Exhaust Gas Recirculation Bypass for DPF Regeneration
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Solution Overview
Problem
Current exhaust gas treatment systems for Diesel engines, particularly Diesel particulate filters (DPFs), struggle to effectively capture finer particulate matter (PM2.5) and NOx emissions during regeneration, leading to environmental concerns and potential engine bans due to incomplete pollutant abatement.
Innovation Solution
The system redirects all released particulate matter from DPF regeneration back into the internal combustion engine for thorough combustion, utilizing a bypass duct to divert a fraction of exhaust gases around the first ATS portion, and incorporates NOx traps like NSC or PNA to coordinate regeneration, reducing NOx emissions through fuel reforming and recirculating exhaust gases to minimize atmospheric release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a Diesel particulate filter is used to reduce particulate matter emissions, then the total quantity by weight of particulate matter is reduced by 98%, but finer particulate matter (PM2.5) is not effectively captured and is released during regeneration
Solution Approach 1:
The patent converts the harmful effect of regeneration (releasing fine particles) into a beneficial process by recirculating the exhaust gas containing these particles back to the engine inlet, where they are completely combusted in the combustion chamber, transforming the regeneration event from a pollutant release occasion into an opportunity for complete pollutant destruction
Solution Approach 2:
The patent introduces an intermediary system consisting of a recirculation duct and control valve that mediates between the DPF regeneration process and the atmosphere, redirecting the exhaust stream containing fine particles back to the engine inlet rather than allowing direct atmospheric release
2Productivity
If the DPF is regenerated periodically to maintain filtration efficiency, then captured particulate matter is removed, but fine particles are released into the atmosphere during the regeneration process
Solution Approach 1:
The harmful release of fine particles during DPF regeneration is converted into a beneficial combustion process by recirculating these particles back to the engine, where they serve as additional fuel or are completely oxidized, eliminating the pollutant release issue while maintaining regeneration functionality
3Adaptability or versatility
If a bypass duct is used to divert exhaust gases during regeneration, then thermal flexibility is improved, but the system complexity increases
Solution Approach 1:
The recirculation duct serves multiple functions simultaneously: it enables thermal management during regeneration, maintains system pressure balance, and provides a pathway for complete pollutant destruction, thereby achieving thermal flexibility without proportionally increasing system complexity
Solution Approach 2:
The system uses its own exhaust gas as the recirculation medium, eliminating the need for external pumps or additional energy input, as the exhaust pressure differential naturally drives the recirculation flow through the duct
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 approach significantly reduces NOx and PM2.5 emissions during regeneration, maintaining fuel balance and extending engine life by utilizing the engine as an abatement device, while also improving thermal flexibility and compliance with stringent emission regulations.
Implementation Method 1
the internal combustion engine acts like an abatement device, thorough combustion, for the suspended particulate matter released during the regeneration of the DPF
Implementation Method 2
NSC = NOx trap, which converts NO into NO2 and stores it until N02 needs to be reduced
Implementation Method 3
DPF = Diesel particulate filter, which is capable of storing particulate matter with dimensions exceeding PM10
Implementation Method 4
SCR = selective catalytic converter, which exploits the presence of ammonia to reduce NOx contained in exhaust gases
Data Source
Figure 1~2a
Figure 2b~2c
Figure 2d~2e
AI summary
A system for the abatement of the pollutants produced by an internal combustion engine (E) having an intake pipe (IP) and an exhaust pipe (EP), the system comprising a device (ATS) for the abatement of the pollutants contained in the exhaust gases produced by the internal combustion engine, wherein said ATS device comprises at least a first exhaust gas treatment portion (ATS1) comprising a Diesel particulate filter (DPF, cDPF, SCRoF), a bypass duct (BP) adapted to bypass said first treatment portion and arranged for connecting a first point, upstream of the first treatment portion (ATS1), to a second point, downstream of the first treatment portion, a recirculation pipe (EGRP) which connects a third point, arranged between said first treatment portion (ATS1) and said second point, to the intake pipe (IP) of the internal combustion engine, a first valve (FP) arranged to selectively cause a first operating condition, in which there is a transit of exhaust gas, that passes through said first treatment portion (ATS1) towards said second portion, and a consequent occlusion of said bypass duct, and a second operating condition, in which there is a transit of exhaust gas, that passes through said first treatment portion (ATS1) towards said recirculation pipe, and a consequent opening of said bypass duct.