Compressor Oil Return Valve Control for Low-Loss Lubrication
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Solution Overview
Problem
Existing systems for monitoring and controlling lubricating oil return to a compressor in central air conditioning systems are inefficient, leading to low oil levels, high energy waste, and potential compressor damage, as they rely on either full open or full closed valve configurations, which result in significant power loss and inefficient operation.
Innovation Solution
A system that uses a pressure sensor at the compressor outlet, an oil level sensor, and a temperature sensor in the oil box to control the valve opening of the oil return valve through a proportional-integral-derivative (PID) controller or segmentation principle, ensuring optimal oil return by continuously monitoring and adjusting the valve opening based on oil level, temperature, and pressure parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the oil return valve is left open to full (100% opening) to drive lubricating oil back to the oil box, then the oil return is ensured, but the system wastes a lot of electric energy and reduces system efficiency
Solution Approach 1:
The patent applies dynamic control by replacing the static full-open valve configuration with a dynamically adjustable valve opening mechanism. The valve opening degree is continuously adjusted based on real-time feedback from oil level sensors and pressure sensors, allowing the system to maintain reliable oil return while minimizing energy consumption by opening the valve only as much as necessary.
Solution Approach 2:
The patent changes the control parameter from a fixed binary state (fully open or fully closed) to a continuous variable parameter (valve opening degree). By controlling the valve opening degree as a variable parameter based on oil level and pressure conditions, the system achieves both reliable oil return and reduced energy waste through precise parameter optimization.
2Reliability
If the oil return valve is controlled with ON-OFF control (0% or 100% opening) based on oil level detection, then the oil level can be maintained, but the valve opening switches cause great increment or decrement leading to energy waste and efficiency deterioration
Solution Approach 1:
The patent transitions from static ON-OFF control to dynamic proportional control. Instead of abruptly switching the valve between 0% and 100% opening, the system dynamically adjusts the valve opening degree to any position within the full range, enabling smooth transitions that maintain oil level while avoiding the energy waste associated with frequent full-opening-closing cycles.
Solution Approach 2:
The patent applies partial action by opening the valve only to the extent necessary to maintain proper oil level, rather than using full-opening control. This partial opening approach reduces the excessive action of full valve cycling, thereby minimizing energy waste while still achieving the goal of maintaining adequate oil levels in the compressor.
3Loss of energy
If continuous monitoring and proportional control of valve opening is implemented, then energy efficiency is improved, but the system complexity increases with additional sensors and control mechanisms
Solution Approach 1:
The patent implements feedback control by incorporating oil level sensors and pressure sensors that continuously monitor system conditions and feed this information back to the control mechanism. This feedback enables automatic adjustment of the valve opening degree, achieving energy efficiency through proportional control while the automated feedback loop manages the complexity by eliminating the need for manual intervention.
Solution Approach 2:
The system applies self-service through automatic control where the sensors and control mechanism work together to autonomously regulate the valve opening based on real-time oil level and pressure conditions. This self-regulating capability reduces the need for external monitoring and manual adjustment, offsetting the increased device complexity with automated operation that simplifies overall system management.
4Ease of operation
If the compressor operates with low oil level to reduce monitoring frequency, then operational simplicity is maintained, but friction increases causing damage to bearings and the compressor
Solution Approach 1:
The patent uses feedback from oil level sensors to automatically adjust valve opening in real-time, ensuring adequate oil levels are maintained without requiring manual monitoring or intervention. This continuous feedback control protects the compressor from low oil level damage while maintaining operational simplicity through automation.
Solution Approach 2:
The system applies self-service by automatically monitoring and regulating oil levels through integrated sensors and control mechanisms. The system self-regulates to maintain protective oil levels without external intervention, thereby protecting the compressor while keeping the operation simple and automated.
Data Source
AI summary
A system and method for monitoring and controlling oil return to a compressor, characterized by monitoring and controlling oil level, oil temperature, and compressor outlet pressure, so as to determine whether the oil level is lower than a predetermined level threshold, whether the temperature in the lubricating oil box is lower than a predetermined temperature threshold, and whether the compressor outlet pressure exceeds a predetermined pressure threshold, so as to control the flow of lubricating oil returned to the oil box by controlling the valve opening of the oil return valve according to a non-segmentation principle or a segmentation principle, ensure sufficient lubricating oil in the oil box, and enhance efficiency of the system.