Hybrid marine propulsion unit

Abstract

To prevent complication of an internal structure of a hybrid ship propulsion machine and inhibit deterioration of cruising performance of a ship during planing.SOLUTION: A hybrid outboard engine 1 includes: an internal combustion drive propulsion unit 11 which generates propulsion power of a ship by an internal combustion engine; and an electric propulsion unit 31 which generates propulsion power of the ship by an electric motor. The electric propulsion unit 31 includes a structure of a jet propulsion device which generates jet flow to obtain propulsion power. The electric propulsion unit 31 is detachably attached to a rear part of a middle case 21 of the internal combustion drive propulsion unit 11 and arranged at a position higher than an anti-cavitation plate 23 so that each suction port 36 of a duct 32 sinks below a surface of water during low speed traveling, which is not in a planing state of the ship and each suction port 36 gets out from under the surface of the water during planing of the ship.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a hybrid marine propulsion device that includes an internal combustion propulsion unit powered by an internal combustion engine and an electric propulsion unit powered by an electric motor. [Background technology]

[0002] 2. Description of the Related Art Conventionally, marine propulsion units powered by internal combustion engines have been common, but recently, marine propulsion units powered by electric motors have also become popular.

[0003] When comparing internal combustion engines and electric motors, it can be said that internal combustion engines are superior to electric motors in terms of the ability to operate a ship at high speeds for long periods of time. Considering that a large-capacity battery is required to operate an electric motor at high speeds for long periods of time, internal combustion engines are currently more practical. On the other hand, it can be said that electric motors, which can generate high torque even in a low rotation range, are superior to internal combustion engines in terms of the ability to operate a ship at extremely low speeds. It can also be said that electric motors are superior to internal combustion engines in terms of quietness when operating at low speeds. With internal combustion engines, the loud driving noise can be unpleasant to the ears when operating at low speeds.

[0004] Another method is to use both an internal combustion engine and an electric motor as the power source for a marine propulsion system. This method makes it possible to take advantage of the high performance of the internal combustion engine at high speeds while using the electric motor to compensate for the lack of performance of the internal combustion engine at low speeds. This method also makes it possible to suppress noise during low-speed navigation.

[0005] Specifically, there are two methods for using both an internal combustion engine and an electric motor as the power source for a marine propulsion unit.

[0006] The first method is to prepare an internal combustion-driven marine propulsion unit powered solely by an internal combustion engine and an electric marine propulsion unit powered solely by an electric motor, and equip the marine vessel with these two types of marine propulsion units. For example, this would involve installing both an internal combustion-driven outboard motor and an electric outboard motor on a single marine vessel. The second method is to equip the marine vessel with a hybrid marine propulsion unit powered by both an internal combustion engine and an electric motor.

[0007] Patent Document 1 listed below describes an outboard motor equipped with both an internal combustion engine and an electric motor as power sources. This outboard motor incorporates an internal combustion engine and an electric motor, and is configured so that the power of the internal combustion engine and the power of the electric motor are transmitted to a common propeller via a common main drive shaft and a common propeller shaft. Figure 2 of Patent Document 1 shows a mechanism for transmitting the power of the internal combustion engine and the power of the electric motor to the main drive shaft, and this mechanism is equipped with an automatic centrifugal clutch and multiple gears. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-8329 Summary of the Invention [Problem to be solved by the invention]

[0009] According to the method of using both an internal combustion engine and an electric motor as the power source of a marine propulsion unit, as described above, the advantages of the internal combustion engine can be utilized while the disadvantages of the internal combustion engine can be compensated for by the electric motor, thereby improving the marine vessel's sailing performance over a wide range of speeds.

[0010] However, the method of providing a boat with an internal combustion-driven boat propulsion unit that uses only an internal combustion engine as a power source and an electric boat propulsion unit that uses only an electric motor as a power source has the following problems.

[0011] Installing both an internal combustion-driven boat propulsion unit and an electric boat propulsion unit requires a certain amount of space. Therefore, it is difficult to install both an internal combustion-driven boat propulsion unit and an electric boat propulsion unit on a small boat with limited space at the stern. Even on a medium-sized boat, for example, if multiple internal combustion-driven outboard motors are already installed on the boat, it can be difficult to install an electric outboard motor on the boat.

[0012] Furthermore, with regard to the method of providing a hybrid marine propulsion unit, as in the outboard motor described in Patent Document 1, the mechanism for transmitting the power of the internal combustion engine and the power of the electric motor to a common drive shaft is complex, resulting in high manufacturing costs.

[0013] Therefore, the inventors of the present application devised a method of externally mounting an electric jet propulsion device including a duct, an electric motor, and an impeller mounted within the duct and connected to the output shaft of the electric motor to an internal combustion-driven boat propulsion unit powered solely by an internal combustion engine. With this method, an internal combustion-driven boat propulsion unit with an external electric jet propulsion unit is mounted on a boat, so that the only boat propulsion unit directly mounted on the boat is the internal combustion-driven boat propulsion unit. Therefore, even in small boats with limited space at the stern or boats already equipped with multiple internal combustion-driven outboard motors, an internal combustion-driven boat propulsion unit with an external electric jet propulsion unit can be easily mounted, enabling both internal combustion-driven and electric propulsion to be obtained. Furthermore, with this method, because the electric jet propulsion device is externally attached to the internal combustion-driven marine propulsion unit, the propeller rotated by the power of the internal combustion engine and the impeller rotated by the power of the electric motor are separate, and the mechanism that transmits power from the internal combustion engine to the propeller and the mechanism that transmits power from the electric motor to the impeller are separate. Therefore, when obtaining propulsive force from the internal combustion engine and propulsive force from the electric motor, it is not necessary to provide the marine propulsion unit with a complex mechanism that transmits the power of the internal combustion engine and the power of the electric motor to a common drive shaft.

[0014] However, the method of externally mounting an electric jet propulsion unit to an internal combustion-driven boat propulsion unit has the following problem. An electric jet propulsion unit externally mounted to an internal combustion-driven boat propulsion unit is mostly submerged below the waterline. Therefore, when the boat is moving, water hits the electric jet propulsion unit, creating resistance to the boat's movement. This resistance increases when the boat is planing, potentially reducing the boat's sailing performance when planing.

[0015] The present invention has been made in consideration of the problems described above, and an object of the present invention is to provide a hybrid marine propulsion device that can prevent the internal structure from becoming complicated and can suppress a decrease in the marine vessel's sailing performance during planing. [Means for solving the problem]

[0016] In order to solve the above problems, the present invention The first hybrid marine propulsion systemis a hybrid marine propulsion device comprising an internal combustion-driven propulsion unit that generates a propulsive force for a marine vessel by an internal combustion engine, and an electric jet propulsion unit that generates a propulsive force for the marine vessel by an electric motor, wherein the internal combustion-driven propulsion unit comprises the internal combustion engine, a propeller shaft that rotates by power output from the internal combustion engine, a power transmission mechanism that transmits the power output from the internal combustion engine to the propeller shaft, a first housing that houses the power transmission mechanism and the propeller shaft, a propeller attached to the propeller shaft, and an anti-cavitation plate that is provided in the first housing and arranged above the propeller, and the electric jet propulsion unit has a water jet at one end. the electric jet propulsion unit is attached to the first housing and is positioned higher than the anti-cavitation plate so that the intake port is submerged below the water surface when the vessel is moving at low speed and not in a planing state, and the intake port is above the water surface when the vessel is planing. A plate member is provided above the discharge port to guide water into the discharge port when the impeller is rotated in the reverse direction to generate a jet flow in the reverse direction. It is characterized by: A second hybrid marine propulsion device of the present invention is a hybrid marine propulsion device comprising an internal combustion-driven propulsion unit that generates propulsive force for the marine vessel using an internal combustion engine, and an electric jet propulsion unit that generates propulsive force for the marine vessel using an electric motor, wherein the internal combustion-driven propulsion unit comprises the internal combustion engine, a propeller shaft that rotates by power output from the internal combustion engine, a power transmission mechanism that transmits the power output from the internal combustion engine to the propeller shaft, a first housing that houses the power transmission mechanism and the propeller shaft, a propeller attached to the propeller shaft, and an anti-cavitation plate that is provided in the first housing and arranged above the propeller, and the electric jet propulsion unit has an intake port at one end that takes in water. the electric jet propulsion unit is attached to the first housing and is positioned higher than the anti-cavitation plate so that the intake port is submerged below the water surface when the vessel is moving at low speed and not planing, and the intake port is above the water surface when the vessel is planing, and a plurality of the exhaust ports are arranged vertically at the other end of the duct. [Effects of the Invention]

[0017] According to the present invention, it is possible to prevent the internal structure of the hybrid marine vessel propulsion unit from becoming complicated, and to suppress a decrease in the marine vessel running performance during planing. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is an explanatory diagram showing a hybrid outboard motor as an embodiment of a hybrid marine propulsion device according to the present invention, viewed from the left side; [Figure 2] FIG. 1 is a perspective view showing a lower portion of a hybrid outboard motor according to an embodiment of the present invention, as viewed from the upper left rear side. [Figure 3] 1 is an external view showing an electric propulsion unit of a hybrid outboard motor according to an embodiment of the present invention, viewed from above; [Figure 4] 4 is a cross-sectional view of the electric propulsion unit taken along the line IV-IV in FIG. 3, viewed from the left. [Figure 5] 1A and 1B are explanatory diagrams showing the positional relationship between the hybrid outboard motor and the water surface according to an embodiment of the present invention, in which (A) in the figure shows the positional relationship between the hybrid outboard motor and the water surface when moving at low speed, and (B) in the figure shows the positional relationship between the hybrid outboard motor and the water surface when planing. [Figure 6] FIG. 2 is an explanatory diagram showing a structure for attaching an electric propulsion unit to an internal combustion propulsion unit in a hybrid outboard motor according to an embodiment of the present invention. [Figure 7] FIG. 2 is an explanatory diagram showing the electrical configuration of the hybrid outboard motor according to the embodiment of the present invention. [Figure 8] 10 is an explanatory diagram showing a hybrid inboard / outboard motor that is another embodiment of a hybrid marine propulsion device according to the present invention. FIG. [Figure 9] 1 is an explanatory diagram showing an electric outboard motor using an electric propulsion unit according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0019] A hybrid marine vessel propulsion device according to an embodiment of the present invention includes an internal combustion-driven propulsion unit that generates propulsive force for the marine vessel using an internal combustion engine, and an electric jet propulsion unit that generates propulsive force for the marine vessel using an electric motor.

[0020] The internal combustion-driven propulsion unit includes an internal combustion engine, a propeller shaft that rotates using power output from the internal combustion engine, a power transmission mechanism that transmits the power output from the internal combustion engine to the propeller shaft, a first housing that houses the power transmission mechanism and the propeller shaft, a propeller attached to the propeller shaft, and an anti-cavitation plate that is provided in the first housing and positioned above the propeller.

[0021] The electric jet propulsion unit includes a duct having an intake port at one end for drawing in water and an outlet at the other end for discharging the water drawn in from the intake port, an electric motor, a second housing attached to the duct and housing the electric motor, an impeller provided within the duct for generating a jet flow, and an impeller shaft for transmitting power output from the electric motor to the impeller and rotating the impeller.

[0022] The electric jet propulsion unit is attached to the first housing and positioned higher than the anti-cavitation plate so that the duct intake is submerged below the water surface when the vessel is moving at low speeds and not planing, and is above the water surface when the vessel is planing.

[0023] By setting the mounting position of the electric jet propulsion unit in this manner, it is possible to reduce the resistance caused by water hitting the electric jet propulsion unit when the vessel is planing, and to prevent this resistance from reducing the vessel's sailing performance when planing.

[0024] Furthermore, the hybrid marine propulsion device of this embodiment can be configured by externally attaching an electric jet propulsion unit separate from the internal combustion propulsion unit to the first housing of the internal combustion propulsion unit. This makes it possible to generate propulsive force from the internal combustion engine and propulsive force from the electric motor without using a complex mechanism for transmitting the power of the internal combustion engine and the power of the electric motor to a common drive shaft. This prevents the internal structure of the hybrid marine propulsion device from becoming too complicated. [Example]

[0025] A hybrid outboard motor as an embodiment of a hybrid marine propulsion device of the present invention will be described below with reference to the drawings. In the embodiment, when describing the directions of front (Fd), rear (Bd), left (Ld), right (Rd), up (Ud), and down (Dd), please refer to the arrows at the bottom right of Figures 1 to 6, 8, and 9.

[0026] (Hybrid outboard motor) Fig. 1 shows a hybrid outboard motor 1 according to an embodiment of the present invention as seen from its left side, while Fig. 2 shows the lower part of the hybrid outboard motor 1 as seen from its upper left rear side.

[0027] The hybrid outboard motor 1 is an outboard motor powered by both an internal combustion engine and an electric motor. As shown in FIG. 1, the hybrid outboard motor 1 includes an internal combustion propulsion unit 11 and an electric propulsion unit 31. The internal combustion propulsion unit 11 generates the propulsive force of the boat using an internal combustion engine. Meanwhile, the electric propulsion unit 31 generates the propulsive force of the boat using an electric motor. The electric propulsion unit 31 is configured as a jet propulsion device that generates a jet flow to obtain propulsive force. As shown in FIG. 2, the electric propulsion unit 31 is attached to the outside of the internal combustion propulsion unit 11 above the anti-cavitation plate 23. Hereinafter, the hybrid outboard motor 1 will be simply referred to as the "outboard motor 1." The electric propulsion unit 31 is a specific example of an "electric jet propulsion unit."

[0028] (Internal Combustion Driven Propulsion Unit) The internal combustion propulsion unit 11 comprises an internal combustion engine 12 mounted on the top of the outboard motor 1, a drive shaft 13 extending vertically in the vertical middle of the outboard motor 1, a gear mechanism 14 mounted on the bottom of the outboard motor 1, a propeller shaft 15 mounted on the bottom of the outboard motor 1 and extending in the fore-and-aft direction, and a propeller 16 attached to the rear end portion of the propeller shaft 15.

[0029] The internal combustion engine 12 is, for example, a four-stroke engine that uses gasoline as fuel. The power output from the internal combustion engine 12 is transmitted to a propeller shaft 15 via a drive shaft 13 and a gear mechanism 14. As a result, the propeller shaft 15 rotates based on the power of the internal combustion engine 12. The propeller 16 rotates together with the propeller shaft 15, generating propulsion power for the vessel. In addition, a clutch (not shown) is provided in the gear mechanism 14, and operation of the clutch can switch whether or not the power of the internal combustion engine 12 is transmitted to the propeller shaft 15, and can switch the rotation direction of the propeller shaft 15.

[0030] The internal combustion propulsion unit 11 also includes a top cowl 18, a bottom cowl 19, an upper case 20, a middle case 21, and a gear case (lower case) 22. For ease of understanding, the exposed portions of the middle case 21 in Figures 1 and 5 are marked with a dot pattern.

[0031] The top cowling 18 and the bottom cowling 19 cover the internal combustion engine 12. The drive shaft 13 is housed in the upper case 20 and the middle case 21. The gear mechanism 14 and the front end portion of the propeller shaft 15 are housed in the gear case 22. An anti-cavitation plate 23 that suppresses air intake into the propeller 16 is provided above the propeller 16 in the upper rear portion of the gear case 22. A clamp bracket 24 is provided in front of the upper case 20 for mounting and securing the outboard motor 1 to the transom of the boat. A swivel bracket 25 is attached to the clamp bracket 24, and the outboard motor 1 is rotatably supported by the swivel bracket 25 via a steering shaft 26 so that it can be turned left and right.

[0032] The drive shaft 13 and the gear mechanism 14 are specific examples of a "power transmission mechanism." Furthermore, the upper case 20, the middle case 21, and the gear case 22 are specific examples of a "first housing section."

[0033] (Electric propulsion section) Fig. 3 shows the electric propulsion unit 31 as viewed from above. Fig. 4 shows a cross section of the electric propulsion unit 31 taken along section line IV-IV in Fig. 3 as viewed from the left.

[0034] As shown in FIGS. 3 and 4, the electric propulsion unit 31 includes a duct 32, an electric motor 48, an impeller 49, an impeller shaft 50, an inverter 53, and a housing case 54.

[0035] The duct 32 is formed into a generally S-shaped pipe from, for example, a metal material. The duct 32 includes two intake sections 33 located at the front end of the duct 32, an exhaust section 34 located at the rear end of the duct 32, and an intermediate section 35 located between the intake sections 33 and the exhaust sections 34 in the duct 32.

[0036] As shown in Figure 3, the two suction sections 33 are aligned in the left-right direction, and each suction section 33 extends in the front-rear direction. Each suction section 33 has an inlet port 36 at its front end, and each inlet port 36 faces forward. As can be seen from Figure 4, the inner diameter of each suction section 33 is smaller than the inner diameter of the intermediate section 35 and the inner diameter of the discharge section 34. The diameter of each suction port 36 is also smaller than the diameter of the first discharge port 41.

[0037] The intermediate section 35 is a single unit that extends in the vertical direction. Two suction sections 33 are connected to the lower end of the intermediate section 35. The sections extending from the rear ends of the two suction sections 33 to the lower end of the intermediate section 35 are gently curved. The discharge section 34 is connected to the upper end of the intermediate section 35. The section extending from the upper end of the intermediate section 35 to the front end of the discharge section 34 is gently curved.

[0038] The discharge portion 34 is a single unit that extends in the front-to-rear direction. A first discharge port 41 is provided at the rear end of the discharge portion 34, and the first discharge port 41 faces rearward. As shown in FIG. 2, a plurality of fins 45 are provided at predetermined intervals around the inner periphery of the first discharge port 41.

[0039] In addition, a plate member 46 is provided above the first outlet 41. The plate member 46 has the function of guiding water into the first outlet 41 when the impeller 49 is rotated in the reverse direction to generate a jet flow in the reverse direction (from the first outlet 41 toward each inlet 36). The plate member 46 is attached to the outlet portion 34.

[0040] In addition to the first exhaust port 41, the duct 32 is also provided with a second exhaust port 42 and a third exhaust port 43. The second exhaust port 42 and the third exhaust port 43 are arranged in the rear portion of the peripheral wall of the intermediate section 35. The second exhaust port 42 and the third exhaust port 43 each face rearward. The second exhaust port 42 and the third exhaust port 43 are also aligned in the vertical direction. The second exhaust port 42 is arranged below the first exhaust port 41, and the third exhaust port 43 is arranged below the second exhaust port 42. The diameters of the second exhaust port 42 and the third exhaust port 43 are each smaller than the diameter of the first exhaust port 41.

[0041] As shown in FIG. 4, the electric motor 48 is disposed above the duct 32. The electric motor 48 is, for example, a brushless motor. The electric motor 48 is housed in a housing case 54. The housing case 54 has, for example, a cylindrical outer shape and a completely waterproof structure. The housing case 54 is attached to the duct 32. Specifically, as shown in FIG. 2, the front part of the housing case 54 is fixed via two supports 55 to the upper part of a mounting bracket 56 fixed to the middle part 35 of the duct 32, and the rear part of the housing case 54 is fixed via another two supports 55 to the outer periphery of the rear part of the discharge part 34 of the duct 32. The housing case 54 is a specific example of a "second housing part."

[0042] The impeller 49 rotates by the power of the electric motor 48 and generates a jet flow. As shown in Fig. 4, the impeller 49 is provided inside the duct 32. The impeller 49 is disposed in the middle portion 35 of the duct 32, in a region below the third outlet 43.

[0043] The impeller shaft 50 transmits power output from the electric motor 48 to the impeller 49 to rotate the impeller 49. The impeller shaft 50 extends in the vertical direction, with the upper end of the impeller shaft 50 connected to the output shaft of the electric motor 48 and the impeller 49 attached to the lower end of the impeller shaft 50. The upper end portion of the impeller shaft 50 is inserted into the accommodating case 54 through an insertion hole 51 formed in the lower surface of the accommodating case 54. The lower end portion of the impeller shaft 50 is inserted into the duct 32 through an insertion hole 52 formed in an upper part of the peripheral wall of the intermediate portion 35 of the duct 32. The gap between the insertion hole 51 and the impeller shaft 50 is sealed to prevent water from entering the accommodating case 54.

[0044] The inverter 53 is a circuit that controls the driving of the electric motor 48. The inverter 53 is housed in a housing case 54.

[0045] The electric propulsion unit 31 operates as follows. When the electric motor 48 is driven to rotate the impeller shaft 50 and the impeller 49 in the forward direction while the intake ports 36 are submerged below the water surface, a jet flow is generated in the forward direction (from the intake ports 36 toward the first outlet ports 41). That is, water is drawn into the duct 32 through the intake ports 36, and the water drawn into the duct 32 is discharged rearward from the first outlet ports 41, the second outlet ports 42, and the third outlet ports 43, respectively. This generates a propulsive force that moves the vessel forward. On the other hand, when all or part of the first outlet port 41 is submerged below the water surface, when the electric motor 48 is driven to rotate the impeller shaft 50 and the impeller 49 in the reverse direction, a jet flow is generated in the reverse direction (from the first outlet ports 41 toward the intake ports 36). That is, water is drawn into the duct 32 from the first outlet 41, the second outlet 42, and the third outlet 43, and the water drawn into the duct 32 is discharged forward from each of the inlets 36. This generates a propulsive force that moves the boat backward. When a jet flow in the reverse direction is generated, the plate member 46 makes it easier for the water to flow into the first outlet 41.

[0046] (Layout of electric propulsion unit) 1 and 2, the electric propulsion unit 31 is disposed below and behind the internal combustion propulsion unit 11, and is attached to the rear of the middle case 21. The electric propulsion unit 31 is located above the propeller 16 of the internal combustion propulsion unit 11. The electric propulsion unit 31 is also located at a higher position than the anti-cavitation plate 23.

[0047] Specifically, the two intake sections 33 of the duct 32 are located above the anticavitation plate 23 and are arranged to sandwich the upper rear section of the gear case 22 on either side. The two intake ports 36 are located above the anticavitation plate 23 and are arranged on the left and right sides of the upper rear section of the gear case 22, respectively. The middle section 35 and exhaust section 34 of the duct 32 are located higher than the anticavitation plate 23 and are arranged in the left-right center behind the middle case 21. The first exhaust port 41 is located higher than the anticavitation plate 23 and is arranged in the left-right center behind the upper part of the middle case 21. The second exhaust port 42 and the third exhaust port 43 are located higher than the anticavitation plate 23 and are arranged in the left-right center behind the middle case 21. Most of the storage case 54 is located higher than the top of the middle case 21.

[0048] As shown in Figure 5, the electric propulsion unit 31 is arranged so that each intake port 36 is submerged below the water surface when the vessel is moving at low speed and not in a planing state, and is positioned so that each intake port 36 is above the water surface when the vessel is planing.

[0049] That is, the two-dot chain line S1 in Figure 5(A) indicates the water surface position when the vessel is moving at low speed and not planing. When the vessel is moving at low speed and not planing, most of the exposed portions of the middle case 21 (the portions marked with dots in the figure) and the entire gear case 22 are submerged, and the anti-cavitation plate 23 is also submerged. Furthermore, when the vessel is moving at low speed and not planing, all or most of the duct 32 is submerged. Specifically, when the vessel is moving at low speed and not planing, all of the intake sections 33, all of the intake ports 36, all or most of the intermediate section 35, all or a lower portion of the discharge section 34, and all or a lower portion of the first discharge port 41 of the duct 32 are submerged. Meanwhile, the housing case 54 is above the water surface.

[0050] When the vessel is not in a planing state and moving at a low speed, the electric motor 48 is driven in response to the user's operation of the vessel to rotate the impeller 49. When the vessel is not in a planing state and moving at a low speed, all of the intake ports 36 and all or a lower portion of the first exhaust port 41 are submerged below the water surface, so that by rotating the impeller 49, propulsive force can be applied to the vessel.

[0051] Meanwhile, the two-dot chain line S2 in FIG. 5(B) indicates the water surface position when the boat is planing. When the boat is planing, the boat and outboard motor 1 rise and are higher relative to the water surface than when the boat is not planing and moving at a low speed. When the boat is planing, the water surface position becomes equal to the position of the anti-cavitation plate 23, and the entire middle case 21 and the upper part of the gear case 22 (the portion above the anti-cavitation plate 23) are above the water surface. Furthermore, when the boat is planing, all or most of the electric propulsion unit 31 is above the water surface. Specifically, when the boat is planing, all or most of the duct 32 (all or most of the intake ports 36 and all of the first exhaust port 41) are above the water surface. Of course, the housing case 54 is above the water surface.

[0052] When the vessel is planing, the electric motor 48 is stopped from driving, and the impeller 49 is stopped from rotating. When the vessel is planing, all or most of the electric propulsion unit 31 is above the water surface, thereby reducing resistance to the vessel's movement. That is, if all or most of the duct 32 were submerged underwater when the vessel was planing, the resistance generated by water hitting the duct 32 would impede the vessel's movement. Furthermore, if not only the duct 32 but also the housing case 54 were submerged underwater when the vessel was planing, the resistance would increase, further impeding the vessel's movement. In this embodiment, when the vessel is planing, all or most of the electric propulsion unit 31 is above the water surface, thereby reducing the generation of such resistance.

[0053] On the other hand, the storage case 54 protrudes from the water not only when the vessel is planing but also when the vessel is not planing but moving at a low speed, thereby reducing the resistance caused by water hitting the storage case 54 even when the vessel is not planing but moving at a low speed.

[0054] Furthermore, as the boat transitions from a low-speed moving state to a planing state, the boat and the outboard motor 1 gradually rise above the water surface. During this time, first, the first outlet 41 emerges above the water surface, then the second outlet 42, and then the third outlet 43. Furthermore, the driving of the electric motor 48 is stopped after the third outlet 43 emerges above the water surface. As a result, the propulsive force of the boat provided by the electric propulsion unit 31 gradually weakens as the boat transitions from a low-speed moving state to a planing state. This prevents a sudden and significant decrease in the propulsive force of the electric propulsion unit 31 at a point during the boat's transition from a low-speed moving state to a planing state, thereby stabilizing the boat's navigation. Furthermore, this method allows the propulsive force of the electric propulsion unit 31 to be gradually weakened as the boat transitions from a low-speed moving state to a planing state without requiring control such as gradually reducing the rotation speed of the electric motor 48.

[0055] (Installation of electric propulsion unit) FIG. 6 shows a structure for attaching the electric propulsion unit 31 to the internal combustion-driven propulsion unit 11. As shown in FIG. 6, a mounting bracket 56 is provided in front of the middle section 35 of the duct 32 in the electric propulsion unit 31. The mounting bracket 56 is fixed to the front portion of the outer surface of the peripheral wall of the middle section 35 of the duct 32. Meanwhile, a mounting plate 57 is fixed to the rear portion of the middle case 21 in the internal combustion-driven propulsion unit 11. The electric propulsion unit 31 is attached to the rear portion of the middle case 21 by fastening the mounting bracket 56 to the mounting plate 57 with fixing members 58 (e.g., bolts). This mounting structure allows the electric propulsion unit 31 to be easily attached to the outside of the internal combustion-driven propulsion unit 11. Furthermore, this mounting structure allows the electric propulsion unit 31 to be easily attached to and detached from the internal combustion-driven propulsion unit 11. The mounting bracket 56 is a specific example of a "mounting portion."

[0056] The mounting plate 57 is also provided with a mounting position change structure 59 that can change the mounting position of the electric propulsion unit 31 relative to the internal combustion-driven propulsion unit 11 in the vertical direction. Specifically, the mounting plate 57 has a plurality of holes 60 (e.g., threaded bolt holes) aligned in the vertical direction, to which fixing members 58 can be fixed (fastened). By selecting a hole to fix the fixing member 58 from the plurality of holes 60, the mounting position of the electric propulsion unit 31 in the vertical direction can be selected. Note that such a mounting position change structure may be provided on the mounting bracket 56 instead of the mounting plate 57.

[0057] (Outboard motor control) Fig. 7 shows the electrical configuration of the outboard motor 1. For example, a control unit 71 is provided on the top of the outboard motor 1. The control unit 71 is equipped with a microcomputer and the like. As shown in Fig. 7, a remote controller 72 is connected to the input side of the control unit 71. The internal combustion propulsion unit 11 and the inverter 53 of the electric propulsion unit 31 are connected to the output side of the control unit 71. The remote controller 72 is provided on the boat.

[0058] The operator of the vessel can operate the clutch by tilting the lever 73 of the remote controller 72 in the F direction or the R direction in Figure 7 to switch whether or not the power of the internal combustion engine 12 is transmitted to the propeller shaft 15 and to switch the rotation direction of the propeller shaft 15. The operator can also increase or decrease the rotation speed of the internal combustion engine 12 by tilting the lever 73 of the remote controller 72 in the F direction or the R direction. The operator can also switch between driving and stopping the electric motor 48 and increase or decrease the rotation speed by tilting the lever 73 of the remote controller 72 in the F direction or the R direction.

[0059] Specifically, when the operator places the lever 73 of the remote controller 72 in the neutral position (a state in which it is not tilted in either the F or R direction), the control unit 71 stops the internal combustion engine 12 (or places it in an idling state in which the power of the internal combustion engine 12 is not transmitted to the propeller shaft 15) and stops the electric motor 48 of the electric propulsion unit 31.

[0060] Furthermore, when the operator tilts the lever 73 of the remote controller 72 slightly in the F direction to move the vessel forward at an extremely slow speed, the control unit 71 keeps the internal combustion engine 12 stopped (or idling) and drives the electric motor 48 of the electric propulsion unit 31 to rotate the impeller 49 forward. As a result, the vessel moves forward at an extremely slow speed by the propulsive force of the electric propulsion unit 31.

[0061] Furthermore, when the operator moderately tilts the lever 73 of the remote controller 72 in the F direction to move the vessel forward at a speed that is not extremely slow but not enough to cause the vessel to plan, the control unit 71 operates the internal combustion engine 12 at low speed, transmits the rotation to the propeller shaft 15 to rotate the propeller 16 in the forward direction, and drives the electric motor 48 of the electric propulsion unit 31 to rotate the impeller 49 in the forward direction. As a result, the vessel moves forward at a low speed using the propulsive force of the internal combustion-driven propulsion unit 11 and the propulsive force of the electric propulsion unit 31.

[0062] Furthermore, when the operator tilts the lever 73 of the remote controller 72 significantly in the F direction to move the boat forward in a planing state, the control unit 71 first operates the internal combustion engine 12 at high speed to rotate the propeller 16 forward at high speed, and also drives the electric motor 48 of the electric propulsion unit 31 to rotate the impeller 49 forward. As a result, the boat accelerates using the propulsion force from the internal combustion-driven propulsion unit 11 and the propulsion force from the electric propulsion unit 31. Then, when the boat reaches a planing state (after the third outlet 43 leaves the water surface), the control unit 71 recognizes that the boat has reached a planing state based on the boat's speed, and stops the electric motor 48 while maintaining operation of the internal combustion engine 12. As a result, the boat planes using only the propulsion force from the internal combustion-driven propulsion unit 11.

[0063] As described above, in the outboard motor 1 according to an embodiment of the present invention, the electric propulsion unit 31 is attached to the rear of the middle case 21 of the internal combustion-driven propulsion unit 11, and is positioned higher than the anti-cavitation plate 23 so that the intake ports 36 of the ducts 32 are submerged below the water surface when the boat is moving at low speed and not planing, and are raised above the water surface when the boat is planing. By positioning the electric propulsion unit 31 in this way, it is possible to reduce the resistance caused by water hitting the electric propulsion unit 31 when the boat is planing, and to prevent this resistance from deteriorating the boat's sailing performance when planing.

[0064] In particular, by arranging each intake port 36 above the anti-cavitation plate 23, each intake port 36 can be positioned sufficiently above the water surface when the vessel is planing. This prevents a large amount of water from flowing into the duct 32 from the intake port 36 during planing, thereby preventing an increase in resistance that would hinder the vessel's navigation.

[0065] The outboard motor 1 of this embodiment is configured so that the electric propulsion unit 31, separate from the internal combustion propulsion unit 11, is externally attached to the internal combustion propulsion unit 11. Therefore, the mechanism (drive shaft 13, gear mechanism 14, and propeller shaft 15) that transmits the power of the internal combustion engine 12 to the propeller 16 in the internal combustion propulsion unit 11 and the impeller shaft 50 of the electric propulsion unit 31 are provided separately and are independent of each other. Therefore, the outboard motor 1 of this embodiment can generate propulsive force from the internal combustion engine and propulsive force from the electric motor without using a complex mechanism (such as an automatic centrifugal clutch or a mechanism with multiple gears as described in Patent Document 1) that transmits the power of the internal combustion engine and the power of the electric motor to a common drive shaft. This prevents the internal structure of the outboard motor 1 from becoming complicated.

[0066] Furthermore, in the electric propulsion unit 31 of the outboard motor 1 of this embodiment, a plate member 46 is provided above the first outlet 41 to guide water into the first outlet 41 when the impeller 49 is rotated in the reverse direction to generate a reverse jet. Therefore, even when the boat is moving backward at a low speed, the plate member 46 allows sufficient water to flow from the first outlet 41 into the duct 32, and also reduces the amount of air that flows into the duct 32. This ensures that propulsion force for moving the boat backward can be obtained.

[0067] Furthermore, in the duct 32 of the electric propulsion unit 31 of the outboard motor 1 of this embodiment, in addition to the first outlet 41, a second outlet 42 and a third outlet 43 are provided aligned in the vertical direction. As described above, this configuration makes it possible to prevent a sudden and significant drop in the propulsive force of the electric propulsion unit 31 at a point in time while the boat is transitioning from a low-speed moving state to a planing state, thereby stabilizing the boat's running.

[0068] The duct 32 of the electric propulsion unit 31 of the outboard motor 1 of this embodiment is provided with two intake ports 36 aligned in the left-right direction. This allows water to efficiently flow into the duct 32 through the two intake ports 36 when a forward jet flow is generated. Furthermore, because the two intake ports 36 are located on the left and right sides of the middle case 21, water in the duct 32 can be discharged in a balanced manner from the left to the right when a reverse jet flow is generated.

[0069] Furthermore, in the outboard motor 1 of this embodiment, the electric propulsion unit 31 is provided with a mounting bracket 56, the internal combustion propulsion unit 11 is provided with a mounting plate 57, and the electric propulsion unit 31 is detachably attached to the internal combustion propulsion unit 11 via the mounting bracket 56 and the mounting plate 57. This allows the user to easily attach or detach the electric propulsion unit 31 to or from the internal combustion propulsion unit 11 depending on the application of the outboard motor 1, providing high convenience. Furthermore, with the outboard motor 1 of this embodiment, the electric propulsion unit 31 can be easily attached externally to an existing internal combustion outboard motor, making it easy to convert an existing internal combustion outboard motor into a hybrid.

[0070] The outboard motor 1 of this embodiment also includes an attachment position change structure 59 that can change the attachment position of the electric propulsion unit 31 in the vertical direction relative to the internal combustion-driven propulsion unit 11. This makes it easy to adjust the attachment position of the electric propulsion unit 31 depending on the size of the outboard motor, the number of crew members or weight of cargo on the boat, or the draft.

[0071] Furthermore, the outboard motor 1 of this embodiment has an electric propulsion unit 31 in which the power source and thrust generating means (impeller), etc. are independent of the internal combustion propulsion unit 11. Therefore, even if the internal combustion propulsion unit 11 malfunctions and becomes inoperable while sailing, the boat can still be brought closer to the shore by using the electric propulsion unit 31.

[0072] Furthermore, with the outboard motor 1, the electric propulsion unit 31 is attached to the internal combustion-driven propulsion unit 11, so that by attaching the outboard motor 1 to a boat, it is possible to obtain both propulsive force from the internal combustion engine and propulsive force from the electric motor. Therefore, to obtain propulsive force from the internal combustion engine and propulsive force from the electric motor, it is not necessary to attach an internal combustion-driven outboard motor and an electric outboard motor to the boat. Therefore, even if the boat is small or even if the boat already has multiple internal combustion-driven outboard motors attached, it is possible to obtain propulsive force from the internal combustion engine and propulsive force from the electric motor.

[0073] Furthermore, with the outboard motor 1, the low-speed torque before planing can be easily compensated for by the electric propulsion unit 31. As a result, even if an internal combustion engine with improved torque performance in the high-speed range is employed, the boat can ensure high sailing performance or good acceleration performance at low speeds. Furthermore, because the low-speed movement of the boat can be compensated for by the electric propulsion unit 31, by employing a propeller designed for high-speed sailing as the propeller 16 of the internal combustion-driven propulsion unit 11, the boat's sailing performance at high speeds can be improved without degrading its sailing performance at low speeds. Furthermore, when the boat is traveling at low speeds, the operation of the internal combustion engine 12 can be stopped and the boat can be moved solely by the propulsion force of the electric propulsion unit 31, allowing the boat to travel at low speeds without emitting noise. Furthermore, the combined use of an internal combustion engine and an electric motor can improve fuel efficiency.

[0074] Furthermore, in the outboard motor 1 of this embodiment, an inverter 53 that controls the drive of the electric motor 48 is provided inside a housing case 54 of the electric propulsion unit 31. By combining the electric motor and inverter into a single unit in this way, the electric propulsion unit 31 can be easily attached externally to the internal combustion-driven propulsion unit 11.

[0075] 7, control signals and the like may be transmitted and received wirelessly between the control unit 71 and the inverter 53. This eliminates the need for a cable for transmitting and receiving control signals and the like between the control unit 71 and the inverter 53, making it even easier to attach and detach the electric propulsion unit 31 to and from the internal combustion-driven propulsion unit 11.

[0076] In the above embodiment, the electric propulsion unit 31 is attached to the rear of the middle case 21 of the internal combustion-driven propulsion unit 11. However, the position where the electric propulsion unit 31 is attached is not limited to the rear of the middle case 21, as long as it is higher than the anti-cavitation plate in any part of the middle case 21, gear case 22, or upper case 20, and the intake ports 36 of the ducts 32 are submerged below the water surface when the boat is moving at low speed and not planing, and the intake ports 36 are above the water surface when the boat is planing. The present invention also includes a configuration in which the electric propulsion unit 31 is attached to a frame or bracket that supports the middle case 21 or the like in the outboard motor 1.

[0077] Furthermore, in the above embodiment, two intake ports 36 are provided in the duct 32, but the number of intake ports may be one or three or more. Furthermore, in the above embodiment, three exhaust ports 41, 42, and 43 are provided, but the number of exhaust ports may be one or four or more. Furthermore, in the above embodiment, the duct 32 is formed in an S-shape, but the shape of the duct is not limited to this. Furthermore, multiple electric propulsion units may be attached to the internal combustion-driven propulsion unit 11.

[0078] Furthermore, the present invention is not limited to outboard motors, but can also be applied to inboard-outboard motors. Specifically, as shown in Fig. 8, an electric propulsion unit 31 may be attached to an internal combustion-driven inboard-outboard motor 82. This allows a hybrid inboard-outboard motor 81 to be constructed.

[0079] As shown in FIG. 9, an electric outboard motor 85 can be constructed by attaching the electric propulsion unit 31 to a frame 88 provided with a handlebar 86 and a clamp bracket 87.

[0080] Furthermore, the present invention can be modified as appropriate within the scope of the claims and the spirit or concept of the invention as can be read from the entire specification, and a hybrid marine propulsion device with such modifications is also included in the technical concept of the present invention. [Explanation of symbols]

[0081] 1 Hybrid outboard motor (hybrid marine propulsion unit) 11 Internal combustion propulsion unit 12 Internal combustion engine 13 Drive shaft (power transmission mechanism) 14 Gear mechanism (power transmission mechanism) 15 propeller shaft 16 propellers 20 Upper case (first storage section) 21 Middle case (first storage section) 22 Gear case (first housing section) 23 Anti-cavitation plate 31 Electric propulsion unit (electric jet propulsion unit) 32 Duct 36 Intake port 41 1st outlet 42 2nd outlet 43 3rd outlet 46 Plate member 48 Electric Motor 49 Impeller 50 impeller shaft 53 Inverter 54 Storage case (second storage section) 56 Mounting bracket (mounting part) 59 Mounting position change structure 81 Hybrid inboard / outboard motor (hybrid marine propulsion unit)

Claims

1. A hybrid marine propulsion device including an internal combustion-driven propulsion unit that generates a propulsive force for a marine vessel using an internal combustion engine, and an electric jet propulsion unit that generates a propulsive force for the marine vessel using an electric motor, The internal combustion-driven propulsion unit includes: the internal combustion engine; a propeller shaft that rotates by power output from the internal combustion engine; a power transmission mechanism that transmits power output from the internal combustion engine to the propeller shaft; a first housing portion that houses the power transmission mechanism and the propeller shaft; a propeller attached to the propeller shaft; an anti-cavitation plate provided in the first housing portion and arranged above the propeller, The electric jet propulsion unit includes: a duct having an intake port at one end for drawing in water and an outlet at the other end for discharging the water drawn in through the intake port; the electric motor; a second housing portion attached to the duct and housing the electric motor; an impeller provided in the duct to generate a jet; an impeller shaft that transmits power output from the electric motor to the impeller and rotates the impeller, the electric jet propulsion unit is attached to the first housing and is positioned higher than the anti-cavitation plate so that the intake port is submerged below the water surface when the vessel is not planing and moving at low speed, and the intake port is above the water surface when the vessel is planing; a plate member provided above the discharge port that guides water into the discharge port when the impeller is rotated in the reverse direction to generate a jet flow in the reverse direction.

2. A hybrid marine propulsion device comprising an internal combustion-driven propulsion unit that generates a propulsive force for a marine vessel using an internal combustion engine, and an electric jet propulsion unit that generates a propulsive force for the marine vessel using an electric motor, The internal combustion-driven propulsion unit includes: the internal combustion engine; a propeller shaft that rotates by power output from the internal combustion engine; a power transmission mechanism that transmits power output from the internal combustion engine to the propeller shaft; a first housing portion that houses the power transmission mechanism and the propeller shaft; a propeller attached to the propeller shaft; an anti-cavitation plate provided in the first housing portion and arranged above the propeller, The electric jet propulsion unit includes: a duct having an intake port at one end for drawing in water and an outlet at the other end for discharging the water drawn in through the intake port; the electric motor; a second housing portion attached to the duct and housing the electric motor; an impeller provided in the duct to generate a jet; an impeller shaft that transmits power output from the electric motor to the impeller and rotates the impeller, the electric jet propulsion unit is attached to the first housing and is positioned higher than the anti-cavitation plate so that the intake port is submerged below the water surface when the vessel is not planing and moving at low speed, and the intake port is above the water surface when the vessel is planing; A hybrid marine propulsion device, characterized in that a plurality of the exhaust ports are provided at the other end of the duct so as to be aligned in the vertical direction.

3. 3. The hybrid marine propulsion device according to claim 1, wherein the intake port is disposed above the anti-cavitation plate.

4. the electric jet propulsion unit is provided with an attachment portion for attaching the electric jet propulsion unit to the first housing portion, 4. The hybrid marine propulsion device according to claim 1, wherein the electric jet propulsion unit is detachably attached to the first housing unit via the attachment portion.

5. 5. The hybrid marine propulsion device according to claim 4, wherein the first housing portion or the mounting portion is provided with a mounting position change structure that can change the mounting position of the electric jet propulsion unit relative to the internal combustion-driven propulsion unit in the vertical direction.

6. 6. The hybrid marine propulsion device according to claim 1, wherein an inverter for controlling the driving of the electric motor is provided in the second housing portion.

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