Gasoline Particulate Filter Regeneration via Engine Parameter Control
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Solution Overview
Problem
Gasoline direct injected engines face challenges in meeting stringent Euro 6d and China 6 particulate emission limits due to the inability of gasoline particulate filters to regenerate effectively at low temperatures, especially during short trips or in cold weather, leading to insufficient soot burning.
Innovation Solution
An active regeneration strategy that uses a control module to adjust engine parameters such as spark timing, fuel injection timing, and the engine start-stop feature to increase the particulate filter temperature, enabling soot burning by leaning the air/fuel mixture and inhibiting fuel cutoff, and providing driver notifications for regeneration progress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive regeneration is used during fuel cutoff, then oxygen in the exhaust can purge the filter, but the exhaust system cannot reach sufficiently high temperature during short trips or cold weather operation
Solution Approach 1:
The system performs preliminary heating of the exhaust system by adjusting engine operating parameters (retarding spark timing, leaning air/fuel mixture) before regeneration is needed, ensuring the exhaust temperature reaches the threshold required for soot combustion even during short trips or cold weather operation
Solution Approach 2:
The system changes engine operating parameters including spark timing, air/fuel ratio, and fuel injection timing to control exhaust temperature and enable regeneration under varying operating conditions, transitioning from stoichiometric to leaner mixtures when regeneration is required
2Productivity
If the engine operates at stoichiometric ratio during normal operation, then combustion efficiency is optimized, but there is little or no oxygen in the exhaust to support passive regeneration
Solution Approach 1:
The system periodically switches between stoichiometric operation (for combustion efficiency) and lean operation with excess oxygen (for regeneration), using timing-based control to alternate between these two states and achieve both combustion efficiency and soot removal
Solution Approach 2:
The system dynamically adjusts the air/fuel ratio based on operating conditions, transitioning from stoichiometric mixtures during normal operation to leaner mixtures with excess oxygen when regeneration is required, allowing the system to adapt between conflicting requirements
3Object-generated harmful factors
If the particulate filter collects and retains particulate matter from exhaust, then emissions are reduced, but the filter becomes heavily loaded and requires regeneration
Solution Approach 1:
The system ensures continuous regeneration capability by maintaining conditions that allow soot combustion to occur periodically, preventing excessive soot accumulation and ensuring the filter continuously performs its emission reduction function without becoming blocked
Solution Approach 2:
The system uses feedback from sensors monitoring soot loading, exhaust temperature, and oxygen levels to determine when regeneration is needed and to control the regeneration process, adjusting engine parameters based on the filter's actual state to optimize both emission reduction and regeneration timing
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
Ensures effective regeneration of the gasoline particulate filter under varying conditions, maintaining emissions compliance by ensuring soot is burned off even at low temperatures, thereby extending filter life and meeting stringent emission standards.
Implementation Method 1
a control module (ECM) is commanded to adjust variables such as spark timing, fuel injection timing, valve timing, to inhibit the fuel cutoff or to inhibit the engine start-stop (ESS) feature
Implementation Method 2
a certain amount of oxygen in the exhaust will purge or regenerate the filter if it is at a sufficiently high temperature
Data Source
AI summary
The method determines whether soot loading of a gas particulate filter (GPF) requires regeneration. If it does, the temperature of the GPF is read to determine whether it is sufficiently high to achieve particulate (soot) burning. If it is not, an engine control module is commanded to adjust variables such as spark timing, fuel injection timing and valve timing. If the temperature of the particulate filter is sufficiently high that regeneration can occur, other variables may be adjusted such as leaning the air/fuel mixture, retarding the spark timing, the fuel injection and valve timing. Because the latter adjustments may limit or reduce either engine speed or power, messages in a message center are provided indicating, first, that the driver should continue driving for GPF regeneration and, subsequently, under certain conditions, that the engine power has been reduced. Operation of the motor vehicle proceeds until, based upon sensed conditions or pre-determined experimental or empirical data, the filter has been regenerated.