Method for operating a refrigerant circuit of a cooling system of a vehicle
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In refrigerant circuits of vehicle cooling systems, operating in single chiller mode leads to higher low pressure levels, causing refrigerant density increase and risk of premature overheating, as well as undercooling issues due to inadequate refrigerant supply at the condenser or gas cooler.
Innovation Solution
The method involves a chiller branch with a first expansion element, an interior evaporator branch in parallel, and a segmentation element to prevent backflow, with the refrigerant compressor aspirating from the interior evaporator by closing the second expansion element and generating suction pressure, allowing operation at higher low pressure levels for increased efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the refrigerant circuit operates in single chiller mode with the interior evaporator active, then the cooling capacity for the battery is provided, but the low pressure level increases causing refrigerant density increase and risk of premature overheating
Solution Approach 1:
The patent extracts the harmful effect of high refrigerant density and premature overheating by introducing a second expansion element that can be closed to isolate the interior evaporator branch. This allows the system to remove the problematic low pressure condition while maintaining the desired cooling capacity through the chiller branch alone.
Solution Approach 2:
The system dynamically adjusts the configuration of the refrigerant circuit by providing controllable expansion elements that can change their state (open/closed) based on operating conditions. This allows transition between different operational modes (single chiller mode, dual evaporator mode) to optimize performance and avoid harmful effects under varying load conditions.
2Power
If the refrigerant circuit operates in single chiller mode, then the battery cooling is achieved, but undercooling issues occur due to inadequate refrigerant supply at the condenser or gas cooler
Solution Approach 1:
The patent removes the problematic interaction between the interior evaporator and chiller branch by introducing a closure mechanism (second expansion element) that can isolate the interior evaporator. This extraction of the problematic component allows the chiller branch to operate independently with adequate refrigerant supply, eliminating undercooling issues while maintaining battery cooling capability.
3Loss of energy
If the second expansion element is closed to aspirate refrigerant from the interior evaporator, then the low pressure level is reduced improving efficiency, but the refrigerant volume flow must be optimized
Solution Approach 1:
The system employs feedback control through the controllable expansion elements that monitor and adjust refrigerant flow based on operating conditions. By closing the second expansion element and adjusting the first expansion element, the system feedback-regulates the refrigerant volume flow to maintain optimal pressure ratio and efficiency while preventing both overheating and undercooling conditions.
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 maintains higher efficiency by establishing a lower pressure ratio between high and low pressure sides, optimizing refrigerant volume flow, and preventing overheating or undercooling, ensuring the battery is not exposed to extreme temperature differences.
Implementation Method 1
aspirating the refrigerant from the interior evaporator by means of the starting or already started refrigerant compressor
Implementation Method 2
establishing a lower pressure ratio between high and low pressure sides, optimizing refrigerant volume flow
Implementation Method 3
a chiller branch which comprises a chiller and a first expansion element connected upstream from it and being thermally coupled to a coolant circuit
Data Source
AI summary
A method of operating a refrigerant circuit of a cooling system of a vehicle in cooling system mode, having a chiller branch which includes a chiller and a first expansion element connected upstream from it and being thermally coupled to a coolant circuit, at least one interior evaporator branch connected in parallel with the chiller branch, comprising an interior evaporator, a second expansion element connected upstream from it, and a segmentation element connected downstream from the interior evaporator, being adapted to prevent a backflow of refrigerant into the interior evaporator, a refrigerant compressor, and a condenser or gas cooler, wherein the cooling system mode is carried out in single chiller mode by closing the second expansion element and aspirating the refrigerant from the interior evaporator by the starting or already started refrigerant compressor.