Vehicle AC Expansion Valve Control With Shared Refrigerant Sensing

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Solution Overview

Problem

The existing air conditioning devices for vehicles face challenges in size and manufacturing cost due to the increased number of detectors required for temperature and pressure detection in each expansion valve, which compromises cooling and heating efficiency.

Innovation Solution

An air conditioning device design that incorporates a single temperature sensor and pressure sensor in the inter-expansion valve line to detect the state quantity of refrigerant, allowing for controlled opening degrees of the expansion valves, thereby enhancing cooling and heating capacity while minimizing the number of detectors and device size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If temperature detector and pressure detector are provided in each expansion valve, then cooling and heating capacity is enhanced, but device size increases and manufacturing cost increases

Engineering Contradiction:
Improvecooling and heating capacityVSAvoiddevice size
Core Design Contradiction:
ProductivityVSVolume of stationary object

Solution Approach 1:

The patent merges the detection functions for both expansion valves into a single detector unit. The detector is positioned to measure refrigerant temperature and pressure at a location that reflects the state of refrigerant for both the first and second expansion valves, eliminating the need for separate detectors in each valve and thereby reducing device size while maintaining control capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single detector unit serves multiple functions by monitoring refrigerant conditions that are relevant to both expansion valves. The detector's measurements are used by the controller to regulate both the first and second expansion valves, making the detection system universal rather than dedicated to a single valve.

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

2Productivity

If temperature detector and pressure detector are provided in each expansion valve, then cooling and heating efficiency is enhanced, but manufacturing cost increases

Engineering Contradiction:
Improvecooling and heating efficiencyVSAvoidmanufacturing cost
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The patent combines multiple detection functions into a single detector unit, reducing the total number of detectors required. This merging of functions lowers component count, simplifies assembly, and reduces manufacturing cost while still enabling efficient control of both expansion valves through centralized refrigerant state monitoring.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The detector is designed with universal applicability to monitor refrigerant conditions for both expansion valves. This multi-functional detector reduces the need for multiple specialized detectors, thereby lowering manufacturing costs while maintaining the ability to optimize cooling and heating efficiency through accurate refrigerant state detection.

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

3Measurement precision

If multiple detectors are provided in each expansion valve, then refrigerant state detection precision is improved, but device complexity increases

Engineering Contradiction:
Improverefrigerant state detection precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the detection capabilities into a single integrated detector unit that measures both temperature and pressure of the refrigerant. This unified detector reduces device complexity by eliminating multiple separate detectors and their associated mounting structures, while still providing comprehensive refrigerant state information for precise control of both expansion valves.

Inventive Principle:
Principle #5Merging (Combining)

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 suppresses the increase in device size and manufacturing cost while improving cooling and heating efficiency by using a single set of detectors to control the expansion valves, thus optimizing refrigerant flow and capacity.

Implementation Method 1

The expansion valve control detector includes only one temperature sensor provided in the inter-expansion valve line or the inter-expansion valve connection line to detect a temperature of the refrigerant

Methodology Applied
Scientific EffectTemperature detection:

Implementation Method 2

only one pressure sensor provided in the inter-expansion valve line or the inter-expansion valve connection line to detect a pressure of the refrigerant

Methodology Applied
Scientific EffectPressure detection:

Implementation Method 3

a compressor that compresses a refrigerant

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 4

an indoor condenser that performs heat exchange between the refrigerant and indoor air to cool and condense the refrigerant

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 5

an indoor condenser that performs heat exchange between the refrigerant and indoor air to cool and condense the refrigerant

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 6

an indoor evaporator that performs heat exchange between the refrigerant and the indoor air to heat and evaporate the refrigerant

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 7

an indoor evaporator that performs heat exchange between the refrigerant and the indoor air to heat and evaporate the refrigerant

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 8

an outdoor heat exchanger that performs heat exchange between the refrigerant and outside air to function as a condenser that cools and condenses the refrigerant during cooling and function as an evaporator that heats and evaporates the refrigerant during heating

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 9

a first expansion valve that expands the refrigerant in a liquid phase and sends the refrigerant to the indoor evaporator

Methodology Applied
Scientific EffectExpansion:

Implementation Method 10

a second expansion valve that expands the refrigerant in a liquid phase and sends the refrigerant to the outdoor heat exchanger

Methodology Applied
Scientific EffectExpansion:

Data Source

PatentEP3828020B1Air conditioning device for vehicle
Publication Date: 2023.11.08 MITSUBISHI HEAVY IND THERMAL SYST
  • EP3828020B1 patent drawingFigure 1
  • EP3828020B1 patent drawingFigure 2
  • EP3828020B1 patent drawingFigure 3

AI summary

This air conditioning device for a vehicle comprises: an indoor condenser (14); an indoor evaporator (13); a first expansion valve (22); a second expansion valve (23); a refrigerant line (40); an expansion valve control detector (30); and a controller (50). The expansion valve control detector (30) is constituted by: only one temperature sensor (31) that detects the temperature of refrigerant in an inter-expansion valve line (44) of the refrigerant line (40); and only one pressure sensor (32) that detects the pressure of the refrigerant in the inter-expansion valve line (44). During a cooling operation, the controller (50) issues, to the first expansion valve (22), an opening command corresponding to a state quantity of the refrigerant that has been detected by the expansion valve control detector (30), and during a heating operation, the controller issues, to the second expansion valve (23), an opening command corresponding to a state quantity of the refrigerant that has been detected by the expansion valve control detector (30).