Optical Urea Sensor Refraction Interface
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Solution Overview
Problem
Existing SCR systems face challenges in precisely controlling the quality and concentration of the aqueous urea solution in storage tanks, which is crucial for effective NOx reduction in vehicle emissions, due to the need for precise dosing and quality of the reducing agent.
Innovation Solution
A device comprising a light source, photodetector, and a refractive material allows for the monitoring of urea solution concentration by varying light beam intensity and angle, enabling quick and precise detection of urea presence and concentration without moving parts, using a light emitting diode and photodiode for efficient energy use and chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light source and photodetector are used to monitor urea concentration, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The optical system is divided into separate functional modules: light source module, optical path module with refraction interface, and photodetector module. This segmentation allows each component to be optimized independently while maintaining overall system precision for urea concentration measurement.
Solution Approach 2:
A refraction interface element is introduced as an intermediary between the light source and photodetector. This intermediary component enables precise concentration measurement through refractive index changes while keeping the overall device structure relatively simple by using a passive optical element rather than complex active sensing mechanisms.
2Reliability
If temperature measurement and adjustment are added, then reliability is improved, but device complexity increases
Solution Approach 1:
A temperature sensor is integrated into the optical system to provide real-time temperature feedback. This feedback mechanism allows the system to compensate for temperature-induced refractive index changes, improving measurement reliability without requiring complex external control systems.
Solution Approach 2:
The optical system is designed to serve multiple functions: primary urea concentration measurement through refraction, and secondary temperature monitoring through the same optical path. This multi-functionality reduces overall device complexity by combining multiple sensing capabilities into a single integrated platform.
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 solution provides a simple, compact, and reliable method to check if the tank is empty and ensures the correct urea concentration, preventing engine malfunction and ensuring compliance with emission regulations by integrating temperature measurement and adjustment for precise control.
Implementation Method 1
a light beam emitted by the light source is propagated by the face of the part, by refraction, towards the photodetector, the light source being arranged so that the propagated light beam has an angle which varies according to the urea concentration
Implementation Method 2
a photodetector capable in detecting a part of a light beam emitted by the light source
Data Source
Figure 1~3
AI summary
The invention relates to a device (18) for monitoring a urea solution (14) in a tank (12) of a motor vehicle (10). Said device includes a light source (24) suitable for emitting a light beam, a photodetector (26) configured to detect a portion of a light beam emitted by the light source (24), and a component (22) made of a material enabling the propagation of a light beam emitted by the light source (24). The component (22) further has a surface (28) which is to contact the urea solution (14). The light source (24), the photodetector (26), and the component (22) are arranged such that a light beam emitted by the light source (24) is propagated through the surface (28) of the component (22), by reflection or by refraction, toward the photodetector (26). The invention further relates to a tank including such a monitoring device, as well as to a method for monitoring the urea solution.