MARINE PROPULSION SYSTEM

Abstract

 A marine propulsion system (100) includes a controller (14) configured or programmed to perform an in-wave vessel speed control such that a vessel speed (V) becomes equal to or higher than a predetermined minimum vessel speed (V0) in an in-wave vessel speed control mode in which an in-wave vessel speed control is performed to adjust the vessel speed (V) based on information (Ia) regarding upward-downward movement of a hull (10).

Description

[0001] The present invention relates to a marine propulsion system and a method for controlling a marine vessel.

[0002] A marine propulsion system that performs a control to adjust a vessel speed based on information regarding upward-downward movement of a hull when waves are occurring is known in general. Such a marine propulsion system is disclosed in JP 6-211190 A, for example.

[0003] JP 6-211190 A discloses a marine operation control device (marine propulsion system) that performs a control to adjust a vessel speed based on information regarding upward-downward movement of a hull when waves are occurring. The marine operation control device described in JP 6-211190 A detects the degree of impact received by the hull during voyage using an acceleration detector that detects an acceleration of the hull in an upward-downward direction, for example, and decelerates the hull when the acceleration of the hull in the upward-downward direction, for example, detected by the acceleration detector exceeds a preset setting limit.

[0004] However, in the marine operation control device described in JP 6-211190 A, the hull is decelerated when the acceleration of the hull in the upward-downward direction, for example, detected by the acceleration detector exceeds the preset setting limit, and thus when the hull continuously rides over a relatively large wave, the hull may continue to be decelerated, and the vessel speed may become excessively low. When the vessel speed becomes excessively low, the hull may be unable to plane, or may be able to hardly move forward, for example. Therefore, a marine propulsion system and a marine vessel are desired that each prevent an excessive decrease in the vessel speed while a control is performed to adjust the vessel speed based on the information regarding upward-downward movement of the hull when waves are occurring.

[0005] It is an object of the present invention to provide a marine propulsion system and a method for controlling a marine vessel that prevent an excessive decrease in a vessel speed while a control is performed to adjust the vessel speed based on information regarding upward-downward movement of a hull when waves are occurring. According to the present invention, said object is solved by a marine propulsion system having the features of independent claim 1. Moreover, according to the present invention, said object is solved by a method for controlling a marine vessel having the features of independent claim 19. Preferred embodiments are laid down in the dependent claims.

[0006] A marine propulsion system according to an example embodiment includes a propulsion device configured to be on or in a hull, and a controller configured or programmed to control driving of the propulsion device to adjust a vessel speed, and perform an in-wave vessel speed control to adjust the vessel speed based on information regarding upward-downward movement of the hull. The controller is configured or programmed to perform the in-wave vessel speed control such that the vessel speed becomes equal to or higher than a predetermined minimum vessel speed in an in-wave vessel speed control mode in which the in-wave vessel speed control is performed.

[0007] In a marine propulsion system according to an example embodiment, the controller is configured or programmed to perform the in-wave vessel speed control such that the vessel speed becomes equal to or higher than the predetermined minimum vessel speed in the in-wave vessel speed control mode in which the in-wave vessel speed control is performed. Accordingly, in the in-wave vessel speed control mode, the in-wave vessel speed control is performed while the vessel speed is maintained at the predetermined minimum vessel speed or higher. Consequently, an excessive decrease in the vessel speed is prevented while a control is performed to adjust the vessel speed based on the information regarding upward-downward movement of the hull. In this description, the term "vessel speed" indicates a broader concept including the rotation speed of a drive source (such as an engine) of the propulsion device correlated to a vessel speed, a vessel speed estimated using a global navigation satellite system or a sensor (such as a log speed sensor) installed in a marine vessel, etc.

[0008] In a marine propulsion system according to an example embodiment, the controller is preferably configured or programmed to perform the in-wave vessel speed control such that the vessel speed becomes equal to or higher than the predetermined minimum vessel speed that is set to be equal to or higher than a minimum speed at which the hull is able to plane in the in-wave vessel speed control mode. Accordingly, in the in-wave vessel speed control mode, the in-wave vessel speed control is performed while the vessel speed is maintained at the minimum speed or higher at which the hull is able to plane. Consequently, in the in-wave vessel speed control mode, a resistance of the water to the hull is maintained at a low level by planing the hull, and thus fuel efficiency is improved while the in-wave vessel speed control is being performed. Furthermore, in the in-wave vessel speed control mode, the hull does not change between a non-planing state and a planing state, and thus a decrease in the field of view of a vessel user due to the bow rising when the hull changes from the non-planing state to the planing state is reduced or prevented.

[0009] In a marine propulsion system according to an example embodiment, the controller is preferably configured or programmed to perform a notification control to notify a vessel user that the vessel speed has become the predetermined minimum vessel speed when the vessel speed has become the predetermined minimum vessel speed in the in-wave vessel speed control mode. Accordingly, the vessel user recognizes that the vessel speed has become the minimum vessel speed when the vessel speed has become the minimum vessel speed in the in-wave vessel speed control mode.

[0010] In a marine propulsion system according to an example embodiment, the controller is preferably configured or programmed to perform the in-wave vessel speed control to increase a change in the vessel speed when the vessel speed becomes equal to or lower than a predetermined vessel speed threshold that is greater than the predetermined minimum vessel speed by a predetermined amount in the in-wave vessel speed control mode. Accordingly, when the vessel speed is decreased to the vessel speed threshold or less that is relatively close to the minimum vessel speed in the in-wave vessel speed control mode, a change in the vessel speed in the in-wave vessel speed control is increased, and thus the vessel speed is relatively quickly increased in a situation in which the vessel speed is relatively close to the minimum vessel speed and it is desired to quickly increase the vessel speed in the in-wave vessel speed control mode.

[0011] In a marine propulsion system including the controller configured or programmed to perform the in-wave vessel speed control to increase the change in the vessel speed when the vessel speed becomes equal to or lower than the predetermined vessel speed threshold in the in-wave vessel speed control mode, the controller is preferably configured or programmed to perform the in-wave vessel speed control based on a value obtained by averaging the information regarding upward-downward movement of the hull over a predetermined period of time, and reduce the predetermined period of time during which the averaging is performed to increase the change in the vessel speed when the vessel speed becomes equal to or lower than the predetermined vessel speed threshold in the in-wave vessel speed control mode. Accordingly, the predetermined period of time during which the averaging is performed is reduced, and thus the vessel speed is frequently adjustable by the in-wave vessel speed control. Thus, a structure is easily achieved that allows the vessel speed to be relatively quickly increased in a situation in which the vessel speed is relatively close to the minimum vessel speed and it is desired to quickly increase the vessel speed in the in-wave vessel speed control mode.

[0012] In such a case, the controller is preferably configured or programmed to, in the in-wave vessel speed control mode, change the predetermined period of time during which the averaging is performed to a first period of time so as to increase the change in the vessel speed when the vessel speed becomes equal to or lower than a predetermined first vessel speed threshold, and change the predetermined period of time during which the averaging is performed to a second period of time that is longer than the first period of time when the vessel speed becomes equal to or higher than a predetermined second vessel speed threshold that is greater than the predetermined first vessel speed threshold after becoming equal to or lower than the predetermined first vessel speed threshold. Accordingly, the predetermined period of time during which the averaging is performed is maintained at the relatively short first period of time from when the vessel speed becomes equal to or lower than the first vessel speed threshold until when the vessel speed becomes equal to or higher than the second vessel speed threshold that is greater than the first vessel speed threshold, and thus frequently switching the predetermined period of time during which the averaging is performed between the relatively short first period of time and the relatively long second period of time is reduced or prevented.

[0013] In a marine propulsion system including the controller configured or programmed to perform the in-wave vessel speed control to increase the change in the vessel speed when the vessel speed becomes equal to or lower than the predetermined vessel speed threshold in the in-wave vessel speed control mode, the controller is preferably configured or programmed to perform the in-wave vessel speed control based on a value obtained by averaging the information regarding upward-downward movement of the hull over a predetermined period of time, and change a weighting coefficient to adjust a weighting of the information regarding upward-downward movement of the hull such that a weighting of a latest value of the information regarding upward-downward movement of the hull is greater than a weighting of other than the latest value of the information regarding upward-downward movement of the hull, so as to increase the change in the vessel speed when the vessel speed becomes equal to or lower than the predetermined vessel speed threshold in the in-wave vessel speed control mode. Accordingly, the weighting of the latest value of the information regarding upward-downward movement of the hull is relatively increased, and thus the vessel speed is adjusted while the most recent state of the hull is more reflected in the in-wave vessel speed control. Thus, a structure is easily achieved that allows the vessel speed to be relatively quickly increased in a situation in which the vessel speed is relatively close to the minimum vessel speed and it is desired to quickly increase the vessel speed in the in-wave vessel speed control mode.

[0014] In such a case, the controller is preferably configured or programmed to, in the in-wave vessel speed control mode, change the weighting coefficient to a first weighting value such that the weighting of the latest value of the information regarding upward-downward movement of the hull is greater than the weighting of other than the latest value of the information regarding upward-downward movement of the hull, so as to increase the change in the vessel speed when the vessel speed becomes equal to or lower than a predetermined first vessel speed threshold, and change the weighting coefficient to a second weighting value such that the weighting of the latest value of the information regarding upward-downward movement of the hull is smaller as compared with a case in which the vessel speed is equal to or lower than the predetermined first vessel speed threshold when the vessel speed becomes equal to or higher than a predetermined second vessel speed threshold that is greater than the predetermined first vessel speed threshold after becoming equal to or lower than the predetermined first vessel speed threshold. Accordingly, the weighting coefficient is maintained at the relatively small first weighting value from when the vessel speed becomes equal to or lower than the first vessel speed threshold until when the vessel speed becomes equal to or higher than the second vessel speed threshold that is greater than the first vessel speed threshold, and thus frequently switching the weighting coefficient between the relatively small first weighting value and the relatively large second weighting value is reduced or prevented.

[0015] In a marine propulsion system including the controller configured or programmed to perform the in-wave vessel speed control to increase the change in the vessel speed when the vessel speed becomes equal to or lower than the predetermined vessel speed threshold in the in-wave vessel speed control mode, the controller is preferably configured or programmed to perform the in-wave vessel speed control based on a value obtained by averaging the information regarding upward-downward movement of the hull over a predetermined period of time, and decrease a parameter to be averaged to increase the change in the vessel speed when the vessel speed becomes equal to or lower than the predetermined vessel speed threshold in the in-wave vessel speed control mode. Accordingly, the parameter to be averaged is decreased, and thus the vessel speed is frequently adjusted by the in-wave vessel speed control. Thus, a structure is easily achieved that allows the vessel speed to be relatively quickly increased in a situation in which the vessel speed is relatively close to the minimum vessel speed and it is desired to quickly increase the vessel speed in the in-wave vessel speed control mode.

[0016] In such a case, the controller is preferably configured or programmed to, in the in-wave vessel speed control mode, change the parameter to be averaged to a first parameter value so as to increase the change in the vessel speed when the vessel speed becomes equal to or lower than a predetermined first vessel speed threshold, and change the parameter to be averaged to a second parameter value that is greater than the first parameter value when the vessel speed becomes equal to or higher than a predetermined second vessel speed threshold that is greater than the predetermined first vessel speed threshold after becoming equal to or lower than the predetermined first vessel speed threshold. Accordingly, the parameter to be averaged is maintained at the relatively small first parameter value from when the vessel speed becomes equal to or lower than the first vessel speed threshold until when the vessel speed becomes equal to or higher than the second vessel speed threshold that is greater than the first vessel speed threshold, and thus frequently switching the parameter to be averaged between the relatively small first parameter value and the relatively large second parameter value is reduced or prevented.

[0017] In a marine propulsion system including the controller configured or programmed to perform the in-wave vessel speed control to increase the change in the vessel speed when the vessel speed becomes equal to or lower than the predetermined vessel speed threshold in the in-wave vessel speed control mode, the controller is preferably configured or programmed to increase a maximum value of a rate of change of the vessel speed so as to increase the change in the vessel speed when the vessel speed becomes equal to or lower than the predetermined vessel speed threshold in the in-wave vessel speed control mode. Accordingly, the maximum value of the rate of change of the vessel speed is increased, and thus the rate of change of the vessel speed in the in-wave vessel speed control is increased. Thus, a structure is easily achieved that allows the vessel speed to be relatively quickly increased in a situation in which the vessel speed is relatively close to the minimum vessel speed and it is desired to quickly increase the vessel speed in the in-wave vessel speed control mode.

[0018] In such a case, the controller is preferably configured or programmed to, in the in-wave vessel speed control mode, change the maximum value of the rate of change of the vessel speed to a first maximum value of the rate of change so as to increase the change in the vessel speed when the vessel speed becomes equal to or lower than a predetermined first vessel speed threshold, and change the maximum value of the rate of change of the vessel speed to a second maximum value of the rate of change that is smaller than the first maximum value of the rate of change when the vessel speed becomes equal to or higher than a predetermined second vessel speed threshold that is greater than the predetermined first vessel speed threshold after becoming equal to or lower than the predetermined first vessel speed threshold. Accordingly, the maximum value of the rate of change of the vessel speed is maintained at the relatively small first maximum value of the rate of change from when the vessel speed becomes equal to or lower than the first vessel speed threshold until when the vessel speed becomes equal to or higher than the second vessel speed threshold that is greater than the first vessel speed threshold, and thus frequently switching the maximum value of the rate of change of the vessel speed between the relatively small first maximum value of the rate of change and the relatively large second maximum value of the rate of change is reduced or prevented.

[0019] In a marine propulsion system according to an example embodiment, the controller is preferably configured or programmed to perform the in-wave vessel speed control based on a moving average value obtained by averaging the information regarding upward-downward movement of the hull over a predetermined period of time. Accordingly, unlike a case in which the in-wave vessel speed control is performed based on an averaged value that is not a moving average value, the in-wave vessel speed control is accurately performed based on the information regarding upward-downward movement of the hull that reflects the state of the hull that changes from moment to moment.

[0020] A marine propulsion system including the controller configured or programmed to perform the notification control preferably further includes an operator configured to receive an operation from the vessel user, and the controller is preferably configured or programmed to, in the in-wave vessel speed control mode, perform the notification control when the vessel speed has become the predetermined minimum vessel speed, and change the predetermined minimum vessel speed when the vessel user operates the operator to change the predetermined minimum vessel speed. Accordingly, when the vessel user who has recognized that the vessel speed has become the minimum vessel speed due to the notification control wants to temporarily change the minimum vessel speed, the vessel user changes the minimum vessel speed by operating the operator to change the minimum vessel speed.

[0021] In a marine propulsion system including the controller configured or programmed to change the predetermined minimum vessel speed when the vessel user operates the operator to change the predetermined minimum vessel speed in the in-wave vessel speed control mode, the controller is preferably configured or programmed to, in the in-wave vessel speed control mode, perform the notification control when the vessel speed has become the predetermined minimum vessel speed, and increase the predetermined minimum vessel speed when the vessel user operates the operator to increase the predetermined minimum vessel speed. Accordingly, when the vessel user who has recognized that the vessel speed has become the minimum vessel speed due to the notification control wants to temporarily increase the minimum vessel speed, the vessel user increases the minimum vessel speed by operating the operator to increase the minimum vessel speed.

[0022] The above and other elements, features, steps, characteristics and advantages of preferred embodiments will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 

FIG. 1 is a block diagram of a marine propulsion system according to an example embodiment.

FIG. 2 is a schematic view of a marine vessel according to an example embodiment.

FIG. 3 is a side view showing a propulsion device of a marine propulsion system according to an example embodiment.

FIG. 4 is a diagram showing changes in a vessel speed by an in-wave vessel speed control in a marine propulsion system according to an example embodiment.

FIG. 5 is a diagram illustrating vessel speed adjustment during an in-wave vessel speed control in a marine propulsion system according to an example embodiment.

FIG. 6 is a diagram showing a minimum vessel speed and a vessel speed threshold during an in-wave vessel speed control in a marine propulsion system according to an example embodiment.

FIG. 7 is a diagram illustrating a first method for increasing a change in a vessel speed during an in-wave vessel speed control in a marine propulsion system according to an example embodiment.

FIG. 8 is a diagram illustrating a second method for increasing a change in a vessel speed during an in-wave vessel speed control in a marine propulsion system according to an example embodiment.

FIG. 9 is a diagram illustrating a third method for increasing a change in a vessel speed during an in-wave vessel speed control in a marine propulsion system according to an example embodiment.

FIG. 10 is a diagram illustrating a fourth method for increasing a change in a vessel speed during an in-wave vessel speed control in a marine propulsion system according to an example embodiment.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

[0024] Example embodiments are hereinafter described with reference to the drawings.

[0025] A marine propulsion system 100 and a marine vessel 110 according to example embodiments are now described with reference to FIGS. 1 to 10.

[0026] As shown in FIG. 1, the marine propulsion system 100 is provided on or in the marine vessel 110. The marine propulsion system 100 propels the marine vessel 110. The marine vessel 110 may be a relatively small marine vessel used for sightseeing or fishing, for example.

[0027] The marine propulsion system 100 (marine vessel 110) includes a hull 10 and a propulsion device 20. As shown in FIG. 2, the propulsion device 20 is provided on the hull 10. Only one propulsion device 20 is attached to a stern 11 of the hull 10. That is, the propulsion device 20 is an outboard motor.

[0028] As shown in FIG. 1, the hull 10 includes an operator 13, a controller 14, a display 15, an inertial measurement unit (IMU) 16, and a global navigation satellite system (GNSS) communicator 17.

[0029] The operator 13 receives operations from a vessel user to operate (maneuver) the marine vessel 110. The operator 13 includes a remote control and a steering wheel.

[0030] The controller 14 controls an engine control unit (ECU) 28 and a steering control unit (SCU) 29 of the propulsion device 20 based on operations performed on the operator 13. That is, the controller 14 controls driving of the propulsion device 20 to adjust a vessel speed V (see FIG. 4). The controller 14 is a computer that includes an arithmetic unit such as a central processing unit (CPU), storages such as a read-only memory (ROM) and a random access memory (RAM), etc.

[0031] The display 15 displays information on the marine vessel 110. The information on the marine vessel 110 includes the vessel speed V (actual vessel speed) (see FIG. 5), the rotation speed of an engine 22 of the propulsion device 20, the shift state of the propulsion device 20, and a navigation mode of the marine vessel 110, for example. The navigation mode of the marine vessel 110 includes an in-wave vessel speed control mode described below. The display 15 is a liquid crystal display, for example. The display 15 may be a touch panel to display buttons that receive operations from the vessel user.

[0032] The IMU 16 includes a gyroscope, an accelerometer, etc. The IMU 16 detects an acceleration of the hull 10 in an upward-downward direction, for example. That is, the IMU 16 detects information la regarding upward-downward movement of the hull 10. The controller 14 acquires the information la regarding upward-downward movement of the hull 10 detected by the IMU 16.

[0033] A global navigation satellite system 120 includes the GNSS communicator 17 and a GNSS satellite 121. The GNSS communicator 17 communicates with the GNSS satellite 121. The controller 14 acquires position information about the hull 10, the vessel speed V (actual vessel speed) (see FIG. 5), etc. based on information communicated with the GNSS satellite 121 via the GNSS communicator 17.

[0034] As shown in FIG. 3, the propulsion device 20 includes a propulsion device main body 20a and a bracket 20b. The propulsion device main body 20a is attached to a transom 12 at the stern 11 of the hull 10 via the bracket 20b.

[0035] The propulsion device 20 includes the engine 22 to drive a propeller 21 to generate a thrust. That is, the propulsion device 20 is an engine outboard motor including the engine 22 to drive the propeller 21. Specifically, the propulsion device main body 20a includes the engine 22, a drive shaft 23, a gearing 24, a propeller shaft 25, and the propeller 21. The engine 22 is an internal combustion engine that generates a driving force. The driving force of the engine 22 is transmitted to the propeller 21 via the drive shaft 23, the gearing 24, and the propeller shaft 25. The propeller 21 generates a propulsive force to propel the hull 10 by rotating in the water by the driving force transmitted from the engine 22.

[0036] The propulsion device main body 20a includes a shift actuator 26 to switch the shift state of the propulsion device 20. The shift actuator 26 switches the shift state of the propulsion device 20 between a forward movement state, a reverse movement state, and a neutral state by switching the meshing of the gearing 24. In the forward movement state, a driving force is transmitted from the engine 22 to the propeller 21 to generate a forward thrust from the propeller 21. In the reverse movement state, a driving force is transmitted from the engine 22 to the propeller 21 to generate a reverse thrust from the propeller 21. In the neutral state, a driving force is not transmitted from the engine 22 to the propeller 21 to not generate a thrust from the propeller 21.

[0037] The propulsion device 20 includes a steering 27 to change the direction of the propulsive force of the propeller 21 so as to change the traveling direction of the hull 10. Specifically, the steering 27 is provided on the bracket 20b. The steering 27 includes a steering shaft 27a that extends in the upward-downward direction. The propulsion device main body 20a is rotated in a right-left direction by the steering 27 about the steering shaft 27a with respect to the bracket 20b. When the propulsion device main body 20a rotates in the right-left direction about the steering shaft 27a, the orientation of the propeller 21 also rotates in the right-left direction. Thus, the direction of the propulsive force of the propeller 21 is changed. That is, the propulsion device 20 is steered.

[0038] As shown in FIG. 1, the propulsion device 20 includes the ECU 28 and the SCU 29. The ECU 28 controls driving of the engine 22 and driving of the shift actuator 26 based on control by the controller 14. That is, the controller 14 controls the vessel speed V (see FIG. 4) by controlling driving of the engine 22 via the ECU 28 to change the propulsive force of the propeller 21. The SCU 29 controls driving of the steering 27 based on control by the controller 14. Each of the ECU 28 and the SCU 29 is a computer that includes an arithmetic unit such as a CPU, storages such as a ROM and a RAM, etc.

[0039] As shown in FIG. 4, the marine propulsion system 100 (see FIG. 1) (marine vessel 110 (see FIG. 1)) adjusts the vessel speed V such that an impact on the hull 10 caused by the hull 10 (see FIG. 1) riding over a wave is within a preset range when waves are occurring. Specifically, the controller 14 (see FIG. 1) performs an in-wave vessel speed control to adjust the vessel speed V based on the information Ia (see FIG. 1) regarding upward-downward movement of the hull 10 when waves are occurring. The information Ia regarding upward-downward movement of the hull 10 refers to the acceleration of the hull 10 in the upward-downward direction, for example.

[0040] Specifically, as shown in FIG. 5, the controller 14 (see FIG. 1) first acquires the information Ia regarding upward-downward movement of the hull 10 from the IMU 16 (see FIG. 1). The controller 14 then calculates a target vessel speed VT, which is a target value of the vessel speed V, based on the acquired information Ia regarding upward-downward movement of the hull 10, the vessel speed V (actual vessel speed) acquired by the global navigation satellite system 120 (see FIG. 1), and information Ib to maintain the impact on the hull 10 within the preset range. Then, the controller 14 performs a feedback control to adjust the vessel speed V based on a difference between the calculated target vessel speed VT and the acquired vessel speed V (actual vessel speed).

[0041] The controller 14 (see FIG. 1) performs the in-wave vessel speed control based on a moving average value obtained by averaging the information Ia regarding upward-downward movement of the hull 10 over a predetermined period of time P. Specifically, the controller 14 (see FIG. 1) calculates the target vessel speed VT such that the impact on the hull 10 caused by the hull 10 riding over a wave is within the preset range when waves are occurring, based on the moving average value obtained by averaging the acquired information Ia regarding upward-downward movement of the hull 10 over the predetermined period of time P, a moving average value obtained by averaging the vessel speed V (actual vessel speed) over the predetermined period of time P, and the information Ib to maintain the impact on the hull 10 within the preset range.

[0042] As shown in FIG. 4, when the navigation mode of the marine vessel 110 (see FIG. 1) is the in-wave vessel speed control mode in which an in-wave vessel speed control is performed, the controller 14 (see FIG. 1) performs the in-wave vessel speed control. The controller 14 changes the navigation mode of the marine vessel 110 to the in-wave vessel speed control mode when the vessel user operates the operator 13 to change the navigation mode of the marine vessel 110 to the in-wave vessel speed control mode.

[0043] In FIG. 4, a state in which the navigation mode of the marine vessel 110 is the in-wave vessel speed control mode and a state in which the navigation mode is not the in-wave vessel speed control mode are defined as an ON in-wave vessel speed control mode and an OFF in-wave vessel speed control mode, respectively.

[0044] As shown in FIG. 6, the controller 14 (see FIG. 1) performs the in-wave vessel speed control such that the vessel speed V becomes equal to or higher than a predetermined minimum vessel speed V0 in the in-wave vessel speed control mode. The predetermined minimum vessel speed V0 is set to be equal to or higher than a minimum speed at which the hull 10 (see FIG. 1) is able to plane. That is, the controller 14 performs the in-wave vessel speed control such that the vessel speed V becomes equal to or higher than the minimum vessel speed V0, which is set to be equal to or higher than the minimum speed at which the hull 10 is able to plane.

[0045] The controller 14 (see FIG. 1) performs the in-wave vessel speed control using the following four methods to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than a predetermined vessel speed threshold VP that is greater than the minimum vessel speed V0 by a predetermined amount in the in-wave vessel speed control mode.

[0046] As shown in FIG. 7, as a first method for increasing a change in the vessel speed V during the in-wave vessel speed control, the controller 14 (see FIG. 1) reduces the predetermined period of time P during which the averaging is performed to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the vessel speed threshold VP (see FIG. 6) in the in-wave vessel speed control mode. Furthermore, control hysteresis is set in a control to change the predetermined period of time P during which the controller 14 performs the averaging.

[0047] Specifically, the controller 14 (see FIG. 1) first determines whether or not the vessel speed V has become equal to or lower than a predetermined first vessel speed threshold VP1 in the in-wave vessel speed control mode (step S11). When determining that the vessel speed V has become equal to or lower than the predetermined first vessel speed threshold VP1, the controller 14 changes the predetermined period of time P during which the averaging is performed to a first period of time P1 so as to increase a change in the vessel speed V (step S12). The controller 14 repeats the process operation in step S11 until it determines that the vessel speed V has become equal to or lower than the predetermined first vessel speed threshold VP1. It is assumed that at the time of step S11, the vessel speed V is equal to or higher than a predetermined second vessel speed threshold VP2 described below.

[0048] Then, the controller 14 (see FIG. 1) determines whether or not the vessel speed V has become equal to or higher than the predetermined second vessel speed threshold VP2 that is greater than the first vessel speed threshold VP1 after becoming equal to or lower than the first vessel speed threshold VP1 in the in-wave vessel speed control mode (step S13). When determining that the vessel speed V has become equal to or higher than the second vessel speed threshold VP2 after becoming equal to or lower than the first vessel speed threshold VP1, the controller 14 changes the predetermined period of time P during which the averaging is performed to a second period of time P2 that is longer than the first period of time P1 (step S14). The controller 14 repeats the process operation in step S13 until it determines that the vessel speed V has become equal to or higher than the second vessel speed threshold VP2. After step S14, the controller 14 returns to step S11.

[0049] As shown in FIG. 8, as a second method for increasing a change in the vessel speed V during the in-wave vessel speed control, the controller 14 (see FIG. 1) changes a weighting coefficient K to adjust the weighting of the information Ia regarding upward-downward movement of the hull 10 such that the weighting of the latest value Ian of the information Ia regarding upward-downward movement of the hull 10 is greater than the weighting of other than the latest value Ian of the information Ia regarding upward-downward movement of the hull 10, so as to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the vessel speed threshold VP (see FIG. 6) in the in-wave vessel speed control mode. Control hysteresis is set in a control to change the weighting coefficient K to adjust the weighting of the information Ia regarding upward-downward movement of the hull 10.

[0050] Specifically, the controller 14 (see FIG. 1) first determines whether or not the vessel speed V has become equal to or lower than the predetermined first vessel speed threshold VP1 in the in-wave vessel speed control mode (step S21). When determining that the vessel speed V has become equal to or lower than the predetermined first vessel speed threshold VP1, the controller 14 changes the weighting coefficient K to a first weighting value K1 such that the weighting of the latest value Ian of the information Ia regarding upward-downward movement of the hull 10 is greater than the weighting of other than the latest value Ian of the information Ia regarding upward-downward movement of the hull 10, so as to increase a change in the vessel speed V (step S22). The controller 14 repeats the process operation in step S21 until it determines that the vessel speed V has become equal to or lower than the predetermined first vessel speed threshold VP1. It is assumed that at the time of step S21, the vessel speed V is equal to or higher than the predetermined second vessel speed threshold VP2.

[0051] Then, the controller 14 (see FIG. 1) determines whether or not the vessel speed V has become equal to or higher than the predetermined second vessel speed threshold VP2 that is greater than the first vessel speed threshold VP1 after becoming equal to or lower than the first vessel speed threshold VP1 in the in-wave vessel speed control mode (step S23). When determining that the vessel speed V has become equal to or higher than the second vessel speed threshold VP2 after becoming equal to or lower than the first vessel speed threshold VP1, the controller 14 changes the weighting coefficient K to a second weighting value K2 such that the weighting of the latest value Ian of the information Ia regarding upward-downward movement of the hull 10 is smaller as compared with a case in which the vessel speed V is equal to or lower than the first vessel speed threshold VP1 (step S24). The controller 14 repeats the process operation in step S23 until it determines that the vessel speed V has become equal to or higher than the second vessel speed threshold VP2. After step S24, the controller 14 returns to step S21.

[0052] As shown in FIG. 9, as a third method for increasing a change in the vessel speed V during the in-wave vessel speed control, the controller 14 (see FIG. 1) decreases a parameter N to be averaged to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the vessel speed threshold VP (see FIG. 6) in the in-wave vessel speed control mode. Control hysteresis is set in a control to change the parameter N to be averaged.

[0053] Specifically, the controller 14 (see FIG. 1) first determines whether or not the vessel speed V has become equal to or lower than the predetermined first vessel speed threshold VP1 in the in-wave vessel speed control mode (step S31). When determining that the vessel speed V has become equal to or lower than the predetermined first vessel speed threshold VP1, the controller 14 changes the parameter N to be averaged to a first parameter value N1 so as to increase a change in the vessel speed V (step S32). The controller 14 repeats the process operation in step S31 until it determines that the vessel speed V has become equal to or lower than the predetermined first vessel speed threshold VP1. It is assumed that at the time of step S31, the vessel speed V is equal to or higher than the predetermined second vessel speed threshold VP2.

[0054] Then, the controller 14 (see FIG. 1) determines whether or not the vessel speed V has become equal to or higher than the predetermined second vessel speed threshold VP2 that is greater than the first vessel speed threshold VP1 after becoming equal to or lower than the first vessel speed threshold VP1 in the in-wave vessel speed control mode (step S33). When determining that the vessel speed V has become equal to or higher than the second vessel speed threshold VP2 after becoming equal to or lower than the first vessel speed threshold VP1, the controller 14 changes the parameter N to be averaged to a second parameter value N2 that is greater than the first parameter value N1 (step S34). The controller 14 repeats the process operation in step S33 until it determines that the vessel speed V has become equal to or higher than the second vessel speed threshold VP2. After step S34, the controller 14 returns to step S31.

[0055] As shown in FIG. 10, as a fourth method for increasing a change in the vessel speed V during the in-wave vessel speed control, the controller 14 (see FIG. 1) increases a maximum value MM of the rate of change M of the vessel speed V so as to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the vessel speed threshold VP (see FIG. 6) in the in-wave vessel speed control mode. Control hysteresis is set in a control to change the maximum value MM of the rate of change M of the vessel speed V.

[0056] Specifically, the controller 14 (see FIG. 1) first determines whether or not the vessel speed V has become equal to or lower than the predetermined first vessel speed threshold VP1 in the in-wave vessel speed control mode (step S41). When determining that the vessel speed V has become equal to or lower than the predetermined first vessel speed threshold VP1, the controller 14 changes the maximum value MM of the rate of change M of the vessel speed V to a first maximum value MM1 of the rate of change so as to increase a change in the vessel speed V (step S42). The controller 14 repeats the process operation in step S41 until it determines that the vessel speed V has become equal to or lower than the predetermined first vessel speed threshold VP1. It is assumed that at the time of step S41, the vessel speed V is equal to or higher than the predetermined second vessel speed threshold VP2.

[0057] Then, the controller 14 (see FIG. 1) determines whether or not the vessel speed V has become equal to or higher than the predetermined second vessel speed threshold VP2 that is greater than the first vessel speed threshold VP1 after becoming equal to or lower than the first vessel speed threshold VP1 in the in-wave vessel speed control mode (step S43). When determining that the vessel speed V has become equal to or higher than the second vessel speed threshold VP2 after becoming equal to or lower than the first vessel speed threshold VP1, the controller 14 changes the maximum value MM of the rate of change M of the vessel speed V to a second maximum value MM2 of the rate of change that is smaller than the first maximum value MM1 of the rate of change (step S44). The controller 14 repeats the process operation in step S43 until it determines that the vessel speed V has become equal to or higher than the second vessel speed threshold VP2. After step S44, the controller 14 returns to step S41.

[0058] As shown in FIG. 6, the controller 14 (see FIG. 1) performs a notification control to notify the vessel user that the vessel speed V has become the minimum vessel speed V0 when the vessel speed V has become the minimum vessel speed V0 in the in-wave vessel speed control mode. For example, the controller 14 performs a notification control such as a control to display, on the display 15 (see FIG. 1) as a notification means, a message and a mark indicating that the vessel speed V has become the minimum vessel speed V0, a control to output a sound (with a related notification means) indicating that the vessel speed V has become the minimum vessel speed V0, or a control to light or flash a lamp as a notification means indicating that the vessel speed V has become the minimum vessel speed V0 when the vessel speed V has become the minimum vessel speed V0.

[0059] In the in-wave vessel speed control mode, the controller 14 (see Fig. 1) performs the notification control when the vessel speed V has become the minimum vessel speed V0, and changes the minimum vessel speed V0 when the vessel user operates the operator 13 (see FIG. 1) to change the minimum vessel speed V0. Specifically, in the in-wave vessel speed control mode, the controller 14 (see FIG. 1) performs the notification control when the vessel speed V has become the minimum vessel speed V0, and increases the minimum vessel speed V0 when the vessel user operates the operator 13 to increase the minimum vessel speed V0. The controller 14 returns the changed minimum vessel speed V0 to an initial value when the controller 14 is powered off or restarted.

[0060] According to the various example embodiments described above, the following advantageous effects are achieved.

[0061] According to an example embodiment, the controller 14 is configured or programmed to perform an in-wave vessel speed control such that the vessel speed V becomes equal to or higher than the predetermined minimum vessel speed V0 in the in-wave vessel speed control mode in which the in-wave vessel speed control is performed. Accordingly, in the in-wave vessel speed control mode, the in-wave vessel speed control is performed while the vessel speed V is maintained at the predetermined minimum vessel speed V0 or higher. Consequently, an excessive decrease in the vessel speed V is prevented while a control is performed to adjust the vessel speed V based on the information Ia regarding upward-downward movement of the hull 10 when waves are occurring.

[0062] According to an example embodiment, the controller 14 is configured or programmed to perform the in-wave vessel speed control such that the vessel speed V becomes equal to or higher than the minimum vessel speed V0 that is set to be equal to or higher than the minimum speed at which the hull 10 is able to plane in the in-wave vessel speed control mode. Accordingly, in the in-wave vessel speed control mode, the in-wave vessel speed control is performed while the vessel speed V is maintained at the minimum speed or higher at which the hull 10 is able to plane. Consequently, in the in-wave vessel speed control mode, a resistance of the water to the hull 10 is maintained at a low level by planing the hull 10, and thus fuel efficiency is improved while the in-wave vessel speed control is being performed. Furthermore, the hull 10 does not change between a non-planing state and a planing state, and thus a decrease in the field of view of the vessel user due to the bow rising when the hull 10 changes from the non-planing state to the planing state is reduced or prevented.

[0063] According to an example embodiment, the controller 14 is configured or programmed to perform the notification control to notify the vessel user that the vessel speed V has become the minimum vessel speed V0 when the vessel speed V has become the minimum vessel speed V0 in the in-wave vessel speed control mode. Accordingly, the vessel user recognizes that the vessel speed V has become the minimum vessel speed V0 when the vessel speed V has become the minimum vessel speed V0 in the in-wave vessel speed control mode.

[0064] According to an example embodiment, the controller 14 is configured or programmed to perform the in-wave vessel speed control to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the predetermined vessel speed threshold VP that is greater than the minimum vessel speed V0 by the predetermined amount in the in-wave vessel speed control mode. Accordingly, when the vessel speed V is decreased to the vessel speed threshold VP or less that is relatively close to the minimum vessel speed V0 in the in-wave vessel speed control mode, a change in the vessel speed V in the in-wave vessel speed control is increased, and thus the vessel speed V is relatively quickly increased in a situation in which the vessel speed V is relatively close to the minimum vessel speed V0 and it is desired to quickly increase the vessel speed V in the in-wave vessel speed control mode.

[0065] According to an example embodiment, the controller 14 is configured or programmed to perform the in-wave vessel speed control based on a value obtained by averaging the information Ia regarding upward-downward movement of the hull 10 over the predetermined period of time P. Furthermore, the controller 14 is configured or programmed to reduce the predetermined period of time P during which the averaging is performed to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the vessel speed threshold VP in the in-wave vessel speed control mode. Accordingly, the predetermined period of time P during which the averaging is performed is reduced, and thus the vessel speed V is frequently adjustable by the in-wave vessel speed control. Thus, a structure is easily achieved that allows the vessel speed V to be relatively quickly increased in a situation in which the vessel speed V is relatively close to the minimum vessel speed V0 and it is desired to quickly increase the vessel speed V in the in-wave vessel speed control mode.

[0066] According to an example embodiment, the controller 14 is configured or programmed to, in the in-wave vessel speed control mode, change the predetermined period of time P during which the averaging is performed to the first period of time P1 so as to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the predetermined first vessel speed threshold VP1, and change the predetermined period of time P during which the averaging is performed to the second period of time P2 that is longer than the first period of time P1 when the vessel speed V becomes equal to or higher than the predetermined second vessel speed threshold VP2 that is greater than the first vessel speed threshold VP1 after becoming equal to or lower than the first vessel speed threshold VP1. Accordingly, the predetermined period of time P during which the averaging is performed is maintained at the relatively short first period of time P1 from when the vessel speed V becomes equal to or lower than the first vessel speed threshold VP1 until when the vessel speed V becomes equal to or higher than the second vessel speed threshold VP2 that is greater than the first vessel speed threshold VP1, and thus frequently switching the predetermined period of time P during which the averaging is performed between the relatively short first period of time P1 and the relatively long second period of time P2 is reduced or prevented.

[0067] According to an example embodiment, the controller 14 is configured or programmed to perform the in-wave vessel speed control based on the value obtained by averaging the information Ia regarding upward-downward movement of the hull 10 over the predetermined period of time P. Furthermore, the controller 14 is configured or programmed to change the weighting coefficient K to adjust the weighting of the information Ia regarding upward-downward movement of the hull 10 such that the weighting of the latest value Ian of the information Ia regarding upward-downward movement of the hull 10 is greater than the weighting of other than the latest value Ian of the information Ia regarding upward-downward movement of the hull 10, so as to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the vessel speed threshold VP in the in-wave vessel speed control mode. Accordingly, the weighting of the latest value Ian of the information Ia regarding upward-downward movement of the hull 10 is relatively increased, and thus the vessel speed V is adjusted while the most recent state of the hull 10 is more reflected in the in-wave vessel speed control. Thus, a structure is easily achieved that allows the vessel speed V to be relatively quickly increased in a situation in which the vessel speed V is relatively close to the minimum vessel speed V0 and it is desired to quickly increase the vessel speed V in the in-wave vessel speed control mode.

[0068] According to an example embodiment, the controller 14 is configured or programmed to, in the in-wave vessel speed control mode, change the weighting coefficient K to the first weighting value K1 such that the weighting of the latest value Ian of the information Ia regarding upward-downward movement of the hull 10 is greater than the weighting of other than the latest value Ian of the information Ia regarding upward-downward movement of the hull 10, so as to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the predetermined first vessel speed threshold VP1, and change the weighting coefficient K to the second weighting value K2 such that the weighting of the latest value Ian of the information Ia regarding upward-downward movement of the hull 10 is smaller as compared with a case in which the vessel speed V is equal to or lower than the first vessel speed threshold VP1 when the vessel speed V becomes equal to or higher than the predetermined second vessel speed threshold VP2 that is greater than the first vessel speed threshold VP1 after becoming equal to or lower than the first vessel speed threshold VP1. Accordingly, the weighting coefficient K is maintained at the relatively small first weighting value K1 from when the vessel speed V becomes equal to or lower than the first vessel speed threshold VP1 until when the vessel speed V becomes equal to or higher than the second vessel speed threshold VP2 that is greater than the first vessel speed threshold VP1, and thus frequently switching the weighting coefficient K between the relatively small first weighting value K1 and the relatively large second weighting value K2 is reduced or prevented.

[0069] According to an example embodiment, the controller 14 is configured or programmed to perform the in-wave vessel speed control based on the value obtained by averaging the information Ia regarding upward-downward movement of the hull 10 over the predetermined period of time P. Furthermore, the controller 14 is configured or programmed to decrease the parameter N to be averaged to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the vessel speed threshold VP in the in-wave vessel speed control mode. Accordingly, the parameter N to be averaged is decreased, and thus the vessel speed V is frequently adjusted by the in-wave vessel speed control. Thus, a structure is easily achieved that allows the vessel speed V to be relatively quickly increased in a situation in which the vessel speed V is relatively close to the minimum vessel speed V0 and it is desired to quickly increase the vessel speed V in the in-wave vessel speed control mode.

[0070] According to an example embodiment, the controller 14 is configured or programmed to, in the in-wave vessel speed control mode, change the parameter N to be averaged to the first parameter value N1 so as to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the predetermined first vessel speed threshold VP1, and change the parameter N to be averaged to the second parameter value N2 that is greater than the first parameter value N1 when the vessel speed V becomes equal to or higher than the predetermined second vessel speed threshold VP2 that is greater than the first vessel speed threshold VP1 after becoming equal to or lower than the first vessel speed threshold VP1. Accordingly, the parameter N to be averaged is maintained at the relatively small first parameter value N1 from when the vessel speed V becomes equal to or lower than the first vessel speed threshold VP1 until when the vessel speed V becomes equal to or higher than the second vessel speed threshold VP2 that is greater than the first vessel speed threshold VP1, and thus frequently switching the parameter N to be averaged between the relatively small first parameter value N1 and the relatively large second parameter value N2 is reduced or prevented.

[0071] According to an example embodiment, the controller 14 is configured or programmed to increase the maximum value MM of the rate of change M of the vessel speed V so as to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the vessel speed threshold VP in the in-wave vessel speed control mode. Accordingly, the maximum value MM of the rate of change M of the vessel speed V is increased, and thus the rate of change of the vessel speed V in the in-wave vessel speed control is increased. Thus, a structure is easily achieved that allows the vessel speed V to be relatively quickly increased in a situation in which the vessel speed V is relatively close to the minimum vessel speed V0 and it is desired to quickly increase the vessel speed V in the in-wave vessel speed control mode.

[0072] According to an example embodiment, the controller 14 is configured or programmed to, in the in-wave vessel speed control mode, change the maximum value MM of the rate of change M of the vessel speed V to the first maximum value MM1 of the rate of change so as to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the predetermined first vessel speed threshold VP1, and change the maximum value MM of the rate of change M of the vessel speed V to the second maximum value MM2 of the rate of change that is smaller than the first maximum value MM1 of the rate of change when the vessel speed V becomes equal to or higher than the predetermined second vessel speed threshold VP2 that is greater than the first vessel speed threshold VP1 after becoming equal to or lower than the first vessel speed threshold VP1. Accordingly, the maximum value MM of the rate of change M of the vessel speed V is maintained at the relatively small first maximum value MM1 of the rate of change from when the vessel speed V becomes equal to or lower than the first vessel speed threshold VP1 until when the vessel speed V becomes equal to or higher than the second vessel speed threshold VP2 that is greater than the first vessel speed threshold VP1, and thus frequently switching the maximum value MM of the rate of change M of the vessel speed V between the relatively small first maximum value MM1 of the rate of change and the relatively large second maximum value MM2 of the rate of change is reduced or prevented.

[0073] According to an example embodiment, the controller 14 is configured or programmed to perform the in-wave vessel speed control based on the moving average value obtained by averaging the information Ia regarding upward-downward movement of the hull 10 over the predetermined period of time P. Accordingly, unlike a case in which the in-wave vessel speed control is performed based on an averaged value that is not a moving average value, the in-wave vessel speed control is accurately performed based on the information Ia regarding upward-downward movement of the hull 10 that reflects the state of the hull 10 that changes from moment to moment.

[0074] According to an example embodiment, the marine propulsion system 100 (marine vessel 110) includes the operator 13 to receive operations from the vessel user. Furthermore, the controller 14 is configured or programmed to, in the in-wave vessel speed control mode, perform the notification control when the vessel speed V has become the minimum vessel speed V0, and change the minimum vessel speed V0 when the vessel user operates the operator 13 to change the minimum vessel speed V0. Accordingly, when the vessel user who has recognized that the vessel speed V has become the minimum vessel speed V0 due to the notification control wants to temporarily change the minimum vessel speed V0, the vessel user changes the minimum vessel speed V0 by operating the operator 13 to change the minimum vessel speed V0.

[0075] According to an example embodiment, the controller 14 is configured or programmed to, in the in-wave vessel speed control mode, perform the notification control when the vessel speed V has become the minimum vessel speed V0, and increase the minimum vessel speed V0 when the vessel user operates the operator 13 to increase the minimum vessel speed V0. Accordingly, when the vessel user who has recognized that the vessel speed V has become the minimum vessel speed V0 due to the notification control wants to temporarily increase the minimum vessel speed V0, the vessel user increases the minimum vessel speed V0 by operating the operator 13 to increase the minimum vessel speed V0.

[0076] According to an example embodiment, the controller 14 is configured or programmed to return the changed minimum vessel speed V0 to the initial value when the controller 14 is powered off or restarted in the in-wave vessel speed control mode. Accordingly, a state in which the minimum vessel speed V0 has been changed is prevented from remaining unchanged.

[0077] The example embodiments described above are illustrative for present teaching but the present teaching also relates to modifications of the example embodiments.

[0078] For example, the controller 14 preferably returns the changed minimum vessel speed V0 to the initial value when the controller 14 is powered off or restarted in the in-wave vessel speed control mode in example embodiments described above. Alternatively, in the present teaching, the controller may return the changed minimum vessel speed to the initial value when the vessel user operates the operator to return the changed minimum vessel speed to the initial value in the in-wave vessel speed control mode.

[0079] In the in-wave vessel speed control mode, the controller 14 preferably performs the notification control when the vessel speed V has become the minimum vessel speed V0, and increases the minimum vessel speed V0 when the vessel user operates the operator 13 to increase the minimum vessel speed V0 in example embodiments described above. Alternatively, in the present teaching, in the in-wave vessel speed control mode, the controller may perform the notification control when the vessel speed has become the minimum vessel speed, and decrease the minimum vessel speed when the vessel user operates the operator 13 to decrease the minimum vessel speed.

[0080] In the in-wave vessel speed control mode, the controller 14 preferably performs the notification control when the vessel speed V has become the minimum vessel speed V0, and changes the minimum vessel speed V0 when the vessel user operates the operator 13 to change the minimum vessel speed V0 in example embodiments described above. Alternatively, in the present teaching, in the in-wave vessel speed control mode, the controller may perform the notification control when the vessel speed has become the minimum vessel speed, but may not change the minimum vessel speed. Furthermore, in the in-wave vessel speed control mode, the controller may alternatively perform the notification control when the vessel speed has become the minimum vessel speed, and invalidate the minimum vessel speed when the vessel user operates the operator to invalidate the minimum vessel speed.

[0081] The controller 14 preferably performs the in-wave vessel speed control based on the moving average value obtained by averaging the information Ia regarding upward-downward movement of the hull 10 over the predetermined period of time P in example embodiments described above. Alternatively, in the present teaching, the controller may perform the in-wave vessel speed control based on a value obtained by averaging the information regarding upward-downward movement of the hull other than the moving average value.

[0082] In the in-wave vessel speed control mode, the controller 14 preferably changes the maximum value MM of the rate of change M of the vessel speed V to the first maximum value MM1 of the rate of change so as to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the predetermined first vessel speed threshold VP1, and changes the maximum value MM of the rate of change M of the vessel speed V to the second maximum value MM2 of the rate of change that is smaller than the first maximum value MM1 of the rate of change when the vessel speed V becomes equal to or higher than the predetermined second vessel speed threshold VP2 that is greater than the first vessel speed threshold VP1 after becoming equal to or lower than the first vessel speed threshold VP1 in example embodiments described above. Alternatively, in the present teaching, in the in-wave vessel speed control mode, the controller may change the maximum value of the rate of change of the vessel speed to the first maximum value of the rate of change so as to increase a change in the vessel speed when the vessel speed becomes equal to or lower than the predetermined first vessel speed threshold, and change the maximum value of the rate of change of the vessel speed to the second maximum value of the rate of change that is smaller than the first maximum value of the rate of change when the vessel speed becomes higher than the first vessel speed threshold after becoming equal to or lower than the first vessel speed threshold. That is, in a control to change the maximum value of the rate of change of the vessel speed, control hysteresis may not be set.

[0083] The controller 14 preferably increases the maximum value MM of the rate of change M of the vessel speed V so as to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the vessel speed threshold VP in the in-wave vessel speed control mode in example embodiments described above. Alternatively, in the present teaching, the controller may not increase the maximum value of the rate of change of the vessel speed even when the vessel speed becomes equal to or lower than the vessel speed threshold in the in-wave vessel speed control mode.

[0084] In the in-wave vessel speed control mode, the controller 14 preferably changes the parameter N to be averaged to the first parameter value N1 so as to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the predetermined first vessel speed threshold VP1, and changes the parameter N to be averaged to the second parameter value N2 that is greater than the first parameter value N1 when the vessel speed V becomes equal to or higher than the predetermined second vessel speed threshold VP2 that is greater than the first vessel speed threshold VP1 after becoming equal to or lower than the first vessel speed threshold VP1 in example embodiments described above. Alternatively, in the present teaching, in the in-wave vessel speed control mode, the controller may change the parameter to be averaged to the first parameter value so as to increase a change in the vessel speed when the vessel speed becomes equal to or lower than the predetermined first vessel speed threshold, and change the parameter to be averaged to the second parameter value that is greater than the first parameter value when the vessel speed becomes higher than the first vessel speed threshold after becoming equal to or lower than the first vessel speed threshold. That is, in a control to change the parameter to be averaged, control hysteresis may not be set.

[0085] The controller 14 preferably decreases the parameter N to be averaged to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the vessel speed threshold VP in the in-wave vessel speed control mode in example embodiments described above. Alternatively, in the present teaching, the controller may not decrease the parameter to be averaged even when the vessel speed becomes equal to or lower than the vessel speed threshold in the in-wave vessel speed control mode.

[0086] In the in-wave vessel speed control mode, the controller 14 preferably changes the weighting coefficient K to the first weighting value K1 such that the weighting of the latest value Ian of the information Ia regarding upward-downward movement of the hull 10 is greater than the weighting of other than the latest value Ian of the information Ia regarding upward-downward movement of the hull 10, so as to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the predetermined first vessel speed threshold VP1, and changes the weighting coefficient K to the second weighting value K2 such that the weighting of the latest value Ian of the information Ia regarding upward-downward movement of the hull 10 is smaller as compared with a case in which the vessel speed V is equal to or lower than the first vessel speed threshold VP1 when the vessel speed V becomes equal to or higher than the predetermined second vessel speed threshold VP2 that is greater than the first vessel speed threshold VP1 after becoming equal to or lower than the first vessel speed threshold VP1 in example embodiments described above. Alternatively, in the present teaching, in the in-wave vessel speed control mode, the controller may change the weighting coefficient to the first weighting value such that the weighting of the latest value of the information regarding upward-downward movement of the hull is greater than the weighting of other than the latest value of the information regarding upward-downward movement of the hull, so as to increase a change in the vessel speed when the vessel speed becomes equal to or lower than the predetermined first vessel speed threshold, and change the weighting coefficient to the second weighting value such that the weighting of the latest value of the information regarding upward-downward movement of the hull is smaller as compared with a case in which the vessel speed is equal to or lower than the first vessel speed threshold when the vessel speed becomes higher than the first vessel speed threshold after becoming equal to or lower than the first vessel speed threshold. That is, in a control to change the weighting coefficient to adjust the weighting of the information regarding upward-downward movement of the hull, control hysteresis may not be set.

[0087] The controller 14 preferably changes the weighting coefficient K to adjust the weighting of the information Ia regarding upward-downward movement of the hull 10 such that the weighting of the latest value Ian of the information Ia regarding upward-downward movement of the hull 10 is greater than the weighting of other than the latest value Ian of the information Ia regarding upward-downward movement of the hull 10, so as to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the vessel speed threshold VP in the in-wave vessel speed control mode in example embodiments described above. Alternatively, in the present teaching, the controller may not change the weighting coefficient to adjust the weighting of the information regarding upward-downward movement of the hull even when the vessel speed becomes equal to or lower than the vessel speed threshold in the in-wave vessel speed control mode.

[0088] In the in-wave vessel speed control mode, the controller 14 preferably changes the predetermined period of time P during which the averaging is performed to the first period of time P1 so as to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the predetermined first vessel speed threshold VP1, and changes the predetermined period of time P during which the averaging is performed to the second period of time P2 that is longer than the first period of time P1 when the vessel speed V becomes equal to or higher than the predetermined second vessel speed threshold VP2 that is greater than the first vessel speed threshold VP1 after becoming equal to or lower than the first vessel speed threshold VP1 in example embodiments described above. Alternatively, in the present teaching, in the in-wave vessel speed control mode, the controller may change the predetermined period of time during which the averaging is performed to the first period of time so as to increase a change in the vessel speed when the vessel speed becomes equal to or lower than the predetermined first vessel speed threshold, and change the predetermined period of time during which the averaging is performed to the second period of time that is longer than the first period of time P1 when the vessel speed becomes higher than the first vessel speed threshold after becoming equal to or lower than the first vessel speed threshold. That is, in a control to change the predetermined period of time during which the controller performs the averaging, control hysteresis may not be set.

[0089] The controller 14 preferably reduces the predetermined period of time P during which the averaging is performed to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the vessel speed threshold VP in the in-wave vessel speed control mode in example embodiments described above. Alternatively, in the present teaching, the controller may not reduce the predetermined period of time during which the averaging is performed even when the vessel speed becomes equal to or lower than the vessel speed threshold in the in-wave vessel speed control mode.

[0090] The controller 14 preferably performs the in-wave vessel speed control to increase a change in the vessel speed V when the vessel speed V becomes equal to or lower than the predetermined vessel speed threshold VP that is greater than the minimum vessel speed V0 by the predetermined amount in the in-wave vessel speed control mode in example embodiments described above. Alternatively, in the present teaching, the controller may not perform the in-wave vessel speed control to increase a change in the vessel speed even when the vessel speed becomes equal to or lower than the predetermined vessel speed threshold that is greater than the minimum vessel speed by the predetermined amount in the in-wave vessel speed control mode.

[0091] The controller 14 preferably performs the notification control to notify the vessel user that the vessel speed V has become the minimum vessel speed V0 when the vessel speed V has become the minimum vessel speed V0 in the in-wave vessel speed control mode in example embodiments described above. Alternatively, in the present teaching, the controller may not perform the notification control to notify the vessel user that the vessel speed has become the minimum vessel speed even when the vessel speed has become the minimum vessel speed in the in-wave vessel speed control mode.

[0092] The controller 14 preferably performs the in-wave vessel speed control such that the vessel speed V becomes equal to or higher than the minimum vessel speed V0 that is set to be equal to or higher than the minimum speed at which the hull 10 is able to plane in the in-wave vessel speed control mode in example embodiments described above. Alternatively, in the present teaching, the controller may perform the in-wave vessel speed control such that the vessel speed becomes equal to or higher than a minimum vessel speed that is set to be lower than the minimum speed at which the hull is able to plane in the in-wave vessel speed control mode.

[0093] The operator 13 preferably includes a remote control and a steering wheel in example embodiments described above. Alternatively, in the present teaching, the operator may include a joystick. In such a case, the operator may include a joystick without including a remote control and a steering wheel, or may include a joystick in addition to a remote control and a steering wheel.

[0094] Only one propulsion device 20 is preferably attached to the stern 11 of the hull 10 in example embodiments described above. Alternatively, in the present teaching, more than one propulsion device may be attached to the stern of the hull.

[0095] The propulsion device 20 preferably includes an outboard motor attached to the stern 11 of the hull 10 in example embodiments described above. Alternatively, in the present teaching, the propulsion device may include an inboard motor inside the hull or an inboard-outboard motor attached to the hull such that a portion of the inboard-outboard motor is inside the hull.

Claims

1. A marine propulsion system (100) for a marine vessel (110) having a hull (10), the system comprising:

a propulsion device (20) configured to be provided on or in the hull (10); and

a controller (14) configured or programmed to control driving of the propulsion device (20) to adjust a vessel speed (V) of the marine vessel (110), and to perform an in-wave vessel speed control to adjust the vessel speed (V) based on information (Ia) regarding upward-downward movement of the hull (10); wherein

the controller (14) is configured or programmed to perform the in-wave vessel speed control such that the vessel speed (V) becomes equal to or higher than a predetermined minimum vessel speed (V0) in an in-wave vessel speed control mode in which the in-wave vessel speed control is performed.

2. The marine propulsion system (100) according to claim 1, further comprising an inertial measurement unit (16) configured to detect information (Ia) regarding upward-downward movement of the hull (10).

3. The marine propulsion system (100) according to claim 1 or 2, wherein the controller (14) is configured or programmed to perform the in-wave vessel speed control based on a moving average value obtained by averaging the information (Ia) regarding upward-downward movement of the hull (10) over a predetermined period of time (P).

4. The marine propulsion system (100) according to at least one of the claims 1 to 3, wherein the controller (14) is configured or programmed to perform the in-wave vessel speed control such that the vessel speed (V) becomes equal to or higher than the predetermined minimum vessel speed (V0) that is set to be equal to or higher than a minimum speed at which the hull (10) is able to plane in the in-wave vessel speed control mode.

5. The marine propulsion system (100) according to at least one of the claims 1 to 4, wherein the controller (14) is configured or programmed to perform a notification control to notify a user of the marine vessel (110) that the vessel speed (V) has become the predetermined minimum vessel speed (V0) when the vessel speed (V) has become the predetermined minimum vessel speed (V0) in the in-wave vessel speed control mode.

6. The marine propulsion system (100) according to claim 5, further comprising:

an operator (13) configured to receive an operation from the user of the marine vessel (110); wherein

the controller (14) is configured or programmed to, in the in-wave vessel speed control mode, perform the notification control when the vessel speed (V) has become the predetermined minimum vessel speed (V0), and change the predetermined minimum vessel speed (V0) when the user of the marine vessel (110) operates the operator (13) to change the predetermined minimum vessel speed (V0).

7. The marine propulsion system (100) according to claim 6, wherein the controller (14) is configured or programmed to, in the in-wave vessel speed control mode, perform the notification control when the vessel speed (V) has become the predetermined minimum vessel speed (V0), and increase the predetermined minimum vessel speed (V0) when the user of the marine vessel (110) operates the operator (13) to increase the predetermined minimum vessel speed (V0).

8. The marine propulsion system (100) according to at least one of the claims 5 to 7, further comprising a notification means (15) configured to notify the user of the marine vessel (110) that the vessel speed (V) has become the predetermined minimum vessel speed (V0) when the vessel speed (V) has become the predetermined minimum vessel speed (V0) in the in-wave vessel speed control mode.

9. The marine propulsion system (100) according to at least one of the claims 1 to 8, wherein the controller (14) is configured or programmed to perform the in-wave vessel speed control to control the propulsion device (20) to increase a change in the vessel speed (V) when the vessel speed (V) becomes equal to or lower than a predetermined vessel speed threshold (VP) that is greater than the predetermined minimum vessel speed (V0) by a predetermined amount in the in-wave vessel speed control mode.

10. The marine propulsion system (100) according to claim 9, wherein the controller (14) is configured or programmed to:
perform the in-wave vessel speed control based on a value obtained by averaging the information (Ia) regarding upward-downward movement of the hull (10) over a predetermined period of time (P).

11. The marine propulsion system (100) according to claim 10, wherein the controller (14) is configured or programmed to reduce the predetermined period of time (P) during which the averaging is performed to increase the change in the vessel speed (V) when the vessel speed (V) becomes equal to or lower than the predetermined vessel speed threshold (VP) in the in-wave vessel speed control mode.

12. The marine propulsion system (100) according to claim 11, wherein the controller (14) is configured or programmed to, in the in-wave vessel speed control mode, change the predetermined period of time (P) during which the averaging is performed to a first period of time (P1) so as to increase the change in the vessel speed (V) when the vessel speed (V) becomes equal to or lower than a predetermined first vessel speed threshold (VP1), and change the predetermined period of time (P) during which the averaging is performed to a second period of time (P2) that is longer than the first period of time (P1) when the vessel speed (V) becomes equal to or higher than a predetermined second vessel speed threshold (VP2) that is greater than the predetermined first vessel speed threshold (VP1) after becoming equal to or lower than the predetermined first vessel speed threshold (VP1).

13. The marine propulsion system (100) according to claim 10, wherein the controller (14) is configured or programmed to change a weighting coefficient (K) to adjust a weighting of the information (Ia) regarding upward-downward movement of the hull (10) such that a weighting of a latest value (Ian) of the information (Ia) regarding upward-downward movement of the hull (10) is greater than a weighting of other than the latest value (Ian) of the information (Ia) regarding upward-downward movement of the hull (10), so as to increase the change in the vessel speed (V) when the vessel speed (V) becomes equal to or lower than the predetermined vessel speed threshold (VP) in the in-wave vessel speed control mode.

14. The marine propulsion system (100) according to claim 13, wherein the controller (14) is configured or programmed to, in the in-wave vessel speed control mode, change the weighting coefficient (K) to a first weighting value (K1) such that the weighting of the latest value (Ian) of the information (Ia) regarding upward-downward movement of the hull (10) is greater than the weighting of other than the latest value (Ian) of the information (Ia) regarding upward-downward movement of the hull (10), so as to increase the change in the vessel speed (V) when the vessel speed (V) becomes equal to or lower than a predetermined first vessel speed threshold (VP1), and change the weighting coefficient (K) to a second weighting value (K2) such that the weighting of the latest value (Ian) of the information (Ia) regarding upward-downward movement of the hull (10) is smaller as compared with a case in which the vessel speed (V) is equal to or lower than the predetermined first vessel speed threshold (VP1) when the vessel speed (V) becomes equal to or higher than a predetermined second vessel speed threshold (VP2) that is greater than the predetermined first vessel speed threshold (VP1) after becoming equal to or lower than the predetermined first vessel speed threshold (VP1).

15. The marine propulsion system (100) according to claim 10, wherein the controller (14) is configured or programmed to decrease a parameter (N) to be averaged to increase the change in the vessel speed (V) when the vessel speed (V) becomes equal to or lower than the predetermined vessel speed threshold (VP) in the in-wave vessel speed control mode.

16. The marine propulsion system (100) according to claim 15, wherein the controller (14) is configured or programmed to, in the in-wave vessel speed control mode, change the parameter (N) to be averaged to a first parameter value (N1) so as to increase the change in the vessel speed (V) when the vessel speed (V) becomes equal to or lower than a predetermined first vessel speed threshold (VP1), and change the parameter (N) to be averaged to a second parameter value (N2) that is greater than the first parameter value (N1) when the vessel speed (V) becomes equal to or higher than a predetermined second vessel speed threshold (VP2) that is greater than the predetermined first vessel speed threshold (VP1) after becoming equal to or lower than the predetermined first vessel speed threshold (VP1).

17. The marine propulsion system (100) according to claim 9, wherein the controller (14) is configured or programmed to increase a maximum value (MM) of a rate of change of the vessel speed (V) so as to increase the change in the vessel speed (V) when the vessel speed (V) becomes equal to or lower than the predetermined vessel speed threshold (VP) in the in-wave vessel speed control mode.

18. The marine propulsion system (100) according to claim 17, wherein the controller (14) is configured or programmed to, in the in-wave vessel speed control mode, change the maximum value (MM) of the rate of change of the vessel speed (V) to a first maximum value (MM1) of the rate of change so as to increase the change in the vessel speed (V) when the vessel speed (V) becomes equal to or lower than a predetermined first vessel speed threshold (VP1), and change the maximum value (MM) of the rate of change of the vessel speed (V) to a second maximum value (MM2) of the rate of change that is smaller than the first maximum value (MM1) of the rate of change when the vessel speed (V) becomes equal to or higher than a predetermined second vessel speed threshold (VP2) that is greater than the predetermined first vessel speed threshold (VP1) after becoming equal to or lower than the predetermined first vessel speed threshold (VP1).

19. A method for controlling a marine vessel (110) having a hull (10) and a marine propulsion system (100) comprising a propulsion device (20) provided on or in the hull (10); and a controller (14) configured or programmed to control driving of the propulsion device (20) to adjust a vessel speed (V) of the marine vessel (110), the method comprising:

performing an in-wave vessel speed control to adjust the vessel speed (V) based on information (Ia) regarding upward-downward movement of the hull (10); wherein

the in-wave vessel speed control is performed such that the vessel speed (V) becomes equal to or higher than a predetermined minimum vessel speed (V0) in an in-wave vessel speed control mode in which the in-wave vessel speed control is performed.

Drawing