US2698541A - Impulse linkage for injection pumps - Google Patents

Description

Jan. 4, 1955 H. M. Fox

IMPULSE LINKAGE F OR INJECTION PUMPS Filed June 9, 1952 w In.

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. H M. FOX

BY Wm-M A TTOPNEVS Jan. 4, 1955 H. M. Fox

IMPuLsE LINKAGE Foa INJECTION PUMPS 4 Sheets-Sheet 2 Filed June 9, 1952 FIGS INVENTOR.

H.M.FOX BY Maf/.1ML WM ATTORNEYS Jan. 4, 1955 H. M. Fox 2,698,541

IMPULSE LINKAGE FOR INJECTION PUMPS Filed June 9, 1952 4 Sheets-Sheet 3 lil l y l MM 1N VUV TOR.

H.M.F0X

BY l ORA/grs Jan. 4, 1955 H. M. Fox 2,698,541

IMPULSE LINKAGE Foa INJECTION PUMPS Filed Juno 9, 1952 4 Sheets-Sheet 4 INVENTOR.

H. M. FOX

Bxl/@MVM A 7" TORNEKS United States Patent TO Il\/IPULSE LINKAGE FOR INJECTION PUMPS Homer M. Fox, Bartlesville, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware Application June 9, 1952, Serial No. 292,526

Claims. (Cl. 74-2) This invention relates to an impulse linkage for injection pumps. ln a more specific aspect it relates to a device for obtaining proper fuel injection when starting a diesel type engine. In another aspect it relates to an impulse linkage for injection fuel pump in a diesel type engine.

ln diesel engines in which fuel is injected at a pressure developed in accordance with the engine speed, considerable difficulty is encountered in starting the engine. The usual starting speed of the crank shaft is very slow and the resulting movement of the pump injector plunger is so slow that sufficient pressure is not developed by the fuel injector on the fuel to be injected into the cylinder to form a properly atomized spray or to penetrate the compressed air within the cylinder. Consequently, the proper vaporization and inter-mingling of the fuel with the compressed air necesssary to result in combustion is not obtained.

The fuel injection system of a diesel engine forces the fuel at high pressure through a spray nozzle into a combustion cylinder containing highly heated air. The fuel injection pump, comprising a plunger slidably arranged in a cylinder, is usually operated olf of the cam shaft of the engine in direct relation with the speed of the engine. An important function of the injector is the measuring and delivering of fuel to the injection fuel nozzle under sufficiently high pressure to force the fuel through the spray nozzle into the compressed air, also under high pressure, in the cylinder with suicient velocity to atomize the fuel. The fuel must be thoroughly atomized as it is projected into the air charge in order to effect uniform distribution of the fuel in the compressed air, so that almost instantaneous ignition of the fuel can take place in the compressed air which has already attained a temperature above that of the fuels ignition point. The combustion occurs through this heat caused by compression of the air charge in the combustion cylinder.

Various mechanisms have been devised to force fuel into a diesel engine cylinder under high pressure when the crank shaft of the engine is being turned slowly as in starting, however, these devices have been unsatisfactory by being too complicated for economic use and because they cannot be built sturdy enough for continued hard usage. It has been general practice in starting a diesel engine, which was too cold to fire, to lift the rocker arm covering plate and to strike the injectors by hand during cranking. This was accomplished by placing the end of a long screw-driver on one injector and then the other, striking each of them two or three times while the starter motor cranked the engine. This would usually start the cold engine in a shortened time but also occupied the time of more than one operator.

ln at least one embodiment of this invention, at least one of the following objects is obtained:

It is an object of this invention to provide an impulse linkage for an injection pump.

It is another object to provide a device for delivering a rapid stroke to an injection pump while the actuating force is operated slowly.

Another object is to provide a device for injecting fuel into a diesel cylinder under high pressure when the crank shaft of the engine is turned slowly.

Another object of this invention is to provide a spring actuating injection pump.

I have now devised a mechanism for injecting fuel into the combustion cylinder of a diesel engine at sufficient pressure so as to be thoroughly atomized and intermingled in the compressed air in the cylinder so that ignition of the fuel readily takes place when the crank shaft is slowly being turned during the starting of the enr"ice gine. I utilize, in addition to the regular fuel injection mechanism of the engine, an auxiliary actuating mechanism which is made effective manually before starting the engine and which remains effective until stable combustion has been secured. This mechanism is also made ineffective manually, but an automatic means can be used.

In the practice of my invention, the charge of liquid fuel for one stroke of the engine is injected nearly instantaneously shortly after the beginning of the stroke of the plunger of the injector, instead of continuously throughout the effective stroke of the plunger as in normal operation of the engine. This sudden force applied to the liquid charge results in a substantial increase in pressure at the fuel nozzle so that the fuel is caused to penetrate substantially to the center of the cylinder in a finely atomized state so as to be substantially uniformly distributed in the compressed air in the cylinder. The source of power for this impulse movement of the injector plunger is provided by a coil spring member in either the linkages to the plunger or an extension of the plunger shaft whereby the power stored in the spring near the end of the stroke is released at the beginning of the stroke of the injector plunger as a sharp impulse to the injector plunger. Thus, during starting of the engine, the total fuel charge for the stroke of the engine is supplied at an increased rate to the fuel nozzle in perfect timing with the cycle of operation of the engine.

Although the mechanism of my invention will be described as attached to the cam-follower of the fuel injector pump shaft, it can be located anywhere in the linkages to the injector pump, for example, the cam-follower or' a push rod operating through a rocker arm activating the shaft of the fuel injector pump.

The invention is lustrated by the accompanying drawing wherein like numerals refer to like elements.

Figure l is a vertical section through the aXis of the fuel injector pump shaft, showing the cam-follower and cam;

Figure 2 is a partial section of the linkage of Figure l rotated Figure 3 is a horizontal section of Figure 1 on the line Figure 4 is a partial section of the linkage immediately after the pin 13 has been removed from step 20;

Fig. 5 is an elevation of the linkage of Figure 4 immediately after the shaft 10 has completed the stroke urged by spring 17;

Figure 6 is a horizontal section of Figure 1 on the line 6 6 taken after pin 13 has been tripped;

Figure 7 is a partial section of an isomeric View of the linkage showing the relationship of the shaft 10, spring 17, pin 13 and the cam-follower 12 with slot 14;

igure 8 is an elevation of a modification of the linkage; an

Figure 9 shows the detail of a modication of the trip mechanism.

in Figure 1 the pump shaft 10 is actuated by cam 11 acting upon cam-follower 12 so as to compress spring 17 and force pin 13, in the shaft 10, against step 20 of slot 14 in cam-follower 12. Cam-follower 12 ts slidably in housing 23 and rotational movement is prevented by guide 32 on the cam-follower which travels in recess 33 of housing 23. Shaft 10 is free to rotate Within camfollower 12 within the limits of slot 14. Vertical movement of shaft 10 is limited by pin 21 to the space between the top of cam-follower 12 and the collar 22 secured to housing 23.

Trip 15 is forced into contact with cam-follower 12 by spring 26 when lever 30 and connecting arm 28 are positioned to allow the spring to exert its force upon trip 15. Pin 13 extends beyond the circumference of cam-follower 12. Trip 15 has a diagonal edge 25 as shown in Figure 2, which contacts pin 13 as cam-follower 12, spring 17 and shaft 10 are raised by cam 11. The diagonal edge 25 of trip 15 forces pin 13 from step 20 and allows spring 17 to force shaft 10 upward until pin 21 contacts collar 22.

ln the operation of the fuel injector, the injector reciprocates in its cylinder in accordance with the motion communicated to cam-follower 12 by means of cam 11 which is securely attached to cam shaft 24 by key 16.

" The force developed by the rotation of cam 11 is transmitted from cam-follower 12 through coil spring 17 to the end of injector shaft 10, which is slidably mounted in a cylindrical section of cam-follower 12. The inner diameter of the cylindrical section of cam-follower 12 is slightly larger than the diameter of injector shaft to permit said shaft to be readily slidable in said cylindrical section. Coil spring 17 is mounted with its longitudinal axis along the center line of injector shaft 10 while slidably engaged in the cylindrical section of cam-follower 12 and with one end of spring 17 seated against the solid end of cam-follower 12 and the other end seated against the end of injector shaft 10. As shown in Figure l, the end of injector shaft 10 may, if desired, be provided with an extended member 18, of round cross-section, which is securely attached to the end of said injector shaft and arranged so as to slidably project into hole 19 drilled along the center line of the solid section of cam-follower 12 to guide injector shaft 10 in its sliding motion in the cylindrical section of cam-follower 12.

The vertical movement of injector shaft 10 in its relation with cam-follower 12 is governed by the action of pin 13 inserted in the end of injector shaft 10 and extending through the two slots 14 in opposite walls of the cylindrical section of cam-follower 12 sufiiciently to permit engagement with trip member 15. As shown in Figure 2, slots 14 are each composed of two longitudinal tracks, of sufficient width to receive pin 13 without binding, with one track of sufficient length to allow the desired sudden upward movement of injector shaft 10 to take place when spring 17 is released from its compressed position and the other track of sufficient length to permit cam 11 to complete its revolution and thereby compress spring 17 to its cocked position. The longitudinal edges of the two slots 14 are not aligned, but are displaced by a distance of at least one diameter of pin 13 so that steps 20 are formed, said steps 20 operating as stops against which pin 13 in injector shaft 10 is held by spring 17 in its compressed position.

The coil spring 17 is of the compression type with dimensions which will permit it to operate without binding action against the inner surface of the cylindrical section of cam-follower 12 or the outer surface of extended member 18 of injector shaft 10. The constants of spring 17 are such that when the spring is compressed during injection of the fuel in the normal operation of the engine, the spring has sufiicient power to produce the sudden increase in fuel pressure necessary in starting the engine, and also such that the spring can be againcompressed by the engine after the power stored in its has been released. The spring should be strong enough to overcome the resistance of the fuel injection pump during normal engine operation.

In normal operation of the engine, injector shaft 10 is firmly held in association with cam-follower 12 by the force exerted by compressed spring 17 on the end of injector shaft 10 so as to maintain pin 13 against steps 20 in slots 14 because the spring has more than sufficient force to overcome the resistance of the fuel injection pump. The rotation of cam 11 on cam shaft 24 moves cam-follower 12 and injector shaft 10 a distance equal to the stroke of the injector plunger, said distance being defined by the location of pin 21 in injector shaft 10 and its engagement with collar 22 attached to housing 23. There is no compression of the spring 17 as the revolution of cam 11 is completed because pin 21 engages the recessed portion of collar 22 and thus pin 13 is not released from the restraining action of steps 20.

If it is desired that a rigid linkage be provided between cam 11 and injector shaft during normal engine operation, a wedge or similar restraining device can be employed between pin 21 and the top of cam-follower 12 after the tripping mechanism has been rendered inoperative.

In starting, whenever the trip member forces pin 13 from behind steps 20 in slots 14 through the. slight rotation of injector shaft 10, such rotation being possible either through the slidable mounting of the injector plunger in the cylinder or through the use of ball-insocket joints when a push rod and rocker arm mechanism is used, the power of compressed spring 17 is suddenly released and injector shaft 10 is forcefully driven forward in slidable association with cam-follower 12 to instantaneously inject fuel into the engine cylinder in perfect timing with the engine compression. Injector shaft 10 is driven forward either until pin 21 in injector shaft 10 engages collar 22 attached to housing 23, or until pin 13 in injector shaft 10 reaches the end of slots 14 in cam-follower 12. As cam-follower 12 continues its motion in accordance with the action of cam 11 in the completion of the revolution of crank shaft 24, spring 17 is compressed against the end of injector shaft 10 which is rigidly held stationary by the force exerted on collar 22 through pin 21. The spring 17 is at least sufficiently compressed in this manner to permit pin 13 to be reseated behind steps 20 of slots 14; however, depending upon the exact design of cam 11 spring 17 may be compressed more than is necessary for reseating of pin 13, in which case, spring 17 simply expands, after cam 11 has revolved on around, to seat pin 13 against steps 20. With the next revolution of cam 11, pin 13 is again ready to be unseated by trip member 15 so that spring 17 can exert an instantaneous force on the end of injector shaft 10 to inject fuel into the cylinder in a more suitable manner for starting the engine. These instantaneous injections of fuel continue in perfect timing with each cycle of operation of the engine until the engine is started and trip member 15 is prevented from unseating pin 13 from behind steps 20.

The mechanism provided for unseating pin 13 from behind steps 20 is a trip member 15 adjustably attached to the inside of the housing 23 as shown in Figure l. The location of trip member 15 is such that when said trip member is extended in an operative position and slidably engaged with the outer surface of cam-follower 12, the end of said trip member slidably in contact with said cam-follower is just resting on pin 13 of injector shaft 10 as the driving motion of the plunger is begun by the action of cam 11 on the mechanism. The driving motion of injector shaft 10 at the beginning of the stroke of the injector plunger causes pin 13 to be slidably engaged with the diagonal edge 25 of trip member 15, as shown in Figure 3, and thereby pushed from behind steps 20 of slots 14 with slight rotation of injector shaft 10, wherein the force in compressed spring 17 is suddenly released and injector shaft 1l] sharply driven forward. As cam 11 completes its revolution, trip member 15 remains slidably engaged with cam-follower 12, due to the force applied against said trip member 15 by the compression spring 26 securely attached to the housing 23. The trip member 15 remains in this extended position until it is manually removed.

Various methods can be devised for controlling the position of trip member 15 and one arrangement is shown in Figures l and 3. In this design, the end of trip member 15, not engaged with pin 13, is pivotally attached to housing 23 so that said trip member may be positioned (rotated) against housing 23 out of contact with pin 13 and cam-follower 12. Trip member 15 is provided with a slot 27 through which an arm 2S extends and is slidably engaged with said trip member by the pin 29 inserted in the end of arm 23. The other end of arm 28 is rigidly connected with a lever 30 and pivotally attached to a housing section 31 so that upon rotation of lever 30, pin 29 of arm 28 engages trip member 15 in slot 27 and forces trip member 15 against housing 23 out of contact with pin 13 and cam-follower 12. Rotation of lever 30 in the opposite direction ,permits trip member 15 to be engaged with pin 13 and camfollower 12 by release of the power stored in spring 26. In this manner, trip member 15 may be actuated, before starting of the engine, for releasing spring 17 to instantaneously inject fuel into the cylinder during each cycle of the engine and then be removed from association with pin 13 and cam-follower 12 after combustion has been accomplished.

Another modification of the trip mechanism is shown in Figure 8 wherein a sleeve member 41 surrounds the cam-follower 12 and is secured to collar 22 which is rotatably secured to the housing. In this modification, cam-follower 12 is prevented from rotating as in the embodiment of Figure l. The lower end of sleeve 41 has opposite openings 42 of sufiicient width to accommodate the passage of pin 13 in both tracks of slot 14. The trip member 43, having a diagonal lower edge, is pivotally attached to the side of-opening 42 and is urged against cam-follower 12 by spring 44. The inner surface of the upper edge of trip member 43 is beveled so that the trip member is raised by pin 13 when pin 13 is traveling downwardly after spring 17 has been compressed and pin 13 is seated upon step 20.

The trip mechanism is made ineffective by rotating sleeve 41 to the left until trip member 43 is out of alignment with pin 13.

In Figure 9 is shown a modification of the trip mechanism of Figure 1. In this modification trip A is forced into contact with cam-follower 12 by spring 26A when the tension on spring 46 is released and conversely, trip member 15A is removed from contact with camfollower 12 and pin 13 when handle 30A is pulled to its outwardrnost position and the tension of spring 46 overcomes the compression of spring 26A.

Although this device has been described in connection with a diesel engine, it can be employed advantageously in other installations. For example, the impulse linkage of this device can be employed in a chemical injection pump employed to inject small quantities of emulsion resolving chemical into a crude oil pipe line. This device can also be employed for injecting antifreeze material into a high pressure gas line to prevent formation of hydrates. Other uses of the impulse linkage are within the scope of this invention.

Variations and modifications are possible within the scope of the disclosure of this invention, the essence of which is that there has been devised a linkage wherein energy stored in a coil spring is released to impart a sudden forward movement of the forward end of said linkagle when the entire linkage is moved slowly forward.

I c aim:

1. An impulse linkage comprising a housing member; a cam member within said housing, secured to a cam shaft extending through said housing; a cam-follower engaging said cam, slidably supported by said housing and secured from rotation by a rib engaging a groove in said housing; a shaft member slidably passing through an opening in said housing and being slidably secured in an open end of said cam-follower opposite said cam by a pin, passed transversely through said shaft, which extends through and engages slots in said cam-follower, each of said slots comprising a continuous track comprising two sections off-set at least one track width, the section nearest said cam connected to said section farthest from said cam by a track section whose edge nearest said cam comprises a section of a helix extending away from said cam and the other edge of which forms a transverse step; a compression resilient member extending between said shaft and said cam-follower so as to press said pin against said step; and a trip member movably secured to said housing and having a beveled edge contacting said pin when said cam moves toward its extended position, said bevel extending in the same genr eral direction as said helix section.

2. The linkage of claim l wherein said trip member comprises a sleeve member slidably surrounding said camfollower, one end of said sleeve being rotatably connected to said housing and the other end of said sleeve having said beveled edge contacting said pin and an adjoining longitudinally disposed slot wherein said pin can travel when said beveled edge removes said pin from said step.

3. The linkage of claim l wherein said trip member is hinged at one end to said housing and has in combination therewith a spring member forcing said beveled edge against said cam-follower in line with said pin; and a link connected to said trip and extending through said housing for removing said trip member from contact with said cam-follower and said pin against the tension of said SIJ4 gThe linkage of claim 1 wherein said trip member is hinged at one end to said housing and has in combination therewith a rst spring member forcing said beveled edge against said cam-follower in line with said pin; a second spring member opposing said iirst spring member; and a link connected to said trip and extending through said housing for positioning said trip member against the tension of the second spring and the compression of the rst spring.

5. In an internal combustion engine a device for 1njecting an atomized charge of fuel into a cylinder under pressure when the crank shaft is slowly rotated which comprises in combination a housing member; a cam member within said housing secured to a cam shaft; a camfollower engaging said cam; said cam-follower having an opening in the end opposite said cam so as to slidably receive a shaft adapted to be connected to a fuel injector; said shaft being free to move longitudinally within said cam-follower within limits determined by a transverse pin through said shaft which travels in a longitudinal slot in said cam-follower; said longitudinal slot comprising two tracks off-set at least the diameter of said pin, and a corinecting track whose edge nearest said cam comprises a section of a helix extending away from said track nearest said cam to said other offset track, and whose other edge forms a transverse step; a compression resilient member extending between said shaft and said cam-follower so as to press said pin against said step; and a trip member movably secured to said housing and having a beveled edge contacting said pin when said cam moves toward its extended position, said bevel extending in the same general direction as said section of said helix.

6. The combination of claim 5 wherein said trip member comprises a sleeve member slidably surrounding said cam-follower, one end of said sleeve being rotatably connected to said housing and the other end of said sleeve having said beveled edge contacting said pin and an adjoining longitudinally disposed slot wherein said pin can travel when said beveled edge removes said pin from said step.

7. The combination of claim 5 wherein said trip member is hinged at one end to said housing and has in combination therewith a spring member forcing said beveled edge against said cam-follower in line with said pin; and a link connected to said trip and extending through said housing for removing said trip member from contact with said cam-follower and said pin against the compression of said spring.

8. The combination of claim 5 wherein said trip member is hinged at one end to said housing and has in combination therewith a first spring member forcing said beveled edge against said cam-follower in line with said pin; a second spring member opposing said rst spring member; and a link connected to said trip and extending through said housing for positioning said trip member against the tension of the second spring and the compression of the first spring.

9. An impulse linkage comprising a support member; a cam member secured to a cam shaft rotatably attached to said support; a cam-follower; a shaft member slidably secured in an open end of said cam-follower by a projection on said shaft which extends through and engages a longitudinal slot in said cam-follower, said slot having a transverse step intermediate its two ends; a compression spring within the open end of said cam-follower surrounding the lower end of said shaft so as to press said projection against said step; and a trip member movably secured to said support and having a beveled edge contacting said projection when said cam moves toward its extended position so as to remove said projection from said step and to allow said projection to travel in said slot.

l0. An impulse linkage comprising a support means; an open ended driven means slidably secured to said support means; means for longitudinally moving said driven means; a shaft slidably secured in said open end of said driven means by a projection of said shaft which extends through and engages a longitudinal slot, having a transverse step intermediate its two ends, in said driven means; means adapted so as to act upon said shaft so as to force said projection against said step; and means secured to said support and adapted so as to remove said projection from said step and to allow said projection to travel in said slot when said driven means is longitudinally moved by said driving means.

References Cited in the file of this patent UNITED STATES PATENTS

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