US1716988A - Carburetor - Google Patents

Description

CARBURETOR Filed Jan. 28, 1927 2 Sheets-Sheet 1 //V VEN Toe 60/00 ccoxv/ 74 r roe/var June 11, 1929.

G. TACCONI CARBURETOR Filed Jan. 28, 1927 2 Sheets-Sheet //v VE/Y Toe 60/00 AC v ATTO/E/YEY Patented June. 11, 1929.

UNITED STATES 1,716,988 PATENT OFFICE.

sumo. raccoin, or memoir, ITALY.

. oanrunm'on Application filed January 28, 1927, Serial No. 164,241, and in- Italy I'ebruary 8; 1m.

The present specification has for its object a carburetor for internal combustion motors, wherein the composition of the. mixture of volatile liquid and air is rendered substan- 5 tially constant regardless of the speeds,

loads or stresses to which the motor is sub jeeted, and without any correction by hand.

A modification moreover ensures a quick pick-up and a manually operated device allows of an adjustment. being applied to correct for variations of the barometrical pressure due to the varying altitudes at which the apparatus is'required to function.

In order to understand the principle whereupon said invention is based it is well to bear in mind that in an ordina carburetor 'an excess of fuel obtains at high speeds of the motor and a deficiency of fuel obtains at low speeds, this being due to the diverse nature of the two fluids constituting the r(ni xt)ure, the one liquid fuel the other gaseous air According to the present invention this drawback is done away with as the carburetor generates two gaseous currents which are mixed in such manner as to secure perfect compensation and hence a mixture that is in the highest degree homogeneous.

The apparatus is also provided with means for effecting the necessary corrections in motors for aviation purposes, which are exposed to considerable barometrical variations due to the difierent altitudes.

The annexed drawingsdiagrammatically show practical examples. of the invention.

Fig. 1 shows a section through a carburetor according to the invention, Fig. 2 is an enlarged View of the adjust; ing mechanism shown in Fig. 1.

i 3 shows-the adjusting mechanism in a difi erent position.

Fig. 4 shows a modification. Fig. 5 shows a further modification. Fig. 6 is a detail view of the adjusting plug of the carburetor as shown in Fig. 5.

- As is apparent from'Fig. 1 of the annexed drawings, in the carburetor according to the "invention, we have the usual constant level tank a. In the body ?5 of the carburotor is formed a chamber, which is preferably cylindrical. In this chamber are located the butterflywalve c and a Venturi tube d as well a sa regulating air intake passage e, communicating at one end with atmosphere and at the other end .with a-secondary mixing chamber f-. A nozzle -h .the conduit supplies a mixture of atomized and vaporlzed fuel to the conduit g which acts as a primary mixing chamber, and at its other end communicates with the atmosphere through the air intake '13.

Intake passage e has been termed int of fact a part of the air passing througlh the' passage e passes directly throug the Venturi tube, but a art of the stream, owing to its impact against the conical surface -f generates a whirling movement in the mixing chamber fsuch as to cause the pressure in conduit -gto vary with the speed of the motor insuch mannenas to vary the ratio of the flow from -g to the flow through -'e and thus to automatically ad ust the richness of the mixture to the speed-of the motor.

The device intended to ensure an economical running of the motor acting solely on the performance of delive of the air intake passage,-is shown in Flgs. 2 and 3 drawn to an enlarged scale, by the letters 'The adjustingplug g is rotatably mounted and is provlded with a longitudinal aperture o' and communicates with -g through the orifice e. This orifice amay be oriented, by rotating the adjusting plu so as to open either in the direction of t e' movement of the fluid, (Fig. 3 flowing through the o0ngpit gor in t e opposite direction, (Fig. When the orificetais oriented as shown in Figs. 1 and 3 the fluid entering through the orifice t and following the path mdieated by the arrows, is discharged through v+ and -s-- into the tube -g.

When the orifice e is turned in the opposite direction, however, the fluid enters the adjusting plug g through the orifices- 't and -s-, and passes throu h the conduits v-,'r', and -u to t e conduit -g-. 'The result is to increase the flow through g-'- which acts upon the nozzle h' in such a manner as to reduce the output thereof.

The adjustment for running at'minimum speed is brought about by'one of the customary devices in use on carburetors for explosion motors.

At slow speeds of the motor the conduits. are filled with a mixture of atomized and vaporized fuel supplied by the nozzle -hwhichis located at a suitable level relative to the level of the liquid in the tank.

011 a somewhat rapid opening of the butterfly Valve the flow of air through the orifice -t or the orifices tands, according to the orientation of the adjusting plug, draws the atomized fuel and fuel vapor along the path marked by the arrows in either of the cases, the effect being toinsure an excess of fuel such as to allow of a quick acceleration.

Fig. 4 represe nts a modification of the carburetor accordlng to Fig. 1 as regards constructionaldetails, but still in accordance with the principle underlying this invention.

In the modified form likewise, a conduit g is to be noted wherein therich mixture is produced; "as well as a regulating air nozzle e-; a mixing chamber --f and a venturi d''.

In this case the mixture, excessively rich, but already corrected, as regards the constancy of its constituent proportions, by the regulatng air nozzle e, is discharged into the constructed portion of' a venturi d where it mixes with the air as indicated by the arrows. i

- As to the mode of functioning reference should be had to the description hereinbefore' set forth for the first case accord to Figs. 1, 2 and 3. v 1

In the carburetor according to Fig. 5a calibrated injector nozzle -2 has been added in the regulating air nozzle e-' with a corresponding small tube "to' for 'the sole purpose of facilitating the recuperation and in order the better to diffuse the volatile combustible liquid in the air during operation at-mean speeds.

In this device likewise, as inthe foregoing according to Fig. 1 compensation is attained in the same way,-withthe sole difference that in the former the regulating nozzles eonly delivers air, Whilst in the. latter the regulating nozzle delivers poor mixture. Of course, in this second device the .extent of delivery of the two'nozzle's h and --2 is so reglated that the sum thereof shall equal the delivery of the nozzle 7:r shown in Fig. 1.

The modification (whereby the carburetor is adapted to air-craft motors) brought about in theplug -g for the correction of'the mixture in orderto enable the variation of the efiiux of combustible liquid also in relation to the different harometrical pressures is as follows The constant leveltank -.a is closed against the atmos 'pheric pressure and by means of the orifice sition s is conveyed thereto either the dynamic pres sure, if the-orifice -ais orientated in a direction opposed to that of the fluid streams in g as in Fig. 6, or the static pressure ware diametrically opposed, although they are not at the same level, their effects will be aggregated, so that the carburetor is capable of considerable variations in the supply of fuel from the nozzles -h and -2-, which condition is necessary for aviation motors.

In order to have the nozzles .2-- and h' supply a maximum amountof fuel,

Therefore, as the two orifices sand' the opening will have to be ina position facing the inflowing air asshown in. f Flg. 6.

a consequence, the dynamic pressure of the inflowing air will be communicated to the tank -a through the passages and -2 and the resulting pressure will of course tend to assist in forein the fuel out of the nozzles 2--- and Also, the air extendin through the orifice twill be discharge through the opening s decreasing the pressure acting on the nozzles.

When it is desired to have the nozzles eject a minimum amount of fuel, the adjusti'ng plug is turned through 180 to the popressure in tank -ais materially reduced as only the staticpressure within the conduit -g.-is communicated to it. This in itself produces a material reduction in the output of the nozzles and the eflect is further accentuated by virtue of the fact that theair entering through tcannot pass out through the adjusting plug -gand the pressure acting against the nozzles is accordingly raised.

A wide variation in the amount of fuel supplied by the nozzles may thus be ,obtained by manipulation of the adjusting P s 11% The devlce for operation at slow speeds is composed of theftube -7 the injector nozzle 8- and cap -9- wiiich function in the well-known manner.

It should be understood that the formsv own in Fig.v 5. In this case the showing of the improvements concerned, it,-

being possible to vary the form of their practical execution without departing from the scope of the concept underlying the invention taken as a whole.

Claims:

' 1. A carburetor comprising anair conair conduit, a pnmary mlxing chamber discharging trans'versel into the secondary mixing chamber an having an air inlet, a b -pass having an air inlet connected to sai primary mixing chamber and also a mixture outlet dischargin into said 'primary mixing chamber, a f i iel nozzle in the by-pass, and means effecting communication between the said primary mixing chamber and the by-pass and controllably acting as an air inlet for said by-pass or a mixture outlet therefrom.

'2. A carburetor comprising an air conduit, a secondary mixing chamber in-said air' conduit, a primary mixing chamber having an air inlet and an outlet discharging transversely into the secondary mixing chamber, a 'U-shaped by-pass having an air inlet opening communicating with the primary mixing chamber and a mixture outlet discharging into said primary 'mixing chamber, a fuel nozzle in'the by-pass, a rotatable adjusting plu mounted in one end of the b -pass, said a justing plug having a longitu inal passage extending to its lower v end and having an opening in said primary mixing chamber beyond the end of. the bypass in which it is mounted.

3. A carburetor comprising an 'air conduit, a secondary mixing chamber in said air conduit, a primary mixing chamber having an air inletand outlet discharging transversely into the secondary mixing chamber, a U-shapedby-pass having an air inlet opening communicating with the primar mixin chamber and a mixture outlet disc arging lnto said 'rimary mixing chamber, a fuel nozzle in t e by-pass, a rotatable adjusting plug mounted in one end of the by-pass, and a constant level tank closed to the atmosphere, said adjusting'plu having spaced lon 'tudinal passages provi ed with diametricall y oppositely disposed openings at points above the end of the by-pass m which it is mounted, both of said openings communicating with said primary mixing chamber, one of said passages extendln'g the bottom of the plug and the other of said passages commumcatm with the constant level tank at a point a ove the liquid surface therein.

GUIDO TACCONI.

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