JP2012184706A - Variable capacity compressor housing and variable capacity compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain a pressure loss of air having flowed into a diffuser chamber from an impeller storage chamber when air flowing into the impeller storage chamber is reduced.SOLUTION: A compressor housing 50 includes the diffuser chamber 54 provided outside the impeller storage chamber 52, a scroll chamber 56 formed outside the diffuser chamber 54, and a movable member 38 provided movably in the diffuser chamber 54 for partitioning a part of a communication portion between the diffuser chamber 54 and the scroll chamber 56 in a state placed in the diffuser chamber 54. At this time, the flow of the air flowing into the impeller storage chamber 52 is reduced, the movable member 38 is projected into the diffuser chamber 54. Since the capacity in the diffuser chamber 54 is reduced by the movable member 38, excessive diffusion of the air having flowed into the diffuser chamber 54 is restrained, so that pressure loss can be restrained.

Description

  The present invention relates to a variable displacement compressor housing and a variable displacement compressor.

  Patent Document 1 describes a compressor having a configuration in which guide vanes protrude into the diffuser or retract from the diffuser.

  Non-Patent Document 1 describes a compressor using a plurality of (six) bladed diffusers.

  Non-Patent Document 2 describes a diffuser with a variable vane that can change the opening degree of the air flow path in the diffuser.

Japanese Patent No. 4389442

Journal of the Gas Turbine Society of Japan, vol. 33, no. 4 (20055.7), p. 288-294 “Garrett Electric Boosting Systems Program” Federal Grant DE-FC05-000R22809, U.S. Pat. S. DOE report (2005. 6). p57-58

  However, in the configurations of Non-Patent Document 1 and Non-Patent Document 2, the configuration of the diffuser does not change in accordance with the flow rate of air flowing into the compressor. Therefore, when the flow rate of air flowing into the compressor decreases, the diffuser It was difficult to suppress the pressure loss of the air flowing into the air.

  Moreover, in the compressor of patent document 1, when the flow volume of the air which flows in into a compressor reduces, the guide blade is protruded in a diffuser, but the volume of a guide blade is so large that the volume in a diffuser is fully changed. It was difficult to suppress the pressure loss of the air flowing into the diffuser.

  The present invention has been made to solve the above problem, and is capable of suppressing pressure loss of air flowing from the impeller housing chamber into the diffuser chamber when the air flowing into the impeller housing chamber decreases. The object is to obtain a capacity compressor housing and a variable capacity compressor.

  A variable displacement compressor housing according to claim 1 of the present invention is formed along an outer periphery of an impeller housing chamber in which an impeller for accelerating the inflowing air by rotation and is communicated with the inside of the impeller housing chamber, A diffuser chamber that depressurizes and pressurizes air accelerated by the rotation of the impeller, and is formed outside the diffuser chamber and communicates with the inside of the diffuser chamber, and flows air pressurized in the diffuser chamber to the outside. The scroll chamber and the diffuser chamber are provided so as to be movable, and in a state where the scroll chamber is moved into the diffuser chamber, a part of the communication portion between the diffuser chamber and the scroll chamber is partitioned, and an air flow path of the diffuser chamber A variable volume member that reduces the volume toward the impeller chamber.

  According to the above configuration, the diffuser chamber is formed along the outer periphery of the impeller accommodating chamber, and the impeller accommodating chamber and the diffuser chamber communicate with each other so that air can flow. Furthermore, a scroll chamber is formed outside the diffuser chamber, and the diffuser chamber and the scroll chamber communicate with each other so that air can flow. Thereby, the air that has flowed into the impeller housing chamber flows into the diffuser chamber while being accelerated by the rotation of the impeller, and is pressurized by being decelerated in the diffuser chamber. The air pressurized in the diffuser chamber is collected in the scroll chamber and flows to the outside of the compressor housing.

  In this compressor housing, when air of a predetermined flow rate or more flows into the impeller accommodating chamber, the variable volume member is accommodated so that the entire diffuser chamber can be circulated. This is because the flow rate of air is large and the flow velocity of air flowing from the diffuser chamber to the scroll chamber can be secured sufficiently, so even if the pressure at the outlet to the outside is high, the surge phenomenon (cannot resist the downstream pressure) This is because a phenomenon in which a back flow of air occurs can be suppressed.

  On the other hand, when the flow rate of the air flowing into the impeller housing chamber becomes smaller (decrease) than the preset flow rate, the variable volume member is moved (projected) into the diffuser chamber. The moved volume variable member partitions a part of the communication portion between the diffuser chamber and the scroll chamber and reduces the volume of the air flow path in the diffuser chamber toward the impeller housing chamber. That is, the volume in the diffuser chamber is reduced by the volume of the protrusion of the variable volume member. As a result, the air flowing into the diffuser chamber from the impeller housing chamber is prevented from diffusing into the space beyond necessity in the diffuser chamber, so that the air can be decelerated and the pressure increased suitable for a small flow rate. Loss can be suppressed.

  In the variable displacement compressor housing according to claim 2 of the present invention, the volume variable member has a curved shape in which a distance from the impeller is increased with respect to a rotation direction of the impeller when viewed in the axial direction of the impeller. A first side surface disposed opposite to the impeller when projecting into the diffuser chamber; and a first side surface disposed outside the first side surface in the radial direction of the impeller and on an outer periphery of the diffuser chamber, and rotation of the impeller The position of the downstream end in the direction is aligned with the position of the downstream end of the first side surface, and the second side surface which becomes the inner wall surface of the scroll chamber when protruding into the diffuser chamber, the upstream end of the first side surface and the first side A third side surface connecting the upstream end of the two side surfaces.

  According to the above configuration, the flow rate of the air flowing into the impeller housing chamber is smaller (decreased) than the preset flow rate, and when the variable volume member is moved into the diffuser chamber, the impeller rotation direction (air flow) A part of the inner wall surface on the downstream side of the scroll chamber in the direction) is configured by the second side surface of the variable volume member, and the diffuser chamber and the scroll chamber are partitioned (the downstream side of the scroll chamber is isolated from the diffuser chamber). And the exit area | region where the air in a scroll chamber is discharge | released moves to the upstream exit area | region with a small cross-sectional area substantially. As a result, even if the flow rate of air is small, a flow velocity against the pressure can be secured in the exit region of the scroll chamber, and the backflow of air (surge phenomenon) can be suppressed.

  The variable displacement compressor housing according to claim 3 of the present invention is such that the position of the upstream end of the first side surface in the rotational direction of the impeller is the second side surface when the volume variable member is viewed in the axial direction of the impeller. It is arrange | positioned upstream from the position of the upstream end of.

  According to the above configuration, the position of the upstream end of the first side surface of the variable volume member when the flow rate of the air flowing into the impeller accommodating chamber is less than a preset flow rate and the variable volume member is moved into the diffuser chamber. Is disposed upstream of the position of the upstream end of the second side surface, the air flowing in the tangential direction of the impeller in the diffuser chamber hits the third side surface. Then, the air hitting the third side surface is deflected in the radial direction from the circumferential direction of the impeller. Here, the circumferential component of the air flow velocity decreases, and the velocity energy is converted into pressure energy. At the same time, since the direction of the air flow is in the radial direction, the trajectory of the air flow is shortened, that is, the air flows out through a short path. As a result, the conversion efficiency into pressure can be increased. Further, friction loss of the air flow due to contact with the variable volume member can be reduced.

  A variable displacement compressor according to a fourth aspect of the present invention is the variable displacement compressor housing according to any one of the first to third aspects, a moving means for moving the variable volume member into the diffuser chamber, Control means for operating the moving means based on information on a flow rate of air flowing into the impeller accommodating chamber and controlling movement of the variable volume member.

  According to the above configuration, when the flow rate of the air flowing into the impeller accommodating chamber is larger than the set flow rate, the control means does not operate the moving means, and the variable volume member remains accommodated. As a result, the variable displacement compressor is driven with the diffuser chamber having the maximum volume.

  On the other hand, when the flow rate of air flowing into the impeller accommodating chamber is smaller than the set flow rate, the control means operates the moving means based on the information on the flow rate of air flowing into the impeller accommodating chamber, and the volume variable member is in the diffuser chamber. Move to. The moved volume variable member partitions a part of the communication portion between the diffuser chamber and the scroll chamber and reduces the volume of the air flow path in the diffuser chamber toward the impeller housing chamber. That is, the volume in the diffuser chamber is reduced by the volume of the variable volume member. As a result, the air flowing into the diffuser chamber from the impeller housing chamber is prevented from diffusing into the space beyond necessity in the diffuser chamber, so that the air can be decelerated and the pressure increased suitable for a small flow rate. Loss can be suppressed.

  Since this invention set it as the said structure, when the air which flows in into an impeller accommodating chamber reduces, the pressure loss of the air which flowed into the diffuser chamber from the impeller accommodating chamber can be suppressed.

1 is an overall view showing a schematic configuration of a turbocharger according to an embodiment of the present invention. It is explanatory drawing which shows schematic structure of the compressor housing which concerns on embodiment of this invention. It is a perspective view which shows the external appearance of the movable member which concerns on embodiment of this invention. (A), (B) It is a fragmentary sectional view of the compressor housing which shows the movement state of the movable member which concerns on embodiment of this invention. (A) It is explanatory drawing which shows the volume of the compressor housing when the movable member which concerns on embodiment of this invention is accommodated. (B) It is explanatory drawing which shows the volume of a compressor housing when the movable member which concerns on embodiment of this invention is made to protrude in a diffuser chamber. (A), (B) It is explanatory drawing which shows the flow line of the air in the compressor housing when the movable member which concerns on a comparative example is accommodated, and the flow velocity change in a scroll exit. (A), (B) It is explanatory drawing which shows the flow line of the air in a compressor housing when the movable member which concerns on embodiment of this invention is protruded in the diffuser chamber, and the flow velocity change in a scroll exit. It is a graph which shows the change of the compressor characteristic when not providing a movable member as a comparative example when the movable member which concerns on embodiment of this invention is provided.

  An example of a variable displacement compressor housing and a variable displacement compressor according to an embodiment of the present invention will be described.

  FIG. 1 shows a schematic configuration of a turbocharger 10 as an example of the embodiment. As an example, the turbocharger 10 includes a turbine unit 20 provided in an exhaust passage 12 of a car engine (not shown), and a compressor unit 30 as an example of a variable capacity compressor provided in an intake passage 14 of the internal combustion engine. And a connecting part 40 for connecting the turbine part 20 and the compressor part 30. A rotating shaft 42 is rotatably provided in the connecting portion 40, the turbine 22 is connected to one end side (turbine portion 20 side) of the rotating shaft 42, and the other end side (compressor portion 30) of the rotating shaft 42. The impeller 32 is connected to the side.

  The turbine 22 has a plurality of turbine blades 23, and the turbine blades 23 are erected at predetermined intervals in the circumferential direction on a turbine 22 having a disk shape in plan view. The turbine 22 is rotatably accommodated in the turbine housing 24. The turbine housing 24 includes an exhaust gas inlet 26 into which the high-temperature exhaust gas G1 discharged from the internal combustion engine flows, and an exhaust gas outlet 28 from which the exhaust gas G2 after the work of rotating the turbine 22 in the turbine housing 24 is performed. Have.

  On the other hand, the impeller 32 has a plurality of impeller blades 33, and the impeller blades 33 are erected at predetermined intervals in the circumferential direction on the impeller 32 having a disk shape in plan view. The impeller 32 is rotatably accommodated in a compressor housing 50 as an example of a variable capacity compressor housing. The compressor housing 50 has an air inlet portion 34 for taking in atmospheric air A1 and an air outlet 36 from which compressed air A2 compressed by the impeller 32 rotating at high speed is ejected. The compressed air A2 ejected from the air outlet 36 is supplied to the aforementioned engine as combustion supercharged air.

  Here, when the exhaust gas G2 ejected from the exhaust gas inlet 26 collides with the turbine blade 23, the turbine 22 rotates at a high speed, and the impeller 32 connected via the rotating shaft 42 rotates at a high speed. As a result, the air flows into the compressor section 30, and the inflowed air is compressed by the rotation of the impeller 32 and is pumped from the air outlet 36 to the engine.

  As shown in FIG. 4A, the compressor unit 30 includes a compressor housing 50 in which a movable member 38 as an example of a variable volume member is movably provided, and an eccentricity as an example of a moving unit that moves the movable member 38. The cam 48, the data acquisition unit 18 for obtaining information (data) of the flow rate of air flowing into the impeller housing chamber 52 in the compressor housing 50, and the information of the air flow rate obtained by the data acquisition unit 18 are set in advance. And a control unit 16 as an example of a control means for operating the eccentric cam 48 and controlling the movement of the movable member 38 in comparison with the reference flow rate. The eccentric cam 48 is rotated (swinged) in the direction of arrow D (see FIG. 4B) by a motor (not shown), and is rotated by the control unit 16 driving this motor. Move.

  As shown in FIG. 2, the compressor housing 50 includes an impeller housing chamber 52 in which the impeller 32 is housed, a diffuser chamber 54 that is formed along the outer periphery of the impeller housing chamber 52 and communicates with the inside of the impeller housing chamber 52, A scroll chamber 56 that is formed outside the diffuser chamber 54 and communicates with the inside of the diffuser chamber 54, and a movable member 38 that is movably provided in the diffuser chamber 54.

  As shown in FIG. 4A, the impeller accommodating chamber 52 has an opening 58 formed on the side opposite to the rotary shaft 42 in the axial direction of the impeller 32 (hereinafter referred to as arrow Z direction). The part 58 is connected to the air inlet part 34 (see FIG. 1). Thus, air flows from the air inlet portion 34 through the opening 58 into the impeller accommodating chamber 52. Further, the impeller 32 is rotated by the rotation of the turbine 22 (see FIG. 1), and accelerates the air that has flowed into the diffuser chamber 54.

  As shown in FIG. 2, the diffuser chamber 54 is formed in a substantially annular shape outside the impeller accommodating chamber 52 when viewed in the arrow Z direction. The diffuser chamber 54 has a height h1 (see FIG. 4A) in the arrow Z direction that is lower than the impeller housing chamber 52, and the air that has flowed in from the impeller housing chamber 52 in an accelerated state is decelerated and added. It comes to be pressed. Further, the diffuser chamber 54 has a substantially annular bottom wall 55 when viewed in the arrow Z direction.

  The bottom wall 55 is a through-hole penetrating in the direction of the arrow Z, and is formed with a hole 57 through which the movable member 38 can move (protrude). And has a hole wall slightly larger than the outer shape of the movable member 38. In other words, the movable member 38 slides on the hole portion 57, and the gap between the movable member 38 and the hole portion 57 is eliminated so that no air leaks.

  The scroll chamber 56 is formed in a spiral shape outside the diffuser chamber 54 as viewed in the direction of the arrow Z, and collects air pressurized in the diffuser chamber 54 and flows it to the outside (downstream side). Note that the scroll start point (vortex start position) in the scroll chamber 56 when viewed in the arrow Z direction is S1.

  On the other hand, the movable member 38 is formed in a substantially crescent shape surrounded by three curved outer lines L1, L2, and L3 when viewed in the arrow Z direction. Here, in the rotation direction of the impeller 32 (hereinafter referred to as arrow R direction), the end point on the upstream side of the outline L1 coincides with the end point on the upstream side of the outline L3, and this end point is designated as point B0. To do. Further, the end point on the downstream side of the outline L3 coincides with the end point on the upstream side of the outline L2, and this end point is defined as a point B1. Furthermore, the end point on the downstream side of the outline L1 and the end point on the downstream side of the outline L2 coincide with each other, and this end point is defined as a point B2.

  The points B1 and B2 (outline L2) are arranged on the outer periphery of the diffuser chamber 54, and the point B2 is arranged in the vicinity of the scroll start point S1. Further, the point B0 is arranged upstream of the point B1 and in the vicinity of the outer periphery (outside) of the impeller 32 in the arrow R direction. The outlines L1, L2, and L3 are all in a curved state in which the central portion is convex outward in the radial direction of the impeller 32.

  Further, assuming that the rotation center position of the impeller 32 is point O, the angle of point B0-point O-point B2 is α1, and the angle of point B1-point O-point B2 is α2, point B1 has a relationship of α1> α2. Is arranged (set) so that In the movable member 38 of the present embodiment, the angles α1 and α2 are both set to be larger than 90 ° and smaller than 180 °. However, if the relationship α1> α2 is established, the angles α1 and α2 are established. This setting is not limited to this setting.

  A point on the opposite side of the movable member 38 with respect to the point O and on the outer periphery of the diffuser chamber 54 is defined as P1. Here, when the movable member 38 protrudes into the diffuser chamber 54, a second side surface 38 </ b> B described later becomes a part (lid) of the inner wall of the scroll chamber 56. And the opening part which is the exit of the air of the diffuser chamber 54 is limited to the line comprised by the point B2-point P1-point B1 on the outer periphery of the diffuser chamber 54. FIG.

  As shown in FIG. 3, the movable member 38 is a block body having a substantially crescent shape in plan view and a height of h2 in the arrow Z direction, and corresponds to a first outline L1 when viewed in the arrow Z direction. It has a side surface 38A, a second side surface 38B corresponding to the outer shape line L2, a third side surface 38C corresponding to the outer shape line L3, an upper surface 38D, and a lower surface 38E. Further, the movable member 38 moves (protrudes) into the diffuser chamber 54 only in the height h2 corresponding to the height h1 of the diffuser chamber 54 (see FIG. 4A). That is, h2> h1.

  As shown in FIG. 2, the first side surface 38 </ b> A has a curved shape in which the distance (interval) from the outer peripheral edge of the impeller 32 becomes longer toward the downstream side in the arrow R direction when viewed in the arrow Z direction. It is arranged so as to face the impeller 32 when protruding into the chamber 54. The second side surface 38 </ b> A is disposed on the outer side of the first side surface 38 </ b> A in the radial direction of the impeller 32 around the point O and on the outer periphery of the diffuser chamber 54. As described above, the inner wall surface of the scroll chamber 56 is configured when the movable member 38 protrudes into the diffuser chamber 54. The third side surface 38C is a curved surface that connects the upstream end of the first side surface 38A and the upstream end of the second side surface 38B.

  As shown in FIG. 4A, the movable member 38 is movable in the direction of the arrow Z in the hole 57 of the diffuser chamber 54 (movable to the left and right in the figure), and is not used (when accommodated). The upper surface 38D (the left end surface in the drawing) forms a part of the bottom wall 55 of the diffuser chamber 54. Further, one end (the left end in the figure) of the plurality of tension springs 46 is hooked on the lower surface 38E of the movable member 38, and the other end (the right end in the figure) of the tension spring 46 is a bracket provided on the turbocharger 10. 44. In a state where the movable member 38 is accommodated, a tensile force (return force) does not act on the movable member 38.

  Further, an eccentric cam 48 is disposed so as to face the lower surface 38E (the right end surface in the drawing) of the movable member 38. The eccentric cam 48 is spaced apart from the lower surface 38E when the movable member 38 is accommodated, and does not bias the movable member 38. At this time, the eccentric cam 48 restricts the movement of the movable member 38 in the direction opposite to the arrow Z direction, and prevents the movable member 38 from falling out of the hole 57.

  On the other hand, for example, the data acquisition unit 18 acquires data on the engine speed and the accelerator opening (the illustration of the engine and the accelerator is omitted), and flows into the impeller accommodating chamber 52 based on these data. It becomes the structure converted into the flow volume of the air to do. That is, when the accelerator opening decreases and the engine speed decreases, the flow rate (converted data) of the air flowing into the impeller accommodating chamber 52 decreases.

  When the reference flow rate is set in advance and the flow rate data sent from the data acquisition unit 18 is smaller than the reference flow rate, the control unit 16 drives a motor (not shown) as shown in FIG. Thus, the eccentric cam 48 is rotated, and the movable member 38 is moved (projected) into the diffuser chamber 54. When the flow rate data sent from the data acquisition unit 18 is larger than the reference flow rate, the control unit 16 rotates the eccentric cam 48 in the reverse direction as shown in FIG. The movable member 38 is moved (retracted).

  Next, the operation of this embodiment will be described.

  As shown in FIG. 1, in the turbocharger 10, the exhaust gas G <b> 2 ejected at a high speed from the exhaust gas inlet 26 collides with the turbine blade 23, so that the turbine 22 rotates at a high speed and is connected via a rotating shaft 42. The impeller 32 rotates at a high speed.

  Subsequently, as shown in FIG. 2, the air that has flowed into the impeller housing chamber 52 flows into the diffuser chamber 54 while being accelerated by the rotation of the impeller 32, and is pressurized by being decelerated in the diffuser chamber 54 ( Compressed). The air pressurized in the diffuser chamber 54 is collected in the scroll chamber 56 and is pumped from the air outlet 36 to an engine (not shown) outside the compressor housing 50.

  As shown in FIG. 4A, when the flow rate data sent from the data acquisition unit 18 is larger than the reference flow rate, the control unit 16 moves the movable member from the diffuser chamber 54 without rotating the eccentric cam 48. 38 is held in a retracted state. When the flow rate data sent from the data acquisition unit 18 is larger than the reference flow rate with the movable member 38 protruding into the diffuser chamber 54, the control unit 16 moves the eccentric cam 48 in the counterclockwise direction shown in the figure. Turn to. The movable member 38 is retracted from the diffuser chamber 54 by the tensile force of the tension spring 46.

  As a result, as shown in FIG. 5A, the volume (usable area) of the diffuser chamber 54 is maximized, and air can flow through the entire diffuser chamber 54. A substantial air outlet in the scroll chamber 56 is a scroll outlet 56A in the vicinity of the scroll start point S1. In FIG. 5A, the substantial scroll outlet is shown by a solid oval, and the cross section of each part in the direction of air flow in the scroll chamber 56 is shown by a broken oval.

  Further, in this state, the volume of the diffuser chamber 54 is maximum, but the pressure loss is prevented because the flow rate of air is large. That is, since the flow rate of air is large and the flow velocity of the air flowing from the diffuser chamber 54 to the scroll chamber 56 can be sufficiently secured, the surge phenomenon can be suppressed even when the pressure at the outlet to the outside is high.

  Here, as shown in FIGS. 6A and 6B, as a comparative example, when the volume of the diffuser chamber 54 is maximum and the flow rate of the flowing air is small, there are no blades in the diffuser chamber 54. Therefore, the outflow angle of the air from the impeller 32 becomes small (the outflow direction becomes close to the tangential direction), and the air flow path becomes long as indicated by the streamline Qa. And the friction loss by a long flow path increases, and the conversion rate from velocity energy to pressure energy falls. Furthermore, at the flow velocity VA at the scroll outlet 56A, it becomes impossible to resist the pressure, a surge phenomenon occurs, and it becomes difficult to flow air with a smaller flow rate. Thus, since a pressure loss occurs in the comparative example, the relationship between the air flow rate and the compressor efficiency is as shown in a graph GB as shown in FIG.

  On the other hand, as shown in FIG. 4B, in the present embodiment, when the flow rate data sent from the data acquisition unit 18 is less than the reference flow rate, the control unit 16 drives a motor (not shown) to perform eccentricity. The cam 48 is rotated in the direction of arrow D. As a result, the eccentric cam 48 comes into contact with the lower surface 38E of the movable member 38, and the movable member 38 protrudes into the diffuser chamber 54. Then, the upper surface 38 </ b> D of the protruding movable member 38 comes into contact with the inner wall of the diffuser chamber 54, thereby blocking the air flow in a part of the diffuser chamber 54.

  As a result, as shown in FIG. 5B, the volume (usable area) of the diffuser chamber 54 is minimized. The second side surface 38 </ b> B of the movable member 38 divides the communication portion (range from point B <b> 1 to point B <b> 2) between the diffuser chamber 54 and the scroll chamber 56, so that the downstream side of the scroll chamber 56 is isolated from the diffuser chamber 54. Thereby, the substantial outlet of the air in the scroll chamber 56 is located at the scroll outlet 56B in the vicinity of the upstream point B2 having a small cross-sectional area as compared with the above-described scroll outlet 56A (see FIG. 5A). It will be.

  As a result, as shown in FIG. 7B, even if the air flow rate is small, the flow velocity VB against the pressure can be secured at the scroll outlet 56B, and the backflow of air (surge phenomenon) can be suppressed. And it becomes possible to flow the air of still smaller flow rate. In FIG. 5B, the substantial scroll outlet is shown by a solid oval, and the cross section of each part in the direction of air flow in the scroll chamber 56 is shown by a broken oval.

  In the present embodiment, the volume in the diffuser chamber 54 is reduced by the volume of the movable member 38 protruding. Then, the volume of the air flow path in the diffuser chamber 54 decreases toward the impeller accommodating chamber 52 side. As a result, the air flowing into the diffuser chamber 54 from the impeller accommodating chamber 52 is prevented from diffusing into a larger space than necessary in the diffuser chamber 54, so that the air can be decelerated and the pressure increased suitable for a small flow rate. Can be performed, and pressure loss can be suppressed.

  Furthermore, in the present embodiment, as shown in FIG. 7A, the point B0, which is the position of the upstream end of the first side surface 38A, is arranged upstream of the point B1, which is the position of the upstream end of the second side surface 38B. Therefore, when the movable member 38 is moved into the diffuser chamber 54, the air flowing in the tangential direction of the impeller 32 in the diffuser chamber 54 hits the third side surface 38C. The air that hits the third side surface 38C is deflected in the radial direction from the tangential direction of the impeller 32 (or an angular direction within a predetermined range with respect to the tangential direction).

  Here, the velocity energy is converted into pressure energy by reducing the circumferential component of the air flow velocity. At the same time, since the air flow direction is in the radial direction, the air stream line Qb is shorter than the stream line Qa of the comparative example (see FIG. 6A), and the air flows out through a short path. As a result, the conversion efficiency into pressure increases. Further, since the streamline Qb is shortened, the friction loss of the air flow due to the contact with the movable member 38 can be reduced.

  FIG. 8 shows the relationship between the air flow rate and the compressor efficiency when the movable member 38 of the present embodiment is provided (graph GA) and when the movable member 38 is not provided as a comparative example (graph GB). ing.

  In the comparative example, since there is no movable member 38, a surge phenomenon occurs at the flow rate V2, and a flow rate smaller than the flow rate V2 cannot flow. Further, the compressor efficiency at the flow rate V3 (> V2) is low and is K1.

  On the other hand, in the present embodiment, since there is the movable member 38, a surge phenomenon does not occur at the flow rate V2, and air with a flow rate V1 (<V2) smaller than the flow rate V2 can flow. That is, the operating range of the compressor unit 30 (see FIG. 1) is expanded to a small flow rate region. Further, in the present embodiment, the compressor efficiency at the flow rate V3 is K2 (> K1), and the compressor efficiency can be increased as compared with the comparative example in a small flow rate region.

  In addition, this invention is not limited to said embodiment.

  The data acquisition unit 18 may obtain flow rate data directly by providing a flow rate sensor in the intake passage 14 as well as indirectly obtaining flow rate data based on the engine speed and the accelerator opening.

  Further, the movable member 38 may be projected from the upper surface side toward the bottom surface side instead of from the bottom surface side of the diffuser chamber 54. Further, an actuator may be used as the moving means of the movable member 38 instead of the eccentric cam 48.

  In addition, a plurality of movable members may be provided so as to be movable, and may be configured to move in accordance with changes in the flow rate so that the volume change in the compressor housing 50 (diffuser chamber 54) can be performed in multiple stages.

16 Control unit (an example of control means)
30 Compressor (an example of variable capacity compressor)
32 impeller 38 movable member (an example of variable volume member)
38A First side surface 38B Second side surface 38C Third side surface 48 Eccentric cam (an example of moving means)
50 Compressor housing (an example of variable capacity compressor housing)
52 Impeller accommodation chamber 54 Diffuser chamber 56 Scroll chamber

Claims (4)

Formed along the outer periphery of the impeller housing chamber in which the impeller for accelerating the inflowed air by rotation is accommodated and communicated with the inside of the impeller housing chamber, and the air accelerated by the rotation of the impeller is decelerated and pressurized. A diffuser chamber,
A scroll chamber that is formed outside the diffuser chamber and communicates with the interior of the diffuser chamber, and flows the air pressurized in the diffuser chamber to the outside;
The diffuser chamber is movably provided, and in a state where the diffuser chamber is moved to the diffuser chamber, a part of the communication portion between the diffuser chamber and the scroll chamber is partitioned, and the volume of the air flow path of the diffuser chamber is set to the impeller. A variable volume member that decreases toward the storage chamber side;
A variable displacement compressor housing. The variable volume member is
A first side surface that is formed in a curved shape in which a distance from the impeller is increased with respect to a rotation direction of the impeller when viewed in the axial direction of the impeller, and is disposed to face the impeller when protruding into the diffuser chamber;
The impeller is disposed outside the first side surface in the radial direction and on the outer periphery of the diffuser chamber, and the position of the downstream end in the rotation direction of the impeller is aligned with the position of the downstream end of the first side surface. A second side surface serving as an inner wall surface of the scroll chamber when protruding into the diffuser chamber;
A third side surface connecting the upstream end of the first side surface and the upstream end of the second side surface;
The variable displacement compressor housing according to claim 1, comprising:   In the axial direction of the impeller, the variable volume member is arranged such that the upstream end position of the first side surface in the rotational direction of the impeller is upstream from the upstream end position of the second side surface. The variable capacity compressor housing according to claim 2. The variable capacity compressor housing according to any one of claims 1 to 3,
Moving means for moving the variable volume member into the diffuser chamber;
Control means for operating the moving means based on information on the flow rate of air flowing into the impeller accommodating chamber, and for controlling the movement of the volume variable member;
A variable displacement compressor having