EP0090296B1 - Needle-valve injection nozzle - Google Patents

Needle-valve injection nozzle Download PDF

Info

Publication number
EP0090296B1
EP0090296B1 EP83102731A EP83102731A EP0090296B1 EP 0090296 B1 EP0090296 B1 EP 0090296B1 EP 83102731 A EP83102731 A EP 83102731A EP 83102731 A EP83102731 A EP 83102731A EP 0090296 B1 EP0090296 B1 EP 0090296B1
Authority
EP
European Patent Office
Prior art keywords
fuel
pressure
piston
needle
needle piston
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.)
Expired
Application number
EP83102731A
Other languages
German (de)
French (fr)
Other versions
EP0090296A1 (en
Inventor
Richard Felix Sharp
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.)
Deere and Co
Original Assignee
Deere and Co
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
Application filed by Deere and Co filed Critical Deere and Co
Priority to AT83102731T priority Critical patent/ATE21437T1/en
Publication of EP0090296A1 publication Critical patent/EP0090296A1/en
Application granted granted Critical
Publication of EP0090296B1 publication Critical patent/EP0090296B1/en
Expired legal-status Critical Current

Links

Images

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
    • F02M61/20—Closing valves mechanically, e.g. arrangements of springs or weights or permanent magnets; Damping of valve lift
    • F02M61/205—Means specially adapted for varying the spring tension or assisting the spring force to close the injection-valve, e.g. with damping of valve lift

Definitions

  • the invention relates to a fuel injector with a needle piston arranged in a first cylinder chamber, which is provided with a valve needle for opening and closing an injection opening and which from a valve closing position by the injection pressure under tension of a spring by an amount corresponding to the opening travel into an Valve opening position is displaceable, with a control piston which is arranged displaceably in a second cylinder chamber and which, when the needle piston is in the valve closed position, is in the end position remote from the needle piston, which is supported against the spring and which leads to a fuel channel leading to the first cylinder chamber in the area between the needle piston and the valve opening controls, with the fuel channel being connected to a fuel pressure source in the end position remote from the needle piston, and which, when the valve is in the open position to initiate the valve closing movement, the spring during its adjustment movement in the direction of the Na delkolben spans by a further amount and thereby separates the fuel channel from the fuel pressure source.
  • the needle piston opens twice per work cycle, first for a pilot injection and then for a main injection.
  • GB-A-529 141 also discloses an injector with which two injections are achieved in one cycle.
  • two pistons lying next to each other are provided.
  • a piston is acted upon at one end by the system pressure and at the other end by a spring, the system pressure being used to move the piston downwards and the spring to move the piston upwards. The upward movement of the piston and thus the closing of the outlets by the needle piston occurs very slowly.
  • DE-A-2 704 688 shows an injection nozzle for quick or abrupt termination of the fuel injection process.
  • a needle piston is provided which has at its upper end a piston which is displaceable in a pressure chamber and which is loaded by a spring in the direction of the closed position.
  • the pressure chamber is connected to a pressure storage device, which comes into effect when the pressure in the supply line drops.
  • the piston is additionally acted upon, so that the needle piston is returned to its closed position under the action of the spring and the pressure from the pressure storage device.
  • FR-A-2 336 563 shows two pressure sources and pumps.
  • the object to be achieved with the invention is seen in designing the fuel injector in such a way that the closing pressure is greater than the opening pressure while maintaining a rapid tearing off of the injection process.
  • control piston is acted upon on the side remote from the needle piston by a second pressure source, a control pressure source and on the side near the needle piston by the first, the fuel pressure source, and in that the pressure of the fuel pressure source and the pressure of the control pressure source for introduction and implementation of the valve opening and closing movement are controllable, the second cylinder space being connectable to a collecting container in its section which can be acted upon by the control pressure for pressure relief.
  • the needle piston and the control piston will be in an unloaded state, ie if the engine has not yet been started, in their starting positions, in which the needle piston is in its valve-closed position and the control piston is in its opposite or distant end position from the needle piston .
  • the nozzle and thus the needle piston are acted upon, pressure builds up in the nozzle, which finally lifts the needle piston from its seat and displaces it against the action of the spring, which is thereby compressed.
  • the displacement by the injection pressure lasts until the maximum injection pressure is reached - in this state, the needle piston will assume a kind of floating position - or until the needle piston leads against a stop.
  • the control piston must now be actuated to close the needle piston.
  • the time of the shift is made dependent on various parameters of the internal combustion engine, and the amount of fuel to be injected can be precisely determined depending on the selection of the closing time.
  • the spring - this time from the opposite side - is compressed by a further amount.
  • the opening pressure does not have to be reached immediately, but possibly with a time delay.
  • the spring will move the needle piston back into its valve closing position. Then the control piston can be relieved and the spring pushes it back into its starting position. in the seen as a whole, the spring for closing the needle piston is additionally tensioned, so that ultimately there is a closing pressure which is above the opening pressure.
  • a channel is provided in the control piston, which connects the fuel channel with another channel leading to the fuel pressure source in its end position remote from the needle piston.
  • the channel designed according to the invention as an annular channel in the control piston is gradually interrupted when it is acted upon, so that the connection to the fuel channel guiding the fuel to the needle piston, so that the fuel flow is initially throttled and then completely prevented.
  • the injection pressure remains so high that the needle piston remains in its open position.
  • valve opening position of the needle piston is limited by a retaining ring means that the injection pressure can be relatively high and the needle piston closes with a time delay when the control piston is acted on.
  • the second cylinder chamber is provided with a relief opening which is opened from the side of the control piston remote from the needle piston when or after the connection of the fuel channel to the fuel pressure source is interrupted.
  • a fuel injection nozzle is designated by 10, its nozzle body by 12, and a nozzle tip provided at one end of the nozzle body by 14.
  • the nozzle body 12 can be screwed into a cylinder head of an internal combustion engine, which is not shown for the sake of simplicity, in such a way that its nozzle tip 14 is connected to a combustion chamber.
  • Fuel is injected into this combustion chamber in a fine veil, for which purpose a few injection openings 18 are provided in the nozzle syringe 14.
  • a control pressure source 20 and a fuel pressure source 22 are first provided in the nozzle body 12 of the fuel injection nozzle 10, each of which is connected to a collecting container 24 and 28 and a separate pump 26 and 30.
  • the control and fuel pressure sources 20, 22 can be designed as a liquid supply chamber with variable pressure and correspond to the control and metering chamber, as is already the case with some injection nozzles.
  • the control space serves to control the injection timing and the metering space to determine the injection quantity.
  • a control device 32 is also inserted in the nozzle body 12, which regulates the fuel flow through the fuel injection nozzle 10.
  • first and a second cylinder space 36 and 34 which are axially aligned with one another in the nozzle body such that the first cylinder space 36 comes to lie in the immediate vicinity of the nozzle tip 14.
  • the cylinder spaces thus lie between the pressure sources to which they are connected, as well as to one another, and the nozzle tip, their upper and lower ends being denoted by 38, 40 and 42, 44.
  • the upper end 38 of the cylinder space 34 is connected to the control pressure source 20 via a first channel 46 and its lower end 40 as well as a point 50 which is approximately midway between the upper and lower ends 38 and 40 is connected to the fuel pressure source 22 via a second line 48.
  • a fuel channel 52 connects the second cylinder space 34 approximately in the area of the point 50 to the lower end 44 or end area of the first cylinder space 36.
  • a relief channel or a relief opening 54 in turn connects the second cylinder space 34 to a collecting container 56 in the area of its upper end 38 , which can be connected to the collecting container 24 and / or 28.
  • a relief valve can also be provided in the first channel 46 and the collection containers could also be integrated in the injection nozzle.
  • the control device is also equipped with a first valve, a control piston 58, which is displaceable in the cylinder space 34 and bears against a rod 60.
  • the latter extends into the first cylinder space 36 and is connected there to a transverse part 62, such as a pin.
  • a channel 64 or an annular groove is machined into the control piston, so that two piston pieces are formed, between which a connection of the channel 48 to the fuel channel 52 is created, provided the control piston 58 is in its position in FIG. 1 or 2 shown top position.
  • the control piston 58 is displaceable between its end positions, that is to say between its uppermost position shown in FIGS. 1 and 2 and its lowest position shown in FIG. 4 by pressure differences which are created in the pressure sources 20 and 22.
  • a second valve a needle piston 66 with step pressure surfaces, is provided in the first cylinder space 36 and can be moved between an open and a closed position. In this, fuel can escape through the nozzle tip 14 once or the leakage of fuel is prevented.
  • the upper surface of the needle piston 66 is designated 68, an interface 70 and a conical base 72. The latter sits on a stiz 73 when the needle piston 66 is in its closed position. In this position, the area exposed to the fuel is smaller than the upper surface 68 because the fuel can only affect the intermediate surface 70. However, if the needle piston 66 is in its open or upper position, the fuel can act on the base surface 72 in addition to the intermediate surface 70.
  • the needle piston 66 is displaced between its open and closed positions by the movement of the control piston 58 and the fuel pressure which, as stated, can act on the intermediate surface and additionally on the base surface. This double actuation enables the control device 32 to react to a drop in pressure on the channel 64 at a point in time at which a drop in pressure has not yet been determined in the first cylinder space 36. This has the effect that the needle piston 66 is already pressed into its closed position before it was able to determine a pressure drop in the first cylinder space 36.
  • first cylinder space 36 there is also a spring 74 between the upper surface 68 of the needle piston 66 and the transverse part 62, which serves to push the control piston 58 and the needle piston 66 away from one another.
  • the upward movement of the needle piston is limited by a retaining ring 76, which is also arranged in the first cylinder space.
  • FIG. 2 shows the starting position in which there is no pressure difference in the pressure sources 20 and 22 and the pressure influences the movement of the control device 32.
  • the control piston 58 In this position, the control piston 58 is in its uppermost position and fuel can pass through the channel 64 from the channel 48 into the fuel channel 52 into the needle piston 66, which is then still in its closed position, in which the base surface 72 Seat 73 closes.
  • the spring 74 In this position, the spring 74 is slightly compressed, whereby the control piston 58 and the needle piston 66 are pressed away from each other.
  • the fuel pressure in the two pressure sources 20 and 22 is then increased via the pumps 26 and 30 to a predetermined value, which then acts on the intermediate surface 70 and balances the force of the spring.
  • a pressure difference is then generated in the pressure sources 20 and 22, the pressure in the fuel pressure source 22 being lower, so that the control piston 58 moves downward in the direction of its second position.
  • FIG. 3 from which it can be seen that the channel 64 is no longer aligned with the channels 48 and 52 or with the location 50.
  • the fuel flow between the channels 48 and 52 is initially throttled and later completely prevented.
  • the spring 74 is further compressed during this downward movement, since the transverse part 62 then acts on the spring as a result of the rod 60 resting against the control piston.
  • the spring 74 is compressed until its spring force corresponds to the difference in the pressures which act on the upper side of the control piston 58 and on the intermediate surface 70 and base surface 72 of the needle piston 66. At about such a time, particularly when the pressure continues to rise, the spring 74 acts as a mechanical rod and causes the needle piston 66 to move downward is directly dependent on the downward movement of the control piston. Immediately before the fuel connection via the channel 64 is completely interrupted due to the downward movement of the control piston 58, the force of the spring will correspond to the pressure difference that prevails between the pressure sources 20 and 22. The needle piston 66 will then begin its downward movement again.
  • the pressure at the intermediate surface 70 and the base surface 72 begins to decrease.
  • the pressure drop is based on two factors, namely that a part of the fuel will emerge through the nozzle tip and on the other hand the fuel flow from the fuel pressure source 22 is throttled or completely prevented.
  • the pressure in the fuel source will drop until the needle piston 66 is again in its closed position, in which no more fuel can escape through the nozzle tip. Since in this process the pressure force of the spring 74 is higher than during the upward movement of the needle piston 66 and the pressure below the needle piston 66 constantly decreases, the needle piston 66 will close very quickly.
  • the force required to close the needle piston 66 is greater than the force required to open the needle piston. This feature ensures that the fuel flow through the nozzle tip in the combustion chamber of the internal combustion engine is cut off sharply. The greater force also prevents the needle piston from reopening prematurely, so that an unintentional, two-time injection is prevented.
  • the control piston 58 is located in its lowest position, and the needle piston assumes its closed position or is in its closed position. In this position, all fuel fed through the channel 46 from the control pressure source 20 will flow out through the relief opening 54. The latter serves to prevent damage to the control device 32, which could result from the fact that the control piston 58 could impact against the lower end of the second cylinder space.
  • valve piston 58 will not strike the lower end 40, as an increasingly larger area of the drilling opening of the relief opening 54 in the upper end 38 of the cylinder space is released during the downward movement.
  • channel 64 has already been moved out of the area of the location 50 before the upper surface of the control piston 58 has been moved below the drilling opening of the relief opening 54. This ensures that the fuel flow on channel 64 has already been throttled or stopped before pressure can be released via the relief opening.
  • the time delay also ensures that the needle piston 66 remains in its closed position and thus prevents a second unwanted injection process from taking place.
  • the pressure difference between the pressure sources is reduced or built up again to zero, as a result of which the control piston 58 is moved upwards by the force of the spring 74.
  • the spring 74 relaxes over its initial length, as indicated in FIG. 2, and a further cycle can begin.
  • both the time and the amount of fuel to be injected can be determined.
  • the exact time of the fuel injection through the nozzle tip 14 is determined by the opening time at which the needle piston begins to open.
  • the amount of fuel to be injected is determined by the pressure force of the spring and the pressure difference between the pressure sources 20 and 22 and limited by the completion of the fuel connection between the channels 48 and 52. Since the needle piston 66 begins its downward movement in dependence on the downward movement of the control piston after the Spring 74 compressed to a predetermined value and before a pressure drop at interface 70 has been sensed, the fuel to be injected into a combustion chamber can be controlled much more accurately.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel-Injection Apparatus (AREA)
  • Percussion Or Vibration Massage (AREA)
  • Nozzles (AREA)
  • Jet Pumps And Other Pumps (AREA)

Abstract

A control device and method for opening and closing the nozzle of a fuel injector. The control device includes first and second cavities which are formed in the body of the fuel injector, with the second cavity being located close to the nozzle. First and second variable pressure supply chambers are connected to the nozzle and to the two cavities by several fluid passages. A spool valve and a needle valve are positioned in the first and second cavities, respectively, with the spool valve abutting a stem which projects into and terminating in the second cavity. Also situated in the second cavity between the stem and the needle valve is a spring which forms a link therebetween. The spool valve is pressure-actuated by a difference of pressure in the first and second pressure chambers to move between an open and a closed position. In the open position, fluid flow from one of the pressure chambers is permitted through the spool valve and to the second cavity. As the fluid pressure in the second cavity increases to a value greater than the compressive force of the spring, the needle valve will open and allow fluid flow through the nozzle of the fuel injector. As the spool valve moves to its closed position, it compresses the spring further and then urges the needle valve to close. The needle valve closes prior to a drop in fluid pressure in the second cavity.

Description

Die Erfindung bezieht sich auf eine Brennstoffeinspritzdüse mit einem in einem ersten Zylinderraum angeordneten Nadelkolben, der mit einer Ventilnadel zum Öffnen und Schließen einer Einspritz-Öffnung versehen ist und der aus einer Ventilschließstellung durch den Einspritzdruck unter Verspannung einer Feder um einen dem Öffnungsweg entsprechenden Betrag in eine Ventilöffnungsstellung verschiebbar ist, mit einem in einem zweiten Zylinderraum verschiebbar angeordneten Steuerkolben, der sich bei Ventilschließstellung des Nadelkolbens in der vom Nadelkolben fernen Endstellung befindet, der sich gegen die Feder abstützt, der einen zu dem ersten Zylinderraum in den Bereich zwischen Nadelkolben und Ventilöffnung führenden Brennstoffkanal steuert, wobei in der genannten nadelkolbenfernen Endstellung der Brennstoffkanal mit einer Brennstoffdruckquelle verbunden ist,und der bei Ventilöffnungsstellung zur Einleitung der Ventilschließbewegung die Feder bei seiner Verstellbewegung in Richtung zum Nadelkolben um einen weiteren Betrag spannt und dabei den Brennstoffkanal von der Brennstoffdruckquelle trennt.The invention relates to a fuel injector with a needle piston arranged in a first cylinder chamber, which is provided with a valve needle for opening and closing an injection opening and which from a valve closing position by the injection pressure under tension of a spring by an amount corresponding to the opening travel into an Valve opening position is displaceable, with a control piston which is arranged displaceably in a second cylinder chamber and which, when the needle piston is in the valve closed position, is in the end position remote from the needle piston, which is supported against the spring and which leads to a fuel channel leading to the first cylinder chamber in the area between the needle piston and the valve opening controls, with the fuel channel being connected to a fuel pressure source in the end position remote from the needle piston, and which, when the valve is in the open position to initiate the valve closing movement, the spring during its adjustment movement in the direction of the Na delkolben spans by a further amount and thereby separates the fuel channel from the fuel pressure source.

Mit den steigenden Forderungen nach geringerem Benzinverbrauch, geringerer Umweltverschmutzung, etc. werden die Anforderungen an Verbrennungskraftmaschinen und an deren Aggregate immer größer. So haben auch Einspritzdüsen in den zurückliegenden Jahren eine beachtenswerte Fortentwicklung erfahren, und man hat erkannt, daß eine bessere Verbrennung, geringere Rauchentwicklung und geringere Abgase durch ein schnelles Abreißen des Kraftstoffeinspritzvorganges erzielt werden können.With the increasing demands for lower petrol consumption, less pollution, etc., the demands on internal combustion engines and their aggregates are becoming ever greater. Injectors have also undergone remarkable further development in recent years, and it has been recognized that better combustion, less smoke and lower exhaust gases can be achieved by quickly stopping the fuel injection process.

Bei der Düse, von der die Erfindung ausgeht (US-A-2 813 752), öffnet der Nadelkolben pro Arbeitszyklus zweimal, und zwar zunächst für eine Piloteinspritzung und danach für eine Haupteinspritzung.In the nozzle from which the invention is based (US-A-2 813 752), the needle piston opens twice per work cycle, first for a pilot injection and then for a main injection.

Die GB-A-529 141 offenbart ebenfalls eine Einspritzdüse, mit der bei einem Zyklus zwei Einspritzvorgänge erreicht werden. Hierzu sind zwei nebeneinanderliegende Kolben vorgesehen. Ein Kolben wird dabei einenends vom Systemdruck und anderenends durch eine Feder beaufschlagt, wobei der Systemdruck zum Abwärtsbewegen des Kolbens und die Feder zum Aufwärtsbewegen des Kolbens dient. Die Aufwärtsbewegung des Kolbens und damit das Schließen der Ausläße durch den Nadelkolben erfolgt sehr langsam.GB-A-529 141 also discloses an injector with which two injections are achieved in one cycle. For this purpose, two pistons lying next to each other are provided. A piston is acted upon at one end by the system pressure and at the other end by a spring, the system pressure being used to move the piston downwards and the spring to move the piston upwards. The upward movement of the piston and thus the closing of the outlets by the needle piston occurs very slowly.

Die DE-A-2 704 688 zeigt eine Einspritzdüse für schnelle bzw. abrupte Beendigung des Brennstoffeinspritzvorgangs. Im einzelnen ist ein Nadelkolben vorgesehen, der an seinem oberen Ende einen Kolben aufweist, der in einem Druckraum verschiebbar und über eine Feder in Richtung der Schließstellung belastet ist. Der Druckraum ist mit einer Druckspeichereinrichtung verbunden, die zur Wirkung kommt, wenn der Druck in der Zuführleitung abfällt. Dadurch wird der Kolben zusätzlich beaufschlagt, so daß die Rückführung des Nadelkolbens in seine Schließstellung unter der Wirkung der Feder und dem Druck aus der Druckspeichereinrichtung erfolgt.DE-A-2 704 688 shows an injection nozzle for quick or abrupt termination of the fuel injection process. In particular, a needle piston is provided which has at its upper end a piston which is displaceable in a pressure chamber and which is loaded by a spring in the direction of the closed position. The pressure chamber is connected to a pressure storage device, which comes into effect when the pressure in the supply line drops. As a result, the piston is additionally acted upon, so that the needle piston is returned to its closed position under the action of the spring and the pressure from the pressure storage device.

Die FR-A-2 336 563 zeigt zwei Druckquellen und Pumpen.FR-A-2 336 563 shows two pressure sources and pumps.

Demgegenüber wird die mit der Erfindung zu lösende Aufgabe darin gesehen, die Brennstoffeinspritzdüse derart auszubilden, daß bei Beibehaltung eines schnellen Abreißens des Einspritzvorganges der Schließdruck größer ist als der Öffnungsdruck.In contrast, the object to be achieved with the invention is seen in designing the fuel injector in such a way that the closing pressure is greater than the opening pressure while maintaining a rapid tearing off of the injection process.

Diese Aufgabe ist gemäß der Erfindung dadurch gelöst worden, daß der Steuerkolben auf der nadelkolbenfernen Seite von einer zweiten Druckquelle, einer Steuerdruckquelle und auf der nadelkolbennahen Seite von der ersten, der Brennstoffdruckquelle beaufschlagt ist und daß der Druck der Brennstoffdruckquelle und der Druck der Steuerdruckquelle zur Einleitung und Durchführung der Ventilöffnungs- und Schließbewegung steuerbar sind, wobei der zweite Zylinderraum in seinem vom Steuerdruck beaufschlagbaren Abschnitt zur Druckentlastung mit einem Sammelbehälter verbindbar ist.This object has been achieved according to the invention in that the control piston is acted upon on the side remote from the needle piston by a second pressure source, a control pressure source and on the side near the needle piston by the first, the fuel pressure source, and in that the pressure of the fuel pressure source and the pressure of the control pressure source for introduction and implementation of the valve opening and closing movement are controllable, the second cylinder space being connectable to a collecting container in its section which can be acted upon by the control pressure for pressure relief.

Auf diese Weise werden der Nadelkolben und der Steuerkolben in einem unbeaufschlagten Zustand, d.h., wenn der Motor noch nicht angelassen wurde, in ihren Ausgangsstellungen sich befinden, in denen der Nadelkolben sich in seiner Ventilschließstellung und der Steuerkolben in seiner entgegengesetzten oder vom Nadelkolben fernen Endstellung anliegt. Bei Beaufschlagung der Düse und damit des Nadelkolbens baut sich in der Düse ein Druck auf, der schließlich den Nadelkolben von seinem Sitz abhebt und ihn gegen die Wirkung der Feder, verschiebt, die dadurch zusammengedrückt wird. Die Verschiebung durch den Einspritzdruck dauert so lange, bis der maximale Einspritzdruck erreicht ist - in diesem Zustand wird der Nadelkolben eine Art Schwimmstellung einnehmen - oder bis der Nadelkolben gegen einen Anschlag führt. Zum Schließen des Nadelkolbens muß nun der Steuerkolben betätigt werden. Der Zeitpunkt der Verschiebung wird von verschiedenen Parametern der Verbrennungskraftmaschine abhängig gemacht, und je nach Wahl des Schließzeitpunktes läßt sich die einzuspritzende Kraftstoffmenge genau festlegen. Bei der Verschiebung des Steuerkolbens aus seiner Endstellung heraus wird aber die Feder - diesmal von der entgegengesetzten Seite - um ein weiteres Maß zusammengedrückt. Hierbei muß der Öffnungsdruck nicht sofort erreicht werden, sondern eventuell mit einer Zeitverzögerung. Wird aber die resultierende Kraft aus Druckkraft und Federkraft den Öffnungsdruck überwinden oder der Öffnungsdruck plötzlich abgebaut, so wird die Feder den Nadelkolben wieder in seine Ventilschließstellung verschieben. Danach kann der Steuerkolben entlastet werden und die Feder schiebt ihn in seine Ausgangsstellung zurück. Im ganzen gesehen wird die Feder zum Schließen des Nadelkolbens noch einmal zusätzlich gespannt, so daß sich letztlich ein Schließdruck ergibt, der über dem Öffnungsdruck liegt.In this way, the needle piston and the control piston will be in an unloaded state, ie if the engine has not yet been started, in their starting positions, in which the needle piston is in its valve-closed position and the control piston is in its opposite or distant end position from the needle piston . When the nozzle and thus the needle piston are acted upon, pressure builds up in the nozzle, which finally lifts the needle piston from its seat and displaces it against the action of the spring, which is thereby compressed. The displacement by the injection pressure lasts until the maximum injection pressure is reached - in this state, the needle piston will assume a kind of floating position - or until the needle piston leads against a stop. The control piston must now be actuated to close the needle piston. The time of the shift is made dependent on various parameters of the internal combustion engine, and the amount of fuel to be injected can be precisely determined depending on the selection of the closing time. When the control piston is moved out of its end position, however, the spring - this time from the opposite side - is compressed by a further amount. The opening pressure does not have to be reached immediately, but possibly with a time delay. However, if the resulting force from the pressure force and spring force overcomes the opening pressure or the opening pressure is suddenly reduced, the spring will move the needle piston back into its valve closing position. Then the control piston can be relieved and the spring pushes it back into its starting position. in the seen as a whole, the spring for closing the needle piston is additionally tensioned, so that ultimately there is a closing pressure which is above the opening pressure.

Zum leichten Verschließen des den Kraftstoff zum Nadelkolben leitenden Brennstoffkanals ist nach der Erfindung vorgesehen, daß in dem Steuerkolben ein Kanal vorgesehen ist, der den Brennstoffkanal mit einem weiteren zur Brennstoffdruckquelle führenden Kanal in seiner vom Nadelkolben fernen Endstellung verbindet. Durch diese Maßnahme wird der erfindungsgemäß als Ringkanal ausgebildete Kanal im Steuerkolben bei dessen Beaufschlagung nach und nach die Verbindung mit dem den Kraftstoff zum Nadelkolben leitenden Brennstoffkanal unterbrechen, so daß der Kraftstofffluß zunächst gedrosselt und dann ganz unterbunden wird. Während der Drosselung bleibt der Einspritzdruck noch so groß, daß der Nadelkolben in seiner geöffneten Position verbleibt.For easy closing of the fuel channel guiding the fuel to the needle piston, it is provided according to the invention that a channel is provided in the control piston, which connects the fuel channel with another channel leading to the fuel pressure source in its end position remote from the needle piston. By this measure, the channel designed according to the invention as an annular channel in the control piston is gradually interrupted when it is acted upon, so that the connection to the fuel channel guiding the fuel to the needle piston, so that the fuel flow is initially throttled and then completely prevented. During throttling, the injection pressure remains so high that the needle piston remains in its open position.

Dadurch, daß die Ventilöffnungsstellung des Nadelkolbens durch einen Haltering begrenzt ist, wird erreicht, daß der Einspritzdruck relativ groß sein kann und der Nadelkolben bei beaufschlagtem Steuerkolben mit einer Zeitverzögerung schließt.The fact that the valve opening position of the needle piston is limited by a retaining ring means that the injection pressure can be relatively high and the needle piston closes with a time delay when the control piston is acted on.

Zur möglichen Verbindung des zweiten Zylinderraums mit dem Sammelbehälter wird nach der Erfindung vorgeschlagen, daß der zweite Zylinderraum mit einer Entlastungsöffnung versehen ist, die von der nadelkolbenfernen Seite der Steuerkolbens beim oder nach dem Unterbrechen der Verbindung des Brennstoffkanals mit der Brennstoffdruckquelle geöffnet wird.For the possible connection of the second cylinder chamber to the collecting container, it is proposed according to the invention that the second cylinder chamber is provided with a relief opening which is opened from the side of the control piston remote from the needle piston when or after the connection of the fuel channel to the fuel pressure source is interrupted.

In der Zeichnung ist ein nachfolgend näher erläutertes Ausführungsbeispiel der Erfindung dargestellt. Es zeigt:

  • Fig. 1 eine Brennstoffeinspritzdüse, teilweise im Schnitt;
  • Fig. 2 die Brennstoffeinspritzdüse nach Fig. 1, jedoch in einem größeren Maßstab, wobei der Steuerkolben sich in seiner obersten Stellung und der Nadelkolben in seiner geschlossenen Stellung befindet;
  • Fig. 3 eine ähnliche Darstellung wie Fig. 2, jedoch den Steuerkolben in einer Zwischenstellung und den Nadelkolben in seiner teilweise geöffneten Stellung zeigend, und
  • Fig. 4 die Brennstoffeinspritzdüse nach Fig. 1 mit einem sich in seiner untersten Stellung befindlichen Steuerkolben und einem sich in seiner geschlossenen Position befindlichen Nadelkolben.
In the drawing, an embodiment of the invention explained in more detail below is shown. It shows:
  • Figure 1 is a fuel injector, partially in section.
  • Figure 2 shows the fuel injector of Figure 1, but on a larger scale, with the control piston in its uppermost position and the needle piston in its closed position;
  • Fig. 3 is a view similar to Fig. 2, but showing the control piston in an intermediate position and the needle piston in its partially open position, and
  • Fig. 4 shows the fuel injector of Fig. 1 with a control piston in its lowermost position and a needle piston in its closed position.

In Figur 1 der Zeichnung ist eine Brennstoffeinspritzdüse mit 10, ihr Düsenkörper mit 12 und eine an einem Ende des Düsenkörpers vorgesehene Düsenspitze mit 14 bezeichnet. Über ein Gewinde 16 kann der Düsenkörper 12 in einen der Einfachheit halber nicht dargestellten Zylinderkopf einer Verbrennungskraftmaschine derart eingeschraubt werden, daß ihre Düsenspitze 14 mit einem Brennraum in Verbindung steht. In diesen Brennraum wird Kraftstoff in einem feinen Schleier eingespritzt, wozu in der Düsenspritze 14 einige Einspritzöffnungen 18 vorgesehen sind. Um aber den Einspritzvorgang genau steuern zu können, sind zunächst in dem Düsenkörper 12 der Brennstoffeinspritzdüse 10 eine Steuerdruckquelle 20 und eine Brennstoffdruckquelle 22 vorgesehen, von denen jede mit einem Sammelbehälter 24 und 28 und einer gesonderten Pumpe 26 und 30 verbunden ist. Hierbei können die Steuer- und Brennstoffdruckquelle 20, 22 als Flüssigkeitszuführraum mit veränderbarem Druck ausgebildet sein und dem Steuerungs- und Zumeßraum entsprechen, wie sie bei einigen Einspritzdüsen bereits vorkommen. Bei diesen Einspritzdüsen dient der Steuerungsraum zur Steuerung des Einspritzzeitpunktes und der Zumeßraum zur Bestimmung der Einspritzmenge. In dem Düsenkörper 12 ist noch eine Steuereinrichtung 32 eingesetzt, die den Kraftstoffdurchfluß durch die Brennstoffeinspritzdüse 10 reguliert. Sie weist im einzelnen einen ersten und einen zweiten Zylinderraum 36 und 34 auf, die zueinander im Düsenkörper axial derart ausgerichtet sind, daß der erste Zylinderraum 36 in unmittelbarer Nähe der Düsenspitze 14 zu liegen kommt. Damit liegen die Zylinderräume zwischen den Druckquellen, mit denen sie ebenso wie untereinander verbunden sind, und der Düsenspitze, wobei ihre oberen und unteren Enden mit 38, 40 und 42, 44 bezeichnet sind. Was aber ihre Verbindung mit den Druckquellen anbelangt, so ist das obere Ende 38 des Zylinderraumes 34 über einen ersten Kanal 46 mit der Steuerdruckquelle 20 und sein unteres Ende 40 als auch eine Stelle 50, die etwa mittig zwischen dem oberen und unteren Ende 38 und 40 liegt, mit der Brennstoffdruckquelle 22 über eine zweite Leitung 48 verbunden. Ein Brennstoffkanal 52 verbindet den zweiten Zylinderraum 34 in etwa im Bereich der Stelle 50 mit dem unteren Ende 44 oder Endbereich des ersten Zylinderraums 36. Ein Entlastungskanal oder eine Entlastungsöffnung 54 wiederum schließt den zweiten Zylinderraum 34 im Bereich seines oberen Endes 38 an einen Sammelbehälter 56 an, der mit dem Sammelbehälter 24 und/oder 28 verbunden sein kann. Anstelle der Entlastungsbohrung 54 kann aber auch ein Entlastungsventil in dem ersten Kanal 46 vorgesehen werden und die Sammelbehälter könnten auch in der Einspritzdüse integriert sein.In FIG. 1 of the drawing, a fuel injection nozzle is designated by 10, its nozzle body by 12, and a nozzle tip provided at one end of the nozzle body by 14. Via a thread 16, the nozzle body 12 can be screwed into a cylinder head of an internal combustion engine, which is not shown for the sake of simplicity, in such a way that its nozzle tip 14 is connected to a combustion chamber. Fuel is injected into this combustion chamber in a fine veil, for which purpose a few injection openings 18 are provided in the nozzle syringe 14. However, in order to be able to control the injection process precisely, a control pressure source 20 and a fuel pressure source 22 are first provided in the nozzle body 12 of the fuel injection nozzle 10, each of which is connected to a collecting container 24 and 28 and a separate pump 26 and 30. In this case, the control and fuel pressure sources 20, 22 can be designed as a liquid supply chamber with variable pressure and correspond to the control and metering chamber, as is already the case with some injection nozzles. With these injection nozzles, the control space serves to control the injection timing and the metering space to determine the injection quantity. A control device 32 is also inserted in the nozzle body 12, which regulates the fuel flow through the fuel injection nozzle 10. In detail, it has a first and a second cylinder space 36 and 34, which are axially aligned with one another in the nozzle body such that the first cylinder space 36 comes to lie in the immediate vicinity of the nozzle tip 14. The cylinder spaces thus lie between the pressure sources to which they are connected, as well as to one another, and the nozzle tip, their upper and lower ends being denoted by 38, 40 and 42, 44. However, as far as their connection to the pressure sources is concerned, the upper end 38 of the cylinder space 34 is connected to the control pressure source 20 via a first channel 46 and its lower end 40 as well as a point 50 which is approximately midway between the upper and lower ends 38 and 40 is connected to the fuel pressure source 22 via a second line 48. A fuel channel 52 connects the second cylinder space 34 approximately in the area of the point 50 to the lower end 44 or end area of the first cylinder space 36. A relief channel or a relief opening 54 in turn connects the second cylinder space 34 to a collecting container 56 in the area of its upper end 38 , which can be connected to the collecting container 24 and / or 28. Instead of the relief bore 54, a relief valve can also be provided in the first channel 46 and the collection containers could also be integrated in the injection nozzle.

Die Steuereinrichtung ist ferner mit einem ersten Ventil, einem Steuerkolben 58 ausgestattet, der in dem Zylinderraum 34 verschiebbar ist und gegen eine Stange 60 anliegt. Letztere erstreckt sich bis in den ersten Zylinderraum 36 und ist dort mit einem Querteil 62, wie einem Stift, verbunden. Des weiteren ist in den Steuerkolben ein Kanal 64 oder eine Ringnut eingearbeitet, so daß zwei Kolbenstücke entstehen, zwischen denen eine Verbindung des Kanals 48 mit dem Brennstoffkanal 52 entsteht, sofern sich der Steuerkolben 58 in seiner in Figur 1 oder 2 gezeigten obersten Stellung befindet. Der Steuerkolben 58 ist zwischen seinen Endstellungen, d.h. zwischen seiner obersten in Figur 1 und 2 wiedergegebenen Stellung und seiner untersten, in Figur 4 gezeigten Position durch Druckunterschiede, die in den Druckquellen 20 und 22 geschaffen werden, verschiebbar. Diese Druckunterschiede wirken auf das obere und untere Ende 38 und 40 des zweiten Zylinderraums 34 und damit auch auf den Steuerkolben 58. Wird der Steuerkolben 58 aber aus seiner in Figur 1 oder 2 wiedergegebenen Position nach unten verstellt, und zwar in Richtung auf seine unterste Stellung, dann wird der Kanal 64 nicht mehr zu der Stelle 50 ausgerichtet sein, so daß der Kraftstoff auch nicht mehr vom Kanal 48 zum Brennstoffkanal 52 oder umgekehrt gelangen kann. Andererseits wird der Steuerkolben 58 in dieser Stellung verhindern, daß Abgase aus dem Brennraum durch die Kanäle 52 und 48 in die Brennstoffdruckquelle gelangen.The control device is also equipped with a first valve, a control piston 58, which is displaceable in the cylinder space 34 and bears against a rod 60. The latter extends into the first cylinder space 36 and is connected there to a transverse part 62, such as a pin. Furthermore, a channel 64 or an annular groove is machined into the control piston, so that two piston pieces are formed, between which a connection of the channel 48 to the fuel channel 52 is created, provided the control piston 58 is in its position in FIG. 1 or 2 shown top position. The control piston 58 is displaceable between its end positions, that is to say between its uppermost position shown in FIGS. 1 and 2 and its lowest position shown in FIG. 4 by pressure differences which are created in the pressure sources 20 and 22. These pressure differences act on the upper and lower ends 38 and 40 of the second cylinder chamber 34 and thus also on the control piston 58. However, the control piston 58 is adjusted downward from its position shown in FIG. 1 or 2, in the direction of its lowest position , then the channel 64 will no longer be aligned with the point 50, so that the fuel can no longer get from the channel 48 to the fuel channel 52 or vice versa. On the other hand, the control piston 58 in this position will prevent exhaust gases from the combustion chamber from entering the fuel pressure source through the channels 52 and 48.

Ein zweites Ventil, ein Nadelkolben 66 mit Stufendruckflächen, ist in dem ersten Zylinderraum 36 vorgesehen und zwischen einer offenen und geschlossenen Stellung verschiebbar. In diesem kann einmal Kraftstoff durch die Düsenspitze 14 austreten, oder der Austritt von Kraftstoff wird unterbunden. Die obere Oberfläche des Nadelkolbens 66 ist mit 68, eine Zwischenfläche mit 70 und eine konische Grundfläche mit 72 bezeichnet. Letztere sitzt auf einem Stiz 73 auf, wenn sich der Nadelkolben 66 in seiner geschlossenen Stellung befindet. In dieser Stellung ist die vom Kraftstoff beaufschlagte Fläche kleiner als die obere Oberfläche 68, weil der Kraftstoff nur die Zwischenfläche 70 beaufschlagen kann. Befindet sich aber der Nadelkolben 66 in seiner offenen oder oberen Stellung, dann kann der Kraftstoff zusätzlich zur Zwischenfläche 70 noch die Grundfläche 72 beaufschlagen. Der Nadelkolben 66 wird zwischen seiner offenen und geschlossenen Stellung durch die Bewegung des Steuerkolbens 58 und den Kraftstoffdruck verschoben, der, wie ausgeführt, auf die Zwischenfläche und zusätzlich auf die Grundfläche einwirken kann. Diese Doppelbetätigung macht es der Steuereinrichtung 32 möglich, auf einen Druckabfall am Kanal 64 bereits zu einem Zeitpunkt zu reagieren, in dem in dem ersten Zylinderraum 36 ein Druckabfall noch nicht ermittelt wurde. Dies wirkt sich darin aus, daß der Nadelkolben 66 bereits in seine geschlossene Stellung gedrückt wird, bevor er einen Druckabfall in dem ersten Zylinderraum 36 ermitteln konnte.A second valve, a needle piston 66 with step pressure surfaces, is provided in the first cylinder space 36 and can be moved between an open and a closed position. In this, fuel can escape through the nozzle tip 14 once or the leakage of fuel is prevented. The upper surface of the needle piston 66 is designated 68, an interface 70 and a conical base 72. The latter sits on a stiz 73 when the needle piston 66 is in its closed position. In this position, the area exposed to the fuel is smaller than the upper surface 68 because the fuel can only affect the intermediate surface 70. However, if the needle piston 66 is in its open or upper position, the fuel can act on the base surface 72 in addition to the intermediate surface 70. The needle piston 66 is displaced between its open and closed positions by the movement of the control piston 58 and the fuel pressure which, as stated, can act on the intermediate surface and additionally on the base surface. This double actuation enables the control device 32 to react to a drop in pressure on the channel 64 at a point in time at which a drop in pressure has not yet been determined in the first cylinder space 36. This has the effect that the needle piston 66 is already pressed into its closed position before it was able to determine a pressure drop in the first cylinder space 36.

In dem ersten Zylinderraum 36 befindet sich außerdem zwischen der oberen Oberfläche 68 des Nadelkolbens 66 und dem Querteil 62 eine Feder 74, die dazu dient, Steuerkolben 58 und Nadelkolben 66 voneinander fort zu drücken. Die Aufwärtsbewegung des Nadelkolbens wird durch einen Haltering 76 begrenzt, der ebenfalls in dem ersten Zylinderraum angeordnet ist.In the first cylinder space 36 there is also a spring 74 between the upper surface 68 of the needle piston 66 and the transverse part 62, which serves to push the control piston 58 and the needle piston 66 away from one another. The upward movement of the needle piston is limited by a retaining ring 76, which is also arranged in the first cylinder space.

Unter Bezugnahme auf die Figuren 2 bis 4 wird nachfolgend die Arbeitsweise der Brennstoffeinspritzdüse 10 erläutert. In Figur 2 ist die Ausgangsposition dargestellt, in der in den Druckquellen 20 und 22 keine Druckdifferenz herrscht und der Druck die Bewegung der Steuereinrichtung 32 beeinflußt. In dieser Stellung befindet sich der Steuerkolben 58 in seiner obersten Stellung und Kraftstoff kann über den Kanal 64 aus dem Kanal 48 in den Brennstoffkanal 52 bis in den Nadelkolben 66 gelangen, der sich dann noch in seiner geschlossenen Stellung befindet, in der die Grundfläche 72 den Sitz 73 verschließt. In dieser Stellung ist die Feder 74 leicht zusammengepreßt, wodurch der Steuerkolben 58 und der Nadelkolben 66 voneinander fort gedrückt werden. Danach wird der Kraftstoffdruck in den beiden Druckquellen 20 und 22 über die Pumpen 26 und 30 bis auf einen vorherbestimmten Wert erhöht, der dann auf die Zwischenfläche 70 wirkt und die Kraft der Feder ausbalanciert. Diese Druckgleichheit läßt den Nadelkolben 66 weiter auf seinem Sitz verbleiben, ist aber derart, daß der Nadelkolben bei einem zusätzlichen Druckanstieg sofort öffnet. Wird der Druck in den beiden Druckquellen 20 und 22 gleichzeitig erhöht, so wird er sich bis zur Zwischenfläche 70 des Nadelkolbens 66 fortpflanzen und ihn entgegen der Kraft der Feder 74 nach oben verschieben. Der Nadelkolben 66 wird dabei geöffnet und Kraftstoff kann durch die Einspritzöffnungen 18 in der Düsenspitze 14 in den Brennraum des Verbrennungsmotors gelangen. Bei der Aufwärtsbewegung wird auch die Fläche des Nadelkolbens 66, die dem Kraftstoffdruck ausgesetzt ist, vergrößert, da dann der Kraftstoffdruck nicht nur die Zwischenfläche 70, sondern auch die Grundfläche 72 beaufschlagt. Hierdurch wird der Druckanstieg so groß, daß die Feder 74 nicht mehr in der Lage ist, den Nadelkolben 66 zu schließen. Er bleibt deshalb in seiner offenen Position.The mode of operation of the fuel injector 10 is explained below with reference to FIGS. 2 to 4. FIG. 2 shows the starting position in which there is no pressure difference in the pressure sources 20 and 22 and the pressure influences the movement of the control device 32. In this position, the control piston 58 is in its uppermost position and fuel can pass through the channel 64 from the channel 48 into the fuel channel 52 into the needle piston 66, which is then still in its closed position, in which the base surface 72 Seat 73 closes. In this position, the spring 74 is slightly compressed, whereby the control piston 58 and the needle piston 66 are pressed away from each other. The fuel pressure in the two pressure sources 20 and 22 is then increased via the pumps 26 and 30 to a predetermined value, which then acts on the intermediate surface 70 and balances the force of the spring. This equality of pressure allows the needle piston 66 to remain in its seat, but is such that the needle piston opens immediately with an additional pressure increase. If the pressure in the two pressure sources 20 and 22 is increased at the same time, it will propagate to the intermediate surface 70 of the needle piston 66 and move it upward against the force of the spring 74. The needle piston 66 is opened and fuel can enter the combustion chamber of the internal combustion engine through the injection openings 18 in the nozzle tip 14. During the upward movement, the area of the needle piston 66 that is exposed to the fuel pressure is also increased, since the fuel pressure then acts not only on the intermediate surface 70 but also on the base area 72. As a result, the pressure increase becomes so great that the spring 74 is no longer able to close the needle piston 66. He therefore remains in his open position.

Zu einem vorbestimmten Zeitpunkt wird dann in den Druckquellen 20 und 22 eine Druckdifferenz erzeugt, wobei der Druck in der Brennstoffdruckquelle 22 kleiner ist, so daß sich der Steuerkolben 58 nach unten in Richtung auf seine zweite Stellung bewegt. Dies ist in Figur 3 veranschaulicht, aus der zu ersehen ist, daß der Kanal 64 nicht mehr zu den Kanälen 48 und 52 bzw. zu der Stelle 50 ausgerichtet ist. Dadurch wird der Kraftstofffluß zwischen den Kanälen 48 und 52 zunächst gedrosselt und später ganz unterbunden. Gleichzeitig wird bei dieser nach unten gerichteten Bewegung die Feder 74 weiter zusammengedrückt, da dann auf die Feder der Querteil 62 infolge der gegen den Steuerkolben anliegenden Stange 60 wirkt. Die Feder 74 wird so lange zusammengedrückt, bis ihre Federkraft der Differenz der Drücke entspricht, die auf die Oberseite des Steuerkolbens 58 und auf die Zwischenfläche 70 und Grundfläche 72 des Nadelkolbens 66 wirken. Zu etwa einem solchen Zeitpunkt, insbesondere bei weiterem Druckanstieg, wirkt die Feder 74 als eine mechanische Stange und bewirkt eine Abwärtsbewegung des Nadelkolbens 66, die unmittelbar von der Abwärtsbewegung des Steuerkolbens abhängig ist. Unmittelbar bevor die Kraftstoffverbindung über den Kanal 64 ganz unterbrochen wird infolge der Abwärtsbewegung des Steuerkolbens 58, wird die Kraft der Feder der Druckdifferenz entsprechen, die zwischen den Druckquellen 20 und 22 herrscht. Der Nadelkolben 66 wird dann bereits wieder mit seiner Abwärtsbewegung beginnen. Dies kann deshalb erfolgen, weil, nachdem der Kanal 64 aus dem Bereich der Stelle 50 geschoben wurde und damit über den Kanal 64 kein Kraftstoff mehr fließen kann, der Druck an der Zwischenfläche 70 und der Grundfläche 72 sich abzubauen beginnt. Der Druckabfall basiert auf zwei Faktoren, und zwar wird ein Teil des Kraftstoffes durch die Düsenspitze austreten und zum anderen ist der Kraftstofffluß aus der Brennstoffdruckquelle 22 gedrosselt oder ganz unterbunden. Der Druck in der Brennstoffquelle wird so lange abfallen, bis sich der Nadelkolben 66 wieder in seiner geschlossenen Stellung befindet, in der durch die Düsenspitze kein Kraftstoff mehr austreten kann. Da bei diesem Vorgang die Druckkraft der Feder 74 höher als bei der Aufwärtsbewegung des Nadelkolbens 66 ist und der Druck unterhalb des Nadelkolbens 66 ständig abnimmt, wird der Nadelkolben 66 sehr schnell schließen. Hieraus geht hervor, daß die Kraft, die zum Schließen des Nadelkolbens 66 erforderlich ist, größer ist als die Kraft, die zum Öffnen des Nadelkolbens benötigt wird. Durch dieses Merkmal wird ein scharfes Abreißen des Kraftstoffflusses durch die Düsenspitze im Brennraum des Verbrennungsmotors erreicht. Die größere Kraft verhindert auch ein frühzeitiges Wiederöffnen des Nadelkolbens, so daß ein ungewolltes, zweimaliges Einspritzen verhindert wird. In Figur 4 ist der Steuerkolben 58 sich in seiner untersten Stellung befindlich eingezeichnet, und der Nadelkolben nimmt seine Schließstellung ein oder befindet sich in seiner geschlossenen Stellung. In dieser Stellung wird aller durch den Kanal 46 aus der Steuerdruckquelle 20 eingespeister Kraftstoff durch die Entlastungsöffnung 54 abströmen. Letztere dient dazu, Beschädigungen an der Steuereinrichtung 32 zu verhindern, die dadurch entstehen könnten, daß der Steuerkolben 58 gegen das untere Ende des zweiten Zylinderraumes prallen könnte. Obwohl die Druckdifferenz zwischen den Druckquellen groß ist, wird der Ventilkolben 58 nicht auf das untere Ende 40 aufprallen, da bei der Abwärtsbewegung ein immer größer werdender Bereich der Bohröffnung der Entlastungsöffnung 54 im oberen Ende 38 des Zylinderraums freigegeben wird. Hierbei ist auch festzuhalten, daß der Kanal 64 bereits aus dem Bereich der Stelle 50 hinaus verschoben wurde, bevor die obere Oberfläche des Steuerkolbens 58 unter die Bohröffnung der Entlastungsöffnung 54 verschoben worden ist. Dies gewährleistet, daß der Kraftstofffluß am Kanal 64 bereits gedrosselt oder unterbunden wurde, bevor ein Druckabbau über die Entlastungsöffnung erfolgen konnte. Die Zeitverzögerung stellt außerdem sicher, daß der Nadelkolben 66 in seiner Schließstellung verbleibt und somit verhindert, daß ein zweiter ungewollter Einspritzvorgang stattfindet.At a predetermined point in time, a pressure difference is then generated in the pressure sources 20 and 22, the pressure in the fuel pressure source 22 being lower, so that the control piston 58 moves downward in the direction of its second position. This is illustrated in FIG. 3, from which it can be seen that the channel 64 is no longer aligned with the channels 48 and 52 or with the location 50. As a result, the fuel flow between the channels 48 and 52 is initially throttled and later completely prevented. At the same time, the spring 74 is further compressed during this downward movement, since the transverse part 62 then acts on the spring as a result of the rod 60 resting against the control piston. The spring 74 is compressed until its spring force corresponds to the difference in the pressures which act on the upper side of the control piston 58 and on the intermediate surface 70 and base surface 72 of the needle piston 66. At about such a time, particularly when the pressure continues to rise, the spring 74 acts as a mechanical rod and causes the needle piston 66 to move downward is directly dependent on the downward movement of the control piston. Immediately before the fuel connection via the channel 64 is completely interrupted due to the downward movement of the control piston 58, the force of the spring will correspond to the pressure difference that prevails between the pressure sources 20 and 22. The needle piston 66 will then begin its downward movement again. This can take place because after the channel 64 has been pushed out of the area of the location 50 and therefore no more fuel can flow through the channel 64, the pressure at the intermediate surface 70 and the base surface 72 begins to decrease. The pressure drop is based on two factors, namely that a part of the fuel will emerge through the nozzle tip and on the other hand the fuel flow from the fuel pressure source 22 is throttled or completely prevented. The pressure in the fuel source will drop until the needle piston 66 is again in its closed position, in which no more fuel can escape through the nozzle tip. Since in this process the pressure force of the spring 74 is higher than during the upward movement of the needle piston 66 and the pressure below the needle piston 66 constantly decreases, the needle piston 66 will close very quickly. It can be seen from this that the force required to close the needle piston 66 is greater than the force required to open the needle piston. This feature ensures that the fuel flow through the nozzle tip in the combustion chamber of the internal combustion engine is cut off sharply. The greater force also prevents the needle piston from reopening prematurely, so that an unintentional, two-time injection is prevented. In Figure 4, the control piston 58 is located in its lowest position, and the needle piston assumes its closed position or is in its closed position. In this position, all fuel fed through the channel 46 from the control pressure source 20 will flow out through the relief opening 54. The latter serves to prevent damage to the control device 32, which could result from the fact that the control piston 58 could impact against the lower end of the second cylinder space. Although the pressure difference between the pressure sources is large, the valve piston 58 will not strike the lower end 40, as an increasingly larger area of the drilling opening of the relief opening 54 in the upper end 38 of the cylinder space is released during the downward movement. It should also be noted here that the channel 64 has already been moved out of the area of the location 50 before the upper surface of the control piston 58 has been moved below the drilling opening of the relief opening 54. This ensures that the fuel flow on channel 64 has already been throttled or stopped before pressure can be released via the relief opening. The time delay also ensures that the needle piston 66 remains in its closed position and thus prevents a second unwanted injection process from taking place.

Zu einem weiteren vorherbestimmten Zeitpunkt wird die Druckdifferenz zwischen den Druckquellen wieder auf Null ab- bzw. aufgebaut, wodurch der Steuerkolben 58 durch die Kraft der Feder 74 aufwärts bewegt wird. Dabei entspannt sich die Feder 74 auf ihrer Anfangslänge, wie sie in Figur 2 angedeutet ist, und ein weiterer Zyklus kann beginnen.At a further predetermined point in time, the pressure difference between the pressure sources is reduced or built up again to zero, as a result of which the control piston 58 is moved upwards by the force of the spring 74. The spring 74 relaxes over its initial length, as indicated in FIG. 2, and a further cycle can begin.

Durch Veränderung der Druckdifferenz zwischen den Druckquellen 20 und 22 kann sowohl der Zeitpunkt als auch die Menge des einzuspritzenden Kraftstoffes bestimmt werden. Der genaue Zeitpunkt der Kraftstoffeinspritzung durch die Düsenspitze 14 wird durch den Öffnungszeitpunkt, zu dem der Nadelkolben zu öffnen beginnt, bestimmt. Die einzuspritzende Kraftstoffmenge wird durch die Druckkraft der Feder und die Druckdifferenz zwischen den Druckquellen 20 und 22 bestimmt und begrenzt durch das Abschließen der Kraftstoffverbindung zwischen den Kanälen 48 und 52. Da der Nadelkolben 66 seine Abwärtsbewegung in Ahängigkeit von der Abwärtsbewegung des Steuerkolbens beginnt, nachdem die Feder 74 auf einen vorherbestimmten Wert zusammengedrückt und bevor ein Druckabfall an der Zwischenfläche 70 wahrgenommen wurde, kann der in eine Brennkammer einzuspritzende Kraftstoff wesentlich genauer gesteuert werden.By changing the pressure difference between the pressure sources 20 and 22, both the time and the amount of fuel to be injected can be determined. The exact time of the fuel injection through the nozzle tip 14 is determined by the opening time at which the needle piston begins to open. The amount of fuel to be injected is determined by the pressure force of the spring and the pressure difference between the pressure sources 20 and 22 and limited by the completion of the fuel connection between the channels 48 and 52. Since the needle piston 66 begins its downward movement in dependence on the downward movement of the control piston after the Spring 74 compressed to a predetermined value and before a pressure drop at interface 70 has been sensed, the fuel to be injected into a combustion chamber can be controlled much more accurately.

Claims (5)

1. Fuel injection nozzle having a needle piston (66) arranged in a first cylinder chamber (36), the needle piston being provided with a valve needle for opening and closing an injection port and being movable from a valve closing position by the injection pressure, with accompanying tensioning of a spring (74), by an amount corresponding to the opening travel into a valve opening position, and having a control piston (58) which is slidably arranged in a second cylinder chamber (34), is in the end position remote from the needle piston (66) when the needle piston (66) is in the valve closing position, is supported against the spring (74), and controls a fuel duct (52) leading to the first cylinder chamber (36) into the zone between the needle piston (66) and the valve port, the fuel duct (52) being connected to a fuel pressure source (22) in the said end position remote from the needle piston, and, in the valve opening position, in order to initiate the valve closing movement, tensions the spring (74) by a further amount on its adjusting movement towards the needle piston (66) and in so doing isolates the fuel duct (52) from the fuel pressure source, characterised in that pressure is applied to the control piston (58) on the side remote from the needle piston from a second pressure source, a control pressure source (20), and from the first, fuel pressure source on the side close to the needle piston, and the pressure of the fuel pressure source and the pressure of the control pressure source are controllable for initiating and carrying out the valve opening and closing movements, the second cylinder chamber (34) being connectable for pressure relief to a reservoir (24) in that section of the chamber to which the control pressure can be admitted.
2. Fuel injection nozzle according to claim 1, characterised in that a duct (64) is provided in the control piston (58) which connects the fuel duct (52) to another duct (48) leading to the fuel pressure source (22) in the end position of the control piston remote from the needle piston (66).
3. Fuel injection nozzle according to claim 2, characterised in that the duct (64) in the control piston (58) is in the form of an annular duct.
4. Fuel injection nozzle according to one or more of the preceding claims, characterised in that the valve opening position of the needle piston (66) is defined by a retaining ring (76).
5. Fuel injection nozzle according to one or more of the preceding claims, characterised in that the second cylinder chamber (34) is provided with a relief port (54) which is opened from that side of the control piston (58) which is remote from the needle piston on or after the interruption of the connection of the fuel duct (52) with the fuel pressure source (22).
EP83102731A 1982-03-29 1983-03-19 Needle-valve injection nozzle Expired EP0090296B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT83102731T ATE21437T1 (en) 1982-03-29 1983-03-19 INJECTOR WITH A NEEDLE PISTON.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US362815 1982-03-29
US06/362,815 US4465231A (en) 1982-03-29 1982-03-29 Control device and method for activating a fuel injector nozzle

Publications (2)

Publication Number Publication Date
EP0090296A1 EP0090296A1 (en) 1983-10-05
EP0090296B1 true EP0090296B1 (en) 1986-08-13

Family

ID=23427647

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83102731A Expired EP0090296B1 (en) 1982-03-29 1983-03-19 Needle-valve injection nozzle

Country Status (10)

Country Link
US (1) US4465231A (en)
EP (1) EP0090296B1 (en)
JP (1) JPS58185971A (en)
AT (1) ATE21437T1 (en)
AU (1) AU551978B2 (en)
BR (1) BR8301565A (en)
CA (1) CA1198022A (en)
DE (1) DE3365234D1 (en)
ES (1) ES521040A0 (en)
ZA (1) ZA832191B (en)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61187567A (en) * 1985-02-15 1986-08-21 Kawasaki Heavy Ind Ltd Gas injection valve
US5029759A (en) * 1989-11-17 1991-07-09 Cummins Engine Company, Inc. Curved hole machining method and fuel injector formed thereby
DE4408245A1 (en) * 1994-03-11 1995-09-14 Bosch Gmbh Robert Injection nozzle for internal combustion engines
DE29708369U1 (en) * 1997-05-09 1997-07-10 Fev Motorentech Gmbh & Co Kg Controllable injection valve for fuel injection on internal combustion engines
DE19729844A1 (en) * 1997-07-11 1999-01-14 Bosch Gmbh Robert Fuel injector
US6029913A (en) * 1998-09-01 2000-02-29 Cummins Engine Company, Inc. Swirl tip injector nozzle
AT413137B (en) * 1999-09-14 2005-11-15 Hoerbiger Ventilwerke Gmbh DIFFERENTIAL PRESSURE-CONTROLLED CHECK VALVE AND GAS INJECTOR
DE10212396A1 (en) * 2002-03-20 2003-10-09 Bosch Gmbh Robert Fuel injection system with 3/2-way valve

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR958772A (en) * 1950-03-17
CA487403A (en) * 1952-10-21 Edward Walter Nicolls Wilfrid Liquid fuel injection nozzles for internal combustion engines
NL28656C (en) *
GB529141A (en) * 1939-05-23 1940-11-14 Bernhard Bischof Fuel injection apparatus for internal combustion engines
DE879936C (en) * 1948-03-08 1953-06-18 Cav Ltd Fuel injector for internal combustion engines
GB762684A (en) * 1954-01-20 1956-12-05 David William Edgar Kyle Improvements in and relating to liquid fuel injection equipment for internal combustion engines
US2813752A (en) * 1956-11-13 1957-11-19 Studebaker Packard Corp Two stage fuel injection nozzle
DE2558790A1 (en) * 1975-12-24 1977-07-14 Bosch Gmbh Robert FUEL INJECTION NOZZLE FOR COMBUSTION MACHINES
US4167168A (en) * 1976-02-05 1979-09-11 Nippondenso Co., Ltd. Fuel injection apparatus
DE2711390A1 (en) * 1977-03-16 1978-09-21 Bosch Gmbh Robert FUEL INJECTOR
DE2711902A1 (en) * 1977-03-18 1978-09-21 Bosch Gmbh Robert FUEL INJECTOR
US4153205A (en) * 1977-10-19 1979-05-08 Allis-Chalmers Corporation Short seat fuel injection nozzle valve
DE2812519C2 (en) * 1978-03-22 1984-05-30 M.A.N. Maschinenfabrik Augsburg-Nürnberg AG, 8500 Nürnberg Fuel injection nozzle with needle lift control for direct injection internal combustion engines

Also Published As

Publication number Publication date
ZA832191B (en) 1984-11-28
BR8301565A (en) 1983-12-06
ES8403571A1 (en) 1984-03-16
ES521040A0 (en) 1984-03-16
EP0090296A1 (en) 1983-10-05
ATE21437T1 (en) 1986-08-15
AU1141783A (en) 1983-10-06
DE3365234D1 (en) 1986-09-18
AU551978B2 (en) 1986-05-15
CA1198022A (en) 1985-12-17
US4465231A (en) 1984-08-14
JPS58185971A (en) 1983-10-29

Similar Documents

Publication Publication Date Title
DE69938314T2 (en) Fuel injection valve
DE60015218T2 (en) Fuel injector
DE60126380T2 (en) Fuel injection valve
DE69922087T2 (en) fuel injector
DE2500644C2 (en) Fuel injection valve for internal combustion engines
DE3824467C2 (en)
DE1933489A1 (en) Fuel injection valve with electromagnetic actuation
DE2045556B2 (en) Device for injecting fuel into the cylinders of an internal combustion engine operating with pressure ignition
EP0959243A1 (en) Control valve for a fuel injector
DE60107794T2 (en) Fuel injection system
DE1807554C3 (en) Fuel injection device for internal combustion engines with pressure ignition
DE2833431A1 (en) FUEL INJECTION NOZZLE
EP0090296B1 (en) Needle-valve injection nozzle
DE19641824A1 (en) Fuel injection valve for internal combustion engines
DE10062959A1 (en) Fuel injection valve for internal combustion engines
CH671809A5 (en)
DE19611963A1 (en) Modulating flow diversion for a fuel injector
DE102005010453A1 (en) Fuel injection valve for internal combustion engines
DE10031574B4 (en) Pressure-controlled double-acting high-pressure injector
DE69720145T2 (en) Injector
EP1650427B1 (en) Fuel injection valve for internal combustion engines
EP1658427B1 (en) Fuel injection valve for internal combustion engines
DE3801929A1 (en) Fuel injection device
DE3117665C2 (en) Fuel injection valve for internal combustion engines
DE2726296A1 (en) FUEL INJECTOR

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): AT BE CH DE FR GB IT LI SE

ITCL It: translation for ep claims filed

Representative=s name: LENZI & C.

EL Fr: translation of claims filed
17P Request for examination filed

Effective date: 19840202

ITF It: translation for a ep patent filed

Owner name: LENZI & C.

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE CH DE FR GB IT LI SE

REF Corresponds to:

Ref document number: 21437

Country of ref document: AT

Date of ref document: 19860815

Kind code of ref document: T

REF Corresponds to:

Ref document number: 3365234

Country of ref document: DE

Date of ref document: 19860918

ET Fr: translation filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 19870325

Year of fee payment: 5

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AT

Effective date: 19880319

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19880320

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Effective date: 19880331

Ref country code: CH

Effective date: 19880331

BERE Be: lapsed

Owner name: DEERE & CY

Effective date: 19880331

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19881122

GBPC Gb: european patent ceased through non-payment of renewal fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19881130

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19881201

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Effective date: 19890331

EUG Se: european patent has lapsed

Ref document number: 83102731.3

Effective date: 19881206