Vehicle Air Conditioning Supercooling Control for Stable Cabin Heating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electric vehicle air conditioning systems face challenges in maintaining consistent temperature and humidity control due to variations in refrigerant flow and heat exchange efficiency, particularly during heating and dehumidifying operations, especially when the outdoor temperature is low, leading to potential frost formation and reduced heating capacity.
Innovation Solution
The system incorporates a compressor, radiator, heat exchanger, and outdoor heat exchanger, with a target supercooling setting and valve control to regulate the expansion valve's opening based on air flow rates and refrigerant flow, and a high-pressure refrigerant flow regulating valve to manage condensing pressure, ensuring consistent heat release and absorption across both heat exchangers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the degree of supercooling of the refrigerant is increased to improve radiator radiation performance, then the heating capacity is improved, but the temperature difference between upstream and downstream refrigerant increases causing air temperature variation
Solution Approach 1:
The patent dynamically adjusts the degree of supercooling parameter based on operating conditions. When the indoor fan operates at low speed, the control unit reduces the degree of supercooling to maintain temperature uniformity. When the fan operates at high speed, the degree of supercooling is increased to maximize heating capacity. This parameter adjustment resolves the contradiction between heating performance and temperature uniformity.
2Productivity
If the opening of the expansion valve is increased to improve heat absorption in the heat exchanger, then the cooling performance is improved, but the refrigerant flow becomes unstable causing control precision degradation
Solution Approach 1:
The control unit continuously monitors the actual refrigerant flow and temperature conditions, then adjusts the expansion valve opening to maintain optimal performance. The feedback mechanism ensures that when cooling performance needs improvement, the valve opening is increased appropriately without causing instability, thereby maintaining both productivity and control precision.
3Productivity
If the refrigerant flow rate is increased to enhance heat exchange efficiency, then the heating and dehumidifying performance is improved, but the pressure fluctuations increase causing system reliability reduction
Solution Approach 1:
The system dynamically adjusts refrigerant flow rate based on real-time operating conditions including outdoor temperature, indoor humidity, and fan speed. By making the refrigerant flow adaptive rather than fixed, the system can enhance heating and dehumidifying performance when conditions permit, while maintaining stability when pressure fluctuations become problematic, thus resolving the contradiction between productivity and reliability.
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 reduces temperature variations within the vehicle, maintains preset interior temperatures, and prevents frost formation by securing the required heat absorption in the heat exchanger, even at low outdoor temperatures, thus ensuring reliable heating and dehumidification performance.
Implementation Method 1
a compressor configured to compress and discharge a refrigerant
Implementation Method 2
a radiator provided in the vehicle interior and configured to release the heat from the refrigerant
Implementation Method 3
a heat exchanger provided in the vehicle interior and configured to absorb the heat into the refrigerant
Implementation Method 4
an outdoor heat exchanger provided outside the vehicle interior and configured to release the heat from or absorb the heat into the refrigerant
Implementation Method 5
to decompress the refrigerant by an expansion valve
Data Source
AI summary
A vehicle air conditioning apparatus is provided that can prevent temperature variations of the air after the heat exchange in a radiator to reliably control the temperature of the air supplied to the vehicle interior. During the heating operation and the heating and dehumidifying operation, target degree of supercooling SCt when target air-blowing temperature TAO is a predetermined temperature or higher is set to SCt1 that is greater than SCt2 when the target air-blowing temperature TAO is lower than the predetermined temperature. When amount of air Ga supplied from indoor fan 12 is lower than a predetermined value, the target degree of supercooling SCt is corrected, which is set such that the degree of supercooling is lower than target degree of supercooling corrected when the amount of air Ga supplied from the indoor fan 12 is a predetermined value or higher.