JP2013014279A - Water jet propulsion watercraft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water jet propulsion watercraft having a catalyst arranged close to an engine such that occurrence of trouble with an exhaust system caused by vibrations from the engine can be prevented.SOLUTION: In this water jet propulsion watercraft, a first exhaust pipe 41 is fixed to the engine 3, and is connected to an exhaust port. A damper section reduces the vibrations from the engine. A catalyst unit 42 is connected to the first exhaust pipe. The catalyst unit is attached to the engine through the damper section. A second exhaust pipe includes a first flexible pipe having flexibility, and is connected to the catalyst unit. A water lock 44 is fixed to a hull, and is connected to the second exhaust pipe.

Description

  The present invention relates to a water jet propulsion boat.

  Conventionally, some water jet propulsion boats include a catalyst disposed in an exhaust passage. For example, Patent Document 1 discloses a water vehicle including a catalyst. The catalyst is supported on the intermediate exhaust pipe via a mounting flange. The intermediate exhaust pipe is fixed to the cylinder head of the engine by bolts.

JP 11-11393 A

  By passing the catalyst while the exhaust gas is kept at a high temperature, the processing efficiency of the exhaust gas by the catalyst is improved. For this reason, the path length of the exhaust passage from the engine to the catalyst is preferably shorter. Therefore, in order to arrange the catalyst unit including the catalyst at a position close to the engine, the catalyst unit may be fixed to the engine.

  However, in patent document 1 mentioned above, the intermediate | middle exhaust pipe is being fixed to the cylinder head of the engine with the volt | bolt. For this reason, the vibration of the engine is directly transmitted to the intermediate exhaust pipe and the catalyst. In this case, the catalyst unit is liable to be defective, such as the catalyst being displaced or the catalyst being damaged. The catalyst unit is connected to a water lock. When the water lock is fixed to the hull, even if the catalyst unit vibrates due to vibration from the engine, the water lock is difficult to synchronize with the vibration of the catalyst unit. For this reason, the connection part of a water lock and a catalyst unit becomes easy to be damaged.

  An object of the present invention is to provide a water jet propulsion boat in which a catalyst is disposed in the vicinity of an engine and occurrence of a malfunction of an exhaust system due to vibration from the engine can be suppressed.

  A water jet propulsion boat according to an aspect of the present invention includes a hull, an engine, a jet propulsion unit, a first exhaust pipe, a damper portion, a catalyst unit, a second exhaust pipe, and a water lock. . The engine includes an exhaust port and is accommodated in the hull. The jet propulsion unit is driven by an engine. The jet propulsion unit sucks and injects water around the hull. The first exhaust pipe is fixed to the engine and connected to the exhaust port. The damper portion reduces vibration from the engine. The catalyst unit is connected to the first exhaust pipe. The catalyst unit is attached to the engine via a damper portion. The second exhaust pipe includes a flexible first flexible pipe and is connected to the catalyst unit. The water lock is fixed to the hull and connected to the second exhaust pipe.

  In the water jet propulsion boat according to one aspect of the present invention, the catalyst unit is attached to the engine via the damper portion. For this reason, the catalyst unit is arranged near the engine. Moreover, the vibration transmitted from the engine to the catalyst unit is reduced by the damper portion. Further, the second exhaust pipe is disposed between the catalyst unit and the water lock. The first flexible pipe of the second exhaust pipe has flexibility. For this reason, the vibration difference between the catalyst unit and the water lock is absorbed by the first flexible tube. Thereby, it is suppressed that the connection part of a water lock and a catalyst unit is damaged. Thus, in the water jet propulsion boat according to one aspect of the present invention, the catalyst can be disposed near the engine, and the occurrence of malfunctions in the exhaust system due to vibrations from the engine can be suppressed.

Sectional drawing which shows the whole structure of the water jet propulsion boat which concerns on embodiment of this invention. The side view which shows a part of engine and an exhaust passage. The side view which shows a part of engine and the exhaust passage of the state which removed the exhaust manifold unit. The top view which shows a part of engine and exhaust passage. The side view of front piping. Sectional drawing of a front side piping, a rear side piping, and a joint part. The rear view which shows a part of engine and an exhaust passage. Sectional drawing of a catalyst unit. IX-IX sectional drawing in FIG. The top view of a catalyst unit. The perspective view of a support bracket. The expanded sectional view which shows the attachment structure of a catalyst unit and a support bracket. The figure which looked at engine and a part of exhaust passage from back and upper direction. The figure which shows a part of XIV-XIV cross section in FIG. The top view which shows a part of engine and exhaust passage which concern on other embodiment. The rear view which shows the water lock which concerns on other embodiment. The top view which shows arrangement | positioning of the water lock in the water jet propulsion boat which concerns on embodiment and other embodiment. The top view in the hull of the water jet propulsion boat concerning other embodiments.

  Hereinafter, a water jet propulsion boat according to an embodiment of the present invention will be described with reference to the drawings. In the drawing, FWD indicates the forward direction of the propulsion boat. BWD indicates the reverse direction of the propulsion boat. W indicates the width direction of the water jet propulsion boat, that is, the left-right direction.

  FIG. 1 is a cross-sectional view showing the overall configuration of a water jet propulsion boat 1 according to an embodiment of the present invention. The water jet propulsion boat 1 is a so-called personal watercraft (PWC). The water jet propulsion boat 1 includes a hull 2, an engine 3, an exhaust passage 4, and a jet propulsion unit 5. The hull 2 has a deck 2a and a hull 2b. The engine 3 is housed inside the hull 2. The jet propulsion unit 5 is driven by the engine 3. The exhaust passage 4 guides exhaust gas from the engine 3 to the outside of the hull 2. In other words, the exhaust passage 4 guides exhaust gas from the engine 3 into the water.

  An engine room 2 c is provided inside the hull 2. The engine room 2c houses the engine 3, the fuel tank 6, and the like. A partition plate 2d is disposed at the rear of the engine room 2c. Partition plate 2d is arranged to extend vertically upward from hull 2b. The partition plate 2d partitions the inside of the hull 2 in the front-rear direction. Moreover, the partition plate 2d is configured to suppress the generation of rolls. The roll is a phenomenon in which the hull 2 is twisted about the front-rear direction. A seat 7 is attached to the deck 2a. The seat 7 is disposed above the engine 3. A steering 8 for steering the hull 2 is arranged in front of the seat 7.

  In the following description, directions such as front and rear, right and left, and directions such as inclination refer to the directions when the water jet propulsion boat 1 is viewed from the rider seated on the seat 7 in the posture when floating in still water. To do.

  The engine 3 is an in-line four-cylinder four-stroke engine. The engine 3 has a crankshaft 31. The crankshaft 31 is disposed so as to extend in the front-rear direction. A coupling portion 33 is disposed behind the crankshaft 31. The coupling unit 33 connects the output shaft of the engine 3 and the input shaft of the jet propulsion unit 5. Specifically, the coupling part 33 has a pair of couplings 33a and 33b. The coupling 33a is fixed to the crankshaft 31. The coupling 33b is fixed to an impeller shaft 50 described later. The couplings 33a and 33b connect the crankshaft 31 and the impeller shaft 50. The couplings 33a and 33b transmit the rotation of the crankshaft 31 to the impeller shaft 50.

  In the exhaust passage 4, an exhaust manifold unit 41, a catalyst unit 42, an exhaust pipe portion 43, a water lock 44, and an exhaust pipe 45 are provided. The detailed configuration of the exhaust passage 4 will be described later.

  The jet propulsion unit 5 sucks and injects water around the hull 2. The jet propulsion unit 5 includes an impeller shaft 50, an impeller 51, an impeller housing 52, a nozzle 53, a deflector 54, and a bucket 55. Impeller shaft 50 is arranged to extend rearward from engine room 2c through partition plate 2d. The rear portion of the impeller shaft 50 is led into the impeller housing 52 through the water suction portion 2e of the hull 2. The impeller housing 52 is connected to the rear part of the water suction part 2e. The nozzle 53 is disposed behind the impeller housing 52.

  The impeller 51 is attached to the rear part of the impeller shaft 50. The impeller 51 is disposed inside the impeller housing 52. The impeller 51 rotates with the impeller shaft 50 and sucks water from the water suction part 2e. The impeller 51 ejects the sucked water backward from the nozzle 53. The deflector 54 is disposed behind the nozzle 53. The deflector 54 is configured to change the jetting direction of water from the nozzle 53 to the left-right direction. The bucket 55 is disposed behind the deflector 54. The bucket 55 is configured to be able to change the direction of water injection from the nozzle 53 and the deflector 54 forward.

  FIG. 2 is a side view showing a part of the engine 3 and the exhaust passage 4. FIG. 3 is a side view showing a part of the engine 3 and the exhaust passage 4 in a state where an exhaust manifold unit 41 described later is removed. The engine 3 includes a crankcase 32, a cylinder 34, and a cylinder head 35. The crankcase 32 holds the crankshaft 31 described above. An oil pan 36 is attached to the bottom of the crankcase 32. An oil cooler 37 is disposed on the side of the crankcase 32. An oil pump 38 is attached to the front portion of the crankcase 32. The oil pump 38 is driven by the rotation of the crankshaft 31. The oil pump 38 pumps up the oil in the oil pan 36 and supplies it to the cylinder 34. The oil in the oil pan 36 is cooled in an oil cooler 37. The cylinder 34 and the cylinder head 35 are disposed above the crankcase 32. A power storage control device 39 is disposed on the side of the cylinder 34 and the cylinder head 35. The power storage control device 39 is a device in which a rectifier and a regulator are integrated. The rectifier rectifies an alternating current generated by a generator (not shown) driven by the engine 3 into a direct current. The regulator controls the voltage of power charged in a battery (not shown).

  As shown in FIG. 3, the cylinder head 35 has a plurality of exhaust ports 35a to 35d. In the present embodiment, the cylinder head 35 has first to fourth exhaust ports 35a to 35d. Exhaust gas generated in the engine 3 is discharged from the first to fourth exhaust ports 35a to 35d to the outside of the engine 3. The first to fourth exhaust ports 35 a to 35 d are formed on the side surface of the cylinder head 35. The first to fourth exhaust ports 35 a to 35 d are open toward the side of the engine 3. The first to fourth exhaust ports 35a to 35d are arranged in order from the front to the rear. That is, the first exhaust port 35a is located in the foremost position among the first to fourth exhaust ports 35a-35d. The fourth exhaust port 35d is located most rearward among the first to fourth exhaust ports 35a-35d. A water channel 35e is provided around the first to fourth exhaust ports 35a to 35d. Water pumped up by a water pump (not shown) flows through the water channel 35e.

  FIG. 4 is a plan view showing a part of the engine 3 and the exhaust passage 4. In FIG. 4, the power storage control device 39 shown in FIG. 2 is omitted for easy understanding. The exhaust manifold unit 41 is connected to the engine 3. The exhaust manifold unit 41 is attached to the first to fourth exhaust ports 35a to 35d. The exhaust manifold unit 41 guides exhaust gas discharged from the engine 3. The exhaust manifold unit 41 connects the engine 3 and the catalyst unit 42. The exhaust manifold unit 41 is an example of the “first exhaust pipe” in the present invention. The exhaust manifold unit 41 is fixed to the engine 3. Specifically, the exhaust manifold unit 41 is fixed to the side surface of the cylinder head 35 by a fixing member such as a bolt. The exhaust manifold unit 41 extends in the front-rear direction on one side of the engine 3. The exhaust manifold unit 41 is configured to bend toward the other side of the engine 3 at a position behind the engine 3.

  The exhaust manifold unit 41 includes a front side pipe 61, a rear side pipe 62, and a joint portion 63. The front side pipe 61 is connected to the engine 3. The front pipe 61 is made of a metal such as aluminum. The front piping 61 is configured to extend in the front-rear direction on the side of the engine 3. The front piping 61 is disposed so as to face the side surface of the engine 3. The front piping 61 includes a plurality of branch portions 61a-61d and a trunk portion 61e. The branch portions 61a to 61d are connected to the first to fourth exhaust ports 35a to 35d, respectively. The branch portions 61a-61d are configured to extend laterally from the first to fourth exhaust ports 35a-35d. Specifically, the branch portions 61a-61d are configured to extend from the first to fourth exhaust ports 35a-35d to the side and downward. In the present embodiment, the plurality of branch portions 61a-61d have first to fourth branch portions 61a-61d. The first to fourth branch portions 61a to 61d are arranged in order from the front to the rear. That is, the 1st branch part 61a is located in the forefront among the 1st-4th branch parts 61a-61d. The fourth branch portion 61d is located most rearward among the first to fourth branch portions 61d. The trunk portion 61e is disposed on the side of the engine 3 so as to extend in the front-rear direction. As shown in FIG. 2, the upper surface and the lower surface of the trunk portion 61 e are arranged substantially horizontally in a side view. The diameter of the trunk 61e is generally constant over the front-rear direction. In a side view, the axis AX1 (see FIG. 5) of the trunk 61e is positioned below the first to fourth exhaust ports 35a to 35d.

  FIG. 5 is a side view of the front pipe 61. The trunk portion 61e is configured such that exhaust gases from the plurality of branch portions 61a-61d are collected. Specifically, the first to fourth branch portions 61d are each connected to the trunk portion 61e. The trunk 61e has a plurality of connection ports 61f-61i. Specifically, the connection ports 61f-61i have first to fourth connection ports 61f-61i. The first to fourth connection ports 61f-61i are arranged in order from the front to the rear. That is, the first connection port 61f is located at the foremost position among the first to fourth connection ports 61f-61i. The fourth connection port 61i is located at the rearmost among the first to fourth connection ports 61i. The first connection port 61f is connected to the first branch portion 61a. The second connection port 61g is connected to the second branch portion 61b. The third connection port 61h is connected to the third branch portion 61c. The fourth connection port 61i is connected to the fourth branch part 61d.

  As shown in FIG. 4, the joint portion 63 connects the front side pipe 61 and the rear side pipe 62. The joint part 63 is disposed downstream of the front side pipe 61. The joint part 63 is disposed behind the front side pipe 61. The joint part 63 is made of a flexible material such as rubber. The joint part 63 has a cylindrical shape. The outer diameter of the joint part 63 is larger than the outer diameter of the trunk part 61e. A downstream end portion of the front pipe 61 is inserted into the joint portion 63. Thereby, the front side pipe 61 is connected to the joint portion 63. The joint portion 63 is an example of a “second flexible tube” in an embodiment of the present invention.

  The rear piping 62 is disposed downstream of the joint portion 63. The rear side pipe 62 is disposed behind the joint part 63. The rear piping 62 is configured to bend toward the catalyst unit 42. The rear piping 62 is made of a metal such as aluminum. An upstream end portion of the rear pipe 62 is inserted into the joint portion 63. Thereby, the rear side pipe 62 is connected to the joint part 63.

  FIG. 6 is a cross-sectional view of the front side pipe 61, the joint part 63, and the rear side pipe 62. As shown in FIG. 6, the front pipe 61 has a front inner pipe 61m and a front outer pipe 61n. A water jacket portion 61p through which cooling water flows is formed between the front inner tube 61m and the front outer tube 61n. The downstream end of the front inner pipe 61m protrudes from the downstream end of the front outer pipe 61n. Similarly, the rear pipe 62 has a rear inner pipe 62m and a rear outer pipe 62n. A water jacket portion 62p through which cooling water flows is formed between the rear inner tube 62m and the rear outer tube 62n. The upstream end of the rear inner tube 62m protrudes from the upstream end of the rear outer tube 62n. The joint portion 63 covers the outer surface of the downstream end portion of the front outer tube 61n and the outer surface of the upstream end portion of the rear outer tube 62n. The joint part 63 is fixed to the front outer tube 61n and the rear outer tube 62n by a band 80a with a fastening tool. A step portion 61k is formed at the downstream end of the front inner tube 61m. Further, a stepped portion 62k is formed at the upstream end of the rear inner tube 62m. An L-shaped gap is provided between the step portion 61k of the front inner tube 61m and the step portion 62k of the rear inner tube 62m in a side sectional view. A seal ring 80c is fitted in this gap. The seal ring 80c is made of heat insulating rubber, for example, made of silicon rubber. An elastic ring 80d made of a heat-resistant metal is attached to the seal ring 80c. The elastic ring 80d is formed, for example, by compressing a plurality of stainless wires entangled with each other. A sleeve 80e is placed over the outer surface of the downstream end of the front inner tube 61m and the outer surface of the upstream end of the rear inner tube 62m. The sleeve 80e is formed of a flexible material such as rubber. The sleeve 80e is fixed to the front inner tube 61m and the rear inner tube 62m by a band 80b with a fastener. The water jacket portion 61p of the front pipe 61 and the water jacket portion 62p of the rear pipe 62 communicate with each other through a space 63p between the inner surface of the joint portion 63 and the outer surface of the sleeve 80e. As described above, the water jacket portion 61p of the front pipe 61, the water jacket portion 62p of the rear pipe 62, and the space 63p between the inner surface of the joint portion 63 and the outer surface of the sleeve 80e, A jacket portion 68a is configured. The water jacket portion 61p of the front pipe 61 communicates with the water flow path 35e (see FIG. 3) of the engine 3 described above. Accordingly, the water jacket portion 68 a of the exhaust manifold unit 41 communicates with the water flow path 35 e of the engine 3.

  The catalyst unit 42 is disposed downstream of the rear side pipe 62. The catalyst unit 42 is connected to the exhaust manifold unit 41. The catalyst unit 42 is disposed so as to face the rear surface of the cylinder head 35.

  FIG. 7 is a rear view showing a part of the engine 3 and the exhaust passage 4. FIG. 8 is a cross-sectional view of the catalyst unit 42 on a vertical plane passing through the axis of the catalyst unit 42. The catalyst unit 42 includes a catalyst member 64 and a catalyst housing pipe 65. The catalyst housing pipe 65 houses the catalyst member 64. The catalyst housing pipe 65 is made of a metal such as aluminum. The catalyst housing pipe 65 is an example of the “pipe” of the present invention. The catalyst member 64 is disposed in the exhaust passage 4. The catalyst member 64 promotes the reaction of components (for example, HC, CO, NOx, etc.) contained in the exhaust gas. The catalyst member 64 can efficiently react components (for example, HC, CO, NOx, etc.) contained in the exhaust gas when the temperature is equal to or higher than a predetermined temperature (about 300 ° C.). Therefore, the catalyst member 64 is provided in the vicinity of the first to fourth exhaust ports 35a to 35d of the engine 3 so that the temperature of the exhaust gas reaching the catalyst member 64 does not decrease.

  Specifically, the catalyst unit 42 is disposed so as to face the rear surface of the cylinder head 35 of the engine 3. The catalyst unit 42 is disposed behind the cylinder head 35. The catalyst unit 42 is disposed so as to extend in the width direction in a region facing the rear surface of the cylinder head 35. As shown in FIG. 3, the catalyst unit 42 is disposed at substantially the same height as the first to fourth exhaust ports 35a to 35d. As shown in FIG. 4, the catalyst unit 42 is disposed above the crankshaft 31 of the engine 3. The catalyst unit 42 is disposed so as to overlap with the center line C1 passing through the crankshaft 31 in plan view. Specifically, the front part of the catalyst unit 42 overlaps the rear end part of the crankshaft 31 in plan view.

  The catalyst housing pipe 65 includes a first catalyst housing pipe 66 and a second catalyst housing pipe 67. The second catalyst housing pipe 67 is a separate member from the first catalyst housing pipe 66. The first catalyst housing pipe 66 and the second catalyst housing pipe 67 are arranged side by side in the axial direction of the catalyst unit 42. That is, the first catalyst housing pipe 66 and the second catalyst housing pipe 67 are arranged side by side in the width direction. The first catalyst housing pipe 66 is formed integrally with the rear pipe 62. The second catalyst housing pipe 67 is formed integrally with an upstream pipe 75 of the exhaust pipe section 43 described later.

  As shown in FIG. 8, the catalyst member 64 has a flange portion 64a and a catalyst carrier 64b. The catalyst carrier 64b is a cylindrical member having a honeycomb structure, for example, and supports a catalyst. The catalyst carrier 64b is made of metal, for example, but may be formed of other materials such as ceramic. The flange portion 64a has an annular shape. The flange portion 64a is fixed to the outer peripheral surface of the catalyst carrier 64b. The flange portion 64a is configured to protrude outward in the radial direction from the outer peripheral surface of the catalyst carrier 64b. The catalyst member 64 is held by the catalyst housing pipe 65 by sandwiching the flange portion 64 a between the first catalyst housing pipe 66 and the second catalyst housing pipe 67. The flange portion 64a, the first catalyst housing pipe 66, and the second catalyst housing pipe 67 are fixed to each other by a fixing member such as a bolt.

  The catalyst housing pipe 65 has an enlarged diameter portion 65a, a straight portion 65b, and a reduced diameter portion 65c. The enlarged diameter portion 65 a is located upstream of the catalyst member 64. The enlarged diameter portion 65a has a cross-sectional area that gradually increases toward the downstream. The bottom portion 65d of the inner surface of the enlarged diameter portion 65a is configured to extend horizontally in the width direction. The upper portion 65e of the inner surface of the enlarged diameter portion 65a is inclined downward and upward. The straight line portion 65b is located between the enlarged diameter portion 65a and the reduced diameter portion 65c. The straight portion 65b accommodates the catalyst member 64. The bottom portion 65f of the inner surface of the straight portion 65b is configured to extend horizontally in the width direction. The bottom portion 65f of the inner surface of the linear portion 65b is located below the bottom portion 65d of the inner surface of the enlarged diameter portion 65a. The catalyst member 64 is disposed with a gap with respect to the inner surface of the linear portion 65b. The bottom portion 64c of the catalyst carrier 64b is located at substantially the same height as the bottom portion 65d of the inner surface of the enlarged diameter portion 65a. The reduced diameter portion 65 c is located downstream of the catalyst member 64. The reduced diameter portion 65c has a cross-sectional area that gradually decreases toward the downstream. The bottom portion 65g of the inner surface of the reduced diameter portion 65c is configured to extend horizontally in the width direction. The upper portion 65h of the inner surface of the reduced diameter portion 65c is inclined downward and downward. The bottoms of the inner surfaces of the exhaust manifold unit 41, the catalyst unit 42, and the exhaust pipe portion 43 are configured so that there is no portion that rises downstream.

  A water jacket portion 68 b is formed in the catalyst housing pipe 65. The water jacket portion 68b is disposed between the outer surface and the inner surface of the catalyst housing pipe 65, and constitutes a flow path through which water can pass. The water jacket portion 68b is configured to suppress the catalyst unit 42 from becoming high temperature due to the flow of exhaust gas. The water jacket portion 68b of the catalyst unit 42 communicates with the water jacket portion 68a of the exhaust manifold unit 41 described above. The water jacket portion 68b is configured to surround the periphery of the catalyst member 64 through which the exhaust gas flows. As the water flows through the water jacket portion 68b, the catalyst unit 42 is cooled. 9 is a cross-sectional view taken along the line IX-IX in FIG. As shown in FIG. 9, a water jacket portion 68 c is formed on the flange portion 64 a of the catalyst member 64. The water jacket portion 68 c of the flange portion 64 a communicates with the water jacket portion 68 b of the catalyst housing pipe 65. Thereby, the catalyst member 64 is cooled without water contacting the catalyst support 64b directly. However, as shown in FIG. 9, the water jacket portion 68 c is not formed in a portion of the flange portion 64 a that faces the cylinder head 35. A concave portion 64d is formed in a portion of the flange portion 64a facing the cylinder head 35. The recessed portion 64d has a shape recessed toward the inside of the flange portion 64a. That is, the recessed portion 64 d has a shape that is recessed so as to be separated from the cylinder head 35. With such a shape of the flange portion 64a, the gap between the flange portion 64a and the cylinder head 35 is enlarged.

  As shown in FIGS. 2, 4, and 7, the catalyst unit 42 is supported by the engine 3 via a support bracket 71 and a damper portion 72. The support bracket 71 is an example of a “support member” in an embodiment of the present invention. The support bracket 71 is disposed below the catalyst unit 42. The support bracket 71 is fixed to the engine 3. Specifically, the support bracket 71 is fixed to the crankcase 32 of the engine 3 and the cover member 40 (flyhole magnet cover). The cover member 40 is attached to the rear part of the crankcase 32.

  The damper portion 72 reduces vibration from the engine 3. The damper part 72 has a plurality of rubber dampers 72a to 72d. Specifically, the damper portion 72 includes first to fourth dampers 72a to 72d. The first to fourth dampers 72a to 72d are examples of the “elastic member” in one embodiment of the present invention. As shown in FIG. 4, the first damper 72 a is disposed on the left side of the center line C <b> 1 passing through the crankshaft 31. The second damper 72b is disposed on the right side of the center line C1 passing through the crankshaft 31. The third damper 72c is disposed in front of the first damper 72a. The third damper 72c is disposed on the left side of the center line C1 passing through the crankshaft 31. The fourth damper 72d is disposed in front of the second damper 72b. The fourth damper 72d is disposed on the right side of the center line C1 passing through the crankshaft 31. Further, the first damper 72a and the second damper 72b are disposed behind the central axis C2 (see FIG. 10) of the catalyst member 54. That is, the first damper 72 a and the second damper 72 b are arranged at a position farther from the engine 3 than the central axis C <b> 2 of the catalyst member 54. The third damper 72c and the fourth damper 72d are disposed in front of the central axis C2 of the catalyst member 54. That is, the third damper 72c and the fourth damper 72d are disposed at a position closer to the engine 3 than the central axis C2 of the catalyst member 54.

  The catalyst unit 42 is attached to the support bracket 71 via first to fourth dampers 72a to 72d. The catalyst housing pipe 65 of the catalyst unit 42 includes first to fourth attachment portions 69 a to 69 d for attaching the catalyst housing pipe 65 to the support bracket 71. The first to fourth attachment portions 69a to 69d each have a plate shape. The first to fourth attachment portions 69a to 69d are disposed corresponding to the first to fourth dampers 72a to 72d, respectively. FIG. 10 is a plan view of the catalyst unit 42. As shown in FIG. 10, first to fourth mounting holes 69e to 69h penetrating in the vertical direction are formed in the first to fourth mounting portions 69a to 69d. FIG. 11 is a perspective view of the support bracket 71. As shown in FIG. 11, the support bracket 71 includes first to fourth support portions 71 a to 71 d. The first to fourth support portions 71a to 71d are disposed corresponding to the first to fourth dampers 72a to 72d. Holes 71e-71h through which bolts described later are passed are formed in the first to fourth support portions 71a-71d. The upper surfaces of the first to fourth support portions 71a to 71d have a flat shape and support the first to fourth dampers 72a to 72d.

  FIG. 12 is an enlarged cross-sectional view showing a mounting structure between the catalyst unit 42 and the support bracket 71 via the first damper 72a. The first damper 72a is fitted into the first mounting hole 71a of the first mounting portion 69a. The first damper 72a has a cylindrical shape. An annular groove 72e is formed on the outer peripheral surface of the first damper 72a. The groove 72e meshes with the edge of the first mounting hole 71a. A through hole 72f is formed in the first damper 72a. A metal collar 72g is fitted in the through hole 72f. The bolt 89 is inserted into the washer 72h and the collar 72g, and is screwed into the hole 71e of the first support portion 71a. The attachment structure between the catalyst unit 42 and the support bracket 71 via the second to fourth dampers 72b to 72d is the same as the attachment structure via the first damper 72a. Accordingly, the catalyst unit 42 is attached to the support bracket 71 via the first to fourth dampers 72a to 72d.

  As shown in FIGS. 2 and 7, the support direction of the catalyst unit 42 by the damper portion 72 is the vertical direction. On the other hand, in the catalyst unit 42, the passing direction of the exhaust gas is the horizontal direction. Specifically, in the catalyst unit 42, the passage direction of the exhaust gas is the width direction. Accordingly, the support direction of the catalyst unit 42 by the damper portion 72 is perpendicular to the exhaust gas passage direction in the catalyst unit 42.

  As shown in FIGS. 7 and 10, the outer surface of the catalyst housing pipe 65 of the catalyst unit 42 includes first to fourth recesses 73 a to 73 d. The first to fourth recesses 73a to 73d are positioned above the first to fourth attachment portions 69a to 69d, respectively. That is, the first to fourth recesses 73a to 73d are positioned above the first to fourth mounting holes 69e to 69h, respectively. The first to fourth recesses 73 a to 73 d have a shape that is recessed from the outer surface of the catalyst housing pipe 65 toward the inside of the catalyst housing pipe 65. The first to fourth recesses 73a to 73d are configured to extend upward from the first to fourth attachment portions 69a to 69d, respectively. As shown in FIG. 10, the inner surface of the catalyst housing pipe 65 has first to fourth curved portions 73e-73h. The 1st-4th curved parts 73e-73h are located in the back side of the 1st-4th recessed parts 73a-73d, respectively. The first to fourth curved portions 73e to 73h have a curved shape so as to protrude inward of the catalyst housing pipe 65. The first bending portion 73e and the third bending portion 73g are located upstream of the catalyst member 64. The second curved portion 73f and the fourth curved portion 73h are located downstream of the catalyst member 64. The catalyst member 64 is located between the first curved portion 73e and the second curved portion 73f in the width direction, that is, the exhaust gas passage direction. The catalyst member 64 is located between the third curved portion 73g and the fourth curved portion 73h in the width direction, that is, the exhaust gas passage direction.

  As shown in FIG. 4, the support bracket 71 has a shape in which a portion located above the coupling portion 33 is recessed. Specifically, a recess 71 i is formed in the rear portion of the support bracket 71. The recess 71 i has a shape recessed from the rear portion of the support bracket 71 toward the engine 3. As shown in FIG. 11, the recessed part 71i is located between the 1st support part 71a and the 2nd support part 62b. As shown in FIG. 13, when the engine 3 is viewed from the rear and upper position of the engine 3 or from the rear of the engine 3, the lower position of the support bracket 71 can be easily recognized.

  As shown in FIG. 4, the exhaust pipe portion 43 is disposed downstream of the catalyst unit 42. The exhaust pipe portion 43 guides exhaust gas discharged from the engine 3. The exhaust pipe 43 connects the catalyst unit 42 and the water lock 44. The exhaust pipe portion 43 is an example of a “second exhaust pipe” in an embodiment of the present invention. The exhaust pipe portion 43 is configured to bend backward in the vicinity of the portion connected to the catalyst unit 42. The exhaust pipe portion 43 includes an upstream pipe 75 and a connection pipe 76. As shown in FIG. 8, the upstream pipe 75 is configured to extend downward and laterally and bend toward the connecting pipe 76. The upstream pipe 75 is made of a metal such as aluminum. In the upstream pipe 75, a water jacket portion 68d is formed. The water jacket portion 68 d of the upstream pipe 75 communicates with the water jacket portion 68 b of the catalyst housing pipe 65. The downstream end of the upstream pipe 75 is connected to the connection pipe 76. The connection pipe 76 connects the upstream pipe 75 and the water lock 44.

  FIG. 14 is a diagram illustrating a part of the XIV-XIV cross section in FIG. 4. As shown in FIG. 14, the connection pipe 76 includes a tail pipe 77, an inner pipe 78, and an exhaust hose 79. The tail pipe 77 is connected to the downstream end of the upstream pipe 75. The tail pipe 77 is made of a metal such as aluminum. The tail pipe 77 is fixed to the upstream pipe 75 by a fixing member such as a bolt. The tail pipe 77 is disposed so as to extend in the front-rear direction. A water jacket portion 68 e is formed on the tail pipe 77. The water jacket portion 68e of the tail pipe 77 communicates with the water jacket portion 68d of the upstream pipe 75.

  The exhaust hose 79 is configured to extend from the downstream end of the outer peripheral surface of the tail pipe 77 toward the water lock 44. The exhaust hose 79 is made of a flexible material such as rubber and has a cylindrical shape. The exhaust hose 79 is an example of a “first flexible tube” in an embodiment of the present invention. The downstream end of the tail pipe 77 is inserted into the exhaust hose 79. As a result, the exhaust hose 79 is connected to the tail pipe 77.

  The inner pipe 78 is disposed inside the exhaust hose 79. The inner pipe 78 is disposed so as to extend from the downstream end of the inner peripheral surface of the exhaust hose 79 into the water lock 44. The inner pipe 78 is made of a cylindrical pipe made of metal such as aluminum. A wide-angle portion 78a whose diameter gradually increases toward the distal end side is formed at the distal end portion (downstream end portion) of the inner tube 78. The wide-angle part 78a has a bellmouth-like shape that is smoothly curved. The upstream end of the inner pipe 78 is screwed into the inner surface of the downstream portion of the tail pipe 77. As a result, the inner pipe 78 is fixed to the tail pipe 77. The downstream end of the inner pipe 78 is located inside the water lock 44.

  The outer diameter of the inner pipe 78 is smaller than the inner diameter of the exhaust hose 79. For this reason, a cooling water passage 79 a is formed between the outer peripheral surface of the inner pipe 78 and the inner peripheral surface of the exhaust hose 79. The cooling water passage 79 a communicates with the water jacket portion 68 e of the tail pipe 77. The cooling water passage 79 a communicates with the internal space of the water lock 44.

  As shown in FIG.8 and FIG.14, the bottom part of the inner surface of the exhaust pipe part 43 is comprised so that there may be no part which inclines upward toward downstream. More specifically, the bottom part of the inner surface of the upstream pipe 75 in the exhaust pipe part 43 is configured to incline downward toward the downstream. Further, the bottom of the inner surface of the connection pipe 76 is configured to extend horizontally toward the water lock 44.

  The water lock 44 is disposed such that the longitudinal direction extends in the front-rear direction. The water lock 44 is connected to the downstream end of the exhaust pipe portion 43. Accordingly, the water lock 44 is disposed downstream of the catalyst member 64 in the exhaust passage 4. The water lock 44 is connected to an exhaust pipe 45 (see FIG. 1). The tip of the exhaust pipe 45 is disposed outside the hull 2, and the exhaust gas is discharged from the exhaust pipe 45 to the outside of the hull 2. That is, the exhaust gas is discharged from the exhaust pipe 45 into the water. The water lock 44 is configured to suppress water entering from the exhaust pipe 45 from flowing toward the engine 3 side. The water lock 44 is fixed to the hull 2. As shown in FIG. 2, the lower portion of the water lock 44 is disposed below the lower portion of the catalyst unit 42. Further, as shown in FIG. 7, the width dimension L <b> 1 of the water lock 44 is smaller than the vertical dimension L <b> 2 of the water lock 44.

  As shown in FIG. 14, the water lock 44 is formed in a sealed tank shape. A cylindrical connection 44 a is provided at the upstream end of the water lock 44. The connecting portion 44a is inserted into the exhaust hose 79. Thereby, the downstream end part of the exhaust hose 79 is connected to the connection part 44a. The interior of the water lock 44 is partitioned into an upstream portion and a downstream portion by a partition 81. The partition 81 is composed of a plate member. The partition 81 has a curved shape that is curved so as to protrude toward the downstream side. A pair of partition pipes 82 and 83 are arranged inside the water lock 44. The partition pipes 82 and 83 are arranged with a space in the vertical direction. The partition pipes 82 and 83 penetrate the partition 81. In the lower part of the partition 81, a drain hole 81a is formed. The cooling water accumulated in the upstream portion inside the water lock 44 flows to the downstream portion through the drain hole 81a. A mounting hole 44 b is formed on the upper surface of the water lock 44. The upstream end portion of the exhaust pipe 45 is inserted into the downstream portion of the water lock 44 through the attachment hole 44b. The upstream end of the exhaust pipe 45 extends to the vicinity of the bottom of the water lock 44.

  The water jet propulsion boat 1 according to this embodiment has the following characteristics.

  The exhaust manifold unit 41 is coupled to the catalyst unit 42, and the catalyst unit 42 is disposed so as to face the rear surface of the engine 3. Thereby, the path length of the exhaust passage 4 from the first to fourth exhaust ports 35a to 35d of the engine 3 to the catalyst unit 42 is shortened. As a result, since the high-temperature exhaust gas can be guided to the catalyst unit 42, the catalyst unit 42 can be activated quickly after the engine 3 is started. Thereby, harmful components (for example, HC, CO, NOx, etc.) contained in the exhaust gas can be sufficiently purified by causing the catalyst unit 42 to sufficiently react. Further, by arranging the catalyst unit 42 near the engine 3, it is possible to concentrate heavy objects at the center of the hull in the left-right direction and at the rear side in the front-rear direction. Thereby, the left-right balance of the water jet propulsion boat 1 can be improved. Further, the components of the engine 3 and the exhaust system can be arranged in a compact manner.

  The catalyst unit 42 is supported by the support bracket 71 via the damper portion 72. For this reason, the vibration during driving of the engine 3 can be attenuated by the damper portion 72. That is, it is possible to suppress the vibration of the engine 3 from being directly transmitted to the catalyst unit 42. As a result, it is possible to suppress the occurrence of problems in the catalyst unit 42 such as the displacement of the catalyst member 64 or the damage of the catalyst member 64. In particular, in the structure of the catalyst unit 42 as described above, it is possible to prevent the catalyst carrier 64b and the flange portion 64a from being loosened due to vibration or the catalyst carrier 64b from moving relative to the flange portion 64a due to vibration. .

  The exhaust hose 79 of the exhaust pipe portion 43 has flexibility. Therefore, the vibration difference between the catalyst unit 42 and the water lock 44 is absorbed by the exhaust hose 79. Thereby, it is suppressed that the connection part of the water lock 44 and the catalyst unit 42 is damaged. Moreover, the joint part 63 of the exhaust manifold unit 41 has flexibility. For this reason, the vibration difference between the catalyst unit 42 and the front pipe 61 is absorbed by the joint portion 63. Thereby, it is suppressed that the connection part of the front side piping 61 and the catalyst unit 42 is damaged. As described above, in the water jet propulsion boat 1 according to the present embodiment, the catalyst unit 42 can be disposed near the engine 3 and the occurrence of a malfunction in the exhaust system due to vibration from the engine 3 can be suppressed.

  The first to fourth dampers 72a to 72d are arranged separately on the left and right of the center line C1 passing through the crankshaft 31. For this reason, vibration from the engine 3 is more effectively absorbed by the damper portion 72.

  The catalyst unit 42 is disposed so as to overlap with the center line C1 passing through the crankshaft 31 in plan view. For this reason, the right and left balance of the water jet propulsion boat 1 can be improved.

  The support direction of the catalyst unit 42 by the damper portion 72 is perpendicular to the exhaust gas passage direction in the catalyst unit 42. For this reason, it is possible to suppress displacement of the position of the catalyst member 64 due to the vibration of the catalyst unit 42.

  A recess 71 i is formed in the support bracket 71. For this reason, as shown in FIG. 13, when the engine 3 is viewed from the rear and upper position of the engine 3 or from the rear of the engine 3, the position can be easily visually recognized below the support bracket 71. . Therefore, the support bracket 71 does not hinder when checking the positions of the couplings 33a and 33b. Thereby, workability | operativity when connecting the couplings 33a and 33b can be improved.

  Curved portions 73e-73h are formed on the inner surface of the catalyst housing pipe 65. For this reason, the exhaust gas is guided in the catalyst housing pipe 65 by the curved portions 73e to 73h. In particular, the flow of exhaust gas bends substantially vertically in the rear pipe 62, but is guided toward the center of the catalyst member 64 by the first curved portion 73e. For this reason, it is suppressed that a lot of exhaust gas flows toward a specific part of the catalyst member 64. Thereby, the processing efficiency in the catalyst member 64 can be improved.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of invention.

  In the above embodiment, the catalyst unit 42 is disposed so as to face the rear surface of the engine 3, but the arrangement of the catalyst unit 42 is not limited to this position. For example, as shown in FIG. 15, the catalyst unit 42 may be disposed so as to face the front surface of the engine 3. Alternatively, the catalyst unit 42 may be disposed so as to face the side surface of the engine 3. The number of dampers is not limited to four as in the above embodiment, but may be less than four or more than four. The number of exhaust ports is not limited to four as in the above embodiment, but may be less than four or more than four.

  The shape of the water lock is not limited to the shape as in the above embodiment. For example, as shown in FIG. 16, a cylindrical water lock 84 may be provided. However, when the dimension L1 in the width direction of the water lock 44 is smaller than the dimension L2 in the vertical direction as in the above embodiment, the dimension L1 in the width direction is made smaller than that of the cylindrical water lock 84 having the same volume. Can do. FIG. 17A is a plan view of the water jet propulsion watercraft 10 provided with a cylindrical water lock 84. FIG. 17B is a plan view of the water jet propulsion boat 1 including the water lock 44 similar to that of the above embodiment. As shown in FIG. 17, the protruding distance D2 of the water lock 44 in the width direction from the engine 3 in the above embodiment is smaller than the protruding distance D1 of the cylindrical water lock 44 in the width direction from the engine 3. . As described above, the space for arranging the exhaust system can be reduced in the width direction by the water lock 44 in the above embodiment.

  Although the water jet propulsion boat 1 of the above embodiment is a personal watercraft, the water jet propulsion boat may be a sports boat. For example, the water jet propulsion boat 11 shown in FIG. 18 is a sports boat and includes a plurality of drive devices 12a and 12b. Each drive unit 12a, 12b includes an engine 3, an exhaust passage 4, and a jet propulsion unit 5 similar to those in the above-described embodiment.

  ADVANTAGE OF THE INVENTION According to this invention, while arrange | positioning a catalyst near an engine, the water jet propulsion boat which can suppress generation | occurrence | production of the malfunction of an exhaust system by the vibration from an engine can be provided.

DESCRIPTION OF SYMBOLS 1 Water jet propulsion boat 2 Hull 3 Engine 5 Jet propulsion unit 31 Crankshaft 33 Coupling part 35a-35d 1st-4th exhaust port 41 Exhaust manifold unit 42 Catalyst unit 43 Exhaust pipe part 44 Water lock 63 Joint part 64 Catalyst member 64a flange portion 65 catalyst housing tube 66 first catalyst housing tube 67 second catalyst housing tube 69e-69h first to fourth mounting holes 71 support bracket 71i recess 72 damper portions 72a-72d first to fourth damper 73e first curve Part 79 Exhaust hose 89 bolt

Claims (10)

The hull,
An engine including an exhaust port and housed in the hull;
A jet propulsion unit that is driven by the engine and sucks and injects water around the hull;
A first exhaust pipe fixed to the engine and connected to the exhaust port;
A damper portion for reducing vibration from the engine;
A catalyst unit connected to the first exhaust pipe and attached to the engine via the damper;
A second exhaust pipe including a flexible first flexible pipe connected to the catalyst unit;
A water lock fixed to the hull and connected to the second exhaust pipe;
Water jet propulsion boat with. The first exhaust pipe includes a flexible second flexible pipe,
The water jet propulsion boat according to claim 1. The first exhaust pipe is configured to extend in the front-rear direction on the side of the engine,
The catalyst unit is disposed to face the front or rear surface of the engine.
The water jet propulsion boat according to claim 1. The engine further includes a crankshaft arranged to extend in the front-rear direction,
The damper portion includes a first damper disposed on the left side of the center line passing through the crankshaft, and a second damper disposed on the right side of the center line passing through the crankshaft.
The water jet propulsion boat according to claim 3. The engine further includes a crankshaft arranged to extend in the front-rear direction,
The catalyst unit is disposed so as to overlap with a center line passing through the crankshaft in plan view.
The water jet propulsion boat according to claim 3. The exhaust gas passage direction in the catalyst unit is a horizontal direction,
The support direction of the catalyst unit by the damper portion is perpendicular to the exhaust gas passage direction in the catalyst unit,
The water jet propulsion boat according to claim 1. A coupling portion for connecting the output shaft of the engine and the input shaft of the jet propulsion unit;
A support member fixed to the engine;
Further comprising
The engine supports the catalyst unit via the damper portion and the support member,
The support member has a shape in which a portion located above the coupling portion is recessed,
The water jet propulsion boat according to claim 1. A bolt for attaching the catalyst unit to the engine;
A support member fixed to the engine;
Further comprising
The engine supports the catalyst unit via the damper portion and the support member,
The damper portion includes an elastic member in which a through hole is formed,
The catalyst unit includes a mounting hole into which the elastic member is fitted,
The bolt is inserted into the through hole of the elastic member and fixed to the support member.
The water jet propulsion boat according to claim 1. The catalyst unit includes a catalyst member and a tube body that houses the catalyst member,
The outer surface of the tubular body includes a recess located above the mounting hole,
The inner surface of the tubular body is located on the back side of the recess and has a curved portion that is curved so as to protrude inward of the tubular body.
The water jet propulsion boat according to claim 8. The catalyst unit includes a catalyst member and a tube body that houses the catalyst member,
The catalyst member includes a flange portion;
The tubular body includes a first tubular body and a second tubular body separate from the first tubular body,
The catalyst member is held by the tubular body by sandwiching the flange portion between the first tubular body and the second tubular body.
The water jet propulsion boat according to claim 1.

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