US3593692A

US3593692A - Electrical fuel injection arrangement for internal combustion engines

Info

Publication number: US3593692A
Application number: US826058A
Authority: US
Inventors: Hermann Scholl; Norbert Rittmannsberger; Wolf Wessel; Wolfgang Rehmann; Josef Wahl
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1968-05-11
Filing date: 1969-05-09
Publication date: 1971-07-20
Anticipated expiration: 1988-07-20
Also published as: NL6906025A; JPS4940580B1; DE1751330B1; CH499014A; FR1602190A; BE732840A; SE339891B; GB1261223A; ES367050A1; DD78430A3; BR6908658D0

Abstract

An electrically controlled fuel injection arrangement for internal combustion engines in which the fuel is injected through electromagnetically controlled valves. A control monostable multivibrator is actuated through a pulse emitter coupled directly to the crankshaft of the engine and emitting pulses synchronously with the speed of the engine. The pulse emitter actuates the monostable multivibrator which has a variable unstable state. A pulse generator coupled to the throttle of the engine emits a sequence of auxiliary control signals which extend the opening time interval of the injection valves during opening motion of the throttle, for purposes of increasing the quantity of injected fuel during engine acceleration.

Description

United States Patent [72] Inventors Hermann Scholl [56] References Cited W UNITED STATES PATENTS f 1; 3,051,152 8/1962 Paule et al. 123/32 EA Wessel, Stuttgart S, Wolfgang Rehmann, 3 504 657 4 1970 h] 2 Stuttgart-Bad CannstatnJosef Wahl, l Cr 123/3 EA Stuttgart-Kaltental, all of, Germany Primary ExaminerLaurence M Goodridge [21] App]. No. 826,058 Attorney-Michael S. Striker [22] Filed May 9, I969 [45] Patented July 20, 1971 [73] Assigncc Robert Bosch G.m.b.H.

Stuttgart, Germany Priority y 11, 1963 ABSTRACT: An electrically controlled fuel injection arrange- Germany ment for internal combustion engines in which the fuel is inl l P 17 51330-3 jected through electromagnetically controlled valves. A control monostable multivibrator is actuated through a pulse 54 ELECTRICAL FUEL INJECTION ARRANGEMENT if to cfinkshafl of the engme and g pu ses sync ronous y wit the speed of the engine. FOR E CPMBPSTION ENGINES The pulse emitter actuates the monostable multivibrator 21 Chums l2 Drawmg Figs which has a variable unstable state. A pulse generator coupled [52] US. Cl 123/32 EA, to the throttle of the engine emits a sequence ofauxiliary con- 123/l l9, 123/l39 E trol signals which extend the opening; time interval of the in- [5 1] Int. Cl F024! 5/02 jection valves during opening motion of the throttle, for pur- [50] Field of Search 123/32, 32 poses of increasing the quantity of injected fuel during engine E,32 EA, 1 l9, 139.18

acceleration.

PATENlfinJuLzmen 3.593.692

SHKEI Bf 5 F76. If

I I I l W FE ELECTRICAL FUEL INJECTION ARRANGEMENT FOR INTERNAL COMBUSTION ENGINES BACKGROUND OF THE INVENTION The present invention resides in an electrically controlled fuel injection arrangement for internal combustion engines having at least one electromagnetically actuated injection valve. The magnetizing coil of the valve is connected in series with a power transistor which is driven by a control multivibrator. This multivibrator is transferred to its unstable state through pulses generator synchronously with the speed of the engine. The injection valves are opened simultaneously with the occurrence of the unstable state of the multivibrator. After a predetermined but variable time interval during which the valves remain open, the multivibrator returns to its stable operating state. The throttle flap of the engine, furthermore, actuates an arrangement which increases the quantity of fuel injected during the opening motion of the throttle flap.

Electrically controlled arrangement of these species, are known in the art for the purposes of injecting fuel into the intake manifold of an internal combustion engine. In such known arrangements, the throttle flap of the engine is coupled to a pulse generator which includes an induction coil and a permanent magnet immersed therein. When stepping upon the gas pedal, the permanent magnet is introduced into the induction coil and thereby induces a voltage within the coil. The magnitude of this induced voltage increases with the opening speed of the throttle flap. In the known arrangement, the induced voltage is applied to a transistor amplifier. With the latter, the reference voltage may be varied for the resetting time and the resulting length of the control pulse of the control multivibrator which provides the reference voltage. In this arrangement, the control pulse becomes extended in length or duration, and this lengthening of the pulse results in increased quantities of injected fuel for purposes of acceleration enrichment.

This conventional arrangement which provides enrichment on the basis of inductance varying with the throttle flap motion, operates satisfactorily for simple injection arrangements. This conventional or known arrangement, however, is relatively complex, because the pulse generator with permanent magnets must be designed with small airgaps and a very high manufacturing tolerance. These conditions apply even when a sufficiently large inductive signal is realized for small or slowly opening movements of the throttle. Pneumatic systems are known in which the pressure rise within the intake manifold of the engine becomes differentiated during the opening of the throttle flap. Such pneumatic arrangements, however, have the disadvantage that the control signal lags the throttle flap motion by approximately 40 to 70 milliseconds.

Accordingly, it is an object of the present invention to provide a fuel enrichment arrangement for accelerating processes, which is simple in design, and which does not lag the motion of the throttle flap. It is a further object of the present invention that the enrichment of the fuel be made dependent upon the opening motion and the opening speed of the throttle flap.

These objects of the present invention are achieved through a pulse generator which is coupled to the throttle flap. This pulse generator delivers a sequence of auxiliary control signals or pulses for the injection valves, during the opening angular movement of the throttle flap. The arrangement is such that the pulse generator provides preferably at least five such auxiliary pulse signals during the opening motion of the throttle flap. The pulse generator may be designed with a switching contact and a switching member cooperating with the contact and rotatable with the throttle flap. The design is arranged so that the switching contact actuates the switching element or circuit element only during the opening motion of the throttle flap.

With such a pulse generator, it is possible, in accordance with the present invention, to provide additional or auxiliary injection processes. Such auxiliary injections of fuel result during the opening motion ofthe throttle flap, and are in addition to the injection processes which results synchronously with the crankshaft rotations of the engine. It is of advantage in such an injection arrangement to provide at least one power transistor in front of which is connected an electronic logical OR gate. The power transistor constitutes the end stage for actuating the electromagnetically controlled valves. The first of the inputs of the OR gate is connected to the output of the control multivibrator which provides pulses synchronously with the rotational speed of the engine. The second input of the OR gate, at the same time, is connected to the output ofa second monostable multivibrator which is independent of the control multivibrator, and which is actuated through the pulse generator coupled to the throttle flap.

SUMMARY OF THE INVENTION An electrically controlled arrangement for the injection of fuel into an internal combustion engine during accelerating states of the engine. The fuel is injected into the intake manifold of the engine, through el-ectromagnetically controlled injection valves which are driven or energized by power transistors. These transistors deliver current to the coils of the injection valve for the purpose of maintaining these valves in the open state. A control multivibrator with stable and unstable states is used to control, in turn, the states of the power transistors. A pulse emitter is electrically connected to the control multivibrator and also to the engine so that it emits pulses synchronously with the speed of the engine. The pulses from the pulse emitter are used to transfer the control multivibrator from its stable state to an unstable state in which the electromagnctically control valves are opened. After a predetermined but variable time interval the control multivibrator returns to its initial stable state. A pulse generator is coupled to the throttle of the engine and emits a sequence of auxiliary control signals, preferably five pulse signals, for opening the injection valve during the opening motion of the throttle. These auxiliary control signals function to increase the quantity of fuel injected into theengine during the opening motion of the throttle, or the accelerating state ofthe engine.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a partial sectional view of the intake manifold of the engine and shows the design for securing the pulse generator to the throttle of the engine, in accordance with the present invention;

FIG. 2 is a partial view of the pulse generator arrangement connected to the throttle of the engine in FIG. 1;

FIG. 3 is another embodiment of the pulse generator shown in FIG. 2;

FIG. 4 is an isometric view of a further embodiment of the pulse generator connected to the engine throttle in FIG. 1;

FIG. 5 is a diagrammatic plan view and shows the detail of the stationary and movable contacts used in the pulse generator of FIG. 4;

FIG. 6 is a partial sectional view through the driving shaft of the pulse generator of FIG. 4;

FIG. 7 is an electrical schematic diagram ofa fuel injection arrangement for electrically controlling the injection of fuel into an engine, in accordance with the present invention;

FIG. 8 is a waveform diagram of pulse signals in the circuit of the embodiment of FIG. 7;

FIG. 9 is an electrical schematic diagram of a second embodiment of an electronic fuel injection arrangement, in accordance with the present invention;

FIG. is a waveform diagram of signals associated with the circuitry of the second embodiment of FIG. 9;

FIG. 1] is an electrical schematic diagram of a further fuel injection arrangement; and

FIG. 12 is a waveform diagram of the signals associated with the circuitry of FIG. 11.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawing, and in particular to the first embodiment shown in FIGS. 1 and 2, a throttle flap or valve member 2 is rotatably mounted on a shaft 3 within the intake manifold l of the internal combustion engine, in accordance with the present invention. The shaft 3 of the throttle flap valve member projects, with its ends, beyond the shaft bearings 4 and S. A lever 6 is mounted upon the end of the shaft 3 projecting through the bearing 4 of the intake manifold 1. The lever arrangement 6, furthermore, is joined to a connecting rod 7 which, in turn, is coupled to the gas pedal, not shown, of the internal combustion engine. Through means ofa return spring, the lever arrangement 6 may be acted upon to rotate the shaft 3 so that the throttle flap member 2 is in the open position, as shown in the diagram of FIG. 1.

A gear 8 is mounted upon the end of the shaft 3, projecting from the bearing 5. A lever 9 is, furthermore, securely fixed to the throttle flap shaft 3. The free end of the lever 9 carries a pawl 10 which is acted upon by a spring, not shown. The teeth of the gear 8 have the profile of ratchet teeth which engage the pawl 10. The ratchet teeth and engaging pawl are oriented so that the ratchet 8 may be rotated through motion of the pawl 10 only when the lever 9 carrying the pawl 10 rotates in the direction of the arrow shown on the ratchet wheel 8 in FIG. 2.

Leading to the outside of the intake manifold l, are two strip-shaped contact-carrying members 12 and 13 made of preferably red brass or tombac which is a copper-base zinc alloy.

Contacts

14 and 15 are provided at the free spring ends of the blades or members 12 and 13 which are electrically iso lated from each other. Furthermore, at least one of the contact carrying members 12 and 13, is electrically isolated with respect to the intake manifold 1. The contact-carrying member or blade 13 has a tongue portion 16 projecting from the location at which the respective contact 15 is secured. This tongue portion or blade 16 operates in conjunction with the ratchet teeth of the ratchet wheel 8. When the ratchet wheel 8 is rotated in the direction of the arrow shown in FIG. 2, through motion of the pawl 10 when opening the throttle flap, the tongue portion 16 moves toward the carrying blade 12 and thereby causes the

contacts

14 and 15 to produce briefly a closed circuit. Closure of the

contacts

14 and 15 is accomplished whenever the ratchet wheel 8 is rotated through an angle which corresponds to the pitch distance of one tooth of the ratchet wheel. In the embodiment being described, an angle of 90 is rotated or traversed when the throttle flap 2 becomes fully opened. During this angular interval of 90, the contacts Hand 15 will close, thereby, eight times. The construction of the tongue portion or blade 16 in relation to the ratchet wheel 8 is such that the latter is prevented from rotating against the direction of the arrow shown in the drawing, when the throttle flap is returned to closed position. Thus, the tongue blade or portion 16 engages the ratchet teeth such that rotation of the ratchet wheel in the direction opposite to that shown by the arrow in FIG. 2 is inhibited. Accordingly, electrical impulses are generated only when the throttle flap is opened. These pulses derived through the closure of the

contacts

14 and 15 are not generated when the throttle valve is being closed. The pulses are generated for use in conjunction with accelerating features.

In a different embodiment shown in FIG. 3, the shaft 22 is rotatably mounted in bearings ofthe intake manifold of the internal combustion engine. The shaft 22 has mounted onto it the throttle flap, not shown. A gear segment 23 is secured to one end of the shaft switches 101 projecting to the outside or exterior of the intake manifold. A contact-carrying member 25 is secured to the intake manifold 21 and is arranged to lie opposite the gear tooth segment. When the segment 23 is rotated in the direction of the arrow shown on the segment, in FIG. 3, the contact-carrying member 25 becomes engaged by the teeth of the segment and is brought into contact with a second member 26. The gear segment 23 will rotate in this direction of the illustrated arrow when the throttle flap mounted on the shaft 22 is being opened. As a result of bringing together the

members

25 and 26 through the action of the gear segment 23, the

contacts

27 and 28 on the

members

25 and 26, respectively, form a circuit closure. Through such circuit closure, therefore, an enrichment pulse for the electronic control arrangement associated with the fuel injection structure, may be realized.

In the embodiment of FIG. 3, in accordance with the present invention, the

contacts

27 and 28 produce a circuit closure whenever the segment is rotated through an angle which corresponds to a single tooth pitch. Such circuit closure between the

contacts

27 and 28 is established whenever the segment is rotated in the direction of the arrow, corresponding to opening of the throttle flap or valve. When, on the other hand, the throttle flap is rotated for the purpose of closing the throttle, the segment 23 is rotated in the direction opposite to that shown by the arrow, and the contact carrying member 25 is carried or moved by the teeth of the segment, so that the member 25 moves away from the member 26. Once a tooth of the segment 23 intercepts the member 25 and moves it away from the member 26, the member springs back to its original position after release by the intercepting gear tooth when the latter has moved through a tooth pitch distance. Through proper design of the teeth of the gear segment 23 in relation to the member 25, it is possible to achieve the feature whereby the member 25 becomes caught by the next oncoming tooth upon release by any given tooth. Thus, when the member 25 becomes released by any given tooth when the latter moves in the direction opposite to that of the shown arrow, and the member 25 proceeds thereafter to snap back to initial position, a member 25 becomes caught by the next oncoming tooth. As a result of this action, the

contacts

27 and 28 are prevented from coming into electrical contact with each other when the member 25 snaps back upon release of the intercepting tooth of the segment 23. With this arrangement, therefore, it is possible to achieve the feature whereby enrichment pulses are generated through closure of the

contacts

27 and 28, only when the throttle is being opened.

A third embodiment of the present invention is shown in FIGS. 4 to 6. In this embodiment, the throttle flap 32 is mounted upon a carrying shaft 33. A bearing member 34 is held to the shaft 33, through means ofa leaf spring 35 pressing against a flattened portion or zone 36 on the shaft 33. An intercepting or gripping nose 37 is secured to the bridge 34. This intercepting member 37 reaches freely into a recess portion 38 of an insulating disc 39. The insulating plate 39 carries two closely located contact members 40 and 41, which extend angularly beneath the plate. The upper portion of these contact members 40 and 41 terminate into two contact springs 42 and 43 facing towards the bearing member 34. In the vicinity of their free ends, the contact springs are provided with two contacts 44and 45. An insulating member 48 is secured to a carrying arm 47 located diametrically opposite to the intercepting or nose member 37. The insulating member 48 is mounted at the height of the contact springs. The insulating member 48 forms, together with the two contacts 44 and 45, a drag switch 50 which becomes closed as a result of the insulating member 48 riding upon the contact spring 42. Such closing action of the insulating member 48 is realized when the throttle flap 32 swings or rotates in the direction of the arrow A. In this direction of the flap 32, the throttle becomes opened. The necessary contact pressure is realized through a carrying hub 54 which serves as a brake. The hub 54 of the insulating plate 39 has a notch surrounded by a spring clamp member 51 which, in turn, has a lug slided over a pin member 52 seated in the base plate 53 of the pulse generator. This base plate carries to

leaf springs

55 and 56 which are insulated from each other, and which are provided with

contacts

57 and 58 at their free ends. In the idling position of the engine, corresponding to the closed position of the throttle flap 32, the

contacts

57 and 58 are retained in closed circuit position through the insulating member 48 bearing or pressing against the oppositely lying leaf spring 55. When, once the throttle flap is moved from its idling position, the contacts become open or are transferred to circuit open position. The open circuit state of the

contacts

57 and 58 is realized as soon as the throttle flap is moved only by a small amount from its idling position. For the purpose of adjusting the opening point of the contacts to the optimum location of this idling switch in relation to the throt' tle flap 32, elongated slots 59 are situated concentrically with respect to the axis of the throttle shaft 33. By passing bolts through these elongated slots 59, the base plate 53 may be ad' justed in position and secured to a casting 60 on the intake manifold 31.

Three contact tracks 61, 62, and 63 are deposited upon a nylon plate 65, concentric with the rotational axis of the throttle shaft 33. These contact tracks are provided for the purpose of producing enrichment pulses during the opening of the throttle flap, and are provided in addition to the two contact members 40 and 41 of the drag switch. The contact member 41 may slide along the inner contact track 61, when the insulating plate 39 together with the throttle flap 32 is rotated into opening position of the latter. The second contact member 40 is thereby alternatingly brought into contact with one or the other of the two exterior or

outer contact track

62 and 63. These two contact tracks are designed so that each has nine

cross-stages

66 and 67, which is greater than the number shown in the drawing. Thus, each of the

tracks

62 and 63 is provided with

transverse portions

66 and 67, respectively, which interleaf alternatingly. The contact member 10, therefore, will contact the

portions

66 and 67 in an alternating manner and thereby provide the required number of pulses. The larger the number of these transverse portions or crossstages 66 and 67, the more sensitive is the pulse generator for small opening motions of the throttle flap. An advantageous design is realized when the spaces or gaps between neighboring cross-stages or

transverse portions

66 and 67 are larger than the contact surface 68 in the sliding direction across these

transverse portions

66 and 67. in this manner, unin tended oscillations of the gas pedal resulting from small vibrations of the motor vehicle and produced by the driver, do not result in the emission of signals.

For the purpose of avoiding error problems, the outer contact track 63 may, as described in a practical example below, be connected to one of two inputs of a bistable transistorized multivibrator. The central contact track 62, at the same time, may be connected to the second input of the multivibrator, and the inner contact track 61 may, for example, be connected to ground potential so as to form a switching arrangement. In this arrangement, the multivibrator becomes switched in state not when the contact finger or member leads a cross-stage or transverse portion, but instead the multivibrator first changes state when the contact finger or contact member moves onto a neighboring transverse portion or cross-stage to which the other multivibrator input is connccted.

The drag switch 50 opens in the closing direction of the throttle flap 32 and as a result of the rotational action between the nose portion 37 and the cross section 38. This state of the drag switch 50 in which it opens, takes place before the insulating plate 39 can follow with the insulating member 48 and the bearing member 34. The insulating plate 39 is braked from the spring clamp 51. As a result of this action, enrichment pulses are generated only during the opening of the throttle flap or valve. The generation of such enrichment pulses, on the other hand, is suppressed in the closing direction of the throttle valve, through the contacts 44 and 45 of the drag switch, which are then in the open state.

The injection arrangement in accordance with FIG. 7 of the present invention, is designed for operation in conjunction with a remotely ignited four-cylinder, four-cycle internal combustion engine. This fuel injection arrangement shows a preferred embodiment for the signal generator of FIGS. 4 to 6. Four cleetromagnetically actuated injection valves are associated with the injection arrangement. Two of these valves 1111 and 1211 inject simultaneously. Assume that the internal combustion engine has a l-lV-lll'Il ignition sequence. In that case, the electromagnetically operated valves of the first and fourth cylinder belong to the first valve group 110, whereas the electromagnetically operated valves for the third and second cylinder belong to the valve group 120. Thus, the coils 110 and 121) each represent diagrammatically groups of electromagnetically operated valves. The fuel injected by the electromagnetically operated valves of the two

groups

110 and 120, is applied to the valves by an electrically operated pump which maintains the pressure constant at two atmospheres.

A PNP power transistor 111 is associated with the valve group 110, whereas the power transistor 121 is associated with the valve group 120. These two power transistors 111 and 121 are driven by driving transistors 112 and 122, respectively. The combination of the transistors 1112 and 111 form an end stage 113, whereas the transistors 121 and 122 form a second end stage 123.

The injection valve groups must be brought alternatingly into their open positions in relation to the crankshaft rotation of the engine. This feature is accomplished through two

switches

101 and 102 arranged in an ignition distributor, not shown. These two switches are operated through cams which have actuating portions displaced 180 from each other. Accordingly, the

switches

101 and 102 are closed through these cams at 180 displacements. The two switches operate in conjunction with a bistable multivibrator 130 which includes two NPN transistors 131 and 132. The emitters of these two transistors are both joined to the negative voltage supply line 100. Each of the collectors of these two transistors lead to the positive supply line through a separate resistor. Thus, the collector of the transistor 131 leads to the supply line by way of resistor 133, whereas the collector of 132 is associated with the resistor 134. Furthermore, the base of transistor 131 is connected to the collector of transistor 132 through a feedback-coupling resistor 135. Such a similar feedback resistor 136 is connected between the base of the transistor 132 and the collector of transistor 131. Of the two transistors 131 and 132, that one is in nonconducting state, which is associated with the switch that was previously closed and which is connected in parallel with the emitter-base path of the transistor. This transistor then remains in this cutoff or turned-off state until the other switch associated with the other transistor becomes closed through the further operation of the cam. The switches 101 and 1112 do not determine, however, the duration of the injection processes of the valve groups and 120. These switches, instead, are criteria for establishing when and which of the two groups or valves are to be brought in their opening position. The quantity of fuel injected into the intake manifold of the engine during each injection process, is proportional to the duration of rectangular-shaped control signals. These control signals are produced at the output of a control multivibrator 151) which is shown in the drawing in considerably simplified form. The pulse signals are produced for each closure of the

switch

101 and 102. The control multivibrator includes an input transistor 151 and a transistor 152 which is an output transistor with base-connected to the collector of the transistor 151. The two transistors are of the NPN type. In the control multivibrator 150, which is shown in illustrative form, a transformer 153 is provided for the purpose of matching or fitting the duration of the control pulses. This transformer 153 in the form of an inductive timing element, has a primary winding 1541 connected in series with a resistor 155. The series combination of these two elements 154 and 155, is connected between the collector of the transistor 152 and the positive voltage supply line 90. The primary winding 154 is coupled to the secondary winding 156 through an adjustable ferromagnetic core 157. The circuit arrangement is such that through this transformer, the collector of the transistor 152 is coupled to the base of the transistor 151. The adjustable ferromagnetic core 157 is connected through mechanical linkage, to a pressure-sensing membrane located within the intake manifold and behind the throttle flap of the engine in the intake direction. When the pressure prevailing within the intake manifold drops, so that the absolute pressure decreases, the adjustable core 157 is drawn from the transformer, by predetermined amounts, to thereby reduce the inductance of the transformer.

The base of the transistor 151 is connected to the collector of the transistor 132 of the signal generator 130 through a decoupling diode 159 and a capacitor 144. A similar decoupling diode 158 and capacitor 145 is connected between the base of the transistor 151 and the collector of the transistor 131. The capacitors 144 and 145 serve dif ferentiating elements. These differentiating elements reside within the differentiating circuits 140 in which resistors 141 and 142 are connected to the negative voltage supply line 100. The resistor 141 is connected to the capacitor 145, whereas the resistor 142 is associated similarly with the capacitor 144. For every closure of the switch 102, a signal 146, as shown in the drawing, is realized for the control multivibrator 150. The signal results through the condition that the transistor 131 becomes conducting and the base potential of the input transistor 151 becomes negative in relation to the negative supply line 100 as a result of the previous tumed-off state of the transistor 131 and the charge of the capacitor 145 through the diode 158. This negative potential of the base of the transistor 151 is such that the input transistor which was turned on to that instant, becomes turned off and, at the same time, the turned-off output transistor becomes turned on. The collector current of the output transistor associated with the primary winding 154 of the transformer 153, then produces a feedback voltage signal within the secondary winding 156. This voltage signal within the secondary winding 156 retains the input transistor 151 turned off through the transition interval. The input transistor 151 is, in fact, held turned off untilthe voltage has dropped to a minimum value determined by the setting of two resistors 161 and 162 connected to form a voltage divider. The input transistor 151 then returns to its stable conducting state and, at the same time, turns off the output transistor 152.

A logical AND gate 115 is connected in front of the power stage 113, while a similar AND gate 125 is connected in front of the power stage 123. These AND gates assure that the control pulses initiated through the closure of the

switches

101 and 102 become selectively applied to the

valve groups

110 and 120. The AND gate 115 has an NPN transistor 116 which has its base connected to the collector of the signal generator transistor 132, by way of the base resistor 117 and the conducting path l18. The AND gate 125, on the other hand, has a transistor 126 with base connected to a resistor 127 leading to the collector of the transistor 131 by way of the conducting path 128. The transistors 131 and 132 are associated with the signal generator 130. The bases of the two transistors 116 and 126, furthermore, are connected by way of second base resistors 119 and 129, respectively, to the collector of a further transistor 163. The base of the transistor 163 is connected to a noncrucial stage 170, so that the transistor becomes turned off in the interval between two of the pulses delivered by the control multivibrator 150. The transistor 163, however, will turn off or cut off only that one of the AND

gates

115 and 125 which also has, at the same time, the respective one of the transistors 131 and 132 in the conducting state. The AND gate which is operated in this manner, then cuts off the injection process of the

respective valve groups

110 and 120.

In operation of the circuitry with relation to the timing diagram shown in H6. 8, the switch 102 becomes closed at the time instant 1,. The transistor 132 is then transferred to its turned-off state, whereas the other transistor 131 becomes LII conducting. The AND gate'12'5 is thereby brought into its switched-off state in conjunction with the simultaneously delivered control pulses from the multivibrator 150. The AND gate 125 maintains this switched-off state until the termination of the control pulse delivered by the control multivibrator 150. hi this sv/itched'off state of the AND gate 125, the power stage 123 is held in the conducting state for producing an opening pulse for the valve group 120. As soon as the control pulse is terminated at the instant t the transistor 163 turns to its turned-off state and terminates the injection process through turning off the power stage 123. This operational sequence takes place even though an opening signal for the valve group 120 prevails at the AND gate 125 until the final instant of time t of the switch 101. Such opening pulse is not, however, effective since the transistor 131 as well as the transistor 163 would have to be both conducting.

The next injection process is initiated at the valve group at the instant 1,, through the then closing switch 101. The transistor 132 thereby transfers to the conducting state and the input transistor 151 of the multivibrator 150, moreover, becomes turned off through the differentiating capacitor 144 for the duration of the next control pulse determined by the position of the ferromagnetic core 157. The injection process for the valve group 110 becomes terminated with the expiration of the control pulse at the instant 1, The next injection process can then result through an injection arrangement which is constructed similar to that already described, by closure of the switch 102 at the instant i The two AND gates and operate, in conjunction with the bistable signal generator 130, in the form of an electronic distributor. They make possible to drive the fuel injection arrangement such that enrichment pulses are applied for acceleration purposes when the throttle flap is moved towards or into the opening direction. This is in conjunction with the injection processes resulting synchronously with the rotations of the crankshaft, and the injection pulses are inserted in the form of intermediate pulses. For the purpose of realizing a number of control signals which is proportional to the opening path of the throttle flap, a pulse generator is designed as shown in H65. 4 to 6. The contact springs of a switch functioning as a drag switch are designated by the two contacts 44 and 45. One of these contacts is connected to the negative voltage line 100, whereas the other one is connected to the contact finger or spring 40 which is shown schematically in H0. 7 as a switching on. This contact spring 40 rides over the cross-stages 66 and 67 during the opening motion of the throttle flap, and thereby makes contact alternatingly and in a rapid manner with the two outer contact tracks 62 and 63.

The two outer contact tracks 62 and 63 are applied to the bases, respectively, of the

transistors

232 and 231 which are associated with a second bistable multivibrator 230. This multivibrator is constructed similarly to the signal emitter or generator 130. This multivibrator differs from the former unit 130, however, in that it will change rapidly between its stable states only when the contact tracks 62 and 63 are brought rapidly into connection with the negative voltage supply line 100 while the drag switch is closed, and during the opening movement of the throttle flap.

In the diagram of FIG. 8, it is assumed that at the instant of time the throttle flap becomes opened from its previous stationary opening angle a, of approximately 25 for a rotational speed n=2000 revolutions per minute of the engine. The throttle flap becomes opened from this stationary angle within one twentieth sec. =50 m. sec. corresponding to approximately 45. The contact fingers or springs thereby ride over the crossstages 66 and 67 with essentially constant velocity. Thus, during this opening movement of the throttle flap, the contact springs transverse nine times one of the cross-stages 66 and 67. The bistable multivibrator 230 is thereby brought to its opposite stable state.

Capacitors

244 and 245 are connected, respectively, to two

diodes

248 and 249. These capacitors form differentiating circuits with the

respective resistors

241 and 242, similar to the differentiating circuits 140' described above. These differentiating circuits are connected through one electrode of the

capacitors

244 and 245, to the collectors, respectively, of the

transistors

231 and 232. These two transistors are associated with a monostable multivibrator 250. This monostable multivibrator delivers an intermediate pulse Z of approximately 2.2 milliseconds for every transfer of state or switching process of the bistable multivibrator.

Referring to FIG. 8, the first intermediate pulse begins at the commencement of the opening motion of the throttle flap at the instant of time 1 The second intermediate pulse is generated or appears 6 milliseconds later at the instant of time For the purpose of generating this intermediate impulse Z at substantially constant pulse duration, the base of the transistor 251 leads to the positive supply line 90, through a diode 259 and resistor 258. The collector of this transistor 251 is, furthermore, connected through a coupling resistor to the base of an NPN type of transistor 252. The collector of this transistor 252 is coupled to the base of the transistor 251 through a timing capacitor 257 of approximately 0.07M. In the quiescent state, the input transistor 251 is conducting and maintains the transistor 252 turned off. The input transistor 25], however, is turned off through the charge upon the differentiating

capacitor

244 or 245 as soon as the bistable multivibrator 230 switches states, as a result of contact finger 30 riding upon the next cross-stage or transverse portion of the contact tracks. The input transistor 251 is maintained in this tumed-off state for the duration of the intermediate pulse Z, and until the charge upon the capacitor 257 has become equalized through the resistor 258 and the collector resistor 255 of the second transistor 252.

The aforementioned transistor 163 is arranged in the form of an OR element 165 so that the intermediate pulse Z may be applied to one of the two

valve groups

110 or 120 for additional injection processes. The base of the transistor 163 is connected, on one hand, to the intermediate stage 170, through the resistor 166. At the same time, the base of this transistor 163 is connected to the collector of the transistor 251, through the resistor 168. A third resistor 167 is connected between the base of this transistor 163 and the negative voltage supply line 100. This resistor 167 assures that the transistor 163 remains turned off for as long as either an intermediate pulse Z lies at its base, or a control pulse .l derived from the monostable multivibrator 250 or from the control multivibrator 150 by way of the intermediate stage 170. As soon and for as long a control pulse is realized from one of these two control pulse sources, the OR gate 165 is in the conducting state, and permits an injection process to be carried out through the end stage selected by the signal generator 130 and the corresponding valve group. The injection process takes place during the duration of these control pulses. As shown in FIG. 8 for the instant of time r such an injection process can prevail beyond the end of an individual control pulse, when two control pulses and Z overlap only partially.

The second fuel injection arrangement of FIG. 9 differs principally from the first injection arrangement described above, through the condition that the acceleration enrichment fuel quantity is realized on the basis of the intermediate pulses Z as well as through normal pulses .1 generated synchronously with the rotations of the crankshaft of the engine. These normal pulses 1,, may be extended in duration over a widely varying factor. A multiplying stage 300 is provided here in place of the stage 170 behind the control multivibrator 150 in FIG. 7. This multiplying stage 300 includes an intermediate transistor 310 of NPN type, as well as two

transistors

301 and 302 of PNP type. A further transistor 303 also within the multiplying stage 300 is of the NPN type. The emitter of the transistor 301 is connected to the positive voltage line 90, through a resistor 304. One electrode of a storage capacitor 305 is connected to the collector of this transistor 301. The other electrode of the storage capacitor 305 is connected to the base of the transistor 303, as well as the collector of the transistor 302. The base of the transistor 302 is joined to ajunction or tap of a voltage divider consisting of resistors 306and 307. The emitter of the transistor 302, on the other hand, is joined to the positive voltage supply line 90, by way of the resistor 308. The emitter of the output transistor 303 of the multiplying stage 300, is connected to the negative voltage supply line 100, whereas the collector of this transistor 303 leads, by way of the resistor 309, to the positive voltage supply line 90. At the same time, this collector of the output transistor 303 isjoined to one input of an OR gate 165 which may be of the design derived from FIG. 7. In this regard, the transistor 16.3 may be thought to be connected with the collector of the transistor 303 through a coupling resistor designated as 166 in FIG. 7.

The intermediate transistor 310 is connected through its base to the collector of the transistor 152 associated with the control multivibrator 150. The collector of the intermediate transistor 310 leads to the positive voltage supply line 90, by way of a resistor 312. At the same time, the collector of the transistor 310 is also connected to an input of the OR'gate 165, through the resistor 311. This connection may be termed to be the base of the transistor 163. The second coupling resistance which leads to the transistor 163 belonging to the OR gate 165, as shown in FIG. 7, leads also to the collector of the transistor 251 in FIG. 9. This transistor 251 belongs to the monostable multivibrator 250 which supplies additional pulses Z.

The monostable multivibrator 250 is actuated in a manner similar to the injection arrangement of FIG. 7. Thus, the monostable multivibrator is actuated through the bistable multivibrator 230 and through intermediate differentiating elements 260. As a result of the opening motion of the throttle flap of the engine, a series of intermediate pulses Z are generated from the cross-stages by the

contact track

62 and 63 which are traversed by contact springs 40. These pulses Z are shown in FIG. 10 through six pulses in the waveform designated IV. In contrast to the arrangement of FIG. 7, different elements lie between the junction A of the monostable control multivibrator 250 of FIG. 9. Thus, connected to the junction A, is a capacitor 257 which serves as a timing elemerit, a resistor 255 associated with the transistor 252, and a diode 258 connected directly to the collector of this transistor 252. Connected also to the collector of the transistor 252 is a series circuit including the resistor 261, diode 262 and capacitor 263. The collector of the transistor 252 leads to the posi tive supply line through this series circuit combination.

The base of a PNP transistor 265 is connected to the junction of the diode 262 and capacitor 263. A resistor 264 is connected in parallel with the capacitor 263. This transistor 265 functions as an emitter follower through the connection of the resistor 266 between the emitter ofthis transistor and the posi tive voltage supply line 90. The detailed functional operation of the multiplying stage 300 in conjunction with the intermediate pulses Z delivered by the monostable multivibrator 250 may be described as follows:

The transistor 252 is turned on in the monostable multivibrator 250 for the duration of the intermediate pulse Z. During each one of these intermediate pulses, the capacitor 263 may become charged in the base circuit of the transistor 265. As a result of such charging, the voltage U across the capacitor 263 increases. The resistor 26] lying in the charging circuit is selected with low ohmic value compared to the resistor 264 lying in the discharge circuit of the storage capacitor 263, so that the voltage U achieves the maximum charging potential prevailing between the two resistors 267 and 268, after three intermediate pulses Z. The two resistors 267 and 260 belong to the voltage divider. The base of the transistor 265 follows the function or waveform of the capacitor voltage U,. A current i is applied to the collector of the transistor 265, which corresponds to the capacitor voltage. This current is applied through the emitter resistor 266. This current i is also applied additionally as charging current to the storage capacitor 305 within the multiplying stage 300.

For the purpose of understanding the function of the additional charging current i it is essential to consider next the functional operation of the multiplying stage 300 during stationary operation of the internal combustion engine. Assume, for example, that at the instant of time 1,, one of the

switches

101 and 102 of the signal generator 130, becomes closed through the action of the cam which operates the switch. In that case, the output transistor 152 of the control multivibrator 150 is transferred to the conducting state for the duration of the control pulse 1,. As a result, the intermediate transistor 310 becomes turned off, and the input transistor can deliver a practically constant charging current i, to the storage capacitor 305. The input transistor 1301 accomplishes such 1 constant charging current during the interval of the control pulses .I,, and through the voltage divider consisting of resistors 311 and 312. The voltage U across the capacitor 305 increases proportionally with time as shown to the left of the waveform II in FIG. 10. For the duration of these control pulses, the OR gate 165 may be maintained conducting, through the resistor 311. As soon as the control as the control pulse J, terminates at the instant of time 1 the intermediate transistor 310 returns to its original conducting state. As a result, the capacitor 305 has the potential of the negative voltage supply line 100 applied to it, through the base-collector path of the input transistor 301. Through the charge stored on the capacitor 305, the output transistor 303 becomes turned off and remains in this turned-off state until the instant of time 1 1. At that instant of time, the constant charging current delivered by the transistor 302 has equalized the charge and thereby allows the transistor 303 to return to its original conducting state. The OR gate 165 remains further conducting during the time interval 1 to corresponding to the cutoff interval of the output transistor 303. This is due to the condition that the transistor 163 of the OR gate 165 receives base current through the resistor 309. In the example described, the discharge current of the storage capacitor 305 is precisely as large as the charging current i, flowing through the input transistor 301. As a result, the duration of the normal pulses J,, for the injection process, is twice as large as the duration of control pulses J, realized from the control multivibrator 150.

A multiplying stage which is shown in FIG. 9 in simplified form, is independent of the operation of the present invention. It is of particular importance when only a portion of the control multivibrator takes into account varying operating conditions during the operation of the internal combustion engine. One such varying condition or parameter is, for example, the introduction of larger quantities of fuel for every cycle of the engine when the latter is not, as yet, warm. Such larger quantities of fuel are required when the engine is cold and is in the process of being heated. After the engine has been heated through operation, the amount of fuel can be reduced.

As may be seen from FIG. 10, the multiplication factor from the multiplying stage 300 is larger with increase in the charging current i,. From this possibility, use is made of extending multiplicatively the normal pulses 1,, for the injection arrangement of FIG. 9. For the next charging process of the storage capacitor 305 of the multiplying stage 300, at the instant of time t charging current i is realized additionally from the input transistor 301. At the same time, the transistor 265 sup plies further charging current i,. As a result of the three intermediate pulses Z generated through the throttle flap pulse generator, the charging current may have considerable magnitude. This is because the voltage U of the capacitor 263 may already have attained approximately its maximum value.

Through the combined effect of the two charging currents i, and an essentially rapid voltage rise appears across the capacitor 305 from the time instant I. When the discharge current remains unchanged, an extension of the injection process results. A larger amount of fuel is thereby injected which is represented in the diagram through crosshatching. The capacitor 263 has a discharge time constant of approximately l second, by being of the order of IO pf, and its voltage U decays thereby very slowly. This conditions results in an extension of the subsequent normalpulses, when the opening motion of the throttle flap is terminated after six intermediate pulses Z, in the illustrative example. A stepless transition of the normal pulse to greater length is thereby realized. Such greater pulse length is required for higher rotational speeds of the engine and after termination of the acceleration process due to increase in the air pressure within the intake manifold, the extension or lengthening of the normal pulses may be realized through the control multivibrator 150 alone, or in conjunction with further elements depending upon the rotational speed ofthe engine and not shown in the drawing.

FIG. 9 shows in broken lines a circuit arrangement which allows the intermediate pulses provided by the monostable multivibrator 250, to be shortened in duration when the number of these pulses increases. This circuit arrangement is shown within the monostable multivibrator 250. The function ofsuch shortening of the pulses is illustrated in the waveform VI in FIG. 10. This circuit arrangement for shortening the intermediate pulses, consists ofa resistor 254 of approximately 150 kohm connected in parallel with a capacitor 253 having a capacitance of the order of 2.2 pf. This capacitor becomes charged from the conducting transistor 252, similar to the capacitor 263 during the presence of the intermediate pulses Z. Within the interval between two successive intermediate pulses Z, the capacitor 257 within the feedback circuit of the monostable multivibrator 250, can become charged only to the potential U This capacitor 257 serves as a timing element. The potential U corresponds to the potential difference between the junction A and the base of the conducting input transistor 251.

The voltage U becomes smaller as shown in FIG. 10, and thereby the length or duration of the intermediate pulses Z becomes shorter, the greater the number of intermediate pulses generated. The intermediate pulses Z are formed through the unstable state of a monostable multivibrator 250. Such shortening of the duration of the pulses also occurs with increased frequency of the intermediate pulses as generated by the pulse generator and the bistable multivibrator 230.

In the injection arrangement of FIG. 9, the individual end stages in the form of AND gates and 125 determine cooperatively with the bistable multivibrator 130, which one of the two valve groups 110 and is to made effective through the intermediate pulses Z or Z.

For specific types of internal combustion engines, it may be of advantage to apply alternatingly to the valve groups only the normal pulses 1,, generated synchronously with the crankshaft rotation. At the same time, the intermediate pulses Z and Z are used for auxiliary injection processes simultaneously at the two valve groups. In this regard, the injection arrangement shown in FIG. 9 can be easily modified so that the two interconnected inputs of the two AND gates 115 and are directly coupled to the output of the multiplying stage 300. Instead of the OR gate 165, one of two OR gates is inserted between each AND gate and its end stage. These two OR gates are connected with one of their two inputs, to the collector of the transistor 251, whereas the other input is connected to the output ofthe AND gate 115 or the AND gate 125.

From the diagram of FIG. 10 it may be seen that the first intermediate pulse appearing at the time instant t and the fourth intermediate pulse which appears at the time instant 1 fall within the normal pulse J,,. These pulses, thereby, become lost from the viewpoint of acceleration enrichment, notwithstanding their contribution to the formation of the capacitor voltage U,,.

In the injection arrangement of FIG. 11, means is provided that such intermediate pulses which are completely overlapped from the normal pulses J,,, are first introduced into a storage and become then attached to the end of the overlapping normal pulse. For this purpose, one of the two inputs of the OR gate is connected to the collector of the output transistor 303 of the multiplying stage 300. The second input is connected, as shown in FIG. 9, to the intermediate transistor 310, by way of the resistor 311. Instead of the multivibrator 250 used in the injection arrangement of FIGS. 7 and 9, a switching element is connected to the two differentiating circuits 240, through both of the

diodes

248 and 219. This switching element or circuit portion also functions as an electronic storage or electronic logical element in conjunction with the two AND

gates

115 and 125, and provides moreover, the function of the bistable multivibrator 250.

In particular, this circuit contains an NPN transistor 271 and a second NPN transistor 272 with its base connected to the collector of the transistor 271. Both of the emitters of these two transistors are connected to the negative voltage supply line 100. The collectors of the two transistors lead, respectively, to the positive supply line 90, by way of the resistors 273 and 274. A resistor 270 is, furthermore, connected between the base of the transistor 271 and the negative voltage supply line 100. Oppositely directed diodes 275 and 2 59 are connected, at the same time, in series with the base circuit of the transistor 271. The diode 248 directed identical to that of diode 249 is joined to the junction of the

diodes

275 and 249. The cathodes of two additional diodes 276 and 278 are also joined to thejunction between the

diodes

249 and 275. A resistor 277 is connected between the anode of the diode 278 and the collector of a PNP transistor 281. A resistor 279 is connected in series with the diode 276 and is, at the same time, connected to the collector of the transistor 272. The col lector of the transistor 272 is joined to a feedback coupling capacitor 282 which is connected between this collector of the transistor 272 and the junction D between the diode 278 and the resistor 277. Through this design which includes the feedback capacitor 282, the transistor 272 functions together with the transistor 271 in the form of a monostable multivibrator circuit similar tothe monostable multivibrator 250 through which intermediate pulses Z are produced as described in the preceding injection arrangement, by way of the throttle flap pulse generator, the bistable multivibrator 230 and the dif ferentiating elements 240.

In contrast to the first one of the two injection arrangements shown in FIG. 7 and FIG. 9, the output of the OR gate 165 is not directly coupled to the two AND

gates

115 and 125. The first input of the two AND

gates

115 and 125 each leads to the signal generator 130, by way of the connecting

path

113 and 128, respectively. The other inputs of the AND

gates

115 and 125 are decoupled from each other through the respective series circuits consisting of the diode 283 and resistor 28d, and the diode 285 connected in series with the resistor 2116. The two resistors 284 and 286 are joined at a common connection, and the output of the OR gate 165 is also joined to this common connection, through the resistor 287. The anode of a diode 288, furthermore, is also connected to this junction G of the resistors 284, 286 and 287. The cathode of the diode 288 is connected to the collector of the transistor 272. The circuit also includes a further transistor 290 of the PNP type. The emitter of this transistor 290 is directly connected to the negative voltage supply line 100, whereas the base of the transistor 290 leads to the output of the OR gate 165, by way of the resistor 291. Thus, the output of the OR gate 165 feeds to the resistors 287 and 291. Connected to the collector of the transistor 290, are two resistors 292 and 293. The resistor 292 leads directly to the positive voltage supply line 90, whereas the resistor 293 leads to the base of the transistor 281 which is PNP transistor. The circuit constructed of the elements 270 to 293 operates in accordance with the waveform diagram of FIG. 2, in the following manner:

The pulse generator 130 transmits normal pulses synchronously with the rotation of the crankshaft of the internal combustion engine. These normal pulses appear at the output C ofthe OR gate 165, and this output signal of the OR gate will be designated at negative potential in the description below. The output signal of the OR gate 165 is only a few tenths of a volt above the potential of the negative voltage supply line 100. Each of the two AND

gates

115 and 125 can transfer its respective end stage to the conducting state only when both of its inputs are at negative potential. Accordingly, an injection process can take place only when the junction G is at negative potential. This is, however, also the case with the aforementioned normal pulses, for as long as the transistor 272 is in the conducting state. The transistor 290 which serves to drive the PNP transistor 231, is maintained in the conducting state over the resistor 291, provided that no signal appears at the output C of the OR gate 165. Base current for the transistor 2&1 can then flow through the resistor 293, so that the transistor 281 may become conducting. In this turned-on state of the transistor 281, base current is applied to the transistor 271 through the resistor 277 and the diode 278. The transistor 271 thereby conducts during the intervals between two normal pulses, whereas the transistor 272 which is directly coupled to the transistor 271, is turned off. As soon as a negative potential appears at the output C, at the beginning of a normal pulse, the transistor 2911 is turned off and the transistor 281 is consequently also turned off. As a result, no current can flow over the resistor 277, for the transistor 271. When the switching stage consisting of transistors 271, 272 and 281 has not, as yet, been actuated by the transfer in states of the bistable multivibrator 230, at for example the instant is in FIG. 12, then this unactuated switching stage remains in its quiescent state. In this quiescent state, the transistor 272 is turned off, whereas the transistor 27] is turned on as a result of the base current flowing through the resistor 279, the diode 276 and the diode 275.

If, however, in accordance with the uppermost curve in FIG. 12 and at the instant of time 1 the monostablc multivibrator 2311 becomes actuated as a result of the contact finger 40 of the pulse generator shown in FIGS. 4 to 6, rides upon the next cross-stage 66 or 67, a turning-off signal for the transistor 271 will appear through the differentiating elements 240. As a result, the transistor 272 can transfer to its connecting state. As shown in the next to the last curve in FIG. 12, the junction G acquires negative potential for the time interval of the now following intermediate pulses Z. For as long as no normal pulse appears, as illustrated for the time interval between t and I in FIG. 12, the transistor 28! is in the conducting state. Accordingly, the capacitor 282 which functions as the timing element for the intermediate pulses, may become charged through the resistor 277. The capacitor 282 may acquire such charge until the transistor 271 becomes again conducting. A voltage function is then realized at the junction D, as illustrated in the third diagram over and beneath the time axis t for both of the first intermediate pulses] which appear at the time instant 1;, and

A third emission of an intermediate pulse results at the time instant t At that time, however, the normal pulse emitted at instant 1,, is in effect. A prevailing normal pulse has the characteristics, in accordance with the above-described features, that the

transistor

290 and 281 become cut off. At the instant of time i the transistor 271 becomes turned off through the signal transmitted from the differentiated stage 240, and the transistor 272 is consequently turned on. The resulting step voltage appearing at the transistor 272 is then transmitted to the base of the transistor 271. Charging of the capacitor 282 can then first take place, when the transistor 281 is turned on. This corresponds to the time after the instant I during which the normal pulses from the OR gate and synchronized with the engine speed, are terminated. Thejunction D has, thereby, a rising potential after the time instant i since charging of the capacitor 282 is now possible through the resistor 277 and the conducting transistor 281. After the interval of the intermediate pulse, designated as 1,, the transistor 272 returns to its stable turned-off state. The intermediate pulse initiated at the time instant therefore, does not become lost for purposes of fuel enrichment. Instead, this pulse becomes attached to the end of the normal pulses generated synchronously with the crankshaft rotation of the engine.

it will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in a fuel injection arrangement, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

What we claim as new and desire to be protected by Letters Pat. is:

1. An electrically controlled fuel injection arrangement for an internal combustion engine comprising, in combination, at least one electromagnetically controlled injection valve for injecting fuel into the engine; energizing means connected to said valve for energizing electrically said injection valve; control multivibrator means having stable and unstable states and being connected to said energizing means; first pulse-emitting means connected to said control multivibrator means and emitting speed-dependent pulses proportional to the speed of said engine, varying in frequency upon speed variations of said engine, said pulses triggering said multivibrator means to said unstable state for opening said valve, said multivibrator means returning to said stable state after a predetermined and variable time interval; and second pulse-emitting means triggered by means actuated primarily during increased demand for power output from said engine, and emitting at least one auxiliary pulse between two successive speed-dependent pulses from said first pulse-emitting means, said auxiliary pulse being applied to said injection valve for increasing the quantity of fuel injected during increased demand for power output from the engine.

2. The fuel injection arrangement as defined in claim I, wherein said means actuated primarily during increased demand for power output from the engine is the throttle of the engine, said second pulse-emitting means delivering a train of auxiliary pulses during opening motion of said throttle.

3. The fuel injection arrangement as defined in claim 2, wherein said second pulse-emitting means delivers at least five auxiliary pulses distributed over the total opening of said throttle.

4. The fuel injection arrangement as defined in claim 1, wherein said means actuated primarily during increased demand for power output from the engine is the throttle of the engine, and said second pulse-emitting means includes switch contact means; and switch element means rotatable by said throttle and cooperating with said switch contact means so that the latter is actuated only during opening motion of said throttle.

5. The fuel injection arrangement as defined in claim 4, wherein said second pulse-emitting means comprises further a disc member coupled to the shaft of said throttle and having a plurality of teeth distributed along the rim of said disc; and stationary contact members cooperating with said disc and being in contact with said teeth during opening motion of said throttle.

6. The fuel injection arrangement as defined in claim 4, wherein said second pulse-emitting means comprises further two contact tracks isolated from each other electrically and having radial cross-contact portions directed opposite to the contact portions of the other track; and contact finger means movable with said throttle and contacting said radial cross portions.

7. The fuel injection arrangement as defined in claim 6 including a third contact track and a second contact finger for maintaining continuous contact with said third contact track during opening motion of said throttle.

8. The fuel injection arrangement as defined in claim 7 including insulating plate means for carrying said contact finger means and mounted upon the shaft of said throttle.

9. The fuel injection arrangement as defined in claim 8 including base plate means for carrying said contact tracks; and braking means for holding said base plate means and said insulating plate means.

10. The fuel injection arrangement as defined in claim 9 including a drag switch mounted on said insulating plate means; and actuating means mounted on the shaft of said throttle and actuating said drag switch during opening motion of said throttle.

11. The fuel injection arrangement as defined in claim 10 including contact springs extending from said contact fingers and located in the path of said actuating means, each of said contact springs having contact portions at the end of said spring.

12. The fuel injection arrangement as defined in claim 11 including auxiliary contact springs secured to said base plate means and actuated by said actuating means during closing motion of said throttle.

13. The fuel injection arrangement as defined in claim 12, including an OR gate means connected to said energizing means and having one input connected to the output of said control multivibrator means; and wherein said second pulseemitting means includes bistable multivibrator means triggered back and forth between its two states during opening movement of said throttle.

14. The fuel injection arrangement as defined in claim 13, wherein said second pulse-emitting means includes monostable multivibrator means for determining the duration of said auxiliary pulses, and differentiating means connected between said bistable multivibrator means and said monostablc multivibrator means.

15. The fuel injection arrangement as defined in claim 14, wherein said monostable multivibrator means includes an input transistor, said input transistor being conductive when said monostable multivibrator means is quiescent, an output transistor coupled to said input transistor, coupling capacitor means connected between the collector of said output transistor and the base of said input transistor, and a diode connected between the base of said input transistor and said coupling capacitor, said auxiliary pulses being taken from the collector of said input transistor.

16. The fuel injection arrangement as defined in claim 15, including regulating voltage-generating means for generating a voltage varying as a function of the number of said auxiliary pulses and influencing the duration of the latter, the duration of said auxiliary pulses decreasing with increasing number of said auxiliary pulses.

17. The fuel injection arrangement as defined in claim 16, wherein said monostable multivibrator means includes an input transistor and an output transistor, a diode connected to the collector of said output transistor, a first resistor connected in series with said diode and having a resistance value substantially within the range of 5 to 50 kohms, a second resistor connected in series with said first resistor and having a resistance value substantially within the range of kohms to 300 kohms, storage capacitor means connected in parallel with said second resistor and having a capacitance of at least 1 ],L., and feedback coupling capacitor means connected between the base of said input transistor and the junction of said first resistor and said diode.

18. The fuel injection arrangement as defined in claim 17, including multiplying means connected to said control multivibrator means and applying a lengthening factor to said pulses from said control multivibrator means, said lengthening factor being a function of the number of said auxiliary pulses and being made variable as a function of a charging current.

19. The fuel injection arrangement as defined in claim 18, including emitter-follower transistor means for providing said charging current; a base capacitor connected to the base of said emitter-follower means; a resistor connected in parallel with said base capacitor, said base capacitor being charged for every one of said auxiliary pulses, the discharge time constant of said capacitor being substantially at least l0 times larger than the charging time constant.

20. The fuel injection arrangement as defined in claim 19, including electronic storage means for storing said auxiliary pulses, and means for adding to said speed dependent pulses those auxiliary pulses that are overlapped by said speed-dependent pulses.

speed-dependent pulse; feedback coupling capacitor means connected between the collector of said output transistor and the base of said input transistor; a diode connected between said feedback coupling capacitor and the base of said input transistor; and an auxiliary feedback circuit connected between the collector of said output transistor and the base of said input transistor, said auxiliary feedback circuit comprising a resistor and diode connected in series.

Claims

1. An electrically controlled fuel injection arrangement for an internal combustion engine comprising, in combination, at least one electromagnetically controlled injection valve for injecting fuel into the engine; energizing means connected to said valve for energizing electrically said injection valve; control multivibrator means having stable and unstable states and being connected to said energizing means; first pulse-emitting means connected to said control multivibrator means and emitting speeddependent pulses proportional to the speed of said engine, varying in frequency upon speed variations of said engine, said pUlses triggering said multivibrator means to said unstable state for opening said valve, said multivibrator means returning to said stable state after a predetermined and variable time interval; and second pulse-emitting means triggered by means actuated primarily during increased demand for power output from said engine, and emitting at least one auxiliary pulse between two successive speed-dependent pulses from said first pulseemitting means, said auxiliary pulse being applied to said injection valve for increasing the quantity of fuel injected during increased demand for power output from the engine.

2. The fuel injection arrangement as defined in claim 1, wherein said means actuated primarily during increased demand for power output from the engine is the throttle of the engine, said second pulse-emitting means delivering a train of auxiliary pulses during opening motion of said throttle.

13. The fuel injection arrangement as defined in claim 12, including an OR gate means connected to said energizing means and having one input connected to the output of said control multivibrator means; and wherein said second pulse-emitting means includes bistable multivibrator means triggered back and forth between its two states during opening movement of said throttle.

14. The fuel injection arrangement as defiNed in claim 13, wherein said second pulse-emitting means includes monostable multivibrator means for determining the duration of said auxiliary pulses, and differentiating means connected between said bistable multivibrator means and said monostable multivibrator means.

17. The fuel injection arrangement as defined in claim 16, wherein said monostable multivibrator means includes an input transistor and an output transistor, a diode connected to the collector of said output transistor, a first resistor connected in series with said diode and having a resistance value substantially within the range of 5 to 50 kohms, a second resistor connected in series with said first resistor and having a resistance value substantially within the range of 100 kohms to 300 kohms, storage capacitor means connected in parallel with said second resistor and having a capacitance of at least 1 Mu ., and feedback coupling capacitor means connected between the base of said input transistor and the junction of said first resistor and said diode.

19. The fuel injection arrangement as defined in claim 18, including emitter-follower transistor means for providing said charging current; a base capacitor connected to the base of said emitter-follower means; a resistor connected in parallel with said base capacitor, said base capacitor being charged for every one of said auxiliary pulses, the discharge time constant of said capacitor being substantially at least 10 times larger than the charging time constant.

21. The fuel injection arrangement as defined in claim 20, wherein said second pulse-emitting means includes monostable multivibrator means controlled by said bistable multivibrator means for generating said auxiliary pulses and having an input transistor and an output transistor, said auxiliary pulses being delivered by said output transistor; a base current transistor for supplying current to the base of the input transistor, said base current transistor being turned off during emission of a speed-dependent pulse by said first pulse-emitting means and being turned on upon termination of said speed-dependent pulse; feedback coupling capacitor means connected between the collector of said output transistor and the base of said input transistor; a diode connected between said feedback coupling capacitor and the base of said input transistor; and an auxiliary feedback circuit connected between the collector of said output transistor and thE base of said input transistor, said auxiliary feedback circuit comprising a resistor and diode connected in series.