Outboard Motor Control for Rapid Turning via Reverse Thrust
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Solution Overview
Problem
Existing techniques for controlling outboard motors on a boat struggle to facilitate smooth rapid turning or repeated turning about a single point, particularly during trolling, as they do not effectively manage engine speed and rudder angle to achieve the desired maneuverability.
Innovation Solution
A control apparatus and method for outboard motors equipped with internal combustion engines and a transmission system, including an engine speed detector and rudder angle detector, which control the motors to operate the inner motor in reverse and the outer motor in forward first-speed gear when the engine speed is below a certain threshold and the rudder angle exceeds a predetermined value, allowing for precise control of turning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional control techniques are used to regulate outboard motor outputs in response to navigation conditions, then the boat can make turning smoothly under normal conditions, but it cannot make rapid turning or repeated turning about a same point smoothly
Solution Approach 1:
The control apparatus dynamically adjusts the operation mode of outboard motors based on real-time detection of engine speed and rudder angle. When rapid turning is detected (low engine speed + large rudder angle), the system switches the inner motor to reverse gear operation, creating dynamic adaptability that enables smooth rapid turning while maintaining normal operation characteristics under other conditions.
Solution Approach 2:
The system changes the operational parameters of the outboard motors by switching between different gear modes (forward vs. reverse) based on detected conditions. This parameter change allows the inner motor to generate thrust in opposite directions, enabling the boat to perform rapid turning and repeated turning about a same point smoothly.
2Force
If the inner motor operates in forward gear during turning, then the thrust direction is limited, but if operated in reverse gear, then the angular moment about the center of turning increases
Solution Approach 1:
The control apparatus applies the inversion principle by operating the inner motor in reverse gear during turning maneuvers. This causes the inner motor to generate thrust in the opposite direction compared to conventional operation, thereby increasing the angular moment about the center of turning and enabling more effective rapid turning.
3Power
If the engine speed is high, then the power transmission is efficient, but if the engine speed is low, then the gear shifting becomes difficult
Solution Approach 1:
The control apparatus performs preliminary action by detecting when engine speed drops to a predetermined level before gear shifting is attempted. When low engine speed is detected along with large rudder angle, the system proactively controls the inner motor to operate in reverse gear, preventing gear shifting difficulties from occurring in the first place.
Data Source
AI summary
In an apparatus for controlling operation of two outboard motors mounted on a stern of a boat side by side and each equipped with an internal combustion engine to power a propeller through a power transmission shaft and a transmission having a forward first-speed and a second-speed gear and a reverse gear supported on the power transmission shaft, control is conducted at turning of the boat to operate the inner one of the outboard motors to transmit the engine power to the propeller through the reverse gear, and to operate the outer one of the outboard motors to transmit the engine power to the propeller through the forward first-speed gear, when the detected engine speed is equal to or smaller than a predetermined first speed and the detected rudder angle is equal to or greater than a predetermined angle.