Boat Shift Control Device Preventing Gearbox Damage at High Speed
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Solution Overview
Problem
Conventional shift-in prevention control schemes for boats with multiple engines fail to adequately protect engines and gearboxes when operating at high speeds, leading to increased load and potential gear breakdowns during shift-in operations.
Innovation Solution
A boat shift control device and method that utilize a rotational speed detector, LP sensor, and controller to detect simulated boat speed and prohibit shift-in when the speed exceeds a predetermined value, ensuring engines and gearboxes are protected by preventing shift-in operations during high-speed boat operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If shift-in is permitted during high-speed operation to maintain operational flexibility, then ease of operation is improved, but engine and gearbox reliability deteriorates due to increased load and potential gear breakdown
Solution Approach 1:
The control device applies preliminary anti-action by detecting simulated boat speed and proactively prohibiting shift-in operations before high-speed damage can occur. The controller monitors engine rotational speeds to calculate simulated boat speed, and when this exceeds a predetermined threshold, it automatically sets a shift-in prohibition flag to prevent gear engagement during unsafe conditions, thereby protecting the engine and gearbox from excessive load and potential breakdown
2Reliability
If shift-in prohibition is applied during high-speed operation to protect engines and gearboxes, then reliability is improved, but ease of operation deteriorates due to restricted shift-in control
Solution Approach 1:
The control device applies dynamics by making the shift-in prohibition status changeable based on real-time operating conditions. The controller continuously monitors simulated boat speed and dynamically adjusts the shift-in prohibition flag - prohibiting shift-in when simulated speed exceeds the threshold, but allowing it when speed drops below the threshold. This dynamic adjustment ensures protection during high-speed operation while maintaining operational flexibility when conditions are safe
Solution Approach 2:
The control device applies feedback by continuously monitoring engine rotational speeds via rotational speed detectors, calculating simulated boat speed, and using this information to automatically adjust shift-in control status. The system provides feedback to the operator through shift-in prohibition notifications, enabling informed operational decisions while maintaining engine and gearbox protection
3Ease of operation
If conventional shift-in prevention control is used based on simulated boat speed, then ease of operation is improved, but reliability deteriorates in multi-engine configurations where only one engine is in use
Solution Approach 1:
The control device applies universality by designing a multi-functional system that handles both single-engine and multi-engine configurations through the same control logic. The controller calculates simulated boat speed based on rotational speeds from multiple engines (detecting which engines are operating and which are in neutral), and applies shift-in prohibition based on this unified calculation. This universal approach ensures reliable protection whether one or multiple engines are in use, eliminating the need for separate control systems
Data Source
AI summary
Provided are an LP sensor that detects any one shift state from among forward, reverse and neutral, on the basis of an operation state of respective throttle levers corresponding to a plurality of engines, and a controller that controls the plurality of engines. The controller detects a simulated boat speed on the basis of the respective rotational speeds of the plurality of engines. When from a state in which the boat is operated by some engines from among the plurality of engines an attempt is made to operate the remaining engines being in a neutral shift state, the controller sets a shift-in prohibition flag of a corresponding engine, and prohibits shift-in control of the remaining engine, in a case where the simulated boat speed is higher than a first determination value.