Particle Separator Using Differing Flow Regions for Exhaust Gas
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Solution Overview
Problem
Existing particle separators for internal combustion engine exhaust gases are inefficient in removing all sizes of particles, particularly fine and larger particles, due to high exhaust gas counter pressure, frequent filter replacement, and incomplete oxidation, leading to clogging and increased fuel consumption.
Innovation Solution
A particle separator with differing flow regions that utilize both diffusion and mass moment of inertia to separate particles, featuring flow channels with varying cross-sections and deflection mechanisms to ensure the removal of fine and coarse particles, and catalytic oxidation using NO2, with particle collection devices like blind-end bores for efficient particle storage and oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a particle filter is used to separate carbon particles, then particle separation is achieved, but exhaust gas counter pressure increases significantly
Solution Approach 1:
The invention extracts the harmful function of the filter (causing counter pressure) while retaining the useful function (particle separation). By removing the filter and replacing it with a particle separator that uses thermophoresis, convection, or diffusion, the system achieves particle separation without the pressure loss inherent in filter-based systems.
Solution Approach 2:
The invention replaces the mechanical filtration system with a field-based separation system. Instead of using physical filtration media that create resistance, the system uses thermophoretic forces, convective currents, or diffusion processes to separate particles, thereby eliminating the mechanical pressure drop associated with filters.
2Reliability
If a particle filter is used to separate particles, then particle removal is achieved, but non-combustible constituents deposit on the filter causing continuous pressure increase
Solution Approach 1:
The invention extracts the filter component that accumulates deposits and replaces it with a particle separator. The separator allows exhaust gas to flow through continuously without accumulating non-combustible constituents, eliminating the need for frequent replacement and maintaining consistent performance over time.
Solution Approach 2:
The particle separator system is designed to prevent deposit accumulation through its separation mechanism. By using thermophoresis, convection, or diffusion to remove particles before they can form problematic deposits, the system maintains its separation capability without requiring maintenance or replacement, effectively serving itself indefinitely.
3Reliability
If particle separation by diffusion is used in flow dead zones, then very fine particles are removed, but larger particles cannot be separated effectively
Solution Approach 1:
The invention applies different separation mechanisms to different particle size ranges within the exhaust stream. By creating zones with different flow conditions (e.g., high-velocity regions for inertial separation of coarse particles, low-velocity dead zones for diffusion separation of fine particles), the system achieves effective separation across the entire particle size spectrum rather than optimizing for a single size range.
Solution Approach 2:
The particle separator is divided into multiple functional zones or regions, each optimized for separating particles of specific size ranges. This segmentation allows simultaneous operation of different separation mechanisms (inertial, thermophoretic, convective, diffusive) to handle the full spectrum of particle sizes present in diesel exhaust.
4Reliability
If insufficient oxidation occurs in the particle separator, then particles accumulate as coating, but this leads to filter clogging
Solution Approach 1:
The invention ensures continuous and complete oxidation of separated particles through adequate retention time and proper NO2 concentration maintenance. By designing the separator to provide sufficient residence time for oxidation reactions to complete, and ensuring continuous supply of oxidizing agent (NO2), the system prevents accumulation of unoxidized particles that would form clogging coatings.
Solution Approach 2:
The system incorporates feedback mechanisms to monitor and maintain optimal oxidation conditions. By tracking parameters such as NO2 concentration, temperature, and retention time, the system can adjust operating conditions to ensure complete particle oxidation, preventing the formation of harmful soot coatings and maintaining separator performance.
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
Effectively removes all particle sizes from the exhaust gas stream, reducing fuel consumption, minimizing filter replacement, and ensuring complete oxidation of particles, thereby preventing clogging and maintaining engine performance.
Implementation Method 1
the particles can separate out from the exhaust gas stream by thermophoresis, convection or diffusion. With particle separation by thermophoresis, the surfaces of the particle separator are cooled, so that the surfaces are significantly cooler than is the exhaust gas stream. As a result, the particles are deposited or precipitate on the surface
Implementation Method 2
With a particle separator designed according to the convection principle, this surface structure is configured such that the particles are constantly forced toward surface contact, and are then separated off at these surface structures
Implementation Method 3
Particle separators designed pursuant to the diffusion principle are provided with so-called flow dead zones, for example on the lee side of guide plates. In these flow dead zones, the flow velocity decreases toward zero, so that here the exhaust gas stream has a relatively long retention time, so that particles can diffuse out of the exhaust gas stream into the stream dead zones
Implementation Method 4
where they are catalytically oxidized with the NO2 produced at an oxidation catalytic converter
Data Source
AI summary
A particle separator and method for removing particles from an exhaust gas stream of an internal combustion engine. Differing flow regions having different flow conditions are formed in the particle separator. The differing flow regions are configured such that essentially particles having different, defined sizes and/or masses are adapted to be separated out of the exhaust gas stream in the differing flow regions. The exhaust gas stream is adapted to flow through at least portions of the particle separator.