DE2030458A1 - Fuel injection system for an internal combustion engine - Google Patents

Description

description
to the patent application

Petrol Injection Limited and Mr. Harold Ernest Jackson, Valley Road, Plyj & on, Plymouth, Devon / England and "Panorama" ,, Vicarage Road, Plympton St. Mary, Devon / England

concerning:

"Fuel injection system for an internal combustion engine"

The invention relates to a fuel injection system for an internal combustion engine, and in particular a system in which fuel injection is intermittent rather than continuous.

In known systems with intermittent injection of the Brennstoff.in timed relation is injected to the engine operation is controlled by a machine driven by the mechanical or electrical arrangement _t wobei.die injection. ''

In accordance with the present invention there is provided a fuel injection system for an internal combustion engine. suggested, with at least one fuel injection arrangement, which at. a fuel flow line is connected, which system according to the invention is characterized by a for the control of the fuel flow fuel shut-off valve actuatable by the injectors to trigger the shut-off valve in operating position in regular time intervals, which control mechanism responds ;; is designed for at least one machine operating parameter

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Adjustment of the period of time * during "the ¹ the Äbsühäitveritil is in the operating position depending on changes in ^T ües" ader ■ - · ^v '^!; Several operating parameters of the machine ". , ■, -., - :, ,,; :

During the operation of the system, dör Brehns-töff, wielcher the injection arrangement is fed / intermittently measured " or delivered, with the time delay ',' during the fuel delivery takes place and thus the amount of fuel "which" of the machine is fed depends on at least one machine operating parameter. The control medium can, for example, be designed as stf be that he passes through the shut-off valve "= for the fuel to" the injector assemblies or nozzles, and the time period or duration adjusted / during the or each shut-off valve remains open. '- -

The control mechanism can be 'trained' to 'generate' electrical excitation impulses for 'actuation' of the 'shut-off valve or the shut-off valves .. The control mechanism can, for example be trained sur generation of "exciter impulses" In "<5eri called regular time intervals', 'and for adjusting' the pulse duration depending on changes to one or more machines ™ operating parameters.

The control mechanism can include an exciter pulse generator in which at least one component is designed to respond to the machine operating parameters and is adjustable to respond changes to this parameter in order to regulate the excitation pulse duration. In a preventive embodiment of the subject matter of the invention, the excitation pulse generator is an astable multivibrator circuit with at least. one resistive ?! Component that appealing is designed on these machine operating parameters and can be set in response to changes in this parameter in order to regulate the excitation pulse duration.

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In another embodiment of the invention, the Control mechanism a reference voltage generator for the generation of a reference voltage that varies periodically over time changes, further a control signal generator for generating a control signal which changes in response to changes this machine parameter changes, as well as an excitation pulse generator, which is responsive to the reference voltage and to the control signal is designed to generate an excitation pulse inmar then, v / enn a certain ratio of the reference voltage relative to the control signal is present. In a certain exit ungsform of this training of the Lrf indun-jsartikel is the reference voltage generator a sawtooth generator and the control signal generator is designed to generate a preload, the level of which changes depending on reductions in this machine operating parameter, wherein the excitation pulse generator is designed to generate an excitation pulse whenever the tensile stress exceeds the preload.

The machine operating parameter corresponds to that of the shut-off valve control mechanism is designed appropriately, the machine supply air or the machine air requirement can be. The system can for example comprise a mechanism which is designed responsive to the engine air demand for generating a control pressure differential in the machine air supply line and can be set to maintain the control pressure difference with an im essentially constant T'ert, with the shut-off valve control mechanism is designed to regulate the shut-off valve actuation period in response to the adjustment of the mechanism which responds to the demand for air.

The system may further include a fuel pressurizing arrangement connected to the fuel flow path and configured to all pressurize the fuel in response to at least one machine operation saver.

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meter, for example also the machine air requirement.

The invention will be explained in more detail below with reference to the accompanying drawings.

Fig. 1 shows a diagram of the fuel injection system according to the invention,

• Fig. 2 is a circuit diagram of a component of the Systems,

Fig. 3 is a longitudinal section through a nozzle,

Figure 4 is an alternate block diagram for the component shown in Figure 2, and

Fig. 5 to

Fig. 8 shows the voltage changes over time

different points of the circuit according to Fig.

In the system shown in Fig. 1, the fuel is a Tankl removed and fed to an appropriately designed pump 2, for example an electrically driven gear pump, from where the fuel arrives in a main line 52. Got from there the fuel in a further conduit 63 at a pressure which is set by a control valve mechanism 100, wherein Excess fuel in the tank 1 via a chamber 53 in the control valve mechanism 100, a line 56, a check valve and a line 61 is returned. Line 63 leads to fuel injectors 83 via a pressure biased valve 63a and excess fuel overflows from the nozzles to tank 1 a throttle 6la and the line 61 back.

The injection arrangements 83 are air-adding excitation coils <operated Nozzles and should be described below. The operation of the fuel dispensing nozzles is controlled by a Control unit 200 as a function of a suitable machine operating parameter: In the system shown is the one in question

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Parameter the machine supply air, as described below. The printing mechanism 100 also works in dependency of the machine supply air and the mode of operation of this mechanism should also be explained further below.

The system further includes an air-fuel enrichment valve 101a, which is advantageous but not essential to the operation of the system.

The function of the injection control unit 200 will be described below to be discribed. The unit is designed in such a way that a pulsating DC voltage is generated when an electrical voltage source 201 is connected, the pulses with a certain constant frequency can be generated. The impulses are the excitation coils of the injection arrangements 83 which are connected to the output terminals of the control unit 200 as shown. the Injection assemblies 83 are accordingly caused to move in regular To open time intervals (depending on the beginning of a pulse from the control unit 200) to meter the fuel, the is fed through line 63. The fuel is injected into the mixture line of the machine and from there into the machine cylinder to be sucked, and when the control pulse from the control unit 200 ends, the injection arrangements close again and the fuel injection ends. As explained in more detail below, depends on the pulse duration - as it is generated by the control unit 200 and thus the period during which the injection arrangements are open depends on the engine supply air.

A circuit diagram of the control unit 200 is shown in FIG. As can be seen from FIG. 2, the control unit is a Combination of a conventional ab astable multivibrator with a complementary power stage 211; if the Voltage source 201 is applied to input terminals 202, a pulsating DC voltage is generated at output terminals 203.

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The circuit shown in Fig. 2 is made up of conventional components and will not be explained in more detail. however, it should be noted that the duration (but not the frequency) of the output pulses can be set in a manner known per se by changing the position of the tap 204 on the potentiometer 205 in the multivibrator stage 210. A useful output pulse frequency is 50 Hz. The control unit (without the potentiometer 205) preferably consists of an assembly consisting of the System is easily removable and easily replaceable in the event of failure. It is for the control unit's pulse generator circuit 200 is not essential that it just corresponds to the circuit arrangement shown in FIG. On the contrary, any known pulse generator circuit can be used. Even other forms of control unit are possible, and an alternative embodiment is described below with reference to FIG Figs. 4 to 8 will be explained.

In Fig. 1 it is indicated that the potentiometer 205 with the tap 204 and the resistor 206 are outside the control unit 200 is located in order to better represent the adjustment of the unit as a function of the machine supply air can. The position of the tap 204 is controlled by a lock 207, which cooperates with a cam follower 208, on which the tap 204 is mounted. The squat 207 is coupled with the control lever 7 of an air valve 4, which is located in the air intake line 3 of the machine, the Air flow is from left to right in the drawing. The function of the air valve 4 will be explained further below. The usual throttle valve 1 is also located in the air intake line 3.

The lever 7 is also coupled to a .Seite one Piston 8A in a cylinder 8B "On the other side of the ·

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Piston is the cylinder 8B via a line 18 with a Throttle 18A connected to chamber 20 in an intake vacuum control unit 102. The vacuum control unit 102 functions via the air valve 4 in such a way that a constant Negative pressure in the air intake line 3 between the air valve 4 and the throttle valve 1 is maintained. The operation of the unit 102 is exactly the same as that of the metering valve control mechanism 102 described in British patent applications 1261/69, 32530/69 and 58515/69.

The chamber 20 of the suction line vacuum control unit 102 can communicate with another chamber 90 in the Unit under the control of a 2IA ball valve that cooperates with a valve seat 22. A control rod 91, which from the chamber 90 through an O-ring gasket 92 into a chamber extends, the ball valve 2IA couples with a membrane 24, which separates the chamber 93 from a further chamber 94 (at Absence of line 130 open to the atmosphere). the Rod 91 can reciprocate within seal 92, and a spring 27 within canister 94 acts on the membrane 24 and thus on the rod 91, so that Lift the ball valve 2IA from its seat 22. One line 29 connects the chamber 93 with the air inlet pipe 3 and the valve 4 and the throttle valve 1, and a pipe 95 with one Throttle 95A connects chamber 20 with chamber 53 of pressure control valve mechanism 100.

It was mentioned above that the chamber 53 takes over excess fuel from the main fuel line 52 and Connect to the fuel tank 1 via a check valve 57 1st. The chamber 53 is actually connected to a chamber 64 of the

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Check valve 57 connected, and the Karoner 64 can under Communicating control through a membrane 58 with the line 61, which leads back to the fuel tank 1, the membrane 58 is through a spring 59 is biased against a valve seat 60 which separates the chamber 64 from the conduit 61 and thereby essentially separates one constant fuel pressure in the chamber 64 and thus also in the chamber 53 is maintained.

j
In operation of the system, the air valve 4 is in the

pressed closed position by a spring 30. If the Throttle valve 1 is opened and the air valve 4 is in the closed position, there is a negative pressure in the Line 29 is generated, which pulls the membrane 24 downwards and thus closes the ball valve 21A. The essentially constant pressure, which is set by the spring-loaded check valve 57, is then fully on via line 18 the piston 8A transferred so that the latter is moved upwards (as can be seen in Fig. 1) and via the lever 7 aas air valve 4 opens. Leakage of fuel via piston SA is returned to tank 1 via line 97. The opening of the air valve 4 reduces the negative pressure in the line 29 and thus opens the ball valve 21A through the membrane 24, whereby fuel can leak from the chamber 20 into the chamber 90 and is returned to the tank 1 via the line 96. The fuel pressure applied to the. KOLBEN JJA works, becomes so is reduced, and the piston moves downwards, as can be seen in FIG. 1, so as to close the air valve 4. In this way adjusts the position of the air valve 4 such that an im substantially constant negative pressure in that part of the air intake line 3 between the throttle valve 1 and the air valve 4 is maintained, the negative pressure is determined by

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the adjustment of the control mechanism 102 and in particular by the bias of the spring 27. It should be noted that, provided that the pressure in the chamber 93, which is required to bring the ball valve 21A in the fully open position, is lower than that Substantially constant check valve pressure, the bias of the spring 30 and the frictional influences of the piston 8A of the linkage 6, 7 etc. are in no way effective for a change in the constant negative pressure in the air intake line 3 in a merldaaren 2IaBe. The value of the throttle 95A is selected so that the ball valve 21A has a desired opening speed.

The air valve 4 is, as mentioned above, with the Potentiometer 205 of the control unit 200 coupled so that when the air valve 4 is opened, the duration of the operating pulses, which the injector assemblies 83 increases and more fuel is metered into the engine.

The construction of the intake manifold vacuum control unit is chosen so that the O-ring seal 92 seals the chamber 93, which is exposed to the negative pressure in the air inlet line 3 between the throttle valve 1 and the valve 4 is generated against the chamber 90 which contains fuel. The seal 92 is partially in a hat in the rod received and partially in a groove in the housing of the unit, and this special construction enables the back and forth-> walking movement of the rod 91 as described above, however, prevents axial movement and creates friction and wear minimal. In particular, there will be a need for sliding or circumferential seals between negative pressure zones and pressurized fuel zones avoided.

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An injection assembly or nozzle 83 is in the each shown in Fig. 3. The nozzle v / eist a fuel inlet 41, which is in operation with the fuel feed line 63 communicates. The inlet 140 communicates via a passage 141 with the interior of a tubular Interrupter valve member 142, which in turn has openings 143 in the valve member with a chamber 144 communicates. A spring 145 is supported on an end portion of the valve member 142 and biases the valve member against a seat 146, in which position the communication between the chamber 144 and a fuel pipe 147 is interrupted by the valve member. The fuel tube 147 is a tube made of corrosion-resistant Small diameter steel in alignment with an outlet port 148 in an outer shell 149 which encloses the tube. The space between the tube 147 and the shell 149 is ventilated through openings 150. A movement of the Valve member 142 is controlled by an excitation coil 151 in which the valve member is partly arranged. The valve member 142 or at least that part of the same, which is located inside the excitation coil, consists of magnetizable material, so that an excitation of the excitation coil 151 lifts the valve member from its seat 146 and thus the fuel flow into the Fuel pipe 147 allowed. The fuel is discharged through the outlet port 148 into a mixture induction line of the engine injected, air being sucked into the shell 149 through the openings 150. During operation of the injection system according to FIG. 1 is the excitation coil 151 to the output terminals of the control unit 200 connected, the valve member 142 is moved into the open position at regular time intervals and in held this position for a period of time that is determined by the duration of the output pulses of the unit 200.

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The use of air admixing nozzles as in Fig. 3 shown is advantageous in that the influence of the fuel flow on the negative pressure in the intake manifold, in which the; Nozzles are arranged in this way is eliminated. If no air admixing nozzles are used, the Influence can be eliminated by placing the outer surface (as shown in the drawing) of the liembran of the check valve exposed to suction line vacuum. The nozzle shown in Fig. 3 has the further advantage that the fuel tube 147 acts as a fuel throttle and if a llehrzanl of nozzles in a system is used, serves to equalize the fuel distribution between the individual nozzles. It should be noted that the application of the in Fig. The system shown in FIG. 1 does not apply to the system shown in FIG is limited.

It was mentioned above that the valve mechanism 100 controls the pressure under which fuel is supplied to the injection devices 83. Mechanism 100 is exactly the same as pressure control mechanism 100 described in British Patent Applications 1261/69, 32530/69 and 58515/69 and operates to increase the pressure of fuel supplied to fuel assemblies 83 as the air flow passes through the suction line 3 increases. For this purpose, the line 3 comprises a slot 41 which is closed at the end and which communicates with a line 43 which, in turn, is in communication with a chamber 45 in the control mechanism 100 via a throttle. A liembran 47 defining the chamber 45 is connected to one end of a control rod 110 similar to the rod 91 in the unit 102, which extends through a seal 111 into the chamber 53 and at its other end

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Pressure control valve member 112 carries. The valve member 112 acts. with a valve seat 113 together to control the fuel flow from main line 52 to chamber 53 * the rod can pivot movement in seal 111 in a similar manner to that described above for rod 91, and the movement of the valve member 112. is over the rod or the Rod controlled by membrane 47. The chamber 53 is connected to the check valve 57 by means of the line 56, as above, described with the chamber 53 set at the substantially constant check valve pressure.

When the machine is at a standstill, the atmospheric pressure is in entire air inlet 3 in front of and accordingly also in the chamber 45. A chamber 131 on the other side of the membrane 47 to the chamber 45 is the same in the absence of a line 130 Exposed to atmospheric pressure, so that no Pressure difference results. The pressure in the lines 52 and 63 is accordingly the same as that in the chamber 53. When running Machine and a minimal air consumption (i.e. in idle mode) the position of the air valve 4 is such that the right-hand end of the slot 41 is just to the right of the air valve 4 lies (this position is shown in Fig. 1). As a result, a small fraction of the constant will be in the air intake line Transferred excess pressure developed between the throttle valve 1 and the air valve 4 to the line 43.

The enrichment valve 1O1A (see below in more detail is explained), is normally open, and only so much should be noted here that under these circumstances and with The absence of line 130 via the atmospheric air. Restrictions 66A and 66B in valve 10IA enter line 43 can and thus the negative pressure signal that the diaphragm '47

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can affect. That affected The negative pressure signal at the diaphragm 47 acts via the rod such that the valve member 112 is displaced towards its seat, and as a result, the fuel pressure increases in the feed lines 52 and 63 until equilibrium is reached again. With increasing air consumption of the machine the air valve 4 opens further and thus sets a larger one Length of the slot 41 the constant negative pressure between the Throttle valve 1 and the air valve 4 off. The increased negative pressure (which in turn is impaired by atmospheric Air, which through the throttles 66A and 66B in the valve IOIA Has access) the Heinbran 47 is abandoned and leads to a increasing closing force on the valve member 112, which further increases the fuel pressure in the supply lines 52 and 63. If the throttle valve 1 suddenly opens during acceleration the negative pressure between the throttle valve 1 and your air valve 4 rises suddenly. This increase is effective immediately on the diaphragm 47 and the valve member 112 that the fuel pressure in lines 52 and 63 increases.

It is understood, however, that the application of the pressure control mechanism 100 according to FIG. 1 is not essential for the system and that another embodiment of a fuel pressure device Could apply.

The check valve 57, which, as mentioned above, a substantially constant pressure in chamber 53, and a predetermined minimum pressure value in the supply lines and 63 maintains "is preferably set so that the The minimum pressure value is large enough to ensure that the fuel remains liquid in the system at all times, even if

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the fuel temperature is significantly higher than the normal ambient temperature should increase.

The spring loaded check valve 63A in the fuel supply line su the lens fuel arrangements 83 is used Enrichment of the fuel-air mixture that the lens syringe assemblies is to be supplied under machine acceleration conditions, as can be seen from the following example:

It is assumed that the normal negative pressure between the throttle valve 1 and the air valve 4 in the suction line is 25 mm of mercury, that also the resulting Fuel pressure in the supply line 63 517 Torr is that the ira essential constant linear pressure generated by the Check valve 57 is predetermined, is at 775.5 Torr and that the valve 63A is biased by a spring 76 which gives a substantially constant load equivalent to a value of 878.9 torr. Under steady conditions the is Fuel metering pressure then 517 plus 775.5 minus 878.9 = 413.6 torr.

In the event of sudden acceleration before the position of the air valve 4 has been adjusted, the negative pressure increases between the throttle valve 1 and the air valve 4 momentarily at, for example, 50 mm of mercury. This will turn the fuel pressure in line 63 to 1034 torr raised. The metering pressure is now 1034 plus 775.5 minus 878.9 = 930.6 Torr. While accordingly the negative pressure is in proportion 2: 1 has changed, the fuel metering pressure has changed in the ratio 2.25: 1, so that fuel enrichment occurs results during acceleration. As soon as the air valve 4 has opened to restore the vacuum of 25 mm Mercury between the throttle valve 1 and the air valve 4

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the pulp metering pressure returns to its original fourth back, but the new position of the air valve 4 is accompanied of a readjustment of the potentiometer 205.

The valve 83ä also has a secondary, but important one Function, namely to prevent fuel from reaching the Injection assemblies is dispensed as long as the machine does not is in operation.

From the above description it can be seen that when the system is in operation, the fuel is metered into the fuel injection assemblies 83 at a pressure which depends on the engine air requirement , and that the injection assemblies open at regular time intervals, but remain open for a period of time which also depends on Machine air requirement. It goes without saying, however, that it is not absolutely necessary that the fuel pressure is controlled by the machine supply air and that another machine operating parameter could be used. Alternatively, several operating parameters, one of which is the machine supply air, can be used as control variables. In addition, the use of the machine air requirement for determining the length of time during which the injection nozzles remain open is not part of the invention, and another machine operating device could be used; alternatively, several operating parameters can be used, one of which is the machine air requirement could be. If any control is effected using the engine air demand, it will be understood that it is not essential to the arrangement to take advantage of the maintenance of a constant engine air pressure in the engine air manifold.
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It is also understood that the one shown in FIG Arrangement for maintaining a constant negative pressure in the air supply line 3 and the resulting Control of the control unit 200 and the pressure control valve mechanism 100 could be replaced with an arrangement similar to that shown in Figure 1 of the UK patent applications 1261/69, 32530/69 and 58515/69 is shown.

The above-mentioned valve 101 is a manually operable one Valve for enriching the fuel-air mixture supplied to the machine, for example in the event that the machine is running is cold. The operation of the IOIA valve will now be explained will.

When valve 1017 * is open, atmospheric air can enter as explained above, via line 43 and throttles 6βΑ and'66B in the valves The throttle 66A can be closed by hand to ground to throttle the flow of atmospheric air into line 43 and thus increasing the effective negative pressure that is applied to the membrane, and thus the fuel pressure in the lines 52 and 63 increase. The result is that the machine is one richer fuel-air mixture is obtained. The throttle 66B that remains open under all operating conditions, but is adjustable for changing the zero setting of valve 101A. '·

It will be understood that while valve 101A has been referred to above as a cold start auxiliary device, its application is not limited to this case and could be used as a manually operated valve iromer when a richer fuel-air mixture is required. ^It: should be further understood that the valve does not necessarily 10ia

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must be provided for the function of the intake manifold vacuum control unit 102 or (at most to the extent that a throttling 66A, 66B \ ar is seen, through the atmospheric air into the Line 43 arrives) for the function of the pressure control mechanism 100: the valve IQ1A could accordingly also be omitted.

The line indicated in FIG. 1 with dashed lines 130, which was initially assumed not to be present above, connects the air inlet line 3 on the atmospheric pressure side the throttle valve 1 or the air valve 4 with the chamber 94 in the intake manifold vacuum control unit 102 and also with the chamber 131 in the pressure control mechanism 100 and the atmospheric air inlet of the enrichment valve 101A. The task this line 130 is to compensate for any influence on the negative pressure between the throttle valve 1 and the air valve 4, which could result from the flow resistance of the air filter, which is normally in the air inlet of an air inlet duct 3 is arranged. This flow resistance could be a special one have a noticeable effect when the machine is fully loaded: The line 130 is but not necessary for operation, and chambers 131 and 94 as well the inlet of valve 10IA could also be vented to atmosphere as described above.

The alternative embodiment of a control unit mentioned above and shown in FIGS. 4-8 could replace the control unit 200 with the potentiometer 205 according to FIGS. The components of the control unit, which is now to be explained, are shown diagrammatically in FIG and comprise a saw tooth generator 301, the output of which is connected to the input of a trigger circuit 302. The trigger circuit 302 generates the excitation pulses for the

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Injection devices 83, including the output of the trigger circuit 302 is connected to the excitation coils of the lens syringe assembly 83 via a power amplifier 303 of the trigger circuit 302 is also fed back to the input of the sawtooth generator 301 via a feedback network 304

The sawtooth generator 301 generates an output voltage constant frequency, v / ie shown in FIG. 5: a useful value is, for example, 50 Hz. The trigger circuit 302 generates a square wave output pulse, .V7enn the input of generator 301 exceeds a predetermined threshold value determined by a control circuit 303. This predetermined value is variable depending on the machine supply air, as described below, in order to set the duration of the output pulse of the trigger circuit. The output frequency of the trigger circuit However, 302 is constant and corresponds to the output frequency of generator 301.

The control circuit 303 further comprises an oscillator 304, a variable inductance 305 and a rectifier network 306. The oscillator 304 generates an output of fixed frequency, for example 1000 Hz, that of the variable inductance 305 is supplied. The inductance 305 is connected to the air valve 4 in a manner known per se (as indicated at 300A in FIG. 4) coupled in the machine air intake line 3 (Fig. 1), wherein a movement of the air valve 4 in the sense of maintaining a constant negative pressure in the intake air line 3, as above described, the adjustment of the inductance 305 causes. The inductance 305 can be used, for example, with the air valve lever 7 be coupled via a cam and cam follower in the same way as described above and explained in Fig. 1 for the "

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Potentiometer 205. The Jus days of the inductance 305 changes the amplitude of the output of oscillator 304, and the modified output is fed to the rectifier unit 306. In this network the signal is rectified and smoothed / to generate a DC bias signal which the trigger circuit 302 is activated. The level of the DC bias signal depends on the amplitude of the input of the Rectifier network 306 and therefore from the machine air requirement.

Fig. 5 to 8 show the reduction in the voltage versus time at various points of the circuit of Fig. 4. Fig. 5 shows the output of the sawtooth generator 301, and Fig. Indicates the entrance of Gleichrichternetstwerks 306 for three Vierte.U ₁ , X ₀ and X- of the inductance 305 (ie for three different values of the line air requirement s). Figure 7 shows the output of rectifier mains 306 for the same three values of inductance.

8 illustrates the manner in which the DC bias from control circuit 303 controls the operation of trigger circuit 302. In Fig. 8d the DC bias signals for the inductance values X 1, K ^ and X_ superimposed on the output of the generator 301 are shown. The trigger circuit 302 generates an output pulse when the output of the generator 301 exceeds the bias signal from the control circuit; 8a, 8b and 8c show the output of the trigger circuit 302 for inductance values X ₃ , X ^ ^ ^2W · ^ ₁ * ¹¹¹ ^ o it can be seen that the output frequency of the trigger circuit remains constant, but that the duration of the trigger circuit output pulses decreases when the equal bias level applied to control circuit 303 increases. The duration of the trigger circuit output impulse determines the duration during

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which the injectors 83 are open. The length of time during which the injection nozzles 83 are open accordingly depends on the engine supply air or the machine air requirement as well as with the control unit according to FIG. 2.

The components shown in diagram form in Fig. 4, i.e., generator 301, trigger circuit 302, etc. are in themselves are known and therefore do not need to be explained in detail here. It is understood, however, that the sawtooth generator could be replaced by a generator which any other outputs corresponding reference voltage waveform. Furthermore can also other arrangements can be used (instead of the oscillator and the variable inductance 305 in the illustrated embodiment fom), UTii to generate an oscillating control signal whose /jr.plitude depends on the line air requirement.

The guidance last described is preferably in the form the control unit is also designed as an assembly that can be easily removed from the fuel injection system and in the Case of failure is easily replaceable.

Finally, it should be noted that although the system shown has a large number of lens syringe assemblies 83 each with a coil-operated shut-off valve, however this is not essential to the invention, and the large number of exciter coil actuated Lens injection arrangements could, for example, be replaced by a single exciter coil-operated interrupter or shut-off valve, which can be activated intermittently by the control unit 200 (FIG. 1), to fuel a plurality to be supplied from open injection nozzles via corresponding pressure-controlled control valves. Line arrangement of this Eauart is in the British patent application 58327/69.

Claims

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Claims (20)

*1 Claims Fuel injection system for an internal combustion engine iit at least one fuel injector attached to a Fuel tarnishing path is included, can drawn through ain for controlling the flow of fuel through the Injectors actuatable fuel shut-off valve and through a Gtauarmeclianism for the shut-off valve for triggering of the shut-off valve in operating position at time intervals according to the rate, which damming mechanism is designed to respond to at least one machine operating parameter for regulation the Seitdauar, - during the yes shut-off valve in Ietriabsstellung is one or more, depending on changes Eat & ebspararieter dar! Machine. 2. fuel injection system according to claim 1, «.ladurc'x ge ■ marked that the stevedore structure is designed for: 1 ie the opening of the shut-off valve for fuel: passage to the Ziinspritzdüsan and for dx2 Sinragulieruny the opening time of the shut-off valve. 3. Fuel fine injection system according to claim 1 or 2, characterized in that marked that the control mechanism for the generation of electrical power Excitation pulses for the actuation of the shut-off valve is trained. . ! 4. A fuel injection system according to claim 3, characterized gakennselehnet, da.C en regular Seitintervallan is the Stauemechanisinus for diafeRzeugung of Erregerirnpulsen in · * "formed and di ^r ji" Jinragulieruncr Pulsclauer the function of a:.. 1er .Maschinanbetriebsparameter.. . · 00 98 82/1 BU
BATH 5. Fuel injection system according to claim 3 or 4, characterized in that the control mechanism comprises an excitation pulse generator, at least one of which is a component is designed to be responsive to a machine operating parameter and can be adjusted as a function of changes this parameter for regulating the excitation pulse duration. . 6. Fuel injection system according to claim 5, characterized in that that the excitation pulse generator is an astable multivibrator circuit is, with at least one resistive component, which is designed responsive to a Maschirienbetre $ .bparameter and can be adjusted depending on changes in the same. 7. Fuel injection system according to claim 4, characterized in that that the control mechanism is a reference voltage generator includes, which for the generation of a.Bezugsspannurig is designed that changes periodically over time that the control mechanism further comprises a control signal generator which is adapted to generate a control signal which ψ changes as a function of changes in a machine operating parameter, and that the control mechanism comprises an excitation pulse generator which, in response to the reference voltage and the control signal, is designed to generate an excitation pulse when a predetermined ratio of the reference voltage to the control signal is present. 8. Fuel injection system according to claim 7, characterized in that that the reference voltage generator is a sawtooth generator, and the control signal generator for the generation a bias voltage, the level of which varies depending on 009 882 / 1.5 UU speed of the machine parameters changes, the excitation pulse generator for generating an excitation pulse exceeding the preload is formed by the reference voltage. 9. Fuel injection system according to claim 7 or 8, characterized in that the control signal generator means for includes the generation of an alternating voltage, the amplitude of which is dependent on reductions in the machine's operating parameters changes. 10. Fuel injection system according to claim 9, characterized in that da3 the alternating voltage generator has an inductive component which is responsive to the machine operating parameter and can be adjusted depending on changes in this parameter to change the amplitude of the alternating voltage. 11. Fuel injection system according to one of claims 1 to lo, characterized in that the machine operating parameter is the machine air requirement. 12. The fuel injection system according to claim 11, characterized by a mechanism responsive to the engine air requirement which is designed for generating a control pressure difference in the engine air supply path and is adjustable to maintain the control pressure difference at a substantially constant level, the cut-off valve control mechanism being designed for balancing the shut-off valve operating period depending on the setting of the air demand-responsive mechanism. 13. Fuel injection system according to one of claims 1 to 12, characterized by a pressurizing the fuel Assembly peeled into the fuel flow path and so pressurizing the fuel depending on at least a machine operating parameter is formed. 009 882 / 15- £ A 14. Fuel injection system according to claim 13, characterized in that that the machine operating parameter is machine air demand. 15. Fuel injection system according to claim 14, characterized by a mechanism responsive to the machine air requirement, which is designed to generate a control pressure difference in the engine air supply path and for the maintenance shark direction of the control pressure difference at an essentially constant Value, wherein the fuel pressure generating arrangement is designed for changing the pressure under which the fuel flows to the injection nozzles depending on the setting of the mechanism responding to the machine air demand. 16. Fuel injection system according to one of claims 12 or 15, characterized in that the mechanism responsive to the machine air demand comprises an air valve which is in the machine supply air line is arranged to generate the control pressure difference, and that the position of the ventilation valve is adjustable is to maintain the control pressure differential at the constant value. 17. Fuel injection system according to claim 16, characterized in that that the mechanism responsive to the demand for air comprises an air valve control arrangement which is designed to be responsive is to a different value of the control pressure difference than the constant value for changing a control fluid pressure to which the Air valve responds to adjust the position of the air valve. 009882 / 15U BATH 0 |} Öi | SMtt. Γ ,, 18. Fuel injection system according to one of claims 1 to 17, characterized by a plurality of shut-off valves, all of which are operable to control the flow of fuel through an associated injector. 19. Fuel injection system according to one of claims 1 to 17, characterized by a single shut-off valve which can be actuated to control the flow of fuel to a plurality of injection nozzles. 20. Fuel injection system according to one of claims 1 to 18, characterized in that the injection nozzle or nozzles a Include fuel tube disposed within an outer shell and a fuel outlet in alignment with an exit port the outer shell, and that the fuel nozzle or nozzles have an electromagnetically actuated shut-off valve member have, which is movable to change the fuel passage through the fuel pipe, wherein the outer shell has at least one ventilation opening has, through which air can be sucked into the outer shell during the fuel flow through the outlet opening. 009882 / 15U BATH ORIGINAL