DE102011055511A1 - Cyclic working piston machine used in heat pump, has electrodes that are arranged in electrical contact with liquid piston at a distance in relative to direction of movement of liquid piston and orientation of magnetic field - Google Patents

Abstract

The piston machine (1) has working chamber (3) to receive working medium (5). An electrically conductive liquid piston (7) positioned in channel adjacent to working space (9) moves such that volume of working chamber varies according to position of liquid piston. A magnet (13) generates magnetic field (15) which is perpendicular to movement direction of liquid piston at location of liquid piston. Two electrodes (19,21) are arranged in electrical contact with the liquid piston at a distance in relative to direction of movement of liquid piston and orientation of the magnetic field.

Description

The invention relates to piston engines, z. For use as an engine or work machine. In particular, the invention relates to cyclically operating piston engines with an electromechanical input and output, z. B. for use as a compression or expansion machine in thermodynamic cycles.

Piston machines enable the conversion of thermal and mechanical energy into one another by means of the realization of thermodynamic cyclic processes, but in the case of real, non-ideal cyclic processes always a part of the thermal energy is lost as unused waste heat, whereby the overall efficiency is reduced. This waste heat can z. B. used to operate a heat engine or to operate a thermoelectric generator and thus be made usable.

So describes z. B. the US Pat. No. 7 520 133 B2 a heat engine for obtaining mechanical energy from the exhaust heat of an internal combustion engine, wherein the heat engine has a plurality of voluminous accessories (eg., Heat exchanger, condenser, condensate pump).

The DE 10 2008 050 655 A1 describes a working according to the Stirling principle heat engine for using the exhaust heat of a motor vehicle, the heat engine having mechanically moving parts in the form of an expander with a cylinder and a piston, so that the heat engine is subject to a corresponding mechanical wear.

As another example, exhaust heat (eg, a vehicle) may be converted into electrical energy by means of a thermoelectric generator in the form of a Peltier element, although Peltier elements are susceptible to wear but have low efficiency (especially at low applied temperature differences).

The invention provides a piston machine is provided which has a long service life, allows high efficiency, versatile and is also compact, easy and inexpensive to produce.

In accordance with one aspect of the invention, a cyclically operating reciprocating engine is provided. The piston engine has a working space (or a working chamber) for receiving a working medium of the piston engine (eg a - gaseous or liquid - working fluid). The piston engine further comprises a liquid piston made of an electrically conductive liquid, wherein the liquid piston is arranged movably in a channel adjacent to the working space such that the volume of the working space varies according to the position (or according to the movement) of the liquid piston, wherein the working medium (which is in the working space) is in displacement interaction with the liquid piston. The piston machine also has a magnet which is designed and arranged such that the magnetic field generated by it at the location of the liquid piston has a component oriented perpendicular to the direction of movement of the liquid piston (so-called "vertical component") (ie not completely parallel to the field lines of the magnetic field to the direction of movement of the liquid piston). Finally, the piston machine has two electrodes, which are arranged in electrical contact with the liquid piston at a distance from each other such that the distance direction (ie the direction of the distance between the two electrodes) perpendicular to the direction of movement of the liquid piston and perpendicular to the orientation of the magnetic field ( or the vertical portion of the magnetic field) at the location of the liquid piston extending portion.

By the piston is designed as a liquid piston, the piston engine can be operated substantially without mechanical wear, thus allowing a long life; at the same time, the design with a liquid piston enables a compact, arbitrarily scalable and simple design of the piston engine. The piston engine can therefore be formed with small dimensions and thus correspondingly high resonance frequencies and can therefore be easily implemented as a high-speed piston engine. By means of the embodiment of the liquid piston made of an electrically conductive (or electrically conductive) material and the arrangement of the magnet and the two electrodes, both an electromechanical drive of the piston engine with the input of electrical energy and an electromechanical output of the piston engine with the extraction of electrical energy is possible, so that the piston engine can be used in many ways both as an engine and as a work machine. In addition, the direct coupling of the electromechanical drive allows high efficiency in the conversion of electrical, mechanical and thermal energy into each other.

The working medium in the working space can, for. B. be an (inert) gas. In order to operate the piston engine, it is possible - in a manner known per se for pressure-volume machines (such as, for example, piston engines) - to periodically return the liquid piston by means of alternating volume increase and volume decrease of the working medium to move, or alternatively by means of external driving of the liquid piston to a periodic reciprocation, the volume of the working space to increase and decrease alternately. The displacement interaction between the liquid piston and the working medium is realized by incorporating the piston engine in a thermal circuit, either caused by the movement of the piston displacement of the working medium or vice versa, the working fluid for the respective thermodynamic cycle process characteristic states in the pressure Passes through the volume temperature phase space (pVT phase space).

The electrically conductive liquid may, for. A liquid metal (eg a eutectic sodium-potassium alloy or gallium-indium-tin alloy), an ionic solution or ionic liquid; wherein the respective material is in the liquid state of aggregation at the operating temperature of the reciprocating engine.

The magnet can z. B. be a permanent magnet or an electromagnet. It can be provided to form and arrange the magnet in such a way that the magnetic field (or the associated field lines) generated by it at the location of the liquid piston runs (substantially) perpendicular to the movement or flow direction of the liquid piston, the field lines z. B. by means of a dedicated magnetic circuit of a soft magnetic material can be bundled and guided accordingly. Furthermore, provision may be made for the two electrodes to be arranged at a distance from one another such that the associated spacing direction is (substantially) perpendicular to the direction of the magnetic field at the location of the liquid piston and / or perpendicular to the direction of movement of the liquid piston.

The arrangement of the electrically conductive liquid piston, the magnet and the two electrodes forms an electromechanical transducer; where z. B. by a movement of the liquid piston along the longitudinal direction of the channel by means of the electromagnetic Lorentz force separation of unlike electric charges takes place and between the two electrodes, a corresponding electrical voltage is formed, so mechanical kinetic energy is converted into electrical energy; and conversely z. B. upon application of an external AC voltage to the two electrodes, a corresponding reciprocation of the liquid piston along the longitudinal direction of the channel is caused, ie electrical energy is converted into mechanical kinetic energy.

The liquid piston is movably arranged in a channel adjoining the working space, wherein the volume of the working space varies in accordance with the movement position of the liquid piston (eg by the liquid of the liquid piston flowing in and out of the working space). For example, it can be provided that a boundary surface of the working space is formed by the liquid piston, wherein the liquid piston (or an end face thereof) is in direct contact with the working medium or directly adjacent to the working medium.

According to one embodiment, the liquid piston is thermally isolated or decoupled from the working medium. According to this embodiment, a heat transfer between the liquid piston and the working medium can be effectively suppressed, whereby z. B. energy loss can be prevented by heating or cooling of the working fluid and thus the efficiency of the piston engine can be further increased.

The thermal insulation can z. B. be realized by means of a suitable choice of material of the working medium and / or the liquid piston as materials with a low thermal conductivity and / or low heat capacity.

According to one embodiment, the liquid piston is thermally isolated or decoupled from the working medium by means of a thermal insulation layer, which is arranged between the liquid piston and the working medium (eg at the corresponding end face of the piston); wherein the liquid piston is only indirectly adjacent to the working medium and is not in direct contact therewith.

The insulation layer may, for. A layer of barrier liquid (eg, an oil); wherein the barrier liquid z. B. is a liquid having a density which is between that of the liquid piston material and that of the working medium. Furthermore, the barrier liquid is preferably chosen such that it is chemically inert to the liquid piston material and the working medium. The thermal insulation layer can also act as a force-transmitting element, as corrosion protection for the electrically conductive liquid of the liquid piston and / or as contamination protection for the working medium. The insulating layer can also be a separating layer arranged between the piston and the working medium and made of a solid material (eg in the form of a foil).

According to a further embodiment, the piston machine is designed to act on the two electrodes with an external (periodic) alternating voltage (ie for applying an alternating voltage between the two electrodes), wherein the liquid piston by means of AC voltage (periodically) is reciprocated according to the frequency of the AC voltage and the volume of the working space varies according to the movement of the liquid piston.

According to this embodiment, the electromechanical transducer can function as a motor for driving the liquid piston, wherein the liquid piston can be vibrated by supplying electric energy and can act as a displacer for the working medium. Thus, the piston engine z. B. as a compressor or as a compression / expansion device in a via the working space or the working medium coupled thermodynamic cycle, such as a heat pump (or chiller) act.

According to a further embodiment, the piston machine is designed for the periodic, alternating pressurization and depressurization of the working space, whereby the volume of the working space varies periodically according to the temporal pressure variation and the liquid piston is reciprocated correspondingly (and by means of) the variation of the working space volume.

According to this embodiment, the electromechanical transducer can act as an output for coupling out electrical energy or work from the piston engine and thus as a current generator, wherein the liquid piston can be set into oscillating motion by means of the (periodic) pressure variation of the working medium and a corresponding alternating voltage between the two electrodes can generate.

The pressurization or pressure relief of the working space can be realized in a known manner for piston engines by incorporating the working space (and the working medium) in a thermodynamic cycle. So z. For example, it may be provided to realize a pressure variation of the working medium when the working space is closed (i.e., without exchange of working medium with an external system) by alternately heating and cooling the working medium. It may also be provided to implement a pressure variation by alternately introducing and discharging working medium into the working space (eg via inlet and outlet valves provided for this purpose on the working chamber); wherein it can additionally be provided to supply thermal energy to the working fluid when it is being introduced from the outside and / or to remove it during discharge.

Furthermore, the piston engine may have a control device which is designed such that the piston engine can be selectively switched into a motor mode or into a generator mode by it, wherein in the motor mode the two electrodes are subjected to an external alternating voltage and the electromechanical converter acts as a motor for driving the liquid piston, whereas in the generator mode the working space is subjected (externally) to a periodic pressure variation and the electromechanical converter acts as an electrical generator (so that an AC voltage can be tapped at the two electrodes).

According to a further embodiment, the working space and / or the channel are at least partially filled with a porous, open-pored material. According to this embodiment, the electrically conductive liquid of the liquid piston can be held by capillary forces and guided mechanically by the open-pore structure, so that a bumpless and / or position-independent operation of the piston machine is made possible.

According to a further embodiment, the piston engine has two working spaces, wherein the liquid piston is arranged such that it adjoins the one working space with its first end face and adjoins the other working space with its other end face (so-called double-acting piston machine). According to this embodiment, the piston engine by connecting a second working space to the electromechanical transducer as a double-acting pressure-volume machine (in short: "pV machine") to be executed, wherein an expansion of one of the working spaces associated with a compression of the other working space.

In accordance with another aspect of the invention, there is provided a dual piston engine having a first and a second piston engine according to any of the embodiments described above. A working chamber of the first piston engine is in fluid communication with a working space of the second piston engine via a thermal exchange device, wherein the thermal exchange device sequentially radiates a cooling device (for cooling the working fluid) in the direction from the working chamber of the first piston engine to the working chamber of the second piston engine, a regenerator (resp Heat buffer), and a heat exchanger (for exchanging heat with the working medium). Each of the two piston machines also has an associated electrically conductive liquid piston and an electromechanical transducer (with a magnet, two electrodes and the liquid piston).

The double piston engine can, for. B. be designed as alpha-Stirling machine, wherein the two liquid piston the high-temperature side piston and the low-temperature side of the piston alpha stirling machine, and wherein the first piston machine acts as a compression pV machine and the second piston machine as an expansion pV machine. In training or use of the double piston engine as an engine of the double piston engine (or the working fluid) by means of the heat exchanger of the thermal exchange device, thermal energy supplied from the outside, ie the heat exchanger acts as a heater; whereas when using the double-piston engine as a heat pump, the heat exchanger acts as a low-temperature cooling source (or as a cold heat exchanger), at which cold can be tapped. The realization of the thermodynamic cycle process via the mutually phase-shifted electrical control of the electromagnetic transducer of the two reciprocating engines, wherein the compression engine receives electrical work (ie acts as a motor) and the expansion machine electrical work (ie acts as a generator). In training or use of the double-piston engine as an engine, the output from the expansion machine electrical work is greater than the recorded by the compression machine electrical work; whereas, in training or use of the double piston engine as a heat pump (or chiller), the electrical power output is less than the recorded electrical work.

According to another aspect of the invention, there is provided a multi-piston machine having a plurality of double-acting reciprocating engines according to the above-described embodiment (each of the reciprocating engines having two working spaces). The first working space of each piston engine acts as a compression chamber, whereas the second working space of each piston engine acts as an expansion chamber. The reciprocating engines are interconnected in a ring-serially (i.e., series) manner by each of the compression chambers of a reciprocating engine being in fluid communication with the expansion chamber of the reciprocating engine following a series connection via a thermal exchange device. The thermal exchanging apparatuses are similar in structure and operation to the above-described double-reciprocating heat exchanging apparatus, wherein each of the thermo-exchanging apparatuses successively provide a cooling means (for cooling the working medium), a regenerator (or heat buffer) in the direction from the respective compression chamber to the respective expansion chamber a heat exchanger (for exchanging heat with the working medium).

According to this aspect of the invention, compression of the working fluid in a compression chamber of a reciprocating engine causes expansion of the working fluid into the connected expansion chamber of the subsequent reciprocating engine. The interconnection of several piston machines allows an increase in performance over piston engines with only a single piston; In addition, it has been found that the cyclic series circuit according to the invention effects a self-synchronization of the multi-piston machine, ie. H. the optimum phase angles (in terms of the efficiency of the multi-piston machine) between compression and expansion are set automatically.

In the case of serial interconnection of N reciprocating engines, a phase shift of 2π / N in each case between the oscillatory movements of the liquid pistons of two reciprocating piston machines succeeding in series is realized. It can, for. B. be provided to connect three or four piston machines serially and cyclically, wherein the phase shift between the stroke of a liquid piston and the lifting movement of the adjacent liquid piston is 120 degrees or 90 degrees. In the formation of the multi-piston engine as an engine, the electrical work can be tapped directly as multi-phase voltage or multi-phase current (with N phases); whereas in the training as a heat pump, the multi-piston machine can be controlled or acted upon directly with multi-phase current. With regard to compatibility with standard electric power supply networks which provide three-phase alternating current, the design of the three-piston multi-piston machine is advantageous. The electrical control is preferably carried out with one of the resonant frequency or natural frequency of the multi-piston arrangement corresponding AC voltage frequency.

According to further aspects of the invention, there is provided a heat pump and a power generating device including a reciprocating engine according to any of the embodiments described above.

The invention will be described below with reference to embodiments with reference to the 1 to 7 illustrated, wherein the same or similar features are provided with the same reference numerals; Here are shown schematically:

1A an illustration of a piston engine according to an embodiment of the invention;

1B a perspective view of the electromechanical transducer of the piston engine according to 1 ;

2 an illustration of a double-acting piston engine according to an embodiment of the invention;

3A a double-piston engine according to an embodiment of the invention with a barrier fluid;

3B a double-piston engine according to an embodiment of the invention with a pulse tube;

4 a multi-piston machine according to an embodiment of the invention with three single-piston engines;

5 a representation of a working space with a valve assembly and a porous filling structure;

6A a compression cooling device having a piston engine functioning as a compressor;

6B a Joule-Thomson cooling device with a piston engine functioning as a compressor; and

7 a Rankine engine with a piston engine functioning as a compressor.

1A illustrates a piston engine 1 according to an embodiment, wherein the piston engine has a working space 3 in which a gaseous working medium 5 the piston engine 1 is included. The piston engine 1 also has a liquid piston 7 from an electrically conductive liquid. The liquid piston or the liquid 7 is in one to the work space 3 adjacent canal 9 held so that they are in the channel 9 can oscillate back and forth along the channel longitudinal direction (in the 1A and 1B is the direction of movement of the liquid through the double arrow 10 illustrates and runs within the channel 9 parallel to the y-direction of the in 1A and 1B represented xyz coordinate system) and in the adjacent work space 3 can flow in and out of it, so that the volume of the working space 3 according to the movement or according to the respective position of the liquid piston 7 varied. According to the embodiment according to 1 forms the end face 11 of the piston 7 a boundary surface of the working space volume 3 and is in direct contact with the working medium 5 ,

The piston engine 1 also indicates (see also 1B ) a magnet 13 on, wherein the magnet according to 1B as a permanent magnet 13 is trained. The magnet 13 is arranged such that the magnetic field generated by it 15 at the location of the liquid piston 7 is oriented perpendicular to the direction of movement (y-direction) of the liquid piston. According to 1B becomes the magnetic field generated by the magnet 15 for this purpose by means of a magnetic circuit 17 made of a soft magnetic material (eg iron) bundled and guided so that it is at the location of the liquid piston 7 or within the channel 9 (substantially) perpendicular to the channel longitudinal direction or flow direction 10 the liquid 7 is oriented, the field lines of the magnetic field 15 according to the 1A and 1B within the channel 9 (essentially) pointing in negative z-direction.

Furthermore, the piston engine 1 two electrodes 19 . 21 on, in direct electrical contact with the liquid 7 stand. The electrodes 19 . 21 are in one with respect to both the direction of flow 10 (ie, the y-direction) as well as the magnetic field direction 15 at the location of the piston (ie, the z-direction) perpendicular to each other (ie, the electrodes 19 . 21 are spaced apart along the x-direction) and each form a portion of the boundary wall of the channel 9 ,

The piston engine 1 has a control device (not shown), by means of which the piston engine 1 can be selectively switched to a motor mode or a generator mode. In the motor mode, the two electrodes 19 . 21 subjected to an (external) periodic alternating voltage, whereby the liquid piston 7 with an oscillation frequency corresponding to the frequency of the AC voltage in the channel 9 is moved back and forth and thus the free volume of the working space 3 periodically from the piston 7 is varied. In the engine mode, the liquid piston 7 z. B. act as a displacer for the working fluid (and this z., Periodically compress and expand, or periodically push out of the working space and suck into the workspace) and thus z. B. drive a connected thermodynamic cycle.

In generator mode, the workspace becomes 3 subjected to a periodic pressure variation in a known manner for pV machines, wherein by means of the pressure variation of the liquid piston 7 is placed in a periodic oscillating motion and - due to the effect of the Lorentz force on the moving electric charges of the liquid piston 7 in the magnetic field 15 - an AC voltage between the electrodes 19 . 21 is generated and can be tapped.

The pressure variation can z. B. by means provided therefor (in the 1A . 1B not shown) by alternately heating and cooling a closed working medium volume or by alternately introducing working fluid into the working space 3 and omitting of working medium from the working space 3 be caused.

2 illustrates a piston engine 23 according to a further embodiment, which differs from that in the 1A and 1B illustrated piston engine 1 this distinguishes that the piston engine 23 is designed as a double-acting piston engine, wherein at each of the two end faces 11 . 11 ' of the liquid piston 7 a working chamber 3 is connected. A reduction in the volume of one / of the workrooms or working chambers 3 due to a corresponding movement of the liquid piston 7 thus always goes with an increase in the volume of the other working chamber 3 associated.

3A illustrates a twin-piston engine 25 according to an embodiment which works according to the alpha-Stirling principle of operation. The double piston engine 25 has a first piston engine 27 that as a compression pv machine 27 acts, and a second piston engine 29 acting as an expansion pV machine. The compression machine 27 has a workspace 3 on, the expansion machine 29 has a workspace 3 ' on. Each of the two piston engines 27 . 29 has an associated electromechanical transducer with a liquid piston 7 , a magnet (in 3A not shown) and a magnetic circuit 17 , and two electrodes 19 . 21 as above with respect to the 1A and 1B described on.

The workroom 3 the compression machine 27 is about a thermal exchange device 31 in fluid communication with the working space 3 ' the expansion machine 29 , The thermal exchange device 31 points - in the direction of the work space 3 the compression machine 27 to the workroom 3 ' the expansion machine 29 towards - consecutively a cooling device 33 , a regenerator 35 and a heat exchanger 37 on.

During a compression movement of the piston 7 the compression machine 27 becomes the working medium 5 from the workroom 3 the compression machine 27 in the workroom 3 ' the expansion machine 29 crowded (and vice versa); the working medium 5 the thermal exchange device 31 flows through. The cooling device 33 is for cooling the working medium flowing therethrough 5 educated. The regenerator 35 is for temporarily storing the thermal energy of the working medium flowing through it in one direction 5 and delivering the stored thermal energy to the working medium passing therethrough in the other direction 5 educated. For example, the regenerator 35 for temporarily storing the thermal energy through it in the direction of the expansion machine 29 to the compression machine 27 towards working medium 5 and delivering the stored thermal energy to it through it in the direction of the compression engine 27 to the expansion machine 29 towards working medium 5 Act.

In the execution of the double piston engine 25 as an engine or power generating device, the heat exchanger functions 37 as a heater for heating the working medium flowing therethrough 5 , wherein the thermal energy z. B. from the exhaust heat of a motor vehicle. In the execution of the double piston engine 25 as heat pump or chiller the heat exchanger acts 37 as a cold heat exchanger or as a source of cold, wherein the working medium flowing through 5 can absorb thermal energy and thus acts as a cooling.

The realization of the thermodynamic Stirling cycle takes place both in the embodiment as an engine and as a heat pump by means of mutually phase-shifted electrical control of the electromechanical converter of the two pV machines 27 . 29 (ie admission of the respective electrode pairs of the pV machines 27 and 29 with an external electrical AC voltage). The compression machine 27 takes up (in total) electrical work, ie acts as a motor, and the expansion machine 29 gives (in total) electrical work, ie acts as a generator. When running as an engine is that of the expansion engine 29 delivered electrical work greater than that of the compression machine 27 recorded electrical work, wherein the heat exchanger acting as a heater 37 supplied thermal energy is converted into electrical energy. In the version as heat pump is that of the expansion machine 29 delivered electrical work smaller than that of the compression machine 27 recorded electrical work, with application of electrical energy of the heat exchanger 37 is cooled.

According to 3A is the liquid piston 7 the expansion machine 29 by means of a thermal insulation layer 39 in the form of a barrier liquid layer thermally from the working medium 5 and the heat exchanger 37 separated or decoupled. By means of the thermal insulation layer 39 is a heat exchange between the working medium 5 (or heat exchanger 37 ) and the liquid piston 7 effectively suppressed, so that associated thermal losses are effectively prevented. For example, when using the double-piston engine 25 as an engine through the insulation layer 39 a heating of the liquid piston 7 and a concomitant loss of performance prevented (By such a heating would be part of the heat exchanger - acting as a heater - 37 supplied thermal energy is no longer to perform expansion work and thus no longer to generate electrical energy in the expansion machine 29 be available, whereby the efficiency would be reduced accordingly, an analogous mode of action results when using the double-piston engine 25 as a heat pump). Additionally or alternatively it can be provided, the liquid piston 7 on the side of the compression machine 27 by means of a thermal insulation layer of the working space 3 (or the radiator 33 ) decouple thermally.

3B illustrates a twin-piston engine 41 according to another embodiment, which is designed as a pulse tube machine. The execution according to 3B differs from the design according to 3A in that instead of the barrier fluid layer 39 a compressible gas column 43 in a pulse tube 45 is provided as a thermal insulation layer. The gas column 43 may for example consist of the same material or medium as the working medium 5 ,

4 illustrates a multi-piston machine 47 according to an embodiment, wherein the multi-piston engine 47 several, here: three, double-acting single piston machines 23 . 23 ' . 23 '' having. Each of the three piston engines 23 . 23 ' . 23 '' has an associated electromechanical transducer with a liquid piston 7 , a magnet (in 4 not shown) with a magnetic circuit 17 , and two electrodes 19 . 21 as above with respect to the 1A and 1B described on (in 4 merely exemplified by the example of the piston engine 23 marked) and two workrooms or chambers 3 . 3 '' , where respectively the work space 3 as an expansion chamber and the work space 3 '' act as a compression chamber. The piston engines 23 . 23 ' and 23 ' 'are connected in a ring-shaped series, each by the compression chamber 3 '' a piston engine via a thermal exchange device 31 with the expansion chamber 3 the piston machine following in the series connection is in fluid connection. Each of the thermal exchangers 31 is similar in construction and principle of action above with respect to the 3A described thermal exchange device 31 and points - in the direction of the compression chamber 3 '' a piston engine to the expansion chamber 3 '' the following piston machine - consecutively a cooling device 33 , a regenerator 35 and a heat exchanger 37 on.

The multi-piston machine 47 can be analogous to those with respect to the 3A and 3B described double piston engines operated as an engine or as a heat pump or used, wherein in each case a reduction of the free volume of the compression chamber 3 '' a piston engine to increase the free volume of the expansion chamber 3 the subsequent piston engine leads. The control of the multi-piston machine 47 with three pistons by means of acting on the electrode pairs of the reciprocating engines 23 . 23 ' . 23 '' with corresponding alternating voltages, wherein the phases of the alternating voltages of successive pairs of electrodes are each shifted by 2π / 3 or 120 degrees to each other.

When using the multi-piston machine 47 The heat exchangers function as engines 37 (as related to 3A each described as a heater for heating the working medium flowing therethrough 5 ; in the embodiment as a heat pump or chiller, the heat exchangers function 37 each as a cold heat exchanger or as a source of cold, wherein the working medium flowing through 5 absorbs thermal energy and thus acts as a cooling. When used as an engine, the electrical work received by the electromagnetic transducers is less than the electrical work delivered to them, and the electrical work delivered can advantageously be picked up directly as a multi-phase voltage / current. When used as a heat pump, the electrical work taken up by the electromagnetic transducers is greater than the electrical work delivered to them, and the pairs of electrodes can be driven directly by a multiphase (here: three-phase) voltage.

In the embodiments according to the 3A . 3B and 4 are thermodynamic cycles with completed working medium volumes realized. However, it can also be provided to realize thermodynamic cycle processes by means of periodically introducing working medium into a working space and discharging it from the same.

5 Illustrates in this regard as a detail view of a section of a working space 3 with an inlet valve 49 , an exhaust valve 51 and one to the workroom 3 adjacent canal 9 , The channel 9 is with an open-pored filling structure 53 filled. The electrically conductive liquid of the liquid piston 7 is by means of a thermal insulation layer in the form of a barrier liquid 39 from the workroom 3 (or the working medium 5 ) thermally decoupled. By means of the inlet valve 49 and the exhaust valve 51 can be working medium 5 in the workroom 3 get in or out of the same and thus a pressurization or pressure relief of the working space 3 be effected. The electrical control of the piston engine also takes place in this case by means of Subjecting two electrodes (not shown) with an alternating voltage, wherein the electrical reversal or Spannungsumpolung done either with the resonant frequency of the piston system or by detecting the achievement of a predetermined reversing position (at which the direction of movement of the liquid piston 7 should be reversed) by means of two correspondingly positioned electrical contactor 55 . 57 , The control of the valves 49 . 51 can either be self-synchronizing or also via an electrical contact.

The 6A . 6B and 7 illustrate the realization of thermodynamic cycles with valve-controlled machines with valve arrangements analogous to 5 with an inlet valve 49 and an exhaust valve 51 ,

6A illustrates a compression cooling device 59 with one as a compressor 61 functioning piston engine 61 according to one embodiment. The piston engine 61 is analogous to that with reference to the 1A and 1B described piston machine 1 formed and has an inlet valve 49 and an exhaust valve 51 for the exchange of working medium 5 with the connected cooling circuit. The piston engine 61 acts by applying the two electrodes 19 . 21 with an external AC electrical voltage as a compressor 61 for compacting the working medium 5 , The connected cooling circuit points - in the direction of the exhaust valve 51 to the inlet valve 49 towards - a condensation cooler 63 for condensing the compressed working medium 5 , a relaxation device 65 (For example, a throttle valve) and acting as a heat exchanger evaporator 67 for evaporation of the working medium 5 taking up thermal energy (ie cooling). The relaxed working medium 5 is via the inlet valve 49 back to the compressor 61 fed.

6B illustrates a cooling device operating according to the Joule-Thomson effect 69 with a - analogous to the piston engine 61 according to 6A - as a compressor 61 functioning piston engine 61 according to one embodiment. The connected cooling circuit points - in the direction of the exhaust valve 51 to the inlet valve 49 out - an aftercooler 71 for cooling the compressed working medium 5 , a recuperator 73 for further cooling of the working medium 5 , a relaxation device 65 and an evaporator functioning as a heat exchanger 67 on. The relaxed working medium 5 is via the inlet valve 49 back to the compressor 61 fed. That of the exhaust valve 51 coming working medium 5 is either already in the aftercooler 71 or subsequently in the recuperator 73 condensed. The recuperator 73 serves to transfer residual refrigeration from the evaporated working medium 5 on the working medium to be evaporated 5 ,

7 illustrates a machine operating according to the Rankine cycle 75 (so-called "Rankine machine") with a piston machine 77 according to one embodiment. The piston engine 77 is analogous to that with reference to the 1A and 1B described piston machine 1 formed and has an inlet valve 49 and an exhaust valve 51 for the exchange of working medium 5 with the connected cooling circuit. The connected thermal circuit points - in the direction of the exhaust valve 51 to the inlet valve 49 towards - a condensation heat exchanger 79 , a condensate pump 81 (which has an inlet valve 49 ' and an exhaust valve 51 ' connected) and acting as an evaporator or superheater heat exchanger 83 on. The output of the heat exchanger 83 is with the inlet valve 49 connected. The control of the valves 49 . 51 can also be done here either self-synchronizing or via an electrical contact.

When using the Rankine machine 75 as an engine becomes the working medium 5 by means of the condensate pump 81 pressurized (the condensate pump 81 z. B. may also be a piston engine according to one embodiment), the working medium 5 is in the heat exchanger 83 - z. B. using the exhaust heat of a vehicle - heated and expanded under the drive of the piston engine 77 , wherein the kinetic energy of the liquid piston 7 via the electromechanical transducer is converted into electrical energy, passing through the two electrodes 19 . 21 can be tapped. Subsequently, the working medium 5 via the outlet valve 51 discharged and in the condensation heat exchanger 79 condensed.

When using the Rankine machine 75 as a heat pump, the liquid piston 7 the piston engine 77 driven by application of electrical energy and acts as a compressor for compressing the working medium; In this case, the heat exchanger acts 83 as a cold heat exchanger or cold source.

The piston machines according to the invention or pV machines with electromechanical drive or output can be used as compression and expansion machines in power, heat and refrigeration cycle processes. They can be provided in particular for input and / or output in small, high-speed machines, which z. B. as a prime mover or range extender for motor vehicles with hybrid drive (with an electric drive), for exhaust heat recovery in motor vehicles, for mobile or stationary uninterruptible power supply units (eg. Emergency generators), as a mini compressor z. B. in mobile and stationary household refrigerators or for (mixture) Joule-Thomson cryocooler, and as a pressure wave machines in regenerative cryogenic small refrigeration machines such. B. Stirling and pulse tube coolers can be used.

LIST OF REFERENCE NUMBERS

1

 piston engine

3, 3 ', 3' '

 working space

5

 working medium

7

 liquid pistons

9

 channel

10

 Direction of movement of the liquid piston

11, 11 '

 Face of the liquid piston

13

 magnet

15

 magnetic field

17

 magnetic circle

19, 21

 electrodes

23, 23 ', 23' '

 double-acting piston machine

25

 alpha-Stirling double-piston engine

27

 Compression pv machine / compression machine

29

 Expansion pv machine / expansion machine

31

 Thermotauschvorrichutng

33

 cooling device

35

 regenerator

37

 heat exchangers

39

 thermal insulation layer

41

 Pulse tube double piston engine

43

 gas column

45

 pulse tube

47

 Multi-piston engine

49, 49 '

 intake valve

51, 51 '

 outlet valve

53

 open-pore filling structure

55, 57

 electrical contactors

59

 Compression Cooler

61

 Compressor piston engine

63

 condensor

65

 relief device

67

 Evaporator heat exchanger

69

 Joule-Thomson cooler

71

 aftercooler

73

 recuperator

75

 Rankine machine

77

 piston engine

79

 Condensation heat exchanger

81

 condensate pump

83

 heat exchangers

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 7520133 B2 [0003]
• DE 102008050655 A1 [0004]

Claims (11)

Cyclic piston engine ( 1 . 23 ), comprising: - a work space ( 3 ) for recording a working medium ( 5 ), - a liquid piston ( 7 ) of an electrically conductive liquid, wherein the liquid piston in an adjacent to the working space channel ( 9 ) is movably arranged such that the volume of the working space varies according to the position of the liquid piston, - a magnet ( 13 ) for generating a magnetic field ( 15 ), which is designed and arranged such that the magnetic field at the location of the liquid piston ( 7 ) one perpendicular to the direction of movement ( 10 ) of the liquid piston oriented portion, and - two electrodes ( 19 . 21 ) in electrical contact with the liquid piston ( 7 ) are arranged at a distance to each other, wherein the distance both with respect to the direction of movement ( 10 ) of the liquid piston vertical portion as well as one with respect to the orientation of the magnetic field ( 15 ) has a vertical portion at the location of the liquid piston. Piston engine according to claim 1, wherein the liquid piston ( 7 ) thermally from the working medium ( 5 ) is isolated. Piston engine according to claim 2, wherein the liquid piston ( 7 ) by means of a thermal insulation layer ( 39 ) thermally from the working medium ( 5 ) is isolated. Piston engine according to one of claims 1 to 3, wherein the piston engine for applying the two electrodes ( 19 . 21 ) is formed with a periodic alternating voltage, wherein the liquid piston ( 7 ) is periodically reciprocated by means of the alternating voltage and the volume of the working space ( 3 ) varies according to the movement of the liquid piston. Piston engine according to one of claims 1 to 4, wherein the piston engine for alternately pressurizing and depressurizing the working space ( 3 ), wherein the volume of the working space varies periodically according to the pressure variation and the liquid piston ( 7 ) is reciprocated by means of the variation of the working space volume. Piston engine according to one of claims 1 to 5, wherein the working space ( 3 ) and / or the channel ( 9 ) at least partially with a porous, open-pored material ( 53 ) is filled. Piston engine according to one of claims 1 to 6, wherein the piston engine ( 23 ) two workrooms ( 3 ), wherein the liquid piston ( 7 ) is arranged such that it with its first end face ( 11 ) to one working space and with its other end face ( 11 ' ) adjacent to the other working space. Double piston machine ( 25 . 41 ) with a first ( 27 ) and a second ( 29 ) Piston engine according to one of claims 1 to 7, wherein: - the first piston engine ( 27 ) a work space ( 3 ) and the second piston machine a working space ( 3 ' ), and - the working space ( 3 ) of the first piston engine ( 27 ) via a thermal exchange device ( 31 ) in fluid communication with the working space ( 3 ' ) of the second piston engine ( 29 ), wherein - the thermal exchange device ( 31 ) in the direction of the working space ( 3 ) of the first piston engine ( 27 ) to the workspace ( 3 ' ) of the second piston engine ( 29 ) in succession a cooling device ( 33 ), a regenerator ( 35 ) and a heat exchanger ( 37 ) having. Multi-piston machine ( 47 ) with a plurality of piston engines according to claim 7, wherein: - each of the piston engines ( 23 . 23 ' . 23 '' ) acting as a compression chamber first working space ( 3 '' ) and a second working space acting as an expansion chamber ( 3 ), wherein - the piston engines ( 23 . 23 ' . 23 '' ) are serially connected in series, each by the compression chamber ( 3 '' ) of a piston engine via a thermal exchange device ( 31 ) in fluid communication with the expansion chamber ( 3 ) of the following piston engine, and wherein - each of the thermal exchange devices ( 31 ) in the direction of the compression chamber ( 3 '' ) to the expansion chamber ( 3 ) in succession a cooling device ( 33 ), a regenerator ( 35 ) and a heat exchanger ( 37 ) having. Heat pump with a piston engine according to one of claims 1 to 9. Power generating device with a piston engine according to one of claims 1 to 9.

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