DE2300176A1 - CIRCUIT FOR FUEL ENRICHMENT AT FULL LOAD - Google Patents

Description

Pcfonfanv-ilt 2300178

K α r i / ■ · ,. r υ s e

D-8023 !; Z; iz '.'. M - PuHach
Vienna-: fs! R.2j.Mdiil.7930570,793i782

v.I / st a - 4363-A Manche η -Pul lach., Jan. 2, 1973

: TH *! BENDIX COHPORATICH, Executive Offices, Bendix Center, j Southfield, Michigan 48Ο75, Michigan, USA i

Circuit for fuel enrichment at full load

The invention relates to the field of electronic fuel Control systems for internal combustion engines and, in particular, that section of the aforementioned field that covers the Provide precisely measured amounts of fuel during Relates to transitional operating conditions of an internal combustion engine. In particular, the invention relates to that section of the aforementioned field which is responsible for this is, increased amounts of fuel for consumption by the engine to be provided when the machine is working under full load conditions.

The term "full load" used herein means the state of operation of the machine in which there is an intake pipe pressure is generated which is substantially within ten percent of the ambient atmospheric pressure igt. According to the prior art, it is known that a state corresponding to a full load by mechanical or electrical scanning of the "division of the air control throttle -i.! plate can be determined, and if such a full load-indicating Position is scanned, an increased tight or increased amounts of fuel to the engine can be abfifVnon will. Such an arrangement, however, leads to disparity Inaccuracy ^ n and difficulties with itself. First • ■ 5th Tina mechanically scanned or mechanically able

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Brable electrical contacts are subject to setting errors and often have to be recalibrated to ensure accuracy. Second, in a simple and economical form, such a facility only allows a digital one Determining that the full load enrichment requirement is in effect is. The planned fuel increases for full load enrichment purposes are essentially uniform and are therefore not in line with the actual requirements the machine. In addition, systems that rely on mechanical devices through which signaling should be provided, a relatively short service life, u. betw. in comparison with the desire of automobile manufacturers, after which a service life of 50 to 100,000 miles for the vehicle and the machine systems is sought. So it is It is an object of the present invention to provide means for providing a full load accumulation amount or amounts to create fuel that does not have mechanical contacts to signal the need for full-load enrichment are based. ' It is also an object of the invention to provide a circuit capable of changing degrees to recognize full load enrichment requirements in order to air ^ icherungsmeηgeη of fuel to be provided in sinklang with may fluctuate according to need. It is also an object of the invention to provide a device in a purely electronic circuit form for detecting and providing full load enrichment fuel Provide quantities that are also in line with the goal of the automobile manufacturer with regard to a service life stands from 5 ° to 100,000 miles.

The present invention provides a circuit "that recognizes whether the machine is working in a state "in which a full load enrichment is required or not j and then to change the fuel to drove -3 expensive pulses, -3 ο that those Impulses in Sinklang are prolonged with the degree to which the operation of the machine in the area the full load enrichment requirement has extended. According to the invention use is made of the fact that the

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Full load enrichment requirement by the Maeehinen intake manifold pressure or the engine intake manifold pressures can be identified which exceed a predetermined 7 / i-trt, which can be, for example, atmospheric pressure minus 75 torr. According to one embodiment of the invention the system receives as an input signal that Signal indicative of the current engine intake manifold pressure and receives a reference signal for comparison purposes. If the circuit detects that the manifold pressure has increased above the reference value, it will activated a switching circuit to excite a current sump (sink) in order to reduce a tfert of a current, which then charges a time control capacity. In this way the sequence of increases in voltage across the timing capacitance becomes reduced. In this way, a machine that is already slightly operating in the full-load enrichment area is already receiving a small additional amount of fuel for enrichment purposes, while a machine already working well within the zone in which full load enrichment fuel quantities are required, a greatly increased amount of fuel receives.

According to a preferred embodiment of the invention, the generated waveform has a full load enrichment section on, and the changes in the visual wave value as a function of the intake manifold pressure or the intake manifold pressures, which indicate the full load are arranged so that they are at values above a minimum value of the Full load enrichment section. Oa according to the invention the previously defined task is solved with the help of a fully electronic circuit that uses electronic signals, that exist within an operational electronic fuel control system will also be the desired service life achieved in the subject matter of the invention.

Further advantages and details of the invention result

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.from the description of exemplary embodiments that now follows referring to the drawing. It shows

Fig. 1 in schematic form an electronic fuel off st your syst em for an internal combustion engine, in which the subject matter of the present invention can be useful;

Fig. 2 is a block diagram of an embodiment of a electronic control unit for use in the system of Figure 1;

FIG. 3 shows an expanded block diagram of a section of the block diagram of FIG. 2 according to an embodiment according to the invention;

Figure 4 is an expanded block diagram of a portion the block diagram of Figure 2 according to an alternative embodiment of the invention;

Fig. 5 shows an electronic circuit according to the invention for use in the block diagrams of FIGS. 3 and 4;

6 shows an electronic circuit according to FIGS. 2, 3 and 4, in which the subject matter of the invention can be useful; and

Fig. 7 is a graphical representation of a composite Voltage waveform, a trigger pulse and a long pulse for illustration the advantages of the article according to the invention.

Fig. 1 shows in schematic form an electronic fuel control system. The system consists of a main computer device or electronic control unit 1C,

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an intake manifold pressure sensor 12, a temperature sensor. 14, an input timing device 16, and various samplers, designated 18. The intake manifold pressure sensor 12 and the associated further scanner 18 are arranged on the throttle body 20, but it is emphasized that other positions are also possible. The output of the computer device 10 is an electromagnetic Injection valve part 22 coupled, which is located in the inlet suction pipe 24 and is arranged to fuel from the tank 26 via the pump 28 and suitable fuel lines 3 ^ for delivery to a combustion cylinder 32 of any embodiment of an internal combustion engine that is not further shown to be provided, although the injection valve part 22 is shown emitting a fuel spray into an open inlet valve 34, it should be emphasized that that this representation is chosen as an example only, and that other dispensing arrangements are known and for Can apply. It is further well known in the art that computing device 10 is an injector device can control, which consists of one or more injection valve parts 22, which are so arranged

j, or which is arranged in such a way that it can be operated individually

j can, or that they are in groups of different numbers in ι

a ^ olge, but also at the same time, can be operated.

The computer device is energized by a battery 36 which powers the vehicle battery and / or the battery charging system, but can also be a separate battery.

The block diagram shown in "Pig. 2 illustrates the Computer device 10 of "FIG. 1" in a non-specific manner Form used in a fuel system in which two-group injection is provided. In ^ i.s :. 2, a switch device 38 is shown which provides AC output signals can generate and receive as an input variable a signal or signals that are characteristic of the Crank angle of the machine as from T? Ig scanner 16. 1 determined, ainü. In the mechanical embodiment can

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230 Oil 76

the scanner 16 order from a single-lobed cam that is driven by the machine and alternately opens and closes a pair of contacts. Since this arrangement interfering signals can generate, such as by contact bouncing, the switch device 38 is assumed here as a flip-flop and as the "flip-flop" is known to be an output variable with a substantially constant value at an output terminal and an output of the value zero at the other output connection as a function of a trigger signal, which is only due to an input voltage peak needs to exist, as is illustrated by lines 1 and 2 in Fig. 2, but can also take longer, and because a flip-flop can be made immediately insensitive to other types of signals. Signals at the Fichttrigger input received, of course, have no influence on the flip-flop «. The outputs 40 and 42 lead to Entrance of the unit 50 and also lead to the entrances of a pair of AND gates, the output 40 being connected to the one input of the AND gate 46 and the output 42 is connected to the one input of the AND gate 43. The unit 50 receives as a control input a signal from pressure scanner 12 indicating a machine operating condition or indicates an engine operating condition and therefore indicates the engine's fuel requirement. The scanner 12 is here completely connected to a suction pipe or command line 52 shown coupled. The actual position of the scanner 12 depends on the dynamic properties of the Inlet suction pipe and the Droesel body. The unit 50 can also receive signals from temperature scanner 14, and it should be noted that other scanner inputs, though not shown, can be used. For the sake of simplicity, however, the additional control inputs have been added not illustrated .. The output of unit 50 is connected to a second input from each AND gate 4b and 48 connected. The output of the: AND gate 46 is with the Amplifier 56 connected, in turn, a control current for the first injection group. The output of the

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AND gate 48 is connected to amplifier 58, which provides a control current for the second injection group.

As will be shown in detail in the following, an output signal from the flip-71op 38 occurs at one output connection, and the other output connection is excluded. This signal then appears at an input of only one AND gate of only one amplifier. This signal selectively designates an injector or injection group for an upcoming injection. As an example, it is assumed that the output signal of the flip-flop 38 appears at the output terminal 40, so that the signal also appears at an input of the AND gate 46. The signal at the output 40 of the flip-flop 33 also appears at an input of the unit 50, and if one assumes that the flip-flop 38 has just changed its state, a brief signal is sent to the unit 50. The unit 50 generates one Output variable over the course of a predeterminable period of time. This time is determined by the values of the scanner input variables that reach the unit 5 ^r . During this period of time, the output of unit 50 provides a nominal force output. This signal is applied to one input of each of AND gates 46 and 48. Due to the nature of AND gates, an output signal is only generated when an input signal is applied to each and all of the inputs. This then results in the AND gate 46 generating an output which is amplified by the amplifier 56 to open the first injection group, since this group receives an injection selection command directly from flip-flop 38 and an injection control command from unit 5 < At the end of the time delay period, unit 50 generates a ^{zero v} / ert signal so that the injection control command output is removed from the input of AND gate 46 and the output of AND gate 46 drops to zero , thereby allowing the first group of injectors to close. During the period of time that the first group of injectors is open, a metered amount of fuel

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. injected under pressure by the first injection group. In Dependence on certain selected electronic devices Suitable amplifiers and / or inverter stages can be used to generate the achievable and derivable signals the desired or required circuit response properties adapt.

In FIG. 3, the unit 50 of FIG. 2 is illustrated in the form of a plurality of functional blocks. The unit 50 consists of a waveshaper generator 60, a variable reference device 62 and the full load enrichment device 64 according to the present invention. Waveform generator 60 receives the trigger information from flip-flop 38 and generates a voltage waveform in response thereto, as illustrated by waveform 90 in FIG. The electronic circuit diagram of FIG. 6 shows one way of generating the desired waveform and will be explained in more detail below.

The waveform voltage becomes the variable reference device 62 and also to the full-load enrichment device 64, and between them via parallel circuit paths. The variable reference means 62 receives a signal from the pressure scanner 12 to provide a switch value. An electronic realization of this unity is also in Fig. 6 shown. It should be emphasized that the pressure signal input which the variable reference value means 62 receives, can be transmitted directly to the scanner 12 or processed in a suitable manner can be used to establish a desired relationship between pressure fluctuations conditions and threshold value fluctuations.

The full load enricher 64 receives on the input port 66 a variable signal which terminal corresponds to the output terminal 66 of FIG. 6 and which is shown in FIG in this case is the waveform generated. This facility

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2 30 of 76

compares the waveform with a reference value. The reference value can be determined by, analytical or empirical test methods for "certain machine shapes or constructions are selected or" determined. The full load enrichment facility 64 may be arranged so that it "provides an output signal at 68, which is indicative of whether the waveform stress generated is larger or smaller than the thawed reference quantity, here denoted by R, or not. By a suitable circuit design, as described in Pig. 5, the full load enrichment device 64 or for this purpose the waveform generator 60 is so arranged that the waveform is changed as it passes through the reference value. This changed waveform would then get to the facility building the threshold to perform the full load enrichment pulse lengthening according to of the present invention to achieve "or to realize.

FIG. 4 now shows an alternative arrangement for the signal processing in contrast to the embodiment illustrated in FIG. 3. Since essentially the same units are illustrated in FIG. 4 that were explained with reference to FIG. 3, the same reference numerals have been chosen for corresponding units. ⁷⁷ Ig. 4 is different from?! £ ;. 3 primarily with regard to the consequences of information processing. The full load enrichment device 64 receives the pressure signal generated by the scanner 12 as a variable input variable 66. This may be the same signal as the signal received by the variable reference device 62 (i.e., either as generated or as processed), or the device may receive its signal under different processing to provide a different jerk response characteristic than that provided for the variable reference value means 32. In the embodiment according to FIG. 3, the variable signal 66 is compared with a reference signal R in order to produce an output signal at 68 for influencing the operation of the

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waveform generating device 60 to generate in the manner previously described.

Fig. 5 now shows a practical embodiment of an electronic Circuit of the full load enrichment device 64. The enrichment device 64 contains a bistable comparison circuit 70 with a pair of transistors 72, 74, a switch device in the form of a transistor 76 and a circuit 78 which can be actuated as a function of the switch device 76 in order to control the flow by the generator 60 of Figs. 3 and 4 to change the waveform generated. The circuit 78 is illustrated here as a current sink, with a control transistor 80 and a current-consuming resistor I 82.

The R reference signal is obtained through a voltage divider network, consisting of resistors 84, 86, which are the voltage source Connect B + to the common earth or ground, creates. The voltage source B + can, for example, be the battery 36 of the vehicle or can be from the shared battery charging system exist or can be provided by a separate voltage source. The connection point between resistors 84 and 86 are coupled to the base or control terminal of transistor 74, and that connection is labeled R so that it corresponds to the similarly labeled signal input of FIGS. This reference signal can be formed by a fixed value, but it is preferable to take measures for fluctuations in the ambient pressure meet, and between ' by compensation in the form of known ambient pressure compensation techniques. It can, for example, ad, er resistors 84, 86 a pressure-sensitive potentiometer section that is responsive to the ambient pressure. The collector of transistor 74 is connected to the voltage source B +, and the emitter of transistor 74 is coupled to the emitter of transistor 72. Both emitters are connected to resistor 88, which leads to "ground" or earth. The base of transistor 72 receives in a suitable manner

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Mode the variable input signal at input 66. This arrangement is commonly referred to as an emitter-coupled pair, and there is one, and only one, of the transistors 72, 74 conductive at any point in time. That transistor, which is in the shown arrangement in the conductive State, where NPN transistors are used, is the transistor whose base or control connection receives the more positive voltage signal. If the When transistor 72 becomes conductive, the otromfluss through the collector causes a current to flow through the Bmitter-base junction of transistor 76 via holder device, and the circuit 73 is switched on or switched to an active operating phase.

Pig. Figure 6 illustrates electronic circuitry to meet the puncture requirements of blocks 60 and 62 in Pig's block diagrams. 3 and 4 to satisfy. The waveform generating circuit 6 ^r consists of a pair of current sources 601, 602 which are alternately applied to a pair of capacitances 603, 604 via a switch network 6C5 which receives the trigger signals 40, 42. The sequence or speed with which the capacitances 603, 604 are charged and discharged is controlled by the network 606, which also receives the trigger signals 40, 42. The variable reference means 62 takes a sample of the highest value of the voltages appearing across the capacitors 603, 604 and compares this value with the value established by the pressure sensor signal as previously described.

The current source 601 consists of the transistor 101, whose Base is connected to the connection point of a pair of voltage-dividing resistors 110, 111 ", and its Emitter is connected to resistor 112. The resistances 111 and 112 are connected to a potential source identified as B + is denoted, and the resistor 110 leads to measure or earth. The power source 602 is similarly composed

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• a transistor 102 whose base is connected to the connection point the voltage divider resistors 114-115 is connected, and the emitter of which is connected to resistor 113, which is also connected to the B - + source. This arrangement can build up a known value of a constant current flow in the collectors of the transistors 101, 102, respectively. The collector of the transistor 101 leads to a parallel connection or connection of collectors of a transistor pair 131, 132. Similarly, the collector of transistor 102 is connected in parallel to the collectors of a transistor pair 133 »134. The basic connections of the Transistors 131 and 134 are connected together via resistors 141, 142, while the base connections of the transistors 132, 133 are connected together via resistors 143 »144 are. The connection points between the resistors I4I, receive the trigger signals at 40, while the connection point between resistors 143 and 144 receive the trigger signals at 42 receives. The emitters of transistors 131 and 133 are connected to capacitance 603, while the emitters of transistors 132 and 134 are connected to capacitance 604 are. This circuit can then flow a current from the current source 601 through the transistor 131 to the capacitance 603 and provide a current from source 602 through transistor 134 to capacitance 604 whenever a high one The voltage signal is present on line 40 and a low voltage signal is present on line 42. Whenever there is a low voltage signal on line 40 and a high voltage signal on line 42 is, the current from the source 601 flows through the transistor 132 into the capacitance 604, while the current flows out der current source 602 through transistor 133 into capacitance 6O3 flows. The full load enrichment facility 64 provides a power sump to selectively draw power from the network subtract, which supplies the current to the capacitors 6O3, 604. This way the momentary tension can be over the capacitances 6O3, 604 are controlled in a preprogrammed manner in order to thereby the on the circuit line 66

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affect the tension that appears. With. Help the diodes 161, 162, which are directly connected to the capacitors 603, 604 the voltage appearing on circuit line 66 represents a value indicative of the highest of the voltage drops across the capacities 6O3, 6O4 is,

The network 606 consists of a first, a second, a third and a fourth control transistor corresponding to the numbers 135, 136, 137 and I38, a plurality of voltage value-building Resistor pairs 139 »HO and a multitude of voltage value-building diodes 145 to 150. A reset device 151 and other voltage value-building devices Diodes 152, 153 are also shown. A change in the state of the plip-flop 38, as in Pig. 2 illustrates has an inversion of the high-low signal relationship resulting from appearing on trigger lines 40, 42, and the appearance of a high signal on a line, for example line 40, results in the generation of a reset pulse from the reset device 151, which may be designed to generate a signal of relatively high value will. The reset device 151 can, for example, from consist of a monostable multivibrator or other circuit designed and arranged to a signal with a high voltage value for a certain period of time after receiving a trigger signal with a large Value generated. The presence of these high voltage signals on circuit line 40 and at the output of the reset device 151 causes the connection point 154 is at a relatively high voltage level, and that the transistor 138 becomes conductive via the diode device 147. This will turn causes transistor 137, the emitter of which is connected to capacitance 603, to become conductive, so that the voltage then appearing across the capacitance 603 is caused by a current flowing through the conductive transistors 137, 138 is broken down by mass. This

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Voltage reduction continues until the voltage appearing across capacitance 603 reaches a low value which is determined by the number of PN junctions between capacitance 603 and ground or ground. During this time interval, the current flow from the current source 601 through the transistor 131 is reduced to a level which characterizes an excessive voltage across the capacitance 603. After the end of the reset pulse from the reset device 151, the voltage at connection point 154 drops, and because of the large number of diodes in the diode device 147 this voltage is not sufficient to keep the transistor 138 in the conductive state. As a result, the transistor 138 and the transistor 137 are switched off, whereby the voltage reduction of the capacitance 603 ends w ^: rd, and the current flow from the current source 601 increases the voltage value across the capacitance 603 again. 7, the time interval of the reset pulse 151 corresponds to the initial charging interval AB on the curve 90, while the time interval BC represents the period during which the capacitance 603 is charged by the current source 601. The one represented by the CD line of curve 90 of Pig. The value shown in 7 represents a value when the charge on the capacitance 6O3 is sufficiently large relative to the voltage value which is built up by the action of the voltage divider from the resistors ItO, 111, so that the base-collector junction of the transistor 101 is reversed or vice versa is biased and the transistor closes. The operation of the network 60S in terms of receiving a signal with. The high value on trigger line 42 is essentially the same as that previously described, due to the fact that network 606 consists of two substantially identical halves, one of which has been described in detail. By a suitable selection of the resistance values in connection with the maintenance of a relatively small capacitance value of the capacitance 603 it can be achieved that the discharge of the capacitance 603 to a value which is indicated by the AB section of the curve 90 in Pig. 7, on a very short time scale relative to FIG

Duration of a trigger pulse can take place.

The variable reference means 62 receives a signal indicative of the manifold pressure at I70, and this signal is applied to the base of transistor 172. The base of transistor 171 receives the signal from circuit line 66. Since the emitters of transistors 171, 172 are coupled together, the one of these transistors is in the conductive state, which depends on which of the two transistors has a higher voltage value at the base. If the voltage appearing on circuit line "6 or the voltage value appearing on circuit line 66 exceeds the voltage value that appears at the circuit input, transistor I7I becomes conductive and transistor 172 becomes blocked or non-conductive. Termination of the conducting state of transistor 172 consequently terminates the conducting state of transistor 173.While transistor 172 was conducting, transistor 173 was also conducting, and a voltage signal with a relatively high value was at node 174 due to the effect of the savings divider corresponding to resistors 182, 183 However, the termination of the conducting state of transistor 173 results in a signal with the value of zero or ground potential which appears at node 174 due to the lack of current flow through resistors 182, 133. This output signal can be sent to AND gates 46, 48 in FIG of execution orm as shown in FIG. 2 to provide an injection command signal.

With reference to FIGS. 5, 6 and 7, the mode of operation of the subject matter of the invention will now be explained. One Series of trigger pulses appear on the circuit lines 40, 42 received in complementary form. That means, that the presence of a pulse on the circuit line 40 indicates the absence of a pulse on the circuit line, turg 42 and the presence of a

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Circuit pulse on circuit line 42 indicates the absence of a circuit pulse on circuit line 40. The receipt of a circuit pulse on circuit line 40 causes a current I ₁ to flow to capacitance 603, and a. Current I _{2 flows} to capacitance 6O4. The end of the pulse on the circuit line 40 and the creation of a pulse on the circuit line 42 have the effect that the capacitance 604 'is emptied through the transistor 135 and is immediately charged with the current I., while the current I _? flows to the capacity 6O3 in order to build up another charge there. According to FIG. 7, a curve denoted by 30 is generated, the section between the letters A and B being generated by the flow of the current I ^ into a capacitance 603 or 604, and the section which is one size larger than that at B, the calculating section, by which the flow of the current Ip into the same capacitance is generated. As can be seen, the point B coincides in time with the occurrence of a trigger pulse on the line 42. The circuit line 66 is at a voltage value which represents the highest voltage value of the voltages across the capacitors 603, 604 and to the base of the transistor 72 in FIG Full load enrichment circuit 64 is transmitted, and as soon as its voltage value exceeds the reference value, the current sump 78 comes into operation and draws Strom.om from the circuit line 68, which is then fed to the 12-current source. This results in a reduction in the steepness of the curve SC . As can be seen from Figure 7, the decrease in the steepness of curve 90 when the reference value is located as indicated by the location labeled R and the threshold value is located at 92 results in a lengthening of pulse 94, where the actual degree or extent of the elongation is dependent on the magnitude of the difference between the threshold 92 and the R break point or inflection point, or in other words the degree to which the operation of the engine extends into the full load enrichment request.

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It should be emphasized that the embodiment according to FIG
only al3 example has been chosen and that modifications can be made, for example the circuit 78
also consist of a power source that adds power to that provided by power source 602
will. The holding means 76 can then be designed to stop this additional current from flowing to the proper capacity to achieve the desired slope reduction and attendant pulse lengthening.

All recognizable in the description and in the drawing illustrated technical details are important to the invention.

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Claims (2)

Claims .J Circuit for fuel enrichment at full load or fuel control system of an internal combustion engine with machine scanners, including a scanner for scanning the air consumption of the machine, which generate signals characterizing the operating parameters of the machine, with a computer device, which has a waveform generating device, to a signal with a and having threshold detector means responsive to the engine samplers for producing an output signal having a property indicative of the fuel requirements of the engine and a fuel dispenser having fuel injectors responsive to the output signal and delivering fuel in accordance with the property of the output signal deliver the machine, characterized in that the circuit for fuel enrichment at full load has the following features and devices: a device (84, 86) for Generating a reference signal (R); comparing means (70) receiving the reference signal (R) and a signal from the machine sensing means indicative of the degree of the machine load and determining whether the degree of the load on the machine exceeds a reference value; Switch means (76) having a pair of states which are responsive to the comparison means (70) and switch from a first state to a second state when the machine load signal becomes equal to the reference signal (R); and means (78) responsive to the switch means (76). if they are in one of the states and which modify the waveform of the device generating the waveform. 2. A circuit according to claim 1, characterized in that the device scanning the machine load consists of the scanner (12) for the air consumption of the machine, and 309832/0397 that the value of the reference signal is chosen to be equal to a predetermined high level of air consumption is or corresponds to this. 309832/0397 Le e rs e ι te