SYSTEM FOR AND METHOD OF CONTROLLING WATERCRAFT

A system to control a watercraft including an engine includes a first temperature sensor and a controller. The first temperature sensor is operable to detect a temperature of the engine. The controller is configured or programmed to obtain the temperature of the engine either upon an activation of the controller or a start of the engine. The controller is configured or programmed to estimate an environmental temperature of the watercraft based on the temperature of the engine obtained either upon the activation of the controller or the start of the engine.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese Patent Application No. 2022-015138 filed on Feb. 2, 2022. 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 a system for and a method of controlling a watercraft.

2. Description of the Related Art

There is a type of watercraft embedded with a variety of sensors for detecting environmental conditions thereof. For example, Japan Laid-open Patent Application Publication No. 2008-064720 describes a watercraft embedded with sensors including a wind speed direction meter, an air temperature meter, a water temperature meter, and so forth.

When a watercraft is embedded with sensors dedicated for detecting the environmental conditions thereof as described above, a cost increase is inevitable due to addition of the sensors.

SUMMARY OF THE INVENTION

Preferred embodiments of the present invention provide information about target environmental conditions of watercraft without adding a new sensor.

A system according to a preferred embodiment of the present invention relates to a system for controlling a watercraft including an engine. The system includes a first temperature sensor and a controller. The first temperature sensor is operable to detect a temperature of the engine. The controller is configured or programmed to obtain the temperature of the engine either upon an activation of the controller or a start of the engine. The controller is configured or programmed to estimate an environmental temperature of the watercraft based on the temperature of the engine obtained either upon the activation of the controller or the start of the engine.

A method according to another preferred embodiment of the present invention relates to a method of controlling a watercraft. The watercraft includes an engine and a controller configured or programmed to control the engine. The method includes obtaining a temperature of the engine either upon an activation of the controller or a start of the engine and estimating an environmental temperature of the watercraft based on the temperature of the engine obtained either upon the activation of the controller or the start of the engine.

According to a preferred embodiment of the present invention, the environmental temperature is estimated based on the temperature of the engine obtained either upon the activation of the controller or the start of the engine. The temperature of the engine, obtained either upon the activation of the controller or the start of the engine, approximates the environmental temperature. Therefore, the environmental temperature is accurately obtained with a sensor operable to detect the temperature of the engine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be hereinafter explained with reference to the drawings.FIG.1is a perspective view of a watercraft100according to a preferred embodiment of the present invention. The watercraft100includes a marine propulsion device1and a vessel body2. The marine propulsion device1is attached to the stern of the vessel body2. The marine propulsion device1generates a thrust to propel the watercraft100. In the present preferred embodiment, the marine propulsion device1is an outboard motor.

FIG.2is a side view of the marine propulsion device1. As shown inFIG.2, the marine propulsion device1includes an engine10, a drive shaft11, a propeller shaft12, and a shift mechanism13. The engine10generates the thrust to propel the watercraft100. The engine10includes a crankshaft14. The crankshaft14extends in the vertical direction. The drive shaft11is connected to the crankshaft14. The drive shaft11extends in the vertical direction. The drive shaft11extends downward from the engine10.

The propeller shaft12extends in the back-and-forth direction of the marine propulsion device1. The propeller shaft12is connected to the drive shaft11through the shift mechanism13. A propeller15is connected to the propeller shaft12. The shift mechanism13switches the rotational direction of mechanical power to be transmitted from the drive shaft11to the propeller shaft12. The shift mechanism13includes, for instance, a plurality of gears and a clutch that changes meshing of the gears. The marine propulsion device1is attached to the watercraft100through a bracket16.

The marine propulsion device1includes an ECU (Engine Control Unit)17. The ECU17electrically controls the engine10. The ECU17includes a processor such as a CPU (Central Processing Unit) and memories such as a RAM (Random Access Memory) and a ROM (Read Only Memory).

The marine propulsion device1includes an engine cowl18, an upper case19, and a lower case20. The engine10is disposed inside the engine cowl18. The upper case19is disposed below the engine cowl18. The lower case20is disposed below the upper case19. The drive shaft11is disposed inside the upper case19and the lower case20. The propeller shaft12is disposed inside the lower case20.

The engine10includes a water jacket21. The engine10is cooled by cooling water flowing through the water jacket21. The marine propulsion device1includes a water inlet22, a cooling water pathway23, a discharge water pathway24, and a water pump25. The water inlet22is provided in the lower case20. The cooling water pathway23and the water discharge pathway24are connected to the water jacket21of the engine10. The cooling water pathway23and the water discharge pathway24are disposed inside the upper case19and the lower case20.

The water pump25draws in external water (e.g., seawater) existing outside the marine propulsion device1and supplies the engine10with the drawn in external water as the cooling water. The water pump25takes in the external water through the water inlet22and sends the external water through the cooling water pathway23to the water jacket21of the engine10. The cooling water is discharged from the water jacket21through the water discharge pathway24to the outside of the marine propulsion device1.

FIG.3is a schematic diagram for showing a configuration of a control system3for the watercraft100. As shown inFIG.3, the control system3includes a throttle-shift operating device26. The throttle-shift operating device26is operable by an operator to regulate the rotational speed of the engine10in the marine propulsion device1. The throttle-shift operating device26is also operable by the operator to switch forward movement and rearward movement of the marine propulsion device1.

The throttle-shift operating device26includes a throttle lever27. The throttle lever27is operable from a neutral position to a forward moving position and a rearward moving position. The throttle-shift operating device26outputs a throttle signal indicating the operating position of the throttle lever27. The ECU17receives the throttle signal outputted from the throttle-shift operating device26. The ECU17controls the shift mechanism13in accordance with the operating position of the throttle lever27. Accordingly, the rotation of the propeller shaft12is switched between a forward moving direction and a rearward moving direction. The ECU17controls the engine rotational speed in accordance with the operating position of the throttle lever27.

The control system3includes a steering operating device28and a steering actuator29. The steering actuator29turns the marine propulsion device1right and left so as to change the rudder angle of the marine propulsion device1. The steering actuator29includes, for instance, an electric motor. Alternatively, the steering actuator29may include an electric pump and a hydraulic cylinder.

The steering operating device28is operable by the operator to adjust the rudder angle of the marine propulsion device1. The steering operating device28includes, for instance, a steering wheel. Alternatively, the steering operating device28may be another type of operating device such as a joystick. The steering operating device28is operable right and left from a neutral position. The steering operating device28outputs a steering signal indicating the operating position thereof. The steering actuator29is controlled in accordance with the operating position of the steering operating device28, such that the rudder angle of the marine propulsion device1is controlled.

The control system3includes a display31and an input device32. The display31displays information regarding the marine propulsion device1. The display31displays an image in response to an image signal inputted thereto. The input device32receives an operational input from a user. The input device32outputs an input signal indicating the operational input by the user. The input device32includes, for instance, a touchscreen. It should be noted that the input device32may include at least one hardware key.

The control system3includes an intake air temperature sensor34, a wall temperature sensor35, a cooling water temperature sensor36, and an intake air pressure sensor37. The intake air temperature sensor34, the wall temperature sensor35, the cooling water temperature sensor36, and the intake air pressure sensor37are provided in the marine propulsion device1. The intake air temperature sensor34outputs a signal indicating intake air temperature data. The intake air temperature data indicates the intake air temperature of the engine10. The wall temperature sensor35outputs a signal indicating wall temperature data. The wall temperature data indicates the wall temperature of the engine10. The wall temperature of the engine10includes, for instance, the temperature of the wall surface of the combustion chamber in the engine10. The cooling water temperature sensor36outputs a signal indicating cooling water temperature data. The cooling water temperature data indicates the temperature of the cooling water flowing through the water jacket21of the engine10. The intake air pressure sensor37outputs a signal indicating intake air pressure data. The intake air pressure data indicates the intake air pressure of the engine10.

The control system3includes a watercraft operating controller38and a data communication module (hereinafter referred to as DCM)39. The watercraft operating controller38includes a processor such as a CPU, memories such as a RAM and a ROM, and a storage such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive). The watercraft operating controller38stores programs and data to control the marine propulsion device1. The watercraft operating controller38is connected to the ECU17through wired or wireless communication. The watercraft operating controller38is connected to the throttle-shift operating device26and the steering operating device28through wired or wireless communication.

The control system3includes a main switch33. The main switch33is operable by the operator. When the main switch33is turned on, the watercraft operating controller38is activated. When the main switch33is turned on, the engine10is started.

The watercraft operating controller38receives the input signal outputted from the input device32. The watercraft operating controller38initiates the control of the marine propulsion device1in response to the input signal. The watercraft operating controller38outputs the image signal to the display31and causes the display31to display the information regarding the marine propulsion device1.

The watercraft operating controller38obtains the intake air temperature data from the intake air temperature sensor34. The watercraft operating controller38obtains the wall temperature data from the wall temperature sensor35. The watercraft operating controller38obtains the cooling water temperature data from the cooling water temperature sensor36. The watercraft operating controller38obtains the intake air pressure data from the intake air pressure sensor37. The watercraft operating controller38records the intake air temperature data, the wall temperature data, the cooling water temperature data, and the intake air pressure data at predetermined intervals of time.

The watercraft operating controller38determines an occurrence of malfunctioning or abnormality of the engine10based on the intake air temperature data, the wall temperature data, the cooling water temperature data, or the intake air pressure data. For example, the watercraft operating controller38determines an occurrence of overheating of the engine10based on the cooling water temperature data. For example, the watercraft operating controller38determines that overheating of the engine10is occurring when the temperature of the cooling water is greater than or equal to a predetermined threshold of temperature. When it is determined that malfunctioning or abnormality of the engine10is occurring, the watercraft operating controller38causes the display31to display an alert. Alternatively, when it is determined that malfunctioning or abnormality of the engine10is occurring, the watercraft operating controller38may turn on a warning lamp.

The DCM39performs wireless communication with an external computer. The DCM39includes a processor such as a CPU, memories such as a RAM and a ROM, and an auxiliary storage device such as an HDD or an SSD. The DCM39is capable of performing data transmission with the external computer through a mobile communication network200. The mobile communication network200is, for instance, a network of a 3G, 4G, or 5G mobile communication system.

The DCM39is communicable with a server201. The DCM39is communicable with a user terminal202. The user terminal202may be, for instance, a smartphone, a tablet, or a personal computer. The DCM39may be communicable with the user terminal202through the server201.

The DCM39collects watercraft data regarding the watercraft100and sends the collected watercraft data to the server201. The DCM39sends the watercraft data to the server201at predetermined intervals of time. The watercraft data includes the aforementioned data, i.e., the intake air temperature data, the wall temperature data, the cooling water temperature data, and the intake air pressure data.

The watercraft operating controller38obtains a temperature of the engine10upon a start of the engine10and estimates an environmental temperature of the watercraft100based on the temperature of the engine10obtained upon the start of the engine10. For example, the watercraft operating controller38estimates an external temperature based on an intake air temperature obtained upon the start of the engine10. The watercraft operating controller38estimates a temperature of the external water based on a temperature of the cooling water obtained upon the start of the engine10.

FIG.4is a flowchart of a series of processes for estimating an external air temperature. As shown inFIG.4, in step S101, the watercraft operating controller38obtains an intake air temperature of the engine10upon a start of the engine10. The watercraft operating controller38obtains, from the intake air temperature data, the intake air temperature of the engine10upon the start of the engine10. The watercraft operating controller38obtains an intake air temperature of the engine10upon a turn-on operation of the main switch33as the intake air temperature of the engine10upon the start of the engine10.

In step S102, the watercraft operating controller38obtains a length of elapsed time from a previous stop of the engine10to a current start of the engine10. The watercraft operating controller38stores a set of date and clock time of each start of the engine10and each stop of the engine10. For example, the watercraft operating controller38stores a set of date and clock time upon a turn-off operation of the main switch33. The watercraft operating controller38stores a set of date and clock time upon a turn-on operation of the main switch33. The watercraft operating controller38calculates the length of elapsed time based on the set of date and clock time stored upon the turn-on operation of the main switch33and upon the turn-off operation of the main switch33.

In step S103, the watercraft operating controller38determines whether or not the length of elapsed time is greater than or equal to a length-of-time threshold A1. The length-of-time threshold A1is defined as, for instance, a length of time enough for the temperature of the engine10to sufficiently reduce to a temperature close to the external air temperature after the stop of the engine10. When the length of elapsed time is greater than or equal to the length-of-time threshold A1, the process proceeds to step S104.

In step S104, the watercraft operating controller38estimates the external air temperature based on the intake air temperature obtained upon the start of the engine10. The watercraft operating controller38sets the value of the intake air temperature obtained upon the start of the engine10as the external air temperature.

FIG.5is a flowchart of a series of processes for estimating an external water temperature. As shown inFIG.5, in step S201, the watercraft operating controller38obtains a temperature of the cooling water for the engine10upon a start of the engine10. The watercraft operating controller38obtains, from the cooling water temperature data, the temperature of the cooling water for the engine10upon the start of the engine10. The watercraft operating controller38obtains a temperature of the cooling water for the engine10upon a turn-on operation of the main switch33as the temperature of the cooling water for the engine10upon the start of the engine10.

In step S202, the watercraft operating controller38obtains a length of elapsed time from a previous stop of the engine10to a current start of the engine10in a similar manner to step S102.

In step S203, the watercraft operating controller38determines whether or not the length of elapsed time is greater than or equal to a length-of-time threshold A2. The length-of-time threshold A2is defined as, for instance, a length of time enough for the temperature of the engine10to sufficiently reduce to a temperature close to an external air temperature after the stop of the engine10. When the length of elapsed time is greater than or equal to the length-of-time threshold A2, the process proceeds to step S204.

In step S204, the watercraft operating controller38estimates the external water temperature based on the temperature of the cooling water obtained upon the start of the engine10. The watercraft operating controller38sets the value of the temperature of the cooling water obtained upon the start of the engine10as the external water temperature.

FIG.6is a flowchart of a series of processes for estimating an atmospheric pressure. As shown inFIG.6, in step S301, the watercraft operating controller38obtains an intake air pressure of the engine10upon a start of the engine10. The watercraft operating controller38obtains, from the intake air pressure data, the intake air pressure of the engine10upon the start of the engine10. The watercraft operating controller38obtains an intake air pressure of the engine10upon a turn-on operation of the main switch33as the intake air pressure of the engine10upon the start of the engine10.

In step S302, the watercraft operating controller38obtains a length of elapsed time from a previous stop of the engine10to a current start of the engine10in a similar manner to step S102.

In step S303, the watercraft operating controller38determines whether or not the length of elapsed time is greater than or equal to a length-of-time threshold A3. The length-of-time threshold A3is defined as, for instance, a length of time enough for the temperature of the engine10to sufficiently reduce to a temperature close to an external air temperature after the stop of the engine10. When the length of elapsed time is greater than or equal to the length-of-time threshold A3, the process proceeds to step S304.

In step S304, the watercraft operating controller38estimates the atmospheric pressure based on the intake air pressure obtained upon the start of the engine10. The watercraft operating controller38sets the value of the intake air pressure obtained upon the start of the engine10as the atmospheric pressure.

As described above, the watercraft operating controller38estimates the external air temperature, the external water temperature, and the atmospheric pressure. The watercraft operating controller38may send the estimated external temperature, external water temperature, and atmospheric pressure as the watercraft data to the server201. The watercraft operating controller38may determine malfunctioning or abnormality of the marine propulsion device1or of the watercraft100based on the estimated external air temperature, external water temperature, and atmospheric pressure. The watercraft operating controller38may cause the display31to display the estimated external air temperature, external water temperature, or atmospheric pressure.

In the control system3for the watercraft100according to a preferred embodiment of the present invention, the external air temperature is estimated based on the intake air temperature of the engine10obtained upon the start of the engine10. The intake air temperature of the engine10obtained upon the start of the engine10is approximate to the external air temperature. Therefore, the external air temperature is accurately estimated with the intake air temperature sensor34.

The external water temperature is estimated based on the temperature of the cooling water for the engine10obtained upon the start of the engine10. The temperature of the cooling water for the engine10obtained upon the start of the engine10is approximate to the external water temperature. Therefore, the external water temperature is accurately estimated with the cooling water temperature sensor36.

The atmospheric pressure is estimated based on the intake air pressure of the engine10obtained upon the start of the engine10. The intake air pressure of the engine10obtained upon the start of the engine10is approximate to the atmospheric pressure. Therefore, the atmospheric pressure is accurately estimated with the intake air pressure sensor37.

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

The marine propulsion device1is 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 device1is not limited to that in the preferred embodiments described above and may be changed. The structure of the control system3is not limited to that in the preferred embodiments described above and may be changed. For example, the DCM39may be omitted.

The series of processes for estimating the external air temperature, the external water temperature, or the atmospheric pressure are not limited to those in the preferred embodiments described above and may be changed. For example,FIG.7is a flowchart of a series of processes for estimating an external air temperature according to a modification.

As shown inFIG.7, a process step of S401is similar to that of S101described above. In step S402, the watercraft operating controller38obtains a wall temperature of the engine10upon the start of the engine10. The watercraft operating controller38obtains, from the wall temperature data, the wall temperature of the engine10upon the start of the engine10. The watercraft operating controller38obtains a wall temperature of the engine10upon a turn-on operation of the main switch33as the wall temperature of the engine10upon the start of the engine10.

In step S403, the watercraft operating controller38determines whether or not a temperature difference between the wall temperature and the intake air temperature is less than or equal to a temperature threshold B1. When the temperature difference between the wall temperature and the intake air temperature is less than or equal to the temperature threshold B1, the process proceeds to step S404. In step S404, the watercraft operating controller38estimates the external air temperature based on the intake air temperature obtained upon the start of the engine10in a similar manner to step S104.

Likewise, in the series of processes for estimating the external water temperature shown inFIG.5, the process steps of S402and S403may be executed instead of those of S202and S203. Still likewise, in the series of processes for estimating the atmospheric pressure shown inFIG.6, the process steps of S402and S403may be executed instead of those of S302and S303.

When the watercraft operating controller38has been activated but the engine10has been stopped, the watercraft operating controller38may estimate an environmental temperature of the watercraft100based on a temperature of the engine10to be obtained upon the activation of the watercraft operating controller38. For example, the watercraft operating controller38may estimate an external air temperature based on an intake air temperature to be obtained upon the activation of the watercraft operating controller38. The watercraft operating controller38may estimate an external water temperature based on a temperature of the cooling water to be obtained upon the activation of the watercraft operating controller38. The watercraft operating controller38may estimate an atmospheric pressure based on an intake air pressure of the engine10to be obtained upon the activation of the watercraft operating controller38.

Estimation of the external air temperature, the external water temperature, and the atmospheric pressure may not be necessarily executed by the watercraft operating controller38, and instead, may be executed by another computer. For example, estimation of the external air temperature, the external water temperature, and the atmospheric pressure may be executed by the server201.