Dual-Circuit Powertrain Cooling With Inverter Bypass Flow Control
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Solution Overview
Problem
The challenge of efficiently dissipating heat in a miniaturized electric vehicle powertrain, particularly the inverter and motor, is exacerbated by increased heat consumption density, leading to over-temperature risks and high costs with conventional heat dissipation methods.
Innovation Solution
A temperature control system with a first and second cooling circuit and a heat exchanger, featuring a bypass branch and a controllable valve to optimize flow distribution, allowing for increased water flow in the water-cooling circuit to enhance heat dissipation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the fin density of the heat dissipation plate of the inverter is increased, then the heat dissipation capability of the inverter is improved, but the flow resistance of cooling water is significantly increased and hardware costs are high
Solution Approach 1:
The cooling system is segmented into multiple independent circuits (water-cooling circuit for inverter, oil-cooling circuit for motor, and oil-water heat exchanger). This segmentation allows each circuit to be optimized independently, enabling the inverter cooling to use a bypass branch that reduces flow resistance while the motor cooling uses high fin density heat exchanger, thus resolving the contradiction between heat dissipation capability and flow resistance.
2Temperature
If the fin density of the oil-water heat exchanger is increased, then the heat dissipation capability of the motor is improved, but the volume is increased and power-volume density is restricted
Solution Approach 1:
The patent extracts the heat dissipation function for the inverter from the oil-water heat exchanger by introducing a separate water-cooling circuit with a bypass branch. This allows the oil-water heat exchanger to focus solely on cooling the motor, enabling it to maintain compact volume while achieving effective heat dissipation through the dedicated oil-cooling circuit with optimized fin density.
3Temperature
If the cooling flow rate is increased, then the heat dissipation capability is improved, but the power consumption of the water pump is increased
Solution Approach 1:
The bypass branch is designed with a controllable valve that dynamically adjusts the flow distribution between the heat exchanger and the bypass based on real-time cooling demands. When the inverter requires intensive cooling, the valve opens to increase flow rate through the bypass, improving heat dissipation capability while avoiding the need for continuously high pump power consumption.
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 improves heat dissipation efficiency by reducing flow resistance and increasing water flow rate, effectively managing heat dissipation for the inverter and motor without complex, high-cost designs, reducing the risk of over-temperature.
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
Figure 1
Figure 2(a)~2(f)
Figure 3~4
AI summary
A temperature control system includes: a first cooling circuit (14), 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 (11); a second cooling circuit (15), 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 (12 and 13); and a heat exchanger (16), 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 (141), 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.