JPH0724581Y2 - Exhaust pipe assembly structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an exhaust pipe collecting portion structure, and more particularly to an exhaust pipe collecting portion structure for reducing abnormal noise generated in the collecting portion.

[Conventional technology]

Generally, in the exhaust system of an automobile, for example, the actual exploitation Sho 63-12822
As disclosed in Japanese Patent No. 4, the exhaust gas from the first exhaust pipe and the second exhaust pipe is collected in the third exhaust pipe.

FIG. 3 shows an exhaust system of this kind. In FIG. 3, reference numeral 11 indicates, for example, a first exhaust pipe for guiding exhaust gas from an engine group located on one side of a V-type internal combustion engine (not shown). On the other hand, reference numeral 13 indicates a second exhaust pipe that guides exhaust gas from the engine group located on the other side.

The first and second exhaust pipes 11 and 13 are gathered in the third exhaust pipe 17 in the gathering portion 15, and the exhaust gas is a catalytic converter.
After passing through 19, the muffler 21 and the main muffler 23, it is discharged into the atmosphere.

4 and 5 show the details of the collecting unit 15,
In the figure, reference numeral 17 is a first exhaust pipe 11 and a second exhaust pipe 13.
3 shows a third exhaust pipe for exhausting exhaust gas after assembling with.

In this collecting portion 15, the first and second exhaust pipes 11 and 13 are
By joining the mating surfaces 25 formed at the ends of these exhaust pipes 11 and 13, respectively, the respective exhaust pipes 11 and 13 are joined.
The holes are assembled so that the intersection angle of the hole cores becomes an acute angle θ, and this collecting portion is connected to the third exhaust pipe 17.

[Problems to be solved by the device]

However, in such a conventional exhaust pipe collecting structure, the exhaust gas of the first exhaust pipe 11 and the exhaust gas of the second exhaust pipe 13 directly collide with each other at the inlet of the third exhaust pipe 17. However, there is a problem that interference is caused, noise is generated, and abnormal noise, so-called burr noise, is generated in the collecting portion 15 due to pulsation of exhaust gas.

As a result of earnest research to solve the conventional problem, the present inventor has found that these noises and abnormal noises are caused by the exhaust gas of the first exhaust pipe 11 and the exhaust gas of the second exhaust pipe 13 being the third. Exhaust pipe
It is due to the turbulent state at the entrance of 17,
It has been found that the generation of noise and abnormal noise can be significantly reduced by changing this turbulent flow state to a laminar flow state rapidly.

The present invention was made on the basis of such findings.
Another object of the present invention is to provide an exhaust pipe collecting portion structure capable of promptly forming a laminar flow state of exhaust gas flowing out from the second exhaust pipe to the third exhaust pipe.

[Means for Solving the Problems]

The exhaust pipe collecting part structure according to the present invention is configured such that the first and second exhaust pipes are joined to each other by joining the mating surfaces formed at the ends of the exhaust pipes. In an exhaust pipe collecting part structure in which the collecting parts are assembled so that the crossing angle thereof is an acute angle, and the collecting part is connected to a third exhaust pipe, the collecting part in the third exhaust pipe is opposite to the collecting part. A rectifying tube with a reduced diameter is arranged on the side.

[Action]

In the present invention, since the rectifying pipe having a reduced diameter is arranged at the collecting portion in the third exhaust pipe, the exhaust gas flowing out from the first and second exhaust pipes to the third exhaust pipe. Is
The rectifying tube causes the laminar flow state to be immediately established.

〔Example〕

The present invention will now be described in detail with reference to an embodiment shown in the drawings.

FIG. 1 shows an embodiment of an exhaust pipe collecting portion structure of the present invention. In the figure, reference numeral 31 indicates, for example, a V not shown.
Shows a first exhaust pipe that guides exhaust gas from an engine group located on one side of a type internal combustion engine, while reference numeral 33 indicates
The second for guiding the exhaust gas from the engine group located on the other side
Shows the exhaust pipe of.

Further, reference numeral 35 denotes a third exhaust pipe for discharging the exhaust gas after the first exhaust pipe 31 and the second exhaust pipe 33 are assembled.

Then, in this embodiment, the first and second exhaust pipes 31, 3
3 joins the mating surfaces 37 formed at the ends of these exhaust pipes 31 and 33, respectively.
The hole cores 39 and 41 of 1,33 are assembled so that the intersecting angle becomes an acute angle θ, and the collecting portion 43 is connected to the third exhaust pipe 35.

Thus, in this embodiment, the collecting portion in the third exhaust pipe 35
On the side of 43, a rectifying tube 45 whose diameter is reduced on the side opposite to the collecting portion 43 is arranged.

The rectifying pipe 45 is, for example, a Venturi pipe, and has a large diameter portion 47 fitted and fixed to the inner circumference of the third exhaust pipe 35, a taper portion 49 following the large diameter portion 47, and the taper portion 49. And a small-diameter portion 51 that follows.

In this embodiment, for example, the straightening pipe 45 has a total length of 45 m.
m, the length of the small diameter portion is 15 mm, the inner diameter of the large diameter portion 47 is 54 mm, and the inner diameter of the small diameter portion 51 is 38 mm.

In addition, in this embodiment, the first and second exhaust pipes 31, 33
The straightening pipe 45 is arranged so that the end surface of the large diameter portion 47 of the straightening pipe 45 is located at the intersection P of the hole cores 39 and 41.

In the exhaust pipe collecting portion structure configured as described above, the first
Exhaust gas from the second exhaust pipes 31 and 33 is collected by the collecting portion 43.
In the third exhaust pipe 35, after passing through the rectifying pipe 45, it passes through a catalytic converter (not shown), a pre-muffler, and a main muffler, and is discharged into the atmosphere.

Thus, in the exhaust pipe collecting portion structure configured as described above, the rectifying pipe 45 having a reduced diameter is disposed on the side of the collecting portion 43 in the third exhaust pipe 35, which is opposite to the collecting portion 43. Since the turbulent exhaust gas flowing from the first and second exhaust pipes 31, 33 to the third exhaust pipe 35 is promptly made laminar in the pipe passing through the rectifying pipe 45, It is possible to significantly reduce the exhaust interference noise (jean noise) compared to the past.

Further, it is possible to significantly reduce the abnormal noise (burr noise) generated in the collecting portion due to the pulsation of the exhaust gas as compared with the conventional case.

Further, in the exhaust pipe collecting portion structure configured as described above, since the resonance and resonance peaks of the exhaust system can be changed by the rectifying pipe 45, abnormal noise (komori sound) in the low frequency range is generated. It is also possible to effectively reduce the occurrence.

FIG. 2 shows the muffling characteristics of the exhaust system shown in FIG. 3, in which the horizontal axis represents the engine speed and the vertical axis represents the sound pressure level. In the case of the previously described embodiment with 45, the wavy line shows the case where there is no rectifying tube in the collecting part.

From this graph, it can be seen that the sound pressure level can be reduced over the entire engine speed range with the exhaust pipe assembly structure including the rectifying pipe 45 of the present invention.

[Effect of device]

As described above, according to the present invention, the rectifying pipe whose diameter is reduced on the side opposite to the collecting portion is arranged at the collecting portion in the third exhaust pipe. There is an advantage that the exhaust gas flowing out to the exhaust pipe can be quickly made into a laminar flow state, and the generation of abnormal noise in the collecting portion can be significantly reduced as compared with the conventional case.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the exhaust pipe collecting portion structure of the present invention. FIG. 2 is a graph showing the sound deadening characteristics of the exhaust pipe collecting portion structure of FIG. FIG. 3 is a system diagram showing a conventional exhaust system. FIG. 4 is a vertical sectional view showing a structure of a conventional exhaust pipe collecting portion. FIG. 5 is a cross-sectional view taken along the line VV of FIG. [Explanation of symbols of main parts] 31 …… First exhaust pipe 33 …… Second exhaust pipe 35 …… Third exhaust pipe 37 …… Mating surface 43 …… Collector 45 …… Rectifying pipe.

Claims (1)

[Scope of utility model registration request] 1. The first and second exhaust pipes are joined to the mating surfaces formed at the end portions of these exhaust pipes, whereby the intersection angle of the cores of the respective exhaust pipes becomes an acute angle. In the structure of the exhaust pipe that is assembled as described above and is connected to the third exhaust pipe, a rectifying pipe having a diameter reduced on the side opposite to the aggregate in the aggregate in the third exhaust pipe. Exhaust pipe assembly structure characterized in that.