US1825381A

US1825381A - Multiple carburetor charge forming device

Info

Publication number: US1825381A
Application number: US53338A
Authority: US
Inventors: Horace W Asire
Original assignee: General Motors Research Corp
Current assignee: General Motors Research Corp
Priority date: 1925-08-29
Filing date: 1925-08-29
Publication date: 1931-09-29
Anticipated expiration: 1948-09-29

Description

Sept. 29, 1931. H. w. ASIRE 1,825,381

MULTIPLE CARBURE TOR CHARGE FORMING DEVICE Filed Aug. 29, 1925 3 Sheets-Sheet l Sept. 29, 1931.

H. w. ASIRE 1,825,381

MULTIPLE CARBURETOR CHARGE FORMING D EVICE I Fil 1925 3 Sheets-Sheet 2 F? 1 i 83 1 f g Z Q78 '87 a4; I a as Sept. 29, 1931. w, AslRE 1,825,381

MULTIPLE CARBURETOR CHARGE FORMING DEVICE Filed Aug. 29, '1925 3 Sheets-Sheet 3 primazy air ai Fig.1 is a 7 Patented 29, 1931 Q UNITEDSTATES PATENT OFFICE gnome]: w.

ASIDE, or narrow, omo, assmnon zro emrnm norons nnsmnon conrom'rron, or DAYTON, onro, aconromrron or nmwm I I alumnus omnuamoacnanen resume nnv'rcn Application Med Aug: 29; ms. Serial no. saass.

"This invention relates to charge forming devices for multicylinder internal combustlon engines.

It isone of the objects of the present in- I 'vention'to secure more even distribution of fuel charge to the various engine cylinders, in order that the engine. may start more readilyand operate more eificiently. In the pres:

ent invention this, object is accomplished a by providing a unitary structure adapted to be attached to the intake ports of the engine and comprising a plurality of carburetors, each directly communicating with an engine intake port, said structurehaving a common air inlet for all of the carburetors and a single. operating member for controlling all of the throttle valves of the carburetors.

Further objects and advantages of the present invention will be a parent from the folgd' lowing description, re erence being had to the accompanying drawings, wherein a preferred form of embodiment of the present invention is clearly shown.

In the drawings:

lan view of th form of the present inventlon shown attached to an internal combustion engine which is partly in plan and partly in section; I 1

Fig. 2 is a side elevation of the apparatus at shown in Fig. 1; l

Figs. 3 and 4 are sectional views taken respectivelyon lines 33 and 4-4 of Fig. 1, these viewsbeing on a larger scale than Figs.

Y 1 and .2.v

35' Fig. 5 is a modified form of primary carbureting device which may be substituted for the form shown in Fig. 3.

The drawings indicate an internal combustion engine having a plurality of cylinders 4.3 20, each provided with an inlet valve 21 and an exhaust valve 22. Each exhaust valve communicates with an exhaust outlet pipe 23 and each pair of intake valves 21 is served by a common intake pipe 24.

V The unitary charge forming device which is adapted to be attached by screws 25 to the intakes 24, comprises an air manifold which provides air passage having a common inlet 31 (see Fig. 4), and branches 32, each communicating with an engine intake port 24 and each provided adjacent the intake with a,

'Venturi member 33, which is retained by a screw 34 and lock nut 35. Each branch 32 of the air manifold 30 has a constant level fuel reservoir 36 locateddirectly above the Venturi member 33. A fuel duct 37, preferably castintegral with manifold 30, communicates with all of the reservoirs 36, having one end attached by a coupling 38 with a fuel supply pipe 39. The fuel reservoir 36 includes a wall which is common to a portion of the duct 37 and this wall is provided with a hole 40 leading into a recess 41, which is threaded to receive a valve seat member 42 having an opening 43 adapted to be closed by a valve 44. Valve 44 is carried by a lever 45 secured to a float 46 and supported by a pivot pin 47 supported by a reservoir cover late 48 retained in position by screws 49. each float bowl 36 a duct 50 extends above the normal level of fuel and is in communication with a hole 51 in the throat of the Venturi member 33. Cover '48 provides a duct 52. for connecting the duct 50 with outside atmosphere. A fuel pipe 55 having at its lower end a fuel-metering orifice 54 communicates'with the passage 52 and is threadedly attached to the cover 48. The flow of air into the passage 52 is limited by an air-flow metering plug 56. When the cover 48 is assembled upon the float bowl 36 the throat of venturi ithin 33 is placed in communication with outside Referring to Fig. 4, the common air inlet 31 is controlled by an automatic valve mechanism which comprises a valve frame 70 having an air inlet 71 and an outlet 72 commu-- nicating with the common air inlet 31. Adjacent the outlet 7 2 the frame 70 is provided with a valve seat 7 3. which can'be closed by a valve 74 attached to a stem 75 having its upper end connected to a dash pot piston 7 6.

Piston 7 6 slides within a cylinder 7? which is contained within a cylindrical recess 78 by a spring clip 7 9 which is attached to the frame 70 by a screw 80 and spaced from the frame 70 by a s acing tube 81. A coil spring 82 interposed between a s ring seat cup 83 and the head of the piston 6 tends to retain the valve 74 upon its seat 73. The valve 74 is opened automatically by the suction of the engine against the urge of the spring 82.

The dash pot piston 76 prevents fluttering of valve 74 and stabilizes its position according to engine speed and throttle position. The piston 76 is provided with a central aperture 76"which permits the escape of air downwardly therethrough during upward travel of the piston. However during the downward travel of the piston, the aperture 76' is closed by the check valve 76", as will be clear from viewing Fig. Therefore. the effect of the clash pot will beto damp the opening movement of air valve 74 to a much greater degree than the closing movement thereof. Thus when the throttle ,valves 60 are suddenly closed to idling position the air valve 7 4 is permitted to close quickly enough to maintain sufiicient depression in the air manifold to cause the proper rich fuel mixture to be drawn through the duct 50.

The automatic operation of the main air valve 74 is modified by a manually actuated lever 84 attached to a shaft 85, which extends across the valve frame 70 and carries within said frame a lever 86 having a forked end envary the position of the sleeve 88 and seat cup 83 in order to var the compression in the spring 82 and there y vary the degree of opemng of air valve 7 4 for a iven depressionin the air manifold 30. y increasing the compression of-spri-n 82 less air is admitted through valve 74 for a given depress sion in the air manifold 30 and hence a richer fuel mixture is drawn into the engine whenever desired. The suction of the engine causes rimary air to enter the plug 56 and liquid el to flow upwardly through the duct 55 and form an overrich mixture of air and fuel in duct 50 which is drawn into the venturi 33 and mixes with the flow of air through the branch 32. The float 46 operates in the usual manner to close the fuel inlet passage'43 and maintain the level of fuel in the bowl 36 substantially constant.

Fig. 5 illustrates a modified form of primary carburetin device which may be used with the air manifold 30 in place of the form shown in Fig. 3. In Fig. 5 the cover plate 900i the float bowl 36 has a fuel well 91 and a fuel mixture duct 92 which registers with the duct 50 extending upwardly through the float bowl 36. Atmospheric air enters the restricted air inlet tube 93 which extends downwardly within the duct 92 leaving an annular has an annular groove 102 which registers with the duct 50. A series of holes 103 form a communication between the upper portion of the groove 102 and the throat of the venturi 101. The lower half of the groove 102 forms a semi-annular well 104 which communicates with the center of tile .Venturi throat through the stand pipe 105.

The operation of the device ofFig. 5 is as follows: I

At slow engine speeds, say that corresponding to a car speed of'15 miles per hour, the depression in the air manifold '30 will create a depression in duct 92 which in turn will cause air to enter the primary air inlettube 93 and liquid fuel to be drawn up through pipe 97, out through low speed fuel orifice 99 into the well 91, and thence through the low speed fuel jet 95 forming a rich mixture of air and fuel in duct 50. This rich mixture is drawn through the holes 103 and there sprayed into the air passing through the venturi 101 to form a mixture of the proper proportions for the engine when running at the slower speeds. If now the throttle 60 be opened to cause the engine speed to materially increase, the increased depression in air manifold 30 and the increased air flow through the venturi 101 will greatly increase the de ression in duct 92 which in turn will cause uel to be drawn up into well 91 through both orifices 99 and 100 faster than it can flow out through the jet 95 and hence the fuel level in well 91 will rise until it also flows through the larger high speed jet 96. The combined fuel flow through both jets 95 and 96 is such as to maintain the proper. fuel and air ratio to the engine at the higher speeds thereof.

Now if the throttles 60 be closed to materially reduce the engine speed while the fuel well 91 is full, the air flow through venturi 101 and rimary air inlet 93 will be greatly reduced But the greater part of the fuel in well 91 will run out through a jet 95 by gravity and flow down through

ducts

92 and 50 and fill the semi-annular well 104 since there will not be suflicient suction to cause this superfluous liquid fuel to enter holes 103 mixture passing to theengme for a few moments to give a quick acceleration to the englue. The well 104 therefore serves as an accelerating well and is filled by the dumping of well 91 each time the engine speed is materially reduced by closing the throttles.

Thus the well 104 is always ready to deliver 1 an accelerating rich mixture when the throt- .opened to admit air according tles are suddenly opened.

An important feature of this primary carburetor- IS the extension of the primary air inlet tube 93 beyond both the fuel jets 95 and 96. Any variation in the flow of fuel through these jets due to turbulent effects in the air stream is thus avoided and hence more accurate and uniform metering of the liquid fuel obtained.

One of the important advantages of the present invention is that of more evenly distributing fuel charge to the various cylin-- ders. Each engine intake port is provided with a carburetmg .device which is situated relatively close to the calinder intake valves. Since there is very lit e chance of uneven distribution occurrin between a pair of intake valves, it is evi ent that the distribution will be more uniform than in the case where a single carburetor is used to supply fuel charge to four or more cylinders.

Another advantage lies in the simplicity of structure, enabling the device to be assembled on an engine in a simple manner, and

to be connected with the fuel line by only one pi e connection.

Vhile the forms of embodiment of the present invention as herein disclosed, constitute referred forms, it is to be understood that ot er' forms 'might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. In a charge forming device for a multicylinder internal combustion engine having a plurality of intake ports, an air manifold having a branch leading to each engine intake port and a common main air inlet, a spring closed valve in said main air inlet which is to the depression in said manifold, an in ividual'carburotor for supplying fuel to each of said branches relatively close to said engine intake ports, a throttle valve in each branch on the engine side of the point of fuel admission, common means for concurrently actuating all of said throttle valves, and manual means whereby the operator may at will ch the spring tension on said spring close valve to vary the amount of air admit- 9 ted to said manifold and hence equally vary the fuel and air ratio drawn into each of said engine intake ports.

2. In a charge forming device for a multicylinder internal combustion engine having a plurality of spaced intake ports, an airmanifold having a'branch leading to each engine I which is opened to admit air according to the a depression in said manifold, an individual prlmary carburetor associated with each manifold branch, said carburetor being located closely adjacent tothe engine intake port, and adapted to supply an overrich mixture of fuel and air to its associated manifold branch close to said port, a throttle valve in each manifold branch for controlling the flow therethrough, and common actuating means for said throttles.

3. In a charge forming device for a multicylinder internal combustion engine having a plurality of spaced intake ports, an air manifold having a branch leading to each engine intake port and a common main air inlet, a spring closed valve in said main air inlet which is opened to admit air according to the depression in said manifold, a plurality of individual carburetors, one for each branchvof the manifold and each of which is provided with a constant lever fuel chamber, said carburetors being located closely adjacent the engine intake ports and adapted to supply a mixture of fuel and air to the manifold branches close to said ports, a throttle valve in each manifold branch for controlling the flow therethrough and common actuating means for said throttles.

4. In a charge forming device for a multicylinder internal combustion engine having a plurality of spaced intake ports, an air manifold having a branch leading to each engine intake port and a common'main air inlet, a spring closed valve in said main air inlet which is opened to admit air according to the depression in said manifold, a plurality of individual carburetors, each of which is provided with a constant level fuel chamber, said carburetors being sup orted by the manifold branches closely adjacent the engine intake ports and adapted to supply fuel to said branches close to said ports,

a plurality of spaced intake ports, an air manifold having a branch leading to each engine intake port and a common main air inlet, a spring closed valve in said main air .inlet which is opened to admit air according to the depression in said manifold, a

plurality of individual carburetors, each of which is provided with a constant level fuel chamber, said carburetors being cast integral with the manifold branches closely adjacent the engine intake ports and adapted to supply fuel to said branches close to said ports, a throttle valve in each manifold branch 4 mama for controlling the flow therethrou h, and common actuatin means for said v ves.

6. In a charge orming device for a multicylinder internal combustion engine having a plurality of intake orts, an air manifold having a branch leading to each engine in take port and a common main air inlet, an automatically closed valve in said main air inlet which is opened to admit air according to the depression in said manifold, an individual primary carburetor supported by each manifold branch and adapted to supply an overrich mixture of fuel and air to each manifold branch, the amount of mixture su plied to each branch being up roximatey directly in accordance with the epression 1n said branches, a throttle valve in each manifold branch and common actuating means for said throttles.

7 In a charge forming device for a multicylinder internal combustion engine having a plurality of intake ports, an air manifold having a branch leading to each engine intake port and a common main air inlet, an automatically closed valve in said main air inlet which is opened to admit air according to the depression in said manifold, an individual primary carburetor supported by each manifold branch adjacent the engine intake port and adapted to supply an overrich mixture of fuel and air to each manifold branch close to said port, the amount of mixture supplied to each branch bein a proximately directly in accordance with the depression in said branches a throttle valve in each manifold branch and common actuating means for said throttles.

In testimony whereof I hereto afiix my signature.

HORACE W. ASIBE.