Patent Application
20250137372
The present invention relates to a cylinder/reciprocating-piston device for a compressed air engine, a compressed air engine having such a cylinder/reciprocating piston device, and a vehicle having such a compressed air engine.
Engines are used to convert energy and, for example, to provide propulsion for a motor vehicle. Machines that convert heat into mechanical energy are known as heat engines. Heat engines include, for example, steam engines, steam turbines, and all combustion engines. A large proportion of today's combustion engines are reciprocating engines. Reciprocating engines work with a piston that is displaceably disposed in a cylinder. In this changeable cavity thus created, a part of the energy of a gaseous or liquid working medium is extracted by combustion. The expansion of the working medium during the combustion leads to movement of the piston. The piston is connected with a crankshaft by joints and a piston rod. The linear movement of the piston is transferred (converted) into a rotational movement of the crankshaft. The piston moves back and forth inside the cylinder between two end positions. The end positions are referred to as a first dead center and a second dead center. The movement from one end position into the other end position is referred to as a stroke.
Most known conventional reciprocating engines are 2-stroke or 4-stroke reciprocating engines. In a two-stroke reciprocating engine, work is performed on the piston in every second stroke by expansion of the working medium. In a 4-stroke reciprocating engine, work is performed on the piston in every fourth stroke by expansion of the working medium. The stroke in which work is performed on the piston by expansion of the working medium is also referred to as a work- or combustion-stroke.
Since work is performed in 2-stroke and 4-stroke reciprocating engines in only one stroke, a plurality of cylinders is typically used in these engines. The crank drives in these conventional multi-stroke engines are configured such that the work strokes in the respective cylinders are offset with respect to one another. The unit made of piston(s), piston rod(s) and/or connecting rod(s), crankshaft, and the joints operably coupled therebetween is referred to as a crank drive.
In order to resolve (avoid) the disadvantages of the conventional combustion engine, most recently electric propulsion systems for vehicles have been further developed. However, these are extremely problematic with respect to the environment inter alia in manufacturing and disposal.
Against this backdrop, one non-limiting object of the present teachings is to disclose components for an improved engine, an improved engine having such components, as well as an improved vehicle having an improved engine.
In one aspect of the present teachings, components are provided for an efficiently and flexibly usable and operable compressed air engine and such a compressed air engine is also provided.
A compressed air engine according to one aspect of the present disclosure includes one or more cylinder/reciprocating-piston devices that are preferably double-acting and are fillable and emptiable via preferably electric valves. In particular, a plurality of cylinder/reciprocating-piston devices can be flexibly interconnected with one another in such a compressed air engine.
In another aspect of the present disclosure, a cylinder/reciprocating-piston device includes a hollow cylinder in which a piston can move up and down. The hollow cylinder preferably includes a cylindrical outer surface. Alternatively, the hollow cylinder can also include other, for example, rectangular or oval-shaped outer surfaces. However, the inner surface, which forms (defines) the pressure chamber of the cylinder/reciprocating-piston device, is preferably always cylindrical.
The hollow cylinder may be manufactured, for example, from cast iron, aluminum, light-metal alloys, or plastics (due to the low operating temperature). The hollow cylinder can be one-part or assembled from a plurality of parts.
The inner surface of the hollow cylinder and the outer surface of the piston are attuned to each other and/or are configured with respect to each other such the piston is movable inside the cylinder in a pressure-tight manner. The hollow-cylinder inner wall forms a pressure space that is divided by the piston into a first pressure chamber and a second pressure chamber that are separated from each other in a pressure-tight manner. When the piston moves, the volume of the first pressure chamber changes inversely to the volume of the second pressure chamber. The hollow-cylinder inner wall includes at least one first pressure-chamber opening and at least one second pressure-chamber opening. One or more pressure media can be supplied to and discharged from the first or the second pressure-chamber opening via the first pressure-chamber opening and the second pressure-chamber opening. The piston may be manufactured, for example, from aluminum, or an aluminum alloy, or plastic.
The at least one first pressure-chamber opening and the at least one pressure-chamber opening are configured such that a pressure medium (pressurized medium) can be supplied and discharged via an electric valve in the first pressure chamber or the second pressure chamber. For example, the at least one 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 include, for example, an internal thread. The internal thread can be configured such that it can form a pressure-tight connection with an external thread of an electric valve, so that pressure medium can only flow through the flow channel inside the electric valve into the first or second pressure chamber.
Electric valves preferably comprise a valve flow channel and a valve closure part. The pressure medium to be controlled with (by) the electric valve can flow through the valve flow channel. The valve flow channel is closable by the valve closure part, and the flow path for the pressure medium is thus closed off. In the opened state, the valve flow channel has a minimum flow-cross-section that preferably determines the maximum fluid flow through the valve. Provided, starting from the pressure storage up to into the pressure chamber, there is no section (no throttle) having a smaller flow-cross-section, the minimum flow-cross-section of the valve flow channel also determines the maximum fluid flow from the pressure storage up to into the pressure chamber. In the closed state of the valve, preferably no pressure medium can flow through the valve flow channel. The opened state and the closed state of the electric valve preferably relate to the completely (maximally) opened state of the electric valve and the completely (maximally) closed state of the electric valve.
Amongst electric valves in the sense of this disclosure, all components are to be subsumed that serve to shut off or control of the flow of fluids (liquids or gases), and in which the actuation is effected in a (purely) electrical manner, for example, via an electromagnet, an electric servomotor having a gear drive, a worm drive, or a linear motor. In particular, solenoid valves are to be understood as falling within the scope of the term electric valve according to the present disclosure.
Valve closure parts can be formed, for example, as a plate, a cone, a ball, a pin, or a valve piston that are capable, in cooperation with a corresponding valve seat, of sealing or a closing-off of the flow channel.
A cylinder/reciprocating-piston device according to this disclosure preferably comprises at least two electric valves that preferably comprise at least one electric valve for supplying or discharging pressure medium out of the first pressure chamber, and preferably at least one electric valve for supplying or discharging pressure medium out of the second pressure chamber. However, a single multi-port valve can also be used in alternate embodiments.
In comparison to, for example, mechanical valves, a simpler, lighter, and less friction-afflicted design of the valves together with their driving and controlling is provided by the use of electric valves. Furthermore, the degrees of freedom in the adjusting and controlling are greater.
In the sense of this disclosure, a pressure medium can subsume all fluid media that can absorb, by being compressed and stored in a pressure tank, a supplied energy. The pressure medium can preferably further be supplied to a pressure chamber (first or second) or discharged from a pressure chamber, wherein the pressure medium can again release, by expansion in the pressure chamber, at least a part of the energy supplied by (absorbed due to the) compression. When the pressure medium expands in the pressure chamber, the pressure builds up in the pressure chamber, whereby the piston is set into motion. No combustion/ignition is necessary in order to expand the pressure medium. For example, compressed air is a pressure medium in the sense of the present disclosure.
According to a further example of the present teachings, ignitable gases or gas mixtures, such as hydrogen or gasoline-air mixtures, can be used as the pressure medium. In case one or more ignitable gases or gas mixtures is/are used, the cylinder/reciprocating-piston device preferably comprises a spark plug for igniting the ignitable gas or gas mixture in the first pressure chamber or the second pressure chamber, or a spark plug in each of the first and the second pressure chamber.
Such a compressed air engine can serve as a drive engine that is, for example, simple, compact, safe, and versatilely usable. In particular, when compressed air is used as the pressure medium, a drive engine can utilize an environmentally friendly drive energy source. The operating medium air is limitlessly available and usable without overexploitation of our resources. Hazardous waste, such as, for example, in the case of today's lithium-ion batteries for electric drives, does not arise over the life cycle of the engine with the use of compressed air as the drive energy. In addition, when compressed air is used as the energy carrier in a compressed air engine, the compressed air is simply compressed without pollution. The compressed air emitted from a compressed air engine is thus pollution-free and can escape (be released) unfiltered, unaltered, and quietly into the environment. In addition, the compressed air engine is usable, for example, in sensitive regions, since no pollutants arise, and depending on the construction no oil may be necessary. Thus a compressed air engine can be advantageously used, for example, for boats, hospitals, refrigerated warehouses, airports, and railway stations, or for vehicles in urban transport. A compressed air tank is chargeable, for example, using a mains-powered on-board compressor at any outlet or at stationary compressed air stations.
By the use of/with compressed air, the compressed air engine excels owing to a CO2-neutral mode of operation with zero emissions. The compressed air engine provides a drive that is simpler in production and disposal, and more environmentally friendly.
A compressed air engine is preferably modularly configurable, and thereby flexibly adaptable to various applications. The cylinder/reciprocating-piston devices of the compressed air engine can be arbitrarily arranged in series or parallel. Furthermore, different cylinder/reciprocating-piston devices can be combined with one another. Thus the compressed air engine can be specifically adapted to one or more particular performance requirement(s) and a particular application. The cylinder/reciprocating-piston device(s) of the compressed air engine can be operated both in 1-stroke processes and in multi-stroke processes, depending on the requirement(s) or operating situation. Different, even mutually different, pressure media can be used. High torques can be realized, and the torque applied by the engine can be ideally adapted to the circumstances. For example, due to the advantageous/efficient possibility of single-stroke operation, a compressed air engine having only one cylinder/reciprocating-piston device can be equal or even superior in performance to a conventional 4 cylinder, 4-stroke engine. The production costs of such a compressed air engine are low.
Thus, a compressed air engine according to the present disclosure comprises at least one cylinder/reciprocating-piston device as described above or below. Furthermore, the compressed air engine may include a piston rod and a crankshaft. In this case, the crankshaft and the piston of the at least one cylinder/reciprocating-piston device are mechanically coupled (linked) such that a (linear) back-and-forth movement of the piston can be converted, via the piston rod, into a rotational movement of the crankshaft.
In such an embodiment, the piston rod extends through a piston-rod opening in the hollow-cylindrical inner wall of the hollow cylinder of the cylinder/reciprocating-piston device. The piston rod (the outer diameter of the piston rod) and the piston-rod opening are preferably attuned to each other such that the corresponding pressure space through which the piston rod extends is sealed with respect to the exterior in a fluid-tight manner. For example, a fluid-tight sealing can be achieved by seals/seal rings in the piston-rod opening. The piston rod can extend outward from the piston from one side through the first pressure chamber or the second pressure chamber, or alternatively the piston can also extend outward from both sides through the first pressure chamber and the second pressure chamber.
Various embodiments are conceivable for the unit, referred to as a crank drive, preferably made of a piston, a piston rod, a connecting rod, a crankshaft, and connecting joints. It is preferred that the piston rod undergoes a linear movement so that a reliable outward sealing of the pressure space of the cylinder/reciprocating-piston device can be realized. It is also possible in a compressed air engine to combine various different or identical crank drives with one another.
The cylinder/reciprocating-piston device is double-acting. For this reason the piston of the cylinder/reciprocating-piston device in a power-output operation (engine operation) can be impinged with (moved by) pressure either from one or from two opposing sides. Depending on the power requirement, the mode of operation of the one or more cylinder/reciprocating-piston devices of the compressed air engine can thus be flexibly adapted.
Furthermore, the cylinder/reciprocating-piston device can be operated in a pumping mode (recuperation mode). In the pumping mode, a pressure medium can be pressurized by the piston. In a manner corresponding to the above-described power-output operation (engine operation), pressure can be applied to a pressure medium by the piston in a one-sided or two-sided manner. In the pumping mode, the piston is driven by a drive wheel, or a crankshaft coupled with the drive wheel. For example, during movement from the first end position to the second end position, air at atmospheric pressure can be aspirated into the first pressure chamber by the piston. During the return movement of the piston from the second end position into the first end position, the electric valves of the first pressure chamber are preferably closed, so that the pressure medium is sealed in the first pressure chamber. For example, when the piston is located in the first end position at the end of the movement from the second end position, the sealed pressure medium is discharged from the first chamber and can be stored, for example, in a pressure tank.
Electric valves can be switched very quickly, variably, and precisely. Short control times are thus realizable with electric valves. Furthermore, with the aid of an electronic control system, the electric valves can be controlled precisely and independently of one another. This permits a high flexibility in the mode of operation of one or more cylinder/reciprocating-piston devices in a compressed air engine.
In an alternate design, instead of the electric valves, for example, media-actuated valves that are controlled pneumatically or hydraulically, or valves actuated mechanically via the crankshaft, can be used.
According to a further alternate example, the compressed air engine can be configured as an opposed-piston engine. In an opposed-piston engine, two pistons operate in the same hollow cylinder and share a common pressure space in the center of the hollow cylinder. Accordingly one of the two pistons is connected with a first piston rod that extends outward through the ceiling wall of the hollow cylinder. The other of the two pistons is connected with a second piston rod that extends outward through the floor wall of the hollow cylinder. A crankshaft is respectively connected with the first piston rod and the second piston rod; the crankshaft converts the back-and-forth motion of the respective piston rod into rotational movement of the crankshaft. Accordingly, in such an engine, valves are additionally provided in the side wall of the hollow cylinder such that the common pressure space can be filled and emptied.
In another aspect of the present teachings, a compressed air engine is provided, together with at least one pressure tank, in a vehicle, and these components can be advantageously arranged in the vehicle.
A vehicle according to the present teachings preferably includes one or more compressed air engines, and preferably one or more pressure tanks. The pressure tank(s) is (are) configured for storing at least one pressure medium. The pressure tanks can be fluidly connected with one another (in series or parallel or combined); or, in case mutually different pressure media are stored in or different pressures exist in the respective tanks, the pressure tanks are not fluidly connected with one another. Depending on the number of different pressure media used, more pressure tanks for different media can also be used. With the use of only one pressure medium, such as, for example, compressed air, a larger compressed air tank, or alternatively a plurality of smaller compressed air tanks, can be used. For example, to implement a recuperation (pumping) function as described above, a separate pressure tank can also be provided for separate storage of the pumped medium.
In one advantageous embodiment of a vehicle according to the present disclosure, different pressure media can also be used for identical compressed air engines. Thus, for example, a compressed air engine can initially be operated with compressed air, and as needed switched to an operation with, for example, hydrogen. For example, in a vehicle according to this disclosure a plurality of compressed air engines can also be available that are each driven with their own, mutually different pressure medium. Accordingly, for example, a vehicle according to this disclosure can include a compressed air engine that is designed for operation with compressed air, and can include a compressed air engine that is designed for operation, for example, with hydrogen. A significant range increase and flexibility of fuel availability can be realized by the combination of different pressure media in a vehicle.
By utilizing a compressed air engine according to the present disclosure, a very light, energy-efficient, and flexibly propellable vehicle can be provided. Due to the flexible mode of operation of the cylinder/reciprocating-piston device of a compressed air engine, drive-train components such as, for example, a transmission and a differential can be omitted. Vehicles having a very low weight in comparison to, for example, conventional combustion engines can thereby be realized. Due to the minimal number of drive-train components, the drive train of a vehicle is very robust and extremely low-maintenance.
In a vehicle the pressure tank, which is embodied in a torsionally rigid manner, can serve as support for the vehicle body. The compact construction of a compressed air engine according to the present disclosure allows a plurality of compressed air engines to be utilized together in the vehicle. For example, each drive wheel can have a separate compressed air engine. The individual compressed air engines can also be attached to the compressed air tank(s). The compact construction of a compressed air engine according to the present teachings, as well as the possibility of omitting axle-drive components such as a transmission and a differential, allows many engine variants to be able to be flexibly implemented, and the propulsion of the vehicle to be optimally adapted to the corresponding application of the vehicle. The vehicle is also distinguished by being very safe, because the pressure medium (media) preferably may be explosion-proof and incombustible.
In a vehicle according to this disclosure, for example, a gas pedal and/or a brake pedal can be coupled with the control system of the one or more compressed air engines such that with the aid of the gas pedal and/or of the brake pedal (via the control system), the states of the electric valves (and thus the supplying and the discharging and the stopping of the supplying of compressed air into each of the one or more cylinder/reciprocating-piston devices) can be controlled as needed (power and rotational speed).
In a vehicle having at least one compressed air engine according to the present teachings, for example, the following four operating states can be implemented, with the aid of the control system, for the states of electric valves of at least one cylinder/reciprocating-piston device in a manner depending on the position of the gas pedal, of the brake pedal, and the speed of the vehicle.
A first operating state can occur, for example, when the gas pedal and the brake pedal are not actuated and the vehicle is stationary. In the first operating state, for example, all electric valves of a cylinder/reciprocating-piston device are closed. The cylinder/reciprocating-piston device thus neither delivers power (engine mode) nor does it supply energy to a pressure medium (pumping mode). According to the first operating state the vehicle is preferably in park mode.
A second operating state can occur, for example, when the gas pedal and the brake pedal are not actuated, and the vehicle moves. In the second operating state, for example, all electric valves of at least one cylinder/reciprocating-piston device are closed. In addition, a freewheel is preferably connected/present that can decouple the crankshaft, which is coupled with the one or more cylinder/reciprocating-piston device(s), from the drive wheel, which is coupled with this crankshaft, so that when the freewheel is connected the drive wheel can rotate but the piston of the cylinder/reciprocating-piston device is preferably concurrently stationary. According to the second operating state the vehicle is preferably in free-rolling mode (freewheel mode).
A third operating state can occur, for example, when the gas pedal is not actuated, but the brake pedal is actuated (depressed) and the vehicle is moving. In the third operating state one or more of the cylinder/reciprocating-piston device(s) operate(s), for example, in the above-described recuperation mode (pumping mode). In the recuperation mode the electric valves of the one or more cylinder/reciprocating-piston device(s) are preferably switched such that a pressure medium at atmospheric pressure is first aspirated into the first or the second pressure chamber(s) by the, for example, downward movement of the piston(s) of the cylinder/reciprocating-piston device(s), then is compressed in the corresponding pressure chamber(s) by the opposite movement of the piston(s), e.g., upward movement, and then discharged from the pressure chamber(s) into the same pressure tank or different pressure tanks. The use of the recuperation mode during braking processes can be range-increasing, since a pressure medium is first pressurized by the cylinder/reciprocating-piston device(s), and the pressurized medium can subsequently be used as a pressure medium for the impinging (driving, moving) of the piston(s) of the cylinder/reciprocating-piston device(s) (engine mode).
For the recuperation mode it can be advantageous to provide a separate pressure tank for the pressure medium compressed by the cylinder/reciprocating-piston device. With the use of a separate pressure tank, for example, the first pressure space of a cylinder/reciprocating-piston device can be connected both with a first pressure tank and with a second pressure tank. Here the first pressure tank is preferably connected with the first pressure space such that the pressure medium can be supplied from the first pressure tank to the first pressure chamber via an electric valve. Furthermore, the second pressure tank is preferably connected with the first pressure chamber such that the pressure medium can be supplied from the second pressure tank to the first pressure chamber via an electric valve. The second pressure tank is, for example, a tank that is designed for storage of pressure medium compressed in the recuperation mode. The cylinder/reciprocating-piston device can be operated selectively both with the first pressure tank and with the second pressure tank. For example, a 3-way valve can be present, via which electively the pressure medium from the first pressure tank or the pressure medium from the second pressure tank can be supplied to the first pressure chamber. In addition, the second pressure tank is preferably configured such that it can receive and store a pressure medium that has been compressed in the cylinder/reciprocating-piston device(s) by the piston(s). The pressure medium stored in the second pressure tank can have (be stored at) a lower pressure than the pressure medium from the first pressure tank. The pressure medium from the second pressure tank can then, for example, be retrieved (utilized, spent) when the power requirement of the vehicle is low. Such a second pressure tank can also be present independent of the recuperation function.
A fourth operating state can occur, for example, when the gas pedal is actuated (depressed) and the brake pedal is not actuated. The vehicle can be either stationary or moving. It can thus be starting-up or accelerating. In the fourth operating state the one or more cylinder/reciprocating-piston devices is (are) filled with the pressure medium via electric valves, or the pressure medium is discharged from the cylinder/reciprocating-piston devices. In full-load operation (fully depressed gas pedal), for example, all cylinder/reciprocating-piston devices of the one or more compressed air engines of the vehicle can be switched on. In the case of low power (partially depressed gas pedal), for example, pressure medium may be supplied to less than all of the cylinder/reciprocating-piston devices or discharged from it/them. Furthermore, independent of the power requirement, 1-stroke operation or multi-stroke operation can be performed.
A vehicle according to this aspect of the present disclosure excels owing to an extremely high degree of flexibility of the arranging and designing of the pressure tank(s) and of the compressed air engine(s). Due to the flexible design of cylinder/reciprocating-piston device(s) of each compressed air engine, further components of a conventional drive train such as, for example, a transmission, a differential, etc. can be omitted.
According to a further example, an adjustment of the vehicle speed of the vehicle can be realized (achieved) by the use of a plurality of drive wheels having different diameters. According to this example, preferably a (first) compressed air engine is connected with a large drive wheel of the vehicle, and a (second) compressed air engine is connected with a smaller drive wheel of the vehicle. When high speeds are to be achieved, the (first) compressed air engine of the large drive wheel can be switched on, and the (second) compressed air engine of the smaller drive wheel can be switched off, or an additional freewheel can be connected between the (second) compressed air engine of the smaller drive wheel and the smaller drive wheel. Conversely, at low speeds only the (second) compressed air engine for the smaller drive wheel is switched on, and the (first) compressed air engine for the large drive wheel is switched off, or decoupled via a freewheel. When high speeds are to be achieved, the (first) compressed air engine of the large drive wheel can be switched on. Provided both compressed air engines rotate at the same maximum speed, a higher speed of the vehicle can be achieved by the larger diameter of the large drive wheel in comparison to the smaller drive wheel.
According to an advantageous design, the piston stroke of the cylinder/reciprocating-piston device extends from a first end position to a second end position. In this embodiment, the piston stroke of the cylinder/reciprocating-piston device is smaller than the piston outer diameter.
The piston stroke is the path (length) that the piston travels between the first end position and the second end position. The piston outer diameter is the outer diameter of the (cylindrical) piston that is adapted to (fitted in) the hollow cylinder such that the piston can move in the hollow cylinder in a pressure-tight (sealed) manner. The piston outer diameter is thus the maximum diameter of the piston.
In such a design, the cylinder/reciprocating-piston device is a short stroke device. In comparison to long stroke devices having the same displacement, i.e., cylinder/reciprocating-piston devices in which the piston stroke is greater than the piston outer diameter, in a short stroke device there is more space for larger valves in the ceiling wall or floor wall of the hollow cylinder. This allows a higher pressure-medium throughput, and thus more torque and power. A compressed air engine having such a cylinder/reciprocating-piston device can be configured to be very compact with high power.
According to the exemplary design, the cylinder/reciprocating-piston device has a first dead space volume, with the piston located in the first end position, 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 a first displacement described below. And the cylinder/reciprocating-piston device has a second dead space volume, with the piston located in the second end position, that 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 a second displacement described below.
The first displacement is determined from the piston stroke and the effective cross-sectional surface area of the piston with reference to the first pressure chamber.
The second displacement is determined from the piston stroke and the effective cross-sectional surface area of the piston with reference to the second pressure chamber.
The effective cross-sectional surface area of the piston is the surface area of the piston, facing the ceiling wall or the floor wall, that delimits the first pressure space downwardly or the second pressure space upwardly. In other words, the effective cross-sectional surface area results from a projection of the surface area of the piston facing the ceiling wall or the floor wall onto a surface perpendicular to the direction of movement of the piston. Accordingly, the area at which a piston rod is connected is not contained in the effective cross-sectional surface area. In a simplified view, the effective cross-sectional surface area therefore results from the cross-sectional surface area of the piston (including any piston rings) less the cross-sectional surface area of the possibly-present piston rod.
The term “first dead space volume” is understood to mean the volume that is located between the piston located in the first end position and the electric valves in the closed position, via which electric valves the first pressure medium is supplyable into or dischargeable from the first pressure chamber. With respect to the electric valves, the valve closure part that is in the closed state is to be used as a reference.
The first dead space volume is thus formed on the one hand by the volume of the first pressure chamber when the piston is located in (at) the first end position. On the other hand, the first dead space volume is formed by the volume, which is fillable with the pressure medium, that is formed (defined) between (delimited by) the valve closure part of the at least one electric valve in the closed state, via which the first pressure medium is supplyable into and/or dischargeable from the first pressure chamber, and the first pressure chamber. Finally the first dead space volume can also be referred to as a valve-channel volume facing the pressure chamber.
The term “second dead space volume” is understood to mean the volume that is located between the piston located in the second end position and the electric valves in the closed position, via which electric valves the second pressure medium is supplyable into or dischargeable from the second pressure chamber. With respect to the electric valves, the valve closure part that is in the closed state is to be used as a reference.
The second dead space volume is thus formed on the one hand by the volume of the second pressure chamber when the piston is located in the first end position. In addition, the second dead space volume is formed by the volume, which is fillable with the pressure medium, that is formed (defined) between (delimited by) the valve closure part of the at least one electric valve in the closed state, via which the second pressure medium is supplyable into and/or dischargeable from the first pressure chamber, and the second pressure chamber. Finally the second dead space volume can also be referred to as a valve-channel volume facing the pressure chamber.
The dead space volume thus refers to a state of the cylinder/reciprocating-piston device in which all electric valves for the inlet or the outlet of the pressure medium in the first or the second pressure chamber are closed, and the piston is located either in the first position or the second position. Such an operating state can be, for example, the state of the electric valves when the vehicle is stationary.
It has been found that, with a dead space volume that 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, the response behavior of the piston is positively influenced. Due to the small dead space volume, it is achieved that after a short time the medium introduced into the first pressure chamber or second pressure chamber applies a pressure force, which corresponds to the pressure of the pressure medium, onto the piston. Compared with larger dead space volumes, a pre-compression of the gas located in the dead space volume is not necessary.
According to another advantageous design, the at least one first pressure-chamber opening is disposed in the ceiling wall, and the at least one second pressure-chamber opening is disposed in the floor wall.
Such an arrangement of the at least one first pressure-chamber opening and the at least one second pressure-chamber opening makes it possible to bring the piston into the immediate vicinity of or abutment with the ceiling wall or the floor wall.
With such an arrangement, in particular the piston can not close off in the radial direction either the at least one first pressure-chamber opening or the at least one second pressure-chamber opening, since they are disposed in the ceiling wall or the floor wall. With openings disposed in the outer surface of the hollow-cylinder inner wall, for a reliable supplying or discharging of the pressure medium out of the pressure chamber, the piston must not completely obstruct the openings. Therefore the piston cannot be brought into the immediate vicinity of or abutment with the floor wall or the ceiling wall. Furthermore, with an arrangement of the first pressure-chamber openings and/or second pressure-chamber openings in the outer surface of the hollow-cylindrical inner wall, the degree of effectiveness of the cylinder/reciprocating-piston device is reduced when the piston obstructs the at least one first pressure-chamber opening or the at least one second pressure-chamber opening.
However, according to the present embodiment, the proportion of the dead space volume that is determined by the first pressure chamber or the second pressure chamber with the piston located in (at) an end position can be designed to be minimal.
In particular with the design of the cylinder/reciprocating-piston device as a short stroke device, there is much space in the ceiling wall or floor wall of the hollow cylinder for electric valves. Depending on the particular application, it can be advantageous to control the supplying and the discharging of pressure medium into or out of the pressure chamber with a small number of large electric valves, or with a large number of small electric valves. Smaller electric valves excel, for example, owing to very short switching times. On the other hand, larger valves can achieve, for example, a higher volume flow through the valve.
In accordance with another advantageous embodiment, a separate electric valve is preferably associated with each of a plurality of pressure-chamber openings (for the first and the second pressure chamber, and for the supplying and the discharging of pressure medium). The number of electric valves thus corresponds to the sum of all pressure-chamber openings for the supplying and discharging of pressure medium in the first and in the second pressure chamber. Due to such an arrangement or association of electric valves, the electric valves can be disposed very closely on the first pressure chamber or the second pressure chamber, since each pressure-chamber opening includes a separate electric valve for supplying or discharging pressure medium. Accordingly a very small dead space volume can be realized. Furthermore, due to such an association, the inlet or the outlet of the pressure medium in the first or in the second pressure chamber can be controlled separately from one another. A maximum degree of flexibility, and thus high adaptability of the engine to any operating state or a particular load situation and/or power requirement in the particular operating situation, thereby results.
According to another exemplary embodiment, electric valves having a relatively large minimum flow-cross-section in comparison to effective cross-sectional surface areas of the piston are used. The throughput of pressure medium that is supplied to the pressure chamber or discharged from the pressure chamber can thereby be very high, and thus a high performance of the engine can be achieved. The cross-sectional surface areas of the other 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 preferably 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 other flow paths between the pressure tank and the cylinder/reciprocating-piston device.
In a power-output mode (engine mode), the pressure medium that is discharged from the first pressure chamber or the second pressure chamber is preferably less strongly compressed than the pressure medium that enters into the first pressure chamber or into the second pressure chamber. In order, for example, to match the flow speeds of inflowing and outflowing pressure media to each other, according to another exemplary embodiment, the sum of the minimum flow-cross-sections of the electric valves that are responsible for the exhaust of the pressure medium are preferably enlarged in relation to the electric valves that are responsible for the intake of pressure medium.
According to another exemplary design of the present disclosure, the cylinder/reciprocating-piston device includes at least two inlet first-pressure-chamber openings and at least two outlet first-pressure-chamber openings. Additionally or alternatively, the cylinder/reciprocating-piston device includes at least two inlet second-pressure-chamber openings and at least two outlet second-pressure-chamber openings.
The at least two first-pressure-chamber openings (inlet and outlet) and the at least two second-pressure-chamber openings (inlet and outlet) are preferably arranged symmetrically with respect to the axis of rotation of the pressure space. Due to the use of a plurality of first- or second-pressure-chamber openings, the amount of pressure medium supplied to the pressure space can be increased. If, according to one exemplary embodiment, each opening of the first- or second-pressure-chamber openings has a separate electric valve, then in addition all or only some of the openings can be opened with the aid of the control system and an individual controlling of the electric valves. Thus with the aid of the control system, the amount of pressure medium supplied to the pressure chamber is flexibly adaptable.
According to another exemplary embodiment of the present disclosure, the cylinder/reciprocating-piston device preferably includes a pressure sensor for measuring a pressure, and/or a temperature sensor for measuring of 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 chambers.
According to another exemplary design of the present disclosure, a compressed air engine may further include at least one pressure regulator. A pressure regulator is preferably disposed (fluidly connected) between the respective pressure tank in which the respective pressure medium for the respective cylinder/reciprocating-piston device is located, and the corresponding cylinder/reciprocating-piston device. In order to, for example, reduce a high pressure in a pressure tank to a lower pressure for supplying the pressure (pressurized) medium, for example, a plurality of pressure regulators in the form of reducer valves can be provided as pressure-reducing stages. Optionally, additional intermediate pressure tanks may also be provided. According to this embodiment it is possible, for example, to increase or reduce, with the aid of the pressure regulator(s), the pressure of the pressure medium that flows out of the pressure tank to the pressure regulator(s), and then to supply the pressure medium at a reduced pressure to the cylinder/reciprocating-piston device. The pressure of the pressure medium influences the power output of the cylinder/reciprocating-piston device(s), since with higher pressure more force can be exerted onto the piston(s) of the cylinder/reciprocating-piston device(s). The (each) pressure regulator preferably includes different output lines (output flow paths), in which the pressure of the pressure medium can differ. Thus with one pressure regulator, multiple cylinder/reciprocating-piston devices can be supplied with a pressure medium with different pressures regulated by the pressure regulator. According to this embodiment, a very high degree of flexibility is provided for the mode of operation of the individual cylinder/reciprocating-piston devices. With the aid of the pressure regulator(s) in a compressed air engine having a plurality of cylinder/reciprocating-piston devices, the pressure can preferably be individually adjusted in each of the first pressure chambers and the second pressure chambers.
According to another exemplary design of the present disclosure, the compressed air engine may include a rotational-angle sensor for the detecting of the rotational position of the crankshaft.
Such a compressed air engine may further include a control system. The control system is preferably an electronic control system. With the control system, the plurality of electric valves of the cylinder/reciprocating-piston device are, for example, controllable such that, as needed, the cylinder/reciprocating-piston device is selectively switchable between operating in a 1-stroke mode, in which the piston is impinged with pressure with each movement between the end positions, or operating in a multi-stroke mode, in which in individual movements between the end positions the piston is not impinged with pressure.
The control system is configured to control, i.e., to open and to close, the electric valves of the one or more cylinder/reciprocating-piston devices. A signal from the one or more rotational angle sensors, which determine the rotational position of the one or more crankshafts and can transmit this value to the control system, preferably serves as input value for the control system. With the aid of this input value, the control system can determine in which position the pistons which are connected with the corresponding crankshaft, on which the rotational angle sensor is located, are located.
For example, the control system can be designed such that a rotational angle of the crankshaft of 0° or 360° corresponds to a position of the piston in the first end position, and a rotational angle of 180° corresponds to a position of the piston in the second end position.
In the following, by way of example the control system of the electric valves is described for the case that the electric valves are opened and closed precisely when the piston is located in the first end position or in the second end position. Alternatively, the opening/closing can occur at any other points in time, depending on the load situation.
In (at) the first end position of the piston, the volume of the first pressure chamber is minimal and the volume of the second pressure chamber is maximal. With the aid of the rotational angle sensor of the crankshaft, the control system recognizes that the piston is located in (at) the first end position, and opens the electric valve via which the first pressure (pressurized) medium is supplyable into the first pressure chamber, and closes the electric valve via which the first pressure medium is dischargeable out of the first pressure chamber. Furthermore, the control system opens the electric valve via which the second pressure medium is dischargeable out of the second pressure chamber, and closes the electric valve via which the second pressure medium is supplyable into the second pressure chamber. In accordance with these states of the electric valves, the first pressure medium is supplied to the first pressure chamber, the first pressure medium builds up a pressure in the first pressure chamber, and thus presses the piston away from the first end position toward the second end position of the piston. The piston then reaches the second end position.
In (at) the second end position, the volume of the second pressure chamber is minimal and the volume of the first pressure chamber is maximal. With the aid of the rotational angle sensor of the crankshaft, the control system recognizes that the piston is located in (at) the second end position, and, when the piston is located in the second end position, opens the electric valve via which the second pressure medium is supplyable into the second pressure chamber, and closes the electric valve via which the second pressure medium is dischargeable out of the second pressure chamber. Furthermore, the control system opens the electric valve via which the first pressure medium is dischargeable out of the first pressure chamber, and closes the electric valve via which the first pressure medium is supplyable into the first pressure chamber.
However, the electric valves can preferably also be opened and closed by the control system in a manner deviating from the manner outlined above in which the opening and closing of the electric valves takes place precisely at a crank angle of 0°/180°/360° or precisely in (at) a first end position or in (at) a second end position.
For example, when the piston moves from the second end position to the first end position, the electric valve via which the first pressure medium is supplyable into the first pressure chamber is already opened, and the electric valve via which the first pressure medium is dischargeable out of the first pressure chamber is already closed before the piston reaches the first end position, preferably at a rotational angle of the crankshaft of 330°-359°, further preferably of 345°-355°. A crankshaft rotational angle of 0°/360° corresponds in this example to the position of the piston in (at) the first end position. A crankshaft rotational angle of 180° corresponds in this example to the position of the piston in (at) the second end position. In addition, the electric valve via which the second pressure medium is supplyable into the second pressure chamber is already closed, and the electric valve via which the second pressure medium is dischargeable from the second pressure chamber is already open, before the piston reaches the first end position, preferably at 330°-359°, further preferably at 345°-355°.
Due to the inertia of the entire crank drive, of which the piston is a part, the piston preferably moves (immediately after the above-described manner of the opening and closing of the electric valves) to the first end position (360° crankshaft rotational angle). When the piston is then located in (at) the first end position, a higher pressure acts directly on the piston, which pressure presses it back to its second end position, compared with the case in which the electric valves open or close at 360°.
Corresponding to control times described above by way of example for the first end position, the control times are preferably also adapted for the second end position. For the second end position, accordingly a control time point results for the opening or closing the electric valves at 150°-179°, further preferably at 165°-175°. This control time point falls 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 point, the electric valve via which the second pressure medium is supplyable into the second pressure chamber, and the electric valve via which the first pressure medium is dischargeable out of the first pressure chamber, are opened. In addition, the electric valve via which the second pressure medium is dischargeable out of the second pressure chamber, and the electric valve via which the first pressure medium is supplyable into the first pressure chamber, are closed.
The control system is preferably supplied with voltage via an energy source of the vehicle. With a plurality of cylinder/reciprocating-piston devices, the control system can be in control-connection with each individual one of the plurality of cylinder/reciprocating-piston devices such that each individual one of the electric valves of the plurality of cylinder/reciprocating-piston devices can open and close independently of one another. In this way a very broad usage spectrum and high flexibility of the compressed air engine can be realized.
According to a further exemplary embodiment of the control system, the control times can be set variably such that the time points for the opening and the closing of the electric valves differ from one another in order to realize the least consumption with the best performance. In particular, the control times can be variably changed or set during the operation.
Thus, for example, based on the first end position, and with a piston moving from the second end position into the first end position, the electric valve via which the pressure medium is supplyable into the first pressure chamber can be opened at a 330°-359° crankshaft rotational angle, further preferably at 345°-355°, and the electric valve via which the pressure medium is dischargeable out of the first pressure chamber is then closed, displaced by a crankshaft rotational angle in the range of a 0.11° to 10°, preferably a 1° to 7° crankshaft rotational angle. For example, the electric valve via which the pressure medium is supplyable into the first pressure chamber could thus be opened at a 355° crankshaft rotational angle, and the electric valve via which the pressure medium is dischargeable out of the first pressure chamber, for example, then offset by a 1° crankshaft rotational angle, i.e., closed at a 356° crankshaft rotational angle.
Of course, the same applies in a corresponding manner with respect to the electric valves of the second pressure chamber with reference to the second end position.
A cylinder/reciprocating-piston device can be operated with the control system in a 1-stroke mode or a multi-stroke mode.
In a 1-stroke mode, the piston is impinged with pressure with each movement between the first end position and the second end position. In other words, a pressure (pressurized) medium is always alternatingly supplied to the first pressure chamber in order to press the piston toward the second end position, and a pressure medium is supplied into the second pressure chamber in order to press the piston from the second end position back to the first end position.
In contrast, in a multi-stroke mode the piston is not impinged with pressure with each stroke. For example, in a cylinder/reciprocating-piston device the electric valve via which the second pressure medium is discharged out of the second pressure chamber is always open, so that atmospheric pressure prevails in the second pressure chamber. In a corresponding manner, also no pressure medium is supplied to the second pressure chamber. For example, whenever the piston is located in (or near) the first end position, pressure medium is supplied to the first pressure chamber. The supplying of the pressure medium into the first pressure chamber is thus effected with every second stroke movement of the piston. Correspondingly this example is a multi-stroke mode, namely a 2-stroke mode of the cylinder/reciprocating-piston device.
In another advantageous design according to the present disclosure, the direction of rotation of the crankshaft is reversible with the aid of the control system.
When the vehicle is stationary, the control system preferably recognizes in (at) which position (crankshaft rotational angle) the crankshaft is located. The control system can selectively control the electric valves such that either pressure medium is first supplied into the first pressure chamber, or pressure medium is first supplied into the second pressure chamber. Depending on the pressure chamber selected, the piston can be moved up or down starting from the stationary position. Depending on whether the piston is moved upward or downward, the crankshaft rotates clockwise or counterclockwise. This corresponds to a forward or reverse movement of the vehicle.
In another exemplary design according to the present disclosure, at least two of the cylinder/reciprocating-piston devices have a common piston rod that is connected to each of the pistons of the cylinder/reciprocating-piston devices.
According to this embodiment, multiple cylinder/reciprocating-piston devices are connected to one another in series. In other words, the pistons of the at least two cylinder/reciprocating-piston devices are connected with 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 correspondingly identical. In contrast, the displacements can differ, for example, due to different outer diameters of the respective pistons of the at least two cylinder/reciprocating-piston devices. Correspondingly, for example, the pistons of the at least two cylinder/reciprocating-piston devices press the piston rod upward or downward together. The piston rod is connected with a crankshaft.
The at least two of the cylinder/reciprocating-piston devices can be identical, or differ, for example, with respect to the effective cross-sectional surface area of the pistons. The at least two cylinder/reciprocating-piston devices can be disposed on the same side or on opposite sides with respect to the connection of crankshaft and piston rod. The compressed air engine can thereby be flexibly adapted to the particular space requirements.
According to another advantageous design of the present disclosure, the compressed air engine includes at least two cylinder/reciprocating-piston devices, each having one piston rod. The piston rods are each connected with the same crankshaft. According to this embodiment, a plurality of cylinder/reciprocating-piston devices are thus connected with one another in parallel.
In contrast to the above-mentioned series connection of cylinder/reciprocating-piston devices in which the stroke height is always identical, with cylinder/reciprocating-piston devices connected in parallel the stroke heights can be different. Greater stroke heights thereby enable, for example, the crank arms of the common crankshaft, with which the respective piston rod is connected, to be made longer, and thus the connection between piston rod and crank arm can be made to 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 crank arm correspondingly results in a longer 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.
For example, compressed air engines according to the present disclosure can be constructed, e.g., as a radial engine, a boxer engine, an opposed-piston engine, a V engine, etc. In the case of a radial engine, the cylinder/reciprocating-piston devices are arranged, for example, radially around the crankshaft.
In another exemplary design of the present teachings, the at least two cylinder/reciprocating-piston devices, and/or the piston rods, and/or the crank arms of the crankshaft with which the piston rods are connected, are constructed differently. Thus the at least two cylinder/reciprocating-piston devices can be provided with different displacements and/or different stroke heights.
With cylinder/reciprocating-piston devices connected in series, for example, the effective cross-sectional surface areas (in particular the piston outer diameters) can differ.
With cylinder/reciprocating-piston devices connected in parallel, the stroke heights, for example, can differ by different-length crank arms of the common crankshaft, at the end of which crank arms the piston rod is connected with the crankshaft.
According to this embodiment it is possible to flexibly design the cylinder/reciprocating-piston devices of a compressed air engine, and adapt the cylinder/reciprocating-piston devices to one another, such that a compressed air engine optimally tailored to the particular application case can be provided. The various cylinder/reciprocating-piston devices can be different and connectable independently of one another.
In another exemplary design according to the present disclosure, the pressure of the first and/or second pressure (pressurized) medium of each first and second pressure chambers of the at least two of the cylinder/reciprocating-piston devices is adjustable independently of each other. In particular, the at least two of the cylinder/reciprocating-piston devices can be switched off independently of one another. Furthermore, they are preferably also fillable with different media and/or different pressures.
For example, the pressure of each pressure chamber can be set with the aid of a pressure regulator that is located between the first or the second pressure chamber and the pressure tank. For example, with such an embodiment the cylinder/reciprocating-piston device can be selectively operated in a multi-stroke mode only with the first pressure medium, or operated only with the second pressure medium. In addition, a cylinder/reciprocating-piston device can be selectively switched off. The term “switched off” means, for example, that the electric valves of the corresponding cylinder/reciprocating-piston device remain closed, and no pressure medium is supplied to the cylinder/reciprocating-piston device.
In another exemplary design according to the present disclosure, the first pressure media of the at least two of the cylinder/reciprocating-piston devices are, at least in part, different from each other. For example, the cylinder/reciprocating-piston devices can be connected with different pressure tanks, or can be connected with different regions of a pressure tank. Additionally or alternatively, the second pressure media of the at least two of the cylinder/reciprocating-piston devices are, at least in part, different from each other.
Such an embodiment offers high flexibility of the pressure media used, which can be exchanged depending on availability or intended purpose.
According to another exemplary design of the present teachings, the control system controls the plurality of electric valves of the plurality of cylinder/reciprocating-piston devices such that at least two of the cylinder/reciprocating-piston devices operate with different stroke times and/or operate with different pressure differences between the first and second pressure chamber in the first and second end position, and/or can be switched off independently of one another.
According to another exemplary design of the present teachings, the control system determines the control times of the plurality of electric valves in a manner that is dependent on the load situation. The load situation results, for example, from the load requirement (gas pedal), pressure, and rotational speed.
Control times are the points in time in (at) which the valve closure parts unblock the valve flow channels of the electric valves for the supplying or the discharging of the first or second pressure medium into/out of the first or second pressure chamber. Adjustment of the control times allows an efficiency increase of the engine, depending on the particular load behavior. This increase can come about as a power- and torque-gain and as fuel savings.
In another exemplary design according to the present disclosure, the piston rod is connected with the crankshaft via a connecting rod such that the piston rod is linearly guided. According to this embodiment, it is ensured that the pressure space can be reliably sealed outwardly. A reliable sealing is possible due to a purely linear back-and-forth movement of the piston rod. Any possible crank drive that realizes a linear back-and-forth movement of the piston rod can preferably be used.
According to another exemplary design, in a vehicle according to the present disclosure the at least one pressure tank serves as a support of the vehicle body and/or of the chassis. The at least one pressure tank can be formed integrally by supporting body components and/or as a centrally extending pillar.
A very compact and rigid construction can be achieved by such a design of the vehicle. The pressure tank serves on the one hand to store the pressure medium, and also simultaneously serves as support for the vehicle body. Alternatively, the pressure tank can also be formed integrally by body components. A large pressure tank can be disposed for this purpose, for example, centrally in the longitudinal direction of the vehicle. Alternatively or additionally, for example, a plurality of smaller pressure tanks can also be arranged.
Furthermore, one or more pressure tanks can be carried along in a trailer or the like.
A plurality of compressed air engines can be used in a vehicle. The plurality of compressed air engines can be disposed at different locations in the vehicle. A plurality can also be disposed in a common housing.
According to further exemplary design of the present disclosure, the vehicle includes a freewheel. The power flow between a compressed air engine and a drive wheel is interruptible by the freewheel, so that the compressed air engine can be switched off during the travel of the vehicle.
The freewheel can be configured such that is switchable in both a forward movement of the vehicle and a reverse movement of the vehicle, and the freewheel correspondingly allows the switching-off of the compressed air engine both during forward movement and during reverse movement of the vehicle. The freewheel can additionally be equipped with a gear transmission or gear reduction that are optionally also switchable.
Exemplary embodiments of the invention are explained in the following based on the Figures.
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.
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.
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.
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
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
The state shown in
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.
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
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.
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
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
The state shown in
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
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
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
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.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2021 121 317.7 | Aug 2021 | DE | national |
This application is the US national stage of International Patent Application No. PCT/EP2022/071063 filed on Jul. 27, 2022, which claims priority to German Patent Application No. 10 2021 121 317.7 filed on Aug. 17, 2021.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/071063 | 7/27/2022 | WO |
