US2039103A - Engine - Google Patents

Description

INVENTOR.

ATTORNEY.

J. MEYER ENGINE Filed Dec. 26, 1951 Patented Apr. 28, 1936 ENGINE Andre J. Meyer, Detroit, Mich., assignor to Continental Motors Corporation, Detroit, Mich., a corperation of Virginia Application December 26, 1931, Serial N 0. 583,288

3 Claims. (Cl. 123171) This invention relates to internal combustion engines and has particular reference to engines of the sleeve valve air cooled type, although many features of my invention are applicable to other types of engines.

My invention is especially suited for engines of the aircraft type wherein the air stream is conveniently employed to obtain engine cooling. In such arrangements it is customary to arrange the engine cylinders so that their axes are substantially transverse to the direction of air stream flow so that the air stream sweeps across the outer ends of the cylinders. With such arrangements, the forward portion of the cylinder head, or that portion first receiving contact with the air stream is cooled much more effectively than rearward portions of the cylinder head since the air stream becomes heated by the forward portions during travel of the air across the outer ends of the cylinders. This uneven cooling tends toward engine difficulties and inefiiciencies, particularly in connection with engines of the sleeve valve type which ordinarily employ cylinder head structures provided with re-entrant portions extending inwardly of the respective cylinders. With such engines, this uneven cooling eifect tends to distort the cylinder heads resulting in a binding tendency in the sleeve valve means and also resulting in improper cooling of the engine.

A further difliculty experienced in connection with engines of this type resides in reverse-d cooling of the cylinder heads by reason of a disturbing influence produced by the screw bolts or other fasteners employed to secure the cylinder heads on the respective cylinders. These fasteners customarily project outwardly from the cylinder heads in the path of the air stream thereby preventing an efiicient flow of air in contact with the heated parts.

It is an object of my invention to provide improvements in engines of the aforesaid types so as to overcome the aforesaid difiiculties. A further object of my invention resides in the provision of a cylinder head structure constructed and arranged to substantially compensate for tendencies of the air stream to cool the rearward portion less efiiciently than the forward portion. A further object of my invention in its more specific character resides in the provision of a cylinder head structure having a plurality of spaced fins extending outwardly into the path of the air stream, the fins providing greater cooling area for the rearward portion of the cylinder head structure than for the forward portion thereof.

A further object of my invention resides in the provision of a cylinder head structure wherein the fastening devices are located away from the path of the air stream across the cylinder ends whereby to materially increase the cooling efiiciency of the engine by obtaining a relatively smooth air stream flow.

A still further object of my invention resides in the provision of improved means for piloting a cylinder head structure in association with a cylinder structure so as to obtain improved alignment between the cylinder bore and re-entrant portion of the cylinder head structure. This feature of my invention relates to the provision of a cylinder head structure having an undercut annular flange adapted for seating on the end of the cylinder and providing a cylindrical pilot engaging a companion pilot formed with the cylinder structure, the pilot being located relatively remote from the cylinder bore whereby it is very effective in properly aligning the cylinder and cylinder head structures.

Other objects and advantages of my invention will be apparent as this specification progresses, reference being bad to the accompanying drawing in which:

Fig. 1 is a vertical elevation sectional view through a typical cylinder of the engine,

Fig. 2 is an elevation plan view of the cylinder head structure alone, and

Fig. 3 is a sectional elevation View along the line 3-3 of Fig. 2 and showing one of the fastening devices for the cylinder head structure, and a portion of the associated cylinder structure.

In the drawing reference character A represents the cylinder structure having a cylinder bore it and a plurality of annular cooling fins ii spaced axially of cylinder l around the outside of the cylinder structure A. The structure A has an outer face i2 extending transversely with the axis of cylinder ill and terminating outwardly in a cylindrical pilot l3. Located within the cylinder Ill is the sleeve valve means, herein illustrated as a single sleeve valve B formed with the usual intake and exhaust ports it and i5 respectively for cooperating in the usual manner with fuel mixture intake means It and exhaust gas conducting means ll respectively. The particular form of sleeve valve means is not important in this invention and I have therefore not illus- Operating within the sleeve valve B is the usual piston 58 and connecting rod I9.

For closing the outer end of cylinder I0, I have provided a cylinder head structure C which, in order to secure good heat conducting qualities, may be formed of a wall extending across cylinder Hi and having the annular flange 2| formed with radially outwardly extending annular cooling fins 22 spaced axially of cylinder H2. The flange 2i is also undercut to provide an annular seating portion 23 adapted to seat on outer face l2 of the cylinder structure A. The undercut seating portion 23 also forms the annular or cylindrical pilot 24 adapted to engage the pilot l3 as shown in Fig. 1. The cylinder head structure is preferably of the solid wall type and is formed with the generally cylindrical shaped depending portion 25 extending inwardly within and spaced from cylinder I 0 so as to form a sleeve pocket receiving the upper end of the sleeve valve as shown.

The wall 26 has an outer floor 26 from which are extended outwardly therebeyond a plurality of cooling fins 21 preferably substantially aligned in the direction of the air stream indicated by arrows 23, the fins extending transverse to the cylinder axis. As shown in Fig. 1 the fins 21 are of less height at the forward portion 29 of the cylinder head structure than at the rearward portion 38 so as to provide a greater fin area rearwardly than forwardly and thereby compensate for tendencies of said air stream to cool the rearward portion less efficiently than the forward portion. In Fig. 1, I have illustrated the fins El as tapering progressively inwardly toward the oncoming air stream, thereby obtaining a progressive or gradual differential in the. cooling effect to substantially offset the differential cooling effect aforesaid. It will be understood that I have illustrated only one cylinder of the engine and it is frequently customary to form the cylinders radially about the axis of a common crankshaft (not shown), with the air stream flowing toward the exhaust side of the cylinders as illustrated in Fig. 1.

The flange M is formed with a circumferential series of spaced holes 3! formed with outer counterbores 32 adapted to receive the screw bolts or fasteners 33 with the heads 34 thereof respectively substantially housed within the counterbores 32. With such construction it will be noted that these fasteners do not present any disturbing eifect to the air stream as the air flows smoothly and efiiciently across the cylinder head structure between fins 2?. The inward threaded portions of fasteners 33 engage correspondingly threaded recesses formed in the outer end of the cylinder block structure as shown in Fig. 2. The wall 26 is formed with one or more recesses 35 for receiving the spark plugs 36. The spark plugs have their terminals adapted to project into the combustion chamber 31.

It will be noted that the companion piloting portions l3 and 24 are located relatively remotely from cylinder bore Ill whereby a relatively small amount of piloting is very eifective in aligning the depending portion 25 accurately with respect to cylinder Hi, assisted by the undercut face 23 engaging outer face E2 of the cylinder structure. As a result of my improved piloting construction, the cylinder head is accurately aligned and .does not tend to become distorted on being seated by the fasteners 33 and thus there is no binding action on the sleeve valve means which would otherwise tend to be produced.

By reason of my annular flange 2| formed with the spaced annular fins 22, I have provided a very efficient cooling for the cylinder head structure, the fins 22 forming substantially a continuation of the fins H formed on the cylinder structure.

Furthermore by graduating the area of fins 21 with respect to their proximity to the air stream 28, I have provided a cylinder head structure which is substantially uniformly cooled, thereby obviating tendencies toward distortion and binding of the sleeve valve means which would otherwise result under localized heating. The depending portion 25 is preferably of the solid wall type in the interests of eflicient heat conductivity, as distinguished from the jacketed type of re-entrant portion.

Instead of having faces 23 and E2 in direct seating engagement, these faces may have a gasket interposed therebetween but this is not deemed necessary especially for the air cooled type of engine as illustrated.

Various changes and modifications will be apparent from my disclosure and it is not my intention to limit my invention to the specific arrangements of parts as shown and described.

What I claim as my invention is:

1. In an internal combustion engine of the air cooled type having a cylinder structure provided with a cylinder, a cylinder head structure closing one end of said cylinder and having an annular flange seated on the outer end of the cylinder structure, said flange carrying a plurality of outwardly extending cooling fins and having a plurality of counterbored holes extending therethrough, and headed fasteners extending through said holes for connection to said cylinder structure, the heads of said fasteners lying substantially within said counterbores respectively to provide smooth air flow across said cylinder structure in the vicinity of said fins.

2. In an internal combustion engine of the air cooled type having a cylinder structure provided with a cylinder, a cylinder head structure closing one end of said cylinder and having a wall extending across the outer end of the cylinder structure, said wall having a plurality of counterbored holes therethrough and a plurality of cooling fins adjacent thereto, headed members in said holes connecting the cylinder head structure and cylinder structure, said members having their heads positioned in said counterbores to facilitate flow of cooling air intermediate said fins.

3. In an internal combustion engine of the air cooled type having a cylinder structure provided with a cylinder, a cylinder head structure closing one end of said cylinder and having a wall extending across the outer end of the cylinder structure, said wall having a plurality of counterbored holes therethrough and a plurality of cooling fins adjacent thereto, headed members in said holes connecting the cylinder head structure and cylinder structure, said members having their heads positioned in said counterbores to facilitate flow of cooling air intermediate said fins, said wall also having a plurality of circumferentially outwardly extending cooling fins.

ANDRE J. MEYER.

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