JP2008169720A - Cylinder head structure and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive cylinder head structure having exhaust port liners capable of improving strength, and having the high thermal insulation effect; and its manufacturing method. <P>SOLUTION: This cylinder head structure has collecting exhaust ports 6 and 7 merging exhaust gas of a plurality of exhaust ports formed inside a cylinder head 1 of a multicylinder internal combustion engine, and the metallic exhaust port liners 26 and 27 constituted as a double structure of an inside liner 31 constituting at least a part of the collecting exhaust ports 6 and 7 and an outside liner 32 arranged by interposing a clearance in the outer periphery of this inside liner 31 and fixed by enveloped casting when casting the cylinder head 1 as a lining of the collecting exhaust ports 6 and 7. Moreover, the exhaust port liners of this double structure have a straightening plate 34 regulating the flowing direction of the exhaust gas by continuing with an inlet opening part 23 opening in a midway part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cylinder head structure including a collective exhaust port that joins exhaust gases of a plurality of cylinders of a multi-cylinder engine, and a manufacturing method thereof.

  In order to increase the efficiency of the turbocharger arranged downstream from the past or reduce the thermal load of the engine, a collective exhaust port that joins the exhaust of multiple exhaust ports of a multi-cylinder engine is connected to the cylinder head body inside the cylinder head. Has proposed a cylinder head structure provided in a thermally insulated state (see Patent Document 1).

This is formed inside a cylinder head of a multi-cylinder internal combustion engine, and a collective exhaust port that joins the exhaust of a plurality of exhaust ports, and as a lining of the collective exhaust port, the cylinder head is fixed by a caster when casting the cylinder head. A ceramic exhaust port liner that divides the collective exhaust port into a plurality of portions, and a cooling water passage provided along the seam near the seam between the plurality of exhaust port liners. .
No. 7-34198

  However, since the ceramic liner is used in the above-mentioned conventional example, the heat treatment temperature such as the solution treatment of the cylinder head, which is performed to improve the strength in response to the high performance of the engine, is increased. There is a problem in that the port liner is liable to crack during heat treatment, and there is a limit in improving the strength of the cylinder head.

  In order to enhance the heat insulation effect, it is necessary to provide a heat insulation layer between the exhaust port and the exhaust port liner. However, a ceramic port liner is difficult to form an air layer, and a large heat insulation effect cannot be exhibited. In addition, the ceramic material itself is expensive and needs to be divided and disposed, so that there is a problem of high cost.

  Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide an inexpensive cylinder head structure capable of improving strength and having a high heat insulating effect, and a manufacturing method thereof.

  The present invention provides a collective exhaust port that is formed inside a cylinder head of a multi-cylinder internal combustion engine and merges exhaust gases from a plurality of exhaust ports, an inner liner that forms at least a part of the collective exhaust port, and an outer periphery of the inner liner. It is configured in a double structure with an outer liner disposed with a gap interposed therebetween, and includes a metal exhaust port liner that is fixed as a lining of the collective exhaust port by a caster during casting of the cylinder head, The dual-structure exhaust port liner includes a rectifying plate that is connected to an inlet opening that opens in the middle and regulates the flow direction of the exhaust gas.

  Therefore, in the present invention, the inlet that is configured in a double structure of the inner liner that constitutes at least a part of the collective exhaust port and the outer liner that is arranged with a gap between the outer periphery of the inner liner and that opens in the middle portion. A cylinder head is formed by forming a metal exhaust port liner provided with a baffle plate connected to the opening to regulate the flow direction of exhaust gas, and fixed as a lining of the collective exhaust port by casting in the cylinder head. Even when high-temperature heating or rapid cooling is performed in a heat treatment process such as solution treatment of a cast product, the exhaust port liner does not crack and the strength can be improved. be able to. In addition, the exhaust gas can flow smoothly from the individual exhaust port toward the outlet opening of the exhaust port liner by providing a flow straightening plate that regulates the flow direction of the exhaust gas in series with the inlet opening that opens in the middle. Therefore, the gas exchange in the combustion chamber is good and the output performance can be improved.

  Hereinafter, a cylinder head structure and a manufacturing method thereof according to the present invention will be described based on an embodiment. 1 is a sectional view of a cylinder head according to a first embodiment to which the present invention is applied, FIG. 2 is a layout diagram of an exhaust port provided in the cylinder head, and FIG. 3 is a layout diagram of an exhaust port liner provided in the exhaust port of FIG. FIG. 4 is a cross-sectional view of the exhaust port liner.

  FIG. 1 shows a cross-sectional view of a cylinder head 1. An intake port 3 and an exhaust port 4 connected to a combustion chamber 2, and a water jacket 5 for cooling them are arranged above and below the exhaust port 4. Water jacket 5A and exhaust port lower water jacket 5B, intake port portion water jacket 5C arranged in a portion surrounded by intake port 3 and combustion chamber 2, exhaust port 4 and intake port 3 at the upper portion of combustion chamber 2, And a combustion chamber water jacket 5D disposed in a portion sandwiched between the two.

  This cylinder head 1 is for three cylinders having two exhaust valves per cylinder. As shown in FIG. 2, a plurality of exhaust ports of each cylinder are connected to exhaust valves of respective combustion chambers (not shown). 11 to 16 are arranged, and these individual exhaust ports 11 to 16 are constituted by a left side collective exhaust port 6 and a right side collective exhaust port 7 which join three ports and gather at the outlet ports 17 and 18 respectively. The cylinder head structure having such a configuration can be used for a cylinder head of a three-cylinder engine or a V-type six-cylinder engine. The left collective exhaust port 6 and the right collective exhaust port 7 are formed in a symmetrical shape. That is, in the right side collective exhaust port 7, the exhaust ports 15 and 16 from the two ports far from the center in the cylinder row direction are gathered together at the first port gathering portion 19 to constitute the gathering port 20. This collective port 20 is configured to be gathered into one by the exhaust port 14 from the remaining port on the center side and the second cylinder collective portion 21 and continue to the outlet port 18. The left collective exhaust port 6 is similarly configured.

  In the left collective exhaust port 6 and the right collective exhaust port 7 having the above-described configuration, the two exhaust ports 15 and 16 are merged in the first collective portion 19, and a plurality of wall surfaces of the collective port 20 downstream of the first collective portion 19 are provided on the wall surface. As a result of the exhaust gas from the other ports collecting and flowing, the wall surface temperature rises from the upstream side. Further, in the second collecting portion 21, the remaining exhaust ports 14 are merged, and the exhaust gas from the three ports merges or alternately flows up to the outlet port 18 to further increase the wall surface temperature. For this reason, it is necessary to insulate the exhaust port 7 and the main body 1A of the cylinder head 1 from the first collecting portion 19 to the outlet port 18.

  Further, in the second collecting portion 21, the exhaust gas flow G2 newly joins in the second collecting portion 21 with respect to the exhaust gas flow G3 in the collecting port 20 merged in the first collecting portion 19, so that the first It is necessary to arrange a rectifying plate that rectifies the gas flows G2 and G3 and prevents mutual interference in the second collecting portion 21.

  FIG. 3 shows a left exhaust port liner 26 and a right exhaust port liner 27 which are arranged on the inner wall surfaces of the exhaust ports 6 and 7 shown in FIG. The left and right exhaust port liners 26 and 27 are symmetrical with the same configuration, and only the right exhaust port liner 27 will be described here. As shown in FIG. 3, the right exhaust port liner 27 surrounds the first inlet opening 22 that surrounds the first collecting portion 19 of the exhaust port 7 and the exhaust port 14 that newly joins the second collecting portion 21. A thin cylindrical shape provided with a second inlet opening 23 and an outlet opening 24 surrounding the outlet opening 18 so as to cover (line) the wall surface of the exhaust port 7 between the openings 22-24. It consists of a metal plate.

  As shown in FIG. 4, the right exhaust port liner 27 is formed of double-walled metal plates 31 and 32 (liners) inside and outside, and a double-sided metal inside and outside the wall surface between the openings 22 to 24. The air layer 30 is formed by providing a gap between the plates 31 and 32 (liner). Further, the outer metal plate 32 is bent to the inner metal plate 31 side at each of the openings 22 to 24, and the bent end portion is crimped to the opening of the inner metal plate 31 so that the inner and outer two are crimped. Heavy metal plates 31 and 32 are configured so as to be integrated with each other through the crimping portion 33. Of the crimping portions 33 formed in the openings 22 to 24, either the crimping portion 33 constituting the outlet opening 24 or the crimping portion 33 constituting the first and second inlet openings 22 and 23. One crimping portion 33 is fastened by welding or caulking or the like, and the other crimping portion 33 is kept in a crimped state without being fastened.

  The second inlet opening 23 is formed by cutting a part of the cylindrical inner and outer metal plates 31 and 32 into a slit shape, bending one end face of the slit and a portion connected to the slit into a semicircle. The other end face where the slits face each other and the portion connected to the slit are bent so as to be recessed in the remaining semicircular shape, thereby forming a substantially circular opening. Therefore, the inner and outer metal plates 31 and 32 that are disposed around the collecting port 20 and are connected to the second inlet opening 23 have their portions 31A and 32A recessed along the opening edge of the second inlet opening 23. The exhaust gas flow that flows through the collecting port 20 and the exhaust gas that flows through the new exhaust port 14 are configured by forming a port wall surface of the exhaust port 14 that is newly connected to the second inlet opening 23 at the second junction 21. The rectifying plate 34 at the time of merging is formed. The rectifying plate 34 rectifies the flow direction of the exhaust gas from the new exhaust port 14 flowing in from the second inlet opening 23 toward the outlet opening 24 (see G4 in the figure), and the exhaust gas flowing in the collecting port 20 The flow direction of the gas is also rectified toward the outlet opening 24 (see G5 in the figure), and as a result, the interference between the flow direction of the exhaust gas flowing in the collecting port 20 and the flow direction of the exhaust gas flowing in from the new exhaust port 14 Function to suppress.

  The right exhaust port liner 27 having the above-described configuration surrounds the inner metal plate 31 (inner liner) having a cylindrical integrated structure including the inlet openings 22 and 23 and the outlet opening 24, and the inner metal plate 31. It can be configured by a three-part structure including an outer metal plate 32 (outer liner) that is arranged and divided into two parts, the front side and the opposite side of the sheet of FIG. That is, with respect to the exhaust port 14, no liner is provided in a portion from the exhaust upstream end to the second port assembly 21, and the exhaust port 14 is connected to the inlet opening 23 of the inner liner 31 by the second port assembly 21. It is made the structure which communicates with. As a result, the liner does not have a complicated branch (aggregate) shape, and the inner liner 31 can be molded as an integrally molded part by hydraulic molding of the cylindrical member. Incidentally, when the exhaust port 14 is provided with a liner extending from the second port assembly portion 21, the inner liner 31 needs to be divided into two parts like the outer liner 32. As a result, the exhaust port liner has four parts. It becomes a structure, and the number of parts and the number of assembling steps are increased, which makes the structure expensive.

  Although the configuration of the right exhaust port liner 27 has been described above, the left exhaust port liner 26 is also configured in the same manner, and a description of the specific structure thereof is omitted.

  In the cylinder head structure having the above-described configuration, the exhaust port liners 26 and 27 having a double-walled structure made of thin metal are used. Therefore, the exhaust port liners 26 and 27 are held by the core constituting the exhaust port 4. Can be cast into the cylinder head 1, and even when quenching in heat treatment such as solution treatment after casting, cracks do not occur in the port liners 26 and 27, and light alloy is produced at a high heat treatment temperature. The strength of the made cylinder head 1 can be improved. In addition, since the exhaust port liners 26 and 27 are made of a thin metal having a cylindrical inner and outer double integral structure, material costs and manufacturing processes can be simplified, and an inexpensive exhaust port liner can be obtained. Moreover, since it is not divided | segmented, it is not necessary to arrange | position a cooling water channel | path and to cool partially, and also in this point, it can comprise at low cost.

  Further, since the air layer 30 is arranged between the inner and outer double thin metal, the gas temperature of the exhaust gas at the time of cold start is excellent in heat dissipation due to the presence of the heat insulating layer constituted by the air layer 30. The temperature of the exhaust gas discharged from the outlet ports 17 and 18 is suppressed by reducing heat transfer and heat dissipation to the light alloy cylinder head 1 body and the cooling water jackets 5A and 5B above and below the exhaust port 4. It can be kept relatively high, the activation of the exhaust purification catalyst arranged in the downstream exhaust pipe can be accelerated, and the exhaust gas discharged without being treated can be reduced.

  Further, even during high load operation after the engine is warmed up, the heat flow that is radiated from the exhaust port 4 to the cooling water of the cooling jacket 5 through the light alloy cylinder head 1 body is suppressed. The amount of heat to be radiated by the system can be reduced, and the heat load of the cooling system can be reduced.

  Further, since the exhaust port liners 26 and 27 include a rectifying plate 34 formed so as to constitute a part of the wall surface of the exhaust port 14 that is connected to the second inlet opening 23 and newly connected, the exhaust port 14 and the collecting port 20 exhaust gas flows can be led to the outlet port 18 without interfering with each other, gas exchange in the combustion chamber 2 can be improved, and output can be improved. Although not shown, when a turbocharger is mounted downstream of the outlet ports 17 and 18, the engine output and fuel efficiency are improved by effectively utilizing exhaust gas energy such as exhaust gas temperature and gas flow. be able to.

  The openings 22 to 24 formed by the inner and outer double-walled metal plates 31 and 32 are fitted in a crimped state, and the crimping portion 33 constituting the outlet opening 24 or the first and second inlets. One of the crimping parts 33 constituting the openings 22 and 23 is fastened by welding or caulking or the like, and the other crimping part is left in a crimped state without being fastened. Even if there is a difference in thermal expansion due to a temperature difference, the stress is absorbed by the sliding of the crimping part 33, so that deformation and breakage can be prevented, and its reliability can be improved.

  In the above-described embodiment, the inner and outer double wall structures of the exhaust port liners 26 and 27 have been described by forming the cylindrical thin metal plates 31 and 32 into shapes. For each of the outer walls, first, the inner wall surface is formed in a split structure, and then the outer wall surface of the split wall structure is covered on the outer periphery of the inner wall surface, whereby an exhaust port liner having an inner / outer double wall structure may be configured. .

  In the present embodiment, the following effects can be achieved.

  (A) Collective exhaust ports 6 and 7 formed inside a cylinder head 1 of a multi-cylinder internal combustion engine for joining exhaust gases of a plurality of exhaust ports, and an inner liner 31 constituting at least a part of the collective exhaust ports 6 and 7 And the outer liner 32 arranged with a gap between the outer periphery of the inner liner 31 and fixed as a lining of the collective exhaust ports 6 and 7 by casting in the cylinder head 1 during casting. The metal exhaust port liners 26 and 27 are provided. For this reason, the exhaust port liners 26 and 27 are not cracked even when high-temperature heating and rapid cooling are performed in a heat treatment process such as solution treatment of the cylinder head 1 cast product, and the strength can be improved and the heat insulating effect can be obtained. And an inexpensive cylinder head structure. In addition, the exhaust port liners 26 and 27 having the double structure include a rectifying plate 34 that is connected to the inlet opening 23 that opens in the middle and regulates the flow direction of the exhaust gas. Since the exhaust gas can flow smoothly toward the outlet opening 24 of 26, the gas exchange in the combustion chamber 2 becomes good and the output performance can be improved.

  (A) Since the exhaust port liners 26 and 27 having the double structure are formed of a thin metal in which the air layer 30 is provided between the inner liner 31 and the outer liner 32, the heat insulation effect is enhanced by the air layer 30. In addition, since it is made of a thin metal, it is possible to improve the warm-up characteristic from the low temperature start, accelerate the activation of the catalyst arranged downstream, and promote the purification of the exhaust gas. Further, even during a high load operation after the engine warms up, the heat flow from the exhaust port 4 to the cooling water is suppressed, so the load on the cooling system can be reduced.

  (C) The exhaust port liners 26 and 27 having a double structure are formed by the cylindrical metal plates 31 and 32 from the inlet openings 22 and 23 to the outlet opening 24, thereby combining a plurality of members. Compared to the case, the material cost and the manufacturing process can be simplified, and an inexpensive exhaust liner can be obtained. In addition, since it is not necessary to provide a cooling water passage so as to suppress heat transfer from the dividing portion of the exhaust port liner as in the prior art, it can be formed at low cost.

  (D) The inner liner 31 is integrally formed from a cylindrical member by hydraulic molding, and the outer liner 32 joins two members divided in a direction intersecting the exhaust flow direction. Thus, the inner metal plate 31 (inner liner) of a cylindrical integrated structure and the outer metal plate 32 (outer side) divided in two so as to surround the inner metal plate 31 are configured. It is possible to configure a three-part structure with a liner) and to reduce the number of parts.

  (E) The exhaust port liners 26, 27 having a double structure are formed by bending the end portions of the outer liner 32 toward the inner peripheral side at the inlet openings 22, 23 and the outlet opening 24, and bending the bent end portions of the inner liner 31. The inlet crimping portion 33 and the outlet crimping portion 33 are crimped to the outer periphery, and one of the inlet crimping portion 33 and the outlet crimping portion 33 is fastened to each other by welding or caulking, whereby the inner and outer liners 31, The difference in thermal expansion due to the temperature difference of 32 can be absorbed by the slip of the crimping part 33, the generation of thermal stress can be suppressed, and the reliability can be improved.

1 is a schematic sectional view of a cylinder head structure showing an embodiment of the present invention. The layout diagram of the exhaust port similarly provided in a cylinder head. FIG. 3 is a layout diagram of an exhaust port liner provided in the exhaust port of FIG. 2. Sectional drawing of an exhaust port liner.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Combustion chamber 3 Intake port 4, 6, 7 Exhaust port 5 Water jacket 11-16 Individual exhaust port 17, 18 Outlet port 19, 21 Collecting part 20 Collecting port 22, 23 Inlet opening 24 Outlet opening 26, 27 Exhaust Port liner 30 Air layer 31 Inner liner 32 Outer liner 33 Crimping part 34 Current plate

Claims (6)

A collective exhaust port that is formed inside a cylinder head of a multi-cylinder internal combustion engine and merges exhaust from a plurality of exhaust ports;
Casting of the cylinder head as a lining of the collective exhaust port is configured with a double structure of an inner liner that constitutes at least a part of the collective exhaust port and an outer liner that is disposed with a gap around the outer periphery of the inner liner. An exhaust port liner made of metal that is fixed by a caster during
The dual-structure exhaust port liner includes a rectifying plate that is connected to an inlet opening that opens in a middle portion and regulates the flow direction of exhaust gas.   2. The cylinder head structure according to claim 1, wherein the dual structure exhaust port liner is formed of a thin metal having an air layer between an inner liner and an outer liner.   The cylinder head structure according to claim 2, wherein the dual structure exhaust port liner is formed of a cylindrical metal plate from an inlet opening to an outlet opening.   The inner liner is integrally formed from a cylindrical member by hydraulic molding, and the outer liner is formed by joining two members that are divided in a direction intersecting the exhaust flow direction. The cylinder head structure according to claim 3, wherein the cylinder head structure is provided.   The dual structure exhaust port liner has an inlet crimping section and an outlet crimping section in which the end of the outer liner is bent to the inner peripheral side at the inlet opening and the outlet opening, and the bent end is crimped to the outer periphery of the inner liner. 5. The cylinder according to claim 1, wherein one of the inlet crimping portion and the outlet crimping portion is fastened to each other by welding or caulking. Head structure. A method of manufacturing a cylinder head comprising a collective exhaust port formed inside a cylinder head of a multi-cylinder internal combustion engine and merging exhaust gases of a plurality of exhaust ports,
Exhaust gas is connected to an inlet opening that is formed in a double structure of an inner liner that constitutes at least a part of the collective exhaust port and an outer liner that is disposed around the outer periphery of the inner liner and that opens in the middle. Forming a metal exhaust port liner with a rectifying plate that regulates the gas flow direction,
A method of manufacturing a cylinder head, wherein the metal exhaust port liner is fixed as a lining of the collective exhaust port with a caster during the casting of the cylinder head.

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