WO2016157442A1

WO2016157442A1 - Device for estimating angular speed, device for estimating energy, and device for estimating variation between cylinders

Info

Publication number: WO2016157442A1
Application number: PCT/JP2015/060228
Authority: WO
Inventors: 健五友成; 和一生司; 宏則岩元
Original assignee: 株式会社電子応用
Priority date: 2015-03-31
Filing date: 2015-03-31
Publication date: 2016-10-06

Abstract

A device for detecting angular speed, for estimating the angular speed of a compressor rotor (2) having a plurality of blades (22), is provided with a passage detection device (5) for detecting the passing of each blade through a predetermined angle position in a housing (3) for accommodating the compressor rotor, and a calculation device (6) for calculating the angular speed of the compressor rotor. The calculation device is provided with an angular speed calculation unit for calculating the time interval taken for at least two specific pairs of blades among the plurality of blades to pass through the predetermined angle position on the basis of the output of the passage detection device, and calculating the instantaneous angular speed of the compressor rotor on the basis of the calculated time interval.

Description

Angular velocity estimation device, energy estimation device, and inter-cylinder variation estimation device

The present invention relates to an angular velocity estimation device that estimates an angular velocity of a compressor rotor used in a compressor, an energy estimation device that estimates the kinetic energy of the rotor using the angular velocity estimation device, and an internal combustion engine using the energy estimation device The present invention relates to an inter-cylinder variation estimation apparatus.

Conventionally, various methods have been proposed for detecting the rotational speed of a compressor rotor used in a compressor, for example, the compressor rotor (impeller) of an exhaust turbocharger of an internal combustion engine. The rotation speed of the compressor rotating body calculated in this way is used to monitor whether the rotation speed of the compressor rotating body is excessive.

As an apparatus for detecting the rotational speed of such a compressor rotating body, for example, a pressure sensor that outputs a signal in response to pressure fluctuation caused by passage of a blade of the compressor rotating body in a compressor housing that houses the compressor rotating body. Have been proposed (for example, Patent Document 1). In particular, the apparatus described in Patent Document 1 analyzes the frequency of the signal from the pressure sensor, measures the fundamental frequency of the signal, and calculates the rotational speed of the compressor rotor based on this fundamental frequency. According to Patent Document 1, it is said that the rotation speed of the compressor rotating body can be detected by using the pressure sensor regardless of the thickness of the blade of the compressor rotating body.

Further, as another device for detecting the rotation speed of the compressor rotating body, a rotation speed sensor for detecting the passage of the blade by generating an eddy current in the blade of the compressor rotating body is used in the compressor housing that houses the compressor rotating body. What has been proposed. In particular, the rotation speed sensor described in Patent Document 2 includes a coil that generates a magnetic field when energized, and a U-shaped core that emits the magnetic field generated by the coil to a space through which the blade passes. According to Patent Document 2, by using such a rotational speed sensor, it is possible to detect the passage of the blade even if the detection target is as thin as the blade. In the apparatus of Patent Document 2, one pulse is generated every time the number of blade passage detections reaches a predetermined number, and the number of rotations is detected based on this pulse.

JP 2003-240788 A JP 2015-34780 A

However, the devices described in Patent Document 1 and Patent Document 2 described above can detect the average rotational speed of the compressor rotor, but can accurately detect the instantaneous angular velocity of the compressor rotor. could not. That is, even if the angular velocity of the compressor rotor changes during one rotation of the compressor rotor, this cannot be accurately detected.

Therefore, in view of the above problems, an object of the present invention is to provide an angular velocity detection device that can accurately detect an instantaneous angular velocity of a compressor rotor.

In order to solve the above-described problem, according to the first aspect of the present invention, there is provided an angular velocity detection device for estimating an angular velocity of a compressor rotating body having a plurality of blades, and each of predetermined angular positions in a housing that houses the compressor rotating body is determined. A passage detection device that detects that a blade has passed, and a calculation device that calculates an angular velocity of the compressor rotor, wherein the calculation device includes at least one of the plurality of blades based on an output of the passage detection device. An angular velocity calculation unit is provided that calculates a time interval between two specific pairs of blades passing through the predetermined angular position, and calculates an instantaneous angular velocity of the compressor rotor based on the calculated time interval. An angular velocity detection device is provided.

In the second invention, in the first invention, the pair of blades are two adjacent blades.

According to a third aspect, in the first or second aspect, the calculation device calculates the instantaneous angular velocity calculated by the angular velocity calculation unit based on a shape error of a blade of the compressor rotating body. When the body is rotated at a constant angular velocity, the angular velocity calculated based on the time interval between the passage of a plurality of pairs of blades is corrected so that they coincide with each other as the instantaneous angular velocity of the compressor rotor An angular velocity correction unit for calculating is further provided.

According to a fourth aspect, in the first or second aspect, the calculation device further includes an angular velocity correction unit that calculates an instantaneous angular velocity by multiplying the angular velocity calculated by the angular velocity calculation unit by a correction coefficient. The correction coefficient is an instantaneous angular velocity calculated by the angular velocity calculation unit based on a time interval during which a plurality of pairs of blades pass when the compressor rotating body is rotated at a constant angular velocity. The instantaneous angular velocities calculated by multiplying the corresponding correction coefficients are set to be equal to each other.

According to a fifth aspect, in any one of the first to fourth aspects, the passage detection device is an eddy current sensor or an electromagnetic pickup sensor.

According to a sixth aspect of the invention, there is provided energy detection for calculating instantaneous kinetic energy of a rotating body including the compressor rotating body based on the angular velocity estimated by the angular velocity detecting device according to any one of the first to fifth inventions. An apparatus is provided.

According to a seventh aspect of the present invention, there is provided an inter-cylinder variation estimation device for estimating variation related to combustion between cylinders in an internal combustion engine having an exhaust turbocharger and having a plurality of cylinders, the energy detection device according to the first aspect of the invention. An internal combustion engine comprising: a variation estimation unit that estimates variation between cylinders based on the instantaneous kinetic energy calculated by the energy detection device; and the compressor rotating body is a compressor rotating body of the exhaust turbocharger. An engine cylinder-to-cylinder variation estimation apparatus is provided.

According to an eighth aspect, in the seventh aspect, the instantaneous kinetic energy of the rotating body calculated by the energy detecting device is a plurality of times during one cycle of the internal combustion engine according to the number of cylinders of the internal combustion engine. The variation estimator calculates values of arbitrary parameters obtained from the transition of kinetic energy while the kinetic energy varies up and down once within the same cycle of the internal combustion engine. The inter-cylinder variation is estimated by comparison.

According to the present invention, there is provided an angular velocity detection device that can accurately detect an instantaneous angular velocity of a compressor rotor.

FIG. 1 is a sectional view schematically showing a compressor of an exhaust turbocharger of an internal combustion engine. FIG. 2 is a plan view schematically showing a compressor rotor (impeller) used in the compressor shown in FIG. FIG. 3 is a diagram schematically showing the detection principle by the eddy current sensor. FIG. 4 is a diagram showing the transition of output when an eddy current sensor is used as the passage detection sensor. FIG. 5 is a diagram showing transition of output when an eddy current sensor is used as the passage detection sensor. FIG. 6 is a diagram showing the transition of the angular velocity detected while the compressor rotor rotates once. FIG. 7 is a plan view similar to FIG. 2, schematically showing the compressor rotor. FIG. 8 shows a measurement result when the measurement is actually performed in a state where the compressor rotating body is rotated at a constant angular velocity. FIG. 9 is a flowchart showing a control routine of the instantaneous angular velocity detection process described above. FIG. 10 is a schematic overall view of an internal combustion engine having an exhaust turbocharger. FIG. 11 is a diagram showing the transition of the angular velocity and the kinetic energy of the rotating body of the exhaust turbocharger in one cycle of the internal combustion engine shown in FIG. FIG. 12 is a diagram showing the transition of the angular velocity and kinetic energy of the rotating body of the exhaust turbocharger in one cycle of the internal combustion engine shown in FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same reference numerals are assigned to similar components.

<Compressor configuration>
First, with reference to FIG.1 and FIG.2, the compressor in which the angular velocity detection apparatus which concerns on 1st embodiment is used is demonstrated. FIG. 1 is a cross-sectional view schematically showing a compressor of an exhaust turbocharger of an internal combustion engine, and the angular velocity detection device of the present invention for detecting the angular velocity of a compressor rotating body is used for this compressor. FIG. 2 is a plan view schematically showing a compressor rotating body (impeller) used in the compressor shown in FIG.

As shown in FIG. 1, the compressor 1 includes a compressor rotating body 2 that compresses gas and a housing 3 that houses the compressor rotating body 2.

The compressor rotor 2 is connected to a turbine (not shown) of an exhaust turbocharger via a shaft 4 and extends from the surface of the center body 21 in the radial direction or the axial direction of the compressor rotor 2. A plurality of blades 22. The central body 21 is fixed to the shaft 4 so that the axis L thereof is coaxial with the axis of the shaft 4.

Further, as can be seen from FIG. 2, the compressor rotor 2 of the present embodiment has twelve blades 22 having the same shape and arranged at equal intervals. In FIG. 2, blades are numbered (B1 to B12) for easy understanding of the description in this specification. The number of blades 22 is not limited to 12 and may be more than 12 or less than 12. Further, in the compressor rotating body 2 of the present embodiment, the plurality of blades 22 are configured to extend in the radial direction or the axial direction of the compressor rotating body 2. However, the plurality of blades 22 may have any shape such as a curved shape as long as the fluid flowing into the compressor 1 can be compressed. Further, the blades 22 are not necessarily arranged at equal intervals, and a part or all of the blades 22 may be configured to have a shape different from that of the other blades.

Referring to FIG. 1, the housing 3 has a central passage 31 that extends through the center of the housing 3 and an annular passage 32 that extends around the central passage 31. One end of the central passage 31 is open and constitutes an inlet 33 through which fluid flows. An annular passage 32 is disposed around the other end of the central passage 31, and the compressor rotor 2 is disposed in the central passage 31 inside the annular passage 32. Therefore, the fluid flowing in from the inlet 33 flows out through the central passage 31 and into the annular passage 32 via the compressor rotor 2.

The compressor rotating body 2 can rotate around its axis L in the housing 3. Further, the compressor rotor 2 is configured such that, when rotated, the radial end of the blade 22 moves in the circumferential direction along the inner peripheral surface with a slight gap from the inner peripheral surface of the housing 3. The

<Passage detection sensor>
In the present embodiment, the housing 3 is provided with a passage detection sensor 5 that detects that the blade 22 has passed through a predetermined angular position in the housing 3. That is, the passage detection sensor 5 detects that the blade 22 has passed in front of the detection unit of the passage detection sensor 5. In the present embodiment, the passage detection sensor 5 is disposed so as to face the radial end surface 22a of the blade 22 of the compressor rotor 2 and to extend in the normal direction of the radial end surface 22a of the blade 22. The passage detection sensor 5 is disposed in the housing 3 on the inlet side of the compressor rotator 2. In the example shown in FIG. 1, the passage detection sensor 5 is disposed in the housing 3 adjacent to the inlet side end face 22 b of the blade 22 of the compressor rotor 2. The passage detection sensor 5 is connected to an electronic control unit (ECU) 6 that also functions as a calculation device for calculating the angular velocity of the compressor rotor, and an output signal of the passage detection sensor 5 is input to the ECU 6.

Here, the blade 22 of the compressor rotor 2 gradually increases in temperature from the inlet side toward the outlet side. This is because the fluid flowing through the compressor rotor 2 is pressurized from the inlet side toward the outlet side. In the present embodiment, the passage detection sensor 5 is disposed in the housing 3 on the inlet side of the compressor rotator 2, and thus is disposed in a relatively low temperature region. For this reason, the influence of heat on the passage detection sensor 5 can be reduced.

In the present embodiment, an eddy current sensor is used as the passage detection sensor 5. The eddy current sensor is a sensor that generates an output corresponding to the distance between the sensor detection unit and the metal material to be measured. The detection principle of the eddy current sensor will be briefly described below with reference to FIG.

The eddy current sensor 5 has a coil 25 that generates a magnetic field by an alternating excitation current at its detection part. When the blade 22 passes through the magnetic field X generated by the coil 25, an eddy current Y is generated in the blade 22 so as to cancel the magnetic field generated by the coil 25. The strength of the magnetic field X changes due to the eddy current generated in the blade 22, and as a result, the value of the current flowing through the coil 25 changes. Therefore, in the eddy current sensor 5, since the current value flowing through the coil 25 changes when the blade 22 passes through the magnetic field, the passage of the blade 22 is detected by detecting the current value (output value) flowing through the coil 25. Like to do. Specifically, it is determined that the time when the output of the eddy current sensor 5 reaches a peak is the time when the blade 22 passes in front of the detection unit of the eddy current sensor 5 (that is, a predetermined angular position). I have to.

Note that any sensor may be used as a passage detection sensor for detecting the passage of the blade 22 as long as the passage of the blade 22 can be detected. An example of such a sensor is an electromagnetic pickup (MPU) sensor. The MPU sensor is a sensor having a magnet and a detection coil in its detection unit. In such an MPU sensor, when a blade, which is a magnetic body, approaches or separates from the MPU sensor, the magnetic flux penetrating the detection coil changes, and the induced electromotive force of the detection coil changes accordingly. Thereby, the passage of the blade 22 in front of the detection unit of the MPU sensor can be detected. In the following description, a case where an eddy current sensor is used as the passage detection sensor will be described.

FIG. 4 is a diagram showing the transition of output when an eddy current sensor is used as the passage detection sensor 5. 4A shows a transition when the rotation speed of the compressor rotor 2 is relatively slow, and FIG. 4B shows a transition when the rotation speed of the compressor rotor 2 is relatively slow.

As described above, in the eddy current sensor 5, the output value increases as the distance between the detection unit of the eddy current sensor 5 and the object (for example, the blade 22) passing therethrough becomes shorter. Therefore, when the blade 22 passes in front of the detection unit of the eddy current sensor 5, the output of the eddy current sensor 5 increases rapidly. Therefore, the output changed into a convex shape in FIG. 4 means that the blade 22 has passed. The numbers in FIG. 4 indicate the numbers (B1 to B12) of the blades 22 that have passed in front of the detection unit of the passage detection sensor 5.

As shown in FIG. 4A, when the rotational speed of the compressor rotor 2 is relatively slow, the output value of the eddy current sensor 5 suddenly rises and falls as the blade 22 passes, The period during which two adjacent blades 22 pass is kept constant at a low value.

On the other hand, as shown in FIG. 4B, when the rotational speed of the compressor rotor 2 is relatively high, before the output value of the eddy current sensor 5 that has risen with the passage of one blade 22 has fallen completely. In addition, the output value starts to rise as the next blade 22 passes. Therefore, as shown in FIG. 4B, the output value of the eddy current sensor 5 is not maintained constant even during the period during which two adjacent blades 22 pass. However, even in this case, since the time when the output value of the eddy current sensor 5 becomes maximum indicates the passage of the blade 22, the blade 22 has passed in front of the detection unit of the eddy current sensor 5. Can be accurately detected.

<Instantaneous angular velocity detection>
Incidentally, the instantaneous angular velocity of the compressor rotator 2 also changes while the compressor rotator 2 makes one revolution. Thus, when the instantaneous angular velocity that changes even during one rotation can be detected, the instantaneous kinetic energy of the compressor rotor 2 can be calculated based on this. When the instantaneous kinetic energy of the compressor rotor 2 can be calculated, for example, combustion variations between cylinders of the internal combustion engine can be estimated based on this, as will be described later. That is, the inventors of the present application detect various instantaneous parameters (for example, for example, determining the operating state of the compressor itself and the engine using the compressor by detecting the instantaneous angular velocity of the compressor rotor 2. It has been found that the above-mentioned value of combustion variation between cylinders can be calculated.

Therefore, in this embodiment, the angular velocity calculation unit of the ECU 6 calculates the instantaneous angular velocity of the compressor rotor 2 based on the output of the eddy current sensor 5. Below, the calculation method of the instantaneous angular velocity of the compressor rotary body 2 is demonstrated using FIG. In the example shown in FIG. 4, the time t1 is the time when the output of the eddy current sensor 5 shows a peak as the first blade B1 passes in front of the eddy current sensor 5. Similarly, when the second blade B2, the third blade B3, and the fourth blade B4 pass in front of the eddy current sensor 5 and the output of the eddy current sensor 5 shows a peak, they are time t2, t3, and t4, respectively. .

In this case, the time interval Δt1 from when the first blade B1 passes in front of the eddy current sensor 5 to when the second blade B2 passes can be expressed as t2-t1. On the other hand, in this embodiment, since 12 blades are provided at equal intervals, the angular interval between the first blade B1 and the second blade B2 is basically 2π / 12 (rad). . Therefore, the instantaneous angular velocity of the compressor rotating body 2 from when the first blade B1 passes through the second blade B2 before the eddy current sensor 5 (hereinafter referred to as “instantaneous angular velocity after passing through the first blade”). ) 1 is calculated as 2π / (12 × Δt1).

Similarly, the time interval Δt2 between the second blade B2 and the third blade B3 can be expressed as t2-t3, and the time interval Δt3 between the third blade B3 and the fourth blade B4 can be expressed as t3-t4. . Therefore, the instantaneous angular velocity ω2 of the compressor rotating body 2 from the passage of the second blade B2 to the passage of the third blade B3 in front of the eddy current sensor 5, that is, the instantaneous angular velocity after passing through the second blade B2. ω2 is calculated as 2π / (12 × Δt2). Similarly, the instantaneous angular velocity ω3 of the compressor rotating body 2 from the passage of the third blade B3 to the passage of the fourth blade B4 in front of the eddy current sensor 5, that is, the instantaneous moment after the passage of the third blade B3. The angular velocity ω3 is calculated as 2π / (12 × Δt3).

Therefore, according to the present embodiment, when the number of the blade 22 is represented by i, a pair of adjacent blades (that is, the i-th blade Bi and the (i + 1) th blade B (i + 1)) based on the output of the eddy current sensor 5. ) During the passage in front of the eddy current sensor 5 is calculated. Based on the time interval Δti calculated in this way and the angular interval between adjacent pairs of blades, the instantaneous angular velocity ωi after passing through the i-th blade Bi, that is, the instantaneous angular velocity of the compressor rotor 2. ωi is calculated. Specifically, the angular interval αi between adjacent pairs of blades (i-th blade Bi and (i + 1) -th blade B (i + 1)) as expressed by the following formula (1) is calculated as a time interval between these blades. By dividing by Δti, the instantaneous angular velocity ωi after passing through the i-th blade is calculated. In the compressor rotor 2 in which n blades are provided at equal intervals in the circumferential direction, the instantaneous angular velocity ωi is calculated by the following equation (2).
ωi = αi / Δti (1)
ωi = 2π / (n × Δti) (2)

In the above-described embodiment, the instantaneous angular velocity ω is based on the time interval at which a pair of adjacent two blades 22 pass a predetermined angular position in the housing 3 (before the detection unit of the eddy current sensor 5). Thus, it is calculated as an instantaneous angular velocity while both blades pass through a predetermined angular position. However, the pair of blades for calculating the instantaneous angular velocity ω may not necessarily be the two adjacent blades 22. For example, as shown in FIG. 5, the time interval Δt1 from the passage of the first blade B1 to the passage of the third blade B3, or the passage of the first blade B1 to the passage of the fourth blade B4. The instantaneous angular velocity may be calculated based on the time interval between two or more blades separated in the circumferential direction, such as the time interval Δt1 ′.

In the above embodiment, the instantaneous angular velocity is calculated based on the time interval between all adjacent pairs of blades. However, for example, the angular velocity need not be calculated based on the time intervals between all adjacent pairs of blades, such as not calculating the angular velocity based on the time interval between the second blade and the third blade. However, even in that case, it is necessary to calculate the instantaneous angular velocity at least twice during one rotation of the compressor rotor 2 (for example, in the example shown in FIG. 5, the first blade Instantaneous angular velocity based on the time interval Δt1 ′ from B1 to the fourth blade B4, and instantaneous angular velocity based on the time interval Δt2 ′ from the seventh blade B7 to the tenth blade Bs10). Thus, by calculating the instantaneous angular velocity at least twice during one rotation of the compressor rotator 2, a change in the angular velocity during one rotation of the compressor rotator 2 can be detected.

Also, in calculating the instantaneous angular velocity ω, as described above, the angular interval between the blades in a pair of blades is required as a parameter. When a plurality of blades are provided on the compressor rotor 2, these blades do not necessarily have to be arranged at equiangular intervals. In addition, even if the compressor rotor 2 is designed such that a plurality of blades are arranged at equal angular intervals, the plurality of blades are not necessarily arranged at equal angular intervals due to shape errors, as will be described later. Therefore, when calculating the instantaneous angular velocity, the instantaneous angular velocity is not calculated based on the time interval between any pair of blades, but between a specific pair of blades with known angular intervals. It is necessary to calculate the instantaneous angular velocity based on the time interval.

In summary, the angular velocity detection device according to the present embodiment includes a calculation device that calculates the instantaneous angular velocity ω of the compressor rotor 2, and a plurality of calculation devices are provided based on the output of the passage detection sensor 5. The time interval Δt during which at least two specific pairs of blades 22 of the blades 22 pass through a predetermined angular position is calculated, and the instantaneous angular velocity of the compressor rotor 2 is calculated based on the calculated time interval Δt. An angular velocity calculation unit for calculating is provided.

In the above-described embodiment, the angular velocity detection device detects the instantaneous angular velocity of the compressor rotor for the compressor of the exhaust turbocharger of the internal combustion engine. However, the angular velocity detection device can be applied to any compressor as long as the compressor has a compressor rotating body having a plurality of blades. Therefore, for example, it is applicable also to an axial flow type compressor etc.

<Compressor rotor shape error>
Here, FIG. 6 shows an example in which the instantaneous angular velocity of the compressor rotator 2 is calculated by the angular velocity calculator configured as described above in a state where the compressor rotator 2 is rotated at a constant angular velocity. In FIG. 6, the horizontal axis represents the blade number, and the vertical axis represents the instantaneous angular velocity after passing through the blade of the corresponding blade number.

In the example shown in FIG. 6, the compressor rotor 2 is rotated at a constant angular velocity. Therefore, at this time, the calculated instantaneous angular velocity ω should be a constant value. However, actually, as shown in FIG. 6, the calculated instantaneous angular velocity ω is not necessarily constant after passing through each blade 22. For example, in the example shown in FIG. 6, the instantaneous angular velocity after passing through the second blade is slower than the instantaneous angular velocity after passing through the first blade.

In this regard, the inventors of the present application conducted extensive research and found that the calculated instantaneous angular velocity ω does not have a constant value because the shape error of the blade 22 of the compressor rotor 2 (within the shape tolerance range). We found out that there was a main cause of error. In other words, it has been found that there is a shape error for each solid in the compressor rotor 2, and this shape error causes an error in the instantaneous angular velocity calculated by the angular velocity calculator. Hereinafter, the relationship between the calculated instantaneous angular velocity ω and the shape error of the blade 22 will be described with reference to FIG.

FIG. 7 is a plan view similar to FIG. 2, schematically showing the compressor rotor. 7 indicates the shape of the blade 22 when the blade 22 of the compressor rotor 2 is formed as designed. In the example shown in FIG. 7, the plurality of blades 22 are designed to have the same shape at regular intervals. In the example shown in FIG. 7, it can be seen that the second blade B2 and the tenth blade B10 have a shape error with respect to the designed blade shape. Specifically, the second blade B2 has a shape shifted to the first blade side in the circumferential direction with respect to the design shape. Further, the tenth blade B10 has a shape shifted radially outward from the design shape.

¡If there is an error in the blade shape, the angle interval α between the blades changes. In the example shown in FIG. 7, the shape of the second blade B2 is a shape that is shifted in the circumferential direction with respect to the designed shape. As a result, in the region facing the eddy current sensor 5, the actual angular interval between the first blade B1 and the second blade B2 is α1, which is smaller than the design value β1. Conversely, the actual angular interval between the second blade B2 and the third blade B3 is α2, which is larger than the design value β2. Accordingly, the actual angular interval α1 between the first blade B1 and the second blade B2 is smaller than the actual angular interval α2 between the second blade B2 and the third blade B3. On the other hand, in calculating the angular velocity, a design value is used instead of the actual angular interval between the blades. Therefore, even if the compressor rotor 2 rotates at a constant rotation angle, the instantaneous angular velocity ω1 based on the time interval Δt1 from the first blade B1 to the second blade B2 is the second blade B2 to the third blade. It is calculated as being faster than the instantaneous angular velocity ω2 based on the time interval Δt2 up to B3. As a result, as shown in FIG. 6, the instantaneous angular velocity after passing through the first blade B1 is calculated to be faster than the instantaneous angular velocity after passing through the second blade B2.

Further, in the example shown in FIG. 7, the tenth blade B10 has a shape that is shifted outward in the circumferential direction with respect to the design shape. As a result, the actual angular interval between the ninth blade B9 and the tenth blade B10 is α9 which is smaller than the design value β9. In addition, the actual angular interval between the tenth blade B10 and the eleventh blade B11 is α10 which is larger than the design value β10. As a result, even if the compressor rotor 2 rotates at a constant rotation angle, the instantaneous angular velocity after passing through the ninth blade B9 is calculated to be faster than the instantaneous angular velocity after passing through the tenth blade B10. .

FIG. 7 shows an example of a shape error in which the shape of the blade is totally shifted in the circumferential direction or the radial direction. However, the shape error in the blade includes various errors in addition to the above-described shape error, such as an error in the axial direction of the compressor rotor 2 and an error in the curved shape of the blade. When such a shape error occurs in the blades, the angular velocity between the blades cannot be properly detected.

<Correction based on blade shape error>
Therefore, in the embodiment of the present invention, the angular velocity correction unit of the ECU 6 causes a plurality of pairs of blades 22 when the compressor rotor 2 is rotated at a constant angular velocity based on the shape error of the blades of the compressor rotor 2. A value obtained by correcting the instantaneous angular velocity calculated by the angular velocity calculating unit so that the instantaneous angular velocities calculated based on the time interval between the passages coincide with each other is calculated as the instantaneous angular velocity of the compressor rotor 2. Like to do.

Specifically, the instantaneous angular velocity calculated by the angular velocity calculator is corrected based on the angular interval between the blades in the region facing the detector of the eddy current sensor 5. In particular, the instantaneous angular velocity calculated by the angular velocity calculator is corrected based on the angular interval between the portions of the blade 22 that are determined to have passed by the eddy current sensor 5. In the region where the angular interval between the blades 22 is smaller than the design value, correction is performed so that the instantaneous angular velocity calculated by the angular velocity calculating unit is reduced. On the contrary, in the region where the angular interval between the blades 22 is larger than the design value, the instantaneous angular velocity calculated by the angular velocity calculating unit is corrected so as to increase.

For example, in the example shown in FIG. 7, the actual angular interval α1 between the first blade B1 and the second blade B2 is smaller than the design value β1, so that after passing through the first blade B1 calculated by the angular velocity calculation unit. The instantaneous angular velocity is corrected so as to be reduced by the angular velocity correction unit. On the other hand, since the actual angular interval α2 between the second blade B2 and the third blade B3 is larger than the design value β2, the instantaneous angular velocity after passing through the second blade B2 calculated by the angular velocity calculator is Correction is performed in the correction unit so as to increase.

In particular, the ratio between the actual angular interval between the blades 22 and the design value is equal to the ratio between the angular velocity calculated by the angular velocity calculating unit and the actual angular velocity. Therefore, in the present embodiment, the shape of the blade 22 of the compressor rotating body 2 is measured, and the actual angular interval αi between the pair of blades 22 and the design value βi based on the measured shape of each blade 22. The ratio is calculated as a correction coefficient ki (ki = αi / βi). Here, i is the pair number of the blade 22 and represents the pair of the i-th blade and the next blade. The corrected instantaneous angular velocity ωmi is calculated by the following equation (3) by multiplying each instantaneous angular velocity ωi calculated by the angular velocity calculating unit by the correction coefficient ki calculated in this way.
ωmi = ki × ωi (3)
The instantaneous angular velocity ωmi after correction calculated in this way is calculated by removing the influence of the shape error of the blade 22, and thus has a value close to the actual angular velocity of the compressor rotor 2.

FIG. 8 shows a measurement result when the measurement is actually performed in a state where the compressor rotating body 2 is rotated at a constant angular velocity. FIG. 8A shows the transition of the angular velocity calculated during one rotation of the compressor rotor 2 when the correction by the angular velocity correction unit as described above is not performed. On the other hand, FIG. 8B shows the transition of the angular velocity calculated during one rotation of the compressor rotor 2 when the angular velocity is corrected by the angular velocity correcting unit as described above. As can be seen from FIG. 8, the angular velocity calculated during one rotation of the compressor rotator 2 before the angular velocity correction varies greatly, whereas the compressor rotator 2 rotates once after the angular velocity correction. In the meantime, the calculated angular velocity remains substantially constant. Therefore, according to this embodiment, the angular velocity of the compressor rotating body 2 can be accurately calculated by correcting the angular velocity calculated by the angular velocity calculating unit with the angular velocity correcting unit as described above.

In the above embodiment, the shape of the blade 22 of the compressor rotor 2 is measured three-dimensionally, and the correction coefficient is calculated based on the measurement result. However, the correction coefficient may be calculated based on other methods. For example, the compressor rotator 2 is rotated at a constant angular velocity by flowing a steady flow into a turbine of an exhaust turbocharger connected to the compressor rotator 2. In this state, the angular velocity calculation unit described above may detect the angular velocity of the compressor rotor 2 and calculate a correction coefficient based on the detected angular velocity.

In this case, the compressor rotates based on the time interval from when the first blade B1 passes in front of the detection unit of the eddy current sensor 5 until the first blade B1 passes in front of the detection unit of the eddy current sensor 5. The actual angular velocity ωr of the body 2 is calculated. In addition, the angular velocity ωi after passing through the i-th blade 22 is calculated by the angular velocity calculator. The correction coefficient ki for the angular velocity after passing through the i-th blade 22 is calculated by dividing the actual angular velocity ωr calculated in this way by the angular velocity ωi after passing through the i-th blade 22 (ki = ωr / ωi). ). The instantaneous angular velocity calculated by multiplying each instantaneous angular velocity ωi calculated by the angular velocity calculating unit by the correction coefficient ki calculated in this way rotates the compressor rotor 2 at a constant angular velocity. If they are, they will be equal to each other.

Therefore, in this case, the correction coefficient is the instantaneous angular velocity calculated by the angular velocity calculator based on the time interval between the passage of the plurality of pairs of blades when the compressor rotor 2 is rotated at a constant angular velocity. Furthermore, it can be said that the instantaneous angular velocities calculated by multiplying the corresponding correction coefficients are set to be equal to each other.

By calculating the correction coefficient ki in this way, three-dimensional measurement of the compressor rotor 2 is not necessary. In addition, even when the shape of the blade 22 changes over time as the compressor is used, the correction coefficient ki can be calculated while the compressor 22 is mounted on the internal combustion engine without being disassembled.

<Flowchart of instantaneous angular velocity detection process>
FIG. 9 is a flowchart showing a control routine of the instantaneous angular velocity detection process described above. The illustrated control routine is performed by interruption at regular time intervals.

First, in step S11, it is determined whether or not the passage of the blade 22 is detected by the eddy current sensor 5. If it is determined by the eddy current sensor 5 that the passage of the blade 22 has not been detected, the control routine is terminated.

On the other hand, if it is determined in step S11 that the passage of the blade 22 is detected by the eddy current sensor 5, the process proceeds to step S12. In step S12, a new blade number i is obtained by adding 1 to the blade number i. Therefore, the blade number i substantially indicates the number of the blade 22 that has passed in front of the detection unit of the eddy current sensor 5 in step S11. Next, in step S13, a time interval Δti from the previous detection of the passage of the blade 22 in step S11 to the detection of the passage of the blade 22 in step S11 is calculated.

Next, in step S14, the angular velocity ωi is calculated using the above-described equation (1) or equation (2) based on the time interval Δti calculated in step S13. Next, in step S15, a correction coefficient ki corresponding to the i-th blade stored in the ECU 6 is acquired. Thereafter, in step S16, the corrected angular velocity ωmi is calculated by the above equation (3) by multiplying the angular velocity ωi calculated in step S14 by the correction coefficient ki acquired in step S15.

Next, in step S17, it is determined whether or not the blade number i is the same as the total blade number n of the compressor rotor 2. When it is determined that the blade number i is less than the total number n of blades, the control routine is terminated. On the other hand, if it is determined in step S17 that the blade number i is the same as the total number n of blades, the process proceeds to step S18. In step S18, the blade number i is set to 0, and the control routine is terminated. In the control routine after the blade number i is set to 0, when the passage of the blade 22 is detected by the eddy current sensor 5 in step S11, the process proceeds to step S12, and the blade number i is set to 1. become.

<Use of instantaneous angular velocity>
The instantaneous angular velocity calculated in this way can be used for various purposes. Hereinafter, an example of use in the case where the angular velocity of the rotating body of the exhaust turbocharger of the internal combustion engine is detected will be described.

FIG. 10 is a schematic overall view of an internal combustion engine having an exhaust turbocharger. Referring to FIG. 10, 41 is an engine body, 42 is a combustion chamber of each cylinder, 43 is an electronically controlled fuel injection valve for injecting fuel into each

combustion chamber

42, 44 is an intake manifold, 45 is an exhaust manifold. Respectively. The intake manifold 44 is connected to the outlet of the compressor 1 of the exhaust turbocharger 47 via an intake duct 46, and the inlet of the compressor 1 is connected to an air cleaner 49 via an air flow meter 48. An electrically controlled throttle valve 50 is arranged in the intake duct 46, and a cooling device 51 for cooling intake air flowing in the intake duct 46 is arranged around the intake duct 46. On the other hand, the exhaust manifold 45 is connected to the inlet of the exhaust turbine 10 of the exhaust turbocharger 47, and the outlet of the exhaust turbine 10 is connected to an exhaust purification device 60 equipped with a three-way catalyst or the like. As can be seen from FIG. 10, the engine body 41 has four cylinders, but the number of cylinders may not be four as long as there are a plurality of cylinders.

The exhaust manifold 45 and the intake manifold 44 are connected to each other via an exhaust recirculation (hereinafter referred to as “EGR”) passage 52, and an electrically controlled EGR control valve 53 is disposed in the EGR passage 52. A cooling device 54 for cooling the EGR gas flowing in the EGR passage 52 is disposed around the EGR passage 52. On the other hand, each fuel injection valve 43 is connected to a fuel tank 56 via a fuel supply pipe 55. The fuel in the fuel tank 56 is supplied to the fuel injection valve 43 by the fuel pump 57 via the fuel supply pipes 55.

The air flow meter 8 generates an output voltage proportional to the amount of intake air, and this output voltage is input to the ECU 6. Further, as described above, the eddy current sensor 5 attached to the housing 3 of the compressor 1 is connected to the ECU 6, and the output voltage of the eddy current sensor 5 is input to the ECU. On the other hand, the ECU 6 is connected to the fuel injection valve 43, the throttle valve 50 driving device, the EGR control valve 53, and the fuel pump 57, and controls the driving thereof.

<Calculation of kinetic energy of rotating body of exhaust turbocharger>
By the way, as components that rotate in the exhaust turbocharger 47, in addition to the compressor rotator 2 described above, a turbine wheel (not shown) of the exhaust turbine 10 and a shaft that connects the compressor rotator 2 and the turbine wheel. 4 is mentioned. Therefore, the compressor rotor 2, the turbine wheel, and the shaft 4 constitute a rotor of the exhaust turbocharger 47.

The instantaneous kinetic energy KE of the rotating body of the exhaust turbocharger 47 is calculated based on the following formula (4).
^{KE = I × ω 2/2} ... (4)
In Equation (4), I is the moment of inertia of the rotating body of the exhaust turbocharger 47, and ω is the instantaneous angular velocity of the rotating body. Since the angular speed of the rotating body of the exhaust turbocharger 47 is equal to the angular speed of the compressor rotating body 2, the instantaneous kinetic energy of the rotating body is calculated by obtaining the angular speed of the compressor rotating body 2 calculated as described above. be able to.

Therefore, in this embodiment, the moment of inertia of the rotating body of the exhaust turbocharger 47 is obtained in advance. Specifically, it is obtained by calculation from the shape and material of the rotating body. Thereafter, during use of the exhaust turbocharger 47, the instantaneous angular velocity ω of the compressor rotor 2 is calculated as described above, and the exhaust turbocharger 47 of the exhaust turbocharger 47 is calculated by the above equation (4) based on the calculated angular velocity ω. The kinetic energy of the rotating body is calculated. In the present embodiment, as described above, the instantaneous angular velocity of the compressor rotor 2 can be accurately calculated by performing the correction by the angular velocity correction unit, so the instantaneous kinetic energy of the rotor of the exhaust turbocharger 47 can be calculated. It can be calculated accurately.

<Calculation of variation between cylinders>
As described above, when the instantaneous kinetic energy of the rotating body of the exhaust turbocharger 47 can be accurately calculated, the torque difference between the cylinders of the internal combustion engine is related to combustion based on the calculated instantaneous kinetic energy. Inter-cylinder variation can be calculated. Below, the relationship between instantaneous kinetic energy and the torque difference between cylinders is demonstrated.

FIG. 11 is a graph showing the transition of the angular velocity and kinetic energy of the rotating body of the exhaust turbocharger 47 in one cycle of the internal combustion engine shown in FIG. The horizontal axis in the figure indicates the crank angle of the internal combustion engine. The solid line in FIG. 11 indicates the kinetic energy of the rotating body of the exhaust turbocharger 47, and the broken line indicates the angular velocity of the rotating body.

As shown in FIG. 11, the angular velocity of the rotating body of the exhaust turbocharger 47 changes in accordance with the crank angle of the internal combustion engine. In the example shown in FIG. 11, when the exhaust valve of the first cylinder is opened and the exhaust gas starts to flow out of the combustion chamber 42, the exhaust gas flowing into the exhaust turbine 10 of the exhaust turbocharger 47 increases. For this reason, the angular velocity of the exhaust turbine 10 is increased, and accordingly, the angular velocity of the compressor rotor 2 is also increased. Along with this, the kinetic energy of the rotating body of the exhaust turbocharger 47 is also increased.

Thereafter, at the end of the exhaust stroke of the first cylinder, the flow rate of the exhaust gas flowing out from the combustion chamber 42 is decreased. As a result, the angular velocity of the exhaust turbine 10 is reduced, and accordingly, the angular velocity of the compressor rotor 2 is also reduced. Along with this, the kinetic energy of the rotor of the exhaust turbocharger 47 is reduced.

Therefore, as can be seen from FIG. 11, during the exhaust stroke of the first cylinder, the angular speed of the compressor rotor 2 increases and then decreases, and accordingly, the kinetic energy of the rotor of the exhaust turbocharger 47 also increases. Decrease from. Further, such angular velocity and kinetic energy similarly change in the exhaust strokes of the other cylinders. Therefore, as can be seen from FIG. 11, in the four-cylinder internal combustion engine, the angular velocity and the kinetic energy fluctuate up and down largely four times per cycle of the internal combustion engine. Therefore, the angular velocity and kinetic energy greatly fluctuate up and down a plurality of times in accordance with the number of cylinders of the internal combustion engine during one cycle of the internal combustion engine.

Considering the fourth cylinder as an example, the amount of increase in the kinetic energy of the rotor of the exhaust turbocharger 47 during the exhaust stroke of the fourth cylinder (ΔKE in FIG. 11) is from the combustion chamber 42 of the fourth cylinder. It is proportional to the exhaust energy of the exhaust gas discharged. Similarly, the increase in the kinetic energy of the exhaust turbocharger 47 during the exhaust strokes of the first cylinder, the third cylinder, and the second cylinder is discharged from the combustion chambers 42 of the first cylinder, the third cylinder, and the second cylinder, respectively. It is proportional to the exhaust energy of the exhaust gas. Here, the exhaust energy of the exhaust gas discharged from each cylinder is basically proportional to the energy generated by the combustion in the combustion chamber 7 of each cylinder, that is, the torque generated by the combustion in the combustion chamber 7 of each cylinder.

Therefore, the difference in combustion torque between the cylinders can be detected by comparing the amount of increase in the kinetic energy of the rotor of the exhaust turbocharger 47 during the exhaust stroke of each cylinder between the cylinders. Specifically, the cylinder based on the difference (ΔKE) between the minimum value of the kinetic energy of the rotating body at the start of the exhaust stroke of each cylinder and the maximum value of the kinetic energy of the rotating body during the exhaust stroke of the cylinder. The difference in combustion torque between the two can be detected. A cylinder having a large difference between the minimum value and the maximum value is determined to be a cylinder having a large combustion torque, and a cylinder having a small difference between the minimum value and the maximum value is determined to be a cylinder having a small combustion torque. As a result, the difference in combustion torque between cylinders can be minimized.

Considering the fourth cylinder as an example, the minimum value of the kinetic energy at the start of the exhaust stroke of the third cylinder where the exhaust stroke is performed before the fourth cylinder, and the kinetic energy at the start of the exhaust stroke of the fourth cylinder. The difference from the minimum value (see ΔE in FIG. 12) indicates the difference in exhaust energy between these cylinders. Therefore, it is possible to detect the difference in combustion torque between the cylinders based on the minimum value of the kinetic energy at the start of the exhaust stroke of each cylinder. Specifically, when the minimum value of the kinetic energy at the start of the exhaust stroke of a certain cylinder is large, it is determined that the exhaust energy in that cylinder is large and therefore the combustion torque is large. On the other hand, when the minimum value of the kinetic energy at the start of the exhaust stroke of a certain cylinder is small, it is determined that the exhaust energy in that cylinder is small and therefore the combustion torque is small. As a result, the difference in combustion torque between cylinders can be minimized.

In the above embodiment, the difference between the minimum value of the kinetic energy of the rotating body at the start of the exhaust stroke of each cylinder and the maximum value of the kinetic energy of the rotating body during the exhaust stroke of the cylinder, or two consecutive The difference in combustion torque between cylinders is detected based on the difference in the minimum value of the kinetic energy of the rotating body at the start of the exhaust stroke. However, the calculation of the inter-cylinder difference in combustion torque can be performed by using an arbitrary parameter (for example, between a maximum value and a minimum value) that is different from the above parameter while the kinetic energy fluctuates up and down once during the exhaust stroke of each cylinder. You may carry out based on an intermediate value etc.).

Therefore, in summary, in this embodiment, by comparing the values of arbitrary parameters obtained from the transition of the kinetic energy while the kinetic energy fluctuates up and down once in the same cycle of the internal combustion engine. It can be said that the variation between cylinders is estimated.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Compressor rotating body 3 Housing 4 Shaft 5 Eddy current sensor (passage detection sensor)
6 ECU
21 Central body 22 Blade 25 Coil 31 Central passage 32 Annular passage 33 Inlet

Claims

An angular velocity detection device for estimating an angular velocity of a compressor rotor having a plurality of blades,
A passage detection device that detects that each blade has passed through a predetermined angular position in a housing that houses the compressor rotor;
A calculation device for calculating the angular velocity of the compressor rotor,
The calculation device calculates a time interval during which at least two specific pairs of blades of the plurality of blades pass through the predetermined angular position based on an output of the passage detection device, and the calculated time An angular velocity detection device comprising an angular velocity calculation unit that calculates an instantaneous angular velocity of the compressor rotor based on the interval.
The angular velocity detection device according to claim 1, wherein the pair of blades are two blades adjacent to each other.
The calculating device calculates the instantaneous angular velocity calculated by the angular velocity calculating unit based on a shape error of the blade of the compressor rotating body when rotating the compressor rotating body at a constant angular speed. The apparatus further comprises an angular velocity correcting unit that calculates an instantaneous angular velocity of the compressor rotating body, which is corrected so that the angular velocities calculated based on a time interval during the passage of the blades coincide with each other. An angular velocity detection device described in 1.
The calculation device further includes an angular velocity correction unit that calculates an instantaneous angular velocity by multiplying the angular velocity calculated by the angular velocity calculation unit by a correction coefficient,
The correction coefficient corresponds to an instantaneous angular velocity calculated by the angular velocity calculating unit based on a time interval between the passage of a plurality of pairs of blades when the compressor rotating body is rotated at a constant angular velocity. The angular velocity detection device according to claim 1, wherein the instantaneous angular velocities calculated by multiplying the correction coefficients are set to be equal to each other.
The angular velocity detection device according to any one of claims 1 to 4, wherein the passage detection device is an eddy current sensor or an electromagnetic pickup sensor.
An energy detection device that calculates instantaneous kinetic energy of a rotating body including the compressor rotating body based on the angular velocity estimated by the angular velocity detecting apparatus according to any one of claims 1 to 5.
An inter-cylinder variation estimation device for estimating variation related to combustion between cylinders in an internal combustion engine having an exhaust turbocharger and having a plurality of cylinders,
An energy detection device according to claim 6;
A variation estimation unit that estimates the variation between the cylinders based on the instantaneous kinetic energy calculated by the energy detection device;
The inter-cylinder variation estimating apparatus for an internal combustion engine, wherein the compressor rotator is a compressor rotator of the exhaust turbocharger.
The instantaneous kinetic energy of the rotating body calculated by the energy detection device changes so as to fluctuate up and down a plurality of times according to the number of cylinders of the internal combustion engine during one cycle of the internal combustion engine,
The variation estimation unit compares the values of arbitrary parameters obtained from the transition of the kinetic energy while the kinetic energy fluctuates up and down once in the same cycle of the internal combustion engine, thereby calculating the variation between the cylinders. The inter-cylinder variation estimation apparatus for an internal combustion engine according to claim 7, wherein the estimation is performed.