Sealed Test Fixture for Engine Exhaust Particulate Collection
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Solution Overview
Problem
Existing test fixtures for collecting particulate matter from engine exhaust gases are cumbersome, time-consuming to connect, and require special handling to prevent burn injuries and contamination, lacking a sealable and easily accessible filter containment system.
Innovation Solution
A test fixture with transverse mounting plates and guide rods allows for preinstallation and easy removal of filter cartridges without connecting to the testing system, featuring a sealed filter containment mechanism that eliminates the need for extensive cooling or special handling tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a clamshell or hinged holder is used to house the filter cartridge, then the filter can be contained during testing, but the fixture becomes cumbersome and time-consuming to connect and disconnect from the testing system
Solution Approach 1:
The fixture is divided into separate modular components: a stationary housing with mounting plates and guide rods, and a movable second mounting plate that can be independently positioned. This segmentation allows the filter cartridge to be accessed and replaced without moving or disconnecting the entire fixture from the testing system, reducing connection/disconnection time while maintaining reliable containment during operation
Solution Approach 2:
The filter cartridge is pre-installed in the first mounting plate before the testing begins. The second mounting plate is then moved to the closed position to seal the containment chamber. This preliminary installation allows the filter to be ready for testing without requiring fixture reconfiguration, and the sealable design enables quick opening for filter replacement without system disconnection
2Measurement precision
If the test fixture is heated to elevated temperature (e.g., 47°C) to maintain test conditions, then accurate particulate matter collection is achieved, but special handling tools and extreme caution are required to prevent burn injuries
Solution Approach 1:
The filter cartridge is nested within a sealed containment chamber formed by the first and second mounting plates. This nested design allows the filter to be installed and sealed while the fixture is at elevated temperature, and the sealed chamber isolates the hot surfaces from direct contact during filter handling. The filter can be replaced without exposing handlers to hot surfaces, eliminating the need for special cooling procedures or protective handling tools
3Object-affected harmful factors
If gloves are used when handling the test cartridge, then burn protection is provided, but contamination of the sample media occurs
Solution Approach 1:
The filter cartridge is nested within a sealed containment chamber that can be opened to provide direct access to the filter. This design allows handlers to wear clean gloves or use clean tools when installing or removing the filter cartridge, while the sealed chamber prevents contamination during the critical phases of filter installation and removal. The containment structure itself acts as a barrier against contamination
4Ease of operation
If the exhaust gas flow is diluted with air to reduce temperature, then the test fixture can be handled more safely, but the flow stream temperature reduction may affect test accuracy
Solution Approach 1:
The filter cartridge is nested within an insulated or thermally controlled containment chamber that maintains the required test temperature without requiring extensive air dilution. This sealed environment allows the exhaust gas to be heated to the precise test temperature (e.g., 47°C) and maintained throughout the test, while the containment structure prevents excessive heat transfer to external surfaces, allowing safe handling without compromising temperature accuracy
Data Source
AI summary
A test fixture for collecting particulate matter carried in the exhaust gas stream of an engine has a pair of coaxially aligned mounting plates, each having a filter cartridge holder mounted thereon. One of the mounting plates is moveable with respect to the other along a predefined longitudinal axis of the test fixture between an open position, whereat a filter cartridge is easily placed or removed, and a closed position at which a filter media mounted in the filter cartridge is sealed during a prescribed test sequence. An actuator mounted on a third coaxially aligned mounting plate has an extendable rod connected to the second mounting plate to effect movement of the second mounting plate between the open an closed positions.