US2145730A - Carburetor - Google Patents

Description

Jan. 31, 1939. L H. MESSINGER. JR

CARBURETOR Filed Dec. 16, 1936 .53 IN V EN TOR. LESTER H. MESS\NGER,

A TTORNE).

Patented Jam 31, 1939 CARBURETOR Lester H. Messingcr, Jr., Trumbull, Conn, assignor to Messingcr Devices, Incorporated, Bridgeport, Coma, a corporation of Connecticut Application December 16, 1936, Serial No. 116,070

3 Claims.

'll 'hisv invention relates to new and useful improvements in carburetors. l

The invention providesmeans whereby the fuel discharged by a vacuum operated accelerator pump of a carburetor is forced by the pump into a receptacle and is drawn from said receptacle into an engine fed by the carburetor only while the carburetor throttlevalve is open and the engine is operating.

' The objects and advantages of the invention will. become apparent from a consideration of the following detaileddescription taken in connection with the accompanying drawing wherein there is shown a satisfactoryembodiment of the invention. However, it is to be understood that the invention is not iimitedto the details disclosed but includes all such variations and modifications as fall within the spirit of the invention and the scope of the appended claims.

In the drawing: Fig. 11 is a view partly in side elevation and partly in section showing a carburetor embodying the invention;

' Pig. 2 is a top plan view with parts broken away 25. and showing the invention;

Fig. 3 is a detail sectional view showing the carburetor fuel pump in discharged position;

Fig. '4 is a plan view of a receptacle employed; l 'ig. 5' is a vertical sectional view through such 30' receptacle; 1

' Fig. 6 is a detail sectional view through the economizer valve; and I check valve. 1 1

Referring in detail to the drawing a carburetor of; the down draft type is shown and the same comprises upperand lower sections ill and II I v secured together by screws i2. Within the carburetor is any or the usual venturi i3 located 40 above the throttle valve ll. In the float chamber Ii the fuel is maintainedat the level indicat- 'ed by the line it, being controlled by a float (not 1 shown) regulating the admission of gasoline or other fuel from any source through a connec- 45 tion ll.

The carburetor includes a vacuum operated v fuel pump generally designated l8 and comprising a chamber I9 constituting the pump cylinder. lWithin said cylinderithere is arranged pis 0 tons 20 and 2| connected by a rod 22 about which is coiled a spring 23 bearing at its respective ends against the piston 2t and a collar 24. In Fig. 1 spring "is compressed and the pistons 20 and 2| are in the positions occupied by them when the. 5 pump isloaded while inFig. 3 the pump is in discharged position. The spring 23 constantly tends to maintain the pistons in the positions of Fig. 3 and to return them to such positions when moved therefrom.

Through a cross passage 25 the upper end of 5 the pump cylinder II is placed in communication with the upper end of a vertical passage 26 which through a lateral branch 21 communicates I with the fuel passage 28 below the throttle valve It. Through the described passages suction from 10 the engine, while the latter is operating, will serve to exhaust air from above the piston 2| and the piston assembly, including pistons 20 and 2| and the rod 22, will be drawn upwardly compressing the spring 23 bringing about load- 15 ing of the pump. That is the suction moves the pump to the position of Fig. l.

A lateral passage 2! from the lower end of the pump cylinder communicates through a one way valve 30 with the float chamber ii. Valve 20 ll (see Fig. 7) is a flap valve including a valve proper designated ll opening downwardly and normally open to permit of the flow of fuel from the float chamber into the cylinder II. On downward movement of the piston 20 under the urg- 5 ing of the spring 28 pressure is applied to the fuel in chamber or cylinder I! and the passage 29 and valve 3| moves upwardly against its seat 32 preventing the fuel being forced back into the float chamber. 30

Below the, pump cylinder is a well 33 communieating by way of a passage 34 with a fuel jet or Fig. 7 is a detail sectional view through a nozzle 35 which in the present case is the power jet of the carburetor discharging in a small venturi "a. An economizer valve 38 is arranged to close of! communication between the jet 35 1 and the pump when the latter is in loaded position. valve includes a stem 31 carrying a valve proper ll (see Fig. 6) and the lower end portion of the stem is guided in a spider 39. Between the spider and the valve 38 a spring 4|] is disposed about the stem 31 and under normal conditions is eifective to maintain the valve on its seat. The arrangement is such that if there is no other escape for fuel as the pump dis- 4r charges then the valve 38 is forced open and the fuel .dischargedthrough the nozzle or jet 35.

Arranged at one side of the body of the carburetor is a small tank or receptacle ll adapted Iherefore, while in subsequent portions of the specification and in the claims the part 4| is referred to as a receptacle" it is to be understood that such word is used as including a separate tank as shown or a compartment or chamber formed in the main body of the carburetor or at any other convenient location.

Receptacle 4| is shown as a flat, generally rectangular device although the particular shape is not controlling. It includes a body portion 42 and a top or cover 43 secured in place as y screws. By means of a.v partition 45 the interior of the body 42 is divided into chambers 46 and 41 of which the latter is shown somewhat larger than the former. Threaded into the upper end of chamber is a plug 48 having metered orifice 49 therethrough. The upper surface of the plug is flush with the upper end of the body but the top 43 is hollow in its under side so that the chambers 46 and." are in communication through the orifice 49.

Receptacle body 42 is provided with an inlet entering the lower end portion of the chamber 46 and with an outlet 5| from the lower end portion of chamber 41. Into these openings are threaded elbows 52 and 53 respectively. On one face of the body 42 is a boss 54 having a thread-.

ed stud 55 projecting therefrom. A drilled hole 55 through the stud communicates with themterior of the body, entering the upper portion of chamber 41. If desired a metering plug 51 is threaded into the elbow 53 so as to be removable and replaceable should an orifice of a different size be desired.

The passage 29 communicates with a well 58 at the lower side of valve 30 and also communicating with the well, being secured by a fitting 59, is a tube 60. Such tube having its other end attached to the elbow 52 by a, fitting 5| places the'well in communication with the lower end portion of the chamber 45. Thus the chamber 45 is placed in communication with the float chamber 15 through the valve 30 and with the pump through the lateral passage 29.. When the piston 25 is in its upper position the pump is loaded with fuel drawn from the float chamber through the valve 30.

Thereafter on the suction or vacuum being reduced the spring 23 acts and the piston 20 descends to discharge the pump. At this time the valve 35 is closed and the pressure on the fuel forces valve 3!! closed and the fuel is discharged by the pump through the tube 50. Suflicient pressure to force open the valve 56 is not gen erated and such valve remains closed until the stem 31 is engaged by the piston 20 as in Fig. 3 when the valve is forced and held open until the piston is again moved upwardly to load the pump.

Heretofore in carburetors of the type shown the pump l8 discharged only through the nozzle 35. The arrangement was such that the pump was operated to loaded'position while there was suction in the engine equipped with the carburetorand then on reduction of the suction or vacuum as by opening of the throttle valve l4 the spring 23 of the pump would act to discharge it and the fuel would be forced through the nozzle 35.

With such an arrangement the pump would discharge the fuel through nozzle 35 when the engine ignition was cut off and the engine stopped and such discharged fuel would simply run into the intake manifold and then into the engine when not needed. Also if the engine was equipped with an air inlet valve as shown in my Patent 2,017,914 of October 22, 1935 the pump if in loaded position would discharge through nozzle 85 each time the valve opened at which times it is desirable that no fuel be fed to the engine. To overcome these difficulties and prevent waste of fuel I provide the receptacle 4| and the connections thereto so that at each discharge of the pump the fuel passes to the receptacleand is taken therefrom at such times as the fuel is required by and in accordance with the air entering the engine. That is the fuel is not squirted into the intake by the pump regardless of the air stream but is sucked into the carburetor and thence the engine in proportion to the air entering the engine.

A tube 62 communicates with the lower por tion of the chamber 41 being attached at one end to the elbow 53 by means of a fitting 63. Such tube is attached to a wall of the fuel passage 25 by a fitting 54 and extending through such fitting and wall has its other end projecting through the venturi l3 forming a nozzle 55.

The receptacle 4| is mounted on the carburetor by passing the stud 55 through a drilled hole in the carburetor wall so as to dispose an end of the stud in the upper portion of the float chamber l5. Then a nut 65 is threaded onto the stud to clamp a portion of the carburetor wall between the nut and the boss 54 whereby to secure the receptacle to the carburetor. Thereafter an opening 61 is drilled through the nut and into the drilled opening 55 through-the stud. Thus the-upper portion of the chamber 41 is placed in communication with the carburetor float chamber l5 above the float level.

Obviously fuel from the float chamber of the carburetor flows intothe receptacle chamber 46 until the level of fuel in chamber 45 is the same as that in chamber l5. Thereafter as additional fuel is forced into chamber 45 ondischarge of the pump it may flow through the orifice 49 and over the partition 45 into the chamber 41. Such fuel remains in chamber 41 while the engine throttle valve is closed or while the air inlet valve of my patent above referred to is open. Assuming such air valve to be closed or absent from the engine, on opening of the throttle valve while the engine is operating there is an increase in the suction or degree of vacuum in the Venturi of the carburetor and fuel is drawn from the chamber 41 through the tube 62 into the engine. As the engine operates under conditions causing a high degree of vacuum in the Venturi portion of the carburetor fuel'is drawn through the tube 52 until the supply in chamber 41 is exhausted but the engine cannot draw fuel from the chamber 45.

The capacity of the chamber 46 is such that as the pump is drawn to loaded position should the valve 30 not release the fuel as fast as the pump requires it the additional fuel will be taken from the chamber 45 to satisfy the requirements of the pump. That is during operation of the engine the chamber 46 remains full and its capacity nozzle 65 it may contain several discharges of the pump l8. p

Hole 61 has its upper end above the fuel level in the float chamber. Owing to the presence of this hole and the hole 56 which connects it to the interior of chamber 41, when the fuel is exhausted from such chamber, air is drawn through tube 6! from the source and in the manner 1 specified it will be clear that only air which has passed through an air cleaner will be fed into the engine as all air for the latter passes through a cleaner as it enters the carburetor. As the I upper end of the hole 61 is just under the dividchamber, a nozzle in the venturi, a pump communicating with said fuel chamber and including a vacuum operated means to move it to loaded position and spring means to operate it to discharge fuel on reduction of vacuum on said means, a receptacle, a passage connecting the discharge of the pump with the upper end portion of the receptacle whereby oneach discharge a of the pump fuel is delivered to the receptacle, said passage communicating with said fuel chamber whereby to maintain the fuel in the passage at ,the level of the fuel in the chamber, said passage below the level of fuel therein having a greater cubic capacity than said pump whereby V said pump in its movements to loaded position carburetor, means providing a passage at the cannot exhaust the fuel from said passage and hence is prevented from drawing air, and a passage connecting the lower end portion of the receptacle with said nozzle for the passage of fuel from the receptacle to an engine fed by the carburetor.

2. An attachment for a carburetor including a throttle, a fuel chamber, a fuel pump adapted to be operated to loaded position by vacuum, and

a spring means to operate the pump to discharged position, a receptacle at the outer side of said outer side of said carburetor and connected with said fuel chamber whereby the level of fuel in said passage is the same as that in the fuel chamber, said passage also connected with said receptacle and said pump whereby at each discharge of the pump fuel is forced through said passage into the receptacle, said passage below the level of fuel therein having a greater cubic capacity than said pump whereby said pump in its movements to loaded position cannot exhaust the fuel from the said passage and hence is prevented from drawing air, an outlet passage from the receptacle into the carburetor and through which'fuel is drawn into an engine fed by the carburetor on opening of said throttle while the engine is operating, a hollow bolt secured to.said receptacle and passing through a wall of the carburetor and securing the receptacle to the carburetor, and said hollow bolt providing a passage communicating the upper portion of said receptacle with the interior of the carburetor above the liquid level therein whereby to prevent setting up of a siphonic action through the receptacle and whereby to balance the air pressure in the receptacle and in the carburetor.

3. In a carburetor, a fuel pump adapted to be operated to charged position by vacuum and other means to operate the pump to cause it to discharge fuel, a receptacle of a capacity to contain several complete discharges of said pump, means connecting the receptacle with the carburetor for the passage of fuel therethrough from the receptacle to an engine fed by the carburetor, said connecting means and receptacle arranged and constructed whereby fuel is drawn into the engine from the receptacle only when the engine is exerting a suction pressure on the carburetor, and means providing a passage between the pump and receptacle whereby on reduction of vacuum on the pump all fuel discharged thereby is delivered to and retained by said receptacle whereby to prevent waste of fuel when the vacuum pump discharges and there is no suction on said carburetor and whereby to have such fuel available to the engine through said connecting means on reestablishment of suction in the carburetor,

said passage connected with the fuel chamber of

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