US1654938A - Fuel pump - Google Patents

Description

Jan. 3, 1928. 1,654,938

' F. LANG FUEL PUMP 6 Original Filed June 22, 1923 2 Sheets-Sheet l g}! i v 5, v

I I MI 1/10 E J I i I Patented Jan. 3, 1928.

PATENT oFFIcE.

rnanz LANG, or unmcmcammr.

FUEL PUMP.

Original application filed June 22, 1923', Serial No. 647,001, and in Germany October 14, 1921. Divided and this application filed January 12, 1925. Serial No. 1,939.

The present improvements relate to pumps for delivering liquid fuel to an atomizing nozzle or device, and have, among various uses, an important application to internal combustion englne-s of the compression-ignition type.

This is a division of my copending application known as Serial No. 647,001, filed June 22, 1923, on internal combustion engines, to which reference is made for a disclosure of the application of these improvements to a compression-ignition engine having many notable advantages. -Another division of said copending application is filed concurrently herewith as Serial No. 1,940 on the improvements in atomizing devices in the first-mentioned application set forth, and to which reference may be had.

The chief object of the present improvements is to increase efiiciency both in the pump mechanism as a unit and in the engine or other fuel-consuming device as a whole. It is an object to obtain such resultsthrough a device of simple, strong and durable construction. It is an important object also to provide in a pump construction of the character described simple and highly advantageous means for easily regulating or controlling the amount of fuel delivered on each pumping stroke whereby the speed of the engine or other results depending upon the amount of fuel consumed may be readily controlled. Other objects and advantages will appear hereinafter.

In the accompanying drawings, which form a part of this specification, Figure 1 shows my improved pump device in vertical section, as on the line 1-'-1 of either Fig. 2 or Fig. 3; Figs. 2, 3 and 4 are cross-sectional views on the lines 2-2, 3-3 and 4-4 respectively of Fig. 1; Figs. 5 and 6 are vertical sections on the lines 55 and 6-6 respectively of Fig. 1; Fig. 7 shows the cams side by side; and Fig. 8 is a vertical section showing nozzle parts more fully illustrated in in said copending applications. These drawings are substant ally to scale. Figs. 1 to 6 show the partsabout one-third smaller than as used in the pump associated with the engine illustrated in my said first-mentioned .copending application, while Fig. 8. shows nozzle parts on the scale actually used in the nozzle for that engine.

Referring to Fig. 1 there is providedfirst a; body- 115 formed of steel, the shape of which is well shown in the several figures. This body is bored to provide a fuel reservoir 116 (Fig. 6) the upper end of which is closed by a threaded plug 117 havin an air pocket 118 o ening into the receptacle or chamber 116. he fuel enters through the opening 119 which is in direct communication with the fuel supply pipe 120 (Fig. 2), to be understood as leading to a reservoir, not shown. When starting the fuel flow an objectionable amount of air may become entrapped in the chamber 116 and this may be permitted to escape by a slight retraction of the conical screw 122, which is then tightened. The body of air above the level of the screw 122 serves as a cushion for the incoming fuel.

Adjacent to the oil reservoir 116 there is provided fuel-'ntake and fuel-control valve mechanism (see Fig. 6). 'The construction comprises a cylindrical valve seat body 123 having a conical seat against which rests a conical valve 124 having a stem 125 provided with longitudinal grooves or recesses in communication with the channel 126 leading to the oil reservoir. The stem 125 has secured at its lower end a piston 127 reciprocable in a cylindrical re'cesscontaining a coiled spring 128 which maintains the valve 124 geldingly in closed position. The valve ody 123 is recessed above the valve at 130 to provide for upward movement of the valveand from this recess 130 a channel 131 (see also Fig. 1) leads to the piston chamber of the pump. The valve seat body 123 is held in position by a shouldered plug 132 which is pressed upon by the screw plug 133. The threaded hole 134 in .theiplug 133 is merely to permit a threaded member to be inserted there for withdrawing the plug 132 should occasion require.

The cylindrical and tubular member 135 is provided with a disc-like flange 136 by which it is secured by screws 137 to the lower end of the body 115. I The tubular cylinder 135 is co-axial with the valve stem 125 and ored and threaded to accommodate the lower portion of Fig. 1 it will appear that the lower end of the metallic sleeve or housing 135 is bifurcated at 142 to provide clearance and relative movement for the roller 143 traveling on the cam 139'keyed to the engine shaft 18. This roller 143 is mounted in the lower end 138 of the cylindrical member 138, this part 138 being bifurcated to accommodate the roller 143, the pin 144 passing through the roller and the part 138 and extending outward on each side as shown in Fig. 1, the extending ends of the pin 144 being flattened at 144 (see Fig. 6), which flattened parts are guided in slots 145, Fig. 6, in the lower end of the member 135. It will thus be clear that the roller 143 is held against turning movements relative to the sleeve-like member 135, but that it may move upward relative thereto, and also that since it is mounted on the member 138 that member will move up and down within the member 135 when the roller so moves, and that, since the screw shaft 140 is carried by the member 138, the screw shaft, and also the pinion 141, will move correspondingly up and down.

A coiled spring 146 presses against the pinion 141 and maintains the roller 143 constantly in engagement. with the cam 139. A relatively wide rack 147 is held (see Fig. 1) for sliding movement in engagement with the pinion 141 within a recess cut into the main body 115, a rack-holding member 148 held by screws upon the body being adapted to maintain the rack in position.

' It will be clear that when the rack 147 is moved longitudinally the resulting rotation of the screw shaft 140 will increase or decrease the distance between the end of the projection 140 at the top of the screw shaft and the lowermost cross-line of the roller 143, and that consequently the gap illustrated between the projection 140 and the valve piston 127 may be increased or decreased or reduced to nothing, and that the projection 140 may be raised to such an extent with respect to the lowest possible position of the roller 143, that the valve 124 will be maintained open.

It will be noted that the cam 139 has a relatively high place at 150 and that this high surface merges into a long, gradually lowering surface which reaches its lowest place at about 153 where the lifting part of the cam begins. As the engine shaft 18 rotates in the clockwise direction it is evident that the roller 143 will rise when the enlargement of the cam strikes the roller, maintain its osition for approximately threefourths of the cam revolution, and then descend with a gradual movement until about the time the pump piston begins its abrupt upward movement, at which time the roller 143 begins a more rapid descent for closing the valve 124. It is also clear that according to the adjustment of the screw thread 140 bymeans of the rack 147 the valve 124 may become seated with the roller 143 at various places on the descending part of the cam, or, as stated, the screw shaft may be raised to such an extent that the valve will remain open even when the roller is on the cam at its lowest surface 153.

The rack 147 may be moved by hand for such purposes, or may be connected up with any approved means for shifting the same by the operator at a distance, as for instance in automobiles.

I will next describe the associated pump mechanism, and will then further explain the action of the fuel-control valve.

The pump elements are contained chiefly in a boring or borings parallel to the fuel valve device described. The fuel discharge pipe 92 is to be understood as leading to the atomizing device opening into the engine cylinder, as to the device of Fig. 8. It is secured as by sweating it to a sleeve-like fitting 175 having an enlargement 176 and held in position by the packin gland 177. The fitting 175176 is axially ored to accommodate the materially long compression spring 178 which delivers pressure upon a collared pin 179 seated loosely in a recess in the top of the discharge valve 180. This valve 180 has a longitudinal recess 181 along the cylindrical side thereof through which fuel passes into the space 182 above the valve and thence into the discharge pipe 92. The valve-seat member 183 is of cylindrical construction having the enlargement 183 resting upon a shoulder formedin the main body 115. This seat member 183 has a conical seat with which the valve 180 int'erfits. The valve seat member 183 has an integral cylindrically tubular part 183 which extends downward and constitutes the piston cyl-- inder of the pump. The main body 115 is cylindrically bored from the bottom with a relatively large diameter at 185 and a piston 186 fits with a very nice mechanical fit into the wall of cylinder 185. The pum piston 187 fits with a'nice mechanical fit t roughout its length within the pump cylinder 183", and at its bottom it is provided with an enlarged cylindrical head 188 which rests upon a saddle member 189 carried loosely and fitting upon the circular back 190 of a device which carries the roller 191 on a shaft 192. From Fig. 1 it will be noted that the downward extension 189 of the saddle 189 projects downward between bifurcations of the member 190 and thus the saddle 189 is held against lateral movement. While loosely positioned it cannot get out of its proper position during the operation of the device since its top surface 193 is flat and rests against the flat bottom surface of.

the piston 186, and since the spring 195 seated in the space 185 constantly presses the piston 186 against the saddle 189 and maintains the surface at 193 horizontal. The roller 191 is mounted on a link arm 1% pivoted at 197 to a fixed support 111, (Fig. 5). When the roller 191 is moving up and down the saddle 189 slides on its circular seat but cannot move out of its position because of the pressure with which the flat surfaces at 193 are maintained together.

The cam 200 on the engine shaft 18 is provided with a relatively high surface at 201.

The distance from the surface at 202 to the high surface at 201 is materially short whereby when the engine shaft ismoving in the clockwise directlon the roller 191 is raised suddenly, or through a relatively few degrees of the engine shaft revolution. The high place at 201 merges fairly sharply into a ower surface at 203 and thence the cam surface gradually lowers to a place at 204,

, whence it rises gradually'to place 202. The

rise in the cam from 204 to 202 is about oneand-one-half millimeters in the cam actually used on the engine illustrated in my said copending application Serial No. 647 001.

The lower enlargement or head 188 of the pump piston is provided with a pair of oppositely-disposed small recesses 205 which communicate with the piston chamber or space 185 and these vents 205 provide for the .escape of-air when thepiston 186 is moved inward, and also permit oil which has leaked between the piston 187 and cylinder 183 to escape and also to lubricate the parts/below. The operation of the pump is as follows: From the position of the cam shown in Fig. 5 the high surface 201 of the cam first moves the roller 191 and with it the piston 186 and also the pumppiston 187 sharply upward. This upward movement is say about six millimeters in the construction shown, but this movement taken with the movement provided by the cam surface from 204 to 202 displaces considerably more fuel than is reuiredfor the particular engine with which t e pump is used, meaning thereby that the capacity of the pump is greater than the maximum charge required by the engine.

The liquid displaced is that which was drawn into the upper end .184 of the piston cylinder. On the upward movement of the piston 187 the upper end thereof may contact the valve stem 180 lifting the valve 180 from its seat, or the valve 180 maybe forced the movement of the liquid, and the liquid passes through the channels 181 and be understood that'on the upstroke of the ump piston all of the passageways for fuel,

eadmg. from the pump through the pipe 92 to the discharge orifice 66 of the nozzle are filled withdiquid and that pressure applied to the liqu d in the pump is communicated,

through this body of liquid in the fuel line, to that relatively small body of fuel which on each particular pump stroke becomes atomized at the nozzle.

After the high place 201 on the cam 200 has passed the bottom line of the roller 191 there occurs first, as noted, a sharp or sudden drop of the piston through the provision of the low cam surface at 203, the effect of which is to relieve the pressure in the fuel line and permit the valve at the orifice 66 (Fig. 8) to close, and substantially instantaneously therewith to retract, or suck back slightly, fuel in the fuel line and to such an extent that at the nozzle discharge orifice 66" under the roller. This low point at 204 is just about 180 degrees from the high place at 201. From this surface at 204, since the cam rises very slightly and very gradually from 204 to 202, the pump piston is moved upward that slight distanceduring almost half of the revolution.- This preliminary slight upward movement of the piston has the effect of changing gradually or reversing the liquid flow entering the upper end of the pump piston, and gradually forces some of the'excess liquid in the pump cylinder back through the passageways leading to' the reservoir 116. The liquid has thus been gradually put into movement and some excess liquid discharged before the sudden and-powerful movement of it provided by the relatively short cam surface leading upward from place 202 to place 201. 1

The combined or sequential action of the pump and fuel-controlling valve mechanisms may now further be described.

Let us assume that the pump piston 187 is moving upward and discharging a supply of liquid fuel. Throughout the first part of the upward stroke fuel is being returned to the reservoir 116 through the valve 124 which is being held open through the action of the cam 139 and the adjustments made by the rack 147. The time during which the valve 124 is maintained open and the amount of the valve opening are varied by the operator according to the amount of fuel which it is desired to discharge into the fuel line, or, in other words, according to the amount 'of fuel desired to be atomized on the particular pump piston stroke. The valve 124 is maintained open for a longer time when I the engine is on light load or idling, thus permitting a greater quantity of the fuel to escape back to the reservoir 116.

Let us next assume that the pump piston is started on its downward stroke through the action of the spring 195. Fuel is now drawn into the upper part of the piston cylinder and reaches that place by passing through channel 126, valve 124 and channel 131, the valve 124 having been opened by the cam elevation at 150 almost, but not quite, as soon as the piston began to descend. This small delay in the opening of valve 124 is will be understood that when the valve 124 is opened it may remain open during a large part or all of the cam revolution. When the engine 1s normally running under fuel the valve 124 does not remain open all of the time, but when it is desired to stop the engine the rack 147 is moved to cause the valve 124 to remain open, in which casethe fuel drawn from the reservoir .116 on one suctlon movement is returned thereto on the ensuing pressure stroke, this line of travel ofl'ering much less resistance than the fuel.

line. Consequently no atomization takes place and the engine stops.-

It is evident that if the rack 147 were so moved as to keep the valve 124 open during a. relatively large-part of the pump piston stroke a relatively large part of the discharge fromthe pump cylinder would flow back to the re;ervoir 116, and that only a relatively small part thereof would be advancedin the fuel line,'and this is the condition when the engine is on light load or idling. The fuel is injected into the fuel line at some later movement as distinguished from the initial movement of the pump piston power stroke. According to the load the valve 124 will close, by adjustment of the rack 147, earlier or later. It is when the valve 124 doses that the injection of the fuel takes place. This injection may be for merely an instant, starting when the roller 191 is almost at the top of the high place 201 of the cam. It may be for a longer period, starting when the roller is half-way up the inclined cam' surface or elsewhere thereon. But whatever the length of the effective fuel-advancing stroke, it begins with the closing of theplve 124, and thereupon the great power 0 the pump piston applied in a very short space of time is communicated through a solid body of the fuel in the fuel line to that relatively small portion of fuel immediately at the nozzle opening.

meter, these dimensions being such as are employed by me in the engine in my said first-mentioned copending application described. Such an exceedingly -minute passageway at the spray point provides an exceedingly high resistance to the flow of fuel at the outlet 66. It is adistinct feature of the present pump construction thatit delivers a very high pressure upon the fuel in the fuel line, and in a very brief space of time, which pressure is sustained to the end of the power stroke of the pump piston, whereby the desired exceedingly fine atomization is continued through the effective piston stroke.

The pump piston stroke is substantially long. The same amount of fuel could be displaced, of course, with a piston of larger diameter and shorter stroke,'but in the application of these improvements. to engines, as set forth in my said first-mentioned copending application, the amount of fuel oil passing through the nozzle at a given instant in its exceedingly finev state of subdivision is relatively small, and for the various engine loads up to full load the Injection must be continued for such a time as will. provide in the engine cylinder the req- According to the injection-control means shown, the shifting of the rack 147 moves the threaded member 140 to increase or decrease the efi'ective length of the expansible element comprising the members .138 and 140 and thus determines at what relative position of the pump piston on its power stroke that stroke becomes effective to force fuel into the fuel line, and thus controls the quantity of fuel injected on a given stroke, all in the desired exceedingly fine state of subdivision.

The conditions here present...are to be dis-' tinguished from those in which the fuel in the fuel line leading to the nozzle is given a sudden initial impact by the pump piston, which impact causes the valve at the nozzle to open. We have here a condition in which a pump piston with a substantially long fuel until a predetermined instant toward the end of the stroke when the escape passage is closed, at which instant the full power of the piston is applied to the fuel in the fuel line, and this fuel-advancing power is then sustained until the end of the pumping stroke.

It isimportant, of course, that the cams 139 and 200 on the engine shaft be so positioned with respect to the engine piston movements that the atomized discharge into the compression side of the engine cylinder takes place at the proper time. I prefer to inject the fuel when the compression in the cylinder is approximately that required for ignition. for adjusting the cams to regulate the timing of the discharge, as such means may constitute subject matter for an additional ap plication, and the same is not essential to the operation of the device illustrated and described herein.

I contemplate as being included in the invention or improvements herein set forth such changes, modifications and departures from what is herein specifically illustrated and described as fall within the scope of the appended claims.

I claim:

1. In an internal combustion engine, means for fuel injection comprising in combination pump means adapted to pump on each pumping strokethereof more than the maximum. amount of fuel required on each engine power stroke when running at full load, valve means in the path of the fuel from the pump adapted to open to admit therethrough suflicient fuel required on each engine power stroke for the heavier engine loads, including full load, with means for maintaining said valve open during a small amount of, initial return movement of the pump piston, and mechanically-operated valve means in communication with the suction side of the pump adapted to open to admit fuel to the suction side of the cylinder after the small initial return movement of the piston. V

2. In a fuel pump for an internal combustion engine the combination of walls forming a cylinder, conduit-forming means extendin from the compression side thereof, a piston in said cylinder, valve means in said conduit timed with the' return movement pf the piston tf val of time after the piston has begun its return movement, and hand-regulable mechanically-operated valve means ada ted to open a passageway to admit fuel to e suca'lso adapted to close I have not shown herein means lose said conduit against the" return of liquid therethrough a short inter-.

tion side of the piston at'about the time said timed valve means close said conduit, and

the piston has started on a power stroke and before it has completed that power stroke.

3. In a fuel pump of the character described, the combination of walls forming a. pump and-escape conduit in communication with the suction side thereof, a piston on said cylinder, means for givin the piston a power stroke, a valve in sai including a pair of threaded members in threaded engagement with each other for communicating motion to said valve in one for movmg said direction, cam means threaded members longitudinally in timed relation to the piston power stroke, said threaded members constituting an extensible element intermediate said valve and said :cam means, the arrangement being such that said valve is moved in one direction earlier or later with respect to a given piston stroke according to the relative adjustment of said threaded members, and means operable by hand for axially turning one of said threaded members relative to the other thereof.

4. In a fuel pump of the character described, fuel-control means including in com.- bination a fuel-escape valve, continuously operated means for closing and opening said valve intermittently, said last-mentioned means having a valve-operating movement greater. than that required for normally op-' erating the valve and some of said movement being lost motion not communicated tothe valve, said continuously-operated means including a pair of threaded members forming a longitudinally expansible element whose effective length determines the extent of such lost motion, and rack-and-pinion means for turning one of said threaded members relative to the other for varying the amount of such lost motion to vary the operation of said valve. i

5. In a fuel pump of the character described, the combination of walls forming a cylinder, a piston therein, means providing a supply-and-escape passageway for excess fuel in communication with the suction side of said cylinder, a valve for'opening and closing said passageway, means ncluding a cam for moving said piston with a power stroke, said cam having a surface adapted to move said piston with a relatively slow movement in the power-stroke direction during .a materially long part of the power stroke movement and having a surface adapted to move the piston at a relatively high rate of travel at the end portion of the power stroke movement, means including a adapted to maintain said valve open during said passageway after I cylinder, means forming a supply conduit, means tions of the piston power stroke movement, means for operating said cams, handregulable means for varying the time of closing of sald valve relative to plston power stroke movements, means forming a dis-' charge conduit extending from the compression side of said cylinder, a valve in said discharge conduit adapted to open under pressure of the fuel in the pump, and means for maintaining said last-mentioned valve open a short interval of time after the piston has started on its return movement.

. FRANZ LANG.

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