Joint Active Thermal Management with Refrigerant Storage
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Solution Overview
Problem
Current active thermal management systems in electric-drive vehicles are inefficient due to multiple independently operated thermal management subsystems, which require redundant components and are not optimized for extreme thermal fluctuations or ambient temperature variations.
Innovation Solution
A joint active thermal management system with mutually parallel thermal loops that store excess refrigerant in a heat exchanger device, allowing for dynamic thermal load management through electronic valves and control logic, enabling efficient cooling and heating of the vehicle's powertrain and passenger compartment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple independent thermal management subsystems are used to cool discrete powertrain components, then each component can be cooled independently, but the system requires redundant components and becomes inherently inefficient
Solution Approach 1:
The patent merges multiple independent thermal management subsystems into a single integrated system that uses one refrigerant compression cycle to serve multiple thermal zones (engine bay, cabin, battery). This consolidation eliminates redundant compressors, condensers, and expansion devices while maintaining the ability to independently control cooling in each zone through electronic expansion valves and zone controllers.
Solution Approach 2:
The integrated thermal management system performs multiple functions simultaneously: cooling the engine bay, cooling the cabin, and cooling the battery pack, all through a single refrigerant circulation system. The system can dynamically allocate refrigerant flow to different zones based on thermal demands, making the system universal rather than dedicated to single functions.
2Power
If the refrigerant system is designed for propulsion cooling loads in electric vehicles, then cooling capacity is increased, but the volume of active refrigerant required increases significantly
Solution Approach 1:
The system uses electronic expansion valves to dynamically control refrigerant flow distribution to different thermal zones based on real-time cooling demands. This dynamic allocation allows the system to maintain high cooling capacity when needed while minimizing the volume of active refrigerant circulating through the system at any given moment, as refrigerant is directed only to zones requiring cooling.
Solution Approach 2:
The system incorporates a refrigerant storage tank that acts as a buffer, allowing excess refrigerant to be stored when not immediately needed for cooling. This enables the system to have large total refrigerant volume available for high-demand cooling scenarios while maintaining smaller active refrigerant volumes during normal operation, effectively discarding and recovering refrigerant as needed.
3Quantity of substance
If a dedicated refrigerant storage tank is used to manage refrigerant levels, then refrigerant quantity control is achieved, but system hardware complexity and cost increase
Solution Approach 1:
The system uses existing thermal management components (heat exchangers, expansion valves, and the refrigerant circulation infrastructure) to perform refrigerant storage and level management functions. Rather than adding a dedicated storage tank, the system leverages the multi-functionality of existing components to control refrigerant distribution, thereby avoiding additional hardware complexity while achieving precise refrigerant quantity management.
4Adaptability or versatility
If extreme fluctuations in thermal loads are accommodated, then system adaptability is improved, but refrigerant level management becomes more challenging
Solution Approach 1:
The refrigerant storage tank serves as a buffer that absorbs refrigerant during high-demand cooling periods and releases it during low-demand periods. This discarding and recovering mechanism allows the system to accommodate extreme thermal load fluctuations while maintaining stable refrigerant levels in the active circulation portions of the system, preventing both overcharge and undercharge conditions.
Solution Approach 2:
The system incorporates sensors and controllers that continuously monitor thermal demands in different zones and refrigerant levels, providing feedback to the electronic expansion valves and compressor control. This feedback mechanism enables the system to dynamically adjust refrigerant flow to maintain stable levels while adapting to extreme thermal fluctuations in real-time.
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 approach allows for efficient thermal management across a wide range of ambient temperatures and driving modes, reduces hardware costs, and enhances the robustness of the thermal system by dynamically controlling refrigerant levels, thus protecting vehicle components and maintaining cabin comfort.
Implementation Method 1
the JATM system stores excess refrigerant in a heat exchanger device that is not active during heating modes of operation. For instance, a front-end condenser in parallel fluid-flow communication with the vehicle's heating, ventilation and air conditioning (HVAC) system, is selectively employed as a refrigerant storage sump for dynamically stowing surplus refrigerant
Implementation Method 2
a front-end condenser in parallel fluid-flow communication with the vehicle's heating, ventilation and air conditioning (HVAC) system, is selectively employed as a refrigerant storage sump
Data Source
AI summary
Presented are joint active thermal management (JATM) systems with heat exchanger storage of surplus refrigerant, methods for making/operating such systems, and vehicles equipped with such systems. A JATM system includes a coolant loop that fluidly connects to a vehicle battery system for pumping thereto coolant, an oil loop thermally coupled to the coolant loop and fluidly connected to a vehicle powertrain system for pumping thereto oil, and a refrigerant loop thermally coupled to the coolant loop and operable to circulate refrigerant for heating/cooling a passenger compartment. An electronic controller determines if a current amount of refrigerant in the refrigerant loop exceeds a calibrated threshold for the current operating mode of the JATM system. If so, the controller determines if one of the refrigerant loop's heat exchangers is available to store excess refrigerant. If the heat exchanger is available, the refrigerant loop stores excess refrigerant in the available refrigerant heat exchanger.