JP2909446B2 - Engine and exhaust system cooling system for small personal watercraft - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling system for an engine and exhaust system of a personal watercraft.

[0002]

2. Description of the Related Art In a personal watercraft, a water-cooled engine is usually used because an engine is housed in an engine room. The water cooling method of the engine is generally a direct cooling method having a simple structure.For example, a part of the pressurized water is taken into a water jacket of the engine by a pipe from an opening provided in a water jet propulsion machine and cooled. ing. Further, the water after cooling the engine is discharged into the exhaust system, and is discharged out of the boat together with the exhaust gas through a water muffler constituting a muffler. This also cools the exhaust system (see Japanese Utility Model Publication No. 4-1276).

[0003]

However, in the case of the above-described engine / exhaust-system cooling system, the exhaust gas and the cooling water are mixed by the water muffler, so that the back pressure of the exhaust gas increases and the output of the engine is reduced. Further, when the personal watercraft jumps, the cooling water is not supplied from the water jet propulsion device, so that air enters the cooling water passage and the cooling water hardly flows. Therefore, the temperature of not only the engine but also the flexible rubber pipe used for the connection part of the exhaust system rises. When a catalyst for purifying exhaust gas is installed in the exhaust gas passage of the exhaust system, the temperature of the catalyst may increase due to heat generated by the catalyst, and the exhaust gas purification function may decrease.

A first object of the present invention is to provide an engine / exhaust system cooling device for a personal watercraft that can cool the engine and the exhaust system without causing the back pressure of the exhaust gas to rise. A second object is to provide an engine / exhaust system cooling device for a personal watercraft that can ensure cooling performance of an engine or an exhaust system even when the personal watercraft jumps.

[0005]

To achieve the above first and second object, there is solved a means for the ## engine exhaust system cooling system of claim 1, drives the propulsion device is installed and propulsion device, boat into the body An exhaust system that exhausts exhaust gas from the engine through an exhaust pipe, a muffler, and a tail pipe.
A cooling water passage forming a closed circuit passing through the engine and the exhaust device, a pump for circulating the cooling water in the cooling water passage, and a radiator for cooling the cooling water, wherein at least an exhaust pipe and a muffler of the exhaust device Has a double structure, between which the cooling water passage is formed.

According to the above configuration, since the cooling water is separated from the exhaust gas of the engine, an increase in the back pressure of the exhaust gas due to the mixing with the cooling water can be avoided, and a decrease in the output of the engine can be prevented. Further, since the cooling water passage has a closed circuit, the cooling performance is ensured even when the personal watercraft jumps. Further, at least in the exhaust pipe and the muffler of the exhaust device, the cooling water flows through the outer wall of the double structure,
The cooling water serves as a soundproof wall, and a sufficient noise reduction effect in the exhaust system can be obtained.

Further, in order to achieve the first and second objects, the engine and exhaust system cooling system for a small watercraft according to claim 2, for driving the propulsion unit is installed and propulsion device, boat into the body An engine, an exhaust system that discharges exhaust gas from the engine through an exhaust pipe, a muffler, and a tail pipe, and an engine system cooling water that discharges cooling water taken from a high-pressure section of the propulsion device to the outside of the engine via the engine. A passage, an exhaust system cooling water passage forming a closed circuit passing through the exhaust device, and a pump for circulating cooling water through the exhaust system cooling water passage;
At least the exhaust pipe of the exhaust device and the outer wall of the muffler have a double structure, and the exhaust system cooling water passage is formed therebetween.

According to the above configuration, the engine is cooled by the cooling water taken from the propulsion device and flowing through the engine system cooling water passage. Since the exhaust system is cooled by the cooling water circulating in the exhaust system cooling water passage forming the closed circuit, the cooling performance of the exhaust system is maintained even when the personal watercraft jumps. In addition, since the cooling water flows through the exhaust pipe of the exhaust device and the outer wall of the muffler, the exhaust gas and the cooling water do not mix with each other. Can be prevented. Further, in at least the exhaust pipe and the muffler of the exhaust device, the cooling water flows through the outer wall of the double structure, so that the cooling water serves as a soundproof wall, and a sufficient noise reduction effect in the exhaust system can be obtained.

The engine / exhaust-system cooling device according to claim 3 is
A first check valve that allows the flow of cooling water only from the propulsion device to the engine is mounted in the cooling water passage between the propulsion device and the engine, and a predetermined pressure difference is provided in the cooling water passage downstream of the muffler. It is assumed that a second check valve that opens the valve and allows only the flow of the cooling water out of the boat is mounted. In claim 4, wherein said first check valve between the propulsion unit and the exhaust device, the muffler return valve downstream of the second, are mounted respectively. In claim 5 , the first check valve is mounted between the propulsion device and the engine according to claim 2 , and the second check valve is mounted downstream of the engine.

[0010] According to the arrangement of the preceding claims 3 to 5, when the personal watercraft jumps, since the first and second check valve is closed, the cooling water is retained in the cooling water passage, the cooling Performance is maintained.

According to a sixth aspect of the present invention, there is provided the engine / exhaust system cooling device for a personal watercraft according to the third or fourth aspect , wherein the tail pipe has a double wall structure, and the cooling system is provided therebetween. A water passage is formed, and a cooling water passage downstream of the muffler to which the second check valve is mounted is a cooling water passage of the tail pipe. According to this configuration, the tail pipe of the exhaust device can be cooled with the cooling water, and when the personal watercraft jumps, the cooling water in the cooling water passage of the tail pipe is also held, so that sufficient cooling performance can be obtained. .

According to a seventh aspect of the present invention, there is provided an engine / exhaust system cooling device for a personal watercraft, wherein a first opening / closing valve mounted on a cooling water passage between the propulsion unit and the engine, and a cooling water passage downstream of the muffler. A second opening / closing valve mounted on the engine, pressure detecting means for detecting a water pressure in a cooling water passage supplied to the engine, and the first and second opening / closing valves when the detected water pressure falls below a predetermined pressure. Valve driving means for closing the valve. In claim 8, wherein the first on-off valve between the propulsion unit and the exhaust device, the muffler and the second on-off valve on the downstream side of, are mounted respectively. According to claim 9, wherein the first on-off valve between the propulsion unit and the engine according to claim 2, wherein the second on-off valve on the downstream side of the engine, are mounted respectively.

According to the seventh to ninth aspects, when the personal watercraft jumps, the water pressure detected by the pressure detecting means drops below the predetermined pressure. The valve is closed, the cooling water is held in the cooling water passage, and the cooling performance is maintained.

According to a tenth aspect of the present invention, there is provided an engine / exhaust system cooling device for a personal watercraft, wherein a first opening / closing valve mounted on a cooling water passage between the propulsion unit and the engine, and a cooling water passage downstream of the muffler. A second on-off valve mounted on the vehicle, a rotation speed detecting means for detecting an engine speed, and closing the first and second on-off valves when the detected engine speed rises above a predetermined value. Valve driving means. In claim 11, the first on-off valve between the propulsion unit and the exhaust device, the muffler and the second on-off valve on the downstream side of, are mounted respectively. In claim 12 ,
The first on-off valve is mounted between the propulsion device and the engine according to claim 2 , and the second on-off valve is mounted downstream of the engine.

According to the tenth aspect , when the personal watercraft jumps, the engine speed detected by the speed detecting means rises above a predetermined value. Since the first and second on-off valves are closed, the cooling water is held in the cooling water passage, and the cooling performance is maintained.

According to a thirteenth aspect of the present invention, in the engine / exhaust system cooling device according to the seventh, eighth, tenth, or eleventh aspect , the tail pipe has a double wall structure, and the cooling water passage is formed therebetween. The cooling water passage downstream of the muffler to which the second on-off valve is mounted is a cooling water passage for the tail pipe. According to this configuration, the tail pipe of the exhaust device can be cooled with the cooling water, and when the personal watercraft jumps, the cooling water in the cooling water passage of the tail pipe is also held, so that sufficient cooling performance can be obtained. .

According to a fourteenth aspect of the present invention, there is provided an engine / exhaust system cooling apparatus according to any one of the first to thirteenth aspect , wherein a catalyst for purifying exhaust gas is mounted in the exhaust pipe. According to this configuration, the temperature of the catalyst can be prevented from rising due to its own heat generation, and the exhaust gas purifying function can be maintained at a high level.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 illustrates the principle of the present invention.
FIG. 1 is a side view of a personal watercraft provided with an engine / exhaust-system cooling device as a reference example of the present invention. In FIG. 1, a personal watercraft 1
Is constructed by joining a deck 2b on a hull 2a, and the deck 2b is provided with a seat 2c and a footrest 2d. 2e is a handle. A water jet type propulsion device 3 is mounted on the stern portion, and a shaft 7 of the water jet type propulsion device 3 is connected to a rotation shaft 5 of an engine 4 in the ship via a coupling 6. The rotating shaft 5 is a crankshaft in this example, but may be a separate shaft that is rotatably connected to the crankshaft. The propulsion unit 3 is driven by the engine 4, and the hull 2 is propelled.

FIG. 2 is a plan view showing the installation state of each device except for the deck 2b of the personal watercraft 1. In FIG. 2, reference numeral 8 denotes a fuel tank, which is disposed at the front of the hull 2;
The engine 4 is arranged substantially at the center of the hull 2. An exhaust device 9 for discharging exhaust gas G of the engine 4 outboard and a propulsion device 3 are provided between the engine 4 and the stern.
The cooling water W taken in from the high-pressure section 3a (FIG. 3) of the engine 4 and the exhaust device 9 is separated from the exhaust gas G.
An open-circuit cooling water passage 11 is provided for discharging the water to the outside of the ship via the outside.

FIG. 3A is a partially cutaway side view showing the engine / exhaust-system cooling device of this reference example . The cooling water passage 11 supplies cooling water W taken in from the high-pressure section 3a of the propulsion device 3 to a water jacket (not shown) of the engine 4 to cool the engine 4 and an exhaust device for cooling water W passing through the engine. 9 and the latter half of the water that is discharged outboard. In this example, the high-pressure portion 3a is a portion of a stationary blade 42 located behind an impeller 41 which is a moving blade fixed to the shaft 7. A portion from the propulsion device 3 to the engine 4 in the cooling water passage 11 is formed by a pipe. The exhaust device 9 includes an exhaust pipe 13 connected to an exhaust manifold 12 of a cylinder 10 of the engine 4, a muffler 15 connected downstream of the exhaust pipe 13 via a rubber pipe 14 serving as a connection portion, and an outlet of the muffler 15. It comprises a silencer 16 connected thereto and a tail pipe 17 connecting the silencer 16 to an exhaust port 18 of the stern 2f.

The exhaust pipe 13, rubber pipe 14, muffler 15, muffler 16, and tail pipe 17, which constitute the exhaust device 9, each have a double outer wall, and a cooling water passage 11 is provided between the double outer walls. The latter half of which passes through the exhaust device 9 is formed. The rear half of the cooling water passage 11 branches off from the outer wall of the tail pipe 17, and its drain 19 is located at a lower position away from the exhaust 18 of the stern 2f as seen from the rear side of the hull in FIG. It has an opening. Thereby, the cooling water W taken in from the propulsion device 3
Is discharged outboard via the engine 4 and the exhaust device 9 in a state separated from the exhaust gas G. A catalyst 20 for purifying exhaust gas G is mounted in the muffler 15. In FIG. 3A, a broken line indicates the flow of the cooling water W, and a solid line indicates the flow of the exhaust gas G.

The cooling of the engine 4 and the exhaust system 9 by the engine / exhaust system cooling system configured as described above
This is performed as follows. The cooling water W taken into the cooling water passage 11 from the high-pressure section 3a of the propulsion device 3 is supplied to the engine 4
The water stern 2 f is supplied to a water jacket (not shown), and further passes through cooling water passages 11 formed in the outer wall of an exhaust pipe 13, a rubber pipe 14, a muffler 15, a muffler 16, and a tail pipe 17 which constitute the exhaust device 9. Is discharged out of the ship through the drain port 19 of the ship. Accordingly, the entire path of the exhaust device 9 that exhausts the exhaust gas G of the engine 4 from the exhaust port 18 of the stern 2f to the outside of the stern is cooled. In this case, the cooling water W is discharged outboard through the engine 4 and the exhaust device 9 while being completely separated from the exhaust gas G.
The back pressure of the exhaust gas G does not increase due to the mixing of the cooling water W and the exhaust gas G in the water muffler, and a decrease in the output of the engine 4 due to the cooling water W can be prevented. Further, in the exhaust pipe 13 and the muffler 16 of the exhaust device 9, the cooling water W flows on the outer wall of the double structure, so that the cooling water W becomes a soundproof wall, and a sufficient noise reduction effect in the exhaust system can be obtained. .

In the reference example , since the exhaust gas G is sufficiently cooled in the tail pipe 17 downstream of the exhaust device 9, the cooling water passage 11 in the outer wall of the tail pipe 17 is omitted, and the cooling water The passage 11 may be directly connected from the muffler 16 to the drain port 19 of the stern 2f. Also,
In addition to the case where the drain port 19 is opened at the stern 2f, the drain port 19 may be opened at the front side surface of the hull 2 so that the occupant sitting on the seat 2c of the deck 2b can easily see the discharge state of the cooling water W. Good.

FIG. 4 is a partially cutaway side view showing the engine / exhaust-system cooling device according to the first embodiment of the present invention. The engine / exhaust system cooling device of this embodiment is shown in FIG.
In the engine / exhaust system cooling device shown in FIG. 1, a first check valve 21 that allows the flow of the cooling water W only from the propulsion device 3 to the engine 4 is provided in a portion of the cooling water passage 11 between the propulsion device 3 and the engine 4. And a second reverse portion of the muffler 16, which is the latter half of the cooling water passage 11, is opened at a predetermined pressure difference to allow only the cooling water W to flow outboard. The stop valve 22 is mounted. Other configurations are shown in FIG.
Is the same as

As the check valves 21 and 22, for example, as shown in FIG. 5, a valve seat 23 having a water passage hole 23a provided in the middle of the cooling water passage 11 is provided. The valve seat 2 may have a water passage hole 25a provided in the middle of the cooling water passage 11 as shown in FIG. 6, for example.
5, a piston-shaped valve body 26 that is loosely fitted in the water passage hole 25a, and a spring 27 that elastically supports the head 26a of the valve body 26 from the downstream side.

According to this engine / exhaust system cooling device,
The first and second check valves 21 and 22 are opened by the pressure of the cooling water W taken into the cooling water passage 11 from the high-pressure section 3a of the propulsion device 3 in FIG. 1
1 flows from the engine 4 through the exhaust device 9 and drains 1
Released outboard from 9 Thereby, the same cooling performance as in the case of the engine / exhaust-system cooling device of FIG. 3 is obtained.

On the other hand, when the personal watercraft jumps,
Cooling water W from the high-pressure section 3a of the propulsion device 3 to the cooling water passage 11A
Is not taken in, the water pressure in the cooling water passage 11 decreases, and the first and second check valves 21 and 22 are closed.
Therefore, since the cooling water W is stored between the two check valves 21 and 22, the cooling water is not discharged outboard, and the cooling performance is maintained even when the personal watercraft 1 jumps. By improving the cooling performance in this way, a rise in the temperature of the rubber pipe 14 is also suppressed. Further, the temperature of the catalyst 20 mounted in the muffler 15 is prevented from rising due to its own heat generation,
Exhaust gas purification function can be maintained high.

FIG. 7 is a partially cutaway side view showing an engine / exhaust-system cooling device according to a second embodiment of the present invention. The engine / exhaust system cooling device of this embodiment is similar to that of FIG.
In the engine / exhaust system cooling device shown in FIG. 7, the first and second check valves 21 and 22 are replaced with first and second on-off valves 31,
32, and outputs a closing command signal that is an electric signal when the detected water pressure falls below a predetermined pressure, and a pressure detection unit 33 such as a pressure sensor that detects the water pressure of the cooling water passage 11. , First and second on-off valves 3
A valve driving means 34 for closing the first and second valves 32 is provided.

According to this engine / exhaust system cooling device,
When the cooling water W is taken into the cooling water passage 11 from the high-pressure section 3a of the propulsion device 3, the pressure detecting means 33 detects the water pressure.
Is greater than or equal to a predetermined pressure, and the valve driving means 34 keeps the first and second on-off valves 31 and 32 in the open state. The water is discharged from the drain port 19 to the outside of the ship, and the same cooling performance as that of the engine / exhaust system cooling device shown in FIG. 3 is obtained.

On the other hand, when the personal watercraft jumps,
Since the cooling water W is not taken into the cooling water passage 11 from the high-pressure section 3a of the propulsion device 3, the detected water pressure of the pressure detecting means 33 becomes lower than a predetermined pressure. The second on-off valves 31, 32 are closed. Therefore, the cooling water W in the cooling water passage 11 is not discharged outboard, so that the cooling performance is maintained even when the personal watercraft jumps. The effect at this time is the same as that of FIG.

FIG. 8 is a partially cutaway side view showing an engine / exhaust system cooling device according to a third embodiment of the present invention. The engine / exhaust-system cooling device of this embodiment is shown in FIG.
In the engine / exhaust-system cooling device shown in FIG. 7, a rotation speed detecting means 36 such as an encoder for detecting the rotation speed of the engine 4 shown in FIG. When the engine speed rises above a predetermined value, the first and second on-off valves 31, 32
Is provided with valve driving means 35 for closing the valve.

According to this engine / exhaust system cooling device,
When the propulsion device 3 injects a water jet in a normal running state and the cooling water W is taken into the cooling water passage 11 from the high-pressure portion 3a, the engine 4 is loaded and the rotation speed detecting means 36 Is less than or equal to a predetermined value, and the valve driving means 35 detects the first and second on-off valves 3
1, 32 are kept open. Thereby, the cooling water W
The water is discharged from the engine 4 through the cooling water passage 11 through the exhaust device 9 to the outboard port 19 through the exhaust port 19, and the same cooling performance as that of the engine / exhaust system cooling device shown in FIG. 3 is obtained.

On the other hand, when the personal watercraft jumps,
Since the load on the propulsion device 3 suddenly decreases, the rotation speed of the engine 4 increases, and the rotation speed exceeds a predetermined value. In response to this, the valve driving means 35 causes the first and second opening / closing valves 31, 3 to respond.
2 is closed. Therefore, the cooling water W in the cooling water passage 11 is not discharged outboard, and the cooling performance is maintained even when the personal watercraft jumps. The effect at this time is the same as that of FIG.

FIG. 9A is a partially broken side view showing an engine / exhaust-system cooling device according to a fourth embodiment of the present invention. The engine / exhaust-system cooling device of this embodiment is different from the engine / exhaust-system cooling device shown in FIG.
Water passage 1 forming a closed circuit passing through air and exhaust device 9
1A, and circulates cooling water W through the cooling water passage 11A by a water pump 37 provided in the engine 4 and driven by the rotating shaft 5. Radiator 3 for cooling W
8 is provided. Exhaust pipe 1 constituting exhaust device 9
3, the outer walls of the rubber pipe 14, the muffler 15, the muffler 16, and the tail pipe 17 have a double structure, and the cooling water passage 11A is formed between the outer walls, which is different from the case of the engine / exhaust system cooling device of FIG. The same is true.

The radiator 38 shown in FIG.
And a portion (bottom wall) of which is in contact with water outside the vessel. As shown in FIG. 9B, a partition wall 39 is provided inside the radiator 38 to form a bypass from the inlet 40 of the cooling water W to the outlet 41, and the cooling water W flows evenly in the radiator 38. Is set to

According to this engine / exhaust system cooling device,
The cooling water W is circulated and supplied from the engine 4 to the exhaust device 9 regardless of whether the personal watercraft jumps or is in a landing state, and the cooling water W is always cooled by the radiator 38. Cooling performance is maintained. Other operations are the same as those of the engine / exhaust-system cooling device of FIG.

FIG. 10 is a diagram for explaining the principle of the present invention.
FIG. 4 is a partially cutaway side view showing an engine / exhaust-system cooling device as a reference example . The engine / exhaust system cooling device of this reference example is different from the engine / exhaust system cooling device shown in FIG.
System cooling water passage 11B forming a closed circuit passing through
And the cooling water W taken in from the high-pressure section 3a of the propulsion device 3.
And an exhaust system cooling water passage 11 </ b> C that discharges the exhaust gas from the engine 4 to the outside of the boat via the exhaust device 9 in a state where the exhaust gas G is separated from the exhaust gas G of the engine 4. Cooling water W is circulated in the engine-system cooling water passage 11B of this closed circuit by a water pump 37 provided in the engine 4 and driven by the rotating shaft 5.
Further, the cooling water W is provided in the middle of the engine system cooling water passage 11B.
Is provided with a radiator 48 for cooling.

On the upstream and downstream sides of the exhaust system cooling water passage 11C, as in the case of the engine / exhaust system cooling device shown in FIG. 4, the first and second check valves 51, 51 shown in FIG. 5
2 is installed. Exhaust pipe 1 constituting exhaust device 9
3, the outer walls of the rubber pipe 14, the muffler 15, the muffler 16, and the tail pipe 17 have a double structure, and the exhaust-system cooling water passage 11C is formed between the outer walls. Same as in the case. The arrangement and structure of the radiator 48 of the engine system cooling water passage 11B of FIG. 10 are the same as those of the embodiment of FIG.

According to this engine / exhaust system cooling device,
The cooling water W is circulated and supplied to the engine 4 regardless of whether the personal watercraft jumps or is in a landing state, and the cooling water W is constantly cooled by the radiator 48, so that the cooling performance of the engine 4 is maintained. . The cooling of the exhaust device 9 is performed by cooling water W taken in from the high-pressure section 3 a of the propulsion device 3. Since the first and second check valves 51 and 52 are mounted on the upstream and downstream sides of the exhaust system cooling water passage 11C, when the personal watercraft 1 jumps, the cooling water W is generated by the exhaust system cooling water. It is held in the passage 11C and can prevent the cooling performance from being lowered. Also in this case, the exhaust system cooling water passage 11
Since the cooling water W flowing through C is separated from the exhaust gas G, an increase in the back pressure of the exhaust gas G due to the cooling water W can be avoided, and a decrease in the output of the engine 4 can be prevented.

Instead of the check valves 51 and 52, as shown in FIG.
The opening and closing valves 31 and 32 may be opened and closed according to the engine speed detected by the rotation speed detecting means 36 as shown in FIG. Furthermore, when the cooling performance of the exhaust system during the hull jump can be ignored, the check valves 51 and 52 and the on-off valves 31 and 32 may be omitted.

FIG. 11 is a partially cutaway side view showing an engine / exhaust-system cooling device according to a fifth embodiment of the present invention. The engine / exhaust-system cooling device of this embodiment is different from the open-circuit cooling water passage 11 in the engine / exhaust-system cooling device shown in FIG.
An engine cooling water passage 11D for discharging the cooling water W taken in from the engine through the engine 4 and an exhaust system cooling water passage 11E forming a closed circuit passing through the exhaust device 9 are provided. 11E is provided with a pump 53 for circulating the cooling water W and a radiator 58 similar to the case of the engine cooling water passage 11B in FIG. As the pump 53 in FIG. 11, for example, a water pump installed outside the engine 4 and driven by the rotating shaft 5 can be used. Engine cooling water passage 1
As shown by a chain line in FIG.
Of the deck 2b of the seat 2
The state of discharge of the cooling water W can be easily visually recognized in a state where the user sits on the seat c.

First and second check valves 61 and 62 are mounted on the upstream and downstream sides of the engine cooling water passage 11D, as in the case of the engine / exhaust cooling system shown in FIG. ing. Exhaust pipe 13, rubber pipe 14, muffler 15, muffler 16, tail pipe 17 constituting exhaust device 9
Is formed in a double structure, and an exhaust system cooling water passage 11E is formed between the outer walls as in the case of the engine / exhaust system cooling device of FIG.

According to the engine / exhaust system cooling system shown in FIG. 11, the cooling water W is circulated and supplied to the exhaust system 9 regardless of whether the personal watercraft jumps or is in a landing state. Performance is maintained. The cooling of the engine 4 is performed by the cooling water W taken in from the high-pressure section 3 a of the propulsion device 3. The first and second ports are located upstream and downstream of the engine 4 in the engine cooling water passage 11D.
Are mounted, when the personal watercraft jumps, the cooling water W is maintained in the engine-system cooling water passage 11D , and the engine cooling performance can be prevented from deteriorating.

Instead of the check valves 61 and 62, as shown in FIG.
The opening and closing valves 31 and 32 may be opened and closed according to the engine speed detected by the rotation speed detecting means 36 as shown in FIG. Furthermore, when the cooling performance decrease during the hull jump can be ignored, the check valves 61 and 62 and the on-off valves 31 and 32 may be omitted.

FIG. 12 is a partially cutaway side view showing an engine / exhaust-system cooling device capable of preventing a decrease in cooling performance during a jump. This engine / exhaust-system cooling device has a cooling water passage 11F that discharges cooling water W taken in from the high-pressure section 3a of the propulsion device 3 to the outside of the boat via the engine 4 and the exhaust device 9. The structure of the cooling water passage 11F from the propulsion unit 3 to the muffler 15 of the engine 4 and the exhaust device 9 is the same as that of the cooling water passage 11 in the engine / exhaust system cooling device shown in FIG.

In this engine / exhaust system cooling device, FIG.
The muffler 56 of FIG. 12 is provided in place of the muffler 16 in FIG. 12, and the outer wall of the water muffler 56 and the tail pipe 17 following the water muffler 56 are not of a double structure. The cooling water W sent from the cooling water passage 11F provided on the outer wall of the muffler 14 and the muffler 15
The exhaust gas G is mixed with the water muffler 56 and the tail pipe 17
From the ship. That is, the cooling water passage 11F
Has the same structure as the conventional one. The difference from the related art is that first and second check valves 71 and 72 are mounted on the upstream side and the downstream side of the cooling water passage 11F. That is, in the cooling water passage 11F, the first check valve 71 is mounted on the way from the propulsion device 3 to the engine 4, and the second check valve 72 is mounted on the inlet of the water muffler. Other configurations are the same as those of the engine / exhaust-system cooling device of FIG.

According to this engine / exhaust system cooling device,
Since the exhaust gas G and the cooling water W are mixed in the water muffler 56, the back pressure of the exhaust gas G increases, and the cooling water W
Although the output of the engine 4 is inevitably reduced due to the water flow, when the hull jumps, the check valves 71 and 72 cause
Since the cooling water W is held in F, the cooling performance can be maintained.

[0048]

As described above , according to the first aspect of the present invention, at least the exhaust pipe of the exhaust device and the outer wall of the muffler have a double structure, and the cooling water passage is formed therebetween. Increase in back pressure of exhaust gas caused by
A decrease in engine output can be prevented. Further, since the cooling water passage has a closed circuit, the cooling performance is ensured even when the personal watercraft jumps. Further, in at least the exhaust pipe and the muffler of the exhaust device, the cooling water flows through the outer wall of the double structure, so that the cooling water serves as a soundproof wall, and a sufficient noise reduction effect in the exhaust system can be obtained.

According to the second aspect of the present invention, at least the exhaust pipe of the exhaust device and the outer wall of the muffler have a double structure, and the exhaust system cooling water passage is formed therebetween.
Exhaust gas and cooling water are not mixed, so that an increase in back pressure of the exhaust gas due to the cooling water can be avoided, a decrease in engine output can be prevented, and a sufficient noise reduction effect in the exhaust system can be obtained. Further, since the exhaust system cooling water passage has an open circuit, the cooling performance of the exhaust system is maintained even when the personal watercraft jumps. Further, in at least the exhaust pipe and the muffler of the exhaust device, the cooling water flows through the outer wall of the double structure, so that the cooling water serves as a soundproof wall, and a sufficient noise reduction effect in the exhaust system can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view of a personal watercraft equipped with an engine and exhaust system cooling device as a reference example for explaining the principle of the present invention.

FIG. 2 is a plan view showing an installation state of each device except for the deck of the personal watercraft according to the first embodiment.

FIG. 3A is a partially cutaway side view showing the engine and exhaust system cooling device of the above, and FIG. 3B is a front view of a stern showing an arrangement of an exhaust port and a drain port in the device.

FIG. 4 is a partially broken side view showing the engine / exhaust-system cooling device according to the first embodiment of the present invention .

FIG. 5 is a cross-sectional view showing an example of a check valve used in the engine / exhaust-system cooling device of the above.

FIG. 6 is a sectional view showing another example of the check valve used in the engine / exhaust-system cooling device of the above.

FIG. 7 is a partially cutaway side view showing an engine / exhaust system cooling device according to a second embodiment.

FIG. 8 is a partially broken side view showing an engine / exhaust-system cooling device according to a third embodiment.

9A is a partially cutaway side view showing an engine / exhaust-system cooling device according to a fourth embodiment, and FIG.
It is sectional drawing along the IX-IX line in the inside.

FIG. 10 is a partially cutaway side view showing an engine / exhaust-system cooling device as a reference example for explaining the principle of the present invention .

FIG. 11 is a partially broken side view showing an engine / exhaust-system cooling device according to a fifth embodiment.

FIG. 12 is a partially cutaway side view showing an engine and exhaust system cooling device proposed by the inventor in connection with the present invention.

[Explanation of symbols]

2 ... Hull, 3 ... Propulsion, 3a ... High pressure part, 4 ... Engine,
9: exhaust device, 11, 11A: cooling water passage, 11B, 1
1D: engine system cooling water passage, 11C, 11E: exhaust system cooling water passage, 13: exhaust pipe, 16: muffler, 17: tail pipe, 20: exhaust gas purifying catalyst, 21, 51, 61
... first check valve, 22, 52, 62 ... second check valve, 3
3 ... pressure detecting means, 34, 35 ... valve driving means, 36 ... rotation speed detecting means, 37 ... water pump, 38, 48 ... radiator, 53 ... pump, G ... exhaust gas, W ... cooling water

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-230787 (JP, A) JP-A-9-52593 (JP, A) JP-A-7-61396 (JP, A) 24386 (JP, A) Japanese Utility Model Application Hei 2-60095 (JP, U) Japanese Utility Model Application Showa 59-117831 (JP, U) Japanese Utility Model Application Utility Model No. 2-115792 (JP, U) (58) Field surveyed (Int. ⁶ , DB name) B63H 21/38 B63B 35/73 B63H 21/32

Claims (14)

(57) [Claims] 1. A propulsion device, an engine installed in a hull to drive the propulsion device,
An exhaust device that discharges outboard through a muffler and a tail pipe, a cooling water passage that forms a closed circuit that passes through the engine and the exhaust device, a pump that circulates cooling water through the cooling water passage, and cools the cooling water An engine / exhaust system cooling system for a personal watercraft, comprising: a radiator, wherein at least an exhaust pipe and an outer wall of a muffler of the exhaust device have a double structure, and the cooling water passage is formed therebetween. 2. A propulsion device, an engine installed in the hull for driving the propulsion device, and an exhaust gas from the engine,
An exhaust device that discharges outboard via a muffler and a tail pipe; an engine cooling water passage that discharges cooling water taken in from a high-pressure section of the propulsion device through an engine to the outboard; a closed circuit that passes through the exhaust device And a pump for circulating cooling water through the exhaust system cooling water passage, wherein at least the exhaust pipe and the outer wall of the muffler of the exhaust device have a double structure, between which An engine / exhaust system cooling device for a personal watercraft, wherein the exhaust system cooling water passage is formed. 3. A propulsion device, said propulsion device being installed in a hull.
The engine that drives the machine, and the exhaust gas from the engine
Exhaust system that exhausts outside the ship via silencers and tail pipes
And cooling water taken in from the high-pressure section of the thruster,
Engine and exhaust system separated from exhaust gas
And a cooling water passage to release overboard through, out of at least the exhaust pipe and muffler of the exhaust system
The wall has a double structure, and the cooling water passage is formed between the walls.
A first check valve that allows a flow of cooling water only from the propulsion device to the engine is mounted in a cooling water passage between the propulsion device and the engine; and a predetermined pressure is set in a cooling water passage downstream of the muffler. An engine / exhaust system cooling system for a personal watercraft equipped with a second check valve that opens with a difference and allows only the flow of cooling water outboard. 4. A propulsion device, said propulsion device being installed in a hull.
The engine that drives the machine, and the exhaust gas from the engine
Exhaust system that exhausts outside the ship via silencers and tail pipes
And an engine system forming a closed circuit passing through the engine
Cooling water is circulated through the cooling water passage and the engine system cooling water passage.
The pump to be circulated and taken in from the high-pressure section of the thruster
Through the exhaust system in a state where the cooling water
An exhaust system cooling water passage for discharging to the outside of the ship, wherein at least an exhaust pipe and a muffler of the exhaust device are provided.
The wall has a double structure, and the cooling water passage is formed between the walls.
Is, in the cooling water passage between the exhaust system and the propulsion unit, the first check valve is mounted to permit flow of uncooled water from propulsion unit to the exhaust system, the cooling water passage downstream of the muffler An engine / exhaust-system cooling system for a personal watercraft equipped with a second check valve that opens at a predetermined pressure difference and allows only cooling water to flow out of the boat. 5. The engine according to claim 2 , wherein a first check valve for allowing a flow of cooling water only from the propulsion device to the engine is provided in a cooling water passage between the propulsion device and the engine, and a first check valve is provided downstream of the engine. An engine / exhaust system cooling system for a personal watercraft equipped with a second check valve that opens a cooling water passage at a predetermined pressure difference and allows only the cooling water to flow out of the boat. 6. The muffler according to claim 3 , wherein the tail pipe has a double wall structure, the cooling water passage is formed therebetween, and the second check valve is mounted. A cooling water passage on the downstream side of the tail pipe is a cooling water passage for the tail pipe. 7. A propulsion device, said propulsion device being installed in a hull.
The engine that drives the machine, and the exhaust gas from the engine
Exhaust system that exhausts outside the ship via silencers and tail pipes
And cooling water taken in from the high-pressure section of the thruster,
Engine and exhaust system separated from exhaust gas
And a cooling water passage to release overboard through, out of at least the exhaust pipe and muffler of the exhaust system
The wall has a double structure, and the cooling water passage is formed between the walls.
It is first attached to the cooling water passage between the propulsion unit and the engine
An on-off valve, a second on-off valve mounted on a cooling water passage downstream of the muffler, a pressure detecting means for detecting a water pressure of a cooling water passage supplied to the engine, and An engine / exhaust system cooling system for a personal watercraft, comprising: valve drive means for closing the first and second on-off valves when the pressure drops below a pressure. 8. A propulsion device, said propulsion device being installed in a hull.
The engine that drives the machine, and the exhaust gas from the engine
Exhaust system that exhausts outside the ship via silencers and tail pipes
And an engine system forming a closed circuit passing through the engine
Cooling water is circulated through the cooling water passage and the engine system cooling water passage.
The pump to be circulated and taken in from the high-pressure section of the thruster
Through the exhaust system in a state where the cooling water
An exhaust system cooling water passage for discharging to the outside of the ship, wherein at least an exhaust pipe and a muffler of the exhaust device are provided.
The wall has a double structure, and the cooling water passage is formed between the walls.
It is first attached to the cooling water passage between the exhaust system and the propulsion unit
An on-off valve, a second on-off valve mounted on a cooling water passage downstream of the muffler, pressure detecting means for detecting a water pressure of a cooling water passage supplied to an exhaust device, and a detected water pressure. An engine / exhaust system cooling system for a personal watercraft, comprising: valve drive means for closing the first and second on-off valves when the pressure drops below a predetermined pressure. 9. A valve according to claim 2 , further comprising a first on-off valve mounted on a cooling water passage between said propulsion device and said engine, and a second on-off valve mounted on a cooling water passage downstream of said engine. A pressure detecting means for detecting a water pressure of a cooling water passage supplied to the engine; and a valve driving means for closing the first and second on-off valves when the detected water pressure falls below a predetermined pressure. Engine and exhaust system cooling system for small personal watercraft. 10. A thruster installed in a hull and said thruster.
Engine driving the engine and exhaust gas from the engine
Exhaust to the outside of the ship via pipes, silencers and tail pipes
Gas and cooling water taken in from the high-pressure section of the thruster
The engine and the exhaust gas separated from the exhaust gas.
A cooling water passage for discharging to the outside of the ship via the device, wherein at least an exhaust pipe and a muffler of the exhaust device are provided.
The wall has a double structure, and the cooling water passage is formed between the walls.
It is first attached to the cooling water passage between the propulsion unit and the engine
An on / off valve, a second on / off valve mounted on a cooling water passage downstream of the muffler, a rotation speed detecting means for detecting an engine rotation speed, and the detected engine rotation speed is higher than a predetermined rotation speed. An engine / exhaust system cooling device for a personal watercraft, comprising: valve drive means for closing the first and second opening / closing valves when the vehicle rises. 11. A propulsion device and said thruster installed in a hull.
Engine driving the engine and exhaust gas from the engine
Exhaust to the outside of the ship via pipes, silencers and tail pipes
Air system and an engine forming a closed circuit through the engine
Cooling water to the engine cooling water passage and the engine cooling water passage.
Pump from the high pressure section of the thruster
The exhaust system is separated from the cooling water
After an exhaust system coolant passage to release overboard, the outer at least the exhaust pipe and muffler of the exhaust system
The wall has a double structure, and the cooling water passage is formed between the walls.
It is first attached to the cooling water passage between the exhaust system and the propulsion unit
An on / off valve, a second on / off valve mounted on a cooling water passage downstream of the muffler, a rotation speed detecting means for detecting an engine rotation speed, and the detected engine rotation speed is higher than a predetermined rotation speed. An engine / exhaust system cooling device for a personal watercraft, comprising: valve drive means for closing the first and second opening / closing valves when the vehicle rises. 12. A valve according to claim 2 , further comprising a first on-off valve mounted on a cooling water passage between said propulsion device and the engine, and a second on-off valve mounted on a cooling water passage downstream of said engine. A small-sized skid comprising: a rotational speed detecting means for detecting an engine rotational speed; and a valve driving means for closing the first and second on-off valves when the detected engine rotational speed exceeds a predetermined rotational speed. Engine and exhaust system cooling system for boats. 13. The tail pipe according to claim 7, 8, 10 or 11 , wherein the tail pipe has a double wall structure, the cooling water passage is formed therebetween, and the second on-off valve is mounted. The cooling water passage downstream of the muffler is the cooling water passage of the tail pipe,
Exhaust system cooling device. 14. The engine / exhaust system cooling system for a personal watercraft according to claim 1 , wherein a catalyst for purifying exhaust gas is mounted in the exhaust pipe.