Pt-Au Alloy Gas Sensor for High Concentration Hydrocarbon Detection
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Solution Overview
Problem
Conventional gas sensors are unable to accurately measure hydrocarbon gas concentrations beyond 2000 ppmC, which is insufficient for high concentration ranges encountered during diesel particulate filter regeneration or faulty fuel injectors, and lack sensitivity for unburned hydrocarbon detection in exhaust gases.
Innovation Solution
A mixed-potential gas sensor with a sensing electrode made of a Pt-Au alloy and an oxygen-ion conductive solid electrolyte, where the Au abundance ratio is between 0.1 and 0.3, enabling accurate measurement of hydrocarbon gas concentrations up to 16000 ppmC by disabling catalytic activity and utilizing a potential difference between the sensing and reference electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensing electrode made of Pt-Au alloy with increased Au abundance ratio is used to disable catalytic activity for hydrocarbon gas sensing, then detection sensitivity for high concentration hydrocarbon gas (up to 16000 ppmC) is improved, but the measurement range of conventional sensors (up to 2000 ppmC) is exceeded
Solution Approach 1:
The invention changes the chemical composition parameter of the sensing electrode by controlling the Au abundance ratio to be 0.05 or more and less than 0.5, which disables the catalytic activity and enables accurate measurement of high concentration hydrocarbon gas up to 16000 ppmC
Solution Approach 2:
The invention uses a composite Pt-Au alloy material for the sensing electrode, combining platinum and gold in specific ratios to achieve both adhesion to solid electrolyte and disabled catalytic activity for high concentration hydrocarbon gas detection
2Reliability
If a Pt-Au alloy with higher Au content is used to increase selective decomposition ability for oxygen, then the catalytic activity against hydrocarbon gas is disabled, but electrode impedance increases when Au abundance ratio exceeds 0.3
Solution Approach 1:
The invention optimizes the Au abundance ratio parameter to be 0.05 or more and less than 0.5, which is higher than conventional 0.01 or more and 0.3 or less, to achieve disabled catalytic activity while controlling electrode impedance through the specific composition range
3Measurement precision
If conventional gas sensors are used for hydrocarbon gas detection, then they can measure concentrations up to 2000 ppmC, but they cannot accurately measure concentrations beyond 2000 ppmC encountered during DPF regeneration or faulty fuel injectors
Solution Approach 1:
The invention changes the sensing electrode composition by setting Au abundance ratio to 0.05 or more and less than 0.5, which extends the measurable concentration range from 2000 ppmC to 16000 ppmC and improves accuracy in high concentration conditions
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 gas sensor effectively measures hydrocarbon gas concentrations in the range of 8000 to 16000 ppmC with enhanced sensitivity, addressing the limitations of existing sensors by providing accurate detection in higher concentration ranges.
Implementation Method 1
a sensor element mainly made of an oxygen-ion conductive solid electrolyte
Implementation Method 2
a gas sensor capable of sensing a hydrocarbon gas with high sensitivity... a sensing electrode made of Pt—Au alloy having an increased Au abundance ratio, a catalytic activity against a hydrocarbon gas is disabled, inducing a mixed potential having correlation with the concentration of the hydrocarbon gas
Data Source
AI summary
A gas sensor capable of measuring a high concentration range is provided. A sensing electrode provided in a sensor element of a mixed-potential gas sensor for measuring the concentration of a predetermined component in a measurement gas is formed of a cermet including a noble metal and an oxygen-ion conductive solid electrolyte. The noble metal includes Pt and Au. A Au abundance ratio, which is an area ratio of a portion covered with Au to a portion at which Pt is exposed in a surface of noble metal particles forming the sensing electrode, is 0.1 or more and less than 0.3.