JPH0536983Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an exhaust pipe structure for a V-type engine.

BACKGROUND ART In a V-type automobile engine, cylinders are divided into two groups (hereinafter referred to as a first bank and a second bank), and these first bank and second bank are divided into two groups. are arranged in a V-shape.

This type of V-type engine generally has exhaust manifolds assembled together and connected to a silencer pipe in order to make effective use of space when mounted on a vehicle (Japanese Patent Laid-Open No. 60-243317). This muffler pipe is designed to reduce noise caused by exhaust pulsation.

For example, as shown in FIG. 3, an exhaust pipe provided with a sound-deadening cavity has flanges 4 and 5 of communication pipes 1 and 3 connected to a first bank and a second bank (not shown), and communication pipes 1 and 2 are connected to the outside. They are communicated with each other through a cylinder 6, and a silencing cavity 7 is formed inside the cylinder 6. The communication pipes 2 and 3 are communicated with each other by an outer cylinder 8, and the vibrations and vibrations of the communication pipes 1, 2, and 3 are contained inside the outer cylinder 8.
A flexible pipe 9 for absorbing thermal strain etc. is housed.

Problems that the invention aims to solve: However, in the conventional exhaust pipe structure of a V-type engine, the flexible pipe is provided at a position away from the outer cylinder that forms the noise-absorbing cavity, so the volume of the flexible pipe increases. However, there was a problem that the engine became larger.

The present invention was devised to solve these problems, and its purpose is to reduce the size of the exhaust pipe of a V-type engine.

Means for Solving the Problems In order to achieve the above object, the exhaust pipe structure of a V-type engine according to the present invention is configured as follows.

That is, a first exhaust manifold and a second exhaust manifold are attached to the first bank and the second bank of the V-type engine, respectively, and the first exhaust manifold and the second exhaust manifold are connected by a communicating pipe. A silencing cavity is provided in the middle of the communicating pipe, and a flexible member is interposed at the connection portion between the communicating pipe and the silencing cavity.

Effects According to the present invention, exhaust pulsation noise is reduced by the sound-deadening cavity, vibrations, thermal distortion, etc. of the communication pipe are absorbed by the flexible member, and furthermore, the sound-deadening cavity and the flexible member are adjacent to each other. Since the exhaust pipe is located at a certain position, the volume occupied by the exhaust pipe is reduced.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings.

Components in FIG. 1 that are substantially the same as those in FIG. 3 are designated by the same reference numerals.

The cylinders of a V-type engine are provided in a first bank and a second bank arranged in a V-shape.

Figure 1 shows the first bank and second bank of a V-type engine.
It shows the communication pipe (exhaust pipe) that connects the banks.

The flange 4 of the communication tube 1 is connected to a first bank, and the flange 12 of the communication tube 11 is connected to a second bank. The other end of the communication pipe 1 is connected to a large-diameter outer cylinder 13, and a muffling cavity 14 is formed inside the outer cylinder 13 to reduce noise caused by exhaust pulsation. The other end of this outer cylinder 13 is connected to the communication pipe 11 via a flexible disk 15, and vibrations, thermal distortions, etc. of the communication pipes 1 and 11 are absorbed at this connection part.

Stoppers 18 and 19 are provided on the outer cylinder 13 and the communication tube 11 to prevent the flexible disk 15 from shifting. Stopper 18 is
It is formed by bending the end of the outer tube 13 in the inner diameter direction, and the stopper 19 is formed by bending the end of the communication pipe 11 in the outer diameter direction.

Generally, when a V-type engine is mounted horizontally on a vehicle, if the exhaust system layout is such that the exhaust pipes are gathered together behind the engine, the length from the exhaust manifold of each bank to the exhaust pipe collection part will be reduced. It makes a big difference. Therefore, an unpleasant sound is generated due to a component of 2n-1/2 order (n=1, 2, . . . ), which is an intermediate order of explosion, among components due to exhaust pulsation (sound pressure pulsation).

In this embodiment, in order to reduce such unpleasant noises, a muffling cavity is provided upstream of the exhaust pipe collection section. 2.5 of the exhaust noise when a sound deadening cavity is provided
The relationship between the next component and the engine rotational speed is as shown in FIG. As can be seen from FIG. 2, when the silencing cavity is provided, the exhaust noise is reduced over almost the entire range from the low-speed rotation range to the high-speed rotation range, compared to the case where the silencing cavity is not provided.

In this embodiment, vibrations, thermal distortions, etc. of the communication pipes 1, 11 become significant during high-load operation, but these vibrations, thermal distortions, etc. are absorbed by the flexible disc 15. The durability of the communication pipes 1 and 11 is improved.

In addition, the flexible member of the present invention is able to withstand vibrations of the communication pipe,
Any means that absorbs thermal strain etc. is not limited to a flexible disk.

Effects of the Invention As explained above, according to the present invention, since a flexible member is interposed at the connection between the communication pipe and the sound-deadening cavity, a small space can function as both a sound-muffling cavity and a bellows pipe. The exhaust pipe can be made smaller. Furthermore, according to the V-type engine according to the present invention, it is possible to secure a sufficiently large volume of the silencing cavity even if there are restrictions on space on the vehicle.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway schematic configuration diagram showing the exhaust pipe of a V-type engine to which the present invention is applied, Fig. 2 is a graph showing the exhaust noise characteristics when a muffling cavity is provided in the exhaust pipe, and Fig. 3 is a graph showing the exhaust noise characteristics when a muffling cavity is provided in the exhaust pipe. FIG. 2 is a partially cutaway schematic configuration diagram showing a conventional example. 1, 11... Communication pipe, 4, 12... Flange,
13... Outer cylinder, 14... Sound deadening cavity, 15... Flexible disc (flexible member), 18, 19... Stopper.

Claims (1)

[Scope of utility model claims] A first exhaust manifold and a second exhaust manifold are attached to the first bank and the second bank of the V-type engine, respectively, and the first exhaust manifold and the second exhaust manifold are connected by a communicating pipe. 1. An exhaust pipe structure for a V-type engine, characterized in that a flexible member is interposed at a connecting portion between the communication pipe and the noise-muffling cavity in the V-type engine in which a noise-muffling cavity is provided in the middle of a communicating pipe.