CYLINDER/RECIPROCATING-PISTON DEVICE, COMPRESSED AIR ENGINE, AND VEHICLE

Abstract

A cylinder/reciprocating-piston device for a compressed air engine includes a hollow cylinder having a hollow-cylinder wall defining a pressure space, a piston that is movable the pressure space, and valves that respectively open/close valve flow channels in the hollow-cylinder wall. The hollow-cylinder has a surface that delimits the pressure space in a radial direction, a ceiling wall that axially upwardly delimits the pressure space, a floor wall that axially downwardly delimits the pressure space, and a piston-rod opening in the floor- and/or ceiling wall that slidably guide(s) a piston rod. The piston divides the pressure space into a first pressure chamber between the piston and the ceiling wall, and a second pressure chamber between the piston and the floor wall. A minimum flow-cross section of one or more of the valve flow channels is preferably at least 10% of the effective cross-sectional surface area of the piston.

Claims

1. A cylinder/reciprocating-piston device for a compressed air engine, the cylinder/reciprocating-piston device including: a hollow cylinder, which is closed upwardly and downwardly, having a hollow-cylinder wall, a piston, and a plurality of valves each having a valve closure part configured to close off a valve flow channel extending through the valve, the valves being selected from the group consisting of electric valves, pneumatically-actuated valves, hydraulically-actuated valves and mechanically-actuated valves, wherein: the hollow-cylinder wall defines a pressure space and comprises: a surface that delimits the pressure space in a radial direction, a ceiling wall that upwardly delimits the pressure space in an axial direction, a floor wall that downwardly delimits the pressure space in the axial direction, and a piston-rod opening in at least one of the floor wall and the ceiling wall, the piston-rod opening(s) being configured such that a piston rod attached to the piston is guidable therethrough from outside into the pressure space, the piston is disposed in the pressure space such that the piston divides the pressure space into a first pressure chamber between the piston and the ceiling wall, and a second pressure chamber between the piston and the floor wall, the piston is displaceable in the pressure space in a pressure-tight manner in the axial direction by a piston stroke that is defined between a first end position, at which the piston is located in the vicinity of or in abutment with the ceiling wall, and a second end position, at which the piston is located in the vicinity of or in abutment with the floor wall, the hollow-cylinder wall further includes: at least one first-pressure-chamber opening, via which a first pressure medium is supplyable into and/or dischargeable from the first pressure chamber through the valve flow channel of at least a first one of the plurality of valves, and at least one second-pressure-chamber opening, via which a second pressure medium is supplyable into and/or dischargeable from the second pressure chamber through the valve flow channel of at least a second one of the plurality of valves, the first pressure chamber has a first displacement that is calculated by multiplying the piston stroke with a first effective cross-sectional surface area of a first side of the piston that faces the first pressure chamber, the second pressure chamber has a second displacement that is calculated by multiplying the piston stroke with a second effective cross-sectional surface area of a second side of the piston that faces the second pressure chamber, and the piston, the valves and the pressure space are configured such that: when the piston is located at the first end position, a first dead space volume is the sum of a first volume within the first pressure chamber defined between the ceiling wall and the piston at the first end position, if any, and a second volume defined by a space within the valve flow channel(s) of the at least first one of the plurality of valves between the first pressure chamber and the valve closure part(s) thereof disposed in a closed state, the first dead space volume being less than 15% of the first displacement, and when the piston is located at the second end position, a second dead space volume is the sum of a third volume within the second pressure chamber defined between the floor wall and the piston at the second end position, if any, and a fourth volume defined by a space within the valve flow channel(s) of the at least second one of the plurality of valves between the second pressure chamber and the valve closure part(s) thereof disposed in a closed state, the second dead space volume being less than 15% of the second displacement.

2.-4. (canceled)

5. A cylinder/reciprocating-piston device for a compressed air engine, the cylinder/reciprocating-piston device including: a hollow cylinder, which is closed upwardly and downwardly, having a hollow-cylinder wall, a piston, and a plurality of valves each having a valve closure part configured to close a valve flow channel extending through the valve, the valves being selected from the group consisting of electric valves, pneumatically-actuated valves, hydraulically-actuated valves and mechanically-actuated valves, wherein: the hollow-cylinder wall defines a pressure space and comprises: a surface that delimits the pressure space in a radial direction, a ceiling wall that upwardly delimits the pressure space in an axial direction, a floor wall that downwardly delimits the pressure space in the axial direction, and a piston-rod opening in at least one of the floor wall and the ceiling wall, the piston-rod opening(s) being configured such that a piston rod attached to the piston is guidable therethrough from outside into the pressure space, the piston is disposed in the pressure space such that the piston divides the pressure space into a first pressure chamber between the piston and the ceiling wall, and a second pressure chamber between the piston and the floor wall, the piston is displaceable in the pressure space in a pressure-tight manner in the axial direction by a piston stroke that is defined between a first end position, at which the piston is located in the vicinity of or in abutment with the ceiling wall, and a second end position, at which the piston is located in the vicinity of or in abutment with the floor wall, the hollow-cylinder wall further includes: one or more inlet first-pressure-chamber openings, via which a first pressure medium is supplyable through the valve flow channel of at least a first one of the plurality of valves into the first pressure chamber, and one or more outlet first-pressure-chamber openings, via which the first pressure medium is dischargeable through the valve flow channel of at least a second one of the plurality of valves out of the first pressure chamber, and/or one or more inlet second-pressure-chamber openings, via which a second pressure medium is supplyable through the valve flow channel of at least a third one of the plurality of valves into the second pressure chamber, and one or more outlet second-pressure-chamber openings, via which the second pressure medium is dischargeable through the valve flow channel of at least a fourth one of the plurality of valves out of the second pressure chamber, each of the valve flow channels of the plurality of valves has a minimum flow-cross-section in an open state of the valve closure part, the minimum flow-cross-section of the first one of the plurality of valves, or the sum of the minimum flow-cross-sections of a plurality of the first one of the plurality of valves, is/are more than 10% of an effective cross-sectional surface area of the piston, and/or the minimum flow-cross-section of the second one of the plurality of valves, or the sum of the minimum flow-cross-sections of a plurality of the second one of the plurality of valves, is/are more than 10% of the effective cross-sectional surface area of the piston, and/or the minimum flow-cross-section of the third one of the plurality of valves, or the sum of the minimum flow-cross-sections of a plurality of the third one of the plurality of valves, is/are more than 10% of the effective cross-sectional surface area of the piston, and/or the minimum flow-cross-section of the fourth one of the plurality of valves, or the sum of the minimum flow-cross-sections of a plurality of the fourth one of the plurality of valves, is/are more than 10% of the effective cross-sectional surface area of the piston.

6.-9. (canceled)

10. A compressed air engine comprising: at least two cylinder/reciprocating-piston devices (1), each having a hollow cylinder, which is closed upwardly and downwardly, having a hollow-cylinder wall with at least one piston-rod opening, a piston movably disposed in the hollow cylinder, and a plurality of valves each having a valve closure part configured to close a valve flow channel extending through the valve, the valves being selected from the group consisting of electric valves, pneumatically-actuated valves, hydraulically-actuated valves and mechanically-actuated valves, a common piston rod connected with the pistons of the cylinder/reciprocating-piston devices and movably extending outward through the piston-rod openings of the hollow-cylinder walls, and a first crankshaft coupled with the common piston rod such that the back-and-forth movement of the common piston rod is converted into rotational movement of the first crankshaft, wherein: each of the hollow-cylinder walls defines a pressure space and comprises: a surface that delimits the pressure space in a radial direction, a ceiling wall that upwardly delimits the pressure space in an axial direction, a floor wall that downwardly delimits the pressure space in the axial direction, and the at least one piston-rod opening in at least one of the floor wall and the ceiling wall, the piston-rod opening(s) being configured such that the common piston rod is guidable therethrough from outside into the pressure space, the pistons are respectively disposed in the pressure spaces such that the pistons respectively divide each of the pressure spaces into a first pressure chamber between the piston and the ceiling wall, and a second pressure chamber between the piston and the floor wall, the pistons are respectively displaceable in the pressure spaces in a pressure-tight manner in the axial direction by a piston stroke that is defined between a first end position, at which the piston is located in the vicinity of or in abutment with the ceiling wall, and a second end position, at which the piston is located in the vicinity of or in abutment with the floor wall, each of the hollow-cylinder walls further includes: at least one first-pressure-chamber opening, via which a first pressure medium is supplyable into and/or dischargeable from the first pressure chamber through the valve flow channel of at least a first one of the plurality of valves, and at least one second-pressure-chamber opening, via which a second pressure medium is supplyable into and/or dischargeable from the second pressure chamber through the valve flow channel of at least a second one of the plurality of valves, the at least two cylinder/reciprocating-piston devices are disposed on the same side relative to a connection of the common piston rod with the first crankshaft, and the first pressure medium is the same as or different from the second pressure medium.

11. The compressed air engine according to claim 10, further including one of: a pressure regulator configured to adjust the pressure of the first and second pressure medium supplied to the first and second pressure chambers via the valves, or a first pressure regulator configured to adjust the pressure of the first pressure medium supplied to the first pressure chamber via the at least first one of the plurality of valves and a second pressure regulator configured to adjust the pressure of the second pressure medium supplied to the second pressure chamber via the at least second one of the plurality of valves.

12. The compressed air engine according to claim 10, further including: a rotational angle sensor configured to detect the rotational position of the first crankshaft to facilitate controlling of the plurality of valves in a manner depending on the detected rotational position of the first crankshaft, and a control system configured to control the plurality of valves such that the cylinder/reciprocating-piston devices are selectively switchable between: a 1-stroke mode, wherein in every movement between the first and second end positions the piston is impinged with pressure medium, and a multi-stroke mode, wherein in some but not all movements between the first and second end positions the piston is not impinged with pressure medium, wherein the valves are selected from the group consisting of electric valves, pneumatically-actuated valves, and hydraulically-actuated valves.

13. The compressed air engine according to claim 10, wherein: the control system is further configured to change the rotational direction of the first crankshaft and/or the at least two of the cylinder/reciprocating-piston devices are differently designed.

14.-15. (canceled)

16. The compressed air engine according to claim 10, further comprising: first piston rod and a second piston rod, each of which is connected to the first crankshaft and to one of the at least two cylinder/reciprocating-piston devices.

17. The compressed air engine according to claim 10, wherein: the at least two cylinder/reciprocating-piston devices, and/or crank arms of the first crankshaft, which connect the crankshaft to the common piston rod, are configured differently such that the at least two cylinder/reciprocating-piston devices have different displacements and/or different stroke heights.

18. The compressed air engine according to claim 10, wherein: the pressure of the first and/or second pressure medium of each of the first and second pressure chambers of the at least two of the cylinder/reciprocating-piston devices is adjustable independently of one another, and/or the first pressure media of the at least two of the cylinder/reciprocating-piston devices are, at least in part, different from each other, and/or the second pressure media of the at least two of the cylinder/reciprocating-piston devices are, at least in part, different from each other.

19. (canceled)

20. The compressed air engine according to claim 10, wherein: the valves are selected from the group consisting of electric valves, pneumatically-actuated valves, and hydraulically-actuated valves, and a control system is configured to control the plurality of valves of at least two cylinder/reciprocating-piston devices such that at least two of the cylinder/reciprocating-piston devices operate with different stroke times and/or with different pressure differences between the first and second pressure chamber in the first and second end positions, and/or are switchable-off independently of one another, and/or the control system is configured to determine control times of the plurality of valves in a manner that is dependent on a load situation.

21. (canceled)

22. The compressed air engine according to claim 10, wherein the first crankshaft is connected with the common piston rod via a connecting rod such that the common piston rod is linearly guided.

23. The compressed air engine according to claim 10, further including: a second crankshaft configured to operate as a dual crank drive together with the first crankshaft, wherein: the first crankshaft and the second crankshaft are configured to rotate in opposite directions at the same rotational speed, and the common piston rod is connected with the first and second crankshafts (75) via a connecting rod such that the common piston rod is linearly guided, and during rotation of the dual crank drive about a 360-degree crank angle, the pistons are configured to be respectively moved from the first end position to the second end position, and back again to the first end position.

24. A vehicle comprising: at least one compressed air engine according to claim 10, at least one pressure tank configured to store at least the first pressure medium and fluidly connected with the at least one first-pressure-chamber openings of the at least two cylinder/reciprocating-piston devices.

25.-30. (canceled)

31. The compressed air engine according to claim 10, wherein, in at least one of the at least two cylinder/reciprocating-piston devices: the first pressure chamber has a first displacement that is calculated by multiplying the piston stroke with a first effective cross-sectional surface area of a first side of the piston that faces the first pressure chamber, the second pressure chamber has a second displacement that is calculated by multiplying the piston stroke with a second effective cross-sectional surface area of a second side of the piston that faces the second pressure chamber, and the piston, the valves and the pressure space are configured such that: when the piston is located at the first end position, a first dead space volume is the sum of a first volume within the first pressure chamber defined between the ceiling wall and the piston at the first end position, if any, and a second volume defined by a space within the valve flow channel(s) of the at least first one of the plurality of valves between the ceiling wall and the valve closure part(s) thereof disposed in a closed state, the first dead space volume being less than 15% of the first displacement, and when the piston is located at the second end position, a second dead space volume is the sum of a third volume within the second pressure chamber defined between the floor wall and the piston at the second end position, if any, and a fourth volume defined by a space within the valve flow channel(s) of the at least second one of the plurality of valves between the floor wall and the valve closure part(s) thereof disposed in a closed state, the second dead space volume being less than 15% of the second displacement.

32. The compressed air engine according to claim 10, wherein, in at least one of the at least two cylinder/reciprocating-piston devices: the at least one first-pressure-chamber opening extends through the ceiling wall, and the at least one second-pressure-chamber opening extends through the floor wall.

33. The compressed air engine according to claim 10, wherein, in at least one of the at least two cylinder/reciprocating-piston devices: the at least one first-pressure-chamber opening includes one or more inlet first-pressure-chamber openings, via which the first pressure medium is supplyable through the valve flow channel of at least the first one of the plurality of valves into the first pressure chamber, and one or more outlet first-pressure-chamber openings, via which the first pressure medium is dischargeable through the valve flow channel of at least a third one of the plurality of valves out of the first pressure chamber, and/or the at least second first-pressure-chamber opening includes one or more inlet second-pressure-chamber openings, via which the second pressure medium is supplyable through the valve flow channel of at least the second one of the plurality of valves into the second pressure chamber, and one or more outlet second-pressure-chamber openings, via which the second pressure medium is dischargeable through the valve flow channel of at least a fourth one of the plurality of valves out of the second pressure chamber.

34. The compressed air engine according to claim 10, wherein, in at least one of the at least two cylinder/reciprocating-piston devices: each of the valve flow channels of the plurality of valves has a minimum flow-cross-section in an open state of the valve closure part, the minimum flow-cross-section of the first one of the plurality of valves, or the sum of the minimum flow-cross-sections of a plurality of the first one of the plurality of valves, is/are more than 10% of an effective cross-sectional surface area of the piston, and/or the minimum flow-cross-section of the second one of the plurality of valves, or the sum of the minimum flow-cross-sections of a plurality of the second one of the plurality of valves, is/are more than 10% of the effective cross-sectional surface area of the piston, and/or the minimum flow-cross-section of the third one of the plurality of valves, or the sum of the minimum flow-cross-sections of a plurality of the third one of the plurality of valves, is/are more than 10% of the effective cross-sectional surface area of the piston, and/or the minimum flow-cross-section of the fourth one of the plurality of valves, or the sum of the minimum flow-cross-sections of a plurality of the fourth one of the plurality of valves, is/are more than 10% of the effective cross-sectional surface area of the piston.

35. The compressed air engine according to claim 34, wherein: the minimum flow-cross-section of the first one of the plurality of valves, or the sum of the minimum flow-cross-sections of a plurality of the first one of the plurality of valves, is/are more than 20% of an effective cross-sectional surface area of the piston, and/or the minimum flow-cross-section of the second one of the plurality of valves, or the sum of the minimum flow-cross-sections of a plurality of the second one of the plurality of valves, is/are more than 20% of the effective cross-sectional surface area of the piston, and/or the minimum flow-cross-section of the third one of the plurality of valves, or the sum of the minimum flow-cross-sections of a plurality of the third one of the plurality of valves, is/are more than 20% of the effective cross-sectional surface area of the piston, and/or the minimum flow-cross-section of the fourth one of the plurality of valves, or the sum of the minimum flow-cross-sections of a plurality of the fourth one of the plurality of valves, is/are more than 20% of the effective cross-sectional surface area of the piston

36. The compressed air engine according to claim 10, wherein at least one of the at least two cylinder/reciprocating-piston devices has a first piston-rod opening in the floor wall and a second piston-rod opening in the ceiling wall.

37. The compressed air engine according to claim 31, wherein: the first dead space volume is less than 5% of the first displacement, and the second dead space volume is less than 5% of the second displacement.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0115] Exemplary embodiments of the invention are explained in the following based on the Figures.

[0116] FIG. 1 shows a schematic construction of a cylinder/reciprocating-piston device according to a first embodiment with a piston located in the central position.

[0117] FIG. 2 shows region A denoted in FIG. 1 in enlarged schematic representation.

[0118] FIG. 3 shows a schematic construction of a cylinder/reciprocating-piston device according to a further embodiment with a piston located in a first end position, electric valves in a closed position, and a piston rod connected with the piston, for the illustration of the first dead space volume and the second dead space volume.

[0119] FIG. 4 shows a schematic construction of a compressed air engine according to a first embodiment, in which the piston is located in (at) the second end position.

[0120] FIG. 5 shows the compressed air engine shown in FIG. 4, in which the piston is located in (at) the first end position.

[0121] FIG. 6A-6C shows various exemplary embodiments of different compressed air engines in schematic representations.

[0122] FIG. 7 shows a vehicle according to a first embodiment in schematic representation.

DETAILED DESCRIPTION

[0123] FIG. 1 shows a cylinder/reciprocating-piston device according to a first embodiment with a piston located in the central position. The cylinder/reciprocating-piston device 1 includes a hollow cylinder 5 having rotational axis R. The hollow cylinder 5 is closed off upward and downward. Therefore, a hollow-cylinder inner wall 10 of the hollow cylinder 5 forms a pressure space 20. A surface 25 delimits the pressure space 20 in the radial direction. A ceiling wall 30 delimits the pressure space 20 upward in the axial direction. A floor wall 40 delimits the pressure space 20 downward in the axial direction. In FIG. 1, the piston 15 is located approximately centrally between the ceiling wall 30 and the floor wall 40. The piston 15 divides the pressure space 20 into a first pressure chamber 55 that lies between the piston 15 and the ceiling wall 30, and a second pressure chamber 60, that lies between the piston 15 and the floor wall 40. The piston 15 is movably disposed in the pressure space 20. Thus, the volume of the first pressure chamber and the volume of the second pressure chamber each change depending on the position of the piston 15.

[0124] Two first-pressure-chamber openings 35 are located in the ceiling wall 30 of the hollow cylinder 5. The leftmost of the two first-pressure-chamber openings 35 shown is an inlet first-pressure-chamber opening 36, via which a pressure (pressurized) medium is supplyable into the first pressure chamber 55. The rightmost of the two first-pressure-chamber openings 35 shown is an outlet first-pressure-chamber opening 37, via which the pressure medium is dischargeable or ejectable out of the first pressure chamber 55.

[0125] Two second-pressure-chamber openings 45 are located in the floor wall 40 of the hollow cylinder 5. The leftmost of the two second-pressure-chamber openings 45 shown is an inlet second-pressure-chamber opening 46, via which a pressure (pressurized) medium is supplyable into the second pressure chamber 60. The rightmost of the two second-pressure-chamber openings 45 shown is an outlet second-pressure-chamber opening 47, via which the pressure medium is dischargeable or ejectable out of the second pressure chamber 60.

[0126] Furthermore, a piston-rod opening 50 is located in the floor wall 40. A piston rod can be guided from outside into the pressure space 20 through the piston-rod opening 50. An electric valve 65 is located in each of the inlet first-pressure-chamber opening 36, the outlet first-pressure-chamber opening 37, the outlet second-pressure-chamber opening 46, and the outlet second-pressure-chamber opening 47. The electric valves 65 are each illustrated in a simplified manner.

[0127] FIG. 2 shows region A, which is denoted in FIG. 1, in enlarged schematic representation. The inlet first-pressure-chamber opening 36 and the outlet first-pressure-chamber opening 37 are located in the ceiling wall 30 of the hollow cylinder 5.

[0128] The electric valve 65, which is inserted (disposed) in the inlet first-pressure-chamber opening 36, is schematically shown. The electric valve 65 is inserted into (disposed in) the inlet first-pressure-chamber opening 36 in a fluid-tight manner. The electric valve 65 comprises a valve flow channel 66 that is closable with the aid of a valve closure part 67. The valve closure part 67 of the inlet first-pressure-chamber opening 36 is located in (rotated to) the open position in FIG. 2. In the open position of the valve closure part 67, the flow channel 66 has a minimum flow-cross-section 68. The depiction of the valve 65, and in particular of the valve closure part 67, is to be understood to be a schematic representation that serves for the elucidation of the relevant features of the electric valve 65.

[0129] The electric valve 65, which is inserted (disposed) in the outlet first-pressure-chamber opening 37, is also schematically shown. The electric valve 65 is also inserted into (disposed in) the outlet first-pressure-chamber opening 37 in a fluid-tight manner. This electric valve 65 also comprises a valve flow channel 66 that is closable with the aid of a valve closure part 67. The valve closure part 67 of the outlet first-pressure-chamber opening 36 is located in (rotated to) the closed position in FIG. 2. The flow channel 66 of the outlet first-pressure-chamber opening 36 is thus blocked.

[0130] FIG. 3 shows a cylinder/reciprocating-piston device 1 according to a further embodiment with a piston 15 located in (at) the first end position, electric valves in the closed position, and a piston rod 70, connected with the piston 15, for the depiction of the first dead space volume and of the second dead space volume.

[0131] The state shown in FIG. 3 can correspond, for example, to the state in which the vehicle is stationary. The electric valves 67 are all located in (rotated to) the closed position. The piston 15 is located in (rotated to) first end position OT. The piston 15 is also depicted, in dashed line, in (at) the second end position UT. The piston moves with the stroke (distance) H between the first end position OT and the second end position UT. The piston 15 has the piston outer diameter D.sub.K.

[0132] The volume fillable with pressure (pressurized) medium, which volume is located between the valve closure part 67, located in the closed position, of the inlet first-pressure-chamber opening 36, and the valve closure part 67, located in (rotated to) the closed position, of the outlet first-pressure-chamber opening 37, and the piston 15, is the first dead space volume 56.

[0133] The first dead space volume 56 is thus composed on the one hand of the volume of the first pressure chamber 55, which is formed when the piston 15 is located in (rotated to) the first end position OT, and on the other hand from the volume fillable with pressure medium, which volume is located between the valve closure part 67, located in (rotated to) the closed position, of the inlet first-pressure-chamber opening 36, and the valve closure part 67, located in (rotated to) the closed position, of the outlet first-pressure-chamber opening 37, and the first pressure chamber 55. The first dead space volume 56 is shown in FIG. 3 in dotted representation above the piston 15.

[0134] The volume fillable with pressure medium, which volume is located between the valve closure part 67, located in (rotated to) the closed position, of the inlet second-pressure-chamber opening 46, and the valve closure part 67, located in (rotated to) the closed position, of the outlet second-pressure-chamber opening 47, and the piston 15, is the second dead space volume 57.

[0135] The second dead space volume 57 is thus composed on the one hand of the volume of the second pressure chamber 60 that forms when the piston 15 is located in (at) the second end position UT, and on the other hand from the volume, fillable with pressure medium, that is located between the valve closure part 67, located in (rotated to) the closed position, of the inlet second-pressure-chamber opening 46, and the valve closure part, located in (rotated to) the closed position 67 of the outlet second-pressure-chamber opening 47, and the second pressure chamber 60. The second dead space volume 57 is shown in FIG. 3 in dotted representation below the piston 15.

[0136] FIG. 4 shows a compressed air engine 100 according to a first embodiment, in which the piston 15 is located in (at) the second end position UT. The compressed air engine 100 comprises one cylinder/reciprocating-piston device 1. A piston rod 70 is connected with the piston 15 of the cylinder/reciprocating-piston device 1. The piston rod 70 is connected with two crankshafts 75 by one connecting rod 71 each. The crank drive shown in FIG. 4 is a so-called dual-crank drive. The piston rod 70 extends through the piston-rod opening 50 of the cylinder/reciprocating-piston device 1. The piston-rod opening 50 is sealed with respect to the piston rod 70 by seals 79.

[0137] The flow direction of the pressure (pressurized) medium into the first pressure chamber, as well as out of the second pressure chamber, is indicated in FIG. 4 with straight arrows. The state shown in FIG. 4 corresponds to a state in which pressure medium is supplied through the supply first-pressure-chamber opening 36 into the first pressure chamber 55, and simultaneously pressure medium is discharged from the second pressure chamber 60 out of the outlet second-pressure-chamber opening 47. In a simplified manner not to scale, a pressure tank 105 and a pressure regulator 110 are also shown in FIG. 4. The pressure regulator 110 is fluidly connected between the pressure tank 105 and the cylinder/reciprocating-piston device 1 (connection lines for pressure medium indicated with dotted lines).

[0138] The state shown in FIG. 4 corresponds to an exemplary control state of the electric valves, in which the electric valves are switched precisely in (at) the first end position or in the second end position of the piston 15. The control times thus correspond to a crankshaft-angle position of 0/180/360.

[0139] The outlet first-pressure-chamber opening 37 as well as the supply second-pressure-chamber opening 46 are each closed off by an electric valve (65) with a valve closure part (67) located in (rotated to) the closed position as shown by curved arrows. Due to such a flow of the pressure medium in the first pressure chamber 55 and in the second pressure chamber 60, respectively, the piston moves to its second end position UT. Thus, the piston 15 shown in FIG. 4 has precisely reached (is precisely disposed at) its second end position UT. In this state the switching of the valves follows from off to on, or from on to off.

[0140] FIG. 5 shows the compressed air engine 100 of FIG. 4 in a state in which the piston 15 is located in (at) a first end position OT. In FIG. 5, the flow direction of the pressure medium into the first pressure chamber 55 and out of the second pressure chamber 60 is indicated with straight arrows. The state shown in FIG. 5 corresponds to a state in which pressure medium is supplied through the supply second-pressure-chamber opening 46 into the first pressure chamber 55, and simultaneously pressure medium is discharged from the second pressure chamber 60 out of the outlet first-pressure-chamber opening 37. In a simplified manner not to scale, the pressure tank 105 and the pressure regulator 110 are again shown in FIG. 5. The same as FIG. 4, the pressure regulator 110 is fluidly connected between the pressure tank 105 and the cylinder/reciprocating-piston device 1 (connection lines for pressure medium indicated with dotted lines).

[0141] The supply first-pressure-chamber opening 36 and the outlet second-pressure-chamber opening 47 are each closed off by an electric valve (65) with a valve closure part (67) located in (rotated to) the closed position as shown in FIG. 5 by curved arrows.

[0142] Due to such a flow of the pressure medium in the first pressure chamber 55 and in the second pressure chamber 60, respectively, the piston 15 moves to its first end position OT. The piston shown in FIG. 5 is already located in (at) the first end position OT.

[0143] FIG. 6A-6C shows various embodiments of compressed air engines according to the present disclosure in schematic view.

[0144] FIG. 6A shows a compressed air engine having two cylinder/reciprocating-piston devices 1. The two cylinder/reciprocating-piston devices 1 are connected with two crankshafts 75 via a common piston rod 70. The two cylinder/reciprocating-piston devices 1 are located on opposing sides of the crankshafts 75. The two cylinder/reciprocating-piston devices 1 are of the same size. In a simplified manner, a control system 115 and a rotational angle sensor 120 are also shown in FIG. 6A. The control system 115 is shown as being configured to control, i.e., to open and to close, the electric valves of the upper cylinder/reciprocating-piston device 1 (control communication illustrated in dotted lines). A signal from the rotational angle sensor 120, which determines the rotational position of the crankshaft(s) 75 and transmits this value to the control system 115, serves as input value for the control system 115 (transmission connection illustrated in dotted lines). The electric valves of the lower cylinder/reciprocating-piston device 1 may also be controlled by the control system 115 in the same manner.

[0145] FIG. 6B shows a (another) compressed air engine having three cylinder/reciprocating-piston devices 1. The three cylinder/reciprocating-piston devices 1 are connected with two crankshafts 75 via a common piston rod 70. Two cylinder/reciprocating-piston devices 1 are located above the crankshafts 75, and one cylinder/reciprocating-piston device 1 is located below the crankshafts 75. The three cylinder/reciprocating-piston devices 1 are differently sized, but have the same stroke.

[0146] FIG. 6C shows a (another) compressed air engine having ten cylinder/reciprocating-piston devices 1. The compressed air engine of FIG. 6C includes two adjacently disposed crankshafts 75 (corresponding to the embodiments in FIG. 6A and FIG. 6B), similar to the designs shown in FIGS. 4 and 5, but only one of which crankshafts 75 is shown in FIG. 6C.

[0147] Four of the in total ten cylinder/reciprocating-piston devices 1 are connected with the crankshafts 75 via a common first piston rod 70. A further four of the ten cylinder/reciprocating-piston devices 1 are connected with the crankshafts 75 via a common second piston rod 70. A further two of the ten cylinder/reciprocating-piston devices 1 are connected with the crankshafts 75 via a common third piston rod 70. The two cylinder/reciprocating-piston devices 1 that are connected with the third piston rod 70 have a greater stroke height than the other cylinder/reciprocating-piston devices. Greater stroke heights enable the crank arms of the crank arms of the crankshaft, to which crank arms the respective piston rod is connected, to be made longer, and thus the connection between piston rod and crank arm can be radially farther removed (spaced) from the rotational axis of the crankshaft than with a short crank arm. With a half rotation of the crankshaft, the longer coupling arm correspondingly results in a larger stroke of the piston rod. In this way, different strokes of cylinder/reciprocating-piston devices can be realized with one crankshaft and different coupling arms.

[0148] FIG. 7 shows a vehicle according to a first embodiment in schematic representation. More specifically, FIG. 7 shows a vehicle 150 with four drive wheels 106, each of the four drive wheels 106 is (individually) driven by a single compressed air engine 100. The corresponding four compressed air engines 100 are attached (fluidly connected) to a (common) pressure tank 105. The pressure tank 105 extends in the longitudinal direction centrally in the vehicle 150.

[0149] It is explicitly emphasized that all features disclosed in the description and/or the claims are to be seen as separate and independent from one another for the purpose of the original disclosure, as well as independent of the feature combinations in the embodiments and/or in the claims for the purpose of the limiting of the claimed invention. It is explicitly held that all range specifications, or specifications of groups of units disclose every possible intermediate value or subgroup of units for the purpose of the original disclosure, as well as for the purpose of the limiting of the claimed invention, in particular also as limit of a range specification.

REFERENCE NUMBER LIST

[0150] 1 Cylinder/reciprocating-piston device [0151] 5 Hollow cylinder [0152] 10 Hollow-cylinder inner wall [0153] 15 Piston [0154] 20 Pressure space [0155] 25 Surface [0156] 30 Ceiling wall [0157] 35 First-pressure-chamber opening [0158] 36 Inlet first-pressure-chamber opening [0159] 37 Outlet first-pressure-chamber opening [0160] 40 Floor wall [0161] 45 Second-pressure-chamber opening [0162] 46 Inlet second-pressure-chamber opening [0163] 47 Outlet second-pressure-chamber opening [0164] 50 Piston-rod opening [0165] 51 Pressure sensor [0166] 52 Temperature sensor [0167] 55 First pressure chamber [0168] 56 First dead space volume [0169] 57 Second dead space volume [0170] 60 Second pressure chamber [0171] 65 Electric valve [0172] 66 Valve flow channel [0173] 67 Valve closure part [0174] 68 Minimum flow-cross-section [0175] 70 Piston rod [0176] 75 Crankshaft [0177] 100 Compressed air engine [0178] 105 Pressure tank [0179] 106 Drive wheel [0180] 110 Pressure regulator [0181] 115 Control system [0182] 120 Rotational angle sensor [0183] OT First end position [0184] UT Second end position [0185] H Piston stroke [0186] D.sub.K Piston outer diameter