Gas-Sensor Control Device Off-Failure Detection via Neutralization Current
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Solution Overview
Problem
Existing gas-sensor control devices require complex timing control for acquiring voltage values to determine the off-failure of sweep and return sweep circuits, necessitating multiple voltage measurements which complicates the control process.
Innovation Solution
A gas-sensor control device that includes a sweep circuit, a return sweep circuit, an offset-voltage generating circuit, and an acquiring circuit, where the control portion calculates the gas sensor's impedance and temperature based on a single voltage value acquired during a neutralization current flow, allowing for off-failure detection without relying on voltage measurements during detection current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple voltage measurements are taken to determine off-failure of sweep and return sweep circuits, then the off-failure detection accuracy is improved, but the timing control complexity increases
Solution Approach 1:
The patent extracts the off-failure detection function from the impedance measurement process. By detecting off-failure during the neutralization current flow period when the gas sensor output is ideally zero, the system separates the diagnostic function from the normal measurement function, eliminating the need for complex timing control while maintaining detection accuracy
Solution Approach 2:
The patent uses the neutralization current flow period as an intermediary state for off-failure detection. During this period, the gas sensor should produce zero output, creating a known reference state that simplifies the detection process without requiring multiple measurements at different timing points
2Reliability
If voltage values are acquired multiple times to determine off-failure, then the reliability of off-failure detection is improved, but the control process complexity increases
Solution Approach 1:
The system uses the natural zero-output state of the gas sensor during neutralization current flow as a self-provided reference for off-failure detection. This self-service approach eliminates the need for external reference measurements or multiple voltage acquisitions, simplifying the control process while ensuring reliable detection
Solution Approach 2:
The patent performs off-failure detection during the neutralization current flow period, which is a preliminary action before the actual impedance measurement. By completing the diagnostic check in advance during a known zero-output state, the system ensures reliability without adding complexity to the main measurement process
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
Simplifies the timing control for acquiring voltage values and reduces the software configuration complexity by enabling off-failure detection of sweep and return sweep circuits using a single voltage measurement, thereby improving the efficiency of the gas-sensor control process.
Implementation Method 1
a solid electrolyte portion, an atmosphere-side electrode, and an exhaust-side electrode, wherein the solid electrolyte portion is interposed between the atmosphere-side electrode and the exhaust-side electrode
Data Source
AI summary
A gas-sensor control device includes a sweep circuit, a return sweep circuit, and a control portion. The sweep circuit energizes a detection current to flow through an oxygen sensor to calculates an impedance of the oxygen sensor. The return sweep circuit energizes a neutralization current to flow through the oxygen sensor in a direction opposite to a direction of the detection current, so as to remove electricity from the oxygen sensor that is energized by the detection current. The control portion executes a detection of an off failure of the sweep circuit and the return sweep circuit, only based on a sensor voltage acquired in a time period where the neutralization current flows through the oxygen sensor, and a threshold.