Flexible Filter Test Device for In-Situ Permeability Measurement
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Solution Overview
Problem
Existing devices for measuring the permeability of gas- and liquid-permeable filters or catalytic converters in vehicle exhaust systems are cumbersome, require removal for testing, provide inaccurate results, and can only measure the entire cross-section, failing to identify specific problem areas effectively.
Innovation Solution
A compact, flexible test device with a pressure sensor and control unit that allows for variable overpressure and mass flow adjustments, enabling precise measurement of filter or catalytic converter permeability directly in the exhaust system, even in hard-to-reach areas, by using a sealable housing and a compressed air line for controlled air supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If known devices are used to measure filter permeability, then the entire filter cross-section can be checked, but the device structure becomes voluminous and complex
Solution Approach 1:
The invention divides the filter assessment into segmental measurements across multiple cross-sections rather than requiring a single comprehensive measurement of the entire filter. By taking measurements at different positions (inlet, intermediate, outlet sections), the complex problem of assessing the whole filter is broken down into manageable segments that can be measured with a simpler, more compact device.
Solution Approach 2:
The invention extracts the essential measurement function from complex voluminous testing equipment. Instead of using a large device that checks the entire filter cross-section at once, the solution extracts the core permeability measurement capability and implements it in a compact form that can be positioned at specific locations along the filter.
2Measurement precision
If the filter is removed from the exhaust tract for testing, then accurate measurement can be performed, but costly removal and installation is required
Solution Approach 1:
The invention enables the filter to be tested while remaining in its installed position, allowing the filter to continue serving its exhaust cleaning function during the measurement process. The measurement device is designed to interface with the filter in-situ, eliminating the need for removal and enabling continuous operation during maintenance checks.
3Measurement precision
If known devices measure the entire filter cross-section, then overall permeability can be assessed, but individual problem areas cannot be identified
Solution Approach 1:
The invention segments the filter into multiple measurement zones (inlet section, intermediate sections, outlet section) and performs permeability measurements at each segment. This segmentation preserves local information about contamination patterns, allowing identification of specific problem areas such as blocked inlet channels or outlet issues, rather than providing only an averaged overall assessment.
4Measurement precision
If pressure sensors are used in the exhaust gas flow, then back pressure can be tracked, but measurement results are inaccurate due to uneven flow
Solution Approach 1:
The invention introduces a controlled test medium (gas or liquid) as an intermediary to perform measurements under controlled, uniform flow conditions. Rather than measuring directly in the complex, uneven exhaust gas flow, the test medium provides a stable, controllable environment that eliminates flow irregularities and enables accurate, reliable permeability measurements.
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 accurate, segment-by-segment assessment of filter or catalytic converter permeability and homogeneity, reducing the need for costly removal and improving measurement precision, allowing for timely maintenance and identification of contamination levels.
Implementation Method 1
measuring a pressure difference with a pressure sensor across the filter or catalytic converter
Implementation Method 2
supplying air with a predetermined, variably adjustable volume or mass flow rate at a overpressure of 0.1 bar to 0.6 bar
Data Source
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AI summary
The invention relates to a test device (1) for measurement of a permeability and/or homogeneity of a gas- and/or liquid-permeable filter (14) or catalyst, especially of a filter (14) or catalyst in an exhaust section of a motor vehicle. According to the invention, an optionally flexible housing (2) with a first gas- and/or liquid-permeable end (3) and a second end (4) and at least one pressure sensor (5) arranged within the housing (2) and at least one regulating device (6) are provided, the regulating device (6) being useable to transport air and/or a liquid with a variable volume or mass flow rate or elevated pressure to the first end (3) of the housing (2) and/or away from it with variable volume or mass flow rate or elevated pressure. An inventive test device (1) in a simple design can be used to accurately determine a permeability and/or homogeneity of the filter (14). The invention further relates to a method for measuring a permeability and/or homogeneity of a gas- and/or liquid-permeable filter (14) or catalyst.