Propulsion Unit Speed Synchronization Control
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Solution Overview
Problem
Existing control devices for vessels with multiple propulsion units face challenges in preventing large engine speed fluctuations when synchronization of engine rotational speeds is cancelled, particularly due to significant throttle opening corrections during synchronization.
Innovation Solution
A control system that includes engine rotational speed detection devices for a reference and target propulsion units, which synchronizes engine speeds by correcting the throttle opening based on deviations, and reduces the throttle opening correction stepwise to the natural position when synchronization is cancelled, ensuring smooth engine speed transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the throttle opening is corrected to synchronize engine speeds, then the engine rotational speed synchronization is improved, but large engine speed fluctuations occur when synchronization is cancelled
Solution Approach 1:
The control system dynamically adjusts the throttle opening correction amount based on the current operating state. When synchronization is cancelled, the correction is reduced stepwise rather than abruptly, allowing the engine speed to transition smoothly. This dynamic adjustment resolves the contradiction by maintaining synchronization reliability while preventing speed fluctuations during cancellation.
Solution Approach 2:
The system changes the parameter of throttle opening correction amount from a fixed value to a variable that adapts to different operational phases. During synchronization, the correction amount is optimized for speed matching; when synchronization is cancelled, the correction amount is gradually reduced. This parameter change enables the system to maintain both synchronization accuracy and speed stability.
2Measurement precision
If the throttle opening correction is applied during synchronization, then the engine speed deviation is reduced, but sudden engine speed changes occur upon cancellation
Solution Approach 1:
The control system performs preliminary action by gradually reducing the throttle opening correction before complete cancellation of synchronization. This staged reduction allows the engine speed to adapt progressively, preventing sudden changes. The preliminary reduction of correction amount ensures both precise deviation control and smooth transition.
Solution Approach 2:
The system implements periodic action through stepwise reduction of the throttle opening correction over multiple control cycles. Instead of immediate cancellation, the correction is reduced in discrete steps, creating a periodic adjustment pattern that smooths the speed transition while maintaining precise control throughout the process.
Data Source
AI summary
A control device for propulsion units is adapted to synchronize the engine rotational speeds of a plurality of propulsion units arranged in a row on a vessel and operatively and electrically connected to two control levers that are positioned adjacent to each other. The control device synchronizes the engine rotational speeds by correcting the throttle opening of a target propulsion unit or units based on a deviation between the engine rotational speed of a reference propulsion unit and the engine rotational speed of the target propulsion unit. Upon cancellation of synchronization, the throttle opening correction is reduced stepwise from its corrected throttle opening to its natural throttle opening based on the position of the corresponding control lever. As such, large fluctuations in engine speeds are avoided upon cancellation of synchronization.