JPH07156885A - Engine cooling structure for water surface traveling ship - Google Patents

Abstract

PURPOSE:To provide an engine cooling structure for a water surface traveling ship by which the muffler side can be cooled sufficiently even by a small quantity of cooling water. CONSTITUTION:In an engine cooling structure for a water surface traveling ship to cool an engine for the water surface traveling ship, which has an engine body for the water surface traveling ship having a cylinder block 21, a cylinder head 22 and a head cover 22a and a muffler 27 of the engine body, by cooling water from a cooling pump 60, a joint 61 is arranged to branch off the cooling water from the cooling pump 60 to the engine body side and the muffler 27 side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling structure for cooling an engine for a marine vessel, and more particularly to an improvement of a cooling structure for improving a cooling effect of cooling water on a muffler side.

[0002]

2. Description of the Related Art Generally, an engine for a marine vessel is provided with an engine body composed of a crankcase, a cylinder block, a cylinder head and the like, and a muffler connected to an exhaust port of the engine body. In the conventional cooling structure for such a watercraft engine, the cooling water from the cooling pump is first supplied to the engine body side to flow in the order of cylinder block → cylinder head → head cover to cool the engine body, and The muffler is cooled by being supplied to the muffler side from the head cover via a ring joint.

[0003]

In the above conventional structure, the cooling water supplied to the muffler side passes through the engine body as described above, and therefore it takes time for the cooling water to reach the muffler. , The muffler may get hot during this time. Further, since the cooling water temperature rises to some extent by passing through the engine body, it is necessary to supply a large amount of cooling water in order to sufficiently cool the muffler.

The present invention has been made in view of the above-mentioned conventional problems, and provides an engine cooling structure for a marine vessel capable of sufficiently cooling the muffler side with a small amount of cooling water in a short time. It is an object.

[0005]

SUMMARY OF THE INVENTION The present invention cools an engine for a marine vessel which comprises an engine body for a marine vessel having a crankcase, a cylinder block, and a cylinder head, and a muffler connected to the engine body. In a cooling structure of an engine for a marine vessel for cooling with cooling water from a pump, cooling water from the cooling pump is supplied to the engine main body side and a muffler side by being branched by cooling water branching means. It is characterized in that a system and a muffler side cooling system are provided.

[0006]

According to the present invention, the cooling water from the cooling pump is
It is branched and supplied to the engine body side and the muffler side via the cooling water branching means. That is, the cooling water to the muffler side is supplied to the muffler by the muffler side cooling system without passing through the engine body side. As a result, the cooling water can be supplied to the muffler in a state where the water temperature is low and in a relatively short time, and as a result, the muffler can be sufficiently cooled with a small amount of cooling water.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 6 are views for explaining an engine cooling structure for a water traveling vessel according to an embodiment of the present invention, and FIGS. 1 and 2 are side and plan views of a water traveling vessel equipped with the engine cooling structure. 3 is a sectional view of a muffler portion of the engine, FIG. 4 is a sectional view taken along line IV-IV of FIG. 3, FIG. 5 is a sectional view taken along line VV of FIG. 3, and FIG. 6 is cooling water of the engine cooling structure. It is a schematic diagram which shows a supply path.

In these figures, a watercraft 1 comprises a hull 2, an engine 3 housed and mounted in the hull 2, and a propulsion unit 4 driven by the engine 3.

The hull 2 is a box-shaped structure in which a lid plate-shaped deck 6 is mounted on a so-called bathtub-shaped hull 5 and both are hermetically joined by a gunnel 7. A steering handle 10 is arranged above the engine 3 on the deck 6. The steering handle 10 is adapted to steer the floating steering vessel 1 left and right by swinging a jet outlet 11 of the propulsion unit 4 described later to the left and right.
A saddle type seat 12 is mounted behind the steering handle 10 of the hull 2.

The engine 3 is a two-cycle parallel three-cylinder engine, which has a cylinder block 21, a cylinder head 22, and a head cover 2 on a crankcase 20.
2a are mounted in this order. Further, a carburetor 23 is connected to the engine 3, and a chamber-like cab cover 24 for reducing intake noise is provided on the upstream side of the carburetor 23.

An air duct 25 is connected to the cab cover 24 and opens downward and introduces air into the cab cover 24. The air duct 25 is
It is arranged on the opposite side of the propulsion unit 4 side with the engine 3 in between, whereby it is possible to prevent water from being sucked into the air duct 25. Further, the air duct 25 has a flat shape (see FIG. 3), whereby the length in the front-rear direction of the engine can be shortened while ensuring the suction area. Further, since the air duct 25 is inclined from the center of the engine when viewed in the crankshaft direction, the opening is apart from the side wall of the hull, so that the water accumulated on the side wall of the hull can be sucked in when the hull falls. It can be prevented.

At the rear end of the crankshaft in the crankcase 20, a coupling (not shown) that engages with a coupling 30 mounted at the tip of a propeller shaft 15 to be described later is mounted.

The propulsion unit 4 has a suction duct 13 disposed in a tunnel-shaped space 2a formed in the rear portion of the hull 2, an impeller 14 disposed in the middle of the duct 13, and a rear end portion thereof. The jet port 11 is arranged so as to be swingable from side to side, and the impeller 14 is rotationally driven by a propeller shaft 15. The arrangement space 2a is opened toward the rear of the hull, and the suction port 13a of the suction duct 13 is opened at the bottom of the hull 2.

A muffler 27 is connected to an exhaust port formed in the cylinder block 21 via a mounting member 40. The muffler 27 is connected to the muffler mounting member 40 and is curved upwardly.
1 and a linear portion 42 that is connected to the curved portion 41 and extends in a substantially straight line obliquely downward. The rear end portion 27a of the linear portion 42 is provided with a water lock 28. Exhaust pipe 27 arranged behind the engine
connected to b. The water lock 28 is provided to prevent water from flowing back from the exhaust pipe 27b during overturning.

The curved portion 41 is composed of an inner pipe 43 arranged inside and an outer pipe 45 arranged outside the inner pipe 43 with a gap 44 serving as a cooling jacket. The straight portion 42 includes an inner pipe 46 connected to the inner pipe 43 of the bending portion 41 and an outer pipe 47 connected to an outer pipe 45 of the bending portion 41. A predetermined gap 48 serving as a cooling jacket is formed between the outer tubes 47 so as to communicate with the gap 44. Further, the outer pipe 47 of the straight portion 42 extends longer than the inner pipe 46 while curving downward, and has a downstream end opening 49 at the tip thereof which is made of a rubber exhaust gas connected to the water clock 28. The hose 50 is connected.

The upstream end portion 66 of the outer tube 45 of the curved portion 41.
An introduction joint 45a for guiding the cooling water into the cooling jacket 44 is provided near the. A discharge joint 45b for discharging a part of the cooling water in the cooling jacket 44 to the outside of the ship is provided on the upper portion of the outer pipe 45, and the cooling water is discharged from the discharge joint 45b. The ship operator can confirm that the cooling water is being supplied.

On the downstream side of the outer pipe 47 of the linear portion 42,
The cooling water in the cooling jacket 48 is transferred to the downstream end opening 49.
Derivation parts 47a for bypassing in the vicinity are provided at two locations. On the other hand, the downstream end opening 49 is formed with two introduction portions 51 for introducing cooling water at two locations that are displaced in the circumferential direction, and each of the lead portions 47a and each of the introduction portions 51 has a rubber bypass hose 52. Connected by. Further, each of the introduction portions 51 is arranged on the side of the downstream end opening portion 49 so as to be inclined downward (see FIG. 3), and as shown in FIG. 4, the tangent line of the substantially circular cross section of the downstream end opening portion 49. Are arranged in the direction. As a result, the cooling water (see the arrow a in FIGS. 3 and 4) introduced from each of the introduction portions 51 swirls along the inner wall of the downstream end opening 49 and the exhaust hose 50 while being directed obliquely downward, That is, the spiral flow is directed downward. for that reason,
The cooling water supplied to the vicinity of the downstream end opening 49 via the bypass hose 52 is suppressed from being diffused and atomized, and as a result, the backflow of the cooling water to the engine side is suppressed.

An annular rubber seal 53 for closing the downstream end opening of the cooling jacket 48 is mounted near the downstream end opening of the inner pipe 46. A notch 53a (see FIG. 5) is partially formed in the upper portion of the seal 53,
The cooling water in the cooling jacket 48 drips into the outer pipe 47 through the notch 53a, and the downstream portion (the muffler rear end portion 27a) of the outer pipe 47 is cooled. Further, a small-diameter throttle portion 46a is formed at the tip of the inner pipe 46. This suppresses the pulse return of the negative pressure wave propagating to the engine side during the exhaust stroke, and the inside of the inner pipe 46 (see FIG. 3).
Even when the outside (B part in the figure) is in a higher pressure state than the outside (A part), the propagation of this pressure state can be suppressed, and as a result, the cooling water introduced into the above A part can be suppressed during the intake stroke of the engine. Backflow into the pipe 46 can be suppressed.

A distribution joint 61 to which the cooling water from the pump 61 is supplied is provided in the middle of the cooling water passage 79 to which the cooling pump 61 is connected. Parts 61a, 61b, 61
c and 61d are provided. The cooling water led out from the lead-out portion 61a is connected to the introduction joint 45a of the outer pipe 45.
Is supplied to the cooling jacket 44 of the muffler 27,
Rubber hose 50 through 48 and bypass hose 52
Is discharged to the outside through the water lock 28 exhaust pipe. In this way, the muffler side cooling system R2 that supplies the cooling water to the muffler side is configured.

On the other hand, the muffler mounting member 40 is provided with joints 62, 63 and 64 for introducing cooling water into the cylinder block 21 of the engine 3. The cooling water derived from each of the derivation parts 61b, 61c, 61d is supplied to each of the joints 62, 63, 64, respectively. The joints 62 and 6
The cooling water supplied to 3, 64 passes through the engine body side, that is, in the cooling jackets in the cylinder block 21 and the cylinder head 22, and is discharged to the outside of the hull from a derivation joint 65 provided at the upper end of the cylinder head 22. It is like this. In this way, the engine body side cooling system R1 that supplies cooling water to the engine body side is configured.

A gasket 78 for separating the cooling water supply passages on the muffler 27 side and the engine body side from each other is attached to the connecting surface between the curved portion 41 of the muffler 27 and the muffler mounting member 40. . Although not shown, the gasket 78 has a plurality of small holes for discharging the cooling water remaining in the muffler 27 after the engine is stopped.

Next, the function and effect of the above embodiment will be described. When the cooling pump 60 is driven, the cooling pump 6
Cooling water is supplied from 0 to the distribution joint 61. The cooling water supplied to the distribution joint 61 is supplied to the introduction joint 45a from the derivation part 61a and the muffler bending part 4
1 is introduced into the cooling jacket 44, and a part thereof is discharged from the discharge joint 45b to the outside of the ship, and also flows into the cooling jacket 48 of the muffler straight portion 42, whereby the muffler 27 is cooled.

The cooling water introduced into the cooling jacket 48 is introduced from the outlet 47a through the bypass hose 52 into the downstream end opening 49 of the outer pipe 47 from the inlet 51. The cooling water introduced into the downstream end opening 49 forms a spiral flow and proceeds downward, whereby the inside of the downstream end opening 49 and the exhaust hose 50 can be cooled.

Further, a part of the cooling water introduced into the cooling jacket 48 passes through the notch 53a of the annular seal 53 attached to the tip of the inner pipe 46 and drops onto the ceiling wall side of the outer pipe 47. Thereby, the tip portion 27a of the outer tube 47 can be cooled.

On the other hand, the cooling water introduced from the cooling pump 60 to the distribution joint 61 is supplied to the outlet portions 61b and 61b.
c, 61d to the respective introduction portions 62 of the muffler mounting member 40,
It is supplied to 63 and 64, cools the inside of the cylinder block 21 and the cylinder head 22, and is discharged out of the ship from the lead-out portion 65 at the upper end of the cylinder head 22.

In this way, the cooling water supplied from the cooling pump 60 is branched and supplied to the engine body cooling system and the muffler 27 side cooling system via the distribution joint 61. Therefore, the cooling water to the muffler 27 side is directly supplied to the muffler 27 without passing through the engine body side, whereby the cooling water is supplied to the muffler 27 at a low water temperature in a relatively short time. As a result, the muffler 27 can be sufficiently cooled with a small amount of cooling water.

[0027]

As described above, in the cooling structure for a watercraft engine according to the present invention, the cooling water branching means is provided so that the engine body side cooling system and the muffler side cooling system are separately provided. It is possible to directly supply the cooling water to the muffler without passing through the engine body side, and to supply the cooling water to the muffler at a low water temperature and in a relatively short time, resulting in a small amount of cooling water. There is an effect that the muffler can be sufficiently cooled.

[Brief description of drawings]

FIG. 1 is a side view of a watercraft equipped with an engine cooling structure for a watercraft according to an embodiment of the present invention.

FIG. 2 is a plan view of the watercraft.

FIG. 3 is a cross-sectional view of a muffler assembly that constitutes the engine for a watercraft.

4 is a sectional view taken along line IV-IV in FIG.

5 is a sectional view taken along line VV of FIG.

FIG. 6 is a schematic diagram showing a cooling water supply path in the engine cooling structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water-running ship 3 Water-running ship engine 21 Cylinder block 22 Cylinder head 22a Head cover 27 Muffler 60 Cooling pump 61 Distribution joint (cooling water branching means) R1 Engine side cooling system R2 Muffler side cooling system

Claims (1)

[Claims] 1. An engine body for a marine vessel, which has a crankcase, a cylinder block, and a cylinder head,
In a cooling structure for a marine vessel engine for cooling an engine for marine vessel composed of a muffler connected to the engine body with cooling water from a cooling pump, cooling water branching means for cooling water from the cooling pump is provided. According to the above, there is provided an engine body side cooling system and a muffler side cooling system, which are branched and supplied to the engine body side and the muffler side, and a cooling structure for an engine for a watercraft.