US1732578A

US1732578A - Internal-combustion engine

Info

Publication number: US1732578A
Application number: US82952A
Authority: US
Inventors: Garuffa Egidio
Original assignee: Individual
Current assignee: Individual
Priority date: 1925-01-23
Filing date: 1926-01-22
Publication date: 1929-10-22
Anticipated expiration: 1946-10-22

Description

Oct. 22, 1929. GARUFFA INTERNAL COMBUSTION ENGINE Filed Jan. 22, 1926 atented Oct. 22, 1929 um'r so STATES EGIDIO GABUFFA, OF MILAN, ITALY ETERNAL-COMBUSTION Enema Application liled January 22,1926, Serial: li'o. 82,952, and in Italy January 23, 1925.

The present invention relates to internal combustion engines and more particularly to a two-cycle engine.

While the present invention may be used ti tor other purposes, it is particularly adapted tor air-craft engines where the weight of an engine is of particular importance. In such uses, a two-cycle engine is preferred on account of its low weight per horse power Heretoiore, four-cycle engines have been employed in spite of the extra weight due to the tact that previous two-cycle engines have not been suciently dependable to warrant their adoption. Further, in two-cycle enlll gines, the scavenging is not thorough and there is considerable waste of gas in the oper ation. These and other obstacles render the usual type of such engine much less desirable than the iour cycle engines.

The present invention overcomes these difticulties by providing a source t compressed air for thoroughly scavenging the cylinder and an independent source of compressed air adapted to be saturated with gasoline which will is iorced into the cylinder subsequent to the scavenging operation and slightly prior to the closing oi the exhaust port. Tn this way there is no waste oi" fuel; at the same time the scavenging may be as thorough as desired iii A suitable blower or tan having a plurality oi stages may be utilized so that the number of stages may be changed as the altitude in creases whereby a substantially constant pressure may be maintained in the air and fuel 35 mixture supplied to the cylinders. In this manner the power of the engine remains constant and its operation is not affected by the varying changes in height and the correspond ing changes in the density of the atmosphere.

An object of the present invention is to provide a compact motor particularly suited tor air-craft uses which has a high volumetric thermal ei'ficiency and capable of maintaining a constant output at high altitudes.

Another object of theinvention is to provide a thorough scavenging of two-cycle engines without waste of fuel and to supply to the engine substantially constant quantities oi iuel irrespective of-the density of the at- W mosphere.

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Another object of the invention is to rovide an inexpensive aircraft motor whic is simple in construction and effective in operation and not subject to breakdowns.

Other and further objects of the invention will be obvious upon an understanding of the illustrated embodiment about to be described; and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

. ig. 1 is a sectional view through one cylinder of the motor showing the arrangement of the scavenging and exhaust ports;

Fig. 2 is a work diagram illustrating the opening and closing of the various ports;

Fig. 3 is a diagrammatic illustration of the compressed air and fuel mixture supply systems;

Fig. 4 is a side elevational view partly diagrammatic of a motor embodying the present invention; and

Fig. 5 is a diagrammaticillustration of a gas turbine for operating the blower or fan.

Referring to the drawings and more par ticularly to Fig. 1, there is shown a cylinder U having an exhaust port a and scavenging ports a and h. The ports a and h are posi tioned so that the port 6 is slightly higher than the exhaust port 8. That is, the piston uncovers the port prior to the exhaust port on its downward strolre and closes the exhaust port prior'to the closing of the port 5 on its compression stroke. The lower port a of each cylinder is fed with compressed air supplied by a suitable fan or blower at a predetermined pressure. The pressure tube Ta connected to the fan or blower Q, may be used for this purpose. The upper port I) is fed with a rich fuel mixture which may be air and gasoline under the control of a distributor which is preferably a rotary one as shown at V. The distributor opens and closes the tube Tb leading to the port h in timed relation with the movement of the piston.

The two tubes Ta and Tb may be. fed by a single fan or blower 9, it being understood that a suitable fuel mixture is injected into the tube Tb. During the downward stroke of the piston the tube Tb isclosed by the distributor V. As the exhaust port 8 is uncov- Bill ered air is admitted under pressure through the tube Ta and exhaust port a which scavenges the cylinder thoroughly due to the shape of the piston head. The irregular shape of the piston deflects the air toward the head of the cylinder and forces out the burnt gases. Since there is no fuel being delivered to the cylinder at this time, an escape of the compressed air through the exhaust port 1s unimportant, therefore all of the exhaust gases may be removed without waste of fuel. As the piston reaches the end of its stroke and begins its compression stroke, the distributor V admits a rich fuel mixture into the cylinder .just prior to the closing of the exhaust port and continues for a short time after the exhaust port a and port a are closed. In this way any desired fuel charge may be supplied without waste.

The work diagram of this operation is shown in Fig. 2; The circle having its center at 0, represents the path of the crank and its vertical diameter M represents the stroke of the iston. During the stroke portion AB, the port 6 is closed by the distributor which feeds the cylinder with fuel. During the portion B-C compressed air is sup lied through port a and during portion O the exhaust portion 8 is open. By drawing a horizontal line through the points A, B, C D and E, the total height h of the supply and scavenging ports and the total height h of the exhaust ports are obtained. The point A is considerably above the point D, representing the closing of the fuel port 6 and exhaust port s,respect1vely. During the down stroke of the piston, the port I; is closed and no fuel enters the cylinder. When the piston reaches the line D-D the exhaust port is open and the exhaust continues through the angle DOD while air is supplied during the period represented by the angle BOBK By means of the distributor V controlling the fuel port I).

the admission of air and gasoline begins at the point F and continues through the stroke represented by the angle FOA. In this manner the initial scavenging is efiected with air only and leakage is of little importance. The mixture is introduced shortly before the exhaust port closes and continues for a short period after the closing. The fuel supply and the scavenging being effected by two independent gaseous currents of different qualities produces the best conditions for obtaining complete scavenging and prevents loss of fuel through the exhaust port. It permits complete elimination of smoke and the complete filling of the combustion chamber with the fuel mixture.

While any type of fan or blower may be used the preferred embodiment contem lates a turbo-compressor operated by a suitable motor or by an exhaust gas turbine as shown in Fig. 3. The blower may be connected through the engine crank shaft 0+0 through the pinion R on the shaft XX of the blower in any suitable manner.

Preferably the turbo blower has four stages (I-IV) and can deliver the quantity of air necessary for scavenging the cylinder at a predetermined pressure. The rotation of the blower may be effected by the turbine T operated by the exhaust gases. In order to prevent too great an angular velocity the turbine is of a two-stage construction. It receives the exhaust gases from the engine through the exhaust pipe 8 and discharges the gas at S Since the blower is also connected to the engine through crank shaft OO, two separate drives are provided and a suitable clutch I permits the blower to 'be driven directly by the engine through the pinion R when desired. Accordingly if the turbine T fails to function the blower may be driven by the englue or if greater power is desired than afforded by the turbine T, both the turbine and the engine may be used or the engine alone.

In order to obtain constant power at diiferent. hei hts, it is desirable that the engine should e fed with a constant weight of air and also with a constant weight of gasoline. The present blower accomplishes this by having the valves Z and Z While flying at considerable altitudes the air may be taken from the fourth stage through valve Z which increases the pressure. The volume may be increased simultaneously through the speed change gear on shaft X-X,which preferably permits the blower to operate at three different angular speeds, M, n, n.

As volumes and pressures are nearly related to square of annular speeds both will increase, passing from n to n according to the relation and passing from n to n according to relation Increasing the volume and pressure also increases the power required to operate the blower; but the discharging exhaust gases possess the necessary energy and in any event direct coupling with the engine can be used if desired.

Atomization of the gasoline is effected in the tube Tb by an atomizer V which is adjustable to vary the amount of fuel fed as desired. Gasoline is supplied from a receptacle H through tube 2. Pressure in this receptacle is preferably greater than the scavenging pressure so as to obtain very fine atomization which is facilitated by the heat of the compressed air.

Fuel is supplied to the receptacle H by any suitable means here shown as a pump W.

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pump may be driven either by the en glue or by a small air propeller if used in aircraft. The tube 2 connects the atomizer V with the lower portion of the receptacle and a tube 3 is connected to a suitable compressor which delivers air through the automatic valve y from one of the engine cylinders. The automatic valve 4 is adapted to discharge any excessive pressure in the receptacle. The tank H is also provided with a pet cock 6 for discharging gasoline and a monometer 5.

Une form of engine is shown in Fig. lhaving a motor casing A with-a base portion B. Six cylinders are shown, 0,, C C C C and C The gas turbine T is shown at the front end thereof for driving the fan or blower S. A mechanical drive direct from the -engine.is shown through pinion R. The

speed control gear Co and the tubes Ta, Tb are shown connected to the respective cylinders by T branches. The fuel supply tank H and atomizer V are properly connected as described hereinbefore.

In Fig. 5', the gas tubine T is shown arranged adjacent the turbo-blower S on shaft O-O. The speed control gear Co is mounted on the front end of the shaft OO and drives the hollow shaft O,-----O telescoped about the shaft O-O. i

As various changes may be made in the above embodiment without departing from the spirit of the invention, it is to be understood that all matter herein set forth is to be interpreted as illustrative and not in a limiting sense. I

Having thus described my invention, I claim:

1. A two-cycle internal combustion engine comprising a plurality of cylinders, a turboblower having a plurality of stages therein, means for supplying air from said blower to said cylinders from different stages of said blower, aridmeans for driving said blower at variable speeds to increase the volume of air delivered to the cylinders independently of the speed of the engine.

2. A two-cycle internal combustion engine comprising a plurality of cylinders, a turboblower having a plurality of stages therein, means for conducting air from different stages of said blower to said cylinders for scavenging same, and means for conducting air from said blower to an atomizer for supplying fuel to said engine.

3. A two-cycle combustion engine comprising-a cylinder, a turbo-blower having a plurality of stages therein and means for supplying air from said blower to said cylindcr from different stages of said blower for scavenging same, means for driving said blower at variable speeds to increase the vol ume of air delivered to the cylinder, and devices for connecting different stages of said blower with an atomizer for supplying fuel to the cylinders.

4. Amulti-cylinder engine the combination of air compressing means for supplying air under pressure to said cylinder, a turbine operated by. the exhaust gases for driving said compressing means, and devices for connecting said compressing means directly to the engine to be driven thereby.

5. A multi-cylinder engine the combination of a multistage air compressing means for supplying air under pressure to said cylinders from different stages thereof, means operated by the exhaust gases for driving said compressing means, and a clutch for connecting said compressing means directly to the engine to afford greater power for the operation thereof.

6. A multi-cylinder engine for aeroplanes and the like, the combination of compressing means for delivering compressed air to said cylinders, devices adapted to be operated by the exhaust gases for driving said compressing means, said compressing means being adapted to be driven also by the engine, and a mechanism for connecting said means either to said engine or to said devices.

In a two-cycle engine of the class described, the combination of a-distributor for supplying a mixture to said cylinder, a reservoir for liquid fuel and means for maintaining the pressure in said reservoir greater than the scavenging pressure, said means comprising a connection with one of said cylinders to render the explosive pressure effective thereon.

8. In a two-cycle internal combustion engine, the combination of a multistage compressor for supplying scavenging air to said engine, a distributor for supplying a fuel mixture to said cylinder, a reservoir having a supply of liquid fuel, and means for maintaining a pressure in said reservoir greater than the scavenging pressure in said engine to assure proper operation of said distributor at all times. 7

9. In a two-cycle intepnalcombustion engine, the combinationrof a multistage compressor for supplying scavenging air to said engine, and for supplying'air to said distributor, a distributor for supplying a fuel mixture to said engine, a reservoir for fuel and means connected with a cylinder head for maintaining a pressure in said reservoir adequate to supply fuel to said distributor at all pressures to which the distributor is subjected.

Signed at Milan, Italy, this 4th day of January, 1926.

EGIDIO GARUFFA.