Optical Injection Valve Characterization via Spray Imaging
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Solution Overview
Problem
Existing methods for characterizing the injection behavior of injection valves, such as common rail injectors, face challenges in accurately measuring injection rates due to interference from natural vibrations in the measuring chamber, requiring complex pressure sensor signal conditioning.
Innovation Solution
The method involves injecting liquid through an injection valve into a measuring chamber, irradiating light onto the spray pattern, detecting and scanning jet images, and evaluating spatially resolved intensity distributions to determine the injection behavior, which is insensitive to natural vibrations and allows clear identification of the injection process's start and end.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensor signal conditioning with low-pass filtering is used to measure injection rate, then measurement of injection parameters is possible, but measurement accuracy deteriorates due to interference from natural vibrations of the measuring chamber
Solution Approach 1:
The patent replaces the mechanical pressure sensor measurement system with an optical measurement system. Instead of using pressure sensors that require low-pass filtering and are affected by mechanical vibrations, the invention uses a laser sheet to illuminate the spray and a camera to capture images of the cavitation structure. This optical approach eliminates the harmful effects of mechanical vibrations and provides direct visualization of the injection process without signal conditioning requirements.
Solution Approach 2:
The patent utilizes optical properties and light reflection to detect spray characteristics. By illuminating the spray with a laser sheet and capturing the reflected or scattered light with a camera, the system converts physical spray characteristics into optical signals (intensity distributions in images) that can be analyzed without being affected by mechanical vibrations in the measuring chamber.
2Measurement precision
If complex pressure sensor signal conditioning is implemented to compensate for vibrations, then injection parameters can be measured, but device complexity increases
Solution Approach 1:
The patent replaces the complex mechanical signal conditioning system with a straightforward optical measurement system. Instead of requiring low-pass filters, amplifiers, and other signal processing components, the invention uses a laser sheet source and a camera to directly capture spray information, significantly simplifying the overall measurement device while maintaining or improving measurement capability.
Solution Approach 2:
The patent creates an optical copy or representation of the spray process through imaging. By capturing images of the cavitation structure and spray pattern, the system obtains a visual replica of the injection process that can be analyzed directly from intensity distributions, eliminating the need for complex intermediate signal processing steps.
3Object-affected harmful factors
If optical measurement of spray patterns is used, then insensitivity to natural vibrations is achieved, but implementation complexity increases
Solution Approach 1:
The patent changes the measurement parameter from pressure (mechanical domain) to light intensity (optical domain). By measuring the intensity distribution in images of the spray and cavitation structure rather than pressure signals, the system achieves vibration insensitivity. The optical parameters (light intensity, pattern geometry) are inherently unaffected by mechanical vibrations in the measuring chamber.
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 provides quantitative and easy-to-implement results, enabling precise characterization of injection behavior with improved accuracy by correlating optical and hydraulic measurement data, reducing measurement artifacts from low-pass filtering.
Implementation Method 1
detecting and scanning temporally successive jet images which are emitted from interfaces of the liquid ejected from the injection valve The light reflected from the spray pattern and imaged onto a recording device
Implementation Method 2
during the injection process into the measuring chamber filled with the liquid medium, cavitation manifests itself as a spray pattern
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
The invention relates to a method and to a device for characterizing the injection behavior of an injection valve (15) for liquids, which method comprises the method steps of injecting liquid into a measurement chamber (11) by means of the injection valve (15), radiating light into the measurement chamber (11) onto liquid discharged from the injection valve (15) as a spray pattern (18), detecting and scanning temporally successive spray images which are produced by light reflected at the spray pattern (18) discharged from the injection valve (15) and are imaged at a capturing apparatus (12) in order to obtain spatially resolved intensity distributions, evaluating the intensity distributions associated with the detected and scanned spray images, wherein those image matrix elements that contain image information associated with the imaged spray pattern (18) are identified in the intensity distributions, and a measure of the injection behavior is determined on the basis of the identified image matrix elements and the time development thereof.