US1399010A - Means for atomizing and igniting liquid fuel - Google Patents

Description

A. DOBLE.

MEANS FOR ATOMIZING AND |GN|T|NG LIQUID FUEL.

APPLICATION FILED FEB. 28, 1918.

Patented Dec. 6, 1921.

2 SHEETS-SHEET l.

A. DOBLE..

MEANS FOR ATOMIZING AND IGNITING. LIQUID FUEL.

APPLICATION FILED FEB. 28., F918.

Patented Dec. 6, 1921.

2 SHEETS-SHEET 2.

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` eren stares l msnm DOBLE, or DETROIT, MICHIGAN.

MEANS ron A'roNIzI'Ne AND IGNITING LIQUID rum..

Specication of Letters IIatent.

'iIPatented Dec. 6, 9211.,

Application tiled February 28, 1918. Serial No. 219,671.

To all/whom 1f/may concern: .i

Be it known that I, ABNER DoBIlE, a citizen of the United States of America, and resident of Detroit, Wayne county, \Michi an, have invented a certain new and useful lmprovement in Means for Atomizing and Igniting Liquid Fuel, of which the followin is a specification..

y invention relates to the art of burning heavy hydrocarbons which are non-volatile or substantially so at normal temperatures, and my invention comprises a means of instan'taneous ignition or initiation of combustion of such hydrocarbons in their normal tem erature condition.

invention has its application inconnectlon wtih the Iutilization of heavy hydrocarbons, such as kerosene and distillate, as fuel for the rapid generation of steam in the power-plant of steam-driven automobiles, wherein the elimination of the annoyance and delay of .pre-vaporization of the fuel and the rapid generation of steam are essential requisltes in a commercially successful automobile. v l

Heavy liquid hydrocarbons suchv as/kerosene can, as I have found in practice, be veryv eH'ectively and completely burned, without pre-heating or pre-vaporization, from an initially normal or so-called cold temperature condition and extremely high temperatures obtained for the generation of steam, by the atomization process of finely dividing the liquid and mixing it with the proper amount of air to support combustion and confining the combustion in a closed refractory chamber which attains an intense heat.

'.lhehydrocarbon at normal temperatures may be atomized Aor broken up and mixed with the proper proportion of air to com- .plete `combustion within said chamber, or the air which supports combustion may be used as the atomizing ,agency for finely dividing the hydrocarbon and projecting it into the combustion chamber. ln any event, however, there must be a sufficient proportion of air in the mixture to complete combustion in the combustion chamber, without anysmoke or soot whatever, else the very advantage attendant upon a utilization of the atomizing method in a steam-driven automobile ower-plant is lost. As before mentioned,

have found in practice that a mixture of the atomized fuel and air burned in a cham-l ber in the manner above mentioned can be completely consumed without soot and smoke, but such a mixture (which I will refer to, for convenience, as the main or completely combustible mixture), has a relatlvely excessive proportion of air and a relatively small proportion of atomized fuel. In

other words, relatively speaking, this mixture is rich in air and lean in hydrocarbon.

The extreme desirability in an automobile power-plant of instantaneous initiation of combustion of fuel and the use of an electric spark for this purpose, is at once obvious, but a mixture such as I have just described will not ignite at normal temperature by means of an electric spark, although after aving been properly ignited, it will sustain continuous combustion in said chamber. So far as l am able to ascertain, the failure of this mixture to ignite from a spark is due to the fact that a spark of lpractical proportions, although intensely hot, is comparatively small in volume, and in such a relatively lean mixture the particles of fuel are separated in a comparatively large volume of air to suchv an extent that the air absorbs the heat and prevents the transmission of heat to adjacent particles. from those i nited. Furthermore, if in addition the bo y of mixture is moving at comparatively high A velocity, the particles do not remain in the small zone 0f flame of the spark long enough to become ignited.

l have discovered, however, that a mixture of iinely divided vhydrocarbon and air at the normal atmospheric temperatures can readily be instantly ignited by an electric spark` if the mixture is excessive or rich in hydrocarbon and lean in air and thoroughly atomized to form a dense fog or cloud, but, on the other hand, a mixture of this character is not completely'combustible, there being insuiiicient air therein to entirely o-r completely consume the hydrocarbon which is so greatly in excess of the air supplied even under the most favorable conditions, hence such a mixture (which, for convenience of reference, l will term the auxiliary or .incompletely combustible mixture) is not adapted for continuous combustion purposes because it burns incompletely, is productive of smoke and soot, disagreeable odor and would not develop the necessary temperature if used in van automobile power-plant. As before mentioned, however, this mixture will readily and repeatedly ignite by an electric spark because, so far as I- am able to ascertain, the .particles of hydrocarbon are relatively close together and not diluted with air toany great extent; hence the heat generated by the spark, although small in without pre-vaporization, the instantaneous ignition of a completely combustible mixture at normal temperature for the sustained or continued production of heat by means of an electric spark, which result, in the case of an automobile power-plant, leaves nothing for the operator to do butto start the sparking and mixture forming mechanisms, and

-which in practice amounts to nothing more than the operation of an electric switch.

I accomplish these result-s by producing a main mixture of finely divided liquid normally non-volatile hydrocarbon and air in suiiicient proportions to completely burn this hydrocarbon, and a second incompletely combustible or auxiliary mixture of smaller volume, the second mixture being arranged in igniting relation to said main mixture, and in the zone of the auxiliary mixture I introduce an electric spark. The heat of the spark ignites the auxiliary mixture which transmits its flames to and ignites the main mixture. The flame of the auxiliary mixture need be maintained only for a sufficient period of time to bring about the ignition of the main fiame.

The object of my present invention is to provide an improved mixture-forming and ignition mechanism for automobile powerplants, which mechanism will produce a combustible liquid fuel mixture and will instantaneously ignite or initiate combustion in said mixture at normal temperature.

Other objects of my invention will appear hereinafter.'

The accompanying drawings illustrate an automobile power-plant structure which embodies my invention and which accomplishes the desired results. r

In the drawings:-

Figure 1 is a sectional view through the blower, a portion of the combustion chamber, and one of the atomizers of the fuelspraying, mixture-forming and ignition mechanism embodying my invention;

Fig. 2 is a transverse sectional view of the structure shown in Fig. 1, taken substantially on the line 2-2 of Fig. 1;

Fig. 3 is an enlarged detail section of the fuel nozzles for producing the different mixtures of fuel and air;

Fig. 4 is a view in diagram illustrating my improved structure and control system4 therefor, as arranged for use-in a steam driven automobile power-plant. l

. The structure shown in the drawings involves a blower 10 of any suitable type capable of supplying large volume of air at' comparativelyloW pressure for the purpose of atomizing or breaking up the liquid fuel and forming therewith the completely combustible or main mixture to which I have referred. This blower has a fan or blade wheel 11 rotating within a casing 124 and driven by means of an electric motor 13 mounted on the blower casing. The blower has its outlet 14'divided into two sectionsjl extending horizontally and in parallel relation and the ends of these sections .are removably fastened to the wall 16 of the inclosure within which is positioned the fire-pot 16a forming the combustion chamber. The

combustion chamber is shown in position beneath a steam generator 16b of an automobile power-plant, this chamber being arranged to lnclose the lower end of the generator casing 4so that the heated products of combustion will rise directly in said generator. The end portions of the blower outlet sections are tubular and contain removable Venturi tubes or members 17, and within the combustion chamber there 1s provided a casting 18 having two tapered passages 19 which are alinecl with and form continuations of the Venturi tubes, to direct the s'prays of fuel mixture into the combustion chamber. The Venturi tubes are of course tapered to a restricted throat portion 171so as to increase the velocity ofthe air passing therethrough and at these throat portions are fuel nozzles which supply the fuel to be atomized. These fuel nozzles are formed by the small Venturi tubes 2O mounted upon upstanding posts 21 on a common manifold member 22. The A fuel is admitted to these tapered passages through the openings 23 in the upper sides, these openings communicating with the annular passages 24 formed by grooves on the outer surface of the nozzle tubes. The upper ends of the posts have rings which support the nozzle tubes and close the annular passages, and these posts also have passages 25 which convey the fuel from the manifold passage 26 to the nozzles. At one end of the manifold, I mount a float chamber 27 which may be of any suitable type, for the purpose of maintaining the liquid fuel at the proper level in the fuel nozzles. The liquid fuel is carried in a suitable tank 29, which in practice ismounted on the automobile frame at a point somewhat below the fuel nozzles, and, in order to raise the fuel to the float chamber through the feed pipe 30, I provide air pressure of a few pounds in the tank.

This pressure is supplied b 'a hand-pum 31 connected by pipe 32 wi the fuel tan above the level of the oil..4 The blower, as before mentioned, provides a constant blast or current of air. through each ofthe Venturi assages, and, in accordance with the principles of atomization, draws the liquid fuel froxnthe nozzles and finely divides it, a portion of thecurrent of air being diverted through the small nozzle passages to assist in breaking up the fuel, thus producing sprays of fuel from the nozzles, which at the ends of the nozzle tubes is mixed with great volumes of air. This action produces a mixture of fuel and air in such proportions as to support complete combustion in the fire-pot. A dilute mixture of this character wherein there is a proper proportion of air to support complete combustion will burn without soot, smoke or odor, and will supply the volume of heat necessary for the rapid generation of steam, and can be easily controlled after having been ignited, but such a mixture is entirely incapable of being ignited at normal temperature by the small liame of. an electric spark or equivalent ignition means of practical proportions and of instantaneous operation. I therefore arrange the structure so that it will also produce a diferent mixture of fuel and air which is capable of ignition by an electric spark, and the llame of this spark-ignitible mixture is utilized for the ignition of the main combustible mixture. l'. accomplish this by the provision of supplemental nozzles 34 which are positioned to direct a small volume of high pressure air in the form of a fine jet into the main nozzles, thereby aspirating a sufiicient'increase in the amount of liquid fuel to be atomized, to enrich or superimpose upon the main mixture at the main nozzles a properly atomized dense fog or rich mixture which is capable of instantaneous ignition by an electric spark or its equivalent.

For the purpose of conveniently obtaining suiiicient pressure for the air -jets,l utilize the compressed air in the fuel tank. Under these conditions, the sprays of fuel mixture at the main nozzles are of such proportion that they will readily ignite from a cold condition by a spark, and the ames from the burning sprays will instantly i nite the mixture produced by the blower air and main nozzles. The spark for ignition purposes takes place between the electrodes 35 and 36, just within the ends of the main nozzle tube passages. rlhe electrodes 35 are formed by projections in the main nozzles which are suitably grounded at 37, while the other electrodes 36 are carried by spark plugs 38, screwed into the Venturi tube members and connected to the secondary winding 39 of a suitable spark coil by means of the conductors 40..

`The mixture which is thus produced and which is capable of spark ignition, however, is incompletely combustible and can- `relatively small as compared with the main sprays, and, if not continued too long, its smoke and soot will be consumed in the combustion chamber. As a matter of practice, the duration of the ignition mixture need be but momentary, because the matter of time from the initiation of the spark until the main sprays become ignited ispractically instantaneous. For these reasons, it is advisable to maintain the ignition mixture for veryshort periods of time when required to ignite the main mixtures, and inl Fig. 4 I illustrate a controlling systemwhich `automatically'determines the period of duration of the ignition flame and spark igniter. The controlling mechanism involves an air storage reservoir 44 capable of holding a charge of air under' pressure sufficient to operate the air jets for the proper period of time. This reservoir is illustrated as larger than the fuel tank for the sake of clearness of illustration, but it will be understood that in practice it is smaller and of considerably less capacity than the fuel tank, the fuel tank being capable of holding suflicient compressed air to charge the reservoir many times. The reservoir has a passage 45 connected by pipe 46 with the compressed air supply in the fuel tank, and this passage is controlled by a valve 47 at one end of the valve stem 48. This valve is maintained normally open to keep the reservoir supplied with air by means of the spring 49. A pipe 50 leads from the reservoir to the air jets 34, and the reservoir outlet is controlled by a valve 51 on the lower end of the valve stem 48, this valve being normallyclosed by the spring 49.V When the lower valve is opened and the upper valve closed, the charge of air in' the reservoir will operate the atomizer 34 until the charge of air is dissipated, whereupon the high pressure air will be cut off from these air jets. rl'Che valve stem is operated by a solenoid 55 which is `controlled by an operators switch 56. The current for this ma net is supplied from a grounded battery 5%, over the circuit conductors 58, 59 and 60 to ground.' The valve stem also carries a switch member 61 which closes the motor circuit 62 through the contacts 63, so that, when the operator closes nism and blower will b e started simultaneously. In the event that the air pressure in the reservoir 44 or fuel tank 29 should fail and prevent the operation of theignition mechanism, it is not advisable to startthe main atomizers and fill the combustion chamber with fuel; hence a diaphragm the manual switch 56, the ignition mechaswitch 64 is provided which is subject to the air pressure in the reservoir 44 and which normally holds the circuit of the solenoid closed at the contact 65. Of course, if no air pressure exists in the supply, the contact is held open and the operators switch has no effect on the system. The circuit 66,

,which includes the primary winding 67 of the spark coil is also controlled by a diaphragm switch 68 similar to the switch 64, so that, while pressure exists in the reservoir 44, the spark coil circuit is closed, but, when the charge of air'has been exhausted, this circuit is opened and the spark discontinued simultaneously with the discontinuance of the pressure air to the supplemental air nozzles 34. The control system which I have herein described constitutes the subjectmatter of my co-pending application serial N o. 178,513, filed July 3, 1917.

I claim:

1. The combination of a main Venturi tube, an auxiliary venturi including a fuel nozzle, in said main venturi, a supplemental nozzle arranged to project a jet of high pressure air in said auxiliary venturi, an ignition device for igniting the spray formed by said supplemental nozzle, means for supplying air under pressure to said supplemental nozzle, and an air blower for supplysure air into said venturiat a point adjacent said fuel nozzle, means independent of said air blower for supplying high pressure air to said supplemental air nozzle, and an igniting devi'celfor igniting the spray formed by said supplemental air nozzle.

3. The combination of a blower having a Venturi tube outlet, a liquid fuel nozzle positioned in said venturi in aspirating relation to the air produced by said blower to form a completely combustile mixture, a supplemental nozzle for projecting an independent fuel nozzle tov produce an incompletely combustible mixture, an ignitingV device for igniting said incompletely combustible mixture, and means for momentarily supplying pressure air to said supplemental nozzle.

`Signed by me at Detroit, Mich., this 25 day of Feb., 1918.

ABNER DOBLE.

stream of high pressure a1r into said liquid

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