JP2008008246A - Axial run out abnormality detection device for turbocharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an axial wobbling detection device for a turbocharger avoiding performance degradation of the turbocharger. <P>SOLUTION: This axial wobbling detection device 10 for a turbocharger for detecting axial wobbling of a turbocharger 1 with an electric motor supplying compressed air to an engine with a driving source of exhaust gas pressure of the engine, comprises a gap sensor 12 detecting the distance to the compressor blade of the turbocharger 1 equipped with an electric motor. Whenever the rotational position of the compressor blade comes to a position opposite to the sensor part 13 of the gap sensor 12, the amount of the axial wobbling of the turbocharger 1 equipped with the electric motor is calculated by an axial wobbling amount calculating means 162 based on a variation of the peak value appearing in the output signal of the gap sensor 12, and the axial wobbling amount calculating means 162 judges whether or not the axial wobbling is in an abnormal condition with the axial wobbling amount exceeding a set value. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a turbocharger shaft shake abnormality detecting device that detects a shaft shake abnormality of a turbocharger.

  Conventionally, Patent Document 1 discloses a shaft shake abnormality detection device for a general rotating body. In the shaft shake abnormality detecting device described in Patent Document 1, the amount of shaft shake is detected by a rotary encoder, and when the amount of shaft shake exceeds a set value, it is determined that a shaft shake abnormality state has occurred.

Japanese Patent Laid-Open No. 4-161829

However, a shaft shake abnormality detection device for a turbocharger that supplies compressed air to the engine using the exhaust pressure of the engine as a drive source has not been put into practical use for the following reason. That is, when an attempt is made to detect a shaft shake abnormality of a turbocharger using the shaft shake abnormality detection device described in Patent Document 1, the rotary slit plate constituting the rotary encoder must be attached to the rotating body of the turbocharger. Then, since the turbocharger rotates at a very high speed (for example, about 170,000 rpm), it is not realistic to attach such a rotation slit to the rotating body of the turbocharger because it causes a significant deterioration in performance of the turbocharger. Absent.
SUMMARY OF THE INVENTION An object of the present invention is to provide a turbocharger shaft shake abnormality detecting device that avoids deterioration in performance of a turbocharger.

According to the first aspect of the present invention, the distance from the compressor blade is detected by the gap sensor. Then, a peak value appears in the output signal of the gap sensor that changes with the rotation of the turbocharger every time the rotational position of the compressor blade is opposed to the gap sensor (see, for example, FIG. 2B). When the shaft shake occurs in the turbocharger as exemplified by the dotted lines in FIGS. 3A and 3B, the magnitude of the peak value changes (for example, FIGS. 3B and 3B). c)).
Then, based on the magnitude of the change in the peak value, the shaft shake amount calculation means calculates the shaft shake amount, and the abnormality determination means determines whether or not the shaft shake amount exceeds the set value and the shaft shake is abnormal. Since the determination is made, it is possible to detect the shaft shake abnormality using the gap sensor without attaching the rotating slit described in Patent Document 1 to the rotating body of the turbocharger. Accordingly, it is possible to provide a turbocharger shaft shake abnormality detecting device that avoids deterioration of the performance of the turbocharger.

  According to the second aspect of the present invention, calculating the shaft shake amount based on the difference between the maximum value and the minimum value among a plurality of peak values appearing within a predetermined period is calculated by the shaft shake amount calculating means. A suitable example is given.

  According to a third aspect of the present invention, the shaft shake amount calculating means measures the fluctuation cycle of the peak value, and sets the measured fluctuation cycle as a predetermined period. Therefore, if the invention according to claim 3 is applied when the maximum value or the minimum value among the plurality of peak values appears periodically, the calculation accuracy of the axial shake amount can be improved.

According to the fourth aspect of the present invention, the distance from the compressor blade is detected by the gap sensor, and the analog waveform as the output signal of the gap sensor that changes as the turbocharger rotates is converted into a pulse waveform by the pulse conversion means. (See, for example, FIG. 7). Then, as described above, when the axial fluctuation occurs in the turbocharger, the pulse width changes (for example, see FIG. 8).
Then, based on the change in the pulse width, the shaft shake amount calculating means calculates the shaft shake amount, and the abnormality determining means determines whether or not the shaft shake amount exceeds the set value and the shaft shake is in an abnormal state. Therefore, it is possible to detect the shaft shake abnormality using the gap sensor without attaching the rotating slit described in Patent Document 1 to the rotating body of the turbocharger. Accordingly, it is possible to provide a turbocharger shaft shake abnormality detecting device that avoids deterioration of the performance of the turbocharger.

  According to the fifth aspect of the present invention, calculating the amount of shaft shake based on the difference between the maximum width and the minimum width among the widths of a plurality of pulses appearing within a predetermined period is obtained by calculating the amount of shaft shake by the shaft shake amount calculating means. It is mentioned as a suitable example which calculates.

  According to the sixth aspect of the present invention, the shaft shake amount calculation means measures the fluctuation period of the pulse waveform, and sets the measured fluctuation period as a predetermined period. Therefore, when the maximum value or the minimum value among the widths of the plurality of pulses appear periodically, the calculation accuracy of the axial shake amount can be improved by applying the invention according to claim 6.

  In the seventh aspect of the invention, since the predetermined period is set as the predetermined period, the processing load of the shaft shake amount calculation means can be reduced as compared with the case where the fluctuation period of the peak value or the fluctuation period of the pulse waveform is measured. .

  According to an eighth aspect of the present invention, the turbocharger is a turbocharger with an electric motor that uses an electric motor as a drive source in addition to the exhaust pressure of the engine. Such a turbocharger with an electric motor has to be designed to have a longer rotation shaft than a turbocharger without an electric motor, so that the shaft runout becomes large. Therefore, it is preferable to employ the shaft shake abnormality detecting device according to claims 1 to 7 for the turbocharger with an electric motor in which the problem of shaft runout becomes remarkable.

  According to a ninth aspect of the present invention, there is provided a rotation speed calculation means for calculating the rotation speed of the turbocharger based on the output signal of the gap sensor. Therefore, the gap sensor for calculating the rotational speed of the turbocharger and the gap sensor for detecting the shaft shake abnormality can be used together, so that the number of parts can be reduced.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
A turbocharger shaft shake abnormality detecting device (hereinafter simply referred to as “shaft shake abnormality detecting device”) according to a first embodiment of the present invention will be described with reference to FIGS.
The turbocharger 1 with an electric motor according to the present embodiment is a turbocharger with an electric motor that supplies compressed air to the engine using the exhaust pressure of the engine as a drive source, and uses an electric motor as a drive source in addition to the exhaust pressure of the engine. .

<Configuration of turbocharger with electric motor>
First, the configuration of the turbocharger 1 with an electric motor will be described with reference to FIG.
The turbocharger 1 with an electric motor includes a turbine 4 that is rotationally driven by the exhaust gas flow of the engine, a compressor 5 that is rotationally driven by the rotation of the turbine 4 and pressurizes intake air, and a shaft 6 that connects the turbine 4 and the compressor 5. An induction motor 7 that electrically drives the shaft 6 is configured.

  Further, the housing 2 accommodates a bearing 3 that supports the shaft 6 so as to be rotatable in the radial direction. A gap is formed between the shaft 6 and the bearing 3, and this gap is filled with oil. The shaft 6 is structured to float in the oil.

The turbine 4 includes a turbine wheel 41 having a plurality of turbine blades, and a turbine housing 42 that is a portion of the housing 2 that houses the turbine wheel 41. The compressor 5 includes a compressor wheel 51 having a plurality of (for example, 5 to 12) compressor blades 53 (see FIG. 2A), and a compressor housing 52 that is a portion of the housing 2 that houses the compressor wheel 51. And have.
When the turbine wheel 41 is rotated by the exhaust gas, the compressor wheel 51 is rotated together with the shaft 6, and the air taken into the intake passage in the compressor housing 52 is compressed and sent to the combustion chamber.

  The induction motor 7 includes a rotor 8 fixed to the shaft 6 and a stator 9 fixed to the housing 2 of the turbocharger 1 with electric motor. The stator 9 includes U, V, W, X, Y A six-phase excitation coil (not shown) composed of the Z phase is firmly fixed. The excitation coil of the induction motor 7 is energized and controlled by an electric motor drive unit 18 of an ECU (Electronic Control Unit) 15, whereby the rotational speed of the rotor 8 is controlled. That is, the ECU 15 performs energization control on the six-phase excitation coil to assist control of rotation of the turbocharger 1 with motor.

  Here, the turbocharger 1 with an electric motor rotates in a very wide range from about 10,000 to 20,000 rpm of idling to ultra high speed rotation (for example, about 200,000 rpm) at full load. When only the exhaust gas flow of the engine is used as the drive source of the compressor 5, it takes time until the turbo effect appears even if the accelerator is depressed when the turbocharger 1 with an electric motor is rotating at a low speed (for example, 50000 rpm or less). A turbo lag problem arises. In view of this, the induction motor 7 assists the rotation of the turbocharger 1 with an electric motor during such a low rotation to suppress the turbo lag.

<Axle shake abnormality detection device>
Next, the configuration of the shaft shake abnormality detection device 10 will be described.
The shaft shake abnormality detection device 10 includes the gap sensor 12 that detects the distance from the compressor blade 53 and the ECU 15 described above, and detects shaft shake abnormality and the rotational speed of the turbocharger 1 with an electric motor. That is, the shaft shake abnormality detection device 10 also functions as a rotation speed detection device of the turbocharger 1 with an electric motor.

  The gap sensor 12 includes an eddy current sensor unit 13 and a sensor driver 14. The sensor unit 13 has a coil (not shown) as magnetic field generating means, and is attached to the compressor housing 52 so as to face the compressor blade 53. It is desirable that the distance between the sensor unit 13 and the compressor blade 53 is as close as possible within a range in which the rotation of the compressor blade 53 is not hindered so that the sensor unit 13 can obtain sufficient sensitivity, for example, 0.5 mm to 1 mm. Set to range.

  The sensor driver 14 has a drive circuit that supplies a high-frequency alternating current to the coil of the sensor unit 13. The frequency of the AC exciting current is set to such an extent that it can be detected that each blade 53 passes through the magnetic field generated by the coil of the sensor unit 13 based on the rotation speed of the compressor blade 53. The coil supplied with the AC excitation current generates a magnetic flux in the thickness direction of the compressor housing 52 to form a magnetic field. The sensor driver 14 detects a change in the current flowing through the coil of the sensor unit 13. The sensor driver 14 may be configured integrally with the sensor unit 13 or may be configured separately. Further, the sensor driver 14 may be provided in the ECU 15.

Next, the operation of the abnormality detection device 10 will be described.
Hereinafter, as shown in FIG. 2A, a case where eight compressor blades 53 are attached to the compressor wheel 51 will be described as an example. When the blade 53 approaches or separates from the sensor unit 13 due to the rotation of the compressor wheel 51, the gap sensor 12 outputs a detection signal shown in FIG. That is, every time the rotation position of the compressor blade 53 is opposed to the sensor unit 13 (the position closest to the sensor unit 13), a peak value appears in the output signal (output voltage) of the gap sensor 12.

  More specifically, when the compressor wheel 51 rotates together with the turbine wheel 41, each compressor blade 53 passes through the magnetic field generated by the coil of the sensor unit 13. At this time, an eddy current is generated in each blade 53 so as to cancel the magnetic field generated by the coil. When the strength of the magnetic field generated by the coil changes due to the eddy current generated in each blade 53, the value of the current flowing through the coil of the sensor unit 13 changes. The gap sensor 12 detects that an eddy current is generated in the blade 53 due to a change in the value of the current flowing through the coil.

Using the signal output from the gap sensor 12, the shaft shake amount detection unit 16 of the ECU 15 calculates the shaft shake amount. Then, the abnormality determination unit 17 of the ECU 15 determines whether or not the shaft shake amount calculated by the shaft shake amount detection unit 16 exceeds the set value and is in a shaft shake abnormality state. When the abnormality determining unit 17 determines that the shaft shake is abnormal, the motor driving unit 18 stops driving the induction motor 7.
Further, the ECU 15 calculates the rotation speed of the compressor wheel 51 using the detection signal shown in FIG. 2B output from the gap sensor 12. The ECU 15 that executes the calculation functions as “rotational speed calculation means” recited in the claims.

Next, shaft shake of the turbocharger 1 with an electric motor and a detection method thereof will be described.
As described above, since the shaft 6 has a structure that floats in the oil filled between the bearings 3, the rotating bodies 41, 51, 8 including the turbine wheel 41, the compressor wheel 51, the rotor 8, and the shaft 6. When the rotational balance of 6 is poor, as shown in FIGS. 3A and 3B, the shafts of the rotating bodies 41, 51, 8, and 6 with respect to the housing 2 are generated. 3A and 3B, the solid lines indicate the compressor wheel 51 and the shaft 6 when the shaft is not shaken, and the dotted lines in FIGS. 3A and 3B are when the shaft is shaken. The compressor wheel 51 and the shaft 6 are shown.

  Then, when such a shaft shake of the rotating bodies 41, 51, 8, 6 occurs, the distance between the compressor blade 53 and the sensor unit 13 changes. The output waveform of the gap sensor 12 at this time is a signal whose peak value changes periodically as shown in FIG. If the rotation balance is further lost and the shaft runout becomes larger, the output waveform shown in FIG.

  In the shaft shake abnormality detection method according to the first embodiment, the shaft shake amount detection unit 16 includes a peak detection means 161 and a shaft shake amount calculation means 162 (see FIG. 4). First, the peak detector 161 measures and stores a plurality of peak values appearing in the output voltage of the gap sensor 12. Thereafter, the shaft shake amount calculation means 162 calculates the difference between the maximum peak value and the minimum peak value among the plurality of peak values within the set period as a fluctuation value. For example, in FIG. 3C, the variation value that is the difference between the maximum peak value P1 and the minimum peak value P2 in the predetermined period is L1, and in FIG. 3D, the maximum peak value P3 in the predetermined period is The variation value that is the difference from the minimum peak value P4 is L2.

  The shaft shake amount calculation means 162 calculates the shaft shake amount based on the fluctuation values L1 and L2 related to the peak value. In the first embodiment, as shown in FIG. 5, the fluctuation values L1 and L2 and the amount of shaft shake are regarded as being in a proportional relationship, and the amount of shaft shake is calculated. The shaft shake amount calculation means 162 determines that the calculated shaft shake amount exceeds the set value, indicating that the shaft shake is in an abnormal state, and determines that the abnormal state has not been reached if it does not exceed the set value. To do.

  When the ECU 15 determines that the shaft shake is abnormal by the shaft shake amount calculation unit 162, the ECU 15 controls the motor drive unit 18 to stop driving the induction motor 7. The shaft shake amount calculation means 162 corresponds to “shaft shake amount calculation means” and “abnormality determination means” recited in the claims.

Next, the operation of the ECU 15 that detects shaft shake of the turbocharger 1 with an electric motor as described above will be described with reference to the flowchart of FIG.
First, in step S10, the output voltage from the gap sensor 12 is captured, and in steps S20 and S30, it is determined that the previous voltage is higher than the previous voltage and the current voltage is lower than the previous voltage, and the peak value is detected. To do.
Specifically, the previous output voltage Vo (n−1) is equal to or higher than the previous output voltage Vo (n−2) (S20: Yes), and the current output voltage Vo (n) is the previous output voltage Vo (n). When it is determined that it is lower than (n-1) (S30: Yes), the process proceeds to step S40, and the previous output voltage Vo (n-1) is stored as the voltage Vpk (k) as the peak value. If NO in step S20 or NO in step S30, the process returns to step S10.

Next, the maximum peak is detected and stored in steps S50, S60, and S70.
Specifically, the peak voltage Vpk (k-1) stored last time is equal to or higher than the previous peak voltage Vpk (k-2) (S50: Yes), and the current peak voltage Vpk (k) is the previous peak voltage Vpk. If it is determined that the value is lower than (k-1) (S60: Yes), the process proceeds to step S70, and the previous peak voltage Vpk (k-1) is stored as the maximum peak value Vpmax.

On the other hand, when the previously stored peak voltage Vpk (k-1) is lower than the previous peak voltage Vpk (k-2) (S50: No), the minimum peak is detected and stored in steps S50, S80, and S90.
Specifically, when it is determined that the current peak voltage Vpk (k) is equal to or lower than the previous peak voltage Vpk (k−1) (S80: Yes), the process proceeds to step S90, and the previous peak voltage Vpk (k) k-1) is stored as the minimum peak value Vpmin.
Note that if the determination in step S60 is No or the determination in step S80 is No, the process returns to step S10.

  Next, in step S100, it is determined whether or not the difference between the maximum peak value Vpmax and the minimum peak value Vpmin exceeds the set value Vth. If it is determined that the set value Vth has been exceeded (S100: Yes), it is considered that the shaft shake is in an abnormal state, and the motor drive unit 18 is controlled to stop driving the induction motor 7 in step S110. If it is determined that the set value Vth is not exceeded (S100: No), the process returns to step S10.

As described above, according to the first embodiment, the distance from the compressor blade 53 is detected by the gap sensor 12. Then, the output value of the gap sensor 12 that changes with the rotation of the turbocharger 1 with an electric motor has a peak value every time the rotational position of the compressor blade 53 faces the sensor unit 13 (FIG. 2B). reference). Then, when shaft shake occurs in the rotating bodies 41, 51, 8, and 6 of the turbocharger 1 with electric motor, the magnitude of the peak value changes as shown in FIGS. The shaft shake amount calculation means 162 calculates the shaft shake amount based on the magnitude of the change in the peak value, and determines whether or not the shaft shake amount exceeds the set value and the shaft shake is in an abnormal state. .
Accordingly, the shaft shake abnormality can be detected using the gap sensor 12 without attaching the rotating slits described in Patent Document 1 to the rotating bodies 41, 51, 8, and 6. Therefore, the performance of the turbocharger 1 with a motor is deteriorated. The shaft shake abnormality of the turbocharger 1 with an electric motor can be detected while avoiding the above.

(Second Embodiment)
A second embodiment of the present invention is shown in FIGS. In addition, the same code | symbol is attached | subjected to the substantially same component as 1st Embodiment.

  In the shaft shake amount detection unit 16 according to the first embodiment, the shaft shake amount is calculated based on the change in the peak value appearing in the output signal of the gap sensor, whereas in the second embodiment, the gap sensor is used. The analog waveform as the 12 output signals is converted into a pulse waveform by the threshold voltage, and the shaft shake amount detector 16 calculates the shaft shake amount based on the change in the width of the pulse appearing in the pulse waveform.

  More specifically, the shaft shake amount detection unit 16 according to the second embodiment includes a pulse conversion unit 163, a pulse width detection unit 164, and a shaft shake amount calculation unit 165 (see FIG. 7). The pulse conversion means 163 converts an analog waveform as an output voltage value of the gap sensor 12 into a pulse waveform using a threshold voltage. That is, the pulse waveform is generated so that the portion of the output voltage value of the gap sensor 12 that is larger than the threshold voltage corresponds to the pulse generating portion (convex portion), and the portion that is smaller than the threshold voltage corresponds to the non-pulse generating portion. Therefore, the pulse waveform has a shape in which a pulse appears every time the rotation position of the compressor blade 53 is opposed to the sensor unit 13 (the position closest to the sensor unit 13).

  After that, the pulse width detection means 164 calculates the width of the generated pulse in the generated pulse waveform, and varies the difference between the maximum pulse width and the minimum pulse width among a plurality of pulse widths within the set period. Calculate as a value. For example, in FIG. 8A, the fluctuation value that is the difference between the minimum pulse width W1 corresponding to the minimum peak value P5 and the maximum pulse width W2 corresponding to the maximum peak value P6 in a predetermined period is W2-W1. In FIG. 8B, the variation value which is the difference between the minimum pulse width W3 corresponding to the minimum peak value P7 and the maximum pulse width W4 corresponding to the maximum peak value P8 in a predetermined period is W4-W3.

  When the shafts of the rotating bodies 41, 51, 8, and 6 occur, the distance between the compressor blade 53 and the sensor unit 13 changes, and therefore the analog output waveform of the gap sensor 12 is a signal whose peak value changes periodically. As a result, the width of the generated pulse also periodically changes (see FIGS. 8A and 8B). When the fluctuation value that is the difference between the maximum peak values P6, P8 and the minimum peak values P5, P7 is large, the fluctuation values (W2-W1), (W4) as the difference between the maximum pulse width and the minimum pulse width. It can be seen from FIGS. 8A and 8B that −W3) also increases.

The shaft shake amount calculation means 165 calculates the shaft shake amount based on the fluctuation values (W2-W1) and (W4-W3) related to the peak value, and the calculated shaft shake amount exceeds the set value. Is determined to be in an abnormal state of shaft shake, and if the set value is not exceeded, it is determined that the abnormal state has not been reached.
When the ECU 15 determines that the shaft shake is abnormal by the shaft shake amount calculation means 165, the ECU 15 controls the motor drive unit 18 to stop the drive of the induction motor 7. The shaft shake amount calculation means 165 corresponds to “shaft shake amount calculation means” and “abnormality determination means” recited in the claims.

Next, the operation of the ECU 15 that detects shaft shake of the turbocharger 1 with an electric motor as described above will be described with reference to the flowchart of FIG.
First, in steps S200 to S240, the rising edge and the falling edge of the pulse signal output from the pulse generation means 163 are detected, and the pulse width is detected.
Specifically, if it is determined that the pulse is a rising edge (S200: Yes), the process proceeds to step S210, and the time T1 at which the rising edge is detected is stored. If it is determined that the pulse is not a rising edge (S200: No), the process of step S200 is repeated.

Next, the process proceeds to step S220, and if it is determined that the pulse is a falling edge (S220: Yes), the process proceeds to step S230, and the time T2 at which the falling edge is detected is stored. If it is determined that the pulse is not a falling edge (S220: No), the process of step S220 is repeated.
In step S240, the difference between the above-described time T2 and time T1 is calculated, and the calculated value (T2-T1) is stored as time T (k) indicating the pulse width.

Next, the maximum pulse width is detected and stored in steps S250, S260, and S270.
Specifically, the previously stored pulse width T (k−1) is equal to or greater than the pulse width T (k−2) of the previous time (S250: Yes), and the current pulse width T (k) is the previous pulse width T. If it is determined that the value is smaller than (k-1) (S260: Yes), the process proceeds to step S270, and the previous pulse width T (k-1) is stored as the maximum pulse width Tmax.

On the other hand, if the previously stored pulse width T (k-1) is smaller than the last pulse width T (k-2) (S250: No), the minimum pulse width is detected and stored in steps S250, S280, and S290. .
Specifically, if it is determined that the current pulse width T (k) is equal to or smaller than the previous pulse width T (k−1) (S280: Yes), the process proceeds to step S290, where the previous pulse width T ( k-1) is stored as the minimum pulse width Tmin.
Note that if the determination in step S260 is No or the determination in step S280 is No, the process returns to step S200.

  Next, in step S300, it is determined whether or not the difference between the maximum pulse width Tmax and the minimum pulse width Tmin exceeds a set value Tth. If it is determined that the set value Tth has been exceeded (S300: Yes), it is considered that the shaft shake is in an abnormal state, and the motor drive unit 18 is controlled to stop driving the induction motor 7 in step S310. If it is determined that the set value Tth has not been exceeded (S300: No), the process returns to step S200.

As described above, according to the second embodiment, the gap sensor 12 detects the distance from the compressor blade 53. Then, a pulse appears in the pulse waveform that changes with the rotation of the turbocharger 1 with electric motor every time the rotational position of the compressor blade 53 is opposed to the sensor unit 13 (see FIG. 8). And when the shaft blur occurs in the rotating bodies 41, 51, 8, and 6 of the turbocharger 1 with electric motor, the magnitude of the pulse width changes as shown in FIGS. 8 (a) and 8 (b). Then, the shaft shake amount calculation means 165 calculates the shaft shake amount based on the magnitude of the change in the pulse width, and determines whether or not the shaft shake amount exceeds the set value and the shaft shake is in an abnormal state. .
Accordingly, the shaft shake abnormality can be detected using the gap sensor 12 without attaching the rotating slits described in Patent Document 1 to the rotating bodies 41, 51, 8, and 6. Therefore, the performance of the turbocharger 1 with a motor is deteriorated. The shaft shake abnormality of the turbocharger 1 with an electric motor can be detected while avoiding the above.

(Third embodiment)
In the first and second embodiments, all of the plurality of compressor blades 53 are detected by the gap sensor 12, and the peak value is equal to the number of compressor blades 53 each time the rotating bodies 41, 51, 8, and 6 make one rotation. Appears. On the other hand, in the third embodiment, the gap sensor 12 detects the peak value of one compressor blade 53 every time the rotating bodies 41, 51, 8, and 6 make one rotation. (See the solid line in FIG. 10).

  More specifically, referring to FIG. 10, the case where there are six compressor blades 53 will be described. In the first and second embodiments, as shown by the dotted lines in FIG. 10, the rotating bodies 41, 51, 8, 6 In the third embodiment, the peak value appears only once every time the rotating bodies 41, 51, 8, and 6 make one revolution.

  In the case of the first and second embodiments, the time required for detection can be shortened, but if there is a physical variation between the compressor blades 53, the detection accuracy is lowered. With respect to this problem, according to the third embodiment, as shown in FIG. 10, since the amount of shaft shake is detected using the same information of the compressor blade 53, the detection accuracy can be improved.

(Other embodiments)
In the first embodiment, a predetermined period is set as the predetermined period in calculating a variation value that is a difference between the maximum peak value and the minimum peak value in a predetermined period. However, as a modification of the first embodiment, The shaft shake amount calculating means 162 may measure the fluctuation cycle of the peak value and set the measured fluctuation cycle as the predetermined period.

  In the second embodiment, when calculating a variation value that is a difference between the maximum pulse width and the minimum pulse width in a predetermined period, a predetermined period is set as the predetermined period. The fluctuation period of the pulse waveform may be measured, and the measured fluctuation period may be set as the predetermined period.

  In each of the above embodiments, when it is determined in steps S100 and S300 that the shaft shake is abnormal, control is performed so that the drive of the induction motor 7 is stopped in steps S110 and S310. When it is determined that the shaft shake is in an abnormal state, the degenerate operation for reducing the shaft shake amount by reducing the assist amount of the induction motor 7 may be performed. Note that when performing the degenerate operation or when stopping the induction motor 7, it is preferable to notify the driver by display or voice or the like that the shaft shake is abnormal.

In each of the above-described embodiments, only the example in which the turbocharger 1 with an electric motor is assisted by the induction motor 7 is disclosed. However, for example, when the target rotation speed is lower than the actual rotation speed, the induction motor 7 is used as a generator. May be.
In each of the above embodiments, an example in which the induction motor 7 is mounted in the housing 2 of the turbocharger 1 with electric motor has been described. However, the shaft 6 of the turbocharger 1 with electric motor is extended to the outside of the housing 2, and You may provide so that the shaft 6 of the turbocharger 1 may be driven with the induction motor 7 mounted outside.
Further, the present invention is not limited to the application to the turbocharger 1 with an electric motor, but can also be applied to the turbocharger 1 with an electric motor that does not include the induction motor 7.
As described above, the present invention is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

The schematic diagram which shows the structure of the turbocharger with an electric motor and shaft shake abnormality detection apparatus by 1st Embodiment of this invention. (A) is a schematic diagram which shows the positional relationship of the compressor shown in FIG. 1, and a sensor part, (b) is a figure which shows the time change of the output voltage of a gap sensor in the state of (a). (A) is a diagram for explaining shaft shake, (b) is a view taken in the direction of arrow b in (a), and (c) is a diagram showing a time change of output voltage of the gap sensor in a state where shaft shake is small in the first embodiment. (D) is a figure which shows the time change of the output voltage of a gap sensor in a state with a large axial blur. FIG. 2 is a block diagram showing details of a shaft shake amount detection unit shown in FIG. 1. The figure explaining the abnormality determination performed by ECU shown in FIG. The flowchart explaining the operation | movement at the time of detecting the shaft shake by ECU shown in FIG. The block diagram which shows the detail of the axial shake amount detection part by 2nd Embodiment of this invention. (A) is a figure which shows the time change of the output voltage of a gap sensor in a state with a small axial fluctuation in 2nd Embodiment, (b) is a figure which shows the time change of the output voltage of a gap sensor in a state with a large axial fluctuation. The flowchart explaining the operation | movement at the time of detecting the shaft shake by ECU which concerns on 2nd Embodiment. The figure which shows the time change of the output voltage of a gap sensor in 3rd Embodiment of this invention.

Explanation of symbols

  1: turbocharger with electric motor, 4: turbine, 5: compressor, 7: induction motor, 10: abnormality detection device, 12: gap sensor, 15: ECU (rotational speed calculation means), 53: compressor blade, 162, 165: Shaft shake amount calculation means (shaft shake amount calculation means and abnormality determination means).

Claims (9)

A turbocharger shaft shake abnormality detecting device for detecting a shaft shake abnormality of a turbocharger that supplies compressed air to the engine using an engine exhaust pressure as a drive source,
A gap sensor for detecting a distance from the compressor blade of the turbocharger;
Shaft amount calculation means for calculating the amount of shaft shake of the turbocharger based on the change in peak value that appears in the output signal of the gap sensor every time the rotation position of the compressor blade is opposed to the gap sensor. When,
An abnormality determining means for determining whether or not the amount of shaft shake exceeds a set value and is in an abnormal state of shaft shake;
A shaft shake abnormality detection device for a turbocharger comprising:   2. The turbo shaker shaft shake abnormality detecting device according to claim 1, wherein the shaft shake amount calculating means calculates the shaft shake amount based on a difference between a maximum value and a minimum value among the plurality of peak values appearing within a predetermined period. .   3. The turbocharger shaft shake abnormality detection device according to claim 2, wherein the shaft shake amount calculation means measures a fluctuation cycle of the peak value and sets the measured fluctuation cycle as the predetermined period. A turbocharger shaft shake abnormality detecting device for detecting a shaft shake abnormality of a turbocharger that supplies compressed air to the engine using an engine exhaust pressure as a drive source,
A gap sensor for detecting a distance from the compressor blade of the turbocharger;
Pulse conversion means for converting an analog waveform as an output signal of the gap sensor that changes with rotation of the turbocharger into a pulse waveform by a threshold voltage;
Shaft amount calculation means for calculating the amount of shaft shake of the turbocharger based on a change in the width of a pulse appearing in the pulse waveform every time the rotation position of the compressor blade is opposed to the gap sensor;
An abnormality determining means for determining whether or not the amount of shaft shake exceeds a set value and is in an abnormal state of shaft shake;
A shaft shake abnormality detection device for a turbocharger comprising:   5. The turbocharger shaft shake abnormality detection according to claim 4, wherein the shaft shake amount calculation means calculates the shaft shake amount based on a difference between a maximum width and a minimum width among a plurality of widths of the pulses appearing within a predetermined period. apparatus.   6. The turbocharger shaft shake abnormality detection device according to claim 5, wherein the shaft shake amount calculation means measures a fluctuation period of the pulse waveform and sets the measured fluctuation period as the predetermined period.   6. The turbocharger shaft shake abnormality detecting device according to claim 2, wherein the shaft shake amount calculating means sets a predetermined period as the predetermined period.   The turbocharger shaft shake abnormality detection device according to any one of claims 1 to 7, wherein the turbocharger is a turbocharger with an electric motor that uses an electric motor as a drive source in addition to the exhaust pressure of the engine. The turbocharger shaft shake abnormality detection device according to any one of claims 1 to 8, further comprising a rotation speed calculation unit that calculates a rotation speed of the turbocharger based on an output signal of the gap sensor.

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