Gas Sensor Control Apparatus Response Time Optimization
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Solution Overview
Problem
Gas sensors, particularly O2 sensors, experience a time lag in responding to changes in air-fuel ratios, leading to decreased responsivity and accuracy in measuring exhaust gas compositions, which is not effectively addressed by existing technologies that require complex modifications to the sensor structure.
Innovation Solution
A gas sensor control apparatus that uses a constant current circuit connected to the gas sensor's electrodes to supply a constant current and a controller that determines the direction of current flow based on requested changes in output characteristics, such as response time, to accelerate or decelerate the removal of interfering gas components, thereby improving the sensor's responsiveness without altering the sensor structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a constant current circuit is connected to the gas sensor electrodes to supply constant current for changing output characteristics, then the response time of the gas sensor is improved, but the device complexity increases due to additional control apparatus
Solution Approach 1:
The patent applies parameter changes by utilizing the existing gas sensor electrodes as both sensing and current supply paths. The controller changes the output characteristic by controlling the direction and magnitude of constant current flow through the electrodes, rather than adding separate actuation mechanisms. This resolves the contradiction by achieving response time improvement through electrical parameter control without proportionally increasing mechanical or structural complexity.
2Loss of time
If the structure of the gas sensor is modified to improve response time, then the response time is improved, but the ease of manufacture deteriorates due to complex modifications
Solution Approach 1:
The patent implements universality by making the gas sensor electrodes serve dual functions: detecting gas component concentrations and serving as current supply paths for changing output characteristics. This eliminates the need for separate actuation structures, maintaining ease of manufacture while achieving response time improvement through the multi-functional use of existing components.
Solution Approach 2:
The gas sensor structure is designed to be self-sufficient by using its own electrodes for both sensing and actuation purposes. The constant current circuit utilizes the existing electrode structure without requiring additional external components, allowing the sensor to change its own output characteristics through controlled current flow between its inherent electrodes.
3Measurement precision
If constant current is applied to change the output characteristic of the gas sensor, then the measurement precision is improved, but the use of energy increases due to continuous current supply
Solution Approach 1:
The patent implements periodic action by controlling the constant current circuit to supply current only when output characteristic changes are required, rather than continuous current supply. The controller activates the constant current based on detected gas component concentration changes or specific operating conditions, achieving measurement precision improvement while minimizing energy consumption through on-demand current application.
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 effectively reduces response time lag and enhances the accuracy of gas sensor outputs by controlling the flow of current to manage interfering components, allowing for precise adjustments based on operating conditions and air-fuel ratio changes, thus improving engine control system performance and emission management.
Implementation Method 1
The electric current is applied to the auxiliary electrochemical cell to perform the so-called ion pumping, thereby changing the concentration of gas to be measured
Implementation Method 2
typical electromotive force O2 sensors work to output an electric signal which is different in level between when the exhaust gas is rich in fuel and when the exhaust gas is lean in fuel
Data Source
AI summary
A gas sensor control apparatus is provided which controls an operation of a gas sensor made up of a solid electrolyte body and a pair of electrodes to output a signal indicating the concentration of a given gas component contained in gas. The gas sensor control apparatus includes a constant current circuit that is connected electrically to one of the electrodes of the gas sensor and supplies a constant current thereto and a controller. The controller supplies a constant current to the gas sensor so that it flows from one of the electrodes to the other in a selected direction, thereby changing a response time the gas sensor takes to react to a change in concentration of the gas component. This results in an increased accuracy, for example, in controlling an air-fuel ratio of a mixture to an internal combustion engine in an engine control system.