Gas and particle sensor using voltage and current behavior between electrodes

Inventors

Aldayeh, Maher Abdulhamid • Abdul-Khalek, Imad Said

Assignees

Southwest Research Institute SwRI

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 and voltage breakdown between the electrodes while the gas is between the electrodes. Based on the response data, the controller determine a concentration of the gas or a concentration of particles within the gas.

Core Innovation

The invention provides a sensor for detecting properties of a gas, gas mixture, or a gas or gas mixture containing particles by utilizing the voltage and current behavior between two electrodes placed within a flow tube. A voltage is applied across the electrodes, and response data representing the current and voltage (including the voltage-current relationship and voltage breakdown) is measured as the gas flows between the electrodes. The measured response data enables the determination of the gas or particle concentration present in the medium.

The invention addresses the problem of accurately sensing gas composition, gas concentration, and particle concentration within gases or gas mixtures, including difficult-to-measure cases such as engine exhaust. Traditional methods based on Paschen's law and voltage breakdown behavior allow for detection of gases but may lack robustness or versatility for real-time analysis, especially with mixtures or the presence of particles. The described sensor overcomes these limitations by using distinct electrical signatures—voltage breakdown and voltage-current traces—to determine type and concentration of gases and particles.

Notably, the sensor includes features such as adjustable electrode gap distance (to accommodate different particle sizes), integration with supporting sensors to measure ambient parameters (temperature, flow, pressure), and the capability to perform real-time, in situ measurements. The system is suitable for robust deployment in applications such as vehicle exhaust emissions, offering flexible and sensitive detection in various environmental conditions.

Claims Coverage

There are three independent claims describing the main inventive features: a general gas/particle sensor, a detection method, and a vehicle emissions sensor.

The inventive features focus on: using a flow tube and electrodes to detect and distinguish gas and particle concentrations by analyzing current response prior to voltage breakdown, implementing a method for this detection, and specifically adapting these principles to a vehicle emissions sensor.

Stated Advantages

Documented Applications