US2554645A

US2554645A - Two-stroke internal-combustion engine

Info

Publication number: US2554645A
Application number: US124524A
Authority: US
Inventors: Serste Jacques Egide; Teplow Jacqueline Serste; Serste Paul; Serste Pierre
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-10-25
Filing date: 1949-10-31
Publication date: 1951-05-29
Anticipated expiration: 1968-05-29

Description

May 29 1951 Y J. E. sERs'rE ETAL 2,554,645

TWO-STROKE INTERNAL-COMBUSTION' ENGINE i Filed oor. s1, 1949 4 shees-sheet 1 A A f, A t {Inf/0 'f ifi/1111411111111,

AT EY.

J. E. sERs'r ET Al.

Two-STROKE 1NTERNALC0MBUSTI0N ENGINE May 29, 1951 i Filed Oct. 5l, 1949 4 Sheets-Sheet 2 u .f A l I Q anniv/J m. ...x A

AT TORNEY.

.L A T E T S R E S E lum TWO-STROKE INTERNAL-COMBUSTION ENGINE 4 Sheets-'Sheet 5 Filed 001.. 31, 1949 AT1-oww 29, 1951 J. E. SERS-rE: ET AL 2,554,645

TWO-STROKE INTERNAL'-CONIBUSTIOIl ENGINE Filed Oct. 3l, 1949 4 Sheets-Sheet 4 Patented May 29, 1951 TWO-STROKE INTERNAL-COMBUSTION ENGINE Jacques Egde Serst, Jacqueline Serst Teplow, Paul Serst, and Pierre Sei-st, Forest-Brussels,

Belgium Application October 31, 1949, SerialNo. 124,524 In the Netherlands October 25, 1948 19 Claims. 1

Our invention has for its object internal combustion and the like engines of the two stroke type, the scavenging and the movements of the load being executed under equicurrent conditions throughout the cylinder.

In two stroke engines of standard type, the illling of the cylinders is obtained by loading them through a stream of fresh gases blown into same for exhausting the burnt gases. It is thus necessary to incorporate a pumping system so as to suck in the fresh gases and to deliver them into the cylinder inside which they unavoidably come into contact with the residual gases that have already expanded through their laminating passage inside the exhaust ports under delivery pressure while in close contact with the fresh gases. Said contact between two gases, even of a very short duration, can but stir the masses with one another, which leads on one hand to losses of fresh gases exhausted with the burnt gases and on the other hand to a sort of poisoning of the load through the burnt gases'admixed therewith.

The suction and exhaust means provided for such conventional engines do not allow contemplating any other solution to the problem.

O ur invention has for its object to bring a deep modication to the standard technique, the movements of the load being assured through an extremely rapid opening and closing of the large sized suction and exhaust ports so as to provide an immediate exhaust of the residuary gases at one end of the cylinder under the action of their spontaneous expansion. By reas-on of their dynamic energy the mass of exhausted gases sucks in energetically the gases forming the load through the suction ports that have been uncovered in the meantime at the other end of the cylinder. The rapid closing of the exhaust ports stops then the passage of this current of gases arriving at full speed and causes the latter to settle over a height corresponding to the volume and speed of said current while the closing of the suction ports opposes the retrogression vlof the,

gases and produces an excess pressure inside the cylinder. The overload increases by reason of the acceleration of the engine speed and may reach considerable values.

Whereas in engines of the fuel injectiontype, the adjustment .allows an excess passageof air,

the case is not the same in engines where the explosive load is submitted to a preliminary stirring and cannot be lost. In this latter case, the adjustment may loe-executed in a manner such that the burnt gases and the load move with an intermediary zone of depression between them that i's cut in vacuo through a closing of the exhaust which removes the possibility of a loss of rich gases without changing the conditions of admission and delivery for the engine.

We have shown by way of example and by no means in a binding sense, various embodiments of our invention. In said drawings:

Fig..l is a sectional view of yan engine incorporating the principle of our invention.

Fig, 2 illustrates a modication thereof.

Fig. 3 shows on `a larger scale and cross sectionally the upper part of an engine with an overhead valve gear.

Fig. 4 is a graph showing the transmission-gear for every 10 of the revolution of the eccentric.

Fig. 5 is a graph giving out the movements of the driving piston for every 10 of said revolution.

Fig. 6 is a diagram corresponding to the graphs of Figs. 4 and 5 for two diiierent adjustments.

Fig. 7 illustrates a set of control links operating in the same plane.

Figs. 8 and 9 illustrate modifications of this arrangement of control links.

Fig. 10 is an elevational view of a cylinder sleeve with two slide valves controlled by a compensation bar.

Fig. 11 is a diagrammatic showing of the control means for a radial engine.

Figs. 12 and 13 are diagrammatic illustrations in side and elevational views of the control mechanism driven by a crankshaft provided with two sleeves and with further links.

Fig. 14 is an elevational view of a cam-operated control system.

In the embodiment illustrated in Fig. 1 the engine includes primarily-an engine unit I `with its crankcase 2, its water jacket 3,v its exhaust pipe 4its admission pipe 5 and its head 6 engaging the cylinder down to the upper level of the upper ports provided for the passage of the gases.

The crankshaft 'l and its connecting rod 8 are operatively( connected with the piston 9 slidably carried inside Vthe stationary sleeve I0. Said sleeve is provided with upper ports II and with lower ports I2 which latter are in register with a point occupied by a point of the head of the driving piston just above the lower dead center of the piston stroke.

The sleeve I is enclosed by the slide valve I3 the ports Ill and I in which are adapted to move respectively over the ports EI and over the ports I2 in the sleeve under the action of a mechanism oprated by an eccentric I6 driven by the engine and including a link connection I'l--I between said eccentric and the slide valve, said link connection pivoting round the spindle axist I9. The transmission of the sliding movement to the slide valve I3 for covering and uncovering the ports II and I2 is obtained through cooperation with the link 2t controlling said slide valve in either direction, the direction of the movement of the slide valve being always opposed to that of the driving piston.

The rst slide valve I3 is enclosed inside a further slide valve 2| provided with ports 22 crossing the ports I for registering at a predetermined moment of their movement with the ports II and simultaneously with the ports I4, the movement of said slide valve 2| being controlled by a bar 23 connected with both slide valves I3 and 2| for providing their movements in opposite directions. These opposed movements are obtained through the

rods

24 and 25 while the head of the piston 9 moves in a direction opposed to that of the ports I5 in the slide valve I3 so as to uncover the admission ports I2 in cooperation with the latter ports.

This arrangement of two slide valves moving simultaneously in opposite directions provides openings of the same size as a single slide valve but it produces their covering and uncovering in half the time required with a single slide valve operating with equal lengths of stroke in either direction, while allowing the possibility of providing the desired shifting for the timing and duration of exhaust and admission.

Referring to Fig. 2, it is apparent that it is similar to Fig l with the difference that the slide valves I3 and 2| are housed inside the engine cylinder, the slide valve I3 taking the place of the cylinder lining Ii) and serving as a bearing for the driving piston 9 without anything being changed in the closing operation performed by it. Furthermore the slide valve 2| is controlled by a projection controlled in its turn by a rod 21 while the connections disclosed hereinabove as provided between the slide valves I3 and 2l are cut out as illustrated.

As illustrated in Fig. 3, the timing gear is carried in overhead relationship with the engine so as to locate next to it, the compact arrangement of Fig. l including the eccentric IB, a pivoting link system I'I-I8 connected with the stationary\pivot i9 and the link 25 acting on the compensating bar 23 for transmitting the movement to the slide valve 2l and to the slide valve I3 through the agency of the

corresponding rods

25 and 24.

The operation of the three embodiments will appear in the graphs of Figs. 4 and 5 and in diagram of Fig. 6. Thus Fig. 4 shows for each 10 of the revolution of the eccentric IB the location of the mechanical system and chiey of the compensating bar provided for the control of the slide valves.

Fig. 5 illustrates for every 10 of the movement the location of the driving piston for the portion of the stroke thereof corresponding to the covering and uncovering of the lower ports.

Fig. 6 is a diagram illustrating clearly the practical consequences of the graphs of Figs. 4 and 5 with two different timings of the opening of the exhaust through the upper ports, and of the admission through the lower ports; the curves show the movements in opposite directions of the cooperating moving ports.

The timing of the admission through the lower ports corresponds to the drawing in solid lines while the other timing with admission through the upper ports and exhaust through the lower ports corresponds to the drawing in dot and dash lines. The reference numbers given are the same as those of the ports in the stationary sleeve I oi Fig. l while the hatched parts IIL-I23 correspond to the capacities of the exhaust and. the hatched parts E22 and I I3 correspond to the capacities of the admission, the engine being supposed to have its exhaust built in overhead relationship.

Within the scope of the invention, it is possible for instance to cut out the slide valve 2I and the transmission means controlling it in any of Figs. 1, 2 and 3 so as to provide a single covering means for the upper ports while the lower ports remain controlled by double covering means of which one is actually formed by the moving piston.

it is possible also for the driving piston to provide alone for the control of the lower ports while one or two covering members or slide valves control the upper ports.

rEhese various combinations are applicable with advantages that are similar to those provided by the embodiments illustrated, chiefly in the case of engines with small or average sized cylinder capacities in accordance with the cycle of operations disclosed by the diagrams.

Fig. '7 illustrates on a larger scale and in plan view a system of links of the type illustrated in Fig. l together with their controlling and connecting means operating in a same plane.

Figs. 8 and 9 illustrate a combination of the f system of links and control means operating in several planes for actuating two slide valves moving in opposite directions as in the case of Figs. 2 and 3.

Fig. l0 shows a cylinder sleeve I D provided with two slide valves I3 and 2| attached respectively at I3 and at 2|. Said points I3 and 2l are connect d through rods 2@ and 25 to two projections deilning a compensator bar 23, which projections are secured to the rocking shaft I9 controlled by a set of links not illustrated.

In Fig. ll, we have illustrated a control system for an engine the cylinders of which are arranged in radial relationship while the different slide valves are actuated by a common eccentric I6 secured to a shaft 3? forming an extension of the crankshaft, the link system of each cylinder being pivotally secured to a ring 3i controlled by the eccentric i6 and held in a stable position through the eccentric 53 connected with the projection :i2 on said ring 3l. It is thus apparent from inspection of Fig. l1 how the position oi the links lies for the seven stages of a cycle extending a little over 51 of the revolution of the crankshaft.

This arrangement is applicable as well of course to all engines with a radial sectional arrangement.

A control mechanism for the slide valve or valves includes further members with the object either of shifting the moments of acceleration or assailant of -adjusting the magnitudes governing the 'strokes and accelerations or else of obtaining any other modication in accordance with the re- ,quirementsof the cycle of operation or the constitution of the engine. This is shown in Figs. .l2 and 13 where the crankshaft is provided with asecond crank of eccentric-33 acting on the connecting rods Sil, 35 of which the latter is inserted between'the connection with the links Il, i8 and the connecting rod Z leading to the slide valves.

Turning to Fig. 14 said figures show a camoperated control mechanism ensuring a positive drive in both directions.

To the shaft 36 are secured in different planes cams 3l and 38 ci which the -former engages the roller Se while the second cam engages the roller lill. The two rollers are rotatably carried by the compensator member' 23 through 'the agency of a rocking shaft 35 controlling the slide valves I3 and 2| knot illustrated through the connections Vprovided by the rods 2d and 25.

During the period during which the rollers 39 and dtlfare in contact with parts of the cams .3l and 33 co-a-Xial with the shaft 35, the movement of the slide valves is zero, said movement being started suddenly through eccentric portions of said cams. The whole cycle of operation of the cams is executed without either of them moving theoretically out of contact with reference to its rollers. covering of the ports similar to that appearing in Fig. 6.

From the preceding disclosure, it is apparent that the port covering member operating Asingly controls the corresponding ports at a speed that may be suiiicient lfor operation with either rate of operation of the ports, while retaining all the advantages described Vfor certain categories of vengines-whereas for other categories, it is necessary to resort to double covering members because they may double the speed of covering and of uncovering the passages for the gases.

Without unduly widening the scope of the invention as defined in Vaccompanying claims,.it is possible to incorporate the above arrangement of y slide valves and of a piston to double acting engines or the like, both for exhaust .and for admission and the shifting of the timing may be obtained without any shifting of the relationship between the crankp-ins of the two driving crankshafts to be considered; the movement of the closing slide valves mai7 be operated axially of the cylinder or else itis possible to make them assume a tacking movement with reference to said cylinder.

This arrangement may'lead to an unl The arrangement disclosed is also applicable for other arrangements of the cylinders with .an engine of radial or radial section type, also `with engines of the double or multiple actingtype or else having moving cylinders arranged in square or the like formation. The connections between the control means and the slide valves may `be performed also through the head of yeach cylinder; any further arrangements of links and transmission means and relays may be inserted between the control means and the slide valves; the slide valves may be constituted by interconnected sections or else these sections may be controlled by a crankshaft provided with a plurality Aof cranks or by a plurality of crankshafts; the control and transmission means may be secured to a number of stationary points and in brief any combination may be made between the elements described and disclosed.

Obviously, our invention has been describedas 6 illustrated by way of a .mere indication and `by no means in a limiting ysense and numerous modications may be brought to the details thereof withoutl unduly Widening thereby the scope offtl'ie invention as defined in accompanying claims.

What We claim is:

1. In a two stroke internal combustionand the like engine, the combination of a cylinder provided at each end with two series of ports adapted respectively to serve as admission portsand asexhaust ports, 'the upper series of ports being provided .at the upper end of the cylinder and the lower series opening substantially at the lower end of the combustion chamber in the cylinder, a driving piston adapted to reciprocate inside the cylinder between an upper dead point and a lower dead point substantially in register with the lower series oi ports, a slide valve slidably engaging onel of the surfaces of the cylinder land provided with a series of ports adapted to register with the upper series of ports in the cylinder, a linlrwork connected with the slide Valve for producing a sliding movement of the latter over'the cooperating surface of the cylinder, an eccentrically operating member controlling the link work to constrain the slide valve to operate cyclically, the cyclic operation of the valve including a long period of very small oscillations providing for the covering of the upper series of ports in the cylinder and then a very highly accelerated movement vfor uncovering and then covering again said upper seriesof ports in the cylinder while the valve moves at high speed and produces thus an opening of the upper ports with a large cross-sectional passage during a very short time, the cycle terminating with the return into the port covering position, the driving' piston being adapted to cover and uncover the lower series of ports in the cylinder a lag being provided between the uncovering of the upper series of ports and that of the lower series of ports in the cylinder.

2. In a two stroke internal combustion and the `like engine, the combination of a cylinder provided at each end with two series of ports adapted respectively to serve as admission ports and as exhaust ports, the upper series of ports being provided at the upper end of the cylinder and the lower series opening substantially at the lower end of the combustion chamber in the cylinder, a driving piston adapted to reciprocate inside the cylinder between an upper dead point and a lower dead point substantially in register with the 10W- er series of ports, a. slide valve provided with two series of ports adapted to register respectively `with the upper and with the lower series of ports in the cylinder, a linkwork connected with the slide valve for producing a sliding movement of the latter over the cooperating surface of the cylinder, an eccentrically operating member con'- trolling the linkwork to constrain the slide valve to operate cyclically, the cyclic operation of the valve including a long period of very small oscillations providing for -the covering `of the upper and lower series of ports in the cylinder and then a very highly acceleratedmovement for uncovering Yand then covering again said upper and lower series of ports in the cylinder while the valve moves at a high speed and produces thus an opening of the upper porls with a large crosssectional passage during a very short time, vthe cycleterminating with the return into the port covering position, the driving'piston cooperating with the lower series of ports in the slide valve for uncovering and covering at a high speed said lower series of ports in the cylinder through a movement that is simultaneous with and in the opposite direction with reference to that of the slide valve in front of said lower series of' ports, a lag being provided between the uncovering of the upper series of ports and that of the lower series of ports in the cylinder.

3. In a two stroke internal combustion and the like engine, the combination of a cylinder provided at each end with two series of .ports adapted respectively to serve as admission ports and as exhaust ports, the upper series of ports being provided at the upper end of the cylinder .and the `lower series opening substantially at the lower end of the combustion chamber in the cylinder, a driving piston adapted to reciprocate inside the cylinder between an upper dead point and a lower dead point substantially in register with the lower series of ports, two slide valves provided each with a series of ports adapted to register with the upper series of ports of the cylinder, said slide valves being arranged to either side of the cylinder wall and being adapted to move simultaneously and in opposite directions in register with the upper ports in the cylinder for covering and uncovering same through their cooperation, a linkage connected with at least one slide valve, an eccentric member positively controlling said linkage, a rocking lever operatively connecting the two slide valves together, said arrangement of the linkage, eccentric and rocking lever being adapted to constrain the slide valves to move in opposite directions when closing the upper series of ports in the cylinder and to operate cyclically, the cycle of operation including a long period of short oscillations while the .slide valve closes the upper series of ports in the cylinder, after which the slide valves assume a high acceleration for uncovering and then covering again said upper series of ports in the cylinder while the valves move at high speed and produce thus an opening of the upper ports with a large cross-sectional passage during a very short time, the cycle terminating with the return into the port covering position, the driving piston being adapted to cover and uncover the lower series of ports in the cylinder, a lag being provided between the uncovering of the upper series of ports and that of the lower series of ports in the cylinder.

4. In a two stroke internal combustion and the like engine, the combination of a cylinder provided at each end with two series of ports adapted respectively to serve as admission ports and as exhaust ports, the upper series of ports being provided at the upper end of the cylinder and the lower series opening substantially at the lower end of the combustion chamber in the cylinder, a driving piston adapted to reciprocate inside the cylinder between an upper dead point and a lower dead point substantially in register with the lower series of ports, two slide Valves provided each with a series of ports adapted to register with the upper series of ports of the cylinder, said slide valves lying respectively in contact with one surface of the cylinder and with the surface of the iirst slide valve that is not in contact with the cylinder wall and being adapted to move simultaneously and in opposite directions in register with the upper ports in the cylinder for covering and uncovering same through their cooperation, a linkage connected with both slide valves, an .eccentric controlling said linkage for constraining the slide valves to move in opposite directions when closing the upper series of ports in the cylinder and to operate cyclically, the cycle of operation including a long period of short oscillations while the slide valve closes the upper series of ports in the cylinder, after which the slide valves assume a high acceleration for uncovering and then covering again said upper series of ports in the cylinder while the valve moves at high speed and produces thus an opening of the upper ports with a large crosssectional passage during a very short time, the cycle terminating with the return into the port covering position, the driving piston being adapted to cover and uncover the lower series of ports in the cylinder, a lag being provided between the uncovering of the upper series of ports and that of the lower series of ports in the cylinder.

5. In a two stroke internal combustion and the like engine, the combination of a cylinder providedv at each end with two series of ports adapted respectively to serve as admission ports and as exhaust ports, the upper series of ports being provided at the upper end of the cylinder and the lower series opening substantially at the lower end of the combustion chamber in the cylinder, a driving piston adapted to reciprocate inside the cylinder between an upper dead point and a lower dead point substantially in register with the lower series of ports, two slide valves of which one is provided with two series of ports adapted to register respectively with the upper ports of the cylinder and with the lower series of ports while the other slide valve is provided with a single series of ports adapted to register with the upper series of ports of the cylinder, at least one of said slide valves lying in contacting relationship with one of the surfaces of the cylinder, a linkage connected with at least one slide valve, means associated with the linkage for constraining the two slide valves to move in opposite directions and to register simultaneously through their upper ports with the upper series of ports in the cylinder for covering and uncovering same, the cycle of operation of the slide valves including a comparatively long period of small oscillations during which the upper and lower series of ports in the cylinder are closed, following which a high acceleration leads to the uncovering and covering at a high speed of the upper series of ports in the cylinder through simultaneous registering thereof with the upper ports in both slide valves to provide a high speed opening with a large throughput area for said ports, after which the upper and lower series of ports in the cylinder are covered again, the piston cooperating with the first slide valve for controlling the lower ports in the cylinder for uncovering and covering same through a movement of the piston that is simultaneous with and in opposite direction with reference to the lower series of ports in the rst slide valve, a shifting in time being provided between the uncovering of the upper and of the lower series of ports in the cylinder.

6. In an engine of the two stroke internal combustion type, the combination of at least one cylinder provided in its wal1 with an annular series of ports at either of its ends, a gas feeding pipe communicating with one series of ports at the upper end of the cylinder, a gas feeding pipe opening into the other series of ports at the lower end of the cylinder, a driving piston adapted to reciprocate inside the cylinder and to uncover in its downward stroke, the ports corresponding to the lower cylinder, a slide valve provided with two annular series of ports adapted to register respectively with one series of ports in the cylinder wall, a further slide valve coaxial with the 1'irst slide valve and provided with ports registering with the upper ports in the cylinder wall and at the same time with the corresponding ports in the rst slide valve for a predetermined position of said slide valve and means controlling simultaneously the movement of the second slide Valve in the same direction as the piston and that of the rst slide valve in the opposite direction with a shifting in time between the simultaneous uncovering of the upper ports by the corresponding ports of the two slide valves and that of the lower ports by the piston and second slide valve.

'7. In an engine of the two stroke internal combustion type, the co-mbination of at least one cylinder provided in its wall with an annular series of ports at either of its ends, a gas feeding pipe communicating with the upper seriesof ports, a gas feeding pipe opening into the lower series of ports, a piston adapted to reciprocate inside the cylinder and to uncover at the end of its downward stroke, the ports corresponding to the second pipe,` at least one slide valve provided with an annular series of ports and adapted to slide over the cylinder wall into and out of a position for which its ports register with a predetermined series of ports in the cylinder wall, means controlling said slide valve including an eccentric operatively connected with the piston and a link system connecting said eccentric permanently with the slide valve for causing it to sweep past the corresponding series of ports in the cylinder wall at a speed that is high between the moments of uncovering and of covering said cylinder ports while slowing down the movement of said slide valve during the periods during which the series of ports considered are out of register.

S. In an engine of the two stroke internal combustion type, the combination of at least one cylinder provided in its wall with an annular series of ports at either of its ends, a pipe communicating with the upper series of ports, a pipe opening into the lower series of ports, a piston adapted to reciprocate inside the cylinder and to uncover at the end of its downward stroke, the ports corresponding to the second pipe, at least one slide valve provided with at least one annular series of ports adapted to slide over at least one cylinder wall into and out of a position for which its ports register with a predetermined l series of ports in the cylinder wall, means controlling said slide valve including a cam system operatively connected with the piston and a positively operated linkage between said cam system and the slide valves for causing them to sweep past at least one corresponding series of ports in the cylinder wall at a full speed between the moments of uncovering and of covering said cylinder ports while slowing down the movement of said slide valves during the periods during which the series of ports considered are out of register.

9. In an engine of the two stroke internal combustion type, the combination of at least one cylinder provided in its wall with an annular series of ports at either of its ends, a pipe communicating with the upper series of ports, another pipe opening into the lower series of ports, a piston adapted to reciprocate inside the cylinder and to uncover in its downward stroke the ports corresponding to the second pipe, coaxial slide valves adapted to move over one cylinder wall and having an annular series of ports adapted to register at a predetermined moment of their movements with one another and with i6 the ports in the cylinder wall and means con-I trolling the movements of said slide valves vin opposite directions, including Vat least one eccentric operatively connected with the piston and means connecting the two slide valves to move same in opposite directions and controlled positively by said cam system.

l0. In an engine 01" the two stroke internal combustion type, the combination of at least one cylinder provided in its wall with an annular series of ports at either of its ends, a pipe com-4 municating with the upper series of ports, another pipe opening into the lower series of ports, a piston adapted to reciprocate inside the cylinder and to uncover in itsl downward stroke, the ports corresponding to the second pipe, coaxial slide valves adapted to move over the cylinder Wall and having an annular series of ports adapted to register' at a predetermined moment of their movements with one another and with the ports in the cylinder walls and means controlling the movements of said slide valves in opposite directions including at least one eccentric operatively connected with the. piston and a compensating` bar lconnecting the two slide valves to move same in opposite directions and controlled positively by said cam system. i

l1. In an internal combustion engine, the combination of two coaxial slide valves deiining a cylindrical chamber and provided respectively with one and with two annular series of. ports, the first of which is adapted to register with that in the first slide valve, a piston adapted to reciprocate inside said cylindrical chamber and to uncover at the end of its stroke the second annular series of ports in the second slide valve and means mechanically interconnecting the piston with each of the two cylindrical members for constraining the latter to move in opposite directions with reference to the piston so as to bring the ports in the first cylindrical member into register with the second series of ports in the second slide valve at a predetermined moment with reference to the uncovering of the second series of ports in the second slide valve by the piston and two pipes communicating respectively with the rst two series of ports when registering with one another and with the last series of ports when uncovered by the piston.

12. In a two stroke engine, the combination of a cylinder wall provided at each end with an annular series of ports, two pipes opening respectively into the corresponding series of ports, at least one cylindrical slide valve cooperating with said cylinder wall and of which at least one lies in direct contacting relationship with said cylinder wall, and each slide valve being provided with at least one series of ports adapted to register with the corresponding ports in the other slide valve and in the cylinder wall, a piston slidingly engaging the cylinder and valve system, mechanical means controlling positively the oper-` ation of the valves and means permanently and mechanically connecting the piston with the said mechanical means to constrain the ports in at least one slide valve to execute rst slight oscillations during a comparatively long time and then to move at a very high Velocity for uncovering and covering the registering ports during a very short time over a large area, the piston being adapted to cooperate in the uncovering of the lower ports with a shifting in time between the uncovering and covering of the two series of ports.

13, In a two stroke engine, the combination of a cylinder wall provided at each end with an 1 l annular series of ports, two pipes opening respectively into the corresponding series of ports, two cylindrical slide valves cooperating with said cylinder wall and lying respectively in contacting relationship with each side of the cylinder wall and each slide valve being provided with at least one series of ports adapted to register with the kcorresponding ports in the other slide valve and in the cylinder wall, a piston slidingly engaging the cylinder and valve system, mechanical means controlling positively the operation of the valves and means permanently and mechanically connecting the piston with the said mechanical means to constrain the ports in the slide valves to move at a very high velocity into and out of register with the corresponding cylinder wall valves, the piston being adapted to cooperate in the uncovering of the lower ports with a shifting in time between the uncovering and covering of the two series of ports.

14. In a two stroke engine, the combination of a cylinder wall provided at each end with an annular series of ports, two pipes opening respectively into the corresponding series of ports, two cylindrical slide valves cooperating with said cylinder wall and lying respectively for the first slide valve in contacting relationship with the cylinder wall and for the second slide valve with the surface of the rst slide valve that is not in contact With the cylinder wall, and each slide valve being provided with at least one series of ports adapted to register with the corresponding ports in the other slide valve and in the cylinder wall, a piston slidingly engaging the cylinder and valve system, mechanical means controlling positively the operation of the valves and means permanently and mechanically connecting the piston with the said mechanical means to constrain the ports in the slide valves to move at a very high velocity into and out of register with the corresponding cylinder wall valves, the piston being adapted to cooperate in the uncovering of the lower ports with a shifting in time between the uncovering and covering of the two series of ports. '15. In a two stroke engine, the combination of a cylinder wall provided at each end with an annular series of ports, two pipes opening respectively into the corresponding series of ports, at least one cylindrical slide valve cooperating with said cylinder wall and of which at least one lies in direct contacting relationship with said cylinder wall, and each slide valve being provided with at least one series of ports adapted to register with the corresponding ports in the other slide valve and in the cylinder wall, a piston slidingly engaging the cylinder and valve system, mechanical means controlling positively the operation of the valves and means permanently and mechanically connecting the piston with the said mechanical means to constrain the upper ports of the two slide valves to move simultaneously in opposite directions in front of the upper ports of the cylinder for covering and uncovering same at a high speed, the piston being adapted to cooperate in the uncovering of the lower ports with a shifting in time between the uncovering and covering of the two series of ports.

16. In a two stroke engine, the combination of a cylinder wall provided at each end with an annular series of ports, two pipes opening respectively into the corresponding series of ports, two cylindrical slide valves cooperating with said cylinder wall and lying respectively in contacting relationship with each side of the cylinder wall, and each slide valve being provided with at least one series of ports adapted to register with the corresponding ports in the other slide valve and in the cylinder wall, a piston slidingly engaging the cylinder and valve system, mechanical means controlling positively the operation of the valves and means permanently and mechanically connecting the piston with the said mechanical means to constrain the upper ports of the two slide valves to move simultaneously in opposite directions in front of the upper ports of the cylinder for covering and uncovering same at a high speed, the piston being adapted to cooperate in the uncovering of the lower ports with a shifting in time between the uncovering and covering of the two series of ports.

17. In a two stroke engine, the combination of a cylinder wall provided at each end with an annular series of ports, two pipes opening into the corresponding series of ports, two cylindrical slide valves cooperating with said cylinder wall and lying respectively for the rst slide valve in contacting relationship with the cylinder wall and for the second slide valve with the surface of the iirst slide valve that is not in contact with the cylinder wall, and each slide valve being provided with at least one series of ports adapted to register with the corresponding ports in the other slide valve and in the cylinder wall, a piston slidingly engaging the cylinder and valve system, mechanical means controlling positively the operation of the valves and means permanently and mechanically connecting the piston with the said mechanical means to constrain the upper ports of the slide valves to move simultaneously in opposite directions in front of the upper ports of the cylinder for covering and uncovering same at a high speed, the piston being adapted to cooperate in the uncovering of the lower ports with a shifting in time between the uncovering and covering of the two series of ports. Y

18. In a two stroke engine, the combination of a cylinder wall provided at each end with an annular series of ports, two pipes opening into the corresponding series of ports, two cylindrical slide valves cooperating with said cylinder wall and of which at least one lies in direct contacting relationship with said cylinder wall, and each slide valve being provided with at least one series of ports adapted to register with the corresponding ports in the other slide valve and in the cylinder wall, a piston slidingly engaging the cylinder and valve system, an eccentric controlling lpositively the operation of the valves and means permanently and mechanically connecting the piston with the said eccentric to constrain the ports in the slide valve to move at a very high velocity into and out of register with the corresponding cylinder wall valves, the piston being adapted to cooperate in the uncovering of the lower ports with a shifting in timebetween the uncovering and covering of the two series of ports.

19. In a two stroke engine, the combination of a cylinder wall provided at each end with an annular series of ports, two pipes opening respectively into the corresponding series of ports, two cylindrical slide valves cooperating with said cylinder wall and of which at least one lies in direct contacting relationship with said cylinder wall, and each slide valve being Aprovided with at least one series of ports adapted to register with the corresponding ports in the other slide valve and in the cylinder wall, a piston slidingly engaging the cylinder and valve system, a cam JACQUES EGIDE sERsT. JACQUELINE ,sERsT TEPLOW. PAUL sERsTE.

PIERRE sERsT.

14 REFERENCES CITED The following references are of vrecord in the le of this patent:

UNITED STATES liATENTs Number 15 Number Name Date Peache Apr. 23, 1912 Pringle May 25, 1915 Stokes July 1, 1919 Cage Aug. 2, 1921 Bischof Dec. 3, 1935 Allyn Apr. 1, 1941 FOREIGN PATENTS Country Date France of 1939