Outboard Motor Cooling with Dual Transmission-Driven Pumps
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Solution Overview
Problem
Existing outboard motors with electrically driven main pumps require additional space, increasing the motor's size due to the need for an electric motor, which is not efficient in terms of space utilization.
Innovation Solution
The use of a first pump driven by the drive shaft and a second pump driven by the propeller shaft, both connected to the transmission, to supply cooling water to the engine, eliminating the need for an electric motor-driven pump and reducing the motor's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a main pump is driven by an electric motor, then the pump can reliably supply cooling water to the engine, but the outboard motor size increases due to the space required for the electric motor
Solution Approach 1:
The pump system serves itself by utilizing the engine's own rotational power through the drive shaft and propeller shaft to drive the pumps, eliminating the need for a separate electric motor. The first pump is driven by the drive shaft and the second pump is driven by the propeller shaft, creating a self-contained cooling water supply system that does not require additional power sources.
Solution Approach 2:
The drive shaft and propeller shaft, which already serve primary propulsion functions, are made multi-functional by also driving the pumps for cooling water supply. This allows the existing rotating components to perform dual roles: power transmission for propulsion and power delivery for the cooling system, thereby eliminating the need for a dedicated electric motor.
2Adaptability or versatility
If an electric motor is added to drive the main pump, then the pump operation becomes independent of engine rotation, but the device complexity and space requirements increase
Solution Approach 1:
The pump drive system is merged with the existing propulsion system by using the drive shaft and propeller shaft that are already integral to the engine's operation. This consolidation eliminates the need for a separate electric motor and its associated control systems, reducing overall device complexity while maintaining reliable pump operation through the engine's rotational power.
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
Efficient cooling water supply to the engine is achieved while minimizing the outboard motor's size by utilizing pumps connected to the transmission, thereby reducing the overall dimensions compared to designs with electrically driven pumps.
Implementation Method 1
The first pump is below a lower end of the bracket. The first pump is connected to the transmission and operable to send cooling water to the engine through the cooling water passage. The second pump is driven by the driving force from the transmission and operable to send cooling water to the engine through the cooling water passage.
Data Source
AI summary
An outboard motor includes a bracket, an engine, an upper case, a lower case, a cavitation plate, a transmission, a cooling water passage, a first pump, and a second pump. The transmission includes a drive shaft and a propeller shaft. The cooling water passage is connected to the engine and located in the upper case and the lower case. The first pump is below a lower end of the bracket. The first pump is connected to the transmission and operable to send cooling water to the engine through the cooling water passage. The first pump is a non-positive displacement pump. The second pump is driven by a driving force from the transmission and operable to send the cooling water to the engine through the cooling water passage.