US1851711A - Carburetor - Google Patents

Description

T. LINGA GARBURE March 29, 1932..

Filed Oct. 25, 1950 2 Sheets-Sheet 1 T. LINGA CARBURETOR March 29, 1932.

2 Sheets-Sheet 2 Filed Oct. 25, 1950 n E g Patented Mar. 29,- 1932 UNITED STATES TORBJ'ORN. LINGA, OF KOKOMO, INDIANA CARBURETOR Application filed October 23,.1930. Serial No. 490,577.

My present invention relates to betterments in carburetors, such as are commonly employed in association with internal-combustion engines.

It is well established'that such an engine will operate under ordinary running conditions smoothly and considerably more economically with a gaseous mixture substantially leaner than that required to produce maximum engine torque, for example, twenty per cent, to twenty-five per cent. leaner.

WVhen the accelerator is pressed fully down by the driver of the vehicle equipped with the engine, the greatest torque which the engine is capable of producing is desired, and economy is then of minor importance; but under usual running conditions with ordinary working load, when such maximum torque is not needed, a material saving in fuel consumption may be effected by changing thefuel-air ratio to produce a leaner mixture..

Hence the prime purpose of this invention is to provide a simple andefiicient means for automatically changing the gaseous mixture ratio of fuel to air in a carburetor from a leaner mixture at partly-open throttle to a richer mixture at fully-open or nearly complete open throttle, and vice versa, appliances of this general character being known as economizers. v

In the preferred form of the invention, this desirable result is accomplished by varying the pressure on the liquid fuel in the carburetor bowl or reservoir to secure a modified delivery therefrom, the specified change being governed or controlled bythe position of the throttle-valve.

In most carburetors, such fuel-reservoir is vented to the atmosphere so that the pressure acting on the fuel is that of the atmosphere, and, in other types or styles of carburetors, such fuel-reservoir is vented intothe intake of the carburetor or to the space between the carburetor and the air-cleaner, in'which instance, the pressure on the surface of the fuel in the reservoir is more or less subatmospheric,

My invention is adapted for satisfactory employment in either style of carburetor to obtain the required change in the mixture.

The pressure in a carburetor, above the venturi, or above the air-valve, if one is used, is less than the atmospheric pressure or that in the carburetor intake, and, in the new construction, I take advantage of this fact to modify the pressure in the fuel-reservoir for the indicated purpose by opening and clos ing a conduit between the two sources of different pressure.

Furthermore most types of carburetors are 7 equipped with a choke-valve to temporarily enrich the mixture for starting the engine and during its initial warming-up period, by

shutting off the air inflow more or less.

Such constructions are not entirely satis- I factory, because, when used, that is, when the wire or rod is actuated to close the chokevalve partly, the fuel mixture becomes in creasingly rich toward top speed, whereas, for proper operation, it ought to be richest at low speed. I

There is the additional objection of air resistance and loss of power when the chokevalve must be closedas much to effect a lowspeed mixture, as is usually the case. In my new construction, I have modified the choke mechanism so that by pulling the choke wire-or operating its rod or knOb a trated, and, for simplicity, like reference;

characters have been used throughout the several views to designate the same parts.

In these drawings Figure 1 is a vertical, longitudinal section through the carburetor on line 11 of F igure 2 V Figure 2 is a plan view of the carburetor with a portion broken away;

Figure 3 is a vertical, cross-section through. the throttle-valve portion of the carburetor on line 3-3 of Figure 1;

Figure 4 is a vertical, cross-section through the choke-valve portion of the carburetor on line 44 of Figure 1; and

Figure 5 is a fragmentary elevation of a part of the carburetor associated with the choke-valve.

By reference to the drawings, it will be noted that the carburetor-body 11 has an airinlet 12 equipped with a choke-valve 13, a mixing-chamber 14, a venturi 15, a throttlevalve 16, a fuel reservoir or bowl 17, an inlet pipe 18 therefor, and a float 19 in the reservoir actuating a valve 21 governing the inflow of fuel to maintain a constant level in the bowl, the fuel flowing from such reservoir to the air and fuel mixing appliance of the carburetor through a conduit or passage 22.

So far as described, the carburetor is of the usual construction, and the details of its structure need not be considered except to the extent hereinafter employed.

Along one side, the carburetor has a passage 23 connected through a conduit 24 to the top of the interior of the fuel bowl or reservoir 17 above the liquid therein, passage 23, through a metered orifice 25, communicating with the interior vof the air-inlet outwardly beyond the choke-valve 13.v

Throttle-valve 16 is mounted on or fixed to a rock-shaft 20 having near one end a bear- 26 in the side-wall of the carburetor and having -fixed on its other end a sleeve or bushing 27 which turns in a bearing 28 in the opposite wall of the carburetor.

Such sleeve or'bushing27 is slotted length wise at 29 for a portion of its length from its inner end, so that such slot is always in direct communication with the mixing-chamber 14 of the (carburetor.

' The specified slot, by the turning or rocking of the throttle-valve and its shaft and sleeve, is adapted to be brought into and out of communication with an upright passage 31 which intersects the bearing 28 in register with the slot, the lower end of passage 31 connecting with conduit 23 through a small metered orifice32.

(As is clearly shown in Figure 1, when the throttle-valve is closed, the upper part of the fuel-reservoirl? is indirect connection with the mixing-chamber 14 through the associated passages 24, 23, 32, 31, 29, and, when the throttle-valve is occupying'any position from about seven-eighthsopen to fully open, such connection isrclosed, because then slot 29 is out of communication with the conduit 31, it being clear that the slotted sleeve 2? acts as a rotary valve operated coincidentally wiith the ropen'ing and closing of the throttleva ve.

Turning now to the choke-valve 13, it will be seen that this is fixedly mounted on a rock shaft 33 having a bearing in the carburetor casting at 34, the adjacent, )rotruding end of the shaft being equipped with a coiled spring 35 tending to maintain the valve in fully-open position.

The other end of the shaft has a sleeve 36 oscillatory thereon, turning in a bearing 37 in the carburetor casting, and having a longitudinal slot 38 extending outwardly from its inner end, but terminating short of its outer end, whereby one end of the slot is always open to the interior of the carburetor airintake. I

The turning of such sleeve or bushing is adapted to bring its slot into and out of connection with the end of a passage 39 leading to duct 23 and much larger in cross-section than them-etered orifice 32.

An arm 41is fixed to the end of such sleeve or bushing 37 and is adapted to rock the latter when it is turned by a pull on the choke wire or rod 42 connected therewith, such arm having a pair of outstanding lugs or fingers 43, 44 spaced apart, between which is located an arm 45 narrower than the space between the lugs and riveted or otherwise fastened to the end of shaft Spring .35 tends to maintain the chokevalve 13 in full-open position, causing the lower edge of its arm 45 to rest against a stationary stop-pin 46 mounted and projecting outwardly from a bracket 48 held to the carburetor body by a screw 49.

The lower edge of .arm 41 also normally bears on such pin. v Another projecting pin 47 .on bracket 48 constitutes a stop for arms 41 and 45 to prevent the choke-valve from passing beyond its fully-closed position.

The new and improved structure operates practically as follows:

Under normal operating conditions, with the throttle-valve only part way open, for instance, one-half, the choke-valve is completely open, as show-nin Figure ,1, and the valve-sleeve .36 closes passage 39, but orifice 32 and passage 31 are open to the inside .of the carburetor, that is, to the mixing-ch amber 14 through slot for port 29..

Passage '23,, of course, is always open to the air-intake through port 25.

Inasmuch as the suctionor depression in chamber 14 is greater than that in the airinlet 12, a current of air will flow through orifice 25, passage 23, orifice 32, conduit 31 and slot 29 into the chamber 14, causing a certaindepression or degree of suction in the passage 23, which, of course, by reason of its connection 24, will be communicated to the interior of the fuel-reservoir above the liquid level therein, and this will, in a measure, determine the rate of fuel feed from the reservoirandtherichness of the resulting mixture.

If no connection 32, 31, 29 were provided, the pressure or depression in the fuel-reservoir would be approximately the same as that in the air-inlet 12, but by supplying such connection, the pressure in duct 23 is reduced, and such reduction is, of course, transmitted to the reservoir.

These various passages and orifices are so chosen as to size that an eflicient functioning of the carburetor results under the specified conditions, and an economy of operation accrues.

If a maximum engine torque is required and the throttle-valve is opened to some position of its last one-eighth opening movement, that is, if the throttle-valve is opened more than seven-eighths of its full opening, then sleeve 27 closes passage-31 and its metered orifice 32, thus reducing the suction, or increasing the'pressure, in passage 23 and in the fuel-reservoir, with a resultin greater feed of fuel and consequent enric ment of the mixture.

In such case, the pressure already in the reservoir would be about the same as that in the air-inlet.

Obviously, as soon as the throttle-valve iseven on ordinary days before the engine has had time to warm up adequately, when the operator would prefer to render the economizer for a time inoperative, wherebyto obtain a richer mixture even with the throttle only part-way open.

This he may accomplish by pulling on the wire or rod 42 enough to rock sleeve or bushing 36 to bring slot 38 into connection with passage 39, but without actuating the chokevalve 13. c

- Such manipulation of the part 42 turns arm 41 and the sleeve 36 sufficiently to establish the stated connection without moving arm or turning its choke-valve 13; but, of course, if a choke action is also desired, a further pull on the rod causes lug 44 to engage arm 45 and to close the valve 13 more or less. p

Under either one of these conditions, when slot 38 connects with passage 39, a second connection is formed between passage 23 and the air-inlet 12, and, since passage 39 is much larger in cross-section than that of orifice 32, the air flowing in through conduit 39 raises the pressure in the duct 23 and in the fuelreservoir, thus in a large measure neutraliz- 7 ing or overcoming the effect of the economizer and providing a rlcher mixture.

As soon as the choke wire or rod restores 5 3 the sleeve-valve 37, 38 to original position, the

economizer again functions to advantage as previously.

It should be borne in mind that the principles of this invention, as defined by the appended claim, are applicable to those constructions wherein the fuel-reservoir is vented either to the atmosphere or into the carburetor.

Those acquainted with this art will readily understand that the invention is not limited and restricted to the precise and exact details of structure shown and described, and that many more or less radical changes may be incorporated in the construction, without departure from the principles of the invention and without the loss or sacrifice of any of its material benefits or advantages.

I claim:

In a carburetor, the combination of a mixing-chamber, a throttle-valve, a fuel and air mixing appliance associated with said chamber, the carburetor having an air-inlet through which air is fed to said appliance, a choke-valve for said air-inlet, a fuel-reservoir, means to conduct fuel to said reservoir, means to convey fuel from said reservoir to said appliance, the carburetor having a passage connecting the interior of said reservoir with said air-inlet, a duct connecting said passage with said mixing-chamber, and ,a second duct connecting said passage with said air-inlet, a normally-open valve in said first duct closed during the latter portion of the opening movement of said throttle-valve, a normally-closed valve in, and adapted to open and close, said second duct, and means to first open saidsecond-duct valve and then close said choke-valve.

In witness whereof I have hereunto set my hand.

TORBJORN LINGA.

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