Watercraft Reverse Gate Control for High-Speed Deceleration
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Solution Overview
Problem
High-speed jet propelled watercraft experience unstable riding conditions when attempting to decelerate due to excessive reverse thrust, which can cause the stern to lift and the bow to dip, and the reverse gate may be pushed back by the high thrust, making it difficult to lower the gate effectively.
Innovation Solution
A method and system that utilize an electronic control unit (ECU) to control the thrust generated by the jet propulsion system independently of the throttle operator's position when the reverse gate is actuated at high speeds, by adjusting the engine's speed of rotation and the reverse gate's position, ensuring controlled deceleration without excessive thrust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the driver applies reverse thrust at high speeds to decelerate the watercraft, then the deceleration effect is improved, but the watercraft stability deteriorates due to stern lift and bow dip
Solution Approach 1:
The system dynamically adjusts the reverse thrust parameter based on watercraft speed. When speed exceeds a predetermined threshold, the ECU automatically limits the reverse thrust to a maximum level that prevents stern lift and bow dip, while still providing effective deceleration. This parameter change resolves the contradiction by adapting the thrust level to the operating conditions.
2Speed
If the driver attempts to lower the reverse gate at high speeds, then the deceleration capability is improved, but the reverse gate operation fails as the gate is pushed back by high thrust
Solution Approach 1:
The ECU performs preliminary action by detecting when the reverse gate operator is actuated and the watercraft speed is above the threshold, then proactively reducing the thrust to a level that allows the reverse gate to be lowered successfully. This preliminary thrust reduction prevents the gate from being pushed back, enabling successful gate operation at high speeds.
Solution Approach 2:
The system uses feedback from the reverse gate operator position and watercraft speed sensors to continuously monitor operating conditions. When the gate operator is actuated at high speed, the ECU receives this feedback and automatically adjusts the thrust accordingly, creating a closed-loop control system that ensures successful gate operation.
3Ease of operation
If the driver controls reverse thrust independently at high speeds, then the deceleration control is improved, but the system complexity increases due to independent ECU control
Solution Approach 1:
The ECU serves multiple functions: it controls normal throttle operation, monitors watercraft speed, detects reverse gate operator actuation, and independently controls reverse thrust when needed. By making the ECU multi-functional, the patent avoids adding separate dedicated hardware for high-speed reverse control, thus managing complexity while providing improved deceleration control.
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
This solution allows for controlled deceleration of the watercraft at high speeds, preventing unstable riding conditions and ensuring the reverse gate can be effectively lowered, maintaining stability and control during deceleration.
Implementation Method 1
a jet propulsion system connected to the hull and operatively connected to the engine
Implementation Method 2
the reverse gate redirects a jet of water expelled from the jet propulsion system
Data Source
AI summary
A method of controlling a watercraft is disclosed which comprises actuating a reverse gate operator, sensing a speed of the watercraft, controlling a thrust generated by a jet propulsion system differently depending on whether the speed of the watercraft is above or below a predetermine watercraft speed when the reverse gate operator is actuated, and moving the reverse gate to a position in which the reverse gate redirects a jet of water expelled from the jet propulsion system in response to the actuation of the reverse gate operator. A watercraft implementing the above method is also disclosed.