US1612494A - Internal-combustion engine - Google Patents

Description

'55 phere into the Patented Dec. ze; 1926.

4manen STATES PATENT oFFicE.

HENRY H. CUTLER, OF BBOOKLIE'E, MASSACHUSETTS.

INTERNAL-continuaron ENGINE.

Application 'lred November 4, 11924.' Serial No.l 747,746.

Myinvention relates to internal combustion enginesl and more especially to suchengines 'of the variable clearance type inwhich "means are provided fory varying the clear- 5 ance space in unison with themovement of,

the4 power piston, whereby the volume of such clearance space is made to vary 1n such close relation to the load on the engine that I the degree of. compression may be mainl111 tained approximately constant at all loads.

A further object, of my invention is to -utili'zethe same mechanismV for mechani- -'cally scavenging the cylinder .after every explosion, and a still more important object l?? ofv my invention is to provide a very 'large amount of resilient recoil at the time of each explosion of the working `mixture in the' enginecylinder whereby the ystrain vupon the crank shaft and the reciprocatingparts is reduced to from one-half'to one-third of the v vnormal'initial pressure thusfmaking it praca tical to employ a compression pressure twice as high as possible in the 'usual form of combustion engine, without producingknocking or destructive wear.

The pr sent invention isa further devel- 'opmento that disclosed in my pending application Serial No. 701,051, filed March'22,

The principall feature of-m-yy invention is the provision of an air reservoir'from which the. air cannot -escape/during the operation V of the engine, and the still further utiliza-- tion ofthe same mechanism for automatically supplying to thesaid airvreservoir, air compressed to any pressure desired under the control of the operator, said compressed air being utilized to control the resulting and correspondingdegree of compression in the engine cylinders.

Figure 1 is a central vertical section of one of the cylinders of an internal combustion cnginc,embodying my invention and showphragm pressurev regulator, controlled by a.'

rod extending to the instrument board under thecontrol of the operator; A

Fig. 3 is a horizontal section taken on the line 3-3 of the pressure regulator showing the means for admitting airfrom 'the atmos-y space 77 'of the engine cylinder.; f f

. or volume of each cylinder 18 between each ing the relative position of the moving arts consisting ofthe casting 17 secured by bolts 17 to the'top yof the cylinder block 14 in the 0 usuall manner. In the casting 17, cylinders 18, etc., are formed and constitute extensions of the corresponding cylinders ofthe main engine block 14. Midway in each of these cylinder extensions is a fixed head or plug 05 22, each head being hollow and connected with' the water-jacket by passageways 26, 26. It is essential, that these fixed heads 22 shall make a gas and water-tight joint with the walls of the cylinder in which they are placed. This result I obtain by accurately grinding the heads 22 a few thousandths of an inch larger in diameter than the bore of the Icylinder extensions 18, then heating the entire cylinder casting 17 and placing the 'heads 22 therein cold, so that when the cylinder casting 17 cools, the heads 22 are firmly f gripped; This process I have found in practice to be sutlicient not only to make a perfect water and gas-'tight joint, but. alsoto stand the pressure of the exploded gases under Working conditions.

ArrangedV for longitudinal movement in ea'ch cylinder 18 is a member 28, the portion power piston 32 and said movable member 28 forming a compression .chamber 75,' and means areprovided for automatically con-- trolling the position of said movable member 28 so as to vary the volume of said compression chamber 75 in practically exact accordance with the variation of the load on the engine, thus keeping. the degree of compression. approximately the same at all times. Theposition of said movable member 28 is controlled automatically and resiliently for the 'purpose above specified and after each explosion of the Working mixture the position of said movable member 28 is automatically changed so as to greatly enlarge the volume of the compression'chamber 75, andthereby greatly reduce the resulting pressure of the exploding gases upon the crank shaft and reciprocating parts of the engine. At the completion of the power stroke' the movable member 28 has been automatically moved towards the power piston 32 and smoothly brought to a stop in such position as to etect almost complete mechanical scavenging ofthe engine cylinder on-the completion of the exhaust stroke of the power piston 32, as shown in Fig. 1,

the top part 37 of each cylinder extension 18- is another movable member or dash-pot piston 39. Each dash-pot or pressure piston 39 is connected with its respective scavenging piston 28 by means of a long rod 40. Said rod is preferably made of hardened steel and Works up and down in a long bushing 40 made preferably ot' bronze bearing metal in which bushing 40' the steel rod 40 makes a free but close fit that is nearly, if not entirely, airtight. The lower end of said rod 4() has a head 41 and is held to the scavenging piston 28 by means of a Washer 42 riveted to the bottom of the piston 28 with rivets 43. In the bottom of the rod 40 is shown a cylinder 45 arranged to slide freely in a hole in the rod 40 and pressed upby a spring 46. yl`he lower end of the cylinder 45 terminates in a rod 47 to Which is riveted a conical valve 48 after the rod/40 has been attached to the piston 28 so as to form a small valve free to open into the space75 whenever the pressure in the compression chamber 76 exceeds the pressure in the chamber 7 5;

The pressure piston 39 also contains one or more small valves 50 held down by a. spring 51 seating on the inside of the piston 39 and free to open whenever the pressure in the chamber 77 (formed between the bottom of the pressure piston 39 and the top of the head 22) exceeds to apredetermined degree the pressure in the air reservoir or chamber 78 above the pressure piston 39.` Inserted in a circular chamber turned out in the top of theplughead 22 is a, coil of insulated Wire 53. The inside terminal of this Wire coil is welded to athin brass tube 54a made to tit. closely over the central pole .54 of the circular electromagnet formed in the end of the plug-head 22. The outside terminal 53a of the coil 53 passes through a hole drilled in the plug head 22 and then through a threaded hole 55 drilled through the cylinder 37 opposite the hole in the head 22. A threaded bushing 56 of tough insulating material is screwed up solid against some asbestos thread packing surrounding said terminal 53a where it passes through the holes drilled in the plug 22 and cylinder l37, thereby forming a permanent airtight packing around said .terminalwire of the coil 53. A brass disc 58 is pressed down against shoulders cut in the inside and outside poles of. the electro.-

P- magnet so as to make a ractically airtight tit.' The depth of said s ioulders is preferably such that the top surface of the brass plate 58, when in position. will be about onehundredth of an inchlower than the surface of the inside magnet pole v54 so that when the pressure piston 39 makes mechanical contact` with said central pole 54. a minute air chamber 77 is formed between the bottom of said piston 39 and said brass plate 58.. The size of said minute air chamber 77 of reiaeae course will depend upon the size of the engine, but for an engine having a bore of 33/4, the size of chamber 77, above mentioned, would be approximately correct.

The pressure piston 89 is preferably made of a non-magnetic material such as phosphor bronze, and is provided With a steel disc 39 mounted on the bottom of the piston 39, as clearl shown in Fig. 1.

Be ore the final assembling is made of the above mentioned parts, and before the plug 22 is shrunk into the casting 17 as previously explained. the steel rod 40 is passed through the bushing 40 in the plug 22 and 'the pistons 28 and 39 are clamped firmly together' by means of the nut 44 in the position shown in Fig. 1. rl`he steel plate 39 is then ground against the central pole 54 of the electromagnet so as to make an airtight valve for the purpose-of preventing any possible escape of air from the reservoir 7 8 by the outside of the piston 39 underV the Steel plate 39 and around the long rod 40 inside the bushing 40. This arrangement is an essential feature of my invention as any appreciable escape of air from the reservoir 78 during the operation` of the engine would constitute an impractical and uncommercial device.

The above mentioned parts are then permanently assembled as shown in Fig. 1 andthe cover-plate 6l electric welded to the casting 17, `as shown, thereby making an absolutely airtight joint. A cap 63 is shown threaded into the head 67 to afford access to the interior thereof for adjusting the springs 51 when desired.

Screwed into the side of each cylinder 18 above the plug 22 is :1n-automatic air valve casing 91 containing a valve 92 held to its seat by a spring 93 and arranged to open inwardly whenever the pressure in the chamber 77 (formed between the bottom of the. y.

piston 39 and the brass plate 58) falls below that of the outside atmosphere.

The valve casing 91 is shown connected by a rubber tube 9G with the outlet opening 112 of the diaphragm controlled regulator.

This pressure regulator, Fig. 2. is shown mounted on two projecting lugs 101 and 10.2 cast on the cover 61. The lug 101 has a circular opening on-the side covered by a metallic disc 1.03 permanently welded to it so as to forni an airtight joint. The inside of the disc 103 is subjected to the. pressure of the air in the reservoir 7 8 by means of the hole 104 drilled'as shown through the cover 61.

A disc 105 is pressed against the outside ot the diaphragm 103 by means ot an adjustable spring'106. The strength of the spring 100 may be adjusted by screwing th` threaded Wheel 107 on the threaded spindle 108, which spindle is shown fastened to the lug 102 by the screws 109. The wheel 107 reo has teeth cut so as to mesh with teeth lcut in the rod 110 which is designed to pass over the engine to the instrument board where it may be reached and turned handily by the operator. inside the-spindle 108 is shown a long rod 111 having one end in the form of a conical valve arranged to close the valve seat 112 and thereby shut offthe opening 112. The other end of the rod 111 seats in the disc 105. Another rubber tube 113 connects the opening 112 with'an air filter (not shown) used preferably in connection with the carburetor to filter all the air used either in the' engine proper or supplied to the air reservoir 78. Back of the valve seat 112 is drilled a hole 114 (Eig. 3) and central with this hole 114 is shown a threaded nipple 115 screwed into the-main' casting 102. rlhis nipple 115 is shown surrounded by one end of the rubber tube 96 the other end of said rubber tube-96 being connected, as shown in Fig.l `1.,.to the valve casingA 92. Whenever the 'pressure 'of the air' against the dia phragm 103 isinsuiiicient to keep the valve 111 pressed against its seat 112, air is free to be drawn into the space ,'77 by way of the opening 112', passage 114 and rubber tube 96. Each cylinder of a multipler cylinder engine is preferably equipped with an automatic intake air valve 91 which is connected by rubber tubing 96 or any .other convenient way to one diaphragm regulator, Fig. 2, so

v that when the pressureot' the air in the -lll reservoir 78 is suliicient to force the disc 105 from its seat and close the valve seat 112, no more air will be pump'edlinto the reservoir 78. v

The operation of the engine is as follows:

The engine is started by first closing the circuit to the electromagnet coils 53 by means 'of the rheostat lever 72 andthen turning over the engine either by. hand or with a small electric motor in the usual manner. the power piston 32 approaches the scavenging piston 28, sutlicient compression is developed to force the pressure piston 39 away vfrom its seat against the pull y of the eleetl'omagnet 53 which is preferably kept constantly energized. The piston 39 being thus released from thev electromagnet allows both pistons 28 and 39 to move sud denly up' and away from the power piston :E8 until this movement is stopped by the compression of the air in the chamber 76.- 'lhe minute amount ol air in the-.chamber 77 formed between the bottom of the prei:- sure piston 39 and the brassplate 58 immediately expands to a pressurefar below that ot' the outside atmos here causing the air valve 92 to open an -admit fresh'` air into the chamber 77. .The power piston 32 then descends, being foreed'down by three dillerent sources of power.

First. The compression of the air 1n the chamber 7 6,' Second. The difference between atmospheric pressure above the pressure piston 39 and less than atmospheric pressure below the piston 39. Third. The driving power of the electric motor starter.

The pressure piston39 new approaches its seat against the central pole 5st of the electromagnet. ln sodoing the air which has been sucked in through the air valve 92 is compressed in the now minute air chamber 77 acting as a cushion y.against the pull 'of the magnet which finally pulls thev piston 39 against the central port 541of the electronlagnet. This process is repeated until 'finally so much air has been sucked in through theair valve 92 that it becomes sufficiently compressedto open the valves and thus the engine begins to force air into the reservoir 78. By this time theengin-e will probably have started, operating under a compression pressure in excess of twenty pounds. This compressure pressure is the sum ofthe difference in-air pressure above and below the piston 39 and the air compressed in the chamber 76, and can be increased or diminished in accordance with the size determined upon of the chamber 76. The engine can now be brought up to speed and air will then be rapidly forced into the reservoir 78 untilsullicient ressure has been developed in said reservoir 78 to force the disc 105 Jfrom its seat and thus shut olf communication with the atmosphere by means of the valve 111 so that no more Ire'sh air can be pumped into the reservoir a 8.

It is evident that the electromagnet-is not called upon to exert suliicient power to compress air at atmospheric pressure to the pressure in the reservoir 78, but merely hasy to exertsullicient pulling power to overcome the difference in air pressure between the top and bottom of the piston 3 9 sufficient only to overcome the pressure of the springs 5l which hold down the 1ittle.-valves 50 upon their seats. 'The strength of these springs 51 is sufficient to cause an increase of air pressure'in the chamber 7 7, great enough to 'act as a cushion to prevent the piston 39 from hammering against its seat 54 of the electromagnet. This tendency ot the pistons 39 to hammer against the central polo 54 ot' the electromagnets is further subject to perfect control by means of the rheostat -69 so that the en'gine will run quietly and the valve lll to open and the engine will then automatically begin to supply additional Keeping the electromagnets energized continuously during 'the operation of the engine not only does away with extra eircuit controlling devices, but also possesses another very decided advantage, namely, the pistons 28 and 39 possess more or less weight and a very large moment ol inertia, especially when the engine is operated at high speed, by keeping the electromagnets permanently energized, the pistons 28 and 39 start to move quickly the moment they are released from the electromagnet, and this is followed by the tiring of the mixture so shortly atter- Wards that the pistons 28 and 39 do not have time to stop their upward motion. The vlriclr of the explosion against the crank shalt is thus still further reduced because it is not called upon to immediately start tol move the weght of the pist- ons 28 and 39 from a position of rest.

By the addition of practically one moving part, namely, the pistons 28 and 39 rigidly connected by the rod 40, this part performs no less than tive ditlerent uses, First, it automatically supplies compressed air to any desired pressure for the reservoir 78, thereby determining the compression pressure of the engine. Second, it thoroughly scavenges the engine of the inert exhaust gases usually lett over in the engine cylinder at the completion ot the exhaust stroke. Third, it provides a very large amount of resilient recoil at\ the instant o each and every explosion ot the working mixture thereby greatly diminishing the resulting mechanical strains upon the engine mechanism and correspondingly increasing 'the life of its vital parts. Fourth, it greatly increases the economy of the engine by making it practical to use very high compression pressures. Fifth, it still Afurther increases the economy7 of the engine by maintaining a high compression with a reduced volume when operating under lighter loads than full load.

I claim-.-

, 1. Aninternal combustion engine com-4 rising in combination a cylinder, a hermetically vsealedcylindrical chamber secured to and forming an extension et" said cylinder, a piston reciprocable in and closely fitting Said chamber, an automatic air intake valve and means whereby thereciprocating action of said piston will draw air into said sealed chamber until said air has been compressed in said sealed chamber to any pressure desired by the operator.

2. An internal combustion engine com-v4 rising in combination a c linder, a hermetvlcally sealed cylindrical c amber secured to reiaeeej and forming an extension ot said cylinder, a piston of non-magnetic material, a disc ot magnetic material attached to said piston and of smaller diameter than said piston, and magnetic means for 4forcing back into the inward portion of said hermetically sealed chamber, gaseous leakage around said piston.

3. An internal combustion engine comprising in combination a cylinder, `a hermetically sealedv cylindrical chamber secured to and 'forming an extension ot said cylinder, an air intake valve, a piston einen-magnetic material reciprocable in and closely fitting said cylindrical chamber, a disc ,ot magnetic material attached to and, preterably of smaller diameter than said piston, and magnetic means whereby the air that is drawn in by the action ot the engine when running is forced into said hermetically sealed chamber until any pressure /desired is obtained. i

il. An internal combustion engine 'comprising in combination a cylinder, a hermetically sealed cylindrical chamber `securedto and forming an extension otsaid cylinder, a piston closely tting 'said cylindrical chamber and reciprocable therein, an air valve so located 'that the outward motion et said piston during the operation of the engine will tend to draw air in underneath said piston, andan air conduit connected to a pressure regulator, which will automatically.- shut ed' the'supply of air when said air 'has been compressed in said sealed chamber to `the desired degree.

5. An internal ,combustion engine comprising in, combination a cylinder, atixed head intermediate the ends of said cylinder,

a power piston in said cylinder on one side oft said head, a' scavenging piston located between said head and said power piston, a dash-pot piston on 'the other side of said head, a rod passing through said head and rigidly 'connecting said scavenging and dash-potpistons, a hermetically sealedcylindrical chamber forming an extension oit said cylinder, said dash-'pot piston being reciprocable in and closelyitting said chamber, an automatic intalre valve so located that the reciprocating motion of said dashpot piston during the operation of the engne will cause fresh air to be drawn: in

ythrough said air valve underneath rsaid dashpot piston, and magnetic means fcrftorcing said fresh air tothe other side of said. dashpot .piston into said sealed chamber until any desired degree of compression is ob-y tained. l

iin testimony whereof, l have hereunto subscribed my name this 3rd day ot November,

HENRY H. CUTLER.

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