Variable displacement swash plate type compressor
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Solution Overview
Problem
Conventional variable displacement swash plate type compressors face challenges in maintaining high volumetric efficiency at low displacement, struggling to rapidly drain liquid refrigerant from the crank chamber during startup, which increases manufacturing costs and reduces design flexibility due to the need for additional components.
Innovation Solution
The compressor incorporates a valve chamber with a first and second valve body and a bias spring, where the second valve body opens the bleed passage when the suction pressure is lower than the set suction pressure and the crank chamber pressure is higher, allowing rapid drainage of liquid refrigerant and adjusting the suction and bleed passages to optimize displacement without additional bleed valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the opening area of the bleed passage is set large, then liquid refrigerant can be rapidly drained at startup, but volumetric efficiency at low displacement deteriorates due to re-compression of high-pressure refrigerant
Solution Approach 1:
The patent applies dynamics by making the bleed passage opening area variable rather than fixed. The second valve body dynamically adjusts the opening area of the bleed passage based on operating conditions: fully open during startup to rapidly drain liquid refrigerant, and closed during low displacement operation to prevent re-compression and maintain volumetric efficiency. This dynamic adjustment resolves the contradiction between rapid drainage capability and volumetric efficiency maintenance.
2Productivity
If a separate bleed valve is added to control the bleed passage opening area, then volumetric efficiency at low displacement improves, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the functions of the opening degree regulating valve and the bleed valve into a single integrated valve mechanism. The first valve body controls the suction passage opening degree while the second valve body controls the bleed passage opening degree, both operated by a single valve assembly actuated by suction pressure and crank chamber pressure differential. This merging eliminates the need for a separate bleed valve, reducing device complexity and manufacturing cost while maintaining the ability to control bleed passage opening area for optimal volumetric efficiency.
Solution Approach 2:
The opening degree regulating valve is designed with multi-functionality, serving both as the opening degree regulating valve and as the bleed valve. The single valve assembly performs multiple functions: regulating suction passage opening degree via the first valve body, controlling bleed passage opening area via the second valve body, and responding to both suction pressure and crank chamber pressure. This multi-functionality reduces the number of components while achieving the desired control capabilities.
3Loss of energy
If the opening degree of the suction passage is increased to prevent suction pressure loss, then displacement increases, but pressure variation in suction pressure at low displacement increases causing noise
Solution Approach 1:
The patent applies local quality by making the suction passage opening degree variable rather than uniformly fixed. The first valve body locally adjusts the opening degree of the suction passage based on operating conditions: maintaining a larger opening during high displacement to prevent suction pressure loss and energy waste, and reducing the opening during low displacement to minimize pressure variation and noise. This localized, condition-dependent adjustment optimizes both energy efficiency and noise control.
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 configuration ensures quiet operation at low displacement, maintains high volumetric efficiency, and reduces manufacturing costs by eliminating the need for separate bleed valves, allowing rapid displacement increase during startup.
Implementation Method 1
a bias spring which connects the first valve body to the second valve body
Implementation Method 2
The first valve body and the second valve body move in the radial direction due to a differential pressure between a suction pressure of the refrigerant before the refrigerant is sucked into the suction chamber and a crank chamber pressure
Data Source
AI summary
When a suction pressure is lower than a set suction pressure, and a crank chamber pressure is higher than a control pressure in a second supply passage, a first valve body reduces an opening degree of a suction passage, and a second valve body opens a bleed passage. When the suction pressure is higher than the set suction pressure, and the crank chamber pressure is higher than the control pressure, the first valve body increases the opening degree of the suction passage, and the second valve body opens the bleed passage. When the crank chamber pressure is lower than the control pressure, the first valve body reduces the opening degree of the suction passage, and the second valve body closes the bleed passage.