JPH0939892A - Water jet propulsion machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the muffling effect by supplying water having the capacity sufficient to damp sound energy of an exhaust gas in an internal combustion engine from a volute casing, and providing a muffling chamber for discharging exhaust gas into the water. SOLUTION: In a water jet propulsion machine, high-pressure water is injected from a volute casing 2 into a muffling chamber 3, and the water is mixed to exhaust gas E of an engine and discharged from an exhaust outlet 4 to the atmosphere. In the low-speed rotation, exhaust gas is introduced from a hole 22 into an underwater exhaust pipe 34 against atmospheric pressure, muffled through first and second expansion chambers 31, 32, and then discharged to the atmosphere. On the other hand, in the cruising speed state, the pressure of exhaust gas, the capacity and the pressure of high-pressure water to be injected from the hole 22 into the underwater exhaust chamber 34 are increased, pressure of the exhaust gas is predominant a little, and the exhaust gas is discharged. However, since water whose pressure is increased is raised also in the underwater exhaust chamber 34, sound energy of the exhaust gas is absorbed and muffled by water and then discharged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water jet type propulsion device, and more particularly to a water jet type propulsion device having a sound deadening chamber.

[0002]

2. Description of the Related Art The exhaust gas of an internal combustion engine is at a high pressure and a high temperature. If the exhaust gas is directly discharged into the atmosphere, the gas expands rapidly and generates explosion sound. Exhaust gas was exhausted into seawater outside the ship and silenced was a common method of silencing. The silencing method using water is to attenuate the acoustic energy of the exhaust gas due to the viscosity of the water.For example, in a screw type outboard motor, the exhaust gas flow path is extended below the water surface to exhaust the exhaust gas from around the propeller shaft. It was released into water and had a sound-deadening effect. A water jet type propulsion device having a sound deadening structure shown in FIG. 12 is known. The muffling structure guides an exhaust pipe communicating with an exhaust port of the engine to the discharge port 20, thereby confining the exhaust E in a column C formed by a jet jet, absorbing the energy of the exhaust sound in the jet, and silencing the exhaust. Occasionally, the reverse gate 40 is raised to change the direction of the jet jet to the direction opposite to the traveling direction of the ship, and exhaust gas is released backward from the notch 41 of the reverse gate 40. Such a notch 41 is provided to avoid the fact that, when the jet with the exhaust gas mixed therein is sucked into the suction port, the thrust is remarkably reduced and vibration may be generated, which may have a serious effect on the engine. Things.

[0003]

However, the greatest advantage of the water jet type propulsion system is that it does not have a propeller projecting below the bottom of the ship, and it is impossible to exhaust deeply below the water surface in the first place. , The silencing structure,
There were the following problems. First, while traveling at the cruising speed, in the silencing structure shown in FIG. 12, the exhaust E trapped in the cylinder C formed by the jet was separated upward by the buoyancy and was discharged to the atmosphere. Good silencing effect was not obtained. In addition, the water jet thruster pumps the surrounding water with a pump and obtains thrust by the reaction force of the jet jetting backward,
The suction port 24 is provided at a shallow position below the water surface, and if the underwater exhaust is to be performed as in the case of the conventional outboard motor, the pump itself may inhale the exhaust from the suction port 24. Therefore, in a water jet type propulsion machine,
Silencing by underwater exhaustion was difficult in practice. Further, when the reverse gate 40 is raised at the time of retreat and the direction of the jet jet is changed to the direction opposite to the traveling direction of the ship, the exhaust is discharged into the atmosphere from the notch 41 of the reverse gate 40, so that the sound deadening effect is completely eliminated. Had been lost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a water jet propulsion device having a large noise reduction effect. Third, to provide a water jet propulsion device that does not inhale exhaust gas from the suction port, and thirdly, to provide a water jet propulsion device that is vertically compact and can reduce manufacturing costs by providing a silencing chamber inside. It is to be.

[0005]

In order to achieve the above object, the invention described in claim 1 is such that a sufficient amount of water for attenuating the acoustic energy of exhaust gas of an internal combustion engine is directly supplied from a volute casing. In addition, it is a water jet propulsion machine equipped with a muffling chamber that exhausts exhaust gas into the water. Here, since the amount of water is sufficient to attenuate the acoustic energy of the exhaust gas, the muffling chamber is allowed to accommodate the amount of water that can increase the mixing ratio with the exhaust gas. Further, the fact that such water is directly supplied from the volute casing means that there is nothing interposed between the volute casing and the silencing chamber.For example, the water supplied from the volute casing is used as engine cooling water. That is, it is not supplied to the muffling room after it has been released. Thus, according to the invention described in claim 1, since a sufficient amount of water for damping the acoustic energy of the exhaust gas is directly supplied from the volute casing to the muffling chamber, a water jet propulsion device having a large muffling effect is provided. Can be provided.

According to a second aspect of the present invention, in the first aspect of the invention, the muffling chamber is arranged at a position higher than the water surface when the boat equipped with the water jet propulsion device is running. It is what According to this invention, since the exhaust outlet of the exhaust gas provided in the muffling chamber can be provided above the water surface, it is possible to provide the water jet propulsion device in which the suction port of the pump does not suck the exhaust gas.

According to a third aspect of the invention, in the second aspect of the invention, the silencing chamber is arranged between the internal combustion engine and the volute casing. According to this invention, the water jet propulsion device can have a muffling chamber therein, is vertically compact, and
It is possible to provide a water jet propulsion device that can reduce manufacturing costs.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the muffling chamber is an expansion chamber connected to an exhaust port of an internal combustion engine, and an underwater exhaust chamber to which water is supplied from a volute casing. An exhaust passage for guiding the exhaust gas from the expansion chamber to the underwater exhaust chamber, and an exhaust outlet for exhausting the exhaust gas whose acoustic energy is attenuated by the water filled in the underwater exhaust chamber. According to this invention, the high-temperature and high-pressure exhaust gas is decompressed in the expansion chamber, reaches the underwater exhaust chamber through the exhaust passage, the energy is absorbed by the water, and the sound is silenced. Exhausted to. Therefore, it is possible to provide a water jet propulsion machine having a great sound deadening effect as if exhausted deep below the water surface.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the muffling chamber includes a second expansion chamber that is connected to the expansion chamber, and the exhaust gas is discharged when the internal combustion engine rotates at a low speed. It is characterized in that it is released into the atmosphere from the second expansion chamber. This invention considers the exhaust at the time of idling or the low speed rotation when the pressure of the exhaust gas is weaker than that at the time of high engine rotation, and the pressure of such exhaust gas is weaker than the pressure of the water in the underwater exhaust chamber, The exhaust gas can be discharged into the atmosphere via the second expansion chamber without passing through the underwater exhaust chamber. Therefore, the stable rotation of the engine can be maintained even when the engine rotates at a low speed.

The invention according to claim 6 is characterized in that, in the invention according to claim 5, the underwater exhaust chamber is provided so as to surround an exhaust passage. In such an invention, high-temperature and high-pressure exhaust gas can be water-cooled,
The exhaust volume can be reduced and the exhaust efficiency can be increased, and at the same time, the sound energy can be absorbed as heat and the sound deadening effect can be obtained.

According to the invention described in claim 7, in claim 4,
The invention according to 5 or 6 is characterized in that the underwater exhaust chamber and the volute casing are communicated with each other by a hole provided in the upper wall of the volute chamber of the volute casing near the discharge port. According to this invention, the high-pressure water in the volute chamber of the volute casing near the discharge port is always
It will be supplied to the underwater exhaust chamber. Therefore, even if the water in the underwater exhaust chamber is discharged together with the exhaust gas from the exhaust outlet, the amount of water does not become insufficient, and a constant silencing effect can be always obtained. Also, at the time of high engine speed,
Even if a large amount of water in the underwater exhaust chamber is discharged from the exhaust outlet due to an increase in the amount of exhaust gas and the exhaust pressure, the pressure inside the volute casing further increases as the rotation increases, and a larger amount of water enters the underwater exhaust chamber. Since the amount of inflow and the amount of discharge can be supplemented, a constant silencing effect can be always obtained.

The invention described in claim 8 is characterized in that, in each of the above inventions, the width of the internal combustion engine along the lateral direction of the boat is wider than the width along the longitudinal direction of the boat. In this invention, the internal combustion engine of the water jet propulsion device is placed horizontally, and the same center of gravity as that of the conventional vertically long propulsion device can be obtained without disposing the propulsion device on the transom plate.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a water jet propulsion device according to the present invention will be described below with reference to FIGS. FIG. 1 is a plan view of a boat equipped with a water jet propulsion device according to the present invention, FIG. 2 is a left side view of the water jet propulsion device showing a mounted state with respect to the boat, FIG. 3 is a rear view of the water jet propulsion device, FIG. 4 is a sectional view of the AA line shown in FIG. 2 excluding the internal combustion engine. Also,
5 to 8 are a plan view, a bottom view, a rear view, and a left side view of the sound deadening block constituting the sound deadening chamber.

Water jet propulsion machine J according to the present invention
As shown in FIGS. 2 and 3, is provided with a silencing block 3A that constitutes a silencing chamber 3 between the engine 1 and the volute casing 2. As shown in FIG. 4, the silencing chamber 3 has a volute casing. The high-pressure water W is injected from 2 and the water is mixed with the exhaust gas E of the engine 1 to absorb the acoustic energy of the exhaust gas E, mute the sound, and discharge it from the exhaust outlet 4 into the atmosphere. There is. According to such a sound deadening mechanism, since high pressure water is used as a medium for absorbing the acoustic energy of the exhaust gas, a large amount of water can be constantly supplied to the sound deadening chamber during traveling, and The mixing ratio of water can be increased, and a sound deadening effect can be exhibited. Further, it is possible to provide the water jet propulsion device J in which the muffling chamber 3 can be provided in the water jet propulsion device J, which is compact in the vertical direction and which can reduce the manufacturing cost.

As shown in FIG. 4, the muffler chamber 3 has a primary expansion chamber 31 connected to an exhaust port 30 of the engine 1.
And a second expansion chamber 32 connected to the first expansion chamber 31.
An exhaust passage 33 for guiding exhaust gas downward from the primary expansion chamber 31, and a submerged exhaust chamber 34 in which the exhaust gas from the exhaust passage 33 and water supplied from the volute casing 2 are mixed. .

The primary expansion chamber 31 is for avoiding the rapid expansion of the exhaust gas, and the exhaust gas flowing into this is
When the engine 1 is idling or running at a low speed, the second
It escapes into the next expansion chamber 32 and is released into the atmosphere. And
As the rotation of the engine 1 increases, the pressure of the exhaust gas increases and flows down the exhaust passage 33. The primary expansion chamber 31 rises in the exhaust passage 33 as the volume of the exhaust gas is reduced by being cooled by the water column of the underwater exhaust chamber 34 surrounding the exhaust passage 33 when the engine 1 is stopped. It also serves as an escape space to prevent the coming water column from entering the exhaust port.

The exhaust passage 33 guides the exhaust gas from the primary expansion chamber 31 to the underwater exhaust chamber 34, and the underwater exhaust chamber 3 is introduced from an inlet 32a provided at the bottom of the primary expansion chamber 31.
As it descends in 4, it is gradually tapered,
It is formed in a hollow shape. As shown in FIG. 4, the thus formed exhaust passage 33 is surrounded by water filled in a submerged exhaust chamber 34, and the exhaust passage 33 is water-cooled by a water column of the water, and exhausted. It cools the gas and silences it. Although the cross-sectional shapes of the primary expansion chamber 31 and the exhaust flow path 33 connected to the primary expansion chamber 31 are substantially rain-dew-shaped,
Alternatively, the primary expansion chamber 31 and the exhaust passage 33 may be continuously formed into a tapered shape.

Water is supplied to the underwater exhaust chamber 34 from a hole 22 provided in an upper wall of the volute chamber 21 of the volute casing 2 near the discharge port 20, and the exhaust passage 3 is introduced into the water.
3 to exhaust the exhaust gas. The volute casing 2 is fixed to the drive shaft 61 of the engine 1, sucks water from the suction port 24 by the rotating impeller 23, pressurizes it, and ejects high-pressure water from the discharge port 20. It is shaped like a vortex with the cross-sectional area of the channel expanded to convert the velocity energy of water at the impeller outlet into pressure energy. Therefore, the volute casing 2 close to the discharge port 20
From the hole 22 provided in the upper wall of the spiral chamber 21, high-pressure water whose pressure increases substantially in proportion to the rotation speed of the impeller 23 is always injected into the underwater exhaust chamber 34. The amount of water is sufficient to absorb the acoustic energy of the exhaust gas. The hole 22 may be provided in at least one place, and may be inclined so as to be along the flow path of water in the volute casing 2. An exhaust outlet 4 for exhausting exhaust gas is provided above the underwater exhaust chamber 34. The exhaust outlet 4
Is located on the water surface as shown in FIG. 4, so that the pump does not suck the exhaust gas from its suction port 24.

In order to prevent the water in the underwater exhaust chamber 34 from rocking, a buffer material may be housed in the underwater exhaust chamber 34. In FIG. 4, 5 is a bearing case, 6 is a bolt / nut, and 60 is a driving shaft chamber.

The sound deadening block 3A and the volute casing 2 of the water jet propulsion machine configured as described above.
Are made of an aluminum alloy casting, respectively, are bolted through packings, and are assembled together with the engine 1. Then, as shown in FIG. 1 and the like, the width of the internal combustion engine along the left-right direction of the boat B is wider than the width along the front-rear direction of the boat B, and is mounted horizontally via the clamp 50. In a conventional outboard motor, the engine is placed vertically long and the front half of the engine is mounted on a transom plate in order to make the center of gravity as close to the front as possible. As in the present invention, when placed horizontally, the same center of gravity as the conventional vertically long propulsion unit can be obtained without disposing the propulsion unit on the transom plate, and the propulsion unit is low in length and compact. .

Next, the operation of the water jet propulsion device according to the present invention will be described with reference to FIGS. 9 to 11.

FIG. 9 schematically shows a state before the engine 1 is started, and FIG. 10 schematically shows a state at idling or low speed rotation, which is a state in which there is no load and the rotation speed is the lowest. ing. In this state, the exhaust gas is introduced into the underwater exhaust chamber 34 from the hole 22 against the atmospheric pressure, while the exhaust gas pressure is also weak, so the exhaust gas reaches the second expansion chamber 32 through the primary expansion chamber 31. , Silenced and released into the atmosphere.

FIG. 11 schematically shows the state in which the engine 1 is gradually increased in speed, so to speak, at a cruising speed. As the engine 1 speed increases, the exhaust gas pressure increases. To do. On the other hand, as the rotational speed of the impeller 23 increases, high-pressure water also flows from the hole 22 into the underwater exhaust chamber 3.
The amount injected into 4 increases and its pressure also increases.
In the vicinity of the outlet 33b of the exhaust passage 33, the pressure of the exhaust gas becomes slightly dominant, and the exhaust gas is discharged. Accordingly, the water in the underwater exhaust chamber 34 does not enter the exhaust passage 33 and the pressure inside the volute casing 2 is high, so that the exhaust gas does not enter the spiral chamber 21 through the hole 22. On the other hand, in the underwater exhaust chamber 34 surrounding the exhaust passage 33, the water rises against the atmospheric pressure and rises almost to the vicinity of the exhaust port. Then, the exhaust sound is generated by the underwater exhaust chamber 34.
The acoustic energy is absorbed by the water filled with the water and is silenced, and is cooled by the water. Although water may be discharged from the exhaust outlet 4 together with the exhaust gas, since the high-pressure water is continuously supplied from the volute casing 2, the silencing effect is kept constant.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The inventor prototyped a water jet propulsion machine having a silencing chamber 3 having the following configuration. The height of the exhaust passage 33 is about 10 cm, the sectional area of the exhaust passage inlet 33a is about 10 cm ² , the sectional area of the exhaust passage outlet 33b is about 5 cm ² , and the position of the hole 22. Is the exit 33
Approximately 2 cm from the position horizontally displaced from the end of b by approximately 1 cm.
It was located just under 5 cm, and its prototype was about 6 mm in diameter. The allowable volume of water in the underwater exhaust chamber 34 is about 1.5
I made a prototype. The engine 1 is a water-cooled engine (10
ps / 5,500 rpm). As a result, when the occupant had a conversation at a distance of 1 m while traveling at the cruising speed, a noise reduction effect was obtained to such an extent that a comfortable conversation was possible.

[0025]

According to the invention described in claim 1, since a sufficient amount of water for damping the acoustic energy of the exhaust gas is directly supplied from the volute casing to the silencing chamber, the water jet propulsion having a large silencing effect. Machine can be provided.

According to the second aspect of the present invention, since the exhaust port for the exhaust gas provided in the muffling chamber can be provided above the water surface, a water jet propulsion device that does not suck the exhaust gas from the suction port of the pump can be provided. Can be provided.

According to the third aspect of the present invention, the water jet propulsion device can have a muffling chamber therein.
It is possible to provide a water jet propulsion device that is vertically compact and that can reduce manufacturing costs.

According to the invention described in claim 4,
The high-pressure exhaust gas is decompressed in the expansion chamber, reaches the underwater exhaust chamber through the exhaust flow path, the water absorbs energy, is silenced, and is exhausted to the atmosphere from the exhaust outlet.
Therefore, it is possible to provide a water jet propulsion machine having a large noise reduction effect.

In the invention described in claim 5, the exhaust gas pressure is considered to be weak when the engine is idling or the engine speed is low compared to when the engine is rotating at high speed. When the pressure is lower than the pressure of water, the exhaust gas does not pass through the underwater exhaust chamber but is exhausted into the atmosphere through the second expansion chamber.

According to the sixth aspect of the invention, the high-temperature and high-pressure exhaust gas can be water-cooled, and a sound deadening effect can be obtained from this aspect.

In the invention described in claim 7, the high-pressure water in the volute chamber of the volute casing near the discharge port is always
It will be supplied to the underwater exhaust chamber. Therefore, even if the water in the underwater exhaust chamber is discharged together with the exhaust gas from the exhaust outlet, the amount of water does not become insufficient, and a constant silencing effect can always be obtained. Also, when the engine speed is high, the amount of exhaust gas increases and the exhaust pressure also increases, so even if a large amount of water in the underwater exhaust chamber is discharged from the exhaust outlet, the pressure in the volute casing will increase further, and a larger amount of water will be released underwater. Since it can flow into the exhaust chamber and compensate for the amount of discharge, a constant silencing effect can be obtained at all times.

According to the eighth aspect of the present invention, the internal combustion engine of the water jet propulsion device is placed horizontally, and the same center of gravity position as that of the conventional longitudinally long propulsion device can be obtained without disposing the propulsion device on the transom plate. To be

[Brief description of drawings]

FIG. 1 is a plan view of a boat equipped with a water jet propulsion device according to the present invention,

FIG. 2 is a left side view of the water jet propulsion device, showing a state of attachment to a boat;

FIG. 3 is a rear view of the water jet propulsion device,

FIG. 4 is a sectional view of the AA line shown in FIG. 2 excluding the internal combustion engine;

FIG. 5 is a plan view of a muffling room block,

FIG. 6 is a bottom view of the muffler block,

FIG. 7 is a rear view of the muffling room block,

FIG. 8 is a left side view of the sound deadening room block,

FIG. 9 is an explanatory view of the operation of the water jet propulsion device according to the present invention,

FIG. 10 is an operation explanatory view of a water jet propulsion device according to the present invention,

FIG. 11 is an operation explanatory view of a water jet propulsion device according to the present invention,

FIG. 12 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 1 Engine 2 Volute Casing 3 Noise Suppression Chamber 3A Noise Suppression Block 4 Exhaust Outlet 5 Bearing Case 6 Bolt Nut 20 Discharge Port 21 Whirlpool Chamber 22 Hole 23 Impeller 24 Suction Port 30 Exhaust Port 31 Primary Expansion Chamber 32 Secondary Expansion Chamber 33 Exhaust Channel 34 Underwater Exhaust Chamber 33a Inlet 33b Outlet 40 Reverse Gate 41 Notch 50 Clamp 60 Drive Shaft Chamber 61 Drive Shaft

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Soichi Ide 2nd floor, 2-1-24 Yaguchi, Ota-ku, Tokyo 1st floor, Aizawa Building KB Food Co., Ltd. Tokyo Sales Office

Claims (8)

[Claims] 1. A water jet propulsion device provided with a sound absorbing chamber for exhausting the exhaust gas into the water, while a sufficient amount of water for damping the acoustic energy of the exhaust gas of the internal combustion engine is directly supplied from the volute casing. 2. The water jet propulsion device according to claim 1, wherein the silencing chamber is arranged at a position higher than a water surface when a boat equipped with the water jet propulsion device is traveling. 3. The water jet propulsion device according to claim 2, wherein the silencing chamber is arranged between the internal combustion engine and the volute casing. 4. The muffler chamber includes an expansion chamber connected to an exhaust port of an internal combustion engine, an underwater exhaust chamber to which water is supplied from a volute casing, and an exhaust gas for guiding exhaust gas from the expansion chamber to the underwater exhaust chamber. The water jet propulsion device according to claim 3, comprising a flow path and an exhaust outlet for exhausting exhaust gas whose acoustic energy is attenuated by water filled in the underwater exhaust chamber. 5. The muffler chamber includes a second expansion chamber connected to the expansion chamber, and discharges exhaust gas from the second expansion chamber to the atmosphere when the internal combustion engine rotates at a low speed. Item 4. The water jet propulsion device according to Item 4. 6. The water jet propulsion device according to claim 4, wherein the underwater exhaust chamber is provided so as to surround an exhaust passage. 7. The underwater exhaust chamber and the volute casing are communicated with each other by a hole provided in the upper wall of the volute chamber of the volute casing near the discharge port. Water jet propulsion machine described. 8. The water jet propulsion device according to claim 1, wherein the internal combustion engine has a width along the left-right direction of the boat that is wider than a width along the front-rear direction of the boat.