JPH11107868A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine on which an intake manifold is reliably mounted with high durability and excellent workability while size in the direction of height is suppressed to a low value, in the case of an intake manifold being connected to the upper surface position of an internal combustion engine body. SOLUTION: A second flange part 82 on the upper surface side of an auxiliary port member 80 is inclined toward the outside in the direction of the width of a cylinder head 4, the third flange part 86 of an intake manifold 84 is orthogonally to face connected to the inclining second flange part. The intake manifold is folded in the vicinity of a third flange part at the outside in the direction of width of the cylinder head, namely, the manifold is bent toward the inclination direction of the second flange part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine mounted on a vehicle, and more particularly, to a technique for disposing an intake pipe.

[0002]

2. Related Background Art In recent years, in a spark ignition type internal combustion engine mounted on a vehicle, fuel is directly injected into a combustion chamber in place of a conventional intake pipe injection type in order to reduce harmful exhaust gas components and improve fuel efficiency. Various types of in-cylinder injection gasoline engines (internal combustion engines) have been proposed.

[0003] In such a direct injection gasoline engine, for example, an intake port is formed as a port extending upright in the cylinder head. Vortices can be generated. And
In the direct injection gasoline engine as described above, the intake port member is provided upright on the upper portion of the cylinder head without interfering with the valve mechanism, and an intake manifold is connected to the upper end of the intake port member. I have. That is, the intake port member and the intake manifold are connected at an upper surface position of the engine body. Specifically, a flange portion is formed in parallel with the upper surface of the cylinder head for opposition to the connection portion between the intake port member and the intake manifold for reasons such as easiness of processing. And are joined by a plurality of mounting bolts (fastening members).

[0004]

By the way, in a bonnet type vehicle such as a passenger car in which an engine is mounted in an engine room at the front of the vehicle, it is necessary to widen the field of view of the occupant as much as possible and to lower the position of the engine hood. The intake manifold connected to the top surface of the engine is largely bent to the side of the engine while securing clearance with the engine hood, thereby keeping the engine height low.

[0005] However, if the intake manifold is greatly bent as described above, when the intake manifold vibrates during running of the vehicle, stress is locally concentrated at the bending point, and the intake manifold is fatigued, resulting in poor durability. There is. Also, when the intake manifold is greatly bent, the flange portion formed on the bent side of the intake manifold is hidden by the intake manifold, so that it is difficult to dispose a plurality of mounting bolts at equal intervals and to attach the mounting bolts. However, there is also a problem that the effective arrangement space becomes narrow, and the number of used mounting bolts and the diameter are limited. If the mounting bolts are not evenly arranged and the number and diameter are limited, the joining strength between the intake port member and the intake manifold decreases, the holding force of the intake manifold decreases, and the seal between the intake port member and the intake manifold It is not preferable because the properties are impaired. In particular, in an engine such as a direct injection gasoline engine capable of lean burn operation, a large amount of intake air is required during the lean burn operation, so that the cross-sectional area of the intake passage of the intake manifold is large and the intake manifold is wide. Therefore, the area of the flange portion permitted for one cylinder is smaller for an engine with a larger displacement, and this problem is conspicuous.

Further, depending on the position of the mounting bolt, there is a problem that the intake manifold and the fastening tool interfere at the time of fastening, and the workability of fastening the mounting bolt is poor. The present invention has been made based on the above-described circumstances, and an object of the present invention is to make it possible to reliably attach an intake manifold to an internal combustion engine body with high durability and good workability while keeping the height dimension small. An internal combustion engine is provided.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, the second flange portion formed on the upper surface side of the auxiliary port member is directed outward in the width direction of the cylinder head. It is inclined downward. The third flange portion of the intake manifold is connected to the inclined second flange portion, and the intake manifold is directed outward in the width direction of the cylinder head near the third flange portion, that is, in the inclination direction of the second flange portion. Is bent.

Therefore, in the present invention, the height of the internal combustion engine is suppressed by bending the intake manifold, but in this case, the intake manifold itself does not need to be bent so much, and therefore, the intake manifold is not required when the vehicle is running. Even if the manifold vibrates, stress is not locally concentrated at the bending point, and the durability of the intake manifold is ensured. In addition, since the second flange portion is inclined, the effective area of the third flange portion is increased, and the arrangement of the fastening member is improved.

According to the second aspect of the present invention, the second flange portion and the third flange portion are connected by fastening a fastening member in a direction perpendicular to the surface. Therefore, since the angle of the bending of the intake manifold with respect to the third flange portion is relatively large, it is possible to dispose the fastening member as close as possible to a portion of the third flange portion on the bent side of the intake manifold. It is possible, and it is possible to arrange a plurality of fastening members at equal intervals as much as possible. Further, it is possible to secure the insertion space for the tool and to improve the fastening workability.

Therefore, the bonding strength between the second flange portion and the third flange portion is made sufficient, and the second flange portion and the third flange portion are connected to each other.
Sealability between the flange portions is ensured.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. Referring to FIG. 1, there is shown a longitudinal sectional view of an internal combustion engine according to the present invention mounted in an engine room at a front portion of a vehicle. Hereinafter, the internal combustion engine according to the present invention will be described with reference to FIG.

As shown in FIG. 1, the internal combustion engine according to the present invention is, for example, a four-cylinder four-cylinder SOHC (single overhead camshaft) type direct injection gasoline engine. Is configured to be able to inject fuel directly into the cylinder. The fuel can be injected not only in the intake stroke but also in the compression stroke.

As shown in FIG. 1, an SOHC type direct injection gasoline engine (hereinafter simply referred to as an engine) 1 is mounted on a cylinder block 2 via a gasket (not shown), similarly to a normal gasoline engine. The cylinder head 4 is fixed by bolts or the like. A rocker cover 6 made of, for example, a steel plate is mounted on the cylinder head 4 and is also fixed with bolts or the like. More specifically, an endless seal member 7 is attached to the periphery of the rocker cover 6, that is, the rocker cover 6 is attached to the cylinder head 4 via the seal member 7.
Thereby, the airtightness of the rocker chamber 6a, which is the internal space of the rocker cover 6, is ensured.

As shown in FIG. 1, a piston 12 is inserted into a cylindrical cylinder 10 of the cylinder block 2. This piston 12 is connected to a connecting rod 14
And slides in the cylinder 10 according to the rotation of the crankshaft to reciprocate. In addition, on the top surface of the piston 12,
Although a cavity 16 which is a hemispherical depression is formed, a detailed description is omitted here.

On the other hand, a fuel injection valve (injector) 22 is provided in the cylinder head 4 so as to directly inject fuel toward a combustion chamber 20 defined by the lower surface of the cylinder head 4 and the top surface of the piston 12. Is provided.
The allowable fuel injection pressure of the fuel injection valve 22 is set to a high pressure (e.g., during the compression stroke in which the pressure in the combustion chamber 20 becomes high). 50 kgf / cm ² or more).

The cylinder head 4 has an intake port 34 branched in a Y-shape. Specifically, a pair of intake ports 30, 30 are located on the lower surface of the cylinder head 4 on one side of a base surface including the longitudinal axis of the engine 1 connecting the cylinder axis X and the central axis of each cylinder. The lower end (one end) of each of the pair of branch port portions 34a, 34a is formed with the pair of intake ports 3a.
At 0 and 30, the opening faces the combustion chamber 20, while the upper end forms one port portion 34 b in the cylinder head 4.

The cylinder head 4 also has Y
An exhaust port 36 branched in a letter shape is formed. Specifically, a pair of exhaust ports 32, 32 are formed on the lower surface of the cylinder head 4 on the other side of the base surface, and the exhaust port 36 is formed by a pair of branch port portions 36a, 36a.
One end of the cylinder head 4 is open at the pair of exhaust ports 32, 32 facing the combustion chamber 20, while the other end is open at the side surface of the cylinder head 4.

The intake ports 30, 30 have branch port portions 34, respectively.
a, 34a are provided with a pair of intake valves 40, 40 for communicating and blocking between the combustion chamber 20 and the exhaust port 3.
A pair of exhaust valves 42, 42 for communicating and shutting off the communication between the branch ports 37, 37 and the combustion chamber 20 are provided in the ports 2, 32. As shown in the drawing, the intake valves 40, 40 and the exhaust valves 42, 42 are connected to the intake ports 40, 40 and the exhaust port 4 respectively.
Similarly to the positional relationship between the cylinder heads 2 and 42, the cylinder head 4 is provided so as to sandwich the base surface. These intake valves 40, 40 and exhaust valves 42, 42 are not special,
It is commonly used in internal combustion engines.

The engine 1 is mounted on the cylinder head 4.
A single camshaft 60 is rotatably supported along the center line in the longitudinal direction. Specifically, the camshaft 60 is supported on a plurality of shaft support portions 62 formed between the cylinders and at both ends of the cylinder head 4, and further, cam caps 64 provided corresponding to these support portions 62 are provided. And rotatably supported by the cylinder head 4. In addition, a reinforcing plate 65 is passed over each cam cap 64, and each cam cap 64 and the plate 65 are fastened and fixed to the support portion 62 by a pair of bolts.

The camshaft 60 has a pair of cam portions 60a, 60a and 60a so as to correspond to the intake valves 40, 40 and the exhaust valves 42, 42, respectively.
b is formed. And, these cam parts 60a, 6
A pair of rocker arms 70, 70 are provided between the intake valve 40a and the intake valves 40, 40, and a rocker arm 72 having a Y-shape as viewed from the cylinder axis X direction is provided between the cam portion 60b and the exhaust valves 42, 42. ing.

More specifically, as shown in FIG. 3, a rocker shaft 74 and a rocker shaft 76 are supported by the cam cap 64 in parallel with the camshaft 60.
The rocker arms 70, 70 and the rocker arm 72 are swingably supported by the rocker shaft 74 and the rocker shaft 76, respectively. Therefore, the camshaft 60
Is rotated, the rocker arms 70 and 72 follow the shapes of the cam portions 60a and 60b and the rocker shafts 74 and 7 are moved.
As a result, the intake valves 40 and 40 and the exhaust valves 42 and 42 open and close against the urging force of the coil spring.

The cylinder head 4 includes a combustion chamber 20.
The spark plug 100 is mounted through the guide tube 104 so that the spark generating portion protrudes at substantially the center of the spark plug, that is, the ignition position where the air-fuel mixture in the combustion chamber 20 can be burned most effectively. An ignition coil 106 for supplying a high-voltage current to the ignition plug 100 is provided on the upper surface of the ignition plug 100.

The upper surface of the rocker cover 6 is extended integrally with the rocker cover 6 along the longitudinal center line of the engine 1 and between the ignition coil 106 and an intake manifold 84 described later. Thus, a PCV-breather chamber 110 is formed. PCV-breather room 11
0 indicates that the cylinder 10 and the piston 1
2 is separated (gas-liquid separation) of unburned fuel leaking from the gap between the fuel cell 2 and the lubricating oil component in the blow-by gas, and only the fuel component is supplied to the intake system.

Further, as shown in FIG. 2, auxiliary port members 80 are mounted on the upper surface of the cylinder head 4 corresponding to each cylinder, and a flange portion (first flange portion) 81 is fixed by bolts or the like. In addition, an auxiliary port 80a is formed inside the auxiliary port member 80. Auxiliary port 80a
The lower end communicates with the intake port 34 while extending toward the upper surface of the rocker cover 6 so as to be gradually separated from the cylinder axis X. The upper end is opened at the upper surface position of the rocker cover 6. Specifically, an opening hole 90 is formed in the upper surface of the rocker cover 6 on one side of the base surface corresponding to each cylinder, and a stepped upper end flange portion (second flange portion) of the auxiliary port member 80 is provided. ) 82 is fitted in the opening hole 90. Actually, an annular sealing member 92 is fitted into the peripheral edge 91 of the opening 90 of the rocker cover 6 in an endless manner, that is, the upper end flange 82 is fitted to the opening 90 through the sealing member 92. I agree.

The flange 82 of the intake manifold 84 (the third flange) is attached to the upper end flange 82 of the auxiliary port member 80.
A flange portion 86 is connected directly to the intake manifold 84 with a plurality of bolts (fastening members) except for a portion overlapping the intake manifold 84 when the upper end flange portion 82 is viewed from the upper surface side of the cylinder head 4. Internal passage 84a
And the auxiliary port 80a communicate with each other. Here, the flange portion 86 of the intake manifold 84 and the auxiliary port member 80
And the upper end flange portion 82 is connected with the seal member 92 interposed therebetween, thereby ensuring airtightness between the internal passage 84a and the auxiliary port 80a and the outside.

The engine 1 is configured to be capable of in-cylinder injection and capable of operating at a lean air-fuel ratio, and requires a large amount of intake air during the lean air-fuel ratio operation. Therefore, the passage cross-sectional area of the intake passage 84a is increased,
The intake manifold 84 is made thick. Further, a large surge tank (not shown) is formed in the intake manifold 84 so as to communicate with the intake passage 84a. Therefore, the intake manifold 84 is relatively heavy as a whole.

The intake manifold 84 is bent near the flange 86 toward the outside in the width direction of the cylinder head 4, that is, toward the side of the engine 1. The height of the engine 1 is kept low. Therefore, in FIG. 1, the engine hood 120, which is the lid of the engine room, is shown by a two-dot chain line. In this manner, the engine hood 120 is arranged at a low position without interference with the intake manifold 84. Therefore, in the vehicle, the space above the engine hood 120 is widened, and the occupant's view is well secured.

The upper end flange 82 of the auxiliary port member 80
The flange portion 86 of the intake manifold 84 will be described in more detail. As shown in FIG.
2 and the flange portion 86 are formed so as to have a predetermined angle α with respect to a horizontal plane orthogonal to the base surface, that is, the upper surface of the cylinder head 4 including the support portion 62. That is, the upper end flange portion 82 and the flange portion 86 are inclined downward toward the outside in the width direction of the cylinder head 4. Here, the predetermined angle α is, for example, an angle formed by the surface of the upper end flange portion 82 with the horizontal plane when the surface of the upper end flange portion 82 is formed to be orthogonal to the axis of the auxiliary port 80a.

Referring to FIG. 2, there is shown a view of the joint portion viewed from the axial direction of the auxiliary port 80a, that is, the direction of arrow A in FIG. 1. Referring to FIG. A view in which a joint portion with the flange portion 86 is viewed from one side of the engine 1, that is, the direction of arrow B in FIG. 1 is shown. Hereinafter, the upper end will be described with reference to FIGS. The operation and effect of the fact that the flange portion 82 and the flange portion 86 are inclined at a predetermined angle α will be described.

As described above, if the intake manifold 84 has a surge tank and is made relatively heavy, the intake manifold 84 vibrates when the vehicle is running, and stress is concentrated at the bending point. However, in the internal combustion engine of the present invention, unlike the above-described conventional case, the amount of bending is reduced, and the degree of concentration of stress is reduced. Therefore, in the internal combustion engine of the present invention, first,
There is a great advantage that the intake manifold 84 has less fatigue and durability.

On the other hand, if the intake manifold 84 is relatively heavy, it is necessary to firmly fix the intake manifold 84 to the auxiliary port member 80. To this end, a plurality (three in this case) of fixing the intake manifold 84 is required. It is preferable that the bolt 85a and the pair of bolts 85b, 85b are arranged so that the intervals are even. However, the intake manifold 84 is bent along the engine hood 120 as described above. Therefore, a portion of the flange portion 86 on the side where the intake manifold 84 is bent, that is, a portion overlapping the intake manifold 84 when the upper end flange portion 82 is viewed from the upper surface side of the cylinder head 4 is hidden by the intake manifold 84. Therefore, normally, the intake manifold 8
No fastening member such as a bolt cannot be arranged in the portion of the flange portion 86 hidden by 4. Further, as described above, since the intake manifold 84 is made thick, there is little effective area as a whole on the flange portion 86, and there are restrictions on the space itself in which the fastening members are provided.

However, in the internal combustion engine of the present invention, while the intake manifold 84 is bent, the flange 8
6 is attached to the auxiliary port member 80 at a predetermined angle α, the bending angle of the intake manifold 84 with respect to the flange portion 86 is relatively large as shown in FIG. The distance D between the maximum width line Y (see FIG. 2) indicating the maximum width position of 84 and the axis Z of the bolt 85b is set to be somewhat large.

Therefore, in the internal combustion engine of the present invention, the head of the bolt 85b is slightly interfered with the maximum width line Y when viewed in the axial direction of the auxiliary port 80a. A pair of bolts 8
Even if 5b and 85b are provided (see FIG. 2), it is possible to prevent the head from interfering with the bent portion of the intake manifold 84 at the time of fastening so that the bolt 85b cannot be inserted into the bolt hole of the flange 86. The Rukoto.

Therefore, in the internal combustion engine of the present invention, as shown in FIG. 2, the pair of bolts 85b, 85b can be arranged with a narrow interval therebetween, and the three bolts 85a and the pair of bolts 85b, 85b are provided. The bolts are preferably arranged on the flange portion 86 so that the intervals are as uniform as possible, though the effective area is small. As a result, the intake manifold 84 has sufficient joining strength and the auxiliary port member 80
Therefore, in the internal combustion engine, the sealing property between the upper end flange portion 82 and the flange portion 86 is improved, and the intake passage 84a and the auxiliary port 80a are fixed.
And the outside, and the airtightness between the rocker chamber 6a and the outside are sufficiently ensured.

When fastening the bolt 85b,
Usually a tool as shown in FIG. 3 (for example, a box wrench)
T is used. When the flange portion 86 has the predetermined angle α and the distance D is increased to some extent,
When the box wrench T is used, the interference between the tip box portion of the box wrench T and the bent portion of the intake manifold 84 is favorably avoided within the range of the distance D as shown in FIG. Therefore, the internal combustion engine of the present invention also has an advantage that the bolt 85b can be fastened with good workability.

The upper end flange portion 82 and the flange portion 8
6 is inclined at a predetermined angle α, so that the area of the flange portion 86 where the bolt 85a is disposed is relatively widened (see FIG. 2). Thereby, the bolt 85a can be arranged so that the flange portion 86 having a small effective area is made as large as possible and has a sufficient margin on the flange 86, and the joining strength particularly with the bolt 85a can be increased. There is also an advantage.

Since the space between the intake manifold 84 and the PCV-breather chamber 110 is widened by inclining the flange portion 86, the box wrench T is connected to the intake manifold 84 and the PCV-breather chamber 110 when fastening the bolt 85a. It can be very easily inserted and removed without interference. That is, it is possible to perform the fastening work with good workability and excellently with respect to the bolt 85a.

[0038]

As described above in detail, according to the internal combustion engine of the first aspect of the present invention, the height of the internal combustion engine can be suppressed by bending the intake manifold.
In this case, the intake manifold itself does not need to be bent so much. Therefore, when the intake manifold vibrates during running of the vehicle, stress is not locally concentrated at the bending point, and durability of the intake manifold can be ensured.

Further, since the second flange portion is inclined, the effective area of the third flange portion can be increased, and the arrangement of the fastening member can be improved. Further, according to the internal combustion engine of the second aspect, since the second flange portion and the third flange portion are connected by the fastening member being fastened in a direction perpendicular to the surface, the bent of the intake manifold with respect to the third flange portion is formed. Since the angle is relatively large, the fastening members can be arranged as close as possible to the bent portion of the intake manifold of the third flange portion, and the plurality of fastening members are arranged at equal intervals as much as possible. Can be set up. Further, it is possible to secure a space for inserting a tool to improve fastening workability.

Thus, the bonding strength between the second flange portion and the third flange portion can be made sufficient, and the sealing property between the second flange portion and the third flange portion can be ensured.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an SOHC type direct injection gasoline engine according to the present invention.

FIG. 2 is a view of a joint portion between an auxiliary port member and an intake manifold as viewed from the direction of arrow A in FIG. 1, and is a diagram showing a state of arrangement of fastening bolts.

FIG. 3 is a view of a joining portion between the auxiliary port member and the intake manifold as viewed from a direction indicated by an arrow B in FIG. 1, and is a diagram illustrating a state of a tool during a fastening operation.

[Explanation of symbols]

 Reference Signs List 1 engine 4 cylinder head 6 rocker cover 20 combustion chamber 34 intake port 80 auxiliary port member 80a auxiliary port 81 flange portion (first flange portion) 82 upper end flange portion (second flange portion) 84 intake manifold 84a internal passage 85a bolt (fastening) Member) 85b bolt (fastening member) 86 flange (third flange) 120 engine hood

Continued on the front page (72) Inventor Masahiro Fujimoto 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation

Claims (2)

[Claims] 1. An intake port communicating with a combustion chamber formed between a lower surface of a cylinder head and a top surface of a piston inserted into a cylinder, and extending in the cylinder head toward an upper surface of the cylinder head. Having an auxiliary port which extends upward in communication with the intake port in series, and a first flange portion at one end is connected to the upper surface of the cylinder head and at the other end is outwardly in the width direction of the cylinder head. An auxiliary port member formed with a second flange portion inclined downward toward the intake port, and an intake passage communicating in series with the auxiliary port therein, and the second flange portion is provided at one end on the downstream side of the intake passage. An intake manifold formed with a third flange portion connected to face and bent outward in the width direction of the cylinder head in the vicinity of the third flange portion. An internal combustion engine characterized by the following. 2. The internal combustion engine according to claim 1, wherein a fastening member is fastened and connected to the second flange portion and the third flange portion in a direction perpendicular to a plane.