US2460528A - Carburetor - Google Patents

Description

0. OSWALD Feb. 1, 1949.

CARBURETOR 4 Sheets-Sheet 1 Filed Jan. 2'7. 1944 R m w m Feb. 1, 1949.

Filed Jan. 2'7, 1944 O. OSWALD CARBURETOR 4 Sheets-Sheet 2 1N VfN TOR o. OSWALD 2,460,528

CARBURETOR 4 Sheets-Sheet 3 Feb. 1, 1949.

Filed Jan. 27. 1944" Feb. 1, 1949. 0, osw 2,460,528

CARBURETOR Filed Jan. 2'7, 1944 4 Sheets-Sheet 4 Patented Feb. 1, 1949 Price CARBURETOR on: Oswald, Honolulu, Territory of Hawaii Application January 27, 1944, Serial No. 519,904

Claims. 1

My invention relates to carburetors, embodying an improved form resulting from experiments with and modifications of and additions to that illustrated by Figures 2-5 of my Patent No. 2,223,919, dated December 3, 1940, being also an evolution toward structural simplification and practical efiiciency of a species similar to that covered by my Reissue Patent No. 22,962, dated January 6, 1948.

In common with conventional carburetors, the general end sought by my invention is of course the production of a fuel mixture such. as to enable an internal combustion engine to function efficiently and economically. The ideal mixture to be delivered by the carburetor depends upon whether maximum economy of fuel, or maximum power output, or extreme fuel economy consistent with highest engine performance is required. My carburetor is adapted to achieve any one of said ideals within practical limits by the selective calibration of a single element, to-wit, that containing the fuel jets described herein.

It is well known to the art of carburetion that engine efllciency requires a fuel-mixture containing an accepted proportion of fuel to air supply, regardless of engine speed, andthat either leaning or enriching such proportion results in loss of power and performance, to say nothing of fuel economy, except that at maximum range of engine speed it has been found in the interests of maximum performance (albeit at sacrifice of fuel economy) to increase the fuel proportion at that stage.

Equally established in the art is the fact that the response of fuel such as gasoline to the influence of suction-induced air-flow past outlets discharging in a low-pressure area is in substantial ratio greater than increase in speed of such airflow. Consequently, when a carburetor is set to supply a correct mixture at any given engine speed it will yield a weaker mixture at lower speeds and a richer mixture at higher speeds, with the result in the first event of a loss of power and, in the second event, of a waste of fuelattended by a like loss of power when the richness is excessive. Objective D is in point here.

It is elementary in the art that the combustibility of liquid fuels is largely in ratio with their degree of vaporization at engine-intake ports; also, that gasoline, for example, may be vaporized under a high temperature without hazard of pre-ignition or detonation and will thereupon remain in such vapor form even while passing through a cool intake-manifold. In conventional carburetors the practice is to heat the air-fuel 2 mixture on its way through the carburetor or intake-manifold. However, it is equally elementary in the art that beyond a limited stage such heating of the mixture results in a lowering of engine efllciency because the resulting expansion of the air component reduces the weight or density of any given volume of mixture-charge. Objective E deals with such conditions.

Conceived and reduced to practice with the foregoing principles in mind, this invention operates as follows, broadly stated:

Automatically with increase in speed of airflow (a function of engine speed) fuel jets of predetermined and generally decreasing discharge area are placed in operative juxtaposition between a fuel-supply source and a discharge control element and then exposed to. the influence of throttle controlled engine suction induced primary air flow at atmospheric temperature, this air-flow being of a predetermined minimum proportion of the total air-flow under normal engine operation. The resulting air fuel mixture supply (which is too rich for proper combustion) is thereupon conducted so as to expose it to the full effect of the heat carried by the engine exhaust gases and then returned to mixing chamber of carburetor where at itspoint of discharge it commingles with automatically admeasured and admitted auxiliary air supply at atmospheric or other predetermined cool temperature, creating the total fuel mixture supply available to the engine at intake manifold. Also incorporated hereunder, to the ends of economy and efficiency, respectively, are the auxiliary features of a checkvalve in the idling fuel mixture supply line and an acceleration device, equally responsive to throttle valve control and cooperating with the other elements of this carburetor for the achievement of proper carburetion devoid of fuel wastage.

This caruburetor embraces in operative combination several novel constructions adapted to achieve, among others, the following specific objectlves:

A. (1) Rich initial fuel supply, to facilitate easy starting of engine;

(2) Avoidance of fuel. wastage incidental to untimely discharge of idling-fuel-mixture supply;

B. Automatic accomplishment of two distinct functions simultaneously by the engine suction induced air flow responsive movement of one element, to-wit,

(1) Actuation of an operatively connected fuel discharge control member;

(2) Admeasurement and admission control of a predetermined proportion of auxiliary to total air supply,

Both of the aforesaid operations being in ratio with speed of said air-flow through the carburetor;

C. Automatic control for the following purposes, dependent upon engine suction, of a. member operatively attached to the aforesaid actuating element,

(l) A predetermined length of forward movement of the aforesaid actuating element, free of compression-spring resistance;

(2) Cushioning of recoil of said actuating element coincident with sudden closure of throttle valve;

(3) Positive restoration of said actuating element to normal (at idling) positionfollowing the action in (2) aforesaid;

(4) Momentary braking and cooling effect upon the engine during the interval between (2) and (3) aforesaid:

D. Automatic selectivity of fuel-discharge area, to the end of fuel economy, and also to the end of limitation of engine speed to any predetermined amount inferior to maximum potential acc ding to speed of air-flow through the carburetor;

E. Maximum weight or density, consistent with maximum homogeneity and combustibility, of total fuel mixture charge to the engine;

F. Stabilization of fuel mixture supply responsive to acceleration movement of throttle valve;

G. Co-ordination of idling and acceleration fuel and air supply to the ends of eflficiency of response according to throttle valve position and of simplification of structure.

Thus my carburetor embodies other novel features of construction and arrangements and combinations of parts, as will be more fully hereinafter described and pointed out in the claims.

In the accompanying drawings:

Fig. 1 is a view in longitudinal section on the section line B-B of Fig. 3;

Fig. 2 is a view in transverse vertical section on the section line A--A of Fig. 3;

Fig. 3 is a plan view of the carburetor;

Each of the foregoing views discloses the carburetor in its relationship to intake and exhaust manifolds of engine;

Fig. 4 is an enlarged view in vertical section on the section line L-L of the unit referred to herein as accelerator housing a" which is shown in vertical section on Fig. 1 and in plan view on Fig. 8;

Fig. 5 is an enlarged seat-end view of the accelerator piston valve 80;

Fig. 6 is a view in horizontal section through the auxiliary air chamber 2|, viewed upward as delineated on bottom portion of air cylinder 2, Fig. 1;

Fig. '7 is a view in vertical section through the aforesaid auxiliary air chamber 2| on the section line M-M of Fig. 6;

Fig. 8 is a view in horizontal section through mixing chamber 5 on the section line C-C of Fig. 1;

Fig. 9 is a. view in horizontal section through said mixing chamber 5 on the section line DD of Fig. 1;

Fig. 10 is a left-end (entrance) view of choke tube I:

Fig. 11 is an end-view of air piston I0 and its operatively attached recoil plunger l8;

Fig. 12 is an enlarged view in vertical section throughfuel discharge control slide bar casing 34 on the section line K-K of Fig. 13;

Fig. 13 is an enlarged top plan view of the aforesaid casing 34, disclosing the multiple series of jets 35;

Fig. 14 is an enlarged top plan view of fuel discharge control slide bar 33, disclosing the several discharge outlets 38;

Fig. 15 is an enlarged view in vertical section through the said slide-bar 33 on section line JJ of Fig. 14;

Fig. 16 is an enlarged top plan view of operative assembly of the said casing 34, slide bar 33, and slide bar cover 31 hereinafter described. Also disclosed by this figure are the primary air-ports 36 of central body 3, the large outer circle of the figure indicating the countersunk portion 66 of the central body 3 adapted to fit the opposing projection on cover 4, this countersunk feature being shown also on Figs. 1 and 2, the last said feature being a preferred form of conventional construction. The said ports 36 are indicated on Fig. 1 merely by the vertical dotted lines in central body 3 extending between primary venturi 4i and mixing chamber entry port 50;

Fig. 17 is an enlarged view in vertical section on section line H-H of Fig. 16;

Fig. 18 is an enlarged view in longitudinal section through a conventional spring 16 which is shown confined between groove Tl of casing 34 and an opposing groove in lefthand projection of cover 3! (Fig. 1'7);

Fig. 19 is an enlarged plan view of said spring 16;

Fig. 20 is a plan view of contour of fuel bowl 3!! showing fuel float cup in place;

Fig. 21 is a view in longitudinal section of a check-valve adapted for insertion in the idling fuel supply tubing-line 48.

Throughout the drawings the reference character 2 indicates the air cylinder, this member having connected to its intake end a choke tube l containing a conventional choke valve 9 adapted for manual control. Discharge end of cylinder 2 is operatively fastened to vertical flanges of central body cover 4, central body 3, and mixing chamber 5, preferably countersunk on said members. Said cylinder is formed with auxiliar air slot 20 communicating with auxiliary air chamber 2| which discharges into mixing-chamber entry port 52. Air piston I, normally (at idling) positioned at intake end of and adapted for axial sliding movement in said cylinder 2, is operatively connected with fuel discharge control slide bar 33 by means of wristpin l5 and universal joint rod l6. Forward movement of said piston (except for the short initial space hereinafter described under objective CO) is opposed by compression coil spring I 1, said spring being so calibrated as to present yielding though increasing resistance to and in ratio with such movement.

Fig. 1 discloses that said air piston In is similar in comformation to the type illustrated by Fig. l of my Patent No. 2.223.919 and by my co-pending application Serial No. 296,967, having circumferentially spaced endports l l which communicate with central annular space I 00 which in turn communicates with central bore l3 by means of side ports l2.

Adjustablv attached to air admission end of air-p ston I0 is the rod and universal joint i9 which connects with recoil plunger l8, the operation of said plunger being as set forth hereinafter under objective A, said plunger having a close sliding fit in its cylinder 21 formed in choke tube I.

Mounted vertically on top of choke tube is conventional standpipe and tubing connector IOI with a central bore I02 which is in communication with blind and of plunger cylinder 21 by means of duct 94. conventionally connected to said standpipe I01 are tubing lines 99 and 91 (Figs. 1, 3, with central bore I02 of standpipe IOI by means of the duct 95. Tubing line 81 communicates with said bore 102 by means of duct I03 which is of diameter consistent with the size of tubin employed. Inserted in tubing line 99 is conventional check valve 99; and, similarly, check valve 98 is positioned in tubing line 91. The specific operation and function of each of said checkvalves is set forth under "objective A." hereinafter.

Choke tube 1 is disclosed by Fig. 10 as provided with air-entry ports 28 of an aggregate predetermined total air supply admission area equal to the maximum air requirements of this carburetor.

Central body cover ii is formed with primary air entry port 40 communicating through primary venturi 4| with central body air channels 35 (Figs. 2 and 16). Venturi 8! is so calibrated and positioned that low-pressure area during engine operation is at the fuel discharge outlets 33 of slide bar 33. Said cover d is perforated for conventional connection with fuel supply line 52 (Fig. 3) the discharge from which is controlled by a conventional valve (not shown) mounted underneath said connection and in operative contact with float 29 (Fig. 1). Said cover 4 is also adapted to receive fuel 'plug 53 the purpose and functioning of which is disclosed under objectives F and G hereinafter.

Central body 3 is cast or otherwise made to conform with the arrangement of chambers and other features, as follows: Reference numeral 65 indicates the portion preferably countersunk (Figs. 2 and 16) to receive the opposing projection of the cover 4. The air channels 36 are adapted to pass therethrough a predetermined proportion of primary to total air fuel mixture supply. A fuel bowl 39 contains a' conventional float 29, controlling a fuel inlet valve as aforesaid, confined in the cup I01 (Fig. 20) which is open at top of bowl, a perforation being provided in said cup below the predetermined fuel level in said bowl to admit fuel supply to overflow into the remaining portion of the bowl containing the inlet portion of fuel plug 43 and the inlet to horizontal fuel duct 3|, this cup being indicated on Fig. 1 merely by dotted vertical lines outside of fuel bowl outline. By means of said duct 3i fuel is brought to the feeder ducts 32 the multiple series of which are at all times in operative juxtaposition with the similarly spaced series of jets in casing 34. The fuel discharge control assembly, comprising casing 34 with slide bar cover 31 and laterally confined slide bar 33 (more fully described hereinafter) is mounted and removably secured in position by conventional means centrally on longitudinal axis of the body 3 and is generally similar to theform disclosed under my Reissue Patent No. 22,962.

Reference numeral 5 designates the mixing chamber which is formed with an upper flange removably fastened to central-body 3, having a lower flange adapted for operative connection with an intake'manifold preferably fashioned as illustrated by the drawings (Figs. 1 and 2) and Tubing line 99 communicates air supply channels 34 (Fig. 9) and central airpassage 53 (Figs. 1, 2) with auxiliary air' discharge channels 65 (Figs. 2, 8) which lead into,

secondary venturi 56 (Figs. 1, 2). 'Also formed in upper end of chamber 5 is primary fuel mixture supply entry port .which is controlled by a conventional throttle valve 58 for the purpose of metering and admitting the raw primary air fuel mixture supply produced by engine suction induced air flow past the fuel discharge outlets 3B of slide bar 33, through the port 5i intopipe 54. This pipe 54 conducts the said primary mixture-supply through its connections 10 at exhaust manifold 1 into heating tube H (Fig. 2), the resultant heated primary mixturesupply then discharging through connection 12 and pipe 51 to enter mixing chamber -5 at port 55 whence it continues downward to meet auxiliary air supply at the secondary venturi 56 I to form the total air fuel mixture supply which enters port B0 of intake manifold 5.

The said exhaust manifold 1, while formed with the aforesaid special features, is not claimed, being old in the art, and is adapted for conventional connections to engine exhaust discharge ports, Figs. 1 and 3 illustrating said manifold with ends broken due to space limitations.

Said intake manifold 6, having conventiona connections for engine intake ports, although here shown formed in one piece is of the type illustrated by Figs. 1 and 5 of drawings accompanying my Reissue Patent No. 22,962, being adapted for inclusion of an impeller or supercharger fan, such inclusion being facilitated by the removably fastened bottom-cover I05. ihe

reference character BI is applied to the discharge ports of this manifold 6.

Although Figs. 1 and 8 illustrate a direct physical connection of my accelerator-housing 8 with mixing-chamber 5 at the entry duct ill, I do not confine myself to that specific hookup For instance, the said accelerator unit might be mounted on top of fuel plug 43 (somewhat as' Y illustrated on Fig. 1 of my Reissue Patent No.

22,962) by means of a short vertical pi-pe connection so that fuel-duct 49 of plug 43 will empty of the mixing chamber port 55 near its discharge end at secondary venturi 56. By reason of such location the said duct 9i is subject to and transmits through said tubing line 92 the influence of whatever degree of engine suction is operative at 'any position of throttle valve, all and more as detailed in disclosure under the caption of .objective F. 1

Connections to mixing chamber!) of the tubing lines 96 and 91 leading from top of choke tube I (hereinbefore referred to as on Fig. 1) are shown by Fig. 8, the lower end of tubing line 96 alone being in view on Fig. 2. The said lower end of tubing line 95 communicates with the rear auxiliary air channel 65 as shown in Figs. 2 and 8; and since this channel is not intersected by section line BB, on which Fig. 1 is drawn, it

is considered impracticable to show this feature on said Fig. 1. By means of said connections with one of auxiliary air channels 65 the influence of engine suction is effective upon the check valves 98 and 99, the resultant reaction of air piston plunger i8 being as set forth under "objective C. Also operatively connected to mixing chamber so as to be subject to engine suction under circumstances disclosed hereunder is the idling fuel mixture supply tubing line 48 which by means of idling discharge duct 59 communicates between primary fuel mixture discharge port 5| (Fig. 1) and fuel storage ducts 49, 48, 41 and cross-bore 45 of the fuel plug 43. Inserted in said tubing line 48 is a cylinder 62, illustrated in elevation on Fig. 1 and in enlarged cross-section by Fig. 21, containing a spring-balanced ball-valve 83, the function and operation of which are detailed under objective B (2) Vertical cross-sectional view. (Fig. 1) of fuelplug 43 discloses that it draws a fuel supply from the bowl 38 by means of the jet 44 which is callbrated to admit only sufficient fuel for idling purposes, this supply passing through cross-bore 45 and (during idling of engine) is, together with air supply admitted through air duct 48, mixed in and drawn upward through duct 41, along tubing line 48 and into mixing chamber 5 at the conventional position shown between throttle valve and intake manifold. Control of the idling air supplyis had by means of a conventional screw 39 (Fig, 3). Other features of said plug 43 and its several operative connections and functions are detailed under the objectives F" and G."

As hereinbefore briefly adverted to, the fuel discharge control assembly comprises the several elements illustrated in their substantially relative proportions by Figs. 1 and 2 and in enlarged detail by Figs. 12 to 19 inclusive, formed, adapted and coacting as follows:

Casing 34, formed in one piece with guide 19, is provided with manually adjustable guides 26, these guides serving generally to confine the slide bar 33 adapted for longitudinal sliding movement there-between. Reference character I84 points to chamfers on said adjustable guides, the chamfers having of course the purpose of minimizing the friction incidental to such sliding movement. Provided in the casing 34 are longitudinal plural series of vertical jet apertures 35 (which may be drilled in the casing 34 as illustrated or removably inserted as individual jets therein) preferably out of transverse alinement with each other and generally decreasing in discharge area from left to right in the position shown in the drawings, with the last several jets having predetermined increased discharge areas to provide for added power desired at extreme engine speed. These jets are individually of discharge area predetermined as adapted for purposes of highest fuel economy consistent with the engine performance at speed of air flow through the carburetor at which any specific jet or portions of several jets discharge under the control of slide bar 33 as hereinafter described under objective D. Reference character 15 designates chamfer on side of slide bar 33 in contact with fixed guide 19.

Reference character I86 designates the guide portion of the slide bar cover 31 which is likewise chamfered (Figs. 16, 17). This cover 31 is formed with an inwardly projecting lip on one side (Fig. 1'7) which engages groove 18 of casing 34, and upon its downward projection on the other side the said cover is provided with a groove opposing a similar groove 11 of casing 34, and confined between said grooves is a conventional corrugated spring 16. In the position illustrated by Fig, 17 the spring 16 is under compression which has two simultaneous effects, to-wit, movably confining said lip in groove 18 and holding said cover I86 against one edge of slide bar 33, the end results being that (a) lateral "lost motion (due to eventual wear of sliding surfaces) is obviated, and (b) operative contact is maintained between the horizontal fuel discharge control under-surface of slide bar 33 and jet discharge surface of casing 34. In the event of failure of the spring 18, the said fixed guide 19 and the adjustable guides 26 would perform their function of generally and operatively confining slide bar 33.

In its longitudinal movement, slide bar 33 by means of its several perforations 38 is adapted to selectively control fuel discharge from the outlets of the jets 35 of casing 34, as more fully set forth hereinafter under the caption objective D.

Obviously, it would be within the spirit and scope of this invention to substitute for the aforesaid fuel discharge control assembly a simple slide bar and easing resembling the unit disclosed under my Patent No. 2,223,919 wherein the slide bar is contained in and guided by a casing having fixed guides, the multiple series of jets being then carried in the slide bar. I

The unit hereinabove designated accelerator housing 8" is'shown in vertical section on Fig. 1 and in plan view by Fig. 8. Adapted to move axially in this accelerator housing is accelerator piston valve 88, an enlarged front view of which is given by Fig. 5, revealing the peripheral disstribution of the scallops 84 through which air or other gas may be admitted when valve 88 opens under the conditions recited under objective F. Said valve 88 is held to its seat, closing ports 85, by normal engine suction transmitted through ports 9! and 98 and chamber 81 and exerted at said ports 85 and through duct 89, compressing spring 88 in chamber 14. Adjustably attached to valve 88 is recoil plunger 86, by means of rod and universal joint 13. However, it is obvious that valve 88 and plunger 88 could be formed in one piece for their respective purposes. Pierced in mixing chamber end of chamber 14 is an air bleeder duct 89 of predetermined small diameter. Valve 88 is formed with central bore 8| communicating by means of side ports 82 with annular space 83 into which open the scallops 84, these scallops being of predetermined aggregate area less than bore of discharge duct 98. Fuel or a fuel mixture supply may enter housing 8 opposite head end of valve 88 by means of connection with tubing line 92 (Fig. 8) communicating with fuel plug 43 (Fig. 1). The purpose and manner of operation of the aforesaid accelerator housing and assembly is disclosed under the caption of "objective F." 1

Toward the several objectives hereinbefore listed, this carburetor is adapted to function as follows:

A. (1) At the moment of, starting the engine all three of fuel plug ducts 46', 41 and 49 as well as crossbore 45 are filled with fuel to the level controlled by float 29, this fuel having entered said plug through jet 44 which is calibrated for idling fuel supply purposes. Availability of such initial fuel supply ensures the rich charge required at this stage of operation, the total of such initial supply being predetermined and the respective areas of said ducts being calibrated accordingly. ,After such initial supply has been exhausted the regular idling fuel mixture supply is formed by the air from'duct 46 passing over discharge tip of jet 4G and continuing as an air-fuel mixture through cross-bore 45 and duct s1 into tubing line 48 whence it finally discharges into mixing chamber 5 through the duct 59 conventionally situated on the intake manifold side of throttle valve 58. Hence it is correct to say that both fuel and an air-fuel-mixture supply are induced by suction through the idling tubing line 58, successively, or that fuel or an air-fuel-mixture supply is so induced, or that the fuel charge so induced may consist of either straight fuel or an air-fuel-mixture supply, depending upon the contemporaneous operating condition.

(2) It is well known to the art that during normal engine operation the highest degree of partial vacuum obtaining in intake manifold occurs under no-load conditions best exemplified at idling speed with the engine vehicle at a standstill. If now the throttle is gradually opened wider the increased engine speed will maintain the degree of vacuum substantially as at idling. However, if while the engine is operating at a speed appreciably above idling the throttle valve is suddently closed the immediately noticeable result will be a sudden jump of such vacuum to adegree nearest approaching the perfect vacuum, which will return to normal with the "resumption of predetermined normal idling speed. The same heightening of partial engine vacuum occurs at any stage of operation with throttle valve closed when the engine of the vehicle is decelerating at greater than idling speed on the level or descending a grade.

Whereas the conventional idling fuel mixture supply elements are theoretically adapted to cease functioning at a throttle valve position resulting in a speed of approximately miles per hour under no-load conditions, because of the absence of any idling fuel supply shut-01f device the said elements necessarily continue to make available to the engine the regular idling fuel mixture supply under the aforesaid conditions of deceleration or acceleration under closed throttle valve. The volume of such fuel expenditure per unit of time will be in ratio with engine speed and, clearly, constitutes a sheer waste of fuel as well as a factor recognized in the art as disadvantageous to proper engine operation and maintenance.

The functioning of my air piston 10 .(see object B, lines 24-32, column 10) tends to prevent idling fuel discharge during deceleration, as follows: When at any speed appreciably above idling the throttle valve is abruptly closed, the

aperture is at least partially open due to the forward position of piston Ill, and consequently a supply of auxiliary air continues through the carburetor until the deceleration approximates idling speed, and this circumstance reduces engine vacuum to a degree insuiiicient to induce idling fuel discharge during such period. However, for purposes of avoiding the said fuel wastage during deceleration with throttle valve in closed position-as when engine vehicle is descending a grade in gear under closed throttle- I have provided in the idling fuel mixture supply line 48, as a component of this carburetor, a cylinder 62 containing a check-valve (Fig. 21).

10 The ball 63 is preferably balanced between corripression-spring 61 and recoil-spring I09 in said cylinder. The calibration of spring 61 is such that it resists predetermined degree of engine vacuum, the ball 63 remains in the neutral or open position illustrated by Fig. 21, so that normally the fuel mixture supply passes through the cylinder and on to the mixing chamber as hereinbefore related. When (under the aforesaid conditions of deceleration) the degree of engine vacuum exceeds the said normal, the tension of springs 61 is overcome and the ball 63 is impelled to seat at and close the bore. Hi8, said closure persisting until the engine vacuum returns to its said normal degree.

B. (1) Air piston I0 is so fashioned and adapted that, upon opening of throttle valve 53 beyond the idling position illustrated (Fig. 1) the engine suction induced air-flow through the multiple piston-ports H and i2 and central bore 93 with the attendant pressure upon solid portions thereof impels piston movement to the right (Fig. v(1), against the tension of compression spring ll, in ratio progressively with increase in speed of air flow due to increase of throttle opening under no-load conditions. Under circumstances of increasing engine load and static throttle valve the relative piston position is a function solely of air flow speed. Naturally, reversed throttle movement (toward idling position) is accompanied by retrogressive piston movement, under the urging of said spring ll together with the co-operation of the elements hereinbelow described under the caption of objective C."

The aforesaid movement of piston it is imparted, by means of wristpin l5 and rod it, to the fuel discharge control slide bar 33 which by means of outlets 38 selectively registers with and ggntrols discharge from fuel jets in casing (2) Piston it is also so fashioned and adapted that its said movement places annular space lfill thereof into operative juxtaposition with auxiliary air intake slot 20 of cylinder 2 and thereby admeasures and admits the air chamber 2| an auxiliary air supply of predetermined major proportion to the primary fuel mixture supply controlled by the throttle valve 58, this auxiliary air supply thereupon passing through mixing chamber ports and channels 52, 6d, 53 and 65, respectively,'finally commingling with the heated primary air fuel mixture supply of secondary venturi 56 for discharge into intake manifold 8 at its entry port 60. The said heated primary air fuel mixture supply originates as described hereinbelow under the caption of "objective E.

Adjustment of the effective air admission area of said slot 20 is provided for by means of the horizontally movable valve 22 rigidly fastened to the shaft 23 which is pivoted upon the raised seat surrounding slot 20; this shaft may be secured in the desired position by such well known means as tubing locknut 25. The otherwise free end of valve 22 is flexibly kept in contact with said seat by means of fiat spring 24 or other conventional element permitting horizontal displacement of the valve. (Fig; l, 6, 7.)

C. For this objective the means employed are tubing lines and 91 incorporating check valves 99 and 98, respectively, of conventional pattern, said lines communicating between the blind end of cylinder-space Zl (of choke tube I) and mixing chamber 5 (Figs. 1, 3, 8, 10). The said elements are so placed and adapted that at idling of engine the check valve 99 opens and check valve 98 closes to engine suction; then through the open valve 99 the engine suction is transmitted by means of air bleed ducts 95 and 94 respectively to the said blind end of cylinder-space 21, causing a partial vacuum therein and resulting then in the relative positions of the elements as illustrated by Fig. 1.

(1) Initial opening of throttle valve 58 for an engine speed beyond idling causes closure of check valve 99 and simultaneously permits opening of check valve 98, resulting in a pressure approaching atmospheric in said blind end of space 21. Air piston compression spring I1 is so positioned and calibrated that it ofiers only slight resistance to a predetermined short forward sliding movement of the piston l coincident with such throttle opening movement, such effect upon the piston being induced as disclosed under the foregoing "B (1). The purpose of this arrangement is to avoid the otherwise compartively sluggish response of piston In due to the low speed of suction induced air flow contemporaneous with a small throttle opening, to the end of initiating the admission of auxiliary air supply concurrent with admission of a primary air supply by said throttle opening, the said auxiliary air supply passing through the carburetor in the manner recited under the foregoing "objective B (2)."

(2) When at any given engine speed the throttle valve is suddenly closed, the simulta neous cessation of air flow through the carburetor together with tension of spring I! would normally cause piston ID to slap back against discharge end of choke tube l in the absence of some form of recoil or shock absorbing element; for such purpose I have provided the plunger I9 in its cylinder 21. Such closure of the throttle valve, affecting immediately as it does the degree of engine vacuum, opens check valve 99 and closes check valve 98 to engine suction, the result being that the retrogressive movement of piston imparted to its plunger i8 encounters the compressive resistance of the air confined in whatever space exists at the time between head end of said plunger and the blind end of cylinder 21 unrelieved except by the slender exit afl'orded by air bleed duct 95, thereby achieving a gradually diminishing cushioning effect at recoil.

(3) Due to the opening of check valve 99 to engine suction (at idling) and the closing of check valve 98, as aforesaid, a partial vacuum is created in blind end of cylinder 21 which causes a return of plunger l8 to its normal (at idling) position after the tension of spring I! has ceased at the predetermined position already disclosed.

(4) At any opening of throttle valve 58 for an engine speed faster than idling, a predetermined proportion of auxiliary to primary air supply is flowing through slot 20 and into the carburetor mixing chamber 5. Sudden restoration of throttle valve to idling position, with the results mentioned in the foregoing C' (2), allows a gradually diminishing flow of such auxiliary air supply to continue through the carburetor during the appreciable interval of time until the elements mentioned in objectives 0 (2)" and C (3). have functioned and piston III is again normally positioned. Such flow of air at atmospheric temperature, devoid of throttle valve control, continues on to the engine intake manifold and cylinders attended naturally by a 12 partial cooling and braking effect thereon, as well as preventing the unnecessary discharge of idling fuel supply by diminishing the degree of engine vacuum required for normal idling purposes as hereinbefore referred to under object A (2).

D. Sliding movement of the bar 33, under the conditions described in the foregoing paragraph "B (1) places one full discharge outlet 39 thereof in operative juxtaposition with one jet 35 of casing 35, or a portion of each of two outlets 39 in similar relationship with two jets 35, so that at any position of the said bar '33 -the equivalent of one full jet area is in proper fuel discharge alinement.

Inasmuch as (1) piston I9 is responsive to speed of air flow therethrough and its resulting movement is by the aforesaid operative connections imparted to slide bar 33, and (2) the said slide bar 33 positively and selectively controls fuel discharge from jets 35', and (3) said jets 35 are of generally decreasing discharge area predetermined for the purpose, it follows (4) that maintenance of the desired proportions of air and fuel is a function of the air flow speed through the carburetor. By leaving blank a predetermined number of jets 35 at righthand end of the series shown in Fig. l the foregoing arrangement becomes also an automatic speed.- governor.

Preferably, as appears from Figs. 12 and 17, the discharge portion of each jet 35 in casing 39 is enlarged to a uniform area which is substantially equal to the discharge area of each of the slide bar outlets 39.

Obviously, instead of the fixed jet apertures illustrated by the drawings, the casing 34 may be provided with individual jets screwed or otherwise inserted so as to be conveniently changed.

E. The proportion of primary air fuel mixture to auxiliary air supply for any air flow speed is of a predetermined minimum consistent with effective throttle valve control. The primary air fuel mixture supply, under the control of throttle valve 59, in passing through the heating tube H is subjected to the full heat of the engine exhaust gases in the exhaust manifold, and consequently when admitted into the mixing chamber 5 at port 55 such mixture is in a highly vaporized state although too rich in proportion of fuel to air. The auxiliary air supply, at atmospheric or other predetermined cool temperature admitted to mixing chamber 5 as hereinbefore disclosed, meets and commingles with the heated primary mixture at the secondary venturi 59. This member 56 is so calibrated and positioned as to exert a Venturi-like effect upon the incoming independent streams of (a) heated primary air fuel mixture supply and (b) cool auxiliary air supply, the result being a thorough homogenizing of the said streams to form a total air fuel mixture charge of maximum weight and power consistent with a high degree of combustibility.

F. This objective is concerned with the carburetion problem of stabilizing a continuous supply of fuel to the engine during the appreciable lag which attends any sudden opening of throttle valve after the engine is in operation and particularly when under load. Conventionally, when quick acceleration is desired, the throttle valve is opened wider, the immediate effect being apparent in a momentary loss of power due to the consequent decreased suction upon the jets. In conventional carburetors this 13 condition is met by various devices, frequently involving physical connection with the throttle lever. Seeking to improve upon said types and upon my own similar device illustrated under Reissue Patent No. 22,962, I have embodied .as an integral part of this combination carburetor the accelerator unit hereinbefore described (Figs. 1, 4, 5, 8). By means of the automatic response and the adaptation of said accelerator the required rich excess charge is delivered in the carburetor near its discharge end at intake manifold with the first resumption of partial engine vacuum following the aforesaid sudden opening of throttle valve; also, for an appreciable interval of time an air-fuel-mixture discharge follows and thereby supports and stabilizes the recovering pickup of the regular air-fuel mixture induction from the main jets and air supply. Further, my accelerator avoids a fault inherent in some forms of said conventional devices, towit, the unwanted and unintentional injection of excess fuel caused by involuntary movements or pressure by the vehicle-operator's foot upon the throttle pedal.

My said accelerator unit is adapted and operates a followsz In Fig. 1 the piston valve 80 is shown in normal position, seated, the double lines at seat indicating a scaling gasket of conventional material perforated for the scallops 8% or for the ports 85 according to whether the gasket is placed on head end of piston or on housing seat at said end.

Piston 88 is held to its seat by suction, during normal engine operation, applied in chamber 81 through the ports 85 and in chamber it through duct 89. Upon sudden opening of throttle valve 58 the attendant intereference with normal engine suction affects both the piston to and its attached plunger 86, more or less nullifying the partial vacuum normally existent in chambers 14 and 81 and thereby releasing restraint upon spring 88 which by extension then unseats said piston. The quickly following recovery of said normal engine suction transmitted through intake manifold E at the port so is first experienced in the carburetor at the duct 9i and thereby in the accelerator housing in chambers 1E and 8'! and in the seat end of piston chamber, causing a spray of fuel or a fuel-mixture from tubing line 92 (Fig. 8) to enter said piston chamber and there to commingle with the small amount of air passed through said piston valve 80 by means of central bore 8|, side ports 82, annular space 83, and scallops 84, this mixture being then drawn through ports 85 and the forward end of accelerator housing and port 90 into mixing chamber through-duct 9|. Such discharge into the mixing chamber continues for the comparatively brief interval predetermined by the small effective area of air bleeder duct 89, being the period of time required by the restored normal suction to again create a partial vacuum in chambers 14 and 81 which acts to reseat the piston. Fuel delivered by said tubing line 92 is drawn'from the main supply in fuel bowl 30 (Fig. 1) by means of duct '49 of the plug 43, air being supplied through duct 46 of said plug to form an airfuel mixture richer than normally required by the engine at any steady speed. An air vent 93, of very small bore, is provided horizontally near the top of said duct 49, for the purpose of avoiding v back-pressure in duct 49 at closed position of piston valve 80 and to offset any minor air. leakage between said piston and its seat at times when the piston should be firmly seated.

Another stage of engine operation involving sluggish response of fuel to air flow, similar to that mentioned above, occurs when the engine is under heavy load ascending a grade in high gear. Under such circumstances the throttle valve must necessarily be opened wider to maintain a given speed, resulting in a lower degree of engine vacuum compared with that existing at the same speed under no-load conditions. This lower degree of vacuum in turn allows an appreciable opening of accelerator piston 80 whereupon an acceleration fuel. mixture supply enters the mixing chamber to augment the regular fuel mixture supply during such heavy-load period. At the commencement of this heavy-load stage the initial acceleration fuel mixture supply consists of the fuel accumulated in the ducts 69, d5, 46 and ti mixed with air but excessively rich, and for the remainder of said open-valve period such mixture is of the same proportions as the regularly admitted idling fuel mixture supply.

G. Fuel-plug '33, together with its tubing lines 48 (idling) and 92 (acceleration) operatively connecting it with mixing chamber 5, is an integral part of my combination carburetor hereunder in that it co-operates, under control of throttle valve 58, with the other elements of said combination to produce a common result, to-wit, the carburetion of fuel for an internal combustion engine, as follows:

(1) When the engine to which this carburetor is attached is not in operation fuel occupies the ducts 4t, 4?, 59 and cross-bore $5 to the level controlled by the float 29 and its conventional needle valve hereinbefore mentioned, the said supply of fuel having been admitted to the ducts through the jet dd set in the bottom of said plug 53. At starting of engine, with throttle valve 58 substantially closed, all of this fuel supply in said ducts is instantly available for engine idling purposes;

(2) While the engine is operating under light or no-load conditions at speeds above 15'miles per hour (as with any conventional carburetor), engine suction upon tubing line 68 has ceased, and the said ducts refill with fuel.

(3) Under the conditions described in the foregoing section F, the initial acceleration fuel supply instantly available comprises, as in the foregoing paragraph, that contained in'ducts d6, d1,

Q8 and cross-bore 45, together with air drawn through duct 46. When the need or stimulus for an acceleration fuel mixture supply has ceased with the engine operating normally, the said ducts again refill with fuel available for the purposes aforesaid.

Under each of the foregoing conditions recited in paragraphs 1, 2 and 3, the one jet 44, calibrated for idling purposes, admits all the fuel required, and the one duct 46 supplies the air, and upon the manipulation or position of throttle valve 58 depends the said functioning for either idling or acceleration purposes.

Obviously, this carburetor contains within itself the potentiallty of a maximum-speed governor without the addition of any other element or mechanism, as follows:

By closing any predetermined number of jets in end of easing representing extreme-speed range of engine, any desired maximum-speed limitation may be achieved; and such limitation may not be tampered with except by disassembling the entire' carburetor.

While I have illustrated and described what I believe to be preferred embodiments of my invention an integers thereof, it is apparent that various changes might be made in the general form and arrangements of parts without departing from the spirit and scope of the invention, hence I do not limit myself to the specific details set forth but consider myself at liberty to make such alterations as fairly fall within t spirit and scope of the appended claims.

.I claim:

1. In combination in a carburetor for an internal engine having an air inlet and an outlet adapted to be connected to the manifold of an engine, a mixing chamber for mixing a primary air-fuel mixture with additional air, a primary air passage between said inlet and said mixing chamber, fuel supply means opening into said primary passage, a throttle in said primary air passage between said fuel supply means and said mixing chamber, an auxiliary air passage adapted to by-pass said fuel supply means and said throttle in communication with said primary air passage through said mixing chamber, and piston means responsive to engine-suction induced total air flow for forming and controlling an airfuel mixture of predetermined proportions, said latter means including fuel metering means adapted for progressively uncovering fuel orifices of varying discharge area and means for varying the amount of air diverted into said auxiliary air passage.

' 2. In combination in a carburetor for an internal combustion engine having an air inlet through which the total air must pass and an outlet adapted to be connected to the manifold of an engine, a. primary air passage between said inlet and said outlet, fuel supply means opening into said primary passage, a throttle in said primary air passage for controlling the flow of an air-fuel mixture therethrough, means operatively associated with said primary air passage for heating the air-fuel mixture flowing therethrough, an auxiliary air passage adapted to bypass said fuel supply means and said throttle and in communication with said primary air passage at a point between said heating means and said outlet, and piston means responsive to the enginesuction induced total air flow through said air inlet for controlling the formation of an air-fuel mixture of predetermined proportions in said primary air passage, and for diverting a portion of the air in said inlet into said auxiliary air passage for adding auxiliary air to said heated airfuel mixture in said primary air passage.

3. In combination in a carburetor for an internal combustion engine having an air inlet and an outlet adapted to be connected to the manifold of an engine, a mixing chamber for mixing primary air-fuel mixture with additional air, a primary air passage between said inlet and said mixing chamber, fuel supply means communicating with said primary air passage, a throttle in said primary air passage between said fuel supply means and said mixing chamber, exhaust manifold heating means operatively associated with said primary air passage for heating the resulting primary air-fuel mixture, an auxiliary air passage between said inlet and said mixing chamber adapted to by-pass said fuel supply means, said throttle and said heating means, and means responsive to the engine-suction induced total air flow for simultaneously varying the discharge of fuel into said primary air passage and for controlling the communication between said inlet and said auxiliary air passage for adding auxillaw air to said heated air-fuel mixture in said primary passage.

4. In combination a carburetor for an internal combustion engine having an air inlet and.

outlet adapted to be connected to the manifold engine, a primary air passage between said inlet and said outlet, fuel supply means in said primary air passage comprising a plurality of fuel metering ducts of predetermined varying sizes, and valve member having openings adapted to be selectively aligned with said ducts in a predetermined order, a throttle in said primary air passage for controlling the flow of an air-fuel mixture therethrough, a mixing chamber, exhaust manifold heating means operatively associated with said primary air passage for heating the airfuel mixture flowing therethrough, an auxiliary air passage adapted to by-pass said fuel supply means and said throttle and in communication with said primary air passage through said mixing chamber, engine suction responsive means responsive to the speed of the air flow through said air intake adapted for dividing the total air supply required in any stage of engine operations above idling speed and below the maximum potential engine speed into predetermined proportions of primary and auxiliary air supplies, said engine suction responsive means also operatively associated with said valve member for selectively uncovering said fuel metering ducts in such order as to provide fuel outlets of a total area varying at a rate generally in inverse ratio with respect to the speel of air flow through said inlet and thereby forming an air-fuel mixture under the control of said throttle valve which is mixed with a predetermined amount of air from said auxiliary air passage, and idling fuel supply means having a discharge port in said primary air passage on the engine intake manifold side of said throttle.

5. In combinationin a carburetor for an internal combustion engine, having an air inlet and outlet adapted to be connected to the manifold engine, a primary air passage between said inlet and said outlet, primary fuel supply means in said primary air passage comprising a plurality of fuel metering ducts of predetermined varying sizes and a valve member having openings adapted to be selectively aligned with said ducts in a predetermined order, a throttle in said primary air passage for controlling the flow of an air- 'fuel mixture therethrough, a mixing chamber,

exhaust manifold heating means operatively associated with said primary air passage for heating the air-fuel mixture flowing therethrough, an auxiliary air passage adapted to by-pass said fuel supply means and said throttle and in communication with said primary air passage through said mixlng chamber, piston means responsive to the speed of the air flow through said air in- Y take adapted for, dividing the total air supply required in any stage of engine operations above idling speed and below the maximum potential engine speed into predetermined proportions of primary and auxiliary air supplies, said piston means also operatively associated with said valve and secondary fuel supply means comprising aplurality of interconnected fuel storage ductsopen to atmospheric pressure through a common orifice and to a source oi fuel through a second common orifice, said ducts havmg discharge ports in said primary air passage on the engine intake manifold side of said throttle and one of said ducts being in communication with said primary air passage through valve means therein adapted for preventing the passage of fuel therethrough in response to suction applied through its discharge port superior to the predetermined normal engine suction, and another of said ducts bein in communication with said primary air passage through valve means adapted to remain open in response to suction inferior to the predetermined normal engine suction.

- and a valve member having openings adapted to be selectively aligned with said ducts in a predetermined order, means operatively associated with said primary air passage for heating the airfuel mixture flowing therethrough, automatic I actuating means responsive to the engine suction induced air flow through said air inlet for simultaneously operating said fuel valve member and said air valve means for dividing the air through said inlet into primary and auxiliary air supplies and for actuating said fuel valve member for maintaining throughout engine operations above idling and below maximum potential engine speed a predetermined ratio of air-fuel mixture at said outlet by progressively uncovering fuel outlets in a preselected order in accordance with the speed of air flow through said inlet.

'7. In combination in a carburetor for an internal combustion engine, having an air inlet through which the total air must pass and an outlet adapted to be connected to the manifold of an engine, a mixing chamber, a primary air passage between said inlet and said outlet, an auxiliary air passage between said inlet and said outlet and communicating with said primary air passage through said mixing chamber, air valve means for controlling the communication between said inlet and said auxiliary air passage, primary fuel supply means opening into said primary air passage between said air inlet and said mixing chamber, a throttle in said primary air passage between said primary fuel supply means and said mixing chamber, secondary fuel supply means opening into said primary air passage on the outlet side of said throttle, means operatively associated with said primary air passage for heating the air-fuel mixture flowing therethrough, automatic actuating means responsive to the total engine-suction induced air flow through said air inlet for simultaneously controlling said primary fuel supply means and said air valve to constitute an over rich air-fuel mixture in said primary air passage under the contol of said throttle valve which is thereafter heated by said heating means and mixed with auxiliary air in accordance with the operation of said actuating means, said secondary fuel supply means comprising a plurality of interconnected fuel storage ducts, a source of fuel for said ducts,

its discharge port superior to the predetermined normal engine suction, and another of said ducts being in communication with said primary air passage through a valve adapted to open in response to suction inferior to the predetermined normal engine suction.

8. In combination, in a carburetor for an internal combustion engine, having an air inlet through which the total air must pass, and an outlet adapted to be connected to an engine manifold, a mixing chamber, a primary air passage between said inlet and said outlet, an auxiliary air passage between said inlet and said outlet and communicating with said primary air passage through said mixing chamber, air valve means for controlling the communication between said inlet and said auxiliary air passage, primary fuel supply means opening into said primary air passage between said air inlet and said mixing chamber and comprising a plurality of fuel metering ducts of predetermined size and a valve member having openings adapted to be selectively aligned with said ducts in a predetermined order, a throttle in said primary air passage between said primary fuel supply means and said mixing chamber, means operatively associated with said primary air passage for heating the air-fuel mixture flowing therethrough, piston means responsive to the total engine suction induced air flow through said inlet for simultaneously operating said primary fuel valve member and said air valve means for dividing the air through said inlet into the primary and auxiliary air supplies and for selectively opening said fuel metering ducts in such a manner and order as to provide fuel ducts of total area increasing in inverse relation to the velocity of suction induced air flow above idling speed through said inlet and a secondary idling fuel supply means communicating with said primary air passage on the engine intake side of said throttle.

9. In combination, in a carburetor for an internal combustion engine, having an air inlet through which the total air must pass, and an outlet adapted to be connected to an engine manifold, a primary air passage between said inlet and said outlet, a throttle in said primary air passage, an auxiliary air passage between said inlet and said outlet, air valve means for controlling the communication between said inlet and said auxiliary air passage, primary fuel supply means opening into said primary air passage comprising a plurality of fuel ducts and a fuel valve member for controlling the opening of said ducts, automatic actuating means responsive to the engine-suction-induced air flow through said inlet for simultaneously operating said fuel valve member and said air valve means for dividing the air through said inlet into primary and auxiliary air supplies and for selectively opening said fuel ducts of a total area which varies at a rate in inverse relation to the speed of suction induced air flow through said inlet, and a normally open idling fuel supply channel communicating with said primary air passage on the engine intake side of said throttle, said idling fuel supply channel having valve means for preventing passage of fuel therethrough in response to engine suction applied to said outlet in excess of that prevailing during predetermined normal engine idling speed.

10. In a carburetor for an internal combustion engine, having an air inlet through which the total air must pass and an outlet adapted to be connected to an intake manifold, a primary air passage between said inlet and said outlet, '1 throttle in said primary passage, auxiliary air passage between said inlet and said outlet, air valve means for controlling the communication between said inlet and said auxiliary air passage, primary fuel supply means opening into said primary air passage between said throttle and said outlet, automatic actuating means responsive to the total engine-suction air flow through said inlet for simultaneously controlling said primary-fuel supply means and said air valve means to constitute an over-rich air-fuel mixture in said primary air passage under the control of said throttle valve which is. thereafter mixed with auxiliary air in accordance with the operation of said actuating means, and idling fuel supply means having an outlet opening into said primary air passage on the engine side of said throttle, said idling fuel supply means having air and fuel orifices adapted for delivering an air-fuel mixture of proportions predetermined for idling purposes to said primary air passage on the engine side of said throttle and having automatic means adapted for shutting off said idling fuel supply when the degree of vacuum at said idling fuel outlet exceeds the normal degree of vacuum during predetermined idling speed.

'11. In combination, in a carburetor for an internal combustion engine, having an air inlet through which total air must pass and an outlet adapted to be connected to the manifold of an engine, a mixing chamber, a primary air passage between said inlet and said outlet, an auxiliary air passage between said inlet and said outlet and communicating with said primary air passage through said mixing chamber, air valve means for controlling the communication be-' tween said inlet and said auxiliary air passage, primary fuel supply means opening into said primary air passage between said air inlet and said mixing chamber, a throttle in said primary air passage between said primary fuel supply means and said mixing chamber, automatic piston actuating means responsive to the total engine suction induced air flow through said air inlet for simultaneously controlling said primary fuel supply means and said air valve means for forming an air-fuel mixture of predetermined air and fuel proportions, a secondary fuel supply means opening into said primary air passage on the outlet side of said throttle comprising a normally open idling air-fuel mixture supply channel and a normally closed excess air-fuel mixture supply channel, both of said channels being subject at all times to the pressure existing at said outlet, said idling air-fuel supply channel having valve means for preventing fuel passage therethrough, in response to engine suction which exceeds the predetermined normal suction'at engine idling speed, said excess air-fuel supply channel having valve means adapted to open said channel in response to predetermined engine suction inferior to engine suction at normal idling speed, both of said secondary fuel supply channels connected to interconnected fuel storage ducts and to a common air supply orifice having access to atmospheric pressure, a source of fuel for said ducts and a common fuel oniflce connecting said ducts with said source of fuel, said source having a predetermined level between said fuel orifice and said air orifice, said air orifice and said fuel orifice adapted to be adjusted for producing an idling air-fuel mixture, whereby said idling duct is adapted to supply to said primary air passage an initial jet of fuel at the starting of the engine followed by a predetermined airfuel mixture proportioned for normal idling purposes and supplies no fuel during vacuum conditions in the engine intake above that existing at normal idling speed and the excess airfuelsupply channel supplies an initially rich airfuel mixture followed by. an air-fuel mixture for pressure conditions in said engine intake above those existing during normal engine operations, such as when said throttle is suddenly opened to accelerate the engine or when the engine is under heavy load.

12. A carburetor for an internal combustion engine having an air inlet and an outlet adapted to be connected to the manifold of an engine, primaryair passage between said inlet and said outlet, fuel supply means comprising a plurality of fuel ducts of predetermined areas opening into said primary passage and a fuel valve member for controlling the opening of said ducts, an auxiliary air passage adapted to by-pass said fuel supply means in communication with said'primary air passage at a' point between and said outlet, piston means automatically responsive to engine suction and for controlling said fuel valve member to open fuel discharge orifices of a total area varying in inverse relation to the suction-induced air flow through said inlet. v

13. A carburetor for an internal combustion engine having an air inlet and outlet adapted to be connected to the manifold of an engine, a primary air passage between said inlet and said outlet, a mixing ,chamber, an auxiliary air passage between said inlet and said outlet and communicating with said primary air passage through said mixing chamber, a throttle in said primary air passage, a fuel supply means including fuel metering means in 'said primary air passage between said throttle and said mixing chamber, an air valve for controlling communication between said inlet and said auxiliary air passage, means in said inlet responsive to the total engine suction induced air flow for operating said air valve and said fuel metering means whereby an over-rich air-fuel mixture is produced in said primary air passage which is later mixed with auxiliary air in said mixing chamber in accordance with the operation of said total air responsive means and auxiliary engine suction responsive means for modifying said total air responsive means to facilitate initial movement and for retarding the final movement of said total air responsive means.

14. A carburetor as set forth in claim 2 having a normally open idling air-fuel mixture supply channel opening into said primary air-fuel passage between said throttle and said outlet and a valve in said channel exposed at all times to engine suction applied through said outlet and adapted for closing to prevent the passage of fuel therethrough in response to suction at said outlet exceeding that at predetermined normal engine idling speed. 1

15. In a carburetor, the combination as set forth in claim 13 including a secondary fuel supply means communicating with said primary air passage between said throttle and said outlet,

said fuel supply means induced total supply spouses .a source of fuel, a plurality of interconnected storage ducts communicating with said source of fuel through a common'fuel orifice, one of said fuel ducts being connected respectively to each of said air-fuel passageways and another of said ducts being open to atmosphere through an air orifice, said fuel orifice and said air orifice adapted to predetermine the air-fuel mixture for normal idling operations, said ducts being adapted to supply to said idling passageway an initial jet of fuel at starting of the engine followed by a predetermined idling air-fuel mixture proportioned-for normal idling purposes and to, supply 'no fuel during vacuum conditions in the engine intake above that existing at normal idling speed and said excess air-fuel supply channel to supply an initially rich air-fuel mixture followed by an air-fuel mixture for' pressure conditions in said engine intake above those existing during normal engine operations such as when said throttle is suddenly opened to accelerate the engine or when the engine is under heavy load.

16. In combination, in a carburetor for an internal combustion engine having an air inlet through which the total air must pass and an outlet adapted to be connected to the intake manifold of an engine, a primary air passage between said inlet and said outlet, a mixing chamber, an auxiliary air passage between said inlet andsaid outlet and communicating with said primary air passage through said mixing chamber, air valve means for controlling communication between said inlet and said auxiliary passage, a throttle in said primary passage between said inlet and said mixing chamber, primary fuel supply means opening into said primary passage between said mixing chamber, means operatively associated with said primary air passage between said throttle and said outlet for heating the air-fuel mixture flowing through said primary air passage, automatic actuating means responsive to the total engine suction induced air flow through said inlet for simultaneously controlling said primary fuel supply means and said air valve means to constitute an over-rich air-fuel mixture in said primary air passage under the control .of said throttle valve to which is thereafter added auxiliary air in said mixing chamber in accordance with the operation of said automatic actuating means, an idling fuel supply means opening into said primary air passage on the outlet side of said throttle, said idling fuel supply means having air and fuel orifices adapted for delivering an air-fuel mixture of proportions determined for idling purposes to saidprimary air passage on the engine side of said throttle and having automatic valve 22 ing the primary air-fuel mixture with additional air. a primaryair passage between said inlet and said mixing chamber, fuel supply means communicating with said primary air passage, a throttle in said primary air passage between said fuel supply means and said mixing chamber, exhaust manifold heating means operatively associated with said primary air passage for heating the resulting primary air-fuel mixture, an auxiliary air passage between said inlet and said mixing chammr adapted to bypass said fuel supply.

means, said throttle and said heating means, and automatic actuating means responsive to the engine suction induced total air flow for simultaneously varying the discharge of fuel into the primary air passage and for controlling the communication between said inlet andsaid auxiliary air passage for-adding auxiliary air to said heated air-fuel mixture in said primary air passage, said actuating means comprising a cylinder adjacent said air inlet and a, piston, said piston having a hollow main portion and a hollow reduced cylindrical neck portion and a disk end portion attached to said neck portion and spaced from said main body portion, said disk portion and said neck portion having openings therein whereby said inlet is in open-communication with said primary air passage at all times, resilient means normally urging said piston toward an so extreme position toward said inlet, a port in the means for shutting off said idling fuel supplyat said outlet exceeds when the degree of vacuum during predeterthe normal degree of vacuum mined idling speed.

17. In combination in a carburetor for an internal combustion chamber having an air inlet and an outlet adapted to be connected to the manifold of anengine, a mixing chamber for mix- I side of said cylinder communicating with said auxiliary air passage and adapted to be covered by the main body portion of said piston when the latter is moved to said extreme end position by said resilient means, said main body portion of said piston progressively uncovering said port when said piston is moved under the influence of incoming air to thereby divert a portion of the incoming air into said auxiliary air passage.

18. A combination as set forth in claim 17, and engine-suction responsive means connected to said piston adapted to modify the action of said resilient means and the air flow against said piston thereby facilitating the initial opening and of retarding the final closing movement of said piston under predetermined engine-suction conditions.

19. The combination as set forth in claim 1'7 in which said inlet comprises a choke tube attached to the inlet end of said cylinder, said tube having a web provided with a concentrically disposed cylindrical recess and a central tubular extension coextensive with said recess forming a second cylinder, 9, second piston adapted to operate in said cylinder and attached to said first piston, the closed end of said second cylinder being connected to the outlet of said carburetor through a conduit having a, restricted orifice therein and having a check valve adapted to open in response to engine suction, a second check valve connected to said conduitvbetween said outlet and said second cylinder adapted to close in response to engine suction whereby said second cylinder and piston modify the action of said first cylinder and piston to facilitate the initial opening and the final retarding movement of said second piston under predetermined engine suction conditions.

20. In combination in a carburetor for an internal combustion chamber having an air inlet and an outlet adapted to be connected to the manifold of an engine, a'mixing chamber for mixing the primary air-fuel mixture with additional air, a primary air passage between said inlet and said mlxing'chamber, fuel supply means communicating with said primary air passage, a

23 throttle in said primary air passage between said fuel supply means and said mixing chamber, exhaust manifold heating means operatively as-' sociated with said primary air passage for heating the resulting primary air-fuel mixture, an auxiliary air passage between said inlet and said mixing chamber adapted to by-pass said fuel supply means, said throttle and said heating means, and automatic actuating means responsive to the engine suction induced total air flow for simultaneously varying the discharge of fuel into the primary air passage and for controlling the communication between said inlet and said auxiliary air passage for adding auxiliary air to said heated air-fuel mixture in said primary air passage, secondary fuel supply means opening into said primary air passage at the outlet side of said throttle comprising a chamber, a conduit connecting said chamber to the outlet side of said throttle, a closure member sealed to one end of said chamber comprising a disk-like element having attached thereto a cylinder block extending into said chamber and having a blind end minor cylindrical bore therein facing said disk-like element, a first piston adapted to operate in said minor cylindrical bore, a cylindrical casing sealed to said closure member and having an internal major bore serving as a second cylinder, a second piston adapted to operate in said second cylinder, said pistons being connected together to move in unison, plurality of apertures in said disk-like element providing communication between said second cylinder and said chamber outside of said first cylinder and one face of said second cylinder adapted to seat over said apertures in sealing engagem nt, resilient means between the blind end of said iirst cylinder and said first piston adapted to urge said second piston away from seating engagement over said apertures, a restricted orifice between the blind end of said first cylinder and said chamber. a conduit between a source of fuel and said second cylinder, said resilient means being so calibrated as to permit said second piston to close said apertures during vacuum conditions in said engine corresponding to normal engine op erating conditions but responsive to engine suction inferior to that at normal engine operating speed to move said second piston away from said orifices to permit excess fuel to enter said primary air passage.

OLAF OSWALD.

REFERENCES CITED The following references are of record in the file of this patent:

UNI'I'ED STATES PATENTS Number Name Date 1,247,478 Young Nov. 20, 1917 1,258,389 Bergen Mar. 5, 1918 1,317,011 Fisher Sept, 23, 1919 1,405,777 I Good Feb. 7, 1922 1,534,808 Renner Apr. 21, 1925 1,620,645 Good Mar. 15, 1927 1,690,962 Allen Nov. 6, 1928 1,913,321 Allbright June 6, 1933 1,944,397 Berry Jan. 23, 1934 2,004,869 Hogg June 11, 1935 2,070,598 Hewitson Feb. 16, 1937 2,134,667 Leibing Oct. 25, 1938 2,223,919 Oswald Dec. 3, 1940 2,327,592 Chisholm Aug. 24, 1943

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