JP4483571B2 - Variable capacity turbocharger - Google Patents

Description

  The present invention relates to a variable displacement turbocharger, and more particularly to a variable displacement turbocharger capable of evaporating fuel adhering to a turbine.

  Currently, a variable capacity turbocharger (VG turbo) having a mechanism capable of more accurately controlling the amount of air to be supplied is manufactured mainly for diesel engines.

As one type of the variable capacity turbocharger, a VN turbo (variable nozzle turbo) is known in which the rotation of the turbine can be adjusted by variously changing the direction of the vanes. Regarding the turbine, for example, JP-A-11-229886 (Patent Document 1), JP-A 2004-169703 (Patent Document 2) and JP-A-7-25249 (Patent Document 3) are known.
JP 11-229886 A JP 2004-169703 A Japanese Utility Model Publication No. 7-25249

  In Patent Document 1, in a diesel engine equipped with a VN turbo, a seal structure is provided between a plate and a turbine housing to prevent invasion of gas containing a large amount of fuel and smoke due to insufficient vaporization of post-injection into the link chamber. Technology is disclosed.

  Patent Document 2 discloses a structure in which exhaust gas passes through a cavity when a movable wall moves.

  Patent Document 3 discloses a technique in which a link chamber of a turbo with a variable capacity nozzle is installed on the side opposite to a bearing.

  However, in any of the above-described techniques, fuel, gas, or the like enters the link chamber from a gap such as a pin for operating the nozzle due to a pressure difference between the vortex chamber and the link chamber. Then, there is a concern that the accumulated fuel and gas hinder the sliding of the unison ring and deteriorate the controllability.

  Among the conditions for post-injection, there are light load (low exhaust temperature) conditions, and there are cases where the fuel is insufficiently vaporized and the fuel condenses (liquefies) on the low temperature turbine housing surface. The turbocharger is designed to allow slight gas leakage, and because there is a pressure difference between the turbine vortex chamber and the link chamber, the fuel is transported between the nozzle ring and the turbine housing to the link chamber, Suits accumulate there.

  Accordingly, the present invention has been made to solve the above-described problems, and an object thereof is to provide a variable capacity turbocharger capable of preventing the movement of fuel to the link chamber.

Variable geometry turbocharger according to one aspect of the present invention includes a housing, to drive the vanes for adjusting the flow of the exhaust, e Bei a link mechanism provided in the housing, the housing, an exhaust turbine a turbine housing swirl chamber for supplying, provided a link chamber that houses the link mechanism, the housing, coupling holes are provided to connect the turbine housing swirl chamber and the link chamber, connecting holes, the turbine housing vortex It arrange | positions toward the downward direction of a chamber.
Preferably, the variable capacity turbocharger is mounted on a vehicle, and the connecting hole is disposed at the lowermost part.
Preferably, the housing is provided with an exhaust turbine chamber in which a turbine is accommodated, and further includes a shroud that partitions the exhaust turbine chamber and the link chamber, and the shroud is provided with scavenging holes that connect the exhaust turbine chamber and the link chamber. It has been.
A variable displacement turbocharger according to another aspect of the present invention includes a housing and a link mechanism provided in the housing for driving a vane for adjusting the flow of exhaust gas, and the housing supplies exhaust gas to the turbine. A turbine housing vortex chamber and a link chamber that houses the link mechanism are provided, and the housing is provided with a connecting hole that connects the turbine housing vortex chamber and the link chamber. It is mounted and the connecting hole is arranged at the bottom.
Preferably, the housing is provided with an exhaust turbine chamber in which a turbine is accommodated, and further includes a shroud that partitions the exhaust turbine chamber and the link chamber, and the shroud is provided with scavenging holes that connect the exhaust turbine chamber and the link chamber. It has been.
A variable displacement turbocharger according to yet another aspect of the present invention includes a housing and a link mechanism provided in the housing for driving a vane for adjusting the flow of exhaust gas. A turbine housing vortex chamber for supply and a link chamber for storing the link mechanism are provided. The housing is provided with a connecting hole for connecting the turbine housing vortex chamber and the link chamber, and the housing stores the turbine. The exhaust turbine chamber is provided with a shroud that partitions the exhaust turbine chamber and the link chamber, and the shroud is provided with scavenging holes that connect the exhaust turbine chamber and the link chamber.

  In the variable capacity turbocharger configured as described above, the pressure difference between the turbine housing vortex chamber and the link chamber can be reduced by the connection hole, and fuel can be prevented from moving to the link chamber. Further, since the high-temperature exhaust flows into the link chamber, the fuel in the link chamber can be evaporated.

If connection holes are disposed downwardly of the turbine housing swirl chamber, because the fuel entering the link chamber becomes a positional relationship in which flows down through the connecting hole towards the turbine-housing swirl chamber, the fuel in the link chamber staying It is possible to prevent the remaining state, and it is possible to prevent the generation of sludge in the link chamber.

When the variable displacement turbocharger is mounted on the vehicle and the connecting hole is disposed at the lowermost position, the connecting hole is located at the lowermost position on the vehicle, so that the deposited deposit in the link chamber is returned to the turbine housing vortex chamber. Can also serve as a discharge passage.

The housings, exhaust turbine chamber turbine is accommodated is provided with, further comprising a shroud that separates the exhaust turbine chamber and the link chamber, the shroud scavenging port is provided for connecting the exhaust turbine chamber and the link chamber In this case , the scavenging holes connecting the link chamber and the exhaust turbine chamber make it easy for hot exhaust gas introduced from the connection holes to enter the link chamber, raising the temperature of the link chamber and reducing the deposit in the link chamber. Can be burnt or stripped.

  According to the present invention, it is possible to provide a variable capacity turbocharger that can prevent fuel from moving to the link chamber.

  Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment 1)
1A and 1B are sectional views of a variable capacity turbocharger according to Embodiment 1 of the present invention. FIG. 1A is an overall view, and FIG. 1B is a sectional view of scavenging holes. Referring to FIG. 1, a variable capacity turbocharger 1 according to an embodiment of the present invention is a variable nozzle turbocharger, and includes a housing 201, a shaft 7 rotatably accommodated in the housing 201, and a shaft 7. And a compressor wheel 34 and a turbine wheel assembly 22 attached to the turbine wheel assembly 22.

  The housing 201 is divided into a compressor housing 2, a center housing 36 and a turbine housing 48, and the compressor housing 2 and the turbine housing 48 are attached to both sides of the center housing 36. In the compressor housing 2, it is set as the shape which can take in air from a center part, and can discharge | release it outside. Specifically, air is introduced into the central portion of the compressor housing 2, and the air is accelerated and compressed outward by the rotating compressor wheel 34, and the compressed air is guided to an intake manifold (not shown).

  A compressor wheel 34 is accommodated in the compressor housing 2. The compressor wheel 34 is fixed to a shaft 7 as a turbine shaft and rotates together with the shaft 7. The compressor wheel 34 is fixed to the shaft 7 by a lock nut 35. The compressor wheel 34 is provided with a plurality of blades. When the compressor wheel 34 rotates, the blades accelerate and compress air by centrifugal force.

  A thrust spacer 25 is disposed adjacent to the compressor wheel 34. The thrust spacer 25 is shaped to surround the shaft 7. A back plate 32 is provided on the back surface of the compressor housing 2. The back plate 32 is attached to the compressor housing 2 by bolts 9 and has a shape in which the thrust spacer 25 is fitted. An O-ring 8 is arranged between the back plate 32 and the compressor housing 2 to improve the sealing performance. A piston ring 31 is fitted on the outer periphery of the thrust spacer 25.

  The center housing 36 is provided at the center of the variable capacity turbocharger 1. The back plate 32 is fixed to the center housing 36 by bolts 33. A seal ring 27 is provided between the back plate 32 and the center housing 36 for improving the sealing performance.

  A thrust bearing 26 is disposed so as to contact the center housing 36. The thrust bearing 26 is a bearing for receiving a load in the thrust direction of the shaft 7 and is lubricated by oil or the like. A thrust collar 28 is disposed on the inner peripheral side of the thrust bearing 26. The thrust collar 28 is provided so as to be in contact with the thrust spacer 25 and is also in contact with the stepped portion of the shaft 7.

  The center housing 36 is provided with pins 49. The center housing 36 is provided with a bearing 24 that holds the rotation of the shaft 7. The bearing 24 holds the load in the radial direction of the shaft 7.

  A retainer ring 30 is fitted into the bearing 24, and the retainer ring 30 is also engaged with the center housing 36.

  A link mechanism 202 is disposed in the center housing 36 and the turbine housing 48. The link mechanism 202 includes a unison ring 45 housed in the link chamber 6, an arm 44 that is located on the inner periphery of the unison ring 45 and contacts the unison ring 45, and a nozzle ring 43 that is provided adjacent to the turbine housing 48. A main arm 37 is connected to the pin 39 and drives a plurality of arms 44.

  The link mechanism 202 is a mechanism for adjusting the angle of the plurality of vanes 42. When the pin 40 is rotated by a predetermined angle, the rotation is transmitted to the vane 42, and the vane 42 is rotated. Has been. Specifically, the pin 40 is connected to a crank external 41, and the crank external 41 is rotatable around a pin 39. A bush 38 is provided on the outer periphery of the pin 49, and the bush 38 is interposed between the pin 39 and the center housing 36.

  The pin 39 is connected to the main arm 37, and this rotation is transmitted to the main arm 37 when the pin 39 rotates. An inner end portion of the main arm 37 is fixed to the pin 39, and an outer end portion is engaged with the unison ring 45. Therefore, the main arm 37 rotates around the pin 39 and this rotation is transmitted to the unison ring 45. The arm 44 is fitted on the inner peripheral surface of the unison ring. When the unison ring 45 is rotated, this rotation is transmitted to the arm 44. The arm 44 can rotate around the pin 21, and the rotation of the arm 44 is transmitted to the pin 21. Since the pin 21 is connected to the vane 42, the vane 42 rotates together with the pin 21 and the arm 44.

  The nozzle ring 43 is fixed to the turbine housing 48 by a cap screw 47. A vane spacer 46 is provided on the outer periphery of the cap screw 47. A turbine wheel assembly 22 is attached to the end of the shaft 7. The turbine wheel assembly 22 is located in the exhaust turbine chamber 148.

  A disc shroud 23 is provided between the turbine wheel assembly 22 and the link chamber 6, and the disc shroud 23 plays a role of improving the airtightness of the exhaust turbine chamber 148. Moreover, in order to improve airtightness, the piston ring 29 is fitted on the outer periphery of the shaft 7. The disc shroud 23 is provided with a plurality of scavenging holes 4. The scavenging holes 4 serve to connect the link chamber 6 and the exhaust turbine chamber 148.

  A turbine housing vortex chamber 5 is provided on the outer periphery of the turbine housing 48, and exhaust gas is supplied from the turbine housing vortex chamber 5. The exhaust is exhausted from the exhaust turbine chamber 148 by rotating the turbine wheel assembly 22. The turbine housing 48 is provided with a connection hole 3 for connecting the turbine housing vortex chamber 5 and the link chamber 6. Due to the connection hole 3, the pressures in the turbine housing vortex chamber 5 and the link chamber 6 are substantially the same. The turbine housing 48 is attached to the center housing 36 by bolts 10.

  That is, the variable displacement turbocharger 1 drives a turbine housing 48 that is a part of a housing 201 for supplying exhaust to the turbine wheel assembly 22 and a vane 42 for adjusting the flow of exhaust. And a link mechanism 202 provided in the center housing 36.

  The turbine housing 48 and the center housing 36 include a turbine housing vortex chamber 5 for supplying exhaust gas to the turbine wheel assembly 22 and a link chamber 6 in which the link mechanism 202 is accommodated. The turbine housing 48 is provided with a connecting hole 3 that connects the turbine housing vortex chamber 5 and the link chamber 6. The turbine housing 48 is provided with an exhaust turbine chamber 148 in which the turbine wheel assembly 22 is housed. The exhaust turbine chamber 148 and the link chamber 6 are partitioned by a disk shroud 23. A scavenging hole 4 that connects the turbine chamber 148 and the link chamber 6 is provided.

  FIG. 2 is a cross-sectional view taken along the line II-II in FIG. Referring to FIG. 2, a disc-shaped nozzle ring 43 is fitted on the inner periphery of an annular unison ring 45. The nozzle ring 43 is fixed to the turbine housing by a cap screw 47, and a vane spacer 46 is provided on the outer periphery of the cap screw 47.

  The unison ring 45 is slidable with respect to the nozzle ring 43. The main arm 37 and the arm 44 are fitted into the outer peripheral recess of the unison ring 45. Each of the arms 44 is connected to a vane 42, and the vane 42 can be rotated to a position indicated by a dotted line. The flow rate and flow velocity of the exhaust from the turbine vortex chamber to the exhaust turbine chamber can be adjusted by the rotation angle of the vane 42.

  3 is a cross-sectional view taken along line III-III in FIG. Referring to FIG. 3, main arm 37 and arm 44 are fitted in the inner circumferential recess of unison ring 45. A pin 39 is provided so as to penetrate the nozzle ring 43, and the pin 39 is connected to the main arm 37. When the main arm 37 rotates around the pin 39, the unison ring 45 engaged with the main arm 37 rotates. With this rotation, the arm 44 also rotates about the pin 21. The pin 21 rotates, the rotation is transmitted to the vane 42 in FIG. 2, and the vane 42 rotates.

  4 is a cross-sectional view taken along line IV-IV in FIG. Referring to FIG. 4, a pin 52 is inserted into the nozzle ring 43, and a roller 51 is fitted over the pin 52. The roller 51 guides the inner peripheral surface of the unison ring 45. As a result, the unison ring 45 is held by the roller 51 and can be rotated in a predetermined direction.

  FIG. 5 is a block diagram showing a control mechanism of the variable capacity turbocharger according to the first embodiment of the present invention. Referring to FIG. 5, a variable displacement turbocharger (variable nozzle type turbocharger) 1 is controlled by a variable nozzle controller 200 and an engine control computer 300.

  Specifically, the engine control computer 300 determines the required variable nozzle opening based on the ignition switch, the accelerator opening, the engine speed, the atmospheric temperature, the atmospheric pressure, the supercharging pressure, the cooling water temperature, and the like. This determined data is transmitted to the variable nozzle controller 200. The variable nozzle controller 200 gives the drive output of the DC motor to the variable displacement turbocharger (variable nozzle type turbocharger) 1 based on the above data, and the opening degree of the nozzle is determined. It is determined.

  Information about the opening of the nozzle is fed back to the variable nozzle controller 200, and a motor status signal is sent from the variable nozzle controller 200 to the engine control computer 300.

  In the variable displacement turbocharger 1, the engine speed is adjusted by opening and closing a vane 42 as a variable nozzle provided on the outer periphery of the turbine wheel assembly by a motor and adjusting the flow velocity and pressure of exhaust gas input to the turbocharger. In addition, the balance between the back pressure and the supercharging pressure can be optimally controlled with respect to the load.

  The variable displacement turbocharger 1 includes a nozzle (vane 42), a DC motor (not shown), a link mechanism 202 that connects the vane 42 and the DC motor, and an opening sensor (not shown). The driving force of the DC motor is transmitted in the order of the pins 40 and 39, the main arm 37, the unison ring 45, the arm 44 and the pin 21. Various methods of controlling the vane 42 are conceivable. For example, in the low and medium speed range of the engine, the vane 42 is squeezed to increase the flow rate of the exhaust gas, thereby improving the rising characteristic of the supercharging pressure and the supercharging pressure. It is possible to reduce the graphite and improve the torque. On the other hand, in the high engine speed range, the passage of the vane 42 is opened to lower the exhaust pressure, thereby improving the fuel consumption and output and preventing the turbine wheel assembly 22 from over-rotating. When the EGR (exhaust gas recirculation) is operated, the opening degree of the vane 42 is adjusted in order to stabilize the EGR control.

  The variable displacement turbocharger 1 according to the first embodiment is intended to prevent fuel from moving through the gap between the turbine housing 48 and the nozzle ring 43. This fuel is injected into the exhaust gas on the upstream side of the turbine housing vortex chamber 5 and used to burn particulate matter accumulated in the DPNR provided on the downstream side of the exhaust turbine chamber 148. By providing the connection hole 3 connecting the turbine housing vortex chamber 5 and the link chamber 6 at the lower part of the turbine housing 48, the pressure difference between the turbine housing vortex chamber 5 and the link chamber 6 is reduced. This connection hole 3 may be one place or two or more places.

  The position and size of the connection hole 3 are determined with reference to the area of the gap between the nozzle ring 43 and the turbine housing 48. The connecting hole 3 is provided on the surface where fuel is not attached as much as possible. A scavenging hole 4 is provided in the disk shroud 23 (partition plate on the back of the turbine blade) to create a gas flow from the turbine housing vortex chamber 5 toward the link chamber 6 toward the turbine back side. The number of scavenging holes 4 is, for example, three, and is preferably provided with an interval of 120 degrees. Due to the gas flow through the scavenging holes 4, the temperature of the link chamber 6 can be further increased.

  Further, the object of the present invention is to burn or peel the deposit in the link chamber 6. For this purpose, a connecting hole 3 for connecting the link chamber 6 and the turbine housing vortex chamber 5 is provided. It is preferable to provide two or more connecting holes 3 because exhaust gas is less likely to stagnate. As described above, in the variable capacity turbocharger 1 according to the present invention, since the connecting hole 3 and the scavenging hole 4 are provided, the pressure difference between the turbine housing vortex chamber 5 and the link chamber 6 can be reduced as much as possible. It is possible to prevent the fuel from moving to the link chamber 6. Even if the fuel is moved to the link chamber 6, the high-temperature exhaust gas flows into the link chamber 6 through the connection hole 3 and the scavenging hole 4, so that the fuel in the link chamber 6 can be evaporated.

  Note that the scavenging holes 4 are not necessarily provided, and only the connection holes 3 may be provided without providing the scavenging holes 4.

(Embodiment 2)
FIG. 6 is a sectional view of a variable capacity turbocharger according to the second embodiment of the present invention. Referring to FIG. 6, in variable displacement turbocharger 1 according to the second embodiment of the present invention, connection hole 3 is arranged toward the lower portion of the turbine vortex chamber. That is, the connecting hole 3 extends toward the lower part of the turbine housing vortex chamber 5. The variable capacity turbocharger 1 is mounted on a vehicle, and the connection hole 3 is provided at the bottom, that is, the position of the variable capacity turbocharger 1 closest to the ground.

  In the variable displacement turbocharger 1 according to the second embodiment configured as described above, since the fuel that has entered the link chamber 6 flows into the turbine housing vortex chamber 5 through the connection hole 3, the link is established. It is possible to prevent the fuel from being accumulated in the chamber 6 and to prevent the generation of sludge in the link chamber 6. Further, since the connecting hole 3 is located at the lowest part on the vehicle, it can also serve as a discharge middle path for returning the peeled deposit in the link chamber 6 to the turbine housing vortex chamber 5.

(Embodiment 3)
FIG. 7 is a plan view of a variable capacity turbocharger according to the third embodiment of the present invention. Referring to FIG. 7, in variable displacement turbocharger 1 according to the third embodiment of the present invention, discharge hole 149 is provided for discharging fuel accumulated in the lower portion of turbine housing vortex chamber 5 to the turbine inlet. ing. Thereby, fuel can be prevented from flowing from the turbine housing vortex chamber 5 into the link chamber. The discharge hole 149 is provided at an angle so as not to receive the dynamic pressure of the gas flow at the turbine inlet.

  Although the embodiment of the present invention has been described above, the embodiment shown here can be variously modified. First, the variable capacity turbocharger 1 of the present invention is mainly mounted with a diesel engine. However, the present invention is not limited to this, and a variable capacity turbocharger according to the present invention is provided in a gasoline engine or a rotary engine. Also good. Furthermore, the present invention may be applied to a hybrid vehicle using a diesel engine or a gasoline engine.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention can be used in the field of variable capacity turbochargers in which the flow rate of air supplied to the turbine can be changed as appropriate.

It is sectional drawing of the variable capacity | capacitance type turbocharger according to Embodiment 1 of this invention, (A) is a general view, (B) is sectional drawing of a scavenging hole. It is sectional drawing along the II-II line | wire in FIG. It is sectional drawing along the III-III line in FIG. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. It is a block diagram which shows the control mechanism of the variable capacity | capacitance type turbocharger according to Embodiment 1 of this invention. It is sectional drawing of the variable capacity | capacitance type turbocharger according to Embodiment 2 of this invention. It is a top view of the variable capacity | capacitance type turbocharger according to Embodiment 3 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Variable capacity type turbocharger, 2 Compressor housing, 3 Connecting hole, 4 Scavenging hole, 5 Turbine housing vortex chamber, 6 Link chamber, 36 Center housing, 201 Housing, 202 Link mechanism

Claims (6)

A housing;
A link mechanism provided in the housing for driving a vane for adjusting the flow of exhaust;
The housing is provided with a turbine housing vortex chamber for supplying exhaust to the turbine, and a link chamber for housing the link mechanism,
The housing is provided with a connecting hole that connects the turbine housing vortex chamber and the link chamber ,
The connection hole is a variable capacity turbocharger disposed toward the lower side of the turbine housing vortex chamber . The variable capacity turbocharger according to claim 1, wherein the variable capacity turbocharger is mounted on a vehicle, and the connection hole is disposed at a lowermost part . The housing is provided with an exhaust turbine chamber in which a turbine is accommodated. The housing further includes a shroud that partitions the exhaust turbine chamber and the link chamber, and the shroud includes a sweep that connects the exhaust turbine chamber and the link chamber. The variable capacity turbocharger according to claim 1 or 2 , wherein pores are provided .   A housing;
  A link mechanism provided in the housing for driving a vane for adjusting the flow of exhaust;
  The housing is provided with a turbine housing vortex chamber for supplying exhaust to the turbine, and a link chamber for housing the link mechanism,
  The housing is provided with a connecting hole that connects the turbine housing vortex chamber and the link chamber,
  The variable capacity turbocharger is mounted on a vehicle, and the connecting hole is disposed at the bottom.   The housing is provided with an exhaust turbine chamber in which a turbine is accommodated. The housing further includes a shroud that partitions the exhaust turbine chamber and the link chamber, and the shroud includes a sweep that connects the exhaust turbine chamber and the link chamber. The variable capacity turbocharger according to claim 4, wherein pores are provided.   A housing;
  A link mechanism provided in the housing for driving a vane for adjusting the flow of exhaust;
  The housing is provided with a turbine housing vortex chamber for supplying exhaust to the turbine, and a link chamber for housing the link mechanism,
  The housing is provided with a connecting hole that connects the turbine housing vortex chamber and the link chamber,
  The housing is provided with an exhaust turbine chamber in which a turbine is accommodated. The housing further includes a shroud that partitions the exhaust turbine chamber and the link chamber, and the shroud includes a sweep that connects the exhaust turbine chamber and the link chamber. Variable capacity turbocharger with pores.

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