JP6460028B2 - Turbocharged engine - Google Patents

Description

  The present invention relates to a turbocharged engine in which a turbocharger having at least two independent turbo units is attached to an engine body.

  In an engine with a turbocharger, a turbocharger that supercharges intake air using the exhaust energy of the engine is attached adjacent to one side wall of the engine body. An exhaust passage is provided in the housing of the turbocharger, and exhaust gas is supplied from the engine body to the exhaust passage. The exhaust passage includes an introduction passage that receives exhaust from the engine body, a turbine chamber that houses a turbine, and a scroll passage that guides the exhaust from the introduction passage to the turbine chamber. The introduced exhaust gas causes the turbine to rotate around the turbine shaft, rotate a blower fan of a compressor connected to the turbine shaft, and supercharge intake air.

  Conventionally, a turbocharger in which two independent turbo units are arranged in series in the exhaust path is known. For example, Patent Document 1 discloses a two-stage turbocharger that includes a large turbo unit that mainly operates in a medium to high speed rotation region of an engine and a small turbo unit that mainly operates in a low speed rotation region. Yes. The small turbine of the small turbo part is disposed upstream of the large turbine of the large turbo part in the exhaust passage. The exhaust passage includes a bypass passage that connects the introduction passage and the large turbine chamber without passing through the small turbine chamber. A regulating valve is disposed in the bypass passage, and the regulating valve is opened and closed in accordance with the engine rotation range.

Japanese Patent No. 5499953

  In a turbocharger, it is always required to efficiently transmit exhaust kinetic energy to a turbine to improve output and to make it as compact as possible. In the above-described two-stage turbocharger, the exhaust passage has a complicated structure, so it is difficult to satisfy these two requirements at a higher level.

  An object of the present invention is to provide a turbocharger capable of giving a large exhaust kinetic energy to a turbine and achieving a compact size in an engine provided with a turbocharger having at least two independent turbo parts. The purpose is to provide an aircraft engine.

An engine with a turbocharger according to one aspect of the present invention has an engine main body and an exhaust passage that is disposed adjacent to the engine main body and is supplied with exhaust from the engine main body, and is introduced into the engine main body. with a turbocharger for supercharging intake air that, the, the turbocharger, the first turbo unit which operates mainly the first turbine having a first turbine shaft in a high-speed rotation range of unrealized said engine body When the second turbine having a second turbine shaft and a second turbo unit which operates mainly in the low speed rotation range of unrealized the engine body, the exhaust passage, an introduction passage for receiving exhaust from the engine body the introduction passage includes a first upstream portion of the scroll start point that communicates with a first scroll passage for guiding the exhaust toward the first turbine, the second turbine and the first scan A turbo inter passage connecting the first upstream portion of the roll passage, a second upstream portion of the scroll start point that communicates with the introduction passage, and a second scroll passage for introducing the exhaust toward the second turbine, wherein A communication passage connecting the introduction passage and the second upstream portion of the second scroll passage; a passage bypassing the second scroll passage; and an upstream side of the communication passage and a first upstream portion of the first scroll passage An exhaust bypass valve, and an exhaust bypass valve is provided in the exhaust bypass passage, the exhaust bypass valve is a valve body that opens and closes the exhaust bypass passage, and a pivot that supports the valve body in a cantilevered manner. The rotary shaft is disposed on a side closer to the engine body than the valve body in one cross section orthogonal to the first turbine shaft, and the exhaust bypass. Closes the exhaust bypass passage in the low-speed rotation region, and opens the exhaust bypass passage in the high-speed rotation region, and the downstream end of the exhaust bypass passage and the downstream end of the inter-turbo passage are In a positional relationship included in one cross section, the first upstream portion merges, and the downstream end of the exhaust bypass passage is closer to the engine body than the downstream end of the inter-turbo passage And the exhaust bypass valve is disposed so that the valve body exists in the one cross section from the valve closing time to the valve opening time, and the first and second scroll passages are First and second upstream portions are respectively disposed on the far side of the engine body from the first and second turbine shafts, and downstream sides of the first and second upstream portions are respectively disposed on the engine body. The first , A passage scrolled so as to be closer to the second turbine shaft, wherein the first turbine rotates in a predetermined first rotation direction around the first turbine shaft, while the second turbine is the second turbine It rotates in the second rotation direction opposite to the first rotation direction around the turbine axis, and is downstream of the first turbo unit, the first scroll passage, the inter-turbo passage, and the exhaust bypass passage. and a side, and the exhaust bypass valve is accommodated in a first housing having a first flange portion, the second turbo unit, said second scroll passages, said introduction passage channel, said communication passage, said turbo passages between The upstream side and the upstream side of the exhaust bypass passage are housed in a second housing having a second flange portion fastened to the first flange portion .

  According to this turbocharged engine, the first and second upstream portions serving as the scroll start points of the first and second scroll passages are arranged on the side farther from the engine body than the first and second turbine shafts. Has been. For this reason, the layout of the exhaust passage from the introduction passage to the first and second upstream portions can be given a margin, and the exhaust passage can be prevented from being extremely curved. Therefore, the flow of the exhaust gas in the exhaust passage can be made smooth, and a large exhaust kinetic energy can be given to the first and second turbines. Further, the rotation directions of the first and second turbines are opposite to each other. If the exhaust passage is set on the assumption that both turbines rotate in the same direction, an exhaust passage that is greatly curved is inevitably required and the turbocharger is often increased in size, but the above configuration simplifies the exhaust passage. It becomes easy to design and can contribute to the compactness of the turbocharger.

  In the above turbocharged engine, it is preferable that the upstream side passage connected to the first upstream portion and the second upstream portion is an exhaust passage having a linear shape or a gently curved shape.

  According to this turbocharged engine, exhaust can be introduced into the first and second upstream portions of the first and second scroll passages without substantially giving resistance to the exhaust flow. Therefore, it becomes possible to give larger exhaust kinetic energy to the first and second turbines.

In the above engine with turbocharger, the second turbo unit, wherein disposed upstream of the first turbo unit in the exhaust passage, the exhaust passage is further pre Symbol second turbine and said first scroll include turbo between communication path connecting the first upstream portion of the passage, the portion that extends upstream from at least the second upstream portion of the communication passage, and, on the upstream side from at least the first upstream portion of the turbo inter passage It is desirable that the extending portion is the upstream passage that is continuous with the second upstream portion and the first upstream portion.

  According to the turbocharged engine, in the two-stage turbocharger in which the first turbo unit and the second turbo unit are arranged in series on the exhaust passage, the flow of exhaust toward the first and second turbines The exhaust kinetic energy can be increased by smoothing.

  In the engine with a turbocharger, it is preferable that the introduction passage is disposed between the first turbo part and the second turbo part.

  According to this turbocharged engine, the first and second upstream portions are arranged on the side farther from the engine body than the first and second turbine shafts, and the rotation directions of the first and second turbines In the configuration in which the directions are opposite to each other, the layout connecting the introduction passage with a smooth exhaust passage with a small degree of curvature is easily set compactly for both the first and second upstream portions.

  In the above turbocharged engine, the first turbo unit and the second turbo unit are arranged in a vertical direction, and the introduction passage is located between the first turbo unit and the second turbo unit. It is desirable that they are arranged in this position.

  According to this turbocharged engine, when the exhaust manifold is disposed on one side of the engine body, the turbocharger can be compactly disposed on the side.

  In the engine with a turbocharger, the first turbo unit is a large turbocharger that mainly operates in a medium to high-speed rotation range of the engine body, and the second turbo unit is the engine body. It is one of the preferred embodiments that the turbocharger is a small turbocharger that mainly operates in the low-speed rotation range.

  According to the present invention, in an engine equipped with a turbocharger having at least two independent turbo units, it is possible to give a large exhaust kinetic energy to the turbine and to make the turbocharger compact. A machine engine can be provided.

FIG. 1 is a perspective view of a turbocharged engine according to an embodiment of the present invention. FIG. 2 is a perspective view of the turbocharger portion of the engine, partly broken away. FIG. 3 is a diagram schematically showing the configuration of the turbocharged engine and its peripheral components, and the flow of intake and exhaust. FIG. 4 is a schematic cross-sectional view of the turbocharger according to the present embodiment. FIG. 5 is a perspective view showing an example of an exhaust bypass valve. FIG. 6 is a cross-sectional view showing the flow of exhaust in the turbocharger in the low speed rotation region of the engine body. FIG. 7 is a cross-sectional view showing an exhaust flow in the turbocharger in the medium speed and high speed rotation regions of the engine body.

[Schematic configuration of the engine]
Hereinafter, an engine with a turbocharger according to an embodiment of the present invention will be described in detail based on the drawings. First, a schematic configuration of the engine will be described. FIG. 1 is a perspective view of a turbocharger-equipped engine 1 according to an embodiment of the present invention, and FIG. 2 is a perspective view showing a part of the turbocharger 3 of the engine 1 with a part broken away. In FIG. 1, FIG. 2 and other drawings, front / rear, left / right and up / down direction indications are attached. This is for convenience of explanation and does not necessarily indicate the actual direction.

  The turbocharged engine 1 includes a multi-cylinder engine main body 10, an exhaust manifold 14 connected to the left side surface of the engine main body 10, an unillustrated intake manifold, and a left side of the engine main body 10. And a turbocharger 3 arranged. 1, the exhaust manifold 14 is surrounded by a manifold insulator 15, the left side surface of the engine body 10 is covered by an engine body insulator 16, and the turbocharger 3 is surrounded by a turbo insulator. 17 is covered.

  The engine body 10 is an in-line four-cylinder diesel engine, and includes a cylinder block 11, a cylinder head 12 attached to the upper surface of the cylinder block 11, and a cylinder head cover 13 disposed above the cylinder head 12. . The cylinder block 11 includes four cylinders 2 (one of which is shown in FIGS. 3 and 4 described later) that form a combustion chamber for fuel.

  The exhaust manifold 14 includes therein a manifold passage 141 (FIG. 4) that collects exhaust gas discharged from the exhaust port 25 of each cylinder 2 in one flow path. The inlet side of the exhaust manifold 14 is connected to the cylinder head 12, and the outlet side is connected to the turbocharger 3.

  The turbocharger 3 is a device that supercharges intake air introduced into the engine body 10 by using exhaust energy discharged from the engine body 10. The turbocharger 3 operates mainly in the medium to high speed rotation range of the engine body 10 to supercharge intake air, and the turbocharger 3A (first turbo unit) operates mainly in the low speed rotation range to intake air. And a small turbo part 3B (second turbo part). In the present embodiment, a small turbo unit 3B is continuously provided below the large turbo unit 3A. Each of the large turbo unit 3A and the small turbo unit 3B includes a turbine chamber disposed on the front side and a compressor chamber disposed on the rear side. In the turbocharger 3, an intake passage through which the exhaust gas is supplied from the engine main body 10 through the turbine chambers, and intake air through which the intake air introduced into the engine main body 10 passes through the compressor chambers. And a passage. That is, the turbine chambers are incorporated in the exhaust passage of the engine body 10, and the compressor chambers are incorporated in the intake passage of the engine body 10.

  FIG. 2 shows a large turbo housing 31 that partitions the large turbine chamber 33 (FIG. 3) of the large turbo section 3A and a small turbo housing 32 that partitions the small turbine chamber 35 (FIG. 3) of the small turbo section 3B. Has been. The large turbo housing 31 includes a sheet metal housing 311 made of a sheet metal case that defines a large scroll passage 55 and others described later, and a housing base 312 that supports the lower end of the sheet metal housing 311. An upper flange portion 313 is provided at the lower portion of the housing base 312.

  On the other hand, the small turbo housing 32 is a housing made of a cast iron case, and is integrally provided with an introduction flange portion 321 on the upstream side of the exhaust passage and a lower flange portion 322 on the downstream side. The introduction flange portion 321 is a flange portion for connecting to the exhaust manifold 14 and is a portion that serves as an exhaust inlet to the turbocharger 3. The lower flange portion 322 is a flange portion for connecting to the large turbo housing 31. The upper flange portion 313 is placed on the lower flange portion 322, and the large turbo housing 31 and the small turbo housing 32 are integrated by bolting them together. An exhaust flange 323 is provided at a portion serving as an exhaust outlet from the turbocharger 3. The exhaust side flange 323 is connected to the downstream side pipe of the exhaust passage.

  The manifold insulator 15 is an insulator that shields peripheral components from being damaged by heat generated by the exhaust manifold 14 through which high-temperature exhaust flows. The engine body insulator 16 protects the cylinder head cover 13, the harness, and the sensors from the heat generated from the exhaust manifold 14 and the turbocharger 3. The turbo insulator 17 is an insulator that covers the periphery of large and small turbo housings 31 and 32 through which high-temperature exhaust gas circulates and suppresses thermal damage to peripheral components.

[Internal structure of engine]
FIG. 3 is a diagram schematically showing the configuration of the turbocharged engine 1 and its peripheral components, and the flow of intake and exhaust. The engine 1 includes an engine body 10, an intake passage P1 for introducing combustion air into the engine body 10, an exhaust passage P2 for discharging combustion gas (exhaust gas) generated in the engine body 10, and the like. A turbocharger 3 having passages that respectively constitute part of the intake passage P1 and the exhaust passage P2, an exhaust purification device 70 disposed near the downstream end of the exhaust passage P2, an intake passage P1 and an exhaust passage P2. EGR (Exhaust Gas Recirculation) device 80 disposed between the two.

  Each cylinder 2 of the engine body 10 is provided with a piston 21, a combustion chamber 22, a crankshaft 23, an intake port 24, an exhaust port 25, an intake valve 26 and an exhaust valve 27. In FIG. 3, one cylinder 2 is shown. The piston 21 is accommodated in the cylinder 2 so as to be able to reciprocate. The combustion chamber 22 is formed above the piston 21 in the cylinder 2. Diesel fuel is injected into the combustion chamber 22 from an unillustrated injector. The fuel injected from the injector is mixed with the air supplied from the intake passage P <b> 1 and self-ignited in the combustion chamber 22. The piston 21 is pushed down by the expansion force due to the combustion and reciprocates in the vertical direction.

  The crankshaft 23 is an output shaft of the engine body 10 and is disposed below the piston 21. The piston 21 and the crankshaft 23 are connected to each other via a connecting rod. The crankshaft 23 rotates around its central axis according to the reciprocating motion of the piston 21. The intake port 24 is an opening through which air (intake air) supplied from the intake passage P <b> 1 is introduced into the cylinder 2. The exhaust port 25 is an opening for leading exhaust generated by the combustion of fuel in the cylinder 2 to the exhaust passage P2. The intake valve 26 is a valve that opens and closes the intake port 24, and the exhaust valve 27 is a valve that opens and closes the exhaust port 25.

  In the intake passage P1, an air cleaner 41, a compressor section (a large compressor chamber 34 and a small compressor chamber 36) of the turbocharger 3, an intercooler 42, and a throttle valve 43 are provided in this order from the upstream side of the intake flow. . The downstream end of the intake passage P1 is connected to the intake port 24 via an intake manifold (not shown). The air cleaner 41 purifies the air taken into the intake passage P1. The intercooler 42 cools the intake air sent to the combustion chamber 22 through the intake port 24. The throttle valve 43 is a valve that adjusts the amount of intake air sent to the combustion chamber 22. A blow-by recirculation passage 411 for sending blow-by gas to the combustion chamber 22 is connected to the upstream side of the turbocharger 3 in the intake passage P1. The intake air is supercharged when passing through the compressor section of the turbocharger 3 described in detail later.

  The upstream end of the exhaust passage P <b> 2 is connected to the exhaust port 25 via the exhaust manifold 14. The exhaust passage P2 is provided with the turbine section (the small turbine chamber 35 and the large turbine chamber 33) of the turbocharger 3 and the exhaust purification device 70 in order from the upstream side of the exhaust flow. The exhaust purification device 70 includes a catalyst device 71 including a NOx storage reduction catalyst that temporarily stores NOx in the exhaust and then reduces the NOx, and a DPF (Diesel Particulate Filter) 72 that collects particulate matter in the exhaust. . The kinetic energy of the exhaust gas is recovered when the exhaust gas passes through the turbine section of the turbocharger 3.

  The EGR device 80 is a device for recirculating a part of exhaust gas (EGR gas) discharged from the engine body 10 to intake air. The EGR device 80 includes a first EGR passage 81 and a second EGR passage 84 that allow the exhaust passage P2 and the intake passage P1 to communicate with each other, and a first EGR valve 82 and a second EGR valve 85 that open and close the passages 81 and 84, respectively. . An EGR cooler 83 is provided in the first EGR passage 81. The EGR gas is cooled by the EGR cooler 83 while passing through the first EGR passage 81 and then flows into the intake passage P1. On the other hand, the EGR cooler is not provided in the second EGR passage 84, and the EGR gas can flow into the intake passage P1 at a high temperature. The first and second EGR passages 81 and 84 communicate a portion of the exhaust passage P2 upstream of the turbocharger 3 and a portion of the intake passage P1 downstream of the throttle valve 43. Therefore, the exhaust before being introduced into the turbine part of the turbocharger 3 is supplied to the intake port 24 together with the intake air.

[Details of turbocharger]
Next, the internal structure of the turbocharger 3 according to the present embodiment will be described with reference to FIG. 3 described above and FIG. 4 showing a schematic cross section of the turbocharger 3. As described above, the turbocharger 3 includes the large turbo unit 3A for medium speed to high speed rotation region operation and the small turbo unit 3B for low speed rotation region operation. The large turbo unit 3 </ b> A includes a large turbine chamber 33 and a large compressor chamber 34. Similarly, the small turbo unit 3 </ b> B includes a small turbine chamber 35 and a small compressor chamber 36. The large turbine chamber 33 and the small turbine chamber 35 communicate with the exhaust passage P2, and the large compressor chamber 34 and the small compressor chamber 36 communicate with the intake passage P1.

  A large turbine 33T (first turbine) is accommodated in the large turbine chamber 33, and a large blower 34B is accommodated in the large compressor chamber 34, respectively. The large turbine 33T and the large blower 34B are connected by a large turbine shaft 37 (first turbine shaft). That is, the large turbine 33T is attached to one end of the large turbine shaft 37, and the large blower 34B is attached to the other end. The large turbine 33 </ b> T receives the exhaust flow (kinetic energy) and rotates around the large turbine shaft 37. The large blower 34B also rotates around the large turbine shaft 37 to compress (supercharge) the intake air. When the large turbine 33T rotates in response to exhaust kinetic energy, the large blower 34B also rotates integrally around the large turbine shaft 37.

  As the large turbine 33T, an impeller that has a plurality of blades and rotates around the large turbine shaft 37 when exhaust collides with the blades can be used. Also, as the large turbine 33T, a plurality of nozzle vanes whose angles can be changed are provided on the outer periphery of the turbine, and a VGT (Variable Geometry Turbine) capable of adjusting the flow velocity (that is, turbine capacity) of the exhaust gas flowing into the large turbine 33T according to the engine speed ) Is one of the preferred embodiments.

  The small turbine chamber 35 accommodates a small turbine 35T (second turbine), and the small compressor chamber 36 accommodates a small blower 36B. The small turbine 35T and the small blower 36B are connected by a small turbine shaft 38 (second turbine shaft). That is, the small turbine 35T is attached to one end of the small turbine shaft 38, and the small blower 36B is attached to the other end. The small turbine 35T receives the kinetic energy of the exhaust and rotates around the small turbine shaft 38. Similarly, the small blower 36B rotates around the small turbine shaft 38 to compress (supercharge) the intake air. When the small turbine 35T rotates in response to exhaust kinetic energy, the small blower 36B also rotates integrally around the small turbine shaft 38. As the small turbine 35T, a so-called FGT (Fixed Geometry Turbine) that cannot change the flow rate of the inflowing exhaust gas can be used.

  The capacity of the large turbine 33T is larger than the capacity of the small turbine 35T, and the capacity of the large blower 34B is set larger than the capacity of the small blower 36B. As a result, the large turbo unit 3A can rotate the large turbine 33T by exhaust gas having a larger flow rate than the small turbo unit 3B, and can supercharge intake air having a larger flow rate by rotation of the large blower 34B.

  The turbocharger 3 is provided with a supercharger intake passage 44 as a passage that serves as a part of the intake passage P1 within the turbocharger 3. The supercharger intake passage 44 includes an intake introduction passage 45, a first main passage 46, a second main passage 47, an outlet passage 48, and an intake bypass passage 49. The intake intake passage 45 is the most upstream intake passage in the turbocharger 3, and is a passage from the axial direction of the large turbine shaft 37 toward the large blower 34 </ b> B in the large compressor chamber 34. The first main passage 46 is a passage that guides intake air from the outer peripheral portion of the large blower 34B toward the axial center of the small blower 36B in the small compressor chamber 36. The second main passage 47 is a passage from the outer peripheral portion of the small blower 36 </ b> B toward the outlet passage 48. The outlet passage 48 is the most downstream intake passage in the turbocharger 3 and is a passage connected to the intercooler 42. Thus, the large blower 34B is disposed upstream of the small blower 36B in the intake air flow.

  The intake bypass passage 49 is a passage that bypasses the small compressor chamber 36, that is, a passage that guides intake air downstream without supplying intake air to the small blower 36B. Specifically, the intake bypass passage 49 branches from the middle of the first main passage 46 connecting the large compressor chamber 34 and the small compressor chamber 36, and joins the outlet passage 48 together with the second main passage 47. An intake bypass valve 491 that opens and closes the passage 49 is disposed in the intake bypass passage 49.

  In a state where the intake bypass valve 491 is fully closed and the intake bypass passage 49 is closed, the entire amount of intake air flows into the small compressor chamber 36. On the other hand, when the intake bypass valve 491 is open, most of the intake air bypasses the small compressor chamber 36 and flows downstream through the intake bypass passage 49. That is, since the small blower 36B accommodated in the small compressor chamber 36 becomes resistant to the flow of intake air, most of the intake air has a smaller resistance when the intake bypass valve 491 is open. It flows into the passage 49. The intake bypass valve 491 is opened and closed by a negative pressure type valve actuator 492.

  The turbocharger 3 is provided with a supercharger exhaust passage 50 as a passage serving as a part of the exhaust passage P2 in the turbocharger 3. The supercharger exhaust passage 50 includes an exhaust introduction passage 51 (introduction passage), a communication passage 52, a small scroll passage 53 (second scroll passage), a turbo passage 54, a large scroll passage 55 (first scroll passage), and a discharge passage. 56 and an exhaust bypass passage 57. As is clear from FIG. 4, the exhaust introduction passage 51, the communication passage 52 and the small scroll passage 53 are formed in the small turbo housing 32, and the large scroll passage 55 and the discharge passage 56 are formed in the large turbo housing 31. The passage, the inter-turbo passage 54 and the exhaust bypass passage 57 are passages formed across the housings 31 and 32. In the present embodiment, the small turbine 35T (that is, the small turbo part 3B) is disposed on the upstream side of the large turbine 33T (that is, the large turbo part 3A) in the exhaust passage P2.

  The exhaust introduction passage 51 is the most upstream exhaust passage in the turbocharger 3 and is a passage that receives exhaust from the engine body 10 side. The communication passage 52 is a passage that continues downstream of the exhaust introduction passage 51 and guides the exhaust toward the small turbine chamber 35. The small scroll passage 53 forms a part of the small turbine chamber 35, and is a passage that guides exhaust toward the small turbine 35T. The downstream end of the communication passage 52 is connected to the upstream portion 53U (second upstream portion) of the small scroll passage 53. The small scroll passage 53 is a spiral passage disposed so as to circulate around the outer periphery of the small turbine 35T, and the flow path width gradually decreases toward the downstream. The exhaust gas flows from the small scroll passage 53 toward the radial center of the small turbine 35T, and rotates the small turbine 35T around the small turbine shaft 38.

  The inter-turbo passage 54 is a passage connecting the small turbine 35T and the upstream portion 55U (first upstream portion) of the large scroll passage 55. The upstream portion of the inter-turbo passage 54 is a portion that extends from the small turbine chamber 35 in the axial direction of the small turbine 35T, and the downstream portion is a portion that continues to the upstream portion 55U. Exhaust gas that has flowed radially inward from the outer periphery of the small turbine 35T and has performed expansion work on the small turbine 35T is taken out from the inter-turbo passage 54 and travels toward the large turbine 33T.

  The large scroll passage 55 forms a part of the large turbine chamber 33, and is a passage that guides exhaust toward the large turbine 33T. The large scroll passage 55 is a spiral passage disposed so as to go around the outer periphery of the large turbine 33T, and the flow passage width gradually narrows toward the downstream. The exhaust gas flows from the large scroll passage 55 toward the radial center of the large turbine 33T, and rotates the large turbine 33T around the large turbine shaft 37. The exhaust passage 56 is the most downstream exhaust passage in the turbocharger 3, and extends from the large turbine chamber 33 in the axial direction of the large turbine 33T. Exhaust gas that has flowed radially inward from the outer periphery of the large turbine 33T and has performed expansion work on the large turbine 33T is taken out from the discharge passage 56. The downstream end of the discharge passage 56 is an opening provided in the exhaust-side flange portion 323 and is connected to the exhaust passage that reaches the downstream exhaust purification device 70.

  The exhaust bypass passage 57 is a passage that bypasses the small turbine chamber 35, that is, a passage that guides exhaust gas downstream (large turbine 33T) without causing exhaust to act on the small turbine 35T. Specifically, the exhaust bypass passage 57 branches from between the exhaust introduction passage 51 and the communication passage 52 and joins the upstream portion 55U of the large scroll passage 55, bypassing the small scroll passage 53 and the inter-turbo passage 54. doing. An exhaust bypass valve 6 that opens and closes the passage 47 is disposed in the exhaust bypass passage 57. The exhaust bypass valve 6 includes a valve body 61 that actually opens and closes the exhaust bypass passage 57, and a valve actuator 6A that operates the valve body 61.

  When the exhaust bypass valve 6 (valve body 61) is fully closed and the exhaust bypass passage 57 is closed, the entire amount of exhaust gas flows into the small turbine chamber 35. When the EGR device 80 is operated and the EGR gas is recirculated, the entire amount of the gas excluding the EGR gas from the exhaust discharged from the engine body 10 flows into the small turbine chamber 35. On the other hand, in a state where the exhaust bypass valve 6 is open, most of the exhaust gas bypasses the small turbine chamber 35 and flows into the large turbine chamber 33 (large scroll passage 55) on the downstream side. That is, since the small turbine 35T accommodated in the small turbine chamber 35 becomes resistant to the flow of exhaust, in the state where the exhaust bypass valve 6 is open, most of the exhaust is an exhaust bypass having a smaller resistance. It flows into the passage 57. That is, the exhaust gas flows downstream without passing through the small turbine 35T.

  In other words, no matter how the exhaust bypass valve 6 operates, the exhaust always passes through the large turbine 33T of the large turbine chamber 33. That is, since the large turbo unit 3A can always operate to perform supercharging of intake air, the supercharging pressure of intake air by the turbo supercharger 3 can be increased, and the energy efficiency of the entire engine system can be increased. .

  As a basic operation, the exhaust bypass valve 6 is fully closed when the engine body 10 is operating in the low speed rotation region, and exhaust is supplied to the small turbine 35T through the communication passage 52 and the small scroll passage 53. Since the inertia of the small turbine 35T is small, even if the exhaust flow rate is small, the rotational speed can be increased early, and the supercharging force by the small blower 36B can be increased. Thereafter, the exhaust gas passes through the inter-turbo passage 54 and the large scroll passage 55 and is supplied to the large turbine 33T. That is, in the low speed rotation region, both the large turbine 33T and the small turbine 35T rotate, and accordingly, the large blower 34B and the small blower 36B also rotate. Accordingly, both the large turbo unit 3A and the small turbo unit 3B operate and can supercharge intake air. Here, when VGT is attached to the large turbine 33T, it is desirable to increase the flow rate of the exhaust gas flowing into the large turbine 33T by reducing the opening degree of the VGT. Thereby, the supercharging force by the large blower 34B in a low speed rotation area can be increased.

  On the other hand, when the engine body 10 is operating in the medium speed to high speed rotation region, the exhaust bypass valve 6 is fully opened, and the exhaust is supplied exclusively to the large turbine 33T through the exhaust bypass passage 57. That is, since the exhaust flow resistance can be suppressed as much as possible and exhaust can be supplied to the large turbine 33T, energy efficiency can be improved. In addition, when the large turbine 33T has VGT, it is desirable that the VGT opening be a basic VGT opening for obtaining a predetermined supercharging pressure set in advance.

  The valve actuator 6A is composed of an electric actuator device. The valve actuator 6A can not only simply open and close the valve body 61 but also adjust the opening degree of the valve body 61 between fully closed and fully opened. The opening degree of the valve body 61 is set so that the supercharging pressure becomes a target pressure for each operating condition. The target boost pressure and the opening degree of the valve body 61 are set in advance by the engine speed and the engine load. The valve actuator 6A controls the opening degree of the valve body 61 according to the setting.

[Details of exhaust passage in turbocharger]
Next, a specific arrangement relationship of the supercharger exhaust passage 50 in the turbocharger 3 and the shape of the passage will be described in detail mainly with reference to FIG. First, the exhaust introduction passage 51 is a passage having an opening at the end face of the introduction flange portion 321 and extending leftward. The exhaust introduction passage 51 is disposed between the large turbo part 3A and the small turbo part 3B. Specifically, the large turbo unit 3A and the small turbo unit 3B are arranged in the vertical direction, and the exhaust introduction passage 51 is arranged at an intermediate height position between the turbo units 3A and 3B.

  An exhaust opening of an exhaust port 25 is provided on the left side surface of the engine body 10 (cylinder head 12). The exhaust manifold 14 has an inlet side flange portion 142 on the right end side and an outlet side flange portion 143 on the left end side. The flange portions 142 and 143 are provided with openings on the left and right ends of the manifold passage 141. ing. The inlet side flange portion 142 is coupled to the cylinder head 12 in alignment with the outlet opening of the exhaust port 25. The outlet side flange portion 143 is coupled to the introduction flange portion 321. As a result, the exhaust port 25 and the exhaust introduction passage 51 (supercharger exhaust passage 50) are in communication with each other via the manifold passage 141, and the exhaust from the engine body 10 side is turbocharged as indicated by an arrow F in FIG. It can be taken into the supercharger 3.

  Between the exhaust introduction passage 51, the upstream portion 53 </ b> U of the small scroll passage 53 and the upstream portion 55 </ b> U of the large scroll passage 55, a Y-shaped branch passage 50 </ b> B that connects these is disposed. The upstream portions 53U and 55U are scroll start points where the scroll passages 53 and 55 start to vortex toward the axis of each turbine 33T and 35T. Of the branch passage 50B, a passage that extends downward from the downstream end of the exhaust introduction passage 51 and connects to the upstream portion 53U is a communication passage 52, and a passage that extends upward from the downstream end and connects to the upstream portion 55U is an exhaust bypass passage 57. is there.

  The small scroll passage 53 is a passage that scrolls counterclockwise in FIG. 4, while the large scroll passage 55 is a passage that scrolls clockwise. That is, the directions in which the scroll passages 53 and 55 are swirled are set in opposite directions. This is because the upstream portions 53U and 55U of the scroll passages 53 and 55 are arranged as follows.

  In the small scroll passage 53, the upstream portion 53U is disposed on the side (left side) farther than the small turbine shaft 38 with respect to the left side surface of the engine body 10, and the portion of the small scroll passage 53 spiraling from the upstream portion 53U toward the downstream side is small turbine. It is a passage scrolled so as to be closer to the side closer to the engine body 10 (right side) than the shaft 38. An upstream portion 53U of the small scroll passage 53 opens upward. The small scroll passage 53 extends from the upstream portion 53U in the lower right direction, passes through the lower side of the small turbine shaft 38, and thereafter passes through the right side of the small turbine shaft 38 and moves upward. Of course, the downstream end of the small scroll passage 53 that circulates around the small turbine 35T is located on the left side of the small turbine shaft 38.

  Similarly, in the large scroll passage 55, the upstream portion 55U is disposed on the side (left side) farther than the large turbine shaft 37 with respect to the left side surface of the engine body 10, and a portion spiraling from the upstream portion 55U toward the downstream side is provided. This is a passage scrolled so as to be closer to the engine body 10 (right side) than the large turbine shaft 37. The upstream portion 55U of the large scroll passage 55 opens downward. The large scroll passage 55 is directed upward from the upstream portion 55U, passes through the upper side of the first turbine shaft 37, and thereafter passes through the right side of the large turbine shaft 37 and travels downward. Of course, the downstream end of the large scroll passage 55 that circulates around the large turbine 33 </ b> T is located on the left side of the large turbine shaft 37.

  Thus, the small scroll passage 53 and the small scroll passage 55 are arranged such that the upstream portions 53U and 55U face each other in the vertical direction. Further, the exhaust introduction passage 51 is located between the upstream portions 53U and 55U. Therefore, it is possible to connect the scroll passages 53 and 55 to the exhaust introduction passage 51 by the Y-shaped compact branch passage 50B.

  Further, since the scroll passages 53 and 55 are swirled in opposite directions, the rotation direction of the small turbine 35T and the rotation direction of the large turbine 33T are also opposite. That is, the small turbine 35T rotates in the counterclockwise direction (predetermined first rotation direction) around the small turbine shaft 38 along the scroll direction of the small scroll passage 53 in the cross section shown in FIG. On the other hand, the large turbine 33T rotates in the clockwise direction (second rotation direction) around the axis of the large turbine shaft 37 along the scroll direction of the large scroll passage 55.

  Furthermore, the arrangement of the large and small scroll passages 53 and 55 enables the upstream passages connected to the upstream portions 53U and 55U to be straight or gently curved exhaust passages. As shown in FIG. 4, the upstream passage 53UA, which is a portion extending from at least the upstream portion 53U to the upstream side of the communication passage 52, is a passage that extends downward substantially linearly. Further, the upstream-side passage 55UA, which is a portion extending from at least the upstream portion 55U to the upstream side of the inter-turbo passage 54, is also a passage that extends upward in a substantially linear shape. Therefore, the exhaust gas can enter the upstream portions 53U and 55U of the large and small scroll passages 53 and 55 along the linear route with little flow resistance.

  The inter-turbo passage 54 extends from the arrangement position of the small turbine 35T in the axial direction of the small turbine 35T, changes its path in the upper left direction, and has the substantially straight upstream passage 55UA (near the downstream of the inter-turbo passage 54). And the upstream portion 53U of the large scroll passage 55. As described above, the exhaust bypass passage 57 is also an exhaust passage connected to the upstream portion 53U. The arrangement relationship between the two is such that the inter-turbo passage 54 is arranged farther from the left side surface of the engine body 10 than the exhaust bypass passage 57.

  As described above, the upstream portion 53U is disposed on the far side of the large turbine shaft 37 with respect to the left side surface of the engine body 10. The downstream end 54E of the inter-turbo passage 54 and the downstream end 57E of the exhaust bypass passage 57 are joined to the upstream portion 53U. The positional relationship between the downstream end 57E and the downstream end 54E is greater than that of the downstream end 54E. There is a relationship facing the upstream portion 53U on the side closer to the main body 10.

  Thus, the exhaust bypass passage 57 and its downstream end 57E are disposed closer to the engine body 10 that discharges the exhaust than the inter-turbo passage 54 and its downstream end 54E. It becomes easy to set the exhaust bypass passage 57 that connects the portion 53U in a short circuit as an exhaust passage that is short and has a small degree of curvature.

  On the other hand, such an arrangement relationship is a layout in which the upstream-side passage 55UA of the upstream portion 53U in the inter-turbo passage 54 can be easily set in a linear shape or a gentle curved shape. That is, by disposing the exhaust bypass passage 57 on the side closer to the engine body 10, it is easy to take a space below the upstream portion 53U that opens downward. Further, in the present embodiment, the small turbine shaft 38 is disposed closer to the left side of the engine body 10 than the large turbine shaft 37, and the diameter of the small turbine 35T is small. It is easy to make an empty space. Therefore, it is easy to set the upstream passage 55UA, which is the downstream portion of the inter-turbo passage 54, in a substantially linear shape by using the space below the upstream portion 53U.

  Note that disposing the small turbine shaft 38 closer to the engine body 10 also contributes to setting the communication passage 52 in a substantially linear shape. By arranging the small turbine shaft 38 to the right of the large turbine shaft 37, it becomes easy to take a space to the left of the small scroll passage 53. Combined with the fact that the upstream portion 53U is located to the left of the small turbine shaft 38, and the diameter of the small scroll passage 53 is smaller than the diameter of the large scroll passage 55, the left space has a suitable width. it can. Therefore, by using this left space, the upstream passage 53UA can be joined to the upstream portion 53U by making the upstream passage 53UA substantially straight in the communication passage 52 branched downward from the exhaust introduction passage 51 extending to the left.

[Exhaust flow]
Next, the exhaust flow in the turbocharger 3 will be described in relation to the operating state of the exhaust bypass valve 6 with further reference to FIGS. FIG. 5 is a perspective view showing an example of the exhaust bypass valve 6. The exhaust bypass valve 6 includes a valve main body 61, a holding piece 62, and a rotating shaft 63. The valve body 61 opens and closes the exhaust bypass passage 57 as described above, and has a shape capable of closing the exhaust bypass passage 57, that is, a size larger than the opening size of the downstream end of the exhaust bypass passage 57. ing. The holding piece 62 is a rectangular member disposed on the back surface of the valve main body 61, and holds the valve main body 61 on one end side thereof. The rotating shaft 63 extends in a direction (front-rear direction) substantially parallel to the large turbine shaft 37 and is coupled to the other end side of the holding piece 62. The rotation shaft 63 can be rotated around its axis by the valve actuator 6A.

  The rotating shaft 63 cantilever-supports the valve body 61 via a holding piece 62. Accordingly, when the rotation shaft 63 rotates about the axis, the valve body 61 also rotates about the rotation shaft 63 as an axis. When the valve actuator 6A rotates the rotation shaft 63 about the axis, the valve main body 61 is between the posture (FIG. 6) closing the exhaust bypass passage 57 and the posture opening the exhaust bypass passage 57 (FIG. 7). Change the posture with.

  Here, the rotation shaft 63 is disposed on the right side of the exhaust bypass passage 57, that is, on the side closer to the engine body 10 in the cross section (FIG. 4) orthogonal to the large turbine shaft 37. This is because it is easy to change the posture of the valve main body 61 from the closed posture to the open posture without going against the flow of exhaust flowing into the upstream portion 55U of the large scroll passage 55 from the exhaust bypass passage 57. Another reason is that the valve body 61 in the open posture is unlikely to become an exhaust flow resistance.

  FIG. 6 is a cross-sectional view showing the flow of exhaust in the turbocharger 3 in the low-speed rotation region of the engine body 10. In the low speed rotation region, the valve actuator 6A closes the valve body 61 and the exhaust bypass passage 57 is closed. In this case, the exhaust (arrow F) discharged from the engine body 10 side enters the exhaust introduction passage 51 provided in the small turbo housing 32 of the turbocharger 3. The exhaust is guided downward by the communication passage 52 and reaches the upstream portion 53U of the small scroll passage 53 (arrow F1). Then, the exhaust gas flows from the small scroll passage 53 on the outer peripheral portion of the small turbine 35T toward the small turbine shaft 38 in order to act on the small turbine 35T, and rotates the small turbine 35T in the counterclockwise direction R2.

  Thereafter, the exhaust is led out from the axial direction of the small turbine 35T and enters the inter-turbo passage 54. The exhaust gas is guided upward along the inter-turbo passage 54 and reaches the upstream portion 55U of the large scroll passage 55 via the upstream passage 55UA (arrow F2). At this time, the exhaust gas also flows from the small turbo housing 32 into the large turbo housing 31. Then, the exhaust gas flows in the direction from the large scroll passage 55 on the outer peripheral portion of the large turbine 33T toward the large turbine shaft 37 to act on the large turbine 33T, and rotates the large turbine 33T in the clockwise direction R1. Thereafter, the exhaust gas is led out from the axial direction of the large turbine 33T, discharged to the outside of the turbocharger 3 through the discharge passage 56 (FIG. 3), and directed to the exhaust gas purification device 70.

  FIG. 7 is a cross-sectional view showing an exhaust flow in the turbocharger 3 in the medium speed and high speed rotation regions of the engine body 10. In the middle speed to high speed rotation range, the valve actuator 6A opens the valve body 61 and the exhaust bypass passage 57 is opened. In this case, the exhaust (arrow F) discharged from the engine body 10 side flows exclusively through the exhaust introduction passage 51 and into the exhaust bypass passage 57 having a low flow resistance. Then, the exhaust gas is guided to the upper left along the exhaust bypass passage 57 and flows into the upstream portion 55U of the large scroll passage 55 from the right side (arrow F3). At this time, the exhaust gas also flows from the small turbo housing 32 into the large turbo housing 31. Similarly, the exhaust gas flows into the large turbine 33T from the large scroll passage 55, is led out from the axial direction of the large turbine 33T, and travels toward the discharge passage 56.

[Function and effect]
The turbocharged engine 1 according to this embodiment described above has the following operational effects. In the turbocharged engine 1, the upstream portion 53 </ b> U serving as the scroll starting point of the small scroll passage 53 is disposed on the side farther from the engine body 10 than the small turbine shaft 38, and the scroll starting point of the large scroll passage 55 is provided. The upstream portion 55 </ b> U to be arranged has a structure arranged on the side farther from the engine body 10 than the large turbine shaft 37. For this reason, the layout of the exhaust passages (the communication passage 52 and the inter-turbo passage 54) from the exhaust introduction passage 51 to the respective upstream portions 53U and 55U can be provided with a margin, and the exhaust passages can be prevented from being extremely curved. . Therefore, the flow of the exhaust gas in the exhaust passage can be made smooth, and a large exhaust kinetic energy can be given to the turbines 33T and 35T.

  The small scroll passage 53 and the large scroll passage 55 are passages scrolled so that the downstream sides of the upstream portions 53U and 55U are closer to the engine body 10 than the turbine shafts 38 and 37, and are in opposite directions. Scroll to For this reason, the large turbine 33T and the small turbine 35T rotate in directions opposite to each other. If the exhaust passage is set on the assumption that both turbines 33T and 35T are rotated in the same direction, an exhaust passage that is greatly curved is inevitably required, and the turbocharger 3 tends to be enlarged. In the existing two-stage turbocharger, since it is assumed that two turbines rotate in the same direction, it is generally difficult to reduce the size of the turbocharger 3. However, according to the structure of this embodiment, it becomes easy to design the exhaust path in the turbocharger 3 simply, and the turbocharger 3 can be made compact.

  The upstream-side passage 53UA and the upstream-side passage 55UA that are respectively connected to the upstream portion 53U of the small scroll passage 53 and the upstream portion 55U of the large scroll passage 55 are substantially straight exhaust passages. For this reason, exhaust can be introduced into each of the upstream portions 53U and 55U without substantially giving resistance to the flow of exhaust. Therefore, larger exhaust kinetic energy can be given to the large turbine 33T and the small turbine 35T.

  In particular, the turbocharger 3 of the present embodiment is a two-stage turbocharger in which a large turbo section 3A is arranged in series downstream of the small turbo section 3B on the supercharger exhaust passage 50. In such a turbocharger, the upstream side passage 53UA corresponding to the downstream portion of the communication passage 52 and the upstream side passage 55UA corresponding to the downstream portion of the inter-turbo passage 54 are made substantially linear, so that the large turbine 33T and The exhaust kinetic energy can be increased by smoothing the flow of exhaust toward the small turbine 35T.

  An exhaust introduction passage 51 that receives exhaust from the engine body 10 is disposed between the large turbo part 3A and the small turbo part 3B. Specifically, the exhaust manifold 14 is disposed on one side of the engine body 10, the large turbo part 3 </ b> A and the small turbo part 3 </ b> B are disposed in the vertical direction, and are connected to the exhaust manifold 14 at an intermediate height position between them. An exhaust introduction passage 51 is disposed.

  Accordingly, the upstream portions 53U and 55U of the large and small scroll passages 53 and 55 are arranged on the side farther from the engine body 10 than the turbine shafts 37 and 38, and the large and small turbines 33T and 35T rotate. In the configuration in which the directions are opposite to each other, the layout connecting the exhaust introduction passage 51 with a smooth exhaust passage with a small degree of curvature can be set compactly for both of the upstream portions 53U and 55U.

  As described above, according to the turbocharged engine 1 of the present embodiment, in the engine to which the turbocharger 3 having at least two independent turbo parts (the large turbo part 3A and the small turbo part 3B) is attached. The large and small turbines 33T and 35T can be given large exhaust kinetic energy, and the turbocharger 3 can be made compact.

[Description of Modified Embodiment]
Although one embodiment of the present invention has been described above, the present invention is not limited to this. For example, in the above-described embodiment, the example in which the first turbo unit and the second turbo unit are the large turbo unit 3A and the small turbo unit 3B is shown. Alternatively, the first and second turbo units may be turbo units having the same turbine capacity. Moreover, in the said embodiment, the large turbo part 3A was shown in the example arrange | positioned in series downstream of the small turbo part 3B. The first and second turbo units may be connected to the exhaust introduction passage 51 in parallel.

  In the said embodiment, the aspect with which large turbo part 3A was arrange | positioned on the small turbo part 3B was illustrated. The first and second turbo units are not limited to being arranged in the vertical direction, but may be arranged in a horizontal direction or an oblique direction. Further, as long as the first and second turbo units satisfy the conditions of the present invention, other turbo units may be provided.

1 Engine with turbocharger 10 Engine body 3 Turbocharger 3A Large turbo part (1st turbo part)
3B Small turbo part (second turbo part)
31 Large turbo housing 32 Small turbo housing 33T Large turbine (first turbine)
35T small turbine (second turbine)
37 Large turbine shaft (first turbine shaft)
38 Small turbine shaft (second turbine shaft)
50 Supercharger exhaust passage 51 Exhaust introduction passage (introduction passage)
52 Communication passage 53 Small scroll passage (second scroll passage)
53U upstream part (second upstream part)
53UA upstream passage 54 turbo passage 55 large scroll passage (first scroll passage)
55U upstream part (first upstream part)
55UA Upstream passage 56 Discharge passage 57 Exhaust bypass passage 6 Exhaust bypass valve P1 Intake passage P2 Exhaust passage

Claims (6)

The engine body,
A turbocharger disposed adjacent to the engine body, having an exhaust passage through which exhaust is supplied from the engine body, and supercharging intake air introduced into the engine body,
The turbocharger includes a first turbo unit which operates mainly the first turbine having a first turbine shaft in a high-speed rotation range of unrealized said engine body, a second turbine unrealized said having a second turbine shaft Including a second turbo unit that mainly operates in a low-speed rotation region of the engine body ,
The exhaust passage is
An introduction passage for receiving exhaust from the engine body side;
A first scroll passage having a first upstream portion as a scroll start point portion communicating with the introduction passage, and leading exhaust toward the first turbine;
An inter-turbo passage connecting the second turbine and the first upstream portion of the first scroll passage;
A second scroll passage having a second upstream portion as a scroll starting point portion communicating with the introduction passage, and leading exhaust toward the second turbine;
A communication passage connecting the introduction passage and the second upstream portion of the second scroll passage;
An exhaust bypass passage that bypasses the second scroll passage and connects an upstream side of the communication passage and a first upstream portion of the first scroll passage;
The exhaust bypass passage is provided with an exhaust bypass valve, and the exhaust bypass valve includes a valve body that opens and closes the exhaust bypass passage, and a pivot shaft that cantilever-supports the valve body. In one cross section orthogonal to the first turbine shaft, the exhaust bypass valve is disposed closer to the engine body than the valve body, and the exhaust bypass valve closes the exhaust bypass passage in the low speed rotation region. , Opening the exhaust bypass passage in the high-speed rotation region,
A downstream end of the exhaust bypass passage and a downstream end of the inter-turbo passage join the first upstream portion in a positional relationship included in the one cross section, and are downstream ends of the exhaust bypass passage Is disposed closer to the engine body than the downstream end of the inter-turbo passage, and the exhaust bypass valve is located within the one section from the time of closing to the time of opening. Arranged to exist in
In the first and second scroll passages, the first and second upstream portions are disposed on the far side of the engine body from the first and second turbine shafts, respectively, and the first and second upstream portions Each of which is a passage scrolled so that the downstream side of each part is directed to a side closer to the engine body than the first and second turbine shafts,
The first turbine rotates around the first turbine axis in a predetermined first rotation direction, while the second turbine rotates around the second turbine axis in a second rotation direction opposite to the first rotation direction. Is what
The first turbo unit, the first scroll passage, the downstream side of the inter-turbo passage and the downstream side of the exhaust bypass passage, and the exhaust bypass valve are housed in a first housing having a first flange portion,
The second flange portion, the second scroll portion, the second scroll passage, the introduction passage, the communication passage, the upstream side of the inter-turbo passage and the upstream side of the exhaust bypass passage are fastened to the first flange portion. An engine with a turbocharger , housed in a second housing comprising In the turbocharged engine according to claim 1,
The turbocharged engine, wherein the upstream passage connected to the first upstream portion and the second upstream portion is an exhaust passage that is linear or gently curved. The turbocharged engine according to claim 2,
The second turbo part is disposed upstream of the first turbo part in the exhaust passage;
The exhaust passage further includes an inter-turbo passage that connects the second turbine and a first upstream portion of the first scroll passage,
At least a portion extending from the second upstream portion to the upstream side of the communication passage and a portion extending from the first upstream portion to the upstream side of the inter-turbo passage are at the second upstream portion and the first upstream portion. An engine with a turbocharger, which is the upstream side passage. The turbocharged engine according to any one of claims 1 to 3,
The introduction passage is an engine with a turbocharger, which is disposed between the first turbo part and the second turbo part. The turbocharged engine according to claim 4,
The first turbo part and the second turbo part are arranged in a vertical direction,
The turbocharged engine, wherein the introduction passage is disposed at a height position between the first turbo part and the second turbo part. In the turbocharged engine according to any one of claims 1 to 5,
Wherein the first turbo unit is a large-turbocharged unit,
The second turbo unit is a small type turbocharged unit, engine turbocharged.

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