EP0610584B1 - Fuel injection de vice with pilot- and main-injection of different fuels through a one-needle injection valve - Google Patents

Fuel injection de vice with pilot- and main-injection of different fuels through a one-needle injection valve Download PDF

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Publication number
EP0610584B1
EP0610584B1 EP19930120307 EP93120307A EP0610584B1 EP 0610584 B1 EP0610584 B1 EP 0610584B1 EP 19930120307 EP19930120307 EP 19930120307 EP 93120307 A EP93120307 A EP 93120307A EP 0610584 B1 EP0610584 B1 EP 0610584B1
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EP
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Prior art keywords
injection
valve
fuel
pump
bore
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EP19930120307
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German (de)
French (fr)
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EP0610584A1 (en
Inventor
Helmut Dipl.-Ing. Priesner
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MAN Truck and Bus Osterreich AG
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Steyr Nutzfahrzeuge AG
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M43/00—Fuel-injection apparatus operating simultaneously on two or more fuels, or on a liquid fuel and another liquid, e.g. the other liquid being an anti-knock additive
    • 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
    • F02M43/00—Fuel-injection apparatus operating simultaneously on two or more fuels, or on a liquid fuel and another liquid, e.g. the other liquid being an anti-knock additive
    • F02M43/04—Injectors peculiar thereto

Definitions

  • the invention relates to a fuel injection device for a pre-injection and main injection of different fuels via a single-needle injection valve, in which the pre-injection fuel is introduced into the injection valve from a low-pressure feed device, there through the spring chamber receiving the valve needle in the closing direction and through a channel in a cavity is fed into the valve needle and from there upstream via throttle bores in the nozzle antechamber and main injection fuel is subsequently introduced from an injection pump via an injection line or directly and a valve-internal channel into the nozzle antechamber behind the upstream pre-injection fuel, the valve needle being used to form the Cavity is drilled coaxially from its back to close to its tip, this cavity on the back by a partially immersed and with the pressure plate of the pressure Kfeder connected spacer bolt and can be filled with pre-injection fuel via a fill hole provided behind an annular lifting surface of the valve needle in the rear half thereof, via a feed channel into which a check valve which is only permeable in the feed direction is installed.
  • Such a fuel injection device is known from DE 30 12 418 A1, FIG. 2 and associated text.
  • An injection valve is used there, with a valve needle, in the cavity of which the check valve is installed directly.
  • This consists of a compression spring and a closing piston, through which the feed hole running in the spacer bolt can be closed against the feed direction in order to prevent backflow of pre-injection fuel located in the cavity when the main injection fuel becomes effective.
  • This known solution requires a relatively large valve needle, in which the cavity available for loading with pre-injection fuel is also comparatively severely restricted by the installation of the compression spring and the closing piston of the check valve. The amount of pre-injection fuel is therefore limited or must be adjusted accordingly by enlarging spaces outside the valve needle.
  • a fuel injection device similar to that discussed above is known from EP 0 064 146 B1.
  • a single-needle injection valve is used, with which a pre- and main injection of different fuels can be carried out.
  • the single-needle injection valve used here has a relatively complicated and therefore expensive structure. This complexity results from the design of the valve-internal supply paths for the pre-injection fuel and a relief valve built into the supply path for the main injection fuel.
  • the valve needle is hollow and open to the rear.
  • a bolt that connects to the pressure plate of the closing pressure spring, which extends from the front to close to the tip of the nozzle needle, has a longitudinal flattening on the outside, a transverse bore and a longitudinal bore for the passage of pre-injection fuel, and also a seat for the ball of a check valve forms.
  • the latter also has a compression spring acting on the ball, serves to prevent a backflow of fuel during the injection and is installed in the cavity of the valve needle in front of said bolt.
  • Throttle bores branch off from the area of the relevant receiving space, which enable the pre-injection fuel to be discharged into the nozzle antechamber.
  • the relief valve installed in the supply channel for main injection fuel is also relatively complicated; it consists of a compression spring and a special relief piston, which is realized by a stepped piston, which has a blind hole at the entrance and transverse holes leading away from it, as well as a shoulder, for which a corresponding seat is formed inside the valve is.
  • both the injection valves can be used as the injection pump can also be designed to be comparatively simple.
  • the additional structural effort for the external control means is in any case less expensive than a more complicated design of the injection valves and the injection pump.
  • these external control means namely the two solenoid valves in conjunction with the control device controlling their operation, enable the pre-injection fuel to be precisely pre-stored in terms of time and quantity in all operating areas of the internal combustion engines and to replenish the cavity with main injection fuel that is created in the subsequent line paths by closing an injection pump-side pressure valve , so that at the beginning of a pump piston-side delivery stroke in the injection valve a clearly defined stratification of pre-injection fuel and main injection fuel is given and in addition the line path previously given by the pressure line and the pump outlet space is completely filled with main injection fuel.
  • fuel is injected with exactly the amount of fuel that is displaced by the stroke of the pressure valve from the subsequent line paths.
  • the fuel injection device has an injection pump 1 with pump pistons 2 controlled by cams (not shown), each of which has conventional control grooves 3, 4 and oblique control edges 5 and can be rotated by a control device (also not shown) for power control.
  • the pump chambers 7, each of which can be filled with fluid such as oil or diesel fuel from a supply device via a laterally opening control bore 6, are adjoined by a pump outlet chamber 8 and an injection line 11 connected to a supply channel 10 internally provided with a single-needle injection valve 9. If the single-needle injection valve 9 is combined with the injection pump 1 to form a pump nozzle member, the injection line 11 is omitted.
  • connection bore 12 between each pump chamber 7 and pump outlet chamber 8 is provided on the rear with a conical extension 13, which serves as a seat for a in the pump outlet chamber 8 low-pressure valve 14 is used, which is acted upon in the closing direction by a pressure spring 15 also installed in the pump outlet chamber 8.
  • the injection pump according to the invention only serves to build up pressure and to advance the amount of main injection fuel coming in for injection, which is successively supplied to the line paths 8, 11, 10 adjoining the pressure valve 14.
  • Each pressure valve 14 acts as a pressure piston during the pump piston stroke, which pushes the fuel column behind it by means of its stroke movement and at the same time blocks a filling bore 16 opening laterally into the pump outlet space 8, via which after each injection process has ended and the pressure valve 14 has returned to its closed position
  • the resulting cavity, corresponding to the amount of fuel injected, in said conduits 8, 11, 10 can be refilled with main injection fuel from a low-pressure feed device 17, controlled shortly before or after completion of a pre-injection fuel refill via a magnetic valve 19 built into the external feed line 18 .
  • Each single-needle injection valve 9 assigned to a cylinder of the internal combustion engine has a hollow valve needle 20, the cavity 21 of which is closed on the rear side can be filled with pre-injection fuel from the outside via a filling bore 22, specifically via an internal valve consisting of parts 23/1, 23 / 2, 23/3, 23/4, 23/5, 23/6 composing feed channel 23, in which a check valve 24 which is only permeable in the feed direction is installed.
  • the latter serves to prevent a backflow of pre-injection fuel during the injection.
  • the cavity 21 is connected via holes 25 located near the valve needle tip 27 to the nozzle antechamber 26 which extends around the front part of the valve needle 20 and widens at the rear.
  • the valve needle 20 is preferably drilled from its rear coaxially to almost its tip 27.
  • This cavity 21 designed in this way is preferably closed on the rear by a partially immersed spacer bolt 28, which establishes the connection between the valve needle 20 and a pressure plate 29, on which a compression spring 30 acting on the valve needle 20 in the closing direction is supported at the front.
  • This compression spring 30 presses the valve needle 20 in the closed position against a conical valve seat 31, in front of which nozzle bores 32 open into the combustion chamber.
  • annular lifting surface 33 approximately through the middle of its longitudinal extension at the transition between its smaller diameter front and larger diameter rear section, through which the valve needle with correspondingly acting in the nozzle vestibule 26 fuel pressure can be raised in the open position.
  • the filling bore 22 is preferably provided behind the annular lifting surface 33 of the valve needle 20 in the rear half thereof and is designed as a transverse bore which extends from an annular groove 34 provided on the outside of the valve needle 20, which communicates with the supply channel 23 in each valve needle position.
  • the latter in turn preferably includes the spring chamber receiving the compression spring 30 (section 23/2), an annular gap (section 23/3) around the pressure plate 29 and the spacer bolt 28, and then sits down with a transverse channel (section 23/4), one Vertical bore (section 23/5), in which the check valve 24 is installed, and continues with an oblique bore (section 23/6), the latter opening laterally at the level of the filling bore 22 into the receiving bore 35 guiding the valve needle 20.
  • the aim should be that the check valve 24 is installed in the valve-internal feed channel 23 as close as possible before the junction point in the receiving bore 35.
  • the valve-internal feed channel 23 can be supplied with pre-injection fuel from a low-pressure feed device 36 via a feed line 37, in which a cyclically controllable solenoid valve 38 is built in for the exact metering in terms of time and quantity.
  • the main injection fuel supply channel 10 opening into the nozzle antechamber 26 is formed internally in the valve only by bore sections communicating with one another without any internals.
  • the two solenoid valves 19, 38 are preferably combined in a common valve block 39 which is installed in the two supply lines 18, 37 running over it.
  • the two solenoid valves 19, 38 can be controlled by an electronic control device 40, which operates on the basis of their supplied angle of rotation signals ⁇ of the crankshaft of the internal combustion engine or a camshaft controlling the gas exchange valves thereof or the pump pistons 2 of the injection pump 1 and in which the opening and closing times of the two solenoid valves 19, 38 are stored as values dependent on the angle of rotation.
  • Each of the two fuels is provided in its own storage tank 41, 42 and is made from it by the associated low-pressure feed device 17 or 36 eligible.
  • Each of the latter consists of a feed pump 17/1 or 36/1 and a pressure relief valve 17/2 or 36/2, which limits their delivery pressure to approximately 2 to 4 bar.
  • diesel fuel can be used as the ignitable pilot injection fuel and a diesel water emulsion or ethanol can be used as the ignition carrier main injection fuel.
  • the pump chambers 7 of the injection pump can also be supplied with the appropriate fuel from the corresponding low-pressure feed device 36.
  • the cavities given in the injection system are first refilled.
  • the two fuels are basically stratified in such a way that pre-injection fuel is present in the vicinity of the nozzle bores 32 in the nozzle vestibule 26 and the main injection fuel is stratified behind it, that is to say at a greater distance.
  • the line paths 8, 11 adjoining the pressure valve 14 and all the channels inside the valve are depressurized. This state occurs when the pressure in the pump chamber 7 collapses at the end of the pump piston stroke and, as a result, the valve needle 20 closes and the pressure valve 14 returns to its closed position.
  • the solenoid valve 38 is first opened from the control device 40, so that pre-injection fuel can be introduced into the injection valve 36 through the low-pressure feed device 36, specifically via the feed channel 23 with its parts 23/1, 23/2, 23/3, 23 / 4, 23/5, 23/6, as a result of which the fuel located in the cavity 21 of the valve needle 20 is discharged into the nozzle antechamber 26 via the throttle bores 25 - while displacing the main injection fuel still located in the nozzle antechamber 26 back into the supply channel 10.
  • the solenoid valve 38 is closed again by the control device 40 and the pre-injection fuel pre-storage is thus ended.
  • the solenoid valve 19 is opened, so that then main injection fuel from the low-pressure feed device 17 via the feed line 18 and the filling bore 16 for filling of the cavity given in the conduction paths 8, 11 and 10 can be conveyed.
  • the main injection fuel in the valve-internal supply channel 10 is subsequently added to the pre-injection fuel which is already upstream of the latter.
  • the solenoid valve 18 is closed again by the control device 40.
  • the opening time for the solenoid valve 18 is so large that all cavities can always be filled. The sequence described also leads to an exact metering if the set amount was smaller than the desired pre-injection fuel amount.

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

Description

Die Erfindung betrifft eine Kraftstoffeinspritzvorrichtung für eine Vor- und Haupteinspritzung unterschiedlicher Kraftstoffe über ein Einnadel-Einspritzventil, bei der Voreinspritzkraftstoff von einer Niederdruck-Speiseeinrichtung her in das Einspritzventil eingeleitet, dort durch den die Ventilnadel in Schließrichtung beaufschlagende Druckfeder aufnehmenden Federraum hindurch und über einen Kanal in einen Hohlraum in der Ventilnadel eingespeist sowie von dort über nahe deren Sitz gegebene Drosselbohrungen im Düsenvorraum vorgelagert und Haupteinspritzkraftstoff anschließend von einer Einspritzpumpe über eine Einspritzleitung oder direkt und einen ventilinternen Kanal ebenfalls in den Düsenvorraum hinter den vorgelagerten Voreinspritzkraftstoff eingeleitet wird, wobei die Ventilnadel zur Bildung des Hohlraumes von ihrer Rückseite her koaxial bis nahe zu ihrer Spitze aufgebohrt ist, dieser Hohlraum rückseitig durch einen partiell eintauchenden und mit dem Druckteller der Druckfeder verbundenen Distanzbolzen verschlossen und über eine hinter einer ringförmigen Hubfläche der Ventilnadel in deren rückwärtiger Hälfte gegebene Füllbohrung mit Voreinspritzkraftstoff füllbar ist, über einen Zuführkanal, in den ein nur in Speiserichtung durchlässiges Rückschlagventil eingebaut ist.The invention relates to a fuel injection device for a pre-injection and main injection of different fuels via a single-needle injection valve, in which the pre-injection fuel is introduced into the injection valve from a low-pressure feed device, there through the spring chamber receiving the valve needle in the closing direction and through a channel in a cavity is fed into the valve needle and from there upstream via throttle bores in the nozzle antechamber and main injection fuel is subsequently introduced from an injection pump via an injection line or directly and a valve-internal channel into the nozzle antechamber behind the upstream pre-injection fuel, the valve needle being used to form the Cavity is drilled coaxially from its back to close to its tip, this cavity on the back by a partially immersed and with the pressure plate of the pressure Kfeder connected spacer bolt and can be filled with pre-injection fuel via a fill hole provided behind an annular lifting surface of the valve needle in the rear half thereof, via a feed channel into which a check valve which is only permeable in the feed direction is installed.

Eine solche Kraftstoffeinspritzvorrichtung ist aus der DE 30 12 418 Al, Fig. 2 und zugehörigem Text, bekannt. Dort kommt ein Einspritzventil zur Anwendung, mit einer Ventilnadel, in deren Hohlraum unmittelbar das Rückschlagventil eingebaut ist. Dieses besteht aus einer Druckfeder und einem Schließkolben, durch den die im Distanzbolzen verlaufende Zuführbohrung entgegen Speiserichtung verschließbar ist, um ein Rückströmen von im Hohlraum befindlichem Voreinspritzkraftstoff bei Wirksamwerden des Haupteinspritzkraftstoffes zu verhindern. Diese bekannte Lösung setzt eine verhältnismäßig stark dimensionierte Ventilnadel voraus, in der zudem der für eine Ladung mit Voreinspritzkraftstoff zur Verfügung stehende Hohlraum durch den Einbau der Druckfeder und des Schließkolbens des Rückschlagventiles vergleichsweise stark eingeschränkt ist. Die Menge an Voreinspritzkraftstoff ist daher beschränkt oder muß durch Vergrößerung außerhalb der Ventilnadel gegebener Räume entsprechend eingestellt werden.Such a fuel injection device is known from DE 30 12 418 A1, FIG. 2 and associated text. An injection valve is used there, with a valve needle, in the cavity of which the check valve is installed directly. This consists of a compression spring and a closing piston, through which the feed hole running in the spacer bolt can be closed against the feed direction in order to prevent backflow of pre-injection fuel located in the cavity when the main injection fuel becomes effective. This known solution requires a relatively large valve needle, in which the cavity available for loading with pre-injection fuel is also comparatively severely restricted by the installation of the compression spring and the closing piston of the check valve. The amount of pre-injection fuel is therefore limited or must be adjusted accordingly by enlarging spaces outside the valve needle.

Auch der ventilinterne Haupteinspritzkraftstoff-Zuführkanal ist - wie Fig. 2 zeigt-bei der bekannten Lösung nicht frei von Einbauten. Vielmehr enthält dieser ein eingangs eingebautes Stabfilter.Even the main fuel injection channel inside the valve is not free of internals in the known solution, as shown in FIG. 2. Rather, it contains a rod filter installed at the beginning.

Über die Zuführung, insbesondere zeit- und mengenmäßige Zumessung des Voreinspritzkraftstoffes zum Einspritzventil ist in diesem Vorhalt nichts ausgesagt. Hinsichtlich der Zumessung des Haupteinspritzkraftstoffes ist ausgesagt, daß hierfür eine Einspritzpumpe vorgesehen ist.In this provision, nothing is said about the supply, in particular the timing and quantity of the pilot fuel to the injection valve. With regard to the metering of the main injection fuel, it is stated that an injection pump is provided for this.

Eine der vorstehend diskutierten ähnliche Kraftstoffeinspritzvorrichtung ist aus der EP 0 064 146 B1 bekannt. Auch hier ist ein Einnadel-Einspritzventil verwendet, mit dem eine Vor- und Haupteinspritzung unterschiedlicher Kraftstoffe durchführbar ist. Das dabei verwendete Einnadel-Einspritzventil besitzt jedoch einen relativ komplizierten und damit teuren Aufbau. Diese Komplexität resultiert aus der Gestaltung der ventilinternen Zuführwege für den Voreinspritzkraftstoff und einem in den Zuführweg für den Haupteinspritzkraftstoff eingebauten Entlastungsventil. Dabei ist die Ventilnadel hohl ausgebildet und nach hinten offen. In diesen Hohlraum taucht ein die Verbindung zum Druckteller der Schließdruckfeder herstellender Bolzen ein, der vorne bis nahe zur Spitze der Düsennadel reicht, außen eine Längsabflachung, ferner eine Querbohrung und eine Längsbohrung für die Durchleitung von Voreinspritzkraftstoff aufweist und außerdem einen Sitz für die Kugel eines Rückschlagventiles bildet. Letzteres weist außerdem eine die Kugel beaufschlagende Druckfeder auf, dient zur Verhinderung eines Kraftstoffrückflusses während der Einspritzung und ist vor besagtem Bolzen in den Hohlraum der Ventilnadel eingebaut. Vom Bereich des diesbezüglichen Aufnahmeraumes zweigen Drosselbohrungen ab, die die Ausleitung des Voreinspritzkraftstoffes in den Düsenvorraum ermöglichen. Auch das in den Zuführkanal für Haupteinspritzkraftstoff eingebaute Entlastungsventil ist relativ kompliziert, es besteht aus einer Druckfeder und einem speziellen Entlastungskolben, der durch einen Stufenkolben realisiert ist, welcher eingangs eine Sacklochbohrung und davon abgehende Querbohrungen sowie eine Schulter aufweist, für die ventilintern ein entsprechender Sitz ausgebildet ist.A fuel injection device similar to that discussed above is known from EP 0 064 146 B1. Here too, a single-needle injection valve is used, with which a pre- and main injection of different fuels can be carried out. However, the single-needle injection valve used here has a relatively complicated and therefore expensive structure. This complexity results from the design of the valve-internal supply paths for the pre-injection fuel and a relief valve built into the supply path for the main injection fuel. The valve needle is hollow and open to the rear. Dipped into this cavity is a bolt that connects to the pressure plate of the closing pressure spring, which extends from the front to close to the tip of the nozzle needle, has a longitudinal flattening on the outside, a transverse bore and a longitudinal bore for the passage of pre-injection fuel, and also a seat for the ball of a check valve forms. The latter also has a compression spring acting on the ball, serves to prevent a backflow of fuel during the injection and is installed in the cavity of the valve needle in front of said bolt. Throttle bores branch off from the area of the relevant receiving space, which enable the pre-injection fuel to be discharged into the nozzle antechamber. The relief valve installed in the supply channel for main injection fuel is also relatively complicated; it consists of a compression spring and a special relief piston, which is realized by a stepped piston, which has a blind hole at the entrance and transverse holes leading away from it, as well as a shoulder, for which a corresponding seat is formed inside the valve is.

Diese bekannte Lösung läßt zwar eine exakte Dosierung der Vorlagerungskraftstoffmenge zu, muß jedoch außer den bereits erwähnten Nachteilen noch andere Nachteile in Kauf nehmen, auf die nachstehend eingegangen ist. Die Vorlagerungskraftstoffmenge ist aufgrund der Einspritzventilgestaltung konstruktiv festgelegt und daher nicht variierbar. Außerdem bringt der düsenseitige Einbau des Entlastungsventiles zusätzliche Druckverluste und Schadvolumina mit sich. Ferner muß der Druck in der Einspritzleitung nach Beendigung einer Einspritzung niedriger sein als der Öffnungsdruck des düsenseitigen Entlastungsventiles. Dies bedeutet entweder einen aus Platzgründen schwer darstellbaren hohen Öffnungsdruck für dieses, verbunden mit hohem Druckverlust, oder ein einspritzpumpenseitig überentlastendes Druckventil mit den für ein solches aus anderen Einspritzvorrichtungen bekannten Nachteilen wie Kavitation, Streuung von Einspritzmenge und -beginn und dergleichen.Although this known solution allows an exact metering of the amount of pre-storage fuel, it has to accept other disadvantages in addition to the disadvantages already mentioned, which are discussed below. The amount of pre-stored fuel is structurally determined due to the injection valve design and therefore cannot be varied. In addition, the installation of the relief valve on the nozzle side entails additional pressure losses and damage volumes. Furthermore, the pressure in the injection line after completion of an injection must be lower than the opening pressure of the nozzle-side relief valve. This means either a high opening pressure for this, which is difficult to represent due to space constraints, combined with a high pressure loss, or a pressure relief valve on the injection pump side, with the disadvantages known from such injectors such as cavitation, scattering of injection quantity and start and the like.

Es ist daher Aufgabe der Erfindung, eine Kraftstoffeinspritzvorrichtung der eingangs genannten Art so zu verbessern, daß einfachere und damit billigere Einnadel-Einspritzventile verwendbar sind, außerdem in allen Lastbereichen der Brennkraftmaschine eine variable, mengenmäßig aber exakt angepaßte Dosierung des Vor- und Haupteinspritzkraftstoffes möglich ist und problematische Zustände nach Beendigung eines Einspritzvorganges vermeidbar sind.It is therefore an object of the invention to improve a fuel injector of the type mentioned in such a way that simpler and therefore cheaper single-needle injectors can be used, and in addition, variable, quantitative but precisely adjusted metering of the pilot and main injection fuel is possible in all load ranges of the internal combustion engine problematic conditions after the end of an injection process can be avoided.

Diese Aufgabe ist erfindungsgemäß dadurch gelöst,

  • daß die Füllbohrung als Querbohrung ausgebildet ist, die von einer außen an der Ventilnadel gegebenen Ringnut abgeht, welche in jeder Ventilnadelstellung mit dem Zuführkanal kommuniziert,
  • daß das Rückschlagventil im ventilinternen Zuführkanal möglichst nahe vor dessen Einmündung in die die Ventilnadel führende Aufnahmebohrung hingerückt eingebaut ist,
  • daß der ventilinterne Haupteinspritzkraftstoff-Zuführkanal nur durch miteinander kommunizierende Bohrungsabschnitte ohne Einbauten gebildet ist,
  • daß zur zeit- und mengenmäßig exakten Zumessung des Voreinspritzkraftstoffes in der externen Zuleitung ein steuerbares Magnetventil eingebaut ist,
  • daß sich an jeden Pumpenraum der Einspritzpumpe ein ein Druckventil und eine Druckfeder aufnehmender Pumpenausgangsraum und daran entweder über die Einspritzleitung oder direkt der einspritzventilinterne Zuführkanal anschließt, und
  • daß die Einspritzpumpe nur zur Druckerzeugung und zum Vorschub der dem Druckventil in den anschließenden Leitungswegen nachgelagerten Kraftstoffsäule dient, wobei jedes Druckventil beim Pumpenkolben-Hub als Druckkolben wirkt und gleichzeitig eine seitlich in den Pumpenausgangsraum einmündende Füllbohrung absperrt, über die nach Beendigung jedes Einspritzvorganges und Rückführung des Druckventils in Schließstellung der dadurch entstehende, der eingespritzten Kraftstoffmenge entsprechende Hohlraum in besagten Leitungswegen von einer Niederdruck-Speiseeinrichtung her wieder mit Haupteinspritzkraftstoff auffüllbar ist, und zwar gesteuert kurz vor oder nach Beendigung der Voreinspritzkraftstoff-Nachfüllung über ein in die Zuleitung eingebautes Magnetventil.
According to the invention, this object is achieved by
  • that the filling bore is designed as a transverse bore which extends from an annular groove provided on the outside of the valve needle and which communicates with the feed channel in each valve needle position,
  • that the check valve is installed in the valve-internal feed channel as close as possible before its junction in the receiving bore guiding the valve needle,
  • that the valve-internal main injection fuel supply channel is formed only by bore sections communicating with one another without internals,
  • that a controllable solenoid valve is installed in the external supply line for exact metering of the pre-injection fuel,
  • that each pump chamber of the injection pump has a pressure valve and a compression spring receiving pump outlet chamber and is connected either via the injection line or directly to the injection valve internal feed channel, and
  • that the injection pump is only used to generate pressure and to advance the fuel column downstream of the pressure valve in the subsequent conduit paths, with each pressure valve acting as a pressure piston during the pump piston stroke and at the same time shutting off a filling bore which opens laterally into the pump outlet space and via which after the end of each injection process and return of the Pressure valve in the closed position of the resulting cavity corresponding to the amount of fuel injected in said conduit paths from a low-pressure feed device can be refilled with main injection fuel, controlled shortly before or after completion of the pre-injection fuel refill via a solenoid valve built into the supply line.

Durch das erfindungsgemäße Verlegen der für die zeit- und mengenmäßig exakte Zumessung des Voreinspritzkraftstoffs verantwortlichen Steuerungsorgane und jener Steuerungsorgane, die für das zeit- und mengenmäßig exakte Wiederauffüllen des nach Beendigung eines Einspritzvorganges gegebenen Hohlraumes in den Haupteinspritzkraftstoff-Leitungswegen verantwortlich sind, können sowohl die Einspritzventile als auch die Einspritzpumpe konstruktiv vergleichsweise einfach gestaltet sein. Der bauliche Mehraufwand für die externen Steuermittel ist kostenmäßig jedenfalls geringer anzusetzen als eine kompliziertere Gestaltung der Einspritzventile und der Einspritzpumpe. Außerdem ermöglichen diese externen Steuermittel, nämlich die beiden Magentventile in Verbindung mit der deren Betrieb steuernden Steuereinrichtung, eine in allen Betriebsbereichen der Brennkraftmaschinen zeit- und mengenmäßig exakte Vorlagerung des Voreinspritzkraftstoffes sowie Wiederauffüllung des durch das Schließen eines einspritzpumpenseitigen Druckventiles in den nachfolgenden Leitungswegen entstehenden Hohlraumes mit Haupteinspritzkraftstoff, so daß am Beginn eines pumpenkolbenseitigen Förderhubes im Einspritzventil eine eindeutig definierte Schichtung von Voreinspritzkraftstoff und Haupteinspritzkraftstoff gegeben und außerdem der davor durch die Druckleitung und den Pumpenausgangsraum gegebene Leitungsweg vollständig mit Haupteinspritzkraftstoff gefüllt ist. Zur Einspritzung kommt dann bei einem pumpenkolbenseitigen Förderhub exakt jene Kraftstoffmenge, die durch den Hub des Druckventiles aus den anschließenden Leitungswegen verdrängt wird. Kavitations-Schäden, eine Streuung von Einspritzmenge und -beginn und zu geringer Einspritzdruck, wie sie in nachteiliger Form bei der eingangs diskutierten bekannten Kraftstoffeinspritzvorrichtung auftreten können, ergeben sich mit der erfindungsgemäßen Kraftstoffeinspritzvorrichtung aufgrund deren Gestaltung nicht.Due to the inventive laying of the control members responsible for the exact metering of the pre-injection fuel in terms of time and those control members responsible for the exact replenishment of the cavity in the main injection fuel line paths given after the end of an injection process, both the injection valves can be used as the injection pump can also be designed to be comparatively simple. The additional structural effort for the external control means is in any case less expensive than a more complicated design of the injection valves and the injection pump. In addition, these external control means, namely the two solenoid valves in conjunction with the control device controlling their operation, enable the pre-injection fuel to be precisely pre-stored in terms of time and quantity in all operating areas of the internal combustion engines and to replenish the cavity with main injection fuel that is created in the subsequent line paths by closing an injection pump-side pressure valve , so that at the beginning of a pump piston-side delivery stroke in the injection valve a clearly defined stratification of pre-injection fuel and main injection fuel is given and in addition the line path previously given by the pressure line and the pump outlet space is completely filled with main injection fuel. For a pump stroke on the pump piston side, fuel is injected with exactly the amount of fuel that is displaced by the stroke of the pressure valve from the subsequent line paths. Cavitation damage, a spread of the injection quantity and start and an injection pressure that is too low, such as can occur in a disadvantageous form in the known fuel injection device discussed at the outset, do not occur with the fuel injection device according to the invention due to its design.

Vorteilhafte Ausgestaltungen und Weiterbildungen der erfindungsgemäßen Kraftstoffeinspritzvorrichtung sind in den Unteransprüchen gekennzeichnet.Advantageous refinements and developments of the fuel injection device according to the invention are characterized in the subclaims.

Nachstehend ist die erfindungsgemäße Kraftstoffeinspritzvorrichtung anhand eines in der Zeichnung dargestellten Ausführungsbeispieles näher erläutert.The fuel injection device according to the invention is explained in more detail below on the basis of an exemplary embodiment shown in the drawing.

Die Kraftstoffeinspritzvorrichtung weist eine Einspritzpumpe 1 mit von nicht dargestellten Nocken gesteuerten Pumpenkolben 2 auf, die jeweils übliche Steuernuten 3, 4 und schräge Steuerkanten 5 aufweisen sowie für Leistungsregelung durch eine ebenfalls nicht dargestellte Steuervorrichtung verdrehbar sind. An die jeweils über eine seitlich einmündende Steuerbohrung 6 mit Fluid, wie Öl oder Dieselkraftstoff von einer Versorgungseinrichtung her füllbaren Pumpenräume 7 schließt sich ausgangsjeweils ein Pumpenausgangsraum 8 und daran eine mit einem intern eines Einnadel-Einspritzventiles 9 gegebenen Zuführkanal 10 verbundene Einspritzleitung 11 an. Wenn das Einnadel-Einspritzventil 9 mit der Einspritzpumpe 1 zu einem Pumpen-Düsen-Organ vereinigt ist, entfällt die Einspritzleitung 11. Die zwischen jedem Pumpenraum 7 und Pumpenausgangsraum 8 gegebene Verbindungsbohrung 12 ist rückseitig mit einer kegligen Erweiterung 13 versehen, die als Sitz für ein im Pumpenausgangsraum 8 leckagearm eingebautes Druckventil 14 dient, welches in Schließrichtung durch eine ebenfalls in den Pumpenausgangsraum 8 eingebaute Druckfeder 15 beaufschlagt ist. Im Gegensatz zu herkömmlichen Einspritzpumpen, bei denen durch den Pumpenkolben-Hub der geförderte Kraftstoff unmittelbar einem Einspritzventil zugeführt wird, dient die erfindungsgemäße Einspritzpumpe nur zum Druckaufbau und zum Vorschub der zur Einspritzung kommenden Menge an Haupteinspritzkraftstoff, welcher sukzessive den sich am Druckventil 14 anschließenden Leitungswegen 8, 11, 10 zugeführt wird. Dabei wirkt jedes Druckventil 14 beim Pumpenkolben-Hub als Druckkolben, der durch seine Hubbewegung die dahinter anstehende Kraftstoffsäule voranschiebt und gleichzeitig eine seitlich in den Pumpenausgangsraum 8 einmündende Füllbohrung 16 absperrt, über die nach Beendigung jedes Einspritzvorganges und Rückführung des Druckventils 14 in dessen Schließstellung der dadurch entstehende, der eingespritzten Kraftstoffmenge entsprechende Hohlraum in besagten Leitungswegen 8, 11, 10 von einer Niederdruck-Speiseeinrichtung 17 her wieder mit Haupteinspritzkraftstoff auffüllbar ist, und zwar gesteuert kurz vor oder nach Beendigung einer Voreinspritzkraftstoff-Nachfüllung über ein in die externe Zuleitung 18 eingebautes Magentventil 19.The fuel injection device has an injection pump 1 with pump pistons 2 controlled by cams (not shown), each of which has conventional control grooves 3, 4 and oblique control edges 5 and can be rotated by a control device (also not shown) for power control. The pump chambers 7, each of which can be filled with fluid such as oil or diesel fuel from a supply device via a laterally opening control bore 6, are adjoined by a pump outlet chamber 8 and an injection line 11 connected to a supply channel 10 internally provided with a single-needle injection valve 9. If the single-needle injection valve 9 is combined with the injection pump 1 to form a pump nozzle member, the injection line 11 is omitted. The connection bore 12 between each pump chamber 7 and pump outlet chamber 8 is provided on the rear with a conical extension 13, which serves as a seat for a in the pump outlet chamber 8 low-pressure valve 14 is used, which is acted upon in the closing direction by a pressure spring 15 also installed in the pump outlet chamber 8. In contrast to conventional injection pumps, in which the delivered fuel is fed directly to an injection valve through the pump piston stroke, the injection pump according to the invention only serves to build up pressure and to advance the amount of main injection fuel coming in for injection, which is successively supplied to the line paths 8, 11, 10 adjoining the pressure valve 14. Each pressure valve 14 acts as a pressure piston during the pump piston stroke, which pushes the fuel column behind it by means of its stroke movement and at the same time blocks a filling bore 16 opening laterally into the pump outlet space 8, via which after each injection process has ended and the pressure valve 14 has returned to its closed position The resulting cavity, corresponding to the amount of fuel injected, in said conduits 8, 11, 10 can be refilled with main injection fuel from a low-pressure feed device 17, controlled shortly before or after completion of a pre-injection fuel refill via a magnetic valve 19 built into the external feed line 18 .

Jedes einem Zylinder der Brennkraftmaschine zugeordnete Einnadel-Einspritzventil 9 weist eine hohl ausgebildete Ventilnadel 20 auf, deren rückseitig verschlossener Hohlraum 21 über eine Füllbohrung 22 von außen her mit Voreinspritzkraftstoff füllbar ist, und zwar über einen ventilinternen, sich aus Teilen 23/1, 23/2, 23/3, 23/4, 23/5, 23/6 zusammensetzenden Zuführkanal 23, in den ein nur in Speiserichtung durchlässiges Rückschlagventil 24 eingebaut ist.Letzteres dient dazu, ein Rückströmen von Voreinspritzkraftstoff während der Einspritzung zu verhindern. Der Hohlraum 21 steht über nahe der Ventilnadelspitze 27 gelegene Bohrungen 25 mit dem sich um den vorderen Teil der Ventilnadel 20 erstreckenden und hinten erweitenden Düsenvorraum 26 in Verbindung.Each single-needle injection valve 9 assigned to a cylinder of the internal combustion engine has a hollow valve needle 20, the cavity 21 of which is closed on the rear side can be filled with pre-injection fuel from the outside via a filling bore 22, specifically via an internal valve consisting of parts 23/1, 23 / 2, 23/3, 23/4, 23/5, 23/6 composing feed channel 23, in which a check valve 24 which is only permeable in the feed direction is installed. The latter serves to prevent a backflow of pre-injection fuel during the injection. The cavity 21 is connected via holes 25 located near the valve needle tip 27 to the nozzle antechamber 26 which extends around the front part of the valve needle 20 and widens at the rear.

Zur Bildung des Hohlraumes 21 ist die Ventilnadel 20 vorzugsweise von ihrer Rückseite her koaxial bis nahezu ihrer Spitze 27 aufgebohrt. Dieser so gestaltete Hohlraum 21 ist rückseitig vorzugsweise durch einen partiell eintauchenden Distanzbolzen 28 verschlossen, welcher die Verbindung zwischen der Ventilnadel 20 und einem Druckteller 29 herstellt, an dem eine die Ventilnadel 20 in Schließrichtung beaufschlagende Druckfeder 30 vorne abgestützt ist. Diese Druckfeder 30 drückt die Ventilnaddel 20 in Schließposition an einen kegligen Ventilsitz 31, vor welchem Düsenbohrungen 32 in den Brennraum ausmünden. An der Ventilnadel 20 ist etwa in der Mitte ihrer Längserstreckung am Übergang zwischen ihrem durchmesserschwächeren vorderen und durchmessergrößeren hinteren Abschnitt eine ringförmige Hubfläche 33 gegeben, durch die die Ventilnadel bei entsprechend im Düsenvorraum 26 wirkenden Kraftstoffdruck in Öffnungsstellung anhebbar ist.To form the cavity 21, the valve needle 20 is preferably drilled from its rear coaxially to almost its tip 27. This cavity 21 designed in this way is preferably closed on the rear by a partially immersed spacer bolt 28, which establishes the connection between the valve needle 20 and a pressure plate 29, on which a compression spring 30 acting on the valve needle 20 in the closing direction is supported at the front. This compression spring 30 presses the valve needle 20 in the closed position against a conical valve seat 31, in front of which nozzle bores 32 open into the combustion chamber. At the valve needle 20 there is an annular lifting surface 33, approximately through the middle of its longitudinal extension at the transition between its smaller diameter front and larger diameter rear section, through which the valve needle with correspondingly acting in the nozzle vestibule 26 fuel pressure can be raised in the open position.

Die Füllbohrung 22 ist vorzugsweise hinter der ringförmigen Hubfläche 33 der Ventilnadel 20 in deren rückwärtiger Hälfte gegeben und als Querbohrung ausgebildet, die von einer außen an der Ventilnadel 20 gegebenen Ringnut 34 abgeht, welche in jeder Ventilnadelstellung mit dem Zuführkanal 23 kommuniziert. Letzterer wiederum schließt vorzugsweise den die Druckfeder 30 aufnehmenden Federraum (Abschnitt 23/2), einen Ringspalt (Abschnitt 23/3) um den Druckteller 29 und den Distanzbolzen 28 ein, und setzt sich dann mit einem Querkanal (Abschnitt 23/4), einer Vertikalbohrung (Abschnitt 23/5), in die das Rückschlagventil 24 eingebaut ist, und mit einer Schrägbohrung (Abschnitt 23/6) fort, welch letztere in Höhe der Füllbohrung 22 seitlich in die die Ventilnadel 20 führende Aufnahmebohrung 35 einmündet. Grundsätzlich ist dabei anzustreben, daß das Rückschlagventil 24 im ventilinternen Zuführkanal 23 möglichst nahe vor dessen Einmündungsstelle in die Aufnahmebohrung 35 eingebaut ist.The filling bore 22 is preferably provided behind the annular lifting surface 33 of the valve needle 20 in the rear half thereof and is designed as a transverse bore which extends from an annular groove 34 provided on the outside of the valve needle 20, which communicates with the supply channel 23 in each valve needle position. The latter in turn preferably includes the spring chamber receiving the compression spring 30 (section 23/2), an annular gap (section 23/3) around the pressure plate 29 and the spacer bolt 28, and then sits down with a transverse channel (section 23/4), one Vertical bore (section 23/5), in which the check valve 24 is installed, and continues with an oblique bore (section 23/6), the latter opening laterally at the level of the filling bore 22 into the receiving bore 35 guiding the valve needle 20. Basically, the aim should be that the check valve 24 is installed in the valve-internal feed channel 23 as close as possible before the junction point in the receiving bore 35.

Der ventilinterne Zuführkanal 23 ist von einer Niederdruck-Speiseeinrichtung 36 her über eine Zuleitung 37 mit Voreinspritzkraftstoff versorgbar, in welche zur zeit- und mengenmäßig exakten Zumessung desselben ein taktweise steuerbares Magnetventil 38 eingebaut ist.The valve-internal feed channel 23 can be supplied with pre-injection fuel from a low-pressure feed device 36 via a feed line 37, in which a cyclically controllable solenoid valve 38 is built in for the exact metering in terms of time and quantity.

Der in den Düsenvorraum 26 ausmündende Haupteinspritzkraftstoff-Zuführkanal 10 ist ventilintern nur durch miteinander kommunizierende Bohrungsabschnitte ohne jedwede Einbauten gebildet.The main injection fuel supply channel 10 opening into the nozzle antechamber 26 is formed internally in the valve only by bore sections communicating with one another without any internals.

Die beiden Magnetventile 19, 38 sind vorzugsweise in einem gemeinsamen Ventilblock 39 zusammengefaßt, der in die beiden über ihn laufenden Zuführleitungen 18, 37 eingebaut ist. Die beiden Magnetventile 19, 38 sind von einer elektronischen Steuereinrichtung 40 her steuerbar, die auf der Basis ihr zugeführter Drehwinkelsignale φ der Kurbelwelle der Brennkraftmaschine oder einer die Gaswechselventile derselben oder die Pumpenkolben 2 der Einspritzpumpe 1 steuernden Nockenwelle arbeitet und in der die Öffnungs- und Schließzeitpunkte der beiden Magnetventile 19, 38 als drehwinkelabhängige Werte abgespeichert sind.The two solenoid valves 19, 38 are preferably combined in a common valve block 39 which is installed in the two supply lines 18, 37 running over it. The two solenoid valves 19, 38 can be controlled by an electronic control device 40, which operates on the basis of their supplied angle of rotation signals φ of the crankshaft of the internal combustion engine or a camshaft controlling the gas exchange valves thereof or the pump pistons 2 of the injection pump 1 and in which the opening and closing times of the two solenoid valves 19, 38 are stored as values dependent on the angle of rotation.

Jeder der beiden Kraftstoffe wird in einem eigenen Vorratstank 41, 42 bereitgestellt und ist aus diesen durch die zugehörige Niederdruck-Speiseeinrichtung 17 bzw. 36 förderbar. Jede der letzteren besteht aus einer Förderpumpe 17/1 bzw. 36/1 und einem deren Förderdruck auf etwa 2 bis 4 bar begrenzenden Druckbegrenzungsventil 17/2 bzw. 36/2. Als zündwilliger Voreinspritzkraftstoff kann beispielsweise Dieselkraftstoff und als zündträger Haupteinspritzkraftstoff eine Diesel-Wasser-Emulsion oder Äthanol verwendet werden. Für den Fall, daß als zündwilliger Kraftstoff Dieselkraftstoff verwendet wird, können von der diesbezüglichen Niederdruck-Speiseeinrichtung 36 her auch die Pumpenräume 7 der Einspritzpumpe mit entsprechendem Kraftstoff versorgt werden.Each of the two fuels is provided in its own storage tank 41, 42 and is made from it by the associated low-pressure feed device 17 or 36 eligible. Each of the latter consists of a feed pump 17/1 or 36/1 and a pressure relief valve 17/2 or 36/2, which limits their delivery pressure to approximately 2 to 4 bar. For example, diesel fuel can be used as the ignitable pilot injection fuel and a diesel water emulsion or ethanol can be used as the ignition carrier main injection fuel. In the event that diesel fuel is used as the ignitable fuel, the pump chambers 7 of the injection pump can also be supplied with the appropriate fuel from the corresponding low-pressure feed device 36.

Nachfolgend ist die Funktion der erfindungsgemäßen Kraftstoffeinspritzung anhand eines vollständigen Kraftstoffschichtungsvorganges und anschließenden Einspritzvorganges geschildert.The function of the fuel injection according to the invention is described below on the basis of a complete fuel stratification process and subsequent injection process.

Nach Beendigung einer Einspritzung erfolgt zunächst eine Wiederauffüllung der im Einspritzsystem gegebenen Hohlräume. Dabei werden die beiden Kraftstoffe grundsätzlich so geschichtet, daß in der Nähe der Düsenbohrungen 32 im Düsenvorraum 26 Voreinspritzkraftstoff vorliegt und dahinter, also in größerer Entfernung der Haupteinspritzkraftstoff geschichtet wird. Nach Beendigung einer Einspritzung sind die sich an das Druckventil 14 anschließenden Leitungswege 8, 11 und alle ventilinternen Kanäle drucklos. Dieser Zustand ist dann gegeben, wenn der Druck in Pumpenraum 7 am Ende des Pumpenkolbenhubes zusammenbricht und infolge davon die Ventilnadel 20 schließt und das Druckventil 14 in seine Schließposition zurückkehrt. Anschließend wird zunächst das Magnetventil 38 von der Steuereinrichtung 40 her geöffnet, so daß durch die Niederdruck-Speiseeinrichtung 36 Voreinspritzkraftstoff in das Einspritzventil einleitbar ist, und zwar über den Zuführkanal 23 mit seinen Teilen 23/1, 23/2, 23/3, 23/4, 23/5, 23/6, wodurch der sich im Hohlraum 21 der Ventilnadel 20 befindliche Kraftstoff über die Drosselbohrungen 25 - unter Verdrängung des noch im Düsenvorraum 26 befindlichen Haupteinspritzkraftstoffes zurück in den Zuführkanal 10 - in den Düsenvorraum 26 ausgebracht wird. Sobald die entsprechende Menge an Voreinspritzkraftstoff im Düsenvorraum 26 vorgelagert ist, wird das Magnetventil 38 von der Steuereinrichtung 40 her wieder geschlossen und damit die Voreinspritzkraftstoff-Vorlagerung beendet. Anschließend oder mit geringer zeitlicher Voreilung vor dem Schließen des Magentventiles 38 wird das Magnetventil 19 geöffnet, so daß dann von der Niederdruck-Speiseeinrichtung 17 her Haupteinspritzkraftstoff über die Zuleitung 18 und die Füllbohrung 16 zur Auffüllung des in den Leitungswegen 8, 11 und 10 gegebenen Hohlraumes förderbar ist. Hierdurch wird der Haupteinspritzkraftstoff im ventilinternen Zuführkanal 10 dem bereits vorgelagerten Voreinspritzkraftstoff an diesen anschließend nachgelagert. Sobald dieser Nachfüllvorgang beendet ist, wird das Magnetventil 18 von der Steuereinrichtung 40 her wieder geschlossen. Die Öffnungszeit für das Magnetventil 18 ist so groß bemessen, daß immer alle Hohlräume aufgefüllt werden können. Der beschriebene Ablauf führt auch dann zu einer exakten Dosierung, wenn die eingestellte Menge kleiner war als die gewünschte Voreinspritzkraftstoffmenge. Die besagten Nachfüllvorgänge laufen praktisch während des Abwärtshubes des zugehörigen Pumpenkolbens 2 ab. Bei dem anschließenden, für die Einspritzung maßgeblichen Pumpenkolben-Aufwärtshub verdrängt der Pumpenkolben 2 nach Verschluß der Steuerbohrung 6 das Arbeitsmedium aus dem Pumpenraum 7. Dadurch wird das als Druckkolben wirkende Druckventil 14 gegen den Widerstand der Druckfeder 15 angehoben, wobei die Füllbohrung 16 verschlossen wird. In der Folge wird über die im Pumpenausgangsraum 8, der anschließenden Einspritzleitung 11 und dem ventilinternen Zuführkanal 10 anstehende Haupteinspritzkraftstoffsäule eine Druckwelle erzeugt, durch die die Ventilnadel 20 angehoben wird und eine Einspritzung erfolgt, wobei zunächst der Voreinspritzkraftstoff und anschließend der Haupteinspritzkraftstoff über die Düsenbohrungen 32 in den Brennraum der Brennkraftmaschine eingespritztwerden. Sobald vom Pumpenkolben 2 die Steuerbohrung 6 aufgesteuert wird, bricht die über die Kraftstoffsäule übertragene Druckwelle zusammen. In der Folge schließen die Ventilnadel 20 und das Druckventil 14, wodurch sich in den dahinter gegebenen Leitungswegen 8, 11,10 wieder ein Hohlraum in der Größe der eingespritzten Kraftstoffmenge ergibt. Beim folgenden Abwärtsgang des Pumpenkolbens 2 erfolgt dann wieder eine erneute Auffüllung des Einspritzsystems mit Voreinspritzkraftstoff und Haupteinspritzkraftstoff in der wie vorstehend angegebenen Weise.After the end of an injection, the cavities given in the injection system are first refilled. The two fuels are basically stratified in such a way that pre-injection fuel is present in the vicinity of the nozzle bores 32 in the nozzle vestibule 26 and the main injection fuel is stratified behind it, that is to say at a greater distance. After an injection has ended, the line paths 8, 11 adjoining the pressure valve 14 and all the channels inside the valve are depressurized. This state occurs when the pressure in the pump chamber 7 collapses at the end of the pump piston stroke and, as a result, the valve needle 20 closes and the pressure valve 14 returns to its closed position. Subsequently, the solenoid valve 38 is first opened from the control device 40, so that pre-injection fuel can be introduced into the injection valve 36 through the low-pressure feed device 36, specifically via the feed channel 23 with its parts 23/1, 23/2, 23/3, 23 / 4, 23/5, 23/6, as a result of which the fuel located in the cavity 21 of the valve needle 20 is discharged into the nozzle antechamber 26 via the throttle bores 25 - while displacing the main injection fuel still located in the nozzle antechamber 26 back into the supply channel 10. As soon as the corresponding amount of pre-injection fuel is stored upstream in the nozzle antechamber 26, the solenoid valve 38 is closed again by the control device 40 and the pre-injection fuel pre-storage is thus ended. Subsequently or with a slight advance in time before the closing of the magnetic valve 38, the solenoid valve 19 is opened, so that then main injection fuel from the low-pressure feed device 17 via the feed line 18 and the filling bore 16 for filling of the cavity given in the conduction paths 8, 11 and 10 can be conveyed. As a result, the main injection fuel in the valve-internal supply channel 10 is subsequently added to the pre-injection fuel which is already upstream of the latter. As soon as this refilling process has ended, the solenoid valve 18 is closed again by the control device 40. The opening time for the solenoid valve 18 is so large that all cavities can always be filled. The sequence described also leads to an exact metering if the set amount was smaller than the desired pre-injection fuel amount. Said refilling processes take place practically during the downward stroke of the associated pump piston 2. In the subsequent pump piston upward stroke, which is decisive for the injection, the pump piston 2 displaces the working medium from the pump chamber 7 after the control bore 6 has been closed. As a result, the pressure valve 14 acting as a pressure piston is raised against the resistance of the compression spring 15, the filling bore 16 being closed. As a result, a pressure wave is generated via the main injection fuel column in the pump outlet space 8, the subsequent injection line 11 and the valve-internal feed channel 10, by means of which the valve needle 20 is raised and an injection takes place, with the pre-injection fuel first and then the main injection fuel via the nozzle bores 32 in the combustion chamber of the internal combustion engine are injected. As soon as the control bore 6 is opened by the pump piston 2, the pressure wave transmitted via the fuel column breaks down. As a result, the valve needle 20 and the pressure valve 14 close, which again results in a cavity in the size of the injected fuel quantity in the line paths 8, 11, 10 behind it. In the subsequent downward gear of the pump piston 2, the injection system is again refilled with pre-injection fuel and main injection fuel in the manner indicated above.

Claims (8)

  1. A fuel injection device for pilot and main injection of various fuels via a single-needle injection valve (9), in which device pilot injection fuel from low pressure feed means (36) is conveyed into the injection valve, is then fed through the spring chamber (23/2) containing the compression spring (30) acting upon the valve needle (20) in the closing direction, and via a channel (23; 23/4, 23/5, 23/6) into a cavity (21) in the valve needle, and, from there via throttle bores (25) adjacent the seat of the valve needle, is stored prior to use in the nozzle antechamber (26), and subsequently main injection fuel is conveyed from an injection pump (1) via an injection pipe (11), or directly, and via a channel (10) inside the valve also into the nozzle antechamber behind the pilot injection fuel stored prior to use, wherein the valve needle (20) is bored to form the cavity from its rear end coaxially up to the vicinity of its tip, the rear of this cavity (21) is closed by a partially extending spacer bolt (28) connected to the pressure plate (29) of the compression spring (30) and is fillable with pilot injection fuel via the filling bore (22) behind an annular stroke surface (33) of the valve needle in the rear half thereof, wherein a non-return valve (24) allowing flow only in the feed direction is fitted in the supply channel (23; 23/4, 23/5, 23/6) characterised in that
    - the filling bore (22) is formed as a transverse bore extending from an annular groove (34) present on the outside of the valve needle (20) and connecting in every valve needle position to the supply channel (23),
    - the non-return valve (24) is fitted in an offset manner in the supply channel (23) inside the valve as close as possible before the joining of the said supply channel to the guide bore (35) for the valve needle (20),
    - the main injection fuel supply channel (10) inside the valve is formed only by interconnecting bore sections without attachments,
    - a correspondingly controllable solenoid valve (38) is fitted for exact metering, with respect to time and quantity, ofthe pilot injection fuel in an external feed pipe (37),
    - a pump exit chamber (8) containing a delivery valve (14) and a compression spring (15), is attached to each pump chamber (7) of the injection pump (1), and the supply channel (10) inside the injection valve is attached to the said pump exit chamber either via an injection pipe (11) or directly,
    - the injection pump (1) is only used to produce pressure and to advance the fuel pillar situated downstream of the delivery valve (14) in the adjacent pipe passages (8, 11, 10), wherein each delivery valve (14) acts as a pressure piston during the pump piston stroke, and also blocks a filling bore (16) leading to the side of the pump exit chamber (8), and when injection is over and the delivery valve (14) has been returned to the closed position the resulting cavity, corresponding to the injected quantity of fuel, in the said pipe passages (8, 11, 10) is refillable with main injection fuel by low pressure feed means (17) via the said filling bore, and is controlled shortly before or after the end of the pilot injection fuel refilling via a solenoid valve (19) fitted into a feed pipe (18).
  2. A fuel injection device according to Claim 1, characterised in that the supply channel (23) includes the spring chamber (23/2) containing the compression spring (30), an annular gap (23/3) around the pressure plate (29) and the spacer bolt (28), and continues with a transverse channel (23/4), a vertical bore (23/5) with the non-return valve (24) fitted therein, and an oblique bore (23/6) leading laterally to the receiving bore (35), guiding the valve needle (20), at the level of the filling bore (22).
  3. A fuel injection device according to Claim 1, characterised in that the two solenoid valves (19, 38) are controllable from electronic control means (40) operating on the basis of rotation angle signals (ϕ), supplied thereto, of the crankshaft or of a camshaft controlling the charge cycle valves or the pump pistons (2) ofthe injection pump (1), and with the opening and closing moments of the two solenoid valves (19, 38) being stored as rotation angle-dependent values therein.
  4. A fuel injection device according to Claim 3, characterised in that the two solenoid valves (19, 38) are included in a joint valve block (39), and the two supply pipes (18, 37) extend across the said valve block.
  5. A fuel injection device according to Claim 1, characterised in that each of the two fuels is provided in its own storage tank (41, 42) and is deliverable therefrom through the associated low pressure feed means (17, 36).
  6. A fuel injection device according to Claim 1, characterised in that each of the two low pressure feed means (17, 36) comprises a delivery pump (17/1, 36/1) and a pressure restricting valve (17/2, 36/2) restricting the supply pressure to approximately 2 to 4 bar.
  7. A fuel injection device according to Claim 1, characterised in that the pump chambers (7) of the injection pump (1) are also suppliable with the appropriate fuel by the low pressure feed means (36) delivering the ignitable fuel.
  8. A fuel injection device according to Claim 1, characterised by the use thereof for pilot injection of diesel fuel and for main injection of a diesel water emulsion or ethanol.
EP19930120307 1993-02-09 1993-12-16 Fuel injection de vice with pilot- and main-injection of different fuels through a one-needle injection valve Expired - Lifetime EP0610584B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT22393 1993-02-09
AT223/93 1993-02-09

Publications (2)

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EP0610584A1 EP0610584A1 (en) 1994-08-17
EP0610584B1 true EP0610584B1 (en) 1996-09-04

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EP19930120307 Expired - Lifetime EP0610584B1 (en) 1993-02-09 1993-12-16 Fuel injection de vice with pilot- and main-injection of different fuels through a one-needle injection valve

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EP (1) EP0610584B1 (en)
DE (1) DE59303657D1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101137614B1 (en) 2010-10-28 2012-04-19 현대중공업 주식회사 Fuel injection valve of internal combustion engines

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4422552C1 (en) * 1994-06-28 1995-11-30 Daimler Benz Ag Method for injecting fuel into the combustion chamber of an internal combustion engine
DE19706661A1 (en) * 1997-02-20 1998-08-27 Bosch Gmbh Robert Fuel injection valve for internal combustion engines
US8944027B2 (en) 2011-06-21 2015-02-03 Caterpillar Inc. Dual fuel injection compression ignition engine and method of operating same
US8733326B2 (en) 2011-06-24 2014-05-27 Caterpillar Inc. Dual fuel injector for a common rail system

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Publication number Priority date Publication date Assignee Title
DE3012418A1 (en) * 1980-03-29 1981-10-08 Klöckner-Humboldt-Deutz AG, 5000 Köln Fuel injection nozzle for IC engine - has second fuel passage for pilot fuel injection
GB2126650B (en) * 1982-08-31 1988-02-10 George Stan Baranescu I c engine injection system providing a stratified charge of two fuels
JP2538908B2 (en) * 1987-03-15 1996-10-02 三菱重工業株式会社 Two-fuel engine injection system
DE3928611A1 (en) * 1989-08-30 1991-03-07 Bosch Gmbh Robert INJECTION NOZZLE FOR DIESEL ENGINES
US5056469A (en) * 1990-06-29 1991-10-15 Ail Corporation Fuel injection system

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101137614B1 (en) 2010-10-28 2012-04-19 현대중공업 주식회사 Fuel injection valve of internal combustion engines
WO2012057530A3 (en) * 2010-10-28 2012-06-21 현대중공업 주식회사 Fuel-injection valve for an internal combustion engine
CN103180600A (en) * 2010-10-28 2013-06-26 现代重工业株式会社 Fuel-injection valve for an internal combustion engine
CN103180600B (en) * 2010-10-28 2015-07-15 现代重工业株式会社 Fuel-injection valve for an internal combustion engine
US9388782B2 (en) 2010-10-28 2016-07-12 Hyundai Heavy Industries, Co., Ltd. Fuel-injection valve for an internal combustion engine

Also Published As

Publication number Publication date
EP0610584A1 (en) 1994-08-17
DE59303657D1 (en) 1996-10-10

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