Variable Displacement Compressor Valve Timing Control
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Solution Overview
Problem
The existing displacement control mechanisms for variable displacement type compressors suffer from inefficiencies due to improper timing of the second control valve's operation, leading to prolonged startup times and reduced operating efficiency, especially when the compressor is started after a long idle period or when the clutch mechanism is involved.
Innovation Solution
A displacement control mechanism that includes a second control valve with a back pressure chamber communicating with the supply passage, a valve chamber forming part of the release passage, and a spool with a valve portion, allowing the valve hole to adjust its degree of opening based on pressure changes, and a check valve to prevent the pressure control chamber's pressure from affecting the back pressure chamber, ensuring optimal timing for the second control valve's operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a fixed throttle is provided in the release passage to decrease the cross-sectional area, then the operating efficiency of the compressor is improved, but the release of liquefied refrigerant is delayed causing excessive pressure increase in the pressure control chamber
Solution Approach 1:
The patent replaces the fixed throttle with a dynamically adjustable second control valve that can change the cross-sectional area of the release passage. The valve opens to a larger area during startup to rapidly discharge liquefied refrigerant, then closes to a smaller area during normal operation to maintain operating efficiency. This dynamic adjustment resolves the contradiction between startup performance and operating efficiency.
2Loss of energy
If the cross-sectional area of the release passage is made small to improve operating efficiency, then energy loss is reduced, but the compressor startup time is prolonged
Solution Approach 1:
The patent implements preliminary action by having the second control valve automatically open to a large cross-sectional area when the compressor starts, enabling rapid discharge of accumulated liquefied refrigerant before normal operation begins. After the startup phase, the valve transitions to a closed position with small opening to maintain efficient operation. This preliminary large-opening action resolves the time loss during startup while preserving operating efficiency.
3Productivity
If the second control valve operates with improper timing, then the displacement adjustment is delayed, but providing complex control mechanisms increases device complexity
Solution Approach 1:
The patent employs feedback mechanisms where the first control valve's opening degree provides feedback control for the second control valve. The ECU monitors the operating state and automatically adjusts the second control valve's opening timing and degree based on this feedback. This feedback-based control achieves proper timing for rapid displacement adjustment without requiring overly complex control mechanisms, as the system self-regulates based on operating conditions.
4Ease of operation
If the pressure control chamber pressure affects the back pressure chamber, then the second control valve operation timing becomes improper, but isolating the chambers requires additional valves
Solution Approach 1:
The patent extracts the back pressure chamber from the pressure control chamber by installing a check valve that blocks the communication path between them. This extraction prevents the pressure control chamber pressure from affecting the back pressure chamber, ensuring the second control valve operates with proper timing based solely on its own back pressure conditions. The check valve provides this isolation with minimal additional complexity.
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 enables the second control valve to operate at the proper timing, preventing the deterioration of compressor efficiency and ensuring rapid startup and optimal displacement adjustment, even under varying conditions such as idle periods and clutch mechanisms.
Implementation Method 1
a check valve provided between the first control valve and the pressure control chamber and preventing the refrigerant gas from flowing from the pressure control chamber to the first control valve by closing the supply passage
Implementation Method 2
a spool having a valve portion located in the valve chamber. When a pressure in the back pressure chamber increases, the valve portion decreases the degree of opening of the valve hole
Data Source
AI summary
A variable displacement type compressor has a supply passage for supplying refrigerant gas to a pressure control chamber, a release passage for releasing the refrigerant gas from the pressure control chamber, a first control valve for controlling the amount of the refrigerant gas flowing through the supply passage, a check valve provided between the first control valve and the pressure control chamber and preventing the refrigerant gas from flowing from the pressure control chamber to the first control valve by closing the supply passage and a second control valve for adjusting a cross-sectional area of the release passage from minimum to maximum. The second control valve has a back pressure chamber communicating with the supply passage, a valve chamber forming a part of the release passage and communicating with a suction-pressure region, a valve hole forming a part of the release passage and communicating with the valve chamber and a spool having a valve portion located in the valve chamber. When a pressure in the back pressure chamber increases, the valve portion decreases the degree of opening of the valve hole.