US2469117A - Fuel supply for opposed cylinder engines - Google Patents

Description

May' 3, 1949. E. c. KIEKHAEFER FUEL SUPPLY FOR OPPOSED CYLINDER ENGINES Filed March 9, 1946 4 Sheets-s l May 3, 1949. E. c. KIEKHAEFER FUEL SUPPLY FOR OPPOSED CYLINDER ENGINES Filed March 9. 1946 4 Sheets-Sheet 2 r 2 W m a a mm 5 r 7% N F 4 f N Z May 3, 1949. E. c. KIEKHAEFER 2,469,117

FUEL SUPPLY FOR OPPOSED CYLINDER ENGINES Filed March 9, 194a 4 Sheets-Sheet :s

IIIIIII [in 012102 3 Elmer 6. Z'Mfiae/r v 7 J/I orney May 3, 1949. E. c. KIEKHAEFER FUEL SUPPLY FOR OPPOSED CYLINDER ENGINES Filed March 9, 1946 4 Sheets-Sheet 4 for transmitting i a carburetor as of the cylindersi Patented May 3, 1949 FUEL s'urru FOR orrosnn onnmna enemas ar c. menu-rev, Cedarburg,-Wis.

' This invent-ion relates toengine fuel systems vaporized'jruel mixtures from in the case of two-cycle engine operation. I v I I The invention'has been applied to the construction of high-powerlight weight two-cycle I V Application March 9.194s,- Serial No. 653,399

' "'e'cmii i. 101423-56) ofli'lg. 3 midway between the center lines or the cylinders;

Fig. 'l is a-similar section taken on line 86 of Fig. 3, on the center line of the cylinder rarair-cooied engines having a weight-to-power ratio. of one pound per horsepower and having two cylinders firing substantially simultaneously with their cranks disposed closely adjacent on the crankshaft and in opposition to each other.

In such engines the fuel enters the crankcase from the carburetor, mixing chamber or'ieed line and is pre-compressed therein for force feed into the cylinders.

One of'the objects of the. present invention is of the crankcase into separate precompression chambers for the two cylinders and therebyretiming the amount of ofisetforthe cylinders.

Another object of the invention is to, provide a simplerlighter weight rotary valve constructionfor admitting the fuel to the crankcase.

I Another object is to provide a smaller cranke ,case with the volumetric capacity proportioned to thecylindersto obtain'a greater pre compression of the'fuel.

Another object is to provideaycrankcasei which in relation to the valveinlet' and transfer ports effects a more nearlyjequal delivery 'offue1 to the two cylinders.

' to reduce engine vibrations resulting from oirsetting of the cylinders, byavoiding theseparation of the housing. The

' body is open and cheek extending acrossthe thest from the intake; and

Fig. 8 is a, detail section showing the baflle in elevation and the far cylinder in section. The engine illustrated has a central two throw crankshaft I mounted for rotation in a housin 2' by means of a needle bearing 3 at the driving end of the shaft and a second needle bearing 4 at the opposite end of the shaft.

The housing 2 is constructed to provide a minimum volume necessary to enclose the cranks in their operation. For this purpose the housing hasone end reduced in diameter to receive the needle bearing 3. The other end of the housing has studs 5- on the outside for bolting a crankcase cover 6 thereto to seal the housing closed.

The housing 2 carries the engine cylinders I and 8 which are bolted thereto on opposite sides cylinders I and 8 have their axis substantially paralleland offset longitudinally of the crankshaft just sufilcient'to accommodate the two' corresponding crankthrows 9 and ill of shaft I in close juxtaposition.

. Thethrowslfl and, I0 have a common inner axis of shaft I.

Each throw 9 and 10 has an outer cheek l2 with a counterweight "l3 opposite the corresponding crank.

'Another' object is to; compensate for. any-differences in possible richness of the fuel delivered to the two cylinders. V Another objectisto providefor moreeffective lubricationof the cranks 'and bearings.

An embodiment of the; invention is illustrated in th e accompanying drawings inwhich:

' Figure 1 is a perspective viewer the engine with parts removed and sectioned;

. Fig.2 is an exploded perspectivefview of the crankshaft and rotary valve constructions; Fig. 3 is a section'through thecrankshaft housing and assembled taken on a plane axially of the shaft and at right'angles to the center lines 1 two cylinders I and-8.

} axial section through the housing *and assembled parts taken at right angles to,

Fig.3;

a transverse section through the hous-- eac line H of Fig. 3 on the center line oi thecyIinderneareStthe'intake; g 618a similar section, taken-callus The throws S and Hi have crankpinsj it upon which are mounted the connecting rods l5 having their outer e'nds pivoted to the wrist pins' IS inside the correspondingpistons I! for cylinders I and 8. 1 r

- The crankpins ,are disposed diametrically opposite each other on the crankshaft to provide "for substantially-simultaneous operation'of the The port 18 is preferably on'the side of the cover 6 nearest the near cylinder 1. The admission'condu'it 19 from a, carburetor, not shown,

I is also preferably disposed on the same side of the cover 6 as the port l8, but in the outer-wall of the cover insteadof the inner wall, and preferably above the port. A passage 20 through cover Gconnects conduit IS with port l8. The'shaft I carries a single circular valve disc 2| ,which presses against the inner wall of the cover 6 and is adapted, to alternately cover and port i Forthis purpose the disc 3 with and uncover the port It during a part of each revolution of the disc with shaft I.

The disc 2| is pressed against the cover 6 by a spring washer 23 disposed between the disc and the adjacent cheek l2. The disc 2! is driven by means of a pin 24 extending fromthe adjacent cheek l2, preferably in line with crank pin It, and into a recessin a boss 25 on the face of the disc.

The cylinders 1 and 8 have cylindrical liners 26 in which the pistons l1 reciprocate. A lateral offset 21 in housing 2 and in the outer wall of each cylinder provides a passage 28 for fuel to a transfer port 29 through the corresponding liner 26 and into the cylinder.

Each cylinder 1 and. 8 is provided with an exhaust port 30 through its wall opposite the transfer port 29.

The inlet ports 29 and exhaust ports 30 for each cylinder are adapted to be covered and uncovered by the'corresponding piston l1 as the latter reciprocates in the cylinder.

One of the problems in the construction of an engine of this type in which the fuel is fed into a singlechamber crankcase, is that of obtaining a satisfactory equal distribution of fuel to the cylinders. Where the fuel supply to one cylinder is more lean than to the other the lean cylinder is apt to overheat.

In carrying outthe present invention a more nearly equal distribution of fuel is obtained to the two cylinders by providing a bafiie 3| in the mouth of ofiset passage 28 of housing 2 for the far cylinder 8 to direct more fuel into the far cylinder, and by locating the transfer port 29 for far cylinder 8 at a slightly greater radial distance from the center line of shaft I than the transfer port 29 of the near cylinder 1 so that the intake port for cylinder 8 is opened first.

The baflie 3| has its tip extend downwardly adjacent the path of the corresponding crank and connecting rod so that fuel condensation on the baflie drips onto the crank for lubricating the latter. The path of the near crank is downwardly on the side of port l8 and upwardly toward baffle 3| so that it tends to throw fuel in the direction of the baflie for entrance into cylinder 8.

The location of port l8 circumferentially in the cover 6 is preferably on the lowerside of the near cylinder 1 so that the near crank tends to sweep the fuel toward cylinder 8 in the rotation of the shaft.

The differential radial distance of the transfer ports 29 may be obtained by machining the face of the. cylinder pad 32 on housing 2 for the near cylinder 1 to a distance from the aXis of shaft I about two one hundredths of an inch less than the corresponding distance for the cylinder pad 33 for cylinder 8. By reason of this differential between the cylinder pad locations, the cylinder 8 is located at a greater distance from the axis of shaft l than is cylinder 1, which fact effects an uncovering or opening of the transfer port 29 for cylinder 8 sooner than for cylinder 1.

It is preferable to employ both ways of inducing more fuel into the far cylinder 8, although it is possible to utilize either one of the ways alone in a given structure.

The invention provides for a minimum axial offset of the cranks and cylinders, thereby greatly reducing the torsional forces resulting from simultaneously firing of the cylinders, and making it possible to lighten the weight of the crankcase without danger of over stressing the same.

The feeding of fuel into the crank case from the end, and its equal distribution into the opposite cylinders is also importantin providing fol light weight construction of the engine.

An additional bearing 34, preferably a ball bearing, may be'disposed adjacent the outer cheek l2 of the crank throw for cylinder 8. Oil seals 35 and 36 should be provided at opposite ends of the crankcase. An additional oil seal, not shown. may be provided on the cam shaft for timer 31.

Various embodiments of the invention may be employed within the scope of the accompanying claims. I

I claim:

1. In an engine of the class described, a crankcase, a crankshaft operable therein, a pair of cylinders carried by said crankcase and differently spaced from said crankshaft in diametrically opposed relation with their center lines of!- set longitudinally of the crankshaft just sufilcient to accommodate the corresponding crankthrows side-by-side on the shaft, a single fuel inlet port for said crankcase disposed in one end thereof on the side of the near cylinder thereto, and a rotary fuel inlet valve operable by said crankshaft to govern said fuel inlet port and supply fuel to said crankcase.

2'. In an engine of the class described, a' crankcase, a crankshaft operable therein, a pair of cylinders carried by said crankcase and differently spaced from said crankshaft in diametrically opposed relation with their center lines offset longitudinally of the crankshaft to accommodate the corresponding crank throws side-by-side on the shaft, a single fuel inlet port for said crankcase disposed in one end thereof on the side of the near cylinder thereto, a fuel inlet valve operable by said crankshaft, to govern said fuel inlet port and supply fuel to said crankcase and means cooperating with the location of said inlet port to equalize the distribution of fuel from said inlet valve through the case to the cylinders.

3. In an engine of the class described, a crankcase, a crankshaft operable therein, a pair of cylinders carried by said crankcase in diametrically opposed relation with their center lines offset longitudinally of the crankshaft to accommodate the corresponding crank throws side-byside on the shaft, a fuel inlet valve at one end of the crankcase operable by said crankshaft, and a baffle in said crankcase disposed in the path of fuel moving therethrough from said inlet valve to equalize the distribution of fuel to the cylinders.

4. In an engine of the class described, a crankcase, a crankshaft operable therein, a pair of cylinders carried by said crankcase in diametrically opposed relation with their center lines offset longitudinally of the crankshaft to accommodate the corresponding crank throws'side-byside on the shaft, said cylinders having transfer ports communicating between the corresponding cylinders and the crankcase and adapted to be opened and closed by the pistons in the cylinders durin operation'of the engine, a fuel inlet valve atone end of the crankcase operable, by the crankshaft in synchronism with the .movement of said pistons, and means to effect .uncovering of the transfer port for the cylinder which tends to be most lean in fuel prior tothe uncovering of the transfer port for the other cylinder.

5. In an engine of the class described, a crankcase, a crankshaft operable therein, a pair of cylinders carried by said crankcase in diametrically opposed relation with their center lines offset longitudinally of the crankshaft to accommodate the corresponding crank throws side-by-side on the shaft, said cylinders having transfer ports communicating between the corresponding cylinders and the crankcase and adapted to be opened and closed by the pistons in the cylinders during operation of the engine, and a fuel inlet valve at one end of the crankcase, the transfer port for the cylinder which tends to be most lean being disposed at a greater distance from the center line of the crankshaft than the transfer port for the other cylinder to provide for earlier injection of fuel into the lean cylinder.

6. In an engine of the class described, a crankcase, a crankshaft operable therein, a pair of cylinders carried by said crankcase in diametrically opposed relation with their center lines offset longitudinally of the crankshaft to accommodate the corresponding crank throws side-by-side on the shaft, said cylinders having transfer ports communicating between the corresponding cylinders and the crankcase and adapted to be opened and closed by the pistons in the cylinders during operation of the engine, and a fuel inlet valve at one end of the crankcase, the cylinder pad of said crankcase for the cylinder tending to be most lean in fuel being disposed at a greater distance from the axis of the shaft than the cylinder pad for the other cylinder.

'7. In an engine of the class described, a crankcase, a crankshaft operable therein, a pair of cylinders carried by said crankcase in diametrically opposed relation with their center lines offset longitudinally of the crankshaft to accommodate the corresponding crank throws side-by-side on the shaft, a fuel inlet valve atone end of the crankcase operable by said crankshaft, and a baflle in said crankcase disposed in the path of fuel moving therethrough from said inlet valve to equalize the distribution of fuel to the cylinders, said baflle being disposed adjacent the path of movement of one of the cranks and above the same to increase lubrication of the crank by dripping of oil from the baffle onto the crank.

8. In an engine of the class described, a crankcase, a crankshaft operable therein, a pair of cylinders carried by said crankcase in diametrically opposed relation with their center lines offset longitudinally of the crankshaft to accommodate the corresponding crank throws side-byside on the shaft, said cylinders having transfer ports communicating between the corresponding during operation of the engine, a fuel inlet valve at one end of the crankcase operable by said crankshaft, and a baflle in said crankcase disposed in the path of fuel moving therethrough from said inlet valve to equalize the distribution of fuel to the cylinders, said baiiie being disposed near the entrance to the transfer port for the cylinder tending to be most lean in fuel and extending toward the corresponding crank throw to'direct more fuel into said cylinder. 9. In an engine of the class described, a crankcase, a crankshaft operable therein, a pair of cylinders carried by said crankcase in diametrically opposed relation with their center lines offset longitudinally of the crankshaft to accommodate the corresponding crank throws side-by-side on the shaft, said cylinders having transfer ports communicating between the corresponding cylinders and the crankcase and adapted to be opened and closed by the pistons-in the cylinders during operation of the engine, a fuel inlet valve at one end of the crankcase operable by said crankshaft,

and a baffle in said crankcase disposed in the path of fuel moving therethrough from said inlet valve to equalize the distribution of fuel to the cylinders, said baflle being disposed near the entrance to the transfer port for the cylinder tending to be most lean in fuel and extendin toward the corresponding crank throw to direct more fuel into said cylinder and extending close to the path of the crank to provide added lubrication for the crank by dripping of fuel from the baflie as the crank passes the same.

ELMER C. KIEKHAEFER.

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

UNITED STATES PATENTS

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