DFSO Length Control for Particulate Filter Regeneration
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Solution Overview
Problem
Particulate filters in vehicles may not reach passive regeneration conditions, leading to fouling and unnecessary reduction of deceleration fuel shut-off (DFSO) due to inaccurate estimation of soot load, which can result in particulate filter degradation.
Innovation Solution
Adjusting the length of DFSO and the number of activated/deactivated cylinders based on particulate filter temperature changes, assuming a maximum soot load to control oxygen flow and prevent excessive temperature during regeneration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If particulate filter regeneration is performed during DFSO based on estimated soot load, then the filter can be regenerated, but the estimated soot load becomes inaccurate due to ash load accumulation, leading to unnecessary reduction of DFSO length
Solution Approach 1:
The system uses feedback from temperature sensors to monitor actual filter temperature and adjusts DFSO length accordingly. The controller continuously monitors temperature changes during regeneration and modifies the DFSO duration to match actual regeneration progress, ensuring accurate control despite ash load accumulation.
Solution Approach 2:
The system changes the control parameter from estimated soot load to actual temperature measurement. By using temperature sensors to directly measure filter temperature and comparing it against threshold values, the system eliminates the inaccuracies of soot load estimation and adjusts DFSO length based on real thermal data.
2Object-affected harmful factors
If DFSO length is reduced to protect against filter degradation, then filter safety is improved, but the regeneration process is unnecessarily limited
Solution Approach 1:
The system implements feedback control by continuously monitoring filter temperature and adjusting DFSO length in real-time. When temperature approaches the threshold for filter degradation, the controller automatically shortens DFSO to prevent damage. When temperature is lower and safe, the system extends DFSO to maximize regeneration, thus optimizing both safety and efficiency.
Solution Approach 2:
The DFSO length is made dynamic rather than fixed. The controller continuously adjusts the DFSO duration based on real-time temperature measurements, transitioning between extended and reduced DFSO states as needed. This dynamic adjustment allows the system to maximize regeneration when safe and prevent degradation when temperature approaches critical levels.
3Productivity
If oxygen flow is increased to accelerate soot combustion, then regeneration speed is improved, but filter temperature exceeds maximum allowed levels causing degradation
Solution Approach 1:
The system dynamically adjusts oxygen flow rates during the regeneration process. The controller monitors temperature in real-time and modulates fuel injection to control oxygen availability to the filter. When temperature rises, oxygen flow is reduced to prevent overheating. When temperature is lower, oxygen flow is increased to accelerate regeneration, creating a dynamic balance between speed and temperature control.
Solution Approach 2:
The system changes the oxygen flow parameter dynamically during regeneration. By controlling fuel injection timing and duration, the controller varies oxygen availability to the particulate filter based on real-time temperature conditions. This parameter adjustment allows the system to optimize regeneration speed when temperature is safe and prevent thermal degradation when temperature approaches maximum limits.
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 allows for effective particulate filter regeneration during DFSO without overheating, extending the regeneration time if necessary, and preventing filter degradation by maintaining optimal oxygen levels.
Implementation Method 1
measures may be taken that result in an increase of the exhaust gas temperature above a predetermined level (e.g. above 450° C.) in order to incinerate the carbon particles accumulated in the filter
Implementation Method 2
incinerate the carbon particles accumulated in the filter
Implementation Method 3
increase of the exhaust gas temperature above a predetermined level (e.g. above 450° C.)
Data Source
AI summary
Methods and systems are provided for controlling a length of DFSO. In one example, a method may include adjusting the length of DFSO based on a particulate filter temperature change.