Method for controlling vehicle air-conditioning system, and vehicle air-conditioning system
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Solution Overview
Problem
Conventional vehicle air-conditioning systems cannot effectively manage faults in electronic expansion valves, leading to potential damage when the valves stall or fail to operate, as they lack adequate countermeasures to maintain system performance.
Innovation Solution
A control method that determines the fault state of the electronic expansion valve based on its opening degree, actual superheat degree, and preset superheat degree, and outputs a control signal to adjust parameters like compressor speed or evaporator fan rotation to maintain system performance or shut down the system to prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the electronic expansion valve is used to control superheat degree, then the refrigeration efficiency is improved and temperature stability is enhanced, but the system becomes vulnerable to valve faults that can cause damage
Solution Approach 1:
The control system performs preliminary fault detection by monitoring the relationship between electronic expansion valve opening degree and actual superheat degree before faults can cause damage. When abnormality is detected (opening degree reaches limit but superheat degree is still outside preset range), the system proactively adjusts compressor speed or evaporator fan rotation to compensate, preventing catastrophic failure.
Solution Approach 2:
When the electronic expansion valve is detected to be in fault state, the system changes operating parameters of other components to maintain superheat degree control. Specifically, compressor speed is adjusted or evaporator fan rotation is modified to compensate for the valve's inability to properly regulate opening degree, thereby maintaining system reliability.
2Ease of operation
If the electronic expansion valve gets stuck or cannot open to required interval, then the valve fails to regulate superheat degree, but the conventional system lacks countermeasures leading to system damage
Solution Approach 1:
The system continuously monitors the actual superheat degree and compares it with the preset range while tracking the electronic expansion valve opening degree. When feedback shows that the valve opening degree has reached the limit (minimum or maximum) but the superheat degree remains outside the preset range, the system identifies this as a fault state and activates compensatory control measures.
Solution Approach 2:
The control system takes preliminary protective action by detecting the fault state before system damage occurs. When the valve gets stuck or cannot open to the required interval, the system proactively adjusts compressor speed or evaporator fan rotation to maintain proper superheat degree, preventing the harmful effects of uncontrolled refrigerant flow.
Data Source
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AI summary
Disclosed are a method for controlling a vehicle air-conditioning system, and a vehicle air-conditioning system. The method comprises: acquiring an actual degree of superheat, a preset degree of superheat and a degree of opening of an electronic expansion valve; and according to the actual degree of superheat, the preset degree of superheat and the degree of opening of the electronic expansion valve, judging whether the electronic expansion valve is in a fault state or not; if yes, outputting a control signal to an executive control mechanism to enable same to adjust a parameter of a device in a vehicle air-conditioning system which influences the variation of the actual degree of superheat, so as to adjust the degree of superheat of the vehicle air-conditioning system.