NZ337971A

NZ337971A - Combustion engine with cylinders and back to back piston pair axes arranged about shaft axis, with axial adjustment of pistons

Info

Publication number: NZ337971A
Application number: NZ337971A
Authority: NZ
Inventors: Leif Dag Henriksen
Original assignee: Sinus Holding Anonyme Soc
Priority date: 1997-04-25
Filing date: 1998-04-22
Publication date: 2001-06-29
Also published as: NO306422B1; NO971906D0; BR9808980A; DK0977938T3; TW388785B; AU7351898A; HUP0000736A2; EP0977938B1; CN1097149C; CZ291216B6; DE69806147T2; NO971906L; CA2287378A1; AU726948B2; EP0977938A1; HUP0000736A3; PL336380A1; ES2178835T3; DE69806147D1; WO1998049436A1

Abstract

A combustion engine (10) comprises a number of engine cylinders (21), which are arranged in an annular series around a common middle drive shaft (11). Each cylinder includes a pair of pistons (44, 45) movable towards and away from each other and a common, intermediate working chamber (K') for each pair of pistons. Each piston (44, 45) is equipped with its piston rod (48, 49) with associated support roller (53) which forms a support against its respective "sine" - curve shaped cam guide device (12a, 12b), which controls movements of the piston relative to the associated cylinder. A least the one (44) of the two pistons (44, 45) in each cylinder (21) is regulatably adjustable axially in the cylinder especially for regulating the compression ratio in the common working chamber (K')

Description

<div class="application article clearfix" id="description"> WO 98/49436 PCT/N098/00126 1 ARRANGEMENT IN A COMBUSTION ENGINE WITH INTERNAL COMBUSTION The present invention relates to an arrangement in a combustion engine having internal combustion, comprising a plurality of engine cylinders, which are arranged in an annular series around a common central drive shaft and 5 which have cylinder axes running parallel to the drive shaft, each cylinder including a pair of pistons movable towards and away from each other and for each pair of pistons a common, intermediate work chamber, while each piston is equipped with its axially movable piston rod, 10 the free outer end of which forms via a support roller a support against its curve-shaped, that is to say 'sme'-curve shaped, cam guide device, which is arranged at each of opposite ends of the cylinder and which guides movements of the piston relative to the associated 15 cylinder. In US 4 432 310 and 5 215 045 there is shown an engine arrangement with a number of pistons which are arranged individually each in its separate cylinder. The cylinders are arranged in pairs in axially mutually 20 parallel rows and are equipped with pistons synchronously movable in pairs, that is to say the pistons are physically connected to each other m their respective pair of cylinders. There is employed in this connection a middle cam guide device, which is common to each and all 25 of the cylinders of the engine and which jointly controls each pair of mutually connected pistons. In other words Printed from Mimosa 09/23/1999 11:37:41 page -3- WO 98/49436 PCT/NO98/00I26 2 each cylinder has its respective separate cylinder volume with its respective separate piston, but with a common control of each and all pistons in respective strokes. From for instance US 5 031 581 (1989) a solution is 5 known correspondingly as indicated by way of introduction. More specifically a four stroke combustion engine is known having two separate cam guide devices. Each cam guide device cooperates with its respective set of pistons and with its respective associated set of support rollers. The 10 cylinders are arranged in an annular series around the drive shaft. The pistons, which are received in pairs in a respective one of the cylinders, are served by two separate cam guide devices, that is to say the one piston of each pair of pistons is controlled by a first cam guide 15 device, while the remaining piston is controlled by a second cam guide device. Each cylinder is consequently equipped with pairs of separate pistons movable towards and away from each other each with its separate piston rod, which cooperates individually via an associated 20 support roller with a respective one of two opposite sets of "sine' - planes, which form a part of their respective cam guide device and which control the pistons according to a "sine" - concept known per se>. The cam guide devices of the two axially distinct groups of pistons are arranged 25 axially endwise outside respective end of the engines. The piston heads of said pairs of pistons face mutually towards each other in a common working chamber of the associated cylinder, that is to say towards a common working chamber, which is arranged midway between said 30 pair of pistons. In GB 2 019 487 a four cylinder two stroke engine is shown with a pair of pistons going towards and away from each other in each of said four cylinders. An arrangement is employed where the ignition occurs simultaneously in 35 two of the four cylinders, that is to say in pairs of alternate cylinders. In the patent specification it is indicated that the contour of the cam can be designed so Printed from Mimosa 09/23/1999 11:37:41 page -4- WO 98/49436 PCT/N098/00126 3 that the pistons can be moved in a most favourable manner in connection with expansion of the combustion product. There is employed a desired level or steady contour for emptying or scavenging of exhaust before new fuel is 5 introduced into the cylinder. In the drawings there is shown, m each of two mutually opposite cam grooves, a more or less rectilinear, local cam contour in mutual turning points lying directly opposite each other forming "sine" - curve portions. More specifically the rectilinear 10 cam contour is illustrated in only the one of two succeeding, turning points of the "sine"-curve forming "sine"-curve portions, namely where the respective pistons occupy one after the other their most remote outer positions with exhaust and scavenging ports open to the 15 maximum. The present invention, which primarily relates to two cycle engines, but which can also be applied to four stroke engines, takes its starting point as to arrangement m the piston and cylinder arrangement according to the 20 afore-mentioned US 5 031 581. With the present invention the aim is to be able to regulate the compression ratio in cylinders of the engine m a simple and ready, but at the same time controlled, precise and reliable manner, that is to say the aim is to 25 regulate the compression ratio in the common working chamber which is defined between two piston heads of the cylinder facing towards each other. The arrangement according to the invention is characterised m that at least the one of the two pistons 30 in each cylinder is regulatably adjustable in the cylinder for regulating the relative spacing between the pistons, especially for regulating the compression ratio in the common working chamber between the pistons. According to the invention one is consequently in a 35 position to regulate the compression ratio m the working chamber between two pistons of the cylinder by quite Printed from Mimosa 09/23/1999 11:37:41 page -5- -7/ ^ * /f ^ V, , 3a An aim is to be able to regulate the compression ratio m cylinders of the engine m 5 a similar way as suggested in FR-A-2 732 722, but with additional advantages. It is of especial interest to provide an engine construction operating in a controlled, precise and reliable manner based on a constructional simple and reliable drive shaft structure. 10 A further aim is to employ a "sine"-like curve shaped, cam guide device instead of the disc shaped cam guide device suggested in FR-A-2 732 722. By the use of a "sine"-like curve shaped, cam guide device it is made possible to guide the associated pistons in a more 15 advantageous manner to improve the total engine effect. More detailed uhe "sine"-like curve shaped, cam guide device enables incorporation of different local variations m each engine stroke m order to improve the total engine effect. It is, however, of utmost importance that the cam guide devices 2 0 and their connection with the drive shaft have a favourable design and are sufficiently reliable in operation. A preferred arrangement of the invention is characterised m that at least one of the cam guide devices is axially movable m relation to a one-piece drive shaft and 25 is provided with a hydraulic mechanism, for separately adjusting the position of said at least one guide device, including regulation of the relative spacing between the pistons, said hydraulic mechanism includes an annular pressure oil chamber and a simulator piston, said simulator 3 0 piston is partitioning said chamber into two sub-chambers, and each chamber is connected to a respective one of two pressure oil circuits. SUBSTITUTE SHEET AWiENDED SHEET "intellectual propertyI office of n z. i 2 3 feb 2001 ' i deceived i 3b 3y regulating the position solely for the one cam guide device the regulation arrangement is rendered especially simple and other significant advantages can be obtained m the general function of the engine, as will be described further below. Alternatively, to regulating the position for only the one cam guide device, it is possible to regulate the position for each of the cam guide devices synchronously or individually, all according to the requirements for additional adjustment between the movements of the pistons in each piston pair. One is in a position to regulate the compression ratio in the working chamber between two pistons of the or each cylinder of the engine m a rather simple and reliable manner by means of said hydraulic mechanism. SUBSTITUTE SHEET AMENDED SHEET intellectual property office of n z 2 3 feb 2001 ' received WO 98/49436 PCT/N098/00126 simply regulating the position of only the one piston in its associated cylinder. With the present invention a particular aim furthermore is to be able to regulate the compression 5 ratio of the cylinders of the engine as a whole and to effect the regulation with one and the same control means. The arrangement according to the invention is in this connection characterised in that the position of the piston m the cylinder is adapted to be fixed via the 10 associated cam guide device of the piston by means of a separately regulatable arrangement. By the fact that the cam guide device is common to the one piston of each and all the cylinders there can be achieved effectively and in an accurately controllable 15 manner corresponding regulation of the position for said one piston of each of the cylinders relative to its associated cylinder by means of one and the same cam guide device. In practice the afore-mentioned regulation is 20 effected by the said one cam guide device being axially displaceable along the drive shaft in a sliding abutment on this, and is adjustable within a limited length of the drive shaft, by means of said separately regulatable control arrangement. 25 Consequently by adjusting the cam guide arrangement for the one piston in each cylinder axially along the drive shaft the compression ratio adjusts at the same time m each cylinder with a regulation via one and the same common control arrangement. 30 More specifically one has according to the invention made it possible to regulate the compression ratio for the cylinders of the engine as a whole, by means of for instance only the one cam guide device, each of the cam guide devices being common to all cylinders of the engine. 35 Alternatively to regulating the position for only the one cam guide device, it is possible to regulate the Printed from Mimosa 09/23/1999 11:37:41 page -6- It is made possible to regulate the working volume between pistons of the cylinders as may be required, that is to say during use, and particularly during cold start of the engine and back to normal operation after the engine is run sufficiently warm. A favourable constructional solution of the present invention is that a one-piece drive shaft is being used and that each cam guide device is rotative with the drive shaft and that at least one cam guide device is axially movable along the drive shaft. This means that the cam guide devices and the drive shaft can be realised m rather compact and dimentionally restricted construction. A further favourable constructional solution of the present invention is that the pressure oil chamber is defined m an annular spacing between the drive shaft and the cam guide device, and that said piston is projecting from its cam guide device radially inwardly in said chamber. It is also advantageous that the piston is passed through parallel to the axis of the drive shaft by a set of driving bolts, which allow a certain axial movement of the piston relative to the drive shaft, while the driving bolts are connected at their respective opposite ends to the drive shaft and connected to a carrying member fastened to the drive shaft. SUBSTITUTE SHEET AMENDED SHEET i intellectual property i office of nz i 2 3 feb 2001 . r e c eiv £ j) ? 'J / £ 7 ft V> / j , " i' It is especially interesting 5 to change the compression ratio m connection with the starting up of the engine, that is to say on cold start. It is furthermore interesting in addition to be able to change the compression ratio during operation in order thereby to obtain a most favourable compression ratio possible during 10 normal operation. Consequently it can be of interest to change the compression ratio during operation of the engine for various reasons. It is preferred that the one piston of the cylinder, which is designed to regulate the 15 position of in the associated cylinder, constitutes a piston which controls opening and closing of exhaust ports of the cylinder. In practice said one piston of each cylinder controls opening and closing of one or more exhaust port(s) of the 20 cylinder and the other piston of each cylinder controls opening and closing of one or more scavenging port(s) . Accordingly, at the same time as the compression ratio is regulated between the pistons, there is in addition achieved the possibility to regulate the opening and closing 25 sequence of the associated exhaust ports. Inter alia the flow-through passages of the exhaust ports can hereby be defined as required. Further the moment of opening and closing of the exhaust ports can be displaced m relation to normal ODeration. SUBSTITUTE SHEIT intellectual property office of n.z. «.:;.vded s*cf 2 3 feb 2001 Received WO 98/49436 PCT/N098/00126 7 greatest need for this and at the same time the exhaust ports are controlled in a favourable manner relative to the subsequent compression stroke, so that a high operative temperature is also obtained at a timely stage 5 during the operation. According to the invention the temperature m cylinders of the engine can be obtained by means of residual exhaust gases being held at a higher temperature level than otherwise possible. In other words there is obtained at the start of the engine a certain 10 checking of the emptying of the exhaust , that is to say less complete emptying of the hot exhaust gases from the working chamber of the cylinder. This means in turn that the working chamber is kept at a relatively high temperature in the starting up phase, at the same as one 15 gets in the following compression stroke the intended high compression and correspondingly rapidly obtains a high combustion temperature. Both effects are favourable on starting up the operation of the engine in cold conditions. 20 By means of thermosensors it can be automatically ensured if desired that the cam control be readjusted from a position having high compression to a position having equivalently lower compression, gradually as the engine is warmed up. If necessary extra regulating equipment can be 2 5 employed for manual adjustment of the compression level as required. The afore-mentioned situation is especially favourable in connection with the remaining regulation of the working conditions individually for the two pistons m 3 0 each cylinder. In this connection it is preferred that the respective cam guide devices of the two pistons, at least in certain portions of the "sine" - plane, are phase-displaced relative to each other. Inter alia one can hereby achieve according to the 35 invention a favourable separate control of the exhaust ports via the one group of pistons and separate, favourable control of the scavenging air ports via the Printed from Mimosa 09/23/1999 11:37:41 page -9- 8 other group of pistons via their respective separate cam guide devices. Further preferred features of the present invention will be evident from the following description having regard to the accompanying drawings, which show some practical embodiments and in which: Fig. 1 shows a vertical section of an engine according to the invention. Fig. la and lb show in a corresponding segment of Fig. 1 vital parts of the engine and illustrate in Fig. la pistons of the engine in a position with maximum mutual spacing and m Fig. lb pistons of the engine in a position with minimal mutual spacing. SUBSTITUTE SHEET RECEIVED 57; 9_ ^ Fig. 2 shows schematically a first cross-section illustrated at one end of the cylinder of the engine in which tnere is shown a scavenging air intake. Fig. 3 shows schematically a second cross-section 5 illustrated at the other end of the cylinder of the engine, m which there is shown an exhaust outlet. Fig. 4a shows schematically m a third cross-section, the middle portion of the engine cylinder, where the fuel is supplied and the ignition of the fuel occurs, 10 illustrated m a first embodiment. Fig. 4b shows m a cross-section, which corresponds to Fig. 4a, the middle portion of the cylinder according to a second embodiment. Fig. 5a shows in longitudinal section a segment of IS the engine according to Fig. lb. Fig. 5b shows a cam guide device witn associated drive shaft, illustrated in longitudinal section with a segment of tne engine according to Fig. lb. Fig. 5c shows a cross head m side view. 2 0 Fig. 5d ana 5e show the cross head according to Fig. 5c seen respectively from above and below. Fig. 5f shows the piston rod seen in side view. Fig. 5g shows the piston rod according to Fig. 5f seen from above. 25 Fig. 5h shows a piston m vertical section. Fig. 6-8 show schematically illustrated and spread m the plane of the drawing a general pattern of movement for a first of two pistons associated with each cylinder, SO used m connection with a three cylinder engine, and illustrated m different angular positions relative to the rotary movement of the drive shaft. Fig. £a shows scnematically the principle for transferring motive forces between the roller of the piston rod 3 5 and an associated ooliquely extending portion of a "sine" - Diane. AMENDED SHEET c r # 10 Fig. 9 shows schematically illustrated and spread in the plane of the drawing a more detailed pattern of movement for two pistons of each cylinder, illustrated in different angular positions relative to the rotary movement of the drive shaft, illustrated m connection with a five cylinder engine. Fig. 10 shows m a representation corresponding to Fig. 9, the pistons m respective positions relative to associated cylinders, m a subsequent working position. Fig. 11 snows schematically a segment of a central portion of a "sine" - plan for two associated pistons of each cylinder. Fig. 12 shows a detailed curve contour for a "sine" -plane for a first piston m each cylinder. Fig. 13 shows a corresponding detailed curve contour for a "sine" - plan for a second piston m each cylinder. Fig. 14 shows a comparative compilation of the curve contours according to Fig. 12 ana 13. Fig. 15 snows m section and m longitudinal section an alternative construction of a cam guide device with associated pressure rollers arranged at the outer end of a piston rod. Fig. 15 shows the same alternative solution, as illustrated in Fig. 15, shown m section m a direction radially outwards from the cam guide device. Fig. 17 ana IS show m elevation and m horizontal section respectively the guiding of the head portion of the piston rod along a pair of control bars extending mutually m parallel. In connection with Fig. 1 a two cycle combustion engine 10 having internal combustion shall generally be referred to herein. Especially there shall be described such a motor 10 adapted according to a so-called "sine" -concept. In Fig. 1 tnere is illustrated in particular a combustion engine 10 shown in cross-section and in a schematic manner. AMENDED SHEET 2 3 feb 2001 RECEIVED In Fig. 1 there is shown a combustion engine 10 having internal combustion illustrated in cross-section and m a schematic manner. As an embodiment there is shown a two cycle combustion engine 10, but as mentioned the solution can also be applied to a four cycle engine, without the specific embodiment of this being described herein. There is specifically proposed a solution for changing the compression ratio of the engine during use. The change of the compression ratio will however also be able to have an influence on remaining operating conditions of the engine as will be evident form the following description. The following description refers to different aspects according to the invention which have direct or indirect significance for various functions of the engine and effects following from this. A preferred objective is inter alia a favourable control of the opening and closing of exhaust oorts 25 ana scavenging ports 24 as will be described further oelow. Furtnermore the aim is combustion m a specially defined combustion chamber K1, as will be described in more detail below. In the illustrated embodiment a drive shaft is constructionally snown m the form of a drive stump shaft, which passes axially and centrally through the engine 10. The drive snaft 11 is provided with a first head portion I2a projecting radially outwards, which constitutes a first cam guide device. The drive snaft is further provided with a second neaa portion 12b projecting equivalentlv outwards, which constitutes a second cam guide device. The neaa portions/ the cam guide devices 12a,12b in the illustrated emoodiment are represented separately and are connected separately to the drive shaft 11 each with their _astemng means. intellectual property office of n 2. AMENDED SHEET 2 3 feb 2001 received 5 10 15 20 25 30 WO 98/49436 PCT/N098/00126 12 The cam guide device 12a surrounds the drive shaft 11 at its one end 11a and forms an end support against end surface lib of the drive shaft 11 via a fastening flange 12a' and is stationarily secured to the drive shaft via fastening screws 12a''. The cam guide device 12b surrounds a thickened portion 11c of the drive shaft 11 at its opposite end portion lid. The cam guide device 12b is not, as is the cam guide device 12a directly secured to the drive shaft 11, but is on the other hand arranged axially displaceable a limited extent axially along the drive shaft 11, especially with the idea of being able to regulate the compression ratio in cylinders 21 of the engine 10 (only the one of a number of cylinders is shown in Fig. 1). End portion lid (see Fig. 1 and 5a) of the drive shaft 11 forms a radially offset sleeve portion to which there is fastened cup-shaped carrying member 13. The carrying member 13 is provided with a fastening flange 13' which with fastening screws 13'' is secured to end portion lid of the drive shaft 11. Between upper end surface 13a of the carrying member 13 and an opposite shoulder surface lie of the drive shaft 11 there is defined a pressure oil chamber 13b. In the pressure oil chamber 13b there is slidably received a compression simulator 12b' in the form of a piston-forming guide flange, which projects from the inner side of the cam guide device radially inwards into the pressure oil chamber 13b for sliding abutment against the outer surface of the end portion lid. In order to prevent mutual turning between the cam guide device 12b and the carrying member 13 and the drive shaft 11 the guide flange 12b' is passed through by a series of guide pins 12' which are anchored in their respective bores in the end surface 13a of the carrying member 13 and in the shoulder surface lie of the drive shaft 11. Printed from Mimosa 09/23/1999 11:37:41 page -14- 5 10 15 20 25 30 WO 98/49436 PCT/N098/00126 13 The pressure oil chamber 13b is supplied pressure oil and is drained of pressure oil via transverse ducts llf and llg through end portion lid of the drive shaft 11. An oil guide means 14, which is put axially inwards into mutually aligned axial bores in the end portion lid of the drive shaft 11 and in fastening flange 13' of the carrying member 13, provides for pressure oil and return oil to be led to and from the ducts llf and llg via separate guide ducts 14a and 14b and adjacent annular grooves 14a' and 14b' in the oil guide means 14. Control of pressure oil and return oil to an from the pressure oil chamber 13b on opposite sides of the compression simulator 12b' of the cam guide device 12b takes place from a remotely disposed commercially conventional control arrangement, not shown further, m a manner not shown further. The drive shaft 11 is, as shown in Fig. 1, connected at opposite ends to equivalent drive shaft sleeves 15a and 15b. The sleeve 15a is fastened with fastening screws 15a' to the cam guide device 12a, while the sleeve 15b is fastened with fastening screws 15b' to the carrying member 13. The sleeves 15a and 15b are rotatably mounted in a respective one of two opposite main support bearings 16a,16b, which are fastened at opposite ends of the engine 10 in a respective end cover 17a and 17b. As shown m Fig. 1, the end covers 17a and 17b are correspondingly fastened to an intermediate engine block 17 by means of fastening screws 17'. Internally in the engine 10 a first lubricating oil chamber 17c is defined between the end cover 17a and the engine block 17 and a second lubricating oil chamber 17d between the end cover 17b and the engine block 17. There is shown an extra cap 17e attached to the end cover 17b and an external oil conduit 17f between the lubricating 011 chamber 17c and the oil cap 17e. Further there is illustrated a suction strainer 17g connected to a lubricating oil conduit 17h which forms a communication Printed from Mimosa 09/23/1999 11:37:41 page -15- e , ~ ^ - r< • e c ^ ^ , r r- e e - * * <1 * • r f f * r, t • *■ t?7 ^ between the lubricating oil chamber 17d and an external lursri eating oil arrangement (not shown further). The oil guide means 14 is provided with a cover-fcrmmg head portion 14c whicn is fastened to end cover 17b of the engine 10 with fastening screws 14c'. The cover-forming head portion 14c forms a sealing off relative to the lubricating oil chamber 17c endwise outside the support rearing 15b. Correspondingly tnere is fastened to the end cover 17a endwise outside the support oearmg 15a a sealing cover 14d with associated sealing ring 14e. The engine 10 is consequently generally constructed of a driven component, that is to say a rotatable component, and a driving component, tnat is to say a non-rotating component. The driven component comprises drive snaft 11 of the engine ana carrying member 13 of the drive snaft and drive snaft sleeves 15a, 15b plus tne cam guide devices 12a and 12b, wmch are connected to the drive snaft 11. The driving, non-rotating component comprises cylinders 21 of the engine with associated pistons 44,45. There is ensured a regulation of tne compression ratio of the engine by effecting a regulaticn internally, tnat is to say mutually between the parts of tne driven component. More specifically tne cne cam guide device 12b is displaced axially cacKwards and forwards relative to the drive shaft 11, that is to say "ithin the defined movement space m said pressure oil cnamoer 13a, which is determined by the guide flange 12b' and the part-chambers of the oil cnamber 13a on opposite sides of the guide flange 12b' . In practice it is a question of a regulation lengtn of some few millimetres for smaller motors and of some centimetres for lar-er engines. The respective volume differences of tne associated working chancers have however equivalent compression effects m the different engir-es ■ I OrF/CE OF NZ | I 2 3 FEB 2001 I AMENDED SHEET D 0 0 . i received i 5 10 15 20 25 30 WO 98/49436 PCT/N098/00126 15 For instance a stepwise or stepless regulation of the compression ratios can be considered according to need, for example adapted with graduated control of the cam guide device 12b to respective positions relative to the drive shaft 11. The control can for example occur automatically by means of electronics known per se. based on different temperature sensing equipment, and the like. Alternatively the control can occur by manual control via suitable regulation means, which are not shown further herein. By effecting the regulation of the cam guide device 12b in connection with the driven component of the engine, one avoids influence on the general control of the arrangement of associated piston 44, piston rod 48, mam support wheel 53 and auxiliary wheel 55, that is to say influence on the mechanical connection between the driving component and the driven component is avoided. On the other hand, with such a regulation of the cam guide device 12b, there is obtained an axial regulation internally in the driving component, m such a way that the arrangement of piston 44, piston rod 48, main support wheel 53 and auxiliary wheel 55 can be displaced collectively via the cam guide device 12b relative to the associated cylinder 21, independently of the concrete compression regulation in practice. In Fig. 1 and lb there is indicated by a broken line a centre space 44' between the piston heads of the pistons 44,45 at a normal compression ratio when the cam guide device 12b occupies the position illustrated in Fig. 1. By the full line there is indicated a centre space 44'' between the piston heads of the pistons 44,45 when guide flange 12b' of the cam guide device 12b is pushed to the maximum upwardly against the shoulder surface lie of the piston rod 11. The engine 10 is shown divided up into three stationary main components, that is to say a middle member, which constitutes the engine block 17 and two Printed from Mimosa 09/23/1999 11:37:41 page -17- 5 10 15 20 25 30 WO 98/49436 PCT/N098/00126 16 cover-forming housing members 17a,17b which are arranged at a respective one of the ends of the engine 10. The housing members 17b, 17c are consequently adapted to cover their respective cam guide devices 12a,12b, support wheels 53 and 55 and their associated bearings in respective piston rods 48,4 9 at their respective end of the engine block 17. All the driving and driven components of the engine are consequently effectively enclosed in the engine 10 and received in an oil bath in the associated lubricating oil chambers 17c and 17d. In the engine block 17 in the illustrated embodiment, there is used in connection with a three cylinder engine, correspondingly designed with three peripherally separated engine cylinders 21. Only the one of the three cylinders 21 is shown in Fig. 1, la and lb. The three cylinders 21, which are placed around the drive shaft 11 with a mutual angular spacing of 120°, are designed according to the illustrated embodiment as separate cylinder-forming insert members, which are pushed into an associated bore in the engine block 17. In each cylinder/ cylinder member 21 there is inserted a sleeve-shaped cylinder bushing 23. In the bushing 23 there is designed, as shown further in Fig. la and lb (see also Fig. 2 and 3), an annular series of scavenging ports 24 at one end of the bushing 23 and an annular series of exhaust ports 25 at the other end of the bushing 23. Equivalently in wall 21a of the cylinder 21 there are arranged scavenging ports 26, which are radially aligned with scavenging ports 24 of the bushing 23, as is shown in Fig. 2, while exhaust ports 27, which are radially aligned with exhaust ports 25 of the bushing 23, are equivalently designed in the cylinder wall 21a, as is shown in Fig. 3. In Fig. 1 there is shown an annular inlet duct 28 for scavenging air, which surrounds the scavenging ports 26, and a scavenging air intake 29 lying radially outside. Printed from Mimosa 09/23/1999 11:37:41 page -18- 5 10 15 20 25 30 WO 98/49436 PCT/N098/00126 17 As is shown in Fig. 2 the scavenging air ducts 28 extend at a significant oblique angle u relative to a radial plane A through the cylinder axis, specially adapted to put the scavenging air in a rotational path 3 8 internally in the cylinder 21, as is shown by an arrow B in Fig. 2. There is further shown in Fig. 1 an annular exhaust outlet duct 30, which surrounds the exhaust ports 27, plus an exhaust outlet 31 emptying radially outwards. In Fig. 3 there is shown an equivalent oblique run of the exhaust ports 27 at an angle v relative to the radial plane A through the cylinder axis, specially adapted to lead the exhaust gases from the rotational path 38 internally in the cylinder in an equivalent rotational path outwards from the cylinder 21, as is shown by an arrow C. The exhaust ports 27 are shown opening radially outwards to facilitate the outward flow of the exhaust gas from the cylinder 21 outwards towards the exhaust outlet duct 30. In the conventionally known manner the scavenging air is used to push out exhaust gas from a preceding combustion phase in the cylinder, in addition to supplying fresh air for a subsequent combustion process in the cylinder. In this connection there is employed according to the invention in a manner known per se a rotating air mass as shown by arrows 38 (see Fig. la and 4a) in working chamber K of the cylinder 21 in the compression stroke. In Fig. la,lb and 4a there is shown a fuel injector or nozzle 32 received in a cavity 33 in the cylinder wall 21a. The injector/nozzle 32 has a pointed end 32' (see Fig. 4a) projecting through a bore 34 m the cylinder wall 21a. The bore 34 passes through the cylinder wall 21a at an oblique angle, which is not marked further in Fig. 4a, but which corresponds to the angle u, as shown in Fig. 2. The pointed end 32' projects further through a bore 3 5 in the bushing 23, in alignment with the bore 34. Mouth 36 (see Fig. 4a) of the nozzle/injector 32 is arranged so Printed from Mimosa 09/23/1999 11:37:41 page -19- 5 10 15 20 25 30 WO 98/49436 PCT/N098/00126 18 that a jet 37 of fuel can be directed, as is shown in Fig. 4a, obliquely inwards in a rotating mass of air as shown by the arrows 38 in cylinder 21, just in front of a spark plug 3 9 (possibly ignition pin) arranged m a chamber zone which forms a part of the combustion chamber K1 (see Fig. lb) . In Fig. 4b there is shown an alternative construction of the solution as shown in Fig. 4a, there being employed in addition to a first fuel nozzle 32 and a first ignition arrangement 39 a second fuel nozzle 32a and a second ignition arrangement 39a in one and the same disc-formed combustion chamber Kl. Both the nozzles 32 and 32a are designed correspondingly as described with reference to Fig. 4a and both the ignition arrangements 39 and 39a are corresponding as described with reference to Fig. 4a. In the nozzle 32a the associated components are designated with the reference designation "a" in addition. In the illustrated embodiment of Fig. 4b the nozzles 32,32a are shown mutually displaced an angular arc of 180°, while the ignition arrangements 39,39a are correspondingly shown mutually displaced an angular arc of 180°. In practice the relative spacings can be altered as required, that is to say with different mutual spacings, for instance depending upon the point of time of the mutual ignition, and the like. Further there is indicated in Fig. 1 a cooling water system for general cooling of the cylinder 21. The cooling water system comprises a cooling water intake not shown further having a first annular cooling water duct 41 and a second annular cooling water duct 42. The ducts 41,42 are mutually connected via an annular series of axially extending connecting ducts 43 (see Fig. 3). The axially extending ducts 43 pass through the cylinder wall 21a m each intermediate zone 27a between the exhaust ports 27, so that these zones 27a especially can be prevented from superheating by being subjected locally to a flowing through of cooling medium. The discharge of cooling water, Printed from Mimosa 09/23/1999 11:37:41 page -20- 19 which is not shown further m Pig. 1, is connected to the cooling water duct 42 remote from tne cooling water intake, m a manner not snown furtner. Internally m the ousnmg 23 tnere are two axtallv movaole pistons 44,45 movaole towards and away from eacn other. Just by the respective top 44a,45a of the piston and by the skirt edge 44b, 45b of the piston there is arranged a set of piston feathers m a manner known per se. The pistons 44,45 are movable synchronously towards and away from eacn other m a two cycle engine system. Further details of the pistons are shown m Fig. 5h. The piston 44 is shown m the form of a relatively thm-walled cap having top portion 44a and skirt portion 44b. Innermost m the internal hollow space of the piston there is arranged a support disc 44c, thereafter follows a head memoer 4 8c for an associated piston rod 48, a support ring 44d and a clamping ring 44e. The neaa memoer 4 8c is provided with a convexly rounded top surface 4 8c' and concavely rounded off bottom surface 48c'', while the support disc 44c is designed with an equivalent concavely rounded upper support surface 44c' and tne support ring 44d is provided with a convexly rounded lower suooort surface 44d'. The neaa member 4 8c is consequently adapted to oe tilted about a theoretical axis relative to tne piston controlled by the support surfaces 44c' and 44d' . By abutment against a shoulder portion 44f internally m tne piston the ring 44e provides for the nead memoer -rSc - and thereby tne ciston rod 4 8 - having a certain degree of fit and thereby a certain possibility of turning aoout said theoretical axis of tne piston 44 The nead memoer 4 8c is orovided witn a middle, sleeve-snaped carrying portion 48g having rib portions 4 8g' projecting laterally outwards wnicn form a locking engagement with equivalent cavities (not snown further) internally m the associated piston rod 48 (see Fig. la and lb) . — AMENDE;, 3*i?'£7 intellectual property office of nz., Receiver 2 3 feb 2001 In Fig. la the pistons 44,45 are shown m their equivalent, one outer position. This outer position, where tnere is a maximum spacing between the pistons 44,45, is designated r.erem generally as a dead point Oa for the piston 44 and Ob for the piston 45. In tne said dead point positions Oa and Ob the piston 44 uncovers the scavenging ports 24, while the piston 45 uncovers -he exhaust ports 25, opening and closing of the scavenging ports 24 being controlled by positions of the piston 45 m the associated cylinder 21, while opening and closing of the exhaust ports 25 is controlled by positions cf the piston 44 m the associated cylinder 21. This control will be described m more detail m what follows having regard to Fig. 12-14. In addition this control will be described with additional effects naving regard to the afore-mentioned regulation cf the cam guide device 12b along the drive When the pistons 44, 45 occupy their opposite outer positions, where there is a minimal spacing between, as is shown m Fig lb, these positions are usually designated as dead point positions. However according to one embodiment of the present invention the pistons 44,45 are stationary, that is to say •"itnout cr broad!v speaking without axial movement relative to each ctner m and at tnese dead point cesitions. In tnat tne pistons are held stationary not onlv m me dead point position, out also m adjacent tortions cf tne respective "sine" - plane, as will be described furtner oelow, a volumetncally more or less constant 'vorjcmg memoer fcomoustion chancer) over a certain arcuate lenctn can oe ensured, tnat is to say over i consideraolv Loneer portion of the "sine" - plane than -:n own n i me r t o. ConseouentIv me pistons 44,45 are at rest or broac.lv speaKina at rest over a portion of the "sine" - plane, wr.im is designated nerem as a "dead por and as a "dead portion" 4b fo 5HEFT x7 <-y i,"v Sacr. dead portions 4a and 4b are furtner illustrated m Fie. 12 and 12 In s£id dsad cor*~ions cnsrs is dsfmsd in 1110 wcr.cr.-—»-a^ s^-c-l—ad "dead s"cs.cs11 , wr.icr. ne^ram (101* reasons wnicn will ce evidenu from wnar follows] is = designated as ens combustion cnamoer KL. The combustion chamber K1 is according to one embodiment of the invention mainly defined in and at a transition portion oetween the compression phase and expansion phase of ths two cycle engine, as will be 10 described m more derail m what follows. During ths expansion pnase, than is co say from ths position of the piston as shown m Fig. lb to tne position of the piston as snown m Fig. la, the working chamber K 13 expanded from a minimum volume, shown py ths comousticn 15 cnamoer KI, gradually to a maximum vclums, as shown m Fig. la and at said dead point Oa and Ob in Figs. 12 and 13, tne compustion chamcer Kl being gradually sxpanasd with another cr.amosr K2 m which ths expansion and compression 5trc.<es of the pistons 44,45 take place. 2G According to one embodiment of the invention the combustion chamber Kl is dsfmsd to a considerable decree m said dsad portion/dead space In practics nowever tne compustion can also continue a bit ;ust cutsids said dsad space, -- sometning wmcn will be explained m more dstail bslow. In connection \'itn ths cnange of the compression ratio m tne wor.-cmg cnamnsr tnsre can pe a cruestioi! m me position as snowr. m Fig. 10 apout different volumes m tne compustion champsr KI all according to whicn j0 regulation is effected durmc use cf ths encme. Frcrr. tns aoove tnere snculd m tnat case also oe a question apout different volumes m tns compustion cnampsr m ths opposite position as snown m Fig. la. However one must bs awars of the piston strokes for 25 tns individual piston 44,^5 being precisely equally long under all operative conditions, reaardless of tns compression ratio vr.ich must be emploved. J INTELLECTUAL PROPFj?tv" OFFICE OF N.Z. i.iL-r 2 3 feb 2001 Received 22 According to one embodiment of the invention the combustion chamber Kl is defined to a considerable degree m said dead portion/ dead space. In practice nowever the combustion can also continue a tit just outside said dead space, something wnicn will be explained m more detail below. Each piston 44,45 is rigidly connected to its respective pipe-shaped piston rod 48 and 49, which is guided m a rectilinear movement via a so-called cross-head control 50. The cross-head control 50 is arranged partly m tne engine blocx. 17 and partly m the respective cover member 17a and 17b at the equivalent free outer end of tne respective piston rod 48,49. The cross-head control 50, which is shown m detail m Fig. 5a, forms an axial guide for tne piston rod 48 and 49 just within and just outside the engine block 17. With reference to Fig. 5a there is a rotary pm 51 wmcn is fastened at one end of the pipe-snaped piston rod 4 3 and which passes througr. tne piston rod 48 crosswise, tnat is to say tnrougn its pipe hollow space 52. On a -iddle portion 51a cf tne rotary pm 51, that is to say internally in said nollow space 52, there is rotatablv mounted a main castor 53, while on one end portion 51b cf tne rotary pm 51 or. the outwardly facing side 48a of the piston rod 4 8 tnere is rotatably mounted an auxiliary The nam castor 53 comprises an inner hub portion 53a r.avmg a roller bearing 53d ana an outer rim portion 53c. The rim portion 53c is provided witn a double curved, that is to say ball secter-snaped roller surface 53c'. The auxiliary castor 5 5 has a construction corresponding to me nam castor 5 3 and comprises an inner hub portion 55a, a middle roller bearing 55b and an outer rim portion 55c witn ball sector-shaped roller surface 55c' . The mam castor 53 is adapted to be rolled off along a roller surface 54 concavely curved m cross-section, wnich forms a part of a so-called "sine" - cur AME.\'D3D SHEET WO 98/49436 PCT/N098/00126 23 shown in Fig. 6 - 8. By employing a ball sector-shaped roller surface 53c', which rolls along an equivalently curved guide surface 54 of the cam guide device 12a and 12b, an effective support abutment can be ensured between 5 the castor 53 and the guide surface 54 under varying working conditions, and possibly with a somewhat obliquely disposed castor and/or obliquely disposed piston rod 48 (49) , such as this being able to be permitted in the pivotable 10 mounting of the piston rod 48 in the piston 44, as shown in Fig. 5h. The "sine" - curve 54' is designed in the cam guide device 12a and 12b of the drive shaft on a side facing equivalently axially outwards from the intermediate 15 cylinder's 21. The auxiliary castor 55 is adapted to be rolled off against and along an equivalent, other "sine" -curve (not shown further) concavely curved in cross-section along a roller surface 56a in a roller path, which is designed in the cam guide device 12a (and 12b) radially 20 just within the roller surface 54. In the embodiment illustrated m Fig. 5a the "sine" -curve 54a' is placed radially outermost, while the "sine" curve 56a' is placed in the cam guide device 12a a distance radially within the "sine" - curve 54a'. 25 Alternatively the "sine" curve 54a' can be arranged radially within the "sine" - curve 56a' (in a manner not shown further). In each of the cam guide devices 12a and 12b there are designed a corresponding pair of "sine" - curves 54a', 30 56a' ma manner not shown further and each "sine" - curve can be provided with one or more "sine" - planes as required. In Fig. 1 schematic reference is made to a cam guide device 12a and 12b, while the details in the associated 35 "sine" - curves and "sine" planes are shown further m Fig. 9-14. Printed from Mimosa 09/23/1999 11:37:41 page -25- WO 98/49436 PCT/N098/00126 24 The "sine" - concept Generally the "sine" - concept can be applied with an odd numbered number (1,3,5 etc.) of cylinders, while an even numbered (2,4,6 etc.) number of "sine" - planes is 5 employed and vice - versa. In a case where there is employed in each of the cam guide devices 12a and 12b a single "sine" - plane (having a "sine" - top and a "sine" - bottom), that is to say the "sine" - plane covers an angular arc of 360°, it is however 10 immaterial whether an odd numbered or even numbered number of cylinders is employed. Correspondingly with a number of two (or more) "sine" - planes there can for instance be employed a larger or smaller number of cylinders as required. 15 The said case with a single "sine" - plane can be especially of interest for use in engines running rapidly which are driven at speeds over 2000 rpm. According to the "sine' - concept the individual engine can be " internally " 20 geared with respect to speed, all according to which number of "sine" - tops and "sine" - bottoms is to be employed at each 360° revolution of the drive shaft. In other words according to the "sine"- concept both engines can be built precisely in the revolutions per minute 25 region which is relevant for the individual application. Generally the series arranged cylinders of the engine, with associated pistons, of the illustrated embodiment are arranged in specific angular positions around the axis of the drive shaft, for instance with 30 mutually equal intermediate spaces along the "sine" - plane or along the series of "sine" - planes ( the "sine" - curve). For example for a two cycle or four cycle engine numbering three cylinders (see Fig. 6), there can be 35 employed for each 360° revolution two "sine" - tops and two "sine" - bottoms and four oblique surfaces lying between, that is to say two "sine" - planes are arranged after each Printed from Mimosa 09/23/1-999 11:37:41 page -26- 5 10 15 20 25 30 WO 98/49436 PCT/N098/00126 25 other in each cam guide device 12a,12b. Consequently in a four cycle motor four cycles can be obtained for each of the two pistons of the three cylinders with each revolution of the drive shaft/cam guide devices and four cycles for each of the two pistons of the three cylinders in a two cycle engine. Correspondingly for a two cycle engine numbering five cylinders, as is shown in Fig. 9 and 10, there can be employed, for each 360° revolution, a "sine" - curve with two "sine" - tops and two "sine" - bottoms and four oblique surfaces lying between, that is to say two "sine" - planes arranged after each other in each cam guide device 12a,12b, so that in a two cycle engine four cycles are obtained for each of the two pistons of the five cylinders with each revolution. The support rollers of the pistons are placed in the illustrated embodiment with equivalently equal angular intermediate spaces, that is to say m equivalent rotary angular positions along the "sine" - curve, so that they are subjected one after the other to equivalent piston movements in equivalent positions along the respective "sine" - planes. The engine power is consequently transferred from the different pistons 44,45 one after the other via the support rollers 53 in the axial direction for the drive shaft 11 via respective "sine" - curves each with their "sine" - plane, and the drive shaft 11 is thereby subjected to a compulsory rotation about its axis. This occurs by piston rods of the engine being moved parallel to the longitudinal axis of the drive shaft and support rollers of the piston rods being forcibly rolled off along the "sine" - planes. The engine power is thereby transferred in an axial direction from support rollers of the piston rods to the "sine" - planes, which are forcibly rotated together with the drive shaft 11 about its axis. In other words the transfer of motive power is obtained from an oscillating piston movement to a rotational Printed from Mimosa 09/23/1999 11:37:41 page -27- 26 movement cf the drive shaft, the motive power being transferred directly from respective support rollers of tne piston rods to "sine" - planes of tne drive shaft. In Fig. Sa tnere is scnematically illustrated a support roller 53 or. an obliquely extending portion of a "sine" - curve 3a. Axial driving forces are shown from an associated piston 44 having piston rod 48 m the form of an arrow Fa and equivalently in a radial plane decomposed rotational forces transferred to the "sine" - plane 8a snown by an arrow Fr. The rotational forces can be deduced from formula 2: According to one embodiment of the invention one achieves inter alia by means of a particular design of the "sine" - plane, the expansion stroke of the pistons 44,45 - reckoned angularly relative to the rotational arc of trie drive shaft - becoming larger than tne compression strc.-ce of the pistons 44,45. In spite of tne different speeds cf movement of the pistons in opposite directions of movement, a relatively more uniform transfer of motive force to the drive snaft II can hereby oe ensured and m addition a "more ■uniform", tnat is to say more vibration-free running of the engine. In Fig. 5-5 tnere is schematically shown the mode of operation of a three cylinder engine 10, in which only tne one piston is shown of the two cooperating pistons 44,45, illustrated m a planar spread condition along an associated "sine" - curve 54', which consists of two mutually succeeding "sine" - planes, plus the associated mam castor 53 of tne associated one piston rod 48. In eacn of tne Figures 6-8 there is scnematically shown the associated one piston 44 m eacn of three cylinders 21 of tne engine, an equivalent arrangement being employed for tne piston 4 5 at tns opposite end of the cylinders. For the sake cf clarity ths cylmdsr 21 and tne opposite piston 4 5 have beer, ornittsd from Fig. 6 - 8, or: y Fa. tan <p, oiston its oiston rod 48 ana its main castc amemdeo sheet received 2 3 feb 2001 r 27 _ snown. Axial movements of tne piston 44 are illustrated by an arrow 57, wnicr. marks the compression stroke of the piston 44, ana an arrow 53, which marks the expansion stroxe of tne piston 44. The "sine" - curve 54' is shown with a lower roll path 54, wmcn has a double "sine" - plane-shaped contour ana wnich generally guides the movement of the main castor 53 m an axial direction, m that it more or less constantly effects a downwardly directed force from the piston 44 via the mam castor 53 towards the roil path 54 m the expansion stroke and an upwardly directed force from the roll patn 54 via the mam castor 53 towards the piston 44 m the compression stroke. The auxiliary castor 55 (not shown further m Fig. 6 - 8) is received with a sure fit relative to an upper roll path 54b, as is shown m Fig. 5a. For illustrative reasons tne said roil path 56b is shown vertically above the mam castor 53 m Fig. 6 - S, so as to indicate the maximum movement cf the main castor m an axial direction relative to tne roll path 54. In practice it will ce the auxiliary castor 55 wnich controls tr.e possibility for movement of the mam castor 53 axially relative to its roll path 54, as is shown m Fig. 5a. The auxiliary castor 55 is normally not active, but will control movement of tne piston 44 m an axial direction m the instances the mam castor 53 has a tendency to raise itself from the cam-forming roll path 54. During operation lifting of tne mam castor 53 in an unintentional manner relative to the roll path 54 can hereov be avoided. The roil path 55 for the auxiliary castor 55 is, as snown m Fig. 5a, normally arranged m the fixed fit spacing from the associated roll path 55a. In Ficr. 5 - S the sine curve 54' is shown with a first relatively steep and relatively rectilinear running curve portion 60 and a subsequent, more or less arcuate, top-forming transition portion/dead portion 61 and a second relatively more gently extending, re 1 atiMw^lectual propfptT"! ' OFFICE of nz y i TENDED SHEET j 2 3 FEB 2001 I RECEIVED I M/ WO 98/49436 PCT/N098/00126 28 rectilinearly running curve portion 62 and a subsequent arcuate transition portion/dead portion 63. These curve contours are however not representative in detail of the curve contours which are employed according to the 5 invention, examples of the correct curve contours being shown in more detail in Fig. 12 and 13. The "sine" - curve 54' and the "sine" - plane 54 are shown in Fig. 6-8 with two tops 61 and two bottoms 63 and two pairs of curve portions 60,62. In Fig. 6-8 there 10 are illustrated three pistons 44 and their respective main castor 53 shown in equivalent positions along an associated "sine" - curve m mutually different, succeeding positions. It is evident from the drawing that the relatively short first curve portions 60 entail that 15 at all times only one main castor 53 will be found on the one short curve portion and two or roughly two main castors 53 on the two longer curve portions 62. In other words with the illustrated curve contour different forms of curve portions can be employed for the compression 20 stroke -relative to the form of the curve portions for the expansion stroke. Inter alia one can hereby ensure that the two main castors 53 at all times overlap the expansion stroke, while the third main castor 53 forms a part of the compression stroke. In practice movement of the piston 44 25 is achieved with relatively greater speeds of movement m the axial direction in the compression stroke than in the expansion stroke. In themselves these different speeds of movement do not have a negative influence on the rotational movement of the drive shaft 11. On the contrary 30 it means one is able to observe that more uniform and less vibration-inducing movements in the engine can be obtained, with such an unsymmetrical design of the curve portions 60,62 relative to each other. Further there is obtained an increase of the time 35 which is relatively placed for disposition in the expansion stroke relative to the time which is reserved for the compression stroke. Printed from Mimosa 09/23/1999 11:37:41 page -30- WO 98/49436 PCT/N098/00126 29 In a practical construction according to Fig. 6-8 there is chosen m a 180° working sequence an arc length for the expansion stroke of about 105° and an equivalent arc length for the compression stroke of about 75°. But 5 actual arc lengths can for instance lie between 110° and 95° when the expansion stroke is concerned and equivalently between 70° and 85° when the compression stroke is concerned. On using for instance a set of three cylinders 21 10 associated with three pairs of pistons 44,45, as is described above, two tops 61 and two bottoms 63 are employed for each 360° revolution of the drive shaft 11, that is to say two expansion strokes per piston pair 44,45 per revolution. 15 On using for instance four pairs of pistons there can be correspondingly employed three tops and three bottoms, that is to say three expansion strokes per piston pair per revolution. In the embodiment according to Fig. 9-10 there is 20 discussed a five cylinder engine with five pairs of pistons, associated with two tops and two bottoms, that is to say with two expansion strokes per piston pair per revolution. Typical cam guide arrangement according to the invention 25 In what follows there will be described with reference to Fig. 9 and 10 in more detail a preferred embodiment of the "sine" - concept according to the invention in connection with a five cylinder, two cycle-combustion engine with two associated, mutually differing 30 cam guide curves 8a and 8b, as shown in Fig. 9 and 10 and in Fig. 12 and 13. In Fig. 14 there is schematically shown a midmost, theoretical cam guide curve 8c, which shows the volume change of the working chamber K from a minimum, as shown 35 in the combustion chamber Kl in the dead zones 4a and 4b, to a maximum, as shown m the maximum working chamber K in the dead points Oa and 0b (see Fig. 9-10 and 12 - 14). Printed from Mimosa 09/23/1999 11:37:41 page -31- nj] '/? ^ - 10 ^ y V'i y <fj o y ' The curve 8b, as is illustrated in Fig. 12 - 14, is shown at the dead point Ob phase-displaced an angle of rotation of 14° m front of the dead point Oa of tne curve 3a. The direction of rotation of the curves 8a ana 8b, tnat is to say the direction of rotation of the drive shaft 11, is illustrated by the arrow E. In Fig. S and 10 there are scnematically illustrated five cylinders 21-1, 21-2, 21-3, 21-4 and 21-5 and belonging to two associated curves 8a and two curves 8b, snown spread m a scnematically illustrating manner m one and the same plane. The five cylinders 21-1, 21-2, 21-3, 21-4 ana 21-5 are shown m respective angular positions witn a mutual angular space of 12°, that is to say m positions wmcn are uniformly distributed around the axis cf the rotary shaft 11. In Fig. 12 there is shown a first curve 8a, which covers an arc lengtn of 18 0° from a position 0°/3 5 0° to a position 130°. A corresponding curve 3a (see Fig. 9) passes ever a corresponding arc length of 130° from position 180° to position 3 6 0°. In other words two succeeding curves 8a for eacn 3 5 0° revolution of the drive shaft. The curve 8a snows in position 0°/360° a first dead point 0a. From position 0° to a position 3 8.4° there is shewn a first transition portion la, wnich corresponds to a first part of a compression stroke and from position 33.-sJ to position 53.2° an ooiiquely (upwardly) extending rectilinear portion 2a, wnich corresponds to a mam part of tne compression seroke ana from position 59.2° to a position "5° a second transition portion 3a, which corresponds to a finishing part of the compression stroke. Thereafter from the position 75° to a position 85° tnere is snown m connection with a second dead point a rectilinear dead portion 4a, wmcn is shown passing over an arc lengtn cf 10°. ( From the position 85° to a position 95.8° the'£4£eiifs;TUAL propfptv / office of nz snown a transition portion 5a, from the position! 95.8° to a / 2 3 feb 2001 amended sheet RECEIVED 31 position 150° an oblique downwardly extending, rectilinear portion 6a and from the position 160° to a position 180° a transition portion 7a. The three portions 5a,5a, 7a togetner constitute an expansion portion. In position 180° is shown anew the dead point Oa and thereafter the cam guide curve continues via a second corresponding curve Sa, from the position 130° to the position 3 50°, tnat is to say with two curves 8a which togetner extend over an arc length of 3 60°. In Fig. 13 there is shown an equivalent (mirror image) curve contour for the remaining curve 8b, shown witn a dead point 0b and succeeding curve portion lb-7b. There is snown the dead point 0b in a position 346°, - the curve nortion lb between the Dositions 34 6° and 1 C 5 0°, O - the curve portion 2b between the positions 3° and - the curve portion 3b between tne positions 60° and - tne curve tcrtion 4b between the oositions 75° and 0°, - tr.e curve portion 5b between the positions 80° and 101.5°, - tne curve portion 5b between the positions 101.5° and 14 6° and - tne curve tcrtion 7b between the positions 14 6° ana 13 5-, tnat is to say with the dead point 0b snown anew m tne position 165°. The cam guide continues witn a corresponding curve 8b oetween tne positions 155° and 345° (see Fig. 10) . The first curve Sa \Fig. 12) controls opening ■.position 150°/340JN ana closing (position 205°/25°) of exnaust ports 25. The second curve 8b iFig. 13) control opening iDosition 145°/325°^ and closing (oosition 185°/5^—eS , ,ntelactual property scavenging ports 24. i office of nz A ? *»■" s t~"\r *"• 'N'.~r""T HivicK Ju onir1 I 3 FEB 2001 Received WO 98/49436 PCT/N098/00126 32 10 15 In Fig. 14 there is shown a phase-displacement of 14° between the dead points Oa and Ob, in the illustrated, schematic comparison of the curves 8a and 8b. Curve 8b, as shown by broken lines in Fig. 14, is for comparative reasons shown in mirror image form relative to the curve 8a, which for its part is shown in full lines in Fig. 14. By chain lines there is shown the midmost, theoretical curve 8c, which illustrates a curve contour approximately like or more like a mathematical "sine curve" - contour. In Fig. 9 and 10 there is shown the "sine" - plane 8b in a position 14° in front of the position for the "sine" -plane 8a. The five said cylinders 21-1, 21-2, 21-3, 21-4 and 21-5 are shown in successive positions relative to the associated "sine" plane and individually in successive working positions, as shown in the following diagram 1 and diagram 2. 20 Diagram 1 with reference to Fig. 9 and Fig. 12 - 13. "Cylinder No Angle Position Working Position Exhaust Ports Scavenging Ports Curve Zone 8a/8b 25 30 21-1 21-2 21-3 21-4 21-5 3°/183° 75°/255° 147°/327° 219°/39° 291°/101° compression compression expansion compression expansion closed closed closed closed closed open* closed closed closed closed la/lb 4a/4b 6a/7b 2a/2b 5b/6a * The scavenging ports 24 open in position 160°/34 0° and close in position 25°/205°, that is to say the scavenging ports 24 are held open over an arc length of 45°. 35 The exhaust ports 25 are held on the other hand open over an arc length of 39°, that is to say over an arc length which is phase-displaced 14° relative to the arc length in which the scavenging ports are open (see Fig. 14) . 40 The scavenging ports 24 can consequently be open over an arc length of 20° (see the curve portions la - 3a in Fig. 12 and the single hatched section A' in Fig. 14) Printed from Mimosa 09/23/1999 11:37:41 page -34- 5 10 15 20 25 30 35 WO 98/49436 PCT/N098/00126 33 after the exhaust ports 25 are closed. This means that the compression chamber over the last-mentioned arc length of 2 0° can inter alia be supplied an excess of scavenging air, that is to say is overloaded with compressed air. Diagram 2 with reference to Fig. 10 and Fig. 12 - 13. Cylinder Angle Working Exhaust Scavenging Curve No Position Position Ports Ports Zone 8a/8b 21- 1 21°/201° compression closed closed la/2b 21- 2 93°/273° expansion closed closed 5a/5b 21- 3 165°/345° expansion open** open* 7a/7b 21- 4 2370/570 compression closed closed 2a/2b 21- 5 309°/129° expansion closed closed 6a/6b ** The exhaust ports open in position 146°/326° and close in position 185°/5°, that is to say the exhaust ports 25 are open over an arc length of 39°. From Fig. 14 it will be evident from the marked off, individual hatched sections B' that the exhaust ports 25 can be held open over an arc length of 14° before the scavenging ports 24 open. The said sections A' and B' show the axial dimensions of the exhaust ports 25 and the axial dimensions of the scavenging ports 24 in a respective outer portion of the working chamber K. The ports 24 and 25 can thereby be designed of equal height in each end of the working chamber K. The said height is shown in Fig. 12 -14 by X2. In an angle zone of 5° (from position 75° to position 80° - see especially Fig. 13) of the "sine" - plane 8b and in an angle zone of 10° (from position 75° to position 85° -see especially Fig. 12) of curve 8a, the respective associated piston 44 and 45 is held pushed in to the maximum with a minimum spacing X of for instance 15 mm between the piston head 44a and the middle line of the working chamber. With reference to Fig. 12 it must further be observed that over an arc length of 36.6°, from position 59.2° to position 95.8°, the spacing between the piston heads is Printed from Mimosa 09/23/1999 11:37:41 page -35- changed relatively little. The spacing from the piston neaa 44a to the middle line 44' is changed from a minimum A = 15 mm (in the dead portion 75°-80°) to a 20 mm spacing (A*)(position 93° Fig. 11). Correspondingly tne spacing from ths piston head to tne middle line 44' is cnanged from a minimum X = 15 mm in the dead portion 75°-80° to a 25mm spacing (X**) in position 57° Fig. 13. Over said arc length cf 3 5.5°tne volume m the combustion chamber Kl is kept approximately constant between the oistons 44,45. Combined effects of two ohase-displaced "sine" - olanes From Fig. 14 ths contours of the respective two curves 8a,3b, which are shewn schematically m mirror image relative to each other will be evident. Curve 8b is snown real with a full line, while curve 8b is shown with a brojeen line, m mirror image about a middle axis between the pistons 44,45. The curve 3c shows a tneoretical -idrnost curve between the curves 8a, 8b. It will be evident tnat tne midmost curve Sc nas a contour wnicn lies more closely up to a sine curve contour than the contours of tne curves 8a,8b individually. Consequently, even if one gets a relatively unsymmetncal contour m the curves 3a,3b mutually, a relatively symmetrical contour of the midmost curve 8c can be acnieved. ~j_o2 At tne close cf the compression phase in curve zone 3a ana 3b the fuel is injected m a jet with a flow into tne rotating scavenging air current ana is mixed/atomised effectively m the rotating scavenging air current. Ignition starter: Immediately after the infection of fuel that is to say at tne close cf tne compression pnase electronically controlled ignition is mitiatea m curve zone and 3b. Provision being made for effective rotation of t]rl^'r%l^Si[^A'-r.p^OPERTY 31 1 OrrlCE OF N Z. mixture cf scaver.cmg air and fuel m a fuel clqud psst j 2 3 feb 2001 W&'DZD SHEET RECEIVED the ignxtion arrangement. One can aim with advantage at an ignition delay of 7-10% relative to the conventional ignition angle. Combustion onase In tne illustrated embodiment tne combustion starts immediately after ignition and is accomplished mainly ever a limited region m which tne pistons roughly occupy a maximum pusnea m position, tnat is to say at tne close cf tne curve zone 3a,3b, that is to say in a region where tne pistons are subjected to minimal axial movement. The combustion proceeds mainly or to a significant extent where the pistons 44,45 are held at rest m the inner dead portion 4a ana 4b, tnat is to say over an arc length of 10° and 5° respectively. However tne combustion continues as recuired to a greater or smaller degree m the following transition portion 5a,5b and m the main expansion portion 5a,6b, depending upon the speed of rotation of the rotary shaft. As a consequence of the rotating fuel cloud m the combustion cnamcer ?IL m tne dead portion 4a, 4b and m that one can Keep tne flame front relatively short in the disc-shaped combustion cnamber Kl, there can be ensured m all instances fuel ignition for a mam bulk of the fuel cloud m tne combustion chamber Kl, that is to say within said dead portion -ra,4b. In practice the combustion cnamber can be allowed to be expanded to the portion 5a, 5b ;ust outside tne dead portion 4a,4b with largely corresponding advantages m a defined volume of tne worKing cnamber K. £oeed of combustion The steed of combustion is as known of an order of magnitude cf 20 - 13 meters per second. 3y tne application of a double set of fuel nozzles ana a corresponding double set of ignition arrangements distributed ever eacn quarter of tne penpneral angle of the worKing chamber (see Fig. 4b) tne combustion area can be effectively covazf^S^&fe'SL PROPERTY ] OFFICE OF NZ the whole of the disc-shaoed combustion cnambei Kl. m J 2 3 FEB 2001 ... , . received WO 98/49436 PCT/N098/00126 36 practice especially favourable combustion can thereby be achieved with relatively short flame lengths. Optimal combustion temperature: As a result of the concentrated ignition/combustion 5 zone 3a,3b which is defined in the chamber K just in front of the combustion chamber Kl and the region 5a,5b immediately after the combustion chamber Kl, that is to say in a coherent region 3a - 5a and 3b - 5b, where the pistons 44,45 are at rest or largely at rest, it is 10 possible to increase the combustion temperature from usually about 1800°C to 3000°C. It is possible thereby to achieve an optimal (almost 100%) combustion of the fuel cloud even before the pistons 44,45 have commenced fully the expansion stroke, that is to say at the end of the 15 curve portions 5a,5b. Ceramic ring Provision is made for a ceramic ring, that is to say a ceramic coating applied in an annular zone of the working chamber K corresponding to a combustion region (3a 20 - 5a,3b,5b), so that high temperatures can be employed especially in the combustion chamber Kl, but also in the following portion 5a,5b of the combustion region. The ceramic ring which is shown with a dimension as indicated by a broken line 70 in Fig. 12 - 14, comprises the whole 25 combustion chamber Kl and is in addition extended further outwards in the combustion chamber over a distance 13. Introductory Expansion Stroke After at least considerable portions of the fuel are consumed in the afore-mentioned combustion region (3a -30 5a, 3b,5b) and one has just started the expansion stroke there are generally optimal motive forces. More specifically this means that by way of the cam guide along the curves 8a and 8b there is obtained an optimal driving moment immediately the expansion stroke commences in the 35 transition region 5a,5b and increases towards a maximum in the transition region 5a,5b. The driving moment is maintained largely constant in the continuation of the Printed from Mimosa 09/23/1999 11:37:41 page -38- 3 7 - rJ.1 ?? i& // expansion stroke (in the rsgion 6a, 6b) ana at least in tne'' beginning of this region, as a consequence of possible after cum of fuel m cms region m spice of tne volumetric expansion wmcn occurs gradually m che cnamber K as cne expansion stroxe proceeds forward cnrough this. Expansion Phase According co cne illuscrated embodiment the compression phase tax.es place relative to the curves Sa,Sb under angles of mclmacicn of between abour 25° and abcuc 3 6° m the respective two curves 8a and 8b, that is to say wich a mean angle (see Fig. 14) of about 20°. If desired che angles of inclination (ana the mean angle) can for instance be increased to about 4 5° or more as required. The expansion phase taxes place correspondingly m tne illustrated embodiment at between about 22° and 27° m the two curves 3a and Sb, tnat is to say while at a mean angle (see Fig. 14) cf about 24°. As a result of tne relatively steep (mean) curve contour cf 2 0° m the compression pnase and the relatively gentler contour 24c m the expansion pnase, tnere is acnieved a particularly favourable increase of the durability m time cf tns expansion stroxe relative to tne durability of tne compression stroke. One can by means of said unsymmetrical relationsnip between the speed of movement m the compression stroxe ana the speed of movement in the expansion stroke, displace tne start of the combustion process m the compression pnase closer up to the inner dead point ana cnerebv time-displace a larger part of tne combustion process to tne beginning of the expansion pnase, witnout tnis r.avmg negative consequences for the combustion. Consequently there can be acnieved a better control and a more effective utilisation of the motive force of cne fuel combustion m tne expansion phase tnan Hitherto. Inter alia chere can be displaced pN^EjALimpEm possibly occurring, anconcrolled combustion i rom°t'KS OF Nz compression pnase ever the dead point to the expgi&fpq 2001 WO 98/49436 PCT/N098/00126 38 phase and thereby convert such " pressure points", which involve uncontrolled combustion in the compression phase, to useful work in the expansion phase. 5 By extending the expansion phase at the expense of the compression phase a relatively higher piston movement is obtained in the compression phase than in the expansion phase. This has an influence on each set of pistons of the combustion engine in every single working cycle. 10 Rotation effect in the working chamber There is established rotation of the gases in the working chamber by ejecting exhaust gases via obliquely disposed exhaust ports 2 5 (see Fig. 2) followed by the injection of scavenging air via the obliquely disposed 15 scavenging air ports 24 (see Fig. 3). There is set up thereby a rotating, that is to say helical gas flow path (see arrow 38 in cylinder 21 -1 in Fig. 9) which is maintained over the whole working cycle. The rotational effect is reactivated m the course of the working cycle, 20 that is to say during the infection, ignition and combustion phases. There is consequently supplied a new rotational effect to the gas flow 38 during transit in the working cycle by fuel infection via the nozzle 36 and subsequent 25 fuel ignition via the ignition arrangement 39, the attendant combustion producing a direction fixed flame front with an associated pressure wave front roughly coinciding with the gas flow 38 already established. The rotational effect is consequently maintained during the 30 whole compression stroke and is reactivated during transit by injecting fuel via an obliquely disposed nozzle jet 37, as shown in Fig. 4a, via a corresponding obliquely disposed nozzle mouth 36. Additional rotational effects are obtained in the combustion phase. 35 A still additional increase of the rotational effect can be obtained according to the construction as shown in Fig. 4b by the application of an extra (second) fuel Printed from Mimosa 09/23/1999 11:37:41 page -40- nozzle 3 7a, whicn is disposed angularly displaced relative to tne first fuel nozzle 37, and by the application cf an extra ignition arrangement 3 9a, wmcn is disposed angularly displaced relative to tne first ignition arrangement 39. When the exnaust ports 25 open again, on the termination of tne worKing cycle, the exhaust gas is exhausted with a nigh speed of movement, that is to say with a hign rotational speed, during exhaustion of exhaust gas via the said obliquely disposed exnaust ports. Further the rotational effect for tne exnaust gases is maintained immediately tne obliquely disposed scavenging ports 24 open, so tnat the residues of the exnaust gases are scavenged with a rotational effect outwardly from the worKing chamber K at the close of tne expansion phase and tne becinning of tne compression phase. Thereafter the rotational effect is maintained, after closing of the exhaust ports, the scavenging ports being continued to be neid open over a significant arc lengtn. Regulation of tne compression ratio of tne engine dunnc It is possible to regulate tne volume between pistons 44,45 of the cylinder 21 by regulating tne mutual spacing between the pistons 44,45. It is hereov possible to directly regulate tne compression ratio m the cylinder 21 as recruired, for instance during operation of the engine bv means of a simple regulation tecnnicue adapted according to the "sine" - concept. It is especially interesting according to tne invention to change the compression ratio m connection witr. starting up tne engine, that is to say on cold start, relative to a most favourable compression ratio possible during usual operation. But it can also be of interest to cnange tne compression ratio during operation for various otr.er reasons . A constructional solution for sucn a ation accordma to the invention is based on oressu|r^TSi5PI'r[A1- PROPERTY j j "OFFICE OF N.Z. controlled regulating tecnnicue. Alternative If/ there can f 2 3-feb 2001 AMENDED SHEET Q r „ RECEIVED ft r i* e ' a r • r ( be employed for instance electronically-controlled regulating cec.nJ.ique, wilier, is not shown further herein, for regulating the compression ratio. Alternatively there can be employed a corresponding regulating possibility also for the piston 45 by replacing the cam guide device 12a with a cam guide device correspondingly as snown for the cam guide device 12b. It is apparent that it is possible to regulate the position of both pistons 44,45 m the associated cylinder via their respective cam guide arrangement with their respective separate possibility of regulation, m a mutually independent manner. It is also apparent that the regulation of the position cf the pistons in the cylinder can be effected syncnronouslv for tne two pistons 44,45 or individually as reauired. In Fig. 15 and 15 there is snown schematically an alternative solution of certain details m a cam guide device, as it is referred to herein bv the reference numeral 112a, and cf an associated piston rod, as shown by tne reference numeral 14 3 as well as a pair of pressure soneres, as shown ov tne reference numerals 153 and 155. The cam cruide device 112a: In tne construction according to Fig. 1 the cam guide device 12a is shown having a relatively space-demanding design witn associated casters 53 ana 55 arranged at the side of eacn otner m the radial direction of tne cam guide device 12a, that is to say with the one caster 53 arranged radially outside tne remaining caster 55 and with tne associated "sine" - grooves 54,55c illustrated correspondingly radially separated on each of their radial prOj ecticns In tne alternative construction according to Fig. 15 and 15 the cam guide device 112a is shown with associated pressure soneres 153, 155 arranged m succession m the axial direction cf tne cam guide device 112a, Jt/b$aT,c-f»7^s mnltllectual property say with a sonere on each respective side of an iSi2S.gei©f nz. i 2 3 feb 2001 Ai-NDED SHEET | RECEIVED r -} Z- x V'V; 4/ isf I.W-/ ■* 41 dual, common projection, illustrated m the form of an intermediate annular flange 112. The annular flange 112 is snown witn an upper "sine" - curve forming "sine" - groove 154 for guiding an upper pressure sphere 153, w'nicr. forms tne mam support spnere of the piston rod 148, ana a lower "sine" - curve forming "sine" - groove 155a for guiding a lower pressure sphere 155, whicn forms the auxiliary support spnere cf the piston rod 148. The grooves 154 ana 155a have, as shown m Fig. 15, a laterally concavely rounded form corresponding to the spherical contour of the spneres 153,155. The annular flange 112 is shown having a relatively small thickness, but the small thickness can be compensated for as to strength m that the annular flange 112 has m the peripneral direction a self-reinforcing "sine" - curve contour, sucn as indicated by the obliquely extending section cf the annular flange illustrated m Fig. 15. In Fig. 15 the annular flange 112 is shown segment ally m section, wmle in Fig. 15 there is shown m cross - section a peripherally locally defined segment of tne annular flange 112, seen from the inner side of the annular flange 112. There can be employed a largely corresponding design of the afore-mentioned details m botn cam guide devices, that is to say also m the cam guide device not shown furtner corresponding to the lower cam guide device according to Fig. 1 The cistcr. rod 148- According to Fig. 1 a pipe-snaped, relatively voluminous piston rod 48 is shown, wmle m the alternative embodiment according to Fig. 15 and 15 there 13 illustrated a slimmer, compact, rod-snaped piston rod 14 8 having a C-snapea head portion 14 8a with two mutually opposite spnere r.clders 148b, 148c for a respective oressure sonere 153,155. The oiston roo. 14 8 can m a manner not snown further be orovidsd with external screw threads which/ '^J&t£€fijBNEe>RopFi?TY 1 office OF NZ witn internal screw tnreaas m the heaa sort Jon, so that ] 2 3 f£B 2001 h'.exdtd shset i I RECEIVED WO 98/49436 PCT/N098/00126 12 the piston rod and thereby the associated sphere holder 148b can be adjusted into desired axial positions relative to the head portion 148a. This can inter alia facilitate the mounting of the sphere holder 148b and its associated 5 sphere 153 relative to the annular flange 112. In Fig. 16 the annular flange 112 is shown with a minimum thickness at obliquely extending portions of the annular flange, while the annular flange 112 can have in a manner not shown further a greater thickness at the peaks 10 and valleys of the "sine" -curve, so that a uniform or largely uniform distance can be ensured between the spheres 153,154 along the whole periphery of the annular flange. By the reference numeral 100 there is referred to 15 herein a lubricating oil intake, which internally in the C-shaped head portion 148a branches off into a first duct 101 to a lubricating oil outlet 102 in the upper sphere holder 148b and into a second duct 103 to a lubricating oil outlet 104 in the lower sphere holder 148c. 20 The pressure spheres 153.155: Instead of the casters 53,55 shown according to Fig. 1, which are mounted in ball bearings, pressure spheres 153,155 are shown according to Fig. 15 and 16. The pressure spheres 153,155 are mainly adapted to be rolled 25 relatively rectilinearly along the associated "sine" - grooves 154,155a, but can in addition be permitted to be rolled sideways to a certain degree in the respective groove as required. The spheres 153 and 155 are designed identically, so that the sphere holders 148a,148b and 30 their associated sphere beds can also be designed mutually identically and so that the "sine" - curves 154,155a can also be designed mutually identically. The pressure spheres 153,155 are shown hollow and shell-shaped with a relatively low wall thickness. There 35 are obtained hereby pressure spheres of low weight and small volume, and in addition there is achieved a certain Printed from Mimosa 09/23/1999 11:37:41 page -44- WO 98/49436 PCT/N098/00126 43 elasticity in the sphere for locally relieving extreme pressure forces which arise in the sphere per se. In Fig. 17 and 18 a pair of guide rods 105,106 are shown which pass through internal guide grooves 107,108 along opposite sides of the head portion 14 8a of the piston rod 148. Printed from Mimosa 09/23/1999 11:37:41 page -45- </div>

Claims

<div class="application article clearfix printTableText" id="claims"> 44 WHAT WE CLAIM IS:

1. Arrangement in a combustion engine having internal combustion, comprising a number of engine cylinders, arranged annularly around a common drive shaft and having cylinder axes running parallel to the drive shaft, each cylinder including a pair of pistons movable towards and away from each other and a common, intermediate working chamber for each pair of pistons, while each piston is equipped with its respective axially movable piston rod, the free outer end of which is supported via a support roller against its respective curve-shaped, i.e. "sine"-like curve shaped, cam guide device, arranged at opposite ends of the cylinder and which controlling movements at the piston relative to the associated cylinder. characterised m that at least one of the cam guide devices is axially displaceable in relation to a one-piece drive shaft and is provided with a hydraulic mechanisme, for separately adjusting m axial direction the position of said at least one cam guide device including regulation of the relative spacing between the pistons, especially for regulation of the compression ratio in the acommon working chamber between the pistons, said hydraulic mechanisme includes an annular pressure oil chamber and a simulator piston, said simulator piston is partitioning said chamber into two sub-chambers, and each sub-chamber is connected to a respective one of two pressure oil circuits. intellectual property office of nz. 2 3 FEB 2001 RECEIVED 45

2. Arrangement in accordance with claim 1, characterised in that the pressure oil chamber is defined in a spacing between the drive shaft and the cam guide device, and said simulator piston is projecting from said cam guide device radially inwardly in said chamber.

3. Arrangement in accordance with claim 1 or 2, characterised m that the simulator piston is passed through parallel to the axis of the drive shaft by a set of driving bolts, which allow a certain axial movement of the simulator piston relative to the drive shaft, while the driving bolts are connected at their respective opposite ends to the drive shaft and connected to a carrying member fastened to the drive shaft.

4. Arrangement in accordance with claim 3, characterised in that the drive shaft is axially extended at its outer end with a radially graduated end portion, which is rigidly connected to the carrying member in the form of a cup-shaped end part, the pressure oil chamber being localised between the drive shaft and the cup-shaped carrying member.

5. Arrangement m accordance with one of claims 3-4, characterised m that an oil guide means, which projects axially through an axial bore in the cup-shaped carrier member and further inwardly into an axial bore in the drive shaft aligned with that is provided with a pair of internal, axially extending pressure oil ducts, which empty radially outwards into their intellectual property OFFICE OF N Z 2 3 FEB 2001 RECEIVED 46 respective associated pressure oil rings which communicate with a pressure oil duct to respective sub-chambers of the pressure oil chamber.

6. Arrangement m accordance with one of claims 1-5, characterised m that said one piston of the cylinder controls opening and closing of one or more exhaust port(s) of the cylinder, and the remaining piston of the cylinder controls opening and closing of one or more scavenging port(s). END OF CLAIMS </div>