Vehicle Air Conditioner Heating Control for Pressure-Flow Balance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional vehicle air conditioners face challenges in maintaining a high refrigerant subcool degree and refrigerant flow rate during heating, leading to insufficient heating capability due to compressor revolution number and pressure limitations.
Innovation Solution
A vehicle air conditioner system with control means that adjusts the refrigerant subcool degree in the radiator and compressor revolution number based on high pressure, switching between high pressure priority and revolution number priority modes to maintain optimal heating performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the subcool degree of refrigerant in the radiator is increased to maintain high pressure within the controlling upper limit value, then the high pressure is suppressed, but the refrigerant flow rate decreases and heating capability becomes insufficient
Solution Approach 1:
The patent applies dynamics by making the control mode switchable between high pressure priority mode and revolution number priority mode. The control means dynamically adjusts the control strategy based on actual operating conditions, allowing the system to transition between maintaining high pressure and maintaining refrigerant flow rate as needed.
Solution Approach 2:
The patent changes the control parameter from fixed high pressure control to variable control that adjusts between two modes. In high pressure priority mode, the subcool degree is increased to suppress high pressure; in revolution number priority mode, the subcool degree is decreased to maintain refrigerant flow rate and heating capability.
2Stress or pressure
If the revolution number of the compressor is decreased to suppress high pressure within the controlling upper limit value, then the high pressure is maintained, but the refrigerant flow rate becomes small and heating capability is insufficient
Solution Approach 1:
The control means dynamically switches between controlling strategies, allowing the revolution number to be maintained at higher levels in revolution number priority mode while using subcool degree adjustment in high pressure priority mode when pressure suppression is needed.
Solution Approach 2:
The patent changes the control approach from directly limiting revolution number to a dual-mode system where revolution number can be maintained high in one mode or adjusted in another mode depending on system conditions and heating requirements.
3Reliability
If the control means maintains high pressure at the upper limit value, then pressure protection is achieved, but the refrigerant flow rate is reduced and heating capability runs short
Solution Approach 1:
The patent introduces dynamic mode switching that allows the system to operate in high pressure priority mode for pressure protection when needed, and switch to revolution number priority mode when heating capability is the primary concern, providing flexible reliability and performance management.
Solution Approach 2:
The control means changes the target subcool degree based on the selected mode: in high pressure priority mode, it increases subcool degree to maintain pressure at upper limit; in revolution number priority mode, it decreases subcool degree to maximize refrigerant flow and heating output.
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
The system effectively improves heating capability while maintaining high pressure and refrigerant flow rate, ensuring efficient operation in electric and hybrid vehicles by dynamically controlling the subcool degree and compressor settings.
Implementation Method 1
a compressor which compresses a refrigerant
Implementation Method 2
a radiator which lets the refrigerant radiate heat to heat air to be supplied into a vehicle interior
Implementation Method 3
an outdoor heat exchanger disposed outside the vehicle interior to let the refrigerant absorb heat
Implementation Method 4
an expansion valve which decompresses the refrigerant flowing into this outdoor heat exchanger
Data Source
AI summary
There is disclosed a vehicle air conditioner in which a refrigerant subcool degree of a radiator to satisfy both a high pressure and a refrigerant flow rate during heating can appropriately be controlled to achieve improvement of a heating capability. The vehicle air conditioner comprises a compressor 2 which compresses a refrigerant, a radiator 4 which lets the refrigerant radiate heat, an outdoor heat exchanger 7 disposed outside the vehicle interior to let the refrigerant radiate or absorb heat, and a controller. The controller executes a heating mode to let the refrigerant discharged from the compressor 2 radiate heat in the radiator 4, decompress the refrigerant by which heat has been radiated and then absorb heat in the outdoor heat exchanger 7. The controller 32 has a high pressure priority mode to increase a target radiator subcool degree TGSC of the radiator 4 in a direction in which the high pressure is set to a predetermined high value, and a revolution number priority mode to decrease the target radiator subcool degree of the radiator in a direction in which the revolution number of the compressor 2 is set to a predetermined high value.