Marine Propulsion Trim Control for Venting Prevention
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Solution Overview
Problem
Current auto-trim systems for marine vessels are insufficient in responding to prop venting or blowout events during high-speed turns, as they require a measured loss of speed before trimming down, leading to delayed responses and potential damage.
Innovation Solution
A system that automatically detects prop venting or blowout events by monitoring engine speed or load changes, and immediately adjusts the trim position of the propulsion device to a reduced position using a trim actuator controlled by a controller that receives engine speed and load data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current auto-trim systems wait for measured speed loss before trimming down, then the system maintains stability and avoids unnecessary trim adjustments, but the response to prop venting or blowout events is delayed
Solution Approach 1:
The system performs preliminary detection of prop venting or blowout conditions by monitoring engine parameters (RPM, load, throttle position) before actual speed loss occurs. When these preliminary indicators are detected, the controller proactively adjusts trim position to prevent the harmful event, rather than waiting for speed loss to confirm the problem.
Solution Approach 2:
The system continuously monitors engine parameters and provides feedback to the controller. When feedback indicates prop venting or blowout conditions (sudden RPM increase, load decrease, throttle position changes), the controller responds by adjusting trim position. This closed-loop feedback system enables timely detection and response without waiting for speed loss.
2Reliability
If the system immediately adjusts trim position upon detecting prop venting or blowout, then the duration and occurrence of these events is reduced, but the complexity of the control system increases
Solution Approach 1:
The control system monitors its own operating parameters (engine RPM, load, throttle position) and automatically detects prop venting or blowout conditions. The system serves itself by using readily available sensor data to trigger protective trim adjustments, eliminating the need for external detection devices or complex additional sensors.
Solution Approach 2:
The system detects prop venting or blowout by monitoring changes in engine parameters (RPM spike, load decrease, throttle position). When parameter changes indicate a harmful event, the controller changes the trim position parameter to correct the condition. This approach uses existing parameter monitoring capabilities rather than adding new detection systems.
3Device complexity
If the system uses existing engine parameters for detection, then the device complexity is minimized, but the precision of prop venting or blowout detection may be insufficient
Solution Approach 1:
The system merges multiple existing engine parameter measurements (RPM, load, throttle position) to detect prop venting or blowout events. By combining information from these different parameters, the system achieves more precise detection than any single parameter could provide alone, while using only sensors already present in the engine control system.
Solution Approach 2:
The existing engine control system and its sensors serve multiple functions: normal engine control, emission monitoring, and prop venting/blowout detection. The same RPM sensor, load sensor, and throttle position sensor used for routine engine operation are also used to detect harmful events, eliminating the need for dedicated detection hardware and maximizing the utility of existing components.
Data Source
AI summary
A method of controlling trim position of a propulsion device includes receiving a current engine speed and a current trim position of the propulsion device, and then detecting at least a threshold increase in engine speed of the propulsion device or at least a threshold drop in engine load on the propulsion device. A reduced trim position is then determined based on the current trim position, and a trim actuator is operated to move the propulsion device to the reduced trim position.