Axial piston engine and method for operating an axial piston engine

Abstract

To improve the efficiency of an axial piston engine, the invention proposes an axial piston engine with a combustion chamber which operates with two-stage combustion.

Claims

1. An axial piston engine with continuous combustion which operates with two-stage combustion comprises: a combustion chamber; a main fuel nozzle; a preparation fuel nozzle; wherein the combustion chamber comprises a main combustion chamber and a preparation chamber, wherein a portion of combustion air is introduced into the preparation chamber and the preparation fuel nozzle injects a corresponding quantity of preparation fuel into the preparation chamber, wherein the preparation chamber is arranged upstream of the main combustion chamber, wherein main fuel is added into the preparation chamber by the main fuel nozzle, which main fuel is heated in the preparation chamber, wherein exhaust gas or a preparation fuel/air mixture is introduced into the preparation chamber from the preparation fuel nozzle, wherein the main fuel injected into the preparation chamber from the main fuel nozzle is injected without an air supply ensuring that a preparation process of the main fuel is carried out in said preparation chamber without combustion, and wherein a quantity of air which corresponds to a quantity of main fuel introduced into the main combustion chamber through the main fuel nozzle is introduced into the main combustion chamber downstream of the preparation chamber; at least two working cylinders; at least one firing channel provided per each working cylinder; and a control piston for closing and opening the at least one firing channel to control combustion products flowing out of the main combustion chamber to the at least two working cylinders.

2. Axial piston engine according to claim 1, wherein the portion of combustion air is less than 50% of the total combustion air.

3. Axial piston engine according to claim 1, wherein the main fuel nozzle is aligned parallel to a main combustion direction in the combustion chamber.

4. Axial piston engine according to claim 3, wherein the main fuel nozzle is aligned coaxially to an axis of symmetry of the combustion chamber which lies parallel to the main combustion direction in the combustion chamber.

5. Axial piston engine according to claim 1, wherein the preparation fuel nozzle is aligned at an angle to the main fuel nozzle.

6. Axial piston engine according to claim 5, wherein a jet direction of the preparation fuel nozzle intersects a jet direction of the main fuel nozzle.

7. Axial piston engine according to claim 1, wherein both the main fuel nozzle and the preparation fuel nozzle are oriented into the preparation chamber and wherein the preparation chamber opens towards the main combustion chamber.

8. Axial piston engine according to claim 1, wherein the preparation fuel nozzle opens into the preparation chamber, via which the main fuel is heated in the preparation chamber.

9. Axial piston engine according to claim 7, wherein the preparation chamber is aligned parallel to a main combustion direction in the combustion chamber.

10. Axial piston engine according to claim 9, wherein the preparation chamber is aligned coaxially to an axis of symmetry of the combustion chamber which lies parallel to the main combustion direction in the combustion chamber.

11. Axial piston engine according to claim 7, wherein the preparation chamber has a smaller diameter than the main combustion chamber.

12. Axial piston engine according to claim 7, wherein the preparation chamber comprises a prechamber and a main chamber.

13. Axial piston engine according to claim 12, wherein a jet direction of the preparation fuel nozzle and a jet direction of the main fuel nozzle intersect in the prechamber.

14. Axial piston engine according to claim 12, wherein the prechamber widens towards the main chamber.

15. Axial piston engine according to claim 1, further comprising a separate air supply to the combustion chamber.

16. Axial piston engine according to claim 1, wherein one of the main fuel nozzle and the preparation fuel nozzle has a perforated rim for an air supply.

17. Axial piston engine with continuous combustion according to claim 1, wherein a piston cover of the control piston has a greater diameter than the firing channel.

18. Axial piston engine according to claim 1, wherein the control piston executes an essentially radially oriented stroke movement.

19. Axial piston engine according to claim 1, wherein the control piston executes an essentially axially oriented stroke movement.

20. Axial piston engine according to claim 1, wherein the control piston is water-cooled.

21. Axial piston engine according to claim 1, wherein the control piston is actuated desmodromically.

22. Axial piston engine according to claim 1, wherein the control piston is actuated over a curved path.

23. Axial piston engine according to claim 1, wherein the control piston is secured against rotation.

24. Axial piston engine according to claim 1, wherein the control piston bears a control piston ring.

25. Axial piston engine according to claim 24, wherein the control piston ring has a slot.

26. Axial piston engine according to claim 24, wherein the control piston ring is secured against rotation.

Description

(1) In the drawing,

(2) FIG. 1 schematically shows an axial piston engine in longitudinal section;

(3) FIG. 2 schematically shows the axial piston engine according to FIG. 1 in cross section along line H-H;

(4) FIG. 3 schematically shows an enlarged illustration of the firing channel ring of FIG. 1;

(5) FIG. 4 schematically shows a longitudinal section through a control piston as an alternative to the control piston according to FIGS. 1 and 2; and

(6) FIG. 5 schematically shows a cross section through the control piston according to FIG. 4 along the line V-V.

(7) The axial piston engine 1 shown in FIG. 1 has a combustion chamber 2 in which a fuel/air mixture can be ignited and burned. The axial piston engine 1 advantageously operates with two-stage combustion. To this end, the combustion chamber 2 has a first region 3 and a second region 4 into which the fuel and/or air can be injected. In particular in the first region in 3, a portion of combustion air of the axial piston engine 1 can be introduced, wherein in this exemplary embodiment the portion of combustion air can be set to be less than 15% of the total combustion air.

(8) The combustion chamber 2 of the axial piston engine 1 can be divided by the two regions 3 and 4 into a preparation chamber 5 and a main combustion chamber 6.

(9) The preparation chamber 5 has a smaller diameter than the main combustion chamber 6, wherein the preparation chamber 5 is further divided into a prechamber 7 and a main chamber 8. The prechamber 7 has a conical configuration and widens towards the main chamber 8.

(10) There is connected to the preparation chamber 5, in particular to the prechamber 7 of the preparation chamber 5, a main nozzle 9 on one side and a preparation nozzle 10 on the other side. A fuel can be introduced into the combustion chamber 2 by means of the main nozzle 9 and the preparation nozzle 10, wherein the fuel which is injected by means of the preparation nozzle 10 is already mixed with air.

(11) The main nozzle 9 is aligned parallel to a main combustion direction 11 in the combustion chamber 2 of the axial piston engine 1. Furthermore, the main nozzle 9 is aligned coaxially to an axis of symmetry 12 of the combustion chamber 2 which lies parallel to the main combustion direction 11 in the combustion chamber 2.

(12) The preparation nozzle 10 is aligned at an angle 13 to the main nozzle 9. In this respect, a jet direction 14 of the preparation nozzle 10 intersects a jet direction 15 of the main nozzle 9 at an intersection point 16.

(13) The preparation chamber 5, into which both the main nozzle 9 and the preparation nozzle 10 are oriented, opens towards the main combustion chamber 6. Fuel is injected out of the main nozzle 9 into the preparation chamber 5 without additional supply of air. The fuel is already preheated, ideally thermally decomposed, in the preparation chamber 5.

(14) To this end, the quantity of air which corresponds to the quantity of fuel which flows through the main nozzle 9 is introduced into the main combustion chamber 6 downstream of a preparation chamber 5, for which a separate air supply 17 is provided which opens essentially into the main combustion chamber 6. To this end, the separate air supply 17 is connected to a process air supply 18, wherein a further air supply 19 can be supplied with air, which supplies a perforated rim 20 with air. The perforated rim 20 is allocated to the preparation nozzle 10 so that the fuel which is injected with the preparation nozzle 10 can additionally be injected into the prechamber 7 of the preparation chamber 5 with process air.

(15) The combustion chamber 2, in particular the main combustion chamber 6 of the combustion chamber 2, has a ceramic assembly 21 which is air-cooled. The ceramic assembly 21 in this case comprises a ceramic combustion chamber wall 22 which is surrounded by a profiled tube 23. A cooling air chamber 24 extends around this profiled tube 23, which cooling air chamber is operatively connected to the process air supply 18 by means of a cooling air chamber supply 25.

(16) Furthermore, the axial piston engine 1 has working cylinders 30 which are known per se (see in particular FIG. 2), in which working pistons 31 can be moved forwards and backwards.

(17) Compressor pistons 32 of the axial piston engine 1 are driven by means of the working pistons 31, which compressor pistons can be moved correspondingly in suitable compressor cylinders 33 of the axial piston engine 1. The working pistons 31 are connected to the compressor pistons 32 in each case by means of a connection rod 34, wherein a connection rod wheel 35 is arranged in each case between the working piston 31 and the connection rod 34 and between the compressor piston 32 and the connection rod 34. A drive curved path 36 is enclosed in each case between two connection rod wheels 35, which drive curved path is guided on a drive curved path support 37. Opposite the combustion chamber 2, the axial piston engine 1 has a drive shaft 38, by means of which the power generated by the axial piston engine 1 can be output. The process air is compressed in the compressor pistons 32 in a manner which is known per se, including where applicable the injected water, which may lead to additional cooling, as a result of which however the exhaust gases can if applicable be cooled much more in a heat exchanger if the process air is to be guided to the combustion chamber 2 preheated by means of such a heat exchanger, wherein the process air can be heated or preheated by contact with other assemblies of the axial piston engine 1 which must be cooled, as described above. The process air which has been compressed and heated in this manner is then added to the combustion chamber 2 in a manner which has already been explained.

(18) Each of the working cylinders 30 is connected to the combustion chamber 2 of the axial piston engine 1 by means of a firing channel 39, so that the fuel/air mixture can pass out of the combustion chamber 2 via the firing channel 39 and into the working cylinder 30, and can drive the working piston 31 there.

(19) In this respect the working medium flowing out of the combustion chamber 2 can be supplied successively to at least two working cylinders 30 via at least one firing channel 39, wherein one firing channel 39 is provided per working cylinder 30, which firing channel can be closed and opened by means of a control piston 40. The number of the control pistons 40 of the axial piston engine 1 is thus also predefined by the number of the working cylinders 30.

(20) The firing channel 39 in this case is closed essentially by means of the control piston 40 with its piston cover 41. The control piston 40 is driven by means of a control piston curved path 42, wherein a spacer 43 for the control piston curved path 42 to the drive shaft 38 is provided, which is also used in particular for thermal decoupling. In the present exemplary embodiment, the control piston 40 can execute an essentially axially oriented stroke movement 44. To this end, each control piston 40 is guided by means of sliding blocks (not numbered) which are mounted in the control piston curved path 42, wherein the sliding blocks in each case have a securing cam which runs back and forth in a guide groove (not numbered) and prevents the control piston 40 from rotating.

(21) As the control piston 40 comes into contact with the hot working medium from the combustion chamber 2 in the region of the firing channel 39, it is advantageous if the control piston 40 is water-cooled. To this end, the axial piston engine 1 has a water-cooling system 45, in particular in the region of the control piston 40, wherein the water-cooling system 45 comprises inner cooling channels 46, intermediate cooling channels 47 and outer cooling channels 48. Well-cooled in this manner, the control piston 40 can be moved in an operationally reliable manner in a corresponding control piston cylinder 49.

(22) The firing channels 39 and the control pistons 40 can be provided in the axial piston engine 1 in a particularly simple manner in design terms if the axial piston engine 1 has a firing channel ring 50 as is illustrated in particular in FIG. 3.

(23) The firing channel ring 50 has a centre axis 51, around which in particular the parts of the working cylinders 30 and the control piston cylinders 49 of the axial piston engine 1 are concentrically arranged. A firing channel 39 is provided between each working cylinder 30 and control piston cylinder 49, wherein each firing channel 39 is connected spatially with a recess 52 (see FIG. 3) of a combustion chamber bottom 53 (see FIG. 1) of the combustion chamber 2 of the axial piston engine 1. The working medium can thus pass from the combustion chamber 2 via the firing channels 39 and into the working cylinders 30, and carry out work there, by means of which the compressor cylinders 33 of the axial piston engine 1 can also be moved. It is self-evident that, depending on the actual configuration, coating and inserts can also be provided in order to protect the firing channel ring 50 or its material from direct contact with corrosive combustion products or excessive temperatures.

(24) The alternative control piston 60 which is shown by way of example in FIGS. 4 and 5 has a wheel 61 for the control piston curved path 37 of the axial piston engine 1. The wheel 61 is provided on an end 64 of the control piston 60 which faces away from the piston cover 41 in the same manner as a rotation securing means 63 which is configured as a ball 62. The ball 62 can advantageously also be used as a longitudinal guide of the control piston 60 in the present case. Furthermore, the control piston 60 comprises a piston ring 65, which is situated directly below the piston cover 41. The piston ring 65 is secured on the control piston 60 by means of a piston ring securing means 66. A pressure compensation means 67 for the control piston 60 is also provided between the piston ring 65 and the ball 62.

LIST OF REFERENCE SYMBOLS

(25) 1 Axial piston engine 2 Combustion chamber 3 First region 4 Second region 5 Preparation chamber 6 Main combustion chamber 7 Prechamber 8 Main chamber 9 Main nozzle 10 Preparation nozzle 11 Main combustion direction 12 Axis of symmetry 13 Angle 14 Jet direction of preparation nozzle 15 Jet direction of main nozzle 16 Intersection point 17 Separate air supply 18 Process air supply 19 Further air supply 20 Perforated rim 21 Ceramic assembly 22 Ceramic combustion chamber wall 23 Profiled tube 24 Cooling air chamber 25 Cooling air chamber supply 30 Working cylinder 31 Working piston 32 Compressor piston 33 Compressor cylinder 34 Connection rod 35 Connection rod wheel 36 Drive curved path 37 Drive curved path support 38 Drive shaft 39 Firing channel 40 Control piston 41 Piston cover of control piston 42 Control piston curved path 43 Spacer for control piston curved path 44 Axially oriented stroke movement 45 Water-cooling system 46 Inner cooling channels 47 Intermediate cooling channels 48 Outer cooling channels 49 Control piston cylinder 50 Firing channel ring 51 Centre axis 52 Recess 53 Combustion chamber bottom 60 Alternative control piston 61 Wheel 62 Ball 63 Rotation securing means 64 End facing away 65 Piston ring 66 Piston ring securing means 67 Pressure-compensating means