Jet propulsion watercraft

Abstract

A jet propulsion watercraft includes a watercraft body; a battery; an electric propulsion device that includes an electric motor driven by electricity supplied from the battery and applies a propulsive force to the watercraft body; a jet propulsion device that generates a jet water flow by a power source different from the electric motor and applies a propulsive force to the watercraft body by the jet water flow; and a control device that controls the electric propulsion device and the jet propulsion device. The control device controls the electric propulsion device on the basis of a remaining charge amount of the battery.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to and the benefit of Japanese Patent Application No. 2025-016546, filed on Feb. 4, 2025, the entire disclosure of which is incorporated herein by reference.FIELD OF INVENTION

[0002] The present disclosure relates to a jet propulsion watercraft.BACKGROUND ART

[0003] As a type of a jet propulsion watercraft, a jet propulsion watercraft recited in US 2013 / 0102206 A is known.

[0004] When a remaining charge amount of a battery mounted on a watercraft body of a jet propulsion watercraft decreases, it becomes difficult to operate an electric component mounted on the watercraft body and supplied with power from the battery.SUMMARY OF THE INVENTION

[0005] The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a jet propulsion watercraft enabling suppression of an excessive decrease in a remaining charge amount of a battery mounted on a watercraft body.

[0006] A jet propulsion watercraft according to an aspect of the present disclosure includes: a watercraft body; a battery; an electric propulsion device including an electric motor driven by electricity supplied from the battery, the electric propulsion device applying a propulsive force to the watercraft body; a jet propulsion device that generates a jet water flow by a power source different from the electric motor and applies a propulsive force to the watercraft body by the jet water flow; and a control device that controls the electric propulsion device and the jet propulsion device, in which the control device controls the electric propulsion device on the basis of a remaining charge amount of the battery.

[0007] A jet propulsion watercraft according to another aspect of the present disclosure includes: a watercraft body; a battery; an electric propulsion device including an electric motor driven by electricity supplied from the battery, the electric propulsion device applying a propulsive force to the watercraft body; a jet propulsion device including an engine and a jet water flow generator driven by the engine to generate a jet water flow, the jet propulsion device applying a propulsive force to the watercraft body by the jet water flow; a generator that is driven by the engine to generate power and charge the battery; an electric starter that is supplied with power by the battery to start the engine; and a control device that controls the electric propulsion device and the jet propulsion device, in which the control device controls the engine to increase a power generation amount of the generator when a remaining charge amount of the battery is less than a predetermined lower limit determination amount.

[0008] A jet propulsion watercraft according to still another aspect of the present disclosure includes a watercraft body; a battery; an electric propulsion device including an electric motor driven by electricity supplied from the battery, the electric propulsion device applying a propulsive force to the watercraft body; a jet propulsion device including an engine and a jet water flow generator driven by the engine to generate a jet water flow, the jet propulsion device applying a propulsive force to the watercraft body by the jet water flow; a generator that is driven by the engine to generate power and charge the battery; an electric starter that is supplied with power by the battery to start the engine; and a control device that controls the electric propulsion device and the jet propulsion device, in which the control device starts the engine when a condition that the driving of the electric propulsion device is started in a state where a remaining charge amount of the battery is less than a predetermined lower limit determination amount and the engine is being stopped is satisfied.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a partially broken side view of a jet propulsion watercraft according to a first embodiment of the present disclosure;

[0010] FIG. 2 is a plan view of the jet propulsion watercraft;

[0011] FIG. 3 is a schematic perspective view illustrating a sub manipulation device provided in the jet propulsion watercraft;

[0012] FIG. 4 is a view illustrating an example of an image displayed on a display provided in the jet propulsion watercraft;

[0013] FIG. 5 is a schematic plan view illustrating a periphery of a jet nozzle of the jet propulsion watercraft;

[0014] FIG. 6 is a schematic side view illustrating the periphery of the jet nozzle of the jet propulsion watercraft;

[0015] FIG. 7 is a plan cross-sectional view schematically illustrating a structure of an electric propulsion device of the jet propulsion watercraft;

[0016] FIG. 8 is a plan view schematically illustrating a propulsive force and the like acting on a watercraft body in a slide pattern;

[0017] FIG. 9 is a functional block diagram illustrating a control system of the jet propulsion watercraft;

[0018] FIG. 10 is a flowchart illustrating a mode decision method by a control device;

[0019] FIG. 11 is a flowchart for explaining battery monitoring control according to the first embodiment;

[0020] FIG. 12 is a flowchart illustrating contents of impeller monitoring control;

[0021] FIG. 13 is a flowchart illustrating contents of battery monitoring control according to a second embodiment;

[0022] FIG. 14 is a view illustrating an example of an image displayed on a display according to the second embodiment;

[0023] FIG. 15 is a flowchart illustrating contents of battery monitoring control according to a third embodiment;

[0024] FIG. 16 is a flowchart illustrating contents of battery monitoring control according to a fourth embodiment; and

[0025] FIG. 17 is a flowchart illustrating contents of battery monitoring control according to a fifth embodiment.DETAILED DESCRIPTION

[0026] Hereinafter, a first embodiment of a jet propulsion watercraft according to the present disclosure will be described with reference to the drawings. In the following description, a front-rear direction of a watercraft body of the jet propulsion watercraft, in detail, a direction connecting a bow and a stern is simply referred to as the front-rear direction, and the bow side is referred to as the front and the stern side is referred to as the rear. Furthermore, a left-right direction of the watercraft body of the jet propulsion watercraft, in detail, a direction orthogonal to the front-rear direction and to a vertical direction is simply referred to as the left-right direction. The front-rear direction and the left-right direction coincide with the front-rear direction and the left-right direction viewed from the driver riding on the jet propulsion watercraft. Direction indications, front, rear, left, and right in the drawings indicate the directions defined as described above.Configuration of Jet Propulsion Watercraft

[0027] FIG. 1 is a partially broken side view of a jet propulsion watercraft 1 according to a first embodiment of the present disclosure, and FIG. 2 is a plan view of the jet propulsion watercraft 1. The jet propulsion watercraft 1 is a watercraft that jets a water flow and moves on the water in reaction to the water flow. In the first embodiment, the jet propulsion watercraft 1 is a riding-type personal watercraft, also called a PWC. For this reason, hereinafter, the jet propulsion watercraft 1 is abbreviated as a PWC1. A line O1 in FIG. 2 is a line passing through the center of the watercraft body 10 of the PWC1 in the left-right direction.

[0028] The PWC1 includes, as a propulsion device that applies a propulsive force to the watercraft body 10, a jet propulsion device 2, and an electric propulsion device 3 that applies a propulsive force different from the jet propulsion device 2 to the watercraft body 10. The jet propulsion device 2 is an engine-type propulsion device and includes an engine 5 as a driving source. The electric propulsion device 3 is an electric-type propulsion device and includes a thruster motor 59 including an electric motor as a drive source. Here, the jet propulsion device 2 generates a propulsive force by driving of the engine 5. Hereinafter, driving / stopping of the jet propulsion device 2 will be simply referred to as driving / stopping of the engine 5 as appropriate. Driving of the thruster motor 59 causes the electric propulsion device 3 to generate a propulsive force. Hereinafter, the driving / stopping of the electric propulsion device 3 is simply referred to as driving / stopping of the thruster motor 59.

[0029] The watercraft body 10 includes a hull 11 and a deck 12 covering an upper side of the hull 11.

[0030] The hull 11 houses the engine 5, the thruster motor 59, and a starter 84. The starter 84 is an electric motor for starting the engine 5. The hull 11 houses a battery 80 that supplies power to various electric apparatuses provided in the watercraft body 10 such as the thruster motor 59 and the starter 84. The hull 11 houses a generator 82 that charges the battery 80.

[0031] A seat 14 is disposed on the deck 12. The seat 14 is a seat on which a driver M who drives the PWC1 is seated. The seat 14 may be a seat for plural persons on which not only the driver M but also fellow passengers can sit, or may be a seat for one person on which only the driver M can sit.

[0032] A steering handle 13 and a shift lever 23 that can be manipulated by the driver M or the like are provided in a front upper part of the deck 12. The steering handle 13 is a manipulator for changing an orientation of a jet nozzle 34 to be described later. The steering handle 13 is provided with an accelerator lever 21 and a start / stop switch 22. The accelerator lever 21 is a manipulator for changing an output of the engine 5. The start / stop switch 22 is a manipulator for switching between start and stop of the engine 5. The shift lever 23 is a manipulator for changing a position of a reverse bucket 7 to be described later.

[0033] A sub manipulation device 25 that can be manipulated by the driver M or the like is provided in the vicinity of the steering handle 13. FIG. 3 is a perspective view illustrating details of the sub manipulation device 25. The sub manipulation device 25 includes a pedestal 26, and a joystick 27, a first joy mode switch SW1, a first direction holding switch SW2, and a first fixed point holding switch SW3 that are supported by the pedestal 26. The joystick 27 is a manipulator for changing a movement direction of the watercraft body 10 when a navigation mode of the watercraft body 10 is a joy mode to be described later. The joystick 27 has a substantially cylindrical shape extending upward from the pedestal 26. As indicated by broken arrows in FIG. 3, the joystick 27 is tiltable in eight directions of front, back, left, right, diagonally front right, diagonally back right, diagonally front left, and diagonally back left from a neutral position. As indicated by chain arrows in FIG. 3, the joystick 27 is turnable rightward and leftward about its central axis in a state of being at the neutral position. The first joy mode switch SW1 is a switch for switching ON / OFF of the joy mode. The first direction holding switch SW2 is a switch for switching ON / OFF of a direction holding mode to be described later which is one of the navigation modes. The first fixed point holding switch SW3 is a switch for switching ON / OFF of a fixed point holding mode to be described later which is one of the navigation modes. The joystick 27 corresponds to a “first manipulator” of the present disclosure.

[0034] A display 15 is provided in front of the steering handle 13. The display 15 is a device that displays various types of information and notifies the driver M or the like of the information. FIG. 4 is a view illustrating an example of an image displayed on the display 15. For example, the display 15 displays a speed D1, a remaining amount of fuel D2, and a bow direction D3 of the watercraft body 10, and a current position D4 of the PWC1, and the like. The display 15 is a touch panel display. Namely, the driver M or the like can perform various input manipulations on the display 15. The display 15 corresponds to a “touch panel” and a “notification unit” of the present disclosure.

[0035] The display 15 displays a second joy mode switch SW11 having the same function as the first joy mode switch SW1 of the sub manipulation device 25. The display 15 displays a second direction holding switch SW12 having the same function as the first direction holding switch SW2 of the sub manipulation device 25. The display 15 displays a second fixed point holding switch SW13 having the same function as the first fixed point holding switch SW3 of the sub manipulation device 25. The display 15 displays a joy switch SW27 having the same function as the joystick 27. The joy switch SW27 corresponds to a “second manipulator” of the present disclosure.Jet Propulsion Device

[0036] The jet propulsion device 2 includes the engine 5, a jet pump 6, and the reverse bucket 7. The reverse bucket 7 corresponds to a “water flow changing device” in the present disclosure.

[0037] The engine 5 is an internal combustion engine, and generates combustion energy by combusting a mixed gas of fuel and air. The engine 5 is, for example, a water-cooled 4-stroke multi-cylinder engine driven using gasoline as fuel. The engine 5 includes a crankshaft 30 extending in the front-rear direction as an output shaft. The starter 84 is an electric motor for starting the engine 5. The starter 84 is coupled to the crankshaft 30 and forces it to rotate.

[0038] The jet pump 6 is disposed in an impeller passage 37. The impeller passage 37 is a passage having a water inlet 36 formed in a bottom surface 11A of the hull 11 as an inlet.

[0039] The jet pump 6 is a pump that generates a jet water flow. The jet pump 6 includes a pump shaft 31, a pump impeller 32, a venturi nozzle 33, and a jet nozzle 34. The pump shaft 31 is coaxially coupled to a rear end of the crankshaft 30. The pump impeller 32 is fixed to the pump shaft 31. When the engine 5 rotates, the pump impeller 32 rotates about its axis to generate a backward water flow. The venturi nozzle 33 and the jet nozzle 34 pressurize and accelerate the water sent from the pump impeller 32 to generate a jet water flow. The jet nozzle 34 has a jet port 35 that opens backward. The generated jet water flow is jetted backward from the jet port 35. This jet water flow applies a propulsive force to the watercraft body 10. The above jet pump 6 corresponds to a “jet water flow generator” of the present disclosure. Hereinafter, a propulsive force by a jet water flow is appropriately referred to as a jet propulsive force.

[0040] The jet nozzle 34 is disposed at a rear end part of the watercraft body 10 and behind a center of gravity G of the PWC1. As a result, the jet water flow is jetted from the rear end part of the watercraft body 10. The center of gravity G of the PWC1 is located, for example, in a region where the sheet 14 is disposed in plan view.

[0041] FIG. 5 is a schematic plan view illustrating a periphery of the jet nozzle 34. The jet nozzle 34 has a substantially cylindrical shape extending in the front-rear direction. The jet nozzle 34 is swingable in the left-right direction as indicated by a broken line, a solid line, and a chain line in FIG. 5. The jet nozzle 34 is of an electric type, and is swinged by a nozzle motor 39 (FIG. 2) including an electric motor. When the jet nozzle 34 swings, an orientation of the jet port 35 and a jet direction of a jet water flow are changed to the left and right.

[0042] Hereinafter, as for a position of the jet nozzle 34, a position where a central axis of the jet nozzle 34 extends straight in the front-rear direction and the jet port 35 opens straight backward as indicated by the solid line in FIG. 5 is referred to as a basic position. In addition, as for a swinging direction of the jet nozzle 34, a case where the jet nozzle 34 swings so that a rear end of the jet nozzle 34 moves to the left as indicated by the broken line from the solid line in FIG. 5 is referred to as swinging to the left, and a case where the jet nozzle swings to the opposite side is referred to as swinging to the right.

[0043] FIG. 6 is a schematic side view illustrating a periphery of the reverse bucket 7. The reverse bucket 7 is basically a device for switching between forward movement, backward movement, and stop of the watercraft body 10. The reverse bucket 7 is turnable in the up-down direction between a reverse position and a forward position. The reverse position is a position where the reverse bucket 7 covers the jet port 35 of the jet nozzle 34 from the back as indicated by a chain line in FIG. 6. The forward position is a position at which the jet port 35 is exposed as indicated by a broken line in FIG. 6. The position of the reverse bucket 7 is switched among the reverse position, the forward position, and a neutral position. The neutral position is an intermediate position between the forward position and the reverse position as indicated by a solid line in FIG. 6. The reverse bucket 7 is of an electric type, and is turned by a bucket motor 49 including an electric motor.

[0044] The reverse bucket 7 includes a main body wall 41 that covers the jet port 35 from the back in a state of being at the reverse position. The reverse bucket 7 includes a left wall part 42 and a right wall part 43 respectively extending forward from a left edge and a right edge of the main body wall 41 in a state of being at the reverse position. Through holes 44 and 45 are formed in the left wall part 42 and the right wall part 43, respectively.

[0045] When the reverse bucket 7 is at the forward position, the jet water flow jetted from the jet port 35 goes backward without being hindered by the reverse bucket 7. Accordingly, in a state where the reverse bucket 7 is at the forward position, a forward jet propulsive force is applied to the watercraft body 10.

[0046] In a state where the reverse bucket 7 is at the reverse position, the jet water flow jetted backward from the jet port 35 has an orientation changed forward by collision with the main body wall 41, and is jetted forward from the left and right through holes 44 and 45. As a result, in the state where the reverse bucket 7 is at the reverse position, a backward jet propulsive force is applied to the watercraft body 10.

[0047] In a state where the reverse bucket 7 is at the neutral position, the jet water flow jetted from the jet port 35 is divided into the left and right and advances to the left and right outer sides through the through holes 44 and 45. When amounts of water of the jet water flows passing through the left and right through holes 44 and 45 are equal to each other, the propulsive forces of the left and right jet water flows cancel each other, so that a jet propulsive force applied to the watercraft body 10 becomes substantially zero. Namely, the watercraft body 10 stops. On the other hand, when the amounts of water on the left and right sides are different, a propulsive force of one of the left and right jet water flows increases, so that a rightward or leftward jet propulsive force including substantially no front-rear direction component is applied to the watercraft body 10.

[0048] By combining the position of the jet nozzle 34 and the position of the reverse bucket 7, an orientation of a jet propulsive force applied to the watercraft body 10 can be changed in almost all directions. Specifically, when the position of the jet nozzle 34 is changed in a state where the reverse bucket 7 is at the forward position, the jet propulsive force changes its left and right orientations in a state of having a forward component. When the position of the jet nozzle 34 is changed in a state where the reverse bucket 7 is at the reverse position, the jet propulsive force changes its right and left orientations in a state of having a backward component. Furthermore, when the position of the jet nozzle 34 is changed in a state where the reverse bucket 7 is at the neutral position, the jet propulsive force changes its right and left orientations in a state of having no front-rear direction component. As described above, when the amounts of water of the jet water flow passing through the two through holes 44 and 45 are equal, the jet propulsive force becomes substantially zero.

[0049] As the orientation of the jet propulsive force is changeable in substantially all directions, the watercraft body 10 is movable in substantially all directions. However, the jet propulsive force is applied to the rear end part of the watercraft body 10. Therefore, when only the jet propulsive force is applied to the watercraft body 10, the watercraft body 10 moves with a change in an orientation of the bow except for a pattern of moving straight forward and straight backward.Generator

[0050] The generator 82 is driven by the engine 5 to generate power. The generator 82 is coupled to the crankshaft 30 with its rotor coaxial with the crankshaft 30. The generator 82 generates power by rotational driving of the rotor by the crankshaft 30. The generator 82 is connected to the battery 80, and electricity generated by the generator 82 is stored in the battery 80. In the first embodiment, the generator 82 rotates integrally with the engine 5 to generate power. Namely, the generator 82 is always rotationally driven to generate power during rotation of the engine.Electric Propulsion Device

[0051] FIG. 7 is a plan cross-sectional view schematically showing a structure of the electric propulsion device 3. The electric propulsion device 3 generates an auxiliary water flow directed outward in the left-right direction from a front part of the watercraft body 10. This auxiliary water flow applies a propulsive force to the watercraft body 10. The electric propulsion device 3 is a so-called electric thruster. In addition to the thruster motor 59, the electric propulsion device 3 includes a propeller shaft 51 extending left and right, an impeller 52 fixed to the propeller shaft 51, and a gear mechanism 53. The electric propulsion device 3 is disposed ahead of the center of gravity G of the PWC1. Hereinafter, the propulsive force by the auxiliary water flow is appropriately referred to as an auxiliary propulsive force.

[0052] The watercraft body 10 includes a water passage 55 at a position corresponding to the electric propulsion device 3. The water passage 55 is a passage penetrating a front part of the hull 11 in the left-right direction. The thruster motor 59 is disposed inside the hull 11. The propeller shaft 51, the impeller 52, and the gear mechanism 53 are housed inside the water passage 55. The propeller shaft 51 and the impeller 52 are driven by the thruster motor 59 to rotate about an axis extending in the left-right direction. Specifically, rotation input from the thruster motor 59 to the gear mechanism 53 is redirected by 90 degrees and then transmitted to the impeller 52. Rotation of the impeller 52 causes the water introduced into the water passage 55 to be jetted from one end (a left-side opening 55A or a right-side opening 55B) of the water passage 55. As a result, an auxiliary water flow, which is a water flow along the left-right direction, is generated.

[0053] The thruster motor 59 can rotate forward and backward. Orientation of the auxiliary water flow is switched by switching a rotation direction of the thruster motor 59. For example, when the thruster motor 59 rotates forward, a leftward auxiliary water flow is generated as indicated by an arrow Y51. The leftward auxiliary water flow applies a rightward auxiliary propulsive force to the watercraft body 10 as indicated by an arrow Y52. When the thruster motor 59 reversely rotates, a rightward auxiliary water flow is generated as indicated by an arrow Y53 in FIG. 7. The rightward auxiliary water flow applies a leftward auxiliary propulsive force to the watercraft body 10 as indicated by an arrow Y54.

[0054] The auxiliary water flow is generated at a front part of the PWC1. As a result, when the rightward auxiliary propulsive force (Y52) is applied to the front part of the watercraft body 10, a rightward, i.e., a clockwise yaw moment (Y55) is applied to the watercraft body 10. Therefore, when the jet propulsive force is not applied to the watercraft body 10 at this time, the watercraft body 10 turns clockwise without substantially moving in the front-rear direction as indicated by a solid line to a broken line in FIG. 7. In addition, when the leftward auxiliary propulsive force (Y54) is applied to the front part of the watercraft body 10, a counterclockwise yaw moment (Y56) is applied to the watercraft body 10. Therefore, when the jet propulsive force is not applied to the watercraft body 10 at this time, the watercraft body 10 turns counterclockwise without substantially moving in the front-rear direction as indicated by the solid line to a chain line in FIG. 7.Slide Movement

[0055] With the jet propulsion device 2 and the electric propulsion device 3 configured as described above, the watercraft body 10 is also movable in directions different from forward and backward while maintaining the orientation of the bow. Specifically, the reason why the orientation of the bow changes when the watercraft body 10 moves upon receiving a jet propulsive force is that a yaw moment caused by the jet propulsive force is applied to the rear end part of the watercraft body 10. Therefore, setting orientations and magnitudes of the jet propulsive force and the auxiliary propulsive force in the left-right direction to be the same enables the yaw moment caused by the jet propulsive force to be canceled by a yaw moment caused by the auxiliary propulsive force, thereby maintaining the orientation of the bow. Here, as described above, the watercraft body 10 is movable substantially in all directions upon receiving the jet propulsive force. Therefore, by setting orientations and magnitudes of the two propulsive forces in a manner as described above for each direction, the watercraft body 10 can be moved in almost all directions while maintaining the orientation of the bow. Straight forward movement of the watercraft body 10 while maintaining the orientation of the bow is realized by stopping the thruster motor 59, setting the reverse bucket 7 to the forward position, and setting the jet nozzle 34 to the basic position. Straight backward movement of the watercraft body 10 while maintaining the orientation of the bow is realized by stopping the thruster motor 59, setting the reverse bucket 7 to the reverse position, and setting the jet nozzle 34 to the basic position. Hereinafter, movement while the orientation of the bow of the watercraft body 10 is maintained is appropriately referred to as slide movement.

[0056] FIG. 8 is a view schematically illustrating a force applied to the watercraft body 10 during slide movement. FIG. 8 illustrates a state of the watercraft body 10 when the watercraft body 10 slides diagonally front right as an example of the slide movement.

[0057] In the example of FIG. 8, a jet water flow Y11 is jetted diagonally back left. As a result, a diagonally front right jet propulsive force F11 is applied to the watercraft body 10. In addition, a counterclockwise yaw moment YM11 is applied to the watercraft body 10 by a rightward component F11A of the jet propulsive force F11. In addition, in the example of FIG. 8, a leftward auxiliary water flow Y12 is also generated. As a result, a rightward auxiliary propulsive force F12 is applied to the watercraft body 10. A clockwise yaw moment YM12 is also applied to the watercraft body 10. In the example of FIG. 8, a magnitude of each of the propulsive forces F11 and F12, i.e., a strength of each of the water flows Y11 and Y12 is set such that the two yaw moments YM11 and YM12 cancel each other out. As a result, the watercraft body 10 receives a resultant force F13 of the two propulsive forces F11 and F12 in a state where the yawing is suppressed, and moves in a direction of the resultant force F13, i.e., diagonally front right as indicated by an arrow Y19. As described above, at the time of sliding the watercraft body 10, it is necessary to set the strength of each water flow so that the two yaw moments cancel each other.Control System

[0058] A control system of the PWC1 will be described. A control device 100 that outputs control signals to various devices mounted on the watercraft body 10 to control these devices is mounted on the watercraft body 10. FIG. 9 is a functional block diagram illustrating the control system of the PWC1. The control device 100 is a device including, as a main part, a microcomputer including a processor (CPU) that performs calculation and memories such as a ROM and a RAM.

[0059] The control device 100 receives signals from the steering handle 13, the accelerator lever 21, the start / stop switch 22, and the shift lever 23. The control device 100 receives signals, respectively from the joystick 27, the first joy mode switch SW1, the first direction holding switch SW2, and the first fixed point holding switch SW3 provided in the sub manipulation device 25. The control device 100 receives signals from the joy switch SW27, the second joy mode switch SW11, the second direction holding switch SW12, and the second fixed point holding switch SW13 on the display 15. In detail, these manipulators have built in sensors for detecting manipulation states thereof, and the control device 100 receives signals from these sensors.

[0060] An inertial measurement unit (IMU) 92, a speed sensor 94, and a battery sensor 96 are mounted on the watercraft body 10. The control device 100 receives signals from the IMU92, the speed sensor 94, and the battery sensor 96. The IMU92 is an inertial measurement device in which a three-axis gyro sensor and a three-axis acceleration sensor are combined. The IMU92 detects angular velocities around three axes orthogonal to each other and accelerations in three axis directions in the watercraft body 10. The IMU92 can calculate a bow direction of the watercraft body 10 on the basis of the angular velocity or the like, and also functions as a device for detecting the bow direction of the watercraft body 10. The speed sensor 94 detects a navigation speed of the watercraft body 10. The battery sensor 96 is a sensor for calculating a remaining charge amount of the battery 80. Specifically, the battery sensor 96 detects a battery current which is a current flowing in and out of the battery 80.

[0061] The control device 100 controls elements such as a fuel injection device and a spark plug provided for the engine 5 to control the output of the engine 5, and thus, a momentum of a jet water flow and a strength of a jet propulsive force. Here, as described above, the generator 82 rotates integrally with the engine 5. As a result, when the output of the engine 5 increases or decreases, a power generation amount of the generator 82 also increases or decreases substantially in proportion to the increase or decrease. The control device 100 controls the position of the jet nozzle 34 and the reverse bucket 7 to control the orientation of the jet propulsive force. The control device 100 controls an output and a rotation direction of the thruster motor 59 to control a momentum and an orientation of the auxiliary water flow, and thus control a strength and an orientation of the auxiliary propulsive force.

[0062] The control device 100 controls the starter 84 to switch between driving and stopping of the starter 84. The control device 100 controls display contents of the display 15. In the example of the image illustrated in FIG. 4, the bow direction D3 of the watercraft body 10 displayed on the display 15 is a direction specified by the IMU92. The velocity D1 of the watercraft body 10 displayed on the display 15 is a value detected by the velocity sensor 94. For example, the control device 100 outputs a control signal to the display 15 so that these pieces of information are displayed.

[0063] The control device 100 functionally includes a position specifying unit 101, a determination unit 102, a navigation control unit 103, a battery monitoring unit 104, and an impeller monitoring unit 105.

[0064] The position specifying unit 101 is a module that controls the position of the PWC1. The position specifying unit 101 has a GPS function and specifies a current position of the PWC1 on the basis of a signal from an artificial satellite. In the first embodiment, a GPS receiver is provided in the vicinity of the bow, and a position in the vicinity of the bow of the watercraft body 10 is specified. The current position D4 of the PWC1 displayed on the display 15 is the position specified by the position specifying unit 101.

[0065] The determination unit 102 is a module that performs various determinations regarding control of the PWC1. The navigation control unit 103 is a module that performs various calculations on the basis of a determination result of the determination unit 102 and the like and controls the jet propulsion device 2 and the like.Navigation Control

[0066] Control related to navigation of the watercraft body 10 performed by the control device 100 will be described. In the PWC1, the fixed point holding mode, the direction holding mode, the joy mode, and a jet navigation mode are set as navigation modes of the watercraft body 10. The fixed point holding mode is a mode for keeping the watercraft body 10 within a predetermined range. The direction holding mode is a mode for keeping the direction of the watercraft body 10 constant. The joy mode is a mode of moving the watercraft body 10 on the basis of manipulation on the joystick 27 or the joy switch SW27. The jet navigation mode is a mode of causing the watercraft body 10 to navigate only by the jet propulsive force on the basis of manipulation on the steering handle 13 or the like.

[0067] The determination unit 102 decides in which mode the watercraft body 10 is to be navigated. FIG. 10 is a flowchart illustrating a mode decision method by the determination unit 102.

[0068] As illustrated in FIG. 10, the determination unit 102 first determines whether the first fixed point holding switch SW3 or the second fixed point holding switch SW13 has been turned ON or not (step S1). In a case where the determination is YES and the fixed point holding switch SW3 or SW13 is turned ON, the determination unit 102 decides the navigation mode of the watercraft body 10 as the fixed point holding mode (step S2). When the navigation mode of the watercraft body 10 is decided to be the fixed point holding mode, the navigation control unit 103 executes fixed point holding control.

[0069] In a case where the determination in step S1 is NO, i.e., when the fixed point holding switches SW3 and SW13 are not turned ON, the determination unit 102 determines whether the first direction holding switch SW2 or the second direction holding switch SW12 is turned ON or not (step S3). When the determination is YES and the direction holding switch SW2 or SW12 is turned ON, the determination unit 102 decides the navigation mode of the watercraft body 10 as the direction holding mode (step S4). When the navigation mode of the watercraft body 10 is decided to be the direction holding mode, the navigation control unit 103 executes direction holding control.

[0070] In a case where the determination in step S3 is NO, i.e., when the direction holding switches SW2 and SW12 are not turned ON, the determination unit 102 determines whether the first joy mode switch SW1 or the second joy mode switch SW11 is turned ON or not (step S5). In case where the determination is YES and the joy mode switch SW1 or SW11 is turned ON, the determination unit 102 decides the navigation mode of the watercraft body 10 as the joy mode (step S6). When the navigation mode of the watercraft body 10 is decided to be the joy mode, the navigation control unit 103 executes joy mode control.

[0071] In a case where the determination in step S5 is NO, i.e., when the joy mode switches SW1 and SW11 are not turned ON, the determination unit 102 decides the navigation mode of the watercraft body 10 as the jet navigation mode (step S7). When the navigation mode of the watercraft body 10 is decided to be the jet navigation mode, the navigation control unit 103 executes jet navigation control.

[0072] Next, control contents of each mode will be described.Fixed Point Holding Control

[0073] At the start of the fixed point holding control, i.e., when the fixed point holding switch SW3 or SW13 is switched from OFF to ON, the navigation control unit 103 stops the engine 5 and the thruster motor 59. In a case where they are already stopped, the stopped state is maintained. The determination unit 102 sets a position of the PWC1 specified by the position specifying unit 101 at the time of the switching to an anchor point and stores the anchor point. In addition, the determination unit 102 sets an area in which a separation distance from the anchor point is equal to or less than a predetermined reference value to an anchor area and stores the anchor area.

[0074] Until the fixed point holding switch SW3 or SW13 that has been turned ON is turned OFF, the determination unit 102 continuously determines whether or not the current position of the PWC1 has moved to the outside of the anchor area. When it is determined that the current position of the PWC1 has moved to the outside of the anchor area, the navigation control unit 103 drives the engine 5 while maintaining the stop of the thruster motor 59. In addition, the navigation control unit 103 controls the reverse bucket 7 and the jet nozzle 34 so that the watercraft body 10 moves toward the anchor point. Then, when the position of the PWC1 nears the anchor point, the navigation control unit 103 stops the engine 5 again. The engine 5 is not necessarily stopped when the fixed point holding switch SW3 or SW13 is switched from OFF to ON and when the position of the PWC1 returns to the vicinity of the anchor point. However, in a case of driving the engine 5, the reverse bucket 7 is set to the neutral position and the jet nozzle 34 is set to the basic position.Direction Holding Control

[0075] At the start of the direction holding control, i.e., when the direction holding switch SW2 or SW12 is switched from OFF to ON, the determination unit 102 sets a bow direction detected by the IMU92 at the time of this switching to a reference direction and stores the reference direction.

[0076] Until the direction holding switch SW2 or SW12 that has been turned ON is turned OFF, the determination unit 102 continuously determines whether or not a current bow direction of the PWC1 has deviated from the reference direction. When it is determined that the current bow direction of the PWC1 has deviated from the reference direction, the navigation control unit 103 drives the engine 5 and the thruster motor 59. In a case where they are already driven, the driven state is maintained. In addition, the navigation control unit 103 controls the reverse bucket 7, the jet nozzle 34, and the thruster motor 59 so that the watercraft body 10 turns in a direction opposite to the deviated direction of the bow direction.Joy Mode Control

[0077] During the execution of the joy mode control, the navigation control unit 103 controls the jet propulsion device 2 and the electric propulsion device 3 on the basis of manipulation on the joystick 27 or the joy switch SW27. As illustrated in FIG. 4, the joy switch SW27 includes arrows respectively indicating eight tilting directions of the joystick 27 and arrows respectively indicating two turning directions of the same. In the first embodiment, the control device 100 recognizes that manipulation of touching each arrow included in the joy switch SW27, i.e., manipulation of touching each arrow with a finger of the driver M or the like is the same as tilting or turning manipulation of the joystick 27 in a direction corresponding to the touched arrow. In the following description of the joy mode control, a case where the joystick 27 is used as a manipulator will be described as a representative.

[0078] When the joystick 27 is manipulated to tilt forward from the neutral position, the navigation control unit 103 controls the propulsion devices 2 and 3 such that the watercraft body 10 slides forward. When the joystick 27 is manipulated to tilt backward from the neutral position, the navigation control unit 103 controls the propulsion devices 2 and 3 such that the watercraft body 10 slides backward. As described above, the forward and backward slide movement of the watercraft body 10 is realized by stopping the thruster motor 59 and driving the engine 5 to jet a jet water flow forward or backward.

[0079] When the joystick 27 is manipulated to tilt leftward from the neutral position, the navigation control unit 103 controls the propulsion devices 2 and 3 such that the watercraft body 10 slides leftward. When the joystick 27 is manipulated to tilt rightward from the neutral position, the navigation control unit 103 controls the propulsion devices 2 and 3 such that the watercraft body 10 slides rightward. When the joystick 27 is manipulated to tilt diagonally front right from the neutral position, the navigation control unit 103 controls the propulsion devices 2 and 3 such that the watercraft body 10 slides diagonally front right by 45 degrees. When the joystick 27 is manipulated to tilt diagonally front left from the neutral position, the navigation control unit 103 controls the propulsion devices 2 and 3 such that the watercraft body 10 slides diagonally front left by 45 degrees. When the joystick 27 is manipulated to tilt diagonally back right from the neutral position, the navigation control unit 103 controls the propulsion devices 2 and 3 such that the watercraft body 10 slides diagonally back right by 45 degrees. When the joystick 27 is manipulated to tilt diagonally back left from the neutral position, the navigation control unit 103 controls the propulsion devices 2 and 3 such that the watercraft body 10 slides diagonally back left by 45 degrees.

[0080] As described above, the slide movement of the watercraft body 10 in the oblique direction is realized by driving the thruster motor 59 and the engine 5. Furthermore, the slide movement of the watercraft body 10 in the oblique direction is realized by controlling the thruster motor 59, the engine 5, the reverse bucket 7, and the jet nozzle 34 such that the yaw moment caused by the propulsive force of the jet water flow and the yaw moment caused by the propulsive force of the auxiliary water flow cancel each other and a resultant force of these propulsive forces is in the oblique direction.

[0081] When the joystick 27 at the neutral position is manipulated to turn rightward about its central axis, the navigation control unit 103 controls the propulsion devices 2 and 3 so that the watercraft body 10 turns rightward, i.e., clockwise. When the joystick 27 at the neutral position is manipulated to turn leftward about its central axis, the navigation control unit 103 controls the propulsion devices 2 and 3 so that the watercraft body 10 turns leftward, i.e., counterclockwise. In the first embodiment, when the joystick 27 is manipulated to turn, the engine 5 is stopped while the thruster motor 59 is driven, so that the turning of the watercraft body 10 is realized only by the auxiliary propulsive force.

[0082] The slide movement or turning of the watercraft body 10 and the control for realizing the slide movement or turning are performed only while the joystick 27 or the joy switch SW27 is manipulated.Jet Navigation Control

[0083] In a case where the engine 5 is stopped when the jet navigation control is started, the navigation control unit 103 drives (starts) the engine 5. On the other hand, when the thruster motor 59 is being driven, the navigation control unit 103 stops the thruster motor 59.

[0084] In the jet navigation control, the navigation control unit 103 controls the jet propulsion device 2 on the basis of the manipulation on the steering handle 13, the accelerator lever 21, and the shift lever 23. Specifically, the navigation control unit 103 switches the position of the reverse bucket 7 on the basis of the manipulation on the shift lever 23. The navigation control unit 103 changes the position of the jet nozzle 34 on the basis of the manipulation on the steering handle 13. The navigation control unit 103 controls a throttle valve, a fuel injection device, and the like provided in the engine 5 on the basis of manipulation on the accelerator lever 21 to increase or decrease the output of the engine 5.Battery Monitoring Control

[0085] The battery monitoring unit 104 is a module that controls the propulsion devices 2 and 3 on the basis of a battery SOC or the like. The control of the propulsion devices 2 and 3 by the battery monitoring unit 104 is prioritized over the control of the propulsion devices 2 and 3 set for each navigation mode described above. Battery monitoring control performed by the battery monitoring unit 104 will be described with reference to FIG. 11. FIG. 11 is a flowchart for explaining the battery monitoring control. Each step illustrated in FIG. 11 is performed every predetermined time.

[0086] First, the battery monitoring unit 104 determines whether the battery SOC is less than a predetermined first SOC or not (step S11). The battery monitoring unit 104 calculates a battery SOC, which is a state of charge (SOC) of the battery 80, as a remaining charge amount of the battery 80 on the basis of a current value of the battery sensor 96. For example, the battery monitoring unit 104 calculates the battery SOC by integrating a battery current detected by the battery sensor 96. The first SOC is set in advance on the basis of an experiment or the like and stored in the control device 100. The first SOC is set to a value higher than the battery SOC at which the starter 84 cannot start the engine 5. In the first embodiment, the first SOC is set to a value slightly higher than an upper limit value of the battery SOC at which the starter 84 cannot start the engine 5. The first SOC corresponds to a“lower limit determination amount” of the present disclosure.

[0087] In a case where the determination in step S11 is YES and the battery SOC is less than the first SOC, the battery monitoring unit 104 prohibits driving of the thruster motor 59 (step S12). When the thruster motor 59 is driven, the battery monitoring unit 104 stops the thruster motor 59. Here, there is a case where the thruster motor 59 is driven in the direction holding mode and the joy mode among the four navigation modes. As a result, the battery monitoring unit 104 prohibits navigation of the watercraft body 10 in the direction holding mode and the joy mode (step S13). When the watercraft body 10 is navigating in the direction holding mode or the joy mode, the navigation of the watercraft body 10 in these modes is stopped.

[0088] After step S13, the battery monitoring unit 104 determines whether the engine 5 is stopped or not (step S14). The battery monitoring unit 104 makes this determination on the basis of a signal from a sensor or the like that detects a rotation speed of the engine 5. When the determination in step S14 is YES and the engine 5 is being stopped, the battery monitoring unit 104 drives, i.e., starts the engine 5 (step S15). Furthermore, the battery monitoring unit 104 sets a bucket position to the neutral position (N) and sets a nozzle position to the basic position (step S16), and ends the processing. In a state where the bucket position is at the neutral position and the nozzle position is at the basic position, the jet water flow is equally divided into the left and right, so that the jet propulsive force applied to the watercraft body 10 becomes zero and the watercraft body 10 stops.

[0089] In the first embodiment, steps S12, S13, S15, S16, and S18 once executed are continued until the battery SOC becomes equal to or greater than a second SOC greater than the first SOC. When the battery SOC becomes equal to or greater than the second SOC, the control device 100 returns to the processing of step S1 (FIG. 10). Namely, once the battery SOC decreases to less than the first SOC, the driving of the thruster motor 59 and the execution of the direction holding mode and the joy mode are prohibited until the battery SOC becomes equal to or greater than the second SOC. Once the battery SOC decreases to less than the first SOC, the engine 5 is driven at least until the battery SOC becomes equal to or greater than the second SOC. The second SOC is set to a value greater than the first SOC in advance and stored in the control device 100. The second SOC corresponds to a “determination amount” of the present disclosure.

[0090] As described above, when the engine 5 rotates, the generator 82 is rotationally driven to generate power. Therefore, when the engine 5 is started in step S15, power generation by the generator 82 is started.

[0091] On the other hand, when the determination in step S14 is NO and the engine 5 is being driven, the battery monitoring unit 104 determines whether or not a rotation-increase permission condition that the bucket position is at the neutral position (N) and the nozzle position is at the basic position is satisfied (step S17).

[0092] When the determination in step S17 is YES and the rotation-increase permission condition is satisfied, the battery monitoring unit 104 increases the engine rotation speed to a predetermined rotation speed (step S18), and ends the processing (returns to step S11). Specifically, the battery monitoring unit 104 sets, as a target rotation speed, the rotation speed higher, by a preset difference, than an engine rotation speed at the timing when the determination in step S11 is switched from NO to YES, and controls the throttle valve, the fuel injection device, and the like of the engine 5 so that the engine rotation speed becomes the target rotation speed. When the engine rotation speed increases, a rotation amount of the generator 82 also increases, and the power generation amount of the generator 82 increases. On the other hand, when the determination in step S17 is NO and the rotation-increase permission condition is not satisfied, the battery monitoring unit 104 ends the processing as it is (returns to step S11).

[0093] When the determination in step S11 is NO and the battery SOC is equal to or greater than the first SOC, the battery monitoring unit 104 determines whether a condition that the battery SOC is less than the second SOC and the thruster motor 59 is being driven is satisfied or not (step S19).

[0094] When the determination in step S19 is YES and the condition is satisfied, the battery monitoring unit 104 determines whether the engine 5 is being stopped or not as in step S14 (step S20).

[0095] When the determination in step S20 is YES and the engine 5 is being stopped, the battery monitoring unit 104 drives, i.e., starts the engine 5 (step S21). As a result, power generation by the generator 82 is started. Furthermore, the battery monitoring unit 104 sets the bucket position to the neutral position (N) and sets the nozzle position to the basic position (step S22), and ends the processing (returns to step S11). A condition that the thruster motor 59 is being driven and the engine 5 is being stopped is satisfied when the watercraft body 10 is subjected to the turning control while the navigation mode is set to the joy mode, or when the navigation mode is set to the direction holding mode and the direction holding control is performed. Namely, when one of the two controls is performed and the battery SOC decreases to less than the second SOC while the thruster motor 59 is being driven, or when one of the two controls is started to start the driving of the thruster motor 59 while the battery SOC is less than the second SOC, steps S21 and S22 are performed. In the first embodiment, at this time, the control is continued while steps S21 and S22 are performed. Specifically, the watercraft body 10 is turned by the thruster motor 59 while the engine 5 is driven in a state where the bucket position is at the neutral position and the nozzle position is at the basic position. Alternatively, the bow direction of the watercraft body 10 is changed by the thruster motor 59 while the engine 5 is driven in a state where the bucket position is at the neutral position and the nozzle position is at the basic position.

[0096] On the other hand, when the determination in step S19 is NO and the battery SOC is equal to or greater than the second SOC or the thruster motor 59 is stopped, and when the determination in step S19 is YES while the determination in step S20 is NO and the engine 5 is being driven, the battery monitoring unit 104 ends the processing as it is (returns to step S11). When the determination in step S20 is NO, the engine 5 and the generator 82 have already been driven, and the generator 82 continues to generate power.

[0097] As described in the foregoing, the battery monitoring unit 104 controls the thruster motor 59, the engine 5, the reverse bucket 7, and the jet nozzle 34 in preference to the control corresponding to the navigation mode, according to the battery SOC and a driving state of the thruster motor 59.Impeller Monitoring Control

[0098] The impeller monitoring unit 105 is a module that performs control related to abnormality determination of the impeller 52 of the electric propulsion device 3. Impeller monitoring control performed by the impeller monitoring unit 105 will be described with reference to FIG. 12. FIG. 12 is a flowchart for explaining the impeller monitoring control. Each step shown in FIG. 12 is performed every predetermined time. In the following description of the impeller monitoring control and FIG. 12, a case where the joystick 27, as a representative of the joystick 27 and the joy switch SW27, is used as a manipulator will be described.

[0099] First, the impeller monitoring unit 105 determines whether or not a condition that the joystick 27 is manipulated during navigation in the joy mode is satisfied (step S31). This determination is made on the basis of a determination result of the determination unit 102 and a signal from the joystick 27.

[0100] In a case where the determination in step S31 is NO, and the navigation is not being performed in the joy mode or the joystick 27 is not being manipulated, the impeller monitoring unit 105 ends the processing as it is (returns to step S31). On the other hand, in a case where the determination in step S31 is YES, and the joystick 27 is being manipulated during navigation in the joy mode, the impeller monitoring unit 105 determines whether or not the joystick 27 is manipulated to tilt forward or backward from the neutral position (step S32).

[0101] In a case where the determination in step S32 is YES and the joystick 27 is manipulated to tilt forward or backward from the neutral position, the impeller monitoring unit 105 ends the processing as it is (returns to step S31).

[0102] On the other hand, in a case where the determination in step S32 is NO and manipulation other than the above is performed on the joystick 27, the impeller monitoring unit 105 determines whether or not a manipulation amount of the joystick 27 is equal to or more than a predetermined manipulation amount for determination (step S33). The manipulation amount for use in the determination in step S33 is a duration of the manipulation on the joystick 27. Specifically, it is a time from the timing at which the manipulation currently being performed on the joystick 27 is started to the present. The manipulation amount for determination is preset and stored in the control device 100.

[0103] In a case where the determination in step S33 is NO and the manipulation amount of the joystick 27 is less than the manipulation amount for determination, the impeller monitoring unit 105 ends the processing as it is (returns to step S31).

[0104] On the other hand, in a case where the determination in step S33 is YES and the manipulation amount of the joystick 27 is equal to or more than the manipulation amount for determination, the impeller monitoring unit 105 then determines whether or not a watercraft body movement amount is less than a predetermined movement amount for determination (step S34). The watercraft body movement amount is a distance that the watercraft body 10 has moved from the timing when the manipulation currently performed on the joystick 27 has been started to the present. In the first embodiment, a movement distance of the bow is used as the watercraft body movement amount. The impeller monitoring unit 105 calculates the watercraft body movement amount on the basis of a position of the watercraft body 10 and the like specified by the position specifying unit 101. The movement amount for determination is preset and stored in the control device 100. The movement amount for determination is set to a value smaller than a minimum movement amount of the watercraft body 10 realized when the manipulation amount of the joystick 27 is set to the manipulation amount for determination during navigation in the joy mode while the electric propulsion device 3 is normal.

[0105] In a case where the determination in step S34 is NO and the watercraft body movement amount is equal to or more than the movement amount for determination, the impeller monitoring unit 105 ends the processing as it is.

[0106] On the other hand, when the determination in step S34 is YES and the watercraft body movement amount is less than the movement amount for determination, the impeller monitoring unit 105 determines that the impeller 52 is abnormal (step S35). Namely, when a movement amount of the watercraft body 10 is suppressed to be less than the movement amount for determination although the joystick 27 is manipulated until its manipulation amount becomes equal to or more than the manipulation amount for determination, it is considered that the impeller 52 is not normally rotated. Accordingly, when the determination in step S35 is YES, the impeller monitoring unit 105 determines that the impeller 52 is not normally rotating, i.e., is abnormal.

[0107] When determining that the impeller 52 is abnormal, the impeller monitoring unit 105 then determines whether the manipulation of the joystick 27 has ended or not (step S36). When the determination in step S36 is NO and the manipulation of the joystick 27 has not ended, the impeller monitoring unit 105 repeats step S36. Namely, the impeller monitoring unit 105 waits for the end of the manipulation of the joystick 27 and then performs the next step S37. When the manipulation of the joystick 27 ends, the thruster motor 59 is stopped.

[0108] In step S37, the impeller monitoring unit 105 stops the thruster motor 59 after reversely rotating the thruster motor for a predetermined time, and ends the processing (returns to step S31). Specifically, the impeller monitoring unit 105 causes the thruster motor 59 to rotate in a direction opposite to the rotation direction of the thruster motor 59 performed immediately before. As a result, the impeller 52 rotates in a direction opposite to the immediately preceding rotation direction. Namely, in step S37, the thruster motor 59 is driven such that the rotation direction of the impeller 52 is reversed. In addition, the impeller monitoring unit 105 stops the thruster motor 59 when a predetermined time has elapsed since the start of the reverse rotation of the thruster motor 59. The predetermined time is preset and stored in the control device 100.Operation and Effects

[0109] As described in the foregoing, in the PWC1 according to the first embodiment, as devices that apply a propulsive force to the watercraft body 10, the jet propulsion device 2 using the engine 5 that generates a jet water flow as a driving source and the electric propulsion device 3 using the thruster motor 59 that generates an auxiliary water flow as a driving source are mounted on the watercraft body 10. Therefore, by combining the propulsive forces generated by the propulsion devices 2 and 3, it is possible to apply propulsive forces of various directions and sizes to the watercraft body 10. Therefore, a degree of freedom of movement of the watercraft body is increased. For example, as described above, the slide movement of the watercraft body 10 is enabled by the combination of the two propulsive forces.

[0110] However, the thruster motor 59 is an electric motor supplied with power from the battery 80. Therefore, depending on a use situation of the thruster motor 59, the battery SOC may be excessively lowered, so that it may be difficult to various electric apparatuses may have a difficulty in appropriately operating. In the first embodiment, power is supplied to the starter 84 by the battery 80. Therefore, when the battery SOC becomes excessively small, there is a possibility that the engine 5 cannot be appropriately started by the starter 84.

[0111] To cope with this situation, in the PWC1 of the first embodiment, when the battery SOC becomes less than the first SOC, the driving of the thruster motor 59 is prohibited, and the power consumption by the thruster motor 59 is stopped. Therefore, it is possible to prevent the battery SOC from greatly decreasing from the first SOC, i.e., to prevent the battery SOC from excessively decreasing. Therefore, it is possible to ensure appropriate operation of various electric apparatuses and start of the engine 5.

[0112] In particular, in the PWC1 of the first embodiment, the first SOC is set to a value slightly higher than the upper limit value of the battery SOC at which the engine 5 cannot be started. Therefore, it is possible to prevent the starter 84 from being unable to start the engine 5 due to a shortage of the battery SOC.

[0113] Furthermore, in the PWC1 of the first embodiment, when the battery SOC becomes less than the first SOC, the engine 5 is controlled so that the power generation amount of the generator 82 increases. Specifically, when the battery SOC becomes less than the first SOC while the engine 5 is stopped, the engine 5 is started and power generation by the generator 82 is started. Namely, the power generation amount of the generator 82 is increased from zero. Therefore, the battery SOC can be increased again.

[0114] Here, when the engine 5 is automatically started as the battery SOC becomes less than the first SOC, if the jet water flow generated by the engine 5 is jetted from the front side or the rear side of the watercraft body 10, the watercraft body 10 moves forward or backward, and the driver M may feel uncomfortable.

[0115] To cope with this situation, in the PWC1 of the first embodiment, at the time of automatically starting the engine 5 as the battery SOC becomes less than the first SOC, the reverse bucket 7 is set to the neutral position, and the jet water flow is jetted separately to the left and right. Therefore, it is possible to suppress the watercraft body 10 from making forward or backward movement unexpected by the driver M. In particular, in the PWC1 of the first embodiment, the reverse bucket 7 is set to the neutral position, and the jet nozzle 34 is set to the basic position. Therefore, since the jet water flow is equally divided in the left-right direction, it is possible to prevent the watercraft body 10 from making movement unexpected by the driver M.

[0116] Furthermore, in the PWC1 of the first embodiment, when the battery SOC becomes less than the first SOC during driving of the engine 5, the rotation speed of the engine 5 is increased, and the power generation amount of the generator 82 is increased. Therefore, the battery SOC can be increased early.

[0117] The control for increasing the engine speed is performed when the position of the reverse bucket 7 is at the neutral position and the position of the jet nozzle 34 is at the basic position. Therefore, it is possible to prevent the watercraft body 10 from making movement unexpected by the driver M as the engine speed increases.

[0118] In addition, in the PWC1 of the first embodiment, the engine 5 is started when a condition that while the engine is stopped, the thruster motor 59 is driven and the battery SOC is decreased to less than the second SOC is satisfied, or when a condition that the driving of the thruster motor 59 is started while the engine is stopped and the battery SOC is less than the second SOC is satisfied. Therefore, it is possible to prevent the battery SOC from further decreasing from the second SOC as power is consumed by the thruster motor 59. In addition, when the engine 5 is started as the above conditions are satisfied, the reverse bucket 7 is placed at the neutral position, and the jet water flow is jetted separately to the left and right. Therefore, it is possible to suppress the watercraft body 10 from making forward or backward movement unexpected by the driver M. Moreover, the jet nozzle 34 is set to the basic position. Therefore, since the jet water flow is equally divided in the left-right direction, it is possible to more reliably prevent the watercraft body 10 from making movement unexpected by the driver M.

[0119] Furthermore, in the PWC1 of the first embodiment, when it is determined that the impeller 52 of the electric propulsion device 3 is abnormal, the rotation direction of the thruster motor 59 is made opposite to the immediately preceding direction, so that the rotation of the impeller 52 is reversed. Therefore, when an abnormality occurs in the impeller 52 due to entanglement of algae or the like, the algae or the like entangled in the impeller 52 can be removed.

[0120] Also in the PWC1 of the first embodiment, the impeller 52 is determined to be abnormal when the manipulation amount of the joystick 27 or the joy switch SW27 for manipulating the thruster motor 59 is equal to or more than the manipulation amount for determination and the movement amount of the watercraft body 10 is less than the movement amount for determination. Therefore, an abnormality of the impeller 52 can be determined without providing a sensor or the like that detects a rotation state of the impeller 52.

[0121] In addition, in the PWC1 of the first embodiment, two manipulators, the joystick 27 and the joy switch SW27, are provided as manipulators in the joy mode for driving the thruster motor 59 to navigate the watercraft body 10, i.e., manipulators for manipulating the thruster motor 59. Therefore, convenience is improved. In particular, the joy switch SW27 is a switch displayed on the touch panel display 15, and the thruster motor 59 can be easily manipulated by touch manipulation of the joy switch SW27.Second Embodiment

[0122] FIG. 13 is a flowchart corresponding to FIG. 11. FIG. 13 shows control performed by a control device 100 of a PWC1 according to a second embodiment.

[0123] Also in the PWC1 of the second embodiment, the above-described steps S11 to S18 are performed similarly to the first embodiment. On the other hand, in the PWC1 according to the second embodiment, when both of the condition that the battery SOC is equal to or greater than the first SOC and less than the second SOC and the thruster motor 59 is being driven (the condition that the determination in step S19 is YES) and the condition that the engine 5 is being stopped (the condition that the determination in step S20 is YES) are satisfied, the engine 5 is not automatically started, but a notification prompting the driver M to start the engine 5 is given (step S221). Specifically, the control device 100 displays, on the display 15, that the driver M should start the engine 5, to prompt the driver M to start the engine 5. In the example of FIG. 14, when the above condition is satisfied, the control device 100 displays a wording D10“WARNING! Start engine” on the display 15. For example, the control device 100 continues this display until the engine 5 is started.

[0124] Configurations other than the above configuration are similar to those of the first embodiment, and description of other configurations is omitted.

[0125] According to the PWC1 of the second embodiment, it is possible to prompt the driver M to start the engine 5 when the battery SOC is low. Therefore, the decrease in the battery SOC can be suppressed by the power generation of the generator 82 accompanying the driving of the engine 5. Furthermore, by starting the engine 5 by the driver M himself / herself, it is possible to prevent the driver M from feeling uncomfortable as the engine 5 starts. Note that effects based on the same configuration included in the second embodiment as that of the first embodiment can also be obtained in the second embodiment.

[0126] Here, in the second embodiment, steps S11 to S18 illustrated in FIG. 13 may be omitted. Namely, the controls of stopping the thruster motor 59, starting the engine 5, and increasing the rotation speed of the engine 5 as the battery SOC becomes less than the first SOC may be omitted. In a case where these are omitted, when the battery SOC is less than a predetermined value (second SOC), and the thruster motor 59 is being driven and the engine is stopped, only a notification for prompting the start of the engine is made, and automatic control of the thruster motor 59 and the engine 5 by the control device 100 is not performed.Third Embodiment

[0127] FIG. 15 is a flowchart corresponding to FIG. 11. FIG. 15 illustrates control performed by a control device 100 of a PWC1 according to a third embodiment. As illustrated in FIG. 15, in the PWC1 of the third embodiment, steps S19 to S22 in the first embodiment illustrated in FIG. 11 are not performed. In addition, in the PWC1 of the third embodiment, although steps S12 to S18 in the first embodiment are performed, implementation conditions thereof are different from those of the first embodiment.

[0128] Specifically, in the PWC1 of the third embodiment, when a condition that the battery SOC is less than a predetermined fourth SOC and the thruster motor 59 is being driven (a condition that the determination in step S401 is YES) is satisfied, step S12 and subsequent steps are performed. Namely, in the PWC1 of the third embodiment, when the battery SOC decreases to less than the fourth SOC in a state where the thruster motor 59 is being driven, or when the driving of the thruster motor 59 is started in a state where the battery SOC is less than the fourth SOC, the driving of the thruster motor 59 is prohibited (stopped) (step S12), and navigation in the direction holding mode and the joy mode is prohibited (stopped) (step S13). In a case where the engine is being stopped (when the determination in step S14 is YES), the engine 5 is started (step S15), the position of the reverse bucket 7 is set to neutral, and the position of the jet nozzle is set to the basic position (step S16). In a case where the engine is being driven when the above condition is satisfied, and the position of the reverse bucket 7 is neutral, and the position of the jet nozzle is at the basic position, the rotation speed of the engine 5 is increased to the predetermined rotation speed (step S18). Furthermore, in the PWC1 of the third embodiment, when a condition that the battery SOC is less than the predetermined fourth SOC and the thruster motor 59 is being driven is not satisfied, the processing is ended as it is. In the third embodiment, steps S12, S13, S15, S16, and S18 once performed are continued until the battery SOC reaches a predetermined value larger than the fourth SOC. The fourth SOC is set to a value higher than the battery SOC at which the starter 84 cannot start the engine 5. In the third embodiment, the fourth SOC is set to a value slightly higher than the upper limit value of the battery SOC at which the starter 84 cannot start the engine 5. The fourth SOC corresponds to the “determination amount” of the present disclosure.

[0129] Configurations other than the above configuration are similar to those of the first embodiment, and description of other configurations is omitted.

[0130] The PWC1 of the third embodiment also prevents the thruster motor 59 from consuming power in a state where the battery SOC is low. Therefore, it is possible to prevent the battery SOC from being excessively lowered. In addition, also in the PWC1 of the third embodiment, a power generation opportunity of the generator 82 accompanying the driving of the engine 5 and a power generation amount increase opportunity accompanying an increase in the rotation speed of the engine 5 increase. Accordingly, it is also possible to prevent the battery SOC from being excessively lowered. Note that effects based on the same configuration included in the third embodiment as that of the first embodiment can also be obtained in the third embodiment.Fourth Embodiment

[0131] FIG. 16 is a flowchart corresponding to FIG. 11. FIG. 16 illustrates control performed by a control device 100 of a PWC1 according to a fourth embodiment. As illustrated in FIG. 16, in the PWC1 of the fourth embodiment, steps S12 and S13 and steps S19 to S22 in the first embodiment illustrated in FIG. 11 are not performed.

[0132] Specifically, in the PWC1 according to the fourth embodiment, the driving of the thruster motor 59 is not prohibited (stopped) even when the battery SOC becomes less than the first SOC, and the control to start the engine 5 being stopped (step S15) or the control to raise the engine 5 to the predetermined rotation speed (step S18) is performed. Similarly to the first embodiment, for starting the engine 5 being stopped, the position of the reverse bucket 7 is set to neutral, and the position of the jet nozzle is set to the basic position (step S16). Furthermore, the control for raising the engine 5 to the predetermined rotation speed is performed under a condition that the position of the reverse bucket 7 is neutral and the position of the jet nozzle is the basic position. In the fourth embodiment, steps SS15, S16, and S18 once performed are continued until the battery SOC reaches a predetermined value larger than the first SOC. In addition, in the fourth embodiment, when the battery SOC is equal to or greater than the first SOC, the processing is ended as it is without starting the engine 5 or the like.

[0133] Configurations other than the above configuration are similar to those of the first embodiment, and description of other configurations is omitted.

[0134] Also with the PWC1 of the fourth embodiment, when the battery SOC is low, it is possible to prevent the battery SOC from being excessively lowered because a power generation opportunity of the generator 82 accompanying the driving of the engine 5 and a power generation amount increase opportunity accompanying an increase in the rotation speed of the engine 5 increase. Note that effects based on the same configuration included in the fourth embodiment as that of the first embodiment can also be obtained in the fourth embodiment.Fifth Embodiment

[0135] FIG. 17 is a flowchart corresponding to FIG. 16. FIG. 17 illustrates control performed by a control device 100 of a PWC1 according to a fifth embodiment. As illustrated in FIG. 17, in the PWC1 of the fifth embodiment, steps S14 to S18 are performed similarly to the fourth embodiment illustrated in FIG. 16. On the other hand, in the PWC1 of the fifth embodiment, the conditions under which steps S14 to S18 are performed are different from those of the fourth embodiment.

[0136] Specifically, in the PWC1 of the fifth embodiment, when a condition that the battery SOC is less than the first SOC and the thruster motor 59 is being driven (a condition that determination in step S601 is YES) is satisfied, step S14 and subsequent steps are performed. Namely, in the PWC1 of the fifth embodiment, when the battery SOC decreases to less than the first SOC in a state where the thruster motor 59 is being driven, or when the driving of the thruster motor 59 is started in a state where the battery SOC is less than the first SOC, starting the engine 5 (step S15) and increasing the rotation speed of the engine 5 are performed (step S18).

[0137] Configurations other than the above configuration are similar to those of the fourth embodiment, and description of other configurations is omitted.

[0138] The PWC1 of the fifth embodiment also prevents a decrease in the battery SOC due to power consumption by the thruster motor 59 when the thruster motor 59 is driven in a state where the battery SOC is low. Therefore, it is possible to prevent the battery SOC from being excessively lowered. Note that effects based on the same configuration included in the fifth embodiment as that of the fourth embodiment can also be obtained in the fifth embodiment.Other Modifications

[0139] In the first embodiment, steps S19 to S22 illustrated in FIG. 11 may be omitted.

[0140] In the first to third embodiments, the case where the driving of the thruster motor 59 is prohibited in step S12 illustrated in FIGS. 11, 13, and 15 has been described. Alternatively, the output of the thruster motor 59 may be reduced to suppress the driving of the thruster motor 59. In this configuration, step S13 may be omitted.

[0141] In the first to third embodiments, the control for starting the stopped engine 5 and the control for increasing the rotation speed of the engine 5 may be omitted. Namely, steps S14 to S18 illustrated in FIGS. 11, 13, and 15 may be omitted. Steps S14 to S16 may be omitted. Steps S14, S17, and S18 may be omitted.

[0142] The description has been made of a case in which in step S19 of the first and second embodiments, step S401 of the third embodiment, and step S601 of the sixth embodiment, it is determined whether or not the condition that the battery SOC is less than the predetermined value and the thruster motor 59 is being driven is satisfied, and when the condition is satisfied, stop of the thruster motor 59, start of the engine, and the like are performed. Alternatively, as the above condition, a condition that the driving of the thruster motor 59 is started in a state where the battery SOC is less than a predetermined value may be used.

[0143] In each of the above embodiments, the case has been described in which, when step S15 is performed, i.e., when the engine 5 that has been stopped is forcibly started, step S16 is performed to set the reverse bucket 7 to the neutral position and set the position of the jet nozzle 34 to the basic position. However, the control of changing these positions may be omitted. Namely, step S16 may be omitted. Furthermore, the control of setting the position of the jet nozzle 34 to the basic position may be omitted, and only the control of setting the reverse bucket 7 to the neutral position may be performed. Even when the jet nozzle 34 is displaced from the basic position, the forward or backward movement of the watercraft body 10 is suppressed as long as the jet water flow is distributed to the left and right by the reverse bucket 7. A specific device for changing the orientation of the jet water flow is not limited to the jet nozzle 34 and to the reverse bucket 7 described above.

[0144] In the second embodiment, the case has been described in which the predetermined wording is displayed on the display 15 to prompt the driver M to start the engine 5. However, the notification method for prompting the start of the engine 5 is not limited to the display of wording on the display 15. For example, a notification for prompting the start of the engine 5 may be made by a method of displaying a symbol or the like on the display 15 or a method of generating sound from a speaker provided on the watercraft body 10.

[0145] In each of the above embodiments, the description has been made with the case where it is determined whether the impeller 52 is abnormal or not on the basis of the manipulation amount of the joystick 27 or the joy switch SW27 and the movement amount of the watercraft body 10. However, the method for determining whether the impeller 52 is abnormal or not is not limited thereto.

[0146] Furthermore, the manipulator for manipulating the thruster motor 59 is not limited to the joystick 27 and the joy switch SW27. For example, instead of or in addition to the joy switch SW27, a manipulator provided in a communication unit capable of communicating with the control device 100 may be used as a manipulator for manipulating the thruster motor 59.

[0147] In each of the above embodiments, the description has been made of the case where power is supplied from the common battery 80 to various electric apparatuses including the thruster motor 59 and the starter 84. Alternatively, the watercraft body 10 may be provided with a battery that supplies power to the thruster motor 59 alone separately from the battery that supplies power to other electric apparatuses including the starter 84. Hereinafter, a battery that supplies power to the thruster motor 59 alone is referred to as a thruster battery, and a battery that supplies power to other electric apparatuses is referred to as a main battery. In a case where the thruster battery and the main battery are separately provided, a configuration realized by replacing the battery 80 in each of the above embodiments with the thruster battery may be adopted as the configuration of the PWC1.

[0148] For example, as in steps S11 and S12 illustrated in FIG. 11, the driving of the thruster motor 59 may be prohibited (stopped) when the SOC of the thruster battery becomes less than a predetermined value. In the case where the thruster battery and the main battery are separately provided, when the SOC of the thruster battery becomes less than the predetermined value, a crew member of the watercraft body 10 may be notified that the SOC of the thruster battery is low by the display 15 or the like.

[0149] When assuming that a capacity of the thruster battery in a fully charged state is a full charge capacity, an initial capacity of the thruster battery is an initial capacity, an amount of electricity consumed by the thruster motor 59 is a thruster consumption amount, and an amount of electricity charged from the generator 82 to the thruster battery is an ACG charge amount, the SOC of the thruster battery can be calculated by the formula “(initial capacity−thruster consumption amount+ACG charge amount) / full charge capacity”. Here, the initial capacity is a discharge capacity of the thruster battery before the thruster battery is charged by the generator 82 as when the thruster battery is first mounted on the watercraft body 10, and can be obtained by detecting a voltage of the thruster battery. The thruster consumption amount can also be obtained from the specifications of the thruster motor 59. Namely, a preset value can be used as the thruster consumption amount. In addition, the ACG charge amount can be obtained from the rotation speed of the generator 82 or the like.

[0150] The functionality of the elements disclosed herein may be implemented using one or more circuitry or processing circuitry which includes general purpose processors, special purpose processors, integrated circuits, ASICs (“Application Specific Integrated Circuits”), FPGAs (“Field Programmable Gate Arrays”) and / or conventional circuitry. The functionality of the elements disclosed herein may be implemented using one or more circuitry or processing circuitry which includes combinations of general purpose processors, special purpose processors, integrated circuits, ASICs, FPGAs, or conventional circuitry. The one or more circuitry or processing circuitry is programmed, using one or more programs stored together or individually in one or more memories, or otherwise configured to perform the disclosed functionality. Processors are considered processing circuitry or circuitry as they include transistors and other circuitry therein. The processor may be a programmed processor which executes a program stored in a memory. In the disclosure, the circuitry, units, or means are hardware that carry out or are programmed to perform the recited functionality, alone or in combination with one another. The hardware may be any hardware disclosed herein which is programmed or configured to carry out the recited functionality.

[0151] There is a memory that stores a computer program which includes computer instructions. The computer instructions provide the logic and routines that enable the hardware to perform the method disclosed herein. The hardware includes, e.g., processing circuitry or circuitry. The computer program can be implemented in known formats as a computer-readable storage medium, a computer program product, a memory device, a record medium such as a CD-ROM or DVD, and / or the memory of a FPGAs or ASICs.Conclusion

[0152] The above embodiments and modifications thereof include the following disclosure.

[0153] A jet propulsion watercraft according to an aspect of the present disclosure includes: a watercraft body; a battery; an electric propulsion device including an electric motor driven by electricity supplied from the battery, the electric propulsion device applying a propulsive force to the watercraft body; a jet propulsion device that generates a jet water flow by a power source different from the electric motor and applies a propulsive force to the watercraft body by the jet water flow; and a control device that controls the electric propulsion device and the jet propulsion device, in which the control device controls the electric propulsion device on the basis of a remaining charge amount of the battery.

[0154] According to the present disclosure, by combining the propulsive forces generated by the two propulsion devices, propulsive forces of various directions and sizes can be applied to the watercraft body. Therefore, a degree of freedom of movement of the watercraft body is increased. However, since the electric propulsion device includes the electric motor driven by electricity supplied from the battery, the remaining charge amount of the battery is likely to decrease. When the remaining charge amount of the battery is excessively lowered, it is difficult for an electric apparatus such as the electric propulsion device mounted on the watercraft body to appropriately operate. To cope with this situation, in the jet propulsion watercraft according to the present disclosure, since the electric propulsion device is controlled on the basis of the remaining charge amount of the battery, an amount of power consumed by the electric propulsion device can be adjusted according to the remaining charge amount of the battery, so that the remaining charge amount of the battery can be prevented from becoming excessively small.

[0155] Preferably, the control device suppresses driving of the electric propulsion device when a remaining charge amount of the battery is less than a predetermined lower limit determination amount.

[0156] According to this mode, it is possible to prevent the remaining charge amount of the battery from further greatly decreasing from the lower limit determination amount by the driving of the electric propulsion device.

[0157] Preferably, the power source of the jet propulsion device includes an engine that generates combustion energy, the jet propulsion watercraft including: a generator that is driven by the engine to generate power and charge the battery; and an electric starter that is powered by the battery to start the engine.

[0158] According to this mode, the engine can apply a propulsive force to the watercraft body, and the engine can drive the generator to charge the battery. Furthermore, in the jet propulsion watercraft according to the present disclosure, the remaining charge amount of the battery is prevented from becoming excessively small as described above. Therefore, the starter supplied with power from the battery is provided to enable starting of the engine while preventing the starter and thus the engine from not being appropriately driven due to a small remaining charge amount of the battery.

[0159] Preferably, the control device suppresses driving of the electric propulsion device when a remaining charge amount of the battery is less than a predetermined lower limit determination amount.

[0160] According to this mode, it is possible to prevent the remaining charge amount of the battery from further greatly decreasing from the lower limit determination amount by the driving of the electric propulsion device. Therefore, it is possible to prevent the starter and the engine from becoming undrivable as the remaining charge amount of the battery runs short.

[0161] Preferably, the control device controls the engine to increase a power generation amount of the generator when a remaining charge amount of the battery is less than a predetermined lower limit determination amount.

[0162] According to this mode, the battery can be charged when the remaining charge amount of the battery is less than the lower limit determination amount.

[0163] Preferably, the control device starts the engine when the engine is stopped and the remaining charge amount of the battery is less than the lower limit determination amount.

[0164] According to this mode, when the remaining charge amount of the battery is less than the lower limit determination amount, it is possible to start power generation by the generator and charge the battery.

[0165] Preferably, the jet propulsion device includes a water flow changing device capable of changing an orientation of the jet water flow, and the control device controls the water flow changing device so that the orientation of the jet water flow is in both left and right directions of the watercraft body when the engine is started as the remaining charge amount of the battery is less than the lower limit determination amount while the engine is stopped.

[0166] According to this mode, when the engine is automatically started as the remaining charge amount of the battery is less than the lower limit determination amount, it is possible to suppress the watercraft body from making forward or backward movement unexpected by the driver.

[0167] Preferably, the lower limit determination amount is set to a value higher than a capacity of the battery by which the engine cannot be started by the starter.

[0168] According to this mode, the engine can be more reliably started by the starter.

[0169] Preferably, the control device starts the engine when a condition that the driving of the electric propulsion device is started in a state where a remaining charge amount of the battery is less than a predetermined determination amount and the engine is being stopped is satisfied.

[0170] According to this mode, when the electric propulsion device starts to be driven and the remaining charge amount of the battery may further decrease from the determination amount, power generation by the generator can be started. Therefore, it is possible to prevent the remaining charge amount of the battery from greatly decreasing from the determination amount.

[0171] Preferably, the jet propulsion device includes a water flow changing device capable of changing an orientation of the jet water flow, and the control device controls the water flow changing device so that an orientation of the jet water flow is in both left and right directions of the watercraft body when the engine is started as the condition is satisfied.

[0172] According to this mode, when the engine is automatically started as the remaining charge amount of the battery is less than the determination amount, it is possible to suppress the watercraft body from making forward or backward movement not intended by the driver.

[0173] Preferably, a notification unit that notifies a crew member of the watercraft body is provided, and the control device causes the notification unit to notify the crew member of the watercraft body to start the engine when a condition that the driving of the electric propulsion device is started in a state where a remaining charge amount of the battery is less than a predetermined determination amount and the engine is being stopped is satisfied.

[0174] According to this mode, the engine can be started by a crew member such as a driver when the remaining battery charge amount is low. Therefore, further reduction of the remaining battery charge amount can be suppressed by the power generation of the generator accompanying the driving of the engine. In addition, since the driver starts the engine by himself / herself, it is possible to prevent the driver from feeling uncomfortable about the start of the engine as compared with a case where the engine is automatically started.

[0175] Preferably, the determination amount is set to a value higher than a capacity of the battery at which the engine cannot be started by the starter.

[0176] According to this mode, the engine can be more reliably started by the starter.

[0177] Preferably, the electric propulsion device includes an impeller that is rotationally driven by the electric motor to generate the propulsive force, and the control device controls the electric motor such that a rotation direction of the impeller is reversed when an abnormality occurs in the impeller.

[0178] According to this mode, when an abnormality occurs in the impeller due to entanglement of algae or the like, the algae or the like entangled in the impeller can be removed.

[0179] Preferably, a motor manipulator that manipulates the electric motor is provided, and the control device determines whether an abnormality has occurred in the impeller or not on the basis of a manipulation amount of the motor manipulator and a movement amount of the watercraft body.

[0180] According to this mode, an abnormality of the impeller can be determined without providing a sensor or the like that detects the rotation state of the impeller.

[0181] Preferably, there are provided a first manipulator that is provided on the watercraft body so as to be tiltable in a plurality of directions and that manipulates the electric propulsion device, and a second manipulator that is provided separately from the first manipulator and is capable of manipulating the electric propulsion device.

[0182] According to this mode, the driver can select a manipulator to be used from the first manipulator and the second manipulator. Therefore, convenience is improved.

[0183] Preferably, the second manipulator is a touch panel provided on the watercraft body.

[0184] According to this mode, the electric propulsion device can be manipulated by touch manipulation on the touch panel.

[0185] A jet propulsion watercraft according to another aspect of the present disclosure includes: a watercraft body; a battery; an electric propulsion device including an electric motor driven by electricity supplied from the battery, the electric propulsion device applying a propulsive force to the watercraft body; a jet propulsion device including an engine and a jet water flow generator driven by the engine to generate a jet water flow, the jet propulsion device applying a propulsive force to the watercraft body by the jet water flow; a generator that is driven by the engine to generate power and charge the battery; an electric starter that is supplied with power by the battery to start the engine; and a control device that controls the electric propulsion device and the jet propulsion device, in which the control device controls the engine to increase a power generation amount of the generator when a remaining charge amount of the battery is less than a predetermined lower limit determination amount.

[0186] According to the present disclosure, by combining the propulsive forces generated by the two propulsion devices, propulsive forces of various directions and sizes can be applied to the watercraft body. Therefore, a degree of freedom of movement of the watercraft body is increased. However, since the electric propulsion device includes the electric motor driven by electricity supplied from the battery, the remaining charge amount of the battery is likely to decrease. When the remaining charge amount of the battery is excessively lowered, it is difficult for an electric apparatus such as the electric propulsion device mounted on the watercraft body to appropriately operate. By contrast, in the jet propulsion watercraft according to the present disclosure, when the remaining charge amount of the battery becomes less than the lower limit determination amount, the power generation amount of the generator is increased. Therefore, it is possible to prevent the remaining charge amount of the battery from further greatly decreasing from the lower limit determination amount. Therefore, the starter and the engine can be appropriately operated.

[0187] Preferably, the control device starts the engine when the engine is being stopped and the remaining charge amount of the battery is less than the lower limit determination amount.

[0188] According to this mode, when the remaining charge amount of the battery is less than the lower limit determination amount, it is possible to start power generation by the generator and charge the battery.

[0189] Preferably, the jet propulsion device includes a water flow changing device capable of changing an orientation of the jet water flow, and the control device controls the water flow changing device so that the orientation of the jet water flow is in both left and right directions of the watercraft body when the engine is started as the remaining charge amount of the battery is less than the lower limit determination amount while the engine is stopped.

[0190] According to this mode, when the engine is automatically started as the remaining charge amount of the battery is less than the lower limit determination amount, it is possible to suppress the watercraft body from making forward or backward movement unexpected by the driver.

[0191] A jet propulsion watercraft according to still another aspect of the present disclosure includes a watercraft body; a battery; an electric propulsion device including an electric motor driven by electricity supplied from the battery, the electric propulsion device applying a propulsive force to the watercraft body; a jet propulsion device including an engine and a jet water flow generator driven by the engine to generate a jet water flow, the jet propulsion device applying a propulsive force to the watercraft body by the jet water flow; a generator that is driven by the engine to generate power and charge the battery; an electric starter that is supplied with power by the battery to start the engine; and a control device that controls the electric propulsion device and the jet propulsion device, in which the control device starts the engine when a condition that the driving of the electric propulsion device is started in a state where a remaining charge amount of the battery is less than a predetermined lower limit determination amount and the engine is being stopped is satisfied.

[0192] According to the present disclosure, by combining the propulsive forces generated by the two propulsion devices, propulsive forces of various directions and sizes can be applied to the watercraft body. Therefore, a degree of freedom of movement of the watercraft body is increased. However, since the electric propulsion device includes the electric motor driven by electricity supplied from the battery, the remaining charge amount of the battery is likely to decrease. When the remaining charge amount of the battery is excessively lowered, it is difficult for the electric propulsion device and the like mounted on the watercraft body to appropriately operate. To cope with this situation, in the jet propulsion watercraft according to the present disclosure, the generator starts to generate power when the driving of the electric propulsion device is started to increase the power consumption amount of the battery in a state where the remaining charge amount of the battery is less than the lower limit determination amount and the engine is being stopped. Therefore, it is possible to prevent the remaining charge amount of the battery from further greatly decreasing from the lower limit determination amount. Therefore, the starter and the engine can be appropriately operated.

Examples

second embodiment

[0122]FIG. 13 is a flowchart corresponding to FIG. 11. FIG. 13 shows control performed by a control device 100 of a PWC1 according to a second embodiment.

[0123]Also in the PWC1 of the second embodiment, the above-described steps S11 to S18 are performed similarly to the first embodiment. On the other hand, in the PWC1 according to the second embodiment, when both of the condition that the battery SOC is equal to or greater than the first SOC and less than the second SOC and the thruster motor 59 is being driven (the condition that the determination in step S19 is YES) and the condition that the engine 5 is being stopped (the condition that the determination in step S20 is YES) are satisfied, the engine 5 is not automatically started, but a notification prompting the driver M to start the engine 5 is given (step S221). Specifically, the control device 100 displays, on the display 15, that the driver M should start the engine 5, to prompt the driver M to start the engine 5. In the exa...

third embodiment

[0127]FIG. 15 is a flowchart corresponding to FIG. 11. FIG. 15 illustrates control performed by a control device 100 of a PWC1 according to a third embodiment. As illustrated in FIG. 15, in the PWC1 of the third embodiment, steps S19 to S22 in the first embodiment illustrated in FIG. 11 are not performed. In addition, in the PWC1 of the third embodiment, although steps S12 to S18 in the first embodiment are performed, implementation conditions thereof are different from those of the first embodiment.

[0128]Specifically, in the PWC1 of the third embodiment, when a condition that the battery SOC is less than a predetermined fourth SOC and the thruster motor 59 is being driven (a condition that the determination in step S401 is YES) is satisfied, step S12 and subsequent steps are performed. Namely, in the PWC1 of the third embodiment, when the battery SOC decreases to less than the fourth SOC in a state where the thruster motor 59 is being driven, or when the driving of the thruster mot...

fourth embodiment

[0131]FIG. 16 is a flowchart corresponding to FIG. 11. FIG. 16 illustrates control performed by a control device 100 of a PWC1 according to a fourth embodiment. As illustrated in FIG. 16, in the PWC1 of the fourth embodiment, steps S12 and S13 and steps S19 to S22 in the first embodiment illustrated in FIG. 11 are not performed.

[0132]Specifically, in the PWC1 according to the fourth embodiment, the driving of the thruster motor 59 is not prohibited (stopped) even when the battery SOC becomes less than the first SOC, and the control to start the engine 5 being stopped (step S15) or the control to raise the engine 5 to the predetermined rotation speed (step S18) is performed. Similarly to the first embodiment, for starting the engine 5 being stopped, the position of the reverse bucket 7 is set to neutral, and the position of the jet nozzle is set to the basic position (step S16). Furthermore, the control for raising the engine 5 to the predetermined rotation speed is performed under a...

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to and the benefit of Japanese Patent Application No. 2025-016546, filed on Feb. 4, 2025, the entire disclosure of which is incorporated herein by reference.FIELD OF INVENTION

[0002] The present disclosure relates to a jet propulsion watercraft.BACKGROUND ART

[0003] As a type of a jet propulsion watercraft, a jet propulsion watercraft recited in US 2013 / 0102206 A is known.

[0004] When a remaining charge amount of a battery mounted on a watercraft body of a jet propulsion watercraft decreases, it becomes difficult to operate an electric component mounted on the watercraft body and supplied with power from the battery.SUMMARY OF THE INVENTION

[0005] The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a jet propulsion watercraft enabling suppression of an excessive decrease in a remaining charge amount of a battery mounted on a watercraft body.

[0006] A jet propulsion watercraft according to an aspect of the present disclosure includes: a watercraft body; a battery; an electric propulsion device including an electric motor driven by electricity supplied from the battery, the electric propulsion device applying a propulsive force to the watercraft body; a jet propulsion device that generates a jet water flow by a power source different from the electric motor and applies a propulsive force to the watercraft body by the jet water flow; and a control device that controls the electric propulsion device and the jet propulsion device, in which the control device controls the electric propulsion device on the basis of a remaining charge amount of the battery.

[0007] A jet propulsion watercraft according to another aspect of the present disclosure includes: a watercraft body; a battery; an electric propulsion device including an electric motor driven by electricity supplied from the battery, the electric propulsion device applying a propulsive force to the watercraft body; a jet propulsion device including an engine and a jet water flow generator driven by the engine to generate a jet water flow, the jet propulsion device applying a propulsive force to the watercraft body by the jet water flow; a generator that is driven by the engine to generate power and charge the battery; an electric starter that is supplied with power by the battery to start the engine; and a control device that controls the electric propulsion device and the jet propulsion device, in which the control device controls the engine to increase a power generation amount of the generator when a remaining charge amount of the battery is less than a predetermined lower limit determination amount.

[0008] A jet propulsion watercraft according to still another aspect of the present disclosure includes a watercraft body; a battery; an electric propulsion device including an electric motor driven by electricity supplied from the battery, the electric propulsion device applying a propulsive force to the watercraft body; a jet propulsion device including an engine and a jet water flow generator driven by the engine to generate a jet water flow, the jet propulsion device applying a propulsive force to the watercraft body by the jet water flow; a generator that is driven by the engine to generate power and charge the battery; an electric starter that is supplied with power by the battery to start the engine; and a control device that controls the electric propulsion device and the jet propulsion device, in which the control device starts the engine when a condition that the driving of the electric propulsion device is started in a state where a remaining charge amount of the battery is less than a predetermined lower limit determination amount and the engine is being stopped is satisfied.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a partially broken side view of a jet propulsion watercraft according to a first embodiment of the present disclosure;

[0010] FIG. 2 is a plan view of the jet propulsion watercraft;

[0011] FIG. 3 is a schematic perspective view illustrating a sub manipulation device provided in the jet propulsion watercraft;

[0012] FIG. 4 is a view illustrating an example of an image displayed on a display provided in the jet propulsion watercraft;

[0013] FIG. 5 is a schematic plan view illustrating a periphery of a jet nozzle of the jet propulsion watercraft;

[0014] FIG. 6 is a schematic side view illustrating the periphery of the jet nozzle of the jet propulsion watercraft;

[0015] FIG. 7 is a plan cross-sectional view schematically illustrating a structure of an electric propulsion device of the jet propulsion watercraft;

[0016] FIG. 8 is a plan view schematically illustrating a propulsive force and the like acting on a watercraft body in a slide pattern;

[0017] FIG. 9 is a functional block diagram illustrating a control system of the jet propulsion watercraft;

[0018] FIG. 10 is a flowchart illustrating a mode decision method by a control device;

[0019] FIG. 11 is a flowchart for explaining battery monitoring control according to the first embodiment;

[0020] FIG. 12 is a flowchart illustrating contents of impeller monitoring control;

[0021] FIG. 13 is a flowchart illustrating contents of battery monitoring control according to a second embodiment;

[0022] FIG. 14 is a view illustrating an example of an image displayed on a display according to the second embodiment;

[0023] FIG. 15 is a flowchart illustrating contents of battery monitoring control according to a third embodiment;

[0024] FIG. 16 is a flowchart illustrating contents of battery monitoring control according to a fourth embodiment; and

[0025] FIG. 17 is a flowchart illustrating contents of battery monitoring control according to a fifth embodiment.DETAILED DESCRIPTION

[0026] Hereinafter, a first embodiment of a jet propulsion watercraft according to the present disclosure will be described with reference to the drawings. In the following description, a front-rear direction of a watercraft body of the jet propulsion watercraft, in detail, a direction connecting a bow and a stern is simply referred to as the front-rear direction, and the bow side is referred to as the front and the stern side is referred to as the rear. Furthermore, a left-right direction of the watercraft body of the jet propulsion watercraft, in detail, a direction orthogonal to the front-rear direction and to a vertical direction is simply referred to as the left-right direction. The front-rear direction and the left-right direction coincide with the front-rear direction and the left-right direction viewed from the driver riding on the jet propulsion watercraft. Direction indications, front, rear, left, and right in the drawings indicate the directions defined as described above.Configuration of Jet Propulsion Watercraft

[0027] FIG. 1 is a partially broken side view of a jet propulsion watercraft 1 according to a first embodiment of the present disclosure, and FIG. 2 is a plan view of the jet propulsion watercraft 1. The jet propulsion watercraft 1 is a watercraft that jets a water flow and moves on the water in reaction to the water flow. In the first embodiment, the jet propulsion watercraft 1 is a riding-type personal watercraft, also called a PWC. For this reason, hereinafter, the jet propulsion watercraft 1 is abbreviated as a PWC1. A line O1 in FIG. 2 is a line passing through the center of the watercraft body 10 of the PWC1 in the left-right direction.

[0028] The PWC1 includes, as a propulsion device that applies a propulsive force to the watercraft body 10, a jet propulsion device 2, and an electric propulsion device 3 that applies a propulsive force different from the jet propulsion device 2 to the watercraft body 10. The jet propulsion device 2 is an engine-type propulsion device and includes an engine 5 as a driving source. The electric propulsion device 3 is an electric-type propulsion device and includes a thruster motor 59 including an electric motor as a drive source. Here, the jet propulsion device 2 generates a propulsive force by driving of the engine 5. Hereinafter, driving / stopping of the jet propulsion device 2 will be simply referred to as driving / stopping of the engine 5 as appropriate. Driving of the thruster motor 59 causes the electric propulsion device 3 to generate a propulsive force. Hereinafter, the driving / stopping of the electric propulsion device 3 is simply referred to as driving / stopping of the thruster motor 59.

[0029] The watercraft body 10 includes a hull 11 and a deck 12 covering an upper side of the hull 11.

[0030] The hull 11 houses the engine 5, the thruster motor 59, and a starter 84. The starter 84 is an electric motor for starting the engine 5. The hull 11 houses a battery 80 that supplies power to various electric apparatuses provided in the watercraft body 10 such as the thruster motor 59 and the starter 84. The hull 11 houses a generator 82 that charges the battery 80.

[0031] A seat 14 is disposed on the deck 12. The seat 14 is a seat on which a driver M who drives the PWC1 is seated. The seat 14 may be a seat for plural persons on which not only the driver M but also fellow passengers can sit, or may be a seat for one person on which only the driver M can sit.

[0032] A steering handle 13 and a shift lever 23 that can be manipulated by the driver M or the like are provided in a front upper part of the deck 12. The steering handle 13 is a manipulator for changing an orientation of a jet nozzle 34 to be described later. The steering handle 13 is provided with an accelerator lever 21 and a start / stop switch 22. The accelerator lever 21 is a manipulator for changing an output of the engine 5. The start / stop switch 22 is a manipulator for switching between start and stop of the engine 5. The shift lever 23 is a manipulator for changing a position of a reverse bucket 7 to be described later.

[0033] A sub manipulation device 25 that can be manipulated by the driver M or the like is provided in the vicinity of the steering handle 13. FIG. 3 is a perspective view illustrating details of the sub manipulation device 25. The sub manipulation device 25 includes a pedestal 26, and a joystick 27, a first joy mode switch SW1, a first direction holding switch SW2, and a first fixed point holding switch SW3 that are supported by the pedestal 26. The joystick 27 is a manipulator for changing a movement direction of the watercraft body 10 when a navigation mode of the watercraft body 10 is a joy mode to be described later. The joystick 27 has a substantially cylindrical shape extending upward from the pedestal 26. As indicated by broken arrows in FIG. 3, the joystick 27 is tiltable in eight directions of front, back, left, right, diagonally front right, diagonally back right, diagonally front left, and diagonally back left from a neutral position. As indicated by chain arrows in FIG. 3, the joystick 27 is turnable rightward and leftward about its central axis in a state of being at the neutral position. The first joy mode switch SW1 is a switch for switching ON / OFF of the joy mode. The first direction holding switch SW2 is a switch for switching ON / OFF of a direction holding mode to be described later which is one of the navigation modes. The first fixed point holding switch SW3 is a switch for switching ON / OFF of a fixed point holding mode to be described later which is one of the navigation modes. The joystick 27 corresponds to a “first manipulator” of the present disclosure.

[0034] A display 15 is provided in front of the steering handle 13. The display 15 is a device that displays various types of information and notifies the driver M or the like of the information. FIG. 4 is a view illustrating an example of an image displayed on the display 15. For example, the display 15 displays a speed D1, a remaining amount of fuel D2, and a bow direction D3 of the watercraft body 10, and a current position D4 of the PWC1, and the like. The display 15 is a touch panel display. Namely, the driver M or the like can perform various input manipulations on the display 15. The display 15 corresponds to a “touch panel” and a “notification unit” of the present disclosure.

[0035] The display 15 displays a second joy mode switch SW11 having the same function as the first joy mode switch SW1 of the sub manipulation device 25. The display 15 displays a second direction holding switch SW12 having the same function as the first direction holding switch SW2 of the sub manipulation device 25. The display 15 displays a second fixed point holding switch SW13 having the same function as the first fixed point holding switch SW3 of the sub manipulation device 25. The display 15 displays a joy switch SW27 having the same function as the joystick 27. The joy switch SW27 corresponds to a “second manipulator” of the present disclosure.Jet Propulsion Device

[0036] The jet propulsion device 2 includes the engine 5, a jet pump 6, and the reverse bucket 7. The reverse bucket 7 corresponds to a “water flow changing device” in the present disclosure.

[0037] The engine 5 is an internal combustion engine, and generates combustion energy by combusting a mixed gas of fuel and air. The engine 5 is, for example, a water-cooled 4-stroke multi-cylinder engine driven using gasoline as fuel. The engine 5 includes a crankshaft 30 extending in the front-rear direction as an output shaft. The starter 84 is an electric motor for starting the engine 5. The starter 84 is coupled to the crankshaft 30 and forces it to rotate.

[0038] The jet pump 6 is disposed in an impeller passage 37. The impeller passage 37 is a passage having a water inlet 36 formed in a bottom surface 11A of the hull 11 as an inlet.

[0039] The jet pump 6 is a pump that generates a jet water flow. The jet pump 6 includes a pump shaft 31, a pump impeller 32, a venturi nozzle 33, and a jet nozzle 34. The pump shaft 31 is coaxially coupled to a rear end of the crankshaft 30. The pump impeller 32 is fixed to the pump shaft 31. When the engine 5 rotates, the pump impeller 32 rotates about its axis to generate a backward water flow. The venturi nozzle 33 and the jet nozzle 34 pressurize and accelerate the water sent from the pump impeller 32 to generate a jet water flow. The jet nozzle 34 has a jet port 35 that opens backward. The generated jet water flow is jetted backward from the jet port 35. This jet water flow applies a propulsive force to the watercraft body 10. The above jet pump 6 corresponds to a “jet water flow generator” of the present disclosure. Hereinafter, a propulsive force by a jet water flow is appropriately referred to as a jet propulsive force.

[0040] The jet nozzle 34 is disposed at a rear end part of the watercraft body 10 and behind a center of gravity G of the PWC1. As a result, the jet water flow is jetted from the rear end part of the watercraft body 10. The center of gravity G of the PWC1 is located, for example, in a region where the sheet 14 is disposed in plan view.

[0041] FIG. 5 is a schematic plan view illustrating a periphery of the jet nozzle 34. The jet nozzle 34 has a substantially cylindrical shape extending in the front-rear direction. The jet nozzle 34 is swingable in the left-right direction as indicated by a broken line, a solid line, and a chain line in FIG. 5. The jet nozzle 34 is of an electric type, and is swinged by a nozzle motor 39 (FIG. 2) including an electric motor. When the jet nozzle 34 swings, an orientation of the jet port 35 and a jet direction of a jet water flow are changed to the left and right.

[0042] Hereinafter, as for a position of the jet nozzle 34, a position where a central axis of the jet nozzle 34 extends straight in the front-rear direction and the jet port 35 opens straight backward as indicated by the solid line in FIG. 5 is referred to as a basic position. In addition, as for a swinging direction of the jet nozzle 34, a case where the jet nozzle 34 swings so that a rear end of the jet nozzle 34 moves to the left as indicated by the broken line from the solid line in FIG. 5 is referred to as swinging to the left, and a case where the jet nozzle swings to the opposite side is referred to as swinging to the right.

[0043] FIG. 6 is a schematic side view illustrating a periphery of the reverse bucket 7. The reverse bucket 7 is basically a device for switching between forward movement, backward movement, and stop of the watercraft body 10. The reverse bucket 7 is turnable in the up-down direction between a reverse position and a forward position. The reverse position is a position where the reverse bucket 7 covers the jet port 35 of the jet nozzle 34 from the back as indicated by a chain line in FIG. 6. The forward position is a position at which the jet port 35 is exposed as indicated by a broken line in FIG. 6. The position of the reverse bucket 7 is switched among the reverse position, the forward position, and a neutral position. The neutral position is an intermediate position between the forward position and the reverse position as indicated by a solid line in FIG. 6. The reverse bucket 7 is of an electric type, and is turned by a bucket motor 49 including an electric motor.

[0044] The reverse bucket 7 includes a main body wall 41 that covers the jet port 35 from the back in a state of being at the reverse position. The reverse bucket 7 includes a left wall part 42 and a right wall part 43 respectively extending forward from a left edge and a right edge of the main body wall 41 in a state of being at the reverse position. Through holes 44 and 45 are formed in the left wall part 42 and the right wall part 43, respectively.

[0045] When the reverse bucket 7 is at the forward position, the jet water flow jetted from the jet port 35 goes backward without being hindered by the reverse bucket 7. Accordingly, in a state where the reverse bucket 7 is at the forward position, a forward jet propulsive force is applied to the watercraft body 10.

[0046] In a state where the reverse bucket 7 is at the reverse position, the jet water flow jetted backward from the jet port 35 has an orientation changed forward by collision with the main body wall 41, and is jetted forward from the left and right through holes 44 and 45. As a result, in the state where the reverse bucket 7 is at the reverse position, a backward jet propulsive force is applied to the watercraft body 10.

[0047] In a state where the reverse bucket 7 is at the neutral position, the jet water flow jetted from the jet port 35 is divided into the left and right and advances to the left and right outer sides through the through holes 44 and 45. When amounts of water of the jet water flows passing through the left and right through holes 44 and 45 are equal to each other, the propulsive forces of the left and right jet water flows cancel each other, so that a jet propulsive force applied to the watercraft body 10 becomes substantially zero. Namely, the watercraft body 10 stops. On the other hand, when the amounts of water on the left and right sides are different, a propulsive force of one of the left and right jet water flows increases, so that a rightward or leftward jet propulsive force including substantially no front-rear direction component is applied to the watercraft body 10.

[0048] By combining the position of the jet nozzle 34 and the position of the reverse bucket 7, an orientation of a jet propulsive force applied to the watercraft body 10 can be changed in almost all directions. Specifically, when the position of the jet nozzle 34 is changed in a state where the reverse bucket 7 is at the forward position, the jet propulsive force changes its left and right orientations in a state of having a forward component. When the position of the jet nozzle 34 is changed in a state where the reverse bucket 7 is at the reverse position, the jet propulsive force changes its right and left orientations in a state of having a backward component. Furthermore, when the position of the jet nozzle 34 is changed in a state where the reverse bucket 7 is at the neutral position, the jet propulsive force changes its right and left orientations in a state of having no front-rear direction component. As described above, when the amounts of water of the jet water flow passing through the two through holes 44 and 45 are equal, the jet propulsive force becomes substantially zero.

[0049] As the orientation of the jet propulsive force is changeable in substantially all directions, the watercraft body 10 is movable in substantially all directions. However, the jet propulsive force is applied to the rear end part of the watercraft body 10. Therefore, when only the jet propulsive force is applied to the watercraft body 10, the watercraft body 10 moves with a change in an orientation of the bow except for a pattern of moving straight forward and straight backward.Generator

[0050] The generator 82 is driven by the engine 5 to generate power. The generator 82 is coupled to the crankshaft 30 with its rotor coaxial with the crankshaft 30. The generator 82 generates power by rotational driving of the rotor by the crankshaft 30. The generator 82 is connected to the battery 80, and electricity generated by the generator 82 is stored in the battery 80. In the first embodiment, the generator 82 rotates integrally with the engine 5 to generate power. Namely, the generator 82 is always rotationally driven to generate power during rotation of the engine.Electric Propulsion Device

[0051] FIG. 7 is a plan cross-sectional view schematically showing a structure of the electric propulsion device 3. The electric propulsion device 3 generates an auxiliary water flow directed outward in the left-right direction from a front part of the watercraft body 10. This auxiliary water flow applies a propulsive force to the watercraft body 10. The electric propulsion device 3 is a so-called electric thruster. In addition to the thruster motor 59, the electric propulsion device 3 includes a propeller shaft 51 extending left and right, an impeller 52 fixed to the propeller shaft 51, and a gear mechanism 53. The electric propulsion device 3 is disposed ahead of the center of gravity G of the PWC1. Hereinafter, the propulsive force by the auxiliary water flow is appropriately referred to as an auxiliary propulsive force.

[0052] The watercraft body 10 includes a water passage 55 at a position corresponding to the electric propulsion device 3. The water passage 55 is a passage penetrating a front part of the hull 11 in the left-right direction. The thruster motor 59 is disposed inside the hull 11. The propeller shaft 51, the impeller 52, and the gear mechanism 53 are housed inside the water passage 55. The propeller shaft 51 and the impeller 52 are driven by the thruster motor 59 to rotate about an axis extending in the left-right direction. Specifically, rotation input from the thruster motor 59 to the gear mechanism 53 is redirected by 90 degrees and then transmitted to the impeller 52. Rotation of the impeller 52 causes the water introduced into the water passage 55 to be jetted from one end (a left-side opening 55A or a right-side opening 55B) of the water passage 55. As a result, an auxiliary water flow, which is a water flow along the left-right direction, is generated.

[0053] The thruster motor 59 can rotate forward and backward. Orientation of the auxiliary water flow is switched by switching a rotation direction of the thruster motor 59. For example, when the thruster motor 59 rotates forward, a leftward auxiliary water flow is generated as indicated by an arrow Y51. The leftward auxiliary water flow applies a rightward auxiliary propulsive force to the watercraft body 10 as indicated by an arrow Y52. When the thruster motor 59 reversely rotates, a rightward auxiliary water flow is generated as indicated by an arrow Y53 in FIG. 7. The rightward auxiliary water flow applies a leftward auxiliary propulsive force to the watercraft body 10 as indicated by an arrow Y54.

[0054] The auxiliary water flow is generated at a front part of the PWC1. As a result, when the rightward auxiliary propulsive force (Y52) is applied to the front part of the watercraft body 10, a rightward, i.e., a clockwise yaw moment (Y55) is applied to the watercraft body 10. Therefore, when the jet propulsive force is not applied to the watercraft body 10 at this time, the watercraft body 10 turns clockwise without substantially moving in the front-rear direction as indicated by a solid line to a broken line in FIG. 7. In addition, when the leftward auxiliary propulsive force (Y54) is applied to the front part of the watercraft body 10, a counterclockwise yaw moment (Y56) is applied to the watercraft body 10. Therefore, when the jet propulsive force is not applied to the watercraft body 10 at this time, the watercraft body 10 turns counterclockwise without substantially moving in the front-rear direction as indicated by the solid line to a chain line in FIG. 7.Slide Movement

[0055] With the jet propulsion device 2 and the electric propulsion device 3 configured as described above, the watercraft body 10 is also movable in directions different from forward and backward while maintaining the orientation of the bow. Specifically, the reason why the orientation of the bow changes when the watercraft body 10 moves upon receiving a jet propulsive force is that a yaw moment caused by the jet propulsive force is applied to the rear end part of the watercraft body 10. Therefore, setting orientations and magnitudes of the jet propulsive force and the auxiliary propulsive force in the left-right direction to be the same enables the yaw moment caused by the jet propulsive force to be canceled by a yaw moment caused by the auxiliary propulsive force, thereby maintaining the orientation of the bow. Here, as described above, the watercraft body 10 is movable substantially in all directions upon receiving the jet propulsive force. Therefore, by setting orientations and magnitudes of the two propulsive forces in a manner as described above for each direction, the watercraft body 10 can be moved in almost all directions while maintaining the orientation of the bow. Straight forward movement of the watercraft body 10 while maintaining the orientation of the bow is realized by stopping the thruster motor 59, setting the reverse bucket 7 to the forward position, and setting the jet nozzle 34 to the basic position. Straight backward movement of the watercraft body 10 while maintaining the orientation of the bow is realized by stopping the thruster motor 59, setting the reverse bucket 7 to the reverse position, and setting the jet nozzle 34 to the basic position. Hereinafter, movement while the orientation of the bow of the watercraft body 10 is maintained is appropriately referred to as slide movement.

[0056] FIG. 8 is a view schematically illustrating a force applied to the watercraft body 10 during slide movement. FIG. 8 illustrates a state of the watercraft body 10 when the watercraft body 10 slides diagonally front right as an example of the slide movement.

[0057] In the example of FIG. 8, a jet water flow Y11 is jetted diagonally back left. As a result, a diagonally front right jet propulsive force F11 is applied to the watercraft body 10. In addition, a counterclockwise yaw moment YM11 is applied to the watercraft body 10 by a rightward component F11A of the jet propulsive force F11. In addition, in the example of FIG. 8, a leftward auxiliary water flow Y12 is also generated. As a result, a rightward auxiliary propulsive force F12 is applied to the watercraft body 10. A clockwise yaw moment YM12 is also applied to the watercraft body 10. In the example of FIG. 8, a magnitude of each of the propulsive forces F11 and F12, i.e., a strength of each of the water flows Y11 and Y12 is set such that the two yaw moments YM11 and YM12 cancel each other out. As a result, the watercraft body 10 receives a resultant force F13 of the two propulsive forces F11 and F12 in a state where the yawing is suppressed, and moves in a direction of the resultant force F13, i.e., diagonally front right as indicated by an arrow Y19. As described above, at the time of sliding the watercraft body 10, it is necessary to set the strength of each water flow so that the two yaw moments cancel each other.Control System

[0058] A control system of the PWC1 will be described. A control device 100 that outputs control signals to various devices mounted on the watercraft body 10 to control these devices is mounted on the watercraft body 10. FIG. 9 is a functional block diagram illustrating the control system of the PWC1. The control device 100 is a device including, as a main part, a microcomputer including a processor (CPU) that performs calculation and memories such as a ROM and a RAM.

[0059] The control device 100 receives signals from the steering handle 13, the accelerator lever 21, the start / stop switch 22, and the shift lever 23. The control device 100 receives signals, respectively from the joystick 27, the first joy mode switch SW1, the first direction holding switch SW2, and the first fixed point holding switch SW3 provided in the sub manipulation device 25. The control device 100 receives signals from the joy switch SW27, the second joy mode switch SW11, the second direction holding switch SW12, and the second fixed point holding switch SW13 on the display 15. In detail, these manipulators have built in sensors for detecting manipulation states thereof, and the control device 100 receives signals from these sensors.

[0060] An inertial measurement unit (IMU) 92, a speed sensor 94, and a battery sensor 96 are mounted on the watercraft body 10. The control device 100 receives signals from the IMU92, the speed sensor 94, and the battery sensor 96. The IMU92 is an inertial measurement device in which a three-axis gyro sensor and a three-axis acceleration sensor are combined. The IMU92 detects angular velocities around three axes orthogonal to each other and accelerations in three axis directions in the watercraft body 10. The IMU92 can calculate a bow direction of the watercraft body 10 on the basis of the angular velocity or the like, and also functions as a device for detecting the bow direction of the watercraft body 10. The speed sensor 94 detects a navigation speed of the watercraft body 10. The battery sensor 96 is a sensor for calculating a remaining charge amount of the battery 80. Specifically, the battery sensor 96 detects a battery current which is a current flowing in and out of the battery 80.

[0061] The control device 100 controls elements such as a fuel injection device and a spark plug provided for the engine 5 to control the output of the engine 5, and thus, a momentum of a jet water flow and a strength of a jet propulsive force. Here, as described above, the generator 82 rotates integrally with the engine 5. As a result, when the output of the engine 5 increases or decreases, a power generation amount of the generator 82 also increases or decreases substantially in proportion to the increase or decrease. The control device 100 controls the position of the jet nozzle 34 and the reverse bucket 7 to control the orientation of the jet propulsive force. The control device 100 controls an output and a rotation direction of the thruster motor 59 to control a momentum and an orientation of the auxiliary water flow, and thus control a strength and an orientation of the auxiliary propulsive force.

[0062] The control device 100 controls the starter 84 to switch between driving and stopping of the starter 84. The control device 100 controls display contents of the display 15. In the example of the image illustrated in FIG. 4, the bow direction D3 of the watercraft body 10 displayed on the display 15 is a direction specified by the IMU92. The velocity D1 of the watercraft body 10 displayed on the display 15 is a value detected by the velocity sensor 94. For example, the control device 100 outputs a control signal to the display 15 so that these pieces of information are displayed.

[0063] The control device 100 functionally includes a position specifying unit 101, a determination unit 102, a navigation control unit 103, a battery monitoring unit 104, and an impeller monitoring unit 105.

[0064] The position specifying unit 101 is a module that controls the position of the PWC1. The position specifying unit 101 has a GPS function and specifies a current position of the PWC1 on the basis of a signal from an artificial satellite. In the first embodiment, a GPS receiver is provided in the vicinity of the bow, and a position in the vicinity of the bow of the watercraft body 10 is specified. The current position D4 of the PWC1 displayed on the display 15 is the position specified by the position specifying unit 101.

[0065] The determination unit 102 is a module that performs various determinations regarding control of the PWC1. The navigation control unit 103 is a module that performs various calculations on the basis of a determination result of the determination unit 102 and the like and controls the jet propulsion device 2 and the like.Navigation Control

[0066] Control related to navigation of the watercraft body 10 performed by the control device 100 will be described. In the PWC1, the fixed point holding mode, the direction holding mode, the joy mode, and a jet navigation mode are set as navigation modes of the watercraft body 10. The fixed point holding mode is a mode for keeping the watercraft body 10 within a predetermined range. The direction holding mode is a mode for keeping the direction of the watercraft body 10 constant. The joy mode is a mode of moving the watercraft body 10 on the basis of manipulation on the joystick 27 or the joy switch SW27. The jet navigation mode is a mode of causing the watercraft body 10 to navigate only by the jet propulsive force on the basis of manipulation on the steering handle 13 or the like.

[0067] The determination unit 102 decides in which mode the watercraft body 10 is to be navigated. FIG. 10 is a flowchart illustrating a mode decision method by the determination unit 102.

[0068] As illustrated in FIG. 10, the determination unit 102 first determines whether the first fixed point holding switch SW3 or the second fixed point holding switch SW13 has been turned ON or not (step S1). In a case where the determination is YES and the fixed point holding switch SW3 or SW13 is turned ON, the determination unit 102 decides the navigation mode of the watercraft body 10 as the fixed point holding mode (step S2). When the navigation mode of the watercraft body 10 is decided to be the fixed point holding mode, the navigation control unit 103 executes fixed point holding control.

[0069] In a case where the determination in step S1 is NO, i.e., when the fixed point holding switches SW3 and SW13 are not turned ON, the determination unit 102 determines whether the first direction holding switch SW2 or the second direction holding switch SW12 is turned ON or not (step S3). When the determination is YES and the direction holding switch SW2 or SW12 is turned ON, the determination unit 102 decides the navigation mode of the watercraft body 10 as the direction holding mode (step S4). When the navigation mode of the watercraft body 10 is decided to be the direction holding mode, the navigation control unit 103 executes direction holding control.

[0070] In a case where the determination in step S3 is NO, i.e., when the direction holding switches SW2 and SW12 are not turned ON, the determination unit 102 determines whether the first joy mode switch SW1 or the second joy mode switch SW11 is turned ON or not (step S5). In case where the determination is YES and the joy mode switch SW1 or SW11 is turned ON, the determination unit 102 decides the navigation mode of the watercraft body 10 as the joy mode (step S6). When the navigation mode of the watercraft body 10 is decided to be the joy mode, the navigation control unit 103 executes joy mode control.

[0071] In a case where the determination in step S5 is NO, i.e., when the joy mode switches SW1 and SW11 are not turned ON, the determination unit 102 decides the navigation mode of the watercraft body 10 as the jet navigation mode (step S7). When the navigation mode of the watercraft body 10 is decided to be the jet navigation mode, the navigation control unit 103 executes jet navigation control.

[0072] Next, control contents of each mode will be described.Fixed Point Holding Control

[0073] At the start of the fixed point holding control, i.e., when the fixed point holding switch SW3 or SW13 is switched from OFF to ON, the navigation control unit 103 stops the engine 5 and the thruster motor 59. In a case where they are already stopped, the stopped state is maintained. The determination unit 102 sets a position of the PWC1 specified by the position specifying unit 101 at the time of the switching to an anchor point and stores the anchor point. In addition, the determination unit 102 sets an area in which a separation distance from the anchor point is equal to or less than a predetermined reference value to an anchor area and stores the anchor area.

[0074] Until the fixed point holding switch SW3 or SW13 that has been turned ON is turned OFF, the determination unit 102 continuously determines whether or not the current position of the PWC1 has moved to the outside of the anchor area. When it is determined that the current position of the PWC1 has moved to the outside of the anchor area, the navigation control unit 103 drives the engine 5 while maintaining the stop of the thruster motor 59. In addition, the navigation control unit 103 controls the reverse bucket 7 and the jet nozzle 34 so that the watercraft body 10 moves toward the anchor point. Then, when the position of the PWC1 nears the anchor point, the navigation control unit 103 stops the engine 5 again. The engine 5 is not necessarily stopped when the fixed point holding switch SW3 or SW13 is switched from OFF to ON and when the position of the PWC1 returns to the vicinity of the anchor point. However, in a case of driving the engine 5, the reverse bucket 7 is set to the neutral position and the jet nozzle 34 is set to the basic position.Direction Holding Control

[0075] At the start of the direction holding control, i.e., when the direction holding switch SW2 or SW12 is switched from OFF to ON, the determination unit 102 sets a bow direction detected by the IMU92 at the time of this switching to a reference direction and stores the reference direction.

[0076] Until the direction holding switch SW2 or SW12 that has been turned ON is turned OFF, the determination unit 102 continuously determines whether or not a current bow direction of the PWC1 has deviated from the reference direction. When it is determined that the current bow direction of the PWC1 has deviated from the reference direction, the navigation control unit 103 drives the engine 5 and the thruster motor 59. In a case where they are already driven, the driven state is maintained. In addition, the navigation control unit 103 controls the reverse bucket 7, the jet nozzle 34, and the thruster motor 59 so that the watercraft body 10 turns in a direction opposite to the deviated direction of the bow direction.Joy Mode Control

[0077] During the execution of the joy mode control, the navigation control unit 103 controls the jet propulsion device 2 and the electric propulsion device 3 on the basis of manipulation on the joystick 27 or the joy switch SW27. As illustrated in FIG. 4, the joy switch SW27 includes arrows respectively indicating eight tilting directions of the joystick 27 and arrows respectively indicating two turning directions of the same. In the first embodiment, the control device 100 recognizes that manipulation of touching each arrow included in the joy switch SW27, i.e., manipulation of touching each arrow with a finger of the driver M or the like is the same as tilting or turning manipulation of the joystick 27 in a direction corresponding to the touched arrow. In the following description of the joy mode control, a case where the joystick 27 is used as a manipulator will be described as a representative.

[0078] When the joystick 27 is manipulated to tilt forward from the neutral position, the navigation control unit 103 controls the propulsion devices 2 and 3 such that the watercraft body 10 slides forward. When the joystick 27 is manipulated to tilt backward from the neutral position, the navigation control unit 103 controls the propulsion devices 2 and 3 such that the watercraft body 10 slides backward. As described above, the forward and backward slide movement of the watercraft body 10 is realized by stopping the thruster motor 59 and driving the engine 5 to jet a jet water flow forward or backward.

[0079] When the joystick 27 is manipulated to tilt leftward from the neutral position, the navigation control unit 103 controls the propulsion devices 2 and 3 such that the watercraft body 10 slides leftward. When the joystick 27 is manipulated to tilt rightward from the neutral position, the navigation control unit 103 controls the propulsion devices 2 and 3 such that the watercraft body 10 slides rightward. When the joystick 27 is manipulated to tilt diagonally front right from the neutral position, the navigation control unit 103 controls the propulsion devices 2 and 3 such that the watercraft body 10 slides diagonally front right by 45 degrees. When the joystick 27 is manipulated to tilt diagonally front left from the neutral position, the navigation control unit 103 controls the propulsion devices 2 and 3 such that the watercraft body 10 slides diagonally front left by 45 degrees. When the joystick 27 is manipulated to tilt diagonally back right from the neutral position, the navigation control unit 103 controls the propulsion devices 2 and 3 such that the watercraft body 10 slides diagonally back right by 45 degrees. When the joystick 27 is manipulated to tilt diagonally back left from the neutral position, the navigation control unit 103 controls the propulsion devices 2 and 3 such that the watercraft body 10 slides diagonally back left by 45 degrees.

[0080] As described above, the slide movement of the watercraft body 10 in the oblique direction is realized by driving the thruster motor 59 and the engine 5. Furthermore, the slide movement of the watercraft body 10 in the oblique direction is realized by controlling the thruster motor 59, the engine 5, the reverse bucket 7, and the jet nozzle 34 such that the yaw moment caused by the propulsive force of the jet water flow and the yaw moment caused by the propulsive force of the auxiliary water flow cancel each other and a resultant force of these propulsive forces is in the oblique direction.

[0081] When the joystick 27 at the neutral position is manipulated to turn rightward about its central axis, the navigation control unit 103 controls the propulsion devices 2 and 3 so that the watercraft body 10 turns rightward, i.e., clockwise. When the joystick 27 at the neutral position is manipulated to turn leftward about its central axis, the navigation control unit 103 controls the propulsion devices 2 and 3 so that the watercraft body 10 turns leftward, i.e., counterclockwise. In the first embodiment, when the joystick 27 is manipulated to turn, the engine 5 is stopped while the thruster motor 59 is driven, so that the turning of the watercraft body 10 is realized only by the auxiliary propulsive force.

[0082] The slide movement or turning of the watercraft body 10 and the control for realizing the slide movement or turning are performed only while the joystick 27 or the joy switch SW27 is manipulated.Jet Navigation Control

[0083] In a case where the engine 5 is stopped when the jet navigation control is started, the navigation control unit 103 drives (starts) the engine 5. On the other hand, when the thruster motor 59 is being driven, the navigation control unit 103 stops the thruster motor 59.

[0084] In the jet navigation control, the navigation control unit 103 controls the jet propulsion device 2 on the basis of the manipulation on the steering handle 13, the accelerator lever 21, and the shift lever 23. Specifically, the navigation control unit 103 switches the position of the reverse bucket 7 on the basis of the manipulation on the shift lever 23. The navigation control unit 103 changes the position of the jet nozzle 34 on the basis of the manipulation on the steering handle 13. The navigation control unit 103 controls a throttle valve, a fuel injection device, and the like provided in the engine 5 on the basis of manipulation on the accelerator lever 21 to increase or decrease the output of the engine 5.Battery Monitoring Control

[0085] The battery monitoring unit 104 is a module that controls the propulsion devices 2 and 3 on the basis of a battery SOC or the like. The control of the propulsion devices 2 and 3 by the battery monitoring unit 104 is prioritized over the control of the propulsion devices 2 and 3 set for each navigation mode described above. Battery monitoring control performed by the battery monitoring unit 104 will be described with reference to FIG. 11. FIG. 11 is a flowchart for explaining the battery monitoring control. Each step illustrated in FIG. 11 is performed every predetermined time.

[0086] First, the battery monitoring unit 104 determines whether the battery SOC is less than a predetermined first SOC or not (step S11). The battery monitoring unit 104 calculates a battery SOC, which is a state of charge (SOC) of the battery 80, as a remaining charge amount of the battery 80 on the basis of a current value of the battery sensor 96. For example, the battery monitoring unit 104 calculates the battery SOC by integrating a battery current detected by the battery sensor 96. The first SOC is set in advance on the basis of an experiment or the like and stored in the control device 100. The first SOC is set to a value higher than the battery SOC at which the starter 84 cannot start the engine 5. In the first embodiment, the first SOC is set to a value slightly higher than an upper limit value of the battery SOC at which the starter 84 cannot start the engine 5. The first SOC corresponds to a“lower limit determination amount” of the present disclosure.

[0087] In a case where the determination in step S11 is YES and the battery SOC is less than the first SOC, the battery monitoring unit 104 prohibits driving of the thruster motor 59 (step S12). When the thruster motor 59 is driven, the battery monitoring unit 104 stops the thruster motor 59. Here, there is a case where the thruster motor 59 is driven in the direction holding mode and the joy mode among the four navigation modes. As a result, the battery monitoring unit 104 prohibits navigation of the watercraft body 10 in the direction holding mode and the joy mode (step S13). When the watercraft body 10 is navigating in the direction holding mode or the joy mode, the navigation of the watercraft body 10 in these modes is stopped.

[0088] After step S13, the battery monitoring unit 104 determines whether the engine 5 is stopped or not (step S14). The battery monitoring unit 104 makes this determination on the basis of a signal from a sensor or the like that detects a rotation speed of the engine 5. When the determination in step S14 is YES and the engine 5 is being stopped, the battery monitoring unit 104 drives, i.e., starts the engine 5 (step S15). Furthermore, the battery monitoring unit 104 sets a bucket position to the neutral position (N) and sets a nozzle position to the basic position (step S16), and ends the processing. In a state where the bucket position is at the neutral position and the nozzle position is at the basic position, the jet water flow is equally divided into the left and right, so that the jet propulsive force applied to the watercraft body 10 becomes zero and the watercraft body 10 stops.

[0089] In the first embodiment, steps S12, S13, S15, S16, and S18 once executed are continued until the battery SOC becomes equal to or greater than a second SOC greater than the first SOC. When the battery SOC becomes equal to or greater than the second SOC, the control device 100 returns to the processing of step S1 (FIG. 10). Namely, once the battery SOC decreases to less than the first SOC, the driving of the thruster motor 59 and the execution of the direction holding mode and the joy mode are prohibited until the battery SOC becomes equal to or greater than the second SOC. Once the battery SOC decreases to less than the first SOC, the engine 5 is driven at least until the battery SOC becomes equal to or greater than the second SOC. The second SOC is set to a value greater than the first SOC in advance and stored in the control device 100. The second SOC corresponds to a “determination amount” of the present disclosure.

[0090] As described above, when the engine 5 rotates, the generator 82 is rotationally driven to generate power. Therefore, when the engine 5 is started in step S15, power generation by the generator 82 is started.

[0091] On the other hand, when the determination in step S14 is NO and the engine 5 is being driven, the battery monitoring unit 104 determines whether or not a rotation-increase permission condition that the bucket position is at the neutral position (N) and the nozzle position is at the basic position is satisfied (step S17).

[0092] When the determination in step S17 is YES and the rotation-increase permission condition is satisfied, the battery monitoring unit 104 increases the engine rotation speed to a predetermined rotation speed (step S18), and ends the processing (returns to step S11). Specifically, the battery monitoring unit 104 sets, as a target rotation speed, the rotation speed higher, by a preset difference, than an engine rotation speed at the timing when the determination in step S11 is switched from NO to YES, and controls the throttle valve, the fuel injection device, and the like of the engine 5 so that the engine rotation speed becomes the target rotation speed. When the engine rotation speed increases, a rotation amount of the generator 82 also increases, and the power generation amount of the generator 82 increases. On the other hand, when the determination in step S17 is NO and the rotation-increase permission condition is not satisfied, the battery monitoring unit 104 ends the processing as it is (returns to step S11).

[0093] When the determination in step S11 is NO and the battery SOC is equal to or greater than the first SOC, the battery monitoring unit 104 determines whether a condition that the battery SOC is less than the second SOC and the thruster motor 59 is being driven is satisfied or not (step S19).

[0094] When the determination in step S19 is YES and the condition is satisfied, the battery monitoring unit 104 determines whether the engine 5 is being stopped or not as in step S14 (step S20).

[0095] When the determination in step S20 is YES and the engine 5 is being stopped, the battery monitoring unit 104 drives, i.e., starts the engine 5 (step S21). As a result, power generation by the generator 82 is started. Furthermore, the battery monitoring unit 104 sets the bucket position to the neutral position (N) and sets the nozzle position to the basic position (step S22), and ends the processing (returns to step S11). A condition that the thruster motor 59 is being driven and the engine 5 is being stopped is satisfied when the watercraft body 10 is subjected to the turning control while the navigation mode is set to the joy mode, or when the navigation mode is set to the direction holding mode and the direction holding control is performed. Namely, when one of the two controls is performed and the battery SOC decreases to less than the second SOC while the thruster motor 59 is being driven, or when one of the two controls is started to start the driving of the thruster motor 59 while the battery SOC is less than the second SOC, steps S21 and S22 are performed. In the first embodiment, at this time, the control is continued while steps S21 and S22 are performed. Specifically, the watercraft body 10 is turned by the thruster motor 59 while the engine 5 is driven in a state where the bucket position is at the neutral position and the nozzle position is at the basic position. Alternatively, the bow direction of the watercraft body 10 is changed by the thruster motor 59 while the engine 5 is driven in a state where the bucket position is at the neutral position and the nozzle position is at the basic position.

[0096] On the other hand, when the determination in step S19 is NO and the battery SOC is equal to or greater than the second SOC or the thruster motor 59 is stopped, and when the determination in step S19 is YES while the determination in step S20 is NO and the engine 5 is being driven, the battery monitoring unit 104 ends the processing as it is (returns to step S11). When the determination in step S20 is NO, the engine 5 and the generator 82 have already been driven, and the generator 82 continues to generate power.

[0097] As described in the foregoing, the battery monitoring unit 104 controls the thruster motor 59, the engine 5, the reverse bucket 7, and the jet nozzle 34 in preference to the control corresponding to the navigation mode, according to the battery SOC and a driving state of the thruster motor 59.Impeller Monitoring Control

[0098] The impeller monitoring unit 105 is a module that performs control related to abnormality determination of the impeller 52 of the electric propulsion device 3. Impeller monitoring control performed by the impeller monitoring unit 105 will be described with reference to FIG. 12. FIG. 12 is a flowchart for explaining the impeller monitoring control. Each step shown in FIG. 12 is performed every predetermined time. In the following description of the impeller monitoring control and FIG. 12, a case where the joystick 27, as a representative of the joystick 27 and the joy switch SW27, is used as a manipulator will be described.

[0099] First, the impeller monitoring unit 105 determines whether or not a condition that the joystick 27 is manipulated during navigation in the joy mode is satisfied (step S31). This determination is made on the basis of a determination result of the determination unit 102 and a signal from the joystick 27.

[0100] In a case where the determination in step S31 is NO, and the navigation is not being performed in the joy mode or the joystick 27 is not being manipulated, the impeller monitoring unit 105 ends the processing as it is (returns to step S31). On the other hand, in a case where the determination in step S31 is YES, and the joystick 27 is being manipulated during navigation in the joy mode, the impeller monitoring unit 105 determines whether or not the joystick 27 is manipulated to tilt forward or backward from the neutral position (step S32).

[0101] In a case where the determination in step S32 is YES and the joystick 27 is manipulated to tilt forward or backward from the neutral position, the impeller monitoring unit 105 ends the processing as it is (returns to step S31).

[0102] On the other hand, in a case where the determination in step S32 is NO and manipulation other than the above is performed on the joystick 27, the impeller monitoring unit 105 determines whether or not a manipulation amount of the joystick 27 is equal to or more than a predetermined manipulation amount for determination (step S33). The manipulation amount for use in the determination in step S33 is a duration of the manipulation on the joystick 27. Specifically, it is a time from the timing at which the manipulation currently being performed on the joystick 27 is started to the present. The manipulation amount for determination is preset and stored in the control device 100.

[0103] In a case where the determination in step S33 is NO and the manipulation amount of the joystick 27 is less than the manipulation amount for determination, the impeller monitoring unit 105 ends the processing as it is (returns to step S31).

[0104] On the other hand, in a case where the determination in step S33 is YES and the manipulation amount of the joystick 27 is equal to or more than the manipulation amount for determination, the impeller monitoring unit 105 then determines whether or not a watercraft body movement amount is less than a predetermined movement amount for determination (step S34). The watercraft body movement amount is a distance that the watercraft body 10 has moved from the timing when the manipulation currently performed on the joystick 27 has been started to the present. In the first embodiment, a movement distance of the bow is used as the watercraft body movement amount. The impeller monitoring unit 105 calculates the watercraft body movement amount on the basis of a position of the watercraft body 10 and the like specified by the position specifying unit 101. The movement amount for determination is preset and stored in the control device 100. The movement amount for determination is set to a value smaller than a minimum movement amount of the watercraft body 10 realized when the manipulation amount of the joystick 27 is set to the manipulation amount for determination during navigation in the joy mode while the electric propulsion device 3 is normal.

[0105] In a case where the determination in step S34 is NO and the watercraft body movement amount is equal to or more than the movement amount for determination, the impeller monitoring unit 105 ends the processing as it is.

[0106] On the other hand, when the determination in step S34 is YES and the watercraft body movement amount is less than the movement amount for determination, the impeller monitoring unit 105 determines that the impeller 52 is abnormal (step S35). Namely, when a movement amount of the watercraft body 10 is suppressed to be less than the movement amount for determination although the joystick 27 is manipulated until its manipulation amount becomes equal to or more than the manipulation amount for determination, it is considered that the impeller 52 is not normally rotated. Accordingly, when the determination in step S35 is YES, the impeller monitoring unit 105 determines that the impeller 52 is not normally rotating, i.e., is abnormal.

[0107] When determining that the impeller 52 is abnormal, the impeller monitoring unit 105 then determines whether the manipulation of the joystick 27 has ended or not (step S36). When the determination in step S36 is NO and the manipulation of the joystick 27 has not ended, the impeller monitoring unit 105 repeats step S36. Namely, the impeller monitoring unit 105 waits for the end of the manipulation of the joystick 27 and then performs the next step S37. When the manipulation of the joystick 27 ends, the thruster motor 59 is stopped.

[0108] In step S37, the impeller monitoring unit 105 stops the thruster motor 59 after reversely rotating the thruster motor for a predetermined time, and ends the processing (returns to step S31). Specifically, the impeller monitoring unit 105 causes the thruster motor 59 to rotate in a direction opposite to the rotation direction of the thruster motor 59 performed immediately before. As a result, the impeller 52 rotates in a direction opposite to the immediately preceding rotation direction. Namely, in step S37, the thruster motor 59 is driven such that the rotation direction of the impeller 52 is reversed. In addition, the impeller monitoring unit 105 stops the thruster motor 59 when a predetermined time has elapsed since the start of the reverse rotation of the thruster motor 59. The predetermined time is preset and stored in the control device 100.Operation and Effects

[0109] As described in the foregoing, in the PWC1 according to the first embodiment, as devices that apply a propulsive force to the watercraft body 10, the jet propulsion device 2 using the engine 5 that generates a jet water flow as a driving source and the electric propulsion device 3 using the thruster motor 59 that generates an auxiliary water flow as a driving source are mounted on the watercraft body 10. Therefore, by combining the propulsive forces generated by the propulsion devices 2 and 3, it is possible to apply propulsive forces of various directions and sizes to the watercraft body 10. Therefore, a degree of freedom of movement of the watercraft body is increased. For example, as described above, the slide movement of the watercraft body 10 is enabled by the combination of the two propulsive forces.

[0110] However, the thruster motor 59 is an electric motor supplied with power from the battery 80. Therefore, depending on a use situation of the thruster motor 59, the battery SOC may be excessively lowered, so that it may be difficult to various electric apparatuses may have a difficulty in appropriately operating. In the first embodiment, power is supplied to the starter 84 by the battery 80. Therefore, when the battery SOC becomes excessively small, there is a possibility that the engine 5 cannot be appropriately started by the starter 84.

[0111] To cope with this situation, in the PWC1 of the first embodiment, when the battery SOC becomes less than the first SOC, the driving of the thruster motor 59 is prohibited, and the power consumption by the thruster motor 59 is stopped. Therefore, it is possible to prevent the battery SOC from greatly decreasing from the first SOC, i.e., to prevent the battery SOC from excessively decreasing. Therefore, it is possible to ensure appropriate operation of various electric apparatuses and start of the engine 5.

[0112] In particular, in the PWC1 of the first embodiment, the first SOC is set to a value slightly higher than the upper limit value of the battery SOC at which the engine 5 cannot be started. Therefore, it is possible to prevent the starter 84 from being unable to start the engine 5 due to a shortage of the battery SOC.

[0113] Furthermore, in the PWC1 of the first embodiment, when the battery SOC becomes less than the first SOC, the engine 5 is controlled so that the power generation amount of the generator 82 increases. Specifically, when the battery SOC becomes less than the first SOC while the engine 5 is stopped, the engine 5 is started and power generation by the generator 82 is started. Namely, the power generation amount of the generator 82 is increased from zero. Therefore, the battery SOC can be increased again.

[0114] Here, when the engine 5 is automatically started as the battery SOC becomes less than the first SOC, if the jet water flow generated by the engine 5 is jetted from the front side or the rear side of the watercraft body 10, the watercraft body 10 moves forward or backward, and the driver M may feel uncomfortable.

[0115] To cope with this situation, in the PWC1 of the first embodiment, at the time of automatically starting the engine 5 as the battery SOC becomes less than the first SOC, the reverse bucket 7 is set to the neutral position, and the jet water flow is jetted separately to the left and right. Therefore, it is possible to suppress the watercraft body 10 from making forward or backward movement unexpected by the driver M. In particular, in the PWC1 of the first embodiment, the reverse bucket 7 is set to the neutral position, and the jet nozzle 34 is set to the basic position. Therefore, since the jet water flow is equally divided in the left-right direction, it is possible to prevent the watercraft body 10 from making movement unexpected by the driver M.

[0116] Furthermore, in the PWC1 of the first embodiment, when the battery SOC becomes less than the first SOC during driving of the engine 5, the rotation speed of the engine 5 is increased, and the power generation amount of the generator 82 is increased. Therefore, the battery SOC can be increased early.

[0117] The control for increasing the engine speed is performed when the position of the reverse bucket 7 is at the neutral position and the position of the jet nozzle 34 is at the basic position. Therefore, it is possible to prevent the watercraft body 10 from making movement unexpected by the driver M as the engine speed increases.

[0118] In addition, in the PWC1 of the first embodiment, the engine 5 is started when a condition that while the engine is stopped, the thruster motor 59 is driven and the battery SOC is decreased to less than the second SOC is satisfied, or when a condition that the driving of the thruster motor 59 is started while the engine is stopped and the battery SOC is less than the second SOC is satisfied. Therefore, it is possible to prevent the battery SOC from further decreasing from the second SOC as power is consumed by the thruster motor 59. In addition, when the engine 5 is started as the above conditions are satisfied, the reverse bucket 7 is placed at the neutral position, and the jet water flow is jetted separately to the left and right. Therefore, it is possible to suppress the watercraft body 10 from making forward or backward movement unexpected by the driver M. Moreover, the jet nozzle 34 is set to the basic position. Therefore, since the jet water flow is equally divided in the left-right direction, it is possible to more reliably prevent the watercraft body 10 from making movement unexpected by the driver M.

[0119] Furthermore, in the PWC1 of the first embodiment, when it is determined that the impeller 52 of the electric propulsion device 3 is abnormal, the rotation direction of the thruster motor 59 is made opposite to the immediately preceding direction, so that the rotation of the impeller 52 is reversed. Therefore, when an abnormality occurs in the impeller 52 due to entanglement of algae or the like, the algae or the like entangled in the impeller 52 can be removed.

[0120] Also in the PWC1 of the first embodiment, the impeller 52 is determined to be abnormal when the manipulation amount of the joystick 27 or the joy switch SW27 for manipulating the thruster motor 59 is equal to or more than the manipulation amount for determination and the movement amount of the watercraft body 10 is less than the movement amount for determination. Therefore, an abnormality of the impeller 52 can be determined without providing a sensor or the like that detects a rotation state of the impeller 52.

[0121] In addition, in the PWC1 of the first embodiment, two manipulators, the joystick 27 and the joy switch SW27, are provided as manipulators in the joy mode for driving the thruster motor 59 to navigate the watercraft body 10, i.e., manipulators for manipulating the thruster motor 59. Therefore, convenience is improved. In particular, the joy switch SW27 is a switch displayed on the touch panel display 15, and the thruster motor 59 can be easily manipulated by touch manipulation of the joy switch SW27.Second Embodiment

[0122] FIG. 13 is a flowchart corresponding to FIG. 11. FIG. 13 shows control performed by a control device 100 of a PWC1 according to a second embodiment.

[0123] Also in the PWC1 of the second embodiment, the above-described steps S11 to S18 are performed similarly to the first embodiment. On the other hand, in the PWC1 according to the second embodiment, when both of the condition that the battery SOC is equal to or greater than the first SOC and less than the second SOC and the thruster motor 59 is being driven (the condition that the determination in step S19 is YES) and the condition that the engine 5 is being stopped (the condition that the determination in step S20 is YES) are satisfied, the engine 5 is not automatically started, but a notification prompting the driver M to start the engine 5 is given (step S221). Specifically, the control device 100 displays, on the display 15, that the driver M should start the engine 5, to prompt the driver M to start the engine 5. In the example of FIG. 14, when the above condition is satisfied, the control device 100 displays a wording D10“WARNING! Start engine” on the display 15. For example, the control device 100 continues this display until the engine 5 is started.

[0124] Configurations other than the above configuration are similar to those of the first embodiment, and description of other configurations is omitted.

[0125] According to the PWC1 of the second embodiment, it is possible to prompt the driver M to start the engine 5 when the battery SOC is low. Therefore, the decrease in the battery SOC can be suppressed by the power generation of the generator 82 accompanying the driving of the engine 5. Furthermore, by starting the engine 5 by the driver M himself / herself, it is possible to prevent the driver M from feeling uncomfortable as the engine 5 starts. Note that effects based on the same configuration included in the second embodiment as that of the first embodiment can also be obtained in the second embodiment.

[0126] Here, in the second embodiment, steps S11 to S18 illustrated in FIG. 13 may be omitted. Namely, the controls of stopping the thruster motor 59, starting the engine 5, and increasing the rotation speed of the engine 5 as the battery SOC becomes less than the first SOC may be omitted. In a case where these are omitted, when the battery SOC is less than a predetermined value (second SOC), and the thruster motor 59 is being driven and the engine is stopped, only a notification for prompting the start of the engine is made, and automatic control of the thruster motor 59 and the engine 5 by the control device 100 is not performed.Third Embodiment

[0127] FIG. 15 is a flowchart corresponding to FIG. 11. FIG. 15 illustrates control performed by a control device 100 of a PWC1 according to a third embodiment. As illustrated in FIG. 15, in the PWC1 of the third embodiment, steps S19 to S22 in the first embodiment illustrated in FIG. 11 are not performed. In addition, in the PWC1 of the third embodiment, although steps S12 to S18 in the first embodiment are performed, implementation conditions thereof are different from those of the first embodiment.

[0128] Specifically, in the PWC1 of the third embodiment, when a condition that the battery SOC is less than a predetermined fourth SOC and the thruster motor 59 is being driven (a condition that the determination in step S401 is YES) is satisfied, step S12 and subsequent steps are performed. Namely, in the PWC1 of the third embodiment, when the battery SOC decreases to less than the fourth SOC in a state where the thruster motor 59 is being driven, or when the driving of the thruster motor 59 is started in a state where the battery SOC is less than the fourth SOC, the driving of the thruster motor 59 is prohibited (stopped) (step S12), and navigation in the direction holding mode and the joy mode is prohibited (stopped) (step S13). In a case where the engine is being stopped (when the determination in step S14 is YES), the engine 5 is started (step S15), the position of the reverse bucket 7 is set to neutral, and the position of the jet nozzle is set to the basic position (step S16). In a case where the engine is being driven when the above condition is satisfied, and the position of the reverse bucket 7 is neutral, and the position of the jet nozzle is at the basic position, the rotation speed of the engine 5 is increased to the predetermined rotation speed (step S18). Furthermore, in the PWC1 of the third embodiment, when a condition that the battery SOC is less than the predetermined fourth SOC and the thruster motor 59 is being driven is not satisfied, the processing is ended as it is. In the third embodiment, steps S12, S13, S15, S16, and S18 once performed are continued until the battery SOC reaches a predetermined value larger than the fourth SOC. The fourth SOC is set to a value higher than the battery SOC at which the starter 84 cannot start the engine 5. In the third embodiment, the fourth SOC is set to a value slightly higher than the upper limit value of the battery SOC at which the starter 84 cannot start the engine 5. The fourth SOC corresponds to the “determination amount” of the present disclosure.

[0129] Configurations other than the above configuration are similar to those of the first embodiment, and description of other configurations is omitted.

[0130] The PWC1 of the third embodiment also prevents the thruster motor 59 from consuming power in a state where the battery SOC is low. Therefore, it is possible to prevent the battery SOC from being excessively lowered. In addition, also in the PWC1 of the third embodiment, a power generation opportunity of the generator 82 accompanying the driving of the engine 5 and a power generation amount increase opportunity accompanying an increase in the rotation speed of the engine 5 increase. Accordingly, it is also possible to prevent the battery SOC from being excessively lowered. Note that effects based on the same configuration included in the third embodiment as that of the first embodiment can also be obtained in the third embodiment.Fourth Embodiment

[0131] FIG. 16 is a flowchart corresponding to FIG. 11. FIG. 16 illustrates control performed by a control device 100 of a PWC1 according to a fourth embodiment. As illustrated in FIG. 16, in the PWC1 of the fourth embodiment, steps S12 and S13 and steps S19 to S22 in the first embodiment illustrated in FIG. 11 are not performed.

[0132] Specifically, in the PWC1 according to the fourth embodiment, the driving of the thruster motor 59 is not prohibited (stopped) even when the battery SOC becomes less than the first SOC, and the control to start the engine 5 being stopped (step S15) or the control to raise the engine 5 to the predetermined rotation speed (step S18) is performed. Similarly to the first embodiment, for starting the engine 5 being stopped, the position of the reverse bucket 7 is set to neutral, and the position of the jet nozzle is set to the basic position (step S16). Furthermore, the control for raising the engine 5 to the predetermined rotation speed is performed under a condition that the position of the reverse bucket 7 is neutral and the position of the jet nozzle is the basic position. In the fourth embodiment, steps SS15, S16, and S18 once performed are continued until the battery SOC reaches a predetermined value larger than the first SOC. In addition, in the fourth embodiment, when the battery SOC is equal to or greater than the first SOC, the processing is ended as it is without starting the engine 5 or the like.

[0133] Configurations other than the above configuration are similar to those of the first embodiment, and description of other configurations is omitted.

[0134] Also with the PWC1 of the fourth embodiment, when the battery SOC is low, it is possible to prevent the battery SOC from being excessively lowered because a power generation opportunity of the generator 82 accompanying the driving of the engine 5 and a power generation amount increase opportunity accompanying an increase in the rotation speed of the engine 5 increase. Note that effects based on the same configuration included in the fourth embodiment as that of the first embodiment can also be obtained in the fourth embodiment.Fifth Embodiment

[0135] FIG. 17 is a flowchart corresponding to FIG. 16. FIG. 17 illustrates control performed by a control device 100 of a PWC1 according to a fifth embodiment. As illustrated in FIG. 17, in the PWC1 of the fifth embodiment, steps S14 to S18 are performed similarly to the fourth embodiment illustrated in FIG. 16. On the other hand, in the PWC1 of the fifth embodiment, the conditions under which steps S14 to S18 are performed are different from those of the fourth embodiment.

[0136] Specifically, in the PWC1 of the fifth embodiment, when a condition that the battery SOC is less than the first SOC and the thruster motor 59 is being driven (a condition that determination in step S601 is YES) is satisfied, step S14 and subsequent steps are performed. Namely, in the PWC1 of the fifth embodiment, when the battery SOC decreases to less than the first SOC in a state where the thruster motor 59 is being driven, or when the driving of the thruster motor 59 is started in a state where the battery SOC is less than the first SOC, starting the engine 5 (step S15) and increasing the rotation speed of the engine 5 are performed (step S18).

[0137] Configurations other than the above configuration are similar to those of the fourth embodiment, and description of other configurations is omitted.

[0138] The PWC1 of the fifth embodiment also prevents a decrease in the battery SOC due to power consumption by the thruster motor 59 when the thruster motor 59 is driven in a state where the battery SOC is low. Therefore, it is possible to prevent the battery SOC from being excessively lowered. Note that effects based on the same configuration included in the fifth embodiment as that of the fourth embodiment can also be obtained in the fifth embodiment.Other Modifications

[0139] In the first embodiment, steps S19 to S22 illustrated in FIG. 11 may be omitted.

[0140] In the first to third embodiments, the case where the driving of the thruster motor 59 is prohibited in step S12 illustrated in FIGS. 11, 13, and 15 has been described. Alternatively, the output of the thruster motor 59 may be reduced to suppress the driving of the thruster motor 59. In this configuration, step S13 may be omitted.

[0141] In the first to third embodiments, the control for starting the stopped engine 5 and the control for increasing the rotation speed of the engine 5 may be omitted. Namely, steps S14 to S18 illustrated in FIGS. 11, 13, and 15 may be omitted. Steps S14 to S16 may be omitted. Steps S14, S17, and S18 may be omitted.

[0142] The description has been made of a case in which in step S19 of the first and second embodiments, step S401 of the third embodiment, and step S601 of the sixth embodiment, it is determined whether or not the condition that the battery SOC is less than the predetermined value and the thruster motor 59 is being driven is satisfied, and when the condition is satisfied, stop of the thruster motor 59, start of the engine, and the like are performed. Alternatively, as the above condition, a condition that the driving of the thruster motor 59 is started in a state where the battery SOC is less than a predetermined value may be used.

[0143] In each of the above embodiments, the case has been described in which, when step S15 is performed, i.e., when the engine 5 that has been stopped is forcibly started, step S16 is performed to set the reverse bucket 7 to the neutral position and set the position of the jet nozzle 34 to the basic position. However, the control of changing these positions may be omitted. Namely, step S16 may be omitted. Furthermore, the control of setting the position of the jet nozzle 34 to the basic position may be omitted, and only the control of setting the reverse bucket 7 to the neutral position may be performed. Even when the jet nozzle 34 is displaced from the basic position, the forward or backward movement of the watercraft body 10 is suppressed as long as the jet water flow is distributed to the left and right by the reverse bucket 7. A specific device for changing the orientation of the jet water flow is not limited to the jet nozzle 34 and to the reverse bucket 7 described above.

[0144] In the second embodiment, the case has been described in which the predetermined wording is displayed on the display 15 to prompt the driver M to start the engine 5. However, the notification method for prompting the start of the engine 5 is not limited to the display of wording on the display 15. For example, a notification for prompting the start of the engine 5 may be made by a method of displaying a symbol or the like on the display 15 or a method of generating sound from a speaker provided on the watercraft body 10.

[0145] In each of the above embodiments, the description has been made with the case where it is determined whether the impeller 52 is abnormal or not on the basis of the manipulation amount of the joystick 27 or the joy switch SW27 and the movement amount of the watercraft body 10. However, the method for determining whether the impeller 52 is abnormal or not is not limited thereto.

[0146] Furthermore, the manipulator for manipulating the thruster motor 59 is not limited to the joystick 27 and the joy switch SW27. For example, instead of or in addition to the joy switch SW27, a manipulator provided in a communication unit capable of communicating with the control device 100 may be used as a manipulator for manipulating the thruster motor 59.

[0147] In each of the above embodiments, the description has been made of the case where power is supplied from the common battery 80 to various electric apparatuses including the thruster motor 59 and the starter 84. Alternatively, the watercraft body 10 may be provided with a battery that supplies power to the thruster motor 59 alone separately from the battery that supplies power to other electric apparatuses including the starter 84. Hereinafter, a battery that supplies power to the thruster motor 59 alone is referred to as a thruster battery, and a battery that supplies power to other electric apparatuses is referred to as a main battery. In a case where the thruster battery and the main battery are separately provided, a configuration realized by replacing the battery 80 in each of the above embodiments with the thruster battery may be adopted as the configuration of the PWC1.

[0148] For example, as in steps S11 and S12 illustrated in FIG. 11, the driving of the thruster motor 59 may be prohibited (stopped) when the SOC of the thruster battery becomes less than a predetermined value. In the case where the thruster battery and the main battery are separately provided, when the SOC of the thruster battery becomes less than the predetermined value, a crew member of the watercraft body 10 may be notified that the SOC of the thruster battery is low by the display 15 or the like.

[0149] When assuming that a capacity of the thruster battery in a fully charged state is a full charge capacity, an initial capacity of the thruster battery is an initial capacity, an amount of electricity consumed by the thruster motor 59 is a thruster consumption amount, and an amount of electricity charged from the generator 82 to the thruster battery is an ACG charge amount, the SOC of the thruster battery can be calculated by the formula “(initial capacity−thruster consumption amount+ACG charge amount) / full charge capacity”. Here, the initial capacity is a discharge capacity of the thruster battery before the thruster battery is charged by the generator 82 as when the thruster battery is first mounted on the watercraft body 10, and can be obtained by detecting a voltage of the thruster battery. The thruster consumption amount can also be obtained from the specifications of the thruster motor 59. Namely, a preset value can be used as the thruster consumption amount. In addition, the ACG charge amount can be obtained from the rotation speed of the generator 82 or the like.

[0150] The functionality of the elements disclosed herein may be implemented using one or more circuitry or processing circuitry which includes general purpose processors, special purpose processors, integrated circuits, ASICs (“Application Specific Integrated Circuits”), FPGAs (“Field Programmable Gate Arrays”) and / or conventional circuitry. The functionality of the elements disclosed herein may be implemented using one or more circuitry or processing circuitry which includes combinations of general purpose processors, special purpose processors, integrated circuits, ASICs, FPGAs, or conventional circuitry. The one or more circuitry or processing circuitry is programmed, using one or more programs stored together or individually in one or more memories, or otherwise configured to perform the disclosed functionality. Processors are considered processing circuitry or circuitry as they include transistors and other circuitry therein. The processor may be a programmed processor which executes a program stored in a memory. In the disclosure, the circuitry, units, or means are hardware that carry out or are programmed to perform the recited functionality, alone or in combination with one another. The hardware may be any hardware disclosed herein which is programmed or configured to carry out the recited functionality.

[0151] There is a memory that stores a computer program which includes computer instructions. The computer instructions provide the logic and routines that enable the hardware to perform the method disclosed herein. The hardware includes, e.g., processing circuitry or circuitry. The computer program can be implemented in known formats as a computer-readable storage medium, a computer program product, a memory device, a record medium such as a CD-ROM or DVD, and / or the memory of a FPGAs or ASICs.Conclusion

[0152] The above embodiments and modifications thereof include the following disclosure.

[0153] A jet propulsion watercraft according to an aspect of the present disclosure includes: a watercraft body; a battery; an electric propulsion device including an electric motor driven by electricity supplied from the battery, the electric propulsion device applying a propulsive force to the watercraft body; a jet propulsion device that generates a jet water flow by a power source different from the electric motor and applies a propulsive force to the watercraft body by the jet water flow; and a control device that controls the electric propulsion device and the jet propulsion device, in which the control device controls the electric propulsion device on the basis of a remaining charge amount of the battery.

[0154] According to the present disclosure, by combining the propulsive forces generated by the two propulsion devices, propulsive forces of various directions and sizes can be applied to the watercraft body. Therefore, a degree of freedom of movement of the watercraft body is increased. However, since the electric propulsion device includes the electric motor driven by electricity supplied from the battery, the remaining charge amount of the battery is likely to decrease. When the remaining charge amount of the battery is excessively lowered, it is difficult for an electric apparatus such as the electric propulsion device mounted on the watercraft body to appropriately operate. To cope with this situation, in the jet propulsion watercraft according to the present disclosure, since the electric propulsion device is controlled on the basis of the remaining charge amount of the battery, an amount of power consumed by the electric propulsion device can be adjusted according to the remaining charge amount of the battery, so that the remaining charge amount of the battery can be prevented from becoming excessively small.

[0155] Preferably, the control device suppresses driving of the electric propulsion device when a remaining charge amount of the battery is less than a predetermined lower limit determination amount.

[0156] According to this mode, it is possible to prevent the remaining charge amount of the battery from further greatly decreasing from the lower limit determination amount by the driving of the electric propulsion device.

[0157] Preferably, the power source of the jet propulsion device includes an engine that generates combustion energy, the jet propulsion watercraft including: a generator that is driven by the engine to generate power and charge the battery; and an electric starter that is powered by the battery to start the engine.

[0158] According to this mode, the engine can apply a propulsive force to the watercraft body, and the engine can drive the generator to charge the battery. Furthermore, in the jet propulsion watercraft according to the present disclosure, the remaining charge amount of the battery is prevented from becoming excessively small as described above. Therefore, the starter supplied with power from the battery is provided to enable starting of the engine while preventing the starter and thus the engine from not being appropriately driven due to a small remaining charge amount of the battery.

[0159] Preferably, the control device suppresses driving of the electric propulsion device when a remaining charge amount of the battery is less than a predetermined lower limit determination amount.

[0160] According to this mode, it is possible to prevent the remaining charge amount of the battery from further greatly decreasing from the lower limit determination amount by the driving of the electric propulsion device. Therefore, it is possible to prevent the starter and the engine from becoming undrivable as the remaining charge amount of the battery runs short.

[0161] Preferably, the control device controls the engine to increase a power generation amount of the generator when a remaining charge amount of the battery is less than a predetermined lower limit determination amount.

[0162] According to this mode, the battery can be charged when the remaining charge amount of the battery is less than the lower limit determination amount.

[0163] Preferably, the control device starts the engine when the engine is stopped and the remaining charge amount of the battery is less than the lower limit determination amount.

[0164] According to this mode, when the remaining charge amount of the battery is less than the lower limit determination amount, it is possible to start power generation by the generator and charge the battery.

[0165] Preferably, the jet propulsion device includes a water flow changing device capable of changing an orientation of the jet water flow, and the control device controls the water flow changing device so that the orientation of the jet water flow is in both left and right directions of the watercraft body when the engine is started as the remaining charge amount of the battery is less than the lower limit determination amount while the engine is stopped.

[0166] According to this mode, when the engine is automatically started as the remaining charge amount of the battery is less than the lower limit determination amount, it is possible to suppress the watercraft body from making forward or backward movement unexpected by the driver.

[0167] Preferably, the lower limit determination amount is set to a value higher than a capacity of the battery by which the engine cannot be started by the starter.

[0168] According to this mode, the engine can be more reliably started by the starter.

[0169] Preferably, the control device starts the engine when a condition that the driving of the electric propulsion device is started in a state where a remaining charge amount of the battery is less than a predetermined determination amount and the engine is being stopped is satisfied.

[0170] According to this mode, when the electric propulsion device starts to be driven and the remaining charge amount of the battery may further decrease from the determination amount, power generation by the generator can be started. Therefore, it is possible to prevent the remaining charge amount of the battery from greatly decreasing from the determination amount.

[0171] Preferably, the jet propulsion device includes a water flow changing device capable of changing an orientation of the jet water flow, and the control device controls the water flow changing device so that an orientation of the jet water flow is in both left and right directions of the watercraft body when the engine is started as the condition is satisfied.

[0172] According to this mode, when the engine is automatically started as the remaining charge amount of the battery is less than the determination amount, it is possible to suppress the watercraft body from making forward or backward movement not intended by the driver.

[0173] Preferably, a notification unit that notifies a crew member of the watercraft body is provided, and the control device causes the notification unit to notify the crew member of the watercraft body to start the engine when a condition that the driving of the electric propulsion device is started in a state where a remaining charge amount of the battery is less than a predetermined determination amount and the engine is being stopped is satisfied.

[0174] According to this mode, the engine can be started by a crew member such as a driver when the remaining battery charge amount is low. Therefore, further reduction of the remaining battery charge amount can be suppressed by the power generation of the generator accompanying the driving of the engine. In addition, since the driver starts the engine by himself / herself, it is possible to prevent the driver from feeling uncomfortable about the start of the engine as compared with a case where the engine is automatically started.

[0175] Preferably, the determination amount is set to a value higher than a capacity of the battery at which the engine cannot be started by the starter.

[0176] According to this mode, the engine can be more reliably started by the starter.

[0177] Preferably, the electric propulsion device includes an impeller that is rotationally driven by the electric motor to generate the propulsive force, and the control device controls the electric motor such that a rotation direction of the impeller is reversed when an abnormality occurs in the impeller.

[0178] According to this mode, when an abnormality occurs in the impeller due to entanglement of algae or the like, the algae or the like entangled in the impeller can be removed.

[0179] Preferably, a motor manipulator that manipulates the electric motor is provided, and the control device determines whether an abnormality has occurred in the impeller or not on the basis of a manipulation amount of the motor manipulator and a movement amount of the watercraft body.

[0180] According to this mode, an abnormality of the impeller can be determined without providing a sensor or the like that detects the rotation state of the impeller.

[0181] Preferably, there are provided a first manipulator that is provided on the watercraft body so as to be tiltable in a plurality of directions and that manipulates the electric propulsion device, and a second manipulator that is provided separately from the first manipulator and is capable of manipulating the electric propulsion device.

[0182] According to this mode, the driver can select a manipulator to be used from the first manipulator and the second manipulator. Therefore, convenience is improved.

[0183] Preferably, the second manipulator is a touch panel provided on the watercraft body.

[0184] According to this mode, the electric propulsion device can be manipulated by touch manipulation on the touch panel.

[0185] A jet propulsion watercraft according to another aspect of the present disclosure includes: a watercraft body; a battery; an electric propulsion device including an electric motor driven by electricity supplied from the battery, the electric propulsion device applying a propulsive force to the watercraft body; a jet propulsion device including an engine and a jet water flow generator driven by the engine to generate a jet water flow, the jet propulsion device applying a propulsive force to the watercraft body by the jet water flow; a generator that is driven by the engine to generate power and charge the battery; an electric starter that is supplied with power by the battery to start the engine; and a control device that controls the electric propulsion device and the jet propulsion device, in which the control device controls the engine to increase a power generation amount of the generator when a remaining charge amount of the battery is less than a predetermined lower limit determination amount.

[0186] According to the present disclosure, by combining the propulsive forces generated by the two propulsion devices, propulsive forces of various directions and sizes can be applied to the watercraft body. Therefore, a degree of freedom of movement of the watercraft body is increased. However, since the electric propulsion device includes the electric motor driven by electricity supplied from the battery, the remaining charge amount of the battery is likely to decrease. When the remaining charge amount of the battery is excessively lowered, it is difficult for an electric apparatus such as the electric propulsion device mounted on the watercraft body to appropriately operate. By contrast, in the jet propulsion watercraft according to the present disclosure, when the remaining charge amount of the battery becomes less than the lower limit determination amount, the power generation amount of the generator is increased. Therefore, it is possible to prevent the remaining charge amount of the battery from further greatly decreasing from the lower limit determination amount. Therefore, the starter and the engine can be appropriately operated.

[0187] Preferably, the control device starts the engine when the engine is being stopped and the remaining charge amount of the battery is less than the lower limit determination amount.

[0188] According to this mode, when the remaining charge amount of the battery is less than the lower limit determination amount, it is possible to start power generation by the generator and charge the battery.

[0189] Preferably, the jet propulsion device includes a water flow changing device capable of changing an orientation of the jet water flow, and the control device controls the water flow changing device so that the orientation of the jet water flow is in both left and right directions of the watercraft body when the engine is started as the remaining charge amount of the battery is less than the lower limit determination amount while the engine is stopped.

[0190] According to this mode, when the engine is automatically started as the remaining charge amount of the battery is less than the lower limit determination amount, it is possible to suppress the watercraft body from making forward or backward movement unexpected by the driver.

[0191] A jet propulsion watercraft according to still another aspect of the present disclosure includes a watercraft body; a battery; an electric propulsion device including an electric motor driven by electricity supplied from the battery, the electric propulsion device applying a propulsive force to the watercraft body; a jet propulsion device including an engine and a jet water flow generator driven by the engine to generate a jet water flow, the jet propulsion device applying a propulsive force to the watercraft body by the jet water flow; a generator that is driven by the engine to generate power and charge the battery; an electric starter that is supplied with power by the battery to start the engine; and a control device that controls the electric propulsion device and the jet propulsion device, in which the control device starts the engine when a condition that the driving of the electric propulsion device is started in a state where a remaining charge amount of the battery is less than a predetermined lower limit determination amount and the engine is being stopped is satisfied.

[0192] According to the present disclosure, by combining the propulsive forces generated by the two propulsion devices, propulsive forces of various directions and sizes can be applied to the watercraft body. Therefore, a degree of freedom of movement of the watercraft body is increased. However, since the electric propulsion device includes the electric motor driven by electricity supplied from the battery, the remaining charge amount of the battery is likely to decrease. When the remaining charge amount of the battery is excessively lowered, it is difficult for the electric propulsion device and the like mounted on the watercraft body to appropriately operate. To cope with this situation, in the jet propulsion watercraft according to the present disclosure, the generator starts to generate power when the driving of the electric propulsion device is started to increase the power consumption amount of the battery in a state where the remaining charge amount of the battery is less than the lower limit determination amount and the engine is being stopped. Therefore, it is possible to prevent the remaining charge amount of the battery from further greatly decreasing from the lower limit determination amount. Therefore, the starter and the engine can be appropriately operated.

Examples

second embodiment

[0122]FIG. 13 is a flowchart corresponding to FIG. 11. FIG. 13 shows control performed by a control device 100 of a PWC1 according to a second embodiment.

[0123]Also in the PWC1 of the second embodiment, the above-described steps S11 to S18 are performed similarly to the first embodiment. On the other hand, in the PWC1 according to the second embodiment, when both of the condition that the battery SOC is equal to or greater than the first SOC and less than the second SOC and the thruster motor 59 is being driven (the condition that the determination in step S19 is YES) and the condition that the engine 5 is being stopped (the condition that the determination in step S20 is YES) are satisfied, the engine 5 is not automatically started, but a notification prompting the driver M to start the engine 5 is given (step S221). Specifically, the control device 100 displays, on the display 15, that the driver M should start the engine 5, to prompt the driver M to start the engine 5. In the exa...

third embodiment

[0127]FIG. 15 is a flowchart corresponding to FIG. 11. FIG. 15 illustrates control performed by a control device 100 of a PWC1 according to a third embodiment. As illustrated in FIG. 15, in the PWC1 of the third embodiment, steps S19 to S22 in the first embodiment illustrated in FIG. 11 are not performed. In addition, in the PWC1 of the third embodiment, although steps S12 to S18 in the first embodiment are performed, implementation conditions thereof are different from those of the first embodiment.

[0128]Specifically, in the PWC1 of the third embodiment, when a condition that the battery SOC is less than a predetermined fourth SOC and the thruster motor 59 is being driven (a condition that the determination in step S401 is YES) is satisfied, step S12 and subsequent steps are performed. Namely, in the PWC1 of the third embodiment, when the battery SOC decreases to less than the fourth SOC in a state where the thruster motor 59 is being driven, or when the driving of the thruster mot...

fourth embodiment

[0131]FIG. 16 is a flowchart corresponding to FIG. 11. FIG. 16 illustrates control performed by a control device 100 of a PWC1 according to a fourth embodiment. As illustrated in FIG. 16, in the PWC1 of the fourth embodiment, steps S12 and S13 and steps S19 to S22 in the first embodiment illustrated in FIG. 11 are not performed.

[0132]Specifically, in the PWC1 according to the fourth embodiment, the driving of the thruster motor 59 is not prohibited (stopped) even when the battery SOC becomes less than the first SOC, and the control to start the engine 5 being stopped (step S15) or the control to raise the engine 5 to the predetermined rotation speed (step S18) is performed. Similarly to the first embodiment, for starting the engine 5 being stopped, the position of the reverse bucket 7 is set to neutral, and the position of the jet nozzle is set to the basic position (step S16). Furthermore, the control for raising the engine 5 to the predetermined rotation speed is performed under a...

Claims

1. A jet propulsion watercraft comprising;a watercraft body;a battery;an electric propulsion device including an electric motor driven by electricity supplied from the battery, the electric propulsion device applying a propulsive force to the watercraft body;a jet propulsion device that generates a jet water flow by a power source different from the electric motor and applies a propulsive force to the watercraft body by the jet water flow; anda control device that controls the electric propulsion device and the jet propulsion device, wherein the control device controls the electric propulsion device on the basis of a remaining charge amount of the battery.

2. The jet propulsion watercraft according to claim 1, wherein the control device suppresses driving of the electric propulsion device when a remaining charge amount of the battery is less than a predetermined lower limit determination amount.

3. The jet propulsion watercraft according to claim 1, whereinthe power source of the jet propulsion device includes an engine that generates combustion energy, the jet propulsion watercraft including:a generator that is driven by the engine to generate power and charge the battery; andan electric starter that is powered by the battery to start the engine.

4. The jet propulsion watercraft according to claim 3, wherein the control device suppresses driving of the electric propulsion device when a remaining charge amount of the battery is less than a predetermined lower limit determination amount.

5. The jet propulsion watercraft according to claim 3, wherein the control device controls the engine to increase a power generation amount of the generator when a remaining charge amount of the battery is less than a predetermined lower limit determination amount.

6. The jet propulsion watercraft according to claim 5, wherein the control device starts the engine when the engine is being stopped and the remaining charge amount of the battery is less than the lower limit determination amount.

7. The jet propulsion watercraft according to claim 6, whereinthe jet propulsion device includes a water flow changing device capable of changing an orientation of the jet water flow, andthe control device controls the water flow changing device so that the orientation of the jet water flow is in both left and right directions of the watercraft body when the engine is started as the remaining charge amount of the battery is less than the lower limit determination amount while the engine is stopped.

8. The jet propulsion watercraft according to claim 4, wherein the lower limit determination amount is set to a value higher than a capacity of the battery by which the engine cannot be started by the starter.

9. The jet propulsion watercraft according to claim 3, wherein the control device starts the engine when a condition that the driving of the electric propulsion device is started in a state where a remaining charge amount of the battery is less than a predetermined determination amount and the engine is being stopped is satisfied.

10. The jet propulsion watercraft according to claim 9, whereinthe jet propulsion device includes a water flow changing device capable of changing an orientation of the jet water flow, andthe control device controls the water flow changing device so that an orientation of the jet water flow is in both left and right directions of the watercraft body when the engine is started as the condition is satisfied.

11. The jet propulsion watercraft according to claim 3, further comprising:a notification unit that notifies a crew member of the watercraft body,wherein the control device causes the notification unit to notify the crew member of the watercraft body to start the engine when a condition that the driving of the electric propulsion device is started in a state where a remaining charge amount of the battery is less than a predetermined determination amount and the engine is being stopped is satisfied.

12. The jet propulsion watercraft according to claim 9, wherein the determination amount is set to a value higher than a capacity of the battery at which the engine cannot be started by the starter.

13. The jet propulsion watercraft according to claim 1, whereinthe electric propulsion device includes an impeller that is rotationally driven by the electric motor to generate the propulsive force, andthe control device controls the electric motor such that a rotation direction of the impeller is reversed when an abnormality occurs in the impeller.

14. The jet propulsion watercraft according to claim 13, further comprising:a motor manipulator that manipulates the electric motor,wherein the control device determines whether an abnormality has occurred in the impeller or not on the basis of a manipulation amount of the motor manipulator and a movement amount of the watercraft body.

15. The jet propulsion watercraft according to claim 1, further comprising:a first manipulator that is provided on the watercraft body so as to be tiltable in a plurality of directions and that manipulates the electric propulsion device; anda second manipulator that is provided separately from the first manipulator and is capable of manipulating the electric propulsion device.

16. The jet propulsion watercraft according to claim 15, wherein the second manipulator is a touch panel provided on the watercraft body.

17. A jet propulsion watercraft comprising;a watercraft body;a battery;an electric propulsion device including an electric motor driven by electricity supplied from the battery, the electric propulsion device applying a propulsive force to the watercraft body;a jet propulsion device including an engine and a jet water flow generator driven by the engine to generate a jet water flow, the jet propulsion device applying a propulsive force to the watercraft body by the jet water flow;a generator that is driven by the engine to generate power and charge the battery;an electric starter that is supplied with power by the battery to start the engine; anda control device that controls the electric propulsion device and the jet propulsion device, the control device controlling the engine to increase a power generation amount of the generator when a remaining charge amount of the battery is less than a predetermined lower limit determination amount.

18. The jet propulsion watercraft according to claim 17, wherein the control device starts the engine when the engine is being stopped and the remaining charge amount of the battery is less than the lower limit determination amount.

19. The jet propulsion watercraft according to claim 18, whereinthe jet propulsion device includes a water flow changing device capable of changing an orientation of the jet water flow, andthe control device controls the water flow changing device so that the orientation of the jet water flow is in both left and right directions of the watercraft body when the engine is started as the remaining charge amount of the battery is less than the lower limit determination amount while the engine is stopped.

20. A jet propulsion watercraft comprising;a watercraft body;a battery;an electric propulsion device including an electric motor driven by electricity supplied from the battery, the electric propulsion device applying a propulsive force to the watercraft body;a jet propulsion device including an engine and a jet water flow generator driven by the engine to generate a jet water flow, the jet propulsion device applying a propulsive force to the watercraft body by the jet water flow;a generator that is driven by the engine to generate power and charge the battery;an electric starter that is supplied with power by the battery to start the engine; anda control device that controls the electric propulsion device and the jet propulsion device, the control device starting the engine when a condition that the driving of the electric propulsion device is started in a state where a remaining charge amount of the battery is less than a predetermined lower limit determination amount and the engine is being stopped is satisfied.

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