EP0346607A2 - Hydraulic control device for fuel injection systems of internal combustion engines - Google Patents

Hydraulic control device for fuel injection systems of internal combustion engines Download PDF

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Publication number
EP0346607A2
EP0346607A2 EP19890108081 EP89108081A EP0346607A2 EP 0346607 A2 EP0346607 A2 EP 0346607A2 EP 19890108081 EP19890108081 EP 19890108081 EP 89108081 A EP89108081 A EP 89108081A EP 0346607 A2 EP0346607 A2 EP 0346607A2
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EP
European Patent Office
Prior art keywords
control
piston
fuel injection
working
pump
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.)
Withdrawn
Application number
EP19890108081
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German (de)
French (fr)
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EP0346607A3 (en
Inventor
Rudolf Babitzka
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Robert Bosch GmbH
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Robert Bosch GmbH
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Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP0346607A2 publication Critical patent/EP0346607A2/en
Publication of EP0346607A3 publication Critical patent/EP0346607A3/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M41/00—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor
    • F02M41/08—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined
    • F02M41/10—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor
    • F02M41/12—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor the pistons rotating to act as the distributor
    • F02M41/123—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor the pistons rotating to act as the distributor characterised by means for varying fuel delivery or injection timing
    • F02M41/125—Variably-timed valves controlling fuel passages
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M41/00—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor
    • F02M41/08—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined
    • F02M41/10—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor
    • F02M41/12—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor the pistons rotating to act as the distributor
    • F02M41/123—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor the pistons rotating to act as the distributor characterised by means for varying fuel delivery or injection timing
    • F02M41/125—Variably-timed valves controlling fuel passages
    • F02M41/126—Variably-timed valves controlling fuel passages valves being mechanically or electrically adjustable sleeves slidably mounted on rotary piston
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/20—Varying fuel delivery in quantity or timing
    • F02M59/22—Varying quantity or timing by adjusting cylinder-head space
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/20—Varying fuel delivery in quantity or timing
    • F02M59/36—Varying fuel delivery in quantity or timing by variably-timed valves controlling fuel passages to pumping elements or overflow passages
    • F02M59/366—Valves being actuated electrically
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
    • F02M59/46—Valves
    • F02M59/466—Electrically operated valves, e.g. using electromagnetic or piezoelectric operating means

Definitions

  • the invention relates to a hydraulic control device according to the preamble of the main claim.
  • hydraulic control devices which work with closed liquid-filled rooms and in which pistons and valve surfaces are acted upon
  • the basic relationship between the surface exposed to the liquid and that of the liquid pressures and the surfaces results problems that can be derived when the time factor plays a role.
  • the same force can be achieved, for example, by a low pressure in a large area or a high pressure in a small area, the mastery of the volume, ie the amount flowing off per unit of time, being decisive for the time factor.
  • the valves used for control should on the one hand have an extremely short opening and closing time factor and on the other hand the lowest possible flow resistance, ie the largest possible control cross section.
  • Such a hydraulic control device becomes problematic when large volumes of liquid under high pressure are to be controlled in very short time periods, as is the case, for example, with fuel injection, in which the speed changes in less than a millisecond and this changes Control must run.
  • the fuel injection can be interrupted by relieving the pressure in the pump work space via a relief channel, this channel being controlled via a solenoid valve.
  • the movable valve member of the solenoid valve is un because of the high pressure of the pump work space acted upon indirectly, so that when the valve is closed, considerable locking forces must be applied in accordance with the functional surface acting in the opening direction on the movable valve member, as long as no outflow is to take place.
  • a solenoid valve that is open when de-energized as is usually used for such a purpose for safety reasons, the energy consumption of the magnet is proportional to the required locking forces.
  • a relatively large cross-section must usually be selected with the short times available, which leads to large, expensive magnets and correspondingly high power consumption.
  • a pressure line branches off from the pump work space, via which the fuel is fed to an alternative piston, which is always displaced by the delivery pressure of the injection pump when the solenoid valve is open, the one on the rear of the alternative piston existing space is relieved of pressure by the solenoid valve.
  • This piston is loaded by a return spring that this in the case of evasive fuel injected towards the end of the injection and after the end of the high-pressure delivery via the injection nozzle into the combustion chamber of the internal combustion engine. As a result, the spray duration is extended and the internal combustion engine runs quieter.
  • the hydraulic control according to the invention with the characterizing features of the main claim has the advantage that the liquid volume that has to flow through the valve for a certain displacement of the control piston within a certain time that this volume the upstream in the control piston, swallowed during the movement, is reduced by the size ratio of the working surface to the control surface. This means that if the control surface is twice as large as the working surface, the volume that has to flow through the valve is just half as large as the volume flowing through the control surface.
  • the pressure in the work area increases inversely proportional to the control room pressure, ie the pressure in the work area is greater by the ratio of the control area to the work area than in the control room.
  • This pressure in the working area in turn acts on the movable valve member of the valve, so that its closing forces must be adapted to this pressure. Due to the area ratio between the working area and the control area, the volume to be controlled by the valve can be greatly reduced, the opening cross section of the valve can also be reduced accordingly, it now advantageously being found that, with the closing force remaining the same, a time-cross-sectional gain corresponding to the area ratio can be achieved by using the stepped piston is.
  • the advantage can also be described in such a way that, due to the reduction in the volume to be controlled, despite the increase in pressure which is given, while the closing force of the movable valve member remains the same, the area ratio corresponds the time opening cross-sectional gain is available, that is, with the same amount of closing force on the valve, a faster stroke of the control piston can be achieved or, conversely, for a certain speed of the control piston, a smaller opening cross section on the valve is sufficient in the invention.
  • This advantage has a particular effect on fuel injection pumps for internal combustion engines, in which the working cycles are extremely short - for example in a four-cylinder internal combustion engine and 4000 rpm, which corresponds to approximately 66 working cycles of the alternative piston per second and this varies depending on the speed .
  • a solenoid valve is used as the control valve, so that the advantage of the invention of the lower actuating forces required has a particular effect, since the effort for generating a magnetic force not only increases disproportionately to the actuating force size, but also in terms of costs.
  • the stepped piston is spring-loaded in the direction of the pump work space, so that it is automatically pushed back into an initial position after the pressure in the pump work space has been reduced.
  • the stepped piston can serve as an escape piston or for controlling a relief channel.
  • the control piston working as an evasive piston is displaced by the pressure in the pump work space against the restoring force as soon as the valve is open, a volume being stored in front of its control surface, which volume is then returned by the control piston towards the end of the injection.
  • this return leads directly to the injection via the injection valve or that this storage quantity is supplemented by the controller of the injection pump for injection.
  • an extension of the spraying time is achieved by this device, which is particularly important when idling, in order to achieve quiet operation of the machine.
  • the control piston controls the passage of the relief channel
  • a large outflow cross section on the control piston is controlled according to the invention by the small control valve.
  • FIG. 1 shows a distributor injection pump in longitudinal section with the step piston as a pilot-operated valve
  • FIG. 2 shows a detail of the distributor pump according to FIG. 1 with the step piston as an evasive piston, on an enlarged scale.
  • a pump piston 1 which also serves as a distributor, is set into a reciprocating and simultaneously rotating movement by a drive shaft 2 and with the aid of a cam gear 3.
  • fuel is conveyed from a pump working chamber 4 via a longitudinal distribution groove 5 to one of a plurality of pressure channels 6, which are arranged around the pump piston 1 at uniform angular intervals and each lead to a combustion chamber (not shown) of an internal combustion engine.
  • the pump work chamber 4 is supplied with fuel via a suction channel 7 from a suction chamber 8 which is present in the housing of the injection pump and is filled with fuel, in that the suction channel 7 is opened by longitudinal control grooves 9 provided in the pump piston 1 during the suction stroke of the pump piston 1.
  • the number of control grooves 9 corresponds to the number of pressure channels 6 and thus to the number of pressure strokes carried out per revolution of the pump piston.
  • the quantity to be injected per stroke into one of the pressure channels 6 is determined by the axial position of a slide valve 11 arranged around the pump piston 1. This axial position is determined by a speed controller 12 and an arbitrarily actuated adjusting lever 13, evaluating the respective speed and load (the load can correspond, for example, to the position of the accelerator pedal of the motor vehicle).
  • the suction chamber 8 is supplied with fuel by a feed pump 14, which is driven by the drive shaft 2 and supplies fuel from a fuel tank 15 and a suction line 16.
  • the output pressure of the feed pump 14 and thus the pressure in the suction chamber 8 are controlled by a pressure control valve 17, this pressure also increasing the speed also increases according to a desired function.
  • the cam drive 3 and the speed controller 12 are arranged in the suction chamber 8 and are thus acted upon on all sides by this pressure and are lubricated by this fuel.
  • the cam drive 3 has a roller ring 19 carrying rollers 18, which is rotatably mounted in the housing by a certain angle and in the U-shaped cross section of which the rollers 18 are mounted.
  • This roller ring 19 is coupled in a rotationally locking manner to an injection adjustment piston 22 via an adjustment bolt 21, this injection adjustment piston 22 being shown rotated by 90 ° in the drawing, ie working perpendicular to the plane of the illustration.
  • In the inner bore of this roller ring 19 there is a claw coupling in which claws 23 on the drive side 2 of the drive shaft 2 mesh with claws 24 on the output side of the pumping and distributing piston 1, so that the pumping and distributing piston 1 independently of the drive shaft 2 exert a lifting movement while rotating can.
  • An end cam disk 25 is arranged on the pump piston 1 and runs with its end cam 26 on the rollers 18, the number of end cams in turn corresponding to the number of pressure channels 6.
  • the front cam disk 25 is supported by springs 27, only one of which is shown, pressed onto the rollers 8 with its career.
  • a high-pressure control line 28 branches off from the pump work chamber 4, which leads to a control piston 29, which is of stepped design and is axially displaceably guided in a corresponding stepped bore 30, its end face of larger diameter, which is referred to here as control surface 31, facing the pump work chamber 4 .
  • its second end face of smaller diameter, here called working surface 32 delimits a section of stepped bore 30 which is closed by a solenoid valve 33 and is called working space 42.
  • the control piston 29 is loaded by a spring 34 in the direction of the control chamber 40.
  • the solenoid valve 33 is constructed so that it is "open when de-energized". As soon as the solenoid 35 of this solenoid valve 33 is energized, the movable valve member 36 is pulled onto the valve seat 37 and the working space 42 is closed. The functional surface 43 of the movable valve member 36 which is then acted upon from the working space and acts in the opening direction is smaller than the working surface 32 and determines the maximum opening cross section of the solenoid valve 33.
  • a solenoid valve 33 with a relatively small functional surface 43 or small valve seat 37 is sufficient, since corresponding to the area ratio on the control piston 29 for a specific control piston stroke to be controlled a desired volume upstream of the control surface 31, that is to say corresponding to a relatively large amount, only a relatively small amount has to flow out of the working space 42 via the valve seat 37.
  • an input 41 of a second relief channel 44 is controlled by the piston 39 of larger diameter of the control piston 29 assigned to the control surface 31, so that after the stroke movement of the control piston 29 the pump work chamber 4 is relieved of pressure towards the suction chamber 8. The consequence of this is that no pressure can build up in the pump work chamber 4 and the internal combustion engine is switched off.
  • the second embodiment of the invention shown in Fig. 2 is in principle similar to the first example, only with the difference that the control piston 29 'serves here as an escape piston and that the solenoid valve 33' is closed when de-energized.
  • the solenoid 35 'of the solenoid valve 33' is energized, the movable valve member 36 'lifts off from the valve seat 37' and the fuel under pressure in the pump work chamber moves the control piston 29 to the right, with fuel 32 from the work chamber 42 and through its working surface the relief channel 38 'is displaced to the pump suction chamber.
  • This fuel volume which is collected in the form of a store in front of the control surface 31, is then conveyed back to the pump work chamber 4 or via the latter and one of the pressure channels 6 to the internal combustion engine and there, after the high pressure phase in the pump work chamber 4 has been stopped, during the rest of the pump piston 1 or the subsequent suction stroke injected.
  • This quantity can also be supplemented by the controller on the pump side.
  • This procedure, a certain amount during the injection between storing is known as the so-called silent running method, because it extends the spraying time and thus makes the motor silent.
  • this volume to be controlled by the solenoid valve 33 in the working space 42 is only half as large as the original volume in the control space 40, the drain cross-section of the working space or the functional surface 43 of the solenoid valve can also be reduced accordingly, and so too to reduce closing forces acting on the valve member based on the pressure in the working space 42.
  • a gain in the direction of the opening time cross section can be achieved, that is to say one higher positioning speed of the control piston is achievable than in the known systems without a stepped piston design.
  • the invention is illustrated using a numerical example.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Fuel-Injection Apparatus (AREA)
  • High-Pressure Fuel Injection Pump Control (AREA)

Abstract

Hydraulic control device, especially for fuel injection pumps of internal-combustion engines, with a control passage (28) which branches off from a high-pressure space, for example a pump working space (4) and, in a control space (40), pressurises a control face (31) of a step piston (29) for hydraulic volume reduction, whose smaller-diameter working face delimits a closed working space () which has an outlet (38) controllable by a valve, with a functional face (43) on the movable valve member (36), said face determining the time/cross-section control and being pressurised by the working space (42). …<IMAGE>…

Description

Stand der TechnikState of the art

Die Erfindung geht aus von einer hydraulischen Steuer­einrichtung nach der Gattung des Hauptanspruchs. Bei hydraulischen Steuereinrichtungen, die mit ge­schlossenen flüssigkeitsgefüllten Räumen arbeiten und bei denen Kolben und Ventilflächen beaufschlagt werden, bewirkt der grundsätzliche Zusammenhang zwischen der flüssigkeitsbeaufschlagten Fläche und der aus den Flüssigkeitsdrücken und den Flächen herleitbaren Kräften immer dann Probleme, wenn der Faktor Zeit eine Rolle spielt. So kann die gleiche Kraft beispielsweise durch einen niederen Druck bei großer Fläche oder einen hohen Druck bei kleiner Fläche erzielt werden, wobei für den Faktor Zeit die Beherrschung des Volumens, d.h. die pro Zeit­einheit abfließende Menge maßgebend ist. Die zur Steuerung verwendeten Ventile sollen einerseits einen äußerst kurzen Öffnungs- und Schließzeitfaktor aufweisen und andererseits einen möglichst geringen Durchströmwiderstand, d.h. einen möglichst großen Steuerquerschnitt. Problematisch wird dann eine solche hydraulische Steuereinrichtung, wenn große Volumina von unter hohem Druck stehender Flüssigkeit in sehr kurzen Zeitabschnitten gesteuert werden sollen, wie es beispielsweise bei der Kraftstoffein­spritzung der Fall ist, bei der in weniger als einer Millisekunde und dieses sich mit der Drehzahl ändernd die Steuerung ablaufen muß.The invention relates to a hydraulic control device according to the preamble of the main claim. In the case of hydraulic control devices which work with closed liquid-filled rooms and in which pistons and valve surfaces are acted upon, the basic relationship between the surface exposed to the liquid and that of the liquid pressures and the surfaces results problems that can be derived when the time factor plays a role. The same force can be achieved, for example, by a low pressure in a large area or a high pressure in a small area, the mastery of the volume, ie the amount flowing off per unit of time, being decisive for the time factor. The valves used for control should on the one hand have an extremely short opening and closing time factor and on the other hand the lowest possible flow resistance, ie the largest possible control cross section. Such a hydraulic control device becomes problematic when large volumes of liquid under high pressure are to be controlled in very short time periods, as is the case, for example, with fuel injection, in which the speed changes in less than a millisecond and this changes Control must run.

Bei einer bekannten Kraftstoffeinspritzpumpe (De-­OS 29 25 418.0) kann die Kraftstoffeinspritzung unterbrochen werden, indem der Pumpenarbeitsraum über einen Entlastungskanal druckentlastet wird, wobei dieser Kanal über ein Magnetventil gesteuert wird. Das bewegliche Ventilglied des Magnetventils ist durch den Hochdruck des Pumpenarbeitsraums un­ mittelbar beaufschlagt, so daß bei geschlossenem Ventil entsprechend der in Öffnungsrichtung am beweg­lichen Ventilglied wirkenden Funktionsfläche erheb­liche Zuhaltekräfte aufgebracht werden müssen, solange kein Abströmen erfolgen soll. Bei einem stromlos geöffneten Magnetventil, wie es aus Sicherheits­gründen für einen solchen Zweck meist verwendet wird, ist der Energieverbrauch des Magneten propor­tional zu den erforderlichen Zuhaltekräften. Um den für die Steuerung erforderlichen Öffnungszeit­querschnitt zu erhalten, also einem Produkt aus Öffnungszeit und Öffnungsquerschnitt, muß meist bei den kurzen zur Verfügung stehenden Zeiten ein verhältnismäßig großer Querschnitt gewählt werden, was zu großen, teuren Magneten und entsprechend hohem Stromverbrauch führt.In a known fuel injection pump (De-OS 29 25 418.0), the fuel injection can be interrupted by relieving the pressure in the pump work space via a relief channel, this channel being controlled via a solenoid valve. The movable valve member of the solenoid valve is un because of the high pressure of the pump work space acted upon indirectly, so that when the valve is closed, considerable locking forces must be applied in accordance with the functional surface acting in the opening direction on the movable valve member, as long as no outflow is to take place. With a solenoid valve that is open when de-energized, as is usually used for such a purpose for safety reasons, the energy consumption of the magnet is proportional to the required locking forces. In order to obtain the opening time cross-section required for the control, i.e. a product of the opening time and opening cross-section, a relatively large cross-section must usually be selected with the short times available, which leads to large, expensive magnets and correspondingly high power consumption.

Bei einer anderen bekannten Kraftstoffeinspritzpumpe (Bosch-Pumpedüse) zweigt vom Pumpenarbeitsraum eine Druckleitung ab, über die der Kraftstoff einem Aus­weichkolben zugeführt wird, der immer dann durch den Förderdruck der Einspritzpumpe verschoben wird, wenn das Magneventil offen ist, wobei der auf der Rückseite des Ausweichkolbens vorhandene Raum durch das Magnetventil druckentlastet wird. Dieser Kolben ist durch eine Rückstellfeder belastet, die diesen beim Ausweichen aufnehmenden Kraftstoff gegen Ende der Einspritzung und nach Beendigung der Hochdruck­förderung über die Einspritzdüse in den Brennraum der Brennkraftmaschine einspritzt. Hierdurch wird eine Spritzdauerverlängerung und ein leiserer Lauf der Brennkraftmaschine erreicht. Auch bei dieser Pumpe steht das bewegliche Ventilglied des Magnet­ventils nahezu unter Förderdruck der Einspritz­pumpe, da dieser sehr hohe Druck nur durch die Kraft der Rückstellfeder verringert wird. Es müssen also auch hier hohe Schließkräfte aufgebracht werden, die entsprechend hohe Kosten bewirken und viel Raum und viel Energie beanspruchen.In another known fuel injection pump (Bosch pump nozzle), a pressure line branches off from the pump work space, via which the fuel is fed to an alternative piston, which is always displaced by the delivery pressure of the injection pump when the solenoid valve is open, the one on the rear of the alternative piston existing space is relieved of pressure by the solenoid valve. This piston is loaded by a return spring that this in the case of evasive fuel injected towards the end of the injection and after the end of the high-pressure delivery via the injection nozzle into the combustion chamber of the internal combustion engine. As a result, the spray duration is extended and the internal combustion engine runs quieter. In this pump too, the movable valve member of the solenoid valve is almost under the delivery pressure of the injection pump, since this very high pressure is reduced only by the force of the return spring. High clamping forces must also be applied here, which result in correspondingly high costs and take up a lot of space and a lot of energy.

Gleiches gilt grundsätzlich, wenn statt einem beweg­lichen Ventilglied eines Magnetventils ein mechanisch betätigter Steller verwendet wird.The same applies in principle if a mechanically operated actuator is used instead of a movable valve member of a solenoid valve.

Vorteile der ErfindungAdvantages of the invention

Die erfindungsgemäße hydraulische Steuerung mit den kennzeichnenden Merkmalen des Hauptanspruchs hat demgegenüber den Vorteil, daß das Flüssigkeits­volumen, das für eine bestimmte Verschiebung des Steuerkolbens innerhalb einer bestimmten Zeit das Ventil durchströmen muß, daß dieses Volumen gegenüber dem im Steuerkolben vorgelagerten, bei der Bewegung geschluckten Volumen um das Größenverhältnis Arbeits­fläche zu Steuerfläche verkleinert ist. Das heißt also, wenn die Steuerfläche doppelt so groß ist wie die Arbeitsfläche, so ist das Volumen, das durch das Ventil durchströmen muß, gerade halb so groß wie das der Steuerfläche nachströmende Volumen. Zwar steigt der Druck im Arbeitsraum gegenüber dem Steuerraumdruck umgekehrt proportional, d.h., daß der Druck im Arbeitsraum um das Verhältnis Steuer­fläche zu Arbeitsfläche größer ist als im Steuerraum. Dieser Druck im Arbeitsraum beaufschlagt wiederum das bewegliche Ventilglied des Ventils, so daß deren Schließkräfte diesem Druck angepaßt werden müssen. Aufgrund des Flächenverhältnisses zwischen Arbeits­fläche und Steuerfläche stark verkleinerten durch das Ventil zu steuernden Volumens kann auch entspre­chend der Öffnungsquerschnitt des Ventils verkleinert werden, wobei sich nunmehr vorteilhafterweise heraus­stellt, daß bei gleichbleibender Schließkraft durch die Verwendung des Stufenkolbens ein den Flächenver­hältnissen entsprechender Zeit-Querschnitts-Gewinn erzielbar ist. Der Vorteil läßt sich auch so beschrei­ben, daß aufgrund der Reduzierung des zu steuernden Volumens trotz der damit gegebenen Druckerhöhung bei gleichbleibender Schließkraft des beweglichen Ventilgliedes eine dem Flächenverhältnis entsprechen­ der Zeit-Öffnungsquerschnittsgewinn vorhanden ist, d.h. bei gleich großem Schließkraftaufwand am Ventil ist ein schnellerer Hub des Steuerkolbens erreich­bar oder umgekehrt für eine bestimmte Geschwindigkeit des Steuerkolbens genügt bei der Erfindung ein kleine­rer Öffnungsquerschnitt am Ventil.The hydraulic control according to the invention with the characterizing features of the main claim has the advantage that the liquid volume that has to flow through the valve for a certain displacement of the control piston within a certain time that this volume the upstream in the control piston, swallowed during the movement, is reduced by the size ratio of the working surface to the control surface. This means that if the control surface is twice as large as the working surface, the volume that has to flow through the valve is just half as large as the volume flowing through the control surface. The pressure in the work area increases inversely proportional to the control room pressure, ie the pressure in the work area is greater by the ratio of the control area to the work area than in the control room. This pressure in the working area in turn acts on the movable valve member of the valve, so that its closing forces must be adapted to this pressure. Due to the area ratio between the working area and the control area, the volume to be controlled by the valve can be greatly reduced, the opening cross section of the valve can also be reduced accordingly, it now advantageously being found that, with the closing force remaining the same, a time-cross-sectional gain corresponding to the area ratio can be achieved by using the stepped piston is. The advantage can also be described in such a way that, due to the reduction in the volume to be controlled, despite the increase in pressure which is given, while the closing force of the movable valve member remains the same, the area ratio corresponds the time opening cross-sectional gain is available, that is, with the same amount of closing force on the valve, a faster stroke of the control piston can be achieved or, conversely, for a certain speed of the control piston, a smaller opening cross section on the valve is sufficient in the invention.

Dieser Vorteil wirkt sich besonders bei Kraftstoffein­spritzpumpen für Brennkraftmaschinen aus, bei denen die Arbeitszyklen äußerst kurz sind - beispielsweise bei einer Vier-Zylinder-Brennkraftmaschine und 4000 U/min, was etwa 66 Arbeitszyklen des Ausweichkolbens pro Sekunde entspricht und dieses in Abhängigkeit von der Drehzahl veränderlich.This advantage has a particular effect on fuel injection pumps for internal combustion engines, in which the working cycles are extremely short - for example in a four-cylinder internal combustion engine and 4000 rpm, which corresponds to approximately 66 working cycles of the alternative piston per second and this varies depending on the speed .

Nach einer vorteilhaften Ausgestaltung der Erfindung dient als Steuerventil ein Magnetventil, so daß sich der Vorteil der Erfindung der nun geringer erforderlichen Stellkräfte besonders auswirkt, da der Aufwand zur Erzeugung einer Magnetkraft nicht nur im Bauvolumen, sondern auch in den Kosten über­proportional zur Stellkraftgröße wächst.According to an advantageous embodiment of the invention, a solenoid valve is used as the control valve, so that the advantage of the invention of the lower actuating forces required has a particular effect, since the effort for generating a magnetic force not only increases disproportionately to the actuating force size, but also in terms of costs.

Nach einer weiteren Ausgestaltung der Erfindung ist der Stufenkolben in Richtung Pumpenarbeitsraum federbelastet, so daß er nach Abbau des Druckes im Pumpenarbeitsraum automatisch wieder in eine Ausgangslage geschoben wird.According to a further embodiment of the invention, the stepped piston is spring-loaded in the direction of the pump work space, so that it is automatically pushed back into an initial position after the pressure in the pump work space has been reduced.

Erfindungsgemäß kann der Stufenkolben als Ausweich­kolben oder zur Steuerung eines Entlastungskanals dienen. Im ersten Fall wird der als Ausweichkolben arbeitende Steuerkolben, sobald das Ventil geöffnet ist, durch den Druck im Pumpenarbeitsraum entgegen der Rückstellkraft verschoben, wobei vor seiner Steuerfläche ein Volumen gespeichert wird, das dann gegen Ende der Einspritzung durch den Steuerkolben wieder zurückgefördert wird. Auch hier sind wieder zwei Varianten denkbar, nämlich daß diese Rückförde­rung direkt über das Einspritzventil zur Einspritzung führt oder daß diese Speichermenge durch den Regler der Einspritzpumpe für die Einspritzung ergänzt wird. In jedem Fall wird durch diese Einrichtung eine Spritzdauerverlängerung erreicht, was besonders im Leerlauf von Bedeutung ist, um dadurch einen Leiselauf der Maschine zu erreichen. Im anderen Fall, bei dem der Steuerkolben den Durchgang des Entlastungskanals steuert, wird erfindungsgemäß durch das kleine Steuerventil ein großer Abströmquer­schnitt am Steuerkolben gesteuert.According to the invention, the stepped piston can serve as an escape piston or for controlling a relief channel. In the first case, the control piston working as an evasive piston is displaced by the pressure in the pump work space against the restoring force as soon as the valve is open, a volume being stored in front of its control surface, which volume is then returned by the control piston towards the end of the injection. Again, two variants are conceivable, namely that this return leads directly to the injection via the injection valve or that this storage quantity is supplemented by the controller of the injection pump for injection. In any case, an extension of the spraying time is achieved by this device, which is particularly important when idling, in order to achieve quiet operation of the machine. In the other case, in which the control piston controls the passage of the relief channel, a large outflow cross section on the control piston is controlled according to the invention by the small control valve.

Weitere Vorteile und vorteilhafte Ausgestaltungen der Erfindung sind der nachfolgenden Beschreibung, der Zeichnung und den Ansprüchen entnehmbar.Further advantages and advantageous embodiments of the invention can be found in the following description, the drawing and the claims.

Zeichnungdrawing

Zwei Ausführungsbeispiele des Gegenstandes der Erfin­dung sind in der Zeichnung dargestellt und im folgen­den näher beschrieben. Es zeigen Fig. 1 eine Vertei­lereinspritzpumpe im Längsschnitt mit dem Stufenkolben als vorgesteuertes Ventil und Fig. 2 einen die Erfin­dung betreffenden Ausschnitt der Verteilerpumpe gemäß Fig. 1 mit dem Stufenkolben als Ausweichkolben in vergrößertem Maßstab.Two embodiments of the object of the invention are shown in the drawing and described in more detail below. 1 shows a distributor injection pump in longitudinal section with the step piston as a pilot-operated valve, and FIG. 2 shows a detail of the distributor pump according to FIG. 1 with the step piston as an evasive piston, on an enlarged scale.

Beschreibung der AusführungsbeispieleDescription of the embodiments

Bei der in Fig. 1 im Längsschnitt dargestellten Verteilereinspritzpumpe wird ein auch als Verteiler dienender Pumpenkolben 1 durch eine Antriebswelle 2 und mit Hilfe eines Nockengetriebes 3 in eine hin- und hergehende und gleichzeitig rotierende Bewegung versetzt. Bei jedem Druckhub des Pumpen­kolbens 1 wird dabei aus einem Pumpenarbeitsraum 4 über eine Verteilerlängsnut 5 Kraftstoff zu einem von mehreren Druckkanälen 6 gefördert, die um den Pumpenkolben 1 herum in gleichmäßigen Drehwinkel­abständen angeordnet sind und jeweils zu einem nicht dargestellten Brennraum einer Brennkraftmaschine führen.In the distributor injection pump shown in longitudinal section in FIG. 1, a pump piston 1, which also serves as a distributor, is set into a reciprocating and simultaneously rotating movement by a drive shaft 2 and with the aid of a cam gear 3. With each pressure stroke of the pump piston 1, fuel is conveyed from a pump working chamber 4 via a longitudinal distribution groove 5 to one of a plurality of pressure channels 6, which are arranged around the pump piston 1 at uniform angular intervals and each lead to a combustion chamber (not shown) of an internal combustion engine.

Der Pumpenarbeitsraum 4 wird über einen Saugkanal 7 aus einem im Gehäuse der Einspritzpumpe vorhandenen und mit Kraftstoff gefüllten Saugraum 8 mit Kraftstoff versorgt, indem während des Saughubs des Pumpenkolbens 1 der Saugkanal 7 durch im Pumpenkolben 1 vorgesehene Steuerlängsnuten 9 aufgesteuert wird. Die Anzahl der Steuernuten 9 entspricht der Anzahl der Druck­kanäle 6 und damit der Anzahl der pro Umdrehung des Pumpenkolbens ausgeführten Druckhübe.The pump work chamber 4 is supplied with fuel via a suction channel 7 from a suction chamber 8 which is present in the housing of the injection pump and is filled with fuel, in that the suction channel 7 is opened by longitudinal control grooves 9 provided in the pump piston 1 during the suction stroke of the pump piston 1. The number of control grooves 9 corresponds to the number of pressure channels 6 and thus to the number of pressure strokes carried out per revolution of the pump piston.

Die pro Hub in je einen der Druckkanäle 6 geförderte einzuspritzende Menge wird durch die axiale Lage eines um den Pumpenkolben 1 angeordneten Regelschie­bers 11 bestimmt. Diese axiale Lage wird durch einen Drehzahlregler 12 und einen willkürlich betätigbaren Verstellhebel 13 bestimmt unter Auswertung der jewei­ligen Drehzahl und Last (die Last kann beispielsweise der Stellung des Gaspedals des Kraftfahrzeugs ent­sprechen).The quantity to be injected per stroke into one of the pressure channels 6 is determined by the axial position of a slide valve 11 arranged around the pump piston 1. This axial position is determined by a speed controller 12 and an arbitrarily actuated adjusting lever 13, evaluating the respective speed and load (the load can correspond, for example, to the position of the accelerator pedal of the motor vehicle).

Der Saugraum 8 wird von einer Förderpumpe 14 her mit Kraftstoff versorgt, die durch die Antriebswelle 2 angetrieben wird und aus einem Kraftstoffbehälter 15 und einer Saugleitung 16 Kraftstoff zuführt. Durch ein Drucksteuerventil 17 wird der Ausgangs­druck der Förderpumpe 14 und damit der Druck im Saugraum 8 gesteuert, wobei dieser Druck mit zunehmen­ der Drehzahl entsprechend einer gewünschten Funktion ebenfalls zunimmt. Im Saugraum 8 sind der Nockentrieb 3 sowie der Drehzahlregler 12 angeordnet, die somit allseitig von diesem Druck beaufschlagt sind und von diesem Kraftstoff geschmiert werden.The suction chamber 8 is supplied with fuel by a feed pump 14, which is driven by the drive shaft 2 and supplies fuel from a fuel tank 15 and a suction line 16. The output pressure of the feed pump 14 and thus the pressure in the suction chamber 8 are controlled by a pressure control valve 17, this pressure also increasing the speed also increases according to a desired function. The cam drive 3 and the speed controller 12 are arranged in the suction chamber 8 and are thus acted upon on all sides by this pressure and are lubricated by this fuel.

Der Nockentrieb 3 weist einen Rollen 18 tragenden Rollenring 19 auf, der um einen bestimmten Winkel verdrehbar im Gehäuse gelagert ist und in dessen U-förmigen Querschnitt die Rollen 18 gelagert sind. Dieser Rollenring 19 ist über einen Verstellbolzen 21 mit einem Spritzverstellkolben 22 verdrehschlüssig gekoppelt, wobei in der Zeichnung dieser Spritzver­stellkolben 22 um 90° verdreht dargestellt ist, d. h. senkrecht zur Darstellungsebene arbeitet. In der Innenbohrung dieses Rollenrings 19 ist eine Klauenkupplung vorhanden, bei der antriebsseitige Klauen 23 der Antriebswelle 2 mit abtriebsseitigen Klauen 24 des Pump- und Verteilerkolbens 1 inein­andergreifen, so daß der Pump- und Verteilerkolben 1 unabhängig von der Antriebswelle 2 eine Hubbewegung während des Rotierens ausüben kann. Am Pumpenkolben 1 ist eine Stirnnockenscheibe 25 angeordnet, die mit ihrer Stirnnocken 26 aufweisenden Fläche auf den Rollen 18 abläuft, wobei die Zahl der Stirnnocken wiederum der Zahl der Druckkanäle 6 entspricht. Die Stirnnockenscheibe 25 wird durch Federn 27, von denen nur eine dargestellt ist, mit ihrer Laufbahn auf die Rollen 8 gepreßt.The cam drive 3 has a roller ring 19 carrying rollers 18, which is rotatably mounted in the housing by a certain angle and in the U-shaped cross section of which the rollers 18 are mounted. This roller ring 19 is coupled in a rotationally locking manner to an injection adjustment piston 22 via an adjustment bolt 21, this injection adjustment piston 22 being shown rotated by 90 ° in the drawing, ie working perpendicular to the plane of the illustration. In the inner bore of this roller ring 19 there is a claw coupling in which claws 23 on the drive side 2 of the drive shaft 2 mesh with claws 24 on the output side of the pumping and distributing piston 1, so that the pumping and distributing piston 1 independently of the drive shaft 2 exert a lifting movement while rotating can. An end cam disk 25 is arranged on the pump piston 1 and runs with its end cam 26 on the rollers 18, the number of end cams in turn corresponding to the number of pressure channels 6. The front cam disk 25 is supported by springs 27, only one of which is shown, pressed onto the rollers 8 with its career.

Vom Pumpenarbeitsraum 4 zweigt eine Hochdrucksteuer­leitung 28 ab, die zu einem Steuerkolben 29 führt, welcher stufenförmig ausgebildet ist und in einer entsprechenden Stufenbohrung 30 axial verschiebbar geführt ist, wobei seine Stirnfläche größeren Durch­messers, die hier mit Steuerfläche 31 bezeichnet wird, dem Pumpenarbeitsraum 4 zugewandt ist. Seine zweite Stirnfläche kleineren Durchmessers, hier Arbeitsfläche 32 bezeichnet, begrenzt hingegen einen Abschnitt der Stufenbohrung 30, der durch ein Magnet­ventil 33 verschlossen und als Arbeitsraum 42 bezeich­net ist. Außerdem ist der Steuerkolben 29 durch eine Feder 34 in Richtung Steuerraum 40 belastet.A high-pressure control line 28 branches off from the pump work chamber 4, which leads to a control piston 29, which is of stepped design and is axially displaceably guided in a corresponding stepped bore 30, its end face of larger diameter, which is referred to here as control surface 31, facing the pump work chamber 4 . In contrast, its second end face of smaller diameter, here called working surface 32, delimits a section of stepped bore 30 which is closed by a solenoid valve 33 and is called working space 42. In addition, the control piston 29 is loaded by a spring 34 in the direction of the control chamber 40.

Bei dem ersten in Fig. 1 dargestellten Ausführungsbei­spiel ist das Magnetventile 33 konstruktiv so aufge­baut, daß es "stromlos geöffnet" ist. Sobald die Magnetspule 35 dieses Magnetventils 33 erregt wird, wird das bewegliche Ventilglied 36 auf den Ventilsitz 37 gezogen und der Arbeitsraum 42 verschlossen. Die danach vom Arbeitsraum her beaufschlagte und in Öffnungsrichtung wirkende Funktionsfläche 43 des beweglichen Ventilgliedes 36 ist kleiner als die Arbeitsfläche 32 und bestimmt den maximalen Öffnungsquerschnitt des Magnetventils 33. Sobald die Magnetspule 35 elektrisch abgeschaltet wird, wird durch den im Pumpenarbeitsraum 4 herrschen­den und in den Steuerraum 40 übertragenden Hoch­druck der Steuerkolben 29 nach rechts verschoben, wobei der im Arbeitsraum 42 der Arbeitsfläche 32 vorgelagerte Kraftstoff am Ventilsitz 37 vorbei durch einen Entlastungskanal 38 zum Saugram 8 ver­drängt wird. Obwohl entsprechend der Stufenübersetzung von Steuerfläche zu Arbeitsfläche der Kraftstoffdruck im Arbeitsraum 42 entsprechend höher ist als im Steuerraum 40, genügt ein Magnetventil 33 mit ver­hältnismäßig kleiner Funktionsfläche 43 bzw. kleinem Ventilsitz 37, da entsprechend dem Flächenverhältnis am Steuerkolbens 29 für einen bestimmten zu steuernden Steuerkolbenhub entsprechend einem gewünschten, der Steuerfläche 31 vorgelagerten Volumen, also entsprechend einer verhältnismäßig großen Menge nur eine verhältnismäßig kleine Menge aus dem Arbeits­raum 42 über den Ventilsitz 37 strömen muß.In the first embodiment shown in Fig. 1, the solenoid valve 33 is constructed so that it is "open when de-energized". As soon as the solenoid 35 of this solenoid valve 33 is energized, the movable valve member 36 is pulled onto the valve seat 37 and the working space 42 is closed. The functional surface 43 of the movable valve member 36 which is then acted upon from the working space and acts in the opening direction is smaller than the working surface 32 and determines the maximum opening cross section of the solenoid valve 33. As soon as the magnetic coil 35 is electrically switched off, the high pressure prevailing in the pump work chamber 4 and transferring it into the control chamber 40 displaces the control piston 29 to the right, the fuel upstream in the work chamber 42 of the work surface 32 passing the valve seat 37 past a relief channel 38 to the Saugram 8 is ousted. Although the fuel pressure in the work chamber 42 is correspondingly higher than in the control chamber 40, corresponding to the step ratio from control surface to work surface, a solenoid valve 33 with a relatively small functional surface 43 or small valve seat 37 is sufficient, since corresponding to the area ratio on the control piston 29 for a specific control piston stroke to be controlled a desired volume upstream of the control surface 31, that is to say corresponding to a relatively large amount, only a relatively small amount has to flow out of the working space 42 via the valve seat 37.

Bei dem in Fig. 1 dargestellten Beispiel wird durch den der Steuerfläche 31 zugeordneten Kolben 39 größe­ren Durchmessers des Steuerkolbens 29 ein Eingang 41 eines zweiten Entlastungskanals 44 gesteuert, so daß nach der Hubbewegung des Steuerkolbens 29 der Pumpenarbeitsraum 4 zum Saugraum 8 hin druckent­lastet ist. Die Folge davon ist, daß sich im Pumpen­arbeitsraum 4 kein Druck aufbauen kann und die Brenn­kraftmaschine abgestellt wird.In the example shown in FIG. 1, an input 41 of a second relief channel 44 is controlled by the piston 39 of larger diameter of the control piston 29 assigned to the control surface 31, so that after the stroke movement of the control piston 29 the pump work chamber 4 is relieved of pressure towards the suction chamber 8. The consequence of this is that no pressure can build up in the pump work chamber 4 and the internal combustion engine is switched off.

Das in Fig. 2 dargestellte zweite Ausführungsbeispiel der Erfindung ist im Prinzip ähnlich aufgebaut wie das erste Beispiel, nur mit dem Unterschied, daß der Steuerkolben 29′ hier als Ausweichkolben dient und daß das Magnetventil 33′ stromlos geschlossen ist. Sobald die Magnetspule 35′ des Magnetventils 33′ erregt wird, hebt das bewegliche Ventilglied 36′ vom Ventilsitz 37′ ab und der im Pumpenarbeitsraum unter Druck stehende Kraftstoff verschiebt den Steuer­kolben 29 nach rechts, wobei durch seine Arbeitsfläche 32 Kraftstoff aus dem Arbeitsraum 42 und durch den Entlastungskanal 38′ zum Pumpensaugraum verdrängt wird. Dieses in Art eines Speichers vor der Steuer­fläche 31 gesammelte Kraftstoffvolumen wird dann nach Beendigung der Hochdruckphase im Pumpenarbeits­raum 4 während der Rast des Pumpenkolbens 1 oder des danach folgenden Saughubes zurück in den Pumpen­arbeitsraum 4 bzw. über diesen und einen der Druck­kanäle 6 zur Brennkraftmaschine gefördert und dort eingespritzt. Diese Menge kann auch durch den Regler pumpenseitig ergänzt werden. Dieses Verfahren, eine gewisse Menge während der Einspritzung zwischen­ zuspeichern, ist als sogenanntes Leiselaufverfahren bekannt, weil dadurch die Spritzdauer verlängert wird und damit ein Leiselauf des Motors erzielbar ist.The second embodiment of the invention shown in Fig. 2 is in principle similar to the first example, only with the difference that the control piston 29 'serves here as an escape piston and that the solenoid valve 33' is closed when de-energized. As soon as the solenoid 35 'of the solenoid valve 33' is energized, the movable valve member 36 'lifts off from the valve seat 37' and the fuel under pressure in the pump work chamber moves the control piston 29 to the right, with fuel 32 from the work chamber 42 and through its working surface the relief channel 38 'is displaced to the pump suction chamber. This fuel volume, which is collected in the form of a store in front of the control surface 31, is then conveyed back to the pump work chamber 4 or via the latter and one of the pressure channels 6 to the internal combustion engine and there, after the high pressure phase in the pump work chamber 4 has been stopped, during the rest of the pump piston 1 or the subsequent suction stroke injected. This quantity can also be supplemented by the controller on the pump side. This procedure, a certain amount during the injection between storing is known as the so-called silent running method, because it extends the spraying time and thus makes the motor silent.

Durch die Erfindung wird erreicht, daß diese Zwischen­speicherung infolge der Verwendung des erfindungsge­mäßen Steuerkolbens 29′ mit Hilfe eines normalen Magnetventils 33′ erzielbar ist. Die Untersetzung des Volumens vor der Steuerfläche 31 in Steuerraum 40 zu dem Volumen vor der Arbeitsfläche 32 im Arbeits­raum 42 bedingt für eine gewünschte Stellgeschwindig­keit des Steuerkolbens 29 einen bestimmten minimalen Öffnungsquerschnitt am Magnetventil 33, welcher durch die Funktionsfläche 43 festgelegt ist. Wenn also aufgrund der Untersetzungsverhältnisses dieses vom Magnetventil 33 zu steuernde Volumen im Arbeits­raum 42 nur halb so groß ist wie das ursprüngliche Volumen im Steuerraum 40, so kann entsprechend auch der Abflußquerschnitt des Arbeitsraums bzw. die Funktionsfläche 43 des Magnetventils verkleinert werden, um so auch die am Ventilglied angreifenden auf dem Druck im Arbeitsraum 42 beruhenden Schließ­kräfte zu verringern. Hierbei ergibt sich, daß je nach Untersetzungsverhältnis ein Gewinn in Richtung Öffnungszeitquerschnitt erreichbar ist, also eine höhere Stellgeschwindigkeit des Steuerkolbens erreich­bar ist als bei den bekannten Anlagen ohnen Stufenkol­benausführung.By the invention it is achieved that this intermediate storage due to the use of the control piston 29 'according to the invention with the help of a normal solenoid valve 33' can be achieved. The reduction of the volume in front of the control surface 31 in the control chamber 40 to the volume in front of the work surface 32 in the work space 42 requires a certain minimum opening cross section on the solenoid valve 33 for a desired actuating speed of the control piston 29, which is determined by the functional surface 43. If, due to the reduction ratio, this volume to be controlled by the solenoid valve 33 in the working space 42 is only half as large as the original volume in the control space 40, the drain cross-section of the working space or the functional surface 43 of the solenoid valve can also be reduced accordingly, and so too to reduce closing forces acting on the valve member based on the pressure in the working space 42. The result of this is that, depending on the reduction ratio, a gain in the direction of the opening time cross section can be achieved, that is to say one higher positioning speed of the control piston is achievable than in the known systems without a stepped piston design.

Anhand eines Zahlenbeispiels wird die Erfindung verdeutlicht. Die angenommenen Abmessungen sind: Stufenkolben Steuerfläche 39 D = 4 mm, Arbeitsfläche 32 d = 2 mm, Öffnungshub h = 0,4 mm.
Der Hochdruck (Pumpe) wird mit R = 100 bar angenommen, die auf die Steuerfläche 31 mit A = π·D²/4 = π·16/4 wirken.
Durch die Übersetzung D/d ergibt sich im Arbeitsraum 42 ein Druck auf die Arbeitsfläche 32 von 4·p = 400 bar.
Die Haltekraft am Magnetventil 33/36 wäre, wenn der Ventilsitz 37 beispielsweise auch einen Durch­messer von 2 mm hätte, F = A ·4p/4 = 125 N. Der Öffnungsquerschnitt D·π· h/2 = 4·π·0,4/2 ≈2,5 mm². Ohne Stufenkolben wäre der Öffnungsquerschnitt D·π·h = 4·π·0,4 ≈ 5 mm³.
Da der Druck im Arbeitsraum durch den Stufenkolben aber 4-fach vergrößert ist, ergibt sich eine ent­sprechend höhere Förderrate des verdrängenden Volu­mens, welches π·D²·x/4 ist, wobei x mit 3 mm ange­nommen wird.
Somit müßten nur (D/2)²·π·x/4 = V/4 = 12,5 mm³ aus dem Arbeitsraum verdrängt werden, um 50 mm³ Volumen beim Steuerraum zu gewinnen.The invention is illustrated using a numerical example. The assumed dimensions are: stepped piston control surface 39 D = 4 mm, working surface 32 d = 2 mm, opening stroke h = 0.4 mm.
The high pressure (pump) is assumed to be R = 100 bar, which act on the control surface 31 with A = π · D² / 4 = π · 16/4.
The translation D / d results in a pressure on the working surface 32 of 4 · p = 400 bar in the working space 42.
The holding force on the solenoid valve 33/36 would, if the valve seat 37 also had a diameter of 2 mm, for example, F = A4p / 4 = 125 N. The opening cross section D · π · h / 2 = 4 · π · 0.4 / 2 ≈2.5 mm². Without the stepped piston, the opening cross section would be D · π · h = 4 · π · 0.4 ≈ 5 mm³.
However, since the pressure in the work area is increased 4 times by the stepped piston, there is a correspondingly higher delivery rate of the displacing volume, which is π · D² · x / 4, where x is assumed to be 3 mm.
Thus, only (D / 2) ² · π · x / 4 = V / 4 = 12.5 mm³ would have to be displaced from the working area in order to gain 50 mm³ volume in the control room.

Die Relation ist also: 5 mm² Abströmquerschnitt für 50 mm³ Steuerraumvolumen, was mit dem Stufenkolben bei nur 2,5 mm² erreichbar ist. Hinzu kommt der Vorteil der höheren Ausströmgeschwindigkeit v. Da die Geschwindigkeit f√p entspricht, ergibt sich ein Vorteil bei v =f√4p Faktor 2, also doppelte Ausströmgeschwindigkeit.The relation is therefore: 5 mm² outflow cross-section for 50 mm³ control room volume, which can be achieved with the stepped piston at only 2.5 mm². Added to this is the advantage of the higher outflow speed v. Since the speed corresponds to f√p, there is an advantage at v = f√4 p Factor 2, i.e. double outflow speed.

Natürlich kann auch dadurch Einfluß genommen werden, daß der Sitzdurchmesser verkleinert und/oder der Öffnungshub geändert wird, jeweils mit entsprechendem Einfluß auf die Kenngrößen.Of course, it can also be influenced by reducing the seat diameter and / or changing the opening stroke, each with a corresponding influence on the parameters.

Da trotz höheren Drucks im Arbeitsraum 42 und damit vor dem beweglichen Ventilglied 36 wesentlich ge­ringere Stellkräfte erforderlich sind, ergibt sich dadurch eine bessere Beherrschung der Steuerung.Since considerably lower actuating forces are required in spite of higher pressure in the working space 42 and thus in front of the movable valve member 36, this results in better control of the control.

Alle in der Beschreibung, den nachfolgenden Ansprüchen und den Zeichnungen dargestellten Merkmale können sowohl einzeln als auch in beliebiger Kombination miteinander erfindungswesentlich sein.All of the features shown in the description, the following claims and the drawings can be essential to the invention both individually and in any combination with one another.

Claims (7)

1. Hydraulische Steuereinrichtung insbesondere für Kraftstoffeinspritzanlagen von Brennkraftmaschinen gekennzeichnet durch folgende Merkmale:
- einen in einer entsprechenden Gehäusebohrung (30) axial verschiebbar und radial dichtend geführ­ten Steuerkolben (29), dessen eine als Steuerfläche (31) dienende Stirnseite von in einem Steuerraum (40) unter höherem Druck stehender Flüssigkeit beaufschlagbar ist,
- einen von der Gehäusebohrung (30) und von der der Steuerfläche (31) abgewandte Stirnseite des Steuerkolbens (29) gebildeten Arbeitsfläche (32) begrenzten, flüssigkeitsgefüllten und abschließ­baren Arbeitsraum (42),
- einen steuerbaren Abfluß (38) dieses Arbeits­raums (42) zu einem flüssigkeitsgefüllten, unter niederem Druck stehenden Saugraum (8),
- ein Steuerventil (33) bestimmten maximalen Öff­nungsquerschnitts (9), in Form einer am beweglichen Ventilglied (36) in Öffnungsrichtung wirkenden, vom Arbeitsraum (42) her beaufschlagten Funktions­fläche (43) zur Zeit-Querschnitt-Steuerung,
- der Steuerkolben (29) ist als Stufenkolben und die Gehäusebohrung (30) ist als entsprechende Stufenbohrung ausgebildet
- und die Steuerfläche (31) wird durch die größere Stirnfläche und die Arbeitsfläche (32) durch die kleinere Stirnfläche gebildet.1. Hydraulic control device, in particular for fuel injection systems of internal combustion engines, characterized by the following features:
a control piston (29), which is axially displaceable and radially sealed in a corresponding housing bore (30), one end of which serves as a control surface (31) can be acted upon by liquid which is under higher pressure in a control chamber (40),
a working surface (32) which is delimited by the housing bore (30) and by the end face of the control piston (29) facing away from the control surface (31), is a liquid-filled and lockable working space (42),
a controllable outflow (38) of this working space (42) to a liquid-filled suction chamber (8) which is under low pressure,
a control valve (33) having a maximum opening cross section (9), in the form of a functional surface (43) acting on the movable valve member (36) in the opening direction and acted upon by the working space (42) for time cross-section control,
- The control piston (29) is designed as a stepped piston and the housing bore (30) is designed as a corresponding stepped bore
- And the control surface (31) is formed by the larger end surface and the working surface (32) by the smaller end surface. 2. Hydraulische Steuereinrichtung nach Anspruch 1, dadurch gekennzeichnet, daß das Verhältnis von Steuerfläche (31) zu Arbeitsfläche (32) gleich oder kleiner ist als das Verhältnis von Arbeitsfläche (32) zu Funktionsfläche (43).2. Hydraulic control device according to claim 1, characterized in that the ratio of the control surface (31) to the working surface (32) is equal to or smaller than the ratio of the working surface (32) to the functional surface (43). 3. Hydraulische Steuereinrichtung nach Anspruch 1 oder 2, gekennzeichnet durch die Anwendung in einer Kraftstoffeinspritzpumpe mit einem Pumpenarbeitsraum (4) begrenzenden Pumpenkolben (1) und mit mindestens einer vom Pumpenarbeitsraum (4) abzweigenden und in den Steuerraum (40) mündenden Hochdrucksteuerlei­tung (28), so daß die Ausweichbewegung des Steuer­kolbens (29) durch den Öffnungszeitquerschnitt des Steuerventils (33) bestimmbar ist.3. Hydraulic control device according to claim 1 or 2, characterized by the use in a fuel injection pump with a pump working chamber (4) delimiting pump piston (1) and with at least one of the pump working chamber (4) branching off and opening into the control chamber (40) high pressure control line (28) , so that the evasive movement of the control piston (29) can be determined by the opening time cross section of the control valve (33). 4. Kraftstoffeinspritzpumpe nach einem der vorhergehen­den Ansprüche, dadurch gekennzeichnet, daß als Steuerventil ein Magnetventil (33) dient.4. Fuel injection pump according to one of the preceding claims, characterized in that a solenoid valve (33) is used as the control valve. 5. Kraftstoffeinspritzpumpe nach einem der vorhergehen­den Ansprüche, dadurch gekennzeichnet, daß der Stufenkolben (29) in Richtung Pumpenarbeitsraum (4) durch eine Feder (34) belastet ist.5. Fuel injection pump according to one of the preceding claims, characterized in that the stepped piston (29) in the direction of the pump work chamber (4) is loaded by a spring (34). 6. Kraftstoffeinspritzpumpe nach einem der vorhergehen­den Ansprüche, dadurch gekennzeichnet, daß der Stufenkolben (29) mit seinem Abschnitt größeren Durchmessers einen Entlastungskanal (38) steuert.6. Fuel injection pump according to one of the preceding claims, characterized in that the stepped piston (29) controls a relief channel (38) with its section of larger diameter. 7. Kraftstoffeinspritzpumpe nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß der Stufenkolben (29′) mit seinem größeren Durchmesser als Speicher­kolben dient.7. Fuel injection pump according to one of claims 1 to 5, characterized in that the stepped piston (29 ') with its larger diameter serves as a storage piston.
EP89108081A 1988-06-11 1989-05-05 Hydraulic control device for fuel injection systems of internal combustion engines Withdrawn EP0346607A3 (en)

Applications Claiming Priority (2)

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DE3819996 1988-06-11
DE3819996A DE3819996A1 (en) 1988-06-11 1988-06-11 HYDRAULIC CONTROL DEVICE, IN PARTICULAR FOR FUEL INJECTION SYSTEMS OF INTERNAL COMBUSTION ENGINES

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EP0346607A2 true EP0346607A2 (en) 1989-12-20
EP0346607A3 EP0346607A3 (en) 1990-02-14

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EP89108081A Withdrawn EP0346607A3 (en) 1988-06-11 1989-05-05 Hydraulic control device for fuel injection systems of internal combustion engines

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US (1) US5007400A (en)
EP (1) EP0346607A3 (en)
JP (1) JPH0233462A (en)
DE (1) DE3819996A1 (en)

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DE3934953A1 (en) * 1989-10-20 1991-04-25 Bosch Gmbh Robert SOLENOID VALVE, ESPECIALLY FOR FUEL INJECTION PUMPS
DE3943299A1 (en) * 1989-12-29 1991-07-04 Bosch Gmbh Robert FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES
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EP0114375A2 (en) * 1983-01-25 1984-08-01 Klöckner-Humboldt-Deutz Aktiengesellschaft Fuel injection device for compression ignition internal combustion engines
GB2168130A (en) * 1984-11-30 1986-06-11 Lucas Ind Plc Electromagnetically operable valve
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EP0290797A2 (en) * 1987-05-11 1988-11-17 Robert Bosch Gmbh Fuel injection pump

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Also Published As

Publication number Publication date
JPH0233462A (en) 1990-02-02
DE3819996A1 (en) 1989-12-14
US5007400A (en) 1991-04-16
EP0346607A3 (en) 1990-02-14

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