EP0319707B1 - Fuel injection pump for internal-combustion engines, particularly for diesel engines - Google Patents

Fuel injection pump for internal-combustion engines, particularly for diesel engines Download PDF

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Publication number
EP0319707B1
EP0319707B1 EP19880118279 EP88118279A EP0319707B1 EP 0319707 B1 EP0319707 B1 EP 0319707B1 EP 19880118279 EP19880118279 EP 19880118279 EP 88118279 A EP88118279 A EP 88118279A EP 0319707 B1 EP0319707 B1 EP 0319707B1
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EP
European Patent Office
Prior art keywords
damping
plunger
pump
interior space
fuel injection
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP19880118279
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German (de)
French (fr)
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EP0319707A3 (en
EP0319707A2 (en
Inventor
Karl Konrath
Claus Koester
Karl Zibold
Manfred Schwarz
Karl-Friedrich Rüsseler
Klaus Dipl.-Ing. Krieger
Roland Dipl.-Ing. Kupzik
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Robert Bosch GmbH
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Robert Bosch GmbH
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Publication of EP0319707A2 publication Critical patent/EP0319707A2/en
Publication of EP0319707A3 publication Critical patent/EP0319707A3/en
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Publication of EP0319707B1 publication Critical patent/EP0319707B1/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D1/00—Controlling fuel-injection pumps, e.g. of high pressure injection type
    • F02D1/02—Controlling fuel-injection pumps, e.g. of high pressure injection type not restricted to adjustment of injection timing, e.g. varying amount of fuel delivered
    • F02D1/04—Controlling fuel-injection pumps, e.g. of high pressure injection type not restricted to adjustment of injection timing, e.g. varying amount of fuel delivered by mechanical means dependent on engine speed, e.g. using centrifugal governors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B3/00—Engines characterised by air compression and subsequent fuel addition
    • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition

Definitions

  • the invention relates to a fuel injection pump for internal combustion engines, in particular diesel internal combustion engines, of the type defined in the preamble of claim 1.
  • a major disadvantage of passenger cars equipped with diesel engines is the vehicle jerking at low engine speeds, which, in addition to full-load and part-load jerking, mainly occurs due to the acceleration and deceleration process triggered by rapid accelerator pedal actuation.
  • diesel internal combustion engines with fuel injection pumps are additionally provided with damping devices which, in the case of rapid “accelerating” or “taking away gas”, only have a delayed effect on the corresponding changes in the fuel injection quantities by the fuel injection pump.
  • the hydraulic damping device is arranged between the speed adjustment lever of the fuel injection pump and the vehicle body coupled to the accelerator pedal, the damping cylinder being connected to the body and the damping piston via a piston rod to the speed adjustment lever.
  • a throttle is arranged in a longitudinal axial bore of the damping piston, which connects two damping chambers located on opposite sides of the piston.
  • the speed adjustment lever is connected in a rotationally fixed manner to an adjustment shaft which can be pivoted in the pump housing of the fuel injection pump and to the end of which projects rigidly into the pump interior.
  • the control spring connected to the control lever acts on the lever.
  • the accelerator pedal engages the speed adjustment lever via compression springs.
  • the speed adjustment lever When the accelerator pedal is pressed quickly, the speed adjustment lever follows its movement only with a delay because it is supported on the body by the damping device.
  • the internal combustion engine which is suspended from the body by means of flexible buffers, tilts to one side about its longitudinal axis.
  • the speed adjustment lever is supported on the body via the damping device and is pivoted in the direction of reducing the fuel injection quantity.
  • the internal combustion engine tilts to the other side with a rapidly decreasing torque, the speed adjustment lever being displaced by the damping device in the direction of a larger amount of fuel.
  • the damping device thus has, on the one hand, a retarding effect when accelerating and, on the other hand, a differentiating effect when changing the amount of fuel due to the deflection of the internal combustion engine.
  • the damping device acts accordingly.
  • the jerking of the vehicle is actively damped by the negative feedback of the engine movement and the metered amount of fuel.
  • the damping effect is always the same when “accelerating” and “accelerating” and does not therefore achieve optimal suppression of vehicle jerking in all cases.
  • the fuel injection pump according to the invention with the characterizing features of claim 1 has the advantage that the acceleration and deceleration damping can be achieved individually and without dead paths in the required range.
  • the two throttles enable the acceleration and deceleration damping to be set separately.
  • the delay times can be determined independently of one another by the pretensioned trailing spring or return spring and by the cross section of the throttle bores, thus ensuring an optimal setting that largely eliminates the jerking of the vehicle.
  • An advantageous embodiment of the invention results when unthrottled flow paths between the damping chamber and pump interior are connected in parallel with the throttles in such a way that they are only released in the areas of the displacement path of the damping piston in which idle paths of the speed adjustment lever occur, i.e. in the areas of the speed adjustment lever pivoting in which no injection is yet taking place. In this way, the response behavior of the fuel injection pump with respect to avoiding vehicle jerking is further improved.
  • a particularly advantageous embodiment of the invention results from claim 7.
  • the pressure valve opens and opens a further unthrottled flow path between the damping chamber and pump interior.
  • the damping device is automatically ineffective at higher speeds, because in this speed range due to the high kinetic energy of the flywheels, a vehicle jerk does not occur and damping is not required.
  • the invention is explained in more detail in the following description with reference to an embodiment shown in the drawing.
  • the drawing shows a detail of a fuel injection pump for a diesel internal combustion engine in a schematic representation.
  • the known fuel injection pump of the distributor type (cf. DE-OS 3427224, FIG. 2), which is shown only partially and schematically in FIG. 1, has a pump housing, indicated by 10, which encloses a pump interior 11.
  • the pump interior 11 is filled with fuel by means of a feed pump 12.
  • the pump interior 11 is under a pressure of 6-8 bar.
  • a pump piston 13 is set into a reciprocating and at the same time rotating movement via a cam drive 14.
  • the pump piston 13 slides in a cylinder sleeve 15, which is seated in the pump housing 10, and delimits a pump work chamber 16 therewith.
  • the pump work chamber 16 is via a longitudinal groove 17 in the end section of the pump piston 13, an inlet opening 18 in the cylinder sleeve 15 and a channel 19 in the pump housing 10 connectable to the pump interior 11.
  • the pump working space 16 is connected via a pressure valve 20 and a channel 21 to an annular channel 22 in the pump piston 13.
  • a distribution groove 23 branches off in the pump piston 13 and cooperates with outlet channels 24, which are distributed over the circumference of the cylinder liner 15 and of which only one is shown.
  • Each outlet channel 24 is connected to a connection opening 25 for an injection nozzle.
  • an axial channel 26 leads to a transverse channel 27 in the pump piston 13.
  • the transverse channel 27 works together with a quantity adjusting element 28, which is axially displaceable on the pump piston section projecting into the pump interior 11.
  • the pump piston 13 delivers high-pressure fuel from the pump work space 16 via the pressure valve 20, the channel 21, the annular channel 22 and the distributor groove 23 into one of the outlet channels 24.
  • the pump work space 16 is connected to the pump interior 11 and is relieved.
  • the high-pressure delivery to the connection openings 25 is abruptly stopped.
  • the relative position of the quantity adjusting member 28 relative to the pump piston 13 thus determines the amount of fuel that is to be injected via the outlet channels 24.
  • a spherical arm of a two-armed control lever 29 engages thereon, which is mounted on a pin 30 fixed to the housing
  • Control spring 31 on a speed adjustment lever 32 which can be pivoted arbitrarily in the direction of arrow 33 via an accelerator pedal, not shown.
  • a return spring 34 serves to reset the speed adjustment lever 32 if the actuating force on the accelerator pedal is lost.
  • the two-armed speed adjustment lever 32 can be rotated about a pivot axis 35 fixed on the pump housing 10.
  • the coupling between the speed adjustment lever 32 and the control spring 31 takes place via a preloaded drag spring 36 which is supported on the one hand on a lever arm of a damper lever 37 and on the other hand on the arm of the speed adjustment lever 32 remote from the return spring 34.
  • the pretensioned drag spring 36 presses the lever arm of the speed adjustment lever 32 against a stop 38 which is arranged on the lever arm of the damper lever 37 remote from the drag spring 36.
  • the damper lever 37 itself is pivotally arranged on the pivot axis 35 of the speed adjustment lever 32.
  • the damper lever 37 is part of a damping device 40 which serves to improve the smooth running of the internal combustion engine when the speed adjustment lever 32 is actuated quickly and eliminates the so-called vehicle jerking when the accelerator pedal is depressed or released quickly.
  • the hydraulic damping device 40 is arranged in the pump interior 11 and comprises a damper housing 41 with a longitudinal bore 42 which is closed at both ends, a guide sleeve 43 which can be displaced in the longitudinal bore 42 and a damping piston 44 which slides in the guide sleeve 43.
  • Damper housing 41 and guide sleeve 43 form in a known manner, a damping cylinder which, together with the one end face of the damping piston 44, delimits a damping chamber 45.
  • the damping chamber 45 is on the one hand via a first check valve 46 and a first throttle 47, both of which are arranged in the damping piston 44, and on the other hand via a second throttle 48 and a second check valve 49, both of which are arranged in the damper housing 41, with the pump interior 11 in Connection.
  • the connection between the outlet of the first throttle 47 and the pump interior 11 is ensured by a first radial bore 60 in the guide sleeve 43 and a first radial through opening 61 in the damper housing 41.
  • the diameter of the through opening 61 is that of the Radial bore 60 dimensioned very large, so that even with a sliding movement of the guide sleeve 43 relative to the damper housing 41, the through hole 61 always releases the radial bore 60 to the pump interior 11.
  • the two check valves 46, 49 are arranged such that the blocking direction of the first check valve 46 towards the pump interior 11 and that of the second check valve 49 towards the damping chamber 45 are directed.
  • the lever arm of the damper lever 37 carrying the stop 38 is articulated to the damping piston 44, while the lifting arm of the damper lever 37 carrying the pretensioned drag spring 36 is coupled to the control spring 31.
  • the guide sleeve 43 delimits on one end face a control chamber 50 which is connected to the pump interior 11 via a radial inlet duct 51.
  • the other end of the guide sleeve 43 is covered with an end plate 52, which also serves as a guide for a compression spring 53.
  • Guide sleeve 43 and end plate 52 delimit a relief chamber 54 which receives the compression spring 53 and is connected via an outlet channel 55 to a fuel return line, which is indicated by the arrow 56.
  • the compression spring 53 is supported on a stop plate 57, the spatial position of which in the relief chamber 54 is adjustable by means of an adjusting pin 58 which can be screwed into the damper housing 41. The prestressing of the compression spring 53 can be adjusted by turning the adjusting pin 58 more or less.
  • the first flow path 67 is formed by a bypass bore 62 bypassing the first throttle 47 in the damping piston 44, the first radial bore 60 forming a control opening in the guide sleeve 43 and the first through opening 61 in the damper housing 41 corresponding thereto.
  • the diameter of the first radial bore 60 is chosen so large that, depending on the position of the damping piston 44 relative to the guide sleeve 43, only the mouth of the first throttle 47 or additionally the mouth of the bypass bore 62 from the guide sleeve 43 to the pump interior 11 are released.
  • the second unthrottled flow path 68 between the damping chamber 45 and the pump interior 11 is provided by an annular groove 63 in the damping chamber 45, by an axial groove 64 in constant communication with the annular groove 63 on the circumference of the damping piston 44, a second radial bore 65 in the guide sleeve 43 and a second through opening 66 is formed in the damper housing 41.
  • the diameter of the passage opening 66 is chosen so large that the second radial bore 65 in the guide sleeve 43 to the pump interior 11 is released over the entire displacement range of the guide sleeve 43.
  • the annular groove 63 in the damping chamber 45 is designed such that it is closed off from the rest of the damping chamber 45 after a certain displacement path of the damping piston 44, which depends on the relative position of the damping piston 44 and guide sleeve 43.
  • the axial groove 64 in the damping piston 44 has a length such that the annular groove 63 remains connected to the second radial bore 65 in the guide sleeve 43 over the entire displacement path of the damping piston 44.
  • the damping piston 44 requires a more or less large displacement path in order to close the annular groove 63 with respect to the damping chamber 45 - and thus to block the flow path 68 - or to release it again - and thus to open the flow path 68.
  • This flow path 68 is thus effective in both directions of the displacement movement of the damping piston 44, while the first unthrottled flow path 67, as a result of the first check valve 46 located in the flow path 67, only moves the damping piston 44 to the left in the drawing, i.e. when the speed adjustment lever 32 is adjusted in Direction of smaller fuel flow rates, can take effect.
  • Vehicle jerking is mainly noticeable at low engine speeds and is largely suppressed here by the damping device 40 described above.
  • the damping device 40 In the higher speed range, due to the high kinetic energy of the flywheels, vehicle jerking is no longer noticeable, so that the damping device 40 is rather superfluous and tends to have disadvantages for driving behavior. For this reason, the damping devices 40 are switched off at higher speeds, so that their damping effect is zero.
  • a third unthrottled flow way 69 provided that connects the damping chamber 45 directly to the pump interior 11 at higher speeds and thus shorts the damping device 40.
  • the third unthrottled flow path 69 is locked below a certain speed.
  • the flow path 69 is locked and released by means of a pressure valve 70, which is designed here as a slide valve.
  • a blind hole 71 is made in the damper housing 41, which is connected to the relief space 54 near the bottom of the bag via a relief bore 72.
  • a control piston 73 slides in the blind bore 71, which is acted upon by the pressure in the pump interior 11 on its end face facing the mouth of the blind bore 71 and is supported with its other end face by a compression spring 74 on the bag base.
  • the third flow path 69 is formed by two bores 75, 76 in the damper housing 41, which are connected on the one hand to the pump interior 11 and on the other hand to the damping chamber 45 and open diametrically in the blind bore 71 in a cross-sectional plane. With the two mouths of the bores 75, 76, a control groove 77 cooperates on the control piston 73, which, depending on the displacement position of the control piston 73, releases or blocks the passage from the bore 76 to the bore 75.
  • the pressure valve 70 is set such that when a certain pressure in the pump interior 11 is exceeded, the control piston 73 is displaced so far against the force of the compression spring 74 that the bores 75, 76 are connected to one another and thus the damping chamber 45 the pump interior 11 is connected.
  • Such an increase in pressure in the pump interior 11 takes place only at higher speeds of the internal combustion engine and thus of the feed pump 12.

Description

Stand der TechnikState of the art

Die Erfindung betrifft eine Kraftstoffeinspritzpumpe für Brennkraftmaschinen, insbesondere Dieselbrennkraftmaschinen, der im Oberbegriff des Anspruchs 1 definierten Gattung.The invention relates to a fuel injection pump for internal combustion engines, in particular diesel internal combustion engines, of the type defined in the preamble of claim 1.

Ein wesentlicher Nachteil von mit Dieselbrennkraftmaschinen ausgerüsteten Personenkraftwagen ist das Fahrzeugruckeln bei niedrigen Drehzahlen, das neben dem Vollast- und Teillastruckeln hauptsächlich durch den Beschleunigungs- und Verzögerungsvorgang, ausgelöst durch rasche Fahrpedalbetätigung, auftritt. Um dieses Fahrzeugruckeln weitgehend auszuschalten, sind Dieselbrennkraftmaschinen mit Kraftstoffeinspritzpumpen zusätzlich mit Dämpfungsvorrichtungen versehen, die beim schnellen "Gasgeben" oder "Gaswegnehmen" die entsprechenden Änderungen der Kraftstoffeinspritzmengen durch die Kraftstoffeinspritzpumpe nur verzögert wirksam werden lassen.A major disadvantage of passenger cars equipped with diesel engines is the vehicle jerking at low engine speeds, which, in addition to full-load and part-load jerking, mainly occurs due to the acceleration and deceleration process triggered by rapid accelerator pedal actuation. In order to largely eliminate this jerking of the vehicle, diesel internal combustion engines with fuel injection pumps are additionally provided with damping devices which, in the case of rapid “accelerating” or “taking away gas”, only have a delayed effect on the corresponding changes in the fuel injection quantities by the fuel injection pump.

Bei einer bekannten Kraftstoffeinspritzpumpe der eingangs genannten Art (DE-OS 3427224) ist die hydraulische Dämpfungsvorrichtung zwischen dem mit dem Fahrpedal gekoppelten Drehzahlverstellhebel der Kraftstoffeinspritzpumpe und der Fahrzeugkarosserie angeordnet, wobei der Dämpfungszylinder mit der Karosserie und der Dämpfungskolben über eine Kolbenstange mit dem Drehzahlverstellhebel verbunden ist. In einer längsdurchgehenden Axialbohrung des Dämpfungskolbens ist eine Drossel angeordnet, die zwei auf gegenüberliegenden Kolbenseiten befindliche Dämpfungskammern miteinander verbindet. Der Drehzahlverstellhebel ist mit einer im Pumpengehäuse der Kraftstoffeinspritzpumpe schwenkbaren Verstellwelle drehfest verbunden, an deren in den Pumpeninnenraum hineinragendem Ende ein Hebel starr befestigt ist. An dem Hebel greift die mit dem Regelhebel verbundene Regelfeder an. Das Fahrpedal greift über Druckfedern an dem Drehzahlverstellhebel an. Beim raschen Betätigen des Fahrpedals folgt der Drehzahlverstellhebel dessen Bewegung nur verzögert, da er sich über die Dämpfungsvorrichtung an der Karosserie abstützt. Bei zunehmendem Drehmoment neigt sich die mittels nachgiebiger Puffer an der Karosserie aufgehängte Brennkraftmaschine um ihre Längsachse zu der einen Seite hin. Dabei stützt sich der Drehzahlverstellhebel über die Dämpfungsvorrichtung an der Karosserie ab und wird in Richtung zum Reduzieren der Kraftstoffeinspritzmenge verschwenkt. Umgekehrt neigt sich die Brennkraftmaschine bei schnell abnehmendem Drehmoment zur anderen Seite, wobei der Drehzahlverstellhebel von der Dämpfungsvorrichtung in Richtung größerer Kraftstoffmenge verschoben wird. Die Dämpfungsvorrichtung hat damit zum einen eine verzögernde Wirkung beim Gasgeben und zum anderen eine differenzierende Wirkung bei der Kraftstoffmengenänderung durch die Auslenkung der Brennkraftmaschine. In umgekehrter Richtung, also beim "Gaswegnehmen", wirkt die Dämpfungsvorrichtung entsprechend. Mit der Gegenkopplung der Brennkraftmaschinenbewegung und der zugemessenen Kraftstoffmenge wird das Ruckeln des Fahrzeugs aktiv gedämpft. Die Dämpfungswirkung ist jedoch beim "Gasgeben" und "Gaswegnehmen" immergleich groß und erreicht damit nicht in allen Fällen eine optimale Unterdrückung des Fahrzeugruckelns.In a known fuel injection pump of the type mentioned (DE-OS 3427224), the hydraulic damping device is arranged between the speed adjustment lever of the fuel injection pump and the vehicle body coupled to the accelerator pedal, the damping cylinder being connected to the body and the damping piston via a piston rod to the speed adjustment lever. A throttle is arranged in a longitudinal axial bore of the damping piston, which connects two damping chambers located on opposite sides of the piston. The speed adjustment lever is connected in a rotationally fixed manner to an adjustment shaft which can be pivoted in the pump housing of the fuel injection pump and to the end of which projects rigidly into the pump interior. The control spring connected to the control lever acts on the lever. The accelerator pedal engages the speed adjustment lever via compression springs. When the accelerator pedal is pressed quickly, the speed adjustment lever follows its movement only with a delay because it is supported on the body by the damping device. As the torque increases, the internal combustion engine, which is suspended from the body by means of flexible buffers, tilts to one side about its longitudinal axis. The speed adjustment lever is supported on the body via the damping device and is pivoted in the direction of reducing the fuel injection quantity. Conversely, the internal combustion engine tilts to the other side with a rapidly decreasing torque, the speed adjustment lever being displaced by the damping device in the direction of a larger amount of fuel. The damping device thus has, on the one hand, a retarding effect when accelerating and, on the other hand, a differentiating effect when changing the amount of fuel due to the deflection of the internal combustion engine. In the opposite direction, ie when "accelerating", the damping device acts accordingly. The jerking of the vehicle is actively damped by the negative feedback of the engine movement and the metered amount of fuel. However, the damping effect is always the same when "accelerating" and "accelerating" and does not therefore achieve optimal suppression of vehicle jerking in all cases.

Vorteile der ErfindungAdvantages of the invention

Die erfindungsgemäße Kraftstoffeinspritzpumpe mit den kennzeichnenden Merkmalen des Anspruchs 1 hat den Vorteil, daß die Beschleunigungs- und Verzögerungsdämpfung individuell und ohne Totwege in dem erforderlichen Bereich erreicht werden kann. Die beiden Drosseln ermöglichen die separate Einstellung der Beschleunigungs- und Verzögerungsdämpfung. Für beide Dämpfungsrichtungen können durch die vorgespannte Schleppfeder bzw. Rückstellfeder sowie durch den Querschnitt der Drosselbohrungen die Verzögerungszeiten unabhängig voneinander bestimmt und damit eine das Fahrzeugruckeln weitgehend beseitigende optimale Einstellung gewährleistet werden.The fuel injection pump according to the invention with the characterizing features of claim 1 has the advantage that the acceleration and deceleration damping can be achieved individually and without dead paths in the required range. The two throttles enable the acceleration and deceleration damping to be set separately. For both damping directions, the delay times can be determined independently of one another by the pretensioned trailing spring or return spring and by the cross section of the throttle bores, thus ensuring an optimal setting that largely eliminates the jerking of the vehicle.

Durch die in den weiteren Ansprüchen aufgeführten Maßnahmen sind vorteilhafte Weiterbildungen und Verbesserungen der im Anspruch 1 angegebenen Kraftstoffeinspritzpumpe möglich.Advantageous further developments and improvements of the fuel injection pump specified in claim 1 are possible through the measures listed in the further claims.

Eine vorteilhafte Ausführungsform der Erfindung ergibt sich, wenn ungedrosselte Strömungswege zwischen Dämpfungskammer und Pumpeninnenraum den Drosseln derart parallel geschaltet werden, daß sie nur in den Bereichen des Verschiebeweges des Dämpfungskolbens freigegeben sind, in welchen Leerwege des Drehzahlverstellhebels auftreten, d.h. in den Bereichen der Drehzahlverstellhebel-Verschwenkung, in welchen noch keine Einspritzung stattfindet Auf diese Weise wird das Ansprechverhalten der Kraftstoffeinspritzpumpe bezüglich der Vermeidung des Fahrzeugruckelns noch weiter verbessert.An advantageous embodiment of the invention results when unthrottled flow paths between the damping chamber and pump interior are connected in parallel with the throttles in such a way that they are only released in the areas of the displacement path of the damping piston in which idle paths of the speed adjustment lever occur, i.e. in the areas of the speed adjustment lever pivoting in which no injection is yet taking place. In this way, the response behavior of the fuel injection pump with respect to avoiding vehicle jerking is further improved.

Eine besonders vorteilhafte Ausführungsform der Erfindung ergibt sich aus Anspruch 7. Bei höheren Drehzahlen der Brennkraftmaschine und des damit verbundenen Druckanstiegs im Pumpeninnenraum öffnet das Druckventil und gibt einen weiteren ungedrosselten Strömungsweg zwischen Dämpfungskammer und Pumpeninnenraum frei. Dadurch wird die Dämpfungsvorrichtung bei höheren Drehzahlen automatisch wirkungslos geschaltet, da in diesem Drehzahl bereich wegen der hohen kinetischen Energie der Schwungmassen ein Fahrzeugruckeln nicht auftritt und eine Dämpfung nicht erforderlich ist.A particularly advantageous embodiment of the invention results from claim 7. At higher speeds of the internal combustion engine and the associated pressure rise in the pump interior, the pressure valve opens and opens a further unthrottled flow path between the damping chamber and pump interior. As a result, the damping device is automatically ineffective at higher speeds, because in this speed range due to the high kinetic energy of the flywheels, a vehicle jerk does not occur and damping is not required.

Zeichnungdrawing

Die Erfindung ist anhand eines in der Zeichnung dargestellten Ausführungsbeispiels in der nachfolgenden Beschreibung näher erläutert. Dabei zeigt die Zeichnung ausschnittweise eine Kraftstoffeinspritzpumpe für eine Dieselbrennkraftmaschine in schematischer Darstellung.The invention is explained in more detail in the following description with reference to an embodiment shown in the drawing. The drawing shows a detail of a fuel injection pump for a diesel internal combustion engine in a schematic representation.

Beschreibung des AusführungsbeispielsDescription of the embodiment

Die in Fig. 1 nur ausschnittweise und schematisch dargestellte an sich bekannte Kraftstoffeinspritzpumpe der Verteilerbauart (vergl. DE-OS 3427224, Fig. 2) weist ein mit 10 angedeutetes Pumpengehäuse auf, das einen Pumpeninnenraum 11 umschließt. Der Pumpeninnenraum 11 wird mittels einer Förderpumpe 12 mit Kraftstoff gefüllt. Der Pumpeninnenraum 11 steht dabei unter einem Druck von 6-8 bar. Synchron mit der Förderpumpe 12 wird ein Pumpenkolben 13 über einen Nockentrieb 14 in eine hin- und hergehende und zugleich rotierende Bewegung versetzt. Der Pumpenkolben 13 gleitet in einer Zylinderbuchse 15, die im Pumpengehäuse 10 sitzt, und begrenzt mit dieser einen Pumpenarbeitsraum 16. Der Pumpenarbeitsraum 16 ist über eine Längsnut 17 im Endabschnitt des Pumpenkolbens 13, eine Einlaßöffnung 18 in der Zylinderbuchse 15 und einen Kanal 19 im Pumpengehäuse 10 mit dem Pumpeninnenraum 11 verbindbar. Der Pumpenarbeitsraum 16 ist über ein Druckventil 20 und einen Kanal 21 mit einem Ringkanal 22 im Pumpenkolben 13 verbunden. Vom Ringkanal 22 zweigt eine im Pumpenkolben 13 verlaufende Verteilemut 23 ab, die mit Auslaßkanälen 24 zusammenarbeitet, die über den Umfang der Zylinderbuchse 15 verteilt sind und von denen nur einer gezeichnet ist. Jeder Auslaßkanal 24 ist mit einer Anschlußöffnung 25 für eine Einspritzdüse verbunden. Von dem Pumpenarbeitsraum 16 führt im Pumpenkolben 13 ein Axialkanal 26 zu einem Querkanal 27. Der Querkanal 27 arbeitet mit einem Mengenverstellorgan 28 zusammen, das auf den in den Pumpeninnenraum 11 hineinragenden Pumpenkolbenabschnitt axial verschieblich sitzt. Solange der Querkanal 27 von dem Mengenverstellorgan 28 abgedeckt ist, fördert der Pumpenkolben 13 unter Hochdruck stehenden Kraftstoff aus dem Pumpenarbeitsraum 16 über das Druckventil 20, den Kanal 21, den Ringkanal 22 und die Verteilernut 23 in einen der Auslaßkanäle 24. In dem Moment, wo der Querkanal 27 aus dem Mengenverstellorgan 28 austritt, wird der Pumpenarbeitsraum 16 mit dem Pumpeninnenraum 11 verbunden und entlastet. Die Hochdruckförderung zu den Anschlußöffnungen 25 wird schlagartig abgebrochen. Damit bestimmt die relative Lage des Mengenverstellorgans 28 zu dem Pumpenkolben 13 die über die Auslaßkanäle 24 zur Einspritzung gelangende Kraftstoffmenge.The known fuel injection pump of the distributor type (cf. DE-OS 3427224, FIG. 2), which is shown only partially and schematically in FIG. 1, has a pump housing, indicated by 10, which encloses a pump interior 11. The pump interior 11 is filled with fuel by means of a feed pump 12. The pump interior 11 is under a pressure of 6-8 bar. In synchronism with the feed pump 12, a pump piston 13 is set into a reciprocating and at the same time rotating movement via a cam drive 14. The pump piston 13 slides in a cylinder sleeve 15, which is seated in the pump housing 10, and delimits a pump work chamber 16 therewith. The pump work chamber 16 is via a longitudinal groove 17 in the end section of the pump piston 13, an inlet opening 18 in the cylinder sleeve 15 and a channel 19 in the pump housing 10 connectable to the pump interior 11. The pump working space 16 is connected via a pressure valve 20 and a channel 21 to an annular channel 22 in the pump piston 13. From the annular channel 22, a distribution groove 23 branches off in the pump piston 13 and cooperates with outlet channels 24, which are distributed over the circumference of the cylinder liner 15 and of which only one is shown. Each outlet channel 24 is connected to a connection opening 25 for an injection nozzle. From the pump working chamber 16, an axial channel 26 leads to a transverse channel 27 in the pump piston 13. The transverse channel 27 works together with a quantity adjusting element 28, which is axially displaceable on the pump piston section projecting into the pump interior 11. As long as the transverse channel 27 is covered by the quantity adjusting member 28, the pump piston 13 delivers high-pressure fuel from the pump work space 16 via the pressure valve 20, the channel 21, the annular channel 22 and the distributor groove 23 into one of the outlet channels 24. At the moment where the transverse channel 27 emerges from the quantity adjustment member 28, the pump work space 16 is connected to the pump interior 11 and is relieved. The high-pressure delivery to the connection openings 25 is abruptly stopped. The relative position of the quantity adjusting member 28 relative to the pump piston 13 thus determines the amount of fuel that is to be injected via the outlet channels 24.

Zur Betätigung des Mengenverstellorgans 28 greift an diesem ein kugelförmig ausgebildeter Arm eines zweiarmigen Regelhebels 29 an, der auf einem gehäusefesten Zapfen 30 gelagert ist An dem anderen Arm des Regelhebels 29 greift einerseits ein nicht dargestellter Fliehkraftdrehzahlregler und andererseits (in der Zeichnung oben dargestellt) über eine Regelfeder 31 ein Drehzahlverstellhebel 32 an, der über ein nicht dargestelltes Fahrpedal willkürlich in Pfeilrichtung 33 geschwenkt werden kann. Eine Rückstellfeder 34 dient zum Rückstellen des Drehzahlverstellhebels 32 bei Wegfall der Betätigungskraft am Fahrpedal. Der zweiarmig ausgebildete Drehzahlverstellhebel 32 ist dabei um eine am Pumpengehäuse 10 festgelegte Schwenkachse 35 drehbar. Die Kopplung zwischen dem Drehzahlverstellhebel 32 und der Regelfeder 31 erfolgt über eine vorgespannte Schleppfeder 36, die sich einerseits an einem Hebelarm eines Dämpferhebels 37 und andererseits an dem von der Rückstellfeder 34 abgekehrten Arm des Drehzahlverstellhebels 32 abstützt. Dabei drückt die vorgespannte Schleppfeder 36 den Hebelarm des Drehzahlverstellhebels 32 gegen einen Anschlag 38, der auf dem von der Schleppfeder 36 abgekehrten Hebelarm des Dämpferhebels 37 angeordnet ist. Der Dämpferhebel 37 selbst ist auf der Schwenkachse 35 des Drehzahlverstellhebels 32 schwenkbar angeordnet.To actuate the quantity adjustment member 28, a spherical arm of a two-armed control lever 29 engages thereon, which is mounted on a pin 30 fixed to the housing Control spring 31 on a speed adjustment lever 32, which can be pivoted arbitrarily in the direction of arrow 33 via an accelerator pedal, not shown. A return spring 34 serves to reset the speed adjustment lever 32 if the actuating force on the accelerator pedal is lost. The two-armed speed adjustment lever 32 can be rotated about a pivot axis 35 fixed on the pump housing 10. The coupling between the speed adjustment lever 32 and the control spring 31 takes place via a preloaded drag spring 36 which is supported on the one hand on a lever arm of a damper lever 37 and on the other hand on the arm of the speed adjustment lever 32 remote from the return spring 34. The pretensioned drag spring 36 presses the lever arm of the speed adjustment lever 32 against a stop 38 which is arranged on the lever arm of the damper lever 37 remote from the drag spring 36. The damper lever 37 itself is pivotally arranged on the pivot axis 35 of the speed adjustment lever 32.

Der Dämpferhebel 37 ist Teil einer Dämpfungsvorrichtung 40, die der Verbesserung der Laufruhe der Brennkraftmaschine beim schnellen Betätigen des Drehzahlverstellhebels 32 dient und das sog. Fahrzeugruckeln beim schnellen Niederdrücken bzw. Loslassen des Fahrpedals beseitigt. Die hydraulische Dämpfungsvorrichtung 40 ist im Pumpeninnenraum 11 angeordnet und umfaßt ein Dämpfergehäuse 41 mit einer Längsbohrung 42, die an beiden Stirnenden verschlossen ist, eine in der Längsbohrung 42 verschiebbare Führungshülse 43 und einen in der Führungshülse 43 gleitenden Dämpfungskolben 44. Dämpfergehäuse 41 und Führungshülse 43 bilden in bekannter Weise einen Dämpfungszylinder, der zusammen mit der einen Stirnseite des Dämpfungskolbens 44 eine Dämpfungskammer 45 begrenzt. Die Dämpfungskammer 45 steht einerseits über ein erstes Rückschlagventil 46 und eine erste Drossel 47, die beide im Dämpfungskolben 44 angeordnet sind, und andererseits über eine zweite Drossel 48 und ein zweites Rückschlagventil 49, die beiden im Dämpfergehäuse 41 angeordnet sind, mit dem Pumpeninnenraum 11 in Verbindung. Die Verbindung zwischen dem Ausgang der ersten Drossel 47 und dem Pumpeninnenraum 11 wird dabei von einer ersten Radialbohrung 60 in der Führungshülse 43 und einer ersten radialen Durchgangsöffnung 61 in dem Dämpfergehäuse 41 gewährleistet. Der Durchmesser der Durchgangsöffnung 61 ist gegenüber dem der Radialbohrung 60 sehr groß bemessen, so daß auch bei einer Verschiebebewegung der Führungshülse 43 relativ zum Dämpfergehäuse 41 die Durchgangsöffnung 61 stets die Radialbohrung 60 zum Pumpeninnenraum 11 hin freigibt. Die beiden Rückschlagventile 46,49 sind so angeordnet, daß die Sperrichtung des ersten Rückschlagventils 46 zum Pumpeninnenraum 11 hin und die des zweiten Rückschlagventils 49 zur Dämpfungskammer 45 hin gerichetet ist. An dem Dämpfungskolben 44 ist der den Anschlag 38 tragende Hebelarm des Dämpferhebels 37 gelenkig befestigt, während der die vorgespannte Schleppfeder 36 tragende Hebeiarm des Dämpferhebels 37 an der Regelfeder 31 angekoppelt ist.The damper lever 37 is part of a damping device 40 which serves to improve the smooth running of the internal combustion engine when the speed adjustment lever 32 is actuated quickly and eliminates the so-called vehicle jerking when the accelerator pedal is depressed or released quickly. The hydraulic damping device 40 is arranged in the pump interior 11 and comprises a damper housing 41 with a longitudinal bore 42 which is closed at both ends, a guide sleeve 43 which can be displaced in the longitudinal bore 42 and a damping piston 44 which slides in the guide sleeve 43. Damper housing 41 and guide sleeve 43 form in a known manner, a damping cylinder which, together with the one end face of the damping piston 44, delimits a damping chamber 45. The damping chamber 45 is on the one hand via a first check valve 46 and a first throttle 47, both of which are arranged in the damping piston 44, and on the other hand via a second throttle 48 and a second check valve 49, both of which are arranged in the damper housing 41, with the pump interior 11 in Connection. The connection between the outlet of the first throttle 47 and the pump interior 11 is ensured by a first radial bore 60 in the guide sleeve 43 and a first radial through opening 61 in the damper housing 41. The diameter of the through opening 61 is that of the Radial bore 60 dimensioned very large, so that even with a sliding movement of the guide sleeve 43 relative to the damper housing 41, the through hole 61 always releases the radial bore 60 to the pump interior 11. The two check valves 46, 49 are arranged such that the blocking direction of the first check valve 46 towards the pump interior 11 and that of the second check valve 49 towards the damping chamber 45 are directed. The lever arm of the damper lever 37 carrying the stop 38 is articulated to the damping piston 44, while the lifting arm of the damper lever 37 carrying the pretensioned drag spring 36 is coupled to the control spring 31.

Die Führungshülse 43 begrenzt zusammen mit dem Dämpfungskolben 44 an ihrer einen Stirnseite einen Steuerraum 50, der über einen radialen Einlaßkanal 51 mit dem Pumpeninnenraum 11 verbunden ist. Das andere Stirnende der Führungshülse 43 ist mit einer Abschlußplatte 52 abgedeckt, die gleichzeitig als Führung für eine Druckfeder 53 dient. Führungshülse 43 und Abschlußplatte 52 begrenzen einen die Druckfeder 53 aufnehmenden Entlastungsraum 54, der über einen Auslaßkanal 55 mit einer Kraftstoffrücklaufleitung verbunden ist, die durch den Pfeil 56 angedeutet ist Die Druckfeder 53 stützt sich an einer Anschlagplatte 57 ab, deren räumliche Lage innerhalb des Entlastungsraums 54 mittels eines im Dämpfergehäuse 41 verschraubbaren Justierstiftes 58 verstellbar ist Durch mehr oder weniger starkes Eindrehen des Justierstiftes 58 läßt sich die Vorspannung der Druckfeder 53 einstellen.The guide sleeve 43, together with the damping piston 44, delimits on one end face a control chamber 50 which is connected to the pump interior 11 via a radial inlet duct 51. The other end of the guide sleeve 43 is covered with an end plate 52, which also serves as a guide for a compression spring 53. Guide sleeve 43 and end plate 52 delimit a relief chamber 54 which receives the compression spring 53 and is connected via an outlet channel 55 to a fuel return line, which is indicated by the arrow 56. The compression spring 53 is supported on a stop plate 57, the spatial position of which in the relief chamber 54 is adjustable by means of an adjusting pin 58 which can be screwed into the damper housing 41. The prestressing of the compression spring 53 can be adjusted by turning the adjusting pin 58 more or less.

Um die Dämpfungsvorrichtung 40 nicht in dem Bereich der Leerwege des Drehzahlverstellhebels 32, also dann wenn noch keine Einspritzung erfolgt, wirksam werden zu lassen, sind zu den Drosseln 47, 48 zwei ungedrosselte Strömungswege parallel geschaltet, die in bestimmten Bereichen der Verstellbewegung des Dämpfungskolbens 44 die Dämpfungskammer 45 unter Umgehung der beiden Drosseln 47, 48 mit dem Pumpeninnenraum 11 verbinden und damit die Drosselwirkung aufheben. Da bei unterschiedlichen Drehzahlen der Brennkraftmaschine und damit der Kraftstoffeinspritzpumpe diese Leerwege des Drehzahlverstellhebels 32 in anderen Verschiebebereichen des Dämpfungskolbens 44 liegen, verlagern auch entsprechend sich diese Strömungswege im Verstellbereich des Dämpfungskolbens 44 durch Verschieben der Führungshülse 43, die sich mit steigender Drehzahl der Brennkraftmaschine und dem damit ansteigenden Druck im Pumpeninnenraum 11 in der Zeichnung nach rechts gegen die Wirkung der Druckfeder 53 verschiebt. Der erste Strömungsweg 67 wird dabei von einer die erste Drossel 47 im Dämpfungskolben 44 umgehenden Bypaßbohrung 62, der eine Steueroffnung bildenden ersten Radialbohrung 60 in der Führungshülse 43 und der mit dieser korrespondiemden ersten Durchgangsöffnung 61 im Dämpfergehäuse 41 gebildet. Der Durchmesser der ersten Radialbohrung 60 ist dabei so groß gewählt, daß je nach Stellung des Dämpfungskolbens 44 relativ zur Führungshülse 43 nur die Mündung der ersten Drossel 47 oder zusätzlich auch die Mündung der Bypaßbohrung 62 von der Führungshülse 43 zum Pumpeninnenraum 11 hin freigegeben sind. Der zweite ungedrosselte Strömungsweg 68 zwischen der Dämpfungskammer 45 und dem Pumpeninnenraum 11 wird von einer Ringnut 63 in der Dämpfungskammer 45, von einer mit der Ringnut 63 in ständiger Verbindung stehenden Axialnut 64 am Umfang des Dämpfungskolbens 44, einer zweiten Radialbohrung 65 in der Führungshülse 43 und einer zweiten Durchgangsöffnung 66 im Dämpfergehäuse 41 gebildet. Der Durchmesser der Durchgangsöffnung 66 ist dabei so groß gewählt, daß über den gesamten Verschiebebereich der Führungshülse 43 die zweite Radialbohrung 65 in der Führungshülse 43 zum Pumpeninnenraum 11 hin freigegeben ist. Die Ringnut 63 in der Dämpfungskammer 45 ist so ausgebildet, daß sie nach einem bestimmten Verschiebeweg des Dämpfungskolbens 44, der von der relativen Lage von Dämpfungskolben 44 und Führungshülse 43 abhängt, gegenüber der restlichen Dämpfungskammer 45 abgeschlossen ist. Die Axialnut 64 im Dämpfungskolben 44 hat eine solche Länge, daß über den gesamten Verschiebeweg des Dämpfungskolbens 44 die Ringnut 63 mit der zweiten Radialbohrung 65 in der Führungshülse 43 verbunden bleibt. Je nach Verschiebestellung der Führungshülse 43 benötigt der Dämpfungskolben 44 einen mehr oder weniger großen Verschiebeweg, um die Ringnut 63 gegenüber der Dämpfungskammer 45 abzuschließen - und damit den Strömungsweg 68 zu sperren - bzw. wieder freizugeben - und damit den Strömungsweg 68 zu öffnen -. Dieser Strömungsweg 68 ist damit in beiden Richtungen der Verschiebewegung des Dämpfungskolbens 44 wirksam, während der erste ungedrosselte Strömungsweg 67 infolge des im Strömungsweg 67 liegenden ersten Rückschlagventils 46 nur bei einer Verschiebung des Dämpfungskolbens 44 in der Zeichnung nach links, also bei Verstellung des Drehzahlverstellhebels 32 in Richtung kleinerer Kraftstoffördermengen, wirksam werden kann.In order not to allow the damping device 40 to become effective in the area of the idle travel of the speed adjustment lever 32, i.e. when no injection has yet taken place, two unthrottled flow paths are connected in parallel to the throttles 47, 48, which flow in certain areas of the adjustment movement of the damping piston 44 Connect the damping chamber 45 bypassing the two throttles 47, 48 to the pump interior 11 and thus cancel the throttling effect. Since, at different speeds of the internal combustion engine and thus the fuel injection pump, these idle paths of the speed adjustment lever 32 lie in other displacement ranges of the damping piston 44, these flow paths also shift accordingly in the adjustment range of the damping piston 44 by shifting the guide sleeve 43, which changes with increasing speed of the internal combustion engine and thus with it increasing pressure in the pump interior 11 in the drawing to the right against the action of the compression spring 53. The first flow path 67 is formed by a bypass bore 62 bypassing the first throttle 47 in the damping piston 44, the first radial bore 60 forming a control opening in the guide sleeve 43 and the first through opening 61 in the damper housing 41 corresponding thereto. The diameter of the first radial bore 60 is chosen so large that, depending on the position of the damping piston 44 relative to the guide sleeve 43, only the mouth of the first throttle 47 or additionally the mouth of the bypass bore 62 from the guide sleeve 43 to the pump interior 11 are released. The second unthrottled flow path 68 between the damping chamber 45 and the pump interior 11 is provided by an annular groove 63 in the damping chamber 45, by an axial groove 64 in constant communication with the annular groove 63 on the circumference of the damping piston 44, a second radial bore 65 in the guide sleeve 43 and a second through opening 66 is formed in the damper housing 41. The diameter of the passage opening 66 is chosen so large that the second radial bore 65 in the guide sleeve 43 to the pump interior 11 is released over the entire displacement range of the guide sleeve 43. The annular groove 63 in the damping chamber 45 is designed such that it is closed off from the rest of the damping chamber 45 after a certain displacement path of the damping piston 44, which depends on the relative position of the damping piston 44 and guide sleeve 43. The axial groove 64 in the damping piston 44 has a length such that the annular groove 63 remains connected to the second radial bore 65 in the guide sleeve 43 over the entire displacement path of the damping piston 44. Depending on the displacement position of the guide sleeve 43, the damping piston 44 requires a more or less large displacement path in order to close the annular groove 63 with respect to the damping chamber 45 - and thus to block the flow path 68 - or to release it again - and thus to open the flow path 68. This flow path 68 is thus effective in both directions of the displacement movement of the damping piston 44, while the first unthrottled flow path 67, as a result of the first check valve 46 located in the flow path 67, only moves the damping piston 44 to the left in the drawing, i.e. when the speed adjustment lever 32 is adjusted in Direction of smaller fuel flow rates, can take effect.

Fahrzeugruckeln macht sich hauptsächlich beiniedrigen Drehzahlen bemerkbar und wird hier durch die vorstehend beschriebene Dämpfungsvorrichtung 40 weitgehend unterdrückt. Im höheren Drehzahlbereich ist infolge der hohen kinetischen Energie der Schwungmassen ein Fahrzeugruckeln nicht mehr bemerkbar, so daß eher die Dämpfungsvorrichtung 40 überflüssig ist und für das Fahrverhalten eher Nachteile bringt. Aus diesem Grund wird bei höheren Drehzahlen die Dämpfungsvorrichtungen 40 abgeschaltet, so daß ihre Dämpfungswirkung gleich Null ist. Hierzu ist ein dritter ungedrosselter Strömungsweg 69 vorgesehen, der bei höheren Drehzahlen die Dämpfungskammer 45 unmittelbar mit dem Pumpeninnenraum 11 verbindet und damit die Dämpfungsvorrichtung 40 kurzschließt. Unterhalb einer bestimmten Drehzahl ist der dritte ungedrosselte Strömungsweg 69 verriegelt. Die Verriegelung und Freigabe des Strömungsweges 69 erfolgt mittels eines Druckventils 70, das hier als Schieberventil ausgebildet ist. In dem Dämpfergehäuse 41 ist hierzu eine Sackbohrung 71 eingebracht, die nahe dem Sackgrund über eine Enflastungsbohrung 72 mit dem Entlastungsraum 54 verbunden ist. In der Sackbohrung 71 gleitet ein Steuerkolben 73, der auf seiner der Mündung der Sackbohrung 71 zugekehrten Stirnseite vom Druck im Pumpeninnenraum 11 beaufschlagt ist und sich mit seiner anderen Stirnseite über eine Druckfeder 74 am Sackgrund abstützt. Der dritte Strömungsweg 69 wird von zwei Bohrungen 75, 76 im Dämpfergehäuse 41 gebildet, die einerseits mit dem Pumpeninnenraum 11 und andererseits mit der Dämpfungskammer 45 in Verbindung stehen und in einer Querschnittsebene diametral in der Sackbohrung 71 münden. Mit den beiden Mündungen der Bohrungen 75, 76 arbeitet eine Steuemut 77 am Steuerkolben 73 zusammen, die je nach Verschiebestellung des Steuerkolbens 73 den Durchgang von der Bohrung 76 zur Bohrung 75 freigibt oder absperrt. Durch geeignete Wahl der Druckfeder 74 ist das Druckventil 70 so eingestellt, daß bei Überschreiten eines bestimmten Drucks im Pumpeninnenraum 11 der Steuerkolben 73 gegen die Kraft der Druckfeder 74 soweit verschoben ist, daß die Bohrungen 75, 76 miteinander verbunden sind und damit die Dämpfungskammer 45 an dem Pumpeninnenraum 11 angeschlossen ist. Ein solcher Druckanstieg im Pumpeninnenraum 11 erfolgt erst bei höheren Drehzahlen der Brennkraftmaschine und damit der Förderpumpe 12.Vehicle jerking is mainly noticeable at low engine speeds and is largely suppressed here by the damping device 40 described above. In the higher speed range, due to the high kinetic energy of the flywheels, vehicle jerking is no longer noticeable, so that the damping device 40 is rather superfluous and tends to have disadvantages for driving behavior. For this reason, the damping devices 40 are switched off at higher speeds, so that their damping effect is zero. For this is a third unthrottled flow way 69 provided that connects the damping chamber 45 directly to the pump interior 11 at higher speeds and thus shorts the damping device 40. The third unthrottled flow path 69 is locked below a certain speed. The flow path 69 is locked and released by means of a pressure valve 70, which is designed here as a slide valve. For this purpose, a blind hole 71 is made in the damper housing 41, which is connected to the relief space 54 near the bottom of the bag via a relief bore 72. A control piston 73 slides in the blind bore 71, which is acted upon by the pressure in the pump interior 11 on its end face facing the mouth of the blind bore 71 and is supported with its other end face by a compression spring 74 on the bag base. The third flow path 69 is formed by two bores 75, 76 in the damper housing 41, which are connected on the one hand to the pump interior 11 and on the other hand to the damping chamber 45 and open diametrically in the blind bore 71 in a cross-sectional plane. With the two mouths of the bores 75, 76, a control groove 77 cooperates on the control piston 73, which, depending on the displacement position of the control piston 73, releases or blocks the passage from the bore 76 to the bore 75. By a suitable choice of the compression spring 74, the pressure valve 70 is set such that when a certain pressure in the pump interior 11 is exceeded, the control piston 73 is displaced so far against the force of the compression spring 74 that the bores 75, 76 are connected to one another and thus the damping chamber 45 the pump interior 11 is connected. Such an increase in pressure in the pump interior 11 takes place only at higher speeds of the internal combustion engine and thus of the feed pump 12.

Die Wirkungsweise der vorstehend beschriebenen Dämpfungsvorrichtung 40 ist wie folgt :

  • Wird das Fahrpedal niedergedrückt ("Gasgeben") und dadurch der Drehzahlverstellhebel 32 in Richtung Pfeil 33 unter Spannen der Rückstellfeder 34 verschwenkt, so wird die Vorgabekraft über die Schleppfeder 36 dem Dämpfungskolben 44 zugeführt, der sich in der Zeichnung nach rechts bewegt. Sobald der Dämpfungskolben 44 die Ringnut 63 gegenüber der Dämpfungskammer 45 abgeschlossen hat, läßt die zweite Drossel 48 eine weitere Bewegung des Dämpfungskolbens 44 nur verzögert zu. Damit überträgt der Dämpfungskolben 44 die Vorgabekraft auch nur verzögert über die Regelfeder 31 auf den Regelhebel 29, der seinerseits nur verzögert das Mengenverstellorgan 28 verschiebt. Damit wird beim schnellen Verschwenken des Drehzahlverstellhebels 32 infolge rascher Fahrpedalbetätigung die Einspritzmengenänderung nur verzögert durchgeführt, so daß das Fahrzeug ruckelfrei beschleunigt wird. In umgekehrter Richtung, also beim schnellen Loslassen des Fahrpedals wirkt die Rückstellfeder 34 über den Drehzahlverstellhebel 32 und den Anschlag 38 auf den Dämpfungskolben 44, so daß dieser in derZeichnung nach links verschoben wird. Die Verschiebebewegung des Dämpfungskolbens 44 wird nunmehr über die erste Drossel 47 verzögert. Die verzögerte Verschiebewegung des Dämpfungskolbens löst nur eine verzögerte Verstellung des Regelhebels 29 und damit das Mengenverstellorgans 28 aus. Damit erfolgt auch die Verzögerung des Fahrzeugs weitgehend ruckeifrei. Nach Zurücklegen eines bestimmten Verschiebewegs des Dämpfungskolbens 44 wird die Ringnut 63 zur Dämpfungskammer 45 hin freigegeben und damit die Dämpfungswirkung aufgehoben. Die weitere Übertragung der Rückstellbewegung des Drehzahlverstellhebels 32 auf den Regelhebel 29 erfolgt dann ungedämpft.
The function of the damping device 40 described above is as follows:
  • If the accelerator pedal is depressed ("accelerating") and thereby the speed adjustment lever 32 is pivoted in the direction of arrow 33 while tensioning the return spring 34, the specified force is supplied via the drag spring 36 to the damping piston 44, which moves to the right in the drawing. As soon as the damping piston 44 has closed the annular groove 63 with respect to the damping chamber 45, the second throttle 48 only permits a further movement of the damping piston 44 with a delay. The damping piston 44 thus transmits the specified force only with a delay via the control spring 31 to the control lever 29, which in turn only moves the quantity adjusting element 28 with a delay. Thus, when the speed adjustment lever 32 is swiveled rapidly as a result of rapid accelerator pedal actuation, the injection quantity change is carried out only with a delay, so that the vehicle is accelerated smoothly. In the opposite direction, that is to say when the accelerator pedal is released quickly, the return spring 34 acts on the damping piston 44 via the speed adjustment lever 32 and the stop 38, so that the latter is shifted to the left in the drawing. The displacement movement of the damping piston 44 is now delayed via the first throttle 47. The delayed displacement movement of the damping piston only triggers a delayed adjustment of the control lever 29 and thus the quantity adjusting member 28. This means that the deceleration of the vehicle is largely smooth. After covering a certain displacement path of the damping piston 44, the annular groove 63 is released towards the damping chamber 45 and thus the damping effect is canceled. The further transmission of the return movement of the speed adjustment lever 32 to the control lever 29 then takes place without damping.

Claims (10)

1. Fuel injection pump for intemal-combustion engines, particularly diesel internal-combustion engines, with a pump plunger (13) which withdraws fuel from a fuel-filled pump interior space (11), said space (11) being under delivery pressure, and delivers it under high pressure to injection nozzles, with a quantity adjustment member (28), the position of which relative to the pump plunger determines the fuel injection quantity delivered per pump-plunger stroke, with a two-armed governing lever (29) which engages with one lever arm on the quantity adjustment member (28) for the purpose of actuating it and the other lever arm of which is coupled via at least one governing spring (31) to an arbitrarily actuable speed-adjusting lever (32) which can be swivelled for the purpose of speed adjustment about a swivelling spindle (35) fixed to the pump casing, counter to a return spring (34), and with a hydraulic damping device (40) comprising a damping cylinder and a damping plunger, with restrictor, axially displaceable therein and which, for the purpose of improving the smoothness of running of the internal-combustion engine upon rapid actuation of the speed-adjusting lever (32), permits only a delayed adjustment of the quantity adjustment member (28), characterised in that the coupling between the speed-adjusting lever (32) and the governing spring (31) is effected via a prestressed drag spring (36) which is braced, on the one hand, against the speed-adjusting lever (32) and, on the other hand, against a lever arm, connected to the governing spring (31), of a damper lever (37) swivellable about the swivelling spindle (35) of the speed-adjusting lever (32) and places the speed-adjusting lever (32) against a stop (38) on the damper lever (37) connected in articulated fashion to the damping plunger (44), in that the restrictor (47) arranged in the damping plunger (44) connects a damping chamber (45) enclosed by damping plunger (44) and damping cylinder (41, 42, 43) to the pump interior space (11) via a nonretum valve (46) having its opening direction towards the damping chamber (45) and in that a further restrictor (48) connects the damping chamber (45) to the pump interior space (11) via a further non- return valve (49) having its blocking direction towards the damping chamber (45).
2. Fuel injection pump according to Claim 1, characterised in that unrestricted flow paths (67, 68) between the damping chamber (45) and the pump interior space (11) are connected in parallel with the restrictors (47,48) in such a way that they are opened only in ranges of the displacement movement of the damping plunger (44) in which idle motions of the speed-adjusting lever (32) occur.
3. Fuel injection pump according to Claim 2, characterised in that the damping cylinder comprises a damper casing (41) fixed in the pump interior space (11) and a guide sleeve (43) which is axially displaceable in a damper-casing bore (42) dosed on both sides and in which the damping plunger (44) is guided, in that at least one flow path (67) has a control opening (60), which is arranged in the guide sleeve (43), is opened towards the pump interior space (11) and, for the blockage and opening of the flow path (67), interacts with a channel (62) leading in the damping cylinder (44) to the damping chamber (45), in that, together with the damping plunger (44), one end of the guide sleeve (43) delimits a control space (50) connected to the pump interior space (11) and the other end of the guide sleeve (43), said end being covered by a closure plate (52), delimits a relief space (54) connected to a fuel return (56) and in that a compression spring (53), preferably with adjustable prestress, braced against the closure plate (52) is arranged in the relief space (54).
4. Fuel injection pump according to Claim 3, characterised in that the channel (67) is formed by a bypass bore (62) which bridges the restrictor (47) in the damping plunger (44) and opens on the circumference of the damping plunger (44) at a distance from the mouth of the restrictor (47), and in that the diameter selected for the control opening (60) is such that it is capable of covering the mouths of restrictor (47) and/or bypass bore (62).
5. Fuel injection pump according to Claim 3 or 4, characterised in that a further flow path (68) is formed by an annular groove (63) in the damping chamber (45), said annular groove being shut off from or opened again to the damping chamber (45) aftera displacement path of the damping plunger (44) which is dependent on the relative position of guide sleeve (43) and damping plunger (44), by a radial bore (65) in the guide sleeve (43), said radial bore opening towards the pump interior space (11), and by an axial groove (64) in the damping plunger (44), said axial groove connecting the annular groove (63) to the radial bore (65) over the entire displacement path of the damping plunger (44).
6. Fuel injection pump according to one of Claims 1-5, characterised in that the further restrictor (48) and the further nonretum valve (49) are arranged in the damper casing (41).
7. Fuel injection pump according to one of Claims 1-6, characterised in that a third unrestricted flow path (69) is provided directly between damping chamber (45) and pump interior space (11), said flow path being controlled in such a way by a pressure regulating valve (70) controlled by the pressure in the pump interior space (11) that it is open above a pressure value in the pump interior space (11) which corresponds to relatively high speeds of the intemal-combustion engine.
8. Fuel injection pump according to Claim 7, characterised in that the pressure regulating valve (70) is designed as a plunger valve which is arranged in the damper casing (41) and the valve connections of which are connected, on the one hand, to the damping chamber (45) and, on the other hand, to the pump interior space (11) and the hydraulic control input of which is connected to the pump interior space (11).
9. Fuel injection pump according to Claim 8, characterised in that a blind bore (71), which is open towards the pump interior space (11) and in which a control plunger (73) is guided in such a way as to be axially displaceable counter to the action of a compression spring (74) braced against said control plunger and against the base of the blind bore, is made in the damper casing (41) and in that the control plunger (73) bears a control groove (77) which interacts for the opening or closure of the third flow path (69) with two radial control bores (75, 76) opening diametrically in the blind bore (71), one of which is connected to the pump interior space (11) and the other of which is connected to the damping chamber (45).
10. Fuel injection pump according to Claim 9, characterised in that that end portion of the blind bore (71) which accommodates the compression spring (74) is connected via a relief bore (72) to the relief space (54) in the damper housing (41).
EP19880118279 1987-12-09 1988-11-03 Fuel injection pump for internal-combustion engines, particularly for diesel engines Expired - Lifetime EP0319707B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3741638A DE3741638C1 (en) 1987-12-09 1987-12-09 Fuel injection pump for internal combustion engines, in particular diesel internal combustion engines
DE3741638 1987-12-09

Publications (3)

Publication Number Publication Date
EP0319707A2 EP0319707A2 (en) 1989-06-14
EP0319707A3 EP0319707A3 (en) 1990-06-13
EP0319707B1 true EP0319707B1 (en) 1991-09-25

Family

ID=6342160

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19880118279 Expired - Lifetime EP0319707B1 (en) 1987-12-09 1988-11-03 Fuel injection pump for internal-combustion engines, particularly for diesel engines

Country Status (4)

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US (1) US4884542A (en)
EP (1) EP0319707B1 (en)
JP (1) JPH01193037A (en)
DE (2) DE3741638C1 (en)

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US5148789A (en) * 1989-11-07 1992-09-22 Kubota Corporation Governor device of diesel engine
DE3937922A1 (en) * 1989-11-15 1991-05-16 Bosch Gmbh Robert FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES
FR2720786B1 (en) * 1994-06-07 1996-07-26 Renault Device for controlling the flow rate of an injection pump and mechanism for regulating the cruising speed of a vehicle equipped with such a pump.
DE19860672A1 (en) * 1998-12-29 2000-07-13 Bosch Gmbh Robert Piston pump for high-pressure fuel generation
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US7543558B2 (en) 2004-11-10 2009-06-09 Buck Diesel Engines, Inc. Multicylinder internal combustion engine with individual cylinder assemblies
US7287494B2 (en) 2004-11-10 2007-10-30 Buck Supply Co., Inc. Multicylinder internal combustion engine with individual cylinder assemblies and modular cylinder carrier
US7287493B2 (en) 2004-11-10 2007-10-30 Buck Supply Co., Inc. Internal combustion engine with hybrid cooling system
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Also Published As

Publication number Publication date
US4884542A (en) 1989-12-05
DE3741638C1 (en) 1988-12-01
EP0319707A3 (en) 1990-06-13
EP0319707A2 (en) 1989-06-14
DE3865185D1 (en) 1991-10-31
JPH01193037A (en) 1989-08-03

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