Method for detecting air spring leaks

Abstract

Method for detecting a leak of at least one air spring (100) of a vehicle (200), the vehicle (200) comprising: - at least one air spring (100) comprising a height sensor (10) and a pressure sensor (20), - a temperature sensor (30) for measuring a temperature, in particular an ambient temperature, - a control unit (ECU), the method comprising - measuring (110) a first height (h1) by the height sensor (10), a first pressure (p1) by the pressure sensor (20), and a first temperature (T1) by the temperature sensor (30), - measuring (130) a second height (h2) by the height sensor (10), and a second pressure (p2) by the pressure sensor (20), - Determining (150) a leakage of the at least one air spring (100) by the control unit (ECU) as a function of the first height (h1), the second height (h2), the first pressure (p1), the second pressure (p2) and the first temperature (T1).

Description

[0001] The invention relates to a method for detecting a leakage of at least one air spring according to the independent method claim, a corresponding air spring, a corresponding computer program product, a computer-readable data carrier, a control unit for carrying out the method and a corresponding vehicle with a corresponding control unit.

[0002] Vehicles with air springs are known, whereby the height of an air spring, in particular “how low” the vehicle or the air spring is, can be adjustable. A vehicle can, for example, have at least one air spring, for example one air spring per wheel. The height (in particular length) of an air spring can be adjusted using compressed air. For example, the air spring can be pressurized with compressed air to increase the height. Alternatively, compressed air can be released from the air spring to reduce the height. It can also be provided that the air spring, a pressure accumulator (e.g. for compressed air) and / or a connecting line (in between) has a leak. This can cause air or pressure to (unintentionally) escape and / or be reduced.

[0003] The state of the art has disadvantages. For example, the detection of a leak is not possible or only inadequate. For example, the accuracy and / or reliability of leak detection may be insufficient. Furthermore, it may be that an (unnecessary) amount of information, in particular sensors and / or sensor data, is required. Furthermore, it may be that the detection of a leak and / or the compensation of pressure losses is (only) possible by using several / all control units and / or when starting the engine. Furthermore, changes in temperature are not taken into account in known methods and / or systems. This can lead to an incorrect assessment of the pressure and / or volume. This can reduce accuracy. A "tilted position" of the vehicle, in particular due to different heights (e.g.Differences in air spring performance (e.g. due to leakage) between different air springs cannot therefore be compensated for, or can only be compensated for inadequately, in state-of-the-art vehicles, systems and / or processes.

[0004] It is therefore an object of the present invention to at least partially overcome at least one of the disadvantages described above. In particular, the object of the invention is to provide an improved method for detecting a leak in at least one air spring. Furthermore, it may be an object to detect a leak taking into account a temperature, in particular a temperature change between a first and a second point in time. Furthermore, it may be an object to improve safety, appearance, and / or confidence in the vehicle.

[0005] The above object is achieved by a method for detecting a leak in at least one air spring according to the independent method claim, an air spring according to the independent device claim, a computer program product having the features of the independent computer program product claim, a computer-readable data carrier having the features of the independent patent claim relating to a computer-readable data carrier, a control unit having the features of the independent patent claim relating to a control unit, and a vehicle having the features of the independent vehicle claim. Further features and details of the invention emerge from the subclaims, the description, and the drawings.Features and details described in connection with the method according to the invention naturally also apply in connection with the computer program product according to the invention and / or in connection with the computer-readable data carrier according to the invention and / or in connection with the control unit according to the invention and / or in connection with the vehicle according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is or can always be made to each other. In particular, advantages that are described in the context of the first, second, third, fourth, and / or fifth aspect also apply to the first, second, third, fourth, and / or fifth aspect.

[0006] The above object is achieved according to a first aspect by a method for detecting a leakage of at least one air spring (in particular according to the second aspect) of a vehicle, the vehicle comprising: - at least one air spring comprising a height sensor - a pressure sensor, - a temperature sensor for measuring a temperature, in particular an ambient temperature, - a control unit, the method comprising - measuring a first altitude by the altitude sensor, a first pressure by the pressure sensor, and a first temperature by the temperature sensor, - Measuring a second height by the height sensor, and a second pressure by the pressure sensor, - Determining a leakage of the at least one air spring by the control unit as a function of the first height, the second height, the first pressure, the second pressure and the first temperature.

[0007] The method according to the first aspect can be computer-implemented and / or performed repeatedly. Preferably, the method can be performed during or before each use of the vehicle, for example, when the vehicle is unlocked. Alternatively or additionally, the method can be performed at (regular) intervals, for example, every three hours (see below). The control unit can implement the method, particularly where appropriate, for example by controlling the sensors, the air spring, a pressure accumulator, and / or a compressor.

[0008] Preferably, the method is designed to detect a leakage of the at least one air spring, a pressure accumulator and / or at least one connecting line (between).

[0009] The vehicle can have at least one air spring, in particular four air springs (e.g. for each wheel or in each "corner" of the vehicle). It can be provided that the at least one or each air spring can be or is connected (reversibly) to a pressure accumulator and / or a compressor for pressurizing or releasing compressed air. Accordingly, the pressure in the at least one air spring can be adjusted via the pressure accumulator and / or compressor. The pressure accumulator preferably has a (constant) volume. For example, it can be rigidly constructed, e.g. from steel.

[0010] The at least one air spring can have a height sensor and / or a pressure sensor. Alternatively or additionally, the pressure sensor can be connected to the pressure accumulator. The height sensor can be configured to measure the height (or length) of the air spring. It can be provided that the height is lower at lower pressure. It can be provided that the height is greater at higher pressure. The pressure sensor can be configured to measure a (first and / or second) pressure (in particular air pressure) in the at least one air spring and / or the pressure accumulator. It can be provided that the height sensor and / or pressure sensor are connected to a control unit, for example via a data connection, whereby in particular data can be transmitted from the sensor to the control unit and / or the control unit can control the sensor, for example to carry out a measurement.

[0011] The vehicle may also have a temperature sensor. This may, for example, be controllable via a second or separate control unit. The temperature sensor may be configured to measure a temperature, in particular an ambient temperature (outside temperature). Provision may be made for the temperature sensor and / or the second control unit to be connected to the control unit, for example via a data connection, whereby data may, in particular, be transmitted from the sensor to the control unit. Accordingly, the control unit may be configured to receive the (measured) temperature. Provision may be made for the control unit (itself) not to be able to initiate a temperature measurement. Provision may be made for the temperature to influence the altitude and / or the pressure.In particular, temperature changes, for example between a first and a second point in time, can influence the (first and / or second) height and / or the (first and / or second) pressure.

[0012] The (first) measurement of a first altitude by the altitude sensor, a first pressure by the pressure sensor, and a first temperature by the temperature sensor can preferably be carried out at a first point in time, for example when parking, switching off, and / or locking the vehicle. Provision can be made for the (first) temperature to be measured, and in particular for it to be comparatively high (e.g., due to engine heat and / or the time of day). The first altitude, the first pressure, and / or the first temperature can preferably be specific to the first point in time. Preferably, the first altitude, the first pressure, the first temperature, and / or the first point in time can be stored by the control unit, for example, in a memory unit of the control unit. Provision can be made for these to be loaded at a later (in particular, a second) point in time.

[0013] The (second) measurement of a second altitude by the altitude sensor and of a second pressure by the pressure sensor can preferably be carried out at a second point in time, for example during a wake-up, when (re)starting, switching on and / or unlocking the vehicle. Alternatively or additionally, it can be provided that the second point in time has a time interval from the first point in time, in particular stored by and / or predetermined by the control unit. For example, the time interval can be between one second and 10 days, in particular between 10 seconds and 3 days, for example between 60 seconds and 1 day, preferably between 30 minutes and 12 hours, particularly preferably between 1 hour and 6 hours, ideally between 2 and 4 hours. Accordingly, the time interval between the first point in time and the second point in time can be, for example, 3 hours.It may be particularly preferred that no (second) temperature is measured or measurable at the second point in time. It may be provided that the second temperature differs from the first temperature, for example due to changes in the ambient temperature, time of day, and / or cooling of the engine and the like. The second altitude, the second pressure and / or the second temperature can preferably be specific to the second point in time. Preferably, the second altitude, the second pressure, the second temperature and / or the second point in time can be stored by the control unit, for example in a memory unit of the control unit. It may be provided to load these at a later (in particular a second or further) point in time.The second height may be lower than the first, particularly since a drop in pressure may be more likely and / or a (potentially existing) leak may lead to a pressure loss. However, the opposite may also be the case under certain circumstances.

[0014] The determination of a leak in the at least one air spring by the control unit, as a function of the first height, the second height, the first pressure, the second pressure and the first temperature, can be based at least on these (aforementioned) variables. Preferably, precisely these variables can be measured and / or no further variables are known or measured. Particularly preferably, the determination can be carried out without measuring a second temperature. Preferably, the determination of a leak can be carried out by comparison, in particular as a function of the first and second points in time, for example by comparing the first height with the second height, the first pressure with the second pressure, the first temperature with a second temperature and / or variables derived from these variables.

[0015] It can be provided that the detection of a leak is carried out depending on repeated execution of the method. For example, the method can be carried out repeatedly over an observation period. For example, the observation period can be between 60 seconds and 10,000 days, in particular between 30 minutes and 1,000 days, for example between 1 hour and 365 days, preferably between 6 hours and 100 days, particularly preferably between 1 day and 50 days, ideally between 3 to 30 days. Alternatively or additionally, the observation period can be dependent on the mileage of the vehicle. For example, a mileage can be between 1 km and 1,000,000 km, in particular between 10 km and 10,000 km, for example between 50 km and 5,000 km, preferably between 100 km and 1,000 km, particularly preferably between 300 km and 800 km.It may be particularly preferred to determine a leak as a function of a (repeatedly) determined leak rate, wherein the leak rate can be observed, for example, as a function of the observation period and / or the mileage. In the event of a (larger or increasing) leak, the leak rate of the at least one air spring can, for example, (substantially) increase, in particular over an observation period and / or a mileage. It can be provided that the determination of a leak by the control unit includes detecting an exceedance of a leak rate limit.For example, a leakage velocity limit value can be between 0.01 mm / h and 1000 mm / h, in particular between 0.1 mm / h and 100 mm / h, for example between 1 mm / h and 50 mm / h, preferably between 2 mm / h and 20 mm / h, particularly preferably between 3 mm / h and 10 mm / h, ideally between 5 mm / h and 7 mm / h. If, for example, a leakage velocity limit value of 5 mm / h is exceeded, in particular repeatedly, the control unit can detect a leak in the at least one air spring.

[0016] Within the scope of the invention, it may be advantageous that after the (first) measurement, the control unit carries out: - Controlling by the control unit, the altitude sensor for transmitting the first altitude, the pressure sensor for transmitting the first pressure and the temperature sensor for transmitting the first temperature to the control unit, in particular in order to store these in a memory unit of the control unit, in particular comprising a first time at which the measurement is carried out.

[0017] Within the scope of the invention, it is conceivable that after the (second) measurement, the control unit carries out: - Controlling by the control unit, the height sensor for transmitting the second height, and the pressure sensor for transmitting the second pressure, to the control unit, in particular in order to store them in a memory unit of the control unit, in particular comprising a second time, in particular comprising a second time at which the measurement is carried out.

[0018] Within the scope of the invention, it can be provided that the determination comprises loading, by the control unit, the first altitude, the second altitude, the first pressure, the second pressure, and the first temperature, in particular from a memory unit of the control unit, preferably into a computing unit of the control unit. It can also be provided to load further (comparison) data. For example, (stored or historical) expected altitude changes, actual altitude changes, and / or leakage rates can be loaded.

[0019] It is further conceivable that the determination comprises calculating a second temperature as a function of the first pressure, the second pressure and the first temperature.

[0020] Preferably, a second temperature may not be available and / or measurable. Accordingly, the method can preferably be carried out without (re-)measuring a (second) temperature. For example, this can be the case if communication with the temperature sensor and / or a second control unit connected thereto is inactive. In this case, it can be provided that the control unit carries out the method, in particular at a second point in time (e.g., wake-up or readjustment), in order to preferably provide readjustment, e.g., by supplying additional air from a compressor (e.g., to the pressure accumulator and / or the at least one air spring), for example, before a user of the vehicle has approached the vehicle (e.g., is within sight). Advantageously, the vehicle can thus always be adjusted so that it is (visibly) upright. In other words, different heights of different air springs can be compensated for.This can improve the appearance and / or the driver's confidence in the vehicle. Alternatively, it can be provided that the second temperature is measured, for example analogously to the first temperature. It can be provided that a temperature change is determined (in particular estimated) without determining a second temperature. Preferably, a temperature change can be determined as a function of a (measured) pressure change. It can be particularly preferred if the pressure in the pressure accumulator is measured by the pressure sensor. Preferably, the volume of the pressure accumulator can be constant and / or assumed to be constant. Accordingly, it can be provided to determine, calculate and / or estimate the second temperature. Preferably, the pressure accumulator can have the same temperature as the ambient temperature and / or outside temperature. In particular, it can be provided that the pressure accumulator is not filled immediately after the measurement.This can lead to a temperature increase, especially independent of the ambient temperature. It can therefore be calculated and / or applied, especially by the control unit (Equation 1): T1p1=T2p2

[0021] The volume, in particular a first volume V1 and a second volume V2, can be constant or assumed to be constant. T1 can be the first temperature. T2 can be the second temperature. p1 can be the first pressure. p2 can be the second pressure. By rearranging Equation 1, the following can be calculated and / or applied (Equation 2): T2=T1*p2p1 Accordingly, the second temperature can be calculated by the control unit depending on the first pressure, the second pressure and the first temperature.

[0022] It is also conceivable that the determination comprises calculating an expected altitude change as a function of the first altitude, the second altitude, the first pressure, the second pressure, the first temperature, and in particular a second temperature, and / or a reduction factor, wherein, in particular, the reduction factor is stored in the memory unit of the control unit and was preferably determined via calibration and / or simulation. In this case, it can be provided that the expected altitude change is (re)calculated, in particular at a second point in time.

[0023] A lowering factor can be specific to an air spring. For example, a first, second, third, and / or fourth air spring can have a first, second, third, and / or fourth lowering factor. This can be design-related. It can be determined through simulation, climate chamber tests, and / or calibration. The lowering factor can (in principle) exhibit a change in height depending on a temperature (change), for example, 3 mm / K. It can be provided that this is identical for all air springs. It can preferably be provided that the lowering factor is different for (the air springs of the) rear axle (e.g., 1 mm / K) and / or (the air springs of the) front axle (e.g., 0.8 mm / K). Alternatively, it can be provided that the lowering factors of the front axle and the rear axle are identical. The lowering factor can depend (significantly) on the design of the axle (e.g., air volume and / or axle load, etc.).

[0024] Particularly preferably, the expected height change can be determined as a function of a lowering factor A of the air spring, the first temperature T1, and / or the second temperature T2. In particular, the following can be calculated (by the control unit) and / or apply: Δherw=(T2−T1)*A

[0025] Accordingly, the (determined, and preferably not measured) second temperature can be used to calculate a (realistically) expected elevation change. Particularly preferably, the expected elevation change can depend (exclusively) on the temperature (change), and preferably not on a (possible) leak. For example, a temperature change of 10°C can cause the vehicle to descend by 8 mm at the front axle. The descent factor can be 0.8 mm / °C.

[0026] The second temperature can be calculated (as above, e.g. equation 2). In other words, an expected height change can comprise a height change expected under realistic conditions and / or in the absence of (undesired) leaks. It can be provided that an expected height change, in particular the lowering factor, is design-related, in particular for the at least one air spring, an axle (e.g. front axle or rear axle) of the air spring and / or the medium (in particular the air) with which the air spring can be filled. Alternatively or additionally, the expected height change, in particular the lowering factor, can be determined by calibration under predefined conditions, for example during commissioning, or by simulation (during development).Alternatively or additionally, an expected height change and / or a lowering factor can be determined from comparison data, for example, from identical vehicles and / or a vehicle fleet. Comparison data can be stored in the control unit and / or retrieved (and / or stored) by the control unit, in particular via a data connection, for example, to the Internet and / or a backend (e.g., the manufacturer's).

[0027] Within the scope of the invention, it is optionally possible for the determination to comprise calculating an actual change in altitude as a function of the first altitude and the second altitude.

[0028] The actual change in altitude can be determined by calculating the difference between the first altitude and the second altitude (or vice versa). It can therefore be calculated, particularly by the control unit, and / or the following applies (Equation 3): Δhist=h2−h1

[0029] Furthermore, it can be provided within the scope of the invention that the determination comprises a comparison, in particular a difference formation, of the expected height change and the actual height change, wherein in particular - a determination that there is no leakage occurs if the comparison shows no deviation or a deviation (equal to or) below a height limit value between the actual height change Δh_ist and the expected height change Δh_erw, in particular Δh_ist - Δh_erw ≤ height limit value, whereby in this case in particular a leakage speed (see below) of v = 0 mm / h is assumed and / or can be expected (e.g. when smoothing), - a leak is detected if the comparison shows a deviation above (or equal to) a height limit between the actual height change and the expected height change, in particular Δh_actual - Δh_expected ≥ height limit.

[0030] The height limit can be 0 mm, for example. It can be provided that a determination of whether a leak is present (or not) is carried out individually for each air spring. For example, for a vehicle, this can preferably be done for each of at least one, at least two, preferably four, air springs, in particular for "every corner" of the vehicle.

[0031] With regard to the present invention, it is conceivable that the determination comprises calculating a leakage rate as a function of the first height, the second height, in particular an actual change in height and / or an expected change in height, and a time interval between the measurement of the first height and the measurement of the second height, in particular a difference between the second time and the first time.

[0032] A leakage velocity v can be calculated, in particular by the control unit, and / or the following can apply (equation 4): v=ΔhLeakaget2−t1=Δhist−ΔherwΔt

[0033] It can be provided that the leakage velocity can only be calculated using equation 4 if the actual height change is greater than (or equal to) an expected height change, in particular Δh ist > Δh erw Preferably, the leakage rate can be determined independently of the temperature change, the first temperature, and / or the second temperature. In other words, the influence of temperature can be eliminated. Preferably, the leakage rate is (only) dependent on a leakage-related drop and / or the time interval.

[0034] This makes it possible to determine whether there is a (relatively) rapid drop or a (large) loss of air from at least one air spring. A loss of air or pressure can be (limitedly) compensated by a compressor (e.g., by further supplying compressed air). Advantageously, it can be detected whether a drop or leak has already progressed so far that it can no longer be compensated or will soon no longer be compensated. In this case, a warning message can be issued, for example, to prompt the driver to visit a workshop. A warning message can be issued to a driver via the vehicle, in particular a display device, and / or a mobile device of the driver, for example, a smartphone, a smartwatch, a computer and / or a vehicle key. A leakage speed limit value (in particular, an upper limit for the leakage speed) can be set, for example, in the control unit (e.g.,the storage unit). If this leakage rate limit is detected, particularly by the control unit, this may trigger the output of a warning message (by the control unit).

[0035] It can be provided that, in particular when the method is carried out repeatedly, different values ​​for the leakage rate and / or for the actual change in height are smoothed, in particular by the control unit. The smoothing can comprise (temporal) averaging, in particular to compensate for outliers and / or incorrect measurements. In this case, an average value for a number of measurements (e.g. simply repeating the method) can have between 2 and 10,000, in particular between 3 and 1,000, for example between 5 and 100, preferably between 8 and 64, particularly preferably between 10 and 48, ideally between 12 and 32. This can enable more stable behavior, increased reliability and / or improved detection. In this case, smoothing can preferably be carried out by the control unit. The control unit can (comparatively) detect a leak more quickly and / or earlier.Alternatively or additionally, smoothing can take place in a backend connected to the control unit. It can be provided that smoothing is (only) carried out if at least one leak is detected, in particular for at least one air spring. If, for example, no leak was detected in at least one or all other air springs, the leakage velocity can preferably be assumed to be v = 0 mm, which can be used in particular for smoothing. This can preferably achieve a more stable result. In particular, it can be determined more reliably (in particular over an observation period) whether a leak (actually) exists. This allows outliers to be compensated for.

[0036] It can be provided that the detection of a leak (or the above-mentioned steps), in particular the comparison of the actual and expected altitude change and / or the verification of the altitude limit and / or the leak speed limit, is performed in the control unit. Alternatively or additionally, it can be provided that this occurs in the backend. This allows for an improved comparison with identical vehicles and / or an entire vehicle fleet. Thus, a more robust and / or reliable detection of a leak can be achieved.

[0037] The above object is achieved according to a second aspect by an air spring according to the invention for a vehicle, wherein the air spring is designed to implement the method according to the first aspect, in particular in cooperation with a vehicle.

[0038] The at least one air spring can be connected to a pressure accumulator and / or a compressor. It can (also) be provided that the compressor is connected to the pressure accumulator. The compressor can increase and / or decrease the pressure in the pressure accumulator and / or the at least one air spring. It can be provided that the at least one air spring is connected to the pressure accumulator via a line and / or a valve. Accordingly, the pressure accumulator can be (reversibly) decoupled from the at least one air spring. The volume of the pressure accumulator can be constant or kept constant, in particular between a first and a second point in time.

[0039] This results in the same advantages with regard to an air spring according to the invention according to the second aspect as have already been described with regard to a method according to the invention according to the first aspect.

[0040] The above object is achieved according to a third aspect by a computer program product according to the invention, comprising instructions which, when the computer program product is executed by a computer, cause the computer to implement the method according to the first aspect.

[0041] This results in the same advantages with regard to a computer program product according to the invention according to the third aspect as have already been described with regard to a method according to the invention according to the first aspect and / or an air spring according to the invention according to the second aspect.

[0042] The above object is achieved according to a fourth aspect by a computer-readable data carrier according to the invention in which instructions are stored which, when executed by a computer, cause the computer to carry out the method according to the first aspect.

[0043] Thus, with regard to a computer-readable data carrier according to the invention according to the fourth aspect, the same advantages arise as have already been described with regard to a method according to the invention according to the first aspect and / or an air spring according to the invention according to the second aspect and / or a computer program product according to the invention according to the third aspect.

[0044] The above object is achieved according to a fifth aspect by a control unit according to the invention, comprising a computing unit and a memory unit in which instructions are stored which, when at least partially executed by the computing unit, carry out a method according to the first aspect.

[0045] It can be provided that the control unit is designed as a main control device, which is in particular connected to further, second and / or other control units. In this case, the control unit can be activated first ("wake up"), in particular upon start-up, wake-up, unlocking and / or a (second) time, while further control units are preferably inactive, in particular until the control unit has performed a height adjustment of the at least one air spring. Accordingly, the control unit can (quickly) compensate for different heights of different air springs. In this case, it can be provided (as described above) that a (second) temperature is not (measurably) available, but is preferably calculated (as above).

[0046] This results in the same advantages with regard to a control unit according to the invention according to the fifth aspect as have already been described with regard to a method according to the invention according to the first aspect and / or an air spring according to the invention according to the second aspect and / or a computer program product according to the invention according to the third aspect and / or a computer-readable data carrier according to the invention according to the fourth aspect.

[0047] The above object is achieved according to a sixth aspect by a vehicle according to the invention comprising a control unit according to the fifth aspect and / or at least one air spring according to the second aspect.

[0048] The vehicle preferably comprises at least one air spring, preferably four air springs, in particular for each wheel. The vehicle preferably comprises four wheels. The vehicle can therefore stand upright, in particular with respect to a longitudinal axis and / or transverse axis, by having different air springs of (as much as possible) the same height. The control unit can be configured to perform or achieve level control or "uprightness" of the vehicle, in particular by the method according to the first aspect.

[0049] This results in the same advantages with regard to a vehicle according to the invention according to the sixth aspect as have already been described with regard to a method according to the invention according to the first aspect and / or an air spring according to the invention according to the second aspect and / or a computer program product according to the invention according to the third aspect and / or a computer-readable data carrier according to the invention according to the fourth aspect and / or a control unit according to the invention according to the fifth aspect.

[0050] Further advantages, features, and details of the invention will become apparent from the following description, in which several embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description may be essential to the invention individually or in any combination. In the drawings: Fig. 1 a procedure Fig. 2 a vehicle Fig. 3 a leakage rate.

[0051] In the following figures, identical reference numerals are used for the same technical features, even for different embodiments.

[0052] Fig. 1 shows a method for detecting a leakage of at least one air spring 100 of a vehicle 200, the vehicle 200 comprising - at least one air spring 100 comprising a height sensor 10 - a pressure sensor 20, - a temperature sensor 30 for measuring a temperature, in particular an ambient temperature, - a control unit ECU, the method comprising - measuring 110 a first height h1 by the height sensor 10, a first pressure p1 by the pressure sensor 20, and a first temperature T1 by the temperature sensor 30, - Measuring 130 a second height h2 by the height sensor 10, and a second pressure p2 by the pressure sensor 20, - Determining 150 a leakage of the at least one air spring 100 by the control unit ECU as a function of the first height h1, the second height h2, the first pressure p1, the second pressure p2 and the first temperature T1.

[0053] It can be provided that after the measurement 110 the control unit ECU carries out: - Controlling 120, by the control unit ECU, the height sensor 10 for transmitting the first height h1, the pressure sensor 20 for transmitting the first pressure p1 and the temperature sensor 30 for transmitting the first temperature T1 to the control unit ECU, in particular to store them in a memory unit MU of the control unit ECU, in particular comprising a first time t1 at which the measurement 110 is carried out.

[0054] It can be provided that after the measurement 130 the control unit ECU carries out: - Controlling 140, by the control unit ECU, the height sensor 10 for transmitting the second height h2, and the pressure sensor 20 for transmitting the second pressure p2, to the control unit ECU, in particular in order to store them in a memory unit MU of the control unit ECU, in particular comprising a second time t2, in particular comprising a second time t2 at which the measurement 130 is carried out.

[0055] The determining 150 may include calculating 151 a second temperature T2 as a function of the first pressure p1, the second pressure p2 and the first temperature T1.

[0056] Furthermore, it can be provided that the determination 150 comprises a calculation 152 of an expected altitude change Δh_erw as a function of the first altitude h1, the second altitude h2, the first pressure p1, the second pressure p2, the first temperature T1, and in particular a second temperature T2, and / or a lowering factor A, wherein in particular the expected altitude change Δh_erw is stored in the memory unit MU of the control unit ECU, and was preferably determined via a calibration and / or a simulation.

[0057] It can also be provided that the determination 150 comprises a calculation 153 of an actual height change Δh_ist as a function of the first height h1 and the second height h2.

[0058] In addition, it is conceivable that the determination 150 comprises a comparison 154, in particular a difference formation 155, of the expected height change Δh_erw and the actual height change Δh_ist, wherein in particular: - a determination 156 that there is no leakage occurs if the comparison 154 shows no deviation or a deviation (equal to or) below a height limit value between the actual height change Δh_actual and the expected height change Δh_expected, - a leak is detected 157 if the comparison 154 shows a deviation above a height limit value between the actual height change Δh_actual and the expected height change Δh_expected.

[0059] Alternatively or additionally, it can be provided that the determining 150 comprises a calculation 158 of a leakage velocity v as a function of the first height h1, the second height h2, in particular an actual height change Δh_ist and / or an expected height change Δh_erw, and a time interval Δt between the measuring 110 of the first height h1 and the measuring 130 of the second height h2, in particular a difference between the second time t2 and the first time t1.

[0060] Fig. 2 shows a vehicle 200 with at least one air spring 100. This is arranged, for example, on the rear axle. By way of example, a further air spring 100 is arranged on the front axle. The at least one air spring 100 has a height sensor 10, which is configured to measure a (first and / or second) height h1, h2. The at least one air spring can be connected to a pressure accumulator 50, in particular via lines (such as pipes or hoses). By way of example, a pressure sensor 20 is arranged on the pressure accumulator 50. The pressure sensor 20 is configured to measure a first pressure p1 and / or a second pressure p2. The vehicle also comprises a temperature sensor 30, which is particularly preferably configured to measure (only) a first temperature T1. The temperature sensor 30 can measure a second temperature T2. The vehicle 200 also comprises a control unit ECU having a computing unit CU and a memory unit MU.The ECU control unit can be connected to the height sensor 10, the pressure sensor 20, the temperature sensor 30, and / or the pressure accumulator 50, for example, via a (respective) data connection. This allows (measurement) data to be exchanged and / or control to take place. The first height h1, in particular at a first time t1, can preferably differ from a second height h2, in particular at a second time t2. Preferably, the second height h2 can be lower than the first height h1 (lowering of the air spring).

[0061] Fig.3 shows a leakage rate v (y-axis), for example as a function of time t or an observation period and / or a mileage of the vehicle (x-axis). For example, a vehicle with four air springs can be assumed. The leakage rate for the air spring(s) 100 at the front right Fr_Re, front left Fr_Li, rear right Hi_Re, and rear left Hi_Li is shown. The (respective) leakage rate can vary and, in particular, can become larger or smaller. This can be reduced (at least partially) by smoothing. However, in particular, if an air spring 100 has a (larger) leak, this can be determined by exceeding a leakage rate limit value v_grenz, wherein, for example, an air spring 100 at the rear right of the vehicle Hi_Re (first) exceeds the leakage rate limit value.The course (of Hi_Re) can be increasing, but in particular it is not necessarily (strictly) monotonically increasing. List of reference symbols 10 Altitude sensor 20 pressure sensor 30 Temperature sensor 50 pressure accumulators 100 air spring 200 vehicles ECU control unit CU computing unit MU storage unit 110 Measuring first height h1, first pressure p1, and first temperature T1 120 Control to transmit h1, p1, T1 130 Measuring a second height h2, and a second pressure p2 140 Control to transmit h2, p2 150 Determining a leak in at least one air spring 151 Calculating a second temperature T2 depending on p1, p2 and T1 152 Calculating an expected height change Δh_erw 153 Calculating an actual height change Δh_ist 154 Comparing the actual and expected elevation change 155 Calculating the difference between the actual and expected height change 156 Determine that there is no leak 157 Detecting a leak 158 Calculating a leakage velocity t time t1 first time point h1 first height p1 first print T1 first temperature t2 second time point h2 second height p2 second print T2 second temperature A reduction factor Δh_erw expected altitude change Δh_ist actual height change v Leakage rate v_grenz leakage speed limit Fr_Li air spring front left Fr_Re air spring front right Hi_Li air spring rear left Hi_Re air spring rear right

Claims

[1] Method for detecting a leakage of at least one air spring (100) of a vehicle (200), the vehicle (200) comprising - at least one air spring (100) comprising a height sensor (10), - a pressure sensor (20), - a temperature sensor (30) for measuring a temperature, in particular an ambient temperature, - a control unit (ECU), the method comprising - measuring (110) a first height (h1) by the height sensor (10), a first pressure (p1) by the pressure sensor (20), and a first temperature (T1) by the temperature sensor (30), - measuring (130) a second height (h2) by the height sensor (10), and a second pressure (p2) by the pressure sensor (20), - Determining (150) a leakage of the at least one air spring (100) by the control unit (ECU) as a function of the first height (h1), the second height (h2), the first pressure (p1), the second pressure (p2) and the first temperature (T1). [2] Method according to claim 1, characterized by , that after measuring (110) the control unit (ECU) carries out - Controlling (120), by the control unit (ECU), the altitude sensor (10) for transmitting the first altitude (h1), the pressure sensor (20) for transmitting the first pressure (p1) and the temperature sensor (30) for transmitting the first temperature (T1) to the control unit (ECU), in particular in order to store them in a memory unit (MU) of the control unit (ECU), in particular comprising a first time (t1) at which the measurement (110) is carried out. [3] Method according to claim 1 or 2, characterized by that after measuring (130) the control unit (ECU) carries out - Controlling (140), by the control unit (ECU), the height sensor (10) for transmitting the second height (h2), and the pressure sensor (20) for transmitting the second pressure (p2), to the control unit (ECU), in particular in order to store them in a memory unit (MU) of the control unit (ECU), in particular comprising a second time (t2), in particular comprising a second time (t2) at which the measurement (130) is carried out. [4] Method according to one of the preceding claims, characterized by that the determining (150) comprises loading, by the control unit (ECU), the first height (h1), the second height (h2), the first pressure (p1), the second pressure (p2) and the first temperature (T1), in particular from a storage unit (MU) of the control unit (ECU), preferably into a computing unit (CU) of the control unit (ECU). [5] Method according to one of the preceding claims, characterized bythat the determining (150) comprises calculating (151) a second temperature (T2) as a function of the first pressure (p1), the second pressure (p2) and the first temperature (T1). [6] Method according to one of the preceding claims, characterized by that the determination (150) comprises calculating (152) an expected altitude change (Δh_erw) as a function of the first altitude (h1), the second altitude (h2), the first pressure (p1), the second pressure (p2), the first temperature (T1), and in particular a second temperature (T2), and / or a lowering factor (A), wherein in particular the expected altitude change (Δh_erw) is stored in the memory unit (MU) of the control unit (ECU) and was preferably determined via a calibration and / or a simulation. [7] Method according to one of the preceding claims, characterized bythat the determining (150) comprises calculating (153) an actual change in height (Δh_ist) as a function of the first height (h1) and the second height (h2). [8] Method according to one of the preceding claims, characterized by that the determination (150) comprises a comparison (154), in particular a difference formation (155), of the expected height change (Δh_erw) and the actual height change (Δh_ist), wherein in particular - a determination (156) that there is no leakage occurs if the comparison (154) shows no deviation or a deviation below a height limit value between the actual height change (Δh_ist) and the expected height change (Δh_erw), - a leak is detected (157) if the comparison (154) shows a deviation above a height limit value between the actual height change (Δh_ist) and the expected height change (Δh_erw). [9] Method according to one of the preceding claims, characterized by in that the determining (150) comprises calculating (158) a leakage velocity (v) as a function of the first height (h1), the second height (h2), in particular an actual height change (Δh_ist) and / or an expected height change, and a time interval (Δt) between the measuring (110) of the first height (h1) and the measuring (130) of the second height (h2), in particular a difference between the second time (t2) and the first time (t1). [10] Air spring (100) for a vehicle (200), wherein the air spring (100) is designed, in particular in cooperation with a vehicle (200), to implement the method according to one of the preceding claims. [11] A computer program product comprising instructions which, when the computer program product is executed by a computer, cause the computer to implement the method according to any one of the preceding claims. [12] Computer-readable data carrier in which instructions are stored which, when executed by a computer, cause the computer to carry out the method according to one of the preceding claims. [13] Control unit (ECU), comprising a computing unit (CU) and a memory unit (MU) in which instructions are stored which, when at least partially executed by the computing unit (CU), carry out a method according to one of the preceding claims. [14] Vehicle (200) comprising a control unit (ECU) according to the preceding claim and / or at least one air spring (100) according to one of the preceding claims

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