Vehicle Air-Conditioning Injection Circuit for Stable Heating
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Solution Overview
Problem
The existing vehicle air-conditioning devices face limitations in achieving sufficient heating qualification due to low refrigerant flow rates and frost formation in outdoor heat exchangers, which leads to reduced heating performance and increased power consumption during defrost operations.
Innovation Solution
The implementation of a vehicle air-conditioning device with an injection circuit that includes pressure reducing means and a water circulation circuit, allowing for gas injection to the compressor and heat exchange between decompressed refrigerant and water, which enhances refrigerant flow rates and suppresses frost formation by controlling refrigerant flow and using heated water for additional heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If refrigerant is distributed and decompressed in the injection circuit, then the amount of refrigerant to be discharged from the compressor is increased, but the heat exchange amount between the refrigerant and decompressed refrigerant becomes smaller due to low temperature of refrigerant flowing out from the radiator
Solution Approach 1:
A heat exchanger is introduced as an intermediary component between the radiator outlet and the injection circuit. The heat exchanger transfers heat from the refrigerant flowing out of the radiator to the decompressed refrigerant before it enters the compressor, thereby increasing the heat exchange amount and improving the temperature of the refrigerant being compressed
2Reliability
If defrost operation is executed to remove frost from the outdoor heat exchanger, then frost formation is removed, but the temperature of air blown out into the vehicle interior lowers and power consumption increases
Solution Approach 1:
A control system continuously monitors the operation state of the air-conditioning device and adjusts the injection circuit operation accordingly. When the outdoor heat exchanger is operating as an evaporator during heating mode, the control system activates the injection circuit to prevent frost formation. The control system receives feedback about system conditions and dynamically controls the injection valve to maintain optimal operation without unnecessary defrost cycles
3Reliability
If defrost operation is executed to remove frost from the outdoor heat exchanger, then frost formation is removed, but comfort is impaired due to lower air temperature blown into the vehicle interior
Solution Approach 1:
The injection circuit performs preliminary action by preventing frost formation on the outdoor heat exchanger before it significantly impacts performance. By controlling the injection of decompressed refrigerant during heating mode when the outdoor heat exchanger is acting as an evaporator, frost is prevented from forming in the first place, eliminating the need for defrost operations that would compromise comfort
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 solution improves heating qualification by increasing refrigerant flow rates and reduces frost formation, maintaining comfort and efficiency while minimizing power consumption during heating operations.
Implementation Method 1
distributes a part of the refrigerant flowing out from the radiator, decompresses this distributed refrigerant
Implementation Method 2
a discharge side heat exchanger which performs heat exchange between the refrigerant decompressed by this pressure reducing means and the refrigerant discharged from the compressor
Implementation Method 3
a compressor which compresses a refrigerant
Implementation Method 4
a radiator disposed on a vehicle interior side to let the refrigerant radiate heat
Implementation Method 5
an outdoor heat exchanger disposed outside the vehicle interior to let the refrigerant radiate or absorb heat
Data Source
AI summary
There is disclosed a vehicle air-conditioning device in which a heating qualification by gas injection can sufficiently be obtained. The vehicle air-conditioning device comprises a compressor 2 which compresses a refrigerant, an air flow passage 3 through which air to be supplied into a vehicle interior flows, a radiator 4 disposed in the air flow passage to let the refrigerant radiate heat, a heat absorber 9 disposed in the air flow passage to let the refrigerant absorb heat, an outdoor heat exchanger 7 disposed outside the vehicle interior to let the refrigerant radiate or absorb heat, and a controller. The controller executes a heating mode in which the refrigerant discharged from the compressor 2 radiates heat in the radiator 4 and the refrigerant by which heat has been radiated is decompressed and then absorbs heat in the outdoor heat exchanger 7. The vehicle air-conditioning device comprises an injection circuit 40 which distributes a part of the refrigerant flowing out from the radiator 4 to return the refrigerant to the middle of compression by the compressor 2, and the injection circuit 40 has an expansion valve 30, and a discharge side heat exchanger 35 which performs heat exchange between the refrigerant decompressed by the expansion valve 30 and the refrigerant discharged from the compressor 2 before flowing into the radiator 4.