ARRANGEMENT IN A COMBUSTION ENGINE WITH INTERNAL COMBUSTION

Abstract: A combustion engine (10) having internal combustion, 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: ARRANGEMENT IN A COMBUSTION ENGINE WITH INTERNAL COMBUSΗON 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 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, the free outer end of which forms via a support roller a support against its curve-shaped, that is to say 'sine'- 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 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 parallel rows and are equipped with pistons synchronously movable in pairs, that is to say the pistons are physically connected to each other in their respective pair of cylinders. There is employed in this connection a middle cam guide device, which is common to each and all of the cylinders of the engine and which jointly controls each pair of mutually connected pistons. In other words 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 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 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 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 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 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 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 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 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 introduced into the cylinder. In the drawings there is shown, in 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 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 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 in the piston and cylinder arrangement according to the 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 in a simple and ready, but at the same time controlled, precise and reliable manner, that is to say the aim is to 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 in that at least the one of the two pistons 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 position to regulate the compression ratio in the working chamber between two pistons of the cylinder by quite 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 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 in the cylinder is adapted to be fixed via the 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 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 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 . 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 in each cylinder with a regulation via one and the same common control arrangement . 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. 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. But by regulating the position only for the one cam guide device the regulation arrangement is rendered especially simple. In addition with such an arrangement of the one cam guide device other significant advantages can be obtained in the general function of the engine, as will be described further below. According to the invention there are consequently possibilities of regulating the working volume between pistons of the cylinders as 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. According to the invention the compression ratio can consequently be regulated by regulating the mutual spacing between the pistons in each cylinder, by quite simply regulating the relative spacing between the cam guide devices. It is possible hereby to regulate the compression ratio of the cylinders of the engine directly as required, independently of the concrete design of the cam guide devices in the finally manufactured condition of the engine. A favourably practical solution according to the invention consists in that the control arrangement is regulatable by means of pressure oil. Preferably the control arrangement comprises an annular pressure oil chamber, which is defined' between the drive shaft and the cam guide device, while a piston- forming compression simulator projects from the cam guide device radially inwardly into the pressure oil chamber and divides this into two chamber portions, that is to say one on each side of the compression simulator, the chamber portions communicating with their respective mutually adapted pressure oil circuits. It is preferred that the cam guide device is fast connected for rotation with the drive shaft and that the compression simulator 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 compression simulator relative to the drive shaft, while the driving bolts are connected at their respective opposite ends to the piston rod. It is especially interesting according to the invention to change the compression ratio in 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 normal operation. Consequently it can be of interest to change the compression ratio during operation of the engine for various reasons. It is preferred according to the invention that the one piston of the cylinder, which is under discussion to regulate the position of in the associated cylinder, constitutes a piston which controls opening and closing of exhaust ports of the cylinder. At the same time as the compression ratio is regulated between the pistons, there is hereby the possibility in addition to regulate the opening and closing 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 in relation to normal operation. When one starts with a cold motor, provision can be made for instance for the said one cam guide device to occupy automatically, for example by temperature sensitisation, the outer position, where there is obtained the highest compression of the engine. This means for instance that the exhaust ports open somewhat delayed and are held open over a shorter period, than with normal operation. On starting the engine there is consequently brought about automatically the achievement of the relatively highest compression at the moment there is the 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 during the operation. According to the invention the temperature in 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 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 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 . 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 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 in 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 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 other group of pistons via their respective separate cam guide devices. The positions which are determined for the cam guide devices axially along the drive shaft can be regulated according to the invention as required singly, that is to say individually, or collectively, for instance during operation of the engine, while the phase displacement between the cam guide devices is determined during the manufacture of the engine by positioning the cam guide devices relative to each other in the peripheral direction around the drive shaft . Consequently the opening and closing of the scavenging ports and the exhaust ports can for instance be achieved according to said phase displacement at different moments and these moments can be determined by equivalent designing of the individual cam guide device. During operation according to the present invention the effect of the said phase displaced opening and closing of for instance the exhaust ports, which is controlled by the one of the cam guide devices, can be oversteered to a certain degree, by changing the relative spacing between the cam guide devices, while during normal operation the conditions can be optimised with a sufficiently heated engine . Further 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 in Fig. lb pistons of the engine in a position with minimal mutual spacing. Fig. 2 shows schematically a first cross-section illustrated at one end of the cylinder of the engine in which there is shown a scavenging air intake. Fig. 3 shows schematically a second cross-section illustrated at the other end of the cylinder of the engine, in which there is shown an exhaust outlet. Fig. 4a shows schematically in a third cross-section, the middle portion of the engine cylinder, where the fuel is supplied and the ignition of the fuel occurs, illustrated in a first embodiment. Fig. 4b shows in 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 the engine according to Fig. lb. Fig. 5b shows a cam guide device with associated drive shaft, illustrated in longitudinal section with a segment of the engine according to Fig. lb. Fig. 5c shows a cross head in side view. Fig. 5d and 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 . Fig. 5h shows a piston according to the invention in vertical section. Fig. 6 - 8 show schematically illustrated and spread in the plane of the drawing a general pattern of movement for a first of two pistons associated with each cylinder, used in connection with a three cylinder engine, and illustrated in different angular positions relative to the rotary movement of the drive shaft . Fig. 6a shows schematically the principle for transferring motive forces between the roller of the piston rod and an associated obliquely extending portion of a "sine" - plane. 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 in connection with a five cylinder engine. Fig. 10 shows in a representation corresponding to Fig. 9, the pistons in respective positions relative to associated cylinders, in a subsequent working position. Fig. 11 shows 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 in each cylinder. Fig. 13 shows a corresponding detailed curve contour for a "sine" - plan for a second piston in each cylinder. Fig. 14 shows a comparative compilation of the curve contours according to Fig. 12 and 13. Fig. 15 shows in section and in longitudinal section an alternative construction of a cam guide device with associated pressure rollers arranged at the outer end of a piston rod. Fig. 16 shows the same alternative solution, as illustrated in Fig. 15, shown in section in a direction radially outwards from the cam guide device. Fig. 17 and 18 show in elevation and in horizontal section respectively the guiding of the head portion of the piston rod along a pair of control bars extending mutually in 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 there is illustrated in particular a combustion engine 10 according to the invention shown in cross-section and in a schematic manner. rt tr Φ μ- fi Hi J CQ rt Φ d μ- d I 3 Φ P ) d CQ . 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 lie 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. 12 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, in 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 in 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 oil 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 Φ tr Oi Ω 0 H tQ ra H PJ ra cr Φ fi Ω CQ ra fi Ω I- 1 Hi I- 1 cr d 0 μ- Φ Hi d J X TJ Φ Hi φ ^ tr Φ tr Φ 0 -J 0 d Φ Q Z Hi d PJ μ- μ- - μ- Φ rt Hi tQ so <: o cr H cr rt μ- Φ Hi rt ra i Oi PJ Ω z Φ d μ- Hi μ- Hi PJ φ 3 ri Z d <! φ μ- 0 0 Φ rt μ- φ Ω d rt Ω rt rt ri 0 μ- μ- Φ Φ Φ fi g 3 d TJ tr Hi φ rt J > φ μ- 1 Hi d H Ω Φ ra fi φ Φ φ d Hi ri so ^ μ- d μ- rt Ω Φ l- 1 CQ PJ <! 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PJ μ- φ CQ TJ ri 3 CQ Hi ι-3 <; rt φ Φ d ra Ω < PJ 3 cr d fi μ- φ tr Ω φ Φ fi 3 o Φ Ω cr Φ Φ Ω d ^ ra *- μ- <! tQ Φ 0 ri ri Φ φ 3 d tr ^ Φ rt d *- ra φ d <! 1 d d φ iQ o μ- ra Oi d ri - Φ μ- Φ P ) rt rt rt d tr PJ Φ it-. m Oi ri tr tr so μ Oi Lπ Φ Φ Φ Hi μ ri rt PJ 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, main 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, in 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 1-2 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 48,49 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. 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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 in 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, 12 which is not shown further in Fig. 1, is connected to the cooling water duct 42 remote from the cooling water intake, in a manner not shown further. Internally in the bushing 23 there are two axially movable pistons 44,45 movable towards and away from each 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 fourths 46 in a manner known per se . The pistons 44,45 are movable synchronously towards and away from each other in a two cycle engine system. Further details of the pistons are shown in Fig. 5h. The piston 44 is shown in the form of a relatively thin- walled cap having top portion 44a and skirt portion 44b. Innermost in the internal hollow space of the piston there is arranged a support disc 44c, thereafter follows a head member 48c for an associated piston rod 48, a support ring 44d and a clamping ring 44e. The head member 48c is provided with a convexly rounded top surface 48c' and concavely rounded off bottom surface 48c' ' , while the support disc 44c is designed with an equivalent concavely rounded upper support surface 44c' and the support ring 44d is provided with a convexly rounded lower support surface 44d' . The head member 48c is consequently adapted to be tilted about a theoretical axis relative to the piston controlled by the support surfaces 44c' and 44d' . By abutment against a shoulder portion 44f internally in the piston the ring 44e provides for the head member 48c - and thereby the piston rod 48 - having a certain degree of fit and thereby a certain possibility of turning about said theoretical axis of the piston 44 during operation. The head member 48c is provided with a middle, sleeve-shaped carrying portion 48g having rib portions 48g' projecting laterally outwards which form a locking engagement with equivalent cavities (not shown further) internally in the associated piston rod 48 (see Fig. la and lb) . In Fig. la the pistons 44,45 are shown in their equivalent, one outer position. This outer position, where there is a maximum spacing between the pistons 44,45, is designated herein generally as a dead point Oa for the piston 44 and Ob for the piston 45. In the said dead point positions Oa and Ob the piston 44 uncovers the scavenging ports 24, while the piston 45 uncovers the exhaust ports 25, opening and closing of the scavenging ports 24 being controlled by positions of the piston 45 in the associated cylinder 21, while opening and closing of the exhaust ports 25 is controlled by positions of the piston 44 in the associated cylinder 21. This control will be described in more detail in what follows having regard to Fig. 12-14. In addition this control will be described with additional effects having regard to the afore-mentioned regulation of the cam guide device 12b along the drive shaft 11. When the pistons 44,45 occupy their opposite outer positions, where there is a minimal spacing between, as is shown in Fig. lb, these positions are usually designated as dead point positions. However according to the present invention the pistons 44,45 are stationary, that is to say without or broadly speaking without axial movement relative to each other in and at these dead point positions. In that the pistons are held stationary not only in the dead point position, but also in adjacent portions of the respective "sine" - plane, as will be described further below, a volumetrically more or less constant working chamber (combustion chamber) over a certain arcuate length can be ensured, that is to say over a considerably longer portion of the "sine" - plane than known hitherto. Consequently the pistons 44,45 are at rest or broadly speaking at rest over a portion of the "sine" - plane, which is designated herein as a "dead portion" 4a for the piston 44 and as a "dead portion" 4b for the piston 45. Such dead portions 4a and 4b are further illustrated in Fig. 12 and 13. In said dead portions there is defined in the working chamber K a so-called "dead space", which herein (for reasons which will be evident from what follows) is designated as the combustion chamber Kl . The combustion chamber Kl is according to the invention mainly defined in and at a transition portion between the compression phase and expansion phase of the two cycle engine, as will be described in more detail in what follows. During the expansion phase, that is to say from the position of the piston as shown in Fig. lb to the position of the piston as shown in Fig. la, the working chamber K is expanded from a minimum volume, shown by the combustion chamber Kl , gradually to a maximum volume, as shown in Fig. la and at said dead point Oa and Ob in Fig. 9 and 10, the combustion chamber Kl being gradually expanded with another chamber K2 in which the expansion and compression strokes of the pistons 44,45 take place. According to the invention the combustion chamber Kl is defined to a considerable degree in said dead portion/dead space. In practice however the combustion can also continue a bit just outside said dead space, something which will be explained in more detail below. In connection with the change of the compression ratio in the working chamber there can be a question in the position as shown in Fig. 10 about different volumes in the combustion chamber Kl all according to which regulation is effected during use of the engine. From the above there should in that case also be a question about different volumes in the combustion chamber in the opposite position as shown in Fig. la. However one must be aware of the piston strokes for the individual piston 44,45 being precisely equally long under all operative conditions, regardless of the compression ratio which must be employed. u> to t μ> μ> LΠ o LΠ O LΠ o LΠ 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 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 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 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 just within the roller surface 54. In the embodiment illustrated in 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' . 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' , 56a' in a 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 "sine" - curves and "sine" planes are shown further in Fig. 9 - 14. 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 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 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. 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 " 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 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 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 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 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 in 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 movement of the drive shaft, the motive power being transferred directly from respective support rollers of the piston rods to "sine" - planes of the drive shaft. In Fig. 6a there is schematically illustrated a support roller 53 on an obliquely extending portion of a "sine" - curve 8a. Axial driving forces are shown from an associated piston 44 having piston rod 48 in the form of an arrow Fa and equivalently in a radial plane decomposed rotational forces transferred to the "sine" - plane 8a shown by an arrow Fr. The rotational forces can be deduced from formula 2 : Fr = Fa. tan φ . According to the invention one achieves inter alia , by means of a particular design of the "sine" - plane according to the invention, the expansion stroke of the pistons 44,45 - reckoned angularly relative to the rotational arc of the drive shaft - becoming larger than the compression stroke of the pistons 44,45. In spite of the different speeds of movement of the pistons in opposite directions of movement, a relatively more uniform transfer of motive force to the drive shaft 11 can hereby be ensured and in addition a "more uniform", that is to say more vibration-free running of the engine. In Fig. 6 - 8 there is schematically shown the mode of operation pf a three cylinder engine 10, in which only the one piston 44 is shown of the two cooperating pistons 44,45, illustrated in a planar spread condition along an associated "sine" - curve 54', which consists of two mutually succeeding "sine" - planes, plus the associated main castor 53 of the associated one piston rod 48. In each of the Figures 6 - 8 there is schematically shown the associated one piston 44 in each of three cylinders 21 of the engine, an equivalent arrangement being employed for the piston 45 at the opposite end of the cylinders. For the sake of clarity the cylinder 21 and the opposite piston 45 have been omitted from Fig. 6 - 8, only the piston 44, its piston rod 48 and its main castor 53 being 21 shown. Axial movements of the piston 44 are illustrated by an arrow 57, which marks the compression stroke of the piston 44, and an arrow 58, which marks the expansion stroke of the piston 44. The "sine" - curve 54' is shown with a lower roll path 54, which has a double "sine" - plane-shaped contour and which generally guides the movement of the main castor 53 in an axial direction, in that it more or less constantly effects a downwardly directed force from the piston 44 via the main castor 53 towards the roll path 54 in the expansion stroke and an upwardly directed force from the roll path 54 via the main castor 53 towards the piston 44 in the compression stroke. The auxiliary castor 55 (not shown further in Fig. 6 - 8) is received with a sure fit relative to an upper roll path 54b, as is shown in Fig. 5a. For illustrative reasons the said roll path 56b is shown vertically above the main castor 53 in Fig. 6 - 8 , so as to indicate the maximum movement of the main castor in an axial direction relative to the roll path 54. In practice it will be the auxiliary castor 55 which controls the possibility for movement of the main castor 53 axially relative to its roll path 54, as is shown in Fig. 5a. The auxiliary castor 55 is normally not active, but will control movement of the piston 44 in an axial direction in the instances the main castor 53 has a tendency to raise itself from the cam-forming roll path 54. During operation lifting of the main castor 53 in an unintentional manner relative to the roll path 54 can hereby be avoided. The roll path 56 for the auxiliary castor 55 is, as shown in Fig. 5, normally arranged in the fixed fit spacing from the associated roll path 56a. In Fig. 6 - 8 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, relatively 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 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 are illustrated three pistons 44 and their respective main castor 53 shown in equivalent positions along an associated "sine" - curve in mutually different, succeeding positions. It is evident from the drawing that the relatively short first curve portions 60 entail that 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 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 is achieved with relatively greater speeds of movement in 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 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 which is relatively placed for disposition in the expansion stroke relative to the time which is reserved for the compression stroke. In a practical construction according to Fig. 6 - 8 there is chosen in 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 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 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. 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 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 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 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 in the combustion chamber Kl in the dead zones 4a and 4b, to a maximum, as shown in the maximum working chamber K in the dead points 0a and 0b (see Fig. 9 - 10 and 12 - 14) . According to the invention 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° in front of the dead point Oa of the curve 8a. The direction of rotation of the curves 8a and 8b, that is to say the direction of rotation of the drive shaft 11, is illustrated by the arrow E. In Fig. 9 and 10 there are schematically 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, shown spread in a schematically illustrating manner in one and the same plane. The five cylinders 21-1, 21-2, 21-3, 21-4 and 21-5 are shown in respective angular positions with a mutual angular space of 72°, that is to say in positions which are uniformly distributed around the axis of the rotary shaft 11. In Fig. 12 there is shown a first curve 8a, which covers an arc length of 180° from a position 0°/360° to a position 180°. A corresponding curve 8a (see Fig. 9) passes over a corresponding arc length of 180° from position 180° to position 360°. In other words two succeeding curves 8a for each 360° revolution of the drive shaft. The curve 8a shows in position 0°/360° a first dead point 0a. From position 0° to a position 38.4° there is shown a first transition portion la, which corresponds to a first part of a compression stroke and from position 38.4° to position 59.2° an obliquely (upwardly) extending rectilinear portion 2a, which corresponds to a main part of the compression stroke and from position 59.2° to a position 75° a second transition portion 3a, which corresponds to a finishing part of the compression stroke. Thereafter from the position 75° to a position 85° there is shown in connection with a second dead point a rectilinear dead portion 4a, which is shown passing over an arc length of 10°. From the position 80° to a position 95.8° there is shown a transition portion 5a, from the position 95.8° to a 11 position 160° an oblique downwardly extending, rectilinear portion 6a and from the position 160° to a position 180° a transition portion 7a. The three portions 5a, 6a, 7a together constitute an expansion portion. In position 180° is show anew the dead point Oa and thereafter the cam guide curve continues via a second corresponding curve 8a, from the position 180° to the position 360°, that is to say with two curves 8a which together extend over an arc length of 360°. In Fig. 13 there is shown an equivalent (mirror image) curve contour for the remaining curve 8b, shown with a dead point 0b and succeeding curve portion lb- 7b. There is shown the dead point 0b in a position 346°, - the curve portion lb between the positions 346° and the curve portion 2b between the positions 3° and 60°, the curve portion 3b between the positions 60° and 75°, - the curve portion 4b between the positions 75° and 80°, - the curve portion 5b between the positions 80° and 101.5°, - the curve portion 6b between the positions 101.5° and 146° and - the curve portion 7b between the positions 146° and 166°, that is to say with the dead point 0b shown anew in the position 166°. The cam guide continues with a corresponding curve 8b between the positions 166° and 346° (see Fig. 10) . The first curve 8a (Fig. 12) controls opening (position 160°/340°) and closing (position 205°/25°) of exhaust ports 25. The second curve 8b (Fig. 13) control opening (position 146°/326°) and closing (position 185°/5°) of scavenging ports 24. 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. Diagram 1 with reference to Fig. 9 and Fig. 12 - 13 Cylinder No. Angle Working Exhaust Scavenging Curve Position Position Ports Ports Zone 8a/8b 21-1 3°/183° compression closed open* la/lb 21-2 75°/255° compression closed closed 4a/4b 21-3 147°/327° expansion closed closed 6a/7b 21-4 219°/39° compression closed closed 2a/2b 21-5 291°/101° expansion closed closed 5b/6a * The scavenging ports 24 open in position 160°/340° and close in position 25°/205°, that is to say the scavenging ports 24 are held open over an arc length of 45°. 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) . 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) 11 after the exhaust ports 25 are closed. This means that the compression chamber over the last-mentioned arc length of 20° 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 21-4 237°/57° 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 λ2. 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 λ 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 changed relatively little. The spacing from the piston head 44a to the middle line 44' is changed from a minimum λ = 15 mm (in the dead portion 75° - 80°) to a 20 mm spacing (position 93° Fig. 13) " . Correspondingly the spacing from the piston head to the middle line 44' is changed from a minimum λ = 15 mm in the dead portion 75° - 80° to a 25 mm spacing in position 57° Fig. 13. Over said arc length of 36.6° the volume in the combustion chamber Kl is kept approximately constant between the pistons 44,45. Combined effects of two phase-displaced "sine" - planes From Fig. 14 the contours of the respective two curves 8a, 8b, which are shown schematically in mirror image relative to each other will be evident. Curve 8b is shown real with a full line, while curve 8b is shown with a broken line, in mirror image about a middle axis between the pistons 44,45. The curve 8c shows a theoretical midmost curve between the curves 8a, 8b. It will be evident that the midmost curve 8c has a contour which lies more closely up to a sine curve contour than the contours of the curves 8a, 8b individually. Consequently, even if one gets a relatively unsymmetrical contour in the curves 8a, 8b mutually, a relatively symmetrical contour of the midmost curve 8c can be achieved. Fuel is injected: At the close of the compression phase in curve zone 3a and 3b the fuel is injected in a jet with a flow into the rotating scavenging air current and is mixed/atomised effectively in the rotating scavenging air current . Ignition starter: Immediately after the injection of fuel that is to say at the close of the compression phase electronically controlled ignition is initiated in curve zone 3a and 3b. Provision being made for effective rotation of the gas mixture of scavenging air and fuel in a fuel cloud past the ignition arrangement. According to the present invention one can aim with advantage at an ignition delay of 7 - 10% relative to the conventional ignition angle. Combustion phase In the illustrated embodiment the combustion starts immediately after ignition and is accomplished mainly over a limited region in which the pistons roughly occupy a maximum pushed in position, that is to say at the close of the curve zone 3a, 3b, that is to say in a region where the 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 in the inner dead portion 4a and 4b, that is to say over an arc length of 10° and 5° respectively. However the combustion continues as required to a greater or smaller degree in the following transition portion 5a, 5b and in the main expansion portion 6a, 6b, depending upon the speed of rotation of the rotary shaft. As a consequence of the rotating fuel cloud in the combustion chamber Kl in the dead portion 4a, 4b and in that one can keep the flame front relatively short in the disc-shaped combustion chamber Kl , there can be ensured in all instances fuel ignition for a main bulk of the fuel cloud in the combustion chamber Kl , that is to say within said dead portion 4a, 4b. In practice the combustion chamber can be allowed to be expanded to the portion 5a, 5b just outside the dead portion 4a, 4b with largely corresponding advantages in a defined volume of the working chamber K. Speed of combustion The speed of combustion is as known of an order of magnitude of 20 - 25 meters per second. By the application of a double set of fuel nozzles and a corresponding double set of ignition arrangements distributed over each quarter of the peripheral angle of the working chamber (see Fig. 4b) the combustion area can be effectively covered over the whole of the disc-shaped combustion chamber Kl . In 1 practice especially favourable combustion can thereby be achieved with relatively short flame lengths. Optimal combustion temperature: As a result of the concentrated ignition/combustion 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 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 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 - 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 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 - 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 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 expansion stroke (in the region 6a, 6b) and at least in the beginning of this region, as a consequence of possible after burn of fuel in this region in spite of the volumetric expansion which occurs gradually in the chamber K as the expansion stroke proceeds forward through this. Expansion Phase According to the illustrated embodiment the compression phase takes place relative to the curves 8a, 8b under angles of inclination of between about 25° and about 36° in the respective two curves 8a and 8b, that is to say with a mean angle (see Fig. 14) of about 30°. If desired the angles of inclination (and the mean angle) can for instance be increased to about 45° or more as required. The expansion phase takes place correspondingly in the illustrated embodiment at between about 22° and 27° in the two curves 8a and 8b, that is to say while at a mean angle (see Fig. 14) of about 24°. As a result of the relatively steep (mean) curve contour of 30° in the compression phase and the relatively gentler contour 24° in the expansion phase, there is achieved a particularly favourable increase of the durability in time of the expansion stroke relative to the durability of the compression stroke. According to the invention one can by means of said unsymmetrical relationship between the speed of movement in the compression stroke and the speed of movement in the expansion stroke, displace the start of the combustion process in the compression phase closer up to the inner dead point and thereby time-displace a larger part of the combustion process to the beginning of the expansion phase, without this having negative consequences for the combustion. Consequently there can be achieved a better control and a more effective utilisation of the motive force of the fuel combustion in the expansion phase than hitherto. Inter alia there can be displaced an otherwise possibly occurring, uncontrolled combustion from the compression phase over the dead point to the expansion 11 phase and thereby convert such " pressure points", which involve uncontrolled combustion in the compression phase, to useful work in the expansion phase. 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. 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 25 (see Fig. 2) followed by the injection of scavenging air via the obliquely disposed 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 in the course of the working cycle, that is to say during the injection, 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 injection via the nozzle 36 and subsequent 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 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. 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 nozzle 37a, which is disposed angularly displaced relative to the first fuel nozzle 37, and by the application of an extra ignition arrangement 39a, which is disposed angularly displaced relative to the first ignition arrangement 39. When the exhaust ports 25 open again, on the termination of the working cycle, the exhaust gas is exhausted with a high speed of movement, that is to say with a high rotational speed, during exhaustion of exhaust gas via the said obliquely disposed exhaust ports. Further the rotational effect for the exhaust gases is maintained immediately the obliquely disposed scavenging ports 24 open, so that the residues of the exhaust gases are scavenged with a rotational effect outwardly from he working chamber K at the close of the expansion phase and the beginning of the compression phase. Thereafter the rotational effect is maintained, after closing of the exhaust ports, the scavenging ports being continued to be held open over a significant arc length. Regulation of the compression ratio of the engine during operation According to the invention it is possible to regulate the volume between pistons 44,45 of the cylinder 21 by regulating the mutual spacing between the pistons 44,45. It is hereby possible to directly regulate the compression ratio in the cylinder 21 as required, for instance during operation of the engine by means of a simple regulation technique adapted according to the "sine" - concept. It is especially interesting according to the invention to change the compression ratio in connection with starting up the 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 change the compression ratio during operation for various other reasons . A constructional solution for such a regulation according to the invention is based on pressure oil - controlled regulating technique. Alternatively there can be employed for instance electron-controlled regulating technique, which 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 shown for the cam guide device 12b. It is apparent according to the invention that it is possible to regulate the position of both pistons 44,45 in the associated cylinder via their respective cam guide arrangement with their respective separate possibility of regulation, in a mutually independent manner. It is also apparent that the regulation of the position of the pistons in the cylinder can be effected synchronously for the two pistons 44,45 or individually as required. In Fig. 15 and 16 there is shown schematically an alternative solution of certain details in a cam guide device, as it is referred to herein by the reference numeral 112a, and of an associated piston rod, as shown by the reference numeral 148 as well as a pair of pressure spheres, as shown by the reference numerals 153 and 155. The cam guide device 112a: In the construction according to Fig. 1 the cam guide device 12a is shown having a relatively space-demanding design with associated casters 53 and 55 arranged at the side of each other in the radial direction of the cam guide device 12a, that is to say with the one caster 53 arranged radially outside the remaining caster 55 and with the associated "sine" - grooves 54,55c illustrated correspondingly radially separated on each of their radial projections In the alternative construction according to Fig. 15 and 16 the cam guide device 112a is shown with associated pressure spheres 153, 155 arranged in succession in the axial direction of the cam guide device 112a, that is to say with a sphere on each respective side of an indivi- Oi d PJ i- 1 - Ω 0 3 3 0 d TJ H{ 0 CJ. Φ Ω rt μ- 0 d μ- d rf 01 rt Hi PJ rt Φ Oi μ- d rt tr Φ Hi 0 Hi 3 0 Hi PJ d 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 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 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 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. 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 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 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 are obtained hereby pressure spheres of low weight and small volume, and in addition there is achieved a certain 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 148a of the piston rod 148.

Claims: Patent Claims 1. Arrangement in a combustion engine (10) having internal combustion, comprising a number of engine cylinders (21) , which are arranged in an annular series around a common middle drive shaft (11) and which have cylinder axes running parallel to the drive shaft, each cylinder including 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, while each piston (44,45) is equipped with its respective axially movable piston rod (48,49), the free outer end of which forms via a support roller (53) support against its respective curve-shaped, that is to say "sine" - curve shaped, cam guide device (12a, 12b), which is arranged at each of opposite ends of the cylinder (21) and which controls movements of the piston relative to the associated cylinder, characterised in that at least the one (44) of the two pistons (44,45) in each cylinder is regulatably adjustable axially in the cylinder for regulating the relative spacing between the pistons, especially for regulating the compression ratio i) in the common working chamber (K) between the pistons. 2. Arrangement in accordance with claim 1, characterised in that the position of the piston (44,45) in the cylinder (21) is adapted to be determined via the associated cam guide device (12a, 12b) of the piston by means of a separately regulatable control arrangement (13b) . 3. Arrangement in accordance with claim 2, characterised in that the said one cam guide device (12b) is axially displaceable along the drive shaft (11) in a sliding abutment on this, and is adjustable within a limited length of the drive shaft (11) by means of said separately regulatable control arrangement (13b) . 4. Arrangement in accordance with claim 3 , characterised in that ' the control arrangement (13b) is regulatable by means of pressure oil . 5. Arrangement in accordance with claim 4 , characterised in that the control arrangement comprises an annular pressure oil chamber (13b) , which is defined between the drive shaft (11) and the cam guide device (12b) , and a piston- forming compression simulator (12b'), which projects from the cam guide device (12b) radially inwardly into the pressure oil chamber (13a) and partitions this into two part-chambers, that is to say one on each side of the compression simulator, the part-chambers communicating with their respective, mutually adapted pressure oil circuits. 6. Arrangement in accordance with one of the claims 1 - 5, characterised in that the cam guide device (12b) is fast connected for rotation with the drive shaft (11) , the compression simulator (12b') being passed through parallel to the axis of the drive shaft (11) by a set of driving bolts (12'), which allow a certain axial movement of the compression simulator (12b') relative to the drive shaft (11) , while the driving bolts (12') are connected at their respective opposite ends to the drive shaft (11) and connected to a carrying member (13) fastened to the drive shaft (11) . 7. Arrangement in accordance with claim 6, characterised in that the drive shaft (11) is axially extended at its outer end with a radially graduated end portion, which is rigidly connected to the carrying member (13) in the form of a cup-shaped end part, the pressure oil chamber (13b) being localised between the drive shaft (11) and the cup-shaped carrying member (13) . 8. Arrangement in accordance with claim 6 or 7, characterised in that an oil guide means (14) , which projects axially through an axial bore in the cup-shaped carrier member (13) and further inwardly into an axial bore in the drive shaft (11) aligned with that is provided with a pair of internal, axially extending pressure oil ducts (14a, 14b), which empty radially outwards into their respective associated pressure oil rings (14a', 14b') which communi- cate with a pressure oil duct (llf, llg) to respective part-chambers of the pressure oil chamber (13b) . 9. Arrangement in accordance with one of the claims 1 - 8, characterised in that one piston (44) of the cylinder (21) , which is in question to regulate the position of in the associated cylinder, constitutes a piston which controls opening and closing of exhaust ports (24) of the cylinder.

Inventors: HENRIKSEN LEIF DAG, HENRIKSEN, LEIF, DAG
Applicants: HENRIKSEN LEIF DAG, HENRIKSEN, LEIF, DAG
Application year: 1998
Main classification: F02B75
IPC codes: F01B3, F01B9, F02B75, F02D15