US2047026A - Air-cooled engine - Google Patents

Description

y 1936- F. GOSSLAU AIR COOLED'ENGINE Filed Sept. 26, 1933 3 Sheets-Sheet l y 1936. F. GOSSLAU vAIR COOLED ENGINE Filed Sept. 26, 19:53

3 Sheets-Sheet 2 v July 7, 1936. F. GOSSLAU AIR COOLED ENGINE Filed Sept. 26, 1953 3 Sheets-Sheet 3 K 43 W my Patented July 7, I 1936 AIR-COOLED, ENGINE Fritz Gosslau, Berlin-Charlottenburg, Germany,

'assignor to Siemens & Halske, Aktiengesell- "halt, Siemensstadt, near Berlin, Germany, a corporation of Germany Application September 26, 1933, Serial No. 690,975 In Germany September 27, 1932- 10 Claims. (Cl. 123-471) My invention relates to an air-cooled multicylinder engine provided with a cooling blower.

The attempts hitherto made to increase beyond a certain measurethe power of air-cooled internal combustion engines with cylinders in line have failed in that in the direction of flow the cylinders at the rear could not be, cooled to the desired extent. As a result of'this defective cooling of the individual cylinders the utilization of the power of the entire engine was, therefore, limited. To overcome this drawback it has already been proposed to arrange a blower on the crank shaft, but the difficulties of an ununiform cooling could .not be surmounted. It has, therefore; been proposed to provide each cylinder with a blower. Such an engine, however, is heavy and complicated. The conditions of air supply to the individual blowers cannot be controlled.

The methods heretofore employed in developwith cylinders in line over 200 H. P. didnot practically come into use. Greater powers are reserved to air-cooled stationary radial cylinder acre-engines or water-cooled engines with cylinders in line. The drawbacks of the air-cooled radial cylinder aero-engine lie in its high head resistance, those of the water-cooled engine with cylinders in line in its tendency t'o cause a loss of the cooling water and in its heavy weight, drawbacks which an air-cooled engine with cylinders in line of considerable .power would not present.

The object of my invention is tq provide an air-cooled engine with cylinders in line which are actually uniformly cooled by a single blower, without impairing in any way the thermal and aero-dynamic efliciency.

The invention involves the driving of the cool.-

ing blower by the crank shaft of the motor through a transmission gear, and the supplying of the cooling air to a receiver which is so de signed as to cause a substantially uniform pressure to prevail at diflerent inlet ports leading therefrom, such inlet ports being arranged in air-guide jackets surrounding the respective cylinders and being of such form that cooling air is circulated around the individual cylinders and so distributed that the difierent portions of each cylinder receive different quantities corresponding with the amount of heat to which such diiierent portions are exposed in accordance with their different distances from the lower dead centre of the piston. In this case the receiver in conjunction with the inlet ports provides for a uniform distribution of the cooling air, the form 0% the ports for the most economical consumption of air and the air-guide jacket for the thermally effective flow of the cooling air.

In the accompanying drawings two embodiinents of my invention are illustrated in diagrammatic form.

Figs. 1 and 2 show in transverse sectional elevation and in horizontal section respectively an engine with two rows of inverted cylinders set at an angle to one another and the arrangement 01. a receiver at the outer side of each row of cylinders.

Fig. 3 represents a transverse sectional front elevation through a cylinder pair in Fig. 4. showing a modified form of air supply; N

Fig. 4 represents a horizontal section through the cylinder Fig. 3 similar to the one shown in Fig. 2, and

Fig. 5 represents a side elevation of this modification, partly in central longitudinal section.

In Figs. 1 and 2, I denotes the crank case, 2 and 3 the two rows of inverted cylinders set at an angle to one another. A blower 4 driven by the engine through a transmission gear (not shown) is located in the upper part of the crank case. The blower 4 supplies air through the ducts 5 and 6 to receivers I and 8 located at the outer side of each row of cylinders. The crank case has a compact and substantially oval cross-section. It, therefore, takes up but a small space and is resistant to deformations and to oscillations of the walls. The fuselage 32 maybe easily adapted to the. engine and has a suitable crosssection.' The crank case is built integral with the individual air-guide jackets 9 and ill of which one is provided for each of the cylinders. 2' and 3 in the two rows and which are connected with one another to form an integral body. The crank case is considerably stiffened by the air-guide jackets and protected against deflection. The air-guide jackets may, however, be also mounted on the crank case in the form of a separate block. Such an arrangement also stiiiens the crank to a great extent. The air-guide jackets are provided with inlet ports H and I2, shown portly in ature than with the surfaces exposed to a low temperature as seen in Fig. 1. The cross-section of the inlet ports is considerably larger in the neighborhood of the cylinder head than at the lower end or the cylinder. Byadapting the crosssection-of the inlet openings to the diflerent cross-sections of the ducts a greater iamountyotcooling air may be supplied per unit-of time to the hotter head of the cylinder than to: thelower end thereof, where lower temperatures prevail. Exhaust ports l3 and H are located at the opposite side of me air jackets. 'this'case c into the space between the rows of cylinders.

The walls of the receivers 1 and 8 are formed partly of the crank case and partly of the airg uide jackets. In this manner the crank case is effectively cooled and at the same time heat is also abstracted from the outer surface of the air-guide jackets. The outer walls I5 and I6 of the receivers 1 and 8 are built integral with the crank case and, consequently, also serve to stiffen the crank case.

The cooling air from the receivers 1 and 8 is not only directed around the cylinders but also passes along the valves, that is first along the exhaust valves l9 and 20 through outlet openings placed at the lower end of the receivers as indicated at I! and H3. The pipe connections 2| and 22 of the exhaust valves I9 and 20 are provided with cooling ribs. The cooling air on passing along the exhaust valves gets hotter and may, consequently, preheat the fuel mixture flowing through the inlet pipes 23, 24.

The pipe connectionsZl and 22 of the exhaust valves l9 and 20 do not form directly the valve seats for these valves but the valve seat is rather surrounded by a particularly good heat conducting jacket which comes into contact with the cooling medium. By the insertion of the heat conducting part an effective cooling of the ex haust valve is ensured without thereby causing other important parts to operate under unfavorable working conditions. In this manner the heat produced at any point in the neighborhood of the exhaust valve is carried off at once so that no other parts, for instance the liner of the cylinder, are affected. This heat conducting part with which the exhaust valve is provided is denoted by the numeral 22'.

The inlet andiexhaust ports ll, I2, l3 and M of the cylinder'eooling jackets extend from the cylinder head downwardly to the lower end of the jackets, and thus impair the stiffening of the crank case to a certain degree. This is compensated by providing the cylinders 25 with flanges 26 which are situated at the valve ends of the liners and cover the outer ends of the cooling jackets. Insthis manner the structure of the airguide jackets is further stiffened. The fastening of the cylinders is, for instance, effected by bolts 21.

The arrangement of the flanges 26 in the neighborhood of the cylinder head does not only serve to increase the stifieningof the crank case with the cooling jackets, but it also compensates for the deformations caused by the heat. Aircooled cylinders whose flanges are situated in the neighborhood of the lower dead centre expand to such. an extent in operation as a result of the heat that the valve clearance becomes greater, since the center of rotation of the valve rocker upon the expansion of the cylinders is shifted away from the end of the push rods. Since too greats. valve clearance may give rise to serious valve. ruptures, high power air-cooled internal combustion engines are equipped with a device for compensating the valve clearance. This, however, results in complicated, expensive and heavy constructions, whereasin an arrangement according to the invention provisions for compen- "sating the valve clearance need not be made.

The cylinders expand toward the -crank shaft,

which has no infiuenceiipon the position of the center of rotation for the valve rocker.

cooling air jackets to which the cylinder flanges are securedremain sufficiently cool sothat they The' 2,047,026 the air may escape, if desired, through diffusers do not cause a displacement of the center of rotation for the valve rocker.

In case the cooling jackets should nevertheless expand as a result of a slight amount of heat present therein to such an extent that the valve clearance might be impaired, this expansion is compensated for in the engine according to the invention by the fact that the cooling air, which gets hot upon being directed around the cylinder, strikes the push rods and .heats the latter to such a degree that the expansion of the cooling air jacket is effectively compensated.

Since the cooling air on passing through the cooling jacket takes up a considerable amount of heat its volume increases. In order to avoid a throttling of the cooling air flowing around the cylinders and, consequently, an increase of power required for the blower, the cooling jackets are excentrically arranged around the cylinder. They are in the neighborhood of the air inlet ports II and I2 disposed nearer the cylinder wall than they are in the neighborhood of the air exhaust ports l3 and I4.

Consequently, the cooling ribs 30, 3|, which are adapted to the diameter of the cooling jacket, are of smaller height at the air inlet ports than at the air exhaust ports, as clearly shown in Fig. 1.

Instead of supplying the cooling air through means located on the outside of the two rows of cylinders, a central receiver located between the two rows may be employed. This modification is shown in Figs. 3 to 5.

In Figs. 3 to 5, I denotes the crank case of the internal combustion engine. 2 and 3 are the two rows of cylinders set at an angle to one another. The cooling blower 4' delivers cooling air through the pipe connection 5' and the pipe 6' to the receiver 1' which is located between the two cyl-' inder blocks. The cylinders are provided with cooling fins 8' and cooling jackets 9. The cooling air flows from the receiver 1' through the ports I 0' between the cooling jackets of the cylinders and through the ports I I to outside atmosphere. By causing the air to flow into the receiver at the end opposite to the cooling blower 4' a favorable position of the exhaust ports is attained, since the air may flow off in a direction opposite to the direction of flight.

In the hitherto known engines cooled by blowers the cylinders could receive different quantities of cooling air depending upon their position with respect to the cooling blower since the air on reaching the last outlet port decreases in pressure considerably. The cylinder worst cooled diminishes the power of the entire engine. As compared to the previously known engines cooled by blowers the invention shows how a greater number of cylinders may be uniformly supplied with cooling air so that the output of the engine may be developed to a much greater extent.

I claim as my invention:

1. An air cooled internal combustion engine comprising a plurality ,of. cylinders arranged in series, a cooling air jacket enclosizg each cylinder and having inlet and outlet openings for per-' decreases in width from the valve end of the cylinder toward the crank end thereof, an air receiver common to the series of cylinders and their jackets, bounded at least partly by those portions of the jackets in which their iiilet openings are located, so as to maintain direct communication for cooling from said receiver to the respective 75 jackets, and a blower for delivering cooling air into said receiver.

2. An air cooled internal combustion engine comprising two rows of cylinders, those of one row set at an angle to those of the other, a cooling air jacket enclosing each cylinder and having inlet and outlet openings for permitting cooling air to be forced around its respective cylinder, the inlet opening of each of said jackets being in the form of a slot which decreases in width from the valve end of the cylinder toward the crank end thereof, an air receiver extending along one side of each row of cylinders and their jackets, bounded at least partly by those portions of the jackets in which their inlet openings are located, so as to maintain direct communication for cooling air from said receiver to the respective jackets, and ablower for delivering cooling air into said receiver.

3. An air cooled internal combustion engine comprising two rows of cylinders, those of one row set at an angle to those of the other, a cooling air jacket enclosing each cylinder and having inlet and outlet openings for permittmg cooling air to be forced around its respective cylinder, the inlet opening of each of said jackets being in the form of a'slot which decreases in width from the valve end of the cylinder toward the crank end thereof, an air receiver arranged between said two rows of cylinders and their jackets, bounded at least partly by those portions of the jackets in which their inlet openings are located, so as to maintain direct communication for cooling air from said receiver to the respective jackets, and a blower for delivering cooling air into said receiver.

4. An air cooled internal combustion engine comprising two rows of cylinders, those of one row set at an angle to those of the other, a crank case, a cooling air jacket enclosing each cylinder and having inlet and outlet openings for permitting cooling air to be forced around its respective cylinder, said jackets being integral with said crank case and the inlet opening or each of said jackets being in the form of a slot which decreases in width from the valve end of the cylinder toward the crank end thereof, an air receiver extending along one side of each row of cylinders and their jackets, bounded at least partly by those portions of the, jackets in which their inlet openings are located, so as to maintaln direct communication for cooling air from said receiver to the respective jackets, and a blower for delivering cooling air into said receiver.

5. An air cooled internal combustion engine comprising a plurality of cylinders arranged in a series, a cooling air jacket enclosing each cylinder and having inlet and outlet openings for permitting cooling air to be forced around its respective cylinder, the inlet opening of each of said jackets being in the form of a slot which decreases in width from the valve end of the cylinder toward the crank end thereof, an air receiver common to the series of cylinders and their jackets, bounded at least partly by those portions of the jackets in which their inlet openings are located, so as to maintain direct communication for cooling'air from said receiver to the respective jackets, and a blower disposed at one end of said'receiver and delivering cooling air into same at the opposite end thereof.

6. An air cooled internal combustion engine comprising a plurality of cylinders arranged in series, a crank case, a cooling air jacket enclosing each cylinder and having inlet and outlet openings for permitting cooling air to be forced around its respective cylinder, said jackets being integral with each other and in stiffening relation with said crank case, the inlet opening of each of said jackets being in the form of a slot 5 which decreases in width from the valve end of the cylinder toward the crank end thereof, an air receiver common to the series of cylinders and their jackets, bounded at least partly by those portions of the jackets in which their inlet openings are located, so as to maintain direct communication for cooling air from said receiver to the respective jackets, and a blower for delivering cooling air into said receiver.

7. An air cooled internal combustion engin comprising a plurality of cylinders arranged in series, a crank case, a cooling air jacket enclosing each cylinder and having inlet and outlet openings for permitting cooling air to be forced around its respective cylinder, the inlet opening 20 of each of said jackets being in the form of a slot which decreases in width from the valve end of. the cylinder toward the'crank end thereof, an air ,receiyer common to the series of cylinders and their'jackets, bounded at least partly by those 2% portions of the jackets in which their inlet openings are located, so as to maintain direct communication for cooling air from said receiver to the respective jackets, said receiver being further bounded by a portion of said crank case and a so wall extending therefrom, and a blower for olelivering cooling air into said receiver.

8. An air cooled internal combustion engine comprising a plurality of cylinders arranged in series, exhaust valves for said cylinders, a 0001- $53 ing air jacket enclosing each cylinder and having inlet and outlet openings for permitting cooling air to be forced around its respective cylinder, the inlet opening of each of said jackets being in the form of a slot which decreases in width from the valve end of the cylinder toward the crank end thereof, an air receiver common to the series of cylinders and their jackets, bounded at least partly by those portions of the jackets in which their inlet openings are located, so as to maintain direct communication for cooling air from said receiver to the respective jackets, ports for directing cooling air from said receiver around said cylinderexhaust valves, and a blower for delivering cooling air into said receiver.

9. An air cooled internal combustion engine comprising a plurality of cylinders arranged in series, exhaust valves for said cylinders, heat conductive housings around said exhaust valves, a cooling air jacket enclosing each cylinder and having inlet and outlet openings for permitting cooling air to be forced around its respective cylinder, the inlet opening of each of said jackets being in the form of a slot which decreases in width from the valve end of the cylinder toward 60 the crank end thereof, an air receiver common to the series of cylinders and their jackets, bounded at least partly by those portions of the jackets in which their inlet openings are located, so as and then. jackets. bounded at least partly by those portions of the jackets in which their inlet openings are located, so as to maintain direct communication for cooling air from said receiver to the respective jackets, and a blower for delivering cooling air into said receiver.

FRITZ GOSSLAU.

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