JP6234199B2 - Turbocharger rotation state detection device - Google Patents

Description

  The present invention relates to a turbocharger rotation state detection device, and in particular, the rotation speed of a turbocharger rotation state detection device can be easily measured by allowing a compressor blade to pass through rotation of a compressor wheel and capturing pressure fluctuations in a housing. The present invention relates to a turbocharger rotation state detection apparatus.

  Conventionally, as a method for detecting the rotation speed of a turbocharger, for example, a method of detecting a passing frequency of a compressor blade by installing a distance sensor in a compressor housing provided on the outer peripheral side of a compressor wheel having a plurality of compressor blades is known. Yes. In this case, if the blade thickness of the compressor blade is too thin, the sensor cannot detect the compressor blade, or if the number of blades is large and the rotation speed is high, it exceeds the frequency response capability of the sensor and is not applicable mainly to small-diameter turbochargers. There are many cases.

  As another rotation speed detection method, there is a method in which a coil is arranged outside the compressor housing, a current is passed therethrough to generate a magnetic field, and a nut on the rotation shaft of the compressor blade is magnetized. According to this method, an induction pulse is generated in the coil as the nut magnetic field crosses the magnetic field generated by the coil current. Since this pulse is synchronized with the rotation frequency, the rotation frequency can be detected. However, since this method has a weak magnetic field, it is often not applicable to a large-diameter impeller.

  As another rotation speed detection method, there is a method of detecting a passing frequency of a step using a gap sensor that detects a distance provided on the outer peripheral side of the rotation shaft by providing a step. In this method, the rotating shaft itself needs to be processed. In addition, an additional step of readjustment of the rotation balance is required to ensure the rotation balance accurately. In particular, since a small-diameter turbocharger is often used at a high rotational speed, it is necessary to precisely adjust the rotational balance, and the processing cost is a problem. In addition, with a small-diameter turbocharger, there is a difficulty that such step machining is difficult from the viewpoint of strength.

  In Patent Document 1, a flow velocity sensor is provided in a supply air outlet passage (diffuser) through which the compressor blades pump supercharged air, and the flow velocity sensor detects the unit of change from the periodic flow velocity change of the supercharged air corresponding to each blade. The number of blades that have supplied supercharged air per hour is obtained, and the rotational speed of the turbo rotor is obtained from the number of blades and the total number of compressor blades.

  Further, in Patent Document 2, pressure detection means for outputting a signal in response to pressure fluctuations caused by passage of turbine blades of a rotor of a turbo device is provided in the casing, and the frequency of the signal is analyzed by frequency analysis of the signal from the pressure detection means. The number of revolutions of the turbo device is detected by measuring means for measuring the fundamental frequency from the components.

JP 2003-97281 A JP 2003-240788 A

However, in Patent Document 1, the flow rate sensor obtains the number of blades that have supplied supercharged air per unit time from the periodic flow rate change of the supercharged air corresponding to each blade, and the number of blades and the compressor blades. Since the number of rotations is obtained through various calculations of obtaining the number of rotations from the total number of blades, the complexity is undeniable.
On the other hand, in Patent Document 2, even if pressure detection means that outputs a signal in response to pressure fluctuations caused by passage of turbine blades is used, frequency analysis is performed by FFT (Fast Fourier Transform), and it is difficult to suppress product cost. It is.
The present invention has been proposed in order to improve the above-mentioned problems. The measurement principle is newly reviewed, and attention is paid to the sound signal or pressure fluctuation signal of the turbocharger so that measurement can be performed directly from each signal. In order to obtain the best S / N, the acquisition position of the sound signal or pressure fluctuation signal is determined and the sound signal or pressure fluctuation signal is captured so that the rotation speed or rotation state of the turbocharger can be easily detected. An object of the present invention is to provide a turbocharger rotation state detection device.

In order to solve the above problems, in the present invention according to claim 1, a turbine wheel and a compressor wheel connected with a rotor shaft as a rotation shaft, a turbine housing for accommodating the turbine wheel, and a compressor housing for accommodating the compressor wheel are provided. In the turbocharger rotation state detecting device, a takeout hole formed through the shroud portion of the compressor housing located downstream of the compressor blade of the compressor wheel from the outside of the compressor housing toward the inside of the compressor housing, and the takeout A pressure fluctuation detection unit that detects pressure fluctuation in the compressor housing, which is taken out in the hole, and a rotation state detection part that detects the rotation speed or rotation fluctuation of the compressor wheel based on the detection signal of the pressure fluctuation detection unit; Wherein the opening of the extraction hole, characterized in that the formed in accordance with the inclination of the rotation axis direction of the blade height the upper edge of the compressor blades.

  As a result, the pressure is increased by the rotation of the compressor wheel in the compressor housing, and the take-out hole formed in the shroud portion of the compressor housing located downstream of the compressor blade of the compressor wheel from the outside of the compressor housing toward the inside of the compressor housing. Therefore, a part of the supercharged air can be taken out as a pulsation accompanied by a high pressure fluctuation. The pressure fluctuation can be detected by the pressure fluctuation detector, and the rotational state or rotational state of the compressor wheel can be detected by the rotational state detector based on the detection signal of the pressure fluctuation detector.

  The present invention according to claim 2 is characterized in that the pressure fluctuation detecting portion is disposed in an expansion chamber formed in the compressor housing and communicating with the take-out hole.

  As a result, when the compressor blades pass, the supercharged air passes through the take-out hole and passes through the pressure fluctuation detection unit. Therefore, the pressure fluctuation detection unit can largely extract the pressure fluctuation.

  The present invention according to claim 3 is characterized in that the pressure fluctuation detecting section comprises a semiconductor pressure sensor.

  Thereby, the pulsation of the supercharged air taken out from the take-out hole can be reliably captured by the semiconductor pressure sensor.

  According to a fourth aspect of the present invention, the pressure fluctuation detection unit is composed of a sound pressure sensor.

  Thereby, a part of the supercharged air taken out from the take-out hole can be taken out as a pulsation accompanied by a high pressure fluctuation. In this case, a pulsation accompanied by a high pressure fluctuation can be extracted as a sound pressure fluctuation.

Further , the present invention is characterized in that the opening of the extraction hole is formed in accordance with the inclination in the rotation axis direction of the blade height upper end edge of the compressor blade.

The compressor blades are rotated in the circumferential direction of the compressor housing in the compressor housing by the rotation of the compressor wheel.
The compressor blade is formed in a curved shape that expands from the introduction side to the discharge side in the rotation axis direction, and is provided so that the take-out hole is aligned with the inclination in the rotation axis direction of the upper edge of the blade height of the compressor blade. Can do. For this reason, the upper edge of the blade height of the compressor blade can surely pass through the take-out hole by the rotation of the compressor wheel, and the take-out hole can be shielded and opened instantly. Therefore, the high-pressure supercharged air in the compressor housing can be taken out as pressure fluctuation through the take-out hole.

Further, in the present invention according to claim 5 , the circumferential width of the take-out hole is substantially the same as the blade thickness of the compressor blade, and the pressure fluctuation detecting unit has a space on the front side in the rotational direction of the compressor blade that passes through the take-out hole. The pressure difference in the space on the rear side in the rotational direction is detected.

  As a result, there is a pressure difference between the space on the front side in the rotational direction of the compressor blade and the space on the rear side in the rotational direction, and the pressure difference between the front and rear surfaces of the compressor blade is measured by the number of compressor blades in one revolution of the turbo. As a result, the number of rotations can be measured.

Further, the present invention according to claim 6 is characterized in that the rotational state detection unit includes a swell detection unit that detects a swell that changes every predetermined period from a pressure change of each compressor blade.

  As a result, stall in the compressor blade can be detected from pressure fluctuations on the front and rear surfaces of the compressor blade, leading to detection of presurge and surging.

  According to the present invention, a rotating compressor blade passes through a shroud portion of the compressor housing located on the downstream side of the compressor blade of the compressor wheel by the take-out hole drilled from the outside of the compressor housing into the compressor housing. Pressure fluctuations in the compressor housing can be taken out as pressure fluctuations, and based on the pressure fluctuations, the number of rotations or rotation fluctuations, presurge and surging can be detected.

The schematic block diagram which shows an example of the turbocharger provided with the rotation state detection apparatus which concerns on this invention is shown. FIG. 2 is an enlarged view of main parts of a compressor housing and compressor blades in the turbocharger shown in FIG. 1. It is a schematic diagram which shows 1st Embodiment which has arrange | positioned the pressure fluctuation detection part in the rotation state detection apparatus which concerns on this invention in the compressor housing. It is a graph which shows the pressure fluctuation in the compressor housing detected by the pressure fluctuation detection part shown in FIG. It is a schematic diagram which shows 2nd Embodiment which has arrange | positioned the pressure fluctuation detection part in the compressor housing in the rotation state detection apparatus which concerns on this invention. It is a graph which shows the pressure fluctuation in the compressor housing detected by the pressure fluctuation detection part shown in FIG. It is a schematic diagram which shows an example of the attachment hole formed according to the formation direction of the blade height upper end edge of a compressor blade. It is a schematic diagram which shows another example of the attachment hole formed according to the formation direction of the blade height upper end edge of a compressor blade. It is a graph which shows an example of the pressure fluctuation taken out by a pressure fluctuation detection part.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the dimensions, materials, shapes, relative positions, and the like of the components described in the following embodiments are not intended to limit the scope of the present invention unless otherwise specified, and are merely descriptions. It is just an example.

FIG. 1 shows an example of a turbocharger 1 provided with a rotational state detection device according to the present invention.
The turbocharger 1 includes a turbine wheel 3, a compressor wheel 4, a turbine housing 5 that houses the turbine wheel 3, and a compressor housing 6 that houses the compressor wheel 4. The compressor housing 6 has a scroll 8 that communicates with the air delivery passage 7 (hereinafter referred to as a diffuser 7).

  The turbocharger 1 is a rotating machine that generates supercharged air by exhaust energy, and the compressor wheel 4 accommodated in the compressor housing 6 includes compressor blades 4a. The compressor blade 4a gives kinetic energy to the air flowing into the compressor housing 6 from the left in the figure by the rotation of the compressor wheel 4, and the diffuser 7 converts the kinetic energy given to the air into pressure (deceleration). In the scroll 8, the air flow is guided in the circumferential direction and collected.

The turbocharger 1 as described above is equipped with the rotation state detection device 10.
The rotation state detection device 10 has an extraction hole 11 formed through the shroud portion 6 s of the compressor housing 6 located on the downstream side of the compressor blade 4 a of the compressor wheel 4 from the outside of the compressor housing 6 toward the inside of the compressor housing 6. Via the pressure fluctuation detection unit 12 for detecting the pressure fluctuation in the compressor housing 6 and the rotation state detection for detecting the rotational speed or rotation fluctuation of the compressor wheel 4 and the stall in the compressor blades based on the detection signal of the pressure fluctuation detection unit 12. Part 13 (see FIG. 2).

As described above, the take-out hole 11 compresses the air introduced into the compressor housing 6 by the rotation of the compressor wheel 4 to form supercharged air, and a part of the supercharged air reaches the diffuser 7 in the vicinity. That is, it is formed so that it can be taken out at a position where the pressure is increased by the rotation of the compressor wheel 4.
Further, in this embodiment, when the detection signal is sufficiently strong, the take-out hole 11 is shielded by the compressor blade 4a at a position where the compressor blade 4a in the compressor wheel 4 passes by rotation. It is also possible to increase the accuracy and resolution by forming the same size.

Next, the rotation state detection device 10 will be described more specifically as the first embodiment.
(First embodiment)
The pressure fluctuation detection unit 12 includes a pressure sensor 12 (semiconductor pressure sensor) that is directly attached to the take-out hole 11 and detects pressure fluctuation of a part of the supercharged air taken out through the take-out hole 11.
The rotation state detection unit 13 includes a detection signal amplifier 14, a waveform shaping circuit 16, and a counter 17. In addition to the counter 17, an F / V converter is also possible.

For example, as shown in FIG. 3, the pressure sensor 12 is mounted so as to be closed in an extraction hole 11 formed toward the inside of the compressor housing 6. In this case, for example, the pressure sensor 12 can be, for example, a diaphragm type semiconductor pressure sensor.
In this case, when the compressor wheel 4 rotates, the compressor blade 4 a passes through the opening of the take-out hole 11. The pressure fluctuation at this time is captured by the pressure sensor 12 (see FIG. 4). FIG. 4 schematically shows pressure fluctuations captured by the pressure sensor 12. Here, before the compressor blade 4a passes through the opening of the extraction hole 11, the pressure captured by the pressure sensor 12 is at the H level, and after passing through the opening of the extraction hole 11, the pressure is at the L level as shown in the figure. It becomes.

  In the waveform shaping circuit 16, the signal from the detection signal amplifier 14 is shaped into a pulse signal, and the shaped pulse signal is counted by the counter 17, so that the compressor blade 4 a in the compressor wheel 4 passes through the rotation. The rotation speed of the turbocharger 1 is measured.

(Second Embodiment)
Next, the rotation state detection apparatus 10 according to the second embodiment will be described.
That is, in the second embodiment, based on the siren principle, the pressure fluctuation detection unit 12 uses a sound pressure sensor (microphone) to capture the pressure fluctuation in the compressor housing 6 as the sound pressure fluctuation caused by the compressor blades 4a. (See FIG. 5).
The microphone 12 is formed in the compressor housing 6 and disposed in an expansion chamber 18 that communicates with the take-out hole 11. The expansion chamber 18 may be a completely closed space.
In this case, the microphone 12 is arranged in a non-contact state in the extraction hole 11 formed in the compressor housing 6 in the expansion chamber 18 communicating with the extraction hole 11.
In this case, the opening of the extraction hole 11 and the blade thickness of the compressor blade 4a passing through the opening of the extraction hole 11 are substantially the same size, and the opening of the extraction hole 11 is instantaneously shielded and opened by the compressor blade 4a. It has become.

  From the above, according to the second embodiment, since the opening of the extraction hole 11 and the blade thickness of the compressor blade 4a are substantially the same size, when the compressor blade 4a passes through the opening of the extraction hole 11, the extraction hole 11 Since the sound pressure level captured by the microphone 12 is 0, and the sound pressure level thereafter passes from the L level through the opening of the extraction hole 11, as shown in FIG. The sound pressure level is H level (see FIG. 6).

Here, the rotation state detection unit 13 can be configured by an amplifier 19, an automatic gain control circuit 15 (AGC), a counter 21, and a display unit 22 in order to obtain a measurement configuration using the microphone 12. .
Here, the automatic gain control circuit increases the gain of the amplifier when the input signal strength is small with respect to a certain reference output signal strength, and decreases the amplification gain when the input signal strength is large to optimize the signal size. I am trying.
Here, the sound pressure signal captured by the microphone 12 is amplified by the amplifier 19, the signal magnitude is optimized by the automatic gain control circuit 15, and then the sound pressure pulse is counted by the counter 21. It is to display. The display unit 22 displays the rotation speed of the turbocharger 1.

  As described above, the rotational speed of the turbocharger 1 can be measured also in the second embodiment. In addition, since the rotation state detection part 13 in the rotation state detection apparatus 10 of 2nd Embodiment can be displayed as the rotation speed of the turbocharger 1 by the display part 22, for example, the display part 22 is displayed on the instrument panel of a driver's seat. It is equipped as standard and can let the driver know the operating state of the turbocharger 1.

  As described above, in the first and second embodiments, the opening of the take-out hole 11 is formed in accordance with the inclination in the rotation axis direction of the blade height upper end edge of the compressor blade 4a. The upper edge of the blade height of 4a can reliably pass through the take-out hole 11, and can instantly shield and open the take-out hole 11. Accordingly, the high-pressure supercharged air in the compressor housing 6 can be taken out as pressure fluctuations through the take-out hole 11.

  Furthermore, in order to catch the pressure fluctuation more reliably, as shown in FIG. 7, a plurality of extraction holes 11 can be provided along the upper edge of the blade height of the compressor blade 4a. As a result, the pressure receiving area can be expanded, and an increase in the signal related to pressure fluctuation can be achieved. Further, as shown in FIG. 8, the pressure receiving area is expanded and the signal related to the pressure fluctuation can be obtained by making the opening of the rectangular take-out hole 11 longer along the upper edge of the blade height of the compressor blade 4a. Can be increased.

As described above, the present invention has been described with reference to the first and second embodiments in which the high-pressure supercharged air in the compressor housing 6 is extracted as the pressure fluctuation through the extraction hole 11.
That is, there is a pressure difference between the space on the front side in the rotational direction of the compressor blade 4a and the space on the rear side in the rotational direction, and the pressure difference between the front and rear surfaces of the compressor blade 4a The number of rotations can be measured.

Therefore, the rotation state detection unit 13 here detects not only the pressure fluctuation (thin solid line) for each compressor blade 4a, but also the waviness (see FIG. 9) indicated by a thick solid line that fluctuates for each predetermined long cycle. An undulation detecting unit can be provided. FIG. 9 shows a pressure waveform when the compressor flow rate is reduced while maintaining the turbo rotation speed constant.
Although the detailed description is omitted, the swell detector can detect the swell that fluctuates every predetermined period by using FFT or a low-pass filter.
When the pressure fluctuation of each compressor blade 4a detects a longer period of swell than the fluctuation of each blade, it detects a failure leading to the destruction of the compressor blade, such as pre-surge (swing stall) or surging generated on the extension line. There is a big characteristic that you can.

  The turbocharger rotation state detection apparatus of the present invention has versatility in turbochargers of any engine equipment.

DESCRIPTION OF SYMBOLS 1 Turbocharger 2 Rotor shaft 3 Turbine wheel 4 Compressor wheel 4a Compressor blade 5 Turbine housing 6 Compressor housing 6s Shroud part 7 Diffuser 8 Scroll 10 Rotation state detection apparatus 11 Extraction hole 12 Pressure fluctuation detection part 13 Rotation state detection part 14 Detection signal amplifier 15 Automatic Gain Control Circuit 16 Waveform Shaping Circuit 17 Counter 18 Expansion Room 19 Amplifier 22 Display Unit

Claims (6)

In a turbocharger rotation state detection device comprising a turbine wheel and a compressor wheel connected with a rotor shaft as a rotation axis, a turbine housing that houses the turbine wheel, and a compressor housing that houses the compressor wheel,
An extraction hole formed in the shroud portion of the compressor housing located on the downstream side of the compressor blades of the compressor wheel so as to penetrate from the outside of the compressor housing toward the inside of the compressor housing;
A pressure fluctuation detecting unit for detecting pressure fluctuation in the compressor housing, which is taken out in the take-out hole;
A rotation state detection unit that detects the rotation speed or rotation variation of the compressor wheel based on the detection signal of the pressure fluctuation detection unit , and
The turbocharger rotation state detection device is characterized in that the opening of the take-out hole is formed in accordance with the inclination in the rotation axis direction of the blade height upper end edge of the compressor blade .   2. The turbocharger rotation state detection device according to claim 1, wherein the pressure fluctuation detection unit is disposed in an expansion chamber formed in the compressor housing and communicating with the extraction hole. 3. The pressure fluctuation detecting unit is composed of a semiconductor pressure sensor, turbocharger rotational state detecting apparatus according to claim 1, wherein.   The turbocharger rotation state detection device according to claim 1, wherein the pressure fluctuation detection unit includes a sound pressure sensor. The circumferential width of the take-out hole is substantially the same as the blade thickness of the compressor blade, and the pressure fluctuation detection unit has a space on the front side in the rotation direction of the compressor blade that passes through the take-out hole, and on the rear side in the rotation direction. The turbocharger rotation state detection device according to any one of claims 1 to 4, wherein a pressure difference in the space is detected. The turbo according to any one of claims 1 to 5 , wherein the rotation state detection unit includes a swell detector that detects a swell that changes every predetermined period from a pressure change of each compressor blade. Charger rotation state detection device.

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