Indirect Reversible AC Circuit Bypass Control for Dehumidification

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Solution Overview

Problem

In motor vehicle air conditioning systems, especially in total dehumidification mode, the air entering the passenger compartment can become too hot due to high heat energy generation, compromising comfort and dehumidification, particularly when cooling electric components, leading to inadequate temperature control.

Innovation Solution

An indirect reversible air conditioning circuit with a central control unit managing refrigerant fluid redirection through a bypass loop, using temperature sensors to adjust refrigerant flow and compressor speed to maintain optimal interior air temperature, ensuring simultaneous operation of heat exchangers for efficient dehumidification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the air conditioning circuit operates in total dehumidification mode with high heat energy generation, then dehumidification function is improved, but the air temperature becomes too hot compromising comfort

Engineering Contradiction:
Improvedehumidification functionVSAvoidair temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent implements dynamic control of the refrigerant circulation system by adjusting compressor speed and redirecting refrigerant flow between different heat exchangers based on real-time temperature measurements. The control unit continuously monitors air temperature and modifies system operation to maintain comfort while preserving dehumidification effectiveness.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters including refrigerant flow distribution, compressor speed, and heat exchanger configuration based on temperature conditions. By varying these parameters dynamically, the system can shift between dehumidification-priority mode and comfort-priority mode to resolve the temperature contradiction.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the refrigerant fluid flows through the second heat exchanger to cool external air, then heat exchange efficiency is improved, but the interior air temperature control becomes inadequate

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoidinterior air temperature
Core Design Contradiction:
Loss of energyVSTemperature

Solution Approach 1:

The patent applies different operational characteristics to different parts of the refrigerant circulation system. The first heat exchanger operates optimized for interior air conditioning while the second heat exchanger handles external air cooling. This local optimization allows each component to perform its specific function effectively without compromising the other.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The control unit acts as an intermediary that coordinates between the two heat exchangers and the compressor. It receives temperature feedback and adjusts refrigerant flow distribution and compressor operation to balance the competing demands of interior comfort and external heat exchange efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the air conditioning circuit is used to cool electric components, then component cooling function is improved, but the passenger compartment temperature control deteriorates

Engineering Contradiction:
Improvecomponent cooling functionVSAvoidpassenger compartment temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent segments the thermal management system into separate functional zones: interior air conditioning, external air cooling, and component cooling. Each zone has dedicated heat exchangers and control pathways, allowing independent optimization of each function without interfering with the others.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The refrigerant circulation system is designed with multi-functionality to handle diverse thermal management tasks. The same refrigerant loop serves interior cooling, external heat exchange, and component cooling needs, with the control unit dynamically allocating refrigerant flow to meet the most critical demand at any given time.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 regulates air temperature and maintains dehumidification functionality by redirecting refrigerant fluid based on temperature setpoints, preventing overheating and ensuring comfortable interior conditions while managing heat energy effectively.

Implementation Method 1

a first two-fluid heat exchanger arranged jointly on the first refrigerant fluid loop and on a second heat-transfer fluid loop in which a first heat-transfer fluid circulates, the first two-fluid heat exchanger being arranged so as to allow heat exchanges between the first refrigerant fluid loop and the second heat-transfer fluid loop

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a first heat exchanger being intended to be crossed by a flow of air inside the motor vehicle

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 3

a second heat exchanger being intended to be traversed by a flow of air external to the motor vehicle

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 4

a compressor

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 5

a first expansion device, a second expansion device

Methodology Applied
Scientific EffectExpansion: Pressure Drop

Data Source

PatentEP3661776B1Indirect reversible air-conditioning circuit for a motor vehicle
Publication Date: 2022.01.05 VALEO SYST THERMIQUES SAS
  • EP3661776B1 patent drawingFigure 1~2
  • EP3661776B1 patent drawingFigure 3~4
  • EP3661776B1 patent drawingFigure 5~7

AI summary

The present invention relates to a method for managing an indirect reversible air-conditioning circuit (1) for a motor vehicle comprising a first coolant loop (A), wherein a coolant circulates, and a second heat-transfer fluid loop (B), wherein a first heat-transfer medium circulates, when the indirect air-conditioning circuit (1) is in total dehumidification mode, the central control unit (90) controls the device for redirecting the coolant such that: if the temperature measured at the temperature sensor (73) of the inner airflow (100) is greater than or equal to T + Y1, a device for redirecting the coolant allows the coolant to pass through the bypass loop (30), wherein T is a temperature setpoint value of the inner airflow (100) at the temperature sensor (73) and Y1 a temperature differential of between 0 and 3°C, if the temperature measured at the level of the temperature sensor (73) of the inner airflow (100) is less than or equal to T - Y2, the device for redirecting the coolant prevents the coolant from passing through the bypass loop (30), wherein T is a temperature setpoint value of the inner airflow (100) at the temperature sensor (73) and Y2 a temperature differential of between 0 and 3°C. 25