EGR Valve Flap Partition Reduces Condensate
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Solution Overview
Problem
In internal combustion engines, the formation of condensate due to the recirculation of exhaust gases can lead to increased noise and potential damage to the compressor impeller, reducing efficiency and longevity, particularly at higher exhaust-gas recirculation rates which are necessary for reducing nitrogen oxide emissions.
Innovation Solution
The engine system incorporates a valve unit with a pivotable flap and a flow-guiding device featuring partitions that separate the fresh air and recirculated exhaust gas, reducing their mixing and thus minimizing condensate formation by shortening the distance and time available for condensate droplet formation, and includes a positioning of the junction point close to the compressor to further mitigate this issue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If exhaust-gas recirculation rate is increased to reduce nitrogen oxide emissions, then emission reduction is improved, but condensate formation increases causing noise and impeller damage
Solution Approach 1:
The patent divides the airflow into separate streams using a partition wall within the valve housing. Fresh air and recirculated exhaust gas flow through separate pathways that are spatially segmented, preventing premature mixing and condensate formation while allowing high EGR rates for emission reduction.
Solution Approach 2:
The patent introduces a junction point as an intermediary element where exhaust gas is introduced into the fresh air stream. This junction point is strategically positioned and designed to control the interaction between hot exhaust gas and cooler fresh air, managing temperature gradients and preventing condensation while maintaining high recirculation rates.
2Device complexity
If fresh air and exhaust gas are mixed in the valve housing, then flow guidance is simplified, but condensate formation increases due to longer mixing time and distance
Solution Approach 1:
The valve housing incorporates a partition wall that segments the internal flow paths. This segmentation maintains separate channels for fresh air and exhaust gas, minimizing mixing time and distance while preserving a relatively simple overall valve housing structure.
Solution Approach 2:
The patent uses spatial arrangement in three dimensions within the valve housing to separate flow paths. The partition wall creates vertical or lateral separation of air streams, allowing independent flow paths without significantly increasing the external dimensions or complexity of the valve housing.
3Device complexity
If junction point is positioned farther from compressor, then valve unit design is simpler, but condensate droplets have more time to form and strike impeller
Solution Approach 1:
The patent positions the junction point close to the compressor inlet and designs the flow paths to ensure that exhaust gas and fresh air are properly mixed and warmed before reaching the compressor. This preliminary action prevents condensate formation upstream of the compressor, protecting the impeller even with the extended flow path.
Solution Approach 2:
The junction point acts as an intermediary zone where temperature and flow conditions are optimized before air enters the compressor. This intermediary region prevents condensation by maintaining appropriate temperature gradients and flow velocities, protecting the impeller from condensate droplets.
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 effectively reduces condensate formation, leading to decreased noise and impeller damage, thereby enhancing compressor efficiency and longevity while allowing for higher exhaust-gas recirculation rates to lower nitrogen oxide emissions.
Implementation Method 1
the interaction between the partition and the flap recess enables the gas flow (e.g., EGR gas flow and fresh air flow) entering the compressor to be separated to reduce the likelihood of condensation formation
Data Source
AI summary
An engine system is provided that includes a compressor including an inlet upstream of an impeller and a compressor housing, a flow-guiding device including a first partition extending across a valve housing, where the valve housing defines a boundary of an airflow duct, and a valve unit including an exhaust gas recirculation (EGR) valve coupled to a junction point between an EGR conduit and a compressor inlet and including and a flap having a recess mating with the first partition and pivoting about a mounting interface adjacent to a leading edge of the flap, a valve housing coupled to the compressor housing, where during actuation of the EGR valve a relative position between the recess in the flap and the first partition is varied.