Vehicular air-conditioning device having a dehumidifying and heating mode
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Solution Overview
Problem
Vehicular air-conditioning devices with heat pump systems experience significant noise due to large pressure differences when opening/closing valves switch between operation modes, particularly during transitions from heating to dehumidifying and heating or cooling modes.
Innovation Solution
Implementing control means that decrease the pressure difference before and after the opening/closing valve to a predetermined value or less, by adjusting compressor revolutions, outdoor expansion valve positions, and blower air volumes, to minimize noise during mode changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the opening/closing valve opens during mode change from heating to dehumidifying and heating mode, then the refrigerant flow path is switched to enable dehumidifying function, but a large pressure difference causes the refrigerant to rapidly flow into the heat absorber generating significant noise
Solution Approach 1:
The control means decreases the pressure in the radiator to a predetermined value or less before opening the opening/closing valve. This preliminary pressure reduction action prevents the large pressure difference that would otherwise cause rapid refrigerant flow and noise when the valve opens during mode transition from heating to dehumidifying and heating mode.
Solution Approach 2:
The system changes the pressure parameter of the radiator from a high pressure state (during heating mode) to a predetermined low pressure state (before opening the valve for dehumidifying mode). This parameter change ensures that when the opening/closing valve opens, the pressure difference is minimized, preventing rapid refrigerant flow and associated noise.
2Adaptability or versatility
If the opening/closing valve for bypass opens during mode change from heating or dehumidifying and heating mode to cooling mode, then the refrigerant flow path is switched to enable cooling function, but a large pressure difference causes the refrigerant to rapidly flow into the outdoor heat exchanger generating significant noise
Solution Approach 1:
The control means decreases the pressure in the radiator to a predetermined value or less before opening the opening/closing valve for bypass. This preliminary pressure reduction action prevents the large pressure difference that would otherwise cause rapid refrigerant flow and noise when the valve opens during mode transition to cooling mode.
Solution Approach 2:
The system changes the pressure parameter of the radiator from a high pressure state (during heating or dehumidifying and heating mode) to a predetermined low pressure state (before opening the bypass valve for cooling mode). This parameter change ensures that when the opening/closing valve opens, the pressure difference is minimized, preventing rapid refrigerant flow and associated noise.
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
Effectively reduces noise generation by controlling the pressure differences and valve openings, ensuring smooth transitions between operation modes without significant noise disruption.
Implementation Method 1
a compressor which compresses a refrigerant
Implementation Method 2
a radiator which lets the refrigerant radiate heat to heat the air to be supplied from the air flow passage to the vehicle interior
Implementation Method 3
a heat absorber which lets the refrigerant absorb heat to cool the air to be supplied from the air flow passage to the vehicle interior
Implementation Method 4
an outdoor heat exchanger disposed outside the vehicle interior to let the refrigerant radiate or absorb heat
Implementation Method 5
decompresses at least a part of the refrigerant flowing out from the radiator
Data Source
AI summary
There is disclosed a vehicular air-conditioning device of a so-called heat pump system which eliminates or decreases noise generated when an opening/closing valve opens at a changing time of an operation mode. The vehicular air-conditioning device executes a heating mode to let a refrigerant discharged from a compressor 2 radiate heat in a radiator 4, decompress the refrigerant by which heat has been radiated, and then let the refrigerant absorb heat in an outdoor heat exchanger 7, and a dehumidifying and heating mode to open a solenoid valve 22 in a state of the heating mode, decompress at least a part of the refrigerant flowing out from the radiator and then let the refrigerant absorb heat in a heat absorber 9. When the heating mode changes to the dehumidifying and heating mode, the controller decreases a radiator pressure or a pressure difference before and after the solenoid valve to a predetermined value or less, and then opens the solenoid valve 22.