DE1281748B - Carburettors for internal combustion engines - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

F 02 m

German class: 46 c2 - 15/01

Number: 1281748

File number: P 12 81 748.0-13 (S 88713)

Filing date: December 13, 1963

Opening day: October 31, 1968

The invention relates to a carburetor for internal combustion engines with a fuel supply via Valves that control a standard cross-section, influencing, responding to the negative pressure in the intake duct Pre-throttle valve and one arranged downstream thereof, which can be actuated arbitrarily Main throttle, a constant level fuel chamber, one between both throttle valves Connection opening opening into the intake duct from the connection opening located downstream of the standard cross-section Area of the fuel channel system leading to the fuel nozzle, a connection between the constant level fuel chamber and the atmosphere and that between both throttle valves lying area of the intake duct.

There are known carburetors for internal combustion engines in which the intake duct is upstream of the The main throttle valve operated by the driver has a vacuum-controlled pre-throttle valve, which controls a fuel metering member depending on its opening angle, the upper part of the float tank on the one hand with the outside air or the air inlet of the carburetor and on the other hand communicates with the area delimited in the intake duct by the two throttle valves. Furthermore, carburetors are known in which this connection of the float tank with the between the area lying between the two throttle valves, in which, in general, a practically constant There is negative pressure, can be interrupted or opened by the driver at will. If the float tank is connected to this area, there is a smaller negative pressure in it than in this area between the two throttle valves, while otherwise at atmospheric pressure is applied. This enables the driver to adjust the air-fuel mixture when starting the engine and to enrich the operation of the cold engine by making the connection between it Area and the float tank is interrupted, whereby the prevailing in the float tank Pressure and thus the pressure difference determining the amount of fuel is increased.

The present invention is based on the object of such a carburetor so that in each In case the content of the mixture is automatically adapted to certain engine operating conditions which are independent of its temperature.

This object is achieved according to the invention in that one of the downstream of the arbitrarily actuatable Main throttle valve in the intake port, pressure-controlled valve making the connection Carburettors for internal combustion engines

Applicant:

Societe Industrielle de Brevets et d'Etudes

S. I. B. E., Neuilly-sur-Seine (France)

Representative:

Dr. F. Zumstein, Dr. E. Assmann

and Dr. R. Koenigsberger, patent attorneys,

8000 Munich 2, Bräuhausstr. 4th

Named as inventor:

Andre Louis Mennesson, Neuilly-sur-Seine

(France)

Claimed priority:

France of December 27, 1962 (919 893)

between the area of the intake duct located between the two throttle valves and the atmospheric area Controls connection of the fuel chamber with constant level.

In a favorable embodiment, this carburetor is in internal combustion engines with at least three Cylinders designed so that the pressure in the intake duct downstream of the arbitrarily actuatable Main throttle valve controlled the connection between the float chamber when the load increases and the area of the intake duct located between the two throttle valves Has valve cone.

Such a carburetor is advantageous in internal combustion engines with one or two cylinders designed so that it is controlled by the negative pressure downstream of the arbitrarily operable main throttle valve With increasing load, valve one the connection between the float chamber and the between Has two throttle valves lying area of the intake port releasing valve cone.

Exemplary embodiments of the present invention are described below with reference to FIG Drawing explained in more detail in the

809 629/1235

Fig. 1 shows a first embodiment of an invention 4 determined in the throttle point 15 passage

represents the carburetor according to the invention in section; cross section for the fuel practically proportional

FIG. 2 shows similarly to FIG. 1 a modification which is, and that the air and the fuel, thus

ses carburetor according to the invention; are delivered under the same pressure difference

Fig. 3 shows the operating chemistry of a mixture according to the invention with a practically constant composition

proper carburetor again; form. With numerous, by such a

FIG. 4 shows, similar to FIG. 1, a second exhaust gas-fed engine type, however, the changes

form. optimal composition of the mixture in

In the intake duct 1 of the carburettor shown, the main factor of the amount of air taken up by the engine depends on the load on the engine and / or on a shaft 6,
throttle valve 2 and upstream of this in the air inlet Fuel metering member controls. On the other hand, it is connected to the area 10 via a duct to the negative pressure 15 38 prevailing in the intake duct 1, a valve being provided which can shut off the appealing, eccentrically mounted pre-throttle duct 38 and is designed in this way, flap 3 on which a return device , for example that it automatically engages a spring 9, depending on the type of motor, is loaded by the shaft 8 in function. The channel 38 opens into two zones, namely a zone S'-with preferably, as shown, not directly in the relatively smaller and a zone S with a relatively large float tank 11, but rather it has a relatively large surface on the channel. Connected in certain special cases, so that. These-two channels through len, the pre-throttle valve 3, for example, through a common opening. 39 with the float displaceable, transversely into the air inlet cross-section 7 container are in connection. These two channels protruding pistons and a spring-loaded valve also have calibrated throttle points 40 and 41 or the like. . 35, the cross section of which has the value of the compared to the

The fuel is through the channel 5 at an underpressure of the area 10 moderated underpressure

Sucked into the suction channel 1, at the prak- determine, which is located in the float tank 11 on-r

table builds the same pressure as between the two when channel 38 is open. .

Throttle valves prevail. Through the choke, in general, requires proper work

Flap 3 is in the area 10 between the two 30 of an engine a mixture enrichment with strong

maintaining negative pressure on the throttle, loads. For this "this valve is designed so"

which is practically constant or at least according to the fact that it cuts off the channel 38 at high engine load

a certain function that blocks the intake duct 1, but it does so at low and medium loads

incoming air volume is variable. The burning (Fig. 1) releases, the value of the load

material is from the float tank 11, which is a 35 through the suction channel 1 downstream of the main

Float valve 12, 13 and a feed line 14 throttle valve 2 prevailing negative pressure or else

has to be determined via a calibrated throttle point 15 in a by the degree of opening of this flap

Kammerlö sucked, which can with the float tank. For this purpose, as can be seen from FIG. 1, in

through a channel located below the level iV 17 channel 38 a valve cone 42 is arranged, which with

communicates. The channel 5 is connected to the chamber 40 of a membrane 43, which is in a

16 delimits a chamber 45 with respect to the channel 17 on the other side of the housing 44. This cam-

Throttle point 15 connected. The metering member is mer 45 is through the channel 46 with the downstream

by a conical needle 4 with a slide rod 18 of the main throttle valve 2 area of the

formed in a guide 19, which is connected to the top in the air intake duct 1, wherein a spring 47

Let section 7 upstream of the throttle valve 3 45 opposite to that via the channel 46 on the membrane

and ends below level N. 43 transferred negative pressure acts. As from Fig. 1

According to the Lö- shown in FIGS. 1 and 2, the channel 38 can pass through an opening 48 Solution can open the channel 5 with the area 10 through into the area 10 of the intake duct 1, the an opening 20 to be connected, so that in the at any degree of opening of the pre-throttle throttle point 15 by the needle 4 metered 50 combustion flap 3 is downstream of this, so that only the fabric by suction in the area 10 of the load in the suction channel formed in the float tank 11 1 reached. According to another embodiment, pressure is influenced.

The channel 5 can be formed into a passage. With the composition of the mixture changed not only in the solution shown in FIG of the intake channel prevailing pressure amount in the intake channel 1 is independent of the acted upon and load with the suction side of a pump is also via another given 23 in connection. This pump promotes the limit value increases. In this case, the fuel dosed by the needle 4 does not flow through an opening 48 (Fig. 1), the at least one injection nozzle 24 downstream of the main throttle valve 3, main throttle valve 2, but through an opening 48 a (Fig. 2), which is so atWhen the float tank 11 is permanently disordered that it is not connected to either the air inlet section 7 or the throttle valve from the upstream to area 10 during the gradual opening, prevails in the downstream side of this comes to rest, the pressure. It is clear that then the process shown in FIG. 1 and 2 shown throttle valve 3 in the intake channel 1 certain through-carburetor is then explained with reference to the cross-section for the air and the Na- Fig. 3, which represents a curve, the decrease

szissa the speed V of the engine and its ordinate indicates the composition α of the mixture to be supplied to the engine, the composition z. B. is defined by the ratio between fuel and air weight in the mixture.

In engines that have more than two cylinders, for example four, six or eight, the composition of the mixture fed to the engine at full load must generally be richer in fuel than at part load. These requirements can be met with an embodiment according to FIG. 1, in which the composition of the curve ABCD (Fig. 3) changes. In the section AB , the load on the engine has a small or medium value, and the negative pressure transmitted to the chamber 45 is relatively large (in absolute terms). The valve cone 42 is inoperative and releases the channel 38 (FIG. 1), so that there is a moderate negative pressure in the float tank 11, the value of which depends on the cross section of the calibrated throttle points 40 and 41. The amount of fuel determined by the difference between this reduced negative pressure and the full negative pressure at the opening 20 is relatively small, and the mixture delivered through this opening is relatively poor.

In section CD of the curve in FIG. 3, on the other hand, the engine load is high and the negative pressure transmitted to the chamber 45 is relatively low. The valve cone 42 blocks the channel 38 so that the same pressure prevails in the float tank 11 as in the air inlet section 7. The amount of fuel determined by the difference between this pressure and the negative pressure at the opening 20 is then greater than in the previous case, so that the mixture is enriched.

However, if an engine must receive a relatively poor mixture at part load in almost the entire normal range of use, it needs a relatively rich mixture at high load and speed. If, as in FIG. 1, simply the negative pressure prevailing in the intake duct 1 behind the main throttle valve 2 is used to reduce the pressure in the float tank 11, there is a sudden transition from one content to the other according to the dashed curve BC (FIG. 3), which results in an intermittent transition Work can result. In contrast, the arrangement of the opening 48a (FIG. 2) enables a more continuous transition along the dash-dotted line B'-C. During the transition from the area AB ' to the area CD , the opening 48 a comes from the upstream side of the pre-throttle valve 3 to lie. The negative pressure prevailing in the region 10 of the intake duct is then no longer transmitted via the duct 38, but a pressure which increases up to that prevailing in the air inlet section 7. These conditions are then as if the valve cone would gradually come into operation, and the mixture is continuously and steadily enriched between the two operating states between partial load (A-B ') and full load (CD). In this way, the composition of the mixture fed to the engine is precisely matched to the operating conditions in each case.

In conventional engines with only one or two cylinders it has been found that the fuel content the mixture fed to the engine at full load must generally be less than that at part load, this case is more common if the carburetor is the one shown in FIG. 4 has the type shown, in which the previously dosed fuel is conveyed by a pump 23. In this case a Valve cone 42α (Fig. 4) used, the reverse how the poppet 42 of the first embodiment (Figs. 1 and 2) works; H. that the channel 38 at is shut off under low loads and released at high loads (FIG. 4). In the embodiment according to FIG. 4 it is assumed that, as above, the loading from the downstream of the main throttle valve 2 prevailing pressure is determined, so that the system for actuating the valve cone 42a is identical to that of the valve cone 42 of FIGS. 1 and 2, except that the spring 47 denotes the Valve cone 42 α pushes in the opening direction.

As already stated above, the load due to the angular position of the main throttle valve 2

so determined. A HebeF attached to the shaft 6 can press with its other end directly on the membrane and thus on the valve cone 42 α.
As dot-dashed in FIG. 4, the channel 38 can open into the region 10 through an opening 48 which is located downstream of the throttle valve 3 at any desired opening angle, so that only the load influences the pressure developing in the float tank 11. To avoid intermittent work when changing from one type of mixture to another, it is advisable to use the amount of air in the intake duct in order to achieve a constant change in the composition of the mixture. For this purpose, the channel 38 opens, as in FIG. 4, shown fully drawn and in phantom, through an opening 48b which is arranged so that it comes to rest when the throttle valve 3 is gradually opened from the upstream to the downstream side thereof.

The in F i g. 4 carburetor works as follows:

With low and medium engine load (low or medium opening of main throttle valve 2) the valve cone 42 α is activated by the negative pressure transmitted to the chamber 45 (FIG. 4), so that on the float tank 11, the pressure from the air inlet section 7 via the channel 34 is transmitted. The normal mixture is fed to the engine. With heavy loads it will

In contrast, the valve cone 42 α by the spring 47 put out of operation, so that in the float tank 11 with respect to the in the area 10 prevailing negative pressure weakened negative pressure prevails. The mixture supplied to the engine then becomes impoverished.

If channel 38 opens at 48 (FIG. 4), this depletion occurs at a given exposure limit. If, however, the channel 38 opens at 48 b, the depletion is performed gradually, ähnlieh the processes in the field of continuous enrichment B'-C in Fig. 3.

With the present invention, the composition of the mixture supplied to the engine be adapted under all circumstances to the operating condition of the engine concerned. Given a Engine and carburetor type, it is possible to determine the change through very simple experiments, those in the composition of the mixture

made depending on the load must be used, and whether the amount of air may be used to determine this change must become.

Claims (3)

Patent claims: 1. Carburetor for internal combustion engines with a fuel supply via valves that control a standard cross-section, influencing, on the Negative pressure in the intake duct responding pre-throttle valve and a downstream of this, Arbitrary L main throttle, a fuel chamber constant Levels, a connection opening opening into the intake duct between the two throttle valves from the area of the area leading to the fuel nozzle, which is located downstream of the regular cross-section Fuel channel system, a connection between the fuel chamber constant Levels and the atmosphere and that between ad area of the intake duct lying between the two throttle valves, characterized in that that one of the prevailing downstream of the arbitrarily operable main throttle valve in the intake port Pressure controlled valve the connection between the between the two throttle valves lying area of the intake duct and the atmospheric connection of the fuel chambers controls at a constant level. 2: Carburetor for internal combustion engines according to claim 1, characterized in that, in internal combustion engines with at least three cylinders, the valve controlled by the pressure in the intake duct downstream of the arbitrarily operable main throttle valve has a valve cone which, when the load increases, interrupts the connection between the float chamber and the area of the intake duct between the two throttle valves having. 3. Carburetor for internal combustion engines according to claim 1, characterized in that in internal combustion engines with one or two cylinders that of the negative pressure downstream of the arbitrary actuatable Main throttle valve controlled the connection with increasing load between the float chamber and the area of the intake duct between the two throttle valves Has released valve cone. Considered publications:
German Patent Nos. ₁ 582722, 668515;
French Patent No. 1302 537;
French additional patent specification No. 46 567 (addition to French patent specification No. 790759), 1 sheet of drawings 809 629/1235 10.68 © Bundesdruckerei Berlin