US2216342A - Internal combustion engine - Google Patents

Description

Oct. 11 1940. E. s. HALL INTERNAL COMBSTION ENGINE Filed Maron 27'l 19:59

3 Sheets-Sheet l INVENTOR @MSM ` ct.- l, W40.

E. S. HALL INTERNAL COMBUSTI ON ENGINE :s sheets-sheet 2 'Filed March 27, 1939 R O T. N 4 E V m MSM rOct. 1,1940. I E. s; HALL INTERNAL COMBUSTION ENGINE Filed March 27, 1959 3 Sheets-Sheet 3 INVENTOR atented Oct. l, 1940 UNITED STATES PATENT i'oFI-lcE 17 claims,

This invention relates to internal combustion engines and its salient object is to provide a most compact engine of minimum bulk and weight. Compactness and minimum weight are best attained with those engine types which have small crankcase volume, as for example, the radial erigines in which the cylinders face each other around a common mechanism, or the opposed cylinder -engines or the barrel type engines in which similar groups of cylinders face each other with the engine mechanism between them. This invention may be conveniently described as applied to the normal barrel engine with cylinders parallel to the shaft in twoi-similar groups facing each other with the rotary-reciprocating mechanlsm between them, but it is applicable also to other types of engines such as those mentioned above.

An object of this inventionis to provide a shcrter and more compact parallel cylinder engine of less specic weight. and to provide -means for reducing the length and weight oi. 4such an engine by about 25% under what has been possible.

25 In a parallel'cylinder engine of the normal type, bearing loads are much lowerand other mechanical conditions much ,superior if the engine is run on the two-stroke cycle. For twostroke operation, uniflow scaverige is preferred, with intake ports at one en'd of the cylinder and exhaust ports at the other end. Thermal conditions in thepistons are best if the pistons control the intake ports while the exhaust ports arelcon-V trolled by valves. An object of this invention is to provide a uniflow two-stroke engine with irnproved sleeve valves and sleeve valve operating means, at thesame time using the sleeve valves to permit shorter piston members than would otherwise be possible for a given piston stroke, thereby shortening the engine and reducing its weight. Another object is to reduce engine weight and size still more by using the sleeve valves as cylinder liners, dispensing with the" need of ilxed liners and separate valve systems. Another object is to provide the piston members with oil contrpl rings which never pass over the piston-controlled ports, and at the same time having shorter piston members than would be possible, even without oil control rings, if sleeve valves were not used. The foregoing objects are attained by using single sleeve valves in a' twostroke parallel'cylinder engine, the sleeves having strokes longer than usual and timed almost in time with the-piston strokes, softhat the'sleeves,fl

55 as they move outward from the cylinders, retain the piston rings in operable position after the rings have passed beyond the mouths of the cylinders themselves, thereby permitting the piston members to be much shorter, 'resulting in a shorter and lighter engine. the reduction amounting ordinarily to about 25%.

Another object is to provide sleeve valves for a parallel cylinder engine with driving means operably connecting the sleeves with the rotary-reciprocating engine mechanism, whereby the l0 sleeve valves are given strokes somewhat shorter and preferably slightly advanced in timing relative to the strokes of the pistons.

Another :object is to provide sleevevalves which extendv thru both coaxial cylinders in a normal parallel cylinder engine, the sleeves serving not only as valves and liners for the cylinders, but as crosshead guides for the piston members. A further object is to provide mechanisms for driving such combined sleeve valve and crosshead guide units.

Another object is4 to provide individual sleeve valves for the several cylinders of a parallel cylinder engine, so that the port timing can be suited to each cylinder, with means for driving the sleeves from the engine shaft independently of the rotary-reciprocating engine mechanism. Another ob ject is to provide a cam mechanism for driving such individualsleeve valves so as to make possible giving each sleeve the optimum movement relative to piston movement, for the best conditions of port timing andwear. Another object is to provide improved cam driving mechanisms -for sleeve valves.

In parallel cylinder engines of the wabbler type, where the rotary-reciprocating mechanism comprises a wabbler mounted on bearings in-V clined to the shaft. some means oi' restraining the rotation of the wabbler or of controlling its float is desirable. An object of this invention is 40 to provide means for driving sleeve valves directly from the wabbler which driving means will function also to control the wabbler float, preferably permitting the wabbler toA have its true geometric motion. Another object is to provide means for eliminating excessive clearances in sleeve valve .operating mechanisms in a parallel cylinder engine.

In any. two-stroke engine. for best economy, fuel injection should be used. An object of this invention is-@to provide an improved fuel injectionv system especially suited to a parallel cylinder engine.

'I'hese and other objects of the invention and 1 the means of attaining them will be more clear from the following description in connection with the drawings in which g Fig. 1 is a longitudinal section of a parallel cylinder engine having a-wabbler mechanism and individual single sleeve valves, one in each cylinder, the valves being driven by cam mechanisms independent of the wabbler mechanism;

Fig. 2 is a radial or plan view, in section, of a reciprocating member of the mechanism shown in Fig. 1;

Fig. 3 is a partial transverse section of the wabbler mechanism of Fig. 1 taken thru the midsection of the reciprocating member of Fig. 2;

Fig. 4 is a longitudinal section of another parallel cylinder engine having a wabbler mechanism and tubular members each serving as sleeve valves for the cylinders of each pair and as a crosshead guide for the reciprocating piston member, these tubular members being driven directly from the wabbler, and the driving mechanism serving also to control the wabbler float and maintain the geometrically correct movement of the wabbler;

Fig. 5 is a radial or plan view, in section, of one of the tubular members of Fig. 4, with the crosshead portion of the reciprocating member in in place A,

Fig. 6 is a transverse section thru the mechanism of Fig. 4, showing portions of the driving arrangements of the tubular members;

Fig. 7 is an alternate construction of the mechanism for driving the tubular valve and crosshead guide members directly fromthe wabbler while maintaining the wabbler oat;

Fig. 8 is a longitudinal section of a parallel cylinder-engine of. thcam type, having a cam and roller rotary-reciprocating mechanism and sleeve valves, the latter being also crosshead f guides for the piston members and cylinder liners,

driven by another cam mechanism; and Fig. 9 is a partial transverse section taken on the line 9-9 of Fig. 8.

Referring tongs. 1 3 of the draw1ngsshaft` is mounted in bearings and I2 in cylinder blocks I3 and cylinderv covers I4 respectively. Casing member I is interposed between and bolted to cylinder blocks I3. Formed in cylinder blocks I3 are cylinders I6 with their axes parallel to shaft I0. Shaft I0 ls axially located by slipper thrust bearing 20. Swashplate 2| is fixed on shaft I0 in any suitable manner as by the splines and conical wedge pieces shown.

Wabbler 24, comprising two similar members bolted together.. is operably mounted with suitable bearings on `swashplate 2|. The two parts of wabbler 24 are solids of revolution, their peripheral surfaces 26 and 26 being cylindrical and the intervening surfaces 21 being plane.

Wabbler arm assemblies are spaced about wabbler 24, each assembly comprising a pedestal member 29, cap 29, wristpin bushing 39, and Capscrews 3|, together with wristpin 32 locked in radial 33 by set screws 34. Pedestal 23 has inner surfaces cylindrical and plane conforming respectively to cylindrical surfaces 25 and 26 and plane surfaces 21 of wabbler'A 24, and, as shown in Fig. 1, are bifurcated to straddle the inner portions of the two members of wabbler 24 to assist in holding them together and for additional strength of the arm and its attachment to the wabbler. Capscrews 3| clamp Wristpin bushing 30 between cap 29 and pedestal member 28, holding them vsecurely to wabbler 24. Bushing 30 is, free to rock and reciprocate on wristpin 32 as required by the operation of the mechanism, its axial movementibeing finally y checked by the cushion action of loose tting dashpots 35 formed in radial 33.

Radial 33 is operable in bore 36 in crosshead 31. Crosshead 31 vis operable in cylindrical bore I8 formed in casing member I5 coaxial with cylblocks I3 and are clamped to roller carriers |92 by screws |93. Rollers |95, integral with their pins, are operably mounted in half-journal bearings formed in roller carriers |92 and operably engage cam |94 which is xed on shaft I0.

Sleeve valves I9 are provided with intake ports 22 opening from the air chambers I3| in cylinder blocks I3 which are fed from suitable blowers or other means. Ports 22 are overrun and controlled by pistons l1. The head ends of sleeve valves I9 are bevelled internally to weaken them sufliciently so that they will expand under cylinder pressure toseal against leakage from combustion chambers |6| into exhaust ports 23.

Cylinders I6 in cylinder blocks I3 are closed by individual cylinder heads which form, with the heads of pistons |1, combustion chambers I6I. Fuel pumps |62 are arranged radially relative lto shaft I0 and aire operated by cam v|64 which is xed on shaft I0. Each fuel pump |62 is inserted in' a bore in cylinder cover I4- and extends outward toward one of the cylinder heads |60. Fuel nozzle |66 passes thru the body of fuel pump |62 and into cylinder head |60 with suitable packing nuts so that fuel may be delivered directly from fuel pump |62 to nozzle |66 under high pressure without any piping.

Operation of the engine on the two-stroke compression ignition cycle is well understood. Fuel injected thru nozzle |66 into the charge of air in combustion chamber |6| which charge has been heated by compression, ignites and the combustion drives the piston outward. Sleeve valves I9 are timed to open exhaust ports 23 well in advance of the opening of intake ports fore pistons I1 close intake ports 22, to permit supercharging the cylinders to blower pressure. Reciprocation of the piston members is accompanied by rotation of shaft I0 by the action of the .wabbler mechanism in a well-known manner. The construction of wabbler 24 and associated parts is such that practically no .torque reaction can be imposed on the wabbler, the wabbler normally tending to float in the middle of its rotational freedom. Should wabbler 24 tend to go to the limit of its rotational freedom, dashpots 36 may serve as cushions of oil and air to prevent knocking. Rotation of shaft I0 also causes rotation of cams |94 which coact with vrollers |95 and associated parts to drive sleeve valves I9. At the right of Fig. 1, both intake operating mechanism comprising slippers 54|' mounted in recesses 540 in Wabbler 54 andv in control ring being retained altho drawnseveral inches beyond and out of the mouth of cylinder I6. At the right of Fig. 1, it may be noted that this oil control ring never passes above ports 22.

Referring to Figs. 4-7 shaft 46 is mounted in bearings-4| and 42 in cylinder blocks 43 and covers 44 respectively. Casing member 45 is interposed `between and bolted to -cylinder blocks 43. Formed in cylinder blocks 43 are cylinders .46 with their axes parallel to shaft -4||.

vfrom and are spaced about Wabbler 54, each assembly comprising a pedestal member 5B, cap 59, wristpin bushing 69, and capscrews 6|, to-

gether with wristpln 62 carried by and locked` in radial 63. Pedestal member 56 has inner surfaces cylindrical and plane conforming respectively to cylindrical surfaces 55 and 56 and'plane surfaces 51 of Wabbler 54, and as shown in Fig. 4, are bifurcated to straddle the inner portions of the two members of Wabbler 54 to assist in holding them together, and for additional strength in the attachment of the Wabbler arm to wabbler 54. Capscrews 6| clamp wristpin bushing 60 between cap 59 and pedestal member 58, holding them securely to Wabbler 54. Bushing 6|)` crosshead 61. Pistons 4'| are vclamped to crosshead 61 by clamps 66 and screws 69.

For each reciprocating member comprising two pistons 41 clamped to a crosshead 61, an integral tubular member 49 forms a sleeve valve and cyli inder liner for each 4piston'41 and a crosshead guide for crosshead 51, the tubular member l49 being operable-in both opposite cylinders 46 of cylinder blocksv 43. and extending from one to the other within casing 45. Tubular members 49 are driven directly from Wabbler 54 by means of an cups in plungers 542 which plungers 542 are adjustable within bores in plungers 543, these latter plungers 543 being reciprocable in bores in cylinder blocks 43 andhaving arms 449| operably engaging tubular'members 49. to drive the same. Operating clearancesin the operating mechanism connecting Wabbler 54 with tubular members 49 are kept at a minimum by means of springs 544 and ball check valves 545 cooperating with-oil pressure vfrom the engine lubrication system supplied thru suitable conduits 546 from main bearings 4|.

- In Fig. 7 an alternate design of the sleeve valve operating mechanismtis shown. Plungers 543 with arms 49| are the same as those shown in Fig. 4, but inner plungers 642 are provided with offset terminal discs 649 operably engaging4 sock- Vets 540 in Wabbler 54. During operation of the mechanism, plungers 642 and terminal discs 640 rotate at the same speed asshaft 49.

Operation of the engine of Figs. 4-7 is similar to that of Figs. L-3. Tubularmembers 49 serve as sleeve valves, ascylinder liners, and as crosshead guides for the piston members. With their operating mechanisms in .the intercylinder lead that of the piston members by twenty degrees of shaft rotation, and since the axes of 4plungers 542 and 543 are on a circle of substantially half` the radius of the cylinder pitch circle, the length of stroke of tubular members 49 is substantially half that of the piston members. Whenever the driving load is momentarily off from one of the driving mechanisms comprising a slipper 54|, plunger 542 and plunger 543 and associated parts, spring 544 ac ts to elongate'tbe vplunger' member 'taking up any clearance, oil

entering thru check valve 545 to .substantially maintain the new length of the plunger member under load, any excessive stress which might result being vrelieved by -slight leakage of oil trapped between plungers 542 and 543.

' Slippers 54| or offset terminal discs 540 could operate directly on the plane outer faces of wabdispensing with the necessity for dashpot cushions 35 shown in Figs. 1-3. Slippers 54|, as they work around in recesses 549, may rotate more or less in their cups in plungers 542; terminal discs 640 and their plungers 642 Vmust rotate in plungers 543 as the Wabbler operates. If the Wabbler mechanism, were of any other type than that shown, control means of this sort might be 'inadequate because the enginei torque reaction would 'be upon them, but with the mechanism shown, the Wabbler control system must control only incidental tendencies of the Wabbler to de part from its true motion, caused for the most part by friction in the Wabbler bearings.

:isl

Referring to Figs. 8 and 9, shaft Bil-is mounted in bearings 8| and 62 in cylinder blocks 63. Casing. member is interposed between and bolted to cylinder 4blocks 53. Formed in cylinder blocks 83 are cylinders 8 6 with their axes parallel 15o-shaft 89; cylinders 84 formed in casing member 85 are coaxial with cylinders 86 and of somewhat larger bore.

Tubular member 99 is operable withinv cylinders 64 and 86 as movable cylinder liners, crosshead guide; and sleeve valves for the piston rmember comprising a pair of pistons 93 and connecting bridge portion. Cam member 81 is fixed on shaft 8|)` in any suitable manner and has a pair of cams 88 and another pair of cams |l9., Cams 66 engage rollers 90 integral with their pins to prevent rotation of the piston and sleeve valve members. A

Rollers 90 have their axes inclined for the double purpose of permitting the rollers to reach inward to a cam of smaller diameter, thus permitting a thicker and more rigid bridge portion for the piston members and tubular members' 99, and of introducing an outward radial component into the side thrust on the .piston members to avoid beam loading thereon, the resultant piston side thrust being towardample bearing area of the bridge portion of the piston member and of the tubular member Where the latter bears in cylinder 84 in casing member 95. The central or bridge portions of tubular members 99 are somewhat thicker than their sleeve valve portions. their exteriors conforming to the respective bores of cylinders 8f3 and 86. Moreover, the central or bridge portions of tubular members 99 are cam ground externally, with inward reaching portions to provide mountings for the rollers 91.

Operation of an engine with the mechanism shown in Figs. 8 and 9 is similar to that of the engine of Figs. 1-3. Piston thrust is converted into shaft rotation by the cam and roller mechanism instead of by a wabbler mechanism, and similarly, tubular members 99 are driven by cam and roller mechanism comprising cams 89 and rollers 9i.

An engine with the cam and roller mechanism is normally somewhat shorter and of less weight than an engine with the wabbler mechanism, but the reduction in engine length and weight resulting from the adoption of sleeve valves having unusually long strokes timed substantially with the piston strokes, is proportionally about the same. In a specific design, the length of the engine was reduced from 66" to 48", about 27%, and the reduction lin weight resulting from this reduction in length together with the use of the sleeve valves as cylinder liners and the elimination of any puppet or rotary valvev mechanism, was estimated at approximately 33%. These reductions assist materially in the attainment of two-stroke aircraft Diesel engines of less specic weight than that of present gasoline aircraft engines.

Having thus described the invention, it is obvious that the objects thereof as set forth herein have all been attained. While specific embodiments of the invention have been shown and described, it is understood that changes may be made in the arrangement and in the construction of the various parts without departing from the spirit or scope of the invention as expressed in the following claims.

I claim:

1. In an engine comprising a shaft, cylinders spaced about and parallel thereto, pistons and piston sealing means operable therewith,.and means operably connecting said pistons with said shaft: means for retaining said sealing means in operable position when withdrawn beyond the mouths of said cylinders and permitting said pistons (and therefore said engine) to be shorter and of less weight thanwould otherwise be possible, said means comprising sleeve valve members serving as cylinder liners and surroundingl .said pistons and sealing means, and reciprocable with telescopic effect on strokes shorter than, but

as frequent as and timed substantially with theV strokes of said pistons.

2. An engine comprising a shaft, cylinders spaced about and parallel thereto, sleeve valve members operable in said cylinders, pistons and piston rings operable within said sleeve valve members, mechanism operably connecting saidI pistons with said shaft whereby Athe strokes of said pistons accompany rotation of' said shaft, and means for reciprocating said sleeve valve members with strokes shorter than, but as frequent as and timed substantially with the strokes of said pistons retaining said piston rings in operable position within said sleeve valve members, even when said rings are withdrawn beyond the mouths of said cylinders, permitting said pistons (and therefore said engine) to be shorter and of less weight than would otherwise be possible.

3. A uniiiow two-stroke internal combustion engine comprising a shaft, cylinders spaced about and parallel thereto, cylinder heads closing the outer ends of said cylinders, sleeve valve'` members operable in said cylinders, pistons operable within said sleeve valve members, mechanism operably connecting said pistons with said shaft, intake ports in said sleeve valve members and controlled by said pistons, exhaust passages adjacent said cylinder heads and controlled by said sleeve valve members, and means for reciprocating said sleeve valve members on strokes shorter than, but as frequent as and timed substantially with the strokes of said pistons.

4. An engine comprising a shaft, cylinders spaced about and parallel thereto, sleeve valve members operable in said cylinders, pistons operable within said sleeve valve members, and a mechanism for the interconversion of reciprocation and rotation operably connecting both said pistons and said sleeve valve members with said shaft, the strokes of said sleeve valve members being shorter than, but as frequent as and timed substantially with the strokes of said pistons.

5. An engine comprising a shaft, cylinders spaced about and parallel thereto, sleeve valve members operable in said cylinders, pistonsoperable within said sleeve valve members, a Wabbler mechanism operably connecting said pistons with said shaft, and means operably connecting said wabbler mechanism with said sleeve valve' members for driving them with strokes shorter than, but as frequent as and timed slightly in advance of the strokes of their respective pistons.

6. An engine comprising a shaft, cylinders spaced about and parallel thereto, an individual sleeve valve member operable in each of said cylinders, pistons reciprocable within said sleeve valve members, mechanism operably connecting said pistons with said shaft, and means independent of said mechanism and operably connecting said sleeve valve members with said shaft for reciprocating said sleeve valve. members with strokes shorter than, but as frequent as and timed substantilly with the strokes of their respective pistons.

7. In an engine comprising a shaft and cylinders spaced about and parallel thereto, the combination of an individual sleeve valve member operable in each of said cylinders, pistons reciprocable within said sleeve valve members, a wab-' bler operably connecting said pistons with said shaft, and means for driving said sleeve valve inders facing each other: integral tubular members each serving as movable cylinder liners and sleeve valves for a pair of opposite cylinders and as a crosshead guide for the piston member operable within said pair of cylinders.

9. A two-stroke engine comprising a casing, a shaft operably mounted in said casing, cylinders in two similar groups facing each other across said casing, sleeve valve members operable in'said cylinders, double-ended piston members each operable in a pair of corresponding cylinders of said groups; and mechanism for the interconversion of reciprocatio and rotation operably connecting said piston members and said sleeve val/ve members with said shaft, the strokes of said sleeve valve members being shorter than, but as frequent as and timed substantially with the 2,216,342 y strokes of. said piston members, permitting said piston members to be shorter `and said engine I more compact and of less weight than would bers with said shaft, the' strokes-bf said sleeve o substantially withthe strokes of said pistons, and means for eliminating excessive clearance from said driving mechanism. i

valve members being shorter than, but as fre. quent as and timed substantially with the strokes of said piston members.

1l. An engine comprising a casing, a shaft operably mounted in said casing, cylinders spaced about vand `parallel with said shaft, sleeve valve members operable in saidvcylinders, pistons operable within said sleeve valve members, a wabbler Y operably mounted on said shaft on bearings' inclined thereto, operable connections between saidwabbler and said pistons, and means comprising operable connections between said wabblerand said sleeve valve members for driving saidsleeve valve members and for preventing rotation of said wabbler and for holding said wabbler substantially to its true geometric motion.

12. vAri engine comprising a casing, a shaft op- `erably mounted in said Icasing, cylinders spaced about and parallel with said shaft, sleeve valveV membersv operable in said cylinders, pistons reciprocable Within said sleeve valve members,

.means operably connecting said pistons and said shaft, mechanism for'driving saidr sleeve 'valve members on'strokes as frequent as and timed 13; An engine comprising a casing, a shaft operably mounted inl said casing, cylinders spaced about and parallel with said shaft, sleeve valve members operable in said cylinders, pistons operable Within said sleeve valve members, 4means. operably connecting said pistons and said'shaft,`

mechanism for driving said sleevelvalve'members from said shaft, and means for eliminating excessive clearance from said driving' mechanism and comprising a piston and cylinder,v a springV urging the piston outwardly from said cylinder,

and-a check valve for trapping oil withins'aid cylinder.

,14. In a parallel cylinder engine having a shaft and cylinders spaced about and parallelthereto, a fuel supply' system comprising a cam on said shaft, fuel pump units radiallyvdisposed about and driven by said cam and extending across the -heads of said cylinders.- and fuel injection nozzles inserted thru said'fuelV pump units into said cylinder heads.

15. An engine comprising a casing,` bearings supported by said casing, a shaft operably mounted in said bearings, cylinders in two groups facving-each other across "saidcasing, sleeve valve members having ports and operable in said cylinders, piston members operable Within said sleeve valve members, oil control rings on said piston members, and mechanism for the interconversion of reciprocation and rotation operably connecting said piston members and said sleeve valve members with said shaft, the strokes of said sleeve valve members being asv frequent as and timed in advance but substantially with the strokes of said piston members permitting said piston members to b e shorter than would otherwise be possible by the telescopic effect and preventing said oil control rings Vfrom everpassing over said ports.

16. Anengine comprising' a shaft, cylinders spaced about and parallel tov said shaft, sleeve valves operable in said cylinders, pistons operable within said sleeve valves, and means` for reciprocating both said pistons and said sleeve valves upon rotation of said shaft, the strokes of said sleeve valves beingrshorter than, but as frequent as and timed substantially with thecorrespond- Ying strokes of said pistons, said means comprising rollers operablyseated in said pistons and in saidV sleeve valves, and a cam member xed upon said shaft and operably engaging all of said rollers. y I i 17. 'In an engine having a shaft, a double-ended piston members operably connected to said shaft, and two similar groups of cylinders facing each other: integral tubular members each serving as movable cylinder liners and sleeve valves for a pair of opposite cylinders, and as a crosshead guide for the piston .member operable within said pair of cylinders, and means for driving each of said tubular members on strokes as frequent 4as and timed substantially with the strokes of the corresponding double-ended piston member.

` EDWIN S. HAH..

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