US1666630A - Motor-compressor apparatus - Google Patents

Description

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April 17, 1928. f

NVENTOR u/ gera; Hscara A www ATTORNEYS.

Aprilu, 1928.

R. P. PESCARA MOTOR COMPRESSOR APPARATUS Original Filed June 5. 1925 3 Sheets-Sheet 3 ATTORNEYS,

Patented Apr. 17, l1928.

f UNITED-STATES 1,666,636 PATENT OFFICE.

RAUL PATERAS PESCARA, F PARIS, FRANCE, ASSIGNOR TO THE PESCARA & RAY- MOND CORPORATION, 0F DOVER, DELAWARE, A CORPORATION OF DELAWARE.

MOTOR-COMPRESSOR APPARATUS.

, Original application led .Tune 5, 1925, Serial No. 35,249, and in FranceJune 11, 1924. Divided and this application led January 8, 1927. Serial No. 159,853.

This is a division from my application Serial No. 35,249 filed on the th June, 1925.

` This invention relates to machines which are at the same` time producers and trans- 5 formers of energy, for example, motor compressor units. v

The main object of the invention is to lincrease the eiiciency of the cycles at present employed in industry for the thermo-dynamic evolution of the gaseous masses intended v for combustion or arising from combustion,

in internal combustion engines, and forms,

in a sense, an improvement and refinement in the so-called two stroke cycle, combustion taking place under constant pressure'. y

rlhe present invention consists essentially in carrying out the following operations inside a cylindrical space, whose volumetric vcapacity is made to vary by the alternating movements of a gas-tight piston arranged therein, said cylindrical space having a very great ratio between'the length and the bore: 1. `Expanding the burnt gases arising from the combustion of a combustibleagent effected under constant pressure, carrying the expansion down to a pressure eventually equal to that of the surrounding atmosphere.

2. Causing the machine to suck in from the atmosphere a certain amount of pure air, which enters in the proximity of the combustion chamber and is drawn along in the wake ofthe burnt gases, cooling the walls as it follows the movement of the piston.

3. Utilizing the s eed acquired by this mass of air and by t 1e mass of burnt gases to cause the expulsion of a portion thereof when the movement'of vthepiston 'slackens 4. injecting air at -a low pressure for scavenging the cylinder.'

j the scavenging with pure air.

7. Compressing the air remaining in the cylinder until t e desired pressure is obwill benaturally extended, as also to any apparatus of any kind utilizing its principle, and to their separate parts.

The invention will be easily understood by lreference to the following description and also to the annexed drawings, which, however, are only given by wayof example.

Fig. 1 of said drawings, is 5a longitudinal section of a motor compressor unit constructed in accordance with thelinvention.

Figs. 2 and 3 are large scale sections show.- ing the Working of the device `for opening the storage valves.

Fig. 4 is a large scale section showing part of the starting device of the apparatus.

Fig. 5 is a large scale section of the cylinder head closing the cylinder'on the compresser side. t

According to the invention, and' more especially in accordance with the constructions to which the drawings refer, supposing it is desired to construct a motor compressor unit, this can be done as follows o r in some similar mannen In a fixed horizontal frame 10, whose interior is bored out, is arranged a cylinder 11 having an easy sliding t in the frame 10. The cylinder 11 is closed at one end by a cylinder head 12 rigidly connected thereto, and at the'other end by a head 13, mounted as will -be explained later on. A gas-tight piston 14 can reciprocate in the cylinder 11.

The combination of the piston 14 and the cylinder 11 forms then an oscillating system such that the piston 14 can reciprocate in the interior of the cylinder 11 while the cylinder 11 itself can reciprocate Iin the frame 10.

The cylinder head 12 has two passages 11F-15 to which correspond the valve 16 17 whose mov'ements'are controlled by the bent rocking levers 18-19, which are pivoted on the cylinder head 12 and carry the frollers `2() -21 co-operating with 'the fixed The passage 15 communicates freely with the atmosphere. The passage 14 terminates in a tube 24, outside the cylinderv and bent at a right angle. ,A This tube 24 slides inside a fixed casing in which it iitsforming a gas-tight joint. The arrangement thus allows the end portion of the oscillating cylinder 11 to be placed in communication with a storage reservoir 154 by means of the pipings 14, 24, 25, 26 and 155, the piping 26 being fixed. i The rocking lever 19 is ofthe ordinary type. The rocking lever 18 on the ,contrary may be of a type already described -in another application for patent led by me on the 5th June, 1925, Serial No. 35,250, or may be similar to the lever 34, hereinafter described and shown in detail in Figs. 2 and 3.

This rocking lever controls the opening and closing of the valve 16 when the-"cylinder 11 moves in the direction of the arrow 151. On the contrary, the valve 16 alwa s remains closed and, so to speak, integra with the cylinder 11 when this latter moves in the direction of the arrow 150.

The cylinder 11 also has one or more openings like those at 31, guarded by valves like 32,i opening from within outwards, and kept closed Aby sufiiciently strong springs such asv .2 and 3, on a large scale, which allows the following explanations to be easily under-- stood.

The rocking lever 34 is formed essentially of a forged piece pivoted about'the axis 37 in lugs 3.8 cast on the cylinder. This piece carries a fork 39 which acts on the head 40 of the valve 32 and a cylindrical extension 41 in the interior of which there moves a small piston 42 having the'form of a projectile. l

On the same axis 37 is mounted a pawl 43 which carries theft-axis 44.0f the roller 35. The pawl 43 is constantly pressed against the cam by the spiral spring 45 and a pro-y jection 46 of said pawl can enter the interior of the cylindrical cavity 41.

It will be understood from a comparison of Figs. 2 and 3, that according to the position ofthe piston 42 in the cylindrical cavity 41 and consequently of the projection 46, the. rocking lever can be locked to its pawl, or can, on the other hand, remain independent thereof. In the first case (Fi 3) the roller 35 on passing over the raise ortion ofthe cam controls the valve. In t 'e second case (Fig. 2), on the contrary, the valve v is not raised when the roller 35 passes over the raised portion of the cam. -The operation of this device will be explained later on.

The cylinder 11 carries (Fig. 1) a further series of ports 47 4capable of registering with corresponding openings 48 arranged 1n the fixed frame 10. All'the openings 48 lead into a peripheral passage 49 which opens at.- 50 into the exhaust tube placed perpendicu-l openings 52 are guarded by spring-actuated valves 53 and serve to place the interior of the cylinder 11 in communication with the4 compressed air reservoir 54.

The cylinder head 13 (Fig. 5) is provided with one or more passages as 55 whose opening into the interior of the cylinder is guarded by automatic suction valves '56. These valves are arranged -so that theycan open towards the interior of the cylinder 11 when acted upon by a diiference between the pressure existing in the passage 55 and the cylinder 11. In order to allow the atmospheric air to enter through the passages 55, the frame 10 is provided with openings as 57, which can register with the exterior mouths of the said passages 55. The openings 57 are guarded by safety valves 58 whose ob- `ject will be explained later on.

The head 12 is rovided with a device for injecting fuel un er pressure.. This device 128, whlch has been shown only diagrammatically, has nothi-ng novel as regards its construction and operation.. It is fed with oil under pressure through alfiexible tube 129. The injection nozzle 130 ends in a head 131jwhich meets, at the end of the stroke of the cylinder 11', towards the right (arrow 151) a fixed stop 132 whose position can be regulated by means of the screw 133.

In addition to these essential devices the apparatus is further provided withvarious scribed. Starting device- The object of this mech- 'anism is to automatically start the piston sure of the air in the reservoir 54. It communicates by the passage 64 with a chamber 65 closed at its lower end by the valve 66 and at its upper end by the valve 67. These two valves 66 and 67 are rigidly mounted von the same spindle 68.

The valve 67 is arranged in a cylindrical recess 69 communicating with the atmosphere by a passage 70. In the cylindrical recess 69 it acts as a gas-tight piston, that is to say, that when open or closed, it forms als . accessory mechanisms which will now be denis bev the pressure existing inthe reservoir 63 and, consequently, inthe chamber 65 The valve 66 guards the orifice l7l ar- ,be in no way hampered by the connection ranged in the fixed frame 10, which oriiice 71 can communicate in certain positions of the cylinder `11 vwith the slit 72 arranged in this latter.

. 4The reservoir 63 is also provided with a conduit 73 closed by a cock 74 whose plug can be actuated by means of a lever 75. On the other side of the cock 74 is a small auto. matic valve 76 closing the orifice of the passage 77.

This orifice 77 thus allows of communi cation between vthe reservoir 63 (through the tube 73, cock 74 'and valve 76) and i a cylinder' 78, whose axis coincides with that of the spindle 68 of the valves 66 and In the cylinder 78 there can move a gastight piston 79 rigidly lconnected to the spindle 68 and pressed downwards by a calibrated spring 80.

lt' will be noticed that the recess 69 is separated from the cylinder 78 by a screw' plug 81 and that there can beno communif cation between them.

A portion of the valve 76 has been shown on a large scale 'inFigz 4. lt vwill be seen that the valve 76 has a micrometric hole 82, Y `wh1ch moreover opens into anotherfanicrometric hole 83 drilled perpendicular to the first and passing right through the valve 76. |The operation of the whole device'will be i v explained later on.

Auwz'lary rotative device (Figs. 1 and 5).- Although, in principle, the apparatus shown in Fig. 1 does-not need any kinematic connection or any transformation of movement, it has been recognized that it might be useful in certain cases to have available a shaft revolving at a speed proportional to the number of reciprocations per second of the piston and cylinder. It is to be clearly (understood that'this shaft is notin any way intended to transmit energy tothe exterior of the apparatus, but to `allow of the linking up ofcertain apparatus found in commerce and in arotative form. Such, for example,

are, centrifugal governors, revolutipncounters which, in the present' case, may lbe utilizedfor measuring the number of lreciprocations, oil or' water pumps, diagramre-4 corders, etc. -v

To sum up, 1t is al questionthen of audevice which vis not essentialftorthe working ofv the motorcompressor unitfwlnch lshould fectly free.

lthe auxiliary rotative element that the oscillatory movements ofthe cylinder 11 shall between -it and the revolving shaft.'v It is de- 'sii-able that this shaft should have a fairly uniform speed of rotation, but on the other hand, the oscillations of vthe cylinder, supposing it to be perfectly free would take place according to a kinematic'law whichV it is too difficult to combine with any simple mechanism.

A mixed solution has therefore been adopted. and a kinematic coupling device employed such that, supposing the shaft turns uniformly, the movement of the cylinderlwould closely approach the theoreti cal movement itwould have if it were' per- 'lhis theoretical movementv is characterized by considerable accelerations at the beginning and end of the strokes and above all by a. great diii'erence in duration between the two successive strokes which lform one complete oscillation.

The coupling device vis therefore necessarily ofthe socalled quick return type, of which various forms are ordinarily employed in machine tools such' as planing machines, shaping machines and the like, but it presents in this case the. peculiarity-t'hat, conversely to what happens in machine tools, it is here the shaft which is driven instead of being the driving 1nember.

On vthe other hand, as caused by the'device vdo not correspond ex-l actly to the theoretical movement of a lfree cylinder, a certain freedom must be left yto the cylinder in its connection with the device, so as to preventl the transmission of any' considerable amount of power to the exterior of the apparatus,lwhich wouldhave means of `a nut 90. The whole is .enclosed in the cavity 85 by means of a threaded tube 91 forming an abutment for the vstop 88,' whereas another tube 191 forms an abutment for the stop 87.' The axis 486 is rigthe movements lUl) llo

idly connected to a cylindrical piece 92 which has an easy sliding it inside the sleeve- 91. This piece 92 has a transverse axis 93 on which is pivoted the foot ofconnecting nected -to a lever 97. The' latter is itself pivoted around a-fixed hollow axis 98 mounted in a casing integral with the.\ general44 ness of` thejoint, and bya cylindrical part frame 10 of the apparatus.

Besides this, said lever 97, is in form gen? erally pieces 100-101, slides'therein.

A crank shaft 102 rigidly connected to the shaft to which the uniform rotary movement is required to be given, has its crank pin 103 held between the two halves 100-I 101 of the piston and it is capable of passing.

through thelever 97 in which slots such` as 104 have been made for this purpose.

The crankshaft 102 actuates a centrifugal governor 125 acting tlirough the rod 126 on the supply of combustible oil.

Stabilization Device-It. is also necessary to redress perturbations which may occur in the movement of the apparatus and this is the object of the dfollowing stabilization device, whose operationwill be explained later and which is shown in Fig. 5.

On the bottom of the cylinder head 13 there is'ixed by meansvvof several tubular screw bolts such as 1053-106, a small reservoir of compressed air 107.l This reservoir 107 communicates, on the one hand, through the inside of the bolt 105 and the passages 108. and 109 with the interior of the cylinder 11. This communication can be intercepted by means of 4an automatic valve 110 held on its seatby a spring 111;

On the other hand the reservoir 107 is provided with a flexible tube'135 fixed to the lever 97 and communicating with a passage 112 arranged inside of the said lever 97. The hollow axis 98 is provided with an.0ri

' ce 113 which is capable ot' registering with the orifice 114 of rthe passage 112 when the lever 97 oscillates round its axis 98.

Finally, it will be seen in Fig. 1 that the hollow axis 98 communicates through its interior, by means of a tube 115 with the` reservoir 'of @Ompressed air 54.

Safety Device-It has been necessary to foresee also the case'ot1 a collision betweenv the piston and the cylinder, on the side of the cylinder head 13.

Fig. 1 shows, toprevent this, several annular spring rings 116 arranged in a recess -117 provided for this purpose in the piston 14. These rings bear, on the one hand, on a piece 118 acting as a buffer' and, on the lother hand, on `the body of the piston 14 by@ means of a special mounting easy to tubular and a piston, composed of two cylinder head 13, (Figs. 1 and 5) an abutment 119 carrying, a hollowed out plate 120 whose object is to prevent, inthe case of breakage of one of the valves 56, the

Vpossibility of any fragments or pieces ot' mechanism falling into the interior of the lcylinder 11.

On the other hand, the cylinder head 13 (Fig.) 5) is adjusted to the cylinder 11 by a conical part 121, which ensures the tight- 122. Behind the cylinder head 13 are arrange-d several other spring rings 123, by means of which andthe cover 124, the cylin-V der head 13 abuts against the cylinder 11 by means of the threadedring 125.` v

It will be easilyunderstood that in case of a collision between the buffer 118 of the piston-14 and the abutment119 of the cylinder head 13, the rings 116 and 123 will act as shock absorbers and prevent damage to the machine.

The apparatus described above operates in the following way:

The reservoir G3 being filled with compressed air as at suitable pressure, the piston 14 is so positioned that its edge, on the side towards the cylinder head 13, is flush with thel ports 72 of the cylinder 11. This can be done with the aid of a marked rod introduced into the cylinder 11 through an lopening in the head 12 closed by a suitable plug (not shown). Through thissame opening a little gasoline is injected into the cylinder 11.

The. piston 14 being positioned, the cylinderll is brought int'o a position marked beforehand, so that the openings`71 and 72 are in communication.

The lever, is then lactuated so that the cock 74 brings the tube 73 into communication with the cylinder 78. The compressed aiil of the reservoir 63 raises the valve 76 and acts then on the piston 79 which is driven' upwardly. The valve 66 gives passage to the compressed air from the reser- `voir 63, which fills the space included'bey pressed air injected between these two parts expands. The pressure falls rapidly to the atmospheric pressure. 'llhevspring 8O tends then to bring 'back the piston 79 to its orig inal position, driving before it the air filling the cylinder 78. This air can only be expelled through the micrometric openings 82 and 83 because the valve 76, has, at this moment, fallen back on its scat. The valve 66 then falls back slowly also on to its seat l and so closes the communication betweeny the reservoir 63 'and the cylinder 11`.

Itwill bel understood' that the device gives the following main results.

loo

Lacasse' apparatus for a certain initial pressure in the reservoir 63, so as to start the piston 14 and the cylinder 11 with the necessary and appropriate force, which force is always the same.

The piston 14 and the cylinder 11, having been started as just explained, compress between them the air in the cylinder space enclosed between the piston 14 and the cylinder head 12. ln the proximity of the dead point, thc pressure is .sufficient to ignite the .position shown in Fig. 2. Therefore, whenv gasoline charged compressed air.

From this instant on, the compressor motor unit is in its normal working condition and we shall now study what takes place successively in each stroke, and on each side of the piston, during a complete reciprocation.

Fm'w ard stroke.

il! 015m' sida-The explosion forces the piston 14 in the direction of the arrow 151 and the cylinder 11 in the direction 150.k

The expansion of the burnt gases goes on until the moment when the piston 14 reaches the exhaustl ports 47, the pressure in the cylinder then being eventually equal to that of the surrounding atmosphere. l

Y The ports 47 and 48 begin to coincide at the moment when the piston passes over them and at the same time the cam 23, acting on the valve 17, opens the orifice of the passage 15. The movement of the piston 14 continues, but with a tendency toslacken, so that the burnt gases 'following' it begin to escape through the openings 47.by reason of the speedl they have acquiredv behind the piston. At the same time an indraught of air is caused throughthe passages 15, which scavenges the burnt'gases still remaining in the cylinder. This pure air acquires also a certain speed which results in causing it to continue its scavenging movement, during the whole of the movement of the piston in the direction 151, between the openings 47 and deadpoint. f i' .f

During this forward stroke, the valve 32 is not lifted because at the moment of explosion the cylindersuddenl'y starts in the direction of the arrow 150, the resul'tbeing that the piston 42 is made to slide 1nto the the roller 35 passes over the raised portion of the cam 36 theprojection 46 lcannot actuate v150 by the bu the rocking, lever 34. On the other hand, the spring 33 is sufficiently strong to prevent any movement of the valve 32 due to the eli'ect of the expanding gases.

However, on arrivingat the end of the stroke, the acceleration of the cylinder is reversed, and the piston 42 tends by its inertia, to continue its motion in the direction of the arrow l150 since, at that moment, the roller 35 has already passed the raised -portion of the cam, and the pawl 43, therefore, is raised by the spring 45, and the piston 42 canvpass under the projection 46 and finally occupies the position shown in Fig. 3.

The valve 16 has also remained 0n itsv seat, its mechanism being similar to that of the valve 32. y

Compressor sida-The movement of the piston 14 and cylinder 11 has as a result the compression at first and afterwards the discharging, through the orices-51 and 52, to the reservoir 54, of the air which filled the cylinder 11 at the beginning of the stroke. This air has not been able to escape throu h the exhaust orifices 47, because these ony begin to coincide with the openings 48 when the face of the piston towards the head 13 has already passed the openings 47.

It is advantageous to so calculate the apparatus that the damping o f the lreciprocal movement of the cylinder 11 and the piston 14 takes place during 4the dischar e of the ment will be explained in connection with the operation of the stabilization device.

It will be noticed that in case of breakage of a valve such as 56, a large .portion of the air contained in the cylinder '11 would be driven out at the beginningof the stroke through the passage 55 then communicating through the openings 57 with the atmosphere. Under these circumstances avery violent collision might take place between the pistoni`14 andthe cylinder head 13. Ailthough considerably deadened by the colllssion device abovey described, it might-still be feared that such a violent encounter might cause serious damage to the machme.

The object ofthe safety lvalves 58 is precisely that of avoiding any escape of air b the passages 55 and the openings 57 whic Y they close directly any air current, however insignificant, *comesv to pass.' Under these circumstances the breakage `of an mtake valve no longer gives rise to ia. serious acv I cident.

Return stroke.

Umnpressor .sida-The cylinder 11 i forced back in the direction ofthe .arrow 151 and the piston in that of the arrow er of compressedair whlch is .at the pressure of the'reservoir 54 and has remained imprisoned between the piston 14 and the cylinder head 13 at the moment the movement has stopped.

When this buffer expands, itsv energy transforms itself into kinetic energy forthe piston and cylinder. When the expansion has been carried to a point slightly below the atmospheric pressure, the automatic valves 56 o en and permit the atmospheric air to fill t e cylinder 11, because at this moment, owing to the movement of the cylinder 11 in the direction 151 the passages 55 communicate with 'the atmosphere through the openings 57.

\ Just as in the forward stroke, there can be no communication with the exhaust assage 50 because the ports 47 cease to reglster with the openings 48 as soon as the face of the piston opposite the head 13 reaches the ports 47. v

M oto?" sz'daf-The piston begins by driving before it the burnt ases which have followed itin its movement in the direction 151) beyond the'openings 47 These burnt gases are forced to escape through the ports 47 because they encounter, opposite these ports,' the current of pure air coming from the bottom of the combustion chamber.

Moreover, during the stroke of the piston 14 (in the direction 150) between the dead point and the exhaust ports 47, the valves- 16 open and allow a current of air to pass.

.The exact moment for Vthe opening of said valves 16 is determined experimentally so that the air current to which they give passage may sustain the movement of exhaust of the burnt gases mixed with the scavenging air up to the moment of the closing of the ports 47.

The movement of the piston 1'4 and of the cylinder 11 continuing, the ports 47 close immediately the piston passes them. The valves 16 then also close in turn. J

There is then produced in the cylinder space included between the piston 14 and the cylinder head 12a slight compression of the air therein enclosed. At this moment thev storage valve 32 lifts, being actuated by the cam 36, the piston 42 being held by lthe projection 46 in the position of Fig. 3'; `A portion ofthe airis driven into thestorage reservoir 154 through the tube 153 having a sliding fit with respect to said reservoir. The reservoir 154 is fixed and carries the fixed cam 36. The whole structure compricing the lcam 36, the reservoir 154, the tubes 155 and 26, the cams 22 and 23, and the xedstop 132, 133 is a xed structure rigidly connectedv (in themanner shown) to some fixed base such as the frame 10 of the machine. j

It should further be noticed that the storage reservoir 154 communicates by a tube 155 with the tube 26. Therefore, this same air, is injected through the passage 14 during the next return stroke..

When the piston 14 passes before the opening 31,v the valve 32 falls back on to its seat owing to the setting of the cam 36.

vThe air remaining in the cylinder space is then strongly compressed. i Oil injection takes place at the end of the stroke. The injection needle 130 is raised at the end of the stroke when its head 131 comes into contact with the fixed vadjustable stop 132. The injection device, which is of any commei-cial type, causes the atomization and `projection of the combustible oil into the cylinder 11; where combustion takes place due to the heat of compression.

It should be noted thaty on arriving at the end of its stroke the cylinder 11 is braked strongly by the work of compressing the air. The inertia of the piston 42 tends to cause it to continue moving in the direction of the arrow 151, and, as the roller 35 is bearing on the rectilinear vportion of Vthe `cam 36, said piston is able to pass underl the projection 16 and to take up the position shown in 4ig. 2. y

The devices for. auxiliary rotation and security against shocks have been vsufficiently explained previously and it would be superfluous to 4dwell now on their mode of operation.

Operation. The foregoing expl nations have disclosed the normal operation of the motor compressor unit, In practice, .in view ofthe complete liberty left to the movements of the cylinder 11 and the piston 14 it has to be considered what would happen in case something arose to disturb the operation of the apparatus.

lit must tirst be remarked that, in the forof me. eenzaam maar,

ward stroke (direction of the arrow 150 formed partially into kinetic energy of the f oscillating parts, is found again lin the end under three forms: work of compression, work of discharge into the reservoir 54, work stored up in the buffer.

A similar balance for the return stroke (direction 151 for the cylinder 11 and 150 for the piston 14) shows that the work4 of expansion of the buffer should be equal,l or very nearly so, to the work of storage and compression preliminary tothe combustion.

lf any accidental cause should arise to upset these balances the piston 14 and the cylinder 11 will perform abnormal strokes, Whose amplitude and frequency will lbe different from. those provided for in the calculationof the apparatus.

' far described, is unstable.

' cord to return to its equilibrium,

voir 25 accidental increase in the force generated.

for will compress Athe buffer at the end of lts stroke with a pressure higher than the.

compression pressure, that is to say, higher than that in the reservoir 54.

First ret-urn stroke: Thel piston will bev returned towards the cylinder head 12 by a too powerful butter: at the end of its stroke it will impart an exaggerated comthe The combustion' thus pression to still more powerful than its produced will be predecessor, etc.

lf the effects of a sudden and accidental decrease in the force generated by the combustion are studied, the following conclusionswill be arrived at.

First forward stroke: lThe piston 13 will vnot have received sufficient energy to discharge from the cylinder 11.into the reser- 54 the expected quantity of compressed air. At the end of its stroke there will remain therefore an air butter which will have, it is true, the pressurein the reservoir 54, lout'whose volume will be greater than the volume expected. v

'First return stroke: The piston 14 is returned by the buier towards the cylinder head 12, receiving during this stroke an exaggerated impulse owing to the volume of air in the'buifcr having been increased while its pressure has remained equal to that in the reservoir 54. At the end of its stroke the I piston will compress the air for combustion to too great a pressure.

Itis seen therefore that the consequences fa diminution in the force of the combus- .tion`are`, by the end of an oscillation exactly the same as those due to an increase in such force.

The above given explanations have shown that the' operation of the apparatus, as so In other words, and to lsum up, if any disturbing cause shouldarise to upset the normal operation of the oscillating system, even if this cause should immediat-ely disappear, said .oscillating system would not tend of its own accontrary would tend to depart from it more and more.

The stabilization devlce which has been" Adescribed is intended to remedy this drawl back. It will now .be explained how -it works, supposinga sudden and accidental increase in. the

shouldl take place. The case of a diminution in Ysuch force need not be considered,

' as. it results, in the following oscillation', in

an vincrease ofthe preliminary and,na1l y, 1n an' increase 1n the combustion.

but on `the j .ably chosen,

force of. the combustion the force of'.

, openings 114 are in registry with the ports Suppose that the piston has been driven expansion of burnt gases arising from an abnormally strongcombustlon.

The piston 14 and the cylinder 11v will, to a in .the direction ofthe a1row`,151 and the -f cylinder in that ofthe arrow 150 by the certain extent pass beyond the position corresponding totheir theoretical dead points.

the Abuier rcompressed between as already explained, fat a than that in they reservoir Consequently, them; will be, greater pressure 54 air exceeds the normal compression pressure, the valve 110 (Fig: 5) lifts, and puts the dead space of the cylinder 11 .into communication with the vauxiliary reservoir 107. This latter is absolutely isolated at this moment from the exterior, as the lever 97 occupies the position shown in Figure 5, and the orifice 114 is not oppositel the orifice 113.

Under these circumstances, the oscillating parts absorb the excess -of kinetic energy, not through the work of compression of the buer comprised in the cylinder 11, but through a work of compression acting both on the air in said cylinder and on that in the auxiliary reservoir 107.

When the movement of the oscillating system 'stops andireverses, the non-return l3nt `when the pressure of the compressed butler which,l on expansion, can act on the piston and cylinder is that remaining in the cylinder 11 `between the cylinder head 12 atthe moment when the valve 11() has favflen back on its seat.

The piston 14 form therefore their return stroke under the impulse of a buffer of lesser massv than the normal buffer, but whose pressure, is on the other hand, superior to the normal. It` is easy to imagine that the'expansion of such a butter may be equivalent to that of the theoretical buffer and that consequently, the operations of the return stroke 'can be correctly performed.

As a matter of fact, a detailed calculation shows that, as a general rule, the deadening of the' abnormal oscillation'and the return to the theoretical operation are not achieved in one single stroke, but, if the capacity of .the auxiliary `reservoir 107 has been suitas a function of the normal volume of the. dead space,

apparatus is corrected in a small number of oscillations. v

It should be noted that during the return stroke of thevv piston 14 and the cylinder 11,

the lever 97 swins in the direction of they arrow 151 under necting rod 94.

he influence ofthe conthe piston 14 andI and the cylinder 11 per-v stability of open. vation of the apparatusis obtained: lany dis- "t'urbance in 'the normal operation of the- At. a given moment the 113. Communication is thus established between the auxiliary Areservoir 107 and the reservoir 54 by means of the passages 135,

112 and 115. `In this Way the pressure lofl the air contained in the reservoir 107 is automatically brought back 'to the compression pressure which is also, it must not be yforgotten, -thatvof the normal buffer. The de- ,vice is thus ready to Work again normally,

-cylinder, and a free piston reciprocating in said cylinder, said cylinder being mechanically free to reciprocate With respect to said frame, means for injectinginto said cylinder a combustible oil under pressure, said means consistingin an injection 'needle valve mounted on the cylinder head, a stop on said needle, a fixed abutment cooperating with said stop, and means l:for adjusting the position of said abutment..

3. In an apparatus comprising a cylinder and a free piston reciprocating in said cylinder, one end portion of the cylinder serving as a combustion chamber, the combination of means for permltting the escape of I" burned gases after they have expanded down to a pressure approximately that of thev surrounding atmosphere, means for admitting from the atmosphere a certain quantity of pure air which enters'the cylinder in the proximity of the combustion chamber and is drawn along in the Wake of the burned mees-,eso

gases, means cooperating with the piston and cylinder for compressing and dlscharging out of the cylinder a partof the pure air it contains, the air thus discharged being evacuated into a storing reservoir at a low pressure, the contents of the reservoir being utilized to produce the aforesaid scavengmg at a lowxpressure,the air remaining in the cylinder being compressed by the piston, and means for injecting into thecombustion chamber and burning oil under pressure2 and other means cooperating `with the piston and the other end portion lof the cylinder for storing energy developed by the moving piston. v l

4. In au apparatus comprising a cylinder and a free piston reciprocating in said cylinder, one end portion of the cylinder serving as a combustion chamber, 'the combination of means for permitting the escape of burned gases 'after they have expanded down to a pressure approximately that of the surrounding atmosphere, means for` admitting from the atmosphere a certain quantity of'pure air which enters the cylinder in the lproximity of the combustion chamber and is drawn along in the Wake of the burned gases, means cooperating with the piston and cylinder for compressing and dlscharg- 'ing out of the cylinder a part of the pure air it contains, the air thus discharged being evacuated into a storing reservoir at a low pressure, the contents of the reservoir being utilized to producethe aforesaid scavenging at a. loW pressure, the air remaining in the cylinder being compressed by the piston, and means for injecting into the combustion chamber and burning `oil under pressure, and other means cooperating with the iston and the other end portion of the cy inder for admitting, compressing and discharging all'.

y RAUL PATERAS PESCARA.

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