JP6402551B2 - Turbocharger fatigue failure diagnosis method and turbocharger fatigue failure diagnosis device - Google Patents

Description

  The present invention relates to a turbocharger fatigue failure diagnosis method and a turbocharger fatigue failure diagnosis device, and more specifically, the number of inflection points of the rotational speed of a turbocharger stored in a storage device is reduced and the capacity is small. The present invention relates to a turbocharger fatigue failure diagnosis method and a turbocharger fatigue failure diagnosis device that can make use of the rainflow method in a storage device and can accurately diagnose a fatigue failure of a turbocharger.

  Changes in the rotational speed of the turbocharger mounted on the vehicle may rise from a low rotation to a high rotation at once, if it falls a little on the way and then rises again, and may rise and fall in small increments. Very diverse.

  Therefore, in order to diagnose a fatigue failure in a turbocharger, the rotational speed of the turbocharger is measured, the cycle count is performed based on the inflection point of the rotational speed, and the fatigue value accumulated in the turbocharger is calculated. ing.

  In this connection, although it is not a method of diagnosing a fatigue failure of a turbocharger, all data obtained by sampling the engine speed and fuel injection amount over a certain period of time are obtained using the rainflow method. There has been proposed a method of diagnosing engine fatigue failure by performing cycle counting (see, for example, Patent Document 1).

  This method memorizes inflection points of about 720,000 times in about two hours, and diagnoses fatigue errors that are theoretically accurate by the rainflow method. Similarly to this method, the inflection point of the rotation speed of the turbocharger is stored in the storage device, the cycle count is performed by the rain flow method, and the fatigue failure of the turbocharger is diagnosed from the fatigue value based on the cycle count. It is possible.

  However, since the rainflow method is a data analysis method by post-processing, it is necessary to store inflection points of the rotational speeds of all the turbochargers in operation in a storage device. In order to store all the inflection points of the rotational speed of the turbocharger, an infinite storage area must be secured in the storage device for an uncertain period from the start to the stop of the engine. For this reason, securing a corresponding storage area in an actual on-vehicle computer causes an increase in cost.

Japanese Patent Application Laid-Open No. 11-211622

  The present invention has been made in view of the above problems, and the problem is that the number of inflection points of the rotational speed of the turbocharger stored in the storage device is reduced, so that even a storage device with a small capacity can perform rainflow. The present invention is to provide a turbocharger fatigue failure diagnosis method and a turbocharger fatigue failure diagnosis apparatus that can accurately diagnose a fatigue failure of a turbocharger by utilizing the method.

The turbocharger fatigue failure diagnosis method of the present invention for solving the above-mentioned problems is obtained by sequentially acquiring the inflection points of the rotation speed of the turbocharger and storing them in a storage device, based on the stored inflection points. In the method for diagnosing a fatigue failure of the turbocharger, the rotational speed of the inflection point is compared with a threshold value set in the vicinity of a lower limit rotational speed preset in the turbocharger, and at least three of the variable The inflection point at the start point and the end point is less than or equal to the threshold value, and one interval where the rotation speed at the other inflection points is greater than the threshold value is set in the interval. The cycle count of the section is performed by the rainflow method, the section fatigue value of the section is calculated based on the cycle count, stored in the storage device, and the previous time stored in the storage device Adding the section fatigue value of the section to the cumulative fatigue value up to the section, calculating the cumulative fatigue value up to the section and storing it in the storage device, the cumulative fatigue value and a preset fatigue limit value; , And diagnosing a fatigue failure of the turbocharger.

In addition, a turbocharger fatigue failure diagnosis apparatus of the present invention for solving the above-described problems includes an inflection point acquiring means for sequentially acquiring an inflection point of the rotational speed of the turbocharger, and a memory for storing the inflection point. An apparatus and a calculation unit that performs determination and calculation based on the inflection point, and the calculation unit diagnoses a fatigue failure of the turbocharger based on the inflection point stored in the storage device The calculation unit determines whether the rotation speed of the inflection point is equal to or less than a threshold value set in the vicinity of a lower limit rotation speed preset in the turbocharger, and has at least three inflection points. And setting one section in which the rotational speed of the inflection point at the start point and the end point is less than or equal to the threshold value, and the rotational speed of the other inflection points is greater than the threshold value. Cycle of the section The section fatigue value of the section is calculated based on the cycle count and stored in the storage device. The accumulated fatigue value up to the previous section stored in the storage device is added to the section fatigue value of the section. A cumulative fatigue value up to the interval is calculated by adding the values, and the cumulative fatigue value is compared with a preset fatigue limit value to diagnose a fatigue failure of the turbocharger. Is.

  According to the turbocharger fatigue failure diagnosis method and the turbocharger fatigue failure diagnosis apparatus of the present invention, a minute section sandwiched when the rotational speed of the inflection point is equal to or lower than a threshold is divided, and Since the cycle count is performed by the flow method, the number of inflection points stored in the storage device can be reduced. This makes it possible to accurately diagnose a fatigue failure of a turbocharger using a rainflow method even with a storage device having a small capacity.

  Further, after the cycle count is performed, the stored inflection point can be erased, so that the capacity of the storage device necessary for diagnosing a fatigue failure of the turbocharger can be reduced, and the cost can be reduced.

  In addition, since the section fatigue value is calculated for each minute section based on the rainflow method, it is possible to improve the accuracy of turbocharger fatigue failure diagnosis while ensuring real-time performance and to reduce the cumulative fatigue value of the turbocharger. By diagnosing a fatigue failure of the turbocharger without evaluating it, it is possible to determine an appropriate replacement time for the turbocharger.

It is explanatory drawing which illustrates embodiment of the fatigue failure diagnostic apparatus of the turbocharger of this invention. It is a flowchart which illustrates embodiment of the fatigue failure diagnostic method of the turbocharger of this invention. It is an example of the historical data of the inflection point memorize | stored in the memory | storage device of FIG. It is explanatory drawing which showed the relationship between the elapsed time of the historical data of FIG. 2, and a rotational speed. It is an example of the fatigue value map memorize | stored in the memory | storage device of FIG. It is an example of the data of the fatigue value in each stress fluctuation | variation of the area memorize | stored in the memory | storage device of FIG. It is an example of the data of the section fatigue value and the cumulative fatigue value in each section memorize | stored in the memory | storage device of FIG. It is another example of the history data of the inflection point memorize | stored in the memory | storage device of FIG. It is a flowchart which shows an example which made the flowchart of FIG. 2 more detailed. 10 is a flowchart following A in FIG. 9. It is a flowchart following B of FIG. It is a flowchart following C in FIG.

  DESCRIPTION OF EMBODIMENTS Embodiments of a turbocharger fatigue failure diagnosis method and a turbocharger fatigue failure diagnosis device of the present invention will be described below. FIG. 1 shows a configuration of a fatigue failure diagnosis apparatus 20 for a turbocharger 11 according to an embodiment of the present invention.

  The fatigue failure diagnosis device 20 diagnoses a fatigue failure of a turbocharger 11 provided in a diesel engine (hereinafter, engine) 10. In the engine 10, air taken into the intake passage 12 during traveling of the vehicle is compressed by the compressor 11 a of the turbocharger 11 to become high temperature, cooled by the intercooler 13, and then taken as intake air 14 as intake air. And then supplied to the engine body 15. The intake air supplied to the engine body 15 is mixed with fuel and burned to generate thermal energy, and then becomes exhaust gas and is exhausted from the exhaust manifold 16 to the exhaust passage 17. The exhaust gas is purified by the exhaust gas purification device 18 after being driven by the turbine 11b of the turbocharger 11 and released to the atmosphere. Further, the exhaust gas is mixed with the intake air from the EGR passage 19 having the EGR valve 19a and the EGR cooler 19b.

  The fatigue failure diagnosis apparatus 20 provided in the engine 10 includes an inlet pressure sensor 21, an outlet pressure sensor 22, an intake air amount sensor 23, a storage device 24, and a calculation unit 25.

The inlet pressure sensor 21, the outlet pressure sensor 22, and the intake air amount sensor 23 are provided as a part of the inflection point acquisition unit for the turbocharger rotation speed, and estimate the turbocharger rotation speed (hereinafter referred to as the rotation speed). It is a sensor. The inlet pressure sensor 21, the outlet pressure sensor 22, and the intake air amount sensor 23 are connected to the calculation unit 25, and the detection values of the inlet pressure sensor 21, the outlet pressure sensor 22, and the intake air amount sensor 23 are the calculation unit 25. Sent to. The computing unit 25 estimates the rotational speed of the turbocharger 11 with reference to these detected values and a rotational speed map in which the rotational speed of the turbocharger 11 is set based on the intake air amount and the pressure ratio of the compressor 11a. To do. Then, the time t _x and the rotation speed N _x of the inflection point P _x which is the apex when the estimated turbocharger rotation speed changes from increase to decrease or from decrease to increase are acquired. And stored in the storage device 24.

  Instead of estimating the rotation speed of the turbocharger 11 from the detection values of the inlet pressure sensor 21, the outlet pressure sensor 22, and the intake air amount sensor 23, a rotation sensor that detects the rotation speed of the turbocharger 11 may be used. .

The storage device 24 is a device that can store data such as the inflection point P _x (t _x , N _x ) and the calculation result calculated by the calculation unit 25 in each storage area. Arranged in the computer 26. The storage device 24 has a storage area inflection point P _x is stored, and its storage area two points or more, it is capable of storing the inflection point P _x less than one thousand points.

The calculation unit 25 includes an inlet pressure sensor 21, an outlet pressure sensor 22, and an intake air amount sensor 23.
As an apparatus for determining the turbocharger rotation speed estimated from the detected value of the engine and storing the inflection point P _x in the storage device 24 or performing the determination and calculation based on the data stored in the storage device 24, the engine 10 is arranged in an electronic computer 26 of a vehicle on which 10 is mounted.

In such a fatigue failure diagnosis device 20 of the turbocharger 11, as shown in FIG. 2, the calculation unit 25 is a turbocharger estimated from detection values of the inlet pressure sensor 21, the outlet pressure sensor 22, and the intake air amount sensor 23. Step S10 for sequentially acquiring the inflection point P ₁ to the inflection point P _x based on the rotation speed, and Step S20 for storing the inflection point P ₁ to the inflection point P _x in the storage area of the storage device 24. Is going.

Then, the arithmetic unit 25 compares the inflection point _{P 1} ~ inflection point _{P x} rotational speed _{N x} and the threshold value _{N 0} that is set in the vicinity of the preset lower limit speed _{N min} turbocharger 11 , starting at an inflection point P ₁ which becomes a threshold value N ₀ or less, it is performed step S30 for setting the threshold value N ₀ inflection point P _x which falls below the one segment S _y that is an end point to the next.

Then, the arithmetic unit 25, a step S40 to perform the cycle count interval S _y by rain flow method with respect to the section S _y, calculates and stores device section fatigue value .SIGMA.F _y of the section S _y on the basis of the cycle count 24 is stored in step S50.

Then, the arithmetic unit 25 adds the interval fatigue value .SIGMA.F _y of the section _{S y} to the cumulative fatigue value TTLF _y-1 up to the previous interval _{S y-1} stored in the storage device 24, to the segment _{S y} Step S70 for calculating the cumulative fatigue value TTLF _y and storing it in the storage device 24, and comparing the cumulative fatigue value TTLF _y with a preset fatigue limit value α for diagnosing a fatigue failure of the turbocharger 11 And go.

  Details of this fatigue failure diagnosis method will be described with reference to FIGS.

In step S10, the calculation unit 25 performs the inflection point P ₁ (t ₁ , N ₁₎ based on the estimated values estimated from the detected values sent from the inlet pressure sensor 21, the outlet pressure sensor 22, and the intake air amount sensor 23. ) To inflection points P _x (t _x , N _x ) are acquired. Next, in step S _<b > 20, the calculation unit 25 sequentially stores the inflection point P ₁ (t ₁ , N ₁ ) to the inflection point P _x (t _x , N _x ) in the storage area of the storage device 24. For example, in step S10 and step S20, as shown in FIG. 3, it is sequentially stored from the inflection point _{P 1} to the inflection point _{P 13.} In addition, each inflection point P _x is not occurring at regular intervals. Each time t _x indicates the time when the inflection point P _x occurs.

Then, in step S30, the arithmetic unit 25 compares the threshold value N ₀ that is set in the vicinity of the lower limit speed N _min of the rotational speed N _x and turbocharger 11 of the inflection point P _x stored in the storage device 24 sets the interval _{S y,} separated each time the rotational speed _{N x} of the inflection point _{P x} is the threshold _{N 0} or less.

The lower limit rotational speed _Nmin is set to the rotational speed of the turbocharger 11 when the engine rotational speed obtained in advance through experiments or the like is the idle rotational speed. Therefore, the lower limit rotational speed N _min varies depending on the engine 10 configuration and the turbocharger 11 configuration.

The threshold N ₀ is set to a rotation speed at which the number of inflection points P _{1 to} P _x in the section S _y is 3 or more and less than 1000. When this threshold N ₀ is less than 1.1 times the lower limit rotational speed N _min , the number of inflection points P _{1 to} P _x in the section S _y increases, and the storage area of the storage device 24 becomes insufficient. On the other hand, if the threshold N ₀ is four times greater than the lower limit speed N _min is the rotational speed N _x is the stress variation of the low-speed side is not reflected, the accuracy of the interval fatigue value .SIGMA.F _y decreases. Therefore,
The threshold N ₀ is preferably 1.1 times or more and 4 times or less of the lower limit rotation speed N _min , and more preferably 1.2 times or more and 3 times or less.

For example, as shown in FIG. 3, since the rotational speeds N ₁ and N ₁₃ are equal to or less than the threshold value N _0, the section S ₂ is set with the inflection point P ₁ as the start point and the inflection point P ₁₃ as the end point.

Then, as the step S40, it performs a cycle count interval S _y by rain flow method based on the inflection point P _x in processor 25 segment S _y. The Rain flow method analysis of this section _{S y,} one stress variation SF _z generated in the interval _{S y} are at least are counted, and the maximum rotational speed _{N MaxZ} of the stress variation SF _z, and the amplitude _{L z,} as the number of cycles 0.5 or 1.0 is counted.

For example, as illustrated in FIG. 4, the calculation unit 25 analyzes that the stress fluctuations of the stress fluctuations SF ₁ to SF ₇ have occurred in the section S ₂ by the rainflow method. Stress variation SF ₁ is made from the inflection point _{P 1} to the inflection point _{P 6,} the maximum rotational speed _{N 6,} the amplitude _{L 1 (N} 6 -N 1) and cycle number 0.5. Further, the stress variation SF ₂ becomes halfway (rotational speed becomes _{N 2} position) of the inflection point _{P 2} from the inflection point _{P 3} and the inflection point _{P 4,} the maximum rotational speed _{N 2,} the amplitude _L 2 ( the N ₂ -N ₃₎ and cycle number 1.0. Similarly, stress fluctuation SF ₃ to stress fluctuation SF ₇ are calculated. In FIG. 4, an arrow indicating one direction indicates a cycle number of 0.5, and an arrow indicating both directions indicates a cycle number of 1.0.

Next, as step S <b> 50, the calculation unit 25 calculates the fatigue value F _z of each stress variation SF _z with reference to the fatigue value map M <b> 1 stored in the storage device 24, and stores it in the storage device 24. Next, the computing unit 25 calculates the section fatigue value ΣF _y of the section S _y by accumulating the fatigue values F _z and stores them in the storage device 24.

The fatigue value map M1 is a map fatigue value _{F z} cycle number 1.0 based on the maximum rotational speed _{N MaxZ} and amplitude _{L z} of the stress variation SF _z is set. The fatigue value F _z of the turbocharger 11 increases _{exponentially} when the maximum rotational speed N _maxz of the stress fluctuation SF _z is high and the amplitude L _z is large.

For example, As shown in FIG. 5, referring to fatigue value map M1, the maximum rotational speed _{N 6} and the amplitude _{L 1} Metropolitan Stress variations SF _1, the stress variation SF ₁ cycle number 1.0 minutes fatigue value 2F ₁ Is calculated. The stress variation SF ₁ is 0.5 cycles, fatigue value _{F 1} of the stress variation SF ₁ is calculated by multiplying the fatigue value map M1 fatigue value 2F ₁ to 0.5 calculated from. Hereinafter, similarly to the fatigue value _{F 2} from the stress variation SF ₂ to stress variations SF ₇ to fatigue value _{F 7} is calculated. From the stress variation SF ₁ of the section _{S 2} to the stress variation SF ₇ is, as shown in FIG. 6, it is stored in the storage device 24.

Then, by integrating the fatigue value _F 1 to F _7, calculates an interval fatigue value .SIGMA.F ₂ of section _{S 2.}

Then, in step S60, the arithmetic unit 25 adds the interval fatigue value .SIGMA.F _y of the cumulative fatigue value TTLF _y-1 and segment _{S y} up interval _{S y-1} up to the previous cumulative up interval _{S y} The fatigue value TTLF _y is calculated and stored in the storage device 24.

For example, as shown in FIG. 7, the accumulated fatigue value up interval _{S 1} TTLF ₁ a section fatigue value of the interval _{S 1} .SIGMA.F _1, and the accumulated fatigue value up section _{S 2} TTLF ₂ cumulative fatigue value up interval _{S 1} A value obtained by adding the section fatigue value ΣF ₂ (= F ₁ + F ₂ +... + F ₇ ) of the section S ₂ to TTLF ₁ .

Next, in step S70, the computing unit 25 compares the cumulative fatigue value TTLF _y with a predetermined fatigue limit value α to diagnose a fatigue failure of the turbocharger 11. The diagnosis of the fatigue failure is made by diagnosing that the turbocharger 11 may be subject to a fatigue failure when the cumulative fatigue value TTLF _y exceeds the fatigue limit value α.

  In addition, when the arithmetic unit 25 diagnoses that the turbocharger 11 may have a fatigue failure, it is preferable to warn the driver by a warning device 27 such as a warning buzzer or a warning lamp. Further, the fatigue limit value α is a value determined in advance by experiments or the like, and is determined by the capacity of the turbocharger 11 or the like.

According to the fatigue failure diagnosis apparatus 20 and the fatigue failure diagnostic method of the turbocharger 11, delimiting the rotation speed N _x is the threshold N ₀ minute interval S _y sandwiched upon reaching the following inflection point P _x, since the cycle count by rain flow method for the segment S _y, it can be reduced the number of inflection points P ₁ to P _x stored in the storage device 24. As a result, the fatigue failure of the turbocharger 11 can be diagnosed with high accuracy using the rainflow method even in the storage device 24 having a small capacity.

In addition, after the cycle count is performed, the stored inflection points P _{1 to} P _x-1 can be deleted. Thereby, the capacity | capacitance of the memory | storage device 24 required in order to diagnose the fatigue failure of the turbocharger 11 can be reduced, and cost can be reduced.

In addition, since the section fatigue value ΣF _y is calculated for each minute section S _y based on the rainflow method, the accuracy of diagnosis of fatigue failure of the turbocharger 11 can be improved while securing the real-time property, and the turbocharger 11. By diagnosing the fatigue failure of the turbocharger 11 without underestimating the cumulative fatigue value TTLF _y , it is possible to determine an appropriate replacement time for the turbocharger 11.

Additionally, although in standard rain flow method eliminates the time axis, since the calculated interval fatigue value .SIGMA.F _y based on the rain flow method per minute interval S _y, chronological accumulation of fatigue of the turbocharger 11 It is also possible to make a judgment. This leads to the identification of the cause when momentary damage is given to the turbocharger 11.

In the fatigue failure diagnosis apparatus 20 and the fatigue failure diagnosis method, the threshold N ₀ is set to a rotational speed at which the number of inflection points P _{1 to} P _x in the section S _y is 3 or more and 250 or less. It is more desirable to set. As a result, the storage area of the storage device 24 can be further reduced, which is advantageous for cost reduction.

In the fatigue failure diagnosis apparatus 20 and the fatigue failure diagnosis method described above, when all of the inflection point of the segment falls below the threshold value N ₀ is the interval fatigue value in that section, it is desirable not to store.

As shown in FIG. 8, the section between the section S ₄ and the section S ₅ all inflection point is below the threshold value N _0. Since it is clear that the section fatigue value in this section can be ignored by looking at the fatigue value map M1, it is not stored in the storage device 24.

Further, in the fatigue failure diagnosis apparatus 20 and the fatigue failure diagnosis method described above, the inflection point P ₁ in the section S _y from which the section fatigue value ΣF _y is calculated from the storage device 24 to the inflection point before the inflection point P _x is obtained. It is desirable to erase up to point P _x-1 .

In the fatigue failure diagnosis apparatus 20 and the fatigue failure diagnosis method, the section S _y may be set simultaneously with the acquisition of the inflection point P _x .

The flowcharts shown in FIGS. 9 to 12 are examples in which the flowchart of FIG. 2 is more detailed. In FIG. 9, step S110 and step S120 correspond to step S10 and step S20 in FIG. Further, step S130 to step S160 in FIG. 9 correspond to step S30 in FIG. This step S130~ step S160, the setting of the interval _{S y} can be performed simultaneously with the acquisition of the inflection point _{P x,} it is advantageous for reducing the storage area of more storage devices 24.

  In FIG. 10, step S170 corresponds to step S40 of FIG. Further, step S180 to step S250 in FIG. 10 correspond to step S50 in FIG.

  In FIG. 11, step S280 and step S290 in FIG. 11 correspond to step S60 in FIG. Further, step S300 in FIG. 11 corresponds to step S70 in FIG.

In FIG. 11, as step S _<b > 260, the calculation unit 25 deletes the inflection point excluding the inflection point P _x of the section S _y from the storage area of the storage device 24. Inflection point P _x is the end point of the interval S _y without erasing there is a possibility that the start point of the next segment S _{y + 1,} erasing the remaining inflection point P ₁ ~P _x-1.

  In FIG. 12, the start point of the next section is set by performing steps S310 to S350.

If an inflection point (new P ₂ ) exceeding the threshold value N ₀ appears next to the inflection point (new P ₁ ) as the end point after performing steps S310 to S340, the process returns to D in FIG. for example, in the case of end point of the section S ₄ of FIG. 8, then the end point of the value of the section S ₄ to the start of the S ₅ as a small section is not used. After becoming the end point becomes the threshold N ₀ or less, although the inflection point of the threshold N ₀ or less may become the starting point of the next small section, of the starting point for further next inflection point This is a case where (new P ₂ ) exceeds the threshold value N ₀ . The inflection point P _x while not exceeding the threshold value N ₀ is always overwritten as the inflection point P ₁ , and when the next inflection point P ₂ exceeds the threshold value N ₀ , the inflection point P ₁ is a new minute value. Adopted as the start point of the section.

For example, in FIG. 3, to erase from the inflection point _{P 1} to the inflection point _{P 12,} the inflection point _{P 1} comprising a point of inflection _{P 13} as the starting point of the next segment _{S 3.} Although the end point P _x of the section S ₄ of FIG. 8 is a candidate for the starting point of the section S _5, when the subsequent inflection point continues below the threshold are always new inflection starting point of the candidate interval S ₅ Overwritten with dots. While repeating this, when it is detected that the inflection point P _{x + 1} exceeds the threshold, the inflection point P _x becomes the start point P ₁ of the next minute section S ₅ .

In this way, by using the rainflow method for each section S _y , it is possible to delete the inflection point P ₁ to the inflection point P _{x−1 of} the section S _y where the section fatigue value ΣF _y is calculated. Sequentially erases the from the inflection point P ₁ of the segment S _y that interval fatigue value .SIGMA.F _y is calculated to the inflection point P _x-1, can be reduced storage area of the storage unit 24 required for fatigue diagnostics.

Further, the erasing from the inflection point _{P 1} of the segment _{S y} to the inflection point _{P x-1,} it is preferable that erasing data in the stress variation SF _z interval _{S y.} By erasing the data of the stress fluctuation SF _z , it is advantageous for reducing the storage area of the storage device 24.

According to the flowchart of FIGS. 9-12, the storage area of the storage device 24, becomes only and the interval S _y and the section fatigue value .SIGMA.F _y and accumulated fatigue value TTLF _y shown in FIG. 7 are sequentially stored, a storage device This is advantageous in reducing the storage area of 24.

  In addition, the structure of the engine 10 of said embodiment is an example, and this invention is not limited to this. For example, it may be applied to a gasoline engine.

Further, in the above embodiments, an example has been described for calculating the fatigue value F _z of the stress variation SF _z with fatigue value map M1, the present invention is not limited thereto. For example, an SN diagram of the turbocharger 11 may be used instead of the fatigue value map M1.

  Further, the electronic computer 26 of the above embodiment may be an ECU that controls the engine 10. In particular, the present invention can reduce the storage area of the storage device 24 necessary for diagnosing a fatigue failure of the turbocharger 11, so that the storage area of the ECU in which a wide variety of data is stored is not compressed.

DESCRIPTION OF SYMBOLS 10 Engine 11 Turbocharger 11a Compressor 11b Turbine 20 Fatigue failure diagnosis device 21 Inlet pressure sensor 22 Outlet pressure sensor 23 Intake air amount sensor 24 Storage device 25 Calculation unit 26 Computer M1 Fatigue value map N ₀ threshold N _min lower limit rotational speed N _x Rotational speed P _x Inflection point S _y section TTLF _y cumulative fatigue value ΣF _y section fatigue value α fatigue limit value

Claims (5)

In a method for sequentially acquiring an inflection point of the rotational speed of a turbocharger and storing it in a storage device, and diagnosing a fatigue failure of the turbocharger based on the stored inflection point,
The rotation speed of the inflection point is compared with a threshold value set in the vicinity of a lower limit rotation speed preset in the turbocharger, and has at least three inflection points. One rotation speed of the point is equal to or less than the threshold value, and one section where the rotation speed of the other inflection points is larger than the threshold value ,
The cycle count of the section is performed by the rainflow method on the section, the section fatigue value of the section is calculated based on the cycle count, and stored in the storage device.
The cumulative fatigue value up to the previous section stored in the storage device is added to the section fatigue value of the section, the cumulative fatigue value up to the section is calculated and stored in the storage device, the cumulative fatigue value And a fatigue limit value set in advance for diagnosing the fatigue failure of the turbocharger.   The turbocharger fatigue failure diagnosis method according to claim 1, wherein the threshold is set to a rotational speed at which the number of inflection points in the section is 3 or more and less than 1,000.   The turbocharger fatigue failure diagnosis method according to claim 1 or 2, wherein the section from the start point to the inflection point before the end point of the section in which the section fatigue value is calculated from the storage device is deleted. Counting at least one stress variation generated in the section by the rainflow method, calculating the amplitude of the stress variation, the maximum rotation speed and the number of cycles,
With reference to the fatigue value map in which the fatigue value at the number of cycles of the stress variation is set based on the amplitude and the maximum rotation speed of the stress variation, the fatigue value of each stress variation in the section is calculated,
The turbocharger fatigue failure diagnosis method according to claim 1, wherein all the fatigue values in the section are integrated to calculate the section fatigue value. An inflection point acquiring means for sequentially acquiring an inflection point of the rotation speed of the turbocharger, a storage device for storing the inflection point, and a calculation unit for performing determination and calculation based on the inflection point; In an apparatus for diagnosing a fatigue failure of the turbocharger based on the inflection point stored in the storage device by an arithmetic unit,
The calculation unit determines whether the rotation speed of the inflection point is equal to or less than a threshold value set in the vicinity of a lower limit rotation speed preset in the turbocharger, and has at least three inflection points. , Setting one section where the rotation speed of the inflection point at the start point and the end point is less than or equal to the threshold value, and the rotation speed of the other inflection points is greater than the threshold value ,
The cycle count of the section is performed by the rainflow method on the section, the section fatigue value of the section is calculated based on the cycle count, and stored in the storage device.
Calculate the cumulative fatigue value up to the section by adding the section fatigue value of the section to the cumulative fatigue value stored in the storage device up to the previous section, and the cumulative fatigue value and a preset fatigue limit value And a turbocharger fatigue failure diagnosis device, characterized in that the fatigue failure of the turbocharger is diagnosed.

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