Marine Propulsion Shaft Torque Compensation for Ambient Torsional Loads
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Solution Overview
Problem
Existing marine vessel propulsion systems face inefficiencies due to ambient torsional loads from waves, sea-state, and other external factors, leading to increased fuel consumption and costs, particularly in long journeys, and hybrid propulsion systems are costly and not optimally designed for reducing these effects.
Innovation Solution
A system utilizing an electric motor-generator, controller, and energy reservoir to predict and compensate for torsional loads by adjusting power flow, minimizing oscillatory loads on the shaft and engine, thereby optimizing fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If hybrid propulsion systems are used to improve fuel efficiency, then fuel consumption is reduced, but system cost increases and the system is not optimally designed for reducing ambient torsional loads
Solution Approach 1:
An electric motor-generator is introduced as an intermediary component between the main engine and propeller shaft. This mediator compensates for ambient torsional loads by providing counteracting torque, thereby protecting the main engine from load variations and improving fuel efficiency without requiring a complete hybrid propulsion system replacement
Solution Approach 2:
The system predicts future ambient torsional loads based on historical data and wave patterns, then proactively applies compensating torque through the electric motor-generator before the loads affect the main engine. This preliminary action prevents fuel efficiency degradation rather than reacting to it after the fact
2Stability of the object's composition
If the main engine adjusts fuel injection to maintain constant RPM under varying torsional loads, then engine speed stability is maintained, but fuel efficiency deteriorates
Solution Approach 1:
The electric motor-generator serves as a buffer that absorbs ambient torsional loads, allowing the main engine to operate at constant RPM without continuously adjusting fuel injection. The mediator handles the load variations, enabling the main engine to maintain optimal operating conditions for fuel efficiency
Solution Approach 2:
The system uses the main engine's own electrical power output to operate the electric motor-generator, creating a self-service arrangement where the engine's excess electrical capacity is utilized to compensate for its mechanical load variations, improving overall efficiency without external energy sources
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system reduces fuel consumption and costs by actively compensating for torsional loads, creating a less oscillatory environment for the engine, thus improving propulsion efficiency and reducing unnecessary fuel usage.
Implementation Method 1
an electric motor-generator configured to provide power to the shaft or take out power from the shaft
Data Source
AI summary
A system for alleviating variations in torsional loads applied to a shaft coupled to a main engine of a marine vessel, said shaft is coupled to a propeller of the marine vessel, the system comprising an electric motor-generator configured to provide power to the shaft or take out power from the shaft; a controller coupled to the electric motor-generator said controller is configured to execute instructions, comprising: measuring a group of values that are indicative of torsional loads applied on a shaft of the marine vessel over time; creating a time-based series of values that represent a predictive time-based torsional loads on the marine vessel; collecting readings indicative of power provided by a main engine of the marine vessel; computing an intervention time series of power values to be outputted by the electric motor-generator; wherein the electrical power outputs the intervention time series values of power to the shaft.