Refrigerator and method of controlling the same
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Solution Overview
Problem
Existing refrigerator control methods result in significant temperature variations within storage compartments, leading to reduced food freshness and difficulties in precise temperature control due to the placement of temperature sensors, which are not sensitive to cooling air influences.
Innovation Solution
A method involving a control unit that adjusts the output of a cooling unit over predetermined reference times to maintain a constant storage compartment temperature, varying the first and second reference times based on temperature differences to ensure the average temperature remains within a set range, thereby optimizing the operation of the compressor and fan units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the compressor and fan are driven when the temperature reaches the upper limit and stopped when the temperature reaches the lower limit, then the temperature control cycle maintains basic cooling function, but the storage compartment experiences great temperature variation width which lowers food freshness
Solution Approach 1:
The patent applies periodic action by implementing multiple temperature control cycles within one freezing cycle. Instead of a single on/off cycle, the system performs periodic cooling actions at different stages (first cooling action when temperature reaches upper limit, second cooling action when temperature reaches intermediate value) to create more frequent, smaller temperature adjustments rather than large variations.
Solution Approach 2:
The patent segments the temperature control process into multiple distinct stages: monitoring phase, first cooling action phase (when temperature reaches upper limit), intermediate monitoring phase, and second cooling action phase (when temperature reaches intermediate value). This segmentation allows for more precise control by treating different temperature ranges as separate control zones rather than a single binary control system.
2Ease of operation
If the temperature sensor is installed in a place less sensitive to cooling air influence, then the sensor installation is easier and more stable, but it becomes difficult to precisely and constantly control the temperature
Solution Approach 1:
The patent implements feedback control by continuously monitoring the storage compartment temperature and comparing it against predetermined thresholds (upper limit and intermediate values). Based on this feedback, the system automatically adjusts cooling operations - initiating first cooling action when upper limit is reached, and second cooling action when intermediate value is reached, creating a closed-loop control system that maintains precision without requiring the sensor to be in a highly sensitive location.
Solution Approach 2:
The patent changes the control parameters by introducing multiple temperature thresholds (upper limit temperature and intermediate temperature value) instead of relying solely on a single setpoint temperature. This multi-threshold approach allows the system to achieve precise temperature control through staged cooling actions, compensating for the reduced sensitivity of the temperature sensor installation location.
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 enhances food freshness by maintaining a stable storage compartment temperature, reduces temperature variation at the sensor installation point, and allows for effective control even with lower resolution temperature sensors.
Implementation Method 1
controlling a cooling unit such that an output of the cooling unit becomes a first reference output for a first reference time which is previously determined
Data Source
AI summary
A method of controlling a refrigerator includes: controlling a cooling unit such that an output of the cooling unit becomes a first reference output for a first reference time previously determined; controlling the cooling unit such that the output of the cooling unit becomes a second reference output for a second reference time previously determined; calculating a representative value of a temperature of a storage compartment for an operating period, which is made by a sum of the first reference time and the second reference time, and comparing the calculated representative value with a specific temperature in a temperature satisfying range of the storage compartment; and varying, by a control unit, at least one of the first reference time and the second reference time depending on a comparison result between the specific temperature and the representative value and controlling operating of the cooling unit based on a varied reference time.