Propulsion system of boat

Abstract

A propulsion system of a boat, includes: a trim angle adjuster configured to adjust a trim angle of each of propulsion machines on both sides in a left-right direction; and a controller configured to control the trim angle adjuster, in which while conducting heel control, in a state in which the at least one propulsion machine has a trim angle further inclined rearward in a propulsion direction of a hull than a first trim angle reference value, and in a case where a preset first condition is satisfied, the controller causes the trim angle adjuster to adjust the trim angle of the propulsion machine so that the trim angle of the propulsion machine is the first trim angle reference value or so that the propulsion machine has the trim angle further inclined forward in the propulsion direction than the first trim angle reference value.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] Priority is claimed on Japanese Patent Application No. 2025-057494, filed Mar. 31, 2025, the content of which is incorporated herein by reference.BACKGROUND OF THE INVENTIONField of the Invention

[0002] The present invention relates to a propulsion system of a boat.Description of Related Art

[0003] Various techniques for automatically controlling a propulsion system of a boat have been conventionally proposed in order to improve stability, acceleration, a maximum speed, energy efficiency, and the like, in navigating the boat.

[0004] For example, Japanese Patent No. 5059392 discloses a constitution related to heel control of controlling a heel angle of a boat. In this constitution, in a case where it is determined that the boat is not in a turning state in accordance with the steering angle of the steering mechanism of the boat, the heel angle of the boat is increased in a direction corresponding to the steering angle of the steering mechanism by generating a difference between left lift force and right lift force of the boat.SUMMARY OF THE INVENTION

[0005] On the boat, by the way, not only the heel control but also another type of control may be conducted in accordance with a navigation state of the boat. For example, different types of control may be conducted when the boat is in a straight advancing state and when the boat is in a turning state. In addition, when the boat operator manually performs the operation, each part may be in a different state from the control that has been automatically conducted.

[0006] In this manner, in transitioning from the state of conducting the heel control to another state, there is a demand for smoothly transitioning the state so as not to impair stability, acceleration, a maximum speed, energy efficiency, or the like of the boat, and so as not to make the boat operator feel uneasy.

[0007] The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a propulsion system of a boat capable of smoothly transitioning a state so as not to impair stability, acceleration, a maximum speed, energy efficiency, or the like of the boat, and so as not to make a boat operator feel uneasy or the like, in transitioning from a state of conducting heel control to another state.

[0008] In order to solve the above problems, the present disclosure adopts the following aspects.

[0009] (1) A propulsion system of a boat according to one aspect of the present disclosure, includes: at least one propulsion machine including a drive source, and a propulsor configured to generate thrust with dynamic power transmitted from the drive source, the at least one propulsion machine being provided on each of both sides in a left-right direction with respect to a center of a hull; a trim angle adjuster configured to adjust a trim angle of each of the propulsion machines on the both sides in the left-right direction with respect to the hull; and a controller configured to control the trim angle adjuster, in which the controller is capable of conducting heel control of causing the trim angle adjuster to adjust the trim angle to a heel suppression angle set in accordance with an inclination in a roll direction of the hull to suppress the inclination in the roll direction of the hull, and while conducting the heel control, in a state in which the at least one propulsion machine has a trim angle further inclined rearward in a propulsion direction of the hull than a preset first trim angle reference value, and in a case where a preset first condition is satisfied, the controller causes the trim angle adjuster to adjust the trim angle of the propulsion machine so that the trim angle of the propulsion machine is the first trim angle reference value or so that the propulsion machine has the trim angle further inclined forward in the propulsion direction than the first trim angle reference value.

[0010] (2) The propulsion system of the boat according to the above aspect (1) may further include a steering angle detector configured to detect a steering angle around a steering shaft of the propulsion machine with respect to the hull in accordance with an external input, in which in a case where it is determined that the boat is in a turning state, based on a detection value of the steering angle detected by the steering angle detector, the controller may determine that the first condition is satisfied.

[0011] (3) In the propulsion system of the boat according to the above aspect (2), in the case where it is determined that the boat is in the turning state, the trim angle adjuster may adjust the trim angle of the propulsion machine so that the trim angles of the propulsion machines become the first trim angle reference value in all of the propulsion machine on the both sides in the left-right direction.

[0012] (4) The propulsion system of the boat according to one of the above aspects (1) to (3) may further include a trim angle operation unit configured to operate the trim angle adjuster in accordance with an external input, in which upon receipt of an operation input from the trim angle operation unit, the controller may determine that the first condition is satisfied.

[0013] (5) The propulsion system of the boat according to one of the above aspects (1) to (4) may further include an intermediate member provided between the hull and the propulsion machine, the intermediate member increasing a rearward inclination angle in the propulsion direction of the propulsion machine, in which the first trim angle reference value may be set, based on the trim angle of the propulsion machine in a state in which the propulsion machine is most inclined rearward in the propulsion direction in a case where the propulsion machine is provided on the hull without provision of the intermediate member.

[0014] (6) In the propulsion system of the boat according to the above aspect (5), in conducting the heel control, the controller may cause the trim angle adjuster to adjust the trim angle of the propulsion machine with a second trim angle reference value as a lower limit value, the second trim angle reference value being set, based on the trim angle of the propulsion machine in a case where the propulsion machine provided on the hull via the intermediate member is most inclined rearward in the propulsion direction.

[0015] (7) In the propulsion system of the boat according to the above aspect (2) or (3), in a case where it is determined that the boat is advancing straight, based on the detection value of the steering angle, the controller may enable conducting the heel control.

[0016] (8) The propulsion system of the boat according to the above aspect (7) may further include a heel angle detector configured to detect a heel angle serving as an inclination in a roll direction of the hull, in which in a case where the heel angle is equal to or larger than a preset heel angle reference value, the controller may conduct the heel control.

[0017] (9) In the propulsion system of the boat according to the above aspect (2) or (3), while conducting the heel control, in a case where it is determined that the boat is in the turning state, based on the detection value of the steering angle, the controller may stop conducting the heel control.

[0018] (10) The propulsion system of the boat according to one of the above aspects (1) to (9) may further include a trim angle operation unit configured to operate the trim angle adjuster in accordance with an external input, in which while conducting the heel control, upon receipt of an operation input from the trim angle operation unit, the controller may stop conducting the heel control.

[0019] (11) In the propulsion system of the boat according to one of the above aspects (1) to (10), the controller may be capable of conducting trim support control of causing the trim angle adjuster to adjust the trim angle to a trim support angle set in accordance with either a preset boat speed or a rotation speed of the propulsion machine, and in a case where a preset second condition is satisfied, the controller may conduct the heel control in addition to the trim support control, and may cause the trim angle adjuster to adjust the propulsion machine to the heel suppression angle set with reference to the trim support angle of the propulsion machine.

[0020] According to the aspect (1), while conducting the heel control, and in at least one propulsion machine, in a state in which the propulsion machine has the trim angle further inclined rearward in the propulsion direction of the hull than the first trim angle reference value, and in a case where the first condition is satisfied, the trim angle of the propulsion machine is adjusted so that the trim angle of the propulsion machine is the first trim angle reference value or the trim angle of the propulsion machine is further inclined forward in the propulsion direction than the first trim angle reference value. That is, in the case where the first condition is satisfied, the propulsion machine is lifted forward in the propulsion direction so that the trim angle of the propulsion machine is equal to or larger than the first trim angle reference value from a state in which the trim angle of the propulsion machine is further inclined rearward in the propulsion direction than the first trim angle reference value. Thus, in transitioning from the state of conducting the heel control to another state, the state can be smoothly transitioned so as not to impair the stability, the acceleration, the maximum speed, the energy efficiency, or the like of the boat, and so as not to make the boat operator feel uneasy.

[0021] According to the aspect (2), in a case where it is determined that the boat is in the turning state, it is determined that the first condition is satisfied. Thus, in transitioning from the state of conducting the heel control in the straight advancing state to the turning state, the propulsion machine is further inclined rearward in the propulsion direction than the first trim angle reference value, so that inhibition of the turning property can be suppressed. Therefore, inhibition of the stability, the acceleration, the maximum speed, the energy efficiency, and the like of the boat is suppressed, so that the state can be smoothly transitioned.

[0022] According to the aspect (3), in a case where it is determined that the boat is in the turning state, the trim angles of all of both the left and right propulsion machines are set to the first trim angle reference value. Thus, in a case where there is a propulsion machine further inclined forward than the first trim angle reference value, out of all propulsion machines, it becomes possible to prevent aeration at the time of turning in such a propulsion machine.

[0023] According to the aspect (4), when the boat operator performs a manual operation for adjusting the trim angle or the like of the propulsion machine and an operation input is received from the trim angle operation unit, it is determined that the first condition is satisfied. Thus, in transitioning from the state of conducting the heel control with the propulsion machine further inclined rearward in the propulsion direction than the first trim angle reference value to the state of manually operating the propulsion machine, it becomes possible to suppress an uneasy feeling of the boat operator. Therefore, the state can be smoothly transitioned.

[0024] According to the aspect (5), the intermediate member is provided between the hull and the propulsion machine to increase the inclination angle of the propulsion machine rearward in the propulsion direction. Thus, it becomes possible to further largely incline the propulsion machine rearward in the propulsion direction of the boat 1, and to further increase the trim angle in the negative direction, so that the heel control can be effectively conducted.

[0025] Furthermore, the first trim angle reference value is set, based on the trim angle of the propulsion machine in a state in which the propulsion machine is most inclined rearward in the propulsion direction in a case where the propulsion machine is provided on the hull without provision of the intermediate member. While conducting the heel control in a state in which the trim angle of the propulsion machine is further increased in the negative direction, and in transitioning from the state of conducting the heel control to another state, the trim angle of the propulsion machine is returned to the first trim angle reference value or more, so that the state can be transitioned smoothly.

[0026] According to the aspect (6), the heel control is conducted with the second trim angle reference value, as the lower limit value, that has been set, based on the trim angle of the propulsion machine in a case where the propulsion machine provided on the hull via the intermediate member is most inclined rearward in the propulsion direction, so that the heel control can be conducted effectively.

[0027] According to the aspect (7), in a case where it is determined that the boat is advancing straight, based on the detection value of the steering angle, conducting the heel control is enabled. Thus, while the boat is advancing straight, it becomes possible to smoothly conduct the heel control, so that the stability, the acceleration, the maximum speed, the energy efficiency, and the like can be improved.

[0028] According to the aspect (8), in a case where the heel angle is equal to or larger than the preset heel angle reference value, the heel control is conducted. Thus, as the first condition, in the state in which the boat is advancing straight, and in a case where the heel angle is large, it becomes possible to suppress the heel angle, so that the stability, the acceleration, the maximum speed, the energy efficiency, and the like of the boat can be improved.

[0029] According to the aspect (9), in a case where it is determined that the boat is in the turning state, based on the detection value of the steering angle, conducting the heel control is stopped. Accordingly, in the case where the boat is in the turning state, it becomes possible to suppress inhibition of the turning property due to the heel control.

[0030] According to the aspect (10), while conducting the heel control, upon receipt of the operation input from the trim angle operation unit, conducting the heel control is stopped. Thus, when the trim angle is manually operated by the boat operator of the boat, conducting the heel control is stopped, so that an uneasy feeling of the boat operator who has operated the trim angle can be suppressed.

[0031] According to the aspect (11), in a case where the preset second condition is satisfied, the heel control is conducted in addition to the trim support control, and the trim angle adjuster is caused to adjust the propulsion machine to the heel suppression angle set with reference to the trim support angle of the propulsion machine. Accordingly, in the case where the preset condition is satisfied, the heel control is conducted in addition to the trim support control, and thus it becomes possible to suppress the heel angle of the boat while automatically adjusting the trim angle. Therefore, in transitioning from the state of conducting the heel control to another state, the state can be smoothly transitioned so as not to impair the stability, the acceleration, the maximum speed, the energy efficiency, or the like of the boat, and so as not to make the boat operator feel uneasy.BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG. 1 is a plan view of a boat according to an embodiment;

[0033] FIG. 2 is a functional block diagram of a propulsion system of the above boat;

[0034] FIG. 3 is a side view of a propulsion machine of the above propulsion system;

[0035] FIG. 4 is a diagram illustrating an example of trim support control, heel control, hump control, and bogen control to be conducted in accordance with a boat speed in the above propulsion system;

[0036] FIG. 5 is a diagram illustrating an example of a set value of a trim support angle in the trim support control, the heel control, and the hump control to be conducted in accordance with the boat speed in above the propulsion system;

[0037] FIG. 6 is a view illustrating a state in which the trim support control is being conducted in the above propulsion system;

[0038] FIG. 7 is a view illustrating a state of conducting the heel control in a state in which the above boat is inclined to a port side;

[0039] FIG. 8 is a view illustrating a state of conducting the heel control in a state in which the above boat is inclined to a starboard side;

[0040] FIG. 9 is a flowchart illustrating a method for conducting the heel control while conducting the trim support control; and

[0041] FIG. 10 is a timing chart illustrating an example of the operation of the above propulsion system.DETAILED DESCRIPTION OF THE INVENTION

[0042] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that 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).

[0043] FIG. 1 is a plan view of the boat according to an embodiment. FIG. 2 is a functional block diagram of a propulsion system of the boat.

[0044] As illustrated in FIG. 1, the boat 1 includes: a hull 2; and a propulsion system 20, which is provided on the hull 2.

[0045] As illustrated in FIGS. 1 and 2, the propulsion system 20 includes a plurality of propulsion machines 3, an operation unit 7, a detector 6 (see FIG. 2), and a controller 8 (see FIG. 2).(Propulsion Machine)

[0046] As illustrated in FIG. 1, the propulsion machine 3 includes: a right propulsion machine 3a, which is provided on the right of a stern 2b with respect to the center line CL; and a left propulsion machine 3b, which is provided on the left of the stern 2b, with respect to the center line CL. The two propulsion machines 3 (the right propulsion machine 3a and the left propulsion machine 3b) are provided on the stern 2b of the hull 2 respectively on both right and left sides of the stern 2b, interposing the center line CL between them. That is, the boat 1 in the present embodiment is a so-called small-sized boat in which the two propulsion machines are provided. Hereinafter, in a case where it is not necessary to distinguish between the propulsion machines 3a and 3b, they will be collectively described as the propulsion machine 3.

[0047] FIG. 3 is a side view of a propulsion machine of the propulsion system.

[0048] As illustrated in FIG. 3, the propulsion machine 3 is, for example, an outboard motor. The propulsion machine 3 includes: a casing 31; a drive source 32; a drive shaft 33; a propulsor 34; and a shift switching mechanism 35.

[0049] The casing 31 is attached to a bracket 22, which is provided on the stern 2b, via a steering shaft (a swivel shaft) 36, which extends in an up-down direction. The propulsion machine 3 is attached to the hull 2 so as to be rotatable around the steering shaft 36 in accordance with the operation of a steering actuator 41 (see FIG. 2).

[0050] The drive source 32 is, for example, an internal combustion engine such as an engine. The drive source 32 is accommodated in an upper portion of the casing 31 with a crankshaft extending in the up-down direction. Dynamic power (an engine speed) of the drive source 32 is set, based on an opening degree of a throttle valve. The throttle valve is driven by the operation of a throttle actuator 42 (see FIG. 2). Note that the drive source 32 may be an electric motor.

[0051] The drive shaft 33 transmits the dynamic power generated by the drive source 32 to the propulsor 34 via the shift switching mechanism 35. The drive shaft 33 extends in the up-down direction in the casing 31. An upper end portion of the drive shaft 33 is connected with the drive source 32.

[0052] The propulsor 34 includes a propeller shaft 341 and propellers 342.

[0053] The propeller shaft 341 is provided at a lower end portion of the casing 31 so as to be rotatable around an axis along a front-rear direction. A front end portion of the propeller shaft 341 is connected with the shift switching mechanism 35 in the casing 31.

[0054] The propellers 342 are provided projecting outside of the casing 31 at a rear end portion of the propeller shaft 341. The propellers 342 rotate integrally with the propeller shaft 341.

[0055] The shift switching mechanism 35 includes a drive gear 351, a forward gear 352, a reverse gear 353, and a clutch 354.

[0056] The drive gear 351 is provided at a lower end portion of the drive shaft 33. The drive gear 351 is rotatable integrally with the drive shaft 33.

[0057] The forward gear 352 and the reverse gear 353 are rotatably provided at positions facing each other in the front-rear direction, interposing the drive gear 351 between them on the propeller shaft 341. The forward gear 352 and the reverse gear 353 are capable of meshing with the drive gear 351. The forward gear 352 and the reverse gear 353 rotate in opposite directions to each other in accordance with the rotation of the drive gear 351.

[0058] The clutch 354 switches between a connection state and a disconnection state of the dynamic power between either the forward gear 352 or the reverse gear 353 and the propeller shaft 341. The clutch 354 is provided to be rotatable integrally with the propeller shaft 341. The clutch 354 is provided to be movable in the front-rear direction along the propeller shaft 341 in accordance with the operation of a shift actuator 43. The clutch 354 alternatively meshes with the forward gear 352 and the reverse gear 353 to switch the rotation directions of the propeller shaft 341 and the propellers 342, and is capable of switching the propulsion direction of the boat 1.

[0059] The propulsion machine 3 is supported by the bracket 22, which is attached to the stern 2b of the hull 2, so as to be rotatable around a support shaft 38, which extends in the left-right direction. This enables the propulsion machine 3 to be rotatable (swingable) around the support shaft 38 with respect to a reference plane Fv. Here, the reference plane Fv denotes a virtual plane along a vertical plane that passes through the center axis of the support shaft 38 when the hull 2 is simply floated on the water surface.

[0060] Here, a trim angle θt is defined as an angle at which the direction in which the steering shaft 36 of the propulsion machine 3 extends is inclined in the front-rear direction around the support shaft 38 with respect to the reference plane Fv. In the present embodiment, with regard to the trim angle θt, a positive (plus) direction represents a direction in which a lower end portion of the propulsion machine 3 is apart rearward from the stern 2b, and a negative (minus) direction represents a direction in which the lower end portion of the propulsion machine 3 approaches the stern 2b.

[0061] The trim angle θt of the propulsion machine 3 is adjustable by a trim angle adjuster 45. The trim angle adjuster 45 uses an actuator, not illustrated, to rotate the propulsion machine 3 around the support shaft 38 within a preset angle range. The rotation of the propulsion machine 3 in the positive direction and the negative direction is restricted by hitting a stopper, not illustrated, or the like provided on the bracket 22.

[0062] In the present embodiment, the bracket 22 is attached to an attachment surface 2f, which is formed on the stern 2b, via an intermediate member 37. The intermediate member 37 is sandwiched between the bracket 22 and the attachment surface 2f. The intermediate member 37 is formed in a wedge shape having a thickness in the front-rear direction gradually decreasing from the top to the bottom. Thus, the bracket 22 is provided to be further inclined rearward than a case of being directly attached to the attachment surface 2f without the use of the intermediate member 37. This constitution enables setting of a larger rotation angle (rotation range) of the propulsion machine 3 in the negative direction.

[0063] In the present embodiment, the propulsion machine 3 is rotatable within a range between about 20 degrees at maximum in the positive direction and about −10 degrees at maximum in the negative direction with respect to the reference plane Fv, for example. Here, in a case where the propulsion machine 3 is directly attached to the bracket 22 of the hull 2 without provision of the intermediate member 37, the trim angle θt of the propulsion machine 3 in a state in which the propulsion machine 3 is most inclined rearward in the propulsion direction is, for example, about −5 degrees. In the controller 8 to be described later, the trim angle θt (=-about −5 degrees) is set as a first trim angle reference value θts1. Note that the first trim angle reference value θts1 may be set to an angle different from the trim angle θt of the propulsion machine 3 in the state in which the propulsion machine 3 is most inclined rearward in the propulsion direction in the case where the propulsion machine 3 is directly attached to the bracket 22 of the hull 2 without provision of the intermediate member 37.

[0064] In the present embodiment, the propulsion machine 3 is provided on the bracket 22 of the hull 2 via the intermediate member 37. By providing the propulsion machine 3 on the bracket 22 of the hull 2 via the intermediate member 37, the trim angle θt of the propulsion machine 3 in the state in which the propulsion machine 3 is most inclined rearward in the propulsion direction is, for example, about −10 degrees. That is, the intermediate member 37 makes the propulsion machine 3 inclined rearward in the propulsion direction by about 5 degrees in a negative direction. In the controller 8 to be described later, the trim angle θt (=about −10 degrees) is set as a second trim angle reference value θts2.(Operation Unit)

[0065] As illustrated in FIGS. 1 and 2, the operation unit 7 is provided to allow a boat operator to perform an operation input in order to navigate the boat 1. In the present embodiment, the operation unit 7 includes, for example, a steering angle inputter 71, a thrust inputter 72, a trim angle operation unit 73, and an operation inputter 74.

[0066] The steering angle inputter 71 is provided in a cockpit of the hull 2. The steering angle inputter 71 is, for example, a steering wheel provided to be rotatable clockwise and counterclockwise. The steering angle inputter 71 receives an operation input by the boat operator from the outside, in changing the course of the boat 1 (the hull 2). That is, the steering angle inputter 71 receives an operation, by the boat operator, for changing the direction (the steering angle) of the propulsion machine 3 around the steering shaft 36. The steering angle denotes an inclination angle of the propulsion machine 3 with respect to the center line CL in a plan view. In the present embodiment, the steering angle of the propulsion machine 3 when the course of the boat 1 is the straight advancing direction is set as the reference value (0 degrees). Note that as the steering angle inputter 71, in addition to the steering wheel, a joystick may be used, and the steering angle inputter 71 may be mounted as a switch or the like of the operation inputter 74.

[0067] The thrust inputter 72 is provided in the cockpit of the hull 2. The thrust inputter 72 is, for example, a throttle lever. In changing the thrust of the propulsion machine 3 or the shift position of the propulsion machine 3, the thrust inputter 72 receives an operation input from the outside by the boat operator. The thrust inputter 72 is constituted to be capable of reciprocating in accordance with rotation, sliding, or the like. The thrust inputter 72 is capable of reciprocating within an operation region in which three shift regions of the forward position F, the neutral position N, and the reverse position R are aligned. When the thrust inputter 72 is located at the forward position F, the propulsion machine 3 exerts thrust for moving the boat 1 forward. When the thrust inputter 72 is located at the reverse position R, the propulsion machine 3 exerts thrust for moving the boat 1 rearward. When the thrust inputter 72 is located at the neutral position N, the drive gear 351, which is illustrated in FIG. 3, is disconnected from the forward gear 352 and the reverse gear 353, and the propulsion machine 3 does not exert thrust for propelling the boat 1.

[0068] As illustrated in FIG. 1, a trim angle operation switch is provided as the trim angle operation unit 73 in the vicinity of the thrust inputter 72. The boat operator of the boat 1 is able to change the trim angle θt of the propulsion machine 3 by manually operating the trim angle operation switch (the trim angle operation unit 73).

[0069] The operation inputter 74 receives various operations on the boat 1. The operation inputter 74 is constituted to be manually operable by the boat operator, such as a multi-function display (MFD). Note that the operation inputter 74 may be an external device such as a mobile terminal connected to the boat 1 in a wired or wireless manner.(Detector)

[0070] The detector 6 illustrated in FIG. 2 detects a state (a navigation state) of the boat 1. In the present embodiment, the detector 6 includes a position sensor 61, a boat speed sensor 62, a steering angle sensor (a steering angle detector) 63, an inertial sensor 64, a trim operation sensor 65, a trim angle sensor 66, and an actual steering angle sensor 67.

[0071] The position sensor 61 detects the position of the thrust inputter 72. The position sensor 61 outputs, to the controller 8, a detection signal based on the position of the thrust inputter 72.

[0072] The boat speed sensor 62 detects a boat speed V of the boat 1. The boat speed sensor 62 is, for example, a global positioning system (GPS) or the like, and calculates the boat speed V, based on a positioning signal from a positioning satellite. Note that the boat speed sensor 62 may be an acoustic sensor or an electromagnetic sensor that detects the boat speed (a boat speed relative to the water) V of the boat 1. The boat speed sensor 62 may estimate the boat speed V, based on the engine speed. The boat speed sensor 62 outputs a signal indicating the detected boat speed V to the controller 8.

[0073] The steering angle sensor 63 detects an operation amount (a steering instruction angle) in accordance with the rotation operation on the steering angle inputter 71. The steering angle sensor 63 outputs, to the controller 8, a detection signal based on the steering instruction angle on the steering angle inputter 71.

[0074] The inertial sensor 64 detects the inclination in the roll direction of the hull 2, that is, a heel angle θh. The inertial sensor 64 is also capable of detecting an inclination or the like in the pitch direction of the hull 2. The inertial sensor 64 outputs, to the controller 8, detection signals based on the detected inclinations in the roll direction and the pitch direction of the hull 2.

[0075] The trim operation sensor 65 detects whether an operation input from the outside has been made on the trim angle operation switch, which serves as the trim angle operation unit 73. The trim operation sensor 65 outputs, to the controller 8, a detection signal indicating the presence or absence of the detected operation input.

[0076] The trim angle sensor 66 is provided in the trim angle adjuster 45. The trim angle sensor 66 detects an actual trim angle θt to be adjusted by the trim angle adjuster 45. The trim angle sensor 66 outputs, to the controller 8, a detection signal indicating the detected trim angle θt.

[0077] The actual steering angle sensor 67 is provided on the steering actuator 41. The actual steering angle sensor 67 detects the actual steering angle of the propulsion machine 3, and outputs the actual steering angle to the controller 8.(Controller)

[0078] The controller 8 integrally controls the operation of the boat 1 (the propulsion machine 3). The controller 8 is an integrated electronic control device 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 storage 80 such as 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.

[0079] The controller 8 includes a storage 80, an acquisitor 81, a determiner 82, and a drive processor 83.

[0080] The storage 80 records programs, various data, and the like necessary for navigation of the boat 1, such as the trim support control, the heel control, the hump control, and the bogen control.

[0081] The acquisitor 81 acquires detection results of various sensors of the detector 6.

[0082] The determiner 82 determines the state of the boat 1, based on information obtained by the acquisitor 81 and information stored in the storage 80.

[0083] The drive processor 83 controls operations of various actuators, based on a determination result by the determiner 82 and the information stored in the storage 80 or the acquisitor 81. In the present embodiment, in a case where the determiner 82 determines that a predetermined condition is satisfied, the drive processor 83 controls the operations of the trim angle adjuster 45, the steering actuator 41, and the like to conduct the trim support control, the heel control, the hump control, and the bogen control. In the present embodiment, when the boat 1 is in a straight advancing state, the drive processor 83 conducts the trim support control, the heel control, the hump control, and the bogen control. In the present embodiment, the drive processor 83 does not conduct the bogen control, when the boat 1 is not in the straight advancing state.(Trim Support Control)

[0084] FIG. 4 is a diagram illustrating an example of the trim support control, the heel control, the hump control, and the bogen control to be conducted in accordance with the boat speed in the propulsion system.

[0085] As illustrated in FIG. 4, when the boat 1 is in the straight advancing state, the drive processor 83 conducts the trim support control in the regions of the heel control, the hump control, and the bogen control in accordance with settings by the boat operator to be input from the trim angle operation unit 73 and the operation inputter 74, for example.

[0086] FIG. 5 is a diagram illustrating an example of set values of the trim support angles in the trim support control, the heel control, and the hump control to be conducted in accordance with the boat speed in the propulsion system.

[0087] As illustrated in FIG. 5, in the trim support control, the trim angle adjuster 45 is caused to adjust a trim angle θt to be a trim support angle θsp, which is set in accordance with a preset boat speed V (or rotation speed of the propulsion machine). In the present embodiment, in conducting the trim support control, the trim support angle θsp is set in accordance with the boat speed V to optimize stability, acceleration, a maximum speed, energy efficiency, and the like. The trim support angle θsp may be set in accordance with the rotation speed of the propulsion machine. Therefore, in the storage 80, the boat speed V (or the rotation speed of the propulsion machine) and the trim support angle θsp, at which the stability, the acceleration, the maximum speed, the energy efficiency, and the like are optimized, are stored beforehand in association with each other. In the example of FIG. 5, the trim support angle θsp is set in a stepwise manner with respect to the boat speed V (or the rotation speed of the propulsion machine).

[0088] Here, in conducting the trim support control, the trim support angle θsp of the propulsion machine 3 is set with the first trim angle reference value θts1 as a lower limit value.

[0089] The drive processor 83 acquires, from the storage 80, the trim support angle θsp, which is associated with the boat speed acquired by the acquisitor 81.

[0090] The drive processor 83 controls the trim angle adjuster 45 so that the trim angle θt of the propulsion machine 3 approaches the acquired trim support angle θsp.

[0091] FIG. 6 is a view illustrating a state in which the trim support control is being conducted in the propulsion system.

[0092] As illustrated in FIG. 6, in conducting the trim support control, the drive processor 83 sets the trim support angles θsp of the propulsion machines 3a and 3b on both sides in the left-right direction to the same value.(Heel Control)

[0093] As illustrated in FIG. 4, when the boat 1 is in the straight advancing state and the boat speed V is equal to or higher than the second threshold V2, while the trim support control is being conducted, and in a case where the determiner 82 determines that a preset second condition is satisfied, the drive processor 83 conducts the heel control in addition to the trim support control. Specifically, when the boat 1 is in the straight advancing state, while the trim support control is being conducted, and when the boat speed becomes equal to or higher than the second threshold V2, the drive processor 83 conducts the heel control in addition to the trim support control, that is, both the trim support control and the heel control.

[0094] In this case, the drive processor 83 conducts the heel control, in a case where the heel angle θh, which is detected by the inertial sensor 64, and which is the inclination in the roll direction of the hull 2, is equal to or larger than a preset heel angle reference value θhs (for example, several degrees). That is, in a case where the heel angle θh is smaller than the heel angle reference value θhs, the drive processor 83 continuously conducts the trim support control without conducting the heel control.

[0095] In conducting the heel control, the drive processor 83 sets a heel suppression angle θd as a target value in accordance with the heel angle θh of the hull 2. Here, the heel suppression angle θd denotes a trim angle of the propulsion machines 3 on both sides in the left-right direction for suppressing the inclination in the roll direction of the hull 2. The drive processor 83 calculates a heel suppression angle θd, which is capable of effectively suppressing the inclination in the roll direction of the hull 2, in accordance with the heel angle θh of the hull 2 in a preset calculation formula.

[0096] The drive processor 83 sets the heel suppression angle θd with reference to the trim support angle θsp of the propulsion machine 3 at such a timing. With regard to the trim support angle θsp, the drive processor 83 sets the heel suppression angle θd of the propulsion machine 3 on one side in the left-right direction to a value larger than the trim support angle θsp, and also sets the heel suppression angle θd of the propulsion machine 3 on the other side in the left-right direction to a value smaller than the trim support angle θsp.

[0097] In conducting the heel control, the heel suppression angle θd of the propulsion machine 3 is set within a range equal to or larger than the second trim angle reference value θts2 with the second trim angle reference value θts2 as a lower limit value.

[0098] FIG. 7 is a view illustrating a state of conducting the heel control in a state in which the boat is inclined to the port side. FIG. 8 is a view illustrating a state of conducting the heel control in a state in which the boat is inclined to the starboard side.

[0099] For example, as illustrated in FIG. 7, when the hull 2 is inclined to the port side, the drive processor 83 sets a heel suppression angle θd2 of the right propulsion machine 3a to a value larger than the trim support angle θsp, and sets a heel suppression angle θd1 of the left propulsion machine 3b to a value smaller than the trim support angle θsp. For example, as illustrated in FIG. 8, when the hull 2 is inclined to the starboard side, the drive processor 83 sets the heel suppression angle θd1 of the left propulsion machine 3b to a value larger than the trim support angle θsp, and sets the heel suppression angle θd2 of the right propulsion machine 3a to a value smaller than the trim support angle θsp.

[0100] The drive processor 83 calculates the heel suppression angles θd1 and θd2 with reference to the trim support angle θsp set at such a timing, based on the heel angle θh of the hull 2 at such a timing that has been acquired by the acquisitor 81. The drive processor 83 calculates, in a preset calculation formula, a trim angle addition value Δθt1 to be added to the trim support angle θsp as a reference for the propulsion machine 3 on one side in the left-right direction and a trim angle subtraction value Δθt2 to be subtracted from the trim support angle θsp as a reference for the propulsion machine 3 on the other side in the left-right direction. Here, the absolute value of the trim angle addition value Δθt1 and the absolute value of the trim angle subtraction value Δθt2 are preferably identical to each other. Here, the absolute value of the trim angle addition value Δθt1 and the absolute value of the trim angle subtraction value Δθt2 are set to be equal to or smaller than a preset value. Note that the absolute value of the trim angle addition value Δθt1 and the absolute value of the trim angle subtraction value Δθt2 may be different from each other.

[0101] When the hull 2 is inclined to the port side, the drive processor 83 calculates the heel suppression angle θd1 of the left propulsion machine 3b in the following equation (1), and calculates the heel suppression angle θd2 of the right propulsion machine 3a in the following equation (2).θ⁢d⁢1=θ⁢sp-Δθ⁢t⁢2(1)θ⁢d⁢2=θ⁢sp+Δ⁢θ⁢t⁢1(2)

[0102] When the hull 2 is inclined to the starboard side, the drive processor 83 calculates the heel suppression angle θd1 of the left propulsion machine 3b in the following equation (3), and calculates the heel suppression angle θd2 of the right propulsion machine 3a in the following equation (4).θ⁢d⁢1=θ⁢sp+Δθ⁢t⁢1(3)θ⁢d⁢2=θ⁢sp-Δθ⁢t⁢2(4)

[0103] The drive processor 83 sets the heel suppression angles θd1 and θd2 that have been calculated to the target values, and causes the trim angle adjuster 45 to adjust the trim angles θt of the propulsion machines 3 (3a, 3b) so as to approach the heel suppression angles θd1 and θd2.

[0104] While conducting the heel control, in a case where the determiner 82 determines that the boat speed V becomes equal to or lower than a preset third threshold V3, the drive processor 83 stops conducting the heel control. Here, the third threshold V3 is set to be lower than the second threshold V2.

[0105] In addition, while conducting the heel control, the determiner 82 determines whether the trim angle θt of at least one propulsion machine 3 (one of the propulsion machines 3) is smaller than the first trim angle reference value θts1. In a case where the trim angle θt of at least one propulsion machine 3 is smaller than the first trim angle reference value θts1, the determiner 82 determines whether a preset first condition is satisfied. In the present embodiment, as the first condition, examples include

[0106] Condition A: The boat 1 is in a turning state, and

[0107] Condition B: The trim angle of the propulsion machine 3 has been manually operated.

[0108] In a case where at least one of the conditions A and B is satisfied, the determiner 82 determines that the first condition is satisfied.

[0109] In a case where the first condition is satisfied, the drive processor 83 causes the trim angle adjuster 45 to drive the propulsion machine 3 having the trim angle θt smaller than the first trim angle reference value θts1 so as to adjust the trim angle θt to the first trim angle reference value θts1, for example.

[0110] In a case where the condition A of the first condition is satisfied, the drive processor 83 causes the trim angles θt of all the propulsion machines 3 on both sides in the left-right direction to be adjusted to the first trim angle reference value θts1. In addition, in a case where the condition B of the first condition is satisfied, the drive processor 83 causes the trim angle θ to be adjusted to the first trim angle reference value θts1 for the propulsion machine 3 having the trim angle θt smaller than the first trim angle reference value θts1, and causes the trim angle θt to be adjusted in accordance with the manual operation for the propulsion machine 3 having the trim angle θt equal to or larger than the first trim angle reference value θts1.

[0111] As a specific example, for example, an assumed condition is a case where while conducting the heel control, the trim angle θt (for example, about −10 degrees) of the right propulsion machine 3 is smaller than the first trim angle reference value θts1 (about −5 degrees) and the trim angle θt (for example, about 0 degrees) of the left propulsion machine 3 is larger than the first trim angle reference value θts1.

[0112] Under such an assumed condition, when the boat 1 is in the turning state and the condition A is satisfied, all the propulsion machines 3 on both sides in the left-right direction are set to the first trim angle reference value θts1 (about −5 degrees). Thus, in the right propulsion machine 3 having a smaller trim angle θt than the first trim angle reference value θts1, inhibition of the turning property can be suppressed. In the left propulsion machine 3 having a larger trim angle θt than the first trim angle reference value θts1, the aeration is suppressed.

[0113] In addition, under the above assumed condition, when the trim angle of the propulsion machine 3 is manually operated and the condition B is satisfied, only the right propulsion machine 3 having a smaller trim angle θt than the first trim angle reference value θts1 is increased to the first trim angle reference value θts1 (about −5 degrees). In this case, in a case where the trim angle θt of the left propulsion machine 3 is equal to or larger than the first trim angle reference value θts1 (about −5 degrees), the trim angle θt is adjusted in accordance with the manual operation.

[0114] In addition, while conducting the heel control, in a case where the steering angle sensor 63 receives the input of the steering angle from the steering angle inputter 71, the determiner 82 determines whether the boat 1 is in the turning state, based on the received input value of the steering angle. Upon determination that the boat 1 is in the turning state, the drive processor 83 stops conducting the trim support control and the heel control.

[0115] In addition, while conducting the heel control, in a case where the determiner 82 determines that the operation input by the boat operator is received from the trim angle operation unit 73, the drive processor 83 stops conducting the heel control.(Hump Control)

[0116] In addition, as illustrated in FIG. 4, when the boat 1 is in the straight advancing state and the boat speed V is equal to or higher than the first threshold V1, and in a case where the determiner 82 determines that the preset third condition is satisfied, the drive processor 83 conducts the hump control. When the boat 1 is in the straight advancing state, the boat speed V is equal to or higher than the first threshold V1, and in a case where the boat speed V is lower than the second threshold V2, the drive processor 83 conducts the hump control.

[0117] The hump control is conducted to suppress excessive lifting of a bow 2a when the bow 2a is largely lifted with respect to the stern 2b. In conducting the hump control, the drive processor 83 sets the trim angles θt of the propulsion machines 3a and 3b on both sides in the left-right direction to the same value.(Bogen Control)

[0118] In addition, in a case where the boat speed V is lower than the first threshold V1, the drive processor 83 conducts the bogen control. In the bogen control, the plurality of propulsion machines 3 are steered in a direction intersecting the front-rear direction of the hull 2 in a yaw direction. When the boat 1 is in the straight advancing state and the boat speed V is lower than the first threshold V1, the left and right propulsion machines 3 are rotated in directions opposite to each other around the swivel axis and at almost the same steering angle in the bogen control. In the bogen control, it becomes possible to reduce the forward propulsion force that works on the entirety of the hull 2 and to navigate the hull 2 at a low speed or an extremely low speed, as compared with a case where the propulsion machines 3 are disposed in parallel with the front-rear direction of the hull 2. Note that in the present embodiment, there is no limitation to the specific content of the bogen control.(Control Method of Propulsion System)

[0119] Next, an operation method of the propulsion system will be described. Processing to be described below is repeatedly performed, for example, at a predetermined control cycle (for example, several tens of milliseconds).

[0120] Here, the trim support control is conducted at an appropriate timing in accordance with a setting of the boat operator. In the trim support control, the controller 8 sets the trim support angle θsp, at which the stability, the acceleration, the maximum speed, the energy efficiency, and the like are optimized, as the target value in accordance with the boat speed V. The controller 8 controls the trim angle adjuster 45 so that the trim angles θt of both the left and right propulsion machines 3 approach the trim support angle θsp, which is set as the target value.

[0121] FIG. 9 is a flowchart illustrating a method for conducting the heel control while conducting the trim support control.

[0122] While conducting the trim support control, the controller 8 causes the acquisitor 81 to acquire a detection result of the boat speed in the boat speed sensor 62 at a predetermined control cycle, in step S141.

[0123] In step S142, the controller 8 determines whether the boat speed V is equal to or higher than the second threshold V2, based on the detection result of the boat speed sensor 62.

[0124] In a case where the determination result in step S142 is “No” (V<V2), the processing ends. The processing from step S141 is repeated at every predetermined control cycle, and the trim support control is continuously conducted. In a case where the determination result in step S142 is “Yes” (V≥V2), the processing proceeds to step S143, and the controller 8 enables conducting the heel control. In other words, the controller 8 sets the heel control to a standby state.

[0125] Next, in step S144, the acquisitor 81 acquires a detection result of the heel angle θh of the hull 2 in the inertial sensor 64.

[0126] In step S145, the controller 8 determines whether the heel angle θh is equal to or larger than the heel angle reference value θhs, based on the detection result of the inertial sensor 64.

[0127] In a case where the determination result in step S145 is “No” (θh<θhs), the processing returns to step S144. After a predetermined control cycle elapses, step S144 is repeatedly performed.

[0128] In a case where the determination result in step S145 is “Yes” (θh≥θhs), the processing proceeds to step S146.

[0129] In step S146, the controller 8 conducts the heel control in addition to the trim support control. In step S146, the controller 8 sets the heel suppression angle θd in accordance with the heel angle θh of the hull 2. The controller 8 sets the heel suppression angle θd with reference to the trim support angle θsp of the propulsion machine 3 at such a timing. The drive processor 83 calculates the trim angle addition value Δθt1 to be added to the trim support angle θsp as a reference for the propulsion machine 3 on one side in the left-right direction and the trim angle subtraction value Δθt2 to be subtracted from the trim support angle θsp as a reference for the propulsion machine 3 on the other side in the left-right direction in a preset calculation formula, based on the heel angle θh of the hull 2 at such a timing that has been acquired by the acquisitor 81.

[0130] In a case where the hull 2 is inclined to the port side, the drive processor 83 calculates the heel suppression angle θd1 of the left propulsion machine 3b in the above equation (1), and calculates the heel suppression angle θd2 of the right propulsion machine 3a in the above equation (2). In a case where the hull 2 is inclined to the starboard side, the drive processor 83 calculates the heel suppression angle θd1 of the left propulsion machine 3b in the above equation (3), and calculates the heel suppression angle θd2 of the right propulsion machine 3a in the above equation (4).

[0131] The drive processor 83 sets the heel suppression angles θd1 and θd2 that have been calculated to the target values, and causes the trim angle adjuster 45 to adjust the trim angles θt of the propulsion machines 3 (3a and 3b).

[0132] In step S147, while conducting the heel control, the controller 8 determines whether the boat speed V becomes equal to or lower than the preset third threshold V3.

[0133] In a case where the determination result in step S147 is “No” (in a case where the boat speed V is not equal to or lower than the third threshold V3), the processing proceeds to step S149.

[0134] In a case where the determination result in step S147 is “Yes” (in a case where the boat speed V becomes equal to or lower than the third threshold V3), the processing proceeds to step S148, conducting the heel control is stopped, and only the trim support control continues.

[0135] In step S149, the controller 8 determines whether an operation input of manual operation by the boat operator is received from the trim angle operation unit 73.

[0136] In a case where the determination result in step S149 is “No” (in a case where the manual operation by the boat operator is not performed), the processing proceeds to step S153.

[0137] In a case where the determination result in step S149 is “Yes” (in a case where the manual operation by the boat operator is performed), the processing proceeds to step S150.

[0138] In step S150, the controller 8 determines whether the trim angle θt of at least one of the propulsion machines 3 is smaller than the first trim angle reference value θts1. In other words, the controller 8 determines whether the trim angle θt of at least one of the propulsion machines 3 at such a timing is further largely inclined on the negative side (rearward in the propulsion direction) than the first trim angle reference value θts1.

[0139] In a case where the determination result in step S150 is “No” (in a case where the trim angles θt of both propulsion machines 3 are equal to or larger than the first trim angle reference value θts1), the processing skips step S151, and proceeds to step S152.

[0140] In a case where the determination result in step S150 is “Yes” (in a case where the trim angle θt of at least one of the propulsion machines 3 is smaller than the first trim angle reference value θts1), the processing proceeds to step S151.

[0141] In a case where the determination result in step S149 is “Yes” and the condition B is satisfied, the controller 8 causes the trim angle adjuster 45 to return the trim angle θt of the propulsion machine 3 having a smaller trim angle θt than the first trim angle reference value θts1 to the first trim angle reference value θts1, in step S151. The controller 8 returns the trim angle θt of the propulsion machine 3 that is further largely inclined on the negative side than the first trim angle reference value θts1, to the first trim angle reference value θts1. Note that the controller 8 may cause the propulsion machine 3 to return the trim angle θt of the propulsion machine 3 further on the positive side than the first trim angle reference value θts1 (a state in which the propulsion machine 3 is inclined further forward in the propulsion direction than the first trim angle reference value θts1).

[0142] In this situation, for the propulsion machine 3 having the trim angle θt equal to or larger than the first trim angle reference value θts1 at such a timing, the controller 8 causes the trim angle adjuster 45 to adjust the trim angle θt in accordance with the operation input from the trim angle operation unit 73.

[0143] In step S152, conducting the heel control is stopped. After a predetermined control cycle elapses, the processing from the above S141 is repeated.

[0144] In step S153, the controller 8 determines whether the boat 1 is in the turning state. In this case, the controller 8 determines whether the boat 1 is in the turning state, based on the actual steering angle detected by the actual steering angle sensor 67.

[0145] In a case where the determination result in step S153 is “No” (in a case where the boat 1 is not in the turning state, that is, in a case where the boat 1 is advancing straight), the processing ends. After a predetermined control cycle elapses, the processing from the above step S141 is repeated.

[0146] In a case where the determination result in step S153 is “Yes” (in a case where the boat 1 is in the turning state), the processing proceeds to step S150, and the controller 8 determines whether the trim angle θt of at least one of the propulsion machines 3 is smaller than the first trim angle reference value θts1, based on a detection result of the inertial sensor 64.

[0147] In a case where the determination result in step S150 is “No”, the processing skips step S151, and proceeds to step S152.

[0148] In a case where the determination result in step S150 is “Yes”, the processing proceeds to step S151.

[0149] In a case where the determination result in step S153 is “Yes” and the above condition A is satisfied in step S153, the controller 8 causes the trim angle adjuster 45 to return the trim angles θt of all the propulsion machines 3 to the first trim angle reference value θts1 in step S151.

[0150] In step S152, conducting the trim support control and the heel control is stopped. Then, in a case where the turning state returns to the straight advancing state, the processing illustrated in the flowchart of FIG. 9 is performed.

[0151] FIG. 10 is a timing chart illustrating an example of the operation of the propulsion system.

[0152] In FIG. 10, “0” indicates that a determination result in the controller 8 is “No” or the control by the controller 8 is “OFF”, and “1” indicates that the determination result in the controller 8 is “Yes” or the control by the controller 8 is “ON” in each a “boat speed determination flag”, a “straight advancing determination flag”, a “heel control conducting determination flag”, a “trim operation determination flag”, a “left trim angle UP” flag, a “right trim angle UP” flag, a “left trim angle DW (Down)” flag, a “right trim angle DW” flag, and an “instruction position matching determination flag”.

[0153] As illustrated in FIG. 10, when the boat 1 is advancing straight and the trim support control is being conducted, and, for example, when the lever opening rate is increased in accordance with the operation by the boat operator on the thrust inputter 72 (time t1), the boat speed V increases.

[0154] When the boat speed V exceeds the second threshold V2 (time t2), the boat speed determination flag of the controller 8 in the above step S142 changes from “0” to “1”. On the other hand, the straight advancing determination flag is “0” and it is determined that the boat 1 is in the straight advancing state, based on a detection value of the actual steering angle sensor 67. Thus, the condition that the boat 1 is in the straight advancing state and the boat speed V is equal to or higher than the second threshold V2 is satisfied, and the heel control conducting determination flag changes from “0” to “1”.

[0155] Then, the controller 8 sets the heel control mode to “ON”, and starts conducting the heel control. In this state, the heel angle θh of the boat 1 is smaller than the heel angle reference value θhs. Thus, the controller 8 sets a trim angle operation instruction determination flag to a mode “0” in which the trim angle θt of the propulsion machine 3 is not adjusted by the heel control.

[0156] Then, when the heel angle θh to the right of the boat 1 exceeds the heel angle reference value θhs (time t3), the controller 8 conducting the heel control switches the trim angle operation instruction determination flag to a mode “1” of increasing the trim angle θt of the left propulsion machine 3 and decreasing the trim angle θt of the right propulsion machine 3. In response to this, in order to suppress the heel angle θh to the right, the controller 8 sets the left trim angle UP flag and the right trim angle DW flag to “1”, increases the trim angle θt of the left propulsion machine 3, and decreases the trim angle θt of the right propulsion machine 3.

[0157] Then, when the trim angle θt of the right propulsion machine 3 decreases to the second trim angle reference value θts2 (about −10 degrees), which serves as a trim angle lower limit value (time t4), the controller 8 returns the right trim angle DW flag to “0”. Since then, the trim angle θt of the right propulsion machine 3 maintains the trim angle lower limit value.

[0158] When the heel angle θh of the boat 1 decreases in the heel control, and falls below a predetermined threshold at the time of return (time t5), the controller 8 returns the trim angle operation instruction determination flag to the mode “0”. Thus, the left trim angle UP flag returns to “0”. Since then, the left propulsion machine 3 maintains the trim angle θt at such a timing.

[0159] Then, when the boat operator performs the steering operation in the right direction on the steering angle inputter 71 (time t6), the rightward steering angle increases. When the actual steering angle detected by the actual steering angle sensor 67 becomes larger than the rightward steering angle threshold (time t7), the straight advancing determination flag changes from “1” to “0”. Thus, it is determined in step S153 that the boat 1 is in the turning state, and the heel control conducting determination flag changes from “1” to “0”.

[0160] Then, the controller 8 transitions to the processing of releasing the heel control in steps S150 and S151, and switches the trim angle operation instruction determination flag to a mode “2” of decreasing the trim angle θt of the left propulsion machine 3 and increasing the trim angle θt of the right propulsion machine 3, based on the state of the trim angle θt of each propulsion machine 3 at such a timing. Accordingly, the controller 8 sets the left trim angle DW flag to “1” and the right trim angle UP flag to “1”. Then, the trim angle θt of the left propulsion machine 3 decreases, and the trim angle θt of the right propulsion machine 3 increases.

[0161] Then, both the trim angle θt of the left propulsion machine 3 and the trim angle θt of the right propulsion machine 3 return to the first trim angle reference value θts1. When the instruction position matching determination flag is “1” (time t8), the controller 8 ends the processing of releasing the heel control.

[0162] In this manner, the propulsion system 20 according to the present embodiment conducts the heel control. In addition, in at least one propulsion machine 3, in a state in which the propulsion machine 3 has the trim angle θt further inclined rearward in the propulsion direction of the hull 2 than the first trim angle reference value θts1, and in a case where the first condition is satisfied, the propulsion system 20 adjusts the trim angle θt of the propulsion machine 3 so that the trim angle θt of the propulsion machine 3 is the first trim angle reference value θts1 or the trim angle θt of the propulsion machine 3 is further inclined forward in the propulsion direction than the first trim angle reference value θts1. That is, in the case where the first condition is satisfied, the propulsion machine 3 is lifted forward in the propulsion direction so that the trim angle θt of the propulsion machine 3 is equal to or larger than the first trim angle reference value θts1 from a state in which the trim angle θt of the propulsion machine 3 is further inclined rearward in the propulsion direction than the first trim angle reference value θts1. Thus, in transitioning from the state of conducting the heel control to another state, the state can be smoothly transitioned so as not to impair the stability, the acceleration, the maximum speed, the energy efficiency, or the like of the boat 1, and so as not to make the boat operator feel uneasy.

[0163] In addition, in a case where it is determined that the boat 1 is in the turning state, the propulsion system 20 according to the present embodiment determines that the first condition is satisfied. Thus, in transitioning from the state of conducting the heel control to the turning state, inhibition of the turning property due to an excessively small value of the trim angle θt of the propulsion machine 3 is suppressed, so that the state can be smoothly transitioned.

[0164] Further, in the propulsion system 20 according to the present embodiment, in a case where it is determined that the boat 1 is in the turning state, the trim angles θt of all of both the left and right propulsion machines 3 are set to the first trim angle reference value θts1. Thus, in a case where there is a propulsion machine 3 further inclined forward than the first trim angle reference value θts1, out of all propulsion machines 3, it becomes possible to prevent aeration at the time of turning in such a propulsion machine 3.

[0165] In addition, the propulsion system 20 according to the present embodiment determines that the first condition is satisfied, when the boat operator performs a manual operation for adjusting the trim angle θt or the like of the propulsion machine 3 and an operation input is received from the trim angle operation unit 73. Thus, when the propulsion machine 3 is manually operated from the state of conducting the heel control, it becomes possible to suppress an uneasy feeling of the boat operator due to an excessively small trim angle θt of the propulsion machine 3, so that the state can be smoothly transitioned.

[0166] In addition, the propulsion system 20 according to the present embodiment includes the intermediate member 37 between the hull 2 and the propulsion machine 3 to increase the inclination angle of the propulsion machine 3 rearward in the propulsion direction. This enables the propulsion machine 3 to be further largely inclined rearward in the propulsion direction of the boat 1, and enables the trim angle θt to be larger in the negative direction, so that the heel control can be effectively conducted.

[0167] Furthermore, the first trim angle reference value θts1 is set, based on the trim angle θt of the propulsion machine 3 in a state in which the propulsion machine 3 is most inclined rearward in the propulsion direction in a case where the propulsion machine 3 is provided on the hull 2 without provision of the intermediate member 37. While conducting the heel control in a state in which the trim angle θt of the propulsion machine 3 is made larger in the negative direction, the trim angle θt of the propulsion machine 3 is returned to the first trim angle reference value θts1, in transitioning from the state of conducting the heel control to another state, so that the boat operator is less likely to have an uneasy feeling or the like.

[0168] In addition, the propulsion system 20 according to the present embodiment conducts the heel control with the second trim angle reference value θts2, as the lower limit value, that has been set, based on the trim angle θt of the propulsion machine 3 in a case where the propulsion machine 3 provided on the hull 2 via the intermediate member 37 is most inclined rearward in the propulsion direction, so that the heel control can be conducted effectively.

[0169] In addition, the propulsion system 20 according to the present embodiment enables conducting the heel control in a case where it is determined that the boat 1 is advancing straight, based on the input value of the steering angle. Thus, while the boat 1 is advancing straight, it becomes possible to smoothly conduct the heel control, so that the stability, the acceleration, the maximum speed, the energy efficiency, and the like can be improved.

[0170] In addition, the propulsion system 20 according to the present embodiment conducts the heel control in the case where the heel angle θh is equal to or larger than the preset heel angle reference value θhs. Thus, as the first condition, in the state in which the boat 1 is advancing straight and in the case where the heel angle θh is large, it becomes possible to suppress the heel angle θh, so that the stability, the acceleration, the maximum speed, the energy efficiency, and the like of the boat 1 can be improved.

[0171] In addition, the propulsion system 20 according to the present embodiment stops conducting the heel control, in a case where it is determined that the boat 1 is in the turning state, based on the input value of the steering angle. Accordingly, in the case where the boat 1 is in the turning state, it becomes possible to suppress inhibition of the turning property due to the heel control.

[0172] Further, while conducting the heel control, the propulsion system 20 according to the present embodiment stops conducting the heel control upon receipt of the operation input from the trim angle operation unit 73. Thus, when the trim angle θt is manually operated by the boat operator of the boat 1, conducting the heel control is stopped, so that an uneasy feeling of the boat operator who has operated the trim angle θt can be suppressed.

[0173] In addition, in the case where the preset second condition is satisfied, the propulsion system 20 according to the present embodiment conducts the heel control in addition to the trim support control, and causes the trim angle adjuster 45 to adjust the propulsion machine 3 to the heel suppression angle θd set with reference to the trim support angle θsp of the propulsion machine 3. Accordingly, in the case where the preset condition is satisfied, the heel control is conducted in addition to the trim support control, and thus it becomes possible to suppress the heel angle θh of the boat 1 while automatically adjusting the trim angle θt. Therefore, in transitioning from the state of conducting the heel control to another state, it becomes possible to smoothly transition the state so as not to impair the stability, the acceleration, the maximum speed, the energy efficiency, or the like of the boat 1, and so as not to make the boat operator feel uneasy.

[0174] Note that the present invention is not limited to the above-described embodiments with reference to the drawings, and various modifications are conceivable within the technical scope.

[0175] For example, in the above embodiment, the trim support control, the heel control, and the like are conducted, based on the boat speed V. However, the trim support control, the heel control, and the like may be conducted, based on the rotation speed of the propulsion machine 3 instead of the boat speed V.

[0176] In addition, in the above embodiment, while the boat 1 is advancing straight, the case of conducting only the trim support control and the case of conducting both the trim support control and the heel control in accordance with the boat speed V have been given as examples. However, while the boat 1 is advancing straight, it is also possible to conduct only the heel control in accordance with the boat speed V.

[0177] In the above embodiment, one propulsion machine 3 is provided on each of both left and right sides, but a plurality of propulsion machines 3 may be provided on each of both left and right sides.

[0178] In addition, the procedure and contents of the control conducted by the controller 8 can be changed as appropriate.

[0179] Then, the constitution in the above embodiment is an example of the present invention, and various changes can be made without departing from the gist of the present invention.

[0180] While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary 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

[0182] 2 Hull

[0183] 3 Propulsion Machine

[0184] 6 Detector

[0185] 8 Controller

[0186] 20 Propulsion system

[0187] 32 Drive source

[0188] 34 Propulsor

[0189] 36 Steering shaft

[0190] 37 Intermediate member

[0191] 45 Trim angle adjuster

[0192] 63 Steering angle sensor (steering angle detector)

[0193] 71 Steering angle inputter

[0194] 73 Trim angle operation unit

Claims

1. A propulsion system of a boat, the propulsion system comprising:at least one propulsion machine including a drive source, and a propulsor configured to generate thrust with dynamic power transmitted from the drive source, the at least one propulsion machine being provided on each of both sides in a left-right direction with respect to a center of a hull;a trim angle adjuster configured to adjust a trim angle of each of the propulsion machines on the both sides in the left-right direction with respect to the hull; anda controller configured to control the trim angle adjuster, whereinthe controller is capable of conducting heel control of causing the trim angle adjuster to adjust the trim angle to a heel suppression angle set in accordance with an inclination in a roll direction of the hull to suppress the inclination in the roll direction of the hull, andwhile conducting the heel control, in a state in which the at least one propulsion machine has a trim angle further inclined rearward in a propulsion direction of the hull than a preset first trim angle reference value, and in a case where a preset first condition is satisfied, the controller causes the trim angle adjuster to adjust the trim angle of the propulsion machine so that the trim angle of the propulsion machine is the first trim angle reference value or so that the propulsion machine has the trim angle further inclined forward in the propulsion direction than the first trim angle reference value.

2. The propulsion system of the boat according to claim 1, further comprising a steering angle detector configured to detect a steering angle around a steering shaft of the propulsion machine with respect to the hull in accordance with an external input, whereinin a case where it is determined that the boat is in a turning state, based on a detection value of the steering angle detected by the steering angle detector, the controller determines that the first condition is satisfied.

3. The propulsion system of the boat according to claim 2, whereinin the case where it is determined that the boat is in the turning state, the trim angle adjuster adjusts the trim angle of the propulsion machine so that the trim angles of the propulsion machines become the first trim angle reference value in all of the propulsion machine on the both sides in the left-right direction.

4. The propulsion system of the boat according to claim 1, further comprising a trim angle operation unit configured to operate the trim angle adjuster in accordance with an external input, whereinupon receipt of an operation input from the trim angle operation unit, the controller determines that the first condition is satisfied.

5. The propulsion system of the boat according to claim 2, further comprising a trim angle operation unit configured to operate the trim angle adjuster in accordance with an external input, whereinupon receipt of an operation input from the trim angle operation unit, the controller determines that the first condition is satisfied.

6. The propulsion system of the boat according to claim 1, further comprising an intermediate member provided between the hull and the propulsion machine, the intermediate member increasing a rearward inclination angle in the propulsion direction of the propulsion machine, whereinthe first trim angle reference value is set, based on the trim angle of the propulsion machine in a state in which the propulsion machine is most inclined rearward in the propulsion direction in a case where the propulsion machine is provided on the hull without provision of the intermediate member.

7. The propulsion system of the boat according to claim 2, further comprising an intermediate member provided between the hull and the propulsion machine, the intermediate member increasing a rearward inclination angle in the propulsion direction of the propulsion machine, whereinthe first trim angle reference value is set, based on the trim angle of the propulsion machine in a state in which the propulsion machine is most inclined rearward in the propulsion direction in a case where the propulsion machine is provided on the hull without provision of the intermediate member.

8. The propulsion system of the boat according to claim 6, whereinin conducting the heel control, the controller causes the trim angle adjuster to adjust the trim angle of the propulsion machine with a second trim angle reference value as a lower limit value, the second trim angle reference value being set, based on the trim angle of the propulsion machine in a case where the propulsion machine provided on the hull via the intermediate member is most inclined rearward in the propulsion direction.

9. The propulsion system of the boat according to claim 2, whereinin a case where it is determined that the boat is advancing straight, based on the detection value of the steering angle, the controller enables conducting the heel control.

10. The propulsion system of the boat according to claim 9, further comprising a heel angle detector configured to detect a heel angle serving as an inclination in a roll direction of the hull, whereinin a case where the heel angle is equal to or larger than a preset heel angle reference value, the controller conducts the heel control.

11. The propulsion system of the boat according to claim 2, whereinwhile conducting the heel control, in a case where it is determined that the boat is in the turning state, based on the detection value of the steering angle, the controller stops conducting the heel control.

12. The propulsion system of the boat according to claim 1, further comprising a trim angle operation unit configured to operate the trim angle adjuster in accordance with an external input, whereinwhile conducting the heel control, upon receipt of an operation input from the trim angle operation unit, the controller stops conducting the heel control.

13. The propulsion system of the boat according to claim 2, further comprising a trim angle operation unit configured to operate the trim angle adjuster in accordance with an external input, whereinwhile conducting the heel control, upon receipt of an operation input from the trim angle operation unit, the controller stops conducting the heel control.

14. The propulsion system of the boat according to claim 1, whereinthe controller is capable of conducting trim support control of causing the trim angle adjuster to adjust the trim angle to a trim support angle set in accordance with either a preset boat speed or a rotation speed of the propulsion machine, andin a case where a preset second condition is satisfied, the controller conducts the heel control in addition to the trim support control, and causes the trim angle adjuster to adjust the propulsion machine to the heel suppression angle set with reference to the trim support angle of the propulsion machine.

15. The propulsion system of the boat according to claim 2, whereinthe controller is capable of conducting trim support control of causing the trim angle adjuster to adjust the trim angle to a trim support angle set in accordance with either a preset boat speed or a rotation speed of the propulsion machine, andin a case where a preset second condition is satisfied, the controller conducts the heel control in addition to the trim support control, and causes the trim angle adjuster to adjust the propulsion machine to the heel suppression angle set with reference to the trim support angle of the propulsion machine.

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