Scroll Compressor Oil Flow Control for Back Pressure Chamber Temperature
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Solution Overview
Problem
In scroll compressors, fully closing the solenoid valve leads to oil stagnation in the back pressure chamber, causing temperature increases that can affect peripheral devices and reduce compressor efficiency.
Innovation Solution
A control method that adjusts the flow rate of oil through the oil drain passage based on the orbital speed of the scroll compressor, increasing the flow rate when the speed is below a threshold to prevent oil stagnation and reduce friction losses, and maintaining a higher flow rate when the speed is above a threshold to enhance heat exhaust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the solenoid valve is fully closed to increase oil amount in the back pressure chamber, then the anti-thrust force is increased and compressor efficiency is improved, but the oil temperature gradually increases and may influence peripheral devices
Solution Approach 1:
The solenoid valve opening degree is dynamically adjusted based on the compressor operating state. When the compressor operates at low capacity or in defrost mode, the valve is fully closed to maximize anti-thrust force and efficiency. When operating at high capacity or during normal cooling/heating, the valve is partially opened to control oil temperature, preventing overheating while maintaining adequate anti-thrust force.
Solution Approach 2:
The opening degree of the solenoid valve is changed as a control parameter to regulate oil flow rate through the back pressure chamber. By adjusting this parameter, the system can balance between maintaining oil amount for anti-thrust force and controlling oil temperature through increased flow and heat exchange, thus resolving the contradiction between efficiency and temperature control.
2Force
If the flow rate of oil through the oil drain passage is reduced to increase oil amount in the back pressure chamber, then the anti-thrust force is increased, but the heat exhaust performance deteriorates
Solution Approach 1:
The oil flow rate through the oil drain passage is dynamically controlled by adjusting the solenoid valve opening degree based on compressor operating conditions. This dynamic control allows the system to optimize the balance between maintaining sufficient oil amount for anti-thrust force and ensuring adequate heat exhaust performance by increasing flow rate when temperature becomes excessive.
Solution Approach 2:
The system uses feedback from compressor operating state (capacity mode, defrost mode, cooling/heating mode) to adjust the solenoid valve opening degree. This feedback mechanism ensures that the oil flow rate is optimized in real-time to maintain both adequate anti-thrust force and proper heat exhaust performance under varying operating conditions.
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 prevents excessive temperature increases in the back pressure chamber, reduces friction losses, and maintains compressor efficiency by optimizing oil flow and heat management.
Implementation Method 1
exhaust heat is not sufficiently performed, a temperature of the oil in the back pressure chamber gradually increases
Implementation Method 2
exhaust heat is not sufficiently performed
Data Source
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AI summary
The purpose of the present invention is to avoid the influence of an increase in oil temperature on peripheral devices while suppressing deterioration of the efficiency of a compressor. This scroll compressor is provided with a back pressure chamber, an oil discharge passage through which oil discharged from the back pressure chamber returns to an oil reservoir in a housing, a valve provided to the oil discharge passage, and a control device which controls the opening degree of the valve. When the compressor rotating speed R is lower than a first threshold Rth1, the control device controls the flow rate of oil flowing through the oil discharge passage to a preset first flow rate or lower, and temporarily increases the flow rate of oil flowing through the oil discharge passage at a prescribed timing. When the compressor rotating speed R is equal to or higher than a second threshold Rth2, the control device controls the flow rate of oil flowing through the oil discharge passage to at least a second flow rate which is a value greater than the first flow rate.