Closed-Loop Ship Speed Control With Fuel Injection Feedback
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Solution Overview
Problem
Current ship speed control systems are open-loop, leading to instability and inefficiency due to the nonlinear relationship between propeller speed and ship speed, which is affected by sea conditions, resulting in unstable navigation and potential engine overload.
Innovation Solution
A closed-loop automatic control system for ship speed, incorporating detection feedback, outer-loop control, middle-loop main engine speed control, and inner-loop fuel injection quantity control, utilizing algorithms and modules to stabilize ship speed and prevent engine overload.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If open-loop control is used to simplify the control system, then device complexity is reduced, but ship speed stability deteriorates due to the nonlinear relationship between propeller speed and ship speed affected by sea conditions
Solution Approach 1:
The patent implements a closed-loop control system that continuously measures actual ship speed and compares it with the target speed, then adjusts the main engine speed accordingly. This feedback mechanism resolves the contradiction by maintaining speed stability without requiring overly complex control architecture, as it builds upon the existing open-loop structure with added feedback loops.
Solution Approach 2:
The control system dynamically adjusts the main engine speed based on real-time sea conditions and ship speed measurements. Rather than using a fixed control strategy, the system adapts its control parameters according to changing conditions, resolving the instability caused by nonlinear propeller-speed to ship-speed relationships while keeping the control structure manageable.
2Stability of the object's composition
If main engine speed is increased to maintain ship speed against wind and waves, then ship speed stability is improved, but main engine overload and black smoke occur due to increased resistance
Solution Approach 1:
The control system uses feedback from actual speed measurements to adjust engine speed only to the extent necessary to maintain target ship speed. This prevents excessive engine loading and black smoke by avoiding unnecessary speed increases that would occur in open-loop control when resistance increases.
Solution Approach 2:
The system changes the control parameter from fixed engine speed to variable engine speed based on actual ship speed measurements. This allows the engine to operate at optimal speeds that maintain ship speed stability without causing overload or excessive emissions.
3Ease of operation
If the correspondence table between ship speed and main engine speed is used to simplify control, then ease of operation is improved, but measurement precision deteriorates because the ideal relationship changes due to wind, waves, and dirty hull
Solution Approach 1:
The system replaces the static correspondence table with a dynamic feedback control mechanism that continuously measures actual ship speed and adjusts engine speed accordingly. This maintains ease of operation through automatic control while dramatically improving accuracy by adapting to changing sea conditions and hull status.
Solution Approach 2:
The control system transitions from a static speed correspondence table to a dynamic control strategy that continuously adapts to changing conditions. This dynamic approach preserves operational simplicity through automation while achieving high precision in speed control despite varying wind, waves, and hull conditions.
4Stability of the object's composition
If closed-loop control is implemented to improve ship speed stability, then ship speed stability is improved, but device complexity increases due to the need for real-time feedback and multiple control loops
Solution Approach 1:
The control system is segmented into distinct functional modules: an outer loop for ship speed control and an inner loop for main engine speed control. This segmentation manages complexity by organizing the closed-loop control into manageable, hierarchical components rather than a monolithic complex system.
Solution Approach 2:
The dual-loop control structure uses dynamic hierarchy where the outer loop sets reference speeds and the inner loop executes precise engine control. This dynamic segmentation resolves the complexity issue by allowing each loop to operate semi-independently while maintaining overall system stability and performance.
Data Source
AI summary
A closed-loop automatic control system for ship speed and a method are provided, including the following steps: obtaining feedback information through a detection feedback module, and generating a final effective main engine speed order nE* through an outer-loop control module; through the middle-loop control module, the main engine speed order nE* is compared with the main engine speed n by the speed deviation Δn, which uses PID and other control algorithms, the final effective main engine fuel quantity order LS* is generated; through the inner-loop control module, generating the fuel quantity deviation ΔL between the main engine fuel quantity order LS* and fuel quantity feedback signal L into an optimized fuel quantity value S; and completing the closed-loop adjustment of fuel injection quantity (FIQ).