JPH07305627A - Extension pipe structure for engine exhaust - Google Patents

Abstract

PURPOSE:To greatly reduce an engine exhaust sound by adding a muffling function to an extension pipe and also to greatly simplify the structure of the extension pipe having the muffling function in a system in which engine exhaust discharged from the outlet of a muffler is discharged to the outside air through the extension pipe. CONSTITUTION:An extension pipe 8 is formed of a pipe material having its uniform inner diameter a muffling chamber S is formed therein by providing a pair of upper and lower partitioning plates 9 and 10 at a preset interval and a muffler communicating port 10a continuing to the outlet pipe 6a of a muffler 6 is formed on the lower partitioning pipe 10 while an outside air communicating port 9a continuing to the outside air is formed on the upper partitioning plate 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine exhaust extension pipe structure provided in an engine-equipped vehicle such as a construction machine.

[0002]

BACKGROUND OF THE INVENTION Generally,
In an engine-equipped vehicle such as a construction machine, the exhaust gas of the engine is configured to be released to the outside air via a muffler. It is known that the muffling effect of the muffler is generally increased in proportion to the muffler capacity. However, in the case where the muffler is arranged in the engine room, the muffler is limited due to space restrictions. It is difficult to increase the capacity, and as a result, it is not possible to suppress the sound sufficiently. Therefore, it is proposed to add an auxiliary silencer to the outside of the vehicle to reduce the exhaust noise, but in this case, two silencers are required, which is not acceptable as a significant cost increase. , There was a fear that the appearance of the auxiliary muffler would be impaired.

[0003]

SUMMARY OF THE INVENTION The present invention was devised with the object of providing an extension pipe structure for engine exhaust capable of eliminating these drawbacks in view of the above-mentioned circumstances, and it is a silencer. When the engine exhaust discharged from the outlet of the container is discharged to the outside air through the extension pipe, the extension pipe is formed of a pipe material having a substantially uniform inner diameter, and the inside thereof has a predetermined interval in the exhaust direction. A pair of partition plates form a muffling chamber, and the partition plate on the upper side in the exhaust direction is
The silencer communication port communicating with the outlet of the silencer is formed, while the partition plate on the lower side in the exhaust direction is formed with an outside air communication port communicating with the outside air. With this configuration, the present invention does not allow a sound deadening function to be added to the extension pipe to significantly improve the sound deadening performance, and the structure of the extension pipe having the sound deadening function can be significantly simplified. Is.

[0004]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, one embodiment of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 denotes a hydraulic excavator which is an example of a vehicle equipped with an engine, and the hydraulic excavator 1 includes a crawler type traveling unit 2, a revolving unit 3 which is rotatably supported on an upper portion of the traveling unit 2, and a revolving unit 3. The working part 4 is connected to the front end of the part 3 and the like.
It is hydraulically operated by the power of an engine (not shown) mounted on the rear part of the vehicle, but the basic configuration of each of them is the same as the conventional one.

Reference numeral 5 denotes an engine room in which the engine is arranged. In the engine room 5, a muffler 6 for muffling the exhaust sound of the engine is arranged. The outlet pipe 6a provided in the upper portion projects outward from the opening 7a formed in the top plate 7 of the engine room 5.

Numeral 8 is an extension pipe for discharging the engine exhaust gas discharged from the outlet pipe 6a to the outside. The extension pipe 8 is
The opening 7 is formed of a pipe material having a uniform inner diameter.
Although it is fitted and assembled in the vertical direction to the peripheral tubular portion 7b of a, an inclined portion 8b that is inclined approximately 45 ° with respect to the vertical portion 8a is integrally welded to the upper end portion thereof. ing.

Further, 9 and 10 are a pair of upper and lower partition plates which are provided inside the extension pipe 8 (vertical portion 8a) at a predetermined interval, and between the partition plates 9 and 10 there is a silencing chamber. Although the S is formed, the muffler chamber S has a muffler communication port 10 a formed in the lower partition plate 10.
While communicating with the outlet pipe 6a via the outside air, it communicates with the outside air through the outside air communication port 9a formed in the upper partition plate 9.

Furthermore, reference numeral 11 denotes an outside air communication pipe which is assembled in the outside air communication port 9a in a penetrating manner, and the outside air communication pipe 11 functions as a throttle pipe member for setting the exhaust cross-sectional area from the muffling chamber S. However, the outside air communication pipe 11 also functions as a shielding member for rainwater, mud, dust, or the like that linearly enters the muffling chamber S through the exhaust gas discharge port 8c of the extension pipe 8. ing.

By the way, when the outside air communication pipe 11 is provided, an annular groove is formed in the upper surface of the upper partition plate 9, so that rainwater or the like may be accumulated in this area. In the above, since the water drainage hole 8d is formed at a predetermined position of the extension pipe 8 (a position immediately above the upper partition plate 9), water is accumulated in the concave groove to corrode the extension pipe 8 or water from the concave groove. It is possible to surely avoid the inconvenience that water overflows into the silencing chamber S and the muffler 6 and water invades.

In the embodiment of the present invention constructed as described above, the engine exhaust is silenced by the silencer 6 and then released to the outside air through the extension pipe 8. The exhaust gas discharged from the outlet pipe 6a of No. 6 passes through the silencer chamber S having a larger cross-sectional area than the outlet pipe 6a, and is then released to the outside air through the outside air communication pipe 11 having the smaller cross-sectional area than the silencer chamber S. It will be.
That is, in the sound deadening chamber S, an enlarged portion and a reduced portion (discontinuous points of the cross-sectional area) of the cross section are formed, so that a reflection phenomenon of a sound wave occurs, and the exhaust sound is generated based on the interference action of the reflected sounds. Will be attenuated.

As described above, according to the present invention, the extension pipe 8 for discharging the exhaust gas of the silencer 6 to the outside air.
In addition, since the exhaust noise muffling function is added, a sufficient muffling effect can be obtained without increasing the capacity of the muffler 6 or adding an additional auxiliary muffler outside the machine.

Moreover, since a sound deadening function can be added to the extension pipe 8 having a uniform inner diameter by providing a pair of upper and lower partition plates 9 and 10, the extension pipe 8 itself is deformed to form the sound deadening chamber S. Although the manufacturing cost can be remarkably reduced as compared with the case where it is formed, since the appearance of the extension pipe 8 is not changed, there is no inconvenience of impairing the appearance of the machine body.

Further, the outside air communication pipe 11 provided on the upper partition plate 9 passes through the exhaust gas discharge port 8c of the extension pipe 8 and rainwater which linearly enters the silencing chamber S,
Since it also functions as a shielding member for mud, dust, etc., rainwater,
It is possible to effectively prevent mud, dust, and the like from entering the muffling chamber S, or even to prevent the muffler 6 from entering, thereby preventing the performance of the muffler 6 from deteriorating.

When the outside air communication pipe 11 is provided, an annular groove is formed on the upper surface of the upper partition plate 9, so that rainwater or the like may collect in that portion. In the above, since the water drainage hole 8d is formed at a predetermined position of the extension pipe 8, water is accumulated in the concave groove to corrode the extension pipe 8, or water overflows from the concave groove and the muffler chamber S or the muffler. It is possible to surely avoid the inconvenience that water invades up to 6.

[0015]

In summary, since the present invention is constructed as described above, the engine exhaust discharged from the muffler outlet is discharged to the outside through the extension pipe. Since a sound deadening chamber is formed inside the housing by the pair of partition plates, a sound deadening function can be added to the extension pipe to significantly improve the sound deadening performance.

Further, the extension pipe is
It has a very simple structure in which a pair of partition plates are provided inside a pipe material with a substantially uniform inner diameter, so the manufacturing cost is significantly reduced compared to the case where the silencing chamber is formed by changing the pipe inner diameter. Moreover, since it does not affect the external appearance of the extension pipe, it is possible to avoid the inconvenience of impairing the external appearance of the machine body.

Further, when an outside air communication pipe is provided at the outside air communication port formed on the partition plate on the lower side in the exhaust direction to block the path directly facing the muffler chamber from the exhaust emission port of the extension pipe, rainwater, mud, It is possible to effectively prevent dust and the like from entering the muffling chamber.

By the way, when the outside air communication pipe is provided, a recess is formed on the partition plate on the lower side in the exhaust direction, and rain water or the like may be collected in the recess, but a drain hole is formed in the extension pipe. By doing so, it is possible to drain the water that has accumulated in the recess, and thus avoid the inconvenience that the accumulated water corrodes the extension pipe and the water that overflows from the recess enters the muffler or muffler. it can.

[Brief description of drawings]

FIG. 1 is a side view of a hydraulic excavator.

FIG. 2 is a cross-sectional view showing an extension pipe structure.

FIG. 3 is a sectional view of the same as a conventional example.

[Explanation of symbols]

 1 hydraulic excavator 5 engine room 6 silencer 8 extension pipe 8a vertical part 8b inclined part 8c discharge port 8d drain hole 9 upper partition plate 9a outside air communication port 10 lower partition plate 10a silencer communication port 11 outside air communication pipe S silencer chamber

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takahiro Noguchi 4-10-1 Yoga, Setagaya-ku, Tokyo Inside New Caterpillar Mitsubishi Co., Ltd. (72) Inori Yasunori Ueda 4-1-1, Yoga, Setagaya-ku, Tokyo Inside New Caterpillar Mitsubishi Corporation

Claims (3)

[Claims] 1. When the engine exhaust discharged from the outlet of a silencer is discharged to the outside air through an extension pipe, the extension pipe is formed of a pipe material having a substantially uniform inner diameter, and the exhaust gas is exhausted inside the exhaust pipe. A pair of partition plates with a certain interval in the direction to form a muffling chamber, and the partition plate on the upper side in the exhaust direction has a muffler communication port leading to the outlet of the muffler, while the partition plate on the lower side in the exhaust direction. The extension pipe structure for engine exhaust is characterized in that an outside air communication port that communicates with the outside air is formed on the inside. 2. The outside air communication port according to claim 1, wherein the outside air communication port formed on the partition plate on the lower side in the exhaust direction is provided with an outside air communication pipe that blocks a path that directly faces the muffler chamber from the exhaust emission port of the extension pipe. Extension pipe structure for engine exhaust, which is characterized by 3. The extension pipe structure for engine exhaust according to claim 2, wherein the extension pipe is provided with a drain hole for discharging water accumulated on the partition plate on the lower side in the exhaust direction.