US1338056A

US1338056A - Eugiwe

Info

Publication number: US1338056A
Authority: US
Publication date: 1920-04-27
Anticipated expiration: 1937-04-27

Description

F. S. WAHL.

INTERNAL COMBUSTlON ENGINE.

APPLICATION FILED NOV-30, 1911.

1,338,056. Patented Apr. 27, 1920.

4 SHEETSSHEET I.

F. S. WAHL.

INTERNAL COMBUSTION ENGINE.

APPLICATION FILED NOV-30.1917.

1,338,056, Patented Apr. 27, 1920.

4 SHEETS-SHEET 2. 5/

my. Z. i z

F S. WAHL.

INTERNAL COMBUSTION ENGINE.

APPLICATION FILED NOV-30,1917.

1,338,056, Patented Apr. 27, 1920.

4 SHEETS-SIIEET 3.

F. S. WAHL.

INTERNAL COMBUSTION ENGINE.

APPLICATION FILED NOV-30,1917.

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FRANK S, WAHL, OF NORTH TONAWANDA, NEW YORK.

INTERNAL-CGMBUSTIGN ENGINE.

Specification of Letters Patent.

Patented A nea 1920.

Application filed November 30, 1917. Serial No. 204,571.

To all whom it may concern Be it known that I, FRANK S. Warm, a citizen of the United States, residing in North Tonawanda, in the county of Niagara and State of New York, lave invented new and useful Improvements in Internal-Combustion Engines, of which the following is a specification.

This invention relates to internal combustion engines and more particularly to an engine of this type which works on the twostrolre cycle principle.

Internal combustion engines which are now most generally in use may be divided into two classes, one known as the twocycle or two-stroke cycle and the other known as the four-cycle or four-stroke.

Other things being equal, a two-cycle engine should develop twice as much power as a four-cycle engine inasmuch as the 1m pulses of a two-cycle engine are tw to that of a four-cycle engine, which, however, has not been the case in actual practice.

Furthermore, most forms of two-cycle engines now on the market utilize the crank case as a fuel. reservoir which is undesirable, because leakage is practically unpreventable and it also renders impossible the use of the splash-system of oiling. The possibil ty of pro-ignition of the compressed gases n the crank case of two-cycle gas engines is an other objectionable feature.

l he principal objection to the four-cycle engine is that thesame requires a reducing gearing for driving cam she ft from the main shaft which adds unnecessary weight, complicates the mechanism and increases the cost of manufacture and maintenance.

From the foregoing analysis of these two tvpcs of engines, it has been found that a two-cycle engine will deliver from one and one-third to one and one-half of the amount of power developed by a four-cycle engine for a given amount of fuel consumption.

It is the object of this invention to produce engine of the two-cycle type which retains the advantages of he two-cycle and the four-cycle types of engines and eliminates the objectionable features of both, and to accomplish this in manner which will permit of handling a larger volume of the gaseous mixture than the normal piston displacement, to pass this mixture through large ports and passages under sitotable 1 ressure so that the supply-0; fuel til-e engine is effected promptly, to lengthen the interval of-time during which the inlet port is open so as to permit the maximimi inflow of the mixture, and to produ;e a thorough scavenging of the cylinder so as to obtain the maximum power efficiency from the fuel consumed.

My invention has the further object to so organize the means whirh transmit the power to the crank shaft that the impulse due to the explosion of the gaseous mixture is applied simultaneously to diametricallyopposite sides of the crank shaft, thereby avoiding hammer-blows on the shaft and the parts associated therewith and also avoiding undue wearing of the bearings in which this shaft is journaled.

Another purpose of my invention is to provide means whereby a greater volume of gaseous mixture is admitted to the cylinder than the ordinary piston displarement usually affords and to maintain the compression of this mixture in the cylinder constant under varying atmospheric conditions by means which are controlled either manually, thermostatically or barometrically, or by a suitable combination of such controlling means. This last-mentioned provision is particularly suitable for aeroplane engines inasmuch as engines for this service must travel in and utilize the atmosphere not only at sea level but also thousands of feet higher where the density of the air is much lower which renders the engine compression variable at different levels and therefore yields variable power. An engine utilizing a fixed piston displacement is incapable of so filling the cylinder as to compensate for the varying densities of the atmosphere. By hanling greater volume of the gaseous mixture than the normal piston displacement, contemplated in the present invention, together with the regulator for adjusting the fuel intake to compensate for variation in atmospheric conditions, it is possible to maintain the compression of the mixture constant.

In the accompanying drawings: Figure 1 is a vertical section of one form of internal parts when the explosive mixture has reaqhed the limit of its expansion and is exhausting from the working cylinder. Figs. 3, 4i, and 5 are horizontal sections taken in the correspondin ly numbered lines in Fig. 1.. Fig. 6 is a fragmentary vertical se-tion, on an enlarged scale, of the controlling device which operates to hold the main inlet valve open at the end of the working stroke and the beginning of the compression stroke of the piston. Fig. 7 is a fragmentary vertical section taken on line 7--7, Fig. 5. Fig. 8 is a vertical section showing a modification of my invention.

Similar characters of reference refer to like parts throughout the several views.

Referring to Figs. 17, 1 represents the hollow base or frame of the gas or internal combustion engine which may be operated by any explosive medium such as gas, gasolene or kerosene. Within this base is arranged a main or driving shaft 2 which in this instance is arranged horizontally and. journaled in

bearings

3, 3 on the bottom of this base, or in any other. suitable manner. Between its bearings this shaft is provided with a central crank 4; which projects from one side of the center of the same and two

side cranks

5, 5 which project laterally from the axis of the shaft diametrically opposite to the central crank, this last-mentioned crank being arranged midway between the two side cranks.

6 represents an upright tubular guide whi h is mounted at its lower end on the upper part ofthe engine base or frame and 7 an upright pump cylinder arranged above the tubular guide and axially in line therewith and having an internal bore than the bore of the tubular guide. About midway of its height this tubular guide is provided with anexhaust passage or inanifold 8 which is preferably of annular form and opens inwardly to the bore of this guide and is provided with an outlet 9 on its outer side, as'shown in Fig. 4:, whereby the products of combustion may be discharged to the atmosphere or conducted to any other suitable place. For the purpose of cooling the engine, the tubular guide and the pump cylinder are provided with an inclosing shell 10 which forms a jacket 11 therebetween through which water or other cooling medium is circulated in a manner similar to that commonly practised in engines now cates lengthwise within the tubular guide and. forms part of the means whereby the gaseous fuel or combustible mixture for operating the engine is drawn into the engine and compressed therein and also part of the means whereby the power to the exploding mixture is transmitted to the crank shaft. 'At'its lower end this tubular member is ar ranged within the base connected on diametrically opposite sides by means of two connecting rods 13 with the side cranks of the main shaft, as shown in Figs. 1 and 2. At its upper end this tubular member is connected with a plunger or piston 14 which reciprocates vertically within the pump cylinder or barrel and forms part of the mixture pumping and compressing mechanism. The lower end of the tubular member 12 is open and its upper end is provided with means for feeding the explosive charge into the same and also igniting this charge. Between its upper and lower end this member is provided with an exhaust or outlet for the products of combustion from the interior of this member into the exhaust manifold, this exhaust of the tubular member being preferably constructed in the form of an annular row of comparatively narrow slots or openings 15. 16 represents the power or firing piston reciprocating lengthwise within the tubular member and connected with the tral crank of the main shaft by means pitman or connecting rod 17. The tul'nilar member thus serves as the firing cylinder of the engine; the guide rod of thepump plunger also serves to deliver halfof the power developed to the crank shaft; and the same also operates in conjunction with the firing piston and the exhaust manifold as the outlet valve mechanism, whereby the exhaust or outlet of the engine for the spent products of combustion iscontrolled.

The space in the pump cylinder above the pump plunger and the space within the upper part of the tubular member between the pump plunger and the firing piston, which last-mentioned space forms the engine cylinder proper, are adapted to be placed. in communication or cut off from communication by a valve mechanism which may be variously constructed. The valve mechanism which is shown in Figs. 1 and 9,, is an example of one which may be used for this purpose and as there shown the same comprises valve casing or cage 18 which is secured by means of a screw joint in a vertical opening formed centrally in the pump plunger and the top of the cylinder, and provided centrally with a port 19 leading from the upper part of the pump cylinder to the upper part of the firing cylinder and terminating at its lower end. in a downwardly-facing conical main valve seat 20. 21 represents an outwardly-closing main intake valve of conical form adapted to engage he valve seat 20 and provided with an upwardly-projecting valve stem 22 which is guided in an upright guide sleeve 23 which is connected by a bridge 2% forming part of the valve cage 18. The main intake valve is yieldingly held in its closed position by means of a spring 25 surrounding the valve stem 22 and bearing at its lower end against prolonging the period during which this valve is held open and therefore insuring a maximum fuel charge for the machine. In the form of this controlling device which is shown in Figs. 1, 2 and 6, the same com-- prises an upright cylinder 27 which is mounted on the upper head of the pump cylinder and has the lower end of its interior communicating with the upper end of the pump cylinder, a controlling piston 28 moving vertically in this cylinder, an upright shifting rod 29 secured to the controlling piston and having its lower end guided in a bridge 30 on the lower part of this cylinder} and arranged vertically in line with the stem of the intake valve while the upper end of this rod is guided in a screw nut or bushing 31 secured to the top of this cylinder, a spring 32 surrounding the upper part of this rod and bearing at its lower end against the top of this piston while its upper end bears against said screw nut and a vent opening 33 arranged in the upper part of the controlling cylinder and placing the upper end of the same in communication with the atmosphere. A

On one side of the lower part of the pump cylinder, the same is provided with a lateral extension 34cwhich contains a supply section 35 of a fuel supply conduit or passage which communicates with a carbureter or any other source of supply from which the explosive mixture is drawn and two

delivery sections

36, 37 one of which 36 opens into the upper end of the pump cylinder and the one 3'? opening by a lower branch passage 38 into th lower end of this cylinder and by an upper branch passage or port 39 into this cylinder at a place between its upper and lower Between the supply conduit section 35 and the delivery conduit section 36 is arranged an inwardly facing valve seat 39 and between the supply conduit sec tion 35 and the delivery conduit section 37 is arranged an inwardly facing valve seat 40. 41, 4-2, represent two inwardly-opening puppet valves which are adapted to engage with the valve-

seats

39, 40, respectively, and are guided in their movements by means of upright valve stems 43, 4A projecting downwardly, respectively, from the undersides of these valves and guidedin tubular ways 45, 46 on the adjacent lower part of the extension 34, as shown in Figs. 1, 2- and 7.

Any suitable means may be provided for igniting the combustible charge within the firing cylinder at the proper time, those shown in Figs. 1 and 2 being typical forms of spark plug which is suitable and comprises a tubular bushing 47 secured in an opening extending vertically through the pump piston and the upper head of the firing cylinder and electrically connected through the metallic parts of the engine with one side of an electric source so that the side points 48 on the inner ends of this plug form one terminal of the circuit, and a central terminal 49 which is electrically connected with the other side of electric source, and an insulating core 50 supporting the central terminal on said bushing. Inasmuch as this spark plug reciprocates with the firing cylinder and pump plunger an extensible connection is provided between the central terminal and the electric circuit, this being preferably accomplished by means of a spring or flexible conductor 51 connected at its lower end with the upper end of the central terminal 49 while its upper end is connected with a binding post 52 fixedly mounted on the upper end of a. tubular cap 53 which is constructed of insulating material and mounted on the upper head of the pump cylinder, as shown in r igs. l and 2.

When the parts of the engine are in the position shown in Fig. 1, the firing or working piston is in its uppermost position, the firing cylinder and plunger are in their lowermost position, the controlling piston is in its lowermost position, the main intake valve and the check valves are closed and the exhaust ports of the firing cylinder are arranged below the firing piston and the exhaust manifold. normal operation of the engine, a charge of gaseous fuel or mixture is compressed between the firing piston and the upper part of the firing cylinder and a partially compressed charge of fuel is contained in the 7 upper part of, the pump cylinder. Upon now igniting the charge of explosive mixture in the firing cylinder the latter together with the pump plunger will be raised and the firing piston will be depressed and a pressure is exerted against the main intake valve which aids in holding the same shut. During this movement of the pump plunger and firing cylinder and piston the cranks of the main shaft operate on diametrically opposite sides of the latter and the same is turned with a working impulse without however sustaining any shock or undue lateral pressure.

Immediately after the pump plunger has effected the initial part of its upward movement in the pump cylinder this, plunger closes the upper branch passage 39 and produces a suction through the lower branch passage 38 into the lower end of the pump At this time, during the cylinder so thatthe check valve 42 is opened and; a portion. ofv the gaseous mixture is drawn from the. carbureter into the lower end of the pump cylinder. After the pump plunger has passed above the upper branch passage 89 part of the gaseous mixture is drawn through. both the lower and

upper branch passages

38, 39 into the lower end of the cylinder until the plunger reaches the upper. endof its stroke, as shown in Fig. 2. During the subsequent downward movement of the plunger the check valve 42 is closed and the gaseous mixture within the lower part of the cylinder is compressed until the pump plunger passes below and uncovers the. upper branch passage 39 at which timethe compressed charge or mixture=passes from the lower end of the pump.

cylinder through the lower and

upper branch passages

38, 39 into the pump cylinder: abovethe plunger. During the down, ward movement of the plunger the same also draws an additional quantity of gaseousmixture past; the valve 41 and

passage sections

35, 36 into the upper end of the pump cylinder.v The two quantities of gas OIlErdI'iIWIldirectly into the upper part of. the pump cylinder during the downward movement of the latter and the other drawn indirectly into this end of the cylinder during the upward and downward stroke of the pump plunger are subsequently compressed in the upper part of the pump cylinder, during; the next following upward strokeof the pump plunger.

The pressure of the expanding burning mixture in the firing chamber is greater than the pressure of the gas mixture within the upper end of the pump cylinder, this being partly due to the fact that the latter is of larger cross sectional area than the firing cylinder. During the last part of the firing stroke of the engine during which the firing piston is in its lower position and the pumpplunger and firing cylinder in their upper position, the exhaust ports of the firing cylinder registers with the exhaust manifold and the firing piston uncovers these exhaust ports and is arranged below the same. The instant this occursthe prod nets of combustion of the burned mixture escape from. the lower end of the firing chamber through the exhaust ports thereof into the exhaust manifold. This causes the pressure in. the firing cylinder to drop immediately below that of the compressed gases Within the upper end of the pump cylinder whereby the predominating pressure of the fresh gases in the pump cylinder forces the intake valve to open and causes the live or fresh charge of gaseous fuel to pass downwardly into the firing cylinder. During this movement the fresh gases spread from thecentral upper part of the firing cylinder over the entire area Within the same and move downwardly in a compact mass which sweeps the spent gas downwardly before it and outthrough the ex haust ports so that no dead gas remains in the firing cylinder, thereby increasing the power and efliciency of the engine.

Immediately after the firing piston has, reached its lowermost position and the firing cylinder its uppermost position the. movement of these parts is reversed and during the initial part of the subsequent upward movement of the firing piston and the downward movement of the firing cylinder the exhaust portsare again closed by the firing piston. so that the fresh charge of the. explosive mixture within the firing cylinder is compressed during the remaining ortion of their compression strokes. W hen the firing cylinder and firing piston reach the end of their downward and upward strokes respectively, the compressed mixture between the same is ignited and the next cycle of operations is repeated as above described. The exhaust ports are. preferably comparatively narrow but together provide ample area to avoid any restriction or re sistanceto the free escape of the burnt gas and at the same time permit of again closing the exhaust in the shortest possible time.

The pressure of the mixture in the upper part of the pump cylinder during the upward stroke of the plunger is sufficient to raise the controlling piston in opposition with its spring 32 and during the last part of the upward movement of the pump plunger and firing cylinder, the upper end of the stem of the main intake valve engages with the lower end of the shifting rod of the controlling piston, as shown in Fig. 2. As the pressure in the upper end of the pump cylinder decreases by reason. of the intake valve at this time being open and permitting the mixture to pass from the pump cylinder into the firin cylinder the 110 pressure of the spring 32 prec ominates over the mixture pressure against the underside of the controlling piston, thereby causing this piston to follow the intake valve during the initial part of its downward movement 115 with the pump plunger and firing cylinder and hold this intake valve in its open position until the firing piston has closed the exhaust ports of the firing cylinder. After this initial downward movement of the fir- 12o ing cylinder, the controlling piston reaches the end of its downward movement in the controlling cylinder and permits the main intake valve to be closed by the pressure within the firing chamber and the action of 125 the intake valve spring 25 so that the fresh charge or mixture will be compressed with in the firing-cylinder during the balance of the compression strokes of this cylinder and 1ts companion piston. By this means a com- 130 plete and thorough scavenging of the firing cylinder is efi'ected and renders the fresh charge perfectly free from inert or spent gas, The formation of an air pocket in the upper end of the controlling cylinder is prevented by the'vent opening 33 which permits the air to freely enter and leave this end of this cylinder during the rising and falling movement of its piston.

When this engine is used for propelling an aeroplane the range of travel which varies anywhere from sea level to high altitudes, it is desirable to provide means for varying the admission of gaseous mixture to the engine in accordance with the changes in temperature of the engine and variations in the condition of atmosphere in which the aeroplane for the time being is traveling. These means are preferably associated with the check valves 41, 42 in the supply conduits and may be controlled either manually or thermostatically or barometrically. The means shown in connection with the check valve 41 in Fig. 7 are manually controlled and comprise a spring 55 surrounding the lower end of the valve stem 43 and bearing at its upper end against the lower end of the valve stem guide 45 while its lower end bears against a screw nut 56 on the threaded lower end of this valve stem. By turning this adjusting screw nut so that it moves either up or down on its valve stem the tension of the spring 55 which resists the opening movement of this check valve maybe regulated so as to admit a greater or a lesser quantity of gaseous mixture through this particular conduit into the engine by the suction of the pump plunger. By this means the amount of the mixture may be varied manually to suit the altitude at which the aeroplane is traveling, the tension on the spring 55 being made lighter so that a larger volume of mixture is admitted when the aeroplane is traveling at a high altitude and the atmosphere is less dense, while. the tension of this spring is increased so that the check valve 41 opens less freely and therefore permits a smaller volume of mixture to enter the engine when the aeroplane is traveling at a lower altitude where the atmosphere is more dense.

This same effect may be produced automatically by mechanisms which are responsive to variations in the density of the atmosphere. Such a mechanism is shown in connection with the check valve 42, in Figs. 1, 2 and 4, and comprises a shell or casing 57 mounted on the base or other stationary part of the engine and divided by a movable diaphragm or partition 58 into a lower closed air chamber 59 and an upper vented air chamber 60 which communicates with the outer atmosphere by means of openings .61 in the top of this chamber. I From the central part of this diaphragm a shifting rod 62 extends upwardly through a guide 63 in the top of the upper air chamber, and a spring 64 is employed for connecting the upper end of the shifting rod 62 with the lower end of the stem 44 of the check valve 42. In low altitudes the greater pressure of the air entering the upper chamber 60 through the openings 61 causes the diaphragm to be depressed and the spring 64 to be strained to a greater extent so as to increase the resistance of the check valve 42 against opening under the suction action of ,the pump plunger, thereby reducing the amount of gaseous mixture which is drawn into the engine. When however, the engine is traveling in high altitudes where the air is less dense the reduced pressure of the air against the upper sides of the diaphragm causes the tension of the spring 64 to become relaxed accordingly and thereby permit the check valve 42 to open easier and 'allow a proportionately increased volume of gaseous mixture to be drawn by the pump plunger into the engine. The barometric regulator therefore automatically adapts the I supply of fuel to the engine in accordance with the requirement under different atmospheric conditions.

In order to steady the movement of the diaphragm a spring 65 is preferably mounted on the rod 62 between the top of the casing 57 and the diaphragm so that it operates to assist in depressing the diaphragm.

In the modified construction of the engine containing my improvements shown in Fig. 8, the head 66 forming the upper end of the firing cylinder 67 and also part of the pump plunger 68 is provided on its upper side with heat radiating ribs or fins 69 which carry away some of the heat developed in the firing cylinder and warm the incoming gas in the upper part of the pump cylinder 70 so as to thoroughly vaporize the fuel and promote rapid ignition of the same.

The central terminal 71 of the spark plug in the construction in Fig. 8 is provided with upwardly extending brush rod 72 which slides in contact with a stationary metal disk or plate 7 3 connected with a binding post 74. This plate and binding post are mounted on a tubular insulating cap secured to the upper end of the pump cylinder. One side of the electric source is grounded on the metal parts of the engine so as to connect with the other terminals 75 of the spark plug and the other side of the sour-re connects with the binding post 74, and during theoperation of the engine the brush rod 72 by sliding on the plate 73 keeps the

terminals

71, 75 in the electric cirruit for producing the spark for igniting the charge.

The means for controlling the operation "of the=main intake valve 76 in the construction shown in Fig. 8 comprises a controlling cylinder 77 arranged on top of the pump cylinder '70 and opening at its lower end into the latter while its upper end is provided "with a check'valve 78 which permits air to escapefr'om this end of the cylinder but prevents entrance of the same, a controlling piston 79, arranged in the controlling cylinder, an'upright connecting rod 80 connected at lts lower end with "the main intake valve 7 6 and "at its upper end with the controlling piston 7 9 and a spring 81'surrounding this connectin'g rod and engaging its upper end with a bridge 82 mounted on the pump plunger "68 and its lower end against a shoulder 84cm the connecting rod 80 so as to yieldingly hold the intake valve in its *open osition. During the downward stroke or the firing cylinder the intake'valve 76 is "hlds'hut "by "the gaseous mixture therein which" is being compressed and also by the upward pulling'efie'ct of thecontrolling pis- "ton =79 as the latter in its descent in the controlling cylinder produces a partial vacuum in the upper end of this cylinder, these combined forces being reater than the tension of the spring 81. he ascent'of the controlling piston is comparatively free inasmuch as the check valve *7 6 at this time opens and permits the escape of the air from theup'per endof the controlling cylinder, Whichenable's the expanding burning gases in the firingcylinder to hold'the main ini take valve 7 6- shut during the upward stroke of the firing cylinder. When however the exhaust ports of the firing cylinder are opened by'the 'firing piston during the last part of the firingor expansion strokes of these members and the pressure within the fii-ing 'cylinderdrops, due to the escape of thespent gases, then the pressure of the spring '81 together with the'pressure ofthe compressed charge of gasin the upper end of the pump cylinder opens the main'valve 76 T and i this gas 1 rushes into the firing oylinderand fills-the same asthe 'burnt gas esca "es therefrom. v

p n Fig. 8 are also shown means for regulating the-explosive mixture supply to the engine'whih-are responsiveto variations in *the thermal conditions in the engine as Well 'as 'fluetuiations in'the density of the atmosphere. As is well known a hot mixture cannot be-compre'ssed to the samedegree as a cold-one: of the same volume. To thoroughly vaporize the fuel, especially the lower grades, requires considerable-heat. In order to obtain the highest'-efiiciency,- anengine s'hould becapable o'f using' 'a hot mixture in Which the fuel has been thoroughly vapori ed and at the same time maintain its degree of compression constant. The example of means'in Fig. 8 showingsu'ch a thermostatic control combined with a bitIOIIlQtIlG control is constructed as follows 85 represents a barometric shell or casing mounted on a stationary part of the engine and divided by a flexible diaphragm or partition 86 into a lower sealed air chamber 87 and an upper vented air chamber 88 which is open to the atmosphere. 89 represents a shifting rod guided in the upper part of the shell and'90 a spring surrounding this rod and interposed between the top of the shell and" the diaphragm'so as toyieldingly hold the latter in a depressed position. 91 represents a regulating lever pivoted at one end to the upper endof the-diaphragm rod. To the central part of this leveris connected a spring 92 which is in turn connected with thelower end of the valve rod 93 of the check valve 94 arranged inthe "fuel supply conduit 95 of the engine.

96 represents a pipe orconduitforming part of the system whereby water is circulated around various part's ofthe engine which are'heated 'for the purpose of'cooling the same. In this water conduit is arranged a thermostatic -rod=or ele'ment97 which is adapted to-expand and contract in response to a rise and {fall in the temperature of the water passing through the circulating conduit. 'One end of this thermostatic rod is xed on thefpipe, as shown at 9'8, and=the other is connected with a rock arm99 arranged withinthe pipe 96 and mounte'd'on a rock shaft 100 journaled in suitable bearings on this pipe. "Outsideo'f the latterthe rock shaft l00is provided with a rock arm 101 WhlCh'lS connected by a rod 102 with the other end of the lever'9l.

As "the temperature of the engine increases, the temperature of the explosive mixture is-also raised. s a result the thermostatio element 97 in t 1e Water conduit exp ands and shifts the "regulating lever 91 so as to reduce the tension on the spring" 92 and permit the check valve 94 to'open easier. A greater volume of mixture is thereby allowed to enterthe' engine and be compressed, whereby the com ression-is maintained constant. Any changes in the density of the air will cause thediaph'ragm 86to rise or fall and thereby' also-lessen o1"inc're'ase the tension-of the spring'92 and "either increase or decrease the volume of mixture which is permitted" to enter the engine.

I claim as-my invention 1. An internal combustion engine comprising a reciprocating firing cylinder, a'recipro'cating firing piston arranged in said cylinder and moving oppositely thereto, and means for I supplying --said "cylinder with an explosive medium comprising a pump lunger connected with said 1 firing cylinder and a ump c linder in Whichsaid' phlhger-Teciprocates and is adapted to receive an explosive medium on opposite sides of said plunger.

2. An internal combustion engine comprising a reciprocating firing cylinder, a reciprocating firing piston arranged in said cylinder and moving oppositely thereto, and means for supplying said cylinder with an explosive medium comprising a pump plunger connected with said firing cylinder, and a pump cylinder in which said plunger reciprocates and is adapted to receive an explosive medium on opposite sides of said plunger, the diameter of said plunger and the bore of said pump cylinder being greater than the diameter of the periphery of said firing cylinder.

3. An internal combustion engine comprising a reciprocating firing cylinder, a re ciprocating firing piston arranged in said cylinder and moving oppositely thereto. and means for supplying said cylinder with an explosive medium comprising a pump plunger connected with said firing cylinder and a pump cylinder in which said plunger reciprocates and is adapted to receive an explosive medium on opposite sides of said plunger, said pump cylinder being provided with a supply passage which communicates with said cylinder at its lower end and at a place between its upper and lower ends.

4:. An internal combustion engine com prising a reciprocating firing cylinder, a reciprocating firing piston arranged in said cylinder and moving oppositely thereto. and means for supplying said cylinder with an explosive medium comprising a pump plunger connected with said firing cylinder, a pump cylinder in which said plunger reciprocates and is adapted to receive an explosive medium on opposite sides of said plunger, said pump cylinder being provided with a supply conduit having an outer section, an inner section which communicates with said pump cylinder at its lower end and at a place between its upper and lower ends, and a valve seat between said inner and outer sections and an inwardly opening check valve engaging said seat.

5. An internal combustion engine comprising a reciprocating firing cylinder, a reciprocating firing piston arranged in said cylinder and moving oppositely thereto. and means for supplying said cylinder with an explosive medium comprising a pump plunger connected with said firing cylinder, a pump cylinder in which said plunger reciprocates and is adapted to receive an explosive medium on opposite sides of said plunger. said pump cylinder being provided with a supply conduit having a section which opens into the lower end of said pump cylinder' and at a place between its upper and 6. An internal combustion engine comprising a reciprocating firing cylinder, a reciprocating firing piston arranged in said cylinder, a pump plunger connected with said cylinder, a pump cylinder which receives said plunger, an intake valve arranged in said plunger, and means for controlling the opening and closing of said intake valve comprising a controlling cylinder opening at its inner end into said pump cylinder and a piston arranged in said controlling cylinder and operatively related to said intake valve.

7. An internal combustion engine comprising a reciprocating firing cylinder, a reciprocating firing piston arranged in said cylinder. a pump plunger connected with said cylinder, a pump cylinder which receives said plunger, an intake valve arranged in said plunger, and means for controlling the opening and clos ng of said intake valve comprising controlling cylinder opening at its inner end into said pump cylinder. a controlling piston arranged in said controlling cylinder, a rod connecting said intake valve and controlling p ston. and a spring operating normally to hold said intake valve open.

8. An internal combustion engine comprising a reciprocating firing cylinder, a reciprocating firing piston arranged in said cylinder. a pump plunger connected with said cylinder. a pump cylinder which receives said plunger, an intake valve arranged in said plunger, means for controlling the open ng and clos ng of s d intake valve compr sing controlling cylinder opening at its inn r end into said pum cylin der. a controlling piston arranged in said controlling cylinder. a rod connect ng said intake valve and controll ng p ston. a spr ng operatin normally to hold s d intake valve open. and an outwardly opening check valve arranged on the outer end of said controlling cylinder.

9. An internal combustion engine compris ng a pump cylinder. a pump plunger arranged in said pump cylinder. a reciprocating firing cylin er connec ed with said pump plunger and having a head one side of which is exposed to the interior of said pump c linder and provided with heat rad a ing fins which operate to ra se the temperature of the fuel in said pump cylinder, and a working piston arranged in said firing cylinder.

FRANK S. WAHL.