US2445098A

US2445098A - Fuel system

Info

Publication number: US2445098A
Application number: US558713A
Authority: US
Inventors: Emil O Wirth
Original assignee: Bendix Aviation Corp
Current assignee: Bendix Aviation Corp
Priority date: 1944-10-14
Filing date: 1944-10-14
Publication date: 1948-07-13
Anticipated expiration: 1965-07-13

Description

E. O. WIRTH 'July 13, 1948.

FUEL sysmn Filed Oct. 14, 1944- v INVENTOR. Emil 0. Wirf/I Patented July 13, 1948 FUEL SYSTEM Emil 0. Wirth, South Bend, Ind., assignor to Bendix Aviation Corporation,

South Bend,

11111., a corporation of Delaware Application October 14, 1944, Serial No. 558,713

3 Claims. (Cl. 261-37) 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 and contains sub-' Ject matter in common with the following applications: Lei-hing and Fageol, Serial No. 533,848, filed May 3, 1944; Wirth, Serial No. 555,077, filed September 21, 1944, now abandoned.

The above Wirth application teaches the vary ing of the fuel to air ratio of the fuel mixture by varying the effective pump delivery pressure of the fuel to the carburetor, the pumpbeing of the constant delivery type and the present invention provides improved control means for varying said effective fuel pressure.

An object of the present invention is to provide a fuel system of this character of simple construction and having improved performance and economy.

A further dbject of the invention is to provide a device of this character so constructed and arranged as to provide the engine with a lean mixture for maximum economy throughout the lower speed and power range and an enriched above said lower speed range.

The characteristics and advantages of the in- -mixture for maximum speed and POWER ranges vention are further sufficiently referred to in connection with the following detailed description of the accompanying drawings which represents a preferred embodiment thereof. After considering the 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 that are properly within the scope of the appended claims.

The accompanying drawing is a diagrammatical view showing a fuel system as a whole wherein the present invention is embodied.

While the present invention is shown and described in connection with a downdraft carburetor having a movable flow responsive memher in the induction passage for controlling the inflow of fuel to said passage, it is to be understood that the present invention may be used in many other types of fuel systems, such as those employing other flow responsive means and said means may include diaphragms or the like for controlling the metering of the fuel, and in connection with carburetors of the updraft or horizontal delivery type.

The fuel system, as shown, comprises the usual fuel tank Ill connected by a conduit II to a fuel pump ll of known construction. The pump may be of the diaphragm type commonly used on present day automobiles, but for simplicity is shown as a centrifugal pump having a by-pass I6 controlled by a pressure responsive valve I. set for a predetermined pressure. Whatever the type of pump, it should supply :fuel to the carburetor at a substantially constant pressure and should preferably prevent flow through the line when the engine is not operating. An outlet line." leads from the pump to a pressure regulator indicated generally at 22, and thence is conveyed by a conduit 24 to a separating chamber not shown herein but preferably of the character of that shown and described in the above Leibing and Fageol application, there being a return line 26 which conveys excess fuel, together with any vapor which may be present in the line, back to the tank It. The return line 28 is preferably provided, at its point of connection with the chamber, with a restriction (shown in said Leibing and Fageol application) of such size as to permit pressure to be built up in the chamber.

From the separating chamber fuel is conveyed:

to a nozzle 28 of the carburetonindicated generally at 30, the discharge of fuel into the induction passage being controlled by a fuel valve 32.

The carburetor generally The carburetor 30, as illustrated in the draw ings, is substantally the same in construction and operation as that shown in the Leibing-Fageol application above referred to andfcomprises an induction passage including an air inlet portion 36 and a mixture outlet ll controlled by a throttle valve 39. Within the inlet portion 3',

and anterior to the throttle, is a vane or valve 40 fixed to an offcenter shaft 42 so that flow of the air into the carburetor tends to rotate the vane and shaft in a. clockwise direction. A

spring, not shown herein, yleldingly urges the vane in the closing direction. The throttle valve 39 is mounted on a throttle shaft 48 to which is attached a throttle lever 48 having a link connection 50 with the usual accelerator mechanot shown. The usual throttle return spring 52 urges the throttle valve closed. Fuel is delivered 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 I secured to the vane and operably engaging a roller 55 mounted on a lever 51 which has an end 58 adapted to engage the stem 59 of said valve 32. The valve 32 is adapted to be moved in the openingdirection by said lever and is urged in the closing direction by a spring 60, it being noted that the pressure of fuel on the valve has a negligible efifect on the action of said valve, that is the valve is operable substantially independent of fuel pressure thereon.

While the discharge of fuel from the nozzle 28 is herein shown and described as being controlled by the action of air flow on the vane 40, such control may be by means of other air flow means or in accordance with other engine operating conditions. In any event, the control of fuel discharged into the induction passage should be such as to proportion said fuel in accordance with the mass air flow through saidinduction passage, particularly during normal operation of the engine.

The carburetor ,may also include other elements not shown herein but fully disclosed in said Leibing and Fageol application, and referred to hereinabove, which are compatible with the present arrangement.

Fuel regulator Suitable means for regulating or controlling the pressure of the fuel delivered to the carburetor induction passage is provided. The regulator is interposed in. the fuel line between the pump I4 and carburetor and comprises a body having a central casing member 84 which includes an inlet 55 connected with the 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 I secured to the opposite side of the central member 84 by screws T2. A flexible diaphragm I4 is secured between the casing members and 84 thereby separating the interior of the regulator into two chambers I6 and 18. The former chamber is a fuel chamber and fuel therein exerts upward pressure on the diaphragm I4, and the latter chamber is -vented to atmosphere by a vent 19 to prevent undesirable pressures therein such as might interfere with the proper action of the diaphragm. Within the chamber 16 there is a valve, indicated generally at 80, which is connected with the inlet 65 by a conduit 8I. 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 is secured by the overturning at 88 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 valve 80 includes a stem 90 secured to the diaphragm 14 by a nut 92 on a threaded reduced diameter portion.

Washers

94 and 95 on the stem 90 are also secured by the nut 92 and are disposed on opposite sides of the diaphragm for reinforcing 4 tion 84 for urging the movable valve member against the washer". With this arrangement the valve may be effectively closed despite mis alignments between the stem and movable valve member such as may occur from manufacturing variations and the like.

The casing member 10 has a hollow extension IIO having the interior thereof in open communication with the chamber I8 and forming a part thereof. A spring H2 is provided in the chamber I8 and is adapted to react between, the diaphragm washer 94 and a spring retaining head II4 of a plunger II8 which is slidable in a bearing II8 threaded into the upper end, as shown in the drawing, of the extension IIO. A second spring I20, reacts between the bearing I I8 and the head I I4 with a force counterbalancing that of spring II2 on the head H4. A solenoid I22 is mounted in a casing I24 screwed onto the free end of the extension H0 and is so arranged that the plunger IIS is slldably received in the core I28 of the solenoid coil. The upper end of the plunger IIG carries the disk like member I28 which is adapted to be drawn toward the solenoid for increasing the tension oi. spring II2 on the diaphragm I4. Fuel under substantially constant pump pressure, entering the regulator by way of the inlet 65, passes through valve 80 and into the chamber 18 and urges the diaphragm upwardly, as shown in Figure 1, in opposition to the downwardly exerted force of spring II2, so that the valve 80 is controlled primarily by the pressures on opposite sides of the diaphragm and the effective force urging the valve 80 closed determines the fuel pressure posterior to the regulator. Further, with the central portion thereof. The opposite end of the stem 90 has a reduced diameter portion 98 which extends loosely through an opening in the body member 84 of the movable valve member and the outer end of the reduced diameter portion is overturned or riveted at 98, there being a washer 99 disposed between the overturned portion 98 and the body portion 84. A spring I00 disposed about the reduced diameter portion 98 reacts between a shoulder I02 and the body porthe abovearrangement the pressure of fuel to the carburetor may be varied by varying one of the above pressures on the diaphragm 1,4. It is to be noted that by using the counterbalancing spring I20 a slight force only is required to actuate the plunger. Thus a relatively small solenoid may be used.

In the arrangement shown the solenoid is connected by a wire I30 to a source of electric power which is shown as a battery I32 grounded at I34 and the solenoid circuit is controlled by a switch indicated generally at I36 located adjacent the throttle lever. The switch includes an insulated contact point I38 which is grounded at I40 and a second contact point I42 attached to a movable arm I44 and adapted to be moved therewith, said arm being connected by a wire I48 with the solenoid. A lever I48 is rotatably disposed on the throttle shaft 48 adjacent the throttle lever 48, said arm I48 being provided with an adv justable stop member or screw I50 which is adapted to move into engagement with the switch lever I44 and move the contact point I42 into engagement with the point I38 to thereby close the solenoid circuit and efiect energization of the solenoid. Inasmuch as it is desirable to effect closing of the solenoid circuit at some predetermined partly open throttle position, less than the full open position, a yielding lost motion connection is provided adjacent the throttle lever 48 and the arm I48. This includes a lateral extension I52 on the throttle lever and a corresponding extension I54 on the arm I48, a spring I56 being attached to said extensions and adapted to yieldingly urge same toward each other. The throttle lever I48 carries a stop member I58 adapted to be engaged by the extension I54 of the arm I48 and to limit clockwise movement, as shown in the drawin of the arm I48 with respect to the throttle lever 49 and to normally maintain the throttle lever and arm in alignment.

Operation the present invention by the closing of the switch I35 whereby the solenoid is energized and the tension of spring H2 is increased. This results in lessening the force closing the valve 90 which in turn provides a higher fuel pressure to the carburetor and an increase in the ratio of fuel to air. It is to be noted that the throttle valve is only in apartly open position at the time the switch I36 is, closed but due to the lost motion connection hereinabove described full opening of the throttle may be efl'ected.

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 arrangements of the 'parts without departing from the spirit and scope of the invention orsacriilcing all of its material advantages, the form hereinbefore described being merely a preferred embodiment.

I claim:

1. In a fuel system for an internal combustion engine: an induction passage having a throttle therein mounted on a shaft; a throttle lever for said throttle shaft; means for controlling the throttle; a fuel conduit having the metering oriflce therein; a valve responsive to air flow in the induction passage for varying the eifective size of said orifice; means for supplying fuel to the metering orii'ice at a substantially constant pres.- 1 sure; means so constructed and arranged as to vary the ratio of fuel to air forthe engine by' yieldably connected to the throttle lever, and

adapted to actuate the switch at apart open throttle position and permit the throttle lever to be moved beyond the switch actuating position.

2. In a fuel system for an internal combustion engine: an induction passage having a throttle therein; a throttle lever for actuating said throttle; a fuel conduit having an orifice therein; a valve for varying the flow of fuei through said orifice; means for supplying fuel to the orifice at a substantially constant pressure; means so constructed and arranged as to vary the ratio of the fuel to air for the engine by varying the pressure of the fuel supplied to said orifice; an electrical means for controlling the second mentioned means; a circuit for said electrical means;

a switch for said circuit; and a means including a pivoted arm yieldably connected to the throttle lever and adapted to actuate the switch at a part open throttle position.

3. In a fuel system for an internal combustion engine: an induction passage having a throttle therein; a-throttie lever; a fuel conduit having an orifice therein; a valve responsive to air flow in the induction passage for varying the effective size of said orifice; means for supplying fuel to the orifice at a substantially constant superatmospheric pressure, said means being so constructed and arranged as to vary the ratio of fuel to air for the engine by varying the pressure of the 'fuel supplied to said orifice; an electrical means for controlling said first mentioned means comprising an electrical circuit, a switch for said circuit, a pivoted arm yieidably connected to the throttle lever and adapted to actuate the switch as the throttle valve is moved toward open position.

EMIL 0. WIRTH.

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

UNITED STATES PATENTS Number Name Date 2,136,959 Winfield Nov. 15, 1938 2,159,173 Mennesson May 23, 1939 2,225,943 Schweiss Dec. 24, 1940 2,392,055 Mennesson Jan. 1, 1948 I I'OREIGN PATENTS Number Country Date 401,824 Great Britain Nov. 10, 1933 452,248 Great Britain Aug. 19, 1936 493,252 Great Britain Oct. 5, 1938