US3744460A - Electronic fuel injecting system for internal combustion engines - Google Patents

Electronic fuel injecting system for internal combustion engines Download PDF

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US3744460A
US3744460A US00136002A US3744460DA US3744460A US 3744460 A US3744460 A US 3744460A US 00136002 A US00136002 A US 00136002A US 3744460D A US3744460D A US 3744460DA US 3744460 A US3744460 A US 3744460A
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transistor
switch
capacitor
voltage
output
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L Monpetit
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Societe des Procedes Modernes dInjection SOPROMI
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Societe des Procedes Modernes dInjection SOPROMI
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/32—Controlling fuel injection of the low pressure type

Definitions

  • the shifting from one stage to the other is controlled by two switches constituted byv transistors acting in alternation so as to energize during a predetermined stage a unijunction transistor controlling the starting and stopping of the injection in conformity with a number of parameters stored in memories,
  • the original signals fed into the system are advantageously produced by an oscillator operating for predetermined angular positions of the crankshaft.
  • Such arrangements provide an accurate timing since injection begins when the flip-flop is triggered and the injection duration is determined in accordance with prevailing operative engine condi tions.
  • U.S. Pat. No. 2 ,018, 159 discloses storing, as a first step, of an amount of energy which depends on the operative conditions of the engine, while said energy is released as a second stage step, to control the opening of an electromagnetic injector for a period corresponding to the amount of energy stored.
  • a first switch actuated in synchronism with the rotation of the engine so as to charge a variable condenser through a variable resistance while a second switch then connects the charged condenser with the electromagnetic injectors.
  • a first switch actuated in synchronism with the rotation of the engine so as to charge a variable condenser through a variable resistance while a second switch then connects the charged condenser with the electromagnetic injectors.
  • such an arrangement could not operate reliably or durably since the mechanical contact-pieces wear rapidly.
  • the arrangement as designed could not 5 jectors.
  • the present invention has as its object the elimination of the drawbacks of both above mentioned injection systems by providing an improved arrangement for the electronic control of a fuel injecting system for internal combustion engines including one or more electromagnetic injection valves.
  • the present system is of the type wherein the electric energy controlling the electromagnetic valves and/ or the electric information corresponding to the duration of energization and con sequently to the amount of injected fuel, is stored in a suitable circuit section during a first period of the operative cycle of the engine, said energy and/or the information being then released during a further period of the operative cycle in order to control the injection.
  • the arrangement is constituted by a condenser adapted to store the energy required for injection and/or the information and connected between a constant supply voltage and a vari-' able relatively low voltage supply under control of a first switch as provided by a least one memory and as governed by the operative conditions of the engine.
  • This first switch is connected with means sensitive to the angular position of the crankshaft for controlling the charging of the condenser at the low voltage during the storing period.
  • a threshold element provided with a plurality of inputs is also provided, which is connected on the one hand with the condenser and on the other hand with a supply of a variable positive voltage through another memory, under the control of the operative parameters of the engine, last-mentioned said voltage defining the triggering threshold of said element.
  • the condenser is discharged during the injection period by a second switch which is then released and is locked during the storing period.
  • An amplifier is also provided for the control of the electromagnetic valve or valves and is connected withthe second switch and with the threshold element, said second switch controlling through this last connection the beginning of the injection while said threshold element controls its end when the condenser is discharged down to a certain voltage corresponding to the triggering threshold of said threshold element.
  • the invention is embodied in an arrangeabout 10 milliseconds.
  • the injection period equally spaced by intervals of the same magnitude correspond to the duration of deenergization of the injectors at the end of each injection and more particularly to the duration of recovery of the flip-flop. By reason of such intrinsic properties these systems cannot operate again for the next injection before the end of this recovery period.
  • the detector of the angular position of the engine crankshaft by means of an electronic high frequency oscillator positioned in front of an element governed by the rotation of the engine and including one or more metal screens covering a predetermined angular area said oscillator starting the absence of any screen and stopping whenever a screen registers with the oscillator.
  • the oscillator feeds an impedance matching unit with two outputs, the first of which produces a high voltage level and the second of which produces a low voltage level in the absence of oscillations whereas in the presence of oscillations the situation is reversed It is also provided with a direct output for the oscillations;
  • a programcontrollable uni-junction transistor employs as the threshold element a programcontrollable uni-junction transistor, the anode of which is connected with a condenser, the cathode of which is grounded or else connected with the base of a transistor controlling the end of the injection and and the control electrode of which is connected with the middle point of a voltage divider;
  • a trigger with a plurality of inputs, one input being connected with a first memory defining a first reference voltage for said trigger and the other with the input of the second memory defining a second reference voltage while the output of said trigger is connected with the amplifier controlling the electromagnetic injection valve or valves;
  • switches comprising transistors operating as current generators, which in addition to functioning as switches, also adjust the rate of charging and discharging the condenser;
  • first memory of a voltage divider connected through its terminals with the high level and the low level outputs of the crankshaft angular position detector, said voltage divider being connected through its middle point with the voltage supply through a condenser, said first memory being adapted to store information relating to the rotary speed of the engine;
  • the second memory of a condenser connected between the voltage supply and theoutput of the detector and further connected with a monostable flip-flop triggered by the oscillations at the output of said detector, the width of the output signals of the monostable flip-flop being adjusted in conformity with the operative conditions of operation of the engine by a variable condenser, the second memory being further connected with the collector of a transistor, the emitter of which is connected with the voltage supply and the base of which is connected with the output of the detector, said second memory storing information relating to the load and speed of rotation of the engine.
  • a voltage governing the current flowing through the transistor said voltage being obtained by a capacitory divider including two condensers, one of which varies in accordance with the operative conditions of the engine, said voltage divider being connected with the output of the condenser on the one hand and on the other hand through its middle point with the base of a transistor connected as an emitter follower, the emitter of which is connected with the base of the current-generating transistor through a rectifying diode, filtering resistances and a capacitance, the voltage applied corresponding to the average value of the oscillations, the amplitude of which is defined by the capacitory divider;
  • the detecting oscillator being connected through one of its outputs with the base of said transistor while the charging voltage for said condenser is defined by the voltage divider constituted by a variable resistance and a fixed resistance, a programcontrollable uni-junction transistor being connected between the voltage supply through the variable resistance and the fixed resistance, and the base of a transistor, the control electrode of the program-controllable uni-junction transistor being connected with the slider of a potentiometric voltage divider whereas the point through which the resistances are connected is connected with the anode of the diode through the collector-emitter circuit of a transistor, the base of which is connected with the cathode of the diode and also with the collector through a resistance, the electromagnetic injection valve or valves being controlled by an amplifier including transistors connected with the collector v of said last-mentioned transistor connecting the energy and/or information storing condens
  • an amplifier comprising a transistor, the base of which is connected with the collector of the transistor controlling the end of the injection and is'grounded through a resistance, the base of said transistor controlling the end of the injection being connected with the cathode of the program-controllable uni-junction transistor while its emitter is grounded.
  • FIG. 1 is a block diagram of the arrangement according to the invention.
  • FIG. 2 is a schematic diagram of the electronic control circuit according to a first embodiment.
  • FIG. 3 is a schematic diagram of the electronic control circuit according to a second embodiment
  • FIG. 4 is a schematic diagram of the electronic control circuit according to a third embodiment.
  • the engine 85 provided with an intake manifold 87 is fed with fuel through the injectors comprising by electromagnetic injection valves.
  • the injectors comprising by electromagnetic injection valves.
  • the injection may be provided directly into the combustion chamber of the engine.
  • the injection may be of a mechanical type beyond an electromagnetic injection valve controlled by the amplifier A.
  • the fuel may be injected into the different cylinders of the engine 85 either sequentially in accordance with the sequence of ignitions of the engine with the provision of a suitable distributor which is not-illustrated, or else it may be injected simultaneously in all cylinders.
  • the injectors 20 are fed with fuel under constant pressure conditions by the pump 92 drawing the fuel out of the tank 9l and delivering it into the pipe 93 through the filter 89.
  • the pipe 93 is provided with a 1 a pressure regulator ing the injection in the memories M M and M which.
  • the threshold element T +P is connected with the memories M M M and M, and may also be connected with the detector controlling the end of themjection through operation of the amplifier A.
  • the unit -D is an adaptor shaping the signals, and is used only in conjunction with the embodiment of FIG. 3 and the connections drawn in dashed lines are not essential for all embodiments.
  • FIG. 1 there is illustrated inputs of all the operative parameters into the memory M But, obviously, said parameters maybe introduced into any one of the memories or into all three memories to be distributed in accordance with practical requirements.
  • FIG. 2 there is illustrated a first practical embodiment of the control arrangement wherein the detector D is constitutedby a unit 1 provided with an output 8,, on which a positive voltage appears during the storing period. Said signal is applied to the base of a transistor 2 forming a first switch C and the collector-emitter circuit of which is connected in series with a resistance 6, a condenser 5 comprising the unit M a resistance 4, a diode 3'and another resistance 7 between the voltage supply 23 and ground.
  • the terminal A of the emitter of the transistor is connected'with the voltage supply through the variable resistance 10 forming the memory M defining the charging level of the condensers when the transistor 2 is conductive whereby the terminal A is kept at a voltage V which varies in accordance with the operative conditions of the engine.
  • the point A between the diode 3 and the resistance 4 is connected with a point A through the emitter-collector circuit of a transistor 8 forming a second switch C Said point A, is connected with the base of the transistor 8 and with the collector of the transistor 2 through a resistance 9, with the voltage supply 23 through the variable resistance 11 and withthe anode of a program-controllable uni-junction transistor or threshold unit T P through a resistance 12.
  • the variable resistance 11 forms'the memory M controllingthe charging of the condenser 5 in accordance with the operative condition of the engine.
  • the control electrode of the programcontrollable uni-junction transistor 14 is connected with the slider of a potentiometric voltage divider 21 through a resistance 13, said voltage divider being connected between ground and the resistance 22 connected with the voltage supply 23.
  • This voltage divider forms the memory M, depending also on the operative condition of the engine.
  • the cathode of the programme-controllable uni-junction programcontrollable is connected with the base of a transistor 15 the emitter of which is grounded and the collector of which is connected on the one hand with the base of the transistor 16 forming part of the amplifier A and on the other hand with the voltage supply 23 through resistance 19.
  • the amplifier A further includes transistor 17 connected through its base with the collector of the transistor 16 and also with the voltage supply through resistance 18.
  • the electromagnetic injection valves 20 are connected in series with the emitter-collector circuit of the transistor 17 between the voltage supply and ground.
  • the emitter of transistor 15 is also grounded.
  • the operation of the arrangement is as follows During the storing period a high level signal appears at the output S, of the detector 1 and renders the transistor 2 conductive. Consequently, the condenser 5 is charged under a voltage corresponding to the difference between the voltage V, of the supply of current and the voltage V defined by the voltage divider constituted by the resistances 7 and 10.
  • the charging time constant depends on the resistances 4 and 6 and on the capacity of the condenser 5. During this time, transistor 8 is cut off since the voltage on its base is lower than that on its emitter.
  • the signal at the output S returns to its low level, which cuts off transistor 2. Therefore, transistor 8 becomes conductive since the voltage on its base may rise to the value of the voltage at the point A,.
  • the programcontrollable uni junction transistor which had been conductive is then cut off and condenser 5 discharges.
  • the transistor 15 is also cut off which renders the transistor 16 and 17 conductive and triggers the injection.
  • the condenser 5 during its discharge causes the voltage at the point A, and consequently at the point A, to rise at a rate which depends chiefly on the value of the resistance 11.
  • said programcontrollable uni-junction transistor 14 again becomes conductive which renders the transistor 15 conductive and cuts off transistors 16 and 17, ending the injection.
  • the programme controllable single junction transistor then remains conductive until the next injection is initiated after a further storing period.
  • the duration of the injections thus depends on the charging voltage V, of the condenser 5, as defined by the resistance 10, the discharge speed defined by the resistance 11 and by the reference voltage applied to the control electrode of the programme-controlled unijunction transistor 14, which voltage is adjusted by the voltage divider 21. It is apparent that the resistance 10 acts on the very short storing period, while the resistance 11 and the potentiometer 21 are adapted to act during the injection period. It is therefore possible to select the moment at which the engine parameters are introduced applied according to whether it is preferable to cause their effect during the storing period or during the injection period.
  • engine speed produces its effeet in the case illustrated during the charging of the condenser.
  • duration of the storing signal which is inversely proportional to the speed of rotation of the engine, is larger than about three times the time constant of the circuit charging condenser 5, said condenser is allowed a sufficient for reaching the asymptotic charging value.
  • the charge consequently decreases when the speed of rotation rises above a predetermined limit while the duration of injection is reduced in accordance with the speed of rotation beyond a predetermined threshold.
  • variable resistances for the adjustment of the duration of injection is not an optimum solution when it is desired to execute speedy adjustments as simply as possible.
  • FIG. 3 illustrates a more complete, entirely transistorized circuit.
  • the unit 1 of the detector D comprises more particularly here a conventional electronic high frequency oscillator with the original feature being that it oscillates only when no metal member is to be found in its vicinity.
  • This feature is made use of by providing in front of said unit 1, a rotary unit 86 (FIG. 1) controlled by the rotation of the engine and provided with alternating metallic and nonmetallic sectors. Over a predetermined angular area, the non-metallic sector or sectors cause the unit 1 to oscillate in conformity with the storing period while the metallic sector or sectors produce a stopping of the oscillations during a period corresponding to the injection period.
  • the unit 1 is fed through the resistance 24, the resistances 26, 28, the condenser 25 and the transistor 27 forming an impedance matching adaptor provided on the collector of said transistor 27 with an output terminal S on which the oscillations of the unit 1 are repeated with a difference in phase.
  • the output terminal S is connected with a memory M constituted by a capacitory divider including a constant condenser 37 and an adjustable condenser 38 connected in series between the output S and ground, the connecting point between the condensers being connected with the base of transistor 30 connected as an emitter follower grounded through resistance 41 while its collector is connected with the voltage supply 23.
  • the emitter of the transistor 39 is further connected with the filtering and rectifying circuit constituted by the diode 42, the resistances 43, 45, 47 and the condenser 44, the point connecting the resistances 45 and 47 being connected with the base of the transistor 2 forming the first switch C, controlling the condenser 5.
  • Said condenser 5 is charged through the diode 3, the transistor 2 and the resistance 7 while the charging voltage is defined by the voltage divider constituted by the resistances 7 and 10a and by the voltage applied to the base of the transistor 2 which thus forms the memory M, with said voltage divider 7-104
  • the condenser 5 is discharged through the transistor 50 connected between the voltage supply 23 and the lower terminal of the condenser, together with the resistance 51 and the diode 48.
  • Said transistor 50 is controlled by the transistor 53 the collector of which is connected with the base of the transistor 50 through the resistance 52,the end of which connected with the base of the transistor 50 is also connected with the voltage supply through the resistance 49.
  • the arrangement including elements 49 and 53 forms the switch C and the memory M
  • the tering and rectifying unit constituted by the diode 31, the resistances 32, 34 and 35 and the condenser 33 is adapted to saturate the transistor 36, the emittercollector circuit of which is connected with the resistance 46 between the voltage supply 23 and ground each time the unit 1 in the detector D oscillates.
  • the collector of the transistor 36 is connected with the base of the transistor 53 and, through the resistance 56, with the collector-base connection between the transistors 15 and '16.
  • the program-controllable uni-junction transistor 14 of the threshold unit T P is connected through its anode with the point A,, through its cathode with the base of the transistor 15 and through its control electrode with the point connecting the resistance 21:; and 21b connected in series between the voltage supply 23 and ground so as to form a voltage divider constituting the memory M,.
  • the electromagnetic injection valves 20 are connected in parallel with the protecting diode 55 in the collector-emitter circuit of the transistor 16 forming the amplifier A, between the voltage supply and ground.
  • the base of the transistor 16 in addition to its connection with the collector of the transistor 15 is connected with ground through the resistance 54.
  • the operation of the circuit illustrated in FIG. 3 is similar to that illustrated in FIG. 2.
  • the oscillations after a phase shift appear at the output terminal 8,, of the detector D.
  • the capacitance voltage divider constituted by the condensers 37 and 38 transmits these oscillations to the transistor 39 connected as an emitter follower and the amplitude of these oscillations is adjusted by the variable condenser 38 in accordance with the operative condition of the engine.
  • an average voltage appears on the base of the transistor 2 connected as a current generator.
  • the condenser 5 is then charged through transistor 2 at a rate which depends on the voltage on the base of said transistor 2 and at a level which depends on said base voltage and on the resistances a and 7 in the collector-emitter circuit of the transistor 2.
  • the oscillations at the output terminal S of the detector D are transmitted to the rectifying and filtering means 31, 32, 33, 34, 35 forming the unit D, in a manner such that the transistor 36 is saturated. Consequently the transistor 53 is cut off and so is the transistor 50. Furthermore transistor 16 is cut off by reason of its connection with the unit D, and therefore no injection can take place.
  • the transistor 2 is again cut off as is transistor 36 and the latter ensures conductivity for the transistor 53 and consequently for the transistor 50 connected as a current generator and controlling the discharge of the condenser 5 at a rate depending on the current flowing through transistor 50.
  • transistor 16 is saturated by reason of its connection with the unit D through the resistance 56 and this produces injection.
  • the voltage at the point 'A rises until it reaches a predetermined value with reference to the voltage applied on the control electrode of the program-controllable uni-junction transistor 14, which triggers said transistor 14 and stops the injection since the transistor 15 becomes then conductive and cuts off transistor 16.
  • the transistor 14 remains conductive since the transistors 53 and 50 remain conductive up to the moment at which further oscillations appear at the output terminal 8, and cause the transistors 53 and 50 to be cut off which cuts off the transistor 14.
  • the fundamental regulating parameter such for instance as the reduction in pressure in the admission manifold is transmitted to the condenser 38 which may be of a small capacity and be designed so as to vary inacco rdance with a suitable law with reference to the reduction in pressure.
  • the condenser 38 has rapid response and is suitable therefore for the detection of rapid modifications of a parameter.
  • the memory M introduces again a speed effect as in the case of FIG. 2.
  • the amplifier A may be collected also by means of a connection between the base of the transistor 16 and the middle point of the voltage divider 2la-2-1b of the memory through a resistance and by replacing the resistance 56 by a diode.
  • FIG. 4 illustrates a control circuit constituted by integrated circuits.
  • the detector D includes the oscillator 1 fed through the resistance 24 followed by the filtering and rectifying means constituted by the resistances 26-30-74, the condenser 25-75, the transistor 27 and the diode 73.
  • the electronic gate 2a forming the switch C is connected through its input with the collector of the transistor 27, while its output is connected with the input of the second electronic gate 53a forming the second switch C
  • the output 8,, of gate 2a and the output 8, of the gate 53a form the detector outputs.
  • the level of the output S is low in the presence from oscillations of the oscillator 1 and the level of theoutput S is then high whereas, in the absence of oscillations, the conditions are reversed.
  • the output 8, of the detector D provides a direct connection for the oscillations of the oscillator 1.
  • the output S is connected to one of the inputs of a third gate 64 forming part of the threshold unit T P which further includes a trigger 65 the output g of which is connected with the other input of the gate 64 whereas the inputs e, and e of said threshold unit are connected with the memories M, and M, respectively.
  • the memory M is constituted by the resistances 21c and 21d connected in series between the outputs S, and S, of the detector D with the interposition of the corresponding diodes 63 and 66.
  • Said memory M further includes condenser 57 connected between the voltage supply 23 and the point connecting the resistances 21c and 21d with one another.
  • the memory M comprises integrated bistable flip-flop 59 fed with triggering pulses to form the output 8,, of the detector D and through the condenser 72 during the oscillations of the oscillator 1.
  • the width of the rectangular signals at the output of said flip-flop 59 is adjusted by the variable condenser 60 in accordance with the fundamental regulating parameter of the engine.
  • the flip-flop 59 is connected with a condenser 58 through the diode and the resistance 68, said condenser 58 being further connected with the output S, of the detector D through the resistance 69 and the diode 71 and with the collector of the transistor 61 while its other terminal is fed by the voltage supply 23.
  • the transistor 61 is connected through its emitter with the supply 23 through the resistance 76 and through its base with a voltage divider constituted by the resistances 77-78 connected between the voltage supply 23 and ground, said base being further connected with the output S through the diode 67.
  • the energy-storing condenser is connected between the voltage supply 23 and the output 8 said connection being provided through a resistance 7a and the diode 3.
  • Said resistance 7a forms with the resistance a and the emitter-base circuit of the transistor 2b the memory M which is a voltage divider defining the lower charging voltage of the condenser 5.
  • the resistance 10a is connected with the voltage supply 23 and with the emitter of the transistor 2b the base of which is connected with the point joining the condenser 5 with the resistance 7a.
  • the collector of the transistor 2b is connected through a resistance 62 with the base of the transistor 16 forming the amplifier A.
  • transistor 16 has its collector emitter circuit connected in series with the electromagnetic injection valve 20 between the voltage supply 23 and ground.
  • a protecting diode 55 is connected in parallel with the electromagnetic injection valve.
  • a transistor connected through its base with the output of the gate 64 has its collector-emitter circuit connected between the base of the transistor 16 and ground.
  • the integrated trigger 63 is associated with an identical independent trigger 79, the latter ensuring constancy of the temperature of the circuit.
  • the inputs e and e of said trigger 79 are provided with voltage dividers comprising the resistance 82 and the thermistance 81 for e and two resistances 8384 for e
  • the output 8 of the trigger 79 is grounded through a heating resistance 80 fitted on the frame enclosing the circuits so as to heat them throughout when the thermistance has caused the trigger to change its condition to a temperature below a predetermined limit.
  • the output S is at a low level and the output S at a high level. Further, the monostable flip-flop 59 produces rectangular signals. Consequently, the transistor 61 0f the memory M is cut of? and the condenser 58 is charged through the voltage applied to its lower terminal, as defined on' the one hand by the voltage divider constituted by the resistances 69 and 68 and on the other hand by the rectangular signals produced by the flip-flop 59. The charge on the condenser 58 depends therefore on the number of signals produced by said flip-flop 59 and on their width. A voltage is applied to memory M during this time which corresponds to the charge on the condenser 57 and depends on the duration of the storing period. Consequently, after a predetermined time trigger 65 changes its condition, and produces at its output q a high level signal.
  • the gate 64 Since the gate 64 receives from the output S a low level signal its output is at a high level which renders the transistor 15 conductive and cuts off transistor 16.
  • the condenser 5 is charged at a rate defined by the transistor 2b and the resistance 7a at a voltage level defined by the voltage divider constituted by the resistances 7a and 10a.
  • the output S rises to a high level while the output S falls to a lower level.
  • the output S no longer feeds any pulses to the flip-flop 50 so that its output remains at a high level which biases diode 3 and stops the charging of condenser 58 if this charging has not ceased previously.
  • condenser 58 is discharged through the transistor 61 which has been rendered conductive by the low level signal applied to its base.
  • the voltage applied to the input e, of the trigger 65 consequently rises whereas the voltage applied to the input e, does not vary.
  • trigger 65 returning to its prior condition, which causes a low level signal to appear at its output q and a high level signal to appear at the output of the gate 64.
  • the injection which is taking place is stopped by transistor 15 which becomes conductive and cut off base of the transistor 16.
  • memories M, and M and the unit M act on the injection as a function of engine speed. It is therefore possible, by a suitable selection of the various circuit components, to obtain a duration of injection which in-.
  • condenser 57 is discharged more slowly than the condenser 58 and there is obtained a positive speed effect, that is, the duration of the injection increases. In contradistinction for high rotary speeds, condenser 57 can no longer be charged and a negative speed effect is obtained.
  • the current passing through the injector is governed by the amplifier A, that is by the transistor 16 the base of which is fed by a current depending on the charge of the condenser 5 by reason of the connection between the base of the transistor 2b and condenser 5.
  • the end of injection is however defined by the output signal of gate 64 and consequently no difficulty can arise as far as the closing of the injection valve 20 is concerned.
  • a charging circuit connected to said capacitor including: v
  • a first switch in said charging circuit which when closed enables charging of said capacitor, the level of said charging being a function of the duration of closure of said first switch, and
  • a discharging circuit connected to said capacitor including: I i. a second switch the closing of which permits discharging of said capacitor through said discharging circuit,
  • said discharging causing the voltage at said reference point in said discharging circuit to change to a predetermined reference voltage in relation to the extent of the discharging, said second switch being closed in response to the opening of said first switch and opened in response to the closing of said first switch by said first switch controlling means,
  • threshold means connected to said reference point in said discharging circuit and being responsive to the voltage at said reference point for actuating the fuel metering valve only when said reference voltage is in a predetermined relationship with respect to a threshold level, the value of the threshold being determined by said threshold means, whereby the duration of both the discharging of said capacitor to the predetermined reference voltage and'the actuating of the fuel metering valve are a function of a level of charge obtained during the charging, the extent of discharging, and the value of the threshold level.
  • an amplifier connected to the fuel valve for actuating the valve in response to-an input to said amplifier
  • a three-terminal semiconductor gating element having two main terminals between which current easily passes in a forward direction only when said gating element is fired, and a gate terminal for controlling the firing point of said gate element, the main terminals of said gating element being connected in said forward direction between said reference point and said amplifier for providing said input only when said gating element is firing, and a variable output voltage divider having its output connected to the gate terminal of said gating element for controlling its firing point, the value of said variable output b'eing dependent on the value of a third engine operating parameter,
  • said threshold means comprises:
  • a trigger connected between said reference point and said amplifier to provide said amplifier input when said reference voltage is less than said threshold level
  • threshold-setting means connected to said trigger and responsive to a third engine parameter for determining said threshold level.
  • each of said first and second switches comprise a transistor, which transistors are connected as current generators to control said rates of charging and discharging, respectively.
  • each of said first and second switches comprises an electronic NAND gate.
  • said thresholdsetting means comprises a voltage divider connected between the output of said detector and a low voltage point, the midpoint of said voltage divider connected between said trigger and a source of electric potential via a capacitor.
  • means including a variable capacitor connected to said flip-flop, the value of said variable capacitor determining the breadth of said square waves, the value of said variable capacitor being dependent on said second parameter,
  • said first means comprises a voltage divider conand ground
  • an emitter-follower transistor having its base midpoint of said voltage divider being connected to the terminal of said capacitor nearest ground.
  • Said first Switch comprises a first transistor in. a rectifier-filter circuit connected between the i fi means comprises; emitter of said emitter-follower transistor and the i. a capacitive voltage divider connected between base of Said fi l gn istorthe output of said synchronized control means connected to the midpoint of said capacitive .

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
US00136002A 1970-04-28 1971-04-21 Electronic fuel injecting system for internal combustion engines Expired - Lifetime US3744460A (en)

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FR7015452A FR2088870A5 (enExample) 1970-04-28 1970-04-28

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JP (1) JPS5517215B1 (enExample)
DE (1) DE2120634A1 (enExample)
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GB (1) GB1347712A (enExample)
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3918417A (en) * 1972-10-27 1975-11-11 Gen Motors Corp Electronic fuel injection system
US4092717A (en) * 1975-11-12 1978-05-30 Fiat Societa Per Azioni Method and apparatus for stabilizing the through flow of electromagnetic injectors
US4195599A (en) * 1977-04-25 1980-04-01 The Bendix Corporation Speed sensitive electronic fuel control system for an internal combustion engine

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1564496A (en) * 1975-09-05 1980-04-10 Lucas Industries Ltd Electronic fuel injection control for an internal combustion engine

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3918417A (en) * 1972-10-27 1975-11-11 Gen Motors Corp Electronic fuel injection system
US4092717A (en) * 1975-11-12 1978-05-30 Fiat Societa Per Azioni Method and apparatus for stabilizing the through flow of electromagnetic injectors
US4195599A (en) * 1977-04-25 1980-04-01 The Bendix Corporation Speed sensitive electronic fuel control system for an internal combustion engine

Also Published As

Publication number Publication date
FR2088870A5 (enExample) 1972-01-07
JPS5517215B1 (enExample) 1980-05-09
SE362117B (enExample) 1973-11-26
ZA712335B (en) 1972-01-26
DE2120634A1 (de) 1971-11-18
GB1347712A (en) 1974-02-27

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