PISTON AND CYLINDER DEVICES

Abstract: The invention relates to piston-and-cylinder devices having an output member adapted to drive vehicles, generators or other mechanical arrangements. The device may in its simplest form comprise a cylinder (2) including a chamber (14) at least one piston (16) having an exterior cylindrical surface (18), and which is adapted to partake of a motion having a component of movement lengthwise of the cylinder (2) and a rotatable output member (8). There are also provided cam means comprising a first cam part and a second cam part, one of said cam parts being a cam track arrangement (20) formed for example in the piston surface and the other being a cam follower means (26) formed on the inside surface of the cylinder (2) and adapted to engage said track arrangement (20), the construction and operation being such that said cam means (20, 26) operates to impart to the motion of the piston (16) a rotational component of movement and such that rotary motion produced in the output member (8) is derived from said rotary component of movement of the piston motion. Conveniently, a skirt flange (190) may be provided on the piston to act as a sleeve valve.

Description: .-i - PISTON AND CYLINDER DEVICES The invention relates to piston-and-cylinder devices, particularly but not exclusively to devices having an output member adapted to provide drive or propulsion to vehicles, generators or other mechanical arrangements. The invention provides a piston-and-cylinder device comprising a cylinder, said cylinder including a chamber at least partially defined by an interior surface of said cylinder, at least one piston having an exterior cylindrical surface, said piston being adapted to partake of a motion having a component of movement lengthwise of the cylinder and an output member adapted to rotate about a lengthwise extending axis thereof, wherein there are provided cam means comprising a first cam part and a second cam part, one of said cam parts being a cam track arrangement formed in one of said surfaces and the other of said cam parts being a cam follower means formed on the other one of said surfaces and adapted to engage said track arrangement, the construction and operation being such that said cam means operates to impart to the motion of the piston a rotational component of movement and such that rotary motion produced in the output member is derived from said rotary component of movement of the piston motion. Advantageously, the motion of the piston may be initiated and maintained by a source of chemical or electrical energy. Preferably, the cam track arrangement may be a sinusoidal cam track formed in the exterior surface of the piston and the cam follower means may comprise at least one cam follower projecting from the interior surface of the cylinder chamber. Conveniently, there may be provided two lobes in the sinusoidal path of the cam-track. However, in many applications of the devices according to the present invention, three or more lobes may be found satisfactory or even preferable. Conveniently, the source of energy may be a liquid fuel of various kinds, petrol, alcohol and other high- or low-octane fuels or may be electric or any other suitable source. In some instances of use turbine or other propeller-type blades may be powered which in turn permit by-pass air to be used possibly in the manner of an aircraft-type engine, with additional fuel injection to provide an arrangement similar to that of an after-burner. In some of the examples to be described below, two or more pistons may be arranged in tandem within a single cylinder chamber, said chamber being divided by the pistons into a plurality of sub-chambers. Advantageously, each sub-chamber may be provided with a spark plug or other suitable ignition device for a fuel/air mixture delivered to the sub-chambers so as to operate in a pre-determined two- or four- stroke cycle. According to the lay-out of the device, the output member may be arranged to pass axially through the piston in a manner ensuring the rotation of the output member with the rotary component of movement of the piston motion but compensating for or preventing axial movement with the lengthwise component thereof. The invention also provides in another of its several features a piston-and-cylinder device as described in the second paragraph of the present specification wherein said piston or pistons are provided with a circular or annular end surface adapted to receive an impulse intended to move the piston in the cylinder chamber, said end surface being provided with radially extending fluted portions comprising an array of surface portions arranged obliquely with respect to a radial plane of the piston. Further features and advantages of devices according to the invention will become apparent from the following detailed description of a plurality of embodiments of the invention. It will be understood that the description, which is to be read with reference to the drawings, is given by way of example only and not by way of limitation. In the drawings:- Figure 1 is a schematic, view in longitudinal section of a first device according to the invention including one piston; Figure 2 is a similar view to that of Figure 1 showing the piston of the first device at a different stage in a two-stroke cycle of operation; Figure 3 shows a modification of the first device; Figures 4 & 5 are schematic views in longitudinal section of a second device comprising two pistons in different stages of operation of the device; Figures 6 & 7 are views, similar to Figures 3 and 4, of a third device comprising three pistons; Figures 8 & 9 are views of a fourth device incorporating a lubricant-circulating arrangement; Figure 10 is a cross-sectional view on line X-X of Figure 9; Figure 11 is a fragmentary view of a vaned shaft of the fourth device; Figure 12 is a perspective view of a piston showing an array of fluted portions on an end surface thereof; Figures 13 & 14 are schematic representations of a water and an air-cooled jacket arrangement respectively; Figures 15 & 16 shows the layouts of two exhaust manifold arrangements suitable for use with devices according to the invention; Figures 17 & 18 show lengthwise and transverse views respectively, through auxiliary equipment; Figures 19 & 20 show alternative forms of valve arrangements; Figure 21 shows a perspective view of a modified piston arrangement; Figures 22 & 23 are views similar to those of Figures 8 and 9 showing a further device incorporating the modified piston arrangement in Figure 21; and Figure 24 illustrates a power boost device capable of augmenting the overall engine output. The first device, illustrated in Figures 1 and 2 of the drawings, comprises a hollow cylinder 2 one end wall 4 of which is provided with an aperture having bearings 6 through which projects an output shaft 8 sliding received in an axial slot 10 of a flywheel 12. Relative rotary movement between the shaft 8 and the flywheel 12 is prevented by keying splines (not shown) . Received within a chamber 14 of the cylinder 2 is a piston 16 to which an inner end portion of the shaft 8 is connected. The piston has an exterior cylindrical surface 18 in which is formed a cam track 20 providing a sinusoidal path and having two lobes. A compression sealing ring 22 is provided in an annular groove around the piston 16 in the region of an opposite end face to that connected to the shaft 8, the ring acting also as a scraper device against a portion of an interior surface 24 of the cylinder from which project two cam followers 26. The cam followers 26 may be in the form of studs or bosses, or cylindrical roller members as shown. Such rollers will require a substantially rectangular cross-section cam track but a domed stud or boss may be used with a U-shaped track. As viewed in Figures 1 and 2, there is provided at the left-hand end portion of the chamber 14, a spark plug 28 and an injection nozzle 30 for the provision of a fuel/oil mixture arranged to operate a two-stroke internal combustion cycle. Figure 1 shows the position of the piston 16 as the plug 28 sparks to ignite the fuel delivered by the nozzle 30. As the piston is impelled to the right, the action of the cam followers 26 in the track 20 causes the piston to partake of a motion having not only a lengthwise component of movement but also a rotary component. The extent of lengthwise movement is limited by the throw of the cam track which guides movement between the position of the piston shown in Figure 1 and the position shown in Figure 2. In the Figure 2 position, the piston has moved so as to uncover exhaust ports 32 formed in the cylinder 2. It will thus be appreciated that the piston motion comprises a rotational movement of 180" for each operation of the spark plug 28 and includes a short lengthwise movement. The output shaft 8 thus partakes of a similar short travel motion. However the shaft 8 is splined into the axial slot 10 for sliding movement and therefore only the rotational component of movement is transmitted to the flywheel. It will be found that the operation of the device is appreciably smoother than that of other known operational single-cylinder motors. Although Figures 1 and 2 illustrate a cam track having a two-lobed sinusoidal curve, it will be understood that a single lobe configuration may be used as shown in Figure 3, in which similar parts have been allocated similar reference numerals to those used in Figures 1 and 2. In this modification, only one cam follower 26 is necessary and it will be observed that the lengthwise movement is greater than that required by the arrangement shown in Figures 1 and 2. It will be understood that in many examples advantage may be taken of the ability to use a wide but shallow piston with a cam-track having three or more lobes to provide an exceptionally rapid rate of strokes of the piston. In all cases, suitable water-cooling, or air-cooling jackets or other devices will be required, together with exhaust gas removal passages, but these are omitted in Figures 1-3 for the sake of clarity. In Figures 4 and 5, a second embodiment of the invention is illustrated which is similar to that shown in Figures 1 and 2 in many respects, but differs in that a single spark plug, 34, and a single fuel injection nozzle 36 is positioned at an intermediate region of an elongate cylinder 38 in which are received two cylinders 40,40', each having a two-lobe sinusoidal cam track 42 engaged by two cam-followers 44. Thus the two pistons are arranged to share a common combustion sub-chamber. The piston 40 is provided with a shaft 46 which is received in an axial slot 48 formed in the piston 40'. The shaft 46 is provided with keying members 50 which engage in grooves of the slot 48 to permit lengthwise relative movement but prevent rotational relative movement between the two pistons. It will be observed that at the time when the spark plug 34 operates, the keying members 50 are shielded from possible damage from fuel ignition by being fully received within the slot 48. The piston 40' has an output shaft 52 secured thereto in a manner similar to the mounting of the shaft 6 of Figures 1 and 2, with a similar arrangement of the shaft and a flywheel 54, corresponding to the flywheel 12. Thus, when the spark plug 34 operates to cause ignition of the fuel/air mixture from the nozzle 36, the pistons move apart from each other but as they do so, they rotate simultaneously in the same sense. The rotation of the piston 40 therefore assists the rotation of the piston 40' through the shaft 46 and more power is thus available at the output. Figures 6 and 7 illustrate a third embodiment in which an extended arrangement is shown which avoids any disadvantages which may be encountered under certain circumstances connected with the mounting of the output shaft when the latter is allowed lengthwise movement with respect to the cylinder and the flywheel. In this embodiment, a cylinder 56 provides four combustion regions or sub-chambers, A, B, C and D, of a chamber 58, in which are received three pistons 60, 62, 64, each provided with a sinusoidal cam track 66 engaged by cam followers 68, formed and arranged in a manner similar to that described above. The pistons are, however, provided with axial passages and are mounted for movement lengthwise on a through shaft 70 journalled in gas-tight bearings 72 and 74 at end walls of the cylinder 56, the right hand end of the shaft 70 as viewed in the Figure being connected with a flywheel 76 in a conventional manner. Relative rotational movement between the pistons and the shaft 70 is however prevented by the provision on the shaft 70 of keying members 78 which slide with respect to grooves 80 formed within the axial passage of each piston. The operation of the third embodiment is as follows. With the pistons 60, 62 and 64 in the positions shown in Figure 6, spark plugs 82 in sub-chambers B and D operate to ignite a fuel/air mixture injected from associated ones of nozzles 84. The pistons 60 and 64 therefore move in a leftward direction and piston 62 moves to the right, all three pistons rotating through 90° as they move lengthwise with the cylinder. When they have reached the positions shown in Figure 7, the pistons 60 and 64 are then moved towards the Figure 6 again by the operation of the spark plugs 82 in sub-chambers A and C to ignite a fuel/air mixture injected by the appropriate nozzles 84. The rotational movement of the pistons is thus transferred to the output shaft 70, with the advantage that each stroke of the pistons is a power stroke, thus enabling considerable output to be achieved. Moreover, it has been found that the presence of the shaft in a central position in each combustion sub-chamber has an advantageous effect on the distribution of the fuel as it is injected, due to the deflecting action of the shaft on the injected stream which disperses the fuel more evenly throughout the available space, the ensuing ignition explosion impinging upon the end surface of the piston in a more even manner than is conventional in internal combustion engines. Figures 8, 9 and 10 illustrate a fourth embodiment of the invention which includes a cylinder 86 in which are received two pistons 88 and 90 mounted for movement upon an output shaft 92 journalled in gas-tight bearings 94, 96 in end walls of the cylinder 86. The operation of the pistons 88, 90 and spark plugs 98 and associated injection nozzles 100 is similar to that described above, the pistons moving in a reciprocating motion on the shaft 92, the motion having components of axial and of rotational movement. Outward and inward strokes are powered, since there is provided a plug 98 and fuel inlet 100 in each of the three combustion chambers. The construction of the pistons 88 and 90 will however be described, with reference to a convenient lubrication system, enabling a separate oil supply rather than the addition of oil to the fuel as in a two-stroke cycle. Each piston 88, 90 comprises a main body portion 102 and two end plates 104 in screw-threaded engagement with .-li¬ the body portion. Oil seals 106 are provided in addition to piston rings 108. Further oil seals 110 are provided in annular blocks 112 which form end faces of a hollow chamber E within the piston. Cam-tracks 114 are provided in the blocks 112, and are engaged in a manner similar to that described above by cam followers 116. Projecting inwardly of the chamber E from the block 102 are two pairs of flanges 118; between the flanges of each pair is received one of two vanes 120 projecting from the shaft 92. Shaft 92 is hollow for most of its illustrated length and provides a centrally arranged passage 122 for the supply of oil from an oil feed 124. Orifices 126 allow the oil to pass into the chamber E and thence through restricted orifices 126 to the cam track 114 to lubricate the piston movement. A spiral groove 128 is provided in the interior wall of the cylinder 86 to carry away the oil from the cam track 114 and the exterior surface portion of the piston between the seals, in order to allow its return to an external sump by means of a vacuum pump (not shown) , for re-use at oil feed 124. On each outer face of the end plates 104 there is provided an array of radially extending fluted portions 130 (Figure 12) arranged at an oblique angle to a radial plane of the cylinder 86, with intervening surface 132 each lying in an axial plane. The advantage of such a layout is that the ignition explosion impinges on the surfaces 130 at an angle and this acts to enhance the desire rotational motion. With respect to the cooling of the devices illustrated, the cylinders may be received within a water cooled jacket 134 as shown in Figure 13 or an air-cooled jacket 136 as shown in Figure 14. In arrangements including air-cooled outer jackets, it is envisaged that a fan or turbine blade arrangement 138 may be provided to drive air through the annular space between the jacket and the cylinder in the direction indicated by arrows F. A second fan 140 may also be provided to assist in pulling air through the space. The space between the jacket and the cylinder may also be used, with suitable ducting, to accommodate and remove exhaust gases from exhaust ports 32, 32'shown in the various Figures. In the examples these ports have been usually illustrated for the sake of simplicity as ports without valves, the ports being covered and uncovered as the pistons move. Figures 15 and 16 show cross-sectional views of exhaust arrangements including three-port and two-port lay-outs respectively, according to the required gas-flow characteristics. The Figures illustrate a cylinder 142 having a shaft 144 passing through its piston(s) with ports 146 leading to exhaust manifold arrangements 148 via annular space 150 between the cylinder 142 and a jacket 152. Fuel/air inlet positions are also indicated at 154. Figure 17 shows a side elevation of an arrangement ri3- illustrating a lay-out using the example shown in Figure 8 and 9, but provided with the required auxiliary equipment. For the sake of simplicity the details of the piston-and-cylinder device is indicated by the area F. Although an air-cooled arrangement may be found satisfactory. Figure 17 shows a water pump 156 taking coolant from a water jacket 158 to a radiator G (not shown) . An exhaust impeller 160 driver from the device F, takes exhaust gas from an exhaust manifold 162 to exhaust and an induction impeller 164 pressurises the fuel/air mixture in an induction manifold 166. An alternator and control gear arrangement 168 is mounted on an auxiliary shaft 170. It will be understood that equipment requiring power may be mounted, not directly on its shaft but may operate through gearing or clutch devices as necessary. Because of lay-out problems which would arise particularly with the use of multiple entry and exhaust parts to improve combustion, the use of specialised valve devices will be advantageous. Such a valve device is shown in Figures 18 and 19. Referring to Figure 19, an electromagnet 172 is provided with a central aperture 174 through which passes a stem 176 of a valve 178. The stem 176 is set in sliding bearings 180 (Figure 18) in the manifold body. The outer end of the valve comprises a collar 182, with a compression spring 184 received between the collar and the magnet 172. Energisation of the magnet will attract the collar 182 and compress the spring, which will act as a return spring to force the valve to return to its original position when the magnet is de-energised. Figure 18 shows one valve 178 in an energised state and one in its de-energised state. The energisation of the magnet 172 is controlled by a suitable electronic sequencing device, directing current to the valves in the required sequence, its power being initially derived from a battery (not shown) and thereafter from the alternator 168. Control of the sequencing rate would be also derived from the throttle action on the fuel/air supply (carburettor) . An alternative form of valve is shown in Figure 20, in which a small linear motor 186 surrounds the valve stem 176, which then becomes the armature of the motor. A frequency converter or frequency generator (not shown) will also be provided in the arrangement since the linear motor speed normally depends on the frequency of an alternating current. The frequency converter thus operates upon the sequencer and thence the valves 178. Yet another alternative arrangement is illustrated in Figures 21 to 23 in which end face 188 of the pistons is provided with a cylindrical flange 190 extending axially therefrom in the form of a skirt. The flanges are provided with apertures 192 which are arranged to co-incide with apertures in the wall of the cylinder (for example, cylinder 86 in Figure 10) at a stage in the cycle. Since there is a fuel/air mixture present in the cylinder openings under conditions of increased pressure and the exhaust system is under reduced pressure (evacuation) the skirt-like flange 190 will be seen to operate in the manner of a sleeve valve with no moving parts other than the piston itself. This is illustrated in Figures 22 and 23 in which parts shown which are similar to those illustrated in Figures 8 and 9 are given similar reference numerals provided with a suffix, for example spark plugs 98'. The sequence of operations is similar to that described in relation to Figures 8 and 9. However, in Figures 22 and 23, the pistons 88', 90' are provided with the above mentioned skirt-like flanges 190. Although the aperture 192 will vary in shape and position according to the layout of the piston-and-cylinder arrangement, the present layout includes operations which when for example the middle spark plug operates, (Figure 22) are positioned to allow the spark to ignite the fuel/air mixture and, as shown in Figure 23, then to allow passage for the exhaust gases through ports 32'. It will be observed that the ports 32' are valveless since the flanges 190 act as sleeves in a sleeve valve. Thus the only moving parts in the arrangement ar the shaft and pistons. A further embodiment of the invention is suitably employed in an arrangement capable of providing a short-term impulse or boost to the piston engine, in a similar manner to that in which a jet engine is provided with "after-burn" capabilities. Figure 24 shows an example of such a boost arrangement in the context of the present disclosure. An engine 194 constructed as before described is arranged to drive a compressor/fan arrangement 196,198, one at each of the front and rear ends of the engine body. The fans drive a large quantity of air through an annular space 200 between the engine cylinder and the outer jacket 202. The engine is cooled by this air flow which air is compressed by the fans and the contouring of the jacket housing rearwardly of the second fan 198 around a contoured flow control body 204. The compressed air now enters an annular combustion chamber 206 to which is supplied fuel (without air admixture) in the form of fine droplets from an array of spray jets 208. The hot gasses from ignition at this stage pass through a turbine 210 which is linked to the engine 194 and so assists its power output. The exhaust gases also contribute a measure of thrust so enhancing the overall power output. The arrangement will also be provided conventionally with stator blades 212 as well as turbine blades. The stator blades are mounted in association with a further contoured body portion 214, which is appropriate may be movable axially of the exhaust outlet 216 to assist in the control of exhaust gas pressure and velocity. Various modifications may be made within the scope of the invention as defined in the following claims.

Claims: CLAIMS : 1. A piston and cylinder device comprising a cylinder, said cylinder including a chamber at least partially defined by an interior surface of said cylinder, at least one piston having an exterior cylindrical surface, said piston being adapted to partake of a motion having a component of movement lengthwise of the cylinder and an output member adapted to rotate about a lengthwise extending axis thereof, wherein there are provided cam means comprising a first cam part and a second cam part, one of said cam parts being a cam track arrangement formed in one of said surfaces and the other of said cam parts being a cam follower means formed on the other one of said surfaces and adapted to engage said track arrangement, the construction and operation being such that said cam means operates to impart to the motion of the piston a rotational component of movement and such that rotary motion produced in the output member is derived from said rotary component of movement of the piston motion. 2. A device as claimed in claim 1 wherein the cam track arrangement is a sinusoidal cam track formed in an exterior surface of the piston and the cam follower means comprise at least one cam follower projecting from the interior surface of the chamber. 3. A device as claimed in claim 2, wherein the cam followers are studs or roller devices. 4. A device as claimed in claim 2, wherein the cam track has two lobes. 5. A device as claimed in claim 2, wherein the cam track has three lobes. 6. A device as claimed in any of the previous claims, wherein two or more pistons are arranged in tandem within a single cylinder chamber, said chamber being divided by the pistons into a plurality of sub-chambers. 7. A device as claimed in claim 6, wherein each sub-chamber is provided with an ignition means so as to operate in a predetermined two- or four-stroke cycle. 8. A device as claimed in claim 1, wherein the output member is arranged to pass axially through the piston to ensure rotation of said output member with the rotary component of movement of the piston movement, axial movement of the output member with the lengthwise component of the piston member movement being minimised or prevented. 9. A device as claimed in any one of the preceding claims, wherein the motion of the piston(s) is initiated and maintained by a source of chemical or electrical energy. 10. A device as claimed in claim 9, wherein the source of energy is a liquid fuel. 11. A device as claimed in claim 1, wherein said piston or pistons are provided with a circular or annular end surface adapted to receive an impulse intended to move the piston in the cylinder chamber, said end surface being provided with radially extending fluted portions comprising an array of surface portions arranged obliquely with respect to a radial plane of the piston. 12. A device as claimed in either one or claims 1 and 11, wherein the output member co-operates and drives a flywheel arrangement. 13. A device as claimed in any one of the preceding claims, wherein there are provided two pistons sharing a common combustion chamber. 14. A device as claimed in claim 13, wherein the two pistons are flanked by two further combustion chambers. 15. A device as claimed in any one of claims 6 to 14, wherein the pistons are provided with axially arranged passages through which pass a continuous shaft, said shaft being provided with keying members, and said pistons being provided with grooves to receive said keying members to prevent relative rotational movement between said shaft and said pistons, said shaft passing through each of said combustion chambers. 16. A device as claimed in claim 6, wherein there is provided an external cylindrical sleeve arrangement defining passageways for water-cooling, oil supply and air and exhaust gas flows, inlets and outlets for said flows being spaced axially and/or radially around the circumference of the cylinder. 17. A device as claimed in claim 16, wherein at least the gas flows are controlled by electromagnetic valves operating in tangentially offset flow inlets/outlets. 18. A device as claimed in either one of claims 1 and 6, wherein at least one end face of said pistons is provided with a cylindrical flange extending axially therefrom in the form of a skirt. 19. A device as claimed in claim 18, wherein the skirt is provided with apertures arranged to coincide with flow inlets and outlets in turn at appropriate stages in the operating cycle in the manner of a sleeve valve. 20. A device as claimed in any of the preceding claims, wherein the output member is provided with turbine or similar propeller blades to permit a by-pass air flow, additional fuel injection means being provided to achieve an after-burner arrangement.

Inventors: FISHER HUGH EDWARD, FISHER, HUGH, EDWARD
Applicants: FISHER HUGH EDWARD, FISHER, HUGH, EDWARD
Application year: 1993
Main classification: F01B3
IPC codes: F01B3