JP5350823B2 - Exhaust passage structure of internal combustion engine - Google Patents

Description

  The present invention relates to an exhaust passage structure for an internal combustion engine.

  In an internal combustion engine, for example, a two-cycle uniflow type diesel engine, one exhaust valve (hereinafter referred to as a main valve) is incorporated in an exhaust valve box, and the main valve is opened and closed, and combustion is performed in an exhaust receiver (exhaust collecting portion). While exhausting gas (exhaust gas), scavenging is also performed. This scavenging is performed by introducing scavenging from a scavenging port provided on the inner wall of the cylinder liner. Further, the exhaust valve box is provided with a sub valve different from the main valve, and a high temperature chamber and a low temperature chamber separated through the sub valve.

  Then, at the initial opening of the main valve (the initial stage of exhaust), high pressure and high temperature combustion gas is introduced from the cylinder into the high temperature chamber, and is discharged from the high temperature chamber to the exhaust receiver (external) through the high temperature exhaust passage. In addition, the remaining combustion gas in the cylinder is introduced into the low temperature chamber during the period from the middle opening to the closing of the main valve (from the middle to the latter), and is discharged from the low temperature chamber through the low temperature exhaust passage. (For example, see Patent Document 1).

  As an exhaust passage structure of an internal combustion engine, there has been proposed an exhaust purification device for an internal combustion engine in which accumulation due to adhesion of manganese oxide to the rectifying plate is eliminated and clogging of the rectifying plate is prevented (for example, patent document) 2). An internal combustion engine having an exhaust receiver that can effectively suppress vibration in an internal combustion engine with a large-sized low-pressure turbocharge has been proposed (see, for example, Patent Document 3).

Japanese Utility Model Publication No. 02-145617 (FIG. 1) JP 2007-182786 A (page 3-4, FIG. 1) JP 07-317558 A (page 4, FIG. 2)

  However, the structure of the exhaust passage of the conventional exhaust valve box is formed, for example, in a cross-sectional shape as shown in FIG. The combustion gas introduced into the high temperature chamber 6 from the cylinder through the exhaust port 5a of the exhaust valve box 5 is not particularly accompanied by swirl (swirl flow) for the initial stage of exhaust, and the center of the outlet 7a of the high temperature exhaust passage 7 With respect to the center line L connecting the center of the high temperature chamber 6 and the center line L, as shown by the arrows, it is discharged as a substantially symmetrical flow and flows to the high temperature exhaust passage 7. In FIG. 4, the length of the stream line indicating the flow of the combustion gas indicates the flow velocity at that position.

  Here, the combustion gas discharged from the high temperature chamber 6 hits the inner wall surface 6a of the high temperature chamber 6 at a portion on the opposite side to the outlet 7a of the high temperature exhaust passage 7, and a part of the combustion gas stays in a reflux state. Smooth flow is hindered. Moreover, in the site | part by the side of the exit 7a of the high temperature exhaust passage 7 of the high temperature chamber 6, a vortex is formed in a part of combustion gas discharged | emitted from the high temperature chamber 6, and a smooth flow is also inhibited.

  For this reason, the flow of the combustion gas flowing into the high temperature chamber 6 and the high temperature chamber 6 into the high temperature exhaust passage 7 is deteriorated. As a result, there is a problem that the combustion gas having a flow rate corresponding to the minimum cross-sectional area of the high-temperature exhaust passage 7 cannot be discharged, and the exhaust efficiency is extremely poor.

  Further, in each of the above Patent Documents 1 and 2, there is no disclosure about an invention in which the exhaust valve is opened and closed, and the combustion gas is discharged from the high temperature chamber to one exhaust receiver (exhaust collecting portion) through the high temperature exhaust passage. It has not been.

  The present invention has been made to solve such problems, and facilitates the flow of the combustion gas in the high temperature chamber and the high temperature exhaust passage in the exhaust valve box for discharging the high temperature combustion gas to the exhaust receiver. Therefore, an object of the present invention is to provide an exhaust passage structure for an internal combustion engine in which exhaust efficiency is remarkably increased.

  In order to solve the above-mentioned problems, the means employed by the present invention includes a main valve for exhausting combustion gas in the cylinder, and a high-temperature exhaust valve provided in the exhaust valve box and discharged from the cylinder through the main valve. A high-temperature chamber that introduces combustion gas, a high-temperature exhaust passage that is provided in the exhaust valve box and discharges the combustion gas in the high-temperature chamber to the outside, and is provided in the exhaust valve box and is discharged from the cylinder through the main valve. In an exhaust passage structure of an internal combustion engine comprising a low-temperature exhaust passage for discharging low-temperature combustion gas to the outside, and a sub valve provided in the exhaust valve box for switching the flow of combustion gas to the high-temperature exhaust passage and the low-temperature exhaust passage A rectifying plate is provided on the inner wall surface of the high temperature chamber for smoothly guiding the high temperature combustion gas introduced into the high temperature chamber to the high temperature exhaust passage.

  In the present invention, the high-temperature combustion gas discharged from the cylinder at the initial stage of opening of the main valve is introduced into the high-temperature chamber and discharged from the high-temperature chamber to the outside through the high-temperature exhaust passage. Here, the rectifying plate newly provided on the inner wall surface of the high temperature chamber smoothly flows the combustion gas discharged from the cylinder and introduced into the high temperature chamber into the high temperature exhaust passage without stagnation. As a result, the flow of the combustion gas in the high temperature chamber and the high temperature exhaust passage becomes uniform, and as a result, the average flow velocity becomes faster, and the combustion gas having a flow rate corresponding to the minimum cross-sectional area of the high temperature exhaust passage can be discharged smoothly. It becomes like this.

  In the exhaust passage structure of the internal combustion engine, the rectifying plate is preferably formed of a first rectifying plate provided on the opposite side to the outlet side of the high temperature exhaust passage and toward the center of the outlet side.

  Thus, by providing the first rectifying plate on the inner wall surface of the high temperature chamber opposite to the outlet side of the high temperature exhaust passage and toward the center of the outlet side, the combustion gas introduced from the cylinder into the high temperature chamber can be reduced. It can be divided substantially equally on both sides of the first rectifying plate and flow along the inner wall surface of the high temperature chamber, and the interference and stagnation of the combustion gas at the portion can be effectively prevented. Thereby, the flow of combustion gas becomes very smooth.

  In the exhaust passage structure of the internal combustion engine, the rectifying plate is preferably composed of a second rectifying plate provided on the outlet side of the high-temperature exhaust passage and toward the center of the outlet side.

  Thus, by providing the second rectifying plate on the outlet side of the high-temperature exhaust passage on the inner wall surface of the high-temperature chamber and toward the center of the outlet side, the combustion gas introduced from the cylinder is allowed to flow out of the second rectifying plate. It is possible to divide the gas into the high-temperature exhaust passage approximately equally on both sides, and effectively prevent the combustion gas from interfering with or staying at that portion. Thereby, the flow of combustion gas becomes very smooth.

  In the exhaust passage structure of the internal combustion engine, the first rectifying plate spreads so as to form an arc-shaped concave curved surface from the tip of both side surfaces toward the center of the outlet side of the high temperature exhaust passage toward the inner wall surface of the high temperature chamber. It is desirable that

In this way, both side surfaces of the first rectifying plate provided in the high temperature chamber are widened so as to form an arc-shaped concave curved surface from the tip toward the center of the outlet side of the high temperature exhaust passage toward the inner wall surface of the high temperature chamber. The combustion gas introduced into the high temperature chamber can be made to flow smoothly toward the inner wall surface of the high temperature chamber substantially evenly on both sides along the concave curved surface, thereby further smoothing the flow of the combustion gas. Can do.

  In the exhaust passage structure of the internal combustion engine, the second rectifying plate has an arc-shaped concave curved surface from a tip facing both sides to the center of the outlet side of the high temperature exhaust passage toward the inner wall surface of the high temperature chamber. It is desirable to spread.

  In this way, both side surfaces of the second rectifying plate provided in the high temperature chamber are widened so as to form an arc-shaped concave curved surface from the tip toward the center of the outlet side of the high temperature exhaust passage toward the inner wall surface of the high temperature chamber. Thus, the combustion gas discharged from the high temperature chamber is made to flow substantially evenly on both sides along the concave curved surface so that it flows smoothly into the high temperature exhaust passage. Thereby, the flow of combustion gas can be made smoother.

  In the exhaust passage structure of the internal combustion engine, it is desirable to provide a bulging portion in which the inner wall surface in the vicinity of the inlet of the high temperature chamber bulges in a convex curved surface in the high temperature chamber.

  In the vicinity of the entrance of the high greenhouse, vortices are easily formed in the combustion gas introduced from the cylinder into the high temperature chamber along the inner wall surface. However, in this way, by providing a bulging portion in the high temperature chamber in which the inner wall surface in the vicinity of the inlet of the high temperature chamber forms a convex curved surface, the combustion gas from the cylinder is near the inlet of the high temperature chamber. The gas flows along the inner wall of the high greenhouse, and the combustion gas introduced from the cylinder flows smoothly into the high temperature chamber and into the high temperature exhaust passage.

  In the exhaust passage structure of the internal combustion engine, it is desirable that the bulging portion is formed in an annular shape so as to surround the inlet of the high temperature chamber. In this way, by forming the bulging portion in an annular shape so as to surround the inlet of the high temperature chamber, the smoothening of the flow of combustion gas by the bulging portion can be further enhanced.

  In the exhaust passage structure of the internal combustion engine, the tip of the rectifying member having a substantially inverted conical shape attached to the support member that supports the valve stem of the subvalve is reduced in diameter so as to form an arcuate concave curved surface. It is desirable to extend to the valve side.

  In this way, the tip of the rectifying member attached to the support member that supports the valve stem of the auxiliary valve is formed to extend toward the main valve side by forming an arcuate concave curved surface, so that the combustion gas from the cylinder is heated to a high temperature. It is possible to smoothly guide into the room and into the high-temperature exhaust passage, and the flow of the combustion gas can be further smoothed.

  In the exhaust passage structure of the internal combustion engine, the arcuate concave portion corresponding to the convex curved surface of the bulging portion is formed at the tip of the rectifying member having a substantially inverted conical shape attached to the support member that supports the valve stem of the sub valve. It is desirable to reduce the diameter so as to form a curved surface and to extend to the main valve side so that the tip portion of the rectifying member and the bulging portion of the high temperature chamber cooperate.

  Further, in the exhaust passage structure of the internal combustion engine, the tip of the rectifying member having a substantially inverted conical shape attached to the support member that supports the valve stem of the subvalve is reduced in diameter so as to form an arcuate concave curved surface. It is desirable to form the main valve so as to face the bulging portion of the high temperature chamber when the sub valve is operated to open the high temperature chamber.

In this way, the bulging part of the high temperature chamber is formed as a concave curved surface corresponding to the convex curved surface of the bulging part provided in the high temperature exhaust passage with the tip of the rectifying member attached to the support member supporting the valve stem of the sub valve. And the auxiliary valve is formed so as to face the bulging portion of the high temperature chamber when the auxiliary valve is operated to open the high temperature chamber, thereby further increasing the shape of the exhaust passage. It becomes smooth and the combustion gas from the cylinder can be more smoothly guided to the high temperature chamber and the high temperature exhaust passage.

  As described above in detail, the exhaust passage structure of the internal combustion engine of the present invention is provided with a main valve for exhausting the combustion gas in the cylinder and the exhaust valve box, and is discharged from the cylinder through the main valve. A high-temperature chamber for introducing high-temperature combustion gas, a high-temperature exhaust passage that is provided in the exhaust valve box and discharges the combustion gas in the high-temperature chamber to the outside, and is provided in the exhaust valve box and discharged from the cylinder through the main valve An exhaust passage for an internal combustion engine comprising a low-temperature exhaust passage for discharging the generated low-temperature combustion gas to the outside, and a sub valve provided in the exhaust valve box for switching the flow of the combustion gas to the high-temperature exhaust passage and the low-temperature exhaust passage In the structure, a rectifying plate for smoothly guiding the high-temperature combustion gas introduced into the high-temperature chamber to the high-temperature exhaust passage is provided on the inner wall surface of the high-temperature chamber.

  Therefore, the flow of combustion gas in the high-temperature chamber and high-temperature exhaust passage for discharging high-temperature combustion gas to the outside becomes uniform, resulting in a faster average flow velocity, and combustion at a flow rate commensurate with the minimum cross-sectional area of the high-temperature exhaust passage. Gas can be discharged smoothly. That is, there is an excellent effect that the flow of the combustion gas in the high temperature chamber and the high temperature exhaust passage becomes extremely smooth, and the exhaust efficiency of the internal combustion engine can be remarkably increased.

It is principal part sectional drawing of the exhaust valve box of the diesel engine to which the exhaust passage structure of the internal combustion engine which concerns on one Embodiment of this invention is applied. It is principal part sectional drawing in alignment with the arrow II-II of the exhaust valve box shown in FIG. It is explanatory drawing which showed typically the flow of the combustion gas in the high temperature chamber and high temperature exhaust passage which were shown in FIG. It is explanatory drawing which showed typically the flow of the combustion gas in the high temperature chamber and high temperature exhaust passage in the conventional exhaust passage structure.

  A mode for carrying out the invention of an exhaust passage structure for an internal combustion engine according to the present invention will be described in detail with reference to FIGS.

  FIG. 1 is a sectional view of an essential part of an exhaust valve box to which an exhaust passage structure for an internal combustion engine according to the present invention is applied. As shown in FIG. 1, the exhaust valve box 11 is mounted on the valve seat 2 of the cylinder block 1, and the main valve 21, the high temperature chamber 12 of the exhaust valve box 11, and the high temperature exhaust passage 13 communicating with the high temperature chamber 12. A low-temperature chamber 14 (low-temperature exhaust passage), and a low-temperature exhaust passage 15 communicating with the low-temperature chamber 14. Further, the high-temperature chamber 12 and the high-temperature exhaust passage 13 side, and the low-temperature chamber 14 and the low-temperature exhaust passage 15 side. And a sub valve 25 for switching the flow of the combustion gas.

  Further, a hydraulic cylinder (not shown) that opens the main valve 21, a plurality of, for example, three hydraulic cylinders 31 that are provided in the hydraulic cylinder block 30 and perform the switching operation of the sub valve 25, and the main valve 21 An air piston (not shown) that is fixed to the upper portion of the valve stem 22 to perform the recovery operation of the main valve 21, and an air piston 29 that is fixed to the upper portion of the valve stem 26 of the subvalve 25 to perform the recovery operation of the subvalve 25. The casing includes a casing 35 that houses an air piston of the main valve 21 and an air piston 29 of the sub-valve 25 and forms an air spring chamber 36 for applying air pressure.

  As an example, the exhaust valve box 11 is applied to a two-cycle uniflow diesel engine. In this two-cycle uniflow type diesel engine, there is a scavenging port on the side wall of the cylinder liner, and the main valve 21 performs exhaust and scavenging.

  The valve opening operation of the main valve 21 is performed by pushing the valve stem 22 downward in the figure by the hydraulic cylinder that is operated by high pressure oil pressure. The valve closing operation (recovery operation) is performed by the air piston attached to the valve stem 22 pulling up the valve stem 22 upward in the drawing. That is, the air pressure in the air spring chamber 36 formed below the air piston is the operating source for the valve closing operation of the main valve 21.

  The switching operation of the sub valve 25 is performed by operating a plurality of hydraulic cylinders 31 provided in the hydraulic cylinder block 30 by high pressure oil pressure to push the air piston 29 upward in the drawing. Further, the recovery operation is performed by releasing the hydraulic pressure of the hydraulic cylinder 31 and pushing the valve stem 26 downward in the figure by the air piston 29. That is, the air pressure in the air spring chamber 36 formed above the air piston 29 serves as an operating source for the recovery operation of the sub valve 25.

  The sub-valve 25 has a right cylindrical shape, and its outer diameter is slightly smaller than the exhaust port 11a of the exhaust valve box 11, and its inner diameter is substantially the same as the exhaust port 2a of the valve seat 2. The exhaust port 11 a of the exhaust valve box 11 has a larger diameter than the exhaust port 2 a of the valve seat 2. The sub-valve 25 has an inner peripheral surface connected to the outer peripheral surface of the valve stem 26 by a plurality of plate-like radii (spokes) 25a. And the combustion gas discharged | emitted from the cylinder 3 is discharged | emitted in the high temperature chamber 12 through between these radiation 25a.

  The auxiliary valve 25 has a skirt portion 25b formed at the tip thereof. The skirt portion 25b has a truncated conical cylindrical shape (conical truncated cone shape) in which the outer diameter of the rear end is larger than the outer diameter of the front end. The outer diameter of the front end is slightly smaller than the exhaust port 11a of the exhaust valve box 11, and the outer peripheral surface of the rear end can be slidably contacted with the inner peripheral surface of the exhaust port 11a of the exhaust valve box 11. And the front-end | tip of the subvalve 25 which makes a right cylindrical shape is provided in a row by the substantially center part of the internal peripheral surface of the skirt part 25b.

  When the auxiliary valve 25 is restored by the air piston 29 and switched to the position shown in the figure, the skirt portion 25b is inserted into the exhaust port 11a of the exhaust valve box 11, and the outer peripheral surface of the rear end is the exhaust port 11a. It is in sliding contact with the inner peripheral surface and communicates with the cylinder 3 through the exhaust port 2 a of the valve seat 2. The auxiliary valve 25 allows the cylinder 3 and the high temperature chamber 12 to communicate with each other and closes the low temperature chamber 14.

  The auxiliary valve 25 is held at the position shown in the initial stage when the main valve 21 starts to open (the initial stage of exhaust), and discharges the high-temperature and high-pressure combustion gas in the cylinder 3 to the high-temperature chamber 12, and the high-temperature chamber 12 The exhaust gas is discharged to the exhaust passage 13 and switched to the low temperature chamber 14 side after the middle of the valve opening, and the remaining combustion gas (scavenging) in the cylinder 3 is discharged to the low temperature chamber 14 and the low temperature exhaust passage 15.

  As shown in FIG. 2, the high temperature chamber 12 is formed in a substantially symmetric shape with respect to a center line L connecting the center of the outlet 13 a of the high temperature exhaust passage 13 and the center O of the exhaust port 11 a and the high temperature chamber 12. The high temperature chamber 12 is provided with rectifying plates 17 and 18 for smoothing the flow of the combustion gas discharged from the cylinder 3 through the main valve 21.

  As shown in FIG. 1, the rectifying plates 17, 18 are arranged along the axial direction (vertical direction in the drawing) of the high temperature chamber 12, that is, along the discharge direction of the combustion gas discharged from the cylinder 3 and high temperature exhaust. On the center line L of the passage 13, it is formed in the direction of the outlet 13 a of the high temperature exhaust passage 13.

  The rectifying plate 17 is a first rectifying plate, and is disposed on the inner wall surface 12a of the high temperature chamber 12 and on the side opposite to the outlet 13a of the high temperature exhaust passage 13, and as shown in FIG. It is formed over almost the entire height. The rectifying plate 18 is a second rectifying plate, on the outlet 13 a side of the high temperature exhaust passage 13 of the high temperature chamber 12, as shown in FIG. 1, near the approximate center height of the high temperature chamber 12 from the upper wall surface of the high temperature chamber 12. Until it is drooping.

  As shown in FIG. 2, the inner wall surface 12a of the high temperature chamber 12 is opposite to the outlet 13a side of the high temperature exhaust passage 13 on the inner side of the cylinder 3, more specifically the exhaust valve box 11, compared to the outlet 13a side. Therefore, the height of the current plate 17 (the length of the high-temperature exhaust passage 13 in the direction of the center line L) cannot be increased (lengthened).

  For this reason, the rectifying plate 17 is formed lower than the rectifying plate 18 (the length of the high-temperature exhaust passage 13 in the direction of the center line L) is approximately half of the rectifying plate 18. The rectifying plate 18 is formed higher than the rectifying plate 17 toward the outlet 13a side of the high-temperature exhaust passage 13 (longer in the direction of the outlet 13a along the center line L).

  The rectifying plate 17 is formed such that both side surfaces 17a extend from the tip toward the inner wall surface 12a of the high temperature chamber 12 so as to form, for example, an arcuate concave curved surface having a radius of curvature R1. Similarly, the rectifying plate 18 is formed such that both side surfaces 18a extend from the tip toward the inner wall surface 12a of the high temperature chamber 12 so as to form, for example, an arc-shaped concave curved surface having a curvature radius R2.

  Thus, by forming the both side surfaces 17a, 18a of the rectifying plates 17, 18 so as to spread from the tip toward the inner wall surface 12a of the high temperature chamber 12 with an arc-shaped concave curved surface, the high temperature chamber 12 from the cylinder 3 is formed. This makes it possible to make the flow of the combustion gas discharged smoothly. Moreover, the internal diameter of the high temperature chamber 12 is larger than the internal diameter of the high temperature exhaust passage 13, and the connecting portions 13c and 13d between the high temperature chamber 12 and the inlet of the high temperature exhaust passage 13 are smooth curved surfaces.

  For example, when the inner diameter of the outlet 13a of the high-temperature exhaust passage 13 is D0, the diameter of the valve face (valve contact surface) 21a of the main valve 21 shown in FIG. The radius of curvature R1 of the side surface 17a is about 0.2 to 0.5 times the passage outlet diameter D0, and the radius of curvature R2 of the side surface 18a of the rectifying plate 18 is about 0.3 to 1.0 times the passage outlet diameter D0. It is said to be about. The ratio D1 / Dv between the passage inner diameter D1 of the auxiliary valve 25 and the diameter Dv of the valve face (valve contact surface) 21a of the main valve 21 is about 0.9 to 1.2.

  As shown in FIG. 1, the lower inner wall surface 12 a in the vicinity of the inlet 12 c of the high temperature chamber 12 bulges upward in the drawing to form a convex curved surface, and a bulging portion 12 b is formed in the high temperature chamber 12. . The bulging portion 12b is desirably formed in an annular shape so as to surround the inlet 12c of the high temperature chamber 12. However, the bulging portion 12b does not necessarily have an annular shape so as to surround the entire inlet 12c. For example, the bulging portion 12b may be formed only on the lower inner wall surface 12a in the drawing on the high temperature exhaust passage 13 side.

  Further, a rectifying member 27 having a substantially inverted conical shape is provided at the lower end portion of the hydraulic cylinder block 30 that penetrates and supports the valve stem 26 of the sub-valve 25, and the tip portion 27a of the rectifying member 27 has a high temperature. The outer surface of the chamber 12 facing the bulging portion 12b is a concave curved surface portion 27b having an arcuate concave curved surface corresponding to the convex curved surface of the bulging portion 12b. It extends to the 21 side.

  A bulging portion 12b having a convex curved surface is provided on the lower inner wall surface 12a in the vicinity of the entrance 12c of the high greenhouse 12, and a convex curved surface of the bulging portion 12b is provided at the tip portion 27a of the rectifying member 27 facing the bulging portion. By providing the corresponding concave curved surface portion 27b, the bulging portion 12b of the high temperature chamber 12 and the tip end portion 27a of the rectifying member 27 cooperate with each other, and the combustion gas is transferred from the cylinder 3 to the high temperature chamber 12 by their interaction. The air is smoothly discharged into the high-temperature exhaust passage 13.

FIG. 3 shows an example of the flow of combustion gas in the high temperature chamber 12 and the high temperature exhaust passage 13 shown in FIG. Combustion gas discharged from the cylinder 3 into the high temperature chamber 12 through the discharge port 11a of the exhaust valve box 11 is interfered by flowing substantially equally on the left and right along both side surfaces 17a forming the concave curved surface of the rectifying plate 17. Is prevented, and further flows along the inner wall surface 12 a of the high temperature chamber 12 toward the high temperature exhaust passage 13.

  The combustion gas discharged from between the rectifying plate 17 and the rectifying plate 18 flows toward the high temperature exhaust passage 13 along the inner wall surface 12 a of the high temperature chamber 12. Further, the combustion gas discharged from the vicinity of the rectifying plate 18 in the high temperature chamber 12 flows toward the high temperature exhaust passage 13 along both side surfaces 18 a forming the concave curved surface of the rectifying plate 18. Moreover, since the length of both side surfaces 18a in the direction of the center line L is long (high), the two sides of the center line L are divided almost equally over both sides of the center line L, thereby preventing interference with each other and smoothly. Flowing.

  In FIG. 3, the length of the streamline represents the flow velocity of the combustion gas at that position. As a result, the passage resistance of the high temperature chamber 12 and the high temperature exhaust passage 13 can be greatly improved. The retention of the combustion gas in the high temperature chamber 12 due to circular recirculation and the retention of the combustion gas in the vicinity of the inlet of the high temperature exhaust passage 13 Is eliminated, and it becomes possible to exhaust the combustion gas at a flow rate corresponding to the minimum cross-sectional area of the high-temperature exhaust passage 13, and the exhaust efficiency is remarkably improved.

  Further, the shape of the high-temperature chamber is symmetrical with respect to the outlet of the high-temperature exhaust passage, that is, symmetrical with respect to the center line of the high-temperature exhaust passage. Thus, it can be divided into substantially equal sides and discharged into the high-temperature exhaust passage, and together with the rectifying plate, the residence of combustion gas in the high-temperature chamber can be reduced.

  The present invention is not limited to the exhaust passage of the two-cycle uniflow type diesel engine according to the above-described embodiment, and includes a main valve, a high temperature chamber, a high temperature exhaust passage, a low temperature exhaust passage, and a sub valve. The same applies to other types of internal combustion engines.

DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Valve seat 2a Exhaust port 3 Cylinder 5 Exhaust valve box 5a Exhaust port 6 High greenhouse 6a Inner wall surface 7 High temperature exhaust passage 7a Outlet 11 Exhaust valve box 11a Exhaust port 12 High greenhouse 12a Inner wall surface 12b Swelling part 12c Inlet 13 High temperature exhaust passage 13a Outlet 13c, 13d Consecutive section 14 of high greenhouse and high temperature exhaust passage entrance Low greenhouse (low temperature exhaust passage)
15 Low temperature exhaust passage 17 Current plate (first current plate)
17a Side 18 Current plate (second current plate)
18a Side 21 Main valve 21a Valve face 22 Valve stem 25 Sub valve 25a Radiation (spoke)
25b Skirt portion 26 Valve stem 27 Flow regulating member 27a Tip portion 27b Concave curved surface portion 29 Air piston 30 Hydraulic cylinder block 31 Hydraulic cylinder 35 Casing 36 Air spring chamber L Center line R1 of high temperature exhaust passage Radius of curvature of side of first flow straightening plate R2 Curvature radius of side face of second rectifying plate D0 Inner diameter of high temperature exhaust passage D1 Inner diameter of sub valve passage Dv Diameter of valve face of main valve O Center

Claims (5)

  A main valve (21) for exhausting combustion gas in the cylinder (3), and a high temperature for introducing high-temperature combustion gas provided in the exhaust valve box (11) and discharged from the cylinder through the main valve A chamber (12), a high temperature exhaust passage (13) provided in the exhaust valve box for discharging combustion gas in the high temperature chamber to the outside, and a main valve from the cylinder provided in the exhaust valve box. A low-temperature exhaust passage (14, 15) for discharging the low-temperature combustion gas discharged to the outside, and the flow of the combustion gas to the high-temperature exhaust passage and the low-temperature exhaust passage provided in the exhaust valve box In the exhaust passage structure of the internal combustion engine provided with a sub valve (25) for switching, the rectification smoothly guides the high-temperature combustion gas introduced into the high-temperature chamber to the inner wall surface (14a) of the high-temperature chamber to the high-temperature exhaust passage. A plate (17, 18) is provided; The rectifying plate has a first rectifying plate (17) provided on the side opposite to the outlet (13a) side of the high temperature exhaust passage and toward the center of the outlet side, and on the outlet side of the high temperature exhaust passage. And a second rectifying plate (18) provided toward the center of the outlet side, and both side surfaces (17a) of the first rectifying plate face the center of the outlet side of the high-temperature exhaust passage. The second rectifying plate (18) has both side surfaces (18a) extending from the tip toward the inner wall surface (12a) of the high temperature chamber so as to form an arcuate concave curved surface. The high temperature chamber extends from the tip toward the center on the outlet side to form an arc-shaped concave curved surface toward the inner wall surface of the high temperature chamber, and the high temperature chamber is formed between the center of the outlet of the high temperature exhaust passage and the high temperature chamber. It is formed in a substantially symmetrical shape with respect to the center line (L) connecting the center (O). An exhaust passage structure for an internal combustion engine characterized by Rukoto. A bulging portion (12b) formed by bulging an inner wall surface (12a) in the vicinity of the inlet (12c) of the high temperature chamber into a convex curved surface is provided in the high temperature chamber, and the bulging portion is provided in the high temperature chamber. The exhaust passage structure for an internal combustion engine according to claim 1, wherein the exhaust passage structure is formed in an annular shape so as to surround the inlet of the internal combustion engine.   The tip (27a) of the rectifying member (27) having a substantially inverted conical shape attached to the support member (30) that supports the valve stem (26) of the sub-valve (25) has an arcuate concave curved surface. The exhaust passage structure for an internal combustion engine according to claim 1 or 2, wherein the exhaust passage structure is reduced in diameter to extend toward the main valve (21).   The tip (27a) of the rectifying member (27) having a substantially inverted conical shape attached to the support member (30) that supports the valve stem (26) of the sub-valve (25) is connected to the high temperature chamber (12). The diameter of the bulging portion (12b) is reduced so as to form an arcuate concave curved surface (27b) corresponding to the convex curved surface, and the bulging portion (12b) is extended to the main valve (21) side, and The exhaust passage structure for an internal combustion engine according to claim 2, wherein the bulging portion of the high temperature chamber cooperates.   The tip (27a) of the rectifying member (27) having a substantially inverted conical shape attached to the support member (30) that supports the valve stem (26) of the sub-valve (25) has an arcuate concave curved surface (27b). The bulge of the high temperature chamber when the diameter of the high temperature chamber is reduced to extend toward the main valve (21) and the auxiliary valve (25) is operated to open the high temperature chamber (12). The exhaust passage structure for an internal combustion engine according to claim 2 or 4, wherein the exhaust passage structure is formed to face the portion (12b).

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