Dual-Circuit Powertrain Cooling With Heat Exchanger Bypass
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Solution Overview
Problem
The miniaturization of electric vehicle powertrains is hindered by inefficient heat dissipation, as increasing fin density or cooling flow to manage high heat consumption density leads to increased costs and volume, and conventional cooling systems face limitations in improving heat dissipation capability without compromising flow resistance or increasing hardware costs.
Innovation Solution
A temperature control system with a dual cooling circuit configuration, including a water-cooling circuit and an oil-cooling circuit, connected via an oil-water heat exchanger with a bypass branch, allowing for adjustable flow distribution via a valve to optimize heat dissipation efficiency across components, particularly the inverter and motor, by controlling the percentage of flow through the bypass pipe based on heat generation power and operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the fin density of the heat dissipation plate of the inverter is increased to improve heat dissipation capability, then the heat dissipation efficiency is improved, but hardware costs and process costs are increased
Solution Approach 1:
The patent divides the cooling system into two independent circuits: an oil-cooling circuit for the inverter and a water-cooling circuit for the motor. This segmentation allows each circuit to be optimized independently, avoiding the need to increase fin density in a single integrated system, thereby reducing manufacturing costs while maintaining heat dissipation capability.
Solution Approach 2:
The patent introduces an oil-water heat exchanger as an intermediary component that enables heat transfer between the oil-cooling circuit and water-cooling circuit. This intermediary allows flexible heat management without directly increasing fin density in the inverter's heat dissipation plate, thus avoiding increased hardware and process costs.
2Productivity
If the fin density of the oil-water heat exchanger is increased to improve heat dissipation capability, then the heat exchange efficiency is improved, but not only costs are increased, but a volume is also increased, and consequently, power-volume density of the powertrain is restricted
Solution Approach 1:
The patent segments the cooling functions by creating separate oil-cooling and water-cooling circuits with dedicated heat exchangers. This segmentation allows the oil-water heat exchanger to operate at optimal efficiency without needing excessive fin density, thereby controlling its volume and preserving powertrain power-volume density.
Solution Approach 2:
The patent changes the operating parameters of the heat exchanger by using separate oil and water cooling circuits with independent flow control. This allows the oil-water heat exchanger to achieve effective heat transfer with reduced fin density and smaller volume compared to a single high-density heat exchanger system.
3Productivity
If the fin density of the heat dissipation plate of the inverter and the fin density of the oil-water heat exchanger are increased to improve heat dissipation capability, then the heat dissipation efficiency is improved, but flow resistance of cooling water when circulating in the radiator of the inverter and the oil-water heat exchanger is significantly increased, and consequently, a coolant flow rate decreases at same output power of the water pump
Solution Approach 1:
The patent divides the cooling system into separate oil-cooling and water-cooling circuits, allowing each circuit to have optimized flow paths and resistance characteristics. This segmentation prevents the cumulative flow resistance that would occur in a single high-density fin system, maintaining coolant flow rate at the same pump output power.
Solution Approach 2:
The oil-water heat exchanger acts as an intermediary that decouples the flow resistance of the oil circuit from the water circuit. This allows the water pump to operate with lower flow resistance while still achieving effective heat dissipation through the heat exchanger, maintaining coolant flow rate without increasing pump power.
4Productivity
If the cooling flow is increased to improve heat dissipation capability of the inverter, then the heat dissipation efficiency is improved, but the power consumption of the water pump is increased
Solution Approach 1:
The patent segments the cooling load by assigning the inverter to the oil-cooling circuit and the motor to the water-cooling circuit. This allows the water pump to operate at lower flow rates and power consumption while still achieving effective heat dissipation for the motor, and the inverter is cooled independently through the oil circuit.
Solution Approach 2:
The oil-water heat exchanger serves as an intermediary that allows heat transfer between the two circuits without requiring the water pump to handle the full cooling load. This reduces the power consumption of the water pump while maintaining effective heat dissipation for both the inverter and motor.
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 enhances heat dissipation efficiency for the inverter and motor, reducing the risk of over-temperature and maintaining performance without the need for complex, high-cost heat dissipation designs, while minimizing flow resistance and costs.
Implementation Method 1
a heat exchanger, separately connected to the first cooling circuit and the second cooling circuit, and configured to perform heat exchange between the first cooling medium and the second cooling medium
Data Source
AI summary
A temperature control system includes: a first cooling circuit, where a first cooling medium is circulated in the first cooling circuit, and the first cooling circuit is configured to cool a first structural unit; a second cooling circuit, where a second cooling medium is circulated in the second cooling circuit, and the second cooling circuit is configured to cool a second structural unit; and a heat exchanger, separately connected to the first cooling circuit and the second cooling circuit, and configured to perform heat exchange between the first cooling medium and the second cooling medium, where the first cooling circuit includes a bypass branch, and the bypass branch is connected in parallel to the heat exchanger. According to the temperature control system, heat dissipation efficiency for an inverter and an overall heat dissipation capability for a powertrain are improved.