Ozone Generator Feedback Control for NOx Exhaust Analysis
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Solution Overview
Problem
Conventional gas analyzers face challenges in reliably measuring nitrogen oxides in exhaust gases due to incomplete conversion of nitrogen monoxide to nitrogen dioxide and excessive ozone production, leading to unwanted nitrogen oxide compounds and incomplete thermal decomposition.
Innovation Solution
A gas analyzer with a regulating device that controls ozone generation based on measured ozone concentration to maintain a setpoint value, using ultraviolet light sources for ozone production from residual oxygen in the exhaust gas, and employing LED arrays with specific wavelengths for precise measurement of nitrogen dioxide and ozone concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ozone is generated with excess to maximize nitrogen monoxide conversion, then conversion efficiency improves, but unwanted nitrogen oxide compounds form and thermal decomposition becomes incomplete
Solution Approach 1:
The patent implements a feedback control system where the actual ozone concentration is continuously measured and compared to a target concentration. The ozone generator is regulated based on this feedback to maintain the optimal ozone level for complete nitrogen monoxide conversion without generating excess ozone that would form unwanted compounds like dinitrogen pentoxide.
Solution Approach 2:
The patent changes the ozone concentration parameter from excessive to precisely controlled levels. By regulating the ozone generator to maintain a specific target concentration rather than using excess ozone, the system achieves complete conversion of nitrogen monoxide to nitrogen dioxide while preventing the formation of unwanted higher nitrogen oxide compounds.
2Adaptability or versatility
If multiple light-emitting diodes with different wavelengths are used for simultaneous measurement, then measurement capability improves, but device complexity increases
Solution Approach 1:
The patent employs multiple light-emitting diodes with different wavelengths (350-500 nm for nitrogen dioxide, 250-265 nm for ozone) that share common optical components including the measuring chamber, detector, and evaluation device. This multi-functional approach enables simultaneous measurement of different gases without requiring separate complete measurement systems, thus improving versatility while controlling complexity.
Solution Approach 2:
The patent merges the measurement paths for nitrogen dioxide and ozone detection by using a single measuring chamber, detector, and evaluation system. Both light-emitting diodes illuminate the same measuring chamber and their signals are processed by the same detector and evaluation device, combining multiple measurement functions into one integrated system.
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
Ensures almost complete conversion of nitrogen monoxide to nitrogen dioxide, reducing excess ozone production and enabling linear measurement of nitrogen oxides with high accuracy and minimal interference, thus providing reliable continuous monitoring with reduced equipment costs.
Implementation Method 1
ozone is generated from oxygen
Implementation Method 2
exhaust gas is treated with the ozone generated to convert nitrogen monoxide contained in the exhaust gas into nitrogen dioxide
Implementation Method 3
a first light-emitting diode that emits with a central wavelength of between 350 nm and 500 nm, a second light-emitting diode that emits with a central wavelength of between 250 nm and 265 nm
Implementation Method 4
the nitrogen dioxide concentration in the treated exhaust gas is measured photometrically using a first light-emitting diode
Data Source
AI summary
Gas analyzer and method for measuring nitrogen oxides in an exhaust gas, wherein to measure the nitrogen oxides, ozone is generated from oxygen, the exhaust gas is treated with the ozone generated to convert nitrogen monoxide within the exhaust gas into nitrogen dioxide, the nitrogen dioxide concentration in the treated exhaust gas is measured photometrically using a first light-emitting diode which emits with a central wavelength between 350 nm and 500 nm and output as the nitrogen oxide concentration in the exhaust gas, and the ozone concentration in the treated exhaust gas is measured photometrically using a second light-emitting diode which emits with a central wavelength between 250 nm and 265 nm, where generation of the ozone using the measured ozone concentration as an actual value is regulated to a prespecified setpoint value to enable reliable continuous measurement of nitrogen oxides in exhaust gases with a low outlay on equipment.