US1951215A - Fuel pump - Google Patents

Description

March 13, 1934. A. A. SIDNEY 1,951,215

FUEL PUMP Filed Feb. 16, 1933 UNITED-STATES PATENT OFFICE FUEL PUMP Arthur Alexander Sidney, Thornton Heath, England, assignor to Bryce Limited, a company of Great Britain Application February 16, 1933, Serial No. 657,115 In Great Britain January 21, 1932 1 Claim. (Cl. 103-41) The invention relates to pumps for supplying grammatically by way of example in the acfuel to internal combustion engines and more companying drawing, in which Fig. 1 shows a pa a y t pumps of t p i which u part of a fuel pump for internal combustion is drawn or forced into a cylinder from where it engines, including a plunger disposed within a is, expelled by a plunger sliding therein with a sleeve member and adapted for axial rotation 60 constant stroke. relatively thereto.

The object of the invention is to provide a Fig. 2 is a side elevational view of the sleeve pump of the type set forth, from which fuel is showing the by-passing ports therein and expelled only during the middle and latter por- Fig. 3 is a diagrammatic representation showtions of the plunger stroke, and in which the ing the development of one of the ports in the 65 duration of the working portion of the stroke sleeve and illustrating the relative positions of may be shortened or lengthened, as and when the diametral passageway in the plunger with desired, the commencement of the pumping ocrespect to this port for various fuel deliveries curring always at the same point in the stroke of the pump.

of the plunger. Referring to the drawing, the pump com- 79 According to the invention the plunger is proprises a vertically disposed cylindrical sleeve vided at a short distance from its working face 1 which is secured within the pump casing 2. with a diametral hole, and an axial or longi- The sleeve is provided with two diametrally tudinal hole is drilled in the working face of the disposed ports 3 and 4 whereby the interior P Which terminates at the other end in of the sleeve may be put into communication the diametral hole. The cylinder is provided ith n a nular channel 5 in the pump casing, with a P With p 0f diametral-1y surrounding the sleeve. This channel 5 composed ports, which are so positioned in the cylmunicates t a passageway 6 connecfed' t a inder as always to be uncovered by the plunger supply of fuel under pressure The upper end durin t i i i l p i of i working stroke, of the sleeve 1 is provided with a seat which and to (lo-Operate to a greater lesser extent is closed by a steel ball valve 7 biased thereto the diametral h01e the plunger during a coil spring 8 a pressure omewhat the final portion of the working stroke of the excess of the supply pressure of the fueL This Plunger- T Plunger and cylinder are arranged spring pressure serves to maintain the ball 7 for axial rotation relatively to one another to seating until the pressure exerted by the brmg diametral hole the Into fuel within the sleeve 1 increases substantially operatlon wlth the ports m the cylinder to a above that at which the fuel is supplied thereto greater or lesser extent. Preferably, the plung- The spring 3 is housed within a union member ng is mounted for i p relatively to the 9, which is screwed into the upper end of the W mder and the cylinder is conveniently constipump casing 2 and serves to retain the Sleeve 1 tuted-by a sleeve member secured within the in pocmofi in the caring A bore 10 in the pump body.

The edges of the by passing port or ports union member communicates with a pipe leadmg to the engine. which determine the termination of the initial Th 1 d f th 1 1 1 d b by-Dassing and the commencement of the final 1 owel if. 8 S i c y a by-passing are preferably inclined with respect uner w 1c 15 adapted o be reclprocated to each other. Conveniently the ports are of trigig sgg i gz i fi i gg g gg iggiii angular shape with upper edges pelpen between the cam 12 and the plunger 11, but for dicular to the axis of the cylinder. The greatsimplicity it has not been shown in the drawing. 10o

est axial distance between the two working edges of the port ports is always greater The working face 13 of the plunger is arranged than the distance between the working fac of so that in its lowest position, as denoted by a,

the plunger and the nearest edge of its diametral 2, it coincides with the lower ends of the hole. ports 3 and 4. The plunger has an axial hole 53 One or more additional, diametral holes may 14 extending for a short distance from its work- 105 be provided in the plunger so as to iing face 13 to a diametral hole 15 drilled through cate with the axial hole, in which case corree pllmgell In the uppermost position of the spending pairs of Icy-passing ports are provided plunger, as denoted by the level I), (Fig. 2), in the cylinder. attained by the working face 13, the lower edge The invention is illustrated somewhat diaof the diametral hole 15 is slightly below the 1 upper edge 16 of the port 3 and the corresponding upperedge of the port 4.

On the lower end of the plunger 11 is cottered a collar 1'? provided with two diametral projections 18. These projections engage in vertical slots 19 cut in a tubular member 20 which is mounted for afilimited rotation in the pump casing. The upper end of the tubular member 20 is formed with teeth 26 which are engaged by teeth in a rack 21 mounted for longitudinal movement within the pump casing. A helical spring 22 is interposed between a shoulder on the sleeve 1 and the collar 17 to bias the plunger 11 against the operating cam 12.

The operation of the pump may best be understood by referring to the diagram Fig. 3. In this figure the horizontal lines A A and B B denote the lower and upper limits of the stroke of the working face 13, of the plunger 11 with respect to the port. It will be understood that the action of the port 4 is exactly the same as that of the port 3, the diametral position of the ports serving to'balance the plunger hydraulically and also against side thrust, thereby eliminating uneven wear on the sleeve or plunger to a considerable extent. The horizontal lines 0 C and D 'D denote the extreme lower and upper positions respectively of the centre of the diametral hole 15 in the plunger. When the plunger is rotated relatively to the sleeve so that the centre of the diametral hole 15 is in alignment with the vertical edge 24 of the port 3, the pump bypasses during the whole portion of its stroke and. no fuel delivery occurs. It will be seen that during the movement of the working face 13 of the plunger from the level A A to'the upper edge16 of the port'3, fuel is by-passed from the chamber 25 through the ports 3 and 4 into the annular chamber 5. Just before the Working face 13 reaches the edge 16 of the port, the diametral hole; 15 has'already passed above the lower ,corner of the port 3 and by-passing also commences through the axial hole 14 and diametral hole 15 to the annular channel 5 through the ports 3 and 4. After the working face 13 has moved above the edge 16, of the port, by-passing occurs solely through the passageway 14 and 15 until the end of the stroke in which position the hole 15 is still in communication with'the annular channel 5 through the ports'3 and 4 as shown at 1511. In this relative position of the plunger and the sleeve, it will be seen that by-passing of the fuel occurs during all of the plunger stroke and therefore no discharge from the pump occurs. other extreme relative position of the'plunger 11 with respect to the sleeve 1, in which the diametral hole.15 passes beyond the extreme right-hand corner of the port 3, the maximum pumping action takes place since by-passing occurs only during the passage of the working face 13 from its lowermost position A A to the upper edge 16 of the port. Thereafter duri ing its passage to B B no by-passing of the fuel takes place as the diametral hole 15 does not pass across the port 3.

It will be evident that between the two extreme relative positions of the plunger and sleeve, any desired quantity of fuel between zero and the maximum value may be pumped by suitable rotation of the plunger 11 with respect In the" to the sleeve 1. Owing to the inclined 'edge 27 of the port 3 and the inclined edge 28 of the port 4 the quantity of fuel pumped will be proportional to the angular rotation of the plunger 11. H

Due to the construction and arrangement of the ports 3 and 4, and the diametral hole in the plunger 11 a symmetrical arrangement is obtained so that the balance of the plunger is not affected by its rotation.

It will be evident that the fuel pump hereinbefore described by way of example only may be modified considerably within the scope of the invention.

I claim: 7

A fuel injection pump for internal combustion engines, comprising a cylinder having near'its inner end a diametrally opposed pair of substantially triangular ports for connection at their outer ends with a source of fuel under pressure, each of said ports having its inner edge normal to the axis of the cylinder and its outer edge extending obliquely to its first named edge and transversely of the corresponding edge of the other port, a plunger adapted to be reciprocated with a constant stroke in said cylinder to alternately uncover and cover said ports during the outer portions of each of its in'gand out strokes, said plunger having a dia metral passageway and an axial passageway extending from its working face to said diametral passageway, the edge of said diametral passageway nearest the working face of said plunger being spaced from said face a distance less than the greatest distance between the said edges of each of said ports of the cylinder and the edge of said diametral passageway furthest. away from the working face of said plunger being spaced at' such distance from said face as to be disposed substantially rearwardly of the edges of said ports which are normal to the axis of said cylinder, when the plunger is at its innermost position, whereby communication between the interior of fthe cylinder and said ports is established through said diametral passageway during the final portion of the instroke of said plunger for by-passing fuel from the cylinder to said ports, the surface of said cylinder inwardlygand outwardly beyond said pair of ports and the surface of said plunger inwardly and outwardly beyond said niametral passageway being smooth and imperforate and forming cooperative bearing surfaces between said plunger and cylinder, thus reducing wear on: the inner edge of said plunger, equal. portions of said ports being disposed on opposite sides of the axis of said plunger to avoid: lateral thrustmn said plunger, said diametral passageway being located near the upper end of said plunger to provide a short passageway between the working face of said plunger and said ports when said'working face passes inwardly beyond said ports, and said ports having sharply defined corners to effect a sudden commencement of the delivery stroke of said plunger, and means for ARTHUR ALEXANDER SIDNEY.

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