EP0065282A1 - Fuel injection nozzle for internal-combustion engines - Google Patents

Fuel injection nozzle for internal-combustion engines Download PDF

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Publication number
EP0065282A1
EP0065282A1 EP82104180A EP82104180A EP0065282A1 EP 0065282 A1 EP0065282 A1 EP 0065282A1 EP 82104180 A EP82104180 A EP 82104180A EP 82104180 A EP82104180 A EP 82104180A EP 0065282 A1 EP0065282 A1 EP 0065282A1
Authority
EP
European Patent Office
Prior art keywords
hollow needle
valve
needle
injection nozzle
nozzle body
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP82104180A
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German (de)
French (fr)
Other versions
EP0065282B1 (en
Inventor
Kurt Seifert
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from DE19813120044 external-priority patent/DE3120044A1/en
Priority claimed from DE19813130621 external-priority patent/DE3130621A1/en
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP0065282A1 publication Critical patent/EP0065282A1/en
Application granted granted Critical
Publication of EP0065282B1 publication Critical patent/EP0065282B1/en
Expired legal-status Critical Current

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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
    • F02M61/1806—Injection nozzles, e.g. having valve seats; Details of valve member seated ends, not otherwise provided for characterised by the arrangement of discharge orifices, e.g. orientation or size
    • F02M61/182—Discharge orifices being situated in different transversal planes with respect to valve member direction of movement
    • 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
    • F02M45/00—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship
    • F02M45/02—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship with each cyclic delivery being separated into two or more parts
    • F02M45/04—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship with each cyclic delivery being separated into two or more parts with a small initial part, e.g. initial part for partial load and initial and main part for full load
    • F02M45/08—Injectors peculiar thereto
    • F02M45/086—Having more than one injection-valve controlling discharge orifices
    • 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
    • F02M61/042—The valves being provided with fuel passages
    • F02M61/045—The valves being provided with fuel discharge orifices
    • 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
    • F02M61/08—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 opening in direction of fuel flow

Definitions

  • the invention is based on a fuel injection nozzle according to the preamble of the main claim.
  • Injection nozzles of this type are distinguished by the fact that the section of the fuel channel which adjoins the valve seat downstream and is used for further fuel preparation and spray jet shaping can be designed and dimensioned relatively freely without obstruction by a closing member, and in addition that the fuel passes through the installation space for the closing spring is performed so that special measures to prevent or eliminate leak oil are eliminated.
  • These injection nozzles therefore combine the advantages of nozzles with an inwardly opening valve needle (I nozzle) with those of nozzles with an outwardly opening valve needle (A nozzle), without, however, having their disadvantages.
  • the hollow needle is supported in the closed position via the valve seat on the valve needle ab, which in turn rests on a shoulder fixed to the housing.
  • the valve needle is pressed against the housing-fixed shoulder by a spring.
  • the valve seat is relatively heavily stressed and, in addition, in the open position of the valve, an exact position of the valve needle with respect to the hollow needle is not guaranteed because the valve needle is only held firmly on the stop fixed to the housing. It also appears disadvantageous that the bearing gap between the hollow needle and the nozzle body is not shielded against the combustion chamber of the machine in the closed position of the valve, so that the sliding properties of the hollow needle can deteriorate over time.
  • valve seat is no longer loaded by the closing spring acting on the hollow needle, but by the valve spring pressing against the valve needle, which can be dimensioned weaker than the closing spring.
  • valve spring pressing against the valve needle which can be dimensioned weaker than the closing spring.
  • an exact position of the valve needle with respect to the hollow needle is ensured in the open position of the valve, because this position is determined by two shoulders fixed to the housing, that is to say by positive locking.
  • the stop shoulder for the hollow needle and its counter shoulder are designed according to the features of claim 2 is particularly advantageous.
  • the bearing gap between the hollow needle and the nozzle body is covered in the closed position of the hollow needle against the combustion chamber of the machine, so that proper guidance of the hollow needle in the nozzle body is ensured for a long time.
  • the hollow needle can be designed as a closing member which cooperates with the nozzle body and opens outwards to control further spray openings.
  • This arrangement is particularly advantageous in the case of cross-section-controlled hole and pin nozzles depending on the valve stroke.
  • the fuel guide can be freely designed downstream of the valve seat (s) and in particular divided into several spray holes or spray hole groups, the cross-section and direction of which can be adapted to the requirements of the respective application.
  • the hollow needle can control a first spray hole cross section with the nozzle body and a second spray hole cross section with the valve needle.
  • the means for retaining the valve needle with respect to the hollow needle moving in the opening direction can be arranged such that they come into effect immediately after the opening movement of the hollow needle begins. In this case, that of Hollow needle and valve needle controlled spray hole cross section opened, while the other spray hole cross section is only released after a partial stroke of the hollow needle.
  • the injection sequence can also be controlled so that the means for retaining the valve needle come into effect only after a first partial stroke of the hollow needle corresponding to a pre-injection phase. It is thereby achieved that the first spray hole cross section, which is arranged further at the edge of the combustion chamber, is opened by the hollow needle, and that the second spray hole cross section, which is arranged further towards the center of the combustion chamber, is only released by the valve needle at the beginning of the main injection phase. It is also achieved that after the first partial stroke of the hollow needle with the injection quantity, the closing pressure and thus the fuel pressure in front of the valves increases suddenly, so that in the partial and full load range of the internal combustion engine a perfect preparation of the fuel is guaranteed.
  • the function of a conventional perforated nozzle with an inwardly opening valve needle is obtained with respect to the second spray hole cross section, without taking measures to eliminate leakage oil.
  • the hollow needle can expediently be designed according to the features of claim 11 and control a plurality of spray holes forming the first spray hole cross section in the nozzle body.
  • the first spray hole cross section is formed by transverse bores in the hollow needle, which emerge from the guide bore of the nozzle body after a partial stroke of the hollow needle.
  • Figures 1 to 4 each show a partial section through one of the exemplary embodiments.
  • the injection nozzle according to FIG. 1 has a nozzle body 10 which is clamped to a nozzle holder 14 by a screw body 12.
  • a guide bore 16 for a hollow needle 18 and a bore 20 of larger diameter is formed in the nozzle body 10 and merges into the guide bore 16 on a shoulder 22.
  • a projection 24 of the nozzle holder 14 protrudes into the bore 20, which is provided with a bore 26 and at the front end with a smaller opening 28, the cross section of which has two surfaces.
  • a shoulder 30 fixed to the housing and having a circumferential contact surface is turned away from the injection-side end of the nozzle.
  • the hollow needle 18 has a longitudinal bore 36 extending from its upper end face 32, which leads to a conical valve seat 38, which is followed downstream by a blind hole 40 with spray holes 41, 42 leading to the outside in the front end of the hollow needle 18 designed as a tip 43.
  • the hollow needle 18 is provided with a section 48 which is slightly weakened in the outer diameter and which, in the vicinity of its transition to an un weakened section 50 guided in the nozzle body 10, has a transverse bore 52.
  • the section 48 is followed at the top by a head 54 provided with two surfaces, which, with the required play, protrudes into the opening 28 and secures the hollow needle 18 against rotation.
  • a conical annular shoulder 56 is further formed in the vicinity of the valve seat 38, which cooperates with a correspondingly shaped counter shoulder 58 at the front end of the nozzle body 10.
  • a closing spring 60 is arranged in the bore 20, which is supported at the bottom on a flange 62 of a bush 64 resting on the shoulder 22, which surrounds the section 48 of the hollow needle 18 with play. At the upper end, the closing spring 60 engages a pressure ring 66 which abuts an annular shoulder 68 of the hollow needle 18 formed between the section 48 and the head 54. The highlighted by the closing spring 60.
  • Called upward stroke (closing stroke) of the hollow needle 18 is limited by the shoulders 56 and 58 to the hollow needle 18 and nozzle body 10, which are designed as valve surfaces and seal the bearing gap between the latter and the nozzle body 10 against the combustion chamber in the closed position of the hollow needle 18.
  • a valve needle 70 is slidably guided in the longitudinal bore 36 of the hollow needle 18 and has a sealing cone 72 which cooperates with the valve seat 38 at the end on the injection side.
  • the sealing cone 72 is formed on a section 74 of the valve needle 70 which is somewhat weakened in diameter and which merges on a shoulder 76 into the unattenuated section of the valve needle 70.
  • the shoulder 76 lies somewhat above the transverse bore 52 in the hollow needle 18, so that the annular space 78 formed between the section 74 of the valve needle 70 and the wall of the longitudinal bore 36 in the hollow needle 18 via the transverse bore 52, the annular play between the hollow needle 18 and the bushing 64 , and via one or more transverse bores 80 in the bushing 64 is connected to the bore 20 in the nozzle body 10.
  • the valve needle 70 protrudes a bit from the hollow needle 18 at the top and is provided there with an annular collar 82, on the upper end face of which a valve spring 84 engages, which is supported on a threaded bushing 86 screwed into the bore 26.
  • the valve spring 84 endeavors to press the valve needle 70 against the valve seat 38 in the hollow needle 18. This is achieved in the closed position of the hollow needle 18 shown in the drawing, in which the collar 82 of the valve needle 70 is still removed from the shoulder 30 on the nozzle holder 14 by the stroke h 1 .
  • the collar 82 lies against the shoulder 30, after which the valve needle 70 is prevented from moving along with the hollow needle 18.
  • the total stroke h 2 of the hollow needle 18 is limited by the bushing 64, on the upper end of which the pressure ring 66 comes to rest.
  • the threaded bushing 86 is provided with a bore 88 for supplying the fuel.
  • the fuel path then leads via the bore 26 and an edge recess 90 surrounding the shoulder 30 in the neck 24 of the nozzle holder 14 into the bore 20, where the fuel acts on the end face 32 of the hollow needle 18 and on this force opposing the closing spring 60 in the direction of Combustion chamber.
  • the fuel passes through the transverse bore 52 in the hollow needle 18 into the annular space 78 between the hollow needle 18 and the valve needle 70 and exerts a further force on the hollow needle 18 via the narrow annular surface 92 above the valve seat 38.
  • the fuel also exerts a downward-acting resulting force on the valve needle 70 which, in support of the valve spring 84, presses the valve needle 70 against the valve seat 38.
  • the hollow needle When the fuel pressure rises at the beginning of an injection stroke, the hollow needle is moved downward out of the nozzle body 10 by compressing the closing spring 60. Under the influence of the valve spring 84 and the fuel pressure, the valve needle 70 can only follow this movement by the small distance h 1 , after which the collar 82 strikes the shoulder 30 and forces a relative movement of the valve needle 70 with respect to the hollow needle 18 which is moving further. This relative movement has approximately the same effect in relation to the fuel control in the injection region as an inwardly moving valve needle with a fixed valve seat.
  • the arrangement described has the advantage that a leakage oil flow in the guide of the valve needle 70 or the hollow needle 18 is not disruptive or does not occur and therefore no means for its removal need to be provided.
  • the closing spring 60 returns the hollow needle 18 to the starting position, in which it strikes with its shoulder 56 on the shoulder 58 of the nozzle body 10.
  • the two shoulders 56 and 58 then form a valve-like closure which prevents the combustion gases from accessing the bearing gap between the hollow needle 18 and the nozzle body 10.
  • the valve needle 70 hits the valve seat 38, after which the fuel discharge from the spray holes 41, 42 is interrupted.
  • the valve needle 70 then lifts from the shoulder 30 by the stroke h 1 .
  • the stroke h 1 is dimensioned just so large in view of the tolerances to be permitted in production that the valve needle 70 can rest safely on the valve seat 38 in the closed position of the hollow needle 18.
  • the exemplary embodiment according to FIG. 2 corresponds to that according to FIG. 1 in the details described so far, except that the hollow needle 18 itself forms the closing member for a valve device which controls a second group of spray holes 94 and 96 which run in the nozzle body 10 .
  • the hollow needle 18 is provided with a transverse bore 98 and an annular groove 100 in the circumference of the jacket, into which the transverse bore 98 opens at both ends.
  • the collar 82 of the valve needle 70 is here removed from the shoulder 30 fixed to the housing by the partial stroke h 1 , which is now used not only to eliminate manufacturing tolerances but also to control the two groups 41, 42 and 94, 96 of the spray holes as a function of the stroke.
  • the spray holes 94 which in their entirety result in a first spray hole cross section I, are first produced via the annular groove 100 and opened 96, the valve spring 84 holding the valve needle 70 against the valve seat 38 of the hollow needle 18.
  • the valve needle 70 is retained relative to the latter, as a result of which the spray holes 41, 42, which in their entirety result in a second spray hole cross section II, are opened.
  • the processes described take place in the reverse order.
  • the arrangement could also be made by appropriate selection of the distance of the transverse bore 98 from the sealing cone 72 on the valve needle 70 so that first the sealing cone 72 lifts off the valve seat 38 and only then is the second group 94, 96 of the spray holes opened.
  • the injection nozzle according to FIG. 2 also has the advantage that when opening the spray holes 41, 42 or the second spray hole cross section II and the associated sudden increase in the overall spray hole cross section, a pressure jump occurs in the closing force, which occurs due to the interception of the force of the valve spring 84 is caused and advantageously ensures that the fuel is then processed and atomized as well as in the first partial stroke h 1 .
  • the exemplary embodiment according to FIG. 3 differs from the one described above only in that the shoulder 56 of the hollow needle 18 is arranged upstream of the first spray hole cross section I and cooperates with an inner shoulder 58 of the nozzle body 10.
  • the shoulders 56 and 58 which cooperate in the closed position like a valve, additionally seal the annular space 78 against the first spray hole cross section I.
  • the spray sequence can also be reversed with regard to the spray hole cross sections I and II.
  • the exemplary embodiment according to FIG. 4 is a further modification of the exemplary embodiment according to FIG. 2.
  • the spray hole cross section I is formed here by spray holes 110 and 112 in the hollow needle 18, which in the closed position of the hollow needle 18 is covered by an overlap 114 and by that between the shoulders 56 and 58 valve seat formed on the hollow needle 18 and nozzle body 10 are sealed off from the combustion chamber.
  • the spray holes 110 ′ and 112 emerge from the guide bore in the nozzle body 10, so that the channels 46, 47 provided in the injection nozzle according to FIG. 2 are unnecessary in the nozzle body 10.
  • the injection nozzle according to FIG. 4 also has the advantage that the spray hole cross-section I is additionally sealed in the closed position of the hollow needle 18 by the valve seat formed between the shoulders 56 and 58.
  • the sequence of opening the spray hole cross sections I and II can be chosen as desired by coordinating the forward stroke h 1 and overlap 114.

Abstract

Kraftstoff-Einspritzdüse für Brennkraftmaschinen, mit einer Hohlnadel (18), in der eine Ventilnadel (70) verschiebbar gelagert ist, welche mit einem inneren Ventilsitz (38) der Hohlnadel (18) zusammenarbeitet. Der Ventilnadel (70) ist eine Ventilfeder (84) und ein gehäusefester Anschlag (30) zugeordnet, welcher die Ventilnadel (70) gegenüber der sich in Öffnungsrichtung bewegenden Hohlnadel (18) zurückhält, wobei das Ventil aufgesteuert wird. Die Schliessbewegung der Hohlnadel (18) wird durch einen Anschlag (58) am Düsenkörper (10) begrenzt, welcher zweckmässig mit einer Gegenschulter (56) an der Hohlnadel eine brennraumseitige Abdichtung für den Lagerspalt zwischen Hohlnadel (18) und Düsenkörper (10) bildet. Die Hohlnadel (18) kann vorteilhaft als ein mit dem Düsenkörper (10) zusammenarbeitendes, nach aussen öffnendes Schliessglied zur Steuerung weiterer Spritzöffnungen ausgebildet sein. Die Einspritzdüse hat den Vorteil, dass ein leckölloser Betrieb mit über dem Nadelhub zeitlich gesteuertem Öffnen von zwei Spritzlochquerschnitten möglich ist.Fuel injection nozzle for internal combustion engines, with a hollow needle (18) in which a valve needle (70) is slidably mounted, which cooperates with an inner valve seat (38) of the hollow needle (18). A valve spring (84) and a stop (30) fixed to the housing are assigned to the valve needle (70), which stops the valve needle (70) from the hollow needle (18) moving in the opening direction, the valve being opened. The closing movement of the hollow needle (18) is limited by a stop (58) on the nozzle body (10) which, with a counter shoulder (56) on the hollow needle, expediently forms a combustion chamber-side seal for the bearing gap between the hollow needle (18) and the nozzle body (10). The hollow needle (18) can advantageously be designed as an outwardly opening closure member which cooperates with the nozzle body (10) to control further spray openings. The injection nozzle has the advantage that leak-free operation is possible with the opening of two spray hole cross-sections that are timed over the needle stroke.

Description

Stand der TechnikState of the art

Die'Erfindung geht aus von einer Kraftstoff-Einspritzdüse nach der Gattung des Hauptanspruchs. Derartige Einspritzdüsen zeichnen sich dadurch aus, daß der an den Ventilsitz sich stromab anschließende, zur weiteren Kraftstoffaufbereitung und Spritzstrahlformung dienende Abschnitt des Kraftstoffkanals ohne Behinderung durch ein Schließglied verhältnismäßig freizügig gestaltet und bemessen werden kann, und daß außerdem der Kraftstoff durch den Einbauraum für die Schließfeder hindurch geführt ist, so daß besondere Maßnahmen zur Verhinderung bzw. Beseitigung von Lecköl entfallen. Diese Einspritzdüsen vereinigen daher die Vorteile von Düsen mit nach innen öffnender Ventilnadel (I-Düse) mit jenen von Düsen mit nach außen öffnender Ventilnadel (A-Düse), ohne jedoch mit deren Nachteilen behaftet zu sein.The invention is based on a fuel injection nozzle according to the preamble of the main claim. Injection nozzles of this type are distinguished by the fact that the section of the fuel channel which adjoins the valve seat downstream and is used for further fuel preparation and spray jet shaping can be designed and dimensioned relatively freely without obstruction by a closing member, and in addition that the fuel passes through the installation space for the closing spring is performed so that special measures to prevent or eliminate leak oil are eliminated. These injection nozzles therefore combine the advantages of nozzles with an inwardly opening valve needle (I nozzle) with those of nozzles with an outwardly opening valve needle (A nozzle), without, however, having their disadvantages.

Bei den bekannten Einspritzdüsen der eingangs erwähnten Gattung (DE-PS 828 327) stützt sich die Hohlnadel in der Schließlage über den Ventilsitz an der Ventilnadel ab, die ihrerseits an einer gehäusefesten Schulter anliegt. Zum Zurückhalten der Ventilnadel gegenüber der in Öffnungsrichtung sich bewegenden Hohlnadel wird die Ventilnadel durch eine Feder an die gehäusefeste Schulter angedrückt. Bei dieser bekannten Ausführung wird der Ventilsitz verhältnismäßig stark beansprucht und außerdem ist in der Offenstellung des Ventils eine exakte Stellung der Ventilnadel gegenüber der Hohlnadel wegen des nur kraftschlüssigen Festhaltens der Ventilnadel am gehäusefesten Anschlag nicht gewährleistet. Auch erscheint nachteilig, daß der Lagerspalt zwischen Hohlnadel und Düsenkörper in der Schließstellung des Ventils gegen die Brennkammer der Maschine nicht abgeschirmt ist, so daß sich die Gleiteigenschaften der Hohlnadel im Lauf der Zeit verschlechtern können.In the known injection nozzles of the type mentioned at the beginning (DE-PS 828 327), the hollow needle is supported in the closed position via the valve seat on the valve needle ab, which in turn rests on a shoulder fixed to the housing. To hold the valve needle back from the hollow needle moving in the opening direction, the valve needle is pressed against the housing-fixed shoulder by a spring. In this known embodiment, the valve seat is relatively heavily stressed and, in addition, in the open position of the valve, an exact position of the valve needle with respect to the hollow needle is not guaranteed because the valve needle is only held firmly on the stop fixed to the housing. It also appears disadvantageous that the bearing gap between the hollow needle and the nozzle body is not shielded against the combustion chamber of the machine in the closed position of the valve, so that the sliding properties of the hollow needle can deteriorate over time.

Vorteile der ErfindungAdvantages of the invention

Die erfindungsgemäße Anordnung mit den kennzeichnenden Merkmalen des Hauptanspruchs hat demgegenüber den Vorteil, daß der Ventilsitz nicht mehr durch die die Hohlnadel beaufschlagende Schließfeder, sondern durch die gegen die Ventilnadel drückende Ventilfeder belastet ist, welche schwächer als die Schließfeder bemessen werden kann. Außerdem ist in der Offenstellung des Ventils eine exakte Stellung der Ventilnadel gegenüber der Hohlnadel gewährleistet, weil diese Stellung durch zwei gehäusefeste Schultern, also durch Formschluß, bestimmt ist.The arrangement according to the invention with the characterizing features of the main claim has the advantage that the valve seat is no longer loaded by the closing spring acting on the hollow needle, but by the valve spring pressing against the valve needle, which can be dimensioned weaker than the closing spring. In addition, an exact position of the valve needle with respect to the hollow needle is ensured in the open position of the valve, because this position is determined by two shoulders fixed to the housing, that is to say by positive locking.

Durch die in den Unteransprüchen aufgeführten Maßnahmen sind vorteilhafte Weiterbildungen der im Hauptanspruch angegebenen Anordnung möglich.Advantageous developments of the arrangement specified in the main claim are possible through the measures listed in the subclaims.

Besonders vorteilhaft ist es, wenn die Anschlagschulter für die Hohlnadel und deren Gegenschulter nach den Merkmalen des Anspruchs 2 ausgebildet sind. In diesem Fall wird der Lagerspalt zwischen der Hohlnadel und dem Düsenkörper in Schließstellung der Hohlnadel gegen die Brennkammer der Maschine hin abgedeckt, so daß eine einwandfreie Führung der Hohlnadel im Düsenkörper für lange Zeit gewährleistet ist.It when the stop shoulder for the hollow needle and its counter shoulder are designed according to the features of claim 2 is particularly advantageous. In this case, the bearing gap between the hollow needle and the nozzle body is covered in the closed position of the hollow needle against the combustion chamber of the machine, so that proper guidance of the hollow needle in the nozzle body is ensured for a long time.

Ein einfacher und fertigungsgerechter Aufbau der Einspritzdüse ergibt sich mit den Merkmalen der Ansprüche 3 bis 5.A simple and production-oriented construction of the injection nozzle results from the features of claims 3 to 5.

In Weiterbildung der Erfindung kann die Hohlnadel als ein mit dem Düsenkörper zusammenarbeitendes, nach außen öffnendes Schließglied zur Steuerung weiterer Spritzöffnungen ausgebildet sein. Diese Anordnung ist besonders vorteilhaft bei in Abhängigkeit vom Ventilhub querschnittsgesteuerten Loch- und Zapfendüsen. Die Kraftstofführung kann stromab des bzw. der Ventilsitze freizügig gestaltet und insbesondere in mehrere Spritzlöcher bzw. Spritzlochgruppen aufgeteilt werden, deren Querschnitt und Richtung den Erfordernissen des jeweiligen Anwendungsfalles anpaßbar sind.In a further development of the invention, the hollow needle can be designed as a closing member which cooperates with the nozzle body and opens outwards to control further spray openings. This arrangement is particularly advantageous in the case of cross-section-controlled hole and pin nozzles depending on the valve stroke. The fuel guide can be freely designed downstream of the valve seat (s) and in particular divided into several spray holes or spray hole groups, the cross-section and direction of which can be adapted to the requirements of the respective application.

Die Hohlnadel kann gemäß Anspruch 8 mit dem Düsenkörper einen ersten Spritzlochquerschnitt und mit der Ventilnadel einen zweiten Spritzlochquerschnitt steuern. Die Mittel zum Zurückhalten der Ventilnadel gegenüber der sich in Öffnungsrichtung bewegenden Hohlnadel können so angeordnet sein, daß sie unmittelbar nach Beginn der Öffnungsbewegung der Hohlnadel zur Wirkung kommen. In diesem Fall wird zunächst der von Hohlnadel und Ventilnadel gesteuerte Spritzlochquerschnitt geöffnet, während der andere Spritzlochquerschnitt erst nach einem Teilhub der Hohlnadel freigegeben wird.The hollow needle can control a first spray hole cross section with the nozzle body and a second spray hole cross section with the valve needle. The means for retaining the valve needle with respect to the hollow needle moving in the opening direction can be arranged such that they come into effect immediately after the opening movement of the hollow needle begins. In this case, that of Hollow needle and valve needle controlled spray hole cross section opened, while the other spray hole cross section is only released after a partial stroke of the hollow needle.

Die Einspritzfolge kann auch so gesteuert sein, daß die Mittel zum Zurückhalten der Ventilnadel erst nach einem einer Voreinspritzphase entsprechenden ersten Teilhub der Hohlnadel zu Wirkung kommen. Dadurch ist erreicht, daß zunächst der weiter am Rand der Brennkammer angeordnete erste Spritzlochquerschnitt von der Hohlnadel aufgesteuert wird, und daß erst am Beginn der Haupteinspritzphase der zweite, weiter zur Mitte der Brennkammer hin angeordnete Spritzlochquerschnitt durch die Ventilnadel freigegeben wird. Außerdem ist erreicht, daß sich nach Zurücklegen des ersten Teilhubes der Hohlnadel mit der Einspritzmenge auch der Schließdruck und damit der vor den Ventilen anstehende Kraftstoffdruck sprunghaft erhöht, so daß im Teil- und Vollastbereich der Brennkraftmaschine eine einwandfreie Aufbereitung des Kraftstoffs gewährleistet ist.The injection sequence can also be controlled so that the means for retaining the valve needle come into effect only after a first partial stroke of the hollow needle corresponding to a pre-injection phase. It is thereby achieved that the first spray hole cross section, which is arranged further at the edge of the combustion chamber, is opened by the hollow needle, and that the second spray hole cross section, which is arranged further towards the center of the combustion chamber, is only released by the valve needle at the beginning of the main injection phase. It is also achieved that after the first partial stroke of the hollow needle with the injection quantity, the closing pressure and thus the fuel pressure in front of the valves increases suddenly, so that in the partial and full load range of the internal combustion engine a perfect preparation of the fuel is guaranteed.

Bei Ausbildung der Hohlnadel nach den Merkmalen des Anspruchs 10 erhält man bezüglich des zweiten Spritzlochquerschnittes die Funktion einer konventionellen Lochdüse mit nach innen öffnender Ventilnadel, ohne daß man Maßnahmen zur Beseitigung von Lecköl treffen muß.When the hollow needle is designed according to the features of claim 10, the function of a conventional perforated nozzle with an inwardly opening valve needle is obtained with respect to the second spray hole cross section, without taking measures to eliminate leakage oil.

Die Hohlnadel kann zweckmäßig nach den Merkmalen des Anspruchs 11 ausgebildet sein und mehrere, den ersten Spritzlochquerschnitt bildende Spritzlöcher im Düsenkörper steuern.The hollow needle can expediently be designed according to the features of claim 11 and control a plurality of spray holes forming the first spray hole cross section in the nozzle body.

Eine ohne Spritzlöcher im Düsenkörper auskommende Ausführung ergibt sich, wenn gemäß Anspruch 12 der erste Spritzlochquerschnitt durch Querbohrungen in der Hohlnadel gebildet ist, die nach einem Teilhub der Hohlnadel aus der Führungsbohrung des Düsenkörpers austreten.An embodiment without spray holes in the nozzle body is obtained if, according to claim 12, the first spray hole cross section is formed by transverse bores in the hollow needle, which emerge from the guide bore of the nozzle body after a partial stroke of the hollow needle.

Bei einer nach Anspruch 13 ausgebildeten Einspritzdüse werden in Schließstellung der Hohlnadel die Verbrennungsgase auch vom festen Ventilsitz am Düsenkörper abgehalten.In an injection nozzle designed according to claim 13, in the closed position of the hollow needle, the combustion gases are also prevented from the fixed valve seat on the nozzle body.

Zeichnungdrawing

Vier Ausführungsbeispiele der Erfindung sind in der Zeichnung dargestellt und in der nachfolgenden Beschreibung näher erläutert. Die Figuren 1 bis 4 zeigen je einen Teilschnitt durch eines der Ausführungsbeispiele.Four embodiments of the invention are shown in the drawing and explained in more detail in the following description. Figures 1 to 4 each show a partial section through one of the exemplary embodiments.

Beschreibung der AusführungsbeispieleDescription of the embodiments

Die Einspritzdüse nach Figur 1 hat einen Düsenkörper 10, der durch einen Schraubkörper 12 an einem Düsenhalter 14 festgespannt ist. Im Düsenkörper 10 ist eine Führungsbohrung 16 für eine Hohlnadel 18 und eine im Durchmesser größere Bohrung 20 gebildet, welche an einer Schulter 22 in die Führungsbohrung 16 übergeht. In die Bohrung 20 ragt ein Ansatz 24 des Düsenhalters 14 passend hinein, der mit einer Bohrung 26 und am Stirnende mit einer kleineren Öffnung 28 versehen ist, deren Querschnitt zwei Flächen aufweist. Dadurch ist eine vom einspritzseitigen Ende der Düse abgekehrte, gehäusefeste Schulter 30 mit umlaufender Auflagefläche gebildet.The injection nozzle according to FIG. 1 has a nozzle body 10 which is clamped to a nozzle holder 14 by a screw body 12. A guide bore 16 for a hollow needle 18 and a bore 20 of larger diameter is formed in the nozzle body 10 and merges into the guide bore 16 on a shoulder 22. A projection 24 of the nozzle holder 14 protrudes into the bore 20, which is provided with a bore 26 and at the front end with a smaller opening 28, the cross section of which has two surfaces. As a result, a shoulder 30 fixed to the housing and having a circumferential contact surface is turned away from the injection-side end of the nozzle.

Die Hohlnadel 18 hat eine von ihrer oberen Stirnseite 32 ausgehende Längsbohrung 36, die bis zu einem konischen Ventilsitz 38 führt, an welchem sich stromab ein Sackloch 40 mit nach außen führenden Spritzlöchern 41, 42 in dem als Kuppe 43 ausgebildeten Stirnende der Hohlnadel 18 anschließt.The hollow needle 18 has a longitudinal bore 36 extending from its upper end face 32, which leads to a conical valve seat 38, which is followed downstream by a blind hole 40 with spray holes 41, 42 leading to the outside in the front end of the hollow needle 18 designed as a tip 43.

Die Hohlnadel 18 ist mit einem im Außendurchmesser leicht geschwächten Abschnitt 48 versehen, der in der Nähe seines Übergangs zu einem ungeschwächten, im Düsenkörper 10 geführten Abschnitt 50 eine Querbohrung 52 hat. An den Abschnitt 48 schließt sich oben ein mit zwei Flächen versehener Kopf 54 an, der mit dem erforderlichen Bewegungsspiel passend in die Öffnung 28 ragt und die Hohlnadel 18 gegen Verdrehen sichert.The hollow needle 18 is provided with a section 48 which is slightly weakened in the outer diameter and which, in the vicinity of its transition to an un weakened section 50 guided in the nozzle body 10, has a transverse bore 52. The section 48 is followed at the top by a head 54 provided with two surfaces, which, with the required play, protrudes into the opening 28 and secures the hollow needle 18 against rotation.

Am Außenumfang der Hohlnadel 18 ist ferner in der Nähe des Ventilsitzes'38 eine konische Ringschulter 56 gebildet, welche mit einer entsprechend geformten Gegenschulter 58 am Stirnende des Düsenkörpers 10 zusammenarbeitet. In der Bohrung 20 ist eine Schließfeder 60 angeordnet, die sich unten an einem auf der Schulter 22 aufliegenden Flansch 62 einer Buchse 64 abstützt, die den Abschnitt 48 der Hohlnadel 18 mit Spiel umgibt. Am oberen Ende greift die Schließfeder 60 an einem Druckring 66 an, der gegen eine zwischen dem Abschnitt 48 und dem Kopf 54.gebildete Ringschulter 68 der Hohlnadel 18 stößt. Der durch die Schließfeder 60 hervor-. gerufene Aufwärtshub (Schließhub) der Hohlnadel 18 wird durch die Schultern 56 und 58 an Hohlnadel 18 und Düsenkörper 10 begrenzt, die als Ventilflächen ausgebildet sind und in Schließstellung der Hohlnadel 18 den Lagerspalt zwischen dieser und dem Düsenkörper 10 gegen die Brennkammer hin abdichten.On the outer circumference of the hollow needle 18, a conical annular shoulder 56 is further formed in the vicinity of the valve seat 38, which cooperates with a correspondingly shaped counter shoulder 58 at the front end of the nozzle body 10. A closing spring 60 is arranged in the bore 20, which is supported at the bottom on a flange 62 of a bush 64 resting on the shoulder 22, which surrounds the section 48 of the hollow needle 18 with play. At the upper end, the closing spring 60 engages a pressure ring 66 which abuts an annular shoulder 68 of the hollow needle 18 formed between the section 48 and the head 54. The highlighted by the closing spring 60. Called upward stroke (closing stroke) of the hollow needle 18 is limited by the shoulders 56 and 58 to the hollow needle 18 and nozzle body 10, which are designed as valve surfaces and seal the bearing gap between the latter and the nozzle body 10 against the combustion chamber in the closed position of the hollow needle 18.

In der Längsbohrung 36 der Hohlnadel 18 ist eine Ventilnadel 70 verschiebbar geführt, die am einspritzseitigen Stirnende einen mit dem Ventilsitz 38 zusammenarbeitenden Dichtkegel 72 hat. Der Dichtkegel 72 ist an einem im Durchmesser etwas geschwächten Abschnitt 74 der Ventilnadel 70 gebildet, der an einer Schulter 76 in den ungeschwächten Abschnitt der Ventilnadel 70 übergeht. Die Schulter 76 liegt etwas oberhalb der Querbohrung 52 in der Hohlnadel 18, so daß der zwischen dem Abschnitt 74 der Ventilnadel 70 und der Wand der Längsbohrung 36 in der Hohlnadel 18 gebildete Ringraum 78 über die Querbohrung 52, das Ringspiel zwischen Hohlnadel 18 und Buchse 64, sowie über eine oder mehrere Querbohrungen 80 in der Buchse 64 mit der Bohrung 20 im Düsenkörper 10 in Verbindung steht.A valve needle 70 is slidably guided in the longitudinal bore 36 of the hollow needle 18 and has a sealing cone 72 which cooperates with the valve seat 38 at the end on the injection side. The sealing cone 72 is formed on a section 74 of the valve needle 70 which is somewhat weakened in diameter and which merges on a shoulder 76 into the unattenuated section of the valve needle 70. The shoulder 76 lies somewhat above the transverse bore 52 in the hollow needle 18, so that the annular space 78 formed between the section 74 of the valve needle 70 and the wall of the longitudinal bore 36 in the hollow needle 18 via the transverse bore 52, the annular play between the hollow needle 18 and the bushing 64 , and via one or more transverse bores 80 in the bushing 64 is connected to the bore 20 in the nozzle body 10.

Die Ventilnadel 70 ragt oben ein Stück weit aus der Hohlnadel 18 heraus und ist dort mit einem Ringbund 82 versehen, an dessen oberer Stirnseite eine Ventilfeder 84 angreift, welche sich an einer in die Bohrung 26 eingeschraubten Gewindebuchse 86 abstützt. Die Ventilfeder 84 ist bestrebt, die Ventilnadel 70 gegen den Ventilsitz 38 in der Hohlnadel 18 zu drücken. Das gelingt in der in der Zeichnung dargestellten Schließlage der Hohlnadel 18, in welcher der Bund 82 der Ventilnadel 70 noch um den Hub h1 von der Schulter 30 am Düsenhalter 14 entfernt ist. Wenn die Hohlnadel 18 in Öffnungsrichtung den Weg h1 zurückgelegt hat, liegt der Bund 82 an der Schulter 30 an, wonach die Ventilnadel 70 an einer weiteren Mitbewegung mit der Hohlnadel 18 gehindert ist. Der Gesamthub h2 der Hohlnadel 18 ist begrenzt durch die Buchse 64, an deren oberer Stirnseite der Druckring 66 zur Anlage kommt.The valve needle 70 protrudes a bit from the hollow needle 18 at the top and is provided there with an annular collar 82, on the upper end face of which a valve spring 84 engages, which is supported on a threaded bushing 86 screwed into the bore 26. The valve spring 84 endeavors to press the valve needle 70 against the valve seat 38 in the hollow needle 18. This is achieved in the closed position of the hollow needle 18 shown in the drawing, in which the collar 82 of the valve needle 70 is still removed from the shoulder 30 on the nozzle holder 14 by the stroke h 1 . When the hollow needle 18 has traveled the path h 1 in the opening direction, the collar 82 lies against the shoulder 30, after which the valve needle 70 is prevented from moving along with the hollow needle 18. The total stroke h 2 of the hollow needle 18 is limited by the bushing 64, on the upper end of which the pressure ring 66 comes to rest.

Die Gewindebuchse 86 ist mit einer Bohrung 88 zum Zuführen des Kraftstoffs versehen. Der Kraftstoffweg führt danach über die Bohrung 26 und eine die Schulter 30 umgehende Randaussparung 90 im Ansatz 24 des Düsenhalters 14 in die Bohrung 20, wo der Kraftstoff auf die Stirnseite 32 der Hohlnadel 18 einwirkt und auf diese eine der Schließfeder 60 entgegenwirkende Kraft in Richtung zur Brennkammer hin ausübt. Aus der Bohrung 20 gelangt der Kraftstoff über die Querbohrung 52 in der Hohlnadel 18 in den Ringraum 78 zwischen Hohlnadel 18 und Ventilnadel 70 und übt dort über die schmale Ringfläche 92 oberhalb des Ventilsitzes 38 eine weitere Kraft auf die Hohlnadel 18 aus. Der Kraftstoff übt ferner auch auf die Ventilnadel 70 eine nach unten wirkende resultierende Kraft aus, welche unterstützend zur Ventilfeder 84 d.ie Ventilnadel 70 an den Ventilsitz 38 drückt.The threaded bushing 86 is provided with a bore 88 for supplying the fuel. The fuel path then leads via the bore 26 and an edge recess 90 surrounding the shoulder 30 in the neck 24 of the nozzle holder 14 into the bore 20, where the fuel acts on the end face 32 of the hollow needle 18 and on this force opposing the closing spring 60 in the direction of Combustion chamber. From the bore 20, the fuel passes through the transverse bore 52 in the hollow needle 18 into the annular space 78 between the hollow needle 18 and the valve needle 70 and exerts a further force on the hollow needle 18 via the narrow annular surface 92 above the valve seat 38. The fuel also exerts a downward-acting resulting force on the valve needle 70 which, in support of the valve spring 84, presses the valve needle 70 against the valve seat 38.

Beim Anstieg des Kraftstoffdrucks zu Beginn eines Einspritzhubes wird unter Zusammendrücken der Schließfeder 60 die Hohlnadel nach unten aus dem Düsenkörper 10 herausbewegt. Dieser Bewegung kann die Ventilnadel 70 unter dem Einfluß der Ventilfeder 84 und des Kraftstoffdrucks nur um das kleine Wegstück h1 folgen, wonach der Bund 82 an der Schulter 30 anschlägt und eine Relativbewegung der Ventilnadel 70 gegenüber der sich weiterbewegenden Hohlnadel 18 erzwingt. Diese Relativbewegung hat in bezug auf die Kraftstoffsteuerung im Ausspritzbereich etwa die gleiche Wirkung wie eine sich nach innen bewegende Ventilnadel bei feststehendem Ventilsitz. Gegenüber Einspritzdüsen mit einer derartigen Arbeitsweise (I-Düsen) hat die beschriebene Anordnung jedoch den Vorteil, daß ein Leckölstrom in der Führung der Ventilnadel 70 oder der Hohlnadel 18 nicht störend ist bzw. nicht auftritt und daher keine Mittel zu dessen Abführung vorgesehen werden müssen.When the fuel pressure rises at the beginning of an injection stroke, the hollow needle is moved downward out of the nozzle body 10 by compressing the closing spring 60. Under the influence of the valve spring 84 and the fuel pressure, the valve needle 70 can only follow this movement by the small distance h 1 , after which the collar 82 strikes the shoulder 30 and forces a relative movement of the valve needle 70 with respect to the hollow needle 18 which is moving further. This relative movement has approximately the same effect in relation to the fuel control in the injection region as an inwardly moving valve needle with a fixed valve seat. Compared to injection nozzles with such a mode of operation (I-nozzles), however, the arrangement described has the advantage that a leakage oil flow in the guide of the valve needle 70 or the hollow needle 18 is not disruptive or does not occur and therefore no means for its removal need to be provided.

Bei Abfall des Kraftstoffdrucks am Ende eines Einspritzhubes führt die Schließfeder 60 die Hohlnadel 18 in die Ausgangsstellung zurück, in der sie mit ihrer Schulter 56 an der Schulter 58 des Düsenkörpers 10 anschlägt. Die beiden Schultern 56 und 58 bilden danach einen ventilartigen Verschluß, welcher den Verbrennungsgasen den Zutritt zum Lagerspalt zwischen Hohlnadel 18 und Düsenkörper 10 verwehrt. Kurz vor dem Aufsetzen der Schulter 56 auf die Schulter 58 trifft die Ventilnadel 70 auf den Ventilsitz 38 auf, wonach der Kraftstoffaustritt aus dem Spritzlöchern 41, 42 unterbrochen ist. Die Ventilnadel 70 hebt danach noch um den Hub h1 von der Schulter 30 ab. Der Hub h1 ist mit Rücksicht auf die in der Fertigung zuzulassenden Toleranzen gerade so groß bemessen, daß sich die Ventilnadel 70 in der Schließstellung der Hohlnadel 18 mit Sicherheit auf den Ventilsitz 38 auflegen kann.When the fuel pressure drops at the end of an injection stroke, the closing spring 60 returns the hollow needle 18 to the starting position, in which it strikes with its shoulder 56 on the shoulder 58 of the nozzle body 10. The two shoulders 56 and 58 then form a valve-like closure which prevents the combustion gases from accessing the bearing gap between the hollow needle 18 and the nozzle body 10. Shortly before the shoulder 56 is placed on the shoulder 58, the valve needle 70 hits the valve seat 38, after which the fuel discharge from the spray holes 41, 42 is interrupted. The valve needle 70 then lifts from the shoulder 30 by the stroke h 1 . The stroke h 1 is dimensioned just so large in view of the tolerances to be permitted in production that the valve needle 70 can rest safely on the valve seat 38 in the closed position of the hollow needle 18.

Das Ausführungsbeispiel nach Figur 2 stimmt mit jenem nach Figur 1 in den bisher beschriebenen Einzelheiten bis auf die Besonderheiten überein, daß die Hohlnadel 18 selbst das Schließglied für eine Ventileinrichtung bildet, welche eine zweite Gruppe von Spritzlöchern 94 und 96 steuert, die im Düsenkörper 10 verlaufen. Die Hohlnadel 18 ist zu diesem Zweck mit einer Querbohrung 98 und einer Ringnut 100 im Mantelumfang versehen, in welche die Querbohrung 98 an beiden Enden ausmündet. Der Bund 82 der Ventilnadel 70 ist hier von der gehäusefesten Schulter 30 um den Teilhub h1 entfernt, der nun nicht mehr nur zur Ausschaltung von Fertigungstoleranzen, sondern auch zur hubabhängigen Steuerung der beiden Gruppen 41, 42 und 94, 96 der Spritzlöcher dient.The exemplary embodiment according to FIG. 2 corresponds to that according to FIG. 1 in the details described so far, except that the hollow needle 18 itself forms the closing member for a valve device which controls a second group of spray holes 94 and 96 which run in the nozzle body 10 . For this purpose, the hollow needle 18 is provided with a transverse bore 98 and an annular groove 100 in the circumference of the jacket, into which the transverse bore 98 opens at both ends. The collar 82 of the valve needle 70 is here removed from the shoulder 30 fixed to the housing by the partial stroke h 1 , which is now used not only to eliminate manufacturing tolerances but also to control the two groups 41, 42 and 94, 96 of the spray holes as a function of the stroke.

Beim Öffnungshub der Hohlnadel 18 werden zunächst über die Ringnut 100 die in ihrer Gesamtheit einen ersten Spritzlochquerschnitt I ergebenden Spritzlöcher 94 und 96 aufgesteuert, wobei die Ventilfeder 84 die Ventilnadel 70 am Ventilsitz 38 der Hohlnadel 18 angelegt hält. Im weiteren Verlauf des Öffnungshubes der Hohlnadel 18 wird die Ventilnadel 70 gegenüber dieser zurückgehalten, wodurch auch die in ihrer Gesamtheit einen zweiten Spritzlochquerschnitt II ergebenden Spritzlöcher 41, 42 aufgesteuert werden. Am Ende des Einspritzvorganges spielen sich die beschriebenen Vorgänge in der umgekehrten Reihenfolge ab. Die Anordnung könnte durch entsprechende Wahl des Abstandes der Querbohrung 98 vom Dichtkegel 72 an der Ventilnadel 70 auch so getroffen sein, daß zuerst der Dichtkegel 72 vom Ventilsitz 38 abhebt und erst danach die zweite Gruppe 94, 96 der Spritzlöcher aufgesteuert wird.During the opening stroke of the hollow needle 18, the spray holes 94, which in their entirety result in a first spray hole cross section I, are first produced via the annular groove 100 and opened 96, the valve spring 84 holding the valve needle 70 against the valve seat 38 of the hollow needle 18. During the further course of the opening stroke of the hollow needle 18, the valve needle 70 is retained relative to the latter, as a result of which the spray holes 41, 42, which in their entirety result in a second spray hole cross section II, are opened. At the end of the injection process, the processes described take place in the reverse order. The arrangement could also be made by appropriate selection of the distance of the transverse bore 98 from the sealing cone 72 on the valve needle 70 so that first the sealing cone 72 lifts off the valve seat 38 and only then is the second group 94, 96 of the spray holes opened.

Die Einspritzdüse nach Figur 2 hat auch den Vorteil, daß beim Aufsteuern der Spritzlöcher 41, 42 bzw. des zweiten Spritzlochquerschnitts II und der damit verbundenen sprunghaften Vergrößerung des Spritzloch-Gesamtquerschnittes ein Drucksprung in der Schließkraft auftritt, der durch das Abfangen der Kraft der Ventilfeder 84 hervorgerufen ist und vorteilhaft dafür sorgt, daß danach der Kraftstoff gleich gut wie beim ersten Teilhub h1 aufbereitet und zerstäubt wird.The injection nozzle according to FIG. 2 also has the advantage that when opening the spray holes 41, 42 or the second spray hole cross section II and the associated sudden increase in the overall spray hole cross section, a pressure jump occurs in the closing force, which occurs due to the interception of the force of the valve spring 84 is caused and advantageously ensures that the fuel is then processed and atomized as well as in the first partial stroke h 1 .

Das Ausführungsbeispiel nach Figur 3 unterscheidet sich vom vorbeschriebenen lediglich dadurch, daß die Schulter 56 der Hohlnadel 18 stromauf des ersten Spritzlochquerschnittes I angeordnet ist und mit einer inneren Schulter 58 des Düsenkörpers 10 zusammenarbeitet. Bei dieser Ausführung wird in der Schließstellung der Hohlnadel 18 zwar nur der Lagerspalt zwischen Hohlnadel 18 und Düsenkörper 10 gegen die Brennkammer hin abgeschirmt. Vorteilhaft ist jedoch, daß die in der Schließstellung nach Art eines Ventils zusammenwirkenden Schultern 56 und 58 den Ringraum 78 zusätzlich gegen den ersten Spritzlochquerschnitt I dichten.The exemplary embodiment according to FIG. 3 differs from the one described above only in that the shoulder 56 of the hollow needle 18 is arranged upstream of the first spray hole cross section I and cooperates with an inner shoulder 58 of the nozzle body 10. In this embodiment, only the bearing gap between the hollow needle 18 and the nozzle body 10 is shielded from the combustion chamber in the closed position of the hollow needle 18. It is advantageous however, that the shoulders 56 and 58, which cooperate in the closed position like a valve, additionally seal the annular space 78 against the first spray hole cross section I.

Wenn auf den zusätzlichen Vorteil des Drucksprungs nach dem vorgesehenen ersten Teilhub der Hohlnadel 18 verzichtet wird, kann die Spritzfolge bezüglich der Spritzlochquerschnitte I und II auch umgekehrt werden.If the additional advantage of the pressure jump after the intended first partial stroke of the hollow needle 18 is dispensed with, the spray sequence can also be reversed with regard to the spray hole cross sections I and II.

Das Ausführungsbeispiel nach Figur 4 ist eine weitere Abwandlung des Ausführungsbeispiels nach Figur 2. Der Spritzlochquerschnitt I ist hier durch Spritzlöcher 110 und 112 in der Hohlnadel 18 gebildet, die in Schließstellung der Hohlnadel 18 durch eine Überdeckung 114 und durch den zwischen den Schultern 56 und 58 an Hohlnadel 18 und Düsenkörper 10 gebildeten Ventilsitz gegen die Brennkammer hin abgedichtet sind. Beim Bewegen der Hohlnadel 18 in Öffnungsrichtung treten die Spritzlöcher 110'und 112 aus der Führungsbohrung im Düsenkörper 10 heraus, so daß sich die bei der Einspritzdüse nach Figur 2 vorgesehenen Kanäle 46, 47 im Düsenkörper 10 erübrigen.The exemplary embodiment according to FIG. 4 is a further modification of the exemplary embodiment according to FIG. 2. The spray hole cross section I is formed here by spray holes 110 and 112 in the hollow needle 18, which in the closed position of the hollow needle 18 is covered by an overlap 114 and by that between the shoulders 56 and 58 valve seat formed on the hollow needle 18 and nozzle body 10 are sealed off from the combustion chamber. When the hollow needle 18 is moved in the opening direction, the spray holes 110 ′ and 112 emerge from the guide bore in the nozzle body 10, so that the channels 46, 47 provided in the injection nozzle according to FIG. 2 are unnecessary in the nozzle body 10.

Die Einspritzdüse nach Figur 4 hat ebenfalls den Vorteil, daß der Spritzlochquerschnitt I in der Schließstellung der Hohlnadel 18 durch den zwischen den Schultern 56 und 58 gebildeten Ventilsitz zusätzlich abgedichtet ist. Die Reihenfolge des Aufsteuerns der Spritzlochquerschnitte I und II kann durch Abstimmung von Vorhub h1 und Überdeckung 114 beliebig gewählt werden.The injection nozzle according to FIG. 4 also has the advantage that the spray hole cross-section I is additionally sealed in the closed position of the hollow needle 18 by the valve seat formed between the shoulders 56 and 58. The sequence of opening the spray hole cross sections I and II can be chosen as desired by coordinating the forward stroke h 1 and overlap 114.

Claims (13)

1. Kraftstoff-Einspritzdüse für Brennkraftmaschinen, mit einem vom Druck des Kraftstoffs in dessen Strömungsrichtung entgegen der Kraft einer Schließfeder verschiebbaren Hohlnadel, in welcher ein innerer Ventilsitz gebildet und eine mit dem Ventilsitz zusammenarbeitende Ventilnadel verschiebbar gelagert ist, ferner mit Mitteln zum Zurückhalten der Ventilnadel gegenüber der in Öffnungsrichtung sich bewegenden Hohlnadel zum Zweck des Öffnens des Ventils, sowie mit einer Anschlagschulter für die Hohlnadel zum Abfangen der Schließfederkraft in der Schließstellung des Ventils, dadurch gekennzeichnet, daß die Anschlagschulter (58) für die Hohlnadel (18) an dem die Hohlnadel lagernden Düsenkörper (JO) gebildet ist, daß die Ventilnadel (70) von einer Ventilfeder (84) in Strömungsrichtung des Kraftstoffs beaufschlagt und in Schließstellung der Hohlnadel (18) an den Ventilsitz (38) angedrückt ist, und daß zum Zurückhalten der Ventilnadel (70) gegenüber der in Öffnungsrichtung sich bewegenden Hohlnadel (18) eine zweite gehäusefeste Schulter (30) dient.1. Fuel injection nozzle for internal combustion engines, with a hollow needle displaceable by the pressure of the fuel in its flow direction against the force of a closing spring, in which an inner valve seat is formed and a valve needle cooperating with the valve seat is slidably mounted, furthermore with means for retaining the valve needle opposite the hollow needle moving in the opening direction for the purpose of opening the valve, and with a stop shoulder for the hollow needle to absorb the closing spring force in the closed position of the valve, characterized in that the stop shoulder (58) for the hollow needle (18) on which the hollow needle is mounted Nozzle body (JO) is formed such that the valve needle (70) is acted upon by a valve spring (84) in the flow direction of the fuel and is pressed against the valve seat (38) in the closed position of the hollow needle (18), and that the valve needle (70) is retained to hold it back. opposite the Hoh moving in the opening direction lnadel (18) serves a second housing-fixed shoulder (30). 2. Einspritzdüse nach Anspruch 1, dadurch gekennzeichnet, daß die Anschlagschulter (58) für die Hohlnadel (18) und deren Gegenschulter (56) als Ventilflächen ausgebildet sind, welche in Schließstellung der Hohlnadel (18) deren Lagerspalt zum Düsenkörper (10) dichten bzw. zur Brennkammer hin abschirmen.2. Injection nozzle according to claim 1, characterized in that the stop shoulder (58) for the hollow needle (18) and its counter shoulder (56) are designed as valve surfaces, which in the closed position of the hollow needle (18) seal the bearing gap to the nozzle body (10) or screen towards the combustion chamber. 3. Einspritzdüse nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß der Kraftstoff-Zufuhrkanal durch den Einbauraum (26) für die Ventilfeder (84) hindurchgeführt ist.3. Injection nozzle according to claim 1 or 2, characterized in that the fuel supply channel is passed through the installation space (26) for the valve spring (84). 4. Einspritzdüse nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß der Öffnungshub (h2) der Hohlnadel (18) durch eine die Hohlnadel (18) mit Spiel umgebende und gegenüber der Schließfeder (60) abschirmende Buchse (64) begrenzt ist.4. Injection nozzle according to one of claims 1 to 3, characterized in that the opening stroke (h 2 ) of the hollow needle (18) by a hollow needle (18) with play surrounding and with respect to the closing spring (60) shielding bushing (64) is limited . 5. Einspritzdüse nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß die Ventilnadel (70) an ihrem aus der Hohlnadel (18) herausragenden Endabschnitt einen Ringbund (82) hat, an dessen einer Stirnseite die Ventilfeder (84) angreift und dessen andere Stirnseite die Gegenschulter zu der gehäusefesten Schulter (30) bildet.5. Injection nozzle according to one of claims 1 to 4, characterized in that the valve needle (70) on its from the hollow needle (18) projecting end portion has an annular collar (82), on one end face the valve spring (84) engages and the other Front forms the counter shoulder to the shoulder (30) fixed to the housing. 6. Einspritzdüse nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß die Hohlnadel (18) stromab des Ventilsitzes (38) ein Sackloch (40) hat, von welchem die Spritzlöcher (41, 42) nach außen führen.6. Injection nozzle according to one of claims 1 to 5, characterized in that the hollow needle (18) downstream of the valve seat (38) has a blind hole (40) from which the spray holes (41, 42) lead to the outside. 7. Einspritzdüse nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß die Hohlnadel (18) als ein mit dem Düsenkörper (10) zusammenarbeitendes, nach außen öffnendes Schließglied zur Steuerung weiterer Spritzöffnungen (94, 96 bzw. 110, 112) ausgebildet ist.7. Injection nozzle according to one of claims 1 to 6, characterized in that the hollow needle (18) as a with the nozzle body (10) cooperating, outwardly opening closing member for controlling further spray openings (94, 96 and 110, 112) is formed . 8. Einspritzdüse nach Anspruch 7, dadurch gekennzeichnet, daß die Hohlnadel (18) mit dem Düsenkörper (10) einen ersten Spritzlochquerschnitt (I) und mit der Ventilnadel (70) einen zweiten Spiitzlochquerschnitt (II) steuert.8. Injection nozzle according to claim 7, characterized in that the hollow needle (18) with the nozzle body (10) controls a first spray hole cross section (I) and with the valve needle (70) controls a second tip hole cross section (II). 9. Einspritzdüse nach Anspruch 8, dadurch gekennzeichnet, daß die Mittel (30) zum Zurückhalten der Ventilnadel (70) gegenüber der in Öffnungsrichtung sich bewegenden Hohlnadel (18) zur Wirkung kommen, wenn die Hohlnadel (18) einen einer Voreinspritzphase entsprechenden ersten Teilhub in Öffnungsrichtung zurückgelegt hat.9. Injection nozzle according to claim 8, characterized in that the means (30) for retaining the valve needle (70) with respect to the hollow needle (18) moving in the opening direction come into effect when the hollow needle (18) corresponds to a pre-injection phase corresponding to the first partial stroke Has opened the opening direction. 10. Einspritzdüse nach einem der Ansprüche 7 und 9, dadurch gekennzeichnet, daß die Hohlnadel (18) einen kegeligen Ventilsitz (38) und die Ventilnadel (70) einen Dichtkegel (72) hat, und daß das spritzseitige Stirnende der Hohlnadel (18) nach Art einer Lochdüse als Kuppe (43) ausgebildet ist, in welcher die den zweiten Spritzlochquerschnitt (II) bildenden Spritzlöcher (41, 42) vorgesehen sind.10. Injection nozzle according to one of claims 7 and 9, characterized in that the hollow needle (18) has a conical valve seat (38) and the valve needle (70) has a sealing cone (72), and that the injection-side end of the hollow needle (18) after Kind of a perforated nozzle is designed as a dome (43), in which the spray holes (41, 42) forming the second spray hole cross section (II) are provided. 11. Einspritzdüse nach einem der Ansprüche 7 und 9, dadurch gekennzeichnet, daß ein von der Hohlnadel (18) gesteuerter gehäusefester Ventilsitz durch einen die Hohlnadel dicht führenden Wandabschnitt des Düsenkörpers (10) gebildet ist, in dessen Bereich eine den ersten Spritzlochquerschnitt (I) bildende Gruppe von Spritzlöchern (94, 96) in die Führungsbohrung für die Hohlnadel mündet (Figur 2 und 3).11. Injection nozzle according to one of claims 7 and 9, characterized in that a valve seat which is fixed to the housing and is controlled by the hollow needle (18) is formed by a wall section of the nozzle body (10) tightly leading the hollow needle, in the area of which a first spray hole cross section (I) forming group of spray holes (94, 96) opens into the guide hole for the hollow needle (Figure 2 and 3). 12. Einspritzdüse nach einem der Ansprüche 7 und 9, dadurch gekennzeichnet, daß der erste Spritzlochquerschnitt (I, Figur 4) durch Querbohrungen (110, 112) in der Hohlnadel (18) gebildet ist, die nach einem Teilhub der Hohlnadel (18) aus der Führungsbohrung (16) des Düsenkörpers (10) austreten.12. Injection nozzle according to one of claims 7 and 9, characterized in that the first spray hole cross section (I, Figure 4) is formed by transverse bores (110, 112) in the hollow needle (18), which after a partial stroke of the hollow needle (18) emerge from the guide bore (16) of the nozzle body (10). 13. Einspritzdüse nach Anspruch 2 und einem der Ansprüche 8 bis 12, dadurch gekennzeichnet, daß die Anschlagschultern (56, 58) an der Hohlnadel (18) und dem Düsenkörper (10) stromab der Mündung des ersten Spritzlochquerschnitts (I) angeordnet sind.13. Injection nozzle according to claim 2 and one of claims 8 to 12, characterized in that the stop shoulders (56, 58) on the hollow needle (18) and the nozzle body (10) are arranged downstream of the mouth of the first spray hole cross section (I).
EP82104180A 1981-05-20 1982-05-13 Fuel injection nozzle for internal-combustion engines Expired EP0065282B1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE3120044 1981-05-20
DE19813120044 DE3120044A1 (en) 1981-05-20 1981-05-20 Fuel injection nozzle for internal combustion engines
DE3130621 1981-08-01
DE19813130621 DE3130621A1 (en) 1981-08-01 1981-08-01 Fuel injection nozzle for internal combustion engines

Publications (2)

Publication Number Publication Date
EP0065282A1 true EP0065282A1 (en) 1982-11-24
EP0065282B1 EP0065282B1 (en) 1985-10-09

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US (1) US4526323A (en)
EP (1) EP0065282B1 (en)
DE (1) DE3266767D1 (en)

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US5199647A (en) * 1990-12-21 1993-04-06 Zexel Corporation Fuel injection nozzle
EP1087129A3 (en) * 1999-09-23 2003-04-16 Delphi Technologies, Inc. Fuel injector
CN110023616A (en) * 2016-11-30 2019-07-16 日立汽车系统株式会社 Fuel injection device
CN113775433A (en) * 2020-06-10 2021-12-10 上海汽车集团股份有限公司 Engine combustion system

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WO1988008081A1 (en) * 1987-04-07 1988-10-20 Kabushiki Kaisha Komatsu Seisakusho Internal combustion engine
JPH09177640A (en) * 1995-12-15 1997-07-11 Caterpillar Inc Combustion exhaust emission control system by fuel injector having high suck capacity and its method
US6000638A (en) * 1997-11-03 1999-12-14 Caterpillar Inc. Apparatus for strengthening a fuel injector tip member
GB9903496D0 (en) * 1999-02-16 1999-04-07 Lucas Ind Plc Fuel injector
GB9905231D0 (en) * 1999-03-09 1999-04-28 Lucas Ind Plc Fuel injector
US6173913B1 (en) 1999-08-25 2001-01-16 Caterpillar Inc. Ceramic check for a fuel injector
GB0021296D0 (en) * 2000-08-30 2000-10-18 Ricardo Consulting Eng A dual mode fuel injector
AU2002232714A1 (en) 2000-10-24 2002-05-06 Trexel, Inc. Valve for injection molding
US6886762B2 (en) * 2001-12-20 2005-05-03 Caterpillar Inc. Nozzle insert for dual mode fuel injector
US6843434B2 (en) * 2003-02-28 2005-01-18 Caterpillar Inc Dual mode fuel injector with one piece needle valve member
US7032566B2 (en) * 2003-05-30 2006-04-25 Caterpillar Inc. Fuel injector nozzle for an internal combustion engine
CN101307741B (en) * 2008-07-01 2010-06-16 浙江大学 Engine fuel cylinder inner direct ejection device
EP3122468B1 (en) * 2014-03-28 2022-06-22 Deyang Hou A fuel injector flexible for single and dual fuel injection

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Cited By (4)

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Publication number Priority date Publication date Assignee Title
US5199647A (en) * 1990-12-21 1993-04-06 Zexel Corporation Fuel injection nozzle
EP1087129A3 (en) * 1999-09-23 2003-04-16 Delphi Technologies, Inc. Fuel injector
CN110023616A (en) * 2016-11-30 2019-07-16 日立汽车系统株式会社 Fuel injection device
CN113775433A (en) * 2020-06-10 2021-12-10 上海汽车集团股份有限公司 Engine combustion system

Also Published As

Publication number Publication date
DE3266767D1 (en) 1985-11-14
EP0065282B1 (en) 1985-10-09
US4526323A (en) 1985-07-02

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