US1999330A - Liquid fuel injection pump - Google Patents

Description

April 30, 1935. R. LORANGE 1,999,339

LIQUID FUEL INJECTION PUMP Filed June 26, 1935 fla/l NVENToR, Lw/m 1 Patented pr. 30,1935 l LIQUID FUEL INJEcrroN PUMP Rudolf LQrange, Stuttgart, Germany, assignor of one-half to Frederick Richard Simms, London, England Application June 26, 1933, Serial No. 677,724 In Germany February 9, 1933 6 Claims..

This invention is for improvements in and relating to liquid fuel injection pumps of the reciprooatingplunger type in which the quantity of fuel delivered by the plunger is regulated by bypassing a variable portion of the fuel (known as the spill) at each delivery stroke by means of a discharge port or passage co-operating with a control edge inclined with respect to the longitudinal axis of the plunger, the port or an end of the passage and the control edge being disposed one on the plunger and the other on the cylinder and the amount of spill being varied by relative rotation between the` plunger and its cylinder so as to vary the moment at which the port crosses the control edge and thereby determine the amount of the spill and consequently the amount of fuel delivered from the pump for injection into an engine cylinder.

In pumps of the above type in which the suction is controlled by means of a port or ports adapted to be covered and uncovered by the plunger acting as a slide valve, without the employment of a suction valve, it is usual for the suction passage opening into the cylinder space of the pump to be utilized for the return iiow of the spill, or for the passages for the suction and spill to be so arranged as to produce eddies in the liquid in the suction passage and interference between the two distinct actions referred to.

It is one of the objects of this invention to overcome the above defect and to provide a fuel injection pump in which the flow of the liquid through the suction passages is effected at all times in the same direction in a similar manner to the flow of steam in a uni-ow steam engine, and thus by the avoidance of reversals in the fluid stream and the elimination of a suction valve which tends by its opening and closing movements to cause oscillations in` the fluid, the formation of eddies in and the production of gas bubbles from the liquid is avoided.

Other features offthe invention are pointed out in the ensuing description and in the appended claims.

In order that the invention may be fully understood, reference is directed to the accompanying drawing, in which:

Figure 1 is a vertical section of the upper portion of a liquid fuel injection pump constructed in accordance with the invention;

Figure 2 is a vertical section at right angles to Figure 1;

Figure 3 is a section on the line 3 3 of Figure l; Figure 4 is a detail of inlet and outlet connections for a pump in accordance with the inven- REISSUED tion, illustrating a modification of Figure l; and

Figure 5 is a view similar to a portion of Figure 1, illustrating'a modified construction of pump in accordance vwith the invention.

Figures l to 3 illustrate the preferred embodiment of the pump in accordance with the invention. In this construction the pump comprises an outer casing I in which a cylinder liner 2 is secured against a shoulder 3 by means of a plug II screwed into the casing and bearing upon the 10 upper ,en'd of the liner through the intermediary of a detachable cylinder head 5 and a packing washer 6; a discharge valve 1 controlled by a spring 8 is seated on the cylinder head and controls the discharge passage 9, the spring 8 react- 15 ing against a discharge pipe union I0 secured to the head 5 by a union nut II.

A plunger I2 is arranged to be reciprocated in the bore of the liner 2 and is provided with a lower extension I3 having a foot I4 which is gripped 20- between the bottom of a. cylindrical slide I5 and a Washer I6, the latter being pressed against the. bottom of the slide I5 by a spring I1 which reacts against a washer I8 located against a shoulder I9 .in the casing I; the slide I5 is arranged to 25 reciprocate in a guide bore 20 formed in the casing I and the spring I'I serves as a return spring for the plunger I2 which is arranged to be moved in an upward direction by means of a cam acting against the bottom of the slide I5 or against a 30 roller secured thereto, the said cam being of known construction and which it is not necessary to illustrate in the drawing.

The extension I3 of the plunger is provided with a pair of diametrically opposed lugs 2l which 35 extend into slots 22 formed in a sleeve 23 so as to be reciprocable in the said slots axially of the plunger. The sleeve 23 is pivotally mounted around the lower end of the liner 2 and rotation of the sleeve effects rotation of the plunger rela- 40 tively to the liner by means of the lugs 2 I. A split ring 24 is clamped to the upper end of the sleeve 23 by a screw 25 and an arm 26 is provided upon the ring 24 and arranged to extend to the exterior of the pump through an opening 2'I -in the 45 casing I. The control rod or the like for effecting rotation of the sleeve and plunger is arranged to be secured to the arm 26 by means of a bolt 28. The plunger I2 is provided with an axial bore 29 extending from the upper end of the plunger 50 for about half the length thereof and lateral apertures 30 are arranged to establish communication between the lower end of the said bore and an annular recess 3l formed in the cylinder wall of the liner 2 around the plunger. Lateral passages 55 32 are formed in the liner and establish communication between the annulus' 3| and an annular recess v33 formed in the casing I around the liner 2. The annulus 33 is arranged in ccmmunication with an inlet passage 34 formed in a pipe union 35 of a fuel supply pipe 38, the pipe unio1135 being secured to the casing I by a union nut A helical recess 38 is formed in they exterior of the plunger I2 .and is maintained at all times in communication with a discharge space constituted by an annular recess 39 formed in the liner 2 around the plunger I2 and lateral passages 40, Figure 3, are formed in the liner 2 to establish communication between the annulus 39 and an annular recess 4| formed in the casing I around the liner 2. 'I'he annulus 4I is arranged in communication with a spill outlet passage 42 formed in the pipe union 35 and communicating with the supply pipe 36, The upper end of the helical groove 33 is arranged to co-act with a pocket 43 formed in the upper end of the bore of the liner 2 and which is provided with an inclined control edge 44.

In the operation of the pump liquid fuel is admitted from the pipe 36 through the passage 34, annulus 33, passage 32, annulus 3| and passages 30 to the bore 29 in the plunger and thence to the compression space in the cylinder head 5, lso long as the passages 30 are in register with the annulus 3| and the necessary difference of pressure exists between the space in the cylinder head 5 and in the supply pipe 36. During the upward stroke of the plunger, assoon as the passages 30 have moved past the upper edge of the annulus 3|, the liquid fuel in the cylinder is delivered under pressure past thevalve 'I land thence to the fuel injection nozzle arranged to be supplied by the pump, until the upper end of the groove 38 passes the control edge 44 of the pocket 43 when the pressure in the cylinder space instantly drops and fuel is discharged during the remainder of the compression stroke through the groove 30 into the annulus39, thence through the passages 40 to the annulus 4I, passage 42 and back into the suction pipe 36. In the drawing the plunger is shown in a position in which the groove 38 is arranged to by-pass all the fuel during the delivery stroke so that no fuel is delivered past the valve 1. Upon rotation of the plunger, however, in the direction of the arrow a, Figure l, through the medium of the arm 28, the point at which the upper edge of the groove 36 passes the control edge 44 may be arranged to occur at any Point within a predetermined range later in the compression stroke of the plunger, so that the length of the plunger stroke between the moment when the passages 30 are closed by passing beyond the upper edge of the annulus 3| and the moment when the upper edge of the groove 33passes the' control edge 44 determines the amount of the fuel delivered past the delivery valve 'I to the injection nozzle.

lIt will thus be observed that the flow of the fuel into the cylinder space of the pump is effected through suction passages in the pump which are quite distinct from those passages which effect the discharge of the spill from the pump so that the flow of liquid through lthe suction passages is always in the same direction, whilst the pump is also free from the oscillation of liquid which is caused by the provision of a suction valve. Ed-

dies of the liquid in the suction passages. are thus :,oesgseo V completely avoided, as also the production of gas bubbles from the liquid.

The helical arrangement of the groove 38 causes a whirling of the spill in the annulus 30 which tends by centrifugal action to discharge the spill through the passages 40, thus facilitating the discharge of the spill and, producing a suction effect in the cylinder space during such discharge,

whilst the tangential arrangement of the passages 40 with respect to the annulus 4| facilitates the discharge of the spill from the annulus 33 to the annulus 4I in which the fuel is again caused to whirl and so facilitate its discharge through the tangentially arranged passage 42. Damping of the iiow of the spill which is caused by sudden changes and reversals in the direction of flow and absence of adequate discharge spaces, is thus avoided.

It will be observed that the location of the suction annulus 3| at a more remote point from the cylinder head than the annulus 39 for the spill and which is subjected to higher pressure than the suction annulus, serves to prevent leakage of liquid fuel past the plunger I2 in a downward direction, because any liquid leaking from the annulus 30 downwardly is intercepted by the annulus 3|.

In the modification of the invention illustrated in Figure 4, the outlet for the spill from the pump is maintained separate from the fuel supply inlet, the fuel supply pipe 36 being arranged to convey the liquid fuel to the passage 34 leading to the outer suction annulus 33, whilst a discharge pipe 45 is arranged in communication with the outlet passage 42 leading from the outer spill annulus 4|. In this modification it is possible to supply fuel to the pipe 36 under pressure through a primary pump, whilst the pipe 45 may be arranged to discharge the spill directly back into the fuel tank.

' Referring to the modified construction of pump shown in Figure 5, the various parts have been designated by the same reference numerals as in Figures l to 3, where possible, but with the addition of I 00. In this construction, liquid fuel is supplied through an inlet passage |34 to a suction annulus |33 disposed around the cylinder liner |02 and thence through passages |32 directly past the plunger I2 to the cylinder space, the suction ports formed by the passages |30 being uncovered by the plunger at the end of the suction stroke. The spill is discharged through an axial bore |29 'in the plunger and thence through a port |50 formed laterally in the plunger into a pocket |43 sunk in the cylinder wall and the upper portion of which may be in the form of an annulus. The spill leaves the pocket |43 through oneor more passages |40 and passes into an annulus I4I from which it is discharged through an outlet passage |42; preferably, thel port |50 and passages |40 and |42 are tangentially arranged with respect to the annular space or,

spaces I 43 and I 4I for the same reason as that stated with reference to Figures 1 to 3. The p'ocket |43 is provided with a control edge |44 which co-operates with the port |50 to determine the moment at which the spill commences in a similar manner to that of the end of the groove 38 with the control edge 44 above described, the plunger ||2 being rotatable by control means of the same character as that disclosed in Figure 1 and 2. A

What I claim and desire to secure by Letters Patent of the United States iszmunication with an axial bore formed in 'the plunger and opening into Vthe cylinder space, a spill passage formed as a helical groove on the outer surface of the plunger and closed at its upper en d, a pocket in the cylinder wall provided with a control edge inclined relatively to a plane transverse to the cylinder and adapted to cooperate with the closed end of the spill passage during each compression stroke of the plunger to by-pass liquid from the cylinder space, an annular discharge space in the cylinder wall around said -plunger and arranged in direct and constant communication with said spill passage, an outlet passage -for said discharge annulus tangentially disposed relatively thereto for facilitating the dis- Acharge of liquid circulating in the annulus by virtue of the motion imparted thereto by the helical spill passage, and means operable to eiect cylinder.

2. In a liquid fuel injection pump the combination of a cylinder and a plunger reciprocable therein, a suction port in the cylinder Wall, a. lateral passage in the plunger adapted to co-act with said port to control the admission of liquid to the pump, 'said passage being arranged in communication with an axial bore formed in the plunger and opening into the cylinder space, a spill passage formed as Aa helical groove on the outer surface of the plunger and closed at its upper end, a pocket in the cylinder wall provided with a control edge inclined relatively to a plane transverse to the cylinder and adapted to cooperate with the closed end of the spill passage during each compression stroke of the plunger to by-pass liquid from the cylinder space, an annular discharge space in the cylinder wall around said plunger and arranged in direct and contant communication with said spill passage, an outlet passage for said discharge annulus tangentially disposed relatively thereto for facilitating the discharge of liquid circulating in the annulus by virtue of the motion imparted thereto by the helical spill passage, a second discharge annulus concentric with the first and arranged to receive liquid from the first through said outlet passage,

an outlet passage for the second annulus tangenl tially directed thereto for the purpose specified and means operable to eiect relative rotation between the plunger and the cylinder.

3. In a liquid fuel injection -pump the combination of a cylinder and a plunger reciprocable therein, an annular suction space disposed in the cylinder wall, a lateral passage in the plunger arranged to co-act directly with. said annular space to control the: admission of liquid to the pump, said lateral passage being arranged in communication with an axial bore formed in the plunger and opening uninterruptedly into the cylinder space, a spill passage formed as a groove extending axially of the plunger on the outer surface thereof and closed atits vupper end, a pocket in the cylinder wall provided with a control edge inclined relatively to a plane transverse to the cylinder and arranged 'to co-'operate with the closed end of the spill passagelduring each compression stroke of the plunger to by-pass liquid from the cylinder space, an annular dischargespace distinct fromsaid annular suction space and, arranged in direct and constant communication with the spill passage which is disposed at an angle to said annular' discharge space. suchthat the fuel is fed tangentially thereto from the said spill passage, an outlet passage for said annular discharge space, and means operable-to eiect relative rotation between the plunger and the cylinder.

4. In a liquid fuel injection pump the combination of a cylinder and a plunger reciprocable therein, an annularsuction space in the cylinder wall controlled-by theplunger acting as aslide valve, an axial bore in the plunger leading to the cylinder space and having an open end arranged to be brought into communication .with the suc tion space in the cylinder wall at the appropriate time each cycle of operations, a control edge inclined with respect to the longitudinal of the p ger, a discharge passage-entirely separate from said axial bore and comprising a helical groove so arrangedin the surface of the plunger that the spill fuel is caused to flow along said groove helically around the plunger, av fiu'ther discharge passage of annular configura,

tion located in the wall of the cylinder and connected with the helical groove in such a manner that the fuel is fed tangentially thereto from the said groove, an outlet passage for said annular discharge passage, a blind end in the helical groove arranged to co-act with the control edge to by-pass liquid from the cylinder space through the annulardischarge Apassage and the outlet passage and means operable to effect relative rotation between the plunger and cylinder to vary the amount of liquid so by-passed. y

5. In a liquid fuel injection pump the combination of a cylinder and a plunger reciprocable therein, a suction portlin the cylinder wall controlled by the plunger acting as a slide valve, a suction passage comprising an axial bore in the plunger leading to the cylinder space and having an open end arranged to be brought into communication with the suction port in the cylinder Wall at the appropriate time in each cycle of operations, a helically inclined control edge, a discharge passage entirely separate from said suction passage and comprising a helical groove of the same inclination as the helical control edge and arranged to co-act therewith to enable the ready discharge of the liquid from the control edge to the helical groove along which it flows helically around the axis of the cylinder, a further discharge space of annular configuration located in the wall of the cylinder and in constant communication with the said helical groove, the helical control edge and the helical groove being located one on the plunger andthe other on the cylinder and arranged mutually to co-operate during each compression stroke of the plunger to by-pass liquid from the cylinder space through the helical groove to the annular discharge space which it enters tangentially from the helical groove to enable a rapid flow to be obtained, an outlet passagey for said annular discharge space and means operable to effect relative rotation between the plunger and cylinder to vary the amount of liquid so by-passed.

6. In a liquid fuel injection pump the combination of a cylinder and a plunger reciprocable therein, a suction space of annular configuration in the cylinder Wall controlled by the plunger acting as a slide valve, a suction passage comprising an axial bore in the plunger leading to the cylinder space and having an open end adapted to be brought into communication with the suction space in the cylinder Wall at the appropriatev time in each cycle of operations/a control edge inclined with respect to the longitudinal axis of the plunger, a discharge passage entirely separate from said suction passage comprising a helical groove in-the surface of the plunger, a rst discharge space of annular conguration entirely separate from said annularv suction space and located in the wall of the cylinder in constant -communication with the said helical groove, a second discharge space of annular conguration surrounding said rst discharge space and connected with a discharge port leading to the exterior of the pump, an outlet passage connecting said discharge spaces which is disposed tangentiauy to said'nrst discharge space, la'lclind end-A in said helical groove arranged to co-act with the control edge to bypass liquid from the cylinder space to the said rst .discharge space through the helical groove, the liquid being caused to circulatel rapidly in said first discharge space by virtue of the motion imparted thereto by the said helical groove 'and to discharge tangentially therefrom through said outletpassage to the said second discharge space in a freely owing uninterrupted stream, andv

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