DE2062067C3 - Control device for operating a mixture-compressing internal combustion engine working with exhaust gas recirculation - Google Patents

Description

The invention relates to a control device for operating a mixture-compressing, with exhaust gas recirculation working internal combustion engine, the intake pipe of which an adjusting device comprising a throttle valve and is connected to the exhaust line via a return line. which with equipped with an electromagnetically controlled shut-off valve. the shut-off valve at partial load operation the machine is in an open position, while it is closed when idling and is controlled during operation at full load so that maximum power is delivered.

According to I IS A. Patent 3 204 621, a shut-off valve operated by a pneumatic actuator is provided, the associated return line of which opens into the intake manifold behind the throttle valve in the intake pipe of the internal combustion engine and, due to the pressure ratios, recirculates an amount of exhaust gas that increases with decreasing air flow. AK StelHrafi for actuating the shut-off valve is used there the pressure prevailing downstream of the throttle valve and / vr 7üidvcistelhmg exploited vacuum. At full load, the shut-off valve cannot be completely closed, and consequently the known control device can

C ₁ ") the maximum machine performance - although aimed - not fully achieved.

Ali the nSA.-Patcntscli: il't 2 -K ^l> W4 is a Abuasriickführeinrichtiiiu! known, the Abcasrück-

filling line can comprise an electromagnetically actuated baffle plate or baffle flap,

contains shut-off valve and in the suction direction behind which depending on the amount of suction air

Throttle valve and a carburetor in the intake air is adjusted directly by the intake air

tuns joins. The shut-off valve can only then be used for this purpose, depending on

ucopened when three nut of the magnet winding 5 of the degree of deflection operating variables of the

iune of the shut-off valve lying switches in the internal combustion engine, for example the one per work on

are in their closed position, one of which wants the amount of fuel to be injected or the ignition

can be operated manually, a second one with the setting angle, the given operating conditions

The accelerator pedal is coupled and adjusted when the accelerator is opened.

and the third contact with the brake pedal ae- io In this sense, the is coupled and only then in the closed position invention at least one of the switches with the is located as long as the brake pedal is not depressed. Throttle valve and / or with a baffle vcr-Der In contrast, the invention is bound to the task, provided a baffle plate for the combustion base, the Steuerereinrichtuni; to train / that engine is provided. In further form the shut-off valve can only be used during partial load operation of the X5 device of the invention, the switches in the basic circuit Machine is in the fully open position and there- a transistor be arranged, the bmitterher in the partial load range the mixing ratio between the collector section in series with the excitation winding see fresh air and recirculated exhaust gases condensing the electromagnetic device to operate -tant can be kept "so that" the rest of the shut-off valve lies, with the device entlose Combustion of the injected fuel is not required either directly on the shut-off valve Fresh air does not act in an undesired outward or opening sense or in addition measure is replaced by recirculated exhaust gases. serves, with the interposition of a magnetic.!. From French patent specification 1 174 571 and hydraulic or pneumatic Stellkratt the AD-der French patent specification 925 308 it is to be operated with a shut-off valve.

Exhaust gas recirculation working mixture compression * 5 In a preferred embodiment of the hriinlon Internal combustion engines known, the return line is one of the two switches during the uing upstream of the throttle in the intake idle and the other switch during the touch to flow into. Since there each carburetor drove the internal combustion engine under full or on- and a load that is almost full of the flow in the closed position the air or an already heated 30 hold. In this case, both switches can be switched on each Fuel-air mixture dependent pressure reduction one of your switching contacts with the emitter of the affects the amount of recirculated exhaust gas can be connected to the above-mentioned transistor, but in these Control devices, however, the mixing ratio rem second switching contact - preferably . Do not wipe fresh air and exhaust gases carried back via a diode each - at the tap on one above the be kept constant. '35 Operating voltage of the transistor, out In order to solve this problem, at least two resistances are formed in a cutting direction of the type described at the beginning of the invention divider to be connected, with the provided in accordance with that the machine has an injection voltage divider also the base of the transistor internal combustion engine and the Rückrücklcitune is connected.

Ansausrichtung before the throttle valve in the intake 4 ° other refinements and appropriate pipe opens that with the adjusting device two developments of the invention result from the electrical switch are coupled, of which the one described below and the first in the drawing read only during idle operation from the Execution items shown. It shows
Adjusting device in one of its two switching positions. 1 one with intake manifold gasoline injection is kept poor, the other, however, only with a fully healing internal combustion engine in the plan view of]: is or approximately Yoll. Is in one of its two above and in a highly schematic representation,
Switch positions is held, and that the switch F 1 c. 2 a control device for automatic cooperate with the shut-off valve in such a way that switching on and off the shut-off valve in the Brennkrafimadas only then in its closed position machine of FIG. 1 exhaust gas recirculation used, is retained when either idling or 50 L i g. 3 a second, with electrically controlled suction full-load or almost full-load operation prevails, but rohreinpritmng working internal combustion engine with is fully open at part load operation. anemical air volume measurement.

The mechanical Kimphinii of the two electric The 4-cylinder \ lertakt- shown in Fig. 1

see switches with the StellvonichHine and the con- internal combustion engine IO is electromagnetic with four

The smiküve design of these switches does not allow any useful injection valves to be equipped by

lci trouble. ' The invention arranges each one on the / u the individual / yhn-

Now, however, the switch has the advantage. your engine driving Vcr / further

therefor sizes / ranges' idle and full load or anlumgsstut / s of the intake pipe 12 is arranged. m

approaching full load, in which no exhaust gas recirculation intake pipe, a throttle valve 13 is rotatably loaded

should take place, are exactly delinierhar. ⁶ ° device. which with an accelerator pedal 14 from its l.eer-

The expression »adjusting device can in the sense:; · ιιΙV.eUiin;. · Optionally be pivoted so far

of the invention, for example, with one that the running internal combustion engine at Bc-

Normally designed throttle valve adjustable by the accelerator pedal drove the greatest possible amount of air under full load

include, which in the intake pipe of the Bivnnkrafima- via the air filter upstream of the intake pipe 12

v-chinc is arranged and is capable of sucking in while the combustion engine is running. With every crankshaft

maschine'die quantity of air drawn in is determined, without the internal combustion engine turning, the

Injection valves are even influenced by this in their position. which the nail substance to be injected

On the other hand, this expression is also intended to mean over pipelines, not shown, under one

constant pressure of 2 atü is supplied, opened by rectangular, electrical impulses, which are supplied by an electronic control unit 17.

The control unit 17 contains in the usual way a monostable multivibrator, which by one with the Crankshaft 18 coupled signal generator, not shown, is triggered and the opening period and consequently the amount of force exiting the injection valves is determined. The adaptation of the respective Injection quantity is carried out by known means, not shown. The goal of such an adjustment is to achieve complete combustion of the injected fuel on the one hand and on the other hand to provide the maximum possible power of the internal combustion engine when operating under full load be able. The combustion exhaust gases leave the internal combustion engine via the exhaust line 19, the into an exhaust pipe used for soundproofing 20 joins. From there the exhaust gases reach the outside via a pipe socket 21.

About the proportion of harmful ingredients To be kept small in the combustion exhaust gases, a small amount of the exhaust gas is over a return line 25 from the exhaust line 19 into the suction line 12 in the suction direction before Throttle valve 13 added. Such an exhaust gas recirculation would occur when the internal combustion engine is idling affect their smoothness and do not achieve maximum performance when operating under full load leave.

In order to avoid these disadvantages of exhaust gas recirculation, the accelerator pedal 14 and the as Actuator acting throttle valve 13 of the internal combustion engine two switches 27 and 28 coupled, of which the first switch 27, a movable switching arm 31 and a fixed counter-contact 32 contains, is only closed if and as long as the throttle valve 13 is in the idle position is located. The second switch 28, a movable switching arm 33 and one with this cooperating, fixed epee contact 34 is closed only when the Throttle valve 13 when the internal combustion engine is running under full load or at least completely is approximately in its open position, in which it gives the intake air the largest possible passage cross-section releases.

The switches 27 and 28 belong to a control device with which a in the exhaust gas recirculation line 25 arranged shut-off valve 35 can be opened. The shut-off valve contains a shut-off valve 36, which with the help of an electromagnet 37 from the illustrated Spcrrrstellung in the open position can be brought when the electromagnet with the help of the following described in more detail, electrical control device is excited.

The control device is shown in its electrical schematic in FIG. 2 reproduced and contains next to the two switches 27 and 28 a transistor 40 of the npn type controllable by these switches, the one with its limit on a limiting resistance 41 is connected to a common negative line 42. those with earth in connection stone And also at the negative pole of a high-voltage trainer for the operation of the niclii shown Brennkiaftinaschinc serving battery liegl. the Emii'er-Kollcktor-Streckc of the transistor 40 licct with the excitation winding, not shown in detail, of the electromagnet 37 in series on the common, positive lead 44 connected to the positive pole of the battery, the winding of the electromagnet to suppress voltage peaks that occur when the electromagnet is switched off is bridged by the series connection of a resistor 43 and a quenching diode 45.

The switching arms 31 and 33 of the two switches 27

ίο and 28 are over the negative line 42 with the E ^ mitfer of transistor 40 connected. Your fixed mating contacts 32 and 34 are connected to tap 47 of the voltage divider described in more detail below and connected by one of two diodes 48 and 49 decoupled from one another. As a result of this decoupling it is possible to use the switches over the influence of the control device and the shut-off valve 35 also other control processes that are important for the operation of the internal combustion engine, for example, an increase in the amount of fuel at full load or a shutdown in overrun mode to accomplish.

The voltage divider contains a first divider resistor 50 and connected to the positive line 44

5 a second divisor resistance 51. the one with the minus termination 42 is connected and to his other End 52 is connected to the base of transistor 40 and the cathode of a diode 53. Dip Diode 53 is in series with a third divider resistor 54, which is connected to voltage divider tap 47 connected.

As long as the two switches 27 and 28 are open and the internal combustion engine is therefore neither in If no load is still operated under full load, the transistor 40 receives via the two divider resistors 50 and 54 and through the diode 53 a sufficiently large base current and can then the Energize electromagnet 37 with its collector current, so that this the shut-off valve 36 of the shut-off valve 35 can be brought into the open position and resound there. If one of the two switches 27 and 28 is closed, the tap 47 of the voltage divider reaches almost negative potential, whereby the Transistor 40 is blocked, the electromagnet 37 is switched off and the shut-off valve 35 in its Closed position is brought. To protect the transistor 40 against overload is in the event that on Electromagnet 37 a short circuit occurs between the base of transistor 40 and negative lead 42

the series connection of two diodes 56 and 57 is provided. These form the base-emitter section of the transistor 40 and the limiting resistor 41 existing branch a parallel current path, the one in the same direction as that

Base emitter line is current-carrying.

In the case of the second exemplary embodiment in FIG Internal combustion engine 10 shown here is also provided with a suction pipe fuel injection. the Einsprii / Ycnlilc 1Ϊ are each via a fuel line

61 connected to a fuel valve 62, in which the fuel from an electric motor driven pump 63 and one of the pumps nachgcschaltctcn pressure regulator 64 on a constant Value is kept around ciwa 2 atm. As with

The training example described above is one Exhaust gas recirculation line 25 is provided, which has a an Iüektioinapneicn 37 actuatable shut-off valve 35 contains.

Io

"End of the ^ ^^ enen Au, -führungbe.sp.el is the Brenntraftmascl ™ ^e ™ ™

the combustion engine is arranged such that they are in opposition to the force of a not ^represent f ^ '' ^th return spring to "more urn J ^ Ach * 67 ve" pivots, the greater the in the ^ 'teintot of α "internal combustion engine ^ sucked air quantity of the so-called air throughput .st M. of the damper 65 and its shaft 67, the tap 68 is an ^ e.ner

held constant ° »Ϊ« Α ^^ Α antentiometers 69 coupled the one, exponenueu a

has a rising course and therefore ηm. ^ m Lutt

by salt ^at least? ^{ah e} ^ J'X _n ^a SSte control voltage for the speed synchronous triggered control unit 17 of the Einspntzan ^ »efert.

Moreover, with the storage flaps contraction em Betat, gungsarm 72 lter for e.nen first saddle ^ 73 un a second switch 74 connected to the pivot arm 7Z leaves the switch 73 is closed as long as: the throttle valve 13 ir their Schheßlage. Far * ™ ^ course of the Brennkraftmaschme bcfmdet ™ ^{d only} ° J _n

nig intake air in the ^br 5 "^ _c ^"! He leaves that the stowage flap 65 is only a ^ cnn ^ upg ^ m.

with full lines ^w ^ ^r | ^ _s ⁿ ™ _k * hestosition is deflected As soon as the deflection of the stank flap becomes larger ^ and ^then ^ " ^er ^ drawing ^ interpreted W. ^ kel" i

becomes, he gets to the S *?. ^ ' ⁷ fn wldTeV his arm 75 in his; SüilieBsteUung rather touching in we ■ a mating contact 76th This ScW.eßs ^ eM.ng D

holds switch 73 like this ^ J ^ * ^ "" " machine neither m den I ^ arfOTrucktehrt

If the »sucked in ^L ^ ™ ^ _f S d | _r ⁸ _Dros ! derDreh ^ l ^ erdurAw ^^ fnungfl

selklappe 13 is increased, rotates the MaU ter decrease desiWinkeh '^^

| ^Ch h _t i ^a s "h ⁷ _ß e _g ^ W ge

Send Schfl a m78 moves and this closes

_{Load is operated and the one} for this operating case

the applicable angle _{2 of} the flap 65 below

is ^ ^ ^ ^ _{exhaust gas} _ _recirc .

_rungsleitun g 25 should be opened only as long as ^^^^ _{not Lecrlauf and} not _located ^ _{g in the F} j _{2 n again.}

un _{control device} using the

gq, ^ _{n working switches} 73 and 74

It must be _modified that the two

Schaher 73 and 74 arranged in series to each other ^^ ^ _{the voltage divider from} -

on the other hand are connected to the positive line 44. The transistor 40 can be opened currentle.tend ^ ^ _Abs ^ _rventjl , so-

S _{spectators are closed} . _Wen n however

g ^ _{{net wjrd (comes} ^ ₁ ,

_{tand g0 to effect> which one in a} fold ^^ ^^ _{that then the gm T}

The _{effective base} voltage, which is tapped off at the contact point 52, is no longer in the _{direction of>} ^{P in} _order to keep the transistor conducting. The a ₅ electromagnet 37 can then return the locking _{flap of} the Ab ent £ _{35 to its closed position}

Instead of the in the drawing in F i g. 3 envisaged _viewers “ _{and 74 one can} also

Provide electronic switches that are _{designed and used as} threshold switches in a known manner

with the adjustment path of the baffle flap 65 an- ^ ^ _{between the f}

potentiometer 69 and its tap 68 a

represents, be connected. Such threshold value- 8 ^^ ^ _{a] s integrated switching auP} .

~ be formed, whereby it is easily possible to st, ζυ-g _n ^ ^ _control device electronic

_{Assemblies of the} control device 17 - for example, dessin multivibrator, intermediate amplifier Multiph ornamental stage .dgl. - to be included in this integrated circuit.

1 sheet of drawings

Claims (10)

Patent claims: 1. Control device for operating a mixture-compressing, working with exhaust gas recirculation Internal combustion engine, the intake pipe of which has an adjusting device comprising a throttle valve and is connected to the exhaust line via a return line, which is equipped with an electromagnetically controlled shut-off valve, the shut-off valve When the machine is operating at part load, it is in an open position, but when it is idling is closed and is controlled during operation at full load so that maximum power is delivered is, characterized in that the engine is an injection internal combustion engine and the return line (25) in the suction direction before the throttle valve (13) opens into the intake pipe (12) that with the adjusting device (13 or 65) two electrical switches (27, 28 or 73, 74) are coupled, of which the first (27 or 73) only during idle operation by the adjusting device (13, 65) in one of its two switch positions is held, the other (28 or 74), however, only at Full load or almost full load is held in one of its two switching positions, and that the switches interact with the shut-off valve (35) in such a way that the shut-off valve only is then held in its closed position when either idling or full load or there is almost full load operation, but is fully open during partial load operation. 2. Device according to claim 1, characterized in that that at least one of the switches (27, 28) with the throttle valve (13) or with the throttle valve connected accelerator pedal (14) is coupled. 3. Device according to claim 1, characterized in that at least one of the switches (73, 74) with a baffle plate (65) belonging to the adjusting device, in particular a baffle flap connect is. 4. Finrichtung according to any one of claims 1 to 3, characterized in that the switch are arranged in the base circuit of a transistor (40), the emitter-collector strccke of which in series with the excitation winding of the electromagnetic device (37), which is used to actuate the shut-off valve (35) is used. 5. Device according to claim 4, characterized in that one of the two switches (27) during idling and the other switch (28) during operation of the internal combustion engine is held in the closed position under full or near full load and that both Switches connected to one of their switching contacts (31, 33) with the emitter of the transistor (40), with their second switching contact (32, 34), however - preferably via a diode (48 or 49) - to the tap (47) of one lying above the operating voltage of the transistor at least two resistors (50, 51) formed voltage divider are connected, with which also connected to the base of the TrunvMors is. 6. Finrichtung according to claim 5, characterized in that between the Aburiff (47) of the Voltage divider and the connection point (52; the base of the transistor (40) a series circuit from a third voltage divider resistor (54) and a diode (53). 7. Device according to claim 5 or 6, characterized in that between one with the two switches (27, 28) connected - preferably connected to ground - operating power line (42) and the emitter of the transistor (40) a limiting resistor (41] is provided and that between the base of the The transistor and the operating current line are a series circuit of at least two diodes (56, 57), the one from the base-emitter path of the transistor (40) and the limiting resistor existing branch form a parallel current path, which is current-permeable in the same direction as this. 8. Device according to claim 3, characterized in that the return line (25) between the throttle valve (13) and the baffle plate or baffle flap (65) in the intake pipe (66) joins. 9. Device according to claim 3, characterized in that that the baffle plate or baffle valve (65) in the suction direction in front of the throttle valve (13) is arranged and that the return line (25) in the suction direction in front of the baffle plate or damper (65) opens into the suction pipe (66). 10. Device according to claim 1, characterized in that the tap (68) of a potentiometer (69) is coupled to the actuator (13, 65) and that the tapped voltage (U) is fed to an electronic threshold switch.