Method for evaluating remaining life of compressor impeller

Abstract

This invention provides a method for evaluating the remaining life of a compressor impeller in a turbocharger, comprising: a speed acquisition step for acquiring the speed of the turbocharger; a stress calculation step for calculating the stress generated in the compressor impeller from the speed of the turbocharger acquired in the speed acquisition step; an outlet temperature acquisition step for acquiring the outlet temperature of the compressor impeller; a metal temperature calculation step for calculating the metal temperature of the compressor impeller from the outlet temperature of the compressor impeller acquired in the outlet temperature acquisition step; and a remaining life evaluation step for evaluating the remaining life of the compressor impeller by utilizing the correlation between the pre-acquired stress, metal temperature, and life of the compressor impeller, and from the stress calculated in the stress calculation step and the metal temperature calculated in the metal temperature calculation step.

Description

Technical Field

[0001] This invention relates to a method for evaluating the remaining life of a compressor impeller in a turbocharger. This application claims priority based on Japanese Patent Application No. 2021-058030 filed with the Japan Patent Office on March 30, 2021 and Japanese Patent Application No. 2021-195817 filed with the Japan Patent Office on December 2, 2021, the contents of which are incorporated herein by reference. Background Technology

[0002] Previously, it was impossible to accurately determine the lifespan of the compressor impeller in the turbocharger, so the compressor impeller was replaced based on a pre-set replacement interval. Therefore, when the replacement interval was reached, the compressor impeller was replaced even if there was still some life left in its life.

[0003] Therefore, if the lifespan of the compressor impeller cannot be accurately determined, the appropriate replacement period cannot be identified, leading to the inability to utilize the compressor impeller to its full potential. To determine the appropriate replacement period for the compressor impeller, it is desirable to accurately assess its remaining lifespan. Previous technical documents Patent documents

[0004] Patent Document 1: Patent No. 4589751 Summary of the Invention The technical problem to be solved by the invention

[0005] As mentioned above, since the lifespan of the compressor impeller cannot be accurately determined, there is a problem that the compressor impeller cannot be used to its full potential.

[0006] Furthermore, several methods for evaluating the remaining life of compressor impellers have been proposed to date, but none have been put into practical use. For example, Patent Document 1 discloses a turbocharger life determination device that includes a creep monitoring algorithm for monitoring the creep of compressor impellers. This creep monitoring algorithm monitors creep by monitoring the amount of time taken under different combinations of the detected compressor inlet temperature and the calculated compressor pressure ratio. Among these combinations, a creep score representing the stress on the compressor impellers generated by the specific combination is included. The product of the time taken under the specific combination and the creep score becomes the creep stress damage generated in the specific combination, and the total creep stress damage is the monitored creep.

[0007] In view of the above, at least one embodiment of the present invention aims to provide a method for evaluating the remaining life of a compressor impeller by utilizing operating data related to the turbocharger, which can accurately evaluate the remaining life of the compressor impeller. means for solving technical problems

[0008] One embodiment of the present invention relates to a method for evaluating the remaining life of a compressor impeller, which is a method for evaluating the remaining life of a compressor impeller in a booster, comprising: The speed acquisition step involves acquiring the speed of the turbocharger. The stress calculation step involves calculating the stress generated in the compressor impeller from the speed of the booster obtained in the speed acquisition step. The outlet temperature acquisition step involves acquiring the outlet temperature of the compressor impeller. The metal temperature calculation step involves calculating the metal temperature of the compressor impeller from the outlet temperature of the compressor impeller obtained in the outlet temperature acquisition step; and The remaining life evaluation step utilizes the pre-obtained correlation between stress, metal temperature, and life in the compressor impeller to evaluate the remaining life of the compressor impeller based on the stress calculated in the stress calculation step and the metal temperature calculated in the metal temperature calculation step. Invention Effects

[0009] According to at least one embodiment of the present invention, a method for evaluating the remaining life of a compressor impeller is provided, which can accurately evaluate the remaining life of a compressor impeller by utilizing operating data related to the booster. Attached Figure Description

[0010] Figure 1 This is a schematic structural diagram of an engine system that is equipped with a compressor impeller, which is the object of the evaluation method for evaluating the remaining life of a compressor impeller according to an embodiment of the present invention. Figure 2 This is a flowchart of a method for evaluating the remaining life of a compressor impeller according to an embodiment of the present invention. Figure 3 It is an explanatory diagram used to illustrate the relationship between stress in the compressor impeller and the Larssen-Miller parameters. Figure 4 This is a flowchart of the remaining useful life assessment step in one embodiment of the present invention. Figure 5 This is a flowchart of the remaining useful life assessment step in one embodiment of the present invention. Figure 6 This is an explanatory diagram used to illustrate the calculation method for the degree of cumulative damage. Figure 7 This is a flowchart of the speed acquisition step in one embodiment of the present invention. Figure 8This is an explanatory diagram illustrating a correction method for the remaining life of a compressor impeller, showing the shift of the remaining life of the compressor impeller relative to the actual actuation time. Figure 9 This is a graph showing the correlation between the grain size of the material structure on the surface of the compressor impeller and the remaining life of the compressor impeller (grain size correlation information). Figure 10 It is a graph showing the relationship between the strain of the compressor impeller and the remaining life of the compressor impeller (strain correlation information). Figure 11 This is a graph showing the correlation between the hardness of the compressor impeller and the remaining life of the compressor impeller (hardness correlation information). Figure 12 This is a graph showing the correlation between the thickness of the oxide film formed on the surface of the compressor impeller and the remaining life of the compressor impeller (film thickness correlation information). Figure 13 It is a graph showing the relationship between the resistance of the compressor impeller and the remaining life of the compressor impeller (resistance correlation information). Figure 14 It is a graph showing the correlation between the size of internal defects in the compressor impeller and the remaining life of the compressor impeller (internal defect size correlation information). Detailed Implementation

[0011] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc., of the constituent components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples. For example, expressions such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" that indicate relative or absolute configuration not only indicate such configuration in a strict sense, but also indicate a state of relative displacement by angle or distance with tolerance or to the extent that the same function can be obtained. For example, expressions such as "same," "equal," and "homogeneous" that indicate that things are in an equal state not only indicate that they are the same in a strict sense, but also that there are differences in the degree to which they can achieve the same function. For example, the description of shapes such as quadrilaterals or cylinders not only refers to quadrilaterals or cylinders in a strict geometric sense, but also includes shapes with concave or convex parts or chamfers within the range where the same effect can be obtained. On the other hand, expressions such as "possessing," "including," or "having" a constituent element are not exclusive expressions that exclude the existence of other constituent elements. In addition, sometimes the same symbols are used to label the same structures and the explanation is omitted.

[0012] Figure 1 This is a schematic structural diagram representing the structure of an engine system equipped with a compressor impeller, which is the object of the remaining life evaluation method according to one embodiment of the present invention. The remaining life evaluation method 1 for the compressor impeller according to several embodiments of the present invention is a method for evaluating the remaining life of a compressor impeller 4 included in a turbocharger 3. The turbocharger 3 is equipped with, as... Figure 1 The engine system 2 shown has an engine 5.

[0013] (Engine system) like Figure 1 As shown, the engine system 2 includes: an engine (engine body) 5, which generates power by burning fuel inside; a combustion gas supply line 6, for compressing and supplying combustion gas (e.g., air) to the engine 5; a turbocharger 3, having a compressor impeller 4 disposed in the combustion gas supply line 6; and an intercooler 7, disposed downstream of the compressor impeller 4 in the combustion gas supply line 6. The intercooler 7 is composed of a heat exchanger configured to cool the combustion gas passing through the intercooler 7.

[0014] In the illustrated implementation, such as Figure 1 As shown, the engine system 2 includes: an exhaust pipe 8 for guiding exhaust gas discharged from the engine 5; a fuel injection valve 9 configured to inject fuel into the engine 5; and a control device 11. The control device 11 consists of an engine control unit for controlling the operation of various devices in the engine system 2 (such as the engine 5 or the fuel injection valve 9).

[0015] Engine 5 includes: at least one cylinder 51; and at least one piston 52, housed within the at least one cylinder 51 in a manner capable of reciprocating axially. Engine 5 internally has a combustion chamber 53 divided by the cylinder 51 and the piston 52. Combustion chamber 53 is connected downstream of intercooler 7, above combustion gas supply line 6, in a manner allowing gas to flow through. Combustion gas supply line 6 is a flow path for guiding combustion gas from compressor 32 to combustion chamber 53. Combustion chamber 53 is connected to exhaust pipe 8, in a manner allowing gas to flow through. Exhaust pipe 8 is a flow path for allowing exhaust gas discharged from combustion chamber 53 to flow into turbine 33.

[0016] Fuel injected from fuel injection valve 9 into combustion chamber 53 or combustion gas supply line 6 mixes with combustion gas supplied to combustion chamber 53 via combustion gas supply line 6, and then burns within combustion chamber 53. Exhaust gas from combustion in combustion chamber 53 is discharged to the outside of engine system 2 via exhaust pipe 8.

[0017] (Supercharger) In the illustrated embodiment, the turbocharger 3 includes: a turbine 33 driven by energy from exhaust gas discharged from the engine 5; a compressor 32 for compressing combustion gases (e.g., air) supplied to the engine 5; and a rotating shaft 31. The compressor 32 includes: a compressor impeller 4 disposed in the aforementioned combustion gas supply line 6; and a compressor housing 34 rotatably housing the compressor impeller 4. The compressor impeller 4 is mechanically connected to one side of the rotating shaft 31. The turbine 33 includes turbine blades 35 disposed in the aforementioned exhaust gas discharge line 8 and a turbine housing 36 rotatably housing the turbine blades 35. The turbine blades 35 are mechanically connected to the other side of the rotating shaft 31.

[0018] Combustion gas passing through the compressor impeller 4 of compressor 32 is guided to the combustion chamber 53 of engine 5 via combustion gas supply line 6, thus supplying combustion in combustion chamber 53. Exhaust gas generated from combustion in combustion chamber 53 is guided to turbine blades 35 of turbine 33 via exhaust pipe 8. The turbocharger 3 is configured to rotate the turbine blades 35 using the energy from the exhaust gas discharged from engine 5. The compressor impeller 4 is mechanically connected to the turbine blades 35 via rotating shaft 31, and therefore rotates in conjunction with the rotation of the turbine blades 35. The turbocharger 3 is configured to compress the combustion gas passing through the compressor impeller 4 by rotating the compressor impeller 4, increasing the density of the combustion gas before delivering it to engine 5.

[0019] (Measurement equipment mounted on the engine system) In engine system 2, the following measurements are typically performed: the inlet pressure Ps of compressor impeller 4, the pressure Pd of the combustion gas (actuating fluid of compressor impeller 4) downstream of the intercooler 7 of combustion gas supply line 6, the inlet temperature Ts of compressor impeller 4, the temperature Td of the combustion gas (actuating fluid of compressor impeller 4) downstream of the intercooler 7 of combustion gas supply line 6, and the rotational speed N of turbocharger 3. Here, the inlet pressure Ps of compressor impeller 4 is the pressure of the combustion gas (actuating fluid of compressor impeller 4) upstream of compressor impeller 4 in combustion gas supply line 6. The inlet temperature Ts of compressor impeller 4 is the temperature of the combustion gas (actuating fluid of compressor impeller 4) upstream of compressor impeller 4 in combustion gas supply line 6.

[0020] like Figure 1As shown, the engine system 2 includes: a first pressure measuring device (in the example shown, a pressure sensor) 21 configured to measure the inlet pressure Ps of the compressor impeller 4; a second pressure measuring device (in the example shown, a pressure sensor) 22 configured to measure the pressure Pd of the actuating fluid of the compressor impeller 4; a first temperature measuring device (in the example shown, a temperature sensor) 23 configured to measure the inlet temperature Ts of the compressor impeller 4; a second temperature measuring device (in the example shown, a temperature sensor) 24 configured to measure the temperature Td of the actuating fluid of the compressor impeller 4; and a first speed measuring device (in the example shown, a speed sensor) 25 configured to measure the speed N of the turbocharger 3.

[0021] The first pressure measuring device 21, the second pressure measuring device 22, the first temperature measuring device 23, the second temperature measuring device 24, and the first speed measuring device 25 respectively send the measurement results to the control device 11.

[0022] (Methods for evaluating the remaining life of compressor impellers) Figure 2 This is a flowchart of a method for evaluating the remaining life of a compressor impeller according to an embodiment of the present invention. like Figure 2 As shown, the compressor impeller remaining life evaluation method 1 according to several embodiments includes a speed acquisition step S1, a stress calculation step S2, an outlet temperature acquisition step S3, a metal temperature calculation step S4, and a remaining life evaluation step S5. In the illustrated embodiment, the steps in the remaining life evaluation method 1 (stress calculation step S2, metal temperature calculation step S4, remaining life evaluation step S5, etc.) are performed by a control device 11. In other words, the control device 11 is configured to execute the stress calculation step S2 or the metal temperature calculation step S4 and the remaining life evaluation step S5, and perform these steps. Furthermore, the steps in the remaining life evaluation method 1 can be performed by a device or equipment other than the control device 11, or they can be performed manually.

[0023] In one embodiment, the remaining life evaluation device, which is a device different from the control device 11, is configured to perform several steps in the remaining life evaluation method 1 (stress calculation step S2, metal temperature calculation step S4, remaining life evaluation step S5, etc.) in place of the control device 11, and perform the aforementioned steps. Measurement data from the engine system 2 (the respective measurement results of the first pressure measuring device 21, the second pressure measuring device 22, the first temperature measuring device 23, the second temperature measuring device 24, and the first speed measuring device 25) are sent to the remaining life evaluation device. The remaining life evaluation device can be located at a remote location away from the control device 11. Specifically, when the engine system 2, including the control device 11, is installed on a ship, the remaining life evaluation device can be located at the location where the control device 11 is installed on the ship, or it can be located at a location different from the location where the control device 11 is installed on the ship. Furthermore, the remaining life evaluation device can also be located in a land-based facility far from the ship. According to the remaining life evaluation device, the remaining life of the compressor impeller 4 can be evaluated even at a remote location far from the engine system 2, including the control device 11.

[0024] In the speed acquisition step S1, the speed N of the turbocharger 3 is acquired. In the illustrated embodiment, in the speed acquisition step S1, the measured value of the speed of the turbocharger 3 measured by the first speed measuring device 25 is acquired as the speed N of the turbocharger 3.

[0025] In stress calculation step S2, the stress (centrifugal stress) σ generated in the compressor impeller 4 is calculated from the rotational speed N of the booster 3 obtained in step S1. Specifically, before stress calculation step S2, first correlation information R1, representing the correlation between the stress σ generated in the compressor impeller 4 and the rotational speed N of the booster 3, is obtained. In stress calculation step S2, the stress σ is obtained from the rotational speed N based on the pre-obtained first correlation information R1.

[0026] The first correlation information R1 represents the correspondence between the stress σ generated in the compressor impeller 4 and the rotational speed N of the booster 3. When the rotational speed N is used as input information, it is sufficient to obtain the stress σ corresponding to the input rotational speed N as output information. The first correlation information R1 includes lists or tables, mappings, functions, machine learning models, etc., that represent the correspondence between the above input information and the above output information. The first correlation information R1 can be created based on steady-state test data, or it can be created based on past performance values ​​or experimental values, numerical analysis results, etc., other than steady-state test data.

[0027] The stress σ generated in the compressor impeller 4 is proportional to the square of the rotational speed N of the booster 3. Therefore, the higher the rotational speed N, the higher the stress σ. Thus, it can be said that there is a correlation between stress σ and rotational speed N. The first correlation information R1 includes the aforementioned correlation between stress σ and rotational speed N.

[0028] In the outlet temperature acquisition step S3, the outlet temperature Te of the compressor impeller 4 is acquired. The outlet temperature Te of the compressor impeller 4 is the temperature of the combustion gas (the actuating fluid of the compressor impeller 4) located downstream of the compressor impeller 4 in the combustion gas supply line 6 and upstream of the intercooler 7. Since the combustion gas is cooled by the intercooler 7, the temperature Td of the combustion gas located downstream of the intercooler 7 is lower than the outlet temperature Te of the compressor impeller 4.

[0029] In the illustrated embodiment, in the outlet temperature acquisition step S3, the temperature obtained by adding the temperature difference ΔT generated by the intercooler 7 to the temperature Td measured by the second temperature measuring device 24 is acquired as the outlet temperature Te. The temperature difference ΔT is preset based on the specifications of the intercooler 7 between the outlet temperature acquisition steps S3.

[0030] In the metal temperature calculation step S4, the metal temperature Tm of the compressor impeller 4 is calculated from the outlet temperature Te of the compressor impeller 4 obtained in step S3. Specifically, before the metal temperature calculation step S4, second correlation information R2, representing the correlation between the outlet temperature Te and the metal temperature Tm, is obtained. In the metal temperature calculation step S4, the metal temperature Tm is calculated from the outlet temperature Te based on the pre-obtained second correlation information R2.

[0031] The second correlation information R2 represents the correspondence between the outlet temperature Te of the compressor impeller 4 and the metal temperature Tm of the compressor impeller 4. When the outlet temperature Te is used as input information, the metal temperature Tm corresponding to the outlet temperature Te as input information is obtained as output information. The second correlation information R2 includes lists or tables, mappings, functions, machine learning models, etc., representing the correspondence between the above input information and the above output information. The second correlation information R2 can be generated based on steady-state test data, or it can be generated based on past performance values ​​or experimental values, numerical analysis results, etc., other than steady-state test data.

[0032] By compressing the combustion gas using the compressor impeller 4, the outlet temperature Te of the compressor impeller 4 increases due to the temperature rise associated with the compression of the combustion gas. Furthermore, the metal temperature Tm of the compressor impeller 4 increases due to the input heat from the compressed combustion gas. Therefore, the higher the outlet temperature Te, the higher the metal temperature Tm. As can be seen above, there is a correlation between the outlet temperature Te and the metal temperature Tm. The second correlation information R2 includes the aforementioned correlation between the outlet temperature Te and the metal temperature Tm.

[0033] In the remaining life evaluation step S5, the stress σ, metal temperature Tm and life of the compressor impeller 4 are evaluated by using the correlation between the stress σ calculated in the stress calculation step S2, the metal temperature Tm calculated in the metal temperature calculation step S4, and the remaining life of the compressor impeller 4.

[0034] Based on the history of the stress σ or metal temperature Tm in the compressor impeller 4 up to the current moment, damage (creep damage, etc.) occurs and develops in the compressor impeller 4. According to the remaining life evaluation method 1 for the compressor impeller, in the remaining life evaluation step S5, by utilizing the correlation between the stress σ, metal temperature Tm, and life of the compressor impeller 4, the remaining life considering the damage to the compressor impeller 4 up to the current moment can be calculated from the stress σ calculated in the stress calculation step S2 and the metal temperature Tm calculated in the metal temperature calculation step S4. Therefore, the remaining life of the compressor impeller 4 can be evaluated with good accuracy.

[0035] (Permissible actuation time of the compressor impeller) In several implementations, such as Figure 2 As shown, the remaining service life assessment step S5 includes the Larsson-Miller parameter calculation step S51, which calculates the Larsson-Miller parameter LMP from the stress σ calculated in the stress calculation step S2, using the correlation between the stress σ in the compressor impeller 4 obtained in advance (third correlation information R3); and the allowable actuation time calculation step S52, which calculates the allowable actuation time tr of the compressor impeller 4 from the Larsson-Miller parameter LMP calculated in the Larsson-Miller parameter calculation step S51 and the metal temperature Tm calculated in the metal temperature calculation step S4. The allowable actuation time tr of the compressor impeller 4 represents the time until the compressor impeller 4, subjected to a constant stress σ at a constant metal temperature Tm, breaks.

[0036] Before the Larssen-Miller parameter calculation step S51, the third correlation information R3 is obtained. The third correlation information R3 represents the correspondence between the stress σ in the compressor impeller 4 and the Larssen-Miller parameter LMP. When the stress σ is used as input information, the Larssen-Miller parameter LMP corresponding to the input stress σ is obtained as output information. The third correlation information R3 includes lists or tables, mappings, functions, machine learning models, etc., representing the correspondence between the above input information and the above output information. The third correlation information R3 can be created based on steady-state test data, or it can be created based on past performance values ​​or experimental values, numerical analysis results, etc., other than steady-state test data.

[0037] Figure 3 It is an explanatory diagram used to illustrate the relationship between stress in the compressor impeller and the Larssen-Miller parameters. Figure 3 The graph shows the stress σ in the compressor impeller 4 as the vertical axis and the Larsen-Miller parameter LMP as the horizontal axis. Figure 3 The diagram shows a principal curve M1 representing the correlation between stress σ and the Larssen-Miller parameter LMP. Principal curve M1 is derived, for example, from the results of creep rupture tests at several stages of stress σ and metal temperature Tm. Principal curve M1 is included in the third correlation information R3. In one embodiment, in the Larssen-Miller parameter calculation step S51, based on principal curve M1, the Larssen-Miller parameter LMP corresponding to the stress σ calculated in stress calculation step S2 is calculated.

[0038] In the allowable actuation time calculation step S52, the allowable actuation time tr of the compressor impeller 4 is calculated based on the following equation (1), from the Larsen-Miller parameter LMP calculated in the Larsen-Miller parameter calculation step S51 and the metal temperature Tm calculated in the metal temperature calculation step S4. LMP=Tm×(C+log(tr))……(1) Here, LMP represents the Larssen-Miller parameter, Tm is the metal temperature of the compressor impeller 4, C is the material constant, and tr is the allowable actuation time of the compressor impeller 4. Furthermore, in this embodiment, the material constant C = 20.

[0039] According to the method described above, by using the Larssen-Miller parameter (LMP), the allowable actuation time tr of the compressor impeller 4, considering creep damage up to the current moment, can be determined from the stress σ calculated in stress calculation step S2 and the metal temperature Tm calculated in metal temperature calculation step S4. The remaining life of the compressor impeller 4 can be evaluated with good accuracy using the allowable actuation time tr of the compressor impeller 4 calculated in the remaining life evaluation steps S5 (S51 and S52).

[0040] In addition, in the above embodiments, the allowable actuation time tr of the compressor impeller 4 was obtained from the stress σ and the metal temperature Tm using the Larsen-Miller parameter LMP. However, other known extrapolation methods can also be used to obtain the allowable actuation time tr of the compressor impeller 4 from the stress σ and the metal temperature Tm.

[0041] (Damage to the compressor impeller) Figure 4 This is a flowchart of the remaining useful life assessment step in one embodiment of the present invention. In several implementations, such as Figure 4 As shown, the remaining service life assessment step S5 includes: the Larssen-Miller parameter calculation step S51, the allowable actuation time calculation step S52, and the damage degree calculation step S53. In the damage degree calculation step S53, the actual actuation time ta of the compressor impeller 4 is divided by the allowable actuation time tr of the compressor impeller 4 calculated in the allowable actuation time calculation step S52 to calculate the damage degree D of the compressor impeller 4.

[0042] like Figure 4 As shown, in the remaining life evaluation step S5 above, the damage degree D of the compressor impeller 4 calculated in the damage degree calculation step S53 is used to evaluate the compressor impeller 4 (compressor impeller evaluation step S54).

[0043] According to the above method, in the damage degree calculation step S53, the damage degree D of the compressor impeller 4 can be calculated from the actual actuation time ta and the allowable actuation time tr of the compressor impeller 4. Since the damage degree D of the compressor impeller 4 can be calculated in the damage degree calculation step S53, the damage degree of the compressor impeller 4 can be determined, and the remaining life of the compressor impeller 4 can be evaluated with good accuracy.

[0044] (Cumulative damage to the compressor impeller) Figure 5 This is a flowchart of the remaining useful life assessment step in one embodiment of the present invention. In several implementations, such as Figure 5 As shown, the remaining life assessment step S5 includes: the Larsen-Miller parameter calculation step S51, the allowable actuation time calculation step S52, the classification damage degree calculation step S55, and the cumulative damage degree calculation step S56.

[0045] In the classification damage degree calculation step S55, in each unit period, the actual actuation time ta of the compressor impeller 4 in the unit period is divided by the allowable actuation time tr of the compressor impeller 4 calculated in the allowable actuation time calculation step S52, and the classification damage degree Di, which is the damage degree of the compressor impeller 4 per unit period, is calculated. In the cumulative damage degree calculation step S56, the sum of the classification damage degrees Di up to now is calculated, which is the cumulative damage degree Dc.

[0046] Figure 6 This is an explanatory diagram illustrating the calculation method for the degree of cumulative damage. Figure 6 The graph shows the time t from the start of actuation of the compressor impeller 4 (t0) as the horizontal axis and the cumulative damage level Dc as the vertical axis. It is assumed that the compressor impeller 4 is damaged when the cumulative damage level Dc reaches 1, and the period from the start of actuation (t0) to the cumulative damage level Dc reaching 1 is defined as the total lifespan L of the compressor impeller 4. In the damage level calculation step S55, as follows... Figure 6 As shown, the classification damage degree Di (i is a natural number greater than or equal to 1, referred to as t1, t2, t3 in the figure) is calculated for each unit period ti (i is a natural number greater than or equal to 1, referred to as D1, D2, D3 in the figure). The cumulative damage degree Dc calculated in the cumulative damage degree calculation step S56 is the sum of the classification damage degrees Di up to the current point, i.e., up to the calculation of the cumulative damage degree Dc, and is calculated by the following formula (2). Dc=ΣDi(i is a natural number greater than 2)……(2)

[0047] like Figure 5 As shown, in the remaining life evaluation step S5, the cumulative damage degree Dc of the compressor impeller 4 calculated in the cumulative damage degree calculation step S56 is used to evaluate the compressor impeller 4 (compressor impeller evaluation step S57). Specifically, the difference between the current cumulative damage degree Dc and 1 is calculated, and based on this difference, the remaining life of the compressor impeller 4 for each future load mode can be calculated. Furthermore, the cumulative damage degree Dc can also be directly used in the evaluation of the remaining life of the compressor impeller 4. That is, when the cumulative damage degree Dc reaches 1, the compressor impeller 4 can be replaced.

[0048] According to the method described above, the cumulative damage level Dc can be calculated in the remaining life evaluation step S5 (S55, S56). Since the current damage level of the compressor impeller 4 can be determined by the cumulative damage level Dc calculated in the remaining life evaluation step S5, the remaining life of the compressor impeller 4 can be evaluated with good accuracy.

[0049] In several implementations, such as Figure 2As shown, in the above-mentioned outlet temperature acquisition step S3, the temperature obtained by adding the temperature difference ΔT generated by the intercooler 7 to the temperature Td of the actuating fluid of the compressor impeller 4 measured at a location further downstream of the intercooler 7 is used as the outlet temperature Te.

[0050] According to the method described above, in the outlet temperature acquisition step S3, by adding the temperature difference ΔT generated by the intercooler 7 to the temperature Td of the actuating fluid of the compressor impeller 4, which is located downstream of the intercooler 7, the outlet temperature Te of the compressor impeller 4 can be estimated with good accuracy. Therefore, in the remaining life evaluation step S5, the remaining life of the compressor impeller 4 can be evaluated with good accuracy. Furthermore, according to the method described above, the outlet temperature Te of the compressor impeller 4 can be obtained using the temperature Td of the actuating fluid of the compressor impeller 4, which is typically measured in the engine system 2 equipped with the turbocharger 3, located downstream of the intercooler 7. According to the method described above, even if a temperature measuring device for measuring the outlet temperature Te of the compressor impeller 4 is not provided in the engine system 2, the remaining life evaluation method 1 for the compressor impeller 4 can still be performed. Additionally, the estimation of the outlet temperature Te of the compressor impeller 4 in the outlet temperature acquisition step S3 can also be performed by the control device 11 or the remaining life evaluation device described above.

[0051] In several other embodiments, in the above-described outlet temperature acquisition step S3, the outlet temperature Te of the compressor impeller 4 is estimated from the inlet temperature Ts of the compressor impeller 4 measured by the first temperature measuring device 23 based on correlation information (e.g., performance indicators of the compressor 32) indicating the correlation between the inlet temperature Ts and the outlet temperature Te of the compressor impeller 4.

[0052] (Turbocharger speed) Figure 7 This is a flowchart of the speed acquisition step in one embodiment of the present invention. In the case where the engine system 2 described above does not have the first speed measuring device 25 configured to measure the speed N of the turbocharger 3, it is necessary to determine the speed N of the turbocharger 3. In several embodiments, such as Figure 7 As shown, the above-mentioned speed acquisition step S1 includes a pressure ratio acquisition step S11, a flow rate acquisition step S12, and a speed calculation step S13.

[0053] In the pressure ratio acquisition step S11, the pressure ratio Pr of the compressor impeller 4 is acquired. In the illustrated embodiment, the pressure ratio acquisition step S11 includes: an inlet pressure measurement step S14, measuring the inlet pressure Ps of the compressor impeller 4; an outlet pressure acquisition step S15, acquiring the outlet pressure Pe of the compressor impeller 4; and a pressure ratio calculation step S16, calculating the pressure ratio Pr of the compressor impeller 4 from the inlet pressure Ps measured in the inlet pressure measurement step S14 and the outlet pressure Pe of the compressor impeller 4 acquired in the outlet pressure acquisition step S15.

[0054] In the flow acquisition step S12, the flow rate Fr of the compressor impeller 4 is acquired. In the flow acquisition step S12, the flow rate Fr of the compressor impeller 4 is estimated using parameters typically measured in the engine specifications or engine system 2 and by known methods.

[0055] In the speed calculation step S13, the speed N of the booster 3 is calculated by using the correlation between the pressure ratio Pr and flow rate Fr of the compressor impeller 4 and the speed N of the booster 3 (the fourth correlation information R4) obtained in advance, from the pressure ratio Pr obtained in the pressure ratio acquisition step S11 and the flow rate Fr obtained in the flow rate acquisition step S12.

[0056] Before the speed calculation step S13, the fourth correlation information R4 is obtained. The fourth correlation information R4 represents the correspondence between the pressure ratio Pr and flow rate Fr of the compressor impeller 4 and the speed N of the booster 3. When the pressure ratio Pr and flow rate Fr are used as input information, the speed N corresponding to the pressure ratio Pr and flow rate Fr used as input information can be obtained as output information. The fourth correlation information R4 includes lists or tables, mappings, functions, machine learning models, etc., that represent the correspondence between the above input information and the above output information. The fourth correlation information R4 can be generated based on steady-state test data, or it can be generated based on past performance values ​​or experimental values, numerical analysis results, etc., other than steady-state test data.

[0057] According to the above method, by utilizing the correlation between the pressure ratio Pr, flow rate Fr, and turbocharger speed N of the compressor impeller 4, the turbocharger speed N can be calculated from the pressure ratio Pr obtained in step S11 and the flow rate Fr obtained in step S12. According to the above method, even when the engine system 2 is not equipped with a speed measuring device for measuring the turbocharger speed N, the remaining life evaluation method 1 for the compressor impeller 4 can be executed.

[0058] In several implementations, such as Figure 7As shown, the pressure ratio acquisition step S11 includes the inlet pressure measurement step S14, the outlet pressure acquisition step S15, and the pressure ratio calculation step S16.

[0059] According to the above method, the pressure ratio Pr of the compressor impeller 4 can be calculated from the inlet pressure Ps measured in the inlet pressure measurement step S14 and the outlet pressure Pe obtained in the outlet pressure acquisition step S15. According to the above method, even if a pressure ratio measuring device for measuring the pressure ratio Pr of the compressor impeller 4 is not installed in the engine system 2, the remaining life evaluation method 1 for the compressor impeller 4 can still be performed.

[0060] In several implementations, such as Figure 7 As shown, the speed acquisition step S1 includes a pressure ratio acquisition step S11, a flow rate acquisition step S12, and a speed calculation step S13. The pressure ratio acquisition step S11 includes the inlet pressure measurement step S14, the outlet pressure acquisition step S15, and the pressure ratio calculation step S16. In the outlet pressure acquisition step S15, the pressure Pd of the actuating fluid of the compressor impeller 4, measured at a location further downstream of the intercooler 7, is added to obtain the pressure obtained by adding the pressure loss ΔP generated by the intercooler 7, and this pressure is taken as the outlet pressure Pe.

[0061] In the outlet pressure acquisition step S15, the outlet pressure Pe of the compressor impeller 4 is acquired. The outlet pressure Pe of the compressor impeller 4 is the pressure of the combustion gas (the actuating fluid of the compressor impeller 4) located downstream of the compressor impeller 4 in the combustion gas supply line 6 and upstream of the intercooler 7. Due to the pressure loss ΔP in the intercooler 7, the pressure Pd of the combustion gas located downstream of the intercooler 7 is lower than the outlet pressure Pe of the compressor impeller 4.

[0062] In the illustrated embodiment, in the outlet pressure acquisition step S15, the pressure obtained by adding the pressure loss ΔP generated by the intercooler 7 to the pressure Pd measured by the second pressure measuring device 22 is acquired as the outlet pressure Pe. The pressure loss ΔP is preset based on the specifications of the intercooler 7 between the outlet pressure acquisition steps S15.

[0063] According to the method described above, in the outlet pressure acquisition step S15, by adding the pressure loss ΔP generated by the intercooler 7 to the pressure Pd of the actuating fluid of the compressor impeller 4, which is located downstream of the intercooler 7, the outlet pressure Pe of the compressor impeller 4 can be estimated with good accuracy. Therefore, in the pressure ratio calculation step S16, the pressure ratio Pr of the compressor impeller 4 can be estimated with good accuracy. Furthermore, according to the method described above, the pressure ratio Pr of the compressor impeller 4 can be estimated by using the pressure Pd of the actuating fluid of the compressor impeller 4, which is located downstream of the intercooler 7, and the inlet pressure Ps of the compressor impeller 4, which are typically measured in the engine system 2 equipped with the turbocharger 3. According to the method described above, even if the engine system 2 is not equipped with a pressure measuring device for measuring the outlet pressure Pe of the compressor impeller 4 or a pressure ratio measuring device for measuring the pressure ratio Pr of the compressor impeller 4, the remaining life evaluation method 1 for the compressor impeller 4 can still be performed. In addition, the estimation of outlet pressure Pe or pressure ratio calculation step S16, flow rate acquisition step S12 and speed calculation step S13 in pressure ratio acquisition step S11 can also be performed by the control device 11 or the remaining life evaluation device mentioned above.

[0064] (Correction for remaining lifetime) In several implementations, such as Figure 8 As shown, during the periodic maintenance of the turbocharger 3, at least one parameter Qi of the compressor impeller 4 is measured. The measured parameter Qi of the compressor impeller 4 can be used to correct the evaluation result of the remaining life of the compressor impeller 4 in the remaining life evaluation step S5 described above. Details of the at least one parameter Qi used for remaining life correction will be described later, and it may include at least one of the following: parameters obtained from a replica of the compressor impeller 4; deformation of the compressor impeller 4; hardness of the compressor impeller 4; thickness of the oxide film formed on the surface of the compressor impeller 4; resistance of the compressor impeller 4; and size of internal defects in the compressor impeller 4.

[0065] exist Figure 8 In the example shown, the horizontal axis represents the actual actuation time from the start of operation of the compressor impeller 4 (the cumulative actuation time from when the compressor impeller 4 was new), and the vertical axis represents the remaining life of the compressor impeller 4.

[0066] exist Figure 8 In the example shown, before the compressor impeller 4 starts operating (when the compressor impeller 4 is new), a reference value (initial value) of at least one of the above parameters Qi is measured. However, depending on the type of parameter Qi, this reference value measurement is not mandatory.

[0067] During the period E1 from the start of operation of compressor impeller 4 to the first scheduled overhaul of booster 3, the remaining life of compressor impeller 4 calculated in the remaining life evaluation step S5 (the remaining life calculated using the history of stress σ and metal temperature Tm in compressor impeller 4) is directly evaluated as the remaining life of compressor impeller 4.

[0068] Then, during the first routine maintenance, the casing of the booster 3 is opened, and at least one of the above-mentioned parameters Qi of the compressor impeller 4 is measured.

[0069] During the period E2 from the first scheduled maintenance of the booster 3 to the second scheduled maintenance, the evaluation result of the remaining life of the compressor impeller 4 (calculated using the history of stress σ and metal temperature Tm in the compressor impeller 4) in the remaining life evaluation step S5 is corrected using at least one of the parameters Qi measured during the first scheduled maintenance. For example, by calculating the change of at least one parameter Qi during the period E1 from the baseline value of at least one parameter Qi measured before the start of operation of the compressor impeller 4 and the at least one parameter Qi measured during the first scheduled maintenance, the evaluation result of the remaining life of the compressor impeller 4 in the remaining life evaluation step S5 can be corrected based on the change of at least one parameter Qi during the calculated period E1.

[0070] Furthermore, for example, the remaining life of the compressor impeller 4 calculated using the at least one parameter Qi measured during the first periodic maintenance (e.g., the remaining life of the compressor impeller 4 calculated based on the change of the at least one parameter Qi during period E1) can be used as the initial value of the remaining life of the compressor impeller 4 evaluated in the remaining life evaluation step S5 during the period from the first periodic maintenance to the second periodic maintenance (the remaining life of the compressor impeller 4 at the time of the first periodic maintenance).

[0071] Thus, during the period from the nth (n is an integer greater than or equal to 1) periodic overhaul of the turbocharger 3 to the (n+1)th periodic overhaul, the evaluation result of the remaining life of the compressor impeller 4 (calculated using the history of stress σ and metal temperature Tm in the compressor impeller 4) in the remaining life evaluation step S5 can be corrected using at least one of the parameters Qi measured during the nth periodic overhaul. In this case, during the period from the nth to the (n+1)th periodic overhaul of the turbocharger 3, the change of parameter Qi from before the start of operation of the compressor impeller 4 to the nth periodic overhaul is calculated using the baseline value of parameter Qi measured before the start of operation of the compressor impeller 4 and the parameter Qi measured during the nth periodic overhaul. Based on the calculated change of parameter Qi, the evaluation result of the remaining life of the compressor impeller 4 in the remaining life evaluation step S5 can be corrected.

[0072] Furthermore, the remaining life correction here can be a correction of the remaining life of the compressor impeller 4, calculated using at least one of the parameters Qi measured during the nth periodic overhaul, as the initial value of the remaining life of the compressor impeller 4 evaluated in the remaining life evaluation step S5 during the period from the nth to the (n+1)th overhaul. Also, the remaining life correction here can, for example, be performed in... Figure 2 , Figure 4 or Figure 5 The correction for the allowable actuation time tr calculated in S52 shown can also be used in Figure 4 The correction for the degree of damage D calculated in S53 shown can also be used in Figure 5 Correction for the cumulative damage level Dc calculated in S56 shown.

[0073] In addition, Figure 8 In the example shown, the remaining life of the compressor impeller 4 evaluated in the remaining life evaluation step S5 is extended during period E2 based on the measurement results of at least one of the above-mentioned parameters Qi measured during the first periodic maintenance (the solid line in the figure is changed to a single-dotted line for the correction). During the period from the second periodic maintenance to the third periodic maintenance, the remaining life is shortened based on the measurement results of at least one of the above-mentioned parameters Qi measured during the second periodic maintenance (the single-dotted line in the figure is changed to a double-dotted line for the correction).

[0074] As described above, in the remaining life evaluation step S5, the remaining life corresponding to the history of stress σ or metal temperature Tm in the compressor impeller 4 is evaluated, and this evaluation result is corrected using at least one parameter Qi of the compressor impeller 4 measured during the periodic maintenance of the booster 3. This improves the accuracy of the remaining life evaluation of the compressor impeller 4. Consequently, the replacement interval of the compressor impeller 4 can be further extended.

[0075] Next, specific examples of at least one of the above-mentioned parameters Qi measured during periodic maintenance and several examples of methods for correcting the remaining life of the compressor impeller 4 using parameter Qi will be described.

[0076] In several embodiments, the at least one parameter Qi used for correcting the remaining life of the compressor impeller 4 may also include parameters obtained from a replica taken from the surface of the compressor impeller 4 during the periodic maintenance of the turbocharger 3. In this case, for example, a replica of the material structure of the surface of the compressor impeller 4 can be obtained by the replica method, and the evaluation result of the remaining life of the compressor impeller 4 in the remaining life evaluation step S5 described above is corrected based on the remaining life of the compressor impeller 4 evaluated based on changes in this structure (e.g., changes in grain size, changes in minor surface defects (cracks), or the history of damage and regeneration of the oxide film, etc.).

[0077] For example, at least one of the parameters Qi may include the grain size Q1 (average grain size) of the crystal grains contained in the material microstructure of the surface of the compressor impeller 4. In this case, grain size correlation information R5 (reference) representing the correlation between the grain size of the material microstructure of the surface of the compressor impeller 4 and the remaining life of the compressor impeller 4 can be obtained through preliminary experiments or the like. Figure 9 Based on the grain size correlation information R5 and the grain size Q1 of the material microstructure on the surface of the compressor impeller 4 measured during the periodic maintenance of the turbocharger 3, the remaining life of the compressor impeller 4 is evaluated. Then, based on the evaluation results, the evaluation results of the remaining life of the compressor impeller 4 in the above-mentioned remaining life evaluation step S5 are corrected.

[0078] In this case, for example, the remaining life of the compressor impeller 4, evaluated based on the grain size Q1 and grain size correlation information R5 of the material microstructure of the compressor impeller 4 measured during the nth periodic overhaul, can be used as the initial value for the remaining life of the compressor impeller 4 evaluated in the remaining life evaluation step S5 during the period from the nth to the (n+1)th overhaul. Furthermore, Figure 9 The correlation between the grain size of the material structure on the surface of the compressor impeller 4 and the remaining life of the compressor impeller 4, as illustrated in the figure, indicates that as the grain size of the material structure on the surface of the compressor impeller 4 increases, the remaining life of the compressor impeller 4 decreases (the grain size of the material structure on the surface of the compressor impeller 4 increases over time).

[0079] Thus, by using parameters obtained from a replica of the compressor impeller 4 during the periodic maintenance of the booster 3, the evaluation result of the remaining life of the compressor impeller 4 in the aforementioned remaining life evaluation step S5 (the remaining life corresponding to the history of stress σ or metal temperature Tm in the compressor impeller 4) can be corrected, thereby improving the accuracy of the evaluation of the remaining life of the compressor impeller 4. This further extends the replacement interval of the compressor impeller 4.

[0080] In several embodiments, at least one of the parameters Qi used for correcting the remaining life of the compressor impeller 4 may include the strain Q2 (deformation) of the compressor impeller 4. Furthermore, strain is a value representing how much a point of matter within an object displaces per unit length in the object's reference state (initial state).

[0081] In this case, strain correlation information R6 (reference) representing the correlation between the strain of the compressor impeller 4 and the remaining life of the compressor impeller 4 is obtained through preliminary experiments, etc. Figure 10 Based on the strain correlation information R6 and the strain Q2 of the compressor impeller 4 measured during the periodic maintenance of the booster 3, the remaining life of the compressor impeller 4 is evaluated. Then, based on the evaluation results, the evaluation results of the remaining life of the compressor impeller 4 in the above-mentioned remaining life evaluation step S5 are corrected.

[0082] In this case, for example, the remaining life of the compressor impeller 4, evaluated based on the strain Q2 and strain correlation information R6 measured during the nth periodic overhaul, can be used as the initial value for the remaining life of the compressor impeller 4 evaluated in the remaining life evaluation step S5 from the nth to the (n+1)th overhaul. Furthermore, Figure 10 The correlation between the strain of the compressor impeller 4 and the remaining life of the compressor impeller 4 illustrated in the figure indicates that as the strain of the compressor impeller 4 increases, the remaining life of the compressor impeller 4 decreases (as the strain of the compressor impeller 4 increases over time).

[0083] Thus, by using the strain of the compressor impeller 4 measured during the periodic maintenance of the booster 3, the evaluation result of the remaining life of the compressor impeller 4 in the aforementioned remaining life evaluation step S5 (the remaining life corresponding to the history of stress σ or metal temperature Tm in the compressor impeller 4) can be corrected, thereby improving the accuracy of the evaluation of the remaining life of the compressor impeller 4. This extends the replacement interval of the compressor impeller 4.

[0084] In several embodiments, at least one of the parameters Qi used for correcting the remaining life of the compressor impeller 4 may include the hardness Q3 of the compressor impeller 4. In this case, hardness correlation information R7 (referencing) representing the correlation between the hardness of the compressor impeller 4 and the remaining life of the compressor impeller 4 is obtained through preliminary experiments, etc. Figure 11 Based on the hardness correlation information R7 and the hardness Q3 of the compressor impeller 4 measured during the periodic maintenance of the booster 3, the remaining life of the compressor impeller 4 is evaluated. Then, based on the evaluation results, the evaluation results of the remaining life of the compressor impeller 4 in the above-mentioned remaining life evaluation step S5 are corrected.

[0085] In this case, for example, the remaining life of the compressor impeller 4, evaluated based on the hardness Q3 and hardness correlation information R7 measured during the nth periodic overhaul, can be used as the initial value for the remaining life of the compressor impeller 4 evaluated in the remaining life evaluation step S5 from the nth to the (n+1)th overhaul. Furthermore, Figure 11 The correlation between the hardness of the compressor impeller 4 and the remaining life of the compressor impeller 4 illustrated in the figure indicates that as the hardness of the compressor impeller 4 decreases, the remaining life of the compressor impeller 4 decreases (the hardness of the compressor impeller 4 decreases over time).

[0086] Thus, by using the hardness of the compressor impeller 4 measured during the periodic maintenance of the booster 3, the evaluation result of the remaining life of the compressor impeller 4 in the aforementioned remaining life evaluation step S5 (the remaining life corresponding to the history of stress σ or metal temperature Tm in the compressor impeller 4) can be corrected, thereby improving the accuracy of the evaluation of the remaining life of the compressor impeller 4. This extends the replacement interval of the compressor impeller 4.

[0087] In several embodiments, the at least one parameter Qi used for correcting the remaining life of the compressor impeller 4 may include the thickness Q4 of the oxide film formed on the surface of the compressor impeller 4. In this case, film thickness correlation information R8 (refer to) representing the correlation between the thickness of the oxide film formed on the surface of the compressor impeller 4 and the remaining life of the compressor impeller 4 is obtained through preliminary experiments or the like. Figure 12 Based on the oxide film thickness correlation information R8 and the oxide film thickness Q4 measured during the periodic maintenance of the booster 3, the remaining life of the compressor impeller 4 is evaluated. Then, based on the evaluation results, the remaining life of the compressor impeller 4 evaluated in the above-mentioned remaining life evaluation step S5 is corrected.

[0088] In this case, for example, the remaining life of the compressor impeller 4, evaluated based on the oxide film thickness Q4 measured during the nth periodic maintenance and the film thickness correlation information R8, can be used as the initial value for the remaining life of the compressor impeller 4 evaluated in the remaining life evaluation step S5 during the period from the nth to the (n+1)th maintenance. Additionally, formed in Figure 12 The correlation between the thickness of the oxide film on the surface of the compressor impeller 4 and the remaining life of the compressor impeller 4, as illustrated, indicates that the remaining life of the compressor impeller 4 decreases as the thickness of the oxide film decreases (the thickness of the oxide film decreases over time). Furthermore, the thickness Q4 of the oxide film formed on the surface of the compressor impeller 4 can be measured, for example, by non-destructive testing such as ultrasonic testing (UT).

[0089] Thus, by using the oxide film thickness Q4 measured during the periodic maintenance of the booster 3, the evaluation result of the remaining life of the compressor impeller 4 in the aforementioned remaining life evaluation step S5 (the remaining life corresponding to the history of stress σ or metal temperature Tm in the compressor impeller 4) can be corrected, thereby improving the accuracy of the evaluation of the remaining life of the compressor impeller 4. This extends the replacement interval of the compressor impeller 4.

[0090] In several embodiments, at least one of the parameters Qi used for correcting the remaining life of the compressor impeller 4 may include the resistance Q5 of the compressor impeller 4. In this case, resistance correlation information R9 (referencing) representing the correlation between the resistance of the compressor impeller 4 and the remaining life of the compressor impeller 4 is obtained through preliminary experiments, etc. Figure 13 Based on the resistance correlation information R9 and the resistance Q5 of the compressor impeller 4 measured during the periodic maintenance of the booster 3, the remaining life of the compressor impeller 4 is evaluated. Then, based on the evaluation results, the remaining life of the compressor impeller 4 evaluated in the above-mentioned remaining life evaluation step S5 is corrected.

[0091] In this case, for example, the remaining life of the compressor impeller 4, evaluated based on the resistance Q5 and resistance correlation information R9 measured during the nth periodic overhaul, can be used as the initial value for the remaining life of the compressor impeller 4 evaluated in the remaining life evaluation step S5 from the nth to the (n+1)th overhaul. Additionally, Figure 13 The correlation between the resistance of the compressor impeller 4 and the remaining life of the compressor impeller 4 illustrated in the figure indicates that as the material composition or size of the compressor impeller 4 changes, the resistance of the compressor impeller 4 decreases and the remaining life of the compressor impeller 4 decreases (the resistance of the compressor impeller 4 decreases over time).

[0092] Thus, by using the resistance Q5 of the compressor impeller 4 measured during the periodic maintenance of the booster 3, the evaluation result of the remaining life of the compressor impeller 4 in the aforementioned remaining life evaluation step S5 (the remaining life corresponding to the history of stress σ or metal temperature Tm in the compressor impeller 4) can be corrected, thereby improving the accuracy of the evaluation of the remaining life of the compressor impeller 4. This extends the replacement interval of the compressor impeller 4.

[0093] In several embodiments, the aforementioned parameter Qi used for correcting the remaining life of the compressor impeller 4 may include the size Q6 of an internal defect in the compressor impeller 4. In this case, internal defect size correlation information R10 (referencing) representing the correlation between the size of the internal defect in the compressor impeller 4 and the remaining life of the compressor impeller 4 is obtained through preliminary experiments, etc. Figure 14 Based on the internal defect size correlation information R10 and the internal defect size Q6 of the compressor impeller 4 measured during the periodic maintenance of the booster 3, the remaining life of the compressor impeller 4 is evaluated. Then, based on the evaluation results, the remaining life of the compressor impeller 4 evaluated in the above-mentioned remaining life evaluation step S5 is corrected.

[0094] In this case, for example, the remaining life of the compressor impeller 4, evaluated based on the size Q6 of the internal defect of the compressor impeller 4 measured during the nth periodic overhaul and the correlation information R10 of the internal defect size, can be used as the initial value of the remaining life of the compressor impeller 4 evaluated in the remaining life evaluation step S5 during the period from the nth to the (n+1)th overhaul. Additionally, Figure 14 The correlation between the size of the internal defect in the compressor impeller 4 and the remaining life of the compressor impeller 4, as illustrated, indicates that the remaining life of the compressor impeller 4 decreases as the size of the internal defect increases (the size of the internal defect increases over time). Furthermore, the size Q6 of the internal defect in the compressor impeller 4 can be measured using non-destructive testing methods such as ultrasonic testing.

[0095] Thus, by using the size Q6 of the internal defect in the compressor impeller 4 measured during the periodic maintenance of the booster 3, the evaluation result of the remaining life of the compressor impeller 4 in the aforementioned remaining life evaluation step S5 (the remaining life corresponding to the history of stress σ or metal temperature Tm in the compressor impeller 4) can be corrected, thereby improving the accuracy of the evaluation of the remaining life of the compressor impeller 4. This extends the replacement interval of the compressor impeller 4.

[0096] This invention is not limited to the embodiments described above, but also includes modifications or appropriate combinations thereof. For example, the evaluation result of the remaining life of the compressor impeller 4 in the remaining life evaluation step S5 can be corrected using two or more of the following parameters: parameter Q1 obtained from a replica of the compressor impeller 4, deformation Q2 of the compressor impeller 4, hardness Q3 of the compressor impeller 4, thickness Q4 of the oxide film formed on the surface of the compressor impeller 4, resistance Q5 of the compressor impeller 4, and size Q6 of internal defects in the compressor impeller 4.

[0097] The contents described in the above-mentioned embodiments are as follows.

[0098] 1) The remaining life evaluation method (1) of the compressor impeller according to at least one embodiment of the present invention is a method (1) of evaluating the remaining life of the compressor impeller (4) of the booster (3) comprising: Speed ​​acquisition step (S1): Acquire the speed (N) of the booster (3); In the stress calculation step (S2), the stress (σ) generated in the compressor impeller (4) is calculated from the rotational speed (N) of the booster (3) obtained in the rotational speed acquisition step (S1); The outlet temperature acquisition step (S3) acquires the outlet temperature (Te) of the compressor impeller (4); The metal temperature calculation step (S4) calculates the metal temperature (Tm) of the compressor impeller (4) from the outlet temperature (Te) obtained in the outlet temperature acquisition step (S3); and The remaining life evaluation step (S5) uses the correlation between the stress (σ), metal temperature (Tm) and life of the compressor impeller (4) obtained in advance to evaluate the remaining life of the compressor impeller (4) based on the stress (σ) calculated in the stress calculation step (S2) and the metal temperature (Tm) calculated in the metal temperature calculation step (S4).

[0099] Based on the history of the stress (σ) or metal temperature (Tm) in the compressor impeller (4) up to the current moment, damage (creep damage, etc.) occurs and develops in the compressor impeller (4). According to the method in 1) above, in the remaining life evaluation step (S5), by utilizing the correlation between the stress (σ), metal temperature (Tm) and life of the compressor impeller (4), the remaining life considering the damage to the compressor impeller (4) up to the current moment can be calculated from the stress (σ) calculated in the stress calculation step (S2) and the metal temperature (Tm) calculated in the metal temperature calculation step (S4). Therefore, the remaining life of the compressor impeller (4) can be evaluated with good accuracy.

[0100] 2) In several embodiments, according to the compressor impeller remaining life evaluation method (1) described in 1) above, the remaining life evaluation step (S5) includes: The Larssen-Miller parameter calculation step (S51) calculates the Larssen-Miller parameter (LMP) from the stress (σ) calculated in the stress calculation step (S2) by utilizing the pre-obtained correlation between the stress (σ) in the compressor impeller (4) and the Larssen-Miller parameter (LMP); and In the allowable actuation time calculation step (S52), the allowable actuation time (tr) of the compressor impeller (4) is calculated from the Larsen-Miller parameter (LMP) calculated in the Larsen-Miller parameter calculation step (S51) and the metal temperature (Tm) calculated in the metal temperature calculation step (S2).

[0101] According to the method described in 2) above, by using the Larssen-Miller parameter (LMP), the allowable actuation time (tr) of the compressor impeller (4) considering creep damage up to the current moment can be determined from the stress (σ) calculated in the stress calculation step (S2) and the metal temperature (Tm) calculated in the metal temperature calculation step (S4). The remaining life of the compressor impeller (4) can be evaluated with good accuracy using the allowable actuation time (tr) of the compressor impeller (4) calculated in the remaining life evaluation step (S5).

[0102] 3) In several embodiments, according to the compressor impeller remaining life evaluation method (1) described in 2) above, the remaining life evaluation step (S5) includes: In the damage calculation step (S53), the actual actuation time (ta) of the compressor impeller (4) is divided by the allowable actuation time (tr) of the compressor impeller (4) calculated in the allowable actuation time calculation step (S52) to calculate the damage degree (D) of the compressor impeller (4).

[0103] According to the method described in 3) above, in the damage degree calculation step (S53), the damage degree (D) of the compressor impeller (4) can be calculated from the actual actuation time (ta) and the allowable actuation time (tr) of the compressor impeller (4). By calculating the damage degree (D) of the compressor impeller (4) in the damage degree calculation step (S53), the damage degree of the compressor impeller (4) can be determined, and thus the remaining life of the compressor impeller (4) can be evaluated with good accuracy.

[0104] 4) In several embodiments, according to the compressor impeller remaining life evaluation method (1) described in 2) above, the remaining life evaluation step (S5) includes: In the damage classification calculation step (S55), in each unit period, the actual actuation time (ta) of the compressor impeller (4) in that unit period is divided by the allowable actuation time (tr) of the compressor impeller (4) calculated in the allowable actuation time calculation step (S52), and the damage classification degree (Di) of the compressor impeller (4) in each unit period is calculated; and The cumulative damage calculation step (S56) calculates the sum of the classified damage levels (Di) up to the present, which is the cumulative damage level (Dc).

[0105] According to the method described in 4) above, the cumulative damage level (Dc) can be calculated in the remaining life evaluation step (S5). By calculating the cumulative damage level (Dc) of the compressor impeller (4) in the remaining life evaluation step (S5), the current damage level of the compressor impeller (4) can be determined, and thus the remaining life of the compressor impeller (4) can be evaluated with good accuracy.

[0106] 5) In several embodiments, according to the compressor impeller remaining life evaluation method (1) according to any one of 1) to 4) above, wherein, in the outlet temperature acquisition step (S3), the outlet temperature (Te) is obtained by adding the temperature difference (ΔT) generated by the intercooler (7) to the temperature (Td) of the actuating fluid of the compressor impeller (4) measured further downstream than the intercooler (7) located further downstream than the compressor impeller (4).

[0107] According to the method described in 5), in the outlet temperature acquisition step (S3), by adding the temperature difference (ΔT) generated by the intercooler (7) to the temperature (Td) of the actuating fluid of the compressor impeller (4) located downstream of the intercooler (7), the outlet temperature (Te) of the compressor impeller (4) can be estimated with good accuracy. Therefore, in the remaining life evaluation step (S5), the remaining life of the compressor impeller (4) can be evaluated with good accuracy. Furthermore, according to the method described in 5), the outlet temperature (Te) of the compressor impeller (4) located downstream of the intercooler (7) can be estimated using the temperature (Td) of the actuating fluid of the compressor impeller (4) located downstream of the intercooler (7), which is typically measured in an engine system (2) equipped with a turbocharger (3). According to the method described in 5), even if a temperature measuring device for measuring the outlet temperature (Te) of the compressor impeller (4) is not provided in the engine system (2), the remaining life evaluation method (1) for the compressor impeller (4) can still be performed.

[0108] 6) In several embodiments, the remaining life evaluation method (1) for the compressor impeller according to any one of 1) to 5) above, wherein the speed acquisition step (S1) includes: Pressure ratio acquisition step (S11): Acquire the pressure ratio (Pr) of the compressor impeller (4); In the flow acquisition step (S12), the flow rate (Fr) of the compressor impeller (4) is acquired; and In the speed calculation step (S13), the speed (N) of the booster (3) is calculated by using the correlation between the pressure ratio (Pr) and flow rate (Fr) of the compressor impeller (4) obtained in advance and the speed (N) of the booster (3) obtained from the pressure ratio acquisition step (S11) and the flow rate (Fr) obtained in the flow rate acquisition step (S12).

[0109] According to the method described in 6), by utilizing the correlation between the pressure ratio (Pr), flow rate (Fr) of the compressor impeller (4) and the rotational speed (N) of the turbocharger (3), the rotational speed (N) of the turbocharger (3) can be calculated from the pressure ratio (Pr) obtained in the pressure ratio acquisition step (S11) and the flow rate (Fr) obtained in the flow rate acquisition step (S12). According to the method described in 6), even if the engine system (2) is not equipped with a rotational speed measuring device for measuring the rotational speed (N) of the turbocharger (3), the remaining life evaluation method (1) of the compressor impeller (4) can be performed.

[0110] 7) In several embodiments, according to the compressor impeller remaining life evaluation method (1) described in 6) above, the pressure ratio acquisition step (S11) includes: Inlet pressure measurement step (S14), the inlet pressure (Ps) of the compressor impeller (4) is measured; In the outlet pressure acquisition step (S15), the outlet pressure (Pe) of the compressor impeller (4) is acquired; and In the pressure ratio calculation step (S16), the pressure ratio (Pr) of the compressor impeller (4) is calculated from the inlet pressure (Ps) of the compressor impeller (4) measured in the inlet pressure measurement step (S14) and the outlet pressure (Pe) of the compressor impeller (4) obtained in the outlet pressure acquisition step (S15).

[0111] According to the method described in 7), the pressure ratio (Pr) of the compressor impeller (4) can be calculated from the inlet pressure (Ps) of the compressor impeller (4) measured in the inlet pressure measurement step (S14) and the outlet pressure (Pe) of the compressor impeller (4) obtained in the outlet pressure acquisition step (S15). According to the method described in 7), even if a pressure ratio measuring device for measuring the pressure ratio (Pr) of the compressor impeller (4) is not provided in the engine system (2), the remaining life evaluation method (1) of the compressor impeller (4) can still be performed.

[0112] 8) In several embodiments, according to the remaining life evaluation method (1) of the compressor impeller described in 7) above, in the outlet pressure acquisition step (S15), the pressure obtained by adding the pressure loss (ΔP) generated by the intercooler (7) to the pressure of the actuating fluid of the compressor impeller (4) measured at a location further downstream than the intercooler (7) located further downstream than the compressor impeller (4) is used as the outlet pressure (Pe).

[0113] According to the method described in 8), in the outlet pressure acquisition step (S15), by adding the pressure loss (ΔP) generated by the intercooler (7) to the pressure (Pd) of the actuating fluid of the compressor impeller (4) located downstream of the intercooler (7), the outlet pressure (Pe) of the compressor impeller (4) can be estimated with good accuracy. Therefore, in the pressure ratio calculation step (S16), the pressure ratio (Pr) of the compressor impeller (4) can be estimated with good accuracy. Furthermore, according to the method described in 8), the pressure ratio (Pr) of the compressor impeller (4) located downstream of the intercooler (7) and the inlet pressure (Ps) of the compressor impeller (4) can be estimated by using the pressure (Pd) of the actuating fluid of the compressor impeller (4) located downstream of the intercooler (7), which is usually measured in an engine system (2) equipped with a turbocharger (3), and the inlet pressure (Ps) of the compressor impeller (4). According to the method described in 8), even if the engine system (2) is not equipped with a pressure measuring device for measuring the outlet pressure (Pe) of the compressor impeller (4) or a pressure ratio measuring device for measuring the pressure ratio (Pr) of the compressor impeller (4), the remaining life evaluation method (1) of the compressor impeller (4) can still be performed.

[0114] 9) In several embodiments, the remaining life evaluation method (1) of the compressor impeller according to any one of 1) to 8) above, wherein the evaluation result of the remaining life of the compressor impeller (4) in the remaining life evaluation step is corrected using at least one parameter of the compressor impeller (4) measured during the periodic maintenance of the booster (3).

[0115] According to the method described in 9) above, the remaining life corresponding to the stress (σ) or metal temperature (Tm) in the compressor impeller (4) is evaluated from the stress (σ) calculated in the stress calculation step (S2) and the metal temperature (Tm) calculated in the metal temperature calculation step (S4). The evaluation result is then corrected using at least one parameter of the compressor impeller measured during the periodic maintenance of the booster (3), thereby improving the accuracy of the evaluation of the remaining life of the compressor impeller (4). As a result, the replacement interval of the compressor impeller 4 can be extended.

[0116] 10) In several embodiments, according to the compressor impeller remaining life evaluation method (1) described in 9) above, if n is set to an integer greater than or equal to 1, then during the period from the nth periodic overhaul of the booster (3) to the (n+1)th periodic overhaul, the evaluation result of the remaining life of the compressor impeller (4) in the remaining life evaluation step is corrected using the at least one parameter measured in the nth periodic overhaul of the booster (3).

[0117] According to the method described in 10), since at least one parameter measured for the compressor impeller (4) during the latest periodic maintenance can be used to correct the evaluation result of the remaining life of the compressor impeller (4) in the remaining life evaluation step, the accuracy of the evaluation of the remaining life of the compressor impeller (4) can be improved. As a result, the replacement interval of the compressor impeller (4) can be extended.

[0118] 11) In several embodiments, according to the remaining life evaluation method (1) of the compressor impeller described in 9) above, wherein the at least one parameter measured during the periodic maintenance includes at least one of the following: a parameter obtained from a replica of the compressor impeller (4), the deformation of the compressor impeller (4), the hardness of the compressor impeller (4), the thickness of the oxide film formed on the surface of the compressor impeller (4), the resistance of the compressor impeller (4), and the size of the internal defects of the compressor impeller (4).

[0119] According to the method described in 11) above, at least one of the following parameters can be used to correct the remaining life evaluated based on the history of stress (σ) or metal temperature (Tm) in the compressor impeller (4): parameters (Q1) obtained from a replica of the compressor impeller (4), deformation of the compressor impeller (4) (Q2), hardness of the compressor impeller (4) (Q3), thickness of the oxide film formed on the surface of the compressor impeller (4) (Q4), resistance of the compressor impeller (4) (Q5), and size of internal defects in the compressor impeller (4) (Q6). This improves the accuracy of the evaluation of the remaining life of the compressor impeller (4) and extends the replacement interval of the compressor impeller (4). Symbol Explanation

[0120] 1-Remaining life evaluation method for compressor impeller, 2-Engine system, 3-Turbocharger, 4-Compressor impeller, 5-Engine, 6-Combustion gas supply line, 7-Intercooler, 8-Exhaust line, 9-Fuel injection valve, 11-Control device, 21-First pressure measuring device, 22-Second pressure measuring device, 23-First temperature measuring device, 24-Second temperature measuring device, 25-First speed measuring device, 31-Rotating shaft, 32-Compressor, 33-Turbine, 34-Compressor housing, 35-Turbine blade, 36-Turbine housing, 51-Cylinder, 52-Piston, 53-Combustion chamber, C-Material constant, D-Damage degree, Dc-Cumulative damage degree, Di-Classified damage degree, E1, E2-Period, Fr-Flow rate, L-Total life, LMP-Larsen-Miller parameter, M1-Master curve, N-Speed, Pd-Pressure, Pe-Outlet pressure, Pr-Pressure ratio, Ps -Inlet pressure, Qi -Parameter, Q1 -Grain size, Q2 -Strain, Q3 -Hardness, Q4 -Oxide film thickness, Q5 -Resistance, Q6 -Internal defect size, R1, R2, R3, R4, R5, R6, R7, R8, R9, R10 -Correlation information, S1 -Spindle speed acquisition step, S2 -Stress calculation step, S3 -Outlet temperature acquisition step, S4 -Metal temperature calculation step, S5 -Remaining life assessment step, S11 -Pressure ratio acquisition step, S12 -Flow rate acquisition step, S13 -Spindle speed calculation step, S14 -Inlet pressure measurement step, S15 -Outlet pressure acquisition step, S16 -Pressure ratio calculation step, S51 -Larsen-Miller parameter calculation step, S52 -Allowable actuation time calculation step, S53 -Damage degree calculation step, Td -Temperature, Te -Outlet temperature, Tm -Metal temperature, Ts -Inlet temperature, ta -Actual actuation time, tr -Allowable actuation time.

Claims

1. A method for evaluating the remaining life of a compressor impeller, wherein the method evaluates the remaining life of the compressor impeller of a booster, the method comprising: The speed acquisition step involves acquiring the speed of the turbocharger. The stress calculation step involves calculating the stress generated in the compressor impeller from the speed of the booster obtained in the speed acquisition step. The outlet temperature acquisition step involves acquiring the outlet temperature of the compressor impeller. The metal temperature calculation step involves calculating the metal temperature of the compressor impeller from the outlet temperature of the compressor impeller obtained in the outlet temperature acquisition step. and The remaining service life assessment step utilizes the pre-obtained correlation between stress, metal temperature, and service life in the compressor impeller. Based on the stress calculated in the stress calculation step and the metal temperature calculated in the metal temperature calculation step, the remaining service life of the compressor impeller is evaluated. The remaining lifetime assessment steps include: The Larssen-Miller parameter calculation step utilizes the pre-obtained correlation between the stress in the compressor impeller and the Larssen-Miller parameter to calculate the Larssen-Miller parameter from the stress calculated in the stress calculation step; and The permissible actuation time calculation step calculates the permissible actuation time of the compressor impeller from the Larssen-Miller parameters calculated in the Larssen-Miller parameter calculation step and the metal temperature calculated in the metal temperature calculation step.

2. The method for evaluating the remaining life of a compressor impeller according to claim 1, wherein, The remaining lifetime assessment steps include: The damage degree calculation step involves dividing the actual actuation time of the compressor impeller by the allowable actuation time of the compressor impeller calculated in the allowable actuation time calculation step to calculate the damage degree of the compressor impeller.

3. The method for evaluating the remaining life of a compressor impeller according to claim 1, wherein, The remaining lifetime assessment steps include: The damage severity calculation step involves dividing the actual actuation time of the compressor impeller within each unit period by the allowable actuation time of the compressor impeller calculated in the allowable actuation time calculation step, thereby calculating the damage severity of the compressor impeller in each unit period, i.e., the damage severity classification. The cumulative damage calculation step involves calculating the sum of the classified damage levels up to the present, which is the cumulative damage level.

4. The method for evaluating the remaining life of a compressor impeller according to claim 1, wherein, In the outlet temperature acquisition step, the outlet temperature is obtained by adding the temperature difference generated by the intercooler to the temperature of the actuating fluid of the compressor impeller, which is located further downstream of the intercooler than the compressor impeller.

5. The method for evaluating the remaining life of a compressor impeller according to claim 1, wherein, The speed acquisition step includes: The pressure ratio acquisition step involves acquiring the pressure ratio of the compressor impeller. The flow rate acquisition step involves acquiring the flow rate of the compressor impeller; and The speed calculation step utilizes the correlation between the pressure ratio and flow rate of the compressor impeller and the speed of the booster obtained in advance, and calculates the speed of the booster from the pressure ratio obtained in the pressure ratio acquisition step and the flow rate obtained in the flow rate acquisition step.

6. The method for evaluating the remaining life of a compressor impeller according to claim 5, wherein, The pressure ratio acquisition step includes: The inlet pressure measurement step involves measuring the inlet pressure of the compressor impeller. The outlet pressure acquisition step involves acquiring the outlet pressure of the compressor impeller; and The pressure ratio calculation step involves calculating the pressure ratio of the compressor impeller from the inlet pressure of the compressor impeller measured in the inlet pressure measurement step and the outlet pressure of the compressor impeller obtained in the outlet pressure acquisition step.

7. The method for evaluating the remaining life of a compressor impeller according to claim 6, wherein, In the outlet pressure acquisition step, the outlet pressure is obtained by adding the pressure loss generated by the intercooler to the pressure of the actuating fluid of the compressor impeller, which is located further downstream of the compressor impeller than the intercooler.

8. The method for evaluating the remaining life of a compressor impeller according to any one of claims 1 to 7, wherein, The evaluation result of the remaining life of the compressor impeller in the remaining life evaluation step is corrected using at least one parameter of the compressor impeller measured during the periodic maintenance of the turbocharger.

9. The method for evaluating the remaining life of a compressor impeller according to claim 8, wherein, If n is set to an integer greater than or equal to 1, then during the period from the nth periodic overhaul of the turbocharger to the (n+1)th periodic overhaul, the evaluation result of the remaining life of the compressor impeller in the remaining life evaluation step is corrected using the at least one parameter measured during the nth periodic overhaul of the turbocharger.

10. The method for evaluating the remaining life of a compressor impeller according to claim 8, wherein, The at least one parameter measured during the periodic maintenance includes at least one of the following: a parameter obtained from a replica of the compressor impeller, the deformation of the compressor impeller, the hardness of the compressor impeller, the thickness of the oxide film formed on the surface of the compressor impeller, the resistance of the compressor impeller, and the size of internal defects in the compressor impeller.

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