Electric Motor Cooling Flow Control for Low-Temperature Lubrication
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Solution Overview
Problem
Existing electric motor cooling systems require separate circuits for cooling and lubrication, increasing costs and complexity, and struggle with excessive refrigerant supply at low temperatures, which can lead to increased friction and inefficient temperature regulation.
Innovation Solution
A cooling method using two refrigerant systems where the first refrigerant is cooled through heat exchange with a second refrigerant, with controlled flow rates to the electric motor, reducing supply when temperatures are low to prevent excessive cooling and maintain lubrication, implemented using a heat exchanger and controlled pump operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate lubrication circuit is provided in addition to the cooling circuit, then the electric motor can be properly lubricated at low temperatures, but the device complexity and cost increase
Solution Approach 1:
The patent combines the cooling circuit and lubrication circuit into a single integrated refrigerant circulation system. The same refrigerant serves both cooling and lubrication functions, eliminating the need for separate circuits and reducing system complexity while maintaining reliable lubrication through controlled refrigerant distribution.
Solution Approach 2:
The refrigerant is designed to perform multiple functions simultaneously: it cools the electric motor and other components while also providing necessary lubrication. This multi-functional approach allows a single substance to replace what would traditionally require separate systems for cooling and lubrication.
2Temperature
If refrigerant flow rate is increased to cool the electric motor, then cooling efficiency improves, but lubrication performance deteriorates due to excessive cooling increasing viscosity
Solution Approach 1:
The system dynamically adjusts the refrigerant flow rate to the electric motor based on real-time temperature conditions. When the motor temperature is low, the flow rate is reduced to prevent excessive cooling that would increase viscosity and harm lubrication. When temperature rises, flow rate increases to provide adequate cooling, maintaining optimal balance between cooling efficiency and lubrication performance.
Solution Approach 2:
The control unit changes the flow rate parameter of the refrigerant based on temperature thresholds. By adjusting this key parameter dynamically, the system optimizes both cooling and lubrication functions, preventing the refrigerant from being overly cooled when motor temperature is already low, thus maintaining appropriate viscosity for effective lubrication.
3Manufacturing precision
If a flow rate control valve is added to regulate refrigerant distribution, then temperature control precision improves, but the number of components and installation space increase
Solution Approach 1:
The patent replaces traditional mechanical flow control valves with an electronically controlled system. The control unit regulates refrigerant flow rates through electronic control of circulation pumps and expansion valves, eliminating the need for additional mechanical flow rate control valves while achieving precise temperature control through software-based algorithms and sensor feedback.
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 eliminates the need for separate lubrication and cooling circuits, reduces parts count, lowers costs, and ensures efficient temperature management by adjusting refrigerant flow based on temperature thresholds, preventing excessive cooling and maintaining necessary lubrication.
Implementation Method 1
the first refrigerant is cooled by using heat exchange with a second refrigerant having a cooling target that is different from the first refrigerant
Data Source
AI summary
An electric motor is cooled by using a first refrigerant. The first refrigerant is cooled by heat exchange with a second refrigerant having a cooling target that is different from the first refrigerant, and the first refrigerant after being cooled by the heat exchange is supplied to the electric motor. The supply flow rate of the first refrigerant to the electric motor is reduced where a temperature of the first refrigerant is less than a first prescribed temperature as compared to where the temperature of the first refrigerant is greater than or equal to the first prescribed temperature. The supply flow rate of the first refrigerant is continuously reduced as long as a temperature of the second refrigerant is below a second prescribed temperature even after the temperature of the first refrigerant reaches the first prescribed temperature.