JP4493873B2 - Water jet propulsion boat - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water jet propulsion boat.
[0002]
[Prior art]
A water jet propulsion boat is propelled by injecting water backward from an injection nozzle of a jet pump (jet propulsion device) driven by an engine. An occupant straddling a straddle-type seat operates a steering handle. By turning the deflector of the injection nozzle from side to side, it turns.
[0003]
[Problems to be solved by the invention]
In such a water jet propulsion boat, when a multi-cylinder engine is installed in the boat, the exhaust passage (independent exhaust passage and collective exhaust passage) is compactly incorporated in the width direction of the narrow engine room, and the length of the independent exhaust passage is It is desired to improve the engine output by suppressing variations in the engine output of each cylinder by making the lengths substantially equal.
[0004]
The present invention has been made to meet the above-mentioned demands, and an object thereof is to provide a water jet propulsion boat that is devised in the exhaust passage layout and can be compactly incorporated in an engine room and can improve engine output. It is what.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides an independent exhaust passage that extends in the front-rear direction on either the left or right side of the engine while being independent of a plurality of exhaust ports formed in a multi-cylinder engine, and the independent exhaust passage. In a water jet propulsion boat having a collective exhaust passage that gathers together , upstream ends of independent exhaust passages are respectively attached to the exhaust ports of the engine, and the independent exhaust passages extend obliquely downward. The portion extending in the front-rear direction and further extending upward to the collecting portion of the collective exhaust passage and extending in the front-rear direction of each independent exhaust passage is arranged substantially in parallel in the vertical direction, and the vertical direction of each independent exhaust passage The portion extending in the direction is provided with a water jet propulsion boat characterized by being arranged substantially in parallel in the front-rear direction .
[0006]
According to the present invention, the portion extending in the front-rear direction of each independent exhaust passage extending in at least one direction of the front-rear direction and the up-down direction on either side of the left and right sides of the multi-cylinder engine independent of the plurality of exhaust ports, Since the portions extending in the front-rear direction can be laid out so that the lateral width is narrow because they are arranged substantially in parallel in the vertical direction, it can be compactly incorporated in a narrow engine room.
[0007]
The phrase “arranged substantially in parallel in the vertical direction” means that at least a part of them overlaps in plan view.
[0008]
Further, vertically extending portion of the independent exhaust passage, from being substantially juxtaposed in the longitudinal direction, since the portions extending in the vertical direction can be laid out such lateral width becomes narrow, as incorporated compactly in a narrow engine room Become.
[0009]
The phrase “arranged substantially in parallel in the front-rear direction” means that at least a portion overlaps in a side view.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0012]
1 to 4 show a first embodiment. A water jet propulsion boat 1 includes a hull member 2 and a deck member 3 that are joined together at the periphery thereof to form a hull 4. A multi-cylinder engine 6 for a propulsion unit is mounted in an engine room 5 formed at a substantially central position in the front-rear direction of the engine. A fuel tank 7 is installed in front of the engine 6 and a jet pump is disposed behind the engine 6. (Jet propulsion device) 8 is installed.
[0013]
Foot steps 3a are formed on both sides of the deck member 3, respectively, while a hatch cover 10 is attached to the front upper portion of the deck member 3, and a steering handle 12 is provided at the rear thereof.
[0014]
A seat base 13 is provided at the rear upper part of the deck member 3, and a straddle-type seat 14 in the front-rear direction is detachably attached to the upper part of the seat base 13. An opening 13a for inspecting the engine 6 in the engine room 5 when the seat seat 14 is removed is formed. Reference numeral 9 denotes a ventilator that ventilates the engine room 5.
[0015]
An impeller shaft 22 is connected to an output shaft 20a linked to the crankshaft 20 of the engine 6 through a coupling 21. An impeller 8b accommodated in the impeller housing 8a of the jet pump 8 is connected to the impeller shaft 22. The injection nozzle 23 is provided at the rear end of the impeller housing 8a, and the deflector 24 is attached to the injection nozzle 23.
[0016]
The occupant straddling the straddle-type seat 14 controls the engine output with the throttle lever of the steering handle 12, and the jet flow generated by the impeller 8b of the jet pump 8 driven by the engine 6 is rearward from the injection nozzle 23. The hull 4 is propelled by jetting, and the steering handle 12 is turned to swing the deflector 24 of the jet nozzle 23 left and right.
[0017]
The engine 6 is, for example, an in-line 2-cylinder four-cycle engine, and is mounted on the hull member 2 of the engine room 5 via an engine mount 25 such that the crankshaft 20 extends in the longitudinal direction of the hull. Inclined to starboard side in rear view.
[0018]
The cylinder block of the engine 6 is provided with a first cylinder 40 and a second cylinder 41 in order from the front to the rear. Since the internal structure of the engine 6 is the same as that of a known technique, a specific description is omitted.
[0019]
An intake box 53 is arranged on the port side of the engine 6, and an intake inlet 54 a of the throttle body 54 for each cylinder 40, 41 is faced to the upper portion of the intake box 53. Thus, air is supplied to the intake port on the port side of the cylinder head 26. In addition, 55 is a fuel injection valve, 56 is a throttle valve.
[0020]
A filter assembly 57 is disposed in the lower portion of the intake box 38, and an intake inlet 58 that opens into the engine room 5 is provided inside the filter assembly 57.
[0021]
On the starboard side of the engine 6, upstream ends of independent exhaust pipes 30 (A, B) communicating with the exhaust ports of the cylinders 40, 41 on the starboard side of the cylinder head 26 are respectively attached. The independent exhaust pipes 30 (A, B) each extend obliquely downward and then forward, and further extend upward to the connecting portion 33.
[0022]
The front part 30a of the first cylinder 40 extending forward of the first independent exhaust pipe 30A is on the lower side, and the part 30b of the second cylinder 41 extending forward of the second independent exhaust pipe 30B is on the upper side. The portions 30a and 30b extending in the vertical direction are arranged substantially in parallel in the vertical direction. That is, a portion 30b extending forward of the second independent exhaust pipe 30B of the exhaust port that is far from a collective portion (connecting portion) 33 of the collective exhaust pipe 32, which will be described later, extends upward and forward of the first independent exhaust pipe 30A. 30a is set on the lower side.
[0023]
In combination with this, in order to make the passage length of each independent exhaust pipe 30 (A, B) substantially equal, the distance to the connecting portion 33 which is the downstream end of each independent exhaust pipe 30 (A, B). Therefore, the portion 30d extending downward of the second independent exhaust pipe 30B is connected to the portion 30b extending forward at substantially the shortest distance, but the portion 30c extending downward of the first independent exhaust pipe 30A is The cylinder head 26 is connected to a portion 30a that is curved forward and extends forward at a long distance.
[0024]
A portion 30g extending upward from the downstream end of the portion 30a extending forward of the first independent exhaust pipe 30A is the front side, and a portion 30h extending upward from the downstream end of the portion 30b extending forward of the second independent exhaust pipe 30B is the rear. The portions 30g and 30h extending upward are arranged substantially in parallel in the front-rear direction so as to be on the side.
[0025]
Each independent exhaust pipe 30 (A, B) is formed with a cooling water jacket 30f. The cooling water jacket 30f is independent before the connecting portion 34, but as shown in FIG. After part 34, they come together.
[0026]
The collective exhaust pipe 32 is curved backward while extending upward from the connecting portion 33 and extends on the starboard side of the cylinder head 26 rearward. The collective exhaust pipe 32 is fixed to the upper portion of the engine 6 with a bracket 45 (see FIG. 3).
[0027]
The connecting portion 33 between the collective exhaust pipe 32 and each independent exhaust pipe 30 (A, B) is also a collective portion in which the independent exhaust pipes 30 (A, B) are gathered together. The collective exhaust pipe 32 in the range L up to the curved portion is formed in an elliptical shape as shown in FIG. 4C, and the rear portion of the range L has a circular shape as shown in FIG. Is formed.
[0028]
A cooling water jacket 32 a that communicates with the cooling water jacket 30 f of each of the independent exhaust pipes 30 (A, B) is formed in the collective exhaust pipe 32, and the cooling water is near the downstream end portion 32 b of the collective exhaust pipe 32. The cooling water in the jacket 32a is discharged into the collective exhaust pipe 32 as indicated by an arrow a.
[0029]
If the passage lengths of the first independent exhaust pipes 30 (A, B) are not substantially equal, as shown in FIG. 4 (e), for example, in front of the collecting portion (connecting portion) 33, In the example, the passage length can be made substantially equal by extending the length of the first independent exhaust pipe 30A by a distance M with respect to the second independent exhaust pipe 30B.
[0030]
The collective exhaust pipe 32 extends obliquely downward from the front side of the bulkhead 15 while extending the starboard side of the cylinder head 26 rearward, and is disposed behind the downstream end 32 b of the collective exhaust pipe 32 and the starboard side of the engine 6. A front opening 35 a of the water lock 35 is connected by a hose 36 that penetrates the bulkhead 15.
[0031]
A discharge pipe 37 whose upstream end is connected to the upper opening 35 b of the water lock 35 bypasses the upper side of the pump chamber 38 of the jet pump 8 from the starboard side to the port side, and is formed on the port side wall of the pump chamber 38. The downstream end is connected.
[0032]
If the layout of the exhaust pipes 30 (A, B), 32 of the first embodiment is used, the front of the first independent exhaust passage 30A and the second independent exhaust pipe 30B communicating with the exhaust ports of the cylinders 40, 41 of the engine 6 will be described. Since the portions 30a and 30b extending in the vertical direction are arranged substantially in parallel in the vertical direction, the layout can be made such that the lateral width W (see FIG. 3) of the portions 30a and 30b extending forward is reduced. It becomes like this.
[0033]
In addition, since the portions 30g and 30h extending upward in the independent exhaust passages 30 (A and B) are arranged substantially in parallel in the front-rear direction, the lateral width W (see FIG. 3) of the portions 30g and 30h extending upward is also narrowed. Thus, it can be compactly incorporated in the narrow engine room 5.
[0034]
Further, a portion 30b extending forward of the second independent exhaust pipe 30B of the exhaust port having a long distance from the collecting portion (connecting portion) 33 of the collective exhaust pipe 32 is an upper portion, and a portion 30a extending forward of the first independent exhaust pipe 30A is provided. Since it is arranged so as to be on the lower side, together with this, the portion 30d extending downward of the second independent exhaust pipe 30B is connected to the portion 30b extending forward at a substantially shortest distance, and the first independent The portion 30c that extends downward of the exhaust pipe 30A is connected to the portion 30a that extends forward by a long distance that is once curved and detoured to the side of the cylinder head 26, thereby allowing the passage of each independent exhaust passage 30 (A, B). Since the length can be made substantially equal, variations in the engine output of the cylinders 40 and 41 are suppressed, and the engine output is improved.
[0035]
5 and 6 show the second embodiment, and the layout of the exhaust pipes 30 (A, B) and 32 different from the first embodiment will be described.
[0036]
On the starboard side of the engine 6, upstream ends of independent exhaust pipes 30 (A, B) communicating with the exhaust ports of the cylinders 40, 41 on the starboard side of the cylinder head 26 are respectively attached. The independent exhaust pipes 30 (A, B) each extend obliquely downward and then extend rearward, and further extend upward to a connecting portion 33 above an oil tank 39 disposed behind the engine 6.
[0037]
Then, each rear part 30a of the first cylinder 40 extending rearward of the first independent exhaust pipe 30A is on the upper side, and a part 30b extending rearward of the second independent exhaust pipe 30B of the second cylinder 41 is on the lower side. The portions 30a and 30b extending in the vertical direction are arranged substantially in parallel in the vertical direction. That is, a portion 30a extending rearward of the first independent exhaust pipe 30A of the exhaust port having a long distance from a collecting portion (connecting portion) 33 of the later-described collective exhaust pipe 32 extends upward and rearward of the second independent exhaust pipe 30B. 30b is set to be on the lower side.
[0038]
In combination with this, in order to make the passage length of each independent exhaust pipe 30 (A, B) substantially equal, the distance to the connecting portion 33 which is the downstream end of each independent exhaust pipe 30 (A, B). Therefore, the portion 30c that extends downward of the first independent exhaust pipe 30A is connected to the portion 30a that extends forward at almost the shortest distance, but the portion 30d that extends downward of the second independent exhaust pipe 30B is The cylinder head 26 is connected to a portion 30b that is bent backward on the side surface side and extends backward at a long distance.
[0039]
A portion 30g extending upward from the downstream end of the portion 30a extending rearward of the first independent exhaust pipe 30A is the front side, and a portion 30h extending upward from the downstream end of the portion 30b extending rearward of the second independent exhaust pipe 30B is the rear. The portions 30g and 30h extending upward are arranged substantially in parallel in the front-rear direction so as to be on the side.
[0040]
The collective exhaust pipe 32 is curved and extends rearward while extending the dead space above the oil tank 39 in the port direction, extends obliquely downward from the front of the bulkhead 15, and the downstream end of the collective exhaust pipe 32. 32 b and a front opening 35 a of a water lock 35 disposed behind the port side of the engine 6 are connected by a hose 36 that penetrates the bulkhead 15.
[0041]
A discharge pipe 37 whose upstream end is connected to the upper opening 35b of the water lock 35 bypasses the upper side of the pump chamber 38 of the jet pump 8 from the port side to the starboard side, and is on the starboard side wall of the pump chamber 38. The downstream end is connected.
[0042]
7 and 8 show a third embodiment, and the layout of the exhaust pipes 30 (A, B) and 32 that are different from the first embodiment will be described.
[0043]
On the starboard side of the engine 6, upstream ends of independent exhaust pipes 30 (A, B) communicating with the exhaust ports of the cylinders 40, 41 on the starboard side of the cylinder head 26 are respectively attached. The independent exhaust pipes 30 (A, B) extend obliquely downward, and then extend rearward to the connecting portion 33 behind the bulkhead 15.
[0044]
Then, each rear part 30a of the first cylinder 40 extending rearward of the first independent exhaust pipe 30A is on the upper side, and a part 30b extending rearward of the second independent exhaust pipe 30B of the second cylinder 41 is on the lower side. The portions 30a and 30b extending in the vertical direction are arranged substantially in parallel in the vertical direction. That is, a portion 30a extending rearward of the first independent exhaust pipe 30A of the exhaust port having a long distance from a collecting portion (connecting portion) 33 of the later-described collective exhaust pipe 32 extends upward and rearward of the second independent exhaust pipe 30B. 30b is set to be on the lower side.
[0045]
In combination with this, in order to make the passage length of each independent exhaust pipe 30 (A, B) substantially equal, the distance to the connecting portion 33 which is the downstream end of each independent exhaust pipe 30 (A, B). Therefore, the portion 30c that extends downward of the first independent exhaust pipe 30A is connected to the portion 30a that extends forward at almost the shortest distance, but the portion 30d that extends downward of the second independent exhaust pipe 30B is The cylinder head 26 is connected to a portion 30b that is bent backward on the side surface side and extends backward at a long distance.
[0046]
The collective exhaust pipe 32 bypasses the upper side of the pump chamber 38 of the jet pump 8 from the starboard side to the port side, and is a water lock disposed behind the downstream end portion 32b of the collective exhaust pipe 32 and the port side of the engine 6. A front upper opening 35 a of 35 is connected by a hose 36.
[0047]
The discharge pipe 37 whose upstream end is connected to the rear upper opening 35b of the water lock 35 bypasses the upper side of the pump chamber 38 of the jet pump 8 from the port side to the starboard side, and the side wall on the starboard side of the pump chamber 38 Is connected to the downstream end.
[0048]
Even with the layout of the exhaust pipes 30 (A, B), 32 of the second and third embodiments, the same operational effects as the first embodiment can be obtained.
[0049]
In each of the above embodiments, the two-cylinder engine 6 is taken as an example, but in the three-cylinder engine 6 as shown in FIGS. 9A and 9B, the front side of the first independent exhaust pipe 30 </ b> A of the first cylinder 40. The portion 30a extending to the bottom is the lowermost side, the portion 30b extending to the front of the second independent exhaust pipe 30B of the second cylinder 41 is the middle, and the portion 30p extending to the front of the third independent exhaust pipe 30C for the third cylinder 42 What is necessary is just to arrange | position the parts 30a, 30b, and 30p extended to each front substantially in parallel up and down so that it may become the uppermost side.
[0050]
Further, in the four-cylinder engine 6 as shown in FIGS. 10A and 10B, the portion 30 a extending forward of the first independent exhaust pipe 30 </ b> A of the first cylinder 40 is the lowest side, and the second cylinder 41 The portion 30b extending forward of the second independent exhaust pipe 30B is on the upper side, and the portion 30p extending forward of the third independent exhaust pipe 30C for the third cylinder 42 is further on the upper side, and the fourth independent exhaust for the fourth cylinder 43 is provided. The forwardly extending portions 30a, 30b, 30p, and 30q may be arranged substantially in parallel in the vertical direction so that the forwardly extending portion 30q of the tube 30D is the uppermost side.
[0051]
【The invention's effect】
As is clear from the above description, the present invention provides a portion extending in the front-rear direction of each independent exhaust passage extending in the front-rear direction on either side of the left or right side of the engine while being independent from a plurality of exhaust ports of the multi-cylinder engine. Since the parts extending in the front-rear direction can be laid out so that the lateral width is narrow, the parts extending in the front-rear direction can be compactly incorporated in a narrow engine room.
[0052]
Further, vertically extending portion of the independent exhaust passage, from being substantially juxtaposed in the longitudinal direction, since the portions extending in the vertical direction can be laid out such lateral width becomes narrow, as incorporated compactly in a narrow engine room Become.
[Brief description of the drawings]
FIG. 1 is a cutaway side view of an essential part of a water jet propulsion boat according to a first embodiment.
FIG. 2 is a cutaway plan view of a main part of FIG.
FIG. 3 is a rear cross-sectional view corresponding to the line AA in FIG. 2;
4A is a side view of an exhaust pipe, FIG. 4B is a cross-sectional view corresponding to the line BB or CC of FIG. 4A, and FIG. 4C is a line DD of FIG. (D) is a cross-sectional view corresponding to the EE line of (a), and (e) is a cross-sectional view in the vicinity of the collective portion of the collective exhaust pipe.
FIG. 5 is a cutaway side view of an essential part of a water jet propulsion boat according to a second embodiment.
6 is a fragmentary plan view of the main part of FIG. 5. FIG.
FIG. 7 is a cutaway side view of an essential part of a water jet propulsion boat according to a third embodiment.
8 is a fragmentary plan view of the main part of FIG. 7. FIG.
FIG. 9 is an independent exhaust pipe of a three-cylinder engine, where (a) is a front view and (b) is a side view.
FIG. 10 shows an independent exhaust pipe of a four-cylinder engine, where (a) is a front view and (b) is a side view.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Water jet propulsion boat 6 Engine 30 (A, B) Independent exhaust pipe 30a, 30b The part 30g extended ahead (or back), The part extended 30h 32 Collective exhaust pipe 33 Collecting part (connecting part)

Claims (1)

An independent exhaust passage (30A, 30B) extending in the front-rear direction on either the left or right side of the engine (6) while being independent of a plurality of exhaust ports formed in the multi-cylinder engine (6) , and the independent exhaust passage (30A , 30B) in a water jet propulsion boat provided with a collective exhaust passage (32) for gathering together,
The upstream ends of the independent exhaust passages (30A, 30B) are respectively attached to the exhaust ports of the engine (6), and the independent exhaust passages (30A, 30B) extend obliquely downward and then extend in the front-rear direction. Further, the portions (30a, 30b) extending upward to the collecting portion (33) of the collecting exhaust passage (32) and extending in the front-rear direction of the independent exhaust passages (30A, 30B) are substantially parallel in the vertical direction. The water jet propulsion boat , wherein the portions (30g, 30h) arranged and extending in the vertical direction of the independent exhaust passages (30A, 30B) are arranged substantially in parallel in the front-rear direction .

Images