Bubble sensing system and related signal processing

Abstract

Embodiments herein relate to a system for detecting bubbles in a fluid. In an embodiment, a fluidic system ventilation detector having an optical bubble sensor is included. The optical bubble sensor may include a light source, a light detector, and a sensor controller. The sensor controller may be in signal communication with the light detector and may be configured to detect bubbles based on a signal received from the light detector. The sensor controller may be further configured to estimate a throughput of the fluid based on the detected bubbles. Other embodiments are also included herein.

Description

[0001] This application was filed on March 15, 2023 as a PCT international patent application in the name of Donaldson Company, a U.S. corporation (designated applicant in all countries) and U.S. citizens Davis B. Moravec, Michael J. Cronin, Danny W. Miller, Chad M. Goltzman, Mikayla A. Yoder, and Bradly G. Hauser, a U.S. citizen (designated inventors in all countries), and claims priority to U.S. Provisional Application No. 63 / 320,557 filed on March 16, 2022 and U.S. Patent Application No. 18 / 115,464 filed on February 28, 2023, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] Embodiments herein relate to systems for detecting bubbles in fluids and related systems and methods. Background Art

[0003] Air bubbles can be present in a variety of fluids used in equipment, such as fuel, hydraulic fluid, coolant, lubricant, etc. The presence of air bubbles can have a variety of reasons, including leaks in the reservoir or tank, contamination, cavitation, turbulence or mixing. Unfortunately, air bubbles can cause a variety of problems. For example, in hydraulic systems, air bubbles can cause fluid foaming, erratic actuator movement, and knocking or knocking noises. In fuel systems, air bubbles can cause erratic engine operation or even damage. Summary of the invention

[0004] Embodiments herein relate to systems for detecting bubbles in a fluid and related systems and methods. In a first aspect, a fluid system ventilation detector having an optical bubble sensor may be included. The optical bubble sensor may include a light source, a light detector, and a sensor controller. The sensor controller may be in signal communication with the light detector and may be configured to detect bubbles based on signals received from the light detector and estimate the ventilation of the fluid based on the detected bubbles.

[0005] In a second aspect, in addition to one or more of the foregoing or following aspects, or in an alternative to some aspects, the sensor controller may be configured to distinguish between bubbles and water droplets in the fluid based on at least one of peak magnitude and peak width.

[0006] In a third aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the sensor controller can be configured to distinguish between bubbles and water drops based on a ratio of peak magnitude to peak width.

[0007] In a fourth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the sensor controller may be configured to distinguish between bubbles and water drops based on peak magnitude.

[0008] In a fifth aspect, in addition to one or more of the foregoing or following aspects, or in an alternative to some aspects, the sensor controller can be configured to distinguish between bubbles and water droplets based on the magnitude of a reflection peak preceding a peak produced by absorbance, refraction and / or scattering.

[0009] In a sixth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the fluid system ventilation detector may be an on-board sensing system.

[0010] In a seventh aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the optical bubble sensor can be configured to be disposed downstream of the filter and upstream of the fluid pump.

[0011] In an eighth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the optical bubble sensor may be configured to be connected to a pipeline that flows fluid out of a fluid storage tank.

[0012] In a ninth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the optical bubble sensor can be configured as a kidney-shaped loop connected to a fluid storage tank.

[0013] In a tenth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the optical bubble sensor can be configured to be disposed at a region under vacuum pressure within the fluid system.

[0014] In an eleventh aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the optical bubble sensor may further include a sampling channel, wherein the sampling channel may be in fluid communication with a fluid line of the vehicle.

[0015] In a twelfth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the light source can be configured to emit light into the sampling channel.

[0016] In a thirteenth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the light source can be configured to emit near infrared light, ultraviolet light, and / or visible spectrum light.

[0017] In a fourteenth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the fluid system ventilation detector can be configured to generate an alarm when a detected bubble count exceeds a threshold value within a certain period of time.

[0018] In a fifteenth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the fluid system ventilation detector can be configured to generate an alarm when the volume of detected bubbles exceeds a threshold.

[0019] In a sixteenth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the fluid system ventilation detector can be configured to track the count, size distribution and / or volume of detected bubbles over time.

[0020] In a seventeenth aspect, the present invention may include a method of detecting aeration of a fluid system. The method may include detecting bubbles based on a signal received from a light detector; and estimating aeration of the fluid based on the detected bubbles.

[0021] In an eighteenth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the method may further include distinguishing between bubbles and water droplets in the fluid based on at least one of peak magnitude and peak width.

[0022] In a nineteenth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the method may further include distinguishing between bubbles and water droplets based on a ratio of peak magnitude to peak width.

[0023] In a twentieth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the method may further include distinguishing between bubbles and water droplets based on the peak magnitude.

[0024] In a twenty-first aspect, in addition to one or more of the foregoing or following aspects, or in an alternative to some aspects, the method may further include distinguishing between bubbles and water droplets based on the magnitude of a reflection peak preceding a peak produced by absorbance, refraction and / or scattering.

[0025] In a twenty-second aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the light detector can be configured to be disposed downstream of the filter and upstream of the fluid pump.

[0026] In a twenty-third aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the light detector may be configured to be connected to a pipeline that flows fluid out of a fluid storage tank.

[0027] In a twenty-fourth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the light detector can be configured as a kidney-shaped loop connected to a fluid storage tank.

[0028] In a twenty-fifth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the light detector can be configured to be disposed at a region under vacuum pressure within the fluid system.

[0029] In a twenty-sixth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the method may further include emitting light into the sampling channel.

[0030] In a twenty-seventh aspect, in addition to or in the alternative to one or more of the foregoing or following aspects, emitting light into the sampling channel comprises emitting near infrared light, ultraviolet light, and / or visible spectrum light.

[0031] In a twenty-eighth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the method may further include generating an alarm when the bubble count detected within a certain period of time exceeds a threshold.

[0032] In a twenty-ninth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the method may further include generating an alarm when the detected bubble volume exceeds a threshold.

[0033] In a thirtieth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the method may further include tracking the count, size distribution and / or volume of detected bubbles over time.

[0034] In a thirty-first aspect, a hydraulic system bubble detector having an optical bubble sensor may be included. The optical bubble sensor may include a light source, a light detector, and a sensor controller. The sensor controller may be in signal communication with the light detector and may be configured to detect bubbles based on signals received from the light detector and estimate the amount of air in the hydraulic fluid line based on the detected bubbles.

[0035] In a thirty-second aspect, in addition to one or more of the foregoing or following aspects, or in an alternative to some aspects, the sensor controller may be configured to distinguish between bubbles and water droplets in the fluid based on at least one of peak magnitude and peak width.

[0036] In a thirty-third aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the sensor controller can be configured to distinguish between bubbles and water droplets based on a ratio of peak magnitude to peak width.

[0037] In a thirty-fourth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the sensor controller can be configured to distinguish between bubbles and water drops based on peak magnitude.

[0038] In aspect thirty-fifth, in addition to one or more of the foregoing or following aspects, or in an alternative to some aspects, the sensor controller can be configured to distinguish between bubbles and water droplets based on the magnitude of a reflection peak preceding a peak produced by absorbance, refraction and / or scattering.

[0039] In a thirty-sixth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the hydraulic system bubble detector may be an on-board sensing system.

[0040] In a thirty-seventh aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the optical bubble sensor can be configured to be disposed downstream of the filter and upstream of the fluid pump.

[0041] In a thirty-eighth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the optical bubble sensor can be configured to connect to a return line back to the hydraulic fluid storage tank.

[0042] In a thirty-ninth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the optical bubble sensor can be configured to be connected to a pipeline that flows fluid out of a hydraulic fluid storage tank.

[0043] In a fortieth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the optical bubble sensor can be configured as a kidney loop connected to a hydraulic fluid storage tank.

[0044] In a forty-first aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the optical bubble sensor can be configured to be disposed at a region under vacuum pressure within the hydraulic fluid system.

[0045] In a 42nd aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the optical bubble sensor may further include a sampling channel, wherein the sampling channel may be in fluid communication with a hydraulic line of the vehicle.

[0046] In a forty-third aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the light source can be configured to emit light into the sampling channel.

[0047] In a forty-fourth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the hydraulic system bubble detector can be configured to generate an alarm when a detected bubble count exceeds a threshold within a certain period of time.

[0048] In a forty-fifth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the hydraulic system bubble detector can be configured to generate an alarm when the volume of detected bubbles exceeds a threshold.

[0049] In a forty-sixth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the hydraulic system bubble detector can be configured to track the count, size distribution and / or volume of detected bubbles over time.

[0050] In a forty-seventh aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the light source can be configured to emit near infrared light, ultraviolet light and / or visible spectrum light.

[0051] In a forty-eighth aspect, a method of estimating the amount of air in a hydraulic fluid line may be included. The method may include detecting air bubbles based on a signal received from a light detector; and estimating the amount of air in the hydraulic fluid line based on the detected air bubbles.

[0052] In a forty-ninth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the method may further include distinguishing between bubbles and water droplets in the fluid based on at least one of the peak magnitude and the peak width.

[0053] In a fiftieth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the method may further include distinguishing between bubbles and water droplets based on a ratio of peak magnitude to peak width.

[0054] In the fifty-first aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the method may further include distinguishing between bubbles and water droplets based on peak magnitude.

[0055] In aspect 52, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the method may further include distinguishing between bubbles and water droplets based on the magnitude of a reflection peak preceding a peak produced by absorbance, refraction and / or scattering.

[0056] In a fifty-third aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the method may further include emitting light into the sampling channel.

[0057] In a fifty-fourth aspect, in addition to one or more of the foregoing or following aspects, or in an alternative of some aspects, wherein emitting light into the sampling channel comprises emitting near infrared light, ultraviolet light, and / or visible spectrum light.

[0058] In a fifty-fifth aspect, in addition to one or more of the preceding or following aspects, or in the alternative of some aspects, the method may further include generating an alarm when the bubble count detected within a certain period of time exceeds a threshold.

[0059] In a fifty-sixth aspect, in addition to one or more of the preceding or following aspects, or in the alternative of some aspects, the method may further include generating an alarm when the detected bubble volume exceeds a threshold.

[0060] In a fifty-seventh aspect, in addition to one or more of the preceding or following aspects, or in the alternative of some aspects, the method may further include tracking the count, size distribution and / or volume of detected bubbles over time.

[0061] In a fifty-eighth aspect, a pressure sensing system having an optical bubble sensor may be included. The optical bubble sensor may include a light source, a light detector, and a sensor controller. The sensor controller may be in signal communication with the light detector and may be configured to detect bubbles based on signals received from the light detector and estimate an amount of pressure in the fluid line based on the detected bubbles.

[0062] In a fifty-ninth aspect, in addition to one or more of the foregoing or following aspects, or in an alternative to some aspects, the sensor controller can be configured to distinguish between bubbles and water droplets in the fluid based on at least one of the peak magnitude and the peak width.

[0063] In a sixtieth aspect, in addition to one or more of the foregoing or following aspects, or in an alternative to some aspects, the sensor controller can be configured to distinguish between bubbles and water droplets based on a ratio of peak magnitude to peak width.

[0064] In a sixty-first aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the sensor controller can be configured to distinguish between bubbles and water drops based on peak magnitude.

[0065] In aspect sixty-two, in addition to one or more of the foregoing or following aspects, or in an alternative to some aspects, the sensor controller can be configured to distinguish between bubbles and water droplets based on the magnitude of a reflection peak preceding a peak produced by absorbance, refraction and / or scattering.

[0066] In a sixty-third aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the pressure sensing system may be a vehicle-mounted sensing system.

[0067] In a sixty-fourth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the optical bubble sensor can be configured to be disposed downstream of the filter and upstream of the fluid pump.

[0068] In a sixty-fifth aspect, in addition to one or more of the foregoing or following aspects, or in an alternative to some aspects, it may further include a sampling channel, wherein the sampling channel may be in fluid communication with a fluid pipeline of the vehicle.

[0069] In a sixty-sixth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the light source can be configured to emit light into the sampling channel.

[0070] In a sixty-seventh aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the pressure sensing system can be configured to generate an alarm when the count, size distribution and / or volume of detected bubbles within a certain time period exceeds a threshold.

[0071] In a sixty-eighth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the pressure sensing system can be configured to track the count, size distribution and / or volume of detected bubbles over time.

[0072] In a sixty-ninth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the light source can be configured to emit near infrared light, ultraviolet light, and / or visible spectrum light.

[0073] In a seventieth aspect, a method of estimating an amount of pressure in a fluid line may be included. The method may include detecting bubbles based on a signal received from a light detector; and estimating the amount of pressure in the fluid line based on the detected bubbles.

[0074] In the seventy-first aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the method may further include distinguishing between bubbles and water droplets in the fluid based on at least one of the peak magnitude and the peak width.

[0075] In a seventy-second aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the method may further include distinguishing between bubbles and water droplets based on a ratio of peak magnitude to peak width.

[0076] In a seventy-third aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the method may further include distinguishing between bubbles and water droplets based on the peak magnitude.

[0077] In aspect seventy-four, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the method may further include distinguishing between bubbles and water droplets based on the magnitude of a reflection peak preceding a peak produced by absorbance, refraction and / or scattering.

[0078] In a seventy-fifth aspect, in addition to or in the alternative of one or more of the preceding or following aspects, the method may further include emitting light into the sampling channel.

[0079] In a seventy-sixth aspect, in addition to one or more of the foregoing or following aspects, or in an alternative embodiment of some aspects, wherein emitting light into the sampling channel includes emitting near infrared light, ultraviolet light and / or visible spectrum light.

[0080] In a seventy-seventh aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the method may further include generating an alarm when the bubble count detected within a certain period of time exceeds a threshold.

[0081] In a seventy-eighth aspect, in addition to one or more of the preceding or following aspects, or in the alternative of some aspects, the method may further include tracking the count, size distribution and / or volume of detected bubbles over time.

[0082] In a seventy-ninth aspect, a filter restriction sensing system having an optical bubble sensor may be included. The optical bubble sensor may include a light source, a light detector, and a sensor controller. The sensor controller may be in signal communication with the light detector and may be configured to evaluate a signal received from the light detector, detect bubbles based on the signal received from the light detector, and generate an estimate of the degree of restriction of a liquid filter upstream of the light detector based on the detected bubbles.

[0083] In an eightieth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the optical bubble sensor can be configured to be disposed at a region under vacuum pressure within the fuel system.

[0084] In an eighty-first aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the optical bubble sensor can be configured to be disposed at an area under vacuum pressure within a vehicle fuel system.

[0085] In an eighty-second aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the optical bubble sensor can be configured to be disposed at an area under vacuum pressure within the hydraulic system.

[0086] In an eighty-third aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the optical bubble sensor can be configured to be disposed downstream of the filter and upstream of the fluid pump.

[0087] In an eighty-fourth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the optical bubble sensor can be configured to be disposed downstream of the filter and upstream of the hydraulic fluid pump.

[0088] In an eighty-fifth aspect, in addition to one or more of the foregoing or following aspects, or in an alternative to some aspects, the sensor controller can be configured to distinguish between bubbles and water droplets in the fluid based on at least one of peak magnitude and peak width.

[0089] In an eighty-sixth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the sensor controller can be configured to distinguish between bubbles and water droplets based on a ratio of peak magnitude to peak width.

[0090] In an eighty-seventh aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the sensor controller can be configured to distinguish between bubbles and water droplets based on peak magnitude.

[0091] In aspect 88, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the sensor controller can be configured to distinguish between bubbles and water droplets based on the magnitude of a reflection peak preceding a peak produced by absorbance, refraction and / or scattering.

[0092] In an eighty-ninth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the filter restriction sensing system may be an on-board sensing system.

[0093] In a ninetieth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the filter restriction sensing system may be a fuel filter restriction sensing system.

[0094] In a ninety-first aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the filter restriction sensing system may be a hydraulic fluid filter restriction sensing system.

[0095] In a ninety-second aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the filter restriction sensing system may further include a sampling channel, wherein the sampling channel may be in fluid communication with a fluid line of the vehicle.

[0096] In a ninety-third aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the light source may be configured to emit light into the sampling channel.

[0097] In a ninety-fourth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the light source can be configured to emit near infrared light, ultraviolet light, and / or visible spectrum light.

[0098] In a ninety-fifth aspect, additionally or in the alternative to one or more of the foregoing or following aspects, the inlet of the sampling channel can be positioned along a curved portion of the fluid flow channel.

[0099] In a ninety-sixth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, an inlet of the sampling channel is at least partially facing upward relative to the direction of gravity.

[0100] In a ninety-seventh aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the filter restriction sensing system can be configured to generate an estimate of the degree of restriction of the fluid filter upstream of the light detector based on one or more characteristics of the detected bubbles.

[0101] In a ninety-eighth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the characteristics of the detected bubbles may include at least one item selected from the group consisting of: average bubble size, maximum bubble size, bubble count, and percentage of bubble volume to total fluid volume.

[0102] In a ninety-ninth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the filter restriction sensing system can be further configured to generate a restriction estimate using fluid flow through the filter.

[0103] In a hundredth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, a filter restriction sensing system can be configured to determine end of life of a fluid filter based on an estimated degree of restriction of the fluid filter.

[0104] In one hundred and first aspects, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the filter restriction sensing system can be configured to generate an alarm when the count, size distribution and / or volume of detected bubbles over a certain time period exceeds a threshold.

[0105] In a one hundred and second aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, a filter restriction sensing system can be configured to track counts, size distributions, and / or volumes of detected bubbles over time.

[0106] In a one-hundred-and-third aspect, a method of determining a degree of restriction of a filter may be included, the method comprising evaluating a signal received from a light detector, detecting bubbles based on the signal received from the light detector, and generating an estimate of the degree of restriction of a liquid filter upstream of the light detector based on the detected bubbles.

[0107] In a one hundred and fourth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, a light detector may be disposed at a region within the fuel system that is under vacuum pressure.

[0108] In a one-hundred-fifth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, a light detector may be disposed at a region under vacuum pressure within the hydraulic system.

[0109] In a one hundred sixth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, a light detector may be disposed within the hydraulic system downstream of a filter and upstream of a fluid pump.

[0110] In a one hundred and seventh aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, a light detector may be disposed within the hydraulic system downstream of a filter and upstream of a hydraulic fluid pump.

[0111] In a one-hundred and eighth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the method may further include distinguishing between bubbles and water droplets in the fluid based on at least one of peak magnitude and peak width.

[0112] In a one hundred and ninth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the method may further include distinguishing between bubbles and water droplets based on a ratio of peak magnitude to peak width.

[0113] In a one hundred and tenth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the method may further include distinguishing between bubbles and water droplets based on peak magnitude.

[0114] In a one hundred and eleventh aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the method may further include distinguishing between bubbles and water droplets based on the magnitude of a reflection peak preceding a peak produced by absorbance, refraction and / or scattering.

[0115] In a one hundred twelfth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the method may further include emitting light into the sampling channel.

[0116] In a thirteenth aspect, in addition to or in the alternative to one or more of the foregoing or following aspects, emitting light into the sampling channel comprises emitting near infrared light, ultraviolet light, and / or visible spectrum light.

[0117] In a fourteenth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the method may further include generating an estimate of the degree of restriction of a fluid filter upstream of the optical detector based on one or more characteristics of the detected bubbles.

[0118] In a fifteenth aspect, in addition to one or more of the foregoing or following aspects, or in an alternative to some aspects, generating an estimate of the degree of restriction of a fluid filter upstream of a light detector based on one or more characteristics of detected bubbles includes using fluid flow through the filter to generate the estimate of the degree of restriction.

[0119] In a sixteenth aspect, in addition to or in the alternative to one or more of the foregoing or following aspects, the method may further include determining an end of life of the fluid filter based on an estimated degree of restriction of the fluid filter.

[0120] In a one-hundred and seventeenth aspect, in addition to one or more of the foregoing or following aspects, or in the alternative of some aspects, the method may further include generating an alarm when a bubble count detected within a certain period of time exceeds a threshold.

[0121] In a one hundred and eighteenth aspect, in addition to or in the alternative of one or more of the foregoing or following aspects, the method may further comprise tracking the count, size distribution and / or volume of detected bubbles over time.

[0122] The present disclosure is an overview of some of the teachings of this application and is not intended to be an exclusive or exhaustive treatment of this subject matter. Further details are found in the specific embodiments and the appended claims. Other aspects will be apparent to those skilled in the art after reading and understanding the following specific embodiments and viewing the accompanying drawings that form a part of the specific embodiments, and each of these aspects should not be considered to have a limiting meaning. The scope of this article is limited by the appended claims and their legal equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0123] Various aspects may be more fully understood in conjunction with the following drawings (figures), in which:

[0124] Figure 1 is a schematic diagram of a fuel system according to various embodiments herein.

[0125] Figure 2 is a schematic diagram of a hydraulic system according to various embodiments herein.

[0126] Figure 3 is a schematic diagram of a bubble sensing system according to various embodiments herein.

[0127] Figure 4 yes Figure 3 Schematic diagram of a portion of the bubble sensing system.

[0128] Figure 5 is a schematic diagram of a portion of a bubble sensing system according to various embodiments herein.

[0129] Figure 6 is a graph of potential versus time for a sensing system according to various embodiments herein.

[0130] Figure 7 is a schematic diagram of a portion of a bubble sensing system according to various embodiments herein.

[0131] Figure 8 is a graph of potential versus time for a sensing system according to various embodiments herein.

[0132] Fig. 9 is a schematic diagram of a portion of a bubble sensing system according to various embodiments herein.

[0133] Fig.10 is a graph of potential versus time for a sensing system according to various embodiments herein.

[0134] Fig.11 is a schematic diagram of a bubble sensing system according to various embodiments herein.

[0135] Fig.12 is a schematic diagram of a bubble sensing system according to various embodiments herein.

[0136] Fig.13 is a block diagram of components of a bubble sensing system according to various embodiments herein.

[0137] Fig.14 is a schematic diagram of a portion of a bubble sensing system according to various embodiments herein.

[0138] Fig.15 is a graph of potential versus time for a sensing system according to various embodiments herein.

[0139] Fig.16 is a histogram showing the peak counts of water droplets and bubbles at different absorbance levels in the system herein.

[0140] Fig.17 is a graph showing the relationship between the absorbance and the peak width of water droplets and bubbles in the system herein.

[0141] Although the embodiments are susceptible to various modifications and alternative forms, the details have been illustrated by examples and drawings and will be described in detail. However, it should be understood that the scope of this article is not limited to the specific aspects described. On the contrary, the purpose is to cover modifications, equivalents and alternatives that fall within the spirit and scope of this article. DETAILED DESCRIPTION

[0142] As discussed above, bubbles in a fluid may cause a variety of problems. Therefore, it may be desirable to detect and / or track the presence of bubbles in a system. Further, the presence of bubbles may provide an indication of a possible problem with the system, such as a leak or a need for filter system repair. In some cases, the presence of bubbles may also be used as an indicator of pressure, as the presence of bubbles may be correlated to pressure (e.g., when a fluid is under vacuum pressure, dissolved air may form bubbles). Further, pressure may be correlated to the degree of restriction of a filter.

[0143] Embodiments herein may include a fluid system ventilation detector including an optical bubble sensor. The optical bubble sensor may include a light source, a light detector, and a sensor controller. The sensor controller may communicate signals with the light detector. The sensor controller may be configured to detect bubbles based on signals received from the light detector and estimate the ventilation of the fluid based on the detected bubbles.

[0144] Embodiments herein may include a bubble sensing system that can detect the presence of bubbles in a fluid. In some embodiments, the sensing system can be mounted specifically on a vehicle. By being mounted on a vehicle, the system can provide useful information to vehicle operators, fleet controllers, etc. to support the operation of the vehicle while mitigating potential damage. For example, the amount of bubbles in the fluid of a vehicle can result in recommendations made by the system related to maintenance of the vehicle, including the frequency of maintenance, the type of fluid filter used, etc. In some scenarios, if the amount of bubbles in the fluid rises above a threshold level, it is recommended to stop the operation of the vehicle until maintenance service can be performed.

[0145] Embodiments herein may also include a hydraulic system bubble detector. The bubble detector may include an optical bubble sensor. The optical bubble sensor may include a light source, a light detector, and a sensor controller. The sensor controller may be in signal communication with the light detector. The sensor controller may be configured to detect bubbles based on signals received from the light detector and estimate the amount of air in the hydraulic fluid line based on the detected bubbles.

[0146] Embodiments herein may also include a pressure sensing system including an optical bubble sensor. Pressure may affect bubbles (other things being equal, the lower the pressure, the larger the bubble volume), so information about the bubbles may be used to sense pressure. The optical bubble sensor may include a light source, a light detector, and a sensor controller. The sensor controller may be in signal communication with the light detector and may be configured to detect bubbles based on signals received from the light detector and estimate the amount of pressure in the fluid line based on the detected bubbles.

[0147] Embodiments herein may also include a filter restriction sensing system including an optical bubble sensor. Filter restriction may be reflected in a pressure drop across the filter, thereby affecting the pressure upstream and downstream of the filter. Pressure may affect bubbles (other things being equal, the lower the pressure, the larger the bubble volume), so information about the bubbles may be used to sense filter restriction. The optical bubble sensor may include a light source, a light detector, and a sensor controller. The sensor controller may communicate signals with the light detector. The sensor controller may be configured to evaluate a signal received from the light detector, detect bubbles based on the signal received from the light detector, and generate an estimate of the degree of restriction of a liquid filter (with or without other components such as a pump, upstream, downstream, between, or on the other side of the light detector, etc.) in fluid communication with the light detector based on the detected bubbles.

[0148] In various embodiments, the bubble sensing system herein may include a light source, a light detector, and a sensor controller. The sensor controller may be in signal communication with the light detector. The sensor controller may be configured to evaluate the signal received from the light detector, identify bubbles based on the signal received from the light detector, record information about the identified bubbles, and generate an estimate of the amount of air or bubbles in the fluid.

[0149] In various embodiments herein, the bubble sensing system can distinguish between bubbles and water droplets to allow for a more accurate measurement of the bubbles. In various embodiments, the sensor controller can be configured to: evaluate the signal received from the light detector; distinguish between bubbles and water droplets based on the signal received from the light detector; record information about the bubbles; and generate an estimate of the amount of air or bubbles in the fluid.

[0150] Bubbles can occur in many different systems of a machine or vehicle. For example, bubbles can occur in the fuel system. Figure 1 , a schematic diagram of a fuel system 100 is shown according to various embodiments herein. The fuel system 100 may include various components such as a fuel tank 102, a fuel line 104, and a fuel filter system 108. The fuel system 100 may also include a fuel pump 112, a fuel rail 114, and a plurality of fuel injectors 116. The fuel line 104 includes an upstream 106 side (e.g., upstream of the fuel filter system 108) and a downstream 110 side.

[0151] The bubble sensing system herein may be installed at various points along the fuel system 100. In some embodiments, the bubble sensing system (or components thereof) may be installed along the fuel line 104. In various embodiments, the bubble sensing system may be installed upstream 106 of the fuel filter. In various embodiments, the bubble sensing system may be installed downstream 110 of the fuel filter. In various embodiments, the bubble sensing system may be installed on or in a fuel filter head (described further below).

[0152] In some embodiments, the system can also be configured to receive information about the fuel level in the fuel tank 102. For example, in some embodiments, the system can cross-reference the fuel level information with the recorded information about the detected bubbles. In some cases, the system can obtain the fuel level data directly from the sensor associated with the fuel tank. In some embodiments, the system can obtain the fuel level data from a vehicle data network such as CANBus. "CANBus" refers to a vehicle data bus standard designed to allow devices and electronic control units to communicate with each other. Many vehicles include a CANBus network, and communication with the CANBus network can provide many different types of data. For example, docking with the CANBus network can provide one or more of fuel level data, engine RPM data, engine operating hours data, odometer data, engine / vehicle temperature data, fuel consumption data, fuel system data, ambient temperature data, geolocation and / or altitude data, fuel flow, etc.

[0153] It should be understood that Figure 1 The fuel system shown in is only one example of a fuel system in which the bubble detection system herein may work, and the range of compatible fuel systems contemplated herein may include many different variations. For example, some fuel systems may include a dual filter system with a lift / transfer pump between the two filters. Thus, Figure 1 The fuel filter system 108 may reflect two filters with a lift / delivery pump disposed therebetween. In such a system, the bubble sensing system may be configured to detect bubbles located downstream of the first filter but upstream of the lift / delivery pump and the second filter (e.g., an area with vacuum pressure). However, the bubble sensing system may also detect bubbles in other locations. Additionally, embodiments of the bubble sensing systems for fuel systems herein may include those bubble sensing systems that operate with fuel systems having any number of fuel filters.

[0154] Air bubbles can also occur in other types of systems with fluid lines, such as hydraulic systems. Figure 2, a schematic diagram of a hydraulic system 200 is shown according to various embodiments herein. It should be understood that in many embodiments of the hydraulic system, Figure 2 The various filters shown may not actually be all present. System 200 includes a hydraulic cylinder 202. Hydraulic cylinder 202 includes a cylinder barrel 206 and a piston rod 204. Hydraulic fluid flows through system 200 under the control of control unit 208 and passes through hydraulic fluid line 226. A certain amount of hydraulic fluid is stored in tank 214 and passes through coarse filter 218, then flows through hydraulic fluid line 226 and reaches low pressure (or suction pressure) filter 220, and then reaches hydraulic fluid pump 222. The hydraulic fluid is then pumped to medium or high pressure filter 224, then passes through control unit 208, and finally enters hydraulic cylinder 202. On the return path, the hydraulic fluid then passes through control unit 208, then passes through return line filter 210, then passes through in-tank return filter 212 and enters tank 214. Tank 214 may include vent 216. In some embodiments, hydraulic system 200 may also include a kidney-shaped circuit system (not shown in this view). The kidney loop system may include a pump and a filter and may be operable to pump fluid from the reservoir 214 through the filter and back to the reservoir 214 such that the kidney loop functions to clean the fluid within the reservoir 214 .

[0155] The bubble sensing system of this article can be installed at various points along the hydraulic system 200. In some embodiments, the bubble sensing system (or its components) can be installed along the hydraulic fluid line 226. In various embodiments, the bubble sensing system can be installed in the hydraulic system or on the hydraulic system at an area under vacuum pressure. In various embodiments, the bubble sensing system can be installed in the hydraulic system or on the hydraulic system downstream of the filter and upstream of the fluid pump. In various embodiments, the bubble sensing system can be installed downstream of the filter (such as any filter in the hydraulic system, or particularly the low pressure or suction pressure filter 220) and upstream of the hydraulic fluid pump. However, it should be understood that the bubble sensing system (or its components) herein can be installed upstream or downstream or at other locations of any fluid filter described herein. In various embodiments, the bubble sensing system can be installed on or in the filter head.

[0156] Reference now Figure 3 , shows a schematic diagram of a bubble sensing system 304 according to various embodiments of the present invention. As previously described, in some embodiments, the bubble sensing system 304 can be configured to be installed on a vehicle. However, in other embodiments, it can be installed on a fixed device such as a generator. Figure 3 Fluid lines 310 of a vehicle are shown. Figure 3A bubble sensing system 304 is shown. The bubble sensing system 304 includes a flow channel 302. The flow channel 302 can be in fluid communication with a fluid line 310 of a vehicle or other device. The flow channel 302 is typically a known ratio of the diameter and / or cross-sectional area of ​​the fluid line 310 (e.g., 1:1, 1:5, 1:10, 1:25, 1:50, 1:100, 1:200, 1:500, 1:1000, or less, or a range between any of these ratios). Thus, a portion of the fluid flowing through the fluid line 310 can enter the flow channel 302 to be tested by the bubble sensing system 304.

[0157] In various embodiments herein, data regarding flow rate may be used in combination with data regarding the number of bubbles detected and the size of the water droplets detected in order to estimate the total amount of bubbles in the fluid. It should be understood that at least two possible different fluid flow rates are considered when making such calculations. The first is the system fluid flow rate. The second is the sensor fluid flow rate, i.e., the flow through the sensor. Figure 3 The flow rate of the fluid in the flow channel 302 of the bubble sensing system 304 described in . The system fluid flow rate may vary due to a variety of factors, including the operating state and / or load of the system. The sensor flow rate is usually much lower than the system fluid flow rate. In some embodiments, the sensor flow rate can be 0.2mlpm (ml / min) to 10mlpm, 0.2mlpm (ml / min) to 5mlpm, 0.2mlpm (ml / min) to 2mlpm, or 0.8mlpm to 1.2mlpm. The sensor flow rate is related to the system flow rate, so when the system flow rate changes, the sensor flow rate will also change. Converting from one flow rate to another only requires applying a simple calibration or relationship. In some embodiments, the system can store data in a lookup table or similar data structure, correlating the sensor flow rate with different values ​​of the system flow rate, and then simply referencing the lookup table to convert between the two. In some embodiments, the data that associates the sensor flow rate with the system flow rate can be determined empirically.

[0158] In some embodiments, the bubble sensing system 304 also includes a flow sensor 306. Data from the flow sensor 306 can be used in combination with data about the number of bubbles detected and the size of the bubbles detected to estimate the total amount of air or bubbles in the fluid. In some embodiments, the flow sensor 306 can be positioned so that it detects a sensor flow. When calculating / estimating the total amount of bubbles in the fluid, the sensor flow can be determined, and this information can then be used in combination with data about the number of bubbles detected and the size of the bubbles detected to estimate the total amount of bubbles in the fluid. However, in some cases, the flow sensor can be positioned along the fluid line so that the flow obtained is the system fluid flow. In such a case, the system fluid flow can be converted to a sensor flow as discussed above.

[0159] In some embodiments, data about the system fluid flow rate can be obtained in other ways, and thus the flow sensor 306 can be omitted. For example, in some embodiments, the pressure difference (dP) can be used to calculate / estimate the flow rate. The flow rate estimated in this way can be the system flow rate or the sensor flow rate. The system can include a differential pressure sensor, and then calculate the flow rate based on the relationship between dP and the flow rate and the assumption of laminar flow (within the sensor channel) and the knowledge of fluid properties. In some embodiments, when evaluating the flow rate of the mainstream channel (system flow), a turbulence model can also be used as part of the flow calculation. As another example, in some embodiments, the bubble sensing system 304 can obtain information about the fluid flow rate (or a piece of information from which the fluid flow rate can be obtained or otherwise estimated) from the vehicle data network 308. In some embodiments, the vehicle data network 308 can be a CANBUS network. However, in other embodiments, the vehicle data network 308 can be another type of network that is wired or wireless. In various embodiments, the bubble sensing system 304 can be configured to send information about the identified bubbles to the vehicle data network 308.

[0160] In some embodiments, the components of the bubble sensing system can be arranged so that bubbles enter the inlet 312 due to their buoyancy. This may result in an increase in the amount of bubbles entering the inlet 312. For example, in some embodiments, the inlet 312 of the sampling channel is positioned along a curved portion of the fluid flow channel. In some embodiments, the inlet 312 of the sampling channel is at least partially upward relative to the direction of gravity. In some embodiments, a pipeline feature can be included to achieve isokinetic sampling.

[0161] Reference now Figure 4 , showing Figure 3 Schematic diagram of a portion of the bubble sensing system. Figure 4A bubble sensing system 304 is shown that includes a flow channel 302. Fluid can flow into the flow channel from a fuel line, a hydraulic fluid line, a lubricant line, a coolant line, etc. (or a component connected to any of them) of a system or vehicle. In some embodiments, the bubble sensing system 304 also includes a circulation pool 416. The circulation pool 416 can be transparent, partially transparent, or at least include a transparent portion, and can be formed of various materials such as glass or polymers. The circulation pool 416 (or another conduit temporarily used for light transmission) can be connected to the flow channel 302. Therefore, the fluid can pass through the flow channel 302.

[0162] The bubble sensing system 304 includes a light source 408. The bubble sensing system 304 also includes a source light guide 410. In some embodiments, the bubble sensing system 304 also includes an optical interface 414 that provides an optical connection between the source light guide 410 and the flow cell 416. In this manner, the light emissions 420 generated by the light source 408 can pass through the fluid in the flow cell 416.

[0163] The second optical interface 414 can provide an optical connection between the flow cell 416 and the detector light guide 422. The bubble sensing system 304 also includes a light detector 406 in optical communication with the detector light guide 422. In some embodiments, the light source 408, the light detector 406, and various other components can be disposed within the housing 402.

[0164] In some embodiments, light source 408 may be an LED or other light emitter. In some embodiments, light detector 406 may be a photodiode, a phototransistor, a photoresistor, a CMOS sensor, a charge coupled device, etc. Source light guide 410 may be an optical fiber, a light pipe, or other structure capable of transmitting an optical signal. Similarly, detector light guide 422 may be an optical fiber, a light pipe, or other structure capable of transmitting an optical signal.

[0165] In operation, the light source may be configured to emit light into a fluid sample (directly or indirectly), and the light detector may be configured to receive light that has passed through the sample (directly or indirectly). Figure 4In the example of , the light source and the light detector can be arranged to optically communicate with components on opposite sides of the circulation pool 416. The absorbance of air at certain wavelengths of light (including but not limited to ultraviolet wavelengths) is different from the absorbance of certain fluids (such as hydrocarbon fluids) (for example, hydrocarbon fluids absorb light at UV wavelengths, while air does not), allowing bubbles to be detected by evaluating the absorbance at ultraviolet wavelengths. However, other wavelengths of light can also be used to detect bubbles herein. For example, in some embodiments, a wavelength of light that is absorbed by CO2 (or another component in the air) to a different degree than that absorbed by the fluid containing the bubble can be used. Further, in addition to absorbance, other principles for detecting bubbles can also be applied. For example, the refractive index of air and certain fluids (such as fuel or hydrocarbon fluids) is different. This causes the light to bend at any curved interface, thereby producing an effect similar to the phenomenon of absorbance that can be detected using a light detector (for example, the light bends away from the light detector). In this case, many different wavelengths or bands of light can be used, such as light centered at 1550nm or other bands. Thus, the signal from the light detector will vary based on the amount of bubbles in the fluid, whether based on absorbance or other effects such as refraction, scattering, etc. The signal from the light detector can then be evaluated to determine the amount of bubbles in the fluid passing through the sensor channel.

[0166] Flow channel 302 includes channel diameter 418. Channel diameter 418 can have diameters of various sizes. In some embodiments, the diameter can be greater than or equal to 100 μm, 130 μm, 160 μm, 190 μm, 220 μm, or 250 μm. In some embodiments, the diameter can be less than or equal to 1000 μm, 850 μm, 700 μm, 550 μm, 400 μm, or 250 μm. In some embodiments, the diameter can fall within the range of 100 μm to 1000 μm, or 130 μm to 850 μm, or 160 μm to 700 μm, or 190 μm to 550 μm, or 220 μm to 400 μm.

[0167] Source light guide 410 may have a specific diameter 412. In some embodiments, diameter 412 may be greater than or equal to 100 μm, 200 μm, 250 μm, 300 μm, 350 μm, or 400 μm. In some embodiments, diameter 412 may be less than or equal to 800 μm, 700 μm, 600 μm, 500 μm, or 400 μm. In some embodiments, diameter 412 may fall within a range of 100 μm to 800 μm, or 150 μm to 500 μm, or 200 μm to 300 μm, or 250 μm to 350 μm, or may be approximately 300 μm.

[0168] The detector light guide 422 may have a specific diameter 424. In some embodiments, the diameter 424 of the detector light guide 422 is smaller than the diameter 412 of the source light guide 410. In some embodiments, the diameter 424 may be greater than or equal to 100 μm, 125 μm, 150 μm, 175 μm, or 200 μm. In some embodiments, the diameter 424 may be less than or equal to 400 μm, 350 μm, 300 μm, 250 μm, or 200 μm. In some embodiments, the diameter 424 may fall within a range of 100 μm to 400 μm, or 125 μm to 350 μm, or 150 μm to 300 μm, or 175 μm to 250 μm, or may be about 200 μm. The light guide 422 may include, for example, a light pipe, a fiber optic component, a liquid light guide, an orifice, etc.

[0169] Reference now Figure 5 , a schematic diagram of a portion of a bubble sensing system is shown according to various embodiments herein. A fluid moves through a flow path 502 defined by a flow cell 416. Light emissions 420 from a light source (not shown in this view) pass from a source light guide 410 to an optical interface 414, and then across the flow path 502, where the light emissions may encounter a bubble 506. The light emissions (as modified by their interaction with the bubble 506) then pass through another optical interface 414 before entering a detector light guide 422.

[0170] The light that passes through the detector light guide 422 can then be passed to a light detector (not shown in this view), which can generate a signal based on the received light. Figure 6 , shows a diagram of the potential versus time of a sensing system according to various embodiments herein. The changing potential is used as an example of a signal that can be generated based on the light received by the light detector. In this example, a baseline 602 is shown that indicates only a typical fluid in the flow path. However, Figure 6 Also shown is a negative deviation 604. This may indicate an air bubble in the flow path that is absorbing or scattering / refracting an amount of light or otherwise preventing an amount of light from entering the detector light guide 422. Thus, in various embodiments, the system and / or its sensor controller may be configured to identify air bubbles based on deviations of the signal received from the light detector from the baseline 602 level.

[0171] Notably, it has been discovered herein that large bubbles can actually cause the generated signal to exhibit a positive deviation from a baseline level, which then later drops below the baseline level (e.g., a sequence of positive deviation from the baseline followed by a negative deviation from the baseline). Thus, the size of the droplet can be detected by evaluating the received signal and specifically determining whether there is only a negative deviation or whether there is an initial positive deviation followed by a negative deviation.

[0172] Reference now Figure 7 , a schematic diagram of a portion of a bubble sensing system is shown according to various embodiments herein. As before, a fluid moves through a flow path 502 defined by a flow cell 416. Light emissions 420 from a light source (not shown in this view) pass from a source light guide 410 to an optical interface 414, and then across the flow path 502, where the light emissions may encounter a bubble 506. The light emissions (as modified by their interaction with the bubble 506) then pass through another optical interface 414 before entering a detector light guide 422.

[0173] However, this time, the positive deviation of the signal is ahead of the negative deviation of the signal. Now refer to Figure 8 , a diagram showing the relationship between potential and time of a sensing system is shown according to various embodiments herein. Figure 8 A baseline 602 value is shown initially being maintained and then a positive deviation 802 is shown followed by a negative deviation 604. This pattern indicates relatively large bubbles, as compared to bubbles that result in only negative deviations.

[0174] Further size information about the bubbles may also be gathered. For example, extremely large bubbles may result in a negative deviation (after an initial positive deviation) that keeps the sensor signal negative for a certain period of time longer than smaller drops.

[0175] Reference now Fig. 9 , a schematic diagram of a portion of a bubble sensing system is shown according to various embodiments herein. As before, a fluid moves through a flow path 502 defined by a flow cell 416. Light emissions 420 from a light source (not shown in this view) pass from a source light guide 410 to an optical interface 414, and then across the flow path 502, where the light emissions may encounter a bubble 506. The light emissions (as modified by their interaction with the bubble 506) then pass through another optical interface 414 before entering a detector light guide 422.

[0176] Fig.10 A diagram showing potential versus time for a sensing system according to various embodiments herein is shown. Fig.10 An initially maintained baseline 602 followed by a positive deviation 802 and an extended negative deviation 1002 is shown.

[0177] Reference now Fig.11, a schematic diagram of components of the system of the present invention is shown according to various embodiments of the present invention. The system may include a fluid filter system 1108. The fluid filter system 1108 may include a filter head 1102 and a filter unit 1104. The fluid filter system 1108 may be used to filter fuel, hydraulic fluid, lubricant, coolant, etc. The fluid filter system 1108 may be specifically used to filter various liquids. In some embodiments, the fluid filter system 1108 may be located on a vehicle, but in some embodiments may be located on a non-vehicle device.

[0178] Fig.11 Also shown is the housing 402 of the bubble sensing system 304. The housing 402 may be connected to the fluid filter system 1108 via a control cable 1106, which may include electrical wires and / or optical fibers therein. Fig.11 The housing 402 is depicted separately from the fluid filter system 1108, but it should be understood that in various embodiments herein, the housing 402 or other components of the bubble sensing system 304 may be physically integrated into and / or mounted on the fluid filter system 1108. Further, in some embodiments, the bubble sensing system 304 does not interface with the fluid filter system 1108, but rather interfaces with a fluid line or a component connected to the fluid line at a different point in the fluid system.

[0179] The bubble sensing system 304 may include one or more components or sensor devices and / or may be configured to receive data from one or more components or sensor devices. By way of example, the bubble sensing system 304 may interface with a vehicle data network 308. In some embodiments, the vehicle data network 308 may be a CANBus network. However, the vehicle data network 308 may also be (or be connected to) other types of data networks. The vehicle data network may be interfaced via a wired or wireless protocol.

[0180] In some embodiments, the bubble sensing system 304 may communicate with the first additional data generating or receiving device 1112 and / or the second additional data generating or receiving device 1114. The data may include, but is not limited to, fluid age, fluid temperature, fluid viscosity, one or more geolocation and / or altitude data, weather data, temperature data, pressure data, humidity data, fluid filter model, engine model, driver ID, and detected maintenance, refill, and / or refueling times.

[0181] In some, the bubble sensing system 304 may also include other types of contaminant sensors. For example, the first or second additional data generation and / or receiving device may include another type of fluid contaminant sensor or may communicate with another type of fluid contaminant sensor. In various embodiments herein, the system may then associate the maintenance, refilling or fuel replenishment location with subsequent changes in the contaminant level identified (at least in part) by the contaminant sensor to identify the impact of the specific location on the contaminant level, and therefore the impact on the fluid contaminant content. Such contaminant sensors may include but are not limited to on-board particle counters / monitors. In some embodiments, the contaminant sensor may include an optical-based sensor that utilizes the detection of light blocking to perform particle detection. For example, particles may pass through an optical flow cell including a light emitter. These particles may block part of the light, thereby forming a shadow. These shadows may be detected by a light detector. In addition to optical systems based on light, contaminant sensors may also rely on other detection methods. For example, contaminant sensors may also rely on electrical, magnetic, weight and / or density properties to detect contaminants. In some embodiments, the contaminant sensor herein may detect particles according to ISO 11171 on particle counting data in a fluid. It should be understood that data from other types of pollutant sensors (and in particular data from particle counters / monitors) may be used alone or in combination with other types of pollutant data or constraint data discussed herein.

[0182] Reference now Fig.12 , a schematic diagram of a system is shown according to various embodiments herein. Fig.12 Vehicle 1202 is shown at service location 1212. Vehicle 1202 includes fluid system 1204 (which may be a fuel system, hydraulic fluid system, lubricant system, coolant system, etc.) that includes bubble sensing system 304.

[0183] In some cases, bubble sensing system 304 may be in direct wireless data communication with cloud 122 or another data network. In some cases, bubble sensing system 304 may be in indirect wireless data communication with cloud 122 or another data network. In some embodiments, bubble sensing system 304 may communicate with cellular tower 1220, which in turn may relay data communications to and from cloud 1214 and its components such as server 1216 (real or virtual) and database 1218 (real or virtual).

[0184] Various protocols may be used for wireless communication. For example, wireless communications / signals exchanged between the bubble sensing system 304 and / or the bubble sensing system and the cloud 1214 (or between the bubble sensing system 304 and / or components of the bubble sensing system) may follow many different communication protocol standards and may be conducted via radio frequency transmission, inductively, magnetically, optically, or in some embodiments even via wired connections. In some embodiments herein, IEEE 802.11 (e.g., ), (e.g., BLE, 4.2 or 5.0), Or cellular transmission protocols / platforms, such as CDMA, cdmaOne, CDMA2000, TDMA, GSM, IS-95, LTE, 5G, GPRS, EV-DO, EDGE, UMTS, HSDPA, HSUPA, HSPA+, TD-SCDMA, WiMAX, Micro.Sp, etc. In various embodiments, different standard or proprietary wireless communication protocols may also be used.

[0185] As mentioned, the cloud 1214 resources may include a database 1218. Such a database 1218 may store various information, including, but not limited to, fluid service location data (e.g., service location ID, service location geolocation and / or altitude data, service location visit data, service location filter load impact data, etc.), refueling location data (e.g., refueling location ID, refueling location geolocation and / or altitude data, fuel filter load rate data associated with a specific refueling location, refueling location estimated impurity / contamination information, refueling location visit data, refueling location filter load impact data, etc.), fleet data, vehicle data, filtration system data, etc.

[0186] It should be understood that the database contents may be distributed across many different physical systems, devices, and locations. Fig.12 1218, but it is understood that database records may also be stored at the level of the bubble sensing system 304. In various embodiments, the database 1218 or portions thereof may be stored at a location remote from other components of the system, such as the bubble sensing system 304. In some embodiments, records or portions of the database may be stored across different physical locations, and in some embodiments, may be cached across different physical locations for ease of access.

[0187] In some embodiments, the service location 1212 may include a location communication device 1208. The location communication device 1208 may include various components. In some embodiments, the location communication device 1208 may be a wireless data gateway, including components such as a router and / or other data networking hardware. In some cases, the bubble sensing system 304 may communicate wirelessly with the location communication device 1208 to provide communication with the cloud 1214 or another data network. In some cases, the bubble sensing system 304 may receive information from the location communication device 1208, such as geolocation and / or altitude data (which may include latitude / longitude coordinates, etc.), or other location identification information, such as the nearest address, the nearest landmark, etc. As used herein, unless the context indicates otherwise, the term "geolocation data" shall include references to all location identification data.

[0188] In some cases, geolocation data may be obtained from a geolocation system based on satellite 1222. Such systems may include, but are not limited to, GPS L1 / L2, GLONASS G1 / G2, BeiDou B1 / B2, Galileo E1 / E5b, SBAS, etc. In various embodiments, the system may include geolocation circuitry (as described below), which may include an appropriate signal receiver or transceiver for interfacing with satellite 1222, and / or the geolocation circuitry may interface with and / or receive data from a separate device or system that provides geolocation data or obtains geolocation data from satellite 1222 or other devices. However, it should be understood that geolocation data herein is not limited to data that may be received or obtained from an interface with satellite 1222. Geolocation data may also be obtained from addresses, beacons, landmarks, various reference technologies, IP address evaluations, etc. Altitude may be measured directly using an altimeter or similar sensor, or may be inferred based on geolocation data, provided that the vehicle or other device for which the measurement bubble is targeted is at ground level.

[0189] In various embodiments, the bubble sensing system 304 may also include and / or communicate with a mobile communication / guidance device 1210. In some cases, the mobile communication / guidance device 1210 may be used to provide data communication for the bubble sensing system 304 and the cloud or another data network. In various embodiments, the mobile communication / guidance device 1210 may provide output to the vehicle 1202 or the driver of the vehicle 1202 or provide input from the vehicle or the driver of the vehicle. In some cases, the mobile communication device may be used to provide recommendations (visual, auditory, and / or tactile recommendations) to the driver of the vehicle. For example, in various embodiments, the system may generate recommendations, and the recommendations may be forwarded to the mobile communication / guidance device 1210 associated with the vehicle 1202 or the driver of the vehicle 1202. In various embodiments herein, the system may be configured to generate recommendations for the driver of the vehicle 1202 based on the detected bubbles. In various embodiments, these recommendations include at least one of a recommended service location, a recommended filter type, a recommended service time, and a recommended vehicle service.

[0190] Specific recommendations / reports generated by the system may include specific information points. However, as just one example, the bubble sensing system 304 and / or its components may be configured to generate reports related to different service locations (and / or their patterns). As another specific example, the bubble sensing system 304 and / or its components may be configured to generate a report describing the frequency with which different drivers in the fleet use recommended and non-recommended services.

[0191] In some embodiments, the mobile communication / guidance device 1210 may be, for example, a smart phone or another type of computing device with wireless communication capabilities. In some embodiments, the mobile communication / guidance device 1210 may be a vehicle navigation system.

[0192] In some embodiments, the bubble sensing system 304 may also include and / or communicate with a fleet monitoring center 1224 (real or virtual). The fleet monitoring center 1224 may include a remote computing device 1226 and may receive information and / or recommendations about specific vehicles and / or specific service locations. In some cases, the bubble sensing system 304 may be used to provide recommendations to and / or receive information or instructions from a fleet control operator at the fleet monitoring center 1224.

[0193] In various embodiments, the systems described herein may also be used as or as a service guidance system for the vehicle 1202. For example, the bubble sensing system 304 and / or components thereof may be configured to query the database 1218, which may include records of specific service locations. The bubble sensing system 304 may be configured to provide at least one of a route recommendation and a service location recommendation to a user output device.

[0194] Reference now Fig.13 , a block diagram of components of the bubble sensing system 304 is shown according to various embodiments herein. However, it should be understood that various embodiments may include a greater or lesser number of components, and this schematic diagram is illustrative only. The bubble sensing system 304 includes a housing 402 and a sensor controller 1304 or ("control circuit" or "system control circuit"). The sensor controller 1304 may include various electronic components, including but not limited to a microprocessor, a microcontroller, an FPGA (field programmable gate array) chip, an application specific integrated circuit (ASIC), etc. The sensor controller 1304 may perform various operations as described herein. However, it should be understood that the various operations herein may be performed across multiple devices having separate physical circuits, processors, or controllers, wherein different operations are redundantly performed or divided across different physical devices. As such, some operations may be performed (in whole or in part) at the edge, such as by a circuit / processor / controller associated with the bubble sensing system 304, while other operations may be performed (in whole or in part) by a separate device or in the cloud.

[0195] The bubble sensing system 304 can include a light source 408 and a light detector 406. Both the light source 408 and the light detector 406 can be associated with a flow cell 416. The light source 408 can communicate with a light source controller 1306. The light detector 406 can communicate with a light detector channel interface 1310.

[0196] In various embodiments, the bubble sensing system 304 may include and / or communicate with a flow sensor 306 and a flow sensor channel interface 1314. In various embodiments, the bubble sensing system 304 may include and / or communicate with another type of sensor such as a temperature sensor 1320 and a temperature sensor channel interface 1318. Other types of sensors herein may include vibration sensors, flow sensors, pressure sensors, etc.

[0197] The channel interface may include various components, such as amplifiers, analog-to-digital converters (ADCs), digital-to-analog converters (DACs), digital signal processors (DSPs), filters (high pass, low pass, band pass), etc. In some cases, the channel interface may not exist as a discrete component, but may be integrated into the sensor controller 1304.

[0198] The temperature sensor herein can be of various types. In some embodiments, the temperature sensor 1320 can be a thermistor, a resistance temperature device (RTD), a thermocouple, a semiconductor temperature sensor, and the like.

[0199] In some embodiments, one or more temperature sensors of the present invention may be configured to measure the temperature of the light source and / or light detector of the present invention. In this way, the signal of the light detector can be corrected for temperature effects (e.g., the signal can be normalized). This can be performed in various ways. In one method, an empirically obtained (or otherwise obtained) standard curve or calibration curve that relates the light output of the light source and / or the voltage output of the light detector to temperature can be applied to normalize the signal of the light detector. In some methods, an equation that relates the light detector voltage output to temperature within a certain operating temperature range can be used to correct the signal of the light detector for temperature or normalize it.

[0200] In some embodiments, one or more pressure sensors may also be included herein. The pressure sensor herein may be of various types. The pressure sensor may include, but is not limited to, a strain gauge pressure sensor, a capacitive pressure sensor, a piezoelectric pressure sensor, etc. In some embodiments, the pressure sensor herein may be a MEMS-based pressure sensor. In various embodiments, the pressure sensor may be a high-speed (e.g., high sampling rate) pressure sensor. In various embodiments, the high-speed pressure sensor may be sampled at a rate of 1,000 Hz, 1,500 Hz, 2,000 Hz, 2,500 Hz, 3,000 Hz, 5,000 Hz, 10,000 Hz, 15,000 Hz, 20,000 Hz or higher or at a rate falling within the range between any of the foregoing. In various embodiments, the high-speed pressure sensor may have a response time of less than 10 milliseconds, 5 milliseconds, 2.5 milliseconds, 1 millisecond, 0.5 milliseconds, 0.25 milliseconds, 0.1 milliseconds, 0.05 milliseconds, or 0.01 milliseconds, or a response time falling within the range between any of the foregoing.

[0201] The processing power of the sensor controller 1304 and its components may be sufficient to perform various operations, including various operations on signals / data from sensors or other components, including but not limited to: averaging, averaging over time, statistical analysis, normalization, aggregation, classification, deletion, traversal, transformation, squeezing (such as eliminating selected data and / or converting data into a smaller granular form), compression (such as using a compression algorithm), merging, insertion, time stamping, filtering, discarding outliers, discarding values ​​exceeding a threshold, calculating trends and trend lines (linear, logarithmic, polynomial, power, exponential, moving average, etc.), normalizing data / signals, performing peak detection and / or peak fitting algorithms, etc. Fourier analysis can decompose a physical signal into multiple discrete frequencies or a spectrum within a continuous range. In various embodiments herein, operations on signals / data may include a fast Fourier transform (FFT) for converting data / signals from the time domain to the frequency domain. Other operations on signals / data here may include spectral estimation, frequency domain analysis, root mean square acceleration values ​​(G RMS ), calculation of acceleration spectral density, power spectral density, Fourier series, Z transform, resonant frequency determination, harmonic frequency determination, etc. It should be understood that although the various operations described herein (such as fast Fourier transform) can be performed by a general-purpose microprocessor, they can also be performed more efficiently by a digital signal processor (DSP), which in some embodiments can be integrated with the sensor controller 1304 or can exist as a separate discrete component.

[0202] In various embodiments, the bubble sensing system 304 may include a power circuit 1322. In some embodiments, the power circuit 1322 may include various components including, but not limited to, a battery 1324, a capacitor, a power receiver such as a wireless power receiver, a transformer, a rectifier, etc. In some embodiments, the bubble sensing system 304 may be configured to operate on engine power or another power source associated with a device with which the bubble sensing system 304 is used or installed.

[0203] In various embodiments, the bubble sensing system 304 may include an output device 1326. The output device 1326 may include various components for visual and / or audio output, including, but not limited to, lights (such as LED lights), display screens, speakers, etc. In some embodiments, the output device may be used to provide notifications or alerts to system users, such as the current system status, problem indications, required user intervention, appropriate time to perform maintenance actions, etc.

[0204] In various embodiments, the bubble sensing system 304 may include a memory 1328 and / or a memory controller. The memory may include various types of memory components, including dynamic RAM (D-RAM), read-only memory (ROM), static RAM (S-RAM), disk storage, flash memory, EEPROM, battery-powered RAM (such as S-RAM or D-RAM), and any other type of digital data storage component. In some embodiments, the electronic circuit or electronic component includes volatile memory. In some embodiments, the electronic circuit or electronic component includes non-volatile memory. In some embodiments, the electronic circuit or electronic component may include transistors that are interconnected to operate as latches or triggers to provide positive feedback, so that the circuit has two or more metastable states and remains in one of these states until changed by an external input. Data storage may be based on such a circuit containing a trigger. Data storage may also be based on charge storage in a capacitor or based on other principles. In some embodiments, the non-volatile memory 1328 may be integrated with the sensor controller 1304.

[0205] In various embodiments, the bubble sensing system 304 may include a clock circuit 1330. In some embodiments, the clock circuit 1330 may be integrated with the sensor controller 1304. Fig.13 However, it should be understood that various embodiments herein may include a data / communication bus to provide, for example, 2 C. Data transmission between components such as a serial peripheral interface (SPI), a universal asynchronous receiver / transmitter (UART), etc. In some embodiments, an analog signal interface may be included. In some embodiments, a digital signal interface may be included.

[0206] In various embodiments, the bubble sensing system 304 may include a communication circuit 1332. In various embodiments, the communication circuit may include components such as an antenna 1334, an amplifier, a filter, a digital-to-analog converter, and / or an analog-to-digital converter. In some embodiments, the bubble sensing system 304 may also include a wired input / output interface 1336 for wired communication with other systems / components, including but not limited to one or more vehicle ECUs, a CANBus network, etc.

[0207] The bubble monitoring system herein may also include a geolocation and / or altitude circuit 1340. In various embodiments, the geolocation and / or altitude circuit 1340 may be configured to generate or receive geolocation and / or altitude data. In various embodiments, the geolocation and / or altitude circuit 1340 may receive geolocation and / or altitude data from a separate device. In various embodiments, the geolocation and / or altitude circuit 1340 may infer geolocation based on detection of wireless signals (such as WIFI signals, cellular tower signals, etc.). In various embodiments, the geolocation and / or altitude circuit 1340 may include satellite communication circuitry. In various embodiments, the geolocation and / or altitude circuit 1340 may include or communicate with an altimeter or similar sensor.

[0208] The system and / or sensor controller 1304 can be configured to perform various calculations as described herein. For example, in various embodiments, using inputs as described herein, the sensor controller 1304 can be configured to estimate the amount of bubbles. It should be understood that references to bubbles herein should refer to free air unless the context indicates otherwise. Many other calculations that can be performed by the sensor controller 1304 and / or other components of the system will be described in more detail below. Estimating the amount of air in a fluid

[0209] As described herein, the system can be configured to estimate the amount of air in the fluid. This estimation can be based on various inputs or estimates, including one or more of the following: the number of bubbles detected per unit time (N), the average size / volume of the bubbles detected (V), the fluid flow rate through the sensor (F), a sampling factor (S) (if there is no sampling bias, the factor is equal to 1), etc. In one approach, the amount of air (as bubbles) in the fluid can be estimated according to the following equation and described as the fraction of air in the fluid:

[0210] The number of bubbles detected per unit time may be detected directly by the sensor(s) of the fluid water content sensing system herein, as described and illustrated with respect to the examples below.

[0211] Can be based on Figures 5 to 10 The optical signal described is used to estimate the size / volume of the detected bubble, as described above.

[0212] The flow rate of the fluid can be measured / determined / estimated in various ways. In some embodiments, the system can include a flow sensor that generates a value of the fluid flow rate. In some embodiments, the system can receive data about the fluid flow rate from a vehicle data network such as a CANBus.

[0213] In some embodiments, the value of the flow rate can be estimated using the pipe flow equation and information about the pressure drop between two points. Specifically, there is a certain relationship between the flow rate and the pressure drop that can be used to estimate the flow rate. Therefore, in some embodiments, the pressure measurements upstream and downstream of the location where the bubble is detected can be used to estimate the fluid flow rate. In some embodiments, the relationship between the pressure drop and the flow rate can be determined empirically and then programmed into the system or its components.

[0214] In some embodiments, the relationship between pressure drop and flow rate through a flow cell or fluid line herein can be determined empirically for water and then modified for another fluid type. By way of example, the following equation can be used, where the values ​​P1 and P2 are determined empirically for water, and where P S,F is the pressure drop across the sensor when the fluid is another fluid, μ W and μ F are the dynamic viscosities of water (1 cP) and another fluid (for example, ~2.5 cP in the case of hydrocarbon fuel only), and U S,W is the fluid flow through the sensor:

[0215] In some embodiments, there may be a relationship between the total number of bubbles detected per unit time (normalized by the fluid flow rate) and the amount of bubbles in the fluid. Thus, in some embodiments, data about the number of bubbles detected by the sensor(s) of the bubble sensing system herein may be combined with data about the fluid flow rate to generate an estimate of the amount of bubbles in the fluid. In some embodiments, the fluid flow rate may be estimated by analyzing the bubble size distribution and peak width.

[0216] It will be appreciated that whether the level of bubbles is short-term (acute) or long-term (chronic) may have significant implications. This significance may be applied to determine the likely source of aeration in the fluid and the relative risk of damage to the vehicle. For example, if high aeration levels in the fluid are present for only a very short period of time, then this may be due to a recent leak, etc. Conversely, if high levels of bubbles are detected over a long period of time, this may point to another cause.

[0217] The pattern (temporal, geographic, etc.) of the amount of bubbles detected in the fluid may also be of significance.

[0218] In various embodiments herein, a machine learning algorithm may be used to derive patterns between the estimated amount of bubbles in the fluid and multiple other pieces of information available to the system, including but not limited to the geolocation and / or altitude of the service location, the time of the event, ambient temperature, ambient humidity, weather conditions, vehicle operator identity, travel route, etc.

[0219] The machine learning algorithms used herein may include, but are not limited to, supervised learning algorithms and unsupervised learning algorithms. The machine learning algorithms used herein may include, but are not limited to, classification algorithms (supervised algorithms for predicting classification labels), clustering algorithms (unsupervised algorithms for predicting classification labels), integrated learning algorithms (supervised meta-algorithms for combining multiple learning algorithms), general algorithms for predicting arbitrary structured sets of labels, multilinear subspace learning algorithms (using tensor representations to predict labels of multidimensional data), real-valued sequence labeling algorithms (predicting sequences of real-valued labels), regression algorithms (predicting real-valued labels), and sequence labeling algorithms (predicting sequences of classification labels).

[0220] The machine learning algorithms herein may also include parameter algorithms (such as linear discriminant analysis, quadratic discriminant analysis, and maximum entropy classifiers) and non-parametric algorithms (such as decision trees, kernel estimation, naive Bayes classifiers, neural networks, perceptrons, and support vector machines). The clustering algorithms herein may include classification mixture models, deep learning methods, hierarchical clustering, K-means clustering, correlation clustering, and kernel principal component analysis. The ensemble learning algorithms herein may include boosting, bootstrap aggregation, ensemble averaging, and hybrid experts. The general algorithms herein for predicting arbitrary structured sets of labels may include Bayesian networks and Markov random fields. The multilinear subspace learning algorithms herein may include multilinear principal component analysis (MPCA). Real-valued sequence labeling algorithms may include Kalman filters and particle filters. The regression algorithms herein may include both supervised (such as Gaussian process regression, linear regression, neural networks, and deep learning methods) and unsupervised (such as independent component analysis and principal component analysis) methods. The sequence labeling algorithms in this paper can include both supervised (such as conditional random fields, hidden Markov models, maximum entropy Markov models, and recurrent neural networks) and unsupervised (hidden Markov models and dynamic time warping) methods.

[0221] In some embodiments, various actions / operations of the system may be triggered by the estimated amount of bubbles exceeding a threshold. In some embodiments, these thresholds may be predetermined and / or fixed. In other embodiments, these thresholds may be dynamic.

[0222] In some embodiments, the system can distinguish between an estimated amount of bubbles in the fluid that requires immediate cessation of vehicle operation and an estimated amount of bubbles in the fluid that allows continued operation. In one example, distinguishing between these different categories can be performed based on thresholds. The different categories of estimated bubble amounts can also be reflected in qualitative notifications sent to the vehicle operator, fleet controller, or another person or system. For example, in some embodiments, a notification can be sent that can reflect whether the estimated amount of bubbles in the fluid is "high," "medium," or "low."

[0223] In some embodiments, the threshold value may be different depending on whether the estimated amount of air or bubbles is only short-term (acute or temporary) or long-term (chronic). In various embodiments, the threshold value for short-term values ​​may be higher than the threshold value for long-term values. Reduce the impact of water droplets

[0224] In some instances, water droplets may be present in the fluid lines of the system. It has been discovered herein that because water has a different refractive index than other vehicle or system fluids, light may be scattered and reflected off the interface (the interface between the system fluid and the water droplets), or otherwise transmitted and refracted across the interface. This results in less light reaching the sensor detector, and the appearance of light absorption events. As a result, water droplets can also create what appear to be absorption peaks, and therefore can potentially be confused with bubbles, making the presence of water droplets a potential source of error when measuring bubbles in fluid lines.

[0225] However, various embodiments herein can be configured to prevent the presence of water droplets from interfering with the measurement of bubbles in the fluid. In some embodiments, signal processing methods can be used to distinguish water droplets from bubbles. Specifically, it has been found that bubbles generate absorption peaks that appear to have larger absorption magnitudes and peak widths. Thus, according to the system herein, signal processing techniques can be used to prevent the presence of water droplets from interfering with the measurement of bubbles in the fluid. For example, in some embodiments, the system can be configured to exclude peaks that exceed a threshold value of absorbance magnitude and / or peak width when calculating the amount of bubbles in the fluid. The threshold value can be an absolute value or a relative value. In some embodiments, the threshold value can be a statistical measurement such as a mean value, a standard deviation value of a distribution, a percentage value, etc.

[0226] Other techniques may also be used to mitigate the effect of water droplets on the measurement of bubbles in the fluid. In some embodiments, a secondary detector may be used to determine the amount of reflected light that distinguishes water droplets from bubbles. For example, in some embodiments, the system may be configured to measure the absorbance of two different wavelengths of light (e.g., using a first light source configured to emit near infrared light and a second light source configured to emit light in the visible spectrum) and distinguish water droplets from bubbles by comparing an absorption peak generated at one wavelength to an absorption peak generated at another wavelength.

[0227] In some embodiments, a secondary detector can be used to determine the amount of reflected light that distinguishes water droplets from bubbles. Fig.14 , a schematic diagram of a portion of a bubble sensing system is shown according to various embodiments herein. Fig.14 Generally the same as described above Figure 5 However, in this embodiment, a secondary detector 1402 is included and positioned to detect light reflected from bubbles passing through the sensor. method

[0228] Many different methods are contemplated herein, including but not limited to methods of detecting bubbles, methods of monitoring fluid ventilation, methods of detecting pressure, methods of monitoring vehicle operation, etc. Aspects of system / device operation described elsewhere herein may be performed as operations of one or more methods according to various embodiments herein.

[0229] In an embodiment, a method of determining a restriction of a filter is included, which may include evaluating a signal received from a light detector, detecting bubbles based on the signal received from the light detector, and generating an estimate of the restriction of a liquid filter upstream of the light detector based on the detected bubbles.

[0230] In an embodiment of the method, a light detector is disposed at an area under vacuum pressure within a fluid system (fuel system, hydraulic fluid system, lubricant system, etc.). In an embodiment of the method, the light detector is disposed within the fluid system downstream of a filter and upstream of a fluid pump, although other locations of the light detector relative to the filter(s) and pump(s) are contemplated herein.

[0231] In an embodiment, the method may further include distinguishing bubbles from water drops in the fluid based on at least one of the peak magnitude and the peak width. In an embodiment, the method may further include distinguishing bubbles from water drops based on the ratio of the peak magnitude to the peak width. In an embodiment, the method may further include distinguishing bubbles from water drops based on the peak magnitude. In an embodiment, the method may further include distinguishing bubbles from water drops based on the magnitude of the reflection peak preceding the absorption peak.

[0232] In an embodiment, the method may further comprise emitting light into the sampling channel. In an embodiment of the method, emitting light into the sampling channel further comprises emitting near infrared light.

[0233] In an embodiment, the method may further include generating an estimate of restriction of a fluid filter upstream of the light detector based on one or more characteristics of the detected air bubbles. In an embodiment of the method, generating an estimate of restriction of a fluid filter upstream of the light detector based on one or more characteristics of the detected air bubbles further includes generating the estimate of restriction using fluid flow through the filter.

[0234] In an embodiment, the method may further include determining an end of life of the fluid filter based on an estimated degree of restriction of the fluid filter.

[0235] In an embodiment, the method may further include generating an alarm when the number of bubbles detected exceeds a threshold value above the baseline value.

[0236] In an embodiment, the method may further comprise tracking the number of bubbles detected over time.

[0237] In an embodiment, a method of estimating an amount of air in a hydraulic fluid line is included, the method comprising detecting air bubbles based on a signal received from a light detector; and estimating the amount of air in the hydraulic fluid line based on the detected air bubbles.

[0238] In an embodiment, the method may further include generating an alarm when the number of bubbles detected exceeds a threshold. In an embodiment, the method may further include generating an alarm when the total volume of bubbles exceeds a threshold. In an embodiment, the method may further include tracking the number of bubbles detected over time.

[0239]

[0011] In an embodiment, a method of estimating an amount of pressure in a fluid line is included, the method comprising detecting bubbles based on a signal received from a light detector; and estimating the amount of pressure in the fluid line based on the detected bubbles.

[0240] Aspects may be better understood with reference to the following examples. These examples are intended to represent specific embodiments, but are not intended to limit the overall scope of the embodiments herein. Examples Example 1: Detecting bubbles in fuel

[0241] The bubble sensing system is configured to Figure 3 The same as shown in . Specifically, the sensing system was prepared using a 300um ID borosilicate glass flow cell. The light source was a near-infrared LED (1550nm; Raytheon Labs) and was focused on the channel using a 200um fiber optic cable (Raytheon Labs). The light was detected using a variable gain InGaAs detector (Raytheon Labs) set to 60dB gain. The light was collected and delivered to the detector using a 400um fiber optic cable. The flow cell was encased in a machined aluminum body and was designed to sample a portion of the mainstream.

[0242] The bubble sensing system is placed on a test bench to simulate the performance of a fuel filter under suction. The test bench consists of a filter housing (which can contain a filter or be an empty housing), a valve for adding an artificial restriction upstream of the filter housing, and a pump located downstream of the filter housing and the valve. The sensor is placed between the filter housing and the pump. Vacuum pressure causes air to be generated in the fuel sample. The filter acts as a restriction and nucleation point and can change the size and amount of air in the fuel. A dP sensor is placed on the valve / filter housing assembly to monitor the effective filter restriction. The test bench is operated at different flow rates and valve restrictions. The signal from the photodetector is recorded. Signal processing and peak identification are completed in MATLAB using standard peak fitting algorithms.

[0243] Fig.15 The signal is shown for a flow rate of 4 lpm, with a clean filter (Donaldson P591392) and no additional restriction in the valve (valve / filter assembly dP = 0.71 PSI). The large peaks observed are bubbles; the small peaks are electronic noise, which is also present in the no-flow control experiment. This shows that the system herein can be used to obtain bubble counts over time. Example 2: Difference in Bubble Counts with Restriction and / or No Filter

[0244] The bubble sensing system is configured to Figure 3 The same as shown in . Specifically, the sensing system was prepared using a 300um ID borosilicate glass flow cell. The light source was a near-infrared LED (1550nm; Raytheon Labs) and was focused on the channel using a 200um fiber optic cable (Raytheon Labs). The light was detected using a variable gain InGaAs detector (Raytheon Labs) set to 60dB gain. The light was collected and delivered to the detector using a 400um fiber optic cable. The flow cell was encased in a machined aluminum body and was designed to sample a portion of the mainstream.

[0245] The bubble sensing system is placed on a test bench to simulate the performance of a fuel filter under suction. The test bench consists of a filter housing (which can contain a filter or be an empty housing), a valve for adding an artificial restriction upstream of the filter housing, and a pump located downstream of the filter housing and the valve. The sensor is placed between the filter housing and the pump. Vacuum pressure causes air to be generated in the fuel sample. The filter acts as a restriction and nucleation point and can change the size and amount of air in the fuel. A dP sensor is placed on the valve / filter housing assembly to monitor the effective filter restriction. The test bench is operated at different flow rates and valve restrictions. The signal from the photodetector is recorded. Signal processing and peak identification are completed in MATLAB using standard peak fitting algorithms. *Noise peaks in the no-flow control group have been subtracted.

[0246] These data indicate that adding restriction to the filter under aspiration increases the number of bubbles detected. These data further indicate that not having a filter results in an increased number of peaks. These bubbles are generally smaller and can be used to determine if a filter is not installed. Example 5: Distinguishing bubbles from water drops

[0247] The bubble sensing system is configured to Figure 3The sensor is placed on a fuel-water separation test bench commonly used for testing water removal filters according to standard methods. In one example, the system is configured so that water droplets (d50 = 75 μm, 500 ppm) will be received by the sensor. In another case, the sensor is placed on the fuel test bench described in Example 1, wherein the system is configured so that the sensor can receive bubbles. The mainstream operates at 3L / min and consists of internal combustion engine fuel. Signal data is captured using a data acquisition system. Signal processing and peak identification are completed in MATLAB using a standard peak fitting algorithm.

[0248] exist Fig.16 , a histogram of peak counts at different absorbance levels for 15 minutes of data through the test system is shown. It can be seen that the distribution of air peaks produces larger absorbance values ​​than water droplets. Similarly, Ref. Fig.17 , shows a graph of 30 seconds of data, which shows the relationship between absorbance and peak width. It can be seen that bubbles generate peak widths that are much larger on average than water droplets. This example shows that bubbles generate absorption peaks that are significantly different from water droplets. In this way, the system herein can be configured to distinguish water droplets from bubbles and exclude the influence of bubbles when measuring the water concentration in the fluid. Or exclude the influence of water droplet concentration when measuring the bubble concentration in the fluid.

[0249] It should be noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. It should also be noted that the term "or" is generally used in its sense including "and / or" unless the context clearly dictates otherwise.

[0250] It should also be noted that, as used in this specification and the appended claims, the phrase "configured to" describes a system, device, or other structure that is constructed or configured to perform a particular task or adopt a particular configuration. The phrase "configured to" may be used interchangeably with other similar phrases, such as arranged and configured, constructed and arranged, constructed to, manufactured and arranged to, etc.

[0251] All publications and patent applications in this specification are indicative of the level of ordinary technicians in the field to which the invention belongs. All publications and patent applications are incorporated herein by reference to the same extent as if each individual publication or patent application was specifically and individually indicated by reference.

[0252] As used herein, the recitations of numerical ranges by endpoints shall include all numbers subsumed within that range (eg, 2 to 8 includes 2.1, 2.8, 5.3, 7, etc.).

[0253] The headings used herein are provided to be consistent with the recommendations under 37 CFR 1.77, or to otherwise provide organizational clues. These headings should not be considered to limit or characterize the inventions set forth in any claims that may be published from this disclosure. As an example, although the heading refers to "Technical Field", such claims should not be limited by the language selected under this heading to describe the so-called technical field. In addition, the description of the technology in the "Background Art" does not admit that the technology is prior art to any invention in the disclosure. "Summary of the Invention" should also not be considered to characterize the inventions set forth in the published claims.

[0254] The embodiments described herein are not intended to be exhaustive or to limit the invention to the exact forms disclosed in the subsequent specific embodiments. On the contrary, the embodiments are selected and described so that other persons skilled in the art can understand and appreciate the principles and practices. Thus, various aspects have been described with reference to various specific and preferred embodiments and techniques. However, it should be understood that many changes and modifications can be made while remaining within the spirit and scope of this article.

Claims

1. A fluid system ventilation detector, comprising: An optical bubble sensor, the optical bubble sensor comprising light source; Light detector; as well as Sensor controller; wherein the sensor controller communicates signals with the light detector; Wherein, the sensor controller is configured as detecting bubbles based on a signal received from the light detector; and The ventilation of the fluid is estimated based on the detected bubbles.

2. A fluid system ventilation detector as claimed in any one of claims 1 and 3 to 11, wherein: The sensor controller is configured to distinguish between bubbles and water droplets in the fluid based on at least one of a peak magnitude and a peak width.

3. A fluid system ventilation detector as claimed in any one of claims 1 to 2 and 4 to 11, wherein: The sensor controller is configured to distinguish between air bubbles and water drops based on a ratio of peak magnitude to peak width.

4. A fluid system ventilation detector as claimed in any one of claims 1 to 3 and 5 to 11, wherein: The sensor controller is configured to distinguish between air bubbles and water drops based on the peak magnitude.

5. A fluid system ventilation detector as claimed in any one of claims 1 to 4 and 6 to 11, wherein: The sensor controller is configured to distinguish between air bubbles and water droplets based on a magnitude of a reflection peak preceding a peak resulting from absorbance, refraction, and / or scattering.

6. A fluid system ventilation detector as claimed in any one of claims 1 to 5 and 7 to 11, wherein: The fluid system ventilation detector is an on-board sensing system.

7. A fluid system ventilation detector as claimed in any one of claims 1 to 6 and 8 to 11, wherein: The optical bubble sensor is configured to be disposed downstream of the filter and upstream of the fluid pump.

8. A fluid system ventilation detector as claimed in any one of claims 1 to 7 and 9 to 11, wherein: The optical bubble sensor is configured to be disposed at a region within the fluid system that is under vacuum pressure.

9. A fluid system ventilation detector as claimed in any one of claims 1 to 8 and 10 to 11, wherein: The fluid system aeration detector is configured to generate an alarm when a detected bubble count exceeds a threshold value within a certain period of time.

10. A fluid system ventilation detector as claimed in any one of claims 1 to 9 and 11, wherein: The fluid system ventilation detector is configured to generate an alarm when a detected bubble volume exceeds a threshold value.

11. The fluid system ventilation detector according to any one of claims 1 to 10, wherein: The fluid system aeration detector is configured to track the count, size distribution and / or volume of detected bubbles over time.

12. A method for detecting ventilation of a fluid system, comprising: detecting bubbles based on a signal received from a light detector; estimating ventilation of the fluid based on the detected bubbles; as well as Air bubbles and water droplets in the fluid are distinguished based on at least one of peak magnitude and peak width.

13. The method of any one of claims 12 and 14, further comprising distinguishing between air bubbles and water droplets based on a ratio of peak magnitude to peak width.

14. The method of any one of claims 12 to 13, further comprising distinguishing between air bubbles and water droplets based on the magnitude of a reflection peak preceding a peak resulting from absorptivity, refraction and / or scattering.

15. A filter restriction sensing system comprising: An optical bubble sensor, the optical bubble sensor comprising light source; Light detector; as well as Sensor controller; wherein the sensor controller communicates signals with the light detector; Wherein, the sensor controller is configured as evaluating a signal received from the light detector; detecting bubbles based on a signal received from the light detector; and An estimate of restriction of a liquid filter upstream of the light detector is generated based on the detected bubbles.

16. A filter restriction sensing system as claimed in any one of claims 15 and 17 to 20, wherein: The sensor controller is configured to distinguish between bubbles and water droplets in the fluid based on at least one of a peak magnitude and a peak width.

17. A filter restriction sensing system as claimed in any one of claims 15 to 16 and 18 to 20, wherein: The sensor controller is configured to distinguish between air bubbles and water drops based on a ratio of peak magnitude to peak width.

18. A filter restriction sensing system as claimed in any one of claims 15 to 17 and 19 to 20, wherein: The sensor controller is configured to distinguish between air bubbles and water droplets based on a magnitude of a reflection peak preceding a peak resulting from absorbance, refraction, and / or scattering.

19. A filter restriction sensing system as claimed in any one of claims 15 to 18 and 20, in, The filter restriction sensing system is configured to generate an estimate of a restriction level of a fluid filter upstream of the light detector based on one or more characteristics of the detected air bubbles; as well as The characteristic of the detected bubbles includes at least one selected from the group consisting of: an average bubble size, a maximum bubble size, a bubble count, and a percentage of bubble volume to total fluid volume.

20. A filter restriction sensing system as claimed in any one of claims 15 to 19, wherein: The filter restriction sensing system is further configured to generate the restriction estimate using fluid flow through the filter.

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