US2598147A - Fuel feeding system - Google Patents

Description

May 27, 1952 G. l.. TEscHER FUEL FEEDING SYSTEM 2 SHEETS-SHEET l Filed DeG. 30, 1949 QM, MW..

@075072 .acia e?? 1m/ww May 27, 1952 G. TEscHER FUEL FEEDING SYSTEM 2A SHEETS-SHEET 2 Filed Dec. 50, 1949 astartlng'supply'of'fuelL Patented May 27, 1952 FUEL FEEDING SYSTEM Gordon. L. Tescher, Anderson, Ind., assigner t'o Tescher Corporation, Anderson, Ind.

Applicationecember 30, 1949, Serial No. 136,072

This invention. relates to new and useful im-L vprovements.v in fuel feedingY systems andA particularlyI- toffuelifeeding. systems for internal Vcomhnstionr.engines;`

It is. an object of this-invention tol provide a;

simplified fuel feeding system for internal combusticn engines;

It. is ai-further object` of this. invention. to vpro-- vide-.ae fuelzfeeding system which Will not create an unduly high back pressure on the: engine.

Vllt;isan;obiectof this invention to. provide a simplified. fuel: feeding. systemi which is particularly'adaptedifor usefwithtwo cycle internal-combustioniengines;

A: further object :of this invention is to provide -l tion withthe crankcaser and operatedv by the yalternatingv positiveandmegative crankcase' pres- 'suresrof the engine, thuseliminating connecting conduits-and weighty and-complicated operating linkages..

Stilllanother oliijectfof the presentinvention is to provide a fuel feeding system wherein the .fuel is. deliveredr to the carburator by the fuel pump at. a predetermined.. uniform, maximum pressure: regardless. oftlie. speedof the engine.

VAnother object of the present invention. is to .provide afuelfeedingsystem wherein. the fuel pumpds. provided with a lspring biased,- by-pass means. whichrelieves pressure on the' enginecarlru'isator. when. a predetermined maximum fuel Dressurelias beenreached'.

'Another object` of" this. invention is. to. provide ai'firelfeedingsystem wherein the fuel from the fuel"I is delivered to an auxiliary gravity taxik'abovethe-carburator, thi'sreserve tank having; overflow" and by-pass means communicating withthem'ainfuel tank for the purpose of relievingexc'ess'pressurein'the'carburator and controllingthe amount of. fuel inthe auxiliary tank byfretnrmng' excess fuel lifted by. the. pump to the main tank, said.' auxiliary tank also" providing 6 Claims. (Cl. 12S-139) Another object of this invention is to provide a simplified and improved diaphragm fuel pump principally for use in fuel systems of internal combustion engines but whichmay be adapted to any application wherein it is desired to pump a fluid by means of pulsating fluid pressures.

With the above and other objects in viewas will be presentlyapparent, the invention consists in general of certain novel details of construction and combinations of parts hereinafter fully described, illustrated in the accompanying drawings and particularly claimed.

In the accompanying drawings,.like characters of reference indicate like parts in the several views,and:

Fig. 1 is a side elevational view, partly in section and partly broken away, showing the simplified and basic form of the fuel feeding system forming the present invention, the same being used in conjunction with a standard one cylinder, two cycle. gasoline engine,

Fig. V2 is a cross-sectional view taken on the line 2'-2 of Fig. 1,

. Fig. 3 is a side elevational view, partly in sec-I tion and. partly broken away, showing a modified form of fuel feeding system as applied to the same type of engine, and

Fig. 4 is a cross-sectional View taken on the line 4--4 ofFig. 3.

In Figs. 1 and 2 of the drawings are shown the simplified and basic form of the fuel feeding system of the present invention.

In the design and construction of the small two cycle gasoline engine the governing factors are lightness, simplicity, compactness and the need for the minimum number of moving parts. It is apparent, then,.that the invention as shown in Figs. 1 and 2 of the drawing is of special importance in the art due tov itsv simplicity.

With the exception of that portion of the cylinder Wall upon which the fuel pump ismounted, the engine shown herein is 'of standard construction.

Referring now to Fig. 1, the numeral I6 designates the cylinder head of the engine and the reference numeral Il the crankcase thereof.

Reciprocatingwithin the cylinder head l0 is'the piston head l2 and'linking the piston head l2 to the crank shaft I3 are the piston rod I4 and wrist pin. Mb. Cast into the' lowerside portion ofthe cylinder head isr an elongated channel |5 which leads from the exhaust port IB inthe cylinder bore to an exterior opening l1 for exhausting the products of 'combustion to the atmosphere. Cast into the upperside of'thecylinder head* I0 is an elongated channel I8 which connects an aperture I9 in the crankcase with an intake port 29 in the cylinder bore. On the outer end of the crankcase I is the standard carburator 2i which discharges into the crankcase thru the aperture 22. At the inner end of the cylinder head is the standard sparkplug 23.

Ihe fuel tank of the engine is represented by the numeral 24 and leading to the intake side of a fuel pump 2B is the conduit 25. A conduit 25h carries the fuel from the exhaust side of the fuel pump to the carburator 2 I.

For seating the fuel pump 26, the face of the cylinder head casting exterior of the elongated channel i8 is formed with a planar and generally circular face 21 which is machined to a smooth surface. Concentrically placed in the face 21 and communicating with the elongated channel I8 is a relatively large circular aperture 28.

The fuel pump 26 is formed of three circular sections, the lowermost section being designated by the reference numeral 29. This disc shaped lower section 29 has a planar lower face 39. The upper face 3i is planar for a short distance inwardly from its peripheral edge and then drops downwardly in the form of a circular, concave depression 32. formed a small hole 33, the lower part thereof having an enlarged bore as at 34 to form a shoulder, the purpose of which will be later described. Spaced on either side of the vertical axis of the lower section 29 and extending thru said section are a pair of ports 35.

Overlying the lower section 29 and of the same diameter as the section is an elastic diaphragm 36. Transxing the center of the diaphragm 35 is a bolt 31, the upper end of which is reduced in diameter to form a shoulder 38, and the upper end of said reduced section being threaded to receive a. nut 39. Between a shoulder 38 and the nut 39 are clamped the diaphragm 35 and two clamping washers 45. The lower end of the bolt 31 has fastened thereon, by a cotter pin. or am7 othersuitable means, a washer 42. Positioned on the bolt 31 above the lower washer 42 and seated in the enlarged bore 34 is a coil spring 43 which resists compression and which, when the diaphragm 32 is moved upwardly by a pressure pulse, returns it to a neutral position when the pulse has passed.

Immediately overlying the diaphragm 3E in clamping relation with the lower section is a discshaped intermediate circular section 44 of the same diameter as the lower section 29. The lower face of said intermediate section has concentrically formed therein a vertical walled chamber 45 of suihcient depth to permit clearance of the diaphragm assembly when it is moved upwardly its maximum distance by the crankcase pressure.

Overlying the intermediate section 44 and of the same diameter is a disc-shaped top section 41B, and between the sections is placed a gasket 41. For drawing the sections of the pump together into huid tight relationship there are provided near the peripheral edge of the disc sections a set of spaced bolts 48. the lower ends of which threadedly engage internally threaded sockets in the lower section 29. For securing the pump to the machined face 21 and also to aid in drawing the pump sections into a fluid tight seal are the spaced bolts 49, which are threaded at their lower ends to engage internally threaded sockets 50 in the cylinder casing.

In order to receive and discharge fuel, inlet At the center of the section 29 is and outlet chambers 5I and 52 are provided, these being relatively deep, approximately semi-circular recesses having vertical side walls, the portion of the top section 46 between the recessed chambers 5I and 52 forming a rib 53 separating the two chambers. On either side of the rib 53 and thru the side wall of the top section 46 are threaded openings 54 and 55. In the opening 54 is positioned the end fitting 5B of the pump supply conduit 25 and in the opening '55 is positioned the end fitting 51 of the discharge conduit 25h. In order to provide fluid passage from the inlet chamber 5I to the diaphragm chamber y44, a port 58 is formed in the intermediate section 44. Over the lower end of this port 58 and secured to the intermediate section 44 in any suitable manner is a flap valve 59. A similar port '6D leads from the diaphragm chamber 44 to the outlet chamber 52 as shown. and over the upper end of said port is a flap valve 6| secured in any suitable manner. s

While the inlet and outlet valves 59 and 6I are herein shown to be flap valves it is to be understood that any form of spring biasedv valve may be used and still have suitable operation ofthe pump.

In order to describe the operation of the fuel feeding system it is necessary to briefly outline the operation of the two cycle engine shown in the drawings. f

As shown in Fig. 1, the piston I2 has just reached the top of its stroke, and compressed a charge of atomized fuel and air in the cylinder head. At this point the charge is fired by the sparkplug 23. The piston I2 movesoutwardly toward the crankcase II and in so doing compresses the air and gaseous fuel mixture in the crankcase. This pressure likewise builds up in the elongated channel I8. When the piston moves far enough to uncover the ports I6 and 20, the products of combustion pass thru the exhaust port I6, channel I5 and exterior opening I1. At the same time pressure in the channel I8 forces a fresh charge into the cylinder head. The piston at this point reaches the bottom of its stroke and moves inwardly covering the ports. As the piston progresses inwardly it forms a partial vacuum in the crankcase II and channelV I8, this negative pressure causing a fresh mixture of air and gaseous fuel to be drawn into the crankcase. The engine is then ready for a new firing stroke.-

It will thus be noted that the channel I8 is subject to alternate positive and negative vpressure pulses, the positive pulse greatly exceeding the negative pressure.

When a negative pressure occurs in the channel I8 the space below the diaphragm is also evacuated and the diaphragm moves downwardly. This reduces the pressure in the inlet chamber and fuel is forced by atmospheric vpressure up the fuel supply line 25 and intothe inlet chamber 5 I, the flap valve 59 moving downwardly to' permit the fuel to ow into the upper diaphragm chamber 45. When the heavy positive pressure pulse occurs in the channel I8 the diaphragm assembly moves upwardly compressing the fuel in the upper diaphragm chamber 45 and also compressing the ft may be'notedthat in this form of theinvention'v the engine must bel turned over a number of times mechanically' or a charge-must be mechanically placed in the carburator so that the engine will operate untilair in the fuel feeding systemy has exhausted and fuel reaches the carburetor. It may be further noted that the'pressure-in the fuel'feedline to the carburetor increases approximately in direct ratio to the engine speed.

The extreme simplicity of this form of the invention is to be emphasized, no moving parts other than the diaphragm being required, with the complete elimination of all pump actuating cams and gears. This extremesimplicity is highly desirable in some engine applications.

In Figs. 3- and 4 of thedrawings are shown a modified form of the invention, incorporating a pressure relief valve in the fuel-pump 26 wherein when a predetermined maximum pressure has'v 4all parts of the construction not modified are indicated by the reference numerals designated above.

The modification of the fuel pump consists of changes made in the circular top section now designated by the reference numeral 46a. As in the previous form the top section has formed- 'therein the inlet chamber 5la and outlet cham ber 52a with the rib 53a separating the two chambers. In the side wallsl of the top section 46a and on either side of the rib 53a, axially aligned at right angles to said rib, are the threaded' ports 54a and 55a. The threaded port 54a is enlarged, as shown, to receive the threaded bushing 54h,

for a purpose hereinafter described. Threaded in thefbushing 54h is the end fitting 56a of the fuel conduit 25.

Axially aligned with the ports 54a and 55a and in the rib 53a, is a threaded opening 62. Positioned in this opening is a pressure relief valve designated in general by the reference numeral 63.

The valve 63 consists of a tubular body portion 64 having one end outwardly threaded as at 65. This end of the tube 64 is also provided with a reduced bore 66 which terminates inwardly in a spherical recess 61 forming a seat for a ball 68. The opposite end of said tube is closed with the exception of the relatively small slotted opening 69. This end of the tube is slotted as at 1l] to provide a means for rotation of the tube for removal, said slot being aligned With the opening 69. A coil spring 1| of predetermined strength is compressed between the ball 68 and the opposite end of the tube. It will thus be seen that if the bushing 54h is removed a turning tool may be inserted thru the opening 54a for removal of the valve 63.

Between the outlet chamber 52a and the carburetor, if desired, may be placed the auxiliary gravity tank 12. The conduit o entering the bottom of the tank has an upwardly directed extension 14. Also from the bottom of the tank 'I2 extends a return tube 14 which empties into the top of the fuel tank 24. This tube 'I4 has an upwardly directed extension 'l5 which reaches nearly to the top of the tank l2. A

6 conduit` 'I6 connects. the bottom voff-the gravity tank to the carburetor 2l".

In operation' the modified system has several advantages if simplicity. is notthe primary factor. Those familiar with the art willv appreciate that it is desirable not to maintain a pressure greater than'necessary to supply the engine with adequate quantities of fuel,. since any excessof pressure produces unnecessary andundesirable vback pressure on the automobile engine. --When which willserve until the pump begins tolmove fuel into the auxiliary tank. The fuel line 14 and its extension serve as an` cveriiow return means to the main tank Edwin! vcase the pump 26 delivers an excess of fuel; Thisbypass return also prevents accumulation of pressure in the carburetor andthe by-pass valve 63 then servesonly as a release for excess-pressure in the outlet chamber 52 if it builds up more rapidly than it can be relieved by the fuellin-ezc.

While the present fuel feeding systemv inits preferred form is shown as applied to a one cylinder, two cycle engine, it isto be understood that it could be appliedwith minor changes in the system or in the engine` design to multiple two or four cycle internal combustion engines, without departing from the spirit andY scope. of the invention as claimed.

What is claimed is:

1. In a fuel feeding system for interna-l combustion engines and in combination with an engine, a fuel tank, a fuel pump associated-With said engine and operated by alternatingpositive andnegative pressures inthe crankcase thereof, and conduit means for carrying fuel from the fuel tank to said pumpand from` the pump to the carburetor of the engine, said fuel pump having spring biased, by-pass valve means associated therewith whereby fuel pressures in excess of a predetermined maximum at the outlet of said pump will be relieved to the inlet side of said pump to thereby prevent the accumulation of excessive pressures in the carburetor of the engine.

2. In a fuel feeding system for internal combustion engines and in combination with an engine, a fuel tank, a diaphragm fuel pump assoelated with said engine and operated by alternating positive and negative pressures in the crankcase thereof, and conduit means for carrying fuel from the fuel tank to said pump and from the pump to the carburetor of the engine, said fuel pump having spring biased, by-pass valve means associated therewith whereby fuel pressures in excess of a predetermined maximum at the outlet of said pump will be relieved to the inlet side of said pump to thereby prevent the accumulation of excessive pressures in the carburetor of the engine.

3. In a fuel feeding system for internal combustion engines and in combination with an engine having an opening in the wall thereof, a fuel tank, a diaphragm fuel pump mounted directly on the wall of said engine in iiuid tight relationship therewith and positioned over said opening, said pump being in communication with the crankcase of said engine whereby alternating positive and negative pressures in the crankcase actuate the diaphragm of the fuel pump for the pumping of fuel, and conduit means for carrying fuel from the fuel tank to said pump and from the pump to the carburetor of the engine, said fuel pump having spring biased, by-pass valve means associated therewith whereby fuel pressures in excess of a predetermined maximum at the outlet of said pump will be relieved to the inlet side of said pump to thereby prevent the accumulation of excessive pressures in the carburetor of the engine.

4. In a fuel feeding system for internal combustion engines and in combination with an engine, a principal fuel supply tank, a fuel pump associated with said engine and operated by alternating positive and negative pressures in the crankcase thereof, an auxiliary gravity fuel tank positioned so as to be above the carburetor of the engine and holding a relatively small amount of fuel. conduit means for carrying fuel from the principal fuel supply tank to the fuel pump,

conduit means for carrying fuel from the fuel pump to the auxiliary fuel tank, conduit means from said auxiliary fuel tank to the carburetor of the engine and an overfiow and return conduit means having an opening positioned near the top of said auxiliary fuel tank and leading into the top of the principal fuel supply tank for relieving excess fuel and pressure produced in said auxiliary fuel tank by the fuel pump.

5. A fuel feeding system as set forth in claim 4 wherein said fuel pump has a spring biased, bypass valve means associated therewith whereby fuel pressures in excess of a predetermined maximum at the outlet of said pump may be relieved to the inlet side of said pump thereby to prevent the accumulation of excessive pressures in the carburetor of the engine.

6. In a fluid pressure operated pump, a lower circular disc having a recess in the upper face thereof and at least one aperture therethrough for admission of an operating fluid; an intermediate circular disc of the same diameter as .and a pair of spaced apertures providing fluid passage from said circular recess to the upper face of said disc; a flexible pumping diaphragm clamped between said lower and intermediate `circular discs; a flap valve attached to the upper face of said intermediate disc and overlying one of said spaced apertures and a second flap valve positioned over said second spaced aperture and attached to the upper wall of the recess in said intermediate circular disc; an upper circular disc of the same diameter as and overlying said intermediate circular disc and having a pair of arcuate recesses formed in the lower face thereof and spaced so as to leave a separating partition, thereby forming the upper and side walls of separate fluid inlet and outlet chambers, each of said chambers having a fluid access opening in one of said walls; and means for simultaneously securing said overlying discs in uid tight relationship, said separating partition having a threaded aperture therein, a tube having an exteriorly threaded open end engaged with said aperture and a spring biased valve element within said tube and normally closing said open end, the opposite closed end of said tube having a slotted opening formed transversely thereof to thereby serve both as a fluid access to the valve and a tool engaging slot for seating or removing the valve structure.

GORDON L. TESCHER.

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

UNITED STATES PATENTS Number Name Date 434,171 Baldwin Aug. 12, 1890 1,639,623 'White Aug. 16, 1927 1,999,520 Stout Apr. 30, 1935 2,146,398 Lafferty Feb. '7, 1939 2,242,582 Jencick May 20, 1941 2,389,159 Lowther Nov. 20, 1945

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