Marine Propulsion Shift Control for Smooth Forward-Reverse Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing marine vessel propulsion control systems face challenges in managing the transition of the power transmission mechanism from a forward connection state to a reverse connection state, leading to potential engine stall or damage due to sudden load changes, especially when applied to vessels of varying lengths.
Innovation Solution
A marine vessel propulsion control system that calculates a simulated ship speed based on engine rotational speed and a scale conversion coefficient corresponding to vessel length, adjusting the timing of power transmission mechanism state changes to prevent load imbalances and ensure smooth transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the power transmission mechanism switches from forward connection state to reverse connection state directly, then the response speed is improved, but the engine may stall or the mechanism may be damaged due to sudden load changes
Solution Approach 1:
The control device introduces a predetermined time period delay before switching the power transmission mechanism from forward connection state to reverse connection state. This preliminary waiting period allows the engine to adjust to the upcoming load change, preventing sudden load reversals that could cause engine stall or mechanism damage while still maintaining relatively fast response capability.
2Device complexity
If a fixed time delay is used for state switching across all vessels, then the control logic is simple, but the switching timing is inappropriate for vessels of different lengths
Solution Approach 1:
The control device determines the predetermined time period dynamically based on the detected length of the watercraft. Longer vessels receive longer delay periods while shorter vessels receive shorter delay periods. This dynamic adjustment ensures that the state switching timing is appropriate for each vessel's specific characteristics, improving adaptability without significantly complicating the control logic.
3Speed
If the throttle valve opens immediately after switching to reverse connection state, then the propulsive force is generated quickly, but a large load is applied to the power transmission mechanism and engine
Solution Approach 1:
The control device waits for a predetermined time period after switching to reverse connection state before opening the throttle valve. This preliminary delay allows the power transmission mechanism and engine to adjust to the reverse connection without sudden full load application. The throttle valve then opens gradually or at a controlled rate, generating propulsive force while limiting the peak load on the mechanism.
Data Source
AI summary
A marine vessel propulsion control system includes a simulated ship speed calculator which calculates a simulated ship speed by multiplying an engine rotational speed when the ship travels forward in a propeller co-rotating state and the power transmission mechanism continues the forward connection state by a scale conversion coefficient corresponding to a ship length, and which decreases the simulated ship speed based together with elapse of time. A shift controller, in a case where the simulated ship speed is not equal to or less than a predetermined simulated ship speed threshold when the operation part is changed from the forward position to the neutral position and is subsequently changed to the reverse position, switch the state of the power transmission mechanism from the disconnection state to the reverse connection state after waiting for the simulated ship speed to become equal to or less than the simulated ship speed threshold.