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
  • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
  • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
  • F02M61/18—Injection nozzles, e.g. having valve seats; Details of valve member seated ends, not otherwise provided for
• • 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
  • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
  • F02M61/04—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00 having valves, e.g. having a plurality of valves in series
  • F02M61/06—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00 having valves, e.g. having a plurality of valves in series the valves being furnished at seated ends with pintle or plug shaped extensions
• • 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
  • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
  • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
  • F02M61/162—Means to impart a whirling motion to fuel upstream or near discharging orifices
  • F02M61/163—Means being injection-valves with helically or spirally shaped grooves
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B1/00—Engines characterised by fuel-air mixture compression
  • F02B1/12—Engines characterised by fuel-air mixture compression with compression ignition

Definitions

• the present invention relates to a fuel injection nozzle primarily for internal combustion engines.
• liquid fuel In the majority of internal combustion engines liquid fuel is used which is injected in the air in the inlet manifold as in typical spark ignition (SI) engines or more or less compressed air in the cylinder as in direct injection (Dl) homogeneous and stratified charge (SI) engines or compression ignition engines i.e. Diesel and homogeneous charge compression ignition (HCCI) engines. Rapid fuel atomization, evaporation and fuel-air mixing must be achieved in the engines for proper operation and low emissions. Therefore a leading issue in engine development is improving fuel atomization.
• SI spark ignition
• DI direct injection
• SI homogeneous and stratified charge
• HCCI homogeneous charge compression ignition
• Orifice injectors with multiple small and ultra-small, circular and non-circular injection orifices, swirl injectors, pintle injectors, liquid-liquid and liquid-surface impingement injectors, vibratory injectors, air assisted injectors, heated tip injectors, and many others have been developed for the SI engines, as discussed extensively in the SAE Technical Paper No. 950506 by Fu Quan Zhao et al., "The Spray Characteristics of Automotive Fuel Injection - A Critical Review", 1995.
• For compression injection engines currently almost exclusively multiple, small diameter injection orifices are used.
• Another object of the present invention is to provide a high performance multishot injector simple in construction and capable of being easily manufactured and assembled.
• Yet another object of the present invention is to provide a multishot injector which does not require multiple opening of the needle valve per cylinder firing.
• a still further object of the invention is to provide an injector minimizing emissions, especially of nitrogen oxides and particulate matter (soot) by modification of the injection process.
• Another object of the present invention is to provide an injector which at lower injection pressures and for larger injector orifices generates fuel sprays of quality satisfying the demands of contemporary internal combustion engines.
• a still further object of the invention is to provide an injector which in spite of increased nozzle sizes prevents engine wall wetting by the fuel leading to larger unbumed hydrocarbon and soot emissions.
• an interruption means preferably in the form of a ball
• a swirl flow of fuel is generated.
• the ball moves around in the sac, sequentially covering the injection orifices and thus generating multishot injections in rapid sequence from each of them.
• the injections are regular and can be synchronized with the air swirl in the combustion chamber to secure uniform fuel distribution in the combustion air.
• the invention provides a simple, yet overwhelmingly effective solution to a long standing problem particularly in the art of compression ignition (Diesel) engines.
• Diesel compression ignition
• the same technology could also be applied to other injection systems of internal combustion engines in particular direct injection SI engines and HCCI engines as well as in liquid atomization devices used in other application fields.
• FIG. 1 is a schematic perspective view of a fuel injection nozzle according to the present invention
• FIG. 2 is a schematic cross-sectional view of the lower end of the fuel injection nozzle illustrated in Fig. 1, with the left-hand side of the drawing illustrating the nozzle in a closed condition and the right-hand side of the drawing illustrating the nozzle in an open condition;
• FIG. 3 is a schematic cross-sectional view of the nozzle sac of the fuel injection nozzle according to the present invention on a relatively large scale
• FIG. 4 is a sectional view along line IV-IV of Fig. 3.
• reference numeral 10 denotes a fuel injection nozzle in accordance with the present invention.
• the fuel injection nozzle comprises a nozzle body 12 having a guide passage 14 extending along a longitudinal axis L.
• the guide passage has a first end 16 connectable to a (not shown) fuel source and a second end 18.
• the nozzle body 12 further comprises a nozzle sac 20 having a plurality of orifices 22, of which two are shown in the drawings.
• the nozzle sac 20 communicates with the second end of 18 of the guide passage 14.
• the fuel injection nozzle 10 also comprises valve means 24 for opening and closing in a conventional manner the second end 18 of passage to thereby control fuel flow to the nozzle sac 20.
• valve means 24 for opening and closing in a conventional manner the second end 18 of passage to thereby control fuel flow to the nozzle sac 20.
• the valve means is a needle valve having a tip 26.
• the needle valve is provided with a frusto-conical end portion 28 adjacent to the tip 26.
• the frusto-conical end portion 28 of the needle valve is adapted to rest against a frusto-conical valve seat 30 in the nozzle body 12 when the valve is in its closed position.
• the needle valve is lifted such that the frusto-conical end portion 28 leaves the valve seat 30 to thereby place the guide passage 14 in liquid communication with the nozzle sac 20. Accordingly, the needle valve controls the opening and closing of the injection nozzle 10 i.e. the injection timing and duration.
• the nozzle sac 20 of the fuel injection nozzle 10 accommodates interruption means 32 operable by the fuel flow to sequentially open and close the plurality of orifices 22.
• interruption means 32 operable by the fuel flow to sequentially open and close the plurality of orifices 22.
• the expression “sequentially open and close the plurality of orifices” it is meant that the fuel flow effects displacement of the interruption means such that an orifice which has been closed and thereafter opened by the interruption means will not be closed again until another orifice has been closed.
• Such opening and closing of the orifices takes place during the open phase of the valve means 24.Thus, the term “sequentially” does not necessarily imply that all of the orifices are opened and closed one after the other in a completely preset order, even though this is obviously preferable.
• the interruption means 32 may be easily influenced, and hence, operable by the fuel flow
• the interruption means is a freely displaceable member, preferably a ball having a diameter d.
• the freely displaceable member must be made from a material of higher density than the fuel.
• the guide passage 14 may be provided with means, such as a groove, for generating swirl in the fuel flow as the fuel enters the nozzle sac.
• the valve means 24 may be provided with means, such as a groove 34, for generating swirl in the fuel flow as the fuel enters the nozzle sac.
• the groove 34 is inclined at an angle ⁇ relative to the longitudinal axis L of the fuel injection nozzle.
• the groove or grooves 34 act as a swirl passage for the fuel.
• the combination of the swirl flow imposed by the grooves 34 and straight flow imposed by the passage 14 provides flexibility to obtain a global fuel swirl of desired intensity below the needle when the injection nozzle is opened and fuel injection occurs.
• the fuel swirl is enhanced due to conservation of angular momentum when the fuel moves along the frusto-conical valve seat 30 (vortices rotate faster when their diameter decreases) and enters the sac.
• fuel rotation in a wide range of rotational speeds can be realized easily in the sac. Also other ways of inducing fuel swirl in the sac are possible even if they may be more complicated.
• the interruption means 32 is forced by the fuel flow to move around the nozzle sac 20 causing sequential opening and closing of the injection orifices 22, thus producing a number of sequential injections from each of them i.e. realizing the required multishot operation. It is not necessarily essential that the orifices be uniformly distributed around the nozzle sac. Nevertheless, in one embodiment of the present invention, the plurality of orifices 22 are uniformly distributed around the nozzle sac and are at least five in number, preferably between five and ten in number.
• the multiple injections provide substantially improved fuel atomization, air entrainment into the fuel spray and better air utilization in the engine, increasing power density, combustion and cycle efficiency and reducing emissions.
• the nozzle sac 20 comprises a track, generally denoted by 36, along which the plurality of orifices 22 is arranged.
• the track 36 presents a guide surface 38 for the interruption means 32.
• the guide surface 38 delimits an internal diameter D of the nozzle sac and the nozzle sac comprises a substantially planar bottom surface 40 bordered by the guide surface 38.
• the base of the sac has internal radii close as possible to, though slightly larger than, the radius of the interruption means, in the shown example in the form of a ball.
• the location of the inlets to the orifices 22 are advantageously arranged in the middle of the contact of the ball with the guide surface 38.
• the frequency of injections is controlled by the fuel swirl in the sac and/or by the fuel flow turbulence.
• the frequency shall be synchronized with the air swirl in such a way that the sequential injections occur when the air has moved around the combustion chamber 12-15 deg. Then the fuel is always injected in fresh air and not in the oxygen depleted wake of the previous injection leading to substantial combustion improvements. This would require the fuel swirl number in the sac to be typically about four times larger than the swirl number of the air in the combustion chamber.
• the ratio of injection interval to the injection time in a single shot depends on the ball to sac diameter ratio d/D. Good combustion results are obtained for the interval duration of about 0.3 of the single shot duration which can be achieved for d/D of about 0.75-0.8. Smaller balls provide shorter intervals which are also beneficial. Thus typically the preferred d/D value is in the range of from 0.5 to 0.9, preferably from 0.6 to 0.8, and most preferably about 0.75 to 0.8. Larger balls cause a decrease of the overall discharge rate of the injector which, if necessary, can be restored by increasing the diameters of the injection orifices.
• the discharge rate is reduced about 30 % which can be compensated by increase of the injection orifice diameters by 14 %.
• the ball also reduces the volume of fuel in the sac and thus in the same proportions reduces the unburned hydrocarbons (UHC) emissions of the engine.
• UHC unburned hydrocarbons
• the present invention has been described in connection with an intermittent fuel injection nozzle for an internal combustion engine.
• the principle of operation i.e. using interruption means operable by a liquid flow to thereby effect multishot injections, may be applied to any liquid atomization nozzle for any application, in particular using continuous flow.
• any liquid atomization nozzle for any application, in particular using continuous flow.
• using the nozzle described above, with a continuously open needle will provide continuous multishot operation providing improved atomization and fuel air mixing.
• liquid nozzle having a cylindrical chamber with liquid being admitted to the chamber through a plurality of spaced-apart, inclined slots, and an interruption means having a cylindrical shape, for example in the form of a roller, passing over the slots sequentially, improved liquid atomization can be attained in a continuous flow nozzle.
• Such nozzles could have applications in gas turbine engines, stationary power plants and burners. Similar arrangements are conceivable In agricultural watering equipment.

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

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• 2002
  • 2002-12-06 SE SE0203625A patent/SE0203625D0/xx unknown
• 2003
  • 2003-12-05 WO PCT/SE2003/001873 patent/WO2004053326A1/en not_active Ceased
  • 2003-12-05 EP EP03781188A patent/EP1576282A1/de not_active Withdrawn
  • 2003-12-05 AU AU2003287121A patent/AU2003287121A1/en not_active Abandoned

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