US2260408A - Apparatus for increasing economy of carburetor engines - Google Patents

Description

Oct. 28, 1941. H. c. SEFFKER 2,260,408

APPARATUS FOR INCREASING ECONOMY OF CARBURETOR ENGINES Filed Nov. 2, 1938 2 Sheets-Sheet 1 I 65 f v I 67v 2 W INVENTOR HERMAN C. 5 FKER Oct. 28, 1941.

H. C. .SEFFKER APPARATUS FOR INCREASING ECONOMY OF CARBURETOR ENGINES 2 Sheets-Sheet? Filed Nov. 2, 1938 5! 'TNVENTOR HERMAN C. 55mm? Patented Oct. 28, 1941 APPARATUS FOR INCREASING ECONOMY OF CARBURETOR ENGINES Herman G. Seflker, Freeport,'N. Y.

Application November 2, 1938, Serial N 0. 238,475 1 Claim. (01. 48-180) The invention relates to a device for regulating the vacuum applied to the fuel distributin means in an internal combustion engine, and is more particularly concerned with means for so regulating the vacuum applied to the carburetor of an internal combustion engine that an excessive injection of fuel and the attendant losses in economy are avoided. The invention is par ticularly described in connection with its application to bus or truck engines, where high temperatures and frequent acceleration and deceleration occur, but is also applicable to other engines in which there is a variation in the vacuum applied to the fuel controlling device.

In the operation of motor vehicles, when the motor is running at a substantially constant speed, such as when running under normal conditions or when idling, the engine applies a vacuum of about 19 inches of water to the carburetor. Under such conditions the required amount of fuel is drawn into the intake'manifold and there distributed to the various cylinders.

The carburetor of an internal combustion engine normally is provided with a butterfly or other valve of such a size as to leave an opening through which a small quantity of fuel may be drawn when the motor is idling, thus avoiding stalling of the motor on deceleration.

When the motor is suddenly decelerated for example from the normal driving speed to idling speed, the vacuum builds up very rapidly to about 23 to 25 inches. It then takes an appreciable time for the vacuum to return to normal. During this period of high vacuum, an excessive amount of fuel is drawn into the intake manifold, resulting in a loss of fuel and a dilution of the crank case oils and other losses in economy. The high vacuum also tends to draw lubricating oil up into the cylinder where it combusts, causing further losses in economy and undesirable odors. V

Attempts have been made heretofore to overcome this objection by the use of mechanically actuated valves operating in conjunction with the throttle. Such controls, however, are subject to the disadvantage, among others, that they are not actuated in accordance with the objectionable tendency to be overcome.

Attempts have also been made to provide for the admission of auxiliary air by valves responsive to increased vacuum occurring on deceleration. Certain arrangements heretofore devised for this purpose have been improperly located to produce the desired operating efliciency.

Others are objectionable also because the air is 55 other and to the carburetor jets.

between the centers of the two throats, or beadmitted at a single point or in a manner which does not provide a smooth and responsive regulation of the vacuum. It is an object of the present invention to provide means for control- :ling the vacuum in an intake system for internal combustion engines, but which overcomes the disadvantages referred to.

A general object of the invention is to provide improved means for regulating the vacuum applied to the carburetor or other fuel supply. It is also an object to provide an arrangement whereby the improvement will be effective equally upon all cylinders of the motor and will be regulated in accordance with the objectionable tendency to be overcome.

A further object is to provide means for controlling the expansion of earburetedfuel before it enters the manifold to provide increased economy of operation either apart from, or in conjunction with, other means for'regulating the vacuum. I Y

Other objects and advantages of the invention will appear as the description proceeds.

I have discovered that marked operating economies can be effected, and other improvements obtained, by providing an intake system which comprises a Venturi throat designed to produce two stages of expansion. A similar result can be obtained with the use of two Venturi throats suitably positioned with respect to each The distance tween the starting points of the two expanding stages, appears to be critical in the attainment of optimum conditions of operation. The, tests um of 19 inches of water. This distance appears,

moreover, to remain substantially constant for a given pressure differential even with different sizes of carburetor, i. e., with carburetor venturis of different diameters. that the ratio between the normal vacuum in' inches of water to the distance in inches between the starting points of the two expanding stages preferably should be maintained at about 4 to 1. This ratio is of course susceptible to some variation by reason of differences in carburetor design, but it will be found that best results are obtained if the aforesaid ratio be maintained at between 3.5 to 1 and 5 to 1.

I have found, moreover, that the second, or upper, expanding stage should be located beyond, or above, the throttle plate or other throttle Thus it appears valve. In accordance with my invention, the auxiliary air which is admitted when the vacuum increases to a predetermined amount (as upon rapid deceleration), is drawn in at a point adjacent the second or final expanding stage. This point is above the throttle valve and preferably at-or only slightly beyond-the starting point of the expanding stage referred to, i. e., in the throat of the ,Venturi passage.

In my preferred embodiment the auxiliary air is admitted around the periphery of a Venturi throat, as by means of a series of apertures distributed around the throat and leading to a common source of air through a vacuum-operated valve. Thus, when the vacuum reaches a. predetermined amount, the auxiliary air will be drawn in adjacent the point where the carbureted fuel enters the flnal stage of smooth, or controlled, expansion. I have found that in order to maintain the desired. ratio of air to fuel under conditions of abnormal vacuum such as encountered upon rapid more inches, this ratio is not maintained. I have discovered that the desired fuel ratio can be moreclosel-y maintained when the combined areas of the air inlet apertures in the Venturi throat ismade toequal about of the area of the throat; that is to say, the, preferred ratio of the throat area to the combined areas of the peripheral apertures is about 30 to 1., I

In the drawings,

Fig. 1 is a side elevational View of an internal combustion engine, showing the carburetor and intake manifold, and illustrating the application of my invention-thereto.

. Fig. Zis a plan view, partly in central horizontal section (as indicated at 22 in Fig. 3), illustrating an auxiliary Venturi throat and auxiliary air inlet device constructed in accordance with the invention, and adapted to the practice of my novel method; Fig. 3 is a side elevational view of the same device, showing the Venturi throat in verticalsection as indicated at 33 in and cooperating vacuum valve 6 are shown in more detail in Figs. 2, 3, and 4 to which reference will now be made. In the embodiment illustrated, the device is clamped between the attaching flange 1 of the carburetor 2 and the cooperating flange 8 of the manifold riser 3 by means of stud bolts 9 passing through the flange 8 and apertures ID in the Venturi member 5, and being threadedinto the flange I. Suitable gaskets H may be arranged between the cooperating faces of the Venturi member 5 and flanges l and 8.

The Venturi member 5 has a throat l2, the walls of which flare outwardly from a central portion thereof both toward the point where they meet the entrance to the riser 3 of the manifold and where they meet the passage I3 of the carburetor. Leading into the Venturi throat l2 are a series of air. inlet passages M which are preferably inclined at a slight angle to a plane Fig. 2, Fig.4 is.-.a detail sectional view on the line 4 4 of Fig. 2.

Figs. 5 and 6 showanother embodiment of the invention, Fig. 5 being a vertical sectional view of a conventional carburetor to which the novel Venturi throat and auxiliary air device have been applied, and Fig. 6 being a bottom plan view of the Venturi tube.

Referring to the drawings, Fig. 1 shows a gen eral arrangement of apparatus embodying my invention as applied to an automobile engine. The

engine is indicated generally by the reference numeral I. The apparatus which will'be described is used in conjunction with a carburetor which is normal to the axis of the throat. These passages are distributed around the periphery of the Venturi: and their outlets are located in, a

plane which is adjacent the central portion of the throat or only slightly toward the; exit sidev thereof, i. e.,.at or only slightly beyond; the'starting point of the outward flare of the throat I 2 toward the exit side thereof. Thus air drawn.

in-through the passages M enters the'stream of carbureted fuel adjacent the point where the stream beg-ins to expand intothe riser 3. The

passages I 4 are joined by a'common header .55 whcih conveniently may be formed by milling a circular groove from either the upper or the lower faceof the member 5. In the embodiment illustrated, I have shownthis groove as being formed from the upper face of the Venturi membar. It will be observed that. the header I5 is sealed off at the upper face of the member 5 by the gasket II which, as previously described, isclamped between this upper face of the Venturi member and the complementary face of the manifoldriser flange 8. It will be understood that the header l5 can be formed in any other desired manner, although it is preferable to employ the construction just described because of its simplicity and ease of fabrication. It is particularly advantageous to have the passages l4 distributed around the periphery of the Venturi. throat, and the location of these passages in the throat is important in attaining certain of the objects of the invention. I

Apassage l6 joins the header I5 at ll, this passage extending outwardly through the side',

walls of the member 5-. This passage H5 preferabl -y istapped to receive a threaded nipple It or other suitable connection for the vacuum controlled valve 6 which now will be described.

In accordance with my preferred construction,

the vacuum operated air inlet comprises a pop pet-valve l9 arranged to resiliently seal the chamber 20 from the atmosphere. The poppet-v I valve l9 may conveniently be enclosed in a cylinder 2|: having a partition member 22 secured 2| may beprovided with a threaded connection to the head 26 which in turn may be threaded to receivethe nipple or other connection l8. Surrounding the stem of the valve I9 is a coil spring 27 seating at one end against the partition 22 and at the other end-against the spring. seat 28 which. loosely surrounds the stem of. the: valve. I

The position of the spring seat 28 is adjustable by means of the sleeve or nut 29 which has a threaded engagement with the end of the valve stem. If desired, the end of the valve stem may be slotted at 30 for engagement by ascrew-driver to facilitate adjustment of. the compression of the spring 21. A set screw 3| may be provided to maintain the sleeve 21 in its adjusted position. In my preferred construction, the cylinder 2| is of such a length as to permit the spring seat 28 and sleeve 29 to project beyond the end thereof to facilitate the adjustment of the compression of the spring. A cap 32 is arranged to be slipped over the end of the cylinder to completely enclose the valve mechanism once the adjustment has been made. The cap may be retained in place by means of the screw 33. The top of the cap 32 is formed by a screen 34, or other air filtering means may be attached at this point if desired.

In the embodiment illustrated in Figs. and 6, the invention is shown as applied to a typical carburetor for an automotive engine. In this construction, the carburetor venturi is replaced by a Venturi sleeve 35 formed as an integral part of the auxiliary Venturi air admission device 36. The sleeve 35 is provided at or near its lower end with a constricted throat portion 31 forming the main carburetor venturi. At its upper end, the sleeve is flared outwardly as at 38, which in effect forms an extension of the throat 37 providing a second stage of expansion for the carbureted fuel. The auxiliary air admission device 36 may be similar in construction to the member 5 described in connection with Figs. 2 and 3, em-

bodying inlet passages 39 and a header 40 communicating with a vacuum actuated valve mechanism of which only a portion of the casing is shown at 4|. The construction of this valve may be the same as has been described with reference to Figs. 2, 3 and 4.

In order that the invention may be more fully understood, I shall describe briefly the cooperating elements of the particular carburetor construction selected for illustration. It consists generally of a housing 42 provided with an air intake passage 43 and a fuel intake passage 44. The valve plate of the throttle is shown at 45, being mounted on a shaft 46 connected to the manual and foot controls. The air shutter plate 41 operated by the shaft 48 provides the usual strangler valve or choke. When the throttle plate is turned to open position, the vacuum created in the engine draws air in through the passage 43 and gasoline through the main jet 49 and cap jet 56. The gasoline supply is drawn from the reservoir 5| through the compensating jet 52, main jet regulator 53 and the communicaating passages 54 and 55. The fuel supply in the reservoir 5| is controlled by the valve 56 and cooperating float 51, the construction and operation of which is well known to those familiar with the art to which the present invention pertains. Fuel entering the carburetor at 44 passes through a cylindrical screen 58, discharging from the interior thereof to the passage 59.

An idling jet 60 may be provided, being arranged to draw fuel from the well 6| and to discharge it through the passages 62 communicating with the Venturi sleeve through an aperture 63 therein. The aperture 63 may be so designed and placed with reference to the throttle plate 45 as to permit fuel to be drawn in from the idling jet above the plate when the latter is in the closed position shown in Fig. 5. The idling mixture is controlled by a suitable needle valve 64 arranged in communication with anairpassage 65 communicating with the atmosphere. The passage 65 also communicates with the well 6| so' that fuel in this well will be open to the atmosphere. I

which in turn communicates with a passage 68 leading to the chamber for the idling valve 66.

As anexample of the application of the invention to a particular size of carburetor, I shall refer to the use of a normal 2 inch carburetor wherein the throttle plate shaft is positioned 3% inches above the lower .end of the venturi. This venturi is first removed and the diameter of the throttle platepassage in the upper carburetor body is enlarged sufliciently to receive the sleeve 35. For this particular carburetor, this sleeve will be provided with a Venturi throat 1 inches in diameter which at the exit side joins smoothly with a throttle plate passage 1 inches in diameter. The auxiliary air is admitted through ten radial pass-ages arranged as indicated in Fig. 2 each having a diameter of inch. It will be understood that the diameter of these passages is subject to variation; also that a greater number of passages of smaller diameter may be employed, or a lesser number of larger diameter. These radial passages intersect the throttle plate passage adjacent the start of the final stage of smooth expansion which, in this specific example, is located 4 inches above the center of the lower Venturi throat. Beyond this point the passage flares outwardly to a diameter of 2%; inches. It will be observed that in accordance with this specific example, a nominal 2 inch carburetor actually employs a 1 inch throttle plate and would nominally be described as a 1% inch carburetor. engine employing a nominal 2 inch carburetor of conventional construction would. in accordance with the present invention, employ a nominal 1 inch carburetor. It is essential that the admission of auxiliary air and the second expanding stage be located above the throttle plate.

Extensive tests of the invention described, as applied to automotive busses, have been made under my supervision and these tests indicate that the invention is capable of effecting an improvement in fuel economy of from 8% to with a substantial decrease in the quantity of obnoxious fumes discharged. The improvements which are obtained in accordance with the invention are particularly apparent as applied to street car busses or other vehicles where frequent acceleration and deceleration are encountered.

Those skilled in the art will understand that my invention can be employed in conjunction with carburetors and manifolds of widely varying design and construction. The auxiliary venturi and air admission device described in connection with Figs. 1 to 4 inclusive can be employed without making any changes in th carburetor or manifold, it being merely necessary to insert the device between the connecting flanges of the carburetor and manifold. The form illustrated in Figs. 5 and 6 may require some minor changes in the carburetor in order to maintain the desired distance between the carburetor venturi and the point of admission of the auxil iary air, or between the two stages of expansion. Thus the carburetor attaching flange may be removed or cut down to a certain extent, and, if

This means that an necessary,. the throttle plate passage in, the upper carburetor body may-be machined to enlarge the diameter thereof. Thevusual carburetor venturi.

is removed in order to permit insertion of the sleeve 35 with its Venturi throat 31.

It will also be understood that the auxiliary vventuri and air admission device shown in Figs.

5 and 6 may be built into carburetors as manufactured, in which case the sleeve 35 might be.

formed as an integral part of the upper carburetor body if so desired. Other modifications will suggest themselves to carburetor specialists of. limitation, and I have no intention of exaaeo eosc.

eluding" such; equivalents of the'invention set V forth,- or of portionsthereof, as fall within thepurview of the claim.

I claim:

An attachment for internal combustion engines which comprises a sleeve for insertion between: the carburetor and manifold, said sleeve having, a Venturi passage at its lower end and an outwardly flared-portion at its upper end,-apertu-resj arranged in communication with the interior. of the sleeve near its upper end,j an air inlet, valve-, and a header connecting said apertures to the air inlet valve, the sleeve having substantially) cylindrical smooth inner, walls throughout the a distance between the Venturi passage and the outwardly flared portion. I

HERMAN C. SEFFKER.

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