WO2007110184A2

WO2007110184A2 - Hot-gas engine

Info

Publication number: WO2007110184A2
Application number: PCT/EP2007/002499
Authority: WO
Inventors: Josef Gail
Original assignee: Josef Gail
Priority date: 2006-03-23
Filing date: 2007-03-21
Publication date: 2007-10-04
Also published as: DE102006050914A1; WO2007110184A3

Abstract

A cylinder/piston unit (1) working according to the Stirling cycle is proposed in which a freely oscillating working piston (9) drives a fluid pressure pump (55), whereas a displacer piston (13) is moved externally in a positive manner with a predeterminable motion cycle by an external drive, for example, a double-acting hydraulic cylinder (27).

Description

Hot gas engine

description

The invention relates to a working according to the Stirling hot gas engine.

Conventional Stirling engines have a cylinder-piston unit with a working cylinder section, in which a working piston is guided displaceably sealed and a Verdrängerzylinderabschnitt, in which a displacer piston is slidably guided. Of the

Displacer cylinder section, the working cylinder section and the

Working pistons together define a closed, with a working gas, such as air, filled gas process space whose volume varies according to the oscillating displacement movement of the working piston. The displacer divides the gas process space into two

Chambers, of which a first of the two chambers of the

Displacement piston and the working piston is limited. The two chambers are connected to one another via a bypass path for the working gas bridging the displacer piston.

Such an arrangement forms a working machine which operates according to the Stirling cycle when, by means of a heater arrangement, the working gas is heated in a second of the two chambers and cooled by means of a cooling arrangement in the first of the two chambers. The working piston is provided with an output arrangement, while the displacer piston is oscillated back and forth by a drive arrangement in the Verdrängerzylinderabschnitt. The movement phases of the displacement piston and the working piston are coordinated so that the state of the working gas in the gas process space at least approximately corresponding to the existing of two isotherms and two isochores Stirling cycle itself changes. The displacer displaces heated working gas into the first chamber as it reciprocates in the second chamber and displaces cooled working gas back into the second chamber in the first chamber. The alternating heating and cooling of the working gas causes an alternately increasing and decreasing the working gas pressure, which leads to the oscillating displacement movement of the working piston. In order to increase the efficiency of the cycle, it is common in the bypass path to the displacer a regenerator, ie to arrange a heat storage that stores a portion of the heat while the displacer displaces the heated working gas from the second chamber into the first chamber and the stored heat the working gas returns when it flows back cooled from the first chamber into the second chamber. Usually, the bypass path runs outside the displacement cylinder section, wherein the regenerator often has the shape of a wire mesh body.

In conventional Stirling engines, the power piston operates via a connecting rod on an output crankshaft. Also, the displacer piston is coupled via a connecting rod with the crankshaft, wherein the displacer associated crankshaft crank the crank throw of the working piston is offset by 90 degrees leading. The displacement movement of the displacement piston coupled directly to the output crankshaft continuously follows a sinusoidal time profile. This deteriorates the efficiency of the machine. In addition, it is difficult to avoid imbalance and vibrations of the machine in this conventional crankshaft output. To improve the mass balance, it is also known in this context in a so-called "Rhombentriebwerk" the drive of the displacer on the one hand and the output of the output piston on the other hand divided into two mutually coupled, but counter-rotating crankshafts Such engines have in practice as too expensive proved. To improve the efficiency was trying to drive the displacer discontinuously. The displacer was moved by a cam drive, which in turn is driven by the output crankshaft of the working piston. Again, these are comparatively expensive constructions.

It is an object of the invention to provide a particular operating as a motor hot gas engine, which has a high efficiency with a simple construction.

The invention is based on a hot gas machine comprising:

- A cylinder-piston unit with a working cylinder section in which a working piston is guided displaceably sealed and a Verdrängerzylinderabschnitt in which a displacer is guided displaceably, wherein the Verdrängerzylinderabschnitt, the working cylinder section and the working piston together define a closed, filled with a working gas gas process space whose volume varies according to the displacement movement of the working piston and the displacer divides the gas process space into two chambers, of which a first of the two chambers is delimited by the displacer piston and the working piston and wherein the two chambers are interconnected via a bypass path bridging the displacer piston for the working gas a cooling arrangement for cooling the working gas in the first of the two chambers,

a heater arrangement for heating the working gas in a second of the two chambers,

- An oscillating the displacer piston in the displacement cylinder section reciprocating drive assembly and

- An output assembly connected to the working piston. To achieve the above-mentioned object, it is provided that the drive arrangement of the displacement piston is designed as a controllable third drive whose movement stroke is forcibly changed relative to the movement stroke of the working piston.

In such a hot air machine, the drive of the displacer performs the movement stroke of the working piston. The clock rate and possibly the phase position of the movement stroke of the displacer relative to the movement stroke of the working piston can thus be changed differently than with mechanical coupling of the displacer drive to the working piston output simply. In particular, the movement sequence of the displacer piston can be designed to increase the efficiency of the machine also readily discontinuous.

In a preferred embodiment, the external drive comprises a via a piston rod connected to the displacer Druckfluid- drive cylinder to which via a controlled by a control control valve assembly pressure fluid with zwangsweise predetermined clock frequency and / or forcibly predetermined clock phase can be fed. This is preferably a hydraulic drive cylinder. The drive cylinder may be single-acting, especially when the displacer cylinder is associated with a return spring. However, double-acting drive cylinders are preferred because they enable jerky-discontinuous positioning movements of the displacer piston in both actuating directions.

The external drive may, however, also be an electric motor connected to the displacer piston via a crank mechanism, whose output rotational speed and / or output phase can be predetermined by means of a control. It goes without saying that the electric motor can also be operated discontinuously here, in particular if it is a stepping motor. The displacer cylinder portion and the working cylinder portion may have staggered or inclined cylinder axes in a conventional manner as far as the cylinder portions for the formation of the common gas process space are connected to each other. However, particularly simple constructions can be obtained if the displacement cylinder section and the working cylinder section are arranged coaxially next to one another. Such constructions are stable and occupy comparatively little space. In such a construction, the displacer piston and the working piston are axially opposite.

The output arrangement of the drive piston on the one hand and the external drive of the displacer on the other hand can be connected separately in such a construction from opposite sides with the piston. However, the piston rod associated with the displacer piston then has to be led out of the displacer cylinder section through the region of the heating arrangement, which can lead to sealing problems. As a cheaper it has been found when the external drive is arranged on the side opposite the displacement cylinder axially facing away from the working cylinder portion and is accordingly connected via a piston rod through the working piston with the displacer.

The output arrangement of the working piston may conventionally be an output crankshaft. In a substantial improvement, which also has independent inventive significance, it is provided that the output arrangement comprises a fluid pressure pump driven by the working piston. Compared with the conventional output via a crankshaft, this has the advantage that the stroke of the working piston can adjust itself free-swinging and is not predetermined by a defined Kurbelwellenkröpfung. The fluid pressure pump is preferably in driving connection with a pressure fluid motor and drives the pressure fluid motor preferably via a fluid Print buffer on. In this way, power fluctuations on both the output side of the pressure fluid motor and on the side of the hot gas engine can be better compensated. A stable operating condition is achieved which can quickly track load change changes and / or desired power changes. The fluid pressure pump and the pressure fluid motor are preferably compressed air units.

In a preferred embodiment, the pressure fluid motor is in driving connection with the fluid pressure pumps of a plurality of cylinder-piston units, which feed the pressure fluid motor to each other in parallel, optionally via a common fluid pressure buffer memory. The cylinder-piston units are expediently mutually identical modular units, so that in the modular system hot gas engines of different power can be constructed. As low it has proven in this context, when the cylinder-piston units are used in pairs and are controlled so that the displacer of the pair move in opposite phases. This leads to a more uniform utilization of the energy supply to the third-party drives. Especially if these are hydraulic third-party drives.

In order to achieve a sufficient mass balance during the movement of the pistons, it is preferably provided that, in the case of several cylinder-piston units, the third-party drives moving their displacer pistons are synchronously controlled with one another. When using pressure fluid drive cylinders, this can be achieved by synchronous control of the control valve assemblies. As far as the displacers are moved by electric motors via crank gear, this is most easily achieved by a common electric motor drives several crank gears. Conveniently, the arrangement is such that the displacers are moved in pairs in opposite phases. It is understood that the working pistons of several cylinder Piston units can be synchronized with each other, for example, by several working piston on a common crankshaft. Even if the working piston, which is preferred, are designed as freely oscillating working pistons, they can be synchronized with each other via pressure fluid cylinders coupled to the working pistons, for example in pairs, so that the forward movement of a working piston forcibly causes a reciprocation of the other working piston via a pressure fluid connection of the pressure fluid cylinders.

A particularly simple synchronization of a hot gas engine with a plurality of cylinder-piston units can be achieved if at least one pair of cylinder-piston units are provided, the working piston are designed to be free-swinging and their displacement piston moving third-party drives as double-acting pressure fluid drive cylinder, in particular hydraulic Drive cylinders are formed, the pressure chambers are connected to synchronous synchronization via connecting lines with one of the pressure chambers of the other pressure fluid drive cylinder of the pair. The connecting lines are expediently connected so that the displacer swing in push-pull, although a common mode vibration is possible. The pairwise mutual pressure fluid control of the cylinder-piston units can also be used in other than the above-described hot gas engines and has independent inventive significance.

During operation of the pressure fluid motor, the pressure fluid relaxes, and cools the engine, with the result that the Druekfluidmotor often has to be heated to keep it at a sufficient operating temperature. In a preferred embodiment it is therefore provided that the Druekfluidmotor is in heat exchange connection with the cooling arrangement of at least one piston-cylinder unit of the type described above, so that the dissipated via the cooling arrangement heat can be utilized for heating the expansion-cooled pressure fluid motor. The heat exchange connection can be a closed Heat transfer circuit with an example forcibly circulating heat exchange fluid include. In individual cases, it may also be sufficient if the pressure fluid motor is arranged in spatial proximity to the piston-cylinder unit, so that the heat exchange is achieved by heat conduction or by an air-convection flow.

In a preferred embodiment, the fluid pressure pump has a coaxially to the working cylinder section adjacent to this arranged pump cylinder section with an inlet valve and an outlet valve and connected to the working piston, sealed in the pump cylinder portion displaceable pump piston. The working cylinder section is in this case preferably tightly connected to the pump cylinder section. This has the advantage that the pump piston contributes to the sealing of the working piston and prevents leakage of working gas. This is particularly advantageous if instead of air as a working gas to increase the efficiency of helium is used. It is understood that the pump cylinder section for increasing the performance of the pump may have a larger inner diameter than the working cylinder section.

The working piston and the pump piston may be connected to a common piston rod, which is sealed on the working piston axially remote from the side of the pump piston in a cylinder head displaced. This improves the guidance of the working piston and the pump piston. The working piston can be resiliently biased on its side facing away from the first chamber by a compression spring to the first chamber, so that it "drives" the fluid pressure pump "flying." The compression spring can be easily accommodated in the piston rod common to the working piston and the pump piston ,

Independent inventive meaning also has a preferred embodiment in which the displacer is guided radially in the displacer cylinder portion and at its periphery to form the bypass path a plurality substantially axially extending, the two chambers has interconnecting grooves. The grooves increase the surface area of the bypass path so that the displacer piston as such has the effect of a regenerator without the need for additional heat storage means outside the displacer cylinder section. It is understood that in the grooves additional, the heat exchange surface increasing measures may be taken, such as wire nets or slats or the like may be inserted. The remaining between the grooves webs form guide surfaces, which lead the displacer in its displacement movement with relatively little play in the displacement cylinder section. These grooves preferably extend obliquely to the axial direction of the displacer piston, ie on helical lines around the piston axis, in order to prevent the webs from digging wear paths into the displacer cylinder portion.

The working gas is heated in the second chamber. In order to heat the working gas in the second chamber sufficiently quickly, even at high cycle frequency, it is provided in a preferred embodiment that the second chamber is closed on the side facing away from the displacer by a heatable by means of the heater cylinder head, which is a variety to the second chamber has open substantially axially extending channels. The channels may be formed by bores or slots and increase the heat exchange area available in the second chamber. In order to improve the gas circulation in the channels, the channels may be in fluid communication with each other at their ends remote from the displacer, so that pressure differences within the second chamber lead to gas flows in the channels. The gas circulation in the channels can also take place forcibly when the displacer piston, facing the cylinder head, carries at least one pump location, to which a respective pump chamber in fluid communication with the channels is assigned in the cylinder head. The measures for enlargement explained above the heat exchange effect in the second chamber also have independent inventive significance.

In the above-described embodiment of the cylinder head, the channels open to the second chamber are interconnected within the cylinder head. The working gas flow through the channels and thus the heat exchange performance can be significantly improved if the channels open to the second chamber are in the first chamber connecting the second chamber to the working gas bypass path. The cylinder head is expediently designed as a heat exchange body, which in addition to the leading working gas, the former channels in heat exchange contact with these stationary containing a heat transfer fluid second channels. This idea, too, has independent inventive significance. In such a heat exchange body, a very large number of first and second channels can be formed, which significantly increases the heat exchange performance of the cylinder head.

While the first channels to the displacer open into the second chamber, they can open on the side facing away from the displacer axially together in a connected to the bypass path collecting space of the cylinder head. This simplifies the construction of the cylinder head.

The second channels expediently run transversely to the first channels and are preferably arranged in a hot air path of the heater arrangement, in particular in the exhaust path of a burner. It is understood that not only gas but also liquids can be used as the heat transfer fluid. In transversely extending first and second channels, the working gas on the one hand and the heat transfer fluid on the other hand can be supplied particularly easily. In order to keep the flow resistance of the channels low, they are preferably designed as rectilinear channels. The channels may be cylindrical holes of the heat exchange body. However, in order to be able to approach comparatively large channel surfaces as closely as possible without impairing the mechanical stability of the heat exchange body, the first and / or second channels are preferred as flat in the channel cross-section Schlitzbzw. Splitting channels formed. The first channels are expediently each in groups in mutually parallel planes of alignment. The same applies to the second channels, so that the first and second channels are separated from each other only by flat partitions of comparatively small thickness and are supported on the webs remaining in the planes of alignment between adjacent channels. In order to improve the supporting effect, the first channels in adjacent planes are staggered with respect to each other. The same can also apply to the second channels.

The gap channels can also be incorporated into an integral heat exchanger body designed as a block. The heat exchange body may also be formed as a cast block, in which the channels are already poured in the casting process. Since the incorporation or pouring of a plurality of narrow channels can be complicated, it is provided in a preferred embodiment that the heat exchange body is formed as a stack of a plurality of plates, of which at least the plates lying in the interior of the stack on at least one of their flat sides to form the channels include a plurality of juxtaposed and spaced apart grooves, which are covered by an adjacent plate in the stack plate to form the channels. The grooves can be worked into the plates. But even here, the plates can be designed as castings, in which the grooves are already formed during the casting process. The plates can only be grooved on a flat side, the grooves in the stack being covered by the groove-free surface of the overlying plate. Alternatively, however, grooves may also be present on opposite sides of the plates. In the stack of plates, adjacent grooves may each add to or become channels groove-free plates and both sides grooved plates alternately inserted into the stack.

Since the first channels and the second channels are separated by plate walls, it is sufficient for the overall sealing of the channels against each other when in the stack adjacent plates are sealed against each other along their peripheral edges. Appropriately, this is done by a tight weld, which also attaches the plates in the stack at the same time.

Expediently, the heat exchange body is a part produced separately from the rest of the cylinder head. The heat exchange body can be made in this way from a good heat conducting material, while the remaining part of the cylinder head provides for its mechanical stability. The cylinder head is preferably designed as a cast part, in which the heat exchange body produced as a separate part is cast. The cylinder head provides for a cross-sectional adaptation seen in the axial direction of the displacer piston. While the displacer usually has a circular cross section, the heat exchange body preferably has a rectangular cross section, in particular a square cross section. The edge lengths of the rectangular cross section are larger than the diameter of the circular cross section of the displacer to increase the heat exchange capacity of the heat exchange body. The cylinder head forms here on the side facing the displacer in the over the circular cross-section protruding corner regions of the rectangular cross-section leading into the second chamber collecting chambers for the working gas.

In the following the invention will be explained in more detail with reference to a drawing. Hereby shows:

1 shows an axial longitudinal section through a cylinder-piston unit of a hot gas engine operating in accordance with a Stirling cycle; FIG. 2 shows an axial cross section through a displacement piston of the cylinder-piston unit, seen along a line M-II in FIG. 1; FIG.

3 shows an axial cross section through the cylinder head of a displacement cylinder section of the cylinder-piston unit, as seen along a line III-III in FIG. 1;

FIG. 4 illustrates a motor assembly constructed using multiple cylinder-piston units; FIG.

5 shows an axial longitudinal section through a variant of the cylinder-piston unit from FIG. 1;

6 shows an axial longitudinal section through a further variant of the cylinder-piston unit.

Fig. 7 is a perspective view of a heat exchange body of the cylinder-piston unit of Fig. 6 and

8 shows a hydraulic control for a pair of cylinder-piston units joined together to form a working unit according to FIG. 6.

The illustrated in Figures 1 to 3 hot gas engine comprises a cylinder-piston unit 1 with a working cylinder section 3, in which a sealed by a seal 5 against the inner shell 7 of the working cylinder section 3 working piston 9 is displaceable. A displacement cylinder section 11 adjoins the working cylinder section 3 coaxially, in which in turn a displacer piston 13 is axially displaceable. The displacer cylinder section 11 is closed on the side remote from the working cylinder section 3 by a cylinder head 15 and, together with the working cylinder section 3 and the working piston 9, defines a generally with the 17th designated gas process space whose volume corresponding to the displacement movement of the working piston 9 between the maximum volume shown in Figure 1, wherein the working piston 9 is the displacer cylinder section 11 located away and a minimum volume at which the working piston 9 that shown in Figure 1 at 9 ¹ , the displacer cylinder 11 adjacent to the dead center position varies.

The displacement piston 13 divides the gas process chamber 17 into two chambers 19 and 21 whose volume ratio changes depending on the position of the displacement piston 13. In the dead center position of the displacer piston 13 shown in FIG. 1, the chamber 19 defined by the working piston 9 and the displacer piston 13 is maximum, while the chamber 21 located on the side of the displacer piston 13 facing away from the working piston 9 is minimal. If the displacement piston 13 is displaced into the other dead center position of the displacer piston 13 indicated at 13 ', the volume of the chamber 19 is minimal and that of the chamber 21 is maximum.

The gas process chamber 17 is filled with a closed volume of pressurized working gas, for example air, but preferably helium. Between the inner jacket 23 of the displacer cylinder section 11 and the circumference of the displacer 13, a bypass path 25, explained in more detail below, is provided, via which the working gas is displaced out of the chamber 19 into the chamber 21 and back, depending on the stroke position of the displacer piston 13.

The displacer 13 is forcibly reciprocated via an external drive, here in the form of a hydraulic cylinder 27 forcibly and discontinuously between its two dead center positions. The hydraulic cylinder 27 is determined by a subsequently explained in more detail with reference to FIG 4 control with a forcibly Clock frequency and / or forcibly controlled clock phase controlled. The hydraulic cylinder 27 is designed as a double-acting cylinder and arranged on the displacer cylinder section 11 axially facing away from the working cylinder section 3. In the hydraulic cylinder 27, whose hydraulic connections are shown at 29, 31, a piston 33 is coaxially displaceable coaxially to the displacer 13, which is coupled via a at 35 against the working process space 17 sealed, displaceable by the piston 9 extending piston rod 37 with the displacer 13 , Position sensors 39 detect the end positions of the piston 33 and thus the dead center positions of the displacer 13th

The chamber 21 and at least part of the displacer cylinder portion 11 delimiting it protrude into a heating space delimited by a housing 41 which heats the working gas in the chamber 21. The displacer cylinder portion 11 and its cylinder head 15 are provided on the outer sides thereof for enlarging the heat exchange surfaces with ribs 45 or the like. The heating space 43 is charged with hot gas, for example, from a gas or oil burner. It is understood that any other heat source is suitable. In particular, waste heat from another process can be used. The waste heat can optionally also be supplied by direct thermal contact with the displacer cylinder section 11 or the cylinder head 15.

The chamber 19 of the working process chamber 17 formed between the displacer piston 13 and the working piston 9 is enclosed by a cooling arrangement 47 which cools the working gas displaced by the displacer piston 13 into the chamber 19. In the illustrated embodiment, the cooling arrangement 47 is formed as a fluid cooling jacket, which encloses the working cylinder section 3 and a part of the displacement cylinder section 11. The cooling fluid, which is preferably a cooling fluid, for example water, is supplied or removed via ports 49, 51. The cooling jacket 47 extends in the illustrated Embodiment substantially over the entire stroke of the working piston 9 in order to avoid sealing problems on the piston.

The above-described cylinder-piston unit 1 operates in a Stirling cycle. In the dead center positions of the displacement piston 13 and of the working piston 9 shown in FIG. 1, the displacement piston 13 has displaced the working gas heated in the chamber 21 into the chamber 19 in which it is cooled and, accordingly, the pressure in the working gas decreases. A between the piston 9 and a fixed to the working cylinder section 3 stop, here clamped to the hydraulic cylinder 27, the piston rod 37 enclosing helical compression spring 53 moves the piston 9 in its the volume of the chamber 19 reducing dead center 9 '. In a next step of the Stirling cycle process, the hydraulic cylinder 27 displaces the displacer 13 into the dead center position 13 ', wherein the cooled working gas is displaced from the chamber 19 via the bypass path 25 into the chamber 21, in which it is reheated. This increases in the working process space 17, the pressure of the working gas and the working piston 9 is pushed under compression of the compression spring 53 and under work again in the dead center position shown in Figure 1. The Stirling cycle begins again.

In the illustrated embodiment, the working piston 9 forms a free-swinging piston which is directly coupled to a fluid pressure pump. The fluid pressure pump may be a hydraulic pump. In the present case, however, an air-pressure pump 55 is provided, the cylinder 57 fixed on the displacement piston 13 axially opposite side and at 59 sealed equiaxial to the working cylinder section 3 to this. In the cylinder 57, a piston 61 is displaceable sealed, which is connected via a sleeve-shaped, the compression spring 53 enclosing the piston rod 63 fixed to the working piston 9. The piston rod 63 is in a centric projection 65 of a cylinder 57 on the working cylinder section 3 far side final cylinder head 67 sealed slidably guided. The projection 65 carries position sensors 69 of the control explained in more detail below, which detect the dead center positions of the piston rod 63 and thus of the working piston 9. In the cylinder head 67, there are further provided an air inlet port 71 provided with an intake valve and an exhaust port 73 provided with an air exhaust valve. The hydraulic cylinder 27 is screwed into the piston-remote end of the projection 65.

The clock rate at which the hydraulic cylinder 27 moves the displacer piston 13 determines the operating frequency of the working piston and thus the pumping power of the air pressure pump 55. Since the working piston 9 can oscillate freely, its stroke can be adapted to the energy supplied in accordance with the Stirling cycle , which leads to a stable operation. It is also advantageous that the cylinder 57 of the air pressure pump 55 sealed connects to the working cylinder section 3, since then the piston 61 in addition to the seals 5 of the working piston 9 reduces pressure losses of working gas, which is particularly advantageous for helium as working gas. In particular, the gap 71 between the working piston 9 and the piston 61 can be kept at a certain overpressure, which additionally counteracts a working gas loss. The cylinder 57 can, as shown in Figure 1 have a larger inner diameter than the working cylinder section 3, whereby on the one hand, the pumping power of the air pressure pump 55 can be increased and on the other hand in the course of the piston movement, an overpressure in the gap 71 is generated.

As shown in Figures 1 and 2, the displacer 13 is provided on its outer periphery with a plurality of circumferentially distributed helically arranged grooves 75 with interposed, also helical ridges 77. The webs 77 lead with little play the displacer piston 13 at the indicated in Figure 2 at 79 inner surface of the displacer cylinder section 11, while the entirety of the grooves 75 forms the bypass path 25. The grooves 75 increase the surface of the displacer 13, which thus forms a conventional regenerator in Stirling machines. The regenerator stores a portion of the heat of the working gas as it is displaced into the cooled chamber 19 by the displacer 13 from the chamber 21 in which it was heated. If the cooled working gas is displaced from the chamber 19 back into the chamber 21, the thus cached heat to improve the efficiency of the machine is returned to the working gas. It is understood that the regeneration performance is determined by the number and depth of the grooves 75. In addition, 75 further heat exchange surfaces, for example in the form of slats or a wire mesh or the like may be provided in the grooves. It is further understood that the regenerator can also be provided in a bypass line connecting the chambers 19 and 21 outside the displacement cylinder section 11.

For high-speed machines, the residence time of the working gas in the chamber 21 is relatively short. In order nevertheless to ensure adequate heat transfer to the working gas, the cylinder head 15 is on its side facing the displacer 13, as shown in Figures 1 and 3, with a plurality of axially extending, the displacer 13 toward open channels 81, here in the form of holes , Mistake. The channels 81 are connected at their ends facing away from the displacer 13 by connecting channels 83 with each other and with a centric chamber 85, in which a projecting from the displacer 13 Pumpfortsatz 87 in the cylinder head 15 adjacent dead center position of the displacer 13 is immersed. The Pumpfortatz 87 provides during the approach of the displacer 13 to the dead center position for a working gas flow in the channels 81, 83 and thus due to the increased heat exchange surfaces for improving the heating of the working gas. If necessary, the chamber 85 and the pump set 87 can be omitted. The channels 81 are arranged in rows, with the connecting channels 83 each of the channels 81 of two adjacent Cut rows. In this way, the remaining material for the heat transfer in the base of the cylinder head 15 material cross section can be made sufficiently large.

In the illustrated embodiment, the piston 9 is designed as a free-swinging piston. It is understood that the working piston 9 but also forcibly coupled with an output, such as a crank output.

In the illustrated embodiment, the hydraulic cylinder 27 is disposed on the side facing away from the displacer 13 of the working piston 9. It is understood that the hydraulic cylinder 27 may also be arranged on the side of the cylinder head 15. Although a closed working piston 9 can be used in this way, the seals which are then required for sealing the piston rod of the displacement piston 13 are arranged on the hot side of the displacement cylinder section 11, which can lead to sealing problems.

The illustrated with reference to Figures 1 to 3 hot gas engine allows the generation of a pressurized fluid flow, in this case of compressed air. The piston-cylinder unit 1 is in this case designed as a module which is functional on its own. FIG. 4 shows a motor arrangement 89 constructed using a plurality of such cylinder-piston units or modules. The motor arrangement comprises at least one pair of cylinder-piston units 1 explained with reference to FIGS. 1 to 3, which are controlled by an electronic control unit 91 Hydraulic control valve 93 are connected to a hydraulic pressure source 95. The hydraulic pressure source 95 conventionally comprises a hydraulic pump 97 with a pressure relief valve 99 and a filter 101 in a return line. The control valve 93 is formed as a switching valve, which connects the pressure output of the hydraulic pump 97 alternately with the pressure ports 29 of the double-acting hydraulic cylinder 27, so that alternately the Displacer 13 are moved away from Arbeitskolbeπ 9 away. The control valve 93 connects the pressure input 29 of each not connected to the high pressure output of the hydraulic pump 97 port 29 with the leading through the filter 101 to the hydraulic tank 103 return line. The hydraulic cylinders 27 of the pair are pressurized in this way in antiphase. The opposite direction of actuation associated ports 31 of the hydraulic cylinder 27 are connected in pairs via one line 105 to each other, wherein the line 105 associated system is also filled with pressurized hydraulic fluid. The actively actuated by the pressure of the hydraulic pump 97 hydraulic cylinder 27 ensures in this way for the retrieval of each other hydraulic cylinder. The position sensors 39 and 69 are connected to the controller 91 and provide the synchronization of the piston movements.

The piston-cylinder units 1 of FIG. 4 differ essentially from the unit of FIGS. 1 to 3 only in that the two units 1 are assigned a common housing 41 forming the heating space 43.

The antiphase working air pressure pumps 55 suck in ambient air via connected to the air inlets 71 air filter 107 and are connected via their compressed air outlets 73 parallel to each other to a compressed air buffer memory 109, from which a compressed air motor 111 is fed. The air motor 111 has a housing 113 in which a cylinder rotor 115 is rotatably mounted with a plurality of cylinders 117 arranged distributed in the circumferential direction. When the rotor rotates, the pairs of pistons coupled via eccentric disks 119 to a crankshaft 121 drive the crankshaft 121 in a rotating manner. The compressed air supplied on the outer circumference of the rotor via an inlet gap 123 relaxes in the course of the rotational movement of the rotor 115 and leaves the compressed air motor 111 via an outlet gap 125. Constructive details of such a compressed air motor are described in EP 0 477 256 B1, however Place of compressed air is used by ignition expanding fuel-air mixture. Further details are described in DE 196 11 824 C1 by means of an engine, which, however, utilizes pressurized steam instead of compressed air as working gas.

It is understood that other types of air motors may be used, such as engine turbines or the like. It is also understood that the system can also operate on a hydraulic basis when the pressure accumulator 109, the motor 111 and the fluid pumps 55 are suitable for delivering a hydraulic fluid.

Figure 4 shows the engine system 89 with only two cylinder-piston units 1. It is understood that more than two units can be provided, as indicated by lines at 127. Although for mass balance and vibration freedom of the system out of phase working pairs of such units are preferred, the number of units may also be chosen to be odd.

In compressed air motors of the above type, the compressed air expands in the course of the rotor rotation. Accordingly, the air motor 111 is cooled. Accordingly, the air motor 111 must be externally heated when a desired operating temperature is to be maintained.

In the embodiment of Figure 4, this is achieved in that the in

Cooling jacket 47 of the piston-cylinder units 1 in the cooling of the chamber 19 dissipated heat in a cooling circuit provided in the housing 113, indicated at 129 heat exchanger for heating the

Motors 111 is supplied. For this purpose, the heat exchanger 129 is connected to the connections 49, 51 in a closed heat exchanger circuit. It is understood that the heat exchanger circuit may optionally comprise a circulation pump.

In the following, variants of the cylinder-piston unit 1 explained with reference to FIGS. 1 to 3 will be described. Equally effective components are designated by the reference numbers of Figures 1 to 3. To explain these components, reference is made to the description of Figures 1 to 3. Unless otherwise stated, the variants of the cylinder-piston units can be operated with a controller or a motor according to Figure 4.

The cylinder-piston unit 1 of Figure 5 differs from that of Figures 1 to 3 essentially only in that instead of the double-acting hydraulic cylinder 27 and its components 29 to 33 and 39, the piston rod 37 of the displacer 13 via a connecting rod 131st is connected to a driven by an electric motor 133 crank 135. The crank far end of the connecting rod 131 engages a carriage 137, which is guided coaxially to the piston rod 37 on a guide 65 connected to the guide 139 slidably. The electric motor 133, which is preferably a stepper motor, is controlled by an electronic controller, similar to the controller 91 of FIG. 4, discontinuously corresponding to the two dead center positions of the displacer piston 13. It is understood that the cylinder-piston unit of Figure 5 can be operated in the engine system 89 of Figure 4. Again, the electric motor 133 can be used for the control of a plurality of cylinder-piston units 1, for example by 133 several crankshaft arms are provided on the output shaft of the electric motor. Again, the crankshaft arms, as indicated at 135 'in Figure 5 by 180 degrees offset from each other to achieve pairwise out of phase operation of the units 1. It is understood that the electric motor 133 together can drive the displacers of more than two units 1. It is also understood that instead of an electric motor, a pneumatic or hydraulic motor with a rotating crank output can be used. Instead of a crank output and a cam output or the like can be used in the above-described variants, as far as the cam lift meets the desired Verdrängerkolbenhub. FIG. 6 shows a variant of the cylinder-piston unit 1 explained with reference to FIGS. 1 to 3, which differs from this unit essentially in that the two chambers 19, 21 of the working process space 17 are replaced by a regenerator 141 arranged outside the displacement cylinder section 11, which is arranged in a bypass path formed by lines 143, 145 for the working process gas, are interconnected. The bypass path is hereby guided by a heat exchange body 147 which is contained in the cylinder head 15 and heats the working gas. The remaining construction of the cylinder-piston unit 1 corresponds to the variant of Figures 1 to 3.

While the regenerator 141 is conventional in design and may be divided into a heating zone and a cooling zone, for example, the heat exchange body 147 allows efficient heating of the working gas in the chamber 21.

The heat exchange body 147 includes a plurality in the direction of displacement of the displacer 13 rectilinearly extending first channels 149 which are open on the side of the displacer 13 to the chamber 21 and on the side remote from the displacer 13 in one of a roof wall 151 of the cylinder head 15 limited with the shunt line 145 connected collecting space 153 open. Transverse to the channels 149 and separate from these channels, a plurality of second channels 155 extends through the cylinder head 15 and the heat exchange body 147 transversely to the displacement direction of the displacer 13, here perpendicular to the plane of the figure 6. The channels 155 are optionally on collecting spaces from outside the cylinder head 15 accessible so that they can be traversed by hot gas or hot liquid for the heating of the working gas. The channels 155 are expediently arranged in the exhaust path of a burner or the like.

FIG. 7 shows details of the heat exchange body 147. The channels 149 and 155 are formed as gap channels which are flat in cross-section and lie with their flat sides next to one another and only separated by webs 157 and 159 extending along the channels, in mutually parallel alignment planes. The narrow side width of the channels lying in the exhaust path 155 is hereby slightly larger than the narrow side width of the channels 149. Flattening levels with channels 149 alternate here with planes of flattening of the channels 155, so that the channels 149 are separated from the channels 155 by narrow flat walls 161. The narrow side width of the channels 149 is a few millimeters, z. B. 1 to 3 mm.

The heat exchange body 147 may consist of an integral block of material of a highly conductive material, such as a metal alloy, in which the channels 149, 155 are incorporated. Since, in particular, the channels 149 have a very small narrow side width, for example only 1 mm, the production of an integral heat exchanger body can be complicated. In order to simplify the production of the heat exchange body 147, this is made up of a stack of plates 163 which on their opposite flat sides in the direction of the channels 149 on the one hand and 155 on the other hand extending grooves 165 and 167, respectively. In the stack of plates 163, the grooves 165 of adjacent plates 163 and the grooves 167 of adjacent plates 163 are opposite and limit in this way the channels 149 and 155. The plates 163 are flat on each other and are only along their peripheral edges by welds 169, for example Electron welds tightly connected.

It is understood that the channels 149, 155 can also be realized by a different division of the grooves 165, 167. For example, the plates 163 may only be provided on one of their flat sides with grooves 165 or 167, which is then supplemented by the groove-free flat side of the adjacent plate 163 to the channel 149 and 155, respectively. Also, both sides grooved plates 163 and total groove-free plates in alternately follow each other in the stack.

Conveniently, the plates 163 are molded parts with embedded grooves. Also, in the cylinder head 15 is preferably a cast molding, wherein expediently the heat exchange body 147 prepared in advance separately and then poured in the production of the cylinder head 15 with. The materials of the heat exchange body 147 and the cylinder head 15 may be different and selected according to the desired thermal conductivity and mechanical strength, respectively.

Seen in the direction of displacement of the displacer 13 has this circular cross section, while the heat exchange body 147 has the simpler manufacturability because of square cross-section. The edge length of the square cross section is in this case selected to be approximately equal to the diameter of the displacer piston 13. As FIG. 6 shows, collecting chambers 171 are provided in the corner regions, which exceed the circular cross section of the displacer cylinder section 11, adjacent to the displacer piston 13, which also allow these regions of the heat exchanger body 147 to be used for heating the working gas.

The hot gas engine explained with reference to FIGS. 6 and 7 is likewise designed as a module, similar to the hot gas engine of FIGS. 1 to 3, and is suitable for constructing a motor arrangement using a plurality of such modules, as has already been explained with reference to FIG. For controlling the cylinder-piston units 1 or modules, in turn, a control valve controlled by an electronic control valve may be provided, as shown in FIG. FIG. 8 shows a simplified embodiment which permits a pairwise synchronization of two cylinder-piston units 1 without a hydraulic pressure source. FIG. 8 shows the double-acting hydraulic cylinders 27 of the pair of cylinder-piston units 1, which are not shown in more detail. 37 denotes the piston rods connected to the displacement piston 13, which as already explained with reference to FIGS. 1 to 3, but displaceably pass through the working pistons 5 of the units 1. The hydraulic connections 29 of the displacers remote pressure chambers are connected via a connecting line 173 together. The ports 31 of the displacer adjacent pressure chambers connects a line 175. The pressure chambers and connecting lines 173, 175 are completely filled with hydraulic fluid. The displacers of the two cylinder-piston units are thus controlled in push-pull.

As explained with reference to Figures 1 to 3 and 6, the working piston 5 can freely swing against the force of the compression springs 53. On the displacer piston 13 far side of the piston 33, a compression spring 177 is arranged in the hydraulic cylinder 27. The compression spring 177 serves as a stop buffer, which absorbs the displacer in one of its end positions. A on the displacer side facing the piston 33 arranged in the hydraulic cylinder 27 compression spring buffers the displacer in its other end position. The position of the compression spring 177 can be adjusted by means of a set screw 181. With a sufficiently large spring travel length of the compression springs 177, these compression springs can also be utilized for the complete recovery of the displacer, wherein by adjusting the bias and the swing characteristics of the displacer can be adjusted.

It is understood that the arrangement of Figure 8 can also be used for cylinder-piston units according to Figures 1 to 3 and in conjunction with a motor according to Figure 4.

Claims

claims

1. Hot gas engine comprising:

- A cylinder-piston unit (1) having a working cylinder section (3) in which a working piston (9) is guided displaceably sealed and a Verdrängerzylinderabschnitt (11), in which a displacer piston (13) is displaceably guided, wherein the Verdrängerzylinderabschnitt ( 11), the working cylinder section (3) and the working piston (9) together define a closed, filled with a working gas gas process space (17) whose volume varies according to the sliding movement of the working piston (9), and the displacer (13) the gas process space (17 ) in two chambers (19, 21), of which a first (19) of the two chambers (19, 21) of the displacer piston (13) and the working piston (9) is limited and wherein the two chambers (19, 21) are connected to one another via a bypass path (25) for the working gas bridging the displacer piston (13),

a cooling arrangement (47) for cooling the working gas in the first (19) of the two chambers (19, 21),

a heater arrangement (41, 43, 45) for heating the

Working gas in a second (21) of the two chambers (19, 21),

a drive assembly (27, 133, 135) oscillating reciprocatingly the displacer piston (13) in the displacer cylinder portion (11) and

a driven arrangement (55) connected to the working piston (9), characterized in that the drive arrangement of the displacement piston (13) is designed as a controllable external drive (27; 133, 135) whose movement stroke is forcibly changeable relative to the movement stroke of the working piston (9).

2. Hot gas machine according to claim 1, characterized in that the external drive via a piston rod (37) with the displacer (13) connected to the pressure fluid drive cylinder (27), via a control of a (91) controlled control valve assembly (93) pressurized fluid with forcibly predetermined

Clock frequency and / or forcibly predetermined clock phase can be fed.

3. Hot gas machine according to claim 2, characterized in that the pressure fluid drive cylinder (27) has a double-acting

Drive cylinder is.

4. hot gas machine according to claim 2 or 3, characterized in that the pressure fluid drive cylinder (27) is a hydraulic drive cylinder.

5. Hot gas machine according to claim 1, characterized in that the external drive via a crank gear (133) with the displacer (13) connected to the electric motor (133) whose output speed and / or output phase by means of a

Control (91) is forcibly beforehand.

6. Hot gas machine according to one of claims 2 to 5, characterized in that the controller (91) at least one of a predetermined

Movement position of the third-party control (27) is detected associated position sensor (39).

7. Hot gas machine according to one of claims 1 to 6, characterized in that the displacement cylinder section (11) and the working cylinder section (3) are coaxially arranged side by side and the foreign drive (27; 133, 135) on the displacement cylinder section (11) axially facing away from side of the working cylinder section (3) is arranged.

8. Hot gas machine according to one of claims 1 to 7, characterized in that a plurality of cylinder-piston units (1) are provided, whose

Displacement piston (13) moving third-party drives (27, 133, 135) are synchronously controlled with each other.

9. hot gas machine according to claim 1 or the preamble of claim 1, characterized in that at least one pair of cylinder-piston units (1) are provided, the working piston (5) are designed to be free-running and their displacement piston (13) moving third-party drives (27 ) are formed as a double-acting pressure fluid drive cylinder, in particular hydraulic drive cylinder whose pressure chambers for synchronization synchronization via connecting lines (173, 175) are each connected to one of the pressure chambers of the other pressure fluid drive cylinder of the pair.

10. Hot gas engine according to one of claims 1 to 9 or the preamble of claim 1, characterized in that the output arrangement comprises a driven by the working piston fluid pressure pump (55).

11. hot gas machine according to claim 10, characterized in that the fluid pressure pump to the working cylinder section (3) coaxially next to this arranged pump cylinder section (57) with an inlet valve (71) and an outlet valve (73) and a comprising with the working piston (9), in the pump cylinder section (57) sealed displaceable pump piston (61).

12. Hot gas machine according to claim 11, characterized in that the working cylinder section (3) with the pump cylinder section (57) is tightly connected.

13. hot gas machine according to claim 11 or 12, characterized in that the pump cylinder portion (57) has a larger inner diameter than the working cylinder portion (3).

14. Hot gas machine according to one of claims 9 to 13, characterized in that the working piston (9) and the pump piston (61) with a common

Piston rod (63) are connected, which is sealed on the working piston (9) axially facing away from the pump piston (61) in a cylinder head (67) slidably.

15. Hot gas machine according to one of claims 9 to 14, characterized in that the working piston (9) is resiliently biased on its from the first chamber (19) axially facing away from a compression spring (53) to the first chamber (19) towards.

16. Hot gas machine according to one of claims 9 to 15, characterized in that the fluid pressure pump (55) is an air pressure pump.

17. hot gas machine according to one of claims 9 to 16, characterized in that the fluid pressure pump (55) is in driving connection with a pressure fluid motor (111).

18. hot gas machine according to claim 17, characterized in that the drive connection between the fluid pressure pump (55) and the pressure fluid motor (111) includes a fluid pressure buffer memory (109).

19. Hot gas engine according to claim 17 or 18, characterized in that the pressure fluid motor (111) is in driving connection with the fluid pressure pumps (55) of a plurality of cylinder-piston units (1).

20. hot gas machine according to claim 19, characterized in that the cylinder-piston units (1) are formed as mutually identical modular units.

21. Hot gas engine according to claim 19 or 20, characterized in that the controllable third drives (27; 133, 135) of at least one pair of cylinder-piston units (1) are controlled so that the displacement piston (13) of the pair move in opposite phase , 0

22. Hot gas engine according to one of claims 17 to 21, characterized in that the pressure fluid motor (111) is in heat exchange connection with the cooling arrangement (47) of at least one piston-cylinder unit (1). 5

23. hot gas machine according to one of claims 1 to 22 or the preamble of claim 1, characterized in that the displacer (13) in the Verdrängerzylinderabschnitt (11) is guided radially and at its periphery to form the o bypass path (25) a plurality in Has substantially axially extending, the two chambers (19, 21) interconnecting grooves (75).

24. hot gas machine according to claim 23, characterized in that the number of grooves (75) and their depth are chosen so that the grooves (75) form a regenerator.

25. Hot gas machine according to claim 23 or 24, characterized in that the grooves (75) extend obliquely to the axial direction of the displacement piston (13).

26. Hot gas machine according to one of claims 1 to 25 or the preamble of claim 1, characterized in that the second chamber (21) on the said displacer (13) axially facing away by a means of the heater assembly (41, 43) heatable cylinder head ( 15) is completed, which has a plurality of the second chamber (21) open, substantially axially extending channels (81).

27. hot gas machine according to claim 26, characterized in that at least a part of the channels (81) at their the displacer (13) axially opposite ends are in flow communication with each other.

28. Hot gas machine according to claim 27, characterized in that the channels (81) via transversely extending channels (83) are in fluid communication with each other.

29. Hot gas engine according to claim 27 or 28, characterized in that the displacement piston (13) axially facing the cylinder head (15) carries at least one pump location (87), in which the cylinder head (15) in each case one in fluid communication with the channels (81, 83) is assigned standing pump chamber (85).

30. Hot gas machine according to claim 26, characterized in that the channels (149) open to the second chamber (21) are in the bypass passage (143, 145) for the working gas connecting the first chamber (19) to the second chamber (21), and in that the cylinder head (15) acts as a heat exchange body (147 ) is formed, in addition to the working gas leading, the former channels

(149) contains in heat exchange contact with this standing, a heat transfer fluid leading second channels (155).

31. hot gas machine according to claim 30, characterized in that the first. Channels (149) on the said displacer (13) axially facing away from one another in a connected to the bypass path (143, 145) collecting space (153) of the cylinder head (15) open.

32. Hot gas machine according to claim 30 or 31, characterized in that the second channels (155) extend transversely to the first channels (149) and are arranged in a hot air path of the heater arrangement, in particular in the exhaust path of a burner.

33. hot gas machine according to one of claims 30 to 32, characterized in that the first (149) and / or second (155) channels are rectilinear channels.

34. Hot gas machine according to one of claims 30 to 33, characterized in that the first (149) and / or second (155) channels are formed as flat in the channel cross-section channels.

35. hot gas machine according to one of claims 30 to 34, characterized in that the heat exchange body (147) as a stack of a plurality of plates (163) is formed, of which at least lying in the interior of the stack plates (163) on at least one of its flat sides to form the channels (149, 155) a plurality of juxtaposed and spaced apart grooves (165, 167) containing by a stack adjacent plate (163) to form the channels (149, 155) are covered.

36. hot gas machine according to claim 35, characterized in that in the stack adjacent plates (163) are sealed against each other along their peripheral edges, in particular by a tight weld (169) are fastened together.

37. hot gas machine according to claim 35 or 36, characterized in that the plates (163) are formed as castings.

38. hot gas machine according to claim 30 to 37, characterized in that the cylinder head (15) is designed as a casting, in which the heat exchange body (147) is cast as a separately manufactured part.

39. hot gas machine according to one of claims 30 to 38, characterized in that seen in the axial direction of the displacer (13) of the displacer piston (13) circular cross-section and the heat exchange body (147) has a rectangular cross-section, in particular square cross-section.

40. hot gas machine according to claim 39, characterized in that the contour length of the rectangular cross section is greater than the diameter of the circular cross section and the cylinder head (15) on the

Displacement piston (13) side facing in the over the circular cross-section protruding corner regions of the rectangular cross-section leading into the second chamber collecting spaces (171).