Patent Application
20130247553
Air suspension installation, pneumatic system and vehicle comprising an air suspension installation, and method for operating a pneumatic installation of the air suspension installation.
The invention generally relates to an air suspension installation for a vehicle according to the preamble of Claim 1. The invention also relates to a vehicle, such as a private vehicle or a commercial vehicle having at least two axles and having an air suspension installation according to Claim 13. The invention further relates to a method according to the preamble of Claim 14.
A pneumatic system of the general type under consideration, e.g. disclosed in EP 1 165 333 B2 is used in vehicles of all types. A pneumatic system of this type is used for the suspension and potentially also for level control in a vehicle, so that the distance between the axle of the vehicle and body of the vehicle can be adjusted. An air suspension installation of such type comprises a plurality of bellows, each acting as a pressure chamber for a pneumatic spring, which raises the body of the vehicle with increasing filling and can lower it with decreasing pressurization. With increasing distance between the axle of the vehicle and the body of the vehicle or ground clearance, the spring travels can be longer and more uneven surfaces can also be overcome without this leading to contact with the body of the vehicle. Such pneumatic systems are used in off-road vehicles and sport utility vehicles (SUV). Especially with SUVs with very powerful engines, it is desirable that the vehicle is provided with relatively little ground clearance on the one hand for high speeds on the road and on the other hand with a relatively large ground clearance for off-road. It is further desirable to carry out a change of the ground clearance as rapidly as possible, which increases the requirement for speed, flexibility and reliability of a pneumatic system having an air suspension installation.
A compressed air supply system typically supplies the above-mentioned air suspension system in a pneumatic system with compressed air from a compressed air supply, for example in the region of a pressure level of 5 to 20 bar. The compressed air is supplied by an air compressor of a pressure source. For supplying the air suspension installation, the pressure source is connected to a connection of a pneumatic line of the air suspension installation, which can also be pneumatically connected to a vent. The compressed air supply installation and the air suspension installation can be vented by blowing off air via a venting valve apparatus. A pneumatic supply line of the compressed air supply installation usually comprises an air dryer in order to ensure long-term operation of the compressed air supply installation or to prevent the collection of moisture in the pneumatic system.
A controllable control valve in the form of a solenoid valve—also referred to as a switching valve—is usually connected upstream of each air bellows of the air suspension installation. A controllable control valve is connected to the pneumatic line of the air suspension installation in such a way that the air bellows can be filled or emptied—depending on a switching state of the controllable control valve. In other words, air masses can be adjusted in an air bellows in order to thereby regulate the suspension characteristics or the level for a vehicle.
It is desirable to design an air suspension installation of the above-mentioned type not only with respect to the increasing requirement for speed, flexibility and reliability, but in addition—without having to make restrictions of a functional nature—as simply as possible.
The invention is based on this point, its object being to specify an air suspension installation and a pneumatic system as well as a vehicle and a method, with which the pneumatics of the air suspension installation are simplified. In particular, the simplification should take place in such a way that relatively simplified control of the air suspension installation is achieved. This should especially be achievable without functional restriction of the air suspension installation or of the pneumatic system. In particular, the functionality of an air suspension installation should be increased with respect to speed, flexibility and reliability.
Concerning the air suspension installation, the object is achieved by the invention by means of an air suspension installation of the above-mentioned type, with which according to the invention the features of the characterizing part of Claim 1 are provided.
The air suspension installation for a vehicle having a pneumatic installation provided for operation with a compressed air supply installation comprises:
The invention is based on the consideration that a switching valve is connected upstream of an air bellows of the air suspension installation that is used as a pressure chamber for a pneumatic spring, namely via a controllable control valve in the form of a solenoid valve for controlling an air mass in the air bellows. In particular, each air bellows has an associated control valve for reasons of functional safety. Each of the control valves could in principle be connected by means of a separate control line to a controller and could be separately controlled or monitored. However, the invention has recognized that it is possible, without restrictions on functional safety, to assign a control valve to each air bellows and yet to provide simplifications with respect to the controller. For this purpose the invention surprisingly provides for the formation of a first and a second control valve as a controllable solenoid valve assembly, wherein the first control valve forms a primary valve and the second control valve forms a secondary valve of the solenoid valve assembly. The solenoid valve assembly advantageously comprises a pneumatic part that can be actuated by a magnetic part. Depending on the switching state of the primary valve and of the secondary valve, a first and a second air bellows associated with the solenoid valve assembly can be filled or vented. Said combination of a first and second control valve in a solenoid valve assembly forms, according to the recognition of the invention, the basis for the simplification of a pneumatic means and of the controller of the first and second control valves. According to the invention, it is also provided that the primary valve and the secondary valve can be controlled by a control means of the solenoid valve assembly, especially of the magnetic part, common to both and acting on both. It has surprisingly been shown that with a control means provided according to the invention acting on both—primary valve and secondary valve—the same can be electronically controlled simultaneously or sequentially. In particular, however, the number of control valves associated with the air bellows [e.g. four for a four-wheel vehicle] can be combined into groups of [e.g. two] solenoid valve assemblies, each having a primary valve and a secondary valve.
With the concept of the invention, costs and risks of failure of an air suspension installation can be reduced. Said advantage is primarily due to the fact that because of the provided jointly acting control means of the magnetic part of the solenoid valve, assembly interfaces, lines and final control stages are omitted, which are provided separately for each control valve in the prior art. Moreover, connections in the cabling and the electronics can be omitted. In particular, moreover, the number of control means can be reduced, because at least the primary valve and the secondary valve can be controlled by a control means of the magnetic part of the solenoid valve assembly common to both and acting on both. In this way, the power consumption is significantly reduced, which likewise increases the reliability. Overall, the concept of the invention also leads to a smaller structural volume and reduced weight of an air suspension installation.
A pneumatic part of a solenoid valve assembly includes in particular the pneumatically operating parts, such as the valve with a valve body, valve seat, valve housing or similar. A magnetic part of a solenoid valve assembly includes in particular the electrically and/or magnetically working parts, such as actuating means and/or control means for the valve and coil, with a winding, armature, yoke and core as well as a control line or similar and the connections of the control line to the controller and coil.
The jointly acting control means according to the invention is in particular a magnetic part jointly acting on the primary and secondary valves, in particular a coil body, e.g. forming a dual armature solenoid valve or a common control line.
In particularly preferred developments of the concept of the invention it is provided to connect the primary valve and secondary valve of the solenoid valve assembly either in parallel or in series. The primary valve and secondary valve should be normally closed.
In principle however, a normally open variant is not excluded. All four variants can be combined with each other in any way. A series arrangement of the primary and secondary valves is suitable for a particularly flexibly configurable, time-sequential switching sequence of primary and secondary valves. A parallel arrangement of the primary and secondary valves is particularly suitable for the simultaneous switching of primary and secondary valves. Each primary and/or secondary valve is preferably in the form of a 2/2-way valve. A series arrangement of the primary and secondary valves is particularly suitable for the sequential switching of primary and secondary valves. The primary valve is preferably in the form of a 2/2-way valve or the secondary valve is preferably in the form of a 3/2-way valve.
The concept of the invention also leads to a vehicle as claimed in claim 13 having an air suspension installation according to the concept of the invention as well as having a compressed air supply installation. The compressed air supply installation preferably comprises a pressure source, a venting means and a pneumatic supply line connected to the connection of the pneumatic line, into which an air dryer is connected. The concept of the invention also leads to a method according to the invention as claimed in claim 14.
Other advantageous developments of the inventions are disclosed in the dependent claims and specify in detail advantageous options for implementing the concept explained above in the context of the object as well as with respect to other advantages.
In the context of a particularly preferred development of the invention it is provided—as mentioned above—that the common magnetic part acting on the primary valve and the secondary valve comprises a common coil body acting on the primary and secondary valves as a common control means. This has the advantage that a separate coil body for each of the control valves can be omitted. The development provides that for each solenoid valve assembly only a single coil body is provided as a common control means jointly acting on the primary and secondary valves. Advantageously, practically half of all otherwise necessary coil bodies are omitted, which means a significant reduction in weight and control costs. In particular, in the context of said development it is provided that the solenoid valve assembly is in the form of a dual armature solenoid valve. A dual armature solenoid valve preferably comprises a primary armature carrying a first seal element of the primary valve and secondary armature carrying a second seal element of the secondary valve, which are disposed in a common coil body as a common control means. The primary armature has an associated primary valve seat and the secondary armature has an associated secondary valve seat here. The basic functionality of a conventional dual armature solenoid valve can be found e.g. in the applicant's DE 35 01 708 A1, whose contents are hereby incorporated by reference in the contents of the disclosure of the present application.
In the context of a particularly preferred development it is provided that the pneumatic installation comprises a gallery line, which is connected to the pneumatic line. A gallery line is in particular understood to be a pneumatic distribution line, from which at least two branch lines emanate. In particular, an air bellows is connected to a branch line that is connected to the gallery line. The design of the pneumatic installation with a pneumatic line for connection to the compressed air supply installation as well as a gallery line and branch lines connected thereto, each with at least one air bellows and at least one control valve—i.e. primary valve and/or secondary valve—has shown itself to be particularly effective with regard to dynamics and the manner of operation.
Advantageously, the pneumatic installation comprises at least one other pressure chamber, e.g. in the form of a compressed air reservoir, a pressure sensor or similar. In particular, such a pressure chamber can be connected to the pneumatic line via a further controllable control valve in the form of a solenoid valve in such a way that the pressure chamber—depending on a switching state of the controllable control valve—can be filled or vented. It has proven to be particularly preferable that the other control valve part is also part of a solenoid valve assembly according to the concept of the invention, i.e. is part of a solenoid valve assembly in the form of a primary valve or a secondary valve.
In the context of the developing concept of a pneumatic installation with a pneumatic line, gallery line and branch lines, it has been found to be particularly advantageous that the primary valve and/or secondary valve is connected to at least one branch line to the pneumatic line, advantageously via the gallery line. In particular, it is advantageously provided that a bellows-side pneumatic connection of the primary valve is connected to a first branch line and a bellows-side pneumatic connection of the secondary valve is connected to a second branch line. The first and second branch lines are advantageously separate branch lines, each comprising an air bellows. This ensures that at least one control valve, namely the primary valve and/or the secondary valve, is disposed upstream of each air bellows. A pressure sensor can also be connected to the gallery line directly or via a branch line.
A pressure limiter advantageously holds a pneumatic connection sealed up to a relatively high limiting pressure and only opens it at a relatively high limiting pressure.
The invention also results in a vehicle having at least two axles, wherein the first and second air bellows are disposed on one of the two axles to form a pneumatic spring in each case. Such a vehicle can, e.g., be a private vehicle, in particular an SUV (Sport Utility Vehicle) as already mentioned. The concept of the invention has also proved particularly useful in a commercial vehicle.
In the context of particularly preferred developments, a vehicle can comprise a single-axle air suspension that follows the concept of the invention. In other words, for a single axle of the vehicle, a solenoid valve assembly according to the concept of the invention is provided with a primary valve and a secondary valve. These can be controlled by mean s of a control means of the magnetic part of the solenoid valve assembly common to both and acting on both.
In the context of a development, it is also possible to provide another axle of the vehicle with a solenoid valve assembly according to the invention. In particular it is also provided that in addition to the first axle at least one second axle of the vehicle also comprises a further solenoid valve assembly equally according to the concept of the invention, i.e. with a third and a fourth air bellows, with which a primary valve and a secondary valve according to the further solenoid valve assembly are associated.
So-called average value control leads to a pressure being set for the first and second air bellows associated with an axle of a vehicle according to an average value of the pressure in the first and second air bellows. With so-called left-right control a separate pressure setting results in a pressure in the first and second air bellows being separately adjustable.
The concept of the invention also comprises developments with which average value control is provided for only one or both or a plurality of, possibly all axles. The concept of the invention also comprises a development with which left-right control is provided for one or both or a plurality of, possibly all axles. The concept of the invention also comprises a development with which average value control is provided for one of the axles and left-right control is provided for another axle. Depending on requirements, combinations of said developments can be implemented for specified operating states of a vehicle as well as for setting to work processes or special applications with more complex control technology.
In the context of the above-mentioned preferred first variant, it has been found to be advantageous that the primary valve and the secondary valve are disposed in a parallel circuit. Also advantageous are a gallery-side pneumatic connection of the primary valve to a first branch line and a gallery-side pneumatic connection of the secondary valve to a second—separate—branch line. The design of the solenoid valve assembly as a parallel circuit of control valves has proved particularly advantageous in the context of average value control, involving control to an average value of the pressure of the first and second air bellows. It has also been found to be relatively simple to control the primary and secondary valve with the same switching states. A corresponding controller is particularly advantageous that is designed to regulate the first and second air bellows pressure only according to an average value of the pressure of the first and second air bellows by specifying simultaneously identical switching states for the primary valve and secondary valve at all times. Such a controller has proved to be comparatively simple because it does not involve current control. For the case in which the primary valve and the secondary valve are associated with the two wheels of a single axle, in the context of said so-called average value control the axles are each controlled in relation to the average value of a pressure at the air bellows of the two wheels. As a result, the axle is thus controlled equally on the left and right.
A control arrangement can be particularly simply implemented with which only one axle of a vehicle is provided with air springs, which are controlled according to average value control of the above-mentioned type. This is preferably the front axle of a vehicle. The rear axle of a vehicle can e.g. be provided with conventional control valves.
In the context of a more sophisticated development—also within but not restricted to the context of the first variant—it has also been found to be advantageous to design the controller in such a way that a different pressure is controlled in the first and second air bellows. A controller developing the first variant also comprises in particular a current control module with which different switching states can be specified for the primary and secondary valves. Also this variation of a controller can preferably be implemented with a solenoid valve assembly forming a parallel circuit, i.e. in the context of the first variant.
By specifying different switching states of the primary and secondary valves, so-called right-left control can be achieved, with which a control valve assigned to the left wheel—e.g. the primary valve—and a control valve assigned to the right wheel—e.g. the secondary valve—are switched with different switching states, so that the associated air bellows can be subjected to different pressures.
Such left-right control can be achieved particularly simply based on a second variant of a solenoid valve assembly in a series circuit. It is preferably provided in the context of one development that the primary valve and secondary valve are disposed in a series circuit, wherein a gallery-side pneumatic connection of the primary and secondary valves of the solenoid valve assembly is connected to the same branch line.
In particular, at least one pneumatic line of the pneumatic installation comprises a residual pressure holding valve. Advantageously, at least one pneumatic line of the pneumatic installation—in particular the pneumatic line, the gallery line or a branch line—can comprise a residual pressure holding valve and/or a pressure limiter. It is advantageous for certain requirements to hold a residual pressure in the system. This can prevent a collapse of air bellows in an air suspension installation. A pressure limiter has the advantage that the pneumatic installation is protected against an excessive pressure loading.
The concept of the invention also leads to a method according to claim 16. In particular, with the method, it is provided in the context of one development that the primary valve and the secondary valve of the solenoid valve assembly are designed to be activated time-sequentially in a first operating mode with a control current rising above a current amplitude. It can also be provided that the control current at first only exceeds a current amplitude for activation of the primary valve and thereafter remains in a range that only keeps the primary valve activated, while the secondary valve is not activated. At a later point in time, the control current can exceed a second current amplitude, which is sufficient to also activate the secondary valve. Thereafter, the control current can have a current amplitude that is sufficient to keep both the primary valve and also the secondary valve in the activated state. For deactivation of the secondary valve and the primary valve, a control current can be reduced below the mentioned current amplitudes, possibly with a known hysteresis. In a second operating mode the control current can rise comparatively rapidly to a current amplitude that lies above a current amplitude that is sufficient to activate the primary valve and the secondary valve simultaneously. For this the current amplitude should lie above the highest current amplitude for activation of the primary valve and the secondary valve.
Activation of the primary valve and/or the secondary valve can take place for blowing off air or for delivering air to an air bellows. The air can be passed as an air flow via the pneumatic line. Activation of a primary or secondary valve can e.g. take place according to a ride height control of the vehicle. For instance, air mass control connected to ride height control can also be provided, which controls a volumetric flow through the pneumatic line. Activation of the primary valve and/or the secondary valve can take place under time control. Time control is recommended, e.g. if a ride height display is too noisy. Time-controlled activation of the primary valve and the secondary valve can e.g. also take place in the context of a regeneration cycle for the compressed air supply installation.
Example embodiments of the invention are now described below using the drawings. These do not necessarily represent the example embodiments to scale, but the drawing is rather carried out in a schematic and/or slightly distorted form where this is helpful for explanation. Reference is made to the relevant prior art in regard to supplements to information that can be directly learnt from the figure. Here it should be taken into account that various modifications and changes relating to the shape and the detail of an embodiment can be carried out without deviating from the general idea of the invention. The features of the invention disclosed in the description, in the drawing as well as in the claims can be significant for the development of the invention both individually and also in any combination. Moreover, all combinations of at least two features disclosed in the description, the drawing and/or the claims fall within the scope of the invention. The general idea of the invention is not restricted to the exact form or the detail of the preferred embodiment shown and described below or restricted to an object, which would be restricted in comparison to the object claimed in the claims. For the specified ranges of dimensions, values lying within the limits mentioned are disclosed as limit values and can be used and claimed as desired.
Other advantages, features and details of the invention will become apparent from the following description of the preferred example embodiments and using the drawing; in the drawings:
The vehicle 100 can be, e.g., a private vehicle such as an SUV or similar or a commercial vehicle. A first axle A1 with two wheels R1 and R2 and a second axle A2 with two wheels R3 and R4 of the vehicle 100 are symbolically illustrated here. The air suspension installation 110 of
In the present case the air suspension installation 110 comprises a first and a second solenoid valve assembly 120, 130 in an embodiment according to the concept of the invention. The air suspension installation 110 for a two-axle vehicle 100, i.e. with a first axle A1 and a second axle A2, is provided with four control valves 11, 13, 18, 19, each of which is disposed upstream of a respective air bellows 43, 45, 46, 47, thereby forming a pneumatic spring. Each of the control valves 11, 13, 18, 19 is formed in the present case as a controllable 2/2-way valve, namely as a solenoid valve. Using the control valves 11, 13, 18, 19, air masses in the four air bellows 43, 45, 46, 47 can be regulated. As can be seen symbolically in
In the present case the first control valve 11 forms a primary valve and the second control valve 13 forms a secondary valve of the solenoid valve assembly 120. The other first control valve 18 forms a primary valve and the other second control valve 19 forms a secondary valve of the other solenoid valve assembly 130. A primary valve of a solenoid valve assembly is referred to throughout below by “I”. A secondary valve of a solenoid valve assembly is referred to throughout below by “II”. In the illustrations of the switching states of
The control unit 1, e.g. an electronic control unit ECU, is connected via control lines 5, 6 to a coil body 14, 7 forming the magnetic part of a solenoid valve assembly 120, 130 in each case. That is to say, the control unit 1 is designed to carry out an actuation of the first control valves 11, 18 and second control valves 13, 19 in each case in such a way that a primary valve I and a secondary valve II—denoted in more detail in FIG. 2—of one of the solenoid valve assemblies 120, 130 are to be controlled via the control lines 5, 6 and coil bodies 14, 7. Here, the control lines 5, 6 and coil bodies 14, 7 each form the control means common to both and acting on both the primary valve I and the secondary valve II. The coil body 7—as shown above the connections 8, 9—is an essential component of the magnetic part of the control valves 11, 13 and is coupled thereto. The coil body 14—as shown above the connections 16, 17, which are connected to each other—is an essential part of the magnetic part of the control valves 18, 19 and is coupled thereto. In the present case each solenoid valve assembly 120, 130 is also in the form of a conventional dual-armature solenoid valve that is not shown in detail. A dual-armature solenoid valve also comprises in detail a primary armature supporting a first seal element of the primary valve I (one of the first control valves 11, 18) and a secondary armature supporting a second seal element of the secondary valve II (one of the second control valves 13, 19), which are disposed in an above-mentioned common coil body 14, 7. Here, the primary armature is associated with a primary valve seat and the secondary armature is associated with a secondary valve seat.
Moreover, another coil body 21 of another control valve 22 in the form of a solenoid valve can be controlled via a control line 4 by the control unit 1 in order to selectively connect a compressed air reservoir 51 via the gallery line 12 to the compressed air supply installation 2 or to decouple it from the same.
The other connections of the coil body 7, 14, 21 are each connected via individual control lines, e.g. 10, 15, to a common control line 23 and via the same to the control unit 1, wherein the common control line 23 can be set by the control unit 1 to a common potential, e.g. reference potential, null potential or supply voltage potential.
A compressed air supply installation 2 can e.g. be a simple compressed air container or in the present case a compressed air supply installation 2 that is not shown in detail, comprising a pressure source, a venting means and a pneumatic supply line having an air dryer and connected to the connection of the pneumatic line 3. A gallery line 12 forming a compressed air distribution line is first connected to the pneumatic line 3 in the present case. A respective gallery-side compressed air connection of the control valves 11, 13, 18, 19 is connected to the gallery line 12 via branch lines 350, 360, 370, 380.
In the embodiment of FIG. 1—as will be explained in detail using
For measurement of the pressure in the supply line 3 and the gallery line 12 a pressure sensor 26 is provided, which is connected via a compressed air line 20 to the gallery line 12 for pressure measurement and via electrical control lines 24, 25 to the control unit 1. The voltage supply for the pressure sensor 26 from the control unit 1 and the signal return to the control unit 1 can take place via the electrical control lines 24, 25. Alternatively, a separate third electrical control line (not shown) for the signal return to the control unit 1 can also be provided. The pressure sensor 26 converts the measured air pressure into an electrical signal that can be delivered via the control lines 24, 25 to the control unit 1 and is evaluated by the same for system control purposes.
With the example embodiment shown in
With the example embodiment shown in
According to the embodiment of
This enables so-called average value control to be achieved—preferably in the context of a switching state shown in
The 2/2-way valves 11, 13, 18, 19 in
In an embodiment that is not shown here, at least one of the first or second axles A1, A2 can be implemented with an individual control building on the embodiment according to
With the example embodiment shown in further detail in
The solenoid valve assembly 120 is connected to the pneumatic line 3 via the gallery line 12 and via at least one branch line 350, 360, wherein a bellows-side pneumatic connection Y1 of the primary valve I is connected to a first branch line 35 and a bellows-side pneumatic connection Y2 of the secondary valve II is connected to a second branch line 36, wherein the first branch line 35 and the second branch line 36 are separate branch lines. The primary valve I and the secondary valve II are disposed in a parallel circuit, wherein a gallery-side pneumatic connection X1 of the primary valve I is connected to a first branch line 350 and a gallery-side pneumatic connection X2 of the secondary valve II is connected to a second branch line 360—in the present case the first branch line 350 and the second branch line 360 are separately connected to the gallery line 12. 10. A control unit 1 is formed to regulate the pressure in the first and second air bellows 43, 45 according to an average value of the pressure of the first and second air bellows—also identical switching states can be specified for the primary and secondary valves I, II of the pneumatic parallel circuit in the solenoid valve assembly 120.
A first state is shown in
In the second state shown in
In the third state shown in
In the fourth state shown in
With the example embodiment according to
In order to achieve the state according to
By means of the states shown in
Another example embodiment according to a second variant is shown in FIG. 3—again the control valves 61, 64 shown there, also referred to as a primary valve 61 and a secondary valve 64, each form a solenoid valve assembly 120′ or 130′. These could be used e.g. instead of the solenoid valve assembly 120 or 130 of the embodiment of
In the present case a coil body 60—as with the embodiment of FIG. 1—of primary valve I (control valve 61) and secondary valve II (control valve 64) is also used as a common coil body 60 acting on both for controlling the switching states thereof. The coil body 60 of
The solenoid valve assembly 120′, 130′ is connected to the pneumatic line 3 via the gallery line 12 by means of at least one branch line 600, wherein a pneumatic bellows-side connection Y1 of the primary valve I is connected into a first branch line 600 and a pneumatic bellows-side connection Y2a, Y2b of the secondary valve II is connected into a second branch line 62, 63, wherein the first branch line 600 and the second branch line 62, 63 are separate branch lines. The primary valve I and the secondary valve II are disposed in a series circuit, wherein a gallery-side pneumatic connection X1, X2 of the primary valve I and secondary valve II of the solenoid valve assembly 120′, 130′ is connected to the same branch line 600. In the present case, said branch line 600 is connected as a single branch line 600 to the gallery line 12. A control unit 1 is designed to control a different pressure in the first and second air bellows 65, 66. In particular, different switching states can be specified for the primary and secondary valves I, II of a pneumatic series circuit in a solenoid valve assembly 120′, 130′.
The embodiment shown in
With such an embodiment, the components 60 through 66 shown in
In a modified embodiment of the invention it is also possible to combine a solenoid valve assembly as described above as a dual-armature solenoid valve for an axle having a pneumatic parallel circuit of primary and secondary valves with optional average value control—for example in the embodiment of
By the use of a dual-armature solenoid valve or a different solenoid valve assembly according to the concept of the invention having a primary valve I and a secondary valve II, e.g. in a parallel circuit or a series circuit, in principle a coil body can be saved, whereby the costs of the vehicle cabling and the electronic control unit are reduced.
The solenoid valve assembly 120, 13, 120′130′ can, but does not have to, e.g. be p0rovided in each case as a dual-armature valve with a coil body 7, 14, 60, by whose energization the respective armature is operated in a controlled manner and hence controlled switch positions of the two control valves can be set. Such a dual armature solenoid valve can e.g. comprise two magnet armatures (primary armature and secondary armature) disposed in a common or separate armature guide assembly and optionally each loaded by a spring, which can be selectively or jointly operated by a common coil body. With the coil body not energized, the two armatures can each be in their basic positions, e.g. determined by the spring loading, while, when supplied with suitable currents in the coil body, the first and/or second armatures can be activated and changed into the other control valve switch position. Using current control, these switch positions can be specified and achieved in a controlled manner.
The graph of
On exceeding a first current amplitude SA1 the primary valve I changes from a normally closed state into an opened switching state because of the setting of a control valve spring of the primary valve I (e.g. first control valves 11, 18 of
On exceeding a second, in the present case higher, current amplitude SA2, the secondary valve II also switches (e.g. second control valves 13, 19 of
In principle in a modified embodiment the de-energized and energized switching states can also be exactly selected oppositely; i.e. the primary and/or the secondary valve can be designed for a normally open and closed when energized switching state.
In the present case—with the primary and secondary valves I, II designed to be normally closed—when reducing the control current amplitude the primary valve closes again, taking into account a certain hysteresis, when the current falls below a third current amplitude SA3, i.e. the primary valve now changes from the energized open state into an again closed switching state occurring at lower current. In this switching state of a solenoid valve assembly the primary valve I is closed and the secondary valve II is open (e.g.
On reducing below a fourth, in the present case lower current amplitude SA4, finally the secondary valve II changes from the energized open switching state back into the de-energized closed switching state. A corresponding control current module can be provided in a control unit 1 in order to define switching states SA1 through SA4.
The above-mentioned switching sequence results independently from a series or parallel circuit of a solenoid valve assembly 120, 130 or 120′, 130′. However, in contrast to the above-mentioned examples of a parallel circuit of primary and secondary valves I, II in a solenoid valve assembly 120, 130 of
With a series circuit of the primary and secondary valves I, II in a solenoid valve assembly 120′, 130′, with the primary valve closed (prior to exceeding the current amplitude SA1 and after reducing below the current amplitude SA3) none of the air bellows is connected to the gallery line 12 (
With a series circuit of primary and secondary valves I, II in a solenoid valve assembly 120′, 130′, with the primary valve open (after exceeding the current amplitude SA1 and prior to reducing below the cur rent amplitude SA3) either the air bellows 65 or the air bellows 66 is connected to the gallery line. Prior to exceeding the current amplitude SA2 the air bellows 66 is connected to the gallery line (
The switching currents of the individual switching stages can be adjusted in individual learning steps. Learning of the thus described current amplitudes SA1, SA2, SA3, SA4 as relevant switching points for an on/off switching state transition of the primary valve I (e.g. first control valves 11, 18 of
As a result it is to be determined that for an initial pressure rise the current amplitude SA1 of the primary valve is reached, i.e. the primary valve is opened and connects the corresponding branch line to the corresponding air bellows, which can be recorded from the initial pressure increase.
As a result the current amplitude SA3 of the primary valve I is reached if the pressure does not reduce further. A pressure that does not reduce further is the result of the primary valve I changing from the open switching state into the closed switching state. The current amplitudes SA1, SA3 of the switching currents of the primary valve are determined by 4. and 7.
The current amplitude SA4 does not have to be explicitly determined, because the closure of the primary and secondary valves I, II can be achieved simply by turning off the current amplitude SA. The current amplitudes SA1 through SA4 for switching points exactly determinable in this way can be used for the further optimized functional operation of the primary valve and secondary valve.
In summary, the invention relates to an air suspension installation 110 for a vehicle 100 having a pneumatic installation 200 designed for operation with a compressed air supply installation 2, which comprises:
| Number | Date | Country | Kind |
|---|---|---|---|
| 102010054703.4 | Dec 2010 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP11/05861 | 11/22/2011 | WO | 00 | 6/5/2013 |
