Exhaust Gas Analyzer O2 Calculation via CO2 and EGR Rate
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Solution Overview
Problem
Conventional FTIR analyzers cannot measure oxygen (O2) concentration in exhaust gas since O2 does not absorb infrared light, requiring a separate O2 meter, resulting in a large and costly exhaust gas analyzer system.
Innovation Solution
An exhaust gas analyzer that uses an infrared light source, photodetector, CO2 concentration calculation, and O2 concentration calculation part, which calculates O2 concentration using a fuel combustion reaction equation and EGR rate, allowing for O2 measurement without a separate O2 meter, and incorporating machine learning for accurate calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate O2 meter is used to measure oxygen concentration, then measurement accuracy is improved, but device size and cost increase
Solution Approach 1:
The patent combines the O2 measurement function with the existing FTIR analyzer by integrating an O2 concentration calculation unit that uses the combustion reaction equation. This merging eliminates the need for a separate O2 meter while maintaining measurement capability through mathematical calculation based on CO2 concentration and combustion stoichiometry.
Solution Approach 2:
The patent introduces a calculation-based intermediary approach where O2 concentration is not measured directly but derived through mathematical relationships. The O2 concentration calculation unit acts as an intermediary that computes O2 levels using the combustion reaction equation, converting measurable parameters (CO2 concentration, fuel composition) into the desired O2 concentration value.
2Productivity
If FTIR analyzer is used to analyze exhaust gas components, then simultaneous analysis of multiple components is improved, but O2 measurement capability deteriorates
Solution Approach 1:
The patent makes the FTIR analyzer universal by enabling it to perform both traditional infrared-absorbing component analysis and O2 concentration measurement through the integrated calculation unit. The analyzer now serves multiple functions: direct infrared spectroscopy for CO, CO2, NOx, and calculated O2 concentration through the combustion reaction equation approach.
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
Enables the measurement of O2 concentration without a separate O2 meter, reducing the size and cost of the analyzer while ensuring accurate calculations, and allowing for analysis in both internal combustion engines with and without exhaust gas recirculation systems.
Implementation Method 1
An FTIR analyzer using Fourier transform infrared spectroscopy (FTIR) as described in Patent Document 1 has conventionally been used as one which analyzes components contained in exhaust gas. The infrared light source irradiates infrared light to the exhaust gas. The photodetector detects infrared light after passing through the exhaust gas.
Data Source
AI summary
An exhaust gas analyzer to analyze exhaust gas discharged from an internal combustion engine includes an infrared light source, a photodetector, a CO2 concentration calculation part and an O2 concentration calculation part. The infrared light source irradiates infrared light to the exhaust gas. The photodetector detects infrared light after passing through the exhaust gas. The CO2 concentration calculation part calculates a CO2 concentration in the exhaust gas on the basis of a detection signal obtained by the photodetector. The O2 concentration calculation part calculates an O2 concentration in the exhaust gas from the CO2 concentration by using a fuel combustion reaction equation and an EGR rate in an exhaust gas recirculation system or a value related to the EGR rate.