Particulate Filter Regeneration via Exhaust Routing Valves
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing exhaust treatment systems for combustion engines face challenges in efficiently managing soot load in particulate filters, particularly due to infrequent passive regeneration opportunities and interference with exhaust gas recirculation flow, leading to combustion instability and incomplete filter regeneration.
Innovation Solution
A method involving the use of a branched exhaust passage system with multiple valves to control the direction of exhaust flow, allowing for coordinated soot purging and regeneration through reverse and forward flows, respectively, while the engine is fueled and unfueled, to reduce soot loading and minimize active regeneration needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive regeneration is used during DFSO mode, then soot incineration occurs, but regeneration opportunities are infrequent
Solution Approach 1:
The system performs preliminary soot accumulation during normal operation, then executes concentrated regeneration during DFSO events by routing exhaust through the filter. The filter is designed to hold soot load until regeneration conditions arise, making effective use of infrequent DFSO opportunities.
Solution Approach 2:
The system uses periodic DFSO events as regeneration opportunities. The exhaust routing valve periodically switches to route exhaust through the filter during these events, creating a periodic regeneration cycle that matches the natural occurrence of DFSO conditions.
2Reliability
If active regeneration is used with rich/lean engine operation, then soot incineration is facilitated, but fuel economy drops
Solution Approach 1:
The system converts the normally wasted thermal energy in exhaust gas during DFSO mode into a beneficial regeneration process. Instead of letting exhaust simply bypass the filter, the routing valve directs it through the filter to incinerate soot, transforming thermal waste into a cleaning mechanism.
Solution Approach 2:
The system uses the engine's own exhaust heat during DFSO mode to regenerate the filter, without requiring external energy input or fuel injection. The exhaust gas self-regenerates the filter passively as it flows through during deceleration events.
3Reliability
If EGR flow is increased to purge HCs, then filter regeneration is facilitated, but combustion stability decreases
Solution Approach 1:
The system segments the exhaust flow control into two independent pathways: one for EGR (controlled by EGR valve) and one for filter regeneration (controlled by exhaust routing valve). This allows regeneration flow to be added to the system without interfering with the precisely controlled EGR flow needed for combustion stability.
Solution Approach 2:
The exhaust routing valve acts as an intermediary that introduces regeneration flow through a separate pathway. This mediator component allows the system to add purge flow for regeneration without directly disrupting the EGR flow that maintains combustion stability.
4Stability of the object's composition
If EGR valve is closed during torque transients, then combustion stability is maintained, but filter purging is interrupted
Solution Approach 1:
The system separates EGR control from regeneration control into independent valve systems. The EGR valve can be closed during torque transients to maintain combustion stability, while the exhaust routing valve independently manages regeneration flow through the filter, preventing interruption of the purging process.
Solution Approach 2:
The exhaust routing valve serves as an intermediary that maintains regeneration flow independently of EGR valve actions. During torque transients, this mediator ensures continuous purge flow through the filter even when the EGR valve closes to protect combustion stability.
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 enables more complete filter cleaning over a drive cycle, reduces the need for fuel-intensive active regeneration, and maintains combustion stability by leveraging the higher tolerance of the engine to low purge flows during idling conditions.
Implementation Method 1
Flow of this hot exhaust gas through the particulate filter can cause at least some of the carbon particles accumulated in the filter to incinerate
Data Source
AI summary
Methods and systems are provided for regenerating and purging a particulate filter of an exhaust treatment system for a combustion engine. In one example, a method may include flowing exhaust gas in a reverse direction through the particulate filter to purge particulate matter to an intake manifold of the engine for combusting. The duration of purging may be based on a regeneration achieved during a previous regeneration of the particulate filter during a deceleration fuel shut-off event.