EP0237754A1 - Method to control a fuel injection apparatus, and fuel injection apparatus - Google Patents

Method to control a fuel injection apparatus, and fuel injection apparatus Download PDF

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Publication number
EP0237754A1
EP0237754A1 EP87101603A EP87101603A EP0237754A1 EP 0237754 A1 EP0237754 A1 EP 0237754A1 EP 87101603 A EP87101603 A EP 87101603A EP 87101603 A EP87101603 A EP 87101603A EP 0237754 A1 EP0237754 A1 EP 0237754A1
Authority
EP
European Patent Office
Prior art keywords
fuel
pressure regulator
pressure
internal combustion
combustion engine
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Withdrawn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
EP87101603A
Other languages
German (de)
French (fr)
Inventor
Siegfried Fehrenbach
Jürgen Dipl.-Ing.(FH) Gras
Dieter Dipl.-Ing.(FH) Günther
Klaus Dipl.-Ing.(FH) Joos
Ulrich Dipl.-Ing.(FH) Steinbrenner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP0237754A1 publication Critical patent/EP0237754A1/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Withdrawn legal-status Critical Current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
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/04—Introducing corrections for particular operating conditions
    • F02D41/06—Introducing corrections for particular operating conditions for engine starting or warming up
    • 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
    • F02M69/30—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel characterised by means for facilitating the starting-up or idling of engines or by means for enriching fuel charge, e.g. below operational temperatures or upon high power demand of engines
    • F02M69/36—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel characterised by means for facilitating the starting-up or idling of engines or by means for enriching fuel charge, e.g. below operational temperatures or upon high power demand of engines having an enrichment mechanism modifying fuel flow to injectors, e.g. by acting on the fuel metering device or on the valves throttling fuel passages to injection nozzles or overflow passages
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/04—Introducing corrections for particular operating conditions
    • F02D41/06—Introducing corrections for particular operating conditions for engine starting or warming up
    • F02D41/062—Introducing corrections for particular operating conditions for engine starting or warming up for starting
    • F02D41/065—Introducing corrections for particular operating conditions for engine starting or warming up for starting at hot start or restart
    • 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
    • F02M37/00—Apparatus or systems for feeding liquid fuel from storage containers to carburettors or fuel-injection apparatus; Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines
    • F02M37/20—Apparatus or systems for feeding liquid fuel from storage containers to carburettors or fuel-injection apparatus; Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines characterised by means for preventing vapour lock
    • 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
    • F02M69/30—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel characterised by means for facilitating the starting-up or idling of engines or by means for enriching fuel charge, e.g. below operational temperatures or upon high power demand of engines
    • F02M69/36—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel characterised by means for facilitating the starting-up or idling of engines or by means for enriching fuel charge, e.g. below operational temperatures or upon high power demand of engines having an enrichment mechanism modifying fuel flow to injectors, e.g. by acting on the fuel metering device or on the valves throttling fuel passages to injection nozzles or overflow passages
    • F02M69/42—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel characterised by means for facilitating the starting-up or idling of engines or by means for enriching fuel charge, e.g. below operational temperatures or upon high power demand of engines having an enrichment mechanism modifying fuel flow to injectors, e.g. by acting on the fuel metering device or on the valves throttling fuel passages to injection nozzles or overflow passages using other means than variable fluid pressure, e.g. acting on the fuel metering device mechanically or 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
    • 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
    • F02M69/54—Arrangement of fuel pressure regulators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2250/00—Engine control related to specific problems or objectives
    • F02D2250/02—Fuel evaporation in fuel rails, e.g. in common rails

Definitions

  • the invention relates to a method according to the preamble of claim 1 and a fuel injection system according to the preamble of claim 8.
  • a fuel injection system is already known in which to avoid fuel vapor bubbles after the internal combustion engine has been switched off and thus to problems during the subsequent hot start of the engine
  • Fuel pressure in the fuel injection system is increased in that the closing force of the pressure control valve is increased by an additional spring, the effect of the additional spring on the closing element of the pressure regulator being prevented by an electromagnet when the internal combustion engine is started.
  • This has the disadvantage that the electromagnet must work with great attraction and a large stroke, which has a large size, a high power loss during operation of the internal combustion engine, a large permanent load on the vehicle electrical system and control problems due to the high current required.
  • the inventive method for controlling a fuel injection system with the characterizing features of claim 1 and the fuel injection system according to the invention with the characterizing features of claim 8 have the advantage that they not only ensure a safe hot start of the internal combustion engine, but also allow that in the post-start phase after a Successful hot start for a short time, a higher fuel pressure to keep the internal combustion engine running safely or if there is an increased fuel requirement, for example when the internal combustion engine is operating at full load, a higher fuel pressure can be adjusted, which makes it possible to select a smaller injection valve size that is suitable for the lower part-load range and idling the internal combustion engine has sufficient small quantity linearity and delivers the required fuel injection quantity at full load due to the higher system pressure. Furthermore, it is advantageous that an electromagnet can be used with a significantly lower attraction force than in the prior art, which results in a lower power loss and a lower permanent load on the vehicle electrical system and a reduction in the control current.
  • Another advantageous embodiment of the invention consists in that, downstream of the first pressure regulator connected to the fuel supply line, the fuel is led to an inflow channel which ends at the valve seat of the second pressure regulator, with a valve closing member cooperating with the valve seat, which is closed by a closing spring in the direction of the valve seat can be acted upon and can be lifted off the valve seat by the pressure force of the fuel in the inflow channel or the armature of the electromagnet against the force of the closing spring.
  • the required low force of the electromagnet results in a small size and a low electrical load on the vehicle electrical system. This also enables a compact design.
  • FIG. 1 shows a first exemplary embodiment of a fuel injection system designed according to the invention
  • FIG. 2 shows a second exemplary embodiment of a fuel injection system designed according to the invention in Generaldar position
  • Figure 3 shows a third embodiment of a fuel injection system designed according to the invention in partial representation.
  • the fuel injection system shown in FIG. 1 for a mixture-compressing spark-ignition four-cylinder, four-stroke internal combustion engine 10 comprises, as essential components, four electromagnetically actuated injection valves 11, to which the fuel required for injection is supplied from a fuel supply line 12.
  • An electrically driven fuel pump 14 delivers fuel from a fuel tank 15 into a fuel connection line 16 that conducts fuel to the fuel supply line 12.
  • an outflow line 17 leads to an inlet connection 18 of a first pressure regulator 19, which regulates the fuel pressure in the fuel supply line 12 and thus regulates the fuel pressure at the injection valves 11 to a constant value of, for example, approximately 2.5 bar.
  • the construction of a pressure regulator will be described later using the pressure regulator shown in FIG. 3 as an example.
  • An outlet connection 20 of the first pressure regulator 19 is connected to a return flow line 21, via which fuel can flow back from the first pressure regulator 19 to the fuel tank 15.
  • a control valve 23 which can be actuated by an electromagnet 24.
  • the amount of fuel that can be completely combusted during the subsequent work cycle is determined by the amount of intake air entering a cylinder during a single intake stroke.
  • an air measuring element is provided in the intake pipe 25 of the internal combustion engine downstream of an air filter 26, but upstream of its throttle valve 28, which can be adjusted with an accelerator pedal 27, which is formed, for example, by a baffle plate 30, which is a function of the amount of air sucked in by the internal combustion engine performs a rotational movement against the force of a return spring (not shown), which is detected by a potentiometer (not shown) and is supplied to an electronic control unit 32 as an electrical signal of the instantaneous amount of intake air 31.
  • the electronic control unit 32 is also supplied with other values of operating parameters of the internal combustion engine converted into electrical signals, such as the temperature 33 of the intake air, the cooling water temperature 34 of the internal combustion engine, the rotational speed 35 of the internal combustion engine, the intake manifold pressure 36, and the exhaust gas composition 37 determined by an exhaust gas measuring probe in the exhaust pipe 38, the throttle valve position angle 39, contact values of a full-load switch 40 indicating the full load position of the throttle valve 28, contact values of an idle switch 41 indicating the idle position of the throttle valve 28 and others.
  • the injection valves 11 are controlled by the electronic control unit 32 as a function of operating parameters of the internal combustion engine.
  • an air line 43 branches off from the intake manifold and leads to the first pressure regulator 19 in order to influence the fuel pressure regulated by the pressure regulator as a function of the intake manifold pressure.
  • the fuel injection system has a second pressure regulator 44, which regulates a higher fuel pressure than the first pressure regulator 19, for example a fuel pressure of approximately 5 bar.
  • the second pressure regulator 44 lies in a bypass line 45, which branches off from the return flow line 21 between the first pressure regulator 19 and the control valve 23 and leads to the inlet connection 46 of the second pressure regulator 44 and via the outlet connection 47 of the second pressure regulator 44 into the return flow line 21 downstream of the control valve 23 opens.
  • the second pressure regulator 44 can also be connected to the air line 43 via a branch line 48, so that the fuel pressure regulated by the second pressure regulator 44 can also be regulated as a function of the intake manifold pressure.
  • the control valve 23 is advantageously closed when the electromagnet 24 is not energized. In normal operation of the internal combustion engine, at least outside the full-load range, the electromagnet 24 is excited by the electronic control unit 32 and opens the control valve 23, so that the fuel flows back almost without pressure via the return line 21 and the control valve 23 to the fuel tank 15 downstream of the first pressure regulator 19 can. The fuel pressure prevailing downstream of the first pressure regulator 19 is not sufficient to open the second pressure regulator 44 set to a higher pressure.
  • the fuel pressure in the fuel supply line 12 is in this operating state by the first pressure regulator 19 regulated low pressure.
  • the electromagnet 24 is de-energized and the control valve 23 closes, so that the fuel still delivered by the leaking fuel pump 14 and / or the heating of the fuel leads to an increase in pressure which is limited by the second pressure regulator 44.
  • the first pressure regulator 19 is completely open and the second pressure regulator 44 closes with respect to the return flow line 21 when the fuel pressure in the fuel supply line falls below the higher pressure to be regulated by the second pressure regulator 44, for example 5 bar. This ensures that there is no evaporation of fuel after the internal combustion engine has been switched off, where the injection valves 11 may heat up to approximately 120 ° C.
  • a fuel pressure of approximately 5 bar ensures that fuel does not evaporate in the cooling phase of the internal combustion engine, which can take up to two hours. If the internal combustion engine is restarted in the so-called hot start phase after the internal combustion engine has been switched off, the electromagnet 24 is not energized due to the values supplied to the electronic control device 32 by the operating characteristics of the internal combustion engine that characterize the hot start, so that the control valve 23 remains closed and the fuel pressure is regulated not by the first pressure regulator 19, but by the second pressure regulator 44 to approximately 5 bar.
  • the operating parameters of the internal combustion engine which characterize the hot start are either individually or in combination the values of the temperature of the cooling water 34 of the internal combustion engine, the duration of the starting process, the number of failed attempts to start, etc. These values cannot be specified for all internal combustion engines, but are different for almost every type of internal combustion engine. For example, there is a hot start at cooling water temperatures above approx. 95 ° C. The duration of the starting process should generally not exceed 2 to 3 seconds. The number of failed attempts to start should generally not exceed three.
  • the fuel pressure in a so-called post-start phase is advantageous to keep the fuel pressure in a so-called post-start phase for a short time of about 20 to 60 seconds at the higher pressure regulated by the second pressure regulator 44 in order to ensure that the internal combustion engine continues to run safely.
  • the solenoid 24 is not energized by the electronic control unit 32 and the control valve 23 thus remains closed, as a result of which the control of the fuel pressure in the fuel supply line 12 is effected by the second pressure regulator 44.
  • the duration of the post-start phase can depend on individual values or on several of the values listed below.
  • the duration of the post-start phase can vary from the temperature of the cooling water 34 of the internal combustion engine, the temperature of the air 33 in the intake manifold, for example above about 40 ° C., the total fuel throughput determined by the electronic control unit 32 through an injection valve 11, the sum of the A already done injection times, which are characterized by the excitation times of the injection valves 11, the number of injections or ignitions carried out, the sum of the intake air quantity 31 determined by means of the baffle plate 30, the instantaneous fuel throughput determined by the injection time in the electronic control unit 32 through an injection valve 11, the instantaneous through the baffle plate 30 determined intake air quantity 31, the product of the speed 35 of the internal combustion engine and a pulse serving to form the injection time, among other things.
  • the pulse used to form the injection time can be the basic pulse only taking into account the intake air quantity or a value characterizing the operating range of a factor for forming the injection time with regard to idling 41 or full load 40 and the temperature 33, 34.
  • the increase in the fuel pressure in the fuel supply line 12 and thus the regulation by the second pressure regulator 44 can also be used to satisfy an increased fuel requirement in certain operating areas of the internal combustion engine despite constant, that is to say not extended, injection times. It may be necessary to increase the fuel injection quantity at full load or acceleration.
  • the possibility of delivery of a fuel excess through Increasing the fuel pressure offers the advantage that an injection valve size can be selected which has a sufficiently large linearity linearity for idling and the lower part-load range and delivers a sufficiently large static fuel injection quantity at full load due to the increase in fuel pressure.
  • the excitation of the electromagnet 24 is interrupted by the electronic control unit 32 and the control valve 23 closes, so that the regulation of the fuel pressure in the fuel supply line 12 as described above for the hot start or the post-start phase only by the second pressure regulator 44.
  • the speed 35 and a value characterizing the air throughput 31 serve as values characterizing the increased fuel requirement at full load.
  • the electronic control unit 32 interrupts the energization of the electromagnet 24 and the control valve 23 closes, so that the fuel pressure is regulated by the second pressure regulator 44.
  • values of operating parameters can further serve to close an electrical contact in the full load position of a full load switch 40 on the throttle valve 28, the stel tion angle of the throttle valve 28, the intake air amount 31 determined by the baffle plate 30 or a corresponding pulse formed in the electronic control unit 32, the basic injection time, the intake manifold pressure and others characterize.
  • the increase in fuel pressure shown here for a hot start, in the post-start phase and when there is an increased fuel requirement, for example at full load, is also carried out by the operating parameters shown in the exemplary embodiments according to FIGS. 2 and 3 in a transferred manner.
  • the injection time in the electronic control unit 32 is adapted in accordance with the requirements of the internal combustion engine.
  • an outflow line 17 leads from the fuel supply line 12 to the inlet connection 18 of the first pressure regulator 19, which regulates, for example, a fuel pressure of approximately 2.5 bar.
  • the outlet port 20 of the first pressure regulator 19 is connected to the return flow line 21, in which the control valve 23 is located, which can be actuated by the electromagnet 24 which can be excited by the electronic control device 32 in the manner described above as a function of operating parameters of the internal combustion engine.
  • the inlet connection 46 of the second pressure regulator 44 is connected to the fuel supply line 12 via an outflow line 50.
  • the outlet 47 of the second pressure regulator 44 leads via a return line 51 to the return flow line 21 downstream of the control valve 23, so that the second pressure regulator 44, which regulates a fuel pressure of 5 bar, is parallel to the first pressure regulator 19.
  • the control valve 23 is closed when the electromagnet 24 is not energized, for example during the hot start, the post-start phase and operating parameters which characterize an increased fuel requirement, so that the second pressure regulator 44 then takes effect and regulates a fuel pressure of approximately 5 bar in the fuel supply line 12.
  • the electromagnet 24 is likewise de-energized and the control valve 23 closes, so that a fuel pressure which completely or at least substantially reduces the formation of vapor bubbles builds up in the fuel injection system and a new hot start is made possible.
  • the third exemplary embodiment according to FIG. 3 shows in a compact construction a second pressure regulator 44 which is directly connected to the first pressure regulator 19.
  • the first pressure regulator 19 regulates, for example, a fuel pressure in the fuel supply line of approximately 2.5 bar, while the second pressure regulator 44 regulates a higher fuel pressure of approximately Regulates 5 bar.
  • the first pressure regulator 19 is constructed from a valve housing 53 and a valve cap 54, the inlet connector 18 being arranged on the valve housing.
  • valve housing 53 and valve cap 54 can be formed as sheet metal deep-drawn parts which are connected by a flange 60, whereby a membrane 62 is also clamped transversely to the longitudinal axis of the pressure regulator 19.
  • a bracket 64 is fastened to the diaphragm 62 together with a spring plate 63, in which a valve closing member 65 is pivotally mounted, which has a closure disk 66 and a ball 67 rigidly connected (soldered) to it.
  • the ball 67 is guided through a retaining washer 68 in a conical bore 69 of the holder 64 and is pressed against the retaining washer 68 by a spring 71 arranged in a bore 70 of the holder 64, so that the locking washer 66 is prevented from being hit by vibrations.
  • the closure disk 66 forms, together with the fixed valve seat 59, the flow cross section of the pressure regulator.
  • the membrane 62 separates the fuel chamber 57 from a spring chamber 73 in the valve cap 54.
  • a valve spring 74 is arranged in the spring chamber 73, one end of which rests on the spring plate 63 and acts on the valve closing member 65 in the direction of the fixed valve seat 59.
  • the air line 43 advantageously opens into the spring chamber 73.
  • an outlet opening 79 leads through the valve seat body 58 and is connected to an inflow channel 80 which is in the outlet connection 20 of the first pressure regulator 19 is formed and ends at a valve seat 82.
  • the fastening end 75 of the outlet connector 20 of the first pressure regulator 19 has a blind bore 83, from the bottom of which the valve seat 82 protrudes.
  • a cylindrical armature 84 projects into the blind bore 83 and has a smaller diameter than the blind bore 83 and limits an annular space with the latter.
  • the armature 84 is aligned with the valve seat 82 and, on its end face 85 facing the valve seat 82, is connected to a valve closing element 86 which interacts with the valve seat 82.
  • a closing spring 88 is supported, which on the other hand rests on the outlet connection 47.
  • the armature 84 is slidably mounted within the pot housing 77 in a sliding bush 89 which is mounted in a magnet coil 90 arranged inside the pot housing 77.
  • the armature 84 has at its end 85 facing the valve closing member 86 a transverse bore 92 which is connected to a longitudinal bore 93 in the armature.
  • the longitudinal bore 93 ends at the end 87 of the armature 84.
  • a set screw 94 can be screwed into the connecting piece 47, on which the end of the closing spring 88 which is remote from the armature 84 is supported.
  • the tension force of the closing spring 88 and thus the opening force required to open the second pressure regulator 44 can be set, by which the fuel pressure regulated by the second pressure regulator 44 is determined.
  • the outlet 95 of the outlet port 47 communicates with the return flow line 21.
  • the electronic control unit 32 excites the electromagnet 24, characterized by the solenoid 90, and the armature 84 and thus the valve closing member 86 are lifted from the valve seat 82 against the force of the closing spring 88, so that the fuel flowing from the fuel supply line 12 via the inlet connection 18 to the first pressure regulator 19 is regulated by the first pressure regulator 19 to a pressure of approximately 2.5 bar and via the outlet connection 20 as a result of the open between pressure regulator 44 to the outlet connection 47 of the second pressure regulator 44 can flow.
  • the electronic control unit 32 does not excite the electromagnet 24 in the manner described above, so that the second pressure regulator 44 only opens, i.e. the valve closing member 86 from the valve seat 82 lifts off when the fuel pressure in the inflow channel 80 and thus also in the fuel supply line 12 reaches at least the opening pressure of the second pressure regulator, that is to say about 5 bar.
  • a stop 96 is arranged in the spring chamber 73, on which the holder 64 can be supported when the fuel pressure is regulated by the second pressure regulator 44.

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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)
  • Fluid Mechanics (AREA)
  • Fuel-Injection Apparatus (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Abstract

A method of controlling a fuel injection system and a fuel injection system are proposed for supplying fuel to an internal combustion engine with mixture compression and applied ignition. The fuel injection system comprises at least one injection valve (11) injecting fuel into the intake pipe (25) of the internal combustion engine, a fuel supply line (12) and a pressure regulating device connected to the fuel supply line (12), which device comprises a first pressure regulator (19), a second pressure regulator (44) and a control valve (23) with a solenoid (24). The inlet pipe (18) of the first pressure regulator (19) is connected to the fuel supply line (12) whilst the outlet pipe (20) lies on a return line (21) on which the control valve (23) is located. The second pressure regulator (44), which sets a higher fuel pressure than the first pressure regulator (19), is located on a bypass line (45) to the control valve (23). In the non-energised state the control valve (23) is closed so that when the internal combustion engine is running the fuel pressure is regulated by means of the second pressure regulator (44), which leads to a higher fuel pressure. The solenoid (24) is de-energised by the electronic control unit (32) not only when the internal combustion engine is shut off but also in the event of operating variables characteristic of hot starting of the internal combustion engine, in the re-start phase following a hot start and in the event of operating states characteristic of an increased fuel requirement, for example at full load. <IMAGE>

Description

Stand der TechnikState of the art

Die Erfindung geht aus von einem Verfahren nach der Gat­tung des Anspruches 1 und einer Kraftstoffeinspritzanlage nach der Gattung des Anspruches 8. Es ist schon eine der­artige Kraftstoffeinspritzanlage bekannt, bei der zur Ver­meidung von Kraftstoffdampfblasen nach dem Abstellen der Brennkraftmaschine und damit von Problemen beim nachfol­genden Heißstart der Kraftstoffdruck in der Kraftstoff­einspritzanlage dadurch erhöht wird, daß die Schließkraft des Druckregelventiles durch eine Zusatzfeder erhöht wird, wobei die Wirkung der Zusatzfeder auf das Schließ­glied des Druckreglers beim Starten der Brennkraftmaschine durch einen Elektromagneten unterbunden wird. Dabei ergibt sich der Nachteil, daß der Elektromagnet mit großer Anziehungskraft und großem Hub arbeiten muß, was eine große Baugröße, eine hohe Verlustleistung während des Betriebes der Brennkraftmaschine, eine große Dauerbelastung des Bordnetzes des Kraftfahr­zeuges und Ansteuerprobleme wegen des erforderlichen hohen Stromes zur Folge hat.The invention relates to a method according to the preamble of claim 1 and a fuel injection system according to the preamble of claim 8. Such a fuel injection system is already known in which to avoid fuel vapor bubbles after the internal combustion engine has been switched off and thus to problems during the subsequent hot start of the engine Fuel pressure in the fuel injection system is increased in that the closing force of the pressure control valve is increased by an additional spring, the effect of the additional spring on the closing element of the pressure regulator being prevented by an electromagnet when the internal combustion engine is started. This has the disadvantage that the electromagnet must work with great attraction and a large stroke, which has a large size, a high power loss during operation of the internal combustion engine, a large permanent load on the vehicle electrical system and control problems due to the high current required.

Vorteile der ErfindungAdvantages of the invention

Das erfindungsgemäße Verfahren zum Steuern einer Kraft­stoffeinspritzanlage mit den kennzeichnenden Merkmalen des Anspruches 1 und die erfindungsgemäße Kraftstoffein­spritzanlage mit dem kennzeichnenden Merkmalen des An­spruches 8 haben den Vorteil, daß sie nicht nur einen sicheren Heißstart der Brennkraftmaschine gewährleisten, sondern auch ermöglichen, daß in der Nachstartphase nach einem erfolgreichen Heißstart noch kurze Zeit ein höherer Kraftstoffdruck zum sicheren Weiterlaufen der Brennkraftmaschine oder beim Vorliegen von erhöhtem Kraftstoffbedarf, beispielsweise bei Vollastbetrieb der Brennkraftmaschine, ein höherer Kraftstoffdruck einregelbar ist, wodurch die Möglichkeit besteht, eine kleinere Einspritzventilgröße zu wählen, die für den unteren Teillastbereich und Leerlauf der Brennkraft­maschine eine ausreichende Kleinmengenlinearität auf­weist und bei Vollast durch den höheren Systemdruck die benötigte Kraftstoffeinspritzmenge liefert. Weiter­hin ist es vorteilhaft, daß mit einem Elektromagneten mit wesentlich geringerer Anziehungskraft als beim Stand der Technik gearbeitet werden kann, wodurch sich eine geringere Verlustleistung und eine geringere Dauer­belastung des Bordnetzes des Kraftfahrzeuges sowie eine Verringerung des Ansteuerstromes ergibt.The inventive method for controlling a fuel injection system with the characterizing features of claim 1 and the fuel injection system according to the invention with the characterizing features of claim 8 have the advantage that they not only ensure a safe hot start of the internal combustion engine, but also allow that in the post-start phase after a Successful hot start for a short time, a higher fuel pressure to keep the internal combustion engine running safely or if there is an increased fuel requirement, for example when the internal combustion engine is operating at full load, a higher fuel pressure can be adjusted, which makes it possible to select a smaller injection valve size that is suitable for the lower part-load range and idling the internal combustion engine has sufficient small quantity linearity and delivers the required fuel injection quantity at full load due to the higher system pressure. Furthermore, it is advantageous that an electromagnet can be used with a significantly lower attraction force than in the prior art, which results in a lower power loss and a lower permanent load on the vehicle electrical system and a reduction in the control current.

Durch die in den Unteransprüchen aufgeführten Maßnahmen sind vorteilhaft Weiterbildungen und Verbesserungen des Verfahrens nach Anspruch 1 und der Kraftstoffeinspritz­anlage nach Anspruch 8 möglich.The measures listed in the subclaims advantageously further developments and improvements of the method according to claim 1 and the fuel injection system according to claim 8 are possible.

Besonders vorteilhaft ist es, die Regelung des Kraft­stoffdruckes in der Kraftstoffversorgungsleitung durch den zweiten Druckregler nur beim Vorliegen von den Heißstart der Brennkraftmaschine, die Nachstartphase nach einem Heißstart oder bei Vorliegen den Bedarf einer erhöhten Kraftstoffmenge kennzeichnenden Betriebs­kenngrößen der Brennkraftmaschine vorzunehmen.It is particularly advantageous to regulate the fuel pressure in the fuel supply line by means of the second pressure regulator only when the internal combustion engine is hot started, the post-start phase after a hot start or when there is an operating quantity of the internal combustion engine characterizing the need for an increased fuel quantity.

Eine ebenfalls vorteilhafte Ausgestaltung der Erfindung besteht darin, daß stromabwärts des mit der Kraftstoff­versorgungsleitung verbundenen ersten Druckreglers der Kraftstoff zu einem Zuströmkanal geführt wird, der am Ventilsitz des zweiten Druckreglers endet, wobei mit dem Ventilsitz ein Ventilschließglied zusammenwirkt, das durch eine Schließfeder in Richtung zum Ventilsitz hin beaufschlagbar und durch die Druckkraft des Kraftstof­fesim Zuströmkanal oder den Anker des Elektromagneten entgegen der Kraft der Schließfeder vom Ventilsitz abhebbar ist. Durch die erforderliche geringe Kraft des Elektromagneten ergibt sich eine geringe Baugröße und eine geringe elektrische Belastung des Bordnetzes des Kraftfahrzeuges. Weiterhin ist hierdurch eine kom­pakte Bauweise möglich.Another advantageous embodiment of the invention consists in that, downstream of the first pressure regulator connected to the fuel supply line, the fuel is led to an inflow channel which ends at the valve seat of the second pressure regulator, with a valve closing member cooperating with the valve seat, which is closed by a closing spring in the direction of the valve seat can be acted upon and can be lifted off the valve seat by the pressure force of the fuel in the inflow channel or the armature of the electromagnet against the force of the closing spring. The required low force of the electromagnet results in a small size and a low electrical load on the vehicle electrical system. This also enables a compact design.

Zeichnungdrawing

Ausführungsbeispiele der Erfindung sind in der Zeich­nung vereinfacht dargestellt und in der nachfolgenden Beschreibung näher erläutert. Es zeigen Figur 1 ein erstes Ausführungsbeispiel einer erfindungsgemäß aus­gestalteten Kraftstoffeinspritzanlage, Figur 2 ein zweites Ausführungsbeispiel einer erfindungsgemäß aus­gestalteten Kraftstoffeinspritzanlage in Teildar­ stellung, Figur 3 ein drittes Ausführungsbeispiel einer erfindungsgemäß ausgestalteten Kraftstoffeinspritzanlage in Teildarstellung.Embodiments of the invention are shown in simplified form in the drawing and explained in more detail in the following description. FIG. 1 shows a first exemplary embodiment of a fuel injection system designed according to the invention, FIG. 2 shows a second exemplary embodiment of a fuel injection system designed according to the invention in Teildar position, Figure 3 shows a third embodiment of a fuel injection system designed according to the invention in partial representation.

Beschreibung der AusführungsbeispieleDescription of the embodiments

Die in der Figur 1 dargestellte Kraftstoffeinspritzanlage für eine gemischverdichtende fremdgezündete Vierzylinder-­Viertakt-Brennkraftmaschine 10 umfaßt als wesentliche Be­standteile vier elektromagnetisch betätigbare Einspritz­ventile 11, denen aus einer Kraftstoffversorgungsleitung 12 der zur Einspritzung erforderliche Kraftstoff zugeführt wird. Eine elektrisch angetriebene Kraftstoffpumpe 14 fördert aus einem Kraftstoffbehälter 15 Kraftstoff in eine Kraftstoff zur Kraftstoffversorgungsleitung 12 lei­tenden Kraftstoffverbindungsleitung 16. Insbesondere vom abströmseitigen Ende der Kraftstoffversorgungsleitung 12 führt eine Abströmleitung 17 zu einem Einlaßstutzen 18 eines ersten Druckreglers 19, der den Kraftstoffdruck in der Kraftstoffversorgungsleitung 12 und damit den an den Einspritzventilen 11 anstehenden Kraftstoffdruck auf einen konstanten Wert von beispielsweise ca. 2,5 bar regelt. Der konstruktive Aufbau eines Druckreglers wird später beispielhaft an dem in Figur 3 dargestell­ten Druckregler beschrieben. Ein Auslaßstutzen 20 des ersten Druckreglers 19 ist mit einer Rückström­leitung 21 verbunden, über die Kraftstoff von dem ersten Druckregler 19 zum Kraftstoffbehälter 15 rück­strömen kann. In der Rückströmleitung 21 liegt ein Steuerventil 23, das durch einen Elektromagneten 24 betätigbar ist.The fuel injection system shown in FIG. 1 for a mixture-compressing spark-ignition four-cylinder, four-stroke internal combustion engine 10 comprises, as essential components, four electromagnetically actuated injection valves 11, to which the fuel required for injection is supplied from a fuel supply line 12. An electrically driven fuel pump 14 delivers fuel from a fuel tank 15 into a fuel connection line 16 that conducts fuel to the fuel supply line 12. In particular, from the outflow end of the fuel supply line 12, an outflow line 17 leads to an inlet connection 18 of a first pressure regulator 19, which regulates the fuel pressure in the fuel supply line 12 and thus regulates the fuel pressure at the injection valves 11 to a constant value of, for example, approximately 2.5 bar. The construction of a pressure regulator will be described later using the pressure regulator shown in FIG. 3 as an example. An outlet connection 20 of the first pressure regulator 19 is connected to a return flow line 21, via which fuel can flow back from the first pressure regulator 19 to the fuel tank 15. In the return flow line 21 there is a control valve 23 which can be actuated by an electromagnet 24.

Bei gemischverdichtenden, mit Fremdzündung arbeitenden Brennkraftmaschinen der dargestellten Art wird durch die bei einem einzelnen Ansaughub in einen Zylinder gelan­gende Ansaugluftmenge diejenige Kraftstoffmenge festge­legt, die während des nachfolgenden Arbeitstaktes voll­ständig verbrannt werden kann. Um das gewünschte stöchio­metrische Verhältnis zwischen Ansaugluft und Kraftstoff zu erzielen, ist im Ansaugrohr 25 der Brennkraftmaschine stromabwärts eines Luftfilters 26, jedoch stromaufwärts ihrer mit einem Gaspedal 27 verstellbaren Drosselklappe 28 ein Luftmeßorgan vorgesehen, das beispielsweise durch eine Stauscheibe 30 gebildet wird, die in Abhängigkeit von der durch die Brennkraftmaschine angesaugten Luft­menge entgegen der Kraft einer nicht dargestellten Rückstellfeder eine Drehbewegung ausführt, die durch ein nicht dargestelltes Potentiometer erfaßt und als elektri­sches Signal der momentanen Ansaugluftmenge 31 einem elektronischen Steuergerät 32 zugeleitet wird. Dem elek­tronischen Steuergerät 32 werden weiterhin noch andere Werte von in elektrische Signale umgewandelten Betriebs­kenngrößen der Brennkraftmaschine zugeleitet wie die Temperatur 33 der Ansaugluft, die Kühlwassertemperatur 34 der Brennkraftmaschine, die Drehzahl 35 der Brenn­kraftmaschine, der Saugrohrdruck 36, die Abgaszusammen­setzung 37 ermittelt durch eine Abgasmeßsonde im Abgas­rohr 38, den Drosselklappenstellungswinkel 39, Kontakt­werte eines die Vollaststellung der Drosselklappe 28 an­zeigenden Vollastschalter 40, Kontaktwerte eines die Leerlaufstellung der Drosselklappe 28 anzeigenden Leer­laufschalters 41 und andere. Die Ansteuerung der Ein­spritzventile 11 in Abhängigkeit von Betriebskenngrößen der Brennkraftmaschine erfolgt durch das elektronische Steuergerät 32.In the case of mixture-compressing internal combustion engines of the type shown, which are operated with spark ignition, the amount of fuel that can be completely combusted during the subsequent work cycle is determined by the amount of intake air entering a cylinder during a single intake stroke. In order to achieve the desired stoichiometric ratio between intake air and fuel, an air measuring element is provided in the intake pipe 25 of the internal combustion engine downstream of an air filter 26, but upstream of its throttle valve 28, which can be adjusted with an accelerator pedal 27, which is formed, for example, by a baffle plate 30, which is a function of the amount of air sucked in by the internal combustion engine performs a rotational movement against the force of a return spring (not shown), which is detected by a potentiometer (not shown) and is supplied to an electronic control unit 32 as an electrical signal of the instantaneous amount of intake air 31. The electronic control unit 32 is also supplied with other values of operating parameters of the internal combustion engine converted into electrical signals, such as the temperature 33 of the intake air, the cooling water temperature 34 of the internal combustion engine, the rotational speed 35 of the internal combustion engine, the intake manifold pressure 36, and the exhaust gas composition 37 determined by an exhaust gas measuring probe in the exhaust pipe 38, the throttle valve position angle 39, contact values of a full-load switch 40 indicating the full load position of the throttle valve 28, contact values of an idle switch 41 indicating the idle position of the throttle valve 28 and others. The injection valves 11 are controlled by the electronic control unit 32 as a function of operating parameters of the internal combustion engine.

Stromabwärts der Drosselklappe 28 zweigt vom Saugrohr eine Luftleitung 43 ab, die zu dem ersten Druckregler 19 führt, um den durch den Druckregler geregelten Kraft­stoffdruck in Abhängigkeit vom Saugrohrdruck zu beein­flussen. Gemäß dem Ausführungsbeispiel der Erfindung nach Figur 1 weist die Kraftstoffeinspritzanlage einen zweiten Druckregler 44 auf, der einen höheren Kraft­stoffdruck als der erste Druckregler 19 regelt, bei­spielsweise einen Kraftstoffdruck von etwa 5 bar. Der zweite Druckregler 44 liegt in einer Bypaßleitung 45, die von der Rückströmleitung 21 zwischen dem ersten Druckregler 19 und dem Steuerventil 23 abzweigt und zum Einlaßstutzen 46 des zweiten Druckreglers 44 führt und über den Auslaßstutzen 47 des zweiten Druckreglers 44 in die Rückströmleitung 21 stromabwärts des Steuerven­tils 23 mündet. Der zweite Druckregler 44 kann über eine Stichleitung 48 ebenfalls mit der Luftleitung 43 in Ver­bindung stehen, so daß der durch den zweiten Druckregler 44 geregelten Kraftstoffdruck ebenfalls saugrohrdruck­abhängig geregelt werden kann. Vorteilhafterweise ist das Steuerventil 23 bei nichterregtem Elektromagneten 24 geschlossen. Im normalen Betrieb der Brennkraftmaschine, zumindest außerhalb des Vollastbereiches, wird der Elek­tromagnet 24 durch das elektronische Steuergerät 32 er­regt und öffnet das Steuerventil 23, so daß stromabwärts des ersten Druckreglers 19 der Kraftstoff nahezu drucklos über die Rückströmleitung 21 und das Steuerventil 23 zum Kraftstoffbehälter 15 zurückströmen kann. Der strom­abwärts des ersten Druckreglers 19 herrschende Kraft­stoffdruck reicht dabei nicht aus, um den auf einen höheren Druck eingestellten zweiten Druckregler 44 zu öffnen. Der Kraftstoffdruck in der Kraftstoffversorgungs­leitung 12 wird in diesem Betriebszustand durch den ersten Druckregler 19 niederen Druckes geregelt. Beim Abstellen der Brennkraftmaschine wird der Elektromagnet 24 stromlos und das Steuerventil 23 schließt, so daß der von der auslaufenden Kraftstoffpumpe 14 noch geför­derte Kraftstoff und/oder die Erwärmung des Kraftstoffes zu einer Drucksteigerung führt, die durch den zweiten Druckregler 44 begrenzt wird. Dabei ist der erste Druck­regler19 ganz geöffnet und der zweite Druckregler 44 schließt gegenüber der Rückströmleitung 21, wenn der Kraftstoffdruck in der Kraftstoffversorgungsleitung den von dem zweiten Druckregler 44 zu regelnden höheren Druck von beispielsweise 5 bar unterschreitet. Hierdurch wird erreicht, daß es nach dem Abstellen der Brennkraftmaschine, wo es unter Umständen zu einer Aufheizung der Einspritz­ventile 11 auf ca. 120° C durch die nicht mehr gekühlte Brennkraftmaschine kommen kann, zu keinem Ausdampfen von Kraftstoff kommt, was zumindest in einer sogenannten Heiß­startphase bei einem erneuten Starten der Brennkraftma­schine zu Startschwierigkeiten oder zu einem Stehenbleiben der Brennkraftmaschine führen würde. Ein Kraftstoff­druck von etwa 5 bar gewährleistet, daß in der Abkühl­phase der Brennkraftmaschine, die bis zu zwei Stunden dauern kann, Kraftstoff nicht ausdampft. Wird nach dem Abstellen der Brennkraftmaschine in der sogenannten Heißstartphase die Brennkraftmaschine erneut gestartet, so erfolgt aufgrund der dem elektronischen Steuergerät 32 zugeleiteten Werte von den Heißstart kennzeichnenden Betriebskenngrößen der Brennkraftmaschine keine Erregung des Elektromagneten 24, so daß das Steuerventil 23 geschlossen bleibt und die Regelung des Kraftstoffdruckes nicht durch den ersten Druckregler 19, sondern durch den zweiten Druckregler 44 auf ca. 5 bar erfolgt. Dadurch wird die Dampfblasenbildung auch am Zumeßspalt der Ein­ spritzventile verhindert oder zumindest auf eine unschäd­liche Menge während des Startvorganges reduziert. Den Heißstart kennzeichnende Betriebskenngrößen der Brenn­kraftmaschine sind entweder einzeln oder in Kombination die Werte der Temperatur des Kühlwassers 34 der Brenn­kraftmaschine, der zeitlichen Dauer des Startvorganges, die Anzahl der Startfehlversuche u.a.. Diese Werte können nicht allgemeingültig für alle Brennkraftmaschinen ange­geben werden, sondern sind für fast jeden Brennkraft­maschinentyp anders. Beispielsweise liegt ein Heißstart bei Kühlwassertemperaturen oberhalb ca. 95° C vor. Die Dauer des Startvorganges sollte in der Regel 2 bis 3 Sekunden nicht überschreiten. Die Anzahl der Start-­Fehlversuche sollte in der Regel nicht über drei liegen. Nach einem erfolgreichen Heißstart ist es vorteilhaft, den Kraftstoffdruck in einer sogenannten Nachstartphase noch eine kurze Zeit von ca. 20 bis 60 Sekunden auf dem durch den zweiten Druckregler 44 geregelten höheren Druck zu halten, um einen sicheren Weiterlauf der Brenn­kraftmaschine zu gewährleisten. Das bedeutet, daß auch in der Nachstartphase keine Erregung des Elektromagneten 24 durch das elektronische Steuergerät 32 erfolgt und damit das Steuerventil 23 geschlossen bleibt, wodurch die Regelung des Kraftstoffdruckes in der Kraftstoffversor­gungsleitung 12 durch den zweiten Druckregler 44 bewirkt wird. Die Dauer der Nachstartphase kann dabei von einzel­nen Werten oder von mehreren der nachfolgend aufgeführten Werte abhängen. Die Dauer der Nachstartphase kann von der Temperatur des Kühlwassers 34 der Brennkraftmaschine, der Temperatur der Luft 33 im Saugrohr, beispielsweise über ca. 40° C, der durch das elektronische Steuergerät 32 ermittelten gesamten Kraftstoffdurchsatzmenge durch ein Einspritzventil 11, die Summe der bereits erfolgten Ein­ spritzzeiten, die durch die Erregungszeiten der Einspritz­ventile 11 gekennzeichnet sind, die Anzahl der erfolgten Einspritzungen oder Zündungen, die Summe der mittels der Stauscheibe 30 ermittelten Ansaugluftmenge 31, den anhand der Einspritzzeit im elektronischen Steuergerät 32 ermit­telten momentanen Kraftstoffdurchsatz durch ein Einspritz­ventil 11, die momentane durch die Stauscheibe 30 ermit­telte Ansaugluftmenge 31, das Produkt aus der Drehzahl 35 der Brennkraftmaschine und einem zur Bildung der Einspritz­zeit dienenden Impuls u.a. abhängen. Dabei kann als zur Bildung der Einspritzzeit dienender Impuls der nur die Ansaugluftmenge berücksichtigende Grundimpuls dienen oder ein den Betriebsbereich kennzeichnender Wert eines Faktors zur Bildung der Einspritzzeit bezüglich Leerlauf 41 oder Vollast 40 sowie der Temperatur 33, 34. Nach dem Abschluß der Nachstartphase wird der Elektromagnet 24 durch das elektronische Steuergerät 32 erregt und öffnet das Steuer­ventil 23, wodurch der Kraftstoffdruck stromabwärts des ersten Druckreglers 19 auf nahezu Atmosphärendruck absinkt und der zweite Druckregler 44 schließt, so daß die Druck­regelung des Kraftstoffes in der Kraftstoffversorgungs­leitung nun auf einem niederen Druck von ca. 2,5 bar durch den ersten Druckregler 19 erfolgt.Downstream of the throttle valve 28, an air line 43 branches off from the intake manifold and leads to the first pressure regulator 19 in order to influence the fuel pressure regulated by the pressure regulator as a function of the intake manifold pressure. According to the exemplary embodiment of the invention according to FIG. 1, the fuel injection system has a second pressure regulator 44, which regulates a higher fuel pressure than the first pressure regulator 19, for example a fuel pressure of approximately 5 bar. The second pressure regulator 44 lies in a bypass line 45, which branches off from the return flow line 21 between the first pressure regulator 19 and the control valve 23 and leads to the inlet connection 46 of the second pressure regulator 44 and via the outlet connection 47 of the second pressure regulator 44 into the return flow line 21 downstream of the control valve 23 opens. The second pressure regulator 44 can also be connected to the air line 43 via a branch line 48, so that the fuel pressure regulated by the second pressure regulator 44 can also be regulated as a function of the intake manifold pressure. The control valve 23 is advantageously closed when the electromagnet 24 is not energized. In normal operation of the internal combustion engine, at least outside the full-load range, the electromagnet 24 is excited by the electronic control unit 32 and opens the control valve 23, so that the fuel flows back almost without pressure via the return line 21 and the control valve 23 to the fuel tank 15 downstream of the first pressure regulator 19 can. The fuel pressure prevailing downstream of the first pressure regulator 19 is not sufficient to open the second pressure regulator 44 set to a higher pressure. The fuel pressure in the fuel supply line 12 is in this operating state by the first pressure regulator 19 regulated low pressure. When the internal combustion engine is switched off, the electromagnet 24 is de-energized and the control valve 23 closes, so that the fuel still delivered by the leaking fuel pump 14 and / or the heating of the fuel leads to an increase in pressure which is limited by the second pressure regulator 44. The first pressure regulator 19 is completely open and the second pressure regulator 44 closes with respect to the return flow line 21 when the fuel pressure in the fuel supply line falls below the higher pressure to be regulated by the second pressure regulator 44, for example 5 bar. This ensures that there is no evaporation of fuel after the internal combustion engine has been switched off, where the injection valves 11 may heat up to approximately 120 ° C. under certain circumstances, which occurs at least in a so-called hot start phase when starting the internal combustion engine again would lead to starting difficulties or to a standstill of the internal combustion engine. A fuel pressure of approximately 5 bar ensures that fuel does not evaporate in the cooling phase of the internal combustion engine, which can take up to two hours. If the internal combustion engine is restarted in the so-called hot start phase after the internal combustion engine has been switched off, the electromagnet 24 is not energized due to the values supplied to the electronic control device 32 by the operating characteristics of the internal combustion engine that characterize the hot start, so that the control valve 23 remains closed and the fuel pressure is regulated not by the first pressure regulator 19, but by the second pressure regulator 44 to approximately 5 bar. As a result, the formation of vapor bubbles is also at the metering gap spray valves prevented or at least reduced to a harmless amount during the starting process. The operating parameters of the internal combustion engine which characterize the hot start are either individually or in combination the values of the temperature of the cooling water 34 of the internal combustion engine, the duration of the starting process, the number of failed attempts to start, etc. These values cannot be specified for all internal combustion engines, but are different for almost every type of internal combustion engine. For example, there is a hot start at cooling water temperatures above approx. 95 ° C. The duration of the starting process should generally not exceed 2 to 3 seconds. The number of failed attempts to start should generally not exceed three. After a successful hot start, it is advantageous to keep the fuel pressure in a so-called post-start phase for a short time of about 20 to 60 seconds at the higher pressure regulated by the second pressure regulator 44 in order to ensure that the internal combustion engine continues to run safely. This means that, even in the post-start phase, the solenoid 24 is not energized by the electronic control unit 32 and the control valve 23 thus remains closed, as a result of which the control of the fuel pressure in the fuel supply line 12 is effected by the second pressure regulator 44. The duration of the post-start phase can depend on individual values or on several of the values listed below. The duration of the post-start phase can vary from the temperature of the cooling water 34 of the internal combustion engine, the temperature of the air 33 in the intake manifold, for example above about 40 ° C., the total fuel throughput determined by the electronic control unit 32 through an injection valve 11, the sum of the A already done injection times, which are characterized by the excitation times of the injection valves 11, the number of injections or ignitions carried out, the sum of the intake air quantity 31 determined by means of the baffle plate 30, the instantaneous fuel throughput determined by the injection time in the electronic control unit 32 through an injection valve 11, the instantaneous through the baffle plate 30 determined intake air quantity 31, the product of the speed 35 of the internal combustion engine and a pulse serving to form the injection time, among other things. The pulse used to form the injection time can be the basic pulse only taking into account the intake air quantity or a value characterizing the operating range of a factor for forming the injection time with regard to idling 41 or full load 40 and the temperature 33, 34. After the end of the post-start phase, the electromagnet 24 excited and opened by the electronic control unit 32, the control valve 23, whereby the fuel pressure downstream of the first pressure regulator 19 drops to almost atmospheric pressure and the second pressure regulator 44 closes, so that the pressure control of the fuel in the fuel supply line is now at a low pressure of approx. 5 bar by the first pressure regulator 19.

Die Erhöhung des Kraftstoffdruckes in der Kraftstoff­versorgungsleitung 12 und damit die Regelung durch den zweiten Druckregler 44 kann auch noch dazu verwendet wer­den, einen erhöhten Kraftstoffbedarf in bestimmten Betriebs­bereichen der Brennkraftmaschine trotz gleichbleibender, also nicht verlängerter Einspritzzeiten zu befriedigen. So kann es erforderlich sein, bei Vollast oder Beschleu­nigung die Kraftstoffeinspritzmenge zu erhöhen. Die Mög­lichkeit der Lieferung einer Kraftstoffmehrmenge durch Erhöhung des Kraftstoffdruckes bietet den Vorteil, daß eine Einspritzventilgröße gewählt werden kann, die für Leer­lauf und den unteren Teillastbereich eine genügend große Kleinmengenlinearität aufweist und bei Vollast durch die Kraftstoffdruckerhöhung eine ausreichend große statische Kraftstoffeinspritzmenge liefert. Werden be­stimmte, den erhöhten Kraftstoffbedarf kennzeichnende Werte der Betriebskenngrößen erreicht, so wird die Erre­gung des Elektromagneten 24 durch das elektronische Steuergerät 32 unterbrochen und das Steuerventil 23 schließt, so daß die Regelung des Kraftstoffdruckes in der Kraftstoffversorgungsleitung 12 wie bereits oben zum Heißstart oder zur Nachstartphase beschrieben nur durch den zweiten Druckregler 44 erfolgt. Als den erhöh­ten Kraftstoffbedarf bei Vollast kennzeichnende Werte dienen die Drehzahl 35 sowie ein den Luftdurchsatz 31 kennzeichnender Wert. Sobald diese Werte einen Schwellen­wert überschreiten, unterbricht das elektronische Steuer­gerät 32 die Erregung des Elektromagneten 24 und das Steuerventil 23 schließt, so daß die Kraftstoffdruck­regelung durch den zweiten Druckregler 44 erfolgt. Werden danach diese Schwellenwerte wieder in umgekehrter Rich­tung überquert, so wird der Elektromagnet 24 durch das elektronische Steuergerät 32 erregt und das Steuer­ventil 23 öffnet, so daß die Druckregelung des Kraft­stoffes nun wieder durch den ersten Druckregler 19 auf dem niedereren Niveau erfolgt. Zur Kennzeichnung des erhöhten Kraftstoffbedarfes bei Vollast mit der Folge einer Entregung des Elektromagneten 24 und zur Bestimmung der Dauer des erhöhten Kraftstoffdruckes können weiterhin Werte von Betriebskenngrößen dienen, die das Schließen eines elektrischen Kontaktes in Vollaststellung eines Vollastschalters 40 an der Drosselklappe 28, den Stel­ lungswinkel der Drosselklappe 28, die Ansaugluftmenge 31 ermittelt durch die Stauscheibe 30 oder einen im elek­tronischen Steuergerät 32 umgeformten entsprechenden Impuls, die Grundeinspritzzeit, den Saugrohrdruck und andere kennzeichnen.The increase in the fuel pressure in the fuel supply line 12 and thus the regulation by the second pressure regulator 44 can also be used to satisfy an increased fuel requirement in certain operating areas of the internal combustion engine despite constant, that is to say not extended, injection times. It may be necessary to increase the fuel injection quantity at full load or acceleration. The possibility of delivery of a fuel excess through Increasing the fuel pressure offers the advantage that an injection valve size can be selected which has a sufficiently large linearity linearity for idling and the lower part-load range and delivers a sufficiently large static fuel injection quantity at full load due to the increase in fuel pressure. If certain values of the operating parameters which characterize the increased fuel requirement are reached, the excitation of the electromagnet 24 is interrupted by the electronic control unit 32 and the control valve 23 closes, so that the regulation of the fuel pressure in the fuel supply line 12 as described above for the hot start or the post-start phase only by the second pressure regulator 44. The speed 35 and a value characterizing the air throughput 31 serve as values characterizing the increased fuel requirement at full load. As soon as these values exceed a threshold value, the electronic control unit 32 interrupts the energization of the electromagnet 24 and the control valve 23 closes, so that the fuel pressure is regulated by the second pressure regulator 44. If these threshold values are then crossed again in the opposite direction, the electromagnet 24 is excited by the electronic control unit 32 and the control valve 23 opens, so that the pressure control of the fuel is now carried out again by the first pressure regulator 19 at the lower level. To identify the increased fuel requirement at full load with the result of de-energization of the electromagnet 24 and to determine the duration of the increased fuel pressure, values of operating parameters can further serve to close an electrical contact in the full load position of a full load switch 40 on the throttle valve 28, the stel tion angle of the throttle valve 28, the intake air amount 31 determined by the baffle plate 30 or a corresponding pulse formed in the electronic control unit 32, the basic injection time, the intake manifold pressure and others characterize.

Die hier dargestellte Erhöhung des Kraftstoffdruckes zum Heißstart, in der Nachstartphase und beim Vorliegen von erhöhtem Kraftstoffbedarf, beispielsweise bei Vollast, erfolgt durch die aufgezeigten Betriebskenngrößen eben­falls bei den Ausführungsbeispielen nach den Figuren 2 und 3 in übertragener Weise. Bei erhöhtem Kraftstoffdruck wird die Einspritzzeit im elektronischen Steuergerät 32 entsprechend den Erfordernissen der Brennkraftmaschine angepaßt.The increase in fuel pressure shown here for a hot start, in the post-start phase and when there is an increased fuel requirement, for example at full load, is also carried out by the operating parameters shown in the exemplary embodiments according to FIGS. 2 and 3 in a transferred manner. When the fuel pressure is increased, the injection time in the electronic control unit 32 is adapted in accordance with the requirements of the internal combustion engine.

Bei dem in Figur 2 in Teildarstellung gezeigten zweiten Ausführungsbeispiel der Erfindung sind die gegenüber den Ausführungsbeispielen nach Figur 1 gleichbleibend und gleichwirkenden Teile durch die gleichen Bezugszeichen gekennzeichnet. Wie beim ersten Ausführungsbeispiel nach Figur 1 führt von der Kraftstoffversorgungsleitung 12 eine Abströmleitung 17 zum Einlaßstutzen 18 des ersten Druckreglers 19, der beispielsweise einen Kraftstoffdruck von etwa 2,5 bar regelt. Der Auslaßstutzen 20 des ersten Druckreglers 19 ist mit der Rückströmleitung 21 verbun­den, in der das Steuerventil 23 liegt, das durch den in oben beschriebener Weise durch das elektronische Steuer­gerät 32 in Abhängigkeit von Betriebskenngrößen der Brenn­kraftmaschine erregbaren Elektromagneten 24 betätigbar ist. Der Einlaßstutzen 46 des zweiten Druckreglers 44 ist über eine Abströmleitung 50 mit der Kraftstoffver­sorgungsleitung 12 verbunden. Der Auslaßstutzen 47 des zweiten Druckreglers 44 führt über eine Rückführleitung 51 zur Rückströmleitung 21 stromabwärts des Steuerventils 23, so daß der etwa einen Kraftstoffdruck von 5 bar re­gelnde zweite Druckregler 44 parallel zum ersten Druckreg­ler 19 liegt. Vorteilhafterweise ist das Steuerventil 23 bei nichterregtem Elektromagneten 24 geschlossen, bei­spielsweise bei den Heißstart, die Nachstartphase und einen erhöhten Kraftstoffbedarf kennzeichnenden Betriebs­kenngrößen, so daß dann der zweite Druckregler 44 wirksam wird und einen Kraftstoffdruck von ca. 5 bar in der Kraft­stoffversorgungsleitung 12 regelt. Nach dem Abschalten der Brennkraftmaschine wird der Elektromagnet 24 ebenfalls entregt und das Steuerventil 23 schließt, so daß sich ein die Dampfblasenbildung ganz oder zumindest wesentlich ver­mindernder Kraftstoffdruck in der Kraftstoffeinspritzanlage aufbaut und ein erneuter Heißstart ermöglicht wird.In the second exemplary embodiment of the invention shown in partial representation in FIG. 2, the parts which are the same and have the same effect as the exemplary embodiments according to FIG. 1 are identified by the same reference numerals. As in the first exemplary embodiment according to FIG. 1, an outflow line 17 leads from the fuel supply line 12 to the inlet connection 18 of the first pressure regulator 19, which regulates, for example, a fuel pressure of approximately 2.5 bar. The outlet port 20 of the first pressure regulator 19 is connected to the return flow line 21, in which the control valve 23 is located, which can be actuated by the electromagnet 24 which can be excited by the electronic control device 32 in the manner described above as a function of operating parameters of the internal combustion engine. The inlet connection 46 of the second pressure regulator 44 is connected to the fuel supply line 12 via an outflow line 50. The outlet 47 of the second pressure regulator 44 leads via a return line 51 to the return flow line 21 downstream of the control valve 23, so that the second pressure regulator 44, which regulates a fuel pressure of 5 bar, is parallel to the first pressure regulator 19. Advantageously, the control valve 23 is closed when the electromagnet 24 is not energized, for example during the hot start, the post-start phase and operating parameters which characterize an increased fuel requirement, so that the second pressure regulator 44 then takes effect and regulates a fuel pressure of approximately 5 bar in the fuel supply line 12. After the internal combustion engine has been switched off, the electromagnet 24 is likewise de-energized and the control valve 23 closes, so that a fuel pressure which completely or at least substantially reduces the formation of vapor bubbles builds up in the fuel injection system and a new hot start is made possible.

Bei dem dritten Ausführungsbeispiel nach Figur 3 sind die gegenüber den bisherigen Ausführungsbeispielen gleich­bleibenden und gleichwirkenden Teile durch die gleichen Bezugszeichen gekennzeichnet wie bisher. Das dritte Ausführungsbeispiel nach Figur 3 zeigt in kompakter Bau­weise einen mit dem ersten Druckregler 19 unmittelbar verbundenen zweiten Druckregler 44. Der erste Druck­regler 19 regelt beispielsweise einen Kraftstoffdruck in der Kraftstoffversorgungsleitung von etwa 2,5 bar, während der zweite Druckregler 44 eine höheren Kraft­stoffdruck von etwa 5 bar regelt. Der erste Druckregler 19 ist aus einem Ventilgehäuse 53 und einer Ventilkappe 54 aufgebaut, wobei am Ventilgehäuse der Einlaßstutzen 18 angeordnet ist. Am Ventilgehäuseboden 55 ist dichtend ein Auslaßstutzen 20 befestigt, der mit einem Ventilsitz­trägerende 56 in einer Kraftstoffkammer 57 des Ventilge­ häuses 53 ragt. In das Ventilsitzträgerende 56 ist ein Ventilsitzkörper 58 eingesetzt, dessen in die Kraftstoff­kammer 57 ragendes Ende einen festen Ventilsitz 59 bildet. Ventilgehäuse 53 und Ventilkappe 54 können als Blech-­Tiefziehteile ausgebildet sein, die durch eine Bördelung 60 verbunden sind, wodurch auch eine Membran 62 quer zur Längsachse des Druckreglers 19 eingespannt ist.In the third exemplary embodiment according to FIG. 3, the parts that remain the same and function the same as in the previous exemplary embodiments are identified by the same reference numerals as before. The third exemplary embodiment according to FIG. 3 shows in a compact construction a second pressure regulator 44 which is directly connected to the first pressure regulator 19. The first pressure regulator 19 regulates, for example, a fuel pressure in the fuel supply line of approximately 2.5 bar, while the second pressure regulator 44 regulates a higher fuel pressure of approximately Regulates 5 bar. The first pressure regulator 19 is constructed from a valve housing 53 and a valve cap 54, the inlet connector 18 being arranged on the valve housing. At the valve housing bottom 55 an outlet 20 is sealingly attached, which with a valve seat support end 56 in a fuel chamber 57 of the Ventilge house 53 protrudes. A valve seat body 58 is inserted into the valve seat support end 56, the end of which projects into the fuel chamber 57 forms a fixed valve seat 59. Valve housing 53 and valve cap 54 can be formed as sheet metal deep-drawn parts which are connected by a flange 60, whereby a membrane 62 is also clamped transversely to the longitudinal axis of the pressure regulator 19.

An der Membran 62 ist zusammen mit einem Federteller 63 eine Halterung 64 befestigt, in der ein Ventilschließ­glied 65 schwenkbar gelagert ist, das eine Verschluß­scheibe 66 und eine mit dieser starr verbundene (verlö­tete) Kugel 67 hat. Die Kugel 67 wird durch eine Halte­scheibe 68 in einer konischen Bohrung 69 der Halterung 64 geführt und wird durch eine in einer Bohrung 70 der Halterung 64 angeordnete Feder 71 an die Haltescheibe 68 gepreßt, so daß ein Schlagen der Verschlußscheibe 66 bei Erschütterungen verhindert wird. Die Verschluß­scheibe 66 bildet zusammen mit dem festen Ventilsitz 59 den Durchflußquerschnitt des Druckreglers. Die Membran 62 trennt die Kraftstoffkammer 57 von einer Federkammer 73 in der Ventilkappe 54. In der Federkammer 73 ist eine Ventilfeder 74 angeordnet, deren eines Ende am Federtel­ler 63 anliegt und das Ventilschließglied 65 in Richtung zum festen Ventilsitz 59 hin beaufschlagt. In die Feder­kammer 73 mündet vorteilhafterweise die Luftleitung 43.A bracket 64 is fastened to the diaphragm 62 together with a spring plate 63, in which a valve closing member 65 is pivotally mounted, which has a closure disk 66 and a ball 67 rigidly connected (soldered) to it. The ball 67 is guided through a retaining washer 68 in a conical bore 69 of the holder 64 and is pressed against the retaining washer 68 by a spring 71 arranged in a bore 70 of the holder 64, so that the locking washer 66 is prevented from being hit by vibrations. The closure disk 66 forms, together with the fixed valve seat 59, the flow cross section of the pressure regulator. The membrane 62 separates the fuel chamber 57 from a spring chamber 73 in the valve cap 54. A valve spring 74 is arranged in the spring chamber 73, one end of which rests on the spring plate 63 and acts on the valve closing member 65 in the direction of the fixed valve seat 59. The air line 43 advantageously opens into the spring chamber 73.

Ein aus dem Ventilgehäuseboden 55 herausragendes Befe­stigungsende 75 des Auslaßstutzens 20 ragt durch einen Topfgehäuseboden 76 eines Topfgehäuses 77 des zweiten Druckreglers 44 und ist derart umgebördelt, daß das Ven­tilgehäuse 53 und das Topfgehäuse 77 fest miteinander verbunden sind. Dem Topfgehäuseboden 76 abgewandet umgreift das Topfgehäuse 77 einen einen Deckel bildenden Flansch 78 des Auslaßstutzens 47 des zweiten Druckreglers 44. Vom Ventilsitz 59 des ersten Druckreglers 19 ausgehend führt eine Auslaßöffnung 79 durch den Ventilsitzkörper 58 und steht mit einem Zuströmkanal 80 in Verbindung, der im Auslaßstutzen 20 des ersten Druckreglers 19 aus­gebildet ist und an einem Ventilsitz 82 endet. Das Be­festigungsende 75 des Auslaßstutzens 20 des ersten Druck­reglers 19 weist eine Sackbohrung 83 auf, aus deren Boden der Ventilsitz 82 herausragt. In die Sackbohrung 83 ragt ein zylindrischer Anker 84 hinein, der einen gerin­geren Durchmesser als die Sackbohrung 83 hat und mit dieser einen Ringraum begrenzt. Der Anker 84 ist fluchtend zum Ventilsitz 82 ausgerichtet und an seiner dem Ventilsitz 82 zugewandten Stirnfläche 85 mit einem Ventilschließglied 86 verbunden, das mit dem Ventilsitz 82 zusammenwirkt. Am dem Ventilsitz 82 abgewandten Ende 87 des Ankers 84 stützt sich eine Schließfeder 88 ab, die andererseits am Auslaßstutzen 47 anliegt. Der Anker 84 ist innerhalb des Topfgehäuses 77 gleitbar in einer Gleitbuchse 89 gelagert, die in ei­ner innerhalb des Topfgehäuses 77 angeordneten Magnet­spule 90 gelagert ist. Der Anker 84 weist an seinem dem Ventilschließglied 86 zugewandten Ende 85 eine Querboh­rung 92 auf, die mit einer Längsbohrung 93 im Anker ver­bunden ist. Die Längsbohrung 93 endet am Ende 87 des An­kers 84. In den Anschlußstutzen 47 kann eine Stellschraube 94 eingeschraubt sein, an der sich das dem Anker 84 abgewandte Ende der Schließfeder 88 abstützt. Durch Verdrehen der Stellschraube 94 kann die Spannkraft der Schließfeder 88 und damit die zur Öffnung des zweiten Druckreglers 44 erforderliche Öffnungskraft eingestellt werden, durch die der vom zweiten Druckregler 44 ge­regelte Kraftstoffdruck bestimmt wird. Die Auslaßöff­ nung 95 des Auslaßstutzens 47 steht mit der Rückström­leitung 21 in Verbindung.An attachment end 75 of the outlet connector 20 protruding from the valve housing base 55 protrudes through a pot housing base 76 of a pot housing 77 of the second pressure regulator 44 and is flanged in such a way that the valve housing 53 and the pot housing 77 are firmly connected to one another. Grips around the pot housing base 76 facing away the pot housing 77 a flange 78 of the outlet connection 47 of the second pressure regulator 44 forming a cover. Starting from the valve seat 59 of the first pressure regulator 19, an outlet opening 79 leads through the valve seat body 58 and is connected to an inflow channel 80 which is in the outlet connection 20 of the first pressure regulator 19 is formed and ends at a valve seat 82. The fastening end 75 of the outlet connector 20 of the first pressure regulator 19 has a blind bore 83, from the bottom of which the valve seat 82 protrudes. A cylindrical armature 84 projects into the blind bore 83 and has a smaller diameter than the blind bore 83 and limits an annular space with the latter. The armature 84 is aligned with the valve seat 82 and, on its end face 85 facing the valve seat 82, is connected to a valve closing element 86 which interacts with the valve seat 82. On the end 87 of the armature 84 facing away from the valve seat 82, a closing spring 88 is supported, which on the other hand rests on the outlet connection 47. The armature 84 is slidably mounted within the pot housing 77 in a sliding bush 89 which is mounted in a magnet coil 90 arranged inside the pot housing 77. The armature 84 has at its end 85 facing the valve closing member 86 a transverse bore 92 which is connected to a longitudinal bore 93 in the armature. The longitudinal bore 93 ends at the end 87 of the armature 84. A set screw 94 can be screwed into the connecting piece 47, on which the end of the closing spring 88 which is remote from the armature 84 is supported. By turning the adjusting screw 94, the tension force of the closing spring 88 and thus the opening force required to open the second pressure regulator 44 can be set, by which the fuel pressure regulated by the second pressure regulator 44 is determined. The outlet 95 of the outlet port 47 communicates with the return flow line 21.

Erfolgt ein Start der Brennkraftmaschine, ohne daß Heiß­startbedingungen vorliegen, so wird durch das elektro­nische Steuergerät 32 der Elektromagnet 24, gekennzeich­net durch die Magnetspule 90, erregt und der Anker 84 und damit das Ventilschließglied 86 vom Ventilsitz 82 entgegen der Kraft der Schließfeder 88 abgehoben, so daß der von der Kraftstoffversorgungsleitung 12 über den Einlaßstutzen 18 zum ersten Druckregler 19 strömende Kraftstoff durch den ersten Druckregler 19 auf einen Druck von ca. 2,5 bar geregelt wird und über den Aus­laßstutzen 20 infolge des geöffneten zwischen Druck­reglers 44 zum Auslaßstutzen 47 des zweiten Druckreglers 44 strömen kann. Beim Heißstart, in der Nachstartphase nach einem Heißstart oder beim Vorliegen eines erhöhten Kraftstoffbedarfes bei Vollast erfolgt in oben beschrie­bener Weise durch das elektronische Steuergerät 32 keine Erregung des Elektromagneten 24, so daß der zweite Druck­regler 44 erst dann öffnet, also das Ventilschließglied 86 vom Ventilsitz 82 abhebt, wenn der Kraftstoffdruck im Zuströmkanal 80 und damit auch in der Kraftstoffver­sorgungsleitung 12 mindestens den Öffnungsdruck des zweiten Druckreglers, also etwa 5 bar erreicht. Um in dieser Situation zu verhindern, daß die Membran 62 des ersten Druckreglers 19 überdehnt wird, ist in der Feder­kammer 73 ein Anschlag 96 angeordnet, an dem sich die Halterung 64 abstützen kann, wenn die Kraftstoffdruck­regelung durch den zweiten Druckregler 44 erfolgt.If the internal combustion engine is started without hot start conditions being present, the electronic control unit 32 excites the electromagnet 24, characterized by the solenoid 90, and the armature 84 and thus the valve closing member 86 are lifted from the valve seat 82 against the force of the closing spring 88, so that the fuel flowing from the fuel supply line 12 via the inlet connection 18 to the first pressure regulator 19 is regulated by the first pressure regulator 19 to a pressure of approximately 2.5 bar and via the outlet connection 20 as a result of the open between pressure regulator 44 to the outlet connection 47 of the second pressure regulator 44 can flow. During the hot start, in the post-start phase after a hot start or when there is an increased fuel requirement at full load, the electronic control unit 32 does not excite the electromagnet 24 in the manner described above, so that the second pressure regulator 44 only opens, i.e. the valve closing member 86 from the valve seat 82 lifts off when the fuel pressure in the inflow channel 80 and thus also in the fuel supply line 12 reaches at least the opening pressure of the second pressure regulator, that is to say about 5 bar. In order to prevent the diaphragm 62 of the first pressure regulator 19 from being overstretched in this situation, a stop 96 is arranged in the spring chamber 73, on which the holder 64 can be supported when the fuel pressure is regulated by the second pressure regulator 44.

Claims (16)

1. Verfahren zum Steuern einer Kraftstoffeinspritzanlage für gemischverdichtende fremdgezündete Brennkraftmaschinen mit einem Saugrohr, mit mindestens einem in Abhängigkeit von Betriebskenngrößen der Brennkraftmaschine Kraftstoff in das Saugrohr einspritzenden Einspritzventil, einer Kraftstoff in eine zu jedem Einspritzventil führenden Kraftstoffversorgungsleitung fördernde Kraftstoffpumpe und einer mit der Kraftstoffversorgungsleitung verbun­denen Druckregelvorrichtung, die einen Elektromagneten hat, der durch ein elektronisches Steuergerät in Abhän­gigkeit von Betriebskenngrößen der Brennkraftmaschine ansteuerbar ist, dadurch gekennzeichnet, daß die Druck­regelvorrichtung einen ersten Druckregler (19) sowie einen zweiten Druckregler (44) hat, daß der zweite Druck­regler (44) einen höheren Kraftstoffdruck in der Kraft­stoffversorgungsleitung (12) regelt als der erste Druck­regler (19), und daß der Elektromagnet (24) nur in vor­bestimmten Betriebsbereichen der Brennkraftmaschine so geschaltet wird, daß die Regelung des Kraftstoffdruckes in der Kraftstoffversorgungsleitung (12) nur durch den zweiten Druckregler (44) erfolgt.1. A method for controlling a fuel injection system for mixed-compression spark-ignition internal combustion engines with an intake manifold, with at least one injection valve which injects fuel into the intake manifold as a function of operating parameters of the internal combustion engine, a fuel into a fuel pump delivering fuel supply line to each injection valve and a pressure control device connected to the fuel supply line, which has an electromagnet which can be controlled by an electronic control unit as a function of operating parameters of the internal combustion engine, characterized in that the pressure control device has a first pressure regulator (19) and a second pressure regulator (44), that the second pressure regulator (44) has a higher fuel pressure in the fuel supply line (12) regulates as the first pressure regulator (19), and that the electromagnet (24) only in total in predetermined operating ranges of the internal combustion engine is switched that the control of the fuel pressure in the fuel supply line (12) is carried out only by the second pressure regulator (44). 2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die Regelung des Kraftstoffdruckes in der Kraft­stoffversorgungsleitung (12) durch den zweiten Druck­regler (44) beim Vorliegen von den Heißstart kenn­zeichnenden Betriebskenngrößen der Brennkraftmaschine erfolgt.2. The method according to claim 1, characterized in that the control of the fuel pressure in the fuel supply line (12) by the second pressure regulator (44) in the presence of the hot start characterizing operating parameters of the internal combustion engine. 3. Verfahren nach Anspruch 2, dadurch gekennzeichnet, daß als den Heißstart kennzeichnende Betriebskenngrößen der Brennkraftmaschine entweder einzeln oder in Kombination Werte der Temperatur des Kühlwassers (34) der Brennkraft­maschine, der Dauer des Startvorganges und der Anzahl der Start-Fehlversuche dienen.3. The method according to claim 2, characterized in that serve as the hot start characteristic operating parameters of the internal combustion engine, either individually or in combination, values of the temperature of the cooling water (34) of the internal combustion engine, the duration of the starting process and the number of failed attempts to start. 4. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die Regelung des Kraftstoffdruckes in der Kraft­stoffversorgungsleitung (12) durch den zweiten Druck­regler (44) in einer Nachstartphase nach einem Heiß­start der Brennkraftmaschine erfolgt.4. The method according to claim 1, characterized in that the regulation of the fuel pressure in the fuel supply line (12) by the second pressure regulator (44) takes place in a post-start phase after a hot start of the internal combustion engine. 5. Verfahren nach Anspruch 4, dadurch gekennzeichnet, daß die Dauer der Nachstartphase von einzelnen Werten oder mehreren der Werte abhängt, die die Temperatur des Kühlwassers (34) der Brennkraftmaschine, die Tempe­ratur der Luft (33) im Ansaugrohr (25), die gesamte Kraftstoffdurchsatzmenge durch das Einspritzventil (11), die Summe der Einspritzzeiten, die Anzahl der Einsprit -­zungen, die Summe der Ansaugluftmenge, die momentane Kraftstoffdurchsatzmenge durch das Ventil (11), die mo­mentane angesaugte Luftmenge (31) und das Produkt aus der Drehzahl (35) der Brennkraftmaschine und einem zur Bildung der Einspritzzeit dienenden Impuls kennzeichnen.5. The method according to claim 4, characterized in that the duration of the post-start phase depends on individual values or more of the values, the temperature of the cooling water (34) of the internal combustion engine, the temperature of the air (33) in the intake pipe (25), the whole Fuel throughput through the injection valve (11), the sum of the injection times, the number of injection tongues, the sum of the intake air quantity, the instantaneous fuel throughput through the valve (11), the instantaneous intake amount of air (31) and the product of the speed (35 ) of the internal combustion engine and a pulse serving to form the injection time. 6. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die Regelung des Kraftstoffdruckes in der Kraft­stoffversorgungsleitung (12) durch den zweiten Druck­regler (44) beim Vorliegen von erhöhtem Kraftstoff­bedarf kennzeichnenden Betriebskenngrößen der Brenn­kraftmaschine erfolgt.6. The method according to claim 1, characterized in that the control of the fuel pressure in the fuel supply line (12) by the second pressure regulator (44) is carried out in the presence of increased fuel consumption characteristic operating parameters of the internal combustion engine. 7. Verfahren nach Anspruch 6, dadurch gekennzeichnet, daß als den erhöhten Kraftstoffbedarf kennzeichnende Betriebs­kenngrößen der Brennkraftmaschine (10) Werte dienen, die die Drehzahl (35), einen zur Bildung der Einspritzzeit der Einspritzventile (11) dienenden Impuls, die Ansaug­luftmenge (31), den Saugrohrdruck (36), den Stellungs­winkel (39) einer im Saugrohr (25) angeordneten Drossel­klappe (28) und das Schließen eines elektrischen Kon­taktes (40) in Vollaststellung der Drosselklappe (28) kennzeichnen.7. The method according to claim 6, characterized in that serve as the increased fuel consumption operating parameters of the internal combustion engine (10) values, the speed (35), a pulse used to form the injection time of the injection valves (11), the intake air quantity (31) , identify the intake manifold pressure (36), the position angle (39) of a throttle valve (28) arranged in the intake manifold (25) and the closing of an electrical contact (40) in the full-load position of the throttle valve (28). 8. Kraftstoffeinspritzanlage für gemischverdichtende fremdgezündete Brennkraftmaschinen mit einem Saugrohr, mit mindestens einem in Abhängigkeit von Betriebskenn­größen der Brennkraftmaschine Kraftstoff in das Saug­rohr einspritzenden Einspritzventil, einer Kraftstoff in eine zu jedem Einspritzventil führenden Kraftstoff­versorgungsleitung fördernde Kraftstoffpumpe und einer mit der Kraftstoffversorgungsleitung verbundenen Druck­regelvorrichtung, die einen Elektromagneten hat, der durch ein elektronisches Steuergerät in Abhängigkeit von Betriebskenngrößen der Brennkraftmaschine ansteuer­bar ist, insbesondere zur Durchführung eines Verfahrens zum Steuern einer Kraftstoffeinspritzanlage nach einem der Ansprüche 1 bis 7, dadurch gekennzeichnet, daß die Druckregelvorrichtung einen ersten Druckregler (19) sowie einen zweiten Druckregler (44) hat und der zweite Druckregler (44) so ausgebildet ist, daß er einen höheren Kraftstoffdruck in der Kraftstoffversorgungs­leitung (12) regelt als der erste Druckregler (19) und nur beim Vorliegen vorbestimmter Betriebskenngrößen der Brennkraftmaschine der Elektromagnet (24) so geschal­tet wird, daß die Regelung des Kraftstoffdruckes in der Kraftstoffversorgungsleitung (12) nur durch den zweiten Druckregler (44) erfolgt.8.Fuel injection system for mixed-compression spark-ignition internal combustion engines with an intake manifold, with at least one injection valve which injects fuel into the intake manifold as a function of operating parameters of the internal combustion engine, a fuel into a fuel supply line leading to each injection valve and a pressure control device connected to the fuel supply line and which has an electromagnet which can be controlled by an electronic control unit as a function of operating parameters of the internal combustion engine, in particular for carrying out a method for controlling a fuel injection system according to one of claims 1 to 7, characterized in that the pressure control device has a first pressure regulator (19) and a second pressure regulator (44 ) and the second pressure regulator (44) is designed such that it regulates a higher fuel pressure in the fuel supply line (12) than the first D Pressure regulator (19) and only when there are predetermined operating parameters of the internal combustion engine, the electromagnet (24) is switched so that the fuel pressure in the fuel supply line (12) is regulated only by the second pressure regulator (44). 9. Kraftstoffeinspritzanlage nach Anspruch 1, dadurch gekennzeichnet, daß stromabwärts des mit der Kraft­stoffversorgungsleitung (12) verbundenen ersten Druck­reglers (19) ein Steuerventil (23) liegt, an dem der Elektromagnet (24) angreift und der zweite Druckregler (44) in einer Bypaßleitung (45) zum Steuerventil (23) angeordnet ist.9. Fuel injection system according to claim 1, characterized in that downstream of the fuel pressure line (12) connected to the first pressure regulator (19) is a control valve (23) on which the electromagnet (24) acts and the second pressure regulator (44) in a bypass line (45) to the control valve (23) is arranged. 10. Kraftstoffeinspritzanlage nach Anspruch 8, dadurch gekennzeichnet, daß der erste Druckregler (19) und der zweite Druckregler (44) parallel zueinander mit der Kraftstoffversorgungsleitung (12) verbunden sind und stromabwärts des ersten Druckreglers (19) ein Steuer­ventil (23) liegt, an dem der Elektromagnet (24) an­greift.10. Fuel injection system according to claim 8, characterized in that the first pressure regulator (19) and the second pressure regulator (44) are connected in parallel to one another with the fuel supply line (12) and downstream of the first pressure regulator (19) there is a control valve (23) which the electromagnet (24) attacks. 11. Kraftstoffeinspritzanlage nach Anspruch 9 oder 10, dadurch gekennzeichnet, daß das Steuerventil (23) bei stromlosem Elektromagneten (24) geschlossen und bei erregtem Elektromagneten (24) geöffnet ist.11. Fuel injection system according to claim 9 or 10, characterized in that the control valve (23) is closed when the electromagnet (24) is de-energized and is open when the electromagnet (24) is energized. 12. Kraftstoffeinspritzanlage nach Anspruch 8, dadurch gekennzeichnet, daß stromabwärts des mit der Kraft­stoffversorgungsleitung (12) verbundenen ersten Druck­reglers (19) der Kraftstoff zu einem Zuströmkanal (80) geführt wird, der am Ventilsitz (82) des zweiten Druckreglers (44) endet, wobei mit dem Ventilsitz (82) des zweiten Druckreglers (44) ein Ventilschließ­glied (86) zusammenwirkt, das durch eine Schließ­feder (88) in Richtung zum Ventilsitz (82) hin beauf­schlagbar und durch die Druckkraft des Kraftstoffes im Zuströmkanal (80) oder einen Anker (84) des Elek­tromagneten (24) entgegen der Kraft der Schließfeder (88) vom Ventilsitz (82) abhebbar ist.12. Fuel injection system according to claim 8, characterized in that downstream of the first pressure regulator (19) connected to the fuel supply line (12), the fuel is guided to an inflow channel (80) which ends at the valve seat (82) of the second pressure regulator (44), A valve closing element (86) cooperates with the valve seat (82) of the second pressure regulator (44) and can be acted upon by a closing spring (88) in the direction of the valve seat (82) and by the pressure force of the fuel in the inflow channel (80) or an armature (84) of the electromagnet (24) can be lifted off the valve seat (82) against the force of the closing spring (88). 13. Kraftstoffeinspritzanlage nach Anspruch 12, dadurch gekennzeichnet, daß der zweite Druckregler (44) am Ven­tilgehäuse (53) des ersten Druckreglers (19) angeordnet ist.13. Fuel injection system according to claim 12, characterized in that the second pressure regulator (44) on the valve housing (53) of the first pressure regulator (19) is arranged. 14. Kraftstoffeinspritzanlage nach Anspruch 12, dadurch gekennzeichnet, daß der Anker (84) des Elektromagneten (24) zylindrisch ausgebildet und an seinem dem Ventil­sitz (82) zugewandten Ende (85) mit dem Ventilschließ­glied (86) gekoppelt und an seinem anderen Ende (87) durch die Schließfeder (88) beaufschlagbar ist.14. Fuel injection system according to claim 12, characterized in that the armature (84) of the electromagnet (24) is cylindrical and at its end facing the valve seat (82) (85) is coupled to the valve closing member (86) and at its other end (87 ) can be acted upon by the closing spring (88). 15. Kraftstoffeinspritzanlage nach Anspruch 14, dadurch gekennzeichnet, daß der Anker (84) in die Magnetspule (90) des Elektromagneten (24) ragt.15. Fuel injection system according to claim 14, characterized in that the armature (84) in the magnet coil (90) of the electromagnet (24) protrudes. 16. Kraftstoffeinspritzanlage nach Anspruch 15, dadurch gekennzeichnet, daß der Anker (84) an seinem dem Ventil­schließglied (86) zugewandten Ende (85) eine Querbohrung (92) und mit dieser verbunden eine Längsbohrung (93) aufweist, die zum der Schließfeder (88) zugewandten Ende (87) hin offen ist.16. Fuel injection system according to claim 15, characterized in that the armature (84) at its valve closing member (86) facing end (85) has a transverse bore (92) and connected to this has a longitudinal bore (93) for the closing spring (88 ) facing end (87) is open.
EP87101603A 1986-03-14 1987-02-06 Method to control a fuel injection apparatus, and fuel injection apparatus Withdrawn EP0237754A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19863608522 DE3608522A1 (en) 1986-03-14 1986-03-14 METHOD FOR CONTROLLING A FUEL INJECTION SYSTEM AND FUEL INJECTION SYSTEM
DE3608522 1986-03-14

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EP (1) EP0237754A1 (en)
JP (1) JPS62218629A (en)
KR (1) KR870009119A (en)
BR (1) BR8701165A (en)
DE (1) DE3608522A1 (en)

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FR2612257A1 (en) * 1987-03-10 1988-09-16 Renault Fuel circuit of an electronic injection system for an internal combustion engine
EP0616120A1 (en) * 1993-03-18 1994-09-21 Bayerische Motoren Werke Aktiengesellschaft Internal combustion engine with lambda control and control valve therefor
ES2120876A1 (en) * 1994-12-09 1998-11-01 Bosch Gmbh Robert Fuel feeder for internal combustion engine
DE10005471A1 (en) * 2000-02-08 2001-08-09 Bayerische Motoren Werke Ag Fuel supply system for IC engine has pressure regulator inserted in fuel line with input control pressure for pressure regulator obtained from feedback line leading to fuel tank
WO2002048532A1 (en) * 2000-12-12 2002-06-20 Robert Bosch Gmbh Method, computer program and control and/or regulation device for operating an internal combustion engine, and corresponding internal combustion engine

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DE19714436A1 (en) * 1997-04-08 1998-10-15 Bosch Gmbh Robert Gas routing system of an internal combustion engine
DE102005001577B4 (en) * 2005-01-13 2017-04-06 Robert Bosch Gmbh Method and device for controlling an internal combustion engine
JP5126538B2 (en) * 2008-12-11 2013-01-23 スズキ株式会社 Vehicle control device

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2612257A1 (en) * 1987-03-10 1988-09-16 Renault Fuel circuit of an electronic injection system for an internal combustion engine
EP0616120A1 (en) * 1993-03-18 1994-09-21 Bayerische Motoren Werke Aktiengesellschaft Internal combustion engine with lambda control and control valve therefor
ES2120876A1 (en) * 1994-12-09 1998-11-01 Bosch Gmbh Robert Fuel feeder for internal combustion engine
DE10005471A1 (en) * 2000-02-08 2001-08-09 Bayerische Motoren Werke Ag Fuel supply system for IC engine has pressure regulator inserted in fuel line with input control pressure for pressure regulator obtained from feedback line leading to fuel tank
WO2002048532A1 (en) * 2000-12-12 2002-06-20 Robert Bosch Gmbh Method, computer program and control and/or regulation device for operating an internal combustion engine, and corresponding internal combustion engine
US7089914B2 (en) 2000-12-12 2006-08-15 Robert Bosch Gmbh Method, computer program and control and/or regulation device for operating an internal combustion engine, and corresponding internal combustion engine

Also Published As

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DE3608522A1 (en) 1987-09-17
JPS62218629A (en) 1987-09-26
BR8701165A (en) 1988-01-12
KR870009119A (en) 1987-10-23

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