Gas Sensor Controller Oxygen Threshold Activation
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Solution Overview
Problem
Existing gas sensors face delays in activation due to unnecessary reduction control implementation, particularly after engine restarts, which can lead to inaccurate NOx concentration detection and prolonged activation times.
Innovation Solution
A controller is configured to selectively implement normal and reduction controls, determining whether reduction control is necessary to avoid unnecessary hydrogen generation and disablement of the sensor cell, thereby accelerating sensor activation and improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reduction control is implemented continuously to reduce oxidized electrodes, then electrode reduction is improved, but activation time is prolonged and detection accuracy deteriorates due to unnecessary hydrogen generation
Solution Approach 1:
The controller performs preliminary assessment by detecting oxygen concentration before implementing reduction control. This preliminary action prevents unnecessary reduction control execution, thereby avoiding unnecessary hydrogen generation and sensor cell disablement, which accelerates sensor activation while maintaining detection accuracy.
Solution Approach 2:
The system uses oxygen concentration detection as feedback to dynamically control the execution of reduction control. When oxygen concentration is below the threshold, reduction control is executed; when above, it is suppressed. This feedback mechanism eliminates unnecessary reduction control, preventing activation delays and ensuring accurate NOx detection.
2Loss of time
If reduction control is suppressed to avoid unnecessary hydrogen generation, then activation time is improved, but electrode reduction capability deteriorates
Solution Approach 1:
The oxygen concentration detection provides feedback that dynamically adjusts reduction control execution. This ensures reduction control is executed only when necessary (low oxygen conditions), maintaining electrode reduction capability while avoiding unnecessary executions that would prolong activation time.
Solution Approach 2:
The system changes the operational parameter (reduction control execution) based on the detected oxygen concentration parameter. This conditional parameter adjustment ensures reduction control is applied only when oxygen concentration is below the threshold, balancing activation speed with electrode maintenance.
3Productivity
If oxygen concentration detection is used to control reduction control execution, then unnecessary reduction control is prevented, but system complexity increases
Solution Approach 1:
The oxygen concentration detection unit serves multiple functions: it monitors oxygen levels for sensor operation and simultaneously controls reduction control execution. This multi-functionality prevents unnecessary reduction control while maintaining relatively simple system architecture, improving activation speed without excessive complexity increase.
4Reliability
If reduction control is executed frequently to maintain electrode condition, then electrode reliability is improved, but energy consumption increases
Solution Approach 1:
Oxygen concentration detection provides feedback that controls reduction control execution frequency. Reduction control is executed only when oxygen concentration is below the threshold, preventing frequent unnecessary executions and reducing energy consumption while maintaining adequate electrode condition.
Solution Approach 2:
Instead of continuous reduction control, the system applies partial action by executing reduction control only when necessary (low oxygen conditions). This partial execution maintains electrode reliability while significantly reducing energy consumption compared to continuous execution.
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 solution prevents unnecessary reduction control, reducing activation delays and enhancing NOx concentration detection accuracy by ensuring the gas sensor is activated promptly and accurately.
Implementation Method 1
a first cell includes a first electrode, which is provided in a measurement gas chamber configured to introduce gas to be detected, and a second electrode, which is provided in a reference gas chamber configured to introduce reference gas. The first cell is configured, on application of a voltage between the first electrode and the second electrode on the gas to be detected to remove oxygen in the gas to be detected.
Implementation Method 2
a second cell includes a third electrode, which is provided in the measurement gas chamber, and a fourth electrode, which is provided in the reference gas chamber. The second cell is configured, on application of a voltage between the third electrode and the fourth electrode, to cause a current to flow between the third electrode and the fourth electrode. The current corresponds to a concentration of a specific gas component in the gas to be detected after the oxygen is removed by the first cell.
Data Source
AI summary
A first cell includes a first electrode in a measurement gas chamber and a second electrode in a reference gas chamber. A second cell includes a third electrode in the measurement gas chamber and a fourth electrode in the reference gas chamber to cause a current therebetween that corresponds to a concentration of a specific gas component in detected gas in the measurement chamber. A controller selectively implements a normal control and a reduction control. The normal control is to apply a lower voltage to the first electrode and the second electrode to remove oxygen from the detected gas. The reduction control is to apply a higher voltage to the first electrode and the second electrode to reduce the third electrode that is oxidized. The controller prohibits implementation of the reduction control on determination that implementation of the reduction control.