Electronic expansion valve, heat exchange system and method for controlling electronic expansion valve

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Solution Overview

Problem

Electronic expansion valves in heat exchange systems are limited by the high cost of pressure sensors, which account for a significant portion of the overall expense, hindering widespread application due to their high price.

Innovation Solution

An electronic expansion valve that utilizes multiple temperature sensors to control the opening degree of the valve body based on temperature signals from the evaporator, compressor inlet, compressor outlet, and condenser, eliminating the need for pressure sensors and reducing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pressure sensors are used to control the electronic expansion valve, then control accuracy is improved, but cost increases significantly

Engineering Contradiction:

Improvecontrol accuracyVSAvoidcost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent removes the pressure sensor from the system and extracts only the necessary temperature measurement functions. By using temperature sensors to detect evaporator temperature and compressor inlet temperature, the system calculates superheat degree without requiring direct pressure measurement, thereby eliminating the expensive pressure sensor while maintaining control accuracy

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/physical pressure sensing system with a thermal measurement system. Instead of using pressure sensors to directly measure refrigerant pressure, the system uses temperature sensors combined with thermodynamic calculations to determine the same control parameter (superheat degree), substituting a cheaper thermal measurement approach for the expensive pressure measurement approach

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If temperature sensors are used instead of pressure sensors, then cost is reduced, but measurement precision may be affected

Engineering Contradiction:

ImprovecostVSAvoidcontrol accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent introduces the superheat degree calculation as an intermediary process that bridges temperature measurements and control decisions. By calculating superheat degree from temperature differences (compressor inlet temperature minus evaporator temperature), the system uses this intermediate parameter to achieve accurate control equivalent to direct pressure sensing

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a computational model that copies the functional behavior of pressure sensing. Instead of directly measuring pressure, the system measures temperatures and computationally derives the same control information, creating a virtual copy of pressure sensor functionality through thermodynamic relationships

Inventive Principle:

Principle #26Copying

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 allows for precise control of the valve opening degree using temperature sensors, reducing the overall cost of the electronic expansion valve and maintaining high control accuracy, thereby facilitating wider application in heat exchange systems.

Implementation Method 1

a first temperature sensor configured to detect an evaporator temperature Teva; a second temperature sensor configured to detect a compressor inlet temperature T suc ; a third temperature sensor configured to detect a compressor outlet temperature T dis ; a fourth temperature sensor configured to detect a condenser temperature T con

Methodology Applied

Scientific EffectTemperature detection:

Data Source

PatentEP3719418A1Electronic expansion valve, heat exchange system and method for controlling electronic expansion valve

Publication Date: 2020.10.07 CARRIER CORP

Figure 1~2
Figure 3

AI summary

The present disclosure provides an electronic expansion valve (3), a heat exchange system, and a control for controlling an electronic expansion valve. The electronic expansion valve includes: a valve body (30); a first temperature sensor (321) configured to detect an evaporator temperature Teva; a second temperature sensor (322) configured to detect a compressor inlet temperature Tsuc; a third temperature sensor (323) configured to detect a compressor outlet temperature Tdis; a fourth temperature sensor (324) configured to detect a condenser temperature Tcon; and a controller (31), which is associated with the first temperature sensor, the second temperature sensor, the third temperature sensor and the fourth temperature sensor, and which adjusts an opening degree of the valve body based on temperature signals from the first temperature sensor, the second temperature sensor, the third temperature sensor and the fourth temperature sensor. The electronic expansion valve according to the present disclosure is applicable to various operating conditions.