Vehicular Air-Conditioning Compressor Startup Control
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Solution Overview
Problem
In vehicular air-conditioning devices, particularly for hybrid and electric cars, the startup of the compressor leads to a rapid pressure drop in the accumulator due to refrigerant boiling, causing bumping and excessive liquid return, which impairs compressor reliability and generates noise, especially in low outdoor temperatures.
Innovation Solution
The air-conditioning device employs a control mechanism that adjusts the compressor's startup speed and operation time based on outdoor temperature, using valve position limiting control for the outdoor expansion valve and managing the opening/closing valve to prevent rapid pressure changes, thereby inhibiting bumping and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compressor starts at high speed to quickly cool the vehicle interior, then the cooling efficiency is improved, but the pressure drop in the accumulator causes bumping and excessive liquid return which impairs compressor reliability
Solution Approach 1:
The patent applies dynamics by making the compressor startup speed variable rather than fixed. The control device adjusts the startup speed based on refrigerant density conditions, transitioning from a static system to a dynamic one that adapts to changing environmental conditions, thereby preventing bumping while maintaining cooling efficiency.
Solution Approach 2:
The patent changes the parameter of compressor startup speed based on outdoor temperature and refrigerant density. By adjusting this parameter dynamically, the system prevents excessive pressure drop and liquid return while maintaining effective cooling performance.
2Loss of time
If the compressor starts at high speed to quickly respond to cooling demand, then the response time is reduced, but the rapid pressure drop generates loud noise that impairs passenger comfort
Solution Approach 1:
The patent changes the compressor startup speed parameter based on outdoor temperature conditions. By adjusting this parameter, the system achieves a balance between response time and noise generation, preventing bumping-related noise while maintaining acceptable cooling response.
3Productivity
If the outdoor expansion valve opens fully to maximize refrigerant flow, then the cooling capacity is improved, but the rapid refrigerant flow causes excessive pressure drop and bumping in the accumulator
Solution Approach 1:
The patent applies dynamics by making the outdoor expansion valve opening degree variable rather than fixed. The control device adjusts the valve opening based on compressor startup conditions and refrigerant density, preventing excessive pressure drop and bumping while maintaining cooling capacity.
Solution Approach 2:
The patent changes the valve opening degree parameter dynamically during compressor startup. This parameter adjustment prevents rapid refrigerant flow that would cause bumping, while still allowing sufficient refrigerant flow for effective cooling.
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 prevents compressor bumping and noise, enhancing the reliability and comfort of the air-conditioning system by regulating the refrigerant flow and pressure during startup, especially in high-density refrigerant environments.
Implementation Method 1
a compressor (2) to compress the refrigerant
Implementation Method 2
a radiator (4) disposed in this air flow passage to let the refrigerant radiate heat
Implementation Method 3
a radiator (4) disposed in this air flow passage to let the refrigerant radiate heat
Implementation Method 4
an outdoor heat exchanger (7) disposed outside the vehicle interior to let the refrigerant absorb heat
Implementation Method 5
an accumulator (12) connected to a refrigerant suction side of the compressor, and a control means (32), so that the control means lets the refrigerant discharged from the compressor radiate heat in the radiator (4), and decompresses the refrigerant from which the heat has been radiated, to let the refrigerant absorb heat in the outdoor heat exchanger (7)
Implementation Method 6
the refrigerant from which the heat has been radiated in this radiator absorb heat in the outdoor heat exchanger
Data Source
AI summary
Vehicular air-conditioning device capable of inhibiting liquid return and generation of noise in an accumulator on startup of a compressor, and improving reliability and comfort. A controller lets a refrigerant discharged from a compressor 2 radiate heat in a radiator 4, and decompresses the refrigerant from which the heat has been radiated, to let the refrigerant absorb heat in an outdoor heat exchanger 7, thereby heating a vehicle interior. On startup of the compressor 2, the controller continues an operation at a predetermined startup number of revolution for a predetermined time, and then raises a number of revolution of the compressor 2 to a predetermined target number of revolution at a predetermined rising speed, and changes the startup number of revolution of the compressor 2 so as to lower the startup number of revolution as the outdoor air temperature is higher, on the basis of an outdoor air temperature.