US1772977A - Internal-combustion engine - Google Patents

Description

Aug. 12, 1930. P, ARRIGHI' 7 1,772,977

INTERNAL COMBUSTION ENGINE Filed Feb. 25, 1929 2 Sheets-Sheet 1 IN VEN TOR.

ATTORNEYS.

Aug. 12, 1930. P. ARRIGHl 1,772,977

' INTERNAL COMBUSTION ENGINE Filed Feb. 25, 1929 2 Sheets-Sheet 2 l LN 4 ATTORNEYS.

Patented Aug. 12, 1930 UNITED STATES, PATENT OFFICE,

PIETRO ARRIGHI, or SAN FRANCISCO, CALIFORNIAIASSIGNOR T ITALIEN-AMERICAN MOTORS me, or sen FRANCISCO, CALIFORNIA, A CORPORATION or CALIFORNIA" INTERNAL-COMBUSTION GINE Application filed February 25, 1929. Serial No. 342,579.

This invention relates to internal cembus-.

The present invention discloses that type of internal combustion engine in which a plurality of cylinders are arranged radially and parallel to a drive shaft, power being transmitted from the reciprocating pistons in the individual cylinders to the drive shaft through a series of connecting rods and crank shafts and a reduction gear drive, so that the drive shaft will be driven at what is ordinarily termed cam shaft speed.

A number of dili'erent methods of admit ting and exhausting the combustible mixtures has been employed in engines ofthis' character butthey have met with difficulties and inefiiciency.

The object of the present invention is to generally improve and simplify the construction of the valve mechanism in engines of the character described; to provide a single;

poppet valve for each cylinder and in combination therewith a single rotary valve which cooperates and functions in such a manner that each poppet valve will alternately function as an inlet and an exhaust valve, and further to provide means whereby the several poppet valves andthe single rotary valve may be directly driven and actuated by the drive shaft.

The valve mechanism as applied to an en-' gine of the character described is shown by drawings in which:

Fig. l is a central longitudinal section of the engine, said view showing the valve mechanism as applied, the section being taken on line I-I of Fig. 2.

Fig. :2 is a cross section'taken on line 'II ILFig. 1, F r r Fig. 3- is an end view partly broken away and partially'in section, the section portion being taken on line III'III--of Fig. -1.

Referring to the drawings in detail, and particularly to Fig. 1, A indicates a crank case to which is suitably secured a number of cylinders generally indicated at B; The cylinders are-disposed radially and parallel to a drive shaft generallyindicated atC;

way of illustration in the accompanying This shaft extends through the crank case and is journalled therein, as indicated at D, and it isdrivenin the following manner: Each cylinder is provided with a piston, such as shown at E, these pistons being provided with connecting rods F which in turn are connected with individual crankshafts,such as shown at G. Each crankshaft has ,se-. cur-ed thereon a spiral gear pinion H, andthe several pinions intermesh with a spiral gear K, which in tuIILlS keyed or otherwise secured tothe drive shaft C, the gear'ratio be tween the spiral gear pinions H and the spiral gear K being 2 to 1, so that the drive shaft will make one revolution to each two revolutions of the individual crank shafts. The drive shaft is, in other Words, driven at what is ordinarily termed cam shaft speed.

While a spiral gear drive is shown, itis.

obvious that a bevel or worm gear drive may be employed, the particular drive shown he I ing of no lmportance as it forms no part of the present invention. The present invention is directed to the valve mechanism whereby the combustible mixture is. admitted and exhausted from thev several cylinders. i The valve mechanism consists of a head member 2 whichis bolted or otherwise secured to the outer .ends of the cylinders, as indicatedat 3. The head member is provided with aplur ality of elbow-shaped passages, such as indicated at 4, the number of passages employed being equivalent to the number of cylinders,

the number in this instance being. 6 as clearly shown in ig. 2. A valve seat 5 is formed in the outer end of each passageand a poppet valve 6 of standard construction is adapted to seat thereon. Thestems of the poppet valves are disposed at right angles tofithe drive shaft C. They are spring seated, as indicated at/Wand they are lifted from their seats by aicam member generally indicatedat 8, this cam being secured to the drive shaft or formedintegral therewith, asshown. f

The drive shaft C is not only supported by the journal members D in the crank case, but it is also supported by journal members, such as indicated at '9 and 10, these journal members being mounted in the head 2. In other words,'- the drive shaft extends throughthe registers" withthe elbow-shaped passage 41s head member 2 and it serves three main functions, first that of driving the cam 8 whereby the poppet valves 6 are actuated, secondly that of supporting and driving a rotary valve generally indicated at 12, and third that of functioning as a portion of the inlet manifold, the drive shaft being hollow. or tubular at its outer end, as indicated at 11, to permit the incoming combustible mixture delivered by the carburetor 18 to pass therethrough.

The rotary valve is best illustrated in Figs. 1 and 3. It is first of all provided with an exhaust port 14, and secondly with an' inlet port 15, the port 15 being in communication with the carburetor and the tubular passage 11 by means of radial ports 16. The exhaust port extends transversely through the rotary valve, as shown in Fig. 1, so that when the valve indicated at 6 is open, for the purpose of exhausting, the exhaust gases can pass out through the elbow-shaped passage 4 in the direction of arrow a, then through the exhaust passage 14 and into an exhaust manifold indicated at 17, this manifold being in the form of a cover member 18 which retains the rotary valve against endwise movement, the cover being secured to the outer ends of'the cylin ders in any suitable manner, or as here shown by bolts 19.

By referring to Fig. 3 it will be noted that the inner end of the exhaust port 14 which elongated, as indicated at 14, as it extends from the point 19 to the point 20. This is necessary as registration must be made between the elbow shaped passage 4 and the port 14 during substantially the entire exhaust stroke of the piston. The outer end of the inlet passage 15 is similarly elongated, as shown at 15, see Fig. 3, as it extends from the point 21 to the point 22, the length of the port being such that registration will be maintainedv between the inlet port and the elbow. shaped passage 4 during the suction stroke of a piston.

The poppet valves employed in the present instance function alternately as inlet and as exhaust valves and it is accordingly necessary to maintain them in an open position both during. the exhaust and the inlet stroke. The.

cam 8 is accordingly shaped to maintain the valves open during this period, as clearly shown at 8 in Fig. 2, as it extends from the point 23 to the point 24.

The engine is intended to operate on the four-cycle principle, to wit, exhaust intake compression and firing, and as the drive shaft operates at cam shaft speed due to the gear ratios employed, the valves will remainopen during the exhaust and inlet stroke and they will remain closed during the compression and filing strokes.

When the engine is in operation, the drive shaft C rotates at cam shaft speed, and the poppet valves 6 will thus beopened in successive order and they will remain open during the exhaust and intake strokes.

The rotary valve 12 rotates in unison with the earn 8 as it is keyed or otherwise secured to the drive shaft and the exhaust port 14 will register with the respective cylinders during the exhaust stroke while the intake port 15 will register with the cylinders during their intake stroke. The combustible mixture, when admitted,'will of course becompressed in the usual manner and during the firing stroke the pressure exerted is transmitted through the several pistons to rotate the crank shaftsG and the spiral pinions H, and as these intermesh with the spiral gear K power is continuously transmitted to the drive shaft G.

The engine may be employed for any purpose desired, but it is particularly intended for aviation purposes and the like. In that case the propeller will be secured on the outer end of the drive shaft at the point indicated at 40.

An engine constructed in the manner disclosed should be particularly suited for aviation purposes as sticking or burning of the poppet valves is entirely eliminated, due to the alternate cooling of the valves 6 during the intake strokes. The valve operating mechanism is materially simplified as the valve stems are disposed at right angles to theidrive shaft and are, directly actuated thereby through means of the cam 8.- The rotary valve employed is also important as it functions in cooperation with the poppet valves first to direct and admit the incoming combustible mixture, and secondly in removingor carrying away the exhaust or burnt gases.

A rotary valve such as here shown need not be very tightly packed, as leakage of exhaust gases is of no material importance. Leakage of incoming gases cannot vtake place as the passage15 is continuously subjected to suction. That is, considerable wear, as far as the rotary valve is concerned, may take place without impairing the functioning of the engine. Such wear might possibly admit a certain amount of atmospheric air between the elbow shaped ports 4' and the inlet port 15 but such leakage or air admission would readily be compensated for by enriching the carbureter. Leakage of exhaust gases would be of no importance as they are finally dirooted. to the atmosphere in any case. p

The most important feature of all is the provision of a valve mechanism which is very simple and which is reliable and dependable under all conditions of load and speed, this being mainly due to the fact that the poppet valves are directly actuated by the cam on the drive shaft and because they alternately function as inlet and exhaust valves, thereby preventing overheating, burning and sticking of the individual valves;

While certain features of the present invention are more or less specifically described, I wish it understood that various changes may be resorted to within the scope of the appended claim, similarly, that the materials and finishes of the several parts employed may be such as the manufacturer may decide, or varying conditions or uses may demand.

Having thus described m invention, what I claim and desire to secure y Letters Patent 1s:

In an engine of the character described, a main drive shaft, a plurality of cylinders surrounding the shaft with their longitudinal axis parallel to the shaft, a head on each cylinder and each head having a single port formed therein functioning as an inlet and exhaust port, a valve supporting head centrally disposed between the cylinder heads and secured to said heads, said valve supporting head having a plurality of ports formed therein one for each cylinder head port and communicating therewith, a plurality of puppet valves carried by the valve supporting head and extending through said last named ports and adapted to open and close communication between said ports and the cylinder head ports, a central bearing formed in the valve supporting head to support one end of the main drive shaft, said end of the shaft being hollow and connected with a carburetor, a rotary valve mounted in the valve supporting head, said rotary valve havingan inlet port formed therein, one end of said port being in constant communication with V the hollow shaft and the carburetor and the other end adapted to successively register with the cylinder head ports, an exhaust manifold, said rotary valve also having an exhaust port formed therein one end being in constant communication with the exhaust manifold and the other end adapted to suecessively register with the cylinder head ports, a piston in each cylinder, means whereby reciprocal movement of the piston is transmitted to rotate the main drive shaft at cam shaft speed, a driving connection formed between the main drive shaft and rotary valve whereby the rotary valve will rotate at cam shaft speed, and a single cam mounted on the main drive shaft whereby the puppet valves are successively actuated, said cam being so shaped as to retain each puppet valve open during the exhaust and intake cycle of each cylinder, and said rotary valve being so timed as to bring the exhaust and inlet port formed therein into register with the puppet valves when they are open.

PIETRO ARRIGHI.

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