Degraded Particulate Filter Pressure Sensor Soot Load Estimation
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Solution Overview
Problem
The degradation of particulate filter pressure sensors in vehicles can hinder the accurate assessment of soot load in carbonaceous soot traps, leading to drivability issues and increased emissions, as existing methods rely solely on pressure differential measurements which may be unreliable.
Innovation Solution
A method that utilizes both pressure sensor output during normal conditions and temperature sensor output when the pressure sensor is degraded to determine the soot load, allowing for timely purging of the carbonaceous soot trap, even when pressure data is unreliable, by correlating exhaust temperature with soot trap loading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pressure sensor is used to monitor soot load, then soot trap can be purged timely, but system reliability deteriorates when pressure sensor degrades
Solution Approach 1:
The system switches from monitoring pressure differential (original parameter) to monitoring exhaust temperature (alternative parameter) when the pressure sensor degrades. This parameter substitution allows the system to continue assessing soot load and triggering purges even when the original sensing method fails, thereby maintaining reliability while preserving the timely purging capability.
2Productivity
If pressure sensor data is used, then purging can be expeditious, but measurement precision deteriorates when sensor degrades
Solution Approach 1:
The exhaust temperature acts as an intermediary parameter to infer soot load when direct pressure measurement becomes unreliable. By monitoring exhaust temperature trends and using them to trigger purges, the system maintains measurement precision for soot load assessment even when the pressure sensor degrades, thus preserving both expeditious purging and accurate measurement.
3Reliability
If alternative temperature-based method is used when pressure sensor degrades, then system robustness is maintained, but device complexity increases
Solution Approach 1:
The exhaust temperature sensor serves dual purposes: it monitors engine operating conditions for general control and simultaneously provides soot load assessment data when the pressure sensor degrades. This multi-functionality allows the system to maintain robustness through a single existing sensor rather than adding dedicated backup systems, thereby avoiding increased device complexity while preserving reliability.
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 ensures the carbonaceous soot trap is purged efficiently, maintaining vehicle performance and fuel efficiency without increasing system costs, even when pressure sensor data is unreliable, thereby enhancing system robustness and customer satisfaction.
Implementation Method 1
Temperature in an exhaust system when an engine is stopped may be correlated to an amount of carbonaceous soot that is stored in a carbonaceous soot trap
Data Source
AI summary
Systems and methods for operating an engine that includes an exhaust system with a carbonaceous soot trap described. In one example, a carbonaceous soot load estimate for the carbonaceous soot trap is performed when a differential pressure sensor is degraded. The carbonaceous soot estimate may be performed when the engine is not rotating.