US2024419A - Carburetor - Google Patents

Description

Dec. 17, 1935.

' Filed sept.' 22, 195o CARBURETOR F. o. BALL 'ET AL VIZ'Shee's-Sheet l.

FREDER/C/f 0. BALL. ANDl IN VEN T 0R5 l i ATTORNEY Dec. 17, 1935.

F. O. BALL ET AL CARBURETOR Filed sept. 22, 1930 A FEEDER/CK O.

INVENToRs BALL, AND

By' THM M. BALL..

? www Patented Dec. 17, 1935 CARBURETOR Frederick o. Bau and Thomas M. Bau, u

Detroit, Mich.

Application September 22, 1930, Serial No. 483,533

9 Claims.

The main objects of the invention are to provide an improved carburetor of the raw gas feeding type in which some of the fuel supplied to the mixing chamber thereof during normal operation is fed directly from a fuel tank by a fuel pump while the remainder of the fuel supply l vide means for reducing the pressure to which the fuel is subjected by the fuel pump at the orifice which meters the flow for the idling mixture so as to allow employment of an orifice that is large enough to obviate clogging by fine particles of dirt or other foreign matter.

Further objects of the invention are to provide a variable valve for regulating the pressure to which the fuel that is fed directly to the mixing chamber by the pump is subjected so as to in turn` regulate the quantity ofthe direct fuel feed; to provide means for operating-the variable valve in timed relation with respect to the throttle of the carburetor so as to gradually increase the pump fed portion of the aggregate fuel discharge, preventing a radical decrease in the fuel ratio of the idling mixture as the throttle is opened from an idling position to the position at which the carburetor suction commences to feed fuel from the fuel reservoir to the mixing chamber; and to provide valve operating means of this kind which is adapted to gradually decrease the pump fed portion of the aggregate fuel discharge as the throttle is opened beyond the above position which is the suction feeding end of the idling range.

An illustrative embodiment of our invention is shown in the accompanying drawings, in which:

Fig. 1 is a vertical section of a carburetor embodying our invention.

Fig. 2 is a. side elevation of an ing our invention.

Fig. 3 is a diagram illustrating graphically the relation of the-percentage of fuel to the cubic feet of air supplied per minute by the various engine embodyfuel feeding factors involved in our improved carburetor. p

In the form shown, our improved carburetor I,

- is illustrated in connection with an internal combustion engine 2 having an intake manifold 3 which includes a riser 4 on which the carburetor I is mounted. Mounted on the side of the crank case of the engine 2 is a fuel puinp 5 which is adapted to be actuated by a cam on the cam shaft 6 of the engine. The fuel pump has an inlet l communicating through a pipe-8 with a gasoline tank 9 of conventional construcnon. 5

'I'he carburetor I includes a body part I 0 having a fuel mixture passage I I therethrough forming a mixing chamber in which fuel and air are mixed together. A shaft I2 journaled in the air inlet end of the carburetor carries a choke valve I3 of conventional construction and a similar shaft I4 journaled in the fuel mixture outlet end thereof carries a throttle valve I5, also of conventional construction, by which the flow of fuel mixture from the carburetor is regulated.

The body part l0 is provided with a fuel'reservoir I6 which has an inlet passage I'I communicating at one end with the interior of the reservoir and at its other end with a fuel inlet passage I8 which is connected by a pipe I9 with the pressure side, or outlet 20, of the fuel pump 5. Formed in the inner end of the passage Il of the reservoir is a valve seat ZI with which a valve 22 coacts for regulating the flow of fuel into the reservoir.. I'he valve 22 is carried by a valve stem -23 which is slidably mounted in an aperture 24 formed in a cover 25 on the top end of the reservoir.

The reservoir I6 is provided with conventional s fuel level regulating apparatus comprising a float 26 having an arm 21 on one end journaled at 28 on a bracket 29 carried by the cover 25., The outer extremity of the arm 21 has a pin 30 which extends between spaced collars 3| and 3IA rigidly mounted on the valve stem 23.1509. as to raise the valve 22 from its seat when the-'j' float 26 tilts downwardly due to a decrease in the j fuel level of the reservoir and to lower the valve 22 into engagement with the seat 2| when the 40 float 26 is lifted by the fuel to a predetermined elevation.

Formed in the body part I0 is a fuel passage 32 which communicates at its upper end with the interior of the reservoir I6 and at its lower 45 end with a fuel passage 33 which extends upwardly at an inclination to the axis of the fuel mixture passage II, communicating with a fuel passage 34 which is formed in a collar 35, concentrically mounted in the fuel mixture passage 50 I I. A restrictionG, having an economy metering orifice therein, is provided in the outlet passage 32 of the reservoir. p

'I'he collar 35 hasv a transverse rib or bridge 31 on which a downwardly extending discharge 5g 'fio nozzle 38 is formed, the latter being located centrally of the fuel mixture passage I I and having an air inlet aperture 38. The carburetor I is provided with a snatcher which includes a passage 39 extending through the left extremity of the bridge 31 and communicating with a passage 40 formed in the left side wall of the mixing chamber as shown in Fig. 1, the lower end of the passage 40 having an outlet 4I communicating with the fuel mixture passage I I on the leeward side of the throttle valve I4.

Mounted in the lower end of the inlet passage 33 of the body part I 0 is a nozzle member 42 which communicates through a passage 43 with the fuel passage I8 to which fuel under pressure is supplied by the pump. The nozzle 42 forms a seal between the outlet passage 32 of the reservoir I6 and the fuel pressure passage I8 and has a metering orifice 44 through which fuel under pressure is discharged into the inlet passage 33 independently of the fuel which flows thereinto "from the reservoir I6. The supply of fuel which passes through the orice 44 provides an idling mixture which is fed to the cylinders of the engine through the snatcher when the throttle valve I5 is relatively closed and also augments the supply of fuel which is fed directly from the reservoir to the mixing chamber of the carburetor by the normal suction therein when the throttle I5 is in a relatively open position.

In order to obviate the necessity of using an excessively small metering orifice 44 for the idling fuel supply, apparatus is provided for regulating the pressure in the passages 43 under which fuel is fed to the nozzle 42. This apparatus includes a by-pass which communicates with the low pressure side or inlet 1 of Athe, fuel pump 5 through a pipe 45. The by-pass also includes passages 46 and 41 formed in the body part I0 of the carburetor and communicating with the fuel pressure passage I8. A valve seat 48 is formed at the upper end of the passage 41 for receiving a pressure regulating valve 49, the stem 50 of which is slidably mounted in the passage 41 and normally urged towards an open position by a spring 5I which bears against a shoulder 52 on the Ybody part I0 and a head 53 on the outer extremity of the valve stem 50.

Formed on the body part I0 of the carburetor is a bracket 54 on which a rocker arm 55 is pivotally mounted at 56. The right end of the vrocker arm 55 carries an adjustment screw 51 which bears against the head 53 of the valve stem 50 and the left end of the rocker arm is pivotally attached at 58 to one end of a link 80, the other end of the link 80 being pivoted at 5I to a crank arm'82 which is carried by the shaft I4 of the throttle valve. l

In operation, the. pump 5 supplies fuel under pressure both to tizi-fv interior of the reservoir and to the idle metering orifice 44. Some of the fuel which is supplied to the carburetor under pressure is by-passed back to the low pressure side of the pump through the pipe 45 under control of the valve 49 and the orifice, thereby reducing the rate of flow of fuel through the orifice. During idling operation of the engine a comparatively small flow of liquid fuel is needed. This requirement would necessitate the use of an extremely small metering orifice 44 in order to cut down the quantity of fuel supplied to the engineif when the throttle valve I5 is comparatively closed or in the positionthereof which corresponds to the idling stage of the engine thus permitting some of the fuel to flow back into the low pressure side of the pump and reducing 5 the pressure of the fuel passing through the metering orifice 44 and correspondingly reducing the rate of flow of fuel therethrough.

The valve actuating mechanism by which the pressure regulating valve 49 is operated in timed relation with respect to the throttle valve l5 is adapted to close the pressure regulating valve 49 when the valve I5 is in that position at which the velocity of the gas in the fuel mixture outlet creates a suction which is suillcient to commence the feeding of fuel from the reservoir I8., and to gradually open the valve 49 thereafter as the throttle valve l5 is rotated to a further open position.

The effect of the coordinated action between 9 the throttle valve and the pressure regulating valve is illustrated in Fig. 3 in which the curve AAA, called the normal idle curve, represents the mixture ratio which results from the feeding of fuel solely through the metering orifice 44 under a pressure corresponding to the pressure existing -in the system when the valve 49 is in the position shown in Fig. 1 during an increasing supply of air. The curve BB represents the fuel ratio which s is produced by feeding fuel solely from the nozzle by the normal carburetor vacuum during an increasing supply of air to the fuel mixture passage. The curve ADE represents the sum of the fuel ratios resulting from simultaneously feeding fuel under the conditions of curves AAA and BB. The curve CCC, called the rich idle curve. is similar to the curve AAA and represents the fuel mixtures which are produced by feeding fuel to the fuel mixture passage solely through the metering orifice 44 when the pressure regulating valve 49 is fully closed so ,as to subject the fuel to the full pressure of the pump. The curve CFG corresponds to the curve ADE and is the sum of gil; fuel mixtures represented by curves CCC and As the throttle I5 is opened from its comparatively closed or full idling position shown in Fig. 1, the valve operating apparatus connectedwith the throttle gradually closes the pressure regulating valve 49 causing the fuel ratio to change from the pointv A on the normal idle curve AAA towards a point F on the rich idle curve CCC, at which point, the pressure regulating valve 4l is fully closed and the feeding of fuel by the 5 suction of the carburetor commences.` Upon fur.- ther opening of the throttle the mixture ratio is affected both by the suction fed supply of fuel and by the pressure fed supply of fuel. If the pressure in the system were allowed to remain (56 constant at the full capacity of the pump, the mixture ratio would follow the curve FG causing an abrupt change at the point F. However, as the throttle is opened from the suction feeding end of its idling range, the valve actuating mecli- 6'5" anism gradually opens the pressure regulating valve 49 causing the fuel ratio to follow the curve FH which gradually blends into the curve AF, thereby avoiding abrupt and radical changes in the fuel ratio at the stage wherein fuel commences to be fed by suction.

Although but one speciilc'embodiment of this invention has herein been shown and described. (it will be understood that various changes including the size, shape and arrangement of parts may 7i' be made without departing from the spirit of our invention and it is not our intention to limit its scope other than by the terms of the appended claims.

We claim: v l

1. An internal combustion engine fuel system including a carburetor having a fuel mixture passage and a communicating fuel reservoir for feeding fuel thereto by the suction in said passage, a throttle valve in said passage, a fuel inlet communicating with said passage, means for discharging fuel under pressure through said inlet, and pressure regulating apparatus operatively connected with said throttle and adapted to increase the discharge pressure in said inlet as said throttle is opened from its idling position to the position thereof at which fuel commences to be fed from said reservoir by the suction in said passage, and to decrease said discharge pressure during further opening movement of said throttle.

2. An internal combustion engine fuel system including a carburetor having a fuel mixture passage and a communicating fuel reservoir for feeding fuel thereto by the suction in said passage, a throttle valve in said passage, a fuel inlet communicating with said passage, means for discharging fuel under pressure through saidinlet, pressure regulating vapparatus operatively connected with said throttle and adapted to increase the pressure in said inlet to a maximum when said throttle isA moved toward a predetermined position and to decrease said pressure as said throttle is moved beyond said predetermined position, and means for adjusting said pressure regulating apparatus for vvarying thev position of said throttle at which the maximum pressure is maintained.

3. An internal combustion engine fuel system including a carburetor having a fuel mixture passage, a throttle valve in said passage, a fuel inlet communicating `with said passage, means for supplying fuel under pressure to said inlet, a by-pass communicating with said means on the low and high pressure sides thereof respectively, a variable valve in said by-pass, and valve actuating mechanism connected with said throttle for regulating the pressure under which fuel is fed to said inlet and adapted to produce a maximum pressure when said throttle is in a predetermined position between its open and closed positions and to produce a low pressure when said throttle is either opened or closed from said predetermined position. A

4. An internal combustion engine fuel system including a carburetor having a fuel mixture passage and a communicating fuel reservoir for feeding fuel thereto by the suction in said passage, a throttle valve in said passage, a fuel inlet communicating with said passage on the Windward side of said throttle valve, a snatcher communicating with said inlet and communicating with saidl vpassage on the leeward side of said throttle, and a pump for supplying fuel under pressure to said reservoir and inlet so as to provide an idling A fuel mixture when the suction in said passage isinsuicient to feed fuel from said reservoir.

5. An internal combustion engine fuel system including a carburetor having a fuel mixture passage provided with an air inlet, having a fuel reservoir, a throttle valve in said passage, a

fuel inlet communicating with said passage between said'air inlet and said throttle valve, an idling by-pass passage'communicating with said fuel mixture passage on the opposite side of said 5 throttle valve and means independent of said reservoir for supplying fuel under pressure to said idling by-pass soas to produce an idling fuel mixture when said throttle valve is closed.

6. A fuel system for an internal combustion 1,0 engine comprising an engine fuel mixture inlet and a fuel supply having an outlet communicating with said inlet for feeding fuel to the latter by suction, means independent of said outlet for continuously supplying fuel under pressure directl5 ly to the, fuel inlet and to said fuel supply, a. member having an orice for metering the pressure fuel feed to said inlet, and means for varying the pressure by which fuel is fed through said metering orifice comprising a by-pass com- 20 municating at its opposite ends with the low and high pressure sides of said first mentioned means, respectively, and having a variable valve therein.

. '7. A fuel system for an internal combustion engine comprising an engine fuel mixture inlet 25 and a fuel supply therefor having an outlet communicating directly with said fuel inlet for feeding fuel thereto by suction, a pump for continuously supplying fuel under pressure to said fuel inlet and to said fu'el supply, a member having 30 an orifice for metering the pressure fuel feed to said inlet independently of the fuel fed thereto by suction, and means for, varying the pressure by which fuel is fed to said metering orifice comprising a by-pass communicating at .its opposite 35 ends with the low and high pressure sides of said pump, respectively, and having a variable valve therein.

8. An internal combustion engine fuel system including acarburetor having a fuel mixture pas- 40 sage, means including a throttle valve in said passage and normal throttle actuating apparatus for controlling the flow of fuel mixture through said passage, a fuel inlet communicating with said passage, means for discharging fuel under pres- 45 sure through said inlet, and pressure regulating apparatus operableby and in consonance with said throttle actuating apparatus and adapted to increase the pressure of the fuel discharge through said inlet when said throttle is moved in one 50 direction toward said predetermined position, and to decrease said pressure when said throttle valve is moved in the same direction beyond said predetermined position.

9. A fuel system for an internal combustion 55 engine including an engine fuel mixture inlet and a fuel supply therefor, means for continuously supplying fuel under pressure directly to said fuel mixture inlet and to said fuel supply, means including a normally stationary member having a 60 fixed orifice for metering the pressure fuel feed to said inlet, and variable means independent of said member providing a controlled escapement of fuel after the latter has passed said orifice for varying the pressure by which fuel is 05 fed through said metering orifice while the effective size of said orifice is maintained fixed.

FREDERICK O. BALL. THOMAS M. BALL.

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