US1172324A - Two-cycle internal-combustion engine. - Google Patents

Description

, D. M. TUTTLE.

TWO-CYCLE INTERNAL COMBUSTION ENGINE.

APPLICATION FILED NOV. 27.19I2. LI'FQQBQQ, Patented Feb. 22, 1916.

4 $HEETSSHEET I.

D. M. TUTTLE.

TWO-CYCLE INTERNAL COMBUSTION ENGINE.

APPLICATION FILED NOV-27.1912. 1,172,324, Patented Feb. 22,1916.

4' SHEETS-SHEET 2.

fiiiorncy D. M. TUTTLE.

TWO-CYCLE INTERNAL COMBUSTION ENGINE.

APPLICATION FILED NOV.Z7,19I2.

Patented Feb. 22, 1916.

4 SHEETSSHEET 3.

Jnv n r Wiines e5 D. M. TUTTLE.

TWO-CYCLE INTERNAL comsusnow ENGINE. APPLICATION FILED NOV. 27. I912. 1 172 324. Patented Feb. 22,1916.

4 SHEETSSHEET 4- rrnn erm ne PATENT GFFIQQ DANIEL M. TUTTLE, OF CANASTOTA, NEW YORK, ASSIGNOR TO STELLA S. TUTTLE, OF CANASTOTA, NEW YORK.

TWO-CYCLE INTERNAL-COMBUSTION ENGINE.

Application filed November 27, 1912. Serial No. 733,870.

To (ZZZ whom it may concern:

Be it known that I, DANIEL M. TUTTLE, of Canastota. in the county of Madison. in the State of New York, have invented new and useful Improvements in Two-Cycle Internal- (lombustion Engines, of which the following, taken in connection with the accompanying drawings, is a full, clear, and exact description.

This invention relates to certain improvements in two-cycle internal combustion engines of the class set forth in my pending applications Nos. (360,834 filed November 17, 1911. and 6 54.760 filed August 18, 1911, in which the cylinders are provided with valvecontrolled intake and inlet ports and pistoncontrolled exhaust ports, said cylinders being arranged in pairs and provided with a constantly open passage connecting the valve chambers of the intake valves with those of the inlet valves for the purpose of reserving a quantity of the explosive mixture under pressure at both of the inlet valves, such pressure being sufficient to hold the inlet valve of each cylinder open some time after the exhaust port of such cylinder has been closed by the compression stroke of the corresponding piston.

This constantly open passage serves to materially increase the power eiiiciency of the engine, but I have discovered that. even under these favorable conditions. the high degree of pressure exerted upon the inlet valve when it opens, allows the infiowing charge to enter the firing chamber with such force as to drive it rapidly toward the bottom of said chamber and to the exhaust port and thereby produce an undesirable mixture with the burned gases which incidentally lowers the possible power efficiency of the engine.

The main object therefore is to reduce this excessive initial pressure and to render such reduced pressure more equal and constant at the inlet so that when the inlet valve is open the new charge will not enter with such rapidity and force as to produce an objectionable mixture with the spent gases or escape at the exhaust but on the contrary will collect in a more compact mass in the head of the firing chamber and more effectively expel the burned gases while the exhaust is open thereby obtaining a more powerful mixture and assuring a more posi- Specification of Letters Patent.

Patented Feb. 22, 1916..

give ignition without skipping or missing Another object is to increase the advantages of the reduced and equalized pressure by baffling the direct passage of the inflowing charge to the exhaust and thereby increasing its compactness and ability to expel the spent gases at the proper time without mixing therewith.

A further object is to obtain a greater power efficiency in multi-cylinder engines by arranging such cylinders in pairs and connecting their intake ports and inlet ports in such manner as to maintain a constant pressure of the inflowing mixture upon the inlet valves tending to hold such valves open after the exhaust ports of each cylinder are closed by their respective pistons, thereby permitting a higher degree of compression ofa greater quantity of the explosive mixture in the firingchamber than would be possible if the inlet valves were closed simultaneously with or before the closing of the exhaust ports as usual in two-cycle engines.

()ther objects-and uses will be brought out in the following description.

In the drawings, Figure 1 is a side elevation, partly in section, of a two-cycle fourcylinder engine embodying various features of my invention. Figs. 2 and 3 are transverse vertical sectional views of the same engine taken respectively on lines 22 and 3-43. Fig. 1. Fig. 4 is a longitudinal vertical sectional view of a two-cylinder engine of the same type showing a modified ar-' rangement of the connecting'passage between the valve chambers for the intake and inlet valves. Figs. 5 and 6 are transverse vertical sectional views taken respectively on lines 5-5 and 66, Fig. 4. Fig. 7 is a detail sectional view of the upper portion of one of the cylinders showing a slightly modified form of retarding flange for the infiowing mixture. Fig. 8 is a longitudinal vertical sectional view of a modified form of 1)ressure-equalizing chamber having branches connected directly to the valve chambers for the intake valves. F ig..9 is a transverse vertical sectional view through the pressureequalizers shown in Fig. 8.

The engine shown in Figs. 1. '2 and 3 comprises a series of four cylinders, 1, -2-. 3- and 4, arranged side by side in pairs and provided with pistons 5 which are connected by suitable pitmen -6 to a crank shaft -7, the crank arms of the shaft being arranged on the quarter turn relatively to each other. That is, the crank arms corresponding to each pair of cylinders are diametrically 0pposite, so that when the pistons of one pair of cylinders are at the limit of their strokes at opposite ends thereof, the pistons of the other pair of cylinders will be on the half stroke but moving in opposite directions. The cylinders are substantially identical in form and size and each is provided with a firing chamber 8 and a coaxial compression chamber 9 of greater cross sectional area than the firing chamber,.while each of the pistons 5 comprises a main body 10 of substantially the same diameter as and movable within the firing chamber 8 and a coaxial compression head -11 of substantially the same diameter as and movable within the compression chamber 9. The object of these differential sized portions of the cylinder and piston is to produce a higher degree of initial compression of the mixture admitted to the compression chamber preparatory to expulsion into the firing chambers. These features, however, are clearly brought out in my pending applications above referred to and, therefore, need not be more fully described in this case. Each cylinder is provided with an intake port -12, an inlet port 13 and an exhaust port 14.'.

The intake port -12, which is connected in the manner hereinafter described to a suitable carbureter (not shown) communicates with the inner end of the compression chamber 9 and is controlled in this instance, by a rotary valve 15 external to the cylinder.

The inlet ports 13 which are preferably located in the heads of the cylinders and communicate with the firing chambers, are controlled by puppet valves -16 and, as shown more clearly in Figs. 2 and 3, are in constant communication with the valve chambers for the valves 15 through suitable conduits or passages 17.

The exhaust ports -14- of the several cylinders are located,- as shown, near the outer ends of the firing chambers and are controlled by their respective pistons 10-, said exhaust ports being connected by a suitable manifold 18.

The valves 15 for the several intake ports 12 are coaxial with and connected for simultaneous rotation by any suitable driving mechanism (not shown but capable of synchronizing the movement of said valves with that of their respective pistons.)

Each valve chamber for the valve 15- is provided with a series of, in this instance three, ports, .-19, -20 and 21.

r which are connected respectively to the carbureter (not shown), the intake port l2 and the corresponding conduit 17 as shown more clearly in Fig.

Each of the valves 15 is provided with diametrically opposite transverse recesses 22- and 23 adapted to alternately and successively connect the port 20 with the ports 19- and 2l, said valve being so timed as to connect the ports 19 and .-20 and thereby establish communication between the carbureter and intake port during the out-stroke of the piston and then to connect the ports 20- and 2l during the compression stroke of such piston so as to establish communication between the intake port and the inlet ports of'both cylinders through the passage or conduit 17- tending to open the valves 16 against the action of suitable retard- 111g springs 24. by which said valves are automatically closed. At about the time or just after the piston has reached'the limit of its compression stroke, during which the explosive charge in the firing chamber is under a high degree of compression greater than that tending to open the valve, thereby holding said valve closed during the eX- plosion, the valve 15 will have been moved a quarter turn to close the ports V19 and -21- and thereby cut off communication between the firing chamber and compression chamber and also between the carbureter and compression chamber. As the piston begins and during its outward stroke, the valve 15 will have shifted rotarily to connect the ports 19 and -20, thereby causing the mixture to be drawn by suction of the piston head ll from the carbureter into the compression chamber -9, it being understood that during this operation communication between the ports 20 and 2l is cut off. This induction of the mixture will continue until and a short time after the piston reaches the limit of its-suction stroke whereupon the operation of the valve, as previously described, will be repeated. As the piston reaches the limit of its outward stroke, it will uncover and permit the discharge of the spent gases through the exhaust port 14 and this expulsion of the spent gases from the firing chamber will be augmented by the inflowing mixture, which, it will be remembered, was under compression at the inlet port sufficient to open the valve by reason of the fact that the pressure resistance to such opening gradually reduces as the piston reaches the end of its out-stroke and particularly when the exhaust port is opened.

It is now evident that the pressure of the, mixture tending to open the inlet valves will be suificient to hold either of said valves open during a considerable part of the compression stroke of the corresponding piston after the latter has closed its exhaust port and until the counteracting pressure of the compressed charge is equal to or exceeds that of the inflowing mixture whereupon such valve will be closed and will remain closed during the firing of the charge and until the pressure in the firing charmber is reduced by the out-stroke of the piston to a degree less than that of the inflowing mixture which will take place as soon as or beforethe piston begins to uncover the exhaust port at which time the valve will be again opened to admit a fresh charge to the firing chamber.

The operation of each piston is substantially the same as that ust described owing to the fact that the conduits -17 communicate with all of the valve chambers of the intake valves and also with all of the valve chambers of the inlet valves.

In order to maintain a more uniform pressure at the inlet, I have provided the connection between. the intake ports and inlet ports with an auxiliary pressureequalizing chamber -26 which may also be termed a pressure reservoir in which a portion, at least, of the highly compressed mixture is temporarily trapped, thus reducing the initial pressure and keeping the reduced pressure more constant and in a compact mass inthe head of the firing chamber while the inlet valve is open.

Owing to the fact that the mixture is introduced into the firing chambers of the cylinders under considerable pressure while the pistons are approaching the limits of their outward strokes, there is liability of such mixture taking a direct course through the firing chamber to the exhaust and not thoroughly scavenging the cylinder from the spent gases when the exhaust is opened.

In order to more thoroughly expel the spent gases from the firing chamber, I have provided each cylinder with an inwardly projecting flange -30 having a concaved deflecting surface facing the inlet port so that, when the inlet valve is opened, the influx of the mixture is diverted into the pocket formed by the concaved surface and is thereby deflected toward the center of the firing chamber to form a cushion covering the entire area of the interior of the cylinder adjacent the inlet traveling toward the exhaust and thereby more effectively expelling the spent gases. This flange may extend only part way across the cylinder, as shown more clearly in Figs. 2 and 5, in which case it will be on the same side as the exhaust port or it may extend entirely around the interior of the cylinder thus forming anannular flange as shown in Fig. 7. In either of these forms, however, the flange serves to prevent direct passage of the mixture along the sides of the cylinder to the exhaust by concentrating such mixture at the center engines are substantially the same as for the .chambers for the intake valves with the inlet ports is located between the cylinders instead of at one side thereof. The valves and valve chambers for these two-cylinder 8O four-cylinder engines except that they have but two in-take valves instead of four, but the conduits leading from the intake valve chambers to the inlet ports are provided with a pressure-equalizing chamber -26' for the same purpose as the chamber 26 previously described, said pressure-equalizing chambers being located at one side of the main passage between the intake and inlet ports so as to avoid condensation and consequent imperfect mixture.

In Fig. 8 I have shown a slightly modifiedform of pressure-equalizing chamber 31 having branches 32 connected directly to the valve chambers as 33 for the intake valves instead of connecting such equalizing chamber to the conduit 17 as shown in Figs. 1, 2 and 3, the conduits -17- being kept separate at their crossings by a partition between them as shown more clearly in Fig. 2 although both conduits communicate at this point with the equalizing chamber 26.

In Fig. 2, I have shown the cylinder as provided with an auxiliary exhaust or pressure relief port 14' located about midway of the compression stroke of the piston between the main exhaust port 14- and baffle plate 30. at the same side of the cylinder as the main exhaust port and connected by a conduit -18 with the manifold exhaust pipe 18 so as to discharge thereinto, said conduit being provided with a rotary valve -40 which is normally closed when the engine is running under full load or high speed but is adapted to be opened at will by any suitable operating mechanism when the engine is running light or idle to allow partial exhaust of the spent gases before the main exhaust is opened and 1 thereby reducingthe vibration of the engine and also to induce the noise incidental to the use of a single exhaust port as 14..

Another important feature of my invention consists in the intersecting cross connections 1 7- connecting opposite pairs of cylinders, each connection serving as a means of communication between the intake ports of one pair of cylinders with the inlet ports of the opposite pair so that the compression stroke of the cylinder of either pair will force a charge of the. explosive mixture into the firing chamber of one of the cylinders of the other pair and will also force a part of such charge into the firing chamber of the first named cylinder during a part of its compression stroke after its exhaust port is closed or until the pressures at opposite sides of the inlet valve of such cylinder is equal, it being understood that a quantity of the explosive mixture is always maintained under pressure at all of the inlet valves and that, while the piston of one of the cylinders is passing through its entire compression stroke, the inlet valves of the other cylinder will be successively opened by the pressure of the mixture produced by that piston, this operation being repeated during the com-- pression stroke of each of the pistons.

What I claim is:

1. In a two-cycle internal combustion engine, a pair of cylinders having valvecontrolled intake and inlet ports and pistoncontrolled exhaust ports, and a constantly open passage connecting the 'valve chambers of both the intake and inlet valves, valves for said intake and inlet ports and a pressure equalizing chamber in direct and constant communication with said passage, said valve for the-inlet port being spring closed and opened only by gas pressure in the passage.

2. A two-cycle internal combustion engine having its cylinder provided with constantly connected intake and inlet valve-chambers and a piston-controlled exhaust port, valves in said chambers, and a flange on the interior of the cylinder having a concave side facing the inlet to temporarily pocket a portion of the infiowing mixture and prevent its direct flow from the inlet to the exhaust port, said inlet valve being opened only by the gas pressure in said passage.

3. A two-cycle internal combustion engine comprising separate pairs of cylinders, each having an intake port, an inlet port, an exhaust port, and a piston controlling the exhaust port, synchronized valves for the intake ports and conduits each leading from the valve chamber of one pair of cylinders to the inlet port of the other pair of cylinders, said inlet ports having self-closing valves opened only by the gas pressure in the conduits leading thereto.

4. A two-cycle internal combustion engine comprising separate pairs of cylinders, each having an intake port, an inlet port, an exhaust port and a piston controlling the ex- I haust port, synchronized" valves for the intake ports, conduits each leading from the valve chamber of one pair of cylinders to the inlet port of the other pair of cylinders, and an equalizing chamber communicating with conduits, said inlet ports having separate self-closing valves opened only by the pressure of fuel in the conduit leading thereto.

5. In a two-cycle internal combustion engine, a cylinder having an inlet port and an exhaust port and a piston controlling the exhaust port, said cylinder having an auxiliary port with sufficient pressure to hold the inlet valve open during a portion of the compression stroke of the piston after the exhaust port is closed by said piston.

6. In a two-cycle internal combustion engine, a cylinder having an inlet port in its head end and an exhaust port in one side, a piston movable in the cylinder and controlling the exhaust port said cylinder having an auxiliary exhaust passage between the exhaust port and inlet port and in the same side of the cylinder as the exhaust port, and a valve in said passage, said inlet port having a self-closing valve in combination with means for introducing the fuel into the inlet port with sufiicient pressure to hold the inlet valve open during a portion of the compression stroke of the piston after the latter has closed the exhaust port.

7. In a two-cycle internal combustion engine, a cylinder having an inlet port in its head end and an exhaust port in one side, a piston movable in the cylinder and controlling the exhaust port, a baflie plate in a di -rect line between the inlet port and exhaust port to prevent the direct passage of the inflowing mixture to the exhaust port, said cylinder having an auxiliary exhaust passage between the .exhaust port and baffle plate, and a valve in said passage, said inlet port having a self-closing valve in combination with means for introducing the fuel into the inlet port with suflicient pressure to'open the inlet valve during a portion of the compression stroke of the piston after the exhaust port is closed.

8. In a two-cycle internal combustion engine, the combination of a cylinder having a firing chamber and a relatively larger fuel compression chamber, said chambers having respectively a fuel intake port and a fuel 'inlet port, the firing chamber being provided with an exhaust port and an auxiliary exhaust passage between the exhaust port and the head of the cylinder, a conduit connecting the intake port of the compression chamber with the fuel inlet port of the firing chamber, a valve controlling the passage of fuel through said conduit, connected pistons moving in said chambers, a valve for the exhaust passage, and a separate self-closing valve for the inlet port opened only by the pressure of the fuel passing through said conduit.

9, In a two-cycle internal combustion engine, the combination of a cylinder having a chamber, a valve controlling the passage of fuel through said conduit, connected pistons moving in said chambers, a valve for the exhaust passage, and a separate self-closing Copies of this patent may be obtained for five cents each, by addressing the valve for the inlet port opened only by the pressure of the fuel passing through said 15- con'duit, said conduit having a pressureequalizing chamber into which a portion of the fuel under pressure is forced when the valve for the intake port is opened.

In witness whereof I have hereunto set 20 my hand this 9th day of November, 1912.

DANIEL M. TUTTLE.

Witnesses:

H. E. CHASE, EVA E. GREENLEAF.

Commissioner of Patents,

Washington D. G.

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