US2699764A

US2699764A - Air cooled internal-combustion engine

Info

Publication number: US2699764A
Application number: US271506A
Authority: US
Inventors: Elmer C Kiekhaefer
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-02-14
Filing date: 1952-02-14
Publication date: 1955-01-18
Anticipated expiration: 1972-01-18

Description

Jan. 18, 1955 E. c. KIEKHAEFER 2,699,764

AIR coousn INTERNAL-COMBUSTION ENGINE Filed Feb. 14, 1952 2 snets-sheet 1 lill/111111111111111 INV l I fr @jf-ahy@ Jan. 18, 1955 E. c. KIEKHAEFER AIR cooLED INTERNAL-COMBUSTION ENGINE 2 SheetS-Sheeb 2 Filed Feb. 14, 1 .952

United States Pate-nt-Oiice 2,699,764 `azextted Jan. 18,v 1955 LIlfCooLED mrERNL-COMBUS'TIN Elsa C Kia-haces Cedars-fe 1Wi ,s i @Applicaties Februar-y 14, 1952, 's4eria1 run-271,506

, .s claims.. (on. 12s-141.6)

invention relates .to p .internal-combustionengines .andparticularly. to.air-.coolingzsystems therefor. a A.

.charging. as the cylinder is exhausted.-l L.. The .spark plug -12 of each cylinder 4 and 5. is-energizedby .the magneto. unit 13` whichis supported by .thecircular liange .14 at the forward end-oi the engine. Thetwocycle.operation of the engine allows the-magneto .1o. be directly. mounted on the crankshaft 3 for operation.

vairfreinet-heA correspondinglcranklchamber 8 through the passage 11 into the cylinder for scavenging-and; r'e- The rotor 1S and cam 16 of the magneto areffixedon `the .shaft 17 .or..overhanging end VjournalY of` crankshaft .3 which is supported in the bearing 18 adjacent-'tothe .rotor and-cam. The-stators 19 are mounted onthe-plate I .1`he, invention` providesan impeller of. centrifugal operationhaving a'nurnber ofaxial dischargeswhereby `the 'air.may .be more easily directed as.requ1red.to.the`yliriders of/the engine,. and Aparticularlythe. moreremote of. two or more .cylinders arranged in-.lineand both .sides thereof...A An object. of the. invention is.to provide for.v delivery `Aof equal .amounts of..air toeach .ofthe .cylinderso an infline engine at all. speeds, .particularly lat idlingas wellas at high speed .and to. both sides-of .the enginein the required amounts..

A .further .object is toA .reduce .-.snbstantially .the vanes and ducts normally required; to leect equalcooling of `the several. cylinders..

AnotherY object is toprovide'icontrol of .the-axiaLair discharge of the irnpeller..tovreach4 the remotelcylinders of the engine. Anotherobject is to provide-forthe easieranaintenance 4v01? the. impeller .and .easier access to .theimpeller blades -andxthe casing.

.A further object is 4tohprmoyicle an:irripell-er..casing` isselfcleaning and more .readily suited..fo r. usefin .chain .saW enginesandthe like.. ,g

.Anotherobject is to mount the im'peller` on-the engine .shaftandxoventhe magneto Aand provide` .forl delivery lof air to the engine cylindersfor coolingy withsubstantial These .and other objects.andadvantageswillbe Amore fully set. forth. in the followingdescription of sa. preferred embodiment of .the invention as..illustrated:.in theiacom -panying drawing.` L.In ,the drawing:.

Fig 1 is a top. plan `v'ew.ofithe.engineA with-.parts .thereof broken away and sectionedzto. showthe 'magneto andfdetails of construction .of.the.impellerlcasing-and scroll;

Fig. .2 ishaside elevation.ofdthe-.enginewith theA ini- --pleller casing removedand. with` .the scroll .broken away and sectioned to show the scroll congurationlin relation Eig. 3 is .atransverse .section through. the-.engine look- Aing toward thefscroll ,member andwith .tially broken away andsectionedpandtjf thelatter par Fig, 4"is a front elevationof. the..engineandi-impeller casing with apart `of .the latter-broken.`away''toA show the impellerandscroll member.

1 The engine 1 shownin the vdrawings the.

`ca`se 2whichcarries the. horizontalcrankshaft The Otwo.Cylinders 4 and 5 are arranged infline andextend `horizontallyon onesideof the;engine.

by the piston' to allow. transfer of` the compressed fuel .timing .ofthe ignition -the .reciprocation lof the-pistons.

Led on. .shaft 17 of the crankshaft .number to allow arelatively-free air A20. which. latterl carries the-timing -meansf 21- operated ...by.. the cam 16p. Plate 20 `is--mounted on Harige-14 -for rotational adjustment on the crankshaft axis wherebythe may be adjusted inrelation-.t0

The external'danges 22 of cylinders `land 5' provide ..the..heat dissipation necessary for cooling of the-,cylinders 20} `.The vflanges `are-formed integrally with the outer-cast by. passingair over the cylinders and between the-flanges.

portion of cylinders '4 and-5 andextend radiallythereof.

.The anges. are arranged in a series extending the-length ofthe cylinders. over passages 11 `formed therein `and .surroundports-S thereof.

The .air is supplied by the-impeller 23 whichismount- 3 to rot-ate therewith.

lnipelleixt?) includes `thebushing -24 .which-is-mounted -directly on the tapered portion 25- of Vshaft 17' and extends` over .the reduced and threaded. end-260i -the shaft;

AThe hubportion 2.7 of the impeller mounted on bushing .24. andthe .s kirt A2S .are annularly formedl andi-extend .oyen-.the magnetol. y.peller are formed integrally with hub 27-and`skirt`-28 .and extend to the edge ofthe skirt. VThe forward-inner .ends of `the vanes' 'are radially spaced-from the. a-xis lof The-radial vanesV 29 of theimj-rotation. of the impeller.H The `nut 30 which is turnedwin lone'direction on the threaded-end 26 of shaft- -17- secures thenimpeller on bushing 24- and the bushing on Vthe -tapered portion- 2 5 of shaft 17.

If. desired, nutl30=may be-iitted within bushing-24 to engage and withdrawthe s'arne `for-removal ofthe irnpellerA from. the. shaft by turning nut-Silin the lopposite direction.

, According `to Vthe. inventiong-the outer edge of each vane isgenerally arcuate -to fit within the hemispherical casing 31 .supportedby the scroll plate: 32;- Plate 32 --comprises preferably a single-cast-memberforminga part .of crankcase.

2 and-supporting the bearingl-jfor shaft 17. The outerrdimension of plate 32 is generally circular and includes a projecting- Wall 33 which-extends alongside and .to the end 'of the thereto; The annularange 34 .forwardly of. theengine and is provided with a"- marginal -recess 354 in the .front outer edge circumferential. offset margin 36 -cylinder- A, adjacent of plate 32 `projects -thereoi to -rec'eive .the Vor" casing 3-1 with ja tight t and to support-the casing. The several #spaced .lugs.3.'7 .extending from the plate into thecasing-are drilled and tapped to receive the screws 38 for securing -the casing thereto.

Casing 31 as provided is, readily removable by removingrscrews 38 andhas a-spherical interior surfacewhich isyunobstructed for `wiping clean at frequent-intervals 'as required. in .certaintypes of service -and-for operation of the impeller with maximum eiiiciency and' a minimum pressure loss due to friction. p

The hernispherical-casing .31 is readily "adaptedto be ``variously formed, e.. g. stamped,- spun,V or die-cast. 1 The :cas1ng31Lshown1n the drawings-is spun-as a bowl w1th the offset margint36 whichiits the-marginal recess35f-of plate 32. asA described. The central air :inlet-of*` the-casing comprises a plurality of-holes 39-Which are-oa sizeand intake: While excluding foreign matter such as wood chips, leaves and thelike. If desired a screen of any suitable meshV mayalso. be 4mounted over the air; inlet 0r substituted 'for the series of ..1 The .interior-spherical dimension "oficasing L31 islarger .thantheoutlines of vanas-29 allowingthroughout-amini- `mum .clearance therebetween suiicient -for relative -free movement. The. casing .is .dismounted from--plate--S-ZI-by removing screws 38 which with removal of the casing allows access to impeller 23 and the interior and

outlets

40 and 41 of plate 32. The removal of impeller 23 thereafter provides unrestricted access to and from all sides of magneto unit 13.

-low the air to pass therethrough in a direction beneath `cylinders 4 and 5 and between cover 43 and the cylinders.

Y According to the invention the air is driven by centrifugal force axially into the scroll 45 formed in plate 32 and continues to move rotationally therein until reaching

openings

40 or 41. Scroll 45 is of axial development and extends in a circle about the axis of rotation of the impeller and terminates at opening 40. A part of the air delivered by impeller 23 passes through opening 40 from scroll 45 or is deflected through opening 40 by the cut-off member 46 formed integrally with plate 32. Member 46 is angularly disposed and extends from opening 40 along the back side of wall 33 and adjacent to cylinder 4. The air passing through opening 40 into hood 42 blankets cylinders 4 and 5 with cooling air which passes over flanges 14 thereof towards the rear of the engine. The cut-off member 47 is integrally formed with plate 32 and is angularly disposed to deflect air through opening 41. Member 47 projects within plate 32 towards the impeller into the rotationally moving air stream and delivery of the air necessary to cool the underside of the cylinder. The air from opening 41 passes between cylinders 4 and 5 and cover 43 towards the rear of the engine or through the openings in the cover provided for pipes 44. The separate streams of air passingV over the cylinders from

openings

40 and 41 cool the corresponding parts of the cylinders which include4 the transfer passages 11 and exhaust openings 9. The relative sizes and locations of

openings

40 and 41 and

members

46 and 47 provide a division of the cooling air delivered and provide the desired relative cooling of the exhaust-and-transfer-port sides of the cylinders. The air from both sides of the cylinders vpasses from between hood 42 and cover 43 at the rear of the engine.

In the embodiment shown, the proportion of air cooling the transfer port side of cylinders 4 and 5 increases with the speed of the engine and total air-delivery of impeller 23 to coincide with the general cooling requirements of the type of two-cycle engine shown and described.

Conditions of service such as in chain saw units, or where excessive dust and dirt are prevalent, create problems of frequent cleaning of the impeller and casing. The ease of removal of casing 31 which provides access to impeller 23 and the ease of cleaning the bowl-shaped casing particularly affords some assurance of the proper maintenance and cleaning necessary.

The impeller operates within casing 31 with a minimum of frictional losses which allows the magneto to be advantageously mounted on the crankshaft between the impeller and the engine without disadvantage. The air from the impeller and casing is discharged axially into scroll 44. The scroll is developed axially to outlet 40 from which the air is released. Without guide vanes, the air passes over cylinders 4 and 5 in substantially equal amounts.

The hemispherical casing is virtually self-cleaning by reason of the smooth inner contour and the axial discharge of the casing into the scroll plate. The discharge of air from the entire perimeter of the casing is allowed without Vobstruction with the exception only of the small lugs 37 which support the casing.

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

c aim:

l. In an internal combustion engine of the class dey having a hub and extending skirt, a series of blades extending radially from said hub and axially along said skirt, a hemispherical casing for said impeller, said blades having an outer dimension providing a minimum operating clearance with the interior of said casing and providing for the axial discharge of air from between said skirt and said casing, a scroll plate secured to and closing said casing at the periphery thereof and having a discharge opening adjacent to one of said cylinders, and a cut-off member extending along one side of said opening to direct the air to the side of said last named cylinder immediate thereto, the scroll of said member extending circularly to the adjacent side of said discharge opening and of axial development to receive the air from said casing and discharge the air through said opening in a direction toward the other side of said cylinder.

2. In an engine of the class described, a series of cylinders arranged in-line and having external fins for aircooling, said cylinders having parts with dissimilar cooling requirements on corresponding sides, an impeller mounted on the projecting forward end of the engine crankshaft to rotate therewith and having a hub and extending skirt, a series of blades extending radially from said hub and axially along said skirt rearwardly toward said cylinders, a hemispherical casing for said impeller, said blades having an outer dimension providing a minimum operating clearance with the interior of said casing and for the axial discharge of air from between said skirt and said casing, a scroll plate secured to said engine to support said casing at the periphery thereof and having separate discharge openings adjacent to the forwardmost cylinder, and cut-off members carried by said plate at each opening thereof to direct given proportions of air to said parts of said forwardmost cylinder, said member including a scroll of axial development to receive the air from said casing and extending to one of said discharge openings to discharge the air through said opening in a direction rearwardly toward the rearwardly disposed of said cylinders.

3. In an engine of the class described, having a crankshaft and a magneto operatively mounted on said crankshaft forwardly of the engine, a series yofcylinders arranged in-line and having external tins for air-cooling, an impeller mounted on said engine crankshaft to rotate therewith and having a hub and a skirt extending over said magneto, a series of blades extending radially from said hub and axially along said skirt rearwardly toward said cylinders, a hemispherical casing for said impeller, said blades having an outer dimension providing a minimum operating clearance with the interior of said casing and providing for the axial discharge of air from between said skirt and said casing, ascroll plate secured to said engine and between the latter and said 'magneto to support said casing at the periphery thereof, said plate having a dischargeopening adjacent to the forwardmost cylinder and a cut-off member extending along one side of said casing at said opening to direct the air to the adjacent parts of said forwardmost cylinder, said plate having a scroll of axial development to receive the air from said casing and extending to said discharge opening to discharge the air through said opening in a direction rearwardly toward the rearwardly disposed of said cylinders.

4. In'an engine of the class described, a series of cylinders arranged in-line and having external tins for aircooling, an impeller mounted at the forward end of the engine crankshaft to rotate therewith and having a hub and a rearwardly extending skirt, a series of blades extending radially from said hub and axially along said skirt toward said cylinders, a hemispherical casing for said impeller and having a central screened inlet opening, said blades having an outer dimension providing a minimum operating clearance with the interior of said casing and disposed for the axial discharge of air from said casing, and a scroll member having a discharge opening adjacent to the cylinder immediate thereto and secured to said engine, said member having an annular flange Vfitting within the periphery of said casing toV support the latter and allowing removal thereof for cleaning and access to said impeller.

5. In an engine of the class described, a series of cylinders arranged in-line and having external fins for aircooling, an impeller mounted on the projecting forward end of the engine crankshaft to rotate therewith and having a hub and extending skirt, a series of blades extending radially from said hub and axially along said skirt rearwardly toward said cylinders, a hemispherical casing for said impeller and having a central screened inlet opening, said blades having an outer dimension providing a minimum operating clearance with the interior of said easing and for the axial discharge of air from between said skirt and said casing, a scroll plate secured to said engine supporting said casing at the periphery thereof and having a discharge opening adjacent to the forwardmost cylinder, and a cut-olf member extending along one side of said plate at the opening thereof to direct the air to the adjacent parts of said forwardmost cylinder, said plate including a scroll of axial development to receive the air from said casing and extending to said discharge opening to discharge the air through said opening in a direction rearwardly toward the rearwardly disposed said cylinders, said casing being adapted to be removed from said member for cleaning and access to said impeller.

6. In an engine of the class described, a series of cylinders arranged in-line and having external fins for aircooling, said cylinders having parts with dissimilar cooling requirements on corresponding sides, an impeller mounted on the projecting forward end of the engine crankshaft to rotate therewith, a casing for said impeller, a scroll plate secured to said engine to support said casing at the periphery thereof and having separate discharge openings adjacent to the forwardmost cylinder, cut-of`f members carried by said plate at each opening thereof to direct given proportions of air to said parts of said forwardmost cylinder, and cover members extending over said cylinders and enclosing said openings to receive the air from said casing and direct the air over said corresponding parts of said cylinders in a direction rearwardly of said engine.

7. In an engine of the class described, a series of cylinders arranged in-line and having external ns for aircooling, said cylinders having parts with dissimilar cooling requirements on corresponding sides, an impeller mounted on the projecting forward end of the engine crankshaft to rotate therewith, a casing for said impeller, a scroll plate secured to said engine to support said casing at the periphery thereof and having separate discharge openings adjacent to the forwardmost cylinder, cutoff members carried by said plate at each opening thereof to direct given proportions of air to said parts of said forwardmost cylinder, and cover members extending over said cylinders and enclosing said openings to receive the air from said casing and conduct the air over said corresponding parts of said cylinders rearwardly of said engine, said plate including a scroll of axial development to receive the air axially from said casing and extending to the side of one of said discharge openings to discharge the air through said opening in a direction toward the rearwardmost cylinder.

8. In an engine of the class described, a series of cylinders arranged in-line and having external fins for air-cooling, said cylinders having parts vwith dissimilar cooling requirements on corresponding sides, an impeller mounted on the projecting forward end of the engine crankshaft to rotate therewith, a casing for said impeller, a scroll plate secured to said engine to support said casing at the perpihery thereof and having separate discharge openings adjacent to the forwardmost cylinder, and cutoff members carried by said plate at each opening thereof to direct given proportions of air to said parts of said forwardmost cylinder, said member including a scroll of axial development to receive the air from said casing and extending to one of said discharge openings to discharge the air through said opening in a direction rearwardly toward the rearwardly disposed of said cylinders.

References Cited in the file of this patent UNITED STATES PATENTS Re. 23,146 Packwood Sept. 13, 1949 2,233,825 Walsh et al Mar. 4, 1941 2,236,706 Damonte Apr. 1, 1941 2,245,989 Leathers June 17, 1941 2,326,335 Dehn Aug. 10, 1943 FOREIGN PATENTS 578,131 Germany June 10, 1933 667,397 Germany Nov. 10, 1938 360,103 Italy June 11, 1938 505,078 Great Britain May 2, 1939