Free-piston device and method for controlling and/or regulating a free-piston device

The present invention has at least one piston accommodating device and at least one having a second piston surface that moves linearly within the corresponding piston accommodating device and is oriented away from the first piston surface and the first piston surface. A free piston assembly including one piston device and an expansion space formed in the piston accommodating device and defined by the surface of the first piston, wherein the piston device expands in the expansion space. It relates to a free piston assembly arranged to be driven by the action of a medium.

Further, the present invention relates to a method for controlling a free piston assembly including a piston accommodating device, a piston device that moves linearly in the piston accommodating device, and a restoration space.

For example, a free piston assembly can be used to partially convert chemical energy into mechanical energy, the kinetic energy of a piston device, during the combustion process, and then at least this mechanical energy can be converted using a linear drive. It can be partially converted into electrical energy. By arranging the piston movement in the form of free piston movement, it is possible to realize a purely linear movement of the piston without the need to provide a crankshaft.

A device of this nature can be used, for example, as part of a hybrid drive of an automobile, especially in combination with the concept of a series hybrid arrangement. These devices can also be used as compact current generators to generate electricity or in combination with stationary applications such as engine-based cogeneration systems.

Free piston assemblies are known from, for example, GB 854 255 and DE 22 17 194 C3.

US 6,199,519 B1, DE 31 03 432 A1, East German Patent Specification 113,593, and DE 43 44 915 A1, or P. van Barrigan's paper "Advanced internal combustion engine research" in "Proceedings of the 2000 DOE of Hydrogene Program Review" Therefore, a combustion device equipped with a generator is also known.

From DE 102 19 549 B4, free piston assemblies including electric linear drives are known. The free-piston assembly includes at least one piston accommodating device and at least one piston accommodating device arranged for linear motion within the piston accommodating device. Here, the piston device includes a rotor assembly, and the stator assembly is arranged in the piston accommodating device. At least one piston device is arranged to be driven by the action of a medium that expands in the expansion chamber, and the piston stroke is varied by a linear drive so that the dead center in the motion of the piston device can be defined. It is adapted to.

WO 01/45977 A2 describes another free piston assembly that includes an electric linear drive.

From EP 1 398 863 A1, the first displacement chamber in which the piston of at least one piston device on which the medium acts is movable and the second displacement chamber in which the rotor assembly associated with the piston is movable are separate. Free piston assemblies, which are chambers, are known.

From DE 197 81 913 T1, a method of controlling the motion of a linear generator is known. This linear generator is driven by an internal combustion engine in which two opposing pistons are aligned along a common axis. During the periodic reciprocating motion of the generator, current consumption is controlled so that effective resistance to the generator is generated approximately proportionally, at least within the central stroke range of the generator's velocity of motion. A pressure sensor is provided in the combustion chamber, and when a predetermined pressure is reached, the control unit triggers a device that ignites the mixture supplied to the combustion chamber.

From DE 10 2004 062 440 B4, free piston assemblies with electric linear drives are known. This free-piston assembly includes a restoration chamber containing gas. At least one pressure sensor is provided in the restoration chamber, which allows the position and / or velocity of the piston device to be determined from the measurement of the pressure of the gas in the restoration chamber. Thus, using the measured pressure, for example, with respect to the injection of fuel into the expansion chamber and the ignition point of fuel in the expansion chamber, and / or with respect to the valve located on the expansion chamber, the free piston assembly. Can be controlled and / or adjusted.

From US 5,002,020, hybrid engines with reciprocating pistons and electromagnetic transducers are known for control / regulation and power output purposes.

From WO 2008/037980 A2, which has not been released in advance, a free-piston engine having a double-acting arrangement configuration is known. One piston undergoes a conventional internal combustion cycle on one side and a steam expansion cycle on the other side.

<p><patcit num="1"><text>GB 854 255</text></patcit><patcit num="2"><text>DE 22 17 194 C3 (US 4,154,200)</text></patcit><patcit num="3"><text>US 6,199,519 B1</text></patcit><patcit num="4"><text>DE 31 03 432 A1</text></patcit><patcit num="5"><text>East Germany DD 113,593</text></patcit><patcit num="6"><text>DE 43 44 915 A1</text></patcit><patcit num="7"><text>DE 102 19 549 B4 (US 2005/0081804 A1)</text></patcit><patcit num="8"><text>WO 01/45977 A2</text></patcit><patcit num="9"><text>EP 1 398 863 A1</text></patcit><patcit num="10"><text>DE 197 81 913 T1 (US 6,181,110 B1)</text></patcit><patcit num="11"><text>DE 10 2004 062 440 B4</text></patcit><patcit num="12"><text>US 5,002,020</text></patcit><patcit num="13"><text>WO 03/091556 A1 (US 2005/0081804 A1)</text></patcit><patcit num="14"><text>DE 102 42 141 A1</text></patcit><patcit num="15"><text>WO 2008/037980 A2</text></patcit><patcit num="16"><text>US 5,287,827 A</text></patcit><patcit num="17"><text>US 4,454,426 A</text></patcit><patcit num="18"><text>WO 2007/147789 A1 (US 2009/0101005 A1)</text></patcit></p>

<p><nplcit num="1"><text>"ADVANCED INTERNAL COMBUSTION ENGINE RESEARCH", by Peter van Blarigan, Proceedings of the 2000 DOE Hydrogen Program Review</text></nplcit></p>

<p> It is an object of the present invention to provide a free piston assembly of the type described above, which is feasible in a simple manner and has a compact configuration.</p>

<p> According to the present invention, in the above-mentioned free piston assembly, the restoration space arranged in the at least one piston accommodating device is defined by the surface of the second piston, and the restoration space is at least one. This is achieved by fluidly connecting to one preload chamber.</p><p> By using the solution according to the present invention, the length of the piston accommodating device can be optimized and used.</p><p> In particular, for example, if the distance between the expansion space and the restoration space is approximately the same as the corresponding thickness of the piston, this distance can be minimized.</p><p> Further, it is possible to construct a free piston assembly including a drive unit and an application unit in a modular manner. In the case of the solution according to the present invention, the active element can be guided in a simple manner from the rear end of the driving unit. As a result, applications such as compressors and linear drives can be modularly coupled. This allows several applications to be coupled using series and / or parallel couplers.</p><p> In the case of the solution according to the present invention, it is possible to use blow-by from the expansion space to the restoration space. When blow-by occurs, gas from the expansion space enters the restoration space due to leakage between the piston device and the piston accommodating device. When the restoration space is in the form of a gas spring chamber, the blow-by can maintain the gas pressure in the restoration space, or use the blow-by to reduce the pressure loss in the restoration space. Can be done. If desired, the blow-by can be set in a defined manner by utilizing a defined setting for the amount of "leakage".</p><p> The restoration space is fluidly connected to at least one preload chamber. Thus, for example, it is possible to control or adjust the gas pressure in the restored space and hence the elastic properties of the restored space.</p><p> It is convenient that the expansion space and the restoration space are arranged linearly in the front-rear direction. As a result, a compact structure with the minimum longitudinal dimension can be obtained.</p><p> In particular, the expansion space and the restoration space are separated by the piston of the piston device. Here, the piston includes the surface of the first piston and the surface of the second piston. As a result, the distance between the expansion space and the restoration space is minimized.</p><p> For the same reason, it is convenient that the internal length of the piston accommodating device consists of the length of the expansion space, the distance between the surface of the first piston and the surface of the second piston, and the length of the restoration space.</p><p> A compact structure can be realized when the distance between the surface of the first piston and the surface of the second piston is up to 30% of the total internal length of the piston accommodating device.</p><p> It is particularly advantageous that the at least one piston containment device includes a side surface in which at least one linearly movable active element connected to the piston device is guided outward. Mechanical energy can be "extracted" from the active element. That is, one or more applications can be linked to the active element. Thereby, it is possible to realize a modular structure including a free piston assembly including a drive unit and an application unit, particularly a replaceable application unit.</p><p> In particular, the at least one active element is a piston rod.</p><p> It is conceivable that the side surface is an end surface oriented in a direction orthogonal to the operating direction of the piston device. Therefore, the connecting side of the drive unit can be made available in a simple manner .</p><p> In particular, a wall facing the surface of the second piston is arranged on the side surface. As a result, a device for connecting the mechanical energy to the outside is provided in a simple manner.</p><p> Furthermore, it is convenient for this wall to delineate the restored space. The restored space does not need to be equipped with a device for supplying fuel or the like to the restored space, and it is not necessary to remove exhaust gas from the restored space. This gives a simple structure. However, in principle, it is also possible to guide the active element to the outside from the wall demarcating the expansion space.</p><p> It is convenient for the wall to have an opening through which the at least one active element passes. In that case, the mechanical energy can be connected to the outside in a simple manner.</p><p> Further, it is advantageous that bearings for the at least one active element be placed on this wall. The bearing is, for example, a plain bearing for guiding the displacement of the active element. This can improve the overall support of the element.</p><p> It is conceivable that the lower portion of the at least one active element is guided through the restoration space. This provides a simple structure and provides a simple device for connecting the mechanical energy to the outside. However, as described above, in principle, it is also possible to guide the at least one active element through the expansion space.</p><p> It is particularly advantageous if the at least one active element includes a coupler for linking this active element to the application. In this way, the application can be mounted in a simple manner in order to utilize the mechanical energy from the drive unit.</p><p> It is convenient for the expansion space to have at least one inlet port associated with this expansion space. This allows fuel to be loaded using the inlet port or an expandable heat transfer medium.</p><p> In particular, a controllable valve is preferably located at the at least one inlet port so that the entry of fuel or the supply of the expandable heat transfer medium can be controlled.</p><p> When the expansion space has at least one outlet port associated with the expansion space, for example, exhaust gas generated from the combustion process can be removed from the expansion space, or the expanded heat transfer medium can be removed. It can be removed from this expansion space.</p><p> Therefore, it is convenient to have a (controllable) valve at the outlet port.</p><p> It is particularly convenient that the restoration space is a gas spring space in which the compressible medium is housed. The compressible medium (gas) is held under pressure in the gas spring space. Thereby, the reciprocating motion of the piston device can be created. Further, as described in WO 03/091556 A1, it is possible to control the motion of the piston device.</p><p> For example, it is convenient to provide a control unit for controlling the connection so that the pressure in the restoration space can be adjusted.</p><p> In one exemplary embodiment, the at least one preload chamber is connected to the restoration space by the end face of the piston accommodating device. As a result, the piston accommodating device and the preload chamber are linearly connected back and forth.</p><p> In principle, the at least one preload chamber can be arranged so as to be separated from the active element.</p><p> In another embodiment, the active element is guided through the at least one preload chamber.</p><p> At least one channel, including a first opening and a second opening, is arranged in the at least one active element, and the first opening and / or the second opening in the restoration space and / or in the preload space of the preload chamber. It is particularly advantageous if the position of is dependent on the position of at least one active element. This makes it possible to control the process of equalizing the pressure between the preload space and the restoration space in a time-dependent manner, for example, when there is no time-controlled valve from the outside. Therefore, it is no longer necessary to use, for example, a high pressure valve.</p><p> In particular, the preload chamber and the restoration space are fluidly connected to the channel at one or more positions of the piston device. This enables a pressure equalization process.</p><p> Here, the one or more positions may be located near the inversion point or the inversion point of the piston device. In that case, by appropriately configuring the channel and the opening, in principle, this position can be set to be an upper inversion point or a lower inversion point.</p><p> (At least) one application may be placed within the preload chamber. The preload space in the preload chamber can be used to regulate the pressure in the restoration space. A housing in which an application such as a linear drive is located can be used to form the preload chamber. This minimizes the overall length of the free-piston assembly and at the same time provides a compact way of construction.</p><p> For example, at least one linear drive may be connectable or connected to the piston device. The linear drive is, for example, in the form of a linear generator. In that case, an electric current can be generated. As described in WO 03/091556 A1, in principle, it is also possible to control the movement of the piston device by the linear drive.</p><p> The at least one linear drive includes a stator and an actuator connected to said at least one active element of the piston device. The piston device provides mechanical energy to generate an induced current.</p><p> For example, the at least one linear drive follows the piston accommodating device in a direction parallel to the operating direction of the piston device. Therefore, for example, the dimensions in the orthogonal direction can be reduced.</p><p> It is also possible that the at least one linear drive at least partially surrounds the at least one piston accommodating device and / or preload chamber. Therefore, the dimensions in the longitudinal direction can be kept small.</p><p> For example, at least one compressor can be connected to or can be connected to the piston device. For example, the compressor compresses the gas or liquid.</p><p> In particular, the piston rod of the at least one compressor is connected to the active element of the piston device.</p><p> Furthermore, an object of the present invention is to provide the above-mentioned kind of method that can be realized in a simple manner.</p><p> According to the present invention, an object of the present invention is to provide the restored space and preload in the free piston assembly including a piston accommodating device, a piston device that can move linearly in the piston accommodating device, and a restored space. The fluid connection with the space is opened and closed depending on the position of the piston device, one or more piston rods of the piston device are guided in the restoration space and the preload space, and the first opening and the first opening and the first. This is achieved by arranging at least one channel with two openings on the at least one piston rod.</p><p> The method according to the present invention has the advantages already described with respect to the apparatus according to the present invention.</p><p> In the case of the method according to the present invention, the pressure in the restoration space is automatically controlled by the position of the piston device. For example, the pressure in the preload space can be set as an operating point, and an automatic pressure equalization process can be performed. In that case, a high pressure valve for controlling the pressure in the restoration space is no longer needed. Further, since the control process is automatically performed depending on the position of the piston device, the control process timed from the outside is no longer necessary.</p><p> In particular, the first opening and the second opening are fluidly connected. Therefore, gas exchange can be performed via the channel.</p><p> In particular, there are one or more positions of the piston device, wherein the first opening is in the restoration space and the second opening is in the preload space. Thereby, the gas can be equalized between the restoration space and the preload space, and the pressure in the restoration space can be controlled particularly by this gas equalization process.</p><p> Further, it is convenient to have one or more positions of the piston device in which both the first opening and the second opening are installed either in the restoration space or in the preload space. In this case, the gas cannot be exchanged between the preload space and the restoration space.</p><p> In order to illustrate the invention in more detail, preferred embodiments considered in conjunction with the drawings are described below.</p>

<figref num="1">FIG. 6 is a schematic cross-sectional view of an exemplary first embodiment of the free piston assembly according to the present invention.</figref><figref num="2">The schematic of the 2nd Embodiment of the free piston assembly which concerns on this invention.</figref><figref num="3">The schematic of the 3rd Embodiment of the free piston assembly which concerns on this invention.</figref><figref num="4">The schematic of the 4th Embodiment of the free piston assembly which concerns on this invention.</figref><figref num="5">FIG. 5 is a schematic view of an exemplary fifth embodiment of a free piston assembly according to the present invention.</figref><figref num="6">FIG. 6 is a schematic view of an exemplary sixth embodiment of the free piston assembly according to the present invention.</figref><figref num="7">The schematic of the 7th Embodiment of the free piston assembly which concerns on this invention.</figref><figref num="8">Schematic of an exemplary eighth embodiment.</figref><figref num="9">Schematic of an exemplary ninth embodiment.</figref><figref num="10">Schematic of an exemplary tenth embodiment.</figref>

FIG. 1 shows an exemplary first embodiment of the free-piston assembly according to the present invention with reference to reference numeral 10. This embodiment includes a drive unit 12 and an application unit 14. The drive unit 12 makes mechanical energy available in the form of reciprocating motion of the active element 16. This mechanical energy can be utilized in application unit 14 by corresponding applications such as compressors and / or linear drives, as described below.

The drive unit 12 includes (at least) one piston accommodating device 18 (cylinder) in which the piston device 20 is arranged so that it can move linearly.

The piston accommodating device 18 has a piston space 22 in which the piston 24 of the piston device 20 can linearly move in one direction 26 from the other. One and the other direction 26 are parallel to the longitudinal axis 28 of the piston accommodating device 18.

The piston 24 has a first piston surface 30 and an opposing second piston surface 32. For example, the surface 30 of the first piston and the surface 32 of the second piston are parallel to each other. For example, in one embodiment, there is a piston 24, which is a solid material, between the first piston surface 30 and the second piston surface 32.

Separately, the piston 24 may include one or more cavities between the first piston surface 30 and the second piston surface 32. The cavities serve, for example, for the purpose of reducing mass and / or providing thermal decoupling. In principle, the cavity can also be used for internal cooling of the piston 24.

The piston space 22 is defined by the first end wall 34 on the first end face and by the second end wall 36 on the opposite second end face. The first end wall 34 and the second end wall 36 are oriented in a direction orthogonal to the longitudinal direction 28, and therefore are also oriented in a direction orthogonal to the motion direction 26.

Between the first end wall 34 and the surface 30 of the first piston, an expansion space 38 is installed in which the expansion medium can expand and exert a force on the piston 24.

A restoration space 40 in the form of, for example, a gas spring space is formed between the surface 32 of the second piston and the second end wall 36. Therefore, the compressible medium, particularly the gas, is housed in the restoration space 40. This compressible medium provides a spring-like return of the piston 24.

Separately or additionally, one or more mechanical spring elements 41 may be placed within the restoration space 40. At least one spring element 41 is linked to the piston 22 and is supported directly or via an intermediate on the second end wall 36.

The total volume of the piston chamber 22 is the sum of the volumes of the expansion space 38 and the restoration space 40 and the volume of the piston 24. The volume ratio of the expansion space 38 to the restoration space 40 depends on the position of the piston 24 of the piston device 20. The piston 24 is arranged and guided in the piston chamber 22 in such a way that the expansion space 38 and the restoration space 40 are sealed so as to be gastight with each other.

In principle, blow-by between the expansion space 38 and the restoration space 40 is possible due to the sealing tolerance. The fluid (particularly gas) entering the restoration space 40 from the expansion space 38 is used as a springy medium in the restoration space 40. Blow-by can be used within the restoration space 40 to maintain pressure or reduce pressure loss. As a result, in some situations, the free-piston assembly can be realized in a compact and inexpensive way, as it is possible to eliminate the need for a fixed pump to maintain the pressure in the restoration space 40.

The piston device 20 includes a piston rod 42 that sits on the piston 24 and is guided through the restoration space 40. The second end wall 36 includes an opening 44 through which the (gas-dense) piston rod 42 passes. In the process of linear motion of the piston in one and the other direction 26, a bearing device 46, for example in the form of a plain bearing, is placed in the opening 44 to support the piston rod 42 and thus the piston device 20.

In the exemplary embodiment shown in FIG. 1, the restoration space 40 is sealed relative to its periphery so that the compressible medium within the restoration space 40 cannot escape to the surroundings through the opening 44.

The piston rod 42 forms the active element 16. A coupler 48 is located on the piston rod 42, preferably at its outer end, to which the coupler 48 is coupled with an application to extract available mechanical energy.

The second end wall 36 forms the outer end of the drive unit 12 or is installed near the outer front end of the drive unit 12. In that case, the application can be subsequently attached to the drive unit 12 in the longitudinal direction 18. These applications can be connected to the drive unit 12 back and forth to some extent.

The restoration space 40 is formed in the same piston accommodating device 18 as the expansion space 38. The piston 24 forms a separating device for the expansion space 38 and the restoration space 40.

For example, the surface 30 of the first piston is circular. For example, the surface 32 of the second piston is circular.

One or more application units 14 are modularly connected to the drive unit 12, and one or more application units 14 use the mechanical energy provided by the drive unit 12. ..

The expansion space 38 and the restoration space 40 are formed in the same piston chamber. As a result, the piston accommodating device 18 can be compactly configured with relatively small longitudinal dimensions in the longitudinal axis 28 direction.

The expanding gas in the expansion space 38 oscillates and displaces the active element 16 (in one and the other direction 26).

In one embodiment, the expansion medium in the expansion space 38 is in the form of a flammable gas. Within the piston accommodating device 18, a (at least one) inlet port 50 for the expansion space 38 is arranged through which a fuel or fuel-oxidizer mixture can be introduced into the expansion space 38. In principle, it is possible to provide separate inlet ports for fuel and oxidizer. The inlet port 50 is arranged with a valve 52, especially a controllable valve. The amount of fuel or fuel-oxidant mixture supplied can be controlled by the valve 52.

Further, within the piston accommodating device 18, one (at least) one outlet port 54 from which the medium can be removed from the expansion space 38 is arranged. In particular, the exhaust gas can be removed from the expansion space 38.

A valve 56 is located at the outlet port 54 to allow control of the removal process.

An igniter 57 for igniting a fuel-oxidizer mixture can be associated with an expansion space 38. In principle, a self-igniting medium can also be used.

In the modification of this embodiment, the expansion medium in the expansion space 38 is a heat transfer medium generated or heated outside the expansion space 38. Since this heat transfer medium can expand in the expansion space 38, this allows the piston 24 to perform its vibrating motion.

In this case, the inlet port 50 serves to connect the expandable heat transfer medium into the expansion space 38 in a controlled manner. The "expanded" heat transfer medium can be expelled through the outlet port 54.

For the purpose of measuring the pressure in the restoration space 40, the restoration chamber can have one or more pressure sensors 53 associated with this restoration chamber. One or more pressure sensors 53 are arranged, for example, on the second end wall 36.

In a similar manner, the expansion space 38 can have one or more pressure sensors 55 associated with this expansion space to help measure the pressure in the expansion space. One or more pressure sensors are specifically located on the first end wall 34.

Further, the expansion space 38 can have at least one injection valve 51 associated with the expansion space, for example, to which fuel is injected.

FIG. 2 shows an exemplary second embodiment of the free-piston assembly with reference to reference numeral 58. This embodiment is basically configured in the same manner as the first free piston assembly 10. Therefore, the same reference code is used for the same element.

Further, the restoration space 40 is associated with (at least) one preload chamber 60 including the preload space 62. The preload chamber 60 is arranged so as to be separated from the active element 16. For example, it is placed behind the end limited by the second end face 64. The preload space 62 is fluidly connected to the restoration space 40 by a controllable valve 66. The pressure of the gas spring device in the restoration space 40 can be adjusted, for example, by the preload chamber 60. In particular, this pressure can be controlled and thus adapted to the special mode of operation of the free-piston assembly 58.

In one embodiment, the pressure is controlled at bottom dead center of the gas spring device within the restoration space 40. At the bottom dead center (BDC) of the restoration space 40, the volume of the restoration space 40 is maximized, and the process of controlling / adjusting the pressure is the easiest.

The preload space 62 is fitted with a pump 67 that helps to apply pressure to the preload chamber 60.

For example, the preload chamber 60 can equalize the pressure loss in the restoration space 40.

FIG. 3 shows an exemplary third embodiment of the free-piston assembly according to the present invention with reference to reference numeral 68. This embodiment includes a piston accommodating device 70 having a first end face 72 and a second end face 74. The piston device 76, including the piston 78 and the piston rod 80, is linearly movable within the piston containment device 70. The piston rod 80 forms the active element 82, which allows mechanical vibration energy to be conducted to the application. At one end of the active element 82, a coupler 84 is placed for attachment to the application.

The piston accommodating device 70 includes an expansion space 86 and a restoration space 88, but the method and function of its configuration are basically the same as those described above.

A preload chamber 90 in which a preload space 92 is formed is arranged on the second end surface 74. The first end face 94 of the preload chamber 74 faces the second end face of the piston accommodating device 70, for example, is in contact with or overlaps the second end face. The second end face 96 faces away from the second end face 74 of the piston accommodating device 70.

The preload chamber 90 and the piston accommodating device 70 are arranged so as to be in front of and behind each other. The preload chamber 90 is in contact with the piston accommodating device 70 in parallel with the operating direction of the piston device 76.

In the second end face 96 of the preload chamber 90, the corresponding end wall is provided with an opening 98 through which the active element 82 is passed. In particular, a bearing device such as a slide bearing for supporting the active element 82 is arranged in the opening 98. The bearing device and active element 82 are sealed relative to the perimeter.

In the second end surface 74 of the piston accommodating device 70, the corresponding end wall 100 is provided with an opening 102 in which the active element 82 is similarly guided through. In particular, bearing devices such as plain bearings are arranged there. The opening 98 is installed between the restoration chamber 88 and the preload space 92 of the preload chamber. The opening 98 is sealed to the active element 82 so that gas exchange between the perimeter and the preload space 92 cannot be performed through the opening 98.

The preload chamber 90 includes one or more openings 104 through which the pressure in the preload space 92 can be controlled.

A channel 106 (at least one) is arranged on the active element 82, and the channel 106 includes a first opening 108 and a second opening 110 toward the outer surface of the active element 82. Gas can flow through this channel 106 through the first opening 108 and the second opening 110. Outside the channel 106, the active element 82 is made of a gas impermeable material.

The channel 106 acts as an "automatic valve" that allows or suppresses fluid exchange between the preload space 92 and the restoration chamber 88, depending on the position of the active element 82.

At the position of the active element 82 shown in FIG. 3, the second opening 110 is in the preload space 92 and the first opening 108 is in the restoration chamber 88. Therefore, it is possible to equalize the pressure between the preload space 92 and the restoration space 88. Therefore, for example, for the purpose of realizing the variable spring characteristics of the gas spring device in the restoration space 88, it is possible to control the pressure in the restoration space 88 by the pressure in the preload space 92.

This makes it possible to adjust the properties in a spatially defined manner (with respect to the position of the piston) and / or in a temporally defined manner. Thereby, basically, a specific spring rigidity can be set for each position of the piston and each time point.

The channel 106 forms a valve that does not need to be switched externally, and a "self-regulating" process is realized. Depending on the location of the first opening 108 and the second opening 110 (and the geometric dimensions of the channel 106), the first opening 108 is in the restoration chamber 88 and the second opening 110 is in the preload space 92. When it reaches, the pressure equalization process can be performed there. In that case, the high pressure valve for the restoration space 88 is unnecessary. Further, since the position of the active element 82 itself controls the pressure equalization process, it is not necessary to control the valve timing from the outside.

If both the first opening 108 and the second opening 110 are in the restoration space 88, or if both of them are in the preload space 92, the pressure equalization process cannot occur.

In the illustrated exemplary embodiment, pressure equalization occurs when the piston 78 is at or near the reversal point in the motion of the piston device 76. Thereby, depending on the channel 106 being configured with the first opening 108 and the second opening 110, the restoration space 88 and the restoration space 88 at or near the lower inversion point or the upper inversion point. It is possible to make a fluid connection with the preload space 92.

Due to the support of the active element 82 within the opening 98 and / or the opening 102, especially the sliding support, the piston 78 no longer has a guiding function. Therefore, the piston only needs to serve to effectively seal between the expansion space 86 and the restoration space 88.

FIG. 4 shows an exemplary fourth embodiment of the free-piston assembly according to the present invention as a whole with reference numeral 112. In this embodiment, the drive unit 114 as described with respect to FIG. 2 is realized. The active element 16 of the drive unit is connected to the actuator 116 of the linear drive via a coupler 48. The actuator 116 is reciprocally displaced by the active element 16 so as to be linear.

Actuator 116 moves in and / or creates a magnetic field, which is moved by actuator 116. Therefore, an induced current can be generated, especially in cooperation with an appropriate stator.

Actuator 116 carries a magnet device 120 that includes, for example, a permanent magnet 122 that is spaced apart from the longitudinal axis 118 and has alternating polarity in the longitudinal direction parallel to the longitudinal axis 118.

The drive unit 114 is fixedly arranged. This is shown by base 124 in FIG. The similarly fixed stator 126 cooperates with the actuator 116. The stator 126 includes, for example, winding 128. The magnet device 120 is moved relative to the stator 126 by the reciprocating motion of the active element 16 and by the reciprocating motion of the actuator 116 caused thereby. As a result, an electric current is induced and taken out. The corresponding linear drive 130 acts as a linear generator that produces current. Within the linear drive 130, the mechanical energy generated by the drive unit 114 can be converted into an electric current.

However, in principle, the linear drive 130 can also be used to control / adjust the piston device of the drive unit 114. This is described in WO 03/091556 A1, which is explicitly referenced.

The linear drive 130 is connected to the active element 16. Other types of applications may be linked in addition to or separately from this.

The actuator 116 may be provided with one or more electromagnets. The actuator may include a short winding. It is also possible for the actuator to carry a "passive" dentate structure made of a magnetically conductive material.

FIG. 5 shows an exemplary fifth embodiment with reference to reference numeral 132. Also in this embodiment, the drive unit 114 is provided. A compressor 134 is connected to the active element 16 of the drive unit. The compressor can serve to compress the gas or liquid and can be, for example, a compressor for a refrigerant, a hydraulic compressor, or a water compressor (eg, in the form of a pump).

The active element 16 is connected to a compressor piston 136 guided through the corresponding cylinder 138. The active element 16 is directly connected to the piston 136 or to the piston rod 140 seated on the piston 136. A compression chamber 144 is formed between the end wall 142 and the piston 140. Within this compression chamber 144 are one or more inlet ports 146, each having a control valve 148 seated therein. The medium to be compressed is arranged so that it is tethered in through the inlet port 146.

Further, one or more outlet ports 150, each having a control valve 152 seated therein, are seated within the end wall 142. The compressed medium can be removed through the exit port.

The compressor shown in FIG. 5 is a single-stage compressor in the sense that it includes only one compression chamber 144.

FIG. 6 shows an exemplary sixth embodiment with reference to reference numeral 154. Also in this embodiment, a drive unit 114 is provided, and the active element 16 of the drive unit is connected to the piston 156 of the compressor 158. Piston 156 is located in cylinder 160 closed by first end wall 162 and second end wall 164 (apart from inlet and outlet ports). A first compression chamber 166 and a second compression chamber 168 are formed in the cylinder 160. In this sense, the compressor 158 is a single-stage compressor. The medium can be compressed in both the first compression chamber 166 and the second compression chamber 168. As a result, it is possible to generate a corresponding compression process during both the forward and backward movements of the piston 156, thus achieving a dual effect. Pulsation can be reduced. The entire process can be optimized using different compression media. The space occupied by this structure can also be minimized.

One or more inlet ports and one or more inlet ports and one or more in the first compression chamber 166 and in the second compression chamber 168 to allow the medium to be compressed to enter and the compressed medium to be expelled. An exit port is provided.

The compressor 158 is connected in series (continuously) with the drive unit 114. Further, linear drives can be connected in series, which are constructed in a manner similar to, for example, the linear drive 130. For this purpose, the corresponding actuator 116 of this linear drive is connected to the piston rod 170, on which the piston 156 is seated. The piston rod 170 is connected to the active element 16.

It is also possible to operate several application units in parallel. In the equivalent circuit diagram, application units operating in parallel form a combination connected in series with the drive unit 12.

The active element 16 reciprocates linearly by the drive unit 114 of the free piston assembly 154. This motion is conducted to the piston rod 170 via the coupler and then to the actuator 116. The piston rod 170 activates the compressor 158, and the actuator 116 generates an electric current in the linear drive 130.

FIG. 7 shows an exemplary seventh embodiment of the free-piston assembly with reference to reference numeral 172. In this embodiment, a drive unit 174 corresponding to the drive unit according to FIG. 3 is provided. The corresponding active element 82 is coupled to the actuator 176 of the linear drive 178. The actuator 176 is, for example, cup-shaped and surrounds the preload chamber 90 and also partially surrounds the piston accommodating device 70. As a result, the longitudinal dimensions of the free piston assembly 172, including the linear drive 178, can be kept small. (In some situations, this increases the longitudinal dimension.)

The actuator 176 carries, for example, a magnet device 180. The magnet device is moved by the active element 82 with respect to the stationary stator 182. Therefore, an electric current can be generated.

According to the present invention, a free piston assembly capable of extracting mechanical energy from the drive unit is provided. Thus, this results in a modular structure to which applications such as, for example, one or more compressors and one or more linear drives can be coupled.

Further, an expansion space and a restoration space directly adjacent to each other are realized. These spaces are defined by the same piston by the opposing surfaces of the piston. Therefore, this results in a compact structure as far as the length is concerned.

FIG. 8 schematically illustrates an exemplary eighth embodiment of the free-piston assembly according to the present invention with reference to reference numeral 184. In this embodiment, the structure is essentially the same as that of the free piston assembly 10. The corresponding elements use the same reference code as the free-piston assembly 10. The piston 24 is guided in the piston accommodating device 186 including the first end wall 188 and the second end wall 190 facing the first end wall 188. A control valve 192 (at least one) is arranged on the second end wall 190 that demarcates the restoration space 40. For the free piston assembly 184, the restoration space 40 is a gas spring chamber. The remaining gas can be released from the restoration space 40 by the control valve 192.

The piston 24 is guided along the inner surface 194 of the piston accommodating device 186. A guide surface 196 for the piston 24 is provided by the peripheral surface of the piston facing the piston accommodating device 186. Basically, there is a leak between the guide surface 196 and the inner surface 194, allowing fluid, especially gas, to enter the restoration space 40 from the expansion space 38. This is indicated by arrow 198 in FIG.

If the pressure in the expansion space 38 is higher than the pressure in the restoration space 40, gas is pushed from the expansion space 38 to the restoration space 40 through such a leak. This is called blow-by. This blow-by can be used to maintain the pressure in the restoration space 40, which is in the form of a gas spring chamber, or can be used to reduce the pressure loss there. The remaining gas can be released from the restoration space 40 by the control valve 192.

In other respects, the free-piston assembly 186 functions in the same way as the free-piston assembly 10.

FIG. 9 schematically illustrates a ninth embodiment of the free-piston assembly according to the present invention with reference to reference numeral 202. In this embodiment, the drive unit 204 corresponding to the drive unit of the free piston assembly 184 is connected to the preload chamber 206. At least one control valve 192 is fluidly connected to the preload space 208 of the preload chamber 206. This allows at least one control valve 192 to be bidirectional, or a different unidirectional control valve to allow bidirectional exchange of pressure between the restoration chamber 40 of the drive 204 and the preload space 208. become.

The preload chamber 206 includes an opening 210, and the active element 16 of the drive unit 204 projects through this opening. The active portion 16 is supported within the opening 210, in particular so that it can be displaced there in a oscillating manner. This opening is sealed. A magnet device corresponding to the magnet device 120 is arranged in the preload space 208. Therefore, the same reference code is used. In that case, the active element 16 is attached to the actuator 116. The actuator 116 is similarly installed in the preload space 208.

The preload chamber 206 houses the magnet device. This magnet device is fixed. As a whole, the magnet device forms the application section 212, and the drive section 204 is attached to this application section.

A pump 214 that can set the pressure in the preload space 208 to a specified pressure is attached to the preload space 208. The pump 214 is connected via, for example, a three-way valve 216.

The pressure in the preload space 208 is set by the pump 214. The pressure in the restoration chamber 40 can be set by the control valve 192 by the pressure in the preload space 208.

The magnet device 120 can generate an electric current from the motion of the active portion 16.

In other respects, the free piston assembly 202 functions as described above with respect to other exemplary embodiments.

FIG. 10 schematically illustrates an exemplary tenth embodiment with reference to reference numeral 218. This embodiment includes a first drive unit 220 and a second drive unit 222. These drive units 220 and 222 are configured in the same manner as, for example, the drive unit 114 described above.

The first drive unit 220 and the second drive unit 222 are arranged so as to be mirror images of each other, for example. These drives are associated with a common supply device 224 for the fuel-oxidizer mixture and a common removal device 226 for the exhaust gas. Therefore, a dual system is formed.

The first application unit 228 is attached to the first drive unit 220, and the second application unit 230 is attached to the second drive unit 222. For example, the application units 228 and 230 correspond to the above-mentioned linear drive 130.

The arrangement is preferably symmetrical with respect to the central plane 232. Thereby, in this dual system, the drive unit and the application unit 220-228 and 222-230 can be overlapped.

The application units of the drives 220, 222, and 228, 230 function as described above.

10 free piston assembly 12 Drive unit 14 Application Department 16 Active element 18 Piston accommodating device 20 Piston device 22 Piston chamber 24 piston 26 directions 28 Longitudinal axis 30 1st piston surface 32 2nd piston surface 34 1st end wall 36 Second end wall 38 Expansion space 40 Restoration space 41 Spring element 42 Piston rod 44 opening 46 Bearing equipment 48 coupler 50 entrance port 51 inlet valve 52 valve 53 Pressure sensor 54 Exit port 55 Pressure sensor 56 valve 57 Ignition system 58 Second Embodiment 60 Preload chamber 62 Preload space 64 Second end face 66 valve 67 pump 68 Third Embodiment 70 Piston accommodating device 72 First end face 74 Second end face 76 Piston device 78 Piston device 80 piston rod 82 Valve element 84 coupler 86 Expansion space 88 Restoration space 90 Preload chamber 92 Preload space 94 First end face 96 Second end face 98 openings 100 end wall 102 Aperture 104 openings 106 channels 108 1st opening 110 2nd opening 112 Fourth Embodiment 114 Drive 116 Actuator 118 Longitudinal axis 120 magnet device 122 magnet 124 base 126 stator 128 coil 130 linear drive 132 Fifth Embodiment 134 Compressor 136 piston 138 cylinder 140 piston 142 end wall 144 compression chamber 146 Entrance port 148 Control valve 150 exit port 152 Control valve 154 Sixth Embodiment 156 piston 158 compressor 160 cylinders 162 1st end wall 164 Second end wall 166 1st compression chamber 168 Second compression chamber 170 piston rod 172 Seventh Embodiment 174 Drive 176 Actuator 178 Linear drive 180 magnet device 182 stator 184 8th Embodiment 186 Piston accommodating device 188 1st end wall 190 Second end wall 192 Control valve 194 Inside 196 Information surface 198 Arrow 202 9th Embodiment 204 Drive 206 Preload chamber 208 Preload space 210 openings 212 Application Department 214 pump 216 Three-way valve 218 10th Embodiment 220 1st drive unit 222 2nd drive unit 224 Supply device 226 Removal device 228 Part 1 Application 230 Part 2 Application 232 Central surface