Lever-type Two-cycle Internal Combustion Engine

Abstract

An internal combustion engine having opposed power cylinders and separate air or air-fuel charging cylinders, and a lever system interconnecting the power and air or air-fuel charging cylinder pistons with each other and with a crankshaft. The lever system comprises the piston rods of the power and air or air-fuel pistons, each piston rod being pivotally connected at one end to its respective piston and being pivotally connected at its opposite end to the corresponding opposite ends of the other two piston rods. One of said piston rods--namely, the piston rod of the air or air-fuel charging cylinder--is connected intermediate its ends to a crankshaft and said piston rod accordingly functions as the lever which drives the crank arm of the engine.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

Lever-type internal combustion engines, whether based on gasoline or diesel engine principles.

2. Description of the Prior Art

The use of lever-type engines dates back to the early days of automotive and internal combustion engine development. Historic advances in engine design necessarily include the brainchild of Alvah A. Powell, who saw advantages in changing long stroke piston travel to shorter crank throw through leverage. More recent improvements include opposed cylinder two-cycle engines such as the type disclosed in U.S. Pat. No. 2,445,720 to Wenzel.

Known engines, however, include many undesirable features which designers in the art have unsuccessfully sought to overcome. Relatively complicated linkages with long connecting rods are characteristic of engines known to the art. In addition, vibration problems created by imbalance of moving parts result in a loss of engine efficiency as well as ever increasing engine wear. The use of flywheels mounted on the ends of crankshafts and equipped with counterbalance weights have only added to already complicated engine structures.

SUMMARY OF THE INVENTION

This invention relates to two-cycle internal combustion engines. The same principle, although not here specified, may be used in external combustion engines such as steam engines, in which a relatively large stroke-to-bore ratio is desirable for increasing crankshaft torque. The invention will, however, be described herein in relation to a two-cycle internal combustion engine, but this description is not intended to limit the application of the invention except to the extent and scope of the appended claims.

Specifically, in the present invention the power cylinders are axially aligned in opposed positions, the piston rod of each said power (work) cylinder being pivotally connected at its outer end to the corresponding end of the piston rod of the opposed power cylinder. An air or air-fuel charging cylinder is provided for each pair of opposed power cylinders. Its longitudinal axis intercepts the common longitudinal axis of the two power cylinders at right angles thereto. In the preferred form of this invention the opposed power cylinders occupy a common horizontal plane. The air or air-fuel charging cylinder extends vertically, its longitudinal axis being normal to said horizontal plane.

The piston rod of the air or air-fuel charging cylinder is connected at its outer (lower) end to the connected outer ends of the piston rods of the horizontally opposed power cylinders. The relationship of all three piston rods to their respective pistons and to each other is the same in all three cases--that is, the inner end of each piston rod is pivotally connected to its respective piston, and the outer end of each piston rod is pivotally connected to the corresponding outer ends of the other two piston rods.

The crankshaft is located above the horizontally opposed power cylinders and below the vertically extending air or air-fuel charging cylinder. The piston rod of the air or air-fuel charging cylinder is connected, intermediate its ends, to the offset crank pin of the crankshaft. Accordingly, for the purposes of this description, the piston rod of the air or air-fuel charging cylinder may be considered to be the operative lever of the lever system of the present invention. In this arrangement, the inner end of the lever (connected to the piston rod of the air or air-fuel charging cylinder) is its fulcrum end; the outer end of said lever (which is connected to the outer ends of the piston rods of the power cylinders) may be considered to be its effort end; and the intermediate connection between the lever and the crankshaft may be considered to be the load or work-applying portion of the lever.

It will be understood from this description and from the appended drawing that there is no fixed axis for any part of the lever. The fulcrum moves linearly in a vertical line, reciprocating between upper and lower positions. The load- or work-applying portion of the lever rotates in a circular path about the crankshaft axis. The effort end of the lever describes an orbital path.

The principal object of this invention is the provision of a lever-type engine of the character described, wherein the power or work cylinders are axially aligned and opposed to provide a direct thrust, inertia absorbing cushion in each cylinder of each pair of opposed cylinders, thereby freeing the crankshaft from excessive inertial loading, and rendering it feasible to provide a relatively large stroke-to-bore ratio in the power cylinders.

It is an object of this invention to provide a lever-type engine of the character described which employs the slidable fulcrum principle in order to produce a relatively large stroke-to-bore ratio in the power cylinders, while employing a small crank arm radius and relatively short connecting linkages between the pistons and the crankshaft.

Another object of the invention is to increase piston dwell time at each end of the power piston stroke, thereby increasing the time for homogenization of the air-fuel mixture to promote more complete combustion within the power cylinder at the end of the compression stroke and beginning of the power stroke, and more complete scavenging and recharging at the end of the power stroke and beginning of the compression stroke.

A further object of this invention is to provide, within feasible total volume, an engine having a long piston stroke relative to the cylinder diameter to promote more complete combustion of the air-fuel mixture taken into the cylinder such that pressure and combustion levels approach zero value before the exhaust port is opened at the end of the power stroke.

A still further object of the invention is to provide an internal combustion engine which will produce minimum exhaust pressure and particle emission to minimize air pollution.

The present invention provides a lever engine comprising a plurality of power cylinders (preferably in multiples of four or eight) arranged in pairs in such manner that the cylinders of each pair are directly opposed in coaxial relationship in a horizontal plane. In an eight-cylinder engine as herein shown and described, there are four pairs of opposed cylinders arranged side by side in parallel relationship in a common horizontal plane. There is a single air or air-fuel charging cylinder for each pair of opposed power cylinders, and in an engine having four pairs of opposed power cylinders (eight cylinders in all) there are four charging cylinders. These charging cylinders are arranged side by side in parallel relationship, in a common vertical plane, the axes of said charging cylinders extending vertically and intercepting the power cylinder axes at right angles. The crankshaft extends horizontally in the vertical plane which the charging cylinders occupy, and in a horizontal plane above the horizontal plane which the opposed power cylinders occupy. The crankshaft has four crank arms which are equally spaced from each other at 90.degree. intervals, there being one crank arm for each pair of opposed cylinders. Power is delivered to the crankshaft by at least two power cylinders at all times. Each air or air-fuel charging cylinder supplies two power cylinders with air or an air-fuel mixture, there being four charging cylinders and eight power cylinders. Each charging cylinder will communicate with two power cylinders when their respective inlet ports are opened at the end of a power or work stroke. At such time the piston of the charging cylinder will reach its extreme upper position in its upwardly moving compression stroke, so as to deliver the required charge of air or air-fuel mixture to the two power cylinders with open inlet ports.

As has above been stated, the lever system of each pair of opposed power cylinders and their adjacent charging cylinder comprises the piston rods of the three cylinders pivotally connected to each other at their respective outer ends. The piston rod of the charging cylinder is connected intermediate its ends to the crankshaft, and accordingly may be deemed and designated the lever of the lever-type engine herein described and claimed. The charging cylinder (piston) performs two functions:

1. It provides compressing means for compressing air or an air-fuel mixture and delivering same to the power cylinders.

2. It provides a vertically reciprocating fulcrum for the lever which drives the crankshaft.

It is this arrangement, wherein the three piston rods (of each pair of work cylinders and one air-charging cylinder) comprise the entire lever system of the engine, that renders it possible to dispense with the complicated lever systems and linkages of the lever engines of the prior art. It is the use of the pivotal connection between the piston of the air-charging cylinder and its piston rod as the fulcrum of the lever system that makes it possible to dispense with the supplemental fulcrum systems of prior engines.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a plan view of an eight-cylinder, two-cycle engine made in accordance with the principles of this invention.

FIG. 2 is a section through a vertical plane which is parallel to the axis of the crankshaft and taken on the line 2--2 of FIG. 12.

FIG. 3 is a second vertical section corresponding to FIG. 2 but taken on the line 3--3 of FIG. 13.

FIG. 4 is a third vertical section corresponding to FIG. 2 but taken on the line 4--4 of FIG. 14.

FIG. 5 is a fourth vertical section corresponding to FIG. 2 but taken on the line 5--5 of FIG. 15.

FIG. 6 is a fifth vertical section corresponding to FIG. 2 but taken on the line 6--6 of FIG. 16.

FIG. 7 is a section through a vertical plane which is at right angles to the axis of the crankshaft and is taken on the line 7--7 of FIG. 2.

FIG. 8 is a second vertical section corresponding to FIG. 7 but taken on the line 8--8 of FIG. 3.

FIG. 9 is a third vertical section corresponding to FIG. 7 but taken on the line 9--9 of FIG. 4.

FIG. 10 is a fourth vertical section corresponding to FIG. 7 but taken on the line 10--10 of FIG. 5.

FIG. 11 is a fifth vertical section corresponding to FIG. 7 but taken on the line 11--11 of FIG. 6.

FIG. 12 is a section through a horizontal plane and taken on the line 12--12 of FIG. 2.

FIG. 13 is a second horizontal section corresponding to FIG. 12 but taken on the line 13--13 of FIG. 3.

FIG. 14 is a third horizontal section corresponding to FIG. 12 but taken on the line 14-14 of FIG. 4.

FIG. 15 is a fourth horizontal section corresponding to FIG. 12 but taken on the line 15--15 of FIG. 5.

FIG. 16 is a fifth horizontal section corresponding to FIG. 12 but taken on the line 16--16 of FIG. 6.

DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION

Referring now to the details of the invention as illustrated in the drawing, it will be observed that there are four pairs of power cylinders, eight power cylinders in all, designated respectively as follows: 10a and 10b, 12a and 12b, 14a and 14b, and 16a and 16b. Associated with these four pairs of power cylinders are four air or air-fuel charging cylinders, designated respectively 10c, 12c, 14c and 16c. A housing 20 supports the power and charging cylinders in the arrangement shown in the drawing, and it will shortly be described. Also supported by and within the housing is a crankshaft 22, there being only one crankshaft for the eight power cylinders and the four charging cylinders.

It will now be observed that the eight power cylinders are disposed in a common horizontal plane, each pair of said cylinders being coaxially aligned and opposed, the four pairs of opposed cylinders being arranged in side-by-side relationship so that the longitudinal axis of each pair is parallel to the longitudinal axes of the other three pairs. The charging cylinders are also arranged in side-by-side relationship, their respective longitudinal axes being disposed in parallel relationship to each other in a common vertical plane centered between power cylinders 10a, 12a, 14a and 16a, on the one hand, and power cylinders 10b, 12b, 14b and 16b, on the other hand. The longitudinal axis of crankshaft 20 also lies in the vertical plane of the charging cylinders, and it is also disposed in a horizontal plane located between the power cylinders on the one hand and the charging cylinders on the other.

It will be understood that the power cylinders are respectively provided with pistons and piston rods designated as follows:

power cylinder 10a--piston 10d, piston rod 10e

power cylinder 10b--piston 10f, piston rod 10g

power cylinder 12a--piston 12d, piston rod 12e

power cylinder 12b--piston 12f, piston rod 12g

power cylinder 14a--piston 14d, piston rod 14e

power cylinder 14b--piston 14f, piston rod 14g

power cylinder 16a--piston 16d, piston rod 16e

power cylinder 16b--piston 16f, piston rod 16g

By the same token, the air or air-fuel charging cylinders are also provided with pistons and piston rods designated as follows:

charging cylinder 10c--piston 10h, piston rod 10i

charging cylinder 12c --piston 12h, piston rod 12i

charging cylinder 14c--piston 14h, piston rod 14i

charging cylinder 16c--piston 16h, piston rod 16i

The crankshaft 22 has four crank pins spaced at 90.degree. intervals and designated as follows:

for piston rod 10i--crankpin 22a

for piston rod 12i--crankpin 22b

for piston rod 14i--crankpin 22c

for piston rod 16i--crankpin 22d

With further reference to the details of the invention as illustrated in the drawing, it will be noted that the power cylinders are provided with heat exchange fins 24. It will thereby be understood that the preferred embodiment of the invention is an air-cooled engine. However, it should also be understood that the invention is not intended to be limited to air-cooled engines, and the principles of the invention may equally be applied to engines which are water-cooled.

It will further be noted that the power cylinders are long in relation to the diameter of their respective pistons, that is, the length of the stroke of the power pistons exceeds their diameter. This is known as an undersquare design, and the ratio of stroke-to-bore may exceed 1:1 to any desired extent, even as high as approximately 2:1, as schematically shown in the drawing. The invention is not limited to any specific stroke-to-bore ratio.

The mechanical linkages which are significant in the execution of this invention are the following: The pistons rods of the several power cylinders are pivotally connected at their inner ends to their respective pistons by means of cross pins 26. The piston rods of each pair of power cylinders are pivotally connected to each other by means of cross pins 28. Similarly, the piston rods of the several air charging cylinders are pivotally connected at their inner ends to their respective pistons by means of cross pins 30. At their outer ends the piston rods of the air charging cylinders are pivotally connected to the outer ends of the piston rods of the power cylinders by means of above mentioned pin 28. It will accordingly be understood that the several piston rods of the power and air charging cylinders are pivotally connected at their inner ends to their respective pistons and pivotally connected at their outer ends to each other.

The piston rods of the air charging cylinders are also connected to the crankshaft. More particularly, piston rod 10i is rotatably connected to crank pin 22a, piston rod 12i is rotatably connected to crank pin 22b, piston rod 14i is rotatably connected to crank pin 22c, and piston rod 16i is rotatably connected to crank pin 22d. The crankshaft is, of course, adequately supported by bearings in any conventional manner. Schematically it is indicated in the drawing that the housing is provided with five bearing blocks, 32, 32a, 32b, 32c and 32d, respectively; suitable split bearing sleeves 34, 34a, 34b, 34c and 34d are provided to support the crankshaft on said bearing blocks. Spacer sleeves 36 are provided where necessary. However, it will be understood that the drawing is primarily schematic and the showing of the several working parts is exaggerated for purposes of clarity, and relative proportions of the parts as shown in the drawing should not be taken literally. This is particularly true of the crankshaft, including the spacing between the bearing supports and the crank pins.

As has above been indicated, this invention is primarily applicable to two-cycle internal combustion engines, and the engine which is shown in the drawing illustrates this application of the invention. There is no valve system connected with the power cylinders other than open ports formed in those cylinders and the pistons themselves, which open and close the ports. Specifically, each power cylinder is provided with an inlet port 40 and an outlet or exhaust port 42. The inlet ports of the several power cylinders are connected to the air charging cylinders by means of suitable tubes, as will shortly be described. The outlet or exhaust ports are connected to an exhaust manifold and exhaust pipe, neither of which is shown in the drawing because it is entirely conventional.

It will be noted that the inlet ports 40 are of smaller diameter than the outlet or exhaust ports 42. In the preferred form of this invention, the inlet and outlet ports are not coaxial, but they do register with each other to the extent of the diameter of the inlet ports. When a power piston reaches its extreme outermost position relative to the cylinder in which it is housed, as for example piston 10d in cylinder 10a, as shown in FIG. 7, both ports 40 and 42 are fully open. When the piston occupies a less extreme outer position, as does piston 10d in cylinder 10a in FIG. 11, inlet port 40 is closed while outlet port 42 is partly open and partly closed. Depending upon the direction of movement of the piston relative to these two ports, outlet port 42 may first open and then inlet port 40, or inlet port 40 may first close and then outlet port 42.

The significance of this opening and closing sequence is the following: When a power piston, e.g., power piston 10d, moves outwardly in its power stroke, outlet port 42 first opens to allow the combustion gases to escape. This occurs immediately before the piston reaches its outermost position relative to the cylinder in which it is disposed. By the time the outermost position is reached, inlet port also opens, and this enables an inward rush of air to scavenge the cylinder and thereby drive the remaining combustion gases out of the cylinder through outlet port 42. The combustion gases are thereby replaced by a fresh charge of air or air-fuel mixture, as the case may be. When the piston now reverses its stroke and moves inwardly relative to the cylinder in which it is mounted, inlet port 40 closes, thereby shutting off the supply of air or air-fuel mixture. Further inward movement of the piston closes the outlet port, and the fresh charge of air or air-fuel mixture may now be compressed. This sequence and the functional relationship between the power and air charging cylinders will shortly be discussed in greater detail to describe the functioning of the entire engine.

In the two-cycle engine which is illustrated in the drawing, the function of the air charging cylinders is to scavenge and recharge the power cylinders. It will be observed that each air charging cylinder has an inlet port 44 and an outlet port 46. The inlet port communicates with the atmosphere to receive air, or with a carburetor to receive an air-fuel mixture. A check valve 48 is provided at inlet port 44 in order to allow air or an air-fuel mixture to enter the air charging cylinder and said check valve automatically closes to prevent discharge of the air or air-fuel mixture from said cylinder. A second check valve 50 is provided at outlet port 46, and its function is to allow the air or air-fuel mixture to leave the cylinder, and it automatically closes to prevent a reverse flow through outlet port 46 when the air charging cylinder is in process of receiving a fresh charge of air or air-fuel mixture. It will be understood (and it will be seen in the drawing, e.g., in FIG. 1) that each air charging cylinder is connected to two power cylinders. Accordingly, it is desirable to provide a Y-type fitting at the outlet port 46 of each air charging cylinder, the two branches of the Y-fitting being connected by suitable tubing to the two power cylinders with which each air charging cylinder is associated. The relationship between the several air charging cylinders on the one hand and power cylinders on the other, and the air lines between the two groups of cylinders, are shown pictorially in FIG. 1 of the drawing and schematically in FIGS. 12, 13, 14, 15 and 16. In FIG. 1, as well as in FIGS. 12 through 16, it is shown that air charging cylinder 10c is connected by means of air lines 60a and 60b to power cylinders 14a and 16b , respectively. It is similarly shown that air charging cylinder 12c is connected by means of air lines 62a and 62b to power cylinders 16a and 14b, respectively. Air charging cylinder 14c is connected by means of air lines 64a and 64b to power cylinders 12a and 10b, respectively. And finally, air charging cylinder 16c is connected by means of air lines 66a and 66b to power cylinders 10a and 12b, respectively. It is of course understood that these several air lines are connected between the outlet ports 46 of the air charging cylinders and the inlet ports 40 of the power cylinders. Accordingly, each air charging cylinder is connected to and is responsible for the scavenging and recharging of two power cylinders.

It will also be understood that the power cylinders require not only air but also fuel and means for igniting the air-fuel mixture. If the engine which embodies the present invention is a gasoline fuel internal combustion engine, it has one or more carburetors or other air-fuel mixing and feeding devices. Assuming the existence and use of a carburetor, it will be understood that it is connected to the several air charging cylinders and that they supply the power cylinders with an air-fuel mixture. Ignition would require the use of spark plugs 66. On the other hand, if the invention is embodied in a diesel engine, the air charging cylinders would supply only air to the power cylinders, and fuel would be injected into said power cylinders by means of fuel injectors 68.

It will also be understood, and it is clearly shown in the drawing, that the air charging cylinder which is mechanically connected to a given pair of power cylinders is not connected to those particular power cylinders for air supply. As an illustration, FIG. 7 shows a pair of power cylinders 10a and 10b and an air charging cylinder 10c mechanically connected to said power cylinders through their respective pistons and piston rods. However, air charging cylinder 10c does not supply air to power cylinders 10a and 10b. Instead, as has above been indicated and as is shown in FIG. 1 and FIGS. 12 to 16, inclusive, air charging cylinder 10c is connected by air lines 60a and 60b to power cylinders 16a and 14b.

The mechanical operations of a representative pair of power cylinders and the air charging cylinder which is mechanically associated therewith will now be described. FIGS. 7, 8, 9, 10 and 11 depict the various stages in a cycle involving the pistons and piston rods of power cylinders 10a and 10b and air charging cylinder 10c. In all of these figures the crankshaft rotates in counterclockwise direction, as indicated by curved arrows 70.

Starting with FIG. 7, it will be noted that power piston 10d is at its extreme outer position following a power stroke and power piston 10f is at its innermost position following a compression stroke. Ports 40 and 42 in cylinder 10a are now open, so that the combustion gases may escape through the outlet port 42 and the fresh charge of air may enter through inlet port 40. The inrush of fresh air completes the evacuation of combustion gases and fills the cylinder. At the same time, the air or air-fuel mixture within power cylinder 10b is compressed preparatory to a power stroke of piston 10f. Ignition occurs, e.g., by the use of spark plug 66, and an explosion takes place within power cylinder 10b.

In the meantime, piston 10h in air charging cylinder 10c is moving upwardly, and is thereby expelling air from said air charging cylinder through open valve 50 and driving it into power cylinders 16a and 14b.

The next stage in the operation is shown in FIG. 8. Pistons 10d and 10f now move leftwardly, an explosion having taken place in cylinder 10b driving piston 10f outwardly therefrom and compression taking place concurrently therewith in cylinder 10a. Air charging piston 10h has now moved to its extreme uppermost position in cylinder 10c, and this marks the end of its air charging operation with respect to power cylinders 16a and 14b.

The next stage in the operation is shown in FIG. 9, wherein power piston 10d has reached its extreme inward position in cylinder 10a and power piston 10f has reached its outermost position in cylinder 10b. This is the reverse of their respective positions as shown in FIG. 7. The outlet port 42 of cylinder 10b is opened first to start the exhaust of the combustion gases from said cylinder, and inlet port 40 then opens to receive a fresh charge of air from air charging cylinder 14c. As has above been indicated, the inrush of fresh air completes the process of exhausting the combustion gases and the fresh air accordingly takes the place of the combustion gases in power cylinder 10b. On the opposed side power piston 10d has reached its innermost position wherein it compresses the air in cylinder 10a. Since it is assumed that a carburetor is being used, a suitable charge of fuel is entrained with the air, and what is compressed in cylinder 10a is a combustible air-fuel mixture.

At the same time piston 10h moves downwardly in air charging cylinder 10c, and it is thereby drawing a fresh charge of air into said cylinder through open valve 48.

The next stage in the operation is shown in FIG. 10, wherein the power pistons are depicted moving rightwardly. Specifically, combustion has started in power cylinder 10a, driving piston 10d outwardly therefrom and forcing piston 10f inwardly relative to cylinder 10b. Since cylinder 10b has received a charge of fresh air entrained with fuel, piston 10f is now in the process of compressing same into an explosive mixture. Piston 10h has now reached its outermost position in cylinder 10c, and it has drawn a full charge of air, entrained with fuel, into said cylinder. Cylinder 10c is now ready to deliver a fresh charge of air and fuel to the power cylinders 16a and 14b with which it is connected.

FIG. 11 depicts the next stage in the operation, just short of the starting stage shown in FIG. 7. The expansion of the combustion gases in cylinder 10a continues to drive power cylinder 10d outwardly, but it has not yet reached its outermost position shown in FIG. 7. By the same token, piston 10 f is moving toward its extreme innermost position in cylinder 10b, but it is still short of the starting position which is shown in FIG. 7. More particularly, piston 10d has moved outwardly a sufficient distance to partially open the outlet port 42 in cylinder 10a, but inlet port 40 in said cylinder remains closed. Accordingly, the combustion gases in cylinder 10a begin to exhaust out of said cylinder, but they are not yet being forced out of the cylinder by the inrush of a new charge of air. On the opposite side piston 10f is compressing the air-fuel mixture in cylinder 10b, but compression has not yet been completed.

Piston 10h is again moving upwardly in air charging cylinder 10c, and it is driving air entrained with fuel out of said cylinder through open valve 50 and into cylinders 16a and 14b. The final stage in the operation is the same as the initial stage depicted in FIG. 7. One complete cycle has now been concluded, and the next cycle is about to begin.

The relationship among the several air charging cylinders and the manner in which their respective piston rods operate upon the crankshaft may be seen in FIGS. 2, 3, 4, 5 and 6. These figures coincide with FIGS. 7, 8, 9, 10 and 11 in the sense that the several stages of the pistons shown in FIGS. 7, 8, 9, 10 and 11 correspond identically to their stages in FIGS. 2, 3, 4, 5 and 6.

Turning now to FIG. 2, it will be seen that piston 10h occupies the same position in air charging cylinder 10c in that figure which it does in FIG. 7. Similarly, piston 10h occupies the same position in FIG. 3 which it does in FIG. 8, the same position in FIG. 4 which it occupies in FIG. 9, the same position in FIG. 5 which it occupies in FIG. 10, and the same position in FIG. 6 which it occupies in FIG. 11. By the same token, power pistons 10d and 10f occupy the same positions in their respective cylinders 10a and 10b in FIG. 7 which they occupy in FIG. 12, the same positions in FIG. 8 which they occupy in FIG. 13, the same positions in FIG. 9 which they occupy in FIG. 14, the same positions in FIG. 10 which they occupy in FIG. 15, and the same positions in FIG. 11 which they occupy in FIG. 16. It will similarly be understood that FIGS. 2 through 6 are vertical sections (at least in part) of FIGS. 12 through 16. Consequently, the relative positions of all of the pistons shown or indicated in FIGS. 2 through 6 correspond to the relative positions of the same pistons in FIGS. 12 through 16.

Selecting FIG. 2 for illustrative purposes, it will be seen that piston 10h occupies the same position in cylinder 10c of FIG. 2 which it occupies in FIG. 7, piston 12h occupies the same position in cylinder 12c of FIG. 2 which it occupies in FIG. 9, piston 14h occupies the same position in cylinder 14c of FIG. 2 which it occupies in FIG. 10, and piston 16h occupies the same position in cylinder 16c of FIG. 2 which it occupies in FIG. 8. The same may be said of FIGS. 3 through 6. Each of the pistons of each of the air charging cylinders shown in FIGS. 3 through 6 is shown in a position which corresponds to one of the positions shown in FIGS. 7 through 11.

The operation of the engine may best be understood from FIGS. 12 through 16 and their corresponding vertical sections shown in FIGS. 2 through 6.

Turning now to FIG. 12, it will be understood that power cylinders 10a and 12b are shown receiving a charge of air entrained with fuel, from air charging cylinder 16c. This is evidenced by heavy lines 66a and 66b and the arrowheads which are superimposed upon them. This process completes the exhaustion of the combustion gases from said cylinders and recharges them with an air-fuel mixture preparatory to the combustion stroke.

Concurrently with the air charging operation last described, the compressed air-fuel mixture in cylinder 12a ignites and commences to burn to begin the power stroke of the piston in that cylinder. This is equally true of the compressed air-fuel mixture in cylinder 10b, and the ignition of this mixture commences the power stroke of the piston in that cylinder. It will therefore be observed that since the pistons in cylinders 10a and 10b are opposed and connected through their respective piston rods, and since the pistons in cylinders 12a and 12b are also opposed, the last described power strokes commencing in cylinders 12a and 10b will produce compression strokes in cylinders 12b and 10a.

Also concurrently with the foregoing expansion of the combustion gases in cylinders 14a and 16b causes compression of the air-fuel mixtures in cylinders 14b and 16a. The direction of movement of the several pistons in FIG. 12 is shown by the arrows which relate to them.

FIG. 13 represents the next phase in the operation of the engine. In this figure cylinders 14a and 16b are shown receiving a charge of air entrained with fuel, and once again the inrush of this flow completes exhaustion of the combustion gases of the prior power stroke and introduces into the cylinders a fresh charge of such air-fuel mixture. At the same time, the compressed air-fuel mixture in cylinders 14b and 16a ignites, and the expanding combustion gases begin the power strokes of the pistons in those cylinders. Also concurrently therewith, the expanding combustion gases in cylinders 10a and 12b continue the power strokes of the pistons in those cylinders and produce compression strokes of the pistons in cylinders 10b and 12a.

FIG. 14 shows the next stage in the operation of the engine. Cylinders 10b and 12a are shown receiving a fresh charge of an air-fuel mixture and the compressed air-fuel charges in cylinders 10a and 12b are now ignited in said cylinders to begin the power stroke of the pistons therein. Such power stroke will of course result in compression of the fresh charges in cylinders 10b and 12a. Concurrently with the foregoing, the expanding combustion gases in cylinders 14b and 16a are producing a power stroke of the pistons in those cylinders, resulting in compression strokes of the pistons in cylinders 14a and 16b.

The next stage in the operation of the engine is shown in FIG. 15. Here fresh charges of air entrained with fuel are entering cylinders 14b and 16a, while the compressed charges in cylinders 14a and 16b are igniting to begin the power stroke of the pistons in said cylinders 14a and 16b. As has above been indicated, this will produce compression strokes of the pistons in cylinders 14b and 16a. Concurrently therewith, the power stroke of the pistons in cylinders 10b and 12a is proceeding, as is the compression stroke of the pistons in opposed cylinders 10a and 12b.

FIG. 16 shows the next stage in the operation of the engine, wherein the pistons in cylinders 10a and 12b are shown approaching, but not reaching, the end of their respective power strokes. The exhaust ports have been opened, but not the inlet ports. Accordingly, the combustion gases are now escaping from these cylinders, but they are not fully expelled therefrom until the pistons reach the end of their power stroke and thereby open the inlet ports to admit a fresh charge of air entrained with fuel. It is this fresh charge that fully exhaust these two cylinders of their combustion gases. The pistons in opposed cylinders 10b and 12a are concurrently approaching, but not reaching, the end of their compression stroke. Also, the power stroke of the pistons in cylinders 14a and 16b is continuing, while the compression stroke of the pistons in cylinders 14b and 16a is concurrently proceeding. When the pistons 10a and 12b reach the end of their power stroke, they and all of the other pistons shown in FIG. 16 will occupy the same relative positions as they are shown to occupy in FIG. 12, thereby concluding one complete cycle and commencing the next.

It will be seen, particularly in FIGS. 7 through 10 of the drawing, that the crankshaft is shown in four successive angular positions, spaced 90.degree. apart. At each angular position of the crankshaft two of the eight power cylinders are engaged in their respective power strokes. It follows that, for every revolution of the crankshaft, four separate and successive power thrusts are delivered to it, each delivered by two separate and spaced power pistons situated 180 .degree. apart. This arrangement makes for a nicely balanced engine with smooth operation and a substantially continuous flow of power.

The relatively long stroke--small bore design provides a relatively high torque output at a relatively low r.p.m. The length of the power piston stroke is twice the length of the crankshaft throw (diameter of the circular path described by the crankpins). This is effected through the use of the piston rod of the air charging cylinder as a lever between the piston rods of the power cylinders and the crankshaft. Accordingly, the power pistons apply twice the leverage upon the crankshaft which they would apply if connected directly thereto. This is clearly apparent from FIGS. 7 through 11 of the drawing.

The long stroke small bore design also provides an improved surface (piston area) to cylinder volume ratio which, when combined with the longer piston dwell during initial combustion stages, lengthens time in milliseconds before quenching begins, to promote more complete combustion during the work stroke.

This will be evident from a study of FIGS. 7 through 11 of the drawing. It will there be seen that opposed power pistons 10d and 10f are not always the same distance apart. When their respective piston rods 10e and 10g are axially aligned, as in FIGS. 7 and 9, the pistons are at their extreme outer positions relative to each other. When these piston rods are inclined toward each other at the smallest angle which the geometry of the system will permit, as in FIGS. 8 and 10, the pistons are at their extreme inner positions relative to each other.

It will also be understood that these opposed power pistons travel toward and away from each other concurrently with their joint movement in the same direction. Thus, when the crankshaft rotates 90.degree. from its FIG. 7 to its FIG. 8 position, the power pistons will move toward each other at the same time that they are both moving leftwardly. Stated differently, power piston 10d will move leftwardly at a slower speed than piston 10f, so that in relation to each other the two pistons will be moving toward each other.

By the same token, when the crankshaft rotates an additional 90 .degree., this time from its FIG. 8 to its FIG. 9 position, the two power pistons 10d and 10f will move away from each other concurrently with their continued joint movement leftwardly. When the crankshaft rotates a further 90 .degree. from its FIG. 9 to its FIG. 10 position, the power pistons 10d and 10f will move toward each other at the same time that they are both moving rightwardly. When the crankshaft rotates an additional 90 .degree. from its FIG. 10 to its FIG. 7 position, completing a 360 .degree. revolution, the said power pistons will move away from each other concurrently with their joint continued movement toward the right.

As has above been indicated, one of the consequences of this relationship between the power pistons is that longer piston dwell is attained during initial combustion stages and hence more complete combustion.

The foregoing is illustrative of a preferred form of the invention, and it will of course be understood that the invention encompasses extensive design modifications within the broad scope of the appended claims. For example, what is shown is an air-cooled engine with fins 24 serving as heat exchangers for the power cylinders and fins 72 serving as heat exchangers for the air charging cylinders. Obviously the invention is equally applicable to a liquid-cooled engine. Similarily, the power pistons are shown formed with a protuberance 74 for enhanced distribution of the air-fuel mixture and more uniform combustion thereof. Clearly, modifications in this design, and even the omission of any such protuberance, would fall within the range and scope of the principles of this invention and the appended claims. Nor is the invention limited to the particular dimensions and proportions shown in the drawing. This is particularly true of the stroke-bore ratio and the lever ratios shown in the drawing.

Claims

What is claimed is:

1. In a lever-type internal combustion engine, the combination of:

a. a crankshaft,

b. a plurality of power cylinders and air charging cylinders communicating with said power cylinders,

c. said power and air charging cylinders being each provided with a piston and a piston rod pivotally connected at its inner end with said piston, and

d. a lever system whereby the power cylinder pistons and piston rods drive the crankshaft,

e. said lever system consisting of the piston rods of the power and air charging cylinders pivotally interconnected at their outer ends,

f. the piston rods of the air charging pistons being also operatively connected intermediate their ends to the crankshaft,

g. whereby said air charging cylinder piston rods function as second class levers between the power cylinder piston rods and the crankshaft,

h. The pivotal connection between the piston and inner end of the piston rod of the air charging cylinders functioning as the fulcrum of the lever,

i. the pivotal connection between the outer end of the piston rod of the air charging cylinders and the outer end of the piston rod of the power cylinders functioning as the force applying point of the lever, and

j. the operative connection between the crankshaft and the piston rod of the air charging cylinders functioning as the load applying point of the lever.

2. A lever-type internal combustion engine in accordance with claim 1, wherein:

a. the power cylinders are arranged in linearly opposed pairs

b. to enable each cylinder of each pair of power cylinders to absorb the inertial thrust of the piston and piston rod of the other cylinder.

3. A lever-type internal combustion engine in accordance with claim 1, wherein:

a. one air charging cylinder is provided for two power cylinders,

b. the volumetric capacity of each said air charging cylinder being sufficient to concurrently scavenge and recharge both power cylinders.

4. A lever-type internal combustion engine in accordance with claim 3, wherein:

a. the power cylinders are provided with inlet and outlet ports, and

b. means for concurrently opening both ports,

c. whereby the power cylinders may concurrently be scavenged and recharged by the air charging cylinders with which they are in communication.

5. In a lever-type internal combustion engine, the combination of:

a. a plurality of power cylinders arranged in pairs,

b. each pair of power cylinders being coaxially aligned in opposed positions,

c. pistons in each pair of opposed power cylinders,

d. piston rods pivotally connected at their respective inner ends to said pistons,

e. said piston rods being pivotally connected at their outer ends to each other,

f. a plurality of air charging cylinders,

g. there being one air charging cylinder for each pair of opposed power cylinders,

h. a piston in each said charging cylinder,

i. a piston rod pivotally connected at its inner end to each said charging cylinder piston,

j. the outer end of the piston rod of each charging cylinder being pivotally connected to the pivotally connected outer ends of the piston rods of the corresponding pair of opposed power cylinders, and

k. a crankshaft having a plurality of crankpins, one for each air charging cylinder,

l. the piston rod of each said charging cylinder being operatively connected intermediate its inner and outer ends to one of the crankpins of the crankshaft,

m. whereby the piston rod of each said charging cylinder functions as a lever of the second class between the piston rods of the corresponding pair of opposed power cylinders and the crankshaft,

n. the pivotal connection at the inner end of the piston rod of each charging cylinder comprising the fulcrum of the lever,

o. the pivotal connection at the outer end of the piston rod of each charging cylinder being the point at which force is applied to the lever by the piston rods of the pair of opposed power cylinders,

p. The operative connection intermediate the inner and outer ends of the piston rod of each charging cylinder being the point of applied load between the lever and the corresponding crankshaft pin.

6. A lever-type internal combustion engine in accordance with claim 5, wherein:

a. there are four pairs of opposed power cylinders, and

b. four air charging cylinders,

c. the four pairs of opposed power cylinders being arranged in parallel side-by-side relationship in a first common plane,

d. the four air charging cylinders being arranged in parallel side-by-side relationship in a second common plane,

e. the crankshaft being also disposed in said second plane as well as in a third plane,

f. the first and third planes being parallel to each other and perpendicular to the second plane.

7. A lever-type internal combustion engine in accordance with claim 5, wherein:

a. the first plane in which the power cylinders are disposed and the third plane in which the crankshaft is disposed are horizontal, and

b. the second plane in which the charging cylinders and crankshaft are disposed is vertical.

8. A lever-type internal combustion engine in accordance with claim 5, wherein:

a. the stroke of the pistons of the power cylinders is relatively long, and

b. the bore of said power cylinders is relatively small,

c. such that the length of the stroke exceeds the diameter of the bore.

9. A lever-type internal combustion engine in accordance with claim 5, wherein:

a. each air charging cylinder communicates with two power cylinders,

b. the volumetric air charging capacity of each said charging cylinder being sufficient for concurrent scavenging and recharging of the two power cylinders with which it communicates.

10. A lever-type internal combustion engine in accordance with claim 5, wherein:

a. the power cylinders are provided with inlet and outlet ports,

b. the pistons within said power cylinders being adapted to open and close said inlet and outlet ports,

c. and being adapted to open both ports concurrently to enable the communicating air charging cylinder to concurrently scavenge and recharge the power cylinders,

d. said pistons being also adapted to close both ports for the compression and power strokes of said power cylinders.