US2816745A

US2816745A - Fuel injector

Info

Publication number: US2816745A
Application number: US503753A
Authority: US
Inventors: William G Mccain
Original assignee: Individual
Current assignee: Individual
Priority date: 1955-04-25
Filing date: 1955-04-25
Publication date: 1957-12-17
Anticipated expiration: 1974-12-17

Description

Dec. 17, 1957 w. G. MCCAIN 2,816,745

FUEL INJECTOR Filed April 25, 1955 FUEL INJECTOR William G. McCain, Brookline, Mass.

Application April 25, 1955, Serial No. 503,753

4 Claims. (Cl. 261-23) The present invention relates to improvements in fuel injection system for internal combustion gasoline engines and more particularly to the adaptation of a low pressure fuel injection system to present existing engines, in which a commercial form of low pressure fuel pump is employed, in the manner disclosed in prior United States Letters Patent No. 2,238,333, granted April 15, 1941, upon application of the present inventor.

The use of the low pressure fuel injection system of the prior patent, above noted, has many advantages over those systems employing higher fuel pressure, primarily because with a lower pressure a greater ease in control of fuel flow is obtained with less complicated fuel lines and metering components. Accordingly, it is a purpose of the present invention to obtain the benefits of such low pressure system for injection of fuel at each individual outlet of a plural outlet manifold for a multicylinder engine without the usual objectionable results in the way of inefiicient idling and improper power fuel proportioning action heretofore found in gasoline engines of such nature, as distinguished from engines having a central carburetor with a single power jet serving for several cylinders.

Other objects are to simplify and improve generally the operation of a multicylinder internal combustion engine at the type employing any form of volatile liquid fuel.

While the invention is applicable to use with multicylinder engines many benefits of the invention are obtainable in connection with single cylinder engines or those in which the fuel for full power operation is introduced under pressure at a point in an elongated manifold of the low velocity type as far away as may be necessary from a central air control valve while the fuel for idling is introduced as close as possible to the air control valve.

In the attainment of the purposes set forth, the present invention provides a low velocity intake manifold for a multicylinder internal combustion engine, which manifold is constructed with a central air inlet tube and a plurality of outlets, individual power nozzles being mounted in the outlets, a central idling jet entering the inlet tube close to an air control valve in the inlet tube, and control connections are provided for stopping the flow of fuel to the idling jet when the power nozzles are supplied with fuel. In this way the proportioning of mixture of the engine in all its cylinders is not disturbed by uneven flow of fuel from the idling jet under full power operations. It is also within the purview of the invention to stop the flow of fuel to the power nozzles when fuel is supplied to the idling jet. The transition from one condition of engine operation to the other is accomplished readily by linkage including a floating lever connected at three remote points, one to an idling jet fuel control valve, and another to a power nozzle fuel control valve, and a third to a vacuum controlled piston, the cylinder for which has impressed upon it the suction produced in the manifold. In this way the jet and nozzle leakage or dribble is kept from interfering with the mixture proportioning both unice der idling and power operating conditions in the engine to which the manifold is connected.

These and other features of the invention will readily be apparent, as hereinafter described and claimed, when taken in connection with the following detailed specification and the appended drawings, in which:

Fig. 1 is a perspective view, looking from the front and right side of a plural outlet manifold for a multicylinder internal combustion engine embodying the features of the present invention;

Fig. 2 is a detail perspective view, partly broken away and shown in section and in separated relation, on a larger scale than that of Fig. 1;

Fig. 3 is a sectional view on a further enlarged scale of a power nozzle in an outlet to the manifold of Fig. 1; and

Fig. 4 is a sectional detail view of a fuel metering valve for the power nozzles.

The fuel injector shown in the drawings consists of a low velocity type intake manifold for a multicylinder internal combustion engine, which manifold is formed with a central air inlet tube and a plurality of outlets, one for each cylinder, each outlet being provided with an individual power nozzle mounted in its center. In the past a serious difliculty has been encountered in such manifold arrangement by reason of lack of smooth flexible fuel and air proportioning regulation between idling and full power operation. When the fuel is supplied by power nozzles only without the use of a separate idling jet too much fuel is admitted to each cylinder for smooth idling when an attempt is made to regulate accurately at each nozzle, the nozzles being too large for proper atomization with small amounts of fuel required in smooth idling, especially when high fuel pressures are employed. Neither is it desirable to depend for control of fuel in such manifolds upon air flow with vacuum regulated fuel valves connected to Venturi restrictions in the inlet, since restrictions interfere with free flow of air in a low velocity manifold under high power requirements. With interference of free air flow the greatest benefits of individual fuel injection systems are defeated. Thus, in the present system the full benefit of a low velocity intake manifold with fuel injection is retained by the use of mechanical mixture regulating connections between an air control valve in the manifold inlet and a fuel control valve for the power nozzles, the arrangement including connections for admitting flow of fuel to an idling jet mounted in the air inlet tube in close proximity to the air control valve when the air control valve is closed and for stopping flow of fuel to the idling jet when the air control valve is opened. In this way the problem of regulating the flow of small amounts of fuel through relatively large power nozzles without proper atomization is avoided. Furthermore, the additional problem of power nozzle dribble, commonly afflicting prior fuel injector systems is avoided, whether the system is provided with central power and idling controls or, in the case of the present system with individual power nozzles at the outlets of the manifold. The mechanical connections also act on a power control metering valve for closing it when the fuel flows through theidling jet.

Referring more particularly to the drawings, the manifold is indicated at 11, the inlet tube at 2, the air control valve including a shaft 3 and a vane 4 on the shaft and the mechanical connections including an operating arm 5, a sector shaped cam 6 pivoted on a fixed fuel conducting block 16, a roller 7 rotatable at one end of a lever 8, in turn, rotatable loosely on a horizontal shaft 9 and a spring 10 compressed between the lever 8 and an angular arm 11 (see Fig. 2) secured to the shaft 9. The arm 5 is connected to the earn 6 by a link 36 pivoted at its ends on screws threaded into the arm and cam. The shaft 9 has fixed on its central portion the hub of a forked arm 12 and is rotatable in ears extending horizontally from the inlet tube 2 in the manifold. Within the fork of the arm 12 is a metering pin 13 having a head beneath which the fork of the arm 12 acts as a control for power fuel supply. The pin 13 and a seat in the block 16 form the valve for this purpose and the pin enters a sleeve 130 rising from the block to open or close a lengthwise passage therein by which the fuel enters. The passage is indicated at 37 and bypasses the power fuel control valve to supply fuel to the idling jet, as will be described. Surrounding the pin 13 is a coil spring 27 confined by a shoulder at the upper end of the sleeve 130 and disposed to hold the power valve closed yieldingly. The connections thus described are arranged to open the power fuel control valve when the air control valve is opened and to close the power con trol valve when the air control valve is closed.

The power fuel control valve feeds fuel from the con ducting block'16 through'passageways 17 in aT-shaped side projection 15, there being one'projection at either side of the block 15. Through the projections of the block fuel is fed in opposite directions from the main body portion of the block to the various cylinders of the engine by way of a series of tubes 18 running to the projections from each of a series of individual power nozzles 26, one being mounted in the center of each manifold outlet directly above each intake valve.

The mixture regulating connections also include idle fuel valve controls. Whereas, the roller 7 engages a more or less radial surface on the sector shaped cam 6, an arcuate surface of the cam has a recess and is arranged to be engaged by a second follower roller 35 rotatably mounted at one end of a lever 34 acting on the idle fuel valve, comprising a pin 31 and a seat in the block 16 into which the pin 13 enters. Lifting pin 31 from its seat causes fuel to fiow from the passage 37 to an idling jet 33 past an idling adjustment screw 32 of the usual form. To lift the pin 31 from its seat the lever 34 is fixed to a horizontal shaft 29 rotatable in the ears of the manifold inlet tube 2. Also fixed to the shaft 29 is a forked arm surrounding the upper end of the pin 31 beneath a head engaged by the arm 30. Surroundingthe pin 31 is a coil spring 27 confined by a shouldered upper end of a sleeve 2330 rising from the block 16. The spring 27 acts to hold the idle fuel valve-normally closed but when the recess in the earn 6 moves under the roller the idle fuel valve is opened by suction in the manifold inlet tube 2. The arrangement of'the idle fuel valve connections is such that flow of fuel is admitted to theidling jet when the air control valve 4 is closed and the idle fuel valve is closed when the air control valve is opened. This occurs when the power fuel control valve is opened with the opening of the air control valve. The idling jet 33 is located in the inlet tube 2 in close proximity'to the air control valve 4 where there is a maximum of turbulence in the air so that thereis no necessity for a Venturi restriction in the inlet tube.

To assist in opening and closing the power and idle fuel control valves the shaft'9 has secured to it an arm 19 pivotally connected through a link 20 to a point at one end of a floating lever 23'capable of free bodily movement. The floating lever 23 has another point at its other end pivotally' connected to a link'280 also pivotally connected to an arm 28 secured to the shaft 29, the action being such that the floating lever 23 is movable about any one of three separated points along its length as a fulcrum. The third point along the lever is at an intermediate location where a pivotal connection is made with a piston '22 sliding within a cylinder 21. The cylinder 21 is connected'by a tube 24 with the air inlet tube 2 of the manifold below the air control vane. Thus when the air control valve is nearly closed by theva'ne a strong suction or vacuum acts through the tube 24 to draw the piston downwardly into the cylinder, causing the shaft 9 to be rotated against the action of the spring 10 in a direction to close the power fuel control valve. The suction also tends to open the idle fuel valve by raising the pin 31 from its seat in the conducting block 16. if the cam 6 is moved to a position where the roller 5 fits within the recess of the cam the idle fuel valve is positively opened by the suction in the cylinder 21 and the engine to which the manifold is attached is operated at idling speed. If the pressure in the manifold should decrease by reason of an engine speed reduction, the shaft 9 is rotated by the spring 10 to inject a small additional amount of fuel through the power fuel control valve. This additional fuel increases the engine revolutions suffciently to restore the idling speed and the vacuum within the manifold. In this way a particularly stable speed regulation is obtained in the engine under idling conditions.

With the air control vane 4 nearly closing the air control valve and the engine to which the manifold is connected idling, fuel flows through the idle fuel valve, past the pin 31, which acts to meter the idle fuel, the pin disengaging its seat in the block 61. The vacuum in the manifold holding the pin away from its seat is limited in the amount of movement which it imparts to the pin by the depth of the recess in the periphery of the cam 6, the roller floating within the recess to a certain extent. It will be noted that the forked arm 30 extends to the same side of the shaft 29 as does the forked arm 12 on the shaft 29, but that the arm 28 is on the opposite side of the shaft 29 from that at which the arm 19 projects from the shaft 9. Thus, the suction in the manifold tends to open the idle fuel control valve but tends to cause the power fuel control valve to close. When the engine is operating under full power the reverse is true, any decrease in manifold suction or degree of vacuum causing the idle fuel control valve to close and the power fuel control valve to open under the action of the spring 10.

When the engine comes to rest and no suction exists in the manifold both the idle and power fuel control valves are closed by their respective springs, the strength of the spring 10 being insufiicient to open the power fuel valve when the air control valve is closed and the arm 5 and the cam 6 are moved to the extreme right as they normally would be when the engine is stopped. Thus, there is no leakage of fuel from these valves when the engine operation is discontinued.

The' nature and scope of the invention having been indicated, and a particularly defined embodiment having been described, what is claimed is:

1. A fuel injector for an internal combustion engine, having'a low velocity intake manifold with a central air inlet tube and a plurality of outlets, an individual power nozzle mounted in the center of each manifold outlet, an air control valve in the inlet tube, a fuel tube running from each power nozzle,-a power fuel control valve connected to all the fuel tubes, mixture regulating connections including a cam and a follower roller between the air control valve and the fuel control valve to change the fuel supply to the nozzles as the air control valve is opened or closed, an idling jet entering the air inlet tube, and an idle fuel valve for controlling the flow of fuel to the idling jet, in combination with idling connections including a second followerroller acting on said cam and having a lever acting on the idle fuel valve for admitting flow of fuel to the idling jet when the air control valve is closed and for closing the idle fuel valve when the air control valve 'is opened.

2. A fuel injector for an internal combustion engine, havinga low velocity intake manifold with a central air inlet tube and a plurality of outlets, an individual power fuel-nozzle' mounted in each manifold outlet, an air control valve'in the 'ihlet tub'e, a fuel tube running from each power nozzle, a power fuel control valve connected to all the fuel tubes, mixture regulating connections between the air control valve and the power fuel control valve to change the fuel supply to the nozzles as the air control valve is opened or closed, an idling jet entering the air inlet tube, and an idle fuel valve for controlling the flow of fuel to the idling jet, in combination with idling connections between the air control valve and the idle fuel control valve for admitting flow of fuel to the idling jet when the air control valve is closed and for stopping the flow of fuel to the idling jet when the air control valve is opened, and manifold vacuum controlled means tending to open the idle fuel control valve and to close the power fuel control valve upon increased suction in the manifold.

3. A fuel injector for an internal combustion engine, having a low velocity intake manifold with a central air inlet tube and a plurality of outlets, an individual power nozzle mounted in each manifold outlet, an air control valve in the inlet tube, a fuel tube running from each power nozzle, a power fuel control valve connected to all the fuel tubes, mixture regulating connections between the air control valve and the power control valve to change the fuel supply to the nozzles as the air control valve is opened or closed, an idling jet entering the air inlet tube, and an idle fuel valve for controlling the flow of fuel to the idling jet, in combination with idling connections be tween the air control valve and the idle fuel control valve to change the fuel supply to the idling jet when the air control valve is opened or closed, and manifold vacuum controlled means tending to close the idle fuel control Valve and to open the power fuel control valve upon decreased suction in the manifold.

4. A fuel injector for an internal combustion engine, having a low velocity intake manifold with a central air inlet tube and a plurality of outlets, an individual power fuel nozzle mounted in each manifold outlet, an air control valve in the inlet tube, a fuel tube running from each power nozzle, a power fuel control valve connected to all the fuel tubes, mixture regulating connections between the air control valve and the power fuel control valve to change the fuel supply to the nozzles as the air control valve is opened or closed, an idling jet entering the air inlet tube, and an idle fuel valve for controlling the flow of fuel to the idling jet, in combination with idling connections between the air control valve and the idle fuel control valve for admitting flow of fuel to the idling jet when the air control valve is closed and for stopping the fiow of fuel to the idling jet when the air control valve is opened, and manifold vacuum controlled means tending to open the idle fuel control valve and to close the power fuel control valve upon increased suction in the manifold, said idling connections including a floating lever connected at one point to the power fuel control valve and at another point to the idle fuel control valve, a cylinder connected to the manifold and a piston connected to a third point on the floating lever tending to open the idle fuel control valve upon increase in manifold suction and to close the power fuel control valve when the degree of vacuum is decreased in the cylinder.

References Cited in the file of this patent UNITED STATES PATENTS 2,150,081 Schorsch Mar. 7, 1939 2,313,366 Schweir Mar. 9, 1943 2,320,012 Riall May 25, 1943 2,428,377 Morris Oct. 7, 1947 2,502,679 Stanly Apr. 4, 1950 2,611,595 Streed Sept. 23, 1952