Vehicle HVAC Supercooling Control for Stable Cabin Air Temperature
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Solution Overview
Problem
Electric vehicle air conditioning systems face challenges in maintaining consistent interior temperatures and humidity due to variations in refrigerant temperature and heat release across radiators and outdoor heat exchangers, especially when the vehicle is in motion, leading to difficulties in controlling the temperature and humidity settings.
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, ensuring consistent refrigerant supercooling and condensing pressure, and includes a high-pressure refrigerant flow regulating valve to manage refrigerant flow between the radiator and outdoor heat exchanger, thereby controlling the temperature and humidity levels within the vehicle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the degree of supercooling of the refrigerant is increased to improve radiator radiation performance, then the heat release efficiency is improved, but the temperature difference between upstream and downstream of the radiator increases, making it difficult to control the air temperature
Solution Approach 1:
The patent dynamically adjusts the degree of supercooling of the refrigerant based on the target air temperature. When the target air temperature is high, a higher degree of supercooling is applied to improve heat release efficiency. When the target air temperature is low, a lower degree of supercooling is used to reduce temperature differences and improve temperature control precision. This parameter adjustment resolves the contradiction between heat release efficiency and temperature control precision.
2Loss of energy
If the amount of air supplied from the fan is reduced, then energy consumption is decreased, but the temperature difference in the air after heat exchange in the radiator increases
Solution Approach 1:
The patent compensates for reduced air flow by adjusting the degree of supercooling of the refrigerant. When the fan supplies less air, the system increases the degree of supercooling to enhance the heat release capacity of the refrigerant, thereby maintaining adequate temperature uniformity in the air after heat exchange without requiring high fan power consumption.
3Productivity
If the opening of the expansion valve is controlled to increase supercooling, then the heat release performance is improved, but the condensing pressure varies, affecting system stability
Solution Approach 1:
The patent employs feedback control by monitoring the condensing pressure and the degree of supercooling, and adjusting the expansion valve opening accordingly. The valve opening control part receives information about condensing pressure and supercooling degree, and dynamically adjusts the expansion valve to maintain both adequate heat release performance and stable condensing pressure, resolving the contradiction between these two parameters.
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 effectively reduces temperature variations within the vehicle, ensures consistent heat release, and maintains preset temperature and humidity settings by adjusting the supercooling and condensing pressure, preventing frost formation and ensuring efficient heat absorption even in low outdoor temperatures.
Implementation Method 1
a compressor configured to compress and discharge a refrigerant
Implementation Method 2
a radiator provided in a vehicle interior and configured to release 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.