JP2816658B2 - Water jet thruster - Google Patents

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 provides an internal combustion engine and a volute.
Water surface when the boat is running, located between the casings
With a silencer chamber located higher than
In the jet propulsion device, the muffling chamber is an internal combustion engine
The primary expansion chamber connected to the exhaust port of
In the upper wall of the spiral chamber of the volute casing
Through the volute casing
Exhaust chamber, to which water is supplied, and exhaust gas
An exhaust passage leading from the expansion chamber to the underwater exhaust chamber;
Water provided in the upper part of the exhaust chamber and filled with the underwater exhaust chamber
Exhaust gas whose acoustic energy has been attenuated by
Exhaust outlet, and the silencing chamber is
A secondary expansion chamber connected to the primary expansion chamber;
Exhaust gas is released from the secondary expansion chamber to the atmosphere during low-speed rotation
It is characterized by doing .

[0006] According to the invention described in claim 1 Thus, muffling chamber distribution on the surface of the water by remote high position during travel of the boat
And the exhaust outlet of the exhaust gas
Since it is provided above the submersible exhaust chamber that constitutes
The outlet will be located above the water surface and the pump suction
The water jet that the inlet does not suck the exhaust
Motivation can be provided .

[0007] The silencing chamber is provided with an internal combustion engine and a volute case.
Water jet
A muffler room can be built inside the machine, and the vertical
Compact and cost effective
-A jet jet propulsion device can be provided.

The silencing chamber is connected to an exhaust port of an internal combustion engine.
The primary expansion chamber that is in contact and the volute case near the discharge port
Communicated by a hole in the upper wall of the vortex chamber
And water is supplied from the volute casing
A submerged exhaust chamber, and exhausting the exhaust gas from the expansion chamber to the submerged exhaust.
An exhaust passage leading to the chamber, and an upper part of the underwater exhaust chamber.
And the water supplied to the underwater exhaust chamber
And the exhaust outlet for exhausting the exhaust gas
You. Therefore, high-temperature and high-pressure exhaust gas passes through the first expansion chamber.
It is depressurized, reaches the underwater exhaust chamber via the exhaust flow path, and
Water absorbs energy, silences, and exhausts underwater
It is exhausted into the atmosphere from the exhaust outlet at the top of the room,
As well as deep exhaust under the water,
-A jet jet propulsion device can be provided. Only
Also, the height inside the volute chamber of the volute casing near the discharge port
Since the pressurized water will always be supplied to the underwater exhaust chamber,
The water in the underwater exhaust chamber together with the exhaust gas from the exhaust outlet
Even if water is released, the amount of water does not run out
A silencing effect can be obtained. Also, high engine speed
Occasionally, the exhaust gas volume increases, the exhaust pressure also increases, and
Even if a large amount of water in the air chamber is released from the exhaust
The pressure inside the heat casing increases as the rotation increases.
More water flows into the submersible exhaust chamber and discharges
You can make up for the minute, so you always get a certain amount of silencing effect
be able to. Further, the muffling chamber is provided with the primary expansion.
A low-speed rotation of the internal combustion engine is provided with a secondary expansion chamber connected to the chamber.
At times, the exhaust gas is released from the secondary expansion chamber to the atmosphere. You
That is, the exhaust gas pressure is higher than when the engine is running at high speed.
Considering exhaust during low idling and low speed rotation
The pressure of the exhaust gas is the pressure of the water in the underwater exhaust chamber.
Exhaust gas does not pass through the underwater exhaust chamber,
Exhaust into the atmosphere via the secondary expansion chamber
Things. Therefore, even at low engine speeds,
The stable rotation of the gin can be maintained.

According to a second aspect of the present invention, in the first aspect, 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. Further, in the invention described in claim 1, the exhaust gas
The flow path is formed through an inlet provided at the bottom of the primary expansion chamber.
As it descends in the underwater exhaust chamber, it gradually tapers.
And formed into a hollow shape, and the first expansion chamber
The cross-sectional shape of the exhaust flow path that follows this is formed almost like a rain-dew type
(The invention according to claim 4).

According to a third aspect of the present invention, in each of the above aspects, the width of the internal combustion engine along the left-right direction of the boat is wider than the width along the front-rear 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.

[0011]

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 device J according to the present invention
Is provided with a muffling block 3A which constitutes a muffling chamber 3 between the engine 1 and the volute casing 2 as shown in FIGS. 2 and 3, and as shown in FIG. High-pressure water W is injected from hole 2 through hole 22 , the water is mixed with exhaust gas E of engine 1, the acoustic energy of exhaust gas E is absorbed, silenced and exhausted from exhaust outlet 4 to the atmosphere. It is supposed to. According to such a silencing 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 silencing chamber during traveling, and The mixing ratio of water can be increased, and a sound deadening effect can be exhibited. Further, the sound deadening chamber 3 can be provided inside the water jet propulsion device J, and the water jet propulsion device can be provided that is compact in the vertical direction and that can reduce the manufacturing cost.

As shown in FIG. 4, the muffler chamber 3 includes 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 preventing a rapid expansion of the exhaust gas.
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. When the engine 1 is stopped, the primary expansion chamber 31 is cooled by the water column of the underwater exhaust chamber 34 surrounding the exhaust flow path 33 and the volume of the exhaust gas is reduced. It also serves as an escape space to prevent the incoming water column from entering the exhaust port.

[0015] The exhaust flow path 33, exhaust gas and guides the primary expansion chamber 31 into the water discharge chamber 34, the inlet 3 3 a underwater exhaust chamber 3 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.

The underwater exhaust chamber 34 is supplied with water from a hole 22 provided in the upper wall of the volute chamber 21 of the volute casing 2 close to the discharge port 20, and the exhaust passage 3
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 the water, and jets high-pressure water from the discharge port 20. The flow path is formed into a vortex shape with an enlarged cross-sectional area of the flow path, and converts 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.

Incidentally, in order to prevent the water from oscillating in the underwater exhaust chamber 34, a buffer material may be accommodated in the underwater exhaust chamber 34. 4, 5 indicates a bearing case, 6 indicates a bolt and a nut, and 60 indicates a drive shaft chamber.

The silencing block 3A and the volute casing 2 of the water jet propulsion device 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.

FIG. 9 schematically shows a state before the engine 1 is started, and FIG. 10 schematically shows a state at the time of idling or low-speed rotation where no load is applied and the rotation speed is the lowest. ing. In this state, water is introduced into the underwater exhaust chamber 34 from the hole 22 against the atmospheric pressure, while the exhaust gas pressure is also weak. 2 It reaches the expansion chamber 32, where the sound is muted and released to the atmosphere.

FIG. 11 schematically shows a state in which the rotation speed of the engine 1 is gradually increased, so to speak, at a cruising speed. As the rotation speed of the engine 1 increases, the pressure of the exhaust gas increases. I 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. Thus, the exhaust sound is generated in 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 together with the exhaust gas from the exhaust outlet 4, since the high-pressure water is continuously supplied from the volute casing 2, the noise reduction effect is kept constant.

[0022]

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 exit 33
1. About 1 cm from the position shifted horizontally about 1 cm from the end of b.
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.

[0023]

According to the first aspect of the present invention, the sound deadening room is provided.
The exhaust port for exhaust gas provided on the
It is possible to suck exhaust gas from the suction port of the pump
Can provide water jet propulsion machine
You.

The water jet propulsion unit has a sound deadening chamber.
Can be embedded, vertically compact, or
In addition, water jets can reduce manufacturing costs.
A thruster can be provided.

Also, high temperature and high pressure exhaust gas is supplied to the expansion chamber.
It is depressurized, reaches the underwater exhaust chamber via the exhaust flow path, and
Energy absorbed by water, silenced, exhaust outlet
It is more exhausted to the atmosphere. Therefore, the noise reduction effect
Water jet propulsion can be provided.

Also, compared to when the engine is running at a high speed, the exhaust gas
Exhaust gas during idling or low-speed rotation with low pressure
Pressure is lower than the pressure of water in the underwater exhaust chamber.
Means that the exhaust gas does not pass through the submerged exhaust chamber,
And can be exhausted to the atmosphere via

Furthermore, a volute casing close to the discharge port
High-pressure water in the vortex chamber is always supplied to the submersible exhaust chamber
In addition to the exhaust gas from the exhaust outlet,
Even if the water in the exhaust chamber is released, there is no shortage of water,
A constant silencing effect can always be obtained. Also, engine
When the engine rotates at high speed, the exhaust gas volume increases and the exhaust pressure also increases.
And a large amount of water in the underwater exhaust chamber is released from the exhaust outlet.
The pressure inside the volute casing is even higher,
A large amount of water flows into the underwater exhaust chamber, making up for
As a result, a constant silencing effect can always be obtained.

According to the second aspect of the present invention, the high-temperature and high-pressure exhaust gas can be water-cooled, and a noise reduction effect can be obtained from that aspect.

According to the third aspect of the invention, the internal combustion engine of the water jet propulsion device is placed horizontally, and the same center of gravity as the conventional vertically long propulsion device can be obtained without disposing the propulsion device on the transom plate. Can be

[Brief description of the 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]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Volute casing 3 Silence room 4 Exhaust outlet 5 Bearing case 6 Bolt and nut 20 Discharge port 21 Vortex chamber 22 Hole 23 Impeller 24 Suction port 30 Exhaust port 31 First expansion chamber 32 Second expansion chamber 33 Exhaust flow Road 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 2-1-24 Yaguchi, Ota-ku, Tokyo The first floor of the 1st Aizawa Building The Tokyo sales office of KB Foods Co., Ltd. (56) References JP-A-2-175494 (JP, A JP-A-1-273788 (JP, A) JP-A-60-25889 (JP, A) JP-A-1-237291 (JP, A) JP-A-8-253196 (JP, A) JP-A-63-1988 215495 (JP, A) Japanese Utility Model Hei 2-75398 (JP, U) Japanese Utility Model Utility Model No. 2-12998 (JP, U) Registered utility model 3001944 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , (DB name) B63H 20/00 B63H 20/24 B63H 21/32 B63H 11/00

Claims (4)

(57) [Claims] 1. Between an internal combustion engine and a volute casing
It is located at a position higher than the water surface when the boat is running
Water jet propulsion with silencer located
The muffler chamber is connected to a first exhaust port of an internal combustion engine.
Installed on the upper wall of the secondary expansion chamber and the volute chamber of the volute casing near the discharge port.
Are connected to each other by the
An underwater exhaust chamber to which water is supplied from a sink, and an exhaust gas from the first expansion chamber to the underwater exhaust chamber.
An exhaust passage , provided above the underwater exhaust chamber, and filled with the underwater exhaust chamber.
Exhaust gas whose acoustic energy has been attenuated by trapped water
An exhaust outlet for exhausting air, and the muffling chamber is connected to the primary expansion chamber for secondary expansion.
Exhaust gas during the low-speed rotation of the internal combustion engine.
A water jet propulsion device that discharges water from the expansion chamber to the atmosphere . 2. The water jet propulsion device according to claim 1 , wherein the underwater exhaust chamber is provided so as to surround an exhaust passage. Wherein the internal combustion engine is a water jet propulsion unit according to claim 1 or 2, characterized in that the direction of width along the lateral direction of the boat is wider than the width along the longitudinal direction of the boat. 4. The exhaust passage is provided at a bottom of the primary expansion chamber.
As it descends through the underwater exhaust chamber from the entrance provided in the
And gradually tapered to form a hollow shape.
And a cross section of the primary expansion chamber and an exhaust passage directly connected to the primary expansion chamber.
The shape is substantially rain-dew type
Item 7. A water jet propulsion device according to item 1.