Engine working cycle detection method and device and engine

Abstract

This application discloses an engine working cycle detection method, device, and engine. It collects oil pressure signals from the cylinder that first performs power in an engine working cycle, simplifying the process and facilitating accurate subsequent positioning of the power and intake / exhaust valve positions of each cylinder within a working cycle. Furthermore, it performs scaling processing on the collected oil pressure signals, optimizing the original signals without altering peak values. This reduces invalid signals and amplifies valid signals. A sliding window algorithm further optimizes the positioning of each engine working cycle, accurately pinpointing the intake / exhaust valve positions and impact locations of each cylinder during power delivery, providing strong support for subsequent engine fault diagnosis.

Description

Technical Field

[0001] This application relates to, but is not limited to, complex mechanical fault diagnosis technology, and particularly to an engine working cycle detection method and device and an engine. Background Technology

[0002] An engine, such as a diesel engine, is a reciprocating mechanical device. The working principle of an engine is to convert heat energy into kinetic energy. Taking a four-stroke engine as an example, each working cycle includes four strokes: intake, compression, power, and exhaust. The flywheel rotates twice after each working cycle. Typically, during engine operation, elastic structural components inside the engine, such as pistons, connecting rods, crankshafts, and the engine block, are excited by various forms of elastic vibration under the force of combustion gases and inertia. These vibrations mainly include the following excitation forces: combustion impact, exhaust valve opening impact, intake valve opening impact, exhaust valve seating impact, and intake valve seating impact. If the engine experiences misfire or abnormal valve clearance, the vibration response of the cylinder head surface will change. Based on these phenomena, related technologies typically install vibration sensors on the engine cylinder head to collect vibration data and analyze the collected data for typical engine fault diagnosis.

[0003] To accurately pinpoint the impact locations of the intake and exhaust valves and the power stroke in each cylinder based on vibration data, it's typically necessary to accurately capture each engine working cycle. Common methods for capturing each engine working cycle generally involve: installing a flywheel tooth pulse sensor near the flywheel ring gear to acquire the rotational speed signal of each tooth; and creating a broken tooth on the flywheel ring gear so that the pulse sensor cannot generate a pulse signal when passing through the broken tooth. Thus, the time from the current missing signal to the next missing signal is half a working cycle. However, this method has significant limitations. Firstly, the pulse sensor requires a suitable installation location; secondly, the broken tooth on the flywheel ring gear is essential, and both are indispensable. Furthermore, after acquiring the pulse signal, it's necessary to further determine whether the period between two missing signals represents the first or second half of an engine working cycle, which can easily lead to misjudgment. Summary of the Invention

[0004] This application provides an engine working cycle detection method, device, and engine, which can accurately locate the position of the intake and exhaust valves of each cylinder and the impact position generated by the power stroke, providing a strong guarantee for subsequent engine fault diagnosis.

[0005] This invention provides a method for detecting engine duty cycles, comprising:

[0006] The engine's oil pressure and vibration signals are collected, with the oil pressure signal being collected by an oil pressure sensor installed on the cylinder that performs the first work cycle in the engine.

[0007] The acquired oil pressure signals are scaled to reduce invalid signals and amplify valid signals;

[0008] Based on the scaled oil pressure signal, the location of the injection peak is extracted using a sliding window algorithm;

[0009] The location of the extracted fuel injection peak is mapped onto the collected vibration signal to pinpoint the power stroke of each cylinder and the impact of intake and exhaust valve opening and closing within a working cycle.

[0010] In one exemplary instance, before mapping the location of the extracted fuel injection peak onto the acquired vibration signal, the method further includes:

[0011] Outlier removal is performed on the location of the extracted fuel injection peak.

[0012] In one exemplary instance, the outlier removal process for the location of the extracted fuel injection peak includes:

[0013] Obtain the maximum speed N of the engine max The minimum speed N during normal driving min ;

[0014] Combined with the sampling rate fs, the maximum rotational speed N max and minimum speed N min Calculate the number of sampling points T corresponding to the maximum time length in a work cycle. max The number of sampling points T corresponding to the minimum time length min ,in,

[0015] The number of sampling points T corresponding to the calculated maximum time length max The number of sampling points T corresponding to the minimum time length min For a work cycle, the number T of sampling points whose difference between the end and start positions is greater than the maximum time length is eliminated. max Or the difference between its end position and start position is less than the number of sampling points T corresponding to the minimum time length. min Location information.

[0016] In one exemplary instance, the scaling process for the acquired oil pressure signal includes:

[0017] The acquired oil pressure signals are processed to differentiate between the various oil pressure signal values;

[0018] The oil pressure signals after the differences between the various oil pressure signal values ​​are normalized.

[0019] In one exemplary instance, processing the acquired oil pressure signals to widen the gap between the various oil pressure signal values ​​includes:

[0020] Each oil pressure signal value included in the acquired oil pressure signal is processed to the fourth power.

[0021] In one exemplary instance, the normalization process includes: Where, x i This indicates that the collected oil pressure signal includes the oil pressure signal values ​​i, i = 1, 2, ... n after normalization. n This indicates the oil pressure information after the fourth power processing: oil n =[(x1) 4 (x2) 4 ,......(x n ) 4 ].

[0022] In one exemplary instance, extracting the location of the fuel injection peak using the sliding window algorithm includes:

[0023] The sliding window algorithm is used to segment the scaled oil pressure signal and locate the position of the maximum range in each window.

[0024] The results of segmented processing are sorted, and the maximum value of the range is determined as the injection peak threshold. The maximum value of the range that exceeds the injection peak threshold is determined as the injection peak value.

[0025] In one exemplary instance, the segmentation processing of the scaled hydraulic signal using a sliding window algorithm includes:

[0026] Based on the engine's injection angle θ and the engine's maximum speed N max Given the sampling rate fs, calculate the minimum window length L;

[0027] The scaled hydraulic signal is divided into a preset number of segments according to the minimum window length L. The sliding window passes through the range of the hydraulic signal.

[0028] In one exemplary instance, the minimum window length L is:

[0029] In one exemplary instance, sorting the results of the segmented processing and obtaining the maximum value of the judgment range as the injection peak threshold includes:

[0030] The range values ​​within all the sliding windows are counted and sorted from largest to smallest. The range values ​​determined according to the preset selection rules are used as the fuel injection peak threshold.

[0031] In one exemplary instance, the preset selection rule includes: the peak injection threshold is the value of p% of the m-th range value in the direction from the minimum range value to the maximum range value.

[0032] This application also provides a computer-readable storage medium storing computer-executable instructions for executing any of the above-described engine duty cycle detection methods.

[0033] This application embodiment further provides an apparatus for realizing engine duty cycle detection, including a memory and a processor, wherein the memory stores the following instructions executable by the processor: for performing the steps of the engine duty cycle detection method described in any of the above claims.

[0034] This application embodiment provides another engine duty cycle detection device, including: a data acquisition module, a processing module, a determination module, and a positioning module; wherein,

[0035] The acquisition module is used to acquire the engine's oil pressure signal and vibration signal. The oil pressure signal is acquired by an oil pressure sensor installed on the cylinder that performs the first work cycle of the engine.

[0036] The processing module is used to scale the acquired oil pressure signal to reduce invalid signals and amplify valid signals.

[0037] The determination module is used to extract the location of the injection peak value based on the scaled oil pressure signal using a sliding window algorithm.

[0038] The positioning module is used to map the location of the extracted fuel injection peak onto the collected vibration signal to locate the power stroke of each cylinder and the opening and closing impact of the intake and exhaust valves within a working cycle.

[0039] In one exemplary instance, the determining module is further configured to: perform outlier removal processing on the location of the extracted fuel injection peak.

[0040] This application also provides an engine, including an oil pressure sensor disposed on the cylinder that performs work first in an engine working cycle, at least one vibration sensor for collecting vibration signals of the engine, and the engine working cycle detection device described in any of the above.

[0041] In one exemplary instance, the engine is a V6 engine;

[0042] The oil pressure sensor is installed on the fuel injection pipe of cylinder 1 of the V6 engine;

[0043] The vibration sensors are installed on the cylinder head surfaces of cylinders 2 and 5 of the V6 engine.

[0044] Through the embodiments of this application, oil pressure signals are collected from the cylinder that performs power first in an engine working cycle. This is simple and more conducive to accurately locating the power stroke and intake / exhaust valve seating positions of each cylinder in a working cycle. Moreover, the collected oil pressure signals are scaled, which optimizes the original collected oil pressure signals without changing the peak position. This achieves the purpose of reducing invalid signals and amplifying valid signals. Furthermore, the sliding window algorithm is used to better locate each working cycle of the engine, accurately pinpointing the intake / exhaust valve seating positions and the impact positions generated by power stroke in each cylinder of the engine. This provides a strong guarantee for subsequent engine fault diagnosis.

[0045] Furthermore, the embodiments of this application further perform outlier removal processing on the fuel injection peak value in the same working cycle, thereby obtaining a more accurate fuel injection peak value position. This avoids the problem of false judgment caused by dividing the fuel injection peak value in the same working cycle into two working cycles, and more accurately realizes the positioning of each working cycle of the engine. It also more accurately locates the position of the intake and exhaust valves of each cylinder of the engine and the impact position generated by the power stroke, providing a stronger guarantee for subsequent engine fault diagnosis.

[0046] It accurately locates the power output of each cylinder of the engine and the impact of the opening and closing of the intake and exhaust valves within a working cycle.

[0047] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0048] The accompanying drawings are used to provide a further understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0049] Figure 1 This is a flowchart illustrating the engine duty cycle detection method in the embodiments of this application;

[0050] Figure 2(a) is a schematic diagram of the internal structure of the V6 engine in an embodiment of this application;

[0051] Figure 2(b) is a schematic diagram of the location of the sensor installed on the V6 engine in an embodiment of this application;

[0052] Figure 3 This is a schematic diagram of the sampled hydraulic pressure data waveform and vibration data waveform in the embodiments of this application;

[0053] Figure 4 This is a schematic diagram comparing the hydraulic pressure data waveforms before and after processing of the sampled elegant signal in the embodiments of this application;

[0054] Figure 5 This is a waveform diagram of the hydraulic signal conversion embodiment after sliding window processing in this application.

[0055] Figure 6 This is a waveform diagram of the fuel injection peak positioning result embodiment in this application.

[0056] Figure 7(a) is a schematic diagram of the position of each cycle of the 1s vibration data in the embodiment of this application;

[0057] Figure 7(b) is a schematic diagram of the power position of each cylinder and the seat position of the intake and exhaust valves in a working cycle as defined in the embodiments of this application.

[0058] Figure 8 This is a flowchart illustrating one embodiment of the engine duty cycle detection method in this application.

[0059] Figure 9(a) is a schematic diagram of the peak position of fuel injection before the rejection process was performed in the embodiment of this application;

[0060] Figure 9(b) is a schematic diagram of the position of the injection peak after the rejection process in the embodiment of this application;

[0061] Figure 10 This is a schematic diagram of the composition of the engine working cycle detection device in the embodiments of this application. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be arbitrarily combined with each other.

[0063] In a typical configuration of this application, the computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0064] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0065] Computer-readable media include both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include non-transitory computer-readable media, such as modulated data signals and carrier waves.

[0066] The steps illustrated in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases the steps shown or described may be performed in a different order than that presented here.

[0067] Figure 1 This is a flowchart illustrating the engine duty cycle detection method in an embodiment of this application, as shown below. Figure 1 As shown, it includes:

[0068] Step 100: Collect the engine's oil pressure signal and vibration signal. The oil pressure signal is collected by an oil pressure sensor installed on the cylinder that performs the first work cycle of the engine.

[0069] In one exemplary instance, the vibration signal in step 100 can be acquired by a vibration sensor mounted on the engine. The mounting position of the vibration sensor on the engine can be determined based on numerous experiments. Taking a V6 engine as an example, the vibration sensor may include two sensors, mounted on the cylinder head surfaces of cylinders 2 and 5, respectively. Figure 2(a) is a schematic diagram of the internal structure of a V6 engine in an embodiment of this application. In one embodiment, as shown in Figure 2(b), the oil pressure sensor is mounted on the fuel injection pipe of cylinder 1 of the V6 engine, and the two vibration sensors are mounted on the cylinder head surfaces of cylinders 2 and 5 of the V6 engine, respectively.

[0070] In one exemplary instance, engine oil pressure and vibration signals can be acquired at a preset sampling frequency, such as 100kHz. Taking a sampling duration of 2 seconds for each data set as an example, N sets of data from the oil pressure sensor and vibration sensor are obtained, with waveform samples of both types of sensor data as shown below. Figure 3 As shown, the first row displays the waveform of the oil pressure signal, while the second and third rows display the cylinder head vibration signal waveforms of cylinders 2 and 5, respectively.

[0071] In one exemplary instance, taking a V6-cylinder engine as an example, this application embodiment uses an oil pressure sensor to collect the fuel injection pipe pressure signal of cylinder 1 instead of measuring the flywheel speed signal in related technologies. In this way, it is only necessary to clamp the oil pressure sensor on the fuel injection pipe of cylinder 1, without having to find the location separately. Moreover, cylinder 1 is the first cylinder to do power in an engine working cycle, which is more conducive to accurately locating the power operation of each cylinder and the seating position of the intake and exhaust valves in a working cycle.

[0072] Step 101: The acquired oil pressure signal is scaled to reduce invalid signals and amplify valid signals.

[0073] According to the engine's working principle, the fuel line connected to cylinder 1 injects fuel each time, signifying that cylinder 1 enters its power stroke. This is reflected on the fuel pressure sensor as a pressure peak. The peak value is symmetrical about the x-axis, and the interval between two peaks constitutes one engine working cycle. To pinpoint the peak location, a peak value threshold T is typically set. Peak values ​​exceeding this threshold T are considered the peak values ​​at the injection point. However, if... Figure 3 As shown, during vehicle operation, the sudden decrease in fuel injection peak value can occur due to the continuous changes in gear and throttle. By setting a fixed peak value threshold T, the sudden decrease in fuel injection peak value will not be recognized, thus causing the problem of missed detection.

[0074] Therefore, in this embodiment, step 101 scales the acquired oil pressure signal to reduce invalid signals and amplify valid signals. In one exemplary instance, scaling the acquired oil pressure signal in step 101 includes:

[0075] The collected oil pressure signals are processed to differentiate between the various oil pressure signal values;

[0076] The oil pressure signals after the differences between the various oil pressure signal values ​​are normalized.

[0077] By scaling the acquired oil pressure signal in this step, the original acquired oil pressure signal can be optimized without changing the peak position, thereby reducing invalid signals and amplifying valid signals.

[0078] In one exemplary instance, assume the original acquired oil pressure signal is oil = [x1, x2, ..., x...]. nTo differentiate the oil pressure signal values, the process involves processing the acquired oil pressure signals to the fourth power. For example, the oil pressure information after fourth power processing is: oil... n =[(x1) 4 (x2) 4 ,......(x n ) 4 This widens the gap between the various oil pressure signal values; then, the fourth-order processed oil pressure signal is normalized to obtain... Where i = 1, 2, ..., n.

[0079] Figure 4 This is a schematic diagram comparing the oil pressure data waveforms of the sampled oil pressure signals before and after processing in an embodiment of this application. Figure 4 As shown, the upper part is the original oil pressure signal waveform, and the lower part is the oil pressure signal waveform after processing in step 101. After processing in step 101, the original oil pressure signal is well optimized without changing the peak position, achieving the purpose of reducing invalid signals and amplifying valid signals, which is beneficial for fuel injection peak detection. Taking the situation where the fuel injection peak suddenly decreases due to the continuous changes in gear and throttle during vehicle operation as an example, the scaling processing of the oil pressure signal in step 101 reduces invalid signals and amplifies valid signals. By setting a fixed peak threshold T, the problem of not being able to identify suddenly decreased fuel injection peaks is avoided, and missed detections are also prevented.

[0080] Step 102: Based on the scaled oil pressure signal, use the sliding window algorithm to extract the location of the injection peak.

[0081] In one exemplary instance, step 102 may include:

[0082] The sliding window algorithm is used to segment the scaled oil pressure signal and locate the position of the maximum range in each window.

[0083] The results of segmented processing are sorted, and the maximum value of the range is determined as the injection peak threshold. The maximum value of the range that exceeds the injection peak threshold is determined as the injection peak value.

[0084] In one exemplary instance, segmenting the scaled hydraulic signal using a sliding window algorithm may include:

[0085] Based on the injection angle θ and the engine's maximum speed N max Given the sampling rate fs, the minimum window length L can be calculated using the following formula: In one embodiment, the minimum window length L = 1000.

[0086] The scaled hydraulic signal is divided into a preset number of parts, such as 20 parts, according to a minimum window length L (e.g., 1000). The window slides along the x-axis, and the amplitude values ​​traversed by the window are set as the range values ​​of the hydraulic signal. A schematic diagram of the hydraulic signal conversion embodiment is shown below. Figure 5 As shown, Figure 5 In the diagram, the upper waveform is the scaled hydraulic signal waveform, and the lower waveform is the range waveform of the hydraulic signal after sliding window segmentation.

[0087] In one exemplary instance, sorting the results of segmented processing and obtaining the maximum value of the judgment range as the injection peak threshold may include:

[0088] According to a preset selection rule, one of the range values ​​within all sliding windows is selected as the fuel injection peak threshold. In one embodiment, the range values ​​within all sliding windows are statistically analyzed and sorted from largest to smallest. The value of p% of the m-th range value from smallest to largest is then selected as the fuel injection peak threshold according to a preset selection rule. In another embodiment, 30% of the second-to-last value among the range values ​​within the sliding windows arranged from largest to smallest can be used as the fuel injection peak threshold. Thus, any peak value exceeding this threshold is defined as the fuel injection peak value. The fuel injection peak value positioning result is as follows: Figure 6 As shown, Figure 6 In the diagram, "*" indicates the beginning of a work cycle, and "·" indicates the end of a work cycle. Figure 6 In the diagram, the upper waveform is the scaled-down oil pressure signal waveform, and the lower waveform is the injection peak positioning result waveform.

[0089] The embodiments of this application achieve better positioning of each working cycle of the engine through the sliding window algorithm, accurately locating the seating position of the intake and exhaust valves of each cylinder and the impact position generated by the power stroke, providing a strong guarantee for subsequent engine fault diagnosis.

[0090] Step 103: Map the location of the extracted fuel injection peak onto the collected vibration signal to locate the power stroke of each cylinder and the opening and closing impact of the intake and exhaust valves within a working cycle.

[0091] In an exemplary instance, taking a V6 engine as an example, the location of the injection peak extracted in step 102, i.e., the located injection peak position, is mapped to the vibration signals of cylinders 2 and 5. This allows for the accurate location of the power stroke position and intake / exhaust valve seating position of each cylinder in a working cycle, as shown in Figure 7(b). Figure 7(a) shows the position 801 of each cycle of the 1s vibration data. Taking the third cycle and magnifying it locally, we get Figure 7(b). Combined with the schematic diagram of the V6 engine, it can be seen that in the vibration signal of cylinder 2, the relatively obvious injection peaks in one cycle are the power stroke impacts of cylinders 1, 2, and 3. In the vibration signal of cylinder 5, the relatively obvious injection peaks in one cycle are the power stroke impacts of cylinders 4, 5, and 6. The valve seating position can also be deduced based on the interval between the power stroke and the valve seating position, which provides a useful basis for subsequent engine misfire and valve fault diagnosis.

[0092] The engine working cycle detection method provided in this application collects oil pressure signals on the cylinder that performs power first in an engine working cycle. This method is simple to implement and more conducive to accurately locating the power and intake / exhaust valve positions of each cylinder in a working cycle. Moreover, the collected oil pressure signals are scaled, which optimizes the original collected oil pressure signals without changing the peak position. This achieves the purpose of reducing invalid signals and amplifying valid signals. Furthermore, the sliding window algorithm is used to better locate each working cycle of the engine, accurately pinpointing the intake / exhaust valve positions and the impact positions generated by power stroke in each cylinder. This provides a strong guarantee for subsequent engine fault diagnosis.

[0093] In one exemplary instance, such as Figure 8 As shown, the engine working cycle detection method provided in this application embodiment may further include step 1021: performing outlier removal processing on the location of the fuel injection peak extracted in step 102.

[0094] After verifying with a large amount of hydraulic pressure data, the inventors of this application discovered that during actual vehicle operation, interference caused by inaccurate installation of the hydraulic pressure sensor or other abnormalities can lead to irregular fuel injection peak patterns, resulting in a repositioning phenomenon. In other words, fuel injection peaks within the same working cycle are divided into two working cycles, leading to false judgments. Figure 6 As shown in the waveform above, in order to improve data utilization and save acquisition costs, this embodiment of the application further includes outlier removal processing on the location of the fuel injection peak extracted in step 102, which may include:

[0095] The maximum engine speed N is obtained based on the engine's own parameters. max The minimum speed N during normal driving min ;

[0096] Based on the sampling rate, the maximum rotational speed N max and minimum speed N min The value is used to calculate the number of sampling points T corresponding to the maximum time length in a work cycle. max The number of sampling points T corresponding to the minimum time length min The calculation formula is shown in formula (1):

[0097]

[0098] The number of sampling points T corresponding to the calculated maximum time length max The number of sampling points T corresponding to the minimum time length min To optimize the peak injection position, the difference between the end position (marked by "·") and the start position (marked by "*") of a certain work cycle must be greater than the maximum time length corresponding to the number of sampling points T. max Or less than the number of sampling points T corresponding to the minimum time length min If the outlier is not found, the position is removed. The optimized result is shown in Figure 9(b). Figure 9(a) is a schematic diagram of the injection peak position before the removal process. Comparing Figure 9(a) and Figure 9(b), it can be seen that after removing the outlier, the injection peak position of cylinder 1 within a sampling time of 2 seconds is accurately obtained. This avoids the problem of injection peaks in the same working cycle being divided into two working cycles, resulting in false judgments. Furthermore, it more accurately realizes the positioning of each working cycle of the engine, and more accurately locates the intake and exhaust valves of each cylinder of the engine and the impact position generated by the power stroke, providing a stronger guarantee for subsequent engine fault diagnosis.

[0099] This application also provides a computer-readable storage medium storing computer-executable instructions for performing the engine duty cycle detection method described in any of the above claims.

[0100] This application further provides an apparatus for realizing engine duty cycle detection, including a memory and a processor, wherein the memory stores the following instructions executable by the processor for performing the steps of the engine duty cycle detection method described in any of the above claims.

[0101] Figure 10 This is a schematic diagram of the composition of the engine working cycle detection device in the embodiments of this application, as shown below. Figure 10 As shown, it includes: a data acquisition module, a processing module, a determination module, and a positioning module; among which,

[0102] The acquisition module is used to acquire the engine's oil pressure signal and vibration signal. The oil pressure signal is acquired by an oil pressure sensor installed on the cylinder that performs the first work cycle of the engine.

[0103] The processing module is used to scale the acquired oil pressure signal to reduce invalid signals and amplify valid signals.

[0104] The determination module is used to extract the location of the injection peak value based on the scaled oil pressure signal using a sliding window algorithm.

[0105] The positioning module is used to map the location of the extracted fuel injection peak onto the collected vibration signal to locate the power stroke of each cylinder and the opening and closing impact of the intake and exhaust valves within a working cycle.

[0106] The engine working cycle detection device provided in this application collects oil pressure signals on the cylinder that performs power first in an engine working cycle. This is simple to implement and more conducive to accurately locating the power and intake / exhaust valve positions of each cylinder in a working cycle. Moreover, the collected oil pressure signals are scaled, which optimizes the original collected oil pressure signals without changing the peak position. This achieves the purpose of reducing invalid signals and amplifying valid signals. Furthermore, the sliding window algorithm better realizes the positioning of each working cycle of the engine, accurately locating the intake / exhaust valve positions and the impact positions generated by power in each cylinder of the engine, providing a strong guarantee for subsequent engine fault diagnosis.

[0107] In one exemplary instance, the processing module can be used to:

[0108] The collected oil pressure signals are processed to widen the gap between the oil pressure signal values; the oil pressure signals after widening the gap between the oil pressure signal values ​​are then normalized.

[0109] By scaling the acquired oil pressure signal, the original acquired oil pressure signal can be optimized without changing the peak position, thereby reducing invalid signals and amplifying valid signals.

[0110] In one exemplary instance, the determination module can be used to:

[0111] The scaling oil pressure signal is segmented using a sliding window algorithm, and the location of the maximum range in each window is determined. The segmented processing results are sorted, and the maximum range is determined as the injection peak threshold. The maximum range exceeding the injection peak threshold is determined as the injection peak value.

[0112] In one embodiment, the process of sorting the results of segmented processing in the determination module and obtaining the maximum value of the range as the injection peak threshold may include: counting the range values ​​in all sliding windows, sorting them from largest to smallest, and using the value of p% of the m-th range value in the direction from smallest to largest as the injection peak threshold according to a preset selection rule.

[0113] In one exemplary instance, the determining module can also be used to: perform outlier removal processing on the location of the extracted fuel injection peak. After removing outliers, this embodiment accurately obtains the fuel injection peak position of cylinder 1 within a sampling timeframe, such as 2 seconds. This avoids the problem of false judgments caused by dividing fuel injection peaks within the same working cycle into two working cycles, and further accurately achieves the positioning of each working cycle of the engine. It also more accurately locates the intake and exhaust valve seating positions and the impact positions generated by the power stroke in each cylinder of the engine, providing a stronger guarantee for subsequent engine fault diagnosis.

[0114] In one exemplary instance, the outlier removal process performed on the location of the extracted fuel injection peak in the determination module may include:

[0115] The maximum engine speed N is obtained based on the engine's own parameters. max The minimum speed N during normal driving min Combined with the sampling rate, the maximum rotational speed N max and minimum speed N min The value is used to calculate the number of sampling points T corresponding to the maximum time length in a work cycle. max The number of sampling points T corresponding to the minimum time length min The number of sampling points T corresponding to the calculated maximum time length. max The number of sampling points T corresponding to the minimum time length min For a given work cycle, the number T of sampling points whose difference between the end and start positions is greater than the maximum time length is excluded. max Or less than the number of sampling points T corresponding to the minimum time length min Location information.

[0116] This application also provides an engine, including an oil pressure sensor disposed on the cylinder that performs work first in an engine working cycle, at least one vibration sensor for collecting vibration signals of the engine, and the engine working cycle detection device described in any of the above.

[0117] In one exemplary instance, the engine is a V6 engine, with an oil pressure sensor located on the fuel injection pipe of cylinder 1 and vibration sensors located on the cylinder head surfaces of cylinders 2 and 5.

[0118] Although the embodiments disclosed in this application are as described above, the content described is merely for the purpose of understanding this application and is not intended to limit this application. Any person skilled in the art to which this application pertains may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in this application; however, the scope of patent protection of this application shall still be determined by the scope defined in the appended claims.

Claims

1. A method for detecting the working cycle of an engine, characterized in that, include: The system collects oil pressure and vibration signals from the engine. The oil pressure signal is collected by an oil pressure sensor installed on the cylinder that performs the first power stroke in one working cycle of the engine; the vibration signal is collected by a vibration sensor installed on the engine. The acquired oil pressure signals are scaled to reduce invalid signals and amplify valid signals; Based on the scaled oil pressure signal, the location of the injection peak is extracted using a sliding window algorithm; Outlier removal is performed on the location of the extracted fuel injection peak. The location of the extracted fuel injection peak is mapped onto the collected vibration signal to locate the power stroke of each cylinder and the opening and closing impact of the intake and exhaust valves within a working cycle. The step of using a sliding window algorithm to extract the location of the fuel injection peak includes: Based on the engine's injection angle θ and the engine's maximum speed and sampling rate Calculate the minimum window length L; The scaled hydraulic signal is divided into a preset number of segments according to the minimum window length L. The sliding window passes through the range of the hydraulic signal. Locate the position of the maximum range in each window; The range values ​​within all the windows are counted and sorted from largest to smallest. The range value determined according to the preset selection rule is used as the fuel injection peak threshold. The maximum range value exceeding the fuel injection peak threshold is determined as the fuel injection peak value. The preset selection rule includes: the fuel injection peak threshold is the value of p% of the m-th range value from the minimum range value to the maximum range value.

2. The engine working cycle detection method according to claim 1, wherein, The outlier removal process for the extracted fuel injection peak locations includes: Obtain the maximum speed of the engine and the minimum speed during normal driving ; Combined sampling rate Maximum speed and minimum speed Calculate the number of sampling points corresponding to the maximum time length in a work cycle. The number of sampling points corresponding to the minimum time length ,in, ; Based on the number of sampling points corresponding to the calculated maximum time length The number of sampling points corresponding to the minimum time length For a work cycle, the number of sampling points whose difference between the end and start positions is greater than the maximum time length is eliminated. Or the difference between its end position and start position is less than the number of sampling points corresponding to the minimum time length. Location information.

3. The engine duty cycle detection method according to claim 1, wherein, The scaling process for the acquired oil pressure signal includes: The acquired oil pressure signals are processed to differentiate between the various oil pressure signal values; The oil pressure signals after the differences between the various oil pressure signal values ​​are normalized.

4. The engine duty cycle detection method according to claim 3, wherein, The process of processing the acquired oil pressure signals to differentiate between the various oil pressure signal values ​​includes: Each oil pressure signal value included in the acquired oil pressure signal is processed to the fourth power.

5. The engine duty cycle detection method according to claim 4, wherein, The normalization process includes: ,in, This indicates that the collected oil pressure signal includes the oil pressure signal values ​​i, i=1,2,…n after normalization. This indicates the oil pressure information after the fourth power processing: .

6. The engine duty cycle detection method according to claim 1, wherein, The minimum window length L is: .

7. A computer-readable storage medium storing computer-executable instructions for performing the engine duty cycle detection method according to any one of claims 1-6.

8. A device for detecting engine duty cycles, comprising a memory and a processor, wherein, The memory stores the following instructions that can be executed by a processor: for performing the steps of the engine duty cycle detection method according to any one of claims 1-6.

9. An engine working cycle detection device, characterized in that, The engine working cycle detection method according to any one of claims 1-6 is used, comprising: a data acquisition module, a processing module, a determination module, and a positioning module; wherein, The acquisition module is used to acquire the engine's oil pressure signal and vibration signal. The oil pressure signal is acquired by an oil pressure sensor installed on the cylinder that performs the first work cycle in the engine; the vibration signal is acquired by a vibration sensor installed on the engine. The processing module is used to scale the acquired oil pressure signal to reduce invalid signals and amplify valid signals. The determination module is used to extract the location of the injection peak value based on the scaled oil pressure signal using a sliding window algorithm; and to perform outlier removal processing on the extracted injection peak value location. The positioning module is used to map the location of the extracted fuel injection peak onto the collected vibration signal to locate the power stroke of each cylinder and the opening and closing impact of the intake and exhaust valves within a working cycle.

10. An engine, characterized in that, It includes an oil pressure sensor installed on the cylinder that performs the first work in an engine working cycle, at least one vibration sensor for collecting vibration signals from the engine, and the engine working cycle detection device as described in claim 9.

11. The engine according to claim 10, wherein, The engine is a V6 engine; The oil pressure sensor is installed on the fuel injection pipe of cylinder 1 of the V6 engine; The vibration sensors are installed on the cylinder head surfaces of cylinders 2 and 5 of the V6 engine.

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