EP1306539B1 - Two cycle hot gas engine - Google Patents

Abstract

An expansion piston (EP) (2) and a compression piston (CP) (4) fit along a common center axis (6) and operate when aligned in series. First gas chambers (GK1) in a compression cylinder component (5) on the underside (15) of the CP and in an expansion cylinder component (3) on the underside (16) of the EP connect via a first heater (18), a first regenerator (19) and a first cooler (20). <??>Second gas chambers (GK2) in the compression cylinder component on the topside (21) of the compression piston and in the expansion cylinder component on the topside (22) of the expansion piston connect via a second heater (24), a second regenerator (25) and a second cooler (26).

Description

The invention is in the field of hot gas engines.

Hot-gas engines based on the Stirling principle are among the oldest heat engines. Basically, with the help of hot-gas engines according to the Stirling principle or the related principles, a higher efficiency than with steam engines, diesel or gasoline engines can be achieved. With the help of hot gas engines heat is supplied to the outside of a working gas heater without combustion in the cylinder must be done. The potential use of renewable fuels and continuous combustion ensure environmentally friendly energy efficiency in conjunction with their high efficiency.

Hot-gas engines based on the Stirling principle are known as alpha, beta and gamma-type engines. In the alpha type, the total working gas volume is affected by the movement of an expansion piston and a compression piston. In the beta and gamma type, a displacer moves in a space of constant volume and only the working piston affects the total gas volume.

From the document US 5,146,750 a hot gas engine according to the sterling principle of the alpha-type is known. The known engine is a 1-cycle engine in which an expansion piston and a compression piston are arranged along a common center axis. Such a feature is also provided in a further 1-cycle hot gas engine, which is disclosed in the document DE 44 29 602 A1.

Despite the efficient energy conversion possible with the aid of hot gas engines, such motors have not yet been widely used for the generation of mechanical energy.

The object of the invention is to provide an improved two-cycle alpha-type hot gas engine with rectified gas cycles and 180 degrees phase offset, which has a simple structure and can be used flexibly for a permanent operation in various fields of application.

This object is achieved in a two-cycle hot gas engine with an expansion piston in an expansion cylinder component and a compression piston in a compression cylinder component according to the invention in that the expansion piston and the compression piston along a common center axis are arranged.

A significant advantage achieved with the invention over the prior art is that a motor structure has been provided for a two-cycle, alpha-type hot gas engine which, despite constructive simplicity, has a high power density provides. The proposed engine has constructive parallels to the beta type and combines these with the benefits of an alpha-type double-acting engine. The successive pistons ensure a slim gearbox and thus crankcase. For the crosshead or rail slide of both connecting rods can use a common rail.

Within a cylinder component no heat flow is induced because of the same temperature. This concerns the cylinder component wall and the pistons alike. This achieves a greater approximation to isothermal conditions.

Another advantage of the invention is that piston rod feedthroughs can be realized by a cylinder wall on the side of the cool compression cylinder part and thus are easy to seal.

In addition, the phase offset between expansion piston and compression piston can be set arbitrarily. The expansion volume can be varied with respect to the compression volume.

Furthermore, the symmetry ratios of the expansion and compression pistons can be used excellently for free-piston arrangements. In this way, pressure-resistant and completely pressure-tight motors can be built.

The enabled in the construction of the hot gas engine according to the invention two opposing cycles allow controllability over a cycle short circuit. Even with a non-pressurized transmission, the piston forces are low because of the two opposing cycles.

An expedient development of the invention provides that the expansion piston and the compression piston are arranged to operate in alignment in operation one behind the other. As a result, both pistons and their cylinder parts can be made the same diameter.

In a further development of the invention, it may be provided that first gas spaces, which are formed in the compression cylinder component on a lower side of the compression piston and in the expansion cylinder component on a lower side of the expansion piston, via a first heater, a first regenerator and a first radiator, and that second gas spaces formed in the compression cylinder member on an upper surface of the compression piston and in the expansion cylinder component on an upper surface of the expansion piston are connected via a second heater, a second regenerator and a second radiator. With this arrangement, two gas cycles are created which operate rectified with 180 degrees phase offset. The working gas connection line from the heater to the expansion cylinder component may consist, for the thermal separation of both components for each gas cycle, in part of a dimensionally defined straight tube which operates as a pulse tube

A compact design of the hot gas engine is supported in an advantageous embodiment of the invention in that between the expansion cylinder component and the compression cylinder component, a channel is formed, wherein in the channel, a piston rod of the expansion piston is arranged, which is pressure-tight manner through the channel. With the help of the channel, the hydraulic and, if necessary, thermal separation of the compression and the expansion cylinder component takes place.

A pressure-tight mounting of the piston rod of the expansion piston in the channel is facilitated in an advantageous embodiment of the invention in that the channel is formed in a connecting member which comprises at least a portion of the expansion cylinder component and at least a portion of the compression cylinder component. In this way, the channel can be created in a one-piece connector component.

To support the most compact design of the hot gas engine, an embodiment of the invention may advantageously provide that the piston rod of the expansion piston is movably inserted through a bore in the compression piston. In this way, a piston force propagation of the expansion piston can be realized to a transmission.

A movement of the compression piston along the piston rod of the expansion piston is made possible in an expedient development of the invention in that the. Piston rod of the expansion piston is movably guided through the compression piston.

Appropriately may be provided in a development that the piston rod of the expansion piston is movably guided through an opening in a housing of the compression cylinder component. In this way it is possible, the piston rod of the expansion piston To lead in the region of the compression cylinder component to the outside, for example, for coupling a connecting rod.

A space-saving design of the hot gas engine is made possible in a further development of the invention in that a piston attached to the compression piston has an opening, wherein the piston rod of the expansion piston is guided through the opening.

A common lead out of the piston rod of the compression piston and the piston rod of the expansion piston from the compression cylinder component is advantageously made possible in one embodiment of the invention in that the attached to the compression piston piston rod is pressure-tightly guided through the opening in the housing of the compression cylinder component.

A direct coupling of the movement of the compression piston to that of the expansion piston and the piston rod is made possible in a preferred embodiment of the invention in that the compression piston has a cavity in which a fixed to the piston rod of the expansion piston buffer piston is movably arranged so that in the cavity two buffer spaces are formed.

A transmission for transmitting power between the piston rod of the expansion piston and the compression piston can be saved in a development of the invention in that the two buffer spaces are formed in the cavity so that movement of the expansion piston and the attached thereto buffer piston in the cavity to a gas compression / Gas relaxation in the two buffer spaces leads to effect a movement of the compression piston. When a portion of the buffer space decreases, this creates an overpressure that pushes the compression piston. The other portion of the buffer space increases simultaneously, so that there is a negative pressure, which pulls the compression piston. A movement of the compression piston always occurs when the force resulting from the pressure difference between the two buffer space sections is greater than the required compression force.

A pressure-tight leading out the piston rod of the expansion piston from the compression cylinder component is facilitated in an expedient development of the invention in that a section extending beyond the compression cylinder component the piston rod of the expansion piston is received in a sealed interior of an extension sleeve, wherein the extension sleeve is attached to the outside of the compression cylinder component. Compared to the pressure-tight passage of the piston rod of the expansion piston through a housing of the compression cylinder component, the extension sleeve can be sealed to the cylinder component by means of simple means. By means of the attachment of permanent magnets to the section of the piston rod of the expansion piston extending beyond the compression cylinder component, a magnetic coupling can be achieved with an outer magnetic sleeve surrounding the extension sleeve or a linear generator with an outer stationary coil former surrounding the extension sleeve.

In a preferred embodiment of the invention it is provided that a distal end of the piston rod of the expansion piston is received in the cavity of the compression piston and that the expansion cylinder member and the compression cylinder member are movably mounted in a linear guide. The hollow compression piston thus has only a pressure-tight piston rod opening on the side facing the expansion piston. The cylinder, consisting of expansion and compression cylinder component, can be movably mounted in a linear guide. With the movement of the expansion piston, the cylinder comes into resonance and can perform work to the outside with complete pressure tightness. In this embodiment, the cylinder also moves heaters, regenerators and coolers, which can be used for improved heat transfer in the heaters and coolers.

In a preferred development of the invention can be provided that the compression piston has a cavity and that the piston rod of the expansion piston is formed through the cavity, wherein in the cavity on the piston rod of the expansion piston, a magnetic piston is arranged with magnetic means which interact with other magnetic means , and opposite portions of the magnetic means and the further magnetic means have a similar magnetic polarity. Instead of the hydraulic drive described with the buffer piston as a phase-offset magnetic drive of the compression piston is achieved. The magnetic piston does not need to be sealed in the compression piston. In this way, a magnetic drive is created. The compression piston is driven directly via the expansion piston. The net work can be tapped on the piston rod of the expansion piston, without the usual gear is required for this. With the help of the magnetic means and the others Magnetic means, the necessary phase offset between the expansion piston and compression piston can be realized simpler than in the above embodiment with buffer piston in the compression piston, as only at a very small distance between opposite portions of the magnetic means and the other magnetic means a repulsive force is so great that the Movement of the compression piston occurs. The necessary compression pressures may be adjusted by a suitable selection of the magnetic means and the other magnetic means.

A compact design of the hot gas engine is supported by the fact that the further magnetic means are arranged at least partially in the region of end faces of the compression piston.

The advantage of the hydraulic and magnetic drive of the compression piston over a mechanical is that the compression force does not have to be passed through the transmission. Consequently, the net work can be tapped on the piston rod of the expansion piston.

An efficient use of the energy used to heat the expansion cylinder component is achieved in an advantageous embodiment of the invention in that a compact heater is provided, which comprises a running as unfinished component cylindrical body with a combustion chamber and a heat transfer surface for working gas, wherein the heat transfer surface for working gas in a surface layer of the cylindrical base body is formed spirally. The spiral surface arrangement can create space-saving and streamlined heat transfer conditions. In order to close the spiral passages and provide the connections for the working gas, the spiral passages can be closed by sleeves shrunk into and onto the cylindrical base body, to which the gas connecting pieces are fastened. An inner sleeve, which simultaneously forms the combustion chamber, can be closed on one side and leaves below a defined Spiralgangbereich the flue gas spiral free to form a turning chamber for the flue gas.

Advantageously, it can be provided that in the region of a surface of the cylindrical base body, a respective heat transfer surface for combustion air and flue gas is formed spirally.

The use of the compact heater for two working gases is made possible in a development of the invention in that the heat transfer surface for working gas comprises a working gas spiral for a first working gas and at least one of the working gas spiral hydraulically separate further working gas spiral for a second working gas. In this way, a single compact heater can be used for the operation of the embodiments of the hot gas engines described above.

The production of the compact heater is facilitated a further development of the invention in that the heat transfer surface for working gas is formed on an outer circumference of the cylindrical body.

To support a space-saving design of the compact heater can be provided in an advantageous development of the invention that the heat transfer surface is formed for combustion air on the outer circumference of the cylindrical body.

An optimized utilization of the surface of the cylindrical base body is ensured in a preferred embodiment of the invention in that the heat transfer surface is formed for flue gas on an inner circumference of the cylindrical body.

Appropriately may be provided in one embodiment of the invention that the heat transfer surface for working gas in a region around the combustion chamber and the heat transfer surface for combustion air in a region above the combustion chamber of the cylindrical body are arranged so that in the combustion chamber generated heat energy initially the heat transfer surface for Working gas and then heat the heat transfer surface for combustion air. As a result, the heat energy generated by means of a fuel in the combustion chamber is used efficiently in the operation of the hot gas engine.

A preferred embodiment of the invention provides that the cylindrical base body is designed with the aid of two basic body components, wherein the two basic body components are connected by means of a disc-shaped perforated member and the disc-shaped perforated member has a connecting channel for guiding combustion air into the combustion chamber and a flue gas connecting channel for connecting of heat transfer surfaces for flue gas in the two main body components. This makes it possible, on one of the two basic body components a continuous spiral heat transfer surface for to provide the combustion air, which can be created by turning, so that the complex milling of the Wänneübertragungsfläche is saved.

Figur 1

eine schematische Darstellung eines Zwei-Zyklen-Heißgasmotors im Querschnitt;

Figur 2

eine schematische Darstellung eines Zwei-Zyklen-Heißgasmotors im Querschnitt, wobei ein Kompressionskolben einen Hohlraum aufweist;

Figur 3

den Zwei-Zyklen-Heißgasmotor nach Figur 2, wobei ein Ende einer Kolbenstange eines Expansionskolbens in einer Verlängerungshülse aufgenommen ist;

Figur 4

eine schematische Darstellung eines Zwei-Zyklen-Heißgasmotors mit einer Linearführung im Querschnitt;

Figur 5

eine schematische Darstellung eines Zwei-Zyklen-Heißgasmotors mit magnetischem Antrieb im Querschnitt;

Figur 6

eine schematische Darstellung eines Zwei-Zyklen-Heißgasmotors, wobei eine Mittelachse eines Spiralerhitzers parallel zu einer Mittelachse eines Zylinders gebildet ist;

Figur 7

einen Kompakterhitzer;

Figur 8

den Kompakterhitzer nach Figur 7 im Schnitt entlang einer Linie AA' in Figur 7;

Figur 9

den Kompakterhitzer nach Figur 7 in Draufsicht;

Figur 10

einen weiteren Kompakterhitzer;

Figur 11

den weiteren Kompakterhitzer nach Figur 10 im Schnitt entlang einer Linie BB' in Figur 10;

Figur 12

den weiteren Komapaktserhitzer nach Figur 10 in Draufsicht; und

Figur 13

eine schematische Darstellung eines Zwei-Zyklen-Heißgasmotors.

The invention is explained in more detail below with reference to exemplary embodiments with reference to a drawing. Hereby show:

FIG. 1

a schematic representation of a two-cycle hot gas engine in cross section;

FIG. 2

a schematic representation of a two-cycle hot gas engine in cross section, wherein a compression piston has a cavity;

FIG. 3

the two-cycle hot gas engine of Figure 2, wherein one end of a piston rod of an expansion piston is received in an extension sleeve;

FIG. 4

a schematic representation of a two-cycle hot gas engine with a linear guide in cross section;

FIG. 5

a schematic representation of a two-cycle hot gas engine with magnetic drive in cross section;

FIG. 6

a schematic representation of a two-cycle hot gas engine, wherein a center axis of a spiral heater is formed parallel to a central axis of a cylinder;

FIG. 7

a compact heater;

FIG. 8

the compact heater of Figure 7 in section along a line AA 'in Figure 7;

FIG. 9

the compact heater of Figure 7 in plan view;

FIG. 10

another compact heater;

FIG. 11

the further compact heater according to Figure 10 in section along a line BB 'in Figure 10;

FIG. 12

the other Komapaktserhitzer of Figure 10 in plan view; and

FIG. 13

a schematic representation of a two-cycle hot gas engine.

Figure 1 shows a schematic representation of a two-cycle HeiBgasmotors with a cylinder housing 1. In the cylinder housing 1, an expansion piston 2 in an expansion cylinder component 3 and a compression piston 4 in a Kompressionsionszylinderbauteil 5 arranged. The expansion piston 2 and the compression piston 4 are arranged one behind the other along a common center line 6. The expansion cylinder component 3 and the compression cylinder component 5 are connected to one another via a connecting component 7, in which a channel 8 is formed. In the channel 8, a piston rod 9 of the expansion piston 2 is guided pressure-tight. The piston rod 9 of the expansion piston 2 extends through an opening 4a in the compression piston 4 and through the compression piston 4 and a piston rod 10 of the compression piston 4 therethrough.

The piston rod 10 of the compression piston 4 is guided through an opening 11 in the Kompressionsionszylinderbauteil 5 through to the outside. The passage of the piston rod 10 of the compression piston 4 and the piston rod 9 of the expansion piston 2 mounted thereon out of the compression cylinder component 5 is pressure-tight. The piston rod 9 of the expansion piston 2 is guided through an opening 10 a in the piston rod 10. To the piston rod 9 of the expansion piston 2 and the piston rod 10 of the compression piston 4 are each a connecting rod 12, 13 is coupled, so that the piston rods 9, 10 are connected to a crankshaft 14.

On an underside 15 of the compression piston 4 and on an underside 16 of the expansion piston 2, first gas spaces GH1 and GK1 are formed. The first gas chambers GH1, GK1 are connected via a first connecting channel 17. Integrated in the connecting channel 17 are a first heater 18, a first regenerator 19 and a first cooler 20.

On an upper side 21 of the compression piston 4 and on an upper side 22 of the expansion piston 2, second gas spaces GK2 and GH2 are created, which communicate via a second connecting channel 23. In the second connection channel 23, a second heater 24, a second regenerator 25 and a second cooler 26 are arranged.

In the two-cycle hot gas engine illustrated in FIG. 1, the compression cylinder component 5 and the expansion cylinder component 3 are thermally separated. This thermal separation makes it possible to realize the removal of the piston rods 9 and 10, respectively, on the cold side of the hot gas engine in the area of the compression cylinder component 5 Sealing problems, as they often occur in the art, significantly alleviates.

The expansion cylinder member 3 and the expansion piston 2 may be made of a high-temperature material. In this embodiment can be by means of a wall 27 of the expansion cylinder component 3 formed heat pipe and gas channels (not shown in Figure 1) the gas spaces GH1, GH2 equally heat isothermally. The compression cylinder component 5 may for example be made of Duranglas. The compression piston 4 can be conveniently made of graphite.

FIG. 2 shows a schematic representation of a two-cycle hot gas engine, in which the reference symbols used in FIG. 1 are used for the same features. In contrast to the two-cycle hot gas engine according to FIG. 1, the compression piston 4 has a cavity 30. In the cavity 30, a buffer piston 31 is arranged, which is formed on the piston rod 9 of the expansion piston 2. With the help of the buffer piston 31 30 buffer spaces P1 and P2 are created in the cavity. In a movement of the expansion piston 2, the working gas, which is located in the buffer spaces P1, P2 is compressed / relaxed, which leads to the initiation of an upward and a downward movement of the compression piston 4. In this way, the gas chambers GH1, GH2 advance in a defined manner ahead of the gas spaces GK1, GK2. By means of magnets 32a-32d, a striking of the compression piston 4 on the housing 33 of the compression cylinder component 5 is prevented. For this purpose, the magnets 32a and 32b and 32c and 32d each have an opposite magnetic polarity.

Due to the provision of the buffer piston 31, a transmission for coupling the piston rod 9 of the expansion piston 2 to the compression piston 4 can be dispensed with in the embodiment shown in FIG. The coupling is created by means of the buffer piston 31 and the resulting buffer spaces P1, P2. According to Figure 2, the piston rod 9 of the expansion piston 2 is coupled via a crosshead 34 to the connecting rod 13.

FIG. 3 shows the two-cycle hot gas engine according to FIG. 2, but with an end 40 of the piston rod 9 of the expansion piston 2 extending beyond the compression cylinder component 5 being accommodated in an extension sleeve 41. The extension sleeve 41 is pressure-tightly mounted on the compression cylinder component 5. With the aid of a magnetic coupling 42, the piston rod 9 of the expansion piston 2 is coupled to an outer guide piston 43, which slides in a cylinder 44 of the guide piston 43. The guide piston 43 in turn communicates with the connecting rod 13. The guide piston 43 may be lubricated together with its cylinder 44 and be performed similarly to a gasoline engine.

Figure 4 shows another two-cycle hot gas engine, wherein for like features, the reference numerals used in Figures 1 to 3 are used. In the embodiment of Figure 4 ends a distal end 50 of the piston rod 9 of the expansion piston 2 on the buffer piston 31. In contrast to the embodiments in Figures 1 to 3 in the hot gas engine of Figure 4 is not leading out the piston rod 9 of the expansion piston 2 from the Compression cylinder component 5 is provided. In this way, the cylinder housing 1 is completely closed.

On the compression cylinder component 5, an extension 51 is mounted, which is movably mounted in a part 52 of a linear guide. The extension 51 is connected via the connecting rod 13 with the crankshaft 14. Another part 53 of the linear guide is provided in the region of the connecting component 7. The Linearflüirung provides for a rectilinear movement of the cylinder housing 1. Together with the cylinder housing 1, the first radiator 18, the first regenerator 19, the first heater 20, the second radiator 24, the second regenerator 25 and the second heater move 26. A momentum transfer to initiate the movement of the compression piston 4, as has been described in connection with the embodiments of Figures 2 and 3, due to the gas compression in the buffer spaces P1, P2.

Figure 5 shows a schematic representation of another embodiment of a two-cycle hot gas engine with a cylinder housing 100, a compression cylinder member 101 and an expansion cylinder member 102. In the compression cylinder member 101, a compression piston 103 is arranged. In the expansion cylinder member 102, an expansion piston 104 is supported. The compression cylinder component 101 and the expansion cylinder component 102 are connected via a connecting component 105, in which a piston rod 106 of the expansion piston 104 is mounted in a pressure-tight manner. For sealing, a seal 107 is provided.

As in the embodiments according to FIGS. 1 to 4, first and second gas spaces GH1, GK1 and GH2, GK2 are formed on both sides of the compression piston 103 and the expansion piston 104. The first and second gas chambers GH1, GH2, GK1, GK2 each have connections 108, 109, 110 and 111, respectively. Between the connections 108-111, heaters, regenerators and coolers are shown in FIGS. 1 to 4 (in FIG. 5) not shown) coupled. The expansion piston 104 is held on the piston rod 106 by means of a piston mounting nut 112. Between a piston clamping plate 113 and the piston fixing nut 112, a tension spring 114 is mounted. A further piston clamping plate 115 is fastened to the piston rod 106 by means of a fastening pin 116.

In contrast to the embodiment according to FIGS. 1 to 4, in the hot gas engine according to FIG. 5, a magnetic drive of the compression piston 103 is provided. The magnetic drive comprises a plurality of magnetic means 121, 122, 123. The plurality of magnetic means 121-123 each have disc-shaped pole plates 121a, 121b, 122a, 122b, 123a, 123b. Opposed pole plates, such as the pole plates 122b and 123a, have the same magnetic polarity so that repulsive forces act as the opposing pole plates move toward each other. The repulsive forces develop a large force usually, however, only at actual approach of the opposite pole plates. In comparison with the embodiments according to FIGS. 2 to 4, the necessity of sealing the buffer piston 31 with respect to the compression piston 103 is eliminated when using the magnetic drive since the initiation of the movement of the compression piston 103 is not due to gas compression in buffer spaces P1, P2 (cf. FIGS. 2 to 4), but is effected by the magnetic repulsion force between opposing pole plates. Magnetic means 120, 124, which also have pole plates 120a, 124a, are provided to prevent the abutment of the compression piston 103 on the compression cylinder component 101.

The magnets 120-124 can be carried out by means of magnetic drums with annularly arranged bar magnets. A seal 107, 126, 127, 128 is arranged around the piston rod 106 in the case of the magnets 120, 121, 123 and 124 in order to drive the piston rod 106 in a pressure-tight manner through the magnets 120, 121, 123, 124. In this way, the seals 107, 126-128 delimit the two cycles from each other. The magnet 122 is fixed to the piston rod 106. The seals 107, 126-128 are made of Teflon, for example.

The piston rod 106 of the expansion piston 104 is made of a non-magnetic and electrically poorly conductive material, such as V4A steel. The cylinder component is designed in several parts and is held together by means of screw 129, 130, 131, 132.

In Figure 5, a stroke S 1 of the expansion piston 103 is indicated schematically. About a change of a hollow length H1 of the compression piston 103 and a hollow length H2 of the compression cylinder member 101, adjustment can be made such that the stroke S1 of the expansion piston 103 is greater than, equal to or smaller than a stroke S2 of the compression piston 104. As a result, the compression ratio of the engine and the discontinuous piston movement of the Kompressionsionskolbens 103 can be influenced.

FIG. 6 shows a schematic representation of a two-cycle hot gas engine 200 with a compression cylinder component 201 and an expansion cylinder component 202. A radiator 203 has a central axis 204, which is arranged substantially parallel to the central axis 205 of a further radiator 206. The central axis 204 of the radiator 203 and the center axis 205 of the further radiator 206 are substantially perpendicular to a central axis 207 of the compression cylinder member 201 and the expansion cylinder member 202. A central axis 208 of a regenerator 209 is substantially parallel to a central axis 210 of another regenerator 211 and Central axis 207 of the compression cylinder component 201. In Figure 6, two consecutive heating coils 212 and 213 are further shown. For low power motors, the two heater coils 212, 213 may be implemented as a single tube or as a cylindrical split tube heater. This makes it possible, with a burner, which is arranged within the two heating coils 212, 213 located one behind the other, to heat the gas spaces of both cycles of the engine. In this way, an otherwise necessary second burner is saved.

Figure 7 shows a compact heater 300 which may be used in conjunction with any hot gas engines, which means that the compact heater 300 is not only advantageous in connection with the two-cycle hot gas engines described in connection with Figures 1-6 , The use for beta and gamma motors is advantageous if the spiral connections of the motor geometry can be adapted.

The compact heater 300 has a cylindrical sleeve 500, to which a combustion air connection 302, a first working gas port 303, a second working gas port 304 and a first working gas outlet 305 are formed. A second working gas outlet is located on a side facing away from the viewer of Figure 7 back of the compact heater 300 and is therefore not seen in Figure 7. At a lower end 306 of the compact heater 300, a burner 307 is connected.

FIG. 8 shows the compact heater 300 according to FIG. 7 in section along a line AA 'in FIG. 7. On an outer circumference 308 of a cylindrical basic body 301, a heat transfer surface for combustion air 309 in the form of a channel is spirally formed. The spiral heat transfer surface for combustion air 309 communicates with the combustion air port 302. The combustion air passes through the combustion air port 302 in the spiral heat transfer surface for combustion air 309 and via a connecting pipe 310 in a combustion chamber 311, where by means of the burner 307, a fuel is burned to produce combustion heat energy. It may be provided to connect a fan to the combustion air inlet 302 to introduce the combustion air at a predetermined pressure. When burning in the combustion chamber 311, flue gas or exhaust gas is formed, which is transferred at the lower end of the combustion chamber 311 by means of a turning chamber plate 312 in a spiral heat transfer surface for flue gas 313, which is formed along a channel and on an inner circumference 314 of the cylindrical body 301 extends spirally. On the way to the chimney 315, the flue gas heats first working gas in heat transfer surfaces for working gas 316, 317, which are also formed on the outer periphery 308 of the cylindrical body 301. On its further way along the heat transfer surface for flue gas 313, the flue gas then heats heat transfer surface for combustion air 309.

FIG. 9 shows the compact heater 300 according to FIG. 7 in plan view.

FIGS. 10, 11 and 12 show a further compact heater 400, the same reference numerals being used for the same features as in connection with FIGS. 7, 8 and 9. The cylindrical main body 301 is formed in the embodiment according to the figures 10 to 12 of two basic body components 401 and 402, which are hidden in Figure 10. The two basic body components 401 and 402 are connected to one another by means of a perforated component 403. According to FIG. 11, a combustion air connecting passage 404 is provided in the perforated component 403, through which combustion air can pass from the spiral heat transfer surface for combustion air 309 into the combustion chamber 311. Thus, in the embodiment according to FIGS. 10 to 12, the combustion air connection channel 404 assumes the function of the connection channel 310 in FIG. 8. On the inner circumference 314 of the basic body components 401, 402, two inner sleeves 510, 511 are arranged.

FIG. 12 shows the further compact heater 400 according to FIG. 10 in plan view.

For hot-gas engines with low power and speeds between 100 and 500 rpm, it is possible to use single-pipe heaters. The compact heater 300 shown in FIGS. 7 to 9 and the further compact heater 400 shown in FIGS. 10 to 12 belong to this type of single-pipe heater. The main reason for the use of Einrohrerhitzern is the fact that in already built hot gas engines, the cost of the heater significantly affect the overall system costs.

The helical design of the heat transfer surfaces in the compact heater 300 and the other compact heater 400 is suitable for a design as a single-pipe heater. From today's perspective, a production of the compact heater 300 and the further compact heater 400 made of a high-temperature metal is an advantageous solution, if the conditions of high temperature resistance, a Tinder strength and a sufficient sealability of the connections are guaranteed.

In the compact heater 300 and the other compact heater 400, the cylindrical body 301 may be formed by means of a mold, which then also has the spiral heat transfer surfaces. Here, suitable wall thicknesses and draft angles of the spiral channels for forming the heat transfer surfaces have to be considered. If an operating temperature does not exceed 600 ° C, a production of the insert material SiMo-alloyed cast iron with ductile iron is an expedient solution. Another possibility is to form the cylindrical basic body 301 by turning and / or milling the spiral channels on the inner and outer perimeters 314, 308. Here, a cylindrical high-temperature hollow steel can be used. An outer sleeve 500 is shrunk and seals the spiral heat transfer surfaces on the outer periphery 308. To cover the heat transfer surface for flue gas 313, the inner sleeve 510 is shrunk. The sleeve 500 is shrunk with the ports 302-305. The use of shrinkage is possible because in the compact heater 300 and the further compact heater 400, the heat of the burner 307 is always supplied from the inside. The tightness is then ensured, since first the inner sleeve 510, then the cylindrical base body 301 and finally the outer sleeve 500 expand. Cooling takes place from outside to inside and is therefore also uncritical with regard to the tightness of the spiral-shaped heat transfer surfaces.

The compact heater 300 and the further compact heater 400 allow a compact design of heaters that can be used for any hot gas engines. In addition, a cost-effective production is possible in the described embodiment. In addition, favorable Wärmeüberdragungsverhältnisse are formed, with only small pressure losses occur. The embodiment of the heat transfer surface for working gas described with reference to FIGS. 7 to 12 enables the formation of at least two working gas chambers which are heated by a burner. The use of high temperature casting is possible. If the compact heater 300 and the further compact heater 400 are used in the upright arrangement shown in Figures 7, 8 and 10, 11, a direct forwarding of the flue gas to the chimney is made possible.

FIG. 13 shows a schematic representation of a two-cycle hot gas engine 500 connected to a work machine 600, wherein the same reference numbers are used for the same features. Two membrane primary sides 601, 602 are hydraulically connected to the working gas of the working machine 600 via two gas lines 610, 611 and are set in vibration by the pressure fluctuation thereof. Two membrane secondary sides 603, 604 are formed as a pump working space. Thus, the membrane pumps a liquid 605 by opening at least one outlet valve 607 at positive pressure and closing at least one inlet valve 606 and closing at least one outlet valve 607 under vacuum and opening an inlet valve 606.

For this application, it is advantageous that the two-cycle hot gas engine 500 is a motor that vibrates with its two working gas chambers two hydraulically isolated membranes 608, 609 or deformable surfaces with 180 ° phase offset. In this way, the work yield can be doubled and a pulse smoothing can be achieved.

In the two-cycle hot gas engine 500, the working gas pressure fluctuations of the engine can be used without mechanical force propagation in order to set at least one with the working gas on the primary side in the pressure composite diaphragm of a working machine of a drive or the piezoelectric surface of a power generator in vibration. Appropriately, it can be provided that the working machine 600 is a double-acting diaphragm pump, the membrane primary sides are hydraulically connected to the engine working gas and the membranes are vibrated by the pressure fluctuations.

In conjunction with the two-cycle hot gas engine 500 may be advantageously provided that in a power generator, the deformable surface of a piezoelectric transducer is hydraulically connected to the engine working gas and is cyclically deformed by the pressure fluctuation.

The use of the two-cycle hot gas engine 500 described in connection with FIG. 13 can also be provided for the motors according to FIGS. 1 to 6.

The features of the invention disclosed in the foregoing description, the claims and the drawing may be of importance both individually and in any combination for the realization of the invention in its various Ausftihrungsformen.

Claims (27)

1. A two-cycle hot-gas engine in accordance with the Alpha-Type Stirling principle, whereby the two gas cylinders act in the same direction with a 180° phase shift, comprising an expansion piston (2; 104) in an expansion cylinder member (3; 102) and a compression piston (4; 103) in a compression cylinder member (5; 101), characterized in that the expansion piston (2; 101) and the compression piston (4; 103) are disposed along a common axis (6).
2. The two-cycle hot-gas engine as claimed in claim 1, characterized in that the expansion piston (2; 104) and the compression piston (4; 103) are disposed so as to operate in alignment one behind the other.
3. The two-cycle hot-gas engine as claimed in claim 1 or claim 2, characterized in that first gas chambers (GH1 and GK1, respectively) formed at a bottom end (15) of the compression piston (4) in the compression cylinder member (5) and at a bottom end (16) of the expansion piston (2) in the expansion cylinder member (3), respectively, communicate through a first heater (18), a first regenerator (19) and a first cooler (20), and that second gas chambers (GH2 and GK2, respectively) formed at a top end (21) of the compression piston (4) in the compression cylinder member (5) and at a top end (22) of the expansion piston (2) in the expansion cylinder member (3), respectively, communicate through a second heater (24), a second regenerator (25), and a second cooler (26).
4. The two-cycle hot-gas engine as claimed in one of the preceding claims, characterized in that a passage (8) is formed between the expansion cylinder member (3) and the compression cylinder member (5), a piston rod (9; 106) of the expansion piston (2) being arranged to extend through the passage (8) in pressure-tight engagement.
5. The two-cycle hot-gas engine as claimed in claim 4, characterized in that the passage (8) is formed in a connecting member (7; 105) which comprises at least a portion of the expansion cylinder member (3; 102) and at least a portion of the compression cylinder member (5; 101).
6. The two-cycle hot-gas engine as claimed in one of the preceding claims, characterized in that the piston rod (9; 106) of the expansion piston (2; 104) is movably introduced into the compression piston (4; 103) through a bore (4a) in the compression piston (4; 103).
7. The two-cycle hot-gas engine as claimed in claim 6, characterized in that the piston rod (9; 106) of the expansion piston (2; 104) is movably passed through the compression piston (4; 103).
8. The two-cycle hot-gas engine as claimed in claim 7, characterized in that the piston rod (9; 106) of the expansion piston (2; 104) is movably passed through a bore (11) in a casing of the compression cylinder member (5; 101).
9. The two-cycle hot-gas engine as claimed in claim 7 or claim 8, characterized in that a piston rod (10) attached to the compression piston (4) is formed with an opening (10a) through which the piston rod (9) of the expansion piston (2) is passed.
10. The two-cycle hot-gas engine as claimed in claim 8 or claim 9, characterized in that the piston rod (10) attached to the compression piston (4) is passed in pressure-tight engagement through the bore (11) in the casing of the compression cylinder member (5).
11. The two-cycle hot-gas engine as claimed in claim 6, characterized in that the compression piston (4; 103) comprises a cavity (30) in which a buffer piston (31) secured to the piston rod (9) of the expansion piston (2; 104) is movably arranged, whereby two buffer chambers (P1, P2) are defined in the cavity (30).
12. The two-cycle hot-gas engine as claimed in claim 11, characterized in that the two buffer chambers (P1, P2) in the cavity (30) are formed such that movement inside the cavity (30) of the expansion piston (2; 104) and the buffer piston (31) secured to the same results in compression/expansion of a working gas in the two buffer chambers (P1, P2) to cause movement of the compression piston (4; 103).
13. The two-cycle hot-gas engine as claimed in claim 11 pr claim 12, characterized in that a portion (40) of the piston rod (9) of the expansion piston (2) extending beyond the compression cylinder member (5) is received in a sealed interior space of an extension sleeve (41) which is mounted on the outside of the compression cylinder member (5).
14. The two-cycle hot-gas engine as claimed in one of the preceding claims, characterized in that pressure variations of the operating gas are used to cause vibrations of at least one diaphragm, the primary side of which is influenced by the working gas, said diaphragm belonging to a machine or a drive means, or being the piezoelectric surface of a power generator.
15. The two-cycle hot-gas engine as claimed in claim 14, characterized in that the machine is a double-acting diaphragm pump (600), the primary diaphragm sides (601, 602) of which are hydraulically connected to the working gas and the pressure variations of which cause the diaphragms (608, 609) to vibrate.
16. The two-cycle hot-gas engine as claimed in claim 15, characterized in that secondary diaphragm sides of the diaphragm pump (600) are designed as pump working chambers, and that the diaphragm pumps a liquid by the closing of at least one outlet valve (607) and the opening of at least one inlet valve (606) when positive pressure prevails.
17. The two-cycle hot-gas engine as claimed in claim 11 or claim 12, characterized in that a distal end (50) of the piston rod (9) of the expansion piston (2) is received in the cavity (30) of the compression piston (4), and in that the compression cylinder member (5) and the expansion cylinder member (3) are movably supported in a linear guide means (52, 53).
18. The two-cycle hot-gas engine as claimed in claim 6, characterized in that the compression piston (103) comprises a cavity (30) inside of which a magnetic piston with magnetic means (122) is attached to the piston rod (106) of the expansion piston (104), the magnetic means (122) interacting with further magnetic means (121, 123), and opposed portions (121b, 122a; 122b, 123a) of the magnetic means (122) and the further magnetic means (121, 123) having like magnetic polarity.
19. The two-cycle hot-gas engine as claimed in claim 18, characterized in that the further magnetic means (122, 123) are disposed at least partly in the area of front end surfaces of the compression piston (103).
20. The two-cycle hot-gas engine as claimed in one of the preceding claims, characterized by a compact heater (300; 400) including a cylindrical basic body (301) designed as an integral structural component with a combustion chamber (311) and a heat transmission surface for working gas, said heat transmission surface for working gas being formed in spiral shape in a surface layer of the cylindrical basic body (301).
21. The two-cycle hot-gas engine as claimed in claim 20, characterized in that respective heat transmission surfaces for combustion air and flue gas are provided in spiral configuration in the range of a surface of the cylindrical basic body (301).
22. The two-cycle hot-gas engine as claimed in claim 20 or claim 21, characterized in that the heat transmission surface for working gas comprises a working gas spiral for a first working gas and at least one other working gas spiral, hydraulically separated from the working gas spiral, for a second working gas.
23. The two-cycle hot-gas engine as claimed in claim 20, claim 21 or claim 22, characterized in that the heat transmission surface for working gas is provided on an outer circumference (308) of the cylindrical basic body (301).
24. The two-cycle hot-gas engine as claimed in one of the claims 21 to 23, characterized in that the heat transmission surface for combustion air is provided on the outer circumference (308) of the cylindrical basic body (301).
25. The two-cycle hot-gas engine as claimed in one of the claims 21 to 24, characterized in that the heat transmission surface for flue gas is provided on an inner circumference (314) of the cylindrical basic body (301).
26. The two-cycle hot-gas engine as claimed in one of the claims 21 to 25, characterized in that the heat transmission surface for working gas in an area around the combustion chamber (311) and the heat transmission surface for combustion air in an area above the combustion chamber (311) of the cylindrical basic body (301) are arranged such that the thermal energy generated in the combustion chamber (311) can first heat the heat transmission surface for working gas and subsequently heat the heat transmission surface for combustion air.
27. The two-cycle hot-gas engine as claimed in one of the claims 20 to 26, characterized in that the cylindrical basic body (301) comprises two basic body components (401; 402) which are connected by a disc-shaped perforated element (403), the disc-shaped perforated element (403) comprising a connecting conduit (404) for directing combustion air into the combustion chamber (311) and a flue gas connecting conduit (405) for connecting heat transmission surfaces for flue gas in the two basic body components (401; 402).

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