US1080216A - Fuel-pump for internal-combustion engines. - Google Patents

Description

A. HQ'HOADLEY. V FUEL PUMP FOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED DEC. 22, 1911. 4 1,080,216. v Patented Dec. 2, 191 3.

2 SHEETSSHEET 1.

W/TNESSES: INVENTOR ATTORNEY.

A. H. HOADLEY. FUEL PUMP FOR INTERNAL COMBUSTION ENGINES;

APPLICATION FILED DEC. 22, 1911;

Patented Dec. 2, 1913.

2 SHEETSSHEET 2 W t w o? m A m Arm!) n. noanmr, or rnovrnnnca-nnone ISLAND.

FUEL-PUMP FOB INTERNAL-COMBUSTION ENGINES.

Specification of Letters Patent;

Patented cc. 2, i913.

Application filed December 22, 1911. Serial No. 687,281.

To all whom it may concern:

Be it knownthat I, ALFRED H. HOADLEY,

a citizen of the United States, residing at pressure superior to the pressure of compression. This may be accomplished by the pump injecting the liquid fuel directly into the compressed charge of air in the combustion cyllnder, or into an auxiliary charge of air of superior pressure, which in turn injects the mixture of fuel and air into the cylinder. It is this class of pump to which my invention more particularly applies, the object of my invention being primarily, to improve upon the apparatus heretoforedn use for this purpose, and to provide a simple and eflicient mechanism, comprising a combination of members, organized forgpperating with practical economy in expense and cost of maintenance. Also, to attain a bet-- ter operation and results, and an improvement in the means of governing the speed of the engine through the operatlon of the improved pump.

My invention pertains more es ecia lly to multiple-pumps, although some eatures of my improvementsmay be applied to pumps used to serve a single-cylinder engine.

Engines of the type named have heretofore, 1n some instances, been regulated in speed by varying the amount of the liquid fuel injected into the cylinder at each working stroke. The totalamount of the fuel is always relatively small, while the variation in amount, due to small changes in load, is extremely small. Itis therefore desirable that the pump should becap'able'of a positive and variable delivery of minute amounts, and against relatively heavy pressures. It

I would seem that a properly designed heavypnes'su-re pum having a variable-stroke plunger, varia le from zero to maximum stroke by the action of a governor, would accomplish this end; but such a pump has .'been found, in practice, to fail to deliver reliably at the shorter ranges of its'stroke. The most successful type of pump for this service is one having a constant, maximumstroke plunger with a variable by-pass which shunts a portion of the pump delivery back into the suction pipe and closing the pass at that point in the stroke which represents the required delivery due to the remainder of the stroke. One application of the above named by-pass principle is to use the suction-valve as a by-pass, employing in connection with the valve, means controlled by the governor for holding the valve open during a part of the delivery stroke, whereby the fuel will flow back into the suction pipe instead of being delivered against a superior pressure, until the suction-valve closes whereuponthe delivery due to any uncoma pleted portion of the delivery stroke of the plunger, will take place. My invention applies equally Well to pumps having either the delivery by-pass or the suction-valve variable closing system.

Heretofore, for multi-cylinder engines, it

has been customary to employ a completepump for each cylinder; that is, having a separate plunger, connections and operating details, for every cylinder, in order to insure positive and unvarying results. VVhlle such practice is efl'ective as to results, it becomes expensive in engines of two or three cyl nders, while in case of four, six or eight cylinders, (or even more as promise to obtain in marine units,) the cost becomes excessive, especially in high-pressure engines where the umps must deliver against a; ressure of Eve hundred pounds or more. y invention provides a simplified construction and novel mechanism, requiring but one pump to supply two or more cylinders, the single ump being timed as to speed to give a de ivery stroke of the plunger for each firing ,stroke of each cylinder; and combined with the pump casing'is a system of delivery passages and valves, one for each cylinder. These valves are controlled and timed in operating so as to deliver the pump discharge in required quantity to the proper one of the several cvlinders at the proper time. An essential element in the combination is a bypass valve, which can-.be arranged for operating in either of the ways above mentioned.

" thereto determined by the number of cylinone by-pass will su ce; whereas heretofore suction-valve; but it will be-understood that view of the same taken on the line A B, and in a plane at right angles to Fig. 1. Fig.

engine-shaft at a speed ratio to the shaft 7 that severally permit discharge into secondary passages or spaces 8; each opening liquid tot e cylinders. (Not herein shown.)

To serve sa four 0 lindersione um and a separate and complete pump and complete by-pass devices were required for each and every cylinder.

To illustrate the nature of my invention, I have shown, in the accompanying drawing, an embodiment thereof adapted to serve a three-cylinder engine, and a form wherein the by-pass function is performed by the my invention is applicable for any other number of cylinders, and is equally Well illustrated by the drawings as the proper elements for any additional number of cylinders would be combined and arranged to operate substantially like those here shown.

I do not limit myself to the exact details or to the precise arrangement of parts as shown; the illustration being typical in character, and various modificatlons can be made from the form shown and still embody my invention.

In the drawings, Figure 1 is a partly sectional elevation view showing the elements which are essential to my invention, together with such other parts as will pertain to a complete working pump of the character claimed. Fig. 2 is a fragmentary sectional 3 is a horizontal sect-ion at line X on Fig. 1, and Fig. 4 is an end view of the slidable regulating cam whereby governor control is transmitted to valving means. Fig. 5 is a sectional detail view at line Y Y, of one of the check valve fittings for the cylinder ducts or delivering passages, and Fig. 6 is a fragmentary section showing a modification in the by-pass means.

In the construction shown the numeral 1 indicates arotatable shaft, serving as the motor shaft for the parts shown, and which in practice is driven by connection with the 'which must bear a certain speed relation dots in the engine. An eccentric 2 fixed upon shaft 1 is connected to operate the reciprocating pump-plunger 3. This works in the (pump chamber 4 within the casing or body ofthe pump, and into which a suc-v tlon passage 5 debouches, and out of which a delivery passage 6 leads. Said passage 6 is provided with exits or delivery openings 7 being controlled by a delivery valve 9. There must be a separate exit assage for each engine cylinder to be servedfeach passage being independent of the others beyond the delivery controllin valve. Leading out of the exits or secon ary passages 8 are ducts or 'ipes 10, which deliver the fuel one-third the speed. It may ratus and communicate with the secondary passages 8 by means of fittings 11, which are adapted to very high ressure, in this instance, and each contains a double checkvalve device 80, of a proved kind, to prevent return of any of the fuel liquid after entering the duct.

The delivery valves 9 have stems 90, and are individually opened by cams 12 carried on the shaft 13. In the present instance the valves are assistedin closing by springs 14. The cam-shaft 13 may be driven from the shaft 1 by spur gears 15 and 16, or otherwise. The manner of driving is unimportant so long as the rotation is positive and the speed-ratio correct. This ratio must be as the number of cylinders is to one revolution of shaft- 1, in this case three to one. The series of cams 12, 12, 12, are designed and arranged to. time in succession, corresponding with an entire delivery stroke of the plunger 3. It will therefore be understood that with the aforesaid speed ratio, three successive delivery strokes of the pump will discharge fuel successively into the three cylinders, as determined by the series of controlling cams 12, 'ving in the engine the same effect as to time and charges as would three individual pumps, 0 crating at e further noted that in any instance the speed of the single pump must be such as to give one revolution of the plunger-driving shaft 1 to each firing stroke of the engine.-

My improved governing means consists of the combination of parts shown at the right-hand end of Fig. 1. Upon the shaft 1 is mounted a slidable cam 17 which is caused to rotate with the shaft by a spline 1 and is actuated by endwise movement 0 en one delivery at a to open period of each from the engine governor G through any ber 91, that is moved by fluctuations of the governor element; which latter can be of any approved kind. The fuel, from a suitable source of supply, is delivered by H.'

In this in- Y .nected by the link 19 with a lever, or mem-' pipe 20 into asecondary chamber 21 and 4 from there it passes in'tothe suction passage 5 through the opening 22 controlled by the suction-valve 23, (Fig. 1) which valve is carried upon a stem 23 arranged through a suitable packing-gland and guide bearing, and is best provided with a roller 24 at 1ts end, against which the cam 17 acts.

The

cam 17 is so formed that for one-half of its revolution it does not'lift the suction-valve at all, which is free to act in a normal manno lifting is pump-plunger. The other half of the cam is formed to effect a variable lift action on the suction-valve during the delivery stroke of the pump, by its protuberant portion 71 acting upon the roller 24 in t e end of the suction valve-stem. When the cam' is at one, end of its sliding stroke with the small end under the roller 24', iven to the suction-valve by said cam uring the deliver stroke of the pum plunger 3. Hence t e entire volume of ischarge for that stroke of the pump must go to one or the other of the cylinders. ,On the other hand, when the cam is at the other end of its slide-stroke with the large end of the cam beneath the roller 24, then the suction-valve will be lifted and held open during the entire discharge stroke of the pump, thus serving as a by-pa ss and consequently the fluid will all be pushed back into the suction pipe on account of the lesser pressure in that direction, and there will be no discharge'whatever to either cylinder. In any intermediate position of the cam 17 there will be a corresponding part of the delivery-stroke, during'which the suction-valve will be held open and a part of the discharge will go back into the suction- .pipe; while, upon the closing of thesuctionvalve 23, that part of the discharge due to the remaining portion of the plunger stroke, will be forced into one or the other of the cylinders. Thus it will be seen that the suction-valve opens freely to admit the suction of fuel into the pumping chamber;-but its closing action is mechanically regulated by the position of the cam 17 which is determined by the governor (Jr. Hence the regulation of the quantity of fuel that is sent to a cylinder is very accurately adjusted to the requirements. for a properly proportioned charge. This same mechanism will work equally well if applied to a separate by-pass, or by-pass-valve for the pump discharge, an example of' which is illustrated in Fig. 6, wherein a separate or special by-pass conduit 33 is provided and the controlled valve 34 is arranged in said special conduit; the valve stem 34* being actuated by the cam 17. A valve closing spring 36, having atension power superior to the suction force exerted on the valve, is best combined with the valve stem, as indicated. If desired; this by-pass can be connected with the discharge side of the pump and lead back to the supply pipe 20, the operatingefi'ect being practically the same as above explained. In this modification there must bean independent suction-valve 32 in addition to the byass valve 34, and aseparate passage from t e suction pipe must be provided therefor. x

I do not claim broadly, aduating the discharge of. a pump, either y the suctionvalve method or the by-pass method; my invention and claim havin reference to a particular way or manner 0 operating a by-pass or a suction-valve whereby increased sensitiveness of governing is obtained, a more eilicient action of the fuel supplying means secured; and the regulation of speed and action of the engine is im roved. In my mechanism the cam 17, which has onl one valve to operate, is subjected to practically no longitudinal thrust from the resistance of lifting the valve, what little thrust there may be, not 'being enough to overcome the sliding friction of the cam on the shaft, consequently the resistance to be overcome by the governor is only this sliding friction, which is very small and which is also a constant resistance. During from one half to about nine tenths, of a revolution of the cam, practically no Work is being done on the roller 24 by the cam. Hence the governor has this time to shift the cam practically without any resistance, and without any disturbance when the cam lifts the valve, whatever degree of pressure the valve may have to open against. The result is that the governing of the discharge will be as close as the governor is capable of producing, and untra-mmeled by undue and variable disturbances.

The effect of my herein described improvements and of their application to an internal combustion engine, is to equalize the intensity of the firing and enhance the efliciencyin the regulation whereby smoothness of operation is attained and wear and tear is reduced, which advantages are additional to the reduction in the original cost of construction of the fuel pumping mechanism, as hereinbefore set forth.

I claim- 1. In an apparatus for supplyingliquid fuel to the cylinders of an internal combustionengine, the combination of a unitary pump having a primal discharge chamber with a plurality of exits, operated deliveryvalves including an independently acting valve for each of said exits, a freely operable mechanically controlled suction valve, means comprising a positively driven cam-shaft with a series of cams thereon disposed to severally operate said delivery valves, and means for varying the closing action of said suction valve working, synchronously with the pump.-

2. In an apparatus for supplying liquid fuel to the cylinders of an internal combustion engine, the combination of a single plunger pump having a plurality of delivery exit passages, individual conduits therefrom for the respective cylinders, aseries of independently movable valves for the deliveryexit passages, mechanically actuated .means for operating said deliverywalves, a bypass valve controlling a by-pass located between the supply conduit and pum -chamsuction valve, and means for operatin said by-pass valve, for the purpose specific 3. In a fuel pump for internal combustion engines, the combination, of a pump body including a passage, and a de ivery passage, a pumpmg plunger working in said pumpchamber, a plurality of separate valve-controlled openings into underlying secondary passages that communicate by a separate feed-duct with the engine cylinders, a controlling puppet-valve for each of said openings into the secondary passages, said valves having end- -wise reciprocating stems at the exterior of the casing, and means comprising a rotatin cam-shaft with a series of cams carrie thereon, for individually operating said valves. V

4. In mechanism for forcing liquid fuel into cylinders of multi-cylindrical internal combustion engines, the combination of a pump body including a pump-chamber having a suction-passage and discharge-passage connected therewith, a supply conduit with a port opening into said suction passage, a plurality of exit ports opening from said discharge passage, with secondary passages and fittings for attaching the several cylinder supply pipes, individual valves for the respective inlet and exit ports, each having a projecting stem, a single pumping element working in said pump chamber, a rotating shaft having means for reciprocating the pumping element, a supplemental shaft having means for individually opening said exitvalves, gearing operating said supplemental shaft at a speed ratio as the number of exit valves is to one stroke of the pump, an endwise movable cam acting against the stem of said inlet valve,. and means for varying the relative position of said cam in accordance with the speed of rotation of the motorshaft.

5. In a fuel-supply mechanism for multicylinder internal combustion engines, the

ump-chamber, a suction combination of a pump casing including a chamber having a laterally extended area provided with a plurality of valve-seated egress openings and secondary separate chambers beneath said openings, a pumping element adapted for working therein with itsstrokes synchronous with the firing intervals of the series of cylinders-,-means for actuating said pumping element, an ingress passage to said chamber, a plurality of separately actuated egress valves, ducts for taking the discharge from the individual second- 'ary chambers to the respective engine cylinders, said ducts provided with automaticaLly act-ing check-valves, a rotating shaft actuated by positive gearing in conjunction with the actuating means for the pumping discharge passages, each provided with an independently acting closing valve having a projecting valve stem, individual conduits from said discharge passages for connecting the respective engine cylinders, said conduits having means for preventing back ward flow therein, a revoluble cam shaft carrying a series of cams that individually actuate said discharge-valves in sequence, means for rotating said cam shaft at a speed ratio greater than pumping impulses.

Witness my hand this 20th day of December, 1911.

, ALFRED H. HOADLEY.

Witnesses:

GEORGE P. MACREADY, WILLIAM E. WHITE.

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