EP0060344B1 - Fuel injection apparatus - Google Patents

Fuel injection apparatus Download PDF

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Publication number
EP0060344B1
EP0060344B1 EP19810110224 EP81110224A EP0060344B1 EP 0060344 B1 EP0060344 B1 EP 0060344B1 EP 19810110224 EP19810110224 EP 19810110224 EP 81110224 A EP81110224 A EP 81110224A EP 0060344 B1 EP0060344 B1 EP 0060344B1
Authority
EP
European Patent Office
Prior art keywords
armature
control
valve
fuel injection
fuel
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
Application number
EP19810110224
Other languages
German (de)
French (fr)
Other versions
EP0060344A3 (en
EP0060344A2 (en
Inventor
Karl Dipl.-Ing. Gmelin
Hans Dipl.-Ing. Kubach
Wolfgang Dr. Dipl.-Ing. Maisch
Klaus-Jürgen Ing. grad. Peters
Peter Ing. Grad. Schelhas
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
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Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP0060344A2 publication Critical patent/EP0060344A2/en
Publication of EP0060344A3 publication Critical patent/EP0060344A3/en
Application granted granted Critical
Publication of EP0060344B1 publication Critical patent/EP0060344B1/en
Expired 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
    • F02M69/00—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel
    • F02M69/16—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel characterised by means for metering continuous fuel flow to injectors or means for varying fuel pressure upstream of continuously or intermittently operated injectors
    • F02M69/26—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel characterised by means for metering continuous fuel flow to injectors or means for varying fuel pressure upstream of continuously or intermittently operated injectors the means varying fuel pressure in a fuel by-pass passage, the pressure acting on a throttle valve against the action of metered or throttled fuel pressure for variably throttling fuel flow to injection nozzles, e.g. to keep constant the pressure differential at the metering valve
    • 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
    • F02M69/00—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel
    • F02M69/46—Details, component parts or accessories not provided for in, or of interest apart from, the apparatus covered by groups F02M69/02 - F02M69/44
    • 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
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/20—Fuel-injection apparatus with permanent magnets
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/2278—Pressure modulating relays or followers

Definitions

  • the invention is based on a fuel injection system according to the preamble of the main claim.
  • a fuel injection system has already been proposed (DE-A 30 06 586 published 3.9.81), in which the pressure difference at metering valves can be changed in order to control the fuel-air mixture as a function of operating parameters of the internal combustion engine in that control valves are controlled by the pressure of a Hydraulic fluid can be influenced in a control pressure line, in which an electromagnetic control pressure valve, which can be controlled as a function of operating parameters of the internal combustion engine, is arranged in a nozzle-baffle plate design known per se (DE-A-2542726).
  • the control pressure line is connected via a throttle to the fuel injection system, in which a pressure relief valve for regulating the fuel pressure is arranged.
  • the disadvantage is that in addition to the high control power required for the control pressure valve, the characteristic curve of the control pressure valve cannot be influenced in the desired form.
  • a further disadvantage is that an interruption in the fuel supply when the internal combustion engine is in overrun
  • a non-prepublished DE-A-30 06 586 proposes a fuel injection system for mixed-compression spark-ignition internal combustion engines, with metering valves arranged in a fuel supply line for metering a fuel quantity in a certain ratio to the amount of air sucked in by the internal combustion engine, the metering being carried out at a constant, however
  • the pressure difference can be changed by moving the movable valve part of a control valve downstream of each metering valve and regulating the pressure difference on the metering valve on the one hand by the fuel pressure downstream of the respective metering valve and on the other hand by the pressure in a control pressure line, which can be acted upon by a control valve control pressure valve that can be controlled by operating parameters of the internal combustion engine and, on the other hand, is limited by a control throttle, d
  • the control pressure valve has a baffle plate coupled to an armature which is mounted against a return spring and which works together with a control valve seat which is connected to the fuel
  • the fuel injection system according to the invention with the characterizing features of the main claim has the advantage that a significantly lower control power is required to control the control pressure valve and the characteristic of the control pressure valve can be influenced in the desired form by the choice of the field strength of the permanent magnet.
  • control pressure valve is opened and the fuel injection is interrupted by reversing the direction of the excitation current of the electromagnet, for example when the internal combustion engine is in overrun mode.
  • FIG. 1 shows a fuel injection system with a control pressure valve
  • FIG. 2 shows a detailed illustration of a fuel metering valve
  • FIG. 3 shows a first exemplary embodiment of a control pressure valve
  • FIG. 4 shows a guide diaphragm of a control pressure valve according to FIG. 3
  • FIG. 5 shows a second exemplary embodiment of a control pressure valve
  • FIG. 6 shows a third exemplary embodiment of a Control pressure valves.
  • each cylinder of a mixture-compressing spark-ignition internal combustion engine not shown, being assigned a metering valve 1, to which a fuel quantity in a certain ratio to the air quantity sucked in by the internal combustion engine is metered.
  • the fuel injection system shown for example has four metering valves 1 and is therefore intended for a four-cylinder internal combustion engine.
  • the cross-section of the metering valves can, for example, be changed jointly, as indicated, by an actuating element 2 as a function of operating parameters of the internal combustion engine, for example in a known manner as a function of the amount of air drawn in by the internal combustion engine.
  • the metering valves 1 are located in a fuel supply line 3, into which fuel is conveyed from a fuel tank 6 by a fuel pump 5 driven by an electric motor 4.
  • a pressure limiting valve 9 is arranged in the fuel supply line 3, which pressure valve 9 in the fuel supply line 3 prevailing fuel pressure is limited and fuel can flow back into the fuel tank 6 when exceeded.
  • a line 11 Downstream of each metering valve 1, a line 11 is provided, via which the metered fuel reaches a control chamber 12 of a control valve 13 that is separately assigned to each metering valve 1.
  • the control chamber 12 of the control valve 13 is separated from a control chamber 15 of the control valve 13 by a movable valve part, for example a membrane 14.
  • the membrane 14 of the control valve 13 works together with a fixed valve seat 16 provided in the control chamber 12, via which the metered fuel can flow from the control chamber 12 to the individual injection valves 10, only one of which is shown, in the intake manifold of the internal combustion engine.
  • a control spring 17 is arranged in the control chamber 15, by means of which the membrane 14 is held on the valve seat 16 when the internal combustion engine is switched off.
  • a line 19 branches off from the fuel supply line 3 and opens into a control pressure line 21 via an electromagnetically actuated control pressure valve 20 in the manner of a nozzle-baffle plate.
  • the control chambers 15 of the control valves 13 are arranged downstream of the control pressure valve 20 in the control pressure line 21 and a control throttle 23 is arranged downstream of the control chambers 15. Fuel can flow from the control pressure line 21 into an outflow line 24 via the control throttle 23.
  • the control pressure valve 20 is controlled via an electronic control unit 32 as a function of the input operating parameters of the internal combustion engine, such as speed 33, throttle valve position 34, temperature 35, exhaust gas composition (oxygen probe) 36 and others.
  • the control of the control pressure valve 20 by the electronic control device 32 can take place in an analog or clocked manner.
  • the control pressure valve 20 can be designed by means of suitable spring forces or permanent magnets so that a pressure difference is established at the control pressure valve 20, which ensures that the internal combustion engine runs smoothly even if the electrical control fails.
  • the pressure relief valve 9 has a system pressure chamber 40 which is in communication with the fuel supply line 3 and is separated by a valve membrane 41 from a spring chamber 42 which is in communication with the atmosphere and in which a system pressure spring 43 is arranged which is in the closing direction of the valve acts on the valve membrane 41.
  • a valve seat 44 protrudes into the system pressure chamber 40, which cooperates with the valve membrane 41 and is axially displaceably mounted at an axial bearing point 45.
  • the end of the valve seat facing away from the valve membrane 41 projects out of the axial bearing point 45 into a collecting space 46 and is designed as a valve disk 47.
  • the valve plate 47 opens or closes a sealing seat 48, which can be designed as a rubber ring, via the fuel into a return flow line 49 and from there to the suction side of the fuel pump 5, e.g. the fuel tank 6 can flow back.
  • a closing compression spring 50 is supported on the valve plate 47, which acts on the valve plate 47 in the opening direction and tends to displace the valve seat 44 against the force acting on the valve seat 44 via the valve membrane 41.
  • a throttle gap 51 is provided in the axial bearing point 45 of the valve seat 44 between the system pressure chamber 40 and the collecting space 46. All fuel lines, for example the outflow line 24, via which fuel is to flow back to the fuel tank 6, open into the collecting space 46.
  • a channel 52 is provided in the valve seat 44, via which fuel can flow into the collecting space 46 when the valve membrane 41 is lifted off the valve seat 44.
  • the cross section of the valve plate 47 acted upon by fuel is smaller than the valve membrane cross section 41, and the elastic sealing seat 48 has approximately the same cross section as the valve plate 47.
  • the function of the pressure relief valve 9 is as follows: when the internal combustion engine is at a standstill, the valve plate 47 is seated on the sealing seat 48 and closes the return flow line 49, while the valve membrane 41 closes the valve seat 44.
  • the fuel pump 5 delivers fuel into the fuel supply line 3 and thus also into the system pressure chamber 40 of the pressure relief valve 9. If this pressure rises above a certain opening pressure at which the fuel pressure force on the valve membrane 41 and the spring force of the closing pressure spring 50 is greater than the spring force of the system compression spring 43 and the fuel pressure force on the valve plate 47, the valve plate 47 lifts off the sealing seat 48, and the valve seat 44 moves in the direction of the valve membrane 41.
  • valve membrane 41 lifts off the valve seat 44 and fuel can flow through the channel 52 into the collecting space 46 and from there into the return flow line 49.
  • the valve membrane 41 closes the valve seat 44.
  • FIG. 2 shows in detail a metering valve 1 which has a metering sleeve 55 in which a control slide 2 serving as an actuating element is axially displaceably mounted in a sliding bore 56.
  • the control slide 2 has a control groove 57 which is delimited on the one hand by a control edge 58. With an upward displacement movement, the control edge 58 opens more or fewer control openings 59, for example control slots, via which fuel can flow into the lines 11 in a measured manner.
  • an air measuring element (not shown) can act on an actuating end 60, for example in a known manner, and shift the control slide 2 as a function of the amount of air sucked in by the internal combustion engine.
  • a shoulder 61 is formed.
  • the actuating end 60 engages around a radial wall 62 and thus closes off the sliding bore 56 at the bottom.
  • An elastic sealing ring 63 is arranged on the radial wall 62, on which the shoulder 61 comes to rest in the rest position of the control slide 2 and thus seals against the outside.
  • a leakage space 64 is formed between the shoulder 61 and the radial wall 62, which catches the fuel leaking from the control groove 57 over the outer circumference of the control slide 2 and from which a leakage line 65 leads to the collecting space 46 of the pressure relief valve 9.
  • a line 67 branches off from the fuel supply line 3, which opens via a damping throttle 68 into a pressure chamber 69, into which the control slide 2 projects with an end face 70, which is formed at the end of the control slide 2 facing away from the actuating end 60.
  • FIG. 3 A first exemplary embodiment of a control pressure valve 20 is shown in FIG. 3.
  • a guide membrane 74 is clamped between a lower housing half 72 and an upper housing half 73, which is shown in a top view in FIG. With 75 an inflow opening is designated, which is connected to the line 19 and thus to the fuel supply line 3.
  • the inflow opening 75 opens via a vertically directed nozzle 76 serving as a control valve seat into a work space 77 enclosed by the lower housing half 72 and the upper housing half 73. From the work space 77, a drain opening 78, for example formed in the upper housing half 73, leads to the control pressure line 21
  • the guide membrane 74 has a clamping area 79 clamped between the two housing halves 72, 73.
  • a control area 80 is cut out of the guide membrane 74 and is connected on the one hand to a torsion area 81, while its other end is freely movable.
  • a spring area 82 is connected to the torsion area 81.
  • a compression spring 83 is supported on the one hand on the upper housing half 73 and on the other hand on the spring region 82 and presses this spring region against an adjusting screw 84 which is screwed into the lower housing half 72 and projects into the working space 77.
  • Axial adjustment of the adjusting screw 84 results in a corresponding pre-tensioning of the spring area 82, as a result of which the control area 80 is pressed more or less against the nozzle 76 protruding from the lower housing half 72 into the working space 77. In this way it can also be achieved that there is a disproportionate ratio between the pressure difference and the excitation current of the control pressure valve 20 in the case of larger regulated pressure differences.
  • the control area 80 serving as a baffle plate thus forms with the nozzle 76 a valve of the nozzle baffle plate type.
  • a disk-shaped armature 85 is arranged symmetrically to the torsion region 81 forming a torsion axis and is connected to the control region 80.
  • the armature 85 penetrates through an opening 87 in the control area 80 with an extension 86, while a further extension 88 of the armature on the other side of the torsion region 81 projects through an opening 89.
  • the spring-elastic bearing is almost frictionless, so that hysteresis is avoided.
  • a pole piece 90 is inserted into the lower housing half 72 and projects into the working space 77 aligned with the extension 86 of the armature 85, while a further pole shoe 91 is likewise arranged in the lower housing half 72 and aligned with the extension 88 of the armature 85 into the working space 77 protrudes.
  • An air gap 92 is formed between the pole piece 90 and the shoulder 86 and an air gap 93 between the shoulder 88 and the pole shoe 91.
  • a pole shoe 94 is arranged in the upper housing half 73, projecting into the working space 77, and in alignment with the pole shoe 91, a pole shoe 95.
  • an air gap 97 is formed, and an air gap 98 is formed between the pole shoe 95 and the end face 96.
  • an electromagnetic coil 99 is arranged which encompasses the housing halves 72, 73.
  • a fork-shaped guide body 100 engages around the electromagnetic coil 99 and bears on the one hand on the pole shoes 94, 95 outside the upper housing half 73 and on the other hand. on a permanent magnet 101 on which, on the other hand, a guide body 102 acts, which engages around the electromagnet coil 99 in a fork-like manner on the lower housing half 72 and acts on the pole shoes 90, 91.
  • a pressure difference between the nozzle 76 and the control area 80 is adjusted in accordance with the voltage specified via the adjusting screw 84 and the spring area 82 at the control area 80, which pressure difference is sufficient for fuel metering in normal operation or for emergency operation of the internal combustion engine in the event of failure of the electronic control unit 32 allowed.
  • the guide bodies 100 and 102 are magnetically polarized by the permanent magnet 101, so that for example the magnetic field of the permanent magnet 101 on the one hand by the guide body '100 via over the pole piece 95, the air gap 98, the armature 85, the air gap 93, the pole piece 91 to the guide body 102 runs and on the other hand over the pole piece 94, the air gap 97, the armature 85, the air gap 92, the pole piece 90 to the guide body 102.
  • an electromagnetic field is built up in a certain direction, for example on the one hand from Pole shoe 95 via the air gap 98, the armature 85, the air gap 97 to the pole shoe 94 and, on the other hand, from the pole shoe 91 via the air gap 93 to the armature 85 and via the air gap 92 to the pole shoe 90.
  • the magnetic flow of the electromagnetic field and permanent field runs in the air gaps 92 and 98 each in the same direction, so they add up, while the magnetic fields of electromagnet and permanent magnet in the air gaps 93 and 97 run in the opposite direction so that they subtract.
  • control pressure valve 20 has the advantage that a substantially lower control power of the electromagnetic circuit is required by superimposing a permanent magnetic circuit with an electromagnetic circuit.
  • control region 80 opens the nozzle 76 to such an extent that there is almost no pressure difference at the nozzle 76, as a result of the addition of the force of the closing spring 17 and the fuel pressure force in the control chamber 15 close the control valves 13.
  • control signals characterizing the pushing operation of the internal combustion engine for example speed above idle speed and throttle valve closed, the desired interruption of the fuel injection can be achieved by lowering the electrical power for the control pressure valve 20 by reversing the current.
  • the edge region 103 of the control region 80 can be made so soft that, in particular with large pivoting movements of the armature 85, that is to say with large regulated pressure differences, as a result of the increase in the magnetic force when the armature 85 approaches the pole shoes 90, 95 results in a disproportionate increase in the differential pressure with the excitation current.
  • a guide membrane 74 ' is stretched, with which a cup-shaped guide body 104 is connected, the bottom of which, facing the nozzle 76, serves as a baffle plate 105.
  • a cylinder-shaped armature 106 is connected to the guide body 104 which is axially movable on the guide membrane 74 '.
  • the clamping plane of the guide membrane 74 ' lies approximately in the direction of a resulting radial force acting on the armature 106.
  • a first air gap 110 is formed in the axial direction between a first end face 107 of the armature 106 and an end face 108 of a core 109, while between a facing second end face 111 and a guide piece 112, which is connected on the one hand to the lower housing half 72 and on the other hand via the engages second end face 111, a second axial air gap 113 is formed.
  • the permanent magnet 101 Arranged within the core 109 is the permanent magnet 101, which projects into the armature 106 with a pole piece 114 such that, for example, the magnetic flux of the permanent magnet 101 in the first air gap 110 is directed opposite the magnetic flux generated by the electromagnetic coil 99, while in the second air gap 113 the magnetic flux of the permanent magnet 101 and the magnetic flux generated by the electromagnetic coil 99 run in the same direction.
  • An antimagnetic tube 116 which is supported on the one hand on a collar 115 of the lower housing half 72 and on the other hand on the core 109, serves to seal the electromagnetic coil 99 from the fuel.
  • a pin 117 on the pole piece 114 for example conically shaped det, can engage in a corresponding recess 118 of the guide body 104 and is used for guiding the armature 106 as centrally as possible.
  • the upper housing half 73 can have a weak point 119 which, when the upper housing half 73 is axially loaded, for adjusting the gap between the baffle plate 105 and the Nozzle 76 can be deformed axially.
  • the second exemplary embodiment according to FIG. 5 also offers the advantages already mentioned above for the exemplary embodiment according to FIG. 3 by superimposing a permanent magnet system.
  • a guide diaphragm 74 ′′ is clamped in the lower housing half 72 and is fixed with a cylindrical armature 106 ′′ in is connected to its central region, which partially overlaps the guide membrane 74 ′′ with an edge 120.
  • the edge 120 has a first end face 107 ", between which and a end face 108" of the core 109 "a first air gap 110" is formed.
  • a baffle plate 105 is formed on the armature 106" facing away from the permanent magnet 101 and cooperates with the nozzle 76.
  • the pole piece 114 "of the permanent magnet 101 projects into the armature 106" and is tapered toward the armature 106 "and largely magnetically saturated. As a result, the radial forces are reduced with tolerance-related eccentricities and the armature mass can be minimized.
  • the magnetic flux of the permanent magnet 101 in the first air gap 110 ′′ runs in the opposite direction to the magnetic flux of the magnetic flux generated by the electromagnetic coil 99, while in the second air gap 113 ′′ both magnetic fluxes run in the same direction.
  • the exemplary embodiment according to FIG. 6 has the advantages as have already been described for the two previous exemplary embodiments.
  • the forces of the return spring on the armature on the one hand and of the permanent magnet on the other hand can be matched to one another in such a way that the pressure difference regulated by the control pressure valves 20, 20 ', 20 "is theoretically independent of the hydraulic flow.

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

Description

Die Erfindung geht aus von einer Kraftstoffeinspritzanlage nach der Gattung des Hauptanspruchs. Es ist schon eine Kraftstoffeinspritzanlage vorgeschlagen worden (DE-A 30 06 586 veröffentlicht 3.9.81), bei der zur Steuerung des Kraftstoff-Luft-Gemisches in Abhängigkeit von Betriebskenngrössen der Brennkraftmaschine die Druckdifferenz an Zumessventilen dadurch änderbar ist, dass Regelventile durch den Druck einer Druckflüssigkeit in einer Steuerdruckleitung beeinflusst werden, in der ein in Abhängigkeit von Betriebskenngrössen der Brennkraftmaschine ansteuerbares elektromagnetisches Steuerdruckventil in an sich bekannter Düse-Prallplatte-Bauart (DE-A-2542726) angeordnet ist. Die Steuerdruckleitung ist über eine Drossel mit der Kraftstoffeinspritzanlage verbunden, in der ein Druckbegrenzungsventil zur Regelung des Kraftstoffdruckes angeordnet ist. Nachteilig ist dabei, dass neben einer hohen für das Steuerdruckventil erforderlichen Ansteuerleistung die Kennlinie des Steuerdruckventils nicht in gewünschter Form beeinflussbar ist. Weiterhin nachteilig ist, dass eine Unterbrechung der Kraftstoffzufuhr im Schiebebetrieb der Brennkraftmaschine einen zusätzlichen Aufwand erfordert.The invention is based on a fuel injection system according to the preamble of the main claim. A fuel injection system has already been proposed (DE-A 30 06 586 published 3.9.81), in which the pressure difference at metering valves can be changed in order to control the fuel-air mixture as a function of operating parameters of the internal combustion engine in that control valves are controlled by the pressure of a Hydraulic fluid can be influenced in a control pressure line, in which an electromagnetic control pressure valve, which can be controlled as a function of operating parameters of the internal combustion engine, is arranged in a nozzle-baffle plate design known per se (DE-A-2542726). The control pressure line is connected via a throttle to the fuel injection system, in which a pressure relief valve for regulating the fuel pressure is arranged. The disadvantage here is that in addition to the high control power required for the control pressure valve, the characteristic curve of the control pressure valve cannot be influenced in the desired form. A further disadvantage is that an interruption in the fuel supply when the internal combustion engine is in overrun mode requires additional effort.

Im einzelnen ist in der nichtvorveröffentlichten DE-A-30 06 586 eine Kraftstoffeinspritzanlage für gemischverdichtende fremdgezündete Brennkraftmaschinen vorgeschlagen, mit in einer Kraftstoffversorgungsleitung angeordneten Zumessventilen zur Zumessung einer zur von der Brennkraftmaschine angesaugten Luftmenge in einem bestimmten Verhältnis stehenden Kraftstoffmenge, wobei die Zumessung bei konstanter, jedoch in Abhängigkeit von Betriebskenngrössen der Brennkraftmaschine änderbarer Druckdifferenz erfolgt, indem das bewegliche Ventilteil eines stromabwärts jedes Zumessventiles angeordneten und die Druckdifferenz am Zumessventil jeweils regelnden Regelventiles einerseits vom Kraftstoffdruck stromabwärts des jeweiligen Zumessventiles und andererseits vom Druck in einer Steuerdruckleitung beaufschlagbar ist, die einerseits durch ein in Abhängigkeit von Betriebskenngrössen der Brennkraftmaschine ansteuerbares Steuerdruckventil und andererseits durch eine Steuerdrossel begrenzt wird, wobei das Steuerdruckventil eine mit einem entgegen einer Rückstellfeder gelagerten Anker gekoppelte Prallplatte hat, die mit einem Steuerventilsitz zusammenarbeitet, der mit der Kraftstoffversorgungsleitung in Verbindung steht und über den in geöffnetem Zustand Kraftstoff gedrosselt in die Steuerdruckleitung gelangt. Der Anker liegt hier in einem Permanentmagnetfeld zu dem quer ein Elektromagnetfeld verläuft. Das Elektromagnetfeld und das Permanentmagnetfeld verlaufen hier also nicht teilweise in gleicher und teilweise in entgegengesetzter Richtung.Specifically, a non-prepublished DE-A-30 06 586 proposes a fuel injection system for mixed-compression spark-ignition internal combustion engines, with metering valves arranged in a fuel supply line for metering a fuel quantity in a certain ratio to the amount of air sucked in by the internal combustion engine, the metering being carried out at a constant, however Depending on the operating parameters of the internal combustion engine, the pressure difference can be changed by moving the movable valve part of a control valve downstream of each metering valve and regulating the pressure difference on the metering valve on the one hand by the fuel pressure downstream of the respective metering valve and on the other hand by the pressure in a control pressure line, which can be acted upon by a control valve control pressure valve that can be controlled by operating parameters of the internal combustion engine and, on the other hand, is limited by a control throttle, d The control pressure valve has a baffle plate coupled to an armature which is mounted against a return spring and which works together with a control valve seat which is connected to the fuel supply line and via which, in the open state, fuel is throttled into the control pressure line. The armature is here in a permanent magnetic field to which an electromagnetic field extends. The electromagnetic field and the permanent magnetic field here do not run partly in the same and partly in the opposite direction.

Vorteile der ErfindungAdvantages of the invention

Die erfindungsgemässe Kraftstoffeinspritzanlage mit den kennzeichnenden Merkmalen des Hauptanspruchs hat demgegenüber den Vorteil, dass zur Ansteuerung des Steuerdruckventiles eine wesentlich geringere Ansteuerleistung erforderlich und die Kennlinie des Steuerdruckventiles in gewünschter Form durch die Wahl der Feldstärke des Permanentmagneten beeinflussbar ist. Als weiterer Vorteil ist anzusehen, dass die Kennlinie des erfindungsgemässen Steuerdruckventiles bei einem Erregerstrom von I = O mit einer endlichen Steigung beginnt und ein Notbetrieb der Kraftstoffeinspritzanlage bei Stromausfall möglich ist, da hierbei durch das Steuerdruckventil eine mittlere Druckdifferenz geregelt wird. Vorteilhaft ist ebenfalls, dass das erfindungsgemässe Steuerdruckventil nicht zu einer Druckpulsation führt.In contrast, the fuel injection system according to the invention with the characterizing features of the main claim has the advantage that a significantly lower control power is required to control the control pressure valve and the characteristic of the control pressure valve can be influenced in the desired form by the choice of the field strength of the permanent magnet. A further advantage is that the characteristic curve of the control pressure valve according to the invention begins with a finite slope at an excitation current of I = O and emergency operation of the fuel injection system is possible in the event of a power failure, since a mean pressure difference is regulated by the control pressure valve. It is also advantageous that the control pressure valve according to the invention does not lead to a pressure pulsation.

Durch die in den Unteransprüchen aufgeführten Massnahmen sind vorteilhafte Weiterbildungen und Verbesserungen der im Hauptanspruch angegebenen Kraftstoffeinspritzanlage möglich. Besonders vorteilhaft ist, dass durch Umkehr der Richtung des Erregerstromes des Elektromagneten das Steuerdruckventil geöffnet und die Kraftstoffeinspritzung unterbrochen wird, beispielsweise im Schiebebetrieb der Brennkraftmaschine.The measures listed in the subclaims permit advantageous developments and improvements of the fuel injection system specified in the main claim. It is particularly advantageous that the control pressure valve is opened and the fuel injection is interrupted by reversing the direction of the excitation current of the electromagnet, for example when the internal combustion engine is in overrun mode.

Zeichnungdrawing

Ausführungsbeispiele der Erfindung sind in der Zeichnung vereinfacht dargestellt und in der nachfolgenden Beschreibung näher erläutert. Es zeigen Figur 1 eine Kraftstoffeinspritzanlage mit einem Steuerdruckventil, Figur 2 eine detalliertere Darstellung eines Kraftstoffzumessventiles, Figur 3 ein erstes Ausführungsbeispiel eines Steuerdruckventiles, Figur 4 eine Führungsmembran eines Steuerdruckventiles nach Figur 3, Figur 5 ein zweites Ausführungsbeispiel eines Steuerdruckventiles, Figur 6 ein drittes Ausführungsbeispiel eines Steuerdruckventiles.Embodiments of the invention are shown in simplified form in the drawing and explained in more detail in the following description. 1 shows a fuel injection system with a control pressure valve, FIG. 2 shows a detailed illustration of a fuel metering valve, FIG. 3 shows a first exemplary embodiment of a control pressure valve, FIG. 4 shows a guide diaphragm of a control pressure valve according to FIG. 3, FIG. 5 shows a second exemplary embodiment of a control pressure valve, and FIG. 6 shows a third exemplary embodiment of a Control pressure valves.

Beschreibung der AusführungsbeispieleDescription of the embodiments

Bei dem in Figur 1 dargestellten Ausführungsbeispiel einer Kraftstoffeinspritzanlage sind mit 1 Zumessventile dargestellt, wobei jedem Zylinder einer nichtdargestellten gemischverdichtenden fremdgezündeten Brennkraftmaschine ein Zumessventil 1 zugeordnet ist, an dem eine zur von der Brennkraftmaschine angesaugten Luftmenge in einem bestimmten Verhältnis stehende Kraftstoffmenge zugemessen wird. Die beispielsweise dargestellte Kraftstoffeinspritzanlage weist vier Zumessventile 1 auf und ist somit für eine Vierzylinder-Brennkraftmaschine bestimmt. Der Querschnitt der Zumessventile ist beispielsweise gemeinsam, wie angedeutet, durch ein Betätigungselement 2 in Abhängigkeit von Betriebskenngrössen der Brennkraftmaschine änderbar, beispielsweise in bekannter Weise in Abhängigkeit von der durch die Brennkraftmaschine angesaugten Luftmenge. Die Zumessventile 1 liegen in einer Kraftstoffversorgungsleitung 3, in die von einer durch einen Elektromotor 4 angetriebenen Kraftstoffpumpe 5 aus einem Kraftstoffbehälter 6 Kraftstoff gefördert wird. In der Kraftstoffversorgungsleitung 3 ist ein Druckbegrenzungsventil 9 angeordnet, das den in der Kraftstoffversorgungsleitung 3 herrschenden Kraftstoffdruck begrenzt und bei Überschreiten Kraftstoff in den Kraftstoffbehälter 6 zurückfliessen lässt.In the exemplary embodiment of a fuel injection system shown in FIG. 1, 1 metering valves are shown, with each cylinder of a mixture-compressing spark-ignition internal combustion engine, not shown, being assigned a metering valve 1, to which a fuel quantity in a certain ratio to the air quantity sucked in by the internal combustion engine is metered. The fuel injection system shown for example has four metering valves 1 and is therefore intended for a four-cylinder internal combustion engine. The cross-section of the metering valves can, for example, be changed jointly, as indicated, by an actuating element 2 as a function of operating parameters of the internal combustion engine, for example in a known manner as a function of the amount of air drawn in by the internal combustion engine. The metering valves 1 are located in a fuel supply line 3, into which fuel is conveyed from a fuel tank 6 by a fuel pump 5 driven by an electric motor 4. A pressure limiting valve 9 is arranged in the fuel supply line 3, which pressure valve 9 in the fuel supply line 3 prevailing fuel pressure is limited and fuel can flow back into the fuel tank 6 when exceeded.

Stromabwärts jedes Zumessventiles 1 ist eine Leitung 11 vorgesehen, über die der zugemessene Kraftstoff in eine Regelkammer 12 eines jedem Zumessventil 1 gesondert zugeordneten Regelventiles 13 gelangt. Die Regelkammer 12 des Regelventiles 13 ist durch ein beispielsweise als Membran 14 ausgebildetes bewegliches Ventilteil von einer Steuerkammer 15 des Regelventiles 13 getrennt. Die Membran 14 des Regelventiles 13 arbeitet mit einem in der Regelkammer 12 vorgesehenen festen Ventilsitz 16 zusammen, über den der zugemessene Kraftstoff aus der Regelkammer 12 zu den einzelnen Einspritzventilen 10, von denen nur eines dargestellt ist, im Saugrohr der Brennkraftmaschine strömen kann. In der Steuerkammer 15 ist eine Schliessfeder 17 angeordnet, durch die bei abgestellter Brennkraftmaschine die Membran 14 am Ventilsitz 16 gehalten wird.Downstream of each metering valve 1, a line 11 is provided, via which the metered fuel reaches a control chamber 12 of a control valve 13 that is separately assigned to each metering valve 1. The control chamber 12 of the control valve 13 is separated from a control chamber 15 of the control valve 13 by a movable valve part, for example a membrane 14. The membrane 14 of the control valve 13 works together with a fixed valve seat 16 provided in the control chamber 12, via which the metered fuel can flow from the control chamber 12 to the individual injection valves 10, only one of which is shown, in the intake manifold of the internal combustion engine. A control spring 17 is arranged in the control chamber 15, by means of which the membrane 14 is held on the valve seat 16 when the internal combustion engine is switched off.

Von der Kraftstoffversorgungsleitung 3 zweigt eine Leitung 19 ab, die über ein elektromagnetisch betätigbares Steuerdruckventil 20 in Düse-Prallplatte-Bauart in eine Steuerdruckleitung 21 mündet. Stromabwärts des Steuerdruckventiles 20 sind in der Steuerdruckleitung 21 die Steuerkammern 15 der Regelventile 13 und stromabwärts der Steuerkammern 15 ist eine Steuerdrossel 23 angeordnet. Über die Steuerdrossel 23 kann Kraftstoff aus der Steuerdruckleitung 21 in eine Abströmleitung 24 strömen. Die Ansteuerung des Steuerdruckventiles 20 erfolgt über ein elektronisches Steuergerät 32 in Abhängigkeit von entsprechend eingegebenen Betriebskenngrössen der Brennkraftmaschine wie Drehzahl 33, Drosselklappenstellung 34, Temperatur 35, Abgaszusammensetzung (Sauerstoffsonde) 36 und anderen. Die Ansteuerung des Steuerdruckventiles 20 durch das elektronische Steuergerät 32 kann dabei analog oder getaktet erfolgen. Bei nicht erregtem Zustand des Steuerdruckventiles 20 kann durch geeignete Federkräfte oder Permanentmagneten das Steuerdruckventil 20 so ausgelegt sein, dass sich am Steuerdruckventil 20 eine Druckdifferenz einstellt, die auch bei Ausfallen der elektrischen Ansteuerung einen Notlauf der Brennkraftmaschine gewährleistet.A line 19 branches off from the fuel supply line 3 and opens into a control pressure line 21 via an electromagnetically actuated control pressure valve 20 in the manner of a nozzle-baffle plate. The control chambers 15 of the control valves 13 are arranged downstream of the control pressure valve 20 in the control pressure line 21 and a control throttle 23 is arranged downstream of the control chambers 15. Fuel can flow from the control pressure line 21 into an outflow line 24 via the control throttle 23. The control pressure valve 20 is controlled via an electronic control unit 32 as a function of the input operating parameters of the internal combustion engine, such as speed 33, throttle valve position 34, temperature 35, exhaust gas composition (oxygen probe) 36 and others. The control of the control pressure valve 20 by the electronic control device 32 can take place in an analog or clocked manner. When the control pressure valve 20 is not energized, the control pressure valve 20 can be designed by means of suitable spring forces or permanent magnets so that a pressure difference is established at the control pressure valve 20, which ensures that the internal combustion engine runs smoothly even if the electrical control fails.

Das Druckbegrenzungsventil 9 weist eine Systemdruckkammer 40 auf, die mit der Kraftstoffversorgungsleitung 3 in Verbindung steht und durch eine Ventilmembran 41 von einer Federkammer 42 getrennt ist, die mit der Atmosphäre in Verbindung steht und in der eine Systemdruckfeder 43 angeordnet ist, die in Schliessrichtung des Ventils die Ventilmembran 41 beaufschlagt. In die Systemdruckkammer 40 ragt ein Ventilsitz 44, der mit der Ventilmembran 41 zusammenwirkt und an einer Axiallagerstelle 45 axial verschiebbar gelagert ist. Das der Ventilmembran 41 abgewandte Ende des Ventilsitzes ragt andererseits aus der Axiallagerstelle 45 heraus in einen Sammelraum 46 und ist als Ventilteller 47 ausgebildet. Der Ventilteller 47 öffnet oder schliesst einen Dichtsitz 48, der als Gummiring ausgebildet sein kann, über den Kraftstoff in eine Rückströmleitung 49 und von dort auf die Saugseite der Kraftstoffpumpe 5, z.B. den Kraftstoffbehälter 6 zurückströmen kann. An dem Ventilteller 47 stützt sich eine Schliessdruckfeder 50 ab, die den Ventilteller 47 in Öffnungsrichtung beaufschlagt und bestrebt ist, den Ventilsitz 44 entgegen der über die Ventilmembran 41 auf den Ventilsitz 44 wirkenden Kraft zu verschieben. In der Axiallagerstelle 45 des Ventilsitzes 44 zwischen der Systemdruckkammer 40 und dem Sammelraum 46 ist ein Drosselspalt 51 vorgesehen. In den Sammelraum 46 münden alle Kraftstoffleitungen, beispielsweise die Abströmleitung 24, über die Kraftstoff zum Kraftstoffbehälter 6 zurückströmen soll. So ist in dem Ventilsitz 44 ein Kanal 52 vorgesehen, über den bei vom Ventilsitz 44 abgehobener Ventilmembran 41 Kraftstoff in den Sammelraum 46 strömen kann. Der von Kraftstoff beaufschlagte Querschnitt des Ventiltellers 47 ist geringer, als der Ventilmembranquerschnitt 41, und der elastische Dichtsitz 48 hat in etwa den gleichen Querschnitt wie der Ventilteller 47.The pressure relief valve 9 has a system pressure chamber 40 which is in communication with the fuel supply line 3 and is separated by a valve membrane 41 from a spring chamber 42 which is in communication with the atmosphere and in which a system pressure spring 43 is arranged which is in the closing direction of the valve acts on the valve membrane 41. A valve seat 44 protrudes into the system pressure chamber 40, which cooperates with the valve membrane 41 and is axially displaceably mounted at an axial bearing point 45. The end of the valve seat facing away from the valve membrane 41, on the other hand, projects out of the axial bearing point 45 into a collecting space 46 and is designed as a valve disk 47. The valve plate 47 opens or closes a sealing seat 48, which can be designed as a rubber ring, via the fuel into a return flow line 49 and from there to the suction side of the fuel pump 5, e.g. the fuel tank 6 can flow back. A closing compression spring 50 is supported on the valve plate 47, which acts on the valve plate 47 in the opening direction and tends to displace the valve seat 44 against the force acting on the valve seat 44 via the valve membrane 41. A throttle gap 51 is provided in the axial bearing point 45 of the valve seat 44 between the system pressure chamber 40 and the collecting space 46. All fuel lines, for example the outflow line 24, via which fuel is to flow back to the fuel tank 6, open into the collecting space 46. Thus, a channel 52 is provided in the valve seat 44, via which fuel can flow into the collecting space 46 when the valve membrane 41 is lifted off the valve seat 44. The cross section of the valve plate 47 acted upon by fuel is smaller than the valve membrane cross section 41, and the elastic sealing seat 48 has approximately the same cross section as the valve plate 47.

Die Funktion des Druckbegrenzungsventils 9 ist folgende: Bei stillstehender Brennkraftmaschine sitzt der Ventilteller 47 auf dem Dichtsitz 48 auf und verschliesst die Rückströmleitung 49, während die Ventilmembran 41 den Ventilsitz 44 verschliesst. Beim Starten der Brennkraftmaschine fördert die Kraftstoffpumpe 5 Kraftstoff in die Kraftstoffversorgungsleitung 3 und damit auch in die Systemdruckkammer 40 des Druckbegrenzungsventils 9. Steigt dieser Druck über einen bestimmten Öffnungsdruck, bei dem die Kraftstoffdruckkraft auf die Ventilmembran 41 und die Federkraft der Schliessdruckfeder 50 grösser ist, als die Federkraft der Systemdruckfeder 43 und die Kraftstoffdruckkraft auf den Ventilteller 47, so hebt der Ventilteller 47 von dem Dichtsitz 48 ab, und der Ventilsitz 44 verschiebt sich in Richtung zur Ventilmembran 41. Diese Verschiebebewegung wird begrenzt durch einen Anschlag 53, an dem der Ventilteller 47 zum Anliegen kommt. Wird nun ein nur noch durch die Federkraft der Systemdruckfeder 43 bestimmter Kraftstoffdruck (Systemdruck) erreicht, so hebt die Ventilmembran 41 von dem Ventilsitz 44 ab und Kraftstoff kann über den Kanal 52 in den Sammelraum 46 und von dort in die Rückströmleitung 49 abströmen. Beim Abstellen der Brennkraftmaschine bzw. der Unterbrechung der Kraftstofförderung durch die Kraftstoffpumpe 5 verschliesst die Ventilmembran 41 den Ventilsitz 44. Die Federkräfte der Systemdruckfeder 43 und der Schliessdruckfeder 50 und die von Kraftstoff beaufschlagten Querschnitte der Ventilmembran 41 und des Ventiltellers 47 sind so aufeinander abgestimmt, dass nun zunächst weiterhin über den Drosselspalt 51 Kraftstoff in den Sammelraum 46 und aus dem Sammelraum 46 über den Dichtsitz 48 in die Rückströmleitung 49 abströmen kann, bis der Kraftstoffdruck in der Kraftstoffeinspritzanlage geringer ist, als der zur Öffnung der Einspritzventile 10 erforderliche Kraftstoffdruck. Erst unterhalb des zur Öffnung der Einspritzventile 10 erforderlichen Kraftstoffdruckes wird der Ventilteller 47 so weit entgegen der Kraft der Schliessdruckfeder 50 verschoben, dass er auf dem Dichtsitz 48 die Rückströmleitung 49 absperrend zum Aufliegen kommt. Durch den im Sammelraum 46 herrschenden Kraftstoffdruck wird nun der Ventilteller 47 zusätzlich auf den Dichtsitz 48 gepresst. Hierdurch wird ein Auslecken von Kraftstoff aus der Kraftstoffeinspritzanlage verhindert, so dass bei einem erneuten Start der Brennkraftmaschine die Kraftstoffeinspritzanlage in kürzester Zeit einsatzfähig ist. Wird nun die Brennkraftmaschine erneut gestartet, so ist der erforderliche Öffnungsdruck, bei dem der Ventilteller 47 von dem Dichtsitz 48 abhebt, grösser, als der zum Schliessen erforderliche Druck, da am Ventilteller 47 im geschlossenen Zustand kein Kräfteausgleich der vom Kraftstoffdruck im Sammelraum 46 bewirkten Druckkräfte erfolgt. Ein gegenüber dem Schliessdruck erhöhter Öffnungsdruck ist jedoch erwünscht, um ein sicheres Schliessen zu gewährleisten, auch wenn nach dem Abstellen der Brennkraftmaschine durch Erwärmung des eingeschlossenen Kraftstoffes der Kraftstoffdruck in der Kraftstoffeinspritzanlage ansteigt.The function of the pressure relief valve 9 is as follows: when the internal combustion engine is at a standstill, the valve plate 47 is seated on the sealing seat 48 and closes the return flow line 49, while the valve membrane 41 closes the valve seat 44. When the internal combustion engine is started, the fuel pump 5 delivers fuel into the fuel supply line 3 and thus also into the system pressure chamber 40 of the pressure relief valve 9. If this pressure rises above a certain opening pressure at which the fuel pressure force on the valve membrane 41 and the spring force of the closing pressure spring 50 is greater than the spring force of the system compression spring 43 and the fuel pressure force on the valve plate 47, the valve plate 47 lifts off the sealing seat 48, and the valve seat 44 moves in the direction of the valve membrane 41. This displacement movement is limited by a stop 53 on which the valve plate 47 comes to the concern. If a fuel pressure (system pressure) determined only by the spring force of the system compression spring 43 is now reached, the valve membrane 41 lifts off the valve seat 44 and fuel can flow through the channel 52 into the collecting space 46 and from there into the return flow line 49. When the internal combustion engine is switched off or the fuel supply is interrupted by the fuel pump 5, the valve membrane 41 closes the valve seat 44. The spring forces of the system compression spring 43 and the closing compression spring 50 and the cross sections of the valve membrane 41 and the valve disk 47 acted upon by fuel are coordinated with one another in such a way that Now fuel can continue to flow via the throttle gap 51 into the collecting space 46 and from the collecting space 46 via the sealing seat 48 into the return flow line 49 until the fuel pressure in the fuel injection system is lower than the fuel pressure required to open the injection valves 10. Only below the fuel pressure required to open the injection valves 10 is the valve disc 47 so far against the force of the Closing compression spring 50 shifted so that it comes to rest on the sealing seat 48 to shut off the return flow line 49. Due to the fuel pressure prevailing in the collecting space 46, the valve plate 47 is now additionally pressed onto the sealing seat 48. This prevents fuel from leaking out of the fuel injection system, so that when the internal combustion engine is started again, the fuel injection system can be used in the shortest possible time. If the internal combustion engine is now started again, the required opening pressure at which the valve plate 47 lifts off the sealing seat 48 is greater than the pressure required for closing, since in the closed state there is no force equalization of the pressure forces caused by the fuel pressure in the collecting space 46 in the closed state he follows. However, an opening pressure that is higher than the closing pressure is desirable in order to ensure reliable closing, even if the fuel pressure in the fuel injection system rises after the internal combustion engine is switched off due to the heating of the enclosed fuel.

In Figur 2 ist detallierter ein Zumessventil 1 dargestellt, das eine Zumesshülse 55 aufweist, in der in einer Gleitbohrung 56 ein als Betätigungselement dienender Steuerschieber 2 axial verschiebbar gelagert ist. Der Steuerschieber 2 hat eine Steuernut 57, die einerseits durch eine Steuerkante 58 begrenzt wird. Bei einer Verschiebebewegung nach oben öffnet die Steuerkante 58 mehr oder weniger Steueröffnungen 59, beispielsweise Steuerschlitze, über die Kraftstoff zugemessen in die Leitungen 11 abströmen kann. An der Betätigungsseite des Steuerschiebers 2 kann an einem Betätigungsende 60 beispielsweise in bekannter Weise ein nicht dargestelltes Luftmessorgan angreifen und den Steuerschieber 2 in Abhängigkeit von der von der Brennkraftmaschine angesaugten Luftmenge verschieben. Am Übergang zum Betätigungsende 60 mit geringerem Querschnitt wird ein Absatz 61 gebildet. Das Betätigungsende 60 umgreift eine radiale Wandung 62 und schliesst somit die Gleitbohrung 56 nach unten ab. An der radialen Wandung 62 ist ein elastischer Dichtring 63 angeordnet, auf dem der Absatz 61 in Ruhestellung des Steuerschiebers 2 zum Anliegen kommt und somit nach aussen hin abdichtet. In Arbeitsstellung des Steuerschiebers 2 wird zwischen dem Absatz 61 und der radialen Wandung 62 ein Leckraum 64 gebildet, der den aus der Steuernut 57 über den Aussenumfang des Steuerschiebers 2 leckenden Kraftstoff auffängt und von dem eine Leckleitung 65 zum Sammelraum 46 des Druckbegrenzungsventils 9 führt. Die der auf das Betätigungsende 60 wirkenden Betätigungskraft entgegenwirkende Kraft wird durch Kraftstoff erzeugt. Hierfür zweigt von der Kraftstoffversorgungsleitung 3 eine Leitung 67 ab, die über eine Dämpfungsdrossel 68 in einen Druckraum 69 mündet, in den der Steuerschieber 2 mit einer Stirnfläche 70 ragt, die an dem dem Betätigungsende 60 abgewandten Ende des Steuerschiebers 2 ausgebildet ist.FIG. 2 shows in detail a metering valve 1 which has a metering sleeve 55 in which a control slide 2 serving as an actuating element is axially displaceably mounted in a sliding bore 56. The control slide 2 has a control groove 57 which is delimited on the one hand by a control edge 58. With an upward displacement movement, the control edge 58 opens more or fewer control openings 59, for example control slots, via which fuel can flow into the lines 11 in a measured manner. On the actuating side of the control slide 2, an air measuring element (not shown) can act on an actuating end 60, for example in a known manner, and shift the control slide 2 as a function of the amount of air sucked in by the internal combustion engine. At the transition to the actuating end 60 with a smaller cross section, a shoulder 61 is formed. The actuating end 60 engages around a radial wall 62 and thus closes off the sliding bore 56 at the bottom. An elastic sealing ring 63 is arranged on the radial wall 62, on which the shoulder 61 comes to rest in the rest position of the control slide 2 and thus seals against the outside. In the working position of the control slide 2, a leakage space 64 is formed between the shoulder 61 and the radial wall 62, which catches the fuel leaking from the control groove 57 over the outer circumference of the control slide 2 and from which a leakage line 65 leads to the collecting space 46 of the pressure relief valve 9. The force counteracting the actuation force acting on the actuation end 60 is generated by fuel. For this purpose, a line 67 branches off from the fuel supply line 3, which opens via a damping throttle 68 into a pressure chamber 69, into which the control slide 2 projects with an end face 70, which is formed at the end of the control slide 2 facing away from the actuating end 60.

Ein erstes Ausführungsbeispiel eines Steuerdruckventiles 20 ist in Figur 3 dargestellt. Dabei ist zwischen eine untere Gehäusehälfte 72 und eine obere Gehäusehälfte 73 eine Führungsmembran 74 eingespannt, die in Figur 4 in einer Draufsicht dargestellt ist. Mit 75 ist eine Zuflussöffnung bezeichnet, die mit der Leitung 19 und damit mit der Kraftstoffversorgungsleitung 3 in Verbindung steht. Die Zuflussöffnung 75 mündet über eine vertikal gerichtete, als Steuerventilsitz dienende Düse 76 in einen von der unteren Gehäusehälfte 72 und der oberen Gehäusehälfte 73 umschlossenen Arbeitsraum 77. Von dem Arbeitsraum 77 führt eine Abflussöffnung 78, beispielsweise in der oberen Gehäusehälfte 73 ausgebildet, zur Steuerdruckleitung 21. Die Führungsmembran 74 weist einen zwischen den beiden Gehäusehälften 72, 73 eingespannten Einspannbereich 79 auf. Aus der Führungsmembran 74 ist ein Steuerbereich 80 ausgespart, der einerseits mit einem Torsionsbereich 81 verbunden ist, während sein anderes Ende frei bewegbar ist. Dem Steuerbereich 80 abgewandt ist ein ebenfalls aus der Führungsmembran 74 ausgesparter Federbereich 82 mit dem Torsionsbereich 81 verbunden. Eine Druckfeder 83 stützt sich einerseits an der oberen Gehäusehälfte 73 und andererseits an dem Federbereich 82 ab und drückt diesen Federbereich gegen eine Einstellschraube 84, die in die untere Gehäusehälfte 72 eingeschraubt ist und in den Arbeitsraum 77 ragt. Durch axiales Verstellen der Einstellschraube 84 erfolgt eine entsprechende Vorspannung des Federbereiches 82, wodurch der Steuerbereich 80 mehr oder weniger gegen die aus der unteren Gehäusehälfte 72 in den Arbeitsraum 77 ragende Düse 76 gepresst wird. Hierdurch lässt sich auch erreichen, dass bei grösseren geregelten Druckdifferenzen ein überproportionales Verhältnis zwischen Druckdifferenz und Erregerstrom des Steuerdruckventiles 20 besteht. Der als Prallplatte dienende Steuerbereich 80 bildet somit mit der Düse 76 ein Ventil nach der Düsen-Prallplatte-Bauart. Symmetrisch zu dem eine Torsionsachse bildenden Torsionsbereich 81 ist ein scheibenförmiger Anker 85 angeordnet und mit dem Steuerbereich 80 verbunden. Dabei durchgreift der Anker 85 mit einem Ansatz 86 einen Durchbruch 87 im Steuerbereich 80, während ein weiterer Ansatz 88 des Ankers andererseits des Torsionsbereiches 81 einen Durchbruch 89 durchragt. Die federelastische Lagerung ist nahezu reibungsfrei, so dass Hysterese vermieden wird. In die untere Gehäusehälfte 72 ist ein Polschuh 90 eingesetzt und ragt auf den Ansatz 86 des Ankers 85 ausgerichtet in den Arbeitsraum 77, während ein weiterer Polschuh 91 ebenfalls in der unteren Gehäusehälfte 72 angeordnet ist und auf den Ansatz 88 des Ankers 85 ausgerichtet in den Arbeitsraum 77 ragt. Zwischen dem Polschuh 90 und dem Ansatz 86 wird ein Luftspalt 92 und zwischen dem Ansatz 88 und dem Polschuh 91 ein Luftspalt 93 gebildet. Fluchtend zum Polschuh 90 ist in der oberen Gehäusehälfte 73 ein Polschuh 94 in den Arbeitsraum 77 ragend angeordnet und fluchtend zu dem Polschuh 91 ein Polschuh 95. Zwischen dem Polschuh 94 und der zugewandten Stirnfläche 96 des Ankers 85 wird ein Luftspalt 97 und zwischen dem Polschuh 95 und der Stirnfläche 96 ein Luftspalt 98 gebildet. Zwischen den Polschuhen 90 und 91 und andererseits 94 und 95 ist eine die Gehäusehälften 72, 73 umgreifende Elektromagnetspule 99 angeordnet. Ein gabelförmig ausgebildeter Leitkörper 100 umgreift die Elektromagnetspule 99 und liegt einerseits an den Polschuhen 94, 95 ausserhalb der oberen Gehäusehälfte 73 an und andererseits. an einem Permanentmagneten 101, an dem andererseits ein Leitkörper 102 angreift, der gabelförmig an der unteren Gehäusehälfte 72 die Elektromagnetspule 99 umgreift und an den Polschuhen 90,91 angreift. In nicht erregtem Zustand der Elektromagnetspule 99 wird entsprechend der über die Einstellschraube 84 und den Federbereich 82 an dem Steuerbereich 80 vorgegebenen Spannung zwischen der Düse 76 und dem Steuerbereich 80 eine Druckdifferenz eingeregelt, die eine ausreichende Kraftstoffzumessung im Normalbetrieb oder für einen Notlauf der Brennkraftmaschine bei Ausfall des elektronischen Steuergerätes 32 erlaubt. Die Leitkörper 100 und 102 werden durch den Permanentmagneten 101 magnetisch polarisiert, so dass beispielsweise das Magnetfeld des Permanentmagneten 101 einerseits von dem Leitkörper '100 über über den Polschuh 95, den Luftspalt 98, den Anker 85, den Luftspalt 93, den Polschuh 91 zum Leitkörper 102 verläuft und andererseits über den Polschuh 94, den Luftspalt 97, den Anker 85, den Luftspalt 92, den Polschuh 90 zum Leitkörper 102. Wird nun ein Erregerstrom der Elektromagnetspule 99 zugeführt, so baut sich ein Elektromagnetfeld in bestimmter Richtung auf, z.B. einerseits vom Polschuh 95 über den Luftspalt 98, den Anker 85, den Luftspalt 97 zum Polschuh 94 und andererseits vom Polschuh 91 über den Luftspalt 93 zum Anker 85 und über den Luftspalt 92 zum Polschuh 90. Hierbei verläuft der magnetische Fluss von Elektromagnetfeld und Permanentfeld in den Luftspalten 92 und 98 jeweils in gleicher Richtung, sie addieren sich also, während die Magnetfelder von Elektromagnet und Permanentmagnet in den Luftspalten 93 und 97 entgegengerichtet verlaufen, so dass sie sich subtrahieren. Hierdurch wird der Ansatz 86 des Ankers 85 stärker zum Polschuh 90 und das andere Ende des Ankers 85 stärker zum Polschuh 95 gezogen, wodurch der Steuerbereich 80 um den Torsionsbereich 81 geschwenkt mehr die Düse 76 verschlisst, so dass ein höherer Differenzdruck geregelt wird. Das erfindungsgemässe Steuerdruckventil 20 hat den Vorteil, dass durch Überlagerung eines Permanentmagnetkreises mit einem Elektromagnetkreis eine wesentlich geringere Ansteuerleistung des Elektromagnetkreises erforderlich ist. Ausserdem kann durch entsprechende Schwächung oder Verstärkung des Permanentmagneten 101 die Steuerkennlinie des Steuerdruckventiles 20 in gewünschter Weise beeinflusst werden und die Kennlinie des Steuerdruckventiles 20 für einen Erregerstrom I = O beginnt mit einer endlichen Steigung. Bei Umkehr der Richtung des Erregerstromes ergibt sich ein zusätzlicher Vorteil dadurch, dass der Steuerbereich 80 die Düse 76 so weit öffnet, dass an der Düse 76 nahezu keine Druckdifferenz mehr auftritt, wodurch infolge der Addition der Kraft der Schliessfeder 17 und der Kraftstoffdruckkraft in der Steuerkammer 15 die Regelventile 13 schliessen. Hierdurch lässt sich beim Vorliegen von den Schiebebetrieb der Brennkraftmaschine kennzeichnenden Steuersignalen, z.B. Drehzahl oberhalb Leerlaufdrehzahl und Drosselklappe geschlossen bei geringerer elektrischer Leistung für das Steuerdruckventil 20 durch Stromumkehr ein gewünschtes Unterbrechen der Kraftstoffeinspritzung erreichen.A first exemplary embodiment of a control pressure valve 20 is shown in FIG. 3. A guide membrane 74 is clamped between a lower housing half 72 and an upper housing half 73, which is shown in a top view in FIG. With 75 an inflow opening is designated, which is connected to the line 19 and thus to the fuel supply line 3. The inflow opening 75 opens via a vertically directed nozzle 76 serving as a control valve seat into a work space 77 enclosed by the lower housing half 72 and the upper housing half 73. From the work space 77, a drain opening 78, for example formed in the upper housing half 73, leads to the control pressure line 21 The guide membrane 74 has a clamping area 79 clamped between the two housing halves 72, 73. A control area 80 is cut out of the guide membrane 74 and is connected on the one hand to a torsion area 81, while its other end is freely movable. Averted from the control area 80, a spring area 82, likewise recessed from the guide membrane 74, is connected to the torsion area 81. A compression spring 83 is supported on the one hand on the upper housing half 73 and on the other hand on the spring region 82 and presses this spring region against an adjusting screw 84 which is screwed into the lower housing half 72 and projects into the working space 77. Axial adjustment of the adjusting screw 84 results in a corresponding pre-tensioning of the spring area 82, as a result of which the control area 80 is pressed more or less against the nozzle 76 protruding from the lower housing half 72 into the working space 77. In this way it can also be achieved that there is a disproportionate ratio between the pressure difference and the excitation current of the control pressure valve 20 in the case of larger regulated pressure differences. The control area 80 serving as a baffle plate thus forms with the nozzle 76 a valve of the nozzle baffle plate type. A disk-shaped armature 85 is arranged symmetrically to the torsion region 81 forming a torsion axis and is connected to the control region 80. The armature 85 penetrates through an opening 87 in the control area 80 with an extension 86, while a further extension 88 of the armature on the other side of the torsion region 81 projects through an opening 89. The spring-elastic bearing is almost frictionless, so that hysteresis is avoided. A pole piece 90 is inserted into the lower housing half 72 and projects into the working space 77 aligned with the extension 86 of the armature 85, while a further pole shoe 91 is likewise arranged in the lower housing half 72 and aligned with the extension 88 of the armature 85 into the working space 77 protrudes. An air gap 92 is formed between the pole piece 90 and the shoulder 86 and an air gap 93 between the shoulder 88 and the pole shoe 91. In alignment with the pole shoe 90, a pole shoe 94 is arranged in the upper housing half 73, projecting into the working space 77, and in alignment with the pole shoe 91, a pole shoe 95. Between the pole shoe 94 and the facing end face 96 of the armature 85, an air gap 97 is formed, and an air gap 98 is formed between the pole shoe 95 and the end face 96. Between the pole pieces 90 and 91 and on the other hand 94 and 95, an electromagnetic coil 99 is arranged which encompasses the housing halves 72, 73. A fork-shaped guide body 100 engages around the electromagnetic coil 99 and bears on the one hand on the pole shoes 94, 95 outside the upper housing half 73 and on the other hand. on a permanent magnet 101 on which, on the other hand, a guide body 102 acts, which engages around the electromagnet coil 99 in a fork-like manner on the lower housing half 72 and acts on the pole shoes 90, 91. In the de-energized state of the electromagnetic coil 99, a pressure difference between the nozzle 76 and the control area 80 is adjusted in accordance with the voltage specified via the adjusting screw 84 and the spring area 82 at the control area 80, which pressure difference is sufficient for fuel metering in normal operation or for emergency operation of the internal combustion engine in the event of failure of the electronic control unit 32 allowed. The guide bodies 100 and 102 are magnetically polarized by the permanent magnet 101, so that for example the magnetic field of the permanent magnet 101 on the one hand by the guide body '100 via over the pole piece 95, the air gap 98, the armature 85, the air gap 93, the pole piece 91 to the guide body 102 runs and on the other hand over the pole piece 94, the air gap 97, the armature 85, the air gap 92, the pole piece 90 to the guide body 102. If an excitation current is now supplied to the electromagnetic coil 99, an electromagnetic field is built up in a certain direction, for example on the one hand from Pole shoe 95 via the air gap 98, the armature 85, the air gap 97 to the pole shoe 94 and, on the other hand, from the pole shoe 91 via the air gap 93 to the armature 85 and via the air gap 92 to the pole shoe 90. The magnetic flow of the electromagnetic field and permanent field runs in the air gaps 92 and 98 each in the same direction, so they add up, while the magnetic fields of electromagnet and permanent magnet in the air gaps 93 and 97 run in the opposite direction so that they subtract. As a result, the shoulder 86 of the armature 85 is pulled more strongly towards the pole shoe 90 and the other end of the armature 85 more strongly towards the pole shoe 95, as a result of which the control region 80, pivoted about the torsion region 81, wears out the nozzle 76 so that a higher differential pressure is regulated. The control pressure valve 20 according to the invention has the advantage that a substantially lower control power of the electromagnetic circuit is required by superimposing a permanent magnetic circuit with an electromagnetic circuit. In addition, the control characteristic of the control pressure valve 20 can be influenced in a desired manner by appropriate weakening or reinforcement of the permanent magnet 101 and the characteristic of the control pressure valve 20 for an excitation current I = O begins with a finite slope. When the direction of the excitation current is reversed, there is an additional advantage in that the control region 80 opens the nozzle 76 to such an extent that there is almost no pressure difference at the nozzle 76, as a result of the addition of the force of the closing spring 17 and the fuel pressure force in the control chamber 15 close the control valves 13. In this way, when control signals characterizing the pushing operation of the internal combustion engine are present, for example speed above idle speed and throttle valve closed, the desired interruption of the fuel injection can be achieved by lowering the electrical power for the control pressure valve 20 by reversing the current.

An dem Durchbruch 87 der Führungsmembran 74 kann der Randbereich 103 des Steuerbereiches 80 so weich ausgeführt werden, dass sich insbesondere bei grossen Schwenkbewegungen des Ankers 85, also bei grossen geregelten Druckdifferenzen, infolge der Vergrösserung der Magnetkraft bei Annäherung des Ankers 85 an die Polschuhe 90, 95 eine überproportionale Zunahme des Differenzdruckes mit dem Erregerstrom ergibt.At the opening 87 of the guide membrane 74, the edge region 103 of the control region 80 can be made so soft that, in particular with large pivoting movements of the armature 85, that is to say with large regulated pressure differences, as a result of the increase in the magnetic force when the armature 85 approaches the pole shoes 90, 95 results in a disproportionate increase in the differential pressure with the excitation current.

Bei dem in Figur 5 dargestellten zweiten Ausführungsbeispiel eines Drucksteuerventiles 20' sind die gegenüber dem Ausführungsbeispiel nach Figur 3 gleichbleibenden und gleichwirkenden Teile durch die gleichen Bezugszeichen gekennzeichnet. Zwischen der unteren Gehäusehälfte 72 und der oberen Gehäusehälfte 73 ist eine Führungsmembran 74' gespannt, mit der ein topfförmig gestalteter Führungskörper 104 verbunden ist, dessen Boden aussen der Düse 76 zugewandt als Prallplatte 105 dient. Andererseits ist mit dem an der Führungsmembran 74' axial bewegbaren Führungskörper 104 ein zylinderförmig ausgestalteter Anker 106 verbunden. Die Einspannebene der Führungsmembran 74' liegt etwa in Richtung einer auf den Anker 106 wirkenden resultierenden Radialkraft. Zwischen einer ersten Stirnfläche 107 des Ankers 106 und einer Stirnfläche 108 eines Kerns 109 ist ein erster Luftspalt 110 in axialer Richtung ausgebildet, während zwischen einer abgewandten zweiten Stirnfläche 111 und einem Leitstück 112, das einerseits mit der unteren Gehäusehälfte 72 verbunden ist und andererseits über die zweite Stirnfläche 111 greift, ein zweiter axialer Luftspalt 113 ausgebildet ist. Innerhalb des Kerns 109 ist der Permanentmagnet 101 angeordnet, der mit einem Polschuh 114 derart in den Anker 106 ragt, dass beispielsweise der magnetische Fluss des Permanentmagneten 101 im ersten Luftspalt 110 dem von der Elektromagnetspule 99 erzeugten magnetischen Fluss entgegengerichtet ist, während im zweiten Luftspalt 113 der magnetische Fluss des Permanentmagneten 101 und der von der Elektromagnetspule 99 erzeugte magnetische Fluss in gleicher Richtung verlaufen. Ein sich einerseits an einem Kragen 115 der unteren Gehäusehälfte 72 und andererseits am Kern 109 abstützendes antimagnetisches Rohr 116 dient zur Abdichtung der Elektromagnetspule 99 gegenüber dem Kraftstoff. Ein Zapfen 117 am Polschuh 114, beispielsweise kegelförmig ausgebildet, kann in eine entsprechende Ausnehmung 118 des Führungskörpers 104 greifen und dient zur möglichst zentrischen Führung des Ankers 106. Die obere Gehäusehälfte 73 kann eine Schwachstelle 119 aufweisen, die bei axialer Belastung der oberen Gehäusehälfte 73 zur Einstellung des Spaltes zwischen der Prallplatte 105 und der Düse 76 axial verformt werden kann.In the second exemplary embodiment of a pressure control valve 20 ′ shown in FIG. 5, the parts that remain the same and have the same effect as in the exemplary embodiment according to FIG. 3 are identified by the same reference numerals. Between the lower housing half 72 and the upper housing half 73, a guide membrane 74 'is stretched, with which a cup-shaped guide body 104 is connected, the bottom of which, facing the nozzle 76, serves as a baffle plate 105. On the other hand, a cylinder-shaped armature 106 is connected to the guide body 104 which is axially movable on the guide membrane 74 '. The clamping plane of the guide membrane 74 'lies approximately in the direction of a resulting radial force acting on the armature 106. A first air gap 110 is formed in the axial direction between a first end face 107 of the armature 106 and an end face 108 of a core 109, while between a facing second end face 111 and a guide piece 112, which is connected on the one hand to the lower housing half 72 and on the other hand via the engages second end face 111, a second axial air gap 113 is formed. Arranged within the core 109 is the permanent magnet 101, which projects into the armature 106 with a pole piece 114 such that, for example, the magnetic flux of the permanent magnet 101 in the first air gap 110 is directed opposite the magnetic flux generated by the electromagnetic coil 99, while in the second air gap 113 the magnetic flux of the permanent magnet 101 and the magnetic flux generated by the electromagnetic coil 99 run in the same direction. An antimagnetic tube 116, which is supported on the one hand on a collar 115 of the lower housing half 72 and on the other hand on the core 109, serves to seal the electromagnetic coil 99 from the fuel. A pin 117 on the pole piece 114, for example conically shaped det, can engage in a corresponding recess 118 of the guide body 104 and is used for guiding the armature 106 as centrally as possible. The upper housing half 73 can have a weak point 119 which, when the upper housing half 73 is axially loaded, for adjusting the gap between the baffle plate 105 and the Nozzle 76 can be deformed axially.

Auch das zweite Ausführungsbeispiel nach Figur 5 bietet durch Überlagerung eines Permanentmagnetsystems mit einem Elektromagnetsystem die bereits oben zu dem Ausführungsbeispiel nach Figur 3 erwähnten Vorteile.The second exemplary embodiment according to FIG. 5 also offers the advantages already mentioned above for the exemplary embodiment according to FIG. 3 by superimposing a permanent magnet system.

Bei dem in Figur 6 dargestellten dritten Ausführungsbeispiel eines Steuerdruckventiles 20" sind die gegenüber den vorhergehenden Ausführungsbeispielen gleichbleibenden und gleichwirkenden Teile durch die gleichen Bezugszeichen gekennzeichnet. So ist in der unteren Gehäusehälfte 72 eine Führungsmembran 74" gehäusefest eingespannt, die mit einem zylinderförmigen Anker 106" in ihrem mittleren Bereich verbunden ist, der mit einem Rand 120 die Führungsmembran 74" teilweise übergreift. Der Rand 120 weist eine erste Stirnfläche 107" auf, zwischen der und einer Stirnfläche 108" des Kerns 109" ein erster Luftspalt 110" ausgebildet ist. Der ersten Stirnfläche 107" abgewandt ist am Rand 120 eine zweite Stirnfläche 111" ausgebildet, zwischen der und einem Leitstück 112" ein zweiter Luftspalt 113" ausgebildet ist, über das sich der magnetische Fluss zum unteren Gehäuse 72 hin schliessen kann. Dem Permanentmagneten 101 abgewandt ist am Anker 106" eine Prallplatte 105" ausgebildet, die mit der Düse 76 zusammenwirkt. Der Polschuh 114" des Permanentmagneten 101 ragt in den Anker 106" und ist zum Anker 106" hin sich verjüngend ausgebildet und weitgehend magnetisch gesättigt. Dadurch werden bei toleranzbedingten Exzentrizitäten die Radialkräfte reduziert und lässt sich die Ankermasse minimieren.In the third exemplary embodiment of a control pressure valve 20 ″ shown in FIG. 6, the parts that remain the same and have the same function as in the previous exemplary embodiments are identified by the same reference numerals. Thus, a guide diaphragm 74 ″ is clamped in the lower housing half 72 and is fixed with a cylindrical armature 106 ″ in is connected to its central region, which partially overlaps the guide membrane 74 ″ with an edge 120. The edge 120 has a first end face 107 ", between which and a end face 108" of the core 109 "a first air gap 110" is formed. Averted from the first end face 107 ", a second end face 111" is formed on the edge 120, between which and a guide piece 112 "a second air gap 113" is formed, via which the magnetic flux can close to the lower housing 72. A baffle plate 105 "is formed on the armature 106" facing away from the permanent magnet 101 and cooperates with the nozzle 76. The pole piece 114 "of the permanent magnet 101 projects into the armature 106" and is tapered toward the armature 106 "and largely magnetically saturated. As a result, the radial forces are reduced with tolerance-related eccentricities and the armature mass can be minimized.

Entsprechend den beiden vorhergehenden Ausführungsbeispielen verläuft beispielsweise der magnetische Fluss des Permanentmagneten 101 in dem ersten Luftspalt 110" in entgegengesetzter Richtung zum magnetischen Fluss des durch die Elektromagnetspule 99 erzeugten magnetischen Flusses, während im zweiten Luftspalt 113" beide magnetische Flüsse in gleicher Richtung verlaufen.According to the two previous exemplary embodiments, for example, the magnetic flux of the permanent magnet 101 in the first air gap 110 ″ runs in the opposite direction to the magnetic flux of the magnetic flux generated by the electromagnetic coil 99, while in the second air gap 113 ″ both magnetic fluxes run in the same direction.

Das Ausführungsbeispiel nach Figur 6 weist die Vorteile auf, wie sie bereits zu den beiden vorhergehenden Ausführungsbeispielen geschildert wurden.The exemplary embodiment according to FIG. 6 has the advantages as have already been described for the two previous exemplary embodiments.

Die Kräfte der Rückstellfeder auf den Anker einerseits und des Permanentmagneten andererseits können so aufeinander abgestimmt sein, dass die durch die Steuerdruckventile 20, 20', 20" geregelte Druckdifferenz theoretisch vom hydraulischen Durchfluss unabhängig ist.The forces of the return spring on the armature on the one hand and of the permanent magnet on the other hand can be matched to one another in such a way that the pressure difference regulated by the control pressure valves 20, 20 ', 20 "is theoretically independent of the hydraulic flow.

Claims (12)

1. Fuel injection system for mixture-compressing spark-ignited internal-combustion engines with metering valves (1) arranged in a fuel supply line (3) for metering an amount of fuel in a certain ratio to the amount of air sucked in by the internal-combustion engine, the metering taking place at constant pressure differential, which is however variable as a function of operating characteristics (33, 34, 35, 36) of the internal-combustion engine, in that the movable valve part (14) of a control valve (13) arranged downstream of each metering valve (1) and in each case controlling the pressure differential at the metering valve (1) can be impinged upon on the one hand by fuel pressure downstream of the respective metering valve (1) and on the other hand by the pressure in a control pressure line (21), which is limited on the one hand by a control pressure valve (20, 20', 20") operable as a function of operating characteristics (33, 34, 35, 36) of the internal-combustion engine and on the other hand by a control throttle (23), the control pressure valve (20, 20', 20") having a baffle plate (80, 105, 105") coupled to an armature (85, 106, 106") mounted opposite a restoring spring (74, 74', 74"), which baffle plate coacts with a control valve seat (76) which is in connection with the fuel supply line (3) and via which, when in the open state, fuel passes throttled into the control pressure line (21), wherein the armature (85, 106, 106") lies in a permanentmagnetic field (101) and an electromagnetic field (99) superimposed on the latter and electromagnetic field (99) and permanent-magnetic field (101) run partly in the same and partly in the opposite direction at the armature (85, 106, 106").
2. Fuel injection system according to Claim 1, characterised in that the disc-type armature (85) is connected to a guide membrane (74) fixed to the housing and is mounted rotatably about a torsion area (81) of the guide membrane (74) between two pole shoes (90, 91, 94, 95) in each case provided on either side of the armature (85) with air gap (92, 93, 97, 98), so that whenever the armature (85) is turned an air gap is enlarged and the other reduced on each side of the armature (85).
3. Fuel injection system according to Claim 2, characterised in that a control area (80) recessed out of the guide membrane (74) and serving as a baffle plate, is more or less rotatable with respect to the control valve seat (76) by the armature (85).
4. Fuel injection system according to Claim 3, characterised in that, facing away from the control area (80) a spring area (82) joining up with the torsion area (81) is recessed out of the guide membrane (74), at which spring area a final control element (84) engages.
5. Fuel injection system according to one of Claims 2 to 4, characterised in that in contact with in each case two pole shoes (90, 91, 94, 95) arranged on the same side of the armature (85) is a guide element (100, 102) encompassing the electromagnet coil (99) in the manner of a fork, which guide element is magnetically polarised by a permanent magnet (101).
6. Fuel injection system according to Claim 5, characterised in that the magnetic flux of electromagnet (99) and permanent magnet (101) is directed on a side of the armature (85) in each case such that in the one air gap (92, 98) between armature (85) and the one pole shoe (90, 95) the magnetic flux of electromagnet (99) and permanent magnet (101) runs in the same direction, whereas in the other air gap (93, 97) between the armature (85) and the other pole shoe (91, 94) the magnetic flux of electromagnet (99) and permanent magnet (101) is opposed.
7. Fuel injection system according to Claim 1, characterised in that the armature (106, 106") is of cylindrical design and, in axial direction between a first face (107, 107") of the armature (106, 106") and a core (109, 109") of an electromagnet coil (99), a first air gap (110) is formed and, between a second face (111, 111") and a guide piece (112, 112"), a second air gap (113, 113") is formed and a pole shoe (114, 114") of the permanent magnet (101) protrudes into the armature (106, 106") in such a way that the magnetic fluxes of electromagnet (99) and permanent magnet (101) run in one of the air gaps in the same direction and in the other air gap in opposed direction.
8. Fuel injection system according to Claim 7, characterised in that the baffle plate (105) is designed on a pot-shaped guidance element (104) connected to the armature (106) and the guidance element (104) is mounted axially displaceably on a guide membrane (74') the clamping of which to the housing takes place in a plane in which the resultant radial force acting on the armature (106) approximately runs.
9. Fuel injection system according to Claim 7, characterised in that the armature (106") is mounted axially displaceably by a guide membrane (74") firmly clamped to the housing.
10. Fuel injection system according to Claim 9, characterised in that the pole shoe (114") of the permanent magnet (101) is designed to taper towards the armature (106") and is substantially magnetically saturated.
11. Fuel injection system according to Claim 1, characterised in that, by reversal of the excitation current applied at the electromagnet (99), the control pressure valve (20, 20', 20") is opened far enough for the slight pressure differential to close the control valves (13).
12. Fuel injection system according to Claim 3 or 9, characterised in that a boundary area (103) of relatively low spring rigidity is provided between armature (85, 106") and baffle plate (80, 105").
EP19810110224 1981-03-13 1981-12-08 Fuel injection apparatus Expired EP0060344B1 (en)

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DE19813109560 DE3109560A1 (en) 1981-03-13 1981-03-13 FUEL INJECTION SYSTEM
DE3109560 1981-03-13

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EP0060344A3 EP0060344A3 (en) 1983-11-16
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Publication number Priority date Publication date Assignee Title
DE2542726A1 (en) * 1975-09-25 1977-04-07 Bosch Gmbh Robert Fuel injector for gas turbines - has equalising pressure valve in fuel return circuit controlled by counter acting springs
DE3006586A1 (en) * 1980-02-22 1981-09-03 Robert Bosch Gmbh, 7000 Stuttgart FUEL INJECTION SYSTEM

Also Published As

Publication number Publication date
JPS57163154A (en) 1982-10-07
EP0060344A3 (en) 1983-11-16
US4648368A (en) 1987-03-10
DE3109560A1 (en) 1982-09-30
EP0060344A2 (en) 1982-09-22
AU8034082A (en) 1982-09-16
JPH0312226B2 (en) 1991-02-19
AU542871B2 (en) 1985-03-21
US4545353A (en) 1985-10-08
DE3174268D1 (en) 1986-05-07

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