Marine Transmission Shift Control for Coordinated Multi-Drive Operation
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Solution Overview
Problem
Existing marine propulsion systems face challenges in efficiently shifting gears based on dynamic power requirements and vessel conditions, leading to suboptimal performance, fuel inefficiency, and uncoordinated shifting across multiple propulsion devices.
Innovation Solution
A method and system for shifting a multi-speed transmission in marine propulsion devices that determine the actual power level and transmission output shaft speed, comparing it to predefined shift thresholds, and controlling the gear shift accordingly, while also coordinating shifts across multiple devices to minimize noise, vibration, and harshness (NVH) effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gear shifting is controlled based on engine speed and load, then transmission performance is improved, but shifting coordination across multiple propulsion devices deteriorates
Solution Approach 1:
The patent combines multiple control parameters (engine speed, load, and power level) into a unified shifting control strategy. The controller integrates these parameters to make coordinated shifting decisions across multiple propulsion devices, ensuring that all devices shift gears in a synchronized manner rather than independently based on single parameters.
Solution Approach 2:
The system implements feedback control by continuously monitoring engine speed, load, and calculated power levels, then using this information to control gear shifting. The controller adjusts shifting timing based on real-time operating conditions and the shifting status of other propulsion devices, creating a closed-loop control system that coordinates shifting across the fleet.
2Ease of operation
If gear shifting is based on fixed thresholds, then control simplicity is improved, but fuel efficiency deteriorates
Solution Approach 1:
The patent transitions from static fixed thresholds to dynamic power-based thresholds. The controller calculates actual power levels based on real-time engine speed and load measurements, then uses these dynamic values to determine optimal shifting points. This allows the shifting strategy to adapt continuously to changing operating conditions, improving fuel efficiency while maintaining relatively simple control logic.
Solution Approach 2:
The system changes the control parameter from fixed engine speed thresholds to dynamic power levels derived from multiple parameters. By calculating power as a function of engine speed and load, the system creates adaptive thresholds that automatically adjust to operating conditions, reducing fuel consumption without significantly increasing control complexity.
3Productivity
If multiple propulsion devices shift independently, then individual device performance is improved, but overall system smoothness deteriorates
Solution Approach 1:
The controller merges the control of multiple independent propulsion devices into a coordinated system. By monitoring the collective operating conditions and shifting status of all devices, the controller synchronizes gear shifts across the fleet, ensuring that not all devices shift simultaneously but in a staggered, coordinated manner that reduces noise and vibration while maintaining individual performance.
Data Source
AI summary
A method for shifting a multi-speed transmission of a marine propulsion device between a first gear and a second gear each configured to transmit torque from a powerhead to a transmission output shaft. The method includes determining an actual power level requested for operating the marine propulsion device and measuring a transmission output shaft speed in which the transmission output shaft is rotating. The method further includes comparing the actual power level to a shift threshold, the shift threshold corresponding to expected power levels for operating the marine propulsion device as a function of the transmission output shaft speed of the transmission output shaft. The method further includes controlling the multi-speed transmission to shift when the actual power is outside the shift threshold.