US3797756A - Electromagnetically actuated fuel injection valve for internal combustion engines - Google Patents

Electromagnetically actuated fuel injection valve for internal combustion engines Download PDF

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US3797756A
US3797756A US00338305A US3797756DA US3797756A US 3797756 A US3797756 A US 3797756A US 00338305 A US00338305 A US 00338305A US 3797756D A US3797756D A US 3797756DA US 3797756 A US3797756 A US 3797756A
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Prior art keywords
valve
valve needle
fuel
bore
armature
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US00338305A
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English (en)
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W Voit
K Ziesche
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Robert Bosch GmbH
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Robert Bosch GmbH
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    • 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
    • F02M51/0625—Injectors peculiar thereto with means directly operating the valve needle using electromagnetic operating means characterised by arrangement of mobile armatures
    • F02M51/0664—Injectors peculiar thereto with means directly operating the valve needle using electromagnetic operating means characterised by arrangement of mobile armatures having a cylindrically or partly cylindrically shaped armature, e.g. entering the winding; having a plate-shaped or undulated armature entering the winding
    • F02M51/0685—Injectors peculiar thereto with means directly operating the valve needle using electromagnetic operating means characterised by arrangement of mobile armatures having a cylindrically or partly cylindrically shaped armature, e.g. entering the winding; having a plate-shaped or undulated armature entering the winding the armature and the valve being allowed to move relatively to each other or not being attached to each other
    • 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

Definitions

  • ABSTRACT An electromagnetically actuated fuel injection valve for internal combustion engines, the valve needle of which, guided in a bore of the valve housing, is connected to the armature of an electromagnet and is lifted from a valve seat when the electromagnet is energized, against the force of a return spring and against the direction of flow of the fuel which is fed under pressure from an external pressure source, thereby establishing communication between a pressure chamber adjacent the valve seat and a discharge nozzle outlet is described, wherein the valve needle is coupled to a compensating piston which is guided coaxially with the valve needle and the armature, in a fluid tight manner in the said bore.
  • the compensating piston has a first frontal face which is pressurerelieved and a second frontal face which is exposed to the fuel pressure, and a cross sectional area which is so large that, when the injection valve is closed, the hydraulic forces acting on the valve needle in the dileast approximately equal.
  • This invention relates to an electromagnetically actuated fuel injection valve for internal combustion en-' gines, the valve needle of which is guided in a valve housing and is connected with the armature of an electromagnet; upon energization of the electromagnet, this valve needle is lifted from its valve seat against the force of a return spring and against the direction of flow of fuel which is supplied with a predetermined fuel pressure from a fuel pump or the like pressure source,
  • a further drawback of these valves resides in the fact that the opening and closing times of the valve depend on the fuel pressure; for, at a constant magnet energizing time, the opening movement of the valve needle is more or less delayed, or its closing movement more or less accelerated, depending on the level of the fuel pressure, whereby the amount of injected fuel is subject to variations.
  • This object is attained by a coupling of the valve needle with a compensating piston which is guided coaxially with the valve needle and with the armature in a guiding bore of the valve housing, a first frontal face of this piston is pressure-relieved, while its other frontal face is exposed to the fuel pressure, and its cross sectional area is so large that, in the closed injection valve, the hydraulic force acting upon the valve needle in the direction of opening is equal or at least approximately equal to the acting thereon in the direction of closing the valve.
  • the sole connection between a pressure chamber adjacent the valve needle and a fuel feeding chamber which faces toward the armature and is limited by the second frontal face of the compensating piston is established by a fuel passage having a throttle means therein.
  • the throttle means inserted in the fuel passage causes a pressure drop in the fuel which counteracts the additional hydraulic force which would occur without the provision of the throttle, and which would increase the hydraulic force acting in the opening direction when the valve is open.
  • a complete or near complete compensation of this additional force can be achieved by providing a throttle means having a throttling cross sectional area reducing the pressure in the pressure chamber sufficiently to make the force acting in the pressure chamber on the valve needle in the direction of opening, when the injection valve is open, approximately equal to the force acting in the same chamber in the same direction when the valve is closed, whereby a dynamic balance of forces is achieved besides the static balance mentioned earlier.
  • the cross sectional area corresponding to the guiding diameter of the guided portion of the valve needle in the bore of the housing is at least ten times as large as the cross sectional area of flow through the valve seat, for, if this is the case, then the pressure drop produced by the throttle means will amount to maximally one tenth of the fuel pressure.
  • a preferred embodiment of the invention provides for a coupling of the compensating piston to the valve needle via an elastically bendable connecting member, thereby extending the valve needle-and-armature unit, and for a diameter of the compensating piston which is equal to, or at least approximately equal to the diameter of the valve seat.
  • the adjustment of the fuel injection valve is facilitated by having a fuel supply duct extend essentially within and along the longitudinal axis of the valve needle, and by providing an exchangeable screw member which is inserted in an enlargement of the duct and which contains the throttle means, and by having a guiding bore for the piston disposed in an exchangeable guiding sleeve which is firmly mounted in a duct of the valve housing leading to a return fuel line.
  • the compensating piston is arranged intermediate the valve needle and the armature, and is connected with the armature and coupled to the valve needle for force transmission via a rigid connecting member; and the cross sectional area corresponding to the diameter of the compensating piston is smaller, by the cross sectional area corresponding to the diameter of the valve seat, than the cross sectional area corresponding to the guiding diameter of the valve needle, whereby only forces resulting from fuel pressure are effective between the compensating piston and the valve needle, thus increasing the safety of the operation.
  • a static and dynamic balancing of forces can also be achieved in yet another advantageous embodiment of the valve according to the invention by guiding the valve needle, downstream of the valve seat, in a fluidtight manner by means of a guiding plug in a bore provided in the end face of the valve housing facing toward the combustion space, and by having the compensating piston serve as a connecting member between the armature of the electromagnet and the valve needle, the
  • the guiding plug has the shape of a plug nozzle tip and is provided with a cavity; this cavity is closed toward the end of the valve needle remote from the valve seat and has the nozzle aperture opening into the combustion space, in a manner known per se, as well as at least one connecting bore leading to an annular channel provided in the mantle surface of the guiding plug and controlled by the valve seat.
  • valve needle is provided with a guiding piston upstream of the valve seat and a spraying plug located downstream of the valve seat and penetrating into the nozzle aperture; and the compensating piston serves as a connecting member between the armature of the electromagnet and the valve needle, the piston diameter being at least approximately equal to the diameter of the valve seat; in a particularly preferred embodiment of this valve, a narrow annular gap is formed between the spray plug and the nozzle aperture which gap is laid out only for the passage of a partial amount of the fuel quantity to be injected for operation under full load, and the spray plug has at least one additional spray bore, controllable after a preliminary stroke, to permit passage of the total quantity of fuel to be injected under full load, or for a quantity of fuel to be injected under partial load which latter quantity is larger than the quantity of fuel injectable through the annular gap, whereby there will prevail the most favorable injection conditions for any partial amount of fuel to be injected as well as for the injection of the quantity required for full load operation.
  • FIG. 1 is a partly schematical sectional view of a first embodiment of the injection valve, in closed position
  • FIG. 2 is a sectional view similar to that of FIG. 1, of the same injection valve in open position;
  • FIG. 3 is a sectional view of a second embodiment of the valve according to the invention.
  • FIG. 3a is an enlarged partial sectional view taken from FIG. 3, in the region of the valve seat;
  • FIG. 4 is a sectional view of a particularly illustrative portion of a third embodiment, taken in the region of the valve needle;
  • FIG. 5 is a sectional view of a particularly illustrative portion of a fourth embodiment, taken in the region of the valve needle and the compensating piston;
  • FIG. 6 is a sectional view of a similar region as shown in FIG. 5, but of a fifth embodiment.
  • FIG. 7 is a sectional view similar to that of FIG. 6, but of a sixth embodiment of the valve according to the invention. I 7
  • the first embodiment of an electromagnetically actuated fuel injection valve 10 comprises a valve housing 9 which has been shown schematically as an integral piece, and a valve needle 12 which is guided in a housing bore 11 by means of a guiding portion 13 thereof, the guiding diameter of which has been designated by D (FIG. 2).
  • the valve needle 12 is stepped and bears at the downstream end of its reduced diameter portion 17 a valve cone 14 which is seated on a valve seat 15 and thereby obturates the flow of fuel to the nozzle apertures 16, when the fuel injection valve is in closed position (FIG. 1).
  • Pressure source 19 as well as the structural elements pertaining thereto are well known per se and are therefore represented only schematically.
  • the pressure source may, for instance, be an engine-driven gear pump or a piston pump, the output pressure is held, by means of a pressure-regulating valve 23, at a desired pressure p for instance in the order of 200 bar or 400 bar.
  • the pressure regulating valve 23 may be combined with a pressure reservoir (not shown); the construction of this reservoir and also that of the pressure-regulating valve 23 are well known.
  • the fuel which is supplied via the fuel supply line 21 flows past an electromagnet 25 the solenoid of which is cooled, and into a fuel supply chamber 28 via a fuel inlet duct 27.
  • the fuel supply chamber 28 is connected with the pressure chamber 22 via a central, fuel'filled recess or bore 29 in valve needle 12 which recess extends substantially along the longitudinal axis of the valve needle and communicates with pressure chamber 22 via a throttle passage 31 having a throttling diameter F which is shown in FIGS. 1 and 2 as an oblique reduced diameter bore opening out of the beveled wall of the shoulder 18 of valve needle 12.
  • the fuel pressure p prevailing in fuel supply chamber 28 is exerted, on the one hand, on the upstream annular end wall 32 of valve needle 12 remote from valve cone 15, and, on the other hand, on an armature 33 which is in contact with fuel on at least two opposite sides thereof (FIGS. 1 and 2), so that no excess hydraulic force will act on the armature 33 in the direction in which the valve opens.
  • the armature 33 is guided with only a small tolerance in the electromagnet 25 in order to maintain gap losses as low as possible.
  • the armature 33 and the valve needle 12 are articulatedly connected with one another by means of a connecting member 34, whereby any axial misalignment between armature 33 and valve needle 12 occurring during manufacture will be compensated.
  • a return spring 35 urges the valve cone 14 of valve needle 12 on to the valve seat 15 and thereby holds the injection valve in the closed position shown in FIG. 1.
  • a central bore 36 through the upstream part of valve housing 9, remote from the nozzle apertures 16, to which bore 36 there is connected a fuel return line 37 which is free from pressure or is pressure-relieved.
  • This fuel return line 37 leads to a fuel tank 38 from which the pressure source 19 takes in fuel via a suction line 39.
  • a compensating piston 41 is interposed, which piston is housed with a sealing fit in a guiding bore 42 being an enlarged zone of bore 36. The compensating piston 41 thus seals off bore 36 and fuel supply chamber 28 against the fuel return line 37.
  • the compensating piston 41 has a diameter D, which is approximately equal to the diameter D of valve seat 15.
  • a first frontal face 43 of piston 41 facing toward return line 37 is pressure-relieved as described above, i.e., it is exposed only to atmospheric pressure, apart from possible small amounts of leaking fuel that may leak through to return line 37.
  • the opposite frontal face 44 of the compensating piston 41 is exposed to the fuel pressure p; from the pressure source 19.
  • the piston 31 is coupled to the armature 33 and also via an elastically bendable connecting member 45, which preferably consists of steel spring wire, to the connecting member 34 and by means of the latter to the valve needle 12.
  • FIG. 2 shows the injection valve 111 in its open position.
  • the electromagnet 25 When the electromagnet 25 is energized, the armature 33 is attracted and moves the valve needle 12 by means of connecting member 34 and against the force of return spring 35 to a position in which valve seat 15 is held open so that fuel can flow from the supply line 21 via inlet duct 27, fuel supply chamber 28 and central recess 29 and from there through throttle passage 31 and the pressure chamber 22 past the open valve seat 15 to the nozzle apertures 16, through which the fuel is injected into the combustion space (not shown) of the engine, in a manner known per se.
  • a second embodiment of a fuel injection valve 50 according to the invention which has been represented in FIG. 3 and is destined for being attached to a diesel engine, comprises a first housing part 51 and a nozzle body 53 inserted in a stepped bore 52 therein, as well as a spring casing 54.
  • an electromagnet 55 and a second housing part 56 which are screwed together, to form a fluid-tight unit, with the aid of the compressing force of a compression nut 57, sealing rings and the like sealing means, which have not been designated further, being interposed between the component parts of the unit where needed.
  • An apertured connecting part 5%, bearing a female plug member 60 to be connected to a source of electric current for the electromagnet 55, and an annular connecting piece 59 having a radially extending socket 61 for connection to a fuel supply line 21 are mounted on the second housing part 56 and secured therein against rotation by means of a pin 62, and by tightening the whole assembly by means of a nut 63.
  • the parts 59 and 61 and the nut 63 are centered on a tubular socket part 64 of valve housing part 56.
  • Socket part 64 has a central axial bore 65 which is pressure-relieved and is provided with an inner threading for connection to a fuel return line 37 leading to a fuel reservoir, in the same manner as shown for line 37 in FIG. 1.
  • line 21 is connected to a pressure source as shown with regard to line 21 in FIG. 1.
  • a valve needle 67 is inserted fluid-tight and guided by means of its cylindrical guiding part 68 in a bore 66 of nozzle body 53.
  • the diameter of guiding part 68 has been designated by D
  • a pressure chamber 72 is arranged in nozzle body 53 adjacent a valve seat 71 disposed upstream of a nozzle orifice 69; as shown in detail in FIG. 3a, on an enlarged scale, a valve cone 73 of valve needle 67 is seated fluid-tight on the valve seat 71, having the diameter D and obturates nozzle orifice 69.
  • Valve cone 73 bears a throttling pin 74 which penetrates into the nozzle orifice 69.
  • a nozzle orifice controlled in this manner is generally known used in pin-controlled nozzles.
  • the slope of the conical bore forming the valve seat 71 in the nozzle body 53 is conventionally steeper than the slope of the valve cone 73 of the valve needle 67, in order to obtain an exactly defined valve seat as indicated by the diameter D in FIG. 3a.
  • an exchangeable screw member 81 is inserted, in which there is provided a throttling passage 82 having a throttling diameter designated as F
  • An armature 83 of electromagnet 55 is guided in the magnet with only a small tolerance and is coupled with radial play by means of a coupling disc 84 to a connecting rod 85 one end of which is connected to the armature 83, while the other end of rod 85 is connected to the valve needle 67 by means of an articulated joint 86.
  • This type of connecting means between the valve needle and the armature 83 permits a prescribed narrow guidance of the armature 83 in the magnet 55, whereby a maximum of magnetic force can be attained in a minimum of space without any impairing influence of guiding and frictional force on the operation of the valve.
  • the articulated joint 86 consists of a rod head 87 which is screwed on the connecting rod 85 and has a transverse bore 88 being deeply beveled at both ends thereof, and of a pin 89 which is inserted into a transverse bore 91 of the valve needle 67 and into the aforesaid transverse bore 88.
  • a rod head 87 has radial play relative to the enlarged zone 80 of the axial valve needle bore 78 and as the transverse bore 88 in the rod head 87 is beveled over about half its total length, an articulated joint is effected between the connecting rod 85 and the valve needle 67. Deviations of the longitudinaI axes of valve needle 67 and armature 83 are thereby prevented from exercising a disadvantageous influence on the operation of the injection valve.
  • a compensating piston 93 is coupled to the end of the connecting rod 85 bearing the armature 83, by means of an elastically bendable, longitudinally rigid connecting member 92.
  • the compensating piston 93 is slidably fit into a guide bore 94 in a guide sleeve 95, which latter is in turn exchangeably inserted in the second housing part 56 and is held therein by means of a screw 96.
  • the flexibly elastic connecting member 92 is made advantageously from spring steel wire in order to avoid transverse forces caused by misalignment.
  • the exchangeable guide sleeve 95 and the replaceable screw member 81 facilitate adjustment of the injection valve to suit the various engine characteristics to which, moreover, the valve seat diameter and the shape of the valve needle must be individually adapted in a manner known per se.
  • the diameter D of the compensating piston 93 is equal, or at least approximately equal, to the diameter D of the valve seat 71, in order to balance, or at least to balance approximately, the hydraulic forces which are exerted upon the valve needle 67 when the injection valve 50 is in closed position.
  • the compensating piston 93 has a first end face 97 and a second end face 98 which latter is exposed to the fuel pressure p of the pressure source. This second end face 98 is in communication, via a central bore 99 in the second housing part 56 and a central bore 101 of electromagnet 55, with the spring chamber 77 which is in turn connected to the fuel supply line 21' in a manner described hereinbefore.
  • the compensating piston 93 bears in its periphery indented grooves 93a which form a labyrinth seal so that the amount of fiiel returned through leakage via the fuel return line 37' to the reservoir is kept small.
  • the admitted fuel is led about the solenoid 102 of electromagnet 55.
  • a chamber 103 surrounding solenoid 102 communicates with the bore 75 via a channel 104, and further via a slanted duct 105 with the central bore 101 of the electromagnet 55 and with the spring chamber 77; the fuel flowing through chamber 103 cools the solenoid 102 of electromagnet 55.
  • Spring chamber 77, central bore 101 of the electromagnet 55 and the central bore 99 in the second housing part 56 constitute a fuel access path 106 from which fuel pressure p of the pressure source can be exercised simultaneously on the second end face 98 of the compensating piston 93 as well as on a stepped end face 107, facing toward the spring chamber 77, of the valve needle 67.
  • the same feeding pressure p also prevails in the axial bore 78 of valve needle 67 and in the pressure chamber 72, for, when there is no flow of fuel, the throttling passage 82 has no effect.
  • Valve needle 67 is held in the shown closure position by a return spring 108 which is supported, on the one hand, on an annular shoulder 109 in spring chamber 77 and, on the other hand, on an annular shoulder 111 of valve needle 67. It is a function of the compensating piston 93, to be explained in detail hereinafter, to provide for a balance of the forces caused by the fuel pressure p; and acting on the valve needle 67 when the injection valve 50 is in closed position. To achieve this end, it is advantageous so to adjust the force of return spring 108 in relation to the force of the electromagnet 55 that a desired closing and opening speed valve needle 67 is attained. Moreover, the return spring 108 serves to overcome the force, acting in the opening direction in the injection valve 50, ofa very weak holding spring 112 which merely retains the armature 83 in position and urges it against the coupling disc 84.
  • a third embodiment of a fuel injection valve, designated by 120, of which only the nozzle part turned toward the combustion space has been shown in FIG. 4, is in particular distinguished from the second embodiment, shown in FIG. 3, by the fact that it comprises a nozzle having a cavity with radial orifices downstream of the valve seat.
  • a valve needle 67' has a guiding portion 68 and adjacent thereto a reduced diameter needle portion 121 provided with a valve cone 73'.
  • the valve cone 73' obturates a valve seat 71 in a nozzle body 53' which is fastened fluid-tight under tension in a known manner to a housing part 123 of the injection valve by means of a coupling nut 122.
  • the nozzle body 53 has downstream of valve seat 71 a closed bottom cavity 124 which communicates with the combustion space (not shown) of the engine through radial nozzle orifices 125 provided in wall of nozzle body 53 surrounding the cavity.
  • a fuel flow duct 78' which corresponds to the axial valve needle bore 78 in FIG. 3 and is provided with transverse bores 79', connects a spring chamber 77' with a pressure chamber 7 2' adjacent the valve seat 71.
  • Fuel flow duct 78 is located only in the guiding portion 68' of valve needle 67' so as not to weaken the structure of needle portion 121.
  • a screw member 81' provided with a throttle passage 82 is screwed into flow duct 78.
  • a return spring 108' similar to that in injection valve 50 of FIG. 3, and a connecting rod 85 connects the valve needle 67' with the armature (not shown) of an electromagnet and with a compensating piston (not shown).
  • the parts not shown in this figure correspond essentially to those of the second embodiment shown in FIG. 3.
  • the fourth embodiment of an injection valve 130 the lower portion of which, essential to the illustration of the invention, has been represented in FIG. has a valve needle 132 which is guided with its guiding portion 131 in a nozzle body 133 and possesses a slim needle portion 132a similar to that of valve needle 67 in FIG. 4.
  • a valve cone 134 borne by this needle portin 132a at its downstream end, there is obturated a valve seat 135 having the seat diameter D
  • This valve seat 135 controls the flow of fuel from a pressure chamber 136 located adjacent the valve seat 135, to nozzle orifices 137.
  • the upstream part of fuel injection valve 130 is constructed similar to that of the injection valves and 120 in FIGS. 1., 2 and 4.
  • the diameter of this compensating piston has been designated by D
  • the piston 138 has a first frontal face 141 which faces downstream toward valve needle 67' and forms one side wall of a fuel storing chamber 142 which is pressure-relieved and which is connected via a leak fuel duct 143 to a fuel return line (not shown) leading to a fuel reservoir (not shown).
  • the chamber 142 and the duct 143 correspond to the pressure-relieved duct 65 in FIG. 3.
  • Fuel from the pressure source (not shown) has access to the second frontal face 144 of compensating piston 138 and to a fuel supply duct 145, so that both these parts are exposed to the fuel pressure p
  • the fuel supply duct 145 is provided in a housing part 147 of a valve housing 148 and extends parallel to the chamber 142 and to a guiding bore 146 which houses the compensating piston 138.
  • a throttle means in the form of a throttle bore 151 in a transverse plate 149.
  • the part of the duct 145 located downstream of throttle bore 151 has been designated as 145a and opens into the pressure chamber 136. In the latter, the fuel acts upon an annular shoulder 152 of valve needle 132, which shoulder is limited externally by the guiding portion 131, having the diameter D of valve needle 132,
  • the shoulder 152 therefore, represents an annular surface when seen in vertical projection.
  • the fuel supply duct 245 has its end remote from the pressure chamber 136 a zone slanted toward the valve axis, 14512, by which it is connected to a fuel supply chamber 153.
  • the part of this fuel supply chamber 153 which has been illustrated in FIG. 5 is delimited, on the downstream side, by the second frontal face 144 of compensating piston 138 and is formed by a part of the central guiding bore 146 and by the internal recess of an electromagnet (not shown) which corresponds to the recess designated by 101 in FIG. 3.
  • Fuel supply chamber 153 is exposed to the fuel pressure p from the pressure source.
  • the compensating piston 138 is connected via a connecting rod 154 to the armature (not shown) of the electromagnet, and the piston is coupled with forcetransmission to the valve needle 132 via a rigid connecting member 155.
  • the cross sectional area F 33 which corresponds to the diameter D of compensating piston 138 is smaller, by the cross section area F 53 corresponding to the diameter D of the valve seat 135, than the cross sectional area F which corresponds to a diameter D of the guiding portion 131 of valve needle 132, so that the hydraulic forces exerted on the valve needle in closed position are the same in the opening as well as in the closing direction.
  • the rigid connecting member 155 is provided in its middle region with a collar 157 serving as an abutment for a return spring 156; the collar 157 bears a spherically shaped face 158 for a spring seat disc 159 which supports one end of return spring 156.
  • This spring seat disc 159 is adapted to the spherical shape of face 158 and thus permits its position to be adapted to a possible inclined positioning of the return spring 156.
  • the ends of the connecting member 155 are shaped as spherical heads 161 and 162, and each of these spherical heads is supported in a correspondingly spherically shaped recess 163 and 164, respectively, of the compensating piston 138 and of the valve needle 132.
  • the centers of the corresponding recesses are located at least approximately on the central axes of the compensating piston 138 and the valve needle 132, respectively.
  • the arrangement of the electromagnet, its solenoid and its armature is similar to that shown in FIG. 3, the electromagnet being mounted on the upstream face of valve housing part 123 (in FIG. 4) or 147 (in FIG. 5) and fastened to these parts by a compression nut as shown in FIG. 3 or the like known means.
  • a fuel injection valve 171) shown in FIG. 6 as a fifth embodiment comprises a valve needle 174 guided by means of a hollow guiding plug portion 171 thereof in an axial bore 172 provided in a nozzle housing 173.
  • the axial bore 172 extends through the nozzle housing 173 in the region of its end face 175 facing toward the combustion space (not shown), and has the guiding plug portion 171 fit fluid-tight therein.
  • the armature 179 is housed with play in an axial bore 188 of the electromagnet casing 177.
  • the nozzle housing 173, the intermediary cylindrical part 176 as well as the electromagnet casing 177 are coupled together by means of a coupling nut 182 to form a fluid-tight unit constituting the valve housing 183.
  • the electromagnet casing 177 and the coupling nut 182 are only partially illustrated.
  • connecting means for the fuel supply line from a pressure source and for the fuel return line are provided in a manner known per se.
  • a compensating piston 184 having the diameter D is connected positively, or made integral with, the armature 179 and is coupled to the valve needle 174 by means of a transverse pin 185. It thus serves as a connecting member between the armature 179 and the valve needle 174.
  • the compensating piston 184 is ground fluid-tight into a guiding bore 186 of the intermediary cylindrical part 176 and thus seals off a pressure chamber 187, located between the axial bore 172 in nozzle housing 173 and an enlarged downstream zone 186a of guiding bore 186, against an internal chamber 188a which is pressure-relieved and which is a downstream part of axial bore 188.
  • Pressure chamber 187 is exposed to the fuel pressure p, in a manner to be explained further below.
  • a fuel return line for returning leakage fuel to a reservoir is connected to the upstream end of axial bore 188 in a manner not shown; the pressure chamber 178 is connected via ducts 189 in electromagnet casing 177 and ducts 191 and 192 in the intermediary cylindrical part 176 to the pressure source.
  • the hollow guiding plug portion 171 of valve needle 174, having the diameter D has the shape of a nozzle tip having a closed bottom cavity 194 and radial nozzle orifices 195 from he cavity to the outside of the valve 170.
  • the cavity 194 is closed off toward the interior of the valve needle by means ofa plug 196 and is provided with connecting bores 197 inclined upwardly and outwardly and communicating with an annular groove 198 in the external wall of the guiding plug portion 171.
  • valve cone 199 Adjacent the annular groove 198, a valve cone 199 is formed by the frustoconical valve needle portion intermediate the plug portion 171 and a cylindrical portion 174a of larger diameter, forming the upstream end of valve needle 174.
  • the upstream end of bore 172 toward the pressure chamber 187 forms a valve seat 201 engaged by valve cone 199 when valve 170 is closed, as shown in FIG. 6.
  • the valve seat diameter D is equal to the diameter D of the valve needle guiding plug portion 171.
  • the valve seat 201 is always slightly blunted, i.e., it has a radial width of one or two tenths of a millimeter, the valve seat diameter D can be considered as being at least approximately equal to the diameter D of the guiding plug portion 171.
  • the diameter D, of the compensating piston is at least approximately equal to the diameter D of the valve seat 201 and, as the internal chamber 188a of the electromagnet casing 177 is pressure-relieved.
  • the sixth embodiment of a fuel injection valve, 210 is distinguished from the fifth embodiment described in the foregoing, merely by a different construction of the valve needle and of the nozzle housing in the region of the valve seat.
  • the injection valve 210 comprises a valve needle 6 174' being guided in an axial bore 212 in a nozzle housing 173', by means of a valve needle portion shaped as a guiding piston 211. Downstream of the guiding piston 211, the valve needle 174 has a short needle part 213 of reduced diameter bearing a frustoconical part serving as a valve cone 199', which obturates a valve seat 201 as shown in FIG. 7.
  • This valve seat 201' is formed by the edge between a nozzle orifice 215 being an axial bore in the bottom end of nozzle housing 173', and a conical seat 218 in the nozzle housing 173.
  • a spraying plug 214 is connected to the valve cone 199 downstream of and coaxially with valve needle 174.
  • This spraying plug 214 extends with play through the nozzle orifice 215, leaving in the latter an annular gap which is dimensioned for the passage of only a partial amount Q of the total fuel amount Q which is to be injected when operating the engine under full load.
  • the spraying plug 214 has an axial spray bore 216 which opens toward the combustion space of the engine, and which is in communication with the aforesaid annular gap via a transverse bore 217.
  • valve seat diameter D of valve seat 201 is equal to, or at least approximately equal to the diameter D, of the compensating piston 184.
  • injection valve 210 All remaining parts of the injection valve 210, e.g., the armature 179 of electromagnet 178, are identical with the parts as shown in the injection valve of FIG. 6, and have therefore not been designated in FIG. 7.
  • valve needle 12 In the case of injection valve 10 shown in FIGS. 1 and 2, the return spring 35 holds the valve needle 12 in the closed position when the electromagnet 25 is deenergized. In this state, valve cone 14 obturates the valve seat 15 and prevents the flow of fuel present in pressure chamber 22 under the pressure p to the nozzle apertures 16. When the valve is closed, this fuel pressure also prevails in the fuel supply chamber 28. The following forces then act on the valve needle 12:
  • P,- is the force of the return spring and F is the cross sectional area subject to fuel pressure and corresponding to the diameter D of the guiding portion 13 of valve needle 12;
  • the hydraulic forces acting on the valve needle 12 in the opening and in the closing direction must be made only approximately equal, i.e., the diameter D of the compensating piston 41 and, consequently, its cross sectional area F must be slightly smaller than the diameter D of the valve seat 15 and correspondingly, the cross sectional area F of the latter.
  • the electromagnet 25 When energized, the electromagnet 25 must initially overcome the force P which means that the attracting force P of the electromagnet 25 need only be larger than P when F is equal to F It will be seen from the foregoing that, in the case of a complete balance of forces by the compensating piston 41, the fuel pressure p has no influence of the attracting force P of the electromagnet 25 which is required to open te injection valve.
  • the throttle passage 31 opening out of the central needle recess 29. will cause a pressure drop A, between the fuel supply chamber 28 and the pressure chamber 22 such that the hydraulic forces acting upon the valve needle 12 will be equal in the opening as well as in the closing direction, when the valve is open as shown in FIG. 2.
  • the throttle cross sectional area F of the throttle passage 31 must be so dimensioned.
  • Fy is the valve opening cross sectional area of the injection valve.
  • the cross sectional area F is equal to the valve seat cross sectional area F so that the following equation applies to the first embodiment:
  • the cross sectional area F of the throttling passage 31 which produces the required pressure drop Ap in a given fuel pressure p is also effective with variable fuel pressures and fuel quantities, for, expressed in a simplified manner, in the case of a smaller or larger fuel pressure p the required pressure drop Ap is also correspondingly smaller or greater.
  • K is a constant representing the flow characteristics and cross sectional areas of the throttling passages which remain always constant.
  • the second embodiment according to FIG. 3 functions generally in the same manner as the first embodiment.
  • This valve cross sectional area F which is subject, in pressure the 72, to the pressure p which has been reduced by the throttling passage 82 when the injection valve 50 is in open position, is a rule considerably smaller than the cross sectional area F of the valve seat 71, which corresponds to the valve seat diameter D Therefore only a very small pressure drop Ap need be generated by the throttling passage 82. If the difference between the diameter D of the valve seat 71 and the diameter of the throttle plug 74 is very small, then it is possible, in particular in the case of low injection pressures, to omit throttling by means of the throttling passage
  • injection valve 50 shown in FIG. 3 when the diameter D of the compensating piston 93 is equal to the diameter D of the valve seat 71, and when the throttling passage 82 is so dimensioned that the pressure p in pressure chamber 72 is sufficiently reduced, in the case of the injection valve 50 being open, so that, as a result, the following equation is valid for injection valves 10, 50 and 120 (FIGS. 1 to 4):
  • the third embodiment namely, the fuel injection valve 120 according to FIG. 4, functions in the same manner as the first embodiment shown in FIGS. 1 and 2.
  • the valve needle 67 controls the valve seat 71' which prevents the flow of the fuel present in pressure chamber 72 to the nozzle openings 125 when the injection valve is closed.
  • a pressure drop controlled by the throttling passage 82 will take place in pressure chamber 72, similar to that occurring in injection valve 10 as shown as in FIG. 2, which pressure drop will compensate the hydraulic forces acting upon the valve needle 67' even when injection valve 120 is open, in the same manner as has been described in connection with FIG. 2.
  • the fuel injection valve 130 is fuel-pressure-relieved in the closed position shown, i.e., the hydraulic forces acting upon the valve needle 132 in the positions of opening and closing due to the fuel pressure p are equal.
  • This pressure balance is attained by the fact that the cross sectional area F corresponding to the diameter D of the compensating piston 138 is equal to the cross sectional area engaged at the valve needle 132 in the pressure chamber 136 in the direction of opening.
  • the cross sectional area F corresponding to the diameter D of the compensating piston 138 is equal to the cross sectional area engaged at the valve needle 132 in the pressure chamber 136 in the direction of opening.
  • a pressure p reduced by Ap due to the throttle bore 151 prevails in pressure chamber 136, and causes the hydraulic forces acting upon the valve needle 132 to be balanced even when this injection valve 130 is in the open position. This is the case, when the force acting in the fuel supply chamber 153 on the compensating piston 138, in the direction of closing movement of the valve needle 132, is equal to the force acting in pressure chamber 136 upon the valve needle 132 in the direction of its opening movement.
  • the armature 179 attracts the valve needle 174 via the compensating piston 184 and the connecting rod 185, and the valve cone 199 thereof clears the valve seat 201.
  • the fuel present under fuel pressure p in the pressure chamber 187 can now flow through the annular groove 198 and the connecting bores 197 into the cavity 194 wherefrom it is injected through nozzle orifices 195 into the combustion space of the engine.
  • the fuel injection valve 210 according to FIG. 7 functions in the same manner as that of F IG. 6, with the exception that the equation D D applies, whereby the desired balance of forces is achieved in the closed valve.
  • valve needle 174' When injection valve 210 is open, an additional force acts on the valve needle 174' in the direction of opening, which force is proportional to the fuel pressure and to the annular area which is limited externally by the valve seat diameter D and internally by the diameter of the spraying plug 114.
  • This force can be neglected when the injection pressure is relatively low and the diameter of the annular area is narrow; in the case of very high injection pressures and a larger ring area diameter, this force can be balanced by means of throttling between spaces located above and below the guiding piston.21l (not shown) in a similar manner as in the case of the injection valves according to FIGS. 1 to 4.
  • an electromagnetically actuated fuel injection valve of the type that has a. a valve housing having a bore, a valve seat, a pressure chamber adjacent said valve seat, and at least one nozzle discharge outlet,
  • connecting means for connecting said armature to said valve needle wherein. upon energization of said electromagnet, said armature lifts said valve needle from said valve seat against the force of said return spring means and against the direction of flow of fuel under pressure into said pressure chamber, thereby establishing communication between the latter and said nozzle discharge outlet, the improvement comprising a compensating piston guided in said bore in a fluid-tight manner and substantially coaxially with said armature and said valve needle, coupling means for coupling said piston to said valve needle, said piston having a pressure-relieved first frontal face and a second frontal face being exposed to fuel pressure and having a cross sectional area sufficiently large so that the hydraulic forces acting on said valve needle in the direction of its opening and in' the direction of its closing, when said injection valve is closed, are at least approximately equal.
  • said throttle means has a throttling cross sectional area whereby, when the injection valve is open, the pressure in the pressure chamber is reduced so that the force acting in said pressure chamber on the valve needle in the direction of opening is at least approximately equal to theforce acting in the same chamber on the valve needle in the opening direction when the injection valve is closed.
  • connecting means further comprise articulated joint means disposed between said connecting rod and said valve needle and comprising a pin extending through said valve needle and through said connecting rod traversely to the valve needle axis, said connecting rod having a traverse bore therethrough, both ends of which are beveled.

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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)
  • Details Of Valves (AREA)
  • Magnetically Actuated Valves (AREA)
US00338305A 1972-03-03 1973-03-05 Electromagnetically actuated fuel injection valve for internal combustion engines Expired - Lifetime US3797756A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2210213A DE2210213C2 (de) 1972-03-03 1972-03-03 Elektromagnetisch betätigbares Kraftstoffeinspritzventil für Brennkraftmaschinen

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US3797756A true US3797756A (en) 1974-03-19

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US (1) US3797756A (da)
JP (1) JPS5712859B2 (da)
DE (1) DE2210213C2 (da)
FR (1) FR2174500A5 (da)
GB (1) GB1422422A (da)
IT (1) IT973282B (da)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3893629A (en) * 1973-08-29 1975-07-08 Diesel Kiki Co Fuel injection device for diesel engines
US3913537A (en) * 1973-08-21 1975-10-21 Bosch Gmbh Robert Electromechanically controlled fuel injection valve for internal combustion engines
US4033513A (en) * 1975-11-06 1977-07-05 Allied Chemical Corporation Electromagnetically operated valve
US4141231A (en) * 1975-07-28 1979-02-27 Maschinenfabrik Peter Zimmer Aktiengesellschaft Machine for applying patterns to a substrate
US4708289A (en) * 1985-06-12 1987-11-24 Vdo Adolf Schindling Ag Injection valve
EP1382839A1 (de) * 2002-07-18 2004-01-21 Robert Bosch Gmbh Ankerbaugruppe für Kraftstoffinjektoren
US20040026646A1 (en) * 2001-07-09 2004-02-12 Hubert Stier Fuel Injection
US20060284129A1 (en) * 2005-06-17 2006-12-21 Krishnaswamy Harish K Electromagnetic actuator and method for controlling fluid flow
US20080277505A1 (en) * 2004-05-18 2008-11-13 Anh-Tuan Hoang Fuel Injector
WO2014048615A1 (en) * 2012-09-26 2014-04-03 Delphi International Operations Luxembourg S.À.R.L. A fluid injector

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES471424A1 (es) * 1977-08-24 1979-01-16 Lucas Industries Ltd Tobera de inyeccion de combustible
JPS5671951U (da) * 1979-11-07 1981-06-13
DE3841010A1 (de) * 1988-12-06 1990-06-07 Bosch Gmbh Robert Elektromagnetisch betaetigbares ventil
DE4302668A1 (de) * 1993-01-30 1994-08-04 Bosch Gmbh Robert Kraftstoffeinspritzeinrichtung für Brennkraftmaschinen
CN108775403A (zh) * 2018-06-21 2018-11-09 湖北三江航天红峰控制有限公司 一种长寿命快速响应电磁阀

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3623460A (en) * 1969-02-28 1971-11-30 Bosch Gmbh Robert Fuel injection valve for internal combustion engines
US3680794A (en) * 1970-08-04 1972-08-01 Bosch Gmbh Robert Electromagnetically operated fuel injection valve

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB297237A (en) * 1927-04-27 1928-09-27 Louis Osborne French Improvements in control valves
DE1025693B (de) * 1953-04-02 1958-03-06 Erich Herion Elektromagnetisch gesteuertes Dreiwege-Ventil mit Entlastungsmitteln

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3623460A (en) * 1969-02-28 1971-11-30 Bosch Gmbh Robert Fuel injection valve for internal combustion engines
US3680794A (en) * 1970-08-04 1972-08-01 Bosch Gmbh Robert Electromagnetically operated fuel injection valve

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3913537A (en) * 1973-08-21 1975-10-21 Bosch Gmbh Robert Electromechanically controlled fuel injection valve for internal combustion engines
US3893629A (en) * 1973-08-29 1975-07-08 Diesel Kiki Co Fuel injection device for diesel engines
US4141231A (en) * 1975-07-28 1979-02-27 Maschinenfabrik Peter Zimmer Aktiengesellschaft Machine for applying patterns to a substrate
US4033513A (en) * 1975-11-06 1977-07-05 Allied Chemical Corporation Electromagnetically operated valve
US4708289A (en) * 1985-06-12 1987-11-24 Vdo Adolf Schindling Ag Injection valve
US20040026646A1 (en) * 2001-07-09 2004-02-12 Hubert Stier Fuel Injection
US7048253B2 (en) * 2001-07-09 2006-05-23 Robert Bosch Gmbh Fuel injection
EP1382839A1 (de) * 2002-07-18 2004-01-21 Robert Bosch Gmbh Ankerbaugruppe für Kraftstoffinjektoren
US8528842B2 (en) * 2004-05-18 2013-09-10 Robert Bosch Gmbh Fuel injector
US20080277505A1 (en) * 2004-05-18 2008-11-13 Anh-Tuan Hoang Fuel Injector
US20060284129A1 (en) * 2005-06-17 2006-12-21 Krishnaswamy Harish K Electromagnetic actuator and method for controlling fluid flow
US9140224B2 (en) * 2005-06-17 2015-09-22 Caterpillar Inc. Electromagnetic actuator and method for controlling fluid flow
WO2014048615A1 (en) * 2012-09-26 2014-04-03 Delphi International Operations Luxembourg S.À.R.L. A fluid injector
CN104662622A (zh) * 2012-09-26 2015-05-27 德尔福国际运营卢森堡有限公司 流体喷射器
CN104662622B (zh) * 2012-09-26 2017-06-23 德尔福国际运营卢森堡有限公司 流体喷射器
US9757748B2 (en) 2012-09-26 2017-09-12 Delphia International Operations Luxembourg S.A.R.L. Fluid injector

Also Published As

Publication number Publication date
FR2174500A5 (da) 1973-10-12
JPS48103919A (da) 1973-12-26
JPS5712859B2 (da) 1982-03-13
IT973282B (it) 1974-06-10
DE2210213C2 (de) 1985-03-28
DE2210213A1 (de) 1973-09-20
GB1422422A (en) 1976-01-28

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