US2222294A - Internal combustion engine - Google Patents

Description

. Nov.l9,1940.

E. s. HALL i 2,222,294

INTERNAL COMBUSTION ENGINE Filed Feb. 8, 1958 2 S heet's-Shee t 1 INVENTOR.

ATTORNEYS.

Nov. 19, 1940.

I E. SJFIIALL 2,222,294

INTERNAL COMBUSTION ENGINE 2 Filed Feb. 8, 1938 2 Sheets-Sheet 2 Fiq-i M- IN V EN TOR.

ATTORNEYS.

Patented Nov. 19, 1940 UNITED STATES INTERNAL COMBUSTION ENGINE Edwin S. Hall, New Haven, Conn. Application February 8, 1938, Serial No. 189,401

2 Claims.

engines of the type having cylinders parallel to the shaft, commonly called barrel type? or round engines, and is particularly concerned with the normal type of round engine, (1. e. that type having double-ended piston members serving two similar roups of. working cylinders with the reciprocating-rotary mechanism between them), tho some of the features of the invention are applicable to other types of engines, aswill be evident. This application is a continuation in part of my copending application Serial Number 67,017 filed March 4, 1936.

An object of this invention is to provide an 35 efiicient and compact engine capable of delivering an unusually large'amount of power for its bulk with extremely smooth operation. To this end, the invention consists of a normal round engine with preferably an odd number of 2G double-ended piston members serving two groups of working cylinders, operating on the two-stroke cycle, with air for combustion furnished by separate blower means.

In two-stroke engines, the piston may over- 35 run both intake and exhaust ports at the same time, but uniflow scavenge is preferable with 4 intake at one end of the cylinder and exhaust at the other. In normal round engines, uniflow scavenge can be obtained by using piston-controlled ports for intake and valves for exhaust, or vice versa. An object of this invention is to provide a normal barrel engine operable on the two-stroke cycle with uniflow'scavenge, with both ports in the cylinder walls and a valve 5 system. Preferably the intake may be thru piston-controlled ports, the valve system handling exhaust. but the direction of scavenge might be reversed if desired, with the valve system handling intake and the pistons uncovering exhaust ports.

Relative to the valve system, an object of the invention is to provide a very simple system comprising two disc valves, each serving an entire group of cylinders, and mounted on eccentrics on the shaft so as to contribute to the dynamic balance of the engine, and so driven that the speed of the valve relative to the port sealing means is relatively slow during high pressure portions of the cycle, but*very much faster during opening and closing of the ports, to provide rapid opening and closing of the ports and to permit very large port openings for free flow of the gases. Further objects are to provde improved driving, sealing, cooling, and oil control means for disc valves.

. (31. 123-58) This invention relates to Internal combustion Good scavenge and favorable combustion conditions can be obtained with the intake ports long enough radially to have a nozzle effect and tangentially inclined to give an orderly swirl to the scavenge air as it enters the cylinders. It 5 is also desirable to be able to machine all ports. Objects of this invention are to provide these conditions by using individual cylinders each with a ring of tangentially inclined intake pOlbS opening into the cylinder, and to provide uniform distribution of the scavenge air by serving all the ports of the several cylinders of each group from a common windchest thru which the cylinders extend.

The two windchests must be supplied with air at pressure somewhat greater than atmospheric, from the blower system. Positive displacement blowers could be used, but centrifugal blowers have less bulk for the amount of air delivered, and are therefore preferred. The most serious problem involved in the use of centrifugal ablowers is to provide a sufiiciently sturdy drive, and it is an object of this invention to provide an improved method of driving and mounting centrifugal blowers. To deliver enough air at the required pressure to scavenge a 1000 H. P. enine may require more than 200 H. P., and the step-up gearing must deliver that power continuously with the blower speed ten times engine speed or more. Gear tooth loads are very severe and impeller inertia forces are terrific; the gearing must be protected from shock resulting from irregular operation of the engine shaft. An object of this invention is to reduce the gear tooth loading to a fraction of what it would be ordinarily by providing a system of multiple blowers, instead of the usual single blower. Further objects are to provide a simple and symmetrical system of gearing in which each gear can be maintained in alignment by being mounted on a pair of adequate bearings, cantilever loading being avoided; and to provide cushion and clutch means to avoid shock on the ears; and to provide means for assembling and mounting each blower in a manner insuring c0!'- s5 rect meshing of its drive pinion.

In round engines of both the normal and opposed-piston types, the driving and disposition of such accessories as oil and water pumps, gen erator, tachometer. etc., have been something of a problem. An object of this invention is to provide 'a workmanlike system of driving the accessories of a barrel engine in a manner permitting their convenient and accessible location. Within each group of cylinders, a plurality of [iii bevel gears are mounted on their own bearings and driven by a single gear on the engine shaft,

and radial'dri've shafts each associated with its accessory or group of accessories are inserted 5 between the cylinders to connect with the bevel gears, the accessory or group thereof being mounted on a flange on the outside of the engine in a convenient and accessible position.

In any two-stroke engine, it is desirable to use fuel injection to avoid loss of unused fuel thru the exhaust. An object of this invention is to provide a fuel injection system for a barrelengine with radially arranged pump units driven from a cam on the engine shaft, each pump unit being associated with its own nozzle, both pump and injection nozzle being easily accessible. Long high-pressure pipes areavoided and uniform action is assured. A further object is to provide 20 of the fuel pumps.

Another-object is to provide improved accessibility to various parts and accessories of a barrel engine, and a further object is to provide an improved general arrangement for a barrel engine comprising a series of unit sub-assemblies so constructed that they may be assembled in order as follows: the engine mechanism proper including the pistons as an operable mechanism; the cylinders in two groups, one at each end of the engine casing; a valve and accessory assembly at each-end; and the blower unit at one end and the power offtake gearing or coupling at the other.

Another object is to provide for axial fiow of the cooling medium thru the jackets of the individual cylinder units to insure their uniform cooling and to insure especially the cooling of the port bridges. The wabbler case is jacketed to assist in cooling the oil and to form a water manifold connecting the inner ends of all cylinder water jackets, while the valve housings, also water-jacketed to assist in cooling the valve, form the water manifolds connecting the outer ends of the cylinder water jackets. Circulation of the cooling medium by pumps may be from the 45 wabbler casing jackets outwardly thru the cylinder jackets to the valve housings, or vice versa,

as desired, suitable radiators being included in the circuit as usual.

These and other objects and features of the 50 invention will be more apparent from the following description in connection with the drawings,

in which: Fig. 1 is a longitudinal sectional view of the rear portion of the engine, it being under-' stood that the'forwardend is similar and the 55 various parts symmetrically arranged to those shown excepting only the blower unit which serves both rear and forward groups of cylinders. As usual, in longitudinal sectional drawings of barrel engines, projections of some of the parts behind the plane of the drawing are omitted to avoid unnecessary confusion. Fig. 2 is a transverse section on the line 'I'--T of Fig. 1, showing the cylinder intake port arrangement Figs. 3V and 3M are sectional views of the disc valve system, taken on the lines VV and M-M of Fig. 1'.

Fig. 4 is an enlarged view of a portion of Fig. 1 showing the particular type of port sealing means used in connection with the disc valve. Fig. 5

- is a development of a portion of one of the sealing 70 rings and its spring ring.

Referring to the drawings, engine shaft is operable inball bearings ll mounted in casing 12. Wabbler I315, mounted on bearings 14 on shaft ID, the axis of the wabbler and its bearings being 7 inclinedtornado; the shaft. Wabbler'arms l5 means for controlling the timing of the operation have suitable operable connections with piston members l6 which are reciprocable in guide surfaces l8 in casing I2 while piston rings I1 slide in cylinders 26.

Cylinders are individual units, each bolted to casing 12 by bolts 2| and having an annular water jacket 24 and integral combustion chamber openwater'jacket to direct the air as it enters cylinder 20. Ports 22 are piston-controlled and ports 23 are controlled by disc valve which is rotatable on eccentric 3| fixedon shaft 16. Disc valve 30 has peripheral gear 32 engaging internal gear 33 carried by valve casing. member 34 which member also has ports 35 opposite to and larger than combustion chamber ports 23. Ports 35 discharge into manifold 36 which is fastened to casing member 34. Ports 31 thru valve disc 30 successively connect each of ports 23 with its corresponding port 35. Chambers 38 and 39 within valve disc 30 may be filled with cooling liquid. Combustion chamber ports 23 are sealed relative to the face of valve 30 by rings 29, identical in construction with ordinary piston rings, and urged against the face of valve 30 by springs 38 augmented by the gaseous pressure being confined. Valve ports 31 when not in alignment with ports 23 are kept closed relative to the interior of the valve house ing by sealing plate 21 which is resiliently held against the face of, valve 30 by springs 26 seated in casing member 40.

Casing member 40 is part of the housing for valve 30 and is bolted to cylinders 26 by bolts 4|. Casing member 40 has concentric cylindrical walls 42 and 43 engaging casing l2 and forming an annular chamber 44 enclosing cylinders 26 and forming a common windchest to supply ports 22 5| enclosed in casing members 52 and 53, the

latter having formed therein the diffuser by which the kinetic energy of the air deliveredby the impeller is converted into pressure. Impeller 5| is fixed on shaft 54 having an integral drive pinion 55. Bearings 56 and 51, mounted in casing member 52, are fixed on shaft 54 on either side of pinion 55 and are thus favorably situated to maintain pinion 55 in correct alignment without undue deflection under load, and concentric with casing member 52. 4

Casing members 52 of the blower units 56 pilot into holes in the blower drive housing whose two members 60 and 62 carry bearings 63 and 64 on which blower drive gear 65 runs. Thus accurate meshing of pinions 55 with gear 65 is assured. Drive housing member 66 is piloted onto bearing 6| of shaft l0, locating the blower drive assembly concentric with shaft l0. Housing member 60 is fastened to valve casing member 34 by bolts 66.

Splines 61 fixed on shaft l6 engage internal splines on inner torque cushion member 68 which is surrounded by outer cushion member 69. Cushion members 68 and 69 have interlocking teeth between which springs 16 are tangentially.

outwardly by light springs I? to engage their shoe portions with the inside of gear 85, forming a friction clutch by which gear 65 is driven.

Accessory drive gear 8!! is fixed on shaft I and engages a plurality of accessory driven gears 8! each of which is mounted in ball bearings 82 and 83 secured to inner wall 42 of valve casing member Q0. Various accessories such as the oil pump 84 indicated in Fig. 1, are mounted on bosses formed on outer wall 13 of casing member 30. Each accessory has its own drive shaft 85 extending between adjacent cylinders 29 thru a suitable oil-tight housing across windchest it and engaging a driven gear M with a splined connection 7 Fuel pump cam 90 is fixed on shaft l8. Surrounding fuel pump 90 is a cage member 95 fitted into inner wall d2 of casing member 68 in a manner permitting angular adjustment of cage member 9i by any convenient means. Cage member St has radial cylinders 92 .one for each cylinder 26 of the group. In each cylinder 92,

cam follower 93 is reciprocable with its roller engaging cam 96. Each cam follower 93 is provided with segmental shoe 9t Whose ends are a free fit in peripheral groove 95 in cage member di. Each shoe 93 engages a pushrod 96 which extends radially outward thru a suitable oil-tight housing across windchest at between adjacent cylinders 29, to operate fuel pump 9'0 which is associated with an injection nozzle 98 for each combustion chamber of the several cylinders 2d. Push rod spring as is provided to return push rod 96 and cam follower 93.

Engine casing l 2 is provided with water jackets H) which assist'in cooling the oil and also serve as a manifold communicating with the individual water jackets 2 of cylinders 20. The valve housing is also water-jacketed and the casing member 18 serves as a manifold to connect the outer ends of the individual water jackets 2d of cylinders 25 The bridges 25 between intake ports 23 are also water-jacketed.

In assembling the mechanism, wabbler i3 is assembled on. bearings Hi on shaft id, and the shaft iii in bearings H in casing 52. Then piston members i 6, followed by wabbler arms i5 and their operable connections, may be assembled 'thru handholes in casing l2. The engine mechanism proper is now assembled as an operable unit. Then cylinders 20 may be bolted to casing 52.

An accessory drive gear 8d and fuel pump cam 9b are assembled on each end of shaft it. Driven gears 85 and their bearings 82 and 3, and then push rods 96, springs 99, and cage member 9! with cam followers 93, are assembled in casing member 43, two such assemblies being bolted to cylinders 20. Accessories with their drive shafts 85, and fuel pumps 9? and nozzles 98 may then be added.

Eccentrics 35 are added to shaft H3, with valves 35? on them, and the valves are timed, and casings 3 t assembled and bolted to casings lii. Then bearing 65 and splined member 6? may be added to shaft If; and drawn up with the lock nut.

The blower drive unit assembled in casing members so and 62 may then be piloted onto bearing 6i, splines 6'7 mating with those of member 68, and the unit bolted to casing 36. Blower units 58 may be assembled to casing member 62 either before or after assembly of the'drive unit to casing 34. To assemble a blower unit 5b in casing 62, insert the pinion-containing end of the unit and hook it over gear 85, then move inwardly until casing 52 can pilot into the hole in casing 62, and press the pilot into place. Then bolt casing 53 to casing 62. With accurate machining of the parts, pinions 55 will be precisely located and held in the designed position relative to gear 65.

Manifold 36, in two parts, may then be assembled, and conduits 45 connected, after which the various controls and the exterior oil, fuel, and cooling system plumbing may be attended to. Operation.-Rotation of shaft l9 will be accompanied by reciprocation of. piston members l5 by the operable action of the wabbler mechanism in a known manner, details of which are not included in the present invention. Rotation of sh ft l0 will also drive blower units 59 in a manner hereinafter described, to deliver air thru conduits 65 to windchests id, and whenever the pistons uncover ports 22, the air is directed into cylinders 2i! by ports 22 in a manner causing a high-speed swirling action. Somewhat before ports 22 of a given cylinder are opened, its port 23 is opened by the motion of valve 30, permitting discharge of the exhaust thru ports 37 and 35 to manifold lid, so that when ports 22 open, the swirling scavenge can effectively clear the cylinder. Valve 36 is timed to close port 23 somewhat before ports 22 are closed by the piston, permitting the cylinder to be supercharged approximately to blower pressure. The operation of valve 30 is described in greater detail hereinafter.

With cylinder 28 scavenged and charged with air, the piston next compresses the air, and when near top center, cam 90 operates one of the radiating members of the fuel system as hereinafter described, to cause the corresponding nozzle 98 to inject a shot of fuel into the combustion chamber. The piston is driven downward again by the ensuing combustion and expansion of the gases, to repeat the cycle.

Since both groups of cylinders are working cylinders operating on the two-stroke cycle, an outside source of air for combustion must be provided. Splines it"! drive inner cushion member iiii'which drives outer cushion member 69 thru springs 70, these members comprising a spring coupling. The action of springs 72 augmented by centrifugal force acting on segmental shoe members H frictionally engages shoe members W with the interior of gear 65 to drive it, and drive gear 55 drives pinions 55 and impellers 5! at high speed.

Shock loading on the gear teeth'is avoided by the yielding nature of torque cushion springs ill, by the yieldable overload slip ability of clutch shoes 1i, and by the flywheel effect of gear 65 which resists sudden changes in velocity. However, even these comprehensive and effective means of protecting the gear teeth would not save them if the gears were severely overloaded as they would be if a single blower were used for so large an engine. Attempts to design a drive with reasonable gear tooth loads for such an engine have been unsatisfactory. A system of s ev eral smaller blowers in accordance with the present invention seems a much better way. Tooth loadings are reasonable, the symmetry of the drive system in helpful, and the method of mounting each gear on a pair of adequate bearings accurately located and rigidly supported, also contributes to success. action, increasing the torque capacity about as the square of the speed, is provided because it Centrifugal clutch v 50 the piston is at 'top center la twice as fast, and big, as if the. valve same speed,

' Just the same if the valve large diameter gears.

more nearly suits the requirements than any fixed capacity clutch can.

Any breathing system suitable for a two-stroke engine could be used in the normal two-stroke round engine, but uniflow scavenge with ported intake and exhaust controlled by valves is preferred. Any suitable valve system could be used including poppet valves, but the disc valve system illustrated has numerous advantages. As

shaft l0 rotates, valve 39 is carried around bodily on eccentric 3| while engagement of gears 32 and 33 rotates valve 39 on eccentric 3| at a speed slower than that of shaft l9 and in the opposite direction, as can be understood from astudy of Fig. 3. The number and proportions of ports 31- in valve 30 are arranged to cooperate with the trochoidal movement of the valve to produce the I desired port timing. The peculiar advantages of (radial distance of port 23 from shaft 10) (radius of gear 33) (number of cylinders in the group) -1 of port 23 when the piston is at bottom center is proportional to:

(radial distance of port 23 from shaft l0)+ (nsdius of gear 33) (number of cylindersin the groupi 1 From the former ratio it is obvious that if gear 33 had the same radius as the cylinder pitch of the first ratio would be zero,

circle, the value the instantaneous axis of valve signifying that 40 disc 30 would be the axis of port 23 when the piston is at top center". Practically speaking, the valve. would stop when the pressure is at peak. a desirable condition from the standpoint of the sealing rings and their wear. This condition could be provided by constructing gear 33 on a separate disc axially spaced and beyond manifold 39 from the valve proper. with gear 33 larger than the pitch circle of ports 23 as shown, the velocity of valve 39 relative to port 23 when is still quite slow, but reversed in direction from that during most of the cycle. From the second ratio it is obvious that the larger gear 33 is made, the faster the ports in a two-stroke engine will open and close and the larger the ports in the valve can be made.

i and 3 I With proportions such as those of Figs. the speed of the valve when the ports open and close, relative to the ports 23, is about four times that when pressures are at peak. Port action the ports can be twice as were an ordinary rotary valve running concentric with the shaft at the (i. e. one-eighth shaft speed for nine cylinders with the proportions shown). The

breathing ability can thus be about four times more free.

Thus the applica ion of the eccentrically driven disc valve to the two-stroke engine gains new and important ends. and the advantages would hold were used for intake instead of for exhaust, or for both. The peculiar motion of the valve is in every way advantageous for two-stroke cycle operation, and the advantages are greater by'the use of relatively The speed of the valve The speed of the valve face relative to the center relative to the port sealing means and the easing against which the valve is pressed by cylinder pressure, is relatively slow during the high pressure portions of ,the cycle, while the speed during port opening and closing is several times faster, providing quick port opening and closing and permitting very large ports.

The action of sealing rings 29 relative to their concentric grooves in casing member 40 and relative to the face of valve 90, is similar to that of ordinary piston rings, except that initial contact of rings 29 with valve 30 is insured by spring rings 28. (.ontact having been made, the pres-' sure trying to leak past rings 29 presses them outward against the outer walls of their grooves, and gets under them to press them against the face of valve 39, precisely as the pressure gets behind a piston ring to press it against the cylinder wall and groove. The rotary and orbital movement of valve 39 induces rings 29 to rotate slowly in their grooves, preventing scoring, insuring even wear and perfect seal.

The masses of eccentrics 3| and valves 30 are designed of right amount so that the couple produced by their rotation with shaft ill will offset the couple arising from piston reciprocation, to produce practically perfect mechanical balance, in a known manner. In the fuel system, cam 99 operates successively the cam followers 93,- and each drives its pushrod 96 outward to operate the corresponding pump 91, and a shot of fuel is injected thereby into the appropriate combustion chamber thru nozzle 99. Spring 99 returns cam follower 93 and pushrod 99 after the injection stroke. has its own return spring, as is known.

To adjust the timing of the fuel injection, cage member 9| is adjusted angularly by any suitable control means, shoes 9l stili riding on their respective push rods 96. When the axes of cam followers 93 aresomewhat' out of line with the axes of pushrods 99, the length of stroke of fuel pumps 91 is slightly shorter, but the discrepancy is very small and of no significance in viewof the fact that the pump is so constructed that only a small central portion of its piston stroke is effective anyway. a

The various accessories are driven by gears and SI thru their several radiating shafts 95. Of these accessories, the water pumps may circulate cooling fluid thru radiators of well-known types, pumping the fluid into jackets 89 in casing l2, from whence it flows axially outward thru the several jackets 24 of individual cylinder units 29 to jackets in casing members 49 and 34, when it may be returned to the pumps and radiators. Alternately, the flow could be reversed. One of the most constricted parts of the circuit is where the water goes thru the intake port bridges; the velocity at these points will therefore be high, and the bridges eflectively cooled. All water system gaskets are clamped between plane surfaces so that leakage canbe prevented. The combustion chamber proper of each cylinder 20 is not directly water-jacketed; it is desirable in a Diesel engine for the combustion chamber to run rather hot. This condition could be avoided if the engine were to be run on the Otto cycle.

Other accessories may include the oil pumps, one of which is indicated at 93. Oil is circulated thru shaft ID as an oil main, which can be tapped wherever necessary. Oil is fed out thru eccentric II to flll chambers 38 and 39 in valve 39 by centrifugal action, to assist in cooling the valve, the

Pump 91 7 tion as expressed in 2,222,294 a overflow from theinner lip of chamber 39 being returned to the sump from which it can be sent thru oil coolers by the scavenge pump in a known manner.

Having thus described the invention, its construction, assembly, and operation, it is obvious that all the objects as stated herein have been attained. The invention has been described as a normal round engine substantially complete with its various accessories as a uniquely compact source of smooth and eihcient power. Certain features of the invention are applicable to other types of engines and it' is understood that they may be so applied, construction and in the'arrangement of the various parts of the invention may be made, without departing from the spirit or scope of the inventhe following claims.

I claim:

l. A two-stroke normal barrel engine comprising a shaft, cylinders parallel to said shaft, piston members operable in said cylinders, a wabbler mechanism operably connecting said piston members to the central portion of. said shaft, a pair of eccentrics fixed on said shaft toward the ends thereof, plate valves rotatable on said eccentrics, said eccentrics and valves being so constructed and arranged that the centrifugal couple thereof during operation will be opposite to and substantially equal to the inertia couple produced by operation of said piston members with said wabbler mechanism, means fordriving and that other changes in the plate valve members,

said valves comprising gears on said valves and gears fixed relative to said cylinders and meshing therewith, and means for providing uniflow scavenging thru said cylinders, said uniflow scavenging means comprising inlet ports tangentially inclined in the walls of said cylinders and controlled by said pistons, and exhaust ports in the heads of said cylinders and controlled by said plate valves.

2. A two-stroke engine comprising a shaft, cylinders parallel to said shaft, piston members operable in said cylinders, a wabbler mechanism operably connecting said piston members to the central portion of said shaft, ports in the heads of said cylinders and spaced about said shaft in a plane normal thereto, a pair of plate valve members controlling said ports, ports thru said and means for driving said valves uniformly and at constant rate relative to said shaft so as to cause said valve ports to register successively with said cylinder ports and in such a manner that the speed of said valve relative to said cylinder ports will be relatively slow when the pressures in said cylinders are high, and several times faster whenever said valve ports are registering with said cylinder -ports, said valves and their drive means being'so constructed and arrangedas to produce a centrifugal couple during operation opposed to the couple resulting from the inertia of said piston members.

S. HALL.

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