Hybrid Pod Drive With Pod-Integrated Electric Machine Cooling
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Solution Overview
Problem
Existing marine drive units lack compact, streamlined designs with high reliability and wide applicability, particularly in hybrid propulsion systems combining combustion engines with electric machines.
Innovation Solution
A hybrid pod drive design featuring a combustion engine with a horizontal crank shaft, two electric machines, and transmission units with bevel gear sets, allowing for compact, streamlined dimensions and efficient power transmission, with one electric machine integrated within a pod housing for cooling and protection, and separate control units for independent operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hybrid propulsion device combines a combustion engine with electric machines, then environmental performance and efficiency are improved, but the device complexity and space requirements increase
Solution Approach 1:
The patent combines the combustion engine, first electric machine (motor), and second electric machine (generator) into a single integrated hybrid propulsion device. The combustion engine and both electric machines share common mounting structures, control systems, and power transmission components, merging multiple functions into one compact unit that delivers improved environmental performance without proportionally increasing complexity
Solution Approach 2:
The first electric machine serves dual purposes: it can operate as a motor to assist propulsion and as a generator for regenerative braking. The second electric machine primarily functions as a generator for energy recovery. This multi-functionality reduces the need for separate dedicated components, thereby improving environmental performance while controlling device complexity
2Volume of moving object
If the first electric machine is arranged inside the pod housing, then the design becomes more compact and streamlined, but cooling requirements increase
Solution Approach 1:
The first electric machine is nested inside the pod housing, with its stator mounted on the inner surface of the pod housing wall. This nesting arrangement utilizes the existing pod housing structure as part of the electric machine assembly, achieving a compact streamlined design while the pod housing itself can serve as a thermal management pathway
Solution Approach 2:
The patent converts the potentially harmful effect of waste heat into a beneficial cooling mechanism. The pod housing, which would normally be a barrier to heat dissipation, is designed to allow ambient water to cool the first electric machine from the outside, transforming the housing into a heat exchange surface that actively removes heat from the enclosed electric machine
3Volume of stationary object
If the combustion engine is arranged horizontally inside the hull, then the installation space is optimized, but the power transmission to the vertical propeller shaft becomes more complex
Solution Approach 1:
The patent merges the horizontal crankshaft of the combustion engine with the vertical propeller shaft through an integrated transmission assembly. The engine coupling directly connects the horizontal crankshaft to the drive shaft, which then feeds into the bevel gear set that converts horizontal motion to vertical motion, combining multiple transmission functions into a compact unified structure
Solution Approach 2:
The patent introduces an engine coupling as an intermediary component between the horizontal crankshaft and the drive shaft. This coupling includes elastic elements that accommodate misalignment and transmit power efficiently, serving as a mediator that simplifies the connection between components with different orientations and reduces the overall complexity of the power transmission system
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
Enables efficient, reliable, and versatile operation with zero emissions and reduced mechanical wear, supporting various modes including electric-only propulsion and hybrid power for enhanced efficiency and emissions reduction.
Implementation Method 1
The engine coupling may comprise at least one elastic element to compensate for radial, axial, or angular offset and to provide for a damping effect
Implementation Method 2
the ambient water has a cooling effect on the first electric machine inside the pod housing
Implementation Method 3
the ambient water has a cooling effect on the first electric machine inside the pod housing
Data Source
Figure 1
Figure 2
AI summary
Hybrid pod drive (1, 102) comprising a combustion engine (2) with a crank shaft (3) which is connected to a drive shaft (4), an upper transmission unit (5) to transmit the power from the drive shaft (4) to a vertical shaft (6), a lower transmission unit (7) to transmit the power from the vertical shaft (6) to a horizontal propeller shaft (8). The hybrid pod drive (1, 102) further comprising a first electric machine (10) with a first rotor shaft (11) and a second electric machine (20) with a second rotor shaft (21). The first rotor shaft (11) is arranged coaxial to the propeller shaft (8) and the first rotor shaft (11) is permanently connected to the propeller shaft (8). The second rotor shaft (21) is permanently connected to the drive shaft (4).