JP4619515B2 - Jet-propelled planing boat - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a jet-propelled planing boat such as a small planing boat (Personal Watercraft (also called PWC)) that jets a water flow backward and navigates the water by its reaction, and in particular, the throttle is turned off. Sometimes it relates to a jet-propelled planing boat that can maintain the steering function.
[0002]
[Background Art and Problems to be Solved by the Invention]
In recent years, so-called jet-propelled planing boats have been widely used for leisure, sports or rescue. In this jet propulsion type personal watercraft, generally, water sucked from a water inlet provided on the bottom of the boat is pressurized and accelerated by a water jet pump and propelled backwards to propel the hull.
[0003]
And, in the case of this jet propulsion type personal watercraft, by changing the water injection direction to the left and right by swinging the steering nozzle arranged behind the water jet pump injection port to the left and right, Steer the boat to the right or left.
[0004]
Therefore, in the case of a jet-propelled planing boat having such a configuration, when the throttle is closed to a fully closed position and the amount of water injected from the water jet pump is reduced, the thrust that can be used to turn the boat (for steering) At the same time, the ability to steer the boat is reduced until the throttle is reopened.
[0005]
In view of such a current situation, the present applicant has confirmed that the steering for steering that can maintain the ability to steer mechanically even if the throttle is closed to near full close and the amount of water injection from the water jet pump decreases. A jet propulsion type personal watercraft provided with a member was provided (Japanese Patent Application No. 2000-6708).
[0006]
Further, in the case of the jet propulsion type personal watercraft, the number of parts increases, the structure becomes complicated, and the weight increases. In addition, jet propulsion planing boats configured to maintain the steering function by increasing the engine speed to maintain the water injection amount were provided (Japanese Patent Application Nos. 2000-6708, 142664, 14242639).
[0007]
An object of the present invention is to provide a jet propulsion personal watercraft that can be steered according to the steering angle in the jet propulsion personal watercraft.
[0008]
[Means for Solving the Problems]
The present invention can solve the above problems by a jet propulsion type personal watercraft having the following configuration. That is,
The jet propulsion type personal watercraft according to the present invention sprays water pressurized and accelerated by a water jet pump from the rear injection port and propels it by reaction, and when the throttle is turned off and the steering wheel is steered, A jet-propelled planing boat configured to detect the steering by a steering position detection sensor and temporarily increase the engine speed to increase the water injection amount from the injection port to maintain the steering function. In
The steering position detection sensor is provided,
According to the steering position detected by the steering position detection sensor, the cumulative water injection amount while changing the engine speed is changed.
It is characterized by that.
[0009]
Thus, according to the jet propulsion type personal watercraft configured as described above, the jet propelled watercraft is injected within a predetermined time (time during which the engine speed is increased) from the injection port of the water jet pump according to the steering angle. Since the control is performed by changing the amount of water, that is, the “cumulative water injection amount”, for example, when the rider wants to turn with a small turning radius, a large water injection amount can be obtained by steering with a large steering angle. If the rider wants to turn with a large turning radius, the small water injection amount can be obtained by steering with a small steering angle, and a large turning radius can be obtained. It will be possible to turn in.
[0010]
In this specification, when a signal indicating that the throttle is turned off is obtained from the throttle opening detection sensor or the like and a signal that the steering is operated is obtained from the steering position detection sensor, the engine temporarily Control that increases the number of revolutions and maintains the steering function is called “off-throttle / steering mode control”. Further, in this specification, the “OFF operation” of the throttle means an operation in which the throttle is operated to a “closed” side by a predetermined amount or more.
[0011]
In the jet propulsion type personal watercraft, if the steering position detection sensor is configured to detect two or more steering positions in steering to the right or left, a detection system having a relatively simple configuration is provided. It can be realized.
[0012]
In the jet propulsion type personal watercraft, when the steering position detection sensor is configured by a potentiometer, it is easy to have a larger number of detection positions within the steering range, and therefore control with higher resolution is possible. Can be realized.
[0013]
In the jet propulsion type personal watercraft, when the steering position detection sensor is configured to detect the steering position at each position obtained by dividing the one-side maximum steering angle to the right side or the left side into three equal parts, it is relatively simple. Thus, it is possible to perform control with a resolution that can be practically sufficient while maintaining a simple configuration.
[0014]
Further, in the jet propulsion type personal watercraft, the cumulative water injection amount may be changed by changing the time during which the engine speed is increased, or by changing the increase range of the engine speed. It may be implemented or both may be implemented simultaneously by changing them.
[0015]
Further, in the jet propulsion type personal watercraft, when the change in the engine speed increase is performed according to the steering speed obtained from the detection position of the steering position detection sensor, for example, the rider has a small turning radius and is compared. If the vehicle wants to turn at a high speed, a large water injection amount can be obtained when steering with a large steering angle, and if the rider wants a relatively low-speed turn with a large turning radius, a small steering angle is obtained. When the steering is performed, a small water injection amount can be obtained. Further, since the steering speed is used as input information for this control instead of the steering angle, it is possible to perform control independent of the magnitude of the steering angle.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a jet propulsion personal watercraft according to an embodiment of the present invention will be specifically described with reference to the drawings, taking a small personal watercraft as an example.
[0017]
(First embodiment)
FIG. 1 is a block diagram showing a control-related configuration of a jet propulsion personal watercraft according to an embodiment of the present invention, FIG. 2 is a flowchart showing control contents of components shown in the block diagram of FIG. 1, and FIG. FIG. 4 is a plan view of FIG. 3, FIG. 5 is a partially enlarged sectional view of the vicinity of the steering in FIG. 3, FIG. 6 is an exploded perspective view of the main part of the steering portion, and FIG. FIG. 3 is a diagram showing the configuration shown in the block diagram of FIG. 2 in relation to an actual engine.
[0018]
3 and 4, A is a hull, and this hull A is composed of a hull H and a deck D covering the hull H, and a connection line connecting the hull H and the deck D all around is called a gunnel line G. In this embodiment, the gunnel line G is located above the waterline L of the personal watercraft.
[0019]
As shown in FIG. 4, a substantially rectangular opening 16 is formed in the upper surface of the hull A in a plan view extending in the longitudinal direction slightly behind the center of the deck D, and is illustrated in FIGS. Thus, a seat S for riding is disposed above the opening 16.
[0020]
The engine E is disposed in a space 20 having a “convex” cross section surrounded by the hull H and the deck D below the seat S.
[0021]
This engine E is a multi-cylinder engine (three cylinders in this embodiment), and is mounted with the crankshaft 10b oriented in the longitudinal direction of the hull A as shown in FIG. The output end of the shaft 10b is connected to the pump shaft side of the water jet pump P to which the impeller 21 is attached via the propeller shaft 15 so as to be integrally rotatable. The outer periphery of the impeller 21 is covered with a pump casing 21C. Water taken from a water supply port 17 provided on the bottom surface of the personal watercraft is taken in via a water absorption passage and is added by a water jet pump P. It is configured to obtain a propulsive force through pressure / acceleration and discharge from the rear end injection port 21K through a pump nozzle (spout part) 21R whose water flow cross-sectional area becomes smaller as it goes backward.
[0022]
In FIG. 3, 21V is a stationary blade for rectification. 3 and 4, reference numeral 10 denotes a steering handle as a steering operation means. By operating the handle 10 left and right, the steering nozzle 18 behind the pump nozzle 21R is swung left and right. When the water jet pump P is in operation, the boat can be steered in a desired direction.
[0023]
As shown in FIG. 3, a bowl-shaped reverse deflector 19 (FIG. 3) is provided above and below the steering nozzle 18 so as to be able to swing downward about a horizontally disposed swing shaft 19a. Reference) is arranged, and by swinging the deflector 19 to a lower position behind the steering nozzle 18, the water discharged backward from the steering nozzle 18 is turned forward to be moved backward.
[0024]
3 and 4, reference numeral 12 denotes a rear deck. The rear deck 12 is provided with an openable / closable hatch cover 29, and a small-capacity storage box is formed below the hatch cover 29. 3 or 4, reference numeral 23 denotes a front hatch cover, and a box (not shown) for storing equipment and the like is provided below the hatch cover 23. Further, another hatch cover 25 is disposed above the front hatch cover 23 to form a two-layer hatch cover, and the hatch cover 25 has an opening (not shown) provided on the rear end face. The life jacket etc. can be stored in the inside.
[0025]
By the way, in the personal watercraft according to the embodiment of the present invention, as shown in FIGS. 5 and 6, in the vicinity of the rotary shaft 10A of the handle 10, the steering is constituted by the proximity switch on the rotating side and the fixed side. A position detection sensor Sp is arranged. In this embodiment, the steering position detection sensor Sp is a sensor which is disposed when the permanent magnet 40 is disposed at one position of the disk-shaped member on the rotation side and at four positions on the fixed side when the permanent magnet 40 approaches. .. Are formed by arranging 41, 41,...
[0026]
In this embodiment, as shown in FIG. 6, the rotation-side permanent magnet 40 is arranged at a rotation direction position corresponding to the neutral position of the handle 10, and the fixed-side permanent magnets 41, 41,. Two locations are arranged at right angles and left steering directions at predetermined angular positions so as to be subject to left and right. In the present embodiment, two detection positions are provided for steering in the respective directions to the right or left. However, in the present invention, a configuration in which three or more detection positions are provided is also possible. It is.
[0027]
Further, as shown in FIG. 7, a throttle opening degree detection sensor Sb is disposed in the vicinity of the butterfly valve 51 disposed in the intake passage 3 of the engine E. Further, as shown in FIG. 7, an engine speed detection sensor Se is disposed in the vicinity of the crankshaft Cr.
[0028]
As shown in FIG. 1, the steering position detection sensor Sp, the throttle opening degree detection sensor Sb, and the engine speed detection sensor Se are each connected to the engine control unit Ec by signal lines (electric wires). The signals detected by these sensors are transmitted to the engine control unit Ec.
[0029]
The engine control unit Ec is connected to a fuel injection device Fe disposed in the cylinder head Hc of the engine E by a signal line (electric wire). The engine control unit Ec is connected to the ignition coil Ic by a signal line (electric wire).
[0030]
The ignition coil Ic is connected to the ignition plug Ip by an electric wire (high voltage electric cord). In FIG. 7, 4 indicates a fuel tank, and 5 indicates a fuel booster pump.
[0031]
Thus, the jet propulsion personal watercraft according to the embodiment of the present invention configured as described above performs the off-throttle / steering mode control and maintains the steering function when the throttle is turned off as follows. can do. The control contents of the control program recorded in the memory of the computer built in the engine control unit Ec will be described below with reference to the flowchart of FIG.
[0032]
In other words, when the small planing boat, which is a jet propulsion planing boat, is sliding, when the rider turns off the throttle of the small planing boat, the throttle opening detection sensor Sb is turned off (results from the OFF operation). 8 is detected (see step 1 (S1)), and the signal is transmitted to the engine control unit Ec.
[0033]
In such a state, when the rider operates the handle 10 to the right or left by a predetermined angle and the permanent magnet 40 approaches the sensor 41 on this side, the sensor 41 is turned on and the steering position detection is performed. The sensor Sp detects the ON signal (step 2 (S2)) and transmits the signal to the engine control unit Ec.
[0034]
Then, the engine speed detection sensor Se detects the engine speed at that time (step 3 (S3)).
[0035]
Next, the engine control unit Ec checks whether or not the detected engine speed is equal to or lower than a predetermined speed, for example, 5500 rpm or lower (step 4 (S4)).
[0036]
Then, when the engine speed is less than a predetermined speed, for example, 5500 rpm or less, the off-throttle / steering mode control is started, and as it is, the engine E trying to descend to the idling state in a very short time The rotation speed is temporarily increased to a predetermined rotation speed (for example, 3000 rpm) on the increase line Za for a predetermined time (step 5 (S5)). That is, even when the engine speed is 5500 rpm on the descending line Zb in FIG. 8, the output is very low, and therefore the water jet pump P cannot be driven, that is, the state where the “engine brake” is activated. In order to drive the water jet pump P by the off-throttle / steering mode control, the rotational speed of the engine E at the increase line Za in FIG. Increase to a few, for example 3000 rpm. In FIG. 8, a broken line U represents the thrust of the water jet pump P at that time, and the difference h in the vertical axis direction between this line U and the increase line Za or the descending line Zb is accelerated or This represents the magnitude of PS (horsepower) that causes deceleration. Therefore, in order to start the off-throttle / steering mode control in the state indicated by 5500 rpm of the descending line Zb and to obtain the state indicated by 3000 rpm of the increasing line Za, the engine is substantially changed by changing the fuel injection timing or the like. An operation for increasing the rotation speed of E is required. In FIG. 8, the arrows of the increase line Za and the descending line Zb indicate the direction of change in the engine speed.
[0037]
In step 5 described above, the predetermined time, that is, the time during which the engine speed is increased (herein referred to as “rising period”), and the degree to which the engine speed is increased to the predetermined speed (increase range), Is set based on a signal transmitted from the steering position detection sensor Sp to the engine control unit Ec, that is, a steering angle. The identification of the steering angle by the engine control unit Ec can be realized, for example, by varying the signal voltage (or pulse width or the like when using PWM control) output from each sensor 41 of the steering position detection sensor Sp. . Further, even if the signal voltage output from each sensor 41 is the same, for example, it can be specified by inputting a signal from each of the different input terminals to the engine control unit Ec with different signal lines (electric wires). It is. Further, even when the signal voltage output from each sensor 41 is the same as described above, the detection history is stored in the built-in memory of the engine control unit Ec and specified based on this detection history. It is also possible. However, in this case, for example, another sensor that detects the neutral position of the steering wheel 10 is provided, and a device that resets the engine at start-up and identifies right steering or left steering is performed by a signal from the sensor. Is required.
[0038]
Next, the fuel injection timing and / or ignition timing is returned to the original state (normal operation state) (step 6 (S6)), and the off-throttle / steering mode control is terminated. At this time, as a condition for returning to the original state, for example, when the steering period detection sensor Sp detects that the ascending period set in step 5 has elapsed, or that the rider has returned the operation of the steering wheel 10, Try to bring it back.
[0039]
By performing the above-described series of off-throttle / steering mode control, the steering function is maintained even when the throttle is turned off.
[0040]
According to the jet propulsion personal watercraft configured as described above, the throttle opening detection sensor Sb and the engine speed detection sensor Se are also provided in a conventional jet propulsion personal watercraft. Since the engine control unit Ec is also provided, this can be realized by newly providing only the steering position detection sensor Sp consisting of a proximity switch and changing only the control program of the engine control unit Ec.
[0041]
Further, the “off-throttle / steering mode control” for temporarily increasing the engine speed may be configured not to be executed when the engine is in an idling region (for example, 800 to 2000 rpm). This configuration is a preferred embodiment in that the engine speed does not rise from the idling region when no extra driving force is required.
[0042]
(Second Embodiment)
As another embodiment of the steering angle detection system, as shown in FIG. 9, it is also possible to arrange a steering position detection sensor Sp composed of a potentiometer on the rotating shaft 10A portion of the handle 10.
[0043]
More specifically, the steering position detection sensor Sp detects a relative rotation angle of the rotating shaft 10A corresponding to the steering angle indicating the direction and magnitude of steering to the right or left side with the hull A as a fixed side, A voltage corresponding to the detected angle is output.
[0044]
Therefore, the engine control unit Ec performs the off-throttle / steering mode control by setting the rising period and the rising width based on the signal voltage transmitted from the steering position detection sensor Sp as in the first embodiment.
[0045]
Note that the potentiometer can basically detect the steering angle as described above continuously in an angular manner, but in the present invention, a very large number of detection positions are provided according to the detection resolution. It is what has.
[0046]
(Third embodiment)
Further, as yet another embodiment of the steering angle detection system, as shown in FIG. 10, an annular disk 30 having a protrusion 30p on a part of its outer peripheral surface in the middle of the rotational axis 10A of the handle 10 in the longitudinal direction. Fit outside. In this embodiment, the protrusion 30p has the handle 10 in the neutral position P. _N In such a state, it is arranged so as to face the front front, and rotates together with the rotation shaft 10A according to the rotation operation of the handle 10.
[0047]
Handle stoppers 32R and 32L are arranged at appropriate positions on both the left and right sides of the operating range of the protrusion 30p according to such steering operation, respectively, That is, one side maximum steering angle P _R , P _L Is regulated. In this embodiment, the one-side maximum steering angle P _R , P _L Is about 20 degrees. However, the arrangement position of the protrusion 30p of the annular disc 30 and the handle stoppers 32R and 32L corresponding thereto is not limited to that described above, but the handle 10 can be steered at an equal angle in the left-right direction. In addition, it is preferable to determine the positional relationship between the two.
[0048]
Further, a steering position detection sensor Sp constituted by a proximity switch is disposed on the rotating side and the fixed side in the vicinity of the tip of the protruding portion 30p of the annular disc 30. In this embodiment, the steering position detection sensor Sp includes sensors 41 and 41 that are turned on when the permanent magnets 40 come close to the fixed side, and the permanent magnets 40 are disposed on the fixed side. ,... Are arranged.
[0049]
In this embodiment, as shown in FIG. 10, the permanent magnets 41, 41,... On the fixed side have their one-side maximum steering angles P in the right steering direction or the left steering direction. _R , P _L And the angular position and neutral position P _N Are equally distributed at two angular positions obtained by dividing the angle between the two into three equal parts. Instead of such an arrangement, the permanent magnets 41, 41,... Can be equally arranged at any angular position within the above-mentioned three-divided angle range.
[0050]
The steering angle detection system of the present embodiment is configured as described above. As in the first embodiment, the output signal of each sensor 41 is identified, and the steering angle corresponding to the position where each sensor 41 is disposed is determined. The engine control unit Ec is configured to perform the off-throttle / steering mode control by setting the above-described ascending period and ascending range according to the identified steering angle.
[0051]
(Fourth embodiment)
Moreover, in the jet propulsion type personal watercraft according to the first embodiment, the water injection amount from the water jet pump P is temporarily increased or decreased according to the magnitude of the steering angle. As described above, it is also possible to obtain the steering speed (also referred to as the steering angular speed) based on the steering angle detected by the steering position detection sensor Sp, and to perform the off-throttle / steering mode control based on the steering speed. However, since this embodiment is the same as the first embodiment in terms of its substantial hardware configuration, the contents of the operation and the memory of the computer built in the engine control unit Ec will be described below. Only the control contents of the control program recorded in the above will be described with reference to the flowchart of FIG.
[0052]
In other words, when the small planing boat, which is a jet propulsion planing boat, is sliding, when the rider turns off the throttle of the small planing boat, the throttle opening detection sensor Sb is turned off (results from the OFF operation). 8 is detected (see step 1a (S1a)), and the signal is transmitted to the engine control unit Ec.
[0053]
In such a state, when the rider operates the handle 10 to the right or left by a predetermined angle and the permanent magnet 40 approaches the sensor 41 on this side, the sensor 41 is turned on and the steering position detection is performed. The sensor Sp detects the ON signal (step 2a (S2a)) and transmits the signal to the engine control unit Ec.
[0054]
At this time, there are a case where one sensor 41 on the same side is turned ON within a predetermined time and a case where the two sensors 41 and 41 are turned ON sequentially, and the number of these sensors 41 which are turned ON. Accordingly, the engine control unit Ec calculates the steering speed (step 3a (S3a)). This calculation can be easily realized, for example, by storing a correspondence table of steering angles corresponding to the number of sensors 41 that are turned on in the built-in memory of the engine control unit Ec.
[0055]
Subsequently, the engine speed detection sensor Se detects the engine speed at that time (step 4a (S4a)).
[0056]
Next, the engine control unit Ec checks whether or not the detected engine speed is equal to or lower than a predetermined speed, for example, 5500 rpm or less (step 5a (S5a)).
[0057]
Then, when the engine speed is less than a predetermined speed, for example, 5500 rpm or less, the off-throttle / steering mode control is started, and as it is, the engine E is about to descend to the idling state in a very short time. The rotation speed is temporarily increased to a predetermined rotation speed (for example, 3000 rpm) on the increase line Za for a predetermined time (step 6a (S6a)).
[0058]
Further, in step 6a, the predetermined time, that is, the time during which the engine speed is increased (herein, referred to as “rising period”) and the extent to which the engine speed is increased to the predetermined speed (increase range) are: It is set based on the steering speed obtained in step 3a.
[0059]
Then, the fuel injection timing and / or the ignition timing are returned to the original state (normal operation state) (step 7a (S7a)), and the off-throttle / steering mode control is terminated. At this time, as a condition for returning to the original state, for example, when the ascending period set in Step 6a has elapsed, or when the steering position detection sensor Sp detects that the rider has returned the operation of the steering wheel 10, Try to bring it back.
[0060]
By performing the series of off-throttle / steering mode control, the steering function is maintained according to the steering speed even when the throttle is turned off. Needless to say, the control according to the steering speed as in the present embodiment can also be realized by using the steering angle detection system shown in the second and third embodiments.
[0061]
In the above four embodiments, the steering position detection sensor Sp is configured as a rotation type detection system that directly detects the rotation of the rotation shaft 10A of the handle 10. However, the present invention is not limited to this. 10A is connected to a wire via the protrusion 30p of the annular plate 30 as described above, and a proximity sensor (a linear potentiometer can be substituted) is used as a linear arrangement with this wire as the movable side. By doing so, a linear detection system may be configured.
[0062]
Further, in the above four embodiments, the forward or backward movement is not particularly limited, but the present invention can be applied to either case.
[0063]
【The invention's effect】
According to the present invention, the apparatus already equipped in the past is utilized to the maximum, the throttle opening is in the idling region with a simple configuration and without increasing the weight, and the water from the water jet pump. Even when the injection amount decreases, it is possible to provide a jet propulsion type personal watercraft that can obtain an injection amount corresponding to the magnitude of steering and maintain the steering of the boat.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a control-related configuration of a jet propulsion personal watercraft according to an embodiment of the present invention.
FIG. 2 is a flowchart showing control contents of components shown in the block diagram of FIG. 1;
FIG. 3 is an overall side view of a personal watercraft according to an embodiment of the present invention.
4 is an overall plan view of the personal watercraft shown in FIG. 3. FIG.
5 is a partially enlarged cross-sectional view in the vicinity of the steering shown in FIG. 3, showing the arrangement position and configuration of the steering position detection sensor.
6 is an exploded perspective view of a main part of a steering portion showing the arrangement position of the steering position detection sensor shown in FIG. 5 and the configuration in the vicinity thereof. FIG.
FIG. 7 is a diagram showing the configuration of the control relationship shown in FIG. 1 in relation to an actual engine.
FIG. 8 shows PS (horsepower) or load on the vertical axis and engine speed (k is “1000”) on the horizontal axis, and the relationship between the increase and decrease of engine speed and horsepower; It is a figure showing the state of thrust of a water jet pump.
FIG. 9 is an exploded perspective view of a main part of a steering portion, showing the arrangement of a steering position detection sensor and the configuration of another embodiment in the vicinity thereof.
FIG. 10 is a schematic plan view of a main part of a steering portion, showing the arrangement of a steering position detection sensor and the configuration of another embodiment in the vicinity thereof.
FIG. 11 is a flowchart showing the control content of another embodiment of the components shown in the block diagram of FIG. 1;
[Explanation of symbols]
P …… Water jet pump
21K …… Injection port
E …… Engine
Sp: Steering position detection sensor
Sb …… Throttle opening detection sensor

Claims (7)

In a jet-propelled planing boat that injects water pressurized and accelerated by a water jet pump from the rear injection port and propels it by reaction ,
A steering position detection sensor for detecting that the steering wheel is steered from the neutral position to the left side or the right side;
And a engine control unit to increase the water injection amount from the injection opening by temporarily increasing the engine speed when the steering of the throttle OFF operation and the handle is performed,
The steering position detection sensor is configured to be able to detect two or more steering positions between the neutral position and the one-side maximum steering angle to the right or left side,
The engine control unit is configured so that when the throttle is turned off and the steering wheel is steered, the engine control unit is connected to the injection port while increasing the engine speed according to the steering position detected by the steering position detection sensor . A jet propulsion personal watercraft configured to change a cumulative water injection amount.   The jet propulsion personal watercraft according to claim 1, wherein the steering position detection sensor includes a potentiometer.   2. The jet propulsion personal watercraft according to claim 1, wherein the steering position detection sensor is configured to detect a steering position at each position obtained by dividing a maximum steering angle on one side to the right or left into three equal parts. . The jet propulsion personal watercraft according to any one of claims 1 to 3 , wherein the cumulative water injection amount is changed by changing a time during which the engine speed is increased. The jet propulsion planing boat according to any one of claims 1 to 3 , wherein the cumulative water injection amount is changed by changing a range of increase in engine speed. The change in the accumulated water injection amount, and changing the length of time that increases the engine speed, according to claim 1 to 3, characterized in that performed by both the changing the rise of the engine speed The jet propulsion planing boat described in any one of the items. The calculated steering speed based on the steering position detection sensor of the detection results, to any one of claims 1-3, characterized in that to change the rise of the engine speed according to the steering speed The jet propulsion planing boat described.

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