Personal water craft and control method for the same

Abstract

To provide a personal watercraft capable of suppressing skidding.SOLUTION: A personal watercraft 10 has: a hull 11; an engine 12; a steering device 13; a water injection nozzle 14; a control unit 15; a throttle mechanism 16; and a detector 21 having a six-axis sensor 20. Angular velocity and angular acceleration around a yawing axis is detected by the six-axis sensor 20 when the hull 11 is rotated. Deceleration control is carried out by the control unit 15 to decelerate the engine 12 when at least one of the angular velocity and the angular acceleration exceeds a threshold value.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to personal watercraft such as water bikes and small outboard boats, and a control method thereof.

Background Art

[0002] As an example of personal watercraft (abbreviated as PWC), small boats also called water bikes and jet boats are known. In particular, personal watercraft that advance by jet propulsion can not only travel at high speed, but also have a small turning radius and can change the boat speed nimbly. For this reason, personal watercraft are excellent in maneuverability and agility, and are expected to be active in various situations. For example, in the field of water leisure, not only normal running but also acrobatic boating is possible.

[0003] In this specification, "turning" includes a course change in which the direction of the hull changes by nearly 180° like a U-turn, but also includes a concept in which the course changes at other angles. For example, it includes a full rotation exceeding 360°, a turn of an angle less than 360° or an obtuse angle of 90° or less. In short, in this specification, a course change that may cause skidding is called turning.

[0004] When turning a personal watercraft at high speed, skidding may occur. The factors causing skidding are not only the boat speed and turning radius. For example, it is also affected by sea conditions such as wave conditions, wind, and tidal currents. For this reason, even if the boat speed and turning radius are the same, depending on the sea conditions, skidding may or may not occur. Once skidding occurs, the hull may face an unintended direction, the hull may spin, or it may make a large turn without being able to complete a curve. Also, when skidding occurs, the operator may lose their balance, or the attitude of the hull may change significantly.

[0005] FIG. 8 is a plan view schematically showing examples of three types of trajectories when a conventional personal watercraft turns. Trajectory M1 in FIG. 8 shows the case where the hull 1 turns normally without experiencing sideslip. Trajectory M2 shows that the hull 1 experiences sideslip and the degree of sideslip gradually increases, resulting in a spin and loss of control. Trajectory M3 shows that the hull 1 turns in a large circle while maintaining a sideslip attitude. Sideslip is also affected by the skill of the operator and sea conditions such as waves. Although a certain degree of sideslip is acceptable, it is desirable to suppress large sideslip.

[0006] Small boats equipped with additional configurations such as attaching sponsons to the sides of the hull or controlling trim tabs are also known in order to stabilize the attitude of the hull during travel. However, such small boats equipped with these additional configurations can achieve stable travel but will suppress agile turning. It is not impossible to strike a balance between stability and maneuverability by changing the size and shape of the sponsons. However, it is difficult to use such additional configurations flexibly according to the purpose of use and sea conditions.

[0007] The small boat described in Patent Document 1 has means for suppressing sideslip during turning. The small boat controls the discharge duct of jet propulsion according to the amount of rotation of the steering device. For example, a control valve is provided in the discharge duct and the control valve is operated by valve drive means interlocked with the steering device.

[0008] The small boat described in Patent Document 2 detects the engine speed or throttle opening degree and controls the trim angle based on the detected signal. For example, at the start of turning, the deflector is actuated by a trim actuator to reduce the trim angle of the hull, thereby suppressing an increase in the turning radius.

[0009] The jet boat described in Patent Document 3 has a turning state determination unit for determining the turning state of the hull. The turning state determination unit detects the turning state of the hull based on the operation angle of the steering wheel, the traveling speed, the engine speed, etc. When it is determined that the turning state is during high-speed travel, the engine speed is decreased.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0011] Conventional small boats described in Patent Documents 1-3, etc. predict the occurrence of skidding based on data such as the operation angle of the steering device, the engine speed, and the ship speed. However, skidding is affected by sea conditions such as wave conditions, wind, and tidal currents. For example, skidding may occur depending on the wave and wind conditions hitting the hull during turning.

[0012] Therefore, even if skidding is predicted based on the operation angle of the steering device, the engine speed, the ship speed, etc., it is impossible to cope with the constantly changing sea conditions, and unexpected skidding may occur. On the other hand, if control is performed to suppress skidding uniformly regardless of the skill of the operator and the sea conditions, the ship speed during turning will decrease more than necessary, or the turning radius will increase, which is not preferable.

[0013] As another conventional example, a small boat equipped with a capsizing sensor has also been proposed. When the hull of a small boat equipped with a capsizing sensor loses control and capsizes due to skidding or the like, a signal to stop the engine is output from the sensor that has detected the capsizing. However, even if it is equipped with a capsizing sensor, it is not possible to suppress skidding.

[0014] An object of an embodiment of the present invention is to provide a personal watercraft that can suppress skidding that occurs when steering is operated and that does not suppress the boat speed during turning more than necessary, and a control method therefor.

Means for Solving the Problems

[0015] One embodiment is a personal watercraft including a hull, an engine mounted on the hull, a fuel supply mechanism such as a throttle mechanism for controlling the rotation of the engine, and a steering device for steering. The fuel supply mechanism may be a fuel injection system including a fuel injection valve and a fuel injection pump or the like. Further, this personal watercraft includes a detection unit and a control unit. The detection unit has a sensor that detects at least one of the angular velocity and the angular acceleration around the yaw axis of the hull. When the angular velocity or the angular acceleration around the yaw axis detected by the detection unit exceeds a threshold value during turning of the hull, the control unit performs deceleration control of the engine.

[0016] In the personal watercraft of this embodiment, when the hull is turning in the same direction, the control unit may perform the first deceleration control based on the angular acceleration, and perform the subsequent deceleration controls during turning in the same direction as the first time based on the angular velocity. Further, the detection unit may have a six-axis sensor that detects the angular velocity and the angular acceleration in the roll direction, the angular velocity and the angular acceleration in the pitch direction, and the angular velocity and the angular acceleration around the yaw axis. The control unit may perform the deceleration control based on at least one of the angular velocity and the angular acceleration around the yaw axis.

[0017] The control method of a personal watercraft according to an embodiment of the present invention detects at least one of the angular velocity and the angular acceleration about the yaw axis in a state where the hull is turning, and when the detected angular velocity or angular acceleration exceeds a threshold value, performs deceleration control to decelerate the engine. In the control method of this embodiment, the angular velocity and the angular acceleration about the yaw axis of the hull are detected, the first deceleration control when the hull is turning in the same direction is performed based on the angular acceleration, and when the hull is turning in the same direction as the first time, the deceleration control after the second time may be performed based on the angular velocity.

Advantages of the Invention

[0018] According to the personal watercraft and its control method according to the present invention, it is possible to suppress skidding generated during turning and avoid the ship speed during turning from being suppressed more than necessary.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0020] [First Embodiment] Hereinafter, a personal watercraft according to the first embodiment and its control method will be described with reference to FIGS. 1 to 4. FIG. 1 shows a personal watercraft 10 (sometimes referred to as a water scooter) as an example of a small ship. FIG. 2 is a side view of the personal watercraft 10.

[0021] The personal watercraft 10 of the present embodiment includes a hull 11, an engine 12 mounted on the hull 11, a steering device 13 for steering, a water injection nozzle 14, a control unit (controller) 15, a throttle mechanism 16, a detection unit 21 including a six-axis sensor 20, and the like. The water injection nozzle 14 is disposed at the rear of the hull 11. The control unit 15 includes an electric circuit for controlling the engine 12. The throttle mechanism 16 is an example of a fuel supply mechanism. Another example of the fuel supply mechanism may be a fuel injection system including a fuel injection valve and a fuel injection pump.

[0022] When the impeller rotates by the engine 12, a water flow for jet propulsion is jetted into the water from the water injection nozzle 14. The throttle mechanism 16 controls the rotation of the engine 12. That is, if the opening degree of the throttle mechanism 16 (referred to as the throttle opening degree) is large, the engine 12 rotates at a high speed, and if the throttle opening degree is small, the engine 12 rotates at a low speed. In the case of an engine using a fuel injection valve, the engine 12 rotates at a low speed by reducing the fuel injection amount. As an example of engine deceleration control, fuel cut or ignition cut may be applied.

[0023] The steering device 13 includes a steering wheel 13a and a steering cable 30 for transmitting the movement of the steering wheel 13a to the water injection nozzle 14. When the steering wheel 13a is operated to the right or left, the direction of the water injection nozzle 14 changes via the steering cable 30, and the direction of the hull 11 can be changed. The direction and the operation angle in which the steering wheel 13a is operated are detected by a steering sensor 31 (shown in FIG. 1).

[0024] An accelerator operation unit 32 for operating the accelerator and an accelerator sensor 33 are provided on the steering wheel 13a. When the accelerator operation unit 32 is manually operated, a signal for controlling the accelerator opening degree is output from the accelerator sensor 33 to the control unit 15 according to the operation amount. The control unit 15 changes the accelerator opening degree of the throttle mechanism 16 based on the accelerator control signal.

[0025] The detection unit 21 has a six-axis sensor 20. As shown in FIG. 1, the six-axis sensor 20 has a function of detecting the acceleration in each axial direction and the angular velocity around the axis with respect to the X-axis, Y-axis, and Z-axis that are orthogonal to each other. That is, the six-axis sensor 20 detects the acceleration in the X-axis direction and the angular velocity around the X-axis, the acceleration in the Y-axis direction and the angular velocity around the Y-axis, and the acceleration in the Z-axis direction and the angular velocity around the Z-axis. An electrical signal regarding the acceleration detected by the six-axis sensor 20 and an electrical signal regarding the angular velocity are input to the control unit 15.

[0026] The X-axis of the six-axis sensor 20 extends in the longitudinal direction of the hull 11. That is, the rotation around the X-axis is the direction in which the hull 11 rolls (roll direction). The Y-axis extends in the width direction of the hull 11. The rotation around the Y-axis is the direction in which the hull 11 pitches (pitch direction). The Z-axis extends in the vertical direction of the hull 11. The rotation around the Z-axis is the yaw direction of the hull 11. In this specification, the rotation in the yaw direction may be referred to as the rotation around the yaw axis.

[0027] FIG. 3 is a time chart showing an example of the relationship between various electrical signals and time when the personal watercraft 10 of the present embodiment travels. The details of items (1) to (5) in FIG. 3 are as follows. (1) [Steering] indicates the steering direction (right or left) detected by the steering sensor 31 when the steering handle 13a is operated. (2) [Angular velocity] indicates the change over time of the angular velocity in the yaw direction (around the Z axis) detected by the 6-axis sensor 20 when the hull 11 turns. (3) [Angular acceleration] indicates the change over time of the angular acceleration calculated from the angular velocity in the yaw direction (around the Z axis) detected by the 6-axis sensor 20 when the hull 11 turns. (4) [Throttle opening] indicates the change over time of the throttle control signal output from the control unit 15 to the engine 12 in a state where the throttle operation unit 32 is operated by the operator. However, the operation amount of the throttle operation unit 32 and the throttle control signal output from the control unit 15 to the engine 12 may be different. (5) [Engine speed opening] indicates the change over time of the rotational speed of the engine 12.

[0028] Next, an example of the control method of the personal watercraft 10 of the present embodiment will be described with reference to FIGS. 3 and 4. FIG. 4 is a flowchart showing the flow of the skid suppression process of the personal watercraft 10 according to the first embodiment. The skid suppression process is performed based on a computer program stored in the control unit 15 and the output of the 6-axis sensor 20 and the like.

[0029] In step ST1 in FIG. 4, the steering is approximately in the neutral position, and the personal watercraft 10 is traveling almost straight ahead. In step ST2, the steering handle 13a is operated to the right or left by the operator.

[0030] For example, as shown by R1 in (1) [Steering] of FIG. 3, when the steering wheel 13a is operated to the right, the hull 11 turns to the right. During this turning, as shown in (2) [Angular velocity] of FIG. 3, an angular velocity is generated, and as shown in (3) [Angular acceleration], an angular acceleration is generated. The rise of the angular acceleration is faster than the rise of the angular velocity. Moreover, when a skid occurs on the hull 11 during turning, a larger angular velocity and angular acceleration are generated compared to when no skid occurs.

[0031] In step ST3 in FIG. 4, an angular velocity is detected and an angular acceleration is detected, and the process proceeds to step ST4. In step ST4, it is determined whether the angular acceleration exceeds a first threshold value TH1. If the angular acceleration exceeds the first threshold value TH1 (in step ST4, “YES”), the process proceeds to step ST6. In step ST6, a signal for reducing the throttle opening is output from the control unit 15 to the engine 12, and thus deceleration control of the engine 12 is performed. As an example of engine deceleration control, ignition cut may be applied. In the case of an engine using a fuel injection valve, control for reducing the fuel injection amount or fuel cut may be performed.

[0032] If the angular acceleration does not exceed the first threshold value TH1 (in step ST4, “NO”), the process proceeds to step ST5. In step ST5, it is determined whether the angular velocity exceeds a second threshold value TH2. If the angular velocity exceeds the second threshold value TH2 (in step ST5, “YES”), the process proceeds to step ST6. In step ST6, a signal for reducing the throttle opening is output from the control unit 15 to the engine 12, and thus deceleration control of the engine 12 is performed.

[0033] In step ST6, as shown in (4) [Accelerator opening] of FIG. 3, for example, deceleration control for approaching the throttle opening to zero is executed. When the throttle opening approaches zero, the engine speed rapidly decreases in step ST7. Therefore, as shown in (5) [Engine speed] of FIG. 3, as the engine speed approaches zero, the thrust decreases and the skid is suppressed.

[0034] In step ST8 in FIG. 4, when the steering handle 13a is returned to the neutral position (”YES” in step ST8), the skid suppression process ends. If the steering handle 13a has not been returned to the neutral position (”NO” in step ST8), the process returns to step ST3, and the skid suppression process from step ST3 to step ST7 is repeated.

[0035] As shown by L1 in (1) [Steering] of FIG. 3, when the steering handle 13a is operated to the left, the hull 11 turns counterclockwise. Also at this time, the skid suppression process shown from step ST3 to step ST7 in FIG. 4 is performed, and the skid during counterclockwise turning is suppressed in the same manner as during clockwise turning.

[0036] Once skidding has occurred and the hull has become unstable, it may be difficult to deal with the skid. Therefore, the inventors focused on the fact that the rise of the angular acceleration at the time of skid occurrence is faster than the rise of the angular velocity. That is, in step ST4, the rise of the angular acceleration at the start of skidding is detected. If the angular acceleration exceeds the first threshold value TH1, the process proceeds to the deceleration control after step ST6. For this reason, deceleration control can be started before the skid becomes large. However, depending on the situation, the process may proceed to the deceleration control in step ST6 based on the magnitude of the angular velocity as in step ST5.

[0037] A comparative example shown in FIG. 5 will be described for reference. FIG. 5 is a time chart of a comparative example considered by the inventors in the process of developing a personal watercraft. This comparative example personal watercraft also has a six-axis sensor and detects the angular velocity and angular acceleration, but the skid suppression process as described in the first embodiment is not performed. Incidentally, this comparative example was considered confidentially and is not publicly known.

[0038] Since items (1) to (5) in FIG. 5 are common to FIG. 3, the description of items (1) to (5) is omitted. As shown by R1 in (1) [Steering] of FIG. 5, when the steering wheel is operated to the right, the hull turns to the right. During this turning, as shown in (2) [Angular Velocity] of FIG. 5, an angular velocity is generated, and as shown in (3) [Angular Acceleration], an angular acceleration is generated. In particular, when sideslip occurs during turning, a large angular velocity and angular acceleration are generated.

[0039] In (4) [Throttle Opening] of FIG. 5, for example, in the case of cruise control, the throttle opening is kept constant. When sideslip occurs and the inclination of the hull in the rolling direction increases, the position of the water intake for jet propulsion deteriorates compared to normal. Therefore, as shown at times t1 and t2 in (5) [Engine Speed] of FIG. 5, the engine tends to idle and a temporary engine surge occurs. In this comparative example, since no sideslip suppression process is performed, there is a risk that the balance of the hull or the operator may be disrupted or an engine surge may occur.

[0040] [Second Embodiment] The control method of a personal watercraft according to the second embodiment will be described below with reference to FIGS. 6 and 7. The components of the personal watercraft of the second embodiment may be the same as those of the personal watercraft 10 (shown in FIGS. 1 and 2) of the first embodiment. Therefore, in the second embodiment, the same reference numerals are given to the components common to the personal watercraft 10 of the first embodiment and the description thereof is omitted. The personal watercraft of the second embodiment also has a six-axis sensor 20.

[0041] FIG. 6 is a time chart showing an example of the relationship between various electrical signals and time when the personal watercraft of the second embodiment turns. Explaining in order from the top of FIG. 6, line segment A [Steering] indicates the steering direction (right or left) detected by the steering sensor 31 when the steering wheel 13a is operated.

[0042] In FIG. 6, line segment B [angular velocity] shows the change over time of the absolute value of the angular velocity in the yaw direction (rotation about the Z-axis) detected by the six-axis sensor 20 when the hull turns. Line segment C [angular acceleration] shows the change over time of the absolute value of the angular acceleration calculated from the angular velocity in the yaw direction (rotation about the Z-axis) detected by the six-axis sensor 20 when the hull turns.

[0043] In FIG. 6, line segment D [throttle opening] shows the change over time of the throttle control signal output from the control unit 15 to the engine 12 in a state where the throttle operation unit 32 is operated by the operator. However, the operation amount of the throttle operation unit 32 and the throttle control signal output by the control unit 15 to the engine 12 may be different. Line segment E [engine speed] shows the change over time of the rotational speed of the engine 12.

[0044] FIG. 7 is a flowchart showing the flow of the skid suppression process of the personal watercraft according to the second embodiment. The skid suppression process is performed based on the computer program stored in the control unit 15 and the output of the six-axis sensor 20 and the like.

[0045] In step ST10 in FIG. 7, the steering is approximately in the neutral position, and the personal watercraft 10 is moving straight ahead. In step ST11, the steering wheel 13a is operated to the right or left by the operator.

[0046] For example, as indicated by R2 in line segment A [steering] in FIG. 6, when the steering wheel 13a is operated to the right, the hull turns to the right. During this turn, an angular velocity is generated as shown by line segment B [angular velocity], and an angular acceleration is generated as shown by line segment C [angular acceleration]. The rise of the angular acceleration is earlier than the rise of the angular velocity. Moreover, when a skid occurs on the hull 11 during the turn, a larger angular velocity and angular acceleration are generated compared to when no skid occurs.

[0047] In step ST12 in FIG. 7, the angular velocity is detected and the angular acceleration is detected, and the process proceeds to step ST13. In step ST13, it is determined whether the angular acceleration exceeds a first threshold value TH1. If the angular acceleration exceeds the first threshold value TH1 (in step ST13, “YES”), the process proceeds to step ST14. In step ST14, it is determined whether it is the “first deceleration control” during turning in the same direction. If it is the first deceleration control (in step ST14, “YES”), the process proceeds to step ST16, and deceleration control is performed. If it is the second or subsequent deceleration control during turning in the same direction (in step ST14, “NO”), the process proceeds to step ST15.

[0048] If the angular acceleration does not exceed the first threshold value TH1 in step ST13 (in step ST13, “NO”), the process proceeds to step ST15. In step ST15, it is determined whether the angular velocity exceeds a second threshold value TH2. If the angular velocity exceeds the second threshold value TH2 (in step ST15, “YES”), the process proceeds to step ST16, and deceleration control is performed.

[0049] In step ST16, as shown by line segment D [throttle opening] in FIG. 6, for example, deceleration control is executed to bring the throttle opening close to zero. When the throttle opening approaches zero, the engine speed rapidly decreases in step ST17. For this reason, as shown by line segment E [engine speed] in FIG. 6, as the engine speed approaches zero, the thrust decreases and the skid is suppressed.

[0050] In step ST18 in FIG. 7, it is determined whether the steering wheel 13a has been returned to the neutral position. If the steering wheel 13a has not been returned to the neutral position (in step ST18, “NO”), the process returns to step ST12, and the skid suppression process up to step ST17 is repeated.

[0051] In the example shown in FIG. 6, first, the steering wheel was operated to the right, and the hull made a right turn. During this right turn, since the first threshold value TH1 was exceeded at P1 of the line segment C [angular acceleration], the first deceleration control was performed. After that, since the second threshold value TH2 was exceeded at P2 and P3 of the line segment B [angular velocity], the second and third deceleration controls during the right turn were performed. That is, as shown in the line segment D [throttle opening], a total of three deceleration controls G1, G2, and G3 were performed during the right turn.

[0052] In step ST18 in FIG. 7, when it is determined that the steering wheel 13a has been returned to the neutral position (”YES” in step ST18), the skid suppression process ends. Then, it waits until the steering wheel 13a is operated during the next turn.

[0053] For example, after the steering wheel is returned to the neutral position, as shown by L2 in the line segment A [steering] of FIG. 6, when the steering wheel is operated to the left, the hull makes a left turn. During this left turn, since the first threshold value TH1 was exceeded at P4 of the line segment C [angular acceleration], the first deceleration control during the left turn was performed. After that, since the second threshold value TH2 was exceeded at P5, P6, and P7 of the line segment B [angular velocity], the deceleration controls after the second time during the left turn were performed. That is, as shown in the line segment D [throttle opening], four deceleration controls G4, G5, G6, and G7 were performed during the left turn.

[0054] Thus, in the skid suppression process of the second embodiment, the first deceleration control performed during a turn in the same direction proceeds to step ST16, and the deceleration control based on the angular acceleration is performed. Therefore, the thrust can be reduced at the time when skidding starts to occur, and skidding can be effectively suppressed. For the deceleration controls after the second time, since the ship speed has been reduced to a certain extent by the first deceleration control, it proceeds to step ST15, and the deceleration control based on the angular velocity is performed.

[0055] When comparing the waveform of line segment B [angular velocity] shown in FIG. 6 with the waveform of line segment C [angular acceleration], the change in angular acceleration is more drastic than the change in angular velocity. For this reason, if the deceleration control for the second time and subsequent times during turning in the same direction is performed based on the angular acceleration, the engine speed will change frequently, making it difficult to control the hull.

[0056] Therefore, in the skid suppression process of the second embodiment, the first deceleration control performed during turning in the same direction is performed based on the angular acceleration, and the deceleration control for the second time and subsequent times is performed based on the angular velocity. As a result, it was possible to avoid the engine speed from changing more than necessary during turning. Moreover, it became possible to perform the deceleration control at the initial stage of skidding.

[0057] [Other Embodiments] In a personal watercraft equipped with a six-axis sensor 20, at least one of the angular velocity and angular acceleration around the X-axis (roll direction) may be detected and used for the aforementioned skid suppression process. For example, in the skid suppression process described in the second embodiment, information on the angular velocity or angular acceleration in the roll direction may be taken into account. Alternatively, the angular velocity and angular acceleration around the Y-axis (pitch direction) may be detected and used for the aforementioned skid suppression process.

[0058] In addition to the information on the roll and pitch of the hull, the speed of the hull may be detected and used for the aforementioned skid suppression process (trigger for deceleration control). Also, these pieces of information (roll, pitch, hull speed) and angular velocity and angular acceleration may be combined to perform the aforementioned skid suppression process. For example, the threshold value of angular acceleration (first threshold value TH1) and the threshold value of angular velocity (second threshold value TH2) may be changed according to the information on pitch, roll, and hull speed.

[0059] In a personal watercraft equipped with sponsons for stabilizing the hull, a movable sponson may be adopted. In that case, the amount of protrusion of the sponson may be changed so as to suppress skidding according to the magnitude of the angular velocity or angular acceleration detected by a six-axis sensor or the like during turning.

[0060] Personal watercrafts equipped with movable trim tabs are also known. In a personal watercraft equipped with movable trim tabs, the inclination of the trim tab may be changed so as to suppress skidding according to the magnitude of the angular velocity or angular acceleration detected by a six-axis sensor or the like during turning.

[0061] In practicing the present invention, the detection unit is not limited to a six-axis sensor, and a sensor capable of detecting at least the angular velocity and angular acceleration in the yaw direction may be used. Needless to say, components of the personal watercraft such as the hull, engine, and steering device can also be changed as necessary. The skidding suppression process of the present invention may be applied to outboard motor boats.

Explanation of Reference Numerals

[0062] 10…Personal watercraft, 11…Hull, 12…Engine, 13…Steering device, 13a…Steering handle, 14…Water injection nozzle, 15…Control unit, 16…Throttle mechanism (fuel supply mechanism), 20…Six-axis sensor, 21…Detection unit.

Claims

1. A hull, an engine mounted on the hull, a fuel supply mechanism for controlling the rotation of the engine, a steering device for steering, A personal watercraft comprising: a detection unit having a sensor for detecting at least one of the angular velocity and angular acceleration about the yaw axis of the hull, a control unit that performs deceleration control of the engine when the angular velocity or angular acceleration about the yaw axis detected by the detection unit exceeds a threshold value during turning of the hull, A personal watercraft characterized by comprising the above.

2. In the personal watercraft according to Claim 1, the control unit performs the first deceleration control based on the angular acceleration when the hull is turning in the same direction, and performs the deceleration control after the second time during turning in the same direction as the first time based on the angular velocity. A personal watercraft.

3. In the personal watercraft according to Claim 1, the detection unit has a six-axis sensor that detects the angular velocity and angular acceleration in the roll direction, the angular velocity and angular acceleration in the pitch direction, and the angular velocity and angular acceleration about the yaw axis, the control unit performs the deceleration control based on at least one of the angular velocity and angular acceleration about the yaw axis. A personal watercraft.

4. A control method for a personal watercraft comprising a hull, an engine, a fuel supply mechanism, and a steering device, detecting at least one of the angular velocity and angular acceleration about the yaw axis in a state where the hull is turning, performing deceleration control to decelerate the engine when the detected angular velocity or angular acceleration exceeds a threshold value. A control method for a personal watercraft.

5. In the control method for a personal watercraft according to Claim 4, detecting the angular velocity and angular acceleration about the yaw axis of the hull, performing the first deceleration control based on the angular acceleration when the hull is turning in the same direction, performing the deceleration control after the second time based on the angular velocity when the hull is turning in the same direction as the first time. A control method for a personal watercraft.

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