CN116638909A

CN116638909A - Level control system and level control method for vehicle

Info

Publication number: CN116638909A
Application number: CN202310144695.XA
Authority: CN
Inventors: 菲利普·肖伯
Original assignee: Amk Holdings Ltd
Current assignee: Amk Holdings Ltd
Priority date: 2022-02-23
Filing date: 2023-02-21
Publication date: 2023-08-25
Also published as: DE102022104326B4; DE102022104326A1

Abstract

The invention relates to a level control system and a level control method for a vehicle, by means of which a vehicle body is damped relative to an axle, comprising a compressor, an air spring and a first compressed air reservoir for a first pressure level, wherein the suction side of the compressor is connected to the atmosphere via an atmospheric line, wherein the air spring and the first compressed air reservoir are connected to the compression side of the compressor via a supply line, and further comprising a first pressure line by means of which the first compressed air reservoir can be connected to the suction side of the compressor via a first valve. A second compressed air reservoir is provided for a second pressure level, which is higher than the first pressure level, wherein the second compressed air reservoir can be connected to the compression side of the compressor via a supply line, wherein the second compressed air reservoir can be connected to the reservoir line of the first compressed air reservoir via a second connecting valve via a second connecting line, so that the level control system can be operated in cascade.

Description

Level control system and level control method for vehicle

Technical Field

The invention relates to a level control system for a vehicle, by means of which a vehicle body is damped relative to at least one axle, comprising a compressor, at least one air spring, at least one first compressed air reservoir for a first pressure level and at least one first pressure line.

The invention also relates to a method for controlling the level of a vehicle, by means of which the vehicle body is damped relative to at least one axle.

Background

Level control systems for height control of air from a pressure reservoir are known in the art.

A level control device of the generic type is described, for example, in DE 10 2008 034 240 B4. The level control apparatus comprises a two-stage compressor, also referred to hereinafter as compressor, having a first compression stage and a second compression stage. The pressure medium is precompressed in the first compression stage and is introduced via the connecting line into the second compression stage and is further compressed there. The compressed pressure medium can be introduced into a pressure medium storage vessel. The pressure medium stored in the pressure medium storage vessel can be fed via the pressure medium line and the switching valve to the suction chamber of the second compression stage and thereby be compressed further, which can be referred to as a "booster function" and increase the energy efficiency, since the energy from the residual compressed air in the pressure medium storage vessel can be used to generate compressed air. The pressure medium can continue to be fed to the air spring, so that the vehicle can be lifted. In the level control device, a multistage compressor is used in order to bring the air spring and the pressure medium reservoir to a high pressure level by means of multistage compression of the compressor.

DE 10 2012 006 382 A1 also discloses a further pressure medium supply for operating a pneumatic device, wherein a two-stage compressor is included in the pressure medium supply. The precompressed compressed air from the air spring and the compressed air reservoir can thus be introduced simultaneously into the suction chamber of the second compressor stage as well as into the compression chamber of the first compressor stage, so that the compressor can be pre-charged with compressed air from the air spring and the compressed air reservoir. In DE 10 2012 006 382 A1, the desired pressure level is also achieved by means of a multistage compressor.

The same type is also referred to DE 10 2012 010390a1, in which a supercharging function by directing the residual compressed air of the compressed air reservoir back to the suction side of the primary compressor is proposed.

With the known level control systems, the problem arises that the supercharging function in the pneumatic system has to be activated frequently in order to obtain the desired pressure level, and that further compressed air energy storages, which can reduce the number and duration of compressor activations, in particular for repeated compressed air demands, cannot be integrated. For this reason, a compromise between high volume flow and high pressure levels must be considered when arranging the multi-stage compressor, so that optimum efficiency and energy efficiency cannot be achieved.

Furthermore, in the frequent operating states of the previously known compressed air systems, the operating noise increases, so that excessive noise is generated.

Disclosure of Invention

Based on the above prior art, the object of the present invention is to provide a level control system for a vehicle and a method for level control of a vehicle, which enable better efficiency and higher energy efficiency and a significant increase in the lifting speed, wherein the compressor system of the level control system can be integrated compactly in the vehicle with a spatially smaller construction size and the operating noise of the compressor system is reduced.

This object is achieved by a level control system having the features of claim 1 and a method having the features of claim 10. Advantageous modifications of the invention are the subject matter of the dependent claims.

The invention relates to a level control system for a vehicle, by means of which a vehicle body is damped relative to at least one axle, comprising:

a compressor (compressor), wherein the suction side of the compressor is connected to the atmosphere via an atmospheric line,

at least one air spring and at least one first compressed air reservoir for a first pressure level, wherein the at least one air spring and the first compressed air reservoir are connected to the compression side of the compressor by a supply line,

-at least one first pressure line through which the first compressed air reservoir can be connected to the suction side of the compressor via at least one first valve.

According to the invention, at least one second compressed air reservoir is provided for a second pressure level, which is higher than the first pressure level of the first compressed air reservoir, wherein the second compressed air reservoir can be connected to the compression side of the compressor via the supply line, wherein the second compressed air reservoir can be connected to the reservoir line of the first compressed air reservoir via at least one second connecting valve via a second connecting line, so that the level control system can be operated in cascade.

A level control system is therefore proposed, in which at least one two-stage compressed air storage system is comprised, which comprises a first compressed air storage for a first pressure level and a second compressed air storage for a second pressure level. Wherein the second pressure level is higher than the first pressure level. Hereby it is achieved that the low-pressure air and the high-pressure air are stored separately in the level control system. The suction chamber of the compressor may be connected to the atmosphere through a check valve that opens in the suction direction of the compressor.

The two compressed air reservoirs can be connected to the compression side of the compressor via a supply line and via a reservoir line, respectively, wherein a reservoir valve is arranged in each of the two reservoir lines. The second compressed air reservoir can advantageously be connected via at least one second connecting valve to a reservoir line of the first compressed air reservoir by means of a second connecting line. It is thereby achieved that the first compressed air reservoir is filled to the first pressure level by air sucked from the atmosphere and compressed by the compressor via the supply line and its reservoir line when the storage valve of the first compressed air reservoir is opened. Furthermore, when a second connecting valve arranged in the second connecting line is opened, the generated compressed air is fed via the second connecting line to the second compressed air reservoir, and the second compressed air reservoir is thereby filled to a second pressure level.

The feature that the first compressed air reservoir can be connected via at least one first valve with the suction side of the compressor by means of a first pressure line makes it possible to pre-charge the compressor with compressed air from the first compressed air reservoir to a pressure level still contained in the first compressed air reservoir. As a result, the compressor is started at the initial pressure provided by the pre-charge for compression, and the pressure level of the level control system is further increased by the compressor. Thereby providing a supercharging function. The further compressed air is then introduced into the second compressed air reservoir via the supply line with the storage valve of the second compressed air reservoir open, wherein the storage valve and the second connecting valve of the first compressed air reservoir are closed. This advantageously ensures that the second compressed air reservoir can be filled to the second pressure level by the pressurization function.

Advantageously, the compressor is pre-charged (precharge) by a pre-filled compressed air reservoir in order to then re-compress the compressed air to the next higher pressure level so that the level control system can be operated in cascade. Furthermore, it is advantageously achieved that the air spring can be filled in a short time, so that the air spring can be rapidly pressurized to the desired pressure level.

Advantageously, the first compressed air reservoir is used to achieve short-term pre-charging of the compressor. This increases the volume flow and maximum pressure when lifting the vehicle. This advantageously achieves a so-called power flow function or supercharging function.

Furthermore, it is advantageously achieved that with the compressed air reservoir, an additional return function (if necessary with the addition of additional lines and valves) can be implemented in the level control system, so that the precompressed compressed air can be conducted from the air spring via the compressor into at least one compressed air reservoir, preferably into the second high-pressure reservoir.

It is furthermore advantageous that, depending on the storage dimensions of the compressed air reservoir, it can be embodied as a closed level control system or as a closed air supply, so that the pressure from the air spring is not discharged to the environment in the event of non-use, but is stored back in one compressed air reservoir. In other words, the compressed air from the air spring is conducted to the compressed air reservoir and stored there.

It is also advantageous that the pressure level of the level control system can be raised above the pressure level that the compressor can apply from atmospheric pressure. Advantageously, the filling of the pressure reservoir to the maximum pressure is performed in a plurality of steps, whereby the pressure level requirements on the compressor can be reduced. The pressure stage in the level control system is thus not provided directly in the compressor, but via at least two, in particular more, arranged compressed air reservoirs, so that a multistage compressor is not required nor is it necessary to arrange. This can improve efficiency and energy efficiency and significantly increase the lifting speed. Furthermore, it is advantageously achieved that the compressor is compactly integrated in the vehicle with a spatially smaller overall size, and that the operating noise of the compressor can be reduced due to the low number of compressor stages.

It may also be advantageous to include a pressure sensor for detecting the air pressure in the compressed air reservoir and the air spring and for generating a pressure signal in response thereto, wherein the pressure sensor is arranged in the supply line. The boost function may be activated by feeding back the compressed air remaining in the first compressed air reservoir based on the pressure signal.

Furthermore, at least one decoupling valve is advantageously arranged in the supply line, so that the supply line with the connected compressed air reservoir and air spring can be decoupled from the compressed air flow escaping from the dryer during the pressure measurement.

Advantageously, at least one air filter is additionally arranged in the atmospheric line, so that air from the atmosphere can be filtered before entering the compressor.

In an advantageous variant of the level control system, at least one third compressed air reservoir for a third pressure level which is higher than the second pressure level of the second compressed air reservoir can be arranged, wherein the third compressed air reservoir can be connected to the compression side of the compressor via a supply line, wherein the second compressed air reservoir can be connected to the suction side of the compressor via at least one second valve via a second pressure line, and wherein the third compressed air reservoir can be connected to a reservoir line of the second compressed air reservoir via a third connecting line via at least one third connecting valve. To this end, a three-stage compressed air storage system is realized in this embodiment, which comprises a first compressed air reservoir for a first pressure level, a second compressed air reservoir for a second pressure level and a third compressed air reservoir for a third pressure level, wherein the first pressure level is lower than the second pressure level and the second pressure level is lower than the third pressure value. Accordingly, a compressed air storage system is provided for storing low pressure air, medium pressure air and high pressure air, wherein a supercharging function from the low pressure level and the medium pressure level can be achieved. Thus a three-stage cascade with two booster stages can be constructed.

It is thereby achieved that air sucked from the atmosphere and compressed by the compressor can be introduced into the first, second and third compressed air reservoirs via the supply lines when the storage valve of the first compressed air reservoir is open and the second and third connection valves are open.

The second compressed air reservoir is connected via a second valve to the suction side of the compressor by means of a second pressure line, whereby it is possible to pre-charge the compressor not only with pressure from the low-pressure stage of the first compressed air reservoir, but also with pressure from the medium-pressure stage of the second compressed air reservoir. The pressurizing function can thus be achieved by leading back compressed air not only from the first compressed air reservoir but also from the second compressed air reservoir. The pre-compressed air may be further compressed by a compressor and delivered to the third compressed air reservoir via a supply line and an open storage valve of the third compressed air reservoir. Furthermore, the first and second compressed air reservoirs may advantageously be used only for priming the compressor. Advantageously, in this embodiment additional return functions can be achieved by adding more lines and valves, so that pre-compressed air from the air springs can be led directly or optionally via the compressor into the at least one compressed air reservoir. Thus, a closed system can be realized, in which air can be conducted from the compressed air reservoir to the air spring and back again.

In a further advantageous variant, the compressor can be designed in two stages and can comprise at least a first compression stage having a first suction chamber and a first compression chamber and a second compression stage having a second suction chamber and a second compression chamber, wherein the first suction chamber is connected to the atmosphere via an atmospheric line, the first compression chamber is connected to the second suction chamber, and the air spring, the first compressed air reservoir, the second compressed air reservoir and preferably the third compressed air reservoir are connected to the second compression chamber of the second compression stage via a supply line. For this purpose, a two-stage compressor is provided. Advantageously, the first and second compression stages may be used together to fill a compressed air reservoir and/or an air spring. It is furthermore advantageous if only the second compression stage is used for rapid filling of the air spring to high pressure with compressed air from the second and/or third compressed air reservoir. It is also advantageous that the air spring can be filled in a short time by compressing the pre-compressed air from the first and/or the second compressed air reservoir. Thus, the air spring can be rapidly pressurized to a desired pressure level.

In a further advantageous variant, the first compressed air reservoir can be connected via a first valve to a first suction chamber of the first compression stage and/or to a second suction chamber of the second compression stage, wherein the first suction chamber is connected to the atmosphere via an atmospheric line. Thus, the compressor may be pre-charged with pressure from the first compressed air reservoir by the first and/or second compression stage. In this regard, when the first valve is open, compressed air from the first compressed air reservoir may be fed to the second suction chamber of the second compression stage, whereby the second compression stage is pre-filled with compressed air from the first compressed air reservoir and further used to fill the second and/or third compressed air reservoir and to lift the vehicle. Thereby the lifting speed can be increased. Alternatively, the first compression stage may be used for priming. Furthermore, both compression stages can be pre-filled with pre-compressed air from the first compressed air reservoir, wherein the compressed air is fed to both the first suction chamber and the second suction chamber.

As an alternative to the previous embodiment, in a further advantageous variant, the second compressed air reservoir can be connected via a second pressure line with the first suction chamber of the first compression stage and/or the second suction chamber of the second compression stage by a second valve. The compressor can thus be pre-charged with pressure from the second compressed air reservoir by the first and/or second compression stage, so that compressed air from the second compressed air reservoir is fed via the second pressure line to the first and/or second suction chamber with the second valve open.

In principle, the invention can be implemented using a cylinder compressor with a wobble piston. However, a rotary compressor having a rotary piston rather than a wobble piston is preferably used. These make the operation smoother and the noise level lower. Furthermore, rotary compressors have similar aerodynamic properties as cylinder compressors, but lower pressure levels, for which the volumetric flow increases. The rotary compressor is therefore suitable in combination with the cascade connection according to the invention for achieving higher pressure levels and higher volume flows. In a further advantageous variant of this context, the compressor can be designed as a one-stage or two-stage compressor, in particular the first and/or the second compression stage as a rotary compressor, in particular a scroll compressor. The scroll compressor can thus generate air pressure without difficulty and with reduced noise and vibration, and comprises two intermeshing scroll members whose opposite movements compress gas. Advantageously, due to its valveless design, the scroll compressor is particularly low maintenance and quiet. Even under extreme environmental conditions, such as rain, dust, ice deposits and low temperatures, scroll compressors may be used due to their stable nature.

In a further advantageous variant, the second and/or third connecting valve can be designed as a return valve, whereby compressed air can be blocked in the direction from the second and/or third compressed air reservoir to the first and/or second compressed air reservoir. This can advantageously be achieved in that the pressurizing function is performed by the compressed air reservoir for the lower pressure level, without pressure escaping from the compressed air reservoir for the higher pressure level.

In a further advantageous variant, the first valve and the second valve can be designed as two-position two-way valves. Thereby, the first and second valves may be switched to different circuit positions. The first and second valves may be electrically controlled, wherein the valves may be connected to electrical terminals of the control device. Advantageously, the first and second valves are electrically operated and no complex mechanical connections or circumferential pneumatic pilot control is provided for operating the valves. The use of electrically operated valves allows for very simple installation at low cost.

Alternatively, the first and second valves may be pneumatically controlled. In contrast to electrically operated valves, a connection for compressed air is provided instead of an electrical connection, wherein the valve can be switched by controlling the compressed air. The use of pneumatic valves allows low outlay to be achieved and additional electrical components with a risk of failure to be dispensed with.

In a further advantageous development, the first compressed air reservoir can have a larger storage volume than the second compressed air reservoir, and preferably the second compressed air reservoir can have a larger storage volume than the third compressed air reservoir. A sufficient volume of compressed air can thereby be taken from the first and/or second compressed air reservoir and be prepared for recompression. In this way, a sufficient compressed air with high pressure can be produced for the second and/or third compressed air reservoir, respectively.

In a juxtaposed aspect, the invention relates to a method for level control of a vehicle with a level control system as described above, by means of which the vehicle body is buffered relative to at least one axle.

According to the invention, it is proposed that compressed air from the first compressed air reservoir is fed via the first valve to the suction side of the compressor by means of the first pressure line, that the pressure of the compressed air is increased by the compressor and that the compressed air is fed via the supply line and preferably via the at least one storage valve to the second and/or third compressed air reservoir.

A method for level control of a vehicle is therefore proposed, in which a compressor is pre-charged with pressure from a first compressed air reservoir. The pressure of the compressed air from the first compressed air reservoir may be increased by recompression. The further compressed air is led via a supply line into the second and/or third compressed air reservoir. In this way, the compressed air reservoir may be filled to its maximum pressure level. In this way, it is advantageously achieved that the pressure level of the level control system is brought to a high pressure level in several stages without having to use a compressor with a higher operating pressure and a drive motor with a high power.

In an advantageous variant, the first compressed air reservoir can be filled to at least the first pressure level by sucking in air which has entered from the atmosphere and is compressed by the compressor when the storage valve of the first compressed air reservoir is open. Advantageously, the pressure in the first compressed air reservoir can be increased directly by the compressed air generated by the compressor.

In a further advantageous variant, the second compressed air reservoir can be filled to at least the second pressure level by sucking in air coming in from the atmosphere or air which is led back to the suction side by the first compressed air reservoir and compressed by the compressor, with the second connection valve closed and the storage valve of the second compressed air reservoir opened. The second compressed air reservoir can be filled to its maximum pressure level in such a way that air taken in from the atmosphere is first compressed by the compressor and then directly fed to the second compressed air reservoir. In addition, the compressed air from the first compressed air reservoir can be led back to the compressor first and be compressed there further. The recompressed compressed air may then be fed to the second compressed air reservoir, so that the second compressed air reservoir may be filled to a maximum pressure level.

In a further advantageous variant, the third compressed air reservoir can be filled to at least a third pressure level by sucking in air coming in from the atmosphere or air guided back to the suction side by the first and/or second compressed air reservoir and compressed by the compressor, with the third connection valve closed and the storage valve of the third compressed air reservoir open. Thereby, a plurality of possibilities for filling the third compressed air reservoir can be provided. The third compressed air reservoir may be filled directly with air drawn in from the atmosphere and compressed by the compressor. The third compressed air reservoir may also be filled with compressed air which is led from the first and/or the second compressed air reservoir to the compressor and is further compressed there to a higher pressure level.

In a further advantageous variant, the vehicle body can be lifted by means of an air spring, so that compressed air from the second and/or third compressed air reservoir is conducted into the air spring. The vehicle can thus be lifted by the second compressed air reservoir in the two-stage compressed air reservoir system and/or by the third compressed air reservoir in the three-stage compressed air reservoir system. This advantageously makes it possible for the air spring to be filled directly via the compressed air reservoir without the compressor having to be started.

In a further advantageous development, for lifting the vehicle body, compressed air of the first or second compressed air reservoir, which is fed to the intake side of the compressor via the first pressure line and/or the second pressure line and is further compressed by the compressor, can be fed into the air spring. Thereby lifting the vehicle and increasing the lifting speed by the supercharging function.

In a further advantageous development, compressed air from the compression side of the compressor can be fed directly to the air spring via the supply line for lifting the vehicle body. That is, the air spring may be directly filled by the compressor.

Drawings

Other advantages of the invention are presented in the drawings and the corresponding description of the drawings.

Embodiments of the invention are illustrated in the accompanying drawings. The figures, description and claims contain many combined features. Those skilled in the art can readily consider these features alone and combine them into other combinations of interest. In the accompanying drawings:

FIG. 1 is a schematic diagram of a horizontal control system according to the prior art;

FIG. 2 is a schematic diagram of a level control system having a first compressed air reservoir according to the prior art;

FIG. 3 is a schematic diagram of a first embodiment of a level control system according to the present invention;

FIG. 4 is a schematic diagram of another embodiment of a level control system of the present invention;

FIG. 5 is a schematic diagram of another embodiment of a level control system of the present invention;

FIG. 6 is a schematic diagram of another embodiment of a level control system of the present invention;

FIG. 7 is a schematic diagram of another embodiment of a level control system of the present invention;

FIG. 8 is a schematic diagram of another embodiment of a level control system of the present invention;

FIG. 9 is a schematic diagram of another embodiment of a level control system of the present invention;

FIG. 10 is a schematic view of another embodiment of the level control system of the present invention;

FIG. 11 is a schematic view of another embodiment of the level control system of the present invention;

FIG. 12 is a schematic view of another embodiment of the level control system of the present invention;

FIG. 13 is a schematic view of another embodiment of a level control system of the present invention;

FIGS. 14a-14c are schematic illustrations of a first embodiment of a method for level control of a vehicle according to the present invention;

FIG. 15 is a schematic view of another embodiment of a method according to the present invention;

fig. 16 is a schematic diagram of another embodiment of a method according to the invention.

In the figures, identical or similar parts are identified with identical reference numerals.

Detailed Description

A level control system 10 for a vehicle as known in the art is schematically shown in fig. 1. The level control system 10 is designed to operate an air spring 18 of a vehicle. Each air spring 18 is connected to the supply line 26 via an air spring valve 72, wherein the air spring valve 72 is designed as a two-position two-way valve 52. The level control system 10 has a single-stage compressor 12 that can be operated by an electric motor 58 that is connected to the atmospheric line 16 on the suction side 14 of the compressor 12. A supply line 26 containing a dryer 54 is connected to the compression side 30. An inlet valve 48 is arranged on the suction side 14 and a switching valve 62 is arranged on the compression side 30, both valves being designed as check valves 50. A discharge line 74, which contains a discharge valve 66 designed as a two-position two-way valve 52 and opens to the atmosphere downstream of the discharge valve 66, branches off from the supply line 26 between the compressor 12 and the dryer 54. A decoupling valve 64, which is embodied as a two-position two-way valve 52, is arranged in the supply line 26, so that the compressed air flow escaping from the dryer 54 can be decoupled when the pressure is measured on the air spring 18. Furthermore, an air filter 56 with a muffler is provided in the atmospheric line 16, so that air from the atmosphere can be filtered first before entering the compressor 12. In addition, a pressure sensor 68 for detecting the air pressure in the air spring 18 and for generating a pressure signal in response thereto is included, wherein the pressure sensor 68 is contained in the supply line 26.

Another level control system 10 for a vehicle, known in the art, is schematically illustrated in fig. 2. The level control system 10 is substantially identical to the embodiment according to fig. 1. However, this embodiment differs from the embodiment shown in fig. 1 in that the first compressed air reservoir 20 can be connected to the suction side 14 of the compressor 12 via a first valve 46, which is designed as a two-position two-way valve 52, by means of a first pressure line 28. With the first valve 46 open, compressed air may be delivered from the first compressed air reservoir 20 to the suction side 14 of the compressor 12, such that the compressed air may be further compressed by the compressor 12. Thus, the compressor 12 may be pre-charged with pressure from the first compressed air reservoir 20. The first compressed air reservoir 20 can also be connected further via a reservoir line 34 to the supply line 26 via a reservoir valve 70a designed as a two-position two-way valve 52. Thus, with the storage valve 70a open, compressed air generated by the compressor 12 may be directed into the first compressed air reservoir 20. Furthermore, the suction side 14 of the compressor 12 can be connected to the atmosphere via the atmospheric line 16 via two inlet valves 48, wherein the inlet valves 48 are designed as check valves 50 which open in the suction direction of the compressor 12.

A first embodiment of a level control system 10 according to the present invention is schematically shown in fig. 3. The compressor 12 is included in the level control system 10, wherein the suction side 14 of the compressor 12 may be connected to the atmosphere via an atmospheric line 16 via two inlet valves 48. Furthermore, four air springs 18 and a first compressed air reservoir 20 for a first pressure level are provided, wherein the air springs 18 can each be connected to the supply line 26 via an air spring valve 72. The first compressed air reservoir 20 can be connected via a reservoir line 34 to the supply line 26 via a reservoir valve 70a, so that, when the reservoir valve 70a is open, compressed air can be introduced into the first compressed air reservoir 20 via the supply line 26 and the reservoir line 34. Furthermore, the first compressed air reservoir 20 may be connected to the suction side 14 of the compressor 12 via a first valve 46 via a first pressure line 28, such that compressed air from the first compressed air reservoir 20 may be conducted back to the suction side 14. Thus, a supercharging function can be achieved. Also arranged in this level control system 10 is a second compressed air reservoir 22 for a second pressure level, which is higher than the first pressure level of the first compressed air reservoir 20, wherein the second compressed air reservoir 22 can be connected via a second connecting valve 32 to a reservoir line 34 of the first compressed air reservoir 20 by way of a second connecting line 38. Thus, when the compressed air reservoirs 20, 22 are filled, compressed air discharged from the compression side 30 of the compressor 12 can be introduced into the first compressed air reservoir 20 via the reservoir line 34 with the storage valve 70a open and into the second compressed air reservoir 22 via the reservoir line 34 and the second connection line 38 of the first compressed air reservoir 20 with the second connection valve 32 open. Furthermore, the second compressed air reservoir 22 can be connected via the reservoir line 34, which contains the reservoir valve 70b, via the supply line 26 to the compression side 30, so that, by means of the supercharging function, compressed air recompressed by the compressor 12 is introduced at an increased pressure via the supply line 26 via the reservoir line 34 with the reservoir valve 70b open, and can be filled to a second pressure level. Thus, the level control system 10 may operate in cascade. The reservoir valves 70a, 70b, the first valve 46 and the air spring valve 72 are designed as two-position two-way valves 52. Furthermore, the second connecting valve 32 is designed as a check valve 50. Other configurations of the level control system 10 are substantially identical to the level control system shown in fig. 2.

Fig. 4 schematically illustrates another embodiment of a level control system 10 according to the present invention. The level control system 10 is substantially identical to the structural configuration of the embodiment according to fig. 3. The level control system 10 shown in fig. 4 differs from the embodiment in fig. 3 in that a third compressed air reservoir 24 is provided for a third pressure level, wherein the third pressure level is higher than the second pressure level of the second compressed air reservoir 22. The third compressed air reservoir 24 can be connected via a reservoir line 34 to the compression side 30 of the compressor 12 via a supply line 26, in which reservoir line a reservoir valve 70c designed as a two-position two-way valve 52 is arranged, so that, with the reservoir valve 70c open, compressed air from the compression side 30 can be introduced into the third compressed air reservoir 24 via the supply line 26 and the reservoir line 34. To pre-charge the compressor 12, not only the first compressed air reservoir 20 is connected to the suction side 14 of the compressor 12 via the first pressure line 28, but also the second compressed air reservoir 22 is connected to the suction side 14 of the compressor 12 via the second pressure line 42 via the second valve 60 designed as a two-position two-way valve 52, so that the compressor 12 can be pre-charged with pressure from the second compressed air reservoir 22 with the second valve 60 open. The third compressed air reservoir 24 can also be connected via a third connecting line 40 to the reservoir line 34 of the second compressed air reservoir 22 via a third connecting valve 44 designed as a check valve 50. The third compressed air reservoir 24 can thus be filled with compressed air up to a third pressure level via the supply line 26 and via the connecting line 40 and the reservoir line 34.

Fig. 5 shows another embodiment of a level control system 10 according to the present invention. The level control system 10 is substantially identical to the structural configuration of the embodiment according to fig. 3. However, the level control system 10 shown in fig. 5 differs from the embodiment of fig. 3 in that a two-stage compressor 12 is used. The compressor 12 has a first compression stage 12a with a first suction chamber 14a and a first compression chamber 30a and a second compression stage 12b with a second suction chamber 14b and a second compression chamber 30b, wherein the first suction chamber 14a is connected to the atmosphere via an inlet valve 48 in the form of a check valve 50 via an atmospheric line 16. Furthermore, the first compression chamber 30a can also be connected to the second suction chamber 14b via two inlet valves 48, which are designed as check valves 50. Furthermore, the air spring 18, the first compressed air reservoir 20 and the second compressed air reservoir 22 are connected via a supply line 26 to a second compression chamber 30b of the second compression stage 12 b. Furthermore, the first compressed air reservoir 20 can be connected via a first valve 46, designed as a two-position two-way valve 52, and via an inlet valve 48, to the second suction chamber 14b of the second compression stage 12b by means of the first pressure line 28, so that the second compression stage 12b can be pre-filled with pressure from the first compressed air reservoir 20. Furthermore, a non-return valve 50, which opens in the suction direction of the first compression stage 12a and is provided as an inlet valve 48, is provided upstream of the suction chamber 14a of the first compression stage 12a, so that the first compression stage 12a can be connected to the atmosphere.

Another embodiment of a level control system 10 according to the present invention is shown in fig. 6. The level control system 10 is substantially identical to the structural configuration of the embodiment according to fig. 5. Whereas the horizontal control system 10 shown in fig. 6 differs from the embodiment in fig. 5 in that the first compressed air reservoir 20 is connectable via a first pressure line 28, in which a first valve 46 is built in, to the first suction chamber 14a of the first compression stage 12a of the compressor 12, wherein the first valve 46 is designed as a two-position two-way valve 52. Thereby, compressed air can be led back from the first compressed air reservoir 20 into the first suction chamber 14 a. With the second connecting valve 32 closed and with the storage valve 70b open, the second compressed air reservoir 22 can be filled to at least a second pressure level by compressed air further compressed by the first compression stage 12 a.

Fig. 7 shows another embodiment of a level control system 10 according to the present invention. The level control system 10 essentially corresponds to the combined structural configuration of the embodiments according to fig. 5 and 6. The level control system 10 shown in fig. 7 differs from the embodiment in fig. 6 in that the embodiment according to fig. 5 is characterized in that the first compressed air reservoir 20 can be connected not only via the first pressure line 28 via the first valve 46 to the first suction chamber 14a of the first compression stage 12a of the compressor 12, but also via the second pressure line 42 via the second valve 60 to the second suction chamber 14b of the second compression stage 12b of the compressor 12. The first and second valves 46, 60 are designed as two-position two-way valves 52. Thus, the pre-charging of the compressor 12 may be performed by pre-charging the first compression stage 12a and pre-charging the second compression stage 12b with pressure from the first compressed air reservoir 20.

Fig. 8 shows another embodiment of a level control system 10 according to the present invention. The level control system 10 is substantially identical to the structural configuration of the embodiment according to fig. 4. The horizontal control system 10 shown in fig. 8, however, differs from the embodiment of fig. 4 in that a two-stage compressor 12 is provided. The compressor 12 has a first compression stage 12a with a first suction chamber 14a and a first compression chamber 30a and a second compression stage 12b with a second suction chamber 14b and a second compression chamber 30b, wherein the first suction chamber 14a can be connected to the atmosphere via an inlet valve 48 in the form of a check valve 50 via an atmospheric line 16. To charge the compressor 12, the first compressed air reservoir 20 can be connected via a first valve 46 to the second suction chamber 14b of the second compression stage 12b by means of the first pressure line 28, wherein the first valve 46 is designed as a two-position two-way valve 52. In this embodiment, the second compressed air reservoir 22 can also be connected via a second valve 60 designed as a two-position two-way valve 52 to the second suction chamber 14b via a second pressure line 42, so that the compressor 12 can be pre-charged with not only the pressure from the first compressed air reservoir 20 but also the pressure from the second compressed air reservoir 22.

Another embodiment of a level control system 10 according to the present invention is shown in fig. 9. The level control system 10 is substantially identical to the structural configuration of the embodiment shown in fig. 8. However, the horizontal control system 10 shown in fig. 9 differs from the embodiment in fig. 8 in that the first and second compressed air reservoirs 20, 22 may be connected to the first suction chamber 14a of the first compression stage 12b of the compressor 12 through the first and second pressure lines 28, 42 via the first and second valves 46, 60, respectively. The first and second valves 46, 60 are designed as two-position two-way valves 52. Thus, the compressor 12 can be pre-charged with compressed air not only from the first compressed air reservoir 20 but also from the second compressed air reservoir 22.

Another embodiment of a level control system 10 according to the present invention is shown in fig. 10. The level control system 10 is substantially identical to the structural configuration of the embodiment shown in fig. 9. However, the level control system 10 shown in fig. 10 differs from the embodiment shown in fig. 9 in that the second compressed air reservoir 22 can be connected to the second suction chamber 14b of the second compression stage 12b of the compressor 12 by means of a second valve 60 configured as a two-position two-way valve 52 via a second pressure line 42. Thus, compressed air can be conducted both from the first compressed air reservoir 20 into the first suction chamber 14a of the first compression stage 12a and from the second compressed air reservoir 22 into the second suction chamber 14b. Whereby the compressor 12 can be pre-charged.

Fig. 11 shows another embodiment of a level control system 10 according to the present invention. The level control system 10 is substantially identical to the structural configuration of the embodiment shown in fig. 10. However, the level control system 10 shown in fig. 11 differs from the embodiment in fig. 10 in that the first compressed air reservoir 20 can be connected not only via the first valve 46 by the first pressure line 28 to the first suction chamber 14a of the first compression stage 12a of the compressor 12, but also via the further first valve 46 by the first pressure line 28 to the second suction chamber 14b of the second compression stage 12b of the compressor 12. Since compressed air can be conducted from the first compressed air reservoir 20 into the first compression stage 12a and into the second compression stage 12b, the pre-charging of the compressor 12 with pressure from the first compressed air reservoir 20 can take place not only via the first compression stage 12a but also via the second compression stage 12 b. The first valve 46 is designed as a two-position two-way valve 52.

Another embodiment of a level control system 10 according to the present invention is shown in fig. 12. The level control system 10 is substantially identical to the structural configuration of the embodiment shown in fig. 9. However, the level control system 10 shown in fig. 12 differs from the embodiment in fig. 9 in that the second compressed air reservoir 22 can be connected not only to the first suction chamber 14a of the first compression stage 12a of the compressor 12 by means of the second pressure line 42 via the second valve 60, but also to the second suction chamber 14b of the second compression stage 12b of the compressor 12 by means of the second pressure line 42 via the further second valve 60. The second valve 46 is designed as a two-position two-way valve 52. Compressed air can thus be fed from the second compressed air reservoir 22 to the first suction chamber 14a and the second suction chamber 14b, so that the compressor 12 can be pre-charged with pressure from the second compressed air reservoir 22, not only via the first compression stage 12a but also via the second compression stage 12 b.

Another embodiment of a level control system 10 according to the present invention is shown in fig. 13. The level control system 10 is substantially identical in structural configuration to the embodiment shown in fig. 12. However, the level control system 10 shown in fig. 13 differs from the embodiment in fig. 12 in that the first compressed air reservoir 20 can be connected not only to the first suction chamber 14a of the first compression stage 12a of the compressor 12 by the first pressure line 28 via the first valve 46, but also to the second suction chamber 14b of the second compression stage 12b of the compressor 12 by the first pressure line 28 via the further first valve 46. The first valve 46 is designed as a two-position two-way valve 52. In this embodiment, compressed air from the first compressed air reservoir 20 may be delivered to the first and second suction chambers 14a, 14b. In addition, compressed air from the second compressed air reservoir 22 may also be fed into the first and second suction chambers 14a, 14b. It is thus achieved that the compressor 12 can be pre-charged not only with pressure from the first compressed air reservoir 20, but also with pressure from the second compressed air reservoir 22, wherein the pre-charging can take place not only via the first compression stage 12a but also via the second compression stage 12 b.

Various methods of level control of a vehicle by means of a level control system as described above are shown in fig. 14a to 16.

A first embodiment of a method for horizontal control of a vehicle according to the invention is schematically shown in fig. 14a to 14 c.

According to fig. 14a, air from the atmosphere is first compressed to a pressure level by a compressor 12 having a suction side 14 and a compression side 30, and is then introduced via a supply line 26 via a reservoir line 34 into the first compressed air reservoir 20 and via a second connecting line 38 into the second compressed air reservoir 22 for a second pressure level with the second connecting valve 32 open. The second connecting valve 32 is designed as a check valve 50.

According to fig. 14b, the compressed air stored in the first compressed air reservoir 20 is led back to the suction side 14 via the first pressure line 28 with the first valve 46 open and is further compressed by the compressor 12. The recompressed compressed air is fed via the supply line 26 via the reservoir line 34 to the second compressed air reservoir 22 with the second connection valve 32 closed and stored there. The second compressed air reservoir 22 may be filled with compressed air up to a second pressure level.

According to fig. 14c, the compressed air stored in the second compressed air reservoir 22 can be guided into the four air springs 18 via the reservoir line 34 and the supply line 26. The vehicle body can be lifted. The compressor 12 is designed as a scroll compressor 36.

Another embodiment of the method according to the invention is schematically shown in fig. 15. The level control system used for level control in fig. 15 corresponds to the level control system used for level control in fig. 14a to 14 c. Air from the atmosphere may be compressed by the compressor 12 and directed from the compression side 30 directly into the air spring 18 via the supply line 26 so that the vehicle body may be lifted.

Another embodiment of the method according to the invention is schematically shown in fig. 16. The level control system used for level control in fig. 16 corresponds to the level control system used for level control in fig. 14a to 14 c. To raise the vehicle body, compressed air from the first compressed air reservoir 20 is fed via a first pressure line 28 to the suction side 14 of the compressor 12 and is further compressed by the compressor 12. The recompressed compressed air is then fed into the air spring 18.

List of reference numerals

10. Level control system

12. Compressor with a compressor body having a rotor with a rotor shaft

12a first compression stage

12b second compression stage

14. Suction side

14a first suction chamber

14b second suction chamber

16. Atmospheric pipeline

18. Air spring

20. First compressed air reservoir

22. Second compressed air reservoir

24. Third compressed air reservoir

26. Supply pipeline

28. First pressure pipeline

30. Compression side

30a first compression chamber

30b second compression chamber

32. Second connecting valve

34. Reservoir pipeline

36. Scroll compressor having a rotor with a rotor shaft having a rotor shaft with a

38. Second connecting pipeline

40. Third connecting pipeline

42. Second pressure pipeline

44. Third connecting valve

46. First valve

48. Inlet valve

50. Check valve

52. Two-position two-way valve

54. Dryer

56. Air filter

58. Electric motor

60. Second valve

62. Switching valve

64. Decoupling valve

66. Discharge valve

68. Pressure sensor

70a, b, c storage valves for the first, second and third compressed air storages

72. Air spring valve

74. And a discharge line.

Claims

1. A level control system (10) for a vehicle by which a vehicle body is cushioned relative to at least one axle, comprising:

a compressor (12), wherein a suction side (14) of the compressor (12) is connected to the atmosphere via an atmospheric line (16),

at least one air spring (18) and at least one first compressed air reservoir (20) for a first pressure level, wherein the at least one air spring (18) and the first compressed air reservoir (20) are connected to a compression side (30) of the compressor (12) via a supply line (26),

At least one first pressure line (28) via which the first compressed air reservoir (20) can be connected to the suction side (14) of the compressor (12) via at least one first valve (46),

characterized in that at least one second compressed air reservoir (22) is provided for a second pressure level, which is higher than the first pressure level of the first compressed air reservoir (20), wherein the second compressed air reservoir (22) can be connected to the compression side (30) of the compressor (12) via the supply line (26), wherein the second compressed air reservoir (22) can be connected to the reservoir line (34) of the first compressed air reservoir (20) via at least one second connecting valve (32) via a second connecting line (38), so that the level control system (10) can be operated in cascade.

2. The level control system (10) according to claim 1, characterized in that at least one third compressed air reservoir (24) for a third pressure level is provided, which third pressure level is higher than the second pressure level of the second compressed air reservoir (22), wherein the third compressed air reservoir (24) is connectable to the compression side (30) of the compressor (12) via the supply line (26), wherein the second compressed air reservoir (22) is connectable to the suction side (14) of the compressor (12) via at least one second valve (60) via a second pressure line (42), and wherein the third compressed air reservoir (24) is connectable to the reservoir line (34) of the second compressed air reservoir (22) via at least one third connecting valve (44) via a third connecting line (40).

3. The level control system (10) according to claim 1 or 2, characterized in that the compressor (12) comprises at least a first compression stage (12 a) with a first suction chamber (14 a) and a first compression chamber (30 a) and a second compression stage (12 b) with a second suction chamber (14 b) and a second compression chamber (30 b), wherein the first suction chamber (14 a) is connected to the atmosphere by means of the atmospheric line (16), the first compression chamber (30 a) is connected to the second suction chamber (14 b), and the air spring (18), the first compressed air reservoir (20), the second compressed air reservoir (22) and preferably a third compressed air reservoir (24) are connected to the second compression chamber (30 b) of the second compression stage (12 b) via the supply line (26).

4. A level control system (10) according to claim 3, characterized in that the first compressed air reservoir (20) is connectable via the first valve (46) with a first suction chamber (14 a) of the first compression stage (12 a) and/or with a second suction chamber (14 b) of the second compression stage (12 b), wherein the first suction chamber (14 a) is connected to the atmosphere by means of the atmospheric line (16).

5. A level control system according to claims 2 and 3, characterized in that the second compressed air reservoir (22) is connectable via the second pressure line (42) with the first suction chamber (14 a) of the first compression stage (12 a) and/or with the second suction chamber (14 b) of the second compression stage (12 b) by means of the second valve (60).

6. The level control system (10) according to any one of the preceding claims, characterized in that the compressor (12), in particular the first and/or second compression stage (12 a, 12 b), is designed as a scroll compressor (36).

7. The level control system (10) according to any one of the preceding claims, characterized in that the second and/or third connection valve (32, 44) is designed as a check valve (50), whereby the compressed air can be blocked in a direction from the second and/or third compressed air reservoir (22, 24) to the first and/or second compressed air reservoir (20, 22).

8. The level control system (10) according to any one of the preceding claims, wherein the first valve (46) and the second valve (60) are designed as two-position two-way valves (52).

9. The level control system (10) according to any one of the preceding claims, wherein the first compressed air reservoir (20) has a larger storage volume than the second compressed air reservoir (22), and preferably the second compressed air reservoir (22) has a larger storage volume than the third compressed air reservoir (24).

10. Method for the horizontal control of a vehicle, by which the vehicle body is buffered with respect to at least one axle by means of a horizontal control system (10) according to any of the preceding claims, characterized in that compressed air is fed from the first compressed air reservoir (20) via the first valve (46) to the suction side (14) of the compressor (12) by means of the first pressure line (28), the pressure of which is increased by the compressor (12) and compressed air is fed to the second and/or third compressed air reservoirs (22, 24) via the supply line (26) and preferably via at least one storage valve (70 b, 70 c).

11. Method according to claim 10, characterized in that the first compressed air reservoir (20) is filled to at least a first pressure level by sucking in air which enters from the atmosphere and is compressed by a compressor (12) with the storage valve (70 a) of the first compressed air reservoir (20) open.

12. Method according to claim 10 or 11, characterized in that the second compressed air reservoir (22) is filled to at least a second pressure level by sucking air that is led from the atmosphere into or from the first compressed air reservoir (20) back to the suction side (14, 14a, 14 b) and compressed by the compressor (12) with the second connection valve (32) closed and the storage valve (70 b) of the second compressed air reservoir (22) open.

13. Method according to any of the preceding claims 10 to 12, characterized in that the third compressed air reservoir (24) is filled to at least a third pressure level by sucking air that enters from the atmosphere or is led back from the first and/or second compressed air reservoir (20, 22) to the suction side (14, 14a, 14 b) and is compressed by the compressor (12) with the third connection valve (44) closed and the storage valve (70 c) of the third compressed air reservoir (24) opened.

14. Method according to any of the preceding claims 10 to 13, characterized in that the vehicle body is lifted by means of an air spring (18) such that compressed air from the second and/or third compressed air reservoir (22, 24) is introduced into the air spring (18).

15. Method according to any one of the preceding claims 10 to 14, characterized in that, for lifting the vehicle body, compressed air from the first or second compressed air reservoir (20, 22) which is fed via the first pressure line (28) and/or the second pressure line (42) to the suction side (14, 14a, 14 b) of the compressor (12) and is further compressed by the compressor (12) is introduced into the air spring (18).

16. Method according to any of the preceding claims 10 to 15, characterized in that, for lifting the vehicle body, compressed air is fed from the compression side (30) of the compressor (12) directly to the air spring (18) via the supply line (26).