PM Collapse Detection in Exhaust Filters via Differential Pressure
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Solution Overview
Problem
In exhaust purification devices, particulate matter (PM) collapse in filters due to condensation and subsequent water accumulation can lead to erroneous detection of PM excessive collection, causing potential filter damage and incorrect regeneration attempts.
Innovation Solution
A detection device that includes differential pressure acquisition, water generation determination, and collapse determination means to identify PM collapse by monitoring differential pressure and particulate matter accumulation, and performs filter regeneration when collapse is detected, while preventing regeneration in excessive collection states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If filter regeneration is periodically performed to remove accumulated PM, then PM removal efficiency is improved, but filter erosion or cracks may occur due to thermal runaway when PM is excessively accumulated
Solution Approach 1:
The system continuously monitors differential pressure across the filter and compares it against dynamic thresholds that account for PM collapse conditions. When the differential pressure exceeds the threshold during conditions favorable for PM collapse (low temperature, recent engine stop), the system adjusts regeneration timing to prevent excessive PM accumulation that could lead to filter erosion, while still maintaining effective PM removal through timely regeneration cycles.
2Device complexity
If PM accumulation is monitored using differential pressure to detect excessive collection, then PM accumulation detection is simplified, but erroneous detection occurs when PM collapses due to condensed water adhesion
Solution Approach 1:
The system proactively identifies conditions favorable for PM collapse (low exhaust temperature, recent engine stop, high humidity) before actual collapse occurs. By detecting these precursor conditions and combining them with differential pressure trends, the system can distinguish between genuine PM excessive collection and apparent increases caused by PM collapse, thereby preventing erroneous detection while maintaining simple differential pressure-based monitoring.
3Ease of operation
If the detection system uses only differential pressure thresholds to determine PM excessive collection, then the detection method is simple, but it cannot distinguish between actual PM excessive collection and PM collapse
Solution Approach 1:
The system dynamically adjusts the differential pressure threshold based on operating conditions that influence PM collapse likelihood. When conditions favoring PM collapse are detected (low temperature, recent engine stop), the threshold is raised to prevent false positives. This dynamic adaptation maintains simple threshold-based detection logic while significantly improving reliability by accounting for environmental factors that cause apparent differential pressure increases unrelated to actual PM accumulation.
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
Effectively detects PM collapse and prevents erroneous detection of excessive collection, ensuring proper filter operation and maintenance by accurately determining when PM has collapsed and performing necessary regeneration.
Implementation Method 1
differential pressure acquisition means for acquiring a differential pressure between an exhaust inlet side and an exhaust outlet side of the filter
Implementation Method 2
when the exhaust purification device is placed in a low-temperature environment after the engine is stopped, condensed water due to condensation or the like may be generated in an exhaust pipe
Data Source
AI summary
A detection device detecting collapse of PM collected in a filter provided in an exhaust system flow path of an internal combustion engine includes: a differential pressure sensor configured to acquire a differential pressure between an exhaust inlet side and an exhaust outlet side of the filter; a water generation determination unit configured to determine whether water is generated in the exhaust system flow path; and a PM collapse determination unit configured to determine that at least a part of the PM collected in the filter has collapsed when a PM accumulation amount estimated based on the acquired differential pressure has increased by a predetermined amount or more within a predetermined period in a state where the PM accumulation amount estimated based on the acquired differential pressure is equal to or larger than a predetermined first threshold and the water generation determination unit has determined that water is generated.