JPH032658Y2 - - Google Patents

Description

[Detailed description of the invention] A. Purpose of the invention [Field of industrial application] This invention relates to an exhaust system for an internal combustion engine, such as an outboard motor, which mixes water with exhaust gas.

[Conventional technology]

2. Description of the Related Art In the exhaust pipe of an outboard motor, etc., there is a known system in which seawater or the like is introduced into the exhaust pipe to actively cool the exhaust gas to reduce exhaust noise.

However, this alone is not enough, so it is necessary to combine and combine other silencing elements, but since the exhaust gas and water mix and a large amount of water enters the muffler, the muffler is simply a large-capacity expansion chamber. or
Alternatively, a simple half-dividing board is used as a wall board in multiple stages.

That is, for example, since a resonator has a sealed chamber, a drain hole is required in the case of exhaust gas mixed with water, and a resonance effect cannot be obtained. Even in mufflers that use sound-absorbing materials, water gets in and the effect cannot be utilized, so there is no point in combining them.

[Problem that the invention attempts to solve]

In view of the above points, it is an object of the present invention to provide an exhaust system for an internal combustion engine, which is a water-mixing exhaust pipe and can be combined with various other silencing components.

B. Structure of the invention [Means for solving the problem] In the exhaust system that mixes water with exhaust gas, the exhaust pipe has a hollow double structure, and the exhaust is connected to the inner pipe that communicates with the exhaust port of the internal combustion engine. Water is introduced near the port and mixed with the exhaust gas, and the water flows through the small opening in the inner pipe through the action of the exhaust discharge pressure and the water cutter on the inner pipe before reaching the muffler. This is an exhaust system for an internal combustion engine in which the outer pipe is used as the main water pipe and the inner pipe is used as the main exhaust pipe when leading to the space between the muffler and the muffler, allowing connection to other muffler elements.

[Effect]

Water is introduced into the inner pipe of the hollow double pipe and mixed with the exhaust gas to reduce noise, and the water is used to reduce the noise between the inner and outer pipes by using the exhaust discharge pressure, the drain provided in the inner pipe, and the small opening provided in the inner pipe. By discharging the exhaust gas into the space, the inner pipe can be treated as the main exhaust gas conduit when reaching the muffler, and various mufflers can be connected to this pipe.

〔Example〕

1 is an internal combustion engine, 2 is a muffler, and 3 is an exhaust pipe, an inner pipe 3a and an outer pipe 3b communicating with the exhaust port of the internal combustion engine.
It consists of. 4 is a space between the inner and outer tubes, and 5 is a tube for introducing water such as seawater into the inner tube 3a, which is provided directly below the exhaust port.

A suitable opening 6 such as a punched hole or an elongated hole is made at one or more locations in the exhaust flow direction of the inner pipe 3a, and a drainer is provided at the opening position.

In Fig. 1, the double pipe 3 is bent at the position where the above-mentioned opening 6 is provided, and the bent surface of the inner pipe 3a is used as a draining surface. The portion is discharged through the opening into the space 4 together with the exhaust gas.

FIG. 1 shows an example in which the exhaust downstream end of the outer pipe 3b is connected to the first chamber 7 of the silencer 2 while being open, and the exhaust gas containing water is discharged from the space 4 to the first chamber 7 and is diffused and stirred. Then, it is discharged outside the muffler from the discharge pipe 8 of the muffler 2 which extends to the first chamber. Since the inner pipe 3a downstream of the above-mentioned water discharge position serves as a main exhaust pipe with low moisture content, it is opened to the resonance chamber of the third chamber 9, and a sound absorber consisting of a sound absorbing material 10 and a communicating small hole 12 is installed in the middle of the inner pipe 3a. 11 is provided around the inner tube 3a, the inner tube 3a is opened to the second expansion chamber 13 through a small hole 14, and a connecting tube 15 is provided on the partition plate between the first and second chambers 7 and 13.

FIG. 2 shows an embodiment in which only the inner tube 3a is introduced into the muffler 2. In this case, the sound absorber 11 and other appropriate muffling means can be immediately assembled to the inner tube 3a within the muffler. Then, the space 4 within the outer pipe 3b is sealed in front of the muffler, and the water is discharged from the drain pipe 20 together with the mixed exhaust gas. Note that the water drainer is omitted in the diagram.

FIG. 3 shows another example of the draining mechanism, in which a torsion plate 17 is provided in the inner tube 3a, and a large number of small holes 18 are provided in the inner tube wall around the torsion plate 17.

FIG. 4 shows an embodiment in which the drainer is constructed of a perforated cone 19.

In Figure 5, the outer tube 3b is eccentrically placed over the inner tube 3a, the large space between both tubes is directed downward, and the inner tube 3a is placed over the inner tube 3a.
This is an example in which a hole 6 is provided on the lower side.

Note that the water draining and discharging mechanism described above is provided at one or more locations before and after the inner pipe.

C. Effects of the invention In equipment that mixes water with exhaust gas, such as the exhaust system of outboard motors, up to the silencer,
By discharging the mixed water together with the exhaust gas into the space inside the outer pipe, and by making the downstream part of the exhaust pipe into a main exhaust conduit that contains almost no water, the water mixing type exhaust pipe can be mixed with other noise reduction elements. Combinatorial bonds can be made without considering water.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of the exhaust system of the present invention, FIGS. 2 to 4 are longitudinal cross-sectional views of main parts of other embodiments, and FIG. 5 is a cross-sectional view of an eccentric double pipe. 1 is an internal combustion engine, 2 is a muffler, 3 is a hollow double pipe consisting of an inner pipe 3a and an outer pipe 3b, 5 is a pipe for introducing water into the inner pipe 3a, 6 and 18 are openings provided in the inner pipe 3a,
17 and 18 are drained.

Claims (1)

[Scope of utility model registration request] In an exhaust system that mixes water with exhaust gas, the exhaust pipe has a hollow double structure, and the inner pipe communicates with the exhaust port of the internal combustion engine, and a water inlet is provided near the exhaust port to mix water with the exhaust gas. A drain and a small opening are provided in the inner pipe to allow water to be discharged into the space between the inner and outer pipes together with the exhaust gas using the exhaust discharge pressure before reaching the muffler. An exhaust system for an internal combustion engine in which a water pipe and an inner pipe are used as the main exhaust pipe, and the main exhaust pipe can be connected to other silencing elements.