Solenoid Valve Opening Time Detection via Current Inflection
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Solution Overview
Problem
Existing methods for monitoring solenoid-actuated valves can only detect when the valve is fully open or closed, failing to accurately determine the time the valve begins to open due to delays in current buildup and lash, making it difficult to pinpoint the duration of valve opening during an energization cycle.
Innovation Solution
A method that involves energizing the solenoid coil to generate a current signature, detecting a first inflection point when the armature starts to move and a second inflection point when it reaches the open position, allowing for the detection of subtle movements and accurate determination of the elapsed opening time by loosely coupling the armature and poppet to create distinct inflection points in the current signature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing monitoring methods are used to detect valve position, then the valve can be determined to be fully open or closed, but the time when the valve begins to open cannot be detected due to delays in current buildup and lash
Solution Approach 1:
The patent replaces mechanical direct coupling between the armature and poppet with a magnetic field-based detection system. By using a magnet attached to the armature and a sensor (such as a Hall effect sensor or reed switch) to detect the magnet's position, the system can sense armature movement without mechanical contact. This substitution allows detection of the exact moment the armature begins to move, eliminating the time loss associated with mechanical lash and enabling precise measurement of valve opening time.
2Loss of information
If the armature and poppet are tightly coupled, then the valve structure is simpler, but subtle movements of the armature between hard stops cannot be detected
Solution Approach 1:
The patent replaces tight mechanical coupling with a magnetic field-based detection system. A magnet is attached to the armature, and a sensor (such as a Hall effect sensor or reed switch) is positioned to detect the magnet's position. This allows the armature to move independently with minimal mechanical constraint while the sensor continuously monitors its position, capturing subtle movements between hard stops without increasing mechanical complexity.
Solution Approach 2:
The patent introduces a magnet as an intermediary between the armature and the detection system. The magnet attached to the armature creates a magnetic field that the sensor can detect, allowing indirect measurement of armature position. This intermediary enables precise detection of armature movement without requiring direct mechanical coupling between the armature and the sensor, thus preserving movement information while avoiding mechanical complexity.
3Force
If current buildup time is required to move the armature, then the solenoid can generate sufficient force, but the delay prevents accurate determination of when the valve cracks open
Solution Approach 1:
The patent replaces force-based indirect measurement with direct position sensing. Instead of inferring armature movement from current buildup and solenoid force characteristics, the system uses a magnet attached to the armature and a sensor to directly detect when the armature begins to move. This allows the solenoid to generate the necessary force without delay, while the magnetic sensing system accurately captures the exact moment the valve cracks open, eliminating the measurement precision problem.
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 approach enables precise monitoring of the valve's opening time, providing valuable information for improved operation and diagnostics in applications like fuel vapor control systems by clearly defining the time the valve is open during an energization cycle.
Implementation Method 1
energizing a coil in the valve to generate a current signature
Implementation Method 2
generate a current signature reflecting current vs. time
Data Source
AI summary
A method for monitoring operation of a solenoid valve having an armature and a poppet coupled to the armature includes the steps of energizing a coil in the valve to generate a current signature reflecting current vs. time, detecting a first inflection point in the current signature, wherein the first inflection point occurs when the armature starts to move from one of the open and closed positions toward the other of the open and closed positions, and detecting a second inflection point in the current signature. The second inflection point occurs when the armature moves completely to the other of the open and closed positions. In one embodiment, the first inflection point indicates when the valve begins to open, making it possible to accurately determine the elapsed opening time of the valve.