JP2006194176A - Variable nozzle turbo-charger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress an exhaust gas cleaning fuel and soot from being intruded into a link chamber with an exhaust gas and thereby to avoid that motion of a link mechanism is obstructed due to the fact that it is deposited and accumulated on a wall surface of the link chamber and the link mechanism. <P>SOLUTION: The variable nozzle turbo-charger 16 is provided with a turbine housing 45 having exhaust flow passages (scroll passage 46 and nozzle passage 47) around a turbine wheel; a plurality of nozzle vanes provided on the nozzle passage 47; and the link mechanism 55 provided in the link chamber 54 surrounded by a plurality of members including the turbine housing 45 and connected to the plurality of nozzle vanes 53. In the variable nozzle turbo-charger 16 having such a constitution, a communication passage 65 for communicating the scroll passage 46 and the link chamber 54 and storing the exhaust gas flowing between the scroll passage 46 and the link chamber 54 accompanying with fluctuation of the exhaust gas pressure is provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a variable nozzle turbocharger that includes a variable nozzle in a flow path of exhaust gas blown to a turbine wheel and adjusts the flow rate of exhaust gas by changing the opening of the variable nozzle.

  In a general turbocharger mounted on an engine, a turbine wheel is provided in a turbine housing, and a compressor wheel is provided in a compressor housing, and these turbine wheel and compressor wheel are supported by a center housing on a rotor shaft. Are connected so as to be integrally rotatable. In this turbocharger, when the exhaust gas flowing through the exhaust passage of the engine flows into the turbine housing, the exhaust gas is blown to the turbine wheel after passing through the exhaust passage around the turbine wheel. When the turbine wheel is rotated by this exhaust blowing, the rotation is transmitted to the compressor wheel via the rotor shaft. As the compressor wheel rotates in this way, the air flowing through the intake passage of the engine is compressed in the process of passing through the compressor housing. This compression increases the air pressure (supercharging pressure), and as a result, the air is forcibly fed into the combustion chamber of the engine.

Further, as one form of the turbocharger, there is a variable nozzle turbocharger provided with a plurality of variable nozzles in the exhaust flow passage in the turbine housing and adjusting the flow rate of the exhaust gas by changing the opening degree of the variable nozzles. It is known (see, for example, Patent Document 1). The plurality of variable nozzles are arranged at substantially equal angles around the turbine wheel. These variable nozzles are rotatably supported by a nozzle ring disposed between the center housing and the exhaust passage. A space surrounded by the turbine housing, the center housing and the nozzle ring is a link chamber, and an actuator is connected to the variable nozzle via a link mechanism provided in the link chamber. Therefore, when the actuator is actuated, the movement is transmitted to all the variable nozzles through the link mechanism, and the variable nozzles are synchronously rotated in the same direction. By this rotation, the gap between the adjacent variable nozzles changes, and the flow rate of the exhaust gas blown to the turbine wheel through the gap is adjusted.
JP 2003-49675 A

  However, when the variable nozzle turbocharger is applied to a diesel engine in which fuel for exhaust purification is injected separately from injection of fuel used for combustion in the combustion chamber, the following phenomenon occurs. May happen.

  In the variable nozzle turbocharger, there is a considerable gap between its constituent members, for example, between the turbine housing and the nozzle ring. Therefore, when the exhaust pressure in the exhaust passage rises and becomes higher than the exhaust pressure in the link chamber, a part of the exhaust flows into the link chamber through the gap on the way from the exhaust passage to the turbine wheel. At this time, a suit made of particulate matter (PM) contained in the exhaust also enters the link chamber together with the exhaust. Further, the fuel injected for exhaust purification does not vaporize sufficiently when the exhaust temperature is low, or aggregates on the surface of the low-temperature turbine housing. Such insufficiently vaporized fuel or agglomerated fuel also rides on the exhaust gas and enters the link chamber through the gap.

  On the other hand, the temperature of the wall surface of the link chamber and the link mechanism is lower than the temperature of the exhaust passage. The temperature of exhaust in the link chamber is low on the wall surface of the link chamber and the surface of the link mechanism, and increases as the distance from the wall surface and link mechanism increases. When such a temperature gradient is large, the exhaust purification fuel in the exhaust adheres to the wall surface of the link chamber and the link mechanism by thermophoresis. Then, the suit in the exhaust adheres and accumulates at a location wetted by the fuel. When the exhaust purification fuel adheres and the suit adheres and accumulates, the deposits may hinder the movement of the link mechanism.

  The above-mentioned patent document 1 describes a technique for estimating the time when the variable nozzle is fixed and forcibly opening and closing the variable nozzle before the estimated time. According to this technology, when a suit is deposited and sticking is likely to occur, the suit can be removed by forcibly opening and closing the variable nozzle, but the exhaust purification fuel that causes the sticking of the suit can be removed. There is no consideration for suppressing adhesion and adhesion / deposition of the suit.

  The present invention has been made in view of such circumstances, and the object thereof is to suppress the exhaust purification fuel and the suit from entering the link chamber together with the exhaust gas, and thus adhere to the wall surface of the link chamber and the link mechanism. It is to provide a variable nozzle turbocharger that can be prevented from accumulating and preventing the movement of the link mechanism.

In the following, means for achieving the above object and its effects are described.
The invention according to claim 1 is used in a diesel engine that injects fuel for purifying exhaust gas, and has a turbine housing having an exhaust passage around the turbine wheel for guiding exhaust gas to the turbine wheel. A plurality of variable nozzles provided in the exhaust passage, and a link mechanism provided in a link chamber surrounded by a plurality of members including the turbine housing and connected to the plurality of variable nozzles, In the variable nozzle turbocharger configured to adjust the flow velocity of the exhaust gas blown to the turbine wheel through the gap between adjacent variable nozzles by changing the opening of the plurality of variable nozzles through a link mechanism, The exhaust flow path and the link chamber communicate with each other, and the exhaust flow path and the link are associated with fluctuations in exhaust pressure. Further comprising a communication passage for storing the exhaust gas flowing between.

  According to the above configuration, in the variable nozzle turbocharger, the exhaust of the diesel engine is sprayed to the turbine wheel through the gap between the adjacent variable nozzles in the process of flowing through the exhaust passage in the turbine housing. Further, when the opening degree of the plurality of variable nozzles provided in the exhaust flow path is adjusted through the link mechanism, the gap between the adjacent variable nozzles changes in accordance with the adjustment, and the turbine wheel passes through the gap to the turbine wheel. The flow rate of the exhausted air changes.

  Here, when the exhaust pressure in the exhaust passage increases, a part of the exhaust flowing through the exhaust passage flows into the communication path. When the exhaust gas includes a suit and an exhaust purification fuel that is not sufficiently vaporized due to a low exhaust temperature, the exhaust enters the communication path together with the suit and the exhaust purification fuel. Accordingly, a part of the exhaust gas existing in the communication path is pushed out from the communication path to the link chamber. Therefore, the exhaust gas containing the suit and the exhaust purification fuel and entering the communication passage from the exhaust passage is temporarily stored in the communication passage, and is difficult to reach the link chamber.

Further, the amount of the suit and the exhaust purification fuel entering the link chamber through the gaps between the plurality of members forming the link chamber is reduced by the amount that enters the communication path as described above.
In this way, the suit and exhaust purification fuel that enter the link chamber from the exhaust flow path together with the exhaust gas are reduced. Therefore, even if the temperature of the wall of the link chamber and the link mechanism is lower than the temperature of the exhaust flow path, the amount of exhaust purification fuel and suit that adheres to and accumulates on the wall of the link chamber and the link mechanism is reduced by thermophoresis. However, the operation of the link mechanism is less likely to be hindered.

  Contrary to the above, when the exhaust pressure in the exhaust passage decreases, a part of the exhaust in the link chamber moves to the communication passage, and the exhaust gas (suit and exhaust purification fuel is removed) that enters the communication passage in the communication passage. Including) is returned to the exhaust passage.

  According to a second aspect of the present invention, in the first aspect of the present invention, the communication passage stores exhaust gas flowing between the exhaust flow path and the link chamber through the communication passage as the exhaust pressure fluctuates. It is assumed that a storage chamber, an introduction path that connects the exhaust passage and the storage chamber, and a lead-out path that connects the storage chamber and the link chamber are provided.

  According to the above configuration, when the exhaust pressure of the exhaust passage increases, a part of the exhaust flowing through the exhaust passage enters the storage chamber from the exhaust passage through the introduction passage together with the suit and the exhaust purification fuel. . Along with this, a part of the exhaust gas existing in the storage chamber is pushed out from the lead-out path to the link chamber. Therefore, the exhaust gas that includes the suit and the exhaust purification fuel and enters the storage chamber from the exhaust passage is temporarily stored in the storage chamber, and is difficult to reach the link chamber.

  Contrary to the above, when the exhaust pressure in the exhaust passage decreases, a part of the exhaust in the link chamber moves from the link chamber to the storage chamber through the lead-out passage, and enters the storage chamber when the pressure increases. Exhaust gas (including suit and exhaust purification fuel) is pushed out and returned to the exhaust passage.

  According to a third aspect of the present invention, in the second aspect of the present invention, the end of the introduction path on the exhaust flow path side is projected from the inner wall surface of the turbine housing into the exhaust flow path.

  According to the above configuration, the exhaust purification fuel contained in the exhaust gas may adhere to the inner wall surface of the turbine housing that has been cooled by the outside air and cooled to a low temperature in the course of flowing through the exhaust passage. At this time, if the end of the introduction path on the exhaust flow path side is opened at the inner wall surface of the turbine housing, the attached exhaust purification fuel may enter the introduction path from this opening. In this regard, in the invention described in claim 3, the end of the introduction path on the exhaust flow path side protrudes from the inner wall surface of the turbine housing into the exhaust flow path. This projecting portion serves as a barrier to restrict the exhaust purification fuel adhering to the inner wall surface from entering the introduction passage from the exhaust passage side opening of the introduction passage. Therefore, it is possible to further suppress the exhaust purification fuel in the exhaust from entering the link chamber through the communication path.

  According to a fourth aspect of the present invention, in the second or third aspect of the invention, the storage chamber is provided outside the turbine housing, and the end portion of the introduction path on the storage chamber side is provided in the storage chamber. Suppose that it protrudes inward from the wall surface.

  Further, in the invention according to claim 5, in the invention according to any one of claims 2 to 4, the storage chamber is provided outside the turbine housing, and an end of the outlet path on the storage chamber side is provided. It is assumed that the portion protrudes inward from the wall surface of the storage chamber.

  According to said structure, the storage chamber is provided in the exterior of the turbine housing, and is cooled with external air, and temperature is low. As for the storage chamber, the temperature is the lowest on the wall surface, and the temperature increases as the distance from the wall surface increases. When the temperature gradient in the storage chamber is large, the exhaust purification fuel in the exhaust adheres to the wall surface of the storage chamber by thermophoresis, and the suit in the exhaust adheres and accumulates at a location wetted by the fuel.

  Here, if the end portion on the storage chamber side of the introduction path is open to the wall surface of the storage chamber, the opening is blocked or narrowed by the suit deposited as described above, and the introduction path and There is a possibility that the flow of exhaust gas between the storage chambers may be hindered.

  In this respect, in the invention described in claim 4, the end portion of the introduction path on the storage chamber side protrudes from the wall surface of the storage chamber to the inside. Due to this protrusion, the temperature of the end of the introduction path on the storage chamber side, particularly the opening, becomes higher than the wall surface of the storage chamber described above. For this reason, it is difficult for the exhaust purification fuel and the suit to adhere to and accumulate in the opening due to thermophoresis, and it is difficult to cause a problem that the flow of the exhaust is hindered by the deposit between the introduction path and the storage chamber.

  In addition, if the end of the lead-out path on the storage chamber side opens on the wall surface of the storage chamber, the opening is closed or narrowed by the suit deposited as described above, and the storage chamber and the lead-out There is a risk that the flow of exhaust gas between the roads may be hindered.

  In this regard, in the invention described in claim 5, the end of the lead-out path on the storage chamber side protrudes from the wall surface of the storage chamber toward the inside. Due to this protrusion, the temperature of the end of the outlet passage on the storage chamber side, particularly the opening, becomes higher than the wall surface of the storage chamber described above. Therefore, it is difficult for the exhaust purification fuel and the suit to adhere to and accumulate in the opening due to thermophoresis, and it is difficult to cause a problem that the flow of the exhaust is hindered by the deposit between the storage chamber and the outlet passage.

  In the invention according to claim 6, in the invention according to any one of claims 2 to 5, the storage chamber includes an opening portion of the introduction path and an opening portion of the outlet path in the storage chamber. It is assumed that a partition member is provided for forming a passage connecting in a meandering state.

  According to the above configuration, since the exhaust passage connecting the opening portion of the introduction path and the opening portion of the outlet path in the storage chamber is meandering, the passage length is longer than that in the case where the exhaust passage is not meandering. For this reason, when exhaust gas in the exhaust passage enters the storage chamber from the introduction passage with the suit and the exhaust purification fuel as the exhaust pressure increases, the exhaust gas existing in the storage chamber is pushed along the meandering passage. It is. Exhaust gas existing in the vicinity of the outlet passage of the passage is pushed out and moves to the link chamber through the outlet passage. The phenomenon that the exhaust gas that has entered the storage chamber from the introduction path reaches the lead-out path with the suit and the fuel for exhaust purification and reaches the link chamber through the lead-out path is reliably suppressed.

  In the invention according to claim 7, in the invention according to any one of claims 2 to 6, it is assumed that the storage chamber, the introduction path, and the lead-out path are formed in the turbine housing.

  According to said structure, it becomes possible to form simultaneously a storage chamber, an introductory path, and an outlet path at the time of manufacture of a turbine housing. In addition, when the storage chamber, the introduction path and the lead-out path are formed by separate members outside the turbine housing, a space for arranging and attaching these members is required. By doing so, these spaces can be small.

(First embodiment)
Hereinafter, a first embodiment embodying the present invention will be described with reference to FIGS. FIG. 1 shows a configuration of a vehicular multi-cylinder diesel engine (hereinafter simply referred to as an engine) 11 to which the present embodiment is applied.

  The engine 11 is mainly configured to include an intake passage 12, a combustion chamber 13, and an exhaust passage 14. An air cleaner 15 that purifies the air sucked into the intake passage 12 is provided at the most upstream portion of the intake passage 12. In the engine 11, a turbocharger compressor wheel 17, an intercooler 18, and an intake throttle valve 19 are disposed in order from the air cleaner 15 toward the intake downstream side. The intake passage 12 is branched at an intake manifold 21 provided on the intake downstream side of the intake throttle valve 19, and is connected to a combustion chamber 13 for each cylinder of the engine 11 through this branched portion.

  The engine 11 is provided with a fuel injection valve 22 for injecting fuel to be used for combustion in the combustion chamber 13 for each cylinder. Each fuel injection valve 22 is connected to a common rail 23 that is a high-pressure fuel pipe for accumulating high-pressure fuel. The common rail 23 is supplied with high-pressure fuel discharged from a fuel pump (not shown).

On the other hand, the exhaust passage 14 is provided with an exhaust manifold 24 for collecting exhaust discharged from each combustion chamber 13 and a turbine wheel 25 of a turbocharger.
In such an engine 11, the air taken into the intake passage 12 is purified by the air cleaner 15 and then introduced into the compressor wheel 17 of the turbocharger. In the compressor wheel 17, the introduced air is compressed and discharged to the intercooler 18. The air that has become hot due to compression is cooled by the intercooler 18 and then distributed and supplied to the combustion chambers 13 for each cylinder via the intake throttle valve 19 and the intake manifold 21. The flow rate of air in the intake passage 12 is adjusted through opening control of the intake throttle valve 19.

  In the combustion chamber 13 where air is introduced, fuel is injected from the fuel injection valve 22. Then, the air-fuel mixture of the air introduced through the intake passage 12 and the fuel injected from the fuel injection valve 22 is burned in the combustion chamber 13. The piston (not shown) is reciprocated by the high-temperature and high-pressure combustion gas generated at this time, and the crankshaft 26 as the output shaft is rotated to obtain the driving force (output torque) of the engine 11.

  Exhaust gas generated by combustion in each combustion chamber 13 is introduced into a turbine wheel 25 of a turbocharger through an exhaust manifold 24. When the turbine wheel 25 is driven by the flow of the introduced exhaust, the compressor wheel 17 provided in the intake passage 12 is driven in conjunction with the compression of the air.

  Further, the engine 11 is provided with an exhaust purification device 27 for purifying exhaust exhausted from the engine 11. The exhaust purification device 27 includes an exhaust fuel addition valve 28 and also includes three catalytic converters (a first catalytic converter 31, a second catalytic converter 32, and a third catalytic converter 33) as exhaust purification catalysts. .

  The first catalytic converter 31 is disposed on the exhaust downstream side of the turbine wheel 25. The first catalytic converter 31 carries a NOx storage reduction catalyst. The NOx storage catalyst stores NOx in the exhaust gas, and stores NOx stored in the exhaust gas by injecting and supplying unburned fuel as a reducing agent. To reduce and purify. The second catalytic converter 32 is disposed on the exhaust downstream side of the first catalytic converter 31. The second catalytic converter 32 is formed of a porous material that allows the passage of gas components in the exhaust and prevents the passage of the particulate matter PM in the exhaust, and supports the NOx storage reduction catalyst. Yes. The third catalytic converter 33 is disposed on the exhaust downstream side of the second catalytic converter 32. The third catalytic converter 33 carries an oxidation catalyst that purifies the exhaust gas through oxidation of hydrocarbon HC and carbon monoxide CO in the exhaust gas.

  The exhaust fuel addition valve 28 is provided upstream of the turbine wheel 25 in the exhaust passage 14. The exhaust fuel addition valve 28 injects (adds) fuel supplied from the fuel pump into the exhaust gas as a reducing agent. With this added fuel (exhaust gas purification fuel), the exhaust gas is temporarily reduced to a reducing atmosphere, and nitrogen oxide NOx stored in the first catalytic converter 31 and the second catalytic converter 32 is reduced and purified. Further, the second catalytic converter 32 simultaneously performs the purification of the particulate matter PM.

  By the way, in this embodiment, the variable nozzle turbocharger 16 which has the variable nozzle mechanism 34 for adjusting the flow velocity of the exhaust gas sprayed on the turbine wheel 25 is used as said turbocharger. Next, a specific configuration of the variable nozzle turbocharger 16 will be described.

  As shown in FIGS. 2 and 3, the center housing 35 constituting the substantially central portion of the variable nozzle turbocharger 16 includes a main body portion 37 that rotatably supports the rotor shaft 36, and an outer peripheral portion of the main body portion 37. 2, flange portions 38 and 39 provided integrally on both sides in the direction (axial direction) along the axis L of the rotor shaft 36.

  The compressor wheel 17 and the turbine wheel 25 described above are attached to both ends of the rotor shaft 36. A compressor housing 42 is attached to the flange portion 38 of the center housing 35. An intake intake 43 is opened on the axis L of the compressor housing 42. In the compressor housing 42, a compressor passage 44 that extends in a spiral shape and communicates with the intake passage 12 is provided around the compressor wheel 17. Therefore, in the compressor housing 42, when the compressor wheel 17 rotates about the axis L based on the rotation of the rotor shaft 36, air is forcibly sent to the intake passage 12 through the intake intake 43 and the compressor passage 44 in order. .

  On the other hand, a turbine housing 45 is attached to the flange portion 39 of the center housing 35. An exhaust passage for guiding exhaust to the turbine wheel 25 is provided inside the turbine housing 45. The exhaust passage is configured to include a scroll passage 46 and a nozzle passage 47. The scroll passage 46 is formed in a spiral shape around the turbine wheel 25. The scroll passage 46 communicates with the exhaust passage 14 of the engine 11, and exhaust gas from the combustion chamber 13 is sent to the scroll passage 46 through the exhaust passage 14. The nozzle passage 47 is formed on the inner peripheral side of the scroll passage 46 and communicates between the scroll passage 46 and the turbine wheel 25. Therefore, the exhaust gas sent to the scroll passage 46 is blown to the turbine wheel 25 through the nozzle passage 47. By this spraying, the turbine wheel 25 rotates about the axis L. An exhaust discharge port 48 is opened on the axis L of the turbine housing 45, and the exhaust gas blown to the turbine wheel 25 is sent to the downstream side of the exhaust passage 14 through the exhaust discharge port 48.

  Next, the variable nozzle mechanism 34 for adjusting the flow velocity of the exhaust gas blown to the turbine wheel 25 will be described with reference to FIGS. 3 and 4. 4A shows a cross-sectional view of the variable nozzle mechanism 34, and FIG. 4B shows a side view of the variable nozzle mechanism 34.

  The variable nozzle mechanism 34 includes a nozzle back plate 51 formed in a ring shape. The nozzle back plate 51 is mounted on the main body portion 37 of the center housing 35 at a position spaced from the flange portion 39 toward the turbine wheel 25 side (left side in FIG. 3), and faces the nozzle passage 47. Yes. The nozzle back plate 51 is attached to the turbine housing 45 by fastening members (not shown) such as bolts.

  In the nozzle back plate 51, a plurality of shafts 52 are provided at equal angles with the circle center of the nozzle back plate 51 as the center. Each shaft 52 is rotatably supported by penetrating the nozzle back plate 51 in the thickness direction. A nozzle vane 53 is fixed as a variable nozzle at the end of each shaft 52 on the nozzle passage 47 side.

  The variable nozzle mechanism 34 is incorporated in the link chamber 54 and includes a link mechanism 55 for rotating the plurality of nozzle vanes 53 in synchronization. The link chamber 54 is provided on the opposite side (right side in FIG. 3) from the nozzle passage 47 with the nozzle back plate 51 interposed therebetween. The link chamber 54 is surrounded by the nozzle back plate 51, the turbine housing 45 and the center housing 35. In other words, the surfaces of these members constitute the wall surface of the link chamber 54.

  Next, the details of the link mechanism 55 will be described. The end of each shaft 52 opposite to the nozzle passage 47 (the right end in FIG. 3) is orthogonal to the coaxial 52 at the outer edge of the nozzle back plate 51. An open / close lever 56 extending toward the front is fixed. A pair of sandwiching portions 56 </ b> A that are bifurcated are formed at the tip of the opening / closing lever 56.

  On the other hand, a ring plate 57 is rotatably provided between the opening / closing lever 56 and the nozzle back plate 51 and coaxially with the nozzle back plate 51. The ring plate 57 is provided with a plurality of pins 58 at equal angles around the center of the circle, and these pins 58 are clamped by both clamping portions 56 </ b> A of the open / close levers 56. In this way, the plurality of nozzle vanes 53 and the ring plate 57 are connected by the shaft 52 and the opening / closing lever 56 for each nozzle vane 53.

  When the ring plate 57 is rotated around its center, each pin 58 pushes the clamping portion 56A of each opening / closing lever 56 in the rotation direction of the ring plate 57. As a result, the opening / closing levers 56 rotate the shaft 52, and the nozzle vanes 53 open and close in synchronization with each other about the coaxial 52 as the shaft 52 rotates.

  Further, the variable nozzle turbocharger 16 is provided with a drive mechanism for rotating the ring plate 57 to operate the link mechanism 55. Specifically, a pin 59 is provided on the outer edge (the lower end in FIG. 3) of the ring plate 57. On the other hand, a support shaft 61 is rotatably inserted into the flange portion 39 of the center housing 35, and a drive lever 62 is fixed to an end portion of the support shaft 61 on the link chamber 54 side (left side in FIG. 3). An operation piece 63 is fixed to the opposite end. A drive lever 62 is pivotally connected to the pin 59. In addition, an actuator 64 such as an electric motor is connected to the operation piece 63 (see FIG. 2).

  Therefore, when the operating piece 63 is operated by driving the actuator 64 to rotate the support shaft 61, the drive lever 62 rotates about the support shaft 61 as the support shaft 61 rotates. As a result, the ring plate 57 is pushed in the circumferential direction via the pin 59 by the drive lever 62 and rotates about the axis L. By the rotation of the ring plate 57, the gap between the adjacent nozzle vanes 53 becomes a size corresponding to the rotation angle (nozzle opening degree) of each nozzle vane 53, and the exhaust gas blown to the turbine wheel 25 through the gap. The flow rate of is adjusted. For example, when the nozzle vane 53 rotates to the closing side, the flow rate of the exhaust blown to the turbine wheel 25 increases. On the contrary, when the nozzle vane 53 rotates to the opening side, the flow velocity of the exhaust gas sprayed to the turbine wheel 25 becomes small.

  Further, by adjusting the flow rate of the exhaust gas blown to the turbine wheel 25, the rotational speeds of the turbine wheel 25, the rotor shaft 36, and the compressor wheel 17 are adjusted as appropriate, and the supercharging pressure is adjusted accordingly. By adjusting the supercharging pressure, it is possible to achieve both improvement in the output of the engine 11 and prevention of excessive pressure in the combustion chamber 13.

  By the way, in the variable nozzle turbocharger 16, there is a considerable gap 60 (see FIG. 3) between the members forming the link chamber 54 and mainly between the turbine housing 45 and the nozzle back plate 51. Therefore, when the exhaust pressure in the scroll passage 46 rises and becomes higher than the exhaust pressure in the link chamber 54, the exhaust passes through the gap 60 on the way from the scroll passage 46 to the turbine wheel 25 through the nozzle passage 47, and the link There is a risk of entering the chamber 54. When the exhaust gas includes a suit and exhaust purification fuel that is not sufficiently vaporized due to a low exhaust gas temperature, they may also pass through the gap 60 together with the exhaust gas and enter the link chamber 54.

  On the other hand, the wall surface of the link chamber 54 and the link mechanism 55 are lower than the temperature of the exhaust passage such as the scroll passage 46. The temperature of the exhaust gas in the link chamber 54 is low on the wall surface and the surface of the link mechanism 55 and increases as the distance from the wall surface and the link mechanism 55 increases. When there is such a temperature gradient, the exhaust purification fuel in the exhaust gas flowing into the link chamber 54 through the gap 60 adheres to the wall surface of the link chamber 54 and the link mechanism 55 by thermophoresis. Then, the suit in the exhaust adheres and accumulates at a location wetted by the fuel. In thermophoresis, particles suspended in a gas (exhaust gas) with a temperature gradient (exhaust gas for exhaust purification, suit) are more momentum from the gas molecules on the high temperature side than the gas molecules on the low temperature side. Therefore, the temperature gradient is a phenomenon of moving toward the low temperature side by receiving a force in the opposite direction. When the exhaust purification fuel adheres and the suit adheres and accumulates as described above, the deposits obstruct the movement of the link mechanism 55.

  Therefore, in the first embodiment, as shown in FIG. 5, the exhaust flow path and the link chamber 54 are communicated, and the communication for storing the exhaust gas flowing between the exhaust flow path and the link chamber 54 in accordance with the fluctuation of the exhaust pressure is stored. A passage 65 is provided. The communication path 65 includes a storage chamber 66, an introduction path 67, and a lead-out path 68.

  The storage chamber 66 is for temporarily storing the exhaust gas flowing between the exhaust passage and the link chamber 54 through the communication passage 65 in accordance with the fluctuation of the exhaust pressure. The storage chamber 66 is configured by an internal space of a tank 69 that is disposed at a position slightly away from the turbine housing 45 outward. Here, as the tank 69, a tank having an elongated rectangular cross section in the direction along the axis L (see FIG. 2) is used. The storage chamber 66 has a sufficiently large volume compared to the link chamber 54.

  The introduction path 67 is constituted by an internal space of an introduction pipe 71 that connects the storage chamber 66 and the scroll passage 46. Here, the end of the introduction pipe 71 on the storage chamber 66 side is fitted into the bottom of the tank 69 and opens at the inner bottom surface thereof. Further, the end portion of the introduction pipe 71 on the scroll passage 46 side is fitted into the wall portion of the turbine housing 45, and the turbine housing 45 opens on the inner wall surface on the outer peripheral side of the scroll passage 46. The introduction path 67 inside the introduction pipe 71 has a sufficiently large cross-sectional area as compared with the gap 60.

  The lead-out path 68 is configured by an internal space of a lead-out pipe 72 that connects the storage chamber 66 and the link chamber 54. Here, the end of the outlet pipe 72 on the side of the storage chamber 66 is fitted into the bottom of the tank 69 and opens at the inner bottom surface of the tank 69. Further, the end of the outlet pipe 72 on the scroll passage 46 side is fitted into the turbine housing 45, and is opened at a location facing the link chamber 54 on the inner wall surface of the turbine housing 45. The lead-out path 68 inside the lead-out pipe 72 has a sufficiently large cross-sectional area as compared with the gap 60 as in the case of the introduction path 67.

  In the variable nozzle turbocharger 16 configured as described above, when the exhaust pressure in the scroll passage 46 rises and becomes higher than the exhaust pressure in the link chamber 54, the variable nozzle turbocharger 16 tries to move to the link chamber 54. At this time, as a path through which the exhaust gas may pass, a gap 60 between the members (mainly the nozzle back plate 51 and the turbine housing 45) forming the link chamber 54 and the communication path 65 may be mentioned.

  Here, as described above, the cross-sectional areas of the introduction path 67 and the lead-out path 68 are sufficiently larger than the cross-sectional area of the gap 60. For this reason, when the exhaust pressure in the scroll passage 46 rises as described above, the exhaust gas flowing through the scroll passage 46 tends to flow into the communication passage 65 as compared with the gap 60.

  Further, when the exhaust gas flowing into the introduction passage 67 and the storage chamber 66 includes a suit and an exhaust purification fuel that is not sufficiently vaporized due to a low exhaust temperature, the suit and the exhaust purification fuel are also combined with the exhaust. It is easy to enter the introduction path 67 and the storage chamber 66. When the exhaust gas including the suit and the exhaust purification fuel enters the introduction passage 67 and the storage chamber 66, a part of the exhaust gas that has existed in the storage chamber 66 and the lead-out passage 68 until then enters the link chamber 54 through the lead-out passage 68. Extruded. Therefore, the exhaust gas containing the suit and the exhaust purification fuel and entering the storage chamber 66 from the scroll passage 46 through the introduction passage 67 is temporarily stored in the storage chamber 66 and is difficult to enter the link chamber 54.

Further, the amount of the suit and the exhaust purification fuel entering the link chamber 54 through the gap 60 is reduced by the amount entering the storage chamber 66 as described above.
In this way, the suit and exhaust purification fuel that enter the link chamber 54 from the scroll passage 46 together with the exhaust gas are reduced. Therefore, even if the wall surface of the link chamber 54 and the temperature of the link mechanism 55 are lower than the temperature of the scroll passage 46, the exhaust purifying fuel and the suit that adhere to and accumulate on the wall surface of the link chamber 54 and the link mechanism 55 by thermophoresis. The amount of decreases.

  On the other hand, when the exhaust pressure in the scroll passage 46 decreases and becomes lower than the exhaust pressure in the link chamber 54, a part of the exhaust in the link chamber 54 moves from the link chamber 54 to the storage chamber 66 through the outlet path 68. The exhaust containing the suit and the fuel for exhaust purification, which has entered before the pressure increase, is pushed back to the scroll passage 46.

According to the first embodiment described in detail above, the following effects can be obtained.
(1) The scroll passage 46 and the link chamber 54 are communicated with each other by a communication passage 65 including a storage chamber 66, an introduction passage 67, and an outlet passage 68. Therefore, when the exhaust pressure in the scroll passage 46 increases, the exhaust gas containing the suit and the exhaust purification fuel enters the storage chamber 66 through the introduction passage 67 from the scroll passage 46 and, at the same time, the storage chamber 66 until then. A part of the exhaust gas stored in the outlet can be pushed out from the outlet path 68 to the link chamber 54. The exhaust gas that has entered the storage chamber 66 can be temporarily stored in the storage chamber 66 so that it does not easily reach the link chamber 54.

  Further, a gap 60 between a plurality of members (mainly the turbine housing 45 and the nozzle back plate 51) forming the link chamber 54 is provided by the amount of the exhaust gas including the suit and the exhaust purification fuel entering the storage chamber 66 as described above. The suit and exhaust purification fuel that pass through the link chamber 54 can be reduced.

  In this way, the suit and exhaust purification fuel that enter the link chamber 54 from the scroll passage 46 together with the exhaust gas can be reduced. Therefore, it is possible to reduce the amount of exhaust purification fuel and suit adhering / depositing on the wall surface of the link chamber 54 and the link mechanism 55 by thermophoresis, and suppressing the problem that the operation of the link mechanism 55 is hindered by the deposit. it can.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG.
In the second embodiment, the end of the introduction passage 67 on the scroll passage 46 side protrudes from the inner wall surface of the turbine housing 45 into the scroll passage 46.

  Specifically, the introduction path 67 is configured by an internal space of an introduction pipe 71 that connects the storage chamber 66 and the scroll passage 46. The end of the introduction pipe 71 on the storage chamber 66 side is fitted into the bottom of the tank 69 and opens at the inner bottom surface. This is the same as in the first embodiment. However, the end portion of the introduction pipe 71 on the scroll passage 46 side passes through the wall portion of the turbine housing 45 and protrudes into the scroll passage 46. Therefore, the same end portion of the introduction pipe 71 opens in the scroll passage 46 instead of the inner wall surface on the outer peripheral side of the turbine housing 45. The second embodiment is greatly different from the first embodiment in this respect.

Since the configuration other than the above is the same as that of the first embodiment, the same members and portions as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.
In the variable nozzle turbocharger 16, the exhaust purification fuel contained in the exhaust gas may adhere to the inner wall surface of the turbine housing 45 that has been cooled by the outside air and cooled to a low temperature in the process of flowing through the scroll passage 46. At this time, if the end of the introduction pipe 71 on the scroll passage 46 side is opened at the inner wall surface of the turbine housing 45, the attached exhaust purification fuel may enter the introduction pipe 71 from this opening. In this regard, in the second embodiment, the end of the introduction pipe 71 on the exhaust flow path side protrudes from the inner wall surface of the turbine housing 45 into the scroll passage 46, and the same end of the introduction pipe 71 is inside the scroll passage 46. It is open. The protruding portion 71A of the introduction pipe 71 functions as a barrier, and restricts the exhaust purification fuel adhering to the inner wall surface from entering the introduction path 67 from the opening of the introduction pipe 71. Compared to the case where the introduction pipe 71 does not protrude and opens at the inner wall surface of the turbine housing 45, the exhaust purification fuel adhering to the inner wall surface is less likely to enter the introduction path 67.

Therefore, according to the second embodiment, in addition to the above (1), the following effects can be obtained.
(2) By projecting the end portion of the introduction pipe 71 from the inner wall surface of the turbine housing 45, the end surface is opened in the scroll passage 46. Therefore, even if the exhaust purification fuel adhering to the inner wall surface of the turbine housing 45 moves on the inner wall surface and approaches the introduction path 67, it is blocked by the protruding portion 71 </ b> A of the introduction pipe 71 and hardly enters the introduction path 67. can do. As a result, it is possible to further suppress the problem that the exhaust purification fuel enters the link chamber 54 through the introduction path 67, the storage chamber 66, and the outlet path 68.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG.
In the third embodiment, the end portion of the introduction path 67 on the storage chamber 66 side protrudes from the inner bottom surface of the tank 69 into the storage chamber 66. Specifically, the introduction path 67 is configured by an internal space of an introduction pipe 71 that connects the storage chamber 66 and the scroll passage 46. The end portion of the introduction pipe 71 on the scroll passage 46 side is fitted into the wall portion of the turbine housing 45, and opens on the inner wall surface on the outer peripheral side of the scroll passage 46. On the other hand, the end of the introduction pipe 71 on the storage chamber 66 side penetrates the bottom of the tank 69 and protrudes into the storage chamber 66. Therefore, the same end portion of the introduction pipe 71 is opened not in the inner bottom surface of the tank 69 but in the storage chamber 66.

  In the third embodiment, the end of the outlet channel 68 on the storage chamber 66 side protrudes from the inner bottom surface of the tank 69 into the storage chamber 66. Specifically, the lead-out path 68 is configured by an internal space of a lead-out pipe 72 that connects the storage chamber 66 and the link chamber 54. An end portion of the outlet pipe 72 on the link chamber 54 side is fitted into the turbine housing 45 and is opened in a wall surface constituting the link chamber 54. On the other hand, the end of the outlet pipe 72 on the storage chamber 66 side penetrates the bottom of the tank 69 and protrudes into the storage chamber 66. Therefore, the same end portion of the outlet pipe 72 opens in the storage chamber 66 instead of the inner bottom surface of the tank 69.

Since the configuration other than the above is the same as that of the first embodiment, the same members and portions as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.
In the variable nozzle turbocharger 16, the tank 69 is provided outside the turbine housing 45 and is cooled by the outside air so that the temperature is low. The storage chamber 66 has the lowest temperature on the wall surface, and the temperature increases as the distance from the wall surface increases. When the temperature gradient in the storage chamber 66 is large, the exhaust purification fuel in the exhaust adheres to the wall surface of the storage chamber 66 due to thermophoresis, and the suit in the exhaust adheres and accumulates at a location wetted by the fuel. There are concerns.

  If the end of the introduction pipe 71 on the side of the storage chamber 66 is open at the inner bottom surface of the storage chamber 66, the opening is closed or narrowed by the suit deposited as described above, and the introduction pipe 71 is introduced. There is a possibility that the flow of exhaust gas between the passage 67 and the storage chamber 66 may be hindered. Similarly, if the end of the outlet pipe 72 on the storage chamber 66 side is open at the inner bottom surface of the storage chamber 66, the opening is blocked or narrowed by the accumulated suit, and the outlet path 68 is reached. There is a risk that the flow of exhaust gas between the storage chamber 66 and the storage chamber 66 may be hindered.

  In this regard, in the third embodiment, each end of the introduction pipe 71 and the lead-out pipe 72 on the storage chamber 66 side protrudes from the inner bottom surface of the tank 69 to the inside. Due to these protrusions, the temperatures of the end portions of the introduction pipe 71 and the lead-out pipe 72 on the storage chamber 66 side, particularly the openings, are higher than the inner bottom surface of the storage chamber 66 described above. Therefore, it is difficult for the exhaust purification fuel to adhere to the suit and the suit to adhere and accumulate at each opening.

Therefore, according to the third embodiment, in addition to the above (1), the following effects can be obtained.
(3) By projecting the end of the introduction pipe 71 on the storage chamber 66 side from the inner bottom surface of the tank 69, the end face of the introduction pipe 71 is opened in the storage chamber 66. Therefore, it is difficult to cause the exhaust purification fuel and the suit from adhering to and depositing on the opening due to thermophoresis, and it is possible to suppress the flow of the exhaust from being hindered by the deposit between the introduction path 67 and the storage chamber 66. Can do.

  (4) By projecting the end of the outlet pipe 72 on the storage chamber 66 side from the inner bottom surface of the tank 69, the end face of the outlet pipe 72 is opened in the storage chamber 66. Therefore, it is possible to prevent the exhaust purification fuel from adhering to the opening and the suit from adhering to and accumulating in the opening, and the flow of the exhaust between the outlet path 68 and the storage chamber 66 can be suppressed.

(Fourth embodiment)
Next, a fourth embodiment embodying the present invention will be described with reference to FIG.
In the fourth embodiment, a plurality of partition members 73 and 74 are provided in the tank 69, and these partition members 73 and 74 allow the storage chamber 66 to have an opening of the introduction path 67 and an opening of the outlet path 68. A passage 75 is formed to connect the portions in a meandering state.

  Specifically, an introduction path 67 and a lead-out path 68 are connected to the inner bottom surface of the tank 69, and each end thereof is open. In the tank 69, a partition member 73 extending from the inner bottom surface toward the wall surface facing it is provided, and a partition member 74 extending from the opposite wall surface toward the inner bottom surface is provided. In the present embodiment, a pair of the former partition members 73 are provided between the openings on the inner bottom surface, while the latter partition member 74 is provided between the partition members 73 and 73 on the opposing wall surface. By arranging the plurality of partition members 73 and 74 in a staggered manner in this way, a passage 75 is formed in the tank 69 to connect the introduction passage 67 and the outlet passage 68 while meandering up and down.

Since the configuration other than the above is the same as that of the first embodiment, the same members and portions as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.
In the variable nozzle turbocharger 16, the exhaust passage 75 connecting the opening portion of the introduction passage 67 and the opening portion of the outlet passage 68 in the storage chamber 66 is meandering, so that the passage length is longer than that in the case of not meandering. become longer. Therefore, when the exhaust of the scroll passage 46 enters the storage chamber 66 from the introduction path 67 with the suit and the exhaust purification fuel as the exhaust pressure increases, the exhaust existing in the storage chamber 66 is It is pushed according to the meandering passage 75. Exhaust gas existing in the vicinity of the outlet path 68 of the passage 75 is pushed out and moves to the link chamber 54 through the outlet path 68.

Therefore, according to the fourth embodiment, in addition to the above (1), the following effects can be obtained.
(5) By providing a plurality of partition members 73 and 74 in the tank 69, a passage 75 is formed in the storage chamber 66 to connect the opening of the introduction path 67 and the opening of the outlet path 68 in a meandering state. Yes. Such a meandering passage 75 is longer than when the partition members 73 and 74 are not provided. Therefore, inconvenience that may occur when the passage length is short, that is, the exhaust gas that has entered the storage chamber 66 from the introduction passage 67 reaches the outlet passage 68 with the suit and the fuel for exhaust purification, and passes through the outlet passage 68. The phenomenon of reaching the link chamber 54 can be reliably suppressed.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to FIG.
In the fifth embodiment, the storage chamber 66, the introduction path 67, and the outlet path 68 are all formed in the turbine housing 45. More specifically, a storage chamber 66 is defined by a partition wall 76 in the turbine housing 45 and in the vicinity of the outer peripheral side of the scroll passage 46. A hole is formed in the partition wall 76, and an introduction path 67 that connects the scroll passage 46 and the storage chamber 66 is formed by the hole. In the turbine housing 45, a passage is provided on the outer peripheral side of the link chamber 54, and a lead-out path 68 that connects the storage chamber 66 and the link chamber 54 is configured by this passage. The storage chamber 66, the introduction path 67, and the outlet path 68 are all formed when the turbine housing 45 is manufactured. In the fifth embodiment, none of the tank 69, the introduction pipe 71 and the outlet pipe 72 used in the first to fourth embodiments is provided.

Since the configuration other than the above is the same as that of the first embodiment, the same members and portions as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.
In the variable nozzle turbocharger 16 configured as described above, the cross-sectional area of each of the introduction path 67 and the lead-out path 68 is sufficiently larger than the cross-sectional area of the gap 60, which increases the exhaust pressure in the scroll path 46. In this case, the exhaust gas flowing through the scroll passage 46 and containing the suit and the exhaust purification fuel tends to flow into the introduction path 67 through the gap 60.

  When the exhaust gas containing the suit and the exhaust purification fuel enters the introduction passage 67 and the storage chamber 66, a part of the exhaust gas that has existed in the storage chamber 66 and the discharge passage 68 until then passes through the discharge passage 68 to the link chamber 54. Extruded. Therefore, the exhaust gas containing the suit and the exhaust purification fuel and entering the storage chamber 66 from the scroll passage 46 through the introduction passage 67 is temporarily stored in the storage chamber 66 and is difficult to enter the link chamber 54.

Further, the amount of the suit and the exhaust purification fuel entering the link chamber 54 through the gap 60 is reduced by the amount entering the storage chamber 66 as described above.
In this way, the suit and exhaust purification fuel that enter the link chamber 54 from the scroll passage 46 together with the exhaust gas are reduced. Therefore, even if the wall surface of the link chamber 54 and the temperature of the link mechanism 55 are lower than the temperature of the scroll passage 46, the exhaust purifying fuel and the suit that adhere to and accumulate on the wall surface of the link chamber 54 and the link mechanism 55 by thermophoresis. And the operation of the link mechanism 55 is less likely to be hindered.

  When the exhaust pressure in the scroll passage 46 decreases, a part of the exhaust in the link chamber 54 moves from the link chamber 54 to the storage chamber 66 through the lead-out path 68, and the suit and exhaust that entered earlier when the pressure increased. Exhaust gas containing the purification fuel is pushed back into the scroll passage 46.

Therefore, according to the fifth embodiment, in addition to the above (1), the following effects can be obtained.
(6) The storage chamber 66, the introduction path 67 and the outlet path 68 are formed in the turbine housing 45. The storage chamber 66, the introduction path 67, and the outlet path 68 can be formed at the same time when the turbine housing 45 is manufactured. Therefore, the number of parts of the variable nozzle turbocharger 16 is reduced as compared with the case where the storage chamber 66, the introduction path 67, and the extraction path 68 are formed by the tank 69, the introduction pipe 71, and the outlet pipe 72. Accordingly, it is not necessary to manufacture or assemble the tank 69, the introduction pipe 71, and the outlet pipe 72, which is advantageous in reducing the production cost.

  Further, when the tank 69, the introduction pipe 71, and the lead-out pipe 72 are used, a space for arranging and attaching them is required outside the turbine housing 45. In the fifth embodiment, such a space is used. It's small. The increase in size of the variable nozzle turbocharger 16 due to the addition of the storage chamber 66, the introduction path 67, and the outlet path 68 can be suppressed.

Note that the present invention can be embodied in another embodiment described below.
In the second embodiment (see FIG. 6), as in the third embodiment, at least one of the end of the introduction pipe 71 on the storage chamber 66 side and the end of the outlet pipe 72 on the storage chamber 66 side is replaced with a tank 69. You may make it protrude in the storage chamber 66 from the inner bottom face. In this case, in addition to the effects of the second embodiment, the effects (3) and (4) of the third embodiment are obtained.

  Further, the partition members 73 and 74 as described in the fourth embodiment are provided in the tank 69 of the second embodiment, and the opening of the introduction path 67 and the opening of the outlet path 68 are meandered in the storage chamber 66. You may form the channel | path 75 connected in the state which carried out. In this case, in addition to the effect of the second embodiment, the effect (5) of the fourth embodiment is obtained.

  In the third embodiment (see FIG. 7), one of the end of the introduction pipe 71 on the storage chamber 66 side and the end of the lead-out pipe 72 on the storage chamber 66 side is not projected, and is opened at the inner bottom surface of the tank 69. You may let them.

  Further, the partition members 73 and 74 as described in the fourth embodiment are provided in the tank 69 in the third embodiment, and the opening of the introduction path 67 and the opening of the outlet path 68 meander in the storage chamber 66. You may form the channel | path 75 connected in the state which carried out. In this case, in addition to the effect of the third embodiment, the effect (5) in the fourth embodiment is obtained.

-You may change suitably the number of the partition members 73 and 74, arrangement | positioning aspect, etc. in 4th Embodiment (refer FIG. 8).
In the fifth embodiment (see FIG. 9), the introduction pipe 71 may be fixed to the partition wall 76 and the internal space may be used as the introduction path 67. In this case, the end of the introduction pipe 71 on the scroll passage 46 side may be protruded from the partition wall 76 into the scroll passage 46 as in the second embodiment. In this case, in addition to the effect of the fifth embodiment, the effect (2) of the second embodiment can be obtained.

  Further, the end portion of the introduction pipe 71 on the storage chamber 66 side may be protruded from the partition wall 76 into the storage chamber 66 as in the third embodiment. In this case, in addition to the effect of the fifth embodiment, the effect (3) in the third embodiment is obtained.

  Alternatively, the outlet pipe 72 may be fixed to the turbine housing 45 and the inner space thereof may be used as the outlet path 68. In this case, the end of the outlet pipe 72 on the storage chamber 66 side may be protruded from the inner wall surface of the turbine housing 45 into the storage chamber 66 as in the third embodiment. Thus, in addition to the effect of the fifth embodiment, the effect (4) in the third embodiment is obtained.

  -In 5th Embodiment, you may form the channel | path 75 which connects the opening part of the introductory path 67 and the opening part of the derivation | leading-out path 68 in the storage chamber 66 like the 4th Embodiment. In this case, in addition to the effect of the fifth embodiment, the effect (5) of the fourth embodiment is obtained.

  The present invention can also be applied to a diesel engine that performs so-called after-injection or post-injection, instead of supplying exhaust purification fuel from the exhaust fuel addition valve 28 (addition). After-injection (post-injection) is fuel that is performed during an expansion stroke or an exhaust stroke after fuel injection (pilot injection, main injection, etc.) is performed in the fuel injection valve 22 for combustion in the combustion chamber. It is a jet.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic which shows the structure of the diesel engine by which the variable nozzle turbocharger is mounted about 1st Embodiment which actualized this invention. Sectional drawing of the variable nozzle turbocharger in FIG. The elements on larger scale in FIG. (A) is sectional drawing of a variable nozzle mechanism, (B) is a side view. The fragmentary sectional view which shows the communicating path and its peripheral part in a variable nozzle turbocharger. The fragmentary sectional view which shows a communicating path and its peripheral part about the variable nozzle turbocharger of 2nd Embodiment which actualized this invention. The fragmentary sectional view which shows a communicating path and its peripheral part about the variable nozzle turbocharger of 3rd Embodiment which actualized this invention. The fragmentary sectional view which shows a communicating path and its peripheral part about the variable nozzle turbocharger of 4th Embodiment which actualized this invention. The fragmentary sectional view which shows a communicating path and its peripheral part about the variable nozzle turbocharger of 5th Embodiment which actualized this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Diesel engine, 16 ... Variable nozzle turbocharger, 25 ... Turbine wheel, 45 ... Turbine housing, 46 ... Scroll passage (a part of exhaust passage), 47 ... Nozzle passage (a part of exhaust passage) , 53 ... Nozzle vane (variable nozzle), 54 ... Link chamber, 55 ... Link mechanism, 65 ... Communication passage, 66 ... Storage chamber, 67 ... Introduction passage, 68 ... Outlet passage, 73, 74 ... Partition member, 75 ... Passage .

Claims (7)

Used for diesel engines that inject fuel to purify exhaust,
A turbine housing having an exhaust passage around the turbine wheel for directing exhaust to the turbine wheel;
A plurality of variable nozzles provided in the exhaust flow path;
A link mechanism provided in a link chamber surrounded by a plurality of members including the turbine housing and connected to the plurality of variable nozzles, and changing the opening degree of the plurality of variable nozzles through the link mechanism. By the variable nozzle turbocharger adapted to adjust the flow rate of the exhaust gas blown to the turbine wheel through the gap between adjacent variable nozzles,
A variable nozzle turbo, further comprising a communication path for communicating the exhaust flow path and the link chamber, and storing exhaust gas flowing between the exhaust flow path and the link chamber as the exhaust pressure varies. Charger. The communication path is
A storage chamber for storing exhaust gas flowing between the exhaust flow path and the link chamber through the communication passage in accordance with fluctuations in the exhaust pressure;
An introduction path connecting the exhaust flow path and the storage chamber;
The variable nozzle turbocharger according to claim 1, further comprising a lead-out path connecting the storage chamber and the link chamber. The variable nozzle turbocharger according to claim 2, wherein an end of the introduction path on the exhaust flow path side protrudes from an inner wall surface of the turbine housing into the exhaust flow path. The storage chamber is provided outside the turbine housing,
4. The variable nozzle turbocharger according to claim 2, wherein an end portion of the introduction path on the storage chamber side protrudes inward from a wall surface of the storage chamber. 5. The storage chamber is provided outside the turbine housing,
The variable nozzle turbocharger according to any one of claims 2 to 4, wherein an end of the lead-out path on the storage chamber side protrudes inward from a wall surface of the storage chamber. The partition member for forming the channel | path which connects the opening part of the said introductory channel in the said storage chamber and the opening part of the said outlet channel in the meandering state in the said storage chamber is provided. The variable nozzle turbocharger as described in any one. The variable nozzle turbocharger according to claim 2, wherein the storage chamber, the introduction path, and the lead-out path are formed in the turbine housing.

Images