JP6155021B2 - Internal combustion engine - Google Patents

Description

  The present invention relates to an internal combustion engine provided with a catalyst device in an exhaust system.

  A cylinder head of a multi-cylinder internal combustion engine has a plurality of exhaust ports. In general, the number of exhaust ports corresponding to the cylinder is opened on a side surface of the cylinder head, and a plurality of exhaust ports are provided on the side surface of the cylinder head. An exhaust manifold to be collected at the collecting outlet is fixed with bolts.

  On the other hand, in recent internal combustion engines, a catalyst device is provided in the exhaust passage to purify the exhaust. However, since the catalyst device is provided with a catalyst inside, it is manufactured separately from the exhaust pipe and joined to the exhaust pipe. I have to. Further, since the catalyst has a property of being activated at a high temperature, it is preferable to provide the catalyst as upstream as possible in the exhaust passage. Therefore, a catalyst device is attached to the outlet of the exhaust manifold portion. However, in order to absorb processing errors and vibrations in a state where the sealing performance is secured, Patent Document 1 discloses a catalyst device via a ball joint device. It is described that the device is attached to the collecting outlet of the exhaust manifold section.

JP 11-336536 A

  Now, since the catalyst device has a certain amount of weight, it needs to be supported firmly. However, in the configuration in which a heavy catalyst device is attached to the tip of the exhaust manifold portion that protrudes from the side surface of the cylinder head as in Patent Document 1, the exhaust manifold must also have high rigidity, so it must be thickened, and the weight There is a risk of an increase. Further, since the exhaust manifold portion must be provided with a bracket for mounting the catalyst device, the structure becomes complicated accordingly.

  In addition, since the exhaust manifold portion protrudes from the cylinder head, the vibration of the cylinder head is amplified at the tip of the exhaust manifold portion. For this reason, the catalyst device may also vibrate greatly. It is also conceivable that a case where the sealing property cannot be ensured even when the apparatus is used.

  On the other hand, an internal combustion engine in which an exhaust collecting passage is integrally formed in a cylinder head or an exhaust block body fixed to the cylinder head has been proposed, but the present invention utilizes such an exhaust collecting passage integrated type internal combustion engine. Thus, it is an object of the present invention to make it possible to attach a catalyst device while ensuring sealing performance.

The present invention is
An exhaust collecting passage that combines a plurality of exhaust ports into one exhaust outlet is formed integrally with the cylinder head or the exhaust block body fixed to the cylinder head.
A gasket and a cylinder that can hold a contact state in a state in which a sealing case is secured even if the catalyst case that opens toward the exhaust outlet and has a catalyst inside is secured to the cylinder head or the exhaust block body even if the relative posture is changed. And is attached through a ball joint device having a portion,
A central tube having an exposed portion protruding outside the cylinder head or the exhaust block body is fitted into an exhaust outlet of the cylinder head or the exhaust block body, and the gasket of the ball joint device is an exposed portion of the central tube. While being fitted from the outside and supported by the cylinder head or the exhaust block body ,
The cylinder part has a flange for attaching to the cylinder head or the exhaust block body, and only a bent part connected to the flange among the cylinder parts is in contact with the gasket, and the cylinder part is bent. There is a gap between the gasket and the cylindrical portion on the catalyst case side with the portion interposed therebetween.

In the present invention, since the catalyst case is mounted close to the cylinder head or the exhaust block body via the ball joint device, the catalyst case is prevented from greatly vibrating and the gasket and the cylindrical portion are in contact with each other. Can be firmly held, thereby ensuring high sealing performance .

Further, since the catalyst case is close to the cylinder head or the exhaust block body, the moment acting on the location of the ball joint device is small, and therefore the support stability of the catalyst case is excellent. As a result, it is possible to eliminate the catalyst case and the bracket and stay that support the exhaust pipe fixed to the catalyst case, and the structure can be simplified accordingly. Further, since the gasket is fitted in the center tube, the gasket can be accurately positioned and the sealing performance can be secured.

  Further, since the catalyst case is close to the cylinder head or the exhaust block body, the exhaust gas ejected from the cylinder head or the exhaust block body immediately reaches the catalyst, so that the activity of the catalyst can be enhanced and the purification performance can be improved.

  In particular, when the catalyst case is arranged in a posture substantially orthogonal to the side surface of the cylinder head or the exhaust block body as in the embodiment, the exhaust gas ejected from the exhaust outlet of the cylinder head or the exhaust block body goes straight toward the catalyst. It is effective in improving the activity of the catalyst. Furthermore, since the entire catalyst case thermally expands evenly compared to when the inlet of the catalyst case is bent in an L shape, for example, the sealing performance of the ball joint device is improved by the thermal expansion. It can also prevent deterioration.

  When the exhaust collecting passage is integrated with the cylinder head or the exhaust block body as in the present invention, the temperature of the cylinder head or the exhaust block body is higher than that of the exhaust manifold system. If it is directly fixed to the body, not only will the catalyst case become high temperature and thermal deformation will increase, but there will also be a risk that cables placed nearby will receive radiant heat and be adversely affected.

  On the other hand, in the present invention, the catalyst case is attached via a ball joint device. Since the catalyst case is attached to the cylinder head or the exhaust block body in a state close to heat insulation, the cylinder head or the exhaust block body. It is possible to remarkably suppress the heat from being transferred to the catalyst case. For this reason, it is possible to suppress problems such as the catalyst case being thermally deformed and the durability being lowered, and the radiation heat of the catalyst case being transmitted to the cables.

It is a plane sectional view of a 1st embodiment. It is a plane section of a 2nd embodiment.

(1). First Embodiment Next, an embodiment of the present invention will be described with reference to the drawings. First, the first embodiment shown in FIG. 1 will be described.

  The present embodiment is applied to a three-cylinder internal combustion engine. For this reason, the cylinder head 1 is formed with three recesses 2 corresponding to the three cylinder bores in the shilling block. Two intake ports 3 and two exhaust ports 4 are opened. A branch intake port 5 and a branch exhaust port 6 communicate with the intake port 3 and the exhaust port 4 respectively. The pair of branch intake ports 5 and the branch exhaust ports 6 respectively include an intake collection port 7 and an exhaust. It communicates with the collective port 8.

  Each intake manifold port 7 is opened from one side surface 1a of the cylinder head 1, and an intake manifold (not shown) for supplying and distributing intake air to each intake port 7 is fixed to one side surface 1a of the cylinder head 1. The On the other hand, each exhaust collecting port 8 is collected in the exhaust outlet 10 via a branch collecting passage 9 formed in the cylinder head 1. Accordingly, the branch collecting passage 9 and the exhaust outlet 10 constitute an exhaust collecting passage 11.

  A cylindrical (or tank-shaped) catalyst case 12 containing the catalyst S is attached to the other side surface 1 b of the cylinder head 1 via a ball joint device 13. The ball joint device 13 includes a gasket (ball portion) 14 disposed on the other side 1 b of the cylinder head 1 and a cylindrical portion 15 that abuts on the gasket 14. Needless to say, the catalyst case 12 has a larger outer diameter than the exhaust outlet 10. The gasket 14 is made of an inorganic material that is slightly elastically deformed (compressed).

While the gasket 14 has a shape in which a part of a ball is cut out into a ring shape, a central cylinder 16 having an exposed portion protruding from the other side 1b of the cylinder head 1 is fitted into the exhaust outlet 10 of the cylinder head 1 by press fitting or the like. The gasket 14 is tightly fitted to the exposed portion of the central cylinder 16 from the outside . Therefore, the gasket 14 is held so as not to be displaced in a concentric state with the central cylinder 16 and is supported by the other side 1 b of the cylinder head 1 . The outer surface 14a of the gasket 14 has an arcuate outward projection (or a tapered shape.).

  On the other hand, the cylindrical portion 15 is fixed to the catalyst case 12 by welding, and thus has a diameter-enlarged portion 15a that fits into the catalyst case 12, and the diameter-enlarged portion 15a has a constriction having substantially the same inner diameter as the exhaust outlet 10. It spreads through the part 15b. Therefore, it can be said that the cylindrical portion 15 also constitutes a part of the catalyst case 12. In other words, the cylindrical portion 15 constituting the ball joint device 13 is formed integrally with the catalyst case 12.

A ring-shaped flange 15 c into which the bolt 17 is fitted is bent at the tube portion 15, and a bent portion (corner portion) 15 d connected to the flange 15 c is in contact with the gasket 14. There is a slight gap between the flange 15c and the cylinder head 1, and the change in the attitude of the catalyst case 12 is allowed. Further, by interposing the compression coil spring 18 between the flange 15 c and the head 17 a of the bolt 17, the flange 15 c is elastically pressed and held toward the cylinder head 1. There is a gap between the gasket 14 and the cylindrical portion 15 on the catalyst case 12 side with the bent portion 15d of the cylindrical portion 15 interposed therebetween.

An exhaust pipe (not shown) is fixed to the end 12a of the catalyst case 12 by welding or flange joining. A plurality of bolts 17 (for example, 3 to 6 bolts) are provided at appropriate intervals along the circumferential direction. The bolt 17 is fully screwed into the cylinder head 1. Instead of using a headed bolt, a stud bolt may be screwed into the cylinder head 1 and fixed, and the spring 18 may be supported by a double nut screwed and fixed thereto . Further, instead of the spring 18, another elastic body can be used.

In the case where an EGR device is provided, the EGR passage may be connected to an appropriate portion (for example, a terminal portion) of the catalyst case 12 .

  As can be easily understood from the drawings, the exhaust gas discharged from each exhaust port 4 is ejected from the exhaust outlet 10 toward the catalyst case 12 through the exhaust collecting passage 11 and purified by the catalyst S before being exhausted. Discharged from. Since the catalyst case 12 is attached to the cylinder head 1, the structure can be simplified to contribute to cost reduction and compactness. Further, since the catalyst case 12 is close to the cylinder head 1, the catalyst case 12 is not greatly touched and moved by vibration. For this reason, even if the catalyst case 12 vibrates to some extent, the gasket 14 and the cylindrical portion 15 can be kept in close contact over the entire circumference, and sealing performance can be ensured.

  In addition, since the support strength of the catalyst case 12 is increased by attaching the catalyst case 12 to the cylinder head 1, it is possible to eliminate the need for a bracket or stay for supporting the catalyst case 12 or the exhaust pipe. Thus, the number of members can be reduced and the cost can be reduced.

  If the center tube 16 is provided as in the present embodiment, the gasket 14 can be accurately positioned, which is more suitable for ensuring sealing performance. The central cylinder 16 may be integrated with the cylinder head 1 or may be attached by screwing if it is a separate member.

  In the present embodiment, the catalyst case 12 is in a posture substantially orthogonal to the other side surface 1 b of the cylinder head 1. In other words, the axis of the catalyst case 12 extends in the exhaust gas ejection direction. For this reason, the exhaust gas ejected from the exhaust outlet 10 directly strikes the catalyst S. For this reason, heat dissipation can be suppressed and purification efficiency can be improved. Further, since the catalyst case 12 is thermally contracted evenly throughout, the cylindrical portion 15 can be kept in close contact with the gasket 14 over its entire circumference. Also in this aspect, the sealing performance can be improved.

(2). Second Embodiment In the second embodiment shown in FIG. 2, the exhaust block body 20 is fixed to the other side 1b of the cylinder head 1 with bolts (not shown), and the catalyst case 12 is attached to the exhaust block body 20. Are attached via a ball joint device 13. An exhaust collecting port 8 and an exhaust collecting passage 11 are integrally formed in the exhaust block body 20 .

  The exhaust block body 20 of this embodiment can be identified with the cylinder head 1, and therefore exhibits the same operational effects as the first embodiment described above. Further, when the exhaust block body 20 is provided as in the second embodiment, there is an advantage that the machining of the cylinder head 1 is facilitated (an EGR passage may be provided on the mating surface between the cylinder head 1 and the exhaust block body 20). Easily realized.)

The present invention can be embodied in various ways other than the two embodiments described above .

  The present invention can actually be embodied in an internal combustion engine. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1 Cylinder head 4 Exhaust port 6 Exhaust branch port 8 Exhaust collecting port 9 Branch collecting passage 10 Exhaust outlet 11 Exhaust collecting passage 12 Catalyst case 13 Ball joint apparatus 14 Gasket 15 Tube part
15c flange
15d Bending portion 16 Center tube 17 Bolt 18 Spring as an example of elastic body S Catalyst

Claims (1)

An exhaust collecting passage that combines a plurality of exhaust ports into one exhaust outlet is formed integrally with the cylinder head or the exhaust block body fixed to the cylinder head.
A gasket and a cylinder that can hold a contact state in a state in which a sealing case is secured even if the catalyst case that opens toward the exhaust outlet and has a catalyst inside is secured to the cylinder head or the exhaust block body even if the relative posture is changed. And is attached through a ball joint device having a portion,
A central tube having an exposed portion protruding outside the cylinder head or the exhaust block body is fitted into an exhaust outlet of the cylinder head or the exhaust block body, and the gasket of the ball joint device is an exposed portion of the central tube. While being fitted from the outside and supported by the cylinder head or the exhaust block body ,
The cylinder part has a flange for attaching to the cylinder head or the exhaust block body, and only a bent part connected to the flange among the cylinder parts is in contact with the gasket, and the cylinder part is bent. On the side of the catalyst case across the part, there is a gap between the gasket and the cylindrical part,
Internal combustion engine.

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