NOx Sensor SOx Recovery via Engine Stop Heating
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Solution Overview
Problem
NOx sensors are susceptible to poisoning by sulfur oxides (SOx), which reduces detection accuracy and requires prolonged heating for recovery, interfering with NOx concentration detection during engine operation.
Innovation Solution
A NOx sensor control device with a heater control unit that heats the sensor to a higher temperature when the engine stops, using an oxygen pump cell to facilitate SOx removal without interrupting NOx detection, and a recovery process counter to ensure complete SOx removal without unnecessary power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the NOx sensor is heated for a long time to remove SOx poisoning, then the detection accuracy is improved, but the NOx concentration cannot be detected throughout the heating period
Solution Approach 1:
The patent performs SOx removal heating in advance during engine stop periods before the engine operation resumes. This preliminary action ensures the sensor is ready for accurate NOx detection when the engine starts again, without compromising detection time during actual engine operation.
Solution Approach 2:
The patent implements periodic heating cycles at predetermined intervals during engine stop periods. This periodic action allows the sensor to undergo SOx removal treatment regularly without continuously interfering with NOx detection during engine operation, thus resolving the contradiction between detection accuracy and detection time.
2Reliability
If the sensor is heated at a higher temperature to surely remove SOx, then the SOx removal effectiveness is improved, but the energy consumption increases
Solution Approach 1:
The patent utilizes engine stop periods to perform high-temperature heating for SOx removal in advance. By doing this preliminary action when the engine is not running, the system can afford higher energy consumption during these periods without affecting overall energy efficiency, as the high-temperature heating is concentrated in non-operational windows.
Solution Approach 2:
The patent implements periodic high-temperature heating cycles at predetermined intervals during engine stop periods. This periodic approach ensures SOx removal effectiveness is maintained while limiting total energy consumption by confining high-temperature operation to specific time windows rather than continuous operation.
3Speed
If the heater is operated continuously to maintain sensor temperature, then the response speed is improved, but the energy consumption increases
Solution Approach 1:
The patent employs periodic heating control where the heater is operated intermittently rather than continuously. Heating is performed at predetermined intervals during engine stop periods, which maintains adequate sensor temperature and response speed while significantly reducing overall energy consumption compared to continuous operation.
Solution Approach 2:
The patent dynamically adjusts heater operation based on engine status and time intervals. The heater control is adapted to operate differently during engine operation versus engine stop periods, optimizing the balance between response speed and energy consumption by concentrating heating actions during non-operational periods.
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 removes SOx from NOx sensors without interfering with NOx concentration detection during engine operation, ensuring accurate NOx sensing by heating the sensor at a higher temperature and utilizing an oxygen pump to facilitate SOx removal in a reduction atmosphere.
Implementation Method 1
a recovery control of the NOx sensor which is an electric current control of the heater for removing SOx adsorbed to the NOx sensor
Implementation Method 2
each of which is formed by a solid electrolyte body, such as zirconia, having oxygen ion conductivity
Data Source
AI summary
A NOx sensor control device is connected to a NOx sensor mounted in an internal combustion engine. The NOx sensor has a detection cell configured to detect a NOx concentration and having a solid electrolyte body and a pair of electrodes provided on a surface of the solid electrolyte body and a heater heating the detection cell. The NOx sensor control device has a heater control unit. The heater control unit is configured to, at a time when an operation of the internal combustion engine stops, perform a recovery control of the NOx sensor which is an electric current control of the heater for removing SOx adsorbed to the NOx sensor.