US2285730A - Fuel injection pump - Google Patents

Description

' June 9, w42.

C.A.UNDEMAN,JR

FUEL INJECTION PUMP 2 sheets-sheet 2 Filed Deo. 16, 1940 A INVENTOR.- CM@ d g/fm J? ATTORNEY.

BMM MAMA/M Patented June 9, 1942 a amato FUEL mJEo'rroN omnes A. maman, Jr., (nimo, nl. Application December 16, 1940, Serial No. 370,289

(Cl. B-4l) 14 Claims.

This invention relates in general to a high pressure pump for a periodic discharge of small `measured quantities of \fiuid, particularly in in- .ternal combustion engines. This invention relates particularly to fuel pumps of the positively actuated plunger type with a suitable by-pass controlled by a valve and having important novel`l objects and advantages, among which are; to provide a leakage return from the nozzle valve spring chamber which prevents pressure from building up and restricting the opening of the injection valve; to permit -use of the pump and nozzle in upright or inverted vposition withoutv making material changes in the structure; to provide a by-passvalve which produces a very sharp ending of injection to stop dribbling; to avoid the formation of a vacuum in the plunger chamber as fuel is allowed to enter when the plunger is retracted by the spring, and therefore no air is taken in lalong the plunger; in providing a pintle in the spring nozzle which prevents clearance when the valve is closed, thus `squeezing out fuel and preventing carbon from forming in the nozzle; to provide means for easily testing the 'nozzle injection pressure; in providing an injection pump with a variable beginning and a xed ending, a fixed beginning and a variable ending, or a' variable beginning land a variable ending, without making any material changes in the pump structure; and in general to provide the structure herein shown and described.

Other objects of the invention will appear in the'speciflcation and will be apparent from the accompanying drawings in which:

Fig. l is a cross sectional view illustrating an injection pump mechanism in accordance with this invention;

' the time of opening of the by-pass valve.

Fig. 1A illustrates a modification of the struc- 4 ture of Fig. 1;

- Fig. 2 is an enlarged cross sectional view taken on the line 2-2 of Fig. l;

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 2;

Fig. d is a sectional view taken on the line v t-t of Fig. i:

Fig. 5 is a sectional kview 5 5 of Fig. 2; and l Fig. 6 is a view taken on the line 6-6 of Fig. 2.

In this inventions. by-pass valve separate from the pump chamber is connected to permit bypass of fuel from the Vpump chamber and is separately and adjustably operated by means of a connection with the pump operating rocker arm so that an easily accessible external control means is provided which is adjustable for controlling the beginning and ending of varying the stroke of the pump.

Referring now more particularly to the drawings. a pump plunger III is slidably mounted in one end of a close iitting plunger barreill, the

taken on 'l the line injection without other end o! the Ibarrel being threaded into a reduced bore in a pump casing I2, the bore being continued to provide a plunger compression chamber Il. A plunger spring I4 surrounds the plunger and the plunger barrel and is seated at one end against a flange I5 projecting outwardly from thebarrel and at they other endagainst flanged head I8 at the end of the plunger. The

pump plunger is freely movable in a bore I1 provided in a projection I8 of the pump casing;

and al plunger tappet guide 20 is threaded into the outer end thereof. A plunger tappet 2l. is inserted through the guide to engage the pump plunger head I6 at its inner end and is engaged at its outer end by a tappet roller 22 mounted at one end o f a pump rocker arm 2l; The rocker armis pivoted intermediate its ends upon a rocker shaft 24 and has a rocker arm push rod 25 connected at the other end of the arm for reciprocating the pump plunger periodically against the action of the plunger spring I4.

Mounted in ay recess in the upper end of .the projection I8 is a rod` 9 adjustably held by a set screw 8 and having graduations Iv disposed adjacent the tappet 2| to measure and indicate the positionof the pump plunger yin relation to Extending from the plunger chamber I3 in the pump casing I2 is a high pressure fuel passage 28 which leads to the lower end of the casing where it communicateswith an annular space 21 between the pump casing'and an injection valve barrel 28 having a lapped joint therewith atthe end of the casing. An injection valve casing 29 is threaded on the reduced end of the casing I2 and holds the barrel 28 tightly at the'lapped joint. At the outer end of the casing 29-` is a reduced opening through which an injection valve seat plug 30 projects, the upper end of. the valve seat having a flange 3l of the same external y diameter as the injection valve barrel 28 so that. when the' injection valve casing 29 is threaded tightly upon the end of the casing I2, the injection valve barrel 28 and the injection valve seat plug 30 are held tightly in place against the'end of the pump casing I2 with the extremity of the valve seat projecting from the injection valve casing.

Opening from the end of the4 casing I2 is a` -spring recess 32 for containing an injection valve spring 33. Slidably mounted in the bore of the l injection valve barrel 28 is an injection spray valve 34 with an inner valve pintle v35 having a pointed extremity which nts tightly in and extends entirely through an opening 36 in the injection valve plug 30. The upper end of the pintle is threaded and has anvadjustment nut 31 forming a pintle lock which holds it in place.

with respect to the valve 34 because of the engagement of the lower end of the valve spring 33 with the locking nut 31.

At the lower end of the valve 34, it is seated upon a tapered seat 36 closely surrounding the plntle 35 at the top of the valve seat piece 30. Extending upwardly from the valve surface is a concave groove 39 which together with a similar opposite groove 40 at the adjacent inner and lower edge of the valve barrel 26 form an annular high compression space 4I connected tothe annular space 21 at the top of the valve barrel by inclined passages 42 in the barrel.

Pressure is applied by the pump plunger 2|, from chamber I 3 through passage 26. space 21, passages 42 to the compression space 4I. When this pressure is suiiicient, injection valve 34 and its attached pintle 35 are raised against the pressure of spring 33 thereby injecting fuel through the opening 36 in the injection val`ve piece 30.

'I'he pump casing I2 and the valve casing 26 as a unit, are inserted tightly in an opening 43 in a cylinder head 44 of an internal combustion engine which is of considerable thickness to provide space 45 for a waterjacket at the outer vend of the cylinder head and has a reduced bore or opening 46 at the bottom to receive the reduced end of the injection valve seat plug 36.

At one side of the pump plunger bore I1 and relatively at right angles thereto in the casing `I2 is a high pressure bore and space 46 having a closing plug 56 at one end and a by-pass valve assembly at the other end. This assembly comprises a by-pass valve 6I with along threaded stem, a valve seat 52 therefor threaded in the end of a guide 53 which in turn is threaded in the end of the bore 49 to hold it tightly in 'place` Slidably in the guide is a valve and tappet holder 54 into which the stem of the valve 5I is threaded, the extremity of the stem projecting beyond the outer end of the holder and having a lock nut 55 adjustable thereon. Adjacent the outer end of the holder is a flange 56 and at a distance from the outer end of the guide 53, is a flange 51 with a valve spring 56 disposed between The low pressure chamber 56 is connected to the plunger bore I1 by openings 10 through the wall of the by-pass valve guide 53 which communicates with a surrounding groove 1I in the outer wall of the guide and thence through a transverse passage 12, closed at its outer end .by a screw 13, leading directly into the pump plunger bore.

At the opposite side of the pump casing I2 is a relief or outlet passage 14 connected to the upper end `of the spring recess 32 with closing s tud15 at the outer end. A transverse relief passage 'I6 extends in the casing I2 from the pump plunger bore I1 which intersects the passage 14 and is provided with terminal fittings 11 for a'leakage return pipe 16 by which any leakage or by-passed fuel or liquid is returned to a fuel supply tank.

Leakage fuel or liquid will ordinarily fill the spring recess 32, outlet passage 14 and pump plunger bore .I1 to thelevel of the relief passage 16. Injorder toprevent such liquid from escaping along the stem of tappet 2l, the inner end of the guide 26 is reduced in size at its inner end to provide a relief space around it communicating with the relief passage 16. To prevent pumping of liquid from this space by movement of the tappet, the inner edge of the guide -opening `19 is beveled with openings 60 extending through the wall o'f' the guide at the upper or inner edge of the bevel. When the inner end of the tappet 2l is engaged by the ilat flanged head I6, any entrapped liquid will be driven up the beveled edge 19 and discharge out of the openings 60 instead of following along the tappet stem.

To supplyy fuel for the pump plunger in the plunger chamber I3, an inclined passage 6I leads downwardly vfrom the top of the casing I2 which is counter-bored at. its outer end to provide a seat for a spring 62 which presses a check valve the two flanges and tending to lclose thevalve 5I on its seat 52.

At one side of the by-pass valve 5I is the high pressure chamber 49, and on the opposite side is a low pressure chamber 59, the valve controlling communication therebetween. 'The high pressure chamber is connected to the plunger chamber I3 by a passage49 extending from the high pressure chamber to a check valve chamber 60 at an angle thereto with a passage 6I from the botl Atom ofthe check valve chamber whichextends into a passage 62, extending laterally from the plunger chamber I3.

Closing the top of the check valve chamber is a stud 63 and engaging a seat 64 at the bottom of this chamber is a valve 65 having an upwardly extending stem and a spring 66 engaging the valve surrounding the stem and bearing against the inner end of the stud at the other end of the chamber. This check valve opens at a pressure slightly higher than the pressure of Va fuel transfer pump which delivers fuel. from an outer source of supply to the pump and prevents a free iiow of fuel when the by-pass valve is open. Also connected to the passage 6I is a transverse passage 61 communicating with a Agroove 66 at the outer side of the plunger barrel II and having one or more openings 66 through the plunger barrel preferably at or adjacent the top of the stroke of the pump plunger I0.

63 against an opening in a-stud 64 at the end of a fitting 65 to which an inlet pipe 66 is connected at the outside of the casing. This check valve admits fuel to the pump upon its suction stroke but is immediately closed by its spring 62 whenever apy pressure is applied by the pump plunger I6 .I'hus fuel is admitted to the plunger chamber when the plunger is raised by means of its spring I4, and when the plunger is depressed by the action of rocker arm 23, the fuel is compressed below the plunger in thechamber I3 and in all of the passages connected thereto, the high pressure passage'26 and through the pressure'check valve 65 to thehigh pressurechamber 46. When the by-pass valve 5I is closed, the pressure produced by the pump plunger I6 will be sufficient to raise the injection valve plunger 34, injecting a small quantity of fluid under high pressure through the needle valve opening 36 of the injection valve plug 30. When the by-pass valve 5I is open, a sumciently high pressure will not be built up to open the injection valve 34 against its spring 33 andthe fuel will then be delivered through the by-pass passages and the return pipe 16 to a suitable fuel supply reservoir. 'I'he closing plug 56 is supplied for conveniencer at the end of the high compression chamber 46 as a bleeding plug and also for-conveniently applying a pressure testing unit to determine the pressure produced'by the pump in the high pressure chamber and connected passages. Manipu; lating the pump rocker arm 23 with this plug 56 removed will bleed the unit.

To actuate the by-pass valve. a tappet 61 is threaded on the end of the holder 56 for the inside locking nut 5 5, but havingits own lock nut Blf. This tappet is engaged by a contact roller 88V at one end of a rocker arm 89 pivoted intermediateits ends upon an eccentric 90. The

eccentric is secured to a shaft 9| mounted in a bearing in an upward projection 92, attached as a separate piece vas shown in Fig. 1, or forming a part of and integralwith the cylinder casing i2', as shown by Fig. 1A. The shaft 9| also has an arm 98 secured thereto for rotating the shaft and thus changing or adjusting the'eccentric 90. For a plurality of cylinders, this shaft may be continuous and common jto all of them.

At the other end of the try-pass rocker arm 3 and may be accurately located and adjusted for varying and positioning the parts mounted thereon. In attaching and applyingy the parts,

v the rounded shoulder |05 acts as a hinge for is a contact roller 94 adapted to engage a cam 95 which has a split adjustment portion 98` for variably mounting it upon la hub 'projection .91 of the rocker arm 28. Formed on the cam 95 are projections 98 and 99, adapted to be engaged by the roller 94 as the rockerarmis actuated by its push rod 25. When the roller 9B is at the outer ends of the projections, the opposite end of the by-pass rocker arm 89 pushes the tappet 81 inwardly, opening the by-pass valve 5|, and when the roller rests in the space between the projections or on the other outer portions of the cam, the opposite end of the cam is moved outwardly with respect to the tappet, al-

lowing the spring 5 8 to close the by-passvalve. l,Thus the length of the stroke remains substan4 tially the same, although the cam engagement may be varied to change the time of fuel injection. v To make the pump inoperative, it is necessary only to keep the valve open, and this may be accomplished by a.lever |00 mounted in the flange 81 on a bearing pin |0| and having an eccentric v|02 moved thereby into engagement with the adjacent end of the by-pass rocker arm 80. This holds the rocker arm and the valve inits openposition where it is unaected by the cam projections. A spring |03 connected at one end to theby-pass rocker arm, and at 'the other end to a fixed projection lijd, secured as a bent rocker arm 23 into which the end of a sharp instrument such as. a screw driver or other suitable tool is inserted. By rocking this arm, and adjusting the by-pass valve tappet 8l, the duration of injection can be accurately adjusted to coincide with other similar units of the engine. The position of the tappet 2| with 'respect to the graduated rod 9 at the time the by-pass valve tappet roller 94 is just making contact with the cam lobes 98 and 99 thus determines the duration of injection.

All adjustments for the purpose of synchronizing the metering of the units should be made at the by-pass tappets Si. y

Adjustments of the different pump 'and injection units should be made with the eccentric adjustment levers 93 in a fixed position for all units. If' the adjustment eccentrics 9@ are all mounted on a common shaft 9i, they maybe the cam 95 and by varying the eccentric mounting of the by-pass rocker arm. By varying this engagement with the projections of the cam, the injection pump may have a variable beginning and a xed endng'pressure, a fixed beginning and a variable ending, ora variable beginning washer under the head of. a bolt 48, tends to keep the end of the arm in engagement with the tappet 81, but the by-pass valvespring' 58 overcomes this spring |03 for closing thevalve.

In applying the combined pump and injector to the opening 43 of a combusti-on engine cylinder, a flange 41 projects from the pump casing I2 having an opening therethrough through which a fastening bolt d8 is inserted. At the side opposite the flange is a rounded shoulder |05 adapted to be engaged by an overlying shoulder |06 as an extension of the mounting projection 92 if it is separate from the cylinder as shown in Fig. 1. In/this case, an opening |01 is provided for another bolt 48 which is inserted therethrough and into a suitable threaded opening |08 in the cylinder head. In the' construction as shown by Fig. 1A, a clamping block |09 is substituted for the corresponding extension of the projection 92 in Fig. 1, and the pump and injection unit are therefore tightly held in place by the bolts at the opposite sides thereof.

In orderl to accurately adjust and set the projection 92 as shown in Fig. 1, the outer 'edge thereof may have a set screw ||0 inserted tact with the upper face of the ange. By po-v sitioning the set screw as desired, the shafts 9| and a variable ending without making any material changes except in 'this' adjustment. In practice, the injection valve spring 33 has a xed or known compression which must be overcome in order to provide for the injection of fuel at a predetermined pressure and this pressure may be determined Without removing or disconnecting any part except to attach a pressure gauge in place of the plug 50 at the end of the high pressure chamber. In this type of injector, no vacuum is formed in the pump barrel or passages, thus preventing air from being taken intol the pump and causing faulty injection.

I claim:

vl. A fluid pump comprising a casing, a pump plunger movable therein, a high pressure de- .livery outlet for the pump, a spring pressed de- 2. A fluid pump according to claim 1 in which A the relief passage is at an angle to the movement of the pump plunger, and said actuating means comprises a rocker arm, an adjustable double lobed cam movable with the rocker arm and a lever engaged by the ca mfor opening the relief valve.

3. A uid pump according to claim 1 in which the relief valveis closed by` a spring, the actuating means comprises a rocker arm, a cam movable with the rocker arm having high `points points, and the cam being adjustable to vary the position of the high points, and a lever, engaging -the cam at one end and engaging the relief valve at the other end to open the relief valve at the high points of the cam against the tension of the valve spring, the valve being closed by the spring at the said low points of the cam.

4. In a fluid pump comprising a casing, a pump plunger movable therein, atappet projecting from the casing for moving the pump, means for actuating the tappet to operate the pump, a graduated gauge supported adjustable in the casing adjacent the projecting end of the tappet independent of the actuating means and having the graduations to indicate the length of stroke of the tappet of the pump.

5. A fluid pump comprising a casing, a pump plunger movable therein, a high pressure delivery outlet for the pump, a spring pressed delivery valve for the outlet opened by high pressure fluid from the pump, a by-vpass relief for the pump including a valve in a passage in the casing connected to the high pressure side of the pump, a rocker arm for actuating the pump, a cam movable with the rocker arm `having alternate high and low portions, a lever engaging the cam at one end and the relief valve at the other, a spring tending to keep the relief valve closed and the lever in contact with the cam, and an eccentric bearing intermediate the ends of the lever.

6. The combination with a pump structure according to claim of a manually operable device for engaging the valve operating end of the lever and holding it and the valve inwardly against the pressure of the valve spring to prevent operation of the lever by its cam and to hold the relief valve open.

7. In a fluid pump, a pump plunger, a casing having a spring chamber for the pump plunger and a high pressure discharge chamber, a high pressure delivery outlet for the pum'p, a by-pass relief for the pump including a valve in a passage in the casing at one side of the pump chainber, leakage return passages in the casing connected to the pump spring chamber and vto the by-pass relief passage, a tappet extending into the pump `spring chamber for actuating the pump plunger, and a mounting extending into the chamber and having a bore for the tappet having relief means at 'the inner end thereof passages in the wall of the casing for high pres- `sure fluid from the pump chamber to the delivery necting with the by-pass relief passage at the` other side of the valve, means for operating the pump, and means for positively operating the relief valve at the beginning and ending of fuel injection to control the duration and discharge of high pressure fluid from the high pressure delivery outlet for the pump. s

10. A structure in accordance with claim 9 in which the high pressure delivery valve has a spring chamber in the casing and a .passage in the wall of the casing from the spring chamber to the relief side of the by-pass relief passage so that the entire leakage from the by-pass and from the pump 'casing will have a common outlet.

l1. In a fluid pump, a casing, a pump plunger movable therein, a high pressure delivery outlet for the pump at one end of the casing, means for actuating the pump at the other end of the casing. an intermediate flange projecting fromthe casing, a by-pass relief for the pump includingA a valve in a passage transverse to the pump plunger in the flange of the casing, means adjustable on the pump actuating means for actuating the valve in timed relation to the pump operation, and means for engaging said flange to hold the pump in discharging position and the valve and its actuating means in fixed relation to the pump.

12. A uid fuel pump for an internal combustion engine in accordance with claim 11 having the pump and the relief valve in a common casing in which the delivery outlet of the casing is inserted in an opening in the engine cylinder, a fastening bolt inserted through the pump flange at one side of the casing, a shouldered projection on the flange 'at the other side of the casing, and a fastening means including an extension to overlie and engage said shouldered projection of the casing for additionally holding it in place'.

13. A fluid pump structure in accordance with claim l1 in which the by-pass relief forvthe pump withinV the pump spring chamber, the `pump plunger with the end of the mounting.

8. In a fluid pump, the combination with a casing, a pump plunger movable therein, a high pressure delivery outlet for the pump, a by-pass relief for. the pump including a valve in a passage in the casing, a rocker arm for operating the pump plunger, a cam carried by the rocker arm, a lever engaging the cam for operating the relief valve and means forming a socket at the outer side of the rocker arm for receiving a tool inserted therein for manually reciprocating the rocker arm to bleed fluid from the pump casing.

9. In a fluidpump, a casing, a pump plunger movable therein, a high vpressure chamber and a high pressure delivery outlet for the pump, a spring pressed delivery valve for the outlet and is located in a passage in the flange transverse to the pump plunger, the stem of the valve projecting from one end of the relief passage and the other end of the passage being closed by a removable stud to which connection can be made forv measuring ,the pressure of' fluid therein and determining the operation of the pump.

14. A fluid pump comprising a casing, a pump plunger movable therein, a high pressure delivery outlet for the pump at one end of the casing, means for operating the pump plunger at the other end of the casing, a projecting flange intermediate,the ends of the casing by which it is secured in place, a by-pass relief for the pump including a valve in a passage in the flange of said casing at right angles to the pump plunger, the valve having an operating stem projecting from the flange, a cam actuated by the pump operating means, a lever engaging the cam at one end and engaging the relief valve lat the other end, means for adjusting the lever to control the opening operation of the valve, and an adjustable tappet at the end of the valve stemlfor varying. its engagement with the lever.

CHARLES A. LINDEMAN, J R.

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