Propulsion systems and ships

Abstract

This invention provides a propulsion mechanism and a ship that can obtain appropriate output characteristics in both cases: when generating thrust using electricity and when generating electricity. [Solution] The propulsion mechanism 100 includes an electric motor 30 that generates driving force for the thruster 12B when power is supplied to it, and a generator 31 that is configured separately from the electric motor 30 and generates power through regeneration of the thruster 12B. Furthermore, the propulsion mechanism 100 includes a shaft 32 that connects the thruster 12B, the electric motor 30, and the generator 31 as the same power system. The propulsion mechanism 100 can disconnect the electric motor 30 when the generator 31 is generating power. Therefore, the electric motor 30 can be set to obtain appropriate output characteristics in the electric propulsion mode, and the generator 31 can be set to obtain appropriate output characteristics in the regenerative power generation mode.

Description

Technical Field

[0006] , , , ,

[0001] The present invention relates to a propulsion mechanism and a ship.

Background Art

[0002] In recent years, ships that generate thrust using renewable energy such as wind power are known for reducing GHG gases such as CO2. For example, the ship described in Patent Document 1 includes a wind propulsion unit that propels the hull by wind power in addition to a propeller-based propulsion device on the hull.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, in the above-described ship, when the ship is propelled by the wind propulsion unit, the propeller may be rotated by the water flow to perform power generation by regeneration. Therefore, the propulsion mechanism may include a motor generator that can perform both electric drive and power generation. However, such a motor generator has a problem that when optimized according to the maximum output in the motor mode and the corresponding high rotation speed, the power generation efficiency decreases in the generator mode with a low output. In addition, when a mechanism for reducing the speed with a gear is provided on the shaft for the motor mode, there is a problem that the power generation efficiency decreases due to the influence of the gear in the generator mode.

[0005] Therefore, an object of the present invention is to provide a propulsion mechanism and a ship that can obtain appropriate output characteristics both when generating propulsion force by electric power and when performing power generation.

Means for Solving the Problems

[0006] [[ID=四十五]] The propulsion mechanism according to the present invention comprises a thruster that generates thrust, an electric motor that generates driving force for the thruster when power is supplied to it, a generator configured separately from the electric motor that generates power through regeneration of the thruster, a shaft that connects the thruster, electric motor, and generator as a single power system, and a connection part on the shaft that has a clutch or clutch gear for switching between connecting and disconnecting the electric motor and the generator, and switches between a power propulsion mode in which the electric motor generates driving force when connected by the connection part, and a regenerative power generation mode in which the generator generates power when disconnected by the connection part.

[0007] The propulsion mechanism according to the present invention comprises an electric motor that generates driving force for a thruster when power is supplied, and a generator that is configured separately from the electric motor and generates power through regeneration of the thruster. Furthermore, the propulsion mechanism includes a shaft that connects the thruster, electric motor, and generator as a single power system. This allows the electric motor and generator to be separate components within the same power system. The connection part can also be switched between connecting and disconnecting the electric motor and the generator. Therefore, the propulsion mechanism can disconnect the electric motor when the generator is generating power. Accordingly, the electric motor can be set to obtain appropriate output characteristics in electric propulsion mode, and the generator can be set to obtain appropriate output characteristics in regenerative power generation mode. As a result, appropriate output characteristics can be obtained in both cases: when generating thrust force with electric power and when generating power.

[0008] The thruster, generator, connector, and motor may be arranged along the shaft in that order. In this case, in electric propulsion mode, the connector is connected and the motor is connected to the thruster. By keeping the generator in an unloaded state, the driving force of the motor can be transmitted to the thruster efficiently. In regenerative power generation mode, the connector is disconnected and the motor is disconnected from the generator. This allows the generator to generate power without being affected by the motor.

[0009] The ship is equipped with the propulsion mechanism described above. This allows the ship to perform electric propulsion and regenerative braking effectively.

[0010] The ship is further equipped with a wind-powered propulsion unit that generates thrust using wind power. In this case, when the wind-powered propulsion unit is generating thrust using wind power, the propulsion mechanism can generate electricity in a regenerative power generation mode.

[0011] The wind propulsion unit is a rotor sail, and in regenerative power generation mode, the rotor sail may be driven by electricity generated by a generator. This allows the regenerative power obtained by sailing with the rotor sail to be used to drive the rotor sail itself, thereby improving energy efficiency.

[0012] The wind propulsion unit is a rotor sail, and the electric propulsion mode may have a first mode in which power is supplied to an electric motor, and a second mode in which power is supplied to both the electric motor and the rotor sail. In the first mode, the rotor sail is stopped, and the ship is propelled by the thrust of the propeller. In this case, the power source can also supply power to the electric motor in addition to the power supplied to the rotor sail. Therefore, the output of the electric motor can be increased. In the second mode, the ship can be propelled by both the thrust of the propeller and the wind power of the rotor sail. Therefore, the ship can be propelled while taking advantage of the benefits of both types of propulsion. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a propulsion mechanism and a ship that can obtain appropriate output characteristics in both cases: when generating thrust using electric power and when generating electricity. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic cross-sectional view showing an example of a ship according to an embodiment of the present invention. [Figure 2] (a) is a diagram illustrating the principle of a rotor sail, and (b) is a plan view of a ship. [Figure 3] This is a schematic diagram showing the propulsion mechanism in electric propulsion mode. [Figure 4] This is a schematic diagram showing the propulsion mechanism in regenerative power generation mode. [Figure 5] This is a schematic diagram showing the promotion mechanism related to the comparative example. [Modes for carrying out the invention]

[0015] Preferred embodiments of the present invention will be described below with reference to the drawings. In the following description, the terms "front" and "rear" correspond to the direction of travel of the hull, the term "side" corresponds to the left-right (width) direction of the hull, and the terms "up" and "down" correspond to the up-down direction of the hull.

[0016] Referring to Figure 1, the basic configuration of a vessel according to an embodiment of the present invention will be described. Figure 1 is a schematic cross-sectional view showing an example of a vessel according to an embodiment of the present invention. Vessel 1 is a vessel that transports petroleum-based liquid cargo such as crude oil or liquid gas, and is, for example, an oil tanker. However, the vessel is not limited to an oil tanker, and may be various types of vessels such as bulk carriers that transport ore or coal, LNG carriers, car carriers, etc.

[0017] As shown in Figure 1, the vessel 1 comprises a hull 11, a propeller 12, and a plurality of rotor sails 10 (wind propulsion units). The hull 11 has a bow 2, a stern 3, an engine room 4, and a cargo room 6. An upper deck 19 is provided on the upper part of the hull 11. The bow 2 is located on the forward side of the hull 11. The stern 3 is located on the aft side of the hull 11.

[0018] The propeller 12 mechanically generates the thrust of the hull 11, and for example, a screw propeller is used. The propeller 12 is installed below the waterline (the water surface of the sea W) at the stern 3 during propulsion. Also, below the waterline at the stern 3, an azimuth thruster 15 that also serves as a rudder for adjusting the propulsion direction is installed. In the example shown in FIG. 1, the ship 1 includes a plurality of propellers 12A and 12B. The plurality of propellers 12A and 12B are arranged to face each other in the front-rear direction. The propeller 12A is arranged on the bow side with respect to the propeller 12B and is connected to the main engine 16. The propeller 12B is connected to an electric motor 30 and a generator 31 (see FIG. 3) described later. Note that the ship 1 has a propulsion mechanism 100 including the propeller 12. The detailed configuration of the propulsion mechanism 100 will be described later.

[0019] The engine room 4 is provided at a position adjacent to the bow side of the stern 3. The engine room 4 is a compartment for arranging the main engine 16. Above the engine room 4, the living area 22 and the chimney 23 are provided. The pump room 5 is provided at a position adjacent to the bow side of the engine room 4. The pump room 5 is a compartment in which pumps 17 and the like are arranged. The cargo hold 6 is provided between the bow 2 and the engine room 4. The cargo hold 6 is a compartment for storing cargo. The cargo hold 6 is divided into a plurality of cargo spaces 26 and a plurality of ballast tanks 27 by adopting a double hull structure of the outer plate 20 and the inner bottom plate 21. The cargo space 26 loads the cargo carried by the ship 1. The ballast tank 27 stores a ballast water amount corresponding to the size of the ship and the like in order to adjust the draft and the like.

[0020] The rotor sail 10 is a mechanism that generates thrust by receiving wind force. As a result, the rotor sail 10 propels the hull 11 by the wind force. The rotor sail 10 is provided singly or plural (here, four) in the front-back, left-right directions on the upper deck 19 of the hull 11. As shown in Fig. 2(a), the rotor sail 10 includes a columnar rotor sail 41 (main body part) extending in the vertical direction and an electric motor for rotating the rotor sail 41. When the wind WD blows in from the side with respect to the rotor sail 41, at the rear side, the rotation direction of the rotor sail 41 and the direction of the wind WD are opposite to each other, and at the front side, the rotation direction of the rotor sail 41 and the direction of the wind WD coincide. Due to this, a pressure difference occurs before and after the rotor sail 41, and a thrust PF toward the front side is generated (Magnus effect). As shown in Fig. 2(b), when the wind WD blows from the side with respect to the hull 11, the hull 11 advances forward by the thrust PF of each rotor sail 10.

[0021] Next, the propulsion mechanism 100 will be described with reference to Figs. 3 and 4. Fig. 3 shows the propulsion mechanism 100 in the electric propulsion mode. Fig. 4 shows the propulsion mechanism 100 in the regenerative power generation mode. As shown in Fig. 3, the propulsion mechanism 100 includes a thruster 12B, an electric motor 30, a generator 31, a shaft part 32, and a connection part 33. Note that the electric motor 30, the generator 31, and the connection part 33 are arranged inside the hull 11.

[0022] The shaft part 32 is a member extending in the vertical direction. The shaft part 32 is a member that connects the thruster 12B, the electric motor 30, and the generator 31 as the same power system. In the present embodiment, along the shaft part 32, the thruster 12B, the generator 31, the connection part 33, and the electric motor 30 are arranged in this order from the bottom. The shaft part 32 includes a first shaft part 32a below the connection part 33 and a second shaft part 32b above the connection part 33.

[0023] The thruster 12B is a device that generates thrust. The thruster 12B has a propeller 12a that generates thrust by rotating in water. The propeller 12a is rotatably supported by a support 12b. The central axis 12c of the propeller 12a is arranged to extend horizontally. A first shaft portion 32a is provided extending upward from the upper end of the support 12b. Inside the support 12b, there is a mechanism such as gears that links the rotation of the first shaft portion 32a with the rotation of the propeller 12a. Therefore, when the first shaft portion 32a rotates, the propeller 12a rotates, and when the propeller 12a rotates, the first shaft portion 32a rotates.

[0024] The electric motor 30 is a device that generates the driving force for the thruster 12B when power is supplied to it. The electric motor 30 is a device that converts electrical energy into mechanical energy. The electric motor 30 includes a coil that generates a magnetic field by an externally supplied current and a magnet that interacts with the magnetic field. In this embodiment, the electric motor 30 does not function as a generator. A second shaft portion 32b is provided extending downward from the lower end of the electric motor 30. When the electric motor 30 generates rotational force, the second shaft portion 32b rotates at a desired rotational speed. The electric motor 30 rotates when power is supplied from a power supply source 50. The power supply source 50 is a battery or power source provided inside the ship 1.

[0025] The generator 31 generates electricity through regeneration from the thruster 12B. The generator 31 is a device that converts mechanical energy into electrical energy. The generator 31 includes a magnet that generates a magnetic field and a coil that is rotatably arranged within the magnetic field. When the propeller 12a of the thruster 12B rotates, the first shaft 32a rotates. The generator 31 generates electricity using the rotational force of the first shaft 32a. The generator 31 is configured separately from the electric motor 30. In other words, in this embodiment, the generator 31 is not a device that simultaneously performs the functions of an electric motor and a generator, but is a device dedicated to power generation. The generator 31 supplies the generated electricity to the power supply destination 51. The power supply destination 51 is the rotor sail 10, the battery, and electrical equipment within the ship 1.

[0026] The connecting portion 33 is a mechanism on the shaft portion 32 that has a clutch or clutch gear for switching between connecting and disconnecting the electric motor 30 and the generator 31. The clutch is a member that switches between connecting and disconnecting the electric motor 30 and the generator 31. The clutch gear is a member that switches between connecting and disconnecting the electric motor 30 and the generator 31 and also performs reduction by gear. The connecting portion 33 has a first member 33a fixed to the first shaft portion 32a and a second member 33b fixed to the second shaft portion 32b. In the connected state of the connecting portion 33, the first member 33a and the second member 33b are in contact with each other (see Figure 3). In the disconnected state of the connecting portion 33, the second member 33b is spaced apart from the first member 33a in the extending direction of the shaft portion 32 (see Figure 4).

[0027] The propulsion mechanism 100 can switch between an electric propulsion mode and a regenerative power generation mode. In the electric propulsion mode shown in Figure 3, the electric motor 30 generates driving force when connected by the connection part 33. In the regenerative power generation mode shown in Figure 4, the generator 31 generates electricity when disconnected by the connection part 33.

[0028] The operation of the propulsion mechanism 100 in each mode will be described in detail. Here, the electric motor 30 is assumed to rotate at 1200 rpm with a power output of 3300 kW under inverter control. The generator 31 is assumed to rotate at 20 rpm with a power output of 600 kW.

[0029] In the power propulsion mode shown in Figure 3, the electric motor 30 operates by receiving power from the power source 50, causing the second shaft 32b to rotate. At this time, since the first member 33a and the second member 33b are connected to each other at the connection part 33, the rotational force of the second shaft 32b is transmitted to the first shaft 32a. If the connection part 33 has a clutch gear, the rotational force of the second shaft 32b is transmitted to the first shaft 32a in a reduced state (for example, 1200 rpm → 60 rpm). As the first shaft 32a rotates, the propeller 12a of the thruster 12B rotates. This generates thrust from the thruster 12B. At this time, the generator 31 is disconnected from the power source 50 and is not supplying power to the power supply destination 51, and is in an unloaded state. Therefore, in the electric propulsion mode, the generator 31 does not act as resistance to the rotational force transmitted by the electric motor 30 to the thruster 12B.

[0030] In the regenerative power generation mode shown in Figure 4, as the ship 1 moves, the propeller 12a of the thruster 12B rotates due to the water flow. As the propeller 12a rotates, the first shaft 32a rotates. As a result, the generator 31 generates electricity through the rotation of the first shaft 32a and supplies power to the power supply destination 51. At this time, the first member 33a and the second member 33b are separated at the connection part 33. Therefore, the generator 31 and the motor 30 are separated. Consequently, the rotational force of the first shaft 32a is not transmitted to the second shaft 32b, and the motor 30 remains stopped.

[0031] An example of the relationship between each mode of the propulsion mechanism 100 and the operation of the ship 1 will be explained. First, the case in which the ship 1 is propelled solely by the thrust of the rotor sail 10 will be explained. In this case, the propulsion mechanism 100 switches to regenerative power generation mode and separates the members 33a and 33b of the connection part 33. The electric motor 30 is also stopped. As the ship 1 sails, the propeller 12a of the thruster 12B rotates due to the water flow. This causes the generator 31 to generate electricity. In this regenerative power generation mode, the rotor sail 10 is driven by the electricity generated by the generator 31. As a result, the rotor sail 10 can rotate as shown in Figure 2 using the regenerated electricity.

[0032] Next, we will describe the case in which the vessel 1 is propelled by the thrust of the thruster 12B. In this case, the propulsion mechanism 100 switches to electric propulsion mode and connects members 33a and 33b of the connection part 33. The power source 50 supplies power to the electric motor 30 to drive the electric motor 30. As a result, the propeller 12a of the thruster 12B rotates and generates thrust. Here, the electric propulsion mode has a first mode in which power is supplied to the electric motor 30, and a second mode in which power is supplied to the electric motor 30 and the rotor sail 10. In the first mode, the rotor sail 10 is stopped, and the vessel 1 is propelled by the thrust of the thruster 12B. In the second mode, the vessel 1 can be propelled by both the thrust of the thruster 12B and the wind power of the rotor sail 10.

[0033] In the first embodiment, propulsion may be provided by a combination of a thruster 12B powered by an electric motor 30 and a thruster 12A powered by a main engine 16 (see Figure 1). In this case, the thruster 12A powered by the main engine 16 may be equipped with a shaft generator, and the power recovered by the shaft generator may be used as the power source 50. In the second embodiment, in addition to the thrust from the thrusters 12A and 12B in the first embodiment described above, a thrust can be obtained using wind power from the rotor sail 10. Depending on the strength of the wind, a portion of the power used by the thruster 12B as the power source 50 may be supplied to the rotor sail 10.

[0034] Next, the operation and effects of the propulsion mechanism 100 and the ship 1 according to this embodiment will be described.

[0035] First, with reference to Figure 5, the propulsion mechanism 200 of the comparative example will be described. The propulsion mechanism 200 of the comparative example comprises a motor-generator 55, a gear 35, a shaft 32, and a thruster 12B. The motor-generator 55 can perform both electric and power generation. The gear reduces the rotational speed of the motor-generator 55 and transmits it to the thruster 12B. Here, in electric propulsion mode, the motor-generator 55 is driven as a 3300kW electric motor, and in regenerative power generation mode, the motor-generator 55 is driven as a 600kW generator.

[0036] In such a propulsion mechanism 200, the propulsion mechanism 200 is optimized for the high output of the electric propulsion mode and the corresponding high rotational speed. However, in the regenerative power generation mode used at low output and low rotational speed, the settings are not appropriate, resulting in reduced power generation efficiency. Furthermore, in the electric propulsion mode, the motor generator 55 and the thruster 12B are decelerated by the gear 35. For example, with a gear ratio of 20, the motor generator 55 is decelerated from 1200 rpm to 60 rpm to rotate the propeller 12a. In this case, in the regenerative power generation mode, the gear 35 will increase the speed by the same multiplier. For example, the propeller 12a is decelerated from 20 rpm to 400 rpm to generate power with the motor generator 55. In this case, the power generation efficiency in the regenerative power generation mode will inevitably decrease due to the gear efficiency.

[0037] In contrast, the propulsion mechanism 100 according to this embodiment includes an electric motor 30 that generates driving force for the thruster 12B when power is supplied to it, and a generator 31 that is configured separately from the electric motor 30 and generates power through regeneration of the thruster 12B. Furthermore, the propulsion mechanism 100 includes a shaft portion 32 that connects the thruster 12B, the electric motor 30, and the generator 31 as the same power system. This allows the electric motor 30 and the generator 31 to be separate components within the same power system. The connection portion 33 can switch between connecting and disconnecting the electric motor 30 and the generator 31. Therefore, the propulsion mechanism 100 can disconnect the electric motor 30 when the generator 31 is generating power. Accordingly, the electric motor 30 can be set to obtain appropriate output characteristics in the electric propulsion mode, and the generator 31 can be set to obtain appropriate output characteristics in the regenerative power generation mode. As a result, appropriate output characteristics can be obtained in both cases: when generating thrust force by electric power and when generating power.

[0038] The thruster 12B, generator 31, connector 33, and motor 30 may be arranged along the shaft 32 in that order. In this case, in power propulsion mode, the connector 33 is connected and the motor 30 is connected to the thruster 12B. By keeping the generator 31 in an unloaded state, the driving force of the motor 30 can be transmitted to the thruster 12B efficiently. In regenerative power generation mode, the connector 33 is disconnected and the motor 30 is disconnected from the generator 31. As a result, the generator 31 can generate power without being affected by the motor 30.

[0039] The vessel 1 is equipped with the propulsion mechanism 100 described above. This allows the vessel 1 to perform electric propulsion and regeneration effectively.

[0040] The vessel 1 is further equipped with a wind-powered propulsion unit that generates thrust using wind power. In this case, when the wind-powered propulsion unit is generating thrust using wind power, the propulsion mechanism 100 can generate electricity in regenerative power generation mode.

[0041] The wind propulsion unit is the rotor sail 10, and in regenerative power generation mode, the rotor sail 10 may be driven by the electricity generated by the generator 31. This allows the regenerative power obtained by sailing with the rotor sail 10 to be used to drive the rotor sail 10 itself, thereby improving energy efficiency.

[0042] The wind-powered propulsion unit is the rotor sail 10, and the power propulsion mode may have a first mode in which power is supplied to the electric motor 30, and a second mode in which power is supplied to both the electric motor 30 and the rotor sail 10. In the first mode, the rotor sail 10 is stopped, and the ship is propelled by the thrust of the propeller 12B. In this case, the power source 50 can also supply the electric motor 30 with the power that would otherwise be supplied to the rotor sail 10. Therefore, the output of the electric motor 30 can be increased. In the second mode, the ship 1 can be propelled by both the thrust of the propeller 12B and the wind-powered thrust of the rotor sail 10. Therefore, the ship 1 can be propelled while taking advantage of the benefits of both types of propulsion.

[0043] The present invention is not limited to the embodiments described above.

[0044] The structure of the hull 11 is not limited to that shown in Figure 1 and may be modified as appropriate depending on the intended use. For example, the shape and arrangement of the living quarters are not limited to those described above.

[0045] In the above-described embodiment, four rotor sails 10 were provided. However, the number and position of the rotor sails are not particularly limited.

[0046] In the above-described embodiment, a rotor sail was used as the wind propulsion unit. However, any type of wind propulsion unit may be used, such as a rigid wing sail or a kite.

[0047] The configuration of the propulsion mechanism is not limited to that shown in Figure 3. For example, the thruster 12B, electric motor 30, connector 33, and generator 31 may be arranged in that order from bottom to top along the shaft 32. [Explanation of Symbols]

[0048] 1...Ship, 10...Rotor sail (wind propulsion unit), 12B...Propulsion unit, 30...Electric motor, 31...Generator, 32...Shaft, 33...Connecting unit, 100...Propulsion mechanism.

Claims

1. A thruster that generates propulsion, An electric motor that generates the driving force of the thruster by being supplied with power, A generator, configured separately from the aforementioned electric motor, generates electricity through the regeneration of the thruster, A shaft portion connecting the thruster, the electric motor, and the generator as the same power system, The shaft portion includes a connecting portion having a clutch or clutch gear for switching between connecting and disconnecting the electric motor and the generator, A propulsion mechanism that switches between an electric propulsion mode in which the electric motor generates driving force and a regenerative power generation mode in which the generator generates electricity.

2. The propulsion mechanism according to claim 1, wherein the thruster, the generator, the connecting part, and the electric motor are arranged in that order along the shaft portion.

3. A ship equipped with the propulsion mechanism described in claim 1.

4. The vessel according to claim 3, further comprising a wind-powered propulsion unit that generates thrust by wind power.

5. The aforementioned wind propulsion unit is a rotor sail, The vessel according to claim 4, wherein in the regenerative power generation mode, the rotor sail is driven by the power generated by the generator.

6. The aforementioned wind propulsion unit is a rotor sail, The vessel according to claim 4, wherein the electric propulsion mode comprises a first mode for supplying power to the electric motor and a second mode for supplying power to the electric motor and the rotor sail.

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