US2499706A

US2499706A - Injection pump

Info

Publication number: US2499706A
Application number: US19948A
Authority: US
Inventors: Patrick C Ward
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-04-09
Filing date: 1948-04-09
Publication date: 1950-03-07
Anticipated expiration: 1967-03-07

Description

March .7, 1950 p, C, WARD 2,499,706

INJECTION PUMP Filed April 9, 1948 IN VEN TOR. PAM/ce I )f1/4e@ BY www Arme/1w? Patented Mar. 7, 1950 UNITED STATES PATENT "()FFICE NJ ECTION 4PUNP Platxfck C. Ward, San FranciscmCa'lif.

'AppliGat'OWAp'ri'lf 194.8, Serial N0. 195.948

6 Claims. (Cl. A12S-'140) 1 'This invention relates to'f'al'fuelinjection'purnp Afor an internal combustion fengine, `zmore yparticularly, a 4Diesel "engine, and 4to :an electrical system fior controlling the pump and v:governing the speed of the engine.

In the ordinary Vfuel injection system :of a

Diesel engine, there lis vprovided a high Ypressure reciprocating pump, which Tis actuated by .acam

'keyed'to or actuated lby the `'crankshaft of the fengine. In one such system the stroke of the pump piston 'is 4varied to 'govern zthe yamount :of fuel injected into the engine; hence, the speed and power output o'fth'e engine. Such variations fof stroke :of vthe pump `piston Lis Caccomplished by various means; ."iorexample, a beveled cammay 'be used, 1and the cam yshifted perpendicularly to the laxis o'f the pump piston so fas `to present by altering the strokeof the'piston.

This and `other mechanical systems @of controlling the feed o'f y'fuel to a Diesel 'engine or the like are objectionable, in vthat r`-adjustable parts, such as the'above-mentioned beveled cam,

are subject lt'owear, develop play Iandrequirelfre'- 'quent adjustment and repair in usage.

It is .an object Iof this 'invention to provide van fimprcved means fof `controlling the supply of ifuel to 'fa Diesel lor-otheririternal combustion 'en- Lgine.

Itis a'further object of the invention ".to provide 'a vsystem for governing the 'supply vvof nfuel to a Diesel engine lor the like, which vavoids l'or minimizes the employment of mechanical -elements which develop 'wear and iplay nuringusage .an'dre'quire 'frequent repair.

fto'fthe load Von the `rengine.

It is 1a still further iobj'ect fof ythe invention to provide 'an electrically sgovcrne'd 'fuel ffeed "system :for a Diesel vengine :or the like, 'which measures vthe .fuel input by displacement, land ywhereby `the -fuel displacement is rapidly and accurately Vre'- Asponsive to the load Vorto a rheostat or the like. These and other objects of the invention 4will be apparent .from the 'following description and the ensuing claims.

The Ainvention will be better understood by ref'- =rence tothe accompanying drawings, Yin which fone .form which .the invention :may :assume fis vgine l(not shown) 2 Referring lnow to :the drawings: Figure lis a view of both the mechanical and electrical elements of the fuel injection system of the invention, showing vthe mechanical or pump :element in `cross-section and the electrical 'system .diagrammatical1y.

vFigure 2 is afragmentary, cross-sectional View vvof the topportion roi the pump'element, showing an alternative structure for regulating the air 'pressure fat lthe head ofthe pressure regulator cylinder.

Referring now to Figure l vof the drawings, valpuinpelement vl isiformedina housing 2, which Ais .'suitably bolted to the framework of the en- 1l. "The piston is `normally urged Vdownwardly by a coil vspring I2 encircling the .lower end of the piston and compressed between the -pump Ahousing and a retainer i3 formed on the lower end 'of :the piston. The piston lil is reciprocated fin the usual manner by a cam lll having a high v-poifnt 'l5 and keyed to a cam shaft I6 which, in

turn, is loperatively connected to 'thefcrank shaft of the engine (not shown). The pump is `also :provided in lthe :usualmanner lwith a fuel supply line "-20 containing a check valve 2|. The valve A2| is normally held in closed position against fthe pressure of 'the fuel by a coil spring 22 en- =circling the Valve stem and compressed between 'the valve head and a plug 23 in threaded enrfgage'ment with the "pump housing. The pump e `or lmanifold vin the usual manner.

`The pump proper, identiie'dr :generally las 3,.'is shown as a conventional high ipressure,reciprocating iu'el injection pump 'corn- VVprising apiston lIll reciprocablewithin a cylinder vthe supply line 28 to the engine.

constructed of iron or other suitable material of high magnetic susceptibility, and depending from and secured to the regulator piston is a displacement piston 48 which is reciprocable within the displacement measuring cylinder 36. The regulator piston 39 is normallyT urged downwardly to a closed position, as shown, so as to bear against a washer 4|, by a coil spring 42 compressed between the top of the regulator piston 39 and the head of the measuring cylinder 35. An adjusting screw 43 is provided at its lower end with a spring retainer 44 to bear against the coil spring 42, and with a lock nut 45. By loosening the lock nut 45, the tension of the coil spring 42 can be adjusted as desired. The regulator piston 39 is provided with longitudinal ducts 46 for return of oil or fuel which may leak into the space above the piston.

A fuel duct 50 is formed in the pump housing, and a branch duct leads therefrom to a recess 52 formed in the housing and closed off at its lower end by a plug 53. A port 54 communicates the recess 52 with the displacement cylinder 3B. The port 54 is normally closed by a check valve 55, which is urged downwardly into closed position by a coil spring 56 encircling the valve stem and compressed between the pump housing and a retainer 51 secured to the lower end of the valve stem.

It will be seen that, when the pressure in the space above the regulator piston 39a rises above a predetermined value, the piston |54 will be urged upwardly to align the slot |56 with the duct |51, thus allowing escape of air; and that when such pressure falls below a predetermined value, air will enter the regulator cylinder 35 through the check valve |61.V

Mechanically, the operation of the fuel injection system, thus far described, is as follows: Fuel is supplied to the engine in the usual manner through the supply line 28, check valve 2|, pump cylinder feed duct 24, check valve 25 and feed line 28. With the regulator piston 39 closed as shown in Figure 1, a maximum amount of fuel drawn into the pump cylinder on the downstroke of the piston will be pumped through However, the downward forces exerted on the regulator piston 39 by the coil spring 42 and the solenoid 38 are opposed by the pressure or force of the pump piston I0 on its upstroke, this opposing pressure being transmitted to the displacement and regulator pistons 48 and 39 through the liquid fuel in the ducts 58 and 5| and the recess 52.

During the return or downstroke of the pump piston l0, the downward forces exerted bythe fcoil spring 42 and the solenoid 38 will be unopposed, thus returning the regulator piston to a lower position. The displacement piston 40 thus tends to reciprocate with the pump piston Hl. It will thus be seen that, depending upon the balance of downward forces exerted by the coil spring 42 and the solenoid 38 and the upward force of the pump piston I0, more or less fuel drawn into the pump cylinder on the downstroke will be merely pumped back and forth, or recirculated between the pump cylinder |U and the displacement cylinder 36 via the ducts 58 and 5|. The proportion of fuel intake thus recirculated is, of course, not effective in operating the engine. It will also be apparent that a maximum of fuel is supplied to the engine when the downward forces of the coil spring 42 and the solenoid 38 are greater than the maximum pressure of the pump piston I0 so as to maintain the regulator piston 39 always in closed position. Conversely, the more greatly the pump piston pressure exceeds the combined springand-solenoid pressure, the less fuel will be supplied to the engine. The means of regulating the relationship between these opposed forces will now be explained in detail.

The main elements of the electrical control or governing system are a conventional battery 65, starting relay 66 and motor starter-generator 61; a governor generator 68, any desired number of speed regulating relays 69 and the solenoid coil 38 referred to above. As shown in Figure l, and for purposes of varying the speed and power output of an engine employed in a vehicle or the like, there is provided a manually operable rheostat 10 for varying the speed and power output of the engine. It will be obvious, however, that for purposes of a stationary engine intended to operate, say, at constant speed, the rheostat 10 may be eliminated.

The starting relay 66 is provided, in the usual manner, with contact elements 1|, a closing coil 12 and a holding coil 13, and the starter-generator 61 is provided in the usual manner with an armature 14, a commutator field winding 14a and a field winding 15. Likewise, the governor generator 68 is provided with a field winding 16, an armature 11 and a commutator eld winding 11a. Each of the speed regulating relays 69 is provided with contact elements 18, a closing coil 19 to close the contact elements and a dropout coil 80, wound in opposition to the closing coil so as to urge the contact elements 18 to open position.

The rheostat 10 is enclosed in a housing 84 of any suitable electrically conducting material, and it is provided interiorly with a resistor having spaced contact buttons 88 carried by a shelf 81 supported Within the housing as shown. A slide rod 88 is provided, to which is secured a contactor 89 formed of spring metal. The slide rod 88 is also provided, as shown, with a stop collar 90, a coil spring 9| to urge it outwardly, a head 92 to compress the spring 9| and provide a lbearing surface for the operators foot or hand,

and a ground ribbon 93 secured at one end to the outer end of the slide rod and at its opposite end to vthe rheostat housing at 94. The rheostat housing 84 is also provided with insulation bushings 95.

The circuits involved are as follows: The usual battery-generator circuit is employed, the battery 65 being connected'by its negative terminal to ground through a lead IDI and by its positive lterminalthrough a lead |02', a main switch |n4 and a lead |05 to the closing coil 12 of the "start- Vfirxgrelay Also, asin thensuallrcuit, the

opposite terminal yof the closing 4coil is l'connected through a lead |06 to ground, and 2a push 'button switch lllllzisrpronided 'inatlxezlead delig; 4the holding :coil .TSLiscQnnected tonne terminalcof fthe l contact element theopposite terminal Lofzwhichzisrconne'cted itoth'e yleazl |195, as shown; the opposite terminal of the .holding ico'il "I3 Lis connected -through'a lead |98Ito the;fle1`fl'winding A'1:5 .of the starter-generator 9:1 (also 'to thereld winding 18 of the governor generator 88 for afpnrplose explained hereinafter); .and the commutator field Winding 14 is connected by y.leads |09 and ||0 to the contact element 1| and by a lead to ground, as zshown.

contact elements are .connected lin parallel, by

leads l, to-a `voltage proportioning resistor |.|8,

'Branch leads ilflconnec't the resistor ||L8 with a llead |29, :which connects .with one terminal of the solenoid coil 38. The opposite terminal of the solenoid is shown as being connected by a lead |2| to ground, but it is obvious that, instead, the lead |2| may connect with a second solenoid coil housed in a second pump unit, and that any desired number of pump units, each having a solenoid coil, may be connected in series.

It will be apparent that, when the main switch |94 is closed, current will tend to pass through the lead H6, the relay contact elements 18, etc., to the solenoid coil 38. Normally, however, the contact elements 18 are open. as shown, and the means provided for closing them to energize solenoid, is as follows: A lead |25, shown as containing a fuse |26, is connected to one terminal of the rheostat resistor 35, and a lead |21 connects the opposite terminal thereof, with one terminal of each of the closing coils 19 of the speed regulating relays 69. The opposite terminals of these closing coils are connected to ground, as shown.

It is thus apparent that, when the main switch |04 is closed, current will pass through, and will energize the closing coils 19, thus closing the contact elements 18. It is also apparent that the parallel rheostat circuit shown. through the contact buttons 86, contacter 89. slide rod 88, ground ribbon 93, rheostat housing 84 and a ground lead |29, will govern the supply of current to the closing coils 19, hence will control their degree of excitation and their tendency to close the contact elements 18. With the slide rod 88 in retracted position as shown, the least current will iiow through the closing coils 19, and in advanced positions thereof, proportionately more current will now through said coils.

Opposed to the closing coils la are the dropout coils 30, whose circuit is as follows: The field winding 'l5 of the governor generator 68 is excited by current through the lead |08, and a ground lead |39. One terminal of the armature `Winding is connected in parallel to a terminal of each of the dropout coils 80 by a lead |35 and by leads it, each of which. contains a variable re* sistor |31'. The opposite terminal of each dropout coil is connected by a lead |38 to a common lead |39 containing la variable resistor |40, the lead |39 connecting with the opposite terminal of the armature winding 11.

It .is thus apparent that a solenoid energizing circuit is provided. embodying the relay closing coils 19 and the relay contact elements 18 actu ,rated 'bythe fclosing coils; that ,asolenoid cie-energizing circuit ris Valso jprovided, :embodying the `igor/ferner generator .6B :and .the dropout coils 8|), which :oppose the closing coils .19 and Vtend tto :openithe :contact elements 18; Vandpthat, depending upon the fbalancesbetweenthese ,circuits,zmore 'or less `errergfization of .-theisolenoid coil fdl.. hence more :or less 'supply of fuel to the engine, is 'provided. -illlie.individual variable resistors |31 will be pre-adjusted .to cause opening and closing .of the :contactfelements 1=8 .in any desired sequence, while #the :single variable L.resistor M9 common `to the `whole de`energizing circuit is `provided to prevent burningout of the dropout coils 8U.

E1n operation, land with the yrheostat 1B lat .a rgivensetting, as `the loadon the enginezincreases, 'lth'e fspeed lof f the .governor f generator 68 will ltend to lfslacken, 4lhence fthe de-energizing circuit will Yopposev the energizing' circuit to a lesser degree and `willfre'sult inthe closing of one or more open Icontact elements :18. This overly compensates ffora .weaker current :from the starter-generator `267|,ilience energizes the solenoid coil 38 to agreaterfdegree. lThis, in turn, will result `in a greater fuel supply to the engine to compensate for the greater load. It will be apparent that the governing effect of the de-energizing circuit will operate in reverse as the load is decreased, to supply less fuel to the engine to maintain constant speed under the lighter load.

It is thus apparent that a fuel injection system has been provided which accurately and rapidly adjusts the fuel supply in accordance with load requirements, and that adjustable or variable fuel pump elements have been minimized.

While I have shown the preferred form of my invention, it is to be understood that various changes may be made in its construction by those skilled in the art without departing from the spirit of the invention as dened in the appended claims.

I claim:

l. A fuel pump system for an internal combustion engine, comprising a fuel pump operable by the crankshaft of an engine and including a fuel pump cylinder and a fuel pump piston reciprocable therein, a fuel displacement pump including a displacement cylinder and a displacement piston reciprocable therein, means communicating said cylinders whereby fuel may be recycled between said cylinders on reciprocationl of said fuel pump piston, means including a solenoid coil for urging said displacement piston to closed position, and means including a solenoid energizing circuit and a solenoid de-energizing circuit responsive to engine speed for controlling said last mentioned means and governing the stroke of said displacement piston.

2. In a fuel pump system for an internal combustion engine, comprising a reciprocating fuel supply pump, a reciprocating fuel displacement pump, means communicating said pumps to reciprocate said displacement pump and displace fuel by recycling between said pumps, the improvement which comprises electrical means associated with said displacement pump to control and vary the stroke thereof,l and an electrical circuit responsive to engine speed for varying the energization of said electrical means.

3. A fuel pump system for an internal combustion engine, comprising a reciprocating fuel supply pump, a reciprocating fuel displacement pump including a displacement piston, means v communicating said pumps whereby reciproca tion of said Supply pump tends to cause reciproycation oi said displacement pump andrecycling Vof fuel between said pumps, a. solenoid coil operable to urge said displacement piston to closed position, an electrical circuit for energizing said coil and an opposed electrical circuit responsive i to engine speed for de-energizing said coil.

4. The system of claim 3, wherein said energizing circuit includes and is operable to close a contact element and said de-energizing circuit is operable to open said contact element.

de-e'nergizing circuit, said de-energizing circuit being responsive to engine speed and acting in opposition thereto.

6. The system of claim 5, wherein said electromagnetic means is a solenoid coil, said energizing circuit includes a plurality of relay contacts, and co-operating relay closing coils, and said deenergizing circuit includes a generator operable by the engine crankshaft and a plurality of dropout coils complemental and opposed to said closing coils.

PATRICK C. WARD.

REFERENCES CITED The following references are of record in the le 'of this patent:

UNITED STATES PATENTS Number Name Date 1,059,604 Gaif Apr. 22, 1913 1,678,398 Lange July 24, 1928 2,019,321 Sass et al. Oct. 29, 1935 2,144,132 Walti Jan. 17, 1939