Method for evaluating the remaining lifespan of a compressor impeller

Abstract

To provide a remaining life evaluation method for a compressor impeller capable of accurately evaluating a remaining life of a compressor impeller by using operational data related to a supercharger.SOLUTION: A remaining life evaluation method for a compressor impeller for evaluating a remaining life of a compressor impeller included in a supercharger, comprises: a rotation speed acquisition step of acquiring a rotation speed of a supercharger; a stress calculation step of calculating stress occurring in the compressor impeller from the rotation speed of the supercharger acquired in the rotation speed acquisition step; a metal temperature measurement step of measuring a metal temperature of the compressor impeller; and a remaining life evaluation step of evaluating the remaining life of the compressor impeller from the stress calculated in the stress calculation step and the metal temperature measured in the metal temperature measurement step, using a relation between the stress, the metal temperature, and the life of the compressor impeller acquired in advance.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a method for evaluating the remaining life of a compressor impeller of a supercharger, which evaluates the remaining life of the compressor impeller of the supercharger.

Background Art

[0002] Conventionally, for the compressor impeller of a supercharger, a period obtained by adding a predetermined margin to the remaining life estimated based on the material properties of the material constituting the compressor impeller has been set as the replacement period.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since the above replacement period does not take into account the change in the state of the compressor impeller when the supercharger is actually operated, there is a possibility of deviation from the actual remaining life. Therefore, when the compressor impeller is replaced when the above replacement period arrives, the compressor impeller may be replaced earlier than the actual life, and there is a problem that the replacement frequency of the compressor impeller becomes high. In order to make the replacement frequency of the compressor impeller appropriate, it is desired to more accurately evaluate the remaining life of the compressor impeller.

[0005] Several methods have been proposed to evaluate the remaining lifespan of a compressor impeller, 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 compressor wheel creep. This creep monitoring algorithm monitors creep by monitoring the amount of time spent operating under different combinations of detected compressor inlet temperature and calculated compressor pressure ratio. The above combinations include a creep score representing the stress on the compressor wheel caused by a specific combination. The product of the amount of time under a specific combination and the creep score becomes the creep stress damage that occurs under that specific combination, and the total creep stress damage becomes the monitored creep.

[0006] In view of the circumstances described above, the object of at least one embodiment of this disclosure is to provide a compressor impeller remaining life evaluation method that can accurately evaluate the remaining life of a compressor impeller by utilizing operating data related to a supercharger. [Means for solving the problem]

[0007] A method for evaluating the remaining life of a compressor impeller according to one embodiment of the present disclosure is: A method for evaluating the remaining lifespan of a compressor impeller in a supercharger, wherein the remaining lifespan of the compressor impeller is evaluated, A rotational speed acquisition step to acquire the rotational speed of the supercharger, A stress calculation step which calculates the stress generated in the compressor impeller from the rotational speed of the supercharger obtained in the rotational speed acquisition step, A metal temperature measurement step for measuring the metal temperature of the compressor impeller, The system includes a remaining life evaluation step, which uses the relationship between stress, metal temperature, and lifespan in the compressor impeller, obtained in advance, to evaluate the remaining lifespan of the compressor impeller based on the stress calculated in the stress calculation step and the metal temperature measured in the metal temperature measurement step. [Effects of the Invention]

[0008] According to at least one embodiment of the present disclosure, a method for evaluating the remaining lifespan of a compressor impeller is provided that can accurately evaluate the remaining lifespan of the compressor impeller by utilizing operating data related to the supercharger. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram illustrating the configuration of an engine system equipped with a compressor impeller, which is the subject of evaluation in the compressor impeller remaining life evaluation method according to one embodiment of the present disclosure. [Figure 2] This is a schematic cross-sectional view along the axis of the turbocharger in one embodiment of the present disclosure. [Figure 3] This is a schematic cross-sectional view along the axis of the compressor side of a turbocharger in one embodiment of the present disclosure. [Figure 4] This is a flowchart of a method for evaluating the remaining life of a compressor impeller according to one embodiment of the present disclosure. [Figure 5] This is an explanatory diagram illustrating the relationship between stress and Larson-Miller parameters in a compressor impeller. [Figure 6] This is a flowchart of the rotational speed acquisition step in one embodiment of the present disclosure. [Modes for carrying out the invention]

[0010] Hereinafter, several embodiments of this disclosure will be described with reference to the attached drawings. However, the dimensions, materials, shapes, relative arrangements, etc., of the components described or shown in the drawings as embodiments are not intended to limit the scope of this disclosure, but are merely illustrative examples. For example, expressions describing relative or absolute arrangements such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" should not only strictly describe such arrangements, but also describe states of relative displacement with tolerances or angles or distances that allow for the same function to be achieved. For example, expressions such as "identical," "equal," and "homogeneous" that describe things being in an equal state not only describe a state of being strictly equal, but also describe a state in which there is a tolerance or a difference that is sufficient to achieve the same function. For example, expressions describing shapes such as squares or cylinders shall not only represent geometrically precise shapes such as squares or cylinders, but also shapes that include protrusions, chamfers, etc., to the extent that the same effect can be achieved. On the other hand, expressions such as "possessing," "including," or "having" one component are not exclusive expressions that exclude the existence of other components. Note that similar configurations may be given the same reference numerals and their explanations may be omitted.

[0011] Figure 1 is a schematic diagram illustrating the configuration of an engine system equipped with a compressor impeller, which is the subject of evaluation in the compressor impeller remaining life evaluation method according to one embodiment of the present disclosure. The compressor impeller remaining life evaluation method 1 according to some embodiments of the present disclosure is for evaluating the remaining life of a compressor impeller 4 in a supercharger 3. The supercharger 3 is mounted in an engine system 2 equipped with an engine 5, as shown in Figure 1.

[0012] (Engine system) As shown in Figure 1, the engine system 2 comprises an engine (engine body) 5 configured to generate power by burning fuel internally, a combustion gas supply line 6 for compressing and supplying a combustion gas (e.g., air) used for combustion inside the engine 5, a supercharger 3 having a compressor impeller 4 provided on the combustion gas supply line 6, and an intercooler 7 provided downstream of the compressor impeller 4 on the combustion gas supply line 6. The intercooler 7 consists of a heat exchanger configured to cool the combustion gas passing through the intercooler 7.

[0013] In the illustrated embodiment, as shown in FIG. 1, the engine system 2 further includes an exhaust gas discharge line 8 for guiding the 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 each device (such as the engine 5 and the fuel injection valve 9) in the engine system 2.

[0014] The engine 5 includes at least one cylinder 51 and at least one piston 52 respectively housed reciprocally along the axial direction inside the at least one cylinder 51. The engine 5 has an internal combustion chamber 53 partitioned by the cylinder 51 and the piston 52. The combustion chamber 53 is connected to allow gas to flow downstream of the intercooler 7 in the combustion gas supply line 6. The combustion gas supply line 6 is a flow path for guiding the combustion gas from the compressor 32 to the combustion chamber 53. The combustion chamber 53 is connected to allow gas to flow to the exhaust gas discharge line 8. The exhaust gas discharge line 8 is a flow path for circulating the exhaust gas discharged from the combustion chamber 53 to the turbine 33.

[0015] The fuel injected from the fuel injection valve 9 into the combustion chamber 53 or the combustion gas supply line 6 is mixed with the combustion gas sent to the combustion chamber 53 through the combustion gas supply line 6 and then burns in the combustion chamber 53. The exhaust gas after combustion in the combustion chamber 53 passes through the exhaust gas discharge line 8 and is discharged to the outside of the engine system 2.

[0016] (Supercharger) FIG. 2 is a schematic cross-sectional view along the axis of the supercharger in an embodiment of the present disclosure. FIG. 3 is a schematic cross-sectional view along the axis on the compressor side of the supercharger in an embodiment of the present disclosure. In the illustrated embodiment, the supercharger 3 includes a turbine 33 driven by the energy of the exhaust gas (exhaust) discharged from the engine 5, a compressor 32 that compresses the combustion gas (e.g., air) supplied to the engine 5, and a rotating shaft 31. The compressor 32 includes a compressor impeller 4 provided in the combustion gas supply line 6 described above, and a compressor housing 34 that rotatably houses the compressor impeller 4. The compressor impeller 4 is mechanically connected to one side of the rotating shaft 31. The turbine 33 includes a turbine blade 35 provided in the exhaust gas discharge line 8 described above, and a turbine housing 36 that rotatably houses the turbine blade 35. The turbine blade 35 is mechanically connected to the other side of the rotating shaft 31.

[0017] The combustion gas that has passed through the compressor impeller 4 of the compressor 32 is guided to the combustion chamber 53 of the engine 5 through the combustion gas supply line 6 and is used for combustion in the combustion chamber 53. The exhaust gas generated by the combustion in the combustion chamber 53 is guided to the turbine blade 35 of the turbine 33 through the exhaust gas discharge line 8. The supercharger 3 is configured to rotate the turbine blade 35 by the energy of the exhaust gas discharged from the engine 5. Since the compressor impeller 4 is mechanically connected to the turbine blade 35 via the rotating shaft 31, the compressor impeller 4 rotates in conjunction with the rotation of the turbine blade 35. The supercharger 3 is configured to compress the combustion gas passing through the compressor impeller 4 by the rotation of the compressor impeller 4, increase the density of the combustion gas, and send it to the engine 5.

[0018] As shown in Figure 2, the supercharger 3 further includes a bearing 37 that rotatably supports the rotating shaft 31 between the compressor impeller 4 and the turbine blades 35, and a bearing base 38 that is positioned between the compressor housing 34 and the turbine housing 36 and supports the bearing 37. The compressor housing 34 has a gas introduction channel forming section 342 that extends along the axial direction of the rotating shaft 31 and forms a gas introduction channel 341 for guiding combustion gas into the compressor housing 34, and a scroll channel forming section 344 that is provided on the outer circumference side of the compressor impeller 4 and forms a spiral scroll channel 343 that extends along the circumferential direction of the rotating shaft 31. The turbine housing 36 is provided on the outer circumference of the turbine blades 35 and includes a scroll channel forming section 362 that forms a spiral-shaped scroll channel 361 extending along the circumferential direction of the rotating shaft 31, and an exhaust gas discharge channel forming section 364 that extends along the axial direction of the rotating shaft 31 and forms an exhaust gas discharge channel 363 for discharging exhaust gas that has passed through the turbine blades 35.

[0019] (Measuring instruments installed in the engine system) In engine system 2, the inlet pressure Ps of the compressor impeller 4, the pressure Pd of the combustion gas (working fluid of the compressor impeller 4) downstream of the intercooler 7 in the combustion gas supply line 6, and the rotational speed N of the supercharger 3 are generally measured. Here, the inlet pressure Ps of the compressor impeller 4 is the pressure of the combustion gas (working fluid of the compressor impeller 4) upstream of the compressor impeller 4 in the combustion gas supply line 6.

[0020] As shown in Figure 1, the engine system 2 includes a first pressure measuring device (in the illustrated example, a pressure sensor) 21 configured to measure the inlet pressure Ps of the compressor impeller 4, a second pressure measuring device (in the illustrated example, a pressure sensor) 22 configured to measure the pressure Pd of the working fluid of the compressor impeller 4, and a first rotational speed measuring device (in the illustrated example, a rotational speed sensor) 25 configured to measure the rotational speed N of the supercharger 3. As shown in Figure 3, the supercharger 3 includes at least one temperature measuring device (in the illustrated example, a temperature sensor) 40 (40A, 40B, 40C, 40D) configured to measure the metal temperature Tm of the compressor impeller 4.

[0021] The control device 11 described above receives measurement results from the first pressure measuring device 21, the second pressure measuring device 22, the first rotational speed measuring device 25, and at least one temperature measuring device 40 (40A, 40B, 40C, 40D).

[0022] (Method for evaluating the remaining lifespan of a compressor impeller) Figure 4 is a flowchart of a method for evaluating the remaining life of a compressor impeller according to one embodiment of the present disclosure. A compressor impeller remaining life evaluation method 1 according to several embodiments includes a rotational speed acquisition step S1, a stress calculation step S2, a metal temperature measurement step (S3), and a remaining life evaluation step S5, as shown in Figure 4. In the illustrated embodiments, several steps in the remaining life evaluation method 1 (such as the stress calculation step S2 and the remaining life evaluation step S5) are performed by a control device 11. In other words, the control device 11 is configured to perform the stress calculation step S2 and the remaining life evaluation step S5, and is configured to perform these steps. Note that some steps in the remaining life evaluation method 1 may be performed by devices or equipment other than the control device 11, or may be performed manually.

[0023] In one embodiment, a 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, remaining life evaluation step S5, etc.) in place of the control device 11, and is configured to perform the above steps. Measurement data from the engine system 2 (measurement results from the first pressure measuring device 21, the second pressure measuring device 22, the first rotational speed measuring device 25, and at least one temperature measuring device 40) are sent to the remaining life evaluation device. The remaining life evaluation device may be located in a remote location away from the control device 11. Specifically, if the engine system 2 including the control device 11 is installed on a ship, the remaining life evaluation device may be located at the same location as the control device 11 on the ship, or at a different location on the ship. Alternatively, the remaining life evaluation device may be located in a facility on land away from the ship. According to the remaining life evaluation device, the remaining life of the compressor impeller 4 can be evaluated even in a remote location away from the engine system 2 including the control device 11.

[0024] In the rotational speed acquisition step S1, the rotational speed N of the supercharger 3 is acquired. In the illustrated embodiment, in the rotational speed acquisition step S1, the measured value of the rotational speed of the supercharger 3 measured by the first rotational speed measuring device 25 is acquired as the rotational speed N of the supercharger 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 supercharger 3 obtained in rotational speed acquisition step S1. Specifically, prior to stress calculation step S2, a first relationship information R1 is obtained that shows the relationship between the stress σ generated in the compressor impeller 4 and the rotational speed N of the supercharger 3. In stress calculation step S2, the stress σ is calculated from the rotational speed N based on the first relationship information R1 obtained in advance.

[0026] The first relational information R1 shows the correspondence between the stress σ generated in the compressor impeller 4 and the rotational speed N of the supercharger 3. It is sufficient if, when the rotational speed N is taken as input information, the stress σ corresponding to the input rotational speed N is obtained as output information. The first relational information R1 may include lists, tables, maps, functions, machine learning models, etc., that show the correspondence between the above input information and the above output information. The first relational information R1 may be created based on steady-state test data, or it may be created based on past performance values, 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 supercharger 3. Therefore, as the rotational speed N increases, the stress σ increases. From the above, it can be said that there is a correlation between stress σ and rotational speed N. The first relationship information R1 includes the above correlation between stress σ and rotational speed N.

[0028] In the metal temperature measurement step S3, the metal temperature Tm of the compressor impeller 4 is measured. In the illustrated embodiment, the measured value of the metal temperature Tm of the compressor impeller 4 measured by at least one temperature measuring device 40 in the metal temperature measurement step S3 is acquired as the metal temperature Tm of the compressor impeller 4. At least one temperature measuring device 40 is configured to acquire the metal temperature Tm without contacting the compressor impeller 4. The installation location and number of temperature measuring devices 40 used to measure the metal temperature Tm of the compressor impeller 4 in the metal temperature measurement step S3 are arbitrary and are not limited to the descriptions of the temperature measuring devices 40 (40A, 40B, 40C, 40D) described later. Furthermore, the measurement location of the metal temperature Tm of the compressor impeller 4 by the temperature measuring device 40 is not limited to the descriptions of the measurement locations of the temperature measuring devices 40 (40A, 40B, 40C, 40D) described later.

[0029] In the remaining life evaluation step S5, the remaining life of the compressor impeller 4 is evaluated using the stress σ calculated in the stress calculation step S2 and the metal temperature Tm measured in the metal temperature measurement step S3, utilizing the relationship between stress σ, metal temperature Tm, and life in the compressor impeller 4 that was acquired in advance.

[0030] Depending on the history of stress σ and metal temperature Tm in the compressor impeller 4 up to the present, damage (such as creep damage) may occur and progress in the compressor impeller 4. According to the compressor impeller remaining life evaluation method 1, in the remaining life evaluation step S5, by utilizing the relationship 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 present can be determined from the stress σ calculated in the stress calculation step S2 and the metal temperature Tm measured in the metal temperature measurement step S3, thus enabling an accurate evaluation of the remaining life of the compressor impeller 4. In particular, evaluating the remaining life using the measured value of the metal temperature Tm that was actually measured allows for a more accurate evaluation of the remaining life of the compressor impeller 4 compared to using an estimated value of the metal temperature Tm estimated from other parameters.

[0031] (Shape of the compressor impeller) In some embodiments, as shown in Figure 3, the compressor impeller 4 described above includes a hub 41 having a hub surface 42 and a back surface 43, and at least one blade 44 provided on the hub surface 42. The back surface 43 extends from an inner circumferential end 432 connected to a projection 45 that protrudes further axially towards the rear end of the compressor impeller 4 than the back surface 43, to an outer circumferential end 431 of the back surface.

[0032] In the illustrated embodiment, the projection 45 is integrally formed with the compressor impeller 4. The projection 45 has an outer surface 451 extending along the axial direction of the compressor impeller 4, and a contact surface 452 that is connected to the rear end of the outer surface 451 in the axial direction and extends along the radial direction of the compressor impeller 4. The front end of the outer surface 451 in the axial direction is connected to the inner circumferential end 432 of the back surface 43. At least a portion of the contact surface 452 contacts a rotor 49 which is positioned adjacent to the rear end of the compressor impeller 4 in the axial direction relative to the projection 45. The rotor 49 has an outer surface 491 extending along the axial direction of the compressor impeller 4. The rotor 49 may be integrally formed with the rotating shaft 31, or it may be formed separately from the rotating shaft 31. In some other embodiments, the projection 45 may be formed separately from the compressor impeller 4. For example, the protruding portion 45 may be a sleeve through which the rotating shaft 31 is inserted.

[0033] In some embodiments, the metal temperature measurement step S3 described above measures the metal temperature Tm at at least one of the following five locations: the outer peripheral edge 46, the inner peripheral edge 47 of the back surface 43, the central portion 48 located between the outer peripheral edge 46 and the inner peripheral edge 47 of the back surface 43, the outer peripheral edge 421 of the hub surface 42, or the outer peripheral edge 441 of the wing surface of the at least one wing 44 described above.

[0034] In the radial direction of the compressor impeller 4, the radial position of the inner circumferential end 432 of the back surface 43 is defined as 0%, and the radial position of the outer circumferential end 431 of the back surface 43 is defined as 100%. The back surface 43 in the radial range of 80% to 100% is defined as the outer circumferential edge 46 of the back surface 43, the back surface 43 in the radial range of 0% to 20% is defined as the inner circumferential edge 47 of the back surface 43, and the back surface 43 in the radial range of more than 20% but less than 80% is defined as the central part 48 of the back surface 43. Furthermore, the hub surface 42 in the radial range of 80% to 100% described above is defined as the outer circumferential edge 421 of the hub surface 42. Furthermore, the blade surface of the blade 44 in the radial range of 80% to 100% described above is defined as the outer circumferential edge 441 of the blade surface. In addition, in the radial direction of the compressor impeller 4, instead of defining the radial position of the inner circumferential end 432 of the back surface 43 as 0%, either the radial position of the outer surface 451 of the protrusion 45 or the radial position of the outer surface 491 of the rotor 49 may be defined as 0%.

[0035] In the illustrated embodiment, at least one of the following is performed by the first temperature measuring device 40A: measurement of the metal temperature Tm of the outer peripheral edge 421 of the hub surface 42, or measurement of the metal temperature Tm of the outer peripheral edge 441 of the blade surface. The compressor housing 34 further has a shroud portion 346 including a shroud surface 345 that faces at least one blade 44 of the compressor impeller 4 across a gap. In the embodiment shown in Figure 3, the gas introduction channel forming portion 342 and the shroud portion 346 are integrally formed, and an annular or arc-shaped gap portion 347 extending along the circumferential direction of the rotating shaft 31 is formed between them and the scroll channel forming portion 344. The first temperature measuring device 40A is installed on the shroud surface 345 that faces the outer peripheral edge 421 of the shroud portion 346 across a gap.

[0036] The metal temperature Tm of the outer peripheral edge 46 of the back surface 43 is measured by a second temperature measuring device 40B. The second temperature measuring device 40B is installed on the opposing surface 381 of the bearing base 38, separated from the outer peripheral edge 46 by a gap. The metal temperature Tm of the inner peripheral edge 47 of the back surface 43 is measured by a third temperature measuring device 40C. The third temperature measuring device 40C is installed on the opposing surface 381 of the bearing base 38, separated from the inner peripheral edge 47 by a gap. The metal temperature Tm of the central part 48 of the back surface 43 is measured by a fourth temperature measuring device 40D. The fourth temperature measuring device 40D is installed on the opposing surface 381 of the bearing base 38, separated from the central part 48 by a gap.

[0037] The critical areas in the compressor impeller 4 that are prone to fatigue damage may differ for each supercharger 3, as they depend on the shape and operating conditions of the compressor impeller 4. Generally, the outer circumference of the hub 41, where the temperature is relatively high, and the boss area, where the stress is relatively high, are likely to be the critical areas. According to the above method, by evaluating the remaining life using the measured metal temperature Tm of the outer circumference 46 of the back surface 43, the outer circumference 421 of the hub surface 42, or the outer circumference 441 of the blade surface, the remaining life of the compressor impeller 4 can be evaluated accurately, especially when the outer circumference of the hub 41 is the critical area. Furthermore, by evaluating the remaining life using the measured metal temperature Tm of the inner circumference 47 of the back surface 43, the remaining life of the compressor impeller 4 can be evaluated accurately, especially when the boss area of ​​the hub 41 is the critical area. Furthermore, by using the measured metal temperature Tm of the central part 48 of the back surface 43, one of the five locations mentioned above, the remaining lifespan of the compressor impeller 4 can be evaluated with relatively high accuracy, not only when the critical location is either the outer circumference or the boss of the hub 41, but also when the critical location is unknown.

[0038] In some embodiments, the metal temperature measurement step S3 described above measures the metal temperature Tm at one of five locations: the outer peripheral edge 46, inner peripheral edge 47, central portion 48 of the back surface 43, the outer peripheral edge 421 of the hub surface 42, or the outer peripheral edge 441 of the blade surface. The compressor impeller remaining life evaluation method 1 described above further includes a critical location estimation step S4 for estimating critical locations that are prone to fatigue damage in the compressor impeller 4. The remaining life evaluation step S5 described above includes a metal temperature calculation step S50 that calculates the metal temperature Tm2 of the critical location from the metal temperature Tm1 measured in the metal temperature measurement step S3, using the relationship between the metal temperature Tm1 at the measurement location where the metal temperature Tm is measured in the metal temperature measurement step S3 and the metal temperature Tm2 of the critical location, which has been acquired in advance.

[0039] In this embodiment, the remaining life of the compressor impeller 4 at a critical location is evaluated. In the stress calculation step S2 of this embodiment, the stress σ generated at the critical location of the compressor impeller 4 is calculated from the rotational speed N of the supercharger 3 obtained in the rotational speed acquisition step S1. That is, the first relationship information R1 of this embodiment shows the correspondence between the stress σ generated at the critical location of the compressor impeller 4 and the rotational speed N of the supercharger 3. In some other embodiments, the stress calculation step S2 described above may be used to calculate the stress σ generated at the measurement location of the compressor impeller 4 from the rotational speed N of the supercharger 3 obtained in the rotational speed acquisition step S1. The first relationship information R1 of this embodiment may show the correspondence between the stress σ generated at the measurement location of the compressor impeller 4 and the rotational speed N of the supercharger 3.

[0040] The estimation of critical areas in the critical area estimation step S4 may be based on steady-state test data, or on past performance values, experimental values, numerical analysis results, etc., other than steady-state test data. The critical area estimation step S4 may also be performed by the control device 11 or the remaining life evaluation device described above. The critical area estimation step S4 is performed before the metal temperature calculation step S50.

[0041] Prior to the metal temperature calculation step S50, the second relationship information R2 is obtained. The second relationship information R2 shows the correspondence between the metal temperature Tm1 at the measurement location and the metal temperature Tm2 at the critical location. It is sufficient if, when the metal temperature Tm1 at the measurement location is used as input information, the metal temperature Tm2 at the critical location corresponding to the input information Tm1 can be obtained as output information. The second relationship information R2 may include lists, tables, maps, functions, machine learning models, etc., that show the correspondence between the above input information and the above output information. The second relationship information R2 may be created based on steady-state test data, or it may be created based on past performance values, experimental values, numerical analysis results, etc., other than steady-state test data.

[0042] In the remaining life evaluation step S5, the metal temperature Tm2 of the critical area is generally used, but if the measurement location is a critical area, the metal temperature Tm1 of the measurement location may be used. In the remaining life evaluation step S5, the remaining life of the compressor impeller 4 may be evaluated using the stress σ calculated in the stress calculation step S2 and the metal temperature Tm2 calculated in the metal temperature calculation step S50, by utilizing the relationship between the stress σ, metal temperature Tm(Tm2), and life of the compressor impeller 4 that was acquired in advance.

[0043] According to the method described above, by including a critical location estimation step S4 and a metal temperature calculation step S50, the metal temperature Tm2 of the critical location can be calculated from the metal temperature Tm1 of the measurement location measured in the metal temperature measurement step S3. By evaluating the remaining life using the metal temperature Tm2 of the critical location, the remaining life of the compressor impeller 4 at the critical location can be evaluated with high accuracy.

[0044] In some other embodiments, the remaining life evaluation step S5 described above may not include the metal temperature calculation step S50. In this case, the remaining life evaluation step S5 may utilize the previously acquired relationship between stress σ, metal temperature Tm (Tm1), and life in the compressor impeller 4 to evaluate the remaining life of the compressor impeller 4 from the stress σ calculated in the stress calculation step S2 and the metal temperature Tm1 measured in the metal temperature measurement step S3.

[0045] In some embodiments, the compressor impeller remaining life evaluation method 1 described above includes the critical location estimation step S4 described above. In the metal temperature measurement step S3 described above, the metal temperature Tm1 is measured at one of the five locations closest to the critical location: the outer peripheral edge 46, inner peripheral edge 47, central portion 48 of the back surface 43, the outer peripheral edge 421 of the hub surface 42, or the outer peripheral edge 441 of the blade surface described above.

[0046] According to the method described above, the remaining life of the compressor impeller 4 at the critical location can be evaluated with relatively high accuracy by using the metal temperature Tm1 of the single location closest to the critical location estimated in the critical location estimation step S4. Furthermore, it is not necessary to install temperature measuring devices 40 to measure the metal temperature Tm1 at locations other than the single location closest to the critical location.

[0047] In some embodiments, the metal temperature measurement step S3 described above is performed at one of the following locations: the outer peripheral edge 46 of the back surface 43, the outer peripheral edge 421 of the hub surface 42, or the outer peripheral edge 441 of the wing surface, and the inner peripheral edge 47 of the back surface 43.

[0048] According to the above method, the remaining life can be evaluated using the metal temperature Tm1 measured at any of the outer peripheral edge 46 of the back surface 43, the outer peripheral edge 421 of the hub surface 42, or the outer peripheral edge 441 of the blade surface, and the remaining life can also be evaluated using the metal temperature Tm1 measured at the inner peripheral edge 47 of the back surface 43. In this case, the remaining life of the compressor impeller 4 can be evaluated with relatively high accuracy not only when the critical location is either the outer peripheral edge or the boss portion of the hub 41, but also when the critical location is unknown.

[0049] (Allowable operating time of the compressor impeller) In some embodiments, as shown in Figure 4, the remaining life evaluation step S5 described above includes a Larson-Miller parameter calculation step S51 which calculates the Larson-Miller parameter LMP from the stress σ calculated in the stress calculation step S2, using the relationship between the stress σ in the compressor impeller 4 and the Larson-Miller parameter LMP (third relationship information R3) obtained in advance, and an allowable operating time calculation step S52 which calculates the allowable operating time tr of the compressor impeller 4 from the Larson-Miller parameter LMP calculated in the Larson-Miller parameter calculation step S51 and the metal temperature Tm measured in the metal temperature measurement step S3. The allowable operating time tr of the compressor impeller 4 indicates the time until the compressor impeller 4, subjected to a constant stress σ at a constant metal temperature Tm, breaks.

[0050] Prior to the Larson-Miller parameter calculation step S51, a third relationship information R3 is obtained. The third relationship information R3 shows the correspondence between the stress σ in the compressor impeller 4 and the Larson-Miller parameter LMP. It is sufficient if, when the stress σ is used as input information, the Larson-Miller parameter LMP corresponding to the input information stress σ is obtained as output information. The third relationship information R3 may include lists, tables, maps, functions, machine learning models, etc., that show the correspondence between the above input information and the above output information. The third relationship information R3 may be created based on steady-state test data, or it may be created based on past performance values, experimental values, numerical analysis results, etc., other than steady-state test data.

[0051] Figure 5 is an explanatory diagram illustrating the relationship between stress and Larson-Miller parameters in a compressor impeller. Figure 5 shows a graph with stress σ in the compressor impeller 4 on the vertical axis and Larson-Miller parameter LMP on the horizontal axis. Figure 5 shows a master curve M1 that illustrates the relationship between stress σ and Larson-Miller parameter LMP. Master curve M1 can be obtained, for example, from the results of creep rupture tests at several stress levels σ and metal temperature Tm. The third relationship information R3 includes master curve M1. In one embodiment, in Larson-Miller parameter calculation step S51, the Larson-Miller parameter LMP corresponding to the stress σ is calculated from the stress σ calculated in stress calculation step S2, based on master curve M1.

[0052] In the allowable operating time calculation step S52, the allowable operating time tr of the compressor impeller 4 is calculated based on the Larson-Miller parameter LMP calculated in the Larson-Miller parameter calculation step S51 and the metal temperature Tm measured in the metal temperature measurement step S3, using the following formula (1). LMP=Tm×(C+log(tr))······(1) Here, LMP is the Larson-Miller parameter, Tm is the metal temperature of the compressor impeller 4, C is the material constant, and tr is the allowable operating time of the compressor impeller 4. In this embodiment, the material constant C = 20.

[0053] According to the above method, by using the Larson-Miller parameter LMP, the allowable operating time tr of the compressor impeller 4, considering the creep damage to the compressor impeller 4 up to the present time, can be determined from the stress σ calculated in the stress calculation step S2 and the metal temperature Tm measured in the metal temperature measurement step S3. The allowable operating time tr of the compressor impeller 4 calculated in the remaining life evaluation step S5 (S51 and S52) allows for an accurate evaluation of the remaining life of the compressor impeller 4.

[0054] In the allowable operating time calculation step S52, the metal temperature Tm used to calculate the allowable operating time tr may be the metal temperature Tm1 at the measurement location measured in the metal temperature measurement step S3, or the metal temperature Tm2 at the critical location calculated in the metal temperature calculation step S50. In order to evaluate the remaining life of the compressor impeller 4 at the critical location, it is preferable that the metal temperature Tm used to calculate the allowable operating time tr in the allowable operating time calculation step S52 is the metal temperature Tm2 at the critical location.

[0055] In some embodiments, the allowable operating time calculation step S52 described above calculates the allowable operating time tr of the compressor impeller 4 from the Larson-Miller parameter LMP calculated in the Larson-Miller parameter calculation step S51 and the metal temperature Tm1 at the measurement position measured in the metal temperature measurement step S3.

[0056] In addition, in some other embodiments, the allowable operating time calculation step S52 described above calculates the allowable operating time tr of the compressor impeller 4 from the Larson-Miller parameter LMP calculated in the Larson-Miller parameter calculation step S51 and the metal temperature Tm2 of the critical area calculated in the metal temperature calculation step S50. In this case, by calculating the allowable operating time tr using the metal temperature Tm2 of the critical area, the remaining life of the compressor impeller 4 at the critical area can be evaluated with high accuracy.

[0057] Furthermore, in some of the embodiments described above, the allowable operating time tr of the compressor impeller 4 is determined from the stress σ and metal temperature Tm using the Larson-Miller parameter LMP. However, the allowable operating time tr of the compressor impeller 4 may also be determined from the stress σ and metal temperature Tm (Tm1 or Tm2) using other known extrapolation methods.

[0058] (Supercharger rotation speed) Figure 6 is a flowchart of the rotational speed acquisition step in one embodiment of the present disclosure. If the engine system 2 described above does not include the first rotational speed measuring device 25 described above, which is configured to measure the rotational speed N of the supercharger 3, then it is necessary to determine the rotational speed N of the supercharger 3. In some embodiments, as shown in Figure 6, the rotational speed acquisition step S1 described above includes a pressure ratio acquisition step S11, a flow rate acquisition step S12, and a rotational speed calculation step S13.

[0059] 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 for measuring the inlet pressure Ps of the compressor impeller 4, an outlet pressure acquisition step S15 for acquiring the outlet pressure Pe of the compressor impeller 4, and a pressure ratio calculation step S16 for calculating the pressure ratio Pr of the compressor impeller 4 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 acquired in the outlet pressure acquisition step S15.

[0060] In the flow rate acquisition step S12, the flow rate Fr of the compressor impeller 4 is acquired. In the flow rate acquisition step S12, the flow rate Fr of the compressor impeller 4 is estimated using a known method with the engine specifications and parameters that are commonly measured in the engine system 2.

[0061] In the rotational speed calculation step S13, the rotational speed N of the supercharger 3 is 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, using the relationship (fourth relationship information R4) of the compressor impeller 4, which was acquired in advance.

[0062] Prior to the rotational speed calculation step S13, the fourth relationship information R4 is obtained. The fourth relationship information R4 shows the correspondence between the pressure ratio Pr, flow rate Fr of the compressor impeller 4, and the rotational speed N of the supercharger 3. It is sufficient that, when the pressure ratio Pr and flow rate Fr are used as input information, the rotational speed N corresponding to the input information, Pr and flow rate Fr, can be obtained as output information. The fourth relationship information R4 may include lists, tables, maps, functions, machine learning models, etc., that show the correspondence between the above input information and the above output information. The fourth relationship information R4 may be created based on steady-state test data, or it may be created based on past performance values, experimental values, numerical analysis results, etc., other than steady-state test data.

[0063] According to the above method, by utilizing the relationship between the pressure ratio Pr, flow rate Fr, and rotational speed N of the compressor impeller 4, 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 above method, even if the engine system 2 is not equipped with a rotational speed measuring device to measure the rotational speed N of the turbocharger 3, the remaining life evaluation method 1 of the compressor impeller 4 can be performed.

[0064] In some embodiments, as shown in Figure 6, the pressure ratio acquisition step S11 described above includes the inlet pressure measurement step S14 described above, the outlet pressure acquisition step S15 described above, and the pressure ratio calculation step S16 described above.

[0065] According to the above method, 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 above method, even if the engine system 2 is not equipped with a pressure ratio measuring device to measure the pressure ratio Pr of the compressor impeller 4, the remaining life evaluation method 1 of the compressor impeller 4 can be performed.

[0066] In some embodiments, as shown in Figure 6, the rotational speed acquisition step S1 described above includes a pressure ratio acquisition step S11, a flow rate acquisition step S12, and a rotational speed calculation step S13, and the pressure ratio acquisition step S11 described above includes the inlet pressure measurement step S14 described above, the outlet pressure acquisition step S15 described above, and the pressure ratio calculation step S16 described above. In the outlet pressure acquisition step S15 described above, the outlet pressure Pe is obtained by adding the pressure loss ΔP caused by the intercooler 7 to the pressure Pd of the working fluid of the compressor impeller 4 measured downstream of the intercooler 7.

[0067] 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 (working fluid of the compressor impeller 4) downstream of the compressor impeller 4 and upstream of the intercooler 7 in the combustion gas supply line 6. Due to the pressure loss ΔP in the intercooler 7, the pressure Pd of the combustion gas downstream of the intercooler 7 is lower than the outlet pressure Pe of the compressor impeller 4.

[0068] In the illustrated embodiment, in the outlet pressure acquisition step S15, the pressure Pd measured by the second pressure measuring device 22 is added to the pressure loss ΔP generated by the intercooler 7 to obtain the outlet pressure Pe. The pressure loss ΔP is preset before the outlet pressure acquisition step S15 based on the specifications of the intercooler 7.

[0069] According to the above method, in the outlet pressure acquisition step S15, the outlet pressure Pe of the compressor impeller 4 can be accurately estimated by adding the pressure loss ΔP caused by the intercooler 7 to the pressure Pd of the working fluid of the compressor impeller 4 downstream of the intercooler 7. This allows for accurate estimation of the pressure ratio Pr of the compressor impeller 4 in the pressure ratio calculation step S16. Furthermore, according to the above method, the pressure ratio Pr of the compressor impeller 4 can be estimated using the pressure Pd of the working fluid of the compressor impeller 4 downstream of the intercooler 7, which is commonly measured in engine systems 2 equipped with a supercharger 3, and the inlet pressure Ps of the compressor impeller 4. According to the above method, even if the engine system 2 is not equipped with a pressure measuring device to measure the outlet pressure Pe of the compressor impeller 4 or a pressure ratio measuring device to measure the pressure ratio Pr of the compressor impeller 4, the remaining life evaluation method 1 of the compressor impeller 4 can be performed. The estimation of the outlet pressure Pe in the pressure ratio acquisition step S11, the pressure ratio calculation step S16, the flow rate acquisition step S12, and the rotational speed calculation step S13 may be performed by the control device 11 or the remaining life evaluation device described above.

[0070] This disclosure is not limited to the embodiments described above, but also includes modified forms of the embodiments described above, as well as forms that combine these forms as appropriate.

[0071] The contents described in some of the embodiments above can be understood, for example, as follows:

[0072] 1) A compressor impeller remaining life evaluation method (1) according to at least one embodiment of the present disclosure is: A method (1) for evaluating the remaining lifespan of a compressor impeller (4) of a supercharger (3), wherein The rotational speed acquisition step (S1) is to acquire the rotational speed (N) of the supercharger (3), A stress calculation step (S2) is performed to calculate the stress (σ) generated in the compressor impeller (4) from the rotational speed (N) of the supercharger (3) obtained in the rotational speed acquisition step (S1), A metal temperature measurement step (S3) for measuring the metal temperature (Tm) of the compressor impeller (4), The system includes a remaining life evaluation step (S5) which evaluates 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) measured in the metal temperature measurement step (S3), using the relationship between stress (σ), metal temperature (Tm), and life of the compressor impeller (4) that has been acquired in advance.

[0073] Depending on the history of stress (σ) and metal temperature (Tm) in the compressor impeller (4) up to the present, damage (such as creep damage) may occur and progress in the compressor impeller (4). According to the method described in 1) above, in the remaining life evaluation step (S5), by utilizing the relationship 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 present can be determined from the stress (σ) calculated in the stress calculation step (S2) and the metal temperature (Tm) measured in the metal temperature measurement step (S3), thus enabling an accurate evaluation of the remaining life of the compressor impeller (4). In particular, evaluating the remaining life using the measured value of the metal temperature (Tm) that was actually measured allows for a more accurate evaluation of the remaining life of the compressor impeller (4) compared to using an estimated value of the metal temperature (Tm) estimated from other parameters.

[0074] 2) In some embodiments, the remaining life evaluation method (1) for the compressor impeller described in 1) above, The compressor impeller (4) is A hub (41) having a hub surface (42) and a back surface (43), and at least one wing (44) provided on the hub surface (42), The rear surface (43) extends from the inner circumferential end (432) connected to the projection (45) that protrudes further from the rear end in the axial direction of the compressor impeller (4) than the rear surface (43) to the outer circumferential end (431) of the rear surface (43), In the aforementioned metal temperature measurement step (S3), The metal temperature (Tm) is measured at at least one of the following five locations: the outer peripheral edge (46) or inner peripheral edge (47) of the back surface (43), the central portion (48) located between the outer peripheral edge (46) and the inner peripheral edge (47) of the back surface (43), the outer peripheral edge (421) of the hub surface (42), or the outer peripheral edge (441) of the wing surface of the at least one wing (44).

[0075] The critical areas in the compressor impeller (4) that are prone to fatigue damage may differ from one supercharger (3) to another, depending on the shape and operating conditions of the compressor impeller (4). Generally, the outer circumference of the hub (41), where the temperature is relatively high, and the boss area, where the stress is relatively high, are likely to be the critical areas. According to the method in 2) above, the remaining life can be evaluated using the measured metal temperature (Tm) of the outer circumference (46) of the back surface (43), the outer circumference (421) of the hub surface (42), or the outer circumference (441) of the blade surface, among the five locations mentioned above. In particular, the remaining life of the compressor impeller (4) can be evaluated accurately when the outer circumference of the hub (41) is the critical area. Furthermore, by evaluating the remaining life using the measured metal temperature (Tm) of the inner peripheral edge (47) of the back surface (43) among the five locations mentioned above, the remaining life of the compressor impeller (4) can be evaluated with high accuracy, especially when the boss portion of the hub (41) is the critical location. Additionally, by evaluating the remaining life using the measured metal temperature (Tm) of the central portion (48) of the back surface (43) among the five locations mentioned above, the remaining life of the compressor impeller (4) can be evaluated with relatively high accuracy not only when the critical location is either the outer peripheral or boss portion of the hub (41), but also when the critical location is unknown.

[0076] 3) In some embodiments, the remaining life evaluation method (1) for the compressor impeller described in 2) above, In the aforementioned metal temperature measurement step (S3), The metal temperature (Tm) is measured at any one of the following five locations: the outer peripheral edge (46), the inner peripheral edge (47), the central portion (48) of the back surface (43), the outer peripheral edge (421) of the hub surface (42), or the outer peripheral edge (441) of the wing surface of at least one wing (44). The method (1) for evaluating the remaining life of the compressor impeller is as follows: The system further includes a critical location estimation step (S4) for estimating critical locations in the compressor impeller (4) that are prone to fatigue-related damage, The remaining life evaluation step (5) is, The process includes a metal temperature calculation step (S50) which utilizes the relationship between the metal temperature (Tm1) at the measurement position where the metal temperature (Tm) is measured in the metal temperature measurement step (S3) and the metal temperature (Tm2) at the critical location, obtained in advance, to calculate the metal temperature (Tm2) at the critical location from the metal temperature (Tm1) at the measurement position measured in the metal temperature measurement step (S3). Using the relationship between stress (σ), metal temperature (Tm), and lifespan in the compressor impeller (4), the remaining lifespan of the compressor impeller (4) is evaluated from the stress (σ) calculated in the stress calculation step (S2) and the metal temperature (Tm2) calculated in the metal temperature calculation step (S50).

[0077] According to the method described in 3) above, by including a critical location estimation step (S4) and a metal temperature calculation step (S50), the metal temperature of the critical location (Tm2) can be calculated from the metal temperature (Tm1) measured at the measurement location in the metal temperature measurement step (S3). By evaluating the remaining life using the metal temperature (Tm2) of the critical location, the remaining life of the compressor impeller (4) at the critical location can be evaluated with high accuracy.

[0078] 4) In some embodiments, the remaining life evaluation method (1) for the compressor impeller described in 2) above, The system further includes a critical location estimation step (S4) for estimating critical locations in the compressor impeller (4) that are prone to fatigue-related damage, In the aforementioned metal temperature measurement step (S3), The metal temperature (Tm1) is measured at one of the five locations closest to the critical location: the outer peripheral edge (46), the inner peripheral edge (47), the central portion (48) of the back surface (43), the outer peripheral edge (421) of the hub surface (42), or the outer peripheral edge (441) of the wing surface of at least one wing (44).

[0079] According to the method described in 4) above, the remaining life can be evaluated with relatively high accuracy by using the metal temperature (Tm1) of the single location closest to the critical location estimated in the critical location estimation step (S4).

[0080] 5) In some embodiments, the remaining life evaluation method (1) for the compressor impeller described in 2) above, In the aforementioned metal temperature measurement step (S3), The metal temperature (Tm1) is measured at one of the following locations: the outer peripheral edge (46) of the back surface (43), the outer peripheral edge (421) of the hub surface (42), or the outer peripheral edge (441) of the wing surface of at least one wing (44), and the inner peripheral edge (47) of the back surface (43).

[0081] According to the method described in 5) above, the remaining life can be evaluated using the metal temperature (Tm1) measured at any of the outer peripheral edge (46) of the back surface (43), the outer peripheral edge (421) of the hub surface (42), or the outer peripheral edge (441) of the blade surface, and the remaining life can also be evaluated using the metal temperature (Tm1) measured at the inner peripheral edge (47) of the back surface (43). In this case, the remaining life of the compressor impeller (4) can be evaluated with relatively high accuracy not only when the critical area is either the outer peripheral edge or the boss portion of the hub (41), but also when the critical area is unknown.

[0082] 6) In some embodiments, the remaining life evaluation method (1) for a compressor impeller described in any of 1) to 5) above, The aforementioned remaining life evaluation step (S5) is, A Larson-Miller parameter calculation step (S51) is performed to calculate the Larson-Miller parameter (LMP) from the stress (σ) calculated in the stress calculation step (S2) by utilizing the relationship between the stress (σ) in the compressor impeller (4) and the Larson-Miller parameter (LMP) obtained in advance, The method includes an allowable operating time calculation step (S52) which calculates the allowable operating time (tr) of the compressor impeller (4) from the Larson-Miller parameter (LMP) calculated in the Larson-Miller parameter calculation step (S51) and the metal temperature (Tm) measured in the metal temperature measurement step (S3).

[0083] According to the method described in 6) above, by using the Larson-Miller parameter (LMP), the allowable operating time (tr) of the compressor impeller (4), taking into account the creep damage to the compressor impeller (4) up to the present time, can be determined from the stress (σ) calculated in the stress calculation step (S2) and the metal temperature (Tm) measured in the metal temperature measurement step (S3). The allowable operating time (tr) of the compressor impeller (4) calculated in the remaining life evaluation step (S5) allows for an accurate evaluation of the remaining life of the compressor impeller (4).

[0084] 7) In some embodiments, the compressor impeller remaining life evaluation method (1) described in 6) above, The compressor impeller (4) is A hub (41) having a hub surface (42) and a back surface (43), and at least one wing (44) provided on the hub surface (42), The rear surface (43) extends from the inner circumferential end (432) connected to the projection (45) that protrudes further from the rear end in the axial direction of the compressor impeller (45) than the rear surface (43) to the outer circumferential end (431) of the rear surface (43), In the aforementioned metal temperature measurement step (S3), The metal temperature (Tm) is measured at any one of the following five locations: the outer peripheral edge (46), the inner peripheral edge (47), the central portion (48) of the back surface (43), the outer peripheral edge (421) of the hub surface (42), or the outer peripheral edge (441) of the wing surface of at least one wing (44). The method (1) for evaluating the remaining life of the compressor impeller is as follows: The system further includes a critical location estimation step (S4) for estimating critical locations in the compressor impeller (4) that are prone to fatigue-related damage, The remaining life evaluation step (5) is, The process includes a metal temperature calculation step (S50) which utilizes the relationship between the metal temperature (Tm1) at the measurement position where the metal temperature (Tm) is measured in the metal temperature measurement step (S3) and the metal temperature (Tm2) at the critical location, obtained in advance, to calculate the metal temperature (Tm2) at the critical location from the metal temperature (Tm1) at the measurement position measured in the metal temperature measurement step (S3). In the allowable operating time calculation step (S52), the allowable operating time (tr) of the compressor impeller (4) is calculated from the Larson-Miller parameter (LMP) calculated in the Larson-Miller parameter calculation step (S51) and the metal temperature (Tm2) of the critical area calculated in the metal temperature calculation step (S50).

[0085] According to the method described in 7) above, the remaining lifespan of the compressor impeller (4) at the critical point can be accurately evaluated by calculating the allowable operating time (tr) using the metal temperature (Tm2) at the critical point. [Explanation of symbols]

[0086] 1. Method for evaluating the remaining lifespan of a compressor impeller. 2. Engine System 3. Supercharger 4 Compressor impeller 5 Engine 6. Combustion gas supply line 7. Intercooler 8. Exhaust gas discharge line 9. Fuel Injector 11 Control device 21. First pressure measuring device 22. Second pressure measuring device 25 First rotational speed measuring device 31 Rotating shaft 32 Compressors 33 Turbine 34 Compressor Housing 35 Turbine blades 36 Turbine Housing 40,40A~40D Temperature measuring device 51 Cylinder 52 pistons 53 Combustion chamber C material constant Fr flow rate LMP Larson-Miller parameters M1 Master Curve N rotational speed Pd pressure PE outlet pressure Pr pressure ratio Ps Inlet Pressure R1, R2, R3, R4 Relationship Information S1 Rotation speed acquisition step S2 Stress Calculation Step S3 Metal temperature measurement step S4 Critical Location Estimation Step S5 Remaining Life Assessment Step S11 Pressure ratio acquisition step S12 Flow rate acquisition step S13 Rotation speed calculation step S14 Inlet pressure measurement step S15 Outlet pressure acquisition step S16 Pressure ratio calculation step S50 Metal Temperature Calculation Step S51 Larson-Miller parameter calculation step S52 Allowable Operating Time Calculation Step Tm, Tm1, Tm2 Metal temperature tr Allowable operating time

Claims

1. A method for evaluating the remaining lifespan of a compressor impeller in a supercharger, wherein the remaining lifespan of the compressor impeller is evaluated, A rotational speed acquisition step to acquire the rotational speed of the supercharger, A stress calculation step which calculates the stress generated in the compressor impeller from the rotational speed of the supercharger obtained in the rotational speed acquisition step, A metal temperature measurement step for measuring the metal temperature of the compressor impeller, A remaining life evaluation step is performed to evaluate the remaining life of the compressor impeller using the relationship between stress, metal temperature, and lifespan obtained in advance, based on the stress calculated in the stress calculation step and the metal temperature measured in the metal temperature measurement step. A method for evaluating the remaining lifespan of a compressor impeller equipped with [a specific feature / feature].

2. The compressor impeller is, A hub having a hub surface and a back surface, and at least one wing provided on the hub surface, The aforementioned back surface extends from its inner circumferential end, which is connected to a projection that protrudes further towards the rear end in the axial direction of the compressor impeller than the aforementioned back surface, to its outer circumferential end. In the aforementioned metal temperature measurement step, The metal temperature is measured at at least one of the following five locations: the outer peripheral edge of the back surface, the inner peripheral edge, the central portion located between the outer peripheral edge and the inner peripheral edge of the back surface, the outer peripheral edge of the hub surface, or the outer peripheral edge of the wing surface of at least one of the wings. A method for evaluating the remaining lifespan of a compressor impeller according to claim 1.

3. In the aforementioned metal temperature measurement step, The metal temperature is measured at one of the following five locations: the outer peripheral edge, the inner peripheral edge, the central portion of the back surface, the outer peripheral edge of the hub surface, or the outer peripheral edge of the wing surface of at least one wing. The method for evaluating the remaining life of the compressor impeller is as follows: The system further includes a critical location estimation step for estimating critical locations in the compressor impeller that are prone to fatigue-related damage, The aforementioned remaining life evaluation step is: The process includes a metal temperature calculation step that utilizes the relationship between the metal temperature at the measurement position and the metal temperature at the critical location, which was previously obtained in the metal temperature measurement step, to calculate the metal temperature at the critical location from the metal temperature at the measurement position measured in the metal temperature measurement step. Using the relationship between stress, metal temperature, and lifespan in the compressor impeller, the remaining lifespan of the compressor impeller is evaluated from the stress calculated in the stress calculation step and the metal temperature calculated in the metal temperature calculation step. The method for evaluating the remaining lifespan of a compressor impeller according to claim 2.

4. The system further includes a critical location estimation step for estimating critical locations in the compressor impeller that are prone to fatigue-related damage, In the aforementioned metal temperature measurement step, The metal temperature is measured at one of the five locations—the outer peripheral edge, the inner peripheral edge, the central portion of the back surface, the outer peripheral edge of the hub surface, or the outer peripheral edge of the wing surface of at least one wing—that is closest to the critical location. The method for evaluating the remaining lifespan of a compressor impeller according to claim 2.

5. In the aforementioned metal temperature measurement step, The metal temperature is measured at one of the following locations: the outer peripheral edge of the back surface, the outer peripheral edge of the hub surface, or the outer peripheral edge of the wing surface of at least one wing, and the inner peripheral edge of the back surface. The method for evaluating the remaining lifespan of a compressor impeller according to claim 2.

6. The aforementioned remaining life evaluation step is: A Larson-Miller parameter calculation step that calculates the Larson-Miller parameter from the stress calculated in the stress calculation step, using the relationship between the stress in the compressor impeller and the Larson-Miller parameter obtained in advance, The method includes a step to calculate the allowable operating time of the compressor impeller from the Larson-Miller parameter calculated in the Larson-Miller parameter calculation step and the metal temperature measured in the metal temperature measurement step, A method for evaluating the remaining life of a compressor impeller according to any one of claims 1 to 5.

7. The compressor impeller is, A hub having a hub surface and a back surface, and at least one wing provided on the hub surface, The aforementioned back surface extends from its inner circumferential end, which is connected to a projection that protrudes further towards the rear end in the axial direction of the compressor impeller than the aforementioned back surface, to its outer circumferential end. In the aforementioned metal temperature measurement step, The metal temperature is measured at one of the following five locations: the outer peripheral edge of the back surface, the inner peripheral edge, the central portion located between the outer peripheral edge and the inner peripheral edge of the back surface, the outer peripheral edge of the hub surface, or the outer peripheral edge of the wing surface of at least one wing. The method for evaluating the remaining life of the compressor impeller is as follows: The system further includes a critical location estimation step for estimating critical locations in the compressor impeller that are prone to fatigue-related damage, The aforementioned remaining life evaluation step is: The process includes a metal temperature calculation step that utilizes the relationship between the metal temperature at the measurement position and the metal temperature at the critical location, which was previously obtained in the metal temperature measurement step, to calculate the metal temperature at the critical location from the metal temperature at the measurement position measured in the metal temperature measurement step. In the allowable operating time calculation step, the allowable operating time of the compressor impeller is calculated from the Larson-Miller parameter calculated in the Larson-Miller parameter calculation step and the metal temperature of the critical area calculated in the metal temperature calculation step. A method for evaluating the remaining lifespan of a compressor impeller according to claim 6.

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