US1433689A - Carburetor - Google Patents

Description

.1.1. TRACY AND L. H. MORSE.

CARBUHETOR.

APPLxcATloN FILED MAR, 8. 191e.

Patented 0013. 3l, 1922...

2 SHEETS-SHEET l.

TTQfe/mm.

J. J. TRACY AND L. H. MORSE.

CARBURETOR. APPLICATION FILED MAR. 8,1918.

Patented Unt. 31, 1922.

Uufrl) STATE-s PATENT FFICE.

JAMES J'. TRACY AND LAWRENCE H. MORSE, OF CLEVELAND, OHIO; SAID MORSE ASSIGNOR T0 SAID TRACY.

CARBURETOR.

Application led March 8, 1918. Serial N0. 221,108.

To all whom t may camera.'

Be it known that we, JAMES J. TRACY and LAWRENCE H. MORSE, citizens of the United States, and residents of Cleveland, countyof Cuyahoga, State of Ohio, have jointly 1nvented a new and useful Improvement in Carburetors, of whichv the following is a specification, the principle of the invention being herein explained and the best mode in which we have. contemplated applying that principle, so 'as to distinguish it from other inventions.

The present invention has as its object the provision of a carburetor, in which the character of the charge, or mixture, is properly cont-rolled to meet variations in the temperature of the air as it is drawn into the carburetor. A further object is to provide for the maintenance of a uniform temperature in such air under normal operating conditions. In other words, the rst feature of control functions lduring the starting stage when only relatively cold air is available, but under normal operating conditions, it is contemplated that pre-heated air will be available and that by cont-rolling the temperature of such air, the setting of the carburetor parts for varying the mixture will remain practically constant.

To the accomplishment of the foregoingr and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims, the annexed drawings and the following description setting forth in detail certain mechanism embodying the invention, such disclosed means constituting, however` but several of the various mechanical forms in which the principle of the invention may be used.

ln said annexed drawings:

Fig. 1 is a vertical sectional central view of one form of the carburetor embodying our present improvements; Fig. 2 is a vertif, cal section of a portion of said carburetor taken at right angles to the. plane of Fig. l as indicated by the line 2-2 thereon; Fig. 3 is a horizontal sectional view of the same device with the indicated by the is a vertical sectional central view similar to that of Fig. 1, but illustrating a modified. form of construction; and Fig. 5 is a sec line 3 3, Fig. 1; Fig. 4

plane vof the section beingl tional view of a detail of the latter showing parts in different operative positions.

The carburetor, in connection with which our present improvements are shown in the aforesaid drawings, belongs to that type wherein the air friction, or flow of air drawn through the device by the suction ofthe engine, is relied upon to open and regulate not only such flow of air, butalso the flow of the hydrocarbon fuel which is mixed therewith to form the charge proper. More specifically still, the construction of the carburetor, proper, in both the modied forms of the present invention is substantially the same as that described and claimed in our co-pending application, filed June 30, 1916, Serial No. 106,777, Ie-iiled April 8, 1918, Serial No. 227,400. Accordingly, so far as similar parts occur in Figs. 1 and 4, sluch parts will be designated .by like numera s.

Referring first of all to the construction illustrated in Figs. 1 to 3, inclusive, the body of the device will be seen to consist of a tubular casing 1 provided with an air inlet. opening 2 and an outlet opening 3. Such outlet opening is, of course, connected to the engine manifold, as need not be further explained, and is controlled by a throttle in the form of a butterfly valve 4 of usual construction, carried by an oscillatory shaft 5 transversely mounted in such outlet opening and provided with suitable operating means (not shown). The inlet opening 2 is designed to be connected with a suitable heating arrangement (not shown wherein the exhaust gases from the engine or other heat source are utilized as the heating agent, as need not be explained in detail.

Rising centrally from the bottom of the casing 1 is a fuel-supply duct or nozzle 10, in the upper part of which is fitted a 'nozzle proper 11, that has enlarged head 12 of a diameter substantially equal to the external diameter ofsaid duct. The upper portion in hand as leading from a float-chamber 16, wherein the height of the liquid fuel is controlled by means of a float 17, as will be readily understood.

Surrounding the end of the nozzle l1, so as to be freely slidable thereon, is an annular valve 25 that serves to partially ll the annular space between the duct and the surrounding casing Wall. This valve is adapted to be raised from its normal position (somewhat lower than illustrated in Fig. l) to the position thus illustrated, or to a higher position, by

means of a rocker 26 mounted in the lower portion of the casing and to one side ofl said nozzle 10, said rocker being connected to said valve by a. link 27. This rocker is carried by a transverse. shaft 28, one end of Which projects without the easing, and is provided with a lever 29 and link 30 for the purpose o f manually 'controlling the setting of said valve 25, in a fashion that Will be hereinafter fully described.

Centrally disposed in the upper portion of the casing 1, being held there by means of radial arms 31, is a cylindrical chamber 32 that serves as a dash-pot to receive the upper piston-like projection 33 of a. second annular valve 34, which, in t-he normal position of the valve illustrated in Fig. 1` surrounds the first-named annular valve 25, and substantially shuts off communication between the upper and lower portions of the casing. A predetermined vertical movement of this valve 34, however, will leave an annular opening, aswill be obvious, the size of such opening increasing as the valve continues its upward movement, while the point at which the opening first occurs, depends upon the setting of the annular valve'25. The pistonlike portion 33 is spaced from the valve propel', and at the same time attached thereto, by means of radial arms 35, between which the air is free to pass when the valve is raised, as just described.

Centrally mounted in the piston portion 33 of the annular air valve 3l is vet another valve 38, which controls the opening in the fuel-supply nozzle 11. The body of this valve 38 is coned on its under side to tit the beveled discharge orifice 18 'in nozzle 12, and

-is further provided with a relatively adjustable spindle or needle-valve extension 39 threaded in said body and adapted to pro-- ject within the bore 14 of the nozzle, such extension being tapered. as shown in Fig. 1. This fuel valve is not rigidly mounted in the piston portion of valve 34, but is vertically reciprocable relatively thereto, a spring 40 serving to maintain it in normal posit-ion. but allowing it to have a certain amount of play, in order to insure that it will properly center itself in the nozzle.

In addition to the means, including` thc lever 29 and link 30 connected with the rockduct l() and the ,upperv shaft 28 for manually positioning or settingr` the inner annular valve 25 that surrounds the nozzle, we provide a. thermostatic device that is adapted to modify such settingr as the temperat-ure of the air drawn into the easing 1 varies.

1n the form illustrated in Figs. 1 to 2), this device consists of a short corrugated tube 45 filled with a suitable Huid, so as to elongate axially as the temperature rises and shorten as the temperature falls. One end of this element is fixedly attached to the side Wall of the casing 1, while the other end is connected to a second rocker 4G loosely mounted on the shaft. This rocker 46 is in the form of `a yoke that is adapted to engage with an extension 47 of the rocker 26. Normally the weigl'it of the valve 25 which may be supplemented by a suitable. spring if desired will be sufficient to maintain said rocker 26 thus in engagement with said lvoke` the result being that, as the thermostatic element expands, the yoke turns toward the right, as shown in Fig. 1, and the valve 25 will gradually drop, or assume a lower and lower position, with respect to the supplyfuel nozzle.

The manual raising of the valve 25. in order to provide the necessary rich mixture on starting up the engine, is, of course, in no wise interfered with by the presence of this tliermostatic controlling element and the. operation'just described, lult as soon as thc rock-shaft 28 is left free, the position of the' valve 25 is determined by such thcrmostatic device.

As has been previously explained. when a temperature is reached 'where complete vapor-ization of the liquid fuel results. it is desirable to maintain the temperature of the air supplied to the carburetor at a. constant point. Ye accordingly provide a` supplemental air inlet opening 5() in the lcasing l. such opening communicating directly with the atmosphere, or, in other words, having no connection with anyheating apparatus as has the main inlet opening 2. This supplcmental air inlet opening is normally closed -by a suitable valve 51. but is adapted to be opened, when the temperature of theI air drawn into the casing reaches a predetermined point, by means of a second thermostatic element 52 similar to the one just described, such element having a lost motion connection with the valve, so as to lift it from its seat only after it has expanded a certain amount.

The general operation of the device as now described in full should be readily understood. Normally, the outer annular airvalve 34 will be in the position shown `in Fig. 1. In order to start, the inner valve 25 will be manually raised to a point somewhat higher than indicated in said figure, the effect of cranking the engine being to raise the outer valve by the suction induced until it clears the inner valve. rlhe fuel supply valve 38 will be raised correspondingly high and thus provide a rich mixture, as is desirable in starting. As soon, however, as the engine is started and the manual control released, the inner valve 25 drops until the extension 47 on the rocker 26 engages with the thermostatically controlled yoke 46. The outer valve 34, together with the fuel valve, will dro a corresponding amount, andas the air rawn into the inlet opening 2 becomes heated, the thermostatic element 45 will allow the valves in question to drop still lower, correspondingly reducing the roportion of fuel tothe volume of air eingdrawn in. When the temperature of such air reaches the desired point, its furf ther rise will be checked by the action of the second thermostatic element 52 in raising the valve 51 from its seat, so as to open the supplemental air inlet opening 50. Upon this device becoming thus operative, there will, under normal conditions, be no further action on the part of the first thermostatic device; the sett-ing of the inner annular valve, in other words, remains fixed under such condition.

lt will be noted that, as shown in Figs. 1 and 4, only a slight space is left'between the two annular valves to provide an easy working fit; also that the upper portion of the bore of the inner annular valve is enlarged so as to leave an annular space 53 between the same and the fuel-supply duct and nozzle, this space 53 being connected by means of a series of apertures 54 with the lower portion of the casing. v

In the modified construct-ion illustrated in Fig. 4, the construction and operation of the carburetor proper is substantiallv identical with that just described, except that instead of utilizing a float chamber to maintain the fuel at a predetermined level in thenozzle, we here illustrate the use of a direct connection 55 with the source of fuel supply, the admission of the fuel into the nozzle being controlled by a weighted valve in the form of a plunger 56, that has its lower end coned to conform with an upwardly facing seat 57 in the lower end of the nozzle.

rllhe connections, however, between the manually operable rock-shaft 28 and the inner annular valve 25 are of different construction from that previously described, in order to utilize a thermostatic element of a different form, viz, a. strip of' so-called thermostatic metal instead of a hollow corrugated tube. As known in the art, such thermostatic metal is a composite bi-me tallic article made up of two metals of relatively diiferent co-eificients of expansion, these being securely united to form mechanically a metallic strip or b-ar. Assuming that such a.bar is approximately straight at a normal temperature, a rise in temperature will cause the same to bend in a predetermined direction, the amount of the bending being proportionate to the change in temperature.

Accordingly, instead of directly connecting the valve 25 by means of links to a rocker on the shaft 28, in the construction in hand we extend such rocker 60 in the opposite direction, and rigidly attach to the outer end of the same one end of a bar 61 ot' such thermostatic metal, the layer having thel higher co-efficient of expansion being disposed upwardly. -The upper end of this bar is then connected by short links 62 with thel valve in question. It being understood that the bar is suiiiciently rigid, so as not to flex appreciably other than under the influence of a change in temperature, it .will follow'that manual setting of the valve may be hadr just as in the other construction. However, upon releasing the manual control and the rock-shaft coming to a position of rest against a stop 63 (for example) any change in the temperature of the incoming air will cause the thermostat-ic bar to ben or bow in the fashion indicate-d in Fig. 5, so as to cause its inner end to occupy a relatively lower position and thereby corresoondingly to lower the inner annular valve. Should the air, on the contrary, grow colder, the bar will bend in the opposite direction so as to raise the annular valve.

This same type of thermostatic element may be utilized to admit a supplemental supply of coldair, in order to prevent. the temperature of the air as mixedk with the fuel from rising too high. As illustrated in Fig. 4. a pair of oppositely disposed supplemental air inlet openings 65 are formed in the casing adjacent the main air inlet opening 2, through which pre-heated air is designed to be drawn, and a pair of correspondingly facing valves 66, mounted on a com- Inon stem 67, are provided to close these openings. balanced e'ect is obviously secured, the stem 67 being guided in a suitable bearing 68 formed in a bar-extending transversely of the casing.- Rigidly attached at one end to the side wall of the casing is a thermostatic bar 69 of the same sort as the one previously described, the other end of such bar being provided with a fork 70, or otherwise'formed to engage a pin 71 in the stem of the valve, and thereby raise the lat-l ter whenever the air reaches a predetermined temperature. lln this way, a certain amount of colder air is admitted and the mixture maintained approximately at a uniform temperature during the further operation of the engine.

As previously indicated, the temperature which it is desirable thus to maintain con'- stant. is that at which complete vaporization of the fuel occurs, there being a loss in going to makeup the mixture should bey vdifferently proportioned, that is, the setting of the valve 25 under the action of the ther- ,mostat must now be different from that previously required.' We have found, in other words, that the action of the thermostatic element 61 must be checked, once such a temperature is reached. More specifically, if the mixture is not to be rarified to too great an extent, the action of such thermostat must be reduced approximately one-half. This result is' very simply secured in the construction under consideration by providing a projection midway between the ends of the rocker 60 wherewith the thermostatic element 61 contacts, when it is bent or bowed a predetermined amount, corresponding with the critical temperature. This projection conveniently takes the form of a set screw 72, so that adjustment may be had in this particular. y

Otherwise than as just indicated, the general mode of operation of this modified form is the same as the one first described above.

Other modes of applying the principle of our invention may be employed instead of the ones explained, change being made as regards the mechanism herein disclosed, provided the" means stated by any of the following claims or the equivalent of such stated means be employed.

However, if

We therefore particularly point out and distinctly claim as our invention 1. `In a charge-forming device, the combination of a suitable casing having an outlet for the charge and an-air-inlet; a frel nozzle discharging within said casing; two valves co-operating to substantially close the passage through said casing, one of said valves being adapted to be moved by the suction of the engine; a thermostat mounted in the air inlet portion of said casing and arranged to be affected by the temperature of the air admitted to said casing and adapted to operate the other of said valves;v and' a. third valve, operated by said suction-actuated valve, for controlling the supply of fuel to said nozzle.

2. In a charge-forming device, the combination of a suitable casing having an outlet for the charge and an air-inlet; a fuel nozzle discharglng' within said casing; two valves co-operating to substantially close the passage through said casing, one of said valves being adapted to be moved by the suction ofthe engine; a thermostat mounted in the air inlet portion of said casing and arranged to be affected by the temperature of the air admitted to said casing and ,l

adapted to operate the other of said valves; external means for operating said other valve independently of said thermostat; and a third valve, operated by said suction-actuated valve, for controlling the supply of fuel to said nozzle.

Signed by us, this 6th day of March, 1918.

JAMES J. TRACY. LAWRENCE H. MORSE.

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