Ship Propulsion System Segmentation for Engine Room Space
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Solution Overview
Problem
The existing ship propulsion systems face challenges in increasing ship speed without enlarging the main engine, which leads to space constraints in the engine room and reduced maintenance space, ultimately affecting propulsion performance and fuel economy.
Innovation Solution
A ship propulsion system that includes a main generator, an electric power distribution unit, a first electric motor driving a main propeller, a second electric motor driving a stern-side propeller, and a control unit that switches between electric motor and main engine operation based on thrust requirements, allowing the electric motor to compensate for main propeller shortfall and optimize power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the main engine size is increased to raise ship speed, then propulsion power is improved, but the space occupied in the engine room increases and maintenance space is reduced
Solution Approach 1:
The propulsion system is segmented into two independent drive sources: the main engine connected to the main propeller, and the electric motor connected to the stern-side propeller. This segmentation allows the main engine to be sized for normal operation while the electric motor provides additional power when needed, avoiding the need to oversize the main engine for peak speed requirements.
Solution Approach 2:
The electric power distribution unit serves multiple functions: it distributes power to the stern-side propeller for propulsion assistance, and can also power other ship systems. The electric motor system acts as both a propulsion assistant and a potential backup drive, providing multi-functionality that reduces the need for a larger main engine.
2Ease of repair
If the engine room is expanded to ensure maintenance space, then maintenance accessibility is improved, but the ship width must be increased which worsens propulsion performance and fuel economy
Solution Approach 1:
By segmenting the propulsion system into main engine and electric motor components, maintenance can be performed on smaller, modular units rather than a single large engine. The electric motor and its control systems can be maintained separately from the main engine, improving accessibility without requiring a larger engine room.
Solution Approach 2:
The electric power distribution unit acts as an intermediary that manages power flow between the main generator, electric motor, and various ship systems. This intermediary structure allows for modular maintenance of power distribution components without affecting the main engine operation, improving maintenance accessibility while maintaining compact engine room layout.
3Use of energy by moving object
If the shaft generator is used for normal navigation, then fuel economy is improved, but the ship speed cannot be raised when operation delay occurs
Solution Approach 1:
The system dynamically switches between operating modes: during normal navigation, the shaft generator powers the electric motor for assisted propulsion; when speed increase is needed, the system transitions to using the main generator to power the electric motor, providing on-demand speed enhancement without compromising normal fuel economy.
Solution Approach 2:
The system changes operational parameters based on requirements: the power source for the electric motor changes from shaft generator (fuel-efficient mode) to main generator (high-power mode), and the pitch of the main propeller can be adjusted independently of the stern-side propeller, allowing flexible optimization of both fuel economy and speed according to operational conditions.
4Speed
If the main generator supplies power to the electric motor for speed increase, then ship speed can be raised, but the main engine size must be increased to handle the additional load
Solution Approach 1:
The propulsion power is segmented between the main engine driving the main propeller and the electric motor driving the stern-side propeller. This segmentation allows the main engine to be sized for base propulsion requirements, while the electric motor provides additional power for speed enhancement, eliminating the need to oversize the main engine for peak speed scenarios.
Solution Approach 2:
The electric motor substitutes for part of the mechanical propulsion function that would otherwise require a larger main engine. By replacing direct mechanical coupling with an electrical power transmission system, the main engine can operate at optimal size while the electric motor provides flexible power augmentation when speed increase is required.
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 enables high-performance propulsion without increasing the main engine size, reducing initial costs and maintaining efficient fuel economy while ensuring adequate maintenance space and propulsion performance.
Implementation Method 1
a first electric motor allowing a first rotary shaft to be driven to rotate by the electric power input via the electric power distribution unit
Implementation Method 2
a second electric motor allowing a second rotary shaft to be driven to rotate by the electric power input via the electric power distribution unit
Implementation Method 3
the first electric motor has a generator generating electric power from the rotation of the first rotary shaft attributable to output of the main engine
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Provided is a ship propulsion system such that an increase in the size of a main engine can be minimized. The ship propulsion system (1) is equipped with: main generators (10A, 10B, 10C) that supplies power to the interior of a ship; a power distribution unit (11) that distributes the power of the main generators (10A, 10B, 10C); a first electric motor (21) that rotatably drives a first rotary shaft (27) with the power input through the power distribution unit (11); a main propeller (24) that rotates along with the first rotary shaft (27); a second electric motor (15) that rotatably drives a second rotary shaft (17) with the power input through the power distribution unit (11); and a stern-side propeller (16) that is disposed on the stern side of the main propeller (24) and rotates along with the second rotary shaft (17).