Tire inflation system and commercial vehicle with a tire inflation system and method for operating a tire inflation system

Description

[0001] The invention relates to a tire inflation system, a commercial vehicle with a tire inflation system, and a method for operating a tire inflation system.

[0002] Tire inflation systems are already known from the prior art. These systems serve to pump air into a vehicle's tire while driving or without an external compressed air source, in order to achieve the required air pressure. The known systems use the vehicle's existing compressed air supply to inflate the tire, with the tire pressure level exceeding the system pressure being reached by a pump within the tire inflation system. To prevent over-inflation, a pressure regulating valve is used, which automatically stops inflation of the tire(s) once the set pressure is reached. However, a problem with the systems known from the prior art is that the pressure regulating valve makes it difficult or even impossible to precisely set the desired tire pressure.

[0003] US patent 2007 / 0144171 A1 discloses a compressed air regulation system for the pressure of tires mounted on a vehicle. The described tire pressure regulation system includes a compressed air source and an internal combustion engine unit equipped with a turbocharger, which in turn acts as the compressed air source.

[0004] DE 10 2008 062 048 A1 relates to a tire pressure control system for vehicles with pneumatic tires and a method for regulating tire pressure. The tire pressure control system includes a tire pressure sensor and a tire valve. A pressure distributor interacts with switching valves and a control unit. The tire pressure control system is connected to a pressure supply line via a pressure coupling.

[0005] It is therefore the object of the present invention to provide a system which enables simple, easy-to-adjust and safe inflation of the tires of a vehicle, in particular a commercial vehicle.

[0006] This problem is solved with a commercial vehicle according to claim 1 and with a method for operating a tire inflation system according to claim 11. Further features, advantages and embodiments will become apparent from the dependent claims, the description and the figures.

[0007] According to the invention, a tire inflation system is provided, in particular for use in a commercial vehicle.Advantageously, the tire inflation system comprises a control unit, a flow inlet, a pressure sensor, a switchable valve (in particular an electrically or magnetically switchable valve), and a flow outlet, wherein the flow inlet is connected or connectable to a compressed air system (in particular an air spring system), wherein the flow outlet is connected or connectable to a pressure chamber of a tire, wherein the control unit is connected to the pressure sensor and the switchable valve, wherein the pressure sensor is capable of detecting pressure at the flow outlet or at the flow inlet, and wherein the control unit is configured to open and / or switch the switchable valve depending on the detected pressure, in particular when the detected pressure at the flow outlet falls below or exceeds a threshold value.The tire inflation system serves to fill a tire with compressed air in order to achieve the required pressure. The tire inflation system is attached, in particular, to a commercial vehicle, especially a commercial vehicle trailer. A commercial vehicle within the meaning of the invention is, in particular, a vehicle with a permissible total weight of more than 3.5 t, preferably more than 7.5 t, particularly preferably more than 15 t, and most preferably more than 18 t. The commercial vehicle can be a trailer, in particular a semi-trailer, and / or a towed vehicle. The commercial vehicle is, in particular, a roadworthy and / or road-bound vehicle. The tire inflation system according to the invention has a flow inlet through which air can flow into the tire inflation system. Advantageously, the flow inlet is connected to a compressed air system, in particular that of the commercial vehicle.The tire inflation system can be operated or inflated using the vehicle's compressed air system. Advantageously, this air inlet can also serve as the power supply for the tire inflation system's pressure booster unit. The compressed air system of the vehicle connected to the air inlet can, in particular, be the system used to operate the vehicle's air springs. Alternatively, or preferably, the vehicle can also have mechanical suspension. For safety reasons, the air inlet can be equipped with an inlet shut-off valve to isolate the tire inflation system from the compressed air system. Furthermore, the tire inflation system also has an outlet, which is connected or connectable to the air chamber of one or more tires.The pressure chamber of a tire, as defined in the invention, is the volume enclosed by the tire, which must maintain a certain air pressure during operation to ensure proper rolling and / or operation of the tire on the road. Advantageously, the tire inflation system, which can also be referred to simply as an inflation system, is not load-dependent. In other words, the tire inflation system can operate independently of the tire load or is itself load-independent. Therefore, the tire inflation system can operate independently of the load on the tires. This is particularly advantageous for operational reliability. The inlet of the inflation system can be used to introduce compressed air into the tire inflation system, and the outlet can be used to convey air from the tire inflation system into the tire(s) to be inflated.In addition to the flow inlet and outlet, the tire inflation system also includes a control unit, at least one pressure sensor, and a switchable valve. The control unit is connected to the pressure sensor (electronically) so that the measured value from the pressure sensor can be transmitted to the control unit. Furthermore, the switchable valve is also connected to the control unit, allowing the control unit to influence, switch, or control the switching state of the valve. Preferably, the switchable valve(s) is a solenoid valve to achieve a particularly simple and reliable valve switching mechanism. Advantageously, the control unit is connected to a bus system, in particular a CAN bus system of the vehicle to which the tire inflation system is connected.This allows the control unit to transmit and / or receive information from other control units of the vehicle, particularly in commercial vehicles. The pressure sensor of the tire inflation system is specifically arranged and / or designed to detect pressure at the flow outlet and / or the flow inlet. Advantageously, this pressure detection can be limited to static pressure and / or the pressure sensor can also be capable of detecting dynamic pressure. Advantageously, the system has at least two pressure sensors, one of which determines or measures the pressure at the flow inlet and / or the other measuring the pressure at the flow outlet. These two sensors can therefore be referred to as the flow inlet sensor and the flow outlet sensor, respectively, or as the flow inlet pressure sensor and the flow outlet pressure sensor.Advantageously, these two sensors, or all sensors, especially pressure sensors, of the tire inflation system are connected to the control unit. The control unit is designed and / or configured to open, switch, and / or close the valve(s) or the switchable valve(s) depending on the detected pressure. The valve, which can also be referred to as a switchable valve, is expediently arranged in the tire inflation system such that, when the valve is open, an airflow can flow directly or indirectly from the flow inlet to the flow outlet through the valve (open position), and / or, in another switching position, the valve does not allow any airflow from the flow inlet to the flow outlet (closed position).The switchable valve can be arranged and / or designed within the tire inflation system such that its switching position determines whether a direct and / or indirect airflow can flow from the flow inlet to the flow outlet and / or from the flow outlet to the tire(s) being inflated. By using a pressure sensor in a control unit and a switchable valve, it is possible to variably adjust the target pressure in the tire, as the control unit can easily set the threshold value that triggers the valve to open or close. Advantageously, the valve or switchable valve of the tire inflation system is designed to have an electrical connection and / or to be switched by magnetic forces.This allows for a particularly compact and simple control or switching option for the switchable valve.

[0008] Advantageously, all pressure sensors connected to the control unit are located between the flow inlet and the flow outlet. In other words, all pressure sensors capable of transmitting information to the control unit can be designed to determine pressures only between the flow inlet and the flow outlet. Therefore, the control unit is specifically not connected to any pressure sensor(s) that could measure or detect the pressure in a tire, air spring, or the vehicle's suspension system.

[0009] Advantageously, the control unit has an information output, and the control unit is designed to output a signal, in particular a warning signal, at the information output when the value detected by the pressure sensor of the tire inflation system, or its time derivative, exceeds and / or falls below a threshold. The warning signal can also be referred to as a warning signal. The information output of the control unit can be connected, or be connectable, to a bus system and / or another information system of the vehicle. The output warning signal can therefore be used, in particular, to activate a warning light and / or an acoustic or haptic signal for an operator of the commercial vehicle and / or the vehicle in which the tire inflation system is installed.By designing the tire inflation system to output a warning signal when the pressure measured at the flow inlet or outlet and / or its time derivative exceeds or falls below a threshold, the vehicle user can be easily informed that the tire is experiencing overpressure, underpressure, a leak, or is not functioning correctly. Leakage can be detected, in particular, by measuring the pressure over time. Overpressure and underpressure in the system and / or the tire, on the other hand, can be easily identified by an absolute pressure measurement.Furthermore, by analyzing the measured pressure value over time, particularly at the flow inlet and / or outlet, it can be determined whether, for example, a pressure booster unit is operating correctly. In other words, the pressure sensor can detect pressure fluctuations, which provide a clear indication of, for example, a pump cycle and / or the opening time of a switchable valve in relation to a pressure change. This can also be used if no pump is present or if a pump or pressure booster unit is bypassed. Additionally, or alternatively, a long-term pressure value is recorded, along with its time derivative, allowing for the determination of whether the long-term increase in atmospheric pressure, particularly the moving average over 2-40 seconds, corresponds to the counted pump cycles.However, if the pressure increase does not correspond to the number of pump cycles, the control unit can easily detect a malfunction in the tire inflation system and / or the tire and / or the pressure supply system or at the flow inlet. This allows the tire inflation system and its control unit to be used in various ways to detect a malfunction in the tire inflation system and / or its surrounding components (tire and compressed air system) and / or to inform the driver of such a malfunction, particularly via the information output. The information output can be connected to a telematics system. The telematics system can be used to inform a person at a distance. A person at a distance is defined as someone who is more than 100 meters, preferably more than 1000 meters, and most preferably more than 10 kilometers away from the telematics system.In particular, the remote person could be a fleet manager or a (fleet manager) server.

[0010] According to the invention, the control unit is an electronic control and / or monitoring unit. Such an electronic control and / or monitoring unit can also be referred to as an ECU and / or be designed as such. By designing the control unit to be an electronic control and / or monitoring unit, an interface for a vehicle's bus system can be implemented in a particularly simple manner. Furthermore, such control units are also particularly cost-effective.

[0011] The valve, which is preferably a switchable valve or can be described as such, is advantageously a solenoid valve. This allows for particularly simple and quick switching of the valve or switchable valve.

[0012] Advantageously, the tire inflation system is designed in such a way that the pressure at the flow outlet is greater when the valve is open than at the flow inlet. In In other words, the tire inflation system can create a pressure increase between the flow inlet and the flow outlet. This pressure increase can occur not only when the valve is open but also when it is closed. Advantageously, however, at least when the valve is open and functioning correctly, the pressure at the flow outlet is higher than at the flow inlet. This pressure increase between the flow inlet and the flow outlet can be achieved, in particular, by a pressure booster unit.

[0013] Advantageously, the tire inflation system includes a pressure booster unit, which is preferably a pressure increaser. Alternatively, and preferably, the pressure booster unit can also be a pump, a pressure compensator, a pressure rocker, a peristaltic pump, a turbocharger, and / or a turbine. By providing a pressure booster unit, a higher pressure can be achieved at the flow outlet than at the flow inlet in a simple and effective manner. InIn other words, a pressure booster unit can be used to increase the pressure within the tire inflation system, allowing a low-pressure (air) system, particularly an air suspension system, of the vehicle to be used as the inflation system, while still ensuring a sufficiently high pressure at the outlet. The pressure booster unit can be connected to the control unit, enabling the control unit to manage and / or regulate the pressure booster unit. InIn other words, the control unit can selectively intervene in the (operating) state of the pressure boosting unit. If the pressure boosting unit is a pressure increaser, this allows for a particularly compact system that requires no external connections, thus enabling a highly autonomous system. If, on the other hand, the pressure boosting unit is a pump, this allows for a particularly cost-effective and simple design. A peristaltic pump is particularly preferred as the pressure boosting unit, since this prevents contamination of the air with lubricants, thus preventing the tire valves of the tires being inflated from becoming clogged with lubricants. Advantageously, the pressure boosting unit can also be a turbocharger and / or a turbine.A turbocharger and / or turbine enables a continuous, open-loop delivery process, allowing for virtually uninterrupted inflation of the tire(s). Advantageously, the turbocharger is powered by the same compressed air system that supplies the air inlet. If the pressure booster unit is a rocker arm, this offers a further cost-effective alternative design.

[0014] Preferably, the pressure boosting unit has a power connection, through which the energy required for pressure increase enters or can enter the pressure boosting unit. Advantageously, the power connection of the pressure boosting unit is connected to the flow inlet. In other words, the pressure boosting unit is supplied with energy via the flow inlet.

[0015] According to the invention, the pressure increase capacity or pressure increase ratio of the pressure increase unit lies in the range of 1.2 to 1.8. The pressure increase capacity or pressure increase ratio denotes the ratio between the inlet and outlet pressure of the pressure increase unit, or between the pressure at the flow inlet and the flow outlet. Alternatively, or preferably, the ratio can also denote the ratio between the pressure at the outlet of the pressure increase unit and the pressure at the inlet of the pressure increase unit. A ratio of 1.05 to 2.6 allows for a particularly wide operating range while simultaneously preventing overloading of the system. If the ratio lies in the range of 1.1 to 2.0, particularly good energy utilization or a particularly high efficiency can be achieved.

[0016] According to the invention, the pressure boosting unit, which can in particular be a pressure increaser, comprises one or two double pistons or double-acting cylinders or pistons. This allows for a particularly compact design. Advantageously, the two double-acting pistons or cylinders are mechanically connected to each other, in particular by a piston rod. This results in a particularly compact force transmission between the pistons. Mechanical connection means, in particular, that the two elements cannot be separated from each other or displaced relative to each other.

[0017] Advantageously, the pressure boosting unit has an outlet and / or a vent, the outlet or vent connecting the pressure boosting unit to the environment, particularly directly. This allows for simple venting of the pressure boosting unit. Advantageously, a silencer is arranged in or on the outlet or vent to reduce noise pollution in the surrounding area. In addition to a direct connection, one or more of the switchable valves can also be arranged in the vent.

[0018] Preferably, the pressure booster unit, which can in particular be a pressure increaser, has a housing, wherein the housing is made, or at least partially made, of an aluminum alloy and / or a fiber-reinforced plastic. The housing serves to protect the pressure booster unit against external influences. The use of aluminum and / or fiber-reinforced plastic results in a particularly lightweight unit, which leads to an increase in payload, especially in commercial vehicles.

[0019] In an advantageous embodiment, the flow inlet is directly or indirectly connected to an inlet of the pressure boosting unit, and / or an outlet of the pressure boosting unit is directly or indirectly connected to the flow outlet. Direct connection means, in particular, that lines run directly from one element to the other, especially without a valve and / or a pump or other elements being arranged between them. However, with direct connection, flow path bifurcations or even valves, especially only the switchable valve, can be provided without disrupting the "direct" connection. Indirect connection means, in particular, that between the two relevant points to be connected, not only flow bifurcations but also other elements, such as...A pressure booster unit and / or valves or other fluid mechanics elements. By connecting the flow inlet to the inlet of the pressure booster unit, the existing pressure at the flow inlet can be easily utilized, thus reducing the workload on the pressure booster unit. By connecting an outlet of the pressure booster unit to the flow outlet, the fluid pumped by the pressure booster unit, especially compressed air, can be used for tire inflation in a particularly simple way.

[0020] In an additionally or alternatively preferred embodiment, the pressure boosting unit comprises at least one, preferably two or a plurality of displacement elements, in particular pistons in a cylinder head, advantageously in a double-acting cylinder. Displacement elements within the scope of the invention are, in particular, those elements which are displaced and / or rotated within the pressure boosting unit in order to achieve a volume displacement and / or change in the conveying chamber of the pressure boosting unit and / or to achieve the conveying of the conveying fluid, in particular compressed air. For example, pistons, turbine blades, and / or variable hose volumes can therefore be designated as displacement elements within the meaning of the invention. By providing displacement elements, a pressure increase by the pressure boosting unit can be achieved in a particularly simple manner.A hydrostatic pressure boosting unit is particularly preferred. In other words, the pressure boosting unit can be designed such that it achieves the pressure increase through a closed thermodynamic process. Advantageously, the pressure boosting unit comprises one or more displacement elements in the form of one or more double-acting cylinders. Pleasingly, two of these double-acting cylinders are mounted and / or arranged on the same piston rod and / or connected to each other by a mechanical linkage, so that the movement of one double-acting cylinder automatically causes or results in the movement of the other double-acting cylinder. This allows for a particularly space-saving pressure boosting unit, especially in the form of a pressure increaser.

[0021] In an advantageous embodiment, the pressure boosting unit incorporates or is connected to a linear motor. The use of a linear motor allows for a particularly efficient and compact drive for the displacement element(s) and / or piston of the pressure boosting unit. Furthermore, a linear motor can also be used to precisely adjust and / or determine the stroke or displacement volume of the pressure boosting unit.

[0022] In an advantageous embodiment, the pressure boosting unit comprises a magnetic force source, in particular an electromagnet, wherein the magnetic forces induced by the magnetic force source act directly or indirectly on a displacement element of the pressure boosting unit and are advantageously able to change its spatial position. In other words, the pressure boosting unit can have an element that imitates or can induce magnetic forces, wherein the counterpart to this magnetic force source is directly or indirectly connected to a displacement element of the pressure boosting unit, such that the forces initiated by the magnetic force source can effect a change in the spatial position of the displacement element of the pressure boosting unit. For example, the magnetic force source can be designed "similarly" to a stator of an electric motor, and the displacement element similarly to a rotor of an electric motor.Therefore, to achieve a small size for the pressure boosting unit, it is particularly advantageous if the magnetic forces induced by the magnetic force source act directly on the displacement element of the pressure boosting unit, especially a piston or piston rod. By designing the actuation or drive of the displacement elements in this way, an operating principle similar to a "railgun" can be achieved, where the "projectile" can be the displacement element or its equivalent.

[0023] Advantageously, the tire inflation system has a pressure input sensor capable of detecting pressure at the flow inlet. For example, the tire inflation system can have an additional pressure sensor capable of detecting the pressure at the inlet of the tire inflation system. With such a pressure input sensor, the tire inflation system can detect its pneumatic operational readiness. InIn other words, the pressure input sensor can easily detect when there is insufficient air pressure at the flow inlet to operate the tire inflation system. The pressure input sensor is advantageously connected to the tire inflation system's control unit, allowing the control unit to be fed with the value detected by the pressure input sensor. Advantageously, the switchable valve is a 2 / 2-way valve. Alternatively, or preferably, one or more of the switchable valves is a 3 / 2-way or a 4 / 2-way valve. By providing only two switching positions for the switchable valve, the valve can be switched relatively quickly and reliably, thus increasing the reliability of the tire inflation system.

[0024] If the switchable valve is a 2 / 2 way valve, this allows for a particularly compact valve, thus saving valuable installation space.

[0025] If the switching valve is a 3 / 2-way valve, a targeted airflow from the flow inlet to the flow outlet can be achieved in a particularly simple design via different paths. For example, the tire inflation system can be designed such that one of the ports of the 3 / 2-way valve is connected to the flow inlet, and other ports are optionally or switchably connected to a connecting line and / or to the pressure booster unit. This allows the type of tire inflation to be quickly and selectively adapted to the existing pressure at the flow inlet.In particular, such a design allows the tire inflation system to selectively decide whether to establish a direct airflow between the inlet and outlet – for example, via a connecting line – or whether the (compressed) air flowing from the inlet to the outlet should pass through the pressure booster unit. Bypassing the pressure booster unit allows for particularly fast and easy inflation, which should be used especially when the pressure at the outlet is lower than the pressure at the inlet and / or when the required pressure is low, as can be the case with dual tires.

[0026] If a 4 / 2-way valve is used, it is possible, in particular, to connect the pressure sensor, especially the pressure inlet sensor, either to the environment or the flow inlet, and simultaneously to connect the pressure booster unit to either the flow inlet or the environment. By selectively connecting the pressure sensor to either the flow inlet or the environment, the pressure sensor, especially the flow inlet sensor, can be used to detect if the switchable valve is stuck. In other words, the pressure sensor can be used to monitor the correct operation of the switchable valve. This selective distinguishability allows for...Connecting the pressure boosting unit to the flow inlet or the environment ensures that even if the pressure supply system malfunctions, especially the air spring system, or the flow inlet becomes blocked, the tire inflation system continues to function, because ambient air is used to inflate the tire instead of the flow inlet.

[0027] Advantageously, the pressure sensor(s), in particular the pressure input sensor and / or the pressure output sensor, is / are arranged on a circuit board of the control unit. This allows for a particularly compact control-sensor unit, which, due to its compactness, is easy to install, incurs low storage costs during the manufacturing process, and also saves valuable installation space.

[0028] Advantageously, the tire inflation system includes a connecting line, which directly connects the flow inlet, particularly exclusively via the valve, to the flow outlet. In other words, the tire inflation system can be designed such that an airflow from the flow inlet, via the connecting line and through the valve, or via the switchable valve and the connecting line, directly connects the flow inlet to the flow outlet. This allows for a direct supply of air from the flow inlet to the tire, particularly without routing the airflow through the pressure booster unit of the tire inflation system. This is especially advantageous when low tire pressure needs to be quickly remedied by the tire inflation system and / or when the tire inflation system or the flow outlet is fluidly connected to a dual tire.Furthermore, such a design can reduce the filling time and / or the energy consumption of the tire filling system, especially at low tire pressures.

[0029] Advantageously, the tire inflation system includes a vent valve, which, in one of its switching positions, connects the flow outlet directly to the environment. Therefore, the vent valve can serve to directly connect the flow outlet to the environment, thereby reducing the pressure within the tire inflation system, particularly at the flow outlet. The vent valve can be connected to the control unit and / or be a self-acting valve. The advantage of a self-acting valve is that it provides an additional safety feature. The advantage of a vent valve that can be switched by the control unit is that the tire pressure can be selectively reduced by the control unit.Such a measure may be necessary and / or preferred, for example, in the event of a significant increase in tire temperature, a change in the road surface and / or an unintentional over-inflation of the tire with compressed air.

[0030] In an advantageous embodiment, the drain valve can be switched by the control unit. Such a design provides a particularly simple way to selectively reduce the pressure in the tires, especially to a freely selectable value.

[0031] Advantageously, a check valve and / or a non-return valve are arranged between the flow inlet and the switchable valve. The term "between" here refers to the fact that a check valve and / or a non-return valve may be provided "in" a flow path between the flow inlet and the switchable valve. Therefore, the term "between" should be understood in a flow direction. The check valve advantageously prevents air or compressed air from flowing from the tire inflation system into the supply system, particularly the compressed air system of the supplying vehicle or commercial vehicle. This prevents pressure loss. The non-return valve serves to ensure that a certain minimum inflation pressure is present at the flow inlet.It is advantageous to provide both a check valve and a non-return valve, as this dual arrangement of both valve types allows for a particularly safe and efficient tire inflation system.

[0032] Advantageously, the tire inflation system includes a temperature sensor that can determine the ambient temperature or the compressed air temperature within the system, particularly at the air inlet. Advantageously, the tire inflation system can also include multiple temperature sensors.

[0033] Preferably, only one switchable valve is located between the flow inlet and the pressure boosting unit, particularly at the inlet of the pressure boosting unit. This allows the pressure loss to be kept low, resulting in a particularly energy-efficient system.

[0034] Preferably, only a switchable valve is located between the pressure boosting unit, in particular the output of the pressure boosting unit, and the flow outlet. This allows the pressure loss to be kept low, resulting in a particularly energy-efficient system.

[0035] Advantageously, the switchable valve fluidically connects or disconnects the inlet of the pressure boosting unit from the flow inlet. In other words, the switchable valve, or one of the valves, can fluidically connect the flow inlet to the pressure boosting unit, in particular the inlet of the pressure boosting unit, in one switching position and disconnect it in the other. This allows for a particularly compact system.

[0036] Advantageously, the switchable valve fluidically connects or disconnects the output of the pressure booster unit from the flow output. In other words, the switchable valve, or one of the valves, can fluidically connect the flow output to the output of the pressure booster unit—or, more generally, the pressure booster unit—in one switching position and disconnect it in the other. This allows for a particularly compact system.

[0037] Another aspect of the invention may relate to a commercial vehicle comprising a tire inflation system as described above and below. Advantageously, the flow inlet of the tire inflation system is connected or connectable to a compressed air system of the commercial vehicle, in particular to a compressed air system of an air spring of the commercial vehicle, and / or the flow outlet of the tire inflation system is advantageously connected or connectable to a pressure chamber of a tire of the commercial vehicle. In other words, the tire inflation system may be arranged in the commercial vehicle such that compressed air from a compressed air system of the commercial vehicle can flow via the flow inlet of the tire inflation system into the fluid interior or the flow lines and the compressed air-receiving structures of the tire inflation system, and / or from these volumes or...The compressed air volume of the tire inflation system can flow or be conveyed via the system's flow outlet into the pressure chamber of a tire on the commercial vehicle. Advantageously, all tires, especially load-bearing tires, of the commercial vehicle are fluidically connected to the flow outlet. Therefore, for example, all tires of the commercial vehicle can be inflated using the tire inflation system. Load-bearing tires of the commercial vehicle are specifically those tires that support the vehicle's axles. The axles are those axles that support and / or bear the load of the commercial vehicle relative to the road when the vehicle is in motion. These tires can be dual tires and / or single tires.

[0038] Another aspect of the invention may relate to a method for operating a tire inflation system, in particular as described above and below. Advantageously, this method comprises the following steps: Determining the pressure at a flow outlet of the tire inflation system; advantageously transmitting the determined pressure value to a control unit; comparing the determined pressure with a target pressure by the control unit; in particular, actuating a pressure boosting unit of the tire inflation system, especially by the control unit, when the pressure is below the target pressure or a threshold value.

[0039] The method according to the invention ensures in a particularly simple way that if the pressure in the tire drops, it can be refilled or the pressure increased again. Advantageously, the target pressure is a fixed value. In other words, this value is not variable. Therefore, the method does not measure the tire pressure, but only the pressure at the flow outlet. Alternatively or additionally, the pressure at the flow inlet can also be measured.

[0040] In an advantageous embodiment of the method, this comprises the following steps: Determining the delivered volume flow rate of a pressure boosting unit, in particular the tire inflation system; determining the increase in pressure at the flow outlet of the tire inflation system; determining whether the pressure increase is less than the expected pressure increase, in particular due to the volume and / or the volume of the tires to be inflated and / or the volume of the tire inflation system.

[0041] By determining the delivered volume flow rate, in particular by counting pump cycles, pump strokes and / or revolutions and / or cylinder strokes of, for example, the displacement elements of the pressure boosting unit, and by determining the pressure increase at the flow outlet of the tire inflation system and comparing it with an expected pressure, it can be determined, in particular, whether a leak and / or the replacement of a tire and / or the tire valve is necessary. The expected pressure increase can be easily determined by knowing the volume supplied by the tire inflation system and / or the tire and by applying basic thermodynamic principles. Advantageously, this expected pressure increase or the delivered volume flow rate can be determined by the control unit of the tire inflation system.

[0042] In a further alternative or additionally preferred embodiment of the method for operating a tire inflation system, in particular as described above and below, this comprises the following steps: Determining the time between two successive pumping cycles of the pressure booster unit; comparing the time and / or the change in time between two pumping cycles, whereby a warning is issued by the control unit if a threshold is exceeded. By determining the times between two successive pumping cycles of the pressure booster unit and comparing the change in time with a target pressure, it can be easily determined whether the pressure booster unit is functioning correctly. In particular, it can be determined that if the time interval between two successive pumping cycles or pumping strokes is too short, the desired target pressure differential cannot be achieved by the pressure booster unit. A pumping cycle is defined specifically as a displacement element of the pressure booster unit completing exactly one operating period or one revolution.A running period means, in particular, that the displacement element of the pressure boosting unit has left a position and, after one cycle, has returned to exactly the same position.

[0043] The method according to the invention may in particular have features that have already been described in the context of the tire inflation system and / or the commercial vehicle and / or will be described below. InIn other words, the method for operating the tire inflation system can also have the features described above with regard to the device(s), and conversely, the device can have features described in connection with the method for operating a tire inflation system. In particular, the control unit of the tire inflation system can be designed and / or configured to implement the features described above, especially in the tire inflation system described above and below.

[0044] Further advantages and features of the present invention will become apparent from the following description with reference to the figures. Individual features disclosed in the illustrated embodiments may also be used in other embodiments, unless this has been expressly excluded. The figures show: Figure 1 shows a first embodiment of a tire inflation system; Figure 2 shows a second embodiment of a tire inflation system; Figure 3 shows a third embodiment of a tire inflation system; Figure 4 shows a fourth embodiment of a tire inflation system; Figure 5 shows a fifth embodiment of a tire inflation system; Figure 6 shows a sixth embodiment of a tire inflation system; Figure 7 shows a seventh embodiment of a tire inflation system; Figure 8 shows an eighth embodiment of a tire inflation system; Figure 9 shows a ninth embodiment of a tire inflation system; and Figure 10 shows a tenth embodiment of a tire inflation system.

[0045] In Figure 1A tire inflation system is shown. The tire inflation system is connected via the flow inlet 1 to a compressed air system of a commercial vehicle, which is an air suspension compressed air system, also known as the compressed air system of an air spring, of the commercial vehicle. This system can also be referred to as the inflation or supply system. Downstream of the flow inlet 1, a bypass valve 2 is arranged. Downstream of the bypass valve 2, a flow-related branch is provided through which the pressure sensor 11, which is a flow inlet sensor 11 (in particular an indirect one), is able to determine the pressure at the flow inlet 1. Further downstream is the switchable valve 13, which can be switched by an electric current and by an electromagnet.The switchable valve 13 is connected to the control unit 12, enabling the control unit 12 to switch the valve 13 into various positions. The control unit 12 has an information output 14. Through this output 14, the control unit 12, which is an ECU in the figure, can transmit information to a vehicle system, in particular via a bus system, to other control units of a vehicle, and / or be connected to a display to show error messages and / or other information, especially pressure values ​​from the pressure sensors 10, 11, to a user. In addition to or as an alternative to the output 14, the control unit 12 can also have an input through which information can be transmitted to the control unit 12.To increase the pressure above the pressure present at the flow inlet 1, which can be determined by the flow inlet sensor 10, the tire inflation system has a pressure booster unit 3. In this case, the pressure booster unit 3 has two double-acting cylinders coupled to each other via a piston rod. The pressure booster unit 3 has an ambient outlet on which a silencer 9 is arranged. Fluid can be discharged directly from the pressure booster unit 3 into the environment via this ambient outlet. The outlet of the pressure booster unit 3 is directly connected to the flow outlet 6, which is connected to several tires, as shown in the diagram. Figure 1As indicated. To determine the pressure present at the flow outlet 6, the tire inflation system has a pressure sensor 11, which is designed as a flow outlet sensor 11, because this determines how the Figure 1 The pressure at flow outlet 6 can be seen from the diagram. To prevent overloading of the system due to excessive pressure in the lines of the tire inflation system, a safety valve 5 is installed or arranged near and / or directly connected to flow outlet 6, which prevents overpressure in the system. Alternatively or additionally, preferably, the safety valve 5 can also be integrated into the pressure boosting unit 3, in particular such that it is directly connected to outlet 3.2.

[0046] In Figure 2 is a similar system to the one in the Figure 1 shown, whereby in the Figure 2The inlet of pressure boosting unit 3.1 and the outlet of pressure boosting unit 3.2 are marked. As the Figure 2 As can be seen, both the flow input sensor 10 and the flow output sensor 11 are part of the control unit 12. This control unit 12 can also be referred to as a control device. The one in the Figure 2 The switchable valve 13 used is a 4 / 2-way valve. In the Figure 2 In the situation shown, the pressure input sensor 10 is connected to the environment via the switchable valve 13, so that a "sticking" of the switchable valve 13 can be detected via the pressure sensor 10 or the flow input sensor 10.

[0047] In Figure 3 A tire inflation system is shown which differs fundamentally from those in the Figures 1 and 2 The variants shown differ. In the Figure 3In the depicted variant, the flow inlet 1 is directly connected to the flow outlet 6 via the connecting line 22. Therefore, the tire inflation system according to the Figure 3 via no pressure boosting unit.

[0048] In Figure 4 is a tire inflation system similar to the one in the Figure 2 The tire inflation system shown is described, with the system operating according to the Figure 4 The device has a drain valve 24 which can be switched by the control unit 12. In other words, the control unit 12 can therefore move the drain valve 24 into its two different switching positions. The drain valve 24 is located in the Figure 4 designed as a solenoid valve. The drain valve 24 allows for easy pressure reduction at the flow outlet 6, thus preventing over-inflation of the tire or tires to be inflated, or reducing the pressure in the tire.

[0049] In Figure 5A tire inflation system is shown which, via the switchable valve 13, is able to connect the flow inlet 1 to the flow outlet 6 either via the pressure booster unit 13 or via the connecting line 22. In other words, the switchable valve 13, controlled by the control unit 12, can ensure that an airflow flows from the flow inlet 1 through the pressure booster unit 3 to the flow outlet 6, or directly from the flow inlet 1 or the switchable valve 13 via the connecting line 22 to the flow outlet 6. Furthermore, a bypass valve 2 and a check valve 34 are located between the switchable valve 13 and the flow inlet 1. The check valve 34 prevents fluid from flowing back from inside the tire inflation system to the flow inlet 1.The overflow valve 2, on the other hand, serves to ensure that the compressed air at the flow inlet 1 has a certain minimum pressure.

[0050] In Figure 6A tire inflation system is shown. The tire inflation system has a pressure booster unit 3 with an input 3.1 and an output 3.2. The information output 14 of the control unit 12 is connected to a 24V CAN bus or forms one—at least partially. However, the CAN bus can also have a lower voltage, e.g., 12 volts or 5 volts. This CAN bus can be provided in any embodiment of the invention. The pressure booster unit 3 is connected to the environment via a vent, the vent having a silencer 9, which can also be referred to as a muffler. The switchable valve 13 is connected to the control unit 12, the switchable valve 13 being a 2 / 2-way valve. The 2 / 2-way valve, or the switchable valve 13, is located in a supply line of the pressure booster unit 3 or connects or disconnects the input 3 in terms of flow.1 of the pressure boosting unit 3 from the flow inlet 1. Both the flow inlet 1 and the flow outlet 6 are each connected to a pressure sensor so that the pressure can be measured or recorded there.

[0051] In Figure 7 is one of the Figure 6 A similar configuration is shown. The switchable valve 13 is also connected to the control unit 12, and the switchable valve 13 is a 2 / 2-way valve. The 2 / 2-way valve, or the switchable valve 13, is located in a branch of the pressure boosting unit 3 and / or connects or disconnects the output 3.2 of the pressure boosting unit 3 from the flow output 6. Both the flow inlet 1 and the flow output 6 are each connected to a pressure sensor 10, 11, so that the pressure can be measured or recorded there.

[0052] In Figure 8 is one of the Figure 6 or 7A similar design is shown. However, the switchable valve 13 is located in the vent of the pressure boosting unit 3.

[0053] In Figure 9 Another embodiment of a tire inflation system is shown. This tire inflation system, similar to the embodiment in the Figure 5A connecting line 22 is provided, which connects the flow inlet 1 directly to the flow outlet 6, thus bypassing the pressure boosting unit 3. To prevent backflow through the connecting line 22, a check valve 34 is arranged within the connecting line 22. The switchable valve 13 can connect the connecting line 22 as well as the pressure boosting unit 3 to the flow inlet 1 or disconnect both simultaneously. Advantageously, in the illustrated embodiment, the desired pressure at the flow outlet 1 is no more than 15% lower than the desired tire pressure or the pressure at the flow outlet 6.

[0054] In Figure 10Another embodiment of a tire inflation system is shown. This embodiment is characterized in particular by the fact that a switchable valve 13 is arranged in both the connecting line 22 and the supply line to the pressure boosting unit 3. This makes it possible to counteract even large leaks in a tire, especially through the connecting line 22. The connecting line 22, which can also be referred to as a bypass, can also be equipped with a switchable valve and / or a check valve 34 in other embodiments. Reference symbol list:

[0055] 1- Flow inlet 2- Overflow valve 3- Pressure booster unit 3.1- Inlet of pressure booster unit (3) 3.2- Outlet of pressure booster unit (3) 5- Safety valve 6- Flow outlet 9- Silencer 10- Pressure sensor / Flow inlet sensor 11- Pressure sensor / Flow outlet sensor 12- Control unit 13- Switchable valve 14- Information output 22- Connecting line 24- Drain valve 34- Check valve

Claims

1. Commercial vehicle comprising a tire inflation system, where the commercial vehicle is a commercial vehicle trailer, wherein the tire inflation system comprises a control unit (12), a flow inlet (1), a pressure sensor (10, 11), a switchable, in particular an electrically and / or magnetically switchable, valve (13) and a flow outlet (6), wherein the flow inlet (1) is or can be connected to a compressed air system, in particular to a compressed air system of an air spring, wherein the flow outlet (6) is or can be connected to a pressure chamber of a tire, wherein the control unit (12) is connected to the pressure sensor (10, 11) and the switchable valve (13), wherein the pressure sensor (10, 11) is able to detect a pressure at the flow outlet (6) or at the flow inlet (1), wherein the control unit (12) is designed such that it opens and / or switches the switchable valve (13) as a function of the detected pressure, in particular when the detected pressure at the flow outlet (6) falls below a threshold value, wherein the tire inflation system has a pressure increasing unit (3), wherein the pressure increasing unit (3), which may in particular be a pressure booster, has one or two double pistons or double-acting cylinders or double-acting pistons, and wherein the control unit (12) is an electronic control and / or monitoring unit (ECU), characterized in that the pressure increasing capability and / or the pressure increasing ratio of the pressure increasing unit (3) is in a range from 1.2 to 1.8.

2. Commercial vehicle according to claim 1, wherein the pressure increasing unit (3) has an energy connection, wherein the energy required to increase the pressure reaches or is able to reach the pressure increasing unit (3) through the energy connection, wherein, in particular, the energy connection of the pressure increasing unit (3) is connected to the flow inlet (1).

3. Commercial vehicle according to any of the preceding claims, wherein the tire inflation system has a pressure inlet sensor (10), wherein the pressure inlet sensor (10) is able to detect a pressure at the flow inlet (1).

4. Commercial vehicle according to any of the preceding claims, wherein the switchable valve (13) is a 2 / 2-way valve.

5. Commercial vehicle according to any of the preceding claims, wherein the switchable valve (13) is a 3 / 2-way valve or a 4 / 2-way valve.

6. Commercial vehicle according to any of the preceding claims, wherein the pressure sensor and / or the pressure sensors (10, 11), in particular the pressure inlet sensor (10), is / are arranged on a circuit board of the control unit (12).

7. Commercial vehicle according to any of the preceding claims, wherein the tire inflation system has a connecting line (22), wherein the connecting line (22) connects, in particular directly, the flow inlet (1) to the flow outlet (6) via the switchable valve (13).

8. Commercial vehicle according to any of the preceding claims, wherein a back pressure valve (34) and / or an overflow valve (2) without backflow is / are arranged between the flow inlet (1) and the switchable valve (13).

9. Commercial vehicle according to any of the preceding claims, wherein the flow inlet (1) is or can be connected to a compressed air system of the commercial vehicle, in particular to a compressed air system of an air spring of the commercial vehicle, and / or wherein the flow outlet (6) is or can be connected to a pressure chamber of a tire of the commercial vehicle.

10. Commercial vehicle according to any of the preceding claims, where the commercial vehicle trailer is a semitrailer.

11. Method of operating a tire inflation system of a commercial vehicle trailer according to any one of the preceding claims, comprising the steps: - Determining the pressure at a flow outlet (6) of the tire inflation system; - Comparing of the determined pressure with a target pressure by a control unit (12); - In particular, actuating a pressure increasing unit (3) of the tire inflation system when the pressure is below the target pressure.