Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M51/00—Fuel-injection apparatus characterised by being operated electrically
  • F02M51/06—Injectors peculiar thereto with means directly operating the valve needle
  • F02M51/061—Injectors peculiar thereto with means directly operating the valve needle using electromagnetic operating means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M69/00—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel
  • F02M69/04—Injectors peculiar thereto
  • F02M69/041—Injectors peculiar thereto having vibrating means for atomizing the fuel, e.g. with sonic or ultrasonic vibrations
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M69/00—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel
  • F02M69/04—Injectors peculiar thereto
  • F02M69/042—Positioning of injectors with respect to engine, e.g. in the air intake conduit
  • F02M69/043—Positioning of injectors with respect to engine, e.g. in the air intake conduit for injecting into the intake conduit upstream of an air throttle valve

Definitions

• the present invention relates to a fluid mixing device, of the type apt to inject a first fluid, coming at a first pressure from a supply source, in a gaseous state comprising a second fluid, in order to obtain a mixture of both fluids.
• Endothermic reciprocating engines with spark ignition are fed obtaining an air-fuel mixture upstream the combustion chamber.
• This air-fuel mixture is usually obtained taking the fuel from a tank by means of a suitable electro-pump and conveying it to an electric injector.
• Said electric injector will injects the fuel nebulizing it inside the intake duct, wherein the air flows. Through the intake duct the air-fuel mixture is then conveyed to the combustion chamber.
• Said injection method is called Single Point Injection (SPI); another injection method, i.e. the Multi Point Injection (MPI) is also known, which provides for an electric injector in each one of the cylinders, located near the cylinder inlet.
• SPI Single Point Injection
• MPI Multi Point Injection
• SPI and MPI injection methods employ electric injectors with electromagnetic control, consisting of a needle sliding inside a body whereto the fuel flows.
• the needle is provided at its end with a shutter, whose movement allows or prevents the fuel to flow out under pressure from an exit nozzle.
• the control is electromagnetic, so that the needle is provided on its middle with a magnetic keeper, while inside the injector body a suitable coil is located for magnetic control of the needle, according to the known pattern of a solenoid valve.
• injectors which, instead of the electromagnetic control, employ piezoelectric means for opening the electric valve.
• Common injectors being located sideways of the intake duct, do not allow an optimal mixing of the fuel with the air flowing in the duct. Moreover, said injectors often produce a nebulization of the fuel in drops, which is not sufficient for an optimal combustion. In fact, if the size of the fuel drop injected in the air is greater than a determined value, it may happen that a portion of the drop is not burnt, so impairing the engine efficiency. Such injectors also show a high inertia typical of the electromechanical systems, so that the injecting frequency is limited to a few hundreds of Hz, resulting in a not so flexible injection control.
• injectors work with an injection pressure of a few bars, so that the fuel is always under pressure, with evident risks in case of breakage of the fuel conveying ducts, for instance due to an accident, so requiring the additional presence of inertial breakers in the fuel feeding circuit.
• a further object of the present invention is to provide a fluid mixing device and/or a method for the mixing of fluids, which allow for obtaining a homogeneous mixing of the first fluid in the second fluid.
• a further object of the present invention is to provide a fluid mixing device and/or a method for the mixing of fluids, which allow for the use of fuel substantially at low pressure.
• a further object of the present invention is to provide a fluid mixing device and/or a method for the mixing of fluids, which allow for controlling and changing the amount/flowrate of the first fluid in the second fluid.
• FIG. 1 shows the basic schematic diagram of a fuel injection system for internal combustion engines, according to the present invention
• Fig. 2 shows the basic schematic diagram of a mixer device in the form of a fuel injector for internal combustion engines, according to the present invention
• FIG. 3 shows the perspective diagram of a detail of the fuel injection device according to Fig. 1;
• Fig. 4 shows the basic schematic diagram of a detail of the fuel injection device according to Fig. 1.
• Fig. 1 is illustrated a schematic diagram of a fuel injection system 1 according to the invention, realized according to the teaching of the present invention.
• an intake duct 2 conveying the air required for the combustion mixture from the air inlets, not shown here, of the motor vehicle.
• the intake duct 2 has an air filter 3, and downstream the filter is located a butterfly body 4, comprising a butterfly valve 5. Downstream the butterfly body 4 there is located an air "plenum" 6, from which departs a plurality of intake ducts 7 ending in a cylinder head, not shown.
• a fuel tank 9 is also provided, from which an hydraulic fuel conveying circuit 10 is departing, indicated by a thicker line.
• This hydraulic fuel conveying circuit 10 is operated by means of a fuel pump 11 ; downstream the pump there is located a fuel filter 12. The arrangement of these elements is also commonly known.
• the hydraulic fuel conveying circuit 10 Downstream the fuel filter 12, the hydraulic fuel conveying circuit 10 comprises a dosing device 13. Inside the intake duct 2 there is located a mixing device or injector 14. Said injector device has a housing 15 with streamlined shape, which is hold up by proper supports 19, so that the housing 15 is axially arranged in respect of the intake duct 2. On the circumference of the housing 15 there are provided a number of slots 20. The hydraulic fuel conveying circuit 10 continues beyond the dosing device 13 to reach inside of the housing 15 thanks to one of the supports 19, which is appropriately hollow and has the shape of a pipe.
• an electronic control unit 16 which is also known in itself, and is provided with electrical connections 17 to the injector device 14 located inside the intake duct 2. Through an electrical connection 18, the electronic control unit 16, in turn, receives a signal about the position of the butterfly valve 5.
• FIG. 2 there is shown the basic schematic diagram of a mixing device or injection device 14 according to the present invention. It should be noticed how in this figure the sizes of the various components of the invention, as further described, are magnified with respect to the housing 15, so as to obtain a clearer representation of them.
• the injection device 14 as said, consists of the housing 15, having a typical streamlined shape, the function of which is to delimit, together with the walls of the intake duct 2, a number of conduits having a profile of a Venturi tube. It should be noticed that one of the supports 19 continues inside of the profile and connects to an axial duct 22, which ideally ends the hydraulic fuel conveying circuit 10.
• the axial duct 22 also acts as a support for four mixer 23.
• Each mixer 23 substantially comprises: a dosing disk 24, made of ferromagnetic material, with a central hole for its keying or fastening on the duct 22; a disk counterplate 28, provided on its perimeter with a raised rim 29, in sealed cooperation with the disk 24; also the counterplate 28 has a central hole for its keying or fastening on the duct 22.
• Each raised rim 29 of the counterplate 28 and the surface of the dosing disk 24 are sealed overlapped, so that between the dosing disk 24 and counterplate 28 a substantially cylindrical chamber 30 is delimited; to this purpose, at least the edge 29 will be made of a suitable material apt to warrant the required hermetical sealing.
• the axial duct 22 has a number of holes 31 in line with every chamber 30, in order to let it be filled with the fuel coming from the feeding circuit 10, through the support 19.
• Reference 26 indicates a supporting element with a set of electromagnets 26A on its surface facing the dosing disk 24, which form a round crown as a whole. Said electromagnets 26A are driven and energized by the control unit 16 so as to locally draw the dosing disk 24. Thus, the dosing disk 24 is locally distorted, so as to delimit an outlet orifice for the fuel contained in the chamber 30.
• control unit 16 may be programmed for the sequential driving of the electromagnets 26A.
• a travelling wave is in fact obtained, which runs the circumference of the dosing ring 24; in other words, the sequential drive of the electromagnets 26A will cause the above local distortion of the dosing disk 24 "to run" along the perimeter of the disk.
• the system may comprise a plurality of chambers 30.
• each supporting element 26 may have crowns of electromagnets 26A on both its faces; thus, each supporting element 26 can drive two different dosing chambers 30.
• the counterplate 28 can advantageously lay between two dosing disks 24; in this case, both opposite surfaces of the counterplate 28 will be provided with a raised edge 29, capable of sealing cooperation with a respective dosing disk 24.
• the injection device 14 operates as follows: the fuel is conveyed through the fuel pump 11 in the fuel conveying duct 10.
• the dosing device 13 is used to feed the mixing device or injector 14 and supply the fuel amount required plus a slight overpressure due to the hydrostatic pressure of the fuel contained in the section of the fuel conveying circuit 10, comprised between the dosing device 13 and the axial duct 22.
• the mixer 23 due to the effect of the travelling distorsion of the dosing disk 24, generates a spill, which moves along the circumference.
• the combined effect of the overpressure inside the fuel conveying circuit 10 and pressure drop due to the housing 15 has the effect of micronizing the fuel drops 35 of the spill and move them quickly away from the raised rim 29, so improving their mixing with the air.
• the electronic control unit 16 receives the information about the position of the butterfly valve 5 through the connection 18, so that it can conveniently control the sequential feed frequency of the electromagnets 26A, and consequently the rotation speed of the travelling wave or distortions in the injector device 14.
• the electronic control unit 16 has moreover the possibility of modulating the feed voltages of the electromagnets 26A, changing the amplitude of the distortion or travelling wave and, consequently, the local distance between the dosing disk 24 and the counterplate 28, (or better the edge 29 of the latter), and therefore the size of the injected drop.
• Each mixer comprises therefore a first element, the dosing disk 24, a second element, the counterplate 28, and a third element, the support 26 of the electromagnets 26A, where the first and second elements delimit the chamber 30.
• the action of the electromagnets 26A creates a local controlled spacing (a few ⁇ m) of the dosing disk 24 from the counterplate 28; this spacing delimits a nozzle 34 where through the fuel spills into the intake duct 2, under the action of the slight pressure established inside the chamber 30.
• the effect of the distortion or travelling wave is therefore so, that such nozzle or orifice 34 is moving with a substantially circumferential motion along the dosing disk perimeter 24, delimiting an injection point that is moving in the time, apt to make the injection more even and control it by means of the frequency and amplitude of the voltage signals.
• the dosing device 13 which receives in input the hydraulic fuel conveying circuit 10 and delivers in output, through an outlet duct 38, the fuel to the mixer device 14.
• a float 39 Inside the dosing device 13 there is located a float 39, provided on the top with a pin shutter 40.
• the fuel pushed by the fuel pump 11 enters the dosing device 13 and flows through the outlet duct 38 to the mixer device 14.
• the pin shutter 40 on the float 39 closes the fuel conveying circuit 10
• fuel feeding will stop.
• the fuel feeds the mixer device 14 by gravity, until the fuel level decreases and the pin shutter 40 will open again the fuel conveying circuit 10.
• the dosing device 13 can be removed, sizing the fuel conveying circuit 10 in the way that it is a closed circuit, namely by means of a return line to the tank, so assuring a constant fuel pressure in the chamber 30.
• the same effect can be achieved by pressing the dosing disk 24 on the counterplate 28 with a tightening force being compatible with the described system operation.
• the mixer device 14, shown in Fig. 2 is provided with four mixers 23, which are fastened and kept in place by suitable tightening nuts 32 and/or spacers 33.
• the number of mixers 23 located in the axial duct 22 may also be greater, and such a number will be calculated as a function of the flowrate requested by the specific application.
• the number of electromagnets 26A forming each crown arranged on the support 26 will be calculated as a function of the size of the drops or micro amounts of fluid to be obtained.
• the control unit 16 can control the mixers 23 in a different way. For instance, assuming that three mixers 23 are provided, they can be driven by means of signals shifted in phase by 120° to each other, so that the corresponding distortions or travelling waves in the relevant three chambers 30 will be consequently delayed in phase and generate an even distribution of the injected fuel, avoiding any interference. From the above description the features of the present invention as well as the relevant advantages thereof are clear.
• the fluid mixing device in particular a fuel injector for internal combustion engines, advantageously allows for nebulizing a first fluid (fuel) directly inside the conveying duct of a second fluid (air - comburent), favoring micronization and mixing, so improving the ratio managing capability between both fluids and in conclusion their consumption/performance ratio for the application in internal combustion engines.
• the first fluid or fuel is distributed along the whole circumference of the mixer or injector, so improving both the injection uniformity and mixture quality.
• the fuel mixing device described above advantageously allows for an easy and efficient dosing of the first fluid, also controlling both the rotation frequency of the distortion or travelling wave, through the frequency of the voltage signals generating it, and the size of the injected drops through the amplitude of such signals.
• the device according to the invention allows to operate with a low pressure in the intake circuit of the first fluid or fuel, to the injector device.
• the pressure needed at the fuel pump is about 1 bar, so that a simple cheap membrane pump can be used, directly driven by the engine, or in the case of a favorable layout of the hydraulic circuit, a pump may even be dispensed of, taking advantage of the hydrostatic pressure.
• the use of a low pressure involves clear advantages in the design of the hydraulic feeding circuit of the first fluid or fuel.
• control unit 16 may be programmed for obtaining a non sequential energization of the electromagnets 26A of each crown, but simultaneously, i.e. based on an activation logic of the electromagnets of pulsing type.
• this will no longer produce a localized distortion in just one peripheral point of the dosing disk 24, but a distortion of the whole disk, so as to obtain the maximum flowrate obtainable by the mixing system, said distortion of the whole disk 24 being obtained by the set of single local distortions generated by each electromagnet 26A.
• both energizing systems (sequential and simultaneous or pulsing) do not exclude each other, but they create a further flexibility element for controlling the system.
• the supporting component 26 of the electromagnets 26A does not necessarily have a ring shape. It is also clear that appropriate driving of the electromagnets 26A may bring to a simultaneous production of several distortions or traveling waves 34 on one same dosing disk, which will determine several orifices at the same time. It shall be possible, taking advantage of a greater number of mixer 23 according to the invention, namely more chambers 30 available, to associate a different fluid to each mixer device; in the case of engines using more than one type of fuel, one of the mixer may inject oil. One or more mixer 23 may also be assigned for gas or fuel additives injection. On the other hand, the mixer 23 shall also inject other materials that can be absorbed by fluids or gas, such as finely ground powders, e.g. powdered coal.
• the invention is also applicable for the mixing and/or injection of all fluids compatible with the size of the hydraulic circuit. It is also clear that the ability of injecting or mixing a wide range of fluids makes the device according to the invention apt to different uses other than described in the case of an internal combustion engine, wherever a precise dosing of micro amounts of fluid is required. Possible applications are for instance their use as dosing devices in chemical, pharmaceutical or heating plants, etc.
• the injector device can also be used in association not only with the intake duct of an engine, but additionally as an alternative to, or in connection with the air conveying ducts to the cylinders, in analogy with MPI technique.
• the latter may bear only one set of through electromagnets, the ends of which would extend out towards two different dosing disks 24, each end being polarized and energized appropriately, according to procedures clear for the man skilled in the art.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Fuel-Injection Apparatus (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

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ID=11458037

Family Applications (1)

Country Status (4)

Citations (6)

• 2000
  • 2000-09-14 IT IT2000TO000865A patent/IT1320642B1/it active
• 2001
  • 2001-09-14 EP EP01965515A patent/EP1322860A1/en not_active Withdrawn
  • 2001-09-14 AU AU2001286152A patent/AU2001286152A1/en not_active Abandoned
  • 2001-09-14 WO PCT/IB2001/001681 patent/WO2002025103A1/en not_active Application Discontinuation

Patent Citations (6)

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