Droplet sensors for fuel systems
Inventors
Moravec, Davis B. • QUAM, DARYL L. • Hall, Cullen E. • Tucker, Brian R. • Dallas, Andrew J.
Assignees
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Publication Number
US-12222271-B2
Publication Date
2025-02-11
Expiration Date
Abstract
A droplet detection system includes a sensing channel, such as a microfluidic channel, configured to receive a flow of fluid that may contain one or more liquid droplets dispersed in the fluid. The cross-sectional area of the sensing channel maybe configured to allow droplets of a predetermined size to flow through the channel one at a time. A light source, a light aperture, and a light detector are positioned outside the sensing channel, which use light in a selected frequency band that has a substantially different absorbance for the liquid compared to the fluid. Liquid droplets may be detected and characterized using a signal from the light detector.
Core Innovation
A droplet sensor system includes a microfluidic sensing channel configured to receive a flow of a first fluid and a second fluid dispersed in the first fluid, where the second fluid has a different composition than the first fluid. The microfluidic sensing channel is sized and arranged to pass droplets one-at-a-time through a defined sensing area/volume so that dispersed droplets can be detected separately from the surrounding fluids.
Light-based droplet detection is performed using a light source that directs a light beam in a frequency band along a path through the microfluidic channel. The frequency band is selected to have a higher absorbance by the second fluid than by the first fluid, and an aperture element defines a light aperture positioned in the path of the light beam.
A light detector positioned to receive the beam after passing through the microfluidic channel and the light aperture provides a signal representing an amount of light in the frequency band that remains after transmission. A controller processes the detector signal to determine whether the second fluid is in droplet form, including determining an amount of second liquid in droplet form per unit volume excluding second fluid dissolved in the first fluid, and determining droplet rate and droplet size from pulse/threshold analysis of the signal.
The system further supports vehicle engine fuel line integration by placing the microfluidic channel in parallel fluid communication with a main flow of the vehicle engine fuel line for water-in-fuel droplet sensing.
Claims Coverage
The independent claim covers a microfluidic droplet sensing system with 10 inventive features, centered on a frequency band with higher absorbance by the dispersed second fluid than by the surrounding first fluid, a defined light aperture, and a detector signal analyzed by a controller to determine whether the second fluid is in droplet form. Vehicle engine fuel line integration is included through parallel fluid communication, with dependent features refining droplet amount, rate, size, sensing-area geometry, and fuel-line components.
Microfluidic channel with dispersed second fluid
A microfluidic channel configured to receive a flow of a first fluid and a second fluid dispersed in the first fluid, wherein the second fluid has a different composition than the first fluid.
Frequency band selected for higher absorbance by second fluid
A light source configured to direct a light beam in a frequency band along a path through the microfluidic channel, wherein the frequency band is selected to have a higher absorbance by the second fluid than by the first fluid.
Light aperture defining a light aperture in the beam path
An aperture element defining a light aperture positioned in the path of the light beam from the light source.
Detector signal representing remaining light after microfluidic channel
A light detector positioned to receive the light beam in a sensing area after passing through the microfluidic channel and the light aperture, the light detector configured to provide a signal representing an amount of light in the frequency band that remains after passing through the microfluidic channel.
Controller determining droplet form from remaining-light signal
A controller operably coupled to the light detector and configured to determine whether the second fluid is in droplet form based on the signal.
Parallel fluid communication with vehicle engine fuel line
The microfluidic channel is in parallel fluid communication with a main flow of a vehicle engine fuel line.
Droplet amount excluding dissolved second fluid per unit volume
The controller determines an amount of second liquid in droplet form per unit volume of first fluid from the signal, excluding second fluid dissolved in the first fluid.
Droplet rate and droplet size via pulse and threshold characteristics
The controller determines droplet rate or droplet size from signal pulse characteristics and threshold crossing features, including pulse magnitude, pulse width, first threshold signal level, a minimum size droplet in the sensing area, a second threshold signal level, a droplet that fills the sensing area, and a threshold signal level crossing rate.
Droplet size constraint using equivalent spherical diameter
The controller detects a droplet of the second liquid having equivalent volume to a spherical droplet with a diameter in the range from 10 up to 1000 micrometers.
Geometric sensing constraints for channel cross-sectional area and aperture width
The microfluidic channel defines a cross-sectional area less than 1 mm2, and the light aperture has a width less than 1 mm to define the sensing area.
Overall claim coverage centers on microfluidic droplet sensing using a chosen frequency band with higher absorbance by the dispersed second fluid, an aperture-defined sensing path, and a detector signal representing remaining light. The controller determines whether the second fluid is in droplet form and, in dependent claim refinements, quantifies droplet amount while excluding dissolved second fluid, and derives droplet rate and droplet size using pulse/threshold signal analysis, with additional constraints on droplet size range and sensing-area geometry. Vehicle engine fuel line use is incorporated through parallel fluid communication.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Water-in-fuel droplet sensing.
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