EP0422130A1 - Fuel injection pump for internal combustion engines. - Google Patents

Fuel injection pump for internal combustion engines.

Info

Publication number
EP0422130A1
EP0422130A1 EP19890909154 EP89909154A EP0422130A1 EP 0422130 A1 EP0422130 A1 EP 0422130A1 EP 19890909154 EP19890909154 EP 19890909154 EP 89909154 A EP89909154 A EP 89909154A EP 0422130 A1 EP0422130 A1 EP 0422130A1
Authority
EP
European Patent Office
Prior art keywords
damping
fuel injection
pump piston
pump
piston
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP19890909154
Other languages
German (de)
French (fr)
Other versions
EP0422130B1 (en
Inventor
Roland Kupzik
Eberhard Schunck
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 EP0422130A1 publication Critical patent/EP0422130A1/en
Application granted granted Critical
Publication of EP0422130B1 publication Critical patent/EP0422130B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • 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
    • F02M41/121—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 with piston arranged axially to driving shaft
    • 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
    • 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

Definitions

  • the invention relates to a fuel injection pump according to the preamble of the main claim. It is already known from DE-OS 3144 277 a fuel injection pump, which has a hydraulic interception device to increase the output by increasing the conveying speed of the pump piston, in order to slow down the oscillating pump piston, by the screw springs which the pump piston has in the system should hold the front cam, supplementary restoring forces that are no longer realizable.
  • the known hydraulic interception device requires a throttle groove on the pump piston in order to limit the outflow of the fuel from a damping space.
  • the attachment of the throttle groove on the pump piston requires additional and also cost-intensive operations, since the throttle groove usually has to be created by eroding.
  • the braking effect acts on the major part of the pump piston movement, so that higher driving forces than necessary are necessary.
  • the arrangement according to the invention with the characterizing features of the main claim has the advantage that a further Increase in the speed of the pump piston and thus an increase in performance of the fuel injection pump is possible, although the hydraulic stop has no additional relief groove and the braking effect occurs only partially in the area of the upper turning point of the pump piston.
  • Advantageous further developments and improvements of the hydraulic interception device specified in the main claim are possible through the measures listed in the subclaims.
  • FIG. 1 shows a simplified side view of a fuel injection pump, partly in section
  • FIG. 2 shows a partial section in a schematic representation through a cylinder liner of the fuel injection pump with the pump piston guided in the cylinder liner.
  • FIG. 1 a partial section is shown in a simplified representation in FIG. 1 through a fuel injection pump of the distributor type, in which a drive shaft 2 is mounted in a housing 1 and to which a lifting disk 3 arranged transversely to the drive shaft 2 is coupled, which correspondingly the number of cylinders of the internal combustion engine to be supplied is provided with end cams 4.
  • the running surface of the lifting disc 3 rests on rollers 5 which are held in a fixed roller ring 6.
  • a pump piston 9 sliding in a bore 7 of a cylinder liner 8 has a collar 10 on its drive-side end which projects into a fuel-filled suction chamber 26 and is connected to the lifting disk 3 in a rotationally fixed manner.
  • a control slide 11 which surrounds the pump piston 9, slides on the pump piston section on the drive side, in which a transverse bore 12 controlled by the control slide 11 is arranged to control partial quantities of the fuel delivered, said transverse bore 12 being connected to the front side of the pump piston bens 9 leading longitudinal bore 13 is connected and there opens into a pump work chamber 14.
  • Adjustment means 15 act on the control slide 11, the position of which is controlled in a known manner by a speed controller.
  • On the collar 10 of the pump piston 9 there is a slide rail 16 against which a yoke 18 loaded by at least one return spring 17 presses. To simplify matters, only one return spring 17 is shown, but preferably two or more return springs 17 are provided.
  • a guide pin 19 extends coaxially with the return spring 17, which on the one hand fastens in size 1 and on the other hand engages through a fit 20 in the yoke 18, so that the yoke 18 is secured against rotation.
  • the return spring 17 is supported at one end via a spring plate 21 on the housing 1 and at the other end on the yoke 18, as a result of which the lifting disk 3 is pressed against the rollers 5.
  • FIG. 2 shows a partial view of a fuel injection pump according to FIG. 1 modified according to the invention.
  • the pump piston 9 is of stepped design, where in which the smaller diameter part of the pump piston 9 is slidably guided in the bore 7 of the cylinder liner 8.
  • the cylinder liner 8 has a damping bore 24, which is designed as a damping chamber and extends from the suction chamber and faces the larger diameter part of the pump piston 9 and whose axis coincides with the axis of the pump piston 9.
  • the end-face annular surface between the large diameter and the small diameter of the pump piston 9 forms a damping surface 23.
  • the pump piston 9 assumes a lowermost movement position UT and an uppermost movement position OT within one movement cycle.
  • the pump piston 9 in contact with the end cam 4 with the damping surface 23 in TDC approaches the front boundary of the damping space 22 to a small extent, which is less than 1 mm.
  • the mass force of the Pump piston 9, the contact pressure of the return spring 17, the positive connection between the pump piston 9 and the front cam 4 is lost.
  • the damping surface 23 of the pump piston 9 can thus enter the damping space 23, as a result of which it forms an annular gap 25 between the outer surface of the larger diameter part of the pump piston 9 and the damping bore 24 that limits the damping space, which then forms the only connection from the damping chamber 22 to a suction chamber 26 of the fuel injection pump leading as a relief chamber.
  • the throttled evasive capacity of the fuel enclosed in the damping chamber 22 creates a hydraulic spring, the restoring force of which counteracts the movement of the pump piston 9 and, after the delivery stroke movement of the pump piston 9, supports the positioning force of the return spring 17 in the same direction.
  • other or additional throttle connections from the damping space 22 to the suction space 26 or other storage spaces can also be provided in order to reduce the maximum pressure.
  • the functional sequence described results in the following sequence of effects.
  • the front cam 4 has its outer contour in TDC the small most radius with the result that the positive-locking pump piston 9 experiences the greatest delays here.
  • a strongly accelerated pump piston 9 lifts off the front cam 4 before TDC, but is quickly limited and quickly returned to the front cam 4 by the damped braking shortly after TDC in its free flight, as a result of which the radio ability of the cam drive is increased.
  • the transverse forces caused by the delivery stroke pressure as a result of the torsion of the drive shaft 2 and the displacements of the cam drive can cause wear points which lead to the pump piston 9 jamming.
  • the previously described positive locking separation between pump piston 9 and front cam 4 avoids the influence of transverse forces on the pump piston before TDC; this largely avoids the bearing wear of the pump piston 9.
  • the exemplary embodiment described thus allows, by intercepting the oscillating pump piston 9 by means of the additional hydraulic force in the manner according to the invention with lower susceptibility to wear, higher delivery speeds or drive speeds of the fuel injection pump or higher stroke numbers of the pump piston per revolution with the same delivery rate, which increases the performance of the fuel injection pump has the consequence.

Landscapes

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

Abstract

Dispositif de ralentissement du piston (9) d'une pompe d'injection de carburant pour moteur à combustion interne. Ce dispositif comporte un piston de pompe (9) qui glisse et tourne à l'intérieur d'un alésage (7) où il est logé. Ce piston (9) est en escalier et, lorsqu'il est soumis à une forte accélération et que la liaison de forme avec l'entraînement à came ne se fait plus, sa partie la plus large peut, juste après qu'il a atteint le sommet de sa trajectoire, pénétrer dans un espace d'amortissement fixe (22) en y laissant un interstice annulaire (25). Du fait que le carburant contenu dans l'espace d'amortissement (22) ne peut s'échapper que lentement, on obtient un effet de ressort hydraulique dont la force de rappel s'oppose au mouvement du piston (9). De ce fait, le piston (9) est retenu même en cas de vitesses de déplacement élevées, ce qui accroît le rendement de la pompe d'injection de carburant.Device for slowing down the piston (9) of a fuel injection pump for an internal combustion engine. This device comprises a pump piston (9) which slides and rotates inside a bore (7) where it is housed. This piston (9) is in staircase and, when it is subjected to a strong acceleration and that the form connection with the cam drive is no longer made, its widest part can, just after it has reached the top of its trajectory, enter a fixed damping space (22) leaving an annular gap (25) there. Because the fuel contained in the damping space (22) can escape only slowly, a hydraulic spring effect is obtained, the restoring force of which is opposed to the movement of the piston (9). Therefore, the piston (9) is retained even at high travel speeds, which increases the efficiency of the fuel injection pump.

Description

Kraftstoffeinspritzpumpe für Brennkraftmasehinen Fuel injection pump for internal combustion engines
Stand der TechnikState of the art
Die Erfindung geht aus von einer Kraftstoffeinspritzpumpe nach der Gattung des Hauptanspruchs. Es ist schon durch die DE-OS 3144 277 eine Kraftstoffeinspritzpumpe bekannt, die zur Leistungssteigerung über die Erhöhung der Fördergeschwindigkeit des Pumpenkolbens eine hydraulische Abfangvorrichtung aufweist, um die zur Verzögerung des oszillierenden Pumpenkolbens erforderlichen, von den Schraubenfe¬ dern, die den Pumpenkolben in Anlage mit dem Stirnnocken halten sol¬ len, nicht mehr realisierbaren Rückstellkräfte zu ergänzen. Die be¬ kannte hydraulische Abfangvorrichtung benötigt eine Drosselnut am Pumpenkolben, um die Abströmung des Kraftstoffes aus einem Dämp¬ fungsraum zu begrenzen. Das Anbringen der Drosselnut am Pumpenkolben erfordert zusätzliche und zudem kostenintensive Arbeitsvorgänge, da die Drosselnut üblicherweise durch Erodieren erstellt werden muß. Des weiteren beaufschlagt die Bremswirkung den überwiegenden Teil der Pumpenkolbenbewegung, so daß höhere Antriebskräfte als erforder¬ lich notwendig werden.The invention relates to a fuel injection pump according to the preamble of the main claim. It is already known from DE-OS 3144 277 a fuel injection pump, which has a hydraulic interception device to increase the output by increasing the conveying speed of the pump piston, in order to slow down the oscillating pump piston, by the screw springs which the pump piston has in the system should hold the front cam, supplementary restoring forces that are no longer realizable. The known hydraulic interception device requires a throttle groove on the pump piston in order to limit the outflow of the fuel from a damping space. The attachment of the throttle groove on the pump piston requires additional and also cost-intensive operations, since the throttle groove usually has to be created by eroding. Furthermore, the braking effect acts on the major part of the pump piston movement, so that higher driving forces than necessary are necessary.
Vorteile der ErfindungAdvantages of the invention
Die erfindungsgemäße Anordnung mit den kennzeichnenden Merkmalen des Hauptanspruchs hat demgegenüber den Vorteil, daß eine weitere Er- höhung der Geschwindigkeit des Pumpenkolbens und damit eine Lei¬ stungssteigerung der Kraftstoffeinspritzpumpe möglich ist, obwohl der hydraulische Anschlag keine zusätzliche Entlastungsnut aufweist und die Bremswirkung nur partiell im Bereich des oberen Umkehrpunk¬ tes des Pumpenkolbens erfolgt. Durch die in den Unteransprüchen auf¬ geführten Maßnahmen sind vorteilhafte Weiterbildungen und Verbesse¬ rungen der im Hauptanspruch angegebenen hydraulischen Abfangvorrich¬ tung möglich. In vorteilhafter Weise ist es die Bremswirkung gemäß Anspruch 4, erst im Falle eines tatsächlichen, bei hoher Betriebs¬ drehzahl erfolgenden Abhebens des Pumpenkolbens oder die diesen an¬ treibenden Hockenscheibe vom Rollenring eintreten zu lassen. Beson¬ ders vorteilhaft ist dabei, daß der Förderhubdruck und der Brems¬ druck auf dem Pumpenkolben zeitlich hintereinander ablaufen und so Querkräfte, die das Blockieren des Pumpenkolbens hervorrufen können, vermieden werden.The arrangement according to the invention with the characterizing features of the main claim has the advantage that a further Increase in the speed of the pump piston and thus an increase in performance of the fuel injection pump is possible, although the hydraulic stop has no additional relief groove and the braking effect occurs only partially in the area of the upper turning point of the pump piston. Advantageous further developments and improvements of the hydraulic interception device specified in the main claim are possible through the measures listed in the subclaims. Advantageously, it is the braking effect according to claim 4 that the pump piston can only enter when the pump piston is actually lifted off at a high operating speed or the cam disk driving it is in motion. It is particularly advantageous that the delivery stroke pressure and the brake pressure on the pump piston run in succession, thus avoiding transverse forces which can cause the pump piston to lock.
Zeichnungdrawing
Die Erfindung ist in der Zeichnung anhand zweier Figuren dargestellt und in der nachfolgenden. Beschreibung näher erläutert. Es zeigt Figur 1 eine vereinfachte Seitenansicht einer Kraftstoffeinspritz¬ pumpe, teilweise geschnitten und Figur 2 in schematischer Darstel¬ lung einen Teilschnitt durch eine Zylinderbüchse der Kraftstoffein¬ spritzpumpe mit dem in der Zylinderbüchse geführten Pumpenkolben.The invention is shown in the drawing using two figures and in the following. Description explained in more detail. FIG. 1 shows a simplified side view of a fuel injection pump, partly in section, and FIG. 2 shows a partial section in a schematic representation through a cylinder liner of the fuel injection pump with the pump piston guided in the cylinder liner.
Beschreibung der AusführungsbeispieleDescription of the embodiments
In der Zeichnung ist in Figur 1 in vereinfachter Darstellung ein Teilschnitt .durch eine Kraftstoffeinspritzpumpe der Verteilerbauart dargestellt, bei der in einem Gehäuse 1 eine Antriebswelle 2 gela¬ gert und an welche eine quer zur Antriebswelle 2 angeordnete Hub¬ scheibe 3 gekoppelt ist, die entsprechend der zu versorgenden Zahl der Zylinder der Brennkraftmaschine mit Stirnnocken 4 versehen ist. Die Lauffläche der Hubscheibe 3 liegt auf Rollen 5 auf, die in einem feststehenden Rollenring 6 gehalten sind. Ein in einer Bohrung 7 einer Zylinderbüchse 8 gleitender Pumpenkolben 9 hat an seinem an- triebsseitigen, in einen kraftstoffgefüllten Saugraum 26 ragenden Ende einen Bund 10, der mit der Hubscheibe 3 drehfest verbunden ist. Zur Steuerung der Kraftstoffeinspritzmenge gleitet ein dem Pumpen¬ kolben 9 umgreifender Steuerschieber 11 auf dem aatriebsseitigen Pumpenkolbenabschnitt, in dem zum Absteuern von Teilmengen des ge¬ förderten Kraftstoffs eine vom Steuerschieber 11 gesteuerte Querboh¬ rung 12 angeordnet ist, die mit einer zur Stirnseite des Pumpenkol¬ bens 9 führenden Längsbohrung 13 verbunden ist und dort in einen Pumpenarbeitsraum 14 mündet. An dem Steuerschieber 11 greifen Ver¬ stellmittel 15 an, deren Stellung in bekannter Weise von einem Dreh¬ zahlregler gesteuert wird. An dem Bund 10 des Pumpenkolbens 9 liegt eine Gleitschiene 16 an, gegen die ein von wenigstens einer Rückhol¬ feder 17 belastetes Joch 18 drückt. Vereinfachend ist nur eine Rück¬ holfeder 17 dargestellt, vorzugsweise sind jedoch zwei oder mehrere Rückholfedern 17 vorgesehen. Gleichachsig zur Rückholfeder 17 er¬ streckt sich ein Führungsstift 19, der einerseits in Größe 1 befe¬ stigt und andererseits durch eine Paßform 20 im Joch 18 hindurch¬ greift, so daß das Joch 18 gegen Verdrehen gesichert ist. Die Rück¬ holfeder 17 stützt sich mit ihrem einen Ende über einen Federteller 21 am Gehäuse 1 und mit dem anderen Ende am Joch 18 ab, wodurch die Hubscheibe 3 gegen die Rollen 5 gedrückt wird. Beim Drehen der An¬ triebswelle 2 wird der Pumpenkolben 9 in gleicher Weise mitgedreht und zusätzlich hin und her bewegt, wobei der Förderhub durch die Stirnnocken 4 der Hubscheibe 13 entgegen der Wirkung der Rückhol¬ feder 17 und der Saughub durch die gespeicherte Kraft der Rückhol¬ feder 17 bewirkt wird.In the drawing, a partial section is shown in a simplified representation in FIG. 1 through a fuel injection pump of the distributor type, in which a drive shaft 2 is mounted in a housing 1 and to which a lifting disk 3 arranged transversely to the drive shaft 2 is coupled, which correspondingly the number of cylinders of the internal combustion engine to be supplied is provided with end cams 4. The running surface of the lifting disc 3 rests on rollers 5 which are held in a fixed roller ring 6. A pump piston 9 sliding in a bore 7 of a cylinder liner 8 has a collar 10 on its drive-side end which projects into a fuel-filled suction chamber 26 and is connected to the lifting disk 3 in a rotationally fixed manner. In order to control the fuel injection quantity, a control slide 11, which surrounds the pump piston 9, slides on the pump piston section on the drive side, in which a transverse bore 12 controlled by the control slide 11 is arranged to control partial quantities of the fuel delivered, said transverse bore 12 being connected to the front side of the pump piston bens 9 leading longitudinal bore 13 is connected and there opens into a pump work chamber 14. Adjustment means 15 act on the control slide 11, the position of which is controlled in a known manner by a speed controller. On the collar 10 of the pump piston 9 there is a slide rail 16 against which a yoke 18 loaded by at least one return spring 17 presses. To simplify matters, only one return spring 17 is shown, but preferably two or more return springs 17 are provided. A guide pin 19 extends coaxially with the return spring 17, which on the one hand fastens in size 1 and on the other hand engages through a fit 20 in the yoke 18, so that the yoke 18 is secured against rotation. The return spring 17 is supported at one end via a spring plate 21 on the housing 1 and at the other end on the yoke 18, as a result of which the lifting disk 3 is pressed against the rollers 5. When the drive shaft 2 is rotated, the pump piston 9 is rotated in the same way and additionally moved back and forth, the conveying stroke by the end cams 4 of the lifting disk 13 counter to the action of the return spring 17 and the suction stroke by the stored force of the return spring 17 is effected.
Das in Figur 2 dargestellte Ausführungsbeispiel zeigt eine Teilan¬ sicht einer erfindungsgemäß modifizierten Kraftstoffeinspritzpumpe nach Figur 1. Dabei ist der Pumpenkolben 9 gestuft ausgeführt, wo- bei der im Durchmesser kleinere Teil des Pumpenkolbens 9 in der Boh¬ rung 7 der Zylinderbüchse 8 gleitend geführt ist. Die Zylinderbüchse 8 weist eine als Dämpfungsraum ausgebildete, vom Saugraum ausgehende Dämpfungsbohrung 24 auf, die dem im Durchmesser größeren Teil des Pumpenkolbens 9 zugewandt ist und deren Achse mit der Achse des Pum¬ penkolbens 9 zusammenfällt. Die stirnseitige Ringfläche zwischen dem großen Durchmesser und dem kleinen Durchmesser des Pumpenkolbens 9 bildet eine Dämpfungsfläche 23. Der Pumpenkolben 9 nimmt innerhalb eines BewegungsZyklus eine unterste Bewegungslage UT und eine ober¬ ste Bewegungslage OT ein. Bei einer Förderhubbewegung nähert sich der in Anlage mit dem Stirnnocken 4 befindliche Pumpenkolben 9 mit der Dänpfungsfläche 23 in OT bis auf ein geringes Maß, das geringer als 1 mm ist, der vorderen Begrenzung des Dämpfungsraums 22. Über¬ steigt bei hoher Geschwindigkeit die Massenkraft des Pumpenkolbens 9 die Anpreßkraft der Rückholfeder 17, so geht der Formschluß zwischen Pumpenkolben 9 und Stirnnocken 4 verloren. Kurz nach OT kann dadurch die Dämpfungsfläche 23 des Pumpenkolbens 9 in den Dämpfungsraum 23 eintreten, wodurch sie zwischen der Mantelfläche des im Durchmesser größeren Teils des Pumpenkolbens 9 und der dem Dämpfungsräum begren¬ zenden Dämpfungsbohrung 24 ein ringförmiger Spalt 25 bildet, der dann die einzige Verbindung von dem Dämpfungsraum 22 zu einem als Ξntlastungsräum führenden Saugraum 26 der Kraftstoffeinspritzpumpe darstellt. Durch das gedrosselte Ausweichvermögen des im Dämpfungs¬ raum 22 eingeschlossenen Kraftstoffs entsteht eine hydraulische Feder, deren Rückstellkraft der Bewegung des Pumpenkolbens 9 entge¬ gengerichtet ist und nach der Förderhubbewegung des Pumpenkolbens 9 die Stellkraft der Rückholfeder 17 gleichgerichtet unterstützt. Zur Modifikation der Rückführkraft bzw. Dämpfung können auch andere oder zusätzliche Drosselverbiήdungen des Dämpfungsraumes 22 zum Saugraum 26 oder anderen Speicherräumen vorgesehen werden, um den Maximal¬ druck zu reduzieren.The exemplary embodiment shown in FIG. 2 shows a partial view of a fuel injection pump according to FIG. 1 modified according to the invention. The pump piston 9 is of stepped design, where in which the smaller diameter part of the pump piston 9 is slidably guided in the bore 7 of the cylinder liner 8. The cylinder liner 8 has a damping bore 24, which is designed as a damping chamber and extends from the suction chamber and faces the larger diameter part of the pump piston 9 and whose axis coincides with the axis of the pump piston 9. The end-face annular surface between the large diameter and the small diameter of the pump piston 9 forms a damping surface 23. The pump piston 9 assumes a lowermost movement position UT and an uppermost movement position OT within one movement cycle. In the event of a conveying stroke movement, the pump piston 9 in contact with the end cam 4 with the damping surface 23 in TDC approaches the front boundary of the damping space 22 to a small extent, which is less than 1 mm. The mass force of the Pump piston 9, the contact pressure of the return spring 17, the positive connection between the pump piston 9 and the front cam 4 is lost. Shortly after TDC, the damping surface 23 of the pump piston 9 can thus enter the damping space 23, as a result of which it forms an annular gap 25 between the outer surface of the larger diameter part of the pump piston 9 and the damping bore 24 that limits the damping space, which then forms the only connection from the damping chamber 22 to a suction chamber 26 of the fuel injection pump leading as a relief chamber. The throttled evasive capacity of the fuel enclosed in the damping chamber 22 creates a hydraulic spring, the restoring force of which counteracts the movement of the pump piston 9 and, after the delivery stroke movement of the pump piston 9, supports the positioning force of the return spring 17 in the same direction. To modify the return force or damping, other or additional throttle connections from the damping space 22 to the suction space 26 or other storage spaces can also be provided in order to reduce the maximum pressure.
Der beschriebene Funktionsablauf ergibt den nachfolgenden Wirkungs¬ ablauf. Der Stirnnocken 4 weist seiner Außenkontur in OT den klein- sten Radius auf mit der Folge, daß der formschlüssig folgende Pum¬ penkolben 9 hier die größten Verzögerungen erfährt. Bei dem geschil¬ derten Ausführungsbeispiel hebt ein stark beschleunigter Pumpenkol¬ ben 9 vor OT von dem Stirnnocken 4 ab, wird jedoch durch die ge¬ dämpfte Abbremsung kurz nach OT in seinem Freiflug schnell begrenzt und rasch auf den Stirnnocken 4 zurückgeführt, wodurch die Funk¬ tionsfähigkeit des Nockentriebs erhöht wird. Die durch den Förder¬ hubdruck verursachten Querkräfte infolge der Torsion der Antriebs¬ welle 2 und der Verschiebungen des Nockentriebs können Verschlei߬ stellen verursachen, die zum Festlaufen des Pumpenkolbens 9 führen. Die zuvor beschriebene Formschlußtrennung zwischen Pumpenkolben 9 und Stirnnocken 4 vermeidet den Querkrafteinfluß auf den Pumpen¬ kolben vor OT; damit wird der Lagerverschleiß des Pumpenkolbens 9 weitgehend umgangen. Das geschilderte Ausführungsbeispiel erlaubt somit durch das Abfangen des oszillierenden Pumpenkolbens 9 mittels der hydraulischen Zusatzkraft in der erfindungsgemäßen Art bei ge¬ ringerer Verschleißanfälligkeit höhere Fördergeschwindigkeiten bzw. Antriebsdrehzahlen der Kraftstoffeinspritzpumpe oder höhere Hubzah¬ len des Pumpenkolbens pro Umdrehung bei gleicher Fördermenge, was eine Leistungssteigerung der Kraftstoffeinspritzpumpe zur Folge hat. The functional sequence described results in the following sequence of effects. The front cam 4 has its outer contour in TDC the small most radius with the result that the positive-locking pump piston 9 experiences the greatest delays here. In the exemplary embodiment described, a strongly accelerated pump piston 9 lifts off the front cam 4 before TDC, but is quickly limited and quickly returned to the front cam 4 by the damped braking shortly after TDC in its free flight, as a result of which the radio ability of the cam drive is increased. The transverse forces caused by the delivery stroke pressure as a result of the torsion of the drive shaft 2 and the displacements of the cam drive can cause wear points which lead to the pump piston 9 jamming. The previously described positive locking separation between pump piston 9 and front cam 4 avoids the influence of transverse forces on the pump piston before TDC; this largely avoids the bearing wear of the pump piston 9. The exemplary embodiment described thus allows, by intercepting the oscillating pump piston 9 by means of the additional hydraulic force in the manner according to the invention with lower susceptibility to wear, higher delivery speeds or drive speeds of the fuel injection pump or higher stroke numbers of the pump piston per revolution with the same delivery rate, which increases the performance of the fuel injection pump has the consequence.

Claims

Ansprüche Expectations
1. Kraftstoffeinspritzpumpe für Brennkraftmaschinen mit wenigstens einem von einem Nockenantrieb bewegten gestuften Pumpenkolben (9), dessen im Durchmesser kleinerer Teil in einer Bohrung (7) einer Zylinderbüchse (8) der Kraftstoffeinspritzpumpe zur KraftstoffVer¬ sorgung eines EinspritzSystems abwechselnd einen Saughub und einen Förderhub ausführt und dabei mit einer Stirnfläche einen Pumpen¬ arbeitsraum (14) begrenzt, mit einem mit einem Saugraum (26) der Kraftstoffeinspritzpumpe verbundenen Dämpfungsräum (22), dessen Volumen durch den Pumpenkolben (9) änderbar ist, und mit wenigstens einer, den Pumpenkolben (9) rückführenden und in Anlage mit dem Nockentrieb haltenden so wie sich am Gehäuse (1) abstützenden Rück¬ holfeder (17), dadurch gekennzeichnet, daß an dem im Durchmesser größeren Teil des Pumpenkolbens (9) eine in Förderrichtung des Pum¬ penkolbens (9) weisende Dämpfungsfläche (23) vorgesehen ist, die unter Bildung eines drosselnden, dann eine einzige Verbindung zum Saugraum bildenden Spaltes (25) am Ende des Förderhubs des Pum¬ penkolbens (9) in den Dämpfungsraum (22) einbringbar ist.1. Fuel injection pump for internal combustion engines with at least one stepped pump piston (9) moved by a cam drive, the smaller diameter part of which carries out a suction stroke and a delivery stroke alternately in a bore (7) of a cylinder liner (8) of the fuel injection pump for supplying fuel to an injection system and a pump working space (14) is delimited with an end face, with a damping space (22) connected to a suction space (26) of the fuel injection pump, the volume of which can be changed by the pump piston (9), and with at least one, the pump piston (9) returning return spring (17), which is in contact with the cam drive and is supported on the housing (1), characterized in that on the larger diameter part of the pump piston (9) a spring pointing in the conveying direction of the pump piston (9) Damping surface (23) is provided, which forms a throttling, then a single Ve Connection to the gap (25) forming the suction space at the end of the delivery stroke of the pump piston (9) can be introduced into the damping space (22).
2. Kraftstoffeinspritzpumpe nach Anspruch 1, dadurch gekennzeichnet, daß der Dämpfungsraum (22) radial begrenzt wird durch eine Dämp¬ fungsbohrung (24) und die Achsen der Dämpfungsbohrung (24) sowie der Bohrung (7) der Zylinderbüchse (8) gleich sind. 2. Fuel injection pump according to claim 1, characterized in that the damping space (22) is radially delimited by a damping bore (24) and the axes of the damping bore (24) and the bore (7) of the cylinder liner (8) are the same.
3. Kraftstoffeinspritzpumpe nach Anspruch 1, dadurch gekennzeichnet, daß die Dämpfungsfläche (23) aus einer stirnseitigen Ringfläche zwi¬ schen dem großen Durchmesser und dem kleinen Durchmesser des Pumpen¬ kolbens (9) gebildet ist.3. Fuel injection pump according to claim 1, characterized in that the damping surface (23) is formed from an end ring surface between the large diameter and the small diameter of the pump piston (9).
4. Kraftstoffeinspritzpumpe nach vorstehenden Ansprüchen, dadurch gekennzeichnet, daß die Dämpfungsfläche (23) den Eintrittsquer¬ schnitt des Dämpfungsraums (22) erst kurz nach der obersten, durch den Nockentrieb geführten Bewegungslage (OT) des Pumpenkolbens (9) erreicht.4. Fuel injection pump according to the preceding claims, characterized in that the damping surface (23) reaches the inlet cross-section of the damping chamber (22) only shortly after the uppermost movement position (TDC) of the pump piston (9) guided by the cam drive.
5. Kraftstoffeinspritzpumpe nach vorstehenden Ansprüchen, dadurch gekennzeichnet, daß der Spalt (25) gebildet wird durch das Bewe¬ gungsspiel zwischen der Mantelfläche des größeren Teils des Pumpen¬ kolbens (9) und einer den Dämpfungsraum (22) radial begrenzenden Dämpfungsbohrung (24). 5. Fuel injection pump according to the preceding claims, characterized in that the gap (25) is formed by the movement movement between the outer surface of the larger part of the pump piston (9) and the damping chamber (22) radially delimiting damping bore (24).
EP89909154A 1988-12-22 1989-08-17 Fuel injection pump for internal combustion engines Expired - Lifetime EP0422130B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3843162 1988-12-22
DE3843162A DE3843162A1 (en) 1988-12-22 1988-12-22 FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES

Publications (2)

Publication Number Publication Date
EP0422130A1 true EP0422130A1 (en) 1991-04-17
EP0422130B1 EP0422130B1 (en) 1992-05-13

Family

ID=6369796

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89909154A Expired - Lifetime EP0422130B1 (en) 1988-12-22 1989-08-17 Fuel injection pump for internal combustion engines

Country Status (7)

Country Link
US (1) US5127381A (en)
EP (1) EP0422130B1 (en)
KR (1) KR960010289B1 (en)
BR (1) BR8907259A (en)
DE (2) DE3843162A1 (en)
ES (1) ES2019764A6 (en)
WO (1) WO1990007055A1 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3943245A1 (en) * 1989-12-29 1991-07-04 Bosch Gmbh Robert FUEL INJECTION PUMP
US6126412A (en) * 1997-12-10 2000-10-03 Caterpillar Inc. Fluid driven piston assembly and fuel injector using same
DE10126686A1 (en) * 2001-06-01 2002-12-19 Bosch Gmbh Robert Fuel injection system, for an IC motor, has a pressure amplifier with a sliding piston and controlled outflow cross section stages to set the fuel pressure according to the piston stroke and give a boot injection action
ITCS20070034A1 (en) * 2007-07-12 2009-01-13 Ungaro S R L HEAT EXCHANGER FOR TERMINAL BOARD
WO2020248275A1 (en) * 2019-06-14 2020-12-17 胡永生 Feeding mechanism of wallboard forming machine for prefabricated integration

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2142704C3 (en) * 1971-08-26 1974-04-25 Robert Bosch Gmbh, 7000 Stuttgart Fuel injection pump for multi-cylinder internal combustion engines
DE2349581C2 (en) * 1973-10-03 1983-10-13 Robert Bosch Gmbh, 7000 Stuttgart Fuel distributor injection pump for internal combustion engines
DE3144277C2 (en) * 1981-11-07 1995-06-01 Bosch Gmbh Robert Fuel injection pump for internal combustion engines
DE3329384A1 (en) * 1983-08-13 1985-02-28 Robert Bosch Gmbh, 7000 Stuttgart Fuel injection pump for internal combustion engines
DE3336869A1 (en) * 1983-10-11 1985-04-25 Robert Bosch Gmbh, 7000 Stuttgart Fuel injection pump for multi-cylinder internal combustion engines
JPS61112771A (en) * 1984-11-06 1986-05-30 Nissan Motor Co Ltd Distributive fuel injection pump
DE3516455A1 (en) * 1985-05-08 1986-11-13 Robert Bosch Gmbh, 7000 Stuttgart FUEL INJECTION PUMP
DE3767260D1 (en) * 1986-09-25 1991-02-14 Ganser Hydromag FUEL INJECTION VALVE.
JPH01244144A (en) * 1988-03-25 1989-09-28 Yamaha Motor Co Ltd High pressure fuel injection device for engine

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9007055A1 *

Also Published As

Publication number Publication date
KR910700405A (en) 1991-03-15
US5127381A (en) 1992-07-07
KR960010289B1 (en) 1996-07-27
DE58901432D1 (en) 1992-06-17
EP0422130B1 (en) 1992-05-13
BR8907259A (en) 1991-03-12
WO1990007055A1 (en) 1990-06-28
DE3843162A1 (en) 1990-06-28
ES2019764A6 (en) 1991-07-01

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