Vehicle HVAC Mode Selection for Stable Heating and Dehumidifying
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Solution Overview
Problem
Conventional air-conditioning apparatuses for vehicles face challenges in selecting the optimal operation mode, leading to inadequate heating capability and frequent mode changes, resulting in suboptimal air conditioning performance and comfort.
Innovation Solution
The air-conditioning apparatus includes a control system that selects operation modes based on outdoor air temperature, target outlet temperature, and radiator target temperature, ensuring that the radiator target temperature is achievable through heat radiation, thereby preventing unnecessary mode changes and maintaining stable and comfortable vehicle interior air conditioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the operation mode is changed based on conventional control (heating mode to dehumidifying and heating mode), then dehumidification performance is improved, but heating capability becomes insufficient and mode changes repeat frequently
Solution Approach 1:
The control means performs preliminary judgment before mode switching to determine whether the radiator can achieve the target temperature. This prevents switching to dehumidifying and heating mode when heating capability would be insufficient, thereby avoiding repeated mode changes and maintaining stable heating performance.
Solution Approach 2:
The control means continuously monitors the relationship between outdoor air temperature and target outlet temperature, and uses this feedback to judge whether mode switching is appropriate. This feedback mechanism ensures that mode changes are made only when heating capability requirements are satisfied, preventing unstable operation.
2Productivity
If the operation mode changes frequently to maintain optimal performance, then air conditioning performance is improved, but system stability deteriorates
Solution Approach 1:
Before executing mode switching, the control means preliminarily judges whether the target temperature can be achieved in the new mode. This preliminary check prevents switching to modes that would result in insufficient heating capability, thereby reducing unnecessary mode changes and improving system stability.
Solution Approach 2:
The control means uses feedback from temperature measurements and environmental conditions to determine whether mode switching should occur. This feedback control ensures that mode changes are made only when necessary and when the new mode can actually achieve the desired performance, preventing oscillatory behavior.
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 ensures rapid and stable vehicle interior air conditioning by selecting operation modes that maintain sufficient heating capability and prevent frequent mode changes, ensuring comfortable conditions regardless of environmental conditions.
Implementation Method 1
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 2
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 3
an outdoor heat exchanger disposed outside a vehicle interior to let the refrigerant radiate or absorb heat
Data Source
AI summary
There is disclosed an air-conditioning apparatus for vehicle which is capable of selecting an appropriate operation mode while inhibiting the operation mode from being unnecessarily changed, and achieving rapid and stable vehicle interior air conditioning. A controller has respective operation modes of a heating mode, a dehumidifying and heating mode, a dehumidifying and cooling mode, and a cooling mode, and selects and executes these operation modes. The controller has a dehumidifying and heating mode maximum radiator temperature MAP and a dehumidifying and cooling mode maximum radiator temperature MAP. The controller selects an operation mode in which a radiator target temperature TCO is achievable by heat radiation in a radiator 4 with reference to each MAP, on startup or at a time of change of the operation mode.