US2311939A - Fuel pump - Google Patents

Description

Feb. 23, 1943.

G. C. GOODE ET AL FUEL PUMP Filed Feb. 6, 1939 2 Sheets-Sheet 1 A I E :9 7 66 7a 6 o 6 7 INVENTOR.

GIL-BERT c. @0005 m WILLIAM F! HARR/umvM ATTORNEYS.

b, 1943- G. c. 60005 ETAL A. 2,311,939

FUEL PUMP .Filed Feb. 6,1939 2 Sheets-Sheet 2 INVENTOR. GILBERT GUODE 'mvp w/L 1 mm E" HflRRI/YGTOM ATTORNEYS.-

Patented Feb. 23, 1943 Gilbert Geode, Bir

Harrington, Detroit,

tion of Delaware mingham, and William F. Mich; assignors to Chrysler Corporation, Highland Park, Mich, a corpora- Application February 6, 1939, Serial No. 254,832

1 Claim.

This invention relates to an improved fuel pump for fuel injection engines.

One of the main objects of the invention is to provide a pump of this character which will supply fuel under pressure to all of the cylinders of a multiple internal combustion engine in a predetermined timed sequence.

Another object of the invention is to provide separate fuel displacing elements in a pump of this character which remain bodily fixed during operation and which do not require such bodily displacement of the mass of its parts as would limit its speed of operation.

A further object of the invention is to provide diaphragm fuel displacing elements in a pump of this kind which are adapted to be actuated by and under the control of a single cam member.

A still further object of the invention is to provide means in a diaphragm type fuel pump by which the quantity of fuel displaced per operation of the diaphragm and the time relationship between the discharge and crankshaft position may be selectively varied and predetermined.

Other objects of the invention are to provide actuated members for the fuel displacing means which operate in paths readily arranged from a common axis; to provide an improved driving cam for such actuating members which is so constructed and arranged as to gradually vary the lengths of the strokes thereof throughout substantially wide limits; to provide a cam operated member of this kind which is readily removable and replaceable by a similar cam member-of a different contour; to provide means for shiftably supporting and shifting such a cam during operation thereof; to provide a pump of this character having a design which readily accommodates provision thereon of a plurality of diaphragm fuel displacing members in an arrangment such that they can be conveniently operated under the control of a single cam member; to provide externally mounted fuel displacing elements in a pump of this character which are independently securable to and removable from the pump casing; and to provide a positively sealed, simple and inexpensive fuel pump of this kind which is particularly adapted to discharge accurately metered small quantities of liquid fuel in rapid succession during high speed operation of a fuel injection engine of the self-priming, Diesel or ignition types.

An illustrative embodiment of the invention is shown in the accompanying drawing, in which:

Fig, 1 is a diagrammatic vertical sectional view of a fuel injection type engine equipped with "a fuel pump embodying the invention and illustrating the manner in which the latter is operated.

Fig. 2 is a central vertical vice." of the pump illustrated in Fig. 1.

Fig. 3 is a vertical sectional view taken on the line 3-3 of Fig. 2.

Fig. 4 is a horizontal sectional view taken on the line 4-4 of Fig. 2. 7

Fig. 5 is a horizontal sectional View taken on the line 5-5 of Fig. 2.

Fig. 6 is a fragmentary vertical sectional view taken on the line 6-6 of Fig. 3.

Fig. '7 is a fragmentary. vertical sectional view taken on the line 1-1 of Fig. 6.

Fig. dis a side elevationalview of the cam illustrated in Fig. 2.

Fig. 9 is a side elevational view of a cam similar to the cam shown in Fig. 8 but having a different contour.

In the form of the invention illustrated in the drawings, the improved pump is shown in combinationwith a fuel injection type engine, generally designated by the numeral I0, which includes a cylinderhearl portion II, having a combustion chamber I2 therein into which fuel is injected by a nozzle I3 communicatively connected through a conduit I4 with a pump generally designated by the numeral i5, embodying the invention. The internal combustion engine I0 comprises a crankshaft I6 having a pinion I1 thereon meshed with a timing gear I8 carried by a cam shaft I9. The cam shaft I9 has earns 20 thereon which operate the valve mechanism generally designated by the numeral 2 I.by which anintake valve 22 is operated in timed relationship with rotation of the crankshaft I6. It should be understood that the cam shaft I9 carries cams (not shown) which operate in a similar manner upon the exhaust valve mechanism (not shown) of the engine.

Rotatably mounted in the block structure 23 v erally designated by the numeral 26 in which are provided horizontally aligned concentric bear ing the shaft 32. q Formed on the exterior V V standingihousing portion 3| are substantially flat faces 39 which, in the illustration shown, are' substantially tangential to a circle having its lugs 21 and 23 for rotatably supporting a horizontal shaft 23. Provided on the left end oi the I shaft 29, as illustrated inFlg. 2, is a bevelled pinion to which isadapted to be meshed with the .pinion 25 of the gear 24 in order to drivingly rov tate the shaft 29 in timed relationship with re-' spect to the crankshaft I of theengine' The f pump housing 26 includes a vertically upstanding portion 3| in which is iournalledavertically extending shaft 32. The lower end portion ofthe Disposed in the outlet chamber 59 isfan outlet 'valve '50 which is adapted to 'be'op'enedby the pressure applied on the fuel in thecompression shaft 32 is rotatably supported by'a bearing 33.

and the upper end portion of the shaft 32 isprovided with splines 34 on whicha cam35 is slidably but non-rotatablylnounted. The upper end portion of the cam 35 is rotatably and shiftably: supported by a bearing 38 carried byan-lnverted cupshaped member 31 which is shiftably mounted in the cylindrical opening 38 formed in the upper extremity of the-housing portion 3|. The bearing 36 thus serves to cooperate with the bearing 33 in rotatably supporting and positionof the vertically uppression chamber 'fl. An'inlet valve II'disposed' in the inlet chamber 56 is provided for preventing a reverse flow of fuel through the inlet passage sections andv 54 during fuel displacing operations. The plate 55 is provided with an outlet port 53 which communicates with the compression chamber 41:-and with an outlet chamber 53 formed injthe headstructure 43.

chamber 41 and whichis'fiormally closed during the suction stroke of the diaphragm. A dis-- charge passage 6| leading from the discharge .i chamber 59 is communicatively connectedwith the conduit H by which liquidfuel is supplied- I to the nozzle |3of the fuel injecting system.

center at the axis oithe shaft 32. In 'a pump 'de.-' 7

'slgned for supplying fuel to a six-cylinder enj., gine, such as the pumpillustrated in the draw- I ings, there are provided six such flat faces 39,-as

illustrated in Figs. 4 and-'5,'in a hexagonal ar j rangement.1' I'h wall structure of the upstanding portion 3| is provided with a bohe 40 extending radially with respect to the axis of the shaft 32 and located substantially centrally of each of ed ideachbore 40 and provided with 'a head 42 the flat faces39. A plunger 4| is slidably mountwhich is receivable in a recess 43xformed substantially at the center of the flat faces 39;

Mounted onfeach of the flat faces 33 is a pump unit, generally designated by the numeral .44,

and since all the pump units are substantially identical, a description 10f one will serve forall.

Each pump unit includesa diaphragm 45 com-.

prising flexible sheet metal, material which is" "disposed adjacent the face 39Ion the housing of; ,the pump The marginal portions of the dia phragm 45' are firmly clamped against the face 39 by a' plate 48 having a recess 'on the side thereof adjacent the diaphragm which, together with the diaphragm, forms a compression chamber into which the central portion of the diaphragm '45 is adapted to be deflected for'dis-:

" placing fuel from the pump. The plate 46 is held upon the face 39 by a head structure 43 and by flbolts49 which extend through registeringapertures in'the head structure'and plate45' and which arethre'afded in apertures wall of the housing portion 3|. Fuel'issupplied to the compression chafmber "41 by a fuel inlet conduit 50 which communicates with a' passage 5| formed in thewall structure of the housing portion 3|. The lower end por- 'tioi of the passage 5|, as illustratedjin Fig.2,

communicates with a discharge passage'52 from which the compression chambers of each of the formed in the During operation of the fuelpump, the'camf: 35 and shaft 32 on which it is mounted are drivingly rotated by engaged bevelled pinions52 and 6.3 fixed on adjacent end portions of the shafts. 29 and 32 respectively; The inner extremitiesof each of the plungers 4| are yieldably held by the dlaphragms 45 with whichfthey respectively cooperate, in contact with the operativesurface of'the cam 35; Thus, each rotation of the cam causes eachof the plungersand associated di'aphragms to perform a fuel displacing stroke;

Since the cam is driven: in timed relationship with respect. to thecrankshaft of the engine,fthe operative strokes of the diaphragm occur in a. predetermined relationship corresponding to the firing order of the engine. v In the pump illustrated in Figs; 2 and' 8, the

cam as is provided with a raised'portion 64 which tapers from a minimum thickness at its upper, end to-a maximum thickness at its lower end.

This raised section, as illustrated in Fig. 8, is disposed diagonally with respect to its axis of rotation.- l

- The cam is is adapted to be shiftedrv ertically" within predetermined limitsas established b a stop; 65 by a throttle control. mechanism diagrammatically illustrated in; Fig. 2 as compris-y 7 ing'acrank iiipivotally mounted at 51 on the. upper end portion of the pump housing part'3l.

I The crank 66. has a lever 53"operativelyfcon-r nected; with: a throttle valve by which the crank may be rotated about its axis; The crank '56 alsohas a lever 10 which is pivotallyfconnected by a link 1| with the inverted cupshaped shiftable l support 3|.- Clockwise. ,rotation of the crank '66; by the rod 59 causes the support 3'! and cam 35 to be lifted and counterchambers ,41. When the-cam contour corresix pump units are supplied with fuel. The head structures 48 of each of the pump units 44 and 'the plate 48 thereof are provided 'with communicating' fuel inlet passage sections 53 and 54 which communicate with the distributing 'passage 52' through a port 55"formed in the wall 7 structure of' thehousing portion 3|." The fuel inlet passage section 53, communicates with an inlet chamber 56 which in turn leads to the comclockwise rotation of the crank causesthe sup- 1 7 port 31 and-.cam to. be lowered. The n as the cam 35. is lifted vertically, portions of the raisedpart thereof of greater thickness come i into operative engagement with'theplungers 4|,

thereby increasing. the strokeof' the plungers. l

and correspondingly'increasing the quantity of discharge of liquid fuel from thecompression spondsfto thatillustrated in Fig.8 and the, cam

" is driven in a clockwisedirectionas viewed from p the above in. Fig. 2} the time 'of Qdischar'ge of fuel with respect to crankshaft position is reftardediand the duration ofthedischarge'period is increased. When thecam 35 is lowered; the

quantity of fuel discharged pe'rstroke of each plunger 4| is decreased and thetime ofits occurrence with respect to crankshaft position .is 7 advanced while the duration period is decreased;

g If it is desired to c nge the enect or in-" of the discharge 7 creasing the quantity of fuel discharged per stroke upon the timing of the fuel discharge, the cam 35 may be conveniently substituted by a. cam 35' having a raised portion 64' such as that illustrated in Fig. 9. The raised portion 64' increases from a minimum thickness at its upper end to a maximum thickness at its lower end but in place of being inclined with respect to the axis of rotation of the cam, it is symmetrically dispcsed with respect to a vertical plane of the axis. The line 12 of initial contact between the raised portion 64 and the plunger H is inclined with respect to the axis of rotation of the cam but in a direction opposite to the line of initial contact 13 of the raised portion 64 of the cam 35 and therefore, as the cam is lifted to increase the quantity of discharge per stroke of each diaphragm, the time of occurrence of discharge with respect to crankshaft position is advanced and the period of duration of discharge is increased. When the cam 35' is lowered to decrease the quantity of fuel discharge per stroke the time of occurrence in discharge is retarded and the duration of the discharge period is decreased.

' The foregoing fuel pump is particularly adapted for the rapid discharge of small, accurately measured quantities of fuel such as is required in high speed operation of fuel injection systems for internal combustion engines. No bodily movement of the -fuel displacing element takes place since the central portion of the diaphragm deflects and therefore problems arising by reason of the inertia of 'parts of the fuel displacing element are avoided. The compression side of the fuel displacing element is positively sealed against leakage and no sliding seals such as are present in piston type displacing mechanisms are involved. The control ofboth the quantity and time of the discharge of fuel is extremely flexible and'capable of being graded with precision throughout a predetermined range while variation in both the time and quantity of discharge ranges may be conveniently made by merely substituting one cam member for another.

Although but several specific embodiments of 5 the invention are herein shown and described,

it will be understood that various changes in the size, shape and arrangement of parts may be made without departing from the spirit of the invention.

We claim:

A fuel pump including a casing having a central passage and a communicating radial bore, a plunger in said bore, an intermediate plate disposed adjacent an external surface of said casing having a recess therein registering with said plunger, and having inlet and outlet passage sections extending through its thickness, an outer plate member having an inlet passage section registering with but of smaller cross section than the inlet passage section of said intermediate plate and an outlet passage section registering with but of larger cross section than said outlet passage section of said intermediate plate member, inlet valve means in the inlet passage sections of said intermediate plate member engageable with the inner side surface of said outer plate member, outlet valve means in the outlet passage sectionof said outer plate member engageable with the'outer side surface of said intermediate plate member,

a diaphragm extending over said recess abutting u said plunger and having its marginal portions clamped between said intermediate plate member and said casing for displacing fuel from said recess, means detachably holding said plate members and said diaphragm in sealed relationship, and operating mechanism in said central passage engageable with said plunger for actuating said diaphragm.

GILBERT C. GOODE.

WILLIAM F. HARRINGTON.

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