Emission Control Device Regeneration via Oxygen Storage
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Solution Overview
Problem
Spark-ignition engines face challenges in supplying excess oxygen for particulate filter regeneration due to stoichiometric operating conditions, leading to depletion of oxygen stored in the exhaust system, which limits passive filter regeneration and increases the frequency of modifying engine operation for active regeneration, affecting fuel economy and vehicle drivability.
Innovation Solution
A method for an emission control device with a catalyst and filter that passively regenerates the filter and adjusts the duration of active regeneration based on the oxygen storage capacity, including determining the amount of particulate matter and extending deceleration fuel shut-off to replenish oxygen, thereby reducing the frequency of engine operation modifications for filter regeneration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If deceleration fuel shut-off is used to supply excess oxygen for filter regeneration, then the regeneration reaction can proceed, but oxygen stored in the exhaust system is completely consumed and cannot be replenished
Solution Approach 1:
The system performs preliminary oxygen storage in the catalyst washcoat during normal operation, so that when regeneration is needed, the stored oxygen is available to support the regeneration reaction without requiring complete consumption of reserve oxygen
Solution Approach 2:
The controller monitors oxygen storage capacity and adjusts the duration of deceleration fuel shut-off accordingly, extending the duration when oxygen storage is low to replenish oxygen reserves while maintaining filter regeneration capability
2Reliability
If active regeneration is performed frequently to maintain filter performance, then filter regeneration is ensured, but fuel economy and vehicle drivability are adversely affected
Solution Approach 1:
The controller continuously monitors oxygen storage capacity and adjusts active regeneration duration dynamically, extending duration only when oxygen storage is insufficient, thereby minimizing the frequency and duration of engine operation modifications while ensuring filter regeneration
Solution Approach 2:
The system changes the duration parameter of deceleration fuel shut-off based on oxygen storage capacity, optimizing the balance between filter regeneration needs and fuel economy by performing regeneration only when necessary
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 increases the frequency of passive filter regeneration, improves fuel economy, and enhances vehicle drivability by optimizing oxygen use and reducing the need for frequent engine operation modifications for active regeneration.
Implementation Method 1
passively regenerating the filter
Implementation Method 2
actively regenerating the filter includes initiating deceleration fuel shut-off
Data Source
AI summary
Various methods are provided for operating an emission control device. In one example, a method for an emission control device including a catalyst and a filter comprises passively regenerating the filter, and adjusting, via a controller, a duration of active regeneration of the filter based on an oxygen storage capacity of the emission control device.