Soot Sensor Voltage Control for Emission Monitoring
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Solution Overview
Problem
Current particle sensors for monitoring soot emissions in internal combustion engines struggle to accurately detect soot concentrations both upstream and downstream from the diesel particle filter, particularly due to varying soot concentrations and the inability to measure during regeneration, leading to measurement uncertainties and inefficiencies.
Innovation Solution
The method involves adjusting sensor sensitivity by applying different voltages to influence soot deposition rates, switching between higher and lower voltages to rapidly reach triggering thresholds and extend measuring times, allowing for optimal adaptation to specific application locations and reducing measurement uncertainties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a higher voltage is applied to the sensor, then the triggering time is reduced, but the measuring time is shortened
Solution Approach 1:
The sensor operating voltage is dynamically adjusted based on the soot accumulation state. During the accumulation phase, a higher voltage (U1) is applied to accelerate soot deposition and reduce triggering time. After triggering, the voltage is reduced to a lower level (U2) to extend the measuring time before the next regeneration cycle, thus resolving the time contradiction.
Solution Approach 2:
The sensor operates in periodic cycles with two distinct voltage levels. The first phase uses voltage U1 for rapid soot accumulation detection, and the second phase uses voltage U2 for extended measuring time. This periodic voltage switching allows the system to optimize both triggering speed and measuring duration across different operational phases.
2Measurement precision
If a higher voltage is applied to the sensor, then the sensitivity range is increased, but the sensor cannot detect soot during regeneration phase
Solution Approach 1:
The voltage applied to the sensor is dynamically changed based on the operational phase. During normal operation, voltage U1 provides high sensitivity for soot detection. During regeneration, the system switches to voltage U2 or temporarily suspends measurement, preventing damage while maintaining detection capability for subsequent cycles.
Solution Approach 2:
The system monitors sensor temperature and soot accumulation levels in advance to predict when regeneration will be needed. By detecting these preliminary indicators, the system can prepare for the regeneration phase by adjusting voltage levels before the actual burning occurs, ensuring continuous reliability.
3Ease of manufacture
If identical sensors are used for both upstream and downstream locations, then cost is reduced, but measurement accuracy varies due to different soot concentrations
Solution Approach 1:
The sensor operating parameters, particularly voltage level, are changed based on the application location and soot concentration. For high concentration environments (upstream), a different voltage regime is applied compared to low concentration environments (downstream), allowing a single sensor design to achieve optimal measurement accuracy across different locations.
Solution Approach 2:
A single sensor design with adjustable voltage capabilities serves multiple functions and locations. By electronically configuring the sensor for different operating conditions rather than manufacturing location-specific hardware variants, the system achieves universality while maintaining measurement precision across diverse applications.
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 enables precise soot concentration monitoring, enhances sensor reliability, and optimizes diesel particle filter operation by minimizing triggering time and maximizing measuring time, allowing for accurate detection of soot surges and extended sensor functionality.
Implementation Method 1
resistive particle sensors for conductive particles are known in which two or more metallic electrodes are provided, the particles, in particular soot particles, which deposit on these sensors short-circuiting the electrodes meshing in a comb-like manner and thus modifying the impedance of the electrode structure
Implementation Method 2
For regenerating the sensor element after the deposition of soot thereon, the sensor element must usually be burned free with the aid of an integrated heating element
Implementation Method 3
If a higher voltage is selected for operating the sensor, the soot layer builds up more rapidly than for a sensor operating with a lower voltage
Data Source
AI summary
A method is described for controlling the soot deposition on sensors. A sensor element is provided, which includes a first electrode and a second electrode. Different measuring voltages U1 and U2 can be applied to the sensor element. During a first time period t1, the sensor element is operated at a higher voltage U1 until a triggering threshold AP of the sensor element is exceeded, while it is operated at a voltage U2, which is different from higher voltage U1, U2 being lower than voltage U1, during a second time period t2.