Jet Watercraft Reverse Gate Deceleration Control
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Solution Overview
Problem
Existing methods for decelerating jet propelled watercraft result in noticeable sudden increases in deceleration, causing discomfort to the driver due to three distinct stages of deceleration as the reverse gate is lowered and thrust is applied.
Innovation Solution
A method involving a deceleration signal that moves the reverse gate to an intermediate position, increasing the thrust request and motor speed, thereby smoothing the deceleration process by reducing the thrust request before moving the reverse gate, and continuing to reduce motor speed as it approaches the deceleration position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the reverse gate is lowered and motor speed is increased to generate reverse thrust for deceleration, then the deceleration effectiveness is improved, but the driver experiences sudden noticeable increases in deceleration causing discomfort
Solution Approach 1:
The method applies preliminary action by reducing motor speed before lowering the reverse gate, and by progressively increasing thrust request as the gate approaches the deceleration position. This sequencing prepares the system in advance to smooth out the deceleration profile, preventing sudden changes that would cause driver discomfort while still achieving effective deceleration.
2Productivity
If the reverse gate is moved to the deceleration position, then the reverse thrust is generated to decelerate the watercraft, but the deceleration occurs in three distinct stages that are noticeable to the driver
Solution Approach 1:
The method applies dynamics by continuously adjusting the thrust request based on the reverse gate's position during movement. As the gate transitions from stowed to deceleration position, the thrust request is dynamically increased to compensate for the changing gate angle, creating a smooth and continuous deceleration force rather than distinct stages, thereby maintaining deceleration capability while improving smoothness.
3Object-affected harmful factors
If the motor speed is reduced before lowering the reverse gate, then the deceleration process is smoothed, but the overall deceleration time is extended
Solution Approach 1:
The method applies parameter changes by adjusting the thrust request as a variable parameter based on the reverse gate's position. As the gate moves toward the deceleration position, the thrust request is increased to optimize the balance between smoothness and time, allowing the system to maintain smooth deceleration while minimizing the overall deceleration time through dynamic parameter optimization.
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 approach reduces the suddenness of deceleration, providing a smoother and more comfortable deceleration experience for the driver by managing the reverse gate's position and motor speed in a controlled manner.
Implementation Method 1
jet propulsion system operatively connected to the motor
Implementation Method 2
lowering a reverse gate behind the output of the water jet thus redirecting the jet toward the front of the watercraft which creates a thrust in the reverse direction
Implementation Method 3
The first stage of deceleration occurs when the motor speed is first reduced and results from friction between the hull and water and from the resistance of the water to being displaced by the hull
Data Source
AI summary
A method of decelerating a watercraft is disclosed. The watercraft has a hull, a deck, a seat, a motor connected to at least one of the hull and the deck, a jet propulsion system operatively connected to the motor, and a reverse gate connected to at least one of the hull and the jet propulsion system. The reverse gate is movable between at least a stowed position and a deceleration position. The method has the steps of: receiving a deceleration signal; moving the reverse gate toward the deceleration position in response to receiving the deceleration signal; as the reverse gate is moving toward the deceleration position, increasing a thrust request at an intermediate position of the reverse gate, the intermediate position being intermediate the stowed and decelerations positions; and increasing the speed of the motor in response to increasing the thrust request.