SOx Sensor Voltage Cycling for Accurate Exhaust Measurement
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Solution Overview
Problem
Existing SOx concentration acquiring apparatuses for internal combustion engines are inaccurate in measuring sulfur oxide concentrations due to the rate of change in sensor current not being sufficient to accurately reflect changes in exhaust SOx concentration.
Innovation Solution
The apparatus employs a control unit to execute voltage increasing and decreasing controls to enhance the rate of change in sensor current, allowing for accurate measurement by integrating differences between base and SOx concentration currents, thereby improving the accuracy of SOx concentration acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor voltage is simply increased to produce an electric potential difference, then the sensor current flows between electrodes, but the rate of change in sensor current is insufficient to accurately reflect changes in exhaust SOx concentration
Solution Approach 1:
The patent applies dynamics by making the sensor voltage variable rather than constant. The control unit dynamically adjusts the sensor voltage according to a predetermined pattern (increasing, holding, decreasing) to enhance the rate of change in sensor current. This dynamic voltage adjustment causes the sensor current to change more rapidly in response to SOx concentration changes, resolving the contradiction between measurement accuracy and response speed.
Solution Approach 2:
The patent changes the voltage parameter over time according to a specific pattern. By increasing the sensor voltage to a higher level, holding it there, then decreasing it, the system creates larger changes in sensor current that more accurately reflect SOx concentration changes. This parameter change approach transforms a static measurement into a dynamic one, improving both the rate of change and measurement precision.
2Measurement precision
If a simple voltage application method is used, then the device structure remains simple, but the SOx concentration acquisition accuracy is insufficient
Solution Approach 1:
The control unit executes voltage control based on predetermined patterns stored in the system. The system essentially serves itself by automatically adjusting voltages according to pre-programmed sequences without requiring complex external control mechanisms. This self-service approach improves measurement accuracy while keeping the control system relatively simple.
Solution Approach 2:
The patent employs periodic voltage adjustment cycles consisting of increasing, holding, and decreasing phases. This periodic action pattern creates consistent, repeatable measurement conditions that improve accuracy. The rhythmic voltage variations enable reliable SOx concentration detection without requiring continuously complex control logic.
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 enables precise and accurate measurement of SOx concentration by leveraging the enhanced rate of change in sensor current, ensuring reliable detection even in varying engine conditions.
Implementation Method 1
The sensor cell includes a solid electrolyte layer, a first sensor electrode, and a second sensor electrode. The first sensor electrode is provided on one of opposite surfaces of the solid electrolyte layer such that the first sensor electrode exposes to an exhaust gas discharged from the internal combustion engine.
Implementation Method 2
a first electromotive force generation unit... configured to generate a first electromotive force by electrochemical reactions between the sulfur oxide and the oxygen
Implementation Method 3
the control unit... calculates a SOx concentration of the exhaust gas on the basis of the first electromotive force and a concentration of the oxygen included in the exhaust gas
Data Source
AI summary
A SOx concentration acquiring apparatus of an internal combustion engine of the invention acquires sensor currents as SOx concentration currents after a sensor voltage reaches an oxygen decreasing voltage in a reoxidation voltage decreasing control, acquires the sensor current as a base current when the sensor voltage is equal to or lower than the oxygen decreasing voltage in the reoxidation voltage decreasing control, acquires an integration value of differences between the base current and each of the SOx concentration currents, and acquires a SOx concentration of an exhaust gas discharged from an internal combustion engine on the basis of the integration value.