Method for managing an inversible air conditioning circuit for a motor vehicle
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Solution Overview
Problem
Current air conditioning systems in vehicles face challenges in efficiently managing the invertible air conditioning circuit, particularly in heat pump mode, where controlling the expansion device's opening to achieve optimal overheating and prevent refrigerant fluid overpressure is complex and often results in suboptimal heating performance.
Innovation Solution
A method for managing the air conditioning circuit that determines the opening of the first expansion device based on the pressure difference between the compressor and evaporator outputs, temperature of the second heat transfer fluid, and compressor speed, using a central control unit to adjust the setpoint overheating and maintain it within specific limits, while protecting against overpressure by adjusting the expansion device's opening dynamically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the expansion device opening is controlled to achieve optimal overheating in heat pump mode, then heating power is improved, but the system complexity and control difficulty increase
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the expansion device opening based on multiple measured parameters (compressor discharge pressure, evaporator outlet pressure, ambient temperature, compressor speed) to optimize overheating and heating power. The control strategy modifies operational parameters in real-time to achieve optimal performance without increasing hardware complexity
Solution Approach 2:
The patent implements feedback control by continuously measuring system parameters (pressures, temperatures) and using this information to adjust the expansion device opening. The control unit receives feedback from sensors and modifies the expansion device position to maintain optimal overheating levels, creating a closed-loop control system that improves heating power while managing complexity through intelligent control
2Reliability
If the expansion device opening is reduced to prevent refrigerant overpressure, then system safety is improved, but heating performance deteriorates
Solution Approach 1:
The patent applies dynamics by making the expansion device opening dynamic rather than static. The opening position continuously adapts based on real-time system conditions (pressures, temperatures, ambient conditions) to balance safety requirements with heating performance. This dynamic adjustment allows the system to prevent overpressure while maintaining optimal heating power under varying operating conditions
Solution Approach 2:
The patent uses parameter changes to resolve the safety-performance contradiction by adjusting the expansion device opening based on multiple changing parameters. When system pressure approaches safety limits, the opening is reduced; when safety margins are adequate, the opening is increased to optimize heating performance. This continuous parameter adjustment balances reliability and power output
3Productivity
If the expansion device opening is increased to improve heat transfer, then heating efficiency is improved, but refrigerant overpressure risk increases
Solution Approach 1:
The patent implements feedback control to manage the trade-off between heating efficiency and refrigerant pressure. Sensors continuously monitor compressor discharge pressure and evaporator outlet pressure, and this feedback information is used to adjust the expansion device opening. When pressure rises toward dangerous levels, the feedback loop reduces the opening to prevent overpressure while minimizing impact on heating efficiency
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 method enhances the heating power of the air conditioning system by effectively controlling the expansion device's opening, preventing refrigerant overpressure, and maintaining optimal overheating levels, leading to improved performance in heat pump mode.
Implementation Method 1
an evaporator-condenser intended to recover heat energy from a second heat transfer fluid and transfer it to the refrigerant fluid
Implementation Method 2
a condenser intended to release heat energy from the refrigerant fluid into a first heat transfer fluid
Implementation Method 3
a first expansion device in which the refrigerant fluid undergoes a first pressure loss
Data Source
Figure 1a~1b
Figure 2~3
Figure 4
AI summary
The present invention relates to a method for managing an indirect reversible air conditioning circuit (1) in which a refrigerant circulates, said reversible air conditioning circuit (1) being able to operate in a heat-pump mode in which the refrigerant passes in succession into : a compressor (3), a condenser (5), a first expansion device (7), an evaporator (9), a second expansion device (11), and an evaporator-condenser (13), said air conditioning circuit (1) comprising a central control unit (40) able to control the opening of the first expansion device (7), said management method comprissing: a step of determining: the opening Cestim of the first expansion device (7), a reference superheating SHcomp_in_sp, SHcomp_in_sp being comprised between a minimum superheating SHcomp_in_sp_min and a maximum superheating Shcomp_in_sp_max, a step of opening the expansion device (7) according to Cestim and of controlling the superheating SHcomp_in by varying the opening of the expansion device (7) so as to achieve the reference superheating SHcomp_in_sp and keep SHcomp_in between SHcomp_in_sp_min and SHcomp_in_sp_max.