Method for providing a measurement and / or control signal of an internal combustion engine

Abstract

The invention relates to a method (100) for providing a measurement and / or control signal of an internal combustion engine (11), in particular of a motor vehicle (10), comprising steps of acquiring a signal (S), storing a first value of the signal (S) in a memory (21), storing a second value of the signal (S) or a further value of the signal (S) in the memory (21), determining an output signal by interpolating at least two stored values ​​of the signal (S), and outputting the output signal

Description

[0001] The invention relates to a method for providing a measurement and / or control signal of an internal combustion engine, comprising steps of detecting a signal, storing a first value of the signal in a memory, storing a second value of the signal or a further value of the signal in the memory, determining an output signal by interpolating at least two stored values ​​of the signal, and outputting the output signal. Furthermore, the invention relates to a control device.

[0002] In motor vehicles, data or signals, particularly measurement data, from multiple measuring devices are often combined in order to make statements about processes occurring in the vehicle, for example, using on-board calculation. In this case, signals from different measuring devices may be made available to a calculation or processing device at different times, so a delay in signal provision may be necessary to ensure the accuracy of the evaluation results. Such different data provision may be based, for example, on the type of measurement data acquisition, the length of the signal line, and / or other factors.

[0003] For time synchronization, it is common practice to delay data transmission or provision by temporarily storing it. However, resources, especially the storage capacity of control units, are limited, and increasing such resources would lead to increased costs, particularly for the control unit itself. Because storage requirements increase with fast time intervals, especially with long delay times, a loss of accuracy can occur if signal values ​​are deleted, ignored, or skipped.

[0004] Against this background, it is an object of the invention to improve the provision of a measurement and / or control signal of an internal combustion engine. In particular, the provision of a measurement signal of an internal combustion engine is to be improved in order to enable a determination of emission values ​​of the internal combustion engine with reduced memory space.

[0005] This problem is solved by a method for providing a measurement and / or control signal of an internal combustion engine with the features of claim 1 and a control device for a motor vehicle with the features of claim 12. The dependent claims relate to advantageous embodiments of the invention.

[0006] According to a first aspect, a method for providing a measurement and / or control signal of an internal combustion engine is specified, comprising steps of acquiring a signal; storing a first value of the signal in a memory; storing a second value of the signal or a further value of the signal in the memory if a slope of the signal changes; determining an output signal by interpolating at least two stored values ​​of the signal; and outputting the output signal.

[0007] This reduces the number of values ​​that need to be stored, as these values ​​are only saved when the signal changes or its slope changes. To generate the output signal, the signal, or a time-based representation of a signal, can be interpolated from the stored values ​​of the signal—that is, as a straight line or a series of such lines connecting the at least two stored values. This allows for an output signal that is at least approximately a realistic representation of the captured signal and can be made available elsewhere for further processing.

[0008] A signal within the meaning of the present invention is in particular time-varying and / or is in particular an electrical output signal of a measuring device, a processing device and / or a control device in the form of a digital signal.

[0009] In the course of the process, a signal, in particular a signal from a suitable measuring device or sensor, is first acquired. Such a signal is acquired, in particular, in a time-dependent and / or continuous manner, whereby, in particular, each time value can be assigned a signal value, in particular a measured or acquired value. When acquiring the signal, in particular, an initial value of the signal is first stored in a memory or buffer, which can be used as the basis for determining the output signal.

[0010] In particular, with the help of an algorithm, the signal can be analyzed and a gradient of the signal or the time-based signal curve can be determined. The determination of the gradient of the signal can in particular be carried out continuously, for each time value or at specific time intervals. If the gradient of the signal or a (mathematical) derivative of the signal changes over its time course, this is typically associated with a change in the value of the detected signal. Such a value of the signal or changed value of the signal is filed or saved, in particular at the time at which a change in the gradient of the signal is determined, and thus kept available for further processing within the framework of the method. In this case, it can be provided that a value of the signal is only filed if a change in the gradient exceeds a predetermined threshold.This allows individual signal values ​​to be stored without having to record or store the entire signal curve. This eliminates the need to store data during periods without signal or value changes, particularly intermediate values ​​between stored values, thus reducing storage space requirements. This can lead to cost reductions for storage devices and control systems.

[0011] To obtain a representation of the signal as an output signal, at least two stored values ​​can be interpolated, particularly depending on accuracy requirements, to create a relationship with a corresponding slope between the values. This allows the output signal, or a temporal sequence of the signal, to be determined in the form of a curve or function, which can then be output and used, in particular, for further processing in or on a control unit or processing device.

[0012] According to another aspect, a control device for a motor vehicle is proposed, wherein the control device is configured to detect a signal, to store a first value of a signal in a memory, to store a second value of the signal or a further value of the signal in the memory if a slope of the signal changes, to determine an output signal by interpolating at least two stored values ​​of the signal and to output the output signal.

[0013] In this case, the control device can be configured to detect at least one signal from a measuring device and / or a signal generated by the control device or another control device and / or can have the memory or a memory unit. Such a control device can, for example, be a control device of an internal combustion engine of a motor vehicle, which is configured to detect emission values ​​of the internal combustion engine based on detected measured values ​​in the form of signals and, in particular, to process them within the framework of a method described herein.

[0014] A combustion engine typically undergoes a multitude of physical processes, which can be continuously recorded and / or evaluated, particularly for control and / or operational optimization. For this purpose, it may be necessary to provide the recorded data or signals to an evaluation unit or control device at a coordinated time to enable unbiased determination of results.

[0015] The invention is based, among other things, on the idea of ​​analyzing a signal in the sense of a mathematical function and, in particular, determining and storing meaningful points of such a function. For this purpose, the derivative of the signal, and thus its slope, is determined, with a value of the signal being stored at points where the slope changes. These stored values ​​are then used to construct a mathematical function that at least approximately represents the originally acquired signal. To this end, the stored points or values ​​are converted back into a function, and thus a curve or the output signal. By interpolating between two points, the relationship between the two values ​​can be determined, and by combining various, especially sequential, sections, a continuous, especially time-based, output signal can be generated.This makes it possible, for example, to determine the emission values ​​of the combustion engine with reduced memory space.

[0016] In one embodiment, the output signal is determined with a time delay. This delayed determination can compensate for a time offset between signals to be evaluated or provided, whereby the signals can be made available simultaneously to a processing device or for processing by subsequent algorithms, in particular in or on the control device or another control device.

[0017] In one embodiment, a time delay for determining the output signal can be specified. This determination can be variable, particularly depending on at least one other definable parameter, such as an operating point of an internal combustion engine, to improve the flexibility and / or accuracy of a subsequent evaluation process. In some embodiments, the time delay can be variable, and in particular variable within predetermined limits, to enable flexibly adaptable evaluation.

[0018] In one embodiment, the signal value and a corresponding acquisition time value are stored as a value pair. This allows for a unique assignment of the signal to a specific acquisition time, thereby determining or defining a temporal sequence of the values. Such an acquisition time value can, for example, be implemented as an increment timestamp.

[0019] In one embodiment, two signal values ​​are interpolated using consecutively stored acquisition time values. This allows the sequence of the stored values ​​to be taken into account when determining the output signal. In particular, two adjacent acquisition time values ​​are interpolated to form the shortest possible connecting line between two stored values ​​and thus keep the output signal as close as possible to the acquired signal. In some embodiments, it may be useful to interpolate non-adjacent acquisition time values ​​or associated signal values ​​to enable averaging for the signal. This can provide an adaptation of the output signal in a suitable application.

[0020] In one embodiment, the signal is a measurement signal from a sensor. A measurement signal is, in particular, a signal comprising a measured quantity acquired by means of a transducer, which can, for example, determine a physical quantity as a multiple of its unit. Such a transducer or sensor can be part of a measuring instrument and / or a measuring device that responds directly to the respective measured quantity.

[0021] In one embodiment, the signal is a modulated signal from a control device. A control signal is, in particular, a signal that includes (control) information from a control device, which is or can be transmitted to at least one receiver. The signal can, in particular, be a composite and / or modulated control signal. Such a signal can, in particular, be manipulated by means of an algorithm and can be based on a measurement signal and / or include corresponding information.

[0022] In one embodiment, the storage device is a ring buffer. A ring buffer is, in particular, a method or device configured to carry out a process in which data or values ​​are continuously stored in a storage unit, especially one of fixed size. If a delay time is exceeded for stored data, this data can be deleted and new data stored. This can result in data or values ​​being available only for a limited period. The method proposed herein can reduce the number of data or values ​​to be stored, thus improving the utilization of a ring buffer, especially one with reduced storage capacity.

[0023] In one embodiment, the signal is a measurement signal from an internal combustion engine. Here, a measured variable from the internal combustion engine can be acquired by a measuring device in or on the internal combustion engine and communicated by this measuring device to the control device so that it can be acquired by the control device as a signal.

[0024] In one embodiment, the measurement signal includes, in particular, information concerning or as a measured quantity an intake air mass, an injection mass, an engine speed, and / or a measured value from a lambda sensor of the internal combustion engine. The measured quantities or measurement signals of the internal combustion engine may exhibit a variable transmission time between acquisition and transmission to a processing or control unit, which may be due, for example, to variability in the flow velocity of a medium, the mass flow rate of the medium, and / or the length of a transmission path. The proposed method can compensate for such a time delay between these exemplary signals, so that they can be made available for further processing simultaneously.

[0025] In one embodiment, the time delay for determining the output signal is predetermined depending on an operating point of the internal combustion engine. Since a time offset of signals, for example, including information about intake air mass, injection mass, and / or measured values ​​from the lambda sensor, can be up to three seconds depending on the engine operating point, an adjustment of the time delay is determined depending on the operating point in order to compensate for this deviation. This can improve the provision of a measurement and / or control signal from an internal combustion engine for further processing, for example, in the context of determining the internal combustion engine's emissions value.

[0026] Further advantages and application possibilities of the invention will become apparent from the following description in conjunction with the figures. Fig. 1 shows a schematic representation of a motor vehicle comprising an embodiment of a control device according to the invention for a motor vehicle. Fig. 2 shows a schematic flow diagram of an embodiment of a method according to the invention for providing a measurement and / or control signal of an internal combustion engine.

[0027] Fig. Figure 1 shows a motor vehicle 10 having a control device 20 according to the invention for a motor vehicle 10 according to an embodiment of the present invention in a schematic representation.

[0028] The motor vehicle 10 has an internal combustion engine 11, which is configured to provide torque for a drive or drivetrain of the motor vehicle 10. This internal combustion engine 11 has at least one measuring device 12, which is configured to detect a measured quantity and output a measurement signal S, in particular one that characterizes this measured quantity.

[0029] In addition, the motor vehicle 10 has the control device 20, which is configured to detect the signal S, to store a first value of the signal S in a memory 21 of the control device 20. The control device 20 is further configured to determine a gradient of the signal S or to form a derivative of the signal S and to store a second value of the signal S or a further value of the signal S in the memory 21 if a gradient of the signal S changes. In addition, the control device 20 is configured to determine an output signal by interpolating at least two stored values ​​of the signal S and to output the output signal and, in particular, to further process this output signal.

[0030] In Fig. Figure 2 shows a schematic flowchart of an exemplary procedure 100 for providing a measurement and / or control signal of an internal combustion engine 11.

[0031] In a first step, a measurement signal S from an internal combustion engine 11 of a motor vehicle 10 is acquired by means of a control device 20. The measurement signal S can, for example, represent or include a measured quantity such as intake air mass, injection mass, and / or a measured value from a lambda sensor of the internal combustion engine 11. In a second step, a first value of the measurement signal S and a corresponding acquisition time value are stored as a value pair in a memory 21 of the control device 20, which is configured as a ring buffer.

[0032] In a step c, a second value of the signal of the measurement signal S and an associated acquisition time value are stored as a second value pair in the memory 21 if a gradient of the measurement signal S changes. In an optional further step, another value of the measurement signal S and an associated acquisition time value can be stored as another value pair in the memory 21 if a gradient of the measurement signal S changes again. This optional step can be repeated as often as desired, and in particular with each gradient change or when a threshold value of a gradient change is exceeded.

[0033] In a step d, an output signal is determined by interpolating at least two stored values ​​of the measurement signal S, and in a further step e, the output signal is output. The output signal can be determined with a time delay, with the time delay for determining the output signal being specified as a function of an operating point of the internal combustion engine 11.

[0034] In an optional step f, the output signal can be further processed with additional data and / or signals, in particular by means of the control device 20, for example used or utilized to determine emission values ​​of the internal combustion engine 11. LIST OF REFERENCE SYMBOLS 10 motor vehicle 11 Internal combustion engine 12 Measuring device 20 Control device 21 storage 100 procedures S Signal af steps

Claims

[1] Method (100) for providing a measurement and / or control signal of an internal combustion engine (11), comprising the following steps: a) detecting a signal (S); b) storing a first value of the signal (S) in a memory (21); c) storing a second value of the signal (S) or a further value of the signal (S) in the memory (21) when a slope of the signal (S) changes; d) determining an output signal by interpolating at least two stored values ​​of the signal (S); and e) Outputting the output signal. [2] Method (100) according to the preceding claim, wherein the output signal is determined with a time delay. [3] Method (100) according to one of the preceding claims, wherein a time delay for determining the output signal can be specified. [4] Method (100) according to one of the preceding claims, wherein the value of the signal (S) and an associated acquisition time value are stored as a value pair. [5] Method (100) according to one of the preceding claims, wherein two values ​​of the signal (S) are interpolated with successively stored acquisition time values. [6] Method (100) according to one of the preceding claims, wherein the signal (S) is a measurement signal of a sensor. [7] Method (100) according to one of the preceding claims, wherein the signal (S) is a signal from a control device. [8] Method (100) according to one of the preceding claims, wherein the memory (21) is a ring buffer. [9] Method (100) according to one of the preceding claims, wherein the signal (S) is a measurement signal of an internal combustion engine (11). [10] Method (100) according to the preceding claim, wherein the measurement signal (S) comprises an intake air mass, an injection mass, an engine speed and / or a measured value of a lambda probe of the internal combustion engine (11). [11] Method (100) according to one of the two preceding claims, wherein the time delay for determining the output signal can be predetermined as a function of an operating point of the internal combustion engine (11). [12] Control device (20) for a motor vehicle (10), wherein the control device (20) is configured to detect a signal (S), to store a first value of the signal (S) in a memory (21), to store a second value of the signal (S) or a further value of the signal (S) in the memory (21) when a gradient of the signal (S) changes, to determine an output signal by interpolating at least two stored values ​​of the signal (S) and to output the output signal.

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