EP0386175A1 - Fuel injection pump for internal combustion engines. - Google Patents

Fuel injection pump for internal combustion engines.

Info

Publication number
EP0386175A1
EP0386175A1 EP19890906727 EP89906727A EP0386175A1 EP 0386175 A1 EP0386175 A1 EP 0386175A1 EP 19890906727 EP19890906727 EP 19890906727 EP 89906727 A EP89906727 A EP 89906727A EP 0386175 A1 EP0386175 A1 EP 0386175A1
Authority
EP
European Patent Office
Prior art keywords
pressure
valve
fuel injection
injection pump
control
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP19890906727
Other languages
German (de)
French (fr)
Other versions
EP0386175B1 (en
Inventor
Josef Hain
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP0386175A1 publication Critical patent/EP0386175A1/en
Application granted granted Critical
Publication of EP0386175B1 publication Critical patent/EP0386175B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D1/00—Controlling fuel-injection pumps, e.g. of high pressure injection type
    • F02D1/16—Adjustment of injection timing
    • F02D1/18—Adjustment of injection timing with non-mechanical means for transmitting control impulse; with amplification of control impulse
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D1/00—Controlling fuel-injection pumps, e.g. of high pressure injection type
    • F02D1/16—Adjustment of injection timing
    • F02D1/18—Adjustment of injection timing with non-mechanical means for transmitting control impulse; with amplification of control impulse
    • F02D1/183—Adjustment of injection timing with non-mechanical means for transmitting control impulse; with amplification of control impulse hydraulic
    • 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
    • F02M41/00—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor
    • F02M41/08—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined
    • F02M41/10—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor
    • F02M41/12—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor the pistons rotating to act as the distributor
    • F02M41/123—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor the pistons rotating to act as the distributor characterised by means for varying fuel delivery or injection timing
    • F02M41/128—Varying injection timing by angular adjustment of the face-cam or the rollers support

Definitions

  • the invention relates to a fuel injection pump according to the preamble of the main claim.
  • a fuel injection pump is known from DE-OS 3148 214, in which the control pressure which changes the start of injection and is normally proportional to the speed can be changed by the pressure valve which operates in dependence on the pressure and temperature. By means of this pressure valve, the start of spraying is postponed so far in the cold start that there is sufficient time for the preparation of the fuel and a correspondingly better ignition or combustion takes place.
  • the fuel injection pump according to the invention with the characterizing features of the main claim has the advantage that the KSB function can be ensured by a back pressure in the drain line.
  • FIG. 1 shows a schematic illustration of the pressure holding valve of a fuel injection pump
  • Figure 2 shows the pressure curve with KSB function in comparison to the normal function
  • a distributor injection pump is shown with a feed pump 1, which runs synchronously with the speed of the internal combustion engine.
  • the feed pump 1 draws fuel from a fuel tank 49 via the feed pump suction line 48 and feeds it via a pressure line 2, a distributor 6 and a connecting line 5 into a suction space 14 of the fuel injection pump, from which there is no shown the actual fuel injection pump is supplied with fuel.
  • the suction chamber 14 is connected via a bore 15 in an adjusting piston 11 to a working chamber 12 delimited by the latter in a cylinder of an injection start adjustment device 9.
  • a connecting line 3 branches off from the distributor 6 and leads to a pressure chamber 18 of a pressure control valve 7.
  • the pressure control valve 7 controls the fuel pressure downstream of the feed pump 1, that is to say also the pressure in the suction chamber 14 as a control pressure as a function of the speed, the control pressure increasing proportionally with increasing speed.
  • the adjusting piston 11 is displaced against a return spring 13 in accordance with the control pressure and engages with a bolt 10 in the cam drive of the fuel injection pump (not shown further here) for adjusting the start of injection.
  • the start of spraying during normal operation of the internal combustion engine or warm internal combustion engine is adjusted to "early" with increasing speed.
  • the start of spraying at the start and at a low engine speed must be set earlier than in the case of a warm engine in order to achieve a perfect start, that is to say a quick start-up of the engine with the lowest possible blue smoke emission .
  • the interior pressure is raised.
  • the pressure control valve 7 has a piston 16 which is tightly displaceable in a closed cylinder 110 and which, as a movable wall, separates the pressure chamber 18 from a reset chamber 21 and is acted upon by a return spring 17 arranged in the reset chamber 21 against the control pressure to be set in the pressure chamber 18.
  • the piston 16 controls with a control edge a discharge cross-section of a discharge opening 19 of a discharge line 20 leading from the cylindrical wall of the cylinder 110 from the pressure chamber 18 to a relief rough area.
  • Pressure chamber 18 and reset chamber 21 are connected to one another via a constant throttle 22, which is preferably provided in the piston 16.
  • the reset space 21 can be relieved via a relief line 24.
  • An increase in pressure requires a reduction in the control cross section at the control opening 19 of the pressure control valve 7 for the amount of fuel flowing through the drain line 20.
  • the drain line 20 leading away from the cutoff opening 19 opens into a pressure holding valve cylinder 111 of a pressure holding valve 50.
  • the fuel flowing out of the control opening 19 flows through this drain line 20 and is in contact with a closing member 51 which is arranged in the cylinder 111 of the pressure holding valve 50 .
  • the closing member here a ball 51, is pressed by a closing spring 52 on a valve seat which is arranged in the opening of the outlet line 20 in the cylinder 111.
  • the closing spring 52 which is accommodated in a spring chamber 55 arranged in the cylinder 111, bears on the side facing away from the closing member 51 against a support member in the form of a piston 53 which is preferably axially adjustable between two stops 87 and 88 in the cylinder 111.
  • the adjustable piston 53 is acted upon by fuel pressure on the side opposite the closing spring 52, which is connected via a connecting line 56 which is connected to the relief line 24 upstream of a pressure valve 23 arranged in the relief line 24. This fuel pressure is also present in the reset space 21.
  • An outlet line 57 leads from the spring chamber 55 of the cylinder 111 of the pressure valve 50 and opens into the feed pump suction line 48.
  • the pressure valve 23 is arranged in the relief line 24, which leads away from the resetting space 21 of the pressure control valve 7.
  • the relief line 24 leads to a control chamber 25 of the pressure valve 23.
  • An actuating member 26 of a temperature-dependent element projects into the control chamber 25 27, for example an expansion element or a bimetal spring.
  • the actuating member 26 engages a movable valve closing member 28 arranged in the pressure valve 23 and loaded by a return spring 29 arranged in a spring chamber 30.
  • the valve closing member 28 is only moved by the actuating member 26 in the open position of the pressure valve 23 when the temperature-dependent working element 27 is activated, ie only at the minimum operating temperature of the internal combustion engine.
  • a control line 32 branches off from the relief line 24 upstream of the connection to the pressure valve 23, which leads to a KSB control valve 8 and opens there via an inlet opening 33 in the peripheral wall of a KSB cylinder 35 of the KSB control valve 8.
  • a connecting line 4 coming from the distributor 6 leads into a pressure chamber 39 bounded by the front end of the KSB cylinder 35 on the one hand.
  • the pressure chamber 39 is on the other hand from an end side of an axially displaceable in the KSB cylinder 35 from one to another adjustable stop 37 supporting compression spring 36 limits the control piston 34.
  • In the control piston 34 there is an annular groove 41, one boundary edge of which forms a control edge which controls the inlet opening 33.
  • the annular groove 41 is connected by radial bores 42 to a blind bore 43 arranged axially in the control piston 34, which starts from the other end of the control piston 34, which is acted upon by the compression spring 36 and closes a spring chamber 40 in the KSB cylinder. From the spring chamber 40 there is a connecting line 45 to the spring chamber 30 of the pressure valve 23. From this connecting line 45 a drain line 47 branches off, which is connected to the feed pump suction line 48.
  • the object according to FIG. 1 results in a function of a speed / pressure characteristic as can be seen in FIG. 2.
  • the object according to FIG. 1 works as follows: If the internal combustion engine is started below the operating temperature, the actuating member 26 is lifted off the valve closing member 28 and the pressure valve 23 is closed. The adjusting piston 11 is in the "late position" until the starting speed is reached. As a result of the closed pressure control valve 7 with the pressure holding valve 50 being closed at the same time, no fuel can flow away, so that a control pressure builds up quickly in the suction chamber 14 and the working chamber 12, which causes the adjusting piston 11 to be displaced into the "early position".
  • the pressure holding valve 50 opens when a set opening pressure is reached.
  • the fuel can now - if the piston 16 of the pressure control valve 7 cannot completely close the control opening 19 from the structural conditions and specifications for the course of the control pressure change over the speed when the pressure is compensated by the closed pressure valve 23 and the throttle 22 - via the Discharge opening 19, the drain line 20 flow past the closing member 51 of the pressure control valve 50 into the spring chamber 55.
  • the fuel flows from the spring chamber 55 via the drain line 57 into the feed pump suction line 48.
  • the pressure initially remains almost constant after the pressure holding valve 50 is opened, but then increases as the feed pump 1 increases further in accordance with the characteristic curve section 63.
  • the throttling of the partially open control section 19 in V. m. the increased delivery rate of the delivery pump 1 in such a way that a desired increase in the control pressure is achieved in spite of the outflow of a small amount of fuel in order to achieve the required early adjustment of the start of injection when the internal combustion engine is cold and not yet warm.
  • the fuel pressure is controlled on the one hand by the control cross section at the control opening 19 and on the other hand by the opening pressure of the closing element 51, which opens against the force of the closing spring 52.
  • the closing force of the closing spring 52 which is supported on the piston 53, which is acted upon by the pressure prevailing in the relief line 24, can now also be influenced in such a way that the opening pressure of the pressure-maintaining valve 50 increases as the pressure in the return space 21 of the pressure control valve 7 increases Which pressure is simultaneously the pressure in the pressure chamber 18 of the pressure-maintaining valve 7 and the working chamber 12 of the spray adjustment device 9 when the pressure valve 23 is still closed. If the piston 53 comes to its spring-side stop 87, the increase in opening pressure is ended. The point 62 corresponds to this opening pressure.
  • the pressure-maintaining valve has an opening pressure which is determined by the other stop 88 of the piston 53 and which cannot be changed , but can also be adjustable.
  • the KSB control valve 8 with the annular groove 41 on the control piston 34 displaced by the control pressure 34 begins to open the inlet opening 33 in accordance with an opening pressure which can be finely adjusted at the stop 37.
  • the KSB valve 8 serves as a pressure-dependent device via which it passes through the control edges of the annular groove 41 and Cylinder opening 33 comes to an increasing relief, through which the control pressure curve 60 approaches the control pressure curve 64 when the internal combustion engine is at operating temperature.
  • a characteristic curve p / n can be seen from characteristic curve 65, which would occur without the pressure holding valve 50 according to the invention. At low speed, the pressure does not rise as steeply as the speed with the pressure-maintaining valve 50 according to the invention. At higher speeds, the characteristic curves 60 and 65 have almost the same course, controlled by the KSB control valve 8. The same pressure / speed behavior also results from an arrangement according to FIG. 3.
  • FIG. 3 shows an alternative arrangement of the rest of the same structure.
  • a pressure-maintaining valve 50a has a valve piston 66, which acts as a closing element, is loaded with a closing spring 67 which can be set in the pretension and delimits a pressure chamber 89 in the valve housing 70a at the end, into which the discharge line 20 opens and which is controlled by the end face of the valve piston leads a connecting line 90 to the feed pump suction line 48.
  • the closing spring 67 rests on the side opposite the valve piston 66 against a support member 69 which is axially movable in the valve cylinder 70a of the pressure-maintaining valve 50.
  • the support member 69 can be adjusted by an electrically controllable device 68.
  • the electrical device 68 is controlled by control signals which are formed by a speed-sensing measuring device or by a pressure sensor.
  • the opening pressure of the pressure-maintaining valve 50a is controlled in accordance with the rotational speed or the pressure, upon reaching which a control opening 71 provided in the valve cylinder 70a, which establishes a connection between the discharge line 20 and the connecting line 90, is opened or closed.
  • this control pressure valve 50a can be used to modify the control pressure according to operating parameters of the internal combustion engine even when the internal combustion engine is warm.
  • FIG. 4 shows a pressure holding valve 50b with a valve cylinder 70b, from one end face 72 of which a connecting line 73 leads to the connecting line 3b, which comes from the feed pump 1.
  • a valve piston 74 slides axially displaceably in the valve cylinder 70b and acts as a closing member, which delimits a pressure chamber 89a with the end face 72 in the valve cylinder 70b and has an annular groove 75 in the lateral surface, one boundary edge of which (121) serves as the control edge.
  • this closing spring 76 presses on a piston 77, which is also axially displaceable in the valve cylinder 70b and forms a pressure chamber 61 to the second end face 79 of the valve cylinder 70b. From this second end face 79, a connecting line 78 leads to the relief line 24b, upstream of the pressure valve 23.
  • two control openings are arranged, one of which the control opening 81 is constantly connected to the annular groove and at the same time to the delivery pump suction line 48 connected is.
  • the discharge line 20 of the pressure control valve 7 enters the other control opening 80, which is arranged approximately in the middle of the valve cylinder 70b.
  • This Ab ⁇ control opening 80 is arranged so that the annular groove 75 at the start of the feed pump 1 has no overlap with the control opening 80, consequently no fuel can drain and no pressure is released.
  • a pressure is generated by the feed pump 1, which builds up via the connecting line 3b, in the connecting line 73 and in the pressure chamber 18b of the pressure control valve 7 and which, analogously to the above exemplary embodiments, leads to a steep rise in control pressure and early adjustment of the start of injection when the pressure holding valve 50b is closed .
  • the valve piston 74 is acted upon by the control pressure to be set and would move axially, and the drain line 20 would open up via the annular groove 75 if the control pressure in the reset space 21b were not via the throttle 22b when the pressure valve 23 was closed also reaches the pressure chamber 61 via the relief line 24b and the connecting line 78.
  • This control pressure is therefore also present on the piston 77, which is larger in diameter than the valve piston 74, and presses on the valve piston 74 via the piston 77 and the closing spring 76, which can be set in the prestress.
  • the opening pressure of the pressure control valve 50b is influenced, depending on the steep pressure rise of the control pressure to be controlled.
  • the opening pressure can be limited by a stop 87a which limits the path of the piston 77 in the direction of the closing spring 76.
  • FIG. 5 shows a valve piston 86 operating as a closing member, which corresponds to the valve piston 74 of FIG. 4.
  • the pressure-controllable piston 77 from FIG. 4 is replaced by an electrically controllable device 68a, which corresponds to that of the device 68 from FIG.
  • the pressure is consequently measured by means of a pressure sensor, which gives a control signal for the electrically controllable device.

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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)
  • High-Pressure Fuel Injection Pump Control (AREA)

Abstract

Afin d'augmenter la pente de la courbe caractéristique de la pression et de la vitesse de rotation, une pompe d'injection de carburant pour moteurs à combustion interne comprend une soupape réglable (50) de maintien de la pression agencée dans le conduit de décharge (20) qui mène de la soupape (7) de commande de la pression jusqu'au conduit terminal (24) qui part de la chambre à ressort (21). Différents modes de réalisation de la soupape (50) de maintien de la pression permettent d'obtenir différentes courbes caractéristiques de la pression et de la vitesse de rotation qui génèrent une pression relativement élevée à une vitesse de rotation réduite et assurent ainsi un démarrage à froid plus rapide.In order to increase the slope of the characteristic curve of the pressure and the speed of rotation, a fuel injection pump for internal combustion engines comprises an adjustable pressure maintenance valve (50) arranged in the discharge duct. (20) which leads from the pressure control valve (7) to the terminal conduit (24) which leaves from the spring chamber (21). Different embodiments of the pressure maintenance valve (50) make it possible to obtain different characteristic curves of the pressure and the rotation speed which generate a relatively high pressure at a reduced rotation speed and thus ensure a cold start. faster.

Description

Kraftstoffeinspritzpumpe für Brennkraftmaschinef-Fuel injection pump for internal combustion engine
Stand der TechnikState of the art
Die Erfindung geht aus von einer Kraftstoffeinspritzpumpe nach der Gattung des Hauptanspruchs. Aus DE-OS 3148 214 ist eine Kraftstoff¬ einspritzpumpe bekannt, bei der der den Spritzbeginn ändernde, nor¬ malerweise drehzahlproportionale Steuerdruck durch das druck- und temperaturabhängig arbeitende Druckventil änderbar ist. Durch dieses Druckventil wird beim Kaltstart der Spritzbeginn so weit nach früh verschoben, daß dadurch für die Aufbereitung des Kraftstoffs genü¬ gend Zeit bleibt und eine entsprechend bessere Zündung bzw. Verbren¬ nung erfolgt.The invention relates to a fuel injection pump according to the preamble of the main claim. A fuel injection pump is known from DE-OS 3148 214, in which the control pressure which changes the start of injection and is normally proportional to the speed can be changed by the pressure valve which operates in dependence on the pressure and temperature. By means of this pressure valve, the start of spraying is postponed so far in the cold start that there is sufficient time for the preparation of the fuel and a correspondingly better ignition or combustion takes place.
Nachteilig ist, daß bei ungünstiger Konstellation am Drucksteuerven¬ til bereits beim Stillstand der Einspritzpumpe ein kleiner Spalt der Absteueröffnung freigegeben sein kann und beim Anlauf der Kraft¬ stoffeinspritzpumpe der Förderpu penliefergrad dann nicht ausreicht, den erforderlichen Druck bei niederen Drehzahlen im Rückstellraum bei geschlossenem Druckventil für die Kaltstartfrühverstellung des Spritzbeginns beim Kaltstart der Brennkraftmaschine aufzubauen (KSB-Funktion). Vorteile der ErfindungIt is disadvantageous that, in the case of an unfavorable constellation on the pressure control valve, a small gap in the discharge opening can be released when the injection pump is at a standstill, and when the fuel injection pump starts, the delivery rate is then insufficient to supply the required pressure at low speeds in the recovery space with the pressure valve closed to set up the cold start early adjustment of the start of spraying when the internal combustion engine starts cold (KSB function). Advantages of the invention
Die erfindungsgemäße Kraftstoffeinspritzpumpe mit den kennzeichnen¬ den Merkmalen des Hauptanspruchs hat demgegenüber den Vorteil, daß durch einen Gegendruck in der Ablaufleitung die KSB-Funktion sicher¬ gestellt werden kann.The fuel injection pump according to the invention with the characterizing features of the main claim has the advantage that the KSB function can be ensured by a back pressure in the drain line.
Durch die in den Unteransprüchen aufgeführten Maßnahmen sind vor¬ teilhafte Weiterbildungen und Verbesserungen, der im Hauptanspruch angegebenen Kraftstoffeinspritzpumpe möglich. Der Gegendruck, der durch das Druckhalteventil in der Ablaufleitung erzeugt wird, kann durch verschiedene Ventilausführungen vorgenommen werden, so daß auch eine Drucksteigerungskorrektur bei Normalfunktion - ohne KSB - möglich ist.Advantageous further developments and improvements of the fuel injection pump specified in the main claim are possible through the measures listed in the subclaims. The back pressure that is generated by the pressure maintaining valve in the drain line can be carried out by different valve designs, so that a pressure increase correction with normal function - without KSB - is possible.
Zeichnungdrawing
Mehrere Ausführungsbeispiele der Erfindung sind in der Zeichnung vereinfacht dargestellt und im folgenden näher beschrieben.Several embodiments of the invention are shown in simplified form in the drawing and described in more detail below.
Es zeigen Figur 1 eine schematische Darstellung des Druckhalteven¬ tils einer Kraftstoffeinspritzpumpe; Figur 2 den Druckverlauf bei KSB-Funktion im Vergleich zur Normalfunktion und Figuren 3, 4, 5 verschiedene Druckhaiteventi1ausführungen.FIG. 1 shows a schematic illustration of the pressure holding valve of a fuel injection pump; Figure 2 shows the pressure curve with KSB function in comparison to the normal function and Figures 3, 4, 5 different Druckhaiteventi1ausführung.
Beschreibung der AusführungsbeispieleDescription of the embodiments
In Figur 1 ist eine Verteilereinspritzpumpe mit einer Förderpumpe 1, die drehzahlsynchron zur Brennkraftmaschine läuft, dargestellt. Die Förderpumpe 1 saugt aus einem Kraftstoffbehälter 49 Kraftstoff über die Förderpumpensaugleitung 48 an und fördert ihn über eine Druckleitung 2, einen Verteiler 6 und eine Verbindungsleitung 5 in einen Saugraum 14 der Kraftstoffeinspritzpumpe, aus welchem in nicht dargestellter Weise die eigentliche Kraftstoffeinspritzpumpe mit Kraftstoff versorgt wird. Der Saugraum 14 ist über eine Bohrung 15 in einem Verstellkolben 11 mit einem von diesem in einem Zylinder einer Spritzbeginnverstelleinrichtung 9 begrenzten Arbeitsraum 12 verbunden. Vom Verteiler 6 zweigt auch eine Verbindungsleitung 3 ab, die zu einem Druckraum 18 eines Drucksteuerventils 7 führt. Durch das Drucksteuerventil 7 wird der stromabwärts der Förderpumpe 1 herrschende Kraftstoffdruck, also auch der Druck im Saugraum 14 als Steuerdruck drehzahlabhängig gesteuert, wobei mit zunehmender Dreh¬ zahl der Steuerdruck proportional steigt. Der Verstellkolben 11 wird entsprechend dem Steuerdruck gegen eine Rückstellfeder 13 verschoben und greift dabei mit einem Bolzen 10 in den hier nicht weiter ge¬ zeigten Nockenantrieb der Kraftstoffeinspritzpumpe zur Spritzbeginn¬ verstellung ein. Dabei wird der Spritzbeginn bei Normalbetrieb der Brennkraftmaschine bzw. betriebswarmer Brennkraftmaschine mit zuneh¬ mender Drehzahl nach "früh" verstellt. Aufgrund der geringen Zünd- willigkeit des Kraftstoffs bei kaltem Motor muß, um einen einwand¬ freien Start, d. h. ein schnelles Hochlaufen des Motors bei mög¬ lichst geringer Blaurauchemission zu erreichen, der Spritzbeginn beim Start und bei niederer Drehzahl früher eingestellt werden als bei warmem Motor. Um auch bei niederen Drehzahlen, also schon im Startbereich, eine Frühverstellung zu erzielen, wird der Innenraum- druck angehoben.In Figure 1, a distributor injection pump is shown with a feed pump 1, which runs synchronously with the speed of the internal combustion engine. The feed pump 1 draws fuel from a fuel tank 49 via the feed pump suction line 48 and feeds it via a pressure line 2, a distributor 6 and a connecting line 5 into a suction space 14 of the fuel injection pump, from which there is no shown the actual fuel injection pump is supplied with fuel. The suction chamber 14 is connected via a bore 15 in an adjusting piston 11 to a working chamber 12 delimited by the latter in a cylinder of an injection start adjustment device 9. A connecting line 3 branches off from the distributor 6 and leads to a pressure chamber 18 of a pressure control valve 7. The pressure control valve 7 controls the fuel pressure downstream of the feed pump 1, that is to say also the pressure in the suction chamber 14 as a control pressure as a function of the speed, the control pressure increasing proportionally with increasing speed. The adjusting piston 11 is displaced against a return spring 13 in accordance with the control pressure and engages with a bolt 10 in the cam drive of the fuel injection pump (not shown further here) for adjusting the start of injection. The start of spraying during normal operation of the internal combustion engine or warm internal combustion engine is adjusted to "early" with increasing speed. Due to the low ignitability of the fuel when the engine is cold, the start of spraying at the start and at a low engine speed must be set earlier than in the case of a warm engine in order to achieve a perfect start, that is to say a quick start-up of the engine with the lowest possible blue smoke emission . In order to achieve an early adjustment even at low engine speeds, ie already in the start area, the interior pressure is raised.
Das Drucksteuerventil 7 weist einen in einem geschlosssenen Zylinder 110 dicht verschiebbaren Kolben 16 auf, der als bewegliche Wand den Druckraum 18 von einem Rückstellraum 21 trennt und von einer im Rückstellraum 21 angeordneten Rückstellfeder 17 gegen den im Druckraum 18 herrschenden, einzustellenden Steuerdruck beaufschlagt ist. Der Kolben 16 steuert dabei mit einer Steuerkante einen Absteuerquerschnitt einer Absteueröffnung 19 einer von der zylindri¬ schen Wand des Zylinders 110 vom Druckraum 18 zu einem Entlastungs- rau abführenden Ablaufleitung 20. Druckraum 18 und Rückstellraum 21 sind über eine konstante Drossel 22 miteinander verbunden, die vor¬ zugsweise im Kolben 16 vorgesehen ist. Der Rückstellraum 21 ist über eine Entlastungsleitung 24 entlastbar.The pressure control valve 7 has a piston 16 which is tightly displaceable in a closed cylinder 110 and which, as a movable wall, separates the pressure chamber 18 from a reset chamber 21 and is acted upon by a return spring 17 arranged in the reset chamber 21 against the control pressure to be set in the pressure chamber 18. The piston 16 controls with a control edge a discharge cross-section of a discharge opening 19 of a discharge line 20 leading from the cylindrical wall of the cylinder 110 from the pressure chamber 18 to a relief rough area. Pressure chamber 18 and reset chamber 21 are connected to one another via a constant throttle 22, which is preferably provided in the piston 16. The reset space 21 can be relieved via a relief line 24.
Eine Druckerhöhung erfordert eine Verkleinerung des Absteuerquer¬ schnitts an der Absteueröffnung 19 des Drucksteuerventils 7 für die durch die Ablaufleitung 20 abfließende Kraftstoffmenge. Die von der Absteueröffnung 19 wegführende Ablaufleitung 20 mündet in einem Druckhalteventil-Zylinder 111 eines Druckhalteventils 50. Durch diese Ablaufleitung 20 fließt der aus der Äbsteueröffnung 19 aus¬ fließende Kraftstoff und liegt an einem Schließglied 51 an, das im Zylinder 111 des Druckhalteventils 50 angeordnet ist. Das Schlie߬ glied, hier eine Kugel 51 wird durch eine Schließfeder 52 an einem Ventilsitz, der in der Einmündung der Ablaufleitung 20 in den Zylin¬ der 111 angeordnet ist, gepreßt. Die Schließfeder 52, die in einem im Zylinder 111 angeordneten Federraum 55 untergebracht ist, liegt auf der dem Schließglied 51 abgewandten Seite an einem Stützglied in Form eines im Zylinder 111 vorzugsweise zwischen zwei Anschlägen 87 und 88 axial verstellbaren Kolben 53 an. Der verstellbare Kolben 53 ist auf der der Schließfeder 52 gegenüberliegenden Seite mit Kraft¬ stoffdruck beaufschlagt, der über eine Verbindungsleitung 56, die mit der Entlastungsleitung 24 stromaufwärts eines in der Entla¬ stungsleitung 24 angeordneten Druckventils 23 verbunden ist. Dieser Kraftstoffdruck steht auch im Rückstellraum 21 an. Aus dem Federraum 55 des Zylinders 111 des Druckventils 50 führt eine Ablaufleitung 57, die in die Förderpumpensaugleitung 48 mündet.An increase in pressure requires a reduction in the control cross section at the control opening 19 of the pressure control valve 7 for the amount of fuel flowing through the drain line 20. The drain line 20 leading away from the cutoff opening 19 opens into a pressure holding valve cylinder 111 of a pressure holding valve 50. The fuel flowing out of the control opening 19 flows through this drain line 20 and is in contact with a closing member 51 which is arranged in the cylinder 111 of the pressure holding valve 50 . The closing member, here a ball 51, is pressed by a closing spring 52 on a valve seat which is arranged in the opening of the outlet line 20 in the cylinder 111. The closing spring 52, which is accommodated in a spring chamber 55 arranged in the cylinder 111, bears on the side facing away from the closing member 51 against a support member in the form of a piston 53 which is preferably axially adjustable between two stops 87 and 88 in the cylinder 111. The adjustable piston 53 is acted upon by fuel pressure on the side opposite the closing spring 52, which is connected via a connecting line 56 which is connected to the relief line 24 upstream of a pressure valve 23 arranged in the relief line 24. This fuel pressure is also present in the reset space 21. An outlet line 57 leads from the spring chamber 55 of the cylinder 111 of the pressure valve 50 and opens into the feed pump suction line 48.
Zur temperaturabhängigen Beeinflussung des Kraftstoffdrucks beim Starten der Brennkraftmaschine ist in der Entlastungsleitung 24, die vom Rückstellraum 21 des Drucksteuerventils 7 wegführt, das Druck¬ ventil 23 angeordnet. Die Entlastungsleitung 24 führt zu einem Ab¬ steuerraum 25 des Druckventils 23. In den Absteuerraum 25 ragt ein Betätigungsglied 26 eines temperaturabhängig arbeitenden Elements 27, beispielsweise eines Dehnstoffelements oder einer Bimetallfeder. Das Bet tigungsglied 26 greift an einem im Druckventil 23 angeordne¬ ten beweglichen, von einer in einem Federraum 30 angeordneten Rück¬ stellfeder 29 belasteten Ventilschließglied 28 an. Das Ventil¬ schließglied 28 wird nur bei angesteuertem temperaturabhängig arbei¬ tenden Element 27, d. h. nur bei Mindestbetriebstemperatur der Brennkraftmaschine durch das Betätigungsglied 26 in Öffnungsstellung des Druckventils 23 bewegt. Von der Entlastungsleitung 24 zweigt stromaufwärts der Verbindung mit dem Druckventil 23 eine Steuerlei¬ tung 32 ab, die zu einem KSB-Regelventil 8 führt und dort über eine Eintrittsöffnung 33 in der Umfangswand eines KSB-Zylinders 35 des KSB-Regelventils 8 mündet. In einen von der Stirnseite des KSB-Zy¬ linders 35 einerseits begrenzten Druckraum 39 den KSB-Zylinder führt eine vom Verteiler 6 kommende Verbindungsleitung 4. Der Druckraum 39 wird andererseits von einer Stirnseite eines im KSB-Zylinder 35 axial verschiebbaren von einer sich an einem einstellbaren An¬ schlag 37 abstützenden Druckfeder 36 belasteten Steuerkolben 34 be¬ grenzt. Im Steuerkolben 34 ist eine Ringnut 41 angeordnet, deren eine Begrenzungskante eine die Eintrittsöffnung 33 steuernde Steuer¬ kante bildet. Die Ringnut 41 ist durch Radialbohrungen 42 mit einer im Steuerkolben 34 axial angeordneten Sackbohrung 43 verbunden, die von der anderen von der Druckfeder 36 beaufschlagten, einen Feder¬ raum 40 im KSB-Zylinder abschließenden Stirnseite des Steuerkolbens 34 ausgeht. Vom Federraum 40 besteht eine Verbindungsleitung 45 zu dem Federraum 30 des Druckventils 23. Von dieser Verbindungsleitung 45 zweigt eine Abflußleitung 47 ab, die mit der Förderpumpensauglei- tung 48 verbunden ist.For the temperature-dependent influencing of the fuel pressure when starting the internal combustion engine, the pressure valve 23 is arranged in the relief line 24, which leads away from the resetting space 21 of the pressure control valve 7. The relief line 24 leads to a control chamber 25 of the pressure valve 23. An actuating member 26 of a temperature-dependent element projects into the control chamber 25 27, for example an expansion element or a bimetal spring. The actuating member 26 engages a movable valve closing member 28 arranged in the pressure valve 23 and loaded by a return spring 29 arranged in a spring chamber 30. The valve closing member 28 is only moved by the actuating member 26 in the open position of the pressure valve 23 when the temperature-dependent working element 27 is activated, ie only at the minimum operating temperature of the internal combustion engine. A control line 32 branches off from the relief line 24 upstream of the connection to the pressure valve 23, which leads to a KSB control valve 8 and opens there via an inlet opening 33 in the peripheral wall of a KSB cylinder 35 of the KSB control valve 8. A connecting line 4 coming from the distributor 6 leads into a pressure chamber 39 bounded by the front end of the KSB cylinder 35 on the one hand. The pressure chamber 39 is on the other hand from an end side of an axially displaceable in the KSB cylinder 35 from one to another adjustable stop 37 supporting compression spring 36 limits the control piston 34. In the control piston 34 there is an annular groove 41, one boundary edge of which forms a control edge which controls the inlet opening 33. The annular groove 41 is connected by radial bores 42 to a blind bore 43 arranged axially in the control piston 34, which starts from the other end of the control piston 34, which is acted upon by the compression spring 36 and closes a spring chamber 40 in the KSB cylinder. From the spring chamber 40 there is a connecting line 45 to the spring chamber 30 of the pressure valve 23. From this connecting line 45 a drain line 47 branches off, which is connected to the feed pump suction line 48.
Der Gegenstand nach Figur 1 ergibt in Funktion eine Drehzahl/Druck¬ kennlinie, wie sie aus Figur 2 hervorgeht. Der Gegenstand nach Fi¬ gur 1 funktioniert folgendermaßen: Wird die Brennkraftmaschine unterhalb der Betriebstemperatur gestar¬ tet, so ist das Betätigungsglied 26 vom Ventilschließglied 28 abge¬ hoben und das Druckventil 23 geschlossen. Der Verstellkolben 11 be¬ findet sich bis zum Erreichen der Startdrehzahl in "Spätlage". In¬ folge des geschlossenen Drucksteuerventils 7 bei zugleich geschlos¬ senem Druckhalteventils 50 kann kein Kraftstoff abfließen, so daß sich im Saugraum 14 und Arbeitsraum 12 schnell ein Steuerdruck auf¬ baut, der eine Verschiebung des Verstellkolbens 11 in "Frühlage" be¬ wirkt. Durch das geschlossene Druckhalteventil 50 wird also schon bei geringer Drehzahl ein steiler Anstieg des Drucks im Saugraum 14 erreicht, wie er aus Figur 2 bis Punkt 62 erkennbar ist. In Punkt 62 öffnet das erfindungsgemäße Druckhalteventil 50 bei Erreichen eines eingestellten Offnungsdrucks. Der Kraftstoff kann nun - wenn der Kolben 16 des Drucksteuerventils 7 bei dem durch das geschlossene Druckventil 23 und die Drossel 22 bewirkten Druckausgleich die Ab¬ steueröffnung 19 aus konstruktiven Bedingungen und Vorgaben für den Verlauf der Steuerdruckänderung über der Drehzahl nicht vollständig schließen kann - über die Absteueröffnung 19, die Ablaufleitung 20 am Schließglied 51 des Druckhalteventils 50 vorbei in den Federraum 55 abfließen. Vom Federraum 55 fließt der Kraftstoff über die Ab¬ laufleitung 57 in die Förderpumpensaugleitung 48. Der Druck bleibt nach dem Öffnen des Druckhalteventils 50 zunächst nahezu konstant und steigt dann aber bei weiterer Drehzahlzunahme der Förderpumpe 1 entsprechend dem Kennlinienabschnitt 63 an. Hier wirkt sich die Drosselung des zum Teil geöffneten Absteuerschnitts 19 in V. m. der gestiegenen Förderrate der Förderpumpe 1 so aus, daß trotz Abfluß von geringer Kraftstoffmenge eine gewünschte Steigerung des Steuer¬ drucks erzielt wird, um die erforderliche Frühverstellung des Spritzbeginns bei kalter, noch nicht betriebswarmer Brennkraft¬ maschine zu erzielen. In diesem Kennlinienabschnitt 63 wird der Kraftstoffdruck einerseits durch den Absteuerquerschnitt an der Ab¬ steueröffnung 19 gesteuert und andererseits durch den Öffnungsdruck des Schließglieds 51, das gegen die Kraft der Schließfeder 52 öffnet. Die Schließkraft der Schließfeder 52, die sich an dem Kolben 53 ab¬ stützt, der mit dem in der Entlastungsleitung 24 herrschenden Druck beaufschlagt ist kann nun zusätzlich beeinflußt werden, derart, daß der Öffnungsdruck des Druckhalteventils 50 mit zunehmendem Druck im Rückstellraum 21 des Drucksteuerventils 7, welcher Druck zugleich der im Druckraum 18 des Druckhalteventils 7 und Arbeitsraum 12 der Spritzverstelleinrichtung 9 bei noch geschlossenem Druckventil 23 ist, erhöht wird. Kommt der Kolben 53 an seinen federseitigen An¬ schlag 87, so wird die Öffnungsdruckerhöhung beendet. Der Punkt 62 entspricht diesem Öffnungsdruck. Wird der Kolben 53 als Stützglied der Schließfeder 52 jedoch nicht vom Druck im Rückstellraum 21 bzw. in der Entlastungsleitung 24 stromaufwärts des Druckventils 23 bela¬ stet, so weist das Druckhalteventil einen durch den anderen Anschlag 88 des Kolbens 53 bestimmten Öffnungsdruck auf, der unveränderlich ist, aber auch einstellbar sein kann. An Punkt 63 beginnt das KSB-Regelventil 8 mit der Ringnut 41 am durch den Steuerdruck ver¬ schobenen Steuerkolben 34 die Eintrittsöffnung 33 zu öffnen entspre¬ chend einem am Anschlag 37 fein einstellbaren Öffnungsdruck.The object according to FIG. 1 results in a function of a speed / pressure characteristic as can be seen in FIG. 2. The object according to FIG. 1 works as follows: If the internal combustion engine is started below the operating temperature, the actuating member 26 is lifted off the valve closing member 28 and the pressure valve 23 is closed. The adjusting piston 11 is in the "late position" until the starting speed is reached. As a result of the closed pressure control valve 7 with the pressure holding valve 50 being closed at the same time, no fuel can flow away, so that a control pressure builds up quickly in the suction chamber 14 and the working chamber 12, which causes the adjusting piston 11 to be displaced into the "early position". Due to the closed pressure-maintaining valve 50, a steep increase in the pressure in the suction space 14 is achieved even at low speed, as can be seen from FIG. 2 to point 62. At point 62, the pressure holding valve 50 according to the invention opens when a set opening pressure is reached. The fuel can now - if the piston 16 of the pressure control valve 7 cannot completely close the control opening 19 from the structural conditions and specifications for the course of the control pressure change over the speed when the pressure is compensated by the closed pressure valve 23 and the throttle 22 - via the Discharge opening 19, the drain line 20 flow past the closing member 51 of the pressure control valve 50 into the spring chamber 55. The fuel flows from the spring chamber 55 via the drain line 57 into the feed pump suction line 48. The pressure initially remains almost constant after the pressure holding valve 50 is opened, but then increases as the feed pump 1 increases further in accordance with the characteristic curve section 63. Here, the throttling of the partially open control section 19 in V. m. the increased delivery rate of the delivery pump 1 in such a way that a desired increase in the control pressure is achieved in spite of the outflow of a small amount of fuel in order to achieve the required early adjustment of the start of injection when the internal combustion engine is cold and not yet warm. In this characteristic curve section 63, the fuel pressure is controlled on the one hand by the control cross section at the control opening 19 and on the other hand by the opening pressure of the closing element 51, which opens against the force of the closing spring 52. The closing force of the closing spring 52, which is supported on the piston 53, which is acted upon by the pressure prevailing in the relief line 24, can now also be influenced in such a way that the opening pressure of the pressure-maintaining valve 50 increases as the pressure in the return space 21 of the pressure control valve 7 increases Which pressure is simultaneously the pressure in the pressure chamber 18 of the pressure-maintaining valve 7 and the working chamber 12 of the spray adjustment device 9 when the pressure valve 23 is still closed. If the piston 53 comes to its spring-side stop 87, the increase in opening pressure is ended. The point 62 corresponds to this opening pressure. However, if the piston 53 as a supporting member of the closing spring 52 is not loaded by the pressure in the restoring space 21 or in the relief line 24 upstream of the pressure valve 23, the pressure-maintaining valve has an opening pressure which is determined by the other stop 88 of the piston 53 and which cannot be changed , but can also be adjustable. At point 63, the KSB control valve 8 with the annular groove 41 on the control piston 34 displaced by the control pressure 34 begins to open the inlet opening 33 in accordance with an opening pressure which can be finely adjusted at the stop 37.
Es kommt in der Folge zu einem flachen Anstieg des Steuerdrucks we¬ gen jetzt abfließender Kraftstoffmenge am KSB-Regelventil 8 gemäß Kennlinie 60. Im oberen Drehzahlbereich dient das KSB-Ventil 8 als druckabhängige Einrichtung, über die es durch die Absteuerkanten der Ringnut 41 und der Zylinderöffnung 33 zu einer zunehmenden Entla¬ stung kommt, durch die sich der Steuerdruckverlauf 60 dem Steuer- druckverlauf 64 bei betriebswarmer Brennkraftmaschine annähert.As a result, there is a flat increase in the control pressure due to the now flowing fuel quantity at the KSB control valve 8 in accordance with characteristic curve 60. In the upper speed range, the KSB valve 8 serves as a pressure-dependent device via which it passes through the control edges of the annular groove 41 and Cylinder opening 33 comes to an increasing relief, through which the control pressure curve 60 approaches the control pressure curve 64 when the internal combustion engine is at operating temperature.
Aus Kennlinie 65 ist ein p/n-Verhalten erkennbar, das sich ohne das erfindungsgemäße Druckhalteventil 50 einstellen würde. Bei niederer Drehzahl steigt der Druck über der Drehzahl nicht so steil wie mit dem erfindungsgemäßen Druckhalteventil 50 an. Bei höheren Drehzahlen haben die Kennlinien 60 und 65 nahezu, gesteuert durch das KSB-Re¬ gelventil 8, den gleichen Verlauf. Das gleiche Druck-/Drehzahlverhalten ergibt sich auch durch eine An¬ ordnung nach Figur 3. In Figur 3 ist eine alternative Anordnung des im übrigen gleichen Aufbaus dargestellt. Ein Druckhalteventil 50a weist einen als Schließglied arbeitenden Ventilkolben 66 auf, der mit einer in der Vorspannung einstellbaren Schließfeder 67 belastet ist und stirnseitig im Ventilgehäuse 70a einen Druckraum 89 be¬ grenzt, in den die Ablaufleitung 20 mündet und von dem durch die Stirnseite des Ventilkolbens gesteuert eine Verbindungsleitung 90 zur Förderpumpenansaugleitung 48 abführt. Die Schließfeder 67 liegt auf der dem Ventilkolben 66 gegenüberliegenden Seite an einer im Ventilzylinder 70a des Druckhalteventils 50 axial beweglichen Stütz- glied 69 an. Das Stützglied 69 ist durch eine elektrisch ansteuer¬ bare Vorrichtung 68 verstellbar. Die elektrische Vorrichtung 68 wird angesteuert durch Steuersignale, die durch eine drehzahlerfassende Meßeinrichtung oder durch einen Drucksensor gebildet werden. Ent¬ sprechend der Drehzahl bzw. dem Druck wird der Öffnungsdruck des Druckhalteventils 50a gesteuert, bei dessen Erreichen eine im Ven¬ tilzylinder 70a vorgesehene Absteueröffnung 71, die eine Verbindung zwischen Ablaufleitung 20 und Verbindungsleitung 90 herstellt, auf- oder zugesteuert wird. Neben der Beeinflussung des Steuerdruck¬ verlaufes, der in der Spritzbeginnverstelleinrichtung wirksam wird, entsprechend Kurve 62, 63, 60 von Figur 2 kann mit diesem Druckhal¬ teventil 50a auch bei betriebswarmer Brennkraftmaschine der Steuer¬ druck entsprechend Betriebsparameter der Brennkraftmaschine modifi¬ ziert werden.A characteristic curve p / n can be seen from characteristic curve 65, which would occur without the pressure holding valve 50 according to the invention. At low speed, the pressure does not rise as steeply as the speed with the pressure-maintaining valve 50 according to the invention. At higher speeds, the characteristic curves 60 and 65 have almost the same course, controlled by the KSB control valve 8. The same pressure / speed behavior also results from an arrangement according to FIG. 3. FIG. 3 shows an alternative arrangement of the rest of the same structure. A pressure-maintaining valve 50a has a valve piston 66, which acts as a closing element, is loaded with a closing spring 67 which can be set in the pretension and delimits a pressure chamber 89 in the valve housing 70a at the end, into which the discharge line 20 opens and which is controlled by the end face of the valve piston leads a connecting line 90 to the feed pump suction line 48. The closing spring 67 rests on the side opposite the valve piston 66 against a support member 69 which is axially movable in the valve cylinder 70a of the pressure-maintaining valve 50. The support member 69 can be adjusted by an electrically controllable device 68. The electrical device 68 is controlled by control signals which are formed by a speed-sensing measuring device or by a pressure sensor. The opening pressure of the pressure-maintaining valve 50a is controlled in accordance with the rotational speed or the pressure, upon reaching which a control opening 71 provided in the valve cylinder 70a, which establishes a connection between the discharge line 20 and the connecting line 90, is opened or closed. In addition to influencing the control pressure curve, which takes effect in the injection start adjustment device, in accordance with curve 62, 63, 60 of FIG. 2, this control pressure valve 50a can be used to modify the control pressure according to operating parameters of the internal combustion engine even when the internal combustion engine is warm.
Die Anordnung nach Figur 4 zeigt ein Druckhalteventil 50b mit einem Ventilzylinder 70b, von dessen einer Stirnseite 72 eine Verbindungs¬ leitung 73 zur Verbindungsleitung 3b, die von der Förderpumpe 1 kommt, führt. Im Ventilzylinder 70b gleitet axial verschiebbar, ein als Schließglied arbeitender Ventilkolben 74, der mit der Stirnseite 72 im Ventilyzlinder 70b einen Druckraum 89a begrenzt und in der Mantelfläche eine Ringnut 75 aufweist, deren eine Begrenzungskante (121) als Steuerkante dient. An der der Stirnseite 72 gegenüberlie¬ genden Seite des Ventilkolbens 74 liegt eine in ihrer Vorspanung än¬ derbare Schließfeder 76 an. Das andere Ende dieser Schließfeder 76 drückt an einen Kolben 77, der gleichfalls axial im Ventilzylinder 70b verschiebbar ist und zur zweiten Stirnseite 79 des Ventilzylin- ders 70b einen Druckraum 61 bildet. Von dieser zweiten Stirnseite 79 führt eine Verbindungsleitung 78 zu der Entlastungsleitung 24b, stromaufwärts des Druckventils 23. Am Umfang des Ventilzylinders 70b sind zwei Absteueröffnungen angeordnet, von denen eine die Absteuer¬ öffnung 81 ständig mit der Ringnut in Verbindung steht und zugleich mit der Forderpumpensaugleitung 48 verbunden ist. In die andere etwa Mitte des Ventilzylinders 70b angeordnete Absteueröffnung 80 tritt die Ablaufleitung 20 des Drucksteuerventils 7 ein. Diese Ab¬ steueröffnung 80 ist so angeordnet, daß die Ringnut 75 beim Start der Förderpumpe 1 keine Überdeckung mit der Absteueröffnung 80 hat, folglich noch kein Kraftstoff abfließen kann und kein Druck abgebaut wird. Durch die Förderpumpe 1 wird ein Druck erzeugt, der sich über die Verbindungsleitung 3b, in der Verbindungsleitung 73 und im Druckraum 18b des Drucksteuerventils 7 aufbaut und der analog zu den vorstehenden Ausführungsbeispielen bei geschlossenem Druckhalteven¬ til 50b zu einem steilen Steuerdruckanstieg und Frühverstellung des Spritzbeginns führt. Über die Verbindungsleitung 73 wird der Ventil¬ kolben 74 mit dem einzustellenden Steuerdruck beaufschlagt und würde sich axial verschieben, und die Ablaufleitung 20 über die Ringnut 75 aufsteuern, wenn nicht bei geschlossenem Druckventil 23 über die Drossel 22b der Steuerdruck in dem Rückstellraum 21b wäre, der über die Entlastungsleitung 24b und die Verbindungsleitung 78 auch in den Druckraum 61 gelangt. Dieser Steuerdruck liegt folglich auch am Kol¬ ben 77, der im Durchmesser größer als der Ventilkolben 74 ist, an und drückt über den Kolben 77 und die in der Vorspannung einstell¬ bare Schließfeder 76 auf den Ventilkolben 74. Auf diese Weise wird der Öffnungsdruck des Druckhalteventils 50b be¬ einflußt, und zwar in Abhängigkeit vom steilen Druckanstieg des zu steuernden Steuerdrucks. Der Öffnungsdruck kann auch hier von einem den Weg des Kolbens 77 in Richtung Schließfeder 76 begrenzenden An¬ schlag 87a begrenzt werden.The arrangement according to FIG. 4 shows a pressure holding valve 50b with a valve cylinder 70b, from one end face 72 of which a connecting line 73 leads to the connecting line 3b, which comes from the feed pump 1. A valve piston 74 slides axially displaceably in the valve cylinder 70b and acts as a closing member, which delimits a pressure chamber 89a with the end face 72 in the valve cylinder 70b and has an annular groove 75 in the lateral surface, one boundary edge of which (121) serves as the control edge. On the side of the valve piston 74 opposite the end face 72 there is a closing spring 76 which can be changed in its preload. The other end of this closing spring 76 presses on a piston 77, which is also axially displaceable in the valve cylinder 70b and forms a pressure chamber 61 to the second end face 79 of the valve cylinder 70b. From this second end face 79, a connecting line 78 leads to the relief line 24b, upstream of the pressure valve 23. On the circumference of the valve cylinder 70b, two control openings are arranged, one of which the control opening 81 is constantly connected to the annular groove and at the same time to the delivery pump suction line 48 connected is. The discharge line 20 of the pressure control valve 7 enters the other control opening 80, which is arranged approximately in the middle of the valve cylinder 70b. This Ab¬ control opening 80 is arranged so that the annular groove 75 at the start of the feed pump 1 has no overlap with the control opening 80, consequently no fuel can drain and no pressure is released. A pressure is generated by the feed pump 1, which builds up via the connecting line 3b, in the connecting line 73 and in the pressure chamber 18b of the pressure control valve 7 and which, analogously to the above exemplary embodiments, leads to a steep rise in control pressure and early adjustment of the start of injection when the pressure holding valve 50b is closed . Via the connecting line 73, the valve piston 74 is acted upon by the control pressure to be set and would move axially, and the drain line 20 would open up via the annular groove 75 if the control pressure in the reset space 21b were not via the throttle 22b when the pressure valve 23 was closed also reaches the pressure chamber 61 via the relief line 24b and the connecting line 78. This control pressure is therefore also present on the piston 77, which is larger in diameter than the valve piston 74, and presses on the valve piston 74 via the piston 77 and the closing spring 76, which can be set in the prestress. In this way, the opening pressure of the pressure control valve 50b is influenced, depending on the steep pressure rise of the control pressure to be controlled. Here too, the opening pressure can be limited by a stop 87a which limits the path of the piston 77 in the direction of the closing spring 76.
Figur 5 zeigt einen als Schließglied arbeitenden Ventilkolben 86, der dem Ventilkolben 74 der Figur 4 entspricht. In der Anordnung nach Figur 5 ist der druckabhängig steuerbare Kolben 77 von Figur 4 durch eine elektrisch steuerbare Vorrichtung 68a ersetzt, die der der Vorrichtung 68 aus Figur 3 entspricht. Bei dieser Anordnung nach Figur 5 wird folglich der Druck mittels eines Drucksensors gemessen, der ein Steuersignal für die elektrisch ansteuerbare Vorrichtung ergibt. FIG. 5 shows a valve piston 86 operating as a closing member, which corresponds to the valve piston 74 of FIG. 4. In the arrangement according to FIG. 5, the pressure-controllable piston 77 from FIG. 4 is replaced by an electrically controllable device 68a, which corresponds to that of the device 68 from FIG. In this arrangement according to FIG. 5, the pressure is consequently measured by means of a pressure sensor, which gives a control signal for the electrically controllable device.

Claims

Ansprüche Expectations
1. Kraftstoffeinspritzpumpe für Brennkraftmaschinen, insbesondere Verteilereinspritzpumpen mit einer synchron zur Kraftstoffeinspritz¬ pumpe angetriebenen Förderpumpe, die einen Steuerdruck erzeugt und von der eine Verbindungsleitung zu einem Druckraum eines Drucksteu¬ erventils und zu einem Druckraum eines Spritzverstellers führt, wo¬ bei im Drucksteuerventil (7) zwischen Druckraum (18) und einem Rück- stellraum (21), welche beide über eine konstante Drossel (22) mit¬ einander verbunden sind, eine durch den Druck im Druckraum (18) ge¬ gen eine Rückstellfeder (17) bewegbare und einen Absteuerguerschnitt einer Absteueröffnung (19) zu einer Ablaufleitung (20) steuernde be¬ wegliche Wand (16) vorgesehen ist und vom Rückstellraum (21) eine ein steuerbares Druckventil (23) enthaltende Entlastungsleitung (24) abführt, dadurch gekennzeichnet, daß in die Ablaufleitung (20) ein steuerbares Druckhalteventil (50) eingebaut ist.1. Fuel injection pump for internal combustion engines, in particular distributor injection pumps with a feed pump driven synchronously with the fuel injection pump, which generates a control pressure and from which a connecting line leads to a pressure chamber of a pressure control valve and to a pressure chamber of an injection adjuster, the pressure control valve (7) between the pressure chamber (18) and a restoring space (21), both of which are connected to each other via a constant throttle (22), one that can be moved by the pressure in the pressure chamber (18) against a restoring spring (17) and a control valve section A discharge wall (16) controlling a discharge opening (19) to a discharge line (20) is provided and a relief line (24) containing a controllable pressure valve (23) leads away from the resetting space (21), characterized in that in the discharge line (20 ) a controllable pressure maintaining valve (50) is installed.
2. Kraftstoffeinspritzpumpe nach Anspruch 1, dadurch gekennzeichnet, daß das Druckhalteventil (50) ein den Durchfluß der Ablaufleitung (20) steuerndes Schließglied (51) aufweist, das von einer Schlie߬ feder (52) mit steuerbarer Spannung beaufschlagt wird.2. A fuel injection pump according to claim 1, characterized in that the pressure-maintaining valve (50) has a closing member (51) which controls the flow of the outlet line (20) and which is acted upon by a closing spring (52) with controllable voltage.
3. Kraftstoffeinspritzpumpe nach Anspruch 2, dadurch gekennzeichnet, daß sich die Schließfeder (52) an einem in einem Zylinder des Druck¬ halteventils (50) angeordneten axial beweglichen Stützglied (53) ab¬ stützt, das (53) von dem im Rückstellraum (21) herrschenden Druck beaufschlagt und gegen die Schließfeder verschiebbar ist. 3. Fuel injection pump according to claim 2, characterized in that the closing spring (52) on an in a cylinder of the Druck¬ holding valve (50) arranged axially movable support member (53) ab¬, which (53) from that in the reset space (21st ) prevailing pressure and can be moved against the closing spring.
4. Kraftstoffeinspritzpumpe nach Anspruch 2 oder 3, dadurch gekenn¬ zeichnet, daß sich die Schließfeder (67) an einem in Abhängigkeit von Betriebsparametern der Brennkraftmaschine elektrisch verstell¬ baren Stützglied (69) abstützt.4. Fuel injection pump according to claim 2 or 3, characterized gekenn¬ characterized in that the closing spring (67) is supported on a depending on the operating parameters of the engine electrically adjustable support member (69).
5. Kraftstoffeinspritzpumpe nach Anspruch 3 oder 4, dadurch gekenn¬ zeichnet, daß der Hub des Stützglieds (69) durch Anschläge begrenzt ist.5. Fuel injection pump according to claim 3 or 4, characterized gekenn¬ characterized in that the stroke of the support member (69) is limited by stops.
6. Kraftstoffeinspritzpumpe nach Anspruch 4, dadurch gekennzeichnet, daß das Stützglied (69) in Abhängigkeit von der Temperatur verstellbar ist.6. Fuel injection pump according to claim 4, characterized in that the support member (69) is adjustable depending on the temperature.
7. Kraftstoffeinspritzpumpe nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß das Schließglied (51) das Druckhalteven¬ tils (50) ein vom im Druckraum (18) des Drucksteuerventil (7) herr¬ schenden Förderdruck gegen die Schließfeder (52) in einem Ventil¬ zylinder (70b) des Drucksteuerventils (7) verschiebbarer Kolben¬ schieber (74) ist, der mit einer Steuerkante den Durchfluß der Ab¬ laufleitung (20) steuert (Figur 4).7. Fuel injection pump according to one of the preceding claims, characterized in that the closing member (51) the Druckhalteven¬ valve (50) from the pressure chamber (18) of the pressure control valve (7) herr¬ prevailing delivery pressure against the closing spring (52) in a valve ¬ cylinder (70b) of the pressure control valve (7) is displaceable piston slide (74) which controls the flow of the drain line (20) with a control edge (FIG. 4).
8. Kraftstoffeinspritzpumpe nach Anspruch 7, dadurch gekennzeichnet, daß der Kolbenschieber (74) in seiner Mantelfläche eine Ringnut (75) aufweist, deren eine Begrenzungskante (121) die Steuerkante ist, mit der die Einmündung in oder der Austritt aus dem Ventilzylinder (70b), der den Ventilzylinder (70b) durchlaufenden Ablaufleitung (20) gesteuert wird (Figur 4).8. Fuel injection pump according to claim 7, characterized in that the piston slide (74) has in its outer surface an annular groove (75), one boundary edge (121) of which is the control edge with which the outlet into or the outlet from the valve cylinder (70b) , the drain line (20) passing through the valve cylinder (70b) is controlled (FIG. 4).
9. Kraftstoffeinspritzpumpe nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß zur Steuerung des Druckventils (23) eine Steuereinrichtung vorgesehen ist, durch die bei betriebswarmer Brennkraftmaschine oder zusätzlich bei Erreichen einer bestimmten Drehzahl der Rückstellraum unabhängig vom Erreichen des Schlie߬ drucks des Druckventils entlastbar ist. 9. Fuel injection pump according to one of the preceding claims, characterized in that a control device is provided for controlling the pressure valve (23) through which the return space can be relieved independently of reaching the closing pressure of the pressure valve when the internal combustion engine is warm or when a certain speed is reached .
10. Kraftstoffeinspritzumpe nach Anspruch 9 mit einem Druckventil (23), das ein mit einem Ventilsitz gepaartes von einer Feder bela¬ stetes Schließglied (28) aufweist, dadurch gekennzeichnet, daß die Steuereinrichtung ein temperaturabhängig betätigbares Stellorgan (27) hat, durch das das Schließglied (28) von seinem Ventilsitz bei Erreichen einer bestimmten Betriebstemperatur der Brennkraftmaschine abgehoben wird. 10. Fuel injection pump according to claim 9 with a pressure valve (23) which has a paired with a valve seat loaded by a spring closing member (28), characterized in that the control device has a temperature-dependent actuating member (27) through which the closing member (28) is lifted from its valve seat when a certain operating temperature of the internal combustion engine is reached.
EP89906727A 1988-07-01 1989-06-16 Fuel injection pump for internal combustion engines Expired - Lifetime EP0386175B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3822257 1988-07-01
DE3822257A DE3822257A1 (en) 1988-07-01 1988-07-01 FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES

Publications (2)

Publication Number Publication Date
EP0386175A1 true EP0386175A1 (en) 1990-09-12
EP0386175B1 EP0386175B1 (en) 1993-05-12

Family

ID=6357732

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89906727A Expired - Lifetime EP0386175B1 (en) 1988-07-01 1989-06-16 Fuel injection pump for internal combustion engines

Country Status (6)

Country Link
US (1) US5033441A (en)
EP (1) EP0386175B1 (en)
JP (1) JP2974705B2 (en)
KR (1) KR900702190A (en)
DE (2) DE3822257A1 (en)
WO (1) WO1990000224A1 (en)

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DE3912624A1 (en) * 1989-04-18 1990-10-25 Bosch Gmbh Robert FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES
US5263457A (en) * 1989-12-06 1993-11-23 Robert Bosch Gmbh Fuel injection pump for internal combustion engines
DE3943246A1 (en) * 1989-12-29 1991-07-04 Bosch Gmbh Robert FUEL INJECTION PUMP
DE4311672A1 (en) * 1993-04-08 1994-10-13 Bosch Gmbh Robert Fuel injection pump
US5558068A (en) * 1994-05-31 1996-09-24 Zexel Corporation Solenoid valve unit for fuel injection apparatus
DE19549046A1 (en) * 1995-12-28 1997-07-03 Bosch Gmbh Robert Fuel injection pump for internal combustion engines
DE10156989A1 (en) * 2001-11-21 2003-06-05 Bosch Gmbh Robert Mechanical distributor injection pump with cold start acceleration

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DE2925418A1 (en) * 1979-06-23 1981-01-29 Bosch Gmbh Robert FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES
DE2931944A1 (en) * 1979-08-07 1981-03-26 Robert Bosch Gmbh, 70469 Stuttgart FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES
DE2931938A1 (en) * 1979-08-07 1981-02-26 Bosch Gmbh Robert FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES
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Also Published As

Publication number Publication date
WO1990000224A1 (en) 1990-01-11
US5033441A (en) 1991-07-23
DE58904357D1 (en) 1993-06-17
JP2974705B2 (en) 1999-11-10
DE3822257A1 (en) 1990-01-04
EP0386175B1 (en) 1993-05-12
KR900702190A (en) 1990-12-06
JPH03500325A (en) 1991-01-24

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