Particle Sensor Ash Contamination Management
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Solution Overview
Problem
Particle sensors downstream of particle filters face reduced operational life due to ash contamination, which affects measurement accuracy and necessitates premature replacement, especially at semi-permeable and almost impermeable filter states.
Innovation Solution
A procedure and device that determine the remaining operating time of the particle sensor by assessing ash contamination, providing correction signals to maintain sensitivity and accuracy, and optimizing operating conditions such as voltage and heating to extend sensor life until legislative criteria are met, while avoiding early replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the particle sensor is operated downstream after a particle filter, then the measurement of particle concentration in exhaust gas is enabled, but the sensor is contaminated by ash that condenses on the measurement section, limiting its remaining operating time
Solution Approach 1:
The system performs preliminary determination of the remaining operating time based on ash contamination levels before the sensor becomes completely blocked. By continuously monitoring ash accumulation and calculating remaining operational life, the system can plan for timely replacement or regeneration, preventing measurement failure while maximizing sensor utilization.
Solution Approach 2:
The system uses feedback from ash contamination measurements to dynamically adjust operational parameters. By monitoring the impact of ash on measurement accuracy and providing feedback signals, the system can regulate operating conditions, trigger regenerative cycles, or alert operators to replace the sensor before complete contamination occurs.
2Reliability
If the particle filter is made almost impermeable to improve filtration efficiency, then particle capture is enhanced, but ash contamination on the particle sensor increases, reducing sensor reliability
Solution Approach 1:
The system converts the harmful effect of ash accumulation into a useful diagnostic signal. By monitoring ash contamination levels on the particle sensor, the system can determine the actual state of the particle filter's permeability and calculate remaining operating time, transforming the contamination problem into a monitoring opportunity that improves system reliability.
Solution Approach 2:
The system changes operational parameters based on ash contamination levels. By adjusting operating conditions such as temperature, flow rate, or sensor voltage based on measured ash accumulation, the system can maintain measurement accuracy while operating the sensor through varying filter permeability states.
3Measurement precision
If the particle sensor is replaced early to maintain measurement accuracy, then measurement reliability is preserved, but operational costs increase and sensor utilization is reduced
Solution Approach 1:
The system performs preliminary assessment of sensor contamination levels and calculates remaining operating time before replacement is actually needed. By determining when the sensor will reach unacceptable contamination levels, the system can optimize replacement timing to maximize sensor utilization while maintaining measurement accuracy, avoiding both premature replacement and measurement failure.
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
The particle sensor's operational life is extended, maintaining measurement accuracy and reducing costs by delaying replacement until necessary, even under ash contamination, ensuring compliance with legislative criteria.
Implementation Method 1
The impedance and/or its variation between the two electrodes can at least be used as a measure for the particle mass
Implementation Method 2
a particle filter (12) and a particle sensor (13) that is arranged downstream after the particle filter (12)
Implementation Method 3
there is a demand for detecting at least a measure for the particle concentration in the exhaust gas of combustion engines
Data Source
AI summary
A procedure for operating a particle sensor that is arranged downstream after a particle filter, at which an ash contamination can occur, and a device for implementing the procedure, are suggested. A remaining operating time determination determines the remaining operating time of the particle sensor related to an ash contamination. Alternatively or additionally the remaining operating time determination provides a correction signal, with which the sensitivity loss of the particle sensor caused by the ash contamination can be considered.