Methods and systems for a vehicle air conditioning system
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Solution Overview
Problem
The performance of compressor suction valves in vehicle air conditioning systems is affected by refrigerant temperature and torque stability, leading to issues such as icing, airflow blockage, unpleasant odors, and increased noise vibration and harshness (NVH), which impact the system's efficiency and comfort.
Innovation Solution
A method is developed to determine and control the current through the compressor suction valve based on the speed of the evaporator fan, using relationships between suction valve current, air inlet temperature, and evaporator temperature to maintain a target evaporator temperature, thereby regulating the refrigerant temperature and system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the evaporator temperature is reduced to improve cooling efficiency, then the cooling performance increases, but icing occurs on the evaporator causing airflow blockage
Solution Approach 1:
The system uses feedback control by monitoring evaporator temperature and adjusting the suction valve current accordingly. When the evaporator temperature approaches the icing point, the controller increases the suction valve current to reduce refrigerant flow and prevent further temperature drop, thus avoiding icing while maintaining efficient cooling operation.
Solution Approach 2:
The system dynamically changes the suction valve current parameter based on evaporator temperature conditions. By adjusting this parameter in real-time, the refrigerant flow rate is controlled to maintain evaporator temperature within an optimal range that prevents icing while maximizing cooling efficiency.
2Object-affected harmful factors
If the evaporator temperature is increased to prevent icing, then airflow blockage is avoided, but unpleasant odors occur due to insufficient cooling
Solution Approach 1:
The feedback control system continuously monitors evaporator temperature and adjusts the suction valve current to maintain temperature within an optimal range. This prevents the temperature from rising too high, which would cause unpleasant odors, while also preventing it from dropping too low, which would cause icing and airflow blockage.
Solution Approach 2:
The system dynamically adjusts the suction valve current based on real-time evaporator temperature conditions, allowing the operating parameters to adapt to changing conditions. This dynamic control ensures the evaporator temperature remains within the optimal range that prevents both icing and odor generation.
3Productivity
If the suction valve current is increased to improve refrigerant flow, then cooling performance increases, but torque disturbances increase causing NVH
Solution Approach 1:
The system uses feedback control to adjust the suction valve current based on evaporator temperature and compressor operating conditions. By optimizing the current rather than simply increasing it, the system maintains efficient refrigerant flow while operating in a stable torque region that minimizes vibrations and noise.
Solution Approach 2:
The system optimizes the suction valve current parameter based on real-time operating conditions including evaporator temperature and compressor speed. This parameter optimization ensures efficient refrigerant flow is maintained while avoiding current values that would cause torque disturbances and associated NVH issues.
4Object-generated harmful factors
If the suction valve current is decreased to reduce torque disturbances, then NVH is reduced, but refrigerant flow decreases affecting cooling efficiency
Solution Approach 1:
The feedback control system monitors evaporator temperature and adjusts the suction valve current to maintain optimal cooling performance. When cooling demand is high, the current is increased to maintain efficient refrigerant flow, while when conditions are stable, the current is optimized to minimize torque disturbances and NVH, thus achieving both goals dynamically.
Solution Approach 2:
The system dynamically optimizes the suction valve current based on real-time operating conditions. Rather than using a fixed low current setting, the system adjusts the current dynamically to maintain efficient cooling when needed while operating in stable torque regions when possible, thus achieving both NVH reduction and cooling efficiency.
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 effectively mitigates evaporator icing, odor issues, and torque disturbances, improving the AC system's efficiency, comfort, and fuel economy by maintaining optimal refrigerant and evaporator temperatures.
Implementation Method 1
An evaporator fan blows air to be cooled over the evaporator coil
Implementation Method 2
As the air to be cooled flows over the evaporator coil(s) the cold liquid refrigerant flowing through the coil(s) removes heat from the air to cool the air
Implementation Method 3
in the evaporator the liquid refrigerant changes its state from liquid to vapor
Implementation Method 4
the cold liquid refrigerant is heated by the air to be cooled (as the heat is removed from the air by the refrigerant)
Implementation Method 5
compress refrigerant vapor into a high temperature, high pressure, refrigerant vapor
Implementation Method 6
In the condenser, the refrigerant vapor may be condensed to remove some of the heat from the hot gas via ambient air passing across at least one fin, or coil of the condenser
Implementation Method 7
the refrigerant vapor which is condensed into a liquid
Implementation Method 8
At the expander, the warm liquid refrigerant may undergo expansion causing a pressure drop. The pressure drop causes a temperature drop
Data Source
AI summary
Methods and systems are provided for an air conditioning system. An example method of determining current through a compressor suction valve in a vehicle air conditioning (AC) system is provided, the AC system comprises an evaporator fan and the method includes determining the speed of the evaporator fan and determining the current through the suction valve based on the speed of the evaporator fan.