US3754537A

US3754537A - Fuel injection system especially for multi-cylinder internal combustion engines

Info

Publication number: US3754537A
Application number: US00231500A
Authority: US
Inventors: W Wessel; J Wahl
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1971-03-12
Filing date: 1972-03-03
Publication date: 1973-08-28
Anticipated expiration: 1990-08-28
Also published as: FR2129349A5; IT950112B; DE2111814A1

Abstract

To provide proper allocation of fuel injected under electronic control, a sequence of electrical pulses, controlled by rotation of the engine are provided, the passage opening electromagnetic valves through which fuel can be injected. A signalling circuit which is inductively or capacitively coupled to an ignition wire provides a signal synchronized with ignition pulses, this signal being coupled to an electronic counter which steps in synchronism with the ignition pulses and the output counts of which control application of the valve pulses to the respective fuel injection valve associated with the cylinders of the internal combustion engine.

Description

United States Patent [191 Wessel et al.

FUEL INJECTION SYSTEM ESPECIALLY FOR MULTl-CYLINDER INTERNAL COMBUSTION ENGINES Inventors: Wolf Weasel, Schwieberdingen; Josei Wahi, Stuttgart, both of Germany Assignee: Robert Bosch, GIIlbI'I,

Gerlingen-Schillerhone, Germany Filed: Mar. 3, 1972 Appl. No.: 231,500

Foreign Application Priority Data Mar. 12,1971 Germany P21 11 814.9

US. Cl. 123/32 EA, 123/32 R Int. Cl F021) 3/00 Field of Search 123/32 EA References Cited UNITED STATES PATENTS 3/1970 Long 123/32 EA Aug. 28, 1973 3,500,802 3/1970 Long 123/32 EA 3,612,011 10/1971 Monpetit..... 123/32 EA 3,702,601, 11/1972 Gordon 123/32 EA 3,032,025 3/1970 Long 123/32 EA Primary Examiner-Laurence M. Goodridge Assistant Examiner-Ronald B. Cox Attorney-Flynn & Frishauf [5 7] ABSTRACT To provide proper allocation of fuel injected under electronic control, a sequence of electrical pulses, controlled by rotation of the engine are provided, the passage opening electromagnetic valves through which fuel can be injected. A signalling circuit which is inductively or capacitively coupled to an ignition wire provides a signal synchronized with ignition pulses, this signal being coupled to an electronic counter which steps in synchronism with the ignition pulses and the output counts of which control application of the valve pulses to the respective fuel injection valve associated with the cylinders of the internal combustion engine.

7 Claims, 7 Drawing Figures PATENTED M 9 23 I975 SHEU 2 (IF 3 FIG. 2

FUEL INJECTION SYSTEM ESPECIALLY FOR MULTI-CYLINDER INTERNAL COMBUSTION ENGINES Cross-Reference to Related U.S. Pats. Nos.

The present invention relates to a fuel injection system for internal combustion engines, and more particularly to a fuel injection system in which electromagnetically operated valves are opened for a predetermined period of time under control of an electric controller, the valves being opened for a predetermined period of time to the supply fuel, under pressure, to the cylinders of electrically fired internal combustion engines. Preferably, the internal combustion engine has a number of cylinders, and the electrical signals which control the opening duration of the fuel injection valves are pulses which are generated in synchronism with the rotation of the engine.

Fuel injection arrangements for example of the types referred to in the cross-referenced patents, usually provide injection valves which are joined in two groups, the injection valves being alternatively operative, and each injection valve being associated with a plurality of cylinders in the multicylinder internal combustion engine. Each injection valve is supplied wiht an operating pulse, usually a square wave pulse, the duration (or pulse with) of which determines the amount of fuel to be injected by a specific valve. An electronic controller provides the pulses for the fuel injection valves. The controller itself is controlled by the operating parameters of the internal combustion engines, such as pressure (or, rather, vacuum) in the intake manifold, engine speed, engine operating temperature, or other ambient and operating temperatures, as detailed in the cross-reference patents. The injection of fuel is triggered in synchronism with rotation of the engine, obtained by a switching device which may be driven, for example, from the shaft which drives the ignition distributor. An additional cam with a single cam rise can be placed on the distributor shaft, the rise of the cam alternately operating one or the other of a pair of switch arms. Slight inaccuracies of the switching time of the mechanical switches do not greatly affect the operation of the engine since more than one cylinder is supplied with fuel during injection of fuel; the actual time of occurrence of the injection is insufficiently in advance of the suction stroke and thus of the subsequent ignition itself. The advance time of injection, before the opening of the suction stroke, is different for the cylinders associated with any one fuel injection valve. If, however, it is desired to associate injection of fuel with the respective cylinders of a multicylinder internal combustionengine, it is of advantage that the fuel injection occur in the same sequence as the ignition, and be associated with a fixed angle of rotation of the crank shaft, in advance of ignition. Thus, it is necessary to provide the triggering signals for the fuel injection valves at a proper phase angle with respect to the instantaneous position of the crank shaft, so that the injection of fuel, and the subsequant operation of the internal combustion engine be correctly matched with respect to time.

It is an object of the present invention to provide fuel injection system in which fuel injection is properly associated with the operation of the various cylinders, and which is free from mechanical contacts.

Subject Matter of the Present Invention Briefly, a signalling circuit is provided which is inductively or capacitively coupled to the ignition system of the internal combustion engine, for example by inductively coupling a signal winding with one or more of the ignition wires. In one example, the signal winding can be placed on a toroidal core, preferably of ferrite, which is slipped over one of the ignition wires. The signalling winding may, however, also be constructed as the secondary winding of a transformer, the primary of which is coupled to one of the ignition winding. Independently of the respective construction of the signal sourceassociated with the signal winding, the signal winding can derive its pulses by coupling with the primary, that is the low voltage circuit, or with the secondary, that is the high voltage circuit of the ignition system of the internal combustion engine, by magnetic coupling. This permits application of triggering signals to the various cylinders utilizing only. electronic techniques. The triggering signals, which derive from the ignition wire of a single cylinder, can be applied to the input of a ring counter which has a count number corresponding to the numger of cylinders of the internal combustion engine. Thus, after the counter has stepped through the counts for all the cylinders, it is reset to the first cylinder. The counter is synchronized by connecting the signalling winding (or another signalling winding) with that count stage of the counter corresponding to the cylinder which is to fire when the counter has activated the specific count number; in other words, since the firing order of sequential cylinders is usually determined by the design of the engine and is not in' sequence of the actual engine construction, the count of the counter has to be associated with a specific cylinder, and the synchronization of the counter is obtained from the ignition wire leading to the spark plug of that specific cylinder.

' The invention will be described by way of example with reference to the accompanying drawings, wherein:

FIG. 1 is a higly schematic diagram of the fuel injection system in accordance with the present invention;

FIG. 2 is a more detailed, schematic diagramillustrating the triggering circuit, the ring counter, and the synchronization circuit in greater detail;

FIG. 2a is a schematic logic diagram illustrating interconnection between ring counter and the distributor circuit; 7

FIG. 3 is a schematic diagram of another embodiment of the signalling circuit, having a transistor switching stage;

FIG. 4 illustrates, in lines T1, T4, T2, T3 a timing diagram schematically illustrating the state of the switching transistors in the ring counter of FIG. 2;

FIG. 5 is a schematic representation of a ring counter for a six cylinder engine; I

FIG. 6 is a schematic representation of a ring counter for an eight cylinder engine.

The present invention will be described specifically in connection with a four cylinder engine. Modification of embodiment described to apply the principles of the present invention to other multi-cylinder engines, such as six or eitht cylinder engines, will be referred to later. A four cylinder engine, generally shown at 10, has four electromagnetically operated fuel injection valves 11, each connected to a fuel valve 13 which derives fuel, such as gasoline, under pressure from a distributor manifold 12. An electrically driven supply pump 15 provides fuel from a tank T to a pressure regulator 16 where fuel under uniform pressure is applied to the manifold distributor 12. The cam shaft, schematically shown at 17, provides, over apparatus to be described, opening pulses schematically shown at 19 and of duration t,, which are square wave pulses, to the several injection valves 1 l. The injection valves must be opened slightly before the suction stroke of the associated cylinder, in the ignition sequence of the internal combustion engine. The duration of opening period t, determines the duration of fuel injection and thus the amount of fuel being injected to a specific cylinder.

The opening pulse 19 is derived by a monostable control multivibrator 20, which has an input transistor 21. Input transistor 21 is normally conductive, and has its collector connected over a resistance 22 with a base of an output transistor 23, normally blocked. A timing circuit, determining the pulse duration t,, in the present example of the control multivibrator, includes a transformer which has a primary winding 24 connected in series with a collector of transistor 23 and collector resistance 25. The secondary winding 27 is inductively connected to the primary winding by means of a movable core 28 which provides a movable coupling element, the position of the core 28 being controlled by the pressure (or, rather, vacuum) in the intake manifold 30 of the internal combustion engine 10. A diaphragm transducer 3l'converts vacuum in the intake manifold to movement of core 28. If the absolute pressure in intake manifold decreases, for example, due to closing of the throttle 32, the core 28 is lifted in the direction of the arrow 31'. As the pressure in the intake manifold 30 increases, the core 28 is dropped, for example, under action of springs (not shown) and thus increases the inductivity of the transformer acting as a timing element. The secondary winding 27 is connected to the junction point P of a pair of

resistances

33, 34, acting as a voltage divider and connected between a chassis or ground bus 35 and a positive bus 26. The other end of secondary winding 27 is connected over a diode 36 to the base of input transistor 21. The emitter of input 21 (which, like output transistor 23 is the npn-type) is connected to the chassis bus 35.

Control multivibrator (which may be much more complicated and built in various types, as referred to in the cross-referenced patents) is not triggered as customary by a mechanical switch, but rather by a trigger circuit 38 which is coupled to the ignition system of the internal combustion engine. Trigger circuit 38 is controlled, in turn, directly by connection to a fixed contact 40 of the ignition breaker 41. The ignition breaker contacts are conventionally arranged in the housing of the distributor 42 which has a four-rise cam 44 secured to the distributor shaft 43, operating the breaker contact springs 41. Additionally, the distributor shaft 43 has the distributor arm 45 which is centrally connected over the main ignition wire 48 with the high tension or secondary winding 46 of ignition coil 47. Upon each pulse of breaker contact 41, ignition potential is distributed to one of four ignition cables, of which only ignition cable 49 is shown, the ignition cable being connected to respective spark plugs 50 of the internal combustion engine. The connections from the distributor to the internal combustion engines of all cylinders but the first have been omitted for clarity from the drawing.

A signal transducer is magnetically coupled to the ignition cable 49 in order to provide a synchronized distribution of the opening pulses 19 derived from the ignition control circuit 20. The transducer essentially consists of a toroidal ferrite core 52 which is slipped over the ignition cable. A signal winding 51 connected at one end to chassis (ground) is wound on the core 52. Winding 51 is used to synchronize an electronic counter 55, connected to triggering circuit 38. Counter 38 has its outputs connected to a multi-channel gated amplifier 56. Counter 55 energizes the specific channel which is associated with the specific fuel injection valve which should be opened at a specific, instantaneous position of the crank shaft (corresponding to a position of the cam shaft 17) in synchronism with the simultaneously triggered opening pulse 19.

Counter 55 is illustrated in detail in FIG. 2, in which the various electronic elements are schematically shown; it can be built as one integrated circuit. FIG. 2 additionally illustrates the construction of trigger circuit 38 and of a synchronizing stage 57.

Synchronizing stage 57 is coupled to the signal winding 51 (FIG. 1) which, in turn, is coupled to the ignition cable 49. Thus, at each four ignition pulses from the ignition coil 47, one pulse will be induced due to the ignition current flowing in cable 49. The other ignition cables may, due to stray fields, interfere with, and create noise in the ignition cable. In order to prevent interference, a second signal winding 58 (FIG. 2) is provided, which is wound on a core 59. Core 59 is slipped over the common ignition cable 48 connecting the ignition coil 47 to the center of the distributor 45. Each of the two

signal windings

51, 58 have an associated diode 61, 62 in series therewith; condensers 63, 46 are connected in parallel with the series circuit formed of the signal winding and the diode. The synchronizing voltages across the condenser 63 together with the compensation voltage across condenser 64 provide the resulting voltage which is applied to the tap point of a voltage divider formed of

resistances

67, 65 and connected between positive bus and chassis bus 90 of the supply. The tap point is further connected to the base of an npn-type transister 66. The emitter is connected to emitter resistance 68 and to the base of an npn-type transister 71, which has an emitter resistance 72. The emitter of transistor 71 is connected to a condenserdiode-resistance network 73 having, in its longitudinal branch connected to the emitter of transister 71, a resistance 74, a diode 75, a condenser 76 and a resistance 77, the resistance 77 being connected to the base of a synchronizing transister (npn-type). The two crossbranches of network 73 are formed by a condenser 78 and a parallel resistance 79, a resistance 81, and condenser 82. Synchronizing transistor 80 has its collector carried to a junction point S and, otherwise, is connected to the positive bus 70 over collector resistance 83.

The triggering circuit 38 includes an npn switching transistor 84 connected with its base to the common chassis bus 90. Its base is connected over resistance 85, likewise to chassis bus 90. A resistance 86, in series with a diode and a resistance 88 connects to a terminal Z (FIGS. 1 and 2), terminal Z being connected to the primary winding 56 of ignition coil 47, ahead of the breaker contact 41. Acondenser 89 connects between resistance 86 and diode 87 and chassis bus 90, so that this condenser will be parallel with both resistances 85, 86. The collector of transistor 84 is connected to the tap point of a voltage divider formed of

resistances

91, 92, connected across the voltage supply. The collector is further carried up to a terminal E, forming the input terminal to ring counter 55 (FIGS. 1, 2). Ring counter 55 essentially includes a pair of bistable multivibrators, each having a pair of transistors, T,, T and T,,, T,. The second multi-vibrator is essentially identical in construction to that of the first multi-vibrator, and, to the extent that the construction is identical, is shown in broken lines only.

Both multi-vibrators are symmetrically constructed, and thus only the circuit in connection with the first transistor T, will be described in detail, since it is identically repeated with respect to the other transistors. Transistor T, (npn) has its collector connected to a terminal A, and to a load resistance 101 which, in turn, is connected to positive bus 70; its base is connected over a base resistance 102 with the common chassis. bus 90. Additionally, the base is connected to the cathode of a diode 103. The anode of diode 103 is connected over a feedback resistance 104 to the collector of the second npn transistor T and a terminal A Second diode 105 is connected to the feedback resistor 104. The cathode of diode 105 is connected to a resistance 106, the other end of which is connected to the positive bus 70. The cathode of diode 105 additionally is connected to a resistance 107 which is one of a group of

resistances

107, 117, 127, 137. Terminals E, and E, appear at the other ends of

resistances

107, 117. Resistance 107, forming a feedback resistance, is connected to the collector of resistor T, of the second multi-vibrator. The cathode vof diode 105 additionally is connected to one electrode of a coupling condenser C,, the other electrode of which is connected to terminal E and from this terminal to the collector of the switching transistor 84 in trigger circuit One of the two transistors T,, T are alternatively conductive in the first multi-vibrator during any one of the operating conditions, the conductive transistor holding the other transistor in blocked state. At the second operating stage, the previously blocked transistor becomes conductive and then holds the other previously conductive transistor in blocked condition. The two transistors T,,, T, operate similarly.

Operation: As soon as breaker contact 41, upon closing the breaker points, touches the fixed breaker contact 40, switching transistor 84 in the trigger circuit 38 becomes conductive and then, in alternate sequence, causes change of state of one of the two rnultivibrators. The alternating change of the operating condition of the transistors is shown inmore detail in the timing diagram of FIG. 4. The upper curve shows the voltage at the collector of the transistor T,; the other curves labeled T,, T T indicate the collector potentials at the respective transistors T,,, T T the sequence being selected for an internal combustion engine which has an ignition firing sequence of cylinders l-4-2-3. The example assumes that transistors T, at the first closing time t, of the breaker is conductive, and thus, that its collector has a voltage which corresponds to voltage 0 of chassis bus 90. Correspondingly,

the collector potential of transistor T, will be in the opposite operating condition, thus close to the voltage of positive bus 70. At the first closing time t,, the first multi-vibrator changes its operating condition, causing transistor T, to block and T to become conductive. At the subsequent closing time t of the breaker, the second multi-vibrator changes its operating state, the previously conductive transistor T being transferred into blocked condition, so that its collector will have positive voltage, whereas transistor T becomes conductive and the collector will be essentially at the voltage of chassis bus 90. At the third closing time t,, of the breakers, the first multi-vibrator switches back to its initial state, transistor T, becoming conductive. The second multi-vibrator is not influenced; only the fourth time does 1,, cause it to revert to its previous state, at which transistor T becomes conductive and transistor T blocks.

The various overlapping operating conditions of the two multi-vibrators can be set forth in the following table; if blocked condition is assigned state ONE, and conductive condition state ZERO, in binary notation, and if a pair of transistors in states ZERO ONE are noted as A, and in state ONE ZERO as B, the relationship will be as follows:

T, and T blocked Position 1 1010 BB T, and T, blocked Position 2 1001 BA T, and T blocked Position 3 0101 AA.

T and T blocked Position 4 0110 AB T and T, blocked Position 1 1010 BB T, and T,, blocked Position 2 1001 BA The cyclical sequance is constrained by coupling

resistances

107, 117, 127, 137. This can be seen in con nection with the explanation which will be given with respect to the operating condition at the first closing time t,, in which transistor T, is conductive, T, is blocked, T is blocked, and T is conductive. (Position 4, in advance of position 1.)

. The collector voltage of transistor T,, is at chassis, and thus the input E connected to the collector of the switching transistor 84 can place positive voltage to the right electrode of coupling condenser C,, so that the right electrode will change with positive voltageYThis is so, since switching transistor 84, until just before the first closing time t,, have been blocked. The other electrode of condenser C, is connected over resistance 107, and the conductive emitter-collector path of the conductive transistor T,, to the negative bus 90, so that it can charge negatively. Coupling resistance 127, assocaiated with the second multi-vibrator, holds the third coupling condenser C,, at negative voltage over the conductive emitter-collector path of transistor T,, so that its other electrode can charge likewise over the input E to the counter and the resistance 92 of the triggering circuit 38 with positive voltage. The voltages at that point are indicated on the diagram of FIG. 2. The two coupling condensers C,, C,, at the first closing time t,, are connected with their positively charged electrodes to negative voltage by the switching transistor 84. The negatively charged electrodes of coupling condensers C,, C,, over coupling resistances 107, 127 apply over

diodes

105, 125, respectively, a highly negative voltage with respect to negative bus 90, on the bases of the two transistors T,, T Transistor T is not influenced thereby since it was already in blocked position at this point of time; transistor T,, however, transfers to blocked condition which puts the collector'of transistor T, at positive voltage. This has the effect that condenser T is connected to positive voltage at both electrodes.

To transfer transistor T at the second closing point T in its blocked condition, coupling condenser C, has to be able to be negatively charged with the electrode connected with the resistance 137 at the period of time t The conductive transistor T enables this switchover, since transistor T, is then blocked, both electrodes of condenser C as noted above, are at positive voltage. Condenser C likewise, has both its electrodes at positive voltage whereas condenser C can charge on its electrode connected to the collector of conductive transistor T, over resistance 107. When transistor 84 at time t becomes conductive, the charge on condenser C has no effect on the already blocked transistor T whereas it will transfer transistor T into blocked condition, which, in accordance with the well-known operation of this circuit causes transistor T to become conductive.

The repeated switching of counter 55 continues cyclically as determined by the closing operation of the breaker contacts. The pulses of the synchronizing circuit 38 are not, however, as yet, associated a specific count condition of the counter with the various cylinders.

The association of the counts to the various cylinders is effected by the synchronizing unit 57 and diodes D,, D connected to the first and third transistors T,, T Diodes D D have cathodes connected to terminal S. When current flows into ignition cable 49, transistor 80 will become conductive, which has as a result that transistor T as well as transistor T are blocked, unless they are already in a blocked state. This forces positioning the counter in position 1 (see above table), so that the counter at the next closing times of the breaker contact, can cyclically step through its count, being reset after position 4 back to position 1, in synchronized rhythm, to continue counting. After synchronization is first obtained, it would be possible to disconnect the synchronizing state. Since triggering of the firing circuit 38 is derived from the primary of the ignition coil, misfirings or gaps in firing will not interfere with stepping of the counter. Leaving the synchronizing state in circuit, however, provides an additional control and supervisory function for increased reliability.

FIG. 3 illustrates an alternative embodiment in which the control multi-vibrator is triggered by a contactless signaling transducer utilizing a small transformer 140, having a primary winding 41 connected between the primary winding 56 of the ignition coil and the

breaker contacts

40, 41 of the distributor. Secondary winding 142 is connected to a

control circuit

145, 146, suitably shielded as schematically indicated at 144. The

lines

145, 146 connect with a firing circuit 148, having a cross connected condenser 147. Firing circuit 148 includes a npn-type switching transistor 154 having a collector connected to the input terminal E of the counter 55 and to the input of the control multivibrator. The base of transistor 154 is connected by means of a diode 151 and a resistance 152, having a condenser 153 connected behind, a resistance 156, and a series circuit formed of

resistance

157, 158 there across the

elements

153, 156, 158 being connected to the common chassis bus 90. The load resistance 159 corresponds to resistance 92 of the firing circuit 38 (FIG. 2) and connects the collector of transistor 154 with the positive bus of the common operating source.

The firing circuit 148 is similar to thatof firing circuit 38 in operation.

Rather than utilizing conductive coupling between the ignition wire 49 and coil 51, capacitative coupling could also be used, for example by placing the conductive element along the ignition wire and suitably connecting this element to transistor 66 of the synchronization circuit.

The outputs from the ring counter are taken from the collectors of transistors T T T T and are indicated at

lines

161, 162, 163, 164. Other suitable points in the counter may be selected These outputs are connected to a logic network (FIG. 2a) which comprises a series of multi-input AND-gates suitably connected in accordance with the table above given, to provide the output at

lines

1, 2, 3, 4, corresponding to the energization of the fuel injection valves of the respective cylinders, in their respective firing orders. The AND-gates may be three-input AND-gates, as shown schematically only with respect to the first AND-gate, having an additional input marked X which can be connected to the output 20' from the control multi-vibrator 20, thus effecting gating function directly with the logic network of the counter; alternatively, the outputs l, 2, 3, 4 can be connected each to an input of a multi-channel amplifier, having an additional input 20' from the control multivibrator for the various channels.

The logic of the output taken from the collector is determined by the firing order of the cylinders. For six or eight cylinders, the counter of FIG. 2 can be expanded as well known in the art; if used with six cylinder engine, the reset must occur after the sixth count, corresponding to six firings, that is, six ignition pulses; for an eight cylinder engine, a binary counter with three groups of multi-vibrators can step completely through eight possible counts. Such counter circuits, and their resets even in advance of the final ultimate count, are well known and need not be described in detail; reference is made, for example, to General Electric Transistor Manual; High Speed Computing Devices (McGraw-Hill, 1950); Scott: Analog and Digital Computer Technology, chapters on Counters and specifically Ring Counters (McGraw-Hill); Pulse and Digital Circuits (McGraw-l-lill 1956), by Millman and Taub.

Various changes and modifications may be made within the inventive concept.

The ring counter of FIG. 5 is a 2 X 3 ring counter; the crossing at the output of the flip flops, only schematically indicated, provides for the reset. The block representation in FIG. 5 of the counter stages correspond, for example, to the full line left half of the circuit of FIG. 2, in which the terminals are labeled similarly to the terminal labeling of FIG. 2.

We claim:

1. Fuel injection system for multicylinder internal combustion engines (10) having an ignition system including an ignition coil (47), a distributor (44, 45), a secondary coil distributor wire (48) connecting the distributor in the secondary circuit of the ignition system, each cylinder having at least one spark plug wire (49) associated therewith and connected to the distributor, and spark plugs (50);

a plurality of cyclically operating fuel injection valves means (20, 56) controlled by the rotation of the engine and connected to said valves to generate, in sequence, electrical pulses (19) to open said valves upon application of the pulse, the duration of a pulse determining the opening period of said valves (1 1 and a signaling circuit comprising a pair of windings (51, 58), one of the windings (51) being coupled to one of the spark plug wires (49) and the other of the windings (58) being coupled to the coil-distributor wire (48) of the ignition system having a pulse appearing there on for each firing of a spark plug of the engine the output of said. signaling circuit being coupled to said pulse generating and connection means (20, 56) to control the distribution of the pulse to the valves.

2. System in accordance with claim 1, wherein (FIG. I) the signaling circuit comprises a toroidal ferrite core (52), the wire carrying ignition passing through the core;

and a winding (5l) wound on the core.

3. System in accordance with claim 1, including rectifier means (61, 62) interconnecting said windings, said rectifier means being oppositely poled to provide mutually blocking rectified potentials from said windings.

4. System in accordance with claim 1, comprising a.

ring counter (55) having a count output corresponding to the number of cylinders and then resetting, the output of the other of said windings (58) being applied to said ring counter; the output of the first of said windings (49) being connected to the counter to synchronize the counter.

5. System in accordance with claim 4, wherein said first winding (51) is coupld to a specific one of the ignition wires (49) of the engine corresponding to a specific cylinder in a specific firing order;

and said winding (51 is connected to the counter at a stage having a count which is representative of the specific one of the fuel injection valves associated with said specific cylinder.

6. System in accordance with claim 4, including a trigger circuit (38) interposed between the signaling circuit and the counter.

7. System in accordance with claim 6, wherein the triggering circuit comprises a switching transistor (84), a voltage divider, the tap point of which is connected to the base of the switching transistor, and a condenser (89) connected across the voltage divider;

and a diode (87) interconnecting the signaling circuit and the counter.

Claims

1. Fuel injection system for multicylinder internal combustion engines (10) having an ignition system including an ignition coil (47), a distributor (44, 45), a secondary coil - distributor wire (48) connecting the distributor in the secondary circuit of the ignition system, each cylinder having at least one spark plug wire (49) associated therewith and connected to the distributor, and spark plugs (50); a plurality of cyclically operating fuel injection valves (11); means (20, 56) controlled by the rotation of the engine and connected to said valves to generate, in sequence, electrical pulses (19) to open said valves upon application of the pulse, the duration of a pulse determining the opening period of said valves (11), and a signaling circuit comprising a pair of windings (51, 58), one of the windings (51) being coupled to one of the spark plug wires (49) and the other of the windings (58) being coupled to the coil-distributor wire (48) of the ignition system having a pulse appearing there on for each firing of a spark plug of the engine the output of said signaling circuit being coupled to said pulse generating and connection means (20, 56) to control the distribution of the pulse to the valves.

2. System in accordance with claim 1, wherein (FIG. 1) the signaling circuit comprises a toroidal ferrite core (52), the wire carrying ignition passing through the core; and a winding (51) wound on the core.

4. System in accordance with claim 1, comprising a ring counter (55) having a count output corresponding to the number of cylinders and then resetting, the output of the other of said windings (58) being applied to said ring counter; the output of the first of said windings (49) being connected to the counter to synchronize the counter.

5. System in accordance with claim 4, wherein said first winding (51) is coupld to a specific one of the ignition wires (49) of the engine corresponding to a specific cylinder in a specific firing order; and said winding (51) is connected To the counter at a stage having a count which is representative of the specific one of the fuel injection valves associated with said specific cylinder.

7. System in accordance with claim 6, wherein the triggering circuit comprises a switching transistor (84), a voltage divider, the tap point of which is connected to the base of the switching transistor, and a condenser (89) connected across the voltage divider; and a diode (87) interconnecting the signaling circuit and the counter.