Bent Optical Fiber Urea Sensor for SCR Refractive Index Precision
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Solution Overview
Problem
Existing sensors for monitoring urea solution quality and concentration in automotive SCR systems are inadequate in accurately measuring changes in refractive index due to contaminants and temperature variations, affecting the effectiveness and life expectancy of the urea solution.
Innovation Solution
A sensor system utilizing a bent optical fiber lumen with a light source and detector to measure the concentration and quality of urea solutions by emitting light and determining changes in refractive index based on light transmission and reflection, allowing for precise monitoring and control of urea solution properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a straight optical fiber is used to transmit light through the urea solution, then the sensor structure is simple, but the measurement precision of refractive index changes is insufficient
Solution Approach 1:
The patent applies curvature to the optical fiber by configuring it in a bent or coiled shape rather than a straight line. This curvature increases the interaction length between light and the urea solution, enhancing the sensitivity of refractive index measurements while maintaining a relatively simple overall sensor structure.
Solution Approach 2:
The patent transitions from a one-dimensional straight optical fiber to a two-dimensional or three-dimensional bent configuration. This dimensional change allows the light to traverse a longer path through the solution without increasing the linear footprint of the sensor, thereby improving measurement precision without proportionally increasing device complexity.
2Measurement precision
If the optical fiber is bent into a complex shape to increase light-solution interaction, then the measurement sensitivity improves, but the device complexity increases
Solution Approach 1:
The patent employs moderate curvature in the optical fiber configuration, bending it into manageable shapes that increase interaction length without creating excessive structural complexity. This balanced approach achieves improved measurement sensitivity while keeping the device manufacturable and maintainable.
Solution Approach 2:
The bent optical fiber configuration serves multiple functions: it increases light-solution interaction length for better measurement precision, maintains flexibility for installation in various tank configurations, and provides structural stability. This multi-functionality reduces the need for additional components, thereby limiting the increase in device complexity.
3Measurement precision
If light transmission path is extended to detect smaller refractive index changes, then the measurement precision improves, but the loss of light energy increases
Solution Approach 1:
The bent optical fiber configuration extends the light transmission path through the solution, allowing for more precise detection of refractive index changes. The curvature is optimized to achieve sufficient interaction length while minimizing unnecessary bends that would cause excessive light loss.
Solution Approach 2:
The patent employs periodic modulation of the light source and synchronous detection methods. By modulating the light source at a specific frequency and using synchronous detection, the system can extract weak signal changes from the transmitted light even after extended path length, thereby maintaining measurement precision while compensating for light energy loss.
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 sensor system effectively measures urea solution concentration and quality by detecting changes in refractive index, enabling optimal operation and longevity of SCR systems by providing accurate data for emissions control.
Implementation Method 1
a bent optical fiber lumen with a light source and detector to measure the concentration and quality of urea solutions by emitting light and determining changes in refractive index based on light transmission and reflection
Implementation Method 2
determining changes in refractive index based on light transmission and reflection
Data Source
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AI summary
A sensor (100) to measure a liquid (120), such as an urea solution. The sensor (100) includes a light source (132) operably coupled to a lumen (136) disposed in a liquid solution (120), the light source (132) configured to emit light and communicate the light to the lumen (136); a light detector (134) operably coupled to the lumen (136), the light detector (134) configured to receive at least a portion of the light from the lumen (136); and a controller (140) configured to determine a concentration or quality of the liquid solution (120) based on the light emitted by the light source (132) and the portion of light received by the light detector (134).