US2156470A - Distribution mechanism for machines of the piston type and especially steam engines - Google Patents

Description

May 2, 1939. J. BUGATTl 2,156,470

DISTRIBUTION MEGHANISM FOR MACHINES 0F THE PISTON TYPE AND ESPECIALLY STEAM ENGINES Filed July l5, 1936 5 Sheets-Sheet l .f/llllif//ZV n hlla. i

4 fr m6 J. BUGATTI May 2, 1939.

DISTRIBUTION MECHANISM FOR MACHINES OF THE PISTON TYPE AND ESPECIALLY STEAM ENGINES Filed July l5, 1936 5 Sheets-Sheet 2 @W f T //V//////////////V W/ J. BUGATTI May 2, 1939.

' DISTRIBUTION MECHANISM FOR MACHINES oF THE PIsIoN TYPE AND ESPECIALLY STEAM ENGINES 5 Sheets-Sheet 3 Filed July 15, 1936 May 2, 1939.

2,156,470 TON v 5 Sheets-Sheet 4 J. BUGATTI Filed July l5, 1936 lim . TYPE AND ESPECIALLY STEAM ENGTNES DISTRIBUTION MEGHANISM FOR MACHINES A OF THE PIS May 2, 1939- J. BUGATTI 2,156,470

DISTRIBUTION MECHANISM FOR MACHINES OF THE PISTON TYPE AND ESPECIALLY STEAM ENGINES Filed July 15, .1936 5 Sheets-Sheet 5 Patented May 2, 1939 UNVE'E@ nidad@ STEAM ENGENES Jean Bugatti, Molsheim, France Application July 15, 1936, Serial No. 90,816

In France September 16, 1935 14 Claims.

The correct utilization of high pressure steam in machines of the piston type gives rise to difculties. One of these diiculties, which is not the less important, lies in the provision of a satisfactory distribution. The standard distribution by means of slide valves permits of obtaining neither a high speed of revolution of the engine nor a full expansion in a single cylinder. Wiredrawing of steam constitutes a serious drawback. Distribution by means of lift valves or oscillating valves is advantageous over distribution by means of slide valves only at the cost of important mechanical complications. The presence of members that are often heavy, subjected to sudden Variations of speed and 'of direction oi' motion renders these systems rather delicate.

If it is desired to devise an engine capable of running at high speeds in which high pressure steam is utilized under good conditions, it is necessary, as it is Well known, to admit steam through orifices that are widely opened for a very short portion of the stroke of the piston, in such manner that, on the one hand, steam lls up nearly instantaneously, without undergoing any substantial wiredrawing, the chamber of relatively small volume existing at this time inside the cylinder, and, on the other hand, this steam expands for the remainder of the stroke of the piston, that is to say for a large portion of this stroke.

The object of the present invention is to provide a distribution mechanism. or valve motion and also an engine which comply with the requirements above stated. Although the distribution mechanism and the engine according to the present invention are intended for the production of motive power from` steam and especially high pressurev steam, they are not limited, in

their applications, to this particular case, but, in the following specification, reference will be had more particularly to this application.

The essential feature of' the distribution mechanism according to the present invention lies in the fact that it includes, for controlling the admission into the cylinder, two superposedv slide valves or sleeves which are arranged to move in opposite directions with a reciprocating linear motion in close proximity to the cylinder head,

these values being provided with intake ports for admission of fluid to the cylinder and being arranged in such manner that their respective ports register with each other when they are moving in opposite directions with their maximum velocity or with a velocity nearly equal to (Cl. 121-129) e said maximum Velocity. Owing to this arrangement, admission takes place in a very short time, since the edges of the variable slot through which steam can enter the cylinder move toward each other with a relative velocity equal to the sum of the individual velocities of the slide valves and said valvesy are, at this time, moving with their maximum velocity or with a velocity nearly equal to this maximum value. This is a great diiierence with what takes place in ordinary distribution systems including slide valves, in which admission takes place at the end of the stroke, that is to say for a velocity of the parts which is nearly zero. It should be noted that this result is obtained in a very simple manner without making use of elements having sudden displacements.

In order that the motive fluid may be admitted into the cylinder through a passage of an area as large as possible, the reciprocating valves advantageously consist of two sleeves surrounding the cylinder and provided with ports whichv extend over a very large portion of their periphery. This arrangement has the further considerable advantage that the pressure exerted by the iiuid on the sleeves, before or after the admission of said fluid, does not increase the effort to be exerted for moving said sleeves.

Finally, in order to adjust the degree of admission, the arrangement according to the present invention includes, in combination with the reciprocating elements above referred to, a sliding cut-off control member, which is preferably disposed on said elements and which can be displaced at will. When the reciprocating elements above referred to consist of sleeves, this cut-off control memberalso consists of a sleeve superposed to the sleeves above referred to. Of coure, Vthis control member may, according as the case may be, be actuated through a manual control and/or an automatic control influenced by a governor, such, for instance, as a centrifugal governor.

It will be readily understood that, with a distribution mechanism of the above set forth character, the path of steam from the intake control valve to the cylinder chamber is minimized and this feature is highly valuable in the case of' a high efficiency engine having aA high Working speed.

The same reciprocating sleeves may also, advantageously serve to control the exhaust. It suffices to provide .them with ports disposed in such manner that exhaust takes place during the desired portion of the piston stroke.

Another object of the present invention is to provide an engine embodying the distribution mechanism above described.

The essential feature of this engine lies in the fact that the distributing sleeves corresponding to one end of the cylinder are guided, on the one hand, in the bore of the cylinder and, on the other hand, on a. part carrying or constituting the cylinder end, and that the piston is a stepped piston slidably engaging both the inner sleeve and the cylinder wall, owing to vwhich the various members having reciprocating motions are perectly guided in their movements. Furthermore, since the inner sleeve constitutes one of the walls of the chamber in which the piston is moving, the clearance space is reduced to a minimum.

Preferably, the cylinder is a single action cylinder, that is to say steam is received upon only one face of the piston. It is surrounded with two contiguous chests, or jackets, one of which forms an intermediate reservoir for live steam while the other serves to discharge exhaust steam. Owing to the reserve supplied by the large steam box formed by the first jacket and owing to the immediate vicinity of the working chamber of the cylinder, the intake pressure may remain substantially equal to the pressure ofv the boiler, even at high speeds. The jackets further contribute to avoid heat losses in the cylinder, to reduce condensations, and also to prevent damage arising from sudden condensation of a large quantity of water. In order to permit the easy removal o-f the condensation water that may be formed, according to the invention, I provide in the cylinder one or more leakage orifices opposite the middle part of the piston, between the zone in which the portion of larger diameter of the stepped piston operates and the Zone in which the sleeves are moving. When the cylinder is vertical, it is advantageous to give the piston head an outwardly projecting rounded shape, so as to facilitate the escape of condensed water toward the sleeves.

The reciprocating sleeves may be driven through cranks or eccentrices, turning in the same direction, respectively and driven by the engine shaft. A controlrmechanism may be provided so as to permit of giving angular relative displacements to these cranks or eccentrices when it is desired to vary the direction of working'. The cut-off control sleeve which surrounds the reciprocating sleeves is mounted in such manner as to cooperate with a stationary annular seat provided in the cylinder, the steam inlet passage being 4defined by the gap between said seat and the adjacent edge of the cut-off control sleeve. Through a suitable adjustment of the reciprocating sleeves, it is possible to obtain that admission begins to take place at a predetermined, stationary point and the end of the admission takes place at a variable point depending upon the position of the cut-oif control member. Under these conditions, the period or duration of admission can be modied merely by displacing the cut-off' control member, and, for instance, it is possible, in order to facilitate starting, to admit steam for a substantial portion of the piston stroke.

Of course, a multi-cylinder engine may be formed by disposing, preferably side by side, so as to form a compact engine unit, a. plurality of cylinders arranged as above described. The cylinders may be integral with one another or they may be assembled to one another. A jacket or steam box may be made common to several or all of the cylinders, and this for admission, for exhaust, or for both. The grouping of several cylinders into a single unit may be employed for devising a compound engine, for instance an engine including one high pressure cylinder and two low pressure cylinders, especially when very high pressure steam is employed. In this case, direct communication may be established between the exhaust jacket of a high pressure cylinder and the intake jacket of a low pressure cylinder, in such manner that heat losses may be reduced to a minimum.

An engine of this kind, of the simple or double expansion type, including a great number of elements or cylinders, so that said elements may be of small size, might, owing to itsI construction, constitute a light-weight structure. Associated with a suitable boiler, this engine might be utilized in automobile or aviation industries.

Preferred embodiments of the present invention will be hereinafter described, with reference to the accompanying drawings, given merely by way of example, and in which:

Fig. l is a transverse sectional View of the engine according to the invention;

Fig. 2 is a partial longitudinal section of an engine of this kind including a plurality of cylinders;

Fig. 3 shows, on an enlarged scale, a simplified detail of the structure of Fig. 1, this figure show- I ing the position of the ports of the sleeves', of the connecting rods and of the cranks for the position corresponding to full admission;

Figs. 4 and 5 are similar views corresponding to the positions of the partsl at the beginning of the admission period and at the end of the admission period, respectively;

Fig. 6 shows, in the same'manner, the position of the distribution sleeves. half a turn after full admission;

Fig. '7 is a plan-view, partly in section, showing a mechanism for angularly displacing the sleeve control crankshafts with respect to each other.

Cylinder l carries crankshaft 2 through bearings i-lxed in its under face. A casing 3 closes the lower part and serves to collect the oil through which the movements are lubricated.

Cylinder l is closed, at the top, by a cylinder head 4 arranged coaxially with the cylinder bore and through which pass control rods 5 for the distribution sleeves. These rods are thus guided and pass in stuling boxes included in this cylinder head. The lower part of the cylinder head carries a spring-loaded safety valve 6 for preventing any over-pressure, and especially for avoiding breakage in case of sudden condensation of a substantial quantity of water.

On either side of the cylinder, there are provided chests or jackets for the admission and the exhaust of steam. These chests communicate with the cylinder through apertures and they are provided, in their central part, with flanges in line with the outer surface of the cylinder and permitting connection with the boiler or with the condensers, and even with the adjacent cylinders when the engine is of the multi-cylinder type.

Steam is admitted through chest or chests 'l and escapes from the cylinder through chest or chests 8 after having worked in the cylinder.

Piston 9 is connected through a rod I0 to crankshaft 2. It is of the stepped type and includes two series of packing rings. The upper portion of this piston slides in the inner distribution sleeve and works in the same manner as an ordinary Cil piston moving in a cylinder. The lower portion of the piston slides in the cylinder and also ncludes a series of packing rings. These rings serve, for instance, to stop condensation water which, otherwise, would drop into the crankcase. The upper packing ring reaches, at the end of the upward stroke, the lower edge of orifices 22, called draining orices, through which condensation water and the excess of the lubricating oil are driven out when the piston is moving upwardly.

The displacement of the two distribution sleeves is ensured through two crank shafts I I, I I', turning at the same speed as the crank shaft of the engine and driven from said shaft 2 through a train of loose gears having parallel axes or through any other suitable control system. The control system shown on Fig. 1 includes a bevel-gear 35 on crank-shaft 2, a bevel-gear 39 on crank-shaft I I and a revoluble connecting rod 31 having bevelgears 36, 38 meshing with bevel-gears 35Vand 39 respectively; motion is transmitted from crankshaft II to crank-shaft I I by means, the preferable form of which will be hereinafter described with reference to Fig. 7.

In the embodiment of Fig. 1, the shaft II on the left hand side serves to drive, through crank I2, the outer distribution sleeve I3 and the shaft I I on the right hand side serves to drive, through crank Iii, the inner distribution sleeve I5. These cranks i2 and I4 are operatively connected with connecting rods I6 which transmit their movement to the ends of control rods mounted on the distribution sleeves.

Telescopic casing Il surrounding these rods extend from the casings ZI of the crankshafts I I to cylinder head li, with a view to ensuring lubrication of the moving elements such as connecting rods, guiding rods, etc., and the return of oil tothe lower part of the engine.

The outer sleeve, or cut-01T control sleeve I8, is movable vertically through a manual control (diagrammatically illustrated by a control rod 4I!) which may be operated by the driver. The lower edge of the cut-off control sleeve I8 is adapted to cooperate with an annular seat or step M for cutting off the steam supply to the engine cylinder bore when said control sleeve is in its lowermost position. When the control sleeve assumes a higher position, its lower edge spaced apart from seat Gi uncovers ports IQ in the chest or chests i and more or less throttles, according to its actual position, the steam passage from said chest or chests to the cylinder bore.

The two other sleeves, to wit sleeves I3 and I5, called distribution sleeves, are provided with suitably located ports and are reciprocable within the cut-off control sleeve I8. On the one hand, these distribution sleeves slide inside each other, and on the other hand the inner sleeve I5 slides on the inwardly projecting portion of cylinder head d and on piston e. The outer sleeve I3 slides in cylinder I and in the cut-off control sleeve The lower edges of the ports provided in these distribution sleeves are in register in the position called full admission position (Fig. 3). In this position, the lower edge of the ports I9 of chest Vor chests I and the upper edge of piston 9 are in line with the lower edges of the ports in the distribution sleeves I3 and I5.

The beginning of admission takes place (Fig. Ll) v is thus seen that admission begins to take place at a stationary point and at a moment (during the stroke of piston S) which depends only upon the relative angular position of crank I4 with respect to the crank pin of the crank-shaft operated by rod III (Fig. 1).

Admission is ended when the lower edge of the port in the outer sleeve I3 (which, for the direction of rotation that is considered, is moving upwardly) passes opposite the lower edge of the cut-off control sleeve I8 (Fig. 5).

The closing point is therefore variable in accordance with the position occupied by the cut-off control sleeve I8, the duration of admission or intake increasing when the driver moves this sleeve in an upward direction.

The so-called full admission period corresponds to the time at which cranks I2 and I4, corresponding to distribution sleeves I3 and I5 respectively, are at right angles to the axes of connecting rods IS (Fig. 3). The speeds of translation of the sleeves are therefore of the same value but of opposite directions, this value being the maximum value of said speeds for a given speed of revolution of the engine.

For a revolution of the crankshaft and therefore a revolution of each of these cranks I2 and III, there exist two positions for which the lower edges of the sleeves are aligned. The rst, which is the full admission position, has just been examined. The second, which occurs half a turn subsequently (Fig. 6), corresponds to cranks I2 and I4 (which operate sleeves I3 and I 5) being again located in the same horizontal line. It will be seen that, in this position, the ports of the sleeves are wholly masked by cylinder head II.

The direction of working is reversed by angularly kdisplacing the crankshafts with respect to each other. For this purpose, these crankshafts are connected to the engine crankshaft 2 through a device enabiing such displacement. In.` the present instance, I have shown in this connection on Fig. 7, an arrangement analogous to that illustrated in U. S. Patent 1,837,813. Upon the spindle 28 of crankshaft II is keyed a helical gear while another helical gear 26 is slidably mounted on the spindle 29 of crankshaft II, through a spiined sleeve 39; sleeve 3i! is coupled with another sleeve SI carrying a further helical gear 27, through a rigid arm 32, sleeve 3i is slidable on an auxiliary spindle 33, and the sleeves are movable for adjustment by a control conventionally shown as a screw 3d; helical gear 2'! meshes both with helical gear 25 and helical gear 23.

The durations of intake, which are reduced as much as possible for normal working, may be increased in order to facilitate starting of the engine. Otherwise, there would be the risk, in the case of a multi-cylinder engine, of having all the cylinders separated or cut-off from the steam main. The displacement of the cut-off control sleeve toward the top delays (as above explained) the end of the intake and, inthe case of an engine including a plurality of cylinders the respective crank pins of which are at 90 from one another, it is possible to prolong the duration of admission of one cylinder beyond 90. Thus, the engine has, in all cases, a cylinder in communication with the intake main.

The exhaust is controlled through a second' Cil the inside of the cylinder with the exhaust chest or chests 8, disposed under the intake chest or chests It should be noted that, as in the case of admission, there exist two positions in which the exhaust ports register with one another, one of these two positions being an inoperative position because it corresponds to the ports being masked by the piston. Accordingly exhaust cannot take place for this position, which is close to the end of the upward stroke.

Fig. 2 shows how a multi-cylinder engine can be devised for practical purposes. In this figure, itV has been assumed, although this corresponds only to one particular embodiment, that the cylinders form a single unit and that the cylinder heads 4, d', etc. are separate and are kept in coaxial relation with the corresponding cylinders for instance by having their edges engaged in the respective top parts of the cylinders, these cylinder heads being eventually assembled together through suitable means.

While I have, in the above description, disclosed what I deem to be practical and efficient embodiments of the present invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the appended claims.

What I claim is:

l. In an engine having a cylinder and a passage for admitting fluid to said cylinder, the combina- Vtion of two reciprocable valves having corresponding inlet ports for controlling said passage; first driving means for reciprocating one of said valves at periodically varying speeds including a range of maximum speeds; and second driving means for reciprocating the second valve at periodically varying speeds including a range of maximum speeds; the first and second driving means being so arranged and timed that the corresponding inlet ports in the valves are in register while said valves move in opposite direction at speeds lying, for both valves, in their respective ranges of maximum speeds.

2. In an engine having a cylinder and an intake passage for admitting fluid to said cylinder, the combination of two reciprocable slide valves having corresponding inlet ports adapted to cause admission oi iiuid to said cylinder when they are in register; rst driving means for imparting to one of the valves a reciprocatory motion at variable speeds including a range of maximum speeds; and out-of-phase second driving means for imparting a similar reciprocatory motion to the other valve; the first and second driving means being so arranged and the out-of-phaseY difference so selected that the corresponding inlet ports in the valves are operatively in register while the valves move in opposite direction at speeds lying, for both valves, in their respective ranges of maximum speeds.

3. In a sleeve valve control mechanism for reciprocating engines, the combination of two ported valves, two revoluble driving means for reciprocating said valves and two connecting members operatively interposed between the valves and the respective driving means therefor, the phase relation between the revoluble driving members being substantially equal to 180 minus the maximum angularity, in operation, between the two connecting members.

4. In a reciprocating engine having a cylinder, a crankshaft and an intake passage for admit- -ting fluid to said cylinder, the combination of two cooperating intake slide valves adapted to control the iiow of uid to said cylinder in said passage, the valves having corresponding intake ports; first revoluble means driven at crankshaft speed for imparting a reciprocatory linear motion to one of said valves; a rst driving member operatively interposed between said iirst revoluble means and the corresponding linearly reciprocable valve; second revoluble means also driven at crankshaft speed for imparting a reciprocatory linear motion to the other valve; a second driving member operatively interposed between the second revoluble means and the corresponding linearly reciprocable valve; the revoluble means having an out-of-phase difference equal to 180 minus the maximum angularity, in operation, between said driving members.

5. In a reciprocating engine having a cylinder and a crankshaft, the combination of a couple of cooperating ported sleeves slidably reciprocable in the cylinder bore in timed relation with the crankshaft, for controlling intake, with an adjustable sleeve disposed in coaxial relation with the reciprocable sleeves and in slidable contacting relation with one of said sleeves, for imposing a supercontrol on the intake.

6. A distribution mechanism for the control of fluid admission from an intake passage to cylinder bore, which comprises three sleeves disposed within one another and in the cylinder bore, one of the said sleeves being movable independently of the other sleeves and forming a gate valve with respect to said intake passage while the other valves are correspondingly ported, and driving means for imparting out-oi-phase reciprocatory motions to the ported valves.

7. In an engine, the combination oi a cylinder having an open end bore and an annular seat around the open end of the bore; a control sleeve mounted in coaxial relation with said open end bore but outside the same and adapted to dene, between said seat and its adjacent edge, an adjustable intake port for admission of iluid to said bore; two axially reciprocable sleeves mounted within said bore and the'control sleeve, in coaxial relation therewith, said reciprocable sleeves having corresponding ports adapted to cause admission of iiuid to said bore when they are in register opposite the adjustable intake port; and driving means for imparting out-oi-phase reciprocatory motions to the ported valves.

8. In an engine, the combination of a cylinder having an open end bore and an annular seat around the open end of the bore; a control sleeve mounted in coam'al relation with said open end bore but outside the same and adapted to define, between said seat and its adjacent end, an adjustable intake port for admission of fluid to said bore; two axially reciprocable sleeves having corresponding ports adapted to cause admission of fluid to Said bore when they are in register opposite the adjustable intake port; and driving means for imparting out-of-phase reciprocating motions to the ported valves, adapted and arranged to move the ported valves in opposite directions at speeds substantially equal to their respective maximum speeds when the ports in said valves are in register opposite the adjustable intake port.

9. In an engine, the combination of a cylinder having a bore and a fluid intake passage opening into said bore; a couple of ported intake control sleeves reciprocably mounted in said bore; and adjustable throttling means operatively interposed between the mouth of said passage and the intake control sleeves, for regulating the flow of fluid from said passage to said cylinder bore.

10. In a piston engine, the combination of two reciprocable ported sleeves adapted to control admission of fluid from outside the outer sleeve to within the inner sleeve, and coaxially arranged adjustable sleeve means disposed in contacting relation with one of the reciprocable ported Sleeves for throttling the flow of iiuid from outside the outer sleeve to within the inner sleeve, the space within the inner sleeve forming a working chamber for the engine piston.

11. In a steam engine, the combination of a cylinder; two reciprocable concentric sleeve valves in said cylinder having cooperating steam intake ports; a stepped piston having a head portion slidably movable in the inner sleeve valve and a skirt portion slidably movable in said cylinder in a Zone remote from the working Zone of' the reciprocable sleeve valves; said cylinder being further provided with a steam inlet port in the reciprocable valve working zone and a discharge outlet port between the last named zone and the Working Zone of the piston skirt portion, for removing any condensed steam.

12. A combination as claimed in claim 11, further comprising an adjustable sleeve disposed in concentric relation around the outer sleeve valve, said adjustable sleeve having an edge adapted for cooperation with an annular inner seat on the cylinder adjacent said steam inlet port so as to form therewith an adjustable steam passage.

13. In an engine, the combination of apcylinder comprising a body portion and an end portion, the body portion having an axial bore and a side inlet passage opening in said bore, While the end portion comprises an inwardly directed projection coaxially disposed with respect to said bore; a reciprocable inner sleeve movably disposed in said bore and extending around said projection so as to be guided thereby in its reciprocatory motions, the inner sleeve having an intake port adapted to cooperate with the end surface of said pro j ection for controlling the beginning of admission; a reciprocable outer sleeve movably disposed in said bore in sliding outer contact with the cylinder wall dening said bore, and in sliding inner contact with the inner sleeve, the outer sleeve having an intake port adapted to cooperate with the inner sleeve intake port for admission of fluid fr0-m said passage to said port; an adjustable cutoi control sleeve fitted over said outer sleeve, coaxially and in sliding contact therewith, adapted to throttle the mouth of the side inlet passage and also to cooperate with the outer reciprocable valve intake port for controlling the end of admission; driving means for reciprocating the inner sleeve and further driving means for reciprocating the outer sleeve, the driving means being soy timed and arranged that the inner sleeve is moved away from the cylinder end at a speed approximating its maximum, speed and the outer sleeve is moved toward the cylinder end at a speed approximating its maximum speed, while the inlet ports in the reciprocable valves register opposite the mouth of the side inlet passage.

14. A iiuid intake contrl mechanism for an engine cylinder, which comprises two reciprocable slide valves having corresponding intake ports; two revoluble driving members for said slide valves, adapted to revolve along circular paths having the same diameters; transmission means including a connecting rod operatively interposed between each driving member and the corresponding valve, for imparting to the latter a rectilinear reciprocatory motion; and driving means for revolving the driving members along their respective circular paths with a constant phase difference; the phase difference and the relative position of the intake ports being so selected that the latter are in register while the slide valves are moved in opposite directions and the connecting rods are substantially in tangential relation with respect to the respective circular paths.

, JEAN BUGATTI.

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