Marine Propulsion Shift Control via Linkage Position Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing marine propulsion systems experience significant noise and shock during gear shifts due to the impact between moving parts, particularly in the clutch, which is exacerbated by engine speed, leading to increased load on the shift mechanism and inefficient shifting processes.
Innovation Solution
A shift control system that senses the position of a shift linkage and communicates this information to a control circuit to modify thresholds for initiating engine speed changes, enabling a shift interrupt control strategy that briefly lowers engine speed to reduce noise and load, and actively adjusts these thresholds based on throttle valve position to optimize shift timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If engine speed is maintained high during gear shifts, then power delivery is maintained, but noise and shock increase due to impact between moving parts
Solution Approach 1:
The control circuit detects shift linkage position in advance and initiates engine speed reduction before the actual gear shift occurs. By sensing the shift linkage position and triggering the speed reduction prematurely, the system prepares the engine to absorb the shift impact without causing noise or shock, while maintaining power delivery through controlled timing of the speed reduction.
Solution Approach 2:
The system dynamically changes the engine speed parameter based on the detected shift linkage position. When the shift linkage reaches a predetermined position indicating an impending gear shift, the control circuit modifies the engine speed parameter by reducing it to a lower level, thereby minimizing the impact and noise during the actual shift event.
2Object-affected harmful factors
If engine speed is reduced during gear shifts, then noise and shock are decreased, but shift timing may be delayed
Solution Approach 1:
The control circuit continuously monitors the shift linkage position and uses this feedback to determine the optimal timing for engine speed reduction. By sensing the actual position of the shift linkage and comparing it to predetermined positions, the system adjusts the speed reduction timing to occur just before the gear shift, ensuring minimal delay while maximizing noise and shock reduction.
3Measurement precision
If shift linkage position is sensed continuously, then shift timing precision is improved, but system complexity increases
Solution Approach 1:
The existing shift linkage mechanism, which is already present in the marine propulsion system for gear shifting, is utilized to provide position sensing functionality. The control circuit leverages the natural movement and positioning of the shift linkage during normal operation to detect shift events, eliminating the need for separate, dedicated sensing mechanisms and thereby avoiding additional system complexity.
Data Source
AI summary
Systems and methods are for controlling shift in a marine propulsion device. A shift sensor outputs a position signal representing a current position of a shift linkage. A control circuit is programmed to identify an impending shift change when the position signal reaches a first threshold and an actual shift change when the position signal reaches a second threshold. The control circuit is programmed to enact a shift interrupt control strategy that facilitates the actual shift change when the position signal reaches the first threshold, and to actively modify the first threshold as a change in operation of the marine propulsion device occurs.