Marine Jet Propulsion Reverse Gate for Low-Speed Maneuvering
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Solution Overview
Problem
Conventional marine vessel propulsion systems with jet propulsion units face difficulties in maneuvering at low speeds due to large hull inertia, requiring complex operations involving throttle, reverse gate positioning, and steering, and existing solutions like skegs or rudders compromise high-speed efficiency or convenience.
Innovation Solution
A marine vessel propulsion device with a reverse gate that can be positioned at a second partially closed position to balance forward and reverse propulsive forces, allowing for improved steering response without sacrificing high-speed performance or convenience, by integrating a lever system that automatically adjusts throttle and gate openings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the reverse gate is positioned at a partially closed position between neutral and fully closed to enable low-speed movement, then the hull can be moved at low speed, but the hull cannot be driven forward because the reverse direction propulsive force surpasses the forward direction propulsive force
Solution Approach 1:
The patent introduces a lever with multiple discrete positions (gate fully opened position, forward drive starting position, neutral position, reverse drive starting position, maximum output reverse drive position) that dynamically adjusts the reverse gate opening degree and throttle opening degree in coordination. This dynamic positioning system allows the operator to select appropriate configurations for different operational needs, resolving the contradiction between low-speed movement capability and forward driving capability by providing optimized settings for each mode.
Solution Approach 2:
The patent changes the parameters of throttle opening degree and gate opening degree in specific combinations corresponding to different lever positions. At the forward drive starting position, the system sets a specific throttle opening degree and a specific gate opening degree that allows partial closing of the gate while maintaining sufficient forward propulsive force, thereby enabling both low-speed movement and forward driving capability simultaneously.
2Ease of operation
If the operator operates the right lever and left lever simultaneously along with the steering assembly to steer the hull at low speed, then steering is achieved, but the operation becomes complicated
Solution Approach 1:
The patent merges the functions of throttle control, reverse gate control, and steering control into a single integrated lever system. The lever simultaneously controls both the throttle opening degree and the reverse gate opening degree through mechanical linkages, reducing the number of independent controls the operator must manage and simplifying the overall operation while maintaining full steering capability.
Solution Approach 2:
The single lever performs multiple functions: it controls the throttle valve opening degree, controls the reverse gate opening degree, and works in conjunction with the steering assembly. This multi-functional design eliminates the need for separate controls for each function, reducing operational complexity while maintaining comprehensive control capabilities.
3Ease of operation
If a skeg or rudder is added to improve low-speed maneuvering, then steering response is improved, but high-speed efficiency or convenience is compromised
Solution Approach 1:
The patent replaces the need for mechanical additions like skegs or rudders with a controlled fluid dynamic system. By precisely controlling the reverse gate opening degree and throttle opening degree in coordination, the system achieves improved low-speed maneuvering response through optimized propulsive force distribution, eliminating the need for additional mechanical steering surfaces that would compromise high-speed efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables excellent maneuvering performance during low-speed travel by canceling inertial turning and simplifying operations, without the need for additional structures like skegs or rudders, thus maintaining high-speed efficiency and ease of boarding/exiting.
Implementation Method 1
a jet propulsion unit that jets water to generate a propulsive force
Implementation Method 2
the reverse gate covers an entirety of an opening of the thrust guide and reverses the water, jetted from the nozzle and through the thrust guide, to a forward direction
Data Source
AI summary
A marine vessel propulsion device includes an engine, a jet propulsion unit, and a reverse gate. The jet propulsion unit includes a jet port arranged to jet water toward a rear of a hull. The reverse gate is arranged to be capable of being changed in opening degree between a fully closed position of covering an entirety of the jet port and a fully opened position of not covering the jet port at all. The reverse gate is arranged to be moved, between the fully closed position and the fully opened position, to a first partially closed position of only partially covering the jet port and a second partially closed position of only partially covering the jet port and being closer to the fully opened position than the first partially closed position.