Vessel propulsion system

Abstract

To bring down running cost when using a vessel provided with a vessel propeller with an internal combustion engine as a power source and a vessel propeller with a motor as a power source.SOLUTION: A vessel propulsion system 1 includes an outboard engine 2 generating propulsion force of a vessel by power of an engine 3, a fly wheel magnet 11 for generating power by rotation of a crank shaft 4 of the engine 3, an invertor 12 for carrying out rectifying action for rectifying electric power generated by the fly wheel magnet 11, a capacitor 14 provided on the outboard engine 2, and an electric propeller 17 generating propulsion force for the vessel by power of a motor 18. The capacitor 14 accumulates power generated by the fly wheel magnet 11 and rectified by rectifying action of the inverter 12, and the motor 18 is driven by the power accumulated in the capacitor 14.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a ship propulsion system for propelling a ship.

Background Art

[0002] A ship propulsion machine powered by an internal combustion engine and a ship propulsion machine powered by a motor (electric motor) are provided on a single ship. For long-distance movement, the ship propulsion machine powered by the internal combustion engine is used, and for short-distance movement, the ship propulsion machine powered by the motor may be used. For example, when bass fishing on a large lake, an outboard motor powered by an internal combustion engine and an outboard motor powered by a motor (which may be called, for example, an electric motor or a trolling motor) are attached to a bass boat. To quickly move to a point near the fishing point, the outboard motor powered by the internal combustion engine is used, and to move from that point to the fishing point, the outboard motor powered by the motor may be used to move slowly and quietly.

[0003] Japanese Unexamined Patent Application Publication No. 2022-68615 (Patent Document 1) describes a ship provided with a ship propulsion machine powered by an internal combustion engine and a ship propulsion machine powered by a motor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in a marine propulsion unit using an internal combustion engine as a power source, a battery is mainly used to supply power to auxiliary machines. Auxiliary machines are electrical components such as a starter for starting the internal combustion engine and sensors for detecting the operating state of the internal combustion engine. Conventionally, a lead-acid battery has been used as the battery for supplying power to auxiliary machines. Also, lead-acid batteries include a starter battery designed to be able to instantaneously supply a large current to the starter at the start of the internal combustion engine, and a deep cycle battery designed to adapt to repeated charge and discharge. A starter battery is used as the battery for supplying power to auxiliary machines.

[0006] Also, in a marine propulsion unit using a motor as a power source, a battery is mainly used to supply power to the motor. Conventionally, a lead-acid battery has been used as the battery for supplying power to the motor. Also, a deep cycle battery is used as the battery for supplying power to the motor.

[0007] Conventionally, when a marine propulsion unit using an internal combustion engine as a power source and a marine propulsion unit using a motor as a power source are provided on a single ship and navigation is performed using these marine propulsion units, two types of lead-acid batteries, a starter battery and a deep cycle battery, are installed on the ship. The marine propulsion unit using the internal combustion engine as a power source is supplied with power from the starter battery, and the marine propulsion unit using the motor as a power source is supplied with power from the deep cycle battery. In this case, since the lead-acid battery has a short lifespan, in order to continue using the ship, the user has to frequently replace the above two types of lead-acid batteries. As a result, when using a ship equipped with a marine propulsion unit using an internal combustion engine as a power source and a marine propulsion unit using a motor as a power source, the running cost becomes high.

[0008] The present invention has been made in view of problems such as those described above, and an object of the present invention is to provide a marine propulsion system capable of reducing the running cost when using a ship equipped with a marine propulsion unit using an internal combustion engine as a power source and a marine propulsion unit using a motor as a power source.

Means for Solving the Problems

[0009] To solve the above problems, the present invention provides a ship propulsion system for propelling a ship, comprising: a first propulsion machine having an internal combustion engine and generating a propulsion force of the ship by the power of the internal combustion engine; a generator that generates electricity by the rotation of a crankshaft of the internal combustion engine; a power converter that converts the alternating current power generated by the generator into direct current power; a capacitor provided in the first propulsion machine; and a second propulsion machine having a motor and generating a propulsion force of the ship by the power of the motor. The capacitor stores the direct current power generated by the generator and converted by the power converter, and the motor is driven by the power stored in the capacitor.

Advantages of the Invention

[0010] According to the present invention, when using a ship provided with a ship propulsion machine powered by an internal combustion engine and a ship propulsion machine powered by a motor, the running cost can be reduced.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0012] The ship propulsion system according to an embodiment of the present invention includes a first propulsion machine having an internal combustion engine and generating a propulsion force of the ship by the power of the internal combustion engine, a generator that generates electricity by the rotation of the crankshaft of the internal combustion engine, a power converter that converts the generated AC power into DC power, a capacitor provided in the first propulsion machine, and a second propulsion machine having a motor and generating a propulsion force of the ship by the power of the motor. Further, in the ship propulsion system of the present embodiment, the capacitor stores the DC power generated by the generator and converted by the power converter, and the motor is driven by the power stored in the capacitor.

[0013] In the present embodiment, since the motor of the second propulsion machine can be driven by the power stored in the capacitor, a deep cycle battery is not required when driving the motor of the second propulsion machine. Further, the capacitor has a longer lifespan than a lead-acid battery such as a deep cycle battery. Therefore, the replacement cycle of the capacitor can be made longer than that of the lead-acid battery. Thus, according to the present embodiment, when using a ship provided with a ship propulsion machine powered by an internal combustion engine and a ship propulsion machine powered by a motor, the running cost can be reduced.

Example

[0014] FIG. 1 is a circuit diagram showing a ship propulsion system 1 according to an embodiment of the present invention. FIG. 2 is an external view showing a ship 40 to which the ship propulsion system 1 is applied.

[0015] (Configuration of Ship Propulsion System) The ship propulsion system 1 is a system for propelling a ship and is provided on the ship. As shown in FIG. 1, the ship propulsion system 1 includes an outboard motor 2, a flywheel magnet 11, an inverter 12, an inverter control unit 13, a capacitor 14, a relay 15, a relay control unit 16, an electric propulsion machine 17, a bidirectional DC (Direct Current) / DC converter 25, a converter control unit 26, a battery 27, electrical components 28, and a system control unit 29.

[0016] The outboard motor 2 is a device that generates the propulsion force of the ship 40 by the power of the engine 3 as an internal combustion engine. As shown in FIG. 2, the outboard motor 2 is provided at the stern of the ship 40. The outboard motor 2 includes an engine 3 provided at the upper part of the outboard motor 2, a drive shaft 5 that transmits the power of the engine 3 to the lower part of the outboard motor 2, a propeller 6 provided at the lower part of the outboard motor 2 that converts the power of the engine 3 into the propulsion force of the ship 40, a propeller shaft 7 that supports the propeller 6, a gear mechanism 8 that transmits the power of the engine 3 transmitted through the drive shaft 5 to the propeller shaft 7, and a clamp bracket 9 that fixes the outboard motor 2 to the stern of the ship 40. Note that the outboard motor 2 is a specific example of the "first propulsion machine".

[0017] The flywheel magnet 11 is a device that combines the functions of a generator and a starter, and is called an ISG (Integrated Starter Generator). The flywheel magnet 11 is provided inside the outboard motor 2. As shown in FIG. 1, the rotor of the flywheel magnet 11 is connected to the crankshaft 4 of the engine 3. In this embodiment, when the engine 3 is started, the flywheel magnet 11 operates as a starter motor by the three-phase drive current supplied from the inverter 12, rotates the crankshaft 4, and after the engine 3 is started, it generates electricity by the rotation of the crankshaft 4 that rotates by the operation of the engine 3, and generates three-phase alternating current power. Note that the flywheel magnet 11 is a specific example of the "generator".

[0018] The inverter 12 is a device that combines the function of generating a three-phase drive current for operating the flywheel magnet 11 as a starter motor and supplying the generated drive current to the flywheel magnet 11, and the rectifying function of converting the three-phase alternating current power generated by the flywheel magnet 11 into direct current power. The inverter 12 is provided inside the outboard motor 2. The inverter 12 is electrically connected to the flywheel magnet 11 as shown in FIG. 1. Note that the inverter 12 is a specific example of the "power converter".

[0019] The inverter control unit 13 is a device that controls the inverter 12 and is provided, for example, inside the inverter 12. The inverter control unit 13 switches the operation of the inverter 12 between (a) an inverter operation of generating a three-phase drive current for operating the flywheel magnet 11 as a starter motor and supplying the generated drive current to the flywheel magnet 11, and (b) a rectification operation of converting the three-phase AC power generated by the flywheel magnet 11 into DC power. Specifically, the inverter control unit 13 controls the inverter 12 to perform the inverter operation when starting the engine 3 based on a command signal from the system control unit 29, and controls the inverter 12 to perform the rectification operation after the engine 3 has started. Note that the inverter control unit 13 and the system control unit 29 are specific examples of the "power conversion control unit".

[0020] The capacitor 14 is electrically connected to the inverter 12, the electric propulsion motor 17, and the bidirectional DC / DC converter 25 as shown in FIG. 1. The capacitor 14 is provided inside the outboard motor 2. For example, the capacitor 14 is arranged at the upper part of the outboard motor 2. The capacitor 14 stores the power generated by the flywheel magnet 11 and rectified by the rectification operation of the inverter 12. The charging of the capacitor 14 is basically performed using the power generated by the flywheel magnet 11, but it is also possible to charge the capacitor 14 using the power stored in the battery 27. Further, the capacitor 14 functions as a power source for the electric propulsion motor 17. Also, the capacitor 14 functions as a power source for the inverter 12 when the inverter 12 generates a drive current for operating the flywheel magnet 11 as a starter motor. Further, the capacitor 14 can also function as a power source for charging the battery 27. As the capacitor 14, for example, a lithium-ion capacitor or an electric double layer capacitor can be used. In this embodiment, the rated voltage of the capacitor 14 is approximately 48V, for example.

[0021] Relay 15 has a function of preventing the electricity stored in capacitor 14 from discharging while the ship propulsion system 1 is stopped. The relay control unit 16 controls the on / off of relay 15 based on a command signal from the system control unit 29. Relay 15 and the relay control unit 16 are provided inside the outboard motor 2. When the ship propulsion system 1 stops, relay 15 turns off, and one terminal of capacitor 14 is disconnected from the inverter 12, the electric propulsion motor 17, etc. Thereby, the discharge of the electricity stored in capacitor 14 is prevented. On the other hand, when the ship propulsion system 1 starts, relay 15 turns on, and one terminal of capacitor 14 is connected to the inverter 12, the electric propulsion motor 17, etc. Thereby, the charging of capacitor 14 or the supply of power from capacitor 14 to the electric propulsion motor 17, etc. becomes possible.

[0022] The electric propulsion motor 17 is a device that generates the propulsion force of the ship 40 by the power of the motor 18. In this embodiment, the electric propulsion motor 17 is, for example, what is called an electric motor or a trolling motor. As shown in FIG. 2, the electric propulsion motor 17 is provided at a portion on the bow side of the ship 40. The electric propulsion motor 17 includes a motor 18, a propeller 20 attached to the output shaft 19 of the motor 18, a motor housing 21 that houses the motor 18, a support shaft 22 that supports the motor housing 21 so as to sink it into the water, and a mounting bracket 23 that attaches the support shaft 22 to the ship 40. The motor 18 is driven by the electric power stored in the capacitor 14 or the electric power generated by the flywheel magnet 11 and rectified by the rectifying operation of the inverter 12. In this embodiment, the appropriate voltage of the electric propulsion motor 17 is, for example, approximately 48V. Note that the electric propulsion motor 17 is a specific example of the "second propulsion motor".

[0023] The bidirectional DC / DC converter 25 is a device that combines the function of boosting the voltage output from the battery 27 and applying it to the capacitor 14, and the function of stepping down the voltage output from the inverter 12 or the capacitor 14 that is performing a rectifying operation and applying it to the battery 27. The bidirectional DC / DC converter 25 is provided in the outboard motor 2. The bidirectional DC / DC converter 25 is electrically connected to the inverter 12, the capacitor 14, the battery 27, etc. as shown in FIG. 1. In this embodiment, the bidirectional DC / DC converter 25 can boost a voltage of, for example, 12V output from the battery 27 to 48V, and can also step down a voltage of, for example, 48V output from the inverter 12 or the capacitor 14 that is performing a rectifying operation to 12V. Note that the bidirectional DC / DC converter 25 is a specific example of a "voltage converter".

[0024] The converter control unit 26 is a device that controls the bidirectional DC / DC converter 25, and is provided, for example, inside the bidirectional DC / DC converter 25. The converter control unit 26 switches the operation of the bidirectional DC / DC converter 25 between (a) a boosting operation of boosting the voltage output from the battery 27 and applying it to the capacitor 14, and (b) a bucking operation of stepping down the voltage output from the inverter 12 or the capacitor 14 that is performing a rectifying operation and applying it to the battery 27. Specifically, when the converter control unit 26 charges the capacitor 14 with the power stored in the battery 27 based on a command signal from the system control unit 29, it controls the bidirectional DC / DC converter 25 to perform a boosting operation, and when charging the battery 27 with the power generated by the flywheel magnet 11 or the power stored in the capacitor 14, it controls the bidirectional DC / DC converter 25 to perform a bucking operation. Further, the converter control unit 26 can stop the bidirectional DC / DC converter 25 based on a command signal from the system control unit 29 during the operation of the marine propulsion system 1. Note that the converter control unit 26 and the system control unit 29 are specific examples of a "voltage conversion control unit".

[0025] The battery 27 mainly functions as a power source for the electrical components 28 provided in the outboard motor 2. The electrical components 28 include, for example, sensors for detecting the operating state of the engine 3. Also, the battery 27 also functions as a power source for the inverter control unit 13, the relay control unit 16, the converter control unit 26, and the system control unit 29. Further, the battery 27 can also function as a power source for charging the capacitor 14. Also, the charging of the battery 27 is basically performed using the electric power generated by the flywheel magnet 11, but the battery 27 can also be charged using the electric power stored in the capacitor 14. In this embodiment, the battery 27 is, for example, a lead-acid battery with a nominal voltage of 12V and is also a starter battery. Also, the battery 27 is provided on the hull of the ship 40.

[0026] The system control unit 29 is a device that controls the ship propulsion system 1 and is composed of, for example, an ECM (Electronic Control Module). The system control unit 29 detects the state of the power switch 30 (whether the power switch 30 is on or off), the state of the engine 3 (whether the engine 3 is stopped or running, etc.), the output voltage of the capacitor 14, and the output voltage of the battery 27. In FIG. 1, the illustration of the circuit for detecting the output voltage of the capacitor 14 and the output voltage of the battery 27 is omitted. Also, the system control unit 29 controls the relay control unit 16, the inverter control unit 13, the converter control unit 26, etc.

[0027] (Operation of the ship propulsion system) [Operation regarding power on / off of the ship propulsion system] The ship propulsion system 1 starts operating when the power switch 30 is turned on and stops after the power switch 30 is turned off. When the power switch 30 is turned on during the stop of the ship propulsion system 1, the system control unit 29 outputs a command signal to the relay control unit 16 to switch the relay 15 from off to on. Based on this command signal, the relay control unit 16 switches the relay 15 from off to on. When the relay 15 is turned on, one terminal of the capacitor 14 is connected to the inverter 12, the electric propulsion motor 17, etc. Thereby, charging of the capacitor 14 or supply of power from the capacitor 14 to the electric propulsion motor 17, etc. becomes possible. Also, during the operation of the ship propulsion system 1, when the power switch 30 is turned off, the system control unit 29 outputs a command signal to the relay control unit 16 to switch the relay 15 from on to off. Based on this command signal, the relay control unit 16 switches the relay 15 from on to off. When the relay 15 is turned off, one terminal of the capacitor 14 is disconnected from the inverter 12, the electric propulsion motor 17, etc. Thereby, discharge of the electricity stored in the capacitor 14 is prevented.

[0028] [Operation regarding engine start] During the operation of the ship propulsion system 1, when the engine start switch (not shown) is turned on, the system control unit 29 starts the engine 3. When starting the engine 3, the system control unit 29 first determines whether the voltage of the capacitor 14 is equal to or higher than a predetermined capacitor full charge reference voltage. The capacitor full charge reference voltage is, for example, 48V.

[0029] When the voltage of the capacitor 14 is equal to or higher than the capacitor full charge reference voltage, the system control unit 29 immediately starts the engine 3. Specifically, the system control unit 29 outputs a command signal to switch the operation of the inverter 12 to the inverter operation and a command signal to drive the flywheel magnet 11 as a starter motor to the inverter control unit 13. The inverter control unit 13 controls the inverter 12 according to these command signals. Then, by the control of the inverter control unit 13, the inverter 12 generates a drive current by the electric power stored in the capacitor 14 and supplies the drive current to the flywheel magnet 11. As a result, the flywheel magnet 11 operates as a starter motor, the crankshaft 4 rotates by the power of the flywheel magnet 11, and the engine 3 starts.

[0030] On the one hand, when starting the engine 3, if the voltage of the capacitor 14 is less than the capacitor full charge reference voltage, the system control unit 29 charges the capacitor 14 using the power stored in the battery 27 and then starts the engine 3. Specifically, the system control unit 29 outputs a command signal to the converter control unit 26 to switch the operation of the bidirectional DC / DC converter 25 to the boost operation. The converter control unit 26 controls the bidirectional DC / DC converter 25 according to this command signal. Then, under the control of this converter control unit 26, the bidirectional DC / DC converter 25 boosts the voltage output from the battery 27 and applies it to the capacitor 14. As a result, the capacitor 14 is charged by the power stored in the battery 27. When the capacitor 14 is charged and the output voltage of the capacitor 14 becomes equal to or higher than the capacitor full charge reference voltage, the system control unit 29 outputs a command signal to the inverter control unit 13 to switch the operation of the inverter 12 to the inverter operation, and a command signal to drive the flywheel magnet 11 as a starter motor. The inverter control unit 13 controls the inverter 12 according to these command signals, and the inverter 12 generates a drive current using the power stored in the capacitor 14 and supplies the drive current to the flywheel magnet 11. As a result, the crankshaft 4 rotates by the power of the flywheel magnet 11, and the engine 3 starts.

[0031] [Operation after engine start] After the ship propulsion system 1 operates and the engine 3 starts, the system control unit 29 outputs a command signal to the inverter control unit 13 to switch the operation of the inverter 12 to the rectification operation. The inverter control unit 13 controls the inverter 12 according to this command signal. As a result, after the engine 3 starts, the inverter 12 rectifies the power generated by the flywheel magnet 11. The power rectified by the inverter 12 is supplied to the capacitor 14, the bidirectional DC / DC converter 25, and the electric propulsion motor 17.

[0032] After the ship propulsion system 1 starts operating and the engine 3 starts, the system control unit 29 outputs a command signal to the converter control unit 26 to switch the operation of the bidirectional DC / DC converter 25 to the step-down operation. The converter control unit 26 controls the bidirectional DC / DC converter 25 according to this command signal. Thereby, after the engine 3 starts, the bidirectional DC / DC converter 25 steps down the voltage of the electric power generated by the flywheel magnet 11, rectified by the rectifying operation of the inverter 12, and supplied to the bidirectional DC / DC converter 25. The electric power stepped down by the bidirectional DC / DC converter 25 is supplied to the electrical components 28 and the battery 27.

[0033] [Operations related to driving of the electric propulsion motor] While the ship propulsion system 1 is operating and the engine 3 is stopped, when an operation to drive the motor 18 of the electric propulsion motor 17 is performed, the motor 18 of the electric propulsion motor 17 is driven using the electric power stored in the capacitor 14. Also, while the ship propulsion system 1 is operating and the engine 3 is driving, when an operation to drive the motor 18 of the electric propulsion motor 17 is performed, the motor 18 of the electric propulsion motor 17 is driven using the electric power generated by the flywheel magnet 11 and rectified by the rectifying operation of the inverter 12.

[0034] [Operations related to charging of the capacitor] While the ship propulsion system 1 is operating and the engine 3 is driving (after the engine 3 starts), the capacitor 14 is charged by the electric power generated by the flywheel magnet 11 and rectified by the rectifying operation of the inverter 12.

[0035] Also, while the ship propulsion system 1 is operating and the engine 3 is stopped, the capacitor 14 can be charged by the electric power stored in the battery 27. For example, while the ship propulsion system 1 is operating and the engine 3 is stopped, when a user operates operating means (not shown) to input an instruction to the system control unit 29 to charge the capacitor 14 with the electric power stored in the battery 27, the system control unit 29 outputs a command signal to the converter control unit 26 to switch the operation of the bidirectional DC / DC converter 25 to a boosting operation. The converter control unit 26 controls the bidirectional DC / DC converter 25 according to this command signal. Then, by the control of this converter control unit 26, the bidirectional DC / DC converter 25 boosts the voltage output from the battery 27 and applies it to the capacitor 14. Thereby, the capacitor 14 is charged by the electric power stored in the battery 27.

[0036] [Operation regarding charging of battery] While the ship propulsion system 1 is operating and the engine 3 is driving, the battery 27 is charged by the electric power generated by the flywheel magnet 11, rectified by the rectifying operation of the inverter 12, and stepped down by the bidirectional DC / DC converter.

[0037] Also, while the ship propulsion system 1 is operating and the engine 3 is stopped, the battery 27 can be charged by the electric power stored in the capacitor 14. For example, while the ship propulsion system 1 is operating and the engine 3 is stopped, when a user operates operating means (not shown) to input an instruction to charge the battery 27 with the electric power stored in the capacitor 14 to the system control unit 29, the system control unit 29 outputs a command signal to the converter control unit 26 to switch the operation of the bidirectional DC / DC converter 25 to a step-down operation. The converter control unit 26 controls the bidirectional DC / DC converter 25 according to this command signal. Then, by the control of this converter control unit 26, the bidirectional DC / DC converter 25 steps down the voltage output from the capacitor 14 and applies it to the battery 27. Thereby, the battery 27 is charged by the electric power stored in the capacitor 14.

[0038] Also, while the system control unit 29 is charging the battery 27 with the electric power generated by the flywheel magnet 11 during the operation of the ship propulsion system 1 and the driving of the engine 3, when the output voltage of the battery 27 becomes equal to or higher than a predetermined battery full charge reference voltage, the system control unit 29 outputs a command signal to the converter control unit 26 to stop the bidirectional DC / DC converter 25. Thereby, the electric power generated by the flywheel magnet 11 and rectified by the rectifying operation of the inverter 12 is no longer supplied to the battery 27. Thereafter, during the operation of the ship propulsion system 1, when the output voltage of the battery 27 becomes lower than the battery full charge reference voltage, the system control unit 29 outputs a command signal to the converter control unit 26 to operate the bidirectional DC / DC converter 25 and operates the bidirectional DC / DC converter 25. The battery full charge reference voltage is, for example, 12V. Note that the battery full charge reference voltage is a specific example of the "full charge reference voltage".

[0039] As described above, the marine propulsion system 1 of the embodiment of the present invention includes an outboard motor 2 that generates the propulsion force of a ship by the power of an engine 3, a flywheel magnet 11 that generates electricity by the rotation of a crankshaft 4 of the engine 3, an inverter 12 having a function of rectifying the AC power generated by the flywheel magnet 11, a capacitor 14 that stores the power generated by the flywheel magnet 11 and rectified by the inverter 12, and an electric propulsion unit 17 that generates the propulsion force of the ship by the power of a motor 18. The electric propulsion unit 17 is driven by the power stored in the capacitor 14. In the marine propulsion system 1 of the present embodiment, since the electric propulsion unit 17 can be driven by the power stored in the capacitor 14, a deep cycle battery for driving the electric propulsion unit 17 becomes unnecessary. In addition, the capacitor 14 has a longer lifespan than a lead-acid battery such as a deep cycle battery. Therefore, the replacement cycle of the capacitor 14 can be made longer than the replacement cycle of the lead-acid battery. Therefore, according to the marine propulsion system 1 of the present embodiment, when using a ship 40 provided with the outboard motor 2 and the electric propulsion unit 17, the running cost can be reduced. In addition, since it is not necessary to mount a deep cycle battery for driving the electric propulsion unit 17 on the ship, it is possible to prevent the space inside the ship from being narrowed due to the mounting of the deep cycle battery on the ship. Further, since the weight of the capacitor 14 can be made lighter than the weight of the deep cycle battery required to drive the electric propulsion unit 17, the weight of the ship 40 during navigation can be reduced, and the running performance of the ship 40 can be improved. In addition, since the capacitor 14 can be charged at a high speed compared to a lead-acid battery, the power for driving the electric propulsion unit 17 can be quickly secured.

[0040] In addition, the ship propulsion system 1 of this embodiment includes a battery 27 and a bidirectional DC / DC converter 25 that has a function of boosting the voltage output from the battery 27 and applying it to the capacitor 14. With this configuration, the capacitor 14 can be charged by the voltage output from the battery 27 and boosted by the bidirectional DC / DC converter 25. Therefore, when starting the engine 3 with the power stored in the capacitor 14, if the power stored in the capacitor 14 is insufficient, the engine 3 can be started by charging the capacitor 14 with the power stored in the battery 27. Also, when driving the electric propulsion motor 17 with the power stored in the capacitor 14, if the power stored in the capacitor 14 is insufficient, the electric propulsion motor 17 can be driven by charging the capacitor 14 with the power stored in the battery 27.

[0041] In addition, in the ship propulsion system 1 of this embodiment, the bidirectional DC / DC converter 25 has a function of stepping down the voltage output from the capacitor 14 and applying it to the battery 27. With this configuration, the battery 27 can be charged by the voltage output from the capacitor 14 and stepped down by the bidirectional DC / DC converter 25.

[0042] In addition, the ship propulsion system 1 of this embodiment includes a bidirectional DC / DC converter 25, a converter control unit 26, and a system control unit 29. The converter control unit 26 and the system control unit 29 switch the operation of the bidirectional DC / DC converter 25 between a boosting operation and a bucking operation. Thereby, compared with the case of providing a boosting DC / DC converter and a bucking DC / DC converter, the circuit configuration in the ship propulsion system 1 can be simplified.

[0043] Further, in the ship propulsion system 1 of this embodiment, the converter control unit 26 and the system control unit 29 stop the bidirectional DC / DC converter 25 when the output voltage of the battery 27 is equal to or higher than the battery full charge reference voltage. Thereby, the charging operation of the battery 27 after being fully charged can be stopped with a simple configuration.

[0044] Further, the ship propulsion system 1 of this embodiment includes an inverter 12 having a function of generating a drive current for operating the flywheel magnet 11 as a starter motor and supplying the drive current to the flywheel magnet 11, a function of rectifying the electric power generated by the flywheel magnet 11, an inverter control unit 13, and a system control unit 29. Further, the inverter control unit 13 and the system control unit 29 control the inverter 12 to perform an inverter operation at the start of the engine 3, and control the inverter 12 to perform a rectifying operation after the engine 3 has started. Further, the flywheel magnet 11 rotates the crankshaft 4 of the engine 3 by operating as a starter motor by the drive current supplied from the inverter 12 at the start of the engine 3, and generates electric power by the rotation of the crankshaft 4 rotated by the operation of the engine 3 after the engine 3 has started. Further, the inverter 12 generates a drive current by the electric power stored in the capacitor 14 during the inverter operation. According to the ship propulsion system 1 having such a configuration, since the engine 3 can be started by the flywheel magnet 11, it is not necessary to provide a dedicated engine starting device in the outboard motor 2, and the outboard motor 2 can be downsized or lightened.

[0045] In the above-described embodiment, the case where the electric propulsion unit 17 separate from the outboard motor 2 is provided at the bow side portion of the ship 40 has been taken as an example. However, the present invention is not limited to this. As in the ship propulsion system 51 shown in FIG. 3, the electric propulsion unit 61 may be incorporated into the outboard motor 52. FIG. 4 shows an example of the outboard motor 52 in which the electric propulsion unit 61 is incorporated. In FIG. 4, an engine 53 and a motor 62 are provided at the upper part of the outboard motor 52. Further, the outboard motor 52 is provided with a first drive shaft 56 and a first gear mechanism 57 for transmitting the power of the engine 53 to the propeller shaft 55. Further, the outboard motor 52 is provided with a second drive shaft 63 and a second gear mechanism 64 for transmitting the power of the motor 62 to the propeller shaft 55. The first gear mechanism 57 has a clutch mechanism capable of switching between a state where the first drive shaft 56 and the propeller shaft 55 are connected and a state where the first drive shaft 56 and the propeller shaft 55 are disconnected. The second gear mechanism 64 has a clutch mechanism capable of switching between a state where the second drive shaft 63 and the propeller shaft 55 are connected and a state where the second drive shaft 63 and the propeller shaft 55 are disconnected. The outboard motor 52 can perform an operation of rotating the propeller 54 only with the power of the engine 53, an operation of rotating the propeller 54 only with the power of the motor 62, and an operation of rotating the propeller 54 with the power of both the engine 53 and the motor 62, and these operations can be switched by controlling the clutch mechanism of the first gear mechanism 57 and the clutch mechanism of the second gear mechanism 64.

[0046] In the ship propulsion system 1 of the above embodiment, the case where the inverter 12 capable of performing the inverter operation and the rectification operation is provided has been described as an example. However, instead of this, an inverter that performs only the inverter operation and a rectifier that performs the rectification operation may be provided. Also, in the ship propulsion system 1 of the above embodiment, the case where the bidirectional DC / DC converter 25 capable of performing the boosting operation and the bucking operation is provided has been described as an example. However, instead of this, a DC / DC converter that performs only the boosting operation and a DC / DC converter that performs only the bucking operation may be provided. Further, the battery 27 is not limited to a lead-acid battery, and a lithium-ion battery may also be used.

[0047] Also, in the above embodiment, an outboard motor has been described as an example of the first propulsion device having an internal combustion engine. However, a ship propulsion device other than an outboard motor can be used as the first propulsion device. Further, the present invention can be applied to various ships.

[0048] Further, the present invention can be appropriately modified within the scope not contrary to the gist or idea of the invention that can be read from the claims and the entire specification, and a ship propulsion system involving such a modification is also included in the technical idea of the present invention.

Explanation of Reference Numerals

[0049] 1, 51 Ship propulsion system 2, 52 Outboard motor (first propulsion device) 3, 53 Engine (internal combustion engine) 11 Flywheel magnet (generator) 12 Inverter (power converter) 13 Inverter control unit (power conversion control unit) 14 Capacitor 17, 61 Electric propulsion device (second propulsion device) 18, 62 Motor 25 Bidirectional DC / DC converter (voltage converter) 26 Converter control unit (voltage conversion control unit) 27 Battery 28 Electrical components 29 System control unit (power conversion control unit, voltage conversion control unit) 40 Ships

Claims

1. A ship propulsion system for propelling a ship, comprising: a first propulsion machine having an internal combustion engine and generating a propulsion force of the ship by the power of the internal combustion engine; a generator that generates electric power by the rotation of the crankshaft of the internal combustion engine; a power converter that converts the alternating current power generated by the generator into direct current power; a capacitor provided in the first propulsion machine; and a second propulsion machine having a motor and generating a propulsion force of the ship by the power of the motor. The capacitor stores the direct current power generated by the generator and converted by the power converter, and the motor is driven by the power stored in the capacitor. A ship propulsion system characterized by that.

2. a battery used as a power source for electrical components of the first propulsion machine; and a voltage converter that boosts the voltage output from the battery and applies it to the capacitor. The ship propulsion system according to claim 1, wherein the capacitor is charged by the voltage output from the battery and boosted by the voltage converter.

3. a battery used as a power source for electrical components of the first propulsion machine; and a voltage converter that steps down the voltage output from the capacitor and applies it to the battery. The ship propulsion system according to claim 1, wherein the battery is charged by the voltage output from the capacitor and stepped down by the voltage converter.

4. a battery used as a power source for electrical components of the first propulsion machine; and a voltage converter capable of performing a boosting operation of boosting the voltage output from the battery and applying it to the capacitor, and a bucking operation of stepping down the voltage output from the capacitor and applying it to the battery. A voltage conversion control unit that switches the operation of the voltage converter between the boost operation and the buck operation. The voltage conversion control unit switches the operation of the voltage converter to the boost operation when charging the capacitor with the power stored in the battery, and switches the operation of the voltage converter to the buck operation when charging the battery with the power stored in the capacitor. The marine propulsion system according to claim 1, characterized in that.

5. The voltage conversion control unit stops the operation of the voltage converter when the voltage of the battery is equal to or higher than a predetermined full charge reference voltage. The marine propulsion system according to claim 4, characterized in that.

6. A power conversion control unit for controlling the power converter is provided. The power converter can perform an inverter operation of generating a drive current for operating the generator as a motor and supplying the generated drive current to the generator, and a rectification operation of converting the AC power generated by the generator into DC power. The power conversion control unit controls the power converter to perform the inverter operation at the start of the internal combustion engine, and controls the power converter to perform the rectification operation after the start of the internal combustion engine. The generator rotates the crankshaft by operating as a motor by the drive current supplied from the power converter at the start of the internal combustion engine, and generates electricity by the rotation of the crankshaft rotated by the operation of the internal combustion engine after the start of the internal combustion engine. The power converter generates the drive current by the power stored in the capacitor during the inverter operation. The marine propulsion system according to claim 1, characterized in that.

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