PROPULSION UNIT FOR A MARINE VESSEL

Abstract

A propulsion unit for a marine vessel is adapted to receive power from at least one power supply unit. The propulsion unit includes a stationary part adapted to be mounted to a hull of the marine vessel, and a movable part comprising one or more thrust generating devices adapted to transform the received power into a thrust by acting on water carrying the marine vessel. The propulsion unit is adapted to receive exhaust gases from at least two internal combustion engines, wherein the movable part is adapted to release the exhaust gases into the water.

Claims

1. A propulsion unit for a marine vessel, adapted to receive power from at least one power supply unit, wherein the propulsion unit comprises a stationary part adapted to be mounted to a hull of the marine vessel, and a movable part comprising one or more thrust generating devices adapted to transform the received power into a thrust by acting on water carrying the marine vessel, wherein the propulsion unit is adapted to receive exhaust gases from at least two internal combustion engines, wherein the movable part is adapted to release the exhaust gases into the water.

2. A propulsion unit according to claim 1, wherein the propulsion unit comprises two unit inlets each adapted to receive exhaust gases from a respective of two engines.

3. A propulsion unit according to claim 2, wherein the movable part comprises at least one unit outlet for releasing the exhaust gases into the water, and the propulsion unit is adapted to keep the exhaust gases separate along at least a part of the distance between the unit inlets and the unit outlet.

4. A propulsion unit according to claim 2, wherein the stationary part comprises two stationary exhaust conduits each extending from a respective of the unit inlets to the movable part.

5. A propulsion unit according to claim 4, wherein the stationary part comprises two stationary outlets adapted to deliver the exhaust gases to the movable part.

6. A propulsion unit according to claim 5, wherein the movable part comprises two movable inlets each adapted to receive exhaust gases from a respective of the stationary outlets.

7. A propulsion unit according to claim 5, wherein the movable part is rotatable in relation to the stationary part around a rotation axis for adjusting the direction of the thrust in relation to the hull, wherein the movable part comprises at least one movable inlet adapted to receive exhaust gases from the stationary outlets, wherein the extension, in a circumferential direction in relation to the rotational axis, of the movable inlet is larger than the extension, in the circumferential direction, of the stationary outlets.

8. A propulsion unit according to claim 4, wherein the movable part is rotatable in relation to the stationary part around a rotation axis for adjusting the direction of the thrust in relation to the hull, wherein the unit inlets are located at separate positions in a circumferential direction in relation to the rotation axis, wherein the stationary outlets are located at separate positions in a radial direction in relation to the rotation axis, wherein a stationary wall separating the stationary exhaust conduits is twisted along the stationary exhaust conduits.

9. A propulsion unit according to claim 4, wherein the movable part is rotatable in relation to the stationary part around a rotation axis for adjusting the direction of the thrust in relation to the hull, wherein the stationary part comprises a stationary wall separating the stationary exhaust conduits, wherein the distance, at the movable part, from the rotation axis to the stationary wall is constant along the stationary wall.

10. A propulsion unit according to claim 9, wherein the movable part comprises two movable exhaust conduits, wherein the movable part comprises a movable wall separating the movable exhaust conduits, wherein the movable wall coincides, at the stationary part, as seen along the rotation axis, with the stationary wall.

11. A propulsion unit according to claim 10, wherein the propulsion unit comprises a seal at an interface between the stationary part and the movable part, the seal being adapted to seal exhaust gases guided by one of the stationary exhaust conduits, and by one of the movable exhaust conduits, from exhaust gases guided by the other of the stationary exhaust conduits, and by the other of the movable exhaust conduits.

12. A propulsion unit according to claim 4, wherein the movable part comprises two movable exhaust conduits, each adapted to receive exhaust gases from a respective of the stationary exhaust conduits, wherein the movable exhaust conduits terminate at a respective of two unit outlets for releasing the exhaust gases into the water.

13. A propulsion unit according to claim 12, wherein the movable part is rotatable in relation to the stationary part around a rotation axis for adjusting the direction of the thrust in relation to the hull, and the two unit outlets are arranged to be distributed substantially transversally in relation to the movable part rotation axis.

14. A propulsion unit according to claim 12, wherein the movable part comprises a movable wall separating the movable exhaust conduits, wherein the unit outlets are formed at least partly by the movable wall, wherein at least a lower part of the movable wall is removable.

15. A propulsion system comprising a propulsion unit according to claim 1, and two internal combustion engines, the engines both being arranged to deliver power to the propulsion unit.

16. A marine vessel with a propulsion system according to claim 15.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] With reference to the appended drawings, below follows a more detailed description of embodiments of the invention cited as examples. In the drawings:

[0043] FIG. 1 is a perspective view from below of a marine vessel comprising a propulsion system comprising a propulsion unit according an embodiment of the invention.

[0044] FIG. 2 is a side view of the propulsion system of the marine vessel in FIG. 1.

[0045] FIG. 3 is a cross-sectional view of the propulsion unit of the marine vessel in FIG. 1, the section coinciding with propeller axes and driveshafts of the propulsion unit.

[0046] FIG. 4 is a cross-sectional view of the propulsion unit with the section oriented as indicated by the arrows IV-IV in FIG. 3.

[0047] FIG. 5 is a cross-sectional view of the propulsion unit with the section oriented as indicated by the arrows V-V in FIG. 3.

[0048] FIG. 6 and FIG. 7 are cross-sectional views of the propulsion unit, with the sections oriented as indicated by the arrows V-V in FIG. 3, where a movable part of the propulsion unit is rotated in relation to a stationary part of the propulsion unit.

[0049] FIG. 8 is a cross-sectional view, similar to the view in FIG. 3, of a propulsion unit according to an alternative embodiment of the invention.

[0050] FIG. 9 is a cross-sectional view, similar to the view in FIG. 3, of a propulsion unit according to a further embodiment of the invention.

[0051] FIG. 10 is a view of a part of the propulsion unit in FIG. 9, from behind as indicated with the arrow X in FIG. 9.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

[0052] FIG. 1 shows a marine vessel 1 in the form of a power boat. It should be noted that the invention is equally applicable to other types of marine vessels, such as ships or sailing yachts. The marine vessel 1 comprises a hull 2 having a bow 3 and a stern 4. The marine vessel 1 further comprises a propulsion system with a propulsion unit 200 according to an embodiment of the invention. In this example, the propulsion unit is a pod drive.

[0053] Reference is made also to FIG. 2. The propulsion unit 200 comprises a stationary part 215 adapted to be mounted to the hull of the marine vessel. The stationary part comprises an intermediate housing 2153. The intermediate housing is adapted to be mounted to the hull, in a cutout of the hull. The cutout is below the waterline of the hull. Sealing rings 2154 are provided to seal between the intermediate housing and the hull.

[0054] The propulsion unit also comprises a movable part 220. The movable part is adapted to be immerged in water carrying the marine vessel. The propulsion system comprises two internal combustion engines 210a, 210b. In this embodiment, the engines form respective power supply units, adapted to deliver mechanical power to the propulsion unit 200. In this embodiment, the engines are, in relation to a direction of straight forward travel of the marine vessel, located forward and behind the propulsion unit 200.

[0055] The movable part comprises two thrust generating devices in the form of propellers 230, adapted to transform the received power into a thrust by acting on the water carrying the marine vessel. The propellers are coaxially arranged, and counter-rotating. However, the invention is equally applicable to propulsion units with a single propeller. The propellers are in this embodiment pulling propellers. However, the invention is equally applicable to propulsion units with one or more pushing propellers. It should be also be noted that the invention is equally applicable to other types of propulsion units, such as stern drives.

[0056] Reference is made also to FIG. 3. The movable part 220 is rotatable in relation to the stationary part 215 around a rotation axis R for adjusting the direction of the thrust in relation to the hull. For this, the propulsion unit comprises a rotation bearing arrangement 2001. The movable part is arranged to be rotated by means of one or more rotation actuators, e.g. in the form of one or more electrical motors 2002 and a cog engagement. The one or more rotation actuators may be controllable by an electronic control unit (not shown) in dependence on signals from a user maneuvering device such as a steering wheel (not shown). The control unit may comprise computing means such as a CPU or other processing device, and storing means such as a semiconductor storage section, e.g., a RAM or a ROM, or such a storage device as a hard disk or a flash memory.

[0057] The stationary part 215 comprises an input transmission 2151 for transferring power from respective power supply unit output shafts 210a1, 210b1, to an intermediate drive shaft 2152 of the power unit. The power supply units 210a, 210b may be disengageably connectable to the input transmission, e.g. by means of respective disc clutches, such as e.g. dry or wet plate clutches, centrifugal clutches, overrunning clutches, and/or electromagnetic clutches. The input transmission 2151 may be provided as described in WO2020083494A1, incorporated herein by reference. Such a transmission has two output gears and two clutches for reversing the rotational direction of the intermediate drive shaft 2152. However, it should be noted that the input transmission may be provided in any suitable way. For example, reversing gears may be provided between the engines and the propulsion unit. Thereby, the input transmission may be provided with a single output gear, and no clutch.

[0058] In use, the intermediate drive shaft 2152 may be substantially perpendicular to a local extension of the hull where the propulsion unit is installed. The intermediate drive shaft 2152 extends from the stationary part 215 to into the movable part 220. The intermediate drive shaft 2152 is coaxial with the rotation axis R. The movable part 220 comprises an output transmission 2201 arranged to transfer power from the intermediate drive shaft 2152 to two final drive shafts 2301, 2302, each arranged to transfer respective portions of the power to a respective of the thrust generating devices 230. The intermediate shaft preferably comprises two shaft parts, connected with a spline sleeve (not shown).

[0059] The propulsion unit is adapted to receive exhaust gases from the engines 210a, 210b, and the movable part 220 is adapted to release the exhaust gases into the water.

[0060] Reference is made also to FIG. 4. For receiving the exhaust gases from the engines, the propulsion unit comprises two unit inlets 301, 302. Each unit inlet 301, 302 is adapted to receive exhaust gases from a respective of the engines 210a, 210b. The delivery of the exhaust gases from the engines, e.g. from exhaust treatment devices thereof, may be done by respective exhaust pipes 210a2, 210b2, (FIG. 2).

[0061] As exemplified in FIG. 3, the stationary part 215 comprises two stationary exhaust conduits 305, 306 each extending from a respective of the unit inlets 301, 302 to the movable part 220.

[0062] The stationary part 215 further comprises two stationary outlets 307, 308 adapted to deliver the exhaust gases to the movable part 220. The movable part 220 comprises two movable inlets 313, 314 each adapted to receive exhaust gases from a respective of the stationary outlets 307, 308.

[0063] As can be seen in FIG. 4, the unit inlets 301, 302 are located at separate positions in a circumferential direction in relation to the rotation axis R. As can be seen in FIG. 3, the stationary outlets 307, 308 are located at separate positions in a radial direction in relation to the rotation axis R. For this, a stationary wall 309 separating the stationary exhaust conduits 305, 306 is twisted along the stationary exhaust conduits.

[0064] Reference is made also to FIG. 5-FIG. 7. The distance, at the movable part 220, from the rotation axis R to the stationary wall 309 is constant along the stationary wall, (shown in FIG. 7). For this, the stationary wall 309 is at the movable part curved, with a curvature of an imaginary circle passing through the stationary wall 309 and with a center at the rotation axis R.

[0065] As can be seen in FIG. 3, the movable part 220 comprises two movable exhaust conduits 315, 316. The movable part comprises a movable wall 317 separating the movable exhaust conduits. As understood from FIG. 5-FIG. 7, the movable wall 317 coincides, at the stationary part 215, as seen along the rotation axis R, with the stationary wall 309. For this, the movable wall 317 is at the stationary part 215 curved, with a curvature which is substantially the same as that of the stationary wall 309 at the movable part 220. Thus, in any rotational position of the movable part 220, the movable wall 317 overlaps, in a radial direction, the stationary wall 309.

[0066] As can be seen in FIG. 3, the propulsion unit comprises a seal 321 at the interface between the stationary part 215 and the movable part 220. In this embodiment, the seal is fixed to the stationary part 215. The seal is adapted to seal exhaust gases guided by one of the stationary exhaust conduits 305, 306, and by one of the movable exhaust conduits, from exhaust gases guided by the other of the stationary exhaust conduits, and by the other of the movable exhaust conduits.

[0067] The movable part 220 comprises a unit outlet 311 for releasing the exhaust gases into the water. The unit outlet 311 is formed at a rear end of a substantially cylindrically shaped access space 2202 for reaching the propeller drive assembly of the movable part, e.g. for service or repair. The movable wall 317 terminates between the movable inlets 313, 314 and the unit outlet 311. Thus, the propulsion unit is adapted to keep the exhaust gases separate along the distance between the unit inlets 301, 302 and where the movable wall 317 terminates.

[0068] As can be seen in FIG. 5-FIG. 7, the extension, in a circumferential direction in relation to the rotational axis R, of the movable inlets 313, 314 is larger than the extension, in the circumferential direction, of the stationary outlets 307, 308. Thereby, the movable part 220 may be rotated while the movable inlets 313, 314 remain fully overlapping the stationary outlets 307, 308. In this example, this full overlap is provided up to a rotation angle of the movable part 220, in relation to a neutral position of the movable part for steering the vessel straight ahead, of about 7 degrees, as illustrated in FIG. 6.

[0069] The movable inlets 313, 314 extend in the circumferential direction all the way to delimiting walls of the movable part. As the rotation angle of the movable part 220 increases, the movable part is moved so as to expose the stationary outlets 307, 308 directly to the surrounding water, as illustrated by FIG. 7.

[0070] Reference is made to FIG. 8, showing an alternative embodiment of the invention. The embodiment is similar to the one described with reference to FIG. 1-FIG. 7, except for the following. There is no movable wall 317. Instead, the movable part comprises a single movable inlet 313 adapted to receive exhaust gases from both stationary outlets 307, 308. Thus, the propulsion unit is adapted to keep the exhaust gases separate along the distance between the unit inlets 301, 302 and the stationary outlets 307, 308.

[0071] Reference is made to FIG. 9 and FIG. 10, showing a further embodiment of the invention. As the embodiment described with reference to FIG. 1-7, the propulsion unit comprises a movable wall 317. The movable part 220 comprises two unit outlets 311, 312 for releasing the exhaust gases into the water. The unit outlets 311, 312 are formed partly by the movable wall 317. Thus, the propulsion unit is adapted to keep the exhaust gases separate along the distance between the unit inlets 301, 302 and the unit outlets 311, 312.

[0072] A lower part 3171 of the movable wall 317 is twisted. At the unit outlets 311, 312, the movable wall 317 extends substantially in parallel with the movable part rotational axis. Thereby, as understood from FIG. 10, the unit outlets 311, 312 are distributed substantially transversally in relation to the movable part rotation axis. Thereby, the vertical overlap of the unit outlets is eliminated, or kept small. Thereby, when the vessel is not moving, and only one of the engines is operating, the risk of exhaust gases from the operating engine entering the exhaust path of the non-operating engine, is eliminated. More specifically, in such a situation, the exhaust gases exiting any of the outlets will rise in the surround water, without passing the other of the unit outlets 311, 312.

[0073] The lower part 3171 of the movable wall 317 is removable. Thereby, access can be provided to the access space 2202 for reaching the propeller drive assembly. It should be noted however, that in some embodiments, the entire movable wall is fixed to the remainder of the movable part 220. In such embodiments, the movable part may be arranged so that access to the propeller drive assembly can be provided from where the propellers are located.

[0074] It should be noted that where the propulsion unit has one or more pushing propellers, one or more unit outlets may be provided in a propeller hub. Thereby, the exhaust gases may be guided through one or more of the one or more propellers.

[0075] It is to be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.

[0076] For example, one or more auxiliary exhaust conduit may be provided, to guide exhaust gases from the engines to one or more auxiliary exhaust outlets. The one or more auxiliary exhaust outlets may be located in the vessel hull, e.g. above the waterline. The one or more auxiliary exhaust conduits may be used when the vessel is not moving, or moving slowly, and the engines are idling, or are running at a rotational speed slightly above idling.