Method and device for monitoring the low-pressure sensor of the fuel system of an internal combustion engine

Abstract

A device for checking the low-pressure sensor of the low-pressure system of a fuel system for supplying fuel to an internal combustion engine is described. The device is configured to detect, based on a measurement signal from the low-pressure sensor, that a first criterion for the presence of a defect in the low-pressure sensor is met. The device is further configured, in response to detecting that the first criterion is met, to check, based on a change in the target fuel pressure in the low-pressure system, whether the low-pressure sensor is defective.

Description

The invention relates to a method and a corresponding device which are designed to monitor the low-pressure sensor of the low-pressure system of the fuel system for an internal combustion engine.An internal combustion engine driven (power) vehicle comprises a fuel system via which fuel is provided from a fuel tank to the internal combustion engine of the vehicle. The fuel system typically has a low-pressure system which is designed to provide fuel from the fuel tank in a defined manner, in particular at a defined setpoint pressure, to an injection pump in order to enable the injection pump to feed a defined amount of fuel to the internal combustion engine.The present document is concerned with the technical object of bringing about an efficient and reliable monitoring of the low-pressure system of a fuel system for an internal combustion engine, in particular in order to enable a precise setting of the fuel-air mixture for the operation of the internal combustion engine.The object is achieved by each of the independent claims. Advantageous embodiments are described inter alia in the dependent claims. It is pointed out that additional features of a claim dependent on an independent claim can form a separate invention which is independent of the combination of all features of the independent claim without the features of the independent claim or only in combination with a subset of the features of the independent claim and which can be made the subject matter of an independent claim, a divisional application or a subsequent application. This applies in the same way to technical teachings described in the description, which may form an invention independent of the features of the independent claims.According to one aspect, a device for checking the low-pressure sensor of the low-pressure system of a fuel system for supplying fuel to an internal combustion engine (in particular for a spark ignition engine or for a diesel engine) is described. The fuel system may include a fuel tank for receiving fuel. Fuel may be provided from the fuel tank via a low pressure pump in the low pressure system of the fuel system. The actual pressure of the fuel may be adjusted (by operation of the low pressure pump) to a certain desired pressure. Furthermore, measured values relating to the actual pressure of the fuel in the low-pressure system can be recorded on the basis of the low-pressure sensor.Fuel at a specific setpoint pressure can be provided at a high-pressure pump by the low-pressure system, it being possible for the high-pressure pump to be configured to provide fuel at an increased pressure in the internal combustion engine, in particular to inject it into the internal combustion engine.The device is configured to recognize, on the basis of a measurement signal of the low-pressure sensor, that a first criterion for the (possible) presence of an impairment of the low-pressure sensor is fulfilled. The measurement signal is preferably detected during normal operation of the fuel system. In this case, the setpoint pressure of fuel in the low-pressure system can be unchanged and / or constant during the detection period of the measurement signal. The measurement signal may comprise 50 or more, in particular 100 or more, measurement values for a corresponding sequence of successive points in time. The points in time can follow one another, for example, with a (constant) distance of 1 second or less, in particular of 1 / 10 second or less.The actual pressure of fuel in the low pressure system typically has a vibration around the desired pressure. The oscillation of the measurement signal can be effected by the high-pressure pump of the fuel system downstream of the low-pressure system. The high-pressure pump can be operated, for example, at a specific pump frequency, as a result of which recoils of fuel into the low-pressure system are effected at the pump frequency. As a result, oscillation of the actual pressure can be effected in the low-pressure system, the oscillation having a frequency corresponding to the pump frequency.The device can be configured to analyze a vibration of the measurement signal of the low-pressure sensor in order to check the first criterion for the presence of an impairment of the low-pressure sensor. In particular, it can be checked to check the first criterion whether the measurement signal has a vibration which corresponds to the vibration of the actual pressure in the low-pressure system expected (on account of the operation of the high-pressure pump).The device can be configured in particular to determine an indicator for the strength, in particular for the amplitude, of the oscillation of the measurement signal. This can be effected on the basis of a time-frequency transformation, in particular on the basis of a Fourier transformation. The indicator for the strength of the oscillation of the measurement signal can be, for example, the magnitude of at least one transformation coefficient, in particular a Fourier coefficient, at the frequency of the expected oscillation of the actual pressure in the low-pressure system corresponding to the pump frequency.The first criterion for the presence of an impairment of the low-pressure sensor can be checked in a precise manner on the basis of the indicator for the strength of the oscillation of the measurement signal, in particular in such a way that• the first criterion is detected as being fulfilled if the indicator for the strength of the oscillation of the measurement signal indicates a strength of the oscillation of the measurement signal which is less than a predefined threshold value; and / or• The first criterion is detected as not fulfilled if the indicator for the strength of the oscillation of the measurement signal indicates a strength of the oscillation of the measurement signal which is greater than the threshold value.It can thus be checked whether or not the measurement signal has a sufficiently strong oscillation in order to check the first criterion for the (possible) presence of an impairment of the low-pressure sensor.The first criterion for the (possible) presence of an impairment of the low-pressure sensor can be checked without causing a (dedicated) change in the setpoint pressure of fuel in the low-pressure system for this purpose and / or without intervening in the operation of the fuel system for this purpose. The first criterion can thus be checked in an efficient manner without having to change the normal operation of the fuel system in dedicated fashion for checking the low-pressure sensor.The device is further configured to check, in response to detecting that the first criterion is fulfilled, whether the low-pressure sensor (actually) has an impairment on the basis of a (dedicated) change in the setpoint pressure of fuel in the low-pressure system. For this purpose, the low-pressure pump of the fuel system may be caused to change the actual pressure of fuel in the low-pressure system according to the predetermined change of the desired pressure.The device is preferably configured to effect the change of the setpoint pressure of fuel in the low-pressure system for checking the low-pressure sensor only after it has been detected that the first criterion is fulfilled.Due to the dedicated change in the target pressure, deterioration of the low pressure sensor can be reliably detected. However, the change of the setpoint pressure is effected only when a suspected condition for the presence of an impairment (i.e. only when the satisfied first criterion is present). Thus, the low pressure sensor may be monitored reliably without substantially compromising fuel system operation.The device may be configured to ascertain a change in measured values of the low-pressure sensor that is brought about as a result of the change in the setpoint pressure of fuel in the low-pressure system. For example, at least one measured value before the change and at least one further measured value after the change of the setpoint pressure can be detected in order to determine a change (e.g. a difference) of measured values of the low-pressure sensor.It can then be checked in a reliable manner, based on the determined change of measurement values of the low-pressure sensor, in particular based on a comparison of the determined change of measurement values of the low-pressure sensor with the effected change of the setpoint pressure, whether the low-pressure sensor has an impairment. It can be determined, in particular, whether or not• the low-pressure sensor has as an impairment a sticking and / or a limitation of measured values; or• The low pressure sensor has no impairment and instead the fuel in the low pressure system has bubbles, in particular vapour bubbles.The device can be configured in particular to determine that the low-pressure sensor has an impairment (in particular a sticking and / or a limitation of measured values) if the ascertained change of measured values of the low-pressure sensor is smaller in absolute value than a change threshold value. The change threshold value typically depends on the effected change in the desired pressure.Furthermore, the device may be configured to determine that the low-pressure sensor does not have any impairment (and instead the fuel in the low-pressure system has bubbles, in particular vapor bubbles), if the ascertained change in measurement values of the low-pressure sensor is greater in absolute value than the change threshold value.The change in the setpoint pressure thus makes it possible to ascertain details with respect to the state of the low-pressure sensor and / or of the low-pressure system.The apparatus may be configured to cause at least one measure related to the internal combustion engine when it is determined that the low pressure sensor has a degradation. The measure can comprise, for example• outputting an indication to a user of the internal combustion engine; and / or• an adaptation, in particular a degradation, of the operation of the internal combustion engine.In this way, a particularly reliable operation of the fuel system and / or of the internal combustion engine can be effected.According to a further aspect, a fuel system for an internal combustion engine is described, which fuel system has the device described in this document.According to a further aspect, a (road) motor vehicle (in particular a passenger car or a truck or a bus or a motorcycle) is described, which comprises the device described in this document and / or the fuel system described in this document.According to one aspect, a method for checking the low-pressure sensor of the low-pressure system of a fuel system for supplying fuel to an internal combustion engine is described. The method comprises detecting, on the basis of a measurement signal of the low-pressure sensor (which was detected during normal operation of the fuel system), that a first criterion for the presence of an impairment of the low-pressure sensor is fulfilled. Further, in response to detecting that the first criterion is met, the method includes checking, based on a change in the desired pressure of fuel in the low pressure system, whether the low pressure sensor has degradation.It should be noted that the aspects described in connection with the device, in particular the claims described in connection with the device, are also to be applied to the method as corresponding method features.According to a further aspect, a software (SW) program is described. The SW program can be configured to be executed on a processor (e.g. on a control device of a vehicle) and thereby to execute the method described in this document.According to a further aspect, a storage medium is described. The storage medium may comprise a SW program which is configured to be executed on a processor and to thereby execute the method described in this document.It should be noted that the methods, devices, and systems described herein may be used both alone and in combination with other methods, devices, and systems described herein. Furthermore, various aspects of the methods, apparatus, and systems described herein may be combined with one another in a variety of ways. In particular, the features of the claims can be combined with one another in many ways. Furthermore, features listed in brackets are to be understood as optional features.The invention is described in more detail below with reference to exemplary embodiments. Figure shows FIG. 1 shows example components of a fuel system for providing fuel in an internal combustion engine; FIG. 2 ashows an exemplary time profile (i.e. a measurement signal) of the pressure measured by a low-pressure sensor in the low-pressure system of a fuel system; FIG. 2 b shows an exemplary frequency analysis of the pressure curve detected by the low-pressure sensor (i.e. of the measurement signal); FIG. 3 ashows an exemplary pressure curve measured by a non-impaired low-pressure sensor; FIG. 3 b shows an exemplary pressure curve measured by a low-pressure sensor that is adversely affected; and FIG. 4 is a flow chart of an example method for monitoring the low pressure sensor of a fuel system.As set forth at the outset, the present document is concerned with the efficient and reliable monitoring of the low-pressure system of a fuel system for providing fuel for the operation of an internal combustion engine, in particular an internal combustion engine of a motor vehicle. In this context, FIG. 1 shows an example fuel system 100 for an internal combustion engine 110 having a fuel tank 102 for receiving fuel 103. The fuel 103 may be directed via a fuel line 104 to a fuel delivery pump 105 (i.e., a low pressure pump) configured to adjust the actual pressure of the fuel 103 in the low pressure system of the fuel system 100. The low pressure system may include, for example, a fuel filter 106. Furthermore, the low-pressure system has a low-pressure sensor 107, which is configured to acquire sensor data relating to the actual pressure of the fuel 103 in the low-pressure system. The fuel delivery pump 105 may be operated (e.g., by a controller 101) in dependence on the sensor data of the low pressure sensor 107 to set the actual pressure of the fuel 103 in the low pressure system to a particular set point pressure.The low pressure system may cause fuel 103 to be provided to an injection pump 108 (i.e., a high pressure pump) of engine 110 at a certain desired pressure, such that precise adjustment of the fuel-air mixture for operation of engine 110 may be effected by injection pump 108.The low-pressure system of internal combustion engine 110 or of fuel system 100 is thus responsible for the fuel provision. The low-pressure system supplies the one or more downstream components of the injection system, e.g. a port injection or the high-pressure pump of a direct injection system, with fuel 103 having the desired pressure requested by these components. A low-pressure sensor 107 can be used to measure whether the set actual pressure of the fuel 103 corresponds to the setpoint pressure. The correctly adjusted actual pressure of the fuel 103 is typically decisive for the correct functioning of the components downstream of the low-pressure system and in particular for the correct adjustment of the fuel injection mass. For example, in the case of port injection, the injection time is typically determined as a function of the actual pressure of the fuel 103 in the low-pressure system. If the actual pressure measured by the low pressure sensor 107 is higher than the actual pressure actually present in the low pressure system, the injection time is too long and too much fuel 103 is injected, resulting in a rich fuel-air mixture for the operation of the internal combustion engine 110. If, on the other hand, the measured actual pressure is lower than the actual pressure actually present in the low-pressure system, the injection time is too short and too little fuel 103 is injected, which results in a lean fuel-air mixture for the operation of the internal combustion engine 110. Both a rich and a lean fuel-air mixture typically result in an impairment of the exhaust gas of the internal combustion engine 110.One possible error that may occur in the low-pressure sensor 107 is the "sticking" of the measurement signal of the low-pressure sensor 107 to a fixed value. As a result, there is no response of the low pressure sensor 107 to an actual pressure change in the low pressure system. In other words, the "sticking" of the measurement signal of the low-pressure sensor 107 typically leads to the low-pressure sensor 107 outputting a constant measurement signal even in the event of an actually present pressure change in the low-pressure system.The above-mentioned procedure is repeated. Fault pattern of the low-pressure sensor 107 can be detected on the basis of the fact that, due to the injection and / or high-pressure pump 108 of the fuel system 100, a oscillation of the actual actual pressure typically occurs in the low-pressure system. This vibration is generated by the repulsion of fuel 103 caused by the cams of the high pressure pump 108. The presence of the oscillation of the actual pressure in the low-pressure system can be used as an indicator for a fault-free and / or non-impaired low-pressure sensor 107. In the case of a "fixed", i.e. impaired, low-pressure sensor 107, there is typically no oscillation of the measurement signal of the low-pressure sensor 107.The (control and / or evaluation) device 101 can be configured to analyze the measurement signal of the low-pressure sensor 107 for the presence of a vibration in order to determine, on the basis of whether or not there is an impairment of the low-pressure sensor 107. In particular, the amplitude of the oscillation of the measurement signal of the low-pressure sensor 107 can be determined in order to determine, based on the amplitude, whether or not there is an impairment. For this purpose, the average amplitude of the oscillation of the measurement signal of the low-pressure sensor 107 can be determined with the aid of a Fourier transformation (in particular at a frequency which corresponds to the pumping frequency of the high-pressure pump 108). If the determined amplitude is less than a predefined amplitude threshold, it may be inferred that the low pressure sensor 107 has (possibly) an impairment.FIG. 2 ashows an exemplary measurement signal 202 of the low-pressure sensor 107, wherein the measurement signal 202 comprises a sequence of measurement values of the actual pressure 200 of the low-pressure system for a corresponding sequence of successive points in time. The measurement signal 202 can have measurement values with a specific sampling or measurement frequency. The sampling frequency may be 1 Hz or higher, or 10 Hz or higher. Furthermore, the measurement signal 202 may extend over a certain measurement and / or detection period, e.g. of 10 seconds or more, or of 30 seconds or more. As can be seen from FIG. 2 a, the measurement signal 202 of the actual pressure 200 has a vibration about the setpoint pressure 201.As already explained, the device 101 can be configured to operate the low-pressure pump 105 as a function of the measurement signal 202 in order to set (in particular to regulate) the actual pressure 200 to the predefined setpoint pressure 201.The measurement signal 202 can be transformed from the time domain into the frequency domain on the basis of a time-frequency transformation (e.g. on the basis of a Fourier transformation), as illustrated by way of example in FIG. 2 b. FIG. 2 b illustrates the magnitude 210 of a plurality of transformation coefficients 212, 213 (determined by the time-frequency transformation) for a corresponding plurality of different frequencies. The plurality of transform (in particular Fourier) coefficients 212, 213 typically has a transform coefficient 213 for the frequency zero. This transformation coefficient 213 represents the target pressure 201 about which the measurement signal 202 oscillates.Furthermore, the plurality of transformation coefficients 212, 213 comprises one or more transformation coefficients 212 at a frequency which corresponds to the (pumping) frequency of the oscillation of the measurement signal 202 caused by the high-pressure pump 108. The (pump) frequency of the operation of the high-pressure pump 108 is typically known, so that the expected frequency of the oscillation of the measurement signal 202 is also known. The magnitude 210 of the one or more transformation coefficients 212 for the one or more expected frequencies of the vibration of the measurement signal 202 may be considered an indicator of the magnitude of the vibration of the measurement signal 202, and may be compared to a predefined amplitude threshold 211 to detect degradation of the low pressure sensor 107. When the amount 210 is equal to or greater than the amplitude threshold 211, it may be inferred that there is no degradation of the low pressure sensor 107. If, on the other hand, the amount 210 is less than the amplitude threshold value 211, it can be concluded that (if appropriate) the low-pressure sensor 107 is impaired.On the basis of the analysis of the oscillation of the measurement signal 202 of the low-pressure sensor 107, it is thus possible to check whether or not a first (fault) criterion for the presence of an impairment of the low-pressure sensor 107 is fulfilled.The fuel 103 may have vapor bubbles in the low pressure system. Vapor bubbles in the fuel 103 may result in the oscillations of the fuel 103 being attenuated in the low pressure system and, as a result, the oscillation of the measurement signal 202 of the low pressure sensor 107 having a relatively low amplitude. This may result in the low-pressure sensor 107 being diagnosed as impaired on the basis of the above-mentioned (first) fault criterion, even though the low-pressure sensor 107 is not impaired.It can be checked by a second, downstream, error criterion whether the low-pressure sensor 107 detected as possibly impaired (on the basis of the first error criterion) is actually impaired (and in particular "stuck") or alternatively whether the low-pressure sensor 107 is not impaired (and in particular the fuel 103 has vapor bubbles).For the diagnosis of a "stuck" sensor 107, the oscillation of the measurement signal 202 can thus be analyzed in a first step in order to identify a first fault criterion. This first fault criterion can then be confirmed when the second fault criterion is present, so that the sensor 107 can be diagnosed as faulty in a reliable manner.As a second error criterion, it can be checked whether the measured value 200 of the low-pressure sensor 107 responds to a change in the setpoint pressure 201 in the low-pressure system. The checking of the second error criterion can be selectively triggered by the occurrence of the first error criterion. In particular, the check of the second error criterion can be effected selectively if the average amplitude 210 of the oscillation of the measurement signal 202 determined from the Fourier transformation is below the amplitude threshold value 211.For checking the second error criterion, the setpoint pressure 201 for the low-pressure system can be raised. The increased desired pressure 201 is typically effected by increasing the pumping capacity of the low-pressure pump 105. Due to the increase in the pressure in the low-pressure system, a corresponding change in the measured values 200 of the low-pressure sensor 107 is expected. The detected change of the measured values 200 of the low-pressure sensor 107 can be compared with the requested change of the setpoint pressure 201. If the detected change in the measurements 200 of the low pressure sensor 107 is too low (as compared to the requested change in the target pressure 201), it may be determined that the low pressure sensor 107 has degradation. On the other hand, if the detected change of the measured values 200 of the low-pressure sensor 107 matches the requested change of the target pressure 201, it can be determined that the low-pressure sensor 107 does not have any impairment, in particular it can be determined that the low-pressure sensor 107 does not "hang up".FIGS. 3 aand 3 b show exemplary measurement signals 321, 322 of the low-pressure sensor 107 in the case of no impairment (FIG. 3 a ) and in the case of an impairment (FIG. 3 b ). The desired pressure 201 for the low-pressure system is raised from a first value 301 to a second value 302 at a first point in time 311, and can be reduced again from the second value 302 to the first value 301 at a second point in time 312. In the example illustrated in FIG. 3 a, the measurement signal 321 follows the change in the value 301, 302 of the setpoint pressure 201, so that it can be determined that the low-pressure sensor 107 does not have any impairment. In the example illustrated in FIG. 3 b, the measurement signal 322 remains substantially unchanged even when the value 301, 302 of the setpoint pressure 201 changes, and therefore does not follow the change in the value 301, 302 of the setpoint pressure 201. In this case, it may be determined that the low pressure sensor 107 has degradation.FIG. 4 shows a flow diagram of a method 400 (optionally computer-implemented) for checking the low-pressure sensor 107 of the low-pressure system of the fuel system 100 for providing fuel 103 to an internal combustion engine 110. The fuel system 100 may include a low pressure system (having a relatively low fuel pressure) configured to provide fuel having a defined desired pressure at the inlet of a high pressure pump 108, the high pressure pump 108 configured to increase the fuel pressure, e.g., to inject fuel 103 into the internal combustion engine 110. Method 400 may be carried out by a control device 101 of fuel system 100. The fuel system 100 and the internal combustion engine 110 may be part of a motor vehicle.Method 400 includes detecting 401, on the basis of a measurement signal 202 of low-pressure sensor 107, that a first criterion for the (possible) presence of an impairment of low-pressure sensor 107 is fulfilled. The measurement signal 202 may have been detected during normal operation of the fuel system 100 (without the operation of the fuel system 100 being dedicatedly adapted for checking the low-pressure sensor 107). The measurement signal 202 may include a temporal sequence of measurements 200 of the low pressure sensor 107 (e.g., 50 or more, or 100 or more measurements 200). In the context of checking the first criterion, it is possible to check whether or not the measurement signal 202 has a sufficiently strong oscillation (optionally an oscillation with a defined (pump) frequency). In this case, it is possible in particular to check whether the measurement signal 202 has a vibration which correlates with the operation of the high-pressure pump 108 (in particular which has a frequency which correlates with the pump frequency of the high-pressure pump 108).It is thus possible in a first step (in particular without any influence on the operation of the fuel system 100) to check on the basis of a first criterion whether the low-pressure sensor 105 is possibly impaired.The method 400 further comprises, in response to detecting 401 that the first criterion is fulfilled (in particular only if it has been detected beforehand that the first criterion is fulfilled), checking 402, on the basis of a (dedicated) change of the setpoint pressure 201 of fuel 103 in the low-pressure system, whether the low-pressure sensor 107 (actually) has an impairment. A significant change in the setpoint pressure 201 can be effected for the checking 402 (for example by 5% or more, or by 10% or more). In this case, the low-pressure pump 105 can be caused to adapt the actual pressure in the low-pressure system in accordance with the requested change in the setpoint pressure 201.It can then be checked on the basis of the measured values 200 of the low-pressure sensor 107 whether or not the measured values 200 change in accordance with the requested change in the setpoint pressure 201. In the latter case, it is possible to infer an actual impairment of the low-pressure sensor 107.The measures described in this document can be used to efficiently increase the robustness of the fault detection of the low-pressure sensor 107 of a fuel system 100 of an internal combustion engine 110. In particular, misdiagnoses can be avoided. Further, it is possible to reliably distinguish between the cases of "hanging sensor" and "vapor bubbles in the fuel".The present invention is not limited to the exemplary embodiments shown. In particular, it should be noted that the description and the figures are intended to illustrate, by way of example only, the principle of the proposed methods, apparatuses and systems.

Claims

Device (101) for checking a low-pressure sensor (107) of a low-pressure system of a fuel system (100) for supplying fuel (103) to an internal combustion engine (110); wherein the device (101) is configured to - identify, on the basis of a measurement signal (202) of the low-pressure sensor (107), that a first criterion for the presence of an impairment of the low-pressure sensor (107) is fulfilled; and - identify, on the basis of a change in a setpoint pressure (201) of fuel (103) in the low-pressure system, whether the low-pressure sensor (107) has an impairment.Device (101) according to Claim 1, wherein - the device (101) is configured to analyze a vibration of the measurement signal (202) of the low-pressure sensor (107) in order to check the first criterion for the presence of an impairment of the low-pressure sensor (107); and - the vibration of the measurement signal (202) is effected in particular by a high-pressure pump (108) of the fuel system (100) which is arranged downstream of the low-pressure system.Device (101) according to Claim 2, wherein the device (101) is configured to - determine an indicator (210) for a strength, in particular for an amplitude, of the oscillation of the measurement signal (202); and - check the first criterion for the presence of an impairment of the low-pressure sensor (107) on the basis of the indicator (210) for the strength of the oscillation of the measurement signal (202), in particular in such a way that - the first criterion is detected as being fulfilled if the indicator (210) for the strength of the oscillation of the measurement signal (202) indicates a strength of the oscillation of the measurement signal (202) which is less than a threshold value (211); and / or - the first criterion is detected as not being fulfilled if the indicator (210) for the strength of the oscillation of the measurement signal (202) indicates a strength of the oscillation of the measurement signal (202) which is greater than the threshold value (211).Device (101) according to one of the preceding claims, wherein the device (101) is configured to check the first criterion for the presence of an impairment of the low-pressure sensor (107), - without causing a change in the setpoint pressure (201) of fuel (103) in the low-pressure system for this purpose; and / or - without intervening in an operation of the fuel system (100) for this purpose.Device (101) according to one of the preceding claims, wherein the device (101) is configured to - determine a change in measurement values (200) of the low-pressure sensor (107) caused as a result of the change in the setpoint pressure (201) of fuel (103) in the low-pressure system; and - to check whether the low-pressure sensor (107) has an impairment based on the determined change in measurement values (200) of the low-pressure sensor (107), in particular based on a comparison of the determined change in measurement values (200) of the low-pressure sensor (107) with the caused change in the setpoint pressure (201).Device (101) according to Claim 5, wherein the device (101) is configured to - determine that the low-pressure sensor (107) has an impairment if the ascertained change in measurement values (200) of the low-pressure sensor (107) is smaller in absolute value than a change threshold value; wherein the change threshold value in particular depends on the effected change in the setpoint pressure (201); and / or - determine that the low-pressure sensor (107) has no impairment if the ascertained change in measurement values (200) of the low-pressure sensor (107) is larger in absolute value than the change threshold value.Device (101) according to one of Claims 5 to 6, wherein the device (101) is configured to determine, based on the determined change in measurement values (200) of the low-pressure sensor (107), in particular based on the comparison of the determined change in measurement values (200) of the low-pressure sensor (107) with the effected change in the setpoint pressure (201), whether - the low-pressure sensor (107) has a sticking and / or a limitation of measurement values (200) as impairment; or - the low-pressure sensor (107) has no impairment, and instead the fuel (103) in the low-pressure system has bubbles, in particular vapor bubbles.The device (101) according to any one of the preceding claims, wherein the device (101) is configured to cause a low pressure pump (105) of the fuel system (100) to change an actual pressure of fuel (103) in the low pressure system according to the change of the desired pressure (201).Device (101) according to one of the preceding claims, wherein the device (101) is configured to cause the change of the setpoint pressure (201) of fuel (103) in the low-pressure system for checking the low-pressure sensor (107) only after it has been detected that the first criterion is fulfilled.Device (101) according to one of the preceding claims, wherein - the device (101) is configured to effect at least one measure with respect to the internal combustion engine (110) if it is determined that the low-pressure sensor (105) has an impairment; and - the measure comprises in particular - the output of an indication to a user of the internal combustion engine (110); and / or - an adaptation, in particular a degradation, of the operation of the internal combustion engine (110).Method (400) for checking a low-pressure sensor (107) of a low-pressure system of a fuel system (100) for supplying fuel (103) to an internal combustion engine (110); wherein the method (400) comprises - detecting (401), on the basis of a measurement signal (202) of the low-pressure sensor (107), that a first criterion for the presence of an impairment of the low-pressure sensor (107) is fulfilled; and - in response to detecting (401) that the first criterion is fulfilled, checking (402), on the basis of a change in a setpoint pressure (201) of fuel (103) in the low-pressure system, whether the low-pressure sensor (107) has an impairment.

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