Hybrid Engine-Generator Water Cooling for Low-Weight Drones

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Solution Overview

Problem

Existing cooling systems for reciprocating engines and generators in drones are inefficient and cumbersome, with water-cooling methods being more effective but complex and heavy, while air-cooling methods are less efficient for generators.

Innovation Solution

An integrated hybrid power apparatus that combines a water-cooling reciprocating engine and generator, featuring a water-cooling system with a cooling fin and water jacket to circulate coolant, reducing size, weight, and vibration, and allowing the generator rotor to function as a flywheel for stable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If water-cooling method is used for reciprocating engine, then cooling efficiency is improved, but system complexity and weight increase

Engineering Contradiction:
Improvecooling efficiencyVSAvoidsystem complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent merges the cooling systems of the reciprocating engine and generator into a single integrated water-cooling system. The coolant flows through both the engine water jacket and generator water jacket, combining two separate cooling systems into one unified system, thereby reducing overall complexity while maintaining effective cooling for both components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The water-cooling system serves multiple functions simultaneously: it cools the reciprocating engine through the engine water jacket and cools the generator through the generator water jacket. This multi-functional approach eliminates the need for separate cooling systems, reducing weight and complexity while improving overall cooling efficiency.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Device complexity

If air-cooling method is used for generator, then system simplicity is improved, but cooling efficiency deteriorates

Engineering Contradiction:
Improvesystem simplicityVSAvoidcooling efficiency
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The patent applies water-cooling to the generator by integrating it with the engine's water-cooling system. The generator water jacket receives coolant from the engine water jacket, allowing efficient heat removal from the generator without requiring a separate air-cooling system, thus maintaining simplicity while improving cooling efficiency.

Inventive Principle:
Principle #5Merging (Combining)

3Temperature

If separate cooling systems are used for engine and generator, then cooling effectiveness is improved, but weight and size increase

Engineering Contradiction:
Improvecooling effectivenessVSAvoidsystem weight
Core Design Contradiction:
TemperatureVSWeight of moving object

Solution Approach 1:

The patent combines the engine cooling system and generator cooling system into a single integrated water-cooling system. The coolant circulates through both the engine water jacket and generator water jacket, allowing effective cooling of both components while sharing common cooling infrastructure, thereby reducing overall system weight and size.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated water-cooling system performs multiple cooling functions simultaneously for both the reciprocating engine and generator. This multi-functional design eliminates redundant components and reduces overall system weight while maintaining effective cooling for both heat-generating components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 integrated system simplifies the engine-generator driving system, enhances cooling efficiency, reduces weight and vibration, and enables stable operation by utilizing an integral water-cooling system that minimizes cooling losses and improves overall performance.

Implementation Method 1

a cooler configured to cool the generator and the engine. The cooler may perform water-cooling that allows a coolant to circulate in the generator and the engine

Methodology Applied
Scientific EffectWater-cooling: Convection

Implementation Method 2

a cooling fin protruding to an inner side of the stator; and a generator water jacket configured to surround the cooling fin on the inner side of the stator and form a coolant flow path inside

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Data Source

PatentEP3832087B1Integrated hybrid power apparatus
Publication Date: 2023.12.20 KOREA AEROSPACE RES INST
  • EP3832087B1 patent drawingFigure 1
  • EP3832087B1 patent drawingFigure 2
  • EP3832087B1 patent drawingFigure 3

AI summary

An integrated hybrid power apparatus provided in a flying body includes a generator including a stator and a rotor, at least one engine disposed adjacent to the generator and including a cylinder, and a cooler configured to cool the generator and the engine and perform water-cooling that allows a coolant to circulate in the generator and the engine.