Electric Machine Cooling via Rotating Agitator Coolant Recirculation
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Solution Overview
Problem
Hybrid vehicle electric motors generate heat, which is not efficiently removed, leading to reduced lifespan and operating efficiency.
Innovation Solution
An electric machine module with a rotor and stator design that includes an agitator member to recycle coolant for enhanced cooling, allowing multiple passes over the stator end turns, increasing heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional single-pass cooling system is used, then the system is simple, but heat removal efficiency is insufficient
Solution Approach 1:
The coolant is continuously recirculated through the cooling system, passing multiple times over the stator end turns to continuously remove heat. The agitator member ensures the coolant remains in continuous motion, maximizing heat transfer efficiency throughout operation.
Solution Approach 2:
The agitator member acts as an intermediary component that actively manipulates the coolant flow. It uses rotational motion to splash and redirect coolant onto the stator end turns, enhancing heat transfer without requiring complex pumping systems.
2Reliability
If coolant flows directly from stator end turns without recirculation, then the system is simple, but cooling effectiveness is reduced
Solution Approach 1:
The coolant circulation creates a continuous cooling action that persists throughout electric machine operation. By repeatedly passing coolant over the stator end turns, the system maintains effective heat removal, extending component lifespan and improving reliability.
Solution Approach 2:
The cooling system uses the electric machine's own rotational energy to drive the agitator member, which in turn recirculates the coolant. This self-powered approach enhances cooling effectiveness without requiring external power sources or complex control systems.
3Temperature
If the coolant is not recirculated, then the device complexity is low, but heat dissipation is insufficient
Solution Approach 1:
The rotating agitator member creates mechanical disturbance and splashing action in the coolant, enhancing convective heat transfer. This mechanical agitation prevents stagnant zones and ensures thorough coolant contact with heated surfaces, maximizing heat dissipation efficiency.
Solution Approach 2:
The system uses hydraulic principles to circulate coolant through the cooling channels and over the stator end turns. The agitator member leverages rotational kinetic energy to move and distribute the coolant fluid, providing efficient heat transfer through fluid dynamics.
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 extends the lifespan and improves the operating efficiency of the electric machine by maximizing heat removal through a multiple-pass coolant recycling mechanism.
Implementation Method 1
directing the coolant toward the stator end turns... for cooling
Implementation Method 2
returning a portion of the coolant which flows past the stator end turns back toward the stator end turns for cooling using a rotating agitator member
Data Source
AI summary
Embodiments of the invention provide an electric machine module and a method for cooling an electric machine. The apparatus and method include providing the electric machine including a rotor and a stator with stator end turns and enclosing at least a portion of the electric machine within a housing. The method also includes introducing a coolant into a machine cavity, directing the coolant toward the stator end turns, and returning a portion of the coolant which flows past the stator end turns back toward the stator end turns using a rotating agitator member operatively coupled to the rotor.