US2516692A - Fuel injector - Google Patents

Description

July 25,

1950 L. o. FRENCH FUEL INJECTOR Filed Sept. 23, 1946 Fig. 6

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- Patented July 25, 1950 UNITED STATES PATENT OFFICE FUEL mn-zc'ron Louis 0. French, Milwaukee, Wis. Application Septenibcr 23, 1946', Serial No. 698,834

The invention relates to automatic fuel injectors of the general type which utilize the compression pressure of the, engine to operate a piston which moves relative to a high pressure plunger to produce the injection of fuel into the cylinder of the engine and particularly to an injector in which the stroke of the operating piston and hence the eflectlve stroke of the high pressure fuel plunger is controlled by checking the movement of said operating piston by a checking fluid whose release is controlled by the angular setting of said piston relative to a relief port. One object of this invention is to provide a new and improved means for effecting the angular adjustment of said operating piston over those of my copending applications for Automatic Fuel Injectors, Serial No. 592,675, filed May 8, 1945, and Serial No. 676,952, filed June 15, 1946.

A further object of the invention is to provide an improved and simplified form of automatic fuel injector using a differential needlevalve as the injector, valve and in which the valve seat and guide are formed in the operating piston to which a sleeve forming a checking piston is secured.

A further object of the invention is to provide an automatic fuel injector in which the operating piston carries a, fuel pump chamber and the acceleration of said piston at the beginning of injection is accomplished by a conduit member detachably secured to said piston and having a conical surface engageable with a, valve seat on a fixed stop member.

The invention further consists in the several features hereinafter set forth and more particularly defined by claims at the conclusion hereof.

In the drawings:

Fig. l is a vertical sectional view of a fuel in- .l'ector e bodying the invention, parts being broken away;

Fig. 1A is a vertical sectional view of an in- 5 Claims. (01. 103-54) cludes a housing having a bottom end portion I, a cylinder 8, and a cap 8, the parts I and 8 adapted to bemounted in the head In of an internal combustion engine and secured thereto by a threaded connection |l therewith. The part I is a stop member andhas an annular valve seat l2. The cylinder 8 has a bore l3 extending therethrough with a shoulder II and a threaded portion II at its outer end and is provided with a relief and checking fluid supply passage It, a. passage I! for lubricant orin some instances fuel. The cap 9 has a flanged end seating on the shoulder ll against which it is clamped by a sleeve nut ll, a guide bore l9, and a valve seat 2|! at the inner end of said bore.

An operating piston 2| working in the bore I3 is moved in one direction by the compression pressure of the gases in the combustion chamber C of the engine and in the opposite direction by a spring 22. This piston has a conical end 23 normally seating on the seat |2 to reduce the piston area initially exposed to the compression pressure and thus reduce the required lo ding of the spring 22 and also permit rapid piston acceleration after said seat is uncovered. It is provided with sealing rings 24, wrench orvvise engaging flats 25, an annular groove 26 communicating with passage l1 and is differentially bored to provide an inwardly extending flange 21, a threaded bore 28, and plain bores 29 and 30 forming a. shoulder 8|.

A conduit member 32 fits the bore 30 with its flanged end abutting against the shoulder 3| and is recessed to receive an apertured valve seat 33 which abuts the end of a pump barrel 34, these parts being clamped together in assembled relation by a hollow. wrench-socket-headed screw 35 engaging the bore 28. The conduit member has spray orifices 30 controlled by a normally spring closed valve .31 which is opened by fuel pressure on the outward or upward movement of piston 2| Any other form of nozzle or discharge valve may be used with piston 2|.

The barrel 34 fits the bore 29 and is recessed between its end to provide an annular cooling space 38 which is connected to its interior by inlet ports 39, and in Fig. l is connected at its ,upper end by vertical grooves 40 and radially disposed grooves 4| to the hydraulic chamber 42. Where the fluid used in said checking chamber is a lubricant, then the grooves l0 and 4| are' omitted. a compressible gasket inserted in the space 43 and a passage ll, shown in dotted lines in Fig. 1, connects the space 38 with an annular groove 28' in piston 2| which registers with the ac aees 3 passage |1, so that fuel under suitable supply pressure is supplied to said space 38. Thus in one instance the fuel itself may be the checking fluid, and in the other a lubricant is used as a checking fluid.

A high pressure pump plunger 45, working in the barrel 34 controls the ports 39, and after their closure on the outward movement of piston 2| or its movement away from the combustion chamber C, fuel is compressed in the barrel between said plunger and valve 31 until the spring pressure closing said valve is overcome, and then this fuel is discharged into the combustion chamber C through the orifices 36, the amount of fuel depending upon the relative movement of said plunger and barrel 34 or piston 2|. To vary this moved outwardly by the gases of com ression the particular part of theavailable stroke period at which this occurs being determined by the angular setting of said edges 41 and 48 relative to said port so as to produce either a complete lapping of this port relative to the control edge 41 with no movement of piston 2| or a lapping of said port after a predetermined movement of said piston.

For atfiusting the angular position of control edges 41 and 48 relative to the port IS. a rotatable valve like member 49 mounted in the bore l9 and seating on the seat 20 has de ending key projections 58 slidably engaging in key slots 5| in the flange 21 of piston 2|. The exposed end of the stem of member 48 has an operating handle 52 slidablv keyed thereto and normally secured by a nut 53 against a shoulder on said stem which nut may be loosened to allow inward movement of the valve for priming purposes. The spring 22 engages the head of plunger 45 which in turn' abuts the head of member 48, so that the same is normally sealed against the cap 9. By rotation of the member 49 either through the handle 52 or any other suitable turning means, such for example, as a rack and pinion, the piston 2| is moved to the desired position relative to the port It.

For facilitating setting Of the angular position of piston 2| relative to port IS the operating means for the member 48 is provided with an index pointer 54 cooperating with index markings N, H, and F on the cylinder 8 corresponding to no load. half load', and full load positions of control edge 41 relative to said port, it being noted that the pointer 54 is diametrically opposite the control edge 48 in the full load position of the handle and that as saidpointer is angularly shifted toward the right as viewed in Fig. 5 said control edge 41 will finally lap the port l8.

With the above construction the loading of the spring 22 is such that when the compressoin pressure of the engine has reached a predetermined amount and overcomes this spring loading, the piston 2| is moved outwardly of the combustion chamber 0 effecting closing of the fuel ports 39,

the compression of the fuel in the high pressure 4 9, the part 86 having a relief and checking fluid supply port 58 and a fuel supply passage 88, the cap 51 being secured to the top of cylinder 58 by a nut similar to the nut l8.

A piston formed of parts 8| and 82 works in the bore 63 of cylinder 58 is moved outwardly by the compression pressure oi. the gases in the combustion chamber C Of the engine and inwardly into abutting engagement with the stop 55 by a spring 84, said piston having a conical end cooperating with the part 55 as in the first described form. The piston part 6| is provided with sealing rings 85, wrench engaging flats 88, an annular groove 81 connecting a port 88 with the passage 58, a threaded outer end 88 of reduced diameter, a valve guide bore 10, a seat 1|, and a spray orifice 12. The part 82 is'a tubular member having a threaded inner end to fit the end 69 and an inwardly extending flange 13 which is provided with key slots similar to the slots 5| of the first form.

A diflerential pressure operated needle valve 14 has its stem slidably guided in the bore 10 and seats on seat 1| and may have a pintle projection 15 cooperating with the orifice 12 to form an annular fuel spray passage.

The stem of valve 14 is provided with a bore 18 connected by passages 11 and 18 with a chamber 19 above the seat 12, and a high pressure pump plunger 80 works in said bore to control a fuel inlet port 8| therein, and is normaily held against longitudinal movement by the spring 84 which is interposed between the head of the plunger and the outer end of the stem of valve 13.

The part 62 is provided with a V-notch 82 to form control edges similar to the edges 41 and 48 which cooperates with the port 58 in the same way that the port It cooperates with said edges to control the amount of checking fluid released from the chamber 83.

For angularly adjusting the two-part piston to change the position of said notch 82 relative to said relief port 58, the means shown in the first constructoin and similarly numeralled is used.

The construction shown in Fig. 6 embodies specific improvements over that-of my application Serial No. 676,952 previously referred to and which earlier filed application contains claims to the common subject matter. In this modified construction when the compression pressure in the engine is sufllcient to overcome the loading of the spring 84, the twopart piston BI, 82 is moved outwardly, causing the plunger 89 to lap the ports BI and compress the fuel in bore 16 and chamber 19 until the pressure acting on the differential area of the valve 14 is sufficient to overcome the spring 64, and then said valve 14 is moved slightly relative to the operating piston and the seat H and fuel discharged through the orifice 12 until the notch 82 moves into lapped relation with the port 58, and further movement of the operating piston is stopped by the checking fluid in the chamber 83.

The construction shown in Fig. 1A is similar to that of Fig. l and operates similarly. The

modification resides in forming the conduit member 84 corresponding to the conduit member 32 of Fig. 1 as a clamping nut for holding the valve seat member 33 and the barrel 34 in place, when the barrel is formed as a separate structure, and also for providing a sealing seat 85 cooperating with the seat |2 of the casing part 1, said nozzle having wrench engaging flats 86. The parts 33 and 34 associated with the nozzle 84 are clamped together and the barrel 34 clamped against a shoulder I! formed in the piston II, the conduit member it having a threaded connection II with said piston. With this construction the screw 35 is dispensed with and the conduit member may be removed from the piston 2| without removing said piston from its housing. Also the area of the throttling restriction provided by the surfaces 85 and I2 is reduced over that of Pig. 1 so that the spring 22 does not have to be as heavily loaded.

Itisalsotobenotedthatthecaplmayin some instances be formed as an integral part of the cylinder 8 in which event the nut I8 is eliminated.

Reference is here made to my copending application Serial No. 748,140, filed May 14, 1947,

for Fuel Injector, for any cooling features common to these cases.

I desire it to be understood that this invention isnotto be limited to any particular form or arrangement of parts except in so far as such limitations are contained in the claims.

What I claim as my invention is: 1. In an automatic fuel injector in which a high pressure fuel pump of variable stroke is.

associated with an operating piston movable in response to fluid pressure and provided with control edges, the combination of a cylinder in which said operating piston works with which'it forms a checking fluid chamber having a relief port cooperating with the control edges on said piston, and means for angularly adjustingsaid control edges relative to said port comprising a rotatable member moimted in the outer end of said cylinder in fluid sealed relation with said chamber and operatively connected tosaid operating piston.

2. In an automatic fuel injectorin which a high pressure fuel pump of variable stroke is associated with an operating piston movable in response to fluid pressure and provided with control edges, the combination of a cylinder in which said operating piston work; and with which it forms a checking fluid chamber having a relief port cooperating with the control edges on said piston, and means for angularly adjusting said control edges relative to said port comprising a rotatable member mounted in the outer end of said cylinder'in fluid sealed relation with said chamber and having a slidably keyed connection with said operating piston.

3. In an automatic fuel injector, the combination with a cylinder having a relief port, of an operating piston movable in said cylinder in response to fluid pressure and provided with a fuel pump chamber having a fuel pressure controlled outlet, said piston and-cylinder forming a checking fluid chamber, said piston having control edges cooperating with said relief port to vary the amount of checking fluid released from said checking fluid chamber to vary the stroke of said piston, a plunger for said pump chamber fixed against longitudinal movement, on angular-1y shiftable member mounted in fluid sealcdrelationintheouterendoflaidchecking fluid chamber and having a slidably keyed connection with said operating piston to vary the position of said control edges relative to said port.

. said plunger abutting said member, and a, spring interposed between said piston and plunger for returning said piston, holding said plunger against longitudinal movement and retaining said member in sealed engagement with said cylinder.

4. In an automatic fuel injector, the combination with a cylinder having a checking fluid erating with said relief port to vary the amount of checking fluid released from said chamber, a differential pressure operated needle valve seating on said seat and having a stem slidably mounted in said guide bore and provided with a pump bore communicating with said seat, a

high pressure fuel pump plunger working in said' pump bore, a fuel port in said stem controlled by said plunger, means for supplying fuel to said port, a spring interposed between said valve and plunger for returning said piston, closing said valve and holding said plunger against longitudinal movement, and means for angularly adjusting said control edges relative to said relief port comprising a rotatable member mounted in the outer end of said cylinder in fluid sealed relation with said chamber and operatively connected to said operating piston.

5. In an automatic fuel injector, the combination with a cylinder, of an operating piston movable in said cylinder in response to fluid pressure and provided with control edges and a fuel pump chamber, a valve controlled outlet for said chamber including a valve seat member, a conduit member having threaded connection with said piston, said conduit member having a conical surface, a stop member forming a valve seat cooperating with said surface, a pump P un working in said pump chamber, said cylinder and piston forming a checking fluid chamber having a relief port cooperating with the control edges on said piston, and means for angularly adjusting said control edges relative to said port comprising a rotatable member mounted in the outer end of said cylinder in fluid sealed relation with said chamber and operatively connected to said operating piston. Y Louis 0. FRENCH.

summons crrEn The following references are of record in the file of this patent:

2,371,787 Ward Mar. 20, 1915

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