Counter-Rotating Impeller Marine Propulsion System
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Solution Overview
Problem
Conventional marine propulsion systems face issues such as high drag, cavitation, safety concerns due to exposed rotating blades, and reduced efficiency due to direct engine-drive connections, which limit their performance and control.
Innovation Solution
A marine propulsion system featuring counter-rotating impellers arranged parallel to the water surface, driven by counter-rotating gears, which are connected to a drive shaft through an input shaft or transmission, allowing for adaptable powerplant integration and eliminating the need for external water pumps, while providing lift and control surfaces for steering and trim control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional propellers or impellers rotate perpendicular to the water surface, then propulsion is achieved, but high drag levels occur due to excessive equipment surface below the waterline
Solution Approach 1:
The patent inverts the conventional orientation of propellers/impellers by rotating them parallel to the water surface instead of perpendicular to it. This inversion changes the rotation axis from horizontal to vertical, allowing the impeller blades to sweep through water in a vertical plane while the housing presents minimal surface area to the water flow, thereby reducing drag while maintaining propulsion capability
Solution Approach 2:
The patent transitions the propulsion mechanism from a horizontal rotation plane to a vertical rotation plane. By changing the dimension of rotation from perpendicular to parallel with the water surface, the system achieves propulsion through a different spatial configuration that reduces the wetted surface area of the housing while maintaining effective water displacement
2Loss of energy
If conventional propellers or impellers rotate perpendicular to the water surface, then propulsion is achieved, but high levels of cavitation occur due to inefficiency in the direction of rotation compared to water flow
Solution Approach 1:
The patent inverts the rotation orientation to align the impeller blade movement more effectively with natural water flow patterns. By rotating parallel to the water surface, the blades move through water in a manner that reduces abrupt pressure changes and vortex formation, thereby minimizing cavitation while improving propulsion efficiency
Solution Approach 2:
The patent changes the orientation parameter of the impeller rotation from perpendicular to parallel with the water surface. This parameter change fundamentally alters the interaction between the rotating blades and water flow, optimizing the pressure distribution and reducing cavitation-prone conditions while enhancing overall propulsion efficiency
3Productivity
If rotating blades are exposed in open water, then propulsion is achieved, but safety related issues arise
Solution Approach 1:
The patent merges the impeller blades with a fully enclosed housing structure, eliminating the exposure of rotating blades to the external water environment. The housing completely encloses the rotating components, allowing propulsion to occur internally while presenting a smooth, safe external surface that eliminates direct contact hazards with rotating blades
Solution Approach 2:
The patent extracts the rotating impeller blades from the external water environment and places them entirely within an enclosed housing. This separation removes the safety hazard of exposed rotating blades from the water-contact zone while maintaining the propulsion function within the protected internal chamber
4Device complexity
If a direct connection between engine and drive unit is used, then simplicity is achieved, but propeller speed is locked in relation to input speed, reducing efficiency under certain conditions
Solution Approach 1:
The patent introduces a variable ratio transmission mechanism between the engine and impeller drive system, replacing the fixed direct connection. This dynamic transmission allows the impeller speed to vary independently from the engine input speed, enabling optimization of propulsion efficiency across different operating conditions while maintaining manageable system complexity through standardized transmission components
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
This configuration enhances safety, efficiency, and control by reducing drag, mitigating cavitation, and allowing for variable speed ratios, while also providing cooling for the engine and minimizing equipment exposure below the waterline.
Implementation Method 1
a pair of impellers associated respectively with the pair of hull sides that rotate within respective impeller planes disposed generally parallel to the hull sides to convey water from at least one inlet though at least one outlet to provide thrust to the vessel
Implementation Method 2
The input gears may be designed such that the impeller rotation of the impellers draws water through the impellers and towards the aft (rear) portion of the vessel and into an output nozzle
Implementation Method 3
water pressure is available near the impeller output area which can be utilized to cool the engine in the case of an internal combustion engine
Data Source
AI summary
A marine vessel having a hull with a pair of opposite sides disposed at an angle with respect to one another, the opposite sides also disposed at an angle with respect to a water surface. A marine propulsion system is operatively coupled to the hull and includes a pair of impellers associated respectively with the pair of hull sides that rotate within respective impeller planes disposed generally parallel to the hull sides to convey water from at least one inlet though at least one outlet to provide thrust to the vessel. The marine propulsion system may also be contained within an outboard unit mounted to a transom of the vessel.