DE1960144C - Fuel injection system for mixture-compressing externally ignited internal combustion engines with continuous injection into the intake manifold - Google Patents

Description

The invention relates to a fuel. The object of the invention is to provide a To develop injection system for mixture-compressing external-ignition fuel injection system in which the ·> Dete internal combustion engines with continuous metered fuel quantity as proportionally as possible injection into the intake manifold, in which there is a measuring element and the amount of air flowing through the intake manifold, like an arbitrarily actuated throttle valve behind - 5 whereby the relationship between the applied force to each other are arranged and the measuring element depends on the amount of substance and the amount of air accordingly the amount of air flowing through can be changed via an Ar motor parameters. working member is moved against a restoring force and this object is thereby achieved according to the invention the moving part of one in the fuel releases that pressure fluid serves as a restoring force, the Line arranged valve for the metering of a ίο continuously and under constant, however arbitrary Amount of air proportional to the amount of fuel lent changeable pressure provided by a pressure line. 'promotes the working link applied. - In fuel injection systems of this type, the one that should bring about the restoring force of the measuring element the distance covered by the measuring element as possible pro the pressure of the liquid is kept constant, proportional to the Lμft-15 flowing through the intake manifold, however, depending on the engine parameters quantity rope. ·, so that with simple means at the metering a change in the hydraulic pressure and thus the valve, a restoring force proportional to this air flow rate takes place, in which case this corresponds to the required amount of fuel can be allocated. For this purpose, the internal combustion engine is appropriate it is necessary that the restoring force on the measuring new pressure is kept constant, organ in every position of the measuring organ as close as possible. An advantageous embodiment of the invention is is kept constant. such that the pressure generating the restoring force

In the case of a known fuel injection system, this fluid is dependent on at least one

This type (German Auslegeschrift 1234917) is pressure control valve controlled by engine parameters

although already proposed, as a restoring force on the changeable and that the pressure control valve is current-

Measuring element to use a spring or the like, ie at- »5 downwards of the working element in the pressure line.

for example also a hydraulic force, but it is arranged

There is no provision for the restoring force via the adjustment path to keep the measuring element constant. To get the special advantage that the change of the back line The most accurate possible measurement of the liquid pressure generated by the suction force is not possible In order to obtain the volume of air flowing through the pipe, it should be done in the vicinity of the throttle valve, but rather Steering of the measuring element should be as large as possible. Since transmitted through appropriate lines to a however, especially with a spring, the restoring force can take place at any point. Should z. B. the throttle dem Path changes, the spring must for a satisfactory flap position with as an engine parameter in this constant restoring force be very soft and long, changes in pressure are taken into account, so d. H. have a flat characteristic. This has to be done by the pressure control valve in the vicinity of the throttle constructive the disadvantage that the entire flap can be arranged without the throttle dimensions the fuel injection system ratio flap for its part again in the vicinity of the measuring element get moderately large. In addition, the must then be what to avoid fluidic spring force due to transverse vibrations of the spring, see the influences between the throttle valve and measuring rods, which may be required by shaking the motor. So it is without weivechallenged will. more possible, the measuring element with the metering valve

Should the relationship between the amount of air and its relatively large dimensions be

can be changed the amount of fuel added, z. B .. to be attached to the air filter indirectly, but the

by "enriching" this mixture when starting the throttle valve itself, advantageously immediately

of the internal combustion engine, this can be arranged by changing 45 in front of the main intake manifold section

the restoring force of the measuring element as a function of the individual leading to the motor cylinder

of any engine parameters. Branch off the pipe socket. Incompressibility too

In another known fuel injection system, a fluid is used as a restoring force

system (German Auslegeschrift 1281 746) as a retroactive regulation.

adjusting force on the measuring element is a spring, the force of which is 50. A further advantageous embodiment of the invention

is kept constant on the measuring element, manure is such that the working element with the moving

that the lever arm over which the spring is designed on the borrowed part of the flow divider valve

Measuring organ acts, changes. At full load is coupled by valve and that the working member as

To reduce the restoring force, a fuel-injecting piston is formed in a cylinder bore

assurance. In another known fuel inlet, 55 works in its connection channel to the pressure line

Spray system of this type (US Pat. No. 2 583 406) a throttle is arranged.

acts as a restoring force on the measuring element. This dampens the actuating movement

the one whose bias reaches the other of the measuring element depending on the temperature, whereby a more uniform

is cash. With the German Auslegeschrift 1 281 746 running of the engine is achieved

and US Pat. No. 2,583,406 is exclusively 60 According to an additional embodiment of the invention

The use of a spring force as a return is that caused by the pressure control valve

Stellkraft thought, whereby the already above on-itself constant pressure depending on either

Outstanding disadvantages result. One would the springs of the throttle position and / or of the

Replace it with a hydraulic restoring force, so downstream of the throttle valve in the intake manifold

the devices would have to be provided, which in 65 setting pressure and / or depending on

Dependence on the adjustment path of the measuring element the speed of at least one temperature parameter

Correct the pressure of the fluid to a constant changeable. As a transfer element of the engine characteristic

To obtain restoring force. large on the pressure control valve can be a

Cam, a space cam or electrical variables are used.

A preferred embodiment of the invention is that the point in the flow divider at which the injection quantity is metered and the point at which the surface of the working member is acted upon are connected one behind the other in the direction of flow, with a pressure reducing valve at least i _D shape between the said points Throttle is switched. There are thus two hydraulic circuits with different pressure for the reset and for the metering, whereby pressure fluctuations z. B. have little influence on the pressure and thus the control accuracy _{in the} second system by flowing fuel in one system.

Embodiments of the invention are shown in simplified form in the drawing. It shows

Return line 20, into which a pressure limiting valve (pressure control valve) 21 is connected. From line 19 of the fuel reaches a _j »» housing the Zumeßventüs 8 shippers *> ***} _ ** ·

This channel 22 opens into an annular groove ZZ a, tue is arranged in the housing of the metering valve 8, \ un bores 22fe to Zy ¹ * ^ ™ ^ nmr, which the slide 12 is guided as close as possible axially vra * "bar The bores 22 b . mouth it ^ n

the cylinder bore 23 ^ ^ in "fte'ie, T" _ne edros - slide 12 an annular groove 24 ^ t. ^ o ^ gedro since with the annular groove 22 α in ^Ve {* ° ^d " ⁿ ^ according to the position of the control slide.12 «Λ <^. the control slots 25 covered. Au ^ n ^S ^ ^e rscn

> 5 zen 25 reaches ^ der ^ raftstofl m Kanal ', 2b, me individual not shown to Enspn ^ snme intake manifold of the internal combustion engine lead out

one.

35

sfersss μ *.

of the moving part of the metering valve, this

Fig. 7, ⁸ a section along the line VIII-VlII as through which the |

in Fig. 8 by a pressure control valve that can be attenuated with a. in the

temperature-dependent controlled member works, wel- i D ^

this at the same time controls a bypass of the suction pipe, _Fi ^g g. 8 shows a section along the line VII-VII » ^Fl I ^g n in FIG. 1, the combustion air flows in the direction of the arrow through an air filter 2 arranged in a housing 1, an intake pipe section 3 in which a measuring element 4 is arranged, a connecting hose S and an intake pipe section 6 with an arbitrarily actuatable throttle valve 7 to one or more not shown Cylinders of an internal combustion engine. The measuring element 4 is a transverse to; Current

one

benfahs

seat valve 27 «formed, ^!

as * ™ ^ ™ * £ der
very slight. Movement of the full ^^ en ^ ira ^^ as «Jen. the

goffbehalter

_{Opening your} around.

1 _n the force ⁿ _{by a}

through is ^changeable .

the suction amount of air flowing wherein for a constant force acting on the throttle member 4 restoring force as well as a constant prevailing in front of the throttle device 4 air pressure, the pressure prevailing between the measuring element 4 and the throttle valve 7 pressure also Ä ^b 4 controls directly a as supply bar he ^ throttle

is very versatile,
^Dr ^ movement of the

ber ^ e ,. ver β ^^

Front on 37 rotating

ΖΛ1Γ UUCIUiIgUIIg UU ΐν.οιν., Ν, .... ,, - .. ,,

organs 4 is a lever 10 connected to it, which is mounted on a shaft 9 as smoothly as possible and during its pivoting movement with a nose 11, the movable valve part 12 designed as a slide of the metering valve 8 is actuated. The nose 11 facing away Front side 13 of slide 12 is acted upon by hydraulic fluid, which acts as a restoring force for the Measuring element 4 is used. The rest position of the lever 10 is determined by an adjusting screw 14.

The fuel is supplied via a fuel pump 16 which, driven by an electric motor 17, the fuel is drawn in from a container 18 and it is fed through a line 19 to the metering valve 8 - ■ ~

i the force of a iSi · The space cam 40 is scanned, whose position edcrtelllr 41 on the spring 31 ^ fg ^^ _{pretensioning} the pressure for transfer «| Γ £ ^üere _messor J _ans determined. 4

^d 'From JS line 27 branches off a line 67, which leads from to line * ^ "^ _{68 to}

to a two return flow 69 depressurized to the

^, ^ get. By the Druek-J ^ der Press for the restoring force of the

* £ ^ { ₂ k ™ of _the measuring element 4 as a function of pushing 12 or ^ of the fe ^ _Όη ^ _

The control valve is a flat seat valve 70, the 32 of which is the force of the spring 31 of the pressure control valve 28 Flow through a membrane 71 is controlled, is changed. For example, at full load the which in turn by a spring 72 in the Schlicßrich throttle valve in a position in which the intake manifold direction of the valve is loaded. The fuel flows fully open, so one desires the highest Leialso via the line 67 and the valve 70 in a 5 stung, d. H. a relatively rich mixture. Since the VorRaum 73 and from there pressureless via the return tension of the spring 31 of the throttle control valve 28 69 to the fuel tank 18.Determines the pressure of the fuel, which the front

The fuel tank 8 is pressurized under atmospheric ropes 13 of the slide 12, the must on Shem pressure, so that in the space 73 approximately measuring element 4 acting restoring force low ver atmospheric pressure prevails. The space 73 is reduced so that the slide 12 is displaced into a position separated by the membrane 71, the spring 72 in which the control slots 25 The taking space 74 is a part of a throttle which are more open and a correspondingly larger one flap of the intake manifold bypass line 75, fuel quantity reaches the injection. Vice versa 75 a, of which only the mouths in the intake manifold takes place in partial load operation by a relatively higher and in the pressure control valve 68 are shown. In 15 pressure on the end face 13 of the slide 12 in this space 74, a piston slide 76 is arranged with a small deflection of the measuring element 4, as a result of which net, which the cross-section of the bypass air line 75.75 ο the mixture is depleted.

controls and which also acts as a spring plate of the spring In push mode, however, is due to the

72 serves. There is a negative pressure in the suction pipe of the space cams 32

The adjustment of this piston valve 76 takes place ao very far against the force of the spring 38 verschodurch a temperature-dependent member 78 ben so that the spring 31 of the pressure control valve strong (Expansion regulator), which means that the feet are tightened when the engine is cold. This creates the restoring force the 72 less compressed and the bypass 75 of the measuring element 4 increased accordingly, so that despite is wider than when the engine is warm. Dem- the small »air leakage« that is inherent in the as a result, when the engine is cold, more fluid flows past the closed throttle valve, none through the valve 70 and thus the pressure of the liquid acting as a deflection of the measuring element 4 and thus no force-restoring force is lower and the substance is injected.

The amount of fuel injected in relation to the air As long as the engine is cold, the amount of pressure increases. control valve 68 enriches the fuel in the

The mode of operation of the fuel-air mixture described is achieved because the pressure serving as the reset injection system when the motor is at operating temperature is reduced tors is as follows: part of the air flowing through the bypass duct 75 is

When the internal combustion engine is running, the measuring element 4 is deflected more strongly than the throttle of the pump 16 driven by the electric motor 17 corresponds to the valve position, so that the fuel is sucked in from the fuel tank 18 accordingly, more fuel is already added to this deflection. and the metering valve 8 is measured via line 19.

leads. At the same time, the internal combustion engine increases the pressure of the fuel which the end face 13

Air is sucked in via the suction pipe 3, 5, 6, acted upon by the slide 12 and as a restoring force the measuring element 4 acts a certain deflection from its of the measuring element 4, is therefore constant per se Experiences rest position. 40 and only depending on the engine

According to this deflection of the measuring element 4 sizes, in the embodiment described the slide 12 is also shifted from the position of the throttle valve, ie load-dependent, via the lever 10, which thereby has a larger cross-section of the gig, as well as from the negative pressure in the intake manifold, ie Control slot 25 releases. The resulting changes to the Mo- also speed-dependent, The amount of fuel reaching the gate valves thus corresponds to 45 In F i g. 2 is the one containing the pressure control valve with the manipulated variable of the measuring element 4. Shown from the annular groove part of the fuel injection system. At die-24, the remaining fuel continues to flow to the forehead bcite of the slide 12 and from there to the parallel spring 31 of the pressure control valve 28 through a Kurgeschaltet Drucksteuerventflen 28 and 68. venscheibe 43 changed only by the

The direct coupling of the measuring element 4 with the 50 prevailing downstream of the throttle valve in the intake manifold Control slide 12 results in a constant ratio of pressure is axially displaced. For this purpose, the curve of air volume and metered fuel volume, disk 43 is mounted on rollers 44. The adjusting movement provided that the characteristic curves of these two organs are likewise sufficiently linear by means of a pin 40 on the spring, which is sought in itself. plate 41 transferred. So the throttle valve is at a standstill The air-fuel ratio would then be over the 55 here in no connection with the cam, be constant over the entire operating range of the engine. It The change in the preload of the spring 31 and however, as stated at the beginning, it is necessary, depending on the change in the restoring force of the measuring section of the operating range of the engine, the organ 4 is therefore speed-dependent and the load-fuel-air mixture is richer or poorer-dependent.

th what according to the invention by changing the 60 in the embodiment shown inFig.3 Restoring force of the measuring element 4 takes place. however, the pin 40 is by a cam

Measured variables for load and speed are adjusted throttle 46 on the shaft 33 of the throttle valve 7 flap position and intake manifold vacuum, so that it is fixed, so that when the throttle return force is adjusted, it is useful depending on the flap 7, i.e. rotation of the shaft 33 by the sen is changed. This takes place in that each nacfl 65 lever 34, the pin 40 through the cam 46 Position of the throttle valve 7 or depending on the height of the adjusted. So here one only takes place depending on the load Pressure in the suction pipe by changing the restoring force of the measuring element 4 accordingly. rotate or axially shift the space cam in the pressure control valve shown in Fig. 4

249C fr

becomes as in Fig. 1 the: bias of the spring31 changed by a Rauinnocken 32. In contrast to the exemplary embodiment shown in FIG. 1, however, there is an opening in the membrane 29 48 is provided, via which the fuel can flow after exiting the line 27 from the space 49 delimited by the membrane into the space 50, which receives the spring 31, and from there back to the fuel tank 18 via the line 30 prevailing pressure on both sides of the membrane 29 and thus a possible change in the Pressure in the fuel tank has no actuating effect on the diaphragm.

In order to be able to control larger correction factors on the pressure control valve, the in FIG. 5 shown metering valve in the channel section 22c Pressure reducing valve 52 interposed. The pressure reducing valve is here as a simple diaphragm valve shown, the membrane 53 on the one hand by the * » inflowing fuel is applied and on the other hand by the force of a spring 54 and the atmospheric pressure flowing in through opening 55.

To prevent the slide 12 of the feeder * 5 meßventils8 due to any air pressure surges prevailing in the intake manifold, which would be transmitted to him via the measuring element 4, undesirably and is pushed back, which leads to uneven fuel injection and thus jerky driving. is shown in FIG. 6 shows an exemplary embodiment in which, via a disk 57, the end face is attached to the slide 12, the movement of the slide 12 and thus of the measuring element 4 is braked and is dampened. For this purpose, the slide 12 dips with its end face 13 into a cylindrical space one, which has approximately the diameter of the disk 57 and through the disk 57 into two space sections 58 a and 585 is shared. The two room sections 58 a and 58 & are connected to the channel 22 c by throttle bores 23 a and 60, respectively. Since the area of the disc acted upon by the fuel in space 58 a 57 is larger than the area acted upon in space 586, the bores 23 α and 60 must be dimensioned so that the damping effect in both * S Movement directions of the slide 12 is the same.

In that shown in FIG. 7 and FIG Embodiment are the pressure control valves 28 and 68 of Fig. 1 to a pressure control member 28 ' Assembled Here, too, the spring 31 'is, as in the first exemplary embodiment, by means of a space cam 32 'can be changed in their force. In addition, however, acts as a motor parameter for the transmission of the temperature Another expansion regulator 62 on the spring 31 '. This expansion regulator acts indirectly via the slide About 63 on one arm of a double-armed lever 64, which with its pivot point 64 a on the spring 31 'acts and the space cam 32' acts on the other arm to guide the lever 64 this is attached to the bracket 65 in the housing. The slide 63 also creates an idle channel 66 controlled, which as in the example according to F i g. 1 the section located upstream of the throttle valve of the intake manifold with the section located downstream of the throttle valve connects with rising Temperature, the slide 63 is moved into a position in which the bias of the spring 31 ', so the restoring force of the measuring element 4 also increases

Claims (21)

Patent claims: 1. Kraflsloffcinsprit / .plant for geniischverdich · tcndc frcmdgczündctc internal combustion engines with continuous injection into the intake manifold, in which a measuring element and an arbitrarily actuatable throttle valve arranged one behind the other and the measuring element is moved against a restoring force according to the amount of air flowing through via an arbeilsglicd and thereby the moving part of a valve arranged in the fuel line for metering a Adjusted the amount of fuel proportional to the amount of air, characterized in that Hydraulic fluid serves as the restoring force, which is continuously and under constant, but arbitrarily changeable pressure through a pressure line promoted applied to the working link. 2. Fuel injection system according to claim 1, characterized in that the pressure of the liquid generating the restoring force through at least one pressure control valve (28, 68) controlled as a function of engine parameters is changeable. 3. Fuel injection system according to claim 2, characterized in that the pressure control valve (28, 68) is downstream of the working member (12) is arranged in the pressure line. 4. Fuel injection system according to one of claims 1 to 3, characterized in that the Working member (12) is coupled to the movable part of the valve designed as a flow divider valve (8). 5. Fuel injection system according to one of claims 1 to 4, characterized in that the working member (12) is designed as a piston which works in a cylinder bore (23), in the connection channel to the pressure line (22 e, lld, lic, Ua) towards a Throttle (23 a) is arranged. 6. Fuel injection system according to one of the preceding claims, characterized in that that the pressure brought about by the pressure control valve (28) is constant as a function of the pressure can be changed by the throttle valve position (7) 7. Fuel injection system according to one of claims 1 to S, characterized in that dei constant pressure caused by the pressure control valve (28) depending on the pressure downstream of the throttle valve (7) in the intake manifold (6 setting pressure can be changed. 8. Fuel injection system according to one of Claims 1 to 7, characterized in that the pressure control valve (28, 68) caused ai constant pressure depending on at least one temperature parameter (62, 78) can be changed (Fi g. 1 and 7, 8). 9. Fuel injection system according to one of Proverbs 6 to 8, characterized in that al Transmission element of the engine parameters on the pressure control valve (28) a cam (43 serves (Fig. 2). 10. Fuel injection system according to one of claims 6 to 8, characterized in that As a transfer element of the engine parameters at the pressure control valve (28) a space cam (32 serves (e.g. Fig. 1). 11. Fuel injection system according to claim ' characterized in that the motor core 209633/37 2490 greet with electrical quantities on the pressure control valve be transmitted. 12. Fuel tunnel injection system according to claim 1, characterized in that the point (24, 25) in the valve at which the injection quantity is metered , and the point (22 ft, 23α) at which the surface (13) of the working member (12) is acted upon, are connected in series in the direction of flow. 13. Fuel tank injection system according to claim 12, characterized in that a pressure reducing valve (52) at least in the form of a throttle (23 a) is connected between the places mentioned (Figs. 1 and 5). 14. Fuel injection system according to claim 5, characterized in that the working member (12) and movable part (12) of the flow divider valve (8) are formed in one piece as a control slide, the control slot via an annular groove (24) and in its bushing (23) arranged (25) metering the fuel, and its end face (13), which is acted upon by pressure fluid, is immersed in a space of particularly larger diameter (58) (FIG. 6) and is provided with a disk (57) which is almost the room diameter is as 15. Fuel injection system according to claim 14, characterized in that the spaces (58 a, 586) on both sides of the disc (57) are each connected to the fuel system via a throttle channel (23 a, 60). 16. Fuel injection system according to claim 1, characterized in that a flat seat valve is used as the pressure control valve (28, 68), in particular with a membrane (29, 71) as a movable one Valve part in which the bias of a spring (31, 72) loading the movable valve part in Can be changed depending on the engine parameters. 17. Fuel injection system according to claim 16, characterized in that both sides of the membrane (29) are under the same fuel pressure (F i g. 4). 18. Fuel injection system according to claim 1, characterized in that a temperature-dependent control element (62, 78) in addition to a pressure control valve (28, 68) has a closing element (63, 76) for a bypass (6) bypassing the throttle valve (7) of the intake manifold (6) 66, 75) is actuated and the bypass (66, 75) closes after the normal working temperature of the engine has been reached. 19. Fuel injection system according to claim 1, characterized in that the measuring element (4) is a disc which is fastened transversely to the flow direction at one end of a fixed and almost frictionlessly mounted pivot lever (18) and proportional to the through the suction pipe (3) The amount of air flowing is immersed in a corresponding section of the suction pipe that widens in a funnel shape in the direction of flow. 20. Fuel injection system according to claim 19, characterized in that the pivot lever (10) for transferring the deflection of the measuring element (4) directly on the moving part (12] of the flow divider valve (8) attacks 21. Fuel injection system according to claim 1, characterized! that the restoring force generating pressure of the liquid through a pressure control valve (28) controlled as a function of the throttle valve position (7) and the pressure in the suction pipe (6) downstream of the throttle valve (7) and by a par switched off as a function of a temperature parameter (78) controlled pressure control valve (68) is changeable (Fig. 1). For this purpose 2 sheets of drawings 249C