Abstract: A piezoelectric power generator assembly includes a housing, a piezoelectric transducer located in the housing, and a piston located in the housing. The piston is movable with respect to the housing and is configured to be moved into contact with the piezoelectric transducer, and the piezoelectric transducer is configured to generate an electrical charge when contacted by the piston.

Abstract: A vibrational multi-morph piezoelectric energy harvester includes a composite shim having a parallelepiped form with a thickness dimension made smaller than width and length dimensions, and having a stiffness shifting from one extremity to the other extremity to minimize mechanical constraints developed at a clamping area; a seismic mass mounted at an end opposite to the clamping area to mechanically match the system to the surrounding vibration resonance; one or more piezoelectric layers laminated on said composite shim; and electrodes plated onto the one or more piezoelectric layers for connection to an electronic harvesting circuit, a battery, or a super capacitor.

Abstract: A piezoelectric energy harvester has a box, a plurality of first arc-shaped metal stands and a plurality of arc-shaped piezoelectric elements. The box has an upper portion, a connection base, a buffer element and a lower portion. The connection base situates between the upper portion and the lower portion. The upper portion movably connects with the lower portion through the buffer element. The plurality of first arc-shaped metal stands situated on a side of the connection base in the box. Each of the arc-shaped piezoelectric elements locates on each of the first arc-shaped metal stands. When an external force applied on the box, the plurality of first arc-shaped metal stands deforms due to the compression from the upper portion and consequently causes the deformation of the arc-shaped piezoelectric elements for generating electricity accordingly.

Abstract: Provided is a device for measuring a signal and a method of operating the same. The device may include electrodes attached to the device, and a control unit for determining the optimal pair of electrodes to be used for measuring the signal. Also, the device may include an output unit for measuring signals that are sensed by the electrodes.

Abstract: A piezoelectric energy harvester is provided. The piezoelectric energy harvester includes a housing, a metal plate, a first piezoelectric material, an auto-returning device, a movable supporter, a first magnet and a second magnet. The housing includes a bottom plate, a top plate, a first side wall and a second side wall. A first terminal of the metal plate is fixed on the first side wall and a second terminal of the metal plate extends toward the second side wall. The first piezoelectric material is disposed on the metal plate to be deformed when the metal plate is deformed. When the movable supporter is moved, the movable supporter can push the second terminal of the metal plate to deform the metal plate. The first magnet and the second magnet are respectively disposed on the bottom plate and the top plate to attract the second terminal of the metal plate.

Abstract: A power generation device for a mobile body includes power generating units and a holding member. Each power generating unit includes an elastically deformable base member and a piezoelectric film, which are laminated alternately. The holding member holds the power generating units. Each power generating unit has an elongated flat-plate shape. Opposite ends of the power generating unit in a longitudinal direction are held by the holding member such that the power generating unit is in an orientation in which a longitudinal axis is substantially perpendicular to the flow direction of the external fluid. A fixing member is provided at each of the opposite ends in the longitudinal direction of each power generating unit. The power generating units are arranged in the holding member via the fixing members to pivot in accordance with the flow of the external fluid.

Abstract: A method and apparatus for waking a battery pack from a dormant mode via shaking. The battery pack has a piezo electric device coupled to a semiconductor control circuit providing a power path between a positive terminal of a battery cell and a boot input of an ASIC charge/discharge controller powered by the battery cell. Shaking of the piezo electric device energizes the semiconductor control circuit, which engages the power path to power the initial booting of the ASIC charge/discharge controller.

Abstract: A system and method for harvesting energy from a vehicle, e.g., an aircraft, in operation. A plurality of piezoelectric members are coupled between structural members in the vehicle. A first portion of the plurality of piezoelectric members are non-resonant piezoelectric spacers coupled between structural members subject to a constant load during operation of the vehicle. A second portion of the plurality of piezoelectric members are resonant piezoelectric fillers coupled between structural members subject to a cyclical load during operation of the vehicle. Electrical conversion circuitry is coupled to each of the plurality of piezoelectric members for converting the output of each piezoelectric member to usable electrical energy. The electrical conversion circuitry is coupled to an energy storage device for storing the usable electrical energy and/or to an interface circuit for supplying energy for use in an electrical system in the vehicle.

Abstract: A vibration power generation device including a multiple-degree-of-freedom vibration system comprising a first vibration system and a second vibration system, wherein a natural frequency of the first vibration system is different from a natural frequency of the second vibration system. A first mass member of the first vibration system has a hollow structure including a housing space inside, where the second vibration system is housed. A power generating element is mounted on a plate spring of the second vibration system. A support part projects within the housing space, and one end side of the plate spring is attached to the support part and supported within the housing space at a position inward from a peripheral wall of the first mass member. A second mass member of the second vibration system is attached to another end side of the plate spring.

Abstract: A hairdryer including an ionizing system and a heater wherein the ionizing system comprises an ion producing electrode and the ion producing electrode extends along an external periphery of the heater. The ion producing electrode may extend along the heater to a downstream end of the heater. The ion producing electrode may extend along the heater from an upstream end of the heater. The heater may be generally cylindrical and the ion producing electrode extends along a radially outer surface of the heater. The ion producing electrode may have a first part which extends along a first axis and the first part extends along the external periphery of the heater. The ion producing electrode may have a second part, which extends along a second axis, wherein the second part extends radially inwards from the external periphery of the heater.

Abstract: A piezoelectric quartz shear-mode resonator includes plasma etched quartz tethers, each including a mount. The tethers are for mounting the resonator to a semiconductor substrate for the purpose of isolating the thermally-induced stress from the mounts from the active resonating region, wherein the quartz tethers have rounded corners.

Abstract: Methods and apparatus are provided for a vehicle electronic power system. In one exemplary embodiment an energy harvesting device is configured to generate electricity in response to vibration of the vehicle occurring during normal vehicle operation. The energy harvesting device may be tuned to a frequency that falls within a peak energy region in a vibration profile of the vehicle. The power system may further include a charging circuit connecting the energy harvesting device to a rechargeable battery provides electrical power to an electro-mechanical vehicle component or system.

Abstract: A power harvesting switch circuit includes a main switch and a voltage extractor connected in series between Line wire and switch wire. The main switch includes a first power MOSFET and a second power MOSFET connected in series. The voltage extractor includes a first Zener diode and a second Zener diode connected in series but in opposite directions.

Abstract: An acoustic biometric touch scanner device and method is disclosed. In one aspect, an acoustic fingerprint sensing device includes an array of ultrasonic transducers configured to transmit an ultrasound signal having a frequency in a range from 50 megahertz (MHz) to 500 MHz. The acoustic fingerprint ultrasonic transducers include a piezoelectric film. The acoustic fingerprint sensing device further includes a receiving surface configured to receive a finger. The acoustic fingerprint sensing device further includes a processor configured to generate an image of at least a portion of a fingerprint of the finger based on a reflection of the ultrasound signal from the finger.

Abstract: A wireless charging method includes obtaining charging information of a plurality of electronic devices, and charging the plurality of electronic devices in sequence according to the charging information of the plurality of electronic devices. For each electronic device, a charging resonance frequency is chosen and accordingly the corresponding wireless charging power is provided for charging.

Abstract: Disclosed is an electromechanical generator for converting mechanical vibrational energy into electrical energy, the electromechanical generator comprising: a mass resiliently connected to a body by a biasing device and adapted to oscillate about an equilibrium point relative to the body with an oscillation amplitude, a transducer configured to convert oscillations of the mass about the equilibrium point relative to the body into electrical energy, and a resilient device disposed between the biasing device and one of the mass and the body, wherein the resilient device is configured to be deformed between the biasing device and the one of the mass and the body only when the oscillation amplitude exceeds a predetermined non-zero threshold amplitude. The resilient device may comprise one of a helical spring, an O-ring and a spring washer, such as a Belleville washer, a curved disc spring, a wave washer, and a split washer.

Abstract: A piezoelectric energy harvesting apparatus includes a housing and a piezoelectric module disposed in the housing. The piezoelectric module includes a piezoelectric wafer unit and a clamp unit clamping the piezoelectric wafer unit. A resilient member is connected between the clamp unit and an inner wall of the housing to transmit an oscillation movement to the clamp unit, which in turn causes oscillation of the piezoelectric wafer unit for generating an electric power. An impact unit extends movably into the housing and is capable of pushing the clamp unit against the resilient member when being subjected to an ambient natural force such that the resilient member generates the oscillation movement.

Abstract: A piezoelectric power generation apparatus that includes a first vibrating portion having a fixed end and a free end, a first weight portion bonded to the free end of the first vibrating portion, a second vibrating portion having a fixed end bonded to the first weight portion and a free end, and including a vibrating plate and a piezoelectric element provided on the vibrating plate. A second weight portion is bonded to the free end of the second weight portion. In a state where the piezoelectric power generation apparatus is arranged on a vibration surface and is still, a position of the free end of the first vibrating portion and a position of the fixed end of the second vibrating portion in an axial direction perpendicular to the vibration surface are different from each other.

Abstract: Devices, methods, systems, and computer-readable media for a two-way radio harvester and transmitter are described herein. One or more embodiments include a two-way radio harvester and transmitter comprising a rectifier connected between a receive element and a storage element to harvest and convert a signal into direct current (DC) power and store the DC power, a gate coupled to the storage element and a controller to allow the DC power in the storage element to power the controller when the gate reaches a power threshold and closes, and a transmitter connected between the controller and a transmit element to convert data containing information about preselected items by the controller into radio frequency (RF) signals to be transmitted by the transmit element.

Abstract: Provided are an energy harvester using a mass, and a mobile device including the energy harvester. The energy harvester includes: a mass; first and second substrates spaced apart from each other, wherein one of the first and second substrates is connected to the mass; first and second electrodes provided on the first and second substrates; and an energy generator provided between the first and second electrodes, wherein the energy generator generates electric energy upon a relative movement between the first substrate and the second substrate caused by a movement of the mass.

Abstract: A piezoelectric power generation device includes a stator, a rotor, and one or more piezoelectric power generation elements. The stator comprises an internal surface which defines an internal orifice. The one or more piezoelectric power generation elements are disposed on the internal surface of the stator. The rotor is disposed within the internal orifice comprising one or more lobes formed on an outside surface of the rotor. The rotor is configured to rotate with respect to the stator and the one or more piezoelectric power generation elements. The one or more lobes contact the one or more piezoelectric power generation elements as the one or more lobes rotate past the one or more piezoelectric power generation elements. The one or more piezoelectric power generation elements generate energy when contacted by the one or more lobes.

Abstract: Embodiments of the invention provide a piezoelectric vibration module, including a vibration plate mounted with a piezoelectric element, which generates a vibration force in a vertical direction by being repeatedly expanded and contracted depending on external power applied thereto, and a lower case coupled with both ends of the vibration plate so as to be spaced apart from the vibration plate. The piezoelectric vibration module further includes a bar-shaped weight body increasing the vibration force of the piezoelectric element, and an elastic member interposed between the vibration plate and the weight body.

Abstract: An embodiment provides a band, including: an energy harvesting mechanism that stores energy in response to deformation of the band; a device; and a connection coupling the stored energy of the band to the device. In an embodiment, a force is applied to deform a deformable band along a length dimension of the deformable band. The force acts to move an energy harvesting mechanism of the deformable band such that the energy harvesting mechanism transforms deformation of the deformable band into stored energy. The stored energy may be used, e.g., to collect information using a sensor of said deformable band. Other aspects are described and claimed.

Abstract: An energy generating device and a method of manufacturing the same are provided. The energy generating device includes a first electrode, a metal layer, including a regular arrangement of a plurality of patterns, disposed on the first electrode, an organic material layer positioned on the metal layer, and a piezoelectric layer interposed between the first electrode and the organic material layer.

Abstract: A circuit for use with a contactor including at least one contact is provided. The circuit includes a first segment including a voltage source, a first coil, a second coil, and a first transistor, wherein the first segment is configured to selectively conduct a closing current through the first coil, the second coil, and the first transistor to close the at least one contact. The circuit further includes a second segment including the first coil, a second transistor, and a first diode, wherein the second segment is configured to selectively conduct a holding current through the first coil, the second transistor, and the first diode to hold the at least one contact closed, and wherein the first diode is arranged such that substantially all current produced by the voltage source flows through the first coil.

Abstract: According to one embodiment, a remote control device for a toilet device includes an operation button and a power generator. The operation button is capable of a push operation and is configured to operate an equipment in response to the push operation. The power generator is configured to generate a power by being pressed in response to the push operation. A direction of the pressing is parallel to a wall surface on which the remote control device is placed.

Abstract: A number of devices are described which can be used to generate electric power from the action of wind or other sources of vibration. The devices comprise Piezo electric materials, which are built into the devices in a way that can capture the generated electric power, and can conduct it to storage devices. Several embodiments are described.

Abstract: A vibrational energy harvesting system is disclosed. Included is a first energy harvesting unit and a second energy harvesting unit that convert mechanical vibrations into first and second AC signals, respectively. A first AC-DC converter coupled to the first energy harvesting unit and a second AC-DC converter coupled to the second energy harvesting unit are configured to convert the first AC signal and the second AC signal into a first DC signal and a second DC signal, respectively. A DC-DC converter is coupled between the second AC-DC converter and a controller, and is configured to receive the second DC signal and provide a regulated DC signal by using energy from the second DC signal in response to a periodic signal generated by the controller. Typically, an energy storage unit is coupled to the DC-DC converter and is configured to receive and store energy from the regulated DC signal.

Abstract: Example embodiments relate to optoelectronic devices. An optoelectronic device may include a photoactive layer between first and second electrodes, and a ferroelectric layer corresponding to at least one of the first and second electrodes. At least one of the first and second electrodes may include graphene. The photoactive layer may include a two-dimensional (2D) semiconductor. The optoelectronic device may further include a third electrode, and in this case, the ferroelectric layer may be between the second electrode and the third electrode. The second electrode, the ferroelectric layer, and the third electrode may constitute a nanogenerator.

Abstract: The invention is directed to a piezovoltaic energy harvesting laminate that includes a photovoltaic laminar wafer comprised of a plurality of photovoltaic cells and a dielectric wafer that converts mechanical energy to electrical energy. A boundary laminate interface is disposed between the photovoltaic laminar wafer and the dielectric wafer. The boundary laminate contains a metallization layer electrical terminal for the photovoltaic cells and a conduction layer of the dielectric wafer.

Abstract: An ultrasonic transducer having a membrane and a container having a base and at least one wall element. The one or more wall elements can be situated over at least part of the base to form a cavity that can have an at least partially open end. The open end can be sealed with the membrane and the interior of the container can be maintained at a lower atmospheric pressure than the ambient pressure. Within the container, a piezoelectric flexure can be fixed at one end to a location at a wall element. The other end of the flexure can be in mechanical communication with the membrane, either directly or through a stiffener that is itself in communication with the membrane.

Abstract: A pickup sensor is disclosed for a magnetostrictive sensing instrument for sensing position of a magnetic field. The instrument includes an elongate tube having a near end and a distal end. A magnetostrictive wire in the tube has first and second ends. The second end is operatively secured at the tube distal end. The pickup sensor comprises a housing mounted proximate the tube near end. A pair of crystals are in the housing sandwiching the magnetostrictive wire so that interaction between an electric pulse on the magnetostrictive wire and a magnetic field produces a torsional wave on the magnetostrictive wire sensed by the pair of crystals. A pair of spring elements are mounted in the housing sandwiching the crystals to provide consistent contact force between the crystals and the magnetostrictive wire.

Abstract: The present disclosure generally relates to electrical power generation from a piezoelectric material. A piezoelectric power generator assembly is disclosed including a housing, a piezoelectric transducer located in the housing, and a piston located in the housing, wherein the piezoelectric transducer is configured to generate an electrical charge when contacted by the piston. A piezoelectric power generator assembly is also disclosed including a housing comprising a flowline located within the housing and a piezoelectric transducer located in the housing and disposed about a perimeter of the flowline, wherein the piezoelectric transducer is configured to generate an electrical charge when contacted by a fluid contained in the flowline. A subsea drilling system is disclosed including a subsea blowout preventer stack and a piezoelectric power generator assembly for powering sensors on the blowout preventer stack configured to monitor characteristics of the stack.

Abstract: A piezoelectric material that does not use lead and potassium and has a high piezoelectric constant and good insulating properties and a piezoelectric element that uses the piezoelectric material are provided. The piezoelectric material contains a perovskite-type metal oxide represented by general formula (1): (NaxBa1-y)(NbyTi1-y)O3 (1) (where 0.80?x?0.95 and 0.85?y?0.95), and an auxiliary component containing at least one selected from the group consisting of Si and B. A content of the auxiliary component on a metal basis is 0.001 parts by weight or more and 4.000 parts by weight or less relative to 100 parts by weight of the perovskite-type metal oxide.

Abstract: Disclosed are various embodiments of systems, devices and methods for generating electricity, transforming voltages and generating motion using one or more piezoelectric elements operably coupled to one or more non-piezoelectric resonating elements. In one embodiment, a non-piezoelectric resonating element is configured to oscillate and dissipate mechanical energy into a piezoelectric element, which converts a portion of such mechanical energy into electricity and therefore acts as a generator. In another embodiment, a piezoelectric element is configured to drive one or more mechanical elements operably coupled to the one or more non-piezoelectric resonating elements, and therefore acts as a motor. In still another embodiment, a piezoelectric element is operably coupled to a non-piezoelectric resonating element to form an electrical transformer.

Abstract: The present disclosure includes: a magnetostrictive plate including a magnetostrictive material; a yoke around which a coil is wound and which has two ends magnetically connected to a surface of the magnetostrictive plate; and a bias magnet that generates bias magnetic flux circulating from one of the two ends of the yoke to the other one of the two ends through the yoke. Here, the magnetostrictive plate is surface-bonded to a non-magnetic structural body.

Abstract: A self-power synchronized switch harvesting on inductor circuit for harvesting energy from a piezoelectric element generating an AC voltage, comprises an envelope detector having first and second capacitors connected in parallel with the piezoelectric element and functioning as negative and positive voltage detectors. An inductor is connected in parallel with the capacitors, and transistors are connected in circuit with the capacitors and inductor and are responsive to a change in voltage across the first capacitor from positive to negative to enable flow of positive voltage to the inductor until terminal voltage reaches a certain amount and current in the inductor reaches zero. A full-wave rectifier is connected to convert the AC output of the piezoelectric element to DC voltage, and a DC-DC converter is connected to adapt the power output of the rectified voltage.

Abstract: The energy harvester module of the capsule comprises: a primary oscillating structure subjected to an external low-frequency stress; a secondary oscillating structure comprising an elastic element and able to vibrate in high-frequency resonance; and an electrostatic structure with a first electrode coupled to the primary structure and a second electrode coupled to the secondary structure. The electrodes exert a mutual attraction between them driving the secondary structure away from its stable equilibrium position with tensioning of the elastic element, up to a limit beyond which the secondary structure is released by relaxation effect to vibrate at a resonance frequency. A transducer coupled to the secondary structure converts these high frequency vibration movements into electrical energy.

Abstract: The present invention relates to an energy harvester device, which includes an elongate, planar resonator beam comprising a piezoelectric material and side walls extending between first and second ends; a base connected to the resonator beam at the first end with the second end being freely extending from the base as a cantilever; and a mass attached to the second end of the resonator beam. The side walls are continuously curved within the plane of the resonator beam. Also disclosed are a system containing the device, and methods of using and making the device.

Abstract: The present invention relates to an energy harvester device comprising an elongate resonator beam comprising a piezoelectric material, the resonator beam extending between first and second ends; a base connected to the resonator beam at the first end with the second end being freely extending from the base as a cantilever; a mass attached to the second end of the resonator beam; a package surrounding at least a portion of the second end of the resonator beam; and a stopper connected to the mass and/or the second end of the resonator beam, where the stopper is configured to prevent contact between the second end of the resonator beam and the package. Also disclosed is a system, a method of powering an electrically powered apparatus, and methods of producing an anergy harvester device.

Abstract: A piezoelectric generator for power supply of a portable terminal is provided. The piezoelectric generator includes: a portable terminal case which has a battery mounting part formed on one surface thereof and has parts of the portable terminal mounted therein; a slide part which is formed on opposite side surfaces of a border of the portable terminal case to be able to slide up and down; and a piezoelectric body which has one end or opposite ends connected with the slide part and is disposed in the battery mounting part in a transverse direction, and which vibrates by a sliding movement of the slide part.

Abstract: An energy harvesting device harvests energy from an energy source, and includes an inductor and a control switch coupled in series, and a control module. The series connection of the inductor and the control switch is adapted to be coupled to the energy source in parallel or in series. The control module is coupled to the control switch, and controls operation of the control switch between an ON state and an OFF state such that the control switch starts to operate in the ON state for a predetermined time period from a transition time point during each predetermined cycle starting from a start time point, and such that a time difference between the transition time point and the start time point is variable.

Abstract: Disclosed herein are techniques and systems for providing simulated, haptic feedback that is local to physical, non-actuating keys of a keyboard. A keyboard includes a plurality of non-actuating keys defined in a cover portion of the keyboard, a plurality of force-producing mechanisms coupled to a substrate underneath and adjacent the cover portion. The force-producing mechanisms may be positioned on suspended portions of the substrate that are mechanically isolated and arranged on the substrate to substantially correspond to a layout of the plurality of non-actuating keys. The force-producing mechanisms may be individually actuated to deflect the suspended portions of the substrate underneath the cover portion to create a tactile sensation for a user's finger that is local to a particular key. In some embodiments, the force-producing mechanisms are piezoelectric actuators.

Abstract: A device for converting heat energy into electrical energy including cells, the cells including: a first cavity with one wall for contacting a heat source; a second cavity with one wall for contacting a cold source; a primary channel between the first cavity and the second cavity transporting a fluid as liquid drops, the primary channel providing transport of liquid fluid drops from the second cavity to the first cavity; at least one secondary channel between the first cavity and the second cavity transporting the fluid as a gas; a piezoelectric material provided in one of the cavities; and a fluid as a liquid and gas contained within the cell.

Abstract: An energy harvesting device has been developed for low frequency applications. The energy harvesting device is comprised of a buckling member having a longitudinal axis and configured to exhibit multiple snap-through events in response to a deformation applied axially thereto, where the buckling member is constrained laterally in relation to the longitudinal axis; and at least one cantilever extends outwardly from the buckling member. The cantilever(s) is coated with a piezoelectric material and supports a mass disposed at an opposing end from which it is attached to the buckling member. In this arrangement, the buckling member is able to respond to axial deformations occurring at a frequency less than one Hertz.

Abstract: The present invention relates to a gas combustor, which includes a casing unit of the gas combustor and a detachable ignition module, the detachable ignition module is to have an igniter being modularized as a single unit, thereby being enabled to be inserted in or removed from an insertion slot preformed on a surface of the casing unit of the gas combustor, and a cathode connecting joint and a anode connecting joint of the detachable ignition module are respectively in contact with or separated from an electric conductive wire installed in the insertion slot, thereby establishing or terminating an electric connection, so the inconvenience and possible danger of replacing the igniter by the user himself is avoided.

Abstract: Energy harvesting systems and devices are provided that harvest energy from external asynchronous force impulses using fluidic force transfer of the external force impulses to a plurality of compliant piezoelectric layers that seal a corresponding plurality of inner cavities. Each inner cavity can contain a compressible gas. Direct fluidic force transfer can be accomplished via a compressible or incompressible fluid between an external cover and the compliant piezoelectric layers.

Abstract: Systems and methods for constructing a stator for use in downhole equipment such as ESP systems, where granulated filler material is used instead of encapsulants to provide mechanical support to the stator windings, provide electrical insulation in the stator slots, and conduct heat away from the windings. In one embodiment, a stator for an electric motor includes a plurality of laminations stacked together to form a stator core. Stator windings are positioned in slots within the stator core. The stator core and windings are installed in a stator housing, and a solid, granular filler material is used to fill an unoccupied volume within the slots. Retainer fittings are secured to the stator to retain the granulated filler material in the slots.

Abstract: A piezoelectric material that does not use lead and potassium and has a high piezoelectric constant and good insulating properties and a piezoelectric element that uses the piezoelectric material are provided. The piezoelectric material contains a perovskite-type metal oxide represented by general formula (1): (NaxBa1-y)(NbyTi1-y)O3 (1) (where 0.80?x?0.95 and 0.85?y?0.95), and an auxiliary component containing at least one selected from the group consisting of Si and B. A content of the auxiliary component on a metal basis is 0.001 parts by weight or more and 4.000 parts by weight or less relative to 100 parts by weight of the perovskite-type metal oxide.

Abstract: An irrigation apparatus is provided, comprising: a pressure vessel configured to hold water under pressure, and configured to expand and contract based on the pressure of the held water; a selectable throttle configured to receive water at a first pressure, configured to provide the water to the pressure vessel at the first pressure when the selectable throttle is at a first setting, and configured to provide the water to the pressure vessel at a second pressure that is smaller than the first pressure when the selectable throttle is at a second setting; a control circuit configured to control whether the selectable throttle is at the first setting or at the second setting; and a piezoelectric element attached to the pressure vessel and configured to generate electricity when the pressure vessel expands or contracts.