Gas Sensor Control Apparatus Stabilizing Pump Current
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional gas sensor systems require a long time to stabilize after switching target voltage for detecting H2O gas concentration, which disrupts the detection of oxygen concentration and leads to open-loop control of air-fuel ratio in engines.
Innovation Solution
A gas sensor control apparatus with distinct control constants for feedback control when switching target voltage, allowing for quicker stabilization of pump current, enabling simultaneous detection of H2O and oxygen concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the control target voltage is switched from the first reference voltage to the second reference voltage to detect H2O gas concentration, then the H2O gas concentration can be detected, but the pump current takes a long time to stabilize and oxygen concentration detection is interrupted
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing correction values that correspond to different pump current values before actual H2O concentration measurement. These correction values are prepared in advance based on the relationship between pump current and H2O concentration, allowing the system to quickly compensate for current instability without waiting for full stabilization. This enables the system to proceed with detection while the pump current is still transitioning, thereby reducing the interruption time for oxygen concentration detection.
Solution Approach 2:
The patent changes the parameter of control target voltage from a first reference voltage (for oxygen detection) to a second reference voltage (for H2O detection). This parameter change enables the sensor to switch between different detection modes. By accompanying this voltage change with switching between different sets of correction values, the system can detect H2O concentration while minimizing the time penalty, as the correction values are specifically tailored to compensate for the transient behavior at each voltage level.
2Measurement precision
If the control target voltage is switched to detect H2O gas concentration, then H2O concentration can be measured, but feedback control of air-fuel ratio cannot be performed during this period
Solution Approach 1:
The system performs preliminary calculation and storage of correction values that encode the relationship between pump current and H2O concentration. During H2O detection, instead of waiting for complete pump current stabilization before processing, the system uses these pre-prepared correction values to immediately compensate for current variations and calculate H2O concentration. This allows the detection process to overlap with the pump current transition period, minimizing the interruption to air-fuel ratio feedback control productivity.
Solution Approach 2:
The patent maintains continuity of useful action by enabling the H2O concentration calculation to proceed during the pump current stabilization period rather than waiting for it to complete. The correction values allow the system to continuously perform useful detection work even while the pump current is changing, ensuring that the transition between detection modes does not create a complete interruption in control functionality.
3Device complexity
If the first group of control constants continues to be used after target voltage switching, then the control system remains simple, but the pump current stabilization time increases
Solution Approach 1:
The patent applies dynamics by making the control constants adaptive rather than fixed. Instead of using a single static set of control constants, the system dynamically switches between a first group of control constants (optimized for oxygen detection at first reference voltage) and a second group of control constants (optimized for H2O detection at second reference voltage). This dynamic adjustment of control parameters allows the pump current to stabilize more quickly after voltage switching, reducing the time loss without significantly increasing system complexity, as the switching logic follows the voltage change.
Solution Approach 2:
The patent changes the parameters of the control constants themselves by providing different sets of constants for different operating conditions (different reference voltages and detection targets). The second group of control constants is specifically optimized to accelerate pump current stabilization when the second reference voltage is applied for H2O detection. This parameter change in the control constants, accompanied by the voltage switch, enables faster transient response while maintaining manageable system complexity through systematic organization of the constant sets.
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 apparatus reduces measurement time and allows for proper detection of H2O gas concentration without disrupting oxygen concentration detection, maintaining closed-loop control of air-fuel ratio.
Implementation Method 1
an electromotive force cell having an oxygen ion conductive first solid electrolyte body and a pair of first electrodes formed on the first solid electrolyte body
Implementation Method 2
a pump cell having an oxygen ion conductive second solid electrolyte body and a pair of second electrodes formed on the second solid electrolyte body
Data Source
AI summary
A gas sensor control apparatus (1) for a gas sensor (2) including an electromotive force cell (24) and a pump cell (14) includes current control means (69) for feedback-controlling the pump current Ip, voltage setting means S5, S13 for setting a target voltage Vr to either of first and second target voltage Vr1 and Vr2, and constant group setting means S4, S12 for setting a group of feedback control constants to a first group Kpid1 when the target voltage is Vr1 and to a second group Kpid2 when the target voltage is Vr2. The second group Kpid2 is determined such the pump current Ip becomes stable more quickly as compared with the case where the first group of control constants Kpid1 continues to be used.