Engine combustion noise evaluation method and device

Abstract

The application relates to the technical field of vehicles and discloses an engine combustion noise evaluation method and device. The method comprises the following steps: configuring multiple preselected working condition points under multiple engine load characteristics, and collecting in-cylinder pressure signals in a preset cycle number at each preselected working condition point; after each in-cylinder pressure signal is preprocessed, all the preprocessed signals are integrated to calculate working condition point characteristic values of the multiple preselected working condition points; at least on the basis of the working condition point characteristic values corresponding to each preselected working condition point, a first engine parameter and a second engine parameter, one or more grid data points are generated on a preset parameter plane by using a preset data point generation algorithm, and then a maximum pressure rise rate universal characteristic diagram is drawn; and an engine combustion noise evaluation result is determined according to at least the maximum pressure rise rate universal characteristic diagram. The application can at least shorten the NVH performance development cycle and reduce the development cost.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, and in particular to a method and apparatus for evaluating engine combustion noise. Background Technology

[0002] During engine combustion, the cylinder pressure changes rapidly, and the piston-connecting rod mechanism causes cylinder block vibration, which radiates noise. When the proportion of energy in the mid-to-high frequency range, which is sensitive to the human ear, is high, it can easily cause subjective annoyance. How to construct a universal characteristic diagram to objectively and comprehensively characterize the combustion noise distribution characteristics of the engine under all operating conditions, and thus effectively assess the combustion noise level, is one of the important issues in the current forward development of engines.

[0003] Patent document CN113704879A discloses a visualization correlation analysis method for engine radiated noise and combustion excitation. The main steps include: arranging cylinder pressure measurement points and radiated noise measurement points in a semi-anechoic chamber test bench, conducting constant speed torque increase tests at multiple speed points, and simultaneously acquiring cylinder pressure signals, radiated noise signals, and crankshaft angle signals; performing angle domain resampling and correction processing on the cylinder pressure signals under each speed condition, calculating the curve of the average pressure rise rate of each cylinder as a function of torque, and obtaining the average pressure rise rate matrix CPR; simultaneously calculating the curve of the average radiated noise sound pressure level at four points as a function of torque under different speed conditions, and obtaining the sound pressure level matrix SPL; after establishing a constant speed torque increase database for multiple engines, calculating the pressure rise rate difference matrix ΔCPR and the sound pressure level difference matrix ΔSPL at equal power points, and plotting speed-torque distribution cloud maps respectively, and confirming the strong correlation points between high-frequency combustion excitation and radiated noise through horizontal comparison.

[0004] Problems with this patent document: 1. Lack of universality of universal characteristic diagram: Although the patent document adopts the form of cloud diagram, it is essentially a difference comparison method for benchmarking analysis of two engines, rather than constructing a universal characteristic diagram that can be used independently. 2. The core objective of this patent document is to identify the "strongly correlated operating point" between high-frequency combustion excitation and radiated noise, which has limited guiding value for overall optimization design; 3. Reliance on radiated noise measurement points: This patent document requires the arrangement of radiated noise measurement points and the measurement of sound pressure level signals, which means that the test must be carried out in a semi-anechoic chamber environment. The test environment requirements are harsh and the universality is limited.

[0005] Patent document CN110375989B discloses an engine combustion noise detection system, including a cylinder pressure signal acquisition module and a signal processing module. The signal processing module performs the following steps: Step 1, processing the cylinder pressure signal using the variational mode decomposition (VMD) method to extract different excitation source sub-signals, including combustion excitation signal, combustion resonance excitation signal, drag signal, and high-frequency oscillation signal; Step 2, processing the excitation source sub-signals using fast Fourier transform, converting the spectrum into power spectral density, obtaining the spectrum corresponding to the combustion signal and combustion resonance signal, and performing inverse Fourier transform to obtain the time-domain signal; Step 3, using the envelope derivative energy operator, calculating the combustion signal and combustion resonance signal to obtain the instantaneous combustion noise frequency-weighted energy.

[0006] Problems with this patent document: 1. Complete lack of universal characteristic diagram construction: This patent document focuses on technical improvements at the "detection system" level, aiming to accurately extract combustion noise energy from cylinder pressure signals. The system only provides a single combustion noise energy value at a single operating point, but cannot indicate how the combustion noise is distributed across the entire operating range of the engine; 2. High algorithm complexity, limiting engineering applicability: This patent document employs a series of complex signal processing algorithms such as variational mode decomposition, Fourier transform, and envelope derivative energy operator, which poses a high barrier to practical application.

[0007] Patent document CN112632690A discloses a method and apparatus for determining combustion noise parameters. This patent proposes a new method for determining combustion noise parameters: obtaining an in-cylinder pressure sequence containing different crankshaft rotation angles φ and corresponding times tφ; calculating a first parameter sequence based on the in-cylinder pressure sequence, the first parameter sequence including one or more of the top surface cylinder force sequence, the top surface cylinder force pressure rise rate sequence, the side cylinder force sequence, and the side cylinder force pressure rise rate sequence; and finally determining the target parameters characterizing the in-cylinder combustion noise based on the first parameter sequence.

[0008] Problems with this patent document: 1. No comprehensive visualization analysis method for all operating conditions: This patent document only addresses the issue of "parameter selection", namely, finding more accurate and complete combustion noise characterization parameters, but does not further discuss how to use these parameters to construct a combustion noise distribution view of the engine under all operating conditions. It lacks an intuitive means to observe the variation law of these parameters in the full operating condition range. 2. The solution lacks completeness, failing to address the entire workflow of "how to systematically conduct full-condition testing, data processing, graph construction, and graph-based analysis and decision-making." Summary of the Invention

[0009] The purpose of this invention is to provide an engine combustion noise assessment method and apparatus. By utilizing in-cylinder pressure data and constructing a universal characteristic diagram of the maximum pressure rise rate, the combustion noise distribution characteristics of the engine under all operating conditions can be objectively and comprehensively characterized. This can improve the effectiveness of engine combustion noise level assessment, shorten the NVH performance development cycle, and reduce development costs.

[0010] To address the aforementioned technical problems, in a first aspect, the present invention provides a method for evaluating engine combustion noise, comprising at least: S1. Configure multiple pre-selected operating points under various engine load characteristics, and collect in-cylinder pressure signals for a preset number of cycles under each pre-selected operating point; S2. After preprocessing each cylinder pressure signal, integrate all preprocessed signals to calculate the characteristic value of each preselected operating point. S3. Based on the characteristic value of the operating point, the first engine parameter and the second engine parameter corresponding to each of the pre-selected operating points, one or more grid data points are generated on the preset parameter plane using a preset data point generation algorithm, and then the universal characteristic diagram of the maximum pressure rise rate is drawn. S4. Determine the engine combustion noise assessment result based at least on the universal characteristic diagram of the maximum pressure rise rate.

[0011] Optionally, step S2 specifically includes at least: After preprocessing each cylinder pressure signal, the pressure rise rate is calculated based on each preprocessed signal, and the maximum pressure rise rate value under each preset cycle is extracted. Then, the corresponding operating point feature value is calculated based on the maximum pressure rise rate value corresponding to all preset cycles under any preset operating point.

[0012] Optionally, the characteristic value of the operating point is at least the average value of the maximum pressure rise rate corresponding to all the preset cycles under each of the preselected operating points.

[0013] Optionally, the characteristic value of the operating point is at least the maximum value of the maximum pressure rise rate corresponding to all the preset cycles under each of the preselected operating points.

[0014] Optionally, step S3 specifically includes at least: Using at least the first engine parameter as the X-axis, the second engine parameter as the Y-axis, and the operating point characteristic value as the Z-axis, one or more grid data points are generated on the preset parameter plane using any interpolation algorithm, and then at least a contour map or cloud map is drawn to obtain the universal characteristic map of the maximum pressure rise rate.

[0015] Optionally, step S4 specifically includes at least: Based at least on the density and / or magnitude of the contour lines in the maximum pressure rise rate universal characteristic diagram, the combustion noise distribution of the engine under various engine load characteristics can be identified, and at least the optimal low-noise operating area, the noise abnormal area, or the cause of the noise abnormality can be located.

[0016] Optionally, step S4 specifically includes at least: Based at least on the density and / or magnitude of the contour lines in the maximum pressure rise universal characteristic diagram, the combustion noise distribution of the engine under various engine load characteristics is identified, and the engine injection control strategy is adjusted accordingly.

[0017] Optionally, the first engine parameter is at least the engine speed, and the second engine parameter is at least the engine load.

[0018] Optionally, the engine load is at least one of torque, mean effective pressure, throttle pedal opening percentage, indicated mean effective pressure, fuel injection quantity, and air-fuel ratio.

[0019] Based on the same concept, in a second aspect, the present invention also provides an engine combustion noise assessment device for performing the engine combustion noise assessment method described in any one of the first aspects; The engine combustion noise assessment device includes at least: The signal acquisition module is used to configure multiple pre-selected operating points under various engine load characteristics, and to acquire a preset number of in-cylinder pressure signals at each of the pre-selected operating points. The feature value calculation module is used to calculate the feature value of each of the pre-selected operating conditions by integrating all pre-processed signals after pre-processing each of the in-cylinder pressure signals. The characteristic diagram drawing module is used to generate one or more grid data points on a preset parameter plane using a preset data point generation algorithm, based on at least the characteristic value of the operating point corresponding to each of the pre-selected operating points, the first engine parameter and the second engine parameter, thereby drawing the universal characteristic diagram of the maximum pressure rise rate. The result determination module is used to determine the engine combustion noise assessment result based at least on the maximum pressure rise rate universal characteristic diagram.

[0020] The technical solution provided by this invention firstly configures multiple pre-selected operating points under various engine load characteristics, and collects a preset number of in-cylinder pressure signals at each pre-selected operating point; further, after preprocessing each in-cylinder pressure signal, it integrates all preprocessed signals to calculate the operating point feature values ​​of each pre-selected operating point; further, based on at least the operating point feature values ​​corresponding to each pre-selected operating point, the first engine parameters, and the second engine parameters, it uses a preset data point generation algorithm to generate one or more grid data points on a preset parameter plane, thereby drawing a universal characteristic diagram of the maximum pressure rise rate; finally, it determines the engine combustion noise assessment result based at least on the universal characteristic diagram of the maximum pressure rise rate. Therefore, this invention utilizes in-cylinder pressure data to construct a universal characteristic diagram of the maximum pressure rise rate to objectively and comprehensively characterize the combustion noise distribution characteristics of the engine under all operating conditions, which can improve the effectiveness of engine combustion noise level assessment, shorten the NVH performance development cycle, and reduce development costs. Attached Figure Description

[0021] Figure 1 This is a flowchart of an engine combustion noise assessment method provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of an engine combustion noise assessment device provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of a comparison curve of the variation of engine radiated noise with maximum pressure rise rate provided by an embodiment of the present invention; Figure 4 This is a schematic diagram of the universal characteristics of the maximum pressure rise rate of an engine before optimization, provided by an embodiment of the present invention; Figure 5 This is a schematic diagram of the universal characteristics of the maximum pressure rise rate of an engine after optimization, provided by an embodiment of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0023] It should be noted that any symbols and / or numbers present in the specification that are not marked in the accompanying drawings are not reference numerals.

[0024] Figure 1This is a flowchart of an engine combustion noise assessment method provided by an embodiment of the present invention. This embodiment is applicable to at least any vehicle internal combustion engine performance testing and noise and vibration (NVH) assessment scenario. The engine combustion noise assessment method can be, but is not limited to, executed by the engine combustion noise assessment device in this embodiment of the present invention as the execution subject, which can be implemented in software and / or hardware. Figure 1 As shown, the engine combustion noise assessment method includes at least the following steps: S1. Configure multiple pre-selected operating points under various engine load characteristics, and collect the in-cylinder pressure signal of a preset number of cycles at each pre-selected operating point.

[0025] The various engine load characteristics can cover both full-load and partial-load characteristics of the engine. Furthermore, the multiple preset operating points can be a series of speeds and load points. It is understood that the preset number of cycles can be adaptively configured according to the actual engine conditions, and this invention does not limit this.

[0026] More specifically, step S1 essentially involves data acquisition. The engine under test can be placed on an engine bench and then connected to a dynamometer and a combustion analysis system. Under the engine's full-load and partial-load characteristics, a series of speeds and load points (e.g., throttle / torque points) are set to cover the engine's entire commonly used operating range. At each pre-selected operating point, cylinder pressure signals are continuously acquired for multiple cycles (e.g., 100-200 cycles) using cylinder pressure sensors installed inside the cylinders.

[0027] S2. After preprocessing the pressure signal in each cylinder, integrate all preprocessed signals to calculate the characteristic value of each preselected operating point.

[0028] Preprocessing may include error signal removal, signal filtering, etc.

[0029] In one specific implementation, step S2 may optionally include at least the following: After preprocessing the pressure signal in each cylinder, the pressure rise rate is calculated based on each preprocessed signal, and the maximum pressure rise rate value under each preset cycle is extracted. Then, the corresponding operating point characteristic value is calculated based on the maximum pressure rise rate value corresponding to all preset cycles under any preselected operating point.

[0030] In another specific implementation, optionally, the characteristic value of the operating point is at least the average value of the maximum pressure rise rate corresponding to all preset cycles under each preselected operating point.

[0031] In another specific implementation, optionally, the characteristic value of the operating point is at least the maximum value of the maximum pressure rise rate corresponding to all preset cycles under each preselected operating point.

[0032] Specifically, step S2 essentially involves data processing and maximum pressure rise rate calculation. First, the in-cylinder pressure signal for each pre-selected operating point is processed, including but not limited to removing abnormal cycles and performing smoothing filtering to eliminate high-frequency noise interference. Then, the derivative of the pressure data for each processed cycle (i.e., the aforementioned pre-processed signal) is calculated to determine the pressure rise rate dp / dφ (where p is the in-cylinder pressure and φ is the crankshaft angle), and the maximum pressure rise rate value for that cycle is extracted and denoted as PRR_max. Finally, the statistical average of PRR_max under all preset cycles for that pre-selected operating point (or the maximum value at a certain confidence level according to design requirements) is calculated as the characteristic value PRR_avg for that pre-selected operating point.

[0033] S3. Based on the characteristic values ​​of the operating point corresponding to each pre-selected operating point, the first engine parameter and the second engine parameter, generate one or more grid data points on the preset parameter plane using a preset data point generation algorithm, and then draw the universal characteristic diagram of the maximum pressure rise rate.

[0034] There are multiple options for selecting the parameters of the first engine and the second engine.

[0035] In yet another specific implementation, step S3 may optionally include at least the following: Using at least the first engine parameter as the X-axis, the second engine parameter as the Y-axis, and the operating point characteristic value as the Z-axis, one or more grid data points are generated on the preset parameter plane using any interpolation algorithm, and then at least contour maps or cloud maps are drawn to obtain the universal characteristic map of the maximum pressure rise rate.

[0036] In yet another specific implementation, optionally, the first engine parameter is at least the engine speed, and the second engine parameter is at least the engine load.

[0037] In yet another specific embodiment, the engine load may optionally be at least one of torque, mean effective pressure, throttle pedal opening percentage, indicated mean effective pressure, fuel injection quantity, and air-fuel ratio.

[0038] It is understandable that step S3 essentially involves constructing a universal characteristic map of the maximum pressure rise rate. For example, engine speed (n, unit: rpm) is used as the X-axis, engine load (e.g., mean effective pressure BMEP, unit: bar; or torque Tq, unit: Nm) as the Y-axis, and the characteristic value PRR_avg of each operating point calculated in step S2 as the Z-axis. Further, using interpolation algorithms (e.g., bilinear interpolation, cubic spline interpolation, etc.), sufficiently dense grid data points are generated on the speed-load plane (i.e., the aforementioned preset parameter plane). These grid data points can be either a preset number or a preset density. Finally, a contour map or color cloud map (or other types of maps, such as a three-dimensional map—a three-dimensional surface map) is drawn to obtain the universal characteristic map of the maximum pressure rise rate.

[0039] S4. Determine the engine combustion noise assessment results at least based on the universal characteristic diagram of the maximum pressure rise rate.

[0040] The engine combustion noise evaluation results can be adapted to the actual engine configuration, and this invention does not limit this.

[0041] In yet another specific implementation, step S4 may optionally include at least the following: Based at least on the density and / or magnitude of the contour lines in the maximum pressure rise rate universal characteristic diagram, identify the combustion noise distribution of the engine under various engine load characteristics, and at least locate the optimal low-noise operating area, the noise abnormal area, or the cause of the noise abnormality.

[0042] In yet another specific implementation, step S4 may optionally include at least the following: Based at least on the density and / or magnitude of the contour lines in the maximum pressure rise rate universal characteristic diagram, the combustion noise distribution of the engine under various engine load characteristics can be identified, and the engine injection control strategy can be adjusted accordingly.

[0043] As can be seen, step S4 essentially involves combustion noise analysis and characterization. For example, based on the universal characteristic diagram of the maximum pressure rise rate obtained in step S3, the distribution of combustion noise under all operating conditions can be intuitively identified according to the density and numerical values ​​of the contour lines in the diagram. Areas with higher PRR_avg values ​​(corresponding to larger contour line values ​​and darker colors) represent more aggressive combustion under that operating condition and a greater potential for combustion noise radiation. By comparing the universal characteristic diagrams of different schemes (such as different injectors, different combustion chamber shapes, and different injection strategies), the impact of each scheme on the overall combustion noise of the engine can be quantitatively evaluated, and the optimal low-noise operating area can be located.

[0044] The technical solution provided in this embodiment firstly configures multiple pre-selected operating points under various engine load characteristics, and collects a preset number of in-cylinder pressure signals at each pre-selected operating point. Further, after preprocessing each in-cylinder pressure signal, all preprocessed signals are integrated to calculate the operating point feature values ​​for each pre-selected operating point. Further still, based at least on the operating point feature values ​​corresponding to each pre-selected operating point, the first engine parameter, and the second engine parameter, a preset data point generation algorithm is used to generate one or more grid data points on a preset parameter plane, thereby drawing a universal characteristic diagram of the maximum pressure rise rate. Finally, the engine combustion noise assessment result is determined at least based on the universal characteristic diagram of the maximum pressure rise rate. Therefore, this embodiment utilizes in-cylinder pressure data to construct a universal characteristic diagram of the maximum pressure rise rate to objectively and comprehensively characterize the combustion noise distribution characteristics of the engine under all operating conditions, which can improve the effectiveness of engine combustion noise level assessment, shorten the NVH performance development cycle, and reduce development costs.

[0045] It should be noted that the present invention can achieve at least the following technical effects: 1) Objectivity: The maximum pressure rise rate calculated based on measured cylinder pressure data is used as the evaluation index, which avoids human error in subjective evaluation methods. The evaluation results are objective, quantifiable and reproducible.

[0046] 2) Comprehensiveness: By constructing a universal characteristic diagram, the originally scattered and isolated single-point operating condition information is integrated into a continuous global view, which can clearly reveal the combustion noise distribution characteristics of the engine under all operating conditions, avoiding the one-sidedness of single-point evaluation.

[0047] 3) Intuitive and guiding: The universal characteristic diagram presents data in a graphical way, enabling engineers to quickly locate the "high-risk zone" and "low-risk zone" of combustion noise. It provides intuitive and effective technical guidance and quantitative basis for the optimized design of the combustion system and the refined calibration of the fuel injection control strategy, which helps to shorten the NVH performance development cycle and reduce development costs.

[0048] 4) Diagnostic value: When abnormal noise occurs in the engine, the operating conditions and causes of the abnormal noise can be quickly diagnosed by comparing the maximum pressure rise rate universal characteristic diagram of the engine with that of the standard prototype, which greatly improves the diagnostic efficiency.

[0049] 5) Environmental universality: The implementation process of this invention has no special requirements for the acoustic environment and can be carried out on a regular test bench, rather than an anechoic chamber.

[0050] It should also be noted that the following scenario embodiment is provided to illustrate the aforementioned technical solutions.

[0051] (1) Test preparation A four-cylinder high-pressure common rail engine is mounted on an electric dynamometer stand. A blow-pressure hole needs to be pre-drilled in the cylinder head, and a piezoelectric cylinder pressure sensor needs to be installed and connected to the combustion analyzer. A corner marker is installed at the front of the engine, with a sampling resolution set to 0.1°CA. The corner marker signal is then connected to the combustion analyzer. If the engine's firing uniformity is assumed to be good, a blow-pressure sensor only needs to be installed in one cylinder.

[0052] Configure all settings in the host computer software, including setting a 3000Hz low-pass filter. Use a dynamometer to reverse-drive the engine to complete the top dead center calibration and finish the test preparation.

[0053] (2) Data collection Start the engine and warm it up to normal operating conditions (coolant temperature 85±2℃, oil temperature 90±2℃). Set the test operating points: speed from 1200rpm to 3000rpm, taking a point every 200rpm; load (torque) from 50Nm to maximum torque, taking a point every 50Nm. At each stable operating point (i.e., the aforementioned pre-selected operating points), after the engine runs stably, the combustion analyzer continuously collects and saves cylinder pressure data for 100 cycles. For example, Figure 3 This is a schematic diagram of a comparison curve of the variation of engine radiated noise with maximum pressure rise rate provided by an embodiment of the present invention.

[0054] (3) Data processing and plotting After the test, the cylinder pressure data for each operating point can be processed using the post-processing software built into the combustion analyzer (i.e., the aforementioned host computer software): 1) Average the cylinder pressure data of 100 cycles to obtain the average cylinder pressure curve.

[0055] 2) Differentiate the average cylinder pressure curve to obtain the pressure rise rate curve.

[0056] 3) Find the maximum value of the pressure rise rate curve and use it as the maximum pressure rise rate characteristic value PRR_avg for that operating condition.

[0057] Compile the speed, load, and corresponding PRR_avg values ​​for all operating points into a data table. Import this data table into any data processing software (such as UniPlot, MATLAB, Origin, etc.), selecting "Speed" as the X-axis, "Load" as the Y-axis, and "PRR_avg" as the Z-value. Using the biharmonic interpolation method, generate a 100×100 grid on the XY plane and draw a color-filled contour plot, thus obtaining the following... Figure 4 The diagram shown is the "Universal Characteristic Diagram of Maximum Pressure Rise Rate of the Original Machine Scheme". To be precise, Figure 4 This is a schematic diagram of the universal characteristics of the maximum pressure rise rate of an engine before optimization, provided by an embodiment of the present invention.

[0058] (4) Comparison and analysis of the schemes Depend on Figure 4 It is clear that the original design has a significant combustion noise "hot zone" in the 50Nm range around 2800rpm, with the highest contour value being 6bar / deg, which is higher than other load conditions at the same speed. This is a combustion noise spike that can be optimized.

[0059] To address this issue, the engine's fuel injection control strategy is adjusted (e.g., reducing rail pressure, increasing pre-injection quantity, and optimizing main injection timing within this region). For the optimized solution, steps S2 and S3 are repeated to obtain the following result. Figure 5 The diagram shown is a "universal characteristic diagram of the maximum pressure rise rate of the optimized scheme". To be precise, Figure 5 This is a schematic diagram of the universal characteristics of the maximum pressure rise rate of an engine after optimization, provided by an embodiment of the present invention.

[0060] contrast Figure 4 and Figure 5 It can be seen that the optimization scheme effectively reduced the PRR_avg value of the "hot zone," with most areas dropping below 4 bar / deg, which is comparable to or even lower than the level under other load conditions at the same speed. More specifically, Figure 3 The paper shows a comparison of the trends of radiated noise and maximum pressure rise rate of a certain engine under stable operating conditions. By adjusting the pre-injection amount, the combustion noise is changed, thereby changing the overall radiated noise of the engine. It can be seen that the trends of the two are basically consistent. Figure 4 The original engine configuration showed that PRR_avg was below 8 bar / deg in the entire map, with the maximum value appearing in the high load region of 1200-1600 rpm. However, there was a significant combustion noise "hot zone" near 2800 rpm in the 50 Nm region, which was higher than other load conditions at the same speed, and was a combustion noise protrusion. Figure 5 After optimization, the contour values ​​in this area decreased from 6 bar / deg to 4 bar / deg, indicating that combustion noise was effectively controlled.

[0061] Through the above process, this scenario embodiment successfully visualized and quantified the engine combustion noise problem, and verified the effectiveness of the optimization scheme.

[0062] It is understood that this scenario implementation can achieve the following: 1) Selection and correlation of indicators: The core combustion parameter of "maximum pressure rise rate" was creatively selected as a proxy evaluation indicator of "combustion noise", and the technical correlation between the two was established.

[0063] 2) Data dimension expansion: The maximum pressure rise rate data under traditional single-point and discrete working conditions is expanded to the entire speed-load plane through mathematical methods, so that it changes from "point" information to "area" information.

[0064] 3) Visual representation: Using a two-dimensional graphic form such as a "universal characteristic diagram" (contour map / cloud map) or a three-dimensional surface map, the three-dimensional data (speed, load, maximum pressure rise rate) are presented in an intuitive and comprehensive way, making the complex combustion noise distribution pattern clear at a glance.

[0065] 4) Application of the method: The method is applied to multiple aspects such as the optimization design of engine combustion system, control strategy calibration and fault diagnosis.

[0066] It should also be noted that several technical solutions that can be improved or replaced are provided below.

[0067] 1. Improvements to the method for obtaining the characteristic value of "maximum pressure rise rate". Alternative Solution A (Multi-cylinder Processing): For steps S1 and S2, for multi-cylinder engines, in addition to data acquisition and analysis of individual cylinders (e.g., the first cylinder), in-cylinder pressure data of all cylinders can be acquired simultaneously or sequentially. The final "maximum pressure rise rate universal characteristic diagram" can use the average, maximum, or specific statistical quantile (e.g., the 90th percentile) of the maximum pressure rise rate of all cylinders as the Z-value. This provides a more comprehensive reflection of the overall engine's combustion noise consistency.

[0068] Alternative Option B (Considering Cyclic Volatility): When calculating the maximum pressure rise rate characteristic value, in addition to directly averaging, the cyclic volatility coefficient (COV) can be introduced. That is, after removing abnormally harsh cycles (such as cycles exceeding three standard deviations of the average), the average of the remaining cycles is calculated to improve the robustness and stability of the evaluation index.

[0069] 2. Improvements to the horizontal and vertical axes of the "Universal Property Diagram" Alternative solution (load coordinate replacement): For step S3, the "engine load" represented by the vertical axis is not limited to torque (Nm) or mean effective pressure (BMEP, bar), but can also be any parameter that can characterize the engine load level, such as throttle pedal opening percentage (%), indicated mean effective pressure (IMEP), fuel injection quantity (mg / cyc), or air-fuel ratio. Choosing different coordinate parameters can be applied to the needs of different development stages (such as throttle opening commonly used in the vehicle calibration stage).

[0070] 3. Improvements regarding application scenarios and comparison objects Alternative Solution A (Comparison with Standard / Limit Values): The application of this method is not limited to comparing two different hardware / software solutions. Pre-set combustion noise limit curves (or limit surfaces) can also be directly plotted on the maximum pressure rise rate universal characteristic diagram. If the measured value in a certain operating condition range of the engine exceeds the limit, the system can automatically issue an alarm or mark the violation, thereby achieving the compliance determination function.

[0071] Alternative Solution B (Time-Domain Evolution Analysis): For the same engine, plot the universal characteristic diagram of maximum pressure rise rate at multiple time points before, during, and after durability testing (such as a 1000-hour alternating load test). By comparing the changes in these plots, the evolution of engine combustion noise characteristics with wear, carbon deposits, and other phenomena can be analyzed, which can be used for health management and life prediction.

[0072] 4. Improvements to data acquisition and processing hardware Alternative Solution: The data acquisition in step S1 can be performed without relying on a dedicated cylinder pressure sensor and an expensive combustion analyzer. The cylinder head vibration signal can be acquired using a vibration acceleration sensor mounted on the engine cylinder head, and the cylinder pressure signal can be reconstructed using a calibrated transfer function to calculate the maximum pressure rise rate. This alternative solution significantly reduces the testing threshold and cost, making it more suitable for end-of-line (EOL) testing scenarios.

[0073] Figure 2 This is a schematic diagram of an engine combustion noise assessment device provided in an embodiment of the present invention. This embodiment is applicable to at least any vehicle internal combustion engine performance testing and noise and vibration (NVH) assessment scenario. The engine combustion noise assessment device can be implemented using software and / or hardware. Figure 2 As shown, the engine combustion noise assessment device includes at least: The signal acquisition module 110 is used to configure multiple pre-selected operating points under various engine load characteristics, and to acquire a preset number of in-cylinder pressure signals at each pre-selected operating point. The feature value calculation module 120 is used to calculate the feature value of each pre-selected working condition point by integrating all pre-processed signals after pre-processing the pressure signal in each cylinder. The characteristic diagram drawing module 130 is used to generate one or more grid data points on the preset parameter plane using a preset data point generation algorithm, based on at least the characteristic value of the operating point corresponding to each pre-selected operating point, the first engine parameter and the second engine parameter, thereby drawing the universal characteristic diagram of the maximum pressure rise rate. Result determination module 140 is used to determine the engine combustion noise assessment result based at least on the universal characteristic diagram of the maximum pressure rise rate.

[0074] Optionally, the eigenvalue calculation module 120 is specifically used for at least: After preprocessing the pressure signal in each cylinder, the pressure rise rate is calculated based on each preprocessed signal, and the maximum pressure rise rate value under each preset cycle is extracted. Then, the corresponding operating point characteristic value is calculated based on the maximum pressure rise rate value corresponding to all preset cycles under any preselected operating point.

[0075] Optionally, the characteristic value of the operating point is at least the average value of the maximum pressure rise rate corresponding to all preset cycles under each preselected operating point.

[0076] Optionally, the characteristic value of the operating point is at least the maximum value of the maximum pressure rise rate corresponding to all preset cycles under each pre-selected operating point.

[0077] Optionally, the feature plotting module 130 is specifically used for at least: Using at least the first engine parameter as the X-axis, the second engine parameter as the Y-axis, and the operating point characteristic value as the Z-axis, one or more grid data points are generated on the preset parameter plane using any interpolation algorithm, and then at least contour maps or cloud maps are drawn to obtain the universal characteristic map of the maximum pressure rise rate.

[0078] Optionally, the result determination module 140 is specifically used for at least: Based at least on the density and / or magnitude of the contour lines in the maximum pressure rise rate universal characteristic diagram, identify the combustion noise distribution of the engine under various engine load characteristics, and at least locate the optimal low-noise operating area, the noise abnormal area, or the cause of the noise abnormality.

[0079] Optionally, the result determination module 140 is specifically used for at least: Based at least on the density and / or magnitude of the contour lines in the maximum pressure rise rate universal characteristic diagram, the combustion noise distribution of the engine under various engine load characteristics can be identified, and the engine injection control strategy can be adjusted accordingly.

[0080] Optionally, the first engine parameter is at least the engine speed, and the second engine parameter is at least the engine load.

[0081] Optionally, the engine load is at least one of torque, mean effective pressure, throttle pedal opening percentage, indicated mean effective pressure, fuel injection quantity, and air-fuel ratio.

[0082] The technical solution provided in this embodiment firstly configures multiple pre-selected operating points under various engine load characteristics through a signal acquisition module, and acquires a preset number of in-cylinder pressure signals at each pre-selected operating point. Further, after preprocessing each in-cylinder pressure signal through a feature value calculation module, it integrates all preprocessed signals to calculate the operating point feature values ​​for each pre-selected operating point. Further, based on the operating point feature values, first engine parameters, and second engine parameters corresponding to each pre-selected operating point, a feature map drawing module generates one or more grid data points on a preset parameter plane using a preset data point generation algorithm, thereby drawing a universal characteristic map of the maximum pressure rise rate. Finally, a result determination module determines the engine combustion noise assessment result based at least on the universal characteristic map of the maximum pressure rise rate. Therefore, this embodiment utilizes in-cylinder pressure data to construct a universal characteristic map of the maximum pressure rise rate to objectively and comprehensively characterize the combustion noise distribution characteristics of the engine under all operating conditions, which can improve the effectiveness of engine combustion noise level assessment, shorten the NVH performance development cycle, and reduce development costs.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for evaluating engine combustion noise, characterized in that, At least including: S1. Configure multiple pre-selected operating points under various engine load characteristics, and collect in-cylinder pressure signals for a preset number of cycles under each pre-selected operating point; S2. After preprocessing each cylinder pressure signal, integrate all preprocessed signals to calculate the characteristic value of each preselected operating point. S3. Based on the characteristic value of the operating point, the first engine parameter and the second engine parameter corresponding to each of the pre-selected operating points, one or more grid data points are generated on the preset parameter plane using a preset data point generation algorithm, and then the universal characteristic diagram of the maximum pressure rise rate is drawn. S4. Determine the engine combustion noise assessment result based at least on the universal characteristic diagram of the maximum pressure rise rate.

2. The engine combustion noise assessment method according to claim 1, characterized in that, Step S2 specifically includes at least the following: After preprocessing each cylinder pressure signal, the pressure rise rate is calculated based on each preprocessed signal, and the maximum pressure rise rate value under each preset cycle is extracted. Then, the corresponding operating point feature value is calculated based on the maximum pressure rise rate value corresponding to all preset cycles under any preset operating point.

3. The engine combustion noise assessment method according to claim 2, characterized in that, The characteristic value of the operating point is at least the average value of the maximum pressure rise rate corresponding to all the preset cycles under each of the pre-selected operating points.

4. The engine combustion noise assessment method according to claim 2, characterized in that, The characteristic value of the operating point is at least the maximum value of the maximum pressure rise rate corresponding to all the preset cycles under each of the pre-selected operating points.

5. The engine combustion noise assessment method according to claim 1, characterized in that, Step S3 specifically includes at least the following: Using at least the first engine parameter as the X-axis, the second engine parameter as the Y-axis, and the operating point characteristic value as the Z-axis, one or more grid data points are generated on the preset parameter plane using any interpolation algorithm, and then at least a contour map or cloud map is drawn to obtain the universal characteristic map of the maximum pressure rise rate.

6. The engine combustion noise assessment method according to claim 5, characterized in that, Step S4 specifically includes at least the following: Based at least on the density and / or magnitude of the contour lines in the maximum pressure rise rate universal characteristic diagram, the combustion noise distribution of the engine under various engine load characteristics can be identified, and at least the optimal low-noise operating area, the noise abnormal area, or the cause of the noise abnormality can be located.

7. The engine combustion noise assessment method according to claim 5, characterized in that, Step S4 specifically includes at least the following: Based at least on the density and / or magnitude of the contour lines in the maximum pressure rise universal characteristic diagram, the combustion noise distribution of the engine under various engine load characteristics is identified, and the engine injection control strategy is adjusted accordingly.

8. The engine combustion noise assessment method according to claim 5, characterized in that, The first engine parameter is at least the engine speed, and the second engine parameter is at least the engine load.

9. The engine combustion noise assessment method according to claim 8, characterized in that, The engine load is at least one of torque, mean effective pressure, throttle pedal opening percentage, indicated mean effective pressure, fuel injection quantity, and air-fuel ratio.

10. An engine combustion noise assessment device, characterized in that, Used to perform the engine combustion noise assessment method according to any one of claims 1-9; The engine combustion noise assessment device includes at least: The signal acquisition module is used to configure multiple pre-selected operating points under various engine load characteristics, and to acquire a preset number of in-cylinder pressure signals at each of the pre-selected operating points. The feature value calculation module is used to calculate the feature value of each of the pre-selected operating conditions by integrating all pre-processed signals after pre-processing each of the in-cylinder pressure signals. The characteristic diagram drawing module is used to generate one or more grid data points on a preset parameter plane using a preset data point generation algorithm, based on at least the characteristic value of the operating point corresponding to each of the pre-selected operating points, the first engine parameter and the second engine parameter, thereby drawing the universal characteristic diagram of the maximum pressure rise rate. The result determination module is used to determine the engine combustion noise assessment result based at least on the maximum pressure rise rate universal characteristic diagram.

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