JP2018003602A - Intake passage structure for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the adhesion force of a heat insulation member to the inner face of an intake port.SOLUTION: An intake passage structure for an engine includes an intake port 5 provided in a cylinder head 1 of the engine and connected to a combustion chamber 3, a heat insulation member 20 arranged along the inner face of the intake port 5, a mounting hole 11 which is opened into the intake port 5 and through which a fuel injection device 10 is inserted, and a heat insulation material supply hole 25 opened into the intake port 5 for supplying resin, the mounting hole 11 being arranged in a diameter enlarged part 12 formed in the intake port 5, the heat insulation member 20 including a first protruded part 26 extending into the heat insulation material supply hole 25, and a second protruded part 22 formed along the diameter enlarged part 12. The first protruded part 26 includes an upstream side abutting part 26a abutting on the inner wall face on the upstream side of the heat insulation material supply hole 25 for restricting the movement to the upstream side. The opening of the heat insulation material supply hole 25 into the intake port 5 is located in the diameter enlarged part 12 at its upstream side further than the opening of the mounting hole 11.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an intake passage structure for an engine that enables good combustion in a combustion chamber.

  The intake air supplied into the combustion chamber of the engine is sucked into the combustion chamber through an intake passage in the intake manifold and an intake passage (hereinafter referred to as an intake port) provided in the cylinder head.

  Since the intake manifold and the cylinder head are heated by the heat transmitted from the combustion chamber, the intake air tends to rise in temperature by receiving heat from the intake passage in the intake manifold and the inner surface of the intake port in the cylinder head.

  In particular, in a high compression ratio engine, if the intake air temperature rises, knocking is more likely to occur than in a low compression ratio engine. In such a case, for example, the ignition timing is retarded and the knocking is performed. It is necessary to cope with. Since the ignition timing retards the improvement of fuel consumption, it is desirable to suppress the rise in intake air temperature as much as possible.

  Therefore, in order to suppress an increase in the temperature of the intake air, a technique has been proposed in which a material having a low heat transfer coefficient such as a resin is brought into close contact with the inner surface of a metal intake port to form a heat insulating member for intake (Patent Document 1). reference).

JP 7-259642 A

  The heat insulating member on the inner surface of the intake port is made of resin that is in close contact with the inner surface of the cylinder head by injection molding or the like. However, when the heat insulating member is heated by the heat of the cylinder head, the heat insulating member tends to thermally expand. For this reason, if the adhesion force of the heat insulating member to the inner surface of the intake port is weak, the heat insulating member may be thermally expanded to rise to the inner diameter side of the intake port and peel from the inner surface of the intake port.

  Also, when fixing the intake manifold to the cylinder head, the heat insulating member on the inner surface of the cylinder head is pushed to the combustion chamber side by the intake manifold, and the heat insulating member can be lifted to the inner diameter side of the intake port and peeled off from the inner surface of the intake port There is sex.

  If the heat insulating member is peeled off, a smooth flow of intake air is hindered due to an increase in intake resistance, and a predetermined intake air amount is not supplied to the combustion chamber, which is not preferable. For this reason, it is desirable that the adhesion of the heat insulating member to the inner surface of the intake port is as strong as possible.

  Accordingly, an object of the present invention is to increase the adhesion of the heat insulating member to the inner surface of the intake port.

  In order to solve the above problems, the present invention provides an intake port provided in a cylinder head of an engine and connected to a combustion chamber, a heat insulating member disposed along an inner surface of the intake port, and an intake port Insulating passage structure of an engine provided with a first protrusion that extends into the inside of the heat insulating material supply hole.

  And an attachment hole that is opened in the intake port and into which the fuel injection device is inserted. The attachment hole is disposed in a large-diameter portion formed in the intake port, and the heat insulating member includes the large-diameter portion. The structure provided with the 2nd protrusion part arrange | positioned along can be employ | adopted.

  In this case, it is possible to employ a configuration in which the first projecting portion includes an upstream contact portion that contacts the inner wall surface of the heat insulating material supply hole on the upstream side in the intake flow direction.

  The aspect provided with the said attachment hole and the said heat insulating material supply hole WHEREIN: The said mounting hole and the said heat insulating material supply hole employ | adopted the structure arrange | positioned on the opposite side across the center part of the flow-path cross section of the said intake port. can do.

  Further, in the aspect including the mounting hole and the heat insulating material supply hole, the opening of the heat insulating material supply hole into the intake port is located upstream of the opening of the mounting hole into the intake port. It is possible to adopt a configuration to

  In each of these aspects, it is possible to employ a configuration in which the heat insulating material supply hole is provided perpendicular to the flow direction connecting the upstream side and the downstream side of the intake port.

  Further, in each of these aspects, it is possible to employ a configuration in which the first protrusion includes a downstream contact portion that contacts the inner wall surface of the heat insulating material supply hole on the downstream side in the intake flow direction.

  In the present invention, the resin heat insulating member disposed along the inner surface of the intake port is provided with the first protrusion that extends into the heat insulating material supply hole that opens into the intake port. The adhesion of the heat insulating member to the inner surface can be increased.

It is sectional drawing of the connection location vicinity of the intake port and intake manifold channel | path which show embodiment of this invention. It is a principal part enlarged view at the time of formwork installation. It is a principal part enlarged view which shows other embodiment. It is a principal part enlarged view which shows other embodiment. It is a principal part enlarged view which shows other embodiment.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the combustion chamber 3 and the vicinity of the cylinder head 1 of the engine of this embodiment, and a part of the intake manifold 30 connected to the cylinder head 1. FIG. 2 is an enlarged view of a main part showing a method of manufacturing these intake passage structures.

  A piston is accommodated in the cylinder of the engine. A combustion chamber 3 is formed by the upper surface of the cylinder, the inner peripheral surface, the upper surface of the piston, and the like. The cylinder head 1 above the combustion chamber 3 has an intake port 5 for sending intake air into the combustion chamber 3, an exhaust port drawn from the combustion chamber 3, and a fuel injection device for injecting fuel into the combustion chamber 3 and the intake port 5. (Injector) 10 etc. are provided.

  An intake valve hole 4 that is an opening to the combustion chamber 3 of the intake port 5 is opened and closed by the intake valve 2. Similarly, an exhaust valve hole that is an opening of the exhaust port to the combustion chamber 3 is also opened and closed by the exhaust valve.

  In these drawings, members and means on the intake side that are directly related to the present invention are mainly shown, and other members and the like are not shown. In the drawings, only one cylinder is shown, but the engine may be a single cylinder or a multi-cylinder having a plurality of cylinders.

  An intake manifold 30 is connected to the cylinder head 1 having the intake port 5. An intake manifold passage 31 that forms an intake passage together with the intake port 5 is provided in the intake manifold 30. The intake manifold passage 31 and the intake port 5 constitute part of an intake passage for supplying intake air introduced from outside air through an air cleaner or the like to the combustion chamber 3.

  In this embodiment, the cylinder head 1 is made of metal (made of aluminum), and the intake manifold 30 is made of resin. The intake manifold 30 may be made of a metal such as a casting.

  The cross-sectional shape of the intake port 5 is such that the maximum diameter in the vertical direction connecting the upper surface side and the lower surface side of the passage is near the maximum diameter in the width direction orthogonal to the upper surface side and the lower surface side in the vicinity of the connection portion to the intake manifold passage 31 on the upstream side. The so-called horizontally long oval shape is also set small. Also, the cross-sectional shape of the intake manifold passage 31 is such that the maximum diameter in the vertical direction connecting the upper surface side and the lower surface side of the passage near the connection portion to the intake port 5 is larger than the maximum diameter in the width direction orthogonal to the upper surface side. It is a horizontally long oval shape set small.

  The intake manifold 30 is fixed to the cylinder head 1 by inserting a bolt rising from the cylinder head 1 side through a hole in the flange portion 32 provided at the end of the intake manifold passage 31 of the intake manifold 30 and tightening with a nut or the like. Done. By this tightening, the upstream end surface 6 of the intake port 5 and the intake manifold end surface 32a, which is the downstream end surface of the intake manifold passage 31, come into surface contact, and the intake port 5 and the intake manifold passage 31 are connected in an airtight manner.

  At this time, an annular seal groove is formed in the intake manifold end surface 32a, and an annular packing is accommodated in the seal groove. When the packing is pressed against the upstream end face 6 of the intake port 5, the airtightness is enhanced.

  A heat insulating member 20 is disposed on the inner surface of the intake port 5. The heat insulating member 20 is formed with a predetermined thickness along the entire inner circumference of the intake port 5, and the shape thereof corresponds to the cylindrical inner surface portion 13 of the intake port 5 in the upstream region near the intake manifold 30. It has a cylindrical shape. This cylindrical portion of the heat insulating member 20 is referred to as a cylindrical portion 23.

  The heat insulating member 20 is formed by resin injection molding. The cylinder head 1 is provided with an injection gate (heat insulating material supply hole) 25 that is a through hole that faces the space in the intake port 5 from the external space, corresponding to the method of manufacturing the heat insulating member 20 by injection molding. The heat insulating material supply hole 25 opens on the lower surface of the inner surface of the intake port 5 on the upstream side of the central portion with respect to the entire length of the intake port 5.

  After a predetermined mold 40 is inserted and fixed in the intake port 5, an injection port of an injection (injector) A is inserted into the heat insulating material supply hole 25, and between the inner surface of the intake port 5 and the outer surface of the mold Is filled with the resin injected upward from the injection (injection machine) A. When the mold 40 is removed after the resin is cured, the heat insulating member 20 is fixed to the inner surface of the intake port 5.

  As shown in FIG. 2, the mold 40 includes a cylindrical portion 41 that faces the cylindrical inner surface portion 13 that is the upstream region of the intake port 5 and a divided portion that faces the vicinity of the enlarged-diameter portion 12 that is the downstream region. 42, 43, 44.

  The cylindrical portion 41 of the mold 40 has a cylindrical shape and is opposed to the cylindrical inner surface portion 13 of the intake port 5 with a predetermined gap. The cylindrical portion 41 can be inserted into and removed from the intake port 5 from the upstream opening of the intake port 5.

  The divided portions 42, 43, 44 of the mold 40 have a shape that matches the shape near the enlarged diameter portion 12 and faces the inner surface of the intake port 5 via a predetermined gap. The divided portions 42, 43, and 44 are a plurality of members that are divided so as to be inserted into and removed from the intake port 5 from the combustion chamber 3 side, which is an opening on the downstream side of the intake port 5. After being inserted into the port 5, it can be assembled into a predetermined shape. Further, after the resin is cured, it can be taken out from the intake valve hole 4 by dividing.

  An upstream end portion of the mold 40 is an upstream flange portion 45 that is in surface contact with the upstream end surface 6 of the intake port 5. The upstream flange portion 45 closes an upstream end portion of the mold space formed between the outer surface of the tubular portion 41 or the divided portion 42 of the mold 40 and the inner surface of the intake port 5. Further, the downstream end of the formwork space is closed by the dividing portions 43 and 44.

  The heat insulating member 20 formed by injection molding of resin into the mold space is provided with a first protrusion 26 that protrudes into the heat insulating material supply hole 25 in the vicinity of the heat insulating material supply hole 25. It becomes. The first protrusion 26 is formed integrally with the cylindrical portion 23 and extends into the heat insulating material supply hole 25.

  The first projecting portion 26 contacts the upstream inner wall surface of the injection gate 25 with respect to the flow direction of the intake port 5 and regulates the upstream movement of the heat insulating member 20. A contact portion 26a is provided.

  If the axial direction of the cylinder of the cylinder is assumed to be a vertical direction, the intake port 5 is inclined upward in the direction from the combustion chamber 3 side toward the intake manifold passage 31 side, that is, the intake port 5 The direction of the center line c in the flow path cross section is an upward gradient from the downstream side toward the upstream side.

  The upstream contact portion 26a is a cylindrical surface that is in surface contact with the inner surface of the heat insulating material supply hole 25 having a circular cross section, and the cylindrical axis direction of the cylindrical surface is the vertical direction along the axial direction of the cylinder. For this reason, the upstream contact portion 26 a is a key-like portion that protrudes in a direction intersecting the direction of the center line c of the flow path cross section of the intake port 5. This key-like portion engages with the inner surface of the heat insulating material supply hole 25 to increase the degree of adhesion between the heat insulating member 20 and the inner surface of the intake port 5. Further, the upstream contact portion 26 a of the first protrusion 26 is in contact with the upstream inner wall surface of the heat insulating material supply hole 25, thereby restricting the upstream movement of the heat insulating member 20.

  Further, the lower surface 26b of the first projecting portion 26 is in close contact with the upper surface of a plug member (plug) 27 that is inserted into the injection gate 25 after the injection A is extracted.

  Further, in the downstream region near the fuel chamber 3, an attachment hole 11 for attaching the fuel injection device 10 is opened on the upper surface in the intake port 5. In the vicinity of the mounting hole 11, the inner surface of the intake port 5 constitutes an enlarged diameter portion 12 including a downwardly concave upper surface provided with an upstream inclined surface 12 a and a downstream inclined surface 12 b. The attachment hole 11 opens in the upstream inclined surface 12a facing the intake valve hole 4 side. The heat insulating member 20 is formed with a predetermined thickness along the entire inner circumference of the intake port 5 even in the vicinity of the enlarged diameter portion 12. The vicinity of the enlarged diameter portion 12 in the heat insulating member 20 is referred to as a second protruding portion 22. The second protrusion 22 is also formed integrally with the cylindrical portion 23.

  The mounting hole 11 of the fuel injection device 10 and the heat-insulating material supply hole 25 for injecting the resin are arranged on opposite sides of the central portion of the flow path cross section of the intake port 5. That is, in this embodiment, the attachment hole 11 is opened on the upper surface in the intake port 5, and the heat insulating material supply hole 25 is opened on the lower surface in the intake port 5. For this reason, in the heat insulating member 20, the second protrusion 22 that enters the upper surface of the concave enlarged diameter portion 12, and the first protrusion 26 that enters the heat insulating material supply hole 25 are formed on the upper surface side and the lower surface in the intake port 5. It is the arrangement | positioning which mutually opposes between the sides. Thus, by arranging the second protrusion 22 and the first protrusion 26 to face each other between the inner surfaces of the intake port 5, the degree of adhesion between the heat insulating member 20 and the inner surface of the intake port 5 is increased. Strengthening is planned.

  In this embodiment, as shown in FIG. 1, the opening of the heat insulating material supply hole 25 into the intake port 5 is located upstream of the opening of the attachment hole 11 into the intake port 5. For this reason, the fuel injected from the fuel injection device 10 inserted through the mounting hole 11 is unlikely to reach the heat insulating material supply hole 25. Although the heat insulating material supply hole 25 is closed by the plug member 27, even if the heat insulating member 20 covering the heat insulating material supply hole 25 is deteriorated with time, the fuel enters the heat insulating material supply hole 25. Because I want to avoid.

  Further, the temperature in the intake port 5 becomes higher as it is closer to the combustion chamber 3, and conversely, it becomes lower as it is farther from the combustion chamber 3. For this reason, the heat insulating material supply hole 25 is arranged in the upstream region where the temperature is as low as possible, that is, upstream of the opening of the mounting hole 11 of the fuel injection device 10, thereby insulating the portion covering the heat insulating material supply hole 25. The thermal influence on the member 20 is reduced.

  In particular, in the embodiment of FIG. 1, the opening of the heat insulating material supply hole 25 into the intake port 5 is upstream of the opening of the attachment hole 11 and further than the upstream end of the recessed portion of the enlarged diameter portion 12. Located upstream. Here, the point x in FIG. 1 is a point located symmetrically from the upstream end of the concave portion of the enlarged diameter portion 12 with the center line c of the flow path cross section of the intake port 5 in between. The opening of the heat insulating material supply hole 25 into the intake port 5 is in the range upstream of the point x, in terms of avoiding the arrival of fuel to the heat insulating material supply hole 25 and suppressing the temperature rise. Further preferred. That is, with respect to the range of the total length L of the heat insulating member 20 with respect to the flow direction of the intake air in the intake port 5, the heat insulating material supply hole 25 is in a region upstream of the range L ′ of the enlarged diameter portion 12. Further preferred.

  Another embodiment is shown in FIG. In the embodiment of FIG. 3, the direction of the heat insulating material supply hole 25 in the embodiment of FIG. 1 is perpendicular to the flow direction connecting the upstream side and the downstream side of the intake port 5. In FIG. 3, the axial center p of the heat insulating material supply hole 25 having a circular cross section is in a direction orthogonal to the center line c of the flow path cross section of the intake port 5.

  As a result, the first projecting portion 26 contacts the inner wall surface on the downstream side with respect to the flow direction of the intake port 5 in the inner surface of the heat insulating material supply hole 25 and regulates the downstream movement. It can be set as the structure provided with the part 26c.

  Similarly to the upstream contact portion 26a, the downstream contact portion 26c is a cylindrical surface that is in surface contact with the inner wall surface of the heat insulating material supply hole 25 having a circular cross section, and the cylinder axis direction of the cylindrical surface is the cylinder axis direction. In contrast, it extends vertically with a slight angle. For this reason, the downstream contact portion 26 c becomes a key-shaped portion that protrudes in a direction intersecting the direction of the center line c of the flow path cross section of the intake port 5, and this key-shaped portion is the heat insulating material supply hole 25. Engage with the inner surface. Thereby, the contact | adherence degree of the heat insulation member 20 and the inner surface of the intake port 5 is raised, and the movement to the downstream of the heat insulation member 20 is controlled.

  Furthermore, another embodiment is shown in FIG. In the embodiment of FIG. 4, the opening of the heat insulating material supply hole 25 into the intake port 5 is positioned directly below the opening of the attachment hole 11. Specifically, the axial center p of the heat insulating material supply hole 25 having a circular cross section is located immediately below the upstream end of the concave portion of the diameter-enlarged portion 12 (point y in the figure).

  In this embodiment, in terms of the effect of avoiding the arrival of fuel to the heat insulating material supply hole 25 and the effect of suppressing the temperature rise, the second protrusion 22 and the first The effect of strengthening the degree of adhesion between the heat insulating member 20 and the inner surface of the intake port 5 by arranging the protrusions 26 to face each other between the inner surfaces of the intake port 5 can be expected. In addition, it is possible to expect an effect of strengthening the degree of adhesion between the heat insulating member 20 and the inner surface of the intake port 5 by the first protrusion 26 entering the heat insulating material supply hole 25 and preventing the heat insulating member 20 from moving.

  In each of these embodiments, the heat insulating material supply hole 25 is opened on the lower surface in the intake port 5, but the direction of the opening of the heat insulating material supply hole 25 in the intake port 5 is on the lower surface in the intake port 5. Is not limited, and a case of a side surface or the like in the intake port 5 is also assumed. However, it is desirable that the attachment hole 11 to which the fuel injection device 10 is attached and the heat insulating material supply hole 25 are disposed on the opposite sides with respect to the central portion of the flow path cross section of the intake port 5.

  Furthermore, another embodiment is shown in FIG. FIG. 5 shows an embodiment of an engine that includes a direct injection type fuel injection device 10 that directly injects fuel into the combustion chamber 3 without including the fuel injection device 10 in the intake port 5. The fuel injection device 10 is provided adjacent to the spark plug 8 at the top of the combustion chamber 3. Since the main configuration is the same as that of the above-described embodiment of FIG. 1 and the like, the following description will focus on differences from those embodiments.

  In the engine of this embodiment, the attachment hole 11 for the fuel injection device 10 that opens into the intake port 5 and the enlarged diameter portion 12 around the attachment hole 11 are not provided, and the intake port 5 is located on the upstream side. Except for the vicinity of the heat-insulating material supply hole 25 and the vicinity of the intake valve 2 close to the combustion chamber 3, the cross-sectional circular shape or the elliptical cross-sectional shape has a flat inner surface, and the cross-sectional portion is linear or curved. It extends in the shape to do. As in the above-described embodiment, the cross-sectional shape of the intake port 5 and the direction in which the intake port 5 extends are determined according to the engine specifications.

  The heat insulating member 20 is formed except for the vicinity of the intake valve 2, and the shape thereof is a cylindrical portion 23 having a predetermined thickness along the entire inner circumference of the intake port 5 in a region upstream of the vicinity of the intake valve 2. ing.

  The heat insulating member 20 includes a first protruding portion 26 that protrudes into the heat insulating material supply hole 25. The first protruding portion 26 is formed integrally with the cylindrical portion 23 and is in a state of extending into the heat insulating material supply hole 25 as in the above-described embodiment. The first protrusion 26 enhances the degree of close contact between the heat insulating member 20 and the inner surface of the intake port 5 and prevents the heat insulating member 20 from moving.

  Here, the point z in FIG. 5 indicates that the distance from the downstream end or the upstream end is half that of the total length L of the heat insulating member 20 in the intake flow direction in the intake port 5. It is a central position corresponding to L ″. In order to reduce the thermal influence from the combustion chamber 3, it is desirable that the first protrusion 26 is as upstream as possible, and in particular, upstream from the central position z. It is more preferable to exist in the region.

DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Intake valve 3 Combustion chamber 4 Intake valve hole 5 Intake port 6 Upstream end surface 10 Fuel injection apparatus 11 Mounting hole 12 Expanded diameter part 20 Thermal insulation member 22 Second protrusion 23 Cylindrical part 25 Insulation material supply hole 26 1st protrusion part 26a Upstream side contact part 26b Lower surface 26c Downstream side contact part 30 Intake manifold 31 Inner manifold internal passage 32 Flange part 32a Inner manifold end surface

Claims (7)

An intake port provided in the cylinder head of the engine and connected to the combustion chamber;
A heat insulating member disposed along the inner surface of the intake port;
A heat insulating material supply hole that opens into the intake port;
With
The heat insulating member includes a first protrusion extending into the heat insulating material supply hole,
Engine intake passage structure comprising A mounting hole that opens into the intake port and through which the fuel injection device is inserted;
With
The mounting hole is disposed in an enlarged diameter portion formed in the intake port,
The heat insulating member is a second protrusion disposed along the enlarged diameter portion,
The engine intake passage structure according to claim 1, further comprising: 3. The intake passage structure for an engine according to claim 1, wherein the first protrusion includes an upstream contact portion that contacts an inner wall surface upstream of the heat insulating material supply hole in the intake flow direction. The engine intake passage structure according to claim 2, wherein the attachment hole and the heat insulating material supply hole are arranged on opposite sides of a center portion of a flow path cross section of the intake port. The engine intake passage structure according to claim 2 or 4, wherein an opening of the heat insulating material supply hole into the intake port is located upstream of an opening of the mounting hole into the intake port. The engine intake passage structure according to any one of claims 1 to 5, wherein the heat insulating material supply hole is provided perpendicular to a flow direction connecting the upstream side and the downstream side of the intake port. The engine intake passage structure according to claim 6, wherein the first protrusion includes a downstream contact portion that contacts an inner wall surface of the heat insulating material supply hole on the downstream side in the intake flow direction.

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