Particle Sensor Temperature Control for Exhaust Gas Measurement
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Solution Overview
Problem
Existing particle sensors in exhaust gas treatment systems face reduced availability due to condensation of water vapor at low temperatures, leading to interrupted measurement phases and reduced pro rata availability of particle sensor signals.
Innovation Solution
Monitoring the temperature of the sensor element during measurement phases and using a heating element to maintain the temperature above a limit temperature, typically between 50°C to 200°C, with a low heating output to prevent cooling and ensure continuous measurement phases, especially in hybrid drive and start-stop systems where critical cooling occurs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the sensor element is operated without heating during measurement phase, then energy consumption is reduced, but water vapor condenses on the sensor element below limit temperature, rendering current measurement unusable and interrupting measurement phase
Solution Approach 1:
The heating element operates periodically with different output levels: high heating output during regeneration phase and low heating output during measurement phase when temperature drops below limit temperature. This periodic action with variable intensity maintains temperature while optimizing energy consumption.
Solution Approach 2:
The heating output parameter is dynamically adjusted based on temperature conditions. The control unit changes the heating parameter from high output to low output depending on whether the sensor element temperature is above or below the limit temperature, optimizing both energy use and measurement reliability.
2Reliability
If the sensor element is heated to high temperature for regeneration, then soot particles are burned off and sensor is restored, but measurement phase must be interrupted and energy consumption increases
Solution Approach 1:
The heating process is segmented into two distinct phases: regeneration phase with high heating output for burning off soot, and measurement phase with low heating output for maintaining temperature. This segmentation allows continuous operation without interrupting measurement while still performing regeneration when needed.
Solution Approach 2:
The measurement phase continues uninterrupted by maintaining the sensor element temperature above the dew point using low heating output. The useful action of measurement is sustained continuously rather than being interrupted by regeneration cycles, improving time utilization.
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 prevents interruptions in measurement phases by maintaining the sensor element's temperature within a usable range, enhancing the overall availability and reliability of particle sensor signals.
Implementation Method 1
the sensor element is heated by the heating element if the temperature of the sensor element falls below a limit temperature
Implementation Method 2
the temperature of the sensor element can be monitored by means of a temperature measuring element that is integrated into the sensor element
Implementation Method 3
If the temperature of the sensor element falls below a limit temperature, for example 100° C., during the measurement phase, water vapor can condense on the sensor element
Data Source
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AI summary
Method for determining soot in exhaust gases of burners or internal combustion engines by means of a sensor element (10) which has at least two measuring electrodes (14, 16) exposed to the exhaust gas and a heating element (40), wherein a voltage (UIDE) is applied to the at least two measuring electrodes (14, 16) during a measuring phase and the current flow (IIDE) established between the measuring electrodes (14, 16) or electrical resistance is determined and is output as a measure of the particle concentration or the particle mass flow, characterized in that the temperature (T) of the sensor element (10) is monitored during the measuring phase and the sensor element (10) is heated by the heating element (40) if the temperature (T) of the sensor element (10) undershoots a limit temperature (TG).