A fuel injection pulse width calculation method, device and storage medium

Abstract

The application relates to an oil injection pulse width calculation method and device and a storage medium. A sampling value of an electromagnetic valve current signal exceeding a preset threshold value is taken as a starting moment of an oil injection control signal. An effective waveform segment of the electromagnetic valve current signal is obtained based on the starting moment of the oil injection control signal, and the data length of the effective waveform segment is determined. A calibration quantity is determined under a set calibration condition, a pulse width type is determined according to the data length of the effective waveform segment and the calibration quantity, wherein the calibration quantity comprises a first calibration quantity and a second calibration quantity. The ending moment of the oil injection control signal is determined according to the pulse width type, and the oil injection pulse width is determined based on the starting moment and the ending moment of the oil injection control signal and a preset correction quantity. Therefore, the oil injection pulse width calculation is simple, accurate, convenient, fast and highly real-time.

Description

Technical Field

[0001] This application relates to the field of engine fuel injection control technology, and in particular to a method, device and storage medium for calculating fuel injection pulse width. Background Technology

[0002] In electronically controlled common rail diesel engines, the electronically controlled fuel injectors typically use solenoid valves as the actuators of the fuel injection system. The operation of the solenoid valve is controlled by the drive current: when the drive current is zero, the corresponding electromagnetic force is also zero, and the solenoid valve remains closed; when the drive current is large, the generated electromagnetic force is also large, the solenoid valve opens, and the injector begins to inject fuel into the cylinder until the drive current returns to zero, at which point the solenoid valve closes, and fuel injection ends. The start and end of the drive current's rise are determined by the control signal from the electronic control unit (ECU). When the control signal is on, the drive current value rises from zero; when the control signal is off, the drive current falls from its peak. The injection pulse width refers to the duration of the control signal sent by the ECU to the solenoid valve; therefore, the injection pulse width is positively correlated with the injection quantity. Measuring the injection pulse width during diesel engine operation is crucial for accurately measuring the injection quantity, optimizing combustion efficiency, reducing pollutant emissions, and lowering noise. Summary of the Invention

[0003] One objective of this application is to provide a method, device, and storage medium for calculating fuel injection pulse width, in order to solve the problems of cumbersome algorithms, long processing time, poor real-time performance, and insufficient calculation accuracy in existing technologies.

[0004] According to one aspect of this application, a method for calculating the injection pulse width is provided. The method includes: acquiring a solenoid valve current signal, and taking the moment when the sampled value of the solenoid valve current signal exceeds a preset threshold as the start time of an injection control signal; using the start time of the injection control signal as a reference, acquiring an effective waveform segment of the solenoid valve current signal, and determining the data length of the effective waveform segment; determining a calibration value under a set calibration condition, and determining a pulse width type based on the data length of the effective waveform segment and the calibration value, wherein the calibration value includes a first calibration value and a second calibration value; determining the end time of the injection control signal based on the pulse width type, and determining the injection pulse width based on the start time, end time, and preset correction amount of the injection control signal.

[0005] Optionally, determining the end time of the fuel injection control signal based on the pulse width type includes: determining the starting point for differentiation corresponding to the effective waveform segment based on the pulse width type; starting from the starting point for differentiation, differentiating the effective waveform segment, and determining the time corresponding to the minimum value of the derivative as the end time of the fuel injection control signal.

[0006] Optionally, determining the derivative start point corresponding to the effective waveform segment based on the pulse width type includes: if the pulse width type is a first type of pulse width, then determining the derivative start point based on the start time of the fuel injection control signal, wherein the data length of the effective waveform segment corresponding to the first type of pulse width is less than a first calibration value, and the first calibration value is determined by the calibration condition.

[0007] Optionally, determining the derivative start point corresponding to the effective waveform segment based on the pulse width type includes: if the pulse width type is a second type of pulse width, then determining the derivative start point based on a second calibration value, wherein the data length of the effective waveform segment corresponding to the second type of pulse width is greater than or equal to a first calibration value, and the second calibration value is determined by the calibration conditions.

[0008] Optionally, the method further includes: acquiring the waveform of the solenoid valve current signal under the maximum injection pulse width condition; and setting the calibration condition based on the waveform of the solenoid valve current signal.

[0009] Optionally, the step of setting the calibration condition based on the solenoid valve current signal waveform includes: taking the derivative of the solenoid valve current signal waveform to determine the first moment corresponding to the minimum value of the derivative; determining the second moment when the derivative is greater than or equal to zero for the first time after the first moment; and obtaining the corresponding condition where the injection pulse width is equal to the difference between the second moment and the start time of the injection control signal, and setting it as the calibration condition.

[0010] Optionally, determining the calibration value under the set calibration conditions includes: under the set calibration conditions, acquiring the portion of the solenoid valve current signal waveform whose signal value exceeds the preset threshold, and calibrating the time length of this portion as the first calibration value.

[0011] Optionally, determining the calibration value under the set calibration conditions includes: under the set calibration conditions, differentiating the waveform of the solenoid valve current signal, determining the time corresponding to the maximum value of the derivative between the first time and the second time, and calibrating the time corresponding to the maximum value of the derivative as the second calibration value.

[0012] According to another aspect of this application, an electronic device is also provided, comprising: one or more processors; and a memory storing computer-readable instructions that, when executed, cause the processor to perform operations as described above.

[0013] According to another aspect of this application, a computer-readable medium is also provided, having stored thereon computer-readable instructions that can be executed by a processor to implement the method as described above.

[0014] Compared with existing technologies, this application acquires the solenoid valve current signal and uses the moment when the sampled value of the solenoid valve current signal exceeds a preset threshold as the start time of the fuel injection control signal. Based on the start time of the fuel injection control signal, it obtains the effective waveform segment of the solenoid valve current signal and determines the data length of the effective waveform segment. Under set calibration conditions, it determines the calibration amount, and determines the pulse width type based on the data length of the effective waveform segment and the calibration amount, wherein the calibration amount includes a first calibration amount and a second calibration amount. Based on the pulse width type, it determines the end time of the fuel injection control signal, and determines the fuel injection pulse width based on the start time, end time, and preset correction amount of the fuel injection control signal. This achieves simple, accurate, and high real-time performance in fuel injection pulse width calculation, enabling quick and convenient matching to different application scenarios. Attached Figure Description

[0015] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 A flowchart illustrating a method for calculating fuel injection pulse width according to one aspect of this application is shown. Figure 2 The diagram shows the waveforms of the solenoid valve current signals corresponding to different injection pulse widths in one embodiment of this application. Figure 3 The waveform of the solenoid valve current signal corresponding to another interval injection pulse width is shown in one embodiment of this application. Figure 4 The diagram shows the waveform after differentiating the original current waveform in one embodiment of this application. Figure 5 The diagram shows a waveform obtained by differentiating another original current waveform in one embodiment of this application. Figure 6 The diagram shows the waveform of the solenoid valve current signal collected under the maximum injection pulse width condition in one embodiment of this application, as well as schematic diagrams of the first and second moments. Figure 7 A schematic diagram of the first calibration quantity L and the second calibration quantity S in one embodiment of this application is shown; Figure 8 This diagram illustrates a flowchart of fuel injection pulse width calculation in one embodiment of this application. Figure 9 A flowchart illustrating the specific calculation process of the injection pulse width in one embodiment of this application is shown. Figure 10 A schematic diagram of a frame of an electronic device provided according to another aspect of this application is shown.

[0016] The same or similar reference numerals in the accompanying drawings represent the same or similar parts. Detailed Implementation

[0017] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0018] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein, and therefore this application is not limited to the specific embodiments disclosed below.

[0019] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not specifically singular and may include plural forms. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0020] The existing technical solutions for calculating the injection pulse width of electronic fuel injectors typically include the following: (1) The internally output injection pulse width data can be directly retrieved through the engine electronic management system.

[0021] (2) The feature extraction of the rail pressure signal waveform is used to obtain the injection pulse width.

[0022] (3) The driving current is converted into fiber current by fiber current converter, and the time interval between the two falling edges of fiber current is measured by timer to obtain the injection pulse width.

[0023] (4) Calculate the injection pulse width using formulas based on the engine's operating parameters (such as speed, injection quantity and leakage).

[0024] (5) Using a current clamp, the solenoid valve current signal is obtained through mutual inductance effect. The inflection point of the waveform is obtained by taking the derivative of the solenoid valve current signal waveform twice, and the injection pulse width is obtained through calculation.

[0025] However, each of these methods has its shortcomings and limitations. First, while obtaining the injection pulse width from the electronic control unit (ECU) is simple and direct, it suffers from high latency, insufficient real-time performance, and potential discrepancies between ECU data and actual values. Second, indirectly calculating the injection pulse width by extracting features from the rail pressure signal can be inaccurate and is easily affected by the opening and closing delays of the solenoid valve. Third, while measuring the falling edge interval of the fiber optic current to obtain the injection pulse width is accurate and provides better information on the opening and closing delays of the solenoid valve, its application is limited. In some scenarios, fiber optic current sensors cannot be installed on diesel engines, requiring the original solenoid valve current signal waveform as input. Fourth, this indirect calculation method suffers from insufficient accuracy and complex algorithms. Fifth, directly calculating the solenoid valve current signal offers good accuracy and real-time performance, but it requires utilizing the monotonicity of the solenoid valve current signal waveform to find all inflection points and then analyzing them, resulting in a complex algorithm and long computation time.

[0026] To address the aforementioned issues, the injection pulse width calculation method proposed in this application is based on the solenoid valve current signal obtained through mutual inductance effect. It is simple, accurate, and has high real-time performance, making it suitable for a wide range of applications.

[0027] Figure 1 The diagram shows a flowchart of a method for calculating the injection pulse width according to one aspect of this application, the method comprising steps S11 to S14.

[0028] Step S11: Acquire the solenoid valve current signal, and take the moment when the sampled value of the solenoid valve current signal exceeds a preset threshold as the start time of the fuel injection control signal.

[0029] The solenoid valve current signal is acquired in real time by a current acquisition device. In one working cycle, when the amplitude of the acquired solenoid valve current signal exceeds the set threshold for the first time, that moment is regarded as the start moment of the control signal.

[0030] For example, a current clamp is used to acquire the solenoid valve current signal based on the mutual inductance effect, and the current signal is converted into a voltage signal and input to an analog-to-digital converter (ADC). A threshold T is preset for the ADC, and sampling is continuously performed during the operation of the solenoid valve. When the sampled voltage value first exceeds the threshold T, it is determined that the fuel injection control signal output by the electronic control unit is validly opened, and the solenoid valve begins to operate. This moment is recorded as the start time of the fuel injection control signal.

[0031] Step S12: Based on the start time of the fuel injection control signal, obtain the effective waveform segment of the solenoid valve current signal and determine the data length of the effective waveform segment.

[0032] Using the start time of the fuel injection control signal determined in step S11 as the starting point, a complete segment of the solenoid valve current signal after that time is captured and saved to form an effective waveform segment. The duration of this effective waveform segment should not be less than the maximum fuel injection pulse width of the diesel engine to ensure complete coverage of the current changes related to the entire fuel injection process, and the data length corresponding to this effective waveform segment is further determined.

[0033] For example, using a threshold T as a reference, the intervals in the effective waveform segments where the current signal is greater than the threshold T are identified, and the data length l corresponding to the interval is calculated. This data length l is numerically equivalent to the data length corresponding to the sum of the fuel injection pulse width and the solenoid valve closing delay.

[0034] Step S13: Determine the calibration quantity under the set calibration conditions, and determine the pulse width type according to the data length of the effective waveform segment and the calibration quantity, wherein the calibration quantity includes a first calibration quantity and a second calibration quantity.

[0035] The length of the acquired valid waveform segment data is compared with the calibrated value to classify the corresponding pulse width types. This allows for the matching of appropriate injection pulse width calculation methods for different pulse width types in subsequent steps. Different pulse width types exhibit differences in solenoid valve action characteristics and current waveform attenuation patterns; therefore, corresponding calculation methods are needed to determine the end time of the injection control signal, thereby further calculating the injection pulse width.

[0036] Step S14: Determine the end time of the fuel injection control signal according to the pulse width type, and determine the fuel injection pulse width based on the start time, end time and preset correction amount of the fuel injection control signal.

[0037] Different pulse width types require corresponding calculation methods to determine the end time of the fuel injection control signal. The fuel injection pulse width is calculated by superimposing a correction amount on a reference duration. The reference duration is the difference between the end time and the start time of the fuel injection control signal. The preset correction amount is a system constant used to compensate for minor interferences such as sampling accuracy errors, solenoid valve current response delays, and signal transmission delays. Under the premise of the same cylinder and a fixed threshold T, the correction amount remains unchanged and only needs to be measured once during the initial debugging and calibration phase of the system.

[0038] In practical applications, the specific formula for calculating the fuel injection pulse width is as follows: Injection pulse width = Control signal end time - Control signal start time + Correction amount C The correction amount C can be calibrated during the system debugging phase through standard operating condition comparison tests. When the threshold T remains unchanged for the same cylinder, the correction amount C can be regarded as a constant and does not need to be adjusted in real time. The final calculated result is the precise injection pulse width corresponding to the current diesel engine working cycle.

[0039] In one embodiment of this application, in step S14, the starting point for differentiation corresponding to the effective waveform segment is determined according to the pulse width type; starting from the starting point for differentiation, the effective waveform segment is differentiated, and the time corresponding to the minimum value of the derivative is determined as the end time of the fuel injection control signal.

[0040] The waveform variation of the solenoid valve current signal differs depending on the injection pulse width type. If a uniform starting point for differentiation is used for all valid waveform segments, the minimum derivative value will not match the actual end time of the injection control signal, leading to distorted end-time determination. Therefore, it is necessary to select a differentiated starting point for differentiation based on the defined pulse width type before performing subsequent differentiation calculations to ensure the accuracy of end-time determination.

[0041] Figure 2 and Figure 3 The following diagrams show the solenoid valve current signal waveforms corresponding to different injection pulse widths in one embodiment. The orange solid line indicates the end time of the actual injection control signal.

[0042] Figure 4 and Figure 5 They are respectively Figure 2 and Figure 3 The waveform obtained after differentiating the original current waveform, where, Figure 4 right Figure 2 After differentiating the current signal waveform, the minimum value of the derivative waveform accurately corresponds to the end time of the actual control signal, and the judgment result is correct. Figure 5 right Figure 3 After differentiating the current signal waveform, the determination results for the short pulse width interval (250us, 300us, 350us, 500us) are accurate, while the minimum value of the derivative for the long pulse width interval (900us, 2000us) is not the end time of the actual control signal, and the determination fails.

[0043] Therefore, it is necessary to first match the corresponding derivative start point according to the pulse width type, limit the starting position of the derivative operation, and then perform differential derivative processing on the effective waveform segment of the solenoid valve current starting point, extract the minimum point in the waveform after derivative, and finally determine the time corresponding to the point as the end time of the fuel injection control signal.

[0044] Furthermore, if the pulse width type is a first type of pulse width, the starting point for differentiation is determined according to the start time of the fuel injection control signal, wherein the data length of the effective waveform segment corresponding to the first type of pulse width is less than the first calibration value, and the first calibration value is determined by the calibration condition.

[0045] The pulse width type can be classified according to the first calibration value, which is determined under calibration conditions. When the data length l of the effective waveform segment is less than the first calibration value (e.g., L), the current pulse width can be determined to be a type I pulse width. Under small pulse width conditions, the solenoid valve current waveform has a typical single change pattern: at the instant the fuel injection control signal is closed, the solenoid valve is de-energized, and the voltage value corresponding to the current signal drops rapidly. At this time, the voltage drop rate reaches the peak value of the entire waveform, and the drop speed is the fastest. Subsequently, as the voltage continues to decrease, the drop rate gradually slows down. Based on this characteristic, the waveform derivative corresponding to the fastest drop in inflection point is negative, and it is also the minimum derivative value of the entire current waveform.

[0046] Therefore, without adjusting the starting point of differentiation, the starting time of the fuel injection control signal can be directly used as the starting point of differentiation. By differentiating over the complete and effective waveform segment, the ending time of the corresponding fuel injection control signal closing can be accurately captured.

[0047] Furthermore, if the pulse width type is a second type of pulse width, the starting point for differentiation is determined according to the second calibration value, wherein the data length of the effective waveform segment corresponding to the second type of pulse width is greater than or equal to the first calibration value, and the second calibration value is determined by the calibration condition.

[0048] The second type of pulse width can be classified based on the first calibrated value (such as L). When the data length of the effective waveform segment l ≥ L, the current pulse width is determined to be a second type of pulse width. Under the condition of large pulse width, the effective waveform segment of the solenoid valve current is longer and there are more waveform change stages. If the full derivative method of the first type of pulse width is used, the current fluctuation in the first part of the waveform will interfere with the determination of the minimum value of the derivative, causing the minimum value to deviate from the actual signal closing position, resulting in a judgment error.

[0049] Therefore, based on the second calibration, the starting point for differentiation corresponding to the second type of pulse width can be located, discarding the invalid fluctuation interval in the first part of the waveform, and only performing differentiation calculations from this starting point onwards. Within this interval, when the fuel injection control signal is closed, the solenoid valve current and voltage will drop sharply, and the rate of drop will reach the peak value of this waveform segment. The derivative at the corresponding point is negative and is the minimum value in this differentiated waveform segment, which can accurately match the end time of the fuel injection control signal.

[0050] In practical applications, under the calibration conditions of the diesel engine, the first calibration value L and the second calibration value S are calibrated. The second calibration value S is the positioning parameter for the starting point of differentiation under large pulse width conditions, and the calibration value satisfies S≤L to ensure that the starting point of differentiation falls within a reasonable waveform range and avoids interference from invalid waveforms in the early stage. The measured effective waveform segment data length l is compared with the first calibration value L. When l≥L, the current pulse width is determined to be a second type of large pulse width.

[0051] After confirming the pulse width type as Type II, the starting point for differentiation is no longer the initial moment of the injection control signal. Instead, based on the second calibration value S, the position corresponding to the subscript S of the effective waveform segment of the solenoid valve current is located, and this position is set as the starting point for this differentiation calculation. Differentiation is then performed segment by segment on the remaining waveform starting from this point. Under the large pulse width condition, the solenoid valve current decreases the fastest when the control signal is closed. The derivative value corresponding to this inflection point is the minimum negative value within the entire differentiation interval starting from point S. Extracting the moment corresponding to this minimum value allows for precise determination of the end moment of the injection control signal.

[0052] In one embodiment of this application, under the condition of maximum injection pulse width, the waveform of the solenoid valve current signal is acquired; and the calibration condition is set according to the waveform of the solenoid valve current signal.

[0053] Under the maximum injection pulse width condition, the injection duration is the longest and the solenoid valve current waveform is the most complete. The diesel engine with the electronically controlled injector under test is adjusted to the maximum injection pulse width condition C. max This operating condition represents the longest injection duration within the rated operating range of the injector, ensuring that the solenoid valve operates throughout its entire range and that the current waveform remains uninterrupted.

[0054] For example, a current clamp can be used in conjunction with an analog-to-digital converter to acquire the complete current signal of the solenoid valve under this operating condition in real time, convert it into a voltage waveform, and store it to obtain a reference current waveform. Subsequently, a preliminary derivative analysis is performed on the reference waveform to check the matching degree between the minimum value of the derivative and the actual fuel injection end time. Based on the waveform characteristics, the dedicated calibration conditions for subsequent calibration are determined, and the waveform acquisition before calibration is completed.

[0055] Furthermore, the waveform of the solenoid valve current signal is differentiated to determine the first moment corresponding to the minimum value of the derivative; the second moment when the derivative is greater than or equal to zero for the first time after the first moment is determined; the corresponding working condition in which the injection pulse width is equal to the difference between the second moment and the start moment of the injection control signal is obtained and set as the calibration working condition.

[0056] The derivative of the solenoid valve current signal waveform acquired under the maximum injection pulse width condition is calculated. The first moment is the moment corresponding to the minimum value of the derivative of the current waveform under the maximum injection pulse width condition, which is the inflection point where the waveform decline rate is the fastest; the second moment is the moment after the first moment when the derivative first returns to a non-negative value, indicating the end of the current decline phase and the waveform entering the stable phase.

[0057] In practical applications, if, after eliminating errors, the time corresponding to the minimum value of the derivative waveform minus the opening time is exactly equal to the injection pulse width, it indicates that the time corresponding to the minimum point of the derivative of the solenoid valve current signal waveform under various operating conditions of the electronic fuel injector is the end time of the injection pulse width. Therefore, both S and L are calibrated to 0, and the calibration work is completed. If, after eliminating errors, the time corresponding to the minimum value of the derivative waveform minus the opening time is much smaller than the maximum injection pulse width, it indicates that the time corresponding to the minimum point of the derivative of the solenoid valve current signal waveform under various operating conditions of the electronic fuel injector is not necessarily the end time of the injection pulse width.

[0058] Next, the time difference between the second moment and the start moment of the fuel injection control signal is calculated, and this difference is used as the target fuel injection pulse width. The working condition corresponding to the pulse width is set as the calibration working condition. This working condition can distinguish between large and small pulse widths and calibrate two calibration values ​​(first calibration value and second calibration value).

[0059] exist Figure 6 In the illustrated embodiment, the blue curve represents the solenoid valve current signal waveform acquired under the maximum injection pulse width condition; t1 is the time corresponding to the lowest point of the derivative, i.e., the first moment; t2 is the time corresponding to the first time the derivative is not less than zero after the lowest point, i.e., the second moment; the purple dashed line represents the injection end time. The time difference between t2 and the start time of the injection control signal is calculated, and this difference is the target calibration injection pulse width. Subsequently, this target injection pulse width is matched to find the corresponding stable operating condition, which is then set as the dedicated calibration condition C for subsequent calibration of the L and S pulse widths. s .

[0060] In one embodiment of this application, in step S13, under the set calibration conditions, the portion of the solenoid valve current signal waveform whose signal value exceeds the preset threshold is obtained, and the time length of this portion is calibrated as the first calibration value.

[0061] The solenoid valve current waveform under calibration conditions is collected. Using the threshold method, the continuous interval in the waveform where the signal value is greater than or equal to the threshold T is selected. This interval completely covers the effective stage and the closing delay stage of the fuel injection control signal. The corresponding time length is the classification threshold value of the pulse width. This length is directly calibrated as the first calibration value L.

[0062] exist Figure 7 In the illustrated embodiment, the blue curve represents calibration condition C. s The current waveform of the solenoid valve was collected below. Figure 7 The calibration value L in the above figure is the first calibration value determined by the threshold method, which is used to distinguish between the first type of pulse width and the second type of pulse width.

[0063] Furthermore, under the set calibration conditions, the waveform of the solenoid valve current signal is differentiated, and the time corresponding to the maximum value of the derivative is determined between the first time and the second time. The time corresponding to the maximum value of the derivative is then calibrated as the second calibration value.

[0064] Under the same calibration conditions, the current waveform is differentiated again. Within the waveform interval between the first time t1 and the second time t2, the maximum value of the derivative within this interval is found, and the time corresponding to the maximum value is calibrated as the second calibration value S.

[0065] Continue to refer to Figure 7 Within the waveform interval between the first time t1 and the second time t2, find the time corresponding to the maximum value of the derivative. The value of this time is calibrated as the second calibration value S, which serves as the starting point for differentiation in the second type of pulse width. That is, for large pulse width type waveforms, differentiation is directly started from this time S.

[0066] exist Figure 8 The illustrated embodiment demonstrates a flowchart of the fuel injection pulse width calculation process. First, the start time of the control signal is determined by periodically acquiring the solenoid valve current signal, and a specific length of the solenoid valve current signal waveform is acquired and processed. After the solenoid valve current signal waveform acquisition is complete, the fuel injection pulse width calculation process is triggered. The solenoid valve current signal waveform is processed to obtain the end time of the control signal. Finally, this end time is subtracted from the start time of the solenoid valve current signal waveform acquisition, and a correction amount is added to obtain the fuel injection pulse width.

[0067] exist Figure 9 The illustrated embodiment demonstrates a flowchart of the specific calculation process for the fuel injection pulse width. When the voltage value of the solenoid valve current signal exceeds a threshold T, the solenoid valve current signal acquisition is triggered, and after acquisition, the fuel injection pulse width calculation is triggered. Using the threshold T again, the sum of the fuel injection pulse width and the shutdown delay, l, is obtained through the threshold method, where l is the data length of the effective waveform segment. l is compared with the first calibration value L. If l ≥ L, the derivative waveform of the solenoid valve current signal starting from the second calibration value S is differentiated to obtain the derivative waveform; if l < L, the derivative waveform of the solenoid valve current signal starting from the start time is differentiated to obtain the derivative waveform. The lowest point of the derivative waveform is found, and the sampling time of the solenoid valve current signal waveform corresponding to this point is recorded as the end time. This end time is subtracted from the start time of the solenoid valve signal waveform acquisition, and then a correction amount C is added to obtain the fuel injection pulse width.

[0068] This application proposes a fast, space-saving, highly accurate, and easy-to-deploy technical solution for calculating fuel injection pulse width. It obtains the solenoid valve current signal waveform (i.e., the drive current signal waveform) through mutual inductance, differentiates the waveform, and combines the minimum derivative value with a constant correction term to obtain the fuel injection pulse width. Deployment requires only two calibration units, and the solution ensures good accuracy and real-time performance in fuel injection pulse width calculation while occupying minimal storage space. Furthermore, it requires less computing power and has low hardware requirements, making it economical.

[0069] In one embodiment of this application, two types of electronic fuel injectors were tested. The sampling period of the solenoid valve current signal was 10µs; the analog-to-digital converter value ranged from 0 to 4095, corresponding to a voltage of 0 to 3.3V.

[0070] The lowest point of the derivative of the solenoid valve current signal under various operating conditions of the first type of injector is the time when the injection ends. Therefore, L and S are calibrated to 0, the threshold T is set to 10, and the correction C is set to -10us. The final actual pulse width length, the calculation results using this technical solution, and the error are shown in Table 1. It can be seen that the absolute value of the error does not exceed 20us, and the average error is 8.6364us.

[0071]

[0072] Table 1

[0073] For the second type of injector, under conditions of large injection pulse width, the lowest point of the derivative of the solenoid valve current signal does not coincide with the injection end time. After calibration, L and S were set to 580µs and 310µs respectively, the threshold T was set to 10, and the correction C was set to +10µs. The calculation results and errors are shown in Table 2. It can be seen that the absolute value of the error does not exceed 10µs, and the average error is 3.5µs.

[0074]

[0075] Table 2

[0076] In engineering practice, the difficulty in calculating the injection pulse width from the solenoid valve current signal waveform lies in eliminating the influence of the time difference (i.e., the injector shut-off delay) between the end of the injection pulse width and the moment the solenoid valve current signal drops to zero. Different injection pulse widths correspond to different waveform shapes of the solenoid valve current signal. When the injection pulse width exceeds a certain value, the solenoid valve current signal waveform exhibits a voltage-stable portion, known as chopping. Conversely, when the injection pulse width is less than a certain level, the solenoid valve current signal waveform does not exhibit chopping. The shut-off delay with and without chopping waveforms differs, and the shut-off delay without chopping waveforms varies with the voltage value of the solenoid valve current signal at the end of the injection pulse width. In summary, without chopping, the shut-off delay exhibits high uncertainty. Therefore, without chopping of the solenoid valve current signal, it is difficult to directly deduce the shut-off delay and injection pulse width using the threshold method. Therefore, the algorithm used to calculate the injection pulse width through the solenoid valve current signal must be able to eliminate the influence of the injector shut-off delay on the calculation results under all operating conditions. The difficulty lies in eliminating the influence of the injector shut-off delay on the calculation results under operating conditions where the injection pulse width is small and the solenoid valve current signal waveform is not chopped.

[0077] The technical solution proposed in this application can calculate a relatively accurate pulse width based solely on the solenoid valve current signal waveform, without the involvement of the rail pressure waveform or the need to convert the solenoid valve current signal into an optical fiber current signal. By differentiating the waveform, the end time of the control signal can be found, without being affected by the injector closing delay, thus satisfying accurate measurement under all operating conditions. By using a threshold method to initially determine whether the injection pulse width corresponding to the injection pulse width curve is a large or small pulse width, and by using a piecewise discussion method to avoid the problem that the minimum point of the waveform derivative is not necessarily the end time of the control signal, the algorithm is suitable for various solenoid valve current signal waveforms and has a wide range of applications. It only requires one differentiation of the waveform, with short computation time and a simple algorithm.

[0078] Compared with existing technologies, the technical solution proposed in this application does not indirectly calculate the injection pulse width through oil pressure, but directly calculates it through the waveform of the solenoid valve current signal, resulting in higher accuracy. The algorithm is simple and fast, ensuring the real-time performance of the pulse width calculation. The injection pulse width algorithm itself only requires setting two calibration values, and the overall technical solution requires very few calibration values, so it can be quickly and easily matched and calibrated according to different application scenarios. Compared with fiber optic current sensors, the mutual inductance sensor used in this solution is cheaper, has a lower failure rate, and can be applied to a wider range of scenarios.

[0079] Figure 10 A schematic diagram of the framework of an electronic device according to another aspect of this application is shown, the electronic device including at least a processor 1001 and a memory 1002.

[0080] Processor 1001 may include one or more processing cores, such as a quad-core processor, an octa-core processor, etc. Processor 1001 may be implemented using at least one hardware form selected from DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), and PLA (Programmable Logic Array). Processor 1001 may also include a main processor and a coprocessor. The main processor, also known as a CPU (Central Processing Unit), is used to process data in the wake-up state; the coprocessor is a low-power processor used to process data in the standby state. In some embodiments, processor 1001 may integrate a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content to be displayed on the screen. In some embodiments, processor 1001 may also include an AI (Artificial Intelligence) processor, which is used to handle computational operations related to machine learning.

[0081] The memory 1002 may include one or more computer-readable storage media, which may be non-transitory. The memory 1002 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices or flash memory devices. In some embodiments, the non-transitory computer-readable storage media in the memory 1002 is used to store at least one instruction, which is executed by the processor 1001 to implement a fuel injection pulse width calculation method provided in the method embodiments of this application.

[0082] In some embodiments, the electronic device may also optionally include: a peripheral device interface and at least one peripheral device. The processor 1001, memory 1002, and peripheral device interface can be connected via a bus or signal line. Each peripheral device can be connected to the peripheral device interface via a bus, signal line, or circuit board. Indicatively, peripheral devices include, but are not limited to: radio frequency circuits, touch displays, audio circuits, and power supplies.

[0083] Of course, the electronic device may also include fewer or more components, and this embodiment does not limit this.

[0084] This application also provides a computer-readable medium having computer instructions stored thereon, which can be executed by a processor to implement a fuel injection pulse width calculation method as described above.

[0085] When the fuel injection pulse width calculation method is implemented as a computer program, it can also be stored as an article of manufacture in a computer-readable storage medium. For example, computer-readable storage media can include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, magnetic stripes), optical discs (e.g., compact discs (CDs), digital multifunction discs (DVDs)), smart cards, and flash memory devices (e.g., electrically erasable programmable read-only memory (EPROM), cards, sticks, key drives). Furthermore, the various storage media described herein can represent one or more devices and / or other machine-readable media used for storing information. The term "machine-readable medium" can include, but is not limited to, wireless channels and various other media (and / or storage media) capable of storing, containing, and / or carrying code and / or instructions and / or data.

[0086] It should be understood that the embodiments described above are merely illustrative. The embodiments described herein may be implemented in hardware, software, firmware, middleware, microcode, or any combination thereof. For hardware implementation, the processor may be implemented within one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, and / or other electronic units designed to perform the functions described herein, or combinations thereof.

[0087] Some aspects of this application can be executed entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The aforementioned hardware or software may be referred to as a "data block," "module," "engine," "unit," "component," or "system." The processor may be one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DAPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, or combinations thereof. Furthermore, aspects of this application may manifest as computer products residing in one or more computer-readable media, including computer-readable program code. For example, computer-readable media may include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, magnetic tapes, etc.), optical discs (e.g., compressed CDs, digital multifunction DVDs, etc.), smart cards, and flash memory devices (e.g., cards, sticks, key drives, etc.).

[0088] A computer-readable medium may contain a propagated data signal containing computer program code, for example, on baseband or as part of a carrier wave. This propagated signal may take various forms, including electromagnetic, optical, and so on, or suitable combinations thereof. A computer-readable medium can be any computer-readable medium other than a computer-readable storage medium, which can be connected to an instruction execution system, apparatus, or device to enable communication, propagation, or transmission of a program for use. The program code located on the computer-readable medium can be propagated through any suitable medium, including radio, cable, fiber optic cable, radio frequency signals, or similar media, or any combination of the above media.

[0089] The basic concepts have been described above. Obviously, for those skilled in the art, the above disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0090] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0091] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of scope in some embodiments of this application are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

Claims

1. A method for calculating fuel injection pulse width, characterized in that, The method includes: Collect the solenoid valve current signal, and take the moment when the sampled value of the solenoid valve current signal exceeds a preset threshold as the start time of the fuel injection control signal; Based on the start time of the fuel injection control signal, the effective waveform segment of the solenoid valve current signal is obtained, and the data length of the effective waveform segment is determined. Under the set calibration conditions, the calibration quantity is determined, and the pulse width type is determined according to the data length of the effective waveform segment and the calibration quantity, wherein the calibration quantity includes a first calibration quantity and a second calibration quantity; The end time of the fuel injection control signal is determined according to the pulse width type, and the fuel injection pulse width is determined based on the start time, end time and preset correction amount of the fuel injection control signal.

2. The method according to claim 1, characterized in that, Determining the end time of the fuel injection control signal based on the pulse width type includes: Based on the pulse width type, determine the starting point for differentiation corresponding to the effective waveform segment; Starting from the point where the derivative is calculated, the derivative of the effective waveform segment is calculated, and the time corresponding to the minimum value of the derivative is determined as the end time of the fuel injection control signal.

3. The method according to claim 2, characterized in that, The step of determining the starting point for differentiation corresponding to the effective waveform segment based on the pulse width type includes: If the pulse width type is the first type of pulse width, the starting point of the derivative is determined according to the start time of the fuel injection control signal, wherein the data length of the effective waveform segment corresponding to the first type of pulse width is less than the first calibration value, and the first calibration value is determined by the calibration condition.

4. The method according to claim 2, characterized in that, The step of determining the starting point for differentiation corresponding to the effective waveform segment based on the pulse width type includes: If the pulse width type is the second type of pulse width, the starting point for differentiation is determined according to the second calibration value, wherein the data length of the effective waveform segment corresponding to the second type of pulse width is greater than or equal to the first calibration value, and the second calibration value is determined by the calibration condition.

5. The method according to claim 1, characterized in that, The method further includes: Under the condition of maximum fuel injection pulse width, the waveform of the solenoid valve current signal is collected; The calibration conditions are set according to the waveform of the solenoid valve current signal.

6. The method according to claim 5, characterized in that, The step of setting the calibration conditions based on the waveform of the solenoid valve current signal includes: The derivative of the solenoid valve current signal waveform is calculated to determine the first moment corresponding to the minimum value of the derivative; Determine the second moment after the first moment when the derivative is first greater than or equal to zero; Obtain the corresponding operating condition where the injection pulse width is equal to the difference between the second time and the start time of the injection control signal, and set it as the calibration operating condition.

7. The method according to claim 6, characterized in that, Determining the calibration quantity under the set calibration conditions includes: Under the set calibration conditions, the portion of the solenoid valve current signal waveform whose signal value exceeds the preset threshold is obtained, and the time length of this portion is calibrated as the first calibration value.

8. The method according to claim 6, characterized in that, Determining the calibration quantity under the set calibration conditions includes: Under the set calibration conditions, the waveform of the solenoid valve current signal is differentiated, and the time corresponding to the maximum value of the derivative is determined between the first time and the second time. The time corresponding to the maximum value of the derivative is then calibrated as the second calibration value.

9. An electronic device, characterized in that, The electronic device includes: One or more processors; And a memory storing computer-readable instructions, which, when executed, cause the processor to perform the operations of the method as described in any one of claims 1 to 8.

10. A computer-readable medium having stored thereon computer instructions that can be executed by a processor to implement the method as described in any one of claims 1 to 8.

Images