US3584610A

US3584610A - Internal combustion engine

Info

Publication number: US3584610A
Application number: US879734A
Authority: US
Inventors: Kilburn I Porter
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-11-25
Filing date: 1969-11-25
Publication date: 1971-06-15
Anticipated expiration: 1988-06-15

Abstract

A radial internal combustion engine comprising pairs of diametrally opposed cylinders, the pistons of which act on a central cam to rotate a shaft. Each piston head carries at least one intake or exhaust valve actuated by the same cam.

Description

9 1 1 Unite tates atent 1 1 3,584,610

[72] Inventor Kilburn I. Porter 1,115,477 11/1914 Austin 1. 123/47 A R0. Box 547,Evanst0n. Wye. 82930 1.765.237 6/1930 King 123/55 A [21] APPLNO, 879,734 1,830 O46 11/1931 White M l23/55 AA Filed 1969 FOREIGN PATENTS {451 Paemed 1971 354,535 7/1905 France 123/44 E 432,114 9/1911 France l l l23/47A France v l v i E 9 Claims, 9 Drawing Figs. Primary ExaminerWendell E. Burns 52 U.S. c1 l23/55AA, AmmekHolcombe, wetheri Brisebis 123/44 E, 123/47 R, 123/56 C [51] Int. Cl ..F02b 75/22, F011 11/00, F02b 75/04 [50] Field of Search l23/47,47

A, 47 AA, 47 AB, 55 AA, 44 15,56 C

ABSTRACT: A radial internal combustion engine comprising [56] References cited pairs of diametrally opposed cylinders, the pistons of which UNITED STATES PATENTS act on a central cam to rotate a shaft. Each piston head carries 679,876 8/1901 Blake v. 123/47 at least one intake or exhaust valve actuated by the same cam.

/6 3/ za I9 27 5 PATENTEU Jum 5 m SHKET 1 Ci PATENTED JUN] 51% SHEET 2 [IF 2 m, AlHI INTERNAL COMBUSTION ENGINE SUMMARY OF THE INVENTION The invention relates to an internal combustion engine having an even umber of cylinders and pistons arranged in a circle, with the pistons in diametrically opposed pairs, and the pistons of each pair attached to each other.

Internal combustion engines of this type a shown in US. Pat. Nos. 1,765,237 and 1,830,046. These engines comprise cylinders and pistons arranged in a circle and the pistons reciprocate in the plane of that circle. All the pistons are connected to drive a three-lobe cam fixed to a rotary shaft. This cam converts the reciprocating movement of the pistons into rotary motion. The intake and exhaust valves of the combustion chambers formed by the cylinders and pistons extend through the walls of the cylinders and are actuated by separate rod and lever arrangements.

In another known type of internal combustion engine shown in US. Pat. No. 679,876 and having cylinders and pistons arranged in a circle, the reciprocating movement of the pistons is converted into rotary motion by means of a crank. The exhaust valves extend through the pistons and are actuated by a cam mounted on the same shaft as the piston rods and revolving with the crank. Thus, both a crank and a revolving cam are required for four cylinders with valved pistons arranged in a circle.

It is the object of the present invention to provide an internal combustion engine with an even number of cylinders and pistons arranged in a circle, which uses a single multilobe cam both for the conversion of the reciprocating movement of all the pistons into a rotary motion and for the actuation of either the intake valves or the exhaust valves extending axially through the pistons.

It is a further object of the invention to provide a am for said internal combustion engine having two cam surfaces, which cooperate with a pair of rollers mounted on the bottom of each piston so that reciprocation of the pistons causes rotation of the cam, and another cam surface which actuates the valves extending through the pistons.

Yet another object of the invention is to provide a multilobe cam for an internal combustion engine having an even number of cylinders and pistons arranged in a circle and in which both the intake and the exhaust valves extend through the pistons.

Other objects will be apparent from the following description of two embodiments of the invention, with reference to the accompanying drawings, in which:

FIG. 1 is a diagrammatic elevational view of an internal combustion engine according to the invention with one end of the cylinder block broken away to expose the pistons;

FIG. 2 is a sectional view taken along the line 11-11 of FIG. 1;

FIG. 3 is a fragmentary sectional view taken along the line 111-111 of FIG. 1;

FIG. 4 is a top view of a three-lobe cam used in the internal combustion engine according to the invention;

FIG. 5 is a side view ofthe cam of FIG. 4;

FIGS. 6 and 7 are detailed views showing two connected pistons used in the internal combustion engine according to the invention;

FIG. 8 is a fragmentary view of a piston for a second embodiment of the invention; and

FIG. 9 is a side view of a three-lobe cam for the second embodiment of the invention.

FIG. 1 shows an internal combustion engine according to the invention comprising a cylinder block l having four

cylinders

2, 3, 4, 5. Each cylinder is provided with an

exhaust port

6, 7, 8, 9 for the burned gas. The valves for these ports are not shown since they are of a conventional construction well known to those skilled in the art. In each

cylinder

2, 3, 4, 5, a

piston

12, 13, 14, is mounted for reciprocating movement and closes one end of a combustion chamber in that cylinder. The combustion chambers are sealed by piston rings 16. The

opposed pistons

12, 14 and 13, 15 of each pair are connected to each other by slotted plate members, as shown in FIGS. 6 and 7 for

pistons

13, 15 which are connected by

plate members

17 and 19 attached to the pistons by

pins

21 and 23 which extend through the pistons, transversely to the axes thereof. Pistons 12 and 14 are connected by slotted plate members 18 and 20 (FIGS. 1 and 3) in the same manner as

pistons

13 and 15. However, the

plate members

18 and 20 are further from the plane comprising the axes of all the pistons than the

plate members

17 and 19 ofpistons 13 and 15 (FIGS. 2 and 3). Two

rollers

25 and 27, 26 and 28, 29 and 31, 30 (the second roller of the latter pair is not shown) are journaled on each of the

pins

21, 22, 23, 24 by means of which the plate members are attached to the pistons.

Intake valves extending coaxially through the pistons comprise a valve stem 32 carrying a slotted guide member 33 and a plate 34. The intake valves also comprise a valve disc 36 on the outer end of the valve stem 32 and a valve lifter 37 on the inner end of the guide member 33. The valve stems 32 may consist of two parts screwed together at 38 in order that the valves can be inserted in the pistons and a spring 39 can be mounted between the plate 34 and the inner surface of the piston coaxially of the valve stem 32 so that the spring 39 biases the intake valve toward a closed position.

A three-lobe cam 40 is fixed at its center to a rotary shaft 41 in the cylinder block 1. This rotary shaft extends through the cam 40 and through

slots

42, 43, 44, 45 in the

plate members

18, 17, 20, 19 and is journaled in the cylinder block (not shown in detail), and at least one end of the rotary shaft 41 projects out of the cylinder block. As shown in FIGS. 2 and 3, the three-lobe cam lies between the

plate members

17, 18 and 19, 20 and rotates with the rotary shaft 41.

At first, movement of the pistons .and the three-1obe cam will be described without consideration of the function of the valves. When piston 14 moves inward (i.e. when the volume of the corresponding combustion chamber increases) piston 15 also moves inward. Pistons 12 and 13 simultaneously move outward and the three-lobe cam 40 rotates in a clockwise direction (FIG. 1). The rollers of all the pistons are always in contact with

first cam surfaces

46 and 47 of the three-lobe cam 40. The position of these cam surfaces can be seen best in FIGS. 3, 4 and 5. When the

pistons

14 and 15 move further inward, the

rollers

29 and 31 of piston 15 reach the lowest point on the first cam surfaces 46, 47 (i.e. the point on the first cam surfaces nearest the rotary shaft 41) after rotation of the three-lobe cam 40 through a small angle and the piston 15 is in the so-called crank-end dead center position. At this moment the

rollers

25 and 27 of piston 13 are in contact with the highest point on the three-lobe cam, which lies opposite said lowest point, and the piston 13 is in the so-called head-end dead center position. Pistons l3 and 15 now reverse their direction of movement, and piston 13 moves inward and piston 15 moves outward, while the rollers of said pistons remain in contact with the

first cam surfaces

46, 47 of the three-lobe cam 40. Pistons 12 and 14 reciprocate correspondingly. Consequently, the reciprocating movement of the

pistons

12, 13, 14, 15 is converted into rotary motion of the shaft 41 by the three-1obe cam 40.

As mentioned above, the

cylinders

2, 3, 4, 5 are provided with

exhaust ports

6, 7, 8, 9, respectively, for the burned gas. The fuel to be compressed and to be burned is supplied through supply ports 10 and 11 in the cylinder block 1. A blower may be used to produce an excess pressure in the crankcase, i.e. in the space surrounding the three-lobe cam 40. (Details of the fuel supply and the supply ports are not shown Since they are known to those skilled in the art.) The above-described intake valves extend through the

pistons

12, 13, 14, 15 to admit fuel from the space surrounding the threelobe cam tothe combustion chambers. Those intake valves are normally held closed by the springs 39 and will be opened only to admit fuel in a manner which will be described later. After that the valve will be closed again and the fuel is compressed by outward movement of the piston and then ignited by a spark plug (not shown). The explosion drives the piston inward and the corresponding exhaust port in the cylinder is opened so that the burned gas flows out of the combustion chamber. At the same time, or a short time after that, fuel is forced into the combustion chamber again.

The three-lobe cam 40 has a second cam surface 48 between each two lobes which lies axially between the first cam surfaces 46 and 47, as seen in FIG. 5. The radius of curvature of the second cam surface 48 is larger than that of the first cam surfaces 46, 47 (FIG. 4). The second cam surface is also shorter than the first cam surfaces and merges into those first cam surfaces at the end of the lobes (FIGS. 4 and 5). This second cam surface serves to actuate the intake valves by sliding the valve lifter 37, the slotted guide piece 33, the valve stem 32 and the valve disc 36 outward. This will be described in connection with an operating cycle of piston 13.

In FIG. 1, piston 13 is nearly in head-end dead center position, just before ignition of the compressed fuel. This ignition occurs when the

rollers

25, 27 are in contact with the highest point on the three-lobe cam 40. The explosion drives the piston inward and the

rollers

25, 27 are urged against the first cam surfaces 46, 47, so that the three-lobe cam is rotated in a clockwise direction. Piston 13 then reaches the position shown in FIG. I for the piston 14. When piston 13 moves further inward, the valve lifter 37 contacts the second cam surface 48 of the threelobe cam and the valve lifter, the valve stem 32 and the valve disc 36 are moved outward against the tension of the spring 39 so that the intake valve begins to open, as shown in FIG. 1 for pistons and 12, and in FIG. 2 for piston 15. Now fuel flows into the combustion chamber from the space surrounding the three-lobe cam 40. After further rotary motion the valve lifter 37 reaches the end of he second cam surface 48 and is no longer in contact with the three-lobe cam, and the spring 39 closes the intake valve. Outward movement of the piston then compresses the fuel in the combustion chamber and thus prepares it for ignition.

After the explosion the piston moves radially inward and the exhaust port opens, as shown for port 9 in cylinder 5, thereby releasing the burned gas.

In a practical example of the embodiment described having a 3-inch piston stroke the rollers on the piston have a radius of 1.5 inches and the highest points on the three-lobe cam are tangent to a circle having a radius of 4.5 inches. The radius of curvature at the highest points of the three-lobe cam is 0.75 inch, and the radius of curvature of the first cam surfaces is 3 inches between each two lobes of the cam, the centers of the latter curvatures lie on the same circle as the highest points of the cam. In another practical example having a 2-inch piston stroke, the rollers have a radius of 1 inch, the highest points of the cam lie on a circle having a radius of 3 inches, the radius of curvature at the highest points is 0.5 inch, and the radius of curvature of the first cam surfaces between each two lobes is 2 inches. Consequently, the ratio of the magnitude of the stroke to the radius of the rollers to the radius of the circle of the highest points of the cam to the radius of curvature at the highest points on the lobes to the radius of curvature of the first cam surfaces between each two lobes may be x to x/2 to 1.5x to x/4 to x.

In the first embodiment illustrated the lowest point on the second cam surface 48 lies exactly halfway between each two lobes of the three-lobe cam, and both ends of the second cam surface 48 merge into the first cam surfaces 46, 47 at the same distance from said lowest point (FIGS. 4 and 5). Therefore, the intake valve opens during the inward movement of the piston and is kept open at the crank-end dead center position and during a part of the outward movement. The exhaust port in the cylinder is opened during part of the time the intake valve is open. Therefore, the engine operates substantially as a two-stroke internal combustion engine. However, it is possible to locate the second cam surface away from the midpoint between the highest points of each two lobes, so that the valve lifter first contacts the second cam surface at the crank-end dead center position of the piston or contacts it even later. The second cam surface can be adjusted so that it will not open the intake valve extending through the piston until the exhaust port in the cylinder is closed again. The operation will then resemble that of a four-stroke internal combustion engine.

In the foregoing description the intake valves extend through the pistons while the exhaust valves are in the cylinder. It is also possible to locate the intake valves in the cylinders while the exhaust valves extend through the pistons. Then the second cam surfaces have to open and to close the exhaust valves during the predetermined period and in correct relation to the function of the intake valves.

Furthermore, both intake and exhaust valves may be arranged to extend axially through the pistons. FIG. 8 is a fragmentary view of a piston with intake valve 49 and exhaust valve 56). The remainder of the piston is similar to the pistons if FIGS. 1-3, 6 and 7. The intake and exhaust valves 49, 50 extending through the piston are actuated by a three-lobe cam with a second cam surface 48' and a third cam surface 51. The surface between two lobes of this three-lobe cam is shown in FIG. 9.

The rollers of the piston run on the first cam surfaces 46 and 47'. The third cam surface 51 opens the exhaust valve 50 to release burned gas while the inlet valve 49 is kept closed by the tension of a spring. After further rotation of the three-lobe cam the intake valve is closed and compression of the fuel begins.

When both intake and exhaust valves extend through the piston, the crankcase must be divided into two sealed chambers, e.g. by a membrane, to separate the burned gas flowing through the exhaust valve from the fuel.

To control the opening of the intake and exhaust valves when both extend through the piston (FIG. 8) the second and third cam surfaces may begin and/or end at different points or at the same points of the three-lobe cam and they may have the same or different radii of curvature.

In the illustrated embodiments each piston has two rollers and there are two first cam surfaces on the three-lobe cam for those rollers. However, the pistons may have only one roller or more than two rollers, and the three-lobe cam may have a corresponding number of first cam surfaces. Furthermore, the engine according to the invention may comprise only two pistons and cylinders or more than four pistons and cylinders.

What I claim is:

1. In an internal combustion engine comprising a cylinder block, an even number of cylinders in said block arranged in a circle, said cylinders being positioned in diametrically opposed pairs, a piston in each cylinder, means connecting the pistons of each pair to each other, a shaft rotatably mounted in said block and carrying a multilobe cam, and drive means carried by each piston in contact with said earn, the improvement according to which said piston is provided with a valve in its head and a valve stem extending from said valve toward said cam, and said cam has at last two cam surfaces, one of which is in contact with said drive means so that said cam is driven by said pistons, and one of which is in contact with said valve stems to actuate said valves.

2. Internal combustion engine according to claim 1 in which the valves in the piston heads are intake valves and exhaust valves are located in the walls of the cylinders.

3. Internal combustion engine according to claim 1 in which said drive means comprises a pair of rollers carried by each piston and spaced axially of said shaft, and said cam has two correspondingly spaced cam surfaces in contact with said rollers and embracing a third surface in contact with said valve stems.

4. Internal combustion engine according to claim 1 in which both the intake and exhaust valves for each cylinder extend through the piston in that cylinder, and said cam comprises a first cam surface which contacts the drive means carried by pistons, a second cam surface which actuates the intake valves, and a third cam surface which actuates the exhaust valves, said second and third cam surfaces being axially spaced from each other.

which the ratio between the stroke of said pistons, the radius of said circle, and the radius of curvature of the cam surfaces between said lobes is l:l.5:l.

8. An internal combustion engine as claimed in claim 7 in which the ratio between the stroke of said pistons and the radius of curvature at the high point on each lobe is 4:1.

9. Internal combustion engine as claimed in claim 8 in which the ratio between the stroke of said pistons and the radius of the rollers carried by said pistons is 2: l.

Claims

1. In an internal combustion engine comprising a cylinder block, an even number of cylinders in said block arranged in a circle, said cylinders being positioned in diametrically opposed pairs, a piston in each cylinder, means connecting the pistons of each pair to each other, a shaft rotatably mounted in said block and carrying a multilobe cam, and drive means carried by each piston in contact with said cam, the improvement according to which said piston is provided with a valve in its head and a valve stem extending from said valve toward said cam, and said cam has at last two cam surfaces, one of which is in contact with said drive means so that said cam is driven by said pistons, and one of which is in contact with said valve stems to actuate said valves.

5. Internal combustion engine according to claim 4 comprising two first cam surfaces axially spaced from each other by the second and third cam surfaces and said drive means comprises rollers mounted on the pistons in contact with said first cam surfaces.

6. An internal combustion engine as claimed in claim 1 comprising four cylinders in which said cam has three identical equally spaced lobes, the tips of which are tangent to a single circle.

7. An internal combustion engine as claimed in claim 6 in which the ratio between the stroke of said pistons, the radius of said circle, and the radius of curvature of the cam surfaces between said lobes is 1:1.5:1.

9. Internal combustion engine as claimed in claim 8 in which the ratio between the stroke of said pistons and the radius of the rollers carried by said pistons is 2:1.