Note: Descriptions are shown in the official language in which they were submitted.
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MULTI-MODAL FLUID CONDITION SENSOR PLATFORM AND SYSTEM THEREOF
FIELD OF THE INVENTION
PHI This invention encompasses embodiments for multi-modal integrated
simultaneous
measurement of various aspects of fluids contained in circulating systems such
as automotive
reciprocating engines and vehicle transmissions. These circulating systems
perform constant
internal lubrication, and heat and contaminant removal to protect the internal
moving parts
from the inherent friction and damage in normal operation. Most commonly this
is achieved
with fluids based on hydrocarbon and/or related synthetics, which, over time,
can lose their
protective properties, and vary in their perthrnifmce or breakdownidecay due
to internal and
external events. Several components within the lubricant fluid can be measured
and can
provide insight into the efficacy of the system to perform its designed
mission. Described
herein is a real-time, simultaneous, integrated, multi-modal sensor system for
early warning
notification:
BACKGROUND OF THE INVENTION
[0021 This field of invention is related, but not limited to, the
automobile industry. In
particular, the field relates to mechanical engines and large-scale mechanical
devices that
utilize motile lubricating fluids operating in high temperature environments.
For these
lubricants, it would be beneficial to monitor in real-time the changing fluid
properties, the
levels of contaminants, and changes in performance to ensure safe and reliable
operation of
the equipment being protected by the lubricating system. This approach applies
to
automotive vehicles, aircraft or spacecraft, industrial equipment, wind-
turbines, life-saving
medical machinery and other critical devices. The conditions of fluids are
often detected
using a static, periodic approach, typically requiring removing fluid from the
system, often
by extracting a sample of the fluid to send to testing laboratories around the
world, which
have established procedures and methods to measure a number of aspects of the
lubricating
fluid, including historical time-series of various parameters. It is common
practice to apply
such time-based longitudinal monitoring of the fluid to detect changes over
time to gain an
understanding of the changes in performance within the closed environment. For
example,
the presence of specific particles at increasing concentrations can indicate
levels of wear and
performance of certain underlying components within the system being
lubricated. "This
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testing typically measures changes in characteristics of the fluid over time,
including
detecting changes and deterioration of underlying lubricating fluid and
additives and the
detection of normal (expected) and abnormal (unexpected) "wear" of the moving
parts due to
normal operation. Static samples are usually sent to a facility that performs
a number of
tests, including detecting the presence of foreign materials and objects. In
some cases, such
as when the lubrication fluid is changed, the lubrication filter is commonly
sent as well as the
oil for testing and detailed analysis* For both the sample and the filter,
this is a destructive
"tear down" analysis ¨ such that the filter and the sample are not returned to
service, but
evaluated and subsequently removed. Tests typically performed in the
laboratory include
detection of metallic and non-metallic particles, presence of water or other
non-lubricant
liquids, carbon soot and other components, and in some cases, verification
that the
underlying chemistry of the lubricant is still intact. A written (pr
electronic) report is
generated and transmitted to the stakeholder upon completion of the testing.
Results typically
take days or weeks from extraction to stakeholder review.
NO31 A number of low-cost lubricating fluid measurement products and
techniques are
emerging onto the market --- including a consumer static "check" of a motor
oil sample (see
lubricheck,com) which measures the changes in electrical impedance
characteristics
(electrical capacitance and resistance when a small electrical source is
applied across the
sensor where a sufficient sample size of the lubricant bridges the sensor
electrode across to
the detector). This approach performs a single-dimensional measurement of oil
sump fluid
properties at a point in time in the evolution of the oil (i.e. a static
measurement), providing
insight only when the operator manually extracts a sample of oil to be tested
and only
indicates changes in the electrical properties should the data be
appropriately logged and
tracked over time. This approach has many drawbacks including the interval
sampling (only
when the operator makes a measurement), as well as the potential for
counteracting forces
from the presence of multiple contaminants introduced into the fluid to mask
the true
state/condition of the lubricant. As an example, in the case of an automobile
engine, the
normal operation of the combustion engine will produce carbon by-products as a
result of the
operation of the engine (this is what discolors the oil). If a vehicle were
producing only this
carbon "soot" the resistance would change (increase) due to the introduction
of the soot If at
the same time, the engine were undergoing adverse 'wear' to the extent that
small metallic
particles were produced as an abnormal condition across the internal moving
parts, these
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particles would decrease the resistance, as metal is a better conductor over
the base lubricant.
In the case where both soot and metallic particles were being produced at the
same time, they
could partially or completely cancel out some or all the measurable effects
thus providing a
false indication of the true condition of the lubricant and underlying engine.
A testing
laboratory analysis by comparison performs a number of tests which would be
able to
independently detect the presence of both materials in the base lubricant
fluid and provide an
accurate report of the condition of the fluid and the resulting system,
10041 Lubricating fluids have to accommodate a wide range of operating
conditions ¨
including variances in temperature, pressure, purity, and state change.
Lubricants are often
optimized for a specific operating environment and temperature range and are
expressed in
viscosity. Some lubricants are designed to operate with multiple viscosities
(e.g, 10W-30
multi-grade viscosity motor oil). Typically, measurement of the fluid
condition and
properties is static and performed externally outside this operating
environment via sampling
when in a static/non-operating state. Static sampling does not necessarily
validate the
condition of the fluid in the operating state ¨ either within or outside the
normal/typical
operating range. There are expensive and complex sensors that have been
developed for
measuring lubricating fluid and other liquids in real time ¨ either for use in
laboratory
environments and conditions or for very high-value machinery where immediate
sensor
lubrication information is critical. Companies such as Voelker Sensors, Inc.
offer a product
for the machine tool industry that measures in real time a number of
parameters including oil
level, oxidation (change in pH), temperature, etc. The sensor element is not
MEMS based
and has a larger footprint, and is not suitable in size/form factor for
operation within
automobile oil/lubrication systems ("Continuous Oil Condition Monitoring for
nachine Tool
and industrial Processing Equipment," Practicing Oil Analysis (9/2003).
R/051 Outside of the field of integrated-circuit multimodal sensor systems,
there have been
various implementations of continuous electrical property measurements as
performed by
Halalay (7,835,875, 6,922,064, 7,362,110), Freese et al., (5,604,441), Ismail
et at,
(6,557,396), Steininger (4,224,154), Marszalek (6,268,737), and others which
disclose
either a singular vector analysis (electrical) or a time series measurement of
electrical
properties to derive an understanding of the oil condition. The challenge
remains, as in the
Lubricheck approach, to overcome the interdependent and true measurement
cancelling
effects that can report an incorrect oil condition. This is precisely why the
fluid testing
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protocols and laboratories apply tests across multiple dimensions to include
spectral analysis
as well as tests to determine metal and other foreign object content in the
oil samples.
[006i Lubricants are designed to perform beyond their stated range and
are further
enhanced through the addition of "additives" to extend the lifetime and safety
margin of the
fluid. Understanding the lubrication longevity is crucial for the safe
operation of the system.
Replacement of the fluid is performed typically at very conservative (i.e.
short)
recommended intervals, providing a wide safety margin for the operator > In
general,
lubricants can operate for significantly longer intervals, or in the case of
specific equipment
operating in harsh environments (e.& military equipment used on the
battlefield or in mining
operations, etc.) may require a more aggressive replacement cycle. It is
important to
determine when the lubricating fluid cannot continue to perform according to
specifications
determined by the equipment/system manufacturers. As long as the lubricating
fluid is
within the safe margin of operation, it may operate indefinitely and not need
to be exchanged
or replaced with fresh lubricating fluid,
[0071 Providing a more precise measure of the fluid's performance can
maximize the
lifetime of both the lubricant and the equipment the lubricant is protecting.
As the cost of the
equipment and the hydrocarbon lubricant increase, so does the value of
providing both a
longer and more precise lifetime of the lubricant and early detection and
notification of
pending equipment performance deterioration (including motor, filter, and
other components
in the system, etc.). This approach can potentially save lives when critical
equipment failures
are detected in advance. In addition, should the fluid fail and contribute to
the equipment
breaking down, this system potentially eliminates the resources required and
time lost to
repair/replace the underlying/broken equipment. This approach also avoids the
loss of service
and resources required to complete oil changes more often than actually
needed,
SUMMARY OF THE INVENTION
10081 In embodiments, an integrated system is provided for continuous
monitoring of
multiple properties of a fluid derived from measurements from a plurality of
sensor
modalities within a fluid-based closed-system environment. Suitably the system
is an in
motor lubrication monitoring system and the monitoring is real-time.
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10091 In certain embodiments, the system is built into the form factor of a
standard size and
shaped oil drain plug found within a reciprocating engine oil drain pan,
wherein said system
is remotely located from a receiver by wired or wireless data telemetry.
Suitably the system
further comprises a remotely located receiver.
[0101 In further embodiments, the systems further comprises engineered
nanoparticles,
which when bound to target contaminants, provide a unique and measureable
signature and
can be captured and removed from circulation by a filtration device. Suitably
the
nanoparticles change state when one or more target environmental conditions
are met. In
en bodimentFõ the nanoparticles enable the detection of temperature excursions
beyond
designed operating specifications (i.e., temperatures higher or lower than the
operating
specification). In further embodiments, the nanoparticles enable the detection
of pressure
excursions beyond designed operating specifications (Le., pressures higher or
lower than the
operating specification). in additional embodiments, the nanoparticies enable
the assessment
of the performance of said filtration device,
[0111 In other embodiments, the sensor modalities comprise at least two of
electrical,
temperature, magnetic, optical, pressure, and multi-axis accelerometer
sensors, suitably at
least one of the sensor modalities comprises an inductor. In embodiments, the
sensor
modalities comprise at least magnetic and optical sensors and in other
embodiments the
sensor modalities comprise at least electrical, magnetic and optical sensors.
1012j In certain embodiments, the system is contained within an epoxy
encapsulation that
can support high temperature, high pressure, and high vibration environments
contained
within the oil drain plug mechanical design,
[0131 In certain embodiments, the system further comprises a limited
lifetime power source
that provides electrical energy to the electrical components of the sensor
platform, In some
embodiments, the system further comprises an energy scavenger/harvester that
provides
electrical power to a rechargeable power source for extended lifetime,
[0141 In certain embodiments, the system further comprises multiple digital
signal
processor modules fur detection of both single and multiple related fluid
characteristics, In
embodiments, the systems further comprise multi-stage output signal generation
selected
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from the group consisting of error indication, specific data signature
detection signal, specific
data signature signal detection strength level, and Fast Fourier Transform
(FFT) data output.
10151 In other embodiments, the sensor modality measurements are analyzed
using Kalman
Filtering techniques, Baysian analytic techniques, hidden-Markov Filtering
techniques, fuzzy
logic analysis techniques or neural network analysis techniques,
[016] In exemplary embodiments, the sensor modality measurements comprise
at least one
of the following: differential temperature comparison, differential magnetic
sensor
comparison, differential inductive sensor comparison, differential electrical
impedance
comparison, differential optical absorption comparison, multi-axis
accelerometer
comparison, any combination and integrated comparison consisting of at least a
set of two
sensors, data comparison of each sensor vector versus time and temperature,
data comparison
of an integrated vector consisting of a set of at least two sensors combined,
inductive data
comparison versus time and temperature, optical data comparison versus time
and
temperature, optical data comparison versus temperature and pressure,
temperature data
comparison versus time and pressure to detect peak heat, pressure data
comparison versus
multi-axis accelerometer data, and other sensor combinations.
[0171 Also provided are methods of continuously monitoring an operating
fluid of a
machine comprising: measuring a first condition of the fluid using a first
sensor modality,
measuring a second condition of the fluid using a second sensor modality,
filtering data from
the sensors, integrating the data from the sensors, analyzing the data from
the sensors,
deriving a property of the fluid from the data, transmitting the derived
property of the fluid
condition to a receiver, and repeating the process so as to accumulate a time-
series of a fluid
property that tracks changes in the operating condition of the fluid, In
embodiments, the
methods further comprise tracking the condition of the fluid by calculating
the time series
expected rates of change versus observed rates of change of any single or
multiple
conditions, In additional embodiments, the methods further comprise
calculating the
expected divergence or convergence across multiple sensor time series data of
anticipated
and expected measured value changes versus unexpected changes.
[018] Further embodiments, features, and advantages of the embodiments, as
well as the
structure and operation of the various embodiments, are described in detail
below with
reference to accompanying drawings,
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BRIEF DESCRIPTION OF THE FIGURES
10191 Figure is a representation of an exemplary real-time multi-modal
fluid sensing
system described in this application.
[020] Figure 2 is a representation of an exemplary major in-engine sensor
source and
receiving elements making up the multi-modal fluid sensor solution.
[021] Figure 3 is a block representation of an exemplary major electronic
and firmware
elements of the system presented within this application.
[022] Figure 4 is an inset diagram of exemplary optical sensors,
1023j Figures 5a and 5b are block diagram of illustrative, exemplary
processing electrical
and/or firmware elements comprising the Digital Signal Processing modules
incorporated
within the processing portion of the system presented within this application
for integrated
multi-rnodal sensor calculations,
f 024j Figure 6 is a representative framework of discrete wavelengths for
the various optical
properties detection.
[025] Figure 7 is a block representation of an exemplary power unit for the
system
presented in this application.
[026] Figure 8 is a representation of an exemplary real-time multi-modal
fluid sensing
system presented in this application in the exemplary form factor of a
standard oil drain plug.
DETAILED DESCRIPTION OF THE INVENTION
1027] It should be appreciated that the particular implementations shown
and described
herein are examples and are not intended to otherwise limit the scope of the
application in
any way,
[028] The published patents, patent applications, websites, company
names, and scientific
literature referred to herein are hereby incorporated by reference in their
entirety to the same
extent as if each was specifically and individually indicated to be
incorporated by reference
Any conflict between any reference cited herein and the specific teachings of
this
specification shall be resolved in favor of the latter, Likewise, any conflict
between an art-
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understood definition of a word or phrase and a definition of the word or
phrase as
specifically taught in this specification shall be resolved in favor of the
latter.
[029] As used in this specification, the singular tbrms "a," "an" and "the"
specifically also
encompass the plural forms of the terms to which they refer, unless the
content clearly
dictates otherwise. The term "about" is used herein to mean approximately, in
the region of,
roughly, or around. When the term "about" is used in conjunction with a
numerical range, it
modifies that range by extending the boundaries above and below the numerical
values set
forth. In general, the term "about" is used herein to modify a numerical value
above and
below the stated value by a variance of 20% it should be understood that use
of the term
"about" also includes the specifically recited amount.
Technical and scientific terms used herein have the meaning commonly
understood
by one of skill in the art to which the present application pertains, unless
otherwise defined.
Reference is made herein to various methodologies and materials known to those
of skill in
the art
10311 To provide a more accurate understanding of a fluid, conducting multi-
modal tests
simultaneously can help to give insight into the true operating status and
condition of the
lubricating fluid. In embodiments, an integrated system is provided for
continuous
monitoring of multiple properties of a fluid derived from measurements from a
plurality of
sensor modalities within a fluid-based closed-system environment. Suitable
embodiments
utilize a combination of advanced Micro-Electro-Mechanical Systems (MEMS) and
semiconductor techniques to place the laboratory tests directly into the fluid
to continuously
and concurrently measure multiple aspects of the fluid and report these
parameters
individually to a programmable computer to provide parallel and integrated
real-time
analysis of the fluid condition. As used herein the term "sensor modalities"
include
measurement of the magnetic, electrical and optical properties of a fluid as
well as measuring
the temperature and pressure of the fluid and monitoring the orientation of
the fluid and
surrounding containment vessel in space by measurement of multi-axis
acceleration. These
collectively comprise examples of "multi modal" analysis or tests throughout
the present
invention. These measurements can be done both individually and combined to
provide an
integrated insight into the condition and status of the fluid. As single-
dimension tests may
"obscure" any single result caused by the interplay between two different
contaminants in the
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fluid (e.g. the combination of both electrical resistance increasing and
electrical resistance
decreasing foreign matter in the system), the application of simultaneous
multi-modal
sensing using a plurality (Le., two or more) sensing modalities improves the
fidelity and
accuracy of the measurements.
To provide an enhanced understanding of the fluid conditions, in embodiments,
specially engineered nanoparticles are introduced, designed to enhance sensing
and capture
of undesired contaminants in the fluid as well as trigger an irreversible
property change upon
experiencing adverse conditions within the system. Specifically engineered and
designed
particles are either added to the fluid, or impregnated into the filter and
triggered/released
into the fluid flow in the presence of contaminants, including water, anti-
freeze, metal
particles, carbon soot, etc. The nanoparticles are not detected until a
triggering event. The
resulting combined or state-changed particle becomes measurable by the multi-
modal sensors
(plurality of sensor modalities) and provides a more sensitive wad complete
understanding of
the fluid condition. The resulting combined particle is also better collected
by specific filter
stages or by magnets (e.g. if paramagnetic) than the contaminant without
nanoparticles. This
process involves three primary steps-. first, the nanoparticles and their
surface attachments
are designed to activate in the presence of specific contaminant targets,
identified through
practice and through an understanding of the various contaminant conditions
that a
lubrication system may encounter. Second, the nanoparticles are introduced
into the
lubricating system, either as an additive or impregnated into the materials
within a filter,
nanoparticles are activated and subsequently detected by the multi-modal
sensor
system whilst in the operating environment. Further, the combination of the
nanoparticles
attached to the contaminant suitably becomes better filtered and removed from
active
circulation within the lubrication system. Alternatively, continued detection
and
measurement of nanoparticles by the multi-modal sensor may indicate a partial
or full failure
of the fluid filter,
Nanoparticles can also be released into the fluid during normal operating
conditions.
In such an embodiment, nanoparticles can be designed to change state if any
part of the
lubrication system exceeds a target operating condition. For example, such
nanoparticles can
be designed to change state irreversibly if excessive temperatures are
experienced anywhere
within the engine lubrication system. The environmentally induced change in
nanoparticle
properties can later be measured and recognized to indicate that some part of
the machinery
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may be overheating. For example, the surface properties of the nanoparticle
can be altered
under thermal stress. The changes in surface properties can be recognized by
the sensor
system, alerting the system of an excessive temperature in a part of the
system that otherwise
would remain unmeasured. The particles can, for example, be designed to change
fluorescence, paramagnetism or other physical or chemical property
irreversibly above a
target temperature. If any part of the system or component exceeds this design
temperature,
these particles irreversibly change state. The changed state can be measured
at a single point
in the system, such as at the multi-dimension sensor. This approach enables a
continuous
indication of temperature limit at every point in the lubrication system. It
provides a benefit
equivalent to mounting temperature sensors all over the internal environment,
but at much
lower complexity using fewer resources.
[0341 In
embodiments, the engineered nanoparticles themselves serve as lubricating
material, as their inherent precursor is based on a carbon nanostructure that
has friction
reducing properties. Nanoparticles as well have the inherent property of
increasing the
surface area/coverage, which improves the sensor detection (e.g. over-
temperature condition
detection) as well as improve the lubricating coverage within the system. In
certain
embodiments, the nanoparticles encompass metallic nanoparticles, which are
coated with a
thin (e.g, about 2 am) layer of graphitic carbon that allows the covalent
chemical
functionalization of this carbon to result in chemically functionalized
magnetic beads. In
other embodiments, the nanoparticles encompass metal magnetic nanoparticles
including, for
example, cobalt, iron, nickel and alloys. In certain embodiments, the reactive
metals are
covered by graphene-like carbon layers. In certain embodiments, the inert
nature of carbon
results in a core-shell magnetic material exhibiting an extremely high thermal
and chemical
stability. In certain embodiments, the nanobeads can be applied in harsh
conditions, such as
low pH and high temperatures, without the problem of the oxidation of the
metal core. In
other embodiments, the nanoparticles include covalent finictionalization of
the metal
nanomagnets, In certain embodiments, the binding relies on carbon-carbon
bonds, so no
ligands are lost even under demanding process conditions (e.g., high
functional loading). The
wide range of functionalization allows the preparation of beads with custom
surface
functionalities, in particular embodiments, the nanoparticles are magnetic
beads with
covalently functionalized aromatic groups, catalysts and protective groups.
The highly
magnetic properties allow a high recyclability of the magnetic chemicals for
reuse.
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[035] In multi-modal sensing, measurements are combined to determine the
state (and state
changes) for the fluid using software/firmware programming to compare sensor
inputs
against reference datum and to detect changing fluid conditions across various
measurement
dimensions, including time. It is important to set thresholds for detection of
foreign
contaminants in the oil. For example, a sufficient quantity of water over time
can cause
corrosion of critical elements normally protected by the lubricating fluid.
Based on these
thresholds, certain alerts and notices can be provided, either transmitted
through an output
interface or polled by a wireless interface, optionally using a portable hand-
held device, such
as a smart phone. To validate the ongoing assessment of the fluid condition, a
secondary
check can be done to verify the measurements through periodic laboratory
sampling,
External validation can be part of the conforming calibration process during
initial testing of
the multi-modal sensors. External validation can also qualify additional
lubricating fluids
and operating environments. Once the baseline is understood, the thresholds
across all the
integrated measurements can be programmed into the semiconductor to provide
the alerting
functionality over and beyond the integrated measurement data outputs,
[036/ In additional embodiments, the systems and methods described herein
detect use of
the wrong fluid or unsuitable lubricating fluid that may be mistakenly
introduced into the
lubrication system. Operating machinery with the wrong lubricating fluid can
cause
irreparable harm if not immediately remediated. The multi-modal sensor
'expects'
lubricating fluid to be conforming, raising an alert when non-confornaing
fluid is introduced
and subsequently detected,
10371 Specific individual sensors can be combined into a framework that
provides a much
more complete understanding of the state of the system, both for immediate
measurement as
well as longitudinal monitoring. Such sensor frameworks greatly improve real-
tin-le
monitoring of system conditions and greatly improve the ability of the system
to
automatically recognize and respond to a variety of operational events,
[038] hi particular, frameworks incorporating magnetic sensors facilitate
the timely
recognition of ferrous metal contaminants, Alternatively, such magnetic
sensing can detect
magnetic nanoparticles. Other sensors in the framework can distinguish between
the two.
For example, paramagnetic resonance can characterize the nature of the ferrous
particles, and
potentially their size
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[0391 Integrating optical transmissometers, opacity measurements or
spectral measurements
into the framework provides an indication of particular contaminants, for
example, soot,
water, or antifreeze solution, integrated with nanoparticIe sensing, detection
of
contaminants can be enhanced. Further the invention can be improved through
the
incorporation of multi-modal sensing analysis to include for example pressure
and
temperature that may change the optical properties of the fluid. These
correcting factors can
be applied to improve the accuracy of the measurements.
[040] Integrating electrical measurements into the framework provides a
more complete
picture of the fluid condition. These measurements can also detect and can
provide
independent ways to distinguish between alternative fluid status and condition
diagnoses.
These measurements can also detect narxoparticles, and can provide independent
ways to
distinguish between alternative fluid status and condition diagnoses. Nano-
particles can be
engineered to be activated under specific conditions and circumstances ¨ such
as a high
temperature incursion ¨ that irreversibly change its state. This state change
is detectable by a
set of at least one of the sensor modalities.
10411 A control system integrates disparate sensors, utilizing patterns of
sensor conditions
to "recognize" or "diagnose" sets of conditions worthy of further attention.
Established
mathematical algorithms for such analysis include and are not limited to
Kalman filtering
(and enhanced Kalman filtering), hidden-Markov models, Bayesian analysis,
artificial neural
networks or fuzzy logic. These control systems can be implemented readily in
software,
firmware or hardware, or a combination thereof, (See: "Solutions for MEWS
Sensor
Fusion," Esfandyari, J, De Nuccio, R, Xu, G., Solid State Technology, July
2011, p. 18-21;
the disclosure of which is incorporated by reference herein in its entirety)
/0421 In further embodiments, additional understanding of the fluid
properties under
different machinery operating conditions can be gained, for example, including
"at rest"
when the system is not operating, or at "peak heat," which may actually occur
after the
system shutdown. Temperatures may increase after shutdown when no cooling
fluid is
circulating. Fluid properties will change as the fluid heats and cools.
Measuring these
changes across the short heating or cooling interval can yield valuable
additional indications
and insights into the properties of the lubricating fluid. For example,
optical absorption may
vary as the fluid heats. In addition, tracking the change in electrical
properties with
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temperature can provide further information as to the condition of the fluid.
Deviations may
cause the control system to request measurements not only when the machinery
is operating
but also upon startup or shutdown, for example,
f043) The present application overcomes a number of limitations of
traditional diagnostics.
First, the traditional time delay from fluid sampling to testing may place
critical equipment at
risk of damage. Sometimes the lubricating fluid is sampled at the time it is
being exchanged.
While potentially useful for providing insight into the wear of internal
parts, machinery may
be operated in a potentially unsafe condition until the results are returned
from the
laboratory. Second, the lubricating fluid may be exposed to extreme
temperatures during
operating transients, which can be often in excess of 150 degrees C,
potentially causing some
breakdown of additives in the lubricating fluid. Such problems are not usually
detected, as
the equipment often is "turned off' during these conditions. Although there is
no new heat
being generated, residual heat is transferred into the lubricating fluid and
can potentially
impact its performance. Such temperature extremes often require special
engineering effort to
design integrated in-situ sensing systems to support reliable operation (e,g.
from -50 C to +
150 C). Further, sensors and other electrically active elements need to
support this
environment, Equally important is the support of various pressures that the
lubricating fluid
may experience during normal and high-load operations. An in-situ sensor
framework must
be designed to withstand the peak temperatures and pressures experienced
within the
lubrication system over time.
[0441 Several variables provide insight into lubrication fluid properties.
Some variables can
be measured directly while others can be derived. To achieve a basic
understanding of fluid
condition, several measurements (sensor modalities) of the lubricant may be
helpful,
including, for example, temperature, absolute pressure, electrical impedance
or resistance,
p1-1, optical transmission or absorption, and magnetic measurements.
Measurements are
either direct (e.g, temperature via a temperature sensor) or derived --- such
as degree of carbon
buildup via combined measurement of electrical and optical changes. Standard
techniques
are available and used today such as thermocouples and pressure sensors to
acquire some of
these data points. Derived measurements (e.g. viscosity conformance within
operating
range) can be calculated from direct measurements, and can be. extrapolated
over ranges of
temperature and pressure. Additional detection methods include the use of one
or more
inductive coils and magnetic sensors to enhance detection of moving metallic
particles. An
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optical transmissometer, comprised of an optical light source and optical
detector, for
example, measures the changes in absorption of optical light at various
wavelengths to
characterize carbon soot buildup and other potential contaminants and
materials in the
lubricating fluid. All such measurements should be temperature and pressure
compensated
(or normalized) to provide an accurate indication of the underlying health of
the lubricating
fluid. Further, pressure measurements can be qualified for changes in the
system orientation,
Computation of orientation from multi-axis accelerometers is used to determine
when a
pressure reading may be invalid due to the system being oriented beyond a
predetermined
standard, or alternatively the pressure reading is compensated for a system
orientation within
predetermined limits of such a standard.
[045] Viscosity analysis derives a frictional index from multiple sensor
readings to
determine the net fluidic friction of the lubricant. This invention presents a
simple method of
deriving viscosity by measuring, for example, two magnetic sensors within the
fluidic
lubricant in a selected site to measure fluid flow. These magnetic sensors,
such as no-latency
Hall sensors, are substantially similar and located in close proximity to one
another within
the lubricant flow. A small turbulence inducer enables measurement near the
sensors of slight
differences in flow based on induced flow perturbation. This measure can be
further
integrated with optical absorption measurements using the optical
transmissometer. This
integrated measure, coupled with temperature or qualified pressure readings,
provides a
framework for calculating the frictional index. The Hall-based sensors are
designed to be as
similar as possible. Temporal and spatial variations not caused by the
turbulence inducer are
subtracted using the two nearly identical sensors Further, the shape of the
turbulence inducer
is designed to create subtle changes related to the fluidic velocity,
analogous to aeronautical
applications in which fluid molecules travel at slightly different speeds
above and below an
airfoil. Viscosity can be derived from these slight difference measurements
along with the
local temperature and pressure, using documented lubricant viscosity reference
data,
providing an indication of real-time lubricant conditions.
[0461 Sensors are suitably designed to withstand high temperatures of the
engine lubricant.
High-temperature thermocouples measure temperature, thick-film resistors
enable pressure
sensing, and high-temperature magnetic sensors. The optical measuring methods
are based
on proven high-temperature designs. The optical spectivin suitably ranges from
'UV to mid-
IR in which the lubricating fluid is not emitting energy at high temperature,
depending on the
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fluid and the environment and potential contaminants The transmissometer range
is
measured in millimeters and the distance between the emitting element and the
receiving
element is precisely controlled using known MEMS manufacturing tecimiques.
This distance
between the optical emitting and receiving elements must be very accurate All
of these
elements have been implemented and operate individually within these extreme
temperature
and pressure environment in such a manner as to relay useful data. The design
is not limited
to these methods. At present, these methods are proven effective and provide a
simple
solution.
[0471 In embodiments, the systems and methods described throughout provide
real-time
monitoring of fluids such as those associated with high-temperature
environments present
within or associated with internal combustion engines (i,e, monitoring the
fluid during
engine activity without the delay of removing a sample). Suitably, the systems
and methods
monitor oil-based fluid lubricants normally used with internal combustion
engines, as well as
other fluids such as transmission fluids or glycol-based coolants such as
antifreeze, and other
fluidsin manufacturing environments and critical life-saving medical equipment
used in the
healthcare industry. The systems and methods suitably provide real-time
monitoring using
multiple sensor modalities to determine the degradation of the monitored fluid
under various
operating conditions. Another aspect is the ability of the invention to detect
the presence of
known harrnful particulates, such as metal, within the lubricant. Another
aspect addressed is
monitoring fluid with a sensor module that is continually submerged within the
lubrication
fluid. Another aspect addressed is the parallel and integrated real-time
analysis of the fluid
condition. Another aspect addressed is the introduction of specifically
engineered
nanopartieles that are designed to enhance sensing and capture of contaminants
and adverse
operating conditions. This invention also addresses high temperatures and
other conditions
experienced in the operating environment of such .machinery.
10481 In exemplary embodiments a real time multi-modal fluid sensing system
is in a self-
contained embodiment of a single unit comprising an active sensing environment
(100)
intended to be submerged in the fluid to be monitored. The sensors are
attached to an
assembly that can be placed into the fluid with the electronic and active
sensors embedded
into a oil drain plug (300) that is held in place via a threaded bolt (200).
The bolt head
accommodates the non-sensor elements of the self-contained system, called the
command,
control and communications module, C3 module (400) to include the
microcontroller, filters
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and other elements. Also suitably contained within the assembly are inductor
coils (108) and
other methods of signal source to include power to operate the system, such as
a power
source (180). The bolt assembly is a self-contained platform that can be
installed and
removed by a technician. Such an environment is -typical of an oil drain plug
on an
automobile or a similar "low point" in a lubricating return system that may
also serve as a
reservoir for the fluid. The fluid environment may be subject to changes in
temperature and
pressure through normal and abnormal operations. As such the sensors are
designed to
operate within the temperature and pressure specifications ¨ as well as
customary tolerances
beyond the normal operating environment to be able to detect abnormal
conditions.
10491 Within the sensing environment the system programmatically generates
its own local
and low energy reference signal sources across multiple sensor modalities
including
magnetic, optical and electrical, and continuously detects values therein as
well as passively
receives continuous pressure and temperature measurements. The active elements
of the
sensor platform (100) are intended to be submerged in the fluid under
measurement. In the
case that the sensor is not submersed, either completely or partially into the
fluid, this can be
detected and confirmed through multiple sensor confirmation across the optical
(106)
transmission to optical reception (107) as well as electrical source (101) to
reception (104) of
expected value tolerances. In this way the condition of lack of fluid can be
detected by
multiple approaches, as well as verify that both the electrical and optical
sensors are correctly
and collaboratively cross-checked.
[0501 Magnetic sensing is achieved through generating a signal of a pre-
defined and
programmable characteristic (102) that has a known fixed reference distance
within close
proximity to the magnetic sensors (103) that is received and processed by a
data acquisition
control unit (109) that performs signal amplification, AID conversion and data
filtering. The
sensing can be accomplished by one or more sensors (103) of a type such that
provide a
response rate commensurate with the signal, that can be the same type or
different and
provide both direct and differential measurements of the fluid condition. The
data
acquisition control unit (109) performs the steps to filter and analyze the
signals, including
amplification, noise reduction filtering which is then communicated to the
rnicrocontroller
(140). Magnetic measurements when coupled with other measurement dimensions
allow for
both a confirmation of a detected condition as well as a vector for detection
of exception
conditions such as a paramagnetic Nmo-particle that upon activation develops a
magnetic
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signature that can be detected. The Nano-particle activation is independent of
the sensors
and is triggered upon an exception condition - such as an extreme temperature
limit being
exceeded, etc.
[051] One or more optical sensors (107) can be coupled to one or more
optical source(s)
(106) which can consist of one or more specific optical wavelength emitters
such as narrow
frequency tuned light emitting diodes (LEDs) and optical receivers such as
photoreceptors.
Today's optical emitters can be configured to emit light in narrow frequency
bands. Such
wavelengths are dependent upon the specific types of fluid and contaminants
that may
accumulate within the fluid. Figure 6 shows a representative map over the near
infrared
region of such. The optical sensing can determine a number of characteristics,
including but
not limited to the presence of fluid, when the LED is emitting. Further the
LEDs can be
placed at different known and fixed distances from accompanying photoreceptors
to provide
a distance based profile of the level of absorption across different
frequencies. The
embodiment can be accomplished by a single LED emitter to photoreceptors at
known
distances as well as multiple LEDs spaced at known distances from the
photoreceptor pulsed
in a known sequence. The controlling logic is managed through
software/firmware in the
microcontroller (140) and in the data acquisition control unit. (109). Optical
sensing can
detect the difference in both the specific wavelength absorption and time
series changes in
optical characteristics. The optical sensing developed operates in both an
active and passive
mode. In the active mode the optical source pulses light of known strength and
wavelengths
through the fluid to measure the degree and level of absorption of the light
from its source.
This small scale transmissometer is configured to detect the specific
contaminants and/or
changes such as a breakdown in the fluid properties across specific
wavelengths, such as
shown in Figure 6. Another mode of operation is to detect optically activated
Nano-patticles
that have been triggered by an exception event such as a temperature
excursion. In this mode
a signal source (such as, but not limited to, a specific wavelength optical
trigger as well as an
electrical trigger or magnetic trigger) cause the specifically engineered Nano-
particle to
fluoresce at a specific frequency that can be subsequently detected by the
optical sensors
(107). Optical emitters can be pulsed in a programmatic sequence such that a
common
photoreceptor can be applied as the sensing receiving point and the software
in the
microcontroller can associate the emitter frequency to the signal response
received by the
optical photoreceptor sensor, Further, Nano-particle activation is independent
from the
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sensing, The triggering method for the Nano-particle if activated can be
independent from an
optical trigger, e.g, a Nano-particle can be triggered to fluoresce upon a
magnetic or electric
field source as its trigger, which is provided by the multi-dimensional
sensor.
[052] Sensing changes in the electrical properties is accomplished by an
electric source
(101) placed at known reference distance from an electric capacitive measuring
such as the
constant of dielectric of the fluid. The strength and frequency of signal and
measurement is
based on the programmable microcontroller firmware and, is based and dependent
on the
underlying characteristics of the fluid to be continuously monitored which
lies between the
source and measurement sensing. The electric resistance and capacitance can be
measured
across the gap via the data acquisition control unit (109). Different fluids
will have different
properties, and thus the ability to programmatically configure and control
both the source
field and sensor receiving properties is an important aspect of this
invention. Pressure sensing
(111) and temperature sensing (110) are also connected to the data acquisition
control unit
(109) These sensors can also detect normal and abnormal conditions in heat and
pressure
levels and provide insight to the operating status of the environment, Fluid
condition
changes ¨ such as at rest (when the system is not operating) through the peak
operating
environment ¨ can be evaluated by the programmable microcontroller unit (140).
Such
applications can be developed in software/firmware to include developing an
understanding
of both "at rest" and "in operating" conditions, Further, the profile at
specific pressures and
temperatures can be useful for both determining calculations (offsets due to
temperature/pressure ¨ such as if magnetic sensors are based on using the Hall
Effect (103))
as well as optical property changes due to temperature and pressure profiles.
Further, the
detection of Nano-particles can be triggered by the introduction of an
electrical signal of a
certain characteristic such as a frequency, which facilitates detection either
by magnetic or
optical modalities.
[053] Tracking changes in the orientation of the oil drain plug (300) of
Figure 1 in three-
dimensional space is accomplished by multi-axis accelerometer sensors (112).
Note that in
alternative embodiments, accelerometer 112 may be disposed in the C3 module
(400),
MEMS sensor platform (100), receiver (170), or other external location, The
accelerometer
sensor (112) may be disposed in the MEMS device (100), in the non-sensor
elements of the
self-contained system, called the command, control and communications module,
C3 module
(400), or near another processor unit. The acceleration of each axis of
interest is measured
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by the data acquisition control unit (109) and used to compute the orientation
of the oil drain
plug (300), and therefore the orientation of the engine and of the vehicle in
space. The
orientation computation can be used by the data acquisition control unit (109)
to qualify the
measurements from the pressure sensors (111) and reject certain pressure
readings or make
adjustment to certain pressure readings to compensate the pressure output,
according to
predetermined standards of orientation.
[054] A real time clock (150) provides an accurate time basis to trigger
monitoring events
by the microcontroller module (140) and associate acquired data with a time
basis for
longitudinal analysis. The real time clock provides both time and date
information that can be
associated with each of the recorded multi-modal sensor measurements.
[055] The programmable microcontroller (140) also provides both pre and
post processing
of information including the use of filtering and other algorithms to provide
data correction.
The results are communicated via a communications module (160) either via a
wired or
wireless connection to a receiver (170). Note that receiver 170 may optionally
comprise a
display, a processing unit, or both, receiving data from the integrated
system. Both the
receiver (170) and the microcontroller may possess internal storage (280) to
record and
evaluate time-series data.
[056] Within the microcontroller (140) sensor data is accumulated and
subject to additional.
filtering and integration across the multiple sensors. The raw data is subject
to processing by
a set of at least one digital signal processor (DSP) for each of the
individual sensor modalities
such as temperature, pressure, optical absorption, electrical impedance and
magnetic
signature (203, 204, 205, 206, 207 and 208). A parallel output of the results
¨ both pre and
post data correction filtering (220) provides both a raw data output (260)
that can be
communicated via a communications module (160).
[0571 A configuration module (270) can dynamically set filtering and
processing
parameters to the enhanced filtering (220) to include baseline and error
conditions as well as
other parameters including configuring storage, event monitoring, triggers,
etc. The
configuration module is connected via the communications module (160) to an
external
device.
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[0581 A Nano-state detector (240) is a continuous check for any triggered
and activated
Nano-particles that exhibit a signature across a set of at least one of the
sensors. This
includes the detection of any active signature as profiled and programmed into
the
microcontroller. The state detector evaluates the outputs of the DSP
processing from a set of
at least one sensor and integrates real time characteristic (230) data and
associated filtering
and integrated characteristic data. The Nano-state detector as well provides
output to the
display (260) and storage (280) as well as can receive configuration
parameters via the
configuration module (270),
P591 Further, during operation that can be either continuous or polled at
intervals as
directed by the microprocessor and associated programming software, and
further enhanced
by the inclusion of a real time clock to provide an accurate time basis (150).
Such
measurement "cross checking" provides for both inherent value confirmation,
improves that
data correction (by example Kalman filtering and other algorithmic techniques)
and overall
sensor system integrity. For many high value systems when a "fault" is
detected, often the
failure is not in the environment, but the sensor. This invention provides for
the cross-
correlation and verification of the inherent sensor platform by continuously
validating across
a number of the measurement criteria such that expected and anticipated sensor
output/values
can continuously validate the sensor system performance. In this way the
isolation of the
error condition (e.g. the sensor failure) is in itself a valuable operator
insight ¨ to identify and
replace a faulty sensor as a known failed device,
[0601 A power source (180), comprising electrical storage (182) and an
optional energy
harvester, provides electrical power to the C3 module (400) and sensor
platform (100). In
one embodiment, the electrical storage comprises a battery that provides power
to the system
until it is discharged, in another embodiment, the electrical storage
comprises a rechargeable
battery connected to one or more energy harvesters, which extend the lifetime
of the
electrical storage beyond a single charge. In another embodiment, the power
storage
comprises an electrical double layer capacitor, optionally coupled to an
energy harvester that
extends the lifetime of the electrical storage beyond a single charge,
[0611 in one embodiment, the energy harvester comprises a vibration energy
harvester
(183) that converts kinetic energy from the environment into an electrical
current. In another
embodiment, the energy harvester comprises an acoustic energy harvester (184)
that converts
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audible or vibrational energy into an electrical current. In another
embodiment the energy
harvester comprises a thermal energy harvester (185) that converts
differential temperatures
into an electrical current. In another embodiment the energy harvester
comprises an
electromagnetic energy harvester (186), where an antenna (188) collects
background
electromagnetic radiation, such as RF transmissions, for conversion into an
electrical current.
[062] The C3 module (400) communicates with the Receiver (170) using either
wired or
wireless protocols, or both. Suitable protocols exist in automotive systems
today, such as
Controller Area Network bus (CAN) and Local Interconnect Network bus (UN) for
wired
communications, and Tire Pressure Monitoring System (TPMS) and Remote Keyless
System
(RKS) for wireless communications, The Receiver (170) in some embodiments
could
comprise a processing unit. bt could also comprise a display for depiction of
the monitoring
status,
[063] The mechanical design for sensing changes in fluid parameters in-situ
incorporates
unique features to minimize costs and provide an environmentally sound design
for long life.
The concept is to include a pressure sensor device built into the oil drain
plug that allows for
simple installation for upgrades and replacement on scheduled maintenance
schedules. The
sensor is mounted with an epoxy polymer resin that has an excellent operating
temperature
range, adherence properties, and resistance to salts and petroleum by
products. This is a key
to prevent issues with differential thermal expansion, delamination, and
chemical breakdown.
The bolt has a standard thread size based on the end users specification. A
hole is drilled
through the middle of the bolt to allow for installation of the integrated
system and to provide
a path for the oil to reside over the sensor platform (100). The outside of
the pressure sensor
is open to the atmosphere via an integrated atmospheric pressure pipe (314).
The head of the
bolt is machined down to fit the sensor into the bolt by creating a cavity.
P641 Fig. 7 depicts a power source comprising energy storage (182) and/or
an energy
harvester (183-186) for adding to the energy storage (182). Such energy
harvesters could
collect vibrational energy (183), especially from the oil pan of an operating
engine, or
acoustic energy (184). Many embodiments also comprise a thermal gradient
between fluid
pan and the environment, in which harvester (185) could comprise a TEC (Thermo-
Electric
Convener) for the conversion of thermal to electric energy, as is known to
those of skill in
the art. Alternatively, Electromagnetic Harvester (186) could collect energy
from any one of
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electric field, magnetic field, inductive, wired or wireless electromagnetic
energy, optionally
using antenna (188).
1065i Fig. 8 depicts an overall cutaway view of the oil drain plug multi-
modal sensor
system, showing one particularly favorable embodiment of the present
invention, including
C3 module (400), integrated MEMS sensor platform (316, equivalent to sensor
platform
100), and battery (180). RF antenna (310) provides communications and in some
embodiments performs the energy havesting of antenna (188). Printed circuit
boards (312)
shown in cutaway view provide one or more substrates and electrical coupling
for C3 module
(400) and MEMS sensor platform (316 or 100). Ambient pressure pipe (314)
conveys the
ambient pressure to a differential pressure sensor disposed in this embodiment
on sensor
platform (316). Note that other embodiments could use an absolute pressure
sensor in place
of this differential sensor, with or without an additional ambient pressure
sensor to enable an.
electrical compensation as opposed to mechanical pressure compensation.
Temperature
compensation is also known to those of skill in the art for these pressure
sensors to improve
accuracy and repeatability. Bolt threads (200) provide a conformal drop-in
replacement for a
traditional oil drain pan bolt in some preferred embodiments,
10661 in one embodiment, this sensor system measures the pressure near the
bottom of the
fluid reservoir, and optionally compares this pressure to ambient pressure.
Optionally
temperature compensation may be included for this measurement. This approach
can
measure the mass of fluid in a column above the sensor corresponding to the
static pressure
in a gravitational (or accelerational) field. For a given temperature, this
static pressure
approximates the level of the fluid at a particular temperature and
orientation of the fluid-
containing vessel.
10671 The foregoing description, for purpose of explanation, has been,
described with
reference to specific embodiments. The illustrative discussions above,
however, are not
intended to be exhaustive or to limit the invention to the precise forms
disclosed. Many
modifications and variations are possible in view of the above teachings. The
embodiments
were chosen and described in order to explain the principles of the invention
and its practical
applications, to thereby enable others skilled in the art to best utilize the
invention and
various embodiments with various modifications as are suited to the particular
use
contemplated.
