JP2009270467A - Centrifugal compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain a loss by an outlet guide vane over a wide operation area, while restraining a loss in a scroll, in a centrifugal compressor. <P>SOLUTION: The outlet guide vane 17 is arranged in an inlet part of the scroll 15 on the outside of a diffuser 16 for surrounding the periphery of an impeller 12. The outlet guide vane 17 is divided into a front edge part 17A and a rear edge part 17B. An angle to the scroll 15 of the respective rear edge parts 17B is fixed to an angle of becoming minimum in an energy loss in the scroll 15. The front edge part 17A is made rotatable around a vane shaft 21. Differential pressure between both wall surfaces of the front edge part 17A is detected by a sensor 18, and an angle of the front edge part 17A is adjusted in response to this differential pressure. Thus, separation in the front edge part 17A is prevented, and the energy loss in the outlet guide vane 17 is restrained. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a centrifugal compressor that outputs a fluid delivered to an outer peripheral portion by an impeller through a scroll.

  In the centrifugal compressor, the impeller is rotated to send the fluid supplied from the axial direction toward the outer peripheral portion. In the fluid sent from the impeller, a part of kinetic energy is converted into pressure energy in the diffuser, and then supplied to a scroll provided on the outer periphery. As a diffuser, a vaned diffuser in which a large number of variable vanes are provided around an impeller is known, but the flow in the diffuser has a strong three-dimensionality, and the flow varies greatly depending on the rotation range of the impeller. For this reason, when the operating range is wide like a supercharger used for an automobile engine, a choke phenomenon due to vanes occurs in a rotational range deviated from the design point, and the supercharging efficiency is lowered.

To solve this problem, a variable guide vane that can be stored in the diffuser section is provided. In the low speed range, the guide vane is disposed in the diffuser to form a vane diffuser. A configuration as a less diffuser has been proposed (Patent Document 1).
Japanese Patent Laid-Open No. 64-066419

  On the other hand, the loss in scrolling is determined by the inflow angle into the scroll. Therefore, it is desired to rectify so that the pressurized fluid always flows from the diffuser to the scroll at a constant angle. However, since the flow in the diffuser varies depending on the rotation region as described above, it is difficult for the conventional vane diffuser to cope with the change in the flow in the diffuser while always maintaining the optimum inflow angle to the scroll.

  An object of the present invention is to obtain a centrifugal compressor that suppresses losses due to outlet guide vanes over a wide operating range while suppressing loss in scrolls.

  A centrifugal compressor according to the present invention is a centrifugal compressor that supplies a fluid delivered from an impeller to a scroll, a rear edge portion fixed at a predetermined angle with respect to the scroll, and the angle is variable. And an outlet guide vane having a front edge portion and a control section for adjusting the angle of the front edge portion.

  Since the angle of the leading edge is preferably controlled by detecting the state of the flow around the leading edge, the centrifugal compressor detects, for example, the differential pressure between both wall surfaces of the leading edge. Means for adjusting the angle of the leading edge corresponding to the differential pressure. At this time, each of the wall surfaces is provided with a pressure introducing path, and the differential pressure detecting means detects the differential pressure from the pressure in the pressure introducing path. In addition, the control unit adjusts the angle of the leading edge so that the differential pressure becomes a predetermined value or less than a predetermined value.

  Further, since the flow state around the front edge can be estimated from the moment of the front edge, the angle of the front edge may be adjusted based on the moment acting on the front edge, for example. At this time, the front edge is rotated about the shaft provided at the rear edge of the front edge, and the moment is detected based on the torque of the shaft. The control unit adjusts the angle of the leading edge so that the moment becomes a predetermined value or less than a predetermined value. Further, the control unit may adjust the angle of the front edge so that the angle of attack of the front edge becomes 0, for example.

  A vaneless diffuser is preferably provided between the outlet guide vane and the impeller.

  As described above, according to the present invention, it is possible to obtain a centrifugal compressor that suppresses loss due to outlet guide vanes over a wide operation range while suppressing loss in scrolling.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a partial cross-sectional view of a supercharger for an automobile engine using a centrifugal compressor according to an embodiment of the present invention.

  The supercharger 10 is, for example, a turbocharger, and only a part of the compressor (centrifugal compressor) 11 is shown in FIG. An impeller 13 is installed in the impeller accommodating portion 12 a of the compressor housing 12, and the impeller 13 is rotationally driven by a shaft 14. In this embodiment, the shaft 14 is connected to a turbine (not shown), and the turbine is rotated by exhaust from the engine. The impeller 13 may be configured to be driven by another power source.

  In the compressor housing 12, air is sucked from the axial direction toward the impeller 13 through the suction port 12 b, and the sucked fluid is delivered toward the outer peripheral portion by the rotation of the impeller 13. A scroll 15 is provided on the outer peripheral portion of the compressor housing 12, and the fluid sent to the outer peripheral portion by the impeller 13 is output to the intake manifold or the like via the scroll 15.

  The impeller 13 and the scroll 15 communicate with each other through a passage including the diffuser 16. The diffuser 16 is a vaneless diffuser and is disposed adjacent to the periphery of the impeller 13. A plurality of outlet guide vanes 17 are provided on the outer peripheral portion of the diffuser 16 along the circumferential direction.

  The outlet guide vane 17 is divided into a front edge portion 17A and a rear edge portion 17B. The rear edge portion 17 </ b> B is disposed at an exit portion (scroll entrance portion) of a passage communicating the impeller accommodating portion 12 a and the scroll 15, and the angle thereof is fixed with respect to the scroll 15. The angle of the trailing edge 17B is determined in consideration of minimizing energy loss in the scroll 15. On the other hand, the angle of the front edge portion 17A is variable and is adjusted according to the flow in the diffuser 16 so that the energy loss due to the outlet guide vane 17 is minimized.

  The compressor unit 11 is provided with a sensor 18 for grasping the flow state around the front edge portion 17A. A signal from the sensor 18 is sent to the ECU 19, and the ECU 19 drives the actuator 20 based on the sensor signal, and rotates the front edge portion 17A to adjust its angle. Note that, for example, a drive link mechanism used for a variable nozzle of a turbine can be applied to drive the leading edge portion 17A.

  FIG. 2 is a plan view schematically showing the arrangement of the outlet guide vanes 17, and FIG. 2 shows the arrangement of three vanes. The outlet guide vanes 17 are each arranged along the entrance of the scroll 15. As described above, the outlet guide vane 17 is divided into the front edge portion 17A and the rear edge portion 17B, and the front edge portion 17A and the rear edge portion 17B are arranged adjacent to each other to constitute one vane. To do. The trailing edge 17B is fixed to the compressor housing 12 at a predetermined (optimum) angle with respect to each scroll 15 so that energy loss in the scroll 15 is minimized. The curve L represents the shape of the edge that forms the entrance of the scroll 15.

  On the other hand, a vane shaft 21 parallel to the rotation axis of the impeller 12 is provided on the rear edge side of the front edge portion 17A, and the front edge portion 17A is pivotally attached to the compressor housing 12 via the vane shaft 21. The vane shaft 21 is connected to, for example, a link mechanism, and when the vane shaft 21 is rotated by the actuator 20 via the link mechanism, the front edge portion 17A is rotated around the vane shaft 21.

  Most of the energy loss in the outlet guide vane 17 is caused by the angle of attack of the front edge of the outlet guide vane 17 being deviated from an appropriate value and causing separation from the front edge. Therefore, in the present embodiment, in order to prevent the peeling at the front edge portion 17A, the front edge portion 17A is rotated in accordance with the flow, and the angle of attack of the front edge portion 17A is maintained at an appropriate value.

  The energy loss in the outlet guide vane 17 is minimized when, for example, the angle of attack is approximately 0 degrees, for example, the front edge portion 17A so that the differential pressure between both wall surfaces of the front edge portion 17A becomes an appropriate value. This is achieved by adjusting the angle of the front edge portion 17A or adjusting the angle of the front edge portion 17A so that the moment acting on the front edge portion 17A becomes an appropriate value.

  FIG. 3 shows an example of a differential pressure detection method in the case where the differential pressure between both wall surfaces of the leading edge 17A is detected and the angle of the leading edge 17A is adjusted based on the detected differential pressure. FIG. 3 is a schematic enlarged view of the front edge portion 17A.

  In FIG. 3, pressure introduction paths 22 and 23 for detecting static pressure are provided on both wall surfaces of the front edge portion 17A. The pressure introduction paths 22 and 23 are guided to the compressor housing 12 via, for example, the vane shaft 21 (not shown). In this case, the sensor 18 (see FIG. 1) is a pressure sensor, and the front edge portion 17A is rotated so that the differential pressure is always a predetermined value or a predetermined value or less, for example.

  In addition, when rotating the front edge part 17A so that the moment acting on the front edge part 17A becomes an appropriate value, for example, a load cell is adopted as the sensor 18 and the vane shaft 21 is attached to the load cell. Torque is detected. The angle of the front edge portion 17A is adjusted so that, for example, the moment acting on the front edge portion 17A is always a predetermined value or less than a predetermined value. Note that the sensors 18 do not have to be provided in all the outlet guide vanes 17 and may be provided in at least one outlet guide vane 17.

  As described above, according to the present embodiment, the energy loss in the outlet guide vane is adjusted by adjusting the angle of the front edge portion according to the flow while suppressing the energy loss in the scroll by the rear edge portion having the fixed angle. Can be suppressed. In particular, in a centrifugal compressor having a wide operating range, even at an operating point that is greatly deviated from the design point, separation at the front edge portion can be suppressed, and energy loss in the outlet guide vane can be sufficiently suppressed. From these, the performance of the compressor is improved.

  In this embodiment, the state of the flow around the front edge is directly detected, and the angle of the front edge is adjusted based on this, but a map in which an appropriate angle of the front edge in each operating state is obtained in advance. It is also possible to employ a configuration in which the angle of the leading edge is adjusted according to the driving state using data.

It is a fragmentary sectional view of the supercharger for motor vehicle engines using the centrifugal compressor which is one Embodiment of this invention. It is a top view which shows typically arrangement | positioning of an outlet guide vane. It is a typical enlarged view of the front edge part in which the pressure introduction path was provided.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Supercharger 11 Compressor part 12 Compressor housing 13 Shaft 14 Impeller 15 Scroll 16 Diffuser 17 Outlet guide vane 17A Front edge part 17B Rear edge part 18 Sensor 21 Vane shaft 22, 23 Pressure introduction path

Claims (9)

  A centrifugal compressor for supplying fluid delivered from an impeller to a scroll, comprising a rear edge portion fixed at a predetermined angle with respect to the scroll, and a front edge portion whose angle is variable. A centrifugal compressor comprising: an outlet guide vane; and a control unit that adjusts an angle of the front edge portion.   The centrifugal compressor includes a differential pressure detecting means for detecting a differential pressure between both wall surfaces of the leading edge, and the control unit adjusts the angle of the leading edge in accordance with the differential pressure. The centrifugal compressor according to claim 1.   The centrifugal compressor according to claim 2, wherein a pressure introduction path is provided on each of the wall surfaces, and the differential pressure detecting means detects the differential pressure from the pressure in the pressure introduction path.   4. The centrifugal compressor according to claim 3, wherein the control unit adjusts an angle of the front edge portion so that the differential pressure becomes a predetermined value or a predetermined value or less.   2. The centrifugal compressor according to claim 1, wherein the control unit adjusts an angle of the front edge portion based on a moment acting on the front edge portion.   6. The centrifugal type according to claim 5, wherein the front edge is rotated about a shaft provided at the rear edge of the front edge, and the moment is detected based on torque of the shaft. Compressor.   The centrifugal compressor according to claim 6, wherein the control unit adjusts the angle of the leading edge so that the moment becomes a predetermined value or a predetermined value or less.   The centrifugal compressor according to claim 1, wherein the control unit adjusts the angle of the front edge so that the angle of attack of the front edge becomes zero.   The centrifugal compressor according to claim 1, wherein a vaneless diffuser is provided between the outlet guide vane and the impeller.