CONTROL SYSTEM FOR WATERCRAFT AND METHOD FOR CONTROLLING WATERCRAFT

Abstract

A control system for a watercraft includes a marine propulsion device, a load sensor, and a computer. The load sensor is operable detect load data regarding a drive source of the marine propulsion device. The computer is configured or programmed to store a decision logic to determine whether or not a malfunction or trouble of the watercraft has occurred, obtain the load data, and determine whether or not the malfunction or trouble of the watercraft has occurred based on the load data with reference to the decision logic. The load logic includes at least one of a foreign object attachment decision logic, a propeller matching decision logic, a damper slippage decision logic, or a water landing decision logic.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese Patent Application No. 2023-050543 filed on Mar. 27, 2023. The entire contents of this application are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to control systems for watercraft and methods for controlling watercraft.

2. Description of the Related Art

There has been known a system that a controller installed in a watercraft detects status data from a variety of devices in the watercraft, and then, based on the status data indicating statuses of the devices, determines whether or not a malfunction or trouble of the watercraft has occurred. For example, Japan Laid-open Patent Application Publication No. 2011-113538 describes that a watercraft information collecting device is installed in a watercraft. The watercraft information collecting device obtains watercraft information of a variety of devices and determines whether or not a malfunction or trouble has occurred based on values of the watercraft information. The watercraft information collecting device is communicable with an onshore server and transmits the watercraft information to the onshore server when determining that the malfunction or trouble has occurred.

In the system described above, the controller has stored a decision logic to determine whether or not the malfunction or trouble has occurred. With reference to the decision logic, the controller determines whether or not the malfunction or trouble has occurred based on the status data. For example, the watercraft information collecting device obtains a value detected by a vibrometer and determines that the malfunction or trouble has occurred when the detected value is greater than a threshold.

However, a variety of malfunctions or troubles occur in the watercraft. For example, when foreign objects such as barnacles are attached to the watercraft, this increases water resistance acting on the watercraft such that the watercraft has degraded fuel economy. However, the attachment of the barnacles to the watercraft gradually advances. Thus, it is difficult for a user of the watercraft to notice the attachment of the barnacles at an early stage.

On the other hand, a propeller is attached to a marine propulsion device. When the propeller attached to the marine propulsion device is not matched with either the watercraft or the marine propulsion device, the marine propulsion device cannot perform to the maximum extent. However, it is difficult for the user of the watercraft to notice that the propeller is not matched with the watercraft or the marine propulsion device.

Additionally, the propeller is attached to a propeller shaft through a propeller damper in the marine propulsion device. The propeller damper is made of an elastic material such as rubber. Thus, the propeller damper deteriorates with usage or an elapse of time. When the propeller damper deteriorates, slippage may occur between the propeller and the propeller shaft. In this case, a vessel speed does not appropriately increase with an increase in the engine rotational speed. However, it is difficult for the user of the watercraft to notice an occurrence of slippage attributed to the propeller damper.

Additionally, the watercraft may temporarily separate from the water surface when planning in a relatively high wave environment. In such a case, the watercraft is subject to impacts when landing on the water. When the watercraft is frequently operated under such an environment, a malfunction or trouble may occur in the watercraft. However, it is difficult for a dealer in charge of repairing or maintenance of the watercraft to know the frequency of impacts subjected to the watercraft due to landing on the water. Because of this, it is not easy for the dealer to know the cause of the malfunction or trouble.

SUMMARY OF THE INVENTION

Example embodiments of the present invention determine a malfunction or trouble of a watercraft at an early stage based on a load acting on a drive source.

A control system for a watercraft according to an example embodiment of the present invention includes a marine propulsion device, a load sensor, and a computer. The marine propulsion device includes a drive source. The load sensor is operable to detect load data indicating a load acting on the drive source. The computer is configured or programmed to store a decision logic to determine whether or not a malfunction or trouble of the watercraft has occurred, obtain the load data, and determine whether or not the malfunction or trouble of the watercraft has occurred based on the load data with reference to the decision logic. The decision logic includes at least one of a foreign object attachment decision logic, a propeller matching decision logic, a damper slippage decision logic, or a water landing decision logic. The foreign object attachment decision logic determines whether or not attachment of a foreign object to the watercraft has occurred. The propeller matching decision logic determines whether or not a propeller appropriately matches the marine propulsion device. The damper slippage decision logic determines whether or not slippage of a propeller damper has occurred in the marine propulsion device. The water landing decision logic determines whether or not a water landing of the watercraft has occurred.

A method according to another example embodiment of the present invention relates to a method of controlling a watercraft. The watercraft includes a marine propulsion device including a drive source. The method includes obtaining load data indicating a load acting on the drive source and determining whether or not a malfunction or trouble of the watercraft has occurred based on the load data with reference to a decision logic to determine whether or not the malfunction or trouble of the watercraft has occurred. The decision logic includes at least one of a foreign object attachment decision logic, a propeller matching decision logic, a damper slippage decision logic, or a water landing decision logic. The foreign object attachment decision logic determines whether or not attachment of a foreign object to the watercraft has occurred. The propeller matching decision logic determines whether or not a propeller appropriately matches the marine propulsion device. The damper slippage decision logic determines whether or not slippage of a propeller damper has occurred in the marine propulsion device. The water landing decision logic determines whether or not a water landing of the watercraft has occurred.

The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the example embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a watercraft according to an example embodiment of the present invention.

FIG. 2 is a side view of a marine propulsion device.

FIG. 3 is a schematic cross-sectional view of a drive source.

FIG. 4A is an enlarged view of a shift mechanism.

FIG. 4B is an enlarged view of the shift mechanism.

FIG. 5A is a diagram showing a tilt motion of the marine propulsion device.

FIG. 5B is a diagram showing the tilt motion of the marine propulsion device.

FIG. 6 is a block diagram showing a control system for the marine propulsion device.

FIG. 7 is a diagram showing a phase detecting method executed by each of a crank sensor and a cam sensor.

FIG. 8 is a block diagram showing a configuration of a control system for the watercraft according to an example embodiment of the present invention.

FIG. 9 is a block diagram showing a configuration of a watercraft computer.

FIG. 10 is a chart exemplifying a normal load region and a present load region in a foreign object attachment decision logic.

FIG. 11 is a chart exemplifying cargo data in the foreign object attachment decision logic.

FIG. 12 is a chart exemplifying a normal load region and a present load region in a propeller matching decision logic.

FIG. 13 is a chart exemplifying a normal load region and a present load region in a damper slippage decision logic.

FIG. 14 is a chart exemplifying a normal load region and present load data in a water landing decision logic.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

Example embodiments of the present invention will be hereinafter explained with reference to drawings. FIG. 1 is a perspective view of a watercraft 100 according to an example embodiment of the present invention. A marine propulsion device 1 is attached to the stern of the watercraft 100. The marine propulsion device 1 generates a thrust to propel the watercraft 100. In the present example embodiment, the marine propulsion device 1 is an outboard motor. The marine propulsion device 1 is attached to the watercraft 100 through a bracket 2.

FIG. 2 is a side view of the marine propulsion device 1. As shown in FIG. 2, the marine propulsion device 1 includes a drive source 10, a drive shaft 11, a propeller shaft 12, and a shift mechanism 13. The drive source 10 generates the thrust to propel the watercraft 100 as a drive source. The drive source 10 is an engine. The drive source 10 includes a crankshaft 14. The crankshaft 14 extends in a vertical direction. A flywheel 15 is connected to the crankshaft 14. The drive source 10 includes a starter motor 16. The starter motor 16 is connected to the crankshaft 14 so as to start the drive source 10.

FIG. 3 is a schematic cross-sectional view of the drive source 10. As shown in FIG. 3, the drive source 10 includes a piston 17 and a connecting rod 18. The piston 17 is connected to the crankshaft 14 through the connecting rod 18. The drive source 10 includes a combustion chamber 21, an intake port 22, and an exhaust port 23. The intake port 22 and the exhaust port 23 are in communication with the combustion chamber 21. The drive source 10 includes an intake pipe 24, an exhaust pipe 25, an intake valve 26, and an exhaust valve 27.

The intake pipe 24 is connected to the intake port 22. The intake valve 26 opens and closes the intake port 22. The exhaust pipe 25 is connected to the exhaust port 23. The exhaust valve 27 opens and closes the exhaust port 23. The drive source 10 includes an exhaust camshaft 28 and an intake camshaft 29. The exhaust camshaft 28 and the intake camshaft 29 are connected to the crankshaft 14 through a timing belt 30 shown in FIG. 2. The intake valve 26 is driven by the intake camshaft 29. The exhaust valve 27 is driven by the exhaust camshaft 28.

The drive source 10 includes a throttle valve 31, a fuel injection device 32, and an ignition device 33. The throttle valve 31 is attached to the intake pipe 24. The amount of mixture gas to be fed to the combustion chamber 21 is regulated by changing the opening degree of the throttle valve 31. The fuel injection device 32 is attached to the intake pipe 24. A delivery pipe 34 is connected to the fuel injection device 32. The delivery pipe 34 is kept at a predetermined pressure in the interior thereof and supplies fuel therethrough to the fuel injection device 32. The fuel injection device 32 injects the fuel into the intake pipe 24. The ignition device 33 is inserted into the combustion chamber 21 and ignites the fuel.

As shown in FIG. 2, the drive shaft 11 is connected to the crankshaft 14. The drive shaft 11 extends in the vertical direction. The drive shaft 11 extends downward from the drive source 10. The propeller shaft 12 extends in a back-and-forth direction of the marine propulsion device 1. The propeller shaft 12 is connected to the drive shaft 11 through the shift mechanism 13. A propeller 19 is connected to the propeller shaft 12 through a propeller damper 20. The propeller damper 20 is made of an elastic material such as rubber. The shift mechanism 13 switches the rotational direction of mechanical power to be transmitted from the drive shaft 11 to the propeller shaft 12.

FIGS. 4A and 4B are enlarged views of the shift mechanism 13. As shown in FIGS. 4A and 4B, the shift mechanism 13 includes a drive gear 35, a forward moving gear 36, a rearward moving gear 37, a dog clutch 38, and a shift actuator 39. The drive gear 35 is connected to the drive shaft 11. The drive gear 35, the forward moving gear 36, and the rearward moving gear 37, each of which is a bevel gear, are meshed with each other. The forward moving gear 36 and the rearward moving gear 37 are coaxial to the propeller shaft 12 so as to be freely rotatable with respect thereto. The dog clutch 38 is movable to a forward moving position, a rearward moving position, and a neutral position.

FIG. 4A shows the dog clutch 38 located in the forward moving position. When located in the forward moving position, the dog clutch 38 causes the forward moving gear 36 to be engaged with the propeller shaft 12, while causing the rearward moving gear 37 to be disengaged from the propeller shaft 12. Accordingly, the shift mechanism 13 transmits the rotation of the drive shaft 11 to the propeller shaft 12 such that the propeller shaft 12 is rotated in a forward moving direction. FIG. 4B shows the dog clutch 38 located in the rearward moving position. When located in the rearward moving position, the dog clutch 38 causes the rearward moving gear 37 to be engaged with the propeller shaft 12, while causing the forward moving gear 36 to be disengaged from the propeller shaft 12. Accordingly, the shift mechanism 13 transmits the rotation of the drive shaft 11 to the propeller shaft 12 such that the propeller shaft 12 is rotated in a rearward moving direction.

The neutral position is located between the forward moving position and the rearward moving position. When located in the neutral position, the dog clutch 38 causes both the forward moving gear 36 and the rearward moving gear 37 to be disengaged from the propeller shaft 12. Accordingly, the rotation of the drive shaft 11 is not transmitted to the propeller shaft 12. The shift actuator 39 causes the dog clutch 38 to be moved among the forward moving position, the neutral position, and the rearward moving position. Accordingly, engagement between the dog clutch 38 and the gears 35 to 37 and disengagement therebetween are switched. The shift actuator 39 includes, for instance, an electric motor. The shift actuator 39 is connected to the dog clutch 38 through a shift member 40.

As shown in FIG. 2, the marine propulsion device 1 includes a tilt mechanism 41. The tilt mechanism 41 is attached to the watercraft 100. The tilt mechanism 41 includes a tilt shaft 42 and a tilt actuator 43. The tilt mechanism 41 supports the marine propulsion device 1 such that the marine propulsion device 1 is pivotable about the tilt shaft 42. The tilt actuator 43 includes, for instance, a hydraulic cylinder. The tilt actuator 43 may be another type of actuator such as an electric cylinder. As shown in FIGS. 5A and 5B, the tilt actuator 43 causes the marine propulsion device 1 to pivot about the tilt shaft 42.

FIG. 6 is a block diagram showing a control system for the marine propulsion device 1. As shown in FIG. 6, the marine propulsion device 1 includes an ECU (Engine Control Unit) 50. The ECU 50 is an electronic control device to control the drive source 10. The ECU 50 includes a processor 51 such as a CPU (Central Processing Unit) and a storage device 52. The storage device 52 includes memories such as a RAM (Random Access Memory) and a ROM (Read Only Memory). The storage device 52 may include a storage such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive). The storage device 52 stores programs and data to control the marine propulsion device 1. The processor 51 controls the marine propulsion device 1 based on the programs and data.

The marine propulsion device 1 includes a load sensor 49. The load sensor 49 detects load data indicating a load acting on the drive source 10. The load sensor 49 includes an engine speed sensor 53, a vessel speed sensor 54, a throttle opening degree sensor 55, and an intake pressure sensor 59. The engine speed sensor 53 detects an engine rotational speed. The engine speed sensor 53 outputs a signal, indicating the engine rotational speed, to the ECU 50. The vessel speed sensor 54 detects a vessel speed. The vessel speed sensor 54 outputs a signal, indicating the vessel speed, to the ECU 50. The throttle opening degree sensor 55 detects a throttle opening degree. The throttle opening degree sensor 55 outputs a signal, indicating the throttle opening degree, to the ECU 50. The intake pressure sensor 59 detects an intake pressure inside the intake pipe 24. The intake pressure sensor 59 outputs a signal, indicating the intake pressure inside the intake pipe 24, to the ECU 50. The marine propulsion device 1 includes an exhaust pressure sensor 60. The exhaust pressure sensor 60 detects an exhaust pressure inside the exhaust pipe 25. The exhaust pressure sensor 60 outputs a signal, indicating the exhaust pressure inside the exhaust pipe 25, to the ECU 50.

The marine propulsion device 1 includes a crank sensor 56 and a cam sensor 57. The crank sensor 56 detects the phase of the crankshaft 14. As shown in FIG. 7, the flywheel 15 connected to the crankshaft 14 is provided with a plurality of protrusions 141 regularly aligned on the surface thereof. The flywheel 15 is provided with a missing region 142 on the surface thereof. The protrusions 141 are not provided in the missing region 142 and the interval between a pair of adjacent protrusions 141 defining the missing region 142 is different from that between each other pair of adjacent protrusions 141. The crank sensor 56 is a magnetic sensor and detects passage of the plurality of protrusions 141. It should be noted that in FIG. 7, reference sign 141 is assigned to only a portion of the plurality of protrusions 141. The crank sensor 56 detects the phase of the crankshaft 14 by detecting the missing region 142. The crank sensor 56 outputs a signal, indicating the phase of the crankshaft 14, to the ECU 50.

The cam sensor 57 detects the phase of the exhaust camshaft 28. The exhaust camshaft 28 is provided with a plurality of protrusions 281 regularly aligned on the surface thereof. It should be noted that the exhaust camshaft 28 is provided with a missing region 282 on the surface thereof. The protrusions 281 are not provided in the missing region 282 and the interval between a pair of adjacent protrusions 281 defining the missing region 282 is different from that between each other pair of adjacent protrusions 281. The cam sensor 57 is a magnetic sensor and detects passage of the plurality of protrusions 281 provided on the exhaust camshaft 28. It should be noted that in FIG. 7, reference sign 281 is assigned to only a portion of the plurality of protrusions 281. The cam sensor 57 detects the phase of the exhaust camshaft 28 by detecting the missing region 282. The cam sensor 57 outputs a signal, indicating the phase of the exhaust camshaft 28, to the ECU 50.

The marine propulsion device 1 includes a fuel pressure sensor 58. The fuel pressure sensor 58 detects the pressure of the fuel inside the delivery pipe 34. The fuel pressure sensor 58 outputs a signal, indicating the pressure of the fuel inside the delivery pipe 34, to the ECU 50.

The marine propulsion device 1 includes a shift position sensor 61. The shift position sensor 61 detects the position of the dog clutch 38 (hereinafter referred to as “shift position”). The shift position sensor 61 detects, as the shift position, in which of the forward moving position, the neutral position, and the rearward moving position the dog clutch 38 is located. The shift position sensor 61 outputs a signal, indicating the shift position, to the ECU 50.

The marine propulsion device 1 includes a tilt switch 62 and a tilt position sensor 63. The tilt switch 62 is operable by an operator. The tilt actuator 43 is driven in response to the operation of the tilt switch 62 such that the marine propulsion device 1 pivots about the tilt shaft 42. The tilt position sensor 63 detects the position of the marine propulsion device 1 tilting about the tilt shaft 42. The tilt position sensor 63 outputs a signal, indicating the tilt position of the marine propulsion device 1 about the tilt shaft 42, to the ECU 50. It should be noted that a pivot speed of the marine propulsion device 1 about the tilt shaft 42 is calculated based on the tilt position of the marine propulsion device 1 about the tilt shaft 42.

FIG. 8 is a schematic diagram showing a configuration of a control system 200 for the watercraft 100 according to an example embodiment. As shown in FIG. 8, the control system 200 includes a communication device 3, a device system 4, and a watercraft computer 5. The communication device 3, the device system 4, and the watercraft computer 5 are installed in the watercraft 100. The communication device 3 performs wireless communication with a server 6 remote from the watercraft 100. For example, the communication device 3 is able to perform data communication with external entities, i.e., the server 6 and a user terminal 7, through a mobile communication network 300. The user terminal 7 includes, for instance, a personal computer. The user terminal 7 may be a mobile computer such as a smartphone or a tablet. The mobile communication network 300 is, for instance, a network of a 3G, 4G, or 5G mobile communication system.

The device system 4 includes electric devices installed in the watercraft 100. For example, the device system 4 includes the ECU 50 described above. The device system 4 includes a throttle-shift operating device 64. The throttle-shift operating device 64 is operable by the operator to regulate the engine rotational speed of the marine propulsion device 1. Additionally, the throttle-shift operating device 64 is operable by the operator to switch the action of the marine propulsion device 1 between a forward moving action and a rearward moving action.

The throttle-shift operating device 64 includes a throttle operator 65. The throttle operator 65 is operable from a neutral position to a forward moving position and a rearward moving position. The throttle operator 65 is operated to control an output of the drive source 10. The throttle operator 65 includes, for instance, a lever. The throttle operator 65 may be another type of member such as a switch or a joystick. The throttle-shift operating device 64 outputs a throttle signal indicating the operating position of the throttle operator 65. The ECU 50 receives the throttle signal outputted from the throttle-shift operating device 64. The ECU 50 controls the shift mechanism 13 in accordance with the operating position of the throttle operator 65. Accordingly, the rotational direction of the propeller shaft 12 is switched between the forward moving direction and the rearward moving direction. Additionally, the ECU 50 controls the engine rotational speed by controlling the throttle opening degree and the amount of fuel injection in accordance with the operating position of the throttle operator 65.

The device system 4 includes a steering actuator 66 and a steering operating device 67. The steering actuator 66 turns the marine propulsion device 1 right and left so as to change a rudder angle of the marine propulsion device 1. The steering actuator 66 includes, for instance, an electric motor. Alternatively, the steering actuator 66 may include an electric pump and a hydraulic cylinder.

The steering operating device 67 is operable by the operator to adjust the rudder angle of the marine propulsion device 1. The steering operating device 67 includes, for instance, a steering wheel. Alternatively, the steering operating device 67 may be another type of operating device such as a joystick. The steering operating device 67 is operable right and left from a neutral position. The steering operating device 67 outputs a steering signal indicating the operating position thereof. The steering actuator 66 is controlled in accordance with the operating position of the steering operating device 67 such that the rudder angle of the marine propulsion device 1 is controlled.

The device system 4 includes a battery 68 and a battery sensor 69. The battery 68 supplies electric power to the device system 4. The battery sensor 69 includes a voltmeter and an ammeter. The battery sensor 69 detects a voltage and current of the battery 68. The battery sensor 69 outputs a signal, indicating the voltage and current of the battery 68, to the watercraft computer 5.

The device system 4 includes a start switch 71 and a kill switch 72. The start switch 71 and the kill switch 72 are operable by the operator. The start switch 71 starts the drive source 10 by driving the starter motor 16. The starter motor 16 is driven by electric power supplied thereto from the battery 68. The kill switch 72 is normally kept turned off. In the off state of the kill switch 72, driving of the drive source 10 is enabled. When the kill switch 72 is turned on, driving of the drive source 10 is stopped. For example, in the on state of the kill switch 72, the supply of electric power to the ignition device 33 is stopped.

The device system 4 includes a display 73 and an input device 74. The display 73 displays information regarding the marine propulsion device 1. The display 73 displays an image in accordance with an image signal inputted thereto. The input device 74 receives an operational input by a user. The input device 74 outputs an input signal indicating the operational input by the user. The input device 74 includes, for instance, a touchscreen. However, the input device 74 may include at least one hardware key.

The device system 4 includes a CAN (Controller Area Network) 75. The electric devices, included in the device system 4, are connected to each other through the CAN 75 in a communicable manner.

The watercraft computer 5 includes a processor 76 such as a CPU and a storage device 77. The storage device 77 includes memories such as a RAM and a ROM. The storage device 77 may include a storage such as an HDD or an SSD. The storage device 77 stores programs and data to control the device system 4. The processor 76 controls the device system 4 based on the programs and data. For example, the watercraft computer 5 controls the device system 4 in accordance with the input signal transmitted thereto from the input device 74. The watercraft computer 5 outputs the image signal to the display 73 such that the display 73 is caused to display a desired image.

The watercraft computer 5 is connected to the ECU 50 in a communicable manner. The watercraft computer 5 obtains status data, indicating statuses of the marine propulsion device 1, through the ECU 50. For example, the watercraft computer 5 obtains the engine rotational speed, the vessel speed, and the throttle opening degree as the status data. The watercraft computer 5 obtains the phase of the exhaust camshaft 28 and that of the crankshaft 14 as the status data. The watercraft computer 5 obtains the fuel pressure, the intake pressure, and the exhaust pressure as the status data. The watercraft computer 5 obtains the shift position and the tilt position as the status data.

Additionally, the watercraft computer 5 obtains the status data, indicating statuses of the other devices in the device system 4, through the CAN 75. For example, the watercraft computer 5 obtains the voltage and current of the battery 68 as the status data. The watercraft computer 5 obtains whether the kill switch 72 is kept turned on or off as the status data.

As shown in FIG. 9, the watercraft computer 5 stores a decision logic 80 to determine whether or not a malfunction or trouble of the watercraft 100 has occurred. The decision logic 80 includes algorithms associated with a variety of types of malfunctions or troubles on a one-to-one basis so as to determine whether or not a predetermined type of malfunction or trouble has occurred. With reference to the decision logic 80, the watercraft computer 5 determines whether or not the malfunction or trouble of the watercraft 100 has occurred based on the status data. A method for determining the malfunction or trouble of the watercraft 100 will be hereinafter explained.

With reference to the decision logic 80, the watercraft computer 5 determines whether or not the malfunction or trouble of the watercraft 100 has occurred based on the load data of the drive source 10. The load data of the drive source 10 include the engine rotational speed, the vessel speed, the operating amount of the throttle operator 65, and the intake pressure among the data items included in the status data described above. The decision logic 80 includes a foreign object attachment decision logic 81, a propeller matching decision logic 82, a damper slippage decision logic 83, and a water landing decision logic 84.

The foreign object attachment decision logic 81 determines whether or not attachment of a foreign object (e.g., barnacles) to the watercraft 100 has occurred based on the intake pressure and the engine rotational speed, both of which are indicated by present load data. More specifically, with reference to the foreign object attachment decision logic 81, the watercraft computer 5 determines whether or not the attachment of the foreign object has occurred by comparing the present load data and the initial load data. The initial load data indicate a relationship between the vessel speed and the load acting on the drive source 10 in an initial state of the watercraft 100.

FIG. 10 is a chart exemplifying a normal load region A1 indicated by the initial load data and a present load region B1 indicated by the present load data. The initial load data define a relationship between the engine rotational speed and the intake pressure in the initial state of the watercraft 100. The present load data define a relationship between the engine rotational speed and the intake pressure in the present state of the watercraft 100. It should be noted that in FIG. 10, “N1” is a value of the engine rotational speed when idling, whereas “P1” is a value of the intake pressure when idling. “N3” is a value of the engine rotational speed at a full throttle opening degree, whereas “P3” is a value of the intake pressure at a full throttle opening degree. “N2” is a value greater than N1 and less than N3, whereas “P2” is a value greater than P1 and less than P3.

The normal load region A1 indicates a steady region defined by the engine rotational speed and the intake pressure when the speed of the watercraft 100 is increased slowly enough in the initial state of the watercraft 100. The steady region varies among individual products of the watercraft 100. Thus, the watercraft computer 5 has preliminarily stored a steady region defined by the engine rotational speed and the intake pressure in a PDI (Pre-Delivery Inspection) as the initial load data.

The watercraft computer 5 obtains the present load data during steady navigation of the watercraft 100. The watercraft computer 5 determines that the attachment of the foreign object to the watercraft 100 has occurred when the load indicated by the present load data is higher than that indicated by the initial load data by a predetermined value or greater. For example, as shown in FIG. 10, the watercraft computer 5 calculates the present load region B1 from a plurality of sets of present load data. The watercraft computer 5 determines that the attachment of the foreign object to the watercraft 100 has occurred when the present load region B1 is higher than the normal load region A1 by a predetermined value or greater. In other words, the watercraft computer 5 determines that the attachment of the foreign object to the watercraft 100 has occurred when the load indicated by the present load data is steadily higher than that indicated by the initial load data by the predetermined value or greater.

Additionally, the watercraft computer 5 obtains cargo data indicating the weight of a cargo loaded on the watercraft 100. The watercraft computer 5 determines whether or not the attachment of the foreign object to the watercraft 100 has occurred in consideration of the cargo data. FIG. 11 is a chart exemplifying the cargo data. As shown in FIG. 11, the cargo data are indicated as a vessel speed curve C1 in acceleration of the watercraft 100. The watercraft computer 5 stores the vessel speed curve C1 in a normal state. The vessel speed curve C1 in the normal state corresponds to a vessel speed curve in the PDI.

As shown in FIG. 11, the watercraft computer 5 calculates a vessel speed curve C2 in the present state from the present vessel speed. The watercraft computer 5 determines that the watercraft 100 is in a heavily loaded state when an acceleration at a quite low speed indicated by the vessel speed curve C2 in the present state is lower than that indicated by the vessel speed curve C1 in the normal state by a predetermined value or greater. The watercraft computer 5 determines that the watercraft 100 is in a lightly loaded state when the acceleration at the quite low speed indicated by the vessel speed C2 in the present state is not lower than that indicated by the vessel speed curve C1 in the normal state by the predetermined value or greater. The watercraft computer 5 determines that the attachment of the foreign object to the watercraft 100 has occurred when the watercraft 100 is in the lightly loaded state, and simultaneously, the load indicated by the present load data is higher than that indicated by the initial load data by the predetermined value or greater. Accordingly, when the watercraft 100 has a reduced acceleration due to the cargo heavily loaded thereon, it is made possible to prevent an erroneous determination from being made regarding whether or not the attachment of the foreign object to the watercraft 100 has occurred.

The propeller matching decision logic 82 determines whether or not the propeller 19 appropriately matches the marine propulsion device 1. With reference to the propeller matching decision logic 82, the watercraft computer 5 determines that the propeller 19 does not appropriately match the marine propulsion device 1 when the present load data are plotted outside of a normal load region during the steady navigation of the watercraft 100.

The normal load region in the propeller matching indicates a steady region defined by the engine rotational speed and the intake pressure when the propeller 19 appropriately matches the marine propulsion device 1. The normal load region in the propeller matching also indicates a steady region defined by the engine rotational speed and the intake pressure at the full throttle opening degree. With reference to the propeller matching decision logic 82, it is determined whether or not the propeller 19 appropriately matches based on the present load region at the full throttle opening degree.

FIG. 12 is a chart exemplifying a normal load region A2 in the propeller matching logic. As shown in FIG. 12, the watercraft computer 5 determines that the propeller 19 does not appropriately match when a present load region B2a is plotted outside of the normal load region A2. The engine rotational speed at the full throttle opening degree is lower in the present load region B2a than in the normal load region A2. Because of this, the watercraft computer 5 determines that the propeller 19 is too large in pitch or diameter.

Additionally, as shown in FIG. 12, when a present load region B2b is plotted outside of the normal load region A2, the watercraft computer 5 determines that the propeller 19 does not appropriately match. The engine rotational speed in the present load region B2b reaches that in the normal load region A2 before the throttle opening degree reaches the full throttle opening degree. Because of this, the watercraft computer 5 determines that the propeller 19 is too small in pitch or diameter.

The damper slippage decision logic 83 determines whether or not slippage of the propeller damper 20 has occurred in the marine propulsion device 1. With reference to the damper slippage decision logic 83, the watercraft computer 5 determines that the slippage of the propeller damper 20 has occurred in the marine propulsion device 1 when the load acting on the drive source 10, indicated by the present load data, has been reduced from the initial load data by a predetermined value or greater.

For example, as shown in FIG. 13, the watercraft computer 5 determines that the slippage of the propeller damper 20 has occurred when a present load region B3 is lower than a normal load region A3 by a predetermined value or greater. In other words, the watercraft computer 5 determines that the slippage of the propeller damper 20 has occurred when the load indicated by the present load data is steadily lower than that indicated by the initial load data by a predetermined value or greater. It should be noted that the normal load region A3 may be identical to the normal load region A1 described above.

The water landing decision logic 84 determines whether or not a water landing of the watercraft 100 has occurred. With reference to the water landing decision logic 84, the watercraft computer 5 determines that the watercraft 100 has separated from the water surface and has then landed on the water when the engine rotational speed has increased by a predetermined value or greater even though the operating amount of the throttle operator 65 has been kept constant. For example, as shown in FIG. 14, it has been determined that a water landing of the watercraft 100 has occurred when the present load data have changed from a first load L1 plotted within a normal load region A4 into a second load L2 plotted outside of the normal load region A4, and subsequently, changed to a load plotted within the normal load region A4. The second load L2 is higher in engine rotational speed than the first load L1 by a predetermined value or greater.

It should be noted that the normal load region A4 may be identical to the normal load region A1 described above. Alternatively, when predetermined operational conditions are satisfied, the watercraft computer 5 may determine that the water landing of the watercraft 100 has occurred as does with reference to the water landing decision logic 84 described above. The predetermined operational conditions include the conditions that the engine rotational speed is greater than or equal to a predetermined rotational speed threshold, that the shift position is set in the forward moving position, and that the vessel speed is greater than or equal to a predetermined speed threshold.

When it is determined that the malfunction or trouble has occurred, the watercraft computer 5 causes the display 73 to display a notification of the malfunction or trouble. When it is determined that the malfunction or trouble has occurred, the watercraft computer 5 transmits the notification of the malfunction or trouble to the server 6. Alternatively, when it is determined that the malfunction or trouble has occurred, the watercraft computer 5 transmits the notification of the malfunction or trouble to the user terminal 7.

In the control system 200 for the watercraft 100 according to an example embodiment explained above, it is determined whether or not the malfunction or trouble of the watercraft 100 has occurred based on the load data with reference to the decision logic 80. The decision logic 80 includes the foreign object attachment decision logic 81 to determine whether or not the attachment of the foreign object to the watercraft 100 has occurred, the propeller matching decision logic 82 to determine whether or not the propeller 19 appropriately matches the marine propulsion device 1, the damper slippage decision logic 83 to determine whether or not the slippage of the propeller damper 20 has occurred in the marine propulsion device 1, and the water landing decision logic 84 to determine whether or not the water landing of the watercraft 100 has occurred. Because of this, the user or dealer of the watercraft 100 is able to notice the malfunctions or troubles described above at an early stage.

It should be noted that the watercraft computer 5 obtains data to update the decision logic 80 from the server 6. The watercraft computer 5 updates the decision logic 80 based on the updated data. Then, with reference to the updated decision logic 80, the watercraft computer 5 determines whether or not the malfunction or trouble of the watercraft 100 has occurred based on the status data. Accordingly, the watercraft computer 5 is able to determine whether or not the malfunction or trouble has occurred by using the latest decision logic 80.

Example embodiments of the present invention have been explained above. However, the present invention is not limited to the example embodiments described above, and a variety of changes can be made without departing from the gist of the present invention.

The marine propulsion device 1 is not limited to the outboard motor, and alternatively, may be another type of propulsion device such as an inboard engine outboard drive or a jet propulsion device. The structure of the marine propulsion device 1 is not limited to that in the example embodiments described above and may be changed. The drive source 10 is not limited to the engine and may be an electric motor.

The status data are not limited to those in the example embodiments described above and may be changed. Determining whether or not the malfunction or trouble of the watercraft 100 has occurred based on the status data is not limited to that in the example embodiments described above and may be changed. For example, the foreign object attachment decision logic 81, the propeller matching decision logic 82, the damper slippage decision logic 83, and the water landing decision logic 84 may be omitted in part. The vessel speed varies with the engine rotational speed. Therefore, the engine rotational speed is used as the load acting on the drive source 10 in the decision logics 81 to 84 described above. However, the vessel speed may be used as the load acting on the drive source 10 instead of the engine rotational speed.

Determining whether or not the malfunction or trouble of the watercraft 100 has occurred based on the status data may not be necessarily made by the watercraft computer 5, and alternatively, may be made by the server 6. In this case, the watercraft computer 5 transmits the status data to the server 6 through the communication device 3. The server 6 stores the decision logic 80 described above. Thus, determining whether or not the malfunction or trouble of the watercraft 100 has occurred is made by the server 6 with reference to the decision logic 80.

According to example embodiments of the present invention, it is possible to determine a malfunction or trouble of a watercraft at an early stage based on a load acting on a drive source.

While example embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.

Claims

1. A control system for a watercraft, the control system comprising: a marine propulsion device including a drive source;a load sensor to detect load data indicating a load acting on the drive source; anda computer configured or programmed to: store a decision logic to determine whether or not a malfunction or trouble of the watercraft has occurred;obtain the load data; anddetermine whether or not the malfunction or trouble of the watercraft has occurred based on the load data with reference to the decision logic; whereinthe decision logic includes at least one of: a foreign object attachment decision logic to determine whether or not attachment of a foreign object to the watercraft has occurred;a propeller matching decision logic to determine whether or not a propeller appropriately matches the marine propulsion device;a damper slippage decision logic to determine whether or not slippage of a propeller damper has occurred in the marine propulsion device; ora water landing decision logic to determine whether or not a water landing of the watercraft has occurred.

2. The control system according to claim 1, wherein the drive source includes an engine;the load sensor includes: an intake pressure sensor to detect an intake pressure of the engine; andan engine speed sensor to detect an engine rotational speed; andthe computer is configured or programmed to: obtain the intake pressure and the engine rotational speed as the load data; anddetermine whether or not the malfunction or trouble of the watercraft has occurred based on the intake pressure and the engine rotational speed.

3. The control system according to claim 1, wherein the computer is configured or programmed to: store initial load data indicating a relationship between a vessel speed of the watercraft and a load acting on the drive source in an initial state of the watercraft;obtain the vessel speed of the watercraft; anddetermine that the attachment of the foreign object to the watercraft has occurred with reference to the foreign object attachment decision logic when the load acting on the drive source during steady navigation of the watercraft is higher than the load indicated by the initial load data by a predetermined value or greater.

4. The control system according to claim 3, wherein the computer is configured or programmed to: obtain cargo data indicating a weight of a cargo on the watercraft; anddetermine whether or not the attachment of the foreign object to the watercraft has occurred with reference to the foreign object attachment decision logic and the cargo data.

5. The control system according to claim 1, wherein the drive source includes an engine;the load sensor includes: an intake pressure sensor to detect an intake pressure of the engine; andan engine speed sensor to detect an engine rotational speed;the computer is configured or programmed to: obtain the intake pressure and the engine rotational speed as the load data; anddetermine that the propeller does not appropriately match the marine propulsion device with reference to the propeller matching decision logic when the intake pressure and the engine rotational speed are plotted outside of a predetermined range in the load data during steady navigation of the watercraft.

6. The control system according to claim 1, wherein the drive source includes an engine;the load sensor includes: an intake pressure sensor to detect an intake pressure of the engine; andan engine speed sensor to detect an engine rotational speed;the computer is configured or programmed to: obtain the intake pressure and the engine rotational speed as the load data; anddetermine that the slippage of the propeller damper has occurred in the marine propulsion device with reference to the damper slippage decision logic when plotting the intake pressure and the engine rotational speed indicates a reduction in the load by a predetermined value or greater.

7. The control system according to claim 1, wherein the drive source includes an engine;the control system further comprises a throttle operator to control an output of the engine;the load sensor includes an engine speed sensor to detect an engine rotational speed; andthe computer is configured or programmed to: obtain the engine rotational speed and an operating amount of the throttle operator as the load data; anddetermine that the water landing of the watercraft has occurred with reference to the water landing decision logic when the engine rotational speed has increased by a predetermined value or greater even though the operating amount of the throttle operator has been kept constant.

8. A method for controlling a watercraft including a marine propulsion device including a drive source, the method comprising: obtaining load data indicating a load acting on the drive source; anddetermining whether or not a malfunction or trouble of the watercraft has occurred based on the load data with reference to a decision logic to determine whether or not the malfunction or trouble of the watercraft has occurred; whereinthe decision logic includes at least one of: a foreign object attachment decision logic to determine whether or not attachment of a foreign object to the watercraft has occurred;a propeller matching decision logic to determine whether or not a propeller appropriately matches the marine propulsion device;a damper slippage decision logic to determine whether or not slippage of a propeller damper has occurred in the marine propulsion device; ora water landing decision logic to determine whether or not a water landing of the watercraft has occurred.

9. The method according to claim 8, wherein the drive source includes an engine, and the method further comprises: obtaining an intake pressure of the engine and an engine rotational speed as the load data; anddetermining whether or not the malfunction or trouble of the watercraft has occurred based on the intake pressure and the engine rotational speed.

10. The method according to claim 8, further comprising: recording initial load data indicating a relationship between a vessel speed of the watercraft and a load acting on the drive source in an initial state of the watercraft;obtaining the vessel speed of the watercraft; anddetermining that the attachment of the foreign object to the watercraft has occurred with reference to the foreign object attachment decision logic when the load acting on the drive source during steady navigation of the watercraft is higher than the load indicated by the initial load data by a predetermined value or greater.

11. The method according to claim 10, further comprising: obtaining cargo data indicating a weight of a cargo loaded on the watercraft; anddetermining whether or not the attachment of the foreign object to the watercraft has occurred with reference to the foreign object attachment decision logic and the cargo data.

12. The method according to claim 8, wherein the drive source includes an engine, and the method further comprises: obtaining an intake pressure of the engine and an engine rotational speed as the load data; anddetermining that the propeller does not appropriately match the marine propulsion device with reference to the propeller matching decision logic when the intake pressure and the engine rotational speed are plotted outside of a predetermined range in the load data during steady navigation of the watercraft.

13. The method according to claim 8, wherein the drive source includes an engine, the method further comprises: obtaining an intake pressure of the engine and an engine rotational speed as the load data; anddetermining that the slippage of the propeller damper has occurred in the marine propulsion device with reference to the damper slippage decision logic when plotting the intake pressure and the engine rotational speed indicates a reduction in the load by a predetermined value or greater.

14. The method according to claim 8, wherein the drive source includes an engine, and the method further comprises: obtaining an engine rotational speed and an operating amount of a throttle operator that controls an output of the engine as the load data; anddetermining that the water landing of the watercraft has occurred with reference to the water landing decision logic when the engine rotational speed has increased by a predetermined value or greater even though the operating amount of the throttle operator has been kept constant.

15. A watercraft comprising: the control system according to claim 1.