System for monitoring the position of a valve needle of an expansion valve
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Solution Overview
Problem
Existing methods for determining the position of the valve needle in expansion valves are imprecise and error-prone, requiring a reference run upon startup, which is complex and prone to system-related inaccuracies.
Innovation Solution
A system that includes a magnet fixed to the valve needle and a Hall sensor attached to the valve seat, using the flux density vector to directly determine the absolute axial position of the valve needle, eliminating the need for a reference run and minimizing the influence of temperature variations, radiation fields, and manufacturing tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods are used to determine valve needle position, then the system can operate without additional components, but the measurement precision is low and a reference run is required
Solution Approach 1:
The patent replaces conventional mechanical position detection methods with a magnetic field-based Hall sensor system. The Hall sensor detects the position of the valve needle through magnetic flux density changes from an attached magnet, eliminating the need for mechanical reference runs and improving measurement precision without significantly increasing system complexity
Solution Approach 2:
The patent introduces a magnet as an intermediary element attached to the valve needle. This magnet serves as a mediator that translates the mechanical position of the needle into detectable magnetic field changes, allowing the Hall sensor to accurately determine needle position without direct mechanical contact or complex reference procedures
2Ease of operation
If a reference run is performed to detect current valve needle position, then the position can be determined, but the process becomes complex and time-consuming
Solution Approach 1:
The Hall sensor continuously monitors the magnetic field position of the valve needle from startup, eliminating the need for preliminary reference runs. The system is configured to detect absolute position immediately, allowing direct operation without time-consuming calibration procedures
Solution Approach 2:
The magnetic field-based detection system automatically determines valve needle position without requiring external reference procedures or manual calibration. The Hall sensor continuously self-monitors the magnet position, providing automatic position detection that eliminates complex startup sequences
3Reliability
If conventional position detection is used, then the system structure remains simple, but the accuracy is affected by temperature variations and manufacturing tolerances
Solution Approach 1:
The patent replaces temperature-sensitive mechanical position detection with a magnetic field-based Hall sensor system. Magnetic field measurements are less affected by temperature variations and manufacturing tolerances compared to mechanical encoders or potentiometers, improving reliability while reducing sensitivity to environmental factors
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 achieves high accuracy in determining the valve needle position directly, reducing the need for a reference run and minimizing errors from temperature, radiation, and manufacturing variations, particularly beneficial in the automotive sector.
Implementation Method 1
a Hall sensor, wherein the Hall sensor is fixedly assigned to the valve seat and, by means of a flux density vector of the magnet, is configured for determining directly the absolute axial position of the valve needle
Data Source
AI summary
The invention relates to a system for monitoring the position of the valve needle of an expansion valve, having an expansion valve having a valve seat; a valve needle which is configured so as to be convertible axially between a first position in which the valve needle is received by the valve seat and closes the expansion valve, and a second position in which the valve needle is axially spaced apart from the valve seat and the expansion valve is at least partially opened; wherein the expansion valve has a magnet which is fixedly assigned to the valve needle such that the magnet is axially movable conjointly with the valve needle; and has a Hall sensor, wherein the Hall sensor is fixedly assigned to the valve seat and, by means of the flux density vector of the magnet, is configured for determining directly the absolute axial position of the valve needle. The invention moreover relates to a system for calculating the axial position of a valve needle in an expansion valve according to one of the embodiments described, wherein the system, by means of the Hall sensor, is configured for detecting a first component of the flux density vector of the magnet, by means of the Hall sensor is configured for detecting a second component of the flux density vector of the magnet, and for calculating therefrom the absolute axial position of the valve needle.