Vehicular Refrigeration Cycle Flow Switching for Low-Temperature Heating
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Solution Overview
Problem
Existing vehicular refrigeration cycle units face challenges in precisely controlling the temperature of secondary refrigerants, particularly when outside air temperatures are very low, leading to insufficient pressure and flow rate of primary refrigerants.
Innovation Solution
A vehicular refrigeration cycle unit is introduced, featuring a refrigeration cycle with a compressor, condenser, expansion valve, and evaporator, along with flow passage switching valves and flow rate adjustment units, allowing for precise control of secondary refrigerant flow rates between the vehicle exterior and interior heat exchangers, enabling better temperature adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the secondary refrigerant simply flows while being mixed at the evaporator side, then the pressure of the primary refrigerant heading to the compressor can be increased, but it is difficult to precisely control the temperature of the secondary refrigerant
Solution Approach 1:
The patent segments the flow control by introducing separate flow passage switching valves (60) for the secondary refrigerant circuit and flow rate adjustment units (42, 52) that independently control flow rates in different passages. This allows precise temperature control of the secondary refrigerant while maintaining the pressure increase effect in the primary refrigerant circuit.
Solution Approach 2:
The patent implements dynamic flow control using flow passage switching valves that can change the flow paths of the secondary refrigerant between the exterior and interior heat exchangers. This dynamic switching capability enables precise temperature adjustment of the secondary refrigerant by adapting the flow distribution to different operating conditions, while the mixed flow at the evaporator side continues to increase primary refrigerant pressure.
2Adaptability or versatility
If heat is absorbed from outside air under very low outside air temperature conditions, then the heat pump system can operate, but sufficient pressure of the primary refrigerant cannot be obtained and the compressor cannot generate sufficient flow rate
Solution Approach 1:
The patent merges two functions in the evaporator side: the heat absorption function from outside air and the refrigerant mixing function. By allowing the secondary refrigerant to flow through the evaporator and mix with the primary refrigerant, the system simultaneously absorbs heat from very cold outside air and increases the pressure of the primary refrigerant heading to the compressor, enabling operation under extreme low temperature conditions.
Solution Approach 2:
The secondary refrigerant acts as an intermediary substance that facilitates both heat absorption from the outside air and pressure increase of the primary refrigerant. The flow passage switching valves and flow rate adjustment units control the secondary refrigerant flow as a mediator to achieve the desired effects on the primary refrigerant system under low temperature conditions.
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 allows for more precise temperature control of secondary refrigerants, enhancing heating performance by increasing the pressure and density of primary refrigerants, thus improving the compressor's load and heating capacity, even at low outside air temperatures.
Implementation Method 1
a refrigeration cycle including a compressor 32, a condenser 33, an expansion valve 34, and an evaporator 35 through which a primary refrigerant sequentially flows
Implementation Method 2
an evaporator 35 through which a primary refrigerant sequentially flows
Implementation Method 3
a first flow rate adjustment unit 42 adjusting a flow rate of the secondary refrigerant flowing into the first bypass flow passage 41 and the evaporator 35
Implementation Method 4
a compressor 32, a condenser 33, an expansion valve 34, and an evaporator 35 through which a primary refrigerant sequentially flows
Implementation Method 5
a vehicle exterior heat exchanger 10 through which the secondary refrigerant flows
Implementation Method 6
a vehicle interior heat exchanger 20 through which the secondary refrigerant flows
Data Source
AI summary
A vehicular refrigeration cycle unit is a vehicular refrigeration cycle unit installed between a vehicle exterior heat exchanger and a vehicle interior heat exchanger and exchanging heat between secondary refrigerants respectively flowing through the vehicle exterior heat exchanger and the vehicle interior heat exchanger, the vehicular refrigeration cycle unit including: a refrigeration cycle including a compressor, a condenser, an expansion valve, and an evaporator through which a primary refrigerant sequentially flows; an exterior flow passage through which the secondary refrigerant is circulated between the evaporator and the vehicle exterior heat exchanger; an interior flow passage through which the secondary refrigerant is circulated between the condenser and the vehicle interior heat exchanger; a pair of flow passage switching valves connecting the exterior flow passage and the interior flow passage to allow to switch the flow state of the second refrigerant between the exterior flow passage and the interior flow passage; a first bypass flow passage which is installed aside the exterior flow passage and with bypassing the evaporator; and a first flow rate adjustment unit adjusting a flow rate of the secondary refrigerant flowing into the evaporator.