US2614494A - Single piston injection pump with fuel distributor for multicylinder combustion engines - Google Patents

Description

2,614,494 ISTRIBUTOR NES 2 SHEETS-SHEET 1 FIG.

In ven/ors W. VOlT ET AL SINGLE PlSTON INJECTION PUMP WITH FUEL. D FOR MULTICYLINDER COMBUSTION ENGI Filed Aug. 31, 1950 M K I 1 9 2 6 I I ////A//|/ Mann w .i I 4 H 4/ V e w w Oct. 21, 1952 1952 w. vorr ETAL 7 2,614,494

- SINGLE PISTON INJECTION PUMP WITH FUEL DISTRIBUTOR FOR MULTICYLINDER COMBUSTION ENGINES Filed Aug. 31, 1950 2 SHEETSSHEET 2 FIG. 10

FIG. 9

Patented Oct. 21, 1952 SINGLE PISTON INJECTION PUMP WITH FUEL DISTRIBUTOR FOR MULTIOYL- INDER COMBUSTION ENGINES Willy viii, Stuttgart-Bad Cannstatt, and Ulrich AldingeryStuttgart-N, Germany, assignors to Robert Bosch G. m. b. H., Stuttgart, Germany Application August 31, 1950, Serial No. 182,536 In Germany October 1, 1948 5 Claims (Cl. 103-2) The invention concerns a liquid distributor, which is especially suitable for supplying fuel by injection to the respective cylinders of a multicylinder (combustion engine through a single working member of a pump, driven at a correspondingly high number of strokes. The rotating distributors used up to the present, possess a disadvantage in that the tight fits of the relatively moving parts necessary for the high working pressures, especially when Working fluids of low viscosity are being used, results in unfavourable sliding capacity, or even in corrosion. These difiiculties, however, do not arise with the use of a reciprocating by-pass slide valve, but as such a slide valve has to travel the same distance twice'during each working stroke, the use of this type of valve consequently entails additional controlling movement and therefore additional moving parts.

This invention aims to avoid the disadvantages appertaining to prior types of distributors by the provision of a cylindrical distributor piston which is driven to reciprocate axially as well as to turn, i. e, to oscillate about its axis. In this method of .driving, which can be effected in a convenient and simple manner, eg by the aid of an inclined or slanted crank, the path of movement of any selected point on the circumference of the'distributor piston is in the form of an ellipse-like curve. Thus, the inlet mouths of supply passages in thepiston which are to be brought into register with. an outlet of the supply passage of the injection pump, are appropriately arranged in' the wall of the piston along the said ellipse-like curve. The possibilities arising hereby are, on the one hand, sufficient register of the mentioned pas- I sages during the injection period, therefore'fsufiicient opening time for the cross sectional areas of the passages and, on'the other hand, to achieve such aspacing between adjoining ports as to ensure a satisfactory high pressure sealing effect along the slidevalve or the pistonsliding surface. Further, the high pressure, sealing effect is influenced' favourably by the tight fits'which are permissible due to the favourable lubrication sup-.1

a working member of a fuel pump which is used either for supplying fuel to the injection pump, or for supplying the lubricant. The working chamber ofthis pump can be formed by theend face of the distributor piston which 'is actuated by the driving member, and the adjacent part of the working surface of the cylinder of thedistributor piston.

The invention is further described by way of example with reference to the accompanying drawings in which: v

Fig. 1 is a longitudinal section of a single unit consisting of an injection pump and a distributor for use in supplying fuel to the respective cylin ders of a four cylinder combustion engine.

Fig. 2 is across section taken on the line IIII of Fig. 1.

Fig. 3 is a plan view of Fig. 1. 1 Fig.4 is a part section through the casing taken on the line IVIV of Fig. 3. v

Fig( 5 is a fragmentary detail view in part section illustrating the drive of the distributor piston, looking towards the driving shaft.

Fig. 6 ,is aside elevation of part of the distributor piston enlarged to twice the scale of the preceding views and looking in the directionmf the arrowVI in Fig. 1, and

Fig. '7 is a development of this part.

Figs. 8 to 11 are cross sections taken on the respective lines VIIIVIII, IX-IX, X-X and XI-XI 'of ,Fig. 6. shows the surrounding casing and associated parts. 1 I

In thefdrawings a, cam shaft IS with a four-' fold cam I1 is mounted in a casing 15 and drives in a known manner a pump piston 18 which is.

mounted for longitudinal displacement in a cyl-i inder bush [9. This piston 18 supplies, at each working stroke, a regulable proportion of the fuel which enters through a supply duct 20 andcommunicating orifice 2| into a. working chamber 22', and then via a pressure valve 23 into a supply passage 24, whilst the surplus remainder of the fuel flows into a duct 26 via a flow return opening 25 from which the fuel can be led through a pipe connection 21 shown in Fig. 3. As with other known pumps also used for a similar pur pose, the flow return duct 26 may be connected directly with the supply, duct 20, ,or itmay form with this duct a common suctionchar'n'ber: if

The quantity of fuel to be supplied through the supply passage 24 is regulated by the turning of the pump piston l8. which is provided with a bevelled or inclined controlling edge 29 and a longitudinal keyway or slot 31. The turningv of the piston I8 is effected by a pinion 33 which is Fig. 8 of these figs. also 3 engaged by a toothed bar or rack 32. The angular position of the piston l8 determines the point in the compression stroke at which the controlling edge 29 uncovers the return opening 25 and thus the proportion of the quantity of fuel which is supplied to supply passage 24.'

Also arranged in the casing l and parallel with the pump piston or plunger I8, is a distributor piston 30 which is adapted to connect in predetermined sequence each of four passages 45, 46, 41 and 48 which are each provided with an outlet pipe connection 35, 36, 31 and 38, respectively, for connection with the injection jet fuel supply lines. Thus the distributor piston 30 thereby connects one of each of the injection jets (not shown in the drawings) of a four-cylinder combustion engine, with the feed passage 24 at the moment in which the pump piston l8 carries out a working stroke. The passages 24, 45, 46, 41 and 48 each have a mouth 54, 55, 56, 51 and 58 (see Figs. 4 and 8) which opens into the cylindrical Working surface of the cylinder wherein the-distributor piston 30 is driven by means of a crank pin 40 which is inclined relative to the camshaft IS. The crank pin 40 carries a yoke 42 (see Fig. 5) fitted with a crank pin bearing 4! whilst a fork 43 formed at the bottom of pistop 38 encloses said yoke 42. This particular form of drive is adapted to impart to the piston 30 a combined axial and oscillatory movement. For-instance, a point on the surface of the piston which as shown in Fig. 1 is at bottom dead center position, and which coincides with the center of the mouth 54 of the supply passage 24, moves through an elliptically shaped path shown in Fig. '7 by the dotted line b. Clearance recesses 65, 86, 6'! and 68 constituting fuel inlets, the. length of which corresponds to the longest required injection period, are arranged in the pistonsurface and following this elliptical path 1).. These clearance recesses are through respective cross. passages 15, 76, TI and 78, which are illustrated in full lines in Figs. 8 to 11 and in chain dotted lines in Fig. '7 in open communication with similar recesses 85, 86, 81 and 88 constituting fuel outlets which are of the same size and shape. These clearance recesses are arranged in spaced locations on the surface of the piston 30 in such manner thatthey cover in course of one rotation of the cam shaft [6 the associated mouths 55, 56, 51 and 58 and thereby open the injection passage to one of the outlet pipes 35, 36, 31 or 38 as soon as the appropriate clearance recess 65, 66, 67 or 68 is in register with the mouth 54 of the supply passage 24. During this short registering period the pump piston [8 cperated by the four-fold cam I! also supplies a quantity-of fuel, corresponding to the angular position of the controlling edge 29 on piston I8, which is fed to the appropriate cylinder of a combustion engine (not illustrated). At the end of a fuel injection operation each two of the associated clearance recesses are covered by the cylindrical working surface of the cylinder wherein the distributor piston 30 is located and driven. Thus sufiicient sealing effect of the injection passages is achieved. In the illustrated example ofconstruction, the center axis of the mouths 54, 55,56, 51, 58 are arranged on a plane at right angles to the axis of the distributor piston and are equidistantly spaced around the piston. The advantage achieved thereby is that the cross passages l5and 11 as also the passages 16 and 18 are .of identical shape and can be produced by drilling on the same drill, jig or other fixture.

The passages 15 and 11 may also, as indicated by chain dotted lines in Fig. 10, be constructed in the form of straight bores connecting the clearance recesses 65 and or 61 and 81. Furthermore, as shown in Fig. 1, the distributor piston 30 can alsobe used as the supply member of an additional pump. The working chamber of this pump illustrated in the drawings is limited by the free end face of the distributor piston 30, the adjoining parts of the cylindrical surface of the cylinder, and a pressure valve 53. The fuel is fed'to this working chamber through a pipe 34 which is connected by a passage 39 with a splayed out circular keyway 5| formed in the cylinder surface. The fuel sealed off in the working chamber thus formed and in the course of one'piston stroke, is displaced via the pressure valve 53 and flows to a circular keyway 52, which is connected with the feed passage 20 of the injection pump.

We claim:

1. A fuel injection pump for a multi-cylinder internal combustion engine comprising the combination of a casing having a pair of parallel spaced bores therein, conduit means for connecting one bore to the other and one of said bores having a plurality of outlet passages, spaced from said conduit means and communicating with the said bore at predetermined spaced points therein, a distributor plunger reciprocating within said last mentioned bore, means for causing said plunger to reciprocate within said bore while simultaneously causing said plunger to oscillate about its axis, said means including a rotatable cam shaft and a crank pin inclined relative to and operatively connected to said plunger and in turn to said shaft so as to be driven thereby and a piston reciprocating in the other of said bores in said casing and operatively connected to said shaft whereby fuel may be continuously supplied through said conduit means from said last mentioned bore to the bore containing said distributor plunger while said distributor plunger ejects fuel into at least one of said outlet passages in the said plunger bore.

2.v A fuel injection pump for a multi-cylinder internal combustion engine comprising the combination of a casing having an elongated bore therein, 'an inlet passage communicating with said bore and a plurality of outlet passages communicating with the said bore and spaced from said inlet passage and each other, a distributor plunger reciprocating within the said bore. means for reciprocating said plunger within the said bore while simultaneously causing the said plunger to oscillate about its axis, said means including a rotatable cam shaft and a crank pin inclined relative to and operatively connected to said plunger and in turn to said cam shaft so as to be driven thereby, and said plunger also having a plurality of spaced bores located therein for registering at predetermined times with the outlet and inlet passages in the said elongated bore in the said casing during the reciprocation of said plunger, said plunger also having elongated recessed portions on the outer surface thereof adjacent certain of the bores therein whereby said inlet passage may be successively connected with said respective bores on said plunger and the outlet passages in said elongated bore during the oscillation of the said plunger.

3. A fuel injection pump for a multi-cylinder internal combustion engine comprising the combination of a casing having a pair of parallel spaced elongated bores therein, conduit means for connecting one bore to the other, and one of said bores having a plurality of outlet passages communicating with the said bore at predetermined vertically and horizontally spaced points therein, a distributor plunger reciprocating within said last mentioned bore, said plunger having a plurality of vertically spaced horizontal bores therein and elongated recessed portions on the outer surface thereof adjacent certain of the said horizontal bores, means for causing said plunger to reciprocate within said bore while simultaneously causing said plunger to oscillate about its axis, said means including a rotatable cam shaft and a crank pin inclined relative to and operatively connected to said plunger and in turn to the said shaft so as to be driven thereby whereby upon rotation of said shaft and oscillation and reciprocation of said plunger said conduit means I for connecting one elongated bore to the other may also be successively connected with the bores in the said plunger and with the said respective outlet passages in said plunger bore during the oscillation of said plunger.

4. A fuel injection pump for a multi-cylinder internal combustion engine comprising the combination of a casing having a pair of parallel spaced bores therein, conduit means for connecting one bore to the other and one of said bores also having a plurality of outlet passages by, a pump piston reciprocating in the other of said bores in said casing and operatively connected to'said shaft whereby fuel may be continuously supplied through said conduit means from said last mentioned bore to the bore containing said distributor plunger while said plunger ejects fuel into at least one of said outlet passages in the said plunger bore and means for returning excess fuel from said plunger bore to said pump piston bore.

5. A fuel injection pump for a multi-cylinder 6 internal combustion engine comprising the combination of a casing having a pair of parallel spaced bores therein, conduit meansfor connecting one bore to the other and one of said bores having a plurality of outlet passages communicating with the said bore at predetermined vertically and horizontally spaced points therein, said outlet passages also being spaced from said conduit means, a distributor plunger reciprocating in said last mentioned bore, said plunger having a plurality of vertically and horizontally spaced horizontal bores therein, means for cause ing said plunger to reciprocate within said bore while simultaneously causing said plunger to oscillate about its axis, said means including a' rotatable cam shaft and a crank pin inclined relative to and operatively connected to said plunger and in turn to the said shaft so asto be driven thereby, whereby upon rotation of said shaft and oscillation and reciprocation of said plunger said conduit means may be successively connected with the said horizontal bores in said plunger and with the respective outlet passages] in said plunger bore during the oscillation of said plunger and a piston reciprocating in the other of said bores in said casing and also operatively connected to the said cam shaft whereby fuel may be continuously supplied through said conduit means from said last mentioned bore to the bore containing said distributor'plunger while said plunger ejects fuel into at least one of said outlet passages in the said plunger bore.

WILLY VOI'I.

ULRICH ALDINGER.

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

I UNITED STATES PATENTS

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