Abstract: A hybrid combustion mode of an internal combustion engine and a controller thereof, an internal combustion engine, and an automobile.

Abstract: A method of controlling a fuel injector comprises measuring a pressure in a cylinder of an engine with a pressure sensor and determining at least one of a crank angle and a crank speed with a crank sensor. The method also comprises calculating a net indicated mean effective pressure of the cylinder from the measured value of the pressure sensor and the determined value of the crank sensor. Also, the method comprises adjusting a fueling parameter of a fuel injector for the cylinder in response to the difference between the calculated net indicated mean effective pressure and a reference mean effective pressure indicates a change in power of the engine. Alternatively, the method may adjust the fueling parameter based on a power feedback signal for the engine.

Abstract: An engine system includes a combustion chamber including a cylinder, a fuel supply that supplies fuel including gasoline into the combustion chamber, circuitry configured to predict a knock will occur in the combustion chamber, and a fluid injector that injects a fluid into the combustion chamber. Further, there is circuitry configured to suppress a knock by instructing the fluid injector, when the knock is predicted to occur by the circuitry configured to predict, to inject the fluid into the combustion chamber within a period before a burned mass fraction reaches 50% after a start of combustion.

Abstract: A multi-cylinder engine having an engine body with a cylinder head, and mounted on a vehicle is provided. The engine includes first and second cylinder groups each provided to the engine body and comprised of first and second pluralities of cylinders, first and second exhaust passage groups each having first and second pluralities of independent exhaust passage parts provided to the cylinder head and connected to the first and second cylinder groups, respectively, and first and second collective exhaust passage parts provided to the cylinder head and collecting the first and second pluralities of independent passage parts downstream in an exhaust gas flow direction, and a cooling medium passage provided in the cylinder head, through which a cooling medium flows, and having an intermediate passage part provided between the first collective exhaust passage part and the second collective exhaust passage part.

Abstract: There is disclosed a flap for a variable area exhaust nozzle of a gas turbine engine. The flap comprises a support structure and a gas shield connected to the support structure, wherein the support structure is corrugated to accommodate thermal expansion of the gas shield in a direction of corrugation.

Abstract: A flap for a variable area exhaust nozzle of a gas turbine engine. The flap includes a support structure and a gas shield retained thereto. The support structure and the gas shield include a pair of grooves extending in a longitudinal direction of the flap and a pair of corresponding tongues that engage the pair of grooves so as to retain the gas shield to the support structure and to allow movement of the gas shield by thermal expansion along the support structure in the longitudinal direction.

Abstract: A variable section nozzle includes an ejection casing and a plurality of internal flaps arranged in a ring downstream from the ejection casing. Each internal flap is connected to the ejection casing by a movable lever pivotally mounted to the downstream end of the ejection casing. Each lever is movable between a first position in which the internal flaps are in a high position and a second position in which the internal flaps are in a folded-down position. The nozzle includes a plurality of rigid movement transmission parts distributed circumferentially around the ejection casing. Each rigid movement transmission part is connected to two adjacent levers by connecting rods, and to a control actuator. Each rigid movement transmission part can move in a direction corresponding to the axial direction of the nozzle under the action of the control actuator to move the adjacent levers between the first and second positions.

Abstract: The present description provides high working capacity adsorbents with low DBL bleed emission performance properties that allows the design of evaporative fuel emission control systems that are lower cost, simpler and more compact than those possible by prior art. Emission control canister systems comprising the adsorbent material demonstrate a relatively high gasoline working capacity, and low emissions.

Abstract: A multi-cylinder engine includes an engine body having first and second cylinder groups, first and second exhaust passage groups each having a plurality of independent exhaust passage parts and a collective exhaust passage part, and an exhaust gas recirculation (EGR) passage. In a plan view in cylinder axis directions, the passage groups are disposed adjacent to each other, and, in the first exhaust passage group, a first independent exhaust part of the plurality of independent exhaust passage parts is connected to the EGR passage and a second independent exhaust passage part is connected to the collective exhaust passage part so as to be directed to a connection of the first independent exhaust passage part to the collective exhaust passage part, and in the second exhaust passage group, an opening of the collective exhaust passage part is offset toward the first exhaust passage group in a lineup direction.

Abstract: A multi-cylinder engine having an engine body with a cylinder head is provided. The engine includes first and second cylinder groups, each having a plurality of independent exhaust passage parts provided to the cylinder head and connected to cylinders of the first and second cylinder groups, respectively, and first and second collective exhaust passage parts collecting the first and second pluralities of independent exhaust passage parts at a location downstream in an exhaust gas flow direction, and having an opening formed in the side surface part of the cylinder head, first and second exhaust-pipe parts each connected to the openings of the first and second collective exhaust passage parts, respectively, an exhaust gas recirculation (EGR) passage connected at one end to the first exhaust passage group and connected at the other end to an intake passage, and an exhaust gas temperature sensor provided to the first exhaust-pipe part.

Abstract: Methods and systems are provided for an EGR valve diagnostic. In one example, a method may include actuating an EGR valve between first and second positions. The method may further includes determining one or more characteristics of the EGR valve during the diagnostic to determine if an EGR valve cleaning is desired.

Abstract: Methods and systems are provided for adjusting an EGR valve operation based on results from an EGR valve diagnostic. In one example, a method may include executing the EGR valve diagnostic during an engine deactivation, wherein the EGR valve diagnostic estimates an EGR valve stickiness used to adjust the EGR valve operation.

Abstract: Atomic oxygen is provided for the purpose of promoting reliable ignition and smooth combustion in a spark ignition internal combustion engine is to disperse a low concentration of an atomic oxygen precursor, such as nitrous oxide (N2O), into the flammable mixture of air and gasoline vapor prior to the time of ignition. The introduction of N2O may take place in the intake manifold, in the stream of exhaust gas being returned as part of the EGR process, or directly into the combustion chamber (for example through a small orifice in the base of the spark plug or through a small nozzle located elsewhere in the cylinder head). Introduction of N2O directly into the combustion chamber may be continuous, or it may be pulsed so as to occur at the time of, or shortly before, spark ignition.

Abstract: An intake manifold for an internal combustion engine includes a plurality of pieces joined with each other at a linearly extending joint. The pieces include a first piece and a second piece. The joint of the first piece and the second piece includes a first portion and a second portion excluding the first portion. The intake manifold is configured so that the first portion is opposed to a fuel system component of the internal combustion engine when the intake manifold is coupled to the internal combustion engine. A force required to separate the second piece from the first piece is referred to as a joining force. The joining force at the first portion is greater than the joining force at the second portion.

Abstract: A partition plate is configured to separate an intake passage formed by an intake pipe to be coupled to a combustion chamber into a first intake passage and a second intake passage. The first intake passage is openable and closable by a valve. A shape of a first cross section orthogonal to an extending direction of the intake pipe is set on the basis of a shape of a surface of the intake pipe that faces the partition plate with the second intake passage interposed therebetween.

Abstract: An intake system of an internal combustion engine includes an intake pipe through which an intake passage extends, a throttle valve, and a baffle arranged at a downstream side of the throttle valve in the intake passage. The throttle valve includes a shaft, a first valve body configured to close a first region located at a first side, and a second valve body configured to close a second region located at a second side. When the throttle valve opens, the first valve body is pivoted toward an upstream side and the second valve body is pivoted toward a downstream side. The baffle includes a ring, a first net located at the first side of the ring, and a second net located at the second side of the ring. The first net occupies a larger region than the second net.

Abstract: A fuel delivery unit in a fuel tank includes a fuel pump drivable by an electric motor. The fuel pump has at least one suction jet pump for delivering fuel, the suction jet pump being operated by a propulsion jet that is deliverable by the fuel pump. The fuel pump is arranged in a swirl pot, which is fillable by the suction jet pump, and the fuel pump has a first outlet, through which fuel is deliverable to a consumer, and a second outlet openable or closable by a valve.

Abstract: An outboard motor includes an engine, a fuel tank, a fuel pathway, a fuel pump, and a controller. The engine includes a fuel injector. The fuel tank includes an internal space in which fuel is stored. The fuel pathway is connected to the fuel injector and the fuel tank. The fuel pump is disposed in the fuel pathway, and supplies the fuel from the fuel tank to the fuel injector. The controller controls the fuel pump. The controller determines whether or not a start condition, indicating that air has entered the fuel pathway, is satisfied. The controller is configured or programmed to execute an air releasing control to open the fuel injector and drive the fuel pump when the start condition is satisfied.

Abstract: A connection piece for a valve, which is utilized for metering a fluid, includes a sealing section, on which at least one annular sealing element is situated. The annular sealing element circumferentially surrounds the sealing section with respect to a longitudinal axis. Furthermore, the annular sealing element is supported on an end of the sealing section with the aid of a support ring. The sealing section has a circumference increasing along the longitudinal axis at least in an area along the longitudinal axis in which the annular sealing element surrounds the sealing section.

Abstract: An internal combustion engine includes two intake openings, opened and closed by intake valves; exhaust openings opened and closed by exhaust valves; a fuel injector having a plurality of nozzle holes; and mask parts having wall surfaces extending along outer edges of the intake openings toward the inside of the combustion chamber. The fuel injector arranged wherein the nozzle holes are positioned at the opposite exhaust opening sides from the intake openings, and the plurality of nozzle holes include a first nozzle hole, injecting in a direction with the smallest angle from a plane perpendicular to the axial direction of the cylinder. The wall surface formed wherein a height in a first nozzle hole ejection region positioned in a range of injection of a fuel spray from the first nozzle hole, when viewed in the axial direction, is lower than a height in the first nozzle hole ejection region.

Abstract: Various embodiments include an anti-reflection device for preventing the reflection of pressure waves inside an injection valve comprising: a cylindrical base body with a longitudinal axis L to be orientated parallel to a propagation direction of a pressure wave; a first section adjacent to a first base side having a cavity shaped as a hollow cone, a longitudinal axis of the cone orientated parallel to the longitudinal axis L of the device, and a base area of the cone coplanar with the first base side of the cylindrical base body; and a second section adjacent to the second base side comprising a through-hole in fluid communication with the cone, hydraulically linking the second base side with the first base side. The through-hole makes an angle ? with the longitudinal axis L, wherein 40°???60°.

Abstract: When an engine is stopped, a rotational position at a time when a crankshaft starts rotating in a reverse direction is predicted based on a rotational position detected by a crank angle sensor. A target rotational position is set within a range of the crankshaft rotational position between a time when the exhaust valve of one of four cylinders in the expansion stroke when the crankshaft starts rotating in the reverse direction is opened and a time when the expansion stroke of the cylinder ends. When the predicted rotational position is behind the target rotational position, a torque applying device applies a positive rotational torque to the crankshaft. At the time when the exhaust valve of the cylinder in the expansion stroke when the crankshaft starts rotating in the reverse direction is opened, application of the positive rotational torque from the torque applying device to the crankshaft is stopped.

Abstract: The disclosure describes a generator set that includes a generator, an engine mechanically coupled to the generator, an enclosure housing the engine and the generator, a heating system, and a renewable energy-powered energy source. The generator is configured to supply power to an electrical system. The heating system is configured to heat at least one of the engine or the enclosure to at least a startup temperature. The renewable energy-powered energy source is configured to supply energy to the heating system to heat the at least one of the engine or the enclosure.

Abstract: An ignition apparatus for an internal combustion engine includes a spark plug, an ignition coil with a voltage connection, and a spring for electrically connecting the spark plug to the voltage connection. A continuous spring wire in the form of external turns extends from an ignition coil-side end of the spring to a spark plug-side end of the spring. The spring wire at the spark plug-side end continues in the form of internal turns within the external turns in a direction toward the ignition coil-side end.

Abstract: An object of the present invention is to predict change of a combustion limit due to cycle variation of temperature and an EGR ratio and perform correction every cycle to decrease an amount of combustion consumption. Therefore, in an internal combustion engine control device that controls an internal combustion engine including a cylinder and an exhaust pipe, the internal combustion engine control device includes a control unit configured to perform EGR control of controlling an exhaust gas in the exhaust pipe to return to an inner cylinder of the cylinder, obtain temperature of the gas in the internal cylinder and an EGR ratio in a state where both an intake valve and an exhaust valve are closed in an combustion cycle, and correct a combustion parameter in a same combustion cycle as the combustion cycle on the basis of the obtained gas temperature and the obtained EGR ratio.

Abstract: A wave energy converter incorporates a floating body and a reaction body engaging the floating body wherein the reaction body is static or oscillating out of phase relative to the floating body. A power take-off (PTO) has at least one direct drive linear generator, a high level controller responsive to sensors engaged to the direct drive linear generator and providing a PTO force change command (dFPTO) and a low level controller receiving the PTO force change command and providing control signals to power electronics connected to the direct drive linear generator. The direct drive linear generator is operable responsive to the control signals to achieve optimal power extraction performance with high force at low speed with operation in two physical directions and operating as both a motor and a generator for a total of four quadrants of control.

Abstract: Aspects of the present disclosure are generally directed to configurations of power conversion systems for wind turbine generators. For example, certain aspects are directed to a multi-rotor wind turbine. The multi-rotor wind turbine generally includes a plurality of rotors, each coupled to a plurality of electrical generators, one or more machine-side converters, MSCs, coupled to the electrical generators of each of the plurality of rotors and configured to generate at least one direct-current, DC, signal, and one or more line-side converters, LSCs, coupled to the MSCs and configured to generate at least one AC signal based on the at least one DC signal.

Abstract: A vortex generator for a wind turbine blade to be mounted to a wind turbine blade includes: a platform portion to be mounted to a surface of the wind turbine blade; and at least one fin disposed upright on the platform portion. The platform portion has a cross section having a curved convex shape, at least along a blade spanwise direction of the wind turbine blade.

Abstract: A flexible balsa wood panel for a rotor blade of a wind turbine, including a plurality of balsa wood modules and a polymer film which is attached to a surface of each balsa wood module to connect the balsa wood modules together is provided. The flexible balsa wood panel has the following advantages. An adhesion area of the polymer film is significantly larger than that of a glass fiber mesh. This in turn reduces the risk of balsa wood modules falling off during handling the flexible balsa wood panel. A polymer film with a high melting temperature relative to a maximum blade curing temperature can be selected in order to avoid curing process induced delaminations. Furthermore, due to the polymer film attached to the first surface, a more uniform adhesion may be achieved compared to a currently used glass fiber mesh.

Abstract: Wind energy assemblies which contain arrays of wind diodes, which arrays are assembled into a wind energy collector assembly.

Abstract: An actuator device for a wind power installation, in particular for a rotor blade of a wind power installation, and also to an associated wind power installation and a method of assembly, with an actuator component and a control component, wherein the actuator component has at least one actuator layer with a preferential direction and, substantially parallel to the actuator layer, at least one exciting layer, wherein the actuator layer comprises a photoactuator, wherein the photoactuator is designed to change a strain and/or stress of the actuator layer in the preferential direction on the basis of excitation light, wherein the exciting layer is designed to guide excitation light into the actuator layer, wherein the control component comprises a light source and a light guide, wherein the light source is arranged away from the exciting layer and is connected to the exciting layer by means of the light guide. The actuator device makes it possible to ensure greater operational reliability.

Abstract: The present invention provides an electromechanical drive system (1) with at least one electromechanical drive unit (2) to actuate a movable component (3). The electromechanical drive unit (2) comprises a drive unit interface 20 for receiving drive unit control signals (DA), an electromechanical motor (21) controlled by actuation signals (AS) to actuate the component (3), a safety module (4) and a position sensor (5) connected to the safety module via a first data connection (51). The position sensor is adapted to monitor (S1) component (3) and/or motor (21) position and/or speed of the actuated component (3) and/or motor (21); where the safety module (4) is connected to the drive unit interface (20) for receiving the drive unit control signal (DA), and where the safety module is connected to the motor control unit (22) via a third data connection (41) to transmit actuation signals (AS) like actuation speed and desired component position to the motor control unit (22) for actuating (A) the component (3).

Abstract: A method for controlling a wind turbine based on aerodynamic performance maps that account for blade twist includes controlling the wind turbine based on at least one aerodynamic performance map. Further, the method includes determining at least one speed parameter of the wind turbine. Moreover, the method includes determining a blade torsional stiffness factor. Thus, the method further includes determining, via the processor, a twist correction factor for the aerodynamic performance map as a function of the at least one speed parameter and the blade torsional stiffness factor. The method then includes applying the twist correction factor to the at least one aerodynamic performance map to obtain an adjusted aerodynamic performance map. In addition, the method includes controlling the wind turbine based on the adjusted aerodynamic performance map.

Abstract: A wind turbine is provided. The turbine includes a support having an axis of rotation, a generator, a plurality of blades rotatably mounted on the support about the axis of rotation, the blades being moveable between a retracted position generally parallel with the axis of rotation and a fully deployed position generally perpendicular with the axis of rotation, the blades being connected to the generator such that rotation of the blades in a direction induced by wind causes the generator to produce electricity, and the provision of electricity to the generator rotates the blades, and a controller connected to the generator and configured to deliver a flow of current to the generator that is sufficient to move the blades from the retracted position toward the fully deployed position and insufficient to move the blades all the way to the fully deployed position.

Abstract: Provided is a method for transmitting controlling control variables from a windfarm controller to units including at least one wind power installation at least one energy store. The method include determining first and second controlling control variable components by the windfarm controller, outputting the first controlling control variable component in a first data packet, outputting the second controlling control variable component in a second data packet, receiving the first and second data packets by a first unit, and determining a controlling control variable from the first and second controlling control variable components. The first data packet has a receiver address which is assigned to the first unit and to at least one further unit, and the second data packet has a receiver address which is assigned to at least the first unit. Provided is a windfarm controller, a wind power installation and a windfarm configured to perform the method.

Abstract: A method, computer program product, and wind power plant are disclosed for controlling power production of the wind power plant comprising a plurality of wind turbine generators. The method comprises defining, based on received wind information, a wind wake zone comprising one or more first wind turbine generators of the plurality of wind turbine generators. The method further comprises increasing a reactive power production of at least one of the one or more first wind turbine generators of the wind wake zone.

Abstract: A power generation sailing ship has a sail provided on a deck, a water turbine connected to a front end of a shaft passing through a bow part outer hull and extending forward, a power generator disposed in a front body of the sailing ship and connected to a rear end of the shaft, and an energy storage device for directly storing electric energy generated by the power generator or converting the electric energy into energy of a substance and storing the substance.

Abstract: A system and method for evaluating loads of a potential wind farm site for multiple wind scenarios includes (a) receiving, via a computer server, site data of the potential wind farm site representing at least one wind scenario for at least one wind turbine at the potential wind farm site. Further, the method includes (b) selecting, via a user interface, a wind farm configuration based on the at least one wind scenario. The method also includes (c) selecting, via the user interface, a time period for the at least one wind scenario. Thus, the method includes (d) automatically generating, via the computer server, a mechanical loads analysis for the selected wind farm configuration and the time period.

Abstract: The invention relates to a method for pitch angle measurement and/or for constructing a pitch angle measurement system on a rotor blade (100) of a wind turbine, the rotor blade comprising a blade root (114) and extending along a longitudinal blade axis (180). The rotor blade is rotatably mounted, by its blade root (114), to rotate about the longitudinal blade axis (180), on a rotor hub (20) of the wind turbine, the rotor hub rotating or being rotatable about a rotor axis (36). At least one chord line direction indicator (430) is firmly connected to the rotor blade (100) at a distance from the blade root (114), and defines a chord line direction indicator direction (160) indicative of a direction of a chord line (140) of the rotor blade (100) at the location of the chord line direction indicator (430).

Abstract: A leading edge of a wind-turbine blade has a carefully designed predetermined shape. After operation of the blade, erosion damages that shape and the blade needs repair. Repair is difficult to carry out in the field or, for offshore turbines, at sea. A shroud (8) for repairing a damaged leading edge of a wind-turbine blade (2) is rigid and has a shape matching the predetermined shape of the leading edge. Advantageously the shroud has a multi-layered structure in which a base layer (10) of the shroud comprises a rigid material.

Abstract: A fixture and methods of using the fixture that can be used in situ to perform repair and maintenance work on a generator shaft and associated components of a wind turbine generator is described. The fixture is typically mounted to a plurality of the threaded bores provided in the generator housing used to attach the generator's end bell or the gearbox/transmission to the generator, and provides a platform for attaching accessory fixtures to support the shaft of the generator, as well as, provide for the mounting of tools used to maintain and repair the generator shaft.

Abstract: The invention provides a method for opening a cover portion (202) of a wind turbine (1) comprising a nacelle (2) mounted on top of a tower (4), the nacelle supporting a rotor (3) and a generator (104) connected to the rotor, the nacelle (2) comprising a cover (201) presenting an access opening (203), the cover portion (202) being adapted to removably cover the access opening (203), the nacelle (2) also comprising a service crane (204), a cooler (205) being mounted to the nacelle (2) on an exterior of the nacelle (2), the method comprising attaching (S1) at least one hinge tool (6) to the cover portion (202) and to the cover (201), the hinge tool (6) presenting a swing joint (603), opening (S5) by means of the service crane (204) the cover portion (202) in a pivoting motion around the swing joint (603), and securing (S6) the opened cover portion (202) to the cooler (205).

Abstract: A cooling system includes one or more heat generating components located within an enclosure. A first conduit is thermally connected to one or more of the heat generating components, and the first conduit is fluidly connected to a distribution manifold and a condensing unit. The condensing unit is located external to the enclosure and above the heat generating components. The distribuition manifold is located below the heat generating components. A second conduit is fluidly connected to the condensing unit and the distribution manifold. The cooling system includes a two-phase cooling medium. The first conduit, condensing unit, second conduit and distribution manifold form a loop in which the cooling medium circulates.

Abstract: A combined cycle power plant comprises a combustion turbine generator, another heat source in addition to the combustion turbine generator, a steam power system, and an energy storage system. Heat from the heat source, from the energy storage system, or from the heat source and the energy storage system is used to generate steam in the steam power system. Heat from the combustion turbine generator exhaust gas may be used primarily for single phase heating of water or steam in the steam power system. Alternatively, heat from the combustion turbine generator exhaust gas may be used in parallel with the energy storage system and/or the other heat source to generate steam, and additionally to super heat steam. Both the combustion turbine generator and the steam power system may generate electricity.

Abstract: An osmotic power generator comprising an active membrane supported in a housing, at least a first chamber portion disposed on a first side of the active membrane for receiving a first electrolyte liquid and a second chamber portion disposed on a second side of the active membrane for receiving a second electrolyte liquid, a generator circuit comprising at least a first electrode electrically coupled to said first chamber, and at least a second electrode electrically coupled to said second chamber, the first and second electrodes configured to be connected together through a generator load receiving electrical power generated by a difference in potential and an ionic current between the first and second electrodes.

Abstract: A hydraulic device includes a shaft mounted in a housing rotatable about a first axis of rotation. The shaft has a flange extending perpendicularly to the first axis. A plurality of pistons is fixed to the flange. A plurality of cylindrical sleeves cooperates with the pistons to form respective compression chambers of variable volume. The cylindrical sleeves are rotatable about a second axis of rotation which intersects the first axis of rotation by an acute angle such that upon rotating the shaft the volumes of the compression chambers change. Each piston has a piston head including a circumferential wall of which the outer side is ball-shaped and the inner side surrounds a cavity. Each of the pistons is fixed to the flange by a piston pin having a piston pin head including a circumferential outer side facing the inner side of the circumferential wall of the piston head.

Abstract: The present invention relates generally to pumps, and more particularly to a system of pumps wherein a first hydraulic motor operatively connected to a first master pump can hydraulically drive a second hydraulic motor operatively connected to a second slave pump. More particularly, a hydraulic fluid outlet of the first hydraulic motor is fluidically connected to a hydraulic fluid inlet of the second hydraulic motor whereby the first hydraulic motor, operatively connected to the first pump, drives the second hydraulic motor, operatively connected to the second pump, in a hydraulically synchronized manner.

Abstract: A linear compressor of the present invention comprises: a shell having a suction portion; a cylinder disposed in the shell and forming a compression space for a refrigerant; a piston arranged to axially reciprocate in the cylinder; and a spring device for inducing a resonant motion of the piston, wherein the spring device comprises a spring, a first supporter to which one side of the spring is connected and which moves together with the piston, and a second supporter to which the other side of the spring is connected, and each of the supporters has a coupling groove for fitting the spring therein.

Abstract: Provided is a variable-capacity compressor control valve that is compact and is capable of suppressing the influence of the pressure difference between the crank chamber pressure Pc, the suction pressure Ps, and the like. A valve body includes an in-valve release passage for releasing a pressure Pc in a crank chamber to a suction chamber of a compressor via a Ps inlet/outlet port. A sub valve element adapted to open or close the in-valve release passage along with movement of the plunger is provided.

Abstract: Described is an air compressor which can be fixed to the wall, comprising a plate which can be fixed to a wall, a supporting and containing body hinged on the plate so as to oscillate about a respective predetermined axis of oscillation, an electrically powered air compression unit housed in the supporting and containing body, a reel for winding a flexible hose for passage of the compressed air from the compression unit.