JPH0761396A - Exhausting device for small boat - Google Patents

Abstract

PURPOSE:To prevent entrance of water to an engine by preventing the reverse flow of water through a muffler to the engine side even when a boat is capsized. CONSTITUTION:A muffler 25 having one end coupled to the exhaust port 22 side of an engine 6 and the other end extended to a position in a level lower than that of an exhaust port 22. A water lock device 28 is arranged to the extension end 26 side of the muffler 25. A reverse flow preventing device 35 to prevent the reverse flow of water 50 from the water lock device 28 side to the muffler 25 side is located between the water lock device 28 and the muffler 25. The reverse flow preventing device 35 and the waterlock device 28 are juxtaposed approximately in a horizontal direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust system for a small boat which prevents water outside the engine from entering the engine.

[0002]

2. Description of the Related Art A small boat is conventionally disclosed in Japanese Patent Laid-Open No. 1-2622.
There is one disclosed in Japanese Patent Publication No. 93.

According to this, a muffler having one end connected to the exhaust port side of the engine for driving the propulsion device and the other end extending to a position lower than the exhaust port is provided, and the extension end side of the muffler is provided. Is equipped with a water lock device.

When the engine is driven, its exhaust gas is sequentially discharged through the muffler and the water lock device to the outside of the boat.

Further, a butterfly type backflow prevention device for preventing water from flowing back into the engine through the exhaust port from the muffler side is provided between the upper end, which is one end of the muffler, and the exhaust port side. ing

[0006]

By the way, when the boat capsizes, the water lock device and the muffler are located above the backflow preventive device, so that the water accumulated in the water lock device is discharged from the muffler. It flows back to the side of the engine, drops directly onto the backflow prevention device, and accumulates there.

In this case, however, there is a problem that the backflow prevention device cannot sufficiently prevent water from entering the engine.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and prevents water from flowing back through the muffler to the engine side even when the boat capsizes, so that water can enter the engine. The purpose is not to.

[0009]

The features of the present invention for achieving the above object are as follows.

That is, a muffler 25 having one end connected to the exhaust port 22 side of the engine 6 and the other end extending to a position lower than the exhaust port 22 is provided, and a water lock is provided on the extension end 26 side of the muffler 25. A device 28 is provided. A backflow prevention device 35 for preventing backflow of water 50 from the water lock device 28 side toward the muffler 25 side.
Is provided between the water lock device 28 and the muffler 25. Same as above, the backflow prevention device 35 and the same as above water lock device 28 are arranged side by side in a substantially horizontal direction.

[0011]

[Operation] The operation of the above configuration is as follows.

As shown in FIG. 3, even when the boat 1 is overturned, since the backflow prevention device 35 is provided between the water lock device 28 and the muffler 25, the water is retained in the water lock device 28. Water 50 is the muffler 25
An attempt to backflow through the engine to the engine 6 side is prevented by the backflow prevention device 35.

Moreover, since the backflow prevention device 35 and the water lock device 28 are arranged side by side in a substantially horizontal direction, the water 5 accumulated on the water lock device 28 side is
The water pressure of 0 does not significantly act on the backflow prevention device 35, and thus the backflow is generated by the backflow prevention device 35.
Is more reliably prevented.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

In the figure, reference numeral 1 is a small boat propelled by water injection, which is floated on the water surface 2. In the figure, Fr indicates the front of the boat 1, and left and right described below means the direction toward the front.

The hull 3 of the boat 1 is made of resin.
An engine 6 and a fuel tank 7 are housed inside the bow 4 side, and a water injection unit 9 is housed inside the stern 8 side.

The water injection unit 9 has a water flow duct 11 extending forward and backward, and the front end of the water flow duct 11 is the hull 3
It is connected to the bottom of the ship and opens toward the water, and the rear end opens rearward from the rear surface of the stern 8.

The front end of the propulsion shaft 12 is connected to the output shaft of the engine 6, the rear end side of the propulsion shaft 12 is located in the middle of the water flow duct 11, and the propeller is located at the rear end of the propulsion shaft 12. 13 is attached.

At the rear end of the water flow duct 11, a nozzle 14 connected to the rear end is pivotally supported so as to be rotatable left and right.
On the other hand, on the upper surface of the bow 4 side, a steering shaft 16 is rotatably supported around its axis, and a bar type handle 17 is attached to the upper end of the steering shaft 16. The steering shaft 1
When the handle 14 is steered to the right (or left), the nozzle 14 is linked to 6 and the nozzle 14 is rotated to the right (or left).

A seat 18 is provided on the upper surface of the stern 8 side, and a rider 19 who straddles the seat 18 can grip the handle 17 and steer it.

By driving the engine 6, the propulsion shaft 12
When the propeller 13 is rotated through the water, the water 50 flows in the water flow duct 11, the water is jetted rearward through the nozzle 14, and the hull 3 moves forward by the reaction force of this jet. ing.

In the above case, the steering operation of the handle 17 allows the boat 1 to be steered by rotating the nozzle 14 left and right.

A pair of front and rear exhaust ports 22, 22 are formed on the upper left side surface of the cylinder 21 of the engine 6. Reference numeral 23 denotes an exhaust pipe, which has an inverted U-shape in a side view, and one end of which has a bifurcated shape to form the exhaust port 2
2, 22 are connected. Further, one end of a muffler 25 is connected to the extension end 24 at the other end of the exhaust pipe 23, and the extension end 26 side at the other end of the muffler 25 extends substantially horizontally toward the front. The muffler 25 is the exhaust pipe 2
3 is connected by an elastic bellows 27 made of rubber.

Reference numeral 28 is a water lock device, which has a box 29 fixed to the bottom of the ship,
An inlet pipe 30 is attached to the rear wall of the box body 29 at an intermediate portion in the vertical direction. Further, an outlet pipe 31 is provided on the upper surface plate of the box body 29, which penetrates the upper and lower portions of the box body 29 in the vertical direction.
The upper end of is connected to a discharge pipe 33 attached to the side wall of the hull 3 via an elastic tube 32 made of rubber.

A backflow prevention device 35 is provided between the extension end 26 of the muffler 25 and the inlet pipe 30 of the water lock device 28.
The extension end 26 of the muffler 25, the water lock device 28, and the backflow prevention device 35 are sequentially arranged side by side in a substantially horizontal direction.

The backflow prevention device 35 is formed by bending a single circular pipe, and is composed of an upstream pipe 36 and a downstream pipe 37 which are substantially U-shaped in an inverted shape in a side view. The rear end of the upstream pipe 36 is detachably connected to the extension end 26 of the muffler 25 by a bolt 38, and the front end of the upstream pipe 36 and the rear end of the downstream pipe 37 are integrally formed, The front end of the downstream pipe 37 is detachably connected to the inlet pipe 30 via a rubber elastic tube 40.

Inside the peripheral walls of the exhaust pipe 23, the muffler 25, and the backflow prevention device 35, the first water jacket 4 is provided.
2, second water jacket 43, and third water jacket 4
4 are formed, which are in communication with each other. FIG. 2
The inside of the water flow duct 11 on the downstream side of the propeller 13 shown by is connected to the upstream end of the first water jacket 42 by a first water pipe 45. Further, the downstream end of the third water jacket 44 is connected to the discharge pipe 33 by the second water pipe 46.
Are connected by. In addition, a small hole 47 is formed which connects the downstream end of the third water jacket 44 to the front end of the downstream pipe 37.

When the engine 6 is driven,
The exhaust 49 passes through the exhaust pipe 23, the muffler 25, the backflow prevention device 35, and the water lock device 28 in this order, and is discharged to the outside of the boat 1.

By driving the engine 6, the propeller 1
3, the water flow duct 1 on the downstream side of the propeller 13 rotates.
When the water pressure in 1 increases, the water 5 in this water flow duct 11
0 passes through the first water pipe 45 and the first water jacket 42
(Arrow A in FIG. 1). And this water 50
Is the first water jacket 42, the second water jacket 43,
And the exhaust 49 is cooled through the third water jacket 44 (arrow B in FIG. 1). After this, this water 50
The water is sent through the water pipe 46 into the discharge pipe 33, where the exhaust 49 is directly cooled, and the exhaust 49 is cooled.
At the same time, it is discharged out of the boat 1 (arrow C in FIG. 1).

A small amount of the water 50 reaching the third water jacket 44 is injected into the exhaust 49 at the end of the water lock device 28 on the side of the backflow prevention device 35 through the small hole 47 (FIG. 1 middle arrow D). Then, the water 50 is atomized and mixed with the exhaust 49 to directly cool the exhaust 49. Then, the water 50 passes through the water lock device 28 and the discharge pipe 33 together with the exhaust 49, and
It is discharged outside.

In the above case, the first to third water jackets 42
~ 44 and the water lock device 28 reduce the noise of the exhaust 49.

Further, as described above, the water 50 injected into the backflow prevention device 35 side end of the water lock device 28 through the small hole 47 is in the box 29 or in the front end side of the downstream side pipe 37 of the backflow prevention device 35. Although retained, the inner bottom surfaces 36a, 37a of the upstream side pipe 36 and the downstream side tube 37 of the backflow prevention device 35 project upward, so that these inner bottom surfaces 36a, 3a
7a prevents the accumulated water 50 from trying to flow back to the muffler 25 side.

As shown in FIGS. 1 and 2, the backflow prevention device 35 is provided between the water lock device 28 and the extension end 26 of the muffler 25 extending to a position lower than the exhaust port 22. Therefore, the position of the backflow prevention device 35 is lower than in the conventional case where the backflow prevention device 35 is provided between the exhaust port 22 side and the muffler 25. Therefore, the center of gravity of the boat 1 is lowered accordingly, and the steerability of the boat 1 is improved.

As shown in FIG. 3, the boat 1 capsized and the water 50 retained in the box 29 of the water lock device 28 and the front end side of the downstream pipe 37 of the backflow prevention device 35 was replaced by a muffler. The water 50 that tries to flow back to the 25 side and is injected into the downstream side pipe 37 from the small hole 47 is the muffler 2.
When trying to flow back to the 5 side, the water 50 is stored in the lower recess 37b of the downstream side pipe 37 which has been turned upside down, and the water 50 is prevented from flowing back to the muffler 25 side.

In the above case, the backflow prevention device 35 and the water lock device 28 are arranged side by side in a substantially horizontal direction. Therefore, the water pressure of the water 50 staying on the water lock device 28 side does not largely act on the backflow prevention device 35, and thus the backflow is more reliably prevented. When the water 50 overflows from the lower recess 37b of the downstream pipe 37, the overflowed water 50 is also stored in the lower recess 36b of the upstream pipe 36.

As shown in FIG. 4, when the capsized state is returned to the normal state shown in FIGS. 1 and 2, the water 50 accumulated in the lower recess 37b of the downstream pipe 37 at the capsized state is Inner bottom surfaces 36a, 37 of the upstream pipe 36 and the downstream pipe 37
It falls to the bottom of a (arrow E in FIG. 4). After this, the water 50 is sent to the water lock device 28 side by natural flow or the pressure of the exhaust 49.

In this manner, the water 50 flows back to the muffler 25 side or the muffler 25 flows back to the engine 6 side when the boat 1 is capsized or returned to the normal posture. Is prevented.

Although the above is based on the illustrated example, the first water pipe 4 is not provided with the first to third water jackets 42 to 44.
5 may be connected to the small hole 47.

[0039]

According to the present invention, a muffler having one end connected to the exhaust port side of the engine and the other end extending to a position lower than the exhaust port is provided, and a water lock is provided on the extending end side of the muffler. When the device is provided, a backflow prevention device for preventing water from flowing back from the water lock device side toward the muffler side is provided between the water lock device and the muffler.

Therefore, even when the boat capsizes, the water that has accumulated in the water lock device will be prevented from flowing back to the engine side through the muffler by the backflow preventing device.

Moreover, since the backflow prevention device and the water lock device are arranged side by side in a substantially horizontal direction, the water pressure of the water staying on the water lock device side exerts a large effect on the backflow prevention device. Therefore, the backflow is more reliably prevented by the backflow prevention device, and the water is prevented from actively flowing into the muffler.

Therefore, water is prevented from entering the engine, and the engine performance is kept good.

[Brief description of drawings]

FIG. 1 is a partially enlarged sectional view of FIG.

FIG. 2 is an overall side sectional view of the boat.

FIG. 3 is an operation explanatory view corresponding to FIG. 1 when the boat is capsized.

FIG. 4 is an operation explanatory view corresponding to FIG. 1 when the boat is returned to the normal posture.

[Explanation of symbols]

 1 boat 3 hull 6 engine 22 exhaust port 23 exhaust pipe 24 extension end 25 muffler 26 extension end 28 water lock device 35 backflow prevention device 49 exhaust 50 water

Claims (1)

[Claims] 1. A small boat provided with a muffler having one end connected to an exhaust port side of an engine and the other end extending to a position lower than the exhaust port, and a water lock device provided on an extended end side of the muffler. In the exhaust device, a backflow prevention device for preventing water from flowing backward from the water lock device side toward the muffler side is installed between the water lock device and the muffler. Exhaust device for small boats that has a locking device installed side by side in a substantially horizontal direction.