US2499554A

US2499554A - Charge forming device

Info

Publication number: US2499554A
Application number: US558589A
Authority: US
Inventors: Emil O Wirth
Original assignee: Bendix Aviation Corp
Current assignee: Bendix Aviation Corp
Priority date: 1944-10-13
Filing date: 1944-10-13
Publication date: 1950-03-07
Anticipated expiration: 1967-03-07

Description

E o. wlR

CHARGE FORMI DEVICE Filed 0 1944 March 7,

rrow Patented Mar. 7, 1950 CHARGE FORMING DEVICE Emil 0. Wirth, South Bend, Ind., assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application October 13 6 Claims. 1

This invention relates to fuel systems for internal combustion engines and the like and more particularly to pressure fuel systems wherein the fuel is delivered to the carburetor or engine under superatmospheric pressure.

In present pressure fuel systems it is known to have the fuel delivered to the carburetor, chargeforming device or the like under predetermined, substant ally constant superatmospheric pressure by a constant delivery type of fuel pump, there being means for variably controlling the delivery of the fuel into the induction passage of-the :arburetor to meet the various requirements of the engine in accordance with one or more engine variables or in accordance with various operating conditions of the engine, which means is generally so constructed and arranged that the proportions of fuel to air of the fuel mixture is normallv maintained at a-substantially constant ratio. Inasmuch as it is desirable to vary the fuel to air ratio under various engine operating conditions to meet the requirements of the engine under said conditions it is an important object of the present invention to provide a pressure fuel system wherein the fuel to air ratio of the fuel mixture may be so varied.

Another object of the invention is to provide a device of this character wherein the fuel mixture ratio is controlled in accordance with various pressures in the carburetor induct on passage.

Still anot er objectof the present invention is to provide a fuel system of this character of simple construction and having improved performance and economy.

The characteristics and advantages of the invention are further sufficiently referred to in connection with the following detailed description of the accompanying drawing which represents a preferred embodiment thereof. After considering this example, skilled persons will understand that many variations may be made without departing from the principles disclosed,

and I contemplate the employment of any structures, arrangements, or modes of operation t at are properly within the scope of the appended claims.

In the drawing:

Figure 1 is a diagrammatical view of a fuel system embodying the present invention, parts of said system being in section; and

Figure 2 is a section taken on line 2-2 of Figure 1.

While the present invention is shown and described in connection with a downdraft carbu- 1944, Serial No. 558,589

the induction passage for controlling the flow of fuel to said passage, it is to be understood that the present invention may be used in other types fuel systems including those having other types of metering means, which means may include diaphragms or the like for controlling the metering of the fuel. In connection with the carburetor it may alternately be of the updraft or horizontal delivery type as well as of the downdraft type.

Fuel system generally The fuel system as shown in Figure 1 comprises the usual fuel tank l0, connected by a conduit i2 to a fuel pump H of known construction. The pump may be of the diaphragm type commonly used on present day automobiles, but for simplicity is shown as a gear pump having a by-pass l6 controlled by a pressure responsive valve l8, set for a predetermined pressure. Whatever the type of pump, it should provide fuel at a substantially constant pressure and should preferably prevent flow through the line when the engine is not operating. An outlet line 20 leads from the pump to a pressure regulator, indicated generally at 22, and a conduit 24 leads from said regulator to a separating chamber (not shown) in the upper portion of which a return line 28 conveys excess fuel, together with any vapor which may be present in the line, back to the tank Ill. The return line 26 is preferably provided, at its point of connection with the separating chamber, with a restriction (not shown) of such size as to permit pressure to be built up in the chamber. At the outlet of the separating chamber is a filter (not shown) preferablv of the type formed of a cylindrical stack of disks, generally known as anedge type filter, and wherein the fuel flows radially inwardly through apertures at the edges of the disks to an axial outlet passage; and thence, in the il ustrated embodiment, to a fuel discharge nozzle 28, of the carburetor indicated generally at 30. and the discharge of fuel from said nozzle 28 into the induction passage is controlled by a valve 3'! controlled through means, including a lever 34, in accordance with certain engine operating conditions, which means, shown herein and described hereinafter, comprises means responsive to fluid flow through the induction passage of the carburetor. This fluid flow responsive means is adapted to so control the flow of fuel into the induction passage as to proportion said fuel in accordance with the mass air flow through said retor having a movable flow responsive member in 55 induction passage and during normal cruising 3 operation of the engine said fuel to air ratio remains substantially constant.

The carburetor generally ly urges the vane in the closing direction. Fuel is discharged into the induction passage from the fuel nozzle 28 and the flow of said fuel is controlled by the valve 32 which is connected with and controlled by said vane, the connection between said valve and vane comprising a cam 44 secured to the vane and operably engaging a roller 48 mounted on the lever 34 which has an end 48 adapted to engage the stem 50 of said fuel valve 32. The valve 32 is adapted to be moved in the opening direction by said lever and is urged in the closing direction by a spring 52, it being noted that the pressure of fuel on the valve has little or no effect on the action of said valve, that is, the valve 32 is operable substantially independent of fuel pressure thereon.

' Fuel regulator Suitable means for regulating or controlling the pressure of the fuel posterior to the fuel pump and delivered to the carburetor induction passage is provided, and an illustrative example of one such means is shown in Figures 1 and 2 and comprises a body having a central casing member 64 which includes an inlet 65 connected with the conduit from the fuel pump 14, and an outlet connected with conduit 24 to the carburetor. A hollow end member 61 is secured to one side of the central member 64 by any suitable means such as screws 68, and a second hollow member 10 is secured to the opposite side of the central member 64 by screws I2. A flexible diaphragm 14 is secured between the casing members HI and 64 thereby separating the interior of the regulator into two chambers, 16 and 13. The former chamber is a fuel chamber and the fuel pressure therein urges the diaphragm downwardly, as viewed in Figures 1 and 2, and the latter chamber is subjected to variable fluid pressures as will be herematter more fully described. Within the chamber 16 there is a valve, indicated generally at 80, which is connected with the inlet 65 by a conduit 8|. The valve includes a seat 82 adapted to be engaged by a movable valve member which comprises a body member 84 having a recess in which a gasket 85 is secured by the overturning at 38 of the edges of said body member 84. The gasket 86 is preferably of some resilient material which is resistant to gasoline or the like, such as neoprene, although it may be of other material having the requisite qualities. The movable valve member is provided with an annular extension or boss 90 coaxial with the valve seat but of substantially smaller diameter than said seat and there is a stem 92 extending from the boss 90 but of smaller diameter than the latter. The movable valve member is connected to the diaphragm 14 by means of a yoke 94, best shown in Figure 2. which extends about the sides of the valve and which includes a portion 96, generally parallel with the diaphragm, and having an orifice therein which slidably receives the 4 stem 22 of said movable valve member. A spring 38, reacting between a head I and the member at of the yoke, urges the boss 20 andmember .3 together. The yoke is attached to the diaphragm by means of a rivet I02, there being a washer I" adjacent the side of the diaphragm opposite the yoke and secured by said rivet. The washer serves to reinforce and strengthen the central portion of said diaphragm in conjunction with that portion of the yoke abutting against the other side of the diaphragm and it is to be noted that the peripheral edge portion of the washer I" is turned away from the diaphragm so as to be slightly cup shaped.

It should be noted here that the valve seat is of relatively large diameter and is engaged by the resilient disk 30, and that the arrangement of the yoke 94 and the movable valve member, including the boss 90, is substantially coaxial with the valve and that said boss is of substantially smaller diameter than the valve seat. With this arrangement should the yoke become tilted slightly, due to the flexibility of the diaphragm which supports same, it will still exert a valve closing pressure on the boss 90 which pressure is within the cylindrical plane of the valve seat and will eifect a substantially uniform pressure of the resilient disk" on the valve seat 82 and will therefore effect positive closing of the valve. The spring 98 is adapted to retain the movable valve member in position with respect to the yoke but permits the above noted tilting thereof.

The casing member Ill has a hollow extension H0, shown as cylindrical in form and substantially coaxial with the chamber 16, and has the interior thereof in open communication with and forming a part of the chamber 18. The diaphragm is urged upwardly, as viewed in Figures 1 and 2, in opposition to the fuel pressure, by a spring H2 one end of which is received in the cup-shaped washer I33 and the other end of which is received on a spring retainer H4.

7 'Means for manually adjusting or varying the tension or force of spring H2 is provided and. as shown, includes an adjusting screw H8 screwed into an end wall I20 of the extension H0,

said screw being shown integral with the spring retainer H4 and adapted to be held in adjusted positions by a lock nut I 22.

While the regulator is shown as a separate unit it is to be understood that, if desired, it may be built into the carburetor.

Fuel under substantially constant pump pressure, entering the regulator by way of the inlet 65, passes through valve and into the chamber 16 and urges the diaphragm downwardly, as shown in Figures 1 and 2, in opposition to the force of spring H2 and the pressure of air in chamber 18 on said diaphragm, so that the valve 80 is controlled primarily by pressures on opposite sides of the diaphragm and by varying one of said pressures the pressure of fuel to the carburetor is varied. It is to be understood that as the effective closing force on valve 80 increases the pressure of fuel posterior to the regulator drops and vice versa.

Regulator control means As shown and described herein the effective force urging valve 30 closed is regulated or con- .trolled by varying the fluid or air pressure in the chamber 18 which in turn is controlled in accordance with various pressures within the induction passage of the carburetor. More speciflcally the air pressure in chamber I3 is the differential between the induction passage pressures posterior and anterior respectively of the throttle valve and/or vane 40. A conduit I30 is connected at one end of chamber I8 and at the other end with the induction passage posterior to the throttle. There is also a conduit I32 connected at one end to said chamber I8 and at the other end with a passage I34 having an opening into the air entrance portion of the induction passage and, as shown, said opening faces the air stream in the induction passage to thereby receive the impact of said air stream. The passage or conduit I30 is controlled by a valve I36, there being control means, indicated generally at I31, for controlling the valve I36. The control means I31 includes a diaphragm I38 to which said valve is Secured-said diaphragm forming one wall of a chamber I40 provided in a wall of the carburetor body which chamber is connected with passage I34 so that it and the respective side of the diaphragm is subjected to entering air pressure or the pressure of air in entrance portion 36 of the induction passage. A hollow casing member I42 is secured to the carburetor body by screws or the like (not shown) and marginally secures the diaphragm which also forms one wall of a chamber I44 within said casing member. A conduit I46 connects the chamber I44 with the induction passage posterior to the throttle 38 so that said chamber and the respective side of diaphragm I38 may be subjected to intake manifold pressure, or engine suction. A pair of diaphragm reinforcing washers I48 and I50 are secured to the central portion of the diaphragm I38 in any well known manner such as a rivet (not shown) and the edge portions of said washers are turned outwardly from the diaphragm. The washer I50 receives one end of a spring I52, disposed within chamber I44, which spring reacts between said washer and a spring retainer head I54 of a screw I56 threaded into an opening therefor in the end wall I58 of easing member I42. The screw I56 provides means for manually adjusting the Operation With the engine running at idling speed and the throttle valve 38 in the idling position engine suction is transmitted through the conduit I46 to the chamber I44 which is thus subjected to suction posterior to the throttle valve 38 and as said suction is high when the throttle valve is in the idling position and the chamber I40 is at substantially atmospheric pressure the diaphragm I38 will be moved to the right, as shown in the drawings, thereby fully opening the valve I36 and permitting substantially full engine suction to be transmitted through conduit I30 to the chamber 18 of the regulator 22. This high suction in chamber 18 is modified somewhat by air bled thereto through conduits I34 and I32 at substantially atmospheric pressure but at idling said suction will be at substantially maximum so that the effect thereof will be to provide maximum closing force for valve 80 and thus limit the flow of fuel to the induction passage to that desired for'the usual mixture for idling. It is to be noted that the fluid force primarily employed herein to act on the diaphragm I4 is engine suction and the air from the air inlet is bled to chamber I8 in a limited amount due to the calibration of the restriction I64 in conduit I32.

As the throttle valve 38 is opened through the near idling range and cruising range the suction in chamber I44 is reduced whereupon the valve I36 is accordingly closed an amount directly related to the reduction of suction in said chamber and to the pressure in passage I34. The partial closing of valve I36 reduces the suction transmitted through the conduit I30 to the chamber I8 thus reducing the force urging the valve in the closing direction and thereby permitting a corresponding increase in fuel pressure beyond the regulator 22. At high engine speed, with the throttle valve 38 opened a substantial amount the suction posterior to said valve 38 will be substantially diminished so that the valve I36 will be closed or substantially closed and little or no suction will be transmitted from the induction passage to the chamber I8. Due to the high velocity and relatively large quantity of air entering the carburetor and passing through the induction passage the suction in chamber I8 will be substantially reduced over that for less open throttle positions and lower engine speeds, therefore the force urging the valve 80 closed is substantially reduced, so that the pressure of fuel posterior to the regulator will be correspondingly increased and the fuel mixture will be enriched to provide a suitably enriched mixture for high speed and power.

The present arrangement is also useful for acceleration purposes. For example, should the throttle valve be in the idling or near idling position and then suddenly opened, the suction posterior to said valve will suddenly drop and the decrease in suction will be effective in chamber I44 to result in closing or substantially closing the valve I36. The suction in chamber I8 will accordingly drop and reduce the pressure urging the valve 80 in the closing direction so that the pressure of the fuel posterior to the regulator will rise sharply and result'in increasing the proportion of fuel in the fuel mixture. Thus a suitable mixture for acceleration is provided.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely the preferred embodiment thereof.

I claim:

1. In a fuel supply system for an internal combustion engine; an induction passage controlled by a throttle; a fuel pump adapted to supply fuel at a substantially constant pressure; a fuel nozzle for discharging fuel into the induction passage; a conduit connecting the fuel pump with the nozzle; a fuel valve controlling the discharge of fuel from said nozzle; a member in the induction passage anterior to the throttle adapted to be actuated by air flow through said induction passage; means connecting said member and valve; regulating means including a diaphragm adapted to control the fuel pressure anterior to said fuel valve and posterior to said pump; means for controlling the regulator including a connection with the induction passage posterior to the throttle valve for subjecting the diaphragm to engine suction; and means responsive to engine suction for controlling said connection.

2. In a fuel system for an internal combustion engine: an induction passage having an air inlet and a, mixture outlet controlled by a throttle; a fuel discharge nozzle; a source of fuel at substantially constant pressure; means connecting said source with the nozzle; means, including a fuel valve, responsive to air flow through the induction passage for controlling the discharge of fuel from the nozzle and adapted to maintain a substantially constant fuel to air mixture ratio for cruising operation of the engine; regulating means for controlling the fuel pressure anterior to the fuel valve and posterior to said source of fuel; means for controlling the regulator in accordance with engine suction and the pressure of air at the inlet of the induction passage; means, including a valve, for varyin the effect of said engine suction on said regulator, said means including a diaphragm connected to the last mentioned valve for controlling said valve in accordance with engine suction and air inlet pressure.

3. In a fuel supply system for an internal combustion engine: an induction passage with a throttle therein; a fuel conduit having a nozzle adapted to discharge fuel into the induction passage; means for supplying fuel to the conduit at a substantially constant superatrnospheric pressure; a valve for regulating the discharge of fuel from said conduit; a means including a vane disposed in said induction passage and a, cam actuated thereby for controlling said valve; a fuel pressure regulating means, including a diaphragm, controlling the pressure of the fuel delivered to the nozzle by the first mentioned means; means including a passageway for subjecting the diaphragm to suction in the induction passage posterior to the throttle; means, including a diaphragm controlled valve, for controlling said passageway, and means for subjecting the second mentioned diaphragm to engine suction posterior to the throttle.

4. In a fuel system for an internal combustion engine: an induction passage having an air inlet and a mixture outlet; a throttle controlling said outlet; a fuel conduit having a nozzle adapted to discharge fuel into said induction passage means responsive to air flow through the induction passage for controlling the flow of fuel from said nozzle; fuel pressure regulating means, including a diaphragm, controlling the pressure of fuel delivered to the nozzle; means including a passageway for subjecting the diaphragm to suction in the induction passage posterior to the throttle; means, including a. diaphragm controlled valve, for controlling said passageway; and means for 8 subjecting the second mentioned diaphragm to engine suction in induction passage posterior to the throttle.

5. In a fuel supply system for an internal combustion engine: an induction passage having an air inlet and a mixture outlet controlled by a throttle; a fuel conduit having a nozzle for discharging the fuel into said induction passage; a regulating means for controlling the fuel pressure in said conduit; a means for controlling the regulator in accordance with engine suction and the pressure of the air at the inlet of the induction passage; means including a valve for varying the eflect of said engine suction on said regulator, said means including a diaphragm connected to the last mentioned valve for controlling said valve in accordance with engine suction and air inlet pressure.

6. In a fuel system for an internal combustion engine: an induction passage having an air inlet and a mixture outlet controlled by a throttle; a fuel discharge nozzle; a source of fuel at a substantially constant pressure; a means connecting said source with said nozzle; regulating means for controlling the fuel pressure posterior to said source of fuel; means for controlling the regulator in accordance with engine suction and the pressure of air at the inlet of the induction passage; and means including a valve for varying the effect of said engine suction on said regulator, said means including a diaphragm connected to the last mentioned valve for controlling said valve in accordance with engine suction and air inlet pressure.

EMIL 0. WIRTH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,972.374 Brannigan Sept. 4, 1934 2,136,959 Winfield Nov. 15, 1938 2,156,115 Gistucci Apr. 25, 1939 2,224,472 Chandler Dec. 10, 1940 2,227,267 Lozivit Dec. 31, 1940 2,232,392 Kittler Feb. 18, 1941 2,238,333 McCain Apr. 15, 1941 2,316,327 Garretson Apr. 13, 1943 FOREIGN PATENTS Number Country Date 452,761 Great Britain Jan. 27, 1942 his, M