Gas and particle sensor using voltage and current behavior between electrodes during glow-to-arc transition
Inventors
Aldayeh, Maher Abdulhamid • Abdul-Khalek, Imad Said
Assignees
Southwest Research Institute SwRI
Publication Number
US-11959878-B2
Publication Date
2024-04-16
Expiration Date
2040-01-03
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Abstract
A sensor for detecting properties of a gas, gas mixture, or a gas or gas mixture containing particles, all collectively referred to as a “gas”. A flow tube contains a pair of electrodes arranged such that at least a portion of the gas flows between the electrodes. A controller applies voltage to the electrodes and measures response data from the electrodes representing the voltage-current relationship between the electrodes while the gas is between the electrodes. Based on the response data, the controller determines a concentration of particles within the gas.
Core Innovation
The invention provides a sensor system for detecting properties of gases, gas mixtures, and gases or mixtures containing particles, collectively referred to as a 'gas.' The core system comprises a flow tube with a pair of electrodes positioned so that gas flows between them. A controller applies increasing voltages to the electrodes and measures the current and voltage response, allowing the determination of gas species, gas concentration, and particle concentration if particles are present.
This system exploits the unique signatures in voltage breakdown and the voltage-current relationship between electrodes. These signatures are influenced by factors such as gas composition, particle presence and concentration, pressure, and temperature. By analyzing a specific portion of the voltage-current profile—especially the transition region to voltage breakdown after the saturation regime—the sensor can determine the concentration and characteristics of particles within the gas.
The problem addressed is the need to accurately detect and characterize gases and particulate content using the electrical behavior between electrodes, particularly the glow-to-arc transition, as defined by Paschen's law. Existing techniques require improved ways to resolve both particle and gas properties, especially in real-time and in applications such as monitoring vehicle exhaust.
Claims Coverage
There are three independent claims, each introducing a distinct inventive feature for detecting particle concentration in gases by analyzing the transition in the voltage-current profile between electrodes.
Sensor system using transition region of voltage-current profile to determine particle concentration
A sensor comprising a flow tube with a pair of electrodes arranged so that at least a portion of gas flows between them, and a controller that applies increasing voltages to the electrodes while measuring current values. The controller determines the concentration of particles within the gas by analyzing a signature representing only a portion of the voltage-current profile, specifically the transition to voltage breakdown after a saturation regime. The distance between electrodes is predetermined based on detection of signatures for an expected range of particle sizes.
Method for detecting particle concentration using transition to voltage breakdown
A method that involves delivering gas to a sensor with a flow tube and electrodes, applying increasing voltages as gas flows through the electrodes, measuring the current between the electrodes, and determining the concentration of particles by analyzing a signature representing only the transition region to voltage breakdown after saturation. The electrode spacing is predetermined based on expected particle size signatures.
Vehicle emissions sensor detecting particulate content based on voltage-current signature transition
A vehicle emissions sensor including a flow tube and electrodes positioned so that gas flows between them, with the electrode gap predetermined for the expected particle size range. A controller applies increasing voltage and measures current values, processing the response data to determine particle concentration by analyzing the transition region of the voltage-current profile after saturation. This is specifically for use within vehicle exhaust.
The inventive features focus on exploiting the transition region to voltage breakdown in the voltage-current profile to detect particle concentration in gases, with electrode spacing tailored to particle size, and include both specific sensor structures, detection methods, and application to vehicle emissions.
Stated Advantages
The sensor is robust and accurate.
It can be made as small as a conventional spark plug, meeting size requirements for current and future vehicles.
Provides real-time information about gas-particle mixture content.
Documented Applications
Installation in a vehicle to sense properties of engine exhaust, including testing emissions.
Detection of gas species and concentrations, and particle concentrations for emissions monitoring.
Determining the function of an exhaust aftertreatment device in a maintenance test by comparing response data to reference data.
Use for gas species detection in any gas.
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