WO2000037800A1 - Device for converting energy being stored in compressed air into mechanical work - Google Patents

Device for converting energy being stored in compressed air into mechanical work Download PDF

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Publication number
WO2000037800A1
WO2000037800A1 PCT/AT1999/000307 AT9900307W WO0037800A1 WO 2000037800 A1 WO2000037800 A1 WO 2000037800A1 AT 9900307 W AT9900307 W AT 9900307W WO 0037800 A1 WO0037800 A1 WO 0037800A1
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WO
WIPO (PCT)
Prior art keywords
hydraulic
pressure
compressed air
pneumatic
cylinder units
Prior art date
Application number
PCT/AT1999/000307
Other languages
German (de)
French (fr)
Inventor
Jörg THURNER
Original Assignee
Tcg Unitech Aktiengesellschaft
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tcg Unitech Aktiengesellschaft filed Critical Tcg Unitech Aktiengesellschaft
Priority to JP2000589832A priority Critical patent/JP2002533609A/en
Priority to BR9916452-3A priority patent/BR9916452A/en
Priority to EP99963158A priority patent/EP1141549A1/en
Priority to AU19581/00A priority patent/AU1958100A/en
Publication of WO2000037800A1 publication Critical patent/WO2000037800A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/06—Servomotor systems without provision for follow-up action; Circuits therefor involving features specific to the use of a compressible medium, e.g. air, steam
    • F15B11/072—Combined pneumatic-hydraulic systems
    • F15B11/0725—Combined pneumatic-hydraulic systems with the driving energy being derived from a pneumatic system, a subsequent hydraulic system displacing or controlling the output element
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/007—Installations or systems with two or more pumps or pump cylinders, wherein the flow-path through the stages can be changed, e.g. from series to parallel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B9/00—Piston machines or pumps characterised by the driving or driven means to or from their working members
    • F04B9/08—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid
    • F04B9/12—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being elastic, e.g. steam or air
    • F04B9/129—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being elastic, e.g. steam or air having plural pumping chambers
    • F04B9/1295—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being elastic, e.g. steam or air having plural pumping chambers having two or more pumping chambers in series
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
    • F15B1/02—Installations or systems with accumulators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20569—Type of pump capable of working as pump and motor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/21—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge
    • F15B2211/216—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge the pressure sources being pneumatic-to-hydraulic converters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30505—Non-return valves, i.e. check valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/3056—Assemblies of multiple valves
    • F15B2211/30565—Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve
    • F15B2211/30575—Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve in a Wheatstone Bridge arrangement (also half bridges)
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/327—Directional control characterised by the type of actuation electrically or electronically
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
    • F15B2211/50518—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using pressure relief valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5151—Pressure control characterised by the connections of the pressure control means in the circuit being connected to a pressure source and a directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5153—Pressure control characterised by the connections of the pressure control means in the circuit being connected to an output member and a directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5156—Pressure control characterised by the connections of the pressure control means in the circuit being connected to a return line and a directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/55—Pressure control for limiting a pressure up to a maximum pressure, e.g. by using a pressure relief valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6306—Electronic controllers using input signals representing a pressure
    • F15B2211/6309—Electronic controllers using input signals representing a pressure the pressure being a pressure source supply pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6336—Electronic controllers using input signals representing a state of the output member, e.g. position, speed or acceleration
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7058—Rotary output members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
    • F15B2211/7135—Combinations of output members of different types, e.g. single-acting cylinders with rotary motors

Definitions

  • the present invention relates to a device for converting energy stored in compressed air into mechanical work, which has the following components:
  • At least one compressed air tank for storing compressed air
  • a plurality of cylinder units each with at least one pneumatic work space for relaxing the compressed air and with at least one hydraulic work space for conveying a hydraulic medium, the pneumatic work space and the hydraulic work space each having a piston which are coupled to one another;
  • a high-pressure hydraulic line which is connected to the hydraulic work spaces of the cylinder units and which is designed to transport a high-pressure hydraulic medium
  • a hydraulic drive connected to the high-pressure hydraulic line, which is preferably designed as a hydraulic motor, and which is driven by the high-pressure hydraulic medium.
  • compressed air as a storage medium for energy offers a number of advantages.
  • mobile applications for example in motor vehicles, it is of particular importance that compressed air containers which are of lightweight construction can achieve higher energy densities than is possible with batteries.
  • compressed air tanks are far superior to batteries in terms of cost and service life.
  • the direct conversion of the energy stored in compressed air into mechanical work is not possible or not advantageous for a number of applications.
  • Systems have therefore been proposed in which the energy contained in the compressed air is first introduced into a hydraulic system and is subsequently converted into mechanical work by a hydraulic motor.
  • the advantages of such a solution are that hydraulic systems are very well developed and developed and hydraulic motors are small, compact, inexpensive and easily available for a variety of different areas of application.
  • the present invention can also be used in connection with hydraulic cylinders as a hydraulic drive.
  • a piston machine is known from WO 97/17546 with which the conversion of the pneumatic energy into hydraulic energy can be carried out.
  • the compressed air is in operation the device at very different pressures. This is due on the one hand to the fact that the pressure in a pressure vessel drops continuously as a result of the removal, and on the other hand pressure fluctuations occur during the working stroke of a piston machine. In the hydraulic circuit, however, largely constant pressure is desired, which cannot be easily achieved by a buffer store alone.
  • WO 98/17492 proposes a drive system for a motor vehicle in which a pressure multiplier, which is controlled in stages, is connected downstream of a pneumohydraulic converter in order to compensate the fluctuating hydraulic pressure as far as possible.
  • connection of a separate device to compensate for pressure fluctuations is complex and it is difficult to integrate the required assemblies into a motor vehicle.
  • the object of the present invention is to avoid these disadvantages and to develop a device of the type described above in such a way that a high degree of efficiency is achieved with the least possible outlay.
  • At least one changeover valve is provided which connects the hydraulic work space of a cylinder unit either with the hydraulic high pressure line or with the hydraulic work space of another cylinder unit.
  • the basic idea of the present invention is that several independent, but basically identical cylinder units are provided, which are connected differently depending on the current pressure conditions. If there is a high pressure in the pneumatic work space of a cylinder unit, the corresponding hydraulic work space can be connected directly to the hydraulic high-pressure line. However, if the pressure drops below a predetermined limit value, switching control valves causes another cylinder unit to be supported with the now lower hydraulic pressure so that it can generate the required hydraulic pressure.
  • the pressure drop described can be caused on the one hand by the fact that the pneumatic pressure drops due to the progressive consumption of compressed air or on the other hand by the course of the expansion movement, during which the pressure also drops.
  • all existing cylinder units can be connected in series to build up the required hydraulic pressure. If, for example, the piston surfaces of the pneumatic part are in a ratio of 3: 1 to the piston surfaces of the hydraulic part for all cylinder units, a total transmission ratio between 3: 1 and 18: 1 can be achieved with six cylinder units. If cylinder units with different gear ratios are available, the overall gear ratio can be varied within an even wider range.
  • a particularly compact design of the device according to the invention is possible in that the cylinder units have double-action, each with two pneumatic work spaces and two hydraulic work spaces are formed, which are separated from each other by a one-piece piston.
  • the hydraulic medium from the hydraulic work space of a cylinder unit is connected to the latter when the pressure is greater than the nominal pressure of the hydraulic high-pressure line. If the pressure drops, the changeover valve switches over, and the hydraulic working space of this cylinder unit is connected to the hydraulic working space of another cylinder unit, namely the one from which the piston moves. This means that the piston is not only moved pneumatically but also hydraulically in order to be able to generate a higher pressure.
  • Optimal operation of the device is achieved when all valves u. Like. Be controlled electronically. In order to be able to optimally carry out such a control, it is particularly advantageous if, in addition to corresponding pressure transducers, displacement transducers are also provided which detect the respective position of the pistons.
  • the pneumatic working spaces of the cylinder units are connected via switching valves to a common low-pressure pneumatic line which is designed for a pressure level in a range between 5 and 15 bar.
  • a common low-pressure pneumatic line which is designed for a pressure level in a range between 5 and 15 bar.
  • This residual pressure can preferably be used in a relaxation device to drive auxiliary units such as the alternator, a pump for a power steering unit or a brake booster.
  • a conventional small turbine or a vane motor can be used as the relaxation device.
  • the efficiency of the device in relation to the energy stored in the compressed air can be increased by providing a device for heating the compressed air in the compressed air container or in a pneumatic high-pressure line, which connects the compressed air container to the pneumatic work spaces of the cylinder units.
  • a device for heating the compressed air in the compressed air container or in a pneumatic high-pressure line which connects the compressed air container to the pneumatic work spaces of the cylinder units.
  • natural energy sources such as. B. body parts heated by solar radiation
  • the waste heat from other units or a specially designed heater or both can be used.
  • waste heat By using waste heat to heat the compressed air, a theoretical system efficiency of over 100% can be achieved.
  • the hydraulic medium is heated in a simple manner in order to supply energy to the system.
  • the cylinder units are equipped with heat exchangers for introducing heat during the expansion of the compressed air. Due to the favorable design of the machine, a relatively slow operation is possible. As a result, a certain amount of heat can be supplied to the compressed air via the cylinder wall during the working strokes become.
  • the heat transfer can be further improved and the efficiency increased.
  • a pressure support line designed in the form of a closed loop is particularly preferably provided, which is connected to the hydraulic work spaces of all cylinder units via the changeover valves and which is composed of the individual supply lines .
  • a hydraulic high-pressure accumulator is provided which is connected to the hydraulic high-pressure line.
  • the hydraulic high-pressure accumulator is essential to achieve a quick response when accelerating or starting.
  • an electronic control device for the changeover valves is also provided, which is designed to switch a changeover valve of the hydraulic workspace of a first cylinder unit for connection to the hydraulic workspace of a further cylinder unit when the pressure in the hydraulic workspace of the first cylinder unit is not higher than the pressure required in the high pressure hydraulic line.
  • Fig. 1 shows a circuit diagram of an embodiment of the present invention
  • Fig. 2 shows a detail of Fig. 1 on an enlarged scale.
  • the device according to the invention consists of three compressed air containers 1 for storing compressed air up to a nominal pressure of 300 bar.
  • these compressed air tanks 1 are made of fiber-reinforced plastic in a lightweight construction.
  • the compressed air tanks 1 are connected to the cylinder units 5 a, 5b, 5 c, 5d, 5e and 5f via a pneumatic high-pressure line 2, in which a shut-off device 3 and a filter 4 are arranged.
  • the detailed circuitry of the first cylinder unit 5a is shown in FIG. 2 on an enlarged scale.
  • the remaining cylinder units 5b to 5f are of the same design.
  • the pneumatic high-pressure line 2 leads to control valves 6, 7, 8, 9 connected in opposite directions, which optionally connect the pneumatic high-pressure line 2 to a first pneumatic work space 10 or to a second pneumatic work space 11.
  • the other pneumatic work space 10, 11 is connected via the control valves 6 to 9 with a pneumatic Low pressure line 12 connected.
  • the valves 6 to 9 are each controlled so that the position of the valves 6 and 9 is the same and the position of the valves 7 and 8 is opposite to that of the valves 6 and 9. Due to the different pressure conditions in the pneumatic work spaces 10 and 11, the piston 13 of the cylinder unit 5a is moved back and forth. As a result of this movement, hydraulic oil, which is located in hydraulic workrooms 14 and 15, is guided to a further switching valve 16.
  • a safety valve 17 limits the pressure to the maximum permissible pressure.
  • the additional switching valve 16 connects one of the hydraulic working spaces 14, 15 to a hydraulic supply line 18, while the other is connected to a hydraulic supply line 19.
  • a pressure sensor 20 monitors the pressure in the hydraulic supply line 19.
  • a changeover valve 21 connects the hydraulic supply line 19 either to a hydraulic high-pressure line 22 or to the supply line 18d of the cylinder unit 5d. In the first case, the supply line 18d is simultaneously connected to a hydraulic low-pressure line 23.
  • a connecting line 39 with a check valve 38 serves to keep the high-pressure system filled even when the device is at a standstill.
  • Position sensors 24 are provided to detect the position of each piston 13. In the embodiment variant shown, three position sensors 24 detect the end positions of the piston 13 and a middle position. Together with the pressure sensors 20, it is thus possible to have the necessary information about the state of the system at all times. In particular, the detection of the central position of the pistons 23 is important, since at this point there should be approximately twice the pressure in the pneumatic working space of the respective cylinder unit as in the pneumatic low-pressure line 12. Any deviations will become apparent during the next working stroke due to a change in the control times of the valves 6, 7 , 8, 9 are taken into account.
  • the individual supply lines 18a to 18f are connected via the switching valves 16 and 21 to form a closed pressure support line, which supply the individual cylinder units 5a to 5f.
  • the common hydraulic high-pressure line 22 is connected to a hydraulic motor 26 via a control valve 24 and an adjusting valve 25.
  • a corresponding adjustment device is identified by 27.
  • a hydraulic high-pressure accumulator 28 is provided, which is connected to the hydraulic high-pressure line 22 via a control valve 29 and two pressure-limiting valves 30, 31.
  • the hydraulic low-pressure line 23 is supplied with hydraulic medium by a low-pressure tank 32 via a filter 33.
  • a pressure sensor 34 monitors the pressure in the low pressure system.
  • the low-pressure container 32 is shown as an independent component. However, this container 32 can be designed such that all the cylinder units 5a, 5b, 5c, 5d, 5e, 5f and the associated valves 6, 7, 8, 9, 16 and 21 are arranged in the oil bath within the low-pressure container 32. In this way, the installation space can be optimally used and the heat transfer on the cylinder walls can be improved.
  • a pressure which is in a range between 5 and 15 bar is maintained in the pneumatic low-pressure line 12.
  • the air of the pneumatic low-pressure line 12 is expanded to a low pressure in the area of the ambient air pressure by means of a vane-type motor 35 and is discharged to the outside via a silencer 36.
  • the vane motor 35 only drives auxiliary units 37a, 37b, 37c and 37d, which are shown schematically.
  • This auxiliary unit is an alternator, servo pumps for steering assistance or a brake booster, the compressor of an air conditioning system or the like the hydraulic low pressure line 23 and the output side is connected to the hydraulic high pressure line 22.
  • This hydraulic high-pressure pump enables loss-free control of the speed of the vane motor to be achieved in a particularly simple manner.
  • the hydraulic pump 37c uses the power available to feed oil into the high-pressure system. In this way, the consumption of compressed air can be reduced, which increases the range of a corresponding vehicle.
  • a hydraulic pressure is built up in the hydraulic working space 15 in accordance with the ratio of the effective piston areas.
  • the valve is switched so that the hydraulic delivery line 19 is connected to the hydraulic high-pressure line 22.
  • the control valve 21 is switched over. In this way, the hydraulic work space 15 is connected to the hydraulic supply line 18d for the next cylinder unit 5d.
  • valves 6, 7, 8, 9 are kept open for a correspondingly longer time in order to ultimately achieve the corresponding pressure in the pneumatic low-pressure line 12.
  • the problem of loss of efficiency due to the cooling of the compressed air during relaxation also diminishes.
  • FIGS. 1 and 2 The embodiment variant shown in FIGS. 1 and 2 is based on a one-stage expansion of the compressed air from the pressure of the pneumatic high-pressure line 2 to the pressure of the pneumatic low-pressure line 12.
  • a pneumatic medium pressure system to enable multi-stage relaxation. With such a procedure, heat at ambient temperature can be added between the stages in order to increase the efficiency. If heat sources are available, it is possible to increase the efficiency by heating the compressed air in the pneumatic high-pressure line 2 or in the compressed air tank 1. This enables the available energy to be stored.
  • the valves 6, 7, 8, 9, 16, 21, 24, 29 u. are controlled by an electronic control device, not shown, in order to achieve optimum efficiency. The necessary calculations are carried out in this control device and the respectively adapted decisions are made. Furthermore, the control device regulates the further supply of compressed air to the cylinder units when the high-pressure accumulator 28 is charged to a maximum or almost to the maximum. This prevents unnecessary consumption of compressed air.
  • the present invention it is possible to optimally convert the energy contained in the stored compressed air into mechanical work.
  • the invention is particularly suitable for use in motor vehicles.

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  • General Engineering & Computer Science (AREA)
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Abstract

The invention relates to a device for converting energy being stored in compressed air into mechanical work. Said device comprises the following structural parts: at least one compressed-air reservoir (1) for storing compressed air; several cylinder units (5a, 5b, 5c, 5d, 5e, 5f), whereby each unit comprises at least one pneumatic working room (10, 11) for bleeding the compressed air and at least one hydraulic working room (14, 15) for conveying the hydraulic medium, whereby the pneumatic working room (10, 11) and the hydraulic working room (14, 15) have a piston (13) respectively, whereby said pistons are coupled to each other; a hydraulic high-pressure circuit (22) being connected to the hydraulic working rooms (14, 15) of the cylinder units (5a, 5b, 5c, 5d, 5e, 5f) and being designed to transport a hydraulic medium which is exerted to high-pressure; a hydraulic motor being connected to the hydraulic high-pressure circuit and being driven by the hydraulic medium which is exerted to high-pressure. The aim of the invention is to achieve better efficiency. To this end, at least one reversing valve is provided which alternately connects the hydraulic working room (14, 15) of one cylinder unit to the hydraulic high-pressure circuit (22) or to the hydraulic working room (14, 15) of another cylinder unit (5a, 5b, 5c, 5d, 5e, 5f).

Description

Vorrichtung zur Umwandlung von in Druckluft gespeicherter Energie in mechanische ArbeitDevice for converting energy stored in compressed air into mechanical work
Die vorliegende Erfindung betrifft eine Vorrichtung zur Umwandlung von in Druckluft gespeicherter Energie in mechanische Arbeit, die folgende Bauteile aufweist:The present invention relates to a device for converting energy stored in compressed air into mechanical work, which has the following components:
- mindestens einen Druckluftbehälter zur Speicherung von Druckluft;- At least one compressed air tank for storing compressed air;
- mehrere Zylindereinheiten, jeweils mit mindestens einem Pneumatikarbeitsraum zur Entspannung der Druckluft, und mit mindestens einem Hydraulikarbeitsraum zum Fördern eines Hydraulikmediums, wobei der Pneumatikarbeitsraum und der Hydraulikarbeitsraum jeweils einen Kolben aufweisen, die miteinander gekoppelt sind;a plurality of cylinder units, each with at least one pneumatic work space for relaxing the compressed air and with at least one hydraulic work space for conveying a hydraulic medium, the pneumatic work space and the hydraulic work space each having a piston which are coupled to one another;
- eine Hydraulik-Hochdruckleitung, die mit den Hydraulikarbeitsräumen der Zylindereinheiten in Verbindung steht und die dazu ausgebildet ist, ein unter Hochdruck stehendes Hydraulikmedium zu transportieren;a high-pressure hydraulic line which is connected to the hydraulic work spaces of the cylinder units and which is designed to transport a high-pressure hydraulic medium;
- einen mit der Hydraulik-Hochdruckleitung in Verbindung stehenden Hydraulikantrieb, der vorzugsweise als Hydraulikmotor ausgebildet ist, und der von dem unter Hochdruck stehenden Hydraulikmedium angetrieben ist.- A hydraulic drive connected to the high-pressure hydraulic line, which is preferably designed as a hydraulic motor, and which is driven by the high-pressure hydraulic medium.
Die Verwendung von Druckluft als Speichermedium für Energie bietet eine Reihe von Vorteilen. Für mobile Anwendungen beispielsweise in Kraftfahrzeugen ist dabei von besonderer Bedeutung, daß sich mit Druckluftbehältern, die in Leichtbauweise ausgeführt sind, höhere Energiedichten erzielen lassen, als dies mit Batterien möglich ist. Außerdem sind Druckluftbehälter bezüglich Kosten und Lebensdauer Batterien weit überlegen. Die direkte Umwandlung der in Druckluft gespeicherten Energie in mechanische Arbeit ist jedoch für eine Reihe von Anwendungen nicht möglich oder nicht vorteilhaft. Es sind daher Systeme vorgeschlagen worden, bei denen die in der Druckluft enthaltene Energie zunächst in ein Hydrauliksystem eingebracht wird und in der Folge von einem Hydraulikmotor in mechanische Arbeit umgesetzt wird. Die Vorteile einer solchen Lösung liegen darin, daß hydraulische Systeme sehr weit ausgereift und entwickelt sind und Hydraulikmotoren klein, kompakt, kostengünstig und für eine Vielzahl verschiedene Anwendungsgebiete leicht verfügbar sind. Die vorliegende Erfindung ist jedoch auch in Verbindung mit Hydraulikzylindern als Hydraulikantrieb einsetzbar.The use of compressed air as a storage medium for energy offers a number of advantages. For mobile applications, for example in motor vehicles, it is of particular importance that compressed air containers which are of lightweight construction can achieve higher energy densities than is possible with batteries. In addition, compressed air tanks are far superior to batteries in terms of cost and service life. However, the direct conversion of the energy stored in compressed air into mechanical work is not possible or not advantageous for a number of applications. Systems have therefore been proposed in which the energy contained in the compressed air is first introduced into a hydraulic system and is subsequently converted into mechanical work by a hydraulic motor. The advantages of such a solution are that hydraulic systems are very well developed and developed and hydraulic motors are small, compact, inexpensive and easily available for a variety of different areas of application. However, the present invention can also be used in connection with hydraulic cylinders as a hydraulic drive.
Aus der WO 97/17546 ist eine Kolbenmaschine bekannt, mit der die Umwandlung der pneumatischen Energie in hydraulische Energie durchgeführt werden kann. Bei dieser Umwandlung treten zwei grundsätzliche Probleme auf: Zum einen ist zu beachten, daß die Druckluft durch die Entspannung abgekühlt wird, sofern von außen keine Wärme zugeführt wird. Eine solche adiabate Entspannung besitzt jedoch einen wesentlich geringeren Wirkungsgrad als eine isotherme Entspannung, bei der während der Expansion laufend Wärme zugeführt wird, um die Temperatur der Luft konstant zu halten. Zum anderen liegt die Druckluft beim Betrieb der Vorrichtung bei sehr stark unterschiedlichen Drücken vor. Dies liegt einerseits daran, daß der Druck in einem Druckbehälter durch die Entnahme laufend absinkt und andererseits während des Arbeitshubs einer Kolbenmaschine Druckschwankungen entstehen. Im Hydraulikkreislauf ist jedoch weitgehend konstanter Druck erwünscht, was durch einen Pufferspeicher allein nicht ohne weiteres erreicht werden kann.A piston machine is known from WO 97/17546 with which the conversion of the pneumatic energy into hydraulic energy can be carried out. There are two fundamental problems with this conversion: First, it should be noted that the compressed air is cooled by the expansion, provided that no heat is supplied from the outside. However, such an adiabatic relaxation has a much lower efficiency than an isothermal relaxation, in which heat is continuously supplied during the expansion in order to keep the temperature of the air constant. On the other hand, the compressed air is in operation the device at very different pressures. This is due on the one hand to the fact that the pressure in a pressure vessel drops continuously as a result of the removal, and on the other hand pressure fluctuations occur during the working stroke of a piston machine. In the hydraulic circuit, however, largely constant pressure is desired, which cannot be easily achieved by a buffer store alone.
In der WO 98/17492 wird ein Antriebssystem für ein Kraftfahrzeug vorgeschlagen, bei dem einem pneumohydraulischen Wandler ein in Stufen gesteuerter Druckmultiplikator nachgeschaltet ist, um den schwankenden Hydraulikdruck soweit als möglich auszugleichen.WO 98/17492 proposes a drive system for a motor vehicle in which a pressure multiplier, which is controlled in stages, is connected downstream of a pneumohydraulic converter in order to compensate the fluctuating hydraulic pressure as far as possible.
Die Nachschaltung einer eigenen Vorrichtung zum Ausgleich von Druckschwankungen ist jedoch aufwendig, und es ist schwierig, die erforderlichen Baugruppen in ein Kraftfahrzeug zu integrieren.However, the connection of a separate device to compensate for pressure fluctuations is complex and it is difficult to integrate the required assemblies into a motor vehicle.
Aufgabe der vorliegenden Erfindung ist es, diese Nachteile zu vermeiden und eine Vorrichtung der oben beschriebenen Art so weiterzubilden, daß mit möglichst geringem Aufwand ein hoher Wirkungsgrad erzielt wird.The object of the present invention is to avoid these disadvantages and to develop a device of the type described above in such a way that a high degree of efficiency is achieved with the least possible outlay.
Erfindungsgemäß ist vorgesehen, daß mindestens ein Umschaltventil vorgesehen ist, das den Hydraulikarbeitsraum einer Zylindereinheit wahlweise mit der Hydraulik-Hochdruckleitung oder mit dem Hydraulikarbeitsraum einer anderen Zylindereinheit verbindet.According to the invention it is provided that at least one changeover valve is provided which connects the hydraulic work space of a cylinder unit either with the hydraulic high pressure line or with the hydraulic work space of another cylinder unit.
Wesentlich an der vorliegenden Erfindung ist, daß durch ein einziges Gerät sowohl die Umwandlung pneumatischer Energie in hydraulische Energie als auch der Ausgleich von Druckschwankungen erzielbar ist. Grundidee der vorliegenden Erfindung ist, daß mehrere unabhängige, jedoch grundsätzlich gleichartig aufgebaute Zylindereinheiten vorgesehen sind, die je nach den aktuell herrschenden Druckverhältnissen unterschiedlich verschaltet werden. Bei Vorliegen eines hohen Drucks in dem Pneumatikarbeitsraum einer Zylindereinheit kann der entsprechende Hydraulikarbeitsraum direkt mit der Hydraulik-Hochdruckleitung verbunden werden. Sinkt der Druck jedoch unter einen vorgegebenen Grenzwert ab, so wird durch Umschalten von Steuerventilen bewirkt, daß mit den nunmehr geringerem Hydraulikdruck eine andere Zylindereinheit unterstützt wird, damit diese den erforderlichen Hydraulikdruck erzeugen kann. Der beschriebene Druckabfall kann einerseits dadurch hervorgerufen werden, daß der Pneumatikdruck durch fortschreitenden Verbrauch von Druckluft absinkt oder zum anderen durch den Verlauf der Expansionsbewegung, bei der der Druck ebenfalls absinkt. Im Extremfall können alle vorhandenen Zylindereinheiten in Serie geschaltet werden, um den erforderlichen Hydraulikdruck aufzubauen. Stehen beispielsweise die Kolbenflächen des Pneumatikteils zu den Kolbenflächen des Hydraulikteils für alle Zylindereinheiten in einem Verhältnis von 3:1, so kann auf diese Weise bei sechs Zylindereinheiten ein Gesamtübersetzungsverhältnis zwischen 3:1 und 18:1 erreicht werden. Stehen Zylindereinheiten mit unterschiedlichem Übersetzungsverhältnis zur Verfügung, kann das Gesamtübersetzungsverhältnis in einem noch größeren Bereich variiert werden.It is essential to the present invention that both the conversion of pneumatic energy into hydraulic energy and the compensation of pressure fluctuations can be achieved with a single device. The basic idea of the present invention is that several independent, but basically identical cylinder units are provided, which are connected differently depending on the current pressure conditions. If there is a high pressure in the pneumatic work space of a cylinder unit, the corresponding hydraulic work space can be connected directly to the hydraulic high-pressure line. However, if the pressure drops below a predetermined limit value, switching control valves causes another cylinder unit to be supported with the now lower hydraulic pressure so that it can generate the required hydraulic pressure. The pressure drop described can be caused on the one hand by the fact that the pneumatic pressure drops due to the progressive consumption of compressed air or on the other hand by the course of the expansion movement, during which the pressure also drops. In extreme cases, all existing cylinder units can be connected in series to build up the required hydraulic pressure. If, for example, the piston surfaces of the pneumatic part are in a ratio of 3: 1 to the piston surfaces of the hydraulic part for all cylinder units, a total transmission ratio between 3: 1 and 18: 1 can be achieved with six cylinder units. If cylinder units with different gear ratios are available, the overall gear ratio can be varied within an even wider range.
Eine besonders kompakte Ausführung der erfindungsgemäßen Vorrichtung ist dadurch möglich, dass die Zylindereinheiten doppeltwirkend mit jeweils zwei Pneumatikarbeitsräumen und zwei Hydraulikarbeitsräumen ausgebildet sind, die von einem einstückig ausgebildeten Kolben voneinander getrennt sind. Bei einer solchen Ausführungsvariante wird das Hydraulikmedium aus dem Hydraulikarbeitsraum einer Zylindereinheit dann, wenn der Druck größer ist als der Nenndruck der Hydraulik-Hochdruckleitung, mit dieser verbunden. Sinkt der Druck ab, dann schaltet das Umschaltventil um, und der Hydraulikarbeitsraum dieser Zylindereinheit wird mit dem Hydraulikarbeitsraum einer anderen Zylindereinheit verbunden, und zwar mit derjenigen, von der sich der Kolben wegbewegt. Dies bedeutet, daß der Kolben nicht nur pneumatisch sondern auch hydraulisch bewegt wird, um so einen höheren Druck erzeugen zu können.A particularly compact design of the device according to the invention is possible in that the cylinder units have double-action, each with two pneumatic work spaces and two hydraulic work spaces are formed, which are separated from each other by a one-piece piston. In such an embodiment variant, the hydraulic medium from the hydraulic work space of a cylinder unit is connected to the latter when the pressure is greater than the nominal pressure of the hydraulic high-pressure line. If the pressure drops, the changeover valve switches over, and the hydraulic working space of this cylinder unit is connected to the hydraulic working space of another cylinder unit, namely the one from which the piston moves. This means that the piston is not only moved pneumatically but also hydraulically in order to be able to generate a higher pressure.
Ein optimaler Betrieb der Vorrichtung wird dann erreicht, wenn sämtliche Ventile u. dgl. e- lektronisch gesteuert werden. Um eine solche Steuerung optimal durchführen zu können, ist es besonders günstig, wenn neben entsprechenden Druckaufnehmern auch Wegaufnehmer vorgesehen sind, die die jeweilige Stellung der Kolben erfassen.Optimal operation of the device is achieved when all valves u. Like. Be controlled electronically. In order to be able to optimally carry out such a control, it is particularly advantageous if, in addition to corresponding pressure transducers, displacement transducers are also provided which detect the respective position of the pistons.
In einer besonders bevorzugten Ausführungsvariante der Erfindung ist vorgesehen, daß die Pneumatikarbeitsräume der Zylindereinheiten über Schaltventile mit einer gemeinsamen Pneumatik-Niederdruckleitung verbunden sind, die auf ein Druckniveau in einem Bereich zwischen 5 und 15 bar ausgelegt ist. Dies bedeutet, daß in den einzelnen Zylindereinheiten die Druckluft nicht sofort auf Umgebungsdruck entspannt wird, sondern daß in der Niederdruckleitung ein gewisser Restdruck aufrecht erhalten wird. Bevorzugt kann dieser Restdruck in einer Entspannungseinrichtung dazu verwendet werden, Nebenaggregate, wie beispielsweise die Lichtmaschine, eine Pumpe für ein Lenkhilfeaggregat oder einen Bremskraftverstärker anzutreiben. Als Entspannungseinrichtung kann beispielsweise eine herkömmliche kleine Turbine oder ein Flügelzellenmotor eingesetzt werden.In a particularly preferred embodiment variant of the invention it is provided that the pneumatic working spaces of the cylinder units are connected via switching valves to a common low-pressure pneumatic line which is designed for a pressure level in a range between 5 and 15 bar. This means that in the individual cylinder units the compressed air is not immediately released to ambient pressure, but that a certain residual pressure is maintained in the low pressure line. This residual pressure can preferably be used in a relaxation device to drive auxiliary units such as the alternator, a pump for a power steering unit or a brake booster. For example, a conventional small turbine or a vane motor can be used as the relaxation device.
Der Wirkungsgrad der Vorrichtung in Bezug auf die in der Druckluft gespeicherten Energie kann dadurch erhöht werden, daß eine Einrichtung zur Erwärmung der Druckluft im Druckluftbehälter oder in einer Pneumatik-Hochdruckleitung vorgesehen ist, die die Druckluftbehälter mit den Pneumatikarbeitsräumen der Zylindereinheiten verbindet. Zur Erwärmung der Druckluft können entweder natürliche Energiequellen, wie z. B. durch Sonneneinstrahlung erwärmte Karosserieteile, die Abwärme von anderen Aggregaten oder eine spezielle dafür konzipierte Heizung oder beides herangezogen werden. Durch die Verwendung von Abwärme zur Erwärmung der Druckluft kann ein theoretischer Wirkungsgrad der Anlage von sogar über 100 % erreicht werden. Bei einer besonders begünstigten Ausfuhrungsvariante, bei der die Zylindereinheiten innerhalb eines Niederdruckbehälters für das Hydraulikmedium angeordnet sind, wird in einfacher Weise das Hydraulikmedium erwärmt, um dem System Energie zuzuführen.The efficiency of the device in relation to the energy stored in the compressed air can be increased by providing a device for heating the compressed air in the compressed air container or in a pneumatic high-pressure line, which connects the compressed air container to the pneumatic work spaces of the cylinder units. To heat the compressed air, either natural energy sources, such as. B. body parts heated by solar radiation, the waste heat from other units or a specially designed heater or both can be used. By using waste heat to heat the compressed air, a theoretical system efficiency of over 100% can be achieved. In a particularly preferred embodiment variant, in which the cylinder units are arranged within a low-pressure container for the hydraulic medium, the hydraulic medium is heated in a simple manner in order to supply energy to the system.
Um die Energieverluste zufolge der nicht isothermen Entspannung von Druckluft zu verringern, kann vorgesehen sein, daß die Zylindereinheiten mit Wärmetauschern zum Einbringen von Wärme während der Entspannung der Druckluft ausgestattet sind. Durch die günstige Auslegung der Maschine ist ein relativ langsamer Betrieb möglich. Dadurch kann während der Arbeitshübe über die Zylinderwand der Druckluft eine gewisse Wärmemenge zugeführt werden. Durch Ausbildung der Zylindereinheiten in der Art, wie sie in der WO 97/17546 beschrieben ist, kann der Wärmeübergang weiter verbessert werden und der Wirkungsgrad erhöht werden.In order to reduce the energy losses due to the non-isothermal expansion of compressed air, it can be provided that the cylinder units are equipped with heat exchangers for introducing heat during the expansion of the compressed air. Due to the favorable design of the machine, a relatively slow operation is possible. As a result, a certain amount of heat can be supplied to the compressed air via the cylinder wall during the working strokes become. By designing the cylinder units in the manner described in WO 97/17546, the heat transfer can be further improved and the efficiency increased.
Um in einfacher Weise jede beliebige Zylindereinheit zur Unterstützung jeder anderen beliebigen Zylindereinheit zusammenschalten zu können, ist besonders bevorzugt eine in Form einer geschlossenen Schleife ausgebildete Druckunterstützungsleitung vorgesehen, die über die Umschaltventile mit den Hydraulikarbeitsräumen aller Zylindereinheiten in Verbindung steht und die sich aus den einzelnen Versorgungsleitungen zusammensetzt.In order to be able to interconnect any cylinder unit to support any other cylinder unit in a simple manner, a pressure support line designed in the form of a closed loop is particularly preferably provided, which is connected to the hydraulic work spaces of all cylinder units via the changeover valves and which is composed of the individual supply lines .
Geringfügige verbleibende Druckschwankungen in der Hydraulik-Hochdruckleitung können dadurch ausgeglichen werden, daß ein Hydraulik-Hochdruckspeicher vorgesehen ist, der mit der Hydraulik-Hochdruckleitung in Verbindung steht. Wesentlich ist der Hydraulik- Hochdruckspeicher zur Erreichung eines schnellen Ansprechverhaltens bei der Beschleunigung oder beim Anfahren.Slight remaining pressure fluctuations in the hydraulic high-pressure line can be compensated for by the fact that a hydraulic high-pressure accumulator is provided which is connected to the hydraulic high-pressure line. The hydraulic high-pressure accumulator is essential to achieve a quick response when accelerating or starting.
Eine weitgehende Freiheit des Zusammenschaltens der einzelnen Zylindereinheiten ist insbesondere dadurch gegeben, daß die Zylindereinheiten unabhängig voneinander beweglich ausgeführt sind. Dies bedeutet, daß die Kolben der einzelnen Zylindereinheiten nicht über eine Kurbelwelle oder andere mechanische Verbindungen gekoppelt sind. Auf diese Weise wird nicht nur eine mechanische Vereinfachung erzielt, sondern es kann auch die pneumatische und hydraulische Beschaltung besser optimiert werden.An extensive freedom of interconnection of the individual cylinder units is given in particular by the fact that the cylinder units are designed to be movable independently of one another. This means that the pistons of the individual cylinder units are not coupled via a crankshaft or other mechanical connections. In this way, not only is mechanical simplification achieved, but the pneumatic and hydraulic circuitry can also be better optimized.
Besonders bevorzugt ist es, wenn weiters eine elektronische Steuerungseinrichtung für die Umschaltventile vorgesehen ist, die dazu ausgebildet ist, ein Umschaltventil des Hydraulikarbeitsraums einer ersten Zylindereinheit zur Verbindung mit dem Hydraulikarbeitsraum einer weiteren Zylindereinheit umzuschalten, wenn der Druck in dem Hydraulikarbeitsraum der ersten Zylindereinheit nicht höher ist als der in der Hydraulik-Hochdruckleitung erforderliche Druck.It is particularly preferred if an electronic control device for the changeover valves is also provided, which is designed to switch a changeover valve of the hydraulic workspace of a first cylinder unit for connection to the hydraulic workspace of a further cylinder unit when the pressure in the hydraulic workspace of the first cylinder unit is not higher than the pressure required in the high pressure hydraulic line.
Die Erfindung wird anhand des in den Figuren dargestellten Ausführungsbeispiels näher beschrieben. Fig. 1 zeigt einen Schaltplan eines Ausführungsbeispiels der vorliegenden Erfindung, Fig. 2 ein Detail von Fig. 1 in vergrößertem Maßstab.The invention is described in more detail with reference to the embodiment shown in the figures. Fig. 1 shows a circuit diagram of an embodiment of the present invention, Fig. 2 shows a detail of Fig. 1 on an enlarged scale.
Die erfindungsgemäße Vorrichtung besteht aus drei Druckluftbehältern 1 zur Speicherung von Druckluft bis zu einem Nenndruck von 300 bar. Für die Anwendung in Kraftfahrzeugen sind diese Druckluftbehälter 1 in Leichtbau aus faserverstärktem Kunststoff ausgeführt. Die Druckluftbehälter 1 stehen über eine Pneumatik-Hochdruckleitung 2, in der ein Absperrorgan 3 und ein Filter 4 angeordnet ist, mit den Zylindereinheiten 5 a, 5b, 5 c, 5d, 5e und 5f in Verbindung. Die detaillierte Beschaltung der ersten Zylindereinheit 5a ist in der Fig. 2 in vergrößertem Maßstab dargestellt. Die übrigen Zylindereinheiten 5b bis 5f sind gleichartig ausgebildet. Die Pneumatik-Hochdruckleitung 2 führt zu gegenläufig geschalteten Steuerventilen 6, 7, 8, 9, die die Pneumatik-Hochdruckleitung 2 wahlweise mit einem ersten Pneumatikarbeitsraum 10 oder mit einem zweiten Pneumatikarbeitsraum 11 verbinden. Der jeweils andere Pneumatikarbeitsraum 10, 11 ist über die Steuerventile 6 bis 9 mit einer Pneumatik- Niederdruckleitung 12 verbunden. Die Ventile 6 bis 9 sind jeweils so gesteuert, daß die Lage der Ventile 6 und 9 gleich ist und die Lage der Ventile 7 und 8 entgegengesetzt von der der Ventile 6 und 9 ist. Durch die unterschiedlichen Druckverhältnisse in den Pneumatikarbeitsräumen 10 und 11 wird der Kolben 13 der Zylindereinheit 5a hin- und herbewegt. Durch diese Bewegung wird Hydrauliköl, das sich in Hydraulikarbeitsräumen 14 bzw. 15 befindet, zu einem weiteren Schaltventil 16 geführt. Ein Sicherheitsventil 17 begrenzt den Druck auf den maximal zulässigen Druck. Durch das weitere Schaltventil 16 wird jeweils einer der Hydraulikarbeitsräume 14, 15 mit einer Hydraulikzufuhrleitung 18 verbunden, während der andere mit einer Hydraulikforderleitung 19 verbunden wird. Ein Drucksensor 20 überwacht den Druck in der Hydraulikforderleitung 19. Ein Umschaltventil 21 verbindet die Hydraulikforderleitung 19 wahlweise mit einer Hydraulik-Hochdruckleitung 22 oder mit der Zufuhrleitung 18d der Zylindereinheit 5d. Im ersten Fall wird die Zufuhrleitung 18d gleichzeitig mit einer Hydraulik-Niederdruckleitung 23 verbunden. Eine Verbindungsleitung 39 mit einem Rückschlagventil 38 dient dazu, auch bei Stillstand der Vorrichtung das Hochdrucksystem gefüllt zu halten.The device according to the invention consists of three compressed air containers 1 for storing compressed air up to a nominal pressure of 300 bar. For use in motor vehicles, these compressed air tanks 1 are made of fiber-reinforced plastic in a lightweight construction. The compressed air tanks 1 are connected to the cylinder units 5 a, 5b, 5 c, 5d, 5e and 5f via a pneumatic high-pressure line 2, in which a shut-off device 3 and a filter 4 are arranged. The detailed circuitry of the first cylinder unit 5a is shown in FIG. 2 on an enlarged scale. The remaining cylinder units 5b to 5f are of the same design. The pneumatic high-pressure line 2 leads to control valves 6, 7, 8, 9 connected in opposite directions, which optionally connect the pneumatic high-pressure line 2 to a first pneumatic work space 10 or to a second pneumatic work space 11. The other pneumatic work space 10, 11 is connected via the control valves 6 to 9 with a pneumatic Low pressure line 12 connected. The valves 6 to 9 are each controlled so that the position of the valves 6 and 9 is the same and the position of the valves 7 and 8 is opposite to that of the valves 6 and 9. Due to the different pressure conditions in the pneumatic work spaces 10 and 11, the piston 13 of the cylinder unit 5a is moved back and forth. As a result of this movement, hydraulic oil, which is located in hydraulic workrooms 14 and 15, is guided to a further switching valve 16. A safety valve 17 limits the pressure to the maximum permissible pressure. The additional switching valve 16 connects one of the hydraulic working spaces 14, 15 to a hydraulic supply line 18, while the other is connected to a hydraulic supply line 19. A pressure sensor 20 monitors the pressure in the hydraulic supply line 19. A changeover valve 21 connects the hydraulic supply line 19 either to a hydraulic high-pressure line 22 or to the supply line 18d of the cylinder unit 5d. In the first case, the supply line 18d is simultaneously connected to a hydraulic low-pressure line 23. A connecting line 39 with a check valve 38 serves to keep the high-pressure system filled even when the device is at a standstill.
Lagesensoren 24 sind dazu vorgesehen, die Stellung jedes Kolbens 13 zu erfassen. In der dargestellten Ausführungsvariante erfassen drei Lagesensoren 24 die Endlagen des Kolbens 13 und eine Mittelstellung. Zusammen mit den Drucksensoren 20 ist es damit möglich, jederzeit über die erforderlichen Informationen über den Zustand des Systems zu verfügen. Insbesondere die Erfassung der Mittellage der Kolben 23 ist wichtig, da zu diesem Zeitpunkt im Pneumatikarbeitsraum der jeweiligen Zylindereinheit etwa der doppelte Druck herrschen sollte wie in der Pneumatik-Niederdruckleitung 12. Etwaige Abweichungen werden beim nächsten Arbeitshub durch eine Veränderung der Steuerzeiten der Ventile 6, 7, 8, 9 berücksichtigt.Position sensors 24 are provided to detect the position of each piston 13. In the embodiment variant shown, three position sensors 24 detect the end positions of the piston 13 and a middle position. Together with the pressure sensors 20, it is thus possible to have the necessary information about the state of the system at all times. In particular, the detection of the central position of the pistons 23 is important, since at this point there should be approximately twice the pressure in the pneumatic working space of the respective cylinder unit as in the pneumatic low-pressure line 12. Any deviations will become apparent during the next working stroke due to a change in the control times of the valves 6, 7 , 8, 9 are taken into account.
Die einzelnen Versorgungsleitungen 18a bis 18f sind über die Schaltventile 16 und 21 zu einer geschlossenen Druckunterstützungsleitung verbunden, die die einzelnen Zylindereinheiten 5a bis 5f versorgen. Die gemeinsame Hydraulik-Hochdruckleitung 22 ist über ein Steuerventil 24 und ein Verstellventil 25 mit einem Hydraulikmotor 26 verbunden. Eine entsprechende Verstellvorrichtung ist mit 27 gekennzeichnet.The individual supply lines 18a to 18f are connected via the switching valves 16 and 21 to form a closed pressure support line, which supply the individual cylinder units 5a to 5f. The common hydraulic high-pressure line 22 is connected to a hydraulic motor 26 via a control valve 24 and an adjusting valve 25. A corresponding adjustment device is identified by 27.
Um kurzfristige Druckschwankungen in der Hydraulik-Hochdruckleitung 22 auszugleichen, ist ein Hydraulik-Hochdruckspeicher 28 vorgesehen, der über ein Steuerventil 29 und zwei Druckbegrenzungsventile 30, 31 mit der Hydraulik-Hochdruckleitung 22 in Verbindung steht.In order to compensate for short-term pressure fluctuations in the hydraulic high-pressure line 22, a hydraulic high-pressure accumulator 28 is provided, which is connected to the hydraulic high-pressure line 22 via a control valve 29 and two pressure-limiting valves 30, 31.
Die Hydraulik-Niederdruckleitung 23 wird durch einen Niederdruckbehälter 32 über einen Filter 33 mit Hydraulikmedium versorgt. Ein Drucksensor 34 überwacht den Druck im Niederdrucksystem. In den Figuren ist der Niederdruckbehälter 32 als selbständiger Bauteil dargestellt. Es kann jedoch dieser Behälter 32 so ausgebildet sein, daß alle Zylindereinheiten 5a, 5b, 5c, 5d, 5e, 5f und die damit zusammenhängenden Ventile 6, 7, 8, 9, 16 und 21 im Ölbad innerhalb des Niederdruckbehälters 32 angeordnet sind. Auf diese Weise kann der Bauraum optimal ausgenützt werden und der Wärmeübergang an den Zylinderwänden verbessert werden. In der Pneumatik-Niederdruckleitung 12 wird ein Druck aufrecht erhalten, der in einem Bereich zwischen 5 und 15 bar liegt. Über einen Flügelzellenmotor 35 wird die Luft der Pneumatik-Niederdruckleitung 12 auf einen geringen Druck im Bereich des Umgebungsluftdrucks entspannt und über einen Schalldämpfer 36 nach außen abströmen gelassen. Der Flügelzellenmotor 35 treibt nur schematisch dargestellte Nebenaggregate 37a, 37b, 37c und 37d an. Bei dieser Nebenaggregaten handelt es sich um eine Lichtmaschine, Servopumpen für eine Lenkungsunterstützung oder einen Bremskraftverstärker, den Kompressor einer Klimaanlage od. dgl. Eines dieser Nebenaggregate, und zwar in der Zeichnung das mit 37c bezeichnete, ist als Hydraulik-Hochdruckpumpe ausgeführt, die eingangsseitig mit der Hydraulik-Niederdruckleitung 23 und ausgangsseitig mit der Hydraulik-Hochdruckleitung 22 verbunden ist. Durch diese Hydraulik-Hochdruckpumpe kann in besonders einfacher Weise eine verlustfreie Regelung der Drehzahl des Flügelzellenmotors erreicht werden. Ist nämlich die an dem Flügelzellenmotor 35 zur Verfügung stehende Leistung größer als die Leistungsaufnahme der Nebenaggregate, so wird durch die Hydraulikpumpe 37c die zur Verfügung stehende Leistung dazu verwendet, Öl in der Hochdrucksystem einzuspeisen. Auf diese Weise kann der Verbrauch an Druckluft verringert werden, was die Reichweite eines entsprechenden Fahrzeugs erhöht.The hydraulic low-pressure line 23 is supplied with hydraulic medium by a low-pressure tank 32 via a filter 33. A pressure sensor 34 monitors the pressure in the low pressure system. In the figures, the low-pressure container 32 is shown as an independent component. However, this container 32 can be designed such that all the cylinder units 5a, 5b, 5c, 5d, 5e, 5f and the associated valves 6, 7, 8, 9, 16 and 21 are arranged in the oil bath within the low-pressure container 32. In this way, the installation space can be optimally used and the heat transfer on the cylinder walls can be improved. A pressure which is in a range between 5 and 15 bar is maintained in the pneumatic low-pressure line 12. The air of the pneumatic low-pressure line 12 is expanded to a low pressure in the area of the ambient air pressure by means of a vane-type motor 35 and is discharged to the outside via a silencer 36. The vane motor 35 only drives auxiliary units 37a, 37b, 37c and 37d, which are shown schematically. This auxiliary unit is an alternator, servo pumps for steering assistance or a brake booster, the compressor of an air conditioning system or the like the hydraulic low pressure line 23 and the output side is connected to the hydraulic high pressure line 22. This hydraulic high-pressure pump enables loss-free control of the speed of the vane motor to be achieved in a particularly simple manner. If the power available on the vane motor 35 is greater than the power consumption of the auxiliary units, the hydraulic pump 37c uses the power available to feed oil into the high-pressure system. In this way, the consumption of compressed air can be reduced, which increases the range of a corresponding vehicle.
In der Folge wird die Funktionsweise der erfindungsgemäßen Vorrichtung anhand des Schaltungsdiagramms der Fig. 1 und 2 erklärt werden. Nach dem Aufladen der Druckluftbehälter 1 liegt in der Pneumatik-Hochdruckleitung 2 Druckluft mit einem Druck von etwa 300 bar vor. Wenn sich beispielsweise der Kolben 13 der Zylindereinheit 5a in seiner oberen Endlage befindet, was durch die Lagesensoren 24 erfaßt wird, dann wird das Steuerventil 7 für einen vorbestimmten kurzen Zeitraum geöffnet. Der erforderliche Zeitraum wird von einer nicht dargestellten Steuereinrichtung so berechnet, daß in dem Pneumatikarbeitsraum 10 am Ende der Hubbewegung ein Druck vorliegt, der geringfügig größer ist, als der in der Pneumatik- Niederdruckleitung 12 eingestellte Druck. Durch die in dem Pneumatikarbeitsraum 10 vorliegende Druckluft wird der Kolben 13 nach unten bewegt. Dementsprechend wird im Hydraulikarbeitsraum 15 entsprechend dem Verhältnis der wirksamen Kolbenflächen ein Hydraulikdruck aufgebaut. Solange dieser Druck größer ist als der Druck in der Hydraulik- Hochdruckleitung 22, ist das Ventil so geschaltet, daß die Hydraulikförderleitung 19 mit der Hydraulik-Hochdruckleitung 22 verbunden ist. Wenn sich die Druckluft in den Pneumatikarbeitsraum 10 soweit entspannt hat, daß eine weitere Bewegung des Kolbens 13 gegen den Druck in der Hydraulik-Hochdruckleitung nicht mehr möglich ist, wird das Steuerventil 21 umgeschaltet. Auf diese Weise wird der Hydraulikarbeitsraum 15 mit der Hydraulikzufuhrlei- tung 18d für die nächste Zylindereinheit 5d verbunden. Auf diese Weise wird erreicht, daß derjenige Hydraulikarbeitsraum der Zylindereinheit 5d, von dem sich der Kolben wegbewegt, nicht aus der Hydraulik-Niederdruckleitung 23 mit Öl versorgt wird, sondern mit dem Öl höheren Drucks aus der Zylindereinheit 5a. Auf diese Weise wird eine zusätzliche Kraft auf den Kolben ausgeübt, so dass auch in einer späteren Phase des Expansionszyklus ein ausreichend hoher Hydraulikdruck erzeugt wird, um Öl in die Hydraulik-Hochdruckleitung 22 einspeisen zu können. Der Zeitpunkt des Umschaltens des Ventils 21 kann aus dem anliegenden Pneu- matikdruck und dem Übersetzungsverhältnis des Kolbens 13 berechnet werden, solange die jeweilige Zylindereinheit mit Hydrauliköl aus der Hydraulik-Niederdruckleitung 23 versorgt wird. Falls jedoch von der jeweils vorgeschalteten Zylindereinheit unter Druck stehendes Hydrauliköl nachgefordert wird, muß die Zusatzkraft bei dieser Berechnung berücksichtigt werden. Da der jeweilige Druck durch den Drucksensor 20 gemessen wird, kann die entsprechende Berechnung ausgeführt werden.The mode of operation of the device according to the invention will be explained below with reference to the circuit diagram of FIGS. 1 and 2. After the compressed air container 1 has been charged, there is compressed air in the pneumatic high-pressure line 2 at a pressure of approximately 300 bar. For example, when the piston 13 of the cylinder unit 5a is in its upper end position, which is detected by the position sensors 24, the control valve 7 is opened for a predetermined short period of time. The required period of time is calculated by a control device (not shown) in such a way that there is a pressure in the pneumatic work space 10 at the end of the lifting movement which is slightly greater than the pressure set in the pneumatic low-pressure line 12. The piston 13 is moved downward by the compressed air present in the pneumatic work space 10. Accordingly, a hydraulic pressure is built up in the hydraulic working space 15 in accordance with the ratio of the effective piston areas. As long as this pressure is greater than the pressure in the hydraulic high-pressure line 22, the valve is switched so that the hydraulic delivery line 19 is connected to the hydraulic high-pressure line 22. When the compressed air in the pneumatic work space 10 has relaxed to such an extent that further movement of the piston 13 against the pressure in the hydraulic high-pressure line is no longer possible, the control valve 21 is switched over. In this way, the hydraulic work space 15 is connected to the hydraulic supply line 18d for the next cylinder unit 5d. In this way it is achieved that that hydraulic working space of the cylinder unit 5d from which the piston moves is not supplied with oil from the hydraulic low-pressure line 23, but with the oil of higher pressure from the cylinder unit 5a. In this way, an additional force is exerted on the piston, so that even in a later phase of the expansion cycle, a sufficiently high hydraulic pressure is generated in order to be able to feed oil into the hydraulic high-pressure line 22. The time at which the valve 21 is switched over can be determined from the connected tire Matikdruck and the transmission ratio of the piston 13 are calculated as long as the respective cylinder unit is supplied with hydraulic oil from the hydraulic low pressure line 23. However, if hydraulic oil under pressure is required from the upstream cylinder unit, the additional force must be taken into account in this calculation. Since the respective pressure is measured by the pressure sensor 20, the corresponding calculation can be carried out.
Wenn der Druck in den Druckluftbehältern 1 absinkt, werden die Ventile 6, 7, 8, 9 entsprechend länger offen gehalten, um den entsprechenden Druck in der Pneumatik- Niederdruckleitung 12 letztlich zu erreichen. Bei abnehmenden Druck in den Druckluftbehältern wird auch das Problem des Wirkungsgradverlustes zufolge der Abkühlung der Druckluft während der Entspannung geringer.When the pressure in the compressed air tanks 1 drops, the valves 6, 7, 8, 9 are kept open for a correspondingly longer time in order to ultimately achieve the corresponding pressure in the pneumatic low-pressure line 12. As the pressure in the compressed air tanks decreases, the problem of loss of efficiency due to the cooling of the compressed air during relaxation also diminishes.
Es ist offensichtlich, daß es im Sinne der Erfindung nicht nur möglich ist, zwei Zylindereinheiten zur Verstärkung zusammenzuschalten, sondern dass auch eine mehrstufige Ausbildung möglich ist. Im Extremfall können alle Zylindereinheiten hintereinander geschaltet werden.It is obvious that within the meaning of the invention it is not only possible to interconnect two cylinder units for reinforcement, but that a multi-stage training is also possible. In extreme cases, all cylinder units can be connected in series.
Die in den Fig. 1 und 2 dargestellte Ausführungsvariante geht von einer einstufigen Entspannung der Druckluft von dem Druck der Pneumatik-Hochdruckleitung 2 auf den Druck der Pneumatik-Niederdruckleitung 12 aus. Je nach Anwendungsfall ist es auch möglich, ein Pneumatikmitteldrucksystem zwischenzuschalten, um eine mehrstufige Entspannung zu ermöglichen. Bei einer solchen Vorgangsweise kann zwischen den Stufen Wärme mit Umgebungstemperatur zugeführt werden, um den Wirkungsgrad zu erhöhen. Falls Wärmequellen zur Verfügung stehen, ist es zur Erhöhung des Wirkungsgrades möglich, die Druckluft in der Pneumatik-Hochdruckleitung 2 oder im Druckluftbehälter 1 zu erwärmen. Dadurch kann die zur Verfügung stehende Energie gespeichert werden.The embodiment variant shown in FIGS. 1 and 2 is based on a one-stage expansion of the compressed air from the pressure of the pneumatic high-pressure line 2 to the pressure of the pneumatic low-pressure line 12. Depending on the application, it is also possible to interpose a pneumatic medium pressure system to enable multi-stage relaxation. With such a procedure, heat at ambient temperature can be added between the stages in order to increase the efficiency. If heat sources are available, it is possible to increase the efficiency by heating the compressed air in the pneumatic high-pressure line 2 or in the compressed air tank 1. This enables the available energy to be stored.
Die in den Figuren dargestellten Ventile 6, 7, 8, 9, 16, 21, 24, 29 u. dgl. werden von einer nicht dargestellten elektronischen Steuerungseinrichtung angesteuert, um einen optimalen Wirkungsgrad zu erzielen. In dieser Steuerungseinrichtung werden die erforderlichen Berechnungen durchgeführt und die jeweils angepaßten Entscheidungen gefällt. Weiters regelt die Steuerungseinrichtung die weitere Zufuhr von Druckluft zu den Zylindereinheiten ab, wenn der Hochdruckspeicher 28 maximal oder nahezu maximal geladen ist. Dadurch wird ein nicht notwendiger Verbrauch an Druckluft verhindert.The valves 6, 7, 8, 9, 16, 21, 24, 29 u. The like. Are controlled by an electronic control device, not shown, in order to achieve optimum efficiency. The necessary calculations are carried out in this control device and the respectively adapted decisions are made. Furthermore, the control device regulates the further supply of compressed air to the cylinder units when the high-pressure accumulator 28 is charged to a maximum or almost to the maximum. This prevents unnecessary consumption of compressed air.
Mit der vorliegenden Erfindung ist es möglich, die in der gespeicherten Druckluft enthaltene Energie in optimaler Weise in mechanische Arbeit umzusetzen. Die Erfindung ist besonders für den Einsatz in Kraftfahrzeugen geeignet. With the present invention, it is possible to optimally convert the energy contained in the stored compressed air into mechanical work. The invention is particularly suitable for use in motor vehicles.

Claims

P A T E N T A N S P R Ü C H E PATENT CLAIMS
1. Vorrichtung zur Umwandlung von in Druckluft gespeicherter Energie in mechanische Arbeit, die folgende Bauteile aufweist:1. Device for converting energy stored in compressed air into mechanical work, comprising the following components:
- mindestens einen Druckluftbehälter (1) zur Speicherung von Druckluft;- At least one compressed air tank (1) for storing compressed air;
- mehrere Zylindereinheiten (5a, 5b, 5c, 5d, 5e, 5f), jeweils mit mindestens einem Pneumatikarbeitsraum (10, 11) zur Entspannung der Druckluft, und mit mindestens einem Hydraulikarbeitsraum (14, 15) zum Fördern eines Hydraulikmediums, wobei der Pneumatikarbeitsraum (10, 11) und der Hydraulikarbeitsraum (14, 15) jeweils einen Kolben (13) aufweisen, die miteinander gekoppelt sind;- Several cylinder units (5a, 5b, 5c, 5d, 5e, 5f), each with at least one pneumatic work space (10, 11) for relaxing the compressed air, and with at least one hydraulic work space (14, 15) for conveying a hydraulic medium, the pneumatic work space (10, 11) and the hydraulic work space (14, 15) each have a piston (13) which are coupled to one another;
- eine Hydraulik-Hochdruckleitung (22), die mit den Hydraulikarbeitsräumen (14, 15) der Zylindereinheiten (5a, 5b, 5c, 5d, 5e, 5f) in Verbindung steht und die dazu ausgebildet ist, ein unter Hochdruck stehendes Hydraulikmedium zu transportieren;- A high-pressure hydraulic line (22) which is connected to the hydraulic work spaces (14, 15) of the cylinder units (5a, 5b, 5c, 5d, 5e, 5f) and which is designed to transport a high-pressure hydraulic medium;
- einen mit der Hydraulik-Hochdruckleitung in Verbindung stehenden Hydraulikantrieb, der vorzugsweise als Hydraulikmotor ausgebildet ist, und der von dem unter Hochdruck stehenden Hydraulikmedium angetrieben ist, dadurch gekennzeichnet, daß mindestens ein Umschaltventil vorgesehen ist, das den Hydraulikarbeitsraum (14, 15) einer Zylindereinheit wahlweise mit der Hydraulik- Hochdruckleitung (22) oder mit dem Hydraulikarbeitsraum (14, 15) einer anderen Zylindereinheit (5a, 5b, 5c, 5 d, 5 e, 5 f) verbindet.- A hydraulic drive connected to the high-pressure hydraulic line, which is preferably designed as a hydraulic motor, and which is driven by the high-pressure hydraulic medium, characterized in that at least one changeover valve is provided which defines the hydraulic working space (14, 15) of a cylinder unit either with the hydraulic high pressure line (22) or with the hydraulic work space (14, 15) of another cylinder unit (5a, 5b, 5c, 5 d, 5 e, 5 f).
2. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß die Zylindereinheiten doppeltwirkend mit jeweils zwei Pneumatikarbeitsräumen (10, 11) und zwei Hydraulikarbeitsräumen (14, 15) ausgebildet sind, die von einem einstückig ausgebildeten Kolben (13) voneinander getrennt sind.2. Device according to claim 1, characterized in that the cylinder units are double-acting, each with two pneumatic work spaces (10, 11) and two hydraulic work spaces (14, 15) are formed, which are separated from one another by a piston (13).
3. Vorrichtung nach einem der Ansprüche 1 oder 2, dadurch gekennzeichnet, daß in den Zylindereinheiten (5a, 5b, 5c, 5d, 5e, 5f) Wegaufnehmer (24) vorgesehen sind, die die jeweilige Stellung des Kolbens (13) erfassen.3. Device according to one of claims 1 or 2, characterized in that in the cylinder units (5a, 5b, 5c, 5d, 5e, 5f) displacement transducers (24) are provided which detect the respective position of the piston (13).
4. Vorrichtung nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß die Pneumatikarbeitsräume (10, 11) der Zylindereinheiten (5a, 5b, 5c, 5d, 5e, 5f) über Schaltventile (6, 7, 8, 9) mit einer gemeinsamen Pneumatik-Niederdruckleitung (12) verbunden sind, die auf ein Druckniveau in einem Bereich zwischen 5 und 15 bar ausgelegt ist.4. Device according to one of claims 1 to 3, characterized in that the pneumatic work spaces (10, 11) of the cylinder units (5a, 5b, 5c, 5d, 5e, 5f) via switching valves (6, 7, 8, 9) with a Common pneumatic low pressure line (12) are connected, which is designed for a pressure level in a range between 5 and 15 bar.
5. Vorrichtung nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß ein Pneumatikmitteldrucksystem vorgesehen ist, um die Druckluft, die in den Druckluftbehältern (1) gespeichert ist, mehrstufig zu entspannen. 5. Device according to one of claims 1 to 3, characterized in that a pneumatic medium pressure system is provided to relax the compressed air, which is stored in the compressed air containers (1), in several stages.
6. Vorrichtung nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß eine Einrichtung zur Erwärmung der Druckluft im Druckluftbehälter (1) oder in einer Pneumatik- Hochdruckleitung (2) vorgesehen ist, die die Druckluftbehälter (1) mit den Pneumatikarbeitsräumen (10, 11) der Zylindereinheiten (5a, 5b, 5c, 5d, 5e, 5f) verbindet.6. Device according to one of claims 1 to 5, characterized in that a device for heating the compressed air in the compressed air tank (1) or in a pneumatic high-pressure line (2) is provided, which the compressed air tank (1) with the pneumatic work spaces (10, 11) of the cylinder units (5a, 5b, 5c, 5d, 5e, 5f) connects.
7. Vorrichtung nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß die Zylindereinheiten mit Wärmetauschern zum Einbringen von Wärme während der Entspannung der Druckluft ausgestattet sind.7. Device according to one of claims 1 to 6, characterized in that the cylinder units are equipped with heat exchangers for introducing heat during the expansion of the compressed air.
8. Vorrichtung nach einem der Ansprüche 1 bis 7, dadurch gekennzeichnet, daß eine in Form einer geschlossenen Schleife ausgebildete Druckunterstützungsleitung (18a, 18b, 18c, 18d, 18e, 18f) vorgesehen ist, die über Umschaltventile (16, 21) mit den Hydraulikarbeitsräumen (14, 15) aller Zylindereinheiten (5a, 5b, 5c, 5d, 5e, 5f) in Verbindung steht.8. Device according to one of claims 1 to 7, characterized in that a pressure support line (18a, 18b, 18c, 18d, 18e, 18f) in the form of a closed loop is provided, which via changeover valves (16, 21) with the hydraulic work spaces (14, 15) of all cylinder units (5a, 5b, 5c, 5d, 5e, 5f) is connected.
9. Vorrichtung nach einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, daß ein Hydraulik-Hochdruckspeicher (28) vorgesehen ist, der mit der Hydraulik-Hochdruckleitung (22) in Verbindung steht.9. Device according to one of claims 1 to 8, characterized in that a hydraulic high-pressure accumulator (28) is provided which is connected to the hydraulic high-pressure line (22).
10. Vorrichtung nach einem der Ansprüche 1 bis 9, dadurch gekennzeichnet, daß eine Entspannungseinrichtung (35) vorgesehen ist, die mit der Pneumatik-Niederdruckleitung (12) in Verbindung steht, und die zum Antrieb von Nebenaggregaten (37a, 37b, 37c, 37d) bestimmt ist.10. Device according to one of claims 1 to 9, characterized in that a relaxation device (35) is provided, which is connected to the pneumatic low-pressure line (12), and for driving auxiliary units (37a, 37b, 37c, 37d ) is determined.
11. Vorrichtung nach einem der Ansprüche 1 bis 9, dadurch gekennzeichnet, daß die Zylindereinheiten (5a, 5b, 5c, 5d, 5e, 5f) unabhängig voneinander beweglich ausgeführt sind.11. Device according to one of claims 1 to 9, characterized in that the cylinder units (5a, 5b, 5c, 5d, 5e, 5f) are designed to be movable independently of one another.
12. Vorrichtung nach einem der Ansprüche 1 bis 11, dadurch gekennzeichnet, daß weiters eine elektronische Steuerungseinrichtung für die Umschaltventile (16, 21) vorgesehen ist, die dazu ausgebildet ist, ein Umschaltventil (16, 21) des Hydraulikarbeitsraums (14, 15) einer ersten Zylindereinheit (5a, 5b, 5c, 5d, 5e, 5f) zur Verbindung mit dem Hydraulikarbeitsraum einer weiteren Zylindereinheit (5a, 5b, 5c, 5d, 5e, 5f) umzuschalten, wenn der Druck in dem Hydraulikarbeitsraum der ersten Zylindereinheit (5a, 5b, 5c, 5d, 5e, 5f) nicht höher ist als der in der Hydraulik-Hochdruckleitung (22) erforderliche Druck.12. Device according to one of claims 1 to 11, characterized in that further an electronic control device for the switching valves (16, 21) is provided, which is designed to a switching valve (16, 21) of the hydraulic work space (14, 15) one to switch the first cylinder unit (5a, 5b, 5c, 5d, 5e, 5f) for connection to the hydraulic working space of a further cylinder unit (5a, 5b, 5c, 5d, 5e, 5f) when the pressure in the hydraulic working space of the first cylinder unit (5a, 5b, 5c, 5d, 5e, 5f) is not higher than the pressure required in the hydraulic high-pressure line (22).
13. Vorrichtung nach einem der Ansprüche 1 bis 12, dadurch gekennzeichnet, daß die Zylindereinheiten (5a, 5b, 5c, 5d, 5e, 5f) innerhalb eines Niederdruckbehälters (32) für das Hydraulikmedium angeordnet sind. 13. Device according to one of claims 1 to 12, characterized in that the cylinder units (5a, 5b, 5c, 5d, 5e, 5f) are arranged within a low-pressure container (32) for the hydraulic medium.
PCT/AT1999/000307 1998-12-22 1999-12-21 Device for converting energy being stored in compressed air into mechanical work WO2000037800A1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
JP2000589832A JP2002533609A (en) 1998-12-22 1999-12-21 A device that converts energy stored in compressed air into mechanical work
BR9916452-3A BR9916452A (en) 1998-12-22 1999-12-21 Device for converting stored energy in compressed air into mechanical work
EP99963158A EP1141549A1 (en) 1998-12-22 1999-12-21 Device for converting energy being stored in compressed air into mechanical work
AU19581/00A AU1958100A (en) 1998-12-22 1999-12-21 Device for converting energy being stored in compressed air into mechanical work

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ATA2139/98 1998-12-22
AT213998A AT406984B (en) 1998-12-22 1998-12-22 DEVICE FOR CONVERTING ENERGY STORED IN COMPRESSED AIR IN MECHANICAL WORK

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WO (1) WO2000037800A1 (en)

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AU1958100A (en) 2000-07-12
EP1141549A1 (en) 2001-10-10
BR9916452A (en) 2001-09-04
JP2002533609A (en) 2002-10-08
ATA213998A (en) 2000-03-15
AT406984B (en) 2000-11-27

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