US2333895A - Liquid injection apparatus - Google Patents

Description

Nov. 9, 1943. M. J. SMITH 2,333,395

LIQUID INJECTIOli APPARATUS Filed Dec. 16, 1959 2 Sheets Sheet 1 lNVTENTOR M EFPTON J, SMITH.

BY Mr m.

A TTORNE'Y Nov. 9, 1943. M. J. SMITH LIQUID INIECTION APPARATUS 2 Sheets-Shee1i 2 Filed Dec. 16, 1939 Y INVENTOR. MEPTON 7. SMITH. $6.1M. c444 ATTORNEY .rstnmd tleaa, 1943.

UNITED STATES PATENT oer-Icamquin mmc'rroN arrana'rus Merton J. Smith, Cleveland, Ohio, asslgnor, by direct and mesne assignments, of twenty-five percent .to Paul 18. Shannon, Chicago, Ill., twenty-flve'per cent to John Perry Geiger, Cleveland, Ohio, and twenty-five per cent to Robert W. WilsomBocky River, Ohio Application December 16, mp, Serial No. 309,623 4 Claims. (01. 277-20) This application is a continuation in part of This invention pertains to-the field of liquid supply,'a nd is intended for the purpose of supplying charges of. liquid through a delivery duct in such a manner that a cut-ofl of the supply in the duct at a point removed from the delivery orifice willresult in an instant cessation of delivery, without any dribbling after cut-oil occurs, and this. without any closing means at or immediately adjacent the delivery orifice. The invenmy co-pending application, Se'rialNo. 196,999, filed March 19, 1938, now Patent No. 2,183,875, granted December 19, 1939.

fltion is herein illustrdedand described with respect to use in connection with internal combustion engines, particularly of the Diesel and semi- Diesel type, although uses in other iields, or for liquids other than liquid fuel, arewithin the scope of the invention. Besides 'true Diesel. engines, the invention finds a usefulness for engines of the type in which gaseous fuel such as natural gas'or blast furnace gas, .is the primary fuel,'and the charge is fired by an injection of a small quantity of liquid fuel.

T'he features of the invention include means for feeding small discrete quantitisof liquid fuel to a point. of use by successive impulses, with cessation of supply between the impulses. One inventive feature in the accomplishment of this purpose is a? simple means, with no moving parts, for preventing dribbling at thedelivery point between supply impulses. Other features are an arrangement of loading a valve for snap-action against constant heavy pressure, and an arrange- -ment of such valve with respect both to the dur a' tion of valve opening and the lead or lag of valve openin in the en ine cycle actuating element. I

Another aim of this invention is the-provision of means to utilize a single distributor in the high pressure systemto supply fuel to a plurality of points of use, with no valves beyond the distributor, thus, among other advantages, greatly by a single valvesimplifying the fuel supply mechanism of Diesel and similar engines, and enabling a-single piece of simple self-contained apparatus, resembling -the electrical. distributor of a gasoline e e and connected to each cylinder only by a single tube, to be used for all the cylinders, with no moving parts at the points of delivery. This feature may the engine cylinder, or other destination. 'One example of another destination is a burner, if the principles of my invention are applied to deliver fuel for heat instead of for power.

' Further aims are the provision of fuel supply means for internal combustion engines as indicated above which are light and quick-acting,

whereby, in conjunction with other features of the invention, it becomes possible to increase the speed of Diesel and similar engines to those on the order of gasoline engine speeds, thus opening the way to diminishing the size and weight per horse-power, giving greater operating flexibility, and other desirable results. v

To the accomplishment of, the foregoing and related ends, said invention, then, consists of the means hereinafter ,fully described and particularly pointed out in the claims;

The annexed drawings and the following description set forth in detail certain mechanism embodying the invention, such disclosed means constituting, however, but one of various me-% chanical forms in which the principle of the invention may be used. 4

In thev accompanying drawings Fig. 1 is a general layout in diagrammatic plan view, illustrating the invention applied to a fourcylinder engine; I a Fig. 2 is a vertical central section through a preferred form of distributor and a preferred formof nozzle, with their connections, with some parts in elevation, on the plane 2-! of Fig. 3;

Fig. 3 is a plan view of Fig. 2; F 4 is a valve detail from Fig. 2, on a larger scale and modified in some particulars;

.Fig. 5 is an enlarged elevation of a detail taken generally as indicated by the arrows 5, 5, Fig. 2,

be more particularizedas means of liquid .fuel

supply under constant ultimate pressure to a dis-- tribution point, distribution from that point into capillary tubes momentarily connected at proper times to the supply means, and by such tubes to with the housing removed, illustrating a preferred adjustable valve arm mounting;

Fig. 6 is a plan view indicated by the arrows from the distributor through capillary feed tubes 7 '4 to'nozzles 5 in engine cylinders 6. In accordance with the usual practice, there is a surge bottle I on the line I. Usual arrangements are provided to regulate pressure, such as a'by-pass per arm Diesel practice, on the order of thousands of' pounds per square inch, but the tube walls are not unduly thick, since it is not objectionable if they stretch slightly, supplementing the efiect of the surge bottle 1. All parts may be connected by high pressure fittings of conventional type.

The supply tube leads into a chamber II in the head I2 of the distributor 3, from which valves l control flow into the distributor tubes 4. On account of the high pressures encountered, the distributor head l2 may preferably be'I'ormed of a single block of metal in which various bores are drilled and parts milled away for the appropriat interior ahd exterior parts and attachmerits. The entire distributor also includes a housing 8 in which the head I2 is seated and in the-lower part of which an upper. timer shaft 9A revolves in suitable bearings, as shown, and as described in detail hereafter.

The chamber II, in the preferred form shown, comprises a central axial bore, preferably about th diameter of the supply tube I, and a reduction bushing ||A therein, the orifice MB of which is smaller than the passages 4A, hereafter described. From the chamber passages l3 (best shown in Fig. 4) connect with valve chambers l4. Such orifices and valve chambers are preferably disposed with their axes on a common plane perpendicular to the axis of the chamber Hand connecting with near its bottom. The eflect of the reduced orifice B at certain stages of the operation, is to reduce pressure, say from 6000 pounds per square inch in chamber II, to 5000 pounds in chamber |4,-or similarly at other pressure ranges, which efiect is of advantage in. enabling the valves ID to cut off sharply at all-(including low) engine speeds, and keeping the valve'clear when running slowly, as will be explained more fully in connection with the operating description hereafter.

Each valve I0 is seated in its bore far enough from the orifice B so that the capacity of chamber I4 is greater than the maximum single charge, thus preventing Mire-drawing. The preferred valve construction comprises a sleeve 20, closely fitting in its bore, and preferably seating by a shoulder 2| in such bore. The sleeve 20 is longitudinally centrally apertured at 22 and 23,

and also transversely apertured at 24 near the inner end, to connect with an outlet duct 4A in the distributor head I2. Inward of the transverse aperture 24, the central aperture is. enlarged as at 23, and finished with a tapered seat 25 at th front end. liesides being a close fit in the horizontal bore, the sleeve 20 is held in by a hollow gland screw 26 threaded into the back part of the bore and bearing at its inner end against a packing ring 21 preferably of 1ead,

solder or the like. a

A valve stem 30 with a flaring head 3| extends through the sleeve 20 and the gland screw 26 and extends out rearwardly into contact with the up- 35 of a valv leverl As best shown in Fig. 4, the valve stem 30 makes a close sliding fit in the portion 22 01 the aperture, but is cleared by the enlargement 23 so that when the valve is unseated, a passage is open from the chamber H to the dust 44. The valve stem 30 is constantly urged outward by a compression spring 35, bearing at its opposite ends on the bottom of the chamber l4 and on the valve head 3|. Inward motion is imparted to the valve 30 by the lever arm 35.

. The valve lever comprises angular arms 25 and 31 pivoted ona pivot 40. The upper arm 35, already mentioned, is stifl. The dependent arm,

31, much longer than 35 in the form shown, is inwardly inclined and adapted to be contacted at its lower end by a camnose 42 on a. rotor 43,

which rotor is splined to the upper timer shaft 9A.- A modified cam nos 42Ais shown on the tion of the casing 8 respectively. An oil diverholding-down screws-of a plate 58. The plate sion collar and a drain 41 prevent any oil which may leak through the valve from running down the shaft 9A, and drain it out. j

On account of the very small charges of fuel needed, and also on account of the very accurate measurement and termination of' supply which is necessary to efliclent operation, the valves I! must open and shut with a'snap under all conditions. This snap action is facilitated by making the lower valve lever arms 51 or 31A slightly resilient so that they do not open until the lower end of the arm is on the high part of the cam nose 42 or 42A. Thus, the travel occasioned by the diagonal sides of 42 first'causes tensing ofcomprises a pin with an eccentric intermediate portion 40 on which the-valve lever,is pivoted.

'The end 52 of'the pin bears in-a split ear 54' below the head l2, clamped therein bye. filister screw 54, and end 5| bears in a solid'ear. The

ends 5|, 52 ar mutually concentric, but are ec-' centric with the pin 40. A worm wheel. 551s fast to the end 5|, and when rotated :by a worm 54, I

adjusts the p0slti0n of 40, as apparent from the left side of Fig. 2. The head 51 of a screw which takes into the distributor head |2 prevents the assembly 555|50 52 from moving endwise'. The worm 55 has a slotted head, which can be clamped against movement by tightening the 58 has a central opening through which a screw driver. can be inserted to turn the worm 55 when the several clamp screws are loosened. The worm is held against down' travel by its own head and against up travel by the plate 58.

The rotor 43, which is splined to the upper timer shaft 9A is movable up and down on its splines by a rocking fork", to govern the amount of fuel supplied, according to load conditions. The fork 60 may be moved either by an automatic governor, or by the operator, as well understood in the art. The cam nose 42, as shown in Fig. 2. or 42A, as shown in Fig. 9, is wider at bottom than top, and thus the higher the rotor 42 is on the shaft the longer the cam holds each valve open.

To advance andretard the timing of fuelinjection, or to reverse the engine, the arrangement shown at the bottom of Fig. 2 is effective, al-

though others may be employed. The arrangement shown comprises a sleeve 65 spllned above of the sleeve 65 takes into'a spiral groove 55 in the lower end of shaft 8A.

Thus it is apparent that since the sleeve 55 constantly rotates with the main timer shaft 9, the vertical position of the sleeve changes the angular position of the cam nose with respect to shaft 8, thus causing an advance or retardation of the injection timing. The groove" is so cut that when the. feather 61 is at the mid-point of the groove, injection occurs in each cylinder at upper dead center; raising the sleeve gives lead to the inJection; lowering the sleeve lags the injection, and starting the engine with lag or giving it sumcient lag while running slowly will cause it to reverse, as is well understood in the art.

line pressure after the opening starts.

correspondingly, when closure begins the valve starts shut under the action of the return springs,

but as soon as the area between the seat andthe The distributor tubes 4 are made with very able manner, as by cap screws 82, and appropriately gasketed as at 83. The tip 8| is usually provided with a number of spray openings.

The fuel passages fromvalves to and through nozzles are of such size with respect to the physical properties of the fuel used, that the result attained by the invention is that the surface friction of the fuel on the walls of the duct, and the surface tension at the discharge orifice, offer suillcient resistance vto prevent any flow except when there is pressure. For example, with a head becomes smaller than the inlet duct, the pressure in i4 builds up and snaps the valve shut.

As previously noted, the passage from the distrlbutor to the nozzle is ofxcapillary size or capacity. For this reason liquid fuel movement takes place through the passages beyond the-distributor as soon as opening of the valve admits Pressure to such passages, but the flow ceases instantly when pressure is cut off, because, by virtue of the substantially capillary sizes, the viscosity of the liquid, surface adhesion of the liquid to the walls of the passage, and'surface tension across the final discharge orifices, are effective to stop any further flow, there not being enoughbody of liquid in the passage to overcome resistance and to dribble at the nozzle, and the rigidit of the walls of tubes 4 -prevents squeezing liqui out after valve .closu're.v

Other modes of applying the principle of my invention may be employed instead'of the one 7 explained, change being made as regards the means and steps herein disclosed, provided-those statedby any of the following claims or the equivalent. of such stated'means be employed.

In the claims the word high" is' used to mean pressures on the order of those used for inJeclarger size tube, the liquid in the tube would continue to dribble out of the nomle after the pressure was cut oil, thus completely destroying any accuracy of feed. Another way of stating the same thing is that I apply the term capillary to a tube of such characteristics that when applied pressure (as from the pump 2) is cut off, the' pressure on the liquid in the tube due to forces other than applied pressure (e. g., gravity, expanding tendency in the liquid, any trace of surge effect, and other influences tending to make the tube empty itself) is less than the surface tension at the discharge orifice. It has been customary in Diesel engine practice to apply pressure very close to the point of injection to avoid this difficulty, but in myinvention the use of a substantially-capillary passage makes such a provision unnecessary, because no oil whatever passes out of the nozzle opening after the'valve head 3| seaga:a at 25. The word capillary as used in the s thereto is to be interpreted in this sense.

The action of the mechanism is as -follows: Pressure being applied by the pump 2, fuel oil under high pressure is supplied to the central and the quickness of this action, especially when cranking over to start or when running at low speeds, is assisted by the following effect: when the valve starts to lift, the first very slight relief of pressure in the side chamber I l permits quick completion of the opening under the spring tension in the valve lever arms 31, so that a snap opening results. By reason of the greatly re- :duced passage, the pressure in the central chamber does not immediately replace the drop ciilcation and the claims appended As each valve,

- verging ends of said arms and acting upon said tion of fuel into Diese1 engine's, without, how ever, limiting the claims to this field unless they are so limited by other expressions. h I therefore particularlypoint out and distinctly claim as my invention; a U 1. A-fuel distributor for anrintemal combustion engine comprising in combination a central pressure chamber, a plurality of valve chambers radially disposed about said central chamber, axially movable valves in said radial chambers. levers for movement of said valves pivoted adiacent the outer ends thereof, said levers including arms depending and converging below said radial chambers, and a cam within the converging ends of said arms and 'acting upon said ends.

2. A fuel distributor for an internal eombuse tion engine comprising in combinations central pressure chamber, a plurality of valve chambers radially disposed about said central chamben axially movable valves in said radial chambers,-

resilient levers for movement of said valves pivoted adjacent the outer ends thereof, said levers including arms depending and converging below said radial chambers, and a cam within the con-- ends. '-8. A fuel distributor for an internal combustion engine comprising in combination a body, a

pressure chamber therein, a plurality of valve chambers disposed about said pressure chamber, a valvein each such. chamber, a valve stem protruding from each such chamber, a lever of the first order for each valve pivoted to said body, said levers having arms of unequal length,- the short arms bearing respectively against said stems for'axial thrust, the long arm extending beyond said body, and a cam disposed centrally of said long arms and acting upon said long 4. A fuel distributor for an tion engine comprising in combination a body. a pressure chamber therein, a-plurality of valve '3 caused in by thebeginning of the opening', so that the valve opening is opposed by less than full internal oombus-' long arms extending beyond said body; a cam disposed centrally or said long arms and acting upon said long arms, a liquid-tight casing enclosing said body, said levers and said cam, and v a drain from said casing.

L JERTQN J. SMITH.

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