Injector Solenoid Valve Closing Time via Logarithmic Coil Voltage
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Solution Overview
Problem
Existing methods for determining the closing time of a solenoid valve in injectors suffer from low signal-to-noise ratios and require complex filtering or measurement techniques due to injector tolerances, leading to uneven fuel distribution.
Innovation Solution
Determine the closing time of a solenoid valve by evaluating the logarithmic voltage ratio between the coil voltage and a reference value, using the second derivative of this ratio to identify the inflection point, and employing moving averages to smooth the signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the second derivative of the voltage signal is used to identify the inflection point, then the closing time can be determined, but the signal-to-noise ratio becomes very low requiring strong filtering or sophisticated measurement techniques
Solution Approach 1:
The patent transforms the voltage signal through mathematical operations (integration and logarithmic transformation) to change its parameters. By integrating the voltage signal once and then taking the logarithm, the inflection point becomes a maximum point that is easier to detect with higher signal-to-noise ratio, avoiding the need for second derivative calculations
Solution Approach 2:
The patent replaces complex measurement techniques and strong filtering requirements with a mathematical transformation approach. Instead of using sophisticated hardware measurement techniques to handle low signal-to-noise ratio, the solution uses signal transformation to convert the detection problem into finding a maximum point in the transformed signal
2Measurement precision
If strong filtering is applied to improve signal-to-noise ratio, then measurement accuracy improves, but the complexity of the measurement system increases
Solution Approach 1:
The patent replaces complex physical filtering systems with mathematical signal transformation. By integrating the voltage signal and applying logarithmic transformation, the method converts noise-sensitive second derivative detection into maximum point detection in a transformed domain, eliminating the need for complex filtering hardware or algorithms
3Ease of manufacture
If injector tolerances are not compensated, then the system is simpler, but uneven fuel distribution occurs
Solution Approach 1:
The patent implements a feedback mechanism by measuring the actual closing time of each injector through voltage signal analysis and using this information to compensate for individual injector tolerances. The method determines the closing time by detecting the maximum point in the integrated and logarithmically transformed voltage signal, providing feedback data that can be used to adjust injection duration and achieve uniform fuel distribution across all injectors
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
Improves the signal-to-noise ratio and enables a robust, computationally efficient determination of the closing time, reducing measurement inaccuracies and ensuring precise fuel injection.
Implementation Method 1
The injector has a coil to generate a magnetic field, allowing the coil to function as an electromagnet
Implementation Method 2
The induced voltage is generated by decaying eddy currents in a magnetic circuit of the coil actuator and by movement of the magnetic armature relative to the coil
Implementation Method 3
The induced voltage is generated by decaying eddy currents in a magnetic circuit of the coil actuator
Data Source
Figure 1a~1b
Figure 2
Figure 3
AI summary
The invention relates to a method for determining a closing time of a solenoid valve of an injector, wherein the closing time is determined by ascertaining a logarithmic voltage ratio between a coil voltage and a reference value for the coil voltage, the coil voltage being a voltage applied to a coil of the solenoid valve.