Diesel Particulate Filter PM Slip-Through Control
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Solution Overview
Problem
The exhaust gas purification system with a diesel particulate filter (DPF) experiences a temporary increase in particulate matter (PM) emission due to PM slip-through after forced regeneration treatment, which deteriorates emission performance and increases the total amount of PMs emitted to the atmosphere.
Innovation Solution
Implementing a control system that temporarily enhances surface filtration cake layer formation or reduces PM generation immediately after PM re-combustion in the DPF, using techniques such as increasing exhaust gas recirculation rate, retarding fuel injection timing, and adjusting air-fuel ratio to enhance PM trapping and reduce PM slip-through.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If forced regeneration treatment is performed on the DPF to re-combust trapped PMs, then the PM trap efficiency is improved and the amount of PMs emitted to the atmosphere is reduced, but the PM slip-through increases temporarily causing deterioration in emission performance
Solution Approach 1:
The control device performs preliminary action by detecting the completion of PM re-combustion through temperature monitoring and proactively switching to post-injection control before PM slip-through can significantly occur. This timing-based preventive approach addresses the contradiction by acting at the critical transition point.
Solution Approach 2:
The invention changes operational parameters by switching from forced regeneration mode to post-injection mode, altering the chemical and thermal environment in the DPF. This parameter change allows the system to transition from high-temperature combustion to a cooler state where PM slip-through is minimized through controlled fuel injection.
2Loss of substance
If the surface filtration cake layer is combusted during forced regeneration treatment, then the trapped PMs are removed, but the PM trap efficiency is temporarily lowered causing PM slip-through
Solution Approach 1:
The invention maintains continuity of useful action by immediately initiating post-injection control after forced regeneration completion, ensuring that the DPF transitions smoothly from PM removal to PM trapping mode without significant interruption. This continuous control approach prevents the temporary efficiency loss that would otherwise occur.
Solution Approach 2:
The control device uses feedback from temperature sensors to detect when PM re-combustion is complete and automatically adjusts injection strategies accordingly. This closed-loop feedback mechanism ensures the system responds appropriately to the actual state of the DPF, switching modes at the optimal moment to maintain PM trap efficiency.
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 effectively reduces the total amount of PMs emitted to the atmosphere by promoting early and enhanced formation of the surface filtration cake layer, thereby minimizing PM slip-through and improving emission performance.
Implementation Method 1
a DPF that traps PMs is provided in the exhaust passage of the internal combustion engine
Implementation Method 2
a forced regeneration treatment for the re-combustion of the trapped PMs is performed on the DPF by raising the temperature of the DPF
Implementation Method 3
the re-combustion of the trapped PMs is performed on the DPF by raising the temperature of the DPF
Implementation Method 4
PMs with relatively large particle sizes do not pass through the wall surface, but are attached to a front side (upstream side) of the wall surface to form a surface filtration cake layer
Data Source
AI summary
An exhaust gas purification system with a diesel particulate filter in an exhaust passage of an internal combustion engine. A surface filtration cake layer formation enhancement control or a particulate matter generation amount reduction control is temporarily performed immediately after a forced regeneration treatment on the diesel particulate filter. The system and a method are directed to a particulate matter slip-through phenomenon in which the particulate matter slip-through amount temporarily increases immediately after particulate matter re-combustion in a forced regeneration treatment on the diesel particulate filter. The diesel particulate filter is disposed in the exhaust passage of the internal combustion engine and reduces the total amount of particulate matter emitted to the atmosphere immediately after the particulate matter re-combustion in the forced regeneration treatment on the diesel particulate filter.