Refrigeration cycle system
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Solution Overview
Problem
Conventional refrigeration cycle systems face challenges in accurately detecting insufficient refrigerant levels, particularly when outside air temperatures are low, leading to potential compressor damage due to erroneous determinations and increased costs from temperature sensors, and delayed detection.
Innovation Solution
A refrigeration cycle system that includes means to detect compressor current values at different times after startup, comparing these values to reference thresholds to determine if the refrigerant is insufficient, thereby preventing compressor damage without relying on temperature sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the current value of the compressor is simply compared with the reference value to detect insufficient refrigerant, then the detection method is simple, but erroneous determination occurs when the outside air temperature is low
Solution Approach 1:
The patent changes the detection parameters from a single current value comparison to a combination of multiple current values measured at different time points (first detection value at time t1, second detection value at time t2). This parameter change allows the system to distinguish between low current caused by low ambient temperature and low current caused by refrigerant insufficiency, thereby improving detection accuracy without significantly increasing system complexity.
2Measurement precision
If a temperature sensor is used to detect fluid temperature of the radiator outlet for refrigerant insufficiency determination, then the detection accuracy is improved, but the cost is increased and the detection time is extended
Solution Approach 1:
The patent replaces the temperature sensor-based detection method with an electrical measurement method using current detectors. Instead of measuring fluid temperature at the radiator outlet (which requires physical temperature sensors and waiting for temperature stabilization), the system measures compressor current at two different time points after startup. This substitution eliminates the need for temperature sensors and reduces detection time while maintaining sufficient detection accuracy.
3Temperature
If the target temperature of the radiator outlet is set low to improve cooling efficiency, then the cooling performance is improved, but the temperature difference for refrigerant insufficiency detection is reduced
Solution Approach 1:
The patent introduces compressor current as an intermediary parameter for detecting refrigerant insufficiency, rather than relying directly on the temperature difference at the radiator outlet. The current values measured at different time points serve as a mediator that reflects the refrigerant state without being directly affected by the radiator outlet temperature setting. This allows the system to maintain low target temperatures for cooling efficiency while preserving reliable refrigerant insufficiency detection capability.
Data Source
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Figure 3~4
AI summary
A first detection value I1, which is a value of a compressor current at a point of time when a first time has elapsed from starting of a compressor is acquired (Step S6). A second detection value 12, which is a value of the compressor current at a point of time when a second time has elapsed from the starting of the compressor is acquired (Step S5). In a case where the first detection value I1 does not exceed a first reference value Iα and a difference between the first detection value I1 and the second detection value 12 does not exceed a second reference value Iβ, the compressor is stopped (Step S10),