process among the plurality of processes in FIG. [Figure 5] FIG. 5 is a graph showing the average stress and stress amplitude of the compressor impeller included in the internal combustion engine of FIG. [Figure 6] FIG. 6 is a modified Goodman diagram showing the mean stress and stress amplitude of the compressor impeller included in the internal combustion engine of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of a deterioration estimation device will be described below with reference to FIGS. 1 illustrates an internal combustion engine 10 and a control device 50 that controls the internal combustion engine 10. In this embodiment, the control device 50 functions as a "deterioration estimation device."

[0012] <Internal combustion engine> The internal combustion engine 10 includes a combustion chamber 11, an intake passage 12, an exhaust passage 13, and an exhaust-driven supercharger 15. Air that has flowed through the intake passage 12 is introduced into the combustion chamber 11. In the combustion chamber 11, an air-fuel mixture containing air and fuel is combusted. Exhaust gas produced by the combustion of the air-fuel mixture is discharged from the combustion chamber 11 to the exhaust passage 13.

[0013] The supercharger 15 has a turbine 16 and a compressor 17. The turbine 16 is provided in the exhaust passage 13. The compressor 17 is provided in a portion upstream of the throttle valve in the intake passage 12. Note that, depending on the type of internal combustion engine, the throttle valve may be provided in a portion upstream of the compressor 17 in the intake passage 12. A compressor impeller 171 of the compressor 17 is connected to a turbine wheel 161 of the turbine 16 via a connecting shaft 18. Therefore, when the turbine wheel 161 rotates due to the flow of exhaust gas flowing through the exhaust passage 13, the compressor impeller 171 rotates in synchronization with the turbine wheel 161. As a result, the air flowing through the intake passage 12 is compressed.

[0014] <Control device> Signals are input to the control device 50 from multiple types of sensors that detect the state of the internal combustion engine 10. The multiple types of sensors include a boost pressure sensor 31 and a flow rate sensor 32. The boost pressure sensor 31 detects the pressure of the intake air pressurized by the compressor impeller 171. The flow rate sensor 32 detects the flow rate of the intake air flowing into the compressor 17. The pressure of the intake air based on the detection value of the boost pressure sensor 31 is referred to as the "boost pressure PTC." The flow rate of the intake air based on the detection value of the flow rate sensor 32 is referred to as the "air flow rate QTC."

[0015] The control device 50 includes a processing circuit 51. For example, the processing circuit 51 is an electronic control device. In this case, the processing circuit 51 includes a CPU 52, a first memory 53, and a second memory 54. The first memory 53 stores a control program executed by the CPU 52. The second memory 54 temporarily stores the calculation results of the CPU 52. The CPU 52 executes the control program in the first memory 53, causing the processing circuit 51 to estimate the degree of deterioration of the components of the internal combustion engine 10. In this embodiment, the processing circuit 51 estimates the degree of deterioration of the compressor impeller 171. Therefore, the compressor impeller 171 corresponds to the "vehicle component" whose degree of deterioration is to be estimated.

[0016] 2 to 4, a plurality of processes executed by the processing circuit 51 to estimate the degree of deterioration of the compressor impeller 171 will be described. As shown in FIG. 2, the processing circuit 51 executes a stress calculation process M11, a small interval process M13, a medium interval process M14, a damage calculation process M15, an estimation process M16, and a diagnosis process M17.

[0017] <Stress calculation processing> In stress calculation processing M11, the processing circuit 51 calculates the stress FST applied to the compressor impeller 171. Repeated fluctuations in the stress applied to the compressor impeller 171 may cause deterioration of the compressor impeller 171. Therefore, the processing circuit 51 calculates the stress FST applied to the compressor impeller 171 as a parameter that may cause deterioration of a vehicle part to progress. The processing circuit 51 executes the stress calculation processing M11 for each predetermined control cycle.

[0018] Specifically, the processing circuit 51 calculates the impeller rotation speed NCI, which is the rotation speed of the compressor impeller 171, based on the boost pressure PTC and the air flow rate QTC. For example, the processing circuit 51 calculates the impeller rotation speed NCI so that the rotation speed increases as the boost pressure PTC increases. The processing circuit 51 calculates the impeller rotation speed NCI so that the rotation speed increases as the air flow rate QTC increases. The processing circuit 51 calculates the centrifugal force FC acting on the compressor impeller 171 based on the impeller rotation speed NCI. At this time, the processing circuit 51 calculates the centrifugal force FC by substituting the impeller rotation speed NCI into a well-known physical formula. Then, the processing circuit 51 calculates the stress FST so that the value increases as the centrifugal force FC increases.

[0019] <Processing for small sections> 3, in the sub-section process M13, the processing circuit 51 sets the sub-section SCa so that the length of time is equal to the first time TM1. The processing circuit 51 repeatedly sets the sub-section SCa.

[0020] Furthermore, in the sub-section process M13, the processing circuit 51 calculates a sub-section average value FSTAvA and a sub-section amplitude FSTAmA based on the transition of the stress FST in the sub-section SCa. Each time a sub-section SCa is set, the processing circuit 51 calculates the sub-section average value FSTAvA and the sub-section amplitude FSTAmA based on the transition of the stress FST in the sub-section SCa. Specifically, the processing circuit 51 acquires the maximum value FSTmaxA and the minimum value FSTminA of the stress FST in the sub-section SCa. The processing circuit 51 calculates the average of the maximum value FSTmaxA and the minimum value FSTminA as the sub-section average value FSTAvA. For example, the processing circuit 51 calculates the value obtained by dividing the sum of the maximum value FSTmaxA and the minimum value FSTminA by 2 as the sub-section average value FSTAvA. The processing circuit 51 calculates the sub-section amplitude FSTAmA, which is the amplitude of the stress FST in the sub-section SCa, based on the maximum value FSTmaxA and the minimum value FSTminA. For example, the processing circuit 51 calculates the difference between the maximum value FSTmaxA and the minimum value FSTminA divided by 2 as the short interval amplitude FSTAmA.

[0021] <Mid-section processing> The processing circuit 51 sets the medium section SCb in the medium section process M14. That is, as shown in FIG. 4, the processing circuit 51 sets the start point of the medium section SCb to the time when the stress FST becomes equal to or greater than the stress lower limit value FSTth. The processing circuit 51 sets the end point of the medium section SCb to the time when the stress FST becomes less than the stress lower limit value FSTth after the time elapsed from the start point of the medium section SCb exceeds the second time TM2, which is longer than the first time TM1. This allows the processing circuit 51 to set the medium section SCb to be longer in time than the short section SCa. The stress lower limit value FSTth is set as a criterion for determining whether the stress FST has become sufficiently small. In this embodiment, the stress FST corresponds to a parameter, and therefore the stress lower limit value FSTth corresponds to the "parameter lower limit value."

[0022] Furthermore, in the medium section process M14, the processing circuit 51 calculates a medium section average value FSTAvB and a medium section amplitude FSTAmB based on the transition of the stress FST in the medium section SCb. Each time a medium section SCb is set, the processing circuit 51 calculates the medium section average value FSTAvB and the medium section amplitude FSTAmB based on the transition of the stress FST in the medium section SCb. Specifically, the processing circuit 51 acquires the maximum value FSTmaxB and the minimum value FSTminB of the stress FST in the medium section SCb. The processing circuit 51 calculates the average of the maximum value FSTmaxB and the minimum value FSTminB as the medium section average value FSTAvB. For example, the processing circuit 51 calculates the value obtained by dividing the sum of the maximum value FSTmaxB and the minimum value FSTminB by 2 as the medium section average value FSTAvB. The processing circuit 51 calculates the medium section amplitude FSTAmB, which is the amplitude of the stress FST in the medium section SCb, based on the maximum value FSTmaxB and the minimum value FSTminB. For example, the processing circuit 51 calculates the difference between the maximum value FSTmaxB and the minimum value FSTminB divided by 2 as the intermediate section amplitude FSTAmB.

[0023] <Damage calculation process> Returning to FIG. 2, in the damage calculation process M15, the processing circuit 51 calculates a first damage value DMA, which is the degree of deterioration of the compressor impeller 171 in the sub-section SCa. That is, the processing circuit 51 calculates the first damage value DMA for the sub-section SCa, for which the sub-section average value FSTAvA and the sub-section amplitude FSTAmA have been calculated, based on the sub-section average value FSTAvA and the sub-section amplitude FSTAmA. The processing circuit 51 executes the damage calculation process M15 to calculate the first damage value DMA each time the sub-section average value FSTAvA and the sub-section amplitude FSTAmA are calculated in the sub-section process M13. The first damage value DMA can also be said to be a value corresponding to the degree of deterioration of the compressor impeller 171 caused by the short-period vibration of the stress FST in the sub-section SCa.

[0024] Furthermore, in the damage calculation process M15, the processing circuit 51 calculates a second damage value DMB, which is the degree of deterioration of the compressor impeller 171 in the medium section SCb. That is, the processing circuit 51 calculates the second damage value DMB for the medium section SCb, for which the medium section average value FSTAvB and medium section amplitude FSTAmB have been calculated, based on the medium section average value FSTAvB and medium section amplitude FSTAmB. The processing circuit 51 executes the damage calculation process M15 to calculate the second damage value DMB each time the medium section average value FSTAvB and medium section amplitude FSTAmB are calculated in the medium section process M14. The second damage value DMB can also be said to be a value corresponding to the degree of deterioration of the compressor impeller 171 caused by the long-period vibration of the stress FST in the medium section SCb.

[0025] The damage calculation process M15 will be described in detail with reference to Figures 5 and 6. Figure 5 is a graph with the horizontal axis representing the average stress and the vertical axis representing the stress amplitude. In Figure 5, the black circles represent the small-section average value FSTAvA and the small-section amplitude FSTAmA in the small section SCa. The black triangles represent the medium-section average value FSTAvB and the medium-section amplitude FSTAmB in the medium section SCb.

[0026] 5, the processing circuit 51 plots points representing the short interval average value FSTAvA and the short interval amplitude FSTAmA calculated in the short interval process M13. The processing circuit 51 also plots points representing the medium interval average value FSTAvB and the medium interval amplitude FSTAmB calculated in the medium interval process M14.

[0027] 5 also shows a comparative example in which the mean stress and stress amplitude are calculated by the rainflow method. The points representing the mean stress and stress amplitude calculated by the rainflow method are indicated by open squares. As is clear from FIG. 5, the points representing the mean stress and stress amplitude obtained in this embodiment are distributed in the same region as the points representing the mean stress and stress amplitude calculated by the rainflow method.

[0028] FIG. 6 is a modified Goodman diagram created based on the points plotted on the graph shown in FIG. 5. The straight line in FIG. 6 is the modified Goodman line Lg. Then, as indicated by the dashed arrow in FIG. 6, the processing circuit 51 converts the stress amplitudes shown by the plots on the graph so that the average stress becomes 0 (zero). The converted stress amplitude is called the "converted stress amplitude."

[0029] Next, the processing circuit 51 plots the multiple converted stress amplitudes on an SN diagram. Then, the processing circuit 51 converts the multiple converted stress amplitudes into damage values ​​using the modified Miner's rule. At this time, the value obtained by converting the converted stress amplitude converted from the small interval amplitude FSTAmA into a damage value corresponds to the "first damage value DMA." Also, the value obtained by converting the converted stress amplitude converted from the medium interval amplitude FSTAmB into a damage value corresponds to the "second damage value DMB."

[0030] <Estimation process> In estimation process M16, the processing circuit 51 calculates, based on the first damage value DMA and the second damage value DMB, a deterioration estimation value DGE that is an estimate of the deterioration degree of the compressor impeller 171. Specifically, the processing circuit 51 calculates the sum of the integrated value of the first damage value DMA and the integrated value of the second damage value DMB as the deterioration estimation value DGE.

[0031] <Diagnosis processing> In diagnostic processing M17, the processing circuit 51 compares the deterioration estimation value DGE with a predetermined deterioration determination value DGEth. The deterioration determination value DGEth is a criterion for determining whether maintenance of the compressor impeller 171 is necessary. If the deterioration estimation value DGE is equal to or greater than the deterioration determination value DGEth, the processing circuit 51 diagnoses that maintenance of the compressor impeller 171 is necessary.

[0032] <Action and effect> In the control device 50, each time a sub-section SCa is set, a sub-section average value FSTAvA and a sub-section amplitude FSTAmA in the sub-section SCa are calculated, and a first damage value DMA is calculated based on the sub-section average value FSTAvA and the sub-section amplitude FSTAmA.

[0033] In the control device 50, each time a medium section SCb is set, a medium section average value FSTAvB and a medium section amplitude FSTAmB for the medium section SCb are calculated. Then, a second damage value DMB is calculated based on the medium section average value FSTAvB and the medium section amplitude FSTAmB.

[0034] The control device 50 calculates the degradation estimate value DGE by integrating both the first damage value DMA and the second damage value DMB. When calculating the degradation estimate DGE using the above method, the processing circuit 51 only needs to store the maximum value FSTmaxA and the minimum value FSTminA of the multiple stresses FST calculated in a certain subsection SCa in the second memory 54. Furthermore, when the processing circuit 51 calculates the subsection average value FSTAvA and the subsection amplitude FSTAmA using the stored maximum value FSTmaxA and minimum value FSTminA, it can erase the maximum value FSTmaxA and minimum value FSTminA from the second memory 54.

[0035] Similarly, the processing circuit 51 is only required to store, in the second memory 54, the maximum value FSTmaxB and the minimum value FSTminB of the multiple stresses FST calculated during a certain medium section SCb. Furthermore, after calculating the medium section average value FSTAvB and the medium section amplitude FSTAmB using the stored maximum value FSTmaxB and minimum value FSTminB, the processing circuit 51 can erase the maximum value FSTmaxB and minimum value FSTminB from the second memory 54.

[0036] Therefore, compared to the conventional technology that requires the rotation speed inflection points to be stored in memory until the interval can be set, this embodiment can reduce the amount of data to be temporarily stored in the second memory 54. Therefore, this embodiment can estimate the degree of deterioration of the compressor impeller 171 while suppressing an increase in the amount of data to be stored in the second memory 54.

[0037] In this embodiment, the following effects can be further obtained. (1) Consider a case where the medium section SCb is divided only by the length of time, as in the case of the small section SCa. In this case, if the internal combustion engine 10 is operated in such a way that the stress FST does not decrease easily due to, for example, the compressor impeller 171 continuing to rotate at high speed for a long period of time, it may be impossible to calculate the damage value caused by the gradual oscillation of the stress FST.

[0038] In this embodiment, the end point of the intermediate section SCb is set to the point where the stress FST becomes less than the stress lower limit value FSTth. As a result, even if the internal combustion engine 10 is operated in such a way that the stress FST does not decrease easily as described above, the damage value caused by the gradual change in the stress FST can be calculated as the second damage value DMB.

[0039] (2) In this embodiment, the length of time of the medium section SCb can be made longer than the length of time of the small section SCa. As a result, the small section process M13 can obtain the maximum stress value FSTmaxA and the minimum stress value FSTminA by monitoring short-term vibrations of the stress FST. Meanwhile, the medium section process M14 can obtain the maximum stress value FSTmaxB and the minimum stress value FSTminB by monitoring long-term vibrations of the stress FST. As a result, the degree of deterioration of the compressor impeller 171 caused by short-term vibrations of the stress FST can be calculated as the first damage value DMA. Furthermore, the degree of deterioration of the compressor impeller 171 caused by long-term vibrations of the stress FST can be calculated as the second damage value DMB.

[0040] <Example of change> 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.

[0041] The control device 50 may be embodied as a control device that estimates the degree of deterioration of a vehicle part other than the compressor impeller 171. For example, the other vehicle part may be another component of the internal combustion engine 10, such as a throttle valve. Furthermore, the other vehicle part does not have to be a component of the internal combustion engine 10.

[0042] The second time TM2 may be the same as the first time TM1. Regardless of whether the time elapsed from the start point of the intermediate section SCb is equal to or greater than the first time TM1, the end point of the intermediate section SCb may be set to the time when the stress FST becomes less than the stress lower limit value FSTth.

[0043] If the turbocharger 15 is equipped with a sensor that detects the rotation speed of the compressor impeller 171, the processing circuit 51 may calculate the impeller rotation speed NCI based on the detection value of the sensor.

[0044] The control device 50 may acquire values ​​other than stress as parameters. Examples of parameters other than stress include temperature, humidity, and pH. The control device 50 may calculate the stress FST using a trained model that has been subjected to machine learning. By using the trained model that uses the boost pressure PTC and the air flow rate QTC as input variables, the control device 50 can calculate a value corresponding to the boost pressure PTC and the air flow rate QTC as the stress FST.

[0045] When determining the first time TM1, which is the length of time of the subsection SCa, the first time TM1 may be determined using a trained model. When determining the stress lower limit value FSTth, the stress lower limit value FSTth may be determined using a trained model.

[0046] The processing circuit 51 is not limited to a circuit having a CPU and ROM and executing software processing. In other words, the processing circuit 51 may have any one of the following configurations (a), (b), and (c):

[0047] (a) The processing circuit 51 includes one or more processors that execute various processes according to a computer program. The processor includes a CPU and memory such as RAM and ROM. The memory stores program code or instructions configured to cause the CPU to execute processes. The memory, i.e., computer-readable medium, includes any available medium that can be accessed by a general-purpose or special-purpose computer.

[0048] (b) The processing circuit 51 includes one or more dedicated hardware circuits that perform various processes. Examples of dedicated hardware circuits include application-specific integrated circuits (ASICs) or FPGAs. ASIC stands for "Application Specific Integrated Circuit," and FPGA stands for "Field Programmable Gate Array."

[0049] (c) The processing circuitry 51 includes a processor that executes some of the various processes in accordance with a computer program, and dedicated hardware circuits that execute the remaining processes of the various processes. [Explanation of symbols]

[0050] 10...internal combustion engine, 15...supercharger, 161...turbine wheel, 171...compressor impeller, 18...connecting shaft, 50...control device, 51...processing circuit, 52...CPU, 53...first memory, 54...second memory.

Claims

1. A deterioration estimation device that estimates a degree of deterioration of a vehicle part provided in a vehicle, processing circuitry; The processing circuitry acquiring a stress applied to the vehicle component as a parameter for each predetermined control cycle; repeatedly setting a small interval so that the length of time is a first time, and calculating a small interval average value, which is an average value of the maximum value and the minimum value of the parameter in the small interval, and a small interval amplitude, which is an amplitude of the parameter in the small interval; repeatedly setting a medium section starting from the point when the parameter becomes equal to or greater than a parameter lower limit value and ending from the point when the parameter becomes less than the parameter lower limit value, and calculating a medium section average value which is an average value of the maximum and minimum values ​​of the parameter in the medium section, and a medium section amplitude which is an amplitude of the parameter in the medium section; calculating a first damage value, which is a degree of deterioration of the vehicle component in the small section, based on the small section average value and the small section amplitude; calculating a second damage value, which is a degree of deterioration of the vehicle component in the middle section, based on the middle section average value and the middle section amplitude; Calculating an estimated value of the degree of deterioration of the vehicle part based on an integrated value of the first damage value and the second damage value. Deterioration estimation device.

2. When setting the medium interval, the processing circuit sets the end point of the medium interval to a time point when the parameter becomes less than the parameter lower limit value while the elapsed time from the start point is longer than the first time. The deterioration estimation device according to claim 1 .

3. When setting the medium interval, the processing circuit sets the end point of the medium interval to a time point when the parameter becomes less than the parameter lower limit value in a state where the elapsed time from the start point exceeds a second time that is longer than the first time. The deterioration estimation device according to claim 2 .

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