US2593551A

US2593551A - Fuel injection pump

Info

Publication number: US2593551A
Application number: US790277A
Authority: US
Inventors: Fodor Nicholas
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-12-08
Filing date: 1947-12-08
Publication date: 1952-04-22
Anticipated expiration: 1969-04-22

Description

April 22, 1952 N. FODOR 2,595,551

FUEL INJECTION PUMP Filed Dec. 8, 1947 2 SHEETS-SHEET 1 I i J 22 i 22 g O i f! I I U 23 o *J 14 II' I' I I; Ii

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April 22, 1952 N. FODOR 2,593,551

FUEL INJECTION PUMP Filed Dec. 8, 1947 2 SHEETS-SHEET 2 1 1/ 12 Nun-3%: w u lllllll i; 6

Patented Apr. 22, 1952 UNITED STATES PATENT OFFICE 5. Clai This invention has to do with fuel injectionpumps, and is particularly concerned with an improved pump of the type in which the quantity of; fuel delivered by the (pump during each injection controlled at the inlet of the :pump. Although capable, of being used for other purposes the newpump is particularly well suited for use in connection with Diesel engines.

The principal object of the invention is to provide an improved pump of the character described having simple yeteiiective means for bypassing excess fuel back into the fuel supply chamber ofthe pump without creating ob-j ectionable turbulence therein.

Otherobjects and advantages of the invention will, be apparent tothose skilled in the art upon a full understanding of the construction, arrangement and operation of the parts entering into theconstruction of the improved pump.

A preferred embodiment of the invention is presented herein for the purpose of exemplification but it will of course be appreciated that the invention is susceptible of incorporation in other structurally modified forms coming equally within the scope of the appendedclaims.

In the accompanying drawings:

Fig. 1 is aside view of a fuel injection pump which has incorporated therein theimproyement constitutingthe present invention;

Fig. 2 is a different side view of the pump;

Fig. 3 is a plan view of the pump;

Fig. 4 is a vertical section throughthe pump, taken on approximately the lined-4 of Fig. 1

Fig. 5 is another vertical section, taken on approximately the line.55 of Fig. 2; and

Fig. 6 is a horizontal section, taken on approximately the line 6.B of Fig. 4.

Referring in more detail to the drawingsit will be observed that the pump is characterized by a body III which is adapted to be bolted or otherwise securely fastened to the associated engine. The body I is provided with a vertical bore and: horizontal bore, l2. Theupper centralportion of the bore ll constitutes, the pumpingchamb'er, whilethe bore. l2 constitutes the fuel inlet chamber.

A plunger l3 reciprocates vertically with a constant length strokewithin the bore I I in freely slidable but fluid-tight engagement with the same. The plunger I3 is moved upwardly by a cam M on the cam shaft of the associated engine and is moved downwardly by a coil spring l6 which is compressed between the underside of the body l0 and a spring seat I1 secured to the lower exposed end N3 of the plunger.

The plunger 13 is provided a predetermined distance below its upper end with an annular groove l9, and the groove I9 is connected to the pumping chamber space above the plunger by radial passages 20 in the bottom of the groove which communicate with a centrally arranged upwardly opening bore 2| in the upper end of the plunger.

The upper end of the, bore l l is closed oil by a delivery valve assembly 22, which assembly includes, a delivery union 23 which is adapted tobeconnected by suitable tubing withthe injector, an annular valve, seat 24 at the lower end of the union, a vertically movablervalve 25 on the seat,

anda small coil spring 26 for pressing, the valve downwardlyagainst the seat. I

The bore l2, whichconstitutes; the-fuel supply chamber, is adapted to be connected at one end with the fuel supply line 21 and isada pted to be closed at its other end by a screw plug 28, either end of the bore I2 being optionally connectable with the fuel supply line.

A fuel quantity control shaft 29 is rotatably mountedin a horizontal position in the body 10, with its center portion as passing crosswise through and exposed within the bore I2, and with its end portions 3| and 32 journalled respectively in aligned bores 33 and 34 in freely rotatable, but fluid-tight engagement with the latter. Onelend of the shaft 29 projects from the body In and is provided with a lever 35 by means of which the shaft is adapted to be turned through a predetermined angle.

The portion 30 of theshaft 29 which is exposed;

within the bore I2 is provided withradial pasedges; 36 which open into a longitudinal extending bore; 3] in the shaft. The bore-31 isvclosed atits far end byascrew plus 38 and is connected with a radial passage 39 which; opensinto anec centrically formed arcuate roove, 40 in the outer surfaceof the shaft. The, groove-40 isformed in that portion of the shaft 291 which isjournalled; withinthe bore, 34, and is-located ata pointdia Thenbore-3'4 is conrectly-oipposite the bore H. nected with the bore II at the. location-ofthegroove. 40 by; an inletzport-A I, which port. opens;- into the-"pumping chamberportion of the borel IE justabove the edgeofr-theltop 4210f thenplunger;

I 3'; when thelatter isin' its. lowermost: position;

Below the inlet port 4| the bore ll connects again with the bore I 2 by a spill port 43-, which port is adapted to communicate with the annular groove l9 in the plunger I3 at a predetermined point in the upward travel of the plunger, whereby to by-pass fuel back into the bore [2.

The improvement which constitutes the presnt invention is the provision in the bore l2 of a special spill deflecting element 44, which element may advantageously consist of a pin 45 which is press fitted or otherwise securely held within a bore 46 in the body It with its axis aligned with the spill port 43 and with its confronting end 41 abruptly formed at right angles to the axis of the spill port. The pin 45 is preferably somewhat larger in diameter than the spill port 43 and is located in direct opposition and in close proximity to the latter. The pin is preferably spaced about of an inch from the discharge end of the spill port, but this spacing may be increased or decreased and yet afford the desired-baffling effect on the fuel.

The pump operates as follows: In the lowermost position of the plunger l3 (which is the position shown in Figs. 4 and 5) fuel from the bore l2 flows through the inlet port 4| into the bore II across the top 42 of the plunger, metered by the restriction determined by the angular position of the fuel quantity control shaft 29. As the plunger l3 moves upwardly in the bore H the top 42 of the plunger cuts off the inlet port 4!, after which the fuel trapped in the bore H above the plunger is forced upwardly past the delivery valve 25 and through the tube leading to the injector. As soon as the plunger H5 in its upward movement reaches a position wherein the groove 19 uncovers the spill port 43 delivery of fuel through the valve 35 abruptly ceases and that fuel which is displaced by the movement of the plunger during the remainder of its upward movement is by-passed through the spill port 43 back into the bore l2.

As the fuel is discharged from the spill port 43 back into the bore [2 it impinges. squarely against the plug-like end 41 of the baffling element 44 immediately upon entering the bore and has its dynamic energy quickly and effectively dissipated. This dissipation, by the means herein disclosed, has been found to materially improve the operation of a pump of this type, preventing pressure waves in the fuel from penetrating into the bore I2 to such extent as to cause therein unwanted momentary increases in the pressure and violent motion of the fuel.

I claim:

1. In a fuel injection pump, a pumping chamber, a constant stroke plunger reciprocally mounted therein, said plunger having a circumferentially continuous head which closely fits the pumping chamber and terminates at its lower end in a laterally opening recess, which recess communicates through the head with an upwardly opening recess in the top of the latter, an outlet port from the upper end of the pump ing chamber adapted for connection with an injector, a fuel chamber for both supplying fuel to the pumping chamber and receiving excess fuel from that chamber, a single inlet port into the pumping chamber from the fuel chamber, which port is located just above the top of the head of the plunger in the lowermost position of the latter, an adjustable metering valve located between the fuel chamber and the inlet port for variably controlling the rate of flow of the fuel from the fuel chamber through said inlet port into the pumping chamber, a single spill port from the pumping chamber into the fuel chamber, which port is located a substantial distance below the inlet port and is closed off from the pumping chamber by the head of the plunger in the lowermost position of the plunger, being placed in communication with the pumping chamber by said laterally opening recess only after the piston has moved upwardly a predetermined distance, and a baiile member located in the fuel chamber adjacent to but spaced from the discharge end of the spill port, in a position in direct opposition thereto, for reducing in the fuel present in the fuel chamber the turbulence which would otherwise be caused by the fuel returned to the fuel chamber through the spill port, without obstructing such return.

2. A fuel injection pump of the construction set forth in claim 1, wherein the baffle member is so arranged as to afford a substantially flat right angular impingement surface for the fuel entering the fuel chamber from the spill port.

3. A fuel injection pump of the construction set forth in claim 1, wherein the baffle member is structurally separate from the fuel chamber and is capable of being adjusted toward or away from the discharge end of the spill port.

4. A fuel injection pump of the construction set forth in claim 1, wherein the bailie member consists of a pin which is secured in a bore in the fuel chamber in substantially axial registration with the spill port and terminates in a substantially fiat end face, which end face is spaced but a small fraction of its diameter from the end of the spill port.

5. A fuel injection pump of the construction set forth in claim 1, wherein the fuel chamber consists of a short bore in right angular laterally spaced relation to the pumping chamber, the adjustable metering valve includes a rotatable operating stem which extends crosswise through said bore and is provided with a longitudinally extending fuel passage which opens radially at one end into communication with said bore and at the other end into communication with the fuel chamber, and the baffle member consists of a pin which extends crosswise of said bore in closely spaced relation to said stem and in substantially axial registration with the spill port and terminates in an end face which is spaced but a small fraction of its diameter from the end of the spill port.

NICHOLAS FODOR.

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

UNITED STATES PATENTS Number Name Date 2,130,521 Brunner Sept. 20, 1938 2,309,074 Edwards Jan. 19, 1943 FOREIGN PATENTS 7 Number Country Date 665,885 Germany 1938