US1484057A - Carburetor for internal-combustion engines - Google Patents

Description

' Feb. 19, 1924.;

c. BROWN I CARBURE'IOR FOR INTER AL COMBUSTION ENGINES FiledAug. 29. 1916 v 4 Shets-Sheet 1 MENTOQ Feb 19, 1924; iAMfiS? c. BROWN CARBURETOR FOR INTERNAL COMBUSTION ENGINES Fi led Aug. 29, 191s- 4 Sheets-Sheet 2 y Y wvENwQ,

- 1,484,057 c. BROWN 7 4 Sheets-Sheet 5 I 6 W W 5, M w r 0 O 40 0 W .6 5% 4 1 v 4 mg a 1. t h v k 0 1 5 Feb. 19, 1924;

CARBORETOR FOR INTERNAL COMBUSTION ENGINES Filed Aug. 29, 1916 Feb. 19, 1924; 1,484,057 0. BROWN CARBURETOR FOR INTERNAL COMBUSTION ENGINES Fil ed Aug. 29, 1916 4 Sheets-Sheet 4 ZMW v Patented Feb. 1 9, 1924.

" 1.484. 1 mam omen;

' CLEMENT BROWN, OF BIRMINGHAM, ZEENGLANIlZl.

GARIBURETOR FOR INTERNAL-COMBUSTION ENGINES.

Application filed August 29, 1916. Serial 110,117,506.

ply or float chamber.

' Carburetors with submerged jets are.

known in which the jets are in communication with the supply or float chamber and wholly subject to the influence of the suction created by the engine piston. The jet having an orifice of sufficient size to give the correct amount of fuel at low engine speeds feeds too much fuel at high engine speeds. To remedy this defect a second jet is pro vided which acts in supplementarycapacity to the first jet, equipped with a small orifice to limit the amount of fuel fed and having and air tube opening into the communication with the supply, whereby thejet is made independent of the suction created by the engine and permits fuel to flow slowly under gravity.

' It is therefore an object of the invention to provide a carburetor in which a single jet as is arranged, feeding into the main air passage of the carburetor and adapted to admit a variable quantity of fuel in accordance with the operating conditions of the engine.

' It is a further object of the invention to provide .with a jet with an atmospheric vent in the form of a conduit communicating, at the lower end, with a space above the jet and at the upper end with the atmosphere, the opening leading to the atmosphere being suitably restricted. Upon starting the suction set up by the engine will extract at v first the accumulated liquid fuel above the jet and afterwards continues to extractthe liquid fuel, but now from the jet which is 0 then submerged. At this time the full suction effect does not act on the jet, but only a part thereof, as the air inlet of the jet; partly neutralizes the suction effect of the engine.

It is a further object of the invention to provide a pilot jet with an air inlet having a restricted opening so as to partly neutralize the suction effect of the engine and there: by admit variable fuel quantities. To'the accomplishment of these and re.- lated ends, the preferred embodiments of the invention comprise the meansdescribed in the following specification, particularly pointed out in the claims forming a part thereof and illustrated in the accompanying' drawings which disclose, however, but several of the embodiments which are predicated on the principle of the invention.

In said drawings:

' Fig. 1 is a sectlonal plan view of one form of carburetor constructed in accordance with the invention; I

' Fig. 1 is a diagrammatic view to illustrate the action of the improved carburetor;

Fig. 2 is a rear sectional elevation of the carburetor shown in Fig. 1, the section being taken on the line 1-2 of Fig. 1;

Figs. 3, 4, and 5 show partial sections, similar to Fig. 2 of modified forms of the invention. a

Fig. 3 is a diagrammatic View based on the parts shown in Fig. 3;

Fig. 4 is a diagrammatic view based on the parts shown in Fig. 4;

Fig. 5 is a diagrammatieview based on the parts shown in Fig. -5, and

' Fig. 6 showscertain details referred to in connection with Fig. 5.

Referring to the drawings, and particularly to Figs. 1, 2 and 1, the improved carburetor has a straight air passage a and a main fuel inlet 6 which opens into the air passage 03 at the throat of the Venturi tube 0, 11. At a suitable distance from the inlet b a throttle member 6 is arrangedand adapted to close or substantially close the main air passage. The carburetor is equipped with a pilot jet f communicating with the passage a at a point in the vicinity of the throttle c so that when the latter is nearly closed an excessive draft is created in the vicinity of the vpilot jet. A main jet 9 is disposed below the normal level of liquid fuel in the float chamber h, (as indicated in 'the several 'figures bydash and dotted lines) constituting a so-called subiqmerged jet, and communicating with the liquid fuel level in the float chamber h, and the lower extremity of said air conduit is in communication with the space above the main jet 9 (Fig. 2).

A conduit 7' opens into the space above the main jet 9 and leads to a space below a pilot jet is arranged in the pilot fuel conduit Z, which leads to the pilot jet 7. The space above the pilot jet is has an atmospheric vent by a conduit m which, at the upper end, is suitably restricted by a nipple similar to the kind shown at the top of conduit 2' in Fig. 4, and which, at the lower end, terminates in the space above the pilot jet is and below the normal liquid level. The'capacity of the inlet of the air conduit m may be suitably adjusted by means of interchangeable nipples, such as shown at the top of the conduit 2' in Fig. 4. The arrangement of the parts is such that when the engine is stationary, fuel will stand above the main jet 9 and in the air conduit 2', in the conduit j, in the space above the pilot jet is and in the air conduit m the level being indicated by dash and dotted lines in Fig. 2.

The diagrammatic view shown inFig. 1 discloses in a simplified manner the arrangement and communication of the several jets and conduits and also discloses the level of a fuel.

which respectively communicate with the spaces above the main jet 9 and above the pilot jet 70. Upon starting of the engine, at first, the liquid fuel accumulated above the jets will be extracted, causing the latter to rush into the main air passage of the carburetor.

However, as soon as the fuel above the jets is withdrawn in the continued operation of the engine, further fuel is extracted from the jets but at a more moderate rate by reason of the presence of the air inlets z' and m, which communicate with the jets and'partly neutralize the suction efiect exercised by the engine.

When the throttle e is in nearly closed position there is greater suction in the main 421.11 passage a at the region of f than at the region of b, so that all the fuel passes through f. When, however, the throttle is fully open the liquid fuel is taken entirely from t e main jet 6 and no fuel passes through f as the suction is now greater at 6 than at f. The arrangement is such that so long as the negative pressure in the vicinity of the main fuel inlet 5 is suiiicient to extract liquid from the main jet, the pilot jet automatically remains out of action, but as soon as the throttle is so far closed that the suction in the vicinity of the main jet is insufficient to extract fuel therefrom, the fuel is taken entirely from the pilot jet.

In the modified embodiment of the present invention, as shown in Fig. 3 and diagrammatically indicated in Fig. 3, the parts a, o, b correspond to the parts 9, 2' and b of the first described modification with the exception that the conduit 1' is missing. The jet n which is advantageously used as a main jet is located in relation to the nozzle 6 and this jet has an air inlet 0 and is advantageously of the submerged type, as indicated in Fig. 3. The air inlet 0 is, at the upper extremity, equipped with a nipple 5 so as to restrict the inlet opening. A second conduit 10 independent of the first system then extends from the source of supply to a jet g, which communicates with an open top well i. From this open top well a" a conduit 11 extends to a jet k, w ich communicates with an air inlet chamber m, constructedsimilar to the air inlet 0. A conduit Z leads from the space above the jet is to the main air passage of the carburetor, where fuel is fed through the orifice f.

From the foregoing it is obvious that two means of feeding fuel are provided independently from one another; one comprising the parts a, 0, b and directly communicating with the supply, and the other embracing the elements g, k, m, Z and f and also connected to the supply. By virtue of the fact that the open top well '5' has not a restricted inlet opening, the jet 9 feeds fuel independent of the suction existing in the main air passage and cannot deliver more than a constant uantity of fuel at unit time determinedby t e size of orifice of jet g. But beyond this jet the air inlet m with the constricted inlet opening is provided and as a result of the presence of this air inlet m the orifice 7 does not. necessarily take all of the fuel admitbedto the valve 6 as the suction is partly neutralized by the restricted opening in the inlet m. Under certain conditions it may take all of this fuel, but under other conditions it takes a less quantity. The delivery system f is thus a nozzle which is variable per unit time, but which has a predetermined maximum delivery for it cannot take more than will flow from the jet 7- per unit time. When it has taken less than will flow per unit of time it may take a quantity which Varies per unit of time to any extent ranging between zero and the maximum defined for a gravity delivery at 9. During the period in which 7 is taking the available fuel, the flow at 9 would be constant per unit of time. But so long as the delivery at f is less than a maximum of which the nozzle 9 is capable, then neither the delivery at f or at g is constant per unit time because the excess delivery at 9 over that delivered at f accumulates in the unrestricted air inlet 11' and until it arrives therein to a level corresponding to that of the liquid in the supply. Having arrived at thls level if the delivery from 7 still continues to be less than that of which g is engine, but the suction efi'ect is moderated before it is accessible to the second jet. As-

' is it has, after issuing from the jet 9, to

series.

by the partial atmospheric vent provided for by the air inlet conduit 0.

In a further modified embodiment of the invention, as shown in Fig. 4 and diagrammatically indicated in Fig. 4, the main and pilot jets are entirely in series. Between the first jet g and the second jet k rovision is made whereby a certain hea of liquid has to accumulate above the first jet shown, a nipple p is interposed so that before the fuel is available for the pilot jet rise to ahead corresponding with the top of the nipple p. This head reduces the gravity flow from the float chamber under the head occurring in the float chamber. By interchanging the nipple p with one having a lower or higher top the rate of gravity flow from the jet g per unit time may be modi fied as requiredin connection with the pilot jet without affecting the delivery from the et 9 for the main nozzle 1). The jet 9' communicates with the space below'the nipple p and the nipple is disposed with its axis arranged vertically, whereby the liquid fuel rises in the nipple and flows by gravity from the'top thereof into a chamber which is in communication with the port j of the series passage communicating with the second of the jets which are in series. The first jet 9' of the series is utilized as a main jet, for which purpose it isplaced to feed to the fuel delivery orifice b and is provided with a conduit having a restricted air inlet 7?. The conduit communicates with the chamber above the interchangeable nipple p and is in communication with the main jet through the conduit in the nipple, the chamber below, the nipple and a conduit j between such chamber last mentioned and the space above the main or first jet of the The second or pilot jet k is the same as described in connection with Figs. 1 and 2. Y

The 1i uid fuel, when the throttle is open, flows thr ugh the jet and issues through the main nozzle 6 into the main air p assage of the carburetor. When, however, the throttle-is partially closed, the fuel must first rise until. itreaches the top edge of grammatically the ;.nipple p andv may then flow through the port j to the jet In, which is in communication with a restricted air inlet; It therefore follows that the action of this carburetor is identical with the action of the modification described in Figs. 1, 2 and 3 ensuring thereby a variable delivery of fuel per unit time both for the main jet and the .pilot jet by virtue of the provision of the air inlets having a restricted opening at the upper extremity.

In a still further modified embodiment of the invention, shownin Fig. 5 and diaindicated in Fig. 5, a further jet 9 is arranged in the series. This jet puts a maximum limitation upon the amount of fuel delivered per unit time by the carburetor. This jet may be disposed in the means of communication between the float chamber or other source of supply and a space below the first jet 9 An air inlet 1' is provided in connection with theinitial jet and as the air inlet is unrestricted the initial jet is entirely relieved from the suction effort of the engine acting, as stated before, and giving a constant maximum quantity of liquid per unit time. The discharge fromthe jet 9 may be modified by employing in place of the jets 9 other jets g or g (Fig. 6) of differing heights on the same principle as described in connection with nipple p in the modification shown in Fig. 4. The engine may use the full capacity of the jet Q, or'any less amount, in which case fuel accumulates in the air inlet '1' appertaining to the initial jet and or with t e choke, or in fact with any part' of the carburetor other than the initial jet to enable the carburetor to give more than the redetermined amount of fuel as defined by t e size of the initial jet.

The above mentioned firstjet g is of such size or capacity as to give the desired amount of fuel under the influence of the suction efi'ort of the engine and the liquid fuel for supplying the pilot jet is will then issue by gravity from said first jet. If the bore of the first jet should be such that more or less fuel issues than is required for the pilot jet, this may be corrected without altering'the capacity of the first jetby altering the head under which the fuel flows from the first jet. This may be obtained by The pilot v 19,. the first jet 9, g, or 9 determines the .70, is in use, so-that, as described in connection with the initial jet in Figs. 5 and 5,

maximum amount of fuel which is supplied to the pilot jetv k or k. The nozzle 6 or b is thus adapted to function as an air conduit when the pilot jets in or is are in use. It

' is therefore unnecessary to unduly restrict the pilot jet when the latter is level with or;v

above the level of the liquid fuel in the float chamber and a suitable space 70 is provided below the latter in which liquid fuel may accumulate to be used in starting. The pilot jet may be fed through a conduit 10 extending nearly to the bottom of this space, so that the contained fuel may be readily extracted.

While the drawings disclose preferred embodiments of the invention, I do not wish to be limited to the exact constructional features as shown but want to include all modifications constituting departures within the scope of theinventionas defined by the appended claims.

I claim:

1. In a carburetor for an internal combustion engine, a jet disposed below the normal liquid level in the supply, an air inlet inthe space below said second jet, a separateand independent air inlet communicating with the space above said second jet, and a conduit adapted to receive air and deliver to the main air passage of the carburetor in conjunction with said air the whole of the fuel received by the carburetor which is not delivered by said second jet.

2. In a carburetor, a well, means below the normal liquid level in the supply to supply fuel tosaid well, a restricted air inlet to the space in said well above. said fuel supply means; asecond well having a restricted air inlet at its upper portion, a conduit connecting the lower portions of said well, a nozzle leading from said conduit at a point intermediate its ends and-arranged to discharge into the carburetting chamber and a second conduit leading from the lower portion of the second well to the said chamber, said first named conduit being thereby adapted to receive air and to deliver to the carburetting chamber, in conjunction with such air, all of the fuel received by the carburetor which is not delivered by the first namedconduit through the second well.

In witness whereof I have hereunto set my hand.

CLEMENT BROWN.

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