Component in a compressed air system of a vehicle

Abstract

A component in a compressed air system of a vehicle is provided, which component is provided with air suspension. The component is designed to lift the vehicle body by filling at least one air spring, a solenoid valve being switchable in cooperation with an electronic control device, the component comprising a pressure line for filling the air spring, and the pressure line comprising a first branch line, which is connectable to the pressure line via a pilot-controlled solenoid valve for filling the air spring, and the first branch line comprising a first supply line for each air spring and a pilot-controlled solenoid valve, and a second branch line for providing control pressure, the second branch line comprising a second supply line for the pilot-controlled solenoid valve, wherein the second branch line is connected to the pressure line via a non-return valve, which provides a blocked position to prevent the occurrence of exhaust or pressure drop in the second branch line.

Description

TECHNICAL FIELD

[0001] The invention relates to a component in a compressed air system of a vehicle provided with air suspension, the vehicle being equipped with air springs, which component is designed to lift the vehicle body horizontally relative to the road surface by pressure-charging at least one air spring, i.e. by filling at least one air spring with compressed air. BACKGROUND

[0002] In vehicles in which the necessary devices are operated by means of a compressed air system, it is important to ensure the functionality of the systems operated by compressed air in all operating states and in the event of potential air pressure fluctuations. Therefore, a number of safety systems are usually provided which ensure the functionality of the systems even in extreme cases. In particular in commercial vehicles or buses, in which not only the brake system is operated by compressed air, but also the air springs need to be supplied with compressed air, it is important, on the one hand, to maintain the brake function first and foremost, while on the other hand it is also important to ensure the safe suspension of the vehicle, thus avoiding critical driving conditions.

[0003] It is particularly important that the vehicle has only one single air supply system, which includes one on-board compressor. Usually, the pneumatic circuit of such a system, in which the brake circuit and the air springs are supplied by only one pressure source, has to be designed in such a way that the brake system is prioritized over the other components operated by compressed air. Nevertheless, it is equally important to maintain the pneumatic circuit for operating the levelling system equipped with air springs under conditions in which the vehicle can still be lifted or lowered and thus the safe driving operation is still ensured. This coordinated operation can be achieved by means of control / regulation by means of electric or pneumatic components, for example by means of control valves responsive to pressure changes and / or by means of an electronic circuit providing the corresponding logic by means of signals from pressure sensors.

[0004] However, even in the event of a system-inherent air pressure fluctuation which can be expected without the need to activate a safety position or a failsafe position, if this is not necessary, all functions should be switchable and executable in all common operating states and situations within the compressed air system. Therefore, in this context, it is necessary to ensure that the control / regulation system does not perform unnecessary blockings or deactivations of the auxiliary devices even in the event of unusual switching operations or air consumption.

[0005] Such a process can occur, for example, when a sudden lifting of the vehicle body from a very low initial position by a sudden filling of the air springs in the levelling system is performed, for example, when a rapid lifting from the resting position of the vehicle body on the support or emergency springs (rapid lifting from the bumper) is performed.

[0006] This rapid and forceful lifting requires a large amount of air and therefore of course a very high air consumption. However, the amount of air that has to be filled into the bellows of the air spring to lift the chassis can cause a pressure drop in the remaining system or in other pipeline sections of the compressed air system. Since the pressure in the entire system is of course monitored by pressure sensors, a detection of such a pressure drop can lead to signals of the pressure sensors for the control system. These signals can cause reactions in the control logic that can be undesirable or even unwanted, for example, can lead to an unwanted deactivation of certain system components or functions.

[0007] In particular, this can become critical at times when such a sudden pressure drop caused by a lifting operation, when those compressed air pipelines that are set up to supply a pilot-controlled solenoid valve with a pilot pressure are affected. In the event of such a pressure drop in a pilot pressure pipeline triggered by a signal from a corresponding pressure sensor, it can be necessary at that time to switch the pilot-controlled solenoid valve by the control logic into a state that is itself safe and predetermined. However, without a sufficiently high pilot pressure, this state cannot be safely reached anymore. In theory, this situation can then lead to the pilot-controlled solenoid valve being in an irrelevant position. In the worst case, this irrelevant position can accelerate a further pressure drop.

[0008] Of course, this influence can be prevented by providing a sufficient reservoir with a high capacity in the compressed air system, which in this case compensates for the pressure drop in the pipeline sections, in particular in the pilot pressure pipeline sections, and which can prevent the pilot-controlled solenoid valve from being in an irrelevant position due to a signal response of the control system. However, integrating an additional reservoir is not only expensive, but also increases the size of the entire system and its complexity. Therefore, in smaller and lighter vehicles, integrating an additional reservoir is not a particularly preferred option for the design engineer. SUMMARY

[0009] Against this background, it is the object of the present application to design a compressed air system for a vehicle provided with air suspension and air springs, so that a lifting of the vehicle body or vehicle frame relative to the road surface by rapid filling of the air springs can be achieved in a simple manner without the above-mentioned switching problems and without the occurrence of irrelevant valve positions of pilot-controlled solenoid valves due to pressure drops in the individual system components. Furthermore, the use of additional components, such as additional reservoirs, should be avoided, since these components would significantly change the size of the compressed air system or lead to an uneconomical design and production of the compressed air system.

[0010] This object is achieved by a component in a compressed air system of a vehicle having the features of the invention.

[0011] The component according to the invention comprises a pneumatic circuit which is provided with pilot-controlled solenoid valves, wherein the solenoid valves are switchable in cooperation with an electronic control device (ECU = electronic control unit), and a pressure line which is connected to a compressed air source provided in the vehicle for filling air springs, wherein the pressure line comprises branch lines, namely a) a first branch line for filling air springs, which first branch line comprises a first supply line for each air spring, and b) a second branch line for providing a pilot pressure to the pilot-controlled solenoid valves, which second branch line comprises a second supply line for the pilot-controlled solenoid valves, wherein in the first branch line the first supply line for each air spring comprises a pilot-controlled solenoid valve, respectively, which has a gate and a blocking position, wherein the first branch line is connectable to the pressure line via the pilot-controlled solenoid valve, and the solenoid valve has a first gate position for filling the air spring and a second gate position for venting the first branch line, and wherein the second branch line is connected to the pressure line via a non-return valve which provides a blocking position to prevent venting or a pressure drop in the second branch line.

[0012] With such a configuration of the component, when a sudden, rapid lifting of the chassis takes place by filling a large amount of air into the air springs and by connecting the first branch line to the pressure line via the pilot-controlled solenoid valve, the non-return valve in the second branch line prevents the pilot pressure line from losing pressure when filling the air springs. The solenoid valve in the first branch line occupies the first gate position in order to fill the air spring during the filling process.

[0013] Here, the component is preferably configured as a module, i.e. as a separate, replaceable component which can be connected to the remaining components of the compressed air system. In the special field of air suspension development, such a component can also simply be denoted as a "leveling unit" or air suspension "valve module".

[0014] A further development of the invention is based on the first supply line for each air spring, which first supply line comprises a pilot-controlled 2 / 2-way solenoid valve, respectively. In this way, a very simple design of the pilot-controlled solenoid valve is used to fill the respective air spring. In appropriate cases, depending on the position of other valves in the circuit, the spring can also be vented in this way.

[0015] In another embodiment of the application, the first branch line can be connected to the pressure line via a pilot-controlled 3 / 2-way solenoid valve, a so-called "booster". Such a pilot-controlled solenoid valve is also a well-known and common series-produced valve, which can be used in various gate positions and thus for various switching operations in a simple manner.

[0016] Another configuration is based on a common central compressed air source for supplying the set air springs and the brake system. Due to the fact that the compressed air system comprises the assembly according to the application for lifting the vehicle body or the vehicle frame, it is possible to operate an even smaller system without additional separate reservoirs and to provide all safety functions even when the brakes and the level control system are operated by compressed air supplied from the same source. This is also particularly suitable for a configuration in which the central compressed air source is advantageously provided by only one single compressor in the vehicle.

[0017] Another embodiment is based on a non-return valve designed such that the control pressure is at least 5 bar. By setting the non-return valve to this pressure, the safety function of the pilot-controlled solenoid valve connected to the control line can be guaranteed, avoiding irrelevant positions such as intermediate positions.

[0018] Another configuration is based on the fact that the first branch line can be connected to the atmosphere via a silencer device when the pilot-controlled 3 / 2-way solenoid valve is switched to its second gate position. With such a circuit, the air spring can also be lowered at the time, which can be performed in a relatively soundless manner.

[0019] In a further development of the application, the pneumatic circuit and the electronic control device are integrated in an assembly / assembly-integrated component, and the electronic control device is connected to the vehicle control system via a connection component and / or a CAN bus. In this way, the magnet of the pilot-controlled valve can be centrally switched in cooperation with the electronic control device, and the magnet of the pilot-controlled valve can be integrated in the remaining switching logic in a simple manner. This means that the assembly is designed as a modular component that matches the components of the compressed air system, preferably as a separate and exchangeable component.

[0020] Advantageously, the compressed air system equipped with the assembly according to the application is suitable for smaller commercial vehicles or for motorbuses that rely on space-saving and weight-reducing components.

[0021] In summary, the application provides an assembly in a compressed air system of a vehicle, which is provided with an air suspension, which is equipped with air springs, which is designed to lift the vehicle body relative to the road surface by pressure-charging at least one air spring,

[0022] The assembly comprises a pneumatic circuit provided with first, second and third pilot-controlled solenoid valves which can be switched in cooperation with an electronic control device,

[0023] The assembly comprises the following devices:

[0024] a pressure line for filling the air springs, which pressure line is connected to a compressed air source,

[0025] The pressure line comprises a plurality of branch lines, namely

[0026] a) a first branch line for filling the air springs, which first branch line comprises a first supply pipe for each of the air springs,

[0027] b) a second branch line for providing a pilot pressure to the first, second and third pilot-controlled solenoid valves, which second branch line comprises a second supply pipe for the first, second and third pilot-controlled solenoid valves,

[0028] wherein in the first branch line (8) the first supply pipe for each air spring comprises a second and a third pilot-controlled solenoid valve, respectively, with a gate and a blocking position,

[0029] wherein the first branch line can be connected to the pressure line via a pneumatically pressure-controlled first pilot-controlled solenoid valve, and the first pilot-controlled solenoid valve has a first gate position for filling the air springs and a second gate position for venting the first branch line,

[0030] wherein the second branch line is connected to the pressure line via a non-return valve which provides a blocking position to prevent venting or pressure drop in the second branch line.

[0031] Furthermore, the invention also provides a compressed air system of an air-suspended vehicle, which is provided with the above-mentioned assembly, wherein the assembly is designed as a modular component which matches the components of the compressed air system.

[0032] Furthermore, the invention also provides an air-suspended commercial vehicle or motor bus which comprises the above-mentioned compressed air system. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 An assembly 1 according to the invention in a compressed air system is shown. With the assembly of the invention, it is possible to perform a horizontal lifting or raising of the vehicle body relative to the road surface by filling at least one air spring.Figure 1 Only in a purely schematic manner and by means of standard functional or circuit symbols. DETAILED DESCRIPTION

[0034] The assembly 1 comprises a pneumatic circuit 2 which is provided with pilot-controlled solenoid valves V1, V2 and V3 which can be switched in cooperation with an electronic control device 3. The assembly 1 is shown here in its outline which is indicated by dashed lines and comprises the necessary associated functional elements. Within the dashed outline of the assembly 1, the electronic control device 3 can also be seen, the outline of which is indicated by a dot-dash line. Within this dot-dash outline of the control device 3, inter alia, the functional elements for a pressure measuring sensor 4 and the insertion member 5 for the electrical connection 5.1 to the magnets of the pilot-controlled solenoid valves V1 to V3 can be found.

[0035] The pneumatic circuit of the assembly firstly comprises a pressure line 7 which is connected to a compressed air source 6 and provides the amount of compressed air for filling the air springs.

[0036] The pressure line 7 is divided into two branch lines, namely into a first branch line 8 for filling the air springs which comprises a first supply line 8.1 for each air spring and a second branch line 9 for providing control pressure which comprises a second supply line 9.1 for the pilot-controlled solenoid valves V1 to V3. The air springs themselves are not further shown here and are generally provided in a number corresponding to the number of suspension axles or wheels. Here, for the sake of simplicity, only the supply lines 8.1 for two air springs are shown. Of course, this number can be chosen as desired.

[0037] The first supply lines 8.1 associated with the first branch line 8 for each air spring comprise the pilot-controlled solenoid valves V2, V3, respectively, which can assume a gate or blocking position, respectively, depending on the switching of the solenoid valves. In this embodiment, the pilot-controlled solenoid valves V2 and V3 are 2 / 2-way solenoid valves, as is also apparent from the circuit symbol. For the sake of completeness, it should be mentioned here that the air springs can also be vented or lowered by means of these valves. The latter is dependent on the position of the pilot-controlled solenoid valve V1.

[0038] The pilot-controlled solenoid valve V1 is used here to connect the first branch line 8 to the pressure line 7. To this end, the solenoid valve V1 can assume a first gate position for filling the air springs and a second gate position for venting the first branch line 8, as is also apparent from the circuit symbol. In this embodiment, the pilot-controlled solenoid valve V1 is a 3 / 2-way solenoid valve. Here, venting of the first branch line 8 is carried out in a direct passage to the atmosphere via a silencer device 10.

[0039] According to the application, the second branch line 9 is connected to the pressure line 7 via a non-return valve 11. In the closed position of the non-return valve, the non-return valve prevents the second branch line 9 from being vented or from the pressure in the second branch line 9 falling, so that the pressure in the second branch line, i.e. the control pressure line, cannot fall below the minimum pressure of 5 bar.

[0040] In the upper part of Figure 1 two plug-in members or connections 12 and 13 can be seen, by means of which the assembly or its electronic control device can be connected to a vehicle control system not shown here and to a further sensor system of the vehicle or air suspension.

[0041] List of reference signs

[0042] 1 assembly in a compressed air system of a vehicle provided with an air suspension

[0043] 2 pneumatic circuit

[0044] 3 electronic control device

[0045] 4 pressure sensor

[0046] 5 plug-in member

[0047] 5.1 electrical connection

[0048] 6 compressed air source

[0049] 7 pressure line

[0050] 8 first branch line of the pressure line

[0051] 8.1 first supply pipe for the supply of air springs

[0052] 9 second branch line of the pressure line

[0053] 9.1 second supply pipe for the supply of pilot pressure

[0054] 10 silencer device

[0055] 11 non-return valve

[0056] 12 plug-in member and connection to a vehicle control system

[0057] 13 plug-in member and connection to a sensor system

[0058] V1 pilot-controlled 2 / 2-way solenoid valve

[0059] V2 pilot-controlled 2 / 2-way solenoid valve

[0060] V3 pilot-controlled 3 / 2-way solenoid valve.

Claims

1. A component (1) in a compressed air system of a vehicle, the vehicle being provided with air suspension and equipped with air springs, the component being designed to horizontally raise the vehicle body relative to the road surface by pressurizing at least one air spring. The component (1) includes a pneumatic circuit (2) equipped with first, second, and third pilot-controlled solenoid valves (V1, V2, V3), which can be switched in cooperation with an electronic control device (3). The component (1) includes the following means: A pressure line (7) is used to fill the air spring and is connected to a compressed air source (6). The pressure line (7) includes multiple branch lines, namely a) A first branch line (8) for filling the air springs, the first branch line (8) including a first supply pipe (8.1) for each of the air springs. b) A second branch line (9) for providing pilot pressure to the first, second and third pilot-controlled solenoid valves (V1, V2, V3), the second branch line (9) including a second supply line (9.1) for the first, second and third pilot-controlled solenoid valves (V1, V2, V3). in, In the first branch line (8), the first supply line (8.1) for each air spring includes a second and a third pilot-controlled solenoid valve (V2, V3) having a gate and a blocking position, respectively. The first branch line (8) can be connected to the pressure line (7) via a first pilot-controlled solenoid valve (V1) under pneumatic pressure control, and the first pilot-controlled solenoid valve (V1) has a first gate position for filling the air spring and a second gate position for venting the first branch line (8). The second branch line (9) is connected to the pressure line (7) via a check valve (11), which provides a blocking position to prevent venting or pressure drop in the second branch line (9).

2. The component according to claim 1, wherein, The second and third pilot-controlled solenoid valves (V2 and V3) are both pilot-controlled 2 / 2-way solenoid valves.

3. The component according to claim 1 or 2, wherein, The first pilot-controlled solenoid valve (V1) is a pilot-controlled 3 / 2-way solenoid valve.

4. The component according to claim 1 or 2, wherein, A central compressed air source is provided to supply air to the air springs and air braking system of the air suspension.

5. The component according to claim 4, wherein, The central compressed air source is provided by a compressor in the vehicle.

6. The component according to claim 1 or 2, wherein, The check valve (11) is designed such that the pilot pressure is at least 5 bar.

7. The component according to claim 3, wherein, When the pilot-controlled 3 / 2-way solenoid valve is switched to its second gate position, the first branch line (8) can be connected to the atmosphere via the silencer device (10).

8. The component according to claim 1 or 2, wherein, The pneumatic circuit (2) and the electronic control device (3) are integrated in the component, and the electronic control device (3) is connected to the vehicle control system via connecting parts (12, 13) and / or CAN bus.

9. A compressed air system for an air-suspended vehicle, comprising a component according to any one of claims 1 to 8, wherein, The component (1) is designed as a modular component that matches the components of the compressed air system.

10. The compressed air system according to claim 9, wherein, The component (1) is designed as a separate and replaceable part.

11. An air-suspension commercial vehicle or motor bus, comprising the compressed air system according to claim 9 or 10.

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