US2911964A

US2911964A - Internal combustion engines

Info

Publication number: US2911964A
Application number: US528902A
Authority: US
Inventors: Ford L Prescott; Edward A Hulbert
Original assignee: Continental Aviation and Engineering Corp
Current assignee: Continental Aviation and Engineering Corp
Priority date: 1955-08-17
Filing date: 1955-08-17
Publication date: 1959-11-10
Anticipated expiration: 1976-11-10

Description

F. L. PRESCOTT ETAL 2,911,964

INTERNAL COMBUSTION ENGINES 5 Sheets-Sheet 1 Nov. 10, 1959 Filed Aug. 17. 1955 l'l l l INVENTORS FORD L. PRE S COTT EDWARD A. HULBERT BY ATTOR Nov. 10, 1959 Filed Aug. 17, 1955 3 Sheets-Sheet 2 INVENTORS FORD L. PRESCOTT By EDWARD A. HULBERT ATTORN S Nov. 10, 1959 Filed Aug.

F. 1.. PRESCOTT T L INTERNAL COMBUSTION ENGINES 3 Sheets-Sheet 3 INVENTORS FORD L. PRESCOTT BY EDWARD A.HULBERT ATToRN S United States Patent INTERNAL COMBUSTION ENGINES- Application August 17, 1955, Serial No. 528,902

8 Claims. (Cl. 123 -41.65)

This invention relates to an internal combustion engine construction and more particularly to the so-called H-type two-stroke cycle engine, generally used in military tanks,

rail cars, and power generators and having an improved structural compactness and operating efliciency.

The engine structure. here disclosed relates generally to' H-type engines in which cylinders on each side 'of an engine case are conjoined by connecting rods to a central crankshaft. In some cases, separate crankshafts for the separated cylinders are further conjoined to another,'the output, crankshaft. In the instant invention, the cylinders are arranged vertically, though they may be disposed horizontally, if desired, each cylinder having two opposed pistons operable therein. The pistons are connected to rocker arms which are in turn connected by links to the crankshaft. A single engine unitcomprises a pair of parallel cylinders with four operating pistons therein conjoined by suitable rocker arm linkage to a single centrally arranged transverse crankshaft. Multiple engine units may be arranged in an engine case or housing, one by the other, all serving a single transverse cranckshaft.

There are some especial advantages in the instant construction which are among the objects ofthe invention. As will be seen in the drawings and noted in the specific description given below, the engine unit is made extremely compact, uniform and symmetrical. All of these characteristics improve the efficiency and expand the utility of the engine. There are no open or void spaces, no lost or waste areas that consume or require limited space in the engine chamber of vehicles. The cubical'content of the engine is held to a minimum, achieving more horsepower per unit weight and volume. v v v A further and highly desirable advantage is that the instant invention provides only a single crankshaft to serve any four or multiple of four pistons. This structural feature markedly reduces engine noise, chatter and rattle, particularly at low or idling speeds, as compared to current engine constructions in which duel geared crankshafts are required. In crankshaft arrangements of the latter type, engine noise frorn'gearing is almost impossible to eliminate especially at idling and low speeds. As the engines grow older in use, thenoise increases and efficiency decreases. Such construction is completely absent from the instant invention.

It is therefore an object of the invention to provide in an internal combustion engine an arrangement of parallel cylinders on each side of an engine crankcase and preferably separate therefrom; to provide dual opposed pistons in each cylinder therein; to provide a single output crankshaft operatively connected to all pistons; to provide an integrated engine structure of reduced cubic content; and to provide an economical, practical'and efiicient engine structure embodying these inventive improvements. I n a Additional objects and structural features of the invention will become more'apparent from the description given below. For a visual understanding'of the'invenf tion, reference is made to'the accompanying drawings'in which like p'arts are referred to by like reference numerals throughout the several views illustrating a preferred embodiment of the invention, and in which- Fig. 1 is a side elevational view of the engine embodying the inventive construction.

Fig. 2 is a vertical cross sectional view through a single engine unit of the engine of Fig. 1.

Fig. 3 is a top plan view of the engine of Fig. 1, partially in section.

As indicated in the drawings, the engine structure 10 comprises a crankcase 11 (see Fig. 2) to which an upper rocker arm housing 12a and a lower rocker arm housing 12b are secured by studs and nuts or other means as at 13. Cylinders 14 are secured by studs or bolts 15 to either the upper or lower housing aforesaid as shown and the free end is preferably slidably mounted at the other housing within 0 ring seal guides 14a. An upper housing cover 16 and a lower housing cover or pan 17 are installed on the upper and lower rocker arm housings respectively by bolts 18 or other suitable means.

An accessory gear case 20 of conventional construction is installed at one end of a cranckshaft 21 which exscribed presents a compact, roughly cubical shape, due

to the position of the cylinders and rocker arm housings relative to the crankcase. I

A fuel injector 30 is mounted in each cylinder wall 25 to supply fuel into the midpoint of a cylinder bore 31.

In addition, each cylinder is provided with an annular in- 7 take passage 32 and an annular exhaust passage 33.

Each passage is open to a port 34 opening into the cylinder bore 31.

Two opposed reciprocating pistons 38 are operable in each cylinder bore 31, the fuel charge from the fuel injector 30 being directed between them, into the combustion chamber 38a formed thereby. A link member 46 is preferably rigidly secured to a piston pin 41 conventionally pivoted in each piston 38, and its free end is pivotally secured to an end 42a of a rocker arm 42. The other end 42b of the rocker arm 42 is pivotally secured to a connectingrod 43, which in turn is supported by a crankpin 44 of the crankshaft 21. This connecting rod is preferably of a slipper rod type, permitting it to pivot relative to the crankpin while still being secured thereto,

and also permitting relative angular displacement of the slipper rods connected to the same crankpin. v

The rocker arm 42 is pivotally mounted on a shaft 50 carried in a pintle means 51. Through-bolts 51a pass from the upper block of pintle means 51 through the lower block, and are adapted to take the explosion force of the-pistons 38 acting on the rocker arms 42.

It will be noted that in a single engine unit of two spaced parallel cylinders 14, the upper piston 38 of one cylinder is connected by links 40, rocker arms 42, com necting rods 43 and crankshaft 21 to the lower piston of the other cylinder, whereby the two pistons reciprocate in The crankcase 11 is a. separate component structure I V and is spaced from the cylinders 14 and is substantially central ,of the engine, running axially with the crankshaft.

conventional opposedpiston engines, makes possible a through-scavenge or uniflow scavenge of the exhaust gases from the cylinder. -One piston of a cylinder serves as an intake valve and the other piston as an exhaust valve. The connecting rods to the pistons ofone cylinder are placed at an average or center line angle of 160 to '175 degrees to each other rather than at 180 degrees, by offsetting the crankshaft. relative to the rocker arm ends 42b. The two cranks of the crankshaft are shown asangularly spacedsubstantially 180 degrees. In operation, the offset anglecauses one piston to lead. the other, in the same cylinder, by a phase angle of to degrees, of crankshaft rotation. The leading piston serves as the exhaust valve and the lagging or following piston serves. as the intake valve. is thus provided between exhaust opening and intake opening, and a supercharge periodis provided betweenexhaust closing and intake closing. This arrangement serves to thoroughly scavenge and also to supercharge the cylinder, resulting in high power output and low fuel con- A blow-down period 1. In an opposed piston type internal combustion engine comprising a plurality of separable component engine structures; namely, a pair of engine cylinder structures, opposed pistons operable in each of said engine cylinder structures, a crankcase structure spaced from and disposed intermediate said pair of engine cylinder structures, a crankshaft supported by the aforesaid crankcase structurepand rocker: arm housing structures secured to opposite faces of said crankcase, said rocker arm housing structures being-respectively disposed in parallel planes extending parallel to the crankshaft'axis having lateral extensions overlying the ends of said cylinder structures sumption. It will be observed that varying the angular position of the cranks relative to each other and different from the 180 degree spacing as recited above will result in varying the phase angle between the pistons operable in the same cylinder. In practice the cranks are spaced generally about 170 to 180 degrees apart.

The engine is lubricated by means of a forced lubrica tion system which passes the lubricant from rocker arm shaft 50 to the link member 40, the piston pin 41, the piston 14 and up the cylinder bore 31. The lubrication system is such as is well known in the art and has been previously applied in air cooled engines. Oil coolers 23, forming a component part of the lubricating system, are arranged at the two flywheel end corners of the engine.

The flywheel and cooling fan assembly 22 isenclosed by a cooling fan housing secured to the end of the crankcase opposite the accessory gear case, and comprises a crankshaft mounted flywheel 70, to the peripheral edge of which is affixed a series of spaced vanes 72 comprising the cooling fan unit 74. Air drawn in is passed past the cylinder air cooling fins 26 between baffles 78 into the space lying between the cylinder and the engine crankcase, indicated as a whole by reference character 101, where the air may sweep past the wall of the crankcase 11 from which it is drawn into the lower unit 74 and is passedout of the engine through a discharge outlet 80, as indicated by the arrow in Fig. 3. Likewise cooling air is drawn through the cooler 23 and thence di-- with the pistons and their associatedlinkage provide high-- ly efficient power transmission. Reduced engine noise is a direct result of the single crankshaft arrangementachieved by the instant engine structure. The absence of valves and their attendant camshaftsandgearing coupled to the crankshaft contributes to space saving and efficiency;

Having described our invention, it will be apparent to those skilled in'the art to which this invention pertains that various modifications and changes may be made" without departing from'the spirit of the invention or from the scope of the appended claims.

We claim;

and providing cylinder supporting means, rocker arm mechanisms'ineach ofsaid rocker arm housing structures and operable in planes containing the cylinder axes and normal to the crankshaft axis, said rocker arm mechanisms connected with the pistons in said cylinder structures and with said crankshaft, each .ofsaid cylinder structuressecured to the lateral extensions of said rocker arm housing structures.

2. An opposed piston type internal combustion engine comprising a plurality of separate component engine structures; namely, a pair of engine cylinder structures, op-

posed pistons'operable in each of said engine cylinder structures, a crankcase structure spaced from and disposed intermediatesaid pair of engine cylinder structures, a crankshaft. supported by the aforesaid crankcase structure, rocker .arm housing structures secured to opposite faces of said crankcase which. are respectively disposed in parallel .planes extending parallel to the crankshaft axis and are laterally extended to overlie the ends of said engine cylindenstructures, rocker arm mechanisms in each of said rocker arm housing structures and operable in planes containing the cylinder axes and normal to the crankshaft axis, said rocker arm mechanisms connected with the pistons in said cylinder structures and with said crankshafheach of said cylinder'structures bolted rigidly to one of said rocker arm housing structuresand anchored to said other rocker arm housingwith a sliding connection permitting relative movement between said cylinder and said last mentioned rocker arm housing structure.

3. An opposed piston/type internal combustion engine comprising'a plurality of separate component engine structures; namely, a pair of engine cylinder structures, opposed pistons operable in each of said engine cylinder structures,'-a crankcase structure spaced from and disposed intermediate said pair of engine cylinder structures, a crankshaft-supported by the' aforesaid crankcase structure, rocker arm housing structures secured to opposite faces of said crankcase which are respectively disposed in parallel planes extending parallel to the crankshaft axis and are laterally extended-to 'overliethe ends of said engine cylinder structures,- -rocker arm mechanisms in each -of said rocker arm housing structures and operable in planes containing the cylinder axes nad normal to the crankshaft-axis, said rocker arm mechanisms connected with the pistons in said'cylinder structures and with said crankshaft, each of said cylinder structures bolted rigidly to oneof said rockerarm housing structures and anchored to said other rocker 'arm' housing with a sliding connec-'- tion permitting relative movement between said cylinder and said last mentioned rocker arm housing structure; said sliding 'connectionbetween said cylinder and rocker arm structure comprising -a circular opening telescopingly receiving the outer end portion of said cylinder whereby to provide a sliding fit therebetween;

4. An opposedpiston'type internal combustion engine comprising 1 a-plurality -of;separable component engine structures; namely, a pair of engine cylinder structures, .opposed pistonsoperable-in' each of said engine cylinder structures, a crankcase structure located substantially medially of and spaced from'said pair of engine cylinder structures, a crankshaft supported by said crankcase structure and dispose'dwith its axis normal to anengine plane containingtheuaxes of both said cylinder structures, and

means connecting each of said opposed pistons of both said cylinder structures to said crankshaft and comprising a rocker arm, a link connecting one end of the rocker arm to said piston and a connecting rod connecting the other end of the rocker arm to said crankshaft, said crankshaft having a pair of cranks which are disposed substantially 180 degrees out of phase, said connecting rods constructed and arranged to connect one piston of the opposed piston assembly of one engine cylinder structure and the diagonally located piston of the opposed piston assembly of said other engine cylinder structure to the same crank of said crankshaft, so that when said pistons of one engine cylinder structure are at approximately the peak of their compression stroke, the pistons of said other engine cylinder structure are approximately at the bottom of their power stroke, a rocker arm housing structure secured to opposite parallel faces of the crankcase and having lateral extensions of overlying the ends of both engine cylinder structures said lateral extensions providing cylinder supporting means, said rocker arms pivotally supported by said rocker arm housing structures.

5. An opposed piston type internal combustion engine comprising a plurality of separable component engine structures; namely, a pair of engine cylinder structures, opposed pistons operable in each of said engine cylinder structures, a crankcase structure located substantially medially of and spaced from said pair of engine cylinder structures, a crankshaft supported by' said crankcase structure and disposed with its axis normal to an engine plane containing the axes of both said cylinder structures, and means connecting each of said opposed pistons of both said cylinder structures to said crankshaft and comprising a rocker arm, a link connecting one end of the rocker arm to said piston and a connecting rod connecting the other end of the rocker arm to said crankshaft, said crankshaft having a pair of cranks which are disposed substantially 180 degrees out of phase, said connecting rods constructed and arranged to connect one piston of the opposed piston assembly of one engine cylinder structure and the diagonally located piston of the opposed piston assembly of said other engine cylinder structure to the same crank of said crankshaft, so that when said pistons of one engine cylinder structure are approximately at the peak of their compression stroke, the pistons of said other engine cylinder structure are approximately at the bottom of their power stroke, a rocker arm housing structure secured to opposite parallel faces of the crankcase and having lateral extensions overlying the ends of both engine cylinder structures, said lateral extensions providing cylinder supporting means pintle means carried by said rocker arm housing structure for rotatably supporting each of said rocker arms, and tension bolt means for bolting together a pair of pintle means, one in each of said rocker arm housings.

6. In an opposed piston type internal combustion engine comprising a pair of engine cylinder structures, opposed pistons operable in each of said engine cylinder structures, a crankcase structure located substantially medially of said pair of engine cylinder structures, a crankshaft supported by said crankcase structure and disposed with its axis normal to an engine plane containing the axes of both said cylinder structures, and means connecting each of said opposed pistons of both said cylinder structures to said crankshaft, a fan housing secured to one end face of said crankshaft and having an air intake and exhaust, a fan in said fan'housing and driven by said crankshaft and disposed to move air generally in a direction parallel to the crankshaft axis, said cylinder structures being spaced laterally from said crankcase structure to provide an air space, said cylinders having fins, and air baffle means associated with said finned cylinders to confine the air flow in heat transference relation with the cylinders, said fan operable to induce air flow laterally past the cylinders and in heat transference relation with respect to the crankcase.

7. An opposed piston type internal combustion engine comprising a pair of engine cylinder structures, opposed pistons operable in each of said engine cylinder structures, a crankcase structure located substantially medially of said pair of engine cylinder structures, a crankshaft supported by said crankcase structure and disposed with its axis normal to an engine plane containing the axes of both said cylinder structures, and means connecting each of said opposed pistons of both said cylinder structures to said crankshaft, a fan housing secured to one end face of said crankshaft and having an air intake and exhaust, a fan in said fan housing and driven by said crankshaft and disposed to move air generally in a direction parallel to the crankshaft axis, said cylinder structures being spaced laterally from said crankcase structure to provide an air space, said cylinders having fins, and air baflle means associated with said finned cylinders to confine the air flow in heat transference relation with the cylinders, said fan operable to induce air flow laterally past the cylinders and in heat transference relation with respect to the crankcase, an oil cooler supported on said engine and having an air inlet and an air exhaust means, said oil cooler air exhaust means openly communicating with said air space between said cylinders and said crankcase.

8. In an opposed piston type internal combustion engine comprising a plurality of separate component engine structures; namely, a pair of engine cylinder structures, opposed pistons operable in each of said engine cylinder structures, a crankcase structure spaced from and disposed intermediate said pair of engine cylinder structures, a crankshaft supported by the aforesaid crankcase structures, and rocker arm housing structures secured to opposite faces of said crankcase which are respectively disposed in parallel planes extending parallel to the crankshaft axis and are laterally extended to overlie the ends of said engine cylinder structures, rocker arm mechanisms in each of said rocker arm structures and operable in planes containing the cylinder axes and normal to the crankshaft axis, said rocker arm mechanisms connected with the pistons in said cylinder structures and with said crankshaft, a gear case structure, and a cooling fan housing structure, said last two mentioned structures respectively secured to two other opposed faces of the crankcase structure lying in parallel planes extending normal to the crankshaft axis, each of said cylinder structures secured to said rocker arm housing structures.

References Cited in the file of this patent FOREIGN PATENTS 918,281 France Oct. 14, 1946