US2145672A - Carburetor - Google Patents

Description

s. M. UDALE CARBURETOR Filed May 25, 193% 5 Sheets-Sheet l E L A D U M S.

GARBUREfIOR Filed May 25, 1936 3 Sheets-Sheet 2 5. M. UDALE CARBURETOR Filed May 25, 1936 3 Sheets-Sheet 3 INVENTOR Watenie lien. 3i, 193$ STATES P Wgj if UARBURETOR troit, Mich, a trust Application May 25, 1936, Serial No. 81,551

14 Claims.

The object of this invention is to improve the acceleration obtained with air valve carburetlon and specifically with self-feeding carburetors. The self-feeding carburetors for which this invention was made are those. in which the air valve is located in the main air entrance and this air valve creates a depression in a small venturi leading to the mixing chamber and also in a second small venturi, the throat of which is connected to the float chamber at a point above the level therein. The throat of the first venturi is connected to the fuel in the float chamber below the level therein, a difierential pressure is thereby created so that fuel is drawn into the float chamber and fuel is' drawn out of the float chamber into the mixing chamber because of the higher depression in the throat of the first venturi. On opening the throttle in the mixture outlet suddenly, the air valve opens slowly because of the dash pot which lid is connected to it to prevent fluttering.

This invention provides means whereby opening the throttle automatically increases the rate of opening the air valve by operating an air compressor by the action of the throttle valve and ilt using the compressed air to open the air valve. At the same time the vacuum in the float chamber is temporarily released by means of the compressed air. The engine is thus enabled to draw more than its usual supply of air and as the pressure in the float chamber rises or rather as the depression in the float chamber is temporarily reduced the flow of fuel is increased proportion ately to the flow of air, which is also increased by the increased opening of the air valve. An adlid lit ditional object is to improve the hill climbing ability of the car.

Figure 1 shows a cross-sectional elevation taken in plane l--| of Figure 2.

Figure 2 shows a plane view of the carburetor shown in Fig. 1.

Figure 3 shows a cross-sectional elevation taken on plane 3-3 of Figure 2.

Figure 4 shows a side view in elevation looking in the same direction as Figure 1.

Figure 5 shows an alternative construction.

Figures 6, 7 and 8 show an alternative construction in which an additional weight is moved by the air valve to increase the lift on a hill without increasing the resistance to open the valve when running on the level.

Figure 8 corresponds to Figure l with the addi tional weight added.

Figure 6 corresponds to Figure 4 with the addltional weight added.

In the figures, i is the air entrance, ii is the Wilt air valve therein, i2 is one of the two similar mix ing'chambers which'derive their air supply from the air entrance ill. it is an air bypass leading to the two small venturis it, which discharge a rich mixture into each of the two mixing chambers it below the air valve l l. The fuel is derived from a floatchamber it through a restriction l' c controlled by a needle valve l6. ii is an accel erating fuel pump which also obtains its fuel supply from the float chamber it, but this particular lo .fuel pump forms no part of this invention. A horizontal bar it operates a piston l9, the spring being interposed between the piston is and the bar it. A rod 2i. is connected to the bar it, which bar also connects to the needle valve it so 15 that when the rod 2! is moved up the piston it pushes fuel out of the pump l'l into the mixing chamber and the needle valve it admits fuel past the restriction l5 into the small venturl it. The depression or suction in the float chamber M is all created by the second' small venturi 22 shown in. Figure 3.

In Figure l, 23 is the mixture outlet, the flow through which is controlled by the two throttle valves 2B. The throttle valves 2t-2t are con- $5 ,1

nected through a link 25 (Fig. i) to the shaft 26 which is firmly connected to the lever 271 which is connected to the rod 25 so that on opening the throttles 2t-2t, the ,rod 2! (Fig. l) is raised and fuel is discharged through the pump ll through a so passage 5 and nozzle it and fuel is also admitted through the opening it to the venturi [It and so into the mixing chamber it. A second link it is connected to the throttle 2t and this link connects to a piston 29 which reciprocates in an in as clined cylinder til. These elements constitute one of the principal features of my invention. Any air compressed in 3% when the throttle it is open-- ed suddenly discharges through a passage ii into. a chamber 32 provided with a diaphragm 33 dd which carries an adjustable needle valve M which admits air to an air passage 35 which discharges air into the upper part of a float chamber at and thereby reduces the vacuum in the float chamber.

As a convenient method of modifying the action, M a small air bleed may be provided in 30. Connected to the air valve ii is a dash pot is which slides in a cylinder ti. This dash pot is connected through the pin 38 to the weight 39 which constitutes the load for the air valve l (I, both the all air valve ii and the weight 39 being mounted on the shaft it. This shaft it also controls the movement of the lift needle ll which is connected to the piston 36 which controls the flow through the small second venturi 22 (Fig. 3). Sid

In Figure 3, a passage 55 leads on from the air entrance Ill to a chamber 54 which is the air entrance to the small Venturi 22, a longitudinal passage 53 leads this air to the restriction 56 controlled by the needle 4|, the air flowing to the mixture chambers |2|2 through th passages 42 and 43 (Fig. 2). The passage 3| continues on past the chamber 32 and discharges air into the lower part of the cylinder 31 on the underside of the piston 36 (Fig. 1).

In Figure 5, an air passage 5'! connects the left hand side of the piston 59 with the mixture outlet 23. A spring 58 operates the piston 59 in the cylinder 30. A restricted opening 50 is provided in the end of the cylinder 30 and this is controlled by a valve 5| mounted on a spring 52 (which may be made of bimetallic material) riveted to the end of the cylinder 30.

In Figures 6 and 8, the same parts are numbered with the same numbers as Figures 1, 2 and 3. An additional weight 64 is shown suspended from the shaft 40 and thereby connected to the air valve by means of the arm 63 which is pivoted to the weight 64 at the pivot 65. An additional pivot 66 in the weight 64 is connected to a link 61 which is hinged to a bracket 69, which projects from the body of the carburetor. In Figure 6, the linkage 63, 64, 65, 66, 61 and 68 is shown in the various positions corresponding to the various positions of the air valve namely closed, half open, wide open. This is the wellknown James Watt straight line motion and is the equivalent of the horizontal piston ll shown in Figure '7, which is moved by the spherical end 10 located on the end of the lever 63. The piston 1| moves in the cylinder 12, the walls I3 of which are integral with the carburetor body. Obviously, the cylinder 12 can be arranged to function as a dash pot in the same manner as the dash pot 31 cooperates with the air pump 30 and the weight 39, but this would be merely a repetition of the disclosure already made.

Operation As this invention relates only to the parts 29, 30, 3|, 32, 33, 34, 35, 36, 31, 50, 5|, 52, 51, 58, 59, 63, 64,65, 66, 61, 68, 69, 10, II, 12, 13, I4, it is not necessary to discuss the well-known operation of the other parts of the carburetor.

During acceleration when the throttle 24 is opened suddenly, the piston 29 compresses air in the cylinder 30, air flows up the passage 3| into the chamber 32, pushes the diaphragm 33 over to the right in Figure l and to the left in Figure 8, unseats the valve 34, and a minute portion of air flows through the passage 35 into the float chamber 44. The amount of air which flows is then determined by the taper on the needle 34, the adjustment of the needle 34 and the stiffness of the diaphragm 33 and the size of the relief opening 50. At the same time, air is admitted to the underside of the piston 36. The effect of the weight 39 is thereby counteracted by the upward pressure of the air under the piston 36. Obviously, the air valve |l opens more quickly than would otherwise be the case. It is equally obvious that the flow of gasoline through the restriction 5 is greater by reason of the air flowing through the pipe 35 than otherwise would be the case.

In order to start the engine during hot weather, a thermostat 94 (see Figure 3) is provided located in the bypass 45 which communicates with one of the mixture outlets 23 through the opening 46. A valve 41 is provided mounted on the pin 48 for the right.

controlling the flow of air from 45 past the valve 41 to the outlet 46. The valve 41 is seated by two forces, namely, by theeffect of heat on the thermostat 94 and also by the effect of air flow past the valve 41. This particular detail is not part of this invention and will, therefore, not be discussed exhaustively.

In Figure 5, the vacuum in the mixture outlet 23 draws the piston 59 over to the left compressing the spring 58'. On opening the throttle suddenly, the spring 58 moves the piston 59 over to Compressed air then flows up 3|. In Figure 5, a check valve 5| is added to control the air entrancelthrough the restricted opening 50 and to check the air exit through the same opening 50. This check valve is mounted on the flexible flat spring 52 which may be of bimetallic material. Hence, during acceleration the opening 50 is closed by the valve 5|, but during deceleration air is drawn back into 30 through 50. Hence, closing the throttle will not unduly disturb the air valve In very hot weather if the spring 52 is made of bimetallic material, this fact will render this accelerating means less effective and thus more effective in very cold weather.

In the operation corresponding to carburetor illustrated in Figure '7, on accelerating the engine, the weight 1| tends to hold the valve closed. but as described above, the air compressor 3|! corrects this tendency.

On the other hand, when climbing a hill, the w ight 1| tends to hold the air valve closed. The t dency of the pivoted weight 39 to increase the lift on the hill, as described in the Patent No. 2,080,570, issued May 18, 1937, to George M. Holley, is increased. The lift on a hill is thus increased not only when the engine is idling, but also when the air valve is wide open. It is quite obvious that with the construction shown in Figures 6 and 8, the air valve resistance of the weight 39 to the opening of the air valve is actually less on a hill when the air valve is wide open than it is when running on the level. This defect is corrected by the addition of the weight 64, which moves parallel to and in the direction of motion of the automobile. The combination of a weight moving from an angle of say 30 idle to say wide open with a weight which moves forward in a straight line gives an improved result when climbing a hill.

The invention consists of modifying the action of a weighted air valve by means of a weight moving in a straight line and also by means of an air compressor operated by the throttle.

The larger weights 39 oscillate in a chamber located on the engine side of the air valve N. This chamber is in free communication with the mixing chamber. The weights 39 are thus completely enclosed. In the case of Figure 7, the

horizontal sliding weight H is also enclosed.

Wherever a weight, such as 64 in Figures 6 and 8 is permitted to oscillate in the open air, objections are raised on many grounds.

What I claim is:

1. A fuel lift carburetor for motor vehicles having an air entrance, an automatic air valve therein responsive to. air flow therethrough. a mixing chamber, a mixture outlet therefor, a throttle valve therein, a Venturi passage through which air is bypassed into said mixing chamber around said air valve, a fuel supply chamber, a fuel passage leading therefrom discharging into the throat of said Venturi passage, a second Venturi passage through which air is also bypassed around said air valve into said mixing chamber,

a passage connecting the throat of said second venturi with the upper part of said fuel supply chamber so as to create a vacuum therein, means for increasing this vacuum when a vehicle is ascending a hill. comprising a weight attached to said air valve and adapted to be moved by said air valve in a straight line in a plane parallel to and in the direction of the motion of the vehicle.

2. A fuel lift carburetor for motor vehicles hav ing an air entrance, an automatic valve therein responsive to air flow therethrough, a mixing chamber, a mixture outlet therefrom, a throttle .valve therein, a Venturi passage through which air is bypassed into said mixing chamber around said air valve, a fuel supply chamber, a fuel passage leading therefrom discharging into the throat of said Venturi passage, a second Venturi passage through which air is also bypassed around said air valve into said mixing chamher, a passage connecting the throat of said venturi with the upper part of said fuel supply chamber so as to create a vacuum therein, means for increasing this vacuum .when a vehicle is ascending a hill, comprising a weight attached to said air valve and adapted to move in a straight line parallel to the motion of the vehicle and in the direction of motion of the vehicle, means for opposing the increased vacuum produced by the inertia effect of said weight during acceleration comprising an air compressor adapted to be operated by the throttle, a passage leading from said air compressor to the upper part of said fuel supply chamber and a pressure responsive valve in said passage.

3. A fuel lift carburetor as set forth in claim 2 including an air dash pot connected to said weight, means for admitting compressed air from said air compressor to said dash pot for the purpose described.

4. A fuel lift carburetor as set forth in claim 1 including means for opposing the inertia effect of said weight during acceleration comprising an air compressor adapted to be operated by the throttle, an air dash pot connected to said weight, means for admitting compressed air from said air compressor to said dash pot for the purpose described.

5. In a fuel lift carburetor having a main air entrance, an air valve mounted therein responsive to air flow therethrcugh, yieldable means for closing the air valve, a mixing chamber, a fuel supply chamber, a fuel passage leading therefrom and discharging into said mixing chamber, a passage connecting said mixing chamber to the upper portion of said fuel supply chamber to maintain a substantially uniform depression therein. a mixture outlet from said mixing chamber, a throttle valve therein, an air compressor connected to said throttle, a passage leading from said air compressor to said fuel supply chamber, an-automatic pressure responsive valve therein for admitting a limited amount of air to said fuel supply chamber, a compressed air responsive means connected to said air valve, a passage from said air compressor to said means whereby said air valve is opened by the air in said air compressor.

6. In a fuel lift carburetor having a main air entrance, an air valve mounted therein responsive to air flow therethrough, yieldable means for closing the air valve, an air dash pot for controlling said air valve, a mixing chamber, a fuel supply chamber, a fuelpassage leading therefrom and discharging into said mixing chamber. a mixture outlet from said mixing chamber. a throttle valve therein, an air compressor connected to said throttle, a passage from said air compressor to said air dash pot whereby said air valve is opened by the air from said air compressor, a second passage leading from said air compressor to said fuel supply chamber, and a valve in said passage adapted to be operated by air pressure.

7. A carburetor having a mixture outlet, 21. throttle valve therein, an air entrance, an automatic air valve therein, responsive to air flow therethrough, an air dash pot connected to said air-valve, a mixing chamber, a fuel nozzle discharging therein, means responsive to a sudden opening of the throttle for injecting an additional shot of fuel into said mixing chamber, an air compressor,- means for operating said air compressor responsive to the opening of said throttle, a passage leading from said compressor, to said air dash pot whereby opening the 'throt-- tle, automatically opens the air valve.

' 8. The carburetor as set forth in claim 7 in which the air compressor consists of a cylinder,

a piston therein, a passage connecting one end a,

of the cylinder to the mixture outlet and a spring connected to said piston whereby the suction in the mixture outlet moves th'episton in one direction and the spring moves the piston in the other, to compress air in the cylinder for the purpose described.

9. The carburetor as set forth in claim .7 in which the air compressor consists of a cylinder, a piston therein, adapted to compress air in one end of the cylinder, a restricted air vent in said end communicating with the atmosphere.

10. The carburetor as set forth in claim 7 in which the air compressor consists of a cylinder, a piston therein, adapted to compress air in one end. of the cylinder, a restricted air passage in said end communicating with the atmosphere, a check valve in said passage restricting the escape of air through said passage, a bimetallic spring hit controlling said check valve for the purpose described, 1

11. The carburetor as set forth in claim '7 in which the air compressor consists of a cylinder, a piston therein, adapted to compress air in one end of the cylinder, a restricted air passage in said end communicating with the atmosphere, a check valve in said passage, bimetallic spring means for opening said valve when the carburetor is hot, said valve being yieldably closed when the carburetor is cold.

12. A fuel lift carburetor as set forth in claim 1 in which a swinging weight is attached to the air valve so as to swing forward in the direction of motion under the influence of the opening motion of said air valve.

13. A fuel lift carburetor for motor vehicles having an air entrance, an automatic valve therein responsive to air flow therethrough, a mixing chamber, a mixture outlet therefrom, a throttle valve therein, a fuel supply chamber, a fuel passage leading therefrom discharging into the throat of a Venturi passage through which air is bypassed into said mixing chamber around said air valve, a second Venturi passage through which air is also bypassed around said air valve into said mixing chamber, a passage connecting the throat of said second venturi with the upper part of said fuel supply chamber so as to create a vacuum therein, means for increasing this vacuum when a vehicle is ascending a hill, com prising a weight attached to said air valve and Will 14. In a. fuel lift carburetor as described in claim 13 in which there is an air dash pot piston connected to said automatic air valve and a passage connecting said air compressor with said dash pot.

STANLEY M. UDALE.

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