Propulsion system with integrated motor and disconnect clutch and method

Abstract

A propulsion system (12) includes an engine (14) having an engine output shaft (16); and a motor assembly (18) including a motor (20) having an output gear (28) fixed to rotate with the drive shaft (26); and a disconnect clutch (30). The motor assembly further includes a common housing (32) positioned around the motor and the disconnect clutch, and a fluid system (40) including a fluid circuit (42) for cooling and lubricating the motor and the disconnect clutch. Related methods including operating the propulsion system in a motor-only mode, an engine-only mode, and a hybrid mode are also disclosed.

Description

Technical Field

[0001] The present invention generally relates to a propulsion system, and more specifically to an electric motor assembly comprising a common housing positioned around the electric motor and a hydraulically actuated disengagement clutch. Background Technology

[0002] Many different propulsion system configurations are known for use in mobile machinery, including land vehicles and ships. For decades, propulsion systems have typically been based on internal combustion engines, including diesel and / or natural gas engines, gasoline engines, and even gas turbine engines. Electric propulsion systems have also been widely adopted for many years. More recently, various hybrid propulsion systems employing both internal combustion engines and electricity have achieved considerable commercial success.

[0003] Current market offerings of hybrid propulsion systems, particularly in marine propulsion, often require end-users to integrate multiple disparate systems from different suppliers. Consequently, end-users typically need to identify, procure, and assemble different aspects of the machine, and purchase or even customize parts. For example, individual components of the propulsion system often require their own auxiliary systems, such as fluid supply, cooling systems, and computer control units. In addition to the integration challenges, installing a hybrid propulsion system pieced together from different suppliers inevitably requires more space than ideal. A known hybrid propulsion system is described in U.S. Patent No. 6,986,727 to Kuras et al. The art offers ample opportunities for improvement and development of alternative strategies. Summary of the Invention

[0004] In one aspect, a propulsion system includes an engine having an engine output shaft; and an electric motor assembly having an electric motor including a rotor and a stator, a drive shaft, an output gear fixed and rotating with the drive shaft, and a hydraulically actuated release clutch. The release clutch is operatively positioned between the drive shaft and the engine output shaft. The electric motor assembly further includes a common housing having a plurality of attached housing components positioned together around the electric motor and the release clutch, and a fluid system including a fluid circuit for cooling and lubricating at least one of the electric motor or the release clutch.

[0005] In another aspect, an electric motor assembly includes an electric motor having a rotor and a stator, a drive shaft, and an output gear fixed and rotating with the drive shaft. The electric motor assembly further includes a disengagement clutch coupled to the drive shaft and configured to be coupled to an engine output shaft, and the disengagement clutch is adjustable from a disengaged state to an engaged state to engage the drive shaft to the engine output shaft. The electric motor assembly further includes a common housing having a clutch housing component positioned around the disengagement clutch, a gear train housing component positioned around the output gear, and an electric motor housing component positioned around the electric motor and attached between the gear train housing component and the clutch housing component.

[0006] In another aspect, a method of operating a propulsion system includes: in an electric motor-only mode of the propulsion system, applying torque to a drive shaft via a rotor rotatably coupled to a drive shaft through stator coils in an energized electric motor. The method further includes: engaging a disengagement clutch positioned in a common housing with the electric motor to connect the drive shaft to an engine output shaft; and, in an engine-only mode of the propulsion system, applying torque to the drive shaft via the engine output shaft when the disengagement clutch is engaged and the stator coils are de-energized. The method further includes, in a hybrid mode of the propulsion system, applying torque to the drive shaft via stator coils energized when the disengagement clutch is engaged, and, in each of the electric motor-only, engine-only, and hybrid modes, operating a final drive unit in the machine via the torque applied to the drive shaft. Attached Figure Description

[0007] Figure 1 This is a schematic view of a machine having a propulsion system according to one embodiment;

[0008] Figure 2 This is a schematic diagram of a propulsion system according to one embodiment;

[0009] Figure 3 This is a schematic view of an electric motor assembly for a propulsion system according to one embodiment;

[0010] Figure 4 This is another schematic view of the motor assembly;

[0011] Figure 5 This is another illustrated view of the electric motor assembly;

[0012] Figure 6 This is another illustrated view of the electric motor assembly;

[0013] Figure 7 This is another illustrated view of the electric motor assembly;

[0014] Figure 8This is a schematic view of a valve block according to one embodiment;

[0015] Figure 9 This is another schematic view of the valve block; and

[0016] Figure 10 This is a cross-sectional side view of an electric motor assembly according to one embodiment; Detailed Implementation

[0017] See Figure 1 The image illustrates a machine 8 according to one embodiment, which includes a frame 10 and a propulsion system 12 supported on the frame 10. In some embodiments, the machine 8 includes a vessel, such that the frame 10 forms or supports the vessel's deck or hull. The propulsion system 12 includes an internal combustion engine 14 having an engine output shaft 16. The engine 14 may include a direct-injection compression ignition diesel engine having multiple combustion cylinders. In other implementations, different engine configurations and operating and / or fuel supply and ignition strategies may be employed.

[0018] The propulsion system 12 may further include an electric motor assembly 18 having an electric motor 20, a hydraulically actuated disengagement clutch 30, and a takeoff gear train 54. The electric motor assembly 18 further includes a fluid system 40. The electric motor assembly 18 may be coupled to a drive coupling 46, which rotates the final drive unit 50. Operating the final drive unit 50 via the drive coupling 46 and gearbox 48 may include, in marine applications, coupling the final drive unit 50 to a propeller 53. In other applications, for example, the final drive unit 50 may be coupled to one or more ground-engaged wheels or tracks. As will become clear from the following description, the invention contemplates operating the propulsion system 18 in a variety of different modes, including an electric motor-only mode, an engine-only mode, and a hybrid mode. The fluid system 40 may be configured to provide cooling and lubrication to the electric motor assembly 18, including to the electric motor 20, and to the disengagement clutch 30 in each of the engine-only mode, electric motor-only mode, and hybrid mode, the characteristics and significance of which will become clear from the following description.

[0019] See also Figure 2The electric motor 20 includes a rotor 22, a stator 24, a drive shaft 26, and an output gear 28 fixed and rotating together with the drive shaft 26. A disengagement clutch 30 is operatively positioned between the drive shaft 26 and the engine output shaft 16. The disengagement clutch 30 is adjustable from a disengaged state to an engaged state to connect the drive shaft 26 to the engine output shaft 16 by changing the pressure of the clutch actuating fluid. The electric motor assembly 18 may further include a common housing 32 having a plurality of attached housing components 34, 36, 38, which together are positioned around the electric motor 20, the takeoff gear train 54, and the disengagement clutch 30.

[0020] In one embodiment, the common housing 32 includes a clutch housing component 38 positioned around the disengagement clutch 30, a gear train housing component 34 positioned around the output gear 28, and a motor housing component 36 attached between the gear train housing component 34 and the clutch housing component 38. The output gear 28 can be coupled to a takeoff gear train 54, which is at least partially positioned in the common housing 32, and specifically at least partially positioned in the gear train housing component 34.

[0021] The fluid system 40 may further include a fluid circuit 42 for cooling and lubricating at least one of the electric motor 20 or the disengagement clutch 30. The fluid system 40 may also include a cooling and lubrication pump or a first pump 52, which rotates via the takeoff gear train 54 and is mounted on the common housing 32. The fluid system 40 may also include a clutch actuation pump or a second pump 58, which rotates via the engine gear train 56 of the engine 14. The first pump 52 may include a low-pressure cooling and lubrication pump mounted on the electric motor assembly 18. The second pump 58 may include a high-pressure clutch actuation pump mounted external to the electric motor assembly 18, such as mounted to the engine housing or other support structure associated with or adjacent to the engine 14.

[0022] The common housing 32 may further have at least one cooling and lubricating fluid supply port formed therein, including a first cooling and lubricating fluid supply port 70 and a second cooling and lubricating fluid supply port 71 in the illustrated embodiment. The common housing 32 may further include a first cooling and lubricating fluid discharge 72 and a second cooling and lubricating fluid discharge 73 formed therein. In the illustrated embodiment, the first cooling and lubricating fluid supply port 70 is formed in the clutch housing component 38 and the second cooling and lubricating fluid supply port 71 is formed in the gear housing component 34. Therefore, cooling and lubricating fluid (such as oil) can be supplied from each of the clutch housing component 38 and the gear housing component 34 to the motor housing component 36. The first cooling and lubricating fluid discharge 72 and the second cooling and lubricating fluid discharge 73 may be formed in the gear housing component 34 and the clutch housing component 38, respectively. Therefore, cooling and lubricating fluid can be discharged from the motor housing component 36 to the gear housing component 34 and the clutch housing component 38. The common housing 32 may further include a clutch actuation fluid supply port 74 and a clutch actuation fluid discharge 76 formed therein. The clutch actuation fluid and the cooling and lubrication fluid can be the same fluid, wherein the fluid system 20 is configured such that the fluid can flow to the first pump 52 and the second pump 58 respectively, and that the combined flow of the fluid is returned for recirculation. The fluid system 40 may further include a common fluid reservoir 78 mounted on a common housing 32, which receives the combined flow of the discharged fluid used in cooling and lubrication and clutch actuation.

[0023] As described above, the fluid system 40 may include a fluid circuit 42. The fluid system 40 may also include a clutch-actuated fluid circuit 60. The cooling and lubrication circuit 42 is fluidly connected to a first pump 52, such that the first pump 52 is arranged in the cooling and lubrication circuit 42, and the clutch-actuated fluid circuit 60 is fluidly connected to a second pump 58, such that the second pump 58 is arranged in the actuation fluid circuit 60. The fluid system 40 may also include, for example, an interconnect 102 formed in a valve block 100 mounted on a common housing 32, which fluidly connects the cooling and lubrication fluid circuit 42 to the clutch-actuated fluid circuit 60.

[0024] The fluid system 40 may further include a cooler 80, which is arranged to receive the outflow of fluid from the first pump 52, which is supplied to the common housing 32 via a pump outflow conduit 62. A coolant conduit 81 may carry coolant for cooling the fluid delivered via the pump outflow conduit 62. The fluid system 40 may also include a filter 82 that filters the fluid already cooled in the cooler 80. Pressure sensors 90 and temperature sensors 92 may be located on or within the valve block 100 to monitor the pressure and temperature of the fluid delivered through the cooling and lubrication circuit 42. The pump supply conduit 64 includes a suction conduit and delivers fluid from the common fluid reservoir 78 to the first pump 52. Another pump outflow conduit 66 receives fluid pumped by the second pump 58, which is supplied to the common housing 32 and typically delivered to the valve block 100 via a clutch-actuated fluid circuit 60 through another filter 84. Pump supply line 68 includes a suction line for conveying fluid from common fluid reservoir 78 to second pump 58. Cooling and lubrication fluid circuit 42 may be fluidly connected to clutch actuation fluid circuit 60 via at least one of respective pump outlet lines 62 and 66 or respective pump supply lines 64 and 68. In the illustrated embodiment, pump outlet lines 62 and 66 are fluidly connected to circuits 42 and 60 via interconnect 102 in valve block 100, while pump supply lines 64 and 68 are fluidly connected to circuits 42 and 60 via common fluid reservoir 78. A clutch control valve, such as a so-called ICTG valve, is shown at 88, which can be electrically actuated to change the pressure of the clutch actuation fluid supplied to clutch 30, causing the clutch to engage and disengage.

[0025] See also Figure 3 and Figure 4 Further features and details of an example embodiment of the electric motor assembly 18 are shown. Figure 3 As shown, the common housing 32 can be attached to a first mounting rod 104 and a second mounting rod 104, which are attached to a first side and a second side of the common housing 32, respectively. The mounting rods 104 can be used to position and support the motor assembly 18 on a machine (such as a ship, as discussed herein). Figure 3 In the middle, the second pump 58 is shown, which may be located outside the common housing 32 to be positioned near the engine 14 and connected to the engine gear train 56. Figure 4 A first pump 52 is shown mounted on a common housing 32. In the illustrated embodiment, a mounting rod 104 is attached to a gear train housing component 34, and the first pump 52 is also mounted to the gear train housing component 34. Other embodiments may include different arrangements.

[0026] like Figure 3The image also depicts a common fluid reservoir 78 mounted on the gear housing component 34 via a reservoir mounting surface 96. Figure 3 Also shown is a downwardly suspended fluid collection portion 94 of the gear housing component 34, which is positioned to receive cooling and lubricating fluid discharged under gravity through the common housing 32. A reservoir mounting surface 96 is at least partially formed on the fluid collection portion 94. It can be seen that each of the pump supply lines 64 and 68 is fluidly connected to the common fluid reservoir 78. The common fluid reservoir 78 may be equipped with an internal screen filter or the like for filtering fluid in the cooling and lubricating fluid circuit 42 and the clutch actuation fluid circuit 60. Figure 3 and Figure 4 Pump outlet pipes 62 and 66 are also shown, which are arranged to provide pumped fluid from the respective pumps to a common housing 32, as discussed further herein.

[0027] See also Figure 5 , Figure 6 and Figure 7 Further details of the motor assembly 18 can be seen here. Figure 5 As shown, the clutch housing component 38 may have a valve block mounting surface 106 formed thereon. Cooling and lubricating fluid supply ports 70 and clutch actuation fluid supply ports 74 are shown as formed in the valve block mounting surface 106. A pump mounting surface 96 is formed on the gear train housing component 34. The takeoff gear train 54 is visible as being surrounded by the pump mounting surface 96.

[0028] like Figure 6 As shown, the motor housing component 36 may include a first end flange 110 bolted to the gear housing component 34 and a second end flange 112 bolted to the clutch housing component 38. The motor housing component 36 may also include a cylindrical central portion 108 extending from the first end flange 110 to the second end flange 112. In view of this specification and the accompanying drawings, it should be understood that components of the secondary system may be primarily or entirely mounted on the gear housing component 34 or the clutch housing component 38. This strategy allows for the selection of the motor housing component 36 from a range of different motor housing components depending on the application, and its use with the same clutch housing component 38 and gear housing component 34. By selecting a suitable motor housing component 36, various modifications to the motor assembly 18 can be adapted in this way. For example, a relatively large motor can be positioned in a relatively large motor housing component, while a relatively small motor can be arranged in a relatively small motor housing component. In this way, variations in the internal geometry, dimensions, etc., of the motor can be accommodated by a variable-sized motor housing attached between the same clutch and gear housing components.

[0029] Now focus on Figure 7 Two externally mounted fluid conduits 114 and 116 are visible, which transport fluid from gear housing component 34 to clutch housing component 38. Fluid conduit 116 can supply cooling and lubricating fluid directly from gear housing component 34 to clutch housing component 38, and fluid conduit 114 can supply cooling and lubricating fluid directly from gear housing component 34 to valve block 100. Fluid conduit 114 is fluidly connected between the first pump 52 and valve block 100. Cooling and lubricating fluid pumped in the cooling and lubrication circuit 42 by the first pump 52 can be delivered to gear housing component 34 and then delivered through or via the external conduits 114 and 116 to clutch housing component 38 through motor housing component 36. As discussed above, cooling and lubricating fluid can be supplied from the corresponding gear housing component 34 and clutch housing component 38 to motor housing component 36. It should be noted that motor housing component 36 can have a range of sizes depending on the application. Therefore, pipes 114 and 116 can also have variable dimensions, with longer pipes for longer motor housings and shorter pipes for shorter motor housings. By attaching one or more pipes 114, 116 externally to the gear housing component 34 and the clutch housing component 38, variable or selectable dimensions of the motor housing component 36 can be achieved without establishing internal fluid connections for supplying cooling and lubricating fluids. In this embodiment, cooling and lubricating fluids are supplied from the gear housing component 34 to the clutch housing component 38. In other embodiments, a reverse fluid flow pattern can be used to supply fluid from the clutch housing component 38 to the gear housing component 34. Bidirectional flow of cooling and lubricating fluids between the gear housing component 34 and the clutch housing component 38 is also within the scope of this invention.

[0030] See also Figure 8 and Figure 9 The diagram shows different views of the valve block 100. The valve block 100 includes a block body 128 having a contact surface 132 configured to be positioned against a valve block mounting surface 106. Threaded bolt holes 130 extend through the block body 128 for bolting the valve block 100 to the clutch housing assembly 38. A sealing groove 121 is formed in the contact surface 132 to receive a seal, thereby fluidly sealing around the high-pressure outlet 120 for delivering clutch actuating fluid to port 74 and the low-pressure outlet 124 for delivering cooling and lubricating fluid to port 70.

[0031] It should be remembered that interconnect 102 fluidly connects the cooling and lubrication fluid circuit 42 to the clutch actuation fluid circuit 60. Interconnect 102 may be formed within the valve block 100; however, it should be understood that other locations for interconnecting the respective fluid circuits are contemplated, such as within the common housing 32 or even between external pipes in the fluid system 20. In the illustrated embodiment, high-pressure inlet 118 forms part of the clutch actuation fluid circuit 60 and receives clutch actuation fluid pumped by the second pump 58. Low-pressure inlet 122 forms part of the cooling and lubrication fluid circuit 42 and receives cooling and lubrication fluid pumped by the first pump 52. Within the valve block 100, interconnect 102 is formed by a passage fluidly connecting the high-pressure inlet 118 to the low-pressure inlet 122.

[0032] The fluid system 40 may also include a pressure relief valve 86. The pressure relief valve 86 may be configured to open in response to excessive pressure in the clutch actuation fluid circuit 60 to allow excessive pressure to be released to, for example, port 70. When the clutch actuation fluid pressure drops, such as when the engine 14 is off and the second pump 58 is off, some fluid from the cooling and lubrication fluid circuit 42 may flow through the interconnect 102 to the high-pressure side of the fluid system 20, thereby providing cooling and lubrication fluid to port 74, and thus providing at least some cooling and lubrication fluid to the clutch 30. As a result, even when the clutch 30 is disengaged and no high-pressure clutch actuation fluid flow is provided, some cooling and lubrication fluid will still flow to the clutch 30.

[0033] Industrial applicability

[0034] Still refer to the attached figures for the overall layout, but also refer to [the following text is missing here]. Figure 10 A cross-sectional side view of the motor assembly 18 is shown, illustrating its additional features and details. (See attached image.) Figure 10 The depicted disengagement clutch 30 may include a first rotatable component 134 configured to rotate with the engine output shaft 16, and a second rotatable component configured to rotate with the drive shaft 26. The clutch 30 also includes a clutch friction element 138 and a piston 140 exposed to fluid pressure in a clutch actuation fluid chamber 142. Changing the pressure of the clutch actuation fluid supplied to the fluid chamber 142 can engage or disengage the clutch friction element 138, and rotatably engage or disengage the first rotatable component 134 and the second rotatable component 136.

[0035] The ability to selectively connect the engine output shaft 16 to the drive shaft 26 enables the propulsion system 12 to operate in several different modes as described above. In embodiments, the propulsion system 12 can operate in engine-only mode, electric motor-only mode, and hybrid mode. In some embodiments, the electric motor 20 can operate as a motor-generator unit or MGU, enabling the drive shaft 26 to rotate to generate electricity, which can be used, for example, for the onboard machine 8 and / or stored in an onboard energy storage device. The engine 14 can be used to rotate the electric motor 20, or to regenerately rotate the electric motor 20 via the braking mechanism 8.

[0036] In an embodiment, operating the propulsion system 12 may include, in a motor-only mode, applying torque to the drive shaft 26 via the rotor 22, which is rotatably coupled to the drive shaft 26 via the stator coils 24 in the energized motor 20, when the disengagement clutch 30 is disengaged. Operating the propulsion system 12 may also include engaging the disengagement clutch 30, which is positioned together with the motor 20 in a common housing 32, to connect the drive shaft 26 to the engine output shaft 16. With the disengagement clutch 30 engaged, in the engine-only mode of the propulsion system 12, torque can be applied to the drive shaft 26 via the engine output shaft 16, while the stator coils 24 are de-energized. In a hybrid mode, torque can be applied to the drive shaft 26 via the energized stator coils 24 when the disengagement clutch 30 is engaged. The final drive unit 50 can operate in each of the motor-only mode, engine-only mode, and hybrid mode via the torque applied to the drive shaft 26.

[0037] Therefore, it can be understood that by changing the fluid pressure used to actuate the release clutch 30 and selectively energizing the stator coils 24, thereby engaging or disengaging the release clutch 30, the propulsion system 12 can switch between various modes. Torque can be applied to the drive shaft 26 solely through the engine 10, solely through the energized stator coils 24, or both. Regardless of whether the release clutch 30 is engaged or disengaged, the first pump 52 is operated via the rotation of the drive shaft 26. Thus, regardless of the specific operating mode of the propulsion system 12, based on the operation of the first pump 52, fluid for cooling and lubrication is supplied to the electric motor 20 and the release clutch 30.

[0038] This specification is for illustrative purposes only and should not be construed as limiting the scope of the invention in any way. Therefore, those skilled in the art will understand that various modifications can be made to the currently disclosed embodiments without departing from the full and reasonable scope and spirit of the invention. Other aspects, features, and advantages will become apparent from a study of the accompanying drawings and appended claims. As used herein, the articles “a” and “an” are intended to include one or more items and may be used interchangeably with “one or more.” The term “an” or similar language is used where only one item is desired. Furthermore, as used herein, the terms “has,” “have,” “having,” etc., are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “at least partially based on,” unless otherwise explicitly stated.

Claims

1. A propulsion system (12), comprising: An engine (14) including an engine output shaft (16); An electric motor assembly (18) comprising an electric motor (20) having a rotor (22) and a stator (24), a drive shaft (26), an output gear (28) fixed and rotating together with the drive shaft, and a hydraulically actuated disengagement clutch (30) operably positioned between the drive shaft and the engine output shaft; and The motor assembly further includes a common housing (32) having a plurality of attached housing components (34, 36, 38) positioned together around the motor and the disengagement clutch, and the fluid system (40) including a fluid circuit for cooling and lubricating at least one of the motor or the disengagement clutch.

2. The system according to claim 1, wherein: The output gear is connected to a takeoff gear train (54) that is at least partially located in the common housing; The fluid system further includes a pump (52) that rotates via the takeoff gear train and is mounted on the common housing; and The pump includes a low-pressure cooling and lubrication pump, and the fluid system further includes a high-pressure clutch actuation pump (58).

3. The system according to claim 1 or 2, wherein the common housing further includes a cooling and lubrication fluid supply port (70, 71), a cooling and lubrication fluid discharge port (72, 73), a clutch actuation fluid supply port (74), a clutch actuation fluid discharge port (76), and a common fluid reservoir (78) mounted on the common housing.

4. The system according to any one of claims 1-3, wherein the plurality of housing components include a clutch housing component (38), a gear train housing component (34), and an electric motor housing component (36) attached between the clutch housing component and the gear train housing component.

5. An electric motor assembly (18), comprising: An electric motor (20) includes a rotor (22) and a stator (24), a drive shaft (26), and an output gear (28) fixed to rotate with the drive shaft; A disengagement clutch (30) is connected to the drive shaft and is adjustable from a disengaged state to an engaged state to connect the drive shaft to the engine output shaft (16). as well as A common housing (32) includes a clutch housing component (38) positioned around the disengaging clutch, a gear train housing component (34) positioned around the output gear, and an electric motor housing component (36) positioned around the electric motor and attached between the gear train housing component and the clutch housing component.

6. The electric motor assembly of claim 5, wherein the common housing further has at least one cooling and lubricating fluid supply port (70, 71) formed therein, and an actuation fluid supply port (74) for actuating the disengagement clutch; and The motor assembly further includes a first mounting rod (104) attached to a first side of the housing and a second mounting rod (104) attached to the opposite side of the housing.

7. The motor assembly according to claim 5 or 6, wherein: The gear housing component includes a pump mounting surface (98) and a reservoir mounting surface (96); The gear housing component includes a downwardly suspended fluid collection section (94) that is positioned to receive cooling and lubricating fluid discharged through a common housing under gravity, and the reservoir mounting surface is at least partially formed on the fluid collection section.

8. The motor assembly according to any one of claims 5-7, wherein: The clutch housing component includes a valve block mounting surface (106); and The at least one cooling and lubricating fluid supply port and the actuation fluid supply port are formed in the valve block mounting surface.

9. The electric motor assembly according to any one of claims 5-8, further comprising a gear train (54) including the output gear and positioned within the gear train housing component.

10. The motor assembly according to any one of claims 5-9, wherein: The motor housing component includes a first end flange (110) bolted to the gear housing component and a second end flange (112) bolted to the clutch housing component; and The motor housing component includes a cylindrical central portion (108) extending from the first end flange to the second end flange.

11. A method of operating a propulsion system (12), comprising: In the motor-only mode of the propulsion system (12), torque is applied to the drive shaft (26) in the motor (20) via energizing the stator coil (24) in the motor to rotatably connect to the rotor (22) of the drive shaft; Engage the disengagement clutch (30) located in the common housing (32) with the electric motor to connect the drive shaft to the engine output shaft (16) of the engine (14); When the disengagement clutch is engaged and the stator coil is de-energized, in the engine-only mode of the propulsion system, torque is applied to the drive shaft via the engine output shaft; In the hybrid mode of the propulsion system, torque is applied to the drive shaft by energizing the stator coils when the disengagement clutch is engaged; as well as In each of the electric motor-only mode, engine-only mode, and hybrid mode, the final drive unit (50) in the machine (8) is operated via the torque applied to the drive shaft.

12. The method of claim 11, wherein the operation of the final drive device includes a final drive device for operating a propeller (53) coupled to the ship.

13. The method according to claim 11 or 12, further comprising operating a cooling and lubricating fluid pump (52) for the electric motor arranged in the lubrication fluid circuit (42), and an actuation fluid pump (58) for the disengagement clutch arranged in the actuation fluid circuit (60), wherein the lubrication fluid circuit and the actuation fluid circuit share a common fluid reservoir (78).

14. The method of claim 13, wherein operating the cooling and lubrication fluid pump comprises operating the cooling and lubrication fluid pump via the takeoff gear train (54) of the electric motor, and operating the actuation fluid pump comprises operating the actuation fluid pump via the gear train (56) of the engine.

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