Exhaust Gas Analysis Device With CO2-Based Moisture Correction
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Solution Overview
Problem
Existing exhaust gas analysis systems face challenges in accurately correcting measurement errors caused by moisture without using a separate moisture concentration meter, which is cumbersome and costly.
Innovation Solution
An exhaust gas analysis device that estimates moisture concentration using a CO2 concentration and hydrogen/carbon ratio of the fuel, allowing for correction of measured component concentrations without a moisture meter, employing a first analyzer for wet measurement and a second analyzer for dry CO2 measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a moisture concentration meter is used to measure moisture concentration in exhaust gas, then measurement precision of moisture is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses CO2 concentration as an intermediary parameter to indirectly determine moisture concentration. Instead of directly measuring moisture with a complex moisture concentration meter, the system measures CO2 concentration (which is easier to measure accurately) and uses it as a mediator to calculate moisture concentration through the established relationship between CO2 and H2O from fuel combustion.
Solution Approach 2:
The system uses the CO2 measurement data that is already being collected for exhaust gas analysis to simultaneously determine moisture concentration. The existing CO2 analyzer serves dual purposes: measuring CO2 for emissions analysis and providing data for moisture concentration calculation, eliminating the need for a separate moisture measurement device.
2Measurement precision
If a moisture concentration meter is used to correct measurement errors, then measurement precision of exhaust gas components is improved, but cost increases
Solution Approach 1:
The existing CO2 analyzer in the exhaust gas analysis system provides data that is used to correct measurement errors caused by moisture. The system essentially pays for itself by utilizing data from an existing instrument (CO2 analyzer) to achieve the correction function that would otherwise require additional expensive equipment.
Solution Approach 2:
CO2 concentration serves as an intermediary that enables cost-effective correction of measurement errors. By measuring CO2 (which is already being done) and using it to infer moisture concentration, the system achieves accurate correction without the high cost of dedicated moisture concentration meters.
3Measurement precision
If calibration is performed using a moisture concentration meter, then measurement precision is improved, but ease of operation deteriorates due to difficulty in preparing gases with various moisture concentrations
Solution Approach 1:
The patent replaces the complex calibration process involving moisture concentration meters with a simpler calibration based on CO2 concentration measurements. Since CO2 concentration can be more easily and accurately controlled and measured during calibration, the intermediary use of CO2 data simplifies the calibration procedure while maintaining or improving accuracy.
Solution Approach 2:
The patent extracts the essential calibration information from the complex moisture measurement domain and transfers it to the CO2 measurement domain. By taking out the critical relationship between fuel composition and exhaust gas composition, and expressing it through CO2 measurements, the system achieves calibration without the operational difficulties of moisture concentration meter calibration.
Data Source
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AI summary
An exhaust gas analysis device (2) analyzes exhaust gas generated when fuel is combusted. This exhaust gas analysis device (2) includes a first analyzer (21) that measures a concentration of a component to be measured in the exhaust gas, a second analyzer (22) that measures a concentration of CO2 in the exhaust gas, a storage portion (233) that stores a hydrogen/carbon ratio, which is a ratio between hydrogen and carbon composing the fuel, or an input receiving portion (230) that receives an input of the hydrogen/carbon ratio, a moisture concentration estimating portion (235) that, based on the measured CO2 concentration and on the hydrogen/carbon ratio of the fuel, estimates a concentration of moisture in the exhaust gas, and a correcting portion (232) that, based on the estimated moisture concentration, corrects the measured concentration of the component to be measured.