DE2411874A1 - FUEL CARBURETOR WITH CONTROL DEVICE FOR A COMBUSTION ENGINE - Google Patents

Description

The invention relates to a fuel metering device for an internal combustion engine, with an intake duct with a mixing duct arranged therein, in which depending on A reduced first pressure is generated therein flowing through air, which in connection with a relatively high second pressure is used to meter the amount of fuel flowing into the intake duct.

Due to recently issued regulations on the reduction of pollutant emissions in engine exhaust gases and the automotive industry in general is increasingly demanding the use of very expensive and complicated fuel metering devices into consideration, including fuel injectors in various forms. this happens on the assumption that such injectors alone are made dependent on various engine operating parameters can then be made according to such operating parameters

4098U / 0269

/ 2

- 2 - 43 919

the air-fuel ratio in that supplied to the engine To change mixture.

The invention is based on the object of creating a device which very precisely controls the fuel flow rate to assign a very precise value and depending on different atmospheric conditions, such as pressure, Temperature and the like., As well as engine operating parameters, and in particular such a device to improve in a carburetor engine.

This task is erfindungsgamäß with a carburetor for one Internal combustion engine solved, which has an intake duct with an air inlet at one end and an outlet at the other end, a fuel supply and metering device with a Fuel source and the intake duct is in communication, and a by-air device hereinafter referred to as the "dry system" has that for changing the fuel flow rate at the metering device, the pressure difference across this is able to vary.

Further embodiments and advantages of the invention emerge from the following description and the claims.

The invention is explained below with the aid of schematic drawings of several exemplary embodiments with further details explained. In the drawing shows:

1 shows a simplified representation of an internal combustion engine with a carburetor according to the invention,

2 shows a side view in section of a carburetor according to the invention with an adjustable mixing channel,

/ 3 409844/0269

- 3 - 43 919

Pig. 3 shows a diagram of the dependency on the mixing channel negative pressure and air flow rate,

4 shows a diagram of the dependency on the fuel-air ratio , with the fuel in English. Pounds and air in engl. Cubic feet are indicated, and Air flow rate in English Cubic feet,

5 shows a diagram of the dependence on the fuel-air ratio, for the fuel in English. Pounds and air in engl. Pounds are indicated, and air flow rate ,

6 shows a side view in section of a carburetor according to the invention with a non-adjustable mixing channel, and

7 shows a simplified representation to explain the inventive concept implemented in a metering device.

Fig. 1, which is partly schematic, partly carried out in simplified outline, shows a briefly referred to below as a motor Internal combustion engine 10 with an intake manifold 12, on the top of which a carburetor 14 is mounted, with a multi-stage power transmission device or a multi-stage transmission 16 and an exhaust system 18, which consists of a Exhaust manifold 20, exhaust pipe parts 22, 24 and 26 and in these reduction and oxidation reactors arranged one behind the other 28 or 30 is composed. With the exhaust pipe part 22, an oxygen sensor and transducer 32 may be associated. An engine speed sensor and transducer 34 can be driven via any transmission device 36.

/ 4 409844/0269

- 4 - 43 919

2 ^ 17874

The carburetor 14 shown in Fig. 2 has a main part or housing 38 in which an intake duct 40 is formed which has an air inlet side 42 and an outlet or discharge side 44. The outlet side 44 leads to an Eirlöis an interior space 48 of the intake manifold 12 of the connected engine 10. One is in its position in the intake duct Variable throttle valve 50, which is rotatably connected to a throttle valve shaft 52 for pivoting, for example and the working medium or combustible mixture flowing from the intake port 40 into the intake port 48 of the intake manifold 12 able to regulate. In general, such a combustible mixture is of course composed of on the inlet side 42 incoming atmospheric air and the intake duct 40 from a connected fuel tank or Fuel float chamber 54 supplied fuel.

In the example shown, the fuel float chamber has a corresponding vessel or housing 56 in which a Float 58 can be arranged, which is a known (not shown) fuel inlet float needle valve, which is connected to the float chamber, controls so that the level of the fuel 60 contained in the housing 56 is maintained at a predetermined height 62.

As can be seen from the drawing, an adjustable mixing channel can have a mixing plate whose position can be changed have, which can be fixedly connected with fastening means 66 and 68 to an internally arranged arm 70, the in turn to a rotatably mounted in the housing 38 rotatable Shaft 72 is firmly connected. The mixing channel can be designed so that it, when viewed according to the with a Direction indicated by arrow 74, at the narrowest point of the adjustable mixing channel an essentially rectangular opening limited. Indeed, opposing walls, one of which is designated 76, may be flat planar Form areas between which those in their position

409844/0269 Λ

- 5 - 43 919

changeable or adjustable mixing plate 64 about the center line or axis of the rod or shaft 72 with little play is pivotable. These flat or planar surfaces preferably end at a boundary line 78, starting from which the in the flow direction adjoining section of the intake duct 40 gradually changes in its configuration until it is circular in order to accommodate a substantially circular throttle valve 50 in the appropriate case.

A second lever 80, which is arranged essentially outside of the housing 38, is connected to the shaft 72 in a rotationally fixed manner can be, and whose pivotable arm is connected to a ■ connecting rod 82,84. The connecting rod 84 is Part of a damping device 86 which, in the example shown, has a cylindrical inner chamber 88 which has a corresponding Flud and a sliding piston 90 contains. The connecting rod 84 penetrates the piston 90 with play and rests against it with its lower part 92. One too Compression spring 94 accommodated in the inner chamber 88 urges the piston 90 continuously and elastically downwards. To the exit To prevent damping flow from the inner chamber 88, a corresponding seal 96 can be provided. at Adjusting the piston 90 with the connecting rod 84 upwards, that located in the inner chamber 88 above the piston 90 becomes Fluid is generally displaced into an area below piston 90. This can be done via the piston 90 Exactly dimensioned relief devices 98 or with any equivalent means known per se happen.

A lever 100 connected in a rotationally fixed manner to the throttle valve shaft 52 is operatively connected to a movement transmission linkage 102 connected, which leads, for example, to the accelerator pedal 103 of the vehicle operated by the driver, so that when adjusting the connecting rod or transmission rod in the direction indicated by an arrow 104

409844/0269 / 6

- 6 - ■ 43 919

the throttle valve 50 about the center line or axis of the Throttle valve shaft 52 is moved in the counterclockwise direction in the opening direction.

A second lever 106, which is arranged on the throttle valve shaft 52 so as to be rotatable about the same, can be pivoted with an arm 108 connected to the connecting rod 82. The levers and 106 in turn have arms 110 and 112, which are in bear substantially in the transverse direction extending contact or stop elements 114 and 116. One with its main turn The spiral spring 118 wrapping around the throttle valve shaft 52 is operationally with its Legs 120 and 122 on lever arms 110 and 112, respectively and thereby normally holds the stop members 114 and 116 elastically in contact with one another, which leads to a common movement of the levers 100 and 106.

A corresponding level air or ventilation duct 124 has a first end 126 associated with a corresponding source of atmospheric pressure or any such source atmospheric pressure source and with its other End with an interior space 140 in the housing 56 of the fuel float chamber in connection.

In the example shown, a fuel supply and - Metering device preferably a channel or a line 130, which is connected with an opening 132 to the housing 56 of the fuel float chamber, as well as a second fuel supply line arranged essentially in the transverse direction 134 with one end I38 to the intake port 40 preferably at a neck or the narrowest point 136 of a non-adjustable mixing channel section in the direction of flow 137 downstream body is connected.

One present in the fuel supply line 134, exactly dimensioned passage or opening 142 can be formed with a corresponding profile that it is with a

409844/0269 / 7

- 7 - 43 919

profiled metering element 144 of a needle-like closure member 146 cooperates, with a pivot or pivot pin 148 in a recess 150 of the adjustable Mixing plate 64 can be pivotably connected to this.

The operation of the carburetor 14 is essentially as follows. It is assumed that the connected or associated The engine is running. When adjusting the accelerator pedal 103 about a pivot bearing 105 counterclockwise becomes the transmission linkage 102 moves to the right and causes pivoting of levers 100 and 106, throttle shaft 52 and throttle valve 50 around the axis of the throttle valve shaft 52 protrudes substantially counterclockwise in the direction of opening of the throttle valve. This adjustment or movement in the opening direction is carried out via the connecting rod which interacts with the aforementioned components 82 transferred to the lever 80, which about the axis of the shaft 72 substantially counterclockwise pivots and corresponding movement of the lever 70 and the adjustable mixing plate 64 causes.

With this pivoting of the lever 80 in the counterclockwise direction the stem or connecting rod 84 moves the damping piston 90 through the fluid in the chamber 88 upwards and forces it to poke through the precisely dimensioned channels 98. If the swivel amount of the Lever 100 a predetermined amount, the resistance counteracting the flow of the fluid in the channels 98 is sufficient from decelerating or slowing down the speed of the upward movement of the piston 90 so far, that the actual amount of pivoting of the lever 80 and the adjustable mixing plate 64 is less than the amount of pivoting of the lever 100 acting on the throttle valve. If this state occurred, for example, while the engine was running should be accelerated rapidly or should deliver a higher power, the stop elements 114 and 116 of the levers are released 100 and 106 against the resistance of the spring 118 for a short time

/ 8 409844/0269

- 8 - 43 919

from each other and then go back to mutual investment, as soon as the time delay or damping device 86 adjusts the connecting rod 82 and the lever 80 by one sufficient amount.

This time delay device 86 is preferably used to overcome a condition known as fuel stagnation can be designated. Fuel is more dense than air and therefore more inertia. Would Thus, the mixing plate 64 is opened quickly, the air flow would increase in volume to the newly specified required air flow rate adapt much more quickly than the fuel. If this were to happen, the fuel-air mixture could be related on the fuel, very well becoming too lean and causing the engine to malfunction. With such a Time delay device 86 is therefore a maximum for the opening movement of the adjustable mixing plate 64 Speed reached to ensure the fuel flow has enough time to respond appropriately to the specified changed fuel flow requirement.

It is evident that when the throttle valve 50 is pivoted clockwise towards its closed position, the valve flap 50 is in the closed position Lever 80 inevitably follows this movement, since the shaft or the connecting rod 84 opposite the piston 90 and is displaceable independently of this opposing resistance. This in turn calls for inevitable adjustment the adjustable mixing plate 64 emerges. From the above it can be seen that with rapid opening of the throttle valve the opening or expansion of the mixing duct lags behind the opening of the throttle valve, so that an accelerator pump can be dispensed with.

It is evident that the fuel flow rate from the fuel float chamber 56 via the fuel outlet opening or nozzle 138 to intake duct 40 mainly from

^ 09844/0269

- 9 - '43 919

pressure difference Δ Ρ utilized for metering or dosing is dependent, which is often referred to as metering vacuum and is determined by the difference PypP ,, ", in the P-, the The pressure prevailing in the fuel float chamber 56 above the fuel 60 and P the often as a mixing channel vacuum or Mixing channel negative pressure is the effective pressure that is in the intake channel 40 at or slightly behind the flow direction Neck or the narrowest part of the mixing channel prevails. This mixing channel neck is labeled with the variable dimension D. For the purpose of explanation it is assumed that P-. to the atmospheric or outside air pressure P is completely the same, although this relationship is not in some applications may apply.

Unlike a carburetor with unchangeable dimensions of the mixing channel neck, which generally results in a volumetric Change in air flow through the mixing duct is a correlated change in the size of the Mixing channel vacuum or negative pressure is generated, has a Carburetors with an adjustable mixing channel do not have such features.

For example, in the case of carburetors with a non-adjustable mixing channel, the vacuum generated in this at the mixing channel neck or negative pressure actually depends on the speed with which the air flows through this mixing channel neck. In reality, however, since the mixing channel neck has an invariably fixed dimension and therefore a fixed one Has flow cross-section, this air flow rate is usually related to the volume, because the specification of the air flow rate is the same either as flow volume or as flow rate, since speed and Volumes are directly related to each other.

In the case of a carburetor with an adjustable mixing channel, however, the cross-sectional area of the mixing channel neck corresponds to

409844/0269

- 10 - 43 919

2411374

changeable dimension D changeable. The air flow rate on the adjustable mixing channel neck therefore has none in all positions of the adjustable mixing plate 64 direct relationship to air flow volume.

Accordingly, it can be seen that in a carburetor with a non-adjustable mixing channel, the vacuum generated in this (negative pressure) is proportional to the square of the volume of air flowing through the intake duct, and that in a carburetor with adjustable Mixing channel such a relationship does not exist, since the size of the adjustable or changeable mixing channel neck can be expanded to various values.

In the carburetor 14, the engine is idling for the purpose of the explanation can be regarded as represented by the positions corresponding to the above-described components Fig. 2, the adjustable mixing plate-64 in relatively a small distance from the non-adjustable mixing channel section 137 »to create a metering vacuum or metering pressure P to be generated, which is sufficient via channels 130 and a metered flow of fuel into the intake channel 40 conduct, although in this operating state the air flow rate is relatively very small in terms of volume. By In this way, the adjustable mixing plate 64 is adjusted to a small distance, it is effected that the volume small air flow rate when the engine is idling accelerates sufficiently at the neck of the mixing channel so that the necessary mixing channel vacuum (mixing channel negative pressure) is generated, will.

Pig. 3 shows a graphic representation of characteristic curves of a carburetor with a non-adjustable one and a carburetor with an adjustable one Mixing channel. For each of these carburettors, the air flow rate in terms of volume is the amount of air generated in the mixing duct Vacuum (negative pressure) applied. Curve A represents the curve that most carburetors do with no

409844/0269 ^{/ 11}

- 11 - ■ 43 919

adjustable mixing channel is generated, curve B is characteristic of a carburetor with adjustable mixing channel Curve.

In the diagram of FIG. 3 it can be seen that the curves A and B, which of course both have to start at the zero point, intersect at a point 150 '. Assuming, furthermore, that a dashed vertical line 152 represents a normal air flow for a particular engine in curb idle operation, this line 152 intersects the curves B and A at a point 154 and 156, respectively, the point 154 for the The vacuum generated in the mixing channel (negative pressure) shows a significantly higher value than point 156. It can also be seen from this that curve B for the mixed channel vacuum (mixed channel negative pressure) ^{for all air flow values between line 152 and point I5O 1} indicates greater Yi / erte than the corresponding section of curve A. It follows that, since such high vacuum or negative pressure values are not necessary during this operating state of the engine, their effect by changing, actually by reducing the effective cross-sectional area of the metering opening with the aid of the interacting valve members 142 and 144 is mitigated, wherein the closure member 146 from the mixing plate 64 is positioned so that it generally reduces the effective flow cross-section at the opening 142 more, the closer the mixing plate 64 approaches the non-adjustable mixing channel section.

Of course, this means that the effect of the actual vacuum or negative pressure generated at the mixing channel neck, the metered fuel flow rate as a factor in the metered fuel flow rate delivered at the nozzle or at the outlet opening 138 received, is reduced to this extent. In addition, when the mixing plate 64 is open, the actual volumetric Air flow rate at the mixing channel neck actually increase by a factor that is significantly greater than that

4098U / 0269

- 12 - 43 919

241 1374

resulting mixed channel vacuum (mixed channel negative pressure) would. To compensate for such a different relationship, the metering element 144 is therefore further to the right adjusted in order to obtain a larger effective flow cross section for the Flud between the opening 142 and the surface of the metering element 144, whereby the there flowing through metered fuel flow rate is increased accordingly, although in the size of actually generated mixing channel vacuum (mixing channel negative pressure) may not be recorded a large increase.

The above description relates to the general mode of operation of the carburetor 14 without taking into account the in their entirety with 160 designated control or correction device, and so as if the line or the channel 162 would not exist.

The sailing device 160 (FIG. 2) can have a housing 164, in which various control devices, for example solenoid-operated valve assemblies 166, 168 and 170 together with an adjusting device 172, which can be adjusted manually in its position, and an external pressure knife 174 are.

The solenoid-operated valve assembly 166 can be designed with two working positions and has a housing 176, the one magnet with electrical connectors 173 and 180 contains. The housing 176 can have a threaded connection 182 may be connected to the housing 164 in such a way that the shaft and closure part 184 are in the closed position a line 186 in order to interrupt the connection between this and a chamber 188 in which the Shaft and closure part 184 is arranged substantially.

The solenoid-operated valve arrangement 168 can be designed as a proportionally acting valve when adjusting the

409844/0269

- 13 - 43 919

associated closure member is essentially proportional to the strength of the signal supplied to its magnetic part, and has a housing 190 in which the magnet with electrical connectors 192 and 194 is received. The case can via a threaded connection 196 in the manner with the Housing 164 be screwed, that a closure member 198 in the closed position on a line 200, thereby establishing the connection between this and a chamber to interrupt, in which the closure member 198 is essentially is arranged.

The solenoid-operated valve arrangement 170 can be designed with two working positions and has a housing 204, which includes a magnet with electrical connectors 206 and 208. The housing 204 can have a threaded connection 210 be screwed to the housing 164 in such a way that the shaft and closure part 212 in the closed position on one Line 214 are applied in order to interrupt the connection between this and a chamber 216 in which the Shaft and closure part 212 is arranged substantially.

As can be seen from the drawing, the various chambers 216, 202 and 188 can communicate with one another via lines 218 and 220, which ultimately lead to a conduit that is connected to the ambient or at an opening 224 Outside air or with a corresponding source connected to it.

The voltage source supplying the magnets is known per se and is therefore not shown and can be the vehicle battery be.

The manually adjustable adjustment device has an in ' Axial direction screw-adjustable main part 226, which carries a closure part 228, to change the effective Flow cross-section between a chamber part 232 and a

/ 14 409844/0269

- 14 - 43 919

2411374

Line 234 is able to interact with a seat 230. As As shown in the drawing, the chamber 232 is in communication with the outside air via a line section 236, while the Line 234 is connected to lines 162, 186, 200 and 214 and to a line 238 which is essentially leads to altitude meter 174.

The external pressure and altitude meter 174 can be one in the axial direction screw-type adjustable evacuated pressure can arrangement 240, which is housed in a chamber 242 and is screwed to the housing 164 at one end 244 and is operatively connected at another end 246 to a lever 248, one end of which is pivotable into a pivot bearing 250 is mounted and the other end 252 is pivotable and operable with a locking member 254 is connected, which is displaceable in a guide channel 256.

The closure member 254 may have a main portion 258, which is essentially diamond-shaped in cross-section and therefore does not hinder the flow passing by it. A closure part 260 can cooperate with a corresponding seat 262 to prevent the flow at this point and through line 238 to regulate. Chamber 242 is over a ventilation duct 264 expediently supplied with outside air.

It can be seen that line 162 is connected to line 234 at one end, but to a region at the other end which is located essentially in front of the precisely dimensioned opening or throttle point 142.

Let us now consider the overall operation of that illustrated in FIG Carburetor described in training according to the invention. It ssi assume that valves 260, 228, 184, 198 and 212 are all are closed first. Then you can see that in operation

/ 15 409844/0269

- 15 - 43 919

of the motor the size of the variable pressure P in the Chamber 266 is substantially equal to the size of the variable pressure P, which is generated in the mixing channel neck, and the Curve B in Fig. 3 would correspond. Furthermore, this particular assumed operating condition would result in a first air-fuel ratio lead, as is shown essentially by the curve 270 in FIG. 4, in which a vertical Line 272 corresponds to line 152 in FIG. 3. The graph in Fig. 4 is obtained by plotting the air-fuel ratio (K / L), in which the fuel is in English. Pounds (1 Ib = about 0.454 kg) and the air in English. Cubic Feet (1 cu.ft. = approx. 28.32 dnr) are given above the air flow in English. Cubic feet.

It is now assumed that the manually adjustable valve 172 is opened somewhat, whereby the relatively high pressure P ₀ causes air flow from the opening 224 via the line 236, the chamber 232 and the lines 234 and 162 into the chamber 266, which in turn the magnitude of the pressure P can be effectively increased and the effect of the mixing channel vacuum (mixing channel negative pressure) generated can be effectively reduced. This naturally causes a reduction in the metering vacuum, which is now determined by the difference Pt ₃ -P, and therefore a reduction in the metered fuel flow rate at the opening or throttle point 142, although the air flow rate has remained the same. In this second assumed operating state, the resulting fuel-air ratio would be reduced or, in relation to the fuel, made leaner and could be represented by curve or line 274 in FIG. 4. Furthermore, for the sake of general explanation, the size of P could essentially be represented by the dashed curve 276 in FIG , the sampled quantity of P is actually the generated mixing channel pressure.

4098U / 0269

- 16 - 43 919

2411374

Taking the above into account, one can therefore see that the more air is applied to the chamber 266, the more the fuel-air ratio of the resulting gas mixture gets leaner. One direct benefit to be drawn from such a training is that a carburetor manufacturer which, in terms of costs, has the very advantageous possibility of producing carburetors which, as one could call it, are a mixture dispense with a standard air-fuel ratio as shown by curve or line 270, and then the motor manufacturer or a comparable customer to manually set the size of the ventilation with the setting device 172 to make the air-fuel ratio of the mixture according to the requirements of a downsize any or all motors. Of course, this setting could also be made by the carburetor manufacturer are made in accordance with the customer's instructions. What matters here, however, is that the carburetor is basically could be a standard device.

If the air-fuel ratio is now as in the diagram of the 4, as the ratio of the fuel flow in units of weight to the air flow expressed in units of volume, it is clear that at reduced atmospheric pressure due to greater altitude, the density of the air flowing through the intake duct 40 is reduced, and that this is a Reduction of the metered fuel flow rate required even if the generated mixing channel vacuum (mixing channel negative pressure) can usually indicate another measure. That means, for example in comparison with an air-fuel ratio at sea level according to curve 274, that the curve for that at any higher altitude required or appropriate fuel-air ratio can be given by the dashed curve 278.

This is achieved with a pressure cell 240, which is dependent on the decrease in size of the pressure P in the axis Increased direction and therefore the closure member 254 after

409844/0269 / r,

- 17 - 43 919

2411074

adjusted down and the effective flow cross-section at the seat or at the opening 262 increased to a certain extent. The chamber 266 is pressurized with atmospheric air via the line 264, the chamber 242, past the valve 254 and through the seat 262 and the lines 238, 234 and 162, whereby the pressure P is compared with the actual size of the mixing duct pressure P generated is enlarged. Here, too, the above-described processes result in a reduction in the metered fuel flow rate passing through the opening 142 compared to the fuel flow rate which would be metered if the actual size of P _{v were} plotted on the low-pressure side of the opening or throttle point 142. Such a regulated or corrected value of the pressure P could, for example, be regarded as a "false" mixed channel vacuum and, depending on the degree of opening or ventilation, for example as a curve such as curve 276 or 280, or even as any of the other proportional curves of FIG Fig. 3 are shown, which are lower than the curve B.

In the example shown, the valve assembly 168 is similar to the external pressure and altitude gauge 174 in that each of these two devices acts proportionally and the degree of ventilation or secondary air supply according to a predetermined Plan or predetermined input parameters can be changed continuously. As also shown in the preferred Form the valve assemblies 166 and 170 executed with two working positions, namely either with the closed or with the ventilation open. The effect of any or all of these valve or control devices Ventilation made has been explained in detail in connection with the adjustment device 172 and the external pressure and altitude meter 174 described.

Ks now follows the description of the operation of the invention trained carburetor taking into account a normal operating environment. For easier understanding, in

4098A4 / 0269

/ 18th

- 18 - 43 919

Fig. 1 shows parts of the valve assemblies 166, 168 and 170. The speed sensor and meter 34 generates a signal K, which is transmitted via a corresponding signal transmission device 282 can be fed to a corresponding, connected transducer 284. As soon as the appropriate Value or magnitude of the signal N is generated, the transducer occurs 284 in action and switches on the valve arrangement 166 via a conductor 286 in order to adjust of the closure member 184 (FIG. 2) to the left to open the ventilation channel 186.

In a similar way, the oxygen sensor 32 can continuously generate a signal 0, which is transmitted via a corresponding signal transmission device 288 can be fed to a corresponding, connected transducer 290. If ever the value or the magnitude of the signal 0, which is expressed as the relative amount of carbon monoxide can be considered exceeds a predetermined amount, the transducer 290 enters Activity and switches on the valve arrangement 168 via a conductor 292 in order to adjust the closure member to open the ventilation duct 200 with different open positions by a certain amount to the left and essentially in accordance with the size of the signal 0. adjustment of the closure member to the left means leaning, to the right means enrichment of the mixture.

In the example shown, the valve arrangement 170 is connected via conductors 294 and 300 to one of two transducers 298 and 298, respectively. 296 can be activated or switched on. The transducer 296 responds to a signal M which it receives via a signal transmission device 302 and displays the pressure or vacuum (negative pressure) in the engine intake manifold. With everyone When the engine decelerates, the throttle valve 50 is closed and the vacuum (negative pressure) in the intake manifold then exceeds the size of the vacuum created there when the engine is idling. Therefore, when such a signal M indicates that the engine is decelerating learns, the transducer 296 enters into

409844/0269 / ₁₉

- 19 - 43 919

Activity, mn adjustment of the closure member 212 of the valve arrangement 170 to the left and thereby the ventilation duct 214 to open. In addition, the transducer 298 speaks to "closing and / or opening" for example of a vehicle ignition switch 304. Part of the ignition circuitry connected to this is labeled 306, a connected electrical voltage source is designated by 308 ". Essentially, the mode of operation consists in the fact that the transducer 298 is also set in action when the ignition switch 304 is open by adjusting the closure member 212 of the valve arrangement I70 to the left to open the ventilation duct 214.

Due to various general or legal regulations regarding pollutant emissions in vehicle engine exhaust the automotive industry has generally determined that in order to comply with the pollutant emission regulations, especially with regard to the elimination of nitrogen oxides from engine exhaust gases, in all likelihood after catalytic converter in the engine exhaust gas exhaust system must be installed. Although converters of this type can be designed in different ways, they are generally included in the calculation two-stage converters, the first stage as a reduction chamber or stage, the second as an oxidation chamber or stage is executed. These are shown schematically in FIG. 1 and denoted by 28 and 30, respectively.

In the first stage, the reduction chamber or stage 28, there is a reaction between the nitrogen oxides and a part of carbon monoxide. This releases free molecular nitrogen and carbon dioxide, with additional amounts of carbon monoxide and methane, for example, being used. The free nitrogen and the carbon dioxide are released into the atmosphere without further reaction, while the methane and other such Exhaust components and the remaining carbon monoxide are then oxidized in the second stage, for example by reaction

/ 20 409844/0269

- 20 - 43 919

2411374

and give carbon dioxide and free water.

In order to achieve this chemical conversion, it is necessary to provide the engine with an over-rich fuel-air mixture with increased To supply fuel portion, so that the exhaust gases in the in the direction of flow in front of the reactor 28 and The area sensed by the sensor 32 is about 1.5 / ° carbon monoxide (GO) included. As a result, there is then a sufficient amount of CO for the reaction in the reduction stage 28 and for it to be carried out the oxidation in stage 30 a sufficient excess of CO to disposal. Of course, the carburetor can be adjusted from the start so that this 1.5 ^ ige CO share results. One at this air-fuel ratio The usual curve is designated by 310 in FIG. 5.

However, at relatively high driving speeds with normal or greater than normal driving resistance The problem is that at speeds over, for example, about 88.5 km / h, the converter is often overheated due to the amount of such over-rich mixture passed through it in the unit of time. At speeds above the assumed value of about 88.5 km / h, the signal N therefore becomes so strong that it becomes the measured variable uniform switches on, which in turn causes the ventilation channel 186 to open with the closure member 184 of the valve arrangement 166, with the result that, as already explained above, the pressure P rises and the metered fuel flow rate increases decreases. This results in a leaner fuel-air mixture in relation to the fuel content. the The curve of the corresponding air-fuel ratio is denoted by 312 in FIG. 5. The degree of ventilation or the strength of the secondary air would be such that that of curve 312 corresponding fuel-air mixture is sufficiently lean to at speeds above the assumed approximately 38.5 km / h To prevent overheating of the exhaust gas converter.

409844/0269

- 21 - 43 919

The illustrated valve assembly 170 is normally closed, with "normally" indicating those engine operating conditions are meant that are not characterized by switching off or delaying or slowing down the motor. In Operating states with engine delay in which the size of the signal M for the pressure in the intake manifold, based on If the pressure is sufficiently small or, in relation to vacuum, sufficiently large, the transducer 296 causes the closure member 212 of the valve assembly 170 opens the ventilation channel 214, whereby, as described above, the size of the pressure P increases and the metered fuel flow rate is reduced so far that the resulting fuel-air mixture, as it is, for example, as a fuel-air The ratio represented by curve 314 in FIG. 4 is too lean to be combustible. If you look at that too value of the pressure P valid at this point in time as a value indicating an "incorrect mixing channel vacuum" graphically represent this with a point 316 in FIG. In such operating states of the engine deceleration, the metered fuel flow rate is drastically reduced and leads to a corresponding reduction in exhaust gas pollutant emissions.

Since the proportion of fuel in the fuel-air mixture can be reduced so much that the mixture is then extremely lean is no longer combustible, the valve arrangement can also be used to control the fuel-air mixture that is in the Moment of switching off the engine flows to lean, in order to prevent the occurrence of the state that is often referred to as "continued running of the engine due to glow ignition". When the ignition switch 304 is opened, namely the transducer 298 is switched on and this also causes the closure member 212 of the valve arrangement 170 adjusted and the ventilation channel 214 opens, with the result that in this case, too, point 316 in Fig. and point 318 in Fig. 4 can be obtained. Because at that time

409844/0269

- 22 - 43 919

the air-fuel ratio is designed so that the If the mixture is not combustible, the engine is prevented from continuing to run due to glow ignition after the ignition has been switched off.

The various parameters and devices that these sample and generate signals in response to are only given as an example. It should be understood that the invention includes a carburetor fuel delivery system which includes a sail device which controls the air-fuel ratio of such a carburetor dispensed fuel-air mixture is able to change depending on operating parameters, which any, Show the state created by the engine itself.

In addition, as shown in general form in FIG Mixing channel applicable.

In the example shown in FIG. 6, a carburetor 320 has a body or housing 322 through which an intake passage 324 passes, the air inlet side 326 of which with a starter flap 328 whose position can be changed can be controlled, and in its outlet side or outlet end 33O a throttle valve whose position can be changed 332 is arranged. The latter is used to regulate the flow into an inlet 334 of an intake manifold chamber 336 of a Engine intake manifold 338 directional flow of combustible Mix. The intake manifold 338 can actually be like the In Fig. 1 and 2 shown intake manifold be formed.

The carburetor can be connected to a fuel idle system 340 and a main fuel system 342 which are well known. The fuel idling system shown only in part 340 has a fuel supply line that leads to fuel 346 in a connected fuel tank or fuel supply device 348 leads and

409844/0269

- 23 - A3 91?

communicates with intake duct 324 via ducts 350 and 352 stands. When idling, fuel is fed through channel 350 into the intake channel downstream of the throttle valve 332 in the direction of flow when the throttle valve is in the closed idle position, as shown in the drawing. at Pivoting throttle 332 clockwise toward its open position during shutdown and idle The channel 352 makes increasing amounts of fuel available to various operating phases of the engine.

The main fuel metering system 342 drawn in a somewhat simplified form can have a fuel outlet nozzle 354 which is arranged essentially in the mixing channel neck 356 of a non-adjustable mixing channel 358 and the opening 360 of which leads to a fuel supply line 362, which via an exactly dimensioned opening or Throttle point 364 is connected to the fuel 346. As soon as the air flow rate in the mixing duct neck reaches a sufficient size, the resulting mixing _{duct pressure P is sufficiently low so that the pressure difference P-b} -P _v causes fuel to flow through duct 362 and opening 360 into intake duct 324.

As shown in general form, the carburetor 320 is detailed with that in connection with FIGS. 1-5 described control device 160 connected in such a way, that the secondary air line 162 is connected to the fuel supply line 362. The way it works is of course as described in connection with FIGS. 1 and 2, with the result that in this case too a carburetor system with regulation is obtained.

In addition, the carburetor shown in FIG. 6 and the control device shown in detail in FIG. 2 can be used if necessary 160 in such a way that one in the housing 322 is connected to the fuel idle line 344

409844/0269 / 24

- 24 - 43 919

241 '074

standing channel 366 and through. Insertion of a locking member into line 234 between line 214 and & n lines 200 and 162 the ventilation duct 214 (Fig. 2) of the lines 200 and 162 separates. With such a modified one Formation would be a second ventilation or secondary air line working essentially like the line 162 162a connected so that it is then connected to lines 214 and 366 in connection. Thus, the pressure that results from the auxiliary air supply through line 214 during shutdown or deceleration of the engine, in the direction of flow before the channels 350 and 352 and after the associated, designated in their entirety with 368 Fuel idle metering device lying area applied.

From Fig. 7 it can be seen that the invention in its simplest form consists in that when P is a pressure generated by the velocity at which air flows into an engine, P is atmospheric pressure and P is the pressure with to which the fuel is applied, in which case P ^ and P are assumed to be the same size, with a device, for example with the device 160, which responds to operating state parameters of the engine and / or the vehicle, the actual, existing and used for metering pressure difference I * -u-? _{v can be} changed in order to differently throttle the outside air flow for more precise supply of the motor with scanned or measured parameters of this type, with a device 370, which is equivalent to the valve arrangements of the control device 160, in order to generate a control or correction pressure P and thereby to produce an actual and changeable pressure difference Pt ₃ - ^ ₀ which can be used for metering and which, when applied to the associated, precisely dimensioned metering opening or metering nozzle 372, ensures exactly the appropriate metered fuel flow rate to the outlet area designated in its entirety by 374, in which the relatively low Pressure P prevails.

409844/0269 / ² -

- 25 - 4? 919

2 A11874

It should be noted that various modifications and configurations of the invention are possible. For example can be used to generate the feedback signals to which the Ability to address illustrated control device or any other device, various engine operating state variables as well as various parameters are used. For example, in addition to those shown in FIG Valve assemblies shown used auxiliary air valve assemblies that respond to other operating parameters. It is also possible to use other, special valve arrangements To use training forms, for example, pressure-sensitive devices in execution with a membrane or the like. Others that can be used to implement the idea of the invention Means are accessible to those of ordinary skill in the art.

The invention is not restricted to the above exemplary embodiments, but rather within the scope of this basic concept can be modified in many ways.

/Expectations

409844/0269

Claims (24)

.EXPECTATIONS Fuel metering device for an internal combustion engine, with an intake duct with a mixing duct arranged therein, in which, depending on the air flowing through it a low first pressure is generated, which is used in connection with a relatively high second pressure, by the amount of fuel flowing into the intake duct metering, characterized in that responding variables indicating engine operating states with one additional device (160,162; 160,162,162a) temporarily with a correction pressure (P ") the effective size of the first Pressure (P ") as a function of the blotor operating state variables mentioned can be changed in order to thereby determine the effect of the first pressure (P ") on the metered fuel flow rate to change accordingly and thereby the metered fuel flow rate at any time to the engine operating state variables to match. 2. Fuel metering device according to claim 1, characterized characterized in that the additional device (160,162) comprises a device (170) which is responsive to delay of the motor (10) responds. 3. Fuel metering device according to claim 1, characterized characterized in that the additional device (160,162) comprises a device (166) which on the Engine speed responds. 409844/0269 43 919 4. Fuel metering device according to claim 1, characterized in that the additional device (160,162) has a device (170) which responds to switching off the motor (10). 5. Fuel metering device according to claim 1, characterized in that the additional device (160,162) comprises a device (170) which is responsive to the pressure in the engine intake manifold (12). 6. Fuel metering device according to claim 1, characterized characterized in that the additional device (160,162) comprises a device (168) which is based on the Presence of oxygen in the engine exhaust responds. 7. Fuel metering device according to claim 1, characterized characterized in that the additional device (160,162) comprises a device (170,166) which on Delay and speed of the motor responds. 8. Fuel metering device according to claim 1, characterized gekennz eichnet that the additional device (160,162) comprises a device (170,168,298) which on Delay, speed and shutdown of the motor (10) responds. 9. Fuel metering device according to claim 1, characterized in that the additional device (160,162) has a device (170,166) which controls the deceleration, speed and switching off of the motor (10) as well as is responsive to the presence of oxygen in the engine exhaust. 10. Fuel metering device according to claim 1, characterized in that the additional device (160,162) comprises a device (240) responsive to atmospheric pressure. 409844/0269 43 9'9 11 .. Fuel metering device according to claim 1, characterized characterized in that with a manually adjustable device (172) the effective size of the first pressure (P) can be changed by hand. 12. Fuel metering device according to claim 1, characterized in that the additional device (160,162, 160,162,162a) has a secondary air device (224,222,234, 186,200,214,162,266) which essentially connects a source of relatively high air pressure connected to the outside air with an area (266) , in which the first pressure (P _v ) prevails. 13. Fuel metering device according to claim 1, characterized characterized in that the additional device (160,162; 160,162,162a) a secondary air device (224,222,234, 186,200,214,162,266), which essentially has a relatively high source connected to the outside air Air pressure connects to the area (266) in which the first pressure (P) prevails, and that with valve arrangements (166,184; 168,198; 170,212), which respond to the engine operating state variables mentioned, the secondary air device (224,222,234,186,200,214,162,266) vary substantially according to these engine operating state variables open and close. 14. Fuel metering device according to claim 1, characterized characterized in that the mixing channel is adjustable with a device (64). 15. Carburetor, in particular according to claim 1, for an internal combustion engine, characterized in that a housing (38; 322) from an intake duct (40; 324) is penetrated, which at one end has an air inlet (42; 366) and at the other end an outlet (44; 330) that with a first device (128,137,64; 354,356) a fuel metering pressure by generating a first, proportionately 409844/0269 / 4 43 91 s low metering pressure (? ") of variable size depending on the air flow rate going through the Änsaugkanal (40; 324) can be produced that a fuel metering device (142,144; 364) with a fuel source (54; 348) and the intake duct (40; 324) is in communication and is arranged so that its one end is substantially exposed to the fuel metering pressure in order to supply a metered fuel flow rate to the intake duct (40; 324) depending on the size thereof, and that a secondary air device (160) is essentially connected to a source of relatively high air pressure connected to the outside air and to one end of the fuel metering device (142, 144; 364) and supplies the air under high pressure as air from the side by the size of the fuel metering pressure effective with a correction pressure (3? _c ) to increase without changing the size of the first, relatively low metering pressure, and thereby the train Measured fuel flow rate to the intake duct (40; 324) to decrease. 16. Carburetor according to claim 15, characterized in that g e k e η η, that the first device (128,137,64) has a mixing element which can be adjusted into various open positions (64). 17. Carburetor according to claim 15, characterized in that the first device (128,137,64) is a Mixing element adjustable in different open positions (64) which is operationally connected to a throttle valve (50) via devices (80,82,106,100,118), which is connected downstream of the mixing element (64) in the direction of flow in the suction channel (40). 18. Carburetor according to claim 15, characterized in that the first device (354,356) is a has non-adjustable mixing element (356 and / or 354). 409844/0269 ^{/ 5} -Ψ- 43 9iy ¹⁰ 2 411 β 7 Λ 19. Carburetor after. Claim. 1 5, characterized in that the secondary air device (160) in different Open positions adjustable secondary air ducts (264,260,262,238,234,162), the effective opening widths of which essentially depend on the outside air pressure are controlled by a device (240). 20. Carburetor according to claim 15, characterized in that g e k e η η, that the secondary air device (160) adjustable lifting air ducts (224, 168,200,222,23 4,162), the effective opening widths of which essentially depend on that in the engine exhaust gases existing amount of oxygen are regulated. 21. Carburetor according to claim 15, characterized in that the secondary air device (160) in different Open positions adjustable living air ducts (224, 222,218,170,212,214,234,162) whose opening widths depend on the engine operating states "engine deceleration" are regulated. 22. Carburetor according to claim 15, characterized in that g e k e η η, that the secondary air device (160) adjustable secondary air ducts (224, 222,166,184,186,234,162), the opening widths of which are regulated as a function of the engine speed. 23. Fuel metering system, in particular according to claim 1, for one Engine that uses fuel from a fuel source an exactly dimensioned throttle point in metered quantities an intake duct connected to the engine is supplied, wherein the fuel source is subjected to a first, relatively high pressure and a second, relatively low pressure of variable magnitude is generated according to the air flowing into the engine, and where the size difference between the two presses for / 6 403844/0269 - / - 43 9'9 ^ 2411Π7Λ Generating a pressure difference that is used to measure the fuel is used essentially between 'the fuel source and the throttle point, characterized in that essentially in the direction of flow a chamber (266; 362) is formed behind the precisely dimensioned throttle point (142; 364) which at least temporarily IS secondary air in variable strength can be supplied to thereby generating a third pressure (P_) in the chamber (266; 362), the magnitude of which is greater than the second pressure (P "), and that the strength of the vines air supplied to the chamber (266; 362) has a level responsive to engine operating conditions Device (160) is adjustable. 24. Fuel metering system, characterized in that that the precisely dimensioned throttle point (142; 364) is part of a fuel idling system (340) of a carburetor (320) is. 409844/0269 Blank page