Vehicle Air Conditioning Compressor Pressure Control
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Solution Overview
Problem
Conventional air conditioning devices for vehicles face limitations in heating performance due to compressor shutdown when discharge pressure increases with rising engine coolant temperature, leading to inefficient operation.
Innovation Solution
Incorporating a three-way valve to adjust the flow rate of engine coolant, allowing it to bypass the first water-refrigerant heat exchanger, thereby reducing heat exchange effectiveness and lowering refrigerant pressure, which in turn suppresses the rise in compressor discharge pressure, allowing for increased compressor ON time and improved heating performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the engine coolant temperature is increased to improve heating performance, then the heating capability is enhanced, but the compressor discharge pressure rises causing the compressor to shut off
Solution Approach 1:
The patent changes the flow rate parameter of engine coolant through the first water-refrigerant heat exchanger. By reducing the coolant flow rate through this heat exchanger, the heat exchange effectiveness between engine coolant and refrigerant is decreased, which lowers refrigerant pressure and suppresses the rise in compressor discharge pressure, allowing the compressor to continue operating even at higher engine coolant temperatures
Solution Approach 2:
The first flow rate adjusting unit acts as an intermediary device between the engine coolant system and the refrigerant system. It controls and regulates the coolant flow rate through the first water-refrigerant heat exchanger, mediating the interaction between these two systems to prevent excessive refrigerant pressure rise while maintaining effective heating
2Power
If the heat exchange effectiveness between engine coolant and refrigerant is increased to improve heating performance, then more heat is transferred to the refrigerant, but the refrigerant pressure rises causing compressor shutdown
Solution Approach 1:
The patent changes the flow rate parameter of engine coolant through the first water-refrigerant heat exchanger. By reducing the coolant flow rate through this heat exchanger, the heat exchange effectiveness between engine coolant and refrigerant is decreased, which lowers refrigerant pressure and suppresses the rise in compressor discharge pressure, allowing the compressor to continue operating even at higher engine coolant temperatures
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 solution effectively reduces the compressor's OFF control ratio, enhancing heating performance by maintaining compressor operation even at higher engine coolant temperatures, thus providing more efficient heating in vehicle interiors.
Implementation Method 1
heat exchange effectiveness between the engine coolant and the refrigerant at the first water-refrigerant heat exchanger
Data Source
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AI summary
An air conditioning device for a vehicle includes a first water-refrigerant heat exchanger, a second water-refrigerant heat exchanger, and a first flow rate adjusting unit. The first water-refrigerant heat exchanger exchanges heat between a refrigerant of low-temperature and low-pressure in a heat pump and an engine coolant flowing in an engine coolant path to vaporize the refrigerant. The second water-refrigerant heat exchanger exchanges heat between the refrigerant of high-temperature and high-pressure and the engine coolant to condense the refrigerant. The first flow rate adjusting unit is capable of adjusting a flow rate of the engine coolant supplied to a flow path connecting with the first water-refrigerant heat exchanger, and a flow rate of the engine coolant supplied to a flow path bypassing the first water-refrigerant heat exchanger.