Vehicle Thermal Management With Refrigerant Subcooling Control
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Solution Overview
Problem
Traditional thermal management systems in vehicles with thermal combustion engines face inefficiencies in collecting, storing, and distributing thermal energy, particularly in innovative propulsion systems like battery electric vehicles, hybrid electric vehicles, or fuel cell vehicles, where available excess thermal energy is significantly lower.
Innovation Solution
A thermal management system comprising multiple fluid flow circuits, including a HVAC circuit and a propulsion cooling circuit, where a heat exchanger facilitates thermal energy exchange between refrigerant and coolant to achieve subcooling, with a controller adjusting control points to achieve target subcooling, temperature, and flow rates, and optionally includes a drive unit cooling circuit for additional thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional thermal management systems are used in vehicles with thermal combustion engines, then thermal energy management is established, but the system efficiency deteriorates in innovative propulsion systems like BEVs, HEVs, or fuel cell vehicles where available excess thermal energy is much lower
Solution Approach 1:
The thermal management system is designed to serve multiple functions across different propulsion systems. The HVAC system integrates with the propulsion cooling circuit to provide both cabin conditioning and propulsion component cooling, allowing the same system to adapt to BEVs, HEVs, fuel cell vehicles, and traditional combustion engine vehicles with varying thermal energy availability
Solution Approach 2:
The patent combines the HVAC refrigerant circuit with the propulsion cooling circuit through heat exchangers. The refrigerant loop is merged with coolant loops to enable thermal energy sharing, where the HVAC system can utilize waste heat from propulsion components or draw cooling capacity during high thermal loads, improving overall system efficiency in low-excess-thermal-energy vehicles
2Reliability
If subcooling is increased to improve refrigerant performance, then expansion valve performance improves, but system complexity increases due to additional control points
Solution Approach 1:
The controller monitors refrigerant conditions and adjusts control points (such as expansion valve positions or heat exchanger operation) to maintain optimal subcooling levels. This feedback mechanism ensures reliable expansion valve operation by preventing refrigerant flash gas formation while avoiding excessive system complexity through automated control
Solution Approach 2:
The thermal management system uses its own thermal energy resources to achieve subcooling. The refrigerant circuit utilizes heat exchangers with the propulsion cooling circuit, where available thermal energy from propulsion components provides the subcooling function internally, eliminating the need for separate external subcooling devices and reducing overall system 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
This system efficiently manages thermal energy across vehicle systems, ensuring optimal subcooling and temperature control, enhancing the performance and efficiency of propulsion and drive unit components in vehicles with limited excess thermal energy.
Implementation Method 1
The flow of coolant is directed through the heat exchanger to exchange thermal energy with the flow of refrigerant, thus subcooling the flow of refrigerant
Data Source
AI summary
A thermal management system for a vehicle includes a plurality of fluid flow circuits including a heating ventilation and air conditioning (HVAC) circuit circulating a flow of refrigerant therethrough and including an evaporator, a chiller heat exchanger, a first expansion valve located upstream of the evaporator, a second expansion valve located upstream of the chiller heat exchanger, and a heat exchanger located fluidly upstream of the expansion valves. A propulsion cooling circuit circulates a flow of coolant therethrough which is utilized to condition one or more propulsion components of the vehicle. The flow of coolant is directed through the heat exchanger, thus subcooling the flow of refrigerant. A controller is operably connected to one or more control points of the thermal management system and is configured to adjust the one or more control points to achieve a target amount of subcooling of the flow of refrigerant at the heat exchanger.