Marine Vessel Propulsion Trim Control for Reverse Thrust
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing marine vessel propulsion systems with multiple trimmable propulsion devices face limitations in reverse thrust capabilities, leading to inefficient maneuvers, especially during lateral movements, due to the overpowering of trim systems by reverse thrust forces, which results in reduced responsivity and thrust output.
Innovation Solution
The system determines individual reverse thrust limits for each propulsion device based on its specific trim system and moment arm, monitoring trim position changes to prevent 'trail out' and adjust engine RPM or torque accordingly, allowing for optimized thrust distribution across multiple propulsion devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If reverse thrust is increased to improve maneuvering capability, then lateral movement capability is improved, but the trim system is overpowered causing trail out and reduced control precision
Solution Approach 1:
The system continuously monitors trim position and provides feedback to the control system. When trail out is detected (trim position exceeds threshold), the control system automatically reduces engine RPM or torque to bring the trim position back within acceptable limits, enabling precise trim control even during high reverse thrust maneuvers
Solution Approach 2:
The system dynamically adjusts engine RPM or torque based on real-time trim position conditions. By making the thrust output variable rather than fixed, the system can maximize reverse thrust when needed while automatically reducing it when trim position indicates trail out, thus resolving the contradiction between maneuvering capability and control precision
2Reliability
If reverse thrust is limited to prevent trim system overload, then trim system reliability is improved, but thrust output and maneuvering efficiency are reduced
Solution Approach 1:
Rather than applying a static reverse thrust limit, the system dynamically adjusts thrust based on real-time trim position monitoring. This allows the system to maintain high thrust output when trim conditions are acceptable while automatically reducing thrust only when trail out begins, thus preserving both reliability and power
Solution Approach 2:
The system uses its own trim position sensors and control mechanisms to self-regulate reverse thrust output. The control system automatically detects trail out conditions and adjusts engine parameters without external intervention, enabling the system to protect itself while maintaining maximum performance
3Adaptability or versatility
If individual reverse thrust limits are determined for each propulsion device, then system adaptability is improved, but device complexity and control system complexity increase
Solution Approach 1:
The system divides the multi-propulsion vessel into individual propulsion device segments, each with its own trim position monitoring and reverse thrust limit determination. This segmentation allows each device to be optimized independently based on its specific moment arm and trim system characteristics, improving overall system adaptability
Solution Approach 2:
The control system uses a universal approach by determining reverse thrust limits based on common physical principles (moment arm calculations and trim position monitoring) that apply to all propulsion devices. This universal methodology, while accounting for individual device characteristics, avoids the need for completely separate control systems for each device, thus managing complexity
Data Source
AI summary
A method of controlling reverse thrust by a propulsion device on a marine vessel includes determining that the propulsion device is situated to effectuate a reverse thrust and determining an initial trim position of the propulsion device. An engine RPM or an engine torque of the propulsion device is then controlled to effectuate a reverse thrust, and a trim position of the propulsion device is monitored. If a threshold increase in trim position from the initial trim position is detected at an increased engine RPM or an increased engine torque, then a reverse thrust limit is calculated based on the increased engine RPM or increased engine torque. The engine RPM of the propulsion device is then controlled so as not to exceed the reverse thrust limit while the propulsion device is effectuating the reverse thrust.