WO2021195948A1 - 发动机的失火检测方法、装置、设备、存储介质和程序 - Google Patents

发动机的失火检测方法、装置、设备、存储介质和程序 Download PDF

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Publication number
WO2021195948A1
WO2021195948A1 PCT/CN2020/082391 CN2020082391W WO2021195948A1 WO 2021195948 A1 WO2021195948 A1 WO 2021195948A1 CN 2020082391 W CN2020082391 W CN 2020082391W WO 2021195948 A1 WO2021195948 A1 WO 2021195948A1
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Prior art keywords
engine
amplitude
order harmonic
speed signal
harmonic component
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PCT/CN2020/082391
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English (en)
French (fr)
Inventor
谭治学
刘翀
梁健星
杨新达
潘永传
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潍柴动力股份有限公司
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Priority to PCT/CN2020/082391 priority Critical patent/WO2021195948A1/zh
Publication of WO2021195948A1 publication Critical patent/WO2021195948A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M15/00—Testing of engines
    • G01M15/04—Testing internal-combustion engines
    • G01M15/11—Testing internal-combustion engines by detecting misfire

Definitions

  • This application relates to the field of traffic technology, and in particular to an engine misfire detection method, device, equipment, storage medium and program.
  • in-line engines are usually installed in vehicles, for example, in-line 6-cylinder engines, in-line 8-cylinder engines, and so on.
  • misfire phenomenon when the engine is running, the mixed gas in the cylinder of the engine may not be ignited, and this phenomenon is called a misfire phenomenon.
  • the present application provides an engine misfire detection method, device, equipment, storage medium, and program, which are easy to implement misfire detection on the engine, and thus can greatly avoid component damage.
  • this application provides an engine misfire detection method, including:
  • misfire detection is performed on the engine.
  • performing spectrum analysis processing on the rotational speed signal in the target duty cycle to obtain the amplitude of the multi-order harmonic components corresponding to the rotational speed signal in the target duty cycle includes:
  • performing misfire detection on the engine according to the amplitude of the multi-order harmonic components includes:
  • the first characteristic value is greater than a first preset threshold, it is determined that the engine is misfired.
  • the method further includes:
  • the second characteristic value is determined according to the amplitude of the second-order harmonic component and the amplitude of the K-order harmonic component, where the value of K is All odd numbers greater than 1 and less than M;
  • the second characteristic value is greater than a second preset threshold, it is determined that a symmetrical cylinder misfire has occurred in the engine; if the second characteristic value is less than or equal to the second preset threshold, it is determined that the engine has not misfired.
  • the second characteristic value is (the amplitude of the second-order harmonic component + the amplitude of the fourth-order harmonic component)/[(the amplitude of the third-order harmonic component + the fifth-order The amplitude of the harmonic component+a)-the amplitude of the sixth-order harmonic component/(the amplitude of the second-order harmonic component+the amplitude of the fourth-order harmonic component+b)], where a is the preset first Value, b is the preset second value.
  • the method further includes:
  • the third characteristic value is greater than the third preset threshold, it is determined that a spaced cylinder misfire occurs in the engine.
  • the method further includes:
  • a fourth characteristic value is determined, where the fourth characteristic value is the amplitude of the first-order harmonic component/[1/(2/M ) The amplitude of the first-order harmonic component+c)], or, the amplitude of the first-order harmonic component/(the amplitude of the M-order harmonic component+c), where c is the preset third value;
  • the fourth characteristic value is greater than the fourth preset threshold, it is determined that the engine has a misfire in adjacent cylinders; if the fourth characteristic value is less than or equal to the fourth preset threshold, it is determined that the engine has a single-cylinder misfire. Fire.
  • the method further includes:
  • the performing Fourier transform on the rotational speed signal in the target duty cycle includes:
  • the method further includes:
  • the performing Fourier transform on the rotational speed signal after de-reversing drag includes:
  • an engine misfire detection device including:
  • An obtaining unit configured to obtain a rotation speed signal of the engine in a target working cycle
  • a processing unit configured to perform spectrum analysis processing on the rotational speed signal in the target work cycle to obtain the amplitude of the multi-order harmonic component corresponding to the rotational speed signal in the target work cycle;
  • the detection unit is configured to perform misfire detection on the engine according to the amplitude of the multi-order harmonic components.
  • the processing unit is specifically configured to perform Fourier transform on the rotational speed signal in the target duty cycle to obtain the amplitude of the first to M order harmonic components corresponding to the rotational speed signal in the target duty cycle ,
  • M is the number of cylinders in the engine, and M is a positive integer greater than 2.
  • the detection unit is specifically configured to determine the ratio of the amplitude of the first-order harmonic component to the amplitude of the M-order harmonic component, which is the first characteristic value; if the first characteristic value is greater than the first preset Threshold, it is determined that the engine is misfired.
  • the detection unit is further configured to, if the first characteristic value is less than or equal to the first preset threshold, determine the second harmonic component according to the amplitude of the second-order harmonic component and the amplitude of the K-order harmonic component. Two eigenvalues, where the value of K is all odd numbers greater than 1 and less than M; if the second eigenvalue is greater than a second preset threshold, it is determined that the engine has a symmetrical cylinder misfire; if the second characteristic If the value is less than or equal to the second preset threshold, it is determined that no misfire has occurred in the engine.
  • the second characteristic value is (the amplitude of the second-order harmonic component + the amplitude of the fourth-order harmonic component)/[(the amplitude of the third-order harmonic component + the fifth-order The amplitude of the harmonic component+a)-the amplitude of the sixth-order harmonic component/(the amplitude of the second-order harmonic component+the amplitude of the fourth-order harmonic component+b)], where a is the preset first Value, b is the preset second value.
  • the detection unit is further configured to determine a fourth characteristic value when the third characteristic value is less than or equal to the third preset threshold, wherein the fourth characteristic value is a first-order harmonic The amplitude of the component/[1/(2/M)-order harmonic component's amplitude+c)], or the first-order harmonic component's amplitude/(M-order harmonic component's amplitude+c), where , C is the preset third value; if the fourth characteristic value is greater than the fourth preset threshold, it is determined that the engine has a misfire in adjacent cylinders; if the fourth characteristic value is less than or equal to the fourth preset threshold , It is determined that a single-cylinder misfire has occurred in the engine.
  • processing unit is further configured to remove the backward drag signal in the rotation speed signal in the target duty cycle before performing Fourier transform on the rotation speed signal in the target duty cycle, so as to obtain the de-reverse drag signal.
  • the processing unit is specifically configured to perform Fourier transform on the rotational speed signal after de-reverse dragging.
  • the processing unit is further configured to: after removing the reverse drag signal in the rotational speed signal in the target duty cycle, and before performing Fourier transform on the rotational speed signal after the reverse drag, according to the The speed signal in the target working cycle determines the average speed of the engine in the target working cycle; acquiring the average speed of the engine in the previous working cycle of the target working cycle; The average rotation speed in the target working cycle, the average rotation speed in the previous working cycle, and the number of teeth of the test ring gear of the engine are used to determine the trend item to be rejected; Trend item, get the speed signal after de-trend item;
  • the processing unit is specifically configured to perform Fourier transform on the rotational speed signal after the detrending term.
  • an engine misfire detection equipment including: a memory and a processor;
  • the memory is used to store a computer program
  • the processor executes the computer program in the memory to implement any method of the first aspect.
  • the present application provides a computer-readable storage medium in which a computer-executable instruction is stored, and the computer-executable instruction is used to implement any method of the first aspect when the computer-executable instruction is executed by a processor.
  • the present application provides a computer program, including program code.
  • the program code executes any method as in the first aspect.
  • the engine misfire detection method, device, equipment, storage medium, and program provided in this application obtain the engine speed signal in the target working cycle, and then perform spectral analysis and processing on the speed signal to obtain the amplitude of the multi-order harmonic components , And then can detect whether the engine misfires according to the amplitude of the obtained multi-order harmonic components, and then relevant maintenance measures can be carried out in time to avoid damage to the three-way catalyst as much as possible.
  • Figure 1 is a schematic structural diagram of a vehicle provided in the prior art
  • FIG. 2 is a schematic flowchart of a method for detecting misfire of an engine provided in Embodiment 1 of the application;
  • FIG. 3 is a schematic flowchart of a method for detecting misfire of an engine provided in the second embodiment of the application;
  • FIG. 4 is a schematic flowchart of a method for detecting misfire of an engine provided in Embodiment 3 of the application;
  • FIG. 5 is a schematic diagram of the misfire detection result of the engine provided in the third embodiment of the application.
  • Fig. 6 is a schematic structural diagram of an engine misfire detection device provided in the fourth embodiment of the application.
  • FIG. 7 is a schematic structural diagram of an engine misfire detection device provided in Embodiment 5 of the application.
  • the present application provides an engine misfire detection method, device, equipment, storage medium, and program.
  • the engine speed signal By acquiring the engine speed signal in a working cycle, and performing spectrum analysis and processing on the speed signal, the result is processed through the spectrum analysis.
  • the obtained amplitude of the multi-order harmonic components performs misfire detection on the engine, so that when the engine misfire is detected, the driver can be reminded to take necessary maintenance measures to avoid component damage and reduce toxic gas emissions.
  • FIG. 1 is a schematic structural diagram of a vehicle provided in the prior art, and the present application can be applied to the vehicle shown in FIG. 1.
  • Fig. 2 is a schematic flow chart of a method for detecting misfire of an engine provided in the first embodiment of the application. As shown in Fig. 2, the method includes:
  • Step 201 Obtain the speed signal of the engine in the target working cycle.
  • the execution body of this embodiment may be an engine's misfire detection device
  • the engine's misfire detection device may be program software, or may be a medium storing related computer programs, such as a USB flash drive, etc.
  • the fire detection device can also be a physical device integrated or installed with a related computer program, such as a chip, an intelligent terminal, a computer, a server, etc.
  • the device can be installed in a vehicle to detect misfire of an engine that is also installed on the vehicle.
  • a working cycle includes an intake stroke, a compression stroke, a power stroke, and an exhaust stroke. Or, every two revolutions of the crankshaft on the engine, that is, 720 degrees, is a working cycle.
  • the engine speed signal in a working cycle may include multiple instantaneous speed signals. Among them, the engine's instantaneous speed signal can be measured by a speed measuring ring installed at the flywheel end.
  • Step 202 Perform spectrum analysis processing on the rotational speed signal in the target duty cycle to obtain the amplitude of the multi-order harmonic components corresponding to the rotational speed signal in the target duty cycle.
  • the speed signal in the target working cycle (that is, the multiple instantaneous speed signals included) can be subjected to spectrum analysis processing, which is exemplary Yes, fast Fourier Transform (Fast Fourier Transform, FFT for short) can be performed on the rotational speed signal in the target duty cycle, so that the amplitude of the multi-order harmonic components can be obtained.
  • the amplitude of the multi-order harmonic component may include the amplitude of the first-order harmonic component, the amplitude of the second-order harmonic component... the amplitude of the Q-order harmonic component, etc., where Q is For a positive integer greater than 1, the value of Q can be set according to actual needs.
  • Step 203 Perform misfire detection on the engine according to the amplitude of the multi-order harmonic components.
  • the present application provides a method for detecting misfire of an engine.
  • the amplitude of the multi-order harmonic components can be obtained.
  • the amplitude of the first-order harmonic component can detect whether the engine misfires, and then relevant maintenance measures can be carried out in time to avoid damage to the three-way catalytic converter as much as possible.
  • Fig. 3 is a schematic flow chart of a method for detecting misfire of an engine provided in the second embodiment of the application. As shown in Fig. 3, the method includes:
  • Step 301 Obtain the speed signal of the engine in the target working cycle.
  • step 201 in the first embodiment can refer to step 201 in the first embodiment, which will not be repeated here.
  • the speed signal in the target working cycle may include multiple instantaneous speed signals, wherein the instantaneous speed signal of the engine can be calculated by the following formula (1).
  • S RPM is the instantaneous speed signal of the engine
  • N tooth is the number of teeth of the speed measuring ring gear of the engine
  • ⁇ t is the tooth period.
  • the number of teeth N tooth of the test gear ring should be no less than 60, and the number of significant digits of ⁇ t should be no less than 4 digits.
  • the engine speed signal in the target working cycle i can be obtained Among them, a total of 2N tooth instantaneous speed signals are included.
  • step 301 is executed. For example, when it is determined that the vehicle where the engine is located is not in an uphill or downhill scene, the execution of step 301 is triggered.
  • Step 302 Remove the reverse drag signal from the rotation speed signal in the target work cycle, and obtain the rotation speed signal after the reverse drag is removed.
  • the work done by the gas in the cylinder of the engine will cause the engine to generate a speed signal.
  • the friction of the piston, or the inertial elements of the engine, the connecting rod, etc. will also produce a part of the speed signal, and this part of the speed signal is the reverse drag signal.
  • the reverse drag signal is equivalent to the background noise of the speed signal, which has obvious interference in detecting whether the engine is misfired. Therefore, the reverse drag signal in the speed signal should be removed to improve the accuracy of engine misfire detection.
  • each instantaneous rotational speed signal should be subjected to de-reversing signal processing. Specifically, it can be calibrated by measuring the amplitude and phase at each rotation speed, and based on this, the backward drag signal is removed. In addition, it can also be removed by other existing technologies, and will not be further described here.
  • Step 303 Determine the average speed of the engine in the target working cycle according to the speed signal in the target working cycle, and obtain the average speed of the engine in the previous working cycle of the target working cycle, according to the average speed of the engine in the target working cycle , The average speed in the last working cycle, and the number of teeth of the test gear ring of the engine, determine the trend item to be eliminated, and eliminate the trend item in the speed signal after the reverse drag, and get the speed signal after the trend item.
  • the speed trend change component of the engine should be eliminated, that is, the trend item to be eliminated.
  • the trend item to be eliminated can be calculated by the following formula (2).
  • S trend is the trend item to be removed
  • [1,2,...,2N tooth ] is a vector.
  • Step 304 Perform Fourier transform on the rotational speed signal after the detrending term, and obtain the amplitude of the first to M order harmonic components corresponding to the rotational speed signal in the target working cycle, where M is the number of cylinders of the engine, and M It is a positive integer greater than 2.
  • the speed signal after removing the trend item is obtained as After that, for those containing 2N tooth processed instantaneous speed signals Carry out Fourier transform, specifically, fast Fourier transform can be carried out, so that the amplitude of the harmonic components from the first to the M order can be obtained.
  • Carry out Fourier transform specifically, fast Fourier transform can be carried out, so that the amplitude of the harmonic components from the first to the M order can be obtained.
  • the amplitudes of the first to sixth harmonic components can be extracted; when the engine is an in-line 8-cylinder engine, the amplitudes of the first to eighth harmonic components can be extracted.
  • Step 305 Perform misfire detection on the engine according to the amplitudes of the first to M order harmonic components.
  • the speed signal is processed by the reverse drag signal processing, thereby reducing the interference caused by the reverse drag signal on the misfire detection and improving the accuracy of the misfire detection. Based on this, after getting the speed signal after removing the reverse drag, by eliminating the trend item, the interference caused by the engine to the misfire detection when the engine is accelerating and decelerating can be reduced. Based on the speed signal after the trend item is eliminated, it can be further improved. Accuracy of misfire detection.
  • Fig. 4 is a schematic flow chart of a method for detecting misfire of an engine provided in the third embodiment of the application. As shown in Fig. 4, the method includes:
  • Step 401 Determine the ratio of the amplitude of the first-order harmonic component to the amplitude of the M-order harmonic component, which is the first characteristic value, where M is the number of cylinders of the engine, and M is a positive integer greater than 2.
  • Step 402 Determine whether the first characteristic value is greater than the first preset threshold, if not, perform step 403, if yes, determine that the engine is misfired, and perform step 407.
  • the first preset threshold can be calibrated by conducting a misfire experiment in advance.
  • the first preset threshold may be 0.3. Based on this, after the first characteristic value is determined, it can be compared with the first preset threshold. If the first characteristic value is less than the first preset threshold, it means that the engine has misfired. Cylinder misfire, spacer cylinder misfire, or adjacent cylinder misfire; if the first characteristic value is less than or equal to the first preset threshold, it is necessary to further verify whether a symmetrical cylinder misfire occurs.
  • Figure 5 is a schematic diagram of the misfire detection result of the engine provided in the third embodiment of the application.
  • the right ordinate of the figure is the engine speed signal
  • the left ordinate is the first characteristic value
  • the abscissa is time.
  • the rotational speed signals of the engine in multiple consecutive working cycles can be obtained, and then the rotational speed curve in Fig. 5 is formed according to the rotational speed signals of the engine in these working cycles.
  • each working cycle can correspond to 120
  • the speed signal that is, the speed curve in a working cycle is formed by 120 speed signals in the working cycle.
  • the first characteristic value corresponding to each work cycle can be calculated according to the calculation method in step 401, that is, 120 rotation speed signals correspond to a first characteristic value.
  • the misfire detection result of the engine is intuitively displayed to the user.
  • the user can determine whether the engine has a single-cylinder misfire, a spaced cylinder misfire, or an adjacent cylinder misfire according to FIG. 5 and the first preset threshold.
  • Step 403 Determine a second characteristic value according to the amplitude of the second-order harmonic component and the amplitude of the K-order harmonic component, where the value of K is all odd numbers greater than 1 and less than M.
  • the second characteristic is determined according to the amplitude of the second-order harmonic component and the amplitude of the third-order harmonic component.
  • the amplitude of the wave component determines the second eigenvalue
  • the amplitude of the first-order harmonic component, the amplitude of the fifth-order harmonic component, and the amplitude of the seventh-order harmonic component determine the second eigenvalue.
  • the second characteristic value is (the amplitude of the second-order harmonic component)/[(the amplitude of the third-order harmonic component+a)],
  • a is the preset first value a, which can be 0.1.
  • the second characteristic value is (the amplitude of the second-order harmonic component + the amplitude of the fourth-order harmonic component)/[(the third-order harmonic The amplitude of the component + the amplitude of the fifth-order harmonic component + a)-the amplitude of the sixth-order harmonic component / (the amplitude of the second-order harmonic component + the amplitude of the fourth-order harmonic component + b)], where , A is the preset first value, and b is the preset second value.
  • the value of a and b can be 0.1.
  • the second characteristic value is (the amplitude of the second-order harmonic component)/[(the amplitude of the third-order harmonic component + the fifth-order harmonic
  • a is the preset first value a may take the value of 0.1.
  • Step 404 Determine whether the second characteristic value is greater than the second preset threshold, if yes, execute step 405, and if not, execute step 406.
  • the second preset threshold is also pre-calibrated.
  • the second preset threshold may be 0.4. Based on this, after the second characteristic value is determined, it can be compared with the second preset threshold. If the second characteristic value is greater than the second preset threshold, it means that the engine has a symmetrical cylinder misfire; if the second characteristic value is If it is less than or equal to the second preset threshold, it means that the engine has not misfired.
  • Step 405 Determine that a symmetrical cylinder misfire occurs in the engine.
  • the first-order harmonic component when a symmetrical cylinder misfire occurs in the engine, the first-order harmonic component will be masked by the second-order harmonic component. Therefore, it is necessary to additionally determine whether it is a symmetrical cylinder misfire.
  • Step 406 It is determined that no misfire has occurred in the engine.
  • Step 408 Determine whether the third characteristic value is greater than the third preset threshold, if yes, execute step 409, if not, execute step 410.
  • the third preset threshold is also pre-calibrated. Based on this, after the third characteristic value is determined, it can be compared with the third preset threshold. If the third characteristic value is greater than the third preset threshold, it means that the engine has a misfire in the interval cylinder; if the third characteristic value is If it is less than or equal to the third preset threshold, it is also necessary to determine whether the engine misfires in adjacent cylinders.
  • Step 409 Determine that a spacer cylinder misfire occurs in the engine.
  • Step 410 Determine a fourth eigenvalue, where the fourth eigenvalue is the amplitude of the first-order harmonic component/[1/(2/M)-order harmonic component's amplitude+c)], or the first-order The amplitude of the harmonic component/(the amplitude of the M-order harmonic component+c), where c is the preset third value.
  • the value of c can be 0.1.
  • Step 411 Determine whether the fourth characteristic value is greater than the fourth preset threshold, if yes, execute step 412, if not, execute step 413.
  • the fourth preset threshold is also pre-calibrated. Based on this, after the fourth characteristic value is determined, it can be compared with the fourth preset threshold value. If the fourth characteristic value is greater than the fourth preset threshold value, it means that the engine has a misfire in adjacent cylinders; if the fourth characteristic value is If the value is less than or equal to the fourth preset threshold value, it is also necessary to determine that the engine has a single-cylinder misfire.
  • Step 412 Determine that an adjacent cylinder misfire occurs in the engine.
  • Step 413 Determine that a single-cylinder misfire occurs in the engine.
  • the misfire ratio can also be calculated based on the detection result. Specifically, the misfire ratio can be calculated by the following formula (3).
  • ⁇ misfire is the misfire ratio
  • ⁇ I single is the total number of working cycles in which a single-cylinder misfire occurs in the engine
  • ⁇ I double is the total number of working cycles in which the engine misfires in symmetrical cylinders, spaced cylinders, and adjacent cylinders
  • I total is the total number of working cycles.
  • the misfire ratio after the misfire ratio is obtained, it can be determined whether the vehicle is in an emission-damaged misfire or a catalytic converter-damaged misfire according to different thresholds set, so as to remind the driver and take corresponding remedial measures.
  • the first preset threshold, the second preset threshold, the third preset threshold, and the fourth preset can be calibrated in different average speed ranges.
  • Threshold Take an in-line 6-cylinder engine as an example. For it, the average speed interval 1 corresponds to the first preset threshold A, the average speed interval 2 corresponds to the first preset threshold B, and the average speed interval 3 corresponds to the first preset threshold. C corresponds. Assuming that after obtaining the speed signal of the in-line 6-cylinder engine in the target working cycle, the average speed in the target working cycle can be determined.
  • the first characteristic value is compared with the first preset threshold A.
  • preset thresholds please refer to the explanation of the above-mentioned first preset threshold, which will not be explained here too much.
  • the first eigenvalue determined based on the amplitude of the first-order harmonic component and the amplitude of the M-order harmonic component can be used to determine whether a spacer cylinder misfire, a symmetrical cylinder misfire, or a single-cylinder misfire occurs. If not, , Because when a symmetrical cylinder misfire occurs in the engine, the first-order harmonic component will be masked by the second-order harmonic component. Therefore, based on the second-order harmonic component, an additional one is added to determine whether it belongs to a symmetrical cylinder misfire. If it is, then based on the determined third characteristic value, it can be accurately determined whether or not a gap cylinder misfire occurs in the engine. And when it is determined that it is not a misfire in the interval cylinder, based on the amplitude of the first-order harmonic component, it is accurately judged whether the engine has a misfire in the adjacent cylinder.
  • the invention is suitable for the working conditions of the engine with high rotation speed and low load, and can accurately report the misfire fault.
  • the method proposed in the present invention has the characteristics of easy calibration of the judgment threshold, and does not need to be based on the misfire judgment threshold of the engine in different working modes, loads, clutch types, gearbox models, road conditions, and the thresholds according to the working conditions of other accessories.
  • the additional correction work can easily complete the calibration of the first to fourth preset thresholds.
  • these preset thresholds are not sensitive to load changes and speed changes. The same can be used in a wide range of speed and load changes.
  • the threshold value greatly reduces the calibration workload of the On-Board Diagnostic (OBD) system and the memory footprint of the engine controller.
  • OBD On-Board Diagnostic
  • the method proposed by the present invention is not sensitive to changes in engine acceleration and deceleration. Even when the engine is extremely accelerating, the algorithm proposed by the present invention does not produce misfire fault false alarms. Therefore, the method can be applied to unstable vehicle speeds. Working conditions. Furthermore, the method proposed by the present invention has adaptive characteristics, that is, when the engine performance declines, because the method proposed by the present invention does not rely on calculating the change amount of the absolute value of the average effective pressure in the engine cylinder, the engine The performance degradation of the engine is highly adaptable, and it can maintain accuracy after the engine has obvious performance degradation. In addition, the method proposed by the present invention can diagnose the misfire of adjacent cylinders and spacer cylinders at high speeds.
  • the method proposed by the present invention Even at high engine speeds, it can still accurately identify the misfire of the interval cylinder of the engine and the misfire of the adjacent cylinder, and no false alarm or false alarm.
  • FIG. 6 is a schematic structural diagram of an engine misfire detection device provided in the fourth embodiment of the application. As shown in FIG. 6, the device includes: an acquisition unit 601, a processing unit 602, and a detection unit 603. in,
  • the obtaining unit 601 is used to obtain the speed signal of the engine in the target working cycle
  • the processing unit 602 is configured to perform spectrum analysis and processing on the rotational speed signal in the target working cycle to obtain the amplitude of the multi-order harmonic component corresponding to the rotational speed signal in the target working cycle;
  • the detection unit 603 is configured to perform misfire detection on the engine according to the amplitude of the multi-order harmonic components.
  • processing unit 602 is specifically configured to perform Fourier transform on the rotational speed signal in the target duty cycle to obtain the amplitude of the first to M order harmonic components corresponding to the rotational speed signal in the target duty cycle, where M is The number of cylinders the engine has, M is a positive integer greater than 2.
  • the detection unit 603 is specifically configured to determine the ratio of the amplitude of the first-order harmonic component to the amplitude of the M-order harmonic component, which is the first characteristic value; if the first characteristic value is greater than the first preset threshold, then Make sure that the engine has misfired.
  • the detection unit 603 is further configured to determine the second characteristic value according to the amplitude of the second-order harmonic component and the amplitude of the K-order harmonic component if the first characteristic value is less than or equal to the first preset threshold, where , The value of K is all odd numbers greater than 1 and less than M; if the second characteristic value is greater than the second preset threshold, it is determined that a symmetrical cylinder misfire occurs in the engine; if the second characteristic value is less than or equal to the second preset threshold, it is determined The engine did not misfire.
  • the second characteristic value is (the amplitude of the second-order harmonic component + the amplitude of the fourth-order harmonic component)/[(the amplitude of the third-order harmonic component + the fifth-order harmonic The amplitude of the component + a)-the amplitude of the sixth-order harmonic component/(the amplitude of the second-order harmonic component + the amplitude of the fourth-order harmonic component + b)], where a is the preset first value, b is the preset second value.
  • the detection unit 603 is further configured to determine the fourth characteristic value when the third characteristic value is less than or equal to the third preset threshold, where the fourth characteristic value is the amplitude of the first-order harmonic component/[1 /(2/M)-order harmonic component amplitude+c)], or, the first-order harmonic component amplitude/(M-order harmonic component amplitude+c), where c is the preset third Numerical value; if the fourth characteristic value is greater than the fourth preset threshold, it is determined that the engine has an adjacent cylinder misfire; if the fourth characteristic value is less than or equal to the fourth preset threshold, it is determined that the engine has a single-cylinder misfire.
  • processing unit 602 is further configured to remove the reverse drag signal in the rotational speed signal in the target duty cycle before performing Fourier transform on the rotational speed signal in the target duty cycle to obtain the rotational speed signal after the reverse drag is removed;
  • the processing unit 602 is specifically configured to perform Fourier transform on the rotational speed signal after the reverse drag is removed.
  • the processing unit 602 is further configured to, after removing the reverse drag signal in the rotational speed signal in the target duty cycle, and before performing Fourier transform on the rotational speed signal after removing the reverse drag, according to the rotational speed in the target duty cycle Signal to determine the average speed of the engine in the target working cycle; obtain the average speed of the engine in the last working cycle of the target working cycle; according to the average speed of the engine in the target working cycle, the average speed of the previous working cycle, and The number of teeth of the test ring gear of the engine is determined to determine the trend item to be eliminated; the trend item in the rotational speed signal after the reverse drag is eliminated, and the rotational speed signal after the de-trend item is obtained;
  • the processing unit 602 is specifically configured to perform Fourier transform on the rotational speed signal after the detrending term.
  • the engine misfire detection device provided in this embodiment is the same as the technical solution in implementing the engine misfire detection method provided in any of the foregoing embodiments, and its implementation principles and technical effects are similar, and will not be repeated.
  • Fig. 7 is a schematic structural diagram of an engine misfire detection device provided in the fifth embodiment of the application. As shown in Fig. 7, a memory 701 and a processor 702; among them, the memory 701 is used to store a computer program.
  • the processor 702 executes the computer program in the memory 701 to implement the technical solution of the engine misfire detection method in any implementation manner provided in the foregoing embodiments.
  • the computer-readable storage medium stores computer-executable instructions.
  • the computer-executable instructions are executed by a processor, they are used to implement the method for detecting misfire of an engine in any implementation manner provided by the foregoing embodiments.
  • the present application provides a computer program, including program code.
  • the program code executes the technical solution of the engine misfire detection method in any implementation manner provided in the foregoing embodiments.

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Abstract

一种发动机的失火检测方法包括：获取所述发动机在目标工作循环内的转速信号，并对所述目标工作循环内的转速信号进行频谱分析处理，得到与所述目标工作循环内的转速信号相对应的多阶谐波分量的幅值；根据所述多阶谐波分量的幅值，对所述发动机进行失火检测。该方法易于实现对发动机进行失火检测，进而可极大避免器件损坏。还提供了用于发动机失火检测的装置、设备、存储介质和程序。

Description

发动机的失火检测方法、装置、设备、存储介质和程序 技术领域
本申请涉及交通技术领域，尤其涉及一种发动机的失火检测方法、装置、设备、存储介质和程序。
背景技术
随着社会的不断发展，车辆已成为用户出行的主要代步工具。近年来，车辆中通常设置有直列式的发动机，例如，直列式6缸发动机、直列式8缸发动机等等。
现有技术中，发动机在运行时，发动机的气缸中的混合气可能未点燃，而该现象称为失火现象。
然而现有技术中，当发动机发生失火时，未燃的混合气将会进入到车辆中的三效催化器中，并在三效催化器中燃烧，但是长时间将会造成三效催化器温度过高而被损坏。可见，如何及早实现对发动机进行失火检测已成为当今亟需解决的问题。
发明内容
本申请提供一种发动机的失火检测方法、装置、设备、存储介质和程序，易于实现对发动机进行失火检测，进而可极大避免器件损坏。
第一方面，本申请提供一种发动机的失火检测方法，包括：
获取所述发动机在目标工作循环内的转速信号，并对所述目标工作循环内的转速信号进行频谱分析处理，得到与所述目标工作循环内的转速信号相对应的多阶谐波分量的幅值；
根据所述多阶谐波分量的幅值，对所述发动机进行失火检测。
进一步地，对所述目标工作循环内的转速信号进行频谱分析处理，得到与所述目标工作循环内的转速信号相对应的多阶谐波分量的幅值，包括：
对所述目标工作循环内的转速信号进行傅里叶变换，得到与所述目标工作循环内的转速信号相对应的一至M阶谐波分量的幅值，其中，M为所述发 动机具有的气缸数目，M为大于2的正整数。
进一步地，根据所述多阶谐波分量的幅值，对所述发动机进行失火检测，包括：
确定一阶谐波分量的幅值与M阶谐波分量的幅值的比值，为第一特征值；
若所述第一特征值大于第一预设阈值，则确定所述发动机发生失火。
进一步地，所述方法还包括：
若所述第一特征值小于等于所述第一预设阈值，则根据二阶谐波分量的幅值与K阶谐波分量的幅值，确定第二特征值，其中，K的取值为大于1且小于M的所有奇数；
若所述第二特征值大于第二预设阈值，则确定所述发动机发生对称缸失火；若所述第二特征值小于等于所述第二预设阈值，则确定所述发动机未发生失火。
进一步地，当M＝6时，所述第二特征值为，(二阶谐波分量的幅值+四阶谐波分量的幅值)/[(三阶谐波分量的幅值+五阶谐波分量的幅值+a)-六阶谐波分量的幅值/(二阶谐波分量的幅值+四阶谐波分量的幅值+b)]，其中，a为预设第一数值，b为预设第二数值。
进一步地，在所述确定所述发动机发生失火之后，还包括：
确定1/(2/M)阶谐波分量的幅值与R阶谐波分量的幅值的比值，为第三特征值，其中，R为大于1且小于M的正整数，且当M＝6时，R＝2；
若第三特征值大于第三预设阈值，则确定所述发动机发生间隔缸失火。
进一步地，所述方法还包括：
若所述第三特征值小于等于所述第三预设阈值，则确定第四特征值，其中，所述第四特征值为，一阶谐波分量的幅值/[1/(2/M)阶谐波分量的幅值+c)]，或者，一阶谐波分量的幅值/(M阶谐波分量的幅值+c)，其中，c为预设第三数值；
若所述第四特征值大于第四预设阈值，则确定所述发动机发生相邻缸失火；若所述第四特征值小于等于所述第四预设阈值，则确定所述发动机发生单缸失火。
进一步地，在对所述目标工作循环内的转速信号进行傅里叶变换之前，所述方法还包括：
去除所述目标工作循内的转速信号中的倒拖信号，得到去倒拖后的转速 信号；
所述对所述目标工作循环内的转速信号进行傅里叶变换，包括：
对所述去倒拖后的转速信号进行傅里叶变换。
进一步地，在去除所述目标工作循内的转速信号中的倒拖信号之后，且在对所述去倒拖后的转速信号进行傅里叶变换之前，还包括：
根据所述目标工作循环内的转速信号，确定所述发动机在所述目标工作循环内的平均转速；
获取所述发动机在所述目标工作循环的上一个工作循环内的平均转速；
根据所述发动机在所述目标工作循环内的平均转速、所述上一个工作循环内的平均转速，以及所述发动机的测试齿圈的齿数，确定待剔除的趋势项；
剔除所述去倒拖后的转速信号中的趋势项，得到去趋势项后的转速信号；
所述对所述去倒拖后的转速信号进行傅里叶变换，包括：
对所述去趋势项后的转速信号进行傅里叶变换。
第二方面，本申请提供一种发动机的失火检测装置，包括：
获取单元，用于获取所述发动机在目标工作循环内的转速信号；
处理单元，用于并对所述目标工作循环内的转速信号进行频谱分析处理，得到与所述目标工作循环内的转速信号相对应的多阶谐波分量的幅值；
检测单元，用于根据所述多阶谐波分量的幅值，对所述发动机进行失火检测。
进一步地，所述处理单元，具体用于对所述目标工作循环内的转速信号进行傅里叶变换，得到与所述目标工作循环内的转速信号相对应的一至M阶谐波分量的幅值，其中，M为所述发动机具有的气缸数目，M为大于2的正整数。
进一步地，所述检测单元，具体用于确定一阶谐波分量的幅值与M阶谐波分量的幅值的比值，为第一特征值；若所述第一特征值大于第一预设阈值，则确定所述发动机发生失火。
进一步地，所述检测单元，还用于若所述第一特征值小于等于所述第一预设阈值，则根据二阶谐波分量的幅值与K阶谐波分量的幅值，确定第二特征值，其中，K的取值为大于1且小于M的所有奇数；若所述第二特征值大于第二预设阈值，则确定所述发动机发生对称缸失火；若所述第二特征值小于等于所述第二预设阈值，则确定所述发动机未发生失火。
进一步地，当M＝6时，所述第二特征值为，(二阶谐波分量的幅值+四阶谐波分量的幅值)/[(三阶谐波分量的幅值+五阶谐波分量的幅值+a)-六阶谐波分量的幅值/(二阶谐波分量的幅值+四阶谐波分量的幅值+b)]，其中，a为预设第一数值，b为预设第二数值。
进一步地，所述检测单元，还用于在所述确定所述发动机发生失火之后，确定1/(2/M)阶谐波分量的幅值与R阶谐波分量的幅值的比值，为第三特征值，其中，R为大于1且小于M的正整数，且当M＝6时，R＝2；若第三特征值大于第三预设阈值，则确定所述发动机发生间隔缸失火。
进一步地，所述检测单元，还用于在所述第三特征值小于等于所述第三预设阈值时，则确定第四特征值，其中，所述第四特征值为，一阶谐波分量的幅值/[1/(2/M)阶谐波分量的幅值+c)]，或者，一阶谐波分量的幅值/(M阶谐波分量的幅值+c)，其中，c为预设第三数值；若所述第四特征值大于第四预设阈值，则确定所述发动机发生相邻缸失火；若所述第四特征值小于等于所述第四预设阈值，则确定所述发动机发生单缸失火。
进一步地，所述处理单元，还用于在对所述目标工作循环内的转速信号进行傅里叶变换之前，去除所述目标工作循内的转速信号中的倒拖信号，得到去倒拖后的转速信号；
所述处理单元，具体用于对所述去倒拖后的转速信号进行傅里叶变换。
进一步地，所述处理单元，还用于在去除所述目标工作循内的转速信号中的倒拖信号之后，且在对所述去倒拖后的转速信号进行傅里叶变换之前，根据所述目标工作循环内的转速信号，确定所述发动机在所述目标工作循环内的平均转速；获取所述发动机在所述目标工作循环的上一个工作循环内的平均转速；根据所述发动机在所述目标工作循环内的平均转速、所述上一个工作循环内的平均转速，以及所述发动机的测试齿圈的齿数，确定待剔除的趋势项；剔除所述去倒拖后的转速信号中的趋势项，得到去趋势项后的转速信号；
所述处理单元，具体用于对所述去趋势项后的转速信号进行傅里叶变换。
第三方面，本申请提供一种发动机的失火检测设备，包括：存储器和处理器；
所述存储器，用于存储计算机程序；
其中，所述处理器执行所述存储器中的计算机程序，以实现第一方面 的任一方法。
第四方面，本申请提供一种计算机可读存储介质，所述计算机可读存储介质中存储有计算机执行指令，所述计算机执行指令被处理器执行时用于实现第一方面的任一方法。
第五方面，本申请提供一种计算机程序，包括程序代码，当计算机运行所述计算机程序时，所述程序代码执行如实现第一方面的任一方法。
本申请提供的发动机的失火检测方法、装置、设备、存储介质和程序，通过获取发动机在目标工作循环内的转速信号，然后对转速信号进行频谱分析处理，以得到多阶谐波分量的幅值，进而可根据所得到的多阶谐波分量的幅值，检测发动机是否失火，进而可及时进行相关维护措施，尽量避免三效催化器的损坏。
附图说明
此处的附图被并入说明书中并构成本说明书的一部分，示出了符合本公开的实施例，并与说明书一起用于解释本公开的原理。
图1为现有技术提供的一种车辆的结构示意图；
图2为本申请实施例一提供的发动机的失火检测方法的流程示意图；
图3为本申请实施例二提供的发动机的失火检测方法的流程示意图；
图4为本申请实施例三提供的发动机的失火检测方法的流程示意图；
图5为本申请实施例三提供的发动机的失火检测结果的示意图；
图6为本申请实施例四提供的发动机的失火检测装置的结构示意图；
图7为本申请实施例五提供的发动机的失火检测设备的结构示意图。
通过上述附图，已示出本公开明确的实施例，后文中将有更详细的描述。这些附图和文字描述并不是为了通过任何方式限制本公开构思的范围，而是通过参考特定实施例为本领域技术人员说明本公开的概念。
具体实施方式
这里将详细地对示例性实施例进行说明，其示例表示在附图中。下面的描述涉及附图时，除非另有表示，不同附图中的相同数字表示相同或相似的要素。以下示例性实施例中所描述的实施方式并不代表与本公开相一致的所有实施方式。相反，它们仅是与如所附权利要求书中所详述的、本 公开的一些方面相一致的装置和方法的例子。
目前，当发动机发生失火时，未燃的混合气进入三效催化器中，并在三效催化器中燃烧，而长时间燃烧将导致三效催化器因为温度过高而损坏，而且，还可能会造成有害气体的排放，污染大气。因而，亟需一种发动机的失火检测方法。
基于此，本申请提供一种发动机的失火检测方法、装置、设备、存储介质和程序，通过获取发动机在一个工作循环内的转速信号，并对转速信号进行频谱分析处理，从而通过频谱分析处理后得到的多阶谐波分量的幅值对发动机进行失火检测，以在检测到发动机失火时，可提醒驾驶人员采取必要的维护措施，避免器件的损坏，减少有毒气体的排放。
另外，本申请的应用场景很多，例如应用在车辆上，该车辆上设置有发动机，其中，发动机可为直列式发动机，示例性的，为直列式6缸发动机。如图1所示，图1为现有技术提供的一种车辆的结构示意图，本申请可应用在图1所示的车辆上。
下面将对本申请提供的发动机的失火检测方法、装置、设备、存储介质和程序，进行详细说明。
图2为本申请实施例一提供的发动机的失火检测方法的流程示意图，如图2所示，该方法包括：
步骤201：获取发动机在目标工作循环内的转速信号。
实际应用中，本实施例的执行主体可以为发动机的失火检测装置，该发动机的失火检测装置可以为程序软件，也可以为存储有相关计算机程序的介质，例如，U盘等；或者，该发动机的失火检测装置还可以为集成或安装有相关计算机程序的实体设备，例如，芯片、智能终端、电脑、服务器等。另外，该装置可以设置在车辆中，以对同样安装在该车辆上的发动机进行失火检测。
在本实施例中，发动机每完成一个工作循环，可将刚完成的该工作循环作为目标工作循环，并获取发动机在该目标工作循环内的转速信号。以四冲程的发动机举例来说，一个工作循环包括进气冲程、压缩冲程、做功冲程和排气冲程。或者，发动机上的曲轴每转两圈，即720度，为一个工作循环。另外，发动机在一个工作循环内的转速信号可包括多个瞬时转速 信号，其中，发动机的瞬时转速信号可通过安装在飞轮端的测速齿圈进行测定。
步骤202：对目标工作循环内的转速信号进行频谱分析处理，得到与目标工作循环内的转速信号相对应的多阶谐波分量的幅值。
在本实施例中，在获取到发动机在目标工作循环内的转速信号后，便可对该目标工作循环内的转速信号(即所包括的多个瞬时转速信号)，进行频谱分析处理，示例性的，可对目标工作循环内的转速信号进行快速傅里叶变换(Fast Fourier Transform，简称FFT)，从而可得到多阶谐波分量的幅值。举例来说，多阶谐波分量的幅值可包括一阶谐波分量的幅值、二阶谐波分量的幅值…Q阶谐波分量的幅值等多个幅值，其中，Q为大于1的正整数，Q的值可根据实际需求进行设定。
步骤203：根据多阶谐波分量的幅值，对发动机进行失火检测。
在本实施例中，在得到多阶谐波分量的幅值之后，便可根据多阶谐波分量的幅值，检测发动机是否发生失火，以及在检测到发动机发生失火时，具体的失火形式。
本申请提供一种发动机的失火检测方法，通过获取发动机在目标工作循环内的转速信号，然后对转速信号进行频谱分析处理，以得到多阶谐波分量的幅值，进而可根据所得到的多阶谐波分量的幅值，检测发动机是否失火，进而可及时进行相关维护措施，尽量避免三效催化器的损坏。
图3为本申请实施例二提供的发动机的失火检测方法的流程示意图，如图3所示，该方法包括：
步骤301：获取发动机在目标工作循环内的转速信号。
在本实施例中，有关工作循环的具体解释可参照实施例一中的步骤201，此处不再赘述。
具体的，目标工作循环内的转速信号可包括多个瞬时转速信号，其中，可通过如下公式(1)计算发动机的瞬时转速信号。
S RPM＝60/(N toothΔt)     (1)
其中，S RPM为发动机的瞬时转速信号，N tooth为发动机的测速齿圈的齿数，Δt为齿周期。通常情况下，测试齿圈的齿数N tooth应不小于60，Δt的有效数字位数应不小于4位。
基于此，示例性的，以四冲程的发动机为例，可获取到发动机在目标工作循环i内的转速信号
Figure PCTCN2020082391-appb-000001
其中，共包括2N tooth个瞬时转速信号。
实际应用中，还可根据实际需求，设置触发执行301的失火诊断程序释放条件，那么，当满足该条件时，才执行步骤301。举例来说，当确定发动机所在车辆未处于上坡，或者下坡的场景时，触发执行步骤301。上述仅是举例说明，并不对本发明进行限制。
步骤302：去除目标工作循内的转速信号中的倒拖信号，得到去倒拖后的转速信号。
实际应用中，通过发动机的气缸中的气体做功，会使得发动机产生转速信号。另外，活塞的摩擦，或者是发动机的惯性原件、连杆等也会产生一部分转速信号，其该部分转速信号即为倒拖信号。倒拖信号相当于其转速信号的背景噪声，对检测发动机是否失火具有明显干扰作用，因而，应将转速信号中的倒拖信号去除，以提高对发动机失火检测的准确性。
以上述目标工作循环内的转速信号包括2N tooth个瞬时转速信号为例，应对每个瞬速转速信号进行去倒拖信号处理。具体的，可通过在各个转速下测定幅值与相位的方法对其进行标定，基于此，去除倒拖信号。除此之外，还可通过其他现有技术进行去除，此处不再展开说明。
步骤303：根据目标工作循环内的转速信号，确定发动机在目标工作循环内的平均转速，并获取发动机在目标工作循环的上一个工作循环内的平均转速，根据发动机在目标工作循环内的平均转速、上一个工作循环内的平均转速，以及发动机的测试齿圈的齿数，确定待剔除的趋势项，并剔除去倒拖后的转速信号中的趋势项，得到去趋势项后的转速信号。
实际应用中，发动机在加减速的过程中，其转速信号并不平稳，从而也会给失火检测造成干扰，因而应当剔除发动机的速度趋势变化分量，即待剔除的趋势项。具体的，可通过如下公式(2)计算待剔除的趋势项。
Figure PCTCN2020082391-appb-000002
其中，S trend为待剔除的趋势项，
Figure PCTCN2020082391-appb-000003
为发动机在目标工作循环内的平均转速，
Figure PCTCN2020082391-appb-000004
为发动机在目标工作循环的上一个工作循环内的平均转速，[1,2,…,2N tooth]是一个向量。
基于此，剔除趋势项后的转速信号为
Figure PCTCN2020082391-appb-000005
步骤304：对去趋势项后的转速信号进行傅里叶变换，得到与目标工作循环内的转速信号相对应的一至M阶谐波分量的幅值，其中，M为发动机具有的气缸数目，M为大于2的正整数。
在本实施例中，在得到剔除趋势项后的转速信号为
Figure PCTCN2020082391-appb-000006
后，对包含有2N tooth个处理后的瞬时转速信号的
Figure PCTCN2020082391-appb-000007
进行傅里叶变换，具体的，可进行快速傅里叶变换，从而可得到一至M阶谐波分量的幅值。举例来说，当发动机为直列式6缸发动机时，则可提取一至六阶谐波分量的幅值；当发动机为直列式8缸发动机时，则可提取一至八阶谐波分量的幅值。
步骤305：根据一至M阶谐波分量的幅值，对发动机进行失火检测。
在本实施例中，在获取到一至M阶谐波分量的幅值后，便可基于此检测发动机是否发生失火，以及在发生失火时，具体的失火形式。下面将通过实施例三详细说明失火检测的过程。
本实施例在获取到发动机在目标工作循环内的转速信号后，通过对转速信号进行去倒拖信号处理，从而减少了倒拖信号对失火检测所造成的干扰，提高了失火检测的准确性。基于此，在得到去倒拖后的转速信号后，通过剔除其中的趋势项，减少发动机在加减速时，发动机对于失火检测所带来的干扰，基于剔除趋势项后的转速信号，可进一步提升失火检测准确性。
图4为本申请实施例三提供的发动机的失火检测方法的流程示意图，如图4所示，该方法包括：
步骤401：确定一阶谐波分量的幅值与M阶谐波分量的幅值的比值，为第一特征值，其中，M为发动机具有的气缸数目，M为大于2的正整数。
示例性的，当发动机为直列式4缸发动机时，M＝4，则第一特征值＝一阶谐波分量的幅值/四阶谐波分量的幅值；当发动机为直列式6缸发动机时，M＝6，则第一特征值＝一阶谐波分量的幅值/六阶谐波分量的幅值；当发动机为直列式8缸发动机时，M＝8，则第一特征值＝一阶谐波分量的幅值/八阶谐波分量的幅值。
步骤402：判断第一特征值是否大于第一预设阈值，若否，则执行步骤403，若是，则确定发动机发生失火，并执行步骤407。
在本实施例中，预先可通过进行失火实验，标定第一预设阈值。可选的，第一预设阈值可为0.3。基于此，在确定出第一特征值之后，便可将其与第一 预设阈值进行比较，若第一特征值小于第一预设阈值，则说明发动机发生了失火，其失火形式可能是单缸失火、间隔缸失火、或者相邻缸失火；若第一特征值小于等于第一预设阈值，还需进一步验证是否发生对称缸失火。
图5为本申请实施例三提供的发动机的失火检测结果的示意图，如图5所示，该图的右侧纵坐标为发动机的转速信号，左侧纵坐标为第一特征值，横坐标为时间。具体的，可获取发动机在连续的多个工作循环内的转速信号，然后根据发动机在这些工作循环内的转速信号，形成图5中的转速曲线，示例性的，每个工作循环可对应120个转速信号，即一个工作循环内的转速曲线由该工作循环内的120个转速信号形成。针对每个工作循环，可根据步骤401中的计算方式，计算每个工作循环所对应的第一特征值，即120个转速信号对应一个第一特征值，示例性的，可在每个工作循环所对应的最后一个转速信号所对应的时间点绘制相应的第一特征值，进而得到图5中的第一特征值所对应的曲线。从而在得到图5之后，直观的向用户展示发动机的失火检测结果。而且，用户可根据图5和第一预设阈值，确定发动机是否发生单缸失火、间隔缸失火、或者相邻缸失火中的任一种失火。
步骤403：根据二阶谐波分量的幅值与K阶谐波分量的幅值，确定第二特征值，其中，K的取值为大于1且小于M的所有奇数。
示例性的，当发动机为直列式4缸发动机时，M＝4，则K的取值只有3，则根据其二阶谐波分量的幅值以及三阶谐波分量的幅值确定第二特征值；当发动机为直列式6缸发动机时，M＝6，则K的取值有3和5，则根据其二阶谐波分量的幅值、三阶谐波分量的幅值和五阶谐波分量的幅值确定第二特征值；当发动机为直列式8缸发动机时，M＝8，则K的取值有3、5、7，则根据其二阶谐波分量的幅值、三阶谐波分量的幅值、五阶谐波分量的幅值和七阶谐波分量的幅值确定第二特征值。
具体的，当发动机为直列式4缸发动机，即M＝4时，第二特征值为，(二阶谐波分量的幅值)/[(三阶谐波分量的幅值+a)]，其中，a为预设第一数值a可取值为0.1。
具体的，当发动机为直列式6缸发动机，即M＝6时，第二特征值为，(二阶谐波分量的幅值+四阶谐波分量的幅值)/[(三阶谐波分量的幅值+五阶谐波分量的幅值+a)-六阶谐波分量的幅值/(二阶谐波分量的幅值+四阶谐波分量的幅值+b)]，其中，a为预设第一数值，b为预设第二数值。可选的，a、b可取值 为0.1。
具体的，当发动机为直列式8缸发动机，即M＝8时，第二特征值为，(二阶谐波分量的幅值)/[(三阶谐波分量的幅值+五阶谐波分量的幅值+七阶谐波分量的幅值+a)]，其中，a为预设第一数值a可取值为0.1。
步骤404：判断第二特征值是否大于第二预设阈值，若是，则执行步骤405，若否，则执行步骤406。
在本实施例中，同样会预先标定第二预设阈值。可选的，第二预设阈值可为0.4。基于此，在确定出第二特征值之后，便可将其与第二预设阈值进行比较，若第二特征值大于第二预设阈值，则说明发动机发生对称缸失火；若第二特征值小于等于第二预设阈值，则说明发动机未发生失火。
另外，为直观的向用户展示对称缸的失火检测结果，还可参照图5，形成转速曲线与第二特征值所对应的曲线，或者是，在图5的基础上，形成第二特征值所对应的曲线(即包括转速曲线、第一特征值所对应的曲线和第二特征值所对应的曲线)，此处不再过多赘述。
步骤405：确定发动机发生对称缸失火。
在本实施例中，当发动机发生对称缸失火时，其一阶谐波分量会被二阶谐波分量所掩盖，因此需要附加一次判定其是否属于对称缸失火。
步骤406：确定发动机未发生失火。
在本实施例中，通过所确定的第一特征值和第二特征值，能够发动机是否发生失火进行准确判定，而且不易出现误判。
步骤407：确定1/(2/M)阶谐波分量的幅值与R阶谐波分量的幅值的比值，为第三特征值，其中，R为大于1且小于M的正整数，且当M＝6时，R＝2。
示例性的，当发动机为直列式4缸发动机时，即M＝4，则1/(2/4)＝2，可选的，可根据其二阶谐波分量的幅值，与R(可取R＝M＝4)阶谐波分量的幅值，确定第三特征值；当发动机为直列式6缸发动机时，M＝6，则1/(2/6)＝3，可选的，可根据其三阶谐波分量的幅值，与R(可取R＝2)阶谐波分量的幅值，确定其第三特征值；当发动机为直列式8缸发动机时，M＝8，则1/(2/8)＝4，可选的，可根据其四阶谐波分量的幅值，与R(可取R＝M＝8)阶谐波分量的幅值，确定其第三特征值。
步骤408：判断第三特征值是否大于第三预设阈值，若是，则执行步骤409，若否，则执行步骤410。
在本实施例中，同样会预先标定第三预设阈值。基于此，在确定出第三特征值之后，便可将其与第三预设阈值进行比较，若第三特征值大于第三预设阈值，则说明发动机发生间隔缸失火；若第三特征值小于等于第三预设阈值，则还需判定发动机是否发生相邻缸失火。
另外，为直观的向用户展示间隔缸的失火检测结果，还可参照图5，形成转速曲线与第三特征值所对应的曲线，此处不再过多赘述。
步骤409：确定发动机发生间隔缸失火。
在本实施例中，基于所确定的第三特征值，能够准确判断发动机是否发生间隔缸失火。
步骤410：确定第四特征值，其中，第四特征值为，一阶谐波分量的幅值/[1/(2/M)阶谐波分量的幅值+c)]，或者，一阶谐波分量的幅值/(M阶谐波分量的幅值+c)，其中，c为预设第三数值。
在本实施例中，针对直列式4缸发动机，由于其在发生相邻缸失火时，发动机直接不在运转，因而无需在进行步骤410至411。示例性的，当发动机为直列式6缸发动机时，M＝6，则1/(2/6)＝3，可选的，可根据其一阶谐波分量的幅值，与三阶谐波分量的幅值，确定其第四特征值；当发动机为直列式8缸发动机时，M＝8，则1/(2/8)＝4，可选的，可根据其一阶谐波分量的幅值，与四阶谐波分量的幅值，确定其第四特征值，或者是，根据其一阶谐波分量的幅值，与八阶谐波分量的幅值，确定其第四特征值。其中，c可取值为0.1。
步骤411：判断第四特征值是否大于第四预设阈值，若是，则执行步骤412，若否，则执行步骤413。
在本实施例中，同样会预先标定第四预设阈值。基于此，在确定出第四特征值之后，便可将其与第四预设阈值进行比较，若第四特征值大于第四预设阈值，则说明发动机发生相邻缸失火；若第四特征值小于等于第四预设阈值，则还需判定发动机发生单缸失火。
另外，为直观的向用户展示相邻缸的失火检测结果，还可参照图5，形成转速曲线与第四特征值所对应的曲线，此处不再过多赘述。
步骤412：确定发动机发生相邻缸失火。
步骤413：确定发动机发生单缸失火。
在本实施例中，在对发动机进行失火检测后，还可基于检测的结果计算失火比率。具体的，可通过如下公式(3)计算失火比率。
Figure PCTCN2020082391-appb-000008
其中，λ misfire为失火比率，∑I single为发动机发生单缸失火的工作循环总数，∑I double为发动机发生对称缸、间隔缸、相邻缸失火的工作循环总数，I total为总工作循环数。
在本实施例中，在得到失火比率后，便可根据设定的不同阈值，判断车辆是处于排放损害型失火或催化器损坏型失火，以便提醒驾驶员，并采取相应补救措施。
另外，在本实施例中，为了进一步提升对发动机的失火检测准确性，还可标定不同平均转速区间下的第一预设阈值、第二预设阈值、第三预设阈值和第四预设阈值。以直列式6缸发动机为例，针对其预先标定有平均转速区间1与第一预设阈值A对应，平均转速区间2与第一预设阈值B对应，平均转速区间3与第一预设阈值C对应。假设在获取到该直列式6缸发动机在目标工作循环内的转速信号后，可确定该目标工作循环内的平均转速，若所确定的平均转速位于平均转速区间2内，则在进行失火检测时，则是将第一特征值与第一预设阈值A进行比较。而针对其他各预设阈值，可参照上述第一预设阈值的解释，此处不再过多解释。
本实施基于一阶谐波分量的幅值和M阶谐波分量的幅值所确定的第一特征值，可用于确定出是否发生间隔缸失火、对称缸失火或者是单缸失火中，如果否，则由于当发动机发生对称缸失火时，其一阶谐波分量会被二阶谐波分量所掩盖，因此基于二阶谐波分量，附加一次判定其是否属于对称缸失火。如果是，则基于所确定的第三特征值，能够准确判断发动机是否发生间隔缸失火。并在确定不是间隔缸失火时，在基于一阶谐波分量的幅值，准确判断发动机是否发生相邻缸失火。
本发明适用于发动机高转速、低载荷的工作条件下，能够准确报出失火故障。而且，本发明中所提出的方法具有判定阈值易标定的特性，无需基于发动机在不同工作模式、负载、离合器类型、变速箱型号、路况下的失火判定阈值，以及根据其他附件的工作条件对阈值进行附加修正的工作，容易完成对第一至第四预设阈值的标定工作，而且，这些预设阈值对负载变化和转速变化不敏感，在较宽广的转速、负载变化范围内皆可采用同一阈值，大大 减少了车载诊断***(On-Board Diagnostic，简称OBD)标定工作量和发动机控制器的内存占用空间。另外，本发明所提出的方法对发动机加减速变化不敏感，即使当发动机在极加速的过程中，本发明所提出的算法仍未产生失火故障误报，因此该方法能够适用于车速不稳定的工况。再者，本发明所提出的方法具有自适应特性，即，当发动机出现性能衰退时，由于本发明所提出的方法不依赖于计算发动机缸内平均有效压力的绝对值的变化量，因此对发动机的性能衰退适应性较强，能够在发动机出现明显的性能劣化后保持准确性。除此之外，本发明所提出的方法能够在高速时诊断相邻缸、间隔缸失火，当发动机在高转速发生相邻缸、间隔缸失火时，即使曲轴扭振，本发明所提出的方法在发动机高转速时仍能够准确识别出发动机的间隔缸失火和相邻缸失火，且不漏报、不误报。
图6为本申请实施例四提供的发动机的失火检测装置的结构示意图，如图6所示，该装置包括：获取单元601、处理单元602和检测单元603。其中，
获取单元601，用于获取发动机在目标工作循环内的转速信号；
处理单元602，用于并对目标工作循环内的转速信号进行频谱分析处理，得到与目标工作循环内的转速信号相对应的多阶谐波分量的幅值；
检测单元603，用于根据多阶谐波分量的幅值，对发动机进行失火检测。
进一步地，处理单元602，具体用于对目标工作循环内的转速信号进行傅里叶变换，得到与目标工作循环内的转速信号相对应的一至M阶谐波分量的幅值，其中，M为发动机具有的气缸数目，M为大于2的正整数。
进一步地，检测单元603，具体用于确定一阶谐波分量的幅值与M阶谐波分量的幅值的比值，为第一特征值；若第一特征值大于第一预设阈值，则确定发动机发生失火。
进一步地，检测单元603，还用于若第一特征值小于等于第一预设阈值，则根据二阶谐波分量的幅值与K阶谐波分量的幅值，确定第二特征值，其中，K的取值为大于1且小于M的所有奇数；若第二特征值大于第二预设阈值，则确定发动机发生对称缸失火；若第二特征值小于等于第二预设阈值，则确定发动机未发生失火。
进一步地，当M＝6时，第二特征值为，(二阶谐波分量的幅值+四阶谐波分量的幅值)/[(三阶谐波分量的幅值+五阶谐波分量的幅值+a)-六阶谐波分量 的幅值/(二阶谐波分量的幅值+四阶谐波分量的幅值+b)]，其中，a为预设第一数值，b为预设第二数值。
进一步地，检测单元603，还用于在确定发动机发生失火之后，确定1/(2/M)阶谐波分量的幅值与R阶谐波分量的幅值的比值，为第三特征值，其中，R为大于1且小于M的正整数，且当M＝6时，R＝2；若第三特征值大于第三预设阈值，则确定发动机发生间隔缸失火。
进一步地，检测单元603，还用于在第三特征值小于等于第三预设阈值时，则确定第四特征值，其中，第四特征值为，一阶谐波分量的幅值/[1/(2/M)阶谐波分量的幅值+c)]，或者，一阶谐波分量的幅值/(M阶谐波分量的幅值+c)，其中，c为预设第三数值；若第四特征值大于第四预设阈值，则确定发动机发生相邻缸失火；若第四特征值小于等于第四预设阈值，则确定发动机发生单缸失火。
进一步地，处理单元602，还用于在对目标工作循环内的转速信号进行傅里叶变换之前，去除目标工作循内的转速信号中的倒拖信号，得到去倒拖后的转速信号；
处理单元602，具体用于对去倒拖后的转速信号进行傅里叶变换。
进一步地，处理单元602，还用于在去除目标工作循内的转速信号中的倒拖信号之后，且在对去倒拖后的转速信号进行傅里叶变换之前，根据目标工作循环内的转速信号，确定发动机在目标工作循环内的平均转速；获取发动机在目标工作循环的上一个工作循环内的平均转速；根据发动机在目标工作循环内的平均转速、上一个工作循环内的平均转速，以及发动机的测试齿圈的齿数，确定待剔除的趋势项；剔除去倒拖后的转速信号中的趋势项，得到去趋势项后的转速信号；
处理单元602，具体用于对去趋势项后的转速信号进行傅里叶变换。
本实施例提供的发动机的失火检测装置，同于实现前述任一实施例提供的发动机的失火检测方法中的技术方案，其实现原理和技术效果类似，不再赘述。
图7为本申请实施例五提供的发动机的失火检测设备的结构示意图，如图7所示，存储器701和处理器702；其中，存储器701，用于存储计算机程序。
其中，处理器702执行存储器701中的计算机程序，以实现前述实施例提供的任一实现方式的发动机的失火检测方法的技术方案。
本申请提供一种计算机可读存储介质，计算机可读存储介质中存储有计算机执行指令，计算机执行指令被处理器执行时用于实现前述实施例提供的任一实现方式的发动机的失火检测方法的技术方案。
本申请提供一种计算机程序，包括程序代码，当计算机运行所述计算机程序时，所述程序代码执行前述实施例提供的任一实现方式的发动机的失火检测方法的技术方案。
本领域技术人员在考虑说明书及实践这里公开的发明后，将容易想到本公开的其它实施方案。本申请旨在涵盖本公开的任何变型、用途或者适应性变化，这些变型、用途或者适应性变化遵循本公开的一般性原理并包括本公开未公开的本技术领域中的公知常识或惯用技术手段。说明书和实施例仅被视为示例性的，本公开的真正范围和精神由下面的权利要求书指出。
以上所述，仅为本发明的具体实施方式，但本发明的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本发明揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本发明的保护范围之内。因此，本发明的保护范围应以所述权利要求的保护范围为准。

Claims (13)

  1. 一种发动机的失火检测方法，其特征在于，所述方法，包括：
    获取所述发动机在目标工作循环内的转速信号，并对所述目标工作循环内的转速信号进行频谱分析处理，得到与所述目标工作循环内的转速信号相对应的多阶谐波分量的幅值；
    根据所述多阶谐波分量的幅值，对所述发动机进行失火检测。
  2. 根据权利要求1所述的方法，其特征在于，对所述目标工作循环内的转速信号进行频谱分析处理，得到与所述目标工作循环内的转速信号相对应的多阶谐波分量的幅值，包括：
    对所述目标工作循环内的转速信号进行傅里叶变换，得到与所述目标工作循环内的转速信号相对应的一至M阶谐波分量的幅值，其中，M为所述发动机具有的气缸数目，M为大于2的正整数。
  3. 根据权利要求2所述的方法，其特征在于，根据所述多阶谐波分量的幅值，对所述发动机进行失火检测，包括：
    确定一阶谐波分量的幅值与M阶谐波分量的幅值的比值，为第一特征值；
    若所述第一特征值大于第一预设阈值，则确定所述发动机发生失火。
  4. 根据权利要求3所述的方法，其特征在于，所述方法还包括：
    若所述第一特征值小于等于所述第一预设阈值，则根据二阶谐波分量的幅值与K阶谐波分量的幅值，确定第二特征值，其中，K的取值为大于1且小于M的所有奇数；
    若所述第二特征值大于第二预设阈值，则确定所述发动机发生对称缸失火；若所述第二特征值小于等于所述第二预设阈值，则确定所述发动机未发生失火。
  5. 根据权利要求4所述的方法，其特征在于，当M＝6时，所述第二特征值为，(二阶谐波分量的幅值+四阶谐波分量的幅值)/[(三阶谐波分量的幅值+五阶谐波分量的幅值+a)-六阶谐波分量的幅值/(二阶谐波分量的幅值+四阶谐波分量的幅值+b)]，其中，a为预设第一数值，b为预设第二数值。
  6. 根据权利要求3-5任一项所述的方法，其特征在于，在所述确定所述发动机发生失火之后，还包括：
    确定1/(2/M)阶谐波分量的幅值与R阶谐波分量的幅值的比值，为第三特 征值，其中，R为大于1且小于M的正整数，且当M＝6时，R＝2；
    若第三特征值大于第三预设阈值，则确定所述发动机发生间隔缸失火。
  7. 根据权利要求6所述的方法，其特征在于，所述方法还包括：
    若所述第三特征值小于等于所述第三预设阈值，则确定第四特征值，其中，所述第四特征值为，一阶谐波分量的幅值/[1/(2/M)阶谐波分量的幅值+c)]，或者，一阶谐波分量的幅值/(M阶谐波分量的幅值+c)，其中，c为预设第三数值；
    若所述第四特征值大于第四预设阈值，则确定所述发动机发生相邻缸失火；若所述第四特征值小于等于所述第四预设阈值，则确定所述发动机发生单缸失火。
  8. 根据权利要求2-5、7任一项所述的方法，其特征在于，在对所述目标工作循环内的转速信号进行傅里叶变换之前，所述方法还包括：
    去除所述目标工作循内的转速信号中的倒拖信号，得到去倒拖后的转速信号；
    所述对所述目标工作循环内的转速信号进行傅里叶变换，包括：
    对所述去倒拖后的转速信号进行傅里叶变换。
  9. 根据权利要求8所述的方法，其特征在于，在去除所述目标工作循内的转速信号中的倒拖信号之后，且在对所述去倒拖后的转速信号进行傅里叶变换之前，还包括：
    根据所述目标工作循环内的转速信号，确定所述发动机在所述目标工作循环内的平均转速；
    获取所述发动机在所述目标工作循环的上一个工作循环内的平均转速；
    根据所述发动机在所述目标工作循环内的平均转速、所述上一个工作循环内的平均转速，以及所述发动机的测试齿圈的齿数，确定待剔除的趋势项；
    剔除所述去倒拖后的转速信号中的趋势项，得到去趋势项后的转速信号；
    所述对所述去倒拖后的转速信号进行傅里叶变换，包括：
    对所述去趋势项后的转速信号进行傅里叶变换。
  10. 一种发动机的失火检测装置，其特征在于，所述装置，包括：
    获取单元，用于获取所述发动机在目标工作循环内的转速信号；
    处理单元，用于并对所述目标工作循环内的转速信号进行频谱分析处理，得到与所述目标工作循环内的转速信号相对应的多阶谐波分量的幅值；
    检测单元，用于根据所述多阶谐波分量的幅值，对所述发动机进行失火检测。
  11. 一种发动机的失火检测设备，其特征在于，包括存储器和处理器；
    所述存储器，用于存储计算机程序；
    其中，所述处理器执行所述存储器中的计算机程序，以实现如权利要求1-9任一项所述的方法。
  12. 一种计算机可读存储介质，其特征在于，所述计算机可读存储介质中存储有计算机执行指令，所述计算机执行指令被处理器执行时用于实现如权利要求1-9任一项所述的方法。
  13. 一种计算机程序，其特征在于，包括程序代码，当计算机运行所述计算机程序时，所述程序代码执行如权利要求1-9任一项所述的方法。
PCT/CN2020/082391 2020-03-31 2020-03-31 发动机的失火检测方法、装置、设备、存储介质和程序 WO2021195948A1 (zh)

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