Method for operating an axial piston motor, and axial piston motor

Abstract

In an axial piston motor in which fuel and compressed combustion medium are continuously burned in a combustion chamber so as to be turned into the working fluid and successively be delivered to working cylinders, at least one of the compressor discharge valves is closed in a positively controlled manner and is opened by a compressor pressure building up in the respective compressor cylinder.

Claims

1. A method for operation of an axial piston motor comprising: continuously combusting fuel and compressed combustion medium in a combustion chamber to produce working medium; delivering the working medium to successive working cylinders; drawing the combustion medium into compressor cylinders by way of compressor inlet valves; moving working pistons back and forth in the working cylinders to drive a power take-off and compressor pistons back and forth in the compressor cylinders to produce the compressed combustion medium; delivering the compressed combustion medium to the combustion chamber by the compressor cylinders by way of compressor outlet valves; closing at least one of the compressor outlet valves with positive control via a valve drive producing a closing force affecting a closure part of the at least one of the compressor outlet valves; and opening the at least one of the compressor outlet valves by way of a removal of the closing force of the valve drive and by way of a compressor pressure that builds up in the respective compressor cylinder.

2. The operating method according to claim 1, wherein the closing process of the at least one of the compressor outlet valves is initiated before the related compressor piston reaches its top dead center.

3. The operating method according to claim 2, wherein the closing process of the at least one of the compressor outlet valves is initiated no later than 7 before the related compressor piston reaches its top dead center.

4. The operating method according to claim 2, wherein the closing process of the at least one of the compressor outlet valves is initiated no later than 5 before the related compressor piston reaches its top dead center.

5. The operating method according to claim 1, wherein the at least one of the compressor outlet valves is closed when the related compressor piston reaches its top dead center.

6. The operating method according to claim 1, wherein the at least one of the compressor outlet valves is freely closed by its own weight after the closing process has been initiated.

7. The operating method according to claim 1, wherein the positive control is released from the at least one of the compressor outlet valves before the compression process.

8. The operating method according to claim 1, wherein the at least one of the compressor outlet valves is mechanically driven.

9. The operating method according to claim 1, wherein the at least one of the compressor outlet valves is driven synchronously to a power take off of the axial piston motor.

10. An axial piston motor having a combustion chamber that combusts continuously compressed combustion medium and fuel to produce working medium, having working cylinders that are connected with the combustion chamber by connections that can open and close cyclically, having working pistons moving back and forth in the working cylinders, having compressor cylinders in which compressor pistons move back and forth, which compressor pistons are driven by the working pistons, having at least one combustion medium feed line that leads from compressor outlet valves of the compressor cylinders to the combustion chamber, and having a valve drive configured to exert a positive control acting on a closure part of at least one of the compressor outlet valves in an opening direction, the closure part opening away from the compressor cylinder, wherein the closure part interacts with the valve drive and opens counter to a restriction arrangement, and wherein the valve drive releases the closure part in the opening direction so that a compressor pressure that builds up in the compressor cylinder is able to open the at least one of the compressor outlet valves and/or exerts the positive control acting on the closure part only in the opening direction.

11. The axial piston motor according to claim 10, wherein the valve drive is configured mechanically.

12. The axial piston motor according to claim 10, wherein the valve drive has a press-down arrangement that acts on the closure part.

13. The axial piston motor according to claim 12, wherein the press-down arrangement and the restriction arrangement are configured in one piece with one another.

14. The axial piston motor according to claim 12, wherein the press-down arrangement is at a distance from the closure part when the compressor outlet valve is closed.

15. The axial piston motor according to claim 12, wherein the press-down arrangement and the restriction arrangement are situated on a control module.

16. The axial piston motor according to claim 15, wherein the control module can be displaced between a stress position and a relief position.

17. The axial piston motor according to claim 10, wherein the press-down arrangement, the restriction arrangement and/or the control module are mounted resiliently.

18. The axial piston motor according to claim 10, wherein the one of the compressor outlet valves is a plate valve, the valve cover of which is the closure part and on the valve shaft of which the valve drive acts.

19. The axial piston motor according to claim 10, wherein the valve drive has a cam disk or a cam shaft, which is synchronized with a power take-off of the axial piston motor.

20. The axial piston motor according to claim 10, wherein the valve drive also drives further compressor outlet valves and/or compressor inlet valves.

Description

(1) Further advantages, goals, and properties of the present invention will be explained using the following description of exemplary embodiments, which are also shown, in particular, in the attached drawing. The drawing shows:

(2) FIG. 1 a schematic section through a compressor cylinder head of an axial piston motor, with the compressor outlet valve closed;

(3) FIG. 2 the configuration according to FIG. 1, with the compressor outlet valve open;

(4) FIG. 3 a schematic cross-section through an axial piston motor, in which the compressor cylinder head according to FIGS. 1 and 2 can be used;

(5) FIG. 4 a schematic section through the combustion chamber and the working cylinders of the axial piston motor according to FIG. 3;

(6) FIG. 5 a schematic detail representation of a further compressor cylinder head, which can be used in the configuration according to FIGS. 3 and 4, with the compressor outlet valve closed;

(7) FIG. 6 the configuration according to FIG. 5, with the compressor outlet valve open;

(8) FIG. 7 a further compressor cylinder head, which can be used in the axial piston motor according to FIGS. 3 and 4, in schematic section; and

(9) FIG. 8 a further compressor cylinder head, which can be used in the axial piston motor according to FIGS. 3 and 4, in schematic section.

(10) The compressor cylinder head 17 shown in FIGS. 1 and 2 can be used in the axial piston motor 10 shown in FIGS. 3 and 4, and has at least one combustion medium inlet 46 and one combustion medium outlet 47 to compressor cylinders 40.

(11) The combustion medium, which is compressed in the compressor cylinders 40 by means of compressor pistons 45 that move back and forth is collected in a manifold 48, into which the combustion medium outlets 47 of the individual compressor cylinders 40 open.

(12) A multi-part combustion medium feed line 56, which is configured in three parts in this exemplary embodiment, in accordance with the number of heat exchangers 55, reaches from the manifold 48 through the heat exchangers 55 to a combustion chamber 20, wherein the manifold 48 should also be counted as part of the combustion medium feed line 56. In deviating embodiments, the combustion medium feed lie 56 can be structured in simpler or more complex manner, and can also lead to further compressor stages, for example, or can be interrupted by further compressor stages, wherein these can also have corresponding valves and combustion medium inlets and/or outlets, if applicable.

(13) Proceeding from the combustion chamber 20, shot connections 25 extend to working cylinders 30, in each instance, which are represented by shot channels 26 between the combustion chamber 20 and the respective working cylinders 30, which can be periodically opened and closed. Depending on the concrete implementation of the exemplary embodiment, this can be implemented, for example, by means of Burt-McCollum sleeve valves that surround the working cylinders, by means of control pistons or by means of rotary valves disposed coaxially relative to the combustion chamber 20 or the like.

(14) Working pistons 35 move back and forth in the working cylinders 30; these pistons are connected with a compressor piston 45, in each instance, by way of a piston rod 51, wherein the piston rods 51 interact with a cam disk 52 of a power take-off 50, which disk is disposed on a power take-off shaft 53. The piston rod 51 interacts with the cam disk 52 of the power take-off 50 by way of a large end bearing 57 (see FIG. 7).

(15) The compressor cylinders 40, compressor pistons 45, working cylinders 30, working pistons 35, and piston rods 51 are disposed coaxially around the combustion chamber 20 and the power take-off shaft 53, in star shape.

(16) The axial piston motor 10 comprises a housing 16, which has a working cylinder head 15 having the shot channels 26 as well as lines for exhaust gas 36 and exhaust gas valves, which are not shown in any detail but are sufficiently known, on one side.

(17) Likewise, the housing 16 carries the compressor cylinder head 17.

(18) The exhaust gas 36 is conducted into the heat exchangers 55 and its thermal energy is conducted, in the heat exchangers 55, to the compressed combustion medium that is situated in the combustion medium feed line 56, before this medium is used for combustion of fuel in the combustion chamber 20, which works continuously. It is true that in the schematic representation of FIGS. 3 and 4, only a single-stage combustion chamber is indicated. It is understood that here, multi-stage combustion, in particular with a pre-burner for preparation of the fuel, can also be provided.

(19) The combustion medium outlet 47 provided in the compressor cylinder head 17 can be opened and closed by means of a compressor outlet valve 42.

(20) The compressor outlet valve 42 configured as a plate valve 80 comprises a closure part 71 as a valve 70, which part is formed by a valve cover 81 of the plate valve 80, as well as a counter-part 75, which is formed by the compressor cylinder head 17 itself and represents the valve seat 83 of the plate valve 80. The plate valve 80 furthermore comprises a valve shaft 82, which is guided by a valve guide 89, so that the valve 70 can be reliably opened and closed. In this regard, the valve guide 89 sits in the compressor cylinder head 17.

(21) A control module 65, which is mounted in the compressor cylinder head 17 so as to be radially displaceable with reference to the power take-off shaft 53, by way of a sleeve-like control module guide 88, and is pressed against a cam disk 61 by way of a press-down spring 87, serves as a valve drive 60, wherein the control module 65 carries a cam follower ball 85 that runs on the cam disk 61 in order to reduce friction losses. The press-down spring 87 supports itself on the control module guide 88, on the one side, and on a sleeve 84, on the other side, in which the control module 65 is attached, so that the control module 65 is controlled synchronously to the rotation of the power take-off shaft 53 by way of the cam disk 61, since the cam disk 61 is set onto the power take-off shaft 53.

(22) A control ball 86 is provided between the valve shaft 82 and the control module 65, so as to reduce friction losses.

(23) The control module 65 has a restriction arrangement 73 and a press-down arrangement 74, which are provided at different positions of the control module 65, viewed radially with reference to the power take-off shaft 53. Thendepending on the cam track of the cam disk 61the restriction arrangement 73 or the press-down arrangement 74 can be brought into an interaction position with the control ball 86 by means of the cam disk 61.

(24) Viewed in the axial direction, the press-down arrangement 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 press-down arrangement 74 is disposed in its interaction position with reference to the control ball 86, as shown in FIG. 1.

(25) If, in contrast, the restriction arrangement 73 is disposed in its interaction position with reference to the control ball 86, then the valve cover 81 can open from its valve seat 83 in an opening direction 72, if the gas pressure in the compressor cylinder 40 exceeds the gas pressure in the combustion medium outlet 47, as shown as a example in FIG. 2.

(26) To this extent, the control module 65, i.e. the valve drive 60 releases the valve 70 in the opening direction 72 if the restriction arrangement 73 is disposed in its interaction position relative to the control ball 86. The valve can then open on its own, controlled by the gas pressure. If, on the other hand, the press-down arrangement 74 of the control module 65 is brought into the interaction position with the control ball 86 by the valve drive 60, then the valve 70 is compulsorily closed.

(27) The restriction arrangement 73 as well as the press-down arrangement 74 are provided on a resilient arm of the control module 65, so that the control module 65 resiliently interacts with the closure part 71 of the valve 70. This relieves stress on the material of the valve 70, on the one hand, and on the other hand serves to guarantee a reliable seat of the closure part 71 on its counter-part 75, in particular also taking unavoidable production tolerances into consideration.

(28) In this exemplary embodiment, the geometries between the press-down arrangement 74 and the valve shaft 82, the control ball 86 or the valve seat 83 are coordinated with one another in such a manner that the press-down arrangement 74 remains at a distance from the control ball 86 when it is brought into its interaction position relative to the control ball 86, when the compressor outlet valve 42 is closed, so as to take possible production tolerances into consideration in this manner. The compressor outlet valve 42 in itself closes ballistically, in other words due to its own movement and mass, if it was accelerated in the closing direction accordingly by the control module 65. Furthermore, the pressure difference above the compressor outlet valve 42 also acts to close the valve as soon as the top dead center of the corresponding compressor piston 45 has been reached. It is understood that in an alternative embodiment, the press-down arrangement 74 can possibly lie against the control ball 86 in its interaction position, even when the compressor outlet valve 42 is closed, if the resilient mounting is sufficiently coordinated with the tolerances.

(29) In the case of the exemplary embodiment shown in FIGS. 5 and 6, a magnet 90 having an armature 91 serves as the valve drive 60; these also interact with a valve 70 structured as a plate valve 80.

(30) The valve guide 89 is recessed into an aluminum support 93, which carries a stop 94 on the side of the armature 91 that faces away from the magnet 90, against which stop springs 92 press the armature 91. When current is applied to the magnet 90, the armature 91 is pulled against the magnet 90 counter to the spring force of the springs 92 and counter to the opening direction 72. When the magnet 90 is turned off, the springs 92 are able to press the armature 91 against the stop 94 again, in the opening direction 72.

(31) In the region of the aluminum support 93, the region of the compressor cylinder head 17 that surrounds the aluminum support 93 has cooling ribs 95.

(32) This configuration also makes it possible that the closure part 71 of the valve 70 can open freely in the opening direction and in limited manner only due to the pressure difference between compressor cylinder 40 and combustion medium outlet 47, whereas it can be closed by way of the magnet 90. In this regard, the shaft of the armature 91 that comes into contact with the closure part 71 of the valve 70 serves both as a restriction arrangement 73 and as a press-down arrangement 74, wherein the compressor outlet valve 42, i.e. the valve 70 can be compulsorily closed counter to the opening direction 72 of the valve 70, by means of attraction of the armature 91.

(33) In this exemplary embodiment, the valve shaft 81 or the valve seat 83 and the shaft of the armature 91 are coordinated with one another in terms of their geometries, in such a manner that the press-down arrangement 74 lies against the valve shaft 81 even when the compressor outlet valve 42 is closed. Here, a small gap can remain between armature 91 and magnet 90 for tolerance equalization. Alternatively, ballistic closing of the compressor outlet valve 42 can also be provided here, in that the valve shaft 81 or the shaft of the armature 91 are configured to be correspondingly shorter, so that the press-down arrangement 74 does not lie against the valve shaft 81 when the compressor outlet valve 42 is closed.

(34) The configurations shown in FIGS. 7 and 8 show possible embodiments of compressor inlet valves 41, which are also controlled by way of the cam disk 61, which, however, acts as a cam shaft 62 there. In this regard, the respective compressor inlet valve 41 is controlled by way of an actuation lever 99.

REFERENCE SYMBOL LIST

(35) 10 axial piston motor 15 working cylinder head 16 housing 17 compressor cylinder head 20 combustion chamber 25 shot connection (numbered as an example) 26 shot channel (numbered as an example) 30 working cylinder (numbered as an example) 35 working piston 36 exhaust gas 40 compressor cylinder 41 compressor inlet valve 42 compressor outlet valve 45 compressor piston 46 combustion medium inlet 47 combustion medium outlet 48 manifold 50 power take-off 51 piston rod 52 cam disk 53 power take-off shaft 55 heat exchanger 56 combustion medium feed line 57 large end bearing 60 valve drive 61 cam disk 62 cam shaft 65 control module 70 valve 71 closure part 72 opening direction 73 restriction arrangement 74 press-down arrangement 75 counter-part 80 plate valve 81 valve cover 82 valve shaft 83 valve seat 84 sleeve 85 cam follower ball 86 control ball 87 press-down spring 88 control module guide 89 valve guide 90 magnet 91 armature 92 spring 93 aluminum support 94 stop 95 cooling ribs 99 actuation lever