EP0846224A1 - Fuel supply pump for a fuel injection pump for internal combustion engines - Google Patents

Fuel supply pump for a fuel injection pump for internal combustion engines

Info

Publication number
EP0846224A1
EP0846224A1 EP97915286A EP97915286A EP0846224A1 EP 0846224 A1 EP0846224 A1 EP 0846224A1 EP 97915286 A EP97915286 A EP 97915286A EP 97915286 A EP97915286 A EP 97915286A EP 0846224 A1 EP0846224 A1 EP 0846224A1
Authority
EP
European Patent Office
Prior art keywords
fuel
valve
opening
feed pump
chamber
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
EP97915286A
Other languages
German (de)
French (fr)
Other versions
EP0846224B1 (en
Inventor
Stanislaw Bodzak
Hanspeter Mayer
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 EP0846224A1 publication Critical patent/EP0846224A1/en
Application granted granted Critical
Publication of EP0846224B1 publication Critical patent/EP0846224B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C14/00—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations
    • F04C14/24—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves
    • F04C14/26—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves using bypass channels

Definitions

  • the invention is based on a fuel delivery pump for a fuel injection pump for internal combustion engines according to the preamble of claim 1.
  • Such a fuel delivery pump known from EP 0 166 995 B1 and designed as a gear delivery pump, delivers the fuel from a storage tank into the suction chamber of a fuel injection pump.
  • the feed pump has a pair of meshing teeth meshing with one another, which conveys fuel from an intake space connected to the storage tank via an intake line into a pressure space connected to the intake space of the fuel injection pump via a delivery line.
  • a bypass channel is provided between the pressure chamber and the suction chamber of the fuel delivery pump.
  • This bypass channel is opened by means of the Bypass channel used pressure valve, which releases a certain opening cross-section at a certain pressure difference between the pressure and suction space depending on the spring force of the valve spring.
  • the opening time of the pressure valve can be adjusted via the biasing force of the valve spring, for which purpose the axial position of the abutment of the pressure valve spring is adjustable.
  • the known KraftStoff feed pump has the disadvantage that the bypass channel receiving the pressure valve is arranged outside the feed pump or spatially relatively far from the gear pair, which results in increased construction and assembly costs and a large amount of space.
  • Both fuel feed pumps have the disadvantage that when the fuel feed pump is at a standstill, the fuel present in the pump chamber flows into the suction line leading to the fuel feed pump and the fuel feed pump can empty itself. This may require ventilation of the suction line to be restarted.
  • the fuel feed pump according to the invention for a fuel injection pump for internal combustion engines has the advantage over the fact that a check valve which can be closed off the intake space of the fuel feed pump Emptying of the fuel delivery pump prevented when the engine is not running.
  • fuel can be supplied to the internal combustion fuel injection pump immediately after a restart of the fuel delivery pump, so that the required delivery pressure for the fuel can be built up within a short time.
  • a check valve that closes the intake chamber high starting efficiency can be achieved.
  • the fuel delivery pump remains wetted with fuel when the engine is not running, so that no corrosion can occur.
  • the check valve in an opening of the housing leading to the intake chamber, so that a fuel delivery pump can be designed with a small installation space.
  • the check valve closing the intake space also has the advantage of acting as a flow resistance with a throttling effect in the operation of the fuel delivery pump.
  • throttling the fuel in the suction line By throttling the fuel in the suction line, the flow rate can be reduced as the speed increases. This allows a smooth transition from the steadily increasing flow rate to the maximum flow rate to be achieved, whereby a low workload is required to deliver the fuel.
  • the excess is usually controlled by a pressure relief valve. This makes it possible for the pump characteristic curve to be adapted to a demand characteristic curve, as a result of which less heating of the fuel delivery pump can be achieved due to the smaller quantity throttled.
  • the check valve acts as a suction throttle when the speed and delivery rate increase.
  • the suction throttle only allows a certain amount to pass before and after the throttle at a given pressure difference. Since the Suction throttle is inserted in the suction line, the maximum pressure difference can only be approx. 1 bar. This corresponds to a difference between ambient air pressure and vacuum. When the negative pressure increases, however, the vapor pressure and the degassing pressure of the fuel fall below. The fuel thus foams up behind the throttle, increases the volume and the foamed fuel gets into the pump chamber and is converted back into the liquid phase during the compression phase. The resulting volume reduction is compensated for by fuel flowing back from the pressure chamber. This means that the pump effectively delivers less volume per unit of time from a certain "critical" speed. As a result, if there is a defined need, less excess fuel must be shut off via the pressure relief valve.
  • a multi-substance pump for example for lubricating oil, can also be designed according to the features of claim 1.
  • Feed pump along the line II of Fig. 2, 2 is a plan view of the fuel feed pump shown in FIG. 1 with the cover removed,
  • FIG. 3 shows a section through FIG. 2 along the line III-III, in which the position of the bypass channel and the pressure valve arranged therein as well as the arrangement according to the invention of a pressure valve in an opening of the housing is shown,
  • FIGS. 3 and 4 shows an alternative embodiment of the pressure valve to FIGS. 3 and
  • a first embodiment of a fuel delivery pump is shown in different views, which is inserted into an inlet line, not shown, from a storage tank to a fuel injection pump for internal combustion engines.
  • the feed pump has in its housing 1 a pump chamber 3 in which a rotatingly driven pair of meshing gears 7, 9 is arranged.
  • a first gearwheel 7 fastened on a shaft 5 is driven in rotation by means of an external drive element (not shown in any more detail) and transmits this rotary movement by means of a spur toothing to a second gearwheel 9 which meshes with the first gearwheel 7 and is arranged on an axle 11 mounted in the housing.
  • the gears 7, 9 share the Pump chamber 3 through its tooth engagement in two parts, of which a first part form a suction chamber 13 and a second part a pressure chamber 15.
  • the suction chamber 13 is connected to the pressure chamber 15 via a respective delivery channel 17 formed between the tooth grooves on the end face of the first gear 7 and the second gear 9 and the circumference of the pump edge 3.
  • the suction chamber 13 and the pressure chamber 15 each have a connection opening 19, 21 in the wall of the pump housing 1, via which the suction chamber 13 with a connection element 14 of a suction line, not shown, from the storage tank and the pressure chamber 15 with a delivery line, not shown, to the suction chamber the fuel injection pump is connected.
  • connection opening in the suction chamber 13 forms an inlet opening 19 and the connection opening in the pressure chamber 15 forms an outlet opening 21.
  • the pump chamber 3 is closed on one end side in the axial direction of the shafts 5 and the axis 11 by a housing cover 23, which in the illustration of FIG Fig. 2 was removed and thus allows a view of the pump interior.
  • a bypass duct 25 is also provided in the pump housing 1 for pressure control of the delivery pressure in the pressure chamber 15.
  • This bypass channel 25 is formed by a bore in a housing web 27 delimiting the pump chamber 3 on its end face facing away from the housing cover 23, separating the pressure from the suction side and thereby forming a pump chamber wall.
  • the bore forming the bypass channel 25 is arranged such that its cross section, projected in the axial direction, lies completely within the clear cross section of the inlet opening 19.
  • the hole forming the bypass channel 25 is listed as a through hole, one end of which in the pressure chamber 15 and the other end opens into the intake chamber 13.
  • the bypass channel 25 has a cross-sectional reduction in the direction of the pressure chamber 15, which is formed by a bore shoulder, the bypass channel-side annular shoulder forming a valve seat 29 of a pressure valve 31 set in the bypass channel 25.
  • a valve closing member 33 of the pressure valve 31 comes into contact with a sealing surface 35 formed on its end face on the pressure chamber side due to the force of a valve spring 37.
  • This valve spring 37 in the bypass channel 25 engages via a shoulder on the valve closing member 33 and, on the other hand, is supported on a clamping sleeve 39 inserted into the end of the bypass channel 25 on the suction chamber side.
  • This clamping sleeve 39 can be used analogously to the other components of the pressure valve 31 via the inlet opening 19 into the bypass channel 25, the clamping sleeve 39, which releases a flow cross section, the prestressing force of the valve spring 37 and thus the opening pressure of the pressure valve 31 in the bypass channel via the axial installation depth 25 the pressure chamber 15 and the suction chamber 13 is adjustable.
  • the clamping sleeve 39 can be pressed into the bypass channel 25 or screwed in by means of a thread, so that a very precise axial position fixing of the clamping sleeve 39 is possible.
  • This hose connector 14 can be pressed into the housing 1 by means of a quick-release fastener or screwed in by means of a thread or can be fastened to the housing 1 by means of a sinew connection.
  • a valve closing member 41 is guided, which closes the suction chamber 13 with respect to an inlet line, not shown, from a storage tank to the fuel delivery pump.
  • the Valve closing member 41 has a diameter corresponding to the opening cross section of the inlet opening 19 and can be moved axially in the inlet opening 19 against a valve spring 44.
  • the end of the hose connector 14 facing the suction space 13 forms a cross-sectional reduction of the inlet opening 19, through which a valve seat 42 of a check valve 40 inserted in the inlet opening 19 is formed.
  • the valve closing member 41 of the check valve 40 comes into contact with a sealing surface 43 which faces the hose connector 14 as a result of the force of the valve spring 44.
  • This valve spring 44 in the inlet opening 19 engages via a shoulder on the valve closing member 41 and, on the other hand, is supported on the clamping sleeve 39 inserted into the end of the bypass channel 25 on the suction chamber side.
  • This clamping sleeve 39 penetrates the suction space 13 and adjoins the inlet opening 19.
  • the inlet opening 19 has a cross section which corresponds to the outer diameter of the clamping sleeve 39, so that the valve spring 44 can be supported on the end face of the clamping sleeve 39.
  • the pretensioning force of the valve spring 44 can be adjusted by the length of the clamping sleeve 39, which can also extend into the inlet opening 19, and also by the immersion depth of the hose connector 14 in the inlet opening 19, so that a certain opening pressure of the pressure valve 40 in the inlet opening 19 is adjustable.
  • the pressure valves 31 and 40 are advantageously constructed identically, so that an inexpensive configuration is possible. Furthermore, the pressure valve 31 and the check valve 40 operate independently of one another.
  • the clamping sleeve 39 has in its area penetrating the suction space 13 opening slots, so that the over a fuel line (not shown) of the fuel feed pump can flow past the check valve 40 and can be fed to the suction chamber 13 via the opening slots of the clamping sleeve 39.
  • the fuel returned from the pressure chamber 15 into the bypass channel 25 can also be returned to the intake chamber 13 via this slot-shaped opening.
  • FIG. 4 shows an alternative embodiment of a check valve 50 compared to the check valve 40 in FIG. 3.
  • the check valve 50 according to FIG. 4 is designed as a structural unit and has an annular cross section 51 which bears on a shoulder 52 of the inlet opening 19.
  • a connecting element 14 is screwed or pressed into the inlet opening 19.
  • a fuel line, not shown, can be connected to this connecting element 14.
  • a cup-shaped housing 53 adjoins the ring cross section 51, in which a valve spring 54 is mounted, which brings a valve closing member 56 into contact with the ring cross section 51.
  • the ring cross section 51 is designed as a valve seat. The valve closing member 56 can be deflected by the fuel against the valve spring 54.
  • the openings 59 act analogously to the depressions arranged in the valve closing member 41 in the circumferential wall as a throttle , which can reduce the flow rate of the fuel with increasing speed of the fuel delivery pump.
  • the clamping sleeve 39 is shortened compared to the embodiment in FIG. 3, so that it can be inserted completely in the bypass channel 25.
  • the check valve 50 is integrated in a connection element 14, so that the connection element 14 can be easily assembled with a check valve 50 integrated therein.
  • the valve closing member 56 is designed as a ball or the like.
  • the pressure valve 31 and the check valves 40, 50 can be made of fuel- and temperature-resistant plastics or of metallic materials or in combination.
  • the fuel delivery pump operates in the following manner: When the internal combustion engine is operating, the fuel injection pump and the fuel delivery pump are driven in proportion to the speed of the internal combustion engine. This takes place in the feed pump shown in FIGS. 1 to 4 by means of a mechanical transmission element, not shown, which acts on the shaft 5 from the outside. Due to the rotation of the first gear 7 and the second gear 9 meshing with it, fuel is conveyed from the intake chamber 13 along the delivery channel 17 into the pressure chamber 15. This creates a negative pressure in the intake space 13, which is sufficient to open the check valve 40, 50 and to draw fuel from the storage tank via the intake line.
  • the fuel pressure built up in the pressure chamber 15 causes a fuel delivery from the latter via a delivery line into the suction chamber of the fuel injection pump to be supplied.
  • the check valve 40, 50 acts as a throttle, which has a smooth transition of the characteristic curve 60 compared to a theoretical course of the characteristic curve 61 according to FIG. 5, which would also correspond to a characteristic curve if there were no check valve 40, 50.
  • the horizontal line 62 is determined by the maximum delivery flow of the fuel delivery pump as a function of the opening pressure of the pressure valve 31 in the bypass channel 25.
  • the throttling effect is based on the fact that recesses are arranged in the valve closing member 41 which are uniformly distributed over the circumference, which enable the fuel to flow to the suction chamber 13 via these openings after lifting the valve closing member 41 from the valve seat 42.
  • the fuel flows after the valve closing member 56 has been lifted off the valve seat 51 via openings 59 in the housing 53 to the intake chamber.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel-Injection Apparatus (AREA)

Abstract

The invention relates to a fuel supply pump for a fuel injection pump for internal combustion engines, with a driven pair of meshing pinions (7, 9) rotating in a pump chamber (3) or other rotary conveying components which feed the fuel from a suction chamber (13) connected to a tank along a supply channel (17) formed between the faces of the pinions (7, 9) and the peripheral wall of the pump chamber (3) to a pressure chamber (15) connected to the fuel injection pump, and with a by-pass channel (25), integrated into a housing (1) of the fuel supply pump and connecting the suction (13) and pressure (15) chambers, which can be controlled by means of a pressure valve (31) fitted therein, where the suction chamber (13) can be closed by a check valve (40) acting against the fuel supply device.

Description

Kraftstoff-Förderpumpe für eine Kraftstoff-Einspritzpumpe für Brennkraftmaschinen Fuel feed pump for a fuel injection pump for internal combustion engines
Stand der TechnikState of the art
Die Erfindung geht von einer Kraftstoff-Förderpumpe für eine Kraftstoff-Einspritzpumpe für Brennkraftmaschinen nach der Gattung des Patentanspruchs 1 aus.The invention is based on a fuel delivery pump for a fuel injection pump for internal combustion engines according to the preamble of claim 1.
Eine derartige, aus der EP 0 166 995 Bl bekannte, als Zahnradförderpumpe ausgebildete Kraftstoff-Förderpumpe fördert den Kraftstoff aus einem Vorratstank in den Saugraum einer Kraftstoff-Einspritzpumpe. Dazu weist die Förderpumpe ein im Außeneingriff kämmendes Zahnradpaar auf, das Kraftstoff aus einem über eine Ansaugleitung mit dem Vorratstank verbundenen Ansaugraum in einen, über eine Förderleitung mit dem Saugraum der Kraftstoff-Einspritzpumpe verbundenen Druckraum fördert. Dabei ist zur Steuerung des Drucks im Druckraum bzw. der Fördermenge zur Kraftstoff- Einspritzpumpe ein Bypasskanal zwischen dem Druckraum und dem Ansaugraum der Kraftstoff-Förderpumpe vorgesehen. Das Aufsteuern dieses Bypasskanals erfolgt dabei mittels in dem Bypasskanal eingesetzten Druckventils, das bei einer bestimmten Druckdifferenz zwischen Druck- und Ansaugraum in Abhängigkeit von der Federkraft der Ventilfeder einen bestimmten Öffnungsguerschnitt freigibt. Der Öffnungszeitpunkt des Druckventils läßt sich dabei über die Vorspannkraft der Ventilfeder verstellen, wozu die axiale Lage des Widerlagers der Druckventilfeder verstellbar ist.Such a fuel delivery pump, known from EP 0 166 995 B1 and designed as a gear delivery pump, delivers the fuel from a storage tank into the suction chamber of a fuel injection pump. For this purpose, the feed pump has a pair of meshing teeth meshing with one another, which conveys fuel from an intake space connected to the storage tank via an intake line into a pressure space connected to the intake space of the fuel injection pump via a delivery line. To control the pressure in the pressure chamber or the flow rate to the fuel injection pump, a bypass channel is provided between the pressure chamber and the suction chamber of the fuel delivery pump. This bypass channel is opened by means of the Bypass channel used pressure valve, which releases a certain opening cross-section at a certain pressure difference between the pressure and suction space depending on the spring force of the valve spring. The opening time of the pressure valve can be adjusted via the biasing force of the valve spring, for which purpose the axial position of the abutment of the pressure valve spring is adjustable.
Dabei weist die bekannte KraftStoff-Förderpumpe jedoch den Nachteil auf, daß der das Druckventil aufnehmende Bypasskanal außerhalb der Förderpumpe bzw. räumlich relativ weit vom Zahnradpaar angeordnet ist, was einen erhöhten Bau- und Montageaufwand sowie einen hohen Bauraum zur Folge hat.However, the known KraftStoff feed pump has the disadvantage that the bypass channel receiving the pressure valve is arranged outside the feed pump or spatially relatively far from the gear pair, which results in increased construction and assembly costs and a large amount of space.
Aus der deutschen Patentanmeldung P 44 41 505.2 ist eine Kraftstoff-Förderpumpe bekannt, die die oben genannten Nachteile vermeidet. Der das Druckventil aufnehmende Bypasskanal ist in das Gehäuse der Förderpumpe integriert, so daß kein zusätzlicher Bauraum beansprucht wird.From the German patent application P 44 41 505.2 a fuel delivery pump is known which avoids the disadvantages mentioned above. The bypass channel receiving the pressure valve is integrated in the housing of the feed pump, so that no additional installation space is required.
Beide Kraftstoff-Förderpumpen weisen jedoch den Nachteil auf, daß bei stillstehender Kraftstoff-Förderpumpe der in der Pumpkammer vorhandene Kraftstoff in die zur Kraftstoff- Förderpumpe führende Saugleitung strömen und die Kraftstoff- Förderpumpe sich entleeren kann. Dadurch bedarf es unter Umständen bei einem Neustart der Entlüftung der Saugleitung.Both fuel feed pumps, however, have the disadvantage that when the fuel feed pump is at a standstill, the fuel present in the pump chamber flows into the suction line leading to the fuel feed pump and the fuel feed pump can empty itself. This may require ventilation of the suction line to be restarted.
Vorteile der ErfindungAdvantages of the invention
Die erfindungsgemäße Kraftstoff-Förderpumpe für eine Kraftstoff-Einspritzpumpe für Brennkraftmaschinen hat demgegenüber den Vorteil, daß ein den Ansaugraum der Kraftstoff-Förderpumpe verschließbares Rückschlagventil ein Entleeren der Kraftstoff-Förderpumpe bei Motorstillstand verhindert. Dadurch kann unmittelbar nach einem Neuεtart der Kraftstoff-Förderpumpe der Brennkraft-Einspritzpumpe Kraftstoff zugeführt werden, so daß innerhalb kurzer Zeit der erforderliche Förderdruck für den Kraftstoff aufgebaut werden kann. Durch die Anordnung eines Rückschlagventiles, das den Ansaugraum schließt, kann somit ein hoher Wirkungsgrad beim Starten erzielt werden. Desweiteren ist vorteilhaft, daß die Kraftstoff-Förderpumpe bei Motorstillstand mit Kraftstoff benetzt bleibt, so daß keine Korrosion auftreten kann. Dabei ist es besonders vorteilhaft, das Rückschlagventil in einer zum Ansaugraum führenden Öffnung des Gehäuses anzuordnen, so daß eine Kraftstoff-Förderpumpe mit einem geringen Bauraum ausgebildet werden kann.The fuel feed pump according to the invention for a fuel injection pump for internal combustion engines has the advantage over the fact that a check valve which can be closed off the intake space of the fuel feed pump Emptying of the fuel delivery pump prevented when the engine is not running. As a result, fuel can be supplied to the internal combustion fuel injection pump immediately after a restart of the fuel delivery pump, so that the required delivery pressure for the fuel can be built up within a short time. By arranging a check valve that closes the intake chamber, high starting efficiency can be achieved. It is also advantageous that the fuel delivery pump remains wetted with fuel when the engine is not running, so that no corrosion can occur. It is particularly advantageous to arrange the check valve in an opening of the housing leading to the intake chamber, so that a fuel delivery pump can be designed with a small installation space.
Das den Ansaugraum verschließende Rückschlagventil weist darüber hinaus den Vorteil auf, als Strömungswiderstand mit einer Drosselwirkung im Betrieb der Kraftstoff-Förderpumpe zu wirken. Durch die Drosselung des Kraftstoffs in der Saugleitung kann der Förderstrom bei steigender Drehzahl verringert werden. Dadurch kann ein sanfter Übergang von dem stetig ansteigenden Förderstrom zum maximalen Förderstrom erzielt werden, wodurch zur Förderung des Kraftstoffes eine geringe Arbeitsleistung erforderlich ist. Die Übermenge wird üblicherweise über ein Druckbegrenzungsventil abgesteuert. Dadurch ist ermöglicht, daß die Pumpenkennlinie an eine Bedarfskennlinie angepaßt sein kann, wodurch aufgrund der geringeren abgedrosselten Menge eine geringere Erwärmung der Kraftstoff-Förderpumpe erzielt werden kann. Gleichzeitig wirkt das Rückschlagventil bei steigender Drehzahl und Fördermenge als Saugdrossel. Dies bedeutet, daß die Saugdrossel bei einer gegebenen Druckdifferenz vor und nach der Drossel nur eine bestimmte Menge durchläßt. Da die Saugdrossel in der Saugleitung eingebracht ist, kann die maximale Druckdifferenz nur ca. 1 bar betragen. Dies entspricht einer Differenz zwischen Umgebungs-Luftdruck und Vakuum. Bei Steigerung des Unterdruckes wird aber der Dampfdruck und der Entgasungsdruck des Kraftstoffes unterschritten. Der Kraftstoff schäumt somit hinter der Drossel auf, vergrößert das Volumen und der geschäumte Kraftstoff gelangt in die Pumpenkammer und wird während der Verdichtungsphase wieder in die flüssige Phase übergeführt. Die dabei auftretende Volumenverminderung wird durch rückströmenden Kraftstoff aus der Druckkammer ausgeglichen. Dies bedeutet, daß die Pumpe ab einer bestimmten "kritischen" Drehzahl effektiv weniger Volumen pro Zeiteinheit fördert. Dadurch muß bei einem definierten Bedarf weniger Übermenge an Kraftstoff über das Druckbegrenzungsventil abgesteuert werden.The check valve closing the intake space also has the advantage of acting as a flow resistance with a throttling effect in the operation of the fuel delivery pump. By throttling the fuel in the suction line, the flow rate can be reduced as the speed increases. This allows a smooth transition from the steadily increasing flow rate to the maximum flow rate to be achieved, whereby a low workload is required to deliver the fuel. The excess is usually controlled by a pressure relief valve. This makes it possible for the pump characteristic curve to be adapted to a demand characteristic curve, as a result of which less heating of the fuel delivery pump can be achieved due to the smaller quantity throttled. At the same time, the check valve acts as a suction throttle when the speed and delivery rate increase. This means that the suction throttle only allows a certain amount to pass before and after the throttle at a given pressure difference. Since the Suction throttle is inserted in the suction line, the maximum pressure difference can only be approx. 1 bar. This corresponds to a difference between ambient air pressure and vacuum. When the negative pressure increases, however, the vapor pressure and the degassing pressure of the fuel fall below. The fuel thus foams up behind the throttle, increases the volume and the foamed fuel gets into the pump chamber and is converted back into the liquid phase during the compression phase. The resulting volume reduction is compensated for by fuel flowing back from the pressure chamber. This means that the pump effectively delivers less volume per unit of time from a certain "critical" speed. As a result, if there is a defined need, less excess fuel must be shut off via the pressure relief valve.
Erfindungsgemäß kann auch eine Vielstoffpumpe, beispielsweise für Schmieröl, gemäß den Merkmalen des Anspruchs 1 ausgebildet sein.According to the invention, a multi-substance pump, for example for lubricating oil, can also be designed according to the features of claim 1.
Weitere Vorteile und vorteilhafte Ausgestaltungen des Gegenstandes der Erfindung sind der Beschreibung, der Zeichnung und den Patentansprüchen entnehmbar.Further advantages and advantageous configurations of the subject matter of the invention can be gathered from the description, the drawing and the patent claims.
Zeichnungdrawing
In der Zeichnung sind zwei Ausfuhrungsbeispiele der erfindungsgemäßen Kraftstoff-Förderpumpe dargestellt und in der nachfolgenden Beschreibung näher erläutert. Es zeigen:In the drawing, two exemplary embodiments of the fuel delivery pump according to the invention are shown and explained in more detail in the following description. Show it:
Fig. 1 einen Längsschnitt durch die Kraftstoff-1 is a longitudinal section through the fuel
Förderpumpe entlang der Linie I-l von Fig. 2, Fig. 2 eine Draufsicht auf die in Fig. l dargestellte Kraftstoff-Förderpumpe mit abgenommenem Deckel,Feed pump along the line II of Fig. 2, 2 is a plan view of the fuel feed pump shown in FIG. 1 with the cover removed,
Fig. 3 einen Schnitt durch die Fig. 2 entlang der Linie III-III, in dem die Lage des Bypasskanals und des darin angeordneten Druckventils als auch die erfindungsgemäße Anordnung eines Druckventils in einer Öffnung des Gehäuses dargestellt ist,3 shows a section through FIG. 2 along the line III-III, in which the position of the bypass channel and the pressure valve arranged therein as well as the arrangement according to the invention of a pressure valve in an opening of the housing is shown,
Fig. 4 eine alternative Ausfuhrungsform des Druck¬ ventils zu Fig. 3 und4 shows an alternative embodiment of the pressure valve to FIGS. 3 and
Fig. 5 ein Kennliniendiagramm zum Ausführungsbeispiel nach Fig. 3 und 4.5 shows a characteristic diagram for the exemplary embodiment according to FIGS. 3 and 4.
Beschreibung der AusfuhrungsbeispieleDescription of the exemplary embodiments
In den Fig. 1 bis 3 ist in verschiedenen Ansichten eine erste Ausfuhrungsform einer Kraftstoff-Förderpumpe dargestellt, die in eine nicht dargestellte Zulaufleitung von einem Vorratstank zu einer Kraftstoff-Einspritzpumpe für Brennkraftmaschinen eingesetzt ist. Dabei weist die Förderpumpe in ihrem Gehäuse 1 eine Pumpkammer 3 auf, in der ein rotierend angetriebenes Paar miteinander kämmender Zahnräder 7, 9 angeordnet ist. Dabei wird ein auf einer Welle 5 befestigtes erstes Zahnrad 7 mittels eines nicht näher dargestellten externen Antriebselementes rotierend angetrieben und überträgt diese Drehbewegung mittels einer Stirnverzahnung auf ein mit dem ersten Zahnrad 7 kämmendes zweites Zahnrad 9, das auf einer gehäusegelagerten Achse 11 angeordnet ist. Die Zahnräder 7, 9 teilen dabei die Pumpkammer 3 durch ihren Zahneingriff in zwei Teile, von denen ein erster Teil einen Ansaugraum 13 und ein zweiter Teil einen Druckraum 15 bilden. Der Ansaugraum 13 ist dabei über je einen zwischen den Zahnnuten an der Stirnfläche des ersten Zahnrades 7 und des zweiten Zahnrades 9 und der Umfangs von der Pumpenrand 3 gebildeten Förderkanals 17 mit dem Druckraum 15 verbunden. Zudem weist der Ansaugraum 13 und der Druckraum 15 jeweils eine Anschlußδffnung 19, 21 in der Wand des Pumpengehäuses 1 auf, über die der Ansaugraum 13 mit einem Anschlußelement 14 einer nicht näher dargestellten Ansaugleitung vom Vorratstank und der Druckraum 15 mit einer nicht dargestellten Förderleitung zum Saugraum der Kraftstoff-Einspritzpumpe verbunden ist. Dabei bildet die Anschlußöffnung in den Ansaugraum 13 eine Einlaßöffnung 19 und die Anschlußöffnung in den Druckraum 15 eine Auslaßöffnung 21. Die Pumpkammer 3 ist auf ihrer einen Stirnseite in Achsrichtung der Wellen 5 und der Achse 11 von einem Gehäusedeckel 23 verschlossen, der in der Darstellung der Fig. 2 abgenommen wurde und so eine Ansicht des Pumpeninneren ermöglicht.1 to 3, a first embodiment of a fuel delivery pump is shown in different views, which is inserted into an inlet line, not shown, from a storage tank to a fuel injection pump for internal combustion engines. The feed pump has in its housing 1 a pump chamber 3 in which a rotatingly driven pair of meshing gears 7, 9 is arranged. In this case, a first gearwheel 7 fastened on a shaft 5 is driven in rotation by means of an external drive element (not shown in any more detail) and transmits this rotary movement by means of a spur toothing to a second gearwheel 9 which meshes with the first gearwheel 7 and is arranged on an axle 11 mounted in the housing. The gears 7, 9 share the Pump chamber 3 through its tooth engagement in two parts, of which a first part form a suction chamber 13 and a second part a pressure chamber 15. The suction chamber 13 is connected to the pressure chamber 15 via a respective delivery channel 17 formed between the tooth grooves on the end face of the first gear 7 and the second gear 9 and the circumference of the pump edge 3. In addition, the suction chamber 13 and the pressure chamber 15 each have a connection opening 19, 21 in the wall of the pump housing 1, via which the suction chamber 13 with a connection element 14 of a suction line, not shown, from the storage tank and the pressure chamber 15 with a delivery line, not shown, to the suction chamber the fuel injection pump is connected. The connection opening in the suction chamber 13 forms an inlet opening 19 and the connection opening in the pressure chamber 15 forms an outlet opening 21. The pump chamber 3 is closed on one end side in the axial direction of the shafts 5 and the axis 11 by a housing cover 23, which in the illustration of FIG Fig. 2 was removed and thus allows a view of the pump interior.
Für eine Drucksteuerung des Förderdruckes im Druckraum 15 ist desweiteren ein Bypasskanal 25 im Pumpengehäuse 1 vorgesehen. Dieser Bypasskanal 25 wird durch eine Bohrung in einem, die Pumpkammer 3 auf ihrer dem Gehäusedeckel 23 abgewandten Stirnseite begrenzenden, den Druck von der Saugseite trennenden und dabei eine Pumpenkammerwand bildenden Gehäusesteg 27 gebildet. Dabei ist die den Bypasskanal 25 bildende Bohrung so angeordnet, daß ihr Querschnitt in axialer Richtung projeziert vollständig innerhalb des lichten Querschnitts der Einlaßöffnung 19 liegt. Die den Bypasskanal 25 bildende Bohrung ist als Durchgangsbohrung aufgeführt, deren eines Ende in den Druckraum 15 und deren anderes Ende in den Ansaugraum 13 mündet. Am druckseitigen Ende weist der Bypasskanal 25 eine durch einen Bohrungsabsatz gebildete Querschnittsverringerung in Richtung Druckraum 15 auf, wobei die gebildete bypasskanalseitige Ringschulter einen Ventilsitz 29 eines in dem Bypasskanal 25 gesetzten Druckventils 31 bildet. An diesem Ventilsitz 29 kommt ein Ventilschließglied 33 des Druckventils 31 mit einer an seiner druckraumseitigen Stirnseite gebildeten Dichtfläche 35 infolge der Kraft einer Ventilfeder 37 zur Anlage. Diese Ventilfeder 37 im Bypasskanal 25 greift dabei über einen Absatz am Ventilschließglied 33 an und stützt sich andererseits an einer in das saugraumseitige Ende des Bypasskanals 25 eingesetzten Spannhülse 39 ab. Diese Spannhülse 39 ist dabei analog zu den übrigen Bauteilen des Druckventils 31 über die Einlaßöffnung 19 in den Bypasskanal 25 einsetzbar, wobei über die axiale Einbautiefe der, einen Durchflußquerschitt freigebenden, Spannhülse 39 die Vorspannkraft der Ventilfeder 37 und somit der Öffnungsdruck des Druckventils 31 im Bypasskanal 25 dem Druckraum 15 und dem Ansaugraum 13 einstellbar ist. Die Spannhülse 39 kann dabei in den Bypasskanal 25 eingepreßt oder mittels eines Gewindes eingeschraubt sein, so daß eine sehr genaue axiale Lagefixierung der Spannhülse 39 möglich ist.A bypass duct 25 is also provided in the pump housing 1 for pressure control of the delivery pressure in the pressure chamber 15. This bypass channel 25 is formed by a bore in a housing web 27 delimiting the pump chamber 3 on its end face facing away from the housing cover 23, separating the pressure from the suction side and thereby forming a pump chamber wall. The bore forming the bypass channel 25 is arranged such that its cross section, projected in the axial direction, lies completely within the clear cross section of the inlet opening 19. The hole forming the bypass channel 25 is listed as a through hole, one end of which in the pressure chamber 15 and the other end opens into the intake chamber 13. At the pressure-side end, the bypass channel 25 has a cross-sectional reduction in the direction of the pressure chamber 15, which is formed by a bore shoulder, the bypass channel-side annular shoulder forming a valve seat 29 of a pressure valve 31 set in the bypass channel 25. At this valve seat 29, a valve closing member 33 of the pressure valve 31 comes into contact with a sealing surface 35 formed on its end face on the pressure chamber side due to the force of a valve spring 37. This valve spring 37 in the bypass channel 25 engages via a shoulder on the valve closing member 33 and, on the other hand, is supported on a clamping sleeve 39 inserted into the end of the bypass channel 25 on the suction chamber side. This clamping sleeve 39 can be used analogously to the other components of the pressure valve 31 via the inlet opening 19 into the bypass channel 25, the clamping sleeve 39, which releases a flow cross section, the prestressing force of the valve spring 37 and thus the opening pressure of the pressure valve 31 in the bypass channel via the axial installation depth 25 the pressure chamber 15 and the suction chamber 13 is adjustable. The clamping sleeve 39 can be pressed into the bypass channel 25 or screwed in by means of a thread, so that a very precise axial position fixing of the clamping sleeve 39 is possible.
In der Einlaßöffnung 19 ist ein Element 14, das als Schlauchstutzen ausgebildet ist, eingesetzt. Dieser Schlauchstutzen 14 kann mittels eines Schnellverschlußes zum Gehäuse 1 eingepreßt oder mittels eines Gewindes eingeschraubt oder mittels einer Sehne11Verbindung zum Gehäuse 1 befestigbar sein. In der Einlaßöffnung 19 ist ein Ventilschließglied 41 geführt, das den Ansaugraum 13 gegenüber einer nicht dargestellten Zulaufleitung von einem Vorratstank zur Kraftstoff-Förderpumpe schließt. Das Ventilschließglied 41 weist eine den Öffnungsguerschnitt der Einlaßöffnung 19 entsprechenden Durchmesser auf und ist axial in der Einlaßöffnung 19 entgegen einer Ventilfeder 44 bewegbar. Das zum Ansaugraum 13 weisende Ende des Schlauchstutzens 14 bildet eine Querschnittsverringerung der Einlaßöffnung 19, durch die ein Ventilsitz 42 eines in der Einlaßöffnung 19 eingesetzten Rückschlagventils 40 gebildet ist. An diesem Ventilsitz 42 kommt das Ventilschließglied 41 des Rückschlagventils 40 mit einer an seiner zum Schlauchstutzen 14 weisenden Dichtfläche 43 infolge der Kraft der Ventilfeder 44 zur Anlage. Diese Ventilfeder 44 in der Einlaßöffnung 19 greift dabei über einen Absatz am Ventilschließglied 41 an und stützt sich andererseits an der in das saugraumseitige Ende des Bypasskanals 25 eingesetzten Spannhülse 39 ab. Diese Spannhülse 39 durchdringt den Ansaugraum 13 und grenzt an die Einlaßöffnung 19 an.An element 14, which is designed as a hose connector, is inserted in the inlet opening 19. This hose connector 14 can be pressed into the housing 1 by means of a quick-release fastener or screwed in by means of a thread or can be fastened to the housing 1 by means of a sinew connection. In the inlet opening 19, a valve closing member 41 is guided, which closes the suction chamber 13 with respect to an inlet line, not shown, from a storage tank to the fuel delivery pump. The Valve closing member 41 has a diameter corresponding to the opening cross section of the inlet opening 19 and can be moved axially in the inlet opening 19 against a valve spring 44. The end of the hose connector 14 facing the suction space 13 forms a cross-sectional reduction of the inlet opening 19, through which a valve seat 42 of a check valve 40 inserted in the inlet opening 19 is formed. At this valve seat 42, the valve closing member 41 of the check valve 40 comes into contact with a sealing surface 43 which faces the hose connector 14 as a result of the force of the valve spring 44. This valve spring 44 in the inlet opening 19 engages via a shoulder on the valve closing member 41 and, on the other hand, is supported on the clamping sleeve 39 inserted into the end of the bypass channel 25 on the suction chamber side. This clamping sleeve 39 penetrates the suction space 13 and adjoins the inlet opening 19.
Die Einlaßöffnung 19 weist einen Querschnitt auf, der dem Außendurchmesser der Spannhülse 39 entspricht, so daß die Ventilfeder 44 sich an der Stirnfläche der Spannhülse 39 abstützen kann. Durch die Länge der Spannhülse 39, die sich auch in die Einlaßöffnung 19 erstrecken kann, als auch durch die Eintauchtiefe des Schlauchstutzens 14 in die Einlaßöffnung 19, ist die Vorspannkraft der Ventilfeder 44 einstellbar, so daß ein bestimmter Öffnungsdruck des Druckventils 40 in der Einlaßöffnung 19 einstellbar ist. Die Druckventile 31 und 40 sind vorteilhafterweise baugleich ausgeführt, so daß eine kostengünstige Ausgestaltung möglich ist. Desweiteren arbeiten das Druckventil 31 und das Rückschlagventil 40 unabhängig voneinander.The inlet opening 19 has a cross section which corresponds to the outer diameter of the clamping sleeve 39, so that the valve spring 44 can be supported on the end face of the clamping sleeve 39. The pretensioning force of the valve spring 44 can be adjusted by the length of the clamping sleeve 39, which can also extend into the inlet opening 19, and also by the immersion depth of the hose connector 14 in the inlet opening 19, so that a certain opening pressure of the pressure valve 40 in the inlet opening 19 is adjustable. The pressure valves 31 and 40 are advantageously constructed identically, so that an inexpensive configuration is possible. Furthermore, the pressure valve 31 and the check valve 40 operate independently of one another.
Die Spannhülse 39 weist in ihrem den Ansaugraum 13 durchdringenden Bereich Öffnungsschlitze auf, so daß der über eine nicht dargestellte Kraftstoffleitung der Kraftstoff- Förderpumpe zugeführte Kraftstoff an dem Rückschlagventil 40 vorbeiströmen kann und über die Öffnungsschlitze der Spannhülse 39 dem Ansaugraum 13 zuführbar ist. Über diese schlitzförmige Öffnung kann auch der aus dem Druckraum 15 in den Bypasskanal 25 rückgeführte Kraftstoff in den Ansaugraum 13 zurückgeführt werden.The clamping sleeve 39 has in its area penetrating the suction space 13 opening slots, so that the over a fuel line (not shown) of the fuel feed pump can flow past the check valve 40 and can be fed to the suction chamber 13 via the opening slots of the clamping sleeve 39. The fuel returned from the pressure chamber 15 into the bypass channel 25 can also be returned to the intake chamber 13 via this slot-shaped opening.
In Fig. 4 ist eine alternative Ausfuhrungsform eines Rückschlagventils 50 gegenüber dem Rückschlagventil 40 in Fig. 3 dargestellt. Das Rückschlagventil 50 gemäß Fig. 4 ist als Baueinheit ausgebildet und weist einen Ringquerschnitt 51 auf, der an einer Schulter 52 der Einlaßöffnung 19 anliegt. Zur axialen Fixierung des Rückschlagventils 50 ist ein Anschlußelement 14 in die Einlaßöffnung 19 eingeschraubt oder eingepreßt. An dieses Anschlußelement 14 ist eine nicht dargestellte Kraftstoffleitung anschließbar. An den Ringquerschnitt 51 schließt sich ein topfförmig ausgebildetes Gehäuse 53 an, in dem eine Ventilfeder 54 gelagert ist, das ein Ventilschließglied 56 zur Anlage an dem Ringquerschnitt 51 bringt. Dabei ist der Ringquerschnitt 51 als Ventilsitz ausgebildet. Das Ventilschließglied 56 kann entgegen der Ventilfeder 54 durch den Kraftstoff ausgelenkt werden. Dieser strömt durch eine Öffnung 57 des RingquerSchnitts 51 in das Gehäuse 53 ein und über zumindest eine in einer Umfangswand 58 des Gehäuses 53 angeordneten Öffnung 59 in den Ansaugraum 13. Die Öffnungen 59 wirken analog zu den im Ventilschließglied 41 in der Umfangswand angeordneten Vertiefungen als Drossel, die den Förderstrom des Kraftstoffes bei steigender Drehzahl der Kraftstoff- Förderpumpe verringern kann. Bei dieser Ausfuhrungsform ist die Spannhülse 39 gegenüber der Ausführungsform in Fig. 3 verkürzt ausgebildet, so daß diese vollständig in dem Bypasskanal 25 eingesetzt sein kann.FIG. 4 shows an alternative embodiment of a check valve 50 compared to the check valve 40 in FIG. 3. The check valve 50 according to FIG. 4 is designed as a structural unit and has an annular cross section 51 which bears on a shoulder 52 of the inlet opening 19. For axially fixing the check valve 50, a connecting element 14 is screwed or pressed into the inlet opening 19. A fuel line, not shown, can be connected to this connecting element 14. A cup-shaped housing 53 adjoins the ring cross section 51, in which a valve spring 54 is mounted, which brings a valve closing member 56 into contact with the ring cross section 51. The ring cross section 51 is designed as a valve seat. The valve closing member 56 can be deflected by the fuel against the valve spring 54. This flows through an opening 57 of the ring cross section 51 into the housing 53 and via at least one opening 59 arranged in a circumferential wall 58 of the housing 53 into the suction space 13. The openings 59 act analogously to the depressions arranged in the valve closing member 41 in the circumferential wall as a throttle , which can reduce the flow rate of the fuel with increasing speed of the fuel delivery pump. In this embodiment, the clamping sleeve 39 is shortened compared to the embodiment in FIG. 3, so that it can be inserted completely in the bypass channel 25.
Alternativ kann auch vorgesehen sein, daß das Rückschlagventil 50 in einem Anschlußelement 14 integriert ist, so daß eine einfache Montage des Anschlußelementes 14 mit einem darin integrierten Rückschlagventil 50 gegeben sein kann. Desweiteren kann vorgesehen sein, daß das Ventilschließglied 56 als Kugel oder dergleichen ausgebildet ist.Alternatively, it can also be provided that the check valve 50 is integrated in a connection element 14, so that the connection element 14 can be easily assembled with a check valve 50 integrated therein. Furthermore, it can be provided that the valve closing member 56 is designed as a ball or the like.
Das Druckventil 31 und die Rückschlagventile 40, 50 können aus kraftstoff- und temperaturbeständigen Kunststoffen oder aus metallischen Werkstoffen oder in Kombination ausgebildet sein.The pressure valve 31 and the check valves 40, 50 can be made of fuel- and temperature-resistant plastics or of metallic materials or in combination.
Die erfindungsgemäße Kraftstoff-Förderpumpe arbeitet in folgender Weise: Im Betrieb der Brennkraftmaschine werden die Kraftstoff-Einspritzpumpe und die Kraftstoff-Förderpumpe proportional zur Drehzahl der Brennkraftmaschine angetrieben. Dies erfolgt bei der in den Fig. l bis 4 dargestellten Förderpumpe mittels eines an der Welle 5 von außen angreifenden nicht dargestellten mechanischen Übertragungselements. Durch die Rotation des ersten Zahnrades 7 und des mit diesem kämmenden zweiten Zahnrades 9 wird Kraftstoff aus dem Ansaugraum 13 entlang dem Förderkanal 17 in den Druckraum 15 gefördert. Dabei entsteht im Ansaugraum 13 ein Unterdruck, der ausreicht, um das Rückschlagventil 40, 50 zu öffnen und Kraftstoff über die Ansaugleitung aus dem Vorratstank anzusaugen. Der im Druckraum 15 aufgebaute Kraftstoffdruck bewirkt eine Kraftstoff-Förderung aus diesem über eine Fδrderleitung in den Saugraum der zu versorgenden Kraftstoff-Einspritzpumpe. Das Rückschlagventil 40, 50 wirkt als Drossel, die einen sanften Übergang der Kennlinie 60 gegenüber einem theoretischen Verlauf der Kennlinie 61 gemäß Fig. 5 aufweist, die auch einer Kennlinie entsprechen würde, wenn kein Rückschlagventil 40, 50 vorliegen würde. Die horizontal verlaufende Linie 62 ist durch den maximalen Förderstrom der Kraftstoff-Förderpumpe in Abhängigkeit des Öffnungsdruckes des Druckventils 31 in dem Bypasskanal 25 festgelegt.The fuel delivery pump according to the invention operates in the following manner: When the internal combustion engine is operating, the fuel injection pump and the fuel delivery pump are driven in proportion to the speed of the internal combustion engine. This takes place in the feed pump shown in FIGS. 1 to 4 by means of a mechanical transmission element, not shown, which acts on the shaft 5 from the outside. Due to the rotation of the first gear 7 and the second gear 9 meshing with it, fuel is conveyed from the intake chamber 13 along the delivery channel 17 into the pressure chamber 15. This creates a negative pressure in the intake space 13, which is sufficient to open the check valve 40, 50 and to draw fuel from the storage tank via the intake line. The fuel pressure built up in the pressure chamber 15 causes a fuel delivery from the latter via a delivery line into the suction chamber of the fuel injection pump to be supplied. The check valve 40, 50 acts as a throttle, which has a smooth transition of the characteristic curve 60 compared to a theoretical course of the characteristic curve 61 according to FIG. 5, which would also correspond to a characteristic curve if there were no check valve 40, 50. The horizontal line 62 is determined by the maximum delivery flow of the fuel delivery pump as a function of the opening pressure of the pressure valve 31 in the bypass channel 25.
Die Drosselwirkung beruht darauf, daß in dem Ventilschließglied 41 über den Umfang gleichmäßig verteilte Vertiefungen angeordnet sind, die ermöglichen, daß der Kraftstoff nach Abheben des Ventilschließgliedes 41 von dem Ventilsitz 42 über diese Öffnungen zum Ansaugraum 13 strömen kann. Bei der Ausfuhrungsform gemäß Fig. 4 strömt der Kraftstoff nach dem Abheben des Ventilschließgliedes 56 von dem Ventilsitz 51 über Öffnungen 59 des Gehäuses 53 zum Ansaugraum.The throttling effect is based on the fact that recesses are arranged in the valve closing member 41 which are uniformly distributed over the circumference, which enable the fuel to flow to the suction chamber 13 via these openings after lifting the valve closing member 41 from the valve seat 42. In the embodiment according to FIG. 4, the fuel flows after the valve closing member 56 has been lifted off the valve seat 51 via openings 59 in the housing 53 to the intake chamber.
Parallel dazu erfolgt die Steuerung des maximalen Kraftstoffdruckes im Druckraum 15 und somit der Fördermenge zur Kraftstoffeinspritzpumpe über den Bypasskanal 25, indem das Ventilschließglied 33 des darin eingesetzten Druckventils 31 ab einem bestimmten Druck im Druckraum 15 vom Ventilsitz 29 abhebt und so einen Abströmquerschnitt am Bypasskanal 25 öffnet, über den ein Teil der unter hohem Druck stehenden Kraftstoffmenge aus dem Druckraum 15 in den Ansaugraum 13 abströmt. Dadurch wird die aus der nicht dargestellten Kraftstoffleitung über das Anschlußelement 14 strömende Fördermenge verringert.In parallel, the control of the maximum fuel pressure in the pressure chamber 15 and thus the flow rate to the fuel injection pump via the bypass channel 25 takes place by the valve closing member 33 of the pressure valve 31 used therein lifting off from a certain pressure in the pressure chamber 15 from the valve seat 29 and thus opening an outflow cross section at the bypass channel 25 , via which a part of the fuel quantity under high pressure flows out of the pressure chamber 15 into the intake chamber 13. As a result, the flow rate flowing from the fuel line, not shown, via the connecting element 14 is reduced.
Durch das beim Stillstand der Kraftstoff-Förderpumpe sich in Schließstellung befindende Rückschlagventil 40, 50 verbleibt in dem Ansaugraum 13 als auch Druckraum 15 Kraftstoff, so daß beim Anlauf der Kraftstoff-Förderpumpe eine sofortige Förderung des Kraftstoffs zur Kraftstoff-Einspritzpumpe ermöglicht ist, ohne daß eine zusätzliche Entlüftung erforderlich ist. Dadurch kann der erforderliche Arbeitsdruck innerhalb kürzester Zeit aufgebaut werden. Beispielsweise kann bei Startdrehzahl innerhalb von 0,3 Sekunden ein Druck von 0,3 bar aufgebaut werden, wodurch ein sofortiger Start der Brennkraftmaschine gegeben sein kann. Gleichzeitig kann dadurch mit einer geringen Arbeitsleistung ein höherer Wirkungsgrad der Kraftstoff-Förderpumpe erzielt werden, wobei zusätzlich durch die Drosselwirkung der Rückschlagventile 40, 50 ein sanfter Übergang der zunächst stetig ansteigenden Kennlinie in einen sanften Übergang zum maximalen Förderstrom bewirkt, so daß die Förderpumpe eine verringerte Arbeitsleistung erbringen muß, die durch das schraffierte Feld 63 dargestellt ist. Durch die Anpassung der Fördermenge an die Bedarfsmenge durch die Drosselwirkung verringert sich die Differenz zwischen der geförderten Menge und der benötigten Menge. Due to the check valve 40, 50 which is in the closed position when the fuel delivery pump is at a standstill, fuel remains in the suction chamber 13 and also the pressure chamber 15, so that when the fuel delivery pump starts up, immediate delivery of the fuel to the fuel injection pump is made possible without the need for additional ventilation. This enables the required working pressure to be built up in the shortest possible time. For example, a pressure of 0.3 bar can be built up at the starting speed within 0.3 seconds, which means that the internal combustion engine can be started immediately. At the same time, a higher efficiency of the fuel delivery pump can be achieved with a low work output, and in addition, due to the throttling action of the check valves 40, 50, a smooth transition from the initially steadily increasing characteristic curve to a smooth transition to the maximum delivery flow causes a reduction in the delivery pump Must perform work, which is shown by hatched field 63. By adapting the delivery rate to the required amount through the throttling effect, the difference between the delivered amount and the required amount is reduced.

Claims

Ansprüche Expectations
1. Kraftstoff-Förderpumpe für eine Kraftstoff-Einspritzpumpe für Brennkraftmaschinen, mit einem in einer Pumpkammer (3) rotierend angetriebenen Paar miteinander kämmender Zahnräder (7, 9) oder sonstiger rotierender Verdrängerelemente, die Kraftstoff aus einem mit einem Vorratstank verbundenen Ansaugraum (13) entlang einem zwischen der Stirnfläche der Zahnräder (7, 9) und der Umfangswand der Pumpkammer (3) gebildeten Förderkanal (17) in einen, mit der Kraftstoff-Einspritzpumpe verbundenen Druckraum (15) fördern und mit einem in einem Gehäuse (1) der Kraftstoff-Förderpumpe integrierten und den Ansaugraum (13) mit dem Druckraum (15) verbindenden Bypasskanal (25) , der mittels eines darin angeordneten Druckventils (31) aufsteuerbar ist, dadurch gekennzeichnet, daß der Ansaugraum (13) mit einem entgegen der Kraftstoff-Förderrichtung wirkenden Rückschlagventil (40, 50) verschließbar ist.1.Fuel feed pump for a fuel injection pump for internal combustion engines, with a pair of meshing gears (7, 9) or other rotating displacement elements driven in rotation in a pump chamber (3), or other rotating displacement elements, which take fuel from an intake chamber (13) connected to a storage tank convey a delivery channel (17) formed between the end face of the gearwheels (7, 9) and the peripheral wall of the pump chamber (3) into a pressure chamber (15) connected to the fuel injection pump and with one in a housing (1) of the fuel Delivery pump integrated and connecting the suction chamber (13) with the pressure chamber (15) bypass channel (25), which can be opened by means of a pressure valve (31) arranged therein, characterized in that the suction chamber (13) with a check valve acting counter to the fuel delivery direction (40, 50) can be closed.
2. Kraftstoff-Förderpumpe nach Anspruch 1, dadurch gekennzeichnet, daß das Rückschlagventil (40, 50) in einer zum Ansaugraum (13) führenden Öffnung (19) des Gehäuses (1) anordenbar ist. 2. Fuel feed pump according to claim 1, characterized in that the check valve (40, 50) in a leading to the suction chamber (13) opening (19) of the housing (1) can be arranged.
3. Kraftstoff-Förderpumpe nach Anspruch l oder 2, dadurch gekennzeichnet, daß das Rückschlagventil (40, 50) als Drosselventil ausgebildet ist.3. Fuel feed pump according to claim l or 2, characterized in that the check valve (40, 50) is designed as a throttle valve.
4. Kraftstoff-Förderpumpe nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß das Rückschlagventil (40) in der Öffnung (19) axial geführt ist und gegen eine in der Öffnung (19) angeordnete Ventilfeder (44) in Kraftstoffrichtung offenbar ist.4. Fuel feed pump according to one of the preceding claims, characterized in that the check valve (40) is axially guided in the opening (19) and against a valve spring (44) arranged in the opening (19) in the fuel direction is evident.
5. Kraftstoff-Förderpumpe nach Anspruch 4, dadurch gekennzeichnet, daß in die Öffnung (19) ein Ventilsitz (42) und den Querschnitt verringerndes Anschlußelement (14) einsetzbar ist, an der ein Ventilschließglied (41) des Rückschlagventils (40) mit einer Dichtfläche (43) mittels der Ventilfeder (44) zur Anlage bringbar ist.5. Fuel feed pump according to claim 4, characterized in that in the opening (19) a valve seat (42) and the cross-section-reducing connecting element (14) can be used, on which a valve closing member (41) of the check valve (40) with a sealing surface (43) can be brought into contact with the valve spring (44).
6. Kraftstoff-Förderpumpe nach Anspruch 4 oder 5, dadurch gekennzeichnet, daß die Ventilfeder (44) sich an einem dem Ventilschließglied (41) gegenüberliegenden in das saugraumseitige Ende des Bypassventils (25) eingesetzten Spannhülse (39) abstützt.6. Fuel feed pump according to claim 4 or 5, characterized in that the valve spring (44) is supported on a valve closing member (41) opposite in the suction chamber end of the bypass valve (25) inserted clamping sleeve (39).
7. Kraftstoff-Förderpumpe nach Anspruch 6, dadurch gekennzeichnet, daß die Spannhülse (39) an die Öffnung (19) angrenzt oder zumindest teilweise in die Öffnung (19) eingreift und in einem den Ansaugraum (13) durchdringenden Bereich geschlitzt ausgebildet ist.7. Fuel feed pump according to claim 6, characterized in that the clamping sleeve (39) adjoins the opening (19) or at least partially engages in the opening (19) and is slotted in an area penetrating the suction chamber (13).
8. Kraftstoff-Förderpumpe nach Anspruch 5, dadurch gekennzeichnet, daß das Anschlußelement (14) als Schlauchstutzen ausgebildet ist, der in die Öffnung (19) des Gehäuses (1) einsetzbar, vorzugsweise mit einem Schnellverschluß befestigbar ist. 8. Fuel feed pump according to claim 5, characterized in that the connecting element (14) is designed as a hose connector which can be inserted into the opening (19) of the housing (1), preferably fastened with a quick-release fastener.
9. Kraftstoff-Förderpumpe nach einem der Ansprüche l bis 3, dadurch gekennzeichnet, daß das Rückschlagventil (50) als Baueinheit in die Öffnung (19) einsetzbar ist und mit einem Anschlußelement (14) axial zur Öffnung (19) positionierbar ist.9. Fuel feed pump according to one of claims l to 3, characterized in that the check valve (50) can be used as a structural unit in the opening (19) and can be positioned axially to the opening (19) with a connecting element (14).
10. Kraftstoff-Förderpumpe nach Anspruch 9, dadurch gekennzeichnet, daß das Rückschlagventil (50) eine in einem Gehäuse (53) angeordnete Ventilfeder (54) aufweist, die ein Ventilschließglied (56) an einem als Ventilsitz ausgebildeten Ringquerschnitt (51) zur Anlage bringt.10. Fuel feed pump according to claim 9, characterized in that the check valve (50) has a valve spring (54) arranged in a housing (53), which brings a valve closing member (56) to an annular cross-section designed as a valve seat (51) to the system .
11. Kraftstoff-Förderpumpe nach Anspruch 9 oder 10, dadurch gekennzeichnet, daß in einer Umfangswand (58) des Gehäuses (53) zumindest eine Öffnung (59) vorgesehen ist.11. Fuel feed pump according to claim 9 or 10, characterized in that at least one opening (59) is provided in a peripheral wall (58) of the housing (53).
12. Kraftstoff-Förderpumpe nach einem der Ansprüche 9 bis 11, dadurch gekennzeichnet, daß das als Baueinheit ausgebildete Rückschlagventil (50) im Anschlußelement (14) integriert ist. 12. Fuel feed pump according to one of claims 9 to 11, characterized in that the check valve designed as a structural unit (50) is integrated in the connecting element (14).
EP97915286A 1996-06-26 1997-02-13 Fuel supply pump for a fuel injection pump for internal combustion engines Expired - Lifetime EP0846224B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19625565A DE19625565C2 (en) 1996-06-26 1996-06-26 Fuel feed pump for a fuel injection pump for internal combustion engines
DE19625565 1996-06-26
PCT/DE1997/000273 WO1997049910A1 (en) 1996-06-26 1997-02-13 Fuel supply pump for a fuel injection pump for internal combustion engines

Publications (2)

Publication Number Publication Date
EP0846224A1 true EP0846224A1 (en) 1998-06-10
EP0846224B1 EP0846224B1 (en) 2000-12-27

Family

ID=7798073

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97915286A Expired - Lifetime EP0846224B1 (en) 1996-06-26 1997-02-13 Fuel supply pump for a fuel injection pump for internal combustion engines

Country Status (5)

Country Link
US (1) US6099263A (en)
EP (1) EP0846224B1 (en)
CZ (1) CZ290647B6 (en)
DE (2) DE19625565C2 (en)
WO (1) WO1997049910A1 (en)

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Also Published As

Publication number Publication date
US6099263A (en) 2000-08-08
DE59702810D1 (en) 2001-02-01
WO1997049910A1 (en) 1997-12-31
CZ54898A3 (en) 1998-10-14
EP0846224B1 (en) 2000-12-27
CZ290647B6 (en) 2002-09-11
DE19625565A1 (en) 1998-01-08
DE19625565C2 (en) 1998-07-23

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