Propulsion system of boat

Abstract

A propulsion system of a boat includes: at least one propulsion device provided on a hull and including a drive source and a propulsor that generates thrust with dynamic power transmitted from the drive source; and a controller configured to control the thrust of the propulsion device. The controller is capable of conducting intermittent control of intermittently changing the thrust of the at least one propulsion device, based on a condition for changing the boat speed, and turning control of causing the propulsion device to generate the thrust, based on a steering instruction angle that has been input into a steering angle inputter, when the steering angle inputter is operated during the intermittent control.

Description

BACKGROUND OF THE INVENTIONField of the Invention

[0001] The present disclosure relates to a propulsion system of a boat.Description of Related Art

[0002] In recent years, efforts to provide access to sustainable transportation systems in consideration of vulnerable people among traffic participants are becoming active. In order to develop a sustainable transportation system, research and development for further improving traffic safety and convenience through, for example, driving support for boats are in progress. As one type of driving assistance of a boat, a constitution in which a shift position of an outboard motor is automatically switched to cruise the boat at a very slow speed (so-called auto-shift control) is known. For example, Patent Document 1 (Japanese Patent No. 6156926) discloses a constitution in which the shift position is switched between a forward position and a neutral position or between a reverse position and the neutral position every predetermined time.SUMMARY OF THE INVENTION

[0003] In the related art, however, there is still room for improvement in response performance at the time of making a turn, when changing the course of the boat during the auto-shift control.

[0004] The present disclosure provides a propulsion system of a boat capable of improving response performance at the time of making a turn. The present disclosure contributes to development of a sustainable transportation system, accordingly.

[0005] In order to solve the above-described problems, the present disclosure adopts the following aspects.

[0006] (1) A propulsion system of a boat, according to one aspect of the present disclosure, includes: at least one propulsion device provided on a hull, the at least one propulsion device including a drive source and a propulsor that generates thrust with dynamic power transmitted from the drive source; and a controller including at least a processor and a memory, the controller being configured to control the thrust of the propulsion device, in which the controller is capable of conducting intermittent control of intermittently changing the thrust of the at least one propulsion device, based on a condition for changing a boat speed, and turning control of causing the propulsion device to generate the thrust toward a course of the hull, based on an instruction value to be input into a steering angle inputter, when the steering angle inputter is operated during the intermittent control.

[0007] (2) In the propulsion system of the boat according to the above (1), during the intermittent control, the controller preferably switches to the turning control from the intermittent control, in a case where a steering instruction angle to the propulsion device based on the instruction value is equal to or larger than a steering angle threshold.

[0008] (3) In the propulsion system of the boat according to the above (1) or (2), during the intermittent control, the controller preferably continues the intermittent control, in a case where a steering instruction angle to the propulsion device based on the instruction value is smaller than the steering angle threshold.

[0009] (4) In the propulsion system of the boat according to the above (2) or (3), during the intermittent control, the controller preferably switches to the turning control from the intermittent control, in a case where a state in which the steering instruction angle is equal to or larger than the steering angle threshold continues for a time equal to or longer than a first predetermined time.

[0010] (5) In the propulsion system of the boat according to one of the above (2) to (4), during the turning control, the controller preferably switches to the intermittent control from the turning control, in a case where a state in which the steering instruction angle is smaller than the steering angle threshold continues for a time equal to or longer than a second predetermined time.

[0011] (6) In the propulsion system of the boat according to the above (4), during the intermittent control, the controller preferably switches to the turning control from the intermittent control, in a case where a state in which the steering instruction angle is equal to or larger than the steering angle threshold continues for a time equal to or longer than a first predetermined time, during the turning control, the controller preferably switches to the intermittent control from the turning control, in a case where a state in which the steering instruction angle is smaller than the steering angle threshold continues for a time equal to or longer than a second predetermined time, and the second predetermined time is set to be longer than the first predetermined time.

[0012] (7) In the propulsion system of the boat according to one of the above (2) to (6), the steering angle threshold preferably includes: a right steering angle threshold for changing the course of the hull to a right side with respect to a straight advancing direction; and a left steering angle threshold for changing the course of the hull to a left side with respect to the straight advancing direction.

[0013] (8) In the propulsion system of the boat according to the above (7), absolute values of the right steering angle threshold and the left steering angle threshold are preferably set to be equal to each other.

[0014] (9) In the propulsion system of the boat according to one of the above (1) to (8), the controller preferably controls a shift position of the propulsion device, based on a requested shift position that has been input into a thrust inputter, and also controls the dynamic power of the drive source, based on requested thrust that has been input into the thrust inputter, the controller is preferably capable of conducting: a normal operation mode of controlling the dynamic power of the drive source, based on the requested thrust, in a case where the requested shift position is a forward position and the dynamic power of the drive source based on the requested thrust is other than being larger than a minimum output value; and an intermittent operation mode of conducting at least the intermittent control, in a case where the requested shift position is the forward position and the dynamic power of the drive source based on the requested thrust is a minimum output value of the drive source, and the intermittent control preferably changes the shift position between the forward position and a neutral position in a state in which the dynamic power of the drive source is kept constant.

[0015] (10) In the propulsion system of the boat according to the above (9), the controller preferably sets the shift position to the forward position at a start timing of the intermittent control.

[0016] (11) In the propulsion system of the boat according to the above (9) or (10), the condition for changing the boat speed is preferably the boat speed, and during the intermittent control, the controller preferably sets the shift position to the neutral position from the forward position, in a case where the boat speed is equal to or higher than a first speed threshold.

[0017] (12) In the propulsion system of the boat according to the above (11), during the intermittent control, the controller preferably sets the shift position to the forward position from the neutral position, in a case where the boat speed is equal to or lower than a second speed threshold, the second speed threshold being smaller than the first speed threshold.

[0018] (13) In the propulsion system of the boat according to one of the above (9) to (12), the condition for changing the boat speed is preferably at least one type of shift switching cycle that has been set in combination of a forward setting time while the forward position continues and a neutral setting time while the neutral position continues, and during the intermittent control, the controller preferably switches the shift position between the forward position and the neutral position, based on the shift switching cycle.

[0019] (14) In the propulsion system of the boat according to the above (13), during the intermittent control, the controller preferably switches to the turning control from the intermittent control, in a case where a steering instruction angle to the propulsion device based on the instruction value is equal to or larger than a steering angle threshold, during the intermittent control, the controller preferably switches to the intermittent control from the turning control, in a case where the steering instruction angle is smaller than the steering angle threshold, and when changing to the intermittent control from the turning control, the controller preferably restarts the intermittent control from a stopped timing due to changing to the turning control in the shift switching cycle of a previous time of the intermittent control.

[0020] (15) In the propulsion system of the boat according to the above (13) or (14), during the intermittent control, the controller preferably switches to the turning control from the intermittent control, in a case where a steering instruction angle to the propulsion device based on the instruction value is equal to or larger than a steering angle threshold, during the intermittent control, the controller preferably switches to the intermittent control from the turning control, in a case where the steering instruction angle is smaller than the steering angle threshold, the controller preferably sets the shift position of a start timing of the shift switching cycle to the neutral position, and when changing to the intermittent control from the turning control, the controller preferably conducts the intermittent control from the start timing of the shift switching cycle.

[0021] (16) In the propulsion system of the boat according to one of the above (13) to (15), a plurality of types of the shift switching cycles in which at least one of the neutral setting time and the forward setting time is different are preferably provided, and the controller preferably conducts the intermittent control, based on one of the plurality of types of the shift switching cycles.

[0022] (17) In the propulsion system of the boat according to one of the above (9) to (16), the at least one propulsion device preferably includes: a left propulsion device provided on a left side with respect to a center in a left-right direction of the hull; and a right propulsion device provided on a right side with respect to the center in the left-right direction, and the controller preferably makes switching timings of the shift positions of the left propulsion device and the right propulsion device different from each other in the intermittent control.

[0023] (18) In the propulsion system of the boat according to one of the above (9) to (16), the at least one propulsion device preferably includes: a left propulsion device provided on a left side with respect to a center in a left-right direction of the hull; and a right propulsion device provided on a right side with respect to the center in the left-right direction, during the intermittent control, the controller preferably switches to the turning control from the intermittent control, in a case where a steering instruction angle based on the instruction value is equal to or larger than a steering angle threshold, the steering angle threshold preferably includes: a right steering angle threshold for changing the course of the hull to the right side with respect to a straight advancing direction; and a left steering angle threshold for changing the course of the hull to the left side with respect to the straight advancing direction, an absolute value of the right steering angle threshold of the left propulsion device is preferably set to be smaller than an absolute value of the right steering angle threshold of the right propulsion device, and an absolute value of the left steering angle threshold of the right propulsion device is preferably set to be smaller than an absolute value of the left steering angle threshold of the left propulsion device.

[0024] (19) In the propulsion system of the boat according to one of the above (1) to (16), the at least one propulsion device preferably includes: outer propulsion devices provided at both end portions of the hull in a left-right direction; and at least one inner propulsion device provided between the outer propulsion devices, and the controller preferably causes any of the outer propulsion devices and the inner propulsion device to conduct the intermittent control.

[0025] (20) In the propulsion system of the boat according to the above (19), the controller preferably sets a shift position of the inner propulsion device to a neutral position, when conducting the intermittent control on the outer propulsion devices.

[0026] (21) In the propulsion system of the boat according to the above (20), the controller preferably sets a shift position of the outer propulsion devices to a forward position, when conducting the intermittent control on the inner propulsion device.

[0027] (22) In the propulsion system of the boat according to one of the above (1) to (21), the instruction value is preferably an operation amount on the steering angle inputter.

[0028] (23) In the propulsion system of the boat according to one of the above (1) to (21), the instruction value is preferably an operation amount on the steering angle inputter per unit time.

[0029] According to the above aspects, response performance at the time of making a turn can be improved.BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG. 1 is a plan view of a boat according to a first embodiment;

[0031] FIG. 2 is a side view illustrating a propulsion device;

[0032] FIG. 3 is a block diagram of the boat;

[0033] FIG. 4 is a state transition diagram illustrating switching to and from an intermittent operation mode;

[0034] FIG. 5 is a timing chart showing the operation of a propulsion system according to the first embodiment;

[0035] FIG. 6 is a flowchart showing intermittent control (auto-shift control) during an intermittent operation mode in the propulsion system according to the first embodiment;

[0036] FIG. 7 is a flowchart showing a switching operation between the intermittent operation mode and a normal operation mode in the propulsion system according to the first embodiment;

[0037] FIG. 8 is a flowchart showing the operation during the intermittent operation mode;

[0038] FIG. 9 is a diagram illustrating a relationship between a steering angle threshold and a shift position;

[0039] FIG. 10 is a plan view of the boat at the time of turning control (turning to the right) according to the first embodiment;

[0040] FIG. 11 is a timing chart showing the operation of the propulsion system according to a second embodiment;

[0041] FIG. 12 is a flowchart showing a shift switching operation during an intermittent operation mode in the propulsion system according to the second embodiment;

[0042] FIG. 13 is a flowchart showing the operation during the intermittent operation mode in the propulsion system according to the second embodiment;

[0043] FIG. 14 is a timing chart showing the operation of the propulsion system according to a third embodiment;

[0044] FIG. 15 is a flowchart showing a switching operation between the intermittent operation mode and the normal operation mode and a turning operation during the intermittent operation mode in the propulsion system according to the third embodiment;

[0045] FIG. 16 is a flowchart showing an operation method of the propulsion system according to a fourth embodiment;

[0046] FIG. 17 is a plan view of a boat according to a fifth embodiment;

[0047] FIG. 18 is a plan view showing the operation of the boat according to the fifth embodiment at the time of turning to the right;

[0048] FIG. 19 is a plan view showing the operation of the boat according to the fifth embodiment at the time of turning to the left; and

[0049] FIG. 20 is a plan view of a boat according to a sixth embodiment.DETAILED DESCRIPTION OF THE INVENTION

[0050] Hereinafter, embodiments in the present disclosure will be described with reference to the drawings. In embodiments and modifications to be described below, corresponding constitutions are denoted by the same reference numbers, and descriptions will be omitted, in some cases. In the following description, for example, expressions indicating relative or absolute arrangements such as “parallel”, “orthogonal”, “center”, and “coaxial” represent not only strictly such arrangements but also a state of being relatively displaced with a tolerance or with an angle or a distance with which the same function is obtainable. In addition, in the present embodiment, “face each other” is not limited to a case where the orthogonal directions (normal directions) of two surfaces coincide with each other, and includes a case where the orthogonal directions intersect each other.

[0051] It is assumed that front, rear, upper, lower, left, and right directions in the following description respectively coincide with the directions of a boat 1. In this case, an arrow FR in the drawing indicates a forward side of the boat 1, an arrow UP in the drawing indicates an upper side of the boat 1, and an arrow LH in the drawing indicates a leftward side of the boat 1. In addition, a center line CL indicates the center position of the boat 1 in a left-right direction (a width direction).First Embodiment[Boat 1]

[0052] FIG. 1 is a plan view of a boat 1 according to a first embodiment.

[0053] The boat 1 illustrated in FIG. 1 includes a hull 2, a plurality of propulsion devices 3, a steering angle inputter 4, a thrust inputter 5, a boat speed sensor 6 (see FIG. 3), an operation unit 7, and a controller 8. Noe that the plurality of propulsion devices 3 and the controller 8 constitute a propulsion system according to the present embodiment.<Propulsion Device 3>

[0054] The propulsion device 3 includes: a right propulsion device 3a, which is provided on the right side of the stern with respect to the center line CL; and a left propulsion device 3b, which is provided on the left side of the stern with respect to the center line CL. That is, the boat 1 in the present embodiment is a so-called small-sized vessel in which the two propulsion devices 3 (the right propulsion device 3a and the left propulsion device 3b) are provided at both left and right end portions of the stern with the center line CL interposed between them. Hereinafter, in a case where it is not necessary to distinguish between the propulsion devices 3a and 3b, they will be collectively described as the propulsion device 3.

[0055] FIG. 2 is a side view of the propulsion device 3. FIG. 3 is a block diagram of the boat 1.

[0056] As illustrated in FIGS. 2 and 3, the propulsion device 3 is, for example, an outboard motor. The propulsion device 3 includes: a casing 11; a drive source 12; a drive shaft 13; a propulsor 14; and a shift switching mechanism 15.

[0057] The casing 11 is attached to a bracket 9, which is provided at the stern, via a steering shaft (swivel shaft) 16, which extends in an up-down direction. The propulsion device 3 is attached to the hull 2 so as to be rotatable around a steering shaft 16 in accordance with the operation on a steering actuator 17 (see FIG. 3).

[0058] The drive source 12 is, for example, an internal combustion engine such as an engine. The drive source 12 is accommodated in an upper portion of the casing 11 with a crankshaft extending in the up-down direction. Dynamic power (engine speed) of the drive source 12 is set, based on an opening degree of a throttle valve. The throttle valve is driven by the operation of a throttle actuator 18 (see FIG. 3).

[0059] The drive shaft 13 transmits the dynamic power generated by the drive source 12 to the propulsor 14 via the shift switching mechanism 15. The drive shaft 13 extends in the up-down direction in the casing 11. An upper end portion of the drive shaft 13 is connected with the drive source 12.

[0060] The propulsor 14 includes a propeller shaft 21 and propellers 22.

[0061] The propeller shaft 21 is provided at a lower end portion of the casing 11 so as to be rotatable around an axis along a front-rear direction. A front end portion of the propeller shaft 21 is connected with the shift switching mechanism 15 in the casing 11.

[0062] The propellers 22 are provided projecting on the outside of the casing 11 at a rear end portion of the propeller shaft 21. The propellers 22 rotate integrally with the propeller shaft 21.

[0063] The shift switching mechanism 15 includes a drive gear 25, a forward gear 26, a reverse gear 27, and a clutch 28.

[0064] The drive gear 25 is provided at a lower end portion of the drive shaft 13. The drive gear 25 is rotatable integrally with the drive shaft 13.

[0065] The forward gear 26 and the reverse gear 27 are rotatably provided at positions that face each other in the front-rear direction interposing the drive gear 25 on the propeller shaft 21. The forward gear 26 and the reverse gear 27 mesh with the drive gear 25. The forward gear 26 and the reverse gear 27 rotate in opposite directions in accordance with the rotation of the drive gear 25.

[0066] The clutch 28 switches a connection state or a disconnection state of the dynamic power between either the forward gear 26 or the reverse gear 27 and the propeller shaft 21. The clutch 28 is provided in a part, positioned between the forward gear 26 and the reverse gear 27, of the propeller shaft 21 so as to be rotatable integrally with the propeller shaft 21. The clutch 28 is provided to be movable in the front-rear direction along the propeller shaft 21 in accordance with the operation of a shift actuator 29. The clutch 28 meshes with the forward gear 26, and is capable of transmitting the rotational force of the forward gear 26 to the propeller shaft 21 (a forward position F). This causes the propellers 22 to rotate in the normal rotation direction, thereby applying thrust in a forward advancing direction to the boat 1. The clutch 28 meshes with the reverse gear 27, and is capable of transmitting the rotational force of the reverse gear 27 to the propeller shaft 21 (a reverse position R). This causes the propellers 22 to rotate in the reverse rotation direction, thereby applying thrust in a rearward advancing direction to the boat 1. On the other hand, in a state in which the clutch 28 does not mesh with either the forward gear 26 or the reverse gear 27, the rotational force is not transmitted to the propeller shaft 21 (a neutral position N).<Steering Angle Inputter 4>

[0067] As illustrated in FIGS. 1 and 3, the steering angle inputter 4 is provided in a cockpit of the hull 2. The steering angle inputter 4 is, for example, a steering wheel provided rotatably to the left and right. The steering angle inputter 4 receives an operation of a user when changing the course of the boat 1 (hull 2). That is, the steering angle inputter 4 receives an operation for changing the direction (a steering angle θ) of the propulsion device 3 around the steering shaft 16. The steering angle θ denotes an inclination angle of the propulsion device 3 with respect to a center line CL in a plan view. In the present embodiment, the steering angle θ of the propulsion device 3, in a state in which the propeller shaft 21 is parallel to the center line CL in a plan view, is set as a reference value (0 degrees). An operation amount in accordance with the rotation operation on the steering angle inputter 4 is detected by a steering angle sensor 31. The steering angle sensor 31 outputs a detection signal based on an operation amount on the steering angle inputter 4 to the controller 8, as an instruction value. Note that as the steering angle inputter 4, in addition to the steering wheel, a joystick may be used, and the steering angle inputter 4 may be mounted as a switch or the like of the operation unit 7.<Thrust Inputter 5>

[0068] The thrust inputter 5 is provided in the cockpit of the hull 2. The thrust inputter 5 is, for example, a throttle lever (accelerator lever). The thrust inputter 5 receives the operation of a user when changing the thrust of the propulsion device 3 (requested thrust Sd) or the shift position of the propulsion device 3 (requested shift position). The thrust inputter 5 is capable of reciprocating in an operation area in which three shift areas of the forward position F, the neutral position N, and the reverse position R are aligned in accordance with rotation, sliding, or the like. Note that in the present embodiment, the propulsion device 3 will be described using an outboard motor as an example, but the present disclosure is not limited to this constitution. In addition to the outboard motor, the propulsion device may be an inboard motor, an inboard and outboard motor, a water jet machine, or the like. For example, in a case of the inboard motor, the direction of the thrust of the propulsion device 3 may be changed by changing the direction of a separately provided rudder. For example, in a case of the water jet machine, the direction of the thrust of the propulsion device 3 may be changed by changing the direction of a water flow. Further, the outboard motor and a side thruster may be combined together to constitute the propulsion device 3. In this case, the direction of the thrust of the propulsion device 3 may be changed by the ratio between the thrust of the outboard motor and the thrust of the side thruster.

[0069] In the boat 1, it is possible to set the requested shift position in accordance with the position of the thrust inputter 5 in the operation area. That is, in a case where the thrust inputter 5 is located in the shift area of the forward position F, it is possible to request the controller 8 to set the shift position to the forward position F. In a case where the thrust inputter 5 is located in the shift area of the neutral position N, it is possible to request the controller 8 to set the shift position to the neutral position N. In a case where the thrust inputter 5 is located in the shift area of the reverse position R, it is possible to request the controller 8 to set the shift position to the reverse position R.

[0070] In the boat 1, it is possible to set the requested thrust in accordance with the position of the thrust inputter 5 in the operation area. That is, in a case where the thrust inputter 5 is located in the shift area of the neutral position N, it is possible to request the controller 8 to set the thrust to zero. In a case where the thrust inputter 5 is set in the shift area of the forward position F or the reverse position R, it is possible to request the controller 8 to increase the thrust in the corresponding advancing direction, as the thrust inputter 5 is apart from the shift area of the neutral position N. The position (a lever opening rate LE) of the thrust inputter 5 is detected by a position sensor 32. The position sensor 32 outputs, to the controller 8, a detection signal based on the position (the lever opening rate LE) of the thrust inputter 5.<Boat Speed Sensor 6>

[0071] As illustrated in FIG. 3, the boat speed sensor 6 detects a speed (boat speed) V of the boat 1. The boat speed sensor 6 receives a positioning signal from a positioning satellite such as a global positioning system (GPS), for example, measures an absolute position (latitude, longitude) of the boat 1, based on the received positioning signal, and calculates the boat speed (the boat speed relative to the ground) V, based on time-series positioning results. The boat speed sensor 6 may be an acoustic sensor or an electromagnetic sensor that detects the boat speed (the boat speed relative to the water) V of the boat 1. The boat speed sensor 6 may estimate the boat speed V, based on the engine speed. Note that a plurality of the speed sensors 6 may be used in combination.<Operation Unit 7>

[0072] The operation unit 7 receives various operations in the boat 1. The operation unit 7 is constituted to be manually operable by a user, such as a multi-function display (MFD). Note that the operation unit 7 may be an external device such as a mobile terminal connected to the boat 1 in a wired or wireless manner.

[0073] FIG. 4 is a state transition diagram illustrating switching between a normal operation mode and an intermittent operation mode.

[0074] As illustrated in FIG. 4, in the boat 1 in the present embodiment, an intermittent operation mode (an auto-shift mode) and a normal operation mode (a normal navigation mode) are switched in accordance with the operation on the thrust inputter 5, for example.

[0075] The intermittent operation mode is a mode of cruising the boat 1 in a very slow speed region within a predetermined speed range (for example, the speed may be approximately 2 km / h to approximately 4 km / h or may be slower than it). The intermittent operation mode is applied when the thrust (the requested thrust Sd) generated by the propulsion device 3 is, for example, equal to or smaller than the thrust to be output at the minimum output value (rotation speed at the time of idling) of the drive source 12. In the intermittent operation mode, for example, when the boat 1 moves forward (the requested shift position is the forward position F), the shift position is automatically switched between the forward position F and the neutral position N. Accordingly, in the intermittent operation mode, it becomes possible to cruise the boat 1 at the boat speed V, which is achievable with equal to or smaller than the thrust to be output at the minimum output value of the drive source 12.

[0076] The normal operation mode is a mode of cruising the boat 1 in a speed region (a normal speed region) other than the very slow speed region. The normal operation mode is applied when the thrust (the requested thrust Sd) generated by the propulsion device 3 is larger than the thrust to be output at the minimum output value of the drive source 12, for example. In the normal operation mode, for example, when the boat 1 moves forward, output (a throttle opening degree φ) of the drive source 12 is adjusted in accordance with the position (the lever opening rate LE) of the thrust inputter 5, and thus the thrust generated by the propulsion device 3 is adjusted. Note that in the present embodiment, it is possible to select whether the switching control between the intermittent operation mode and the normal operation mode is set to a valid state or an invalid state, by using, for example, the operation (ON / OFF operation) on the operation unit 7.<Controller 8>

[0077] The controller 8 integrally controls the operation of the boat 1 (the propulsion device 3). The controller 8 is an integrated or a plurality of electronic control devices included in the boat 1. The controller 8 is implemented by, for example, a hardware processor such as a central processing unit (CPU) executing a program (software) stored in a read only memory (ROM), a random access memory (RAM), or the like. Some or all of these constituent elements may be implemented by a hardware (a circuit part; including circuitry) such as a large scale integration (LSI), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a graphics processing unit (GPU), or system on chip (SOC) or may be implemented by software and hardware in cooperation.

[0078] The controller 8 includes a storage 60, an acquisitor 61, a determiner 62, and a drive processor 63.

[0079] The storage 60 includes, for example, a ROM or the like. In the storage 60, for example, programs, various data, and the like necessary for cruising the boat 1, such as the intermittent operation mode and the normal operation mode, are stored.

[0080] The acquisitor 61 includes, for example, a RAM or the like. The acquisitor 61 acquires detection results of various sensors.

[0081] The determiner 62 includes, for example, a CPU or the like. The determiner 62 determines the state of the boat 1, based on information obtained by the acquisitor 61 and information stored in the storage 60.

[0082] The drive processor 63 includes, for example, a CPU or the like. The drive processor 63 controls the operation of various actuators, based on a determination result in the determiner 62 and the information stored in the storage 60 or the acquisitor 61, and also controls the operation of the engine such as fuel injection or ignition by a known ECU provided in the propulsion device 3.[Operation Method of Propulsion System]

[0083] Next, an operation method of the propulsion system will be described. Hereinafter, the switching operation between the intermittent operation mode and the normal operation mode, and a turning operation during the intermittent operation mode when the boat 1 moves forward (the requested shift position is the forward movement position F) will be mainly described. Processing to be described below is repeatedly performed, for example, at a predetermined control cycle (for example, several tens of [msec]).

[0084] FIG. 5 is a timing chart showing the operation of the propulsion system. FIG. 6 is a flowchart showing intermittent control (the auto-shift control) during the intermittent operation mode in the propulsion system.

[0085] As illustrated in FIGS. 5 and 6, in step S11, the controller 8 determines whether the current shift position is the forward position F, based on a detection result of the position sensor 32 (for example, time t1 in FIG. 5).

[0086] In a case where the determination result of step S11 is “YES”, it is determined that the current shift position is the forward position F, and processing proceeds to step S12.

[0087] In step S12, the controller 8 determines whether the boat speed V is equal to or higher than a first speed threshold V1, based on a detection result of the boat speed sensor 6. The first speed threshold V1 is, for example, an upper limit value of the very slow speed region (a boundary value between the very slow speed region and a normal speed region). In this case, the first speed threshold V1 is preferably smaller than the boat speed V, which is achievable with the minimum output value of the drive source 12 (the minimum value of the throttle opening degree φ). However, the first speed threshold V1 may be appropriately set by utilizing actual travel data.

[0088] In a case where the determination result of step S12 is “YES” (V≥V1), the processing proceeds to step S13. That is, in the case where the determination result of step S12 is “YES”, it is determined that the thrust deviates from the very slow speed region against the requested thrust Sd or there is a possibility of deviating from the very slow speed region (for example, time t2 in FIG. 5).

[0089] In step S13, the controller 8 changes the shift position of the propulsion device 3 to the neutral position N. Accordingly, the thrust of the propulsion device 3 becomes zero. That is, an increase in the boat speed V caused by the thrust of the propulsion device 3 is suppressed (for example, time t2 to time t3 in FIG. 5).

[0090] In a case where the determination result of step S12 is “NO” (V<V1), the processing proceeds to step S14. That is, in the case where the determination result in step S12 is “NO”, it is determined that the boat is cruising in the very slow speed region, based on the requested thrust Sd.

[0091] In step S14, the controller 8 continues the shift position of the propulsion device 3 at the forward position F. Accordingly, the thrust of the propulsion device 3 is continuously applied, and the boat speed V increases due to the thrust of the propulsion device 3.

[0092] In a case where the determination result in step S11 is “NO”, it is determined that the current shift position is the neutral position N, and the processing proceeds to step S15.

[0093] In step S15, it is determined whether the boat speed V is equal to or lower than a second speed threshold V2. The second speed threshold V2 is a lower limit value of the very slow speed region.

[0094] In a case where the determination result of step S15 is “YES” (V≤V2), the processing proceeds to step S16. That is, in the case where the determination result in step S15 is “YES”, the controller 8 determines that the vehicle deviates from the very slow speed region against the requested thrust or there is a possibility of deviating from the very slow speed region (for example, time t3 in FIG. 5).

[0095] In step S16, the controller 8 changes the shift position of the propulsion device 3 to the forward position F. Accordingly, the thrust of the propulsion device 3 is applied, and thus the boat speed V increases (for example, time t3 to time t4 in FIG. 5).

[0096] In a case where the determination result of step S15 is “NO” (V>V2), the processing proceeds to step S17. That is, in the case where the determination result in step S16 is “NO”, the controller 8 determines that the vehicle is cruising in the very slow speed region, based on the requested thrust Sd.

[0097] In step S17, the controller 8 maintains the shift position of the propulsion device 3 at the neutral position N. Accordingly, an increase in the boat speed V caused by the thrust of the propulsion device 3 is suppressed.

[0098] In the intermittent operation mode, by repeating the routine of the above-described intermittent control, it becomes possible to cruise the boat 1 while maintaining the boat speed V within the very slow speed region.

[0099] FIG. 7 is a flowchart showing a switching operation between the intermittent operation mode and the normal operation mode in the propulsion system.

[0100] As illustrated in FIG. 7, in step S21, the controller 8 determines whether the shift position is the forward position F and the requested thrust Sd is equal to or smaller than the thrust to be output at the minimum output value of the drive source 12.

[0101] In a case where a determination result of step S21 is “NO”, the processing proceeds to step S22. That is, in the case where the determination result in step S21 is “NO”, the controller 8 determines that the shift position is other than the forward position F or the requested thrust Sd is larger than the thrust to be output at the minimum output value of the drive source 12.

[0102] In step S22, the controller 8 performs the normal operation mode. In the normal operation mode, the output (the throttle opening degree φ) of the drive source 12 is adjusted in accordance with the position (the lever opening rate LE) of the thrust inputter 5, and thus the thrust generated by the propulsion device 3 is adjusted. Accordingly, the boat 1 cruises at the boat speed V corresponding to the requested thrust by the user.

[0103] In a case where a determination result of step S21 is “YES”, the processing proceeds to step S23. That is, in the case where the determination result of step S21 is “YES”, the controller 8 determines that the shift position is the forward position F and the requested thrust Sd is equal to or smaller than the thrust to be output at the minimum output value of the drive source 12.

[0104] FIG. 8 is a flowchart showing the operation during the intermittent operation mode.

[0105] As illustrated in FIGS. 5 and 8, in step S25, the controller 8 determines whether a steering instruction angle θd is equal to or larger than a steering angle threshold θa. The steering instruction angle θd is calculated from a map or the like stored beforehand in the storage 60, based on, for example, an operation amount on the steering angle inputter 4, and is the steering angle θ of the propulsion device 3 necessary for the boat 1 to make a turn in response to a steering request of the user. The controller 8 rotates the propulsion device 3 around the steering shaft 16, based on the steering instruction angle θd that has been calculated.

[0106] FIG. 9 is a diagram illustrating a relationship between the steering angle threshold θa and a shift position.

[0107] As illustrated in FIG. 9, the steering angle threshold θa includes a right steering angle threshold θar, which is a threshold for a direction of causing the boat 1 to turn to the right with respect to a straight advancing direction, and a left steering angle threshold θal, which is a threshold for a direction of causing the boat 1 to turn to the left with respect to the straight advancing direction. In the present embodiment, the absolute values of the right steering angle threshold θar and the left steering angle threshold θal are set to be equal to each other.

[0108] In a case where a determination result of step S25 is “YES”, the processing proceeds to step S26 (θ≥θa). That is, in the case where the determination result in step S25 is “YES”, the controller 8 determines that the turning angle of the boat 1 is large (for example, time t5 in FIG. 5).

[0109] In step S26, the controller 8 sets “1” to the steering flag, and the processing proceeds to step S27. Note that in a case where the steering instruction angle θd is smaller than the steering angle threshold θa, the steering flag is “0”, and in a case where the steering angle θ is equal to or larger than the steering angle threshold θa, the steering flag is “1”.

[0110] In step S27, the controller 8 determines whether a state in which the steering flag is “1” is continuing for equal to or longer than a first predetermined time T1. The first predetermined time T1 is set to be equal to a control cycle, for example.

[0111] In a case where the determination result of step S27 is “NO”, the processing proceeds to step S28, and the intermittent control illustrated in FIG. 6 continues.

[0112] In a case where the determination result of step S27 is “YES”, the processing proceeds to step S29.

[0113] FIG. 10 is a plan view of the boat 1 at the time of turning control (turning to the right).

[0114] As illustrated in FIGS. 5, 8, and 10, in step S29, the controller 8 sets the shift position to the forward position F (for example, time t6 in FIG. 5). That is, during the intermittent operation mode, upon determination that the turning angle of the boat 1 is large, the controller 8 sets the shift position to the forward position F regardless of the boat speed V (the turning control). Accordingly, the boat 1 cruises while increasing the boat speed V toward a desired course.

[0115] As illustrated in FIGS. 5 and 8, in a case where the determination result of step S25 is “NO”, the processing proceeds to step S30 (θ<θa). That is, in the case where the determination result in step S25 is “NO”, the controller 8 determines that the course of the boat 1 remains straight or the turning angle is small.

[0116] In step S30, the controller 8 sets “0” to the steering flag, and the processing proceeds to step S31. Note that in a case where the steering flag is “0”, a shift switching operation (the intermittent control) is performed, based on the boat speed V as described above in the intermittent operation mode.

[0117] In step S31, the controller 8 determines whether a state in which the steering angle flag is “0” is continuing for equal to or longer than a second predetermined time T2 (for example, between times t7 and t8 in FIG. 5). The second predetermined time T2 is set to be longer than the first predetermined time T1 (for example, 1 sec).

[0118] In a case where a determination result of step S31 is “NO”, the processing proceeds to step S32.

[0119] In step S32, the controller 8 continues the shift position of the propulsion device 3 at the forward position F. Note that in step S32, for example, during the turning control, in a case where the steering angle θ has just returned to be smaller than the steering angle threshold θa, the shift position at the forward position F continues (the turning control continues).

[0120] In a case where the determination result of step S31 is “YES”, the processing proceeds to step S33.

[0121] In step S33, the controller 8 conducts the intermittent control illustrated in FIG. 6. Note that at time t8, since the current shift position is the forward position F and the boat speed V is smaller than the first speed threshold V1, the shift position at the forward position F continues, even though the control returns to the intermittent control.

[0122] Then, at time t9, by setting the requested shift position to the neutral position N (the requested thrust Sd is zero), the shift position of each propulsion device 3 becomes the neutral position N.

[0123] As illustrated in FIG. 4, during the intermittent operation mode, in a case where the shift position is the forward position F, when both of the following cases (1-1) and (1-2) are satisfied, the shift position is switched to the neutral position N from the forward position F.

[0124] (1-1) A case where the boat speed V is equal to or higher than the first speed threshold V1 during the intermittent control.

[0125] (1-2) A case where during the turning control, after the steering instruction angle θd returns to be smaller than the steering angle threshold θa, a state of being smaller than the steering angle threshold θa is continuing for the second predetermined time T2 (switching to the intermittent control from the turning control).

[0126] During the intermittent operation mode, when the shift position is the neutral position N, the shift position is switched to the forward position F from the neutral position N in any one of the following cases (2-1) and (2-2).

[0127] (2-1) A case where the boat speed is equal to or lower than the second speed threshold V2 during the intermittent control.

[0128] (2-2) A case where the steering instruction angle θd is equal to or larger than the steering angle threshold θa during the intermittent control (switching to the turning control from the intermittent control).

[0129] In this manner, the propulsion system in the present embodiment includes: the drive source 12; the propulsor 14, which generates thrust in accordance with the dynamic power transmitted from the drive source 12; at least one propulsion device 3, which is provided on the hull 2; and the controller 8, which controls the thrust of the propulsion device 3. The controller 8 is capable of conducting the intermittent control of intermittently changing the thrust of at least one propulsion device 3, based on a condition for changing the boat speed V, and the turning control of generating the thrust in the propulsion device 3 toward the course of the hull 2 based on the instruction value to be input into the steering angle inputter 4, when the steering angle inputter 4 is operated during the intermittent control.

[0130] According to this constitution, by switching to the turning control from the intermittent control during the intermittent operation mode, the thrust of the propulsion device 3 is controlled toward the course of the hull 2, based on the instruction value to be input into the steering angle inputter 4 regardless of the condition for changing the boat speed V. Accordingly, cruising to make a turn in accordance with the instruction of the user is smoothly achievable, so that the response performance at the time of making a turn can be improved. As a result, in the present embodiment, it becomes possible to contribute to development of a sustainable transportation system.

[0131] In the propulsion system in the present embodiment, the controller 8 switches to the turning control from the intermittent control, when the steering instruction angle θd is equal to or larger than the steering angle threshold θa during the intermittent control in the intermittent operation mode.

[0132] According to this constitution, it becomes possible to continue the very slow speed cruising at the time of not making a turn or when the turning angle is small.

[0133] In the propulsion system in the present embodiment, the controller 8 continues the intermittent control, when the steering instruction angle θd is smaller than the steering angle threshold θa during the intermittent control in the intermittent operation mode.

[0134] According to this constitution, it becomes possible to continue the very slow speed cruising at the time of not making a turn or when the turning angle is small.

[0135] In the propulsion system in the present embodiment, during the intermittent control in the intermittent operation mode, the controller 8 switches to the turning control from the intermittent control, when the state in which the steering instruction angle θd is equal to or larger than the steering angle threshold θa is continuing for equal to or longer than the first predetermined time T1.

[0136] According to this constitution, an occurrence of the hunting between the intermittent control and the turning control can be suppressed, so that a sense of discomfort given to the user can be suppressed.

[0137] In the propulsion system in the present embodiment, during the turning control in the intermittent operation mode, the controller 8 switches to the intermittent control from the turning control, when the steering instruction angle θd is smaller than the steering angle threshold θa and the state in which the steering instruction angle θd is smaller than the steering angle threshold θa is continuing for equal to or longer than the second predetermined time T2.

[0138] According to this constitution, an occurrence of the hunting between the intermittent control and the turning control can be suppressed, so that a sense of discomfort given to the user can be suppressed.

[0139] In the propulsion system in the present embodiment, the second predetermined time T2 is set to be longer than the first predetermined time T1.

[0140] According to this constitution, by ensuring the second predetermined time T2 to be long, the delay of the turning performance can be compensated in the latter half of the turning, and the turning amount in accordance with an intention of the user can be ensured even during the intermittent operation mode. On the other hand, by shortening the first predetermined time T1, it is possible to improve the response performance in the former half of the turning.

[0141] In the propulsion system in the present embodiment, the steering angle threshold θa includes the right steering angle threshold θar for changing the course of the hull 2 to the right with respect to the straight advancing direction, and the left steering angle threshold θal for changing the course of the hull 2 to the left with respect to the straight advancing direction.

[0142] According to this constitution, it becomes possible to determine whether to continue the intermittent control or to conduct the turning control at each time of turning to the right and turning to the left during the intermittent operation mode.

[0143] In the propulsion system in the present embodiment, the absolute values of the right steering angle threshold θar and the left steering angle threshold θal are set to be equal to each other.

[0144] According to this constitution, since it becomes possible to unify the operation feeling at the time of turning to the right and at the time of turning to the left, so that a sense of discomfort given to the user can be suppressed.

[0145] In the propulsion system in the present embodiment, the controller 8 is capable of performing the normal operation mode of controlling the dynamic power of the drive source 12, based on the requested thrust Sd, in a case where the requested shift position is the forward position F and the output of the drive source 12 based on the requested thrust Sd is larger than the minimum output value, and the intermittent operation mode of conducting at least the intermittent control in a case where the requested shift position is the forward position F and the output of the drive source 12 based on the requested thrust Sd is the minimum output value of the drive source 12. In the intermittent control, the shift position is changed between the forward position F and the neutral position N, while the output of the drive source 12 is kept constant.

[0146] According to this constitution, in the intermittent control in the intermittent operation mode, for example, it becomes possible to cruise the boat 1 at the boat speed V, which is achievable with equal to or smaller thrust to be output at the minimum output value of the drive source 12, without the user manually switching the shift position. Accordingly, convenience can be improved.

[0147] In the propulsion system in the present embodiment, in the intermittent operation mode, the controller 8 sets the shift position to the neutral position N from the forward position F, when the boat speed V is equal to or higher than the first speed threshold V1.

[0148] According to this constitution, since the thrust of the propulsion device 3 becomes zero when the boat speed V is equal to or higher than the first speed threshold V1, an increase in the boat speed V caused by the thrust of the propulsion device 3 is suppressed. As a result, it becomes possible to cruise the boat 1 at a very slow speed of the boat speed V, which is equal to or lower than the first speed threshold V1.

[0149] In the propulsion system in the present embodiment, in the intermittent operation mode, the controller 8 sets the shift position to the forward position from the neutral position, when the boat speed V is equal to or lower than the second speed threshold V2.

[0150] According to this constitution, it becomes possible to increase the boat speed V by applying the thrust of the propulsion device 3. As a result, it becomes possible to cruise the boat 1 at a very slow speed of the boat speed V, which is equal to or higher than the second speed threshold V2.

[0151] Furthermore, by conducting the intermittent control using the boat speed V itself as the condition for changing the boat speed V as described in the present embodiment, it becomes possible to maintain the boat speed V within a desired very slow speed region with high accuracy, as compared with a case where the intermittent control is conducted, based on time, for example.

[0152] In the propulsion system in the present embodiment, the instruction value is an operation amount on the steering angle inputter 4.

[0153] According to this constitution, smooth turning is enabled regardless of the situation at the time of making a turn.Modifications of First Embodiment

[0154] In the above-described first embodiment, in the intermittent operation mode, when the steering instruction angle θd is equal to or larger than the steering angle threshold θa, the intermittent control is switched to the turning control. However, the present disclosure is not limited to this constitution. When the absolute value of the steering instruction angle θd is larger than 0 degrees, the intermittent control may be switched to the turning control.

[0155] In the above-described first embodiment, in the intermittent operation mode, the constitution has been described in which the intermittent control is switched to the turning control from the intermittent control, in a case where the steering instruction angle θd, which is equal to or larger than the steering angle threshold θa, is continuing for equal to or longer than the first predetermined time T1. However, the present disclosure is not limited to this constitution. When the steering instruction angle θd is equal to or larger than the steering angle threshold θa, the intermittent control may be promptly switched to the turning control.

[0156] In the above-described embodiment, the constitution has been described in which the turning control is switched to the intermittent control from the turning control, in a case where after the steering instruction angle θd returns to be smaller than the steering angle threshold θa in the intermittent operation mode and the steering instruction angle θd, which is smaller than the steering angle threshold θa, is continuing for equal to or longer than the second predetermined time T2. However, the present disclosure is not limited to this constitution. The turning control may be promptly switched to the intermittent control, when the steering instruction angle θd returns to be smaller than the steering angle threshold θa.

[0157] In the above-described embodiment, the constitution in which the second predetermined time T2 is set to be longer than the first predetermined time T1 has been described. However, the present disclosure is not limited to this constitution. The second predetermined time T2 may be equal to or shorter than the first predetermined time T1.

[0158] In the above-described embodiment, the constitution in which the right steering angle threshold θar and the left steering angle threshold θal are included as the steering angle threshold θa has been described. However, the present disclosure is not limited to this constitution.

[0159] In the above-described first embodiment, as the determination of switching between the intermittent operation mode and the normal operation mode, the constitution has been described in which the maximum value (the switching threshold Va) of the boat speed V, which is achievable when the requested thrust is equal to or smaller than the thrust to be output at the minimum output value of the drive source 12. However, the present disclosure is not limited to this constitution. The switching threshold Va can be set with any value.

[0160] In the above-described first embodiment, the constitution has been described in which the shift position is switched, based on the boat speed V, from a start timing of the intermittent operation mode (the intermittent control). However, the present disclosure is not limited to this constitution. At the start timing of the intermittent operation mode (the intermittent control), after the shift position is continuously located at the forward position F for a predetermined period of time, the shift position may be switched, based on the boat speed V.

[0161] According to this constitution, it becomes possible to suppress a decrease amount of the boat speed V at the time of changing to the intermittent operation mode from the normal operation mode. Accordingly, a sense of discomfort given to the user can be suppressed.Second Embodiment

[0162] In the first embodiment, the boat speed V itself is used as the condition for changing the boat speed V. On the other hand, a second embodiment is different from the above-described first embodiment in that a period of time (a shift switching cycle) is used as the condition for changing the boat speed V in the intermittent operation mode (the intermittent control). FIG. 11 is a timing chart showing the operation of the propulsion system.

[0163] As indicated by time t11 to time t13 in FIG. 11, the intermittent control in the present embodiment switches the shift position between the forward position F and the neutral position N, based on a shift switching cycle Ts. The shift switching cycle Ts denotes a period of time while a forward setting time Tfl and a neutral setting time Tnl are respectively performed once. In the present embodiment, during the intermittent control, the shift position is switched between the forward position F and the neutral position N by repeating the shift switching cycle Ts. Note that the shift switching cycle Ts is set to be longer than the control cycle and the first predetermined time T1.

[0164] FIG. 12 is a flowchart showing a shift switching operation during the intermittent operation mode in the propulsion system.

[0165] As illustrated in FIGS. 11 and 12, in step S51, whether the current shift position is the forward position F is determined, based on a detection result of the position sensor 32 (for example, time t11 in FIG. 11).

[0166] In a case where a determination result of step S51 is “YES”, it is determined that the current shift position is the forward position F, and processing proceeds to step S52.

[0167] In step S52, the controller 8 determines whether duration of the forward position F (forward duration Tf) is equal to or longer than the forward setting time Tfl. Note that the forward duration Tf is measured by a timer provided in the controller 8.

[0168] In a case where the determination result of step S52 is “YES” (Tf≥Tfl), the processing proceeds to step S53.

[0169] In step S53, the controller 8 changes the shift position of the propulsion device 3 to the neutral position N (for example, time t12 in FIG. 11). Accordingly, the thrust of the propulsion device 3 becomes zero. That is, an increase in the boat speed V caused by the thrust of the propulsion device 3 is suppressed.

[0170] In a case where the determination result of step S53 is “NO” (Tf<Tfl), the processing proceeds to step S54.

[0171] In step S54, the controller 8 continues the shift position of the propulsion device 3 at the forward position F (for example, from time t11 to time t12 in FIG. 11). Accordingly, the thrust of the propulsion device 3 is continuously applied, and the boat speed V increases due to the thrust of the propulsion device 3.

[0172] In a case where the determination result in step S51 is “NO”, the current shift position is determined to be the neutral position N, and the processing proceeds to step S55.

[0173] In step S55, the controller 8 determines whether the duration of the neutral position N (neutral duration Tn) is equal to or longer than the neutral setting time Tnl. Note that the neutral duration Tn is measured by a timer provided in the controller 8. In the present embodiment, the neutral setting time Tnl is longer than the forward setting time Tfl. However, the neutral setting time Tnl may be equal to or shorter than the forward setting time Tfl.

[0174] In a case where the determination result of step S55 is “YES” (Tn≥Tnl), the processing proceeds to step S56.

[0175] In step S56, the controller 8 changes the shift position of the propulsion device 3 to the forward position F (for example, time t13 in FIG. 11). Accordingly, the thrust of the propulsion device 3 is applied, and thus the boat speed V increases (for example, times t13 to t14 in FIG. 11).

[0176] In a case where the determination result of step S55 is “NO” (Tn<Tnl), the processing proceeds to step S57.

[0177] In step S57, the controller 8 maintains the shift position of the propulsion device 3 at the neutral position N (for example, time t12 to t13 in FIG. 11). Accordingly, an increase in the boat speed V caused by the thrust of the propulsion device 3 is suppressed.

[0178] In the intermittent operation mode, by repeating the routine of the above-described intermittent control, it becomes possible to cruise the boat 1 while maintaining the boat speed V within the very slow speed region.

[0179] FIG. 13 is a flowchart showing the operation during the intermittent operation mode.

[0180] As illustrated in FIGS. 11 and 13, in step S61, the controller 8 determines whether the steering instruction angle θd is equal to or larger than the steering angle threshold θa.

[0181] In a case where the determination result of step S61 is “NO”, processing proceeds to Step s62 (θ<θa).

[0182] In step S62, the controller 8 sets “0” to the steering flag.

[0183] In a case where the determination result of step S61 is “YES”, the processing proceeds to step S63 (θ≥θa).

[0184] In step S63, the controller 8 sets “1” to the steering flag, and the processing proceeds to step S64.

[0185] In step S64, the controller 8 stops the intermittent control. In this situation, the controller 8 stores the position in the shift switching cycle at the time of stopping the intermittent control. In the example of FIG. 11, at time t15, in the shift switching cycle, a state in which the steering instruction angle θd is equal to or larger than the steering angle threshold θa before the neutral duration Tn reaches the neutral setting time Tnf is indicated. Therefore, the controller 8 stops the intermittent control partway through the neutral setting time Tnl.

[0186] In step S65, the controller 8 sets the shift position to the forward position F. Accordingly, the boat 1 cruises while increasing the boat speed V toward a desired course (the turning control).

[0187] In step S66, the controller 8 determines whether a state in which the steering flag is “0” is continuing for equal to or longer than a third predetermined time T3. The third predetermined time T3 is set to be longer than the control period and to be shorter than the shift switching cycle Ts. In the present embodiment, the third predetermined time T3 is preferably set to be shorter than at least the neutral setting time Tnl.

[0188] In a case where the determination result of step S66 is “NO”, the processing proceeds to step S67.

[0189] In step S67, the shift position is set to the forward position F. That is, in step S67, soon after the steering instruction angle θd returns to be smaller than the steering angle threshold θa, the shift position is continuously located at the forward position F (continuously conducting the turning control).

[0190] In a case where the determination result of step S66 is “YES”, the processing proceeds to step S68.

[0191] In step S68, the controller 8 determines whether the shift switching cycle Ts (the intermittent control) is temporarily stopped.

[0192] In a case where the determination result of step S68 is “YES”, the controller 8 calls, in step S69, the shift switching cycle Ts, which is stopped in step S64. The case where the determination result in step S69 is “YES” means, for example, a case where after the turning control returns to the intermittent control, a first cycle of the intermittent control is conducted, based on the shift switching cycle Ts. In this case, the intermittent control is restarted, based on the shift switching cycle Ts (a first cycle of the shift switching cycle Ts) at a stopped timing in accordance with the change to the turning control. Therefore, in step S69, information at the stopped timing about a previous time of the intermittent control is called.

[0193] Then, in step S70, the controller 8 restarts the intermittent control from the stopped timing due to changing to the turning control, in the shift switching cycle Ts (for example, time t16 in FIG. 11). That is, in the illustrated example, in a previous time of the intermittent control, the intermittent control is stopped partway through the neutral setting time Tnl. Therefore, in step S70, the intermittent control is restarted from the neutral position N, as the stopped timing in the previous time of the intermittent control. In this case, after an incomplete portion in the neutral setting time Tnl is completed, the shift position is switched to the forward position F (for example, time t17 in FIG. 11).

[0194] In a case where the determination result of step S68 is “NO”, the processing proceeds to step S71. The case where the determination result in step S68 is “NO” includes, for example, a case where after the turning control returns to the intermittent control, the first cycle of the shift switching cycle Ts elapses (a case where second and subsequent cycles of the intermittent control are conducted, based on the shift switching cycle Ts).

[0195] In step S71, the intermittent control is continued. That is, in step S71, since there is no incomplete shift switching cycle, the intermittent control illustrated in FIG. 6 continues.

[0196] In the propulsion system in the present embodiment, by switching the shift position between the forward position F and the neutral position N, based on the shift switching cycle in the intermittent operation mode, the controller 8 conducts the intermittent control of the thrust.

[0197] According to this constitution, by switching the shift position, based on the shift switching cycle that has been set beforehand, it becomes possible to simplify the control, as compared with a case of switching the shift position, based on the boat speed V.

[0198] In the propulsion system in the present embodiment, when changing to the intermittent control from the turning control, the controller 8 restarts the intermittent control from the stopped timing due to changing to the turning control in the shift switching cycle Ts in the previous time of the intermittent control.

[0199] According to this constitution, when returning to the intermittent control from the turning control, the intermittent control is restarted from a stopped state of a previous time, so that a sense of discomfort given to the user can be suppressed.Modification of Second Embodiment

[0200] In the above-described second embodiment, the constitution has been described in which a ratio occupied by the neutral setting time Tnl is larger than a ratio occupied by the forward setting time Tfl in the shift switching cycle. However, the present disclosure is not limited to this constitution. In one shift switching cycle, the lengths, ratios, and the like of the neutral setting time Tnl and the forward setting time Tfl can be appropriately changed.

[0201] In the above-described second embodiment, the constitution has been described in which the shift position is switched, based on one type of the shift switching cycle Ts in the intermittent control. However, the present disclosure is not limited to this constitution. The controller 8 may conduct the intermittent control by selecting one shift switching cycle Ts from a plurality of types of shift switching cycles Ts. In the plurality of types of shift switching cycles Ts, it is sufficient if at least one of the forward setting time Tfl and the neutral setting time Tnl are different from each other in each shift switching cycle Ts. In this case, the length of each shift switching cycle Ts itself may be equal or different.

[0202] In the constitution including the plurality of types of shift switching cycles Ts, the controller 8 is capable of selecting any one of the plurality of types of shift switching cycles Ts, based on, for example, the requested thrust Sd, the sea condition, or the like. In this case, for example, in a case where the requested thrust Sd is high, the controller 8 preferably selects the shift switching cycle Ts in which the ratio occupied by the neutral setting time Tnl is smaller in the shift switching cycle Ts than that in a case where the requested thrust Sd is low. Accordingly, the boat speed V is easily adjusted in accordance with the requested thrust Sd.Third Embodiment

[0203] A third embodiment is different from the second embodiment in that when the turning control returns to the intermittent control, the intermittent control is restarted from the start point of the shift switching cycle Ts. FIG. 14 is a timing chart showing the operation of the propulsion system. FIG. 15 is a flowchart showing the operation during the intermittent operation mode in the propulsion system.

[0204] In the propulsion system in the third embodiment illustrated in FIG. 14, in step S75, the controller 8 determines whether the steering instruction angle θd is equal to or larger than the steering angle threshold θa.

[0205] In a case where a determination result of step S75 is “NO”, processing proceeds to step S76 (θ<θa).

[0206] In step S76, the controller 8 sets “0” to the steering flag.

[0207] In a case where the determination result of step S75 is “YES”, the processing proceeds to step S77 (θ≥θa).

[0208] In step S77, the controller 8 sets “1” to the steering flag, and the processing proceeds to step S78.

[0209] In step S78, the controller 8 resets the record of the shift switching cycle Ts, which is being performed (reset history=1).

[0210] In step S79, the controller 8 sets the shift position to the forward position F. That is, the boat 1 cruises while increasing the boat speed V toward a desired course (the turning control), accordingly. Note that at time t21 in FIG. 14, a state in which the shift position of the intermittent control is the forward position F is changed to the turning control is indicated. Therefore, the shift position is maintained at the forward position F in accordance with the change to the turning control from the intermittent control.

[0211] In step S80, the controller 8 determines whether the reset history is “1”.

[0212] In a case where a determination result of step S80 is “NO”, the processing proceeds to step S81.

[0213] In step S81, the intermittent control illustrated in FIG. 6 continues, based on the shift switching cycle Ts. Note that the case where the determination result in step S80 denotes “NO” means, for example, a case where after the turning control returns to the intermittent control, the first cycle of the shift switching cycle Ts elapses (a case where the second and subsequent cycles of the intermittent control are conducted, based on the shift switching cycle Ts).

[0214] In a case where the determination result of step S80 is “YES”, the processing proceeds to step S82.

[0215] In step S82, the controller 8 determines whether a state in which the steering flag is “0” is continuing for equal to or longer than a third predetermined time T3.

[0216] In a case where the determination result of step S82 is “NO”, the processing proceeds to step S83.

[0217] In step S83, the controller 8 sets (maintains) the shift position to the forward position F.

[0218] In a case where a determination result of step S82 is “YES”, the processing proceeds to step S84.

[0219] In step S84, the controller 8 sets “0” to the reset history. That is, after the turning control, the controller 8 resets the record of the previous time of the intermittent control when returning to the intermittent control.

[0220] In step S85, the controller 8 restarts the intermittent control from the start point of the shift switching cycle (for example, time t22 in FIG. 14). In the present embodiment, the shift position at the start timing of the shift switching cycle Ts is set to the neutral position N.

[0221] In the propulsion system in the present embodiment, when returning to the intermittent control from the turning control, the controller 8 restarts the intermittent control from the start point of the shift switching cycle Ts.

[0222] According to this constitution, it is not necessary to store stopped information in the intermittent control, so that the control can be simplified. In addition, for example, by setting the shift position at the start timing of the shift switching cycle Ts to the neutral position N, it becomes possible to prevent an excessive increase in the boat speed V after the shift position is switched to the turning control from the intermittent control and then returns to the intermittent control again, in a case where the shift position is the forward position F.Modification of Third Embodiment

[0223] Also in the third embodiment, any shift switching cycle may be selected from a plurality of shift switching cycles in accordance with the requested thrust.

[0224] In the above-described third embodiment, the case where the start point of the shift switching cycle is the neutral position N has been described. However, the present disclosure is not limited to this constitution. The start point of the shift switching cycle may be the forward position F.Fourth Embodiment

[0225] FIG. 16 is a flowchart showing an operation method of the propulsion system according to a fourth embodiment. In the above-described embodiments, the constitution has been described in which each propulsion device 3 operates in synchronization in a case where a plurality of propulsion devices 3 are mounted. However, the present disclosure is not limited to this constitution. The fourth embodiment is different from the above-described embodiments in that operation timings of the plurality of propulsion devices 3 are made different from each other in the intermittent control, for example.

[0226] In the propulsion system in the present embodiment, out of the right propulsion device 3a and the left propulsion device 3b illustrated in FIG. 1, the propulsion device 3 (for example, the right propulsion device 3a) on one side belongs to a first propulsion device group 3, and the propulsion device 3 (for example, the left propulsion device 3b) on the other side belongs to a second propulsion device group 3. Hereinafter, for example, in the intermittent control illustrated in FIG. 5, a case where the shift position of the propulsion device 3 is switched to the forward position F from the neutral position N like step S16 will be described as an example.

[0227] As illustrated in FIG. 16, in step S90, the controller 8 determines whether change of the shift position (for example, change to the forward position F from the neutral position N) has been completed for the first propulsion device group 3.

[0228] In a case where a determination result of step S90 is “NO”, processing proceeds to step S91. In step S91, the controller 8 changes the shift position of the first propulsion device group 3.

[0229] In a case where the determination result of step S90 is “YES”, the processing proceeds to step S92. In step S92, the controller 8 determines whether the change of the shift position (for example, the change to the forward position F from the neutral position N) has been completed for the second propulsion device group 3.

[0230] In a case where the determination result of step S92 is “NO”, the processing proceeds to step S93. In step S93, the controller 8 changes the shift position of the second propulsion device group 3.

[0231] In a case where the determination result of step S92 is “YES”, it is determined that the change of the shift positions of all the propulsion devices 3 has been completed, and this routine ends.

[0232] In the propulsion system in the present embodiment, the controller 8 makes switching timings of the shift positions of the right propulsion device 3a and the left propulsion device 3b different from each other in the intermittent operation mode.

[0233] According to this constitution, vibrations or the like caused by the shift shock can be suppressed, as compared with a case where the shift positions are simultaneously switched for the respective propulsion devices 3. Accordingly, a sense of discomfort given to the user can be suppressed.Fifth Embodiment

[0234] FIG. 17 is a plan view of a boat 1 according to a fifth embodiment. In the above-described embodiments, the constitution has been described in which the absolute values of the right steering angle threshold θar and the left steering angle threshold θal are equal to each other. However, the present disclosure is not limited to this constitution. The absolute values of the right steering angle threshold θar and the left steering angle threshold θal may be different from each other.

[0235] In the boat 1 illustrated in FIG. 17, the controller 8 includes the right steering angle threshold θar and the left steering angle threshold θal respectively for the right propulsion device 3a and the left propulsion device 3b. For the right propulsion device 3a, the absolute value of the left steering angle threshold θal is set to be smaller than the absolute value of the right steering angle threshold θar. For the left propulsion device 3b, the absolute value of the right steering angle threshold θar is set to be smaller than the absolute value of the left steering angle threshold θal. In this case, the absolute value of the left steering angle threshold θal of the right propulsion device 3a is set to be smaller than the absolute value of the left steering angle threshold θal of the left propulsion device 3b. In addition, the absolute value of the right steering angle threshold θar of the left propulsion device 3b is set to be smaller than the absolute value of the right steering angle threshold θar of the right propulsion device 3a. That is, in the present embodiment, when the boat 1 makes a turn, the steering angle threshold θa of the propulsion device 3, which is located on an outer side, is set to be smaller than the steering angle threshold θa of the propulsion device 3, which is located on the inner side.

[0236] FIG. 18 is a plan view of the boat 1 at the time of turning to the right.

[0237] In the present embodiment, in the routine of step S25, whether the steering instruction angle θd is equal to or larger than the steering angle threshold θa is determined for each of the propulsion devices 3a and 3b. When turning to the right as illustrated in FIG. 18, the controller 8 determines whether the steering instruction angle θd is equal to or larger than the steering angle threshold θa in each of the propulsion devices 3a and 3b. In this case, the absolute value of the right steering angle threshold θar of the left propulsion device 3b is set to be smaller than the absolute value of the right steering angle threshold θar of the right propulsion device 3a. Therefore, the left propulsion device 3b is switched to the turning control from the intermittent control at a timing earlier than a timing of the right propulsion device 3a (a timing when the steering instruction angle θd is small).

[0238] FIG. 19 is a plan view of the boat 1 at the time of turning to the left.

[0239] When turning to the left as illustrated in FIG. 19, the controller 8 determines whether the steering instruction angle θd is equal to or larger than the left steering angle threshold θal in each of the propulsion devices 3a and 3b. In this case, the absolute value of the left steering angle threshold θal of the right propulsion device 3a is set to be smaller than the absolute value of the left steering angle threshold θal of the left propulsion device 3b. Therefore, the right propulsion device 3a is switched to the turning control from the intermittent control at a timing earlier than a timing of the left propulsion device 3b (a timing when the steering instruction angle θd is small).

[0240] In this manner, in the present embodiment, when the boat 1 makes a turn, the steering angle threshold θa of the propulsion device 3, which is located on an outer side, is set to be smaller than the steering angle threshold θa of the propulsion device 3, which is located on an inner side.

[0241] According to this constitution, when the boat 1 makes a turn, the propulsion device 3, which is located on the outer side, is switched to the turning control from the intermittent control earlier, so that the turning performance can be improved. In the present embodiment, the constitution has been described in which the absolute value of the right steering angle threshold θar and the absolute value of the left steering angle threshold θal are different from each other in accordance with the turning direction. However, the present disclosure is not limited to this constitution. Also, when changing the settings between the propulsion devices 3a and 3b in accordance with the rotation direction or trim angle of the propeller 22, the absolute value of the right steering angle threshold θar and the absolute value of the left steering angle threshold θal may be different from each other.Sixth Embodiment

[0242] FIG. 20 is a plan view of a boat 1 according to a sixth embodiment. A sixth embodiment is different from the above-described embodiments in that three or more propulsion devices 3 are provided.

[0243] The boat 1 illustrated in FIG. 20 includes four propulsion devices 103a to 103d. The four propulsion devices 103a to 103d include a right outer propulsion device 103a, a left outer propulsion device 103b, a right inner propulsion device 103c, and a left inner propulsion device 103d. The right outer propulsion device 103a is provided at a right end portion of the stern. The left outer propulsion device 103b is provided at a left end portion of the stern. The right inner propulsion device 103c is provided between the right outer propulsion device 103a and the left outer propulsion device 103b on the right side with respect to the center line CL. The left inner propulsion device 103d is provided between the right outer propulsion device 103a and the left outer propulsion device 103b on the left side with respect to the center line CL.

[0244] Like the present embodiment, in a case where three or more propulsion devices 103a to 103d are provided, only some of the propulsion devices 103a to 103d may be constituted to conduct the intermittent control in the intermittent operation mode.

[0245] In this case, for example, for the outer propulsion devices 103a and 103b, the shift positions may be switched between the forward position F and the neutral position N based on the intermittent control, whereas the inner propulsion devices 103c and 103d may fix the shift positions to the neutral position N. Accordingly, by generating thrust in the outer propulsion devices 103a and 103b, it becomes possible to improve the turning performance when the boat 1 makes a turn.

[0246] In addition, for the inner propulsion devices 103c and 103d, the shift positions may be switched between the forward position F and the neutral position N based on the intermittent control, whereas the outer propulsion devices 103a and 103b may fix the shift positions to the forward position F.[Other Modifications]

[0247] Heretofore, although preferred examples in the present disclosure have been described, the present disclosure is not limited to these examples. Additions, omissions, substitutions, and other changes of the constitution can be made without departing from the gist in the present disclosure. The present disclosure is not limited by the foregoing description, and is limited only by the appended claims.

[0248] In addition, as the type of the hull 2, the present disclosure may be applied to various moving bodies on water such as a V shape hull, a pontoon boat, a center console, a runabout, a fishing boat, and a jet ski.

[0249] In the above-described embodiments, the case where the drive source 12 is an internal combustion engine has been described. However, the present disclosure is not limited to this constitution. The drive source 12 may be an electric motor or the like. In a case of the electric motor, the motor rotation speed, torque, and the like correspond to “thrust”. In this case, the neutral position N is obtained by setting the motor rotation speed to zero.

[0250] When automatic driving or driving assistance (for example, cruise control as autopilot or constant-speed driving) is performed, a computer may be constituted to calculate an instruction value and set a target speed or the like, instead of the user (boat operator) inputting the “requested thrust Sd”.

[0251] In the above-described embodiments, the constitution has been described in which the intermittent control is conducted by switching the shift position between the forward position F and the neutral position N. However, the present disclosure is not limited to this constitution. The intermittent control may be conducted by switching between the forward position F and the reverse position R.

[0252] In the above-described embodiments, the intermittent operation mode has been described by using the forward movement of the boat 1 as an example. However, the present disclosure is not limited to this constitution. The intermittent operation mode may be conducted when the boat 1 moves rearward. In this case, as the intermittent control, the shift position may be switched between the reverse position R and the neutral position N, or the shift position may be switched between the reverse position R and the forward position F.

[0253] In the above-described embodiments, the constitution has been described in which the very slow speed cruising is enabled by switching the shift position in the intermittent operation mode. However, the present disclosure is not limited to this constitution. The intermittent operation mode may be achieved by fluctuation of the thrust within the identical shift position (the forward position F at the time of moving forward and the reverse position R at the time of moving rearward) based on the course of the boat 1.

[0254] In the above-described embodiments, the constitution of the boat 1 has been described by giving the case where the plurality of propulsion devices 3 are provided as an example. However, the present disclosure is not limited to this constitution. It is sufficient if at least one propulsion device is provided. In this case, a singular number of the propulsion device 3 may be provided.

[0255] In the above-described embodiments, the constitution has been described in which the valid state and the invalid state of the intermittent operation mode are switched by the operation on the operation unit 7. However, the present disclosure is not limited to this constitution. The intermittent operation mode may be always valid.

[0256] In the above-described embodiments, the constitution has been described in which the intermittent control and the turning control are switched, based on the steering instruction angle θd, while the intermittent operation mode is maintained. However, the present disclosure is not limited to this constitution. In the intermittent operation mode, it is sufficient if at least the intermittent control can be conducted. That is, when the intermittent control is changed to the turning control, the intermittent operation mode may be changed to the normal operation mode. In this case, the intermittent operation mode and the normal operation mode are switched, based on the steering instruction angle θd.

[0257] In the above-described embodiments, the constitution has been described in which the steering instruction angle θd is calculated, based on the operation amount on the steering angle inputter 4. However, the present disclosure is not limited to this constitution. The steering instruction angle θd may be constituted to be calculated, based on the operation amount on the steering angle inputter 4 per unit time. According to this constitution, the intermittent control is switched to the turning control, only when the output of the propulsion device 3 is necessary, such as at the time of suddenly making a turn. This makes it possible to improve fuel efficiency.

[0258] In addition, it is possible to appropriately replace any constituent element in the above-described embodiments with a known constituent element without departing from the gist in the present disclosure, and the above-described modifications may be appropriately combined together.

[0259] While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary examples of the invention and are not to be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the scope of the present invention. Accordingly, the invention is not to be considered as being limited by the foregoing description, and is only limited by the scope of the appended claims.REFERENCE SIGNS LIST1 Boat

[0261] 2 Hull

[0262] 3 Propulsion device

[0263] 3a Right propulsion device (propulsion device)

[0264] 3b Left propulsion device (propulsion device)

[0265] 4 Steering angle inputter

[0266] 5 Thrust inputter

[0267] 8 Controller

[0268] 12 Drive source

[0269] 14 Propulsor

[0270] 103a Right outer propulsion device

[0271] 103b Left outer propulsion device

[0272] 103c Right inner propulsion device

[0273] 103d Left inner propulsion device

[0274] Sd Requested thrust

[0275] Ts Shift switching cycle

[0276] V Boat speed

[0277] V1 First speed threshold

[0278] V2 Second speed threshold

[0279] θa Steering angle threshold

[0280] θal Left steering angle threshold

[0281] θar Right steering angle threshold

[0282] θd Steering instruction angle

Examples

first embodiment

Modifications of First Embodiment

[0154]In the above-described first embodiment, in the intermittent operation mode, when the steering instruction angle θd is equal to or larger than the steering angle threshold θa, the intermittent control is switched to the turning control. However, the present disclosure is not limited to this constitution. When the absolute value of the steering instruction angle θd is larger than 0 degrees, the intermittent control may be switched to the turning control.

[0155]In the above-described first embodiment, in the intermittent operation mode, the constitution has been described in which the intermittent control is switched to the turning control from the intermittent control, in a case where the steering instruction angle θd, which is equal to or larger than the steering angle threshold θa, is continuing for equal to or longer than the first predetermined time T1. However, the present disclosure is not limited to this constitution. When the steering ins...

second embodiment

Modification of Second Embodiment

[0200]In the above-described second embodiment, the constitution has been described in which a ratio occupied by the neutral setting time Tnl is larger than a ratio occupied by the forward setting time Tfl in the shift switching cycle. However, the present disclosure is not limited to this constitution. In one shift switching cycle, the lengths, ratios, and the like of the neutral setting time Tnl and the forward setting time Tfl can be appropriately changed.

[0201]In the above-described second embodiment, the constitution has been described in which the shift position is switched, based on one type of the shift switching cycle Ts in the intermittent control. However, the present disclosure is not limited to this constitution. The controller 8 may conduct the intermittent control by selecting one shift switching cycle Ts from a plurality of types of shift switching cycles Ts. In the plurality of types of shift switching cycles Ts, it is sufficient if ...

third embodiment

Modification of Third Embodiment

[0223]Also in the third embodiment, any shift switching cycle may be selected from a plurality of shift switching cycles in accordance with the requested thrust.

[0224]In the above-described third embodiment, the case where the start point of the shift switching cycle is the neutral position N has been described. However, the present disclosure is not limited to this constitution. The start point of the shift switching cycle may be the forward position F.

BACKGROUND OF THE INVENTIONField of the Invention

[0001] The present disclosure relates to a propulsion system of a boat.Description of Related Art

[0002] In recent years, efforts to provide access to sustainable transportation systems in consideration of vulnerable people among traffic participants are becoming active. In order to develop a sustainable transportation system, research and development for further improving traffic safety and convenience through, for example, driving support for boats are in progress. As one type of driving assistance of a boat, a constitution in which a shift position of an outboard motor is automatically switched to cruise the boat at a very slow speed (so-called auto-shift control) is known. For example, Patent Document 1 (Japanese Patent No. 6156926) discloses a constitution in which the shift position is switched between a forward position and a neutral position or between a reverse position and the neutral position every predetermined time.SUMMARY OF THE INVENTION

[0003] In the related art, however, there is still room for improvement in response performance at the time of making a turn, when changing the course of the boat during the auto-shift control.

[0004] The present disclosure provides a propulsion system of a boat capable of improving response performance at the time of making a turn. The present disclosure contributes to development of a sustainable transportation system, accordingly.

[0005] In order to solve the above-described problems, the present disclosure adopts the following aspects.

[0006] (1) A propulsion system of a boat, according to one aspect of the present disclosure, includes: at least one propulsion device provided on a hull, the at least one propulsion device including a drive source and a propulsor that generates thrust with dynamic power transmitted from the drive source; and a controller including at least a processor and a memory, the controller being configured to control the thrust of the propulsion device, in which the controller is capable of conducting intermittent control of intermittently changing the thrust of the at least one propulsion device, based on a condition for changing a boat speed, and turning control of causing the propulsion device to generate the thrust toward a course of the hull, based on an instruction value to be input into a steering angle inputter, when the steering angle inputter is operated during the intermittent control.

[0007] (2) In the propulsion system of the boat according to the above (1), during the intermittent control, the controller preferably switches to the turning control from the intermittent control, in a case where a steering instruction angle to the propulsion device based on the instruction value is equal to or larger than a steering angle threshold.

[0008] (3) In the propulsion system of the boat according to the above (1) or (2), during the intermittent control, the controller preferably continues the intermittent control, in a case where a steering instruction angle to the propulsion device based on the instruction value is smaller than the steering angle threshold.

[0009] (4) In the propulsion system of the boat according to the above (2) or (3), during the intermittent control, the controller preferably switches to the turning control from the intermittent control, in a case where a state in which the steering instruction angle is equal to or larger than the steering angle threshold continues for a time equal to or longer than a first predetermined time.

[0010] (5) In the propulsion system of the boat according to one of the above (2) to (4), during the turning control, the controller preferably switches to the intermittent control from the turning control, in a case where a state in which the steering instruction angle is smaller than the steering angle threshold continues for a time equal to or longer than a second predetermined time.

[0011] (6) In the propulsion system of the boat according to the above (4), during the intermittent control, the controller preferably switches to the turning control from the intermittent control, in a case where a state in which the steering instruction angle is equal to or larger than the steering angle threshold continues for a time equal to or longer than a first predetermined time, during the turning control, the controller preferably switches to the intermittent control from the turning control, in a case where a state in which the steering instruction angle is smaller than the steering angle threshold continues for a time equal to or longer than a second predetermined time, and the second predetermined time is set to be longer than the first predetermined time.

[0012] (7) In the propulsion system of the boat according to one of the above (2) to (6), the steering angle threshold preferably includes: a right steering angle threshold for changing the course of the hull to a right side with respect to a straight advancing direction; and a left steering angle threshold for changing the course of the hull to a left side with respect to the straight advancing direction.

[0013] (8) In the propulsion system of the boat according to the above (7), absolute values of the right steering angle threshold and the left steering angle threshold are preferably set to be equal to each other.

[0014] (9) In the propulsion system of the boat according to one of the above (1) to (8), the controller preferably controls a shift position of the propulsion device, based on a requested shift position that has been input into a thrust inputter, and also controls the dynamic power of the drive source, based on requested thrust that has been input into the thrust inputter, the controller is preferably capable of conducting: a normal operation mode of controlling the dynamic power of the drive source, based on the requested thrust, in a case where the requested shift position is a forward position and the dynamic power of the drive source based on the requested thrust is other than being larger than a minimum output value; and an intermittent operation mode of conducting at least the intermittent control, in a case where the requested shift position is the forward position and the dynamic power of the drive source based on the requested thrust is a minimum output value of the drive source, and the intermittent control preferably changes the shift position between the forward position and a neutral position in a state in which the dynamic power of the drive source is kept constant.

[0015] (10) In the propulsion system of the boat according to the above (9), the controller preferably sets the shift position to the forward position at a start timing of the intermittent control.

[0016] (11) In the propulsion system of the boat according to the above (9) or (10), the condition for changing the boat speed is preferably the boat speed, and during the intermittent control, the controller preferably sets the shift position to the neutral position from the forward position, in a case where the boat speed is equal to or higher than a first speed threshold.

[0017] (12) In the propulsion system of the boat according to the above (11), during the intermittent control, the controller preferably sets the shift position to the forward position from the neutral position, in a case where the boat speed is equal to or lower than a second speed threshold, the second speed threshold being smaller than the first speed threshold.

[0018] (13) In the propulsion system of the boat according to one of the above (9) to (12), the condition for changing the boat speed is preferably at least one type of shift switching cycle that has been set in combination of a forward setting time while the forward position continues and a neutral setting time while the neutral position continues, and during the intermittent control, the controller preferably switches the shift position between the forward position and the neutral position, based on the shift switching cycle.

[0019] (14) In the propulsion system of the boat according to the above (13), during the intermittent control, the controller preferably switches to the turning control from the intermittent control, in a case where a steering instruction angle to the propulsion device based on the instruction value is equal to or larger than a steering angle threshold, during the intermittent control, the controller preferably switches to the intermittent control from the turning control, in a case where the steering instruction angle is smaller than the steering angle threshold, and when changing to the intermittent control from the turning control, the controller preferably restarts the intermittent control from a stopped timing due to changing to the turning control in the shift switching cycle of a previous time of the intermittent control.

[0020] (15) In the propulsion system of the boat according to the above (13) or (14), during the intermittent control, the controller preferably switches to the turning control from the intermittent control, in a case where a steering instruction angle to the propulsion device based on the instruction value is equal to or larger than a steering angle threshold, during the intermittent control, the controller preferably switches to the intermittent control from the turning control, in a case where the steering instruction angle is smaller than the steering angle threshold, the controller preferably sets the shift position of a start timing of the shift switching cycle to the neutral position, and when changing to the intermittent control from the turning control, the controller preferably conducts the intermittent control from the start timing of the shift switching cycle.

[0021] (16) In the propulsion system of the boat according to one of the above (13) to (15), a plurality of types of the shift switching cycles in which at least one of the neutral setting time and the forward setting time is different are preferably provided, and the controller preferably conducts the intermittent control, based on one of the plurality of types of the shift switching cycles.

[0022] (17) In the propulsion system of the boat according to one of the above (9) to (16), the at least one propulsion device preferably includes: a left propulsion device provided on a left side with respect to a center in a left-right direction of the hull; and a right propulsion device provided on a right side with respect to the center in the left-right direction, and the controller preferably makes switching timings of the shift positions of the left propulsion device and the right propulsion device different from each other in the intermittent control.

[0023] (18) In the propulsion system of the boat according to one of the above (9) to (16), the at least one propulsion device preferably includes: a left propulsion device provided on a left side with respect to a center in a left-right direction of the hull; and a right propulsion device provided on a right side with respect to the center in the left-right direction, during the intermittent control, the controller preferably switches to the turning control from the intermittent control, in a case where a steering instruction angle based on the instruction value is equal to or larger than a steering angle threshold, the steering angle threshold preferably includes: a right steering angle threshold for changing the course of the hull to the right side with respect to a straight advancing direction; and a left steering angle threshold for changing the course of the hull to the left side with respect to the straight advancing direction, an absolute value of the right steering angle threshold of the left propulsion device is preferably set to be smaller than an absolute value of the right steering angle threshold of the right propulsion device, and an absolute value of the left steering angle threshold of the right propulsion device is preferably set to be smaller than an absolute value of the left steering angle threshold of the left propulsion device.

[0024] (19) In the propulsion system of the boat according to one of the above (1) to (16), the at least one propulsion device preferably includes: outer propulsion devices provided at both end portions of the hull in a left-right direction; and at least one inner propulsion device provided between the outer propulsion devices, and the controller preferably causes any of the outer propulsion devices and the inner propulsion device to conduct the intermittent control.

[0025] (20) In the propulsion system of the boat according to the above (19), the controller preferably sets a shift position of the inner propulsion device to a neutral position, when conducting the intermittent control on the outer propulsion devices.

[0026] (21) In the propulsion system of the boat according to the above (20), the controller preferably sets a shift position of the outer propulsion devices to a forward position, when conducting the intermittent control on the inner propulsion device.

[0027] (22) In the propulsion system of the boat according to one of the above (1) to (21), the instruction value is preferably an operation amount on the steering angle inputter.

[0028] (23) In the propulsion system of the boat according to one of the above (1) to (21), the instruction value is preferably an operation amount on the steering angle inputter per unit time.

[0029] According to the above aspects, response performance at the time of making a turn can be improved.BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG. 1 is a plan view of a boat according to a first embodiment;

[0031] FIG. 2 is a side view illustrating a propulsion device;

[0032] FIG. 3 is a block diagram of the boat;

[0033] FIG. 4 is a state transition diagram illustrating switching to and from an intermittent operation mode;

[0034] FIG. 5 is a timing chart showing the operation of a propulsion system according to the first embodiment;

[0035] FIG. 6 is a flowchart showing intermittent control (auto-shift control) during an intermittent operation mode in the propulsion system according to the first embodiment;

[0036] FIG. 7 is a flowchart showing a switching operation between the intermittent operation mode and a normal operation mode in the propulsion system according to the first embodiment;

[0037] FIG. 8 is a flowchart showing the operation during the intermittent operation mode;

[0038] FIG. 9 is a diagram illustrating a relationship between a steering angle threshold and a shift position;

[0039] FIG. 10 is a plan view of the boat at the time of turning control (turning to the right) according to the first embodiment;

[0040] FIG. 11 is a timing chart showing the operation of the propulsion system according to a second embodiment;

[0041] FIG. 12 is a flowchart showing a shift switching operation during an intermittent operation mode in the propulsion system according to the second embodiment;

[0042] FIG. 13 is a flowchart showing the operation during the intermittent operation mode in the propulsion system according to the second embodiment;

[0043] FIG. 14 is a timing chart showing the operation of the propulsion system according to a third embodiment;

[0044] FIG. 15 is a flowchart showing a switching operation between the intermittent operation mode and the normal operation mode and a turning operation during the intermittent operation mode in the propulsion system according to the third embodiment;

[0045] FIG. 16 is a flowchart showing an operation method of the propulsion system according to a fourth embodiment;

[0046] FIG. 17 is a plan view of a boat according to a fifth embodiment;

[0047] FIG. 18 is a plan view showing the operation of the boat according to the fifth embodiment at the time of turning to the right;

[0048] FIG. 19 is a plan view showing the operation of the boat according to the fifth embodiment at the time of turning to the left; and

[0049] FIG. 20 is a plan view of a boat according to a sixth embodiment.DETAILED DESCRIPTION OF THE INVENTION

[0050] Hereinafter, embodiments in the present disclosure will be described with reference to the drawings. In embodiments and modifications to be described below, corresponding constitutions are denoted by the same reference numbers, and descriptions will be omitted, in some cases. In the following description, for example, expressions indicating relative or absolute arrangements such as “parallel”, “orthogonal”, “center”, and “coaxial” represent not only strictly such arrangements but also a state of being relatively displaced with a tolerance or with an angle or a distance with which the same function is obtainable. In addition, in the present embodiment, “face each other” is not limited to a case where the orthogonal directions (normal directions) of two surfaces coincide with each other, and includes a case where the orthogonal directions intersect each other.

[0051] It is assumed that front, rear, upper, lower, left, and right directions in the following description respectively coincide with the directions of a boat 1. In this case, an arrow FR in the drawing indicates a forward side of the boat 1, an arrow UP in the drawing indicates an upper side of the boat 1, and an arrow LH in the drawing indicates a leftward side of the boat 1. In addition, a center line CL indicates the center position of the boat 1 in a left-right direction (a width direction).First Embodiment[Boat 1]

[0052] FIG. 1 is a plan view of a boat 1 according to a first embodiment.

[0053] The boat 1 illustrated in FIG. 1 includes a hull 2, a plurality of propulsion devices 3, a steering angle inputter 4, a thrust inputter 5, a boat speed sensor 6 (see FIG. 3), an operation unit 7, and a controller 8. Noe that the plurality of propulsion devices 3 and the controller 8 constitute a propulsion system according to the present embodiment.<Propulsion Device 3>

[0054] The propulsion device 3 includes: a right propulsion device 3a, which is provided on the right side of the stern with respect to the center line CL; and a left propulsion device 3b, which is provided on the left side of the stern with respect to the center line CL. That is, the boat 1 in the present embodiment is a so-called small-sized vessel in which the two propulsion devices 3 (the right propulsion device 3a and the left propulsion device 3b) are provided at both left and right end portions of the stern with the center line CL interposed between them. Hereinafter, in a case where it is not necessary to distinguish between the propulsion devices 3a and 3b, they will be collectively described as the propulsion device 3.

[0055] FIG. 2 is a side view of the propulsion device 3. FIG. 3 is a block diagram of the boat 1.

[0056] As illustrated in FIGS. 2 and 3, the propulsion device 3 is, for example, an outboard motor. The propulsion device 3 includes: a casing 11; a drive source 12; a drive shaft 13; a propulsor 14; and a shift switching mechanism 15.

[0057] The casing 11 is attached to a bracket 9, which is provided at the stern, via a steering shaft (swivel shaft) 16, which extends in an up-down direction. The propulsion device 3 is attached to the hull 2 so as to be rotatable around a steering shaft 16 in accordance with the operation on a steering actuator 17 (see FIG. 3).

[0058] The drive source 12 is, for example, an internal combustion engine such as an engine. The drive source 12 is accommodated in an upper portion of the casing 11 with a crankshaft extending in the up-down direction. Dynamic power (engine speed) of the drive source 12 is set, based on an opening degree of a throttle valve. The throttle valve is driven by the operation of a throttle actuator 18 (see FIG. 3).

[0059] The drive shaft 13 transmits the dynamic power generated by the drive source 12 to the propulsor 14 via the shift switching mechanism 15. The drive shaft 13 extends in the up-down direction in the casing 11. An upper end portion of the drive shaft 13 is connected with the drive source 12.

[0060] The propulsor 14 includes a propeller shaft 21 and propellers 22.

[0061] The propeller shaft 21 is provided at a lower end portion of the casing 11 so as to be rotatable around an axis along a front-rear direction. A front end portion of the propeller shaft 21 is connected with the shift switching mechanism 15 in the casing 11.

[0062] The propellers 22 are provided projecting on the outside of the casing 11 at a rear end portion of the propeller shaft 21. The propellers 22 rotate integrally with the propeller shaft 21.

[0063] The shift switching mechanism 15 includes a drive gear 25, a forward gear 26, a reverse gear 27, and a clutch 28.

[0064] The drive gear 25 is provided at a lower end portion of the drive shaft 13. The drive gear 25 is rotatable integrally with the drive shaft 13.

[0065] The forward gear 26 and the reverse gear 27 are rotatably provided at positions that face each other in the front-rear direction interposing the drive gear 25 on the propeller shaft 21. The forward gear 26 and the reverse gear 27 mesh with the drive gear 25. The forward gear 26 and the reverse gear 27 rotate in opposite directions in accordance with the rotation of the drive gear 25.

[0066] The clutch 28 switches a connection state or a disconnection state of the dynamic power between either the forward gear 26 or the reverse gear 27 and the propeller shaft 21. The clutch 28 is provided in a part, positioned between the forward gear 26 and the reverse gear 27, of the propeller shaft 21 so as to be rotatable integrally with the propeller shaft 21. The clutch 28 is provided to be movable in the front-rear direction along the propeller shaft 21 in accordance with the operation of a shift actuator 29. The clutch 28 meshes with the forward gear 26, and is capable of transmitting the rotational force of the forward gear 26 to the propeller shaft 21 (a forward position F). This causes the propellers 22 to rotate in the normal rotation direction, thereby applying thrust in a forward advancing direction to the boat 1. The clutch 28 meshes with the reverse gear 27, and is capable of transmitting the rotational force of the reverse gear 27 to the propeller shaft 21 (a reverse position R). This causes the propellers 22 to rotate in the reverse rotation direction, thereby applying thrust in a rearward advancing direction to the boat 1. On the other hand, in a state in which the clutch 28 does not mesh with either the forward gear 26 or the reverse gear 27, the rotational force is not transmitted to the propeller shaft 21 (a neutral position N).<Steering Angle Inputter 4>

[0067] As illustrated in FIGS. 1 and 3, the steering angle inputter 4 is provided in a cockpit of the hull 2. The steering angle inputter 4 is, for example, a steering wheel provided rotatably to the left and right. The steering angle inputter 4 receives an operation of a user when changing the course of the boat 1 (hull 2). That is, the steering angle inputter 4 receives an operation for changing the direction (a steering angle θ) of the propulsion device 3 around the steering shaft 16. The steering angle θ denotes an inclination angle of the propulsion device 3 with respect to a center line CL in a plan view. In the present embodiment, the steering angle θ of the propulsion device 3, in a state in which the propeller shaft 21 is parallel to the center line CL in a plan view, is set as a reference value (0 degrees). An operation amount in accordance with the rotation operation on the steering angle inputter 4 is detected by a steering angle sensor 31. The steering angle sensor 31 outputs a detection signal based on an operation amount on the steering angle inputter 4 to the controller 8, as an instruction value. Note that as the steering angle inputter 4, in addition to the steering wheel, a joystick may be used, and the steering angle inputter 4 may be mounted as a switch or the like of the operation unit 7.<Thrust Inputter 5>

[0068] The thrust inputter 5 is provided in the cockpit of the hull 2. The thrust inputter 5 is, for example, a throttle lever (accelerator lever). The thrust inputter 5 receives the operation of a user when changing the thrust of the propulsion device 3 (requested thrust Sd) or the shift position of the propulsion device 3 (requested shift position). The thrust inputter 5 is capable of reciprocating in an operation area in which three shift areas of the forward position F, the neutral position N, and the reverse position R are aligned in accordance with rotation, sliding, or the like. Note that in the present embodiment, the propulsion device 3 will be described using an outboard motor as an example, but the present disclosure is not limited to this constitution. In addition to the outboard motor, the propulsion device may be an inboard motor, an inboard and outboard motor, a water jet machine, or the like. For example, in a case of the inboard motor, the direction of the thrust of the propulsion device 3 may be changed by changing the direction of a separately provided rudder. For example, in a case of the water jet machine, the direction of the thrust of the propulsion device 3 may be changed by changing the direction of a water flow. Further, the outboard motor and a side thruster may be combined together to constitute the propulsion device 3. In this case, the direction of the thrust of the propulsion device 3 may be changed by the ratio between the thrust of the outboard motor and the thrust of the side thruster.

[0069] In the boat 1, it is possible to set the requested shift position in accordance with the position of the thrust inputter 5 in the operation area. That is, in a case where the thrust inputter 5 is located in the shift area of the forward position F, it is possible to request the controller 8 to set the shift position to the forward position F. In a case where the thrust inputter 5 is located in the shift area of the neutral position N, it is possible to request the controller 8 to set the shift position to the neutral position N. In a case where the thrust inputter 5 is located in the shift area of the reverse position R, it is possible to request the controller 8 to set the shift position to the reverse position R.

[0070] In the boat 1, it is possible to set the requested thrust in accordance with the position of the thrust inputter 5 in the operation area. That is, in a case where the thrust inputter 5 is located in the shift area of the neutral position N, it is possible to request the controller 8 to set the thrust to zero. In a case where the thrust inputter 5 is set in the shift area of the forward position F or the reverse position R, it is possible to request the controller 8 to increase the thrust in the corresponding advancing direction, as the thrust inputter 5 is apart from the shift area of the neutral position N. The position (a lever opening rate LE) of the thrust inputter 5 is detected by a position sensor 32. The position sensor 32 outputs, to the controller 8, a detection signal based on the position (the lever opening rate LE) of the thrust inputter 5.<Boat Speed Sensor 6>

[0071] As illustrated in FIG. 3, the boat speed sensor 6 detects a speed (boat speed) V of the boat 1. The boat speed sensor 6 receives a positioning signal from a positioning satellite such as a global positioning system (GPS), for example, measures an absolute position (latitude, longitude) of the boat 1, based on the received positioning signal, and calculates the boat speed (the boat speed relative to the ground) V, based on time-series positioning results. The boat speed sensor 6 may be an acoustic sensor or an electromagnetic sensor that detects the boat speed (the boat speed relative to the water) V of the boat 1. The boat speed sensor 6 may estimate the boat speed V, based on the engine speed. Note that a plurality of the speed sensors 6 may be used in combination.<Operation Unit 7>

[0072] The operation unit 7 receives various operations in the boat 1. The operation unit 7 is constituted to be manually operable by a user, such as a multi-function display (MFD). Note that the operation unit 7 may be an external device such as a mobile terminal connected to the boat 1 in a wired or wireless manner.

[0073] FIG. 4 is a state transition diagram illustrating switching between a normal operation mode and an intermittent operation mode.

[0074] As illustrated in FIG. 4, in the boat 1 in the present embodiment, an intermittent operation mode (an auto-shift mode) and a normal operation mode (a normal navigation mode) are switched in accordance with the operation on the thrust inputter 5, for example.

[0075] The intermittent operation mode is a mode of cruising the boat 1 in a very slow speed region within a predetermined speed range (for example, the speed may be approximately 2 km / h to approximately 4 km / h or may be slower than it). The intermittent operation mode is applied when the thrust (the requested thrust Sd) generated by the propulsion device 3 is, for example, equal to or smaller than the thrust to be output at the minimum output value (rotation speed at the time of idling) of the drive source 12. In the intermittent operation mode, for example, when the boat 1 moves forward (the requested shift position is the forward position F), the shift position is automatically switched between the forward position F and the neutral position N. Accordingly, in the intermittent operation mode, it becomes possible to cruise the boat 1 at the boat speed V, which is achievable with equal to or smaller than the thrust to be output at the minimum output value of the drive source 12.

[0076] The normal operation mode is a mode of cruising the boat 1 in a speed region (a normal speed region) other than the very slow speed region. The normal operation mode is applied when the thrust (the requested thrust Sd) generated by the propulsion device 3 is larger than the thrust to be output at the minimum output value of the drive source 12, for example. In the normal operation mode, for example, when the boat 1 moves forward, output (a throttle opening degree φ) of the drive source 12 is adjusted in accordance with the position (the lever opening rate LE) of the thrust inputter 5, and thus the thrust generated by the propulsion device 3 is adjusted. Note that in the present embodiment, it is possible to select whether the switching control between the intermittent operation mode and the normal operation mode is set to a valid state or an invalid state, by using, for example, the operation (ON / OFF operation) on the operation unit 7.<Controller 8>

[0077] The controller 8 integrally controls the operation of the boat 1 (the propulsion device 3). The controller 8 is an integrated or a plurality of electronic control devices included in the boat 1. The controller 8 is implemented by, for example, a hardware processor such as a central processing unit (CPU) executing a program (software) stored in a read only memory (ROM), a random access memory (RAM), or the like. Some or all of these constituent elements may be implemented by a hardware (a circuit part; including circuitry) such as a large scale integration (LSI), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a graphics processing unit (GPU), or system on chip (SOC) or may be implemented by software and hardware in cooperation.

[0078] The controller 8 includes a storage 60, an acquisitor 61, a determiner 62, and a drive processor 63.

[0079] The storage 60 includes, for example, a ROM or the like. In the storage 60, for example, programs, various data, and the like necessary for cruising the boat 1, such as the intermittent operation mode and the normal operation mode, are stored.

[0080] The acquisitor 61 includes, for example, a RAM or the like. The acquisitor 61 acquires detection results of various sensors.

[0081] The determiner 62 includes, for example, a CPU or the like. The determiner 62 determines the state of the boat 1, based on information obtained by the acquisitor 61 and information stored in the storage 60.

[0082] The drive processor 63 includes, for example, a CPU or the like. The drive processor 63 controls the operation of various actuators, based on a determination result in the determiner 62 and the information stored in the storage 60 or the acquisitor 61, and also controls the operation of the engine such as fuel injection or ignition by a known ECU provided in the propulsion device 3.[Operation Method of Propulsion System]

[0083] Next, an operation method of the propulsion system will be described. Hereinafter, the switching operation between the intermittent operation mode and the normal operation mode, and a turning operation during the intermittent operation mode when the boat 1 moves forward (the requested shift position is the forward movement position F) will be mainly described. Processing to be described below is repeatedly performed, for example, at a predetermined control cycle (for example, several tens of [msec]).

[0084] FIG. 5 is a timing chart showing the operation of the propulsion system. FIG. 6 is a flowchart showing intermittent control (the auto-shift control) during the intermittent operation mode in the propulsion system.

[0085] As illustrated in FIGS. 5 and 6, in step S11, the controller 8 determines whether the current shift position is the forward position F, based on a detection result of the position sensor 32 (for example, time t1 in FIG. 5).

[0086] In a case where the determination result of step S11 is “YES”, it is determined that the current shift position is the forward position F, and processing proceeds to step S12.

[0087] In step S12, the controller 8 determines whether the boat speed V is equal to or higher than a first speed threshold V1, based on a detection result of the boat speed sensor 6. The first speed threshold V1 is, for example, an upper limit value of the very slow speed region (a boundary value between the very slow speed region and a normal speed region). In this case, the first speed threshold V1 is preferably smaller than the boat speed V, which is achievable with the minimum output value of the drive source 12 (the minimum value of the throttle opening degree φ). However, the first speed threshold V1 may be appropriately set by utilizing actual travel data.

[0088] In a case where the determination result of step S12 is “YES” (V≥V1), the processing proceeds to step S13. That is, in the case where the determination result of step S12 is “YES”, it is determined that the thrust deviates from the very slow speed region against the requested thrust Sd or there is a possibility of deviating from the very slow speed region (for example, time t2 in FIG. 5).

[0089] In step S13, the controller 8 changes the shift position of the propulsion device 3 to the neutral position N. Accordingly, the thrust of the propulsion device 3 becomes zero. That is, an increase in the boat speed V caused by the thrust of the propulsion device 3 is suppressed (for example, time t2 to time t3 in FIG. 5).

[0090] In a case where the determination result of step S12 is “NO” (V<V1), the processing proceeds to step S14. That is, in the case where the determination result in step S12 is “NO”, it is determined that the boat is cruising in the very slow speed region, based on the requested thrust Sd.

[0091] In step S14, the controller 8 continues the shift position of the propulsion device 3 at the forward position F. Accordingly, the thrust of the propulsion device 3 is continuously applied, and the boat speed V increases due to the thrust of the propulsion device 3.

[0092] In a case where the determination result in step S11 is “NO”, it is determined that the current shift position is the neutral position N, and the processing proceeds to step S15.

[0093] In step S15, it is determined whether the boat speed V is equal to or lower than a second speed threshold V2. The second speed threshold V2 is a lower limit value of the very slow speed region.

[0094] In a case where the determination result of step S15 is “YES” (V≤V2), the processing proceeds to step S16. That is, in the case where the determination result in step S15 is “YES”, the controller 8 determines that the vehicle deviates from the very slow speed region against the requested thrust or there is a possibility of deviating from the very slow speed region (for example, time t3 in FIG. 5).

[0095] In step S16, the controller 8 changes the shift position of the propulsion device 3 to the forward position F. Accordingly, the thrust of the propulsion device 3 is applied, and thus the boat speed V increases (for example, time t3 to time t4 in FIG. 5).

[0096] In a case where the determination result of step S15 is “NO” (V>V2), the processing proceeds to step S17. That is, in the case where the determination result in step S16 is “NO”, the controller 8 determines that the vehicle is cruising in the very slow speed region, based on the requested thrust Sd.

[0097] In step S17, the controller 8 maintains the shift position of the propulsion device 3 at the neutral position N. Accordingly, an increase in the boat speed V caused by the thrust of the propulsion device 3 is suppressed.

[0098] In the intermittent operation mode, by repeating the routine of the above-described intermittent control, it becomes possible to cruise the boat 1 while maintaining the boat speed V within the very slow speed region.

[0099] FIG. 7 is a flowchart showing a switching operation between the intermittent operation mode and the normal operation mode in the propulsion system.

[0100] As illustrated in FIG. 7, in step S21, the controller 8 determines whether the shift position is the forward position F and the requested thrust Sd is equal to or smaller than the thrust to be output at the minimum output value of the drive source 12.

[0101] In a case where a determination result of step S21 is “NO”, the processing proceeds to step S22. That is, in the case where the determination result in step S21 is “NO”, the controller 8 determines that the shift position is other than the forward position F or the requested thrust Sd is larger than the thrust to be output at the minimum output value of the drive source 12.

[0102] In step S22, the controller 8 performs the normal operation mode. In the normal operation mode, the output (the throttle opening degree φ) of the drive source 12 is adjusted in accordance with the position (the lever opening rate LE) of the thrust inputter 5, and thus the thrust generated by the propulsion device 3 is adjusted. Accordingly, the boat 1 cruises at the boat speed V corresponding to the requested thrust by the user.

[0103] In a case where a determination result of step S21 is “YES”, the processing proceeds to step S23. That is, in the case where the determination result of step S21 is “YES”, the controller 8 determines that the shift position is the forward position F and the requested thrust Sd is equal to or smaller than the thrust to be output at the minimum output value of the drive source 12.

[0104] FIG. 8 is a flowchart showing the operation during the intermittent operation mode.

[0105] As illustrated in FIGS. 5 and 8, in step S25, the controller 8 determines whether a steering instruction angle θd is equal to or larger than a steering angle threshold θa. The steering instruction angle θd is calculated from a map or the like stored beforehand in the storage 60, based on, for example, an operation amount on the steering angle inputter 4, and is the steering angle θ of the propulsion device 3 necessary for the boat 1 to make a turn in response to a steering request of the user. The controller 8 rotates the propulsion device 3 around the steering shaft 16, based on the steering instruction angle θd that has been calculated.

[0106] FIG. 9 is a diagram illustrating a relationship between the steering angle threshold θa and a shift position.

[0107] As illustrated in FIG. 9, the steering angle threshold θa includes a right steering angle threshold θar, which is a threshold for a direction of causing the boat 1 to turn to the right with respect to a straight advancing direction, and a left steering angle threshold θal, which is a threshold for a direction of causing the boat 1 to turn to the left with respect to the straight advancing direction. In the present embodiment, the absolute values of the right steering angle threshold θar and the left steering angle threshold θal are set to be equal to each other.

[0108] In a case where a determination result of step S25 is “YES”, the processing proceeds to step S26 (θ≥θa). That is, in the case where the determination result in step S25 is “YES”, the controller 8 determines that the turning angle of the boat 1 is large (for example, time t5 in FIG. 5).

[0109] In step S26, the controller 8 sets “1” to the steering flag, and the processing proceeds to step S27. Note that in a case where the steering instruction angle θd is smaller than the steering angle threshold θa, the steering flag is “0”, and in a case where the steering angle θ is equal to or larger than the steering angle threshold θa, the steering flag is “1”.

[0110] In step S27, the controller 8 determines whether a state in which the steering flag is “1” is continuing for equal to or longer than a first predetermined time T1. The first predetermined time T1 is set to be equal to a control cycle, for example.

[0111] In a case where the determination result of step S27 is “NO”, the processing proceeds to step S28, and the intermittent control illustrated in FIG. 6 continues.

[0112] In a case where the determination result of step S27 is “YES”, the processing proceeds to step S29.

[0113] FIG. 10 is a plan view of the boat 1 at the time of turning control (turning to the right).

[0114] As illustrated in FIGS. 5, 8, and 10, in step S29, the controller 8 sets the shift position to the forward position F (for example, time t6 in FIG. 5). That is, during the intermittent operation mode, upon determination that the turning angle of the boat 1 is large, the controller 8 sets the shift position to the forward position F regardless of the boat speed V (the turning control). Accordingly, the boat 1 cruises while increasing the boat speed V toward a desired course.

[0115] As illustrated in FIGS. 5 and 8, in a case where the determination result of step S25 is “NO”, the processing proceeds to step S30 (θ<θa). That is, in the case where the determination result in step S25 is “NO”, the controller 8 determines that the course of the boat 1 remains straight or the turning angle is small.

[0116] In step S30, the controller 8 sets “0” to the steering flag, and the processing proceeds to step S31. Note that in a case where the steering flag is “0”, a shift switching operation (the intermittent control) is performed, based on the boat speed V as described above in the intermittent operation mode.

[0117] In step S31, the controller 8 determines whether a state in which the steering angle flag is “0” is continuing for equal to or longer than a second predetermined time T2 (for example, between times t7 and t8 in FIG. 5). The second predetermined time T2 is set to be longer than the first predetermined time T1 (for example, 1 sec).

[0118] In a case where a determination result of step S31 is “NO”, the processing proceeds to step S32.

[0119] In step S32, the controller 8 continues the shift position of the propulsion device 3 at the forward position F. Note that in step S32, for example, during the turning control, in a case where the steering angle θ has just returned to be smaller than the steering angle threshold θa, the shift position at the forward position F continues (the turning control continues).

[0120] In a case where the determination result of step S31 is “YES”, the processing proceeds to step S33.

[0121] In step S33, the controller 8 conducts the intermittent control illustrated in FIG. 6. Note that at time t8, since the current shift position is the forward position F and the boat speed V is smaller than the first speed threshold V1, the shift position at the forward position F continues, even though the control returns to the intermittent control.

[0122] Then, at time t9, by setting the requested shift position to the neutral position N (the requested thrust Sd is zero), the shift position of each propulsion device 3 becomes the neutral position N.

[0123] As illustrated in FIG. 4, during the intermittent operation mode, in a case where the shift position is the forward position F, when both of the following cases (1-1) and (1-2) are satisfied, the shift position is switched to the neutral position N from the forward position F.

[0124] (1-1) A case where the boat speed V is equal to or higher than the first speed threshold V1 during the intermittent control.

[0125] (1-2) A case where during the turning control, after the steering instruction angle θd returns to be smaller than the steering angle threshold θa, a state of being smaller than the steering angle threshold θa is continuing for the second predetermined time T2 (switching to the intermittent control from the turning control).

[0126] During the intermittent operation mode, when the shift position is the neutral position N, the shift position is switched to the forward position F from the neutral position N in any one of the following cases (2-1) and (2-2).

[0127] (2-1) A case where the boat speed is equal to or lower than the second speed threshold V2 during the intermittent control.

[0128] (2-2) A case where the steering instruction angle θd is equal to or larger than the steering angle threshold θa during the intermittent control (switching to the turning control from the intermittent control).

[0129] In this manner, the propulsion system in the present embodiment includes: the drive source 12; the propulsor 14, which generates thrust in accordance with the dynamic power transmitted from the drive source 12; at least one propulsion device 3, which is provided on the hull 2; and the controller 8, which controls the thrust of the propulsion device 3. The controller 8 is capable of conducting the intermittent control of intermittently changing the thrust of at least one propulsion device 3, based on a condition for changing the boat speed V, and the turning control of generating the thrust in the propulsion device 3 toward the course of the hull 2 based on the instruction value to be input into the steering angle inputter 4, when the steering angle inputter 4 is operated during the intermittent control.

[0130] According to this constitution, by switching to the turning control from the intermittent control during the intermittent operation mode, the thrust of the propulsion device 3 is controlled toward the course of the hull 2, based on the instruction value to be input into the steering angle inputter 4 regardless of the condition for changing the boat speed V. Accordingly, cruising to make a turn in accordance with the instruction of the user is smoothly achievable, so that the response performance at the time of making a turn can be improved. As a result, in the present embodiment, it becomes possible to contribute to development of a sustainable transportation system.

[0131] In the propulsion system in the present embodiment, the controller 8 switches to the turning control from the intermittent control, when the steering instruction angle θd is equal to or larger than the steering angle threshold θa during the intermittent control in the intermittent operation mode.

[0132] According to this constitution, it becomes possible to continue the very slow speed cruising at the time of not making a turn or when the turning angle is small.

[0133] In the propulsion system in the present embodiment, the controller 8 continues the intermittent control, when the steering instruction angle θd is smaller than the steering angle threshold θa during the intermittent control in the intermittent operation mode.

[0134] According to this constitution, it becomes possible to continue the very slow speed cruising at the time of not making a turn or when the turning angle is small.

[0135] In the propulsion system in the present embodiment, during the intermittent control in the intermittent operation mode, the controller 8 switches to the turning control from the intermittent control, when the state in which the steering instruction angle θd is equal to or larger than the steering angle threshold θa is continuing for equal to or longer than the first predetermined time T1.

[0136] According to this constitution, an occurrence of the hunting between the intermittent control and the turning control can be suppressed, so that a sense of discomfort given to the user can be suppressed.

[0137] In the propulsion system in the present embodiment, during the turning control in the intermittent operation mode, the controller 8 switches to the intermittent control from the turning control, when the steering instruction angle θd is smaller than the steering angle threshold θa and the state in which the steering instruction angle θd is smaller than the steering angle threshold θa is continuing for equal to or longer than the second predetermined time T2.

[0138] According to this constitution, an occurrence of the hunting between the intermittent control and the turning control can be suppressed, so that a sense of discomfort given to the user can be suppressed.

[0139] In the propulsion system in the present embodiment, the second predetermined time T2 is set to be longer than the first predetermined time T1.

[0140] According to this constitution, by ensuring the second predetermined time T2 to be long, the delay of the turning performance can be compensated in the latter half of the turning, and the turning amount in accordance with an intention of the user can be ensured even during the intermittent operation mode. On the other hand, by shortening the first predetermined time T1, it is possible to improve the response performance in the former half of the turning.

[0141] In the propulsion system in the present embodiment, the steering angle threshold θa includes the right steering angle threshold θar for changing the course of the hull 2 to the right with respect to the straight advancing direction, and the left steering angle threshold θal for changing the course of the hull 2 to the left with respect to the straight advancing direction.

[0142] According to this constitution, it becomes possible to determine whether to continue the intermittent control or to conduct the turning control at each time of turning to the right and turning to the left during the intermittent operation mode.

[0143] In the propulsion system in the present embodiment, the absolute values of the right steering angle threshold θar and the left steering angle threshold θal are set to be equal to each other.

[0144] According to this constitution, since it becomes possible to unify the operation feeling at the time of turning to the right and at the time of turning to the left, so that a sense of discomfort given to the user can be suppressed.

[0145] In the propulsion system in the present embodiment, the controller 8 is capable of performing the normal operation mode of controlling the dynamic power of the drive source 12, based on the requested thrust Sd, in a case where the requested shift position is the forward position F and the output of the drive source 12 based on the requested thrust Sd is larger than the minimum output value, and the intermittent operation mode of conducting at least the intermittent control in a case where the requested shift position is the forward position F and the output of the drive source 12 based on the requested thrust Sd is the minimum output value of the drive source 12. In the intermittent control, the shift position is changed between the forward position F and the neutral position N, while the output of the drive source 12 is kept constant.

[0146] According to this constitution, in the intermittent control in the intermittent operation mode, for example, it becomes possible to cruise the boat 1 at the boat speed V, which is achievable with equal to or smaller thrust to be output at the minimum output value of the drive source 12, without the user manually switching the shift position. Accordingly, convenience can be improved.

[0147] In the propulsion system in the present embodiment, in the intermittent operation mode, the controller 8 sets the shift position to the neutral position N from the forward position F, when the boat speed V is equal to or higher than the first speed threshold V1.

[0148] According to this constitution, since the thrust of the propulsion device 3 becomes zero when the boat speed V is equal to or higher than the first speed threshold V1, an increase in the boat speed V caused by the thrust of the propulsion device 3 is suppressed. As a result, it becomes possible to cruise the boat 1 at a very slow speed of the boat speed V, which is equal to or lower than the first speed threshold V1.

[0149] In the propulsion system in the present embodiment, in the intermittent operation mode, the controller 8 sets the shift position to the forward position from the neutral position, when the boat speed V is equal to or lower than the second speed threshold V2.

[0150] According to this constitution, it becomes possible to increase the boat speed V by applying the thrust of the propulsion device 3. As a result, it becomes possible to cruise the boat 1 at a very slow speed of the boat speed V, which is equal to or higher than the second speed threshold V2.

[0151] Furthermore, by conducting the intermittent control using the boat speed V itself as the condition for changing the boat speed V as described in the present embodiment, it becomes possible to maintain the boat speed V within a desired very slow speed region with high accuracy, as compared with a case where the intermittent control is conducted, based on time, for example.

[0152] In the propulsion system in the present embodiment, the instruction value is an operation amount on the steering angle inputter 4.

[0153] According to this constitution, smooth turning is enabled regardless of the situation at the time of making a turn.Modifications of First Embodiment

[0154] In the above-described first embodiment, in the intermittent operation mode, when the steering instruction angle θd is equal to or larger than the steering angle threshold θa, the intermittent control is switched to the turning control. However, the present disclosure is not limited to this constitution. When the absolute value of the steering instruction angle θd is larger than 0 degrees, the intermittent control may be switched to the turning control.

[0155] In the above-described first embodiment, in the intermittent operation mode, the constitution has been described in which the intermittent control is switched to the turning control from the intermittent control, in a case where the steering instruction angle θd, which is equal to or larger than the steering angle threshold θa, is continuing for equal to or longer than the first predetermined time T1. However, the present disclosure is not limited to this constitution. When the steering instruction angle θd is equal to or larger than the steering angle threshold θa, the intermittent control may be promptly switched to the turning control.

[0156] In the above-described embodiment, the constitution has been described in which the turning control is switched to the intermittent control from the turning control, in a case where after the steering instruction angle θd returns to be smaller than the steering angle threshold θa in the intermittent operation mode and the steering instruction angle θd, which is smaller than the steering angle threshold θa, is continuing for equal to or longer than the second predetermined time T2. However, the present disclosure is not limited to this constitution. The turning control may be promptly switched to the intermittent control, when the steering instruction angle θd returns to be smaller than the steering angle threshold θa.

[0157] In the above-described embodiment, the constitution in which the second predetermined time T2 is set to be longer than the first predetermined time T1 has been described. However, the present disclosure is not limited to this constitution. The second predetermined time T2 may be equal to or shorter than the first predetermined time T1.

[0158] In the above-described embodiment, the constitution in which the right steering angle threshold θar and the left steering angle threshold θal are included as the steering angle threshold θa has been described. However, the present disclosure is not limited to this constitution.

[0159] In the above-described first embodiment, as the determination of switching between the intermittent operation mode and the normal operation mode, the constitution has been described in which the maximum value (the switching threshold Va) of the boat speed V, which is achievable when the requested thrust is equal to or smaller than the thrust to be output at the minimum output value of the drive source 12. However, the present disclosure is not limited to this constitution. The switching threshold Va can be set with any value.

[0160] In the above-described first embodiment, the constitution has been described in which the shift position is switched, based on the boat speed V, from a start timing of the intermittent operation mode (the intermittent control). However, the present disclosure is not limited to this constitution. At the start timing of the intermittent operation mode (the intermittent control), after the shift position is continuously located at the forward position F for a predetermined period of time, the shift position may be switched, based on the boat speed V.

[0161] According to this constitution, it becomes possible to suppress a decrease amount of the boat speed V at the time of changing to the intermittent operation mode from the normal operation mode. Accordingly, a sense of discomfort given to the user can be suppressed.Second Embodiment

[0162] In the first embodiment, the boat speed V itself is used as the condition for changing the boat speed V. On the other hand, a second embodiment is different from the above-described first embodiment in that a period of time (a shift switching cycle) is used as the condition for changing the boat speed V in the intermittent operation mode (the intermittent control). FIG. 11 is a timing chart showing the operation of the propulsion system.

[0163] As indicated by time t11 to time t13 in FIG. 11, the intermittent control in the present embodiment switches the shift position between the forward position F and the neutral position N, based on a shift switching cycle Ts. The shift switching cycle Ts denotes a period of time while a forward setting time Tfl and a neutral setting time Tnl are respectively performed once. In the present embodiment, during the intermittent control, the shift position is switched between the forward position F and the neutral position N by repeating the shift switching cycle Ts. Note that the shift switching cycle Ts is set to be longer than the control cycle and the first predetermined time T1.

[0164] FIG. 12 is a flowchart showing a shift switching operation during the intermittent operation mode in the propulsion system.

[0165] As illustrated in FIGS. 11 and 12, in step S51, whether the current shift position is the forward position F is determined, based on a detection result of the position sensor 32 (for example, time t11 in FIG. 11).

[0166] In a case where a determination result of step S51 is “YES”, it is determined that the current shift position is the forward position F, and processing proceeds to step S52.

[0167] In step S52, the controller 8 determines whether duration of the forward position F (forward duration Tf) is equal to or longer than the forward setting time Tfl. Note that the forward duration Tf is measured by a timer provided in the controller 8.

[0168] In a case where the determination result of step S52 is “YES” (Tf≥Tfl), the processing proceeds to step S53.

[0169] In step S53, the controller 8 changes the shift position of the propulsion device 3 to the neutral position N (for example, time t12 in FIG. 11). Accordingly, the thrust of the propulsion device 3 becomes zero. That is, an increase in the boat speed V caused by the thrust of the propulsion device 3 is suppressed.

[0170] In a case where the determination result of step S53 is “NO” (Tf<Tfl), the processing proceeds to step S54.

[0171] In step S54, the controller 8 continues the shift position of the propulsion device 3 at the forward position F (for example, from time t11 to time t12 in FIG. 11). Accordingly, the thrust of the propulsion device 3 is continuously applied, and the boat speed V increases due to the thrust of the propulsion device 3.

[0172] In a case where the determination result in step S51 is “NO”, the current shift position is determined to be the neutral position N, and the processing proceeds to step S55.

[0173] In step S55, the controller 8 determines whether the duration of the neutral position N (neutral duration Tn) is equal to or longer than the neutral setting time Tnl. Note that the neutral duration Tn is measured by a timer provided in the controller 8. In the present embodiment, the neutral setting time Tnl is longer than the forward setting time Tfl. However, the neutral setting time Tnl may be equal to or shorter than the forward setting time Tfl.

[0174] In a case where the determination result of step S55 is “YES” (Tn≥Tnl), the processing proceeds to step S56.

[0175] In step S56, the controller 8 changes the shift position of the propulsion device 3 to the forward position F (for example, time t13 in FIG. 11). Accordingly, the thrust of the propulsion device 3 is applied, and thus the boat speed V increases (for example, times t13 to t14 in FIG. 11).

[0176] In a case where the determination result of step S55 is “NO” (Tn<Tnl), the processing proceeds to step S57.

[0177] In step S57, the controller 8 maintains the shift position of the propulsion device 3 at the neutral position N (for example, time t12 to t13 in FIG. 11). Accordingly, an increase in the boat speed V caused by the thrust of the propulsion device 3 is suppressed.

[0178] In the intermittent operation mode, by repeating the routine of the above-described intermittent control, it becomes possible to cruise the boat 1 while maintaining the boat speed V within the very slow speed region.

[0179] FIG. 13 is a flowchart showing the operation during the intermittent operation mode.

[0180] As illustrated in FIGS. 11 and 13, in step S61, the controller 8 determines whether the steering instruction angle θd is equal to or larger than the steering angle threshold θa.

[0181] In a case where the determination result of step S61 is “NO”, processing proceeds to Step s62 (θ<θa).

[0182] In step S62, the controller 8 sets “0” to the steering flag.

[0183] In a case where the determination result of step S61 is “YES”, the processing proceeds to step S63 (θ≥θa).

[0184] In step S63, the controller 8 sets “1” to the steering flag, and the processing proceeds to step S64.

[0185] In step S64, the controller 8 stops the intermittent control. In this situation, the controller 8 stores the position in the shift switching cycle at the time of stopping the intermittent control. In the example of FIG. 11, at time t15, in the shift switching cycle, a state in which the steering instruction angle θd is equal to or larger than the steering angle threshold θa before the neutral duration Tn reaches the neutral setting time Tnf is indicated. Therefore, the controller 8 stops the intermittent control partway through the neutral setting time Tnl.

[0186] In step S65, the controller 8 sets the shift position to the forward position F. Accordingly, the boat 1 cruises while increasing the boat speed V toward a desired course (the turning control).

[0187] In step S66, the controller 8 determines whether a state in which the steering flag is “0” is continuing for equal to or longer than a third predetermined time T3. The third predetermined time T3 is set to be longer than the control period and to be shorter than the shift switching cycle Ts. In the present embodiment, the third predetermined time T3 is preferably set to be shorter than at least the neutral setting time Tnl.

[0188] In a case where the determination result of step S66 is “NO”, the processing proceeds to step S67.

[0189] In step S67, the shift position is set to the forward position F. That is, in step S67, soon after the steering instruction angle θd returns to be smaller than the steering angle threshold θa, the shift position is continuously located at the forward position F (continuously conducting the turning control).

[0190] In a case where the determination result of step S66 is “YES”, the processing proceeds to step S68.

[0191] In step S68, the controller 8 determines whether the shift switching cycle Ts (the intermittent control) is temporarily stopped.

[0192] In a case where the determination result of step S68 is “YES”, the controller 8 calls, in step S69, the shift switching cycle Ts, which is stopped in step S64. The case where the determination result in step S69 is “YES” means, for example, a case where after the turning control returns to the intermittent control, a first cycle of the intermittent control is conducted, based on the shift switching cycle Ts. In this case, the intermittent control is restarted, based on the shift switching cycle Ts (a first cycle of the shift switching cycle Ts) at a stopped timing in accordance with the change to the turning control. Therefore, in step S69, information at the stopped timing about a previous time of the intermittent control is called.

[0193] Then, in step S70, the controller 8 restarts the intermittent control from the stopped timing due to changing to the turning control, in the shift switching cycle Ts (for example, time t16 in FIG. 11). That is, in the illustrated example, in a previous time of the intermittent control, the intermittent control is stopped partway through the neutral setting time Tnl. Therefore, in step S70, the intermittent control is restarted from the neutral position N, as the stopped timing in the previous time of the intermittent control. In this case, after an incomplete portion in the neutral setting time Tnl is completed, the shift position is switched to the forward position F (for example, time t17 in FIG. 11).

[0194] In a case where the determination result of step S68 is “NO”, the processing proceeds to step S71. The case where the determination result in step S68 is “NO” includes, for example, a case where after the turning control returns to the intermittent control, the first cycle of the shift switching cycle Ts elapses (a case where second and subsequent cycles of the intermittent control are conducted, based on the shift switching cycle Ts).

[0195] In step S71, the intermittent control is continued. That is, in step S71, since there is no incomplete shift switching cycle, the intermittent control illustrated in FIG. 6 continues.

[0196] In the propulsion system in the present embodiment, by switching the shift position between the forward position F and the neutral position N, based on the shift switching cycle in the intermittent operation mode, the controller 8 conducts the intermittent control of the thrust.

[0197] According to this constitution, by switching the shift position, based on the shift switching cycle that has been set beforehand, it becomes possible to simplify the control, as compared with a case of switching the shift position, based on the boat speed V.

[0198] In the propulsion system in the present embodiment, when changing to the intermittent control from the turning control, the controller 8 restarts the intermittent control from the stopped timing due to changing to the turning control in the shift switching cycle Ts in the previous time of the intermittent control.

[0199] According to this constitution, when returning to the intermittent control from the turning control, the intermittent control is restarted from a stopped state of a previous time, so that a sense of discomfort given to the user can be suppressed.Modification of Second Embodiment

[0200] In the above-described second embodiment, the constitution has been described in which a ratio occupied by the neutral setting time Tnl is larger than a ratio occupied by the forward setting time Tfl in the shift switching cycle. However, the present disclosure is not limited to this constitution. In one shift switching cycle, the lengths, ratios, and the like of the neutral setting time Tnl and the forward setting time Tfl can be appropriately changed.

[0201] In the above-described second embodiment, the constitution has been described in which the shift position is switched, based on one type of the shift switching cycle Ts in the intermittent control. However, the present disclosure is not limited to this constitution. The controller 8 may conduct the intermittent control by selecting one shift switching cycle Ts from a plurality of types of shift switching cycles Ts. In the plurality of types of shift switching cycles Ts, it is sufficient if at least one of the forward setting time Tfl and the neutral setting time Tnl are different from each other in each shift switching cycle Ts. In this case, the length of each shift switching cycle Ts itself may be equal or different.

[0202] In the constitution including the plurality of types of shift switching cycles Ts, the controller 8 is capable of selecting any one of the plurality of types of shift switching cycles Ts, based on, for example, the requested thrust Sd, the sea condition, or the like. In this case, for example, in a case where the requested thrust Sd is high, the controller 8 preferably selects the shift switching cycle Ts in which the ratio occupied by the neutral setting time Tnl is smaller in the shift switching cycle Ts than that in a case where the requested thrust Sd is low. Accordingly, the boat speed V is easily adjusted in accordance with the requested thrust Sd.Third Embodiment

[0203] A third embodiment is different from the second embodiment in that when the turning control returns to the intermittent control, the intermittent control is restarted from the start point of the shift switching cycle Ts. FIG. 14 is a timing chart showing the operation of the propulsion system. FIG. 15 is a flowchart showing the operation during the intermittent operation mode in the propulsion system.

[0204] In the propulsion system in the third embodiment illustrated in FIG. 14, in step S75, the controller 8 determines whether the steering instruction angle θd is equal to or larger than the steering angle threshold θa.

[0205] In a case where a determination result of step S75 is “NO”, processing proceeds to step S76 (θ<θa).

[0206] In step S76, the controller 8 sets “0” to the steering flag.

[0207] In a case where the determination result of step S75 is “YES”, the processing proceeds to step S77 (θ≥θa).

[0208] In step S77, the controller 8 sets “1” to the steering flag, and the processing proceeds to step S78.

[0209] In step S78, the controller 8 resets the record of the shift switching cycle Ts, which is being performed (reset history=1).

[0210] In step S79, the controller 8 sets the shift position to the forward position F. That is, the boat 1 cruises while increasing the boat speed V toward a desired course (the turning control), accordingly. Note that at time t21 in FIG. 14, a state in which the shift position of the intermittent control is the forward position F is changed to the turning control is indicated. Therefore, the shift position is maintained at the forward position F in accordance with the change to the turning control from the intermittent control.

[0211] In step S80, the controller 8 determines whether the reset history is “1”.

[0212] In a case where a determination result of step S80 is “NO”, the processing proceeds to step S81.

[0213] In step S81, the intermittent control illustrated in FIG. 6 continues, based on the shift switching cycle Ts. Note that the case where the determination result in step S80 denotes “NO” means, for example, a case where after the turning control returns to the intermittent control, the first cycle of the shift switching cycle Ts elapses (a case where the second and subsequent cycles of the intermittent control are conducted, based on the shift switching cycle Ts).

[0214] In a case where the determination result of step S80 is “YES”, the processing proceeds to step S82.

[0215] In step S82, the controller 8 determines whether a state in which the steering flag is “0” is continuing for equal to or longer than a third predetermined time T3.

[0216] In a case where the determination result of step S82 is “NO”, the processing proceeds to step S83.

[0217] In step S83, the controller 8 sets (maintains) the shift position to the forward position F.

[0218] In a case where a determination result of step S82 is “YES”, the processing proceeds to step S84.

[0219] In step S84, the controller 8 sets “0” to the reset history. That is, after the turning control, the controller 8 resets the record of the previous time of the intermittent control when returning to the intermittent control.

[0220] In step S85, the controller 8 restarts the intermittent control from the start point of the shift switching cycle (for example, time t22 in FIG. 14). In the present embodiment, the shift position at the start timing of the shift switching cycle Ts is set to the neutral position N.

[0221] In the propulsion system in the present embodiment, when returning to the intermittent control from the turning control, the controller 8 restarts the intermittent control from the start point of the shift switching cycle Ts.

[0222] According to this constitution, it is not necessary to store stopped information in the intermittent control, so that the control can be simplified. In addition, for example, by setting the shift position at the start timing of the shift switching cycle Ts to the neutral position N, it becomes possible to prevent an excessive increase in the boat speed V after the shift position is switched to the turning control from the intermittent control and then returns to the intermittent control again, in a case where the shift position is the forward position F.Modification of Third Embodiment

[0223] Also in the third embodiment, any shift switching cycle may be selected from a plurality of shift switching cycles in accordance with the requested thrust.

[0224] In the above-described third embodiment, the case where the start point of the shift switching cycle is the neutral position N has been described. However, the present disclosure is not limited to this constitution. The start point of the shift switching cycle may be the forward position F.Fourth Embodiment

[0225] FIG. 16 is a flowchart showing an operation method of the propulsion system according to a fourth embodiment. In the above-described embodiments, the constitution has been described in which each propulsion device 3 operates in synchronization in a case where a plurality of propulsion devices 3 are mounted. However, the present disclosure is not limited to this constitution. The fourth embodiment is different from the above-described embodiments in that operation timings of the plurality of propulsion devices 3 are made different from each other in the intermittent control, for example.

[0226] In the propulsion system in the present embodiment, out of the right propulsion device 3a and the left propulsion device 3b illustrated in FIG. 1, the propulsion device 3 (for example, the right propulsion device 3a) on one side belongs to a first propulsion device group 3, and the propulsion device 3 (for example, the left propulsion device 3b) on the other side belongs to a second propulsion device group 3. Hereinafter, for example, in the intermittent control illustrated in FIG. 5, a case where the shift position of the propulsion device 3 is switched to the forward position F from the neutral position N like step S16 will be described as an example.

[0227] As illustrated in FIG. 16, in step S90, the controller 8 determines whether change of the shift position (for example, change to the forward position F from the neutral position N) has been completed for the first propulsion device group 3.

[0228] In a case where a determination result of step S90 is “NO”, processing proceeds to step S91. In step S91, the controller 8 changes the shift position of the first propulsion device group 3.

[0229] In a case where the determination result of step S90 is “YES”, the processing proceeds to step S92. In step S92, the controller 8 determines whether the change of the shift position (for example, the change to the forward position F from the neutral position N) has been completed for the second propulsion device group 3.

[0230] In a case where the determination result of step S92 is “NO”, the processing proceeds to step S93. In step S93, the controller 8 changes the shift position of the second propulsion device group 3.

[0231] In a case where the determination result of step S92 is “YES”, it is determined that the change of the shift positions of all the propulsion devices 3 has been completed, and this routine ends.

[0232] In the propulsion system in the present embodiment, the controller 8 makes switching timings of the shift positions of the right propulsion device 3a and the left propulsion device 3b different from each other in the intermittent operation mode.

[0233] According to this constitution, vibrations or the like caused by the shift shock can be suppressed, as compared with a case where the shift positions are simultaneously switched for the respective propulsion devices 3. Accordingly, a sense of discomfort given to the user can be suppressed.Fifth Embodiment

[0234] FIG. 17 is a plan view of a boat 1 according to a fifth embodiment. In the above-described embodiments, the constitution has been described in which the absolute values of the right steering angle threshold θar and the left steering angle threshold θal are equal to each other. However, the present disclosure is not limited to this constitution. The absolute values of the right steering angle threshold θar and the left steering angle threshold θal may be different from each other.

[0235] In the boat 1 illustrated in FIG. 17, the controller 8 includes the right steering angle threshold θar and the left steering angle threshold θal respectively for the right propulsion device 3a and the left propulsion device 3b. For the right propulsion device 3a, the absolute value of the left steering angle threshold θal is set to be smaller than the absolute value of the right steering angle threshold θar. For the left propulsion device 3b, the absolute value of the right steering angle threshold θar is set to be smaller than the absolute value of the left steering angle threshold θal. In this case, the absolute value of the left steering angle threshold θal of the right propulsion device 3a is set to be smaller than the absolute value of the left steering angle threshold θal of the left propulsion device 3b. In addition, the absolute value of the right steering angle threshold θar of the left propulsion device 3b is set to be smaller than the absolute value of the right steering angle threshold θar of the right propulsion device 3a. That is, in the present embodiment, when the boat 1 makes a turn, the steering angle threshold θa of the propulsion device 3, which is located on an outer side, is set to be smaller than the steering angle threshold θa of the propulsion device 3, which is located on the inner side.

[0236] FIG. 18 is a plan view of the boat 1 at the time of turning to the right.

[0237] In the present embodiment, in the routine of step S25, whether the steering instruction angle θd is equal to or larger than the steering angle threshold θa is determined for each of the propulsion devices 3a and 3b. When turning to the right as illustrated in FIG. 18, the controller 8 determines whether the steering instruction angle θd is equal to or larger than the steering angle threshold θa in each of the propulsion devices 3a and 3b. In this case, the absolute value of the right steering angle threshold θar of the left propulsion device 3b is set to be smaller than the absolute value of the right steering angle threshold θar of the right propulsion device 3a. Therefore, the left propulsion device 3b is switched to the turning control from the intermittent control at a timing earlier than a timing of the right propulsion device 3a (a timing when the steering instruction angle θd is small).

[0238] FIG. 19 is a plan view of the boat 1 at the time of turning to the left.

[0239] When turning to the left as illustrated in FIG. 19, the controller 8 determines whether the steering instruction angle θd is equal to or larger than the left steering angle threshold θal in each of the propulsion devices 3a and 3b. In this case, the absolute value of the left steering angle threshold θal of the right propulsion device 3a is set to be smaller than the absolute value of the left steering angle threshold θal of the left propulsion device 3b. Therefore, the right propulsion device 3a is switched to the turning control from the intermittent control at a timing earlier than a timing of the left propulsion device 3b (a timing when the steering instruction angle θd is small).

[0240] In this manner, in the present embodiment, when the boat 1 makes a turn, the steering angle threshold θa of the propulsion device 3, which is located on an outer side, is set to be smaller than the steering angle threshold θa of the propulsion device 3, which is located on an inner side.

[0241] According to this constitution, when the boat 1 makes a turn, the propulsion device 3, which is located on the outer side, is switched to the turning control from the intermittent control earlier, so that the turning performance can be improved. In the present embodiment, the constitution has been described in which the absolute value of the right steering angle threshold θar and the absolute value of the left steering angle threshold θal are different from each other in accordance with the turning direction. However, the present disclosure is not limited to this constitution. Also, when changing the settings between the propulsion devices 3a and 3b in accordance with the rotation direction or trim angle of the propeller 22, the absolute value of the right steering angle threshold θar and the absolute value of the left steering angle threshold θal may be different from each other.Sixth Embodiment

[0242] FIG. 20 is a plan view of a boat 1 according to a sixth embodiment. A sixth embodiment is different from the above-described embodiments in that three or more propulsion devices 3 are provided.

[0243] The boat 1 illustrated in FIG. 20 includes four propulsion devices 103a to 103d. The four propulsion devices 103a to 103d include a right outer propulsion device 103a, a left outer propulsion device 103b, a right inner propulsion device 103c, and a left inner propulsion device 103d. The right outer propulsion device 103a is provided at a right end portion of the stern. The left outer propulsion device 103b is provided at a left end portion of the stern. The right inner propulsion device 103c is provided between the right outer propulsion device 103a and the left outer propulsion device 103b on the right side with respect to the center line CL. The left inner propulsion device 103d is provided between the right outer propulsion device 103a and the left outer propulsion device 103b on the left side with respect to the center line CL.

[0244] Like the present embodiment, in a case where three or more propulsion devices 103a to 103d are provided, only some of the propulsion devices 103a to 103d may be constituted to conduct the intermittent control in the intermittent operation mode.

[0245] In this case, for example, for the outer propulsion devices 103a and 103b, the shift positions may be switched between the forward position F and the neutral position N based on the intermittent control, whereas the inner propulsion devices 103c and 103d may fix the shift positions to the neutral position N. Accordingly, by generating thrust in the outer propulsion devices 103a and 103b, it becomes possible to improve the turning performance when the boat 1 makes a turn.

[0246] In addition, for the inner propulsion devices 103c and 103d, the shift positions may be switched between the forward position F and the neutral position N based on the intermittent control, whereas the outer propulsion devices 103a and 103b may fix the shift positions to the forward position F.[Other Modifications]

[0247] Heretofore, although preferred examples in the present disclosure have been described, the present disclosure is not limited to these examples. Additions, omissions, substitutions, and other changes of the constitution can be made without departing from the gist in the present disclosure. The present disclosure is not limited by the foregoing description, and is limited only by the appended claims.

[0248] In addition, as the type of the hull 2, the present disclosure may be applied to various moving bodies on water such as a V shape hull, a pontoon boat, a center console, a runabout, a fishing boat, and a jet ski.

[0249] In the above-described embodiments, the case where the drive source 12 is an internal combustion engine has been described. However, the present disclosure is not limited to this constitution. The drive source 12 may be an electric motor or the like. In a case of the electric motor, the motor rotation speed, torque, and the like correspond to “thrust”. In this case, the neutral position N is obtained by setting the motor rotation speed to zero.

[0250] When automatic driving or driving assistance (for example, cruise control as autopilot or constant-speed driving) is performed, a computer may be constituted to calculate an instruction value and set a target speed or the like, instead of the user (boat operator) inputting the “requested thrust Sd”.

[0251] In the above-described embodiments, the constitution has been described in which the intermittent control is conducted by switching the shift position between the forward position F and the neutral position N. However, the present disclosure is not limited to this constitution. The intermittent control may be conducted by switching between the forward position F and the reverse position R.

[0252] In the above-described embodiments, the intermittent operation mode has been described by using the forward movement of the boat 1 as an example. However, the present disclosure is not limited to this constitution. The intermittent operation mode may be conducted when the boat 1 moves rearward. In this case, as the intermittent control, the shift position may be switched between the reverse position R and the neutral position N, or the shift position may be switched between the reverse position R and the forward position F.

[0253] In the above-described embodiments, the constitution has been described in which the very slow speed cruising is enabled by switching the shift position in the intermittent operation mode. However, the present disclosure is not limited to this constitution. The intermittent operation mode may be achieved by fluctuation of the thrust within the identical shift position (the forward position F at the time of moving forward and the reverse position R at the time of moving rearward) based on the course of the boat 1.

[0254] In the above-described embodiments, the constitution of the boat 1 has been described by giving the case where the plurality of propulsion devices 3 are provided as an example. However, the present disclosure is not limited to this constitution. It is sufficient if at least one propulsion device is provided. In this case, a singular number of the propulsion device 3 may be provided.

[0255] In the above-described embodiments, the constitution has been described in which the valid state and the invalid state of the intermittent operation mode are switched by the operation on the operation unit 7. However, the present disclosure is not limited to this constitution. The intermittent operation mode may be always valid.

[0256] In the above-described embodiments, the constitution has been described in which the intermittent control and the turning control are switched, based on the steering instruction angle θd, while the intermittent operation mode is maintained. However, the present disclosure is not limited to this constitution. In the intermittent operation mode, it is sufficient if at least the intermittent control can be conducted. That is, when the intermittent control is changed to the turning control, the intermittent operation mode may be changed to the normal operation mode. In this case, the intermittent operation mode and the normal operation mode are switched, based on the steering instruction angle θd.

[0257] In the above-described embodiments, the constitution has been described in which the steering instruction angle θd is calculated, based on the operation amount on the steering angle inputter 4. However, the present disclosure is not limited to this constitution. The steering instruction angle θd may be constituted to be calculated, based on the operation amount on the steering angle inputter 4 per unit time. According to this constitution, the intermittent control is switched to the turning control, only when the output of the propulsion device 3 is necessary, such as at the time of suddenly making a turn. This makes it possible to improve fuel efficiency.

[0258] In addition, it is possible to appropriately replace any constituent element in the above-described embodiments with a known constituent element without departing from the gist in the present disclosure, and the above-described modifications may be appropriately combined together.

[0259] While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary examples of the invention and are not to be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the scope of the present invention. Accordingly, the invention is not to be considered as being limited by the foregoing description, and is only limited by the scope of the appended claims.REFERENCE SIGNS LIST1 Boat

[0261] 2 Hull

[0262] 3 Propulsion device

[0263] 3a Right propulsion device (propulsion device)

[0264] 3b Left propulsion device (propulsion device)

[0265] 4 Steering angle inputter

[0266] 5 Thrust inputter

[0267] 8 Controller

[0268] 12 Drive source

[0269] 14 Propulsor

[0270] 103a Right outer propulsion device

[0271] 103b Left outer propulsion device

[0272] 103c Right inner propulsion device

[0273] 103d Left inner propulsion device

[0274] Sd Requested thrust

[0275] Ts Shift switching cycle

[0276] V Boat speed

[0277] V1 First speed threshold

[0278] V2 Second speed threshold

[0279] θa Steering angle threshold

[0280] θal Left steering angle threshold

[0281] θar Right steering angle threshold

[0282] θd Steering instruction angle

Examples

first embodiment

Modifications of First Embodiment

[0154]In the above-described first embodiment, in the intermittent operation mode, when the steering instruction angle θd is equal to or larger than the steering angle threshold θa, the intermittent control is switched to the turning control. However, the present disclosure is not limited to this constitution. When the absolute value of the steering instruction angle θd is larger than 0 degrees, the intermittent control may be switched to the turning control.

[0155]In the above-described first embodiment, in the intermittent operation mode, the constitution has been described in which the intermittent control is switched to the turning control from the intermittent control, in a case where the steering instruction angle θd, which is equal to or larger than the steering angle threshold θa, is continuing for equal to or longer than the first predetermined time T1. However, the present disclosure is not limited to this constitution. When the steering ins...

second embodiment

Modification of Second Embodiment

[0200]In the above-described second embodiment, the constitution has been described in which a ratio occupied by the neutral setting time Tnl is larger than a ratio occupied by the forward setting time Tfl in the shift switching cycle. However, the present disclosure is not limited to this constitution. In one shift switching cycle, the lengths, ratios, and the like of the neutral setting time Tnl and the forward setting time Tfl can be appropriately changed.

[0201]In the above-described second embodiment, the constitution has been described in which the shift position is switched, based on one type of the shift switching cycle Ts in the intermittent control. However, the present disclosure is not limited to this constitution. The controller 8 may conduct the intermittent control by selecting one shift switching cycle Ts from a plurality of types of shift switching cycles Ts. In the plurality of types of shift switching cycles Ts, it is sufficient if ...

third embodiment

Modification of Third Embodiment

[0223]Also in the third embodiment, any shift switching cycle may be selected from a plurality of shift switching cycles in accordance with the requested thrust.

[0224]In the above-described third embodiment, the case where the start point of the shift switching cycle is the neutral position N has been described. However, the present disclosure is not limited to this constitution. The start point of the shift switching cycle may be the forward position F.

Claims

1. A propulsion system of a boat, the propulsion system comprising:at least one propulsion device provided on a hull, the at least one propulsion device including a drive source and a propulsor that generates thrust with dynamic power transmitted from the drive source; anda controller including at least a processor and a memory, the controller being configured to control the thrust of the propulsion device, whereinthe controller is capable of conductingintermittent control of intermittently changing the thrust of the at least one propulsion device, based on a condition for changing a boat speed, andturning control of causing the propulsion device to generate the thrust toward a course of the hull, based on an instruction value to be input into a steering angle inputter, when the steering angle inputter is operated during the intermittent control.

2. The propulsion system of the boat according to claim 1, wherein during the intermittent control, the controller switches to the turning control from the intermittent control, in a case where a steering instruction angle to the propulsion device based on the instruction value is equal to or larger than a steering angle threshold.

3. The propulsion system of the boat according to claim 1, wherein during the intermittent control, the controller continues the intermittent control, in a case where a steering instruction angle to the propulsion device based on the instruction value is smaller than the steering angle threshold.

4. The propulsion system of the boat according to claim 2, wherein during the intermittent control, the controller switches to the turning control from the intermittent control, in a case where a state in which the steering instruction angle is equal to or larger than the steering angle threshold continues for a time equal to or longer than a first predetermined time.

5. The propulsion system of the boat according to claim 2, wherein during the turning control, the controller switches to the intermittent control from the turning control, in a case where a state in which the steering instruction angle is smaller than the steering angle threshold continues for a time equal to or longer than a second predetermined time.

6. The propulsion system of the boat according to claim 2, wherein during the intermittent control, the controller switches to the turning control from the intermittent control, in a case where a state in which the steering instruction angle is equal to or larger than the steering angle threshold continues for a time equal to or longer than a first predetermined time,during the turning control, the controller switches to the intermittent control from the turning control, in a case where a state in which the steering instruction angle is smaller than the steering angle threshold continues for a time equal to or longer than a second predetermined time, andthe second predetermined time is set to be longer than the first predetermined time.

7. The propulsion system of the boat according to claim 2, whereinthe steering angle threshold includes:a right steering angle threshold for changing the course of the hull to a right side with respect to a straight advancing direction; anda left steering angle threshold for changing the course of the hull to a left side with respect to the straight advancing direction.

8. The propulsion system of the boat according to claim 7, wherein absolute values of the right steering angle threshold and the left steering angle threshold are set to be equal to each other.

9. The propulsion system of the boat according to claim 1, whereinthe controller controls a shift position of the propulsion device, based on a requested shift position that has been input into a thrust inputter, and also controls the dynamic power of the drive source, based on requested thrust that has been input into the thrust inputter,the controller is capable of conducting:a normal operation mode of controlling the dynamic power of the drive source, based on the requested thrust, in a case where the requested shift position is a forward position and the dynamic power of the drive source based on the requested thrust is other than being larger than a minimum output value; andan intermittent operation mode of conducting at least the intermittent control, in a case where the requested shift position is the forward position and the dynamic power of the drive source based on the requested thrust is a minimum output value of the drive source, andthe intermittent control changes the shift position between the forward position and a neutral position in a state in which the dynamic power of the drive source is kept constant.

10. The propulsion system of the boat according to claim 9, wherein the controller sets the shift position to the forward position at a start timing of the intermittent control.

11. The propulsion system of the boat according to claim 9, whereinthe condition for changing the boat speed is the boat speed, andduring the intermittent control, the controller sets the shift position to the neutral position from the forward position, in a case where the boat speed is equal to or higher than a first speed threshold.

12. The propulsion system of the boat according to claim 11, wherein during the intermittent control, the controller sets the shift position to the forward position from the neutral position, in a case where the boat speed is equal to or lower than a second speed threshold, the second speed threshold being smaller than the first speed threshold.

13. The propulsion system of the boat according to claim 9, whereinthe condition for changing the boat speed is at least one type of shift switching cycle that has been set in combination of a forward setting time while the forward position continues and a neutral setting time while the neutral position continues, andduring the intermittent control, the controller switches the shift position between the forward position and the neutral position, based on the shift switching cycle.

14. The propulsion system of the boat according to claim 13, whereinduring the intermittent control, the controller switches to the turning control from the intermittent control, in a case where a steering instruction angle to the propulsion device based on the instruction value is equal to or larger than a steering angle threshold,during the intermittent control, the controller switches to the intermittent control from the turning control, in a case where the steering instruction angle is smaller than the steering angle threshold, andwhen changing to the intermittent control from the turning control, the controller restarts the intermittent control from a stopped timing due to changing to the turning control in the shift switching cycle of a previous time of the intermittent control.

15. The propulsion system of the boat according to claim 13, whereinduring the intermittent control, the controller switches to the turning control from the intermittent control, in a case where a steering instruction angle to the propulsion device based on the instruction value is equal to or larger than a steering angle threshold,during the intermittent control, the controller switches to the intermittent control from the turning control, in a case where the steering instruction angle is smaller than the steering angle threshold,the controller sets the shift position of a start timing of the shift switching cycle to the neutral position, andwhen changing to the intermittent control from the turning control, the controller conducts the intermittent control from the start timing of the shift switching cycle.

16. The propulsion system of the boat according to claim 13, whereina plurality of types of the shift switching cycles in which at least one of the neutral setting time and the forward setting time is different are provided, andthe controller conducts the intermittent control, based on one of the plurality of types of the shift switching cycles.

17. The propulsion system of the boat according to claim 9, whereinthe at least one propulsion device includes: a left propulsion device provided on a left side with respect to a center in a left-right direction of the hull; and a right propulsion device provided on a right side with respect to the center in the left-right direction, andthe controller makes switching timings of the shift positions of the left propulsion device and the right propulsion device different from each other in the intermittent control.

18. The propulsion system of the boat according to claim 9, whereinthe at least one propulsion device includes: a left propulsion device provided on a left side with respect to a center in a left-right direction of the hull; and a right propulsion device provided on a right side with respect to the center in the left-right direction,during the intermittent control, the controller switches to the turning control from the intermittent control, in a case where a steering instruction angle based on the instruction value is equal to or larger than a steering angle threshold,the steering angle threshold includes:a right steering angle threshold for changing the course of the hull to the right side with respect to a straight advancing direction; anda left steering angle threshold for changing the course of the hull to the left side with respect to the straight advancing direction,an absolute value of the right steering angle threshold of the left propulsion device is set to be smaller than an absolute value of the right steering angle threshold of the right propulsion device, andan absolute value of the left steering angle threshold of the right propulsion device is set to be smaller than an absolute value of the left steering angle threshold of the left propulsion device.

19. The propulsion system of the boat according to claim 1, whereinthe at least one propulsion device includes: outer propulsion devices provided at both end portions of the hull in a left-right direction; and at least one inner propulsion device provided between the outer propulsion devices, andthe controller causes any of the outer propulsion devices and the inner propulsion device to conduct the intermittent control.

20. The propulsion system of the boat according to claim 19, wherein the controller sets a shift position of the inner propulsion device to a neutral position, when conducting the intermittent control on the outer propulsion devices.

21. The propulsion system of the boat according to claim 19, wherein the controller sets a shift position of the outer propulsion devices to a forward position, when conducting the intermittent control on the inner propulsion device.

22. The propulsion system of the boat according to claim 1, wherein the instruction value is an operation amount on the steering angle inputter.

23. The propulsion system of the boat according to claim 1, wherein the instruction value is an operation amount on the steering angle inputter per unit time.

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