Engine output control for watercraft

Abstract

A watercraft includes an improved engine control system that enhances the responsiveness of the watercraft and eases watercraft operation. The watercraft includes a propulsion device, such as a jet propulsion unit, and an engine that powers the propulsion device. The engine control system is configured to maintain or increase engine speed under certain operating conditions.

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         33 . A watercraft comprising a water propulsion device, an engine powering the water propulsion device, the engine having at least one combustion chamber and an air induction system arranged to provide air to the combustion chamber, at least one throttle valve disposed in the air induction system for regulating an amount of air supplied to the combustion chamber, a steering assembly arranged to steer the watercraft, a first sensor arranged to sense an opening degree of the throttle valve, a second sensor arranged to sense an angular position of the steering assembly, an electrically operated control device, and a throttle valve actuator arranged to operate the opening degree of the throttle valve, the control device being configured to control the throttle valve actuator based upon an output of the first sensor and an output of the second sensor, the control device causing the throttle valve actuator to operate the at least one throttle valve to increase its opening degree when the output of the first sensor indicates that the sensed opening degree less than a reference opening degree and the output of the second sensor indicates that the sensed angular position is greater than a reference angular position.  
     
     
         34 . The watercraft as set forth in  claim 33  additionally comprising a third sensor arranged to sense a velocity of the watercraft, wherein the control device coerces the throttle valve actuator into operating the throttle valve to increase the opening degree unless an output of the third sensor indicates that the velocity of the watercraft is less than a reference velocity.  
     
     
         35 . The watercraft as set forth in  claim 34 , wherein the control device includes a storage to store data of opening degrees of the throttle valve versus velocities of the watercraft, the control device determines one of the opening degrees that corresponds to the sensed output of the third sensor as an objective opening degree, and the control device controls the throttle valve actuator to operate the throttle valve to increase the opening degree to the objective opening degree.  
     
     
         36 . The watercraft as set forth in  claim 35 , wherein the control device ceases the coercion control when the sensed opening degree of the throttle valve increases to the objective opening degree, the sensed angular position of the steering assembly is generally zero, or the sensed velocity of the watercraft is less than a second reference velocity.  
     
     
         37 . The watercraft as set forth in  claim 35 , wherein the control device includes a timer, and the control device ceases the coercion control when a predetermined time elapses.  
     
     
         38 . The watercraft as set forth in  claim 34 , wherein the control device includes a storage to store data of opening degrees of the throttle valve versus velocities of the watercraft and data of the angular positions of the steering assembly versus velocities of the watercraft, the control device determines one of the opening degrees that corresponds to the sensed output of the third sensor as the reference opening degree and also determines one of the angular positions that corresponds to the sensed output of the third sensor as the reference angular position.  
     
     
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         42 . A control method for an engine of a watercraft having a water propulsion device, a steering assembly, at least two sensors and a control device, the engine including a throttle valve and a throttle valve actuator, the method comprising sensing an opening degree of the throttle valve by one sensor, sensing an angular position of the steering assembly by another sensor, determining whether the sensed opening degree is less than a reference opening degree, determining whether the sensed angular position is greater than a reference angular position, and increasing the opening degree by the control device if the results of both determinations are affirmative.  
     
     
         43 . The control method as set forth in  claim 42  additionally comprising sensing a velocity of the watercraft, determining whether the sensed velocity is greater than a reference velocity, and increasing the opening degree unless a result of the determination of the velocity is negative.  
     
     
         44 . The control method as set forth in  claim 43  additionally comprising storing data of opening degrees of the throttle valve versus velocities of the watercraft in a storage of the control device, determining one of the opening degrees that corresponds to the sensed velocity as an objective opening degree, and increasing the opening degree by the throttle valve actuator to the objective opening degree.  
     
     
         45 . The control method as set forth in  claim 44  additionally comprising judging whether the sensed opening degree increases beyond the objective opening degree, judging whether the sensed angular position is generally zero, judging whether the sensed velocity is less than a second reference velocity, and ceasing the increase of the opening degree if at least one of results of the judgments is affirmative.  
     
     
         46 . The control method as set forth in  claim 45  additionally comprising storing data of opening degrees of the throttle valve versus velocities of the watercraft in a storage of the control device, storing data of the angular positions of the steering assembly versus velocities of the watercraft in the storage of the control device, determining one of the opening degrees that corresponds to the sensed velocity as the reference opening degree, and determining one of the angular positions that corresponds to the sensed velocity as the reference angular position.