JP2008215097A - Exhaust fuel adding device of internal combustion engine with turbocharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To atomize and disperse well the fuel added to exhaust gas and uniformly mix it with the exhaust gas, and to suppress failure in operation of a variable nozzle mechanism of a turbocharger which is caused by the added fuel. <P>SOLUTION: The exhaust fuel adding device is equipped with: a turbine wheel having a hub connected to a rotor shaft and a plurality of turbine blades provided on the surface of the hub, for receiving the flow of exhaust gas by the turbine blades and rotating; a turbine shroud covering the periphery of the turbine wheel on the outer part of the turbine wheel; a fuel passage provided inside the hub and in which fuel flows; a fuel supply means for supplying fuel to the fuel passage; an opening part provided at a position opposing an inner wall face of the turbine shroud on an edge or a surface of at least two turbine blades positioned in point symmetry with respect to a rotary shaft of the turbine wheel out of the turbine blades; and a fuel adding passage provided inside the turbine blades provided with the opening part for connecting the opening part to the fuel passage. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an exhaust fuel addition device for an internal combustion engine with a turbocharger.

  As an exhaust purification device, there is an internal combustion engine provided with an exhaust purification catalyst for detoxifying harmful components in exhaust gas in the middle of an exhaust passage. In an internal combustion engine provided with an exhaust purification catalyst, exhaust fuel addition for adding a reducing agent such as fuel to exhaust gas may be performed for the purpose of maintaining or regenerating the catalytic function of the exhaust purification catalyst (for example, Patent Document 1). See). There is also an internal combustion engine provided with a turbocharger having a turbine arranged in an exhaust passage as a supercharger.

  When adding fuel into the exhaust gas in an internal combustion engine equipped with a turbocharger, if the fuel is added into the exhaust gas upstream of the turbine, most of the added fuel will not vaporize sufficiently to reach the turbine, It circulates in the turbine scroll together with the exhaust gas in a liquid state. Therefore, in particular, in the case of a variable displacement turbocharger having a nozzle vane or a variable nozzle mechanism that opens and closes the nozzle vane in the turbine scroll, fuel adheres to the movable part of the variable nozzle mechanism, and the movable part is fixed. There was a possibility of bringing about.

On the other hand, if fuel is added into the exhaust downstream from the turbine, the distance between the position where the fuel is added and the exhaust purification catalyst cannot be sufficiently secured, and it becomes difficult to sufficiently obtain the stirring effect by the turbine. For this reason, the added fuel does not atomize and disperse well and flows into the exhaust purification catalyst in a state where it is not sufficiently uniformly mixed with the exhaust gas. It was.
JP 2006-77691 A JP 2003-286905 A JP 2003-41929 A

  The present invention has been made in view of such problems, and in an internal combustion engine with a turbocharger, the fuel added to the exhaust is well atomized and dispersed to be sufficiently uniformly mixed with the exhaust, and the turbocharger. An object of the present invention is to provide a technique for suppressing the occurrence of problems in the operation of the variable nozzle mechanism due to the added fuel when the turbine of this type includes a variable nozzle mechanism.

In order to achieve the above object, an exhaust fuel addition device for an internal combustion engine with a turbocharger according to the present invention is arranged in the middle of an exhaust passage of the internal combustion engine, and has a hub connected to a rotor shaft and a plurality of devices provided on the surface of the hub. A turbine wheel that is rotatably supported by the rotor shaft and rotates around the rotor shaft by receiving the flow of exhaust gas flowing through the exhaust passage by the turbine blade, and the turbine A turbine shroud provided so as to cover the periphery of the turbine wheel outside the wheel; a fuel passage provided inside the hub; a fuel supply means for supplying fuel to the fuel passage; Of the turbine blades of the turbine wheel An opening provided at a position facing an inner wall surface of the turbine shroud at an edge or surface of at least two turbine blades provided at a position, and provided inside each turbine blade provided with the opening. And a fuel addition passage having one end connected to the fuel passage inside the hub and the other end connected to each of the openings.

  According to this configuration, the fuel supplied to the fuel passage by the fuel supply means is added to the exhaust flow for rotating the turbine wheel from the edge or surface of the turbine blade through the fuel addition passage and the opening. . Since the fuel added from the opening is vigorously stirred by the rotating turbine blade, fuel atomization and vaporization are promoted. Thereby, also in the exhaust passage immediately downstream of the turbine, the added fuel is sufficiently mixed with the exhaust. Therefore, when the exhaust fuel addition device of the present invention is used, even when the exhaust purification catalyst is disposed immediately downstream of the turbine, for example, the added fuel in a sufficiently uniformly mixed state in the exhaust is caused to flow into the exhaust purification catalyst. Therefore, it is possible to suitably regenerate the catalyst function by adding exhaust fuel.

  In addition, according to the above configuration, when the fuel is added, the turbine blade is cooled by temporarily adhering the fuel to the turbine blade and vaporizing it, so that thermal fatigue of the turbine blade can be suppressed. There is also an effect. Further, according to the above configuration, the turbine blade provided with the fuel addition passage and the opening (hereinafter sometimes collectively referred to as a fuel addition system) is rotationally symmetric with respect to the rotation axis of the turbine wheel. It is possible to suppress the occurrence of imbalance in the rotational movement of the turbine wheel due to the provision of the fuel addition system and the addition of fuel from the turbine blade.

  Here, the positions where the openings on the edges or surfaces of the turbine blades where the fuel addition system is provided are substantially equal to each other, and the openings may have a point-symmetric positional relationship with respect to the rotation axis. Furthermore, each fuel addition passage may be provided inside each turbine blade so as to have a point-symmetric positional relationship with respect to the rotation axis. In this way, it is further ensured that the rotational symmetry of the turbine wheel is impaired due to the provision of a fuel addition system in a part of the plurality of turbine blades or the addition of fuel from the fuel addition system. Can be suppressed.

  In the above configuration, instead of providing an opening at the edge or surface of the turbine blade, at least two positions on the surface of the hub where the turbine blade is not provided are positioned symmetrically with respect to the rotation axis of the turbine wheel. An opening may be provided.

  Also in this configuration, the fuel supplied to the fuel passage by the fuel supply means is added from the hub in the portion where the turbine blade is not provided through the fuel addition passage and the opening. The fuel added from the opening is vigorously stirred by the rotating turbine blades, and fuel atomization and vaporization are promoted. As a result, even in the exhaust passage immediately downstream of the turbocharger, the added fuel is sufficiently mixed with the exhaust.

  Also in this configuration, when the fuel is added, the fuel temporarily adheres to the turbine blade and vaporizes, whereby the turbine blade cooling effect can be obtained. In addition, since the opening provided in the hub is rotationally symmetric with respect to the rotation axis of the turbine wheel, the rotational movement of the turbine wheel is unbalanced due to the provision of the opening in the hub or the addition of fuel from the hub. Can be prevented from occurring.

  Further, each fuel addition passage may be provided inside the hub so as to have a point-symmetric positional relationship with respect to the rotation axis. In this way, it is further ensured that the rotational symmetry of the turbine wheel is impaired due to the provision of a fuel addition system such as a fuel addition passage and an opening in the hub or the addition of fuel from the opening. Can be suppressed.

In each configuration described above, as the fuel supply means, for example, a passage through which fuel can flow is provided in the rotor shaft and the compressor wheel connected to the end of the rotor shaft opposite to the turbine wheel, It can be realized by connecting one end of the passage to a fuel passage in the turbine wheel and connecting the other end to a fuel supply device such as a fuel tank or a fuel pump installed outside the turbocharger.

  The turbocharger which concerns on this invention is provided in the inside of the exhaust flow path formed along the circumferential direction of the said turbine wheel outside the said turbine wheel, The variable which has a nozzle vane which changes the flow path area of the said exhaust flow path In the case of a variable capacity turbocharger equipped with a nozzle mechanism, the opening in each of the above-described configurations is positioned at a position where the fuel added from each opening through the fuel addition passage does not collide with the nozzle vane. It may be provided.

  The position where the added fuel does not collide with the nozzle vane is, for example, when the opening is provided at the edge of the turbine blade, the straight line connecting the rotating shaft of the turbine wheel and each opening is the exhaust flow path outside the turbine wheel. It is a position that does not enter the formed part. Or it can also be set as the position where the straight line which connects the rotating shaft of a turbine wheel and each opening part cross | intersects the inner wall surface of the turbine shroud which covers the part in which the exhaust flow path is not formed in the exterior of a turbine wheel. Moreover, when providing an opening part in the surface of a turbine blade, or a hub, it can also be set as the position facing the inner wall face of the turbine shroud which covers the part in which the exhaust flow path is not formed in the exterior of a turbine wheel.

  According to this configuration, since the added fuel is suppressed from adhering to the variable nozzle mechanism including the nozzle vane, it is possible to suppress the occurrence of problems in the operation of the variable nozzle mechanism due to the added fuel.

  Although the configuration in which fuel is added from the hub of the turbine wheel or the turbine blade has been described above, the present invention may be configured to add fuel from the inner wall surface of the turbine shroud toward the turbine blade. That is, the present invention includes a hub that is disposed in the middle of an exhaust passage of an internal combustion engine and is connected to a rotor shaft, and a plurality of turbine blades provided on the surface of the hub, and is rotatably supported by the rotor shaft. And a turbine wheel that rotates around the rotor shaft by receiving the flow of exhaust gas flowing through the exhaust passage on the turbine blade, and is formed outside the turbine wheel along a circumferential direction of the turbine wheel. A variable nozzle mechanism provided inside the exhaust passage and having a nozzle vane for changing the passage area of the exhaust passage, and a turbine shroud covering a portion outside the turbine wheel where the exhaust passage is not formed. An opening provided at a position facing the turbine blade on the wall surface; An exhaust fuel addition device for an internal combustion engine with a turbocharger, comprising: a fuel addition passage connected to the opening and through which fuel flows; and a fuel supply means for supplying fuel to the fuel addition passage. Also good.

  According to this structure, the fuel added from the opening provided in the inner wall surface of the turbine shroud is vigorously stirred by the rotating turbine blade, and atomization and vaporization are promoted. Thereby, also in the exhaust passage immediately downstream of the turbine, the added fuel is sufficiently mixed with the exhaust.

  Moreover, since the opening is provided at a position facing the turbine blade on the inner wall surface of the turbine shroud, the added fuel is prevented from adhering to the variable nozzle mechanism. It is possible to suppress the occurrence of defects.

  Also in this configuration, when the fuel is added, the fuel temporarily adheres to the turbine blade and vaporizes, whereby the turbine blade cooling effect can be obtained.

  In addition, said each structure can be employ | adopted combining as much as possible.

  According to the exhaust fuel addition device of the present invention, in an internal combustion engine with a turbocharger, the added fuel is atomized and dispersed well even immediately after the turbine, while suppressing problems in the operation of the variable nozzle mechanism of the exhaust turbine, It is possible to obtain a state of being almost uniformly mixed with the exhaust. Therefore, even when the exhaust purification catalyst is provided immediately downstream of the turbine, it is possible to satisfactorily maintain the catalytic function of the exhaust purification catalyst by adding the exhaust fuel.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. The dimensions, materials, shapes, relative arrangements, and the like of the components described in the present embodiment are not intended to limit the technical scope of the invention to those unless otherwise specified.

  FIG. 1 is a conceptual diagram schematically showing a schematic configuration of an internal combustion engine to which an exhaust fuel addition device for an internal combustion engine with a turbocharger according to the present embodiment is applied, and its intake system and exhaust system.

  An internal combustion engine 1 shown in FIG. 1 is a water-cooled four-cycle diesel engine having four cylinders 2. The internal combustion engine 1 includes a fuel injection valve (not shown) that directly injects fuel into the cylinder 2.

  Each cylinder 2 of the internal combustion engine 1 communicates with the intake passage 3 via an intake manifold 13. The intake passage 3 is provided with an intercooler 8 for cooling the intake air. The intake passage 3 upstream of the intercooler 8 is provided with a compressor 6 of a turbocharger 5 that operates using exhaust energy as a drive source. An air cleaner 9 is provided in the intake passage 3 upstream of the compressor 6. The air that has passed through the air cleaner 9 and entered the intake passage 3 is compressed by the compressor 6, cooled by the intercooler 8, and flows into the cylinder 2. The air flowing into the cylinder 2 burns in the cylinder 2 together with the fuel injected from the fuel injection valve provided in the cylinder 2.

  Each cylinder 2 of the internal combustion engine 1 communicates with the exhaust passage 4 via an exhaust manifold 14. A turbine 7 of a turbocharger 5 is provided in the exhaust passage 4. An exhaust purification device 10 is provided in the exhaust passage 4 downstream of the turbine 7. The exhaust purification device 10 has a NOx storage reduction catalyst having oxidation ability and NOx storage ability, and a particulate filter having oxidation ability and PM trapping ability. The exhaust purification device 10 may be a particulate filter or the like on which an NOx storage reduction catalyst is supported. The exhaust discharged from the cylinder 2 passes through the turbine 7 to drive the compressor 6, passes through the exhaust purification device 10, is purified, and is released to the atmosphere.

  Here, the turbocharger 5 in the present embodiment will be described. FIG. 2 shows a cross-sectional view of a surface including the rotation axis of the turbocharger 5.

In FIG. 2, the turbine wheel 15 of the turbine 7 is connected to the compressor impeller 16 of the compressor 6 and the rotor shaft 18. The rotor shaft 18 is rotatably supported by a bearing 34 and a bearing 36. The turbine wheel 15 has a hub 20 and a plurality of turbine blades 22 provided on the hub 20. The turbine wheel 15 receives an exhaust flow from the turbine blade 22 and rotates in the turbine shroud 24 with the rotor shaft 18 as a rotation axis. The compressor impeller 16 includes a hub 26 and a plurality of vanes 28 provided on the hub 26.
As the turbine wheel 15 rotates, the rotor shaft 18 rotates in the compressor shroud 30 with the rotor shaft 18 as a rotation axis.

  The turbine 7 has an inlet scroll chamber 42 connected to the exhaust passage 4 upstream from the turbine 7, an outlet passage 44 connected to the exhaust passage 4 downstream from the turbine 7, and an inlet by the turbine shroud 24 outside the turbine wheel 15. A turbine blade chamber 46 formed in a funnel shape from the scroll chamber 42 to the outlet passage 44. Exhaust gas discharged from the internal combustion engine 1 into the exhaust passage 4 flows into the turbine 7 from the inlet scroll chamber 42, circulates in the turbine blade chamber 46 and rotationally drives the turbine wheel 15, and then passes through the exhaust passage 4 from the outlet passage 44. To leak.

  At the boundary between the inlet scroll chamber 42 and the turbine blade chamber 46, a plurality of nozzle vanes 48 are provided on the circumference around the rotor shaft 18 outside the turbine wheel 15 in an annular blade row. . Each nozzle vane 48 is pivotally supported by a shaft 50 at the center thereof, and each shaft 50 is rotationally driven by a nozzle vane driving device 52. By rotating the nozzle vanes 48 in unison with each other by the nozzle vane driving device 52, the opening degree of the nozzle openings formed between the adjacent nozzle vanes 48 is variably adjusted, and the rotational speed of the turbine wheel 15 is adjusted. The

  The compressor 6 includes an inlet passage 54 connected to the intake passage 3 upstream of the compressor 6, an outlet diffuser 56 connected to the intake passage 3 downstream of the compressor 6, and an inlet passage by the compressor shroud 30 outside the compressor impeller 16. And a compressor vane chamber 58 formed in a funnel shape from 54 to the outlet diffuser 56. The air flowing into the intake passage 3 through the air cleaner 9 flows into the compressor 6 from the inlet passage 54, flows through the compressor vane chamber 58 and is compressed by the rotation of the compressor impeller 16, and then enters the intake passage 3 from the outlet diffuser 56. leak.

  As described above, the turbocharger 5 of the present embodiment is a variable capacity turbocharger having a known variable nozzle mechanism.

  Next, the exhaust emission control device 10 in the present embodiment will be described.

  The NOx storage reduction catalyst of the exhaust purification apparatus 10 oxidizes nitrogen oxide (NOx) in the exhaust and temporarily stores it in the form of nitrate when the oxygen concentration of the inflowing exhaust gas is high. Further, when the oxygen concentration of the exhaust gas flowing in decreases, NOx stored in the presence of a reducing agent such as unburned hydrocarbon (HC) or carbon monoxide (CO) is released and reduced. The particulate filter collects particulate matter (PM) in the exhaust. The PM collected and deposited on the particulate filter is oxidized by the oxidizing action of the oxidation catalyst supported on the particulate filter, and is removed from the particulate filter.

  There is a limit to the amount of NOx that can be stored in the NOx storage reduction catalyst. The NOx stored in the NOx storage reduction catalyst is periodically released and reduced to regenerate the catalytic function of the NOx storage reduction catalyst. It is necessary to let Further, there is a limit to the amount of PM that can be deposited on the particulate filter, and it is necessary to periodically oxidize and remove the PM deposited on the particulate filter to regenerate the PM collection function of the particulate filter.

When a diesel engine is provided as the internal combustion engine 1 as in this embodiment, the exhaust gas upstream of the exhaust gas purification device 10 is regenerated in order to regenerate the catalytic function of the NOx storage reduction catalyst and the PM trapping function of the particulate filter. It is effective to add fuel as a reducing agent in the exhaust gas in the passage 4. That is, when fuel is added to the exhaust gas, the fuel is thermally decomposed in high-temperature exhaust gas and a large amount of HC is generated. This HC reacts with oxygen in the NOx storage reduction catalyst as a reducing agent, and the storage reduction type The oxygen concentration in the exhaust gas flowing into the NOx catalyst decreases. Thereby, the ambient atmosphere of the NOx storage reduction catalyst becomes a reducing atmosphere, and the release and reduction reaction of NOx stored in the NOx storage reduction catalyst is promoted. In addition, the catalyst bed temperature of the oxidation catalyst rises due to the reaction heat when this HC undergoes an oxidation reaction in the oxidation catalyst in the particulate filter, and the oxidation of PM deposited on the particulate filter by the action of the oxidation catalyst activated thereby. Is promoted and efficiently removed.

  By the way, in the internal combustion engine 1 having the turbocharger 5 as in this embodiment, when the exhaust fuel addition for regenerating the exhaust purification function of the exhaust purification device 10 is performed as described above, the exhaust passage upstream of the turbine 7 is performed. When the fuel is added at 4, much of the added fuel flows into the inlet scroll chamber 42 of the turbine 7 without being sufficiently vaporized before reaching the turbine 7. For this reason, there is a possibility that the fuel adheres to the movable part of the variable nozzle mechanism including the nozzle vane 42, the shaft 50, and the like, thereby causing problems such as fixing the movable part.

  Further, when fuel is added in the exhaust passage 4 downstream from the turbine 7, a sufficient distance between the position where the fuel is added and the exhaust purification device 10 cannot be secured, and due to the rotation of the turbine wheel 15 of the turbine 7. A sufficient stirring effect cannot be obtained. Therefore, the added fuel flows into the exhaust purification device 10 without being sufficiently atomized and dispersed, and it is difficult to suitably regenerate the exhaust purification function of the NOx storage reduction catalyst or the particulate filter by adding the fuel. There was a risk of becoming.

  On the other hand, the turbocharger 5 in the present embodiment has the following characteristic points in addition to the basic structure described above. That is, as shown in FIG. 2, a fuel passage 60 is provided in the hub 26 of the compressor impeller 16, the rotor shaft 18, and the hub 20 of the turbine wheel 15 so as to penetrate them. The end of the fuel passage 60 on the hub 26 side is connected to a fuel supply passage 66 provided outside the compressor impeller 16, and a fuel supply device 68 installed outside the turbocharger 5 via the fuel supply passage 66. Communicate. The fuel supply device 68 includes a tank that stores fuel, a pump that supplies fuel to the fuel supply passage 66, and the like. The fuel supply device 68 may be configured to share a part thereof with a fuel injection system that injects fuel into the cylinder 2. In the present embodiment, the fuel supply passage 66 and the fuel supply device 68 correspond to the fuel supply means in the present invention.

  Among the plurality of turbine blades 22 of the turbine wheel 15, at the edges (blade tips) of at least two turbine blades 22 provided at positions that are point-symmetric with respect to the rotation axis of the turbine wheel 15 (that is, the rotor shaft 18). An opening 62 is provided at a position facing the inner wall surface of the turbine shroud 24 (in other words, the inner wall surface of the turbine blade chamber 46). Here, the turbine blades having a point-symmetrical positional relationship with respect to the rotation axis of the turbine wheel 15 mean N turbine blades provided at an angle of 360 / N degrees at an angle around the rotation axis. To do. Here, N is an integer not less than 2 and not more than the total number of turbine blades 22 provided on the turbine wheel 15. Here, it is preferable that the positions where the openings 62 are provided at the edges of the turbine blades 22 are substantially equal to each other for the turbine blades 22. Each opening 62 communicates with a fuel passage 60 inside the hub 20 via a fuel addition passage 64 provided inside the turbine blade 22.

FIG. 3 is a view of the turbine wheel 15 as viewed from the outlet passage 44. 4 is a cross-sectional view taken along the line DD shown in FIG. As shown in FIG. 4, the fuel addition passage 64 provided in the turbine blade 22 communicates with the opening 62 provided at the edge of the turbine blade 22, and flows into the fuel addition passage 64 from the fuel passage 60. The fuel to be discharged is ejected from the edge of the turbine blade 22.

  According to this configuration, the fuel supplied from the fuel supply device 68 to the fuel passage 60 via the fuel supply passage 66 is ejected from the edge of the turbine blade 22 through the fuel addition passage 64 and the opening 62. The fuel ejected from the opening 62 is vigorously stirred by the rotating turbine blade 22 to promote atomization and vaporization. As a result, the fuel ejected from the opening 62 is in a state of being substantially uniformly mixed with the exhaust flowing in the turbine blade chamber 46 and flows out from the outlet passage 44 to the exhaust passage 4 together with the exhaust. Therefore, even when the exhaust purification device 10 is disposed in the vicinity of the turbine 7, the fuel in a substantially uniformly dispersed and mixed state in the exhaust can flow into the exhaust purification device 10. Thus, it is possible to suitably regenerate the exhaust purification function of the NOx storage reduction catalyst or the particulate filter of the exhaust purification device 10.

  Further, as shown in FIG. 2, each opening 62 is provided so that fuel is ejected into the turbine blade chamber 46, so that the fuel ejected from the opening 62 is variable nozzles such as the nozzle vane 48 and the shaft 50. Adhering to the mechanism is suppressed. Therefore, it is possible to suppress the occurrence of problems such as the movable part of the variable nozzle mechanism being fixed by the added fuel.

  Further, when the fuel addition passage 64 and the opening 62 are configured in the turbine wheel 15 as described above, the fuel ejected from the opening 62 temporarily adheres to the turbine blade 22 and vaporizes, so that the turbine blade 22 Since it is cooled, there is also an effect that thermal fatigue of the turbine blade 22 can be suppressed. Further, since each opening 62 provided in the turbine blade 22 has a rotationally symmetrical positional relationship with respect to the rotation axis of the turbine wheel 15, a fuel addition system such as the opening 62 and the fuel addition passage 64 is provided in the turbine blade 22. Impairing the rotational symmetry of the turbine wheel 15 due to the addition of fuel from the turbine blade 22 is suppressed, and the occurrence of imbalance in the rotational motion of the turbine wheel 15 is suppressed.

  As shown in FIG. 5, the opening for ejecting fuel from the turbine wheel 15 has at least two turbine blades 22 provided at positions that are point-symmetric with respect to the rotation axis of the turbine wheel 15 among the plurality of turbine blades 22. You may provide in the position facing the inner wall face of the turbine shroud 24 in the surface. Here, it is preferable that the positions where the openings 62 are provided on the surface of each turbine blade 22 are substantially equal to each other for each turbine blade 22. In this case, one end of the fuel addition passage 64 is connected to the opening 62 provided on the surface of the turbine blade 22 and the other end is connected to the fuel passage 60 inside the hub 20. Provided.

  6 is a cross-sectional view taken along the line DD shown in FIG. 3 when the fuel addition system in the turbine wheel 15 has the configuration shown in FIG. As shown in FIG. 6, the fuel addition passage 64 provided in the turbine blade 22 communicates with the opening 62 provided on the surface of the turbine blade 22, and flows into the fuel addition passage 64 from the fuel passage 60. The fuel to be discharged is ejected from the surface of the turbine blade 22.

  In the case of this configuration, the fuel supplied from the fuel supply device 68 to the fuel passage 60 via the fuel supply passage 66 is ejected from the surface of the turbine blade 22 through the fuel addition passage 64 and the opening 62. The fuel ejected from the opening 62 is vigorously stirred by the rotating turbine blade 22 to promote atomization and vaporization. As a result, as in the case of the configuration of FIG. 2, the fuel ejected from the opening 62 is in a state of being substantially uniformly mixed with the exhaust flowing in the turbine blade chamber 46. As a result, it becomes possible to supply the fuel in a state of being dispersed and mixed substantially uniformly in the exhaust gas to the exhaust passage 4 downstream from the turbine 7.

  In the case of the configuration of FIG. 5 as well, since the fuel ejected from the opening 62 is ejected into the turbine blade chamber 46, it is possible to suppress the fuel from adhering to the variable nozzle mechanisms such as the nozzle vane 48 and the shaft 50. Further, the fuel ejected from the opening 62 temporarily adheres to the turbine blade 22 and vaporizes, whereby the cooling effect of the turbine blade 22 is obtained, and the thermal deterioration of the turbine blade 22 can be suppressed. Further, since each opening 62 provided in the turbine blade 22 has a rotationally symmetrical positional relationship with respect to the rotation axis of the turbine wheel 15, a fuel addition system such as the opening 62 and the fuel addition passage 64 is provided in the turbine blade 22. Impairing the rotational symmetry of the turbine wheel 15 due to the addition of fuel from the turbine blade 22 is suppressed, and the occurrence of imbalance in the rotational rotation of the turbine wheel 15 can also be suppressed.

  As shown in FIG. 7, the opening for ejecting fuel from the turbine wheel 15 is provided at a position that is point-symmetric with respect to the rotation axis of the turbine wheel 15 in the portion where the turbine blade 22 is not provided on the surface of the hub 20. Alternatively, at least two openings may be used. In this case, the fuel addition passage 64 is provided inside the hub 20 such that one end is connected to the opening 62 provided on the surface of the hub 20 and the other end is connected to the fuel passage 60 inside the hub 20. .

  In the case of this configuration, the fuel supplied from the fuel supply device 68 to the fuel passage 60 via the fuel supply passage 66 is ejected from the surface of the hub 20 through the fuel addition passage 64 and the opening 62. The fuel ejected from the opening 62 collides with the rotating turbine blade 22 and is vigorously stirred to promote atomization and vaporization. Accordingly, similarly to the above-described configurations, it is possible to supply the fuel in a state of being dispersed and mixed substantially uniformly in the exhaust gas to the exhaust passage 4 downstream from the turbine 7.

  Further, as shown in FIG. 7, if the opening 62 is provided at a position where the nozzle vane 48 does not exist on the straight line extending from the opening 62 in the radial direction of the turbine wheel 15, the air is ejected from the opening 62. It is possible to suppress the fuel from adhering to the variable nozzle mechanism including the nozzle vane 48 and the shaft 50.

  Further, if each fuel addition passage 64 is provided in the hub 20 so as to have a point-symmetrical positional relationship with respect to the rotation axis of the turbine wheel 15, the turbine wheel 15 resulting from providing the fuel addition system in the hub 20. It is possible to more reliably suppress the decrease in rotational symmetry.

  In the first embodiment, the configuration in which the fuel is added from the hub 20 or the turbine blade 22 of the turbine wheel 15 is shown. However, the fuel may be added from the inner wall surface of the turbine shroud 24 toward the turbine blade 22. .

  FIG. 8 shows the basic structure of the known variable capacity turbocharger described in the first embodiment. Further, an opening 70 is provided at a position facing the turbine blade 22 on the inner wall surface of the turbine shroud 24. 1 shows a configuration in which fuel is supplied from a fuel supply device 74 via a fuel supply passage 72.

  According to this configuration, the fuel ejected from the opening 70 provided on the inner wall surface of the turbine shroud 24 collides with the rotating turbine blade 22 and is agitated to promote atomization and vaporization. As a result, it is possible to supply fuel in a state of being dispersed and mixed substantially uniformly in the exhaust gas to the exhaust passage downstream of the turbine 7.

In this case, as shown in FIG. 8, the opening 70 is provided on the inner wall surface of the turbine blade chamber 46 on the downstream side of the space in which the nozzle vane 48 is provided (inner wall surface in the range indicated by A in FIG. 8). By doing so, it is possible to suppress the fuel ejected from the opening 70 from adhering to the variable nozzle mechanism including the nozzle vane 48 and the shaft 50. Therefore, it is possible to suppress the occurrence of problems in the operation of the variable nozzle mechanism.

  The embodiments described above can be combined without departing from the spirit of the present invention.

1 is a diagram illustrating a schematic configuration of an internal combustion engine and an intake system and an exhaust system thereof in Embodiment 1. FIG. It is a figure which shows the structure of the turbocharger and fuel addition system in Example 1. FIG. It is the figure which looked at the turbine wheel in Example 1 from the exit passage side of a turbine. 1 is a cross-sectional view of a turbine blade in Example 1. FIG. It is a figure which shows the structure of the turbocharger and fuel addition system in Example 1. FIG. 1 is a cross-sectional view of a turbine blade in Example 1. FIG. It is a figure which shows the structure of the turbocharger and fuel addition system in Example 1. FIG. It is a figure which shows the structure of the turbocharger in Example 2, and a fuel addition system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Cylinder 3 Intake passage 4 Exhaust passage 5 Turbocharger 6 Compressor 7 Turbine 8 Intercooler 9 Air cleaner 10 Exhaust purification device 13 Intake manifold 14 Exhaust manifold 15 Turbine wheel 16 Compressor impeller 18 Rotor shaft 20 Hub 22 Turbine blade 24 Turbine shroud 26 Hub 28 Vane 30 Compressor shroud 34 Bearing 36 Bearing 42 Inlet scroll chamber 44 Outlet passage 46 Turbine blade chamber 48 Nozzle vane 50 Shaft 52 Nozzle vane drive unit 54 Inlet passage 56 Outlet diffuser 58 Compressor vane chamber 60 Fuel passage 62 Opening 64 Fuel addition passage 66 Fuel supply passage 68 Fuel supply device 70 Opening 72 Fuel supply passage 74 Fuel supply device

Claims (7)

A hub disposed in the exhaust passage of the internal combustion engine, connected to a rotor shaft, and a plurality of turbine blades provided on the surface of the hub, and rotatably supported by the rotor shaft, A turbine wheel that rotates around the rotor shaft by receiving a flow of exhaust gas flowing through the turbine blade;
A turbine shroud provided so as to cover the periphery of the turbine wheel outside the turbine wheel;
A fuel passage provided inside the hub and through which fuel flows;
Fuel supply means for supplying fuel to the fuel passage;
An opening provided at a position facing an inner wall surface of the turbine shroud at an edge or surface of at least two turbine blades provided at a position that is point-symmetric with respect to the rotation axis of the turbine wheel among the plurality of turbine blades; ,
A fuel addition passage provided inside each turbine blade provided with the opening, one end connected to the fuel passage inside the hub, and the other end connected to the opening;
An exhaust fuel addition device for an internal combustion engine with a turbocharger, comprising: In claim 1,
Exhaust fuel for an internal combustion engine with a turbocharger, wherein the positions where the openings are provided on the edges or surfaces of the turbine blades are substantially equal to each other, and the openings are point-symmetric with respect to the rotation axis. Addition equipment. In claim 1 or 2,
An exhaust fuel addition apparatus for an internal combustion engine with a turbocharger, wherein each fuel addition passage is provided inside each turbine blade so as to have a point-symmetric positional relationship with respect to the rotation axis. A hub disposed in the exhaust passage of the internal combustion engine, connected to a rotor shaft, and a plurality of turbine blades provided on the surface of the hub, and rotatably supported by the rotor shaft, A turbine wheel that rotates around the rotor shaft by receiving a flow of exhaust gas flowing through the turbine blade;
A fuel passage provided inside the hub and through which fuel flows;
Fuel supply means for supplying fuel to the fuel passage;
At least two openings provided at positions that are point-symmetric with respect to the rotation axis of the turbine wheel in a portion of the surface of the hub where the turbine blade is not provided;
A fuel addition passage provided inside the hub, having one end connected to the fuel passage inside the hub and the other end connected to each opening;
An exhaust fuel addition device for an internal combustion engine with a turbocharger, comprising: In claim 4,
An exhaust fuel addition apparatus for an internal combustion engine with a turbocharger, wherein each of the fuel addition passages is provided inside the hub so as to have a point-symmetric positional relationship with respect to the rotation axis. In any one of Claims 1-5,
A variable nozzle mechanism provided in an exhaust passage formed outside the turbine wheel along a circumferential direction of the turbine wheel and having a nozzle vane for changing a flow passage area of the exhaust passage;
The exhaust fuel addition apparatus for an internal combustion engine with a turbocharger, wherein each opening is provided at a position where the fuel added from each opening through the fuel addition passage does not collide with the nozzle vane. A hub disposed in the exhaust passage of the internal combustion engine, connected to a rotor shaft, and a plurality of turbine blades provided on the surface of the hub, and rotatably supported by the rotor shaft, A turbine wheel that rotates around the rotor shaft by receiving a flow of exhaust gas flowing through the turbine blade;
A variable nozzle mechanism having a nozzle vane that is provided inside an exhaust passage formed outside the turbine wheel along a circumferential direction of the turbine wheel, and changes a flow passage area of the exhaust passage;
An opening provided at a position facing the turbine blade on an inner wall surface of a turbine shroud covering a portion where the exhaust passage is not formed outside the turbine wheel;
A fuel addition passage connected to the opening and through which fuel flows;
Fuel supply means for supplying fuel to the fuel addition passage;
An exhaust fuel addition device for an internal combustion engine with a turbocharger, comprising:

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