Vehicle Thermal Circuit Control for Stable Cabin Air Temperature
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Solution Overview
Problem
Conventional in-vehicle temperature control systems face the challenge of temperature fluctuations in the air blown into the vehicle interior due to changes in the low-temperature-side heat medium, especially when the electric heater is not provided.
Innovation Solution
An in-vehicle temperature control system with a refrigeration circuit and a thermal circuit, controlled by a controller that adjusts heat absorption and flow rates of refrigerant and heat medium based on temperature changes, using heat exchangers and pumps to maintain consistent interior air temperature without an electric heater.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flow rate of refrigerant through the chiller is reduced to prevent compressor deterioration, then the durability of the compressor is improved, but the temperature of the blown air in heating mode decreases
Solution Approach 1:
The controller predicts temperature changes of the low-temperature-side heat medium in advance and preemptively adjusts the refrigerant flow rate or superheat level before the temperature change occurs, preventing both compressor damage and blown air temperature drops
Solution Approach 2:
The controller continuously monitors the temperature of the low-temperature-side heat medium and adjusts the refrigerant flow rate or superheat level based on feedback from temperature sensors, maintaining stable blown air temperature while protecting the compressor
2Productivity
If the temperature of the low-temperature-side heat medium changes significantly, then the cooling efficiency of the battery may improve, but the stability of the interior air temperature deteriorates
Solution Approach 1:
The system dynamically adjusts the refrigerant flow rate or superheat level in real-time based on the temperature of the low-temperature-side heat medium, allowing the system to adapt to temperature changes while maintaining stable interior air temperature
Solution Approach 2:
The controller changes operational parameters (refrigerant flow rate, superheat level) in response to temperature changes in the low-temperature-side heat medium, decoupling the temperature stability of the interior air from the temperature variations in the thermal circuit
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 stabilizes interior air temperature by dynamically adjusting refrigerant and heat medium flow rates and absorption, ensuring consistent heating or cooling regardless of low-temperature-side heat medium fluctuations.
Implementation Method 1
a first heat exchanger for absorbing heat from a first heat medium to a refrigerant to evaporate the refrigerant
Implementation Method 2
a second heat exchanger for releasing heat from the refrigerant to an outside to condense the refrigerant and being able to use the released heat for heating an interior of the vehicle
Implementation Method 3
an external heat exchanger for absorbing heat from an outside to the first heat medium
Data Source
AI summary
A system includes a refrigeration circuit, low-temperature circuit and controller. The refrigeration circuit includes: a tiller for absorbing heat from a colling water to a refrigerant; and a condenser for releasing heat from the refrigerant to an outside, and realizes a refrigeration cycle by circulating the refrigerant therethrough. The low-temperature circuit includes the tiller and an external heat exchanger for absorbing heat from an outside to the first heat medium, and circulate the cooling water therethrough. The controller can change a heat absorption amount of the refrigerant at the tiller. The controller controls the device so that a change in the heat absorption amount of the refrigerant at the first heat exchanger in accordance with a change in a temperature of the first heat medium is reduced, if the temperature of the cooling water flowing through the first heat exchanger changes by a reference value or more.