US2598528A

US2598528A - Fuel injection apparatus

Info

Publication number: US2598528A
Application number: US66279A
Authority: US
Inventors: Louis O French
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-12-20
Filing date: 1948-12-20
Publication date: 1952-05-27
Anticipated expiration: 1969-05-27

Description

May 27, 1952 L. o. FRENCH FUEL INJECTION APPARATUS Filed Dec.

En imDrive INVENTOR.

5L4: O "bu-HALL Patented May 27, 1952 UNITED STATES ar-s ur Appiicatibnbeciember 20, 19248,

50mins. 1 The invention relates to fuel injectors for t l omb stion en ines and more particue larly to those of the cembin'ed fuel pump and sprayer type generally known as unit ijnJeetor's. In n t inj ctors of kn w onstriibti n th f uel pump plunger is opera e by a cam Operate lever fro'in the engin Cam drives have distinct limitations because they generally necessitate s g as a min mum uc d gree 1 cram; an le rotation faste prevent all the fuel being injected into the engine during the peirw 9f ignit'io'n leg with the result that the fuel'air ratio is netas igoqfd as it should be since the last portion of the fuel cl'ia'rge may net 'ihix' with its required air component resulting in incompl te combustion. Usually injection with cam operated in"- jectors occurs within twenty to fifteen degrees of engine crank angle whereas better fuel mixing and economy 'cculd be obtained if the injection period were cut down up half or preferably less than half or this fijgu're. Furthermbre, with 'eam operated :ue1 plunger's the rate er speed ()f injectioh -varies with engine speed so that injection efiicienc'y decreases with a decrease in engine speed. fI he ab'e'v'e 'objectien's can be ever come where the fuel plunger 'is operated by a hydraulie actuator, and pink: bbje'ct of this in"- vention is to provide a hydraulieally operated plunger operating piston operated by an external source of hydraulic pressure fluid at any desired pressure suitable for rapid operation of the fuel pump plunger to deliver its fuel charge at any desired injection pressure and at a rateindependent of engine speed, the pperatioh of said operating piston being controlled by a timing valve operable in cyclic 'synchronisr'n with the engine. I

A further object of the invention is to provide a fuel pump having a double acting hydraulie motbr actuator whose operating piston is angularly adjustable from one end of the inoto'i't'o vary the metering effect of the pump, the arrangement avoiding the nece sity for a stern in'g 'b'o' x or ether speeial seal between the high and lower pressure -'cylinders or barrels.

A further Object of the invention is to provide a fuel pump whose pump plunger is operated by a hydraulic inotor actuator whose operation is cent-relied by an electromagnetical'ly operated timing valve whose control switch may be readily applied to any engine and may be used to control a plurality of pumps for a single engine cylinder as in the ease of opposed piston engines. The invent-ion further e nsiste in the several features hereinafter set term and more Particularl q fin a ms a we cisfie liisi t n the u wings- V a annu ar greove 18 the b with Said iil'rts l3, vert-iqa-l green I!!- barrel and portlfl.

The discharge Valve assfhly may eeinpri-seany suitable cheer; have to 1 from thepiimp chamber 521-. As hem-1, check valve 22 *sli'dably rammed in a sleeve easing 2'3 is normally {urged into eentac't with the apertureeseat (if a seat memb'er -2'4 by a spar-lees 40 The discharge member- M may he or any sure able cen traenorl prev ided with an? editable i162 zl 6i valve 'c' cihti'olled ne'zzl'e and as ShdWh' has a discharge passage 2% provided with spray 'Qifi flees -21; V

in both rams the ievp on the p p plunger 1% is moved beware-1y 611 its e e g strbke and. inwardly on its fuelihi dtinstro e by a hydraulic rnotor' -aeti iato r ii i 1' d ap tbii 29 are n ct u e in S t erin re ati n 3th cylinder 28 being formed inte to the upper end of the hou Wilme 2 i be ie-c lii =l p nnec wirhe .11 m 1 suitable sealing ring 30 and has a be 3 axial with the plunger l2 and of greater diameter. A cap or top 32 is secured by screws 33 to the upper end of the cylinder with a fluid-tight connection provided by a sealing ring 94.

A spring 35 interposed between the. housing and the piston 29 acts to overbalance the weights of the piston 29 and plunger l2 and tends to move them outwardly.

In Fig. 1 the self-centering direct connection of the plunger [2 and the piston 29 is provided by a nut 36 in threaded engagement with said piston and forming therewith a plunger head retaining pocket having side clearance for said head and plunger shank.

In Fig. since the plunger I2 is to be angularly adjusted through the angular adjustment of the piston 29 the self-centering direct connection between the plunger |2 and the piston 29 comprises the nut and an Oldham or universal coupling comprising a circular coupling plate 31 having diametrically extending

ribs

38 and 39 on opposite sides thereof and disposed at right angles to each other, the rib 98 slidably mounted in a groove 40 formed in'the piston 29 and the rib 39 slidably mounted in a roove formed in the head of the plunger, the plunger having side clearance in its mounting pocket.

Referring to Fig. 1, the cylinder 28 is provided withports 4|, 4'2, 43 and 44 communicating. with the bore 3|, a passage 45 connecting

ports

43 and 44, a valve bore 46 connected with the port 4| and passages and 48 and with spaced pressure fluid supply ports 49 and connected to a sup- 7 ply port 5|. The lower portion of the piston 29 is provided with a notch forming control edges 52 and 53 which cooperate with the relief port 43 whereby angular adjustment of said piston relative to said relief port will cause said control edges to cut ofi communication between the checking fluid chamber 54 in the lower end of the cylinder 28 and said relief port sooner or later in the inward movement of said piston to provide a variable hydraulic stop so that both the piston 29 and the plunger It will have their stroke varied, thus varying the amount of fuel delivered to the engine by the injector.

Referring to Fig. 5, the cylinder 28 is provided with

ports

55 and 56 communicating with the bore 3| above and below the piston and with a valve bore 51 with whichdrain ports 58 and 59 and a pressure fluid supply port 69. also 'communicate, said piston 29 and plunger l2 being given a constant stroke by the hydraulic motor actuator. For metering the fuel theplunger |2 has a recessed portion 6| providing a control edge "62 and a slot 63 extending from said recess to the front end of said plunger, said control edge cooperating with one of the ports I3 whereby angular displacement of said control edge relative to said port 13 will by-pass fuel from the pump chamber 2| sooner or later and thus vary the amount of fuel delivered by the injector to the engine. 7

Thus in both instances metering is effected through an angular adjustment of the motor piston 29. In Fig. 1 said piston 29 acts to ad- 'u st the stroke of plunger I2 to vary the fuel 7 charge while in Fig. 5 the angular adjustment of the constant stroke piston 29 and its associated plunger l2 acts to vary the "amount of fuel by-passed from the high pressure pump chamber to vary the fuel charge.

'In each instance for angularly adjusting the piston 29, a rod or key 64 mounted in the outer end]thereof-extends'across a cavity 65 therein and slidably works in a key slot 55 formed in the head 61 of a metering control member 68 extending into said cavity. Member 58 is rotatably mounted in the cap 32 in sealed relation therewith by forming said member as a valve having its head 91 seating on a'valve seat 99 in said cap and its stem 10 working in a bore H in said cap, said member being normally held to its seat by a spring 12 interposed between said cap and a washer 13 secured to said stem which also carries an operating handle '54 for manual or governor control. Stem 59 may be provided with grooves '.'5 so that the outer end of the cylinder may be purged of air by pushing inwardly on the valve to unseat it and thus permit ready priming of this part of the hydraulic system.

The piston 29 has an annular groove 15 which in Fig. 1 is connected by one or more ports ll with the upper end of the chamber 54 and registering in the outer position of said piston with the exhaust port 44 so that in this position of said piston any air that might be entrained in the hydraulic actuating liquid will be free to escape and thus the lower end of the cylinder 29 will be self-purging.

' For operating the hydraulic motor actuator means are provided for supplying hydraulic fluid thereto at any desired pressure. Referring to Fig. i, this means includes a liquid supply tank T for either a lubricant or fuel connected by piping including a strainer S to a motor or engine driven pump P preferably of the constant displacement type though other types may be used, said pump delivering to a standpipe SP connected by branch connections B to supply ports for the injectors I and connected by return piping R to the tank T, a pressure relief valve PR being mounted in a pipe BB connecting with the pipes SP and R. ihe relief valve PR may be set to deliver the operating liquid to the injector operating motors at pressures of flve' hundred to a thousand pounds per square inch or any desired pressure and the ratio of the areas of the fuel plunger l2 and the piston 29 may be 1 to 10 or 15, for example, de-

pending upon the fuel injection pressure desired.

The rate of injection will depend upon the supply pressures and the areas of the ports in the motor cylinder. For best results the rate of injection should be such as to inject the fuel charge into the engine within the period known as ignition lag and the pressure should be high, for example, 10,000 to 15,000 p. s. i.

The flow of pressure fluid to and from the hydraulic motor actuator is in each instance controlled by a piston valve. In Fig; 1 the piston valve E8 is slidably mounted in the bore 49 and is provided with annular grooves forming lands is, 30 and 8| and is normally urged in one direction by a spring 82 interposed between its exposed head 83 and a stop plate 94, and whenengaged with said stop as shown in Fig. 1, the port 49 is lapped by the land 19, the port 4| is connected through the upper groove in the valve with the passage 41 shown diagrammatically as ex.

tending around the bore 3| and connecting with the exhaust 44, the port 59 is connected through the lower groove in the valve with the passage 49 including port 42 which oonducts pressure fluid from the supply port 5| into the chamber 54 and acting on the lower face of the piston 29 ,quickly raises it and the plunger It to the position shown in which the fluid is then free to pass out through the

port

43, 45 and 44 to the return pipe.

When the valve 78 is shifted so that the land 8| laps the passage 48 and port 50 and the land 86 laps the passage 41 an'dthe land 19- moves out of lapping relation with the port 49 "so that this port and port '41 are connected together by the upper groove of the valve, then the pressure fluid flows through port 41 to the upper end of the cylinder 28 moving the piston 29 and the plunger I9 downwardly against the pressure of the spring and puts pressure on the fuel in thepump chamber 21 until the loading of spring '25 is over-- come and valve 22 then opens allowing-fuel to pass through member 14 and its orifices 21 into the combustien chamber C of the engine. When, onthis downward movement of the piston '29, the

control edge '52 laps the relief port 43, hydraulic fluid trapped in the chamber 5% and forms a hydraulic stop preventing further inward movement of said piston and. the plunger I2 and in jeetion stops. When the valve 1-8 is again shifted back, the hydraulic fluid, as previously described,

together with the spring 35 'moves the piston 2:?

in one direction by a spring as in the first described construction. When said valve is in the position shown, fluid from the upper end of the bore 3! is free to pass through ports and 53 to the return while pressure fluid supplied through port iii] passes by way of port 58 to the lower end of the bore '31 acting on the piston and its associated plunger to raise the same to the position shown. When on the downward movement of this valve Bethe land 86 moves into lapping relation with the port 58, the land 88 out of lapping relation with the port 59 and the land '87 to a position below the port 60, then the pressure .fluid will flow from the port to the port 55 moving the piston 29 and plunger 12 downwardly while fluid is exhausted from below said piston through the port 56 and port 59 to the return.

In Fig. 1 I have shown a manually adjustable throttle valve 89 connected with the exhaust port 44 to vary the rate of flow of liquid from the lower end of the cylinder so that the rate of injection may be varied, if desired. This same valve 89 may be connected with the drain or return port 59 in Fig. 5 for a similar purpose.

When the engine is provided with an overhead cam shaft or valve shaft 90, the valve 13 may be operated in cyclic synchronism with the engine either directly by a suitable cam 9| on said shaft or as shown in Fig. 3 by a pivoted lever 92 operated by the cam 91 on said shaft and acting on the head 83. The valve may be similarly actuated, but since this valve is in a normally raised position when the injector is not operating, the cam 91 will have a depressed portion substituted for its nose 93 shown in Fig. 3. Where it is not convenient to use such a cam shaft drive or the engine does not have or need an auxiliary shaft adjacent the injectors as, for example, in many two cycle engine designs, then the means for operating the

valve

78 or 85 is preferably an electromagnet such as a plunger type solenoid electromagnet E of the iron clad type shown in Fig. 1 including the energizing coil 94, the magnetic stop 95 provided with an anti-freeze stop projection 96 and the plunger 91, which may form an extening as a relief valve.

' 6 sionof the verve ia ana a :co'ntrm circuit for said m netinciuding an engine operated switch or timer'SB.

The controlcircuit includes a conductor 99- conhecting one side of the coil 94 to one terminal of a battery we orbther suitable source or di rec-t current and a eondueter ifl'l connect other terminal of said witna be p I i532 of the switch 53.. The other side of the-coil 94 is gram-idea at we. The switch includes an engihe drive'n retaryswitch contact 1-94 cbn l'iebted to ground which cooperates with thesuitabiy insul contact 102 to close the "circuit through the b nnectiehs ab'ov'e desdr i'bed to energize the coil 94 at such a time the engine s-eyele as will insure mo'v'ment of the valve 7 8 With its plunger 91 against the action of the spring '82 to its upper or fuel injection position so the. jection may start, for example, within ten-tonne degree or bra n-K angle before top dead center, the contact H32 being angularly adjustable to ac commodate for the electrical in theel'e romagnet and in order that 'this electrical lag l not interfere with the operation under varying engine speeds, the switch as is preferably of the type having a built-in automatic or speed controlled angular advance for contact I04, as for example, a governor controlled tuning-switch of the type shown in my prior- U. s. Patent No. 1,705,655, dated March 19, 1929. Where more than one injector is used-per cylinder, their valve operating electr'omagnets are connected in parallel' with the control switch. The valve 85 may also be solenoid con-trolled, and with the form shown in Fig. 5 using the solenoid shown in Fig. l the controlswitch 98 would be closed during-the time the valve 55 is in the position shown and the injector is not operating.

To decrease the capacity of the pump .P the hydraulic 'operatingsystem may be provided with an accumulator to build up a supply of pressure fluid during the non-working period :of the injeet'or, and in Fig. 4A I have shown an accumulator suitable for this purpose and also function- This device includes a casing [15 having a bore I06 provided at .itslower end with an inlet Hi1 and outlet I08 which may form part of the standpipe SP and provided with a relief port 409 and a port l I0 connected with A the port H39. An accumulator and v'alvepiston H 'I having a slotted lowerend works in the bore H16 and is urged by the hydraulic fluid against a pressure determining spring I I2 whose tension maybe adjusted bythe adjusting screw 1 l3. having threaded engagement with the casing "cap- H4 and bearing on a spring seat member '5 slidably mounted in sealed relation with a bore H6 in said cap. With this arrangement during non-working periods of the injector or injectors the pressure acting on the piston Ill moves it upwardly against the loading of the spring H2 until the lower slotted end of the piston passes the relief port I09 at which time fluid may then flow through said relief port to the return pipe R with which it is connected. During the time the

valve

18 or 85 is moved to cause the injection stroke of the piston 29 and plunger I2, the pressure built up by the accumulator piston is utilized to aid in producing a quick movement of said piston and plunger.

While the

valves

18 and 85 are shown as built into the cylinder, they may if desired be separate units connected by suitable piping to the motor cylinder as will be readily understood.

While lubricant may be used for the operating fluid,;where fuel oil is used in the engine, it may be used as the pressure operating fluid inwhich event the fuel supply passage I6 in the injector may be connected in, circuit with the exhaust port 44;0r 59 or the outlet from valve 89 when associated, with either-of said ports and from a partof the returnpipingf and the piping con nections thus simplified. V

The above construction permits introduction of fuel at any desired pressure and at any desiredrate, which rate is independent of engine speed so that injectionefficiency will not decrease with engine speed and the period of injection may bemade so short that with good combustion chamber design the air-fuel ratio will more; nearlyapproach the limit of saturation, that is to say, a theoretical fuel air; mixture containing no excess air, with a resulting increase in engine efficiency. i

I desire it to be understood that this invention is not to be limited to any particular form or arrangement of parts except in so' far as such limitations are included in the claims.

What I claim asmy invention is:

1. In a fuelinjection apparatus having a high pressure plunger fuel pump, the combination of a hydraulic operated'actuating piston connected tothe plunger of saidpump, an exterior source of hydraulic pressure liquid at a predetermined pressure lower than the delivery pressure of said pump for operating said actuating piston, valve means operable in cyclic synchronism with the engine for controlling the passage of said'hydraulic liquid to and from said actuating piston,

valve means for controlling the quantity of fuel delivered by said pump, and externally adjustable means for controlling said valve means including means for angularly adjusting said ac tuating piston.

2. In a,v fuel injection apparatus for internal combustion engines having a plunger fuel pump, the combination of a hydraulic motor mounted on said pump including a cylinder and an operating piston Working in said cylinder and direct connected to the plunger of said pump, the inner end of said cylinder and the piston cooperating to form a checking fluid chamber, said cylinder having ,a relief ,port communicating with said chamber, saidpiston having a control edge co-' operating with'said relief port to trap liquid in said chamber, means for angularly adjusting said, pistonto vary the position of said control edge relative to said relief port to vary the stroke of said piston and said plunger, means for supplying hydraulic operating liquid to said cylinder at a predetermined pressure, and valve means operable in cyclic synchronism with the engine for controlling the passage of said hydraulic liquid to and from said cylinder. 1

3. In a fu el injectionepparatus for internal combustion engines having a plunger fuel pump, the combination of a hydraulic motor'mounted on said pump including a cylinder and an operating piston working in said cylinder and direct connected to the plunger of said pump for reciprocatory and rotary movement therewith, said pump plunger having a control edge, said pump having a barrel provided with a relief port cooperating with said control edge to vary the fuel charge delivered by said pump, means for angularly adjusting bothsaid operating piston and said plunger to vary the position of said relief port relative to said control edge including a rotatable control member mounted in said cylinder and having an exteriorly disposed operat:

ing connection, means for supplying hydraulic operating liquid to said cylinder at a predeter:

mined pressure, and valve means operable in V cyclic synchronism with the engine for controlling the passage of said hydraulic liquid to and from saidcylinder I 4. In a fuel injection apparatus for internal combustion engines having a plunger fuel pump,

the combination of a hydraulic motor actuator for the plunger of said pump, an exterior source of hydraulic pressure liquid at a predetermined pressure for operating said actuator, a piston valve for controlling the passage of said hydraulic liquid to and from said actuator, an electromagnet for controlling said valve, and a control circuit for said electromagnet including an engine operated switch.

5 In a fuel injection'apparatus for internal combustion engines having a plunger fuel pump, the combination of a hydraulic motor actuator for the plunger of said pump, means for supplying hydraulic pressure fluid to said motor at any pressure needed to produce the desired injection pressure, and a variable throttling restriction means for controlling said motor so as to move said fuel pump plunger at any desired rate.

LOUIS O. FRENCH.

REFERENCES CITED The following references are of record in the file or" this patent:

UNITED STATES PATENTS Number Name Date 1,084,715 Steinmann Jan. 20, 1914 1,443,102 Suekert Jan. 23, 1923 1,705,665 French Mar. 19, 1929 1,816,157 Scott July 28, 1931 1,976,040 Scott Oct. 9, 1934 2,263,086 Hall Nov. 18, 1941 2,276,358 Vickers Mar. 17, 1942 2,343,962 Dodson Mar. 14, 1944