JPS60132017A - Engine exhaust pipe installing construction - Google Patents

Abstract

PURPOSE:To secure general-purpose properties of an engine and prevent a connected part from suffering from imoderate force by connecting an exhaust port opening to an exhaust pipe by means of a curved exhaust connecting pipe and symmetrically forming the mounting seats for said exhaust connecting pipe. CONSTITUTION:A pair of exhaust ports 6 are provided on a cylinder head 5 on the upper part of the combustion chamber 2 of a cylinder 1, a nearly eliptical stepped part 7 is formed surrounding the port opening 6a formed on the side of the head 5, and the upper course side opening 8a of the exhaust connecting pipe 8 is fitted into the stepped part 7 through an annular gasket 9. A bracket 10 is formed on the outside of, and near the opening 8a of the exhaust connecting pipe 8 in an integrated form, and is connected to the cylinder head 5 through a clamping member 11. These bracket 5 and member 11 are symmetrically placed with respect to the center line of the opening 8a. The exhaust connecting pipe 8 is curved nearly at a right angle, has a stepped part 15 on its lower course side, and an exhaust pipe 16 of a double-pipe structure is fitted in the stepped part 15.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an exhaust pipe attachment structure suitable for motorcycle engines and the like.

(Prior Art) When connecting an exhaust pipe to an exhaust port provided in the cylinder head of a motorcycle engine, a configuration is generally adopted in which a metal fitting is provided at the upstream end of the exhaust pipe and the connection is made directly. There is. However, because exhaust pipes usually have a double pipe structure, it is difficult to bend or bend them strongly. Therefore, a configuration is often adopted in which the cylinder head is modified so that the opening direction of the exhaust port is inclined toward the exhaust pipe side. However, when such a configuration is adopted, the position of the exhaust pipe relative to the engine is limited (for example, limited to either the left or right side), which reduces the degree of freedom in design and reduces the versatility of the engine, especially the versatility of the cylinder head. There is a problem where the data is lost.

In a V-type motorcycle engine in which each cylinder is arranged in a longitudinally inclined position, the exhaust port of the front cylinder is provided at the front of the cylinder head, and the exhaust port of the rear cylinder is located at the rear of the cylinder head. Generally, it is provided.

In this case, strain is likely to occur particularly at the exhaust pipe connection point of the rear cylinder near the exhaust pipe extending rearward. In addition, if the opening direction of the exhaust port is tilted toward the exhaust pipe side, it will no longer be possible to make the cylinder head the same shape between the front and rear cylinders.
It is inevitable that they will need to be manufactured using separate molds, which will increase costs.

(Objective of the Invention) To maintain a large degree of freedom in design by not restricting the position of an exhaust pipe with respect to the engine, and to ensure versatility of the engine, especially the versatility of the cylinder head. Also, even in the case of a V-type engine, make sure that no strain occurs at the connection point between the exhaust boat and the exhaust pipe.

(Structure of the Invention) Engine exhaust pipe installation is a structure that requires the following items as essential requirements.

(a) Open the exhaust boat on the side of the cylinder head.

0)) Connect the exhaust boat opening and the upstream end of the exhaust pipe with a curved exhaust connecting pipe.

(0) When attaching the exhaust connecting pipe to the cylinder head, the seat is formed symmetrically so that the direction of attaching the exhaust connecting pipe can be changed from left to right.

(Embodiment) FIG. 1 is a partial horizontal cross-sectional view showing a case where the exhaust pipe mounting structure according to the present invention is adopted in a single-cylinder motorcycle engine, with arrow F pointing forward. The cylinder 1 has a combustion chamber 2 inside, and a chain chamber 8 extending in the vertical direction on the right side. A cam chain 4 that connects a lower crankshaft (not shown) and an upper valve opening/closing cam is disposed within the chain chamber 8 . A pair of exhaust boats 6 are provided in the cylinder head 5 above the combustion chamber 2, and a boat opening 6a is formed in the side surface of the head 5. Further, a substantially oval step portion 7 extending in the left-right direction surrounding the opening 6a is formed on the side surface of the spatula 5, and the upstream port 8a of the exhaust connecting pipe 8 (made of cast iron, for example) is attached to the step portion 7 with an annular gasket. 9 and are fitted while maintaining airtightness.

On the outside near the opening 8a of the tube 8, as shown in FIG.
The brackets 10 at the locations are integrally formed and are each fixed to the cylinder head 5 (FIG. 1) by fastening members 11. Each bracket 10 and member 11 are arranged symmetrically with respect to the center line A of the opening 8a, and are aligned with the imaginary line 8''
Even when the tube 8 is disposed in the direction shown in FIG. As shown in FIG. 1, the member 11 is composed of a stud bolt 18 whose one end is screwed into the boss portion 12 of the cylinder head 5, and a cap nut 14 which is screwed into the tip of the bolt 18 passing through the bracket 10. has been done.

The exhaust connecting pipe 8 is curved to the right at a substantially right angle, and has an annular stepped portion 15 that widens at its downstream end. Stepped part 1
A cylindrical member 28 welded to the upstream end of the exhaust pipe 16 is fitted into the exhaust pipe 5 with a gasket 17 in between while maintaining airtightness. The exhaust pipe 16 has a double pipe structure, and the member 2
A metal fitting 18 is in contact with the downstream end surface of the exhaust pipe 16 and fits into the exhaust pipe 16 with a slight play, and a nutadport 20 is fitted into a boss portion 19 formed on the metal fitting 18. One end of the nut bolt 20 is screwed into a boss 21 formed at the downstream end of the pipe 8, and the other end passes through the boss 19, and a cap nut 22 is screwed onto the tip, thereby allowing exhaust gas to be removed. The connecting pipe 8 and the exhaust pipe 16 are tightly connected while maintaining airtightness.

Note that the exhaust gas discharged from the exhaust boat 6 is discharged to the exhaust pipe 16 via the exhaust connecting pipe 8. When the engine shown in FIG. 1 is mounted on a motorcycle in which the exhaust pipe 16 is placed on the left side, the pipe 8 is placed at a position of 8° on the imaginary line in FIG. 2, and the cylinder head 5 ( Figure 1)
It should be fixed to . When used in an N-type engine, the pipes 8 of one cylinder are fixed in the direction of the solid line and the pipes 8 of the other cylinder are fixed in the direction of the imaginary line 8' with respect to the cylinder heads 5 of the same shape. This allows the exhaust pipe 16 to be placed on the same side, either the left or right side of the vehicle.

(Effect of the invention) The exhaust boat and the exhaust pipe are connected by the exhaust connecting pipe, and the exhaust connecting pipe is attached to the cylinder head by the seat (for example, the step 7).
, boss portion 12, etc.) are formed bilaterally symmetrically, and the mounting direction of the exhaust connecting pipe can be changed from left to right. , there is a large degree of freedom in design, and the appearance can be easily changed.

(To) The same is true whether the exhaust pipe is on the left or right side of the engine.
cylinder head can be used, making it possible to share the cylinder head between multiple models.
It is possible to improve the versatility of the engine and reduce costs.

(Q) When used in a V-type engine, cylinder heads of the same shape can be used for both front and rear cylinders, which not only reduces costs, but also eliminates the need for strongly curved exhaust pipes. There is no strain in connection with the port.

(Another Embodiment) (a) The present invention can also be applied to a multi-cylinder engine by making the exhaust connecting pipe 8 a manifold type and by making the attachment of the pipe 8 to the cylinder head 8 symmetrical.

(c) The exhaust connecting pipe 8 is not limited to being curved at a substantially right angle; depending on the position of the exhaust pipe 16, the more acutely angled side portions may be curved toward an obtuse angle.

[Brief explanation of drawings]

Claims (1)

[Claims] The exhaust port is opened on the side of the cylinder head, and the exhaust boat opening and the upstream end of the exhaust pipe are connected by a curved exhaust connecting pipe, and the seats are formed symmetrically to attach the exhaust connecting pipe to the cylinder head. The structure of the engine exhaust pipe installation is characterized by the fact that the direction of the exhaust connecting pipe can be changed from left to right.