Particle Sensor Drying Control to Prevent Thermal Shock
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Solution Overview
Problem
Existing methods for operating particle sensors in internal combustion engines do not adequately protect the sensor elements from thermal shock caused by water exposure, leading to potential damage during regeneration phases, especially in conditions where the sensor is not completely dry.
Innovation Solution
Extending the 'protective heating before the dew point' phase if a temperature deviation is detected, and using a timer and counter to ensure the sensor element is completely dry before regeneration, thereby preventing thermal shock damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor element is heated to high temperatures for regeneration, then soot buildup is removed, but thermal shock from water droplets can cause cracks in the sensor element
Solution Approach 1:
The system performs preliminary drying action by heating the sensor element to a first setpoint temperature (below dew point) before the regeneration phase. This preliminary action removes moisture from the sensor element, ensuring it is completely dry before high-temperature regeneration, thereby preventing thermal shock damage from water droplets
Solution Approach 2:
The system applies preliminary anti-action by detecting temperature deviations that indicate water contact and extending the protective heating phase accordingly. This counteracts the potential thermal shock effect before it can damage the sensor element during regeneration
2Reliability
If the protective heating phase duration is extended to ensure complete drying, then thermal shock damage is prevented, but the time required before regeneration increases
Solution Approach 1:
The system uses feedback by continuously monitoring the sensor element temperature and detecting deviations from expected temperature behavior. When a temperature deviation indicating water contact is detected, the system responds by extending the protective heating phase until the temperature stabilizes, ensuring complete drying while adapting the duration to actual conditions rather than using a fixed extended time
Solution Approach 2:
The system applies dynamics by making the protective heating phase duration variable rather than fixed. The heating phase extends dynamically based on real-time temperature monitoring, allowing the system to adapt the drying time to actual moisture conditions, thus preventing both premature regeneration and excessive waiting time
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
Ensures the sensor element is completely dry before regeneration, preventing damage from thermal shock and allowing safe high-temperature regeneration without risking sensor element cracking.
Implementation Method 1
the sensor element is dried using an integrated heating element
Implementation Method 2
the ceramic of the sensor element is heated to high temperatures, typically above 600°C. During this regeneration phase, the sensor element is sensitive to large local temperature changes or thermal shock
Data Source
Figure 1~2
AI summary
The invention relates to a method and to a device, in particular a control and evaluating unit, for operating a particle sensor (20) for determining a particle content in a gas flow, wherein the particle sensor (20) has, on the surface of the particle sensor, a sensor structure for determining a soot load and at least one heating element (26) separated from the sensor structure by an insulating layer, by means of which at least one heating element the particle sensor (20) can be heated up in a regeneration phase and in the process a soot load on the particle sensor (20) can be removed, and by means of the heating element (26) a heating phase can be performed at least at times before the regeneration phase, wherein in said heating phase a temperature that is significantly lower than the regeneration temperature is set, wherein short-term temperature drops as a result of wetting with water can be detected by means of a temperature sensor (27) integrated in the particle sensor (20). According to the invention, during the heating phase before the regeneration phase, the duration of the heating phase is extended if a temperature deviation from a certain temperature bandwidth around a temperature target value is detected for a certain time. Thus, it can be achieved that the sensor element is always completely dried throughout the sensor element, such that regeneration can be performed at high temperatures without damage as a result of thermal shock to the sensor element.