Variable Displacement Compressor Pressure Relief Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In variable displacement compressors, refrigerant pressure in the crank chamber is not sufficiently increased during minimum discharge displacement operations, leading to insufficient lubrication and reduced operational efficiency due to direct refrigerant leakage into the suction chamber through a pressure relief passage without passing through the crank chamber.
Innovation Solution
Incorporating an opening and closing mechanism for the pressure relief passage to control refrigerant pressure between the first control valve and the check valve, ensuring that most of the compressed refrigerant is supplied to the crank chamber, thereby increasing pressure and maintaining lubrication levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the pressure relief passage allows direct refrigerant flow to suction chamber, then refrigerant pressure relief is achieved, but lubricating oil flow to crank chamber is reduced
Solution Approach 1:
The pressure relief passage is dynamically opened or closed based on operational conditions. During minimum discharge displacement operation, the passage remains closed to ensure lubricating oil is supplied to the crank chamber. During normal operation with excessive pressure, the passage opens to relieve pressure, thus adaptively managing both pressure relief and lubrication requirements.
2Power
If the first control valve opens fully to minimize discharge displacement, then the compressor load is reduced, but the crank chamber pressure insufficiently increases
Solution Approach 1:
The pressure relief function is extracted from the main control valve system and implemented as a separate, independently controlled pressure relief passage with its own opening and closing means. This allows the first control valve to focus on discharge displacement control while the pressure relief passage independently manages crank chamber pressure, resolving the conflict between minimizing load and maintaining pressure.
Solution Approach 2:
The pressure relief passage acts as an intermediary mechanism between the pressure supply passage and suction chamber. It provides a controlled pathway for pressure relief that does not interfere with the primary function of the first control valve in regulating discharge displacement, enabling independent optimization of both functions.
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 solution effectively increases crank chamber pressure during minimum discharge displacement, reduces compressor load, and enhances operational efficiency by preventing refrigerant leakage and ensuring sufficient lubrication.
Implementation Method 1
a first control valve that controls an opening degree of a pressure supply passage that causes a discharge chamber and a crank chamber to communicate with each other
Implementation Method 2
a check valve that is interposed in the pressure supply passage downstream of the first control valve, and blocks a flow of a refrigerant from the crank chamber side to the first control valve side
Implementation Method 3
a second control valve that controls an opening degree of a pressure release passage that releases a refrigerant pressure in the crank chamber to a suction chamber side
Implementation Method 4
a pressure relief passage that relieves a refrigerant pressure in a pressure supply passage region between the first control valve and the check valve to the suction chamber side
Implementation Method 5
opening and closing means capable of opening and closing the pressure relief passage
Implementation Method 6
changes an inclination angle of a swash plate in the crank chamber to vary a discharge displacement
Data Source
AI summary
A variable displacement compressor which prevents leakage of a refrigerant flowing directly into a suction chamber without passing via a crank chamber at a time of a minimum discharge displacement operation, thus making it possible to prevent an increase of a minimum discharge displacement by increasing a refrigerant pressure in the crank chamber, and in addition, making it possible to prevent insufficient lubrication of sliding portions and the like in the crank chamber.