Engine-Mounted Motor Control Layout for Dual Cooling

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Solution Overview

Problem

The integration of a control section in the cooling air path of a rotary electric machine unit leads to reduced cooling efficiency of the internal combustion engine and increases the number of components, hindering cost reduction and size reduction.

Innovation Solution

The control section is positioned between the internal combustion engine and the motor section, with at least a part exposed to the engine's cooling air path, functioning as a cooling element to improve engine cooling efficiency while reducing component count.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the control section is disposed in the cooling air path of the internal combustion engine, then the control section can be cooled effectively, but the cooling efficiency of the internal combustion engine is degraded

Engineering Contradiction:
Improvecooling efficiency of control sectionVSAvoidcooling efficiency of internal combustion engine
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The control section is positioned as an intermediary component between the internal combustion engine and the motor section. It serves dual purposes: acting as a heat dissipation component for itself while simultaneously functioning as a cooling element for the engine by being exposed to the engine's cooling air path, thereby mediating between its own cooling needs and the engine's cooling requirements

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If the control section is disposed in the cooling air path, then cooling of the control section is achieved, but the number of components increases preventing cost reduction and size reduction

Engineering Contradiction:
Improvecooling efficiency of control sectionVSAvoidnumber of components
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The control section is merged with the structural assembly of the engine and motor section, eliminating the need for separate cooling components or additional housing structures. By integrating the control section into the existing mechanical assembly and exposing it to the cooling air path, the design achieves cooling functionality without adding extra components, thereby reducing overall device complexity and cost

Inventive Principle:
Principle #5Merging (Combining)

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 cooling efficiency of the internal combustion engine without degrading the control section's cooling efficiency, facilitating cost reduction and size reduction of the rotary electric machine unit.

Implementation Method 1

the control section is provided such that at least a part of the control section is exposed to a cooling air path of the internal combustion engine

Methodology Applied
Scientific EffectHeat sink: Heat Sink

Implementation Method 2

discharge heat that the control board generates to the inside of the cooling air path

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3624313B1Dynamo-electric machine unit
Publication Date: 2025.11.05 MITSUBA CORP
  • EP3624313B1 patent drawingFigure 1
  • EP3624313B1 patent drawingFigure 2
  • EP3624313B1 patent drawingFigure 3

AI summary

A rotary electric machine unit (1) includes: a motor section (10) that has a stator (12), around which a coil (11) is wound, and a rotor (13) that faces the stator (12) and is secured to a crankshaft (52) of the engine; and a control section (30) that has a control board that controls power distribution to the stator (12), the rotary electric machine unit (1) is used to drive the engine (50), the control section (30) is secured to the engine (50) and is provided such that at least a part of the control section (30) is exposed to a cooling air path (A) of the engine (50), and the motor section (10) is disposed on a side opposite to the engine (50) with the control section (30) interposed therebetween.