DPF Regeneration Control Using DOC Temperature and Late Post-Injection
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Solution Overview
Problem
Existing diesel engine exhaust gas treatment systems face issues with excessive suppression of late post-injection to prevent white smoke, leading to increased DPF regeneration time.
Innovation Solution
A regeneration control apparatus that adaptively controls late post-injection amounts based on DOC temperature and air-fuel ratio to minimize white smoke generation without prolonging regeneration time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the upper limit value of the injection amount is determined only by the air-fuel ratio regardless of DOC temperature, then white smoke generation is prevented, but the injection amount is suppressed excessively and DPF regeneration time increases
Solution Approach 1:
The patent applies dynamics by making the upper limit value of the injection amount variable based on DOC temperature. Instead of using a fixed air-fuel ratio-based limit, the system dynamically adjusts the injection amount upper limit according to the actual DOC temperature conditions, allowing optimal injection amounts under different temperature scenarios while preventing white smoke only when necessary.
Solution Approach 2:
The patent changes the parameter used to determine the injection amount upper limit from a static air-fuel ratio parameter to a dynamic parameter that incorporates DOC temperature. This parameter change enables the system to adapt the injection control strategy to actual catalytic conversion conditions, avoiding unnecessary suppression when DOC temperature is sufficient for oxidation.
2Object-affected harmful factors
If a smaller injection amount is set to prevent white smoke at any temperature, then white smoke is suppressed, but the injection amount is limited unnecessarily and regeneration efficiency decreases
Solution Approach 1:
The system dynamically adjusts the injection amount based on DOC temperature conditions. When DOC temperature is high and sufficient for oxidation, the system allows larger injection amounts without excessive suppression. When DOC temperature is low, the system appropriately limits injection to prevent white smoke. This dynamic adjustment maintains regeneration efficiency while preventing harmful emissions only when necessary.
Solution Approach 2:
The patent introduces DOC temperature as a key parameter for determining injection amount limits. By changing from a fixed injection strategy to one that varies with DOC temperature, the system optimizes the balance between preventing white smoke and maintaining regeneration efficiency, allowing higher injection rates when catalytic conditions are favorable.
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 solution allows for effective DPF regeneration with reduced white smoke and minimized regeneration time by optimizing late post-injection amounts.
Implementation Method 1
The DOC is normally formed of ceramic or the like into a honeycomb-shaped monolith, similarly to the DPF, and supports an oxidization catalyst on the inner surface thereof
Implementation Method 2
the non-combusted fuel is discharged without being oxidized, which may lead to generation of white smoke
Implementation Method 3
The DPF is normally formed of ceramic or the like into a honeycomb-shaped monolith with adjacent vents closed alternately on the inlet side and the outlet side so that exhaust gas passes through filtering walls which remove PM
Implementation Method 4
diesel engine is equipped with an exhaust gas treatment apparatus including a diesel oxidation catalyst (DOC) disposed in an exhaust passage
Data Source
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AI summary
A regeneration control apparatus for controlling, in an exhaust gas treatment apparatus of a diesel engine including a diesel oxidation catalyst (DOC) disposed in an exhaust passage of an internal combustion engine and a diesel particulate filter (DPF) disposed downstream of the DOC, execution of forced regeneration to remove an exhaust particulate matter (PM) which accumulates on the DPF through a temperature increase of the DPF, includes: a late-post injection amount determination part which determines a late-post injection amount. The late-post injection amount determination part is configured to determine an upper limit value of the late-post injection amount on the basis of an air excess ratio of exhaust gas flowing into the DOC obtained on the basis of a temperature index of the DOC.