Rotary Electric Machine Cooling System Variable Flow Control
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Solution Overview
Problem
Existing cooling systems for rotary electric machines do not optimize coolant flow rates according to vehicle speed, leading to excessive cooling at low speeds and inadequate cooling at high speeds, which can result in decreased performance and increased friction in power transmission mechanisms.
Innovation Solution
A cooling system with a pump that adjusts coolant flow rates based on rotational speed, featuring multiple coolant flow paths, pressure regulation, and flow rate regulation components, including a bypass flow path to optimize coolant flow according to vehicle speed, ensuring efficient cooling and lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a constant cooling flow rate is used from low to high vehicle speed, then cooling performance is maintained, but excessive cooling occurs at low speed leading to increased pump size and friction
Solution Approach 1:
The patent applies dynamics by making the cooling flow rate variable rather than constant. The pump flow rate changes according to vehicle speed, and the bypass flow path dynamically redirects coolant based on pressure differential. This resolves the contradiction by adapting cooling intensity to actual thermal conditions at different speeds, avoiding excessive cooling at low speed while ensuring adequate cooling at high speed.
Solution Approach 2:
The patent changes the parameter of coolant flow rate from fixed to variable. By using a bypass flow path that opens at high vehicle speeds, the system changes the flow rate parameter in response to operating conditions. This allows the cooling system to provide appropriate cooling intensity matching the thermal load at different speeds, reducing energy loss while maintaining cooling performance.
2Temperature
If cooling flow rate is increased for high vehicle speed, then cooling performance improves, but excessive cooling occurs at low vehicle speed
Solution Approach 1:
The system dynamically adjusts cooling flow rate based on vehicle speed conditions. At low speeds, the bypass flow path remains closed directing all coolant through the normal cooling circuit at lower flow rates, reducing friction. At high speeds, the bypass path opens to increase cooling flow rate, resolving the contradiction between cooling performance and friction.
Solution Approach 2:
The bypass flow path acts as an intermediary mechanism that mediates between the pump and the cooling circuits. It provides a conditional alternative flow path that activates only when needed (high vehicle speed), allowing the system to achieve high cooling flow rates without continuously operating the pump at high capacity, thus reducing friction during normal low-speed operation.
3Productivity
If a bypass flow path is added to optimize cooling flow rate, then cooling efficiency improves, but device complexity increases
Solution Approach 1:
The bypass flow path is designed to operate automatically based on pressure differential without external control. The high-speed opening mechanism responds self-service to operating conditions, opening when pressure differential indicates high vehicle speed. This simple automatic mechanism achieves complex cooling optimization without adding sophisticated control systems, balancing cooling efficiency with device complexity.
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 system enhances cooling performance at high vehicle speeds while reducing coolant flow at low speeds, preventing excessive cooling and maintaining efficient operation without increasing pump size or friction in power transmission mechanisms.
Implementation Method 1
a pump configured to increase and decrease a flow rate of a coolant according to a magnitude of a rotational speed of the rotary electric machine and pump the coolant
Implementation Method 2
a pressure regulation part provided in the first coolant flow path and configured to regulate a pressure in the first coolant flow path
Implementation Method 3
a flow rate regulation part provided at a position downstream than the pressure regulation part in the second coolant flow path and configured to regulate a flow rate of the coolant
Implementation Method 4
a first coolant flow path extending from the pump to the rotary electric machine and configured to guide the coolant to the rotary electric machine
Implementation Method 5
a flow path switching part provided in the third coolant flow path and configured to allow a flow of the coolant to the first coolant flow path when experiencing a pressure of a threshold or more
Data Source
AI summary
A cooling system includes a rotary electric machine, a pump that pumps coolant, a first coolant flow path that guides coolant to the rotary electric machine, a second coolant flow path branching off from the first coolant flow path, a pressure regulation valve provided in the second coolant flow path, a first orifice provided at downstream than the pressure regulation valve in the second coolant flow path in coolant flow direction, a third coolant flow path branching off from between the pressure regulation valve and the first orifice in the second coolant flow path and joining to a downstream than the branching position of the second coolant flow path in the first coolant flow path in coolant flow direction, and a switching valve provided in the third coolant flow path and that allows coolant flow to the first coolant flow path when experiencing a pressure of a threshold or more.