Method and apparatus for determining the fluid injection amount of an injection system

Abstract

The present invention relates to a method and a device for determining a fluid injection quantity of an injection system (100), wherein the injection system (100) has a high-pressure pump (110), a high-pressure region (120) adjacent to the high-pressure pump (110), a pressure sensor (130) and an injector (140), and the injector is fed from the high-pressure region (120), and the method comprises the following steps: - detecting a measurement signal (310) by means of the pressure sensor (130); - separating a first pressure profile (320) from the measurement signal (310), the first pressure profile characterizing the pressure profile before fluid injection by means of the injector (140), and separating a second pressure profile (340) from the measurement signal (310), the second pressure profile characterizing the pressure profile after fluid injection by means of the injector (140); - performing a kernel density estimation by means of the first pressure profile (320) and the second pressure profile (340); - determining a pressure difference (430, 360); - determining the fluid injection quantity by means of the pressure difference (430, 360).

Description

Technical Field

[0001] The present disclosure relates to a method and a device for determining a fluid injection quantity of an injection system, wherein the injection system has a high-pressure pump, a high-pressure region adjacent to the high-pressure pump, a pressure sensor, and an injector, and the injector is fed from the high-pressure region. Background Art

[0002] Injection systems are used to inject fuel, in particular directly, into the combustion chambers of internal combustion engines. Against the background of increasingly stringent consumption and emission standards, new challenges / requirements are posed to the accuracy of fuel metering in the case of these injection systems. The unprocessed engine emissions and the harmful substance conversion of the exhaust gas aftertreatment device of the internal combustion engine are related to the fuel / air ratio in the cylinders of the internal combustion engine. However, the conventional lambda regulation using a broadband lambda sensor between the internal combustion engine and the three-way catalytic converter in the exhaust duct only takes into account the ratio of air to the mass of the injected fuel that globally occurs in the internal combustion engine. Therefore, on the one hand, it is necessary to ensure a uniform distribution of the air quality over the individual cylinders of the internal combustion engine, and on the other hand, it is also necessary to enable an accurate metering of the fuel mass for each cylinder by means of the injection system.

[0003] In order to combust advantageously and to comply with the consumption and emission standards, it is therefore necessary to determine the fluid injection quantity for each cylinder for each working cycle. In the case of conventional injection systems, this takes place by determining the opening and closing time points of the individual valves / injectors based on the control voltage and the control current, and subsequently compensating for possible differences in the hydraulic opening duration by adapting the unique electrical control duration of the injector. However, these conventional injection systems do not take into account deviations in the unique flow behavior of the injector that may occur during the service life of the injector, for example due to manufacturing tolerances or nozzle / injector coking. Summary of the Invention

[0004] Therefore, the object of the present disclosure is to provide a method and a device by means of which it is possible to reliably and accurately determine the fluid injection quantity of an injection system.

[0005] This object is solved by the features of the independent patent claims. Advantageous designs of the present disclosure are described in the dependent claims.

[0006] According to the present disclosure, a method for determining the fluid injection quantity of an injection system has the following steps, wherein the injection system has a high-pressure pump, a high-pressure region adjacent to the high-pressure pump, a pressure sensor, and an injector, and the injector is fed from the high-pressure region:

[0007] - During operation of the injection system, a measurement signal is detected using a pressure sensor, wherein the measurement signal characterizes the fluid pressure in the high-pressure region;

[0008] - A first pressure change process is segmented from the measurement signal, the first pressure change process characterizing the pressure change process before fluid injection using an injector, and a second pressure change process is segmented from the measurement signal, the second pressure change process characterizing the pressure change process after fluid injection using an injector;

[0009] - Kernel density estimation is performed using the first pressure change process and the second pressure change process to determine a first probability density function before fluid injection and a second probability density function after fluid injection;

[0010] - A pressure difference is determined from the first probability density function and the second probability density function;

[0011] - The fluid injection quantity is determined by means of the pressure difference.

[0012] The high-pressure pump of the injection system is configured to bring the fluid / fuel to a predefined pressure and convey it into the high-pressure region, and to maintain / control the predefined pressure in the high-pressure region by re-pumping the fluid / fuel. One injector or multiple injectors of the injection system are configured to inject the fluid / fuel from the high-pressure region into the cylinders of an internal combustion engine. Due to this injection, the pressure in the high-pressure region decreases. The pressure sensor of the injection system according to the present disclosure is configured to detect the pressure change process of the pressure in the high-pressure region. Thus, the pressure increase caused by the conveyance of the high-pressure pump or the pressure decrease caused by the injection of the injector is detected and can be seen in the measurement signal of the pressure sensor.

[0013] According to the present disclosure, the measurement signal of the pressure sensor is detected during operation of the injection system, wherein the measurement signal characterizes the fluid pressure in the high-pressure region. Thus, the injection of the fluid / fuel by the injector is visible in the measurement signal, and additionally the supply of the fluid / fuel to the high-pressure region by the high-pressure pump is also visible.

[0014] According to the present disclosure, in another step, a first pressure change process is segmented from the measurement signal, where the first pressure change process characterizes the pressure change process before fluid injection using an injector. Thus, during the first pressure change process, no fuel injection occurs from the high-pressure region, so that the pressure in the high-pressure region remains constant. Additionally, according to one embodiment, no pressure increase caused by introducing fuel into the high-pressure region by means of a high-pressure pump occurs. According to the present disclosure, furthermore, a second pressure change process is segmented from the measurement signal, where the second pressure change process characterizes the pressure change process after fluid injection using an injector. Thus, fluid injection has occurred and the pressure in the high-pressure region has decreased due to the fluid injection.

[0015] According to the present disclosure, in another step, kernel density estimation is performed using the first pressure change process and the second pressure change process, where a first probability density function and a second probability density function are determined therefrom. The first probability density function is the function before fluid injection using an injector, while the second probability density function is the density function after fluid injection using an injector. During this step, precisely the first pressure change process and the second pressure change process are processed by means of kernel density estimation, so that the pressure occurring during this time interval can be better read from the measured pressure change process. Kernel density estimation provides a distribution function with a maximum value. Compared to a simple mean calculation, this method is robust with respect to the addition of additional pressure values, which may also include outliers or values not on the average, if necessary. Such additional pressure values may occur, for example, during fuel delivery by a high-pressure pump or during additional injections.

[0016] According to the present disclosure, in another method step, a pressure difference is determined from the first probability density function and the second probability density function. As already mentioned, the first probability density function and the second probability density function provide distribution functions with corresponding maximum values. According to one embodiment, the corresponding pressure differences during the time interval before fluid injection using an injector and after fluid injection using an injector or between the time interval before fluid injection using an injector and the time interval after fluid injection using an injector can be determined by forming the difference between the maximum values.

[0017] According to the present disclosure, in another step, the fluid injection amount is determined by means of the determined pressure difference. The fluid injection amount during fluid injection through an injector can be determined by means of the known volume of the high-pressure region, the speed of sound, and precisely the determined pressure difference. According to the present disclosure, in particular, since kernel density estimation is implemented using the first pressure change process and the second pressure change process, the pressure difference can be advantageously and accurately determined. Since the pressure difference can be advantageously and accurately determined, the fluid injection amount can then also be advantageously and accurately determined by means of the accurately determined pressure difference. The high-pressure volume of the injection system is predefined by the geometry of the injection system and is determinable or known. Generally speaking, according to the present disclosure, the fluid injection amount can be advantageously and accurately determined, whereby the internal combustion engine can be advantageously operated and the specified emissions can be complied with.

[0018] The analytical mathematical relationship between the injected fluid amount and the pressure drop is determined according to the following equation, where V is the volume of the high-pressure region, Δp is the pressure difference, c is the speed of sound, and m f is the injected fluid amount.

[0019]

[0020] According to the present disclosure, the pressure difference can be advantageously and accurately determined by means of kernel density estimation, such that the injected fluid amount can be advantageously and accurately determined in the case of a constant volume and a constant speed of sound in the high-pressure region.

[0021] According to one embodiment, the maximum value of the first probability density function and the maximum value of the second probability density function are determined, and the pressure difference is determined by means of the two maximum values. The probability density function is a function similar to a Gaussian curve / normal distribution with a peak / maximum value. This maximum value represents the average pressure during the time interval before fluid injection or during the time interval after fluid injection. Therefore, the pressure difference between the time interval before fluid injection and the time interval after fluid injection through the injector can be very accurately determined by forming the difference according to the two maximum values. According to this embodiment, the pressure difference can be advantageously and accurately determined, whereby the fluid injection amount can in turn be advantageously and accurately determined and the internal combustion engine can be advantageously operated.

[0022] According to one embodiment, system constants are provided and the system constants are taken into account when determining the fluid injection amount. According to this embodiment, the system constants take into account the geometry-related parameters of the injection system. According to one embodiment, the geometry-related parameters of the injection system are, for example, the volume of the high-pressure region, i.e., the volume in which the fuel / fluid is held under high pressure. According to one embodiment, the system constants can additionally have a proportionality constant that takes into account the relationship between the natural frequency and the speed of sound in the high-pressure region.

[0023] An analytical mathematical relationship between the amount of fluid injected and the pressure drop with the aid of system constants is determined according to the following equation, where m f is the amount of fluid injected, k sys is the system constant, Δp is the pressure difference, and f is the natural frequency.

[0024]

[0025] According to this embodiment, all system constants, in particular the volume of the high-pressure region and the proportionality constant for the relationship between the natural frequency and the speed of sound, are combined in the system constant k sys .

[0026] According to one embodiment, a variable speed of sound is determined from the geometry of the high-pressure region and the natural frequency of the standing wave excited by the pumping conveyance through the high-pressure pump and the fluid injection of the injector. The variable speed of sound thus determined is taken into account when determining the amount of fluid injection. The speed of sound is an important parameter for precisely determining the amount of fluid injection. The speed of sound is associated with the pressure and temperature of the fluid in the high-pressure region. The pumping conveyance through the high-pressure pump, i.e., by increasing the pressure in the high-pressure region and the fluid injection by the injector, excites a standing wave in the high-pressure region. The standing wave has a natural frequency that can be determined, and this natural frequency can in turn be used (einflieβen) in the determination of the variable speed of sound. The duration required for the wave to pass through the high-pressure region or the relationship between the hydraulic natural frequency and the speed of sound depends on the geometry of the high-pressure region. According to one embodiment, the excited standing wave can be determined from the measurement signal of the pressure sensor. Thus, according to this embodiment, the natural frequency can be determined from the measurement signal of the pressure sensor, from which in turn the variable speed of sound can be determined, and the variable speed of sound is used to determine the amount of fluid injection of the injector. Additionally, the fluid injection can thereby be advantageously precisely implemented.

[0027] According to one embodiment, the natural frequency is determined from a part of the measurement signal of the pressure sensor by means of a fast Fourier transform. In the case of an increase in pressure and a decrease in temperature in the high-pressure region, the determined natural frequency increases proportionally with the speed of sound. Thus, the natural frequency is related to the pressure in the high-pressure region and the temperature in the high-pressure region. According to one embodiment, the temperature can be determined by a temperature sensor and the pressure can be determined from the measurement signal of the pressure sensor by means of the pressure sensor. According to another embodiment, the temperature can be determined by means of a characteristic curve family that is determined at the test bench with the aid of a test fuel (e.g., n-heptane). However, according to another embodiment, since the pressure oscillation is evaluated by means of a fast Fourier transform, it is no longer necessary to determine the temperature. Overall, the fast Fourier transform provides a valid value for the natural frequency, from which in turn the amount of fluid injection can be advantageously precisely determined.

[0028] According to one embodiment, a triangular kernel and / or a predetermined bandwidth is used in kernel density estimation, where the bandwidth is preferably from 0.5 bar to 1 bar. Using the triangular kernel can facilitate fast calculation, whereby the method can be executed in real time and on embedded hardware (such as an engine control device). As the bandwidth increases, the resulting probability density function is smoothed in an enhanced manner. According to another embodiment, a normal distribution is used as the kernel in kernel density estimation.

[0029] According to one embodiment, an injection system has a plurality of injectors in the injector, each of which is fed from the high-pressure region, where for each of the injectors, an injector-specific pressure change process is segmented from the measurement signal, and a first probability density function and a second probability density function are determined respectively, and a corresponding pressure difference is determined for each of the injectors, and a corresponding fluid injection amount is determined for each of the injectors by means of the corresponding pressure difference. According to this embodiment, the injection system has a plurality of injectors that inject fluid from the high-pressure region, for example, in a cylinder, respectively. According to one embodiment, the injection is carried out in a time-staggered manner so that the necessary injector-specific pressure change processes can be segmented from the measurement signal of the pressure sensor and assigned. Subsequently, the corresponding first probability density function and second probability density function belonging to the injector can be determined from these injector-specific pressure change processes by means of corresponding kernel density estimation. Subsequently, a corresponding pressure difference can be determined for each of the injectors from these probability density functions. From these injector-specific pressure differences, the injector-specific fluid injection amount can be determined for each injector of the injection system according to the corresponding pressure difference. Thus, for an injection system with a plurality of injectors, an accurate fluid injection amount can be determined for each individual injector. According to another embodiment, the accurate fluid injection amount can be compared with a predefined necessary fluid injection amount for optimally operating the internal combustion engine, and can be increased or decreased by means of controlling the injector to achieve the predefined fluid injection amount. Thus, an accurate fluid injection amount can be advantageously and precisely determined for each injector, and thereby the operation of the internal combustion engine can be advantageously implemented.

[0030] According to one embodiment, the determined fluid injection amount is compared with a predetermined injection amount, and as long as the determined fluid injection amount deviates from the predetermined injection amount, the control of the injector is adapted.

[0031] According to another embodiment, a device for determining the fluid injection quantity of an injection system has a control unit, wherein the injection system has a high-pressure pump, a high-pressure region adjacent to the high-pressure pump, a pressure sensor, and an injector, and the injector is fed from the high-pressure region, and the control unit is configured to control the above method. The device can be, for example, an engine control unit. It is also conceivable that the device is part of an engine control unit or is installed as an additional control unit, for example, in a vehicle having an injection system. Description of the Drawings

[0032] Embodiments and improvements of the method and device according to the present disclosure are shown in the drawings and are described in more detail according to the following description.

[0033] Figure 1 A schematic diagram showing an injection system having a control unit according to an embodiment is shown.

[0034] Figure 2 A first pressure change process chart according to the first embodiment is shown.

[0035] Figure 3 A first kernel density estimation chart according to the first embodiment is shown.

[0036] Figure 4 A second pressure change process chart according to the second embodiment is shown.

[0037] Figure 5 A second kernel density estimation chart according to the second embodiment is shown.

[0038] Figure 6 A chart according to the first embodiment is shown, in which the fast Fourier transform is performed on three different pressure change processes.

[0039] Figure 7 A correlation chart according to the first embodiment is shown. Detailed Description of the Embodiment

[0040] Figure 1 A schematic diagram showing, for example, an injection system 100 for an internal combustion engine is shown. The injection system 100 has a high-pressure pump 110, a high-pressure region 120, a pressure sensor 130, and a plurality of injectors 140. Figure 1Additionally shown is a control unit 200, which is configured to control an injection system 100. During operation of the injection system 100, a fluid is conveyed from a fluid reservoir (not shown) into a high-pressure region 120 by means of a high-pressure pump 110, whereby the pressure of the fluid is additionally increased to a desired pressure by means of the high-pressure pump 110. The high-pressure region 120 has a rail that is connected to or feeds fluid to an injector 140. The control unit 200 actuates the injector 140, whereby the fluid is injected from the high-pressure region 120 into, for example, a combustion chamber of an internal combustion engine for combustion. A pressure sensor 130 detects a measurement signal 310 (shown in Figure 2 ), which characterizes the pressure profile of the pressure in the high-pressure region 120. The pressure sensor 130 transmits the measurement signal 310 to the control unit 200, which in turn processes the measurement signal 310 and controls the injection system 100 based on the result.

[0041] Figure 2 Shown is a first pressure profile chart 300. In the first pressure profile chart 300, the measurement signal 310 of the pressure sensor 130 is plotted over time. The measurement signal 310 is divided into a first pressure region 320, an injection region 330, a second pressure profile 340, and a pump region 350. The first pressure profile 320 represents the profile of the pressure signal before injection through the injector 140. The injection region 330 represents the profile of the measurement signal 310 during injection through the injector 140. In this case, it can be seen that the pressure in the high-pressure region 120 drops due to injection through the injector 140. The second pressure profile 340 represents the profile of the measurement signal 310 after injection through the injector 140 and before the pumping phase in which the fluid is introduced into the high-pressure region 120 by means of the high-pressure pump 110. The pump region 350 of the measurement signal 310 represents the profile of the measurement signal 310 during the pumping phase. Here, it can be seen that the pressure in the high-pressure region 120 increases due to the introduction of the fluid into the high-pressure region 120 by means of the high-pressure pump 110. Additionally shown in Figure 2 is a pressure difference 360 between the first pressure profile 320 and the second pressure profile 340. Since the control unit 200 actuates / controls the injector 140 itself, the time required for segmentation is known. Thereby, the measurement signal 310 of the pressure sensor 130 can be advantageously segmented simply and precisely. Additionally, the method is robust against relatively small time offsets.

[0042] Figure 3A first kernel density estimation graph 400 is shown, in which a first probability density function 410 and a second probability density function 420 are shown in the first kernel density estimation graph 400. Using kernel density estimation, the pressure value with the statistically highest residence probability should be determined. In order to determine the pressure value within the first pressure change process or the second pressure change process, that is, during the plateau phase before or after injection, that is, during the phase with a relatively constant pressure in the injection system 100. Therefore, the first probability density function 410 has a first maximum value, that is, a first pressure level 430 before injection through the injector 140. The second probability density function 420 has a second maximum value, that is, a second pressure level 440 after injection through the injector. The first pressure level 430 and the second pressure level 440 are shown in Figure 3 It is shown. From these pressure levels 430, 440, the pressure difference 450 that has occurred due to injection through the injector 140 can be advantageously and accurately determined. The method is advantageously robust with respect to transient extreme values (such as transient high or low pressure values).

[0043] Figure 4 A second pressure change process graph 500 is shown. In the second pressure change process graph 500, a first pressure change process 510, a second pressure change process 520, and a third pressure change process 530 in bar are shown over time. The first pressure change process 510 starts at approximately 355 bar and first extends constantly until the time point at which the pressure decreases to approximately 345 bar due to injection through the injector 140, and then immediately afterwards the pressure extends constantly until the pressure increases due to the pumping phase. The second pressure change process 520 first starts at approximately 352 bar, then extends constantly, then decreases to approximately 347 bar due to injection, then remains constant, and then increases again due to the pumping phase. The third pressure change process 530 starts at approximately 351 bar, then extends constantly, slightly decreases to 350 bar due to less injection, and then extends constantly. In Figure 4 it is shown that the pressure change process is divided into pre-injection and post-injection according to the line width. The thicker line width represents the pressure change process before the corresponding injection, while the thinner line width represents the pressure change process after the corresponding injection through the injector 140.

[0044] Figure 5A kernel density estimation graph 600 is shown, which shows a first probability density function 610 for the first pressure change process 510, a second probability density function 620 for the first pressure change process 510, a first probability density function 630 for the second pressure change process 520, a second probability density function 640 for the second pressure change process 520, a first probability density function 650 for the third pressure change process 530, and a second probability density function 660 for the third pressure change process 530. The first probability density functions 610, 630, 650 respectively represent the probability density functions before injection through the injector 140 here. The second probability density functions 620, 640, and 660 represent the probability density functions after injection through the injector here. Figure 5 Additionally, a first pressure difference 670, a second pressure difference 680, and a third pressure difference 690 are shown. The first pressure difference 670 is the difference between the maximum values of the first probability density function 610 and the second probability density function 620 of the first pressure change process 510. The second pressure difference 680 is the difference between the maximum values of the first probability density function 630 and the second probability density function 640 of the second pressure change process 520. The third pressure difference is the difference between the maximum values of the first probability density function 650 and the second probability density function 660 of the third pressure change process 530. Therefore, the pressure difference of each injection through the injector can be advantageously determined simply and precisely based on the determined maximum value / peak.

[0045] Figure 4 and 5 It is shown that, according to this embodiment, simply dividing the measurement signal of the pressure sensor into segments before injection and segments after injection is sufficient to achieve an advantageously good and precise determination of the fluid injection amount due to the good robustness of this method.

[0046] Figure 6A diagram showing a pressure variation process that has been transformed by means of a fast Fourier transform (FFT) is presented. In diagram 700, a first FFT pressure variation process 710 at 250 bar, a second FFT pressure variation process 720 at 300 bar, and a third FFT pressure variation process 730 at 350 bar are shown. The frequency in Hertz is shown on the X-axis. The amplitude in units of [bar] is shown on the Y-axis. Diagram 700 shows the pressure variation process at a constant temperature. The peaks of the variation process represent different oscillation modes. It can be seen from this diagram how the natural frequencies of the individual oscillation modes increase as the pressure increases. The higher the pressure, the more the peaks shift to the right. This can be attributed to the increase in the speed of sound of the fluid due to the increased pressure. In an inferential manner, the speed of sound can be determined from the pressure. This is in turn used in the determination of the injection quantity. Thereby, the accuracy of the injection quantity determination can be further improved additionally.

[0047] Figure 7 A related diagram 800 is shown. Each point in the related diagram 800 corresponds to an individual injection for which the pressure, temperature, and injection duration in the high-pressure region have been changed. The injection quantity measured with the measurement system Akribis is shown on the X-axis, and the injection quantity determined using the method according to the present disclosure is shown on the Y-axis. Akribis is an injection quantity measurement system that determines the injection quantity with the aid of a test bench. Here, this involves a piston (one for each injector) that is deflected due to the injection. The mass injected can be determined very precisely by means of the piston area, the deflection, and the density of the test medium. This type of measurement system is called a quantity indicator. Alternatively thereto, there are also pressure indicators (such as Mexus 2.0) or tube indicators (Rohrindiktor). According to this related diagram, a system constant is prescribed once for the injection system being examined and thus for the entire data set. The system constant is determined by means of regression. It can thus be seen from the related diagram 800 that the determination of the fluid injection quantity according to the present method is advantageously in precise agreement with the quantity of the actual injection determined by the measurement series.

Claims

1. A method for determining a fluid injection quantity of an injection system (100), wherein the injection system (100) has a high-pressure pump (110), a high-pressure region (120) adjacent to the high-pressure pump (110), a pressure sensor (130) and an injector (140), and the injector is fed from the high-pressure region (120), and the method has the following steps: - Detecting a measurement signal (310) by means of the pressure sensor (130) during operation of the injection system (100), wherein the measurement signal (310) characterizes the fluid pressure in the high-pressure region (120); - Segmenting out a first pressure change process (320) from the measurement signal (310), the first pressure change process characterizing the pressure change process before fluid injection by means of the injector (140), and segmenting out a second pressure change process (340) from the measurement signal (310), the second pressure change process characterizing the pressure change process after fluid injection by means of the injector (140); - Performing kernel density estimation by means of the first pressure change process (320) and the second pressure change process (340) to determine a first probability density function (410) before the fluid injection and a second probability density function (420) after the fluid injection; - Determining a pressure difference (430, 360) from the first probability density function (430) and the second probability density function (440); - Determining the fluid injection quantity by means of the pressure difference (430, 360).

2. The method according to claim 1, wherein the maximum value of the first probability density function (410) and the maximum value of the second probability density function (420) are determined, and the pressure difference (430, 360) is determined by means of the two maximum values.

3. The method according to claim 1 or 2, wherein system constants are provided and taken into account when determining the fluid injection quantity, and the system constants take into account geometric parameters of the injection system (100).

4. The method according to claim 1 or 2, wherein a variable speed of sound is determined from the geometry of the high-pressure region (120) and the natural frequency of a standing wave excited by the pumping conveyance through the high-pressure pump (110) and the fluid injection of the injector (140), and this variable speed of sound is taken into account when determining the fluid injection quantity.

5. The method according to claim 4, wherein the natural frequency is determined from a part of the measurement signal (310) by means of a fast Fourier transform.

6. The method according to claim 1 or 2, wherein a triangular kernel and / or a predetermined bandwidth are used during the kernel density estimation.

7. The method according to claim 6, wherein the bandwidth is from 0.5 bar to 1 bar.

8. The method according to claim 1 or 2, wherein the injection system (100) has a plurality of injectors in the injector (140), and the injectors are respectively fed from the high-pressure region (120), wherein for each of the injectors (140), an injector-unique pressure change process (320, 340) is segmented from the measurement signal (310), and a corresponding first probability density function (410) and a corresponding second probability density function (420) are determined, and for each of the injectors (140), a corresponding pressure difference (430, 360) is determined and for each of the injectors (140), a corresponding fluid injection amount is determined by means of the corresponding pressure difference (430, 360).

9. The method according to claim 1 or 2, wherein the determined fluid injection amount is compared with a predetermined injection amount, and as long as the determined fluid injection amount deviates from the predetermined injection amount, the control of the injector (140) is adapted.

10. A device for determining the fluid injection amount of an injection system (100), wherein the injection system (100) has a high-pressure pump (110), a high-pressure region (120) adjacent to the high-pressure pump (110), a pressure sensor (130) and an injector (140), and the injector is fed from the high-pressure region (120), wherein the device has a control unit (200), and the control unit is configured to control the method according to any one of claims 1 to 9.

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