US2039354A - Heavy oil carburetor - Google Patents

Description

May 5, 1936;

A. SEIDEL. 2,039,354

HEAVY OIL CARBURETOR Filed Aug. 14, 1955 2 Sheets-Sheet l I May 5, 1936.

A. SEIDEL HEAVY OIL CARBURETOR Patented May 5, 1936 UNITED STATES PATENT OFFICE Application August 14, 1933, Serial No. 685,070 In Germany March 10, 1931 13 Claims.

This invention relates to improvements in carburetors and more particularly to heavy oil carburetors.

A characteristic of the hitherto usual carburetors was to produce only a coarse atomizing "of the fuel-air mixture but not an ideal atomization thereof. This feature was not objectionable in the case of carburetors for light fuels, such as benzene, but it is impossible to obtain a sufficient heavy oil service with such carburetors because the imperfect atomization causes the formation of condensates, which enter into the cylinder and from the walls thereof into the crank case, where they produce a dilution of the lubricant. Consequently, if it was desired to use the cheaper heavy oil for driving internal combustion engines, hitherto it was necessary to use the so-called Diesel process, which, however, has the disadvantage of having about 2 times greater explosion pressures in comparison with carburetor engines. Therefore, the Diesel process requires larger dimensions of the engine so that the Diesel process is adapted practically for stationary engines only, and for motor vehicles and aircraft merely in certain exceptional cases.

The principal object of the invention is to provide an apparatus for atomizing liquid fuels at a high degree to permit heavy oil service.

Another object of the invention is to provide means to impart an exceptional high speed, such as more than 200 m/sec. to the fuel air mixture.

In order to carry out the invention, the following two arrangements (a and b) are used combined or individually.

(a) The main atomizer is controlled at its narrowest cross-section by means of a slot closure, to the splitting edges of which the primary mixture coming from injector slots likewise arranged at the narrowest cross-section of the atomizer flows continuously at right angles to the main air current coming from the open end of said main atomizer so that the actual maximum air speed and the actual maximum vacuum of the induction conduit prevail at said splitting edges for any throttling position of the charge control lever.

(b) The primary mixing channel branches into a plurality of ducts, each of which leads to a main atomizer arranged in one of a plurality of charge conduits for a multi-stage service, so that the several stages are supplied by a single fuel nozzle feeding the fuel mixture to said primary mixing channel.

The apparatus according to the invention is adapted to a high degree atomization of all fuels,

especially forheavy fuels (heavy oils), to which, however, it is by no means restricted.

The above mentioned objects and advantages as well as other objects and advantages will be more fully disclosed in the following specification reference being had to the accompanying drawings forming part of this specification, in which:

Fig. 1 shows the novel carburetor partly in a vertical sectional view and partly in a side elevation. 10

Fig. 2 is a section view. taken on line 22 of Figure 1.

Fig. 3 is a top plan view of the slot closure.

Figs. 4 and 5 show fragments of the slot closure in two working positions. 15

Fig. 6 is a horizontal sectional view through the carburetor similar to Fig. 2 but of a modified form of construction.

Fig. 7 is a top plan view of the slot closure of the carburettor according to Fig. 6.

The apparatus comprises a float chamber I for heavy fuel (heavy oil) and a float chamber 2 for light fuel (benzene), the two chambers being arranged in the same horizontal plane. The float chamber I for heavy oil has a nozzle 3, which opens into a channel 5 for the primary mixture in advance of a change-over valve 4. The float chamber 2 for the benzene has two nozzles 6 and 1, the nozzle 6 opening into a channel 8, which ends through the valve 4 in the channel 5 for the primary mixture. The nozzle 1 of the float chamber 2 for benzene serves for preparing the idle benzene-air mixture and ends in the channel 9 for the idle mixture.

The channel 5 for the primary mixture receives heavy oil-air or benzene-air mixture according to the position of the valve 4. The change-over valve 4 can also be so adjusted that the channel 5 receives a mixture of heavy oil-air and benzene-air mixture. Normally the changeover valve 4, which can be operated from the drivers seat, is in the position shown in Fig. 2.

It is, however, advisable to turn the valve 4 into the position in which the flow of the benzene is possible, but only until the engine has warmed up.

The primary mixing channel 5 branches into the ducts l0 and 10", which open into injector slots II and H" of the main atomizers l2 and [2 of the stages I and II of the carburetor. The atomizers l2 and I2" are controlled at their narrowest cross-section by a slot closure l3, l4, which will be hereinafter described. As can be seen from the drawings the single fuel nozzle 3 (or 6 when the valve 4 is reversed) supplies fuel to both the stages I and II through the primary mixing channel 5 and its ducts Ill and H. The nozzle 3 is so large, that its output is sufiicient when all the stages, in the example illustrated I and II, are open. However, the nozzle 3 is too large if only stage I is open, and it must consequently be compensated. This is effected according to the invention in that additional air is supplied to the fuel-air mixture fed only to the stage I by the atomizer 12' when the stage II is closed. This additional air enters through the duct H!" of the closed stage II, which duct communicates with the atmosphere through the injector slot l l" and the upper part of the atomizer I2 being open to atmosphere. The additional air, coming from the upper part of the atomizer 12" in the direction of the arrow I5, must flow through a Venturi nozzle I8 inserted in the duct 10" in a direction opposite the normal direction of flow, so that the additional air will be strongly throttled. If the ducts ID and I have similar cross sectional area, not 50% but less additional air will be supplied to the primary mixture flowing through the duct ID to the stage I, owing to the throttling of the Venturi nozzle. This measure of throttling, in conjunction with the automatic regulation of the quantity of additional air which will be hereinafter described, serves to equalize the disproportionate output of the fuel nozzle 3. The quantity of additional air passing through the duct I0" is determined by the pressure prevailing in the injector slot H. If the stage II is completely closed by the slot closure l3, I4, atmospheric pressure exists on the injector slot 1 l so that only as much additional air can flow "through the duct ID as the Venturi nozzle IS allows. During the opening of the stage II by means of the slot closure I 3, M, a gradually increasing vacuum is produced at the injector slot l l owing to the fact that the engine suction can .noW become effective over the stage II. Thus,

at first little additional air will fiow through the duct 10 into the channel 5, ID for the primary mixture as long as the stage II is completely closed, whereupon after the opening of the stage II the admission of additional air entirely ceases and finally the primary mixture is drawn by the engine also through the duct l0" and the atomizer nozzle l2 of the stage II. As soon as the stage II is completely open, the mixture flows uniformly through both stages, the cross-sectional areas of the ducts l0 and ID" being uniformly large. It must be noted that, during the opening of both stages, each of the ducts sucks undiluted mixture but that more mixture can never be drawn in than the channel for the primary mixture allows which is supplied by the nozzle 3 and is not larger than each of the two ducts l0, l0".

Owing to the peculiar arrangement just described it is ensured that the fuel-air mixture always flows into that induction stage of the main induction conduit in which the highest speed of flow prevails and consequently, when changing over from one stage to the other, that is during the additional opening or closing of the next following stage, no fuel condensates are produced. Moreover, a proportional fuel nozzle output is accomplished, which normally increases progressively in other carburetors.

As already mentioned, the two atomizers I2 and I2 are controlled at the narrowest cross section by a slot closure which consists of two very thin plates 13, M which slide with play in guides H and I8. The plates are oil-tightly enclosed and preferably lubricated by a wick lubricator I30.

The plates have holes [9, 20, 2|, 22 which control the channels of the stages I and If. The holes l9 and 20 are elongated. In Fig. 3 the slot closure is shown in closed condition, that is the holes E9 to 22 are situated relatively to each other so that the stages I and II are completely covered by the plates l3 and I4. When it is desired to open the carburetor, a rod 24 provided with a lever 23 is turned around its axis, so that the two-armed lever 25 mounted on its upper end is swung around its middle axis. On the free ends of this lever rollers 26, 21 are mounted which engage in cavities 28, 29 in the plates 13, I4 and shift these plates in their guides a distance corresponding with the amplitude of the oscillation of the lever. Although the plates I3, 14 slide with play in their guides, the plates in the position shown in Fig. 3, in which the stages I and II should be closed, will certainly not supply any wrong air because the plates, owing to their thinness are maintained air tight by the strong vacuum during idle operation. By the oscillating of the two-armed lever 25, the upper plate I3 is shifted in the direction of the arrow 30 by means of the roller 26 and the lower plate I4 in the opposite direction in the direction of the arrow Bl by means of the roller 21. In this manner the centres of the elongated holes [9, 20 are approached so that they first assume the position shown in Fig. 4. In this position the holes I9, 20 register so that a slot 32, somewhat in the shape of an ellipse, is formed, and in this manner the mouth of the atomizer I2 is at first liberated by this amount. During the further shifting of the plates relative to each other the holes come to the position shown in Fig. 5 and open fully the stage I. During the further shifting of the plates the holes 2| and 22 of the stage II at first overlap each other to such a degree that a slot corresponding to the slot 32 is produced, whereupon the holes 2| and 22 register entirely and open fully also the stage II. The stage I remains open during the whole opening operation as the holes [9 to- 22 are of oblong form as mentioned above. When the lever 23 is rocked in the opposite direction, these operations take place in inverse sequence.

By arranging the slot closure l3, l4 in the narrowest cross-section of the main atomizers l2, l2" of the two first register stages in which at the same time the injector slots II, I I" are situated, from which the primary fuel-air mixture is discharged, the following fundamentally novel effects for the degree of atomization of the fuel are obtained. In the case of horizontal arrangement of the plates l3 and I4 directly under the injection slot the fuel of the primary mixture flows simultaneously from all sides in a very thin layer to the splitting edges of the aperture slot of the slot closure. In the case of a very small opening of the slot closure, for example when starting up, the contour of the splitting up edges in the ellipse 32 is at least five times as great as the contour of an ordinary fuel nozzle with an aperture of about 1 mm. The air speed on the splitting edges is the actually absolute maximum air speed, which prevails in the induction conduit, contrary to the very imperfect air speed in the main atomizer of the hitherto used carburetor, in the case of slight opening of the throttle valve arranged behind the nozzle. The main nozzle in an ordinary carburetor, as is known, commences to operate at a vacuum of 3 mm.s water column=l/3333 atm. with the efiect that the fuel drops flow out of the nozzle very sluggishly so that there can be no question whatever of atomization. According to Venturi nozzle 36 of this conduit 33.

the invention, however, the actually maximum.

vacuum of the induction conduit which is important for good atomization prevails at the splitting edges of the slot even when opened to a minimum extent, which vacuum amounts to T 6 atm. as compared with 1/3333 of the carburetors hitherto generally used. Only in this manner is a very high degree of atomization ensured by the invention. These effects occur in any throttled position of the engine whilst fully preserving the proportion of fuel to air. Contrary to the invention the maintaining of a constant proportion of fuel to air can never be attained with the carburetors hitherto in use. If, for example with the known carburetors a standard fuel nozzle were to be placed in the maximum vacuum zone directly beside the slot, the fuel supply would always remain the same, whereas the quantity of air would vary according to how far the throttle valve is opened.

The conduits 33', 33" of the stages I and II terminate in a branch T-piece 34, to which the induction conduits 35 leading to the valve chambers are connected. The entire mixture conduit from the atomizer I2 to the valve chamber has an exceptionally small cross sectional area which in all the stages together amounts to about 43% of the cross sectional area of the conduit in a normal carburetor engine as hitherto employed. In this manner a very high mixture speed is attained, which enables a perfect atomization of the fuel. In the path along which the charge flows a plurality of atomizing means 36, 31, 38 are arranged, which narrow the cross-sectional area to 64% and thus likewise increase the mixture speed and assist in the atomization. The last atomizing means 38 is situated at the end of the induction conduit at the entrance to the valve chamber. The atomizing means constructed as Venturi nozzles, any number of which may be employed, fulfill the additional purpose of tearing off any condensates which may have deposited on the smooth wall of the conduits, preferably consisting of drawn copper pipes. For this purpose a very narrow annular groove 39 is provided around the nozzles, with the exception of the nozzle 36, which groove communicates with the narrowest cross section of the nozzle through injector slots 46. In this manner any condensates which may have deposited on the walls are torn therefrom by transversely directed air currents which are produced in the injector slots and supplied again to the mixture. Finally the construction of the atomizing means as Venturi nozzle also effects an absorption of the vibrations of the mixture columns coming from the valve chamber after the closing of the inlet valves of the engine. The atomizer Venturi nozzles also serve as gauge for the quantity of the fuel-air mixture which flows through.

As already mentioned above, the cross sectional area of the charge path 33', stage I, is only 18% of the cross-sectional area of the induction conduit of a modern high-speed engine with H. P. output per litre stroke volume. This small 18% cross sectional area is sufiicient in the case of modern American private cars for the cylinder charge, which allows a travelling speed up to 60 km/hr on the level. With this novel apparatus, as compared with the large induction width of the American engines generally used at the present time, more than five times the charge speed is attained in the stage I (conduit 33) and even 8.5 times the speed in the additionally fitted Consequently,the atomizing energy of the air current, amounts to 75 times the value of the energy attainable with the former carburetors up to a speedof GOkm/hour of the vehicle, as the atomizing energy increases by the square of the speed.

At the points at which the nozzles 3'! and 38, provided with an annular groove 39, are situated, the induction conduit is enlarged to accommodate itself to the size of this annular groove so that an unnecessary throttling is avoided.

The induction conduit extends for a short distance into the valve chamber and widens preferably in conical shape atits end in order to obtain less flow resistances. Moreover, it has on its lower end a slot or several holes 380., through which the fuel condensates, which collect on the bottom of the valve chambers, are sucked back into the induction conduit and through the atomizers during the repulse of the mixture column.

The atomizer nozzles 31, arranged directly behind the branch piece, have an important function to perform. When the suction of the engine takes place through another arm of the induction conduit, the vibrations of the mixture column are considerably absorbed in the dead arm of the induction conduit, because the mixture column must flow through the Venturi nozzle opposite to the normal direction of flow. Thus, critical vibrations of the mixture column are avoided. Further, the atomizers 31 are of greater importance than the final atomizers 38 for atomizing any fuel condensates deposited on the pipe walls because the sucking of the fuel into the air current is not yet sufficient for the atomization, and the splitting of the fuel drops and the atomization of the fuel take place only gradually along .a longer charge path behind the nozzles 31.

The entire induction conduit of the apparatus up to the valve chamber is exceptionally long for the purpose of attaining a good atomization. The length up to the T-piece 34 is about the same as the length of the branch conduit 35 behind the T-piece.

At the point 4| the mixture flowing at a high speed through the apparatus may be tempered by the exhaust gases of the engine or in any other manner. It is pointed out that this is not a heating for the purpose of atomization, as in the known heating carburetors.

The carburetor, as shown by the drawings, operates on the descending current principle.

As mentioned at the outset, the float chamber 2 for benzene has a nozzle 1, which serves for preparing the idle benzene-air mixture. This idle benzene-air mixture passes into the apparatus in accurately dosed proportion of fuel to air when the slot closure is completely or almost completely closed. The channel 9 branches into ducts 42' and 42", which are arranged below the level of the primary mixing channel 5 and open into the charge conduit of the stages I and II respectively through openings 43, 43 below the slot closure [3, M. The ducts 52M 12" and apertures 43', 43" are of such size that two thirds of the idle benzene-air mixture passes into the stage I and onethird into the stage II. By a higher percentage of benzene in the idle mixture in stage I better atomizing values are attained in the case of slight opening of the throttle element, for example when starting up the vehicle, because the heavy oil mixture combines intensively with the idle benzeneair mixture directly behind the throttling means.

In the formof construction illustrated in Figs. 1 .and 2 this idle benzene mixture passes continuously, in accurately dosed proportion, into the stages I and II even when the stages I and II are opened. In the latter instance the idle benzene mixture mixes intensively with the inflowing .heavy oil mixture, so that the atomization of the fuel air mixture taking place in the stage I is influenced very favorably and further a favorable transition from stage I to stage II is attained because, as already mentioned, a portion of the idle mixture flows to stage II. This idle benzene mixture can be maintained for any desired position of the throttling means, also for fully open position thereof. To accomplish this a separate channel 44 is provided, which forms the stage III and is i opened with the progressive opening of the slot closure or towards the end of the opening. As distinguished from the conduits 33, 33 the channel 44", conveys only pure additional air and has a cross sectional area amounting to about 15 to 20% of the total induction cross sectional area. By this arrangement not only the most economical fuel consumption is attained with the throttling means at fully open position but also a higher charging coefficient of the engine is obtained with relatively narrow cross-sectional area of stages I and II. The total of the cross-sectional areas of stages I, II and III is such that the calculated throttling cross sectional area, for exam ple 43%, is attained. The stage III is also controlled by the slot closure [3, I4. The upper end of the channel 44 of stage III branches into the two channels 44a and 441), which are controlled by apertures 45a, 46a and 45b, 46b in the slot closure. These apertures 45, 46 are arranged in such a manner that towards the end of the opening movement of the slot closure the stage III is opened.

In the form of construction according to Figs. 6 and 7 only two stages I and II are provided. In

'this instance the idle benzene mixture is automatically diluted and out off during the progressive opening of the slot closure. For this purpose channels 41' and 41" communicating with the atmosphere open into the channels 42' and 42" respectively and are exposed towards the end of the opening movement of the slot closure by apertures 48, 49 and 50, 5| arranged in said slot closure. On the lower part of the T-piece 34 a regulating screw 52 is provided. By unscrewing the same in the event of the failure of one of the valve needles on the nozzle 3, the excess fuel can flow off. The nozzle 52 also serves for regulating the additional air for the idle benzene mixture.

As already mentioned, it is possible, when run- 'ning on country roads and when the engine has warmed up, that is has attained its normal working temperature, to completely out out the benzene float chamber from the drivers seat by a cock not shown on the drawings. In this instance the existing change-over valve 4 can be employed as saving device for adjusting the most economical service when the engine is under any load. As the benzene main nozzle 6 is without fuel, the channel 8 may be employed exclusively as additional air channel by slightly shifting the valve 4. Consequently the finest adaptation to the atmospheric conditions (air density and temperature) is possible.

The above described forms of construction of an apparatus for atomizing fuels are only given by way of example. The elements mentioned in the different examples can be interchanged or other similar devices fitted without departing from the 1 general idea of the invention.

What I do claim as my invention and desire to secure by Letters Patent is:-

1. In an apparatus for atomizing liquid fuels the combination of a float chamber provided with a fuel nozzle, a primary mixing channel into which said fuel nozzle opens, a plurality of main atomizers for multi-stage service, a plurality of charging conduits forming said stages, throttling means for successively controlling said atomizers, each of said atomizers having an injector slot connected to said primary mixing channel by a duct and being open on one side to the air and on the other side connected to one of said charging conduits, the size of the single fuel nozzle being such that its output is sufficient when all stages are open together, while when only some of the stages are open the excess output is compensated by additional air from the duct of the closed stages communicating with the air.

2. In an apparatus for atomizing liquid fuels the combination of a float chamber provided with a fuel nozzle, a primary mixing channel into which said fuel nozzle opens, a plurality of main atomizers for multi-stage service, a plurality of charging conduits forming said stages, throttling means for successively controlling said atomizers, each of said atomizers having an injector slot connected to said primary mixing channel by a duct and being open on one side to the air and on the other side connected to one of said charging conduits, Venturi nozzles in each duct except the duct leading to the first stage arranged in a direction to permit free passage of the primary mixture but throttled passage of the compensating air coming from the atomizer and charging conduits extending from said main atomizer.

3. In an apparatus for atomizing liquid fuels in combination with the elements as claimed in claim 1, an additional float chamber provided with a fuel nozzle opening into a duct leading to the primary mixing channel and a change over element at the point of junction between said primary mixing channel and said duct, said point being between the end of the primary mixture channel open to atmosphere and the main atomwars.

4. In an apparatus for atomizing liquid fuels in combination with the elements claimed in claim 1 an additional float chamber provided with a fuel nozzle opening into a duct leading to the primary mixing channel, a change over element at the point of junction between said primary mixing channel and said duct, and a cock in the supply line of one of the fuel sources.

5. In an apparatus for atomizing liquid fuels in combination with the elements claimed in claim 1 a plurality of separated atomizers mounted beyond the main atomizers in the charging conduits, the last atomizer being mounted at the ends of said charging conduits.

6. In an apparatus for atomizing liquid fuels in combination with the elements claimed in claim 1 of a plurality of separated Venturi nozzles mounted beyond the main atomizers in the charging conduits, certain of said Venturi nozzles being provided with annular grooves and the charging conduits being of a width equal to the size of said annular grooves at the points at which said nozzles are inserted.

'7. In an apparatus for atomizing liquid fuels, the combination of a float chamber provided with a fuel nozzle, a primary mixing channel into which said fuel nozzle opens, a plurality of main atomizers for multi-stage service, a plurality of charging conduits forming said stages each main atomizer having an injector slot at its narrowest cross-section and being open on one side to the air and on the other side connected to one of the charging conduits, each injector slot being connected to said primary mixing channel by a duct, a slot closure in the narrowest cross-section of each main atomizer and provided with splitting edges, the longitudinal axis of each main atomizer being arranged substantially at a right angle to the longitudinal axis of said duct, whereby the flow of the primary mixture is deflected at said splitting edges, said charging conduits being widened at their end and provided with an aperture in the underside of their circumference.

8. In an apparatus for atomizing liquid fuels in combination with the elements claimed in claim 1, means for supplying idling mixture comprising a float chamber provided with a nozzle, a channel into which said nozzle opens, having branches opening beyond the slot closures in the charging conduits, the parts and the cross-sections of the branches being such that accurately admeasured, finished, idling mixture reaches the different conduits when the slot is closed and that the majority of the idling mixture enters the conduit constituting the first stage.

9. In an apparatus for atomizing liquid fuels the combination of a float chamber provided with a fuel nozzle, a primary mixing channel into which said fuel nozzle opens, a T-piece, a plurality of main atomizers for multi-stage se'rvice arranged in said T-piece successively controlled by a slot closure, a plurality of charging conduits arranged in said T-piece each of said atomizers communicating with one of said charging conduits and having an injector slot connected to said primary mixing channel by a duct, each of said charging conduits opening within the T- piece into a main conduit, said T-piece having an additional channel opening into said main conduit and on the other side being open to the air, said additional channel being controlled by said slot closure whereby pure additional air will be supplied towards the end of the opening of said slot closure.

10. In an apparatus for atomizing liquid fuels in combination with the elements claimed in claim 1 means for supplying idling mixture comprising a float chamber provided with a nozzle, a channel into which said nozzle opens, having branches opening beyond the slot closure in the charging conduits, said branches being connected to theair by ducts controlled by means of said slot closure, whereby during the progressive opening of the slot closure the idling mixture will be automatically diluted and shut off.

11. In an apparatus for atomizing liquid fuels in combination with the elements claimed in claim 1 a T-piece partly containing the charge conduits and a regulating screw in the lower end of said T-piece.

12. In an apparatus for atomizing liquid fuels the combination of a float chamber provided with a fuel nozzle, a primary mixing channel, into which said fuel nozzle opens, a charging conduit, a main atomizer having an injector slot at its narrowest cross-section and being open on one side to the air and on the other side connected to the charging conduit, said injector slot being connected to said primary mixing channel by a duct, and a slot closure inthe narrowest crosssection of the main atomizer and provided with splitting edges, the longitudinal axis of said main atomizer being arranged substantially at a right angle to the longitudinal axis of said duct, whereby the flow of the primary mixture is deflected at said splitting edges.

13. An apparatus for atomizing liquid fuels, as claimed in claim 1, in which said ducts connecting the injector slots with said primary mixing channel are of the same cross-section.

ARNOLD SELDEL.

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