AIR MOTOR AND VEHICLE

Description

[0001] The present invention relates to a compressed air motor with at least two cylinder-reciprocating piston devices and a vehicle with such a compressed air motor.

[0002] Engines are used to convert energy and use it to power vehicles, for example. Machines that convert heat into mechanical energy are called heat engines. Examples of heat engines include steam engines, steam turbines, and all internal combustion engines. A large proportion of today's internal combustion engines are reciprocating piston engines. Reciprocating piston engines work with a piston that is movably arranged in a cylinder. In this variable cavity, part of the energy is extracted from a gaseous or liquid working medium through combustion. The expansion of the working medium during combustion causes the piston to move. The piston is connected to a crankshaft via joints and a piston rod. The linear movement of the piston is translated into a rotary movement of the crankshaft. The piston moves back and forth between two end positions within the cylinder.The end positions are called first dead center and second dead center. The movement from one end position to the other is called a stroke.

[0003] Conventional reciprocating piston engines are largely 2-stroke and 4-stroke reciprocating piston engines. In a 2-stroke reciprocating piston engine, work is performed on the piston every other stroke by expanding the working fluid. In a 4-stroke reciprocating piston engine, work is performed on the piston every fourth stroke by expanding the working fluid. The stroke in which work is performed on the piston by expanding the working fluid is also called the power or combustion stroke.

[0004] Because 2-stroke and 4-stroke reciprocating piston engines each perform work in a single stroke, these engines typically use multiple cylinders. The crankshafts in these conventional multi-stroke engines are designed so that the power strokes in the respective cylinders are offset from one another. A crankshaft is the unit consisting of the piston, piston rod and / or connecting rod, crankshaft, and the joints between them. A corresponding reciprocating piston engine is known, for example, from DE 198 39 227 A1.

[0005] To overcome the disadvantages of the conventional combustion engine, electric drive systems for vehicles have recently been further developed. However, these systems pose significant environmental problems, including manufacturing and disposal.

[0006] US 9 217 329 B1 describes a drive system and in particular a drive system with compressed air which supplies drive torque to a vehicle transmission and drive torque to an electronic generator for charging a battery.

[0007] US 2021 / 231111 A1 describes a compressed air motor and US 10 280 754 B2 discloses a hydraulic motor and a hydraulic fluid-powered vehicle.

[0008] EP 1 710 394 A1 relates to a machine intended for use in the power generation industry as a motor, pump and compressor.

[0009] Against this background, the present invention is based on the object of specifying components for an improved engine, an improved engine with such components and an improved vehicle with an improved engine.

[0010] This object is achieved by a compressed air motor having the features of independent claim 1 and a vehicle having the features of independent claim 15. Further developments are specified in the dependent claims.

[0011] The core of the invention is to provide components for an efficient and flexibly deployable and operable compressed air motor and such a compressed air motor.

[0012] The cylinder-reciprocating piston device according to this disclosure comprises at least two cylinder-reciprocating piston devices that are dual-acting and can be filled or emptied with a pressure medium via preferably electric valves. In particular, in such a pneumatic motor, several cylinder-reciprocating piston devices can be flexibly interconnected.

[0013] The cylinder-reciprocating piston device according to this disclosure comprises a hollow cylinder in which a piston can move up and down. The hollow cylinder preferably has a cylindrical outer surface. Alternatively, the hollow cylinder can also have other outer surfaces, for example, rectangular or oval. However, the inner surface, through which the pressure chamber of the cylinder-reciprocating piston device is formed, is preferably always cylindrical.

[0014] The hollow cylinder is made of cast iron, aluminum, light metal alloys, or plastics (due to their low operating temperatures). The hollow cylinder can be a single piece or assembled from multiple parts.

[0015] The inner surface of the hollow cylinder and the outer surface of the piston are coordinated or designed in such a way that the piston can be moved within the hollow cylinder in a pressure-tight manner. The inner wall of the hollow cylinder forms a pressure chamber which is divided by the piston into a first pressure chamber and a second pressure chamber, which are separated from each other in a pressure-tight manner. With the movement of the piston, the volume of the first pressure chamber changes in the opposite direction to the volume of the second pressure chamber. The inner wall of the hollow cylinder has at least one first pressure chamber opening and one second pressure chamber opening. One or more pressure media can be supplied to and discharged from the first and second pressure chamber openings via the first and second pressure chamber openings. The piston is made, for example, from aluminum, an aluminum alloy, or plastic.

[0016] The at least one first pressure chamber opening and the at least one second pressure chamber opening are designed such that a pressure medium can be supplied to or discharged from the first pressure chamber or the second pressure chamber via an electric valve. For example, the at least one first pressure chamber opening and the at least one second pressure chamber opening can be a bore through the wall of the hollow cylinder. The bore can, for example, have an internal thread. The internal thread can be designed such that it can form a pressure-tight connection with an external thread of an electric valve, such that pressure medium can only flow into the first or second pressure chamber through the flow channel within the electric valve.

[0017] Electric valves preferably comprise a valve flow channel and a valve closure part. The pressure medium to be controlled by the electric valve can flow through the valve flow channel. The valve flow channel can be closed with the valve closure part, thus closing the flow path for the pressure medium. When the valve is open, the valve flow channel has a minimum flow cross-section, which preferably determines the maximum fluid flow through the valve. If there is no section (no throttle) with a smaller flow cross-section in the flow channel starting from the pressure accumulator and into the pressure chamber, the minimum flow cross-section of the valve flow channel also determines the maximum fluid flow from the pressure accumulator to the pressure chamber. When the valve is closed, preferably no pressure medium can flow through the valve flow channel.The open state and the closed state of the electric valve preferably refer to the fully (maximum) open state of the electric valve and the fully (maximum) closed state of the electric valve.

[0018] Electric valves, as defined in this disclosure, include all components that serve to shut off or control the flow of fluids (liquids or gases) and are actuated (purely) electrically, for example, via an electromagnet, an electric servomotor with a gear drive, a worm drive, or a linear motor. In particular, solenoid valves are understood to be electric valves.

[0019] Valve closure parts can be designed, for example, as a plate, cone, ball, needle or valve piston, which, in conjunction with a corresponding valve seat, enable the flow channel to be sealed or closed.

[0020] A cylinder-reciprocating piston device according to this disclosure preferably comprises at least two electric valves, which preferably comprise at least one electric valve for supplying or discharging pressure medium from the first pressure chamber and preferably at least one electric valve for supplying or discharging pressure medium from the second pressure chamber. However, in embodiments not covered by the current claims, a single multi-way valve may also be used.

[0021] Compared to mechanical valves, for example, electric valves allow for a simpler, lighter, and less frictional design of the valves, including their drives and controls. Furthermore, the degrees of freedom in adjustment and control are greater.

[0022] For the purposes of this disclosure, compressed air is the pressure medium that can absorb supplied energy due to compression and storage in a pressure tank. The pressure medium can preferably also be supplied to a pressure chamber (first or second) or removed from a pressure chamber, wherein the pressure medium can release at least part of the energy supplied by compression through expansion in the pressure chamber. The expansion of the pressure medium in the pressure chamber builds up pressure in the pressure chamber, which can set the piston in motion. No combustion / ignition is necessary to expand the pressure medium.

[0023] The compressed air motor provides a drive motor that is, for example, simple, compact, safe, and versatile. The use of compressed air as the pressure medium also provides a drive motor with environmentally friendly drive energy. Air as the working medium is unlimited and can be used without overexploiting our resources. Hazardous waste, such as that produced by today's lithium-ion batteries for electric drives, is not generated over the motor's life cycle when compressed air is used as drive energy. Furthermore, when used as an energy source in an air motor, the compressed air is simply compressed without any pollution. This means that the compressed air emitted by an air motor is free of pollutants and can escape into the environment unfiltered, unchanged, and quietly. The compressed air motor can also be used in sensitive areas, for example, because no pollutants are produced and, depending on the design, no oil is required.For example, an air motor can be used advantageously in boats, hospitals, cold storage facilities, airports and train stations, or for vehicles in urban traffic. A compressed air tank, for example, can be recharged using an electrically powered on-board compressor at any outlet or at stationary compressed air stations.

[0024] When used with compressed air, the air motor is characterized by its CO2-neutral operation with zero emissions. The air motor offers a drive system that is simple to manufacture and dispose of, and environmentally friendly.

[0025] An air motor is preferably modularly configurable and can therefore be flexibly adapted to a variety of applications. The cylinder-reciprocating piston devices of the air motor can be arranged in series or parallel as required. Furthermore, different cylinder-reciprocating piston devices can be combined with one another. This allows the air motor to be specifically adapted to the respective performance requirements and the respective application. The cylinder-reciprocating piston device(s) of the air motor can be operated in either a single-stroke or multi-stroke mode, depending on the requirements or operating situation. If necessary, various pressure media, even different from one another, can be used. High torques can be achieved, and the torque generated by the motor can be ideally adapted to the circumstances.For example, an air motor with a single cylinder and reciprocating piston assembly can easily be equivalent to or superior to a conventional four-cylinder, four-stroke engine in terms of performance due to the possibility of single-stroke operation. The production costs of such an air motor are low.

[0026] The pneumatic motor comprises at least two cylinder-reciprocating piston devices according to this disclosure. Furthermore, the pneumatic motor has a piston rod and a crankshaft. The crankshaft and the piston of the at least two cylinder-reciprocating piston devices are coupled such that a (linear) reciprocating movement of the piston is converted into a rotational movement of the crankshaft via the piston rod.

[0027] The piston rod extends through a piston rod opening in the inner wall of the hollow cylinder of the cylinder-reciprocating piston device. Preferably, the piston rod (the outer diameter of the piston rod) and the piston rod opening are matched to one another in such a way that the corresponding pressure chamber through which the piston rod extends is fluid-tightly sealed to the outside. For example, a fluid-tight seal can be achieved via seals / sealing rings in the piston rod opening. The piston rod can extend from the piston on one side through the first pressure chamber or the second pressure chamber to the outside, or alternatively from the piston on both sides through the first pressure chamber and the second pressure chamber.

[0028] Various designs are conceivable for the unit, exemplified as a crank mechanism, preferably comprising a piston, piston rod, connecting rod, crankshaft, and connecting joints. It is preferred that the piston rod performs a linear movement so that a reliable seal can be achieved between the pressure chamber of the cylinder-reciprocating piston device and the outside. It is also possible to combine various different or identical crank mechanisms in an air motor.

[0029] The cylinder-reciprocating piston assembly is dual-acting. Therefore, the piston of the cylinder-reciprocating piston assembly can be pressurized from either one or two opposite sides during power output operation (motor operation). Depending on the power requirements, the operating mode of one or more cylinder-reciprocating piston assemblies of the air motor can be flexibly adjusted.

[0030] Furthermore, the cylinder-reciprocating piston device can be operated in pump mode (recuperation mode). In pump mode, the piston can pressurize a pressure medium. Corresponding to the power output mode (motor mode) described above, pressure can be applied to a pressure medium by the piston on one or both sides. In pump mode, the piston is driven via a drive wheel or a crankshaft coupled to the drive wheel. For example, air at ambient pressure can be sucked into the first pressure chamber by the piston during movement from the first end position to the second end position. During the return movement of the piston from the second end position to the first end position, the electrical valves of the first pressure chamber are preferably closed, so that the pressure medium in the first pressure chamber is compressed.For example, when the piston is at the end of its movement from the second end position to the first end position, the compressed pressure medium is released from the first pressure chamber and can be stored, for example, in a pressure tank.

[0031] Electric valves can be switched very quickly, variably, and precisely. This allows for short actuation times. Furthermore, the electric valves can be controlled specifically and independently of one another using an electronic control system. This allows for a high degree of flexibility in the operation of one or more cylinder-reciprocating piston devices in an air motor.

[0032] Instead of electrical valves, media-operated valves that are pneumatically or hydraulically controlled, or valves that are mechanically operated via the crankshaft can be used.

[0033] According to a further example not covered by the claims, the compressed air motor can be designed as an opposed-piston motor. In an opposed-piston motor, two pistons operate in the same hollow cylinder and share a common pressure chamber in the center of the hollow cylinder. Accordingly, one of the two pistons is connected to a first piston rod that extends outwards through the top wall of the hollow cylinder. The other of the two pistons is connected to a second piston rod that extends outwards through the bottom wall of the hollow cylinder. A crankshaft is each connected to the first piston rod and the second piston rod, which converts the reciprocating movement of the respective piston rod into a rotational movement of the crankshaft. Accordingly, in such a motor, additional valves are provided in the side wall of the hollow cylinder so that the common pressure chamber can be filled and emptied.

[0034] The core of the invention is further to provide compressed air motors together with at least one pressure tank in a vehicle and to advantageously arrange these components in the vehicle.

[0035] A vehicle has one or more compressed air motors and preferably one or more pressure tanks. The pressure tanks are designed to store at least one pressure medium. The pressure tanks can be connected to one another in a communicating manner (in series, parallel, or combined) or, particularly when using different pressure media or different pressures in the respective tanks, not be connected to one another in a communicating manner. Depending on the number of different pressure media used, multiple pressure tanks can be used for different pressure media. When using only one pressure medium, such as compressed air, one large compressed air tank or, alternatively, several small compressed air tanks can be used. For example, a separate pressure tank can also be provided for a recuperation function to separately store the pumped medium.

[0036] According to an exemplary embodiment, different pressure media can also be used for the same compressed air motors in a vehicle according to this disclosure. For example, an air motor can initially be operated with compressed air and, if necessary, switched to operation with, for example, hydrogen. For example, a vehicle according to this disclosure can also have multiple compressed air motors, each operated with its own, different pressure medium. Accordingly, a vehicle according to this disclosure can, for example, have one compressed air motor designed for operation with compressed air and one compressed air motor designed for operation with, for example, hydrogen. By combining different pressure media in one vehicle, a significant increase in range and flexibility in fuel availability can be achieved.

[0037] The result is a very lightweight, energy-efficient, and flexibly driven vehicle. The flexible operation of the cylinder-piston arrangements of an air motor eliminates the need for drivetrain components such as transmissions and differentials. This allows for the creation of vehicles that are very lightweight compared to, for example, conventional combustion engines. The minimal number of drivetrain components makes a vehicle's drivetrain very robust and extremely low-maintenance.

[0038] In a vehicle, the pressure tank, which is designed to be torsionally rigid, can serve as a support for the vehicle body. The compact design of the compressed air motors allows the arrangement of several compressed air motors in the vehicle. For example, each drive wheel can have its own compressed air motor. The individual compressed air motors can also be attached to the compressed air tank. The compact design of the compressed air motor and the possibility of omitting axle drive components such as gearboxes and differentials allow for the flexible implementation of many engine variants and the optimal adaptation of the vehicle's drive to the respective application. The vehicle is also characterized by its high level of safety, because the pressure tank is explosion-proof and non-flammable.

[0039] In a vehicle according to this disclosure, for example, an accelerator pedal and / or a brake pedal may be coupled to the controller of the one or more pneumatic motors such that, by means of the accelerator pedal and / or the brake pedal (via the controller), the states of the electric valves (and thus the supply and discharge and stopping of the supply of compressed air to each of the one or more cylinder-reciprocating piston devices) can be controlled as required (power and speed).

[0040] For example, in a vehicle with at least one compressed air motor, the following four operating states for the states of electric valves of at least one cylinder-reciprocating piston device can be implemented by means of the controller depending on the position of the accelerator pedal, the brake pedal and the speed of the vehicle.

[0041] A first operating state can occur, for example, when the accelerator and brake pedals are not depressed and the vehicle is stationary. In the first operating state, for example, all electrical valves of a cylinder-piston device are closed. The cylinder-piston device thus neither delivers power (engine operation) nor supplies energy to a pressure medium (pump operation). According to the first operating state, the vehicle is preferably in park mode.

[0042] A second operating state can occur, for example, when the accelerator pedal and the brake pedal are not actuated and the vehicle is moving. In the second operating state, for example, all electrical valves of at least one cylinder-reciprocating piston device are closed. In addition, a freewheel is preferably engaged / present, which can decouple the crankshaft, which is coupled to the at least one cylinder-reciprocating piston device, and the drive wheel, which is coupled to this crankshaft, from one another, such that the drive wheel can rotate when the freewheel is engaged and the piston of the cylinder-reciprocating piston device is preferably stationary at the same time. According to the second operating state, the vehicle is preferably in free-rolling mode (freewheel mode).

[0043] A third operating state can occur, for example, when the accelerator pedal is not depressed, but the brake pedal is depressed and the vehicle is moving. In the third operating state, for example, a cylinder-reciprocating piston device operates in recuperation mode (pump mode). In recuperation mode, the electrical valves of a cylinder-reciprocating piston device are preferably switched such that a pressure medium at ambient pressure is first sucked into the first or second pressure chamber by, for example, the downward movement of the piston of the cylinder-reciprocating piston device, then compressed in the corresponding pressure chamber by the opposite movement of the piston, in this case the upward movement, and then discharged from the pressure chamber into the same or another pressure tank.The use of recuperation mode during braking can extend the range, since the cylinder-piston device first pressurizes a pressure medium and the pressurized pressure medium can then be used as a pressure medium for pressurizing the piston of a cylinder-piston device (engine operation).

[0044] For recuperation operation, it may be advantageous to provide a separate pressure tank for the pressure medium compressed by the cylinder-reciprocating piston device. When using a separate pressure tank, for example, the first pressure chamber of a cylinder-reciprocating piston device can be connected to both a first pressure tank and a second pressure tank. The first pressure tank is preferably connected to the first pressure chamber in such a way that the pressure medium from the first pressure tank can be fed to the first pressure chamber via an electric valve. Furthermore, the second pressure tank is preferably connected to the first pressure chamber in such a way that the pressure medium from the second pressure tank can be fed to the first pressure chamber via an electric valve. The second pressure tank is, for example, a tank designed for storing pressure medium compressed by recuperation.The cylinder-reciprocating piston device can be selectively operated with either the first pressure tank or the second pressure tank. For example, an electric 3-way valve can be provided, via which the pressure medium from the first pressure tank or the pressure medium from the second pressure tank can be selectively supplied to the first pressure chamber. The second pressure tank is furthermore preferably designed such that it can receive and store a pressure medium that has been compressed in the cylinder-reciprocating piston device by the piston. The pressure medium stored in the second pressure tank can have a lower pressure than the pressure medium from the first pressure tank. The pressure medium from the second pressure tank can then be called up, for example, when the vehicle's power requirements are low. Such a second pressure tank can also be present independently of the recuperation function.

[0045] A fourth operating state can occur, for example, when the accelerator pedal is depressed and the brake pedal is not depressed. The vehicle can be stationary or moving. It can therefore be starting off or accelerating. In the fourth operating state, the one or more cylinder-reciprocating piston devices are filled with the pressure medium via electric valves or the pressure medium is discharged from them. At full load (accelerator pedal fully depressed), for example, all cylinder-reciprocating piston devices of the one or more compressed air motors in the vehicle can be switched on. At low power (accelerator pedal partially depressed), for example, only individual cylinder-reciprocating piston devices can be supplied with pressure medium or discharged from them. Furthermore, depending on the power requirement, operation can be carried out in single-stroke or multi-stroke mode.

[0046] A vehicle according to this disclosure is characterized by an extremely high degree of flexibility in the arrangement and design of the pressure tanks and the compressed air motors. Due to the flexible design of the cylinder-piston devices of each compressed air motor, additional components of a conventional drive train, such as transmissions and differentials, can preferably be dispensed with.

[0047] According to a further example, the vehicle speed can be adjusted by using multiple drive wheels with different diameters. According to this example, an air motor is preferably connected to a large drive wheel of the vehicle and a air motor to a smaller drive wheel of the vehicle. If high speeds are to be achieved, the air motor of the large drive wheel can be switched on and the air motor of the smaller drive wheel switched off, or an additional freewheel can be switched between the air motor of the smaller drive wheel and the smaller drive wheel. Conversely, at low speeds, only the air motor for the smaller drive wheel is switched on and the air motor for the large drive wheel switched off or decoupled via a freewheel.If high speeds are required, the air motor of the large drive wheel can be switched on. As long as both air motors rotate at the same maximum speed, the larger diameter of the large drive wheel compared to the smaller drive wheel allows the vehicle to reach higher speeds.

[0048] According to an exemplary embodiment, the piston stroke of the cylinder-reciprocating piston device is smaller than the piston outer diameter.

[0049] The piston stroke is the distance traveled by the piston between the first and second end positions. The piston outer diameter is the outer diameter of the (cylindrical) piston, which is matched to the hollow cylinder in such a way that the piston can be moved within the hollow cylinder without pressure. The piston outer diameter is therefore the maximum diameter of the piston.

[0050] According to the exemplary embodiment above, the cylinder-reciprocating piston device is a short-stroke device. Compared to long-stroke devices of the same displacement, i.e., cylinder-reciprocating piston devices in which the piston stroke is greater than the piston's outer diameter, a short-stroke device provides more space in the top or bottom wall of the hollow cylinder for larger valves. This allows for a higher pressure medium throughput and thus more torque and power. An air motor with such a cylinder-reciprocating piston device can be designed very compactly while still achieving high performance.

[0051] According to an exemplary embodiment, the cylinder-reciprocating piston device has a first dead space volume when the piston is in the first end position, which is less than 30%, preferably less than 15%, more preferably less than 5%, more preferably less than 2.5%, more preferably less than 1% of the first displacement volume. And the cylinder-reciprocating piston device has a second dead space volume when the piston is in the second end position, which is less than 30%, preferably less than 15%, more preferably less than 5%, more preferably less than 2.5%, more preferably less than 1% of the second displacement volume.

[0052] The first displacement volume is determined by the piston stroke and the effective cross-sectional area of ​​the piston relative to the first pressure chamber.

[0053] The second displacement volume is determined by the piston stroke and the effective cross-sectional area of ​​the piston relative to the second pressure chamber.

[0054] The effective cross-sectional area of ​​the piston is the surface of the piston facing the top wall or bottom wall, which borders the first pressure chamber downwards or the second pressure chamber upwards. In other words, the effective cross-sectional area is the projection of the surface of the piston facing the top wall or bottom wall onto a surface perpendicular to the direction of movement of the piston. Accordingly, the area to which a piston rod is connected is not included in the effective cross-sectional area. In simplified terms, the effective cross-sectional area is therefore the cross-sectional area of ​​the piston (including any sealing rings) minus the cross-sectional area of ​​any piston rod present.

[0055] The first dead space volume is the volume located between the piston in its first end position and the electric valves in the closed position, through which the first pressure medium can be supplied to and / or discharged from the first pressure chamber. With regard to the electric valves, the valve closure part, which is in the closed position, should be used as a reference.

[0056] The first dead space volume is thus formed, on the one hand, by the volume of the first pressure chamber when the piston is in the first end position. On the other hand, the first dead space volume is formed by the volume that can be filled with the pressure medium and is formed between the valve closure part of the at least one electric valve in the closed state, via which the first pressure medium can be supplied to and / or discharged from the first pressure chamber, and the first pressure chamber. The latter can also be referred to as the valve channel volume facing the pressure chamber.

[0057] The second dead space volume is the volume located between the piston in its second end position and the electric valves through which the second pressure medium can be supplied to and / or discharged from the second pressure chamber. With regard to the electric valves, the valve closure part, which is in the closed state, should be used as a reference.

[0058] The second dead space volume is thus formed, on the one hand, by the volume of the second pressure chamber when the piston is in the first end position. Additionally, the second dead space volume is formed by the volume that can be filled with the pressure medium and is formed between the valve closure part of the at least one electric valve in the closed state, via which the second pressure medium can be supplied to and / or discharged from the first pressure chamber, and the second pressure chamber. The latter can also be referred to as the valve channel volume facing the pressure chamber.

[0059] The dead space volume thus refers to a state of the cylinder-piston device in which all electric valves for the inlet and outlet of the pressure medium into the first and second pressure chambers, respectively, are closed and the piston is in either the first or second end position. Such an operating state can, for example, be the state of the electric valves when the vehicle is stationary.

[0060] It has been found that a dead space volume that is less than 30%, preferably less than 15%, more preferably less than 5%, more preferably less than 2.5%, and more preferably less than 1% of the first displacement volume has a positive effect on the piston's response behavior. The small dead space volume ensures that the medium introduced into the first pressure chamber or second pressure chamber exerts a pressure force on the piston that corresponds to the pressure of the pressure medium after a very short time. Compared to larger dead space volumes, prior compression of the gas contained in the dead space volume is not necessary.

[0061] According to an exemplary embodiment, the at least one first pressure chamber opening is arranged in the ceiling wall and the at least one second pressure chamber opening is arranged in the floor wall.

[0062] Such an arrangement of the at least one first pressure chamber opening and the at least one second pressure chamber opening allows the piston to be brought into close proximity or contact with the ceiling wall or the bottom wall.

[0063] With such an arrangement, the piston cannot close off any of the at least one first pressure chamber opening or the at least one second pressure chamber opening in the radial direction, as these are arranged in the bottom wall or the top wall, respectively. For openings arranged in the outer surface of the hollow cylinder inner wall, the piston must not completely block the openings to ensure reliable supply and removal of the pressure medium from the pressure chamber. Therefore, the piston cannot be brought into direct proximity with or into contact with the bottom wall or the top wall. Furthermore, if the first pressure chamber openings and / or second pressure chamber openings are arranged in the outer surface of the hollow cylinder inner wall, the efficiency of the cylinder-reciprocating piston device may be reduced if the piston blocks the at least one first pressure chamber opening or the at least one second pressure chamber opening.

[0064] According to the above explanation, the proportion of the dead space volume determined by the first pressure chamber or the second pressure chamber when the piston is in the end position can be minimized.

[0065] Particularly when the cylinder-piston device is designed as a short-stroke unit, there is plenty of space in the ceiling or base wall of the hollow cylinder for electric valves. Depending on the specific application, it may be advantageous to control the supply and discharge of pressure medium into and out of the pressure chamber with a few large or many small electric valves. Smaller electric valves, for example, are characterized by very short switching times. Large valves, for example, can achieve a high volume flow through the valve.

[0066] According to an exemplary embodiment, each of the multiple pressure chamber openings (for the first and second pressure chambers and for the supply and discharge of pressure medium) is preferably assigned its own electric valve. The number of electric valves therefore corresponds to the sum of all pressure chamber openings for the supply and discharge of pressure medium into the first and second pressure chambers. By arranging or assigning electric valves in this way, the electric valves can be arranged very close to the first pressure chamber or the second pressure chamber, since each pressure chamber opening for the supply and discharge of pressure medium has its own electric valve. Accordingly, a very small dead space volume can be achieved. Furthermore, by assigning them in this way, the inlet and outlet of pressure medium into the first and second pressure chambers can be controlled separately from one another.This results in a maximum degree of flexibility and thus a high degree of adaptability of the engine's performance to the respective operating condition or the respective load situation and / or power requirement in the respective operating situation.

[0067] According to an exemplary embodiment, electric valves with a relatively large minimum flow cross-section in relation to the effective cross-sectional area of ​​the piston are used. This allows the throughput of pressure medium supplied to or discharged from the pressure chamber to be very high, thus achieving high engine performance. Preferably, the cross-sectional areas of the remaining flow paths between the pressure tank, which contains the pressure medium for the cylinder-reciprocating piston device, and the corresponding cylinder-reciprocating piston device are each larger than the minimum flow cross-section of the valve. Thus, the minimum flow cross-section of the valve is preferably also the minimum flow cross-section of the remaining flow paths between the pressure tank and the cylinder-reciprocating piston device.

[0068] Preferably, the pressure medium discharged from the first pressure chamber or the second pressure chamber is less compressed during power output operation (engine operation) than the pressure medium entering the first pressure chamber or the second pressure chamber. In order to equalize the flow velocities of incoming and outgoing pressure media, for example, according to an exemplary embodiment, the sum of the minimum flow cross sections of the electric valves responsible for discharging the pressure medium is preferably increased relative to the electric valves responsible for admitting pressure medium.

[0069] According to an exemplary embodiment, the cylinder-reciprocating piston device has at least two inlet first pressure chamber openings and at least two outlet first pressure chamber openings. Furthermore or alternatively, the cylinder-reciprocating piston device has at least two inlet second pressure chamber openings and at least two outlet second pressure chamber openings.

[0070] Preferably, the at least two first pressure chamber openings (inlet and outlet) and the at least two second pressure chamber openings (inlet and outlet) are arranged symmetrically with respect to the rotational axis of the pressure chamber. By using multiple first or second pressure chamber openings, the amount of pressure medium supplied to the pressure chamber can be increased. If, according to an exemplary embodiment, each opening of the first or second pressure chamber openings has its own electric valve, all or only a number of the openings can be opened using the controller and individual control of the electric valves. Thus, the amount of pressure medium supplied to the pressure chamber can be flexibly adjusted using the controller.

[0071] According to an exemplary embodiment, the cylinder-reciprocating piston device preferably has a pressure sensor for measuring a pressure and / or a temperature sensor for measuring a temperature. Preferably, only one pressure sensor is provided in the first pressure chamber or the second pressure chamber. Alternatively, a pressure sensor can be provided in each of the first pressure chamber and the second pressure chamber. Preferably, only one temperature sensor is provided in the first pressure chamber or the second pressure chamber. Alternatively, a temperature sensor can be provided in each of the first pressure chamber and the second pressure chamber. Alternatively, further sensors can be provided in one of the first and the second pressure chamber or in each of the first and the second pressure chamber.

[0072] According to an exemplary embodiment, the compressed air motor has at least one pressure regulator. Preferably, a pressure regulator is arranged between the respective pressure tank, in which the respective pressure medium for a respective cylinder-reciprocating piston device is located, and the corresponding cylinder-reciprocating piston device. In order to reduce, for example, high pressures in a pressure tank to lower pressures for supply, several pressure regulators in the form of reducing valves can be provided as pressure reduction stages. If necessary, additional intermediate pressure tanks are also provided. According to this embodiment, it is possible, for example, to increase or decrease the pressure of the pressure medium flowing from the pressure tank to the pressure regulator using the pressure regulator and then to supply it to the cylinder-reciprocating piston device.The pressure of the pressure medium influences the power output of the cylinder-reciprocating piston device, since at high pressure more force can be exerted on the piston of the cylinder-reciprocating piston device. The pressure regulator preferably has different output lines (output flow paths) in which the pressure of the pressure medium can differ. Thus, with one pressure regulator, several cylinder-reciprocating piston devices can be supplied with a pressure medium with different pressures regulated by the pressure regulator. This design provides a very high degree of flexibility for the operation of the individual cylinder-reciprocating piston devices of an air motor. With the help of the pressure regulator, the pressure in each of the first pressure chambers and the second pressure chambers can be individually adjusted, preferably in an air motor with several cylinder-reciprocating piston devices.

[0073] According to an exemplary embodiment, the pneumatic motor has a rotation angle sensor for detecting the rotational position of the crankshaft.

[0074] Furthermore, the pneumatic motor according to the above embodiment comprises a control system. The control system is preferably an electronic control system. The control system can be used to control the multiple electric valves of the cylinder-reciprocating piston device, for example, such that the cylinder-reciprocating piston device can be switched, as needed, between single-stroke operation, in which the piston is pressurized during each movement between the end positions, or multi-stroke operation, in which the piston is not pressurized during individual movements between the end positions.

[0075] The controller is designed to control the electric valves of the one or more cylinder-piston devices, i.e., to open and close them. The input variable for the controller is preferably a signal from one or more angle of rotation sensors, which can determine the rotational position of the one or more crankshafts and transmit this value to the controller. Using this input variable, the controller can determine the position of the pistons connected to the corresponding crankshaft on which the angle of rotation sensor is located.

[0076] For example, the control can be designed so that a rotation angle of the crankshaft of 0° or 360° corresponds to a position of the piston in the first end position and a rotation angle of 180° corresponds to a position of the piston in the second end position.

[0077] The following example describes the control of the electric valves for the case where the electric valves are opened or closed precisely when the piston is in the first end position or the second end position. Alternatively, opening / closing can occur at any other time, depending on the load situation.

[0078] In the first end position of the piston, the volume of the first pressure chamber is at a minimum and the volume of the second pressure chamber is at a maximum. The control system uses the crankshaft's rotation angle sensor to detect that the piston is in the first end position and opens the electric valve through which the first pressure medium can be fed into the first pressure chamber and closes the electric valve through which the first pressure medium can be discharged from the first pressure chamber. The control system also opens the electric valve through which the second pressure medium can be discharged from the second pressure chamber and closes the electric valve through which the second pressure medium can be fed into the second pressure chamber. Depending on the states of the electric valves, the first pressure medium is fed to the first pressure chamber, the first pressure medium builds up pressure in the first pressure chamber and thus pushes the piston from the first end position towards the second end position of the piston.The piston then reaches the second end position.

[0079] In the second end position, the volume of the second pressure chamber is at its minimum and the volume of the first pressure chamber is at its maximum. The control system uses the crankshaft's rotation angle sensor to detect that the piston is in the second end position and, when the piston is in the second end position, opens the electric valve through which the second pressure medium can be fed into the second pressure chamber and closes the electric valve through which the second pressure medium can be discharged from the second pressure chamber. Furthermore, the control system opens the electric valve through which the first pressure medium can be discharged from the first pressure chamber and closes the electric valve through which the first pressure medium can be fed into the first pressure chamber.

[0080] The control system preferably allows the electric valves to be opened and closed in a manner different from that outlined above, in which the opening and closing of the electric valves takes place exactly at a crank angle of 0° / 180° / 360° or exactly in the first end position or in the second end position.

[0081] For example, when the piston moves from the second end position to the first end position, the electric valve through which the first pressure medium can be fed into the first pressure chamber can already be opened, and the electric valve through which the first pressure medium can be discharged from the first pressure chamber can already be closed before the piston reaches the first end position, preferably at a crankshaft rotation angle of 330°-359°, more preferably of 345°-355°. A crankshaft rotation angle of 0° / 360° corresponds in this example to the position of the piston in the first end position. A crankshaft rotation angle of 180° corresponds in this example to the position of the piston in the second end position.In addition, the electric valve, via which the second pressure medium can be fed into the second pressure chamber, is already closed, and the electric valve, via which the second pressure medium can be discharged from the second pressure chamber, is already opened, before the piston reaches the first end position, preferably at 330°-359°, more preferably at 345°-355°.

[0082] Preferably, the piston moves (immediately after the above-described opening and closing of the electric valves) to the first end position (360° crankshaft rotation angle) due to the inertia of the entire crank mechanism, of which the piston is a part. Once the piston is in the first end position, a higher pressure immediately acts on the piston, pushing it back to its second end position, compared to a case where the electric valves open and close at 360°.

[0083] In accordance with the control times for the first end position described above as an example, the control times for the second end position are preferably also adjusted. For the second end position, a control time for opening or closing the electric valves is accordingly obtained at preferably 150°-179°, more preferably 165°-175°. This control time is before the second end position of the piston, when the piston moves from the first end position to the second end position. At this control time, the electric valve, via which the second pressure medium can be fed into the second pressure chamber, and the electric valve, via which the first pressure medium can be discharged from the first pressure chamber, are opened. In addition, the electric valve, via which the second pressure medium can be discharged from the second pressure chamber, and the electric valve, via which the first pressure medium can be fed into the first pressure chamber are closed.

[0084] The controller is preferably powered by a vehicle power source. With multiple cylinder-reciprocating piston devices, the controller can be connected to each of the multiple cylinder-reciprocating piston devices in such a way that it can open and close each of the electric valves of the multiple cylinder-reciprocating piston devices independently of one another. This allows for a very broad range of applications and great flexibility of the pneumatic motor.

[0085] According to another exemplary embodiment of the control system, the control timing can be variably adjusted so that the times for opening and closing the electric valves differ from one another in order to achieve the lowest consumption with the best power output. In particular, the control timing can be variably changed or adjusted during operation.

[0086] For example, with respect to the first end position and with a piston moving from the second end position to the first end position, the electric valve through which the pressure medium can be fed into the first pressure chamber can be opened at a crankshaft rotation angle of 330°-359°, more preferably at 345°-355°, and the electric valve through which the pressure medium can be discharged from the first pressure chamber can then be closed, offset by a crankshaft rotation angle in the range of 0.11° to 10°, preferably 1° to 7°, crankshaft rotation angle. For example, the electric valve through which the pressure medium can be fed into the first pressure chamber could be opened at a crankshaft rotation angle of 355°, and the electric valve through which the pressure medium can be discharged from the first pressure chamber could then be closed, offset by 1° crankshaft rotation angle, for example, at a crankshaft rotation angle of 356°.

[0087] The same applies, of course, to the electrical valves of the second pressure chamber in relation to the second end position.

[0088] The control system can operate a cylinder-piston device in single-stroke or multi-stroke operation.

[0089] In single-stroke operation, the piston is pressurized during each movement between the first end position and the second end position. In other words, a pressure medium is alternately supplied to the first pressure chamber to push the piston toward the second end position, and a pressure medium is supplied to the second pressure chamber to push the piston from the second end position back to the first end position.

[0090] In multi-stroke operation, however, the piston is not pressurized during every stroke. For example, in a cylinder-reciprocating piston device, the electric valve through which the second pressure medium is discharged from the second pressure chamber can always be open, so that ambient pressure prevails in the second pressure chamber. Accordingly, no pressure medium is supplied to the second pressure chamber. For example, whenever the piston is in (or near) the first end position, pressure medium is supplied to the first pressure chamber. The pressure medium is therefore supplied to the first pressure chamber with every second stroke of the piston. Accordingly, this example represents multi-stroke operation, namely time-cycled operation of the cylinder-reciprocating piston device.

[0091] According to an exemplary embodiment, the direction of rotation of the crankshaft can be reversed with the aid of the control.

[0092] Preferably, the control system detects the position (crankshaft rotation angle) of the crankshaft when the vehicle is stationary. Optionally, the control system can control the electric valves in such a way that pressure medium is either initially supplied to the first pressure chamber or initially supplied to the second pressure chamber. Depending on the selected pressure chamber, the piston can be moved upwards or downwards from the stationary position. Depending on whether the piston moves upwards or downwards, the crankshaft rotates clockwise or counterclockwise. This corresponds to the vehicle moving forwards or backwards.

[0093] The pneumatic motor comprises at least two of the cylinder-reciprocating piston devices having a common piston rod connected to each of the pistons of the reciprocating devices.

[0094] Accordingly, several cylinder-reciprocating piston devices are connected in series. In other words, the pistons of the at least two cylinder-reciprocating piston devices are connected to the same piston rod, so that the pistons move up and down synchronously. The stroke heights of the at least two cylinder-reciprocating piston devices are accordingly identical. The stroke volume, however, can differ, for example, due to different outer diameters of the respective pistons of the at least two cylinder-reciprocating piston devices. Accordingly, for example, the pistons of the at least two cylinder-reciprocating piston devices jointly push the piston rod downwards or upwards. The piston rod is connected to a crankshaft.

[0095] The at least two cylinder-reciprocating piston devices can be identical or differ, for example, in terms of the effective cross-sectional area of ​​the pistons. The at least two cylinder-reciprocating piston devices are arranged on the same side relative to the connection between the crankshaft and piston rod. This allows the pneumatic motor to be flexibly adapted to the respective spatial requirements.

[0096] According to an exemplary embodiment, the pneumatic motor has at least two cylinder-reciprocating piston devices, each with a piston rod. Each piston rod is connected to the same crankshaft. According to this embodiment, several cylinder-reciprocating piston devices are connected in parallel.

[0097] In contrast to the above-mentioned series connection of cylinder-reciprocating piston devices, where the stroke height is always identical, the stroke height can vary with cylinder-reciprocating piston devices connected in parallel. Greater stroke heights can be achieved, for example, by making the crank arms of the common crankshaft, to which the respective piston rod is connected, longer. This places the connection between the piston rod and crank arm radially further away from the axis of rotation of the crankshaft than with a short crank arm. For half a revolution of the crankshaft, the longer crank arm results in a correspondingly greater stroke of the piston rod. In this way, different strokes of cylinder-reciprocating piston devices can be realized with one crankshaft and different crank arms.

[0098] For example, the compressed air engine can be constructed in the form of a radial engine, boxer engine, opposed piston engine, V-engine, etc. In a radial engine, the multiple cylinder-reciprocating piston devices are arranged radially around the crankshaft, for example.

[0099] According to an exemplary embodiment, the at least two cylinder-reciprocating piston devices, and / or the piston rods and / or the crank arms of the crankshaft to which the piston rods are connected, are designed differently. Thus, the at least two cylinder-reciprocating piston devices can be provided with different displacement volumes and / or stroke heights.

[0100] For example, in series-connected cylinder-piston devices, the effective cross-sectional areas (especially the piston outer diameters) may differ.

[0101] In the case of cylinder-piston devices connected in parallel, the stroke heights can, for example, differ due to different lengths of the crank arms of the common crankshaft, at the end of which the piston rod is connected to the crankshaft.

[0102] According to this embodiment, it is possible to design and coordinate the cylinder-reciprocating piston devices of an air motor so flexibly that a compressed air motor optimally tailored to the respective application can be provided. The various cylinder-reciprocating piston devices can be different and can be switched off independently of one another.

[0103] According to an exemplary embodiment, the pressure of the first and / or second pressure medium in each of the first and second pressure chambers of the at least two cylinder-reciprocating piston devices can be adjusted independently of one another. In particular, the at least two cylinder-reciprocating piston devices can be switched off independently of one another. Furthermore, they can preferably also be filled with different media and / or different pressures.

[0104] For example, the pressure in each pressure chamber can be adjusted using a pressure regulator located between the first or second pressure chamber and the pressure tank. For example, in such a design, the cylinder-reciprocating piston device can be operated in multi-stroke mode using only the first pressure medium or only the second pressure medium. Additionally, a cylinder-reciprocating piston device can be selectively deactivated. Deactivated means, for example, that the electrical valves of the corresponding cylinder-reciprocating piston device remain closed and no pressure medium is supplied to the cylinder-reciprocating piston device.

[0105] According to an exemplary embodiment, the first pressure media of the at least two cylinder-reciprocating piston devices are at least partially different from one another. For example, the cylinder-reciprocating piston devices can be connected to different pressure tanks or to different regions of a pressure tank.

[0106] Additionally or alternatively, the second pressure media of the at least two of the cylinder-reciprocating piston devices are at least partially different from each other.

[0107] Such an embodiment offers high flexibility of the printing media used, which can be changed depending on availability and flash or intended use.

[0108] According to an exemplary embodiment, the controller controls the plurality of electric valves of a plurality of cylinder-reciprocating piston devices such that at least two of the cylinder-reciprocating piston devices operate with different cycles and / or operate with different pressure differences between the first and second pressure chambers in the first and second end positions and / or can be switched off independently of one another.

[0109] According to an exemplary embodiment, the control system determines the control times of the multiple electric valves depending on a load situation. The load situation is determined, for example, by the load demand (accelerator pedal), pressure, and engine speed.

[0110] Valve timing is the point in time at which the valve closure elements open the valve flow channels of the electric valves for the supply or discharge of the first or second pressure medium into the first or second pressure chamber. Adjusting the valve timing allows for an increase in engine efficiency, depending on the respective load behavior. This increase can result in increased power and torque, as well as fuel savings.

[0111] According to an exemplary embodiment, the piston rod is guided linearly and then connected to the crankshaft via a connecting rod. This embodiment ensures that the pressure chamber can be reliably sealed from the outside. Reliable sealing is possible through the purely linear up-and-down movement of the piston rod. Any possible crank operation that realizes a linear up-and-down movement of the piston rod can be used preferentially.

[0112] According to an exemplary embodiment, in a vehicle according to the present disclosure, the at least one pressure tank serves as a support for the vehicle body and / or the chassis. The at least one pressure tank can be formed integrally by load-bearing body components and / or as a centrally extending beam.

[0113] This type of vehicle design allows for a very compact and rigid construction. The pressure tank serves both to store the pressure medium and also as a support for the vehicle body. Alternatively, the pressure tank can be integrally formed from body components. For this purpose, a large pressure tank can be positioned centrally in the longitudinal direction of the vehicle. Alternatively or additionally, several smaller pressure tanks can be arranged.

[0114] Furthermore, one or more pressure tanks can be carried, for example, in a trailer or similar.

[0115] Multiple air motors can be used in a vehicle. The multiple air motors can be located at different points in the vehicle. Several can also be arranged in a common housing.

[0116] According to an exemplary embodiment, the vehicle has a freewheel. The freewheel interrupts the power flow between an air motor and a drive wheel, allowing the air motor to be switched off while the vehicle is moving.

[0117] The freewheel can be designed so that it can be engaged both when the vehicle is moving forward and when it is moving backward, allowing the pneumatic motor to be switched off both when the vehicle is moving forward and when it is moving backward. The freewheel can also be equipped with an optionally switchable gear ratio.

[0118] Exemplary embodiments of the invention are explained below with reference to the figures. Fig. 1 shows a schematic structure of a cylinder-piston device according to a first embodiment with a piston in the central position. Fig. 2 shows the Fig. 1 marked area A in an enlarged schematic representation. Fig. 3 shows a schematic structure of a cylinder-reciprocating piston device according to a further embodiment with a piston in the first end position, electric valves in the closed position and a piston rod connected to the piston to represent the first dead space volume and the second dead space volume. Fig. 4 shows a schematic structure of a pneumatic motor not according to the invention, in which the piston is in the second end position. Fig. 5 shows the Fig. 4 shown pneumatic motor, in which the piston is in the first end position. Fig. 6 shows a non-inventive and two inventive embodiments of a compressed air motor in a schematic representation. Fig. 7 shows a vehicle according to a first embodiment in a schematic representation.

[0119] Fig. 1 shows a cylinder-reciprocating piston device according to a first embodiment with a piston in the center position. The cylinder-reciprocating piston device 1 has a hollow cylinder 5 with the rotation axis R. The hollow cylinder 5 is closed at the top and bottom. The hollow cylinder inner wall 10 of the hollow cylinder 5 forms a pressure chamber 20. A jacket surface 25 delimits the pressure chamber 20 in the radial direction. A top wall 30 delimits the pressure chamber 20 in the axial direction upwards. A bottom wall 40 delimits the pressure chamber 20 in the axial direction downwards. The piston 15 is located in the pressure chamber 20. The piston 15 is located in Fig. 1 approximately centrally between the top wall 30 and the bottom wall 40. The piston 15 divides the pressure chamber 20 into a first pressure chamber 55, which lies between the piston 15 and the top wall 30, and a second pressure chamber 60, which lies between the piston 15 and the bottom wall 40. The piston 15 is movably arranged in the pressure chamber 20. Depending on the position of the piston 15, the volume of the first pressure chamber or the second pressure chamber changes.

[0120] Two first pressure chamber openings 35 are located in the ceiling wall 30 of the hollow cylinder 5. The left of the two first pressure chamber openings 35 shown is an inlet first pressure chamber opening 36, through which a pressure medium can be fed into the first pressure chamber 55. The right of the two first pressure chamber openings 35 shown is an outlet first pressure chamber opening 37, through which a pressure medium can be discharged or expelled from the first pressure chamber.

[0121] Two second pressure chamber openings 45 are located in the bottom wall 40 of the hollow cylinder 5. The left of the two second pressure chamber openings 45 shown is an inlet second pressure chamber opening 46, through which a pressure medium can be fed into the second pressure chamber 60. The right of the two second pressure chamber openings 45 shown is an outlet second pressure chamber opening 47, through which a pressure medium can be discharged or expelled from the second pressure chamber 60.

[0122] Furthermore, a piston rod opening 50 is located in the bottom wall 40. A piston rod can be guided from the outside into the pressure chamber 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 inlet second pressure chamber opening 46, and the outlet second pressure chamber opening 47. The electric valve 65 is shown in a simplified manner in each case.

[0123] Fig. 2 shows the Fig. 1 marked area A in an enlarged schematic representation. In the ceiling wall 30 of the hollow cylinder 5 are the inlet first pressure chamber opening 36 and the outlet first pressure chamber opening 37.

[0124] An electric valve 65 is shown schematically, which is inserted into the inlet first pressure chamber opening 36. The electric valve 65 is inserted fluid-tight into the inlet first pressure chamber opening 36. The electric valve 65 comprises a valve flow channel 66, which can be closed by means of a valve closure part 67. The valve closure part 67 of the inlet first pressure chamber opening 36 is in the open position. When the valve closure part 67 is in the open position, the flow channel 66 has a minimal flow cross-section 68. The representation of the valve and in particular of the valve closure part 67 is to be understood as a schematic representation that serves to clarify the relevant features of the electric valve.

[0125] An electric valve 65 is shown schematically, which is inserted into the outlet first pressure chamber opening 37. The electric valve 65 is inserted in a fluid-tight manner into the outlet first pressure chamber opening 37. The electric valve 65 comprises a valve flow channel 66, which can be closed by means of a valve closure part 67. The valve closure part 67 of the outlet first pressure chamber opening 36 is in the closed position. The flow channel 66 is thus blocked.

[0126] Fig. 3 shows a cylinder-reciprocating piston device according to a further embodiment with a piston 15 in the first end position, electric valves in the closed position and a piston rod 70 connected to the piston for representing the first dead space volume and the second dead space volume.

[0127] The condition shown in Fig. 3 can, for example, correspond to the state when the vehicle is stationary. The electric valves 67 are all in the closed position. Piston 15 is in the first end position TDC. The dashed line shows piston 15, also in the second end position BDC. Between the first end position TDC and the second end position BDC, piston 15 moves with stroke H. Piston 15 has an outer piston diameter DK.

[0128] The volume that can be filled with pressure medium and is located between the valve closure part 67 of the inlet first pressure chamber opening 36 in the closed position and the valve closure part 67 of the outlet first pressure chamber opening 37 in the closed position and the piston 15 is the first dead space volume 56.

[0129] The first dead space volume 56 is therefore composed, on the one hand, of the volume of the first pressure chamber 55, which is formed when the piston 15 is in the first end position TDC, and, on the other hand, of the volume that can be filled with pressure medium and is located between the valve closure part 67 of the inlet first pressure chamber opening 36, which is in the closed position, and the valve closure part 67 of the outlet first pressure chamber opening 37, which is in the closed position, and the first pressure chamber 55. The first dead space volume 56 is in the Fig. 3 shown in dotted lines above the piston 15.

[0130] The volume that can be filled with pressure medium and is located between the valve closure part 67 of the inlet second pressure chamber opening 46 in the closed position and the valve closure part 67 of the outlet second pressure chamber opening 47 in the closed position and the piston 15 is the second dead space volume 57.

[0131] The second dead space volume 57 is therefore composed, on the one hand, of the volume of the second pressure chamber 60, which is formed when the piston 15 is in the second end position BDC, and, on the other hand, of the volume that can be filled with pressure medium and is located between the valve closure part 67 of the inlet second pressure chamber opening 46, which is in the closed position, and the valve closure part 67 of the outlet second pressure chamber opening 47, which is in the closed position, and the second pressure chamber 60. The second dead space volume 57 is in the Fig. 3 shown in dotted lines below the piston 15.

[0132] Fig. 4 shows a pneumatic motor according to an embodiment not according to the invention, in which the piston is in the second end position BDC. The pneumatic motor comprises a cylinder-reciprocating piston device. A piston rod 70 is connected to the piston 15 of the cylinder-reciprocating piston device 1. The piston rod 70 is connected to two crankshafts 75 via a connecting rod 71 each. Fig. 4 The crank mechanism shown is a so-called double crank mechanism. The piston rod 70 extends through the piston rod opening 50 of the cylinder-reciprocating piston device.

[0133] The piston rod opening 50 is sealed against the piston rod 70 with seals 79.

[0134] Arrows are in the Fig. 4 the flow direction of the pressure medium into the first pressure chamber and out of the second pressure chamber is indicated. Fig.4 The state shown corresponds to a state in which the pressure medium is supplied through the supply first pressure chamber opening 36 into the first pressure chamber 55 and at the same time the pressure medium from the second pressure chamber 60 is discharged from the outlet second pressure chamber opening 47.

[0135] The Fig. 4 The state shown corresponds to an exemplary control state of the electric valves, in which the electric valves are switched exactly in the first end position or in the second end position. The control times thus correspond to a crank angle position of 0° / 180° / 360°.

[0136] The outlet first pressure chamber opening 37 and the supply second pressure chamber opening 46 are each closed by an electric valve 65 with the valve closure part 67 in the closed position. The piston moves through such a flow of pressure media in the first pressure chamber 55 or the second pressure chamber 60 into its second end position UT. The Fig.4 The piston 15 shown has just reached its second end position, BDC. This state is followed by the switching of the valves from "open" to "closed" or from "closed" to "open."

[0137] Fig. 5 shows a state in which the piston 15 is in the first end position TDC. Arrows in the Fig. 5 the flow direction of the pressure medium into the first pressure chamber and out of the second pressure chamber is indicated. Fig. 5 The state shown corresponds to a state in which the pressure medium is supplied through the supply second pressure chamber opening 46 into the second pressure chamber 60 and at the same time the pressure medium from the first pressure chamber 60 is discharged from the outlet first pressure chamber opening 37.

[0138] The supply first pressure chamber opening 36 and the outlet second pressure chamber opening 47 are each closed by an electric valve 65 with the valve closure part 67 in the closed position.

[0139] The piston 15 moves through such a flow of pressure media in the first pressure chamber 55 or the second pressure chamber 60 into its first end position TDC. Fig. 5 The piston shown is already in the first end position TDC.

[0140] Fig. 6 shows a non-inventive and two inventive embodiments of a compressed air motor in a schematic view. I shows a non-inventive

[0141] Compressed air motor with two cylinder-reciprocating piston devices.

[0142] The two cylinder-reciprocating piston devices 1 are connected to two crankshafts 75 via a common piston rod 70. The two cylinder-reciprocating piston devices 1 are located on opposite sides of the crankshafts 75. The two cylinder-reciprocating piston devices 1 are of equal size. II shows an inventive

[0143] Compressed air motor with three cylinder reciprocating piston devices.

[0144] The three cylinder-reciprocating piston devices 1 are connected to 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 different sizes but have the same stroke. III shows an inventive

[0145] Compressed air motor with ten cylinder reciprocating piston devices.

[0146] The compressed air motor has two crankshafts 75 arranged next to each other (corresponding to the design in I and II).

[0147] Four of the ten cylinder-reciprocating piston devices 1 are connected to the crankshafts 75 via a common first piston rod 70. A further four of the ten cylinder-reciprocating piston devices 1 are connected to the crankshafts 75 via a common second piston rod 70. A further two of the ten cylinder-reciprocating piston devices 1 are connected to the crankshafts 75 via a common third piston rod 70. The two cylinder-reciprocating piston devices 1, which are connected to the third piston rod 70, have a greater stroke height than the remaining eight cylinder-reciprocating piston devices. Greater stroke heights can be achieved by making the crank arms of the crankshaft to which the respective piston rod is connected longer, thus placing the connection between the piston rod and the crank arm radially further away from the axis of rotation of the crankshaft than with a short crank arm.For half a revolution of the crankshaft, the longer coupling arm results in a correspondingly greater piston rod stroke. This allows different cylinder-piston arrangements to be realized using one crankshaft and different coupling arms.

[0148] Fig. 7 shows a vehicle according to a first embodiment in a schematic representation.

[0149] Fig. 7 shows a vehicle 150 with four drive wheels 106. Each of the four drive wheels is driven by its own compressed air motor 100. The corresponding four compressed air motors 100 are attached to a pressure tank 105. The pressure tank 105 runs longitudinally centrally in the vehicle 150.

[0150] It is explicitly stated that all indications of ranges or groups of units disclose every possible intermediate value or subset of units for the purpose of the original disclosure as well as for the purpose of limiting the claimed invention, in particular also as a limit of a range. List of reference symbols

[0151] 1 Cylinder-reciprocating piston device 5 Hollow cylinder 10 Hollow cylinder inner wall 15 Piston 20 Pressure chamber 25 Shell surface 30 Ceiling wall 35 First pressure chamber opening 36 First pressure chamber inlet opening 37 First pressure chamber outlet opening 40 Bottom wall 45 Second pressure chamber opening 46 Second pressure chamber inlet opening 47 Second pressure chamber outlet opening 50 Piston rod opening 51 Pressure sensor 52 Temperature sensor 55 First pressure chamber 56 First dead space volume 57 Second dead space volume 60 Second pressure chamber 65 Electric valve 66 Valve flow channel 67 Valve closure part 68 Minimum flow cross-section 70 Piston rod 100 Air motor 105Pressure tank 106Drive wheel OTFirst end position UTSecond end position HKiss stroke DKPiston outer diameter

Claims

1. A compressed air engine (100), comprising: at least two cylinder / reciprocating-piston devices (1), a piston rod (70), and a crankshaft (75), wherein a) the at least two cylinder / reciprocating-piston devices (1) each comprise: a hollow cylinder (5) which is closed upwardly and downwardly and has a hollow cylinder inner wall (10), a piston (15), a plurality of valves (65), which are electric valves or media-actuated valves, which are actuated pneumatically or hydraulically, or valves which are actuated mechanically via the crankshaft, wherein each valve has a valve flow channel (66) and a valve closing part (67), configured to close the valve flow channel (66), wherein the hollow cylinder inner wall (10) defines a pressure space (20) and comprises: - a surface (25) that delimits the pressure space (20) in the radial direction, - a ceiling wall (30) that upwardly delimits the pressure space (20) in the axial direction, - a floor wall (40) that downwardly delimits the pressure space (20) in the axial direction, and - a piston-rod opening (50) in at least one of the floor wall and the ceiling wall (30, 40), which is configured such that a piston rod (70) is guidable through it from the outside into the pressure space (20), the piston (15) is arranged in the pressure space (20) such that it divides the pressure space (20) into a first pressure space (55) between the piston (15) and the ceiling wall (30) and a second pressure space (60) between the piston (15) and the floor wall (40), the piston (15) is displaceable in a pressure-tight manner in the pressure space (20) in the axial direction between a first end position (OT), in which the piston (15) is located in the vicinity of or in contact with the ceiling wall (30), and a second end position (UT), in which the piston (15) is located in the vicinity of or in contact with the floor wall (40), and the hollow cylinder inner wall (10) further comprises: - at least one first pressure space opening (35), via which a first pressure medium is suppliable to and / or dischargeable from the first pressure space (55) through the valve flow channel (66) of at least one of the plurality of valves (65), and - at least one second pressure space opening (45), via which a second pressure medium is suppliable to and / or dischargeable from the second pressure space (60) through the valve flow channel (66) of at least one of the plurality of valves (65), b) the piston rod (70) is connected to each piston (15) of the at least two cylinder / reciprocating-piston devices (1) and extends movably outwards from the pistons (15) through the respective at least one piston rod opening (50) of the at least two cylinder / reciprocating-piston devices (1), c) the crankshaft (75) is couplable to the piston rod (70) such that the reciprocating movement of the piston rod (70) is converted into a rotational movement of the crankshaft (75), and d) the at least two cylinder / reciprocating-piston devices (1) are arranged on the same side with respect to the connection of the crankshaft (75) and the piston rod (70).

2. The compressed air engine (100) according to claim 1, further comprising: a pressure regulator configured to adjust the pressure of the first and / or second pressure medium supplied to the valves (65), or a pressure regulator configured to adjust the pressure of the first and / or second pressure medium supplied to the valves (65) for each of the first and second pressure spaces (55, 60).

3. The compressed air engine (100) according to claim 1 or 2, in which the plurality of valves are electric valves or media-actuated valves, which are actuated pneumatically or hydraulically, and further comprising: a rotational angle sensor for detecting the rotational position of the crankshaft (75), which enables a control of the plurality of valves (65) as a function of the rotational angle of the crankshaft (75), and a control with which the plurality of valves (65) of the cylinder-piston device (1) are controllable such that the cylinder-piston device (1) is selectively switchable between - a 1-stroke mode, wherein in every movement between the end positions the piston (15) is impinged with pressure medium, or - a multi-stroke mode, wherein in some but not all movements between the end positions the piston (15) is not impinged with pressure medium.

4. The compressed air engine (100) according to one of the preceding claims, in which the direction of rotation of the crankshaft (75) is reversible by means of the control and / or the at least two of the cylinder / reciprocating-piston devices (1) are differently designed.

5. The compressed air engine (100) according to one of the preceding claims, comprising: at least two of the cylinder / reciprocating-piston devices (1) each with a piston rod (70), which are each connected to the same crankshaft (75).

6. The compressed air engine (100) according to one of the preceding claims, in which the at least two cylinder / reciprocating-piston devices (1), and / or the piston rods (70) and / or the crank arms of the crankshaft (75), to which the piston rods (70) are connected, are configured differently such that the at least two cylinder / reciprocating-piston devices (1) have different displacements and / or different stroke heights.

7. The compressed air engine (100) according to one of the preceding claims, in which the pressure of the first and / or second pressure medium for each of the first and second pressure spaces (55, 60) of the at least two of the cylinder / reciprocating-piston devices (1) is adjustable independently of one another, in particular are switchable off independently of one another, and / or the first pressure media of the at least two of the cylinder / reciprocating-piston devices (1) are at least partially different from one another, and / or the second pressure media of the at least two of the cylinder / reciprocating-piston devices (1) are at least partially different from one another.

8. The compressed air engine (100), according to one of the preceding claims, in which: the plurality of valves (65) are electric valves or media-actuated valves, which are actuated pneumatically or hydraulically, the control controls the plurality of valves (65) of a plurality of cylinder / reciprocating-piston devices (1) such that at least two of the cylinder / reciprocating-piston devices (1) operate with different strokes times and / or with different pressure differences between the first and second pressure spaces (55, 60) in the first and second end positions and / or are switchable off independently of one another, and / or the control determines the control times of the plurality of valves (65) as a function of a load situation.

9. The compressed air engine (1) according to one of the preceding claims, in which the crankshaft (75) is connected to the piston rod (70) via a connecting rod such that the piston rod (70) is guided linearly.

10. The compressed air engine (1) according to one of the preceding claims, further comprising: a second crankshaft (75), which is configured to operate as a double crank drive together with the first crankshaft (75), in which the first crankshaft (75) and the second crankshaft (75) are configured to rotate in opposite directions at the same speed, and the piston rod (70) is connected to each of the crankshafts (75) via a connecting rod (80) such that the piston rod (70) is guided linearly and the piston (15) is moved during rotation of the double crankshaft drive by 360 degrees of crankshaft angle from the first end position into the second end position and back again into the first end position.

11. The compressed air engine (100) according to one of the preceding claims, in which at least one of the at least two cylinder / reciprocating-piston devices (1) has a first displacement, which results from the piston stroke (H) and the effective cross-sectional area of the piston (15) in relation to the first pressure space (55), and a second displacement, which results from the piston stroke (H) and the effective cross-sectional area of the piston (15) in relation to the second pressure space (60), and the valve flow channels (66) of the plurality of valves (65) are closable by means of the valve closing parts (67) such that a first dead volume (56) is formed when the piston (15) is located in the first end position (OT), which is less than 30%, preferably less than 15%, further preferably less than 5%, further preferably less than 2.5%, further preferably less than 1% of the first displacement, a second dead volume (57) is formed when the piston (15) is located in the second end position (UT), which is less than 30%, preferably less than 15%, further preferably less than 5%, further preferably less than 2.5%, further preferably less than 1% of the second displacement, wherein the first dead volume (56) is formed by the volume of the first pressure space (55) when the piston (15) is located in the first end position (OT) and a volume that is fillable with the first pressure medium and is located between the valve closing part (67) of the at least one valve (65) in the closed state, via which the first pressure medium is suppliable to and / or dischargeable from the first pressure space, and the first pressure space (55), and the second dead volume (57) is formed by the volume of the second pressure space (60) when the piston (15) is located in the second end position (UT) and a volume that is fillable with the second pressure medium and is located between the valve closing part (67) of the at least one valve (65) in the closed state, via which the second pressure medium is suppliable to and / or dischargeable from the second pressure space, and the second pressure space (55).

12. The compressed air engine (100) according to one of the preceding claims, in which, in at least one of the at least two cylinder / reciprocating-piston devices (1) the at least one first pressure space opening (35) is arranged in the ceiling wall (30) and the at least one second pressure space opening (45) is arranged in the floor wall (40).

13. The compressed air engine (100) according to one of the preceding claims, in which at least one of the at least two cylinder / reciprocating-piston devices (1) comprises: one or more inlet first pressure space openings (36), via which the first pressure medium is suppliable through the valve flow channel (66) in each case of one of the plurality of valves (65) into the first pressure space (20), and one or more outlet first pressure space openings (37), via which the first pressure medium is dischargeable through the valve flow channel (66) in each case of one of the plurality of valves (65) from the first pressure space (55), and / or one or more inlet second pressure space openings (46), via which the second pressure medium is suppliable through the valve flow channel (66) in each case of one of the plurality of valves (65) into the second pressure space (60), and one or more outlet second pressure space openings (47), via which the second pressure medium is dischargeable through the valve flow channel (66) in each case of one of the plurality of valves (65) from the second pressure space (60), wherein a separate valve is provided for each of the plurality of pressure space openings, via which the first or second pressure medium is supplied or discharged.

14. The compressed air engine (100) according to claim 13, in which the valve flow channel (66) of the plurality of valves (65) has a minimum flow cross-section (68) in the open state of the respective valve (65), the minimum flow cross-section or the sum of the minimum flow cross-sections (68) of the at least one valve (65), via which the first pressure medium is suppliable to the first pressure space, is greater than 10%, preferably greater than 20% of the effective cross-sectional area of the piston (15) in relation to the first pressure space (55), and / or the minimum flow cross-section or the sum of the minimum flow cross-sections (68) of the at least one valve (65), via which the first pressure medium is dischargeable from the first pressure space, is greater than 10%, preferably greater than 20% of the effective cross-sectional area of the piston (15) in relation to the first pressure space (55), and / or the minimum flow cross-section or the sum of the minimum flow cross-sections (68) of the at least one valve (65), via which the second pressure medium is suppliable to the second pressure space, is greater than 10%, preferably greater than 20% of the effective cross-sectional area of the piston (15) in relation to the second pressure space (55), and / or the minimum flow cross-section or the sum of the minimum flow cross-sections (68) of the at least one valve (65), via which the second pressure medium is dischargeable from the second pressure space, is greater than 10%, preferably greater than 20% of the effective cross-sectional area of the piston (15) in relation to the second pressure space (55).

15. A vehicle (150), comprising: at least one compressed air engine (100) according to one of claims 1 to 13, at least one compressed air tank (105), which is configured to store at least one pressure medium.