Vehicle AC Refrigerant Bypass Control for Dehumidifying Heating
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Solution Overview
Problem
Conventional vehicle air-conditioning apparatuses with dehumidifying heating functions experience reduced dehumidifying ability during intermediate thermal load times, where outside air temperatures range from 15 to 25°C, due to elevated evaporation pressures in the second heat exchanger, leading to insufficient heat absorption and dehumidification.
Innovation Solution
The apparatus incorporates a refrigerant control system with multiple throttling and bypass paths, allowing for adjustable refrigerant flow through the vehicle exterior heat exchanger and second heat exchanger, using first, second, third, and fourth refrigerant control parts to manage refrigerant flow and pressure, ensuring dehumidifying ability by throttling and bypassing refrigerant paths based on thermal load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vehicle air-conditioning apparatus uses a conventional refrigerant flow path configuration with limited control parts, then the device complexity is reduced, but the dehumidifying ability deteriorates during intermediate thermal load times due to elevated evaporation pressures
Solution Approach 1:
The refrigerant control system is segmented into multiple independent control parts (first, second, third, and fourth refrigerant control parts) that can independently regulate different segments of the refrigerant flow path. This segmentation allows precise control of refrigerant flow to the second heat exchanger, maintaining dehumidifying ability during intermediate thermal load times while managing system complexity through modular control architecture.
Solution Approach 2:
The refrigerant control parts are designed to dynamically adjust refrigerant flow based on thermal load conditions. The system transitions between different operational states by activating or deactivating specific control parts, enabling adaptive response to varying thermal demands while maintaining optimal dehumidifying performance across different operating conditions.
2Adaptability or versatility
If the refrigerant flow path is simplified with fewer control parts, then the ease of operation is improved, but the adaptability to varying thermal load conditions deteriorates
Solution Approach 1:
The refrigerant control parts are configured to automatically regulate refrigerant flow based on predefined operational criteria and thermal load conditions. The system performs self-adjustment through the coordinated action of multiple control parts, eliminating the need for manual intervention while adapting to varying thermal demands across different operating scenarios.
Solution Approach 2:
The multiple refrigerant control parts serve multiple functions within a unified system architecture. Each control part can independently manage different aspects of refrigerant flow, and their combined operation provides universal adaptability across various thermal load conditions, from low to intermediate thermal loads, while maintaining streamlined operation.
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 maintains dehumidifying and heating abilities across varying thermal loads, preventing evaporation pressure increases in the second heat exchanger and ensuring effective air conditioning by adjusting refrigerant flow and pressure, thus addressing the limitations of conventional systems.
Implementation Method 1
heat of the refrigerant compressed by the compressor 6 is radiated by the first heat exchanger 2
Implementation Method 2
some heat is absorbed by the refrigerant at the second heat exchanger 3
Implementation Method 3
a refrigerant compressed by the compressor 6
Implementation Method 4
a pressure of the refrigerant is reduced by the second expansion device 41
Data Source
Figure 1A~1B
Figure 2~3
Figure 4A~4B
AI summary
[Purpose] To provide a vehicle air-conditioning apparatus which can ensure a dehumidifying ability even during an intermediate thermal load time where an outside air temperature becomes high during a dehumidifying heating operation time. [Solution] In a vehicle air-conditioning apparatus, at least a compressor 6, a first heat exchanger 2, a first refrigerant control part 9 which is formed by connecting a first expansion device 7 and a first open/close valve 8 in parallel to each other, a vehicle exterior heat exchanger 4, a second refrigerant control part 13 which is formed by connecting a second expansion device 12 and a second open/close valve 11 in series, and a second heat exchanger 3 are connected in the preceding order in a loop. A refrigerant flow path between the first heat exchanger 2 and the first refrigerant control part 9 and a refrigerant flow path between the second refrigerant control part 13 and the second heat exchanger 3 are connected with each other by a first bypass flow path 21 provided with a third refrigerant control part 16 formed by connecting a third expansion device 15 and a third open/close valve 14 in series, and a refrigerant flow path between the vehicle exterior heat exchanger 4 and the second refrigerant control part 13 and a refrigerant flow path between the second heat exchanger 3 and the compressor 6 are connected with each other by a second bypass flow path 22 which is opened or closed by a fourth open/close valve 17.