Heatable EGR Particle Filter for Low-Pressure Exhaust Recirculation
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Solution Overview
Problem
Low-pressure exhaust-gas recirculation systems in internal combustion engines experience higher back pressure and longer unburned mass build-up during low-load operation compared to high-pressure systems, leading to inefficiencies.
Innovation Solution
Incorporating a heatable second particle filter in the EGR line upstream of the first particle filter, which reduces mass flow through the first filter and oxidation catalytic converter, and uses selective heating to combust soot and oil particles, thereby reducing the risk of filter blockage and allowing for a smaller filter design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a low-pressure EGR system is used, then the system structure is simpler and installation is easier, but back pressure increases and response speed decreases during low-load operation
Solution Approach 1:
The patent applies parameter changes by implementing selective heating of the particle filter to maintain optimal operating temperature under varying load conditions. This allows the low-pressure EGR system to achieve both structural simplicity and improved response speed by dynamically adjusting the filter temperature parameter, preventing soot accumulation that would otherwise slow down the system response during low-load operation
2Reliability
If a conventional particle filter is used in the EGR line, then soot and oil particles are filtered, but the filter volume must be large and blockage risk increases
Solution Approach 1:
The patent changes the temperature parameter of the particle filter by implementing selective heating, which transforms the filter from a passive filtration device to an active combustion chamber for soot particles. This parameter change enables a significant reduction in filter volume while maintaining or improving anti-blockage performance, as the heated filter actively combusts soot rather than merely trapping it
Solution Approach 2:
The patent converts the harmful soot and oil particles that would normally accumulate and block the filter into a beneficial combustion process. By heating the particle filter selectively, the previously harmful accumulated soot becomes fuel for combustion, generating heat that further assists in particle oxidation and prevents blockage, thus turning the filter's weakness into a strength
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 reduces exhaust-gas back pressure, improves response speed of the EGR system, and prevents filter blockage by combusting soot and oil particles, allowing for a significantly smaller filter volume and reduced risk of compressor degradation at low turbocharger speeds.
Implementation Method 1
Soot and oil particles which are contained in the recirculated exhaust gas, and which may not pass into the compressor of the turbocharger, can be combusted by means of the heatable particle filter
Data Source
AI summary
The description relates to an internal combustion engine having a turbocharger, having a first particle filter in the intake section of the internal combustion engine and having a low-pressure EGR line that comprises a second particle filter. A fast-reacting low-pressure exhaust gas recirculation system with small dimensions can be realized by virtue of the EGR line branching off from the exhaust section upstream of the first particle filter, and the second particle filter being provided with a heater. The description also relates to a corresponding EGR method.