Patent Description:
A typical fuel dispensing environment, such as the forecourt of a retail fuel dispensing station, comprises a large number of components both for fuel handling and for conducting fuel dispensing transactions. Examples of such components include fuel dispensers, fuel piping, underground storage tanks, submersible turbine and self-contained pumps, motors, and dispensing nozzles. Further, fuel dispensers themselves typically contain flow meters, pulsers, control electronics, valves, card readers, manifolds, and internal fuel and vapor recovery piping, among many others. Many of these components are subject to regulatory requirements to maintain a high degree of accuracy and safety and to guard against environmental impact.

As is well known, for a variety of reasons, these components require periodic maintenance or replacement. Some of these components tend to wear over time, which can cause a loss of accuracy or efficiency in a fueling transaction or other operational issues. Component wear can be caused by manufacturing defects, poor fuel quality, or excessive use, among other causes. Eventually, the components may fail leading to downtime while the components are replaced. Further, some of the components may fail to operate properly, leading to customer frustration or the inability to complete a fueling transaction. Moreover, it will be appreciated that there is the potential for fraud with respect to some of these components, such as a fuel flow meter, pulser, and the control electronics. <CIT> discloses a fuel dispenser that receives fluid from a fuel source and dispenses the fuel to an output device while metering the quantity of fuel dispensed to the output device. <CIT> discloses a measured fluid delivery apparatus.

The present invention recognizes and addresses various considerations of prior art constructions and methods. The present invention provides a fuel dispenser according to claim <NUM>. Devices disclosing fuel dispensers with fuel flow piping leading to a fuelling nozzle, a filter manifold for mounting a fuel filter and a sensor device for sensing properties of the fuel to be dispensed are shown in <CIT> or <CIT>.

In one embodiment the sensor device has a body defining inlet and outlet flow passages therethrough. The body in this case may further define a threaded hole for attachment to a first filter mount of the manifold and a second filter mount for attachment of the filter thereto.

In one embodiment the electronics are operative to transmit the signal wirelessly via an associated antenna. The antenna may be covered by an antenna lens.

The sensor may include one or more pressure sensors operative to detect differential pressure between inflow and outflow of the filter manifold. For example, the one or more pressure sensors may comprises a micro-electromechanical system (MEMS) differential pressure sensor positioned to be in fluid communication on a first side thereof with a fuel filter inlet and on a second side thereof with a fluid filter outlet.

Embodiments are also contemplated in which the sensor device comprises a power generator to produce power for its operation. For example, the power generator may comprise a turbine power generator that creates electrical energy during fuel flow. One or more energy storage components such as at least one capacitor and/or at least one battery may also be provided.

The present invention provides a multi-mode hydraulic sensor (MHS) device for use in a fuel dispenser. The sensor device comprises a body mountable along a fuel flow path in the fuel dispenser. A plurality of different sensors are operative to detect a sensed condition related to the fuel dispenser. The sensor device further comprises electronics to transmit a signal related to the sensed condition, the electronics including a radio to transmit the signal wirelessly via an associated antenna.

Those skilled in the art will appreciate the scope of the present invention and realize additional aspects thereof after reading the following detailed description of preferred embodiments in association with the accompanying drawing figures.

A full and enabling disclosure of the present invention, including the best mode thereof directed to one skilled in the art, is set forth in the specification, which makes reference to the appended drawings, in which:.

Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the invention.

Reference will now be made in detail to presently preferred embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention.

For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the present disclosure including the appended claims and their equivalents.

Some embodiments of the present invention may be particularly suitable for use with a fuel dispenser in a retail service station environment, and the below discussion will describe some preferred embodiments in that context. However, those of skill in the art will understand that the present invention is not so limited. In fact, it is contemplated that embodiments of the present invention may be used with any fluid dispensing environment and with other fluid dispensers. For example, embodiments of the present invention may also be used with diesel exhaust fluid (DEF) dispensers, compressed natural gas (CNG) dispensers, and liquefied petroleum gas (LPG) and liquid natural gas (LNG) applications, among others.

<FIG> is a perspective view of an exemplary fuel dispenser <NUM> according to an embodiment of the present invention. Fuel dispenser <NUM> includes a housing <NUM> with a flexible fuel hose <NUM> extending therefrom. Fuel hose <NUM> terminates in a manually-operated nozzle <NUM> adapted to be inserted into a fill neck of a vehicle's fuel tank. Nozzle <NUM> includes a fuel valve. Various fuel handling components, such as valves and meters, are also located inside of housing <NUM>. These fuel handling components allow fuel to be received from underground piping and delivered through hose <NUM> and nozzle <NUM> to a vehicle's tank, as is well understood.

Fuel dispenser <NUM> has a customer interface <NUM>. Customer interface <NUM> may include an information display <NUM> relating to an ongoing fueling transaction that includes the amount of fuel dispensed and the price of the dispensed fuel. Further, customer interface <NUM> may include a display <NUM> that provides instructions to the customer regarding the fueling transaction. Display <NUM> may also provide advertising, merchandising, and multimedia presentations to a customer, and may allow the customer to purchase goods and services other than fuel at the dispenser.

<FIG> is a schematic illustration of internal fuel flow components of fuel dispenser <NUM> according to an embodiment of the present invention. In general, fuel may travel from an underground storage tank (UST) via main fuel piping <NUM>, which may be a double-walled pipe having secondary containment as is well known, to fuel dispenser <NUM> and nozzle <NUM> for delivery. An exemplary underground fuel delivery system is illustrated in <CIT>. More specifically, a submersible turbine pump (STP) associated with the UST is used to pump fuel to the fuel dispenser <NUM>. However, some fuel dispensers may be self-contained, meaning fuel is drawn to the fuel dispenser <NUM> by a pump unit positioned within housing <NUM>.

Main fuel piping <NUM> passes into housing <NUM> through a shear valve <NUM>. As is well known, shear valve <NUM> is designed to close the fuel flow path in the event of an impact to fuel dispenser <NUM>. <CIT> discloses an exemplary secondarily-contained shear valve adapted for use in service station environments. Shear valve <NUM> contains an internal fuel flow path to carry fuel from main fuel piping <NUM> to internal fuel piping <NUM>.

After fuel exits the outlet of shear valve <NUM> and enters into internal fuel piping <NUM>, it may encounter a replaceable fuel filter <NUM> mounted via a filter manifold <NUM>. As one skilled in the art will appreciate, fuel filter <NUM> functions to remove debris entrained in the flowing fuel before it reaches other fluid handling components in the fuel dispenser. Fuel filter <NUM> may also be designed to remove some water that may be present in the fuel. In this case, a multi-mode hydraulic sensor (MHS) <NUM> is positioned between filter <NUM> and manifold <NUM>. MHS <NUM> advantageously uses the filter mount of manifold <NUM> as a convenient and effective manner of locating MHS <NUM> along the fuel flow path.

After fuel passes through filter <NUM>, it flows toward a flow control valve <NUM> positioned upstream of a flow meter <NUM>. Alternatively, valve <NUM> may be positioned downstream of the flow meter <NUM>. In one embodiment, valve <NUM> may be a proportional solenoid controlled valve, such as described in <CIT>.

Flow control valve <NUM> is under control of a control system <NUM>. In this manner, control system <NUM> can control the opening and closing of flow control valve <NUM> to either allow fuel to flow or not flow through meter <NUM> and on to the hose <NUM> and nozzle <NUM>. Control system <NUM> may be any suitable electronics with associated memory and software programs running thereon whether referred to as a processor, microprocessor, controller, microcontroller, or the like. In a preferred embodiment, control system <NUM> may be comparable to the microprocessor-based control systems used in CRIND type units sold by Gilbarco Inc. Control system <NUM> typically controls other aspects of fuel dispenser <NUM>, such as valves, displays, and the like as is well understood. For example, control system <NUM> typically instructs flow control valve <NUM> to open when a fueling transaction is authorized. In addition, control system <NUM> may be in electronic communication with a point-of sale system (site controller) located at the fueling site. The site controller communicates with control system <NUM> to control authorization of fueling transactions and other conventional activities. The memory of control system <NUM> may be any suitable memory or computer-readable medium as long as it is capable of being accessed by the control system.

A vapor barrier <NUM> delimits hydraulics compartment <NUM> of fuel dispenser <NUM>, and control system <NUM> is located in electronics compartment <NUM> above vapor barrier <NUM>. Fluid handling components, such as flow meter <NUM>, are located in hydraulics compartment <NUM>. In this regard, flow meter <NUM> may be any suitable flow meter known to those of skill in the art, including positive displacement, inferential, and Coriolis mass flow meters, among others. Meter <NUM> typically comprises electronics <NUM> that communicates information representative of the flow rate or volume to control system <NUM>. For example, electronics <NUM> may typically include a pulser as known to those skilled in the art. In this manner, control system <NUM> can update the total gallons (or liters) dispensed and the price of the fuel dispensed on information display <NUM>.

As fuel leaves flow meter <NUM> it enters a flow switch <NUM>, which preferably comprises a one-way check valve that prevents rearward flow through fuel dispenser <NUM>. Flow switch <NUM> provides a flow switch communication signal to control system <NUM> when fuel is flowing through flow meter <NUM>. The flow switch communication signal indicates to control system <NUM> that fuel is actually flowing in the fuel delivery path and that subsequent signals from flow meter <NUM> are due to actual fuel flow. Fuel from flow switch <NUM> exits through internal fuel piping <NUM> to fuel hose <NUM> and nozzle <NUM> for delivery to the customer's vehicle.

A blend manifold may also be provided downstream of flow switch <NUM>. The blend manifold receives fuels of varying octane levels from the various USTs and ensures that fuel of the octane level selected by the customer is delivered. In addition, fuel dispenser <NUM> may comprises a vapor recovery system to recover fuel vapors through nozzle <NUM> and hose <NUM> to return to the UST. An example of a vapor recovery assist equipped fuel dispenser is disclosed in <CIT>,.

In accordance with embodiments of the present invention, fuel dispenser <NUM> may be equipped with a plurality of sensors which monitor the health and/or status of various components in the dispenser. For example, one or more sensors may be utilized to provide "open door" fraud detection and prevention, as well as hydraulic component performance and failure monitoring (including indications of impending failure). As an "open door" system, embodiments of the present invention preferably remain functional to mitigate fraud even if panels of the dispenser housing are removed and components of the dispenser have been subjected to physical tampering (such as wires cut). Detection and monitoring may occur remotely, such as via an Internet cloud-based service.

Referring now particularly to <FIG>, certain additional aspects can be explained in greater detail. As shown, a sensor gateway <NUM> in this case communicates with a plurality of sensors located in both the hydraulics compartment <NUM> and the electronics compartment <NUM>. The sensors may be wired sensors (e.g., sensor <NUM>) or wireless sensors (e.g., sensor <NUM>) as necessary or desirable. Preferably, however, sensors located in hydraulics compartment <NUM> may be wireless to reduce the number of wires that need to be passed through vapor barrier <NUM>. For example, a single pickup antenna <NUM> can be passed through vapor barrier <NUM> to communicate with all sensors in the hydraulics compartment. Because, as explained below, MHS <NUM> preferably has several different sensors incorporated into one unit, some or all of the other discrete sensors shown in <FIG> may often be unnecessary.

As noted above, some preferred embodiments of the present invention utilize a MHS <NUM> mounted between filter <NUM> and manifold <NUM>. This single device presents a non-descript profile and provides the ability to communicate securely to control system <NUM>, as well as to remote command and control centers via Internet cloud connectivity. In this regard, sensor gateway <NUM> functionally interposes the various sensors and a cloud connection processor <NUM>. Cloud connection processor <NUM>, in turn, communicates with control system <NUM> and a remote cloud server (either directly or via a router located in the convenience store). Embodiments are also contemplated in which one or more of the sensors are able to communicate securely to the cloud without the need of cloud connection processor <NUM>.

<FIG> illustrates preferred components of sensor gateway <NUM> and cloud connection processor <NUM> in accordance with an embodiment of the present invention. As shown, sensor gateway <NUM> preferably has a microprocessor <NUM> for data relay, housekeeping functions, and optionally some initial processing of sensor data. In this regard, for example, microprocessor <NUM> may comprise a suitable peripheral interface controller (PIC). In this case, sensor gateway <NUM> further includes one or more interface circuits <NUM> for communication with any wired sensors, as well as a radio <NUM> that communicates with the wireless sensors (e.g., MHS <NUM>) via antenna <NUM>.

Cloud connection processor <NUM> preferably has a secure system-on-module (SSOM) <NUM> that provides some processing of sensor data as well as access to control system <NUM> and the cloud server. In this regard, SSOM <NUM> includes a secure processor <NUM>, such as those available from Maxim Integrated of San Jose, California. Secure processor <NUM> contains cryptographic keys to decipher incoming information (from sensors and the cloud), and to encrypt outgoing communications when necessary. Preferably, secure processor <NUM> is tamper resistant such that tampering attempts will cause erasure of the data it contains. Communication between microprocessor <NUM> and secure processor <NUM> may be via serial peripheral interface (SPI). In addition, cloud connection processor <NUM> may include an Ethernet switch <NUM> to handle the incoming and outgoing flow of data. It is expected that, in most embodiments, the cloud server will provide the most powerful processing and analysis of sensor data.

One skilled in the art will appreciate that the use of a gateway device is optional depending on the embodiment. For example, the MHS may be able to communicate to the cloud directly without a gateway to interpret or aggregate for it. Regardless of using a gateway or self-contained model, embodiments are contemplated that use wireless transmission to send out events to the cloud or the gateway or a controlling system. In a system where the MHS communicates directly to the cloud, the cloud may process the data and send control messages from the cloud to the dispenser to stop a transaction or prevent transactions. Embodiments are also contemplated in which the MHS is not cloud-connected, but is connected directly to a controlling device (e.g., control system <NUM>) and the dispenser can send messages to the cloud as a gateway as well as act on the events directly. Various modes of wireless and wired communication are contemplated, including Zigbee, wifi, Bluetooth, RS485, RS422, RS232, CAN, LON, PWM, etc..

Referring now to <FIG> and <FIG>, a preferred embodiment of MHS <NUM> will be explained in more detail. As noted above, MHS <NUM> is configured in this case to fit between the filter manifold and fuel filter. As a result, MHS <NUM> can be easily installed into existing fuel dispensers already deployed, or installed into new dispensers at the time of manufacture. Preferably, MHS <NUM> is equipped with cryptographic keys for communication with sensor gateway <NUM> and cloud connection processor <NUM>. The keys can be injected as MHS <NUM> is put into operation, or when the battery is replaced in the case of embodiments having optional replaceable batteries.

As shown in <FIG>, MHS <NUM> includes a body <NUM> that mounts to a threaded filter mount (post) of manifold <NUM>. Similarly, body <NUM> includes its own filter mount to which filter <NUM> is attached. The interfaces between MHS <NUM> and manifold <NUM>, and between MHS <NUM> and filter <NUM>, replicate the manifold-filter interface. Flow paths are defined in body <NUM> for flow of fuel to and from the filter. Various portions of MHS <NUM> are labeled in <FIG> as follows: (<NUM>) area for MHS controller circuit board and battery; (<NUM>) implementation area for hydraulic sensors and turbine generator; (<NUM>) gasket area; (<NUM>) antenna lens; (<NUM>) antenna circuit board; (<NUM>) threaded interface to manifold; (<NUM>) dismount switch; (<NUM>) embedded vibration sensor; and (<NUM>) embedded acoustic sensor. When MHS <NUM> is fitted to the filter manifold, a locking chemical is preferably utilized to secure it once seated, in order to make removal extremely difficult.

Referring now to <FIG>, an alternative MHS <NUM>' having a body <NUM>' is shown. Body <NUM>' is configured to receive a strainer which is intended to catch large debris (with the filter catching smaller debris). The body <NUM>' has a main portion (labeled "M") in which a plurality of sensors as described above in relation to <FIG> may be located. A strainer fits in the area designated <NUM>. A secondary portion (labeled "S") containing a pressure sensor defines a threaded bore that is attached to the manifold. In particular, when the filter is screwed on, it extends through the secondary portion, through the strainer, and into the main portion. The metal flexes, clamping down to make a seal on the strainer and compress to prevent leaks. This allows a pressure of fluid to be read pre-strainer/pre-filter, and post strainer/post filter to give a full picture of pressure drop through the device.

<FIG> shows a common equipment subsystem contained in MHS <NUM>. As can be seen, this subsystem may include a turbine power generator <NUM> that creates energy during fuel flow. In this embodiment, a replaceable backup battery <NUM> is situated within an intrinsically safe compartment <NUM> defined in body <NUM>, for housekeeping processing when fuel is not flowing. As shown, MHS <NUM> further includes an industrial internet of things (IIoT) microprocessor <NUM> and communications interface for sensor interfacing, housekeeping processing, and cryptographic communications to the cloud connection processor. The communications interface utilizes an RF transceiver <NUM> and built-in antenna <NUM>, or alternatively, a wired interface <NUM>. In embodiments where antenna <NUM> is utilized, a lens <NUM> transparent to the frequencies of antenna <NUM> is preferably located on body <NUM>. Antenna <NUM> may take the form of an inductive loop that radiates primarily a magnetic field, or a monopole/dipole antenna which primarily radiates an electric field. A wired interface can be an intrinsically safe channel with energy limiting components, or passed through a conduit which meets the applicable safety rules, or passed through an encapsulated interface. MHS <NUM> also preferably includes a fuel flow stop valve <NUM> that is actuated as described herein for fraud prevention. A dismount switch <NUM> detects when removal of the MHS from the filter manifold is attempted.

As noted above, turbine power generator <NUM> spins when fuel is flowing to generate energy at a level that preferably corresponds to the maximum power load required for operation of MHS <NUM>. In this regard, flowing fuel rotates a magnet relative to a stationary coil to generate a current flow. This current can be harvested by a rectifier circuit (part of power management circuitry <NUM>) located on the MHS controller circuit board.

The rectifier charges a capacitor <NUM> (e.g., a supercapacitor) to a voltage level related to the speed of rotation. The energy in the capacitor <NUM> could be used to charge the battery used for memory backup, and for system operation. In particular, the capacitor <NUM> may be employed for one or more of the following functions: (<NUM>) To extend battery life by providing start up energy for the time period when fuel begins to flow, before the turbine is up to speed, (<NUM>) Supply energy to operate the fuel flow stop valve, and (<NUM>) Supply energy to provide for sensor operation during battery replacement of in lieu of a battery in some embodiments.

Dismount switch <NUM> is located outside the gasket sealing area (as shown in <FIG>) and is closed once MHS <NUM> is seated. Closing the switch sets an anti-fraud switch flag in the software. If this flag is ever reset via removal of the MHS (thereby opening the switch), a major alarm is generated and transmitted to the gateway.

<FIG> shows an exemplary embodiment of fuel flow stop valve <NUM> in greater detail. Various components of valve <NUM> are labeled in the drawing as follows: (<NUM>) butterfly valve (open); (<NUM>) spring; (<NUM>) low-power solenoid; (<NUM>) plunger moved by the solenoid to lock the valve closed; and (<NUM>) butterfly valve (open). Various anti-fraud events can cause the fuel flow stop valve <NUM> to close. These can include fuel flowing when not authorized by the pump controller, sensing of unauthorized opening of the hydraulic cabinet doors, etc. Furthermore, other sensed conditions can also close this valve, such as excessive debris in the fuel sensed by the ionic sensor (described below).

Preferably, software algorithms may be provided to recognize anomalies that would give false indications of flow issues. For instance, nozzle snaps can cause a tremendous, instant rise and drop of pressure throughout a system (on a dispenser level or site level) as a nozzle is snapped on one dispenser and causes a hydraulic hammer type effect throughout the system. Algorithms can be provided to smooth out these and other false positives of rises and drops in hydraulic performance.

MHS <NUM> preferably includes a suitable pressure sensing arrangement that can detect differential pressure across the filter. Referring now to <FIG>, exemplary embodiments utilize a differential pressure sensor <NUM> inside of body <NUM>. In this case, for example, sensor <NUM> comprises an IC-based micro-electromechanical system (MEMS) differential pressure sensor that is not exposed to the atmosphere. Rather, sensor <NUM> is positioned between two cavities within the MHS, where one cavity is in fluid communication with the fuel filter inlet, and the other in fluid communication with the outlet. In this way the sensor is sensing differential pressure across the fuel filter. Such differential pressure sensing allows detection of one or more of the following: (<NUM>) Filter clogs (DC signal component), (<NUM>) Installation of "cheater filter" (no filtration) or ruptured filter (DC signal component), and/or (<NUM>) Internal meter or valve leaks (AC signal component).

A diagrammatic representation of exemplary fuel temperature sensor <NUM> and ionic sensor <NUM> is provided in <FIG>. As shown, temperature sensor <NUM> is located within the fuel filter outlet cavity to enable real time measurement of fuel temperature for use in automatic temperature compensation (ATC) systems or for other fuel temperature measurement requirements. The sensing element of the ATC probe may be encased in a relatively thin protective housing, such as steel that allows sensing of the fuel temperature with high accuracy. The probe preferably comprises a platinum-based resistance temperature detector (RTD) for highest long term stability, but other suitable sensors can be used. Associated with the ATC is a test well for the authorities to verify the accuracy of the temperature reading system.

Fuel temperature can be used for determining fraud and flow direction of a dispensing system. Fuel at rest will have a normalized temperature rise or drop based on ambient temperature of the device (internal to the dispenser) or ambient temperature on site. Fuel at rest will have a normalized rise in temperature at rest (and the same applies for temperature drop). Moving fluid has a more erratic nature of temperature measurement based on the heating and cooling of the fluid as it moves through the system and mixes and interacts with metal and fluid of differing temperatures. Utilizing an algorithm, gradual rise or drop based on current conditions (both internal and external to the dispenser) can be easily measured to determine what is a "gradual rise or drop" versus erratic rise or drop. This can provide flow and fraud detection potentially without the need for some of the other sensors discussed herein. Temperature in the static state (not flowing) should have a common prediction of heating and cooling where fluid that is flowing will have a fairly variable measurement in temperature due to the turbulent nature of flow.

In this embodiment, ionic sensor <NUM> utilizes a coil pickup around a "pipe" that is internal to the MHS, to sense debris in the fuel filter inlet flow. Ionic level threshold detection can be utilized for setting notification and alarm points for fuel quality.

As shown in <FIG>, MHS <NUM> preferably also includes embedded vibration and acoustic sensors. Preferably, the vibration sensor comprises an acoustic pickup that is directly mounted to the body of the MHS. The acoustic sensor is mounted such that the "microphone" part of the sensor is submerged in the fuel filter inlet cavity. The outputs of the vibration sensor and of the fuel acoustic sensor may be correlated to enable detection of one or more of the following issues: (<NUM>) Meter bearing wear or failure, (<NUM>) Valve bearing wear or failure, (<NUM>) Valve actuator wear or failure, or of associated control signaling faults, (<NUM>) Motor mount wear or failure, (<NUM>) Motor bearing wear or failure, (<NUM>) STP flow problems, (<NUM>) Cabinet door removal, and/or (<NUM>) STP flow problems. Additional information regarding suitable acoustic and vibration sensors, and their operation, can be discerned from <CIT>,.

It can thus be seen that embodiments of the present invention provide novel systems and methods for monitoring the health and/or status of one or more components in a fuel dispensing environment. Notably, embodiments of the present invention may provide advance notice of potential security breaches, component wear or damage, and other operational issues with components in a fuel dispensing environment. Further, embodiments of the present invention provide "behavioral" analysis of a fuel dispenser or fuel dispensing environment, including internal events, customer-originated events, and potential fraud attacks.

Claim 1:
A fuel dispenser (<NUM>) comprising:
fuel flow piping (<NUM>) defining a flow path from a source of fuel toward a fueling nozzle (<NUM>), said fuel flow piping (<NUM>) having a filter manifold (<NUM>) for mounting a fuel filter (<NUM>) thereon, wherein the filter manifold (<NUM>) comprises an inlet filter flow passage and an outlet filter flow passage;
a plurality of fuel handling components disposed along said fuel flow piping (<NUM>);
a sensor device (<NUM>) mounted to the filter manifold (<NUM>) and having a plurality of different sensors operative to detect sensed conditions related to said fuel dispenser (<NUM>),said sensor device (<NUM>) further comprising electronics to transmit signals related to the sensed conditions,
wherein the fuel dispenser (<NUM>) further comprises
a multi-mode hydraulic sensor (MHS), positioned between said filter manifold (<NUM>) and the fuel filter (<NUM>), wherein two cavities are present within said multi-mode hydraulic sensor such that one cavity is in fluid communication with a fluid filter inlet and the other cavity is in fluid communication with a fluid filter outlet.