Stratified Particulate Filter Regeneration Control
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Solution Overview
Problem
Existing exhaust gas treatment systems for internal combustion engines face challenges with uncontrolled regeneration of particulate filters, leading to thermal stress and potential cracking due to temperature gradients, and inefficiencies in multi-stage regeneration methods that do not account for stratified temperature structures and changing soot loading.
Innovation Solution
An exhaust gas treatment system with a control module, sensors, and a hydrocarbon supply that continuously adjusts the temperature set point based on the stratified temperature structure and particulate loading of the particulate filter, ensuring controlled regeneration by managing the temperature gradient and optimizing soot burning rates across different regions of the filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If multi-stage regeneration is used to control temperature, then temperature control is improved, but regeneration efficiency is reduced because the temperature set point is based on initial soot loading and does not account for stratified temperature structure
Solution Approach 1:
The patent implements dynamic temperature set point adjustment that continuously adapts to changing conditions during regeneration. The control system monitors actual temperature profiles and soot loading changes, then dynamically modifies the temperature set point to account for stratified temperature structure and evolving burn rates, transforming the static multi-stage approach into a dynamic adaptive system that maintains optimal regeneration efficiency throughout the process
Solution Approach 2:
The patent employs feedback control by continuously monitoring temperature at multiple locations within the filter and adjusting the temperature set point based on actual measured conditions. The control system uses feedback from temperature sensors and soot loading measurements to real-time adjust the regeneration temperature profile, ensuring the temperature set point reflects actual stratified conditions rather than relying on initial estimates
2Quantity of substance
If engine speed drops to idle during regeneration, then exhaust gas flow is reduced, but this creates uncontrolled regeneration that elevates PF temperature and causes thermal stress
Solution Approach 1:
The control system continuously monitors exhaust gas flow rate and oxygen concentration during regeneration, using feedback signals to detect conditions that may lead to uncontrolled temperature rise. When flow rate decreases or oxygen concentration increases, the system adjusts the temperature set point or hydrocarbon injection rate to compensate, preventing thermal runaway even during idle conditions
Solution Approach 2:
The system takes preliminary action by continuously monitoring regeneration conditions and proactively adjusting temperature set point or hydrocarbon delivery before uncontrolled temperature rise occurs. The control system anticipates potential thermal runaway scenarios during idle operation and preemptively modifies regeneration parameters to maintain temperature within safe limits
3Productivity
If temperature set point is raised to improve regeneration efficiency, then soot burning rate increases, but this creates higher temperature gradients that stress the filter substrate
Solution Approach 1:
The patent applies local quality control by monitoring and controlling temperature at different locations within the filter substrate. The system recognizes that temperature is not uniform throughout the filter and adjusts the temperature set point to account for local variations in soot loading, thermal mass, and heat transfer characteristics, thereby optimizing regeneration efficiency at each location while preventing excessive temperature gradients that would create thermal stress
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 minimizes the risk of uncontrolled regeneration, reduces thermal stress, and enhances regeneration efficiency by maintaining temperatures within material limits, thereby improving filter durability and reducing regeneration time, while ensuring efficient particulate removal.
Implementation Method 1
The hydrocarbon supply is selectively adjustable for delivery of a hydrocarbon to control an exhaust gas temperature
Implementation Method 2
The PF is in fluid communication with the exhaust gas conduit and has a filter structure for removal of particulates in the exhaust gas
Implementation Method 3
The PF has a stratified temperature structure that causes the particulates trapped at the innermost region of the PF burn off before the particulates trapped in the outermost region of the PF during regeneration
Data Source
AI summary
An exhaust gas treatment system for an internal combustion engine is provided and includes an exhaust gas conduit, a hydrocarbon supply, a particulate filter (“PF”), at least one sensor, a first temperature sensor, a second temperature sensor, and a control module. The PF is in fluid communication with the exhaust gas conduit and has a filter structure for removal of particulates in the exhaust gas. The filter structure has an innermost region and an outermost region. The PF is selectively regenerated during operation of the internal combustion engine. The PF has a stratified temperature structure that causes the particulates trapped at the innermost region of the PF burn off before the particulates trapped in the outermost region of the PF during regeneration. The control module has a memory with an infinite stage temperature control curve stored thereon.