Electric Machine Cooling via Segmented Coolant Jacket and Sump

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Solution Overview

Problem

Electric machines generate significant heat during operation, which can impact their performance and lifespan, and existing cooling solutions often fail to effectively manage this heat, particularly in the stator and rotor assemblies.

Innovation Solution

An electric machine module with a housing that includes a coolant jacket for a first coolant and a coolant sump for a second coolant, where the coolant sump is in thermal communication with the coolant jacket and positioned to prevent material amounts of the second coolant from entering the air gap between the stator and rotor assemblies, enhancing heat transfer and cooling efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a coolant system is implemented to remove heat from the electric machine, then the operating temperature is reduced and performance is improved, but the risk of coolant entering the air gap increases, causing shearing and performance degradation

Engineering Contradiction:

Improveoperating temperatureVSAvoidcoolant shearing

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The cooling system is segmented into two distinct zones: a coolant jacket containing the first coolant for heat removal, and a coolant sump containing the second coolant for thermal management. This segmentation prevents the coolants from entering the air gap while maintaining effective cooling through controlled thermal communication between the zones.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The housing structure acts as an intermediary element that provides thermal communication between the coolant jacket and coolant sump without allowing direct fluid communication. This intermediary structure enables heat transfer while preventing coolant leakage into the air gap, resolving the contradiction between cooling effectiveness and reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of energy

If a coolant jacket is used to cool the electric machine components, then heat transfer efficiency is improved, but the complexity of the cooling system increases

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidcooling system complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The housing is designed to combine multiple functions: it serves as the structural enclosure for the electric machine, the coolant jacket, and the coolant sump. By merging these components into a single integrated housing structure, the patent reduces overall system complexity while maintaining effective heat transfer capabilities through the coordinated action of the jacket and sump.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The housing structure is designed as a multi-functional component that simultaneously provides mechanical support, contains the cooling system, and facilitates thermal management. This universal design approach eliminates the need for separate cooling system components, thereby reducing complexity while preserving heat transfer efficiency.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If the coolant sump is positioned to prevent second coolant from entering the air gap, then reliability is improved, but the thermal communication between the sump and jacket may be reduced

Engineering Contradiction:

Improveprevention of coolant entryVSAvoidthermal communication efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent replaces direct mechanical fluid communication between the coolant sump and jacket with thermal communication through the housing structure. This substitution allows the system to maintain reliable prevention of coolant entry into the air gap while still achieving effective thermal management through heat conduction through the housing material.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical 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

The solution effectively transfers thermal energy from the electric machine components to the coolants, improving performance, reducing operating temperatures, and increasing the durability and efficiency of the electric machine, while minimizing complications like coolant shearing and air introduction.

Implementation Method 1

the housing can include at least a portion of a coolant jacket, which can be configured to contain a first coolant... the coolant sump can be in thermal communication with the coolant jacket

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the coolant sump can be in thermal communication with the coolant jacket... capable of containing a second coolant that is different from the first coolant

Methodology Applied

Scientific EffectThermal communication: Conduction (thermal)

Data Source

PatentUS8803380B2Electric machine module cooling system and method

Publication Date: 2014.08.12 BORGWARNER INC

AI summary

Embodiments of the invention provide an electric machine module. The module can include a housing that can define a machine cavity. The housing can include a coolant jacket that contains a first coolant. A coolant sump can be in fluid communication with the machine cavity and can contain a second coolant that is different than the first coolant. The coolant sump can be in thermal communication with the coolant jacket. An electric machine can be positioned within the machine cavity. The electric machine can include a stator assembly, a rotor assembly, and a shaft. The module can also include at least one coolant channel, at least one shaft channel, and at least one rotor channel.