EP0372562B1 - Fuel injection device - Google Patents

Fuel injection device Download PDF

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Publication number
EP0372562B1
EP0372562B1 EP89122631A EP89122631A EP0372562B1 EP 0372562 B1 EP0372562 B1 EP 0372562B1 EP 89122631 A EP89122631 A EP 89122631A EP 89122631 A EP89122631 A EP 89122631A EP 0372562 B1 EP0372562 B1 EP 0372562B1
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EP
European Patent Office
Prior art keywords
control valve
bore
pressure
fuel injection
injection device
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 - Lifetime
Application number
EP89122631A
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German (de)
French (fr)
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EP0372562A1 (en
Inventor
Reda Rizk
Hans-Gottfried Michels
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Kloeckner Humboldt Deutz AG
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Kloeckner Humboldt Deutz AG
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Priority to AT89122631T priority Critical patent/ATE82043T1/en
Publication of EP0372562A1 publication Critical patent/EP0372562A1/en
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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
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/20—Varying fuel delivery in quantity or timing
    • F02M59/36—Varying fuel delivery in quantity or timing by variably-timed valves controlling fuel passages to pumping elements or overflow passages
    • F02M59/366—Valves being actuated electrically
    • 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
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
    • F02M59/46—Valves
    • F02M59/466—Electrically operated valves, e.g. using electromagnetic or piezoelectric operating means
    • 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
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
    • F02M59/48—Assembling; Disassembling; Replacing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B3/00—Engines characterised by air compression and subsequent fuel addition
    • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition
    • 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
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/30—Fuel-injection apparatus having mechanical parts, the movement of which is damped
    • F02M2200/304—Fuel-injection apparatus having mechanical parts, the movement of which is damped using hydraulic means

Definitions

  • the invention relates to a fuel injection device according to the preamble of claim 1.
  • This control valve body tends to bounce due to its relatively high dimensions and insufficient damping. This affects the accuracy of the start of delivery and causes a quantity spread between the individual pump elements.
  • the object of the invention is to avoid this disadvantage and to create a functionally reliable control valve.
  • the arrangement according to the invention of the ventilation or fuel return line has the effect that air-free fuel with a largely constant temperature is located in the damping chamber due to its fuel flow. In this way, constant damping is achieved. In addition, the cooling of the electromagnetic actuator and the dissipation of the damping heat is achieved.
  • An advantageous embodiment of the invention has the effect that the form required for the damping prevails in the damping space.
  • the level of this admission pressure allows the desired flow through the damping space, since there is a positive pressure drop between the low pressure spaces and the damping space.
  • a rebound-free closing of the control valve is achieved by coordinating all of the damping-relevant parameters and thus enables precise control of the start of delivery and the delivery rate of the fuel.
  • the design of the anchor plate as a solid disc without openings is of particular importance for effective damping.
  • the inventive design of the outer contour of the injection pump element makes it possible to replace a normal element with the injection pump element with a control valve without any reworking.
  • the position of the high-pressure chamber and the suction or discharge borehole according to the invention enables a minimal harmful space in the high-pressure region, which is comparable to the harmful space of a normal element.
  • control valve For an unrestricted and uncomplicated interchangeability of the control valve, it is important to provide a certain play between the stepped bore in the injection pump element and the control valve.
  • This installation clearance is advantageously bridged by two sealing elements which, in addition to their function as a high-pressure seal, take over the bearing of the control valve in the stepped bore of the plunger bush.
  • the fuel which is controlled by the control valve body is returned to the low-pressure chamber through a bore in the plunger sleeve. This avoids expensive external connection lines with their risk of leakage.
  • the fuel injection device consists of an injection pump element 1 and a control valve 2, the injection pump element 1 also being the carrier of the control valve 2.
  • the injection pump element is composed of a pump plunger 4, a plunger sleeve 5 and a commercially available relief valve 6,
  • the control valve 2 consists of a control valve element 3 and an electromagnetic actuating device 7.
  • the pump plunger 4 which is sealingly guided in the plunger sleeve 5, is moved in the direction of the pump plunger axis by a cam, not shown, via a roller tappet, also not shown.
  • the pump plunger 4 has a control groove 8, which is connected to a high-pressure chamber 11 via a longitudinal control bore 9 and a transverse control bore 10.
  • the high-pressure chamber 11 is located via a high-pressure bore 12 and the control valve element 3 with the relief valve 6 and further via an injection line, not shown, in connection with a fuel injector, also not shown.
  • the high-pressure chamber 11 is pulled up to just below a stepped bore 19, which is used to hold the control valve 2. This minimizes the harmful volume between the high-pressure chamber 11 and the relief valve 6, which proves to be particularly advantageous at high injection pressures.
  • the difference in the harmful volume due to the high-pressure bore 12 and the high-pressure control bore 28 compared to a normal element 1 a can be compensated for by adjusting the injection line length.
  • the high-pressure chamber 11 has no end cover, since the injection pump element 1 is designed as a so-called "mono element".
  • the design as a mono element advantageously increases the high-pressure capability of the fuel injection device by minimizing the expansion of the pressure space.
  • a suction or discharge bore 14 which connects the high-pressure chamber 11 to a low-pressure chamber 13, which in turn is connected to the suction chamber of the injection pump housing, not shown.
  • the suction or discharge bore 14 is drilled obliquely from the low-pressure chamber 13 in the direction of the high-pressure chamber 11 in order to take into account the changed position of the high-pressure chamber 11.
  • the low pressure chamber 13 is also via a return bore 15 with an annular space 16 of a control valve sleeve 17 of the control valve element 3 connected. This avoids an external return line, which means construction costs and risk of leakage.
  • the injection pump element 1 has a pump element flange 18, via which the injection pump element 1 is fastened to the pump housing, not shown.
  • the dimensions of the pump element flange 18 and the outer contour of the plunger sleeve 5 in the region of the pump housing correspond to the contour of a normal injection pump element 1a.
  • the pump plunger 4 is adapted to the changed position of the high-pressure chamber 11 by a corresponding change in its length, so that, as can be seen from FIG. 1, the position of a pressure mushroom 47 of both injection pump elements is the same when the pump plunger is in the bottom dead center. Since the width of both injection pump elements also matches, a mutual exchange is possible without rework. Therefore, both injection pump elements are suitable for block and single injection pumps.
  • the control valve element 3 sits with a clearance fit in the stepped bore 19 of the plunger sleeve 5 and is mounted in two high-pressure sealing elements 20. It is connected by screws, not shown, which are inserted through bores in an end cover 21 and the plunger sleeve 5 and screwed into the control valve sleeve 17 to form a firm bond with the plunger sleeve 5. Due to the installation clearance between the control valve sleeve 17 and the stepped bore 19, tensioning and consequently jamming of the control valve element 3, caused by tightening the fastening screws of the relief valve 6 or the injection line (not shown), is avoided.
  • a particular advantage of this arrangement is that an independent exchange of control valve 2 and injection pump element 1 as well as the actuating device 7 is ensured.
  • This modular structure enables cost-effective production and repair of the fuel injection device.
  • the control valve element 3 has a control valve sleeve 17 and a control valve body 22 which is guided so that it can move axially in the control valve sleeve 17, specifically in a high-pressure guide 23 and a low-pressure guide 24.
  • the control valve body 22 uses a control valve seat 25 to separate a high-pressure annular space 26 from a low-pressure annular space 27.
  • the high-pressure annular space 26 is connected to the high-pressure space 11 and the relief valve 6 via a high-pressure control bore 28 and the high-pressure bore 12.
  • the low-pressure annular space 27 is connected to the low-pressure space 13 via the control bore 29, the annular space 16 and the return bore 15.
  • the control valve body 22 has a leak oil longitudinal bore 42 and a leak oil transverse bore 43, which create a connection between a leak oil chamber 44 and a spring chamber 34.
  • an anchor plate 30 is fastened, which is moved by the electromagnetic actuating device 7.
  • the anchor plate 30 is fastened by means of a countersunk screw 31 screwed into the control valve body 22, which axially clamps the anchor plate 30 and a stop ring 32 against the control valve body 22.
  • the anchor plate 30 is located in a fuel-filled damping space 33, which is delimited by an intermediate piece 41 and the electromagnetic actuating device 7.
  • the volume of the damping space 33 is dimensioned such that during the axial movement of the anchor plate 30 there are no appreciable flow resistances between the anchor plate 30 and the walls of the intermediate piece 41.
  • the damping chamber 33 is connected to a spring chamber 34, which is also fuel-filled.
  • a spring 36 In the spring chamber 34 there is a spring 36, the force of which acts on the stop ring 32 in the direction of the stop 35.
  • the stop 35 serves to limit the stroke of the control valve body 22.
  • the damping chamber 33 and the spring chamber 34 are connected to the control bore 29 via a throttle bore 37.
  • a threaded bore 38 is provided, to which a ventilation or fuel return line 39 is connected, which leads to the fuel tank (not shown).
  • a pressure holding valve 40 is arranged, the cut-off pressure of which is lower than the delivery pressure of the fuel delivery pump, not shown.
  • the electromagnetic adjusting device 7 is clamped against the control valve sleeve 17 by screws (not shown), acting parallel to the axis of the control valve body 22, with the intermediate piece 41, without bracing the latter.
  • the entire low-pressure area of the control valve 2 is sealed by O-rings 45.
  • the fuel injector works as follows: During the delivery stroke, the pump plunger 4 is moved from its bottom dead center position in the direction of the control valve unit 2. After passing through a preliminary stroke, it first closes the suction and discharge bore 14. The plunger 4 then delivers fuel into the high-pressure bore 12 and into the high-pressure control bore 28.
  • the spring 36 When the anchor plate 30 is tightened, the spring 36 is also preloaded. As soon as the electromagnetic actuating device 7 is de-energized, the spring 36 lifts the control valve body 22 from its seat 25. As a result, the fuel flows back into the low-pressure chambers and the fuel injection is ended.
  • a prerequisite for the precise function of the control valve 2 and thus for reproducible delivery start and fluctuation-free delivery quantity is a rebound-free placement of the control valve body 22 on the control valve seat 25.
  • This is achieved according to the invention by a fine-tuned damping of the movement of the control valve body 22.
  • the displacement flow is between Anchor plate 30 and the electromagnetic actuator 7 used.
  • the armature plate 30 is designed without open, axial bores in order to effect the most effective squeezing flow at the stroke end between the armature plate 30 and the electromagnetic actuating device 7.
  • the amount of damping required depends, among other things, on the moving mass, i. H. from the mass of the control valve body 22 + anchor plate 30 + countersunk screw 31 + stop ring 32 + proportion of the mass of the spring 36. Another factor relevant for damping is the spring stiffness of the control valve seat 25.
  • the damping itself depends, among other things, on the fuel viscosity, the geometry of the anchor plate 30 and the minimum distance 46 between the anchor plate 30 and the electromagnetic actuating device 7 and on the pressure in the damping chamber. These influencing factors have to be coordinated. The optimal adjustment is achieved when the control valve body 22 is placed on the control valve seat 25 without kickback and the damping-related slowdown in the movement of the control valve body 22 is minimized.
  • the supply of the damping chamber 33 with damping liquid, for. B. damping oil can be done via a separate damping oil circuit.
  • damping space 33 For proper functioning of the damping, it is important that there is no air in the damping space 33, since this affects the viscosity and compressibility of the damping medium. It is also important that the damping fluid is renewed continuously as it warms up and ages.
  • the venting of the damping chamber 33 is accomplished via the threaded bore 38, which is provided in such a way that it is located in the installed position of the control valve 2 in the region of the highest point of the damping chamber 33.
  • the vent or fuel return line 39 is connected to the threaded bore 38, through which the fuel flows back via the pressure holding valve 40 to the fuel tank, not shown.
  • the pressure holding valve 40 ensures a certain liquid pressure in the damping chamber 33, which is lower than the maximum delivery pressure of the low-pressure pump, not shown, and lower than the pressure in the low-pressure chambers of the fuel injector. This ensures a flow through the damping chamber 33 and thus renewal of the damping medium fuel and cooling of the control valve 2.
  • the pressure-maintaining valve 40 has the effect that the damping chamber 33 cannot run empty when the engine is at a standstill, which leads to undamped lifting movement and thus to bouncing of the control valve 3.
  • the leak oil from the leak oil chamber 44 is guided via the leak oil longitudinal bore 42 and the leak oil cross bore 43 in the control valve body 22 to the spring chamber 34 and thus into the damping oil circuit.
  • This solution according to the invention saves a separate leakage oil return line.
  • control groove 8 of the pump plunger 4 at the end of the delivery stroke ensures control of the fuel in the suction or control bore 14.
  • the fuel injection is ended in any case before the delivery into the top area of the injection pump cam arrives and overloaded it.
  • the pump plunger 4 of the injection pump element 1 is considerably easier to manufacture; than that of the normal element 1a, since the twisting device and the precise control edges are eliminated.
  • the fuel injection device according to the invention allows a precise determination of the start of delivery and metering of the fuel injection quantity by the rebound-free placement of the control valve body 22 on the control valve seat 25.
  • it is easy to manufacture and service, since the main components of the injection pump element 1, control valve 2 and electromagnetic actuating device 7 are independent of one another manufacture, check and replace.

Abstract

The invention has the object of improving a known fuel injection device, which comprises an injection pump element with an electromagnetically actuated control valve body, mounted in the latter, for controlling the beginning of delivery and the delivery quantity, in such a way that the injection pump element and the control valve are individually exchangeable and that the control valve body moves onto its seat without rebound. <??>The solution comprises a control valve (2) which is arranged with clearance in a stepped hole (19) of a plunger sleeve (5) and is mounted in sealing elements (20). The freedom from rebound is achieved by matching a minimum spacing (46) between an armature plate (30) and an electromagnetic regulating device (7), the armature plate (30) being situated in a fluid-filled damping space (33) and the minimum spacing (46) being optimised as a function of the mass of the moving parts of the control valve (2), the spring stiffness of a control valve seat (25), the geometry of an armature plate (30) and the viscosity of the fuel in the operating temperature range. <??>The invention is suitable for diesel engines. <IMAGE>

Description

Die Erfindung betrifft eine Brennstoffeinspritzvorrichtung nach dem Oberbegriff des Anspruchs 1.The invention relates to a fuel injection device according to the preamble of claim 1.

In der gattungsbildenden DE-OS 35 36 828 wird eine Brennstoffeinspritzvorrichtung mit einem Steuerventil beschrieben, deren Steuerventilkörper durch eine elektromagnetische Stellvorrichtung betätigbar ist.In the generic DE-OS 35 36 828 a fuel injection device is described with a control valve, the control valve body is actuated by an electromagnetic actuator.

Dieser Steuerventilkörper neigt aufgrund seiner relativ hohen Maße und einer zu geringen Dämpfung zum Sitzprellen. Dadurch wird die Genauigkeit des Förderbeginns beeinträchtigt und eine Mengenstreuung zwischen den einzelnen Pumpenlementen verursacht.This control valve body tends to bounce due to its relatively high dimensions and insufficient damping. This affects the accuracy of the start of delivery and causes a quantity spread between the individual pump elements.

Der Erfindung liegt die Aufgabe zugrunde, diesen Nachteil zu vermeiden und ein funktionssicheres Steuerventil zu schaffen.The object of the invention is to avoid this disadvantage and to create a functionally reliable control valve.

Diese Aufgabe wird erfindungsgemäß durch die kennzeichnenden Merkmale des Anspruchs 1 gelöst. Durch die erfindungsgemäße Ausbildung und Anordnung der Ankerplatte und der elektromagnetischen Stellvorrichtung entsteht zwischen beiden eine Verdrängerströmung, deren Intensivität und Dämpfungskraft unter anderem mit abnehmendem Abstand beider ansteigt. Dadurch wird eine wichtige Voraussetzung zur Vermeidung des Sitzprellens des Steuerventilkörpers erfüllt.This object is achieved by the characterizing features of claim 1. The inventive design and arrangement of the anchor plate and the electromagnetic actuating device creates a displacement flow between the two, the intensity and damping force of which increases, inter alia, with a decreasing distance between the two. This becomes an important prerequisite for Avoidance of seat bounce of the control valve body fulfilled.

Durch eine vorteilhafte Weiterentwicklung der Erfindung wird ein besonders einfacher Aufbau des Steuerventils erreicht, da als Dämpfungsflüssigkeit Brennstoff verwendet wird, wodurch sich eine spezielle Dämpfungsflüssigkeit mit separatem Kreislauf erübrigt. Die erfindungsgemäße Drosselbohrung zwischen dem Dämpfungsraum und den niederdruckführenden Räumen verhindert, daß Druckstöße aus dem Niederdruckbereich in den Dämpfungsraum gelangen und dort die Dämpfungsverhältnisse ungewollt beeinflussen.An advantageous further development of the invention achieves a particularly simple construction of the control valve, since fuel is used as the damping liquid, which makes a special damping liquid with a separate circuit unnecessary. The throttle bore according to the invention between the damping space and the low-pressure spaces prevents pressure surges from the low-pressure region from reaching the damping space and undesirably influencing the damping conditions there.

Die erfindungsgemäße Anordnung der Entlüftungs- bzw. Brennstoffrücklaufleitung bewirkt, daß sich im Dämpfungsraum aufgrund von dessen Brennstoffdurchströmung luft-freier Brennstoff mit weitgehend konstanter Temperatur befindet. Auf diese Weise wird eine konstante Dämpfung erzielt. Außerdem wird die Kühlung des elektromagnetischen Stellgliedes und die Abfuhr der Dämpfungswärme erreicht.The arrangement according to the invention of the ventilation or fuel return line has the effect that air-free fuel with a largely constant temperature is located in the damping chamber due to its fuel flow. In this way, constant damping is achieved. In addition, the cooling of the electromagnetic actuator and the dissipation of the damping heat is achieved.

Eine vorteilhafte Ausbildung der Erfindung bewirkt, daß im Dämpfungsraum der für die Dämpfung erforderliche Vordruck herrscht. Die Höhe dieses Vordrucks gestattet die gewünschte Durchströmung des Dämpfungsraumes, da ein positives Druckgefälle zwischen den Niederdruckräumen und dem Dämpfungsraum vorliegt.An advantageous embodiment of the invention has the effect that the form required for the damping prevails in the damping space. The level of this admission pressure allows the desired flow through the damping space, since there is a positive pressure drop between the low pressure spaces and the damping space.

Erfindungsgemäß wird durch Abstimmung aller dämpfungsrelevanter Parameter ein rückprallfreies Schließen des Steuerventils erreicht und damit ein exaktes Steuern von Förderbeginn und Fördermenge des Brennstoffs ermöglicht. Dabei ist die Ausbildung der Ankerplatte als massive Scheibe ohne Durchbrechungen für eine wirksame Dämpfung von besonderer Bedeutung.According to the invention, a rebound-free closing of the control valve is achieved by coordinating all of the damping-relevant parameters and thus enables precise control of the start of delivery and the delivery rate of the fuel. The design of the anchor plate as a solid disc without openings is of particular importance for effective damping.

Eine vorteilhafte Weiterbildung der Erfindung mit einer Lecköllängs- und Querbohrung des Steuerventilkörpers erübrigt eine gesonderte Leckölrückführleitung und den damit verbundenen Aufwand und die Leckagegefahr.An advantageous development of the invention with a leak oil longitudinal and transverse bore of the control valve body eliminates the need for a separate leak oil return line and the associated effort and the risk of leakage.

Durch die erfindungsgemäße Ausbildung der äußeren Kontur des Einspritzpumpenelementes ist ein Austausch eines Normalelementes gegen das Einspritzpumpenelement mit Steuerventil ohne jede Nacharbeit möglich.The inventive design of the outer contour of the injection pump element makes it possible to replace a normal element with the injection pump element with a control valve without any reworking.

Die erfindungsgemäße Lage von Hochdruckraum und Saug- bzw. Absteuerbohrung ermöglicht einen minimalen schädlichen Raum im Hochdruckbereich, der mit dem schädlichen Raum eines Normalelementes vergleichbar ist.The position of the high-pressure chamber and the suction or discharge borehole according to the invention enables a minimal harmful space in the high-pressure region, which is comparable to the harmful space of a normal element.

Für eine uneingeschränkte und unkomplizierte Austauschbarkeit des Steuerventils ist es wichtig, ein gewisses Spiel zwischen der Stufenbohrung im Einspritzpumpenelement und dem Steuerventil vorzusehen.For an unrestricted and uncomplicated interchangeability of the control valve, it is important to provide a certain play between the stepped bore in the injection pump element and the control valve.

In vorteilhafter Weise wird dieses Einbauspiel durch zwei Dichtelemente überbrückt, die neben ihrer Funktion als Hochdruckdichtung gleichsam eine Lagerung des Steuerventils in der Stufenbohrung der Plungerbüchse übernehmen.This installation clearance is advantageously bridged by two sealing elements which, in addition to their function as a high-pressure seal, take over the bearing of the control valve in the stepped bore of the plunger bush.

Durch eine vorteilhafte Weiterbildung der Erfindung wird der Brennstoff, der vom Steuerventilkörper abgesteuert wird, durch eine Bohrung in der Plungerbüchse zum Niederdruckraum zurückgeführt. Damit werden aufwendige äußere Verbindungsleitungen mit ihrer Leckagegefahr vermieden.In an advantageous development of the invention, the fuel which is controlled by the control valve body is returned to the low-pressure chamber through a bore in the plunger sleeve. This avoids expensive external connection lines with their risk of leakage.

durch eine vorteilhafte Ausbildung des Pumpenplungers mit einer Absteuernut wird erreicht, daß unabhängig von der Betriebstüchtigkeit des Steuerventils die Förderung der Einspritzpumpe unterbrochen wird, bevor die Förderung in den Kuppenradius des Einspritzpumpennockens läuft.by an advantageous design of the pump plunger with a Absteuernut ensures that regardless of the efficiency of the control valve, the promotion of Injection pump is interrupted before the delivery runs into the tip radius of the injection pump cam.

Weitere Merkmale der Erfindung ergeben sich aus der folgenden Beschreibung und der Zeichnung, in der Ausführungsbeispiele der Erfindung schematisch dargestellt sind.Further features of the invention result from the following description and the drawing, in which exemplary embodiments of the invention are shown schematically.

Es zeigen:

  • Fig. 1: einen Querschnitt durch die Brennstoffeinspritzvorrichtung und durch ein Normalelement,
  • Fig. 2: Detailschnitt durch die Brennstoffeinspritzvorrichtung.
Show it:
  • 1 shows a cross section through the fuel injection device and through a normal element,
  • Fig. 2: Detail section through the fuel injection device.

Die Brennstoffeinspritzvorrichtung besteht aus einem Einspritzpumpenelement 1 und einem Steuerventil 2, wobei das Einspritzpumpenelement 1 zugleich Träger des Steuerventils 2 ist. Das Einspritzpumpenelement setzt sich zusammen aus einem Pumpenplunger 4, einer Plungerbüchse 5 und einem handelsüblichen Entlastungsventil 6, das Steuerventil 2 aus einem Steuerventilelement 3 und einer elektromagnetischen Stellvorrichtung 7.The fuel injection device consists of an injection pump element 1 and a control valve 2, the injection pump element 1 also being the carrier of the control valve 2. The injection pump element is composed of a pump plunger 4, a plunger sleeve 5 and a commercially available relief valve 6, the control valve 2 consists of a control valve element 3 and an electromagnetic actuating device 7.

Der Pumpenplunger 4, der in der Plungerbüchse 5 dichtend geführt ist, wird von einem nicht dargestellten Nocken über einen ebenfalls nicht dargestellten Rollenstößel in Richtung der Pumpenplungerachse bewegt. Der Pumpenplunger 4 besitzt eine Absteuernut 8, die über eine Absteuerlängsbohrung 9 und eine Absteuerquerbohrung 10 mit einem Hochdruckraum 11 in Verbindung steht.The pump plunger 4, which is sealingly guided in the plunger sleeve 5, is moved in the direction of the pump plunger axis by a cam, not shown, via a roller tappet, also not shown. The pump plunger 4 has a control groove 8, which is connected to a high-pressure chamber 11 via a longitudinal control bore 9 and a transverse control bore 10.

Der Hochdruckraum 11 steht über eine Hochdruckbohrung 12 und das Steuerventilelement 3 mit dem Entlastungsventil 6 und weiter über eine nicht dargestellte Einspritzleitung mit einem ebenfalls nicht dargestellten Brennstoffeinspritzventil in Verbindung.The high-pressure chamber 11 is located via a high-pressure bore 12 and the control valve element 3 with the relief valve 6 and further via an injection line, not shown, in connection with a fuel injector, also not shown.

Der Hochdruckraum 11 ist bis kurz unterhalb einer Stufenbohrung 19, die zur Aufnahme des Steuerventils 2 dient, hochgezogen. Dadurch wird das schädliche Volumen zwischen Hochdruckraum 11 und Entlastungsventil 6 minimiert, was sich bei hohen Einspritzdrücken besonders vorteilhaft erweist. Die gegenüber einem Normalelement 1a verbleibende Differenz des schädlichen Volumens durch die Hochdruckbohrung 12 und die Hochdrucksteuerbohrung 28 kann durch Anpassen der Einspritzleitungslänge ausgeglichen werden.The high-pressure chamber 11 is pulled up to just below a stepped bore 19, which is used to hold the control valve 2. This minimizes the harmful volume between the high-pressure chamber 11 and the relief valve 6, which proves to be particularly advantageous at high injection pressures. The difference in the harmful volume due to the high-pressure bore 12 and the high-pressure control bore 28 compared to a normal element 1 a can be compensated for by adjusting the injection line length.

Der Hochdruckraum 11 besitzt keinen Abschlußdeckel, da das Einspritzpumpenelement 1 als sogenanntes "Monoelement" ausgebildet ist. Die Ausbildung als Monoelement steigert in vorteilhafter Weise die Hochdruckfähigkeit der Brennstoffeinspritzvorrichtung durch Minimierung der Druckraumausweitung.The high-pressure chamber 11 has no end cover, since the injection pump element 1 is designed as a so-called "mono element". The design as a mono element advantageously increases the high-pressure capability of the fuel injection device by minimizing the expansion of the pressure space.

In der Plungerbüchse 5 befindet sich eine Saug- bzw. Absteuerbohrung 14, die den Hochdruckraum 11 mit einem Niederdruckraum 13 verbindet, der wiederum mit dem nicht dargestellten Saugraum des Einspritzpumpengehäuses verbunden ist.In the plunger bushing 5 there is a suction or discharge bore 14 which connects the high-pressure chamber 11 to a low-pressure chamber 13, which in turn is connected to the suction chamber of the injection pump housing, not shown.

Die Saug- bzw. Absteuerbohrung 14 ist im Unterschied zum Normalelement 1a vom Niederdruckraum 13 aus schräg in Richtung Hochdruckraum 11 gebohrt, um der geänderten Lage des Hochdruckraumes 11 Rechnung zu tragen.In contrast to the normal element 1a, the suction or discharge bore 14 is drilled obliquely from the low-pressure chamber 13 in the direction of the high-pressure chamber 11 in order to take into account the changed position of the high-pressure chamber 11.

Der Niederdruckraum 13 ist außerdem über eine Rücklaufbohrung 15 mit einem Ringraum 16 einer Steuerventilbüchse 17 des Steuerventilelementes 3 verbunden. Dadurch wird eine externe Rücklaufleitung, die Bauaufwand und Leckage-risiko bedeutet, vermieden.The low pressure chamber 13 is also via a return bore 15 with an annular space 16 of a control valve sleeve 17 of the control valve element 3 connected. This avoids an external return line, which means construction costs and risk of leakage.

Das Einspritzpumpenelement 1 besitzt einen Pumpenelementflansch 18, über den das Einspritzpumpenelement 1 am nicht dargestellten Pumpengehäuse befestigt ist. Die Abmessungen des Pumpenelementenflansches 18 und die Außenkontur der Plungerbüchse 5 im Bereich des Pumpengehäuses entsprechen der Kontur eines Normaleinspritzpumpenelements 1a.The injection pump element 1 has a pump element flange 18, via which the injection pump element 1 is fastened to the pump housing, not shown. The dimensions of the pump element flange 18 and the outer contour of the plunger sleeve 5 in the region of the pump housing correspond to the contour of a normal injection pump element 1a.

Der Pumpenplunger 4 ist der veränderten Lage des Hochdruckraumes 11 durch entsprechende Änderung seiner Länge angepaßt, so daß, wie aus Fig. 1 ersichtlich, die Lage eines Druckpilzes 47 beider Einspritzpumpenelemente bei Stellung der Pumpenplunger im unteren Totpunkt gleich ist. Da außerdem die Baubreite beider Einspritzpumpenelemente übereinstimmt, ist ein wechselseitiger Austausch ohne Nacharbeit möglich. Deshalb sind beide Einspritzpumpenelemente für Block- und Einzeleinspritzpumpen geeignet.The pump plunger 4 is adapted to the changed position of the high-pressure chamber 11 by a corresponding change in its length, so that, as can be seen from FIG. 1, the position of a pressure mushroom 47 of both injection pump elements is the same when the pump plunger is in the bottom dead center. Since the width of both injection pump elements also matches, a mutual exchange is possible without rework. Therefore, both injection pump elements are suitable for block and single injection pumps.

Das Steuerventilelement 3 sitzt mit Spielpassung in der Stufenbohrung 19 der Plungerbüchse 5 und ist in zwei Hochdruckdichtelemente 20 gelagert. Es wird durch nicht dargestellte Schrauben, die durch Bohrungen in einem Abschlußdeckel 21 und der Plungerbüchse 5 hindurchgesteckt und in die Steuerventilbüchse 17 eingeschraubt werden, zu einem festen Verband mit der Plungerbüchse 5 verbunden. Durch das Einbauspiel zwischen Steuerventilbüchse 17 und Stufenbohrung 19 wird ein Verspannen und folglich ein Klemmen des Steuerventilelements 3, verursacht durch das Anziehen der Befestigungsschrauben des Entlastungsventils 6 oder der nicht dargestellten Einspritzleitung, vermieden.The control valve element 3 sits with a clearance fit in the stepped bore 19 of the plunger sleeve 5 and is mounted in two high-pressure sealing elements 20. It is connected by screws, not shown, which are inserted through bores in an end cover 21 and the plunger sleeve 5 and screwed into the control valve sleeve 17 to form a firm bond with the plunger sleeve 5. Due to the installation clearance between the control valve sleeve 17 and the stepped bore 19, tensioning and consequently jamming of the control valve element 3, caused by tightening the fastening screws of the relief valve 6 or the injection line (not shown), is avoided.

Ein besonderer Vorteil dieser Anordnung besteht darin, daß ein unabhängiger Austausch von Steuerventil 2 und Einspritzpumpenelement 1 so wie die Stellvorrichtung 7 sichergestellt ist. Durch diesen modularen Aufbau ist eine kostengünstige Fertigung und Reparatur der Brennstoffeinspritzvorrichtung möglich.A particular advantage of this arrangement is that an independent exchange of control valve 2 and injection pump element 1 as well as the actuating device 7 is ensured. This modular structure enables cost-effective production and repair of the fuel injection device.

Das Steuerventilelement 3 besitzt eine Steuerventilbüchse 17 und einen Steuerventilkörper 22, der in der Steuerventilbüchse 17 axial beweglich geführt ist, und zwar in einer Hochdruckführung 23 und einer Niederdruckführung 24.The control valve element 3 has a control valve sleeve 17 and a control valve body 22 which is guided so that it can move axially in the control valve sleeve 17, specifically in a high-pressure guide 23 and a low-pressure guide 24.

Der Steuerventilkörper 22 trennt mit einem Steuerventilsitz 25 einen Hochdruckringraum 26 von einem Niederdruckringraum 27. Der Hochdruckringraum 26 ist über eine Hochdrucksteuerbohrung 28 und die Hochdruckbohrung 12 mit dem Hochdruckraum 11 bzw. dem Entlastungsventil 6 verbunden. Der Niederdruckringraum 27 ist über die Absteuerbohrung 29, den Ringraum 16 und die Rücklaufbohrung 15 mit dem Niederdruckraum 13 verbunden.The control valve body 22 uses a control valve seat 25 to separate a high-pressure annular space 26 from a low-pressure annular space 27. The high-pressure annular space 26 is connected to the high-pressure space 11 and the relief valve 6 via a high-pressure control bore 28 and the high-pressure bore 12. The low-pressure annular space 27 is connected to the low-pressure space 13 via the control bore 29, the annular space 16 and the return bore 15.

Der Steuerventilkörper 22 besitzt eine Lecköllängsbohrung 42 und eine Leckölquerbohrung 43, die eine Verbindung zwischen einem Leckölraum 44 und einem Federraum 34 schaffen.The control valve body 22 has a leak oil longitudinal bore 42 and a leak oil transverse bore 43, which create a connection between a leak oil chamber 44 and a spring chamber 34.

An dem Ende des Steuerventilkörpers 22, an dem sich die Niederdruckführung 24 befindet, ist eine Ankerplatte 30 befestigt, die von der elektromagnetischen Stellvorrichtung 7 bewegt wird. Die Befestigung der Ankerplatte 30 geschieht mittels einer in den Steuerventilkörper 22 geschraubten Senkschraube 31, die die Ankerplatte 30 und einen Anschlagring 32 axial gegen den Steuerventilkörper 22 spannt.At the end of the control valve body 22, on which the low-pressure guide 24 is located, an anchor plate 30 is fastened, which is moved by the electromagnetic actuating device 7. The anchor plate 30 is fastened by means of a countersunk screw 31 screwed into the control valve body 22, which axially clamps the anchor plate 30 and a stop ring 32 against the control valve body 22.

Die Ankerplatte 30 befindet sich in einem kraftstoffgefüllten Dämpfungsraum 33, der von einem Zwischenstück 41 und der elektromagnetischen Stellvorrichtung 7 begrenzt wird. Das Volumen des Dämpfungsraumes 33 ist so dimensioniert, daß bei der axialen Bewegung der Ankerplatte 30 keine nennenswerten Strömungswiderstände zwischen der Ankerplatte 30 und den Wänden des Zwischenstückes 41 auftreten.The anchor plate 30 is located in a fuel-filled damping space 33, which is delimited by an intermediate piece 41 and the electromagnetic actuating device 7. The volume of the damping space 33 is dimensioned such that during the axial movement of the anchor plate 30 there are no appreciable flow resistances between the anchor plate 30 and the walls of the intermediate piece 41.

Der Dämpfungsraum 33 steht in Verbindung mit einem ebenfalls brennstoffgefüllten Federraum 34. Im Federrraum 34 befindet sich eine Feder 36, deren Kraft den Anschlagring 32 in Richtung Anschlag 35 beaufschlagt. Der Anschlag 35 dient als Hubbegrenzung des Steuerventilkörpers 22.The damping chamber 33 is connected to a spring chamber 34, which is also fuel-filled. In the spring chamber 34 there is a spring 36, the force of which acts on the stop ring 32 in the direction of the stop 35. The stop 35 serves to limit the stroke of the control valve body 22.

Der Dämpfungsraum 33 und der Federraum 34 stehen über eine Drosselbohrung 37 mit der Absteuerbohrung 29 in Verbindung.The damping chamber 33 and the spring chamber 34 are connected to the control bore 29 via a throttle bore 37.

Im Bereich der in Einbaulage höchsten Stelle des Dämpfungsraumes 33 ist eine Gewindebohrung 38 angebracht, an die eine Entlüftungs- bzw. Brennstoffrücklaufleitung 39 angeschlossen ist, die zum nicht abgebildeten Brennstofftank führt.In the area of the highest point of the damping space 33 in the installed position, a threaded bore 38 is provided, to which a ventilation or fuel return line 39 is connected, which leads to the fuel tank (not shown).

In dieser Entlüftungs- bzw. Brennstoffrücklaufleitung 39 ist eine Druckhalteventil 40 angeordnet, dessen Absteuerdruck kleiner als der Förderdruck der nicht abgebildeten Kraftstofförderpumpe ist.In this venting or fuel return line 39, a pressure holding valve 40 is arranged, the cut-off pressure of which is lower than the delivery pressure of the fuel delivery pump, not shown.

Die elektromagnetische Stellvorrichtung 7 wird durch nicht dargestellte, parallel zur Achse des Steuerventilkörpers 22 wirkende Schrauben mit dem Zwischenstück 41 gegen die Steuerventilbüchse 17 gespannt, ohne diese zu verspannen.The electromagnetic adjusting device 7 is clamped against the control valve sleeve 17 by screws (not shown), acting parallel to the axis of the control valve body 22, with the intermediate piece 41, without bracing the latter.

Der gesamte Niederdruckbereich des Steuerventils 2 wird durch Runddichtringe 45 abgedichtet.The entire low-pressure area of the control valve 2 is sealed by O-rings 45.

Die Brennstoffeinspritzvorrichtung funktioniert folgendermaßen:
   Beim Förderhub wird der Pumpenplunger 4 aus seiner unteren Totpunktlage in Richtung Steuerventileinheit 2 bewegt. Dabei schließt er nach Durchlaufen eines Vorhubes zunächst die Saug- und Absteuerbohrung 14. Danach fördert der Plunger 4 Brennstoff in die Hochdruckbohrung 12 und in die Hochdrucksteuerbohrung 28.The fuel injector works as follows:
During the delivery stroke, the pump plunger 4 is moved from its bottom dead center position in the direction of the control valve unit 2. After passing through a preliminary stroke, it first closes the suction and discharge bore 14. The plunger 4 then delivers fuel into the high-pressure bore 12 and into the high-pressure control bore 28.

Solange der Steuerventilkörper 22 mit dem Anschlagring 32 und der Ankerplatte 30 von der Feder 36 am Anschlag 35 gehalten wird, sind der Hochdruckringraum 26 und der Niederdruckringraum 27 über den Steuerventilsitz 25 verbunden. Dadurch strömt der geförderte Kraftstoff über die Absteuerbohrungen 29, den Ringraum 16 und die Rücklaufbohrung 15 in den Niederdruckraum 13 zurück.As long as the control valve body 22 with the stop ring 32 and the anchor plate 30 is held by the spring 36 at the stop 35, the high-pressure annular space 26 and the low-pressure annular space 27 are connected via the control valve seat 25. As a result, the delivered fuel flows back into the low-pressure chamber 13 via the control bores 29, the annular space 16 and the return bore 15.

Sobald die elektromagnetische Stellvorrichtung 7 durch einen Stromimpuls erregt wird, wird die Ankerplatte 39 angezogen. Dadurch wird der Steuerventilkörper 22 gegen den Steuerventilsitz 25 gezogen, wodurch die Förderung des Brennstoffs zum Entlastungsventil 6 und weiter über die nicht dargestellte Einspritzleitung zur nicht dargestellten Einspritzdüse beginnt.As soon as the electromagnetic actuating device 7 is excited by a current pulse, the armature plate 39 is attracted. As a result, the control valve body 22 is pulled against the control valve seat 25, as a result of which the delivery of the fuel to the relief valve 6 and further via the injection line (not shown) to the injection nozzle (not shown) begins.

Mit dem Anziehen der Ankerplatte 30 wird zugleich die Feder 36 vorgespannt. Sobald die elektromagnetische Stellvorrichtung 7 stromlos gemacht wird, hebt die Feder 36 den Steuerventilkörper 22 von seinem Sitz 25 ab. Dadurch strömt der Brennstoff wieder in die Niederdruckräume und die Brennstoffeinspritzung ist beendet.When the anchor plate 30 is tightened, the spring 36 is also preloaded. As soon as the electromagnetic actuating device 7 is de-energized, the spring 36 lifts the control valve body 22 from its seat 25. As a result, the fuel flows back into the low-pressure chambers and the fuel injection is ended.

Eine Voraussetzung für die präzise Funktion des Steuerventils 2 und damit für reproduzierbaren Förderbeginn und schwankungsfreie Fördermenge ist ein rückprallfreies Aufsetzen des Steuerventilkörpers 22 auf den Steuerventilsitz 25. Dies wird erfindungsgemäß erreicht durch eine fein abgestimmte Dämpfung der Bewegung des Steuerventilkörpers 22. Zur Dämpfung wird die Verdrängerströmung zwischen Ankerplatte 30 und der elektromagnetischen Stellvorrichtung 7 benutzt. Die Ankerplatte 30 ist ohne offene, axiale Bohrungen ausgeführt, um eine möglichst wirksame Quetschströmung am Hubende zwischen Ankerplatte 30 und elektromagnetische Stellvorrichtung 7 zu bewirken.A prerequisite for the precise function of the control valve 2 and thus for reproducible delivery start and fluctuation-free delivery quantity is a rebound-free placement of the control valve body 22 on the control valve seat 25. This is achieved according to the invention by a fine-tuned damping of the movement of the control valve body 22. For the damping, the displacement flow is between Anchor plate 30 and the electromagnetic actuator 7 used. The armature plate 30 is designed without open, axial bores in order to effect the most effective squeezing flow at the stroke end between the armature plate 30 and the electromagnetic actuating device 7.

Das erforderliche Maß der Dämpfung hängt unter anderem von der bewegten Masse ab, d. h. von der Masse des Steuerventilkörpers 22 + Ankerplatte 30 + Senkschraube 31 + Anschlagring 32 + Anteil der Masse der Feder 36. Ein weitere dämpfungsrelevanter Faktor ist die Federsteifigkeit des Steuerventilsitzes 25.The amount of damping required depends, among other things, on the moving mass, i. H. from the mass of the control valve body 22 + anchor plate 30 + countersunk screw 31 + stop ring 32 + proportion of the mass of the spring 36. Another factor relevant for damping is the spring stiffness of the control valve seat 25.

Die Dämpfung selbst hängt unter anderem von der Brennstoffviskosität, der Geometrie der Ankerplatte 30 und dem Mindestabstand 46 zwischen Ankerplatte 30 und elektromagnetischer Stellvorrichtung 7 sowie von dem Druck im Dämpfungsraum ab. Diese Einflußfaktoren müssen aufeinander abgestimmt werden. Die optimale Abstimmung ist erreicht, wenn das Aufsetzen des Steuerventilkörpers 22 auf den Steuerventilsitz 25 gerade rückschlagfrei erfolgt und die dämpfungsbedingte Verlangsamung der Bewegung des Steuerventilkörpers 22 minimiert ist.The damping itself depends, among other things, on the fuel viscosity, the geometry of the anchor plate 30 and the minimum distance 46 between the anchor plate 30 and the electromagnetic actuating device 7 and on the pressure in the damping chamber. These influencing factors have to be coordinated. The optimal adjustment is achieved when the control valve body 22 is placed on the control valve seat 25 without kickback and the damping-related slowdown in the movement of the control valve body 22 is minimized.

Die Versorgung des Dämpfungsraumes 33 mit Dämpfungsflüssigkeit, z. B. Dämpfungsöl, kann über einen gesonderten Dämpfungsölkreislauf erfolgen. Im vorliegenden Fall wird erfindungsgemäß Brennstoff aus dem Niederdruckbereich, speziell aus der Absteuerbohrung 29 des Steuerventils 2 entnommen und zwar über die Drosselbohrung 37. Letztere verhindert, daß die Druckstöße in der Absteuerbohrung 29 in den Dämpfungsraum 33 gelangen.The supply of the damping chamber 33 with damping liquid, for. B. damping oil, can be done via a separate damping oil circuit. In the present case Fuel according to the invention from the low-pressure region, specifically taken from the control bore 29 of the control valve 2, specifically via the throttle bore 37. The latter prevents the pressure surges in the control bore 29 from reaching the damping chamber 33.

Für ein einwandfreies Funktionieren der Dämpfung ist es wichtig, daß sich keine Luft im Dämpfungsraum 33 befindet, da hierdurch die Viskosität und Kompressibilität des Dämpfungsmediums beeinflußt werden. Außerdem ist es wichtig, daß die Dämpfungsflüssigkeit kontinuierlich erneuert wird, da diese sich erwärmt und altert.For proper functioning of the damping, it is important that there is no air in the damping space 33, since this affects the viscosity and compressibility of the damping medium. It is also important that the damping fluid is renewed continuously as it warms up and ages.

Erfindungsgemäß wird die Entlüftung des Dämpfungsraumes 33 über die Gewindebohrung 38 bewerkstelligt, die so angebracht ist, daß sie sich in Einbaulage des Steuerventils 2 im Bereich der höchsten Stelle des Dämpfungsraumes 33 befindet.According to the invention, the venting of the damping chamber 33 is accomplished via the threaded bore 38, which is provided in such a way that it is located in the installed position of the control valve 2 in the region of the highest point of the damping chamber 33.

An die Gewindebohrung 38 ist die Entlüftungs- bzw. Brennstoffrücklaufleitung 39 angeschlossen, durch die der Brennstoff über das Druckhalteventil 40 zurück zum nicht abgebildeten Brennstofftank fließt. Das Druckhalteventil 40 stellt einen bestimmten Flüssigkeitsdruck im Dämpfungsraum 33 sicher, der niedriger als der maximale Förderdruck der nicht dargestellten Niederdruckpumpe und niedriger als der Druck in den Niederdruckräumen der Brennstoffeinspritzvorrichtung ist. Dadurch wird eine Durchströmung des Dämpfungsraumes 33 und damit eine Erneuerung des Dämpfungsmediums Brennstoff und eine Kühlung des Steuerventils 2 sichergestellt. Außerdem bewirkt das Druckhalteventil 40, daß beim Stillstand des Motors der Dämpfungsraum 33 nicht leerlaufen kann, was zu ungedämpfter Hubbewegung und damit zu Sitzprellen des Steuerventils 3 führt.The vent or fuel return line 39 is connected to the threaded bore 38, through which the fuel flows back via the pressure holding valve 40 to the fuel tank, not shown. The pressure holding valve 40 ensures a certain liquid pressure in the damping chamber 33, which is lower than the maximum delivery pressure of the low-pressure pump, not shown, and lower than the pressure in the low-pressure chambers of the fuel injector. This ensures a flow through the damping chamber 33 and thus renewal of the damping medium fuel and cooling of the control valve 2. In addition, the pressure-maintaining valve 40 has the effect that the damping chamber 33 cannot run empty when the engine is at a standstill, which leads to undamped lifting movement and thus to bouncing of the control valve 3.

Dies hat u.a. einen falschen Förderbeginn beim Wiederanlassen des Motors zur Folge.This has among other things incorrect start of delivery when restarting the engine.

Das Lecköl aus dem Leckölraum 44 wird über die Lecköllängsbohrung 42 und die Leckölquerbohrung 43 im Steuerventilkörper 22 zum Federraum 34 und damit in den Dämpfungsölkreislauf geführt. Diese erfindungsgemäße Lösung erspart eine separate Leckölrückführleitung.The leak oil from the leak oil chamber 44 is guided via the leak oil longitudinal bore 42 and the leak oil cross bore 43 in the control valve body 22 to the spring chamber 34 and thus into the damping oil circuit. This solution according to the invention saves a separate leakage oil return line.

Für den Fall eines Versagens des Steuerventils 2 sorgt die Absteuernut 8 des Pumpenplungers 4 am Ende des Förderhubes für ein Absteuern des Brennstoffes in die Saug- bzw. Absteuerbohrung 14. Damit wird die Brennstoffeinspritzung in jedem Fall beendet, bevor die Förderung in den Kuppenbereich des Einspritzpumpennockens gelangt und diesen überbelastet.In the event of a failure of the control valve 2, the control groove 8 of the pump plunger 4 at the end of the delivery stroke ensures control of the fuel in the suction or control bore 14. The fuel injection is ended in any case before the delivery into the top area of the injection pump cam arrives and overloaded it.

Der Pumpenplunger 4 des Einspritzpumpenelements 1 ist erheblich einfacher zu fertigen; als der des Normalelementes 1a, da die Verdreheinrichtung und die präzisen Steuerkanten entfallen.The pump plunger 4 of the injection pump element 1 is considerably easier to manufacture; than that of the normal element 1a, since the twisting device and the precise control edges are eliminated.

Die erfindungsgemäße Brennstoffeinspritzvorrichtung gestattet eine genaue Bestimmung von Förderbeginn und Dosierung der Brennstoffeinspritzmenge durch das rückprallfreie Aufsetzen des Steuerventilkörpers 22 auf den Steuerventilsitz 25. Außerdem ist sie fertigungs- und servicefreundlich, da die Hauptkomponenten Einspritzpumpenelement 1, Steuerventil 2 und elektromagnetische Stellvorrichtung 7 einzeln und unabhängig voneinander zu fertigen, zu prüfen und auszutauschen sind.The fuel injection device according to the invention allows a precise determination of the start of delivery and metering of the fuel injection quantity by the rebound-free placement of the control valve body 22 on the control valve seat 25. In addition, it is easy to manufacture and service, since the main components of the injection pump element 1, control valve 2 and electromagnetic actuating device 7 are independent of one another manufacture, check and replace.

Claims (11)

  1. A fuel injection device for internal combustion engines, preferably diesel engines, comprising at least one injection pump element (1) having a sleeve (5) in which a pump plunger (4) is axially guided and seals off a high-pressure chamber (11), the device also comprising a control valve(2) placed between the high-pressure chamber (11) and a relief valve (6) and having a sleeve (17) in which a control-valve body (22), the motion of which is damped, is axially movable by an electromagnetic adjusting device (7) in combination with a spring (36), an annular low-pressure chamber (27) disposed in the control-valve sleeve (17) being connected to a low-pressure chamber (13) and a stepped bore (19) for receiving the control valve (2) being provided in the plunger sleeve (5) at a slight distance above the high-pressure chamber (11), the stepped bore being perpendicular and central relative to the axis of the pump plunger (4),
    characterised in that an armature plate (30) is secured to one end of the control-valve body (22) and is in operative connection with the electromagnetic adjusting device (7) and is disposed in a liquid-filled damping chamber (33) which is bounded by the electromagnetic adjusting device (7), so that the motion of the armature plate (30) results in a damping displacement flow between it and the electromagnetic adjusting device (7).
  2. A fuel injection device according to claim 1,
    characterised in that the damping chamber (33) is filled with fuel, a choke bore (37) is placed between the damping chamber (33) and the chambers conveying low pressure, and a vent or fuel return pipe (38) is connected near the highest place in the damping chamber (33).
  3. A fuel injection device according to claim 2,
    characterised in that a pressure-maintaining valve (40) is disposed in the vent or fuel return pipe (39), the valve opening pressure being lower than the pressure in the low-pressure chambers of the injection pump element (1).
  4. A fuel injection device according to any of the preceding claims, characterised in that the armature plate (30) is solid and, at a given mass of the moving parts of the control valve element (3), the force of the spring (27), the shape of the armature plate (30), the viscosity of the fuel in the operating temperature range, the force of the electromagnetic adjusting device, and the gap between the armature plate (30) and the electromagnetic adjusting device (7) in the attracted position are so adjusted to one another that the control valve body (22) comes to rest on a seat (25) without rebounding
  5. A fuel injection device according to any of the preceding claims, characterised in that a leakage-oil longitudinal bore (42) and a leakage-oil transverse bore (43) are formed in the control valve body (22).
  6. A fuel injection device according to any of the preceding claims, characterised in that the outer contour of the injection pump element (1), starting from a flange (18), corresponds exactly to the contour of a normal pump element (1a) having comparable parameters.
  7. A fuel injection device according to any of the preceding claims, characterised in that the high-pressure chamber (11) extends above the pump element flange (18) and the suction or shut-off bore (14) starting from the low-pressure chamber (13) is adapted to the position of the high-pressure chamber (11).
  8. A fuel injection device according to any of the preceding claims, characterised in that the control valve (2) is disposed with sliding fit in the stepped bore (19).
  9. A fuel injection device according to any of the preceding claims, characterised in that sealing elements (20) are disposed on both sides of a high-pressure control bore (28) between the control valve sleeve (17) and the stepped bore (19).
  10. A fuel injection device according to any of the preceding claims, characterised in that the connection between the annular low-pressure chamber (27) and the low-pressure chamber (13) is a return bore (15) in the plunger sleeve (5).
  11. A fuel injection device according to any of the preceding claims, characterised in that a shut-off groove (8) is formed on the pump plunger (4) and, at the end of the delivery stroke, connects the high-pressure chamber (11) to a suction or shut-off bore (14), via a longitudinal shut-off bore (9) and a transverse shut-off bore (10).
EP89122631A 1988-12-09 1989-12-08 Fuel injection device Expired - Lifetime EP0372562B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT89122631T ATE82043T1 (en) 1988-12-09 1989-12-08 FUEL INJECTOR.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3841462A DE3841462C2 (en) 1988-12-09 1988-12-09 Fuel injector
DE3841462 1988-12-09

Publications (2)

Publication Number Publication Date
EP0372562A1 EP0372562A1 (en) 1990-06-13
EP0372562B1 true EP0372562B1 (en) 1992-11-04

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP89122631A Expired - Lifetime EP0372562B1 (en) 1988-12-09 1989-12-08 Fuel injection device

Country Status (4)

Country Link
US (1) US5106019A (en)
EP (1) EP0372562B1 (en)
AT (1) ATE82043T1 (en)
DE (2) DE3841462C2 (en)

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Also Published As

Publication number Publication date
DE3841462C2 (en) 1996-05-30
DE3841462A1 (en) 1990-06-13
US5106019A (en) 1992-04-21
ATE82043T1 (en) 1992-11-15
DE58902618D1 (en) 1992-12-10
EP0372562A1 (en) 1990-06-13

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