Patent Application
20250171128
This application claims the benefit of priority to Japanese Patent Application No. 2023-202261 filed on Nov. 29, 2023. The entire contents of this application are hereby incorporated herein by reference.
The present invention relates to marine vessels and marine engine cooling systems.
A small marine vessel including a cooling flow passage through which cooling water flows to cool an engine is known in general. Such a marine vessel is disclosed in Japanese Patent Laid-Open No. 2006-009635, for example.
Japanese Patent Laid-Open No. 2006-009635 discloses a small marine vessel including a cooling flow passage through which cooling water flows to cool an engine including a cylinder block, etc.
Although not described in Japanese Patent Laid-Open No. 2006-009635, in a small marine vessel as described in Japanese Patent Laid-Open No. 2006-009635, when cooling water is stagnant in a flow passage portion in a cylinder block when the engine is stopped, the cylinder block may rust, or the cooling water may freeze when the small marine vessel is in a cold environment. Japanese Patent Laid-Open No. 2006-009635 does not particularly disclose a structure to reduce or prevent stagnation of cooling water in a flow passage portion in the cylinder block when the engine is stopped. Therefore, it has been desired to reduce or prevent stagnation of cooling water in the flow passage portion in the cylinder block when the engine is stopped.
Example embodiments of the present invention provide marine vessels and marine engine cooling systems that each reduce or prevent stagnation of cooling water in flow passage portions in cylinder blocks when engines are stopped.
A marine vessel according to an example embodiment of the present invention includes a hull, an engine in the hull including an exhaust manifold, a cylinder head, and a cylinder block, a cooling flow passage to allow cooling water to flow therethrough to cool the engine, and a thermostat in a vicinity of or adjacent to a cooling water outlet of the cylinder block to adjust a flow rate of the cooling water discharged from the cylinder block based on a temperature of the cooling water. The cooling flow passage is operable to allow the cooling water that has flowed through the exhaust manifold to flow into the cylinder block via the cylinder head, and to allow the cooling water to flow into the cylinder block from a lower side of the cylinder block via a lower end flow passage port in a vicinity of or adjacent to a lower end of a flow passage portion in the cylinder block.
In a marine vessel according to an example embodiment of the present invention, the cooling flow passage is operable to allow the cooling water to flow into the cylinder block from the lower side via the lower end flow passage port in the vicinity of or adjacent to the lower end of the flow passage portion in the cylinder block. Accordingly, the flow passage connected to the cylinder block via the lower end flow passage port extends downward, and thus water is drained from the flow passage portion in the cylinder block via the lower end flow passage port when the engine is stopped. Consequently, stagnation of cooling water in the flow passage portion provided in the cylinder block is reduced or prevented when the engine is stopped.
Furthermore, in a marine vessel according to an example embodiment of the present invention, the cooling flow passage is operable to allow the cooling water that has flowed through the exhaust manifold to flow into the cylinder block via the cylinder head, and the marine vessel includes the thermostat in the vicinity of or adjacent to the cooling water outlet of the cylinder block to adjust the flow rate of the cooling water discharged from the cylinder block based on the temperature of the cooling water. Accordingly, the cooling water flows into the cylinder block via the cylinder head, and thus an excessive decrease in the temperature of the cooling water flowing into the cylinder block is reduced or prevented. Furthermore, the thermostat adjusts the temperature of the cooling water flowing through the flow passage portion provided in the cylinder block to an appropriate temperature. Consequently, excessive cooling of the cylinder block is reduced or prevented.
In a marine vessel according to an example embodiment of the present invention, the engine preferably includes an oil cooler, and the cooling flow passage is preferably operable to allow the cooling water that has flowed through the oil cooler to flow into the cylinder block from the lower side via the lower end flow passage port. Accordingly, the flow passage that allows the cooling water that has cooled the oil cooler to flow into the cylinder block is able to be used as a flow passage that allows water to be drained from the flow passage portion provided in the cylinder block via the lower end flow passage port when the engine is stopped. Consequently, as compared with a case in which a dedicated flow passage is provided to drain water, the structure of the cooling flow passage is simplified.
In a marine vessel according to an example embodiment of the present invention, the cooling flow passage is preferably operable to allow the cooling water that has flowed through the cylinder head to be discharged to an outside of the cylinder head via an upper end flow passage port in a vicinity of or adjacent to an upper end of a flow passage portion in the cylinder head. Accordingly, the upper end flow passage port is located in the vicinity of or adjacent to the upper end of the flow passage portion provided in the cylinder head, and thus air mixed in the cooling water is able to be included in the cooling water discharged from the flow passage portion provided in the cylinder head via the upper end flow passage port. That is, air is bled from the cooling water flowing through the flow passage portion provided in the cylinder head via the upper end flow passage port. Consequently, a decrease in the cooling performance of the cooling water flowing through the cooling flow passage due to air being mixed into the cooling water is reduced or prevented.
A marine vessel in which the cooling water that has flowed through the cylinder head is discharged to the outside of the cylinder head via the upper end flow passage port preferably further includes a rectifier/regulator used to control the engine, and the cooling flow passage is preferably operable to allow the cooling water discharged to the outside of the cylinder head via the upper end flow passage port to be discharged to an outside of the hull via the rectifier/regulator. Accordingly, the flow passage that allows air to bleed from the cooling water flowing through the flow passage portion provided in the cylinder head via the upper end flow passage port is able to be used as a flow passage that allows the cooling water discharged from the flow passage portion provided in the cylinder head to flow into the rectifier/regulator to cool the rectifier/regulator. Consequently, as compared with a case in which a dedicated flow passage is provided to bleed air, the structure of the cooling flow passage is simplified.
In a marine vessel in which the cooling water that has flowed through the cylinder head is discharged to the outside of the cylinder head via the upper end flow passage port, the cooling flow passage is preferably operable to allow a portion of the cooling water that has flowed through the cylinder head to flow into the cylinder block, and allow a remaining portion of the cooling water that has flowed through the cylinder head to be discharged to the outside of the cylinder head via the upper end flow passage port. Accordingly, an excessive increase in the number of flow passages for the cooling water discharged from the cylinder head is reduced or prevented, and thus the structure of the cooling flow passage is simplified.
In a marine vessel according to an example embodiment of the present invention, the cooling flow passage preferably includes a flow passage connecting the cylinder head to the cylinder block that has a cross-sectional area smaller than a cross-sectional area of a flow passage connecting the exhaust manifold to the cylinder head. Accordingly, the cross-sectional area of the flow passage connecting the cylinder head to the cylinder block is relatively small, and thus an excessive increase in the flow rate of the cooling water flowing from the flow passage portion provided in the cylinder head into the flow passage portion provided in the cylinder block is reduced or prevented. Consequently, a structure that reduces or prevents excessive cooling of the cylinder block is easily achieved.
In a marine vessel in which the cooling water that has flowed through the cylinder head is discharged to the outside of the cylinder head via the upper end flow passage port, the cooling flow passage preferably includes a flow passage connected to the cylinder head via the upper end flow passage port that has a cross-sectional area smaller than a cross-sectional area of a flow passage connecting the exhaust manifold to the cylinder head. Accordingly, the cross-sectional area of the flow passage connected to the cylinder head via the upper end flow passage port is relatively small, and thus an excessive increase in the flow rate of the cooling water discharged from the cylinder head via the upper end flow passage port is reduced or prevented. Consequently, the possibility is reduced or prevented that the flow rate of the cooling water flowing from the flow passage portion provided in the cylinder head into the flow passage portion provided in the cylinder block is excessively decreased such that the cylinder block is not able to be appropriately cooled.
In a marine vessel according to an example embodiment of the present invention, the cooling flow passage preferably includes a flow passage connected to the cylinder head via the upper end flow passage port that has a cross-sectional area smaller than a cross-sectional area of a flow passage connecting the cylinder head to the cylinder block. Accordingly, an excessive decrease in the cross-sectional area of the flow passage connecting the cylinder head to the cylinder block is reduced or prevented. Consequently, the possibility is reduced or prevented that the flow rate of the cooling water flowing from the flow passage portion provided in the cylinder head into the flow passage portion provided in the cylinder block is excessively decreased such that the cylinder block is not able to be appropriately cooled.
In a marine vessel according to an example embodiment of the present invention, the cooling flow passage preferably includes a flow passage connected to the cylinder block via the lower end flow passage port that has a cross-sectional area smaller than a cross-sectional area of a flow passage connecting the cylinder head to the cylinder block. Accordingly, an excessive decrease in the cross-sectional area of the flow passage connecting the cylinder head to the cylinder block is reduced or prevented. Consequently, the possibility is reduced or prevented that the flow rate of the cooling water flowing from the flow passage portion provided in the cylinder head into the flow passage portion provided in the cylinder block is excessively decreased such that the cylinder block is not able to be appropriately cooled.
In a marine vessel in which the cooling water that has flowed through the oil cooler flows into the cylinder block from the lower side via the lower end flow passage port, the cooling flow passage is preferably operable to allow a portion of the cooling water that has flowed in from outside the hull to flow into the exhaust manifold, and allow a remaining portion of the cooling water that has flowed in from outside the hull to flow into the oil cooler. Accordingly, as compared with a case in which a portion of the cooling water that has flowed in from outside the hull flows into the exhaust manifold, another portion of the cooling water that has flowed in from outside the hull flows into the oil cooler, and the remaining portion of the cooling water that has flowed in from outside the hull flows into components of the marine vessel other than the exhaust manifold and the oil cooler, an excessive decrease in the flow rate of the cooling water flowing into the exhaust manifold is reduced or prevented, and thus the exhaust manifold, which becomes relatively hot, is sufficiently cooled.
In a marine vessel according to an example embodiment of the present invention, the thermostat is preferably operable to adjust the flow rate of the cooling water discharged from the cylinder block such that the temperature of the cooling water becomes a predetermined temperature of about 50 degrees or more and about 70 degrees or less. Accordingly, the temperature of the cooling water flowing through the flow passage portion provided in the cylinder block is easily adjusted to an appropriate temperature. Consequently, a structure that reduces or prevents excessive cooling of the cylinder block is easily achieved.
In a marine vessel according to an example embodiment of the present invention, the cooling flow passage is preferably operable to allow all of the cooling water that has flowed through the exhaust manifold to flow into the cylinder head. Accordingly, the flow rate of the cooling water flowing into the cylinder head is relatively increased, and thus the cylinder head, which becomes relatively hot, is sufficiently cooled.
A marine vessel according to an example embodiment of the present invention preferably further includes a jet propulsion thruster to generate a thrust using a driving force of the engine. Accordingly, in the jet propulsion marine vessel, excessive cooling of the cylinder block is reduced or prevented, and stagnation of cooling water in the flow passage portion provided in the cylinder block is reduced or prevented when the engine is stopped.
A marine engine cooling system according to an example embodiment of the present invention includes a cooling flow passage to allow cooling water to flow therethrough to cool an engine in a hull and including an exhaust manifold, a cylinder head, and a cylinder block, and to allow the cooling water that has flowed through the exhaust manifold to flow into the cylinder block via the cylinder head, and a thermostat in a vicinity of or adjacent to a cooling water outlet of the cylinder block to adjust a flow rate of the cooling water discharged from the cylinder block based on a temperature of the cooling water. The cooling flow passage is operable to allow the cooling water to flow into the cylinder block from a lower side of the cylinder block via a lower end flow passage port in a vicinity of or adjacent to a lower end of a flow passage portion in the cylinder block.
In a marine engine cooling system according to an example embodiment of the present invention, the cooling flow passage is operable to allow the cooling water to flow into the cylinder block from the lower side via the lower end flow passage port in the vicinity of or adjacent to the lower end of the flow passage portion in the cylinder block. Accordingly, similarly to the marine vessel according to example embodiments of the present invention described above, stagnation of cooling water in the flow passage portion provided in the cylinder block is reduced or prevented when the engine is stopped.
Furthermore, in a marine engine cooling system according to an example embodiment of the present invention, the cooling flow passage is operable to allow the cooling water that has flowed through the exhaust manifold to flow into the cylinder block via the cylinder head, and the hull includes the thermostat in the vicinity of or adjacent to the cooling water outlet of the cylinder block to adjust the flow rate of the cooling water discharged from the cylinder block based on the temperature of the cooling water. Accordingly, similarly to the marine vessel according to example embodiments of the present invention described above, excessive cooling of the cylinder block is reduced or prevented.
In a marine engine cooling system according to an example embodiment of the present invention, the engine preferably includes an oil cooler, and the cooling flow passage is preferably operable to allow the cooling water that has flowed through the oil cooler to flow into the cylinder block from the lower side via the lower end flow passage port. Accordingly, similarly to the marine vessel according to example embodiments of the present invention described above, as compared with a case in which a dedicated flow passage is provided to drain water, the structure of the cooling flow passage is simplified.
In a marine engine cooling system according to an example embodiment of the present invention, the cooling flow passage is preferably operable to allow the cooling water that has flowed through the cylinder head to be discharged to an outside of the cylinder head via an upper end flow passage port in a vicinity of or adjacent to an upper end of a flow passage portion in the cylinder head. Accordingly, similarly to the marine vessel according to example embodiments of the present invention described above, a decrease in the cooling performance of the cooling water flowing through the cooling flow passage due to air being mixed into the cooling water is reduced or prevented.
In a marine engine cooling system in which the cooling water that has flowed through the cylinder head is discharged to the outside of the cylinder head via the upper end flow passage port, the hull preferably includes a rectifier/regulator to control the engine, and the cooling flow passage is preferably operable to allow the cooling water discharged to the outside of the cylinder head via the upper end flow passage port to be discharged to an outside of the hull via the rectifier/regulator. Accordingly, similarly to the marine vessel according to example embodiments of the present invention described above, as compared with a case in which a dedicated flow passage is provided to bleed air, the structure of the cooling flow passage is simplified.
In a marine engine cooling system in which the cooling water that has flowed through the cylinder head is discharged to the outside of the cylinder head via the upper end flow passage port, the cooling flow passage is preferably operable to allow a portion of the cooling water that has flowed through the cylinder head to flow into the cylinder block, and allow a remaining portion of the cooling water that has flowed through the cylinder head to be discharged to the outside of the cylinder head via the upper end flow passage port. Accordingly, similarly to the marine vessel according to example embodiments of the present invention described above, the structure of the cooling flow passage is simplified.
In a marine engine cooling system according to an example embodiment of the present invention, the cooling flow passage preferably includes a flow passage connecting the cylinder head to the cylinder block that has a cross-sectional area smaller than a cross-sectional area of a flow passage connecting the exhaust manifold to the cylinder head. Accordingly, similarly to the marine vessel according to example embodiments of the present invention described above, a structure that reduces or prevents excessive cooling of the cylinder block is easily achieved.
In a marine engine cooling system in which the cooling water that has flowed through the cylinder head is discharged to the outside of the cylinder head via the upper end flow passage port, the cooling flow passage preferably includes a flow passage connected to the cylinder head via the upper end flow passage port that has a cross-sectional area smaller than a cross-sectional area of a flow passage connecting the exhaust manifold to the cylinder head. Accordingly, similarly to the marine vessel according to example embodiments of the present invention described above, the possibility that the cylinder block is not able to be appropriately cooled is reduced or prevented.
The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the example embodiments with reference to the attached drawings.
Example embodiments of the present invention are hereinafter described with reference to the drawings.
A marine vessel 100 and a marine engine cooling system 110 according to example embodiments of the present invention are now described with reference to
As shown in
The engine 20 includes a crankshaft 21. The engine 20 obtains a driving force to rotate the crankshaft 21 by burning a mixture of air drawn in through an intake passage (not shown) including a throttle valve (not shown) and fuel in a combustion chamber.
The thruster 30 is driven by the engine 20 to take water into a water passage 31 including an opening on the lower surface of the rear of the marine vessel 100, and to eject the taken-in water from a nozzle 32 located at a rear end of the marine vessel 100. Consequently, the marine vessel 100 is propelled.
The thruster 30 includes a drive shaft 33, an impeller 34, the nozzle 32, a deflector 35, and a reverse gate (bucket) 36.
The drive shaft 33 extends in a forward-rearward direction, and includes a front end connected to the crankshaft 21 and a rear end in the water passage 31. The impeller 34 is fixed to a vicinity of the rear end of the drive shaft 33.
The impeller 34 rotates together with the drive shaft 33 to generate a flow toward the nozzle 32 within the water passage 31.
The nozzle 32 is located at the most downstream location in the water passage 31. The nozzle 32 functions as a water outlet (jetting port). In other words, the nozzle 32 ejects water to generate a propulsive force. The deflector 35 and the reverse gate 36 are provided on the nozzle 32.
The deflector 35 is rotatable in a right-left direction about an axis extending in an upward-downward direction. That is, the deflector 35 is operable to change the direction of the water ejected from the nozzle 32 in the right-left direction.
The reverse gate 36 is rotatable in the upward-downward direction about an axis extending in the right-left direction. In other words, the reverse gate 36 is operable to change the direction of the water ejected from the nozzle 32 in the forward-rearward direction.
As shown in
The engine 20 includes an oil cooler 27. The oil cooler 27 cools lubricating oil used in the engine 20.
The marine vessel 100 includes a rectifier/regulator 41. The rectifier/regulator 41 is used to control the engine 20.
The engine 20 includes a cover 26. The cover 26 is attached to an upper portion of the cylinder head 22. As shown in
The first housing 26a and the second housing 26b are made of a plant-derived cellulose nanofiber (CNF) reinforced resin, for example. The plant-derived cellulose nanofiber reinforced resin is a high-strength material produced by kneading and dispersing plant-derived cellulose nanofiber, which is a biomass material using ligneous resources, into a resin such as polypropylene. The first housing 26a and the second housing 26b may be made of another material. Alternatively, the first housing 26a and the second housing 26b may be made of different materials.
As shown in
Water (such as seawater or fresh water) outside the hull 10 is supplied as cooling water into the cooling flow passage 50 by a jet pump 51. The jet pump 51 is provided between the impeller 34 (see
Through the cooling flow passage 50, a portion of the cooling water that has flowed in from outside the hull 10 flows into the exhaust manifold 24, and the remaining portion of the cooling water that has flowed in from outside the hull 10 flows into the oil cooler 27. Specifically, a joint 52 is provided downstream of the jet pump 51 to branch the cooling flow passage 50 into a flow passage toward the exhaust manifold 24 and a flow passage toward the oil cooler 27.
The marine vessel 100 (marine engine cooling system 110) includes a water flusher 53. The water flusher 53 includes an adapter to which a water hose is attachable. When the cooling flow passage 50 is flushed with water, the water hose is attached to the adapter of the water flusher 53.
Through the cooling flow passage 50, all of the cooling water that has flowed through the exhaust manifold 24 flows into the cylinder head 22. Specifically, through the cooling flow passage 50, all of the cooling water that has flowed through a flow passage portion 24a provided in the exhaust manifold 24 flows into a flow passage portion 22a provided in the cylinder head 22 without passing through other portions of the marine vessel 100 that are to be cooled. As shown in
As shown in
As shown in
As shown in
As shown in
As shown in
Through the cooling flow passage 50, the cooling water discharged to the outside of the cylinder head 22 via the upper end flow passage port 22c passes through the rectifier/regulator 41, and then passes through the exhaust pipe 25 and a water lock 55 in this order before being discharged to the outside of the hull 10. In the cooling flow passage 50, the cooling water that has flowed into the exhaust pipe 25 is mixed with the exhaust gas that has flowed in through the exhaust flow passage in the exhaust manifold 24. The water lock 55 stores the cooling water mixed with the exhaust gas. The mixture of exhaust gas and cooling water stored in the water lock 55 is discharged to the outside of the hull 10 by the pressure of the exhaust gas.
As shown in
As shown in
As shown in
In the cooling flow passage 50, the cross-sectional area S4 of a flow passage F4 connecting the oil cooler 27 to the cylinder block 23 is smaller than the cross-sectional area S1 of the flow passage F1 connecting the cylinder head 22 to the cylinder block 23. Although
According to the various example embodiments of the present invention described above, the following advantageous effects are achieved.
According to an example embodiment of the present invention, the cooling flow passage 50 is operable to allow cooling water to flow into the cylinder block 23 from the lower side via the lower end flow passage port 23d in the vicinity of or adjacent to the lower end of the flow passage portion 23a in the cylinder block 23. Accordingly, the flow passage connected to the cylinder block 23 via the lower end flow passage port 23d extends downward, and thus water is drained from the flow passage portion 23a in the cylinder block 23 via the lower end flow passage port 23d when the engine 20 is stopped. Consequently, stagnation of cooling water in the flow passage portion 23a provided in the cylinder block 23 is reduced or prevented when the engine 20 is stopped.
According to an example embodiment of the present invention, the cooling flow passage 50 is operable to allow the cooling water that has flowed through the exhaust manifold 24 to flow into the cylinder block 23 via the cylinder head 22. Furthermore, the marine vessel 100 includes the thermostat 54 in the vicinity of or adjacent to the cooling water outlet 23c of the cylinder block 23 to adjust the flow rate of the cooling water discharged from the cylinder block 23 based on the temperature of the cooling water. Accordingly, the cooling water flows into the cylinder block 23 via the cylinder head 22, and thus an excessive decrease in the temperature of the cooling water flowing into the cylinder block 23 is reduced or prevented. Furthermore, the thermostat 54 adjusts the temperature of the cooling water flowing through the flow passage portion 23a provided in the cylinder block 23 to an appropriate temperature. Consequently, excessive cooling of the cylinder block 23 is reduced or prevented.
According to an example embodiment of the present invention, the engine 20 includes the oil cooler 27. The cooling flow passage 50 is operable to allow the cooling water that has flowed through the oil cooler 27 to flow into the cylinder block 23 from the lower side via the lower end flow passage port 23d. Accordingly, the flow passage that allows the cooling water that has cooled the oil cooler 27 to flow into the cylinder block 23 is able to be used as a flow passage that allows water to be drained from the flow passage portion 23a provided in the cylinder block 23 via the lower end flow passage port 23d when the engine 20 is stopped. Consequently, as compared with a case in which a dedicated flow passage is provided to drain water, the structure of the cooling flow passage 50 is simplified.
According to an example embodiment of the present invention, the cooling flow passage 50 is operable to allow the cooling water that has flowed through the cylinder head 22 to be discharged to the outside of the cylinder head 22 via the upper end flow passage port 22c in the vicinity of or adjacent to the upper end of the flow passage portion 22a in the cylinder head 22. Accordingly, the upper end flow passage port 22c is located in the vicinity of or adjacent to the upper end of the flow passage portion 22a provided in the cylinder head 22, and thus air mixed in the cooling water is able to be included to the cooling water discharged from the flow passage portion 22a provided in the cylinder head 22 via the upper end flow passage port 22c. That is, air is bled from the cooling water flowing through the flow passage portion 22a provided in the cylinder head 22 via the upper end flow passage port 22c. Consequently, a decrease in the cooling performance of the cooling water flowing through the cooling flow passage 50 due to air being mixed into the cooling water is reduced or prevented.
According to an example embodiment of the present invention, the marine vessel 100 further includes the rectifier/regulator 41 used to control the engine 20. The cooling flow passage 50 is operable to allow the cooling water discharged to the outside of the cylinder head 22 via the upper end flow passage port 22c to be discharged to the outside of the hull 10 via the rectifier/regulator 41. Accordingly, the flow passage that allows air bleeding from the cooling water flowing through the flow passage portion 22a provided in the cylinder head 22 via the upper end flow passage port 22c is able to be used as a flow passage that allows the cooling water discharged from the flow passage portion 22a provided in the cylinder head 22 to flow into the rectifier/regulator 41 to cool the rectifier/regulator 41. Consequently, as compared with a case in which a dedicated flow passage is provided to bleed air, the structure of the cooling flow passage 50 is simplified.
According to an example embodiment of the present invention, the cooling flow passage 50 is operable to allow a portion of the cooling water that has flowed through the cylinder head 22 to flow into the cylinder block 23, and allow the remaining portion of the cooling water that has flowed through the cylinder head 22 to be discharged to the outside of the cylinder head 22 via the upper end flow passage port 22c. Accordingly, an excessive increase in the number of flow passages for the cooling water discharged from the cylinder head 22 is reduced or prevented, and thus the structure of the cooling flow passage 50 is simplified.
According to an example embodiment of the present invention, the cooling flow passage 50 includes the flow passage F1 connecting the cylinder head 22 to the cylinder block 23 that has the cross-sectional area S1 smaller than the cross-sectional area S2 of the flow passage F2 connecting the exhaust manifold 24 to the cylinder head 22. Accordingly, the cross-sectional area S1 of the flow passage F1 connecting the cylinder head 22 to the cylinder block 23 is relatively small, and thus an excessive increase in the flow rate of the cooling water flowing from the flow passage portion 22a provided in the cylinder head 22 into the flow passage portion 23a provided in the cylinder block 23 is reduced or prevented. Consequently, a structure that reduces or prevents excessive cooling of the cylinder block 23 is easily achieved.
According to an example embodiment of the present invention, the cooling flow passage 50 includes the flow passage F3 (the flow passage connected to the cylinder head 22 via the upper end flow passage port) connecting the cylinder head 22 to the rectifier/regulator 41 that has the cross-sectional area S3 smaller than the cross-sectional area S2 of the flow passage F2 connecting the exhaust manifold 24 to the cylinder head 22. Accordingly, the cross-sectional area S3 of the flow passage F3 connecting the cylinder head 22 to the rectifier/regulator 41 is relatively small, and thus an excessive increase in the flow rate of the cooling water discharged from the cylinder head 22 via the upper end flow passage port 22c is reduced or prevented. Consequently, the possibility is reduced or prevented that the flow rate of the cooling water flowing from the flow passage portion 22a provided in the cylinder head 22 into the flow passage portion 23a provided in the cylinder block 23 is excessively decreased such that the cylinder block 23 is not able to be appropriately cooled.
According to an example embodiment of the present invention, the cooling flow passage 50 includes the flow passage F3 (the flow passage connected to the cylinder head via the upper end flow passage port) connecting the cylinder head 22 to the rectifier/regulator 41 that has the cross-sectional area S3 smaller than the cross-sectional area S1 of the flow passage F1 connecting the cylinder head 22 to the cylinder block 23. Accordingly, an excessive decrease in the cross-sectional area S1 of the flow passage F1 connecting the cylinder head 22 to the cylinder block 23 is reduced or prevented. Consequently, the possibility is reduced or prevented that the flow rate of the cooling water flowing from the flow passage portion 22a provided in the cylinder head 22 into the flow passage portion 23a provided in the cylinder block 23 is excessively decreased such that the cylinder block 23 is not able to be appropriately cooled.
According to an example embodiment of the present invention, the cooling flow passage 50 includes the flow passage F4 (the flow passage connected to the cylinder block via the lower end flow passage port) connecting the oil cooler 27 to the cylinder block 23 that has the cross-sectional area S4 smaller than the cross-sectional area S1 of the flow passage F1 connecting the cylinder head 22 to the cylinder block 23. Accordingly, an excessive decrease in the cross-sectional area S1 of the flow passage F1 connecting the cylinder head 22 to the cylinder block 23 is reduced or prevented. Consequently, the possibility is reduced or prevented that the flow rate of the cooling water flowing from the flow passage portion 22a provided in the cylinder head 22 into the flow passage portion 23a provided in the cylinder block 23 is excessively decreased such that the cylinder block 23 is not able to be appropriately cooled.
According to an example embodiment of the present invention, the cooling flow passage 50 is operable to allow a portion of the cooling water that has flowed in from outside the hull 10 to flow into the exhaust manifold 24, and allow the remaining portion of the cooling water that has flowed in from outside the hull 10 to flow into the oil cooler 27. Accordingly, as compared with a case in which a portion of the cooling water that has flowed in from outside the hull 10 flows into the exhaust manifold 24, another portion of the cooling water that has flowed in from outside the hull 10 flows into the oil cooler 27, and the remaining portion of the cooling water that has flowed in from outside the hull 10 flows into components of the marine vessel 100 other than the exhaust manifold 24 and the oil cooler 27, an excessive decrease in the flow rate of the cooling water flowing into the exhaust manifold 24 is reduced or prevented, and thus the exhaust manifold 24, which becomes relatively hot, is sufficiently cooled.
According to an example embodiment of the present invention, the thermostat 54 is operable to adjust the flow rate of the cooling water discharged from the cylinder block 23 such that the temperature of the cooling water becomes a predetermined temperature of about 50 degrees or more and about 70 degrees or less. Accordingly, the temperature of the cooling water flowing through the flow passage portion 23a provided in the cylinder block 23 is easily adjusted to an appropriate temperature. Consequently, a structure that reduces or prevents excessive cooling of the cylinder block 23 is easily achieved.
According to an example embodiment of the present invention, the cooling flow passage 50 is operable to allow all of the cooling water that has flowed through the exhaust manifold 24 to flow into the cylinder head 22. Accordingly, the flow rate of the cooling water flowing into the cylinder head 22 is relatively increased, and thus the cylinder head 22, which becomes relatively hot, is sufficiently cooled.
According to an example embodiment of the present invention, the marine vessel 100 includes the jet propulsion thruster 30 to generate a thrust using the driving force of the engine 20. Accordingly, in the jet propulsion marine vessel 100, excessive cooling of the cylinder block 23 is reduced or prevented, and stagnation of cooling water in the flow passage portion 23a provided in the cylinder block 23 is reduced or prevented when the engine 20 is stopped.
The example embodiments of the present invention described above are illustrative in all points and not restrictive. The extent of the present invention is not defined by the above description of the example embodiments but by the scope of the claims, and all modifications within the meaning and range equivalent to the scope of the claims are further included.
For example, while the marine vessel 100 preferably includes the jet propulsion thruster 30 to generate a thrust using the driving force of the engine 20 in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the marine vessel may alternatively include a thruster other than the jet propulsion thruster.
While the cooling flow passage 50 preferably allows all of the cooling water that has flowed through the exhaust manifold 24 to flow into the cylinder head 22 in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the cooling flow passage may alternatively allow only a portion of the cooling water that has flowed through the exhaust manifold to flow into the cylinder head.
While the thermostat 54 preferably adjusts the flow rate of the cooling water discharged from the cylinder block 23 such that the temperature of the cooling water becomes a predetermined temperature of about 50 degrees or more and about 70 degrees or less in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the thermostat may alternatively adjust the flow rate of the cooling water discharged from the cylinder block such that the temperature of the cooling water becomes a predetermined temperature that is less than about 50 degrees or more than about 70 degrees.
While the cooling flow passage 50 preferably allows a portion of the cooling water that has flowed in from outside the hull 10 to flow into the exhaust manifold 24 and allows the remaining portion of the cooling water that has flowed in from outside the hull 10 to flow into the oil cooler 27 in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the cooling flow passage may alternatively allow a portion of the cooling water that has flowed in from outside the hull to flow into the exhaust manifold, allow another portion of the cooling water that has flowed in from outside the hull to flow into the oil cooler, and allow the remaining portion of the cooling water that has flowed in from outside the hull to flow into components of the marine vessel other than the exhaust manifold and the oil cooler.
While the cooling flow passage 50 preferably includes the flow passage F4 (the flow passage connected to the cylinder block via the lower end flow passage port) connecting the oil cooler 27 to the cylinder block 23 that has the cross-sectional area S4 smaller than the cross-sectional area S1 of the flow passage F1 connecting the cylinder head 22 to the cylinder block 23 in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the cooling flow passage may alternatively include the flow passage connected to the cylinder block via the lower end flow passage port that has a cross-sectional area equal to or larger than the cross-sectional area of the flow passage connecting the cylinder head to the cylinder block.
While the cooling flow passage 50 preferably includes the flow passage F3 (the flow passage connected to the cylinder head via the upper end flow passage port) connecting the cylinder head 22 to the rectifier/regulator 41 that has the cross-sectional area S3 smaller than the cross-sectional area S1 of the flow passage F1 connecting the cylinder head 22 to the cylinder block 23 in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the cooling flow passage may alternatively include the flow passage connected to the cylinder head via the upper end flow passage port that has a cross-sectional area equal to or larger than the cross-sectional area of the flow passage connecting the cylinder head to the cylinder block.
While the cooling flow passage 50 preferably includes the flow passage F3 (the flow passage connected to the cylinder head via the upper end flow passage port) connecting the cylinder head 22 to the rectifier/regulator 41 that has the cross-sectional area S3 smaller than the cross-sectional area S2 of the flow passage F2 connecting the exhaust manifold 24 to the cylinder head 22 in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the cooling flow passage may alternatively include the flow passage connected to the cylinder head via the upper end flow passage port that has a cross-sectional area equal to or larger than the cross-sectional area of the flow passage connecting the exhaust manifold to the cylinder head.
While the cooling flow passage 50 preferably includes the flow passage F1 connecting the cylinder head 22 to the cylinder block 23 that has the cross-sectional area S1 smaller than the cross-sectional area S2 of the flow passage F2 connecting the exhaust manifold 24 to the cylinder head 22 in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the cooling flow passage may alternatively include the flow passage connecting the cylinder head to the cylinder block that has a cross-sectional area equal to or larger than the cross-sectional area of the flow passage connecting the exhaust manifold to the cylinder head.
While the cooling flow passage 50 preferably allows a portion of the cooling water that has flowed through the cylinder head 22 to flow into the cylinder block 23 and allows the remaining portion of the cooling water that has flowed through the cylinder head 22 to be discharged to the outside of the cylinder head 22 via the upper end flow passage port 22c in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the cooling flow passage may alternatively allow a portion of the cooling water that has flowed through the cylinder head to flow into the cylinder block, allow another portion of the cooling water that has flowed through the cylinder head to be discharged to the outside of the cylinder head via the upper end flow passage port, and allow the remaining portion of the cooling water that has flowed through the cylinder head to flow into components of the marine vessel other than the cylinder block and the flow passage connected to the cylinder block via the upper end flow passage port.
While the cooling flow passage 50 preferably allows the cooling water discharged to the outside of the cylinder head 22 via the upper end flow passage port 22c to be discharged to the outside of the hull 10 via the rectifier/regulator 41 in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the cooling flow passage may alternatively allow the cooling water discharged to the outside of the cylinder head via the upper end flow passage port to be discharged to the outside of the hull without passing through the rectifier/regulator.
While the cooling flow passage 50 preferably allows the cooling water that has flowed through the cylinder head 22 to be discharged to the outside of the cylinder head 22 via the upper end flow passage port 22c provided in the vicinity of or adjacent to the upper end of the flow passage portion 22a provided in the cylinder head 22 in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the cooling flow passage may not allow the cooling water that has flowed through the cylinder head to be discharged to the outside of the cylinder head via the upper end flow passage port.
While the cooling flow passage 50 preferably allows the cooling water that has flowed through the oil cooler 27 to flow into the cylinder block 23 from the lower side via the lower end flow passage port 23d in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the cooling flow passage may alternatively allow the cooling water that has not flowed through the oil cooler 27 to flow into the cylinder block from the lower side via the lower end flow passage port.
While the marine vessel 100 is preferably a water jet propulsion boat (wet bike) in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the marine vessel may alternatively be a pleasure boat, for example.
While example embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-202261 | Nov 2023 | JP | national |
