Traction Motor Cooling Loop Layout for Volatile Dielectric Coolant
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Solution Overview
Problem
Dielectric cooling liquids used in electric traction machines are more volatile, leading to excessive losses due to discharge of gaseous portions during air discharge in expansion tanks, which is not efficiently addressed by existing cooling systems.
Innovation Solution
A cooling system design where the heat exchanger is positioned downstream of the electric traction machine and the expansion tank is positioned upstream, utilizing a looped conduit system with a circulation pump to minimize volatility losses and maintain efficient temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a dielectric cooling liquid is used in the cooling system, then the cooling capacity is improved, but the volatility of the cooling liquid increases leading to excessive losses
Solution Approach 1:
The expansion tank is positioned upstream of the heat exchanger in the circulation path, so that the cooling liquid is cooled before reaching the expansion tank. This preliminary cooling action prevents the cooling liquid from becoming too warm and volatile, thereby reducing losses while maintaining effective cooling capacity.
2Temperature
If the expansion tank is positioned downstream of the heat exchanger, then the cooling liquid can be cooled effectively, but the gaseous portion of the cooling liquid is discharged during air discharge
Solution Approach 1:
The conventional arrangement is inverted by placing the expansion tank upstream of the heat exchanger rather than downstream. This inversion ensures that cooling liquid is cooled before it reaches the expansion tank, preventing volatile gaseous portions from being discharged during air discharge operations.
3Productivity
If the cooling liquid is circulated at high temperature, then the heat dissipation efficiency is improved, but the volatility and gaseous losses increase
Solution Approach 1:
The system applies preliminary cooling action by positioning the expansion tank upstream of the heat exchanger, cooling the liquid before it enters the expansion tank. This maintains lower temperatures in the expansion tank region, reducing volatility and gaseous losses while allowing the system to operate at high temperatures for efficient heat dissipation elsewhere in the circuit.
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
Significantly reduces the loss of dielectric cooling liquid by maintaining low temperatures in the expansion tank, ensuring effective temperature control and minimizing gaseous losses, while also allowing for efficient heat dissipation and temperature management of the electric traction machine.
Implementation Method 1
a circulation pump for conveying the first cooling liquid in the looped conduit system in a first circulation direction
Implementation Method 2
a first heat exchanger for dissipating heat from and/or supplying heat to the first cooling liquid to be circulated in the looped conduit system
Implementation Method 3
The second heat exchanger is configured for heat transfer between the second cooling liquid to be circulated in the second cooling circuit and the first cooling liquid to be circulated in the first cooling circuit
Data Source
AI summary
A cooling system for an electric traction machine includes a looped conduit system for conducting a first cooling liquid and a circulation pump for conveying the first cooling liquid in a first circulation direction. The cooling system includes an expansion tank filled at least partially with the first cooling liquid and a gas, and a motor input terminal for fluidically connecting the looped conduit system on an input side to the electric traction machine. The cooling system includes a motor output terminal for fluidically connecting the looped conduit system on an output side to the electric traction machine and a first heat exchanger for dissipating heat from and/or supplying heat to the first cooling liquid. In the first circulation direction, the first heat exchanger is arranged downstream of the electric traction machine and connected via the motor input and output terminal and upstream of the expansion tank.