DE2135824A1 - ELECTRIC FUEL INJECTION DEVICE FOR COMBUSTION MACHINES WITH A THROTTLE FLAP IN THE SUCTION MANIFOLD AND WITH A FLAP FOR MEASURING THE AIR QUANTITY - Google Patents

Description

E. 429

Lr / Sz

Attachment to
Patent wa &

R 0 B iä HTB OSCH GMBH, Stuttgart

Έ ^} ~ P.? '± s.9h ·' · ■■ Jfo-'ftfIl stoff sinspritzei nrichtu np; for Bronnkraft ~ mascl-iijien with vainer in the suction pipe arif.-e arranged the pro π f. e! flap and with a he to measure air monpies in ^ serve the storage flap

The invention relates to an electrically controlled, preferably intermittently operating fuel injection device for Internal combustion engines with one arranged in their intake line Throttle valve and with at least one electromagnetically actuated internal injection valve - preferably with more than one injection valve on, one of which is assigned to a cylinder is - and ait oine-n for the Magxietinierungo \; ickluns of the valve in series power transistor as well as with a This preclio-locked transistor switch controls the synchronous to the crank shaft revolutions of the internal combustion engine

209885/0480

Robert Bosch GmbH R. 429 Lr / Sz

Stuttgart

switched on while simultaneously opening the injection valve and for a period of time that determines the respective injection quantity in this state during the discharge time of an electrical, is held as a capacitance or as an inductance energy storage device, which before each discharge process in is loaded in a defined manner.

A major advantage of such an electrically controlled Injectors consists in that during the intake stroke together with the intake air in each individual cylinder of the Internal combustion engine arriving amount of fuel very precisely the amount of air sucked in can be adjusted and that accordingly with good utilization of the performance of the internal combustion engine the setting can be made so that the exhaust gases in all load and speed ranges Contains a minimum of harmful components.

In known injection systems, the amount of air sucked in is not measured directly, but determined by the fact that an in Orientation behind the throttle valve connected to the intake pipe j inductive pressure sensor measures the intake air pressure prevailing there, with the respective air pressure values corresponding inductance of a pressure transducer to this. belonging iron choke the duration of the unstable operating state a control multi-vibrator is determined, which is triggered in a synchronous sequence to the Eurbelwelle revolutions. Because of the high speed-dependent flow resistances are relatively complex electronic switching devices in the known injection devices required, which for the ζ ah! dependent correction of the voia Intake manifold pressure sensor set to be injected before each work cycle Serve fuel quantity »

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209885/0 460

Robert Bosch GmbH R. 4-29

Stuttgart

It has already been proposed in an injection system of the type described at the outset, a substantial simplification of the control device which determines the duration of the opening pulses to achieve that in the intake line of the internal combustion engine a baffle plate serving as an air flow meter is arranged against a restoring force by the Intake air flow pivotable about an axis running on the edge of the intake cross section and with at least one on the Acting charging or discharging process of the energy store Means, in particular with the tapping of an adjustable resistor, is coupled, the baffle plate and the throttle valve of the internal combustion engine in the suction direction one behind the other lie.

In numerous designs of internal combustion engines, to improve the degree of filling, the intake paths are coordinated in such a way that rapid oscillations of the intake air flow can occur when the internal combustion engine is running in the middle and upper range. There is therefore a risk that the damper used for air volume absorption will take part in these vibrations and then display incorrect air volume values. This difficulty also arises when idling before all of four-cylinder four-stroke internal combustion engines, in which the crank engine is very well balanced and therefore enables a very low idle speed. The invention has for its object to prevent such vibrations on the one hand and on the other hand ensure a sufficiently high Arieprechempfindlichkeit dei ⁿ jam door to changes in Ansaagluftmenge. For this purpose, it is provided according to the invention that the flap is coupled to a pneumatic damping device.

209885/0460

Hobert Bosch GmbH R. 429 Lr / Sz

Stuttgart

Refinements and expedient developments result from those described below and shown in the drawing Embodiments.

It show: ₍

Fig. 1 is an electrically controlled, intermittently operating Fuel injection device with an air flow meter in its overview image and in partly schematic representation,

Fig. 2 is a schematic diagram of their electronic, the Control device determining the injection quantity,

3 shows a section of the intake line of the internal combustion engine according to Fig. 1 with the air flow meter and pneumatic damping device,

4 shows another air flow meter with a pneumatic Damping device,

Fig. 5 shows a modified embodiment of such Air flow meter,

6 shows an air flow meter with a load-dependent one Fuel enrichment,

Fig. 7 a Lxxftmen genmess he with one when opening the Throttle valve effective device for fuel enrichment when accelerating, and

8 shows a component for temperature-dependent change fuel enrichment for an air flow meter after Pig. 6th

The fuel injection system shown is for operation a four-cylinder four-stroke internal combustion engine 10 and determined comprises, as essential components, four electromagnetically actuated injection valves 11, those from a distributor

209885/0460 " ⁵ "

Robert Bosch GmbH R. 429

Stuttgart

The fuel to be injected via one pipe 13 each is supplied, an electric motor driven fuel feed pump 15 j a pressure regulator 16, the fuel pressure regulates to a constant value, as well as an electronic control device described in more detail below, which by one coupled to the camshaft I ^ of the internal combustion engine Signal generator 18 is triggered twice with each camshaft reversal, then one square-wave electrical each Opening pulse S for the injection valves 11 delivers. The time duration T. indicated in the drawing of the opening pulses determines the opening duration of the injection valves and consequently the amount of fuel that is used during the respective opening times from the interior of the under one practically constant fuel pressure from 2 atmospheric injectors 11 exits. The solenoid windings 19 of the injectors are each connected to a decoupling resistor 20 in series and to a common gain and Power stage 21 connected, the at least one at 22 Contains indicated power transistor, which with his Emitter-collector path in series with the decoupling resistors 20 and the magnet windings connected to ground on one side 19 is arranged.

In the case of gas-compressing internal combustion engines operating with spark ignition of the type shown is determined by the amount of intake air entering a cylinder during a single intake stroke the amount of fuel specified that can be completely burned during the subsequent work cycle. It is also important for good utilization of the internal combustion engine It is necessary that there is no significant excess of air after the work cycle. To get the stoichiometric you want To achieve the ratio between intake air and fuel is in the intake pipe 25 of the internal combustion engine in flow

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Robert Bosch GmbH R. 429 Lr / Sz

Stuttgart

direction behind their filter 26, but in front of their with a Accelerator pedal 27 adjustable throttle valve 28 an air flow meter Ii! provided, which consists essentially of a damper 30 and a variable resistor R, whose adjustable tap Jl coupled to the baffle plate is. The air flow meter LM works with a transistor switching device TS together, which supplies the control pulses S for the power stage 21 at its output.

The Trans is tor ehalt device according to its schematic diagram shown in Fig. 2 contains two each in ψ opposite operating state and for this purpose cross-fed back transistors, namely an input transistor T and an output transistor Tp and an energy store, which in the embodiment as a capacitor G, but could instead also be implemented as an inductance in a modified circuit. The duration of the respective / urgent unloading process results in the opening Gclauer T. of the injection valves. For this purpose, the storage capacitor G must be charged in a defined manner before each discharge process.

So that the unloading time already has the necessary in-. Formation about the amount of air allotted to the individual intake stroke, the charging is carried out by the one shown in the Embodiment in the form of the signal generator 18 reproduced charging switch that synchronizes with the crankshaft en \ iTi; rotations is actuated and causes the capacitor C -during itself over a fixed, constant Angle of rotation of the crankshaft extending charging pulse? LJ is connected to a charging source, which during this Each charging pulse delivers a charging current Yes. For the present case, it is assumed that the signal generator 18, which

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Robert Bosch GmbH R. 429 Lr / Sz

Stuttgart

in the practical implementation, consist of a bistable multivibrator, each of which is brought into its opposite operating position by the ignition pulses (not shown) can, closed over a crankshaft rotation angle of 180 ° and then opened over the same rotation angle is.

The arrangement according to FIG. 2 makes it possible to initiate the discharge process immediately after the charging process, which is terminated at 0, 360, 720 and so on . At the same time, the input transistor T-, which has been blocked since then, enters its current-conducting state, since as a result of the Sj> err \ mg of the output transistor Tp, a sufficient base current can now reach the base-emitter path of the input transistor via the collector resistor 35 and the coupling resistor 36. The charge stored during the charging process can then flow through the diode 37, which conducts current in this direction, and the collector-emitter path of the input transistor T _x During the discharge process, the voltage Uq across the capacitor C therefore drops linearly. After the discharge time T. that the output transistor Tp can again conduct current and thereby blocks the input transistor T. Since the diode 37 prevents the capacitor charging current from flowing through its collector resistor 39 when the input transistor T. is blocked, the next charging process takes place only then , if with the beginning of the next charging pulse LJ at a

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Robert Bosch GmbH E. 429 Lr / Sz

Stuttgart

Crankshaft rotation angle of 180 ° or 5 ^l i-0 ° the charging source A is switched on again.

At speeds n lower than 2,000 rpm, and at high load, the intake air flow shows strong pulsation. This can make the flap strong Performs oscillations around a central position, which corresponds to the actual temporal mean word of the air quantity Q-r does not correspond. To avoid such a mismatch, is in the embodiments described below of air flow meters a pneumatic JUirapfungseinrichtung provided, which on the one hand an "overshoot of the damper via its time average value of the intake air volume Prevents corresponding position addition, on the other hand, however, the flap quickly enough the respective Changes in the amount of intake air can follow.

In the air flow meter according to FIG. 3, the baffle flap 30 is fastened on an edge of the intake cross-section extending from the shaft 4-1, with which a radially protruding damping wing 42 is connected. This juxtaposes a cylindrical VJand 44 with a very small, but a defined leakage resulting in distance, which has a sectorforalge damping chamber ^ opposite that cavity iia suction pipe 25, which between dej? Storage flap 30 and the throttle valve 28 is located. A narrow DrosGelbohri ^ ng 4 G in the damper wing 42 ensures a permanent connection between the chamber 45 and this cavity in the arm pipe 25 In l'all a steady air flow in the suction pipe 25 prevails in the chamber 45 as a result of the droiL-sol Bohrunp: 46 a pressure p,. which is equal to the. Pressure ρ in (Um between the damper 30 and the throttle valve? 2ü lying hollow area of the intake pipe 25 · Since the effective area ϊ \ of the damper 30 is the same size as the effective area I ' _o des

* 45 wraps. The damper wing 42 limits this damping «- kammor _Q

209885/0460 ~ ^J "

BATH ORIGINAL

Robert Bosch GmbH R. 429

Stuttgart

Damping flight ice 42 is selected, causes a change in the Intake manifold pressure ρ no change in the damper position, because then the torques exerted on the damper shaft 41 cancel each other out. Only when the pressure p ^. in the damping chamber'4-5 follows the change in the intake manifold pressure, the baffle flap can move into its corresponding to the new intake manifold pressure Move position, with compensating air flowing through the throttle bore. Such a pressure equalization can, however with the pulsations described above, which have a frequency of 30 Hertz and more in a four-stroke VAerylinderbrenrikraf t machine do not take place quickly enough, so that the pressure fluctuations resulting from the pulsations have no effect stay on the flap. It can be done easily by a suitable choice of the bore diameter at the throttle point 46 achieve that that is caused, for example, when accelerating the internal combustion engine by opening the throttle valve Pressure rise is the pressure p ·. within a Tenth of a second to adapt to the changed intake manifold pressure able and allows the flap to get into its new position. The short one required for the acceleration enrichment The response time of the flap 30 is thus guaranteed.

In the embodiment according to FIG. 4, the shaft 41 is the Stowage flap 30 also connected to a .Attenuating wing 42, ■ which on its outer edge parallel to the shaft 41 with a small radial distance from the cylindrical part of a boundary wall 51 faces which a damping chamber 52 includes, which has a window 53 with the front of the storage flap lying inner roughness of the intake pipe is in connection the wall 5I is a defined throttle gap 54-, one of them just slow pressure compensation. between that with that Intake pipe interior connected, having a pressure Ρλ Part of the chamber and the one behind the cushioning wing 42

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Robert Bosch GmbH R. 429 Lr / Sz

Stuttgart

lying, a pressure Pp having part of the chamber 52 allows. In addition, a thin-walled bellows 55, which is connected to the space of the suction pipe located behind the damper flap 30, extends into the chamber. The bellows 55 acts as an elastic partition and has only low restoring forces. As long as the intake manifold pressure O _{x has} a constant value, the pressure p ^ = Pp. Then the damping vane 42 is ineffective. . ·

However, if the intake manifold pressure p ^ increases when pulsations occur composed of a constant pressure and a superimposed alternating pressure, the alternating pressure is transmitted via the soft rubber bellows 55 on the Kammerdruclc Pp, so that the Alternating pressure via the damping wing 42 is a compensating Torque exerts on the flap 30; this can then be at Appropriate choice of cashier and flights! Dimensions are not essential »Perform vibrations.

If, however, the throttle valve 28 is opened at the point of acceleration of the internal combustion engine, the two pressures p 1 and pp first drop so that no torque arises which counteracts the restoring torque M ^ originating from a return spring (not shown). Only through the slow adjustment of the pressure p _? on the pressure p ^, which takes place via the throttle gap 54, a fine torque can be effective on the damper. As a result, the damper flap 30 is also damped during acceleration. The amount of damping depends on the throttling effect at the throttle gap 54 and can be selected according to requirements.

2098 85/0460

Robert Bosch GmbH R. 429 Ir / Sz

Stuttgart

If ea should be required, the compensation for the. To make pulsating alternating pressures so strong that the damper JO in the transition!) he would follow the changes in the air intake of the internal combustion engine too slowly, this can be prevented by the fact that two, not shown, are under tension on the damping vane 42 Flutter valves are provided, one of which each locks against cieii pressure p _o and the andox'e locks against pressure p ».

A behavior that is equivalent in terms of functionality can be used with the Aue-fülmmgabobeispiel according to Fig. 5 can be achieved. there the dynamic counter-torque to the stowage flap is € 5 30 via a I'ioribrari 61 and an adjusting rod 62 on one with the damper shaft 41 connected adjusting lever 63 transferred. One two to membrane 65 takes over the function of the Guimrribalges 55 according to FIG. 4.

As in the previously described execution game, there is a slight decrease or increase in the pressure of the suction. Between the two membranes 61 and 65, there is a buffer volume over the vtragon, which is initially held up like a hard second spring. During the subsequent slow-axial adjustment of the pressure Pp to the outside air pressure, the damper 30 can follow the changed intake manifold pressure p ^. This compensation can be achieved by a sufficiently narrow throttle position; i) ^! \ .00 longöori that after a pulsation reverberation: ·.; '. J le "no chewing of pressure" can take place immediately and consequently the *. Pal ε, action s pressure olm «effect on the damper ^v j0 Just like in the variously described execution.vbuior.i el kaun vaivX 'in addition to the Dronsolstel! e ο in to both sides, ijüi., l'i oh gof; on cic-rx Ka] iM (; j *'. li 'uc k Pp and against the Außenluf tdruck wi t * ^ are pre .i'i above-.D ο ζ IN c-.tteivontil has DCTs a temperamental turliugigo Voj'.spojixiimg such tomporaturabhäiigigo advantages.

- 1? 209885/0 460

BATH ORIGINAL.

Robert Bosch GmbH E. 429

Stuttgart

voltage can be set in simple terms with the help of a bimetallic spring achieve, which causes the damping to decrease with falling temperature. Here there is one for him Operation of the internal combustion engine desired temperature-dependent transition enrichment- *

As already indicated above, the pulsations, which are undesirable in their effect on the baffle flap, are particularly strong when the internal combustion engine is operated at high volatility, ie when the throttle flap is fully or at least approximately fully open. In the example of FIG. 6, a compensation that becomes effective as a function of the load or the position of the throttle valve 28 is obtained. This exemplary embodiment differs from the deiajenipjcn according to FIG. Only in that the damping chamber 45 delimited by the damping wing 42 is connected via a return line 7-1 to the suction area 72 of the suction pipe 25, which is located behind the throttle valve 28 in the alignment. In the immediate vicinity of the chamber 45, a throttle point 73 is arranged in the course of the return line. In front of the "ignition" of the return line i; i the suction chamber 72 there is a valve device 755, the valve plate 76 of which hangs on a tension spring 7 and is brought into its closed position against the tension of this spring by the negative pressure prevailing in the suction chamber 72, when the suction pressure in the suction chamber 72 falls below a specified value. The return line 71 is only opened when this minimum value is exceeded when the pipe pressure rises.

In the embodiment according to FIG. 7, measures are taken the one transitional enrichment for the fuel air mixture cause the internal combustion engine and ensure that when sudden opening of the throttle to achieve a rapid During the acceleration process, the flap is deflected more strongly

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BATH ORIGINAL

Robert Bosch GmbH, R. 429 Lr / Sz

Stuttgart

than it corresponds to the current air flow. With the The damping chamber 45 located behind the damping wing 42 is a bore 80 in communication which leads to an auxiliary chamber 81 leads, which is closed by a membrane 82. In the center of the membrane there is a reinforcement disc 83, which is articulated to one of the two arms of a lever 84. The other arm of this lever is via a rod 85 with the Arm 81 of the throttle valve 28 is coupled. If to accelerate the internal combustion engine, the throttle valve in the indicated arrow direction counterclockwise is, pulls the two-armed lever 84 in the direction of the arrow Membrane to the outside and generates practically without time delay in the chamber 45 a negative pressure, which over the damping wing 42 deflects the flap 30 more than it corresponds to the amount of intake air growing slowly at the beginning of the acceleration process. The throttle bore 46 in the damping wing ensures that the resulting Fuel enrichment lasts only a short time, namely until the negative pressure generated by the membrane 82 is equalized to the pressure in the intake pipe via the throttle bore 46 Has. So that the additional chamber can only be effective when the throttle valve 28 is rotated in the opening direction the connecting bore 45 through one of a leaf spring 87 loaded plate valve 88 closed, which has a central compensating bore 89. This allows for a closing movement the throttle valve only a little additional air from the additional chamber 76 into the damping chamber 45, what As a result, it is not possible to influence the position of the baffle flap 30 during the closing movement.

The arrangement shown in FIG. 6 can be used to achieve a temperature-dependent corrector according to FIG. 8 also in the Way can be modified that the return line 71 ia, a

; 209885/0460

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ORIGINAL INSPECTED

Robert Bosch GmbH R. 4-29 Lr / Sz

Stuttgart

Valve housing 91 is initiated, the connecting bore 92 to the suction chamber 72 located behind the throttle valve 28 leads and through a valve cone 93, which is seated on a bimetal spring 94 · narrows or widens as a function of the temperature can be. Instead of a bimetal spring 94- can also be a Expansion element 95 may be provided.

By suitable choice of the connection point of the return line. 71 to the chamber 4-5 can / affecting the influence of the load dependence in "the desired V else The advantage of these arrangements is that the deflection of the 'stowage flap 30 takes place only by means of pressure effects and therefore no mechanical influence members, mainly. no lever linkage and the like are necessary, which would cause additional friction.

209885/0460

Claims (12)

- Ip - Robert Bosch GmI) H R. 429 Lr / Sz Stuttgart claims 1.) Electrically controlled, preferably intermittently operating fuel injection device for internal combustion engines with a throttle valve arranged in its intake line and with at least one electromagnetically actuated. Injection valve - preferably with several injection valves, each of which is assigned to one of the cylinders - and with a: -: The magnetizing winding of the valve in series with a power transistor fiov'ic with an upstream iDransistor cha 11 device that synchronizes with the crankshaft revolutions The internal combustion engine is switched on while the injection valve is opened at the same time and is kept in this state for a period determined by the respective Einyprit ^ iiienge before the discharge time of an electrical energy storage device designed as a capacitance or as an inductance, which is charged ^{in a defined V. 7 before each discharge process} is, as well as with an arranged in the intake line of the internal combustion engine, as Luf Imcii - {_: γ: 3ϊϊλ '· ■ · £ ■>.' γ serving flap, which is pivotable against a restoring force and an axis running on the band of the intake transverse solmitea with at least one on the loading and / or unloading front input of the energy storage - 16 20988B / 0A60 BAD OFUQSNAL Robert Bosch GmbH E. 429 Stuttgart acting means, in particular with the tap of an adjustable Resistance is coupled, whereby the »storage flap and the throttle valve of the internal combustion engine one behind the other lie, thereby gekermseichnet that the flap coupled with a pneumatic damping device is. 2. Device according to claim 1, characterized in that a damping wing (42) is coupled to the shaft of the damper (30) and faces the walls of a damping ungskanimer (45) with a small gap, which in the pivoting range of the damping wing as a cylinder el: tor is trained. 3 · Device according to claim 2, characterized in that the damping chamber (45) with a dome behind the »storage flap (JO) lying suction chamber connected and by the damping; '- wing (42) is delimited from this »suction space. 4. Device according to claim 2, characterized-characterized; that the damping ungfikanuner a section (52) on v / eist against the air tstrttmimgszrLclrbung behind the flap (30) lying »Saugraun dir.-eh elastic partitions, in particular one Bellows (55) »is sealed, whereas the one on the other sixth of the Düi-mfurigc- - 17 209885 / OA60 BAD ORfGlMAL Robert Bosch GmbH R. 429 Lr / Sz Stuttgart flügelis (42) lying part of the damping chamber with the the suction chamber located in front of the damper is connected, 5. Device according to claims 2 to 4, characterized in that that the damper vane (420 contains a throttle bore (46). 6. Device according to claim 5, characterized in that the throttle bore (46) through a spring-loaded valve body, in particular a flat valve disk is sealed. 7. Device according to claim 6, characterized in that ■ that two spring-loaded valve bodies are provided, one of which each against a different side of the damper blade seals. 8. Device according to one of claims 2 to 7 »characterized in that the _{area of the flap (50) exposed to your intake manifold pressure (p CT} ) is at least approximately the same size as the area of the damping flight (42). 9. Device according to claim 1, characterized in that with the storage flap (30) or the storage flap shaft (41) an adjusting lever (62, 6 $) is coupled with a - 18 209885/0 460 - Xo - Robert Bosch GmbH R. 429 Stuttgart first membrane (61) is connected, which has a compensating bore (64) contains and delimits a space that is separated from the suction space behind the flap by a membrane (65) is separated. 10. Device according to one of claims 2 to 8, characterized in that that from the chamber (45) to the suction chamber (72) located behind the throttle valve a line (71) ™, in which a valve device (75-77 or 91) that closes depending on the intake manifold pressure is arranged. 11. Device according to claim 10, characterized in that the valve device (91) is variable as a function of temperature Contains connection opening (92) to the suction chamber (72). ■ H 12. Device according to one of claims 2 to 8, characterized in that that the chamber (45) with the interior (81) a pressure cell is connected, the elastic membrane (82) with the throttle valve. (28) - preferably via a lever linkage (84, 85, 86) - is connected in such a way that when the throttle valve is opened an enlargement of the interior (81) and consequently 'a pressure reduction in the chamber (45) results. - 19 209885/0460 Robert Bosch GmbH ■ R. 4-29 Stuttgart IJ. Device according to claim 12, characterized in that a constantly open throttle point (89) is provided between the chamber (4-5) and the interior space (81). 14. Device according to claim 12 or 13, characterized in that the connecting line (80) between the chamber (4 5) and the interior space (81) a valve (83) is provided is, dar; opens when there is negative pressure in the interior. 209885 / 0A60 Blank page