JP6436341B2 - Rotation speed detector - Google Patents

Description

  The present invention relates to a rotational speed detection device. In particular, the present invention relates to a turbocharger rotation speed detection device.

  2. Description of the Related Art Conventionally, a rotational speed detection device that detects a rotational speed of a turbocharger compressor or turbine using a change in a magnetic field is known. In the rotational speed detection device, a detection unit (electromagnetic pickup) including a coil for generating a magnetic field is provided in a casing of a compressor or a turbine. The electromagnetic pickup is provided so that a blade as a detection object passes through a magnetic field. The electromagnetic pickup of the rotational speed detection device generates an electromotive force proportional to the derivative of the magnetic flux. That is, the rotation speed detection device detects an induced electromotive force generated in the electromagnetic pickup due to a change in magnetic flux. For example, as in Patent Document 1.

  In such a rotational speed detection device using an electromagnetic pickup, the rotational speed of the compressor or turbine is calculated on the basis of the time point when the end of the blade is closest to the electromagnetic pickup in consideration of the characteristics of the electromagnetic pickup. At this time, since the distance between the electromagnetic pickup and the end of the blade is kept substantially constant, the magnetic flux of the electromagnetic pickup hardly changes and the induced electromotive force becomes weak. Thus, the rotational speed detection device detects the rotational speed of the compressor or turbine from the interval, assuming that the end of the blade passes through the vicinity of the electromagnetic pickup when the induced electromotive force is 0V. However, the rotation speed detection device has a voltage of 0 V not only when the distance between the electromagnetic pickup and the end of the blade is substantially constant, but also when the polarity changes from a positive voltage to a negative voltage depending on the change of the magnetic flux. It becomes the state of. Therefore, in the rotational speed detection device, when the rotational speed is detected based on the time when the induced electromotive force is 0 V, there is a possibility that the blade position corresponding to the induced electromotive force varies and the accurate rotational speed cannot be detected. there were.

JP2013-2312A

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a rotational speed detection device capable of stably detecting the rotational speed of a blade of a compressor or a turbine using an induced electromotive force.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

That is, according to the present invention, there is provided a turbocharger rotational speed detection device in which a detection unit for detecting a main blade and a splitter blade by a change in induced electromotive force is provided in a casing of a compressor, wherein one main blade or one splitter is provided. The peak time of the induced electromotive force generated when the blade passes in the vicinity of the detection unit and the peak time of the induced electromotive force generated when another main blade or other splitter blade passes in the vicinity of the detection unit The rotation speed of the turbocharger is calculated from the interval between the main blades, and the instantaneous rotation speed of the main blade of the turbocharger is calculated from the interval between the peak times of the induced electromotive force generated by the adjacent main blades. Time point of peak of induced electromotive force The turbocharger instantaneous rotation speed of the turbocharger is calculated from the interval, and if the difference between the main blade instantaneous rotation speed and the splitter blade instantaneous rotation speed is greater than or equal to a predetermined value, self-failure diagnosis is performed if an abnormality has occurred in the turbocharger. Is what you do .

In other words, in the present invention, signals for the main blade instantaneous rotation speed and the splitter blade instantaneous rotation speed are transmitted to the engine control device in order to control the opening and closing of the fuel injection valve, intake valve and exhaust valve of the engine. Is.

That is, in the present invention, the average rotational speed is calculated based on the main blade instantaneous rotational speed or the splitter blade instantaneous rotational speed, and the actual fuel injection amount when fuel is injected based on an arbitrary target injection amount is calculated. In order to do so, a signal regarding the amount of change in the average rotational speed is transmitted to the engine control device .

That is, in the present invention, the speed calculated based on the induced electromotive force having the larger absolute value of the induced electromotive force at the peak of the instantaneous rotating speed of the main blade and the instantaneous rotating speed of the splitter blade is set as the turbocharger. It is assumed that this is the instantaneous rotation speed .

  As effects of the present invention, the following effects can be obtained.

  According to the present invention, since the position of the blade corresponding to the peak point of the induced electromotive force is included in a certain range, the calculation results are unlikely to vary. Thus, the rotational speed of the compressor or turbine blade can be stably detected using the induced electromotive force.

  According to the present invention, since the blade position corresponding to the peak point of the induced electromotive force is included in a certain range, the calculated instantaneous rotational speeds of the two systems are unlikely to vary and an accurate self-diagnosis is performed. Thus, the rotational speed of the compressor or turbine blade can be stably detected using the induced electromotive force.

  According to the present invention, the engine is controlled based on the instantaneous rotational speed with reference to the peak time of the induced electromotive force. As a result, the instantaneous rotational speed stably detected by using the induced electromotive force is fed back to control the fuel injection amount, the opening of the EGR valve, etc. Variations can be reduced and the engine can be controlled to an appropriate state according to the load.

  According to the present invention, since the instantaneous rotational speed is calculated based on the blade with the larger external force applied by the rotation, the abnormality of the blade due to the addition of the external force is detected at an early stage. Thus, the rotational speed of the compressor or turbine blade can be stably detected using the induced electromotive force.

Sectional drawing which shows the structure of the turbocharger which concerns on 1st embodiment of this invention, and a rotational speed detection apparatus. (A) The partial cross section figure which shows the positional relationship of the detection part and braid | blade of the rotational speed detection apparatus which concerns on 1st embodiment of this invention. (A) Schematic diagram showing a state in which the blade of the rotational speed detection device according to the present invention does not pass through the magnetic field of the detection device and a diagram showing a waveform diagram (b) State at the moment when the blade enters the magnetic field of the detection device (C) A schematic diagram showing a state where the blade passes through the magnetic field of the detection device and a diagram showing a waveform diagram (d) Similarly, the moment when the blade leaves the magnetic field of the detection device The figure which shows the schematic and waveform diagram showing the state of this. (A) A schematic diagram and a waveform diagram showing a concept for calculating a pitch passage time between the main blade and the splitter blade in the rotational speed detection device according to the present invention. (B) A pitch between the splitter blade and the main blade. The figure which shows the schematic and waveform diagram showing the concept for calculating passage time. (A) The figure which shows the wave form diagram for calculating the pitch passage time between the main blades in the rotational speed detection apparatus which concerns on one Embodiment of this invention (b) The splitter in the rotational speed detection apparatus which concerns on one Embodiment of this invention The figure which shows the wave form diagram for calculating the pitch passage time between braid | blades. The figure which shows the flowchart showing the control which determines abnormality of the turbocharger in the rotational speed detection apparatus which concerns on one Embodiment of this invention. The figure which shows the block diagram showing the relationship between the rotational speed detection apparatus which concerns on one Embodiment of this invention, and an engine. The figure which shows the graph showing the valve opening time of a fuel injection valve, and the relationship of injection amount. (A) Sectional drawing which shows the structure of the turbocharger which concerns on 2nd embodiment of this invention, and a rotational speed detection apparatus. (B) The positional relationship of the connecting shaft of the turbocharger which concerns on 2nd embodiment of this invention, and a detection apparatus. FIG.

  Below, the turbocharger 1 which concerns on 1st embodiment of this invention using FIG. 1 is demonstrated.

  As shown in FIG. 1, the turbocharger 1 supplies the engine 20 with compressed and compressed intake air using the exhaust pressure of the exhaust discharged from the engine 20 (see FIG. 7) as a drive source. The turbocharger 1 includes a connecting portion 2, a turbine 6, a compressor 9, and the like.

  The connecting part 2 connects the turbine 6 and the compressor 9. The connecting portion 2 includes a center housing 3, a connecting shaft 4, a bearing 5, and the like. The center housing 3 has a turbine 6 connected to one side and a compressor 9 connected to the other side. The connecting shaft 4 connects a turbine wheel 8 described later and a compressor wheel 11 described later. The connecting shaft 4 is rotatably supported by the center housing 3 via a bearing 5.

  The turbine 6 converts the exhaust pressure of the engine 20 into a rotational driving force. The turbine 6 includes a turbine casing 7, a turbine wheel 8, and the like.

  The turbine casing 7 is a member formed in a bottomed cylindrical shape. One side (bottom side) of the turbine casing 7 is connected to the center housing 3. On one side of the turbine casing 7, an exhaust supply path 7 a is formed in which exhaust gas is supplied to the outer peripheral portion. On the other side (the opposite bottom side) of the turbine casing 7, an exhaust outlet 7 b is formed. A connecting shaft 4 is communicated with the bottom of the turbine casing 7. The exhaust supply path 7 a of the turbine casing 7 is formed so as to communicate with the inside of the turbine casing 7.

  The turbine wheel 8 includes a turbine hub 8a that is a base portion of the turbine wheel 8, and a plurality of turbine blades 8b that are arranged on the outer peripheral surface 8c of the turbine hub 8a at equal intervals in the circumferential direction. The turbine wheel 88 has a turbine hub 8a fixed to the connecting shaft 4 and is rotatably supported. The turbine hub 8a has an outer peripheral surface 8c on the side opposite to the connecting shaft 4 that is parallel to the axis of the connecting shaft 4 expanding while curving toward the connecting shaft 4, and is connected to the end of the connecting shaft 4 on the connecting shaft 4 side. A flange 8d is formed in a direction perpendicular to the axis of the four axes.

  In the turbine wheel 8, the outer periphery of the flange 8 d (expanded diameter side) of the turbine hub 8 a faces the exhaust supply path 7 a of the turbine casing 7, and the reduced diameter side end of the turbine hub 8 a faces the discharge port 7 b of the turbine casing 7. It arrange | positions inside the turbine casing 7 so that it may oppose. That is, the turbine wheel 8 is disposed so that the turbine hub 8a has a diameter decreasing from the exhaust supply side toward the exhaust side. With this configuration, the turbine wheel 8 is rotated by the exhaust pressure of the supplied exhaust gas, and the exhaust gas is guided from the outer peripheral surface 8c of the turbine hub 8a in a direction parallel to the rotation axis and discharged from the discharge port 7b. Let

  The compressor 9 compresses and compresses the supply air of the engine 20. The compressor 9 includes a compressor casing 10 and a compressor wheel 11.

  The compressor casing 10 is a member formed in a cylindrical shape. One side of the compressor casing 10 is connected to the center housing 3 to form a bottom portion. A connecting shaft 4 is communicated with a bottom portion constituted by the center housing 3. On one side (bottom side) of the compressor casing 10, there is formed an intake air discharge passage 10a through which the intake air is discharged to the outer periphery. An intake supply port 10 b is formed on the other side (the opposite bottom side) of the compressor casing 10. An inner wall 10c of the compressor casing 10 is formed so as to increase in diameter toward one side and communicated with the intake air discharge passage 10a.

  The compressor wheel 11 includes a compressor hub 11a that forms the base of the compressor wheel 11, a plurality of full blades 11b (all blades) and splitter blades that are alternately arranged in the circumferential direction on the outer peripheral surface 11d of the compressor hub 11a. 11c (short wing).

  The compressor wheel 11 has a compressor hub 11a fixed to the connecting shaft 4 and is rotatably supported. That is, the compressor wheel 11 is configured to be able to transmit the rotational power from the turbine wheel 8 via the connecting shaft 4. The compressor hub 11a expands in diameter while the outer peripheral surface 11d on the side opposite to the connecting shaft 4 parallel to the axis of the connecting shaft 4 is curved toward the connecting shaft 4, and the connecting shaft 4 is connected to the end of the connecting shaft 4 side. A flange 11e is formed in a direction perpendicular to the axial center. The outer edge shapes of the full blade 11b (all blades) and the splitter blade 11c (short blade) are formed along the inner wall 10c of the compressor casing 10 so as to form a minute gap. Further, the end of the splitter blade 11c on the reduced diameter side is disposed closer to the expanded diameter than the end of the full blade 11b on the reduced diameter side. The compressor wheel 11 may not have the splitter blade 11c.

  In the compressor wheel 11, the outer periphery of the flange 11 e (expansion side) of the compressor hub 11 a faces the intake air discharge passage 10 a of the compressor casing 10, and the end portion on the reduced diameter side of the compressor hub 11 a is the intake inlet of the compressor casing 10. It arrange | positions inside the compressor casing 10 so as to oppose 10b. That is, the compressor wheel 11 is arranged such that the compressor hub 11a expands from the intake supply side to the discharge side. At this time, the interval between the inner wall 10c of the compressor casing 10 and the compressor hub 11a is configured to become narrower as it approaches the intake air discharge passage 10a. That is, in the compressor casing 10, an intake compression passage 11f (see FIGS. 2 and 3) is configured by a space surrounded by the inner wall 10c of the compressor casing 10, the full blade 11b, the splitter blade 11c, and the outer peripheral surface 11d. . In the compressor wheel 11, a first blade BL1 and a second blade BL2 are composed of a full blade 11b or a splitter blade 11c.

  As described above, in the turbocharger 1, when the exhaust gas is supplied to the turbine 6, the turbine wheel 8 is rotated by the exhaust pressure. The compressor wheel 11 connected to the turbine wheel 8 is rotated by the rotational driving force of the turbine wheel 8. The compressor wheel 11 takes in intake air from the intake air supply port 10b. The taken-in intake air is discharged to the intake air discharge passage 10a by the compressor wheel 11 through the intake air compression passage 11f. At this time, the intake air is pressurized and compressed in the intake compression passage 11f, and compression heat is generated.

  Next, the rotational speed detection device 12 according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. In the present embodiment, the rotation speed detection device 12 detects the rotation speed of the compressor 9, but is not limited to this, and may be configured to detect the rotation speed of the turbine.

  As shown in FIG. 1, the rotational speed detection device 12 detects the rotational speed of the compressor 9. The rotation speed detection device 12 includes a detection unit 13, an amplifier 14, a controller 15, and the like. The rotation speed detection device 12 detects the rotation speed of the compressor 9 by detecting the full blade 11 b and the splitter blade 11 c of the compressor wheel 11 by the detection unit 13.

  The detection unit 13 detects the full blade 11b and the splitter blade 11c. The detection unit 13 is attached by being inserted into an insertion hole 10 d formed on the intake supply port 10 b side of the compressor casing 10. At this time, the detection unit 13 is arranged so that the tip thereof does not protrude from the inner wall 10 c of the compressor casing 10. The detection unit 13 includes a magnet that generates a magnetic field B (not shown) and a detection coil (not shown) inside a substantially cylindrical casing. The detection unit 13 is configured such that the magnetic field B generated from the magnet penetrates the detection coil. That is, the detection unit 13 is configured such that an induced electromotive force is generated in the detection coil when the magnetic flux of the magnetic field B penetrating the detection coil changes. The detection unit 13 outputs the generated induced electromotive force as a detection signal. Thereby, the rotational speed detection device 12 determines that the full blade 11b or the splitter blade 11c has passed in the vicinity of the detection unit 13.

  The detection unit 13 must be arranged so that the full blade 11b and the splitter blade 11c both pass the magnetic field B in order to detect the full blade 11b and the splitter blade 11c having different shapes. Therefore, as shown in FIG. 2, the detection unit 13 needs to be arranged so that the region A in which the full blade 11 b and the splitter blade 11 c are close to the compressor casing 10 is included in the range of the magnetic field B. There is.

  The amplifier 14 amplifies the signal from the detection unit 13. The amplifier 14 is connected to the detection unit 13 and acquires a signal from the detection unit 13. The amplifier 14 amplifies the signal from the detection unit 13 and transmits the amplified signal to the controller 15.

  The controller 15 calculates the rotational speed of the compressor 9. The controller 15 stores various programs and data for processing the amplified signal from the amplifier 14. Specifically, the rotational speed detection device 12 may have a configuration in which a CPU, a ROM, a RAM, an HDD, and the like are connected by a bus, or may be configured by a one-chip LSI or the like.

  The controller 15 stores a compressor rotation speed map M1 for calculating a target rotation speed Vt of the compressor 9 based on the rotation speed N of the engine 20 and the output torque Tq. The controller 15 is connected to the amplifier 14 and can acquire an amplified signal from the amplifier 14. The controller 15 calculates the rotation speed of the compressor 9 using the amplified signal from the amplifier 14. The controller 15 is connected to an ECU 25 that is a control device of the engine 20, and can transmit an amplified signal from the amplifier 14 subjected to predetermined processing to the ECU 25 (see FIG. 7).

  Next, the detection mode of the first blade BL1, the second blade BL2,... Composed of the full blade 11b or the splitter blade 11c in the detection unit 13 of the rotational speed detection device 12 will be described with reference to FIG. In FIG. 3, a range indicated by a two-dot chain line indicates a magnetic field B (detection range) generated by the magnet of the detection unit 13. The rotational speed detection device 12 detects the induced electromotive force generated in the detection coil by changing the magnetic flux when the full blade 11b or the splitter blade 11c passes the magnetic field B.

  As shown in FIG. 3A, in the detection unit 13, when the first blade BL1 formed of the full blade 11b or the splitter blade 11c does not enter the magnetic field B, the magnetic flux of the magnetic field B does not change. Therefore, no induced electromotive force is generated in the detection coil of the detection unit 13.

  As shown in FIG. 3B, in the detection unit 13, when the first blade BL1 enters from the counter-rotation direction side of the magnetic field B, the magnetic flux of the magnetic field B is changed by the proximity of the first blade BL1 to the detection unit 13. It changes rapidly. Therefore, an induced electromotive force having a positive polarity is generated in the detection coil of the detection unit 13 in accordance with a change in magnetic flux according to Faraday's law of electromagnetic induction. The detection coil of the detection unit 13 generates a maximum induced electromotive force with a positive polarity when the amount of change in the magnetic flux of the magnetic field B per unit time is the largest due to the entry of the first blade BL1. Specifically, the induced electromotive force is the maximum induced electromotive force having a positive polarity immediately after the end of the first blade BL1 enters the magnetic field B and immediately approaches the detection unit 13.

  As shown in FIG. 3C, in the detection unit 13, when the first blade BL1 passes through the magnetic field B, the distance between the detection unit 13 and the first blade BL1 is kept substantially constant. The magnetic flux of B changes relatively slowly. Therefore, a small induced electromotive force is generated in the detection coil of the detection unit 13 as compared with the moment when the first blade BL1 enters the magnetic field B according to the change of the magnetic flux. In the detection coil of the detection unit 13, no induced electromotive force is generated when the amount of change per unit time of the magnetic flux of the magnetic field B when the first blade BL1 passes is zero.

  As shown in FIG. 3D, when a part of the first blade BL1 is removed from the rotation direction side of the magnetic field B in the detection unit 13, the first blade BL1 is separated from the detection unit 13 so that the magnetic field B is separated. The magnetic flux changes rapidly. Therefore, a negative polarity induced electromotive force is generated in the detection coil of the detection unit 13 in accordance with the change of the magnetic flux according to Faraday's law of electromagnetic induction. The detection coil of the detection unit 13 generates a maximum induced electromotive force with a negative polarity when the amount of change per unit time of the magnetic flux of the magnetic field B is the largest due to the separation of the first blade BL1. When the first blade BL1 comes off from the rotation direction side of the magnetic field B, the magnetic flux of the magnetic field B does not change because the first blade BL1 does not affect the magnetic field B. Therefore, no induced electromotive force is generated in the detection coil of the detection unit 13.

  In this way, the rotational speed detection device 12 detects the maximum induced electromotive force with a positive polarity at time T11 when the first blade BL1 enters from the counter-rotation direction side of the magnetic field B, and the first blade BL1 By escaping from the rotation direction side of the magnetic field B, the maximum induced electromotive force with a negative polarity is detected at time T12. Furthermore, the rotational speed detection device 12 detects the maximum induced electromotive force with a positive polarity at time T21 when the second blade BL2 enters from the counter-rotation direction side of the magnetic field B, and the second blade BL2 rotates the magnetic field B. By escaping from the direction side, the maximum induced electromotive force with a negative polarity is detected at time T22 (see FIG. 4A). Similarly, the rotational speed detection device 12 detects the induced electromotive force for each of the third blade BL3, the fourth blade BL4,... Of the compressor wheel 11 constituted by the full blade 11b or the splitter blade 11c.

  Next, calculation of the rotational speed by the rotational speed detection device 12 in the operation stage of the compressor 9 will be described with reference to FIG. It is assumed that the compressor wheel 11 is formed so that the blade thickness and the blade pitch of each blade are within a predetermined range in the operation stage, and the dimensions are set in the rotational speed detection device 12. Further, the speed calculation of the compressor wheel 11 is performed for all of the first blade BL1 to the nth blade BL (n) formed on the compressor wheel 11, but since it is the same mode, the first blade made of the main blade is used. The calculation of the rotational speeds of the blade BL1, the third blade BL3, the second blade BL2 and the fourth blade BL4 composed of splitter blades will be described.

  As shown in FIG. 4A, the rotational speed detection device 12 includes a time T11 at which the induced electromotive force becomes maximum in the positive polarity when the first blade BL1, which is the main blade, is close to the detection unit 13, and the splitter blade. A pitch passage time ΔTp12, which is an interval from the time T21 when the induced electromotive force becomes maximum in the positive polarity when a certain second blade BL2 approaches the detection unit 13, is calculated. Then, the rotational speed detection device 12 calculates the first instantaneous rotational speed Vp12 from the preset pitch P12 between the first blade BL1 and the second blade BL2.

  Similarly, as shown in FIG. 4 (b), the rotational speed detection device 12 has the maximum induced electromotive force in the positive polarity because the time T21 and the third blade BL3 as the main blade are close to the detection unit 13. A pitch passage time ΔTp23, which is an interval with the time T31, is calculated. Then, the rotation speed detection device 12 calculates the second instantaneous rotation speed Vp23 from the preset pitch P23 between the second blade BL2 and the third blade BL3. In this way, the rotational speed detection device 12 calculates the second instantaneous rotational speed Vp23... Nth instantaneous rotational speed Vp (n) 1 in order from the first instantaneous rotational speed Vp12.

  The rotation speed detection device 12 calculates the pitch passage time ΔTp12 · ΔTp23 ·· with reference to the point in time when the magnetic flux of the magnetic field B changes abruptly when the first blade BL1 · second blade BL2 ·· approaches the detection unit 13. To do. In other words, the rotational speed detection device 12 passes the pitch based on the induced electromotive force in a state where the position corresponding to the peak time point of the induced electromotive force of the first blade BL1, the second blade BL2,. Time ΔTp12 · ΔTp23 ·· is calculated. Thereby, the rotational speed detection apparatus 12 can detect stably the rotational speed of the blade of the compressor 9 or the turbine 6 using the induced electromotive force. In this embodiment, the pitch passage time ΔTp12 · ΔTp23 ·· is calculated on the basis of the time point when the induced electromotive force becomes maximum in the positive polarity, but is not limited to this, and is maximum in the negative polarity. The time point may be used as a reference.

  Next, the abnormality determination by the self-failure diagnosis of the compressor wheel 11 using the detection signal of the rotation speed detection device 12 in the operation stage of the compressor 9 will be described with reference to FIG. The abnormality determination of the compressor wheel 11 is performed for all of the first blade BL1 to the nth blade BL (n) formed on the compressor wheel 11.

  As shown in FIG. 5 (a), the rotational speed detection device 12 causes the induced electromotive force to be generated when the first blade BL1 that is the main blade and the third blade BL3 that is the adjacent main blade are close to the detection unit 13. A pitch passage time ΔTp13 that is an interval between the time T11 and the time T31 that are maximum in the positive polarity is calculated. Then, the rotational speed detection device 12 calculates the first main blade instantaneous rotational speed Vp13 from the preset pitch P13 between the first blade BL1 and the third blade BL3. Similarly, the rotational speed detection device 12 calculates the second main blade instantaneous rotational speed Vp35... Based on the time when the induced electromotive force is maximum in the positive polarity in the adjacent main blades.

  Next, as illustrated in FIG. 5B, the rotational speed detection device 12 is guided by the proximity of the second blade BL <b> 2 that is a splitter blade and the fourth blade BL <b> 4 that is an adjacent splitter blade to the detection unit 13. A pitch passage time ΔTp24 that is an interval between the time T21 and the time T41 at which the electromotive force becomes maximum in the positive polarity is calculated. Then, the rotation speed detection device 12 calculates the first splitter blade instantaneous rotation speed Vp24 from the preset pitch P24 between the second blade BL2 and the fourth blade BL4. Similarly, the rotational speed detection device 12 calculates the second splitter blade instantaneous rotational speed Vp46... Based on the time when the induced electromotive force is maximum in the positive polarity in the adjacent splitter blade.

  Here, as shown in FIG. 5A, the rotational speed detection device 12 is configured such that the first main blade instantaneous rotational speed Vp13 and the induced electromotive force peak value when the induced electromotive force peak value is aV. The first main blade instantaneous rotation speed Vp13 calculated based on the induced electromotive force of aV having a large induced electromotive force at the peak of the induced electromotive force among the first splitter blade instantaneous rotation speed Vp24 having a bV of turbocharger. 1 instantaneous rotational speed is assumed. The first blade BL1 and the third blade BL3 that are the main blades for which the first main blade instantaneous rotation speed Vp13 is calculated are closer to the detection unit 13 than the second blade BL2 and the fourth blade BL4 that are splitter blades. ing. That is, since the end portions of the first blade BL1 and the third blade BL3 are outside the end portions of the second blade BL2 and the fourth blade BL4 that are splitter blades, the peripheral speed is high. Accordingly, the rotational speed detection device 12 uses the first main blade instantaneous rotational speed Vp13 calculated based on the first blade BL1 and the third blade BL3, which have a larger external force applied by the rotation, as the instantaneous rotational speed of the turbocharger 1. Therefore, the abnormality of the turbocharger 1 can be detected early.

  The rotational speed detection device 12 is configured to use the first main blade instantaneous rotational speed Vp13, the second main blade instantaneous rotational speed Vp35,..., The main blade average rotational speed Vm that is the average rotational speed of the compressor 9 (turbocharger 1), or the first main blade instantaneous rotational speed Vp35. The splitter blade average rotational speed Vs, which is the average rotational speed of the compressor 9 (turbocharger 1), is obtained from the one splitter blade instantaneous rotational speed Vp24, the second splitter blade instantaneous rotational speed Vp46. Further, the rotational speed detection device 12 determines the abnormality of the compressor 9 from the difference (or ratio) between the calculated first main blade instantaneous rotational speed Vp13 and the first splitter blade instantaneous rotational speed Vp24.

  Next, the abnormality determination of the compressor wheel 11 using the detection signal at the operation stage in the rotational speed detection device 12 according to the present invention will be specifically described with reference to FIGS. In this embodiment, the rotational speed detection device 12 includes the first blade BL1, the third blade BL3, the fifth blade BL5, which are main blades, the second blade BL2, the fourth blade BL4, and the sixth blade, which are splitter blades. BL6 will be described. The rotational speed detection device 12 includes a time T11, a time T31, a time T51, and a splitter blade in which the first blade BL1, the third blade BL3, and the fifth blade BL5 which are main blades detect the maximum induced electromotive force with a positive polarity. It is assumed that time T21, time T41, and time T61 at which the second blade BL2, the fourth blade BL4, and the sixth blade BL6 are detected the maximum induced electromotive force with a positive polarity are detected.

  As shown in FIG. 6, in step S110, the rotational speed detection device 12 calculates the pitch passage time ΔTp13 from the detected time T11 and time T31, and calculates the pitch passage time ΔTp35 from the detected time T31 and time T51. To step S120.

  As shown in FIG. 6, in step S120, the rotational speed detection device 12 calculates the pitch passage time ΔTp24 from the detected time T21 and time T41, and calculates the pitch passage time ΔTp46 from the detected time T41 and time T61. To step S130.

  In step S130, the rotational speed detection device 12 calculates and calculates the first main blade instantaneous rotational speed Vp13 from the calculated pitch passage time ΔTp13 and the set pitch P13 between the first blade BL1 and the third blade BL3. The second main blade instantaneous rotational speed Vp35 is calculated from the pitch passage time ΔTp35 and the set pitch P35 between the third blade BL3 and the fifth blade BL5, and the step proceeds to step S140.

  In step S140, the rotational speed detection device 12 calculates and calculates the first splitter blade instantaneous rotational speed Vp24 from the calculated pitch passage time ΔTp24 and the set pitch P24 between the second blade BL2 and the fourth blade BL4. The second splitter blade instantaneous rotational speed Vp46 is calculated from the pitch passing time ΔTp46 and the set pitch P46 between the fourth blade BL4 and the sixth blade BL6, and the process proceeds to step S150.

  In step S150, the rotational speed detection device 12 calculates the average rotational speed of the compressor 9 (turbocharger 1) based on the main blade from the calculated first main blade instantaneous rotational speed Vp13 and second main blade instantaneous rotational speed Vp35. A certain main blade average rotation speed Vm is calculated, or the average rotation of the compressor 9 (turbocharger 1) based on the splitter blade is calculated from the calculated first splitter blade instantaneous rotation speed Vp24 and second splitter blade instantaneous rotation speed Vp46. The splitter blade average rotational speed Vs, which is the speed, is calculated, and the process proceeds to step S160.

  In step S160, the rotational speed detection device 12 transmits the first main blade instantaneous rotational speed Vp13 to the ECU 25 or the like as the instantaneous rotational speed of the turbocharger 1, and the main blade average rotational speed Vs or the splitter blade average rotational speed Vs is transmitted to the turbocharger 1. The average rotation speed is transmitted to the ECU 25 or the like, and the step proceeds to step 160.

  In step S170, the rotational speed detection device 12 determines whether or not the absolute value of the difference between the calculated first main blade instantaneous rotational speed Vp13 and the first splitter blade instantaneous rotational speed Vp24 is less than the first reference value δ1. Here, the first reference value δ1 refers to a dimension that is determined to be aged deterioration of the compressor wheel 11. As a result, when it is determined that the absolute value of the difference between the calculated first main blade instantaneous rotational speed Vp13 and the first splitter blade instantaneous rotational speed Vp24 is less than the first reference value δ1, the rotational speed detecting device 12 performs the steps. The process proceeds to step S110. On the other hand, when it is determined that the absolute value of the difference between the calculated first main blade instantaneous rotational speed Vp13 and the first splitter blade instantaneous rotational speed Vp24 is not less than the first reference value δ1, the rotational speed detecting device 12 performs the step in step S280. To migrate.

  In step S280, the rotational speed detection device 12 determines that an abnormality has occurred in the turbocharger 1 (compressor 9), transmits the abnormality to the ECU 25, etc., and proceeds to step 110.

  Thus, the rotational speed detection device 12 detects the first main blade instantaneous rotational speed Vp13, the second main blade instantaneous rotational speed Vp35, the first splitter blade instantaneous rotational speed Vp24, and the second splitter blade instantaneous rotational speed Vp46. Is calculated based on the time point when the maximum induced electromotive force is generated. That is, the rotational speed detection device 12 is less likely to vary in the calculation result because the position of each blade corresponding to the peak time of the induced electromotive force is included in a certain range. Furthermore, since the rotational speed detection device 12 includes the blade position corresponding to the peak point of the induced electromotive force within a certain range, the calculated instantaneous rotational speeds of the two systems are less likely to vary and an accurate self-diagnosis is performed. Is called. Thereby, the rotational speed detection apparatus 12 can detect the rotational speed of the compressor 9 or the turbine 6 stably using the induced electromotive force. In addition, the rotational speed detection device 12 can determine the state of the compressor 9 (turbine 6) from the comparison between the first main blade instantaneous rotational speed Vp13 and the first splitter blade instantaneous rotational speed Vp24.

  Further, by calculating the first main blade instantaneous rotational speed Vp13 and the first splitter blade instantaneous rotational speed Vp24, which are detection signals at the operation stage in the rotational speed detection device 12 according to the present invention, the speed fluctuation of the compressor 9 is further increased. Accurately grasped. Thus, in the control of the engine 20 having the configuration shown in FIG. 7, the first main blade instantaneous rotation speed Vp13 and the first splitter blade instantaneous rotation speed Vp24 are fed back and the fuel injection valve 21, the intake valve 22 and the exhaust gas of the engine 20 are fed back. By controlling the opening degree of the valve 23 and the EGR valve 24, it is possible to accurately cope with a change in the load of the engine 20 to reduce the variation in exhaust, and to control the engine 20 to an appropriate state according to the load. it can.

  Further, the compressor 9 having a mass sufficiently smaller than the mass of the engine 20 has a main blade average rotation speed Vs or a splitter blade average rotation speed Vs which is an average rotation speed of the compressor 9 when the fuel injection amount fluctuates. The speed fluctuates with higher sensitivity than the rotational speed N. Therefore, based on the main blade average rotation speed Vs or the splitter blade average rotation speed Vs, injection amount correction for correcting the fuel injection amount from the rotation speed N of the engine 20 that has fluctuated due to the minute injection of fuel can be performed.

  Specifically, as shown in FIGS. 7 and 8, the ECU 25 detects the main blade average rotational speed acquired from the rotational speed detection device 12 in addition to the rotational speed N of the engine 20 detected by the engine rotational speed detection sensor 16. The actual fuel injection amount Q1 at the target valve opening time TQt is calculated from Vs or the splitter blade average rotational speed Vs. Then, the ECU 25 corrects the valve opening time TQ of the fuel injection valve 21 to the valve opening time TQr so that the actual fuel injection amount Q1 (two-dot chain line in FIG. 8) becomes the target injection amount Qt (solid line in FIG. 8). . Thereby, even in the large engine 20 having a large mass, the injection amount correction by the micro injection can be more accurately performed by using the main blade average rotation speed Vs or the splitter blade average rotation speed Vs of the compressor 9.

  Below, the rotational speed detection apparatus 12 in 2nd embodiment of the rotational speed detection apparatus 12 which concerns on this invention is demonstrated using FIG. In the following embodiments, the same points as those of the above-described embodiments will not be specifically described, and different portions will be mainly described.

  As shown in FIG. 9A, the turbocharger 26 in the second embodiment supplies the engine 20 with the compressed and compressed intake air by using the exhaust pressure of the exhaust discharged from the engine 20 (see FIG. 7) as a drive source. To do. The turbocharger 26 includes a connecting portion 2, a turbine 6, a compressor 9, and the like.

  The connecting part 2 connects the turbine 6 and the compressor 9. The connecting portion 2 includes a center housing 3, a connecting shaft 27, a bearing 5, and the like. The center housing 3 has a turbine 6 connected to one side and a compressor 9 connected to the other side. The connecting shaft 27 connects a turbine wheel 8 described later and a compressor wheel 11 described later. The connecting shaft 27 is rotatably supported by the center housing 3 via the bearing 5.

  In the turbine wheel 8, a turbine hub 8 a is fixed to the connecting shaft 27. The turbine hub 8a has an outer peripheral surface 8c on the side opposite to the connecting shaft 27 that is parallel to the axis of the connecting shaft 27 and is expanded in diameter while being curved toward the connecting shaft 27 side. A flange 8d is formed in a direction perpendicular to the axial center. The compressor wheel 11 has a compressor hub 11 a fixed to the connecting shaft 27. That is, the compressor wheel 11 is configured to be able to transmit the rotational power from the turbine wheel 8 via the connecting shaft 27.

  The connecting shaft 27 connects the turbine wheel 8 and the compressor wheel 11. One side of the connecting shaft 27 is connected to the rotation center of the turbine wheel 8. The other side of the connecting shaft 27 is connected to the rotation center of the compressor wheel 11. The connecting shaft 27 is rotatably supported by the center housing 3 via the bearing 5. As shown in FIGS. 9A and 9B, the middle portion of the connecting shaft 27 is formed with a regular polygonal chamfered portion 28 in an axial sectional view. The chamfered portion 28 is configured such that the surface portion 28 a or the side portion 28 b matches the number of main blades and / or splitter blades of the turbine wheel 8 or the compressor wheel 11. In the present embodiment, when the number of the main blades 11 b of the compressor wheel 11 is ten, the chamfered portion 28 is formed in a regular decagon in the axial sectional view of the connecting shaft 27.

  The detection unit 13 of the rotational speed detection device 12 detects the surface portion 28 a and the side portion 28 b of the chamfered portion 28. The detection unit 13 is inserted and attached to an insertion hole 3 a formed in the vicinity of the connecting shaft 27 of the center housing 3. The detection unit 13 is disposed in a state of facing the chamfered portion 28 so that the tip thereof does not contact the chamfered portion 28. The distance between the detector 13 and the chamfer 28 varies by the difference between the distance D1 from the rotation center C of the connecting shaft 27 to the surface portion 28a and the distance D2 from the rotation center C to the side portion 28b. Accordingly, the magnetic flux B of the magnetic field B of the detection unit 13 changes suddenly as the connecting shaft 27 rotates and passes through the surface portions 28a and the side portions 28b alternately. As a result, a positive polarity induced electromotive force is generated in the detection coil of the detection unit 13 in accordance with the change of the magnetic flux according to Faraday's law of electromagnetic induction.

  Since the position of the surface portion 28a or the side portion 28b of the chamfered portion 28 corresponding to the peak point of the induced electromotive force is included in a certain range, the rotational speed detection device 12 is less likely to vary in calculation results. Thus, the rotational speed of the compressor or turbine blade can be stably detected using the induced electromotive force.

DESCRIPTION OF SYMBOLS 1 Turbocharger 6 Turbine 9 Compressor 10 Compressor casing 12 Rotational speed detection apparatus 13 Detection part BL1 1st blade BL2 2nd blade Vp12 1st instantaneous rotational speed Vp23 2nd instantaneous rotational speed

Claims (4)

A turbocharger rotation speed detection device provided with a detection unit for detecting a main blade and a splitter blade by a change in induced electromotive force in a casing of a compressor,
Occurs when the peak of the induced electromotive force generated when one main blade or one splitter blade passes in the vicinity of the detection unit and when another main blade or other splitter blade passes in the vicinity of the detection unit Calculate the rotation speed of the turbocharger from the interval from the peak time of the induced electromotive force ,
While calculating the main blade instantaneous rotation speed of the turbocharger from the interval of the peak time of the induced electromotive force generated by each adjacent main blade,
Calculate the instantaneous rotation speed of the splitter blade of the turbocharger from the interval between the peak times of the induced electromotive force generated by the adjacent splitter blades,
A rotational speed detection device that performs self-failure diagnosis when an abnormality has occurred in the turbocharger when the difference between the instantaneous rotational speed of the main blade and the instantaneous rotational speed of the splitter blade is equal to or greater than a predetermined value . The rotation according to claim 1, wherein a signal about the instantaneous rotation speed of the main blade and the instantaneous rotation speed of the splitter blade is transmitted to an engine control device in order to control opening and closing of the fuel injection valve, intake valve and exhaust valve of the engine. Speed detection device. Calculate the average rotation speed based on the main blade instantaneous rotation speed or the splitter blade instantaneous rotation speed,
The rotational speed detection according to claim 2, wherein a signal about an amount of change in average rotational speed is transmitted to the engine control device in order to calculate an actual fuel injection quantity when fuel is injected based on an arbitrary target injection quantity. apparatus. The speed calculated based on the induced electromotive force having the larger absolute value of the induced electromotive force at the peak of the main blade instantaneous rotating speed and the splitter blade instantaneous rotating speed is the instantaneous rotating speed of the turbocharger. speed detecting apparatus according to any one of claims 1 to 3, regarded.

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