Marine Transmission Shift Timing Using Clutch Pressure Feedback
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Solution Overview
Problem
Marine propulsion devices experience noise, vibration, and harshness (NVH) issues during power shifting from one gear to another, particularly when upshifting from a first gear to a second gear, due to inconsistent pressure control and clutch engagement timing, which can lead to damage and an unpleasant operator experience.
Innovation Solution
A method for shifting a multi-speed transmission that involves using pressure sensors to measure clutch pressures and a controller to adjust the delay between clutch actuations, ensuring the pressures intersect within a specific threshold range to achieve a smooth and efficient power shift, thereby minimizing NVH and extending transmission life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If clutch actuation delay is fixed without adjustment, then the shifting control is simple, but the pressure intersection becomes inconsistent causing NVH issues and potential damage
Solution Approach 1:
The system measures actual clutch pressures during shifting using pressure sensors, compares the pressure intersection point to a target range, and adjusts the clutch actuation delay accordingly. This closed-loop feedback ensures reliable pressure intersection while maintaining simple overall control architecture.
Solution Approach 2:
The clutch actuation delay is transformed from a fixed static parameter to a dynamic adjustable parameter that adapts based on measured pressure characteristics. This allows the system to optimize shifting behavior for different operating conditions while preventing NVH issues and damage.
2Object-affected harmful factors
If pressure control is not precisely monitored, then the shifting mechanism is simpler, but inconsistent pressure intersection causes NVH and damage
Solution Approach 1:
Pressure sensors provide real-time feedback on clutch pressure during shifting. The controller monitors the pressure intersection point and uses this information to adjust the actuation delay, ensuring the intersection occurs within the target range and preventing NVH and damage.
Solution Approach 2:
The system replaces purely mechanical pressure control with an electronically controlled adjustment mechanism. The controller modifies the clutch actuation timing based on electronic pressure sensor data, enabling precise control of pressure intersection to eliminate harmful NVH effects.
3Ease of operation
If clutch actuation timing is not optimized, then the shifting process is faster, but inconsistent timing causes pressure intersection issues and NVH
Solution Approach 1:
The clutch actuation delay is made dynamically adjustable based on measured pressure characteristics. By optimizing this timing parameter, the system achieves smooth pressure intersection and quiet shifting while maintaining efficient shift duration across different operating conditions.
Data Source
AI summary
A method for shifting a multi-speed transmission for transmitting rotation between an input shaft and an output shaft for a marine vessel. The method includes providing a multi-speed transmission having first and second gears engaged by actuating first and second clutches, and providing first and second pressure sensors that measure first and second pressures within the first and second clutches, respectively. The method further includes performing a first shift from the first gear to the second gear by de-actuating the first clutch a first delay after the second clutch is actuated, then measuring the first and second pressures and determining a first shift pressure at which the first and second pressures are substantially equal while performing the first shift. The method further includes comparing the first shift pressure to a first pressure threshold range and adjusting the first delay when the first shift pressure is outside the first pressure threshold range.