EP2986837B1 - Piston machine and method for the operation thereof - Google Patents

Description

The invention relates to a reciprocating engine and to a method for its operation for the conversion of heat into work or for heating or cooling by the expenditure of labor, with at least one chamber arrangement having at least two, connected by at least one connecting channel chambers, wherein at least two of the chambers from each other are substantially thermally insulated and have different capacities and working temperatures, and arranged in the respective chambers movable, for a working fluid impermeable piston for changing a limited by the chamber and the piston part-working volume, wherein at least one of the chambers heat transfer surfaces to increase their surface area wherein the pistons or associated elements are connected to actuating means for determining movement profiles for each of the pistons, wherein the actuating means for determining at least two different movement profile en the piston of the chamber assembly are formed.

As heat transfer surfaces surface areas of the chamber surface are to be understood, which are heated or cooled by targeted technical measures to absorb or release heat for thermodynamic purposes. In addition, if the heat transfer surfaces even a significant increase in the inner surface of the chamber relative to the original shape of the chamber, that is relative to the chamber underlying simple geometric body, such as a cylinder with a flat or dome-shaped base and / or top surface, cause, or, in Doubts, when heat transfer surfaces are present in the chamber and the inner chamber surface of the chamber to the largest operationally reached partial working volume expanded the surface of a comparably equal in volume comparative cylinder with circular, flat ground and top surface and with the ratio of diameter to height equal to 1 micron exceeds 1.5 times, the chamber has heat transfer surfaces to increase its surface area.

The most common and well-known reciprocating engines for converting heat into work are automotive engines, such as the diesel engine or the gasoline engine. The underlying of these machines thermodynamic cycle is the diesel process or the Otto process or in general the Seiliger process. The preferred one Comparative process of the present invention, ie that thermodynamic cycle, which the present invention preferably approximates, in contrast, the known Carnot process. This describes the physical maximum of the conversion of heat into mechanical energy for given heat sources and sinks. Consequently, both the above-mentioned cycle processes, as well as, for example, the machines modeled in connection with turbomachines Joul, Ericsen or Clausius-Rankine processes have an inherently suboptimal efficiency. An exception to this are Stirling machines whose comparison process is the Stirling process, since theoretically the same efficiency could be achieved by using a regenerator assumed to be perfectly functioning as in the Carnot process. However, this possibility has proven to be disadvantageous in many cases because the regenerator during a Prozessarbeitsspiels or process run or cycle of a cycle, which or which is the unique sequence of the cyclic characterizing thermodynamic state changes, including any intermediate clocks or steps, never the stored heat for Whole can give it back and caused by him even large dead or dead spaces.

The DE 27 36 472 A1 shows a valveless piston machine with two cylinders and arranged therein pistons whose cranks are offset so that the movement of the piston has a fixed phase shift of 90 °. To improve the heat transfer in the cylinders, one of which has a heating chamber and the other a cold space on the working medium (preferably helium) or vice versa, the piston and the cylinders are provided with complementary, projecting into the working space surfaces. The cylinders are connected by a heat exchanger extending arcuately between the cylinders, which has areas for heat storage and thus is a typical for Stirling engines regenerator.

The from the DE 103 19 806 B4 known heat engine also works on the Stirling principle. An expansion cylinder with a heater forms an expansion space and a compression cylinder with a cooler forms a compression space. The two work spaces have a plurality of parallel, conical tubes, in which engage respective piston pins of the respective associated pistons and fill them. The work spaces are connected via separate overflow channels, which are used as heat exchanger surfaces and provided with check valves, and the movement of the two pistons is also offset by 90 crank angle degrees.

A disadvantage of the in the DE 27 36 472 A1 and DE 103 19 806 B4 described machines is that each of the two pistons follow the same sequence of movements, namely essentially a sinusoidal movement, which is offset in time only by a phase shift of 90 ° (corresponding to a quarter-cycle) between the pistons. However, such a process can roughly approximate an ideal Stirling process so that only a reduced degree of efficiency is achieved on its own.

Furthermore, the shows JP H07 19109 A a sterling machine with three chambers, the pistons being guided on a common eccentric shaft.

Pistons with different motion profiles have already been shown in connection with fundamentally different Stirling engines, but always at least one piston is a regenerator, which can never be impermeable to a working medium, since the working medium can either pass through or be able to flow past , Examples of such machines can be found in the DE 195 28 103 A1 . DE 198 54 839 C1 and CH 701 391 B1 , Due to the completely different structure and the different operation, however, heat transfer surfaces are not provided in the chambers in any of these machines. Therefore, and also because all of the machines shown have a considerable dead space due to the regenerators alone, none of these machines is suitable for recreating the Carnot process.

The US 5,095,700 A. shows a heat engine for simulating either the Stirling process or the Ericsson process, wherein a regenerator is arranged in a connection channel between two chambers.

Accordingly, it is an object of the present invention to propose a reciprocating piston engine which operates according to an approximately ideal Carnot process by reducing dead spaces as much as possible, achieving optimal heat exchange between the chamber walls and the working medium in certain chambers, and at the same time the ideal state changes the Carnot process adapted movements of the piston allows. In particular, an improved approximation of a process with isentropic state changes is to be achieved.

Such an improvement is achieved in a piston engine of the type mentioned in that the chamber assembly comprises three chambers, wherein a middle of the three chambers is connected through the at least one connecting channel with the two chambers with different capacities and working temperatures and a larger capacity than that of has two chambers with a relatively high operating temperature, the average chamber due to their shape, in the arithmetic mean a greater distance between an arbitrarily small volume particles of their volume extended to a reference volume working volume and the partial working volume limiting inner chamber surface than at least one the at least two chambers connected by at least one connecting channel, wherein the reference volume is the maximum partial operation operatively achieved by the two compared chambers Of course, the internal chamber surface defining the partial working volume also includes the possible heat transfer surfaces for enlarging the surface of the chamber and the surface areas of the piston disposed in the chamber and defining the distance as the length of the shortest connecting line. In order to be able to perform as faithfully as possible isentropic state changes in two of the chambers with the heat transfer surfaces and in spite of the conditions limited in the chambers with the heat transfer surfaces for an adiabatic change in state of the working medium, it is advantageous that the chamber arrangement comprises three chambers, wherein the middle chamber through the at least one connecting channel is connected to the other two chambers. In the case of three and more than three chambers, the term "middle chamber" is to be understood as meaning those chambers in which mainly approximately isentropic state changes take place. The other chambers, ie those chambers in which mainly approximately isothermal state changes take place, are connected to the central chamber (s). Since the middle chamber has a larger capacity than one of the chambers with a relatively high working temperature, a comparatively even faster volume change can be achieved, for example due to mechanical limitations, given piston speed. In addition, it can that in a isentropic state change of the working medium required maximum of the working volume are made available suitable.

With which actuating means the motion profiles, ie the temporal sequences of the piston movements, are fixed, is of less importance. The term movement profile is intended to express in particular that different movement specifications are involved with different movement profiles in terms of their temporal characteristics, for example by achieving a fundamentally different chronological sequence of the piston movements. For example, only temporally shifted or staggered or different in amplitude amplitude motion profiles are not different in the meaning of the invention, ie different movements are not synonymous with different motion profiles. In addition, it is of central importance that - as already mentioned - the pistons assigned to the said actuating means are impermeable to the working medium, that is, they can not pass the working medium through them and seal tightly with the chamber walls, since this is the only way of avoiding efficiency-reducing dead spaces as far as possible can be achieved, which makes the different motion profiles according to the invention for the solution of the task only make sense. In contrast, machines with permeable or non-tight-fitting pistons pursue a completely different goal, namely the implementation of the Stirling process, the respective pistons usually working as regenerators. The present piston engine does without a regenerator or is constructed regeneratorless. In particular, the connecting channels have a smooth surface and a small volume compared to the expanded chambers, but their cross-sections are preferably still large enough to achieve an approximately resistance-free flowability. Furthermore, the connecting channels have a small internal volume which can be easily overflowed by the working medium with respect to the size compared with the expanded chambers, in particular with respect to a chamber with heat transfer surfaces to increase its surface area. The connecting channels thus have a free flow and a relation to the working medium substantially thermally neutral behavior. Both the pistons and the connection channels between the chambers are free of a regenerated by the working medium regenerator, which otherwise inevitably resulting dead space can be avoided.

Accordingly, in a method of the type mentioned above for operating such a piston engine, the stated object is achieved in that in the course of a running in the chamber assembly run of the approximate Carnot process at least one, preferably each, the piston involved in the passage in terms of passage at least Once during a dead phase is substantially still, wherein a limited by the piston and its associated chamber partial working volume during the dead phase is substantially zero. The dead phase in this case denotes a temporal portion of a certain (finite) duration and not just a point in time, such as the reversal point or dead center typical in pistons.

The term partial working volume refers above and below to the volume defined at a particular time in a chamber, ie by the chamber and the piston assigned to it. The term working volume refers in each case to the sum of the volumes of those partial working volumes and those volumes of the connecting channels, which are all interrelated, ie are not sealed from one another, wherein the working medium contained in the working volume and the working medium contained in the sum of the volumes are identical. This also means that the working volume at least a certain part-working volume and vice versa the part-working volume is assigned a specific volume of work. In other words, and taking into account the relatively small volumes of the connection channels, it can also be said that the working volume is essentially the sum of the mutually associated partial working volumes assigned to it. In addition, it follows that a partial working volume of a chamber is always smaller (theoretically at most equal if there were precisely a partial working volume associated with the working volume and the related volumes of the connecting channels were zero) than the working volume assigned to it. So it is just possible for the purpose of increasing efficiency, that in a chamber arrangement from four chambers two or even more chambers more separate working volumes are in the chamber assembly, the pistons of the chamber assembly can control different working media during different periods of time, in which context different working media does not necessarily mean different types of working media, but it means in that the different working media are in different volumes of work. Accordingly, a plurality of cycle processes, each of which in this case has its own working medium, can be executed in parallel in the chamber arrangement. If these circular processes are similar in their nature, for example two approximate Carnot processes, then one can also say that the approximate Carnot process is performed twice in the chamber arrangement. However, the circular processes performed in parallel in the chamber arrangement may also be different in their nature, for example an approximate Carnot and an approximate Stirling process.
During operation of the piston engine according to the invention, the state points of a cycle process carried out with it can change from one cycle to another, without necessarily having to change the type of cycle process. This means that one cycle of a cycle, for example in the pV diagram, may look different than another cycle of the same cycle. In particular, in actuating means for generating variable motion profiles, it is also possible that during operation of the piston engine according to the invention changes the nature of a cycle performed with her, for example, an initially executed in the chamber arrangement approximate Stirling process later transferred into an approximate Carnot process become.

Furthermore, it may be that during a cycle of a cycle, or during the duration of this cycle, not all pistons of the chamber arrangement with the working medium involved in the passage, which may be in the chamber arrangement with other, independent working media, come into contact. Even if the chamber arrangement has only a single working medium, or in the chamber arrangement with only a single working fluid a cyclic process is performed, not necessarily all pistons of the chamber assembly at one and involved in the same cycle of the cycle because, for example, some pistons of the chamber assembly may be stationary all the time during the one pass to receive only heat from its heat source, thus only one set of pistons involved in that one pass may exist in the chamber assembly.

In any case, above and below, each run of a cyclic process is considered to be unique, even if two cycles of a cycle appear identical, for example, to their p-V diagrams.

When at least two of the chambers have the heat transfer surfaces to increase their surface area, efficient and rapid heat exchange with the chamber environment can advantageously be achieved both in heat absorption and in heat release.

In order to achieve the most ideal state change possible in one of the other chambers, in particular with regard to the isotropic state change aimed at during the Carnot process, it is advantageous if at least one of the motion profiles defined by the actuating means has at least one dead phase during which one of the corresponding with the Actuator connected piston is substantially stationary.

Furthermore, it is favorable for such motion profiles to avoid dead spaces when a part of the working volume limited by the piston located in the dead phase of its movement profile and the chamber assigned to it is substantially zero. The temporarily stationary piston not only closes - as stated above - tightly against the chamber assigned to it, but also completely fills it, so that any working medium is removed from the chamber. Of course, with regard to one of the other pistons, whose movement profile likewise has a dead phase, a partial working volume deviating from zero during the dead phase can be provided.

To the Carnot's own asymmetry in terms of the Time sequence of the working volume or the partial working volumes and the best possible practical feasibility of state changes, such as necessary for isentropic state changes relatively high speed of expansion and compression or necessary for isothermal state changes relatively slow speed of expansion and compression or even the relative short period of time for the most adiabatic chamber change of the working medium to take into account, it has been found to be advantageous if at least one of the motion profiles different time intervals between a reversal point and the following dead phase on the one hand and between the dead phase and the temporal following reversal point on the other hand, in particular is directional. The different time intervals can be understood, for example, in the case of the isotropic expansion compared to the isentropic compression, which is illustrated in the following, with the result that at the same piston speed and the same piston cross-sectional area of the considered piston, the isentropic expansion lasts longer as the isentropic compression. Furthermore, in the case of the isothermal state changes, in order to be able to carry them out as faithfully as possible, these are advantageous compared to the change of the working medium into the other chamber - this intermediate cycle takes place expediently faster, because it saves time and rather adiabatically - runs slowly.

When the actuation means of the chamber arrangement or the motion profiles defined by them are coordinated with one another such that the observation is directed to a single working volume, which is essentially the sum of the associated, associated partial working volumes, at least one of the chambers during operation and at most two of the chambers has or have a substantially different from zero part-working volume, on the one hand advantageously a clear spatial separation of the state changes can be achieved and on the other hand made the change of the working medium from one to the other chamber meaningful, while meanwhile depending on Number of existing chambers of the chamber arrangement it is favorable, a change in state of the working medium perform - especially in 2 chambers - or perform no change in state - especially in more than 2 chambers. Thus, the working volume, ie also the working medium, is always subjected to a state change or a chamber change in the chamber (s) provided for this purpose, which increases the efficiency of the piston engine. This applies regardless of whether more than one working medium is conveyed in a chamber arrangement with four or more chambers. In these cases too, at least one of the chambers and at most two of the chambers have, during operation, a proportion of one and the same working volume which is substantially different from zero. Possibly enclosed by other chambers of the chamber assembly and by the relevant working volume at any time during a process run tightly separated (partial) working volumes are therefore not excluded. The tuning of the actuating means can be done by a coordination means, for example a common axis or a common or communicating programmable controller (s).

To avoid efficiency-reducing losses during transport of the working medium between the chambers, it is advantageous if the at least one connecting channel is valveless. Thus, the opposite of a valve to the working fluid resistance, which is among other things, the necessary force to open the valve, avoided. In addition, valveless connection channels have the advantage of simpler construction and greater reliability.

A known in other machines way to achieve the required heat transfer surfaces is that the heat transfer surfaces of one of the chambers of the Innenbewandung the corresponding chamber are formed and disposed in the corresponding chamber piston has a complementary to the heat transfer surfaces of the corresponding chamber surface, which preferably is also designed to transfer heat. With such a chamber geometry, a relatively large piston cross-section can be simulated with regard to the heat transfer in a relatively small space, with the same heat transfer, the piston movement based on the simulated piston cross-section, ie the actual Piston surface, apparently slowed down. As a result, a favorable surface-to-volume ratio is achieved, which favors a rapid heat exchange or a rapid compensation of any temperature differences in the working medium.

In addition, one can accomplish that the heat transfer surfaces of one of the chambers are formed with a garland-like heat transfer body, which is arranged in the corresponding chamber or between the corresponding chamber and its associated piston. Such a garland-like heat transfer body is stretched or compressed during a piston movement and can achieve any surface enlargement depending on the number of layers or turns. With suitable dimensions, i. if the cross-section or base area of the fully compressed ("collapsed") heat transfer body substantially corresponds to the piston cross-section, the partial working volume of the chamber in question can advantageously be reduced to zero, in particular if within the corresponding chamber or on its associated piston a more complementary to the merged heat transfer body body is present. Another advantage of such a heat transfer body is the simple and good heat exchange with the chamber during the dead phase, since the necessary for the transmission distance is significantly shortened at superimposed layers. Of course, it is within the meaning of the invention, also several heat transfer surfaces in this manner, i. with garland-like heat transfer bodies, and it is also possible for a plurality of such heat transfer bodies to form the heat transfer surfaces or be arranged in a single chamber.

Another way to constructively compensate for the asymmetry of the Carnot process explained above is that of the two chambers with different capacities and working temperatures, one chamber with a relatively low working temperature has a larger capacity than the other chamber with a relatively high working temperature. In particular, the capacity can be adjusted by different chamber cross sections. Moreover, it is advantageous if the pistons in their associated chamber have an approximately equal lift capacity. This results in a good use of space, since typically at least one outer dimension of the piston engine according to the invention anyway depends on the chamber with the largest lifting capacity. Furthermore, this promotes an advantageous identical parts concept of the components used.

Particularly flexible and precisely configurable motion profiles can be achieved if at least one of the actuating means has a cam element with which the piston associated with the actuating means or elements connected to the piston is or are connected via a rolling element. In this case, the curve element, which may be formed for example by a cam, emulate exactly the desired movement through its arbitrarily producible form and optionally simultaneously act as a flywheel.

To avoid any losses in reversing the direction of movement of the piston, i. between pulling and pushing movement, to avoid the rolling element can consist of at least two profile rollers, the at least two profile rollers do not change their directions of rotation due to their arrangement during a running in the chamber assembly (8) run a circular process with the same direction of rotation of their associated cam element. In this case, in particular, one of the profile rollers can be arranged radially inwardly relative to the cam element and the other profile roller opposite to it radially, so that during thrust movements a force transmission via the radially inner profile roller and during tensile movements a force transmission via the radially outer profile roller.

In order to keep unwanted because losses causing forces or torques as low as possible, it has proven to be favorable when a determined in the stroke direction center distance between a guide roller of the rolling elements and one of the profile rollers of the same rolling element is small compared to a Lifting direction determined distance between the axis of rotation of the profile roller and the rolling element associated piston, preferably about zero, so that a possible frictionless Movement of the rolling element associated piston is achieved in the chamber. As a result, particularly high friction-causing lateral forces on the piston can be avoided, which would otherwise worsen the efficiency of the piston engine.

A mechanically even less limited power transmission from or to a piston can be achieved if at least one of the actuating means has a motor-generator unit and the or the actuating means associated (n) piston or associated elements with the rotor of Motor-generator unit is connected or are. The motor-generator unit can of course also consist of a motor and a separate generator whose rotor are mechanically coupled. Likewise, a possible servo amplifier and / or a programmable controller may belong to the motor-generator unit.

The movement profiles realized with the aid of such actuating means can even be adaptable during operation if at least one of the actuating means is suitable, in particular freely programmable, for generating variable movement profiles. As a result, consideration can be given in particular to a different amount of available heat or work and the other changing boundary conditions for the operation of the piston engine according to the invention.

Since the forces exerted by or on the pistons naturally also vary in magnitude depending on the chamber, it is favorable if at least one of the actuating means and its associated piston a transmission gear, in particular a pantographartiges coupling gear, or a ball screw is interposed. For example, this also favorable movement speeds of the rotor of electromagnetic actuation means can be achieved without having to do without the optimum for the state change process speed.

In order in the chamber arrangement, in particular with regard to the amount of heat transferred during a state change between Chamber and working medium, different types of state changes, especially at different temperatures taking approximately isothermal state changes on the one hand and the approximate isentropic state change on the other hand to run the working medium, it is advantageous if the middle chamber due to their shape, in the arithmetic mean one at least 1, 5 times greater distance between an arbitrarily small assumed volume particles of their extended to the reference volume partial working volume and the partial working volume limiting inner chamber surface as at least one of the at least two, connected by at least one connecting channel chambers.

In order to avoid a falsification of the isotropic state changes accompanying a heat exchange and a consequent reduction in the efficiency of the reciprocating engine, the middle chamber (s) is favorably free of heat transfer surfaces for enlarging their surface and / or thermally at least opposite one of the other chambers, in particular at least with respect to the chamber with a relatively high working temperature isolated. It is therefore beneficial if the middle chamber (s) each have a smaller inner surface than a chamber having heat transfer surfaces to increase its surface area, particularly that chamber having a relatively lower working temperature.

In order to control the amounts of heat which are exchanged during the state changes between the chambers and the working medium carried out in the chambers of the piston engine according to the invention and which are decisive for the different types of state changes, advantageously at least one of the at least two, by at least one connecting channel connected chambers with the working medium, preferably during an approximately isothermal state change, to exchange a relatively large amount of heat, have a large inner surface or it is favorable if as much of the working medium is very close to its inner chamber surface, which advantageously be achieved thereby can, that opposite surface areas of the inner chamber surface have a small distance. As a further advantage for the replacement of a relatively large amount of heat, for example, the piston cross section can be relatively large and the piston stroke are chosen to be relatively small - or vice versa, but it could also have areas of the inner chamber surface a deep jagged shape or it could be in the chamber a stretch or . compressible garland-like heat transfer body be arranged with heat transfer surfaces.

The chamber, preferably the middle chamber, with which the working medium, preferably during an approximately isentropic state change, should exchange a relatively small amount of heat may preferably have a small inner surface or it is favorable for this chamber, if as much as possible from the working medium remote from its interior chamber surface, which may preferably be thermally isolated from the external environment, which may be achieved, for example, by widely spaced opposed surface areas of the interior chamber surface. A just mentioned chamber may advantageously have a piston diameter which is the same size as its piston stroke. Furthermore, it is favorable if the interior of the chamber is designed predominantly with a smooth surface, and it would additionally be favorable if the inner chamber surface had only a few or no protrusions or indentations.

To be able to perform in the chamber with the heat transfer surfaces to increase their (inner) surface in particular an approximate isothermal state change of the working medium and to achieve good heat exchange of the chamber with the working medium by their inner surface is made as large as possible and / or the working medium as possible brought close to its inner surface, it is advantageous if the profile of the heat transfer surfaces produced by a cut to increase the (inner) surface of the chamber is formed several times jagged.

Due to the different tasks relating to heat exchange with the working fluid and to avoid a heat flow between the chambers, it is advantageous if one of the chambers with the heat transfer surfaces made of a material with relatively high heat capacity and good thermal conductivity, in particular copper or aluminum or their alloys is and the middle chamber is made of a thermally poorly conductive material, in particular ceramic or glass ceramic.

If one of the chamber arrangements has a gas with a high specific gas constant, in particular helium, as working medium, the flow losses during the transport of the gas between the cylinders can be reduced since the moved mass can remain small. Furthermore, the installation space of the chamber arrangement can thereby be reduced with the same energy converted by the chamber arrangement. Of course, it is particularly advantageous if several or even all chamber arrangements have a corresponding working medium, but different working media can also be used. On the other hand, the use of air as a working medium is associated with advantages; For example, depending on the working pressure, the tightness of the chamber arrangement is less problematic, since leakage of air into the environment is generally not critical.

The forces to be transmitted between one of the pistons and its associated actuating means can further be optimized and the associated losses reduced if at least one of the pistons is connected to a spring element, in particular a magnetic, mechanical or gaseous spring element, to support the actuating means associated with the piston is. In particular, this can be any losses caused by the actuating means, in particular caused by electromagnetically operating actuation means while they predict dead phases, can be reduced.

The forces transmitted to the necessary linear movements of the pistons, for example, to a substrate or to a bearing of the piston engine naturally lead, for example due to unavoidable damping etc., to losses, which can be reduced if at least one further, substantially identical to the chamber arrangement chamber arrangement is provided with a piston, wherein cancel the mass inertia effects of the pistons together with associated elements of all chamber arrangements substantially. The essential mass inertia effects are in particular the inertia forces of the pistons, and those of the elements connected to the piston, wherein also moments of inertia, for example, the actuating means are included.

It is also advantageous if at least two different chamber arrangements belonging pistons are connected to a common actuating means. Preferably, the pistons connected to a common actuating means are related, i. the volume changes achieved by them belong to similar state changes in the various chamber arrangements. The common actuating means may for example cause a symmetrical movement of the pistons of different chamber arrangements, the synchronization of the movements being guaranteed in a natural way by the unit of the actuating means.

In the above-mentioned method for operating a piston engine of the type described so far, it is particularly favorable if a working volume of the chamber arrangement, which is essentially the sum of the associated, associated partial working volumes, at all times substantially to its associated part Work volumes of one or two of the chambers is distributed. In such a distribution, i. If, at any given time or at any time during a cycle, any third or further chambers of the same chamber arrangement have a substantially zero working volume, a nearly ideal and thus almost unaltered change of state of the working medium or a change in chamber of the working medium be achieved, which is desirable to achieve the optimum efficiency.

In order to achieve a homogeneous temperature in the entire volume of the working medium, it is favorable if the duration of the dead phase of one of the pistons or in the chamber associated with the piston is almost equal to or greater than the duration of time with this dead phase at least partially with respect to the passage overlapping pass associated with the approximately isothermal state change in one of the other chambers involved in the pass. In such a process, the isothermal state change preferably takes place entirely in a single chamber of the chamber arrangement.

If within the chamber arrangement with regard to the passage Each of the Totphasen involved it at least 15%, in particular at least 25%, the time of passage, a particularly good and uniform temperature distribution in the relevant chamber or its associated piston can adjust during one of the dead phases, whereby, for example, in the chamber following their dead phase following state change of the working medium can follow the desired desired state change particularly well.

It is advantageous if a change of state of the working medium can be carried out undisturbed in one of the other chambers participating in the passage of a cycle process carried out in the chamber arrangement and further corresponds to a clear allocation of a chamber to a few, immediately consecutive state changes, if each of the on the Pass involved piston in one of their associated chambers with direct connection to exactly one of the other participating chambers with respect to the passage exactly one of the passage associated dead phase. For the same reasons, it is advantageous if each of the pistons involved in the pass has exactly one dead phase associated with the pass in one of its associated chambers having unidirectionally flowed through the unidirectionally flowed direct connection to exactly two other of the chambers involved therein.

Conversely, a plurality of similar state changes, especially if they do not require heat exchange, also be performed in the same chamber, so that each of the pistons involved in the passage in one of their associated chambers with bidirectional flow through the participating working medium direct connection to two more of the involved chambers with respect to the passage has two dead phases associated with the passage.

A particularly good approximation of the comparison process can be achieved if the total duration of all the dead phases associated with the passage of the piston, which participates in at least one of the approximately isentropic state changes involved in the passage, is longer than the dead phase of the piston at one of the approximately isothermal state changes involved in the pass participates. Accordingly, it is favorable if, in total, the two approximately isotropic state changes of the pass are carried out more rapidly, in particular at least twice, faster than the sum of the two approximately isothermal state changes assigned to the pass. Thereby, enough time can be given to the heat exchange during the isothermal state change, while counteracting a change in entropy in the short time during the faster isentropic state changes.

In the present method, an adjustment of the working volume during operation of the subject piston machine can also be made if at least one thermodynamic state variable of one of the working media in the chamber arrangement is determined and the time course of one of the working volumes of at least one of the chamber arrangements, which is substantially the sum its associated, inter-related partial working volumes is changed as a function of at least one determined state variable, whereby the approximate Carnot process modified and better adapted to changing boundary conditions, such as the available heat energy. This means that subsequent runs of the cycle may be different with respect to their state points.

Instead of directly determining a thermodynamic state variable or additionally at least one measured variable, in particular the position of one of the pistons, which are determined by the working medium or the upper or lower process temperature available for the cycle, can be determined is associated with a thermodynamic state quantity of one of the working media in the chamber arrangement, and the time course of one of the working volumes of at least one of the chamber arrangements, which is essentially the sum of the associated, associated partial working volumes, are changed as a function of the at least one determined measured variable , It is irrelevant whether a thermodynamic state variable is actually derived from the measured variable determined and / or whether it is still other measures or specifications would be required.

• Fig. 1 eine schaubildliche Ansicht einer erfindungsgemäßen Kolbenmaschine mit drei Kolben, die jeweils mit einer Kurvenscheibe verbunden sind;
• Fig. 2 eine schaubildliche Ansicht eines alternativen Wärmeübertragungskörpers für den Einsatz in einer Kammer einer erfindungsgemäßen Kolbenmaschine;
• Fig. 3a eine schaubildliche Ansicht eines spiralenförmigen Wärmeübertragungskörpers;
• Fig. 3b bzw. 3c jeweils schaubildliche Teilschnittansichten des Wärmeübertragungskörpers gemäß Fig. 3a in einer Kammer in einer teilweise offenen bzw. einer vollständig komprimierten Stellung;
• Fig. 4a bzw. 4b schematische Grundrisse zweier verschiedener Kammergeometrien, mit kreisrunden bzw. elliptischen Grundflächen;
• Fig. 5 eine schaubildliche Ansicht eines Rollelements mit seitlichen Führungsrollen;
• Fig. 6 eine teilweise Schnittansicht eines alternativen Rollelements mit zwei Profilrollen;
• Fig. 7 eine schematische Ansicht einer drehsymmetrischen Kurvenscheibe, mit welcher drei Kolben verbunden sind, entlang einer Drehachse;
• Fig. 8 eine schematische Teilschnittansicht durch eine Vorrichtung mit zwei artverwandten Kolben verschiedener Kammeranordnungen, einer gemeinsamen Motor-Generator-Einheit und zwischengeschaltetem Zahnradgetriebe und links-/rechtsläufigem Doppelkugelgewindetrieb;
• Fig. 9 ein Temperatur-Entropie-Diagramm des idealen Carnot-Prozesses;
• Fig. 10 ein Druck-Volumen-Diagramm des idealen Carnot-Prozesses;
• Fig. 11 ein Diagramm der verschiedenen Teil-Arbeitsvolumina einer Kammeranordnung mit drei Kammern als Funktion der Zeit während eines Prozessdurchlaufes;
• Fig. 12 ein Diagramm der verschiedenen Teil-Arbeitsvolumina einer Kammeranordnung mit zwei Kammern als Funktion der Zeit während eines Prozessdurchlaufes;
• Fig. 13 ein Diagramm der verschiedenen Teil-Arbeitsvolumina einer Kammeranordnung mit zwei Kammern als Funktion der Zeit während eines Prozessdurchlaufes, wobei die Zustandsänderungen im Vergleich zu Fig. 12 in anderen Kammern stattfinden;
• Fig. 14 eine weitere Variante des zeitlichen Verlaufs der einzelnen Teil-Arbeitsvolumina;
• Fig. 15 ein Diagramm der verschiedenen Teil-Arbeitsvolumina einer Kammeranordnung mit vier Kammern als Funktion der Zeit während eines Prozessdurchlaufes; und
• Fig. 16a-c schematisch verschiedene Arten von Federelementen zur Unterstützung eines Betätigungsmittels.

The invention will be explained below with reference to particularly preferred embodiments, to which it should not be limited, and with reference to the drawings. In detail in the drawing:

• Fig. 1 a perspective view of a piston engine according to the invention with three pistons, which are each connected to a cam;
• Fig. 2 a perspective view of an alternative heat transfer body for use in a chamber of a piston engine according to the invention;
• Fig. 3a a perspective view of a spiral-shaped heat transfer body;
• Fig. 3b and FIG. 3c are perspective partial sectional views of the heat transfer body according to FIG Fig. 3a in a chamber in a partially open or a fully compressed position;
• Fig. 4a or 4b schematic plan views of two different chamber geometries, with circular or elliptical bases;
• Fig. 5 a perspective view of a rolling element with lateral guide rollers;
• Fig. 6 a partial sectional view of an alternative rolling element with two profile rollers;
• Fig. 7 a schematic view of a rotationally symmetric cam, with which three pistons are connected, along an axis of rotation;
• Fig. 8 a schematic partial sectional view through a device with two related pistons of various chamber arrangements, a common motor-generator unit and intermediate gear transmission and left / right-handed Doppelkugelgewindetrieb;
• Fig. 9 a temperature entropy diagram of the ideal Carnot process;
• Fig. 10 a pressure-volume diagram of the ideal Carnot process;
• Fig. 11 a diagram of the various partial working volumes of a chamber arrangement with three chambers as a function of time during a process run;
• Fig. 12 a diagram of the various partial working volumes of a chamber assembly with two chambers as a function of time during a process run;
• Fig. 13 a diagram of the various partial working volumes of a chamber assembly with two chambers as a function of time during a process run, the state changes compared to Fig. 12 take place in other chambers;
• Fig. 14 a further variant of the time course of the individual partial working volumes;
• Fig. 15 a diagram of the various partial working volumes of a chamber arrangement with four chambers as a function of time during a process run; and
• Fig. 16a-c schematically different types of spring elements to support an actuating means.

In Fig. 1 For example, a piston engine 1 is shown for converting heat to work or for heating or cooling by the expense of labor. The piston engine 1 has three chambers 2, 3, 4, each with one of the respective chamber 2, 3, 4 associated piston 5, 6, 7. The three chambers 2, 3, 4 together form the single chamber assembly 8 of the piston engine 1. The chambers 2, 3, 4 are connected by connecting channels 9, 10 between the chambers 2 and 3 or 3 and 4, wherein between the two outer chambers 2, 4 no direct connection channel exists, but these two chambers 2, 4 only through the middle chamber 3 communicate with each other through. The chambers connecting the chambers 2, 3, 4 connecting channels 9, 10 are to avoid dead space (dead space) with as small as possible, but the requirements of the most feasible without resistance flow through volumes.

In each chamber 2, 3, 4, a single piston 5, 6, 7 is arranged. However, the cross sections of the pistons 5, 6, 7 are different between the chambers 2, 3, 4. Each piston 5, 6, 7 is connected to an actuating means in the form of a cam 11, 12, 13, wherein the three cam discs 11, 12, 13 are rotatably connected to a common axis 14. The cams 11, 12, 13 control the movement of the respective piston 5, 6, 7 or are arranged for the transmission of power to and from the piston 5, 6, 7. The axis 14 of the cams 11, 12, 13 is in a frame 15, which at the same time carries the chamber assembly 8. The pistons 5, 6, 7 are arranged vertically above the axis 14 of the cams 11, 12, 13 and connected via connecting elements 16 with the cams 11, 12, 13.

The connection of the pistons 5, 6, 7 with the cams 11, 12, 13 works mainly on arcuate rolling elements 17, which are mounted on the cams 11, 12, 13 and are connected via piston rods 18 with the piston 5, 6, 7 in connection , The rolling elements 17 (see. Fig. 5 for a detailed illustration) are also also mounted on lateral guide rails 19 in order to prevent any losses in the power transmission, for example in the form of lateral force components. In each case two laterally attached to the rolling elements 17 guide rollers 20 (see. Fig. 5 ) are in contact with a guide rail 19 on each side.

The cams 11, 12, 13 have circumferentially sections with a radially variable distance to the axis of rotation 14 of the cam 11, 12, 13 open profile groove 21, in each of which a profile roller 22 of the rolling elements 17 engages. The profile groove 21 is characterized by a thinner compared to the cam 11, 12, 13 side wall 23, which increases the cam 11, 12, 13 radially outward, and by a substantially the outer edge 24 of the cam 11, 12, 13 in the course following outer wall 25 is formed. The function of the outer wall 25 is to be able to exert tensile forces on the pistons 5, 6, 7 in addition to the pressure forces exerted by the cam 11, 12, 13. In sections 26, which respectively correspond to a dead phase of the respective cam 11, 12, 13 associated piston 5, 6, 7, i. a completely pushed into the respective chamber 2, 3, 4 position of the piston 5, 6, 7, the profile groove 21 may therefore be interrupted and the profile roller 22 may be mounted only on the outer edge 24 of the cam 11, 12, 13, as starting from this position no tensile forces on the part of the piston 5, 6, 7 are possible.

The top of each rolling element 17 is rigid via an adjusting element 27, by means of which the distance between the rolling element 17th and the piston 5, 6, 7 is exactly adjustable, connected to a piston rod 18. At the other end of the piston rod 18, the actual piston 5, 6, 7 is arranged, wherein the three pistons 5, 6, 7 are designed differently according to their different tasks. Two of the piston rods 18 of the pistons 5, 6 are each surrounded by a jacket 18 'which thermally isolates the piston rod from the environment.

The left piston 5 is arranged in a warm chamber 2, that is, the working temperature of this chamber 2 is higher than that of the cold chamber 4 on the right side. Accordingly, the piston 5, as well as the side wall 28 of the hot chamber 2 is insulated to the outside, which is indicated by insulating layers 29, wherein in the insulating layer 29 a plurality of mirrored heat shields are integrated to minimize heat transfer by radiation. The insulating layer 29 itself consists of airgel. But it is also possible to remove the airgel and to evacuate the space thus liberated, since this space is stable and airtight. Instead of the airgel but other available insulation materials such as mineral wool can be used. In addition, the left and middle chambers 2, 3 of the chamber assembly 8 are only connected in each case via three pins 29 ', which in turn are hollow and made of a material with poor thermal conductivity, with the main body 8' of the chamber assembly 8. The inner surface of the main body 8 'of the chamber assembly 8 and the outer surface of the left and middle chambers 2, 3 span, so to speak, between them the space occupied by the insulating layer 29. In the upper part of the chamber 2, a heat transfer body 30 is fixed, which is surrounded by a heating chamber 31. The heat transfer body 30 thus separates the heating chamber 31 from the remaining chamber 2 and the partial working volume 33 of the warm chamber 2. For bottom facing the piston 5, the heat transfer body 30 heat transfer surfaces 34 to increase the surface of the warm chamber 2 by the bottom surface follows a serrated pattern, wherein the inclined located in the warm chamber 2 heat transfer surfaces 34 of the teeth are arranged so that their upper and lower edges 35, 36 each lie in a plane and in plan view with the axis a connecting channel 9 to the middle chamber 3 a right angle. On the opposite upper side of the piston 5, a complementary heat transfer body 37 is arranged, which is therefore also serrated and is moved with the piston 5, wherein the teeth are conclusively inserted into the interstices of the teeth of the upper heat transfer body 30, so that when fully into the chamber 2 guided piston 5 substantially no dead space between the heat transfer bodies 30, 37 remains. Accordingly, the partial working volume of the warm chamber 2 is limited by the two heat transfer bodies 30, 37 and the inner surface of the side wall 28 of the chamber 2 and the cylinder. The heating chamber 31 has on both sides of line connections 38, 39, which allow the supply and removal of a heating medium, for example, warm air or liquid, in or out of the heating chamber 31, so that the temperature of the upper heat transfer body 30 and the lower heat transfer body 37, which with the former during a dead phase over a large area in contact, can be brought practically to those of the heating medium. In this case, both the line connections 38, 39 as well as the upper side of the heating chamber 31, the same insulation 29 as the side wall 28 of the hot chamber 2 and the piston fifth

The connecting channel 9 to the middle chamber 3 is arranged in the side wall 28 of the hot chamber 2 approximately at the level of the lower edges 36 of the teeth of the upper, immobile heat transfer body 30. In order to facilitate the flow of the working medium through the connecting channel 9 and into the middle chamber 3 in the compression of the warm chamber 2, the lower tips of the upper heat transfer body 30 and the feet (ie in the lower region of the teeth) of the lower heat transfer body 37 are narrow Passage channels 40 interspersed, which allow an abbreviation of the flow of the working medium. In a fully compressed position of the piston 5, ie when the piston 5 is fully inserted into the chamber 2 (see piston 7 in the cold chamber 4), the passageways 40 of the two heat transfer bodies 30, 37 open into passageways 40 of the other, respectively Heat transfer body 37, 30. Preferably, in this position all the passage channels 40 are in a plane and at the height of the connecting channel. 9

The middle chamber 3, which is connected by the short connecting channel 9, which is only long enough to traverse the side walls 28, 41 of the warm chamber 2 and the middle chamber 3 by the shortest route, with the warm chamber 2, also has a Circular base on, however, more than twice as large as that of the warm chamber 2. The connecting channel 9 is inserted in each case with a spherical end hinged and slightly displaceable in the side walls 28, 41 of the warm chamber 2 and the middle chamber 3, whereby a slight change in position of the warm and middle chamber 2, 3 is taken into account during operation. The interior of the middle chamber 3 is purely cylindrical, i. no heat transfer surfaces are provided to increase the surface area. On the contrary, both the side wall 41 of the chamber 3 and the upper inner surface and the inside of the piston 6, i. the part of the working volume of the middle chamber 3 facing side of the arranged in the chamber 3 piston 6, isolated, so that heat exchange with the working medium is avoided as much as possible. The piston 6 reduced in the illustrated compressed position, the available part-working volume of the chamber 3 to substantially zero, the flat top of the piston 6 is applied to the upper flat inner side of the chamber 3 conclusive. So that the working medium can easily leave the chamber 3 during compression, the upper flat inner side of the chamber 3 is arranged at the level of the connecting channel 9 to the warm chamber 2.

Opposite the connecting channel 9 to the warm chamber 2, the side wall 41 of the middle chamber 3 has a further connecting channel 10, which connects the part-working volume of the middle chamber 3 with that of the cold chamber 4. The two connection channels 9, 10 are preferably at the same height and in this example even on a line. For improved removal of the working medium, the upper inner side of the chamber 3 has a peripheral recess in the manner of an outer drainage channel 42 so that working fluid forced outwardly from the piston 6 during compression reaches the lateral connection channels 9, 10 through the annular drainage channel 42 can. This outflow option is particularly advantageous because, depending on the position in the cycle each only the outflow through one of the two of the connecting channels 9, 10 is provided or possible, so that the working medium can pass through the drainage channel 42 from one side better to the other.

The cold chamber 4 connected to the middle chamber 3 and opposite the warm chamber 2 has heat transfer bodies 43, 44 comparable to the warm chamber 2, whose serrated surface forms oblique heat transfer surfaces 45 for enlarging the surface of the interior of the chamber. In contrast to the warm chamber 2, neither the side wall 46 of the chamber 4 nor its upper side 47 or the piston 7 is insulated to the outside here. On the contrary, convectors 48 are connected to the chamber 4 and the piston 7 on all sides, so that the working temperature of the cold chamber 4 can be kept as equal as possible to the ambient temperature of the piston engine 1. The convectors 48 have a basically with the heat transfer bodies 43, 44 comparable, serrated shape, but whose edges are aligned at right angles to the edges of the arranged in the chamber 4 heat transfer body 43, 44. Of course, other known heat exchangers could be used instead of the convectors 48.

Rotates the axis 14 in one direction, so that the approximate Carnot process is passed right-handed, the piston engine 1 of the invention can be operated as an engine (engine), wherein on the axis 14 mechanical work is delivered, the warm chamber 2 (the Working medium) is supplied at the upper process temperature heat and the cold chamber 4 at the lower process temperature heat as so-called waste heat to the environment gives to compensate for the Entropiebilanz. If the axis 14 rotates in the other direction, so that the approximate Carnot process is passed through to the left, then the piston machine 1 according to the invention can be operated as a working machine (refrigeration machine, heat pump), mechanical work being supplied to the axis 14, the cold chamber 4 Heat is supplied at the lower process temperature or the cold chamber 4 of the outer environment at the lower process temperature heat and withdraws the warm chamber 2 at the upper process temperature heat as useful heat or waste heat, depending on the application and Viewing, gives to balance the Entropiebilanz again. The shapes or contours of the cams 11, 12, 13 or the movement profiles defined by these are different not only between the outer chambers 2, 4 and the middle chamber 3 but also between the outer chambers 2, 4, the difference the movement profiles of the outer chambers 2, 4 associated piston 5, 7 shows mainly by their opposite sense of direction.

In Fig. 2 For example, a garland heat transfer body 49 is shown in a partially expanded position. As can be clearly seen from the figure, the surface of this heat transfer body 49 exceeds its base area by a multiple. The garland-like heat transfer body 49 is made up of a stack of a plurality of annular discs 50, which are connected to each other on both sides, ie with the two adjacent discs 50. The outer circumference of all discs 50 is the same, but the radius of the inner edge 51 increases from top to bottom in the stack, ie the lowermost annular disc 50 is narrower than the discs 50 above. The garland-like structure is achieved by forming the connections 52 to the adjacent discs 50 only along a connecting line passing through the center of the discs 50 and crossing the connecting lines at the top and bottom of each disc 50, in particular at right angles.

A variant of a garland-like heat transfer body 49 is in Fig. 3a shown, wherein this heat transfer body 53 has substantially the shape of a spiral. In a partially expanded position, as in Fig. 3a As shown, each turn of the spiral contributes to the enlargement of the surface, ie, the surfaces of each individual turn form the heat transfer surfaces 54 for a working fluid therebetween. As with the heat transfer body 49 described above, the inner radius of the spiral increases from top to bottom, so that the spiral forms a conical inner space 55.

In Fig. 3b and 3c is the spiral heat transfer body 53 according to Fig. 3a shown arranged in a chamber 56 with a piston 57. Instead of the spiral-shaped heat transfer body 53, the heat transfer body 49 according to FIG Fig. 2 can be used, so that the following description for the other heat transfer body 49 is analogously applicable. The heat transfer body 53 shown may be connected both to the top with the inside of the chamber 56 and down to the top of the piston 57. Such a connection is required when the position of the free state of the heat transfer body 53 is smaller than the maximum expanded position in the chamber 56, since in this case the heat transfer body 53 has to be pulled apart against the spring force exerted by it. In Fig. 3b a partially expanded position is shown. Inside the heat transfer body 53, a conical pin 58 can be seen, which projects into the conical inner space 55 formed by the heat transfer body 53, the radius of the pin 58 on its underside 59 corresponding to the inner radius of the lowermost layer 60 of the heat transfer body 53. In addition, the radius of the pin 58 at the upper end 61 corresponds to the inner radius of the uppermost layer 62 of the heat transfer body 53. Thus, in a compressed position, the pin 58 completely fills the heat transfer body 53, as in FIG Fig. 3c can be seen. In this case, the layers 63 of the heat transfer body 53 lie directly against one another, so that substantially no dead space remains in the respective chamber 56.

Of course, other forms are conceivable for the chambers instead of the previously described cylindrical base surfaces. For example, the show Fig. 4a and 4b a comparison of two chambers 64, 65 and 66, 67 with circular or elliptical bases, the areas are equal in magnitude. As can be seen from the comparison, with equally long connecting channels 68 or 69 between the mutually facing side walls of the elliptical chambers 66, 67 more space than in the circular chambers 64, 65, so that the elliptical chambers 66, 67 better insulated from each other thermally can be as the circular chambers 64, 65.

In Fig. 5 is one of the rolling elements 17 according to Fig. 1 increases shown. The rolling element 17 consists essentially of a bow-shaped or bridge-shaped basic body 70 with two side walls 71, 72 and a bridge element 73, which connects the two side walls 71, 72. Between the two side walls 71, 72, a profile roller 22 is mounted on one side, so that between the profile roller 22 and the opposite side wall 72 remains a distance. On the outer side of the two side walls 71, 72 are each two smaller guide rollers 20 are mounted, whose axes are angled relative to an axis of the profile roller 22, but lie advantageously with this in a plane. All rollers 22, 20 are equipped with largely frictionless ball bearings. At the top of the bridge element 73, a connecting pin 74 is formed, which has a passage opening 75, for example for a coupling pin, and for the connection to a piston rod 18 (see. Fig. 1 ) is set up.

An improved variant of the rolling element 17 according to Fig. 5 is in Fig. 6 shown together with a sectional view of the profile groove 21 of a cam 11, said rolling element 76 instead of a single profile roller 22 has two independent profile rollers 77, 78 of different diameters. The larger profile roller 78 is designed to bear on an outer edge 24 of the cam 11, while the smaller profile roller 77 is adapted to bear against the outer wall 25 of the profile 21. Accordingly, the two profile rollers 77, 78 rotate in a movement of the cam 11 in opposite directions of rotation. The advantage of such a roller arrangement is that the two profile rollers 77, 78 - in contrast to a single profile roller 22 which alternates at the outer edge 24 of the cam 11 and the outer wall 25 of the profile 21 - their direction of rotation at any time during a complete Rotation of the cam 11 must change.

In Fig. 7 schematically is an expansion possibility of the piston engine 1 according to Fig. 1 shown. Besides, in addition to the in Fig. 1 shown two further piston assemblies 79, 80 may be arranged symmetrically about the axis of rotation 81 of the cam 82, wherein three similar pistons 83, 84, 85 of the various piston assemblies 8, 79, 80 are connected to a common cam 82. In this case, the cam disk 82 has a symmetry corresponding to the piston arrangements 8, 79, 80, in this case a threefold rotational symmetry. In such a piston machine 86, the same state changes of identical circular processes are carried out in the chamber arrangements 8, 79, 80 at the same time, whereby forces acting on the cam disk 82 always have the same magnitude and symmetrical forces on the cam disk 82, so that no resulting radial force acts on the rotation axis 81 acts and thus losses, for example, in the bearings of the rotation axis 81, can be reduced and a nearly vibration-free operation of such a piston machine is given. Furthermore, the mass inertia effects of the pistons 83, 84, 85 of the chamber arrangements 8, 79, 80 are also canceled out. In order to achieve a similar effect by means of another structure, instead of the cam 82, a cam ring could be used with an inner diameter placed cam element, wherein the symmetrically arranged chamber assemblies are centered about the axis of rotation of the ring, wherein the rolling elements outwardly on the cam elements of the cam ring would be directed.

Fig. 8 shows a partial sectional view of a piston engine 87 with opposing chamber arrangements, of which only schematically the related pistons 88 are shown with their common actuating means 89, a motor-generator unit, which is adapted for both the application and for receiving torques. The actuating means 89 and the actuating means 89 associated piston 88 is a common gear transmission 90 with the gears 91, 92 and one ball screw spindle 93 interposed, one is the left-hand and the other clockwise. Both ballscrew spindles 93 have the same pitch and number of gears, are non-rotatably connected to each other or are to be understood as a single double ball screw with opposing threads, which is mounted on two bearings 94. The nuts 95, wherein a nut 95 and a ball screw 93 together form the ball screw, are each connected via a bearing between two rollers 96 guide frame 97 with the piston 88. The linear movement of at least one of the pistons 88 is recorded using a displacement measurement 98. In this arrangement, the inertia forces of the pistons 88, assuming their same embodiment of course, and the rigidly connected elements, the same design also provided assuming, on.

As explained in detail at the outset, the - basically known - comparison process of the piston machine according to the invention is the Carnot process. This in Fig. 9 Diagram 99 qualitatively describes the relationship between temperature and entropy of the working medium during a passage of the cycle. The inherent entropy of the working medium is plotted on the abscissa axis 100, while the temperature of the working medium is plotted on the ordinate axis 101. The four edges 102, 103, 104, 105 of the rectangular path 106 of the cycle process each represent a state change of the working medium and connect four state points 107 in the corners of the rectangle. The edges 102, 104 parallel to the axis of abscissa 100 corresponding to isothermal state changes 102, 104 at an upper temperature To and a lower temperature Tu and the edges 103, 105 parallel to the ordinate axis 101 correspond to isentropic state changes 103, 105 at different entropy levels. Depending on whether the reciprocating engine 1 is used to convert heat to work or to heat or cool by the application of labor, the thermodynamic state of the working medium that is changing during the process follows the rectangle 106 clockwise and counterclockwise, respectively.

In Fig. 10 is the same - basically known - circular process as in Fig. 9 represented in another coordinate system or diagram. On the abscissa axis 108 of this pV diagram 109, the working volume of the working medium and the ordinate axis 110 whose pressure is plotted. Successive state points 107 in the process run lie both at different pressure and volume levels, ie there is neither an isobaric nor an isochoric state change. The two isothermal state changes 102, 104 are shown as solid lines and the two isentropic state changes 103, 105 as dashed lines. As from this diagram 109 especially clearly seen, in the Carnot process shown, the volume changes, the absolute difference value, during the isothermal state changes 102, 104 vary in size, in particular, the required volume change at the higher temperature To - ie in the warm chamber 2 - considerably smaller than that In addition, the volume change during the isentropic state changes 103, 105 is also dependent on whether it is the isentropic compression or the isentropic expansion: for example, in a heat engine (illustrated process, the volume change during the isentropic compression 105 is smaller than during the isentropic expansion 103. The working volumes V1, V2, V3, V4 are plotted on the abscissa axis 108 in the four state points 107 on the abscissa axis 108 and on the ordinate axis 110 on the abscissa axis 108 Completeness h alber the associated pressures p1, p2, p3, p4 drawn.

The Fig. 11 to 15 each show a qualitative diagram of the partial working volume of the chambers of a chamber arrangement of the piston engine according to the invention as a function of time and for a complete run 113 or complete cycle. On the ordinate axis 111, on which the partial working volumes are plotted, are also in each case for orientation in the diagram in Fig. 10 plotted volume levels V1, V2, V3, V4 at the state points 107 drawn. On the abscissa axis 112, on which the time or the position within the passage 113 is plotted, are also the state changes, as in the diagrams in FIGS. 9 and 10 referred to, wherein during some time sections, such as when the working fluid remains in a state point 107, no change in state takes place.

In Fig. 11 is the course of the partial working volumes of the three chambers 2, 3, 4 in a piston engine 1 according to Fig. 1 shown. The solid line 114 represents the partial working volume or its course in the warm chamber 2, the dashed line 115, the partial working volume in the cold chamber 4 and the dotted line 116, the partial working volume in the middle chamber 3. At the origin of Timeline 112 is located the working medium completely in the warm chamber 2 and expands during the first period 102 (of course, approximately) isothermal, that is, heat energy is supplied. Once the isothermal expansion 102 is completed, the working medium is conveyed from the warm chamber 2 into the middle chamber 3 by compressing the partial working volume of the warm chamber 2 and expanding that of the middle chamber 3 at the same rate at the same time. In the meantime, the thermodynamic state of the working medium does not change, ie, despite a constant working volume V2, this transition does not constitute an isochronic change of state, because this process is to be understood as adiabatic due to the short duration and the embodiment of the middle chamber 3 already described. As soon as the working medium has been conveyed completely into the middle chamber 3 and the partial working volume 114 of the warm chamber 2 has thus fallen to zero, the isentropic expansion 103 or its time interval, which is significantly faster than the isothermal expansion 102, begins in the middle chamber 3 expires, so that a heat exchange is avoided as possible. As soon as the working medium has reached the maximum working volume V3, it is conveyed from the middle chamber 3 into the cold chamber 4, where then the isothermal compression 104 takes place and thermal energy from the working medium to the chamber 4 and in consequence the environment is released. Thereafter, the working medium changes again into the middle chamber 3, in which after the chamber change, the isentropic compression 105 takes place. After a renewed change of chamber back into the warm chamber 2, the next pass 113 begins. As can be seen from the course of the partial working volumes, at least either the partial working volume 114 of the warm chamber 2 or 115 of the cold chamber 4 is at any time Essentially zero. During the isentropic state changes 103, 105, even both partial working volumes 114, 115 are substantially zero. In addition, from the diagram in Fig. 11 It can be seen that the two isotropic state changes 103, 105 require considerably less time than the two isothermal state changes 102, 104, the isentropic expansion 103 at the same time covering the largest volume range and one of the smallest time segments, so that the rate of volume change during the isentropic expansion 103 one of the biggest is. Furthermore, is from the diagram in Fig. 11 It can be seen that the working volume is always essentially subdivided into the partial working volumes 114, 115, 116 of one or two chambers 2, 3, 4.

The diagrams in Fig. 12 to 14 show curves of the partial working volumes of a piston engine with one or more piston assemblies, each with only two pistons. With two chambers it can - in contrast to in connection with Fig. 11 illustrated operation of a 3-chamber machine - no separate piston for the isentropic state changes 103, 105 give. Since the isentropic state changes 103, 105 thus have to take place in a chamber 2, 4 which is subject to the process temperatures To, Tu and preferably heat transfer surfaces 34, 45, a heat exchange can be prevented only via the highest possible rate of change of state 103, 105. In addition, the working medium must of course be transported directly from the warm chamber into the cold chamber or vice versa.

In the method according to Fig. 12 After the isothermal expansion 102, the isentropic expansion 103 still takes place in the warm chamber, and the working medium is conveyed into the cold chamber 4 at a maximum volume V3 during a chamber change 117. There, the isothermal compression 104 is followed by the isentropic compression 105 before a chamber change 118 is completed back into the warm chamber. The chamber changes 117, 118 accordingly always follow an isentropic state change 103, 105.

In contrast to Fig. 12 be in a method according to Fig. 13 the chamber changes 117, 118 performed before the isentropic state changes 103, 105. Consequently, the isentropic expansion 103 is already in the cold chamber 4 immediately before the isothermal compression 104 and after a chamber change 118 is followed by the isentropic compression 105 and immediately thereafter the next isothermal expansion 102 in the warm chamber. This method has the advantage that only the cold chamber has to hold the maximum volume V3 and the chamber cross-section can be adjusted accordingly.

While in the previous methods and operating modes of change the working medium from one chamber to the next as a separate step - but without changing the thermodynamic state of the working medium - is performed, takes place in the method according to Fig. 14 a chamber change takes place simultaneously with an isentropic state change. At the isothermal expansion 102, which naturally takes place in the warm chamber, immediately begins a compression of the warm chamber, which is accompanied by a much faster expansion of the cold chamber. The working volume is thus increased in total, which approximates an isentropic expansion at a correspondingly high speed. At the end of this combined chamber change 119, the isothermal compression 104 can begin immediately. Once this is completed, the second chamber change 120 is parallel to the isentropic compression, ie the cold chamber compresses much faster than the warm chamber expands. At the end of this process, the isentropically compressed working medium is already completely in the warm chamber. This method thus effectively manages with only four steps during a pass 113.

There are also mixed forms in the diagrams of Fig. 12 to 14 possible methods, which will not be discussed in more detail because of their partial analogies to the already explained methods.

The operation of a four-chamber piston engine according to the invention is finally in Fig. 15 schematically illustrated by the progressions of the part-working volumes. In this case, a separate chamber is provided for each of the isentropic expansion 103 and the isentropic compression 105. The working medium circulates in one direction through the four chambers (the warm chamber can be connected directly to the cold chamber via another connecting channel), each separate work steps for the thermodynamically static chamber changes 121, 122, 123, 124 are provided. The diagram shows the course of the partial working volume in the warm chamber 114, in the cold chamber 115 and in the isentropically expanding chamber 125 and the isentropically compressing chamber 126. When the isothermal compression 104 starts exactly at half of the cycle 113, or the expansion part and the compression part of a run 113, respectively take the same length, in such an arrangement, two working volumes can work simultaneously in a chamber arrangement, with the working volumes are always in or between opposite chambers and the connecting channels should be equipped with valves. From a chamber arrangement with 6 chambers two or more working volumes are possible with even more chambers without valves.

The illustrated and described embodiments may, of course, be modified or extended in the context of the invention in a professional manner. For example, instead of the external heat supply by means of a heating medium, internal combustion can also be provided in one of the chambers, which can be adapted to the movement profile of the piston arranged in the warm chamber, for example by a time-variable quantity of the supplied fuel. Further possibilities of heat transfer to one of the pistons, e.g. Bundled sunlight or a flame directed from the outside onto a heat transfer body are likewise within the scope of what the person skilled in the art considers as use.

For the sake of brevity it should be mentioned that the in the Fig. 11 to 15 shown temporal sequences of the partial working volumes, taking into account the respective projected in the stroke direction piston surface as temporal sequences of the piston positions within their chambers can be understood, which in turn corresponds to the movement profiles of the respective pistons. If a movement profile begins and ends in each case during a dead-phase section, these dead-phase sections together result in a dead-phase.

In Fig. 16a-c spring elements 127, 128, 129, 130 for supporting an actuating means 131 are shown. In Fig. 16a For example, a counter-rotating piston 132 and a coil spring 128 are shown. The piston 132 is received in a closed cylinder 133, so that each compression of the piston 132 is accompanied by compression or decompression of a compression medium 134 held in the cylinder 133. Both spring elements 127, 128 are connected via a spar 135 and a rocker 136 with a guide fork 137, which in such a way with a Piston rod 138 of the piston 139 of the reciprocating engine is coupled, that a linear piston movement of the piston 139 is transmitted to a pivotal movement of the strut 135 and vice versa. Based on the lever arm with respect to the rocker 136, the extent of support by the spring elements 127, 128 can be determined by design. In Fig. 16b the spring element 129 is integrated directly into the cylinder 140 of the piston 139. Here, a closed chamber 141 with a compression medium 134 is provided below the piston 139. Fig. 16c shows a magnetic spring element 130, which is formed with each other attractively oriented ring magnet 142, 143. The ring magnets 142, 143 are arranged in a circle around the piston rod 138 and support a compression movement of the piston 139 while they deprive energy from a decompression movement and buffer it as potential energy.

The fields of use of the invention, i. The piston engine according to the invention and the method according to the invention are diverse. In particular, depending on the design and mode of operation of the reciprocating machine, uses may be made to drive a generator to produce electrical energy or to generate electrical energy directly by means of the motor-generator unit or any heat pump, e.g. for a family home or as a chiller for industrial applications, into consideration.

Claims (5)

1. A piston machine (1) for converting heat into work or for heating or cooling by the application of work, having at least one chamber arrangement (8), which comprises at least two chambers (2, 3, 4) connected by at least one connecting duct (9, 10), wherein at least two of the chambers (2, 4) are substantially thermally insulated against one another and have different capacities and working temperatures, and having pistons (5, 6, 7) which are impermeable to a working medium and are movably arranged in their respective chambers (2, 3, 4) to vary a partial working volume bounded by the chamber (2, 3, 4) and the piston (5, 6, 7), wherein at least one of the chambers (2, 4) comprises thermal transfer surfaces (34, 45) to increase the surface area thereof, wherein the pistons (5, 6, 7), or elements connected therewith, are connected to actuating elements for defining motion profiles for each of the pistons (5, 6, 7), wherein the actuating elements are designed to define at least two different motion profiles of the pistons (5, 6, 7) of the chamber arrangement (8), characterized in that the chamber arrangement (8) comprises three chambers (2, 3, 4), wherein a middle one of the three chambers (3) is connected by the at least one connecting duct (9, 10) to the two chambers (2, 4) having different capacities and working temperatures and has a larger capacity than that of the two chambers (2) having a relatively high working temperature, wherein due to its shape the middle chamber (3) has a larger distance, in terms of the arithmetic mean, between a volume element, which is assumed to be as small as desired, of its partial working volume extended to a reference volume and its inner chamber surface limiting the partial working volume, than at least one of the at least two chambers (2, 4) connected by at least one connecting duct (9, 10), wherein the reference volume is constituted by the smaller volume of the two maximum partial working volumes obtained during operation by the chambers (3, 2 or 3, 4) compared to one another, and the inner chamber surface limiting the partial working volume, of course, also comprises the possible thermal transfer surfaces (34, 45) to increase the surface of the chamber (2, 4), and comprises the surface areas adjacent the partial working volume of the piston (5, 6, 7) arranged in the chamber (2, 3, 4), and wherein the distance is defined to be the length of the shortest connecting line.
2. The piston machine (1) according to claim 1, characterized in that at least one of the actuating elements (89) comprises a motor-generator unit and the piston(s) (88) allocated to the actuating elements (89) or elements connected thereto is/are connected to the rotor of the motor-generator unit.
3. The piston machine (1) according claim 1 or 2, characterized in that a gear transmission, in particular a pantograph-like coupled gear, or a ball screw (93 and 95) is interconnected between at least one of the actuating elements (89) and the piston (88) allocated thereto.
4. The piston machine (1) according to one of claims 1 to 3, characterized in that due to its shape the middle chamber (3) has an at least 1.5 times larger distance in terms of the arithmetic mean, between a volume element, which is assumed to be as small as desired, of its partial working volume extended to the reference volume and its inner chamber surface limiting the partial working volume than at least one of the at least two chambers (2, 4) connected by at least one connecting duct (9, 10).
5. The piston machine (1) according to one of claims 1 to 4, characterized in that at least one of the pistons (5, 6, 7) is connected to a spring element, in particular a magnetic, mechanic or gaseous spring element to support the actuating element allocated to the piston (5, 6, 7).

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