JP2007077965A - Variable capacity turbocharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable capacity turbocharger with a smoothly slidable nozzle vane. <P>SOLUTION: The variable capacity turbocharger comprises a housing 201, a drive mechanism 202 provided in the housing 201 for driving a nozzle 42 to regulate the flow of exhaust gas, and a hydrocarbon adsorbent 301 provided adjacent to the drive mechanism 202. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a variable capacity turbocharger, and more particularly to a variable capacity turbocharger provided with a hydrocarbon adsorbent.

  Currently, a variable capacity turbocharger with a mechanism capable of more accurately controlling the amount of air 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 changing the direction of the vanes. The turbine is disclosed in, for example, Japanese Patent Application Laid-Open No. 11-229886 (Patent Document 1), Japanese Patent Application Laid-Open No. 2005-98193 (Patent Document 2) and Japanese Patent Application Laid-Open No. 9-112392 (Patent Document 3).
JP-A-11-229886 JP 2005-98193 A JP-A-9-112392

  In Patent Document 1, a seal structure is provided between the plate and the turbine housing so that unburned hydrocarbon (HC) or the like does not enter the drive portion of the nozzle vane of the VN turbo.

  In Patent Document 2, an oxidation catalyst is coated on the surface of the housing of the VN turbo to promote exhaust purification immediately after startup.

  In patent document 3, the coating layer of the oxidation catalyst is formed in the injection port of the injector.

  In any of the above-described techniques, there is a problem that it is difficult to smoothly operate the drive mechanism that drives the nozzle.

  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 driving a vane with certainty.

  A variable capacity turbocharger according to the present invention includes a housing, a drive mechanism that is provided in the housing and drives a vane for adjusting the flow of exhaust, and a hydrocarbon adsorber that is provided adjacent to the drive mechanism. Is provided.

  In the variable capacity type turbocharger configured as described above, the hydrocarbon adsorbent is provided adjacent to the drive mechanism, so that the hydrocarbon adsorbent can adsorb unburned hydrocarbon. As a result, the hydrocarbon is prevented from adhering to the drive mechanism, and the vane can be driven smoothly.

  Preferably, the housing is provided with an internal space for accommodating the drive unit, and the hydrocarbon adsorbent is disposed in the internal space.

Preferably, the hydrocarbon adsorber constitutes a nozzle plate that holds the vanes.
Preferably, the drive mechanism includes a vane shaft connected to the vane and a nozzle plate that holds the vane shaft. The hydrocarbon adsorber constitutes a bush interposed between the vane shaft and the nozzle plate.

  Preferably, the nozzle plate is provided with a first groove that surrounds the bush and a second groove that continues to the first groove and reaches another space.

  According to the present invention, it is possible to provide a variable capacity turbocharger capable of smoothly driving a vane.

  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)
1 is a schematic configuration diagram showing a diesel engine system according to Embodiment 1 of the present invention. The diesel engine system shown in Fig. 1 combines a high-pressure common-rail fuel injection system, a large-capacity electronically controlled EGR (Exhaust Gas Recirculation) cooler, and a DPNR (Diesel Particulate NOx Reduction) catalyst to achieve clean exhaust for diesel engines. (Particulate Matter) and NOx are continuously and simultaneously reduced. In FIG. 1, an internal combustion engine (hereinafter referred to as an engine) 1000 is an in-line four-cylinder diesel engine having a fuel supply system 100, a combustion chamber 200, an intake system 300, and an exhaust system 400 as main parts. The number of cylinders is not particularly limited, and various shapes such as an in-line type, a V type, a W type, and a horizontally opposed type can be adopted as the shape of the engine. The DPNR 450 can be adopted even if it is a DPF (Diesel Particulate Filter) for regenerating PM.

  The fuel supply system 100 includes a supply pump 110, a common rail 120, a fuel injection valve 130, a shielding valve 140, a metering valve 160, a fuel addition nozzle 170, an engine fuel passage 800, and an addition fuel passage 810.

  The supply pump 110 pumps fuel from the fuel tank, raises the pumped fuel to a high pressure, and supplies the pumped fuel to the common rail 120 via the engine fuel passage 800. The common rail 120 functions as a pressure accumulation chamber that holds (accumulates) the high-pressure fuel supplied from the supply pump 110 at a predetermined pressure, and distributes the accumulated fuel to each fuel injection valve 130. The fuel injection valve 130 includes an electromagnetic solenoid therein, and is appropriately opened to inject fuel into the combustion chamber 200.

  The supply pump 110 supplies a part of the fuel pumped from the fuel tank to the fuel addition nozzle (reducing agent injection nozzle) 170 via the added fuel passage 810. In the addition fuel passage 810, a shielding valve 140 and a metering valve 160 are sequentially arranged from the supply pump 110 toward the fuel addition nozzle 170. The shielding valve 140 blocks the added fuel passage 810 in an emergency and stops the fuel supply. The metering valve 160 controls the pressure (fuel pressure) of the fuel supplied to the fuel addition nozzle 170. The fuel addition nozzle 170 is a mechanical on-off valve that opens when a fuel pressure (for example, 0.2 MPa) equal to or higher than a predetermined pressure is applied and injects fuel into the exhaust system 400 (exhaust port 410). That is, by controlling the fuel pressure upstream of the fuel addition nozzle 170 by the metering valve 160, desired fuel is supplied (added) from the fuel addition nozzle 170 at an optimal timing.

  The intake system 300 constitutes a passage (intake passage) for intake air supplied into each combustion chamber 200. The exhaust system 400 is configured by connecting various passage members such as an exhaust port 410, an exhaust manifold 420, a catalyst upstream side passage 430, and a catalyst downstream side passage 440 in order from upstream to downstream, and exhaust exhausted from each combustion chamber 200. A gas passage (exhaust passage) is formed.

  Further, the engine 1000 is provided with a supercharger (variable capacity turbocharger) 1. The variable displacement turbocharger 1 has a structure in which a compressor wheel 34 and a turbine wheel assembly 22 are connected via a turbine shaft 7. The compressor wheel 34 of the intake system is exposed to intake air in the intake system 300, and the turbine wheel assembly 22 is exposed to exhaust gas in the exhaust system 400. The variable displacement turbocharger 1 having such a configuration performs so-called supercharging in which the compressor wheel 34 is rotated and the intake pressure is increased by utilizing the exhaust pressure (exhaust flow) received by the turbine wheel assembly 22.

  In the intake system 300, the intercooler 310 provided in the variable capacity turbocharger 1 forcibly cools the intake air whose temperature has been increased by supercharging. The throttle valve 320 provided further downstream than the intercooler 310 is an electronically controlled on-off valve whose opening degree can be adjusted steplessly, and the flow area of the intake air is reduced under predetermined conditions. And has a function of adjusting (reducing) the amount of intake air supplied.

  Further, the engine 1000 is formed with an exhaust gas recirculation passage (EGR passage) 600 that bypasses the upstream (intake system 300) and the downstream (exhaust system 400) of the combustion chamber 200. The EGR passage 600 has a function of returning a part of the exhaust to the intake system 300 as appropriate. The EGR passage 600 is opened and closed steplessly by electronic control, and an EGR valve 610 that can freely adjust the flow rate of exhaust gas flowing through the passage, and EGR for cooling the exhaust gas that passes (refluxs) through the EGR passage 600. A cooler 620 is provided.

  In the exhaust system 400, a catalyst 450 composed of DPNR is disposed between the exhaust gas downstream of the turbine wheel assembly 22 (the catalyst upstream side passage 430 and the catalyst downstream side passage 440). The catalyst 450 serves to reduce NOx and PM in the exhaust. Various sensors are attached to each part of the engine 1000, and signals related to the environmental conditions of each part and the operating state of the engine 1000 are output.

  For example, the rail pressure sensor 700 outputs a detection signal corresponding to the fuel pressure stored in the common rail 120. The fuel pressure sensor 710 outputs a detection signal corresponding to the pressure (fuel pressure) Pg of the fuel introduced into the metering valve 160 among the fuel flowing through the added fuel passage 810. The air flow meter 720 outputs a detection signal corresponding to the flow rate (intake amount) Ga of intake air downstream of the throttle valve 320 in the intake system 300. The air-fuel ratio (A / F) sensor 730 outputs a detection signal that continuously changes in accordance with the oxygen concentration in the exhaust gas downstream of the catalyst casing of the intake system 300. Similarly, the exhaust temperature sensor 740 outputs a detection signal corresponding to the exhaust temperature (exhaust temperature) Tex at the downstream of the catalyst casing of the exhaust system 400.

  The accelerator opening sensor 750 is attached to the accelerator pedal of the engine 1000 and outputs a detection signal corresponding to the depression amount Acc of the pedal. The crank angle sensor 760 outputs a detection signal (pulse) every time the output shaft (crankshaft) of the engine 1000 rotates by a certain angle. Each of these sensors 700 to 760 is electrically connected to an electronic control unit (ECU, also referred to as an engine control unit) 1100. ECU 1100 includes a CPU (Central Processing Unit), ROM, RAM and backup RAM, a timer, a counter, and the like, and these are bidirectional with an external input circuit and an external output circuit including an analog / digital (A / D) converter. Connected by a sex bus.

  Next, an outline of the basic principle of fuel addition performed by the engine control unit 1100 will be described.

  In general, in a diesel engine, the oxygen concentration of the mixture of fuel and air used for combustion in the combustion chamber is high in most operating conditions.

  The oxygen concentration in the gas used for combustion is usually reflected in the oxygen concentration in the exhaust as it is subtracted from the oxygen used for combustion. If the oxygen concentration (air-fuel ratio) in the mixture is high, The oxygen concentration (air-fuel ratio) in the exhaust gas basically increases similarly.

On the other hand, as described above, the NOx storage reduction catalyst has a characteristic of absorbing NOx if the oxygen concentration in the exhaust gas is high and reducing NOx to NO ₂ or NO if it is low, so that the oxygen concentration in the exhaust gas is low. As long as the concentration is high, NOx is absorbed. However, when there is a limit amount in the NOx absorption amount of the catalyst and the catalyst absorbs the limit amount of NOx, NOx in the exhaust gas is not absorbed by the catalyst and passes through the catalyst casing.

Therefore, in an internal combustion engine having a fuel addition nozzle 170 such as the engine 1000, an appropriate amount of fuel is added to the upstream of the catalyst 450 of the exhaust system 400 through the fuel addition nozzle 170 at an appropriate time (hereinafter referred to as exhaust addition). Temporarily reduce the concentration of oxygen in the exhaust gas and increase the amount of reducing components (such as Hc). Then, the catalyst 450 reduces and releases the NOx absorbed so far to NO ₂ or NO, and recovers (regenerates) the NOx absorption capability. The released NO ₂ or NO reacts with HC or CO and is quickly reduced to N ₂ .

  In this embodiment, an example in which the fuel addition nozzle 170 is provided is shown, but such a fuel addition nozzle 170 may not be provided.

  Although a common rail type diesel engine has been described, the present invention is not limited to this, and the present invention can also be applied to a diesel engine having a normal row type or distribution type injection pump.

  Next, the structure of the turbine will be described. 2 is a perspective view including a partial cross section of the variable capacity turbocharger according to the first embodiment of the present invention, and FIG. 3 is a cross sectional view taken along line III-III in FIG. 2 and 3, variable displacement turbocharger 1 according to the first embodiment of the present invention is a variable nozzle type turbocharger, and includes housing 201 and turbine shaft rotatably housed in housing 201. 7 and a compressor wheel 34 and a turbine wheel assembly 22 attached to the turbine shaft 7.

  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. The compressor housing 2 has a shape that allows air to be taken in from the center and discharged to the outside. Specifically, air is introduced into the central portion of the compressor housing 2, and this air is accelerated and compressed in the outward direction (radial direction) by the rotating compressor wheel 34, and the compressed air is guided to the intake manifold. It is burned.

  A compressor wheel 34 is accommodated in the compressor housing 2. The compressor wheel 34 is fixed to the turbine shaft 7 and rotates together with the turbine shaft 7. The compressor wheel 34 is fixed to the turbine 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 are accelerated and compressed in the radial direction by centrifugal force.

  A seal ring collar 25 is disposed adjacent to the compressor wheel 34. The seal ring collar 25 has a shape surrounding the turbine shaft 7.

  The center housing 36 is provided at the center of the variable capacity turbocharger 1. The center housing 36 is provided with a thrust bearing 26. The thrust bearing 26 is a bearing for receiving a load in the thrust direction of the turbine shaft 7 and is lubricated by oil or the like.

  The center housing 36 is provided with a floating bearing 24 for holding the rotation of the turbine shaft 7. The floating bearing 24 holds a load in the radial direction of the turbine shaft 7. An oil film is interposed between the floating bearing 24 and the turbine shaft 7, and the floating bearing 24 is not in direct contact with the turbine shaft 7. Further, an oil film is also present between the floating bearing 24 and the center housing 36, and the floating bearing 24 is not in direct contact with the center housing 36.

The floating bearing 24 is positioned by a retainer ring 30.
A drive mechanism 202 as a link mechanism is disposed in the center housing 36 and the turbine housing 48. The drive mechanism 202 includes a unison ring 45 housed in the link chamber 6, an arm 44 positioned on the inner peripheral side of the unison ring 45, and a nozzle plate 43 provided adjacent to the turbine housing 48. And a main arm 37 for driving a plurality of arms 44, a vane shaft 21 connected to the arms 44 for driving the nozzle vanes 42, and a nozzle plate 43 for holding the vane shafts 21.

  The drive mechanism 202 is a mechanism for adjusting the angles of the plurality of nozzle vanes 42. When the pin 40 is rotated by a predetermined angle, the rotation is transmitted to the nozzle vanes 42, and the nozzle vanes 42 are rotated. Has been. Specifically, the pin 40 is connected to a drive link 41, and the drive link 41 is rotatable about a drive shaft 39. A bush 38 is provided on the outer periphery of the drive shaft 39, and the bush 38 is interposed between the drive shaft 39 and the center housing 36. The drive shaft 39 is connected to the main arm 37, and this rotation is transmitted to the main arm 37 when the drive shaft 39 rotates. An inner end portion of the main arm 37 is fixed to the drive shaft 39, and an outer end portion is engaged with the unison ring 45. Therefore, the main arm 37 rotates around the drive shaft 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 45, and when the unison ring 45 rotates, this rotation is transmitted to the arm 44. The arm 44 can rotate about the vane shaft 21, and the rotation of the arm 44 is transmitted to the vane shaft 21. Since the vane shaft 21 is connected to the nozzle vane 42, the nozzle vane 42 rotates together with the vane shaft 21 and the arm 44.

  The nozzle plate 43 is in contact with the turbine housing 48, and the link chamber 6 is provided between the turbine housing 48 and the center housing 36. The link chamber 6 is an internal space for storing the drive mechanism. The turbine housing 48 is provided with a turbine housing vortex chamber, and exhaust gas is supplied to the turbine housing vortex chamber, and the flow of the exhaust gas rotates the turbine wheel assembly 22. The rotation of the turbine wheel assembly 22 is transmitted to the compressor wheel 34 via the turbine shaft 7. Spacer bolts 47 are attached to the turbine housing 48.

  Referring to FIG. 1, drive link 41 of drive mechanism 202 is connected to motor rod 302. The motor rod 302 is a rod-shaped member and is connected to the link 303 and the variable nozzle controller 270. The variable nozzle controller 270 is connected to a direct current motor (DC motor). When the direct current motor rotates, the rotation is transmitted to the link 303 via the gear mechanism and the worm mechanism, and is driven from the link 303 via the motor rod 302. The link 41 is moved.

  The position of the link 303 is detected by an opening degree sensor 304, and the opening degree sensor 304 measures the position of the link 303. Thereby, the inclination angle of the nozzle vane 42 as the variable nozzle is detected.

  A hydrocarbon adsorbent 301 is disposed in the link chamber 6. The hydrocarbon adsorbent 101 is a member that adsorbs unburned hydrocarbon, and is composed of, for example, an oxidation catalyst or a charcoal filter. When the hydrocarbon adsorbent 301 is constituted by an oxidation catalyst, the unburned hydrocarbon is purified by forcibly oxidizing the unburned hydrocarbon contained in the exhaust gas. Thereby, the sliding failure of the nozzle vane 42 can be avoided.

  Further, when the hydrocarbon adsorbent 301 is a charcoal filter, unburned hydrocarbon is adsorbed on the same principle as a canister employed in a combustion system of a gasoline engine. When the exhaust gas to which fuel is added for PM regeneration is low temperature, unburned hydrocarbon (HC) is adsorbed by this adsorbent. The filter itself is regenerated when the engine is under heavy load (the exhaust gas temperature is high and the filter ambient temperature is high). Further, a passage through which the adsorbed fuel flows to another region may be provided in the center housing 36 or the turbine housing 48.

  FIG. 4 is a front view of the variable capacity turbocharger as seen from the direction indicated by arrow IV in FIG. Referring to FIG. 4, nozzle vanes 42 as variable nozzles are arranged between turbine wheel assemblies 22 so as to be spaced apart from each other by an equal distance. The nozzle vane 42 is positioned on the nozzle plate 43 and can be rotated by a predetermined angle around the vane shaft 21 at the center thereof. Exhaust gas is supplied from the outer circumference to the inner circumference side of the disc-shaped nozzle plate 43, and the exhaust gas passes through the adjacent nozzle vanes 42 and reaches the turbine wheel assembly 22 to rotate the turbine wheel assembly 22. FIG. 4 shows a state where the adjacent nozzle vanes 42 are most open, and shows a state where the exhaust gas flow rate becomes the largest.

  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 270 and an engine control unit 1100. Specifically, the engine control unit 1100 determines the required variable nozzle opening based on the ignition switch, accelerator opening, engine speed, atmospheric pressure, atmospheric temperature, supercharging pressure, cooling water temperature, and the like. This determined data is transmitted to the variable nozzle controller 270. The variable nozzle controller 270 gives the drive output of the DC motor to the variable capacity turbocharger 1 based on the above data, and the opening degree of the nozzle is determined. In the variable displacement turbocharger 1, the engine vane 42 is opened and closed by a motor as a variable nozzle provided on the outer periphery of the turbine wheel assembly, and the flow rate and pressure of the exhaust gas input to the turbocharger are adjusted, whereby the engine speed and It becomes possible to optimally control the balance between the back pressure and the supercharging pressure according to the load.

  FIG. 6 is a perspective view of the hydrocarbon adsorbent according to the first embodiment of the present invention. Referring to FIG. 6, hydrocarbon adsorbent 301 is annular and has a shape in which a cavity is provided at the center. This hollow portion is fitted into the center housing 36. The thickness of the hydrocarbon adsorbent 301 is preferably as thick as possible so as not to interfere with the variable nozzle mechanism. Next, the driving of the nozzle vanes will be described in detail.

  FIG. 7 is a front view of the drive mechanism shown for explaining the opened nozzle vane. FIG. 8 is a rear view of the drive mechanism shown for explaining the opened nozzle vane. Referring to FIGS. 7 and 8, a disc-shaped nozzle plate 43 is fitted on the inner periphery of an annular unison ring 45. The nozzle plate 43 is fixed to the turbine housing. The unison ring 45 is slidable with respect to the nozzle plate 43. A main arm 37 and an arm 44 are fitted in a recess 245 provided on the outer periphery of the unison ring 45. Each of the arms 44 is connected to a nozzle vane 42, and the nozzle vane 42 can be rotated by a predetermined angle. It is possible to adjust the flow rate and flow velocity of the exhaust from the turbine housing vortex chamber to the exhaust turbine chamber by the rotation angle of the nozzle vane 42.

  A drive shaft 39 is provided so as to penetrate the nozzle plate 43, and the drive shaft 39 is connected to the main arm 37. When the main arm 37 rotates around the drive shaft 39, the unison ring 45 engaged with the main arm 37 rotates in the direction indicated by the arrow 445. With this rotation, the arm 44 also rotates about the vane shaft 21. The vane shaft 21 rotates, this rotation is transmitted to the nozzle vane 42, and the nozzle vane 42 rotates. 7 and 8, the motor rod 302 is pulled in the direction indicated by the arrow 403.

  A pin 52 is inserted into the nozzle plate 43, and a roller 51 is fitted over the pin 52. The roller 51 guides the inner peripheral surface of the unison ring 45. Thereby, the unison ring 45 is held by the roller 51 and can be rotated in a predetermined direction.

  FIG. 9 is a front view of a drive mechanism shown for explaining a closed nozzle vane. FIG. 10 is a rear view of the drive mechanism shown for explaining the closed nozzle vane. Referring to FIGS. 9 and 10, when closing nozzle vane 42, motor rod 302 is pushed in the direction indicated by arrow 503. This pushing is transmitted to the drive shaft 39 via the drive link 41, and the drive shaft 39 rotates. As a result, the tip of the drive shaft 39 rotates the unison ring 45 in the direction indicated by the arrow 545. With this rotation, the arm 44 fitted in the recess 245 of the unison ring 45 rotates in the direction indicated by the arrow 545. The vane shaft 21 and the nozzle vane 42 connected to the arm 44 also rotate in the same direction, so that the nozzle vane 42 rotates so that the space between the adjacent nozzle vanes 42 is closed. Thereby, the clearance gap between the nozzle vanes 42 is closed, and a nozzle is closed.

  A variable capacity turbocharger 1 according to the present invention is provided adjacent to a housing 201, a drive mechanism 202 that is provided in the housing 201 and drives a nozzle vane 42 as a vane for adjusting the flow of exhaust, and the drive mechanism 202. And a hydrocarbon adsorbent 301 provided as described above. The housing 201 is provided with a link chamber 6 as an internal space for housing the drive mechanism 202, and a hydrocarbon adsorbent 301 is disposed in the link chamber 6.

  In the variable capacity turbocharger according to the first embodiment configured as described above, since the hydrocarbon adsorbent 301 is provided in the vicinity of the drive mechanism 202, this unburned fuel is present even if unburned fuel is present. The fuel (hydrocarbon) is adsorbed by the hydrocarbon adsorbent 301. As a result, the sliding failure of the nozzle vane 42 can be prevented.

  In the present invention, as a method for injecting fuel, not only an injector for adding fuel to the exhaust manifold portion as shown in FIG. 1 but also post injection into a cylinder with an existing injector may be used. Good.

(Embodiment 2)
FIG. 11 is a diagram showing the flow of exhaust gas in the variable capacity turbocharger according to the second embodiment of the present invention. In the second embodiment, the material of the nozzle plate 43, which is a component of the variable capacity turbocharger, is changed to a hydrocarbon adsorbent. The material of the nozzle plate is generally made of stainless steel or the like.

  By changing the material of the nozzle plate, which is a component of the variable capacity turbocharger, unburned hydrocarbons that have entered the nozzle vane sliding part of the variable capacity turbocharger without flowing to the aftertreatment catalyst Adsorption is performed by the adsorbent, and the sliding failure of the nozzle vane is avoided. That is, as shown in FIG. 11, fuel is added to the exhaust gas discharged from the engine, and this fuel is sent to the post-treatment catalyst via the VN turbo (variable capacity turbocharger) and then released to the atmosphere. Is done. Fuel is added to the exhaust gas discharged from the engine, and a part of the added fuel penetrates into the VN turbo, and the added fuel enters the nozzle vane sliding portion to cause sliding failure. In this embodiment, by changing the material of the nozzle plate, which is a component inside the turbo, to activated carbon or the like that adsorbs unburned hydrocarbons, trapping the added fuel that has entered the variable capacity turbocharger, The sliding failure of the nozzle vane can be avoided.

  Regeneration is performed when the exhaust gas is hot. Alternatively, it is possible to provide a passage vertically below the plate and discharge the adsorbed hydrocarbons to the scroll side or unison ring side.

  FIG. 12 is a sectional view of a variable capacity turbocharger according to the second embodiment of the present invention. Referring to FIG. 12, in variable capacity turbocharger 1 according to Embodiment 2 of the present invention, variable capacity according to Embodiment 1 is that nozzle plate 343 constitutes a hydrocarbon adsorbent. Different from type turbocharger. The nozzle plate 43 can be composed of an oxidation catalyst or a charcoal filter. Unburned hydrocarbons adsorbed by the nozzle plate 343 may be discharged to the region 501 or the region 502. Specifically, a passage may be provided in the nozzle plate 343 or the turbine housing 48, and the adsorbed hydrocarbon (HC) component may be sent to the unison ring side region 501 or the scroll chamber side region 502 through the passage. .

  That is, in the variable capacity turbocharger 1 according to the second embodiment, the hydrocarbon adsorber constitutes the nozzle plate 343 that holds the nozzle vanes 42.

(Embodiment 3)
FIG. 13 is a sectional view of a variable capacity turbocharger according to the third embodiment of the present invention. 14 is an enlarged cross-sectional view of a portion surrounded by XIV in FIG. Referring to FIGS. 13 and 14, in variable displacement turbocharger 1 according to the third embodiment of the present invention, bush 421 is provided around vane shaft 21, and this bush 421 constitutes a hydrocarbon adsorbent. This is different from the variable capacity turbocharger 1 according to the first and second embodiments. The bush 421 has a cylindrical shape and surrounds the vane shaft 21. It should be noted that holes may be provided at several locations on the bush 421. The bush 421 is interposed between the vane shaft 21 and the nozzle plate 43 and functions to absorb unburned hydrocarbons adhering to the vane shaft 21. In this embodiment, a plurality of vane shafts 21 are provided, but it is not necessary to provide the bushes 421 on all of the plurality of vane shafts 21, and the bushes 421 may be provided on any of the plurality of vane shafts 21.

  FIG. 15 is an enlarged cross-sectional view of a portion surrounded by XV in FIG. Referring to FIG. 15, an annular groove 321 may be provided in nozzle plate 43 so as to surround bush 421. In FIG. 15, the annular groove 321 is configured to extend on substantially the same plane, but is not limited thereto, and a spiral annular groove 321 may be provided. The annular groove 321 is provided with a discharge groove 521. The discharge groove 521 extends downward from the upper side, and has one end connected to the annular groove 321 and the other end opened to the turbine housing vortex chamber side.

  The bush 421 adsorbs unburned hydrocarbons, and the adsorbed hydrocarbons are discharged to the turbine housing vortex chamber side via the grooves 321 and 521.

  FIG. 16 is another sectional view of a variable capacity turbocharger according to the third embodiment of the present invention. Referring to FIG. 16, groove 521 may be provided so as to continue to link chamber 6. One end of the groove 521 is connected to the annular groove 321 and the other end is opened to the link chamber 6 side.

  That is, in Embodiment 3, the bush 421 for adsorbing unburned hydrocarbons is inserted into the sliding portion of the nozzle plate 43 which is a component of the variable capacity turbocharger 1. Thereby, the added fuel that has entered the variable capacity turbocharger 1 is trapped, and the sliding failure of the nozzle vane 42 is avoided.

  Various methods for regenerating the bush 421 that adsorbs unburned hydrocarbons are conceivable. However, a redox reaction at the time of exhaust gas high temperature is used, or a groove 521 that leads to a direction perpendicular to the bush 421 is provided. The adsorbed hydrocarbon component is discharged to the unison ring side or scroll side.

  In the variable capacity turbocharger according to the third embodiment, the drive mechanism 202 includes the vane shaft 21 connected to the nozzle vane 42 and the nozzle plate 43 that holds the vane shaft 21, and the hydrocarbon adsorbent is a vane. A bushing 421 interposed between the shaft 21 and the nozzle plate 43 is configured. Further, a groove 321 that surrounds the bush 421 and a groove 521 that continues to the groove 321 and reaches another space are provided in the nozzle plate 43.

  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 together with a diesel engine. However, the present invention is not limited to this, and the variable capacity turbocharger 1 according to the present invention is provided in a gasoline engine or a rotary engine. May be. 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 displacement turbochargers, in which the amount of intake air supplied to the turbine can be appropriately changed.

1 is a schematic configuration diagram showing a diesel engine system according to Embodiment 1 of the present invention. 1 is a perspective view including a partial cross section of a variable capacity turbocharger according to a first embodiment of the present invention. It is sectional drawing along the III-III line in FIG. FIG. 4 is a front view of the variable capacity turbocharger as viewed from a direction indicated by an arrow IV in FIG. 2. It is a block diagram which shows the control mechanism of the variable capacity | capacitance type turbocharger according to Embodiment 1 of this invention. 1 is a perspective view of a hydrocarbon adsorbent according to Embodiment 1 of the present invention. It is a front view of the drive mechanism shown in order to demonstrate the opened nozzle vane. It is a rear view of the drive mechanism shown in order to demonstrate the opened nozzle vane. It is a front view of the drive mechanism shown in order to demonstrate the closed nozzle vane. It is a rear view of the drive mechanism shown in order to demonstrate the closed nozzle vane. It is a figure which shows the flow of the exhaust gas in the variable capacity | capacitance type turbocharger according to Embodiment 2 of this invention. It is sectional drawing of the variable capacity | capacitance type turbocharger according to Embodiment 2 of this invention. It is sectional drawing of the variable capacity | capacitance type turbocharger according to Embodiment 3 of this invention. It is sectional drawing which expands and shows the part enclosed by XIV in FIG. It is sectional drawing which expands and shows the part enclosed by XV in FIG. It is another sectional view of the variable capacity type turbocharger according to the third embodiment of the present invention.

Explanation of symbols

  1 Variable displacement turbocharger, 2 Compressor housing, 3 Turbine housing vortex chamber, 6 Link chamber, 7 Turbine shaft, 21 Vane shaft, 22 Turbine wheel assembly, 24 Floating bearing, 25 Seal ring collar, 26 Thrust bearing, 30 Retainer ring , 34 Compressor wheel, 35 Lock nut, 36 Center housing, 37 Main arm, 38 Bush, 39 Drive shaft, 40 pin, 41 Drive link, 42 Nozzle vane, 43 Nozzle plate, 44 arm, 45 Unison ring, 47 Spacer bolt, 48 Turbine housing, 148 Exhaust turbine chamber, 201 housing, 202 drive mechanism, 245 recess, 301 hydrocarbon adsorber, 302 module Taroddo, 303 links, 304 opening sensor, 421 Bush.

Claims (5)

A housing;
A drive mechanism provided in the housing for driving a vane for adjusting the flow of exhaust;
A variable capacity turbocharger comprising a hydrocarbon adsorber provided adjacent to the drive mechanism.   2. The variable capacity turbocharger according to claim 1, wherein the housing is provided with an internal space for housing the drive unit, and the hydrocarbon adsorbent is disposed in the internal space.   The variable capacity turbocharger according to claim 1, wherein the hydrocarbon adsorber constitutes a nozzle plate that holds the vane.   The drive unit includes a vane shaft connected to the vane and a nozzle plate that holds the vane shaft, and the hydrocarbon adsorber constitutes a bush interposed between the vane shaft and the nozzle plate. The variable capacity turbocharger according to claim 1.   The variable capacity turbocharger according to claim 4, wherein a first groove that surrounds the bush and a second groove that continues to the first groove and reaches another space are provided in the nozzle plate.

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