EP3402973B1 - Method for operating an axial piston motor, and axial piston motor - Google Patents

Description

The invention relates to a method for operating an axial piston motor, in which fuel and compressed fuel burned continuously to working fluid in a combustion chamber and successively working cylinders is fed, in which working piston back and forth, which in turn drive an output and compressor pistons, which in compressor cylinders out and run here, in which the combustion medium is compressed, wherein the fuel medium is sucked in via compressor inlet valves and the compressed fuel medium is supplied via compressor outlet valves of the compressor cylinders of the combustion chamber. Likewise, the invention relates to an axial piston motor with a continuous compressed combustion medium and fuel combustion medium combustion chamber, with working cylinders, which are connected by means of cyclically openable and closable weft connections with the combustion chamber and in which working piston reciprocate, with compressor cylinders, in which compressor piston out and at least one combustion medium supply line leading from compressor discharge valves of the compressor cylinders to the combustion chamber, at least one of the compressor discharge valves having a closure member opening away from the compressor cylinder and cooperating with a valvetrain.

Such operating methods or axial piston motors are for example from the EP 1 035 310 A2 or from the WO 2011/00943 A2 known. This reveals the EP 1 035 310 A2 a ceramic ball, which is pressed by the pressure prevailing in a pressure chamber or in a Brennmediumzuleitung pressure against its valve seat and serves as a closure part of a compressor outlet valve. In this way, the outlet valve remains closed as long as the pressure in the compressor piston is below the pressure in the pressure chamber or under the pressure of the corresponding Brennmediumzuleitung. If the pressure in the compressor cylinder rises above the pressure in the combustion medium supply line or the pressure chamber, then the closure part of the compressor outlet valve formed by the ceramic ball opens and strikes against an adjusting screw. This opens the way into the pressure chamber. Also the WO 2011/009453 A2 discloses such a passive control of the compressor outlet valve with a valve cover designed as a hemisphere, which interacts with a Ventildeckelandruckfeder, so ultimately also this compressor outlet valve on the pressure difference between the compressor cylinder and Brennmediumzuleitung is controlled, the spring force of the Ventildeckelandruckfeder ultimately acts only parallel to this pressure difference.

The DE 602 25 683 T2 discloses a desmodromic valve control in which a valve is forcibly opened and closed.

It is an object of the present invention to provide a method for operating an axial piston motor and an axial piston motor, in which the compression takes place as effectively as possible.

The object of the invention is achieved by a method for operating an axial piston motor and an axial piston motor having the features of the independent claims. Further, possibly also independent thereof, advantageous embodiments can be found in the subclaims and the following description.

Thus, the most effective possible compression in a generic method for operating an axial piston motor, if this is characterized in that at least one of the compressor exhaust valves positively controlled closed and opened via a built-up in the respective compressor cylinder compressor pressure. In this way, the combustion medium from the compressor cylinder is supplied to the combustion chamber, and in the compressor cylinder is sufficient to find compressor pressure, while it can be ensured via the positively controlled closure that no fuel medium flows back into the compressor cylinder, which would accordingly lead to losses.

It goes without saying that such a process control is also suitable for a multi-stage compression in which the fuel leaving the compressor is not directly the combustion chamber but indirectly via a further compression stage, such as another compressor cylinder, the combustion chamber is supplied.

In the method described above, compaction and work are separated, so that a compression can be carried out at the lowest possible temperatures.

Preferably, the closing operation of the at least one of the compressor discharge valves is initiated before the associated compressor piston reaches its top dead center. Although compressed at this time then still compressed fuel medium from the compressor cylinder to the combustion chamber. In the vicinity of the upper Tonpunktes but this is done only with a relatively low volume mass flow, so that by the closing compressor outlet valve due smaller valve throughput is not critical and the flow impeded only slightly.

Preferably, the closing operation of the at least one of the compressor outlet valves is initiated at the latest 5 °, preferably at the latest 7 °, before the associated compressor piston reaches its top dead center.

It should be noted in particular that to close the compressor outlet valve, the closure part of the compressor outlet valve has to accelerate and travel a certain distance until finally the compressor outlet valve is closed. By the closing process is initiated in time, it can be ensured that the corresponding compressor outlet valve is closed in good time, especially taking into account tolerances.

In this case, the forced or positively controlled closing, after the closing operation is initiated, under certain circumstances by the moving mass of one of the compressor exhaust valves ultimately made, which in particular allows compliance with any tolerances, especially since the compressor outlet is kept closed by the pressure difference, and the associated Compressor piston has reached its top dead center. In this respect, it is not absolutely necessary that the corresponding compressor outlet valve is actively pressed down to the point at which it is tightly closed or is in contact with a pressure system. In this respect, it is advantageous if at least one of the compressor outlet valves is freely closed by its own mass, virtually ballistic, after the initiation of the closing process.

Accordingly, it is advantageous if the at least one of the compressor outlet valves is closed when the associated compressor piston reaches its top dead center. As a result, any possible backflow of combustion medium from the combustion medium supply line, which - as already indicated above - can also be interrupted by a second compressor stage, can be prevented in the respective compressor cylinder. In this way, since immediately after reaching the top dead center of the compressor piston acts suction, a loss of compressed fuel medium can be reduced to a minimum or avoided altogether.

Due to the fact that the at least one of the compressor outlet valves is opened above the compressor pressure which builds up into the respective compressor cylinder, it is possible immediately if there is sufficient pressure in the compressor cylinder, combustion medium are conveyed to the combustion chamber.

So that a corresponding, pressure-controlled opening of the corresponding compressor outlet valve can be reliably ensured, it is advantageous if the at least one of the compressor outlet valves is released before the compression process in the respective compressor cylinder. This can happen, for example, already during the suction. In particular, this can already be done at the latest 12 °, preferably at the latest 10 °, after the associated compressor piston has reached its top dead center, since in the end the pressure difference between the fuel supply line and the compressor cylinder ensures that the corresponding compressor outlet valve remains tightly closed.

In particular, the at least one of the compressor outlet valves can be driven mechanically, which allows a particularly precise and structurally simple to implement drive form.

It is preferable if the at least one of the compressor outlet valves is driven in synchronism with the output of the axial piston motor, it being understood that, depending on the respective operating state, the phases between the output of the axial piston motor and the drive of the compressor outlet valve may be adapted.

In a generic Axialkolbenmotor the most effective possible compression, if this is characterized in that the cooperating with a valve drive closure member opens against a limiting system and the valve train is free in the opening direction. This allows on the one hand a targeted closing of the closure part, if this is advantageous and on the other hand, an opening of the closure part, if sufficient pressure prevails in the compressor cylinder.

Cumulatively or alternatively the most effective possible compression in a generic axial piston motor, if this is characterized in that the cooperating with the valve train closure member opens against a limiting system and the valve train acts only against the opening direction of the closure member. This, on the one hand, allows a compulsory closing of the closure part, if this appears advantageous, while the closure part can open, if a sufficient pressure on the combustion medium prevails in the compressor cylinder.

Also in the generic axial piston engine compression and work are separated, so that compression can be carried out at the lowest possible temperatures.

Preferably, the valve train is mechanically formed, which allows a simple and precise control of the closure part.

In a concrete implementation of the valve train may have a pressure system which acts on the closure part, whereby a valve gear which acts only against the opening direction of the closure member, structurally particularly simple can be provided. In a concrete implementation of the valve train can be released in the opening direction, that the pressure application is removed from the closure part.

Thus, the pressure system and the limiting system can be located on a common control module, so that displaced by shifting the control module, the pressure system or the limiting system in a corresponding position and in this way the corresponding compressor outlet valve can be controlled.

Preferably, the pressure system and the limiting system on the control module are integrally formed with each other, which requires a structurally particularly simple design.

In particular, the control assembly may be displaceable between a load position and a release position, wherein in the load position preferably the pressure system and in the unloading position, preferably the limiting system are each positioned so that they can interact with the closure part. In this way, it can be ensured that in the loading position the pressure application device acts on the closure part in a corresponding pressing manner, while in the relief position, only the limiting system limits the valve travel in the opening direction. A corresponding shift can for example take place in that the control module is subjected to a corresponding sliding movement. Likewise, for example, a tilting or rotational movement, for example, a rocker arm or the like may be provided, through which the control module between the loading position and the unloading position changes and each offers the pressure system or the limiting system the closure part for interaction.

Possibly. The pressure system and the limiting system can also be designed identically, which can be realized in particular for example in Andruckstempeln, anchors or rocker arms.

Preferably, the pressure system, the limiting system and / or the control module are sprung. As a result, the forces acting on the closure member can be minimized, so that its life is increased, which is particularly advantageous if the closure part in lightweight construction, for example, made of very light materials or hollow inside. In particular, with regard to the pressure application system, this also ensures a safe closing of the valve, regardless of unavoidable manufacturing tolerances. Alternatively or cumulatively thereto, the closure part may also have a suspension, which is effective for the pressure system, the limiting system or the control module, in order to ensure a corresponding discharge in this way. Also, if necessary, a suspension can serve as a tolerance compensation if the pressure system presses on the same even when the valve is closed and rests against this.

Cumulatively or alternatively to a suspension, the pressure system can be spaced from the closure part with the compressor outlet valve closed, in order to allow a tolerance compensation in this way. This is possible in particular if it is ensured in another way that the compressor outlet valve is reliably closed, which can be ensured, for example, by the inherent mass of the compressor outlet valve and / or the pressure difference via the compressor outlet valve or with other measures, such as by means of magnetic forces , The above-mentioned suspension can then still be used for material-relieving purposes.

The combustion chamber can, as is well known from the prior art, be effective in two stages and a preburner, which essentially serves to thermally treat the main part of the fuel, before this in a main combustion chamber with the combustion medium, which is usually air represents, is brought into contact. It is understood that differently configured combustion chambers can be readily used in corresponding axial piston engines.

As already indicated above, the Brennmediumzuleitung can also be constructed relatively complex. Thus, it is conceivable that the Brennmediumzuleitung has a plurality of parallel lines, which then for example, extend separately from individual compressor cylinders to the combustion chamber. Likewise, the Brennmediumzuleitung also, As already indicated above, comprise further compressor stages and thus first open into another compressor cylinder, and then to lead from the compressor outlet valve or compressor outlet valves to the combustion chamber. Also, after the compressor cylinders, pressure chambers may be provided as constituents of the combustion medium supply line, in which the combustion medium provided by the compressor cylinders is first collected and then fed into one or more supply lines to the combustion chamber. The combustion medium supply line may also comprise one or more heat exchangers with which the combustion medium is heated prior to entry into the combustion chamber, wherein the exhaust gas from the working cylinders or its thermal energy is preferably used here, as already known from the prior art.

Preferably, the one of the Kompressaulaulassventile a poppet valve whose valve cover is the closure member and acts on the Ventilschafft the valve gear. In this way, a corresponding axial piston motor structurally simple and accurate implement. On the other hand, it goes without saying that a ball of a ball valve or also a corresponding hemisphere can optionally be used as the closure part, as long as a corresponding valve drive is also provided here.

The valve drive may in particular have a cam disk or camshaft that is synchronized with an output of the axial piston motor. As a result, a corresponding synchronization structurally simple and precise realize, in which case it is particularly possible to drive the closure member mechanically or via a mechanically designed valve train. On the other hand, it is understood that on the cam or camshaft, an electrical, hydraulic or pneumatic signal can be generated, which can then be used in accordance with the synchronization of the valve train.

Preferably, the valve train also drives further compressor outlet valves or compressor inlet valves, which requires a correspondingly effective design or a very low structural complexity.

As Axialkolbenmotor the directions of movement of the pistons in the compressor and working cylinders are aligned parallel to the output shaft and the output. Preferably, the combustion chamber is arranged centrally to the working cylinders, so that to each of the working cylinder an identical or very similar distance is covered and the axial piston motor works very uniformly.

It is understood that the features of the solutions described above or in the claims can optionally also be combined in order to implement the advantages in a cumulative manner.

Figur 1

einen schematischen Schnitt durch einen Verdichterzylinderkopf eines Axialkolbenmotors bei geschlossenem Verdichterauslassventil;

Figur 2

die Anordnung nach Figur 1 bei geöffnetem Verdichterauslassventil;

Figur 3

einen schematischen Querschnitt durch einen Axialkolbenmotor bei welchem der Verdichterzylinderkopf nach Figuren 1 und 2 zur Anwendung kommen kann;

Figur 4

einen schematischen Schnitt durch die Brennkammer und die Arbeitszylinder des Axialkolbenmotors nach Figur 3;

Figur 5

eine schematische Detaildarstellung eines weiteren Verdichterzylinderkopfs, der bei der Anordnung nach Figuren 3 und 4 zur Anwendung kommen kann, bei geschlossenem Verdichterauslassventil;

Figur 6

die Anordnung nach Figur 5 bei geöffnetem Verdichterauslassventil;

Figur 7

einen weiteren Verdichterzylinderkof, der bei dem Axialkolbenmotor nach Figuren 3 und 4 zur Anwendung kommen kann, im schematischen Schnitt; und

Figur 8

einen weiteren Verdichterzylinderkopf, der bei dem Axialkolbenmotor nach Figuren 3 und 4 zur Anwendung kommen kann, im schematischen Schnitt.

Further advantages, objects and features of the present invention will be explained with reference to the following description of exemplary embodiments, which are shown in particular in the appended drawing. In the drawing show:

FIG. 1

a schematic section through a compressor cylinder head of an axial piston motor with the compressor discharge valve closed;

FIG. 2

the arrangement after FIG. 1 with the compressor outlet valve open;

FIG. 3

a schematic cross section through an axial piston in which the compressor cylinder head after Figures 1 and 2 can be used;

FIG. 4

a schematic section through the combustion chamber and the working cylinder of the axial piston motor after FIG. 3 ;

FIG. 5

a schematic detail of another compressor cylinder head, which in the arrangement according to FIGS. 3 and 4 can be used when the compressor outlet valve is closed;

FIG. 6

the arrangement after FIG. 5 with the compressor outlet valve open;

FIG. 7

another compressor cylinder kof, which in the axial piston motor to FIGS. 3 and 4 can be used, in schematic section; and

FIG. 8

another compressor cylinder head, which in the axial piston motor to FIGS. 3 and 4 can be used, in schematic section.

The in the Figures 1 and 2 shown compressor cylinder head 17 may be in the in FIGS. 3 and 4 shown axial piston motor 10 are used and has at least one Brennmediumeinlass 46 and a Brennmediumauslass 47 to compressor cylinders 40.

The compressed in the compressor cylinders 40 by reciprocating compressor piston 45 compressed combustion medium is collected in a manifold 48, in which the Brennmediumauslässe 47 of the individual compressor cylinder 40 open.

From the collecting tube 48 reaches a multi-part Brennmediumzuleitung 56, which is formed in this embodiment in three parts corresponding to a number of heat exchangers 55, through the heat exchanger 55 to a combustion chamber 20, wherein the manifold 48 is to count the Brennmediumzuleitung 56. In deviant Embodiments, the Brennmediumzuleitung 56 may be simpler or more complex and, for example, still lead to other compressor stages or be interrupted by other compressor stages, which may also have these appropriate valves and Brennmediumeinlässe and / or -auslässe.

Starting from the combustion chamber 20, shot connections 25 each extend to working cylinders 30 which are represented by firing channels 26 which can be opened and closed periodically between the combustion chamber 20 and the respective working cylinders 30. Depending on the concrete implementation of the embodiment, this can be realized for example by rotating around the working cylinder Burt McCullumn slide, by control piston or by coaxial with the combustion chamber 20 arranged rotary rotary valve or the like.

In the working cylinders 30 working piston 35 reciprocate, each connected via a connecting rod 51, each with a compressor piston 45, wherein the connecting rods 51 interact with a cam 52 of an output 50, which is arranged on an output shaft 53. The connecting rod 51 interacts with the cam 52 of the output 50 via a connecting rod bearing 57 (see FIG. 7 ).

The compressor cylinder 40, compressor piston 45, working cylinder 30, working piston 35 and connecting rod 51 are arranged in a star shape coaxially around the combustion chamber 20 and the output shaft 53.

The axial piston motor 10 comprises a housing 16, which has a working cylinder head 15 with the shot channels 26 and lines for exhaust gas 36 and not shown in detail but well known exhaust valves to one side.

Likewise, the housing 16 carries the compressor cylinder head 17th

The exhaust gas 36 is passed into the heat exchanger 55 and its thermal energy is fed into the heat exchanger 55 to the located in the Brennmediumzuleitung 56, compressed combustion medium before it is used in the combustion chamber 20, which operates continuously, for burning fuel. Although in the schematic representation of FIGS. 3 and 4 merely indicated a single-stage combustion chamber. It is understood that here also a multi-stage combustion, in particular with a preburner for the preparation of the fuel, can be provided.

The Brennmediumauslass 47 provided in the compressor cylinder head 17 can be opened and closed by means of a compressor outlet valve 42.

The compressor outlet valve 42 designed as a poppet valve 80 comprises as valve 70 a closure part 71, which is formed by a valve cover 81 of the poppet valve 80, and an opposite 75, which is formed by the compressor cylinder head 17 itself and represents the valve seat 83 of the poppet valve 80. The poppet valve 80 further includes a valve stem 82 which is guided by a valve guide 89 so that the valve 70 can be safely opened and closed. In this case, the valve guide 89 is seated in the compressor cylinder head 17th

As a valve train 60 is a control assembly 65 which is mounted on a sleeve-like control assembly guide 88 in the compressor cylinder head 17 radially displaceable relative to the output shaft 53 and is pressed by a pressure spring 87 against a cam 61, wherein the control assembly 65 carries a cam follower ball 85 which to reduce friction losses on the cam 61 runs. The pressure spring 87 is supported, on the one hand, on the control assembly guide 88 and, on the other hand, on a sleeve 84 in which the control assembly 65 is fastened, so that the control assembly 65 is actuated via the cam disk 61 synchronously with the rotation of the output shaft 53, since the cam disk 61 acts on the Output shaft 53 is placed.

Between the valve stem 82 and the control assembly 65, a control ball 86 is provided to reduce friction losses.

The control assembly 65 has a limiting device 73 and a pressure system 74, which are provided at different positions of the control assembly 65 seen radially with respect to the output shaft 53. Depending on the curved path of the cam disk 61, the limiting system 73 or the pressing system 74 can then be brought into an interaction position with the control ball 86 by the cam disk 61.

Viewed in the axial direction, the pressing system 74 is provided so close to the valve seat 83 that the valve cover 81 is pressed against the valve seat 83 and the compressor outlet valve 42 is closed when the pressing system 74 is disposed in its interaction position with respect to the control ball 86, as this in FIG. 1 is shown.

If, however, the limiting system 73 is arranged in its interaction position with respect to the control ball 86, the valve cover 81 can open from its valve seat 83 in an opening direction 72 when the gas pressure in the compressor cylinder 40 exceeds the gas pressure in the Brennmediumauslass 47, as this in FIG. 2 is shown as an example.

In that regard, the control assembly 65 and the valve train 60 releases the valve 70 in the opening direction 72 when the limiting system 73 is arranged in its interaction position with the control ball 86. The valve can then open itself controlled by the gas pressure. If, on the other hand, the pressure drive 74 of the control assembly 65 is brought into the interaction position with the control ball 86 by the valve drive 60, the valve 70 is forcibly closed.

The limiting device 73 and the pressure device 74 are provided on a resilient arm of the control assembly 65, so that the control assembly 65 resiliently interacts with the closure member 71 of the valve 70. This relieves on the one hand the material of the valve 70 and on the other hand serves to ensure the closing of the valve 70 a secure fit of the closure member 71 on its opposite 75, especially taking into account unavoidable manufacturing tolerances.

In this embodiment, the geometries between the pressure device 74 and the valve stem 82, the control ball 86 and the valve seat 83 are coordinated such that the pressure device 74, when brought in its position of interaction to the control ball 86, with closed compressor outlet valve 42 of the Control ball 86 remains spaced so as to take into account any tolerances in this way. The compressor outlet valve 42 closes ballistically, ie by its own movement and mass, when it has been accelerated by the control assembly 65 in the closing direction accordingly. Incidentally, the pressure difference across the compressor outlet valve 42 also acts valve-closing, and the top dead center of the corresponding compressor piston 45 has been reached. It is understood that in an alternative embodiment, if necessary, the pressure system 74 may rest against the control ball 86 in its interaction position, even when the compressor outlet valve 42 is closed, when the suspension is sufficiently matched to the tolerances.

At the in FIGS. 5 and 6 illustrated embodiment, a magnet 90 is used with an armature 91 as a valve drive 60, which also interact with a designed as a poppet valve 80 valve 70.

The valve guide 89 is embedded in an aluminum support 93, which on the side of the armature 91, which faces away from the magnet 90, carries a stop 94, against which springs 92 press the armature 91. If the magnet 90 is acted upon by a current, then the armature 91 is against the spring force of the springs 92 and against the opening direction 72 pulled against the magnet 90. If the magnet 90 is turned off, the springs 92 can push the armature 91 in the opening direction 72 against the stop 94 again.

In the area of the aluminum carrier 93, the region of the compressor cylinder head 17 surrounding the aluminum carrier 93 has cooling ribs 95.

This arrangement also makes it possible for the closure part 71 of the valve 70 to open freely in the opening direction and only conditionally due to the gas pressure difference between the compressor cylinder 40 and the fuel medium vent 47, while it can be closed via the magnet 90. In this case, the shaft of the armature 91 which comes into contact with the closure part 71 of the valve 70 serves both as a limiting device 73 and as a pressure system 74, whereby the compressor outlet valve 42 or the valve 70 is forcibly closed by tightening the armature 91 against the opening direction 72 of the valve 70 can be.

In this embodiment, the valve stem 81 and the valve seat 83 and the shaft of the armature 91 are matched in their geometries with one another such that the contact pressure system 74 rests against the valve stem 81 even when the compressor outlet valve 42 is closed. Here, a small gap between the armature 91 and magnet 90 can remain for tolerance compensation. Alternatively, a ballistic closing of the compressor outlet valve 42 can also be provided here by the valve shaft 81 or the shaft of the armature 91 being correspondingly shorter, so that the pressure system 74 does not bear against the valve stem 81 when the compressor outlet valve 42 is closed.

The in the FIGS. 7 and 8 arrangements shown show possible embodiments of compressor inlet valves 41, which are also controlled by the cam disk 61, which acts there as a camshaft 62, however. In this case, the respective compressor inlet valve 41 is actuated via an actuating lever 99. LIST OF REFERENCE NUMBERS 10 axial piston motor 60 valve train 15 Cylinder head 61 cam 16 casing 62 camshaft 17 Compressor cylinder head 65 control module 20 combustion chamber 70 Valve 25 Shot connection (numbered as an example) 71 closing part 72 opening direction 26 Shot channel (numbered as an example) 73 limiting investment 74 Andruckanlage 30 Working cylinder (numbered as an example) 75 opposite 35 working piston 80 poppet valve 36 exhaust 81 valve cover 82 valve stem 40 compression cylinder 83 valve seat 41 Compressor inlet valve 84 shell 42 Verdichterauslassventil 85 Cam follower ball 45 pistons compressor 86 trackball 46 Burning medium inlet 87 pressure spring 47 Brennmediumauslass 88 Control assembly guide 48 manifold 89 valve guide 50 output 90 magnet 51 pleuel 91 anchor 52 cam 92 feather 53 output shaft 93 aluminum support 55 heat exchangers 94 attack 56 Burning media inlet 95 cooling fins 57 connecting rod bearing 99 actuating lever

Claims (18)

1. A method for operating an axial piston motor (10), in which fuel and compressed combustion medium are continuously burnt in a combustion chamber (20) to form working medium and successively fed to working cylinders (30) in which working pistons (35) run back and forth which in turn drive an output (50) and compressor pistons (45) which run back and forth in compressor cylinders (40) in which the combustion medium is compressed, the combustion medium being drawn in via compressor inlet valves (41), and the compressed combustion medium being fed to the combustion chamber (20) by the compressor cylinders (40) via compressor outlet valves (42), characterised in that at least one of the compressor outlet valves (42) is closed in a positively controlled manner and is opened by means of a compressor pressure building up in the respective compressor cylinder (40).
2. The operating method according to claim 1, characterised in that the closing process of the at least one of the compressor outlet valves (42) is initiated before the associated compressor piston (45) reaches top dead centre.
3. The operating method according to claim 2, characterised in that the closing process of the at least one of the compressor outlet valves (42) is initiated at the latest 5°, preferably at the latest 7°, before the associated compressor piston (45) reaches top dead centre.
4. The operating method according to any one of claims 1 to 3, characterised in that the at least one of the compressor outlet valves (42) is closed when the associated compressor piston (45) reaches top dead centre.
5. The operating method according to any one of claims 1 to 4, characterised in that the at least one of the compressor outlet valves (42) is closed freely by its own weight after initiation of the closing process.
6. The operating method according to any one of claims 1 to 5, characterised in that the at least one of the compressor outlet valves (42) is released before the compression process.
7. The operating method according to any one of claims 1 to 6, characterised in that the at least one of the compressor outlet valves (42) is driven mechanically.
8. The operating method according to any one of claims 1 to 7, characterised in that the at least one of the compressor outlet valves (42) is driven synchronously with an output (50) of the axial piston motor (10).
9. An axial piston motor (10) having: a combustion chamber (20), which continuously burns compressed combustion medium and fuel to form working medium; working cylinders (30), which are connected to the combustion chamber (20) by means of cyclically openable and closable firing connections (25) and in which working pistons (35) run back and forth; compressor cylinders (40), in which compressor pistons (45) run back and forth, which are driven by the working pistons (35); and at least one combustion medium feed line (56), which leads from compressor outlet valves (42) of the compressor cylinders (40) to the combustion chamber (20), at least one of the compressor outlet valves (42) having a closure part (71) which opens away from the compressor cylinder (40), characterised in that the closure part (71), which interacts with a valve drive (60), opens against a limiting structure (73), and the valve drive (60) can be released in the opening direction (72) and/or acts on the closure part (71) only counter to the opening direction (72).
10. The axial piston motor (10) according to claim 9, characterised in that the valve drive (60) is mechanical.
11. The axial piston motor (10) according to claim 9 or 10, characterised in that the valve drive (60) has a pressure application structure (74) which acts on the closure part (71).
12. The axial piston motor (10) according to claim 11, characterised in that the pressure application structure (74) is spaced from the closure part (71) of the compressor outlet valve (42) when the latter is closed.
13. The axial piston motor (10) according to claim 11 or 12, characterised in that the pressure application structure (74) and the limiting structure (73) are situated on a control assembly (65) and are preferably formed integrally with each other.
14. The axial piston motor (10) according to claim 13, characterised in that the control assembly (65) can be displaced between a loading position and a non-loading position.
15. The axial piston motor (10) according to any one of claims 9 to 14, characterised in that the pressure application structure, the limiting structure and/or the control assembly are spring-loaded.
16. The axial piston motor (10) according to any one of claims 9 to 15, characterised in that one of the compressor outlet valves (42) is a poppet valve (80), the valve cover (81) of which is the closure part (71) and on the valve stem (82) of which the valve drive (60) acts.
17. The axial piston motor (10) according to any one of claims 9 to 16, characterised in that the valve drive (60) has a cam disc (61) or a camshaft (62), which are synchronised with an output (50) of the axial piston motor (10).
18. The axial piston motor (10) according to any one of claims 9 to 17, characterised in that the valve drive (60) also drives further compressor outlet valves (42) and/or compressor inlet valves (41).

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