Exhaust Gas PM Sampling with Split Flow Ratio Weighting
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Solution Overview
Problem
Existing exhaust gas analysis systems face challenges in accurately measuring particulate matter (PM) due to time-consuming filter replacement and low PM collection amounts, especially with reduced PM concentrations, necessitating a solution that allows continuous measurement without filter replacement.
Innovation Solution
An exhaust gas analysis apparatus with a split flow ratio control mechanism that adjusts the ratio of sampling exhaust gas to total exhaust gas flow, enabling accurate PM measurement by changing the split flow ratio based on vehicle driving modes and regulatory weighting factors without replacing filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If filter replacement is performed between adjacent phase intervals to implement weighting, then measurement accuracy is maintained, but measurement time increases and productivity decreases
Solution Approach 1:
The invention introduces a bypass flow path that allows a portion of the diluted exhaust gas to bypass the filter before collection. This preliminary diversion of flow enables the system to implement weighting factors without requiring filter replacement, as the bypass mechanism can be dynamically adjusted during different phase intervals to achieve the required weighting while continuously collecting PM on the same filter.
2Productivity
If filter replacement is avoided to improve productivity, then measurement efficiency increases, but measurement precision deteriorates due to insufficient PM collection amount
Solution Approach 1:
The invention employs a dynamic bypass flow ratio control mechanism that can adjust the bypass flow ratio during different phase intervals. By dynamically changing the bypass flow ratio, the system optimizes the amount of exhaust gas directed to the filter for collection while maintaining the ability to implement weighting factors. This dynamic adjustment ensures sufficient PM collection amount for accurate measurement while avoiding filter replacement, thus maintaining both precision and productivity.
3Reliability
If PM concentration is reduced in exhaust gas, then emission standards are met, but measurement precision deteriorates due to insufficient PM collection amount
Solution Approach 1:
The invention changes the parameter of bypass flow ratio to optimize PM collection. By adjusting the bypass flow ratio, the system increases the proportion of exhaust gas that passes through the filter for PM collection. This parameter change compensates for the reduced PM concentration in compliant exhaust gas, ensuring sufficient PM collection amount for accurate measurement while maintaining emission standard compliance.
4Ease of operation
If bypass flow path is introduced to enable continuous measurement, then device complexity increases, but ease of operation improves
Solution Approach 1:
The invention segments the exhaust gas flow into two separate paths: a main flow path that passes through the filter for PM collection, and a bypass flow path that diverts a portion of the flow around the filter. This segmentation is achieved through a bypass flow path with a controllable bypass flow ratio. By dividing the flow paths in this manner, the system enables continuous measurement with filter weighting capability, improving ease of operation while managing device complexity through a relatively simple bypass configuration.
Data Source
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AI summary
In order to provide an exhaust gas analysis apparatus that, without the need to greatly change the flow rate of diluted exhaust gas passing through a filter, for example, when switching a driving mode, can change the flow rate of exhaust gas in the diluted exhaust gas passing through the filter with good followability to reflect weighting, and accurately measure PM, the exhaust gas analysis apparatus is adapted to include: a collection part that collects particulate matter in sampling exhaust gas partially splitting from original exhaust gas or in the diluted exhaust gas resulting from diluting the sampling exhaust gas with diluent gas; and a split flow ratio control mechanism configured to, in accordance with a vehicle driving mode set in compliance with predetermined regulations, change a split flow ratio that is the ratio of the split flow rate of the sampling exhaust gas to the total flow rate of the original exhaust gas.