Dynamic Evaporator Temperature Control for Vehicle HVAC
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Solution Overview
Problem
Current air conditioning systems in vehicles consume excessive energy and result in uncomfortable dry air at high outside temperatures, leading to increased fuel consumption and CO2 emissions when trying to maintain a comfortable interior temperature and humidity.
Innovation Solution
A method and control unit that regulate the evaporator temperature by initially setting it to a minimum at high outside temperatures, then increasing it to achieve a comfortable interior humidity range, reducing energy use and emissions, using sensors for real-time adjustments and optimizing fresh air intake.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the evaporator temperature is controlled to a minimum value near the freezing point to achieve fast cooling at high outside air temperatures, then the cooling speed is improved, but the relative humidity in the passenger compartment becomes too low and the air becomes uncomfortably dry
Solution Approach 1:
The evaporator temperature control is made dynamic by switching between two operating modes based on the cooling state of the passenger compartment. Initially, the evaporator temperature is controlled to a minimum value for fast cooling, then switched to a higher temperature for maintaining comfort and humidity, resolving the contradiction between cooling speed and passenger comfort
Solution Approach 2:
The air conditioning system operates in periodic cycles, alternating between a first operating mode with minimum evaporator temperature for rapid cooling and a second operating mode with higher evaporator temperature for maintaining comfortable humidity levels, thus resolving the contradiction between fast cooling and comfort
2Quantity of substance
If the evaporator temperature is decreased to a minimum allowable temperature to dehumidify the air, then the dehumidifying effect is improved, but the energy consumption increases due to the need to reheat the air
Solution Approach 1:
The system dynamically adjusts the evaporator temperature based on the required humidity control. By switching to the second operating mode with higher evaporator temperature after initial cooling, the system maintains dehumidification效果 while avoiding excessive energy consumption from continuous low-temperature operation and subsequent reheating
Solution Approach 2:
The air conditioning system uses periodic operation between two modes: first mode with minimum evaporator temperature for rapid dehumidification, and second mode with higher evaporator temperature for maintaining humidity with lower energy consumption, thus resolving the contradiction between dehumidification effect and energy consumption
3Power
If the evaporator temperature is controlled to a minimum value to achieve adequate cooling, then the cooling capacity is improved, but the fuel consumption increases
Solution Approach 1:
The evaporator temperature control is dynamically adjusted based on the cooling demand. The system initially uses minimum evaporator temperature for rapid cooling when needed, then switches to higher temperature operation to maintain cooling capacity with reduced fuel consumption, resolving the contradiction between cooling capacity and fuel consumption
Solution Approach 2:
The system operates periodically in two modes: first mode with minimum evaporator temperature for rapid cooling and higher fuel consumption, and second mode with higher evaporator temperature for maintaining cooling with lower fuel consumption, thus resolving the contradiction between cooling capacity and fuel consumption
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 approach reduces fuel consumption and CO2 emissions by maintaining a comfortable interior humidity, while minimizing energy usage and avoiding the need for excessive cooling, thereby enhancing passenger comfort and system efficiency.
Implementation Method 1
the evaporator temperature is controlled or regulated to a predetermined minimum evaporator temperature in the vicinity of the freezing point
Implementation Method 2
the air, guided over the evaporator, is not decreased to the potential minimum value. Rather, an evaporator temperature that is higher as a function of the outside air temperature is selected
Data Source
AI summary
A method and apparatus controls and/or regulates the evaporator temperature of an air conditioning system in a motor vehicle in cooling mode. When an outside air temperature exceeds a predetermined limit value, the evaporator temperature is controlled and/or regulated to a predetermined minimum evaporator temperature until a predetermined desired temperature in the interior of the vehicle is reached. After reaching the predetermined desired temperature in the interior of the vehicle, the evaporator temperature is increased until a predetermined interior humidity in the vehicle is reached, or the interior temperature is higher than the predetermined desired temperature for the interior of the vehicle.