GB2607909A

GB2607909A - BB11 Internal combustion engine

Info

Publication number: GB2607909A
Application number: GB2108510.5A
Authority: GB
Inventors: Robert Evans Peter
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-06-15
Filing date: 2021-06-15
Publication date: 2022-12-21
Also published as: GB202108510D0

Abstract

An internal combustion engine comprising a cylinder and at least one reciprocating piston 5 therein, a chamber 11 for receiving a fuel/gas mixture, the piston comprising a piston head 7 and 5 a piston rod 12 extending from the piston head, wherein the engine further comprises a continuous cam track 34 rotatable about an axis, said piston rod 12 comprising a cam follower 29,30, the continuous cam surface rotationally connected to a rotor 36. In use, reciprocation of the piston rod causes the continuous cam surface to rotate about the axis rotating the rotor. There may also be a timed guide apparatus using bearings 20 to 27 to guide the piston rod. The cam track or cam follower could be adjustable, prolonging or shortening the time on a power stroke, both to provide more torque, and facilitate a complete burn.

Description

BB11 INTERNAL COMBUSTION ENGINE The present invention relates to an internal combustion engine.

Internal combustion engines (ICEs) are well known.

Many improvements have been made to ICEs since its commercialization by Etienne Lenoir in the mid nineteenth century and the first modern internal combustion engine by Nicolaus Otto in 1876.

An ICE generally comprises a plurality of pistons each arranged in a respective cylinder. Each piston comprises a piston head and a connection rod. One end of the connection rod is movably fixed to the piston head with a pin connection and at the other to a crank shaft. The crank shaft is in turn connected to a centrally mounted drive shaft. A cylinder head is provided to enclose the cylinders to define a chamber. A plurality of valves are provided in to the cylinder head to allow a pre-defined quantity of an oxidizer, such as air and a fuel, such as gasoline or diesel, into the chamber. The valves are closed and the piston cycles to compress the air/fuel mix in the chamber. A spark plug or glow plug may be used to ignite and combust the compressed air/fuel mixture which releases potential energy held in the form of chemical energy in the fuel into heat energy, which dissipates into an expansion of the air within the chamber. The expansion of the air within the chamber pushes the piston along the cylinder. Kinetic energy in the movement of the piston head passes through the connection rod to the crank shaft rotating the drive shaft.

There are two main types of internal combustion engine: four stroke and two stroke.

A four stroke ICE utilises continuous rotation of the -2 -drive shaft in a cycle which comprises an intake stroke, in which the piston head starts at top dead centre (0 degrees) moves along the cylinder away from the cylinder head in concert with the crank shaft. Air and fuel mix is drawn in through an open poppet valve into the chamber until the piston reaches bottom dead centre (180 degrees). The poppet valve is closed and the piston head moves upwardly in a compression stroke, compressing the air and fuel mix in the chamber to top dead centre (360 degrees).

A spark plug or glow plug may be used to ignite and combust the compressed air/fuel mixture. The resultant expansion of the air/fuel mix within the chamber pushes the piston along the cylinder (bottom dead centre (540 degrees)). The poppet valve opens and the continued motion of the crank shaft with the drive shaft pushes the piston head towards the cylinder head pushing the exhausted air and spent fuel contaminates through the valve into an exhaust system. The drive shaft and crank fixed thereto have undergone 720 degrees of rotation in one four-stroke cycle.

The two-stroke ICE has a 360 degree cycle and uses fewer parts than a four-stroke engine. The two-stroke ICE does not have separate poppet valves, instead using an exhaust valve located in the cylinder wall close to the cylinder head and an inlet port located in the cylinder wall further from the cylinder head. The two-stroke cycle comprises the piston head passing the inlet port at approximately 90 degrees from top dead centre. Between 90 degrees and bottom dead centre (180 degrees), movement of the piston head sucks a fuel and air mixture into the chamber through a non-return valve. Further movement of the piston head between bottom dead centre (180 degrees) and top dead centre compresses the air/fuel mixture in the chamber, at which point a spark from a spark plug or heat from a glow plug ignites the air fuel mixture. Combustion of the air fuel mixture induces expansion, pushing the piston down. Exhaust gases pass out of the chamber through the exhaust port into an exhaust system. Two stroke ICEs generally use a single cylinder, with a counter-weighted crank, rotating around an axis common with a drive rotor. The fuel may be any energy bearing fluid, such as hydrocarbon fuel, such as gasoline, diesel, kerosene or 10 may be hydrogen or nitrous oxide.

There are many variations and improvements to the ICE, such as six-stroke piston engines and the Wankel rotary engines.

ICEs have become extremely important in modern life.

However, they exhaust carbon dioxide, various gases and particulates containing carbon and hydrocarbon chains and other noxious gases which are not good for the environment and potentially add to global warming. One problem is that ICEs are not very efficient. ICEs generally run at less than 50% efficiency. This is in part due to difficulties with getting the air fuel mixture into the chamber and to burn completely. Another problem is that there are inefficiencies in transferring longitudinal motion of the pistons into rotational motion in a drive shaft.

The inventor has noted that in conventional ICEs using a crank shaft, piston rods are not always in direct alignment with the longitudinal motion of the piston head. This may induce wear between the piston head and the cylinder and thus need plentiful oil lubrication. This may also induce wear in any piston ring or other sealing element between the piston head and cylinder. Once worn, lubricating oil may pass between the piston head and -4 -cylinder wall into the chamber, whereupon the oil burns incompletely and is emitted in the exhaust which is highly undesirable for the environment and further impact global warming.

The inventor has also noted with a conventional ICE, the piston of a single cylinder may move at different rates through the cycle, faster on the downward stroke after combustion and slower on the return stroke. A well-known solution to this is to increase the number of cylinders and balance the cylinders by running them out of phase with the first.

The inventor has also noted that with a conventional ICE, changing timing to achieve an efficient and complete burn of air/fuel mixture in the chamber and to convert heat created in the combustion of the air/fuel mixture into useful rotation of the drive shaft is not easy for all parts of the cycle.

In accordance with the present invention, there is provided an internal combustion engine comprising a cylinder and at least one reciprocating piston therein, a chamber for receiving a fuel and oxidizer mixture, the piston comprising a piston head and a piston rod extending from the piston head, characterised in that the internal combustion engine further comprises a continuous cam track rotatable about an axis, said piston rod comprising a cam follower, the continuous cam track rotationally connected to a rotor. In use, reciprocation of the piston rod moves the follower back and forth causing the continuous cam surface to rotate about the axis rotating the rotor. An internal combustion engine of the type disclosed herein is known as BB11TM internal combustion engine.

Optionally, the piston rod is rigidly fixed to the -5-piston head. Optionally, the piston rod is movably fixed to the piston rod, to allow a small degree of rotation of the piston rod with respect to the piston head.

The present invention also provides an internal combustion engine comprising a cylinder and at least one reciprocating piston therein, a chamber for a fuel and gas mixture to combust, the piston comprising a piston head and a piston rod extending from the piston head, wherein the piston rod is either rigidly fixed to the piston or integral with the piston.

Optionally, the rotor is arranged on said axis. Optionally, the continuous cam track is a continuous loop about 360 degrees. Optionally, the continuous cam track is a continuous loop about 720 degrees in the form of a figure of eight. Optionally, the continuous cam track comprises an inner cam surface upon which at least a part of the cam follower is arranged. Optionally, the continuous cam track comprises an outer cam surface upon which at least a part of the cam follower is arranged. Optionally, the inner and outer cam surfaces are substantially parallel and optionally, a part of the cam follower follows the inner cam surface and another part of the cam follower follows the outer cam surface, translating both outward and inward movement of the piston rod to rotational motion in the continuous cam track. Optionally, the inner and/or outer cam surface has a continuous recess therein to receive and preferably guide the cam follower. Optionally, the at least a part of the cam follower comprises a bearing surface. Optionally, the bearing surface is arranged on a perimeter of a rotating bearing. Optionally, the rotating bearing comprises a ball bearing race. Optionally, the continuous cam track comprises a continuous curve, optionally with -6-sharp changes of direction and shallow changes of direction. Optionally, the sharp changes of direction reflect increase in acceleration of the piston rod. Optionally, shallow changes of direction reflect low acceleration, optionally at high speed. Optionally, the continuous cam track is in a shape, which may be one of: an oval; flattened circle; rectangle having curved corners; a trapezium having curved corners; a parallelogram having curved corners; and an ellipse. It should be noted that by using a different shape of continuous cam track, the piston maybe held for longer or shorter periods of time at various stages in the cycle. This maybe used to inter alia: improve a complete combustion of the air/fuel mixture within the chamber; to obtain a more powerful stroke in the power stroke of the cycle; to obtain a more consistent combustion throughout the power stroke of the cycle; a controlled longer or shorter time for the spent fuel and waste gases to be exhausted from the chamber; a longer or shorter time for piston to move from an inward stroke to an outward stroke, which may be used to obtain a more consistent rotation. The cam follower or cam track can be engineered to wait at TDC or BDC or too proceed on power stroke slower down, then with it returning faster, subject curvature of cam track or shape of the cam follower. This cam track or cam follower could be adjustable, prolonging or shortening the time on the power stroke, both to provide more torque, and facilitate a complete burn.

Optionally, the ICE of the invention comprises a single long stroke piston in a cylinder, with cam followers translating the longitudinal motion of the piston rods to the continuous cam track. Optionally, the internal combustion engine further comprises an opposing piston in -7-said bore of said cylinder, defining a chamber between said piston and opposing piston. The piston stroke may be short compared to the single piston option. Optionally, the opposing piston comprises an opposing piston head and an opposing piston rod with an opposing cam follower. This arrangement may facilitate balancing of forces generated by combustion about the rotor, potentially reducing vibration in the internal combustion engine.

Optionally, the internal combustion engine further comprises a guide apparatus to facilitate guiding the piston or piston rod as it reciprocates and maintains its concentricity with the cylinder. Optionally, the guide apparatus comprises a plurality of bearing wheels. Optionally, the bearing wheels are rotatable about a pin, optionally on a ball race, which may be enclosed or open and may be continuously lubricated. Preferably, each bearing wheel has a first portion which defines a perimeter of a circle which has a radius and a second portion which is less than the radius, referred to herein as a cam wheel.

Optionally, the bearing wheel is also provided with a timing mechanism to ensure the major portion of the bearing wheel is in contact with the piston or piston rod during a first portion of its cycle and not in contact during a second portion of its cycle. Optionally, the second portion of the cycle includes change in direction of said piston head along said cylinder. Optionally, the second portion of the bearing wheel is substantially a cord. Optionally, the timing mechanism comprises a gear wheel arranged on a toothed track. Optionally, the track is linear and arranged along at least a portion of the piston rod. Optionally, the guide apparatus comprises at least a first cam wheel continuously rotating clockwise and a second cam wheel rotating anticlockwise. Optionally, the guide apparatus comprises at least two cam wheels in any plane about the piston or piston rod. Optionally, cam wheels are arranged in at least two planes about the piston or piston rod.

Optionally, the internal combustion engine of the present invention is used in a generator for producing electricity. Optionally, the rotor is distant from said axis, said rotor driven by at least one of: a belt drive; and a gear wheel. Optionally, the continuous cam track is fixed to a drum rotating therewith, the drum having windings thereon for producing electricity from said rotation.

Optionally, the internal combustion engine further comprises a means for balancing the engine, the means comprising a ball track about the continuous cam track and a plurality of free running balls in said ball bearing track.

The present invention also provides a method for taking longitudinal motion produced by a reciprocating piston of an internal combustion engine into rotational motion in a rotor, wherein the internal combustion engine comprises a cylinder and at least one reciprocating piston therein, a chamber for receiving a fuel and gas mixture, the piston comprising a piston head and a piston rod extending from the piston head, the method comprising the steps of guiding the piston rod with a guide apparatus, the internal combustion engine further comprising a continuous cam track rotatable about an axis, said piston rod comprising a cam follower, the continuous cam surface rotationally connected to a rotor. -9-

For a better understanding of the present invention, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a schematic front view of a first embodiment of an internal combustion engine in accordance with the present invention in a first step of operation, with an end of a rotor shown in dashed-line and a guide apparatus in accordance with a second aspect of the present invention, the guide apparatus for guiding a piston of the internal combustion engine; Figure lA is a schematic front view of the internal combustion engine shown in Figure 1, in a second step of operation; Figure 18 is a schematic side view of the internal combustion engine shown in Figure 1; Figure 2A is a schematic view of a second embodiment of a guide apparatus in accordance with a second aspect of the invention, which may be used in any of the internal combustion engines disclosed herein, the guide apparatus in a first step of operation; Figure 28 is a schematic view of the guide apparatus shown in Figure 2A in a second step of operation; Figure 2C is a schematic view of the guide apparatus shown in Figure 2A in a third step of operation; Figure 3 is a schematic view of a third embodiment of a guide apparatus in accordance with the second aspect of the present invention which may be used in any of the internal combustion engines disclosed herein; Figure 3A shows a top view of a bearing surface of the guide apparatus shown in Figure 3; Figure 4 shows a side view of a fourth embodiment of a guide apparatus in accordance with the second aspect of -10-the present invention, showing five sequential steps of operation of the further embodiment of the guide mechanism; Figure 4A shows a side schematic view of a guide apparatus of the apparatus shown in Figure 4, showing five sequential steps of operation of the guide mechanism; Figure 43 shows four further sequential steps of operation of the guide apparatus shown in Figure 4A; Figure 5 is a schematic front view of a second embodiment of an internal combustion engine in accordance 10 with the present invention; Figure 5A is a top plan schematic view of cylinders of the internal combustion engine shown in Figure 5; Figure 53 is a side view of a cam follower of the internal combustion engine shown in Figure 5; Figure 6 is a schematic view of a third embodiment of an internal combustion engine in accordance with the present invention in a first step of operation; Figure 6A is a schematic view of the internal combustion engine shown in Figure 6, in a second step of 20 operation; Figure 68 is a schematic view of an inner cam surface of a can track of the internal combustion engine shown in Figure 6 in a first step of operation; Figure 6C is a schematic view of an outer cam surface 25 of a can track of the internal combustion engine shown in Figure 6 in a second step of operation; Figure 7A shows a schematic view of an internal combustion engine similar to that shown in Figure 1, showing a means for taking power therefrom; Figures 7A to 7D shows a schematic view of an internal combustion engine similar to that shown in Figure 1, each showing a means for taking power therefrom; and -11-Figure 8 is a schematic view of an apparatus to facilitate balance with any internal combustion engine disclosed herein.

Figure 1 shows an internal combustion engine in accordance with the present invention generally identified by reference numeral 1 comprising a cylinder 2, which may be formed from a steel block. Typically, the cylinder 2 would be cast and may be machined internally to produce a smooth internal wall 3 defining a bore 4. The bore 4 defined by the internal wall 3 may have a circular cross-sectional shape, although may be oval, elliptical or any other suitable shape. Two pistons 5 and 6 are arranged opposite each other in the bore 4 of the cylinder 2. Each piston 5 and 6 has substantially the same cross-sectional shape as the cross-sectional shape of the cylinder 2 and are slidably arranged within opposing ends of the bore 4 of the cylinder 2. The pistons 5 and 6 each comprise a piston head portion 7 and 8 and a body portion 9 and 10. Piston rings (not shown) may be arranged in groves (not shown) in the piston body portion 9 and 10 to run along the smooth internal wall 3. The internal wall 3 of the bore 4 and front faces of the piston heads 7 and 8 define a chamber 11. The pistons 5 and 6 are arranged in the bore 4 of the cylinder 2 to stroke inwardly to reduce the volume of the chamber 11 and outwardly to increase the volume of the chamber 11. A proximal end of each piston rod 12 and 13 is fixed to respective piston 5 and 6, optionally, to the piston head 7 and 8. The piston rod 12 and 13 is arranged substantially perpendicular to the face of the piston head 7 and 8. Each piston rod 12 and 13 extends outwardly from each piston head 7 and 8 away from chamber 11, substantially concentrically with the piston body portion -12- 9 and 10 and the wall 3 of the cylinder 2. Each piston rod 12 and 13 may be loosely attached to respective piston 5 and 6 on a pin (not shown), as with conventional conrods used in convention crank shaft arrangements to allow the piston rod to rotate over a few degrees as the crank shaft rotates, or the piston rod 12 and 13 may be securely fixed or made integral with the piston 5 and 6. As shown in Figure 1, the piston rod 12 and 13 is formed integrally with the piston head 7 and 8. Optionally, the piston rod 12 and 13 may be welded, glued, adhered, soldered or otherwise fixed to the piston head 7 and 8 at junction 19. Four openings 14, 15, 16 and 17 are arranged in the cylinder: openings 15 and 16 are inlet openings to allow fuel and air mixture to flow into the chamber 11 and openings 14 and 17 are exhaust openings to allow exhaust gases to flow out of the chamber 11. A rotary valve (not shown) selectively allows the opening and closing of the openings 14, 15, 16 and 17. A spark plug 18 is provided in a threaded opening (not shown) in the wall 3 of the cylinder 2 to provide an ignition for air/fuel mixture in the chamber 11.

The piston rods 12 and 13 are guided longitudinally by a guide apparatus, such as guide apparatus 100 shown in Figures 1 and 1A, guide apparatus 200 shown in Figures 2A to 2C, and guide apparatus 300 shown in Figure 3A to 3C.

The guide apparatus 100 comprises bearings 20 to 27 inter elle facilitate the piston to stroke concentrically within the bore 4 of the static cylinder 2. The bearings 20 to 27 may be arranged at ninety degrees to one another about the piston rod 12, 13. Eight guide bearings 20 to 23 and 24 to 27 are shown guiding each piston rod 12 and 13 respectively. The guide bearings 24 to 27 have an axis of -13-rotation substantially perpendicular to the piston rods 12 and 13 and parallel to the plane of a cam surface 33, 35 of a cam track 34 upon which outer and inner end bearings 29 to 32 run. The cam track 34 is at least one complete loop, shaped such that variations in the speed of pistons and 6 translate to a consistent rotation of a drive shaft 36, as will be explained below. It should be noted that the bearings 20 to 23 and 24 to 27 may be substituted with bushings or other similar means to guide the piston rods 12 and 13, optionally reducing friction between the reciprocating piston rod 12,13 and the static cylinder 2.

Outer and inner end cam followers 29 to 32 are arranged on respective concentric axels on the distal end of each piston rod 12 and 13, with inner cam followers 30 and 31 arranged to run along the inner cam surface 33 of the cam track 34 and the outer cam followers 29 and 32 to run along the outer cam surface 35. The outer and inner cam followers 29 to 32 may be: any suitable bearing, such as a ball bearing race bearing, which may be sealed or exposed and may be of any suitable material, such as iron or iron alloy, such as high-speed steel, Inconel 718, Monel 400; or a bushing made of any suitable material. The cam track 34 is free to rotate relative to and optionally about the cylinder 2. An annular plate 38 (shown in Figure 1 planar to the page) is arranged between the cam track 34 and a hemispherical dome 37. The annular plate 38 has an inner continuous edge welded or otherwise attached to the cam track 34 and an outer edge welded or otherwise attached to an outer perimeter of the hemispherical dome 37, see Figure 1B. A rotor 36 (shown in Figure 1 in dashed line, extending into the page) is rotationally fixed to an inner perimeter of the hemispherical dome 37 and thus -14-rotationally fixed to the cam track 34 at a central rotation point. A side of the hemispherical dome 37 is shown in Figure 1B and shown in Figure 1 as a concave surface extending into the page). The hemispherical dome 37 may be solid, have cut-outs or take the form of an array of curved spokes defining a hemispherical shape or the like.

A circular track 39 is provided about the inner surface of the hemispherical dome 37. The circular track 39 is concentric with the rotor 36 and the axis 45 of rotation of the hemispherical dome 37. Drive bearings 40 to 43 are provided on axels fixed to static lugs (not shown) which are static with respect to the cylinder 2. The drive bearings 40 to 43 inter alia help maintain concentricity of the hemispherical dome 37. The drive bearings 40 to 43 may be any suitable bearings, such as a ball bearing race sandwiched between inner and outer annular bearing surfaces, which may be sealed or exposed and may be of any suitable material, such as iron or iron alloy, such as high-speed steel, Inconel 718, Monel 400; or a bushing made of any suitable material.

Referring to Figure 1, the pistons 5 and 6 are at the end of their outward stroke at Bottom Dead Centre, with cam followers 29, 30, 31 and 32 at the longest chord of the continuous curved cam track 34 and with an air-fuel mix held in the chamber 11. When in use, momentum in rotation of the continuous cam track 34, annular plate 38, hemispherical dome 37, rotor 36 and anything attached to the rotor 36, such as wheels of a motorcycle (not shown) induces continued rotation of the rotor 36, hemispherical dome 37, annular plate 38 and continuous curved cam track 34. Cam followers 29, 30, 31 and 32 follow the continuous -15-curved cam track 34 towards the shortest chord, which moves the pistons 5 and 6 towards each other compressing air-fuel mix in the chamber 11. At Top Dead Centre as shown in Figure 1A, the spark plug 18 is timed to ignite the air fuel mix in the chamber 11, which continues the cycle pushing the pistons 5 and 6 outwardly towards the position shown in Figure 1. Linear outward motion in the piston rods 12 and 13 induces the cam followers 29, 30, 31 and 32 to follow the continuous curved cam track 34 towards the longest chord, translating linear motion in the piston rods 12 and 13 into rotational motion of the continuous cam track 34 about the axis provided by an expansion of the fluids in chamber 11. As the pistons pass the outlet ports 15 and 16, the exhaust gases flow therethrough into an exhaust (not shown). As the pistons 5 and 6 pass the inlet ports 15 and 17, air and fuel mix is blown or allowed to flow through the inlet ports 15 and 16 into the chamber 11. As the cycle repeats, the piston moves towards Top Dead Centre compressing the air fuel mix in the chamber 11. This cycle may be any two-stroke petrol or diesel, 360 degree cycle.

As the inventor observed, the piston rods 12 and 13 may need to be guided by a guide apparatus. Such guide apparatus may be bearings or bushes, as shown in the embodiment of Figure 1. This may be acceptable for some applications of the present invention and may be suitable for smaller engines for use in garden machinery and motorbikes. The inventor has noted that it may be preferable to minimise any energy lost to skin friction or other unnecessary energy losses. The inventor noted that such normal bearings or bushes will have to cope with a rapid change in direction when passing Top Dead Centre and -16-Bottom Bead Centre.

A second embodiment of a guide apparatusis shown in Figures 2A to 2C, the guide apparatus generally identified by reference numeral 200. The guide apparatus 200 is arranged on a piston rod 112 of piston 105. The guide apparatus generally comprises a bearing surface and a timing mechanism. The guide apparatus 200 comprises two pairs of first and second guide parts 101, 102 and 101' (not shown) arranged on opposing sides about piston rod 112. The first pair is identical to the second pair, save being arranged at ninety degrees about the piston rod 112. The first and second guide parts 101, 102 each comprise a gear wheel 103, 104 (teeth not shown), each running in linear toothed tracks 105', 106 arranged along the length of the piston rod 112. The gear wheels 103, 104 are each rotatable about an axel 107, 108, which is fixed to a static part of the internal combustion engine, such as a lug (not shown) extending from the cylinder 2. A resilient bush (not shown) may be provided between the gear wheel 103,104 and the axel 107, 108. A regular cylindrical roller bearing (not shown) or a cam wheel 109, 110 is arranged on axel 107, 108 and rotates in concert with the gear wheel 103, 104. The regular cylindrical roller bearing (not shown) or cam wheel provides a bearing surface to allow linear motion of the piston rod 112 but to inhibit lateral movement of the piston rod 112. The cam wheels 109, 110 each comprises a bearing surface 111, 112 which generally forms a major portion of a circular perimeter and a minor portion 113,114 of lesser diameter than that of the perimeter. The bearing surface 111, 112 is arranged to run along the surface of the piston rod 112, guiding the piston rod 112. The gear wheels 103, 104 runs continuously in the -17-respective toothed track 105', 106 inter alia to facilitate turning the bearing cam in concert with the piston rod to potentially reduce friction and/or as a timing mechanism to ensure the bearing surface is not in contact with the piston rod 12, 13 at TDC and BDC. The cam wheel 109, 110 is sized so as to rotate to a position in which the minor portion 113, 114 of the cam wheel is facing and spaced from and not in contact with the piston rod at Top Dead Centre (Figure 2B) and Bottom Dead Centre (Figure 2C). The gear wheel 103, 104 remains in respective toothed tracks 105', 106 throughout the cycle.

A third embodiment of a guide apparatus is shown in Figures 3, the guide apparatus generally identified by reference numeral 300 is arranged on a piston rod 312 of piston 305. The guide apparatus generally comprises bearing surfaces and a timing mechanism. The guide mechanism is generally similar to that of the guide apparatus 200, save for: the bearing surfaces and timing mechanism, which are no longer on a common axis, but on their own separate axes; and the bearing surface bears against a separate guide cylinder wall rather than the piston rod. The guide apparatus 300 comprises two pairs of first and second guide parts 301, 302 and 301' (not shown) arranged on opposing sides about piston rod 312. The first pair is identical to the second pair, save being arranged at ninety degrees about the piston rod 312, in order to reduce lateral movement of the piston rod 312 in at least two lateral planes. The first and second guide parts 301, 302 each comprise a gear wheel 303, 304 (shown at both TDC and BDC positions), each running in linear toothed tracks 305', 306 arranged along a major portion of the length of the piston rod 312. The gear wheels 303, 304 are each rotatable -18-about an axel 307, 308. A resilient bush (not shown) may be provided between the gear wheel 303,304 and the axel 307, 308. A regular cylindrical roller bearing (not shown) or a cam wheel 309, 310 is arranged on axel 307', 308'.

The axels 307 and 307' are arranged on a dolly (not shown), such that as the gear wheel 303 moves along the linear toothed track 305', the cam wheel 309 moves in concert. The can wheels 309, 310 each comprises a bearing surface 311, 313 forming a major portion of a circular perimeter and a minor portion 314, 315 of lesser diameter than that of the perimeter. The bearing surface 311,313 is arranged to run along the surface of the guide cylinder 312' which is concentric with the piston rod 312, thus guiding the piston 305. The guide cylinder 312' is fixed or formed integrally with the piston head 307' of the piston 305.

The gear wheels 303, 304 run continuously in the respective toothed track 105', 106 inter alia to facilitate turning the bearing cam in concert with the piston rod to potentially reduce friction and/or as a timing mechanism to ensure the bearing surface 311,313 is not in contact with the guide cylinder 312, 313 at TDC and BDC. The cam wheels 309, 310 are optionally sized so as to rotate to a position in which the minor portion of the cam wheel 309,310 is facing and spaced from and not in contact with the guide cylinder 312' at Top Dead Centre (similar to the second embodiment of the guide apparatus shown in Figure 2B) and Bottom Dead Centre (similar to the second embodiment of the guide apparatus shown in Figure 2C). The gear wheel 303, 304 remain in respective toothed tracks 305', 306. It is envisaged that the cam wheels 309, 310 may be arranged inside the guide cylinder 312' and may run along the inside surface of the guide cylinder 312' to -19-guide the piston 305.

A fourth embodiment of a guide apparatus 400 in accordance with a second aspect of the invention is shown in Figures 4. The guide apparatus 400 is arranged on a piston rod 412 of piston 405. The guide apparatus 400 generally comprises bearing surfaces, which may be cam wheels, and a timing mechanism. The guide apparatus is generally similar to that of the guide apparatus 200, save for: having a first cam wheel continuously rotating clockwise and a second cam wheel continuously rotating anti-clockwise, which maintains momentum in the cam wheels and do not require a change of direction of rotation when the piston rod changes. This may be useful in very large ICEs, such as those used in container ships, cargo vessels, cruise ships, oil tankers, liquid gas carriers and the like. Furthermore, at least one bearing surface of a cam wheels is in contact with the piston rod 412 at any time, including at Bottom Dead Centre and Top Dead Centre. As shown in Figure 4A, there are two guide sets 401, 402 of cam wheels 409,409',410,410' at a proximal end of the piston rod 412 and two sets of can wheels at a distal end of the piston rod 412. Guide set 401 will be described. Guide set 401 may use the timing mechanism described below with reference to Figure 4 or may use any other suitable timing mechanism. The guide set 401 comprises: first set of cam wheels 409, 410 for contact with the piston rod 412 during the inward stroke of the piston 405, each set comprising an upper cam wheel 409 rotating clockwise and a lower cam wheel 410 rotating anti-clockwise on an opposing side of the piston rod 412; and a second set of cam wheels 409', 410' for contact with the piston rod 412 during the outward stroke of the piston 405, each set comprising an -20-upper cam wheel 409' rotating anticlockwise and a lower cam wheel 410' rotating clockwise on an opposing side of the piston rod 412. The can wheels 409, 410 each comprises a bearing surface 411, 412 bearing portion of a circular perimeter and a non-bearing portion 413,414 of lesser diameter than that of the perimeter. The bearing surface 411, 412 is arranged to run along the surface of the piston rod 412, guiding the piston rod 412 on the inward stroke towards and at TDC and the non-bearing surface 413,414 to be facing and thus not in contact with the piston rod 412 on the outward stroke of the piston 405. The cam wheels 409', 410' each comprises a bearing surface 411', 412' bearing portion of a circular perimeter and a non-bearing portion 413',414' of lesser diameter than that of the perimeter. The bearing surface 411', 412' is arranged to run along the surface of the piston rod 412, guiding the piston rod 412 on the outward stroke towards and at BDC and the non-bearing surface 413,414 to be facing and thus not in contact with the piston rod 412 on the inward stroke of the piston 405. The cam wheels 409 and 409' may be spaced longitudinally and arranged on separate axels 407 and 407' (as shown) or may be arranged parallel to one another, independently rotatable on a common axel (not shown). Figure 4A and 4B show rotational position of the cam wheels 409, 410 and 409', 410' at various points in a 360 degree cycle of the piston 405: at BDC all cam wheels 409, 410 and 409', 410' are in contact with the piston rod 412; at 45 degrees after BDC first set of cam wheels 409,410 remain in contact with piston rod 412, second set of cam wheels 409',410' loses contact with piston rod 412; at 90 degrees after BDC first set of cam wheels 409,410 -21-remain in contact with piston rod 412, second set of cam wheels 409',410' remain out of contact with piston rod 412; at 135 degrees after BDC first set of cam wheels 409,410 remain in contact with piston rod 412, second set of cam wheels 409',410' remain out of contact with piston rod 412; at 180 degrees after BDC (TDC) first set of cam wheels 409,410 remain in contact with piston rod 412, second set of cam wheels 409',410' gain contact with piston rod 412; at 225 degrees after BDC (TDC) first set of cam wheels 409,410 lose contact with piston rod 412, second set of cam wheels 409',410' remain in contact with piston rod 412; at 270 degrees after BDC (TDC) first set of cam wheels 409,410 remain out of contact with piston rod 412, second set of cam wheels 409',410' remain in contact with piston rod 412; and at 360 degrees after BDC (TDC) first set of cam wheels 409,410 gain contact with piston rod 412, second set of cam wheels 409',410' remain in contact with piston rod 412.

The timing mechanism comprises a gear 403, 404 rotationally fixed to respective first set of cam wheel 409, 410. The gear 403, 404 runs in the respective toothed track 405' to ensure the cam wheel continuously spins in one direction to potentially reduce friction. Gears 403', 404' rotationally fixed to respective cam wheel 409', 410'.

The gear 403', 404' runs in the respective toothed track 406 to ensure the cam wheel continuously spins in an opposing direction to potentially reduce friction.

Figure 5 shows an internal combustion engine 500 which is generally similar to the internal combustion engine shown in Figure 1, save for: four poppet valves 514, 515, 516 and 517 in place of -22-the inlet and outlet openings 14, 15, 16, 17; and the cross-sectional shape of piston heads 507, 508 and cylinder 502 being oval.

As can be seen from a schematic top plan view of Figure 5A, the internal combustion engine 502 comprises two oval cylinders 502, 502' of substantially identical size and shape, arranged perpendicular to one another with a common chamber 511 and a cylinder head 550 between the two oval cylinders 502,502'. The cylinder head 550 provides four lands (two shown) 551, 552 providing room for two inlet opening 553, 554 and two outlet opening (not shown), each having a chamfered perimeter providing a valve seat for poppet valves 514,515,516,517. These poppet valves may be used in a two-stroke or four-stroke cycle.

A further variation in the internal combustion engine shown in Figure 5A is the cam track 534, which is generally similar to cam track 34 shown in Figure 1, save for the cam track 534, which has inner and outer walls 533, 534 defining a channel 536 and a cam follower 529 arranged within the channel 536. The cam follower 529 is shown in more detail in Figure 5B, which shows cylindrical bearing 530 arranged on an axel 560 extending perpendicularly from a distal end of piston rod 512. The can follower 529 has oval shaped washers 561, 562 arranged on the axel 560 either side of the cylindrical bearing 530 to facilitate guiding the cam follower within the track. The cylindrical bearing 530 is slightly smaller in diameter than the width of the channel 536, so that the bearing runs along and is biased against either the outer wall 534 or inner wall 533.

Figure 6 shows a fourth embodiment of an internal combustion engine in accordance with the present invention generally identified by reference numeral 600 comprising a -23-cylinder 602, which may be formed from a steel block. Typically, the cylinder 602 would be cast and may be machined internally to produce a smooth internal wall 603 defining a bore 604. The bore 604 defined by the internal wall 603 may have a circular cross-sectional shape, although may be oval, elliptical or any other suitable shape. Two pistons 605 and 606 are arranged opposite each other in the bore 604 of the cylinder 602. Each piston 605 and 606 has substantially the same cross-sectional shape as the cross-sectional shape of the cylinder 602 and are slidably arranged within opposing ends of the bore 604 of the cylinder 602. The pistons 605 and 606 each comprise a piston head portion 607 and 608. The internal wall 603 of the bore 604 and front faces of the piston heads 607 and 608 define a chamber 611. The pistons 605 and 606 are arranged in the bore 604 of the cylinder 2 to stroke inwardly to reduce the volume of the chamber 611 and outwardly to increase the volume of the chamber 611. A proximal end of each piston rod 612 and 613 is fixed to respective piston 605 and 606, optionally, to the piston head 607 and 608. The piston rod 612 and 613 is arranged substantially perpendicular to the face of the piston head 607 and 608. Each piston rod 612 and 613 extends outwardly from each piston head 607 and 608 away from chamber 611.

Each piston rod 612 and 613 may be loosely attached to respective piston 605 and 606 on a pin (not shown), as with conventional conrods used in convention crank shaft arrangements to allow the piston rod to rotate over a few degrees as the crank shaft rotates, or the piston rod 612 and 613 may be securely fixed or made integral with the piston 605 and 606. As shown in Figure 6, the piston rod 612 and 613 is formed integrally with the piston head 607 -24-and 608.

An inlet opening 615 and outlet opening 616 are arranged in the cylinder 602. The inlet opening 615 allows fuel and air mixture to flow into the chamber 611 and exhaust opening 616 allows exhaust gases to flow out of the chamber 611. A rotary valve 617 selectively allows the opening and closing of the inlet and exhaust openings 615, 616. A spark plug 618 is provided in a threaded opening (not shown) in the wall 603 of the cylinder 602 to provide an ignition for air/fuel mixture in the chamber 611.

The piston rods 612 and 613 are guided longitudinally by a guide apparatus, such as guide apparatus 100 shown in Figures 1 and 1A, guide apparatus 200 shown in Figures 2A to 2C, guide apparatus 300 shown in Figure 3A to 3C and guide apparatus 400 shown in Figure 4 to 4B. The guide apparatus shown in Figure 6 comprises bearings 20 to 27 inter alia facilitate the piston to stroke concentrically within the bore 604 of the static cylinder 602. The guide bearings 624 to 627 have an axis of rotation substantially perpendicular to the piston rods 612 and 613 and parallel to the plane of an inner cam surface 633 and an outer cam surface 635 of a cam track 634. The inner and outer cam surfaces 633 and 635 each have a continuous recess 633', 635' therein, which runs in a figure of eight through 720 degrees, in which outer and inner end bearings 629 to 632 run (only bearings 629 and 630 shown in Fig. 6B and 6C). The cam track 634 is shaped such that variations in the speed of pistons 605 and 606 translate to a consistent rotation of a rotor 636, as will be explained below.

Outer and inner cam followers 29 to 32 are arranged on respective concentric axels 629', 630' on the distal end of each piston rod 612 and 613. The outer and inner -25-cam followers 29 to 32 may be: any suitable bearing, such as a ball bearing race bearing, which may be sealed or exposed and may be of any suitable material, such as iron or iron alloy, such as high-speed steel, Inconel 718, Monel 400; or a bushing made of any suitable material. The cam track 634 is free to rotate relative to and optionally about the cylinder 602. An annular plate 638 (shown in Figure 6 planar to the page) is arranged between the cam track 634 and a hemispherical dome (as for the embodiment shown in Figure 1). The annular plate 638 has an inner continuous edge, shaped and welded or otherwise attached to the cam track 634 and an outer edge welded or otherwise attached to an outer perimeter of the hemispherical dome. The rotor 36 (shown in Figure 1 in dashed line, extending into the page) is rotationally fixed to an inner perimeter of the hemispherical dome and thus rotationally fixed to the cam track 634 at a central rotation point 645.

A circular track is provided about the inner surface of the hemispherical dome. The circular track is concentric with the rotor 636 and the axis 645 of rotation of the hemispherical dome. Drive bearings 640 to 643 are provided on axels fixed to static lugs (not shown) which are static with respect to the cylinder 602.

Referring to Figure 6, the pistons 605 and 606 are at the end of their outward stroke at Bottom Dead Centre, with cam followers 629, 630, 631 and 632 at the longest chord of the continuous curved can track 634 and with an air-fuel mix held in the chamber 611. When in use, momentum in rotation of the continuous can track 634, annular plate 638, hemispherical dome, rotor 636 and anything attached to the rotor 636, such as wheels of a car (not shown) induces continued rotation of the rotor 636, hemispherical -26-dome 637, annular plate 638 and continuous curved can track 634. Cam followers 629, 630, 631 and 632 follow the continuous curved cam track 634 towards the shortest chord, which moves the pistons 605 and 606 towards each other compressing air-fuel mix in the chamber 611. At Top Dead Centre as shown in Figure 6A, the spark plug 618 is timed to ignite the air fuel mix in the chamber 611, which continues the cycle pushing the pistons 605 and 6 outwardly towards the position shown in Figure 6. Linear outward motion in the piston rods 612 and 613 induces the cam followers 629, 630, 631 and 632 to follow the continuous curved cam track 634 towards the longest chord, translating linear motion in the piston rods 612 and 613 into rotational motion of the continuous cam track 634 about the axis provided by an expansion of the fluids in chamber 611. As the pistons 605 and 606 pass BDC, the exhaust port 616 is opened by rotation of the annular valve 617, and on an upward stroke, exhaust gases flow therethrough into an exhaust (not shown). As the pistons 605 and 606 pass TDC, the annular valve 617 closes the exhaust ports 616 and opens inlet ports 615 allowing air and fuel mix to flow through the inlet ports 15 and 16 into expanding chamber 611. This cycle may be any four-stroke petrol or diesel, 720 degree cycle.

Fig. 7A shows an internal combustion engine 700 generally similar to the internal combustion engine 1, showing a means for taking power from the rotating cam track 734. The cam track 734 is fixed to an annular plate 738 which has an outer rim 737. The cam track 734, annular plate 738 and rim 737 rotate about bearing 740-743 which run along an inner surface of the rim 737. A belt 770 is runs about an outer surface of the rim 737 driving a power -27-take off rotor 771.

Figure 7B shows an internal combustion engine 800 generally similar to the internal combustion engine 1, showing a means for taking power from the rotating cam track 834. The cam track 834 is fixed to an annular plate 838 which has an outer rim 837. The cam track 834, annular plate 838 and rim 837 rotate about bearing 840-843 which run along an inner surface of the rim 837. Spokes 873 are provided forming a hemi-spherical dome end with a gear wheel 847 splined on to a drive rotor 836 fixed to a central point at which ends of the spokes 873 meet. A further gear (not shown) can be used to take power therefrom.

Figure 7C shows an internal combustion engine 900 generally similar to the internal combustion engine 1, showing a means for taking power from the rotating cam track 934. The cam track 934 is fixed to an annular plate 938 which has an outer toothed rim 937. The cam track 934, annular plate 938 and rim 937 rotate about bearing 940-943 which run along an inner surface of the rim 937. The outer surface of the rim 937 is provided with teeth (not shown).

The teeth on the outer surface of the rim 937 mesh with teeth of further gear 978 to take power from therefrom. It is envisaged that the inner surface of the rim 937 is provided with teeth and the further gear wheel is arranged inside of the rim 937 and meshes with the internal teeth of the rim 937.

Figure 7D shows an internal combustion engine 1000 generally similar to the internal combustion engine 1, showing a means for taking power from the rotating cam track 1034. The cam track 1034 is fixed to an annular plate 1038 which has an outer drum 1037. The cam track 1034, annular plate 1038 and drum 1037 rotate about bearing 1040- -28- 1043 which run along an inner surface of the drum 1037. Armature windings 1081 are arranged on the drum and field windings (not shown) are provided on a stator 1080. Relative rotation of the drum 1037 and the stator 1080 induce flow of electricity through the windings, converting kinetic energy provide by the rotational movement of the drum 1037 to electrical energy flowing through the windings 1081. Thus an internal combustion engine of the present invention may be used to generate electricity.

Figure 8 shows an internal combustion engine 1100 generally similar to the internal combustion engine 1, showing a means for taking power from the rotating cam track. The cam track is fixed to an annular plate which has an outer drum 1137. The cam track, annular plate and drum 1137 rotate about bearing which run along an inner surface of the drum 1137. A ball bearing track 1190 is provided about the drum 1137. Ball bearings 1191 are allowed to run freely within the ball bearing track 1190 to facilitate balance of the internal combustion engine of the present invention.

It is envisaged that the cam surfaces 35 may comprise nylon or PTFE (Poly Tetra Flouro-Ethelene or other plastics material or a hard wearing metal material. -29-

Claims

CLAIMS1. An internal combustion engine comprising a cylinder and at least one reciprocating piston (5) therein, a chamber (11) for receiving a fuel and gas mixture, the piston comprising a piston head (7) and a piston rod (12) extending from the piston head, characterised in that the internal combustion engine further comprises a continuous cam track (34) rotatable about an axis, said piston rod (12) comprising a cam follower (29,30), the continuous cam surface rotationally connected to a rotor (36).
2. An internal combustion engine as claimed in Claim 1, wherein the piston rod is rigidly fixed to the piston head.
3. An internal combustion engine as claimed in Claim 1 or 2, wherein the continuous cam track is a continuous loop about said axis.
4. An internal combustion engine as claimed in Claim 3, wherein the continuous cam track is a continuous loop about 720 degrees in the form of a figure of eight.
5. An internal combustion engine as claimed in Claim 3, wherein the continuous cam track is a continuous loop about 360 degrees in the form of a figure of eight.
6. An internal combustion engine as claimed in any preceding claim, wherein the continuous cam track comprises an inner cam surface (33) upon which said at least a part of said cam follower is arranged.
7. An internal combustion engine as claimed in any preceding claim, wherein the continuous cam track comprises an outer cam surface (35) upon which said at least a part of said cam follower is arranged.
8. An internal combustion engine as claimed in any preceding claim, wherein the at least a part of the cam follower comprises a bearing wheel. -30-
9. An internal combustion engine as claimed in any preceding claim, wherein the continuous cam track comprises a continuous curve.
10. An internal combustion engine as claimed in any 5 preceding claim, wherein the continuous cam track comprises at least one portion with sharp changes of direction and shallow changes of direction.
11. An internal combustion engine as claimed in any preceding claim, wherein the continuous cam track is one of: an oval; flattened circle; rectangle having curved corners; a trapezium having curved corners; a parallelogram having curved corners; and an ellipse.
12. An internal combustion engine as claimed in any preceding claim, further comprising an opposing piston (6) in said bore (4) of said cylinder (2), defining a chamber (11) between said piston (5) and opposing piston (6).
13. An internal combustion engine as claimed in Claim 12, wherein the opposing piston (6) comprises an opposing piston head (8) and an opposing piston rod (13) with an opposing cam follower (31,32).
14. An internal combustion engine as claimed in any preceding claim, further comprising a guide apparatus (100,200,300,400) to facilitate guiding the piston rod (12) as it reciprocates and maintains its concentricity with the cylinder (2).
15. An internal combustion engine as claimed in any preceding claim, wherein the guide apparatus comprises a plurality of bearing wheels.
16. An internal combustion engine as claimed in Claim 15, 30 wherein each bearing wheel has a first portion which defines a perimeter of a circle which has a radius and a second portion which is less than the radius. -31-
17. An internal combustion engine as claimed in Claim 15 or 16, wherein the bearing wheel is also provided with a timing mechanism to ensure the major portion of the bearing wheel is in contact with the piston or piston rod during not in contact during a a first portion of its cycle and second portion of its cycle.
18. An internal combustion engine as claimed in Claim 17, wherein the second portion of the cycle includes change in direction of said piston head along said cylinder.
19. An internal combustion engine as claimed in Claim 17, wherein, the timing mechanism comprises a gear wheel arranged on a toothed track.
20. An internal combustion engine as claimed in Claim 19, wherein the track is linear and arranged along at least a portion of the piston rod.
21. 18. An internal combustion engine as claimed in any of Claims 17 to 20, wherein the guide apparatus comprises at least a first cam wheel continuously rotating clockwise and a second cam wheel rotating anticlockwise.
22. An internal combustion engine as claimed in any of Claims 15 to 21, wherein, the guide apparatus comprises at least two cam wheels in any plane about the piston or piston rod.
23. A method for taking longitudinal motion produced by a reciprocating piston of an internal combustion engine into rotational motion in a rotor, wherein the internal combustion engine comprises a cylinder and at least one reciprocating piston (5) therein, a chamber (11) for receiving a fuel and gas mixture, the piston comprising a piston head (7) and a piston rod (12) extending from the piston head, the method comprising the steps of guiding the piston rod with a guide apparatus, the internal -32-combustion engine further comprising a continuous cam track (34) rotatable about an axis (45), said piston rod (12) comprising a cam follower (29,30) , the continuous cam surface rotationally connected to a rotor (36).