US3006326A

US3006326A - Fuel supply system

Info

Publication number: US3006326A
Application number: US9291A
Authority: US
Inventors: Barfod Frederik
Original assignee: Bendix Corp
Current assignee: Bendix Corp
Priority date: 1960-02-17
Filing date: 1960-02-17
Publication date: 1961-10-31
Anticipated expiration: 1978-10-31

Description

IN V EN TOR.

ATTORN E Y.

Oct. 31, 1961 F. BARFOD FUEL SUPPLY SYSTEM Filed Feb. 17, 1960 FREDER/K BARFOD.

United States Patent 3,006,326 FUEL SUPPLY SYSTEM Frederik Barfod, Detroit, Mich., assignor to The Bendix Corporation, a corporation of Delaware Filed Feb. 17, 1960, Ser. No. 9,291 3 Claims. (Cl. 123-119) The present invention relates to fuel supply systems for internal combustion engines having an induction passage pressure responsive control for varying the quantity of fuel supplied to the engine and more particularly to temperature and air flow responsive means for varying the induction passage pressure applied to the control.

A fuel supply system for which the present invention is particularly adapted, is disclosed and claimed in my copending application Serial No. 604,483 filed August 16, 1956, now Patent No. 2,930,370, granted Mar. 29, 1960.

It is an object of the present invention to provide in a fuel supply system means for enriching the fuel-air mixture supplied to the engine during starting and warmup operation.

Other objects and advantages of the invention will become readily apparent from the following description taken in connection with the accompanying drawing wherein:

FIGURE 1 shows a schematic view of a fuel supply system embodying the present invention; and

FIGURE 2 is a sectional view taken along lines 2-2 of FIGURE 1.

Referring now to the drawings numeral designates a fuel supply system for supplying fuel to an internal combustion engine 12 which has an induction passage 14 with a throttle 16 mounted therein. Fuel supply system 10 is provided with a housing 18 having an inlet 20 which is adapted to be connected to a source of fuel (not shown) through an appropriate conduit. A pump 22 is mounted in the housing for connection with inlet 20. Appropriate means (not shown) may be provided to rotate pump 22 as a function of engine speed. Also mounted in said housing is a distributor valve 24 adapted to be rotated as a function of engine speed by appropriate means (not shown). Valve 24 is provided with a port 26 located in the side wall thereof which is arranged for successive registration with a plurality of ports 28 formed in the housing 18. The number of ports 28 may conveniently correspond to the number of cylinders in the engine with which the fuel supply system is associated. Each port 28 opens into a discharge conduit 30 having a nozzle 32 secured to one end thereof. The nozzles 32, only one of which is shown, are adapted to inject fuel into the intake manifold of the engine, the number of nozzles may be equal to or less than the number of cylinders of the engine depending on the construction of the intake manifold. The flow through port 26 is controlled by a piston 34 which is mounted for axial movement within valve 24. Piston 34 is responsive to differences in pressure between the pressures in

chambers

36 and 38 located respectively on opposite sides of said piston. Fuel is supplied to chamber 36 from pump 22 via conduit 40 and metering restriction 42. Fuel is supplied to chamber 38 from pump 22 via conduit 40, valve 44 and conduit 46. Chamber 38 is connected to inlet 20 via conduit 46 and restriction 48. A housing 50 projects from the main housing 18 and contains a movable wall 52 which divides the interior of housing 50 into chambers 54 and 56. Movable wall 52 is operatively connected to valve 44. A spring 58 is mounted in chamber 54 to urge movable wall 52 in a direction to close valve -44. A vent 60 is provided in the side wall of housing 50 to connect chamber 56 to the atmosphere.

The induction passage 14 is provided with a port 62 Patented Oct. 31, 196] downstream of the throttle valve 16. A conduit 64 connects port 62 to chamber 54. The movable wall 52 is moved in response to the pressure diflerential between the pressures in chambers 54 and 56 Le. atmospheric pressure and induction passage pressure, to urge Valve 44 toward open position.

An unbalanced air valve 66 is mounted in induction passage 14 on a shaft 68. Air valve 66 is unbalanced so as to be opened by air flow through the induction passage 14. An air valve lever 70 is secured to shaft 66 and is provided at its free end with a pin 72 for engagement with the hooked end of a thermostat 74 which is mounted in a housing on the side of the induction passage 14. The thermostat 74 is exposed to a temperature indicative of engine temperature either directly, by passing heated air through the housing or through the use of an electric heating coil having predetermined characteristics.

In operation, fuel is supplied at substantially constant pressure to inlet 20 from whence it flows to pump 22 where the pressure is increased as a function of engine speed. The pressure of fuel in chamber 36 varies as a function of engine speed and acts against an end face of piston 34 to urge the piston in a direction to increase the fuel flow through port 26. The pressure of fuel in chamber 38 varies as a function of engine speed and induction passage pressure and acts against an opposite end face of piston 34 to urge the piston in a direction to decrease fuel flow through the port 26. Piston 34 seeks a position to balance the pressures in

chambers

36 and 38 and is movable in response to momentary changes in the pressures in either chamber which may be caused by changes in engine speed or induction passage pressure. When the valve 44 is closed the entire output of pump 22 is delivered to the engine through port 26. As the valve 44 is opened a portion of the fuel delivered by pump 22 is by-passed to the inlet 20. The valve 44 is urged toward closed position by spring 58 and toward opened position by a reduction in induction passage pressure in chamber 54.

Air valve 66 is disposed in the induction passage downstream of port 62 so that when the air valve 66 is closed the induction passage pressure communicated to chamber 54 is higher than the induction passage pressure downstream of the air valve and may approach substantially ambient or atmospheric pressure and thus spring 58 is effective to close valve 44 causing an enriched mixture to be supplied to the engine. Air valve 66 is urged toward closed position by thermostat 74 when the thermostat is cold. As the thermostat 74 warms up the force urging air valve 66 towards closed position is reduced. Air valve 66 is urged toward open position by air flow through the induction passage 14. Thus while the thermostat is cold the position of air valve 66 will be determined by the balance of forces acting thereon viz., the force of the thermostat tending to urge it closed and the air flow acting thereon to urge it open. During the starting operation of the engine with the thermostat cold the air valve 66 will be substantially closed and thus the valve 44 will be substantially closed to provide enriched fuel/ air mixture to the engine. As the engine starts and during the warmup operation of the engine the air valve 66 will be partially opened by air flow acting thereon so as to modify the induction passage pressure communicated to chamber 54 so as to continue supplying an enriched fuel/ air mixture. When the engine is fully warmed up and operating the air valve 66 is in substantially wide open position and has little or no effect on the induction passage pressure communicated to chamber 54.

While I have described my invention in its preferred form it will be understood by those skilled in the art that changes in construction from that disclosed may be made Without departing from the underlying principles of the invention.

I claim:

1. A fuel supply system for an internal combustion engine having a source of fuel and an induction passage with a throttle therein comprising a conduit adapted'to connect said source with said engine, a pump in said conduit, a by-pass connected to said conduit on either side of said pump, a valve controlling the flow through said by-pass, a housing, a movable wall in said housing operatively connected to said valve and dividing the interior of said housing into first and second chambers, means venting said first chamber to the atmosphere, a port in said induction passage downstream of said throttle, passage means connecting said port to said second chamber, resilient means in said second chamber urging said wall in a direction to close said valve, an unbalanced air valve mounted in said induction passage downstream of said port, said air valve being urged toward open position in response to air flow through said induction passage and a thermostat operatively connected tosaid air valve for urging said air valve toward closed position.

2. A fuel supply system for an internal combustion engine having a source of fuel and an induction passage with a throttle therein, comprising a fuel meteringdevice adapted for connection to said source and to said engine for delivering metered fuel to said engine, means responsive to induction passage pressure operatively connected to said device for controlling the quantity of fuel supplied to the engine, a port in said induction passage downstream of said throttle, a conduit connecting said port to said first mentionedrmeans, an unbalanced air valve openable in response to air flow mounted in said induction passage means downstream of said port and temperature responsive means urging said air valve toward closed position.

3. A fuel supply system for an internal combustion engine having a source of fuel and an induction passage with a throttle therein comprising a fuel metering device adapted to supply fuel from said source to said engine,

'means operatively connected to said device for controlling the quantity of fuel supplied by said device to the engine, a movable wall operatively connected to said first mentioned means, resilient means urging said wall in direction to move said first mentioned means in a fuel supply increasing direction, an unbalanced air valve in said induction passage downstream of said throttle, means for subjecting said wall to the pressure in said induction passage between said throttle and air valve to urge said wall in a direction to decrease the fuel supply to the engine, and means responsive to a temperature indicative of engine temperature for urging said air valve toward closed position.

No references cited.