US3027844A - Fuel pumps for compression ignition engines - Google Patents

Description

April 1962 J. B. KRUK-STRZELECKI 3,027,844

FUEL PUMPS FOR COMPRESSION IGNITION ENGINES Filed June 2, 1960 Fig. l moan/270p ffifi'z ulfcitrzelccliig Unit 3,27,844 Patented Apr. 3, I962 ice 3,027,844 FUEL' PUMPS FOR COMPRESSION IGNITION ENGINES Jerzy BoleslawKruk-Strzelecki, London, -England,'asslgnor to C.A.V. Limited, London, England Filed June 2, 1960, Ser. No. 33,544 Claims priority, application Great Britain June 15, 1959 2 Claims. (Cl. 103-41) This invention relates to fuel pumps for compression ignition engines, more particularly single cylinder engines, the pump being of the kind comprising in combination a cylinder having a fuel inlet port in its wall, a reciprocable and spring-loaded plunger in the cylinder, said plunger having in its periphery a helical groove, and means for varying the angular setting of the plunger about its axis to determine the instant in a stroke of the plunger at which communication is established between the groove and inlet to vary the quantity of fuel delivered by the pump.

The object of the invention is to provide a pump of the aforesaid kind in a simple and convenient form.

A pump according to the invention and of the kind specified has in combination a sleeve slidably surrounding the outer end of the cylinder, a shoulder on the exterior of said sleeve, an annular abutment plate against said shoulder, a spring surrounding the cylinder and bearing at one end against said plate, a key member engaging a longitudinally extending groove in the cylinder and a hole in the sleeve to prevent relative angular movement, said key member being retained in position by said plate, and a radially extending member at the outer end of the plunger whereby angular movements can be imparted to the plunger, the arrangement being such that movement of the sleeve by the spring will be imparted to the plunger through said radially extending member.

In the accompanying drawings FIGURE 1-is a sectional side view illustrating one example of the invention, whilst FIGURES 2 and 3 respectively are sections on the lines 22 and 33 in FIGURE 1.

Referring to the drawings there is provided a hollow body part 4 having a central bore and a fuel inlet 5 at one side. Secured within one end of the bore of the body part is a head 6 formed at the inner end of a cylinder 7 containing a reciprocable plunger 8. The head 6 is located against a shoulder within the bore of the body part 4 and the cylinder 7 is restrained from angular movement relative to the body part by means of apin 9 extending through the body part into a groove in the periphery of the cylinder. The cylinder 7 has a radial inlet port 10 which is in register with the inlet 5, and the plunger 8 which is adapted to be moved inwardly by the action of a cam 11, incorporates in its periphery a helical groove 12 which is adapted to co-operate with the port 10 in a manner to be described. Also within the bore of the body part 4 is a spring-loaded non-return valve 13 through which fuel can be delivered to an outlet 14 at the end remote from the cylinder 7.

The outer end of the cylinder 7 is slidably surrounded by a sleeve 15 having an external peripheral shoulder, and against the shoulder is an annular abutment plate 16 which serves to support one end of a coiled compression spring 17 surrounding the exposed portion of the cylinder 7 and hearing at its opposite end upon the body part 4. The sleeve 15 is prevented from rotation relative to the cylinder 7 by means of a key member in the form of a ball 18 located partially within a longitudinally extending groove 19 in the periphery of the cylinder 7, and partially within a hole formed in the sleeve 15 adjacent the shoulder. As shown in FIGURE 1, both ends of the longitudinal groove 19 are closed. Moreover, the arrangement is such that the plate 16 overlaps the ball 18 and retains it from disengagement from the hole in the sleeve 15.

Secured to the outer end of the plunger 8 for move ment therewith is a radially extending arm 2% adapted at its outer end for'engagement with a notch in a regulator rod 21 movable axially in a direction at right angles to the axis of the cylinder by a governor or other means (not shown). The arm 20 extends through an arcuate recess at the outer end of the sleeve 15, which is adapted to be moved inwardly simultaneously with the plunger 8 by the action of the cam 11. A small clearance normally exists between the arm 20 and the base of the recess in the sleeve 15. However, when the sleeve 15 is moved outwardly by the action of the spring 17 it bears against the arm 20 and thereby imparts outward movement to the plunger 8. By virtue of the arcuate recess, angular movement of the arm 20 can be effected without angular movement of the sleeve 15. Such angular movement will be imparted to the plunger 8, and thereby eifect the setting of the helical groove 12 in the plunger relative to the inlet port iti so as to determine the instant in an inward stroke of the plunger 8 at which communication is established between the groove 12 and the port 10. The groove 12 is in communication with the inner end of the cylinder 7 in known manner and thus as soon as the groove 12 is in communication with the port it) injection of fuel ceases. Thus the angular setting of the plunger 8 will determine the quantity of fuel delivered by the pump at each reciprocation of the plunger.

By the present invention the sleeve in addition to serving to transmit the spring pressure to the plunger acts as a support for the outer end of the latter due to its guided sliding movement upon the exterior of the cylinder.

Having thus described by invention what I claim as new and desire to secure by Letters Patent is:

1. A fuel pump of the kind specified, comprising in combination a cylinder provided near one end thereof with a fuel inlet, a plunger slidably fitting within the cylinder and extending from the other end thereof, a spring-loaded non-return valve which is mounted at the first mentioned end of the cylinder, and through which fuel admitted to the cylinder is dischargeable therefrom by the plunger, the latter having in its periphery a helical groove, and being angularly adjustable about its axis for determining the instant at which communication is established between the helical groove and the fuel inlet during a discharge stroke of the plunger, a hollow body part within which the first mentioned end of the cylinder is secured, and in which the spring-loaded non-return valve is mounted, a sleeve which surrounds the end portion of the plunger extending from the cylinder, and which is slidably mounted on the adjacent end portion of the cylinder, the said end portion of the cylinder having formed in its outer periphery a longitudinal groove which is closed at both ends, a key member in engagement with, and extending outwardly from, the longitudinal groove in the outer periphery of the cylinder, an annular abutment plate surrounding the sleeve and the adjacent portion of the cylinder, the sleeve being provided at a position intermediate its ends with an external annular shoulder which forms a seating for the annular abutment plate, and being also provided at a position adjacent the shoulder with a hole through which a part of the key member projects into contact with an inner portion of the annular abutment plate so that the key member serves to prevent relative angular movement of the cylinder and sleeve, and is retained in position by the annular abutment plate, a coiled compression spring surrounding the cylinder and bearing at opposite ends respectively on the hollow body part and the annular abutment plate to retain the latter in contact with the annular shoulder on the sleeve, and a member which is secured to the plunger at the end thereof outside the cylinder, and which extends radially from the plunger through an arcuate opening in the adjacent part of the sleeve so that the plunger can be moved angularly about its axis by the said member, and axial movement imparted to the sleeve by the coiled compression spring is transmitted to the plunger by the said member.

2. A fuel pump according to claim 1, wherein the key member has the form of a ball Which at one side engages the longitudinal groove in the outer periphery of the cylinder, and at the opposite side is in contact with an inner portion of the annular abutment plate.

References Cited in the file of this patent UNITED STATES PATENTS FOREIGN PATENTS Great Britain July 23, 1952

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