Low-Pressure EGR Line Second Particulate Filter
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Solution Overview
Problem
Internal combustion engines with diesel particulate filters in the exhaust-gas tract face issues with flow resistance and the inability to have two filters in series due to the need for unfiltered exhaust-gas flow in the EGR system, which can lead to damage to the exhaust-gas turbocharger and clogging of particulate filters.
Innovation Solution
Incorporating a second particulate filter in the low-pressure exhaust-gas recirculation line with a filter mesh size of at least 50 μm to allow smaller particles to pass while holding back larger ones, protecting the turbocharger and preventing filter clogging, and using materials like wire mesh, screen, or sintered materials for this filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diesel particulate filter is installed in the exhaust-gas tract to filter soot particles, then the exhaust-gas is cleaned, but the filter creates flow resistance and cannot be placed in series with another filter due to the need for unfiltered flow in the EGR system
Solution Approach 1:
The patent divides the filtering function into two separate systems: a first particulate filter (diesel particulate filter) in the exhaust-gas tract for cleaning exhaust-gas, and a second particulate filter in the low-pressure EGR line for protecting the compressor. This segmentation allows each filter to perform its specific function without creating excessive flow resistance in a single series configuration.
Solution Approach 2:
The low-pressure EGR line acts as an intermediary pathway that extracts exhaust-gas downstream of the first particulate filter and delivers it to the compressor through the second particulate filter. This intermediary system enables selective filtering where the second filter protects the compressor from larger particles while allowing smaller filtered particles to pass.
2Productivity
If exhaust-gas flows unfiltered through the exhaust-gas tract to avoid flow resistance, then flow resistance is minimized, but particles can damage the exhaust-gas turbocharger and clog particulate filters
Solution Approach 1:
The second particulate filter is installed in advance in the low-pressure EGR line to prevent particles from reaching and damaging the compressor. This preliminary protective action ensures that the compressor is protected before particles can cause harm, while still allowing the majority of exhaust-gas to flow through the main tract without restriction.
Solution Approach 2:
The patent applies different filtering qualities at different locations: the first particulate filter provides fine filtering for exhaust-gas cleaning in the main tract, while the second particulate filter provides coarse filtering specifically at the compressor inlet to protect against particle damage. Each location receives the appropriate filtering quality needed for its function.
3Reliability
If a second particulate filter with fine mesh size is installed in the low-pressure EGR line to protect the compressor, then compressor protection is improved, but the filter will clog and require replacement
Solution Approach 1:
The second particulate filter uses a mesh size of at least 50 μm, which is coarser than the first particulate filter. This parameter change allows the filter to protect the compressor from damaging particles while permitting smaller particles to pass through, preventing clogging and extending the filter's service life throughout the engine's operational lifetime.
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
This configuration ensures the compressor's protection from damaging particles, maintains filter throughput, and prevents clogging, ensuring operational reliability and minimizing pressure loss in the low-pressure exhaust-gas recirculation line over the engine's lifetime.
Implementation Method 1
a second particulate filter (56) is disposed in the low-pressure exhaust-gas recirculation line (44), wherein the second particulate filter (56) has a filter mesh size of at least 50 μm such that the second particulate filter (56) allows particles with a diameter of less than the filter mesh size to pass and holds back particles with a diameter of at least the filter mesh size
Implementation Method 2
an exhaust-gas recirculation cooler (50) is disposed in the low-pressure exhaust-gas recirculation line (44)
Data Source
AI summary
An internal combustion engine includes an exhaust-gas tract and a supply system for combustion air. A compressor of an exhaust-gas turbocharger is disposed in the supply system for combustion air. A turbine of the exhaust-gas turbocharger, a first particulate filter, and an adjustable exhaust-gas throttle are disposed in series in a downstream direction in the exhaust-gas tract. A low-pressure exhaust-gas recirculation line branches off from the exhaust-gas tract downstream of the first particulate filter and discharges into the supply system for combustion air upstream of the compressor. An exhaust-gas recirculation cooler, an exhaust-gas recirculation valve, and a second particulate filter with a filter mesh size of at least 50 μm are disposed in the low-pressure exhaust-gas recirculation line.