New energy automobile power assembly vibration energy analysis and evaluation method and system

Abstract

The application provides a new energy automobile power assembly vibration energy analysis and evaluation method and system, the method comprises the following steps: obtaining a power assembly numerical model, and obtaining first material information of each component corresponding to an engine origin and second material information of each component in the power assembly numerical model; establishing a grid and a finite element model; based on the finite element model, reducing the first material information and the second material information, and inputting cylinder pressure excitation under a steady state working condition to the finite element model to obtain an adaptive dynamics model; running the adaptive dynamics model to obtain intermediate data, and post-processing acceleration data of a cylinder body surface and a suspension driving end of the engine to obtain post-processing time domain data; based on the time domain data, judging whether the half-order vibration energy of the engine meets an acceptance limit value; and optimizing the engine that does not meet the acceptance limit value. The application provides an evaluation method and standard for half-order vibration energy, and provides an evaluation basis for early forward simulation.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle powertrain technology, and in particular to a method and system for analyzing and evaluating the vibration energy of a new energy vehicle powertrain. Background Technology

[0002] Hybrid-specific engines prioritize thermal efficiency. While employing a more efficient combustion system, they also require lightweight hardware design to reduce engine friction. Their crankshaft system is thinner and lighter than that of traditional engines, resulting in a half-order knocking noise problem. This issue is more pronounced during parking and charging, severely impacting the sound quality inside the vehicle and has become an industry challenge.

[0003] The semi-step knocking issue in the hybrid powertrain manifests subjectively as a regular "thump-thump" sound, which is clearly perceptible during parking and generator operation. The mechanism is as follows: Under normal explosion pressure excitation, the engine crankshaft system undergoes bending deformation, which is radiated outwards through the outer surface of the hybrid powertrain.

[0004] Currently, industry solutions for optimizing half-order vibration energy in hybrid powertrains are primarily focused on the mid-stage of project development, after the powertrain or test vehicle has been completed. Problems are identified and corrective measures are proposed, including adjusting rear flywheel parameters and crankshaft optimization. These solutions, at this mid-stage, significantly impact the overall project development schedule. Currently, there are no readily available technologies in the industry for early-stage forward simulation and half-order vibration energy evaluation metrics. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for vibration energy analysis and evaluation of powertrain in new energy vehicles, which aims to solve the technical problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] A method for vibration energy analysis and evaluation of a new energy vehicle powertrain includes the following steps:

[0008] Obtain the powertrain digital model of the new energy vehicle, and obtain the first material information of each component in the powertrain digital model corresponding to the engine origin, and the second material information of each component in the powertrain digital model itself;

[0009] Based on the first material information and the second material information, a mesh and finite element model are established;

[0010] The finite element model is reduced in size, and cylinder pressure excitation under steady-state conditions is input into the finite element model to obtain an adaptive dynamic model;

[0011] Solve the adaptive dynamics model to obtain acceleration data of the engine cylinder block surface and the active suspension end, and post-process the acceleration data to obtain post-processed time domain data.

[0012] Based on the post-processed time-domain data, it is determined whether the half-order vibration energy of the engine meets the acceptance limit.

[0013] Engines that do not meet the acceptance limits will be optimized.

[0014] According to one aspect of the above technical solution, the components in the powertrain digital model include the engine, suspension, hybrid transmission, dual-mass flywheel, and exhaust hot end.

[0015] According to one aspect of the above technical solution, the first material information includes the center of mass and the moment of inertia, and the second material information includes the stiffness and damping of the suspension, the moment of inertia of the dual-mass flywheel, the spring ratio of the dual-mass flywheel, the frequency of the front damping pulley of the engine, and the cylinder pressure curve data of the engine under typical steady-state conditions.

[0016] According to one aspect of the above technical solution, the specific steps for determining whether the half-order vibration energy of the engine meets the acceptance limit based on the post-processed time-domain data include:

[0017] Calculate the root mean square value of the total vibration energy of all cylinders in the engine in one complete cycle, and calculate the root mean square value of the individual vibration energy of each cylinder in the engine during the ignition cycle.

[0018] The average root mean square value of the total vibration energy of each cylinder is compared with the average root mean square value of the individual vibration energy to obtain the acceptance limit, and to determine whether the half-order vibration energy of the entire engine is qualified.

[0019] According to one aspect of the above technical solution, the specific steps for calculating the vibration energy value of each cylinder within the engine during the ignition cycle include:

[0020] The post-processed time-domain data is subjected to bandpass filtering to obtain filtered time-domain data. The frequency of the bandpass filtering is 200Hz~800Hz.

[0021] The filtered time-domain data of all cylinders in the engine in one complete cycle is obtained, and the filtered time-domain data of each cylinder in the engine in the ignition cycle is obtained.

[0022] Obtain the crankshaft rotation angle data within the engine body at the calibrated angle;

[0023] The acquired crankshaft angle data is divided equally into several crankshaft angle components, and the number of crankshaft angle components is the same as the number of cylinder blocks.

[0024] Each crankshaft angle component is correlated with the ignition cycle of each cylinder block, and the root mean square value of the single vibration energy of each cylinder block in the filtered time domain data within the ignition cycle is calculated.

[0025] Calculate the root mean square value of the overall vibration energy of the filtered time-domain data for all cylinders within one complete cycle.

[0026] According to one aspect of the above technical solution, the specific steps of comparing the average root mean square value of the overall vibration energy of each cylinder block with the average root mean square value of the individual vibration energy to obtain an acceptance limit and determining whether the half-order vibration energy of the entire engine is qualified include:

[0027] A comparison formula is created by substituting the average root mean square value of the total vibration energy and the average root mean square value of the individual vibration energy into the comparison formula to obtain the size ratio value.

[0028] The size ratio values ​​in the database are processed and compared to determine the acceptable limit.

[0029] Engines whose size ratio exceeds the acceptance limit are considered to have unacceptable half-order vibration energy.

[0030] According to one aspect of the above technical solution, the specific steps for optimizing the engine that does not meet the acceptance limit include:

[0031] Based on the actual situation of the hybrid powertrain of the new energy vehicle, the internal and external component modes of the engine are optimized to decouple the crankshaft system mode within the engine.

[0032] This invention also provides a vibration energy analysis and evaluation system for a new energy vehicle powertrain, comprising:

[0033] Acquisition module: used to acquire the powertrain digital model of new energy vehicles, and to acquire the first material information of each component in the powertrain digital model corresponding to the engine origin, and the second material information of each component in the powertrain digital model itself;

[0034] The module for building a mesh and a finite element model is used to build the mesh and the finite element model based on the first material information and the second material information.

[0035] Excitation module: used to reduce the finite element model and input the cylinder pressure excitation under steady-state conditions into the finite element model to obtain an adaptive dynamic model;

[0036] Processing module: used to solve the adaptive dynamics model, obtain acceleration data of the engine cylinder block surface and the active suspension end, and post-process the acceleration data to obtain post-processed time domain data;

[0037] Judgment module: used to determine whether the half-order vibration energy of the engine meets the acceptance limit based on the post-processed time-domain data;

[0038] Optimization module: Used to optimize engines that do not meet the acceptance limits.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] This invention proposes a method and standard for evaluating half-order vibration energy, providing an evaluation basis for early-stage forward simulation. For the industry-wide challenge of half-order impact in hybrid vehicles, it enables early-stage forward simulation and evaluation. Without freezing the relevant hardware design, it allows for hardware optimization and modification, avoiding material waste and saving project development costs and valuable development time. Attached Figure Description

[0041] Figure 1 This is a flowchart of the vibration energy analysis and evaluation method for the powertrain of new energy vehicles in the first embodiment of the present invention;

[0042] Figure 2 This is a structural block diagram of the vibration energy analysis and evaluation system for the powertrain of a new energy vehicle according to the second embodiment of the present invention;

[0043] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0044] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of the invention are illustrated in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0045] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0047] Please see Figure 1 The image shows a method for analyzing and evaluating the vibration energy of a new energy vehicle powertrain according to the first embodiment of the present invention, which includes the following steps:

[0048] S10, obtain the powertrain digital model of the new energy vehicle, and obtain the first material information of each component in the powertrain digital model corresponding to the engine origin, and the second material information of each component in the powertrain digital model itself;

[0049] S20, Based on the first material information and the second material information, establish a mesh and a finite element model;

[0050] S30, the finite element model is reduced, and the cylinder pressure excitation under steady-state conditions is input into the finite element model to obtain an adaptive dynamic model;

[0051] S40, Solve the adaptive dynamics model to obtain the acceleration data of the engine cylinder block surface and the active suspension end, and post-process the acceleration data to obtain post-processed time domain data;

[0052] S50, based on the post-processed time-domain data, determine whether the engine's half-order vibration energy meets the acceptable limit;

[0053] S60 optimizes engines that do not meet the acceptance limits.

[0054] Understandably, this invention proposes a method and standard for evaluating half-order vibration energy, providing an evaluation basis for early-stage forward simulation. For the industry-wide challenge of half-order impact in hybrid vehicles, it enables early-stage forward simulation and evaluation, allowing for hardware optimization and modification without requiring the hardware design to be frozen, thus avoiding material waste, saving project development costs, and conserving valuable project development time.

[0055] Furthermore, in step S10, the components in the powertrain digital model include the engine, suspension, hybrid transmission, dual-mass flywheel, and exhaust hot end. The first material information includes the center of mass and moment of inertia, and the second material information includes the stiffness and damping of the suspension, the moment of inertia of the dual-mass flywheel, the spring ratio of the dual-mass flywheel, the frequency of the front damping pulley of the engine, and the cylinder pressure curve data of the engine under typical steady-state conditions. There are three typical steady-state conditions.

[0056] Furthermore, steps S30 and S40 are currently common methods used in the industry to obtain time-domain data of the engine block surface and the active suspension end, which will not be elaborated upon here, but only given a general description:

[0057] S30. Due to the large number of degrees of freedom in a complete finite element model, direct use for transient dynamic analysis is extremely costly and time-consuming. Model reduction aims to preserve the dynamic characteristics within the frequency range of interest while significantly reducing the model size. A common method is component modal synthesis, an industry standard approach. The entire finite element model is divided into several substructures (such as the engine assembly, hybrid transmission, etc.), and the modes of each substructure are calculated separately. Then, these substructure modes are assembled through interface degrees of freedom to form a reduced model of the entire system. A reduced model containing master nodes is generated. Master nodes are typically located at suspension connection points, excitation application points (such as the point of application of engine burst pressure), and response points of interest (such as measuring points on the cylinder block surface). All dynamic calculations are performed on these master nodes, resulting in extremely high efficiency. Load transformation is performed using the "cylinder pressure curve data of three typical steady-state conditions" obtained in the first step: the cylinder pressure curves are converted into forces and torques acting on the crankshaft main journal and connecting rod journal through the mechanical relationship of the crankshaft-connecting rod mechanism. In the reduced model, these forces and torques are applied as external excitations to the corresponding master nodes to obtain an adaptive dynamic model.

[0058] S40, then a transient dynamic analysis is performed to calculate the system's vibration response over time under cylinder pressure excitation. Analysis duration: at least covering multiple complete engine operating cycles to ensure the stability of the results.

[0059] Time step: Determined based on the highest frequency of interest (e.g., 1000Hz), satisfying the Nyquist sampling theorem; typically, the time step needs to be on the order of 0.0001 seconds. Damping setting: Input the modal damping ratio of the structure (usually based on empirical or experimental data, such as 2%~5% for steel structures). Calculation output: Run the dynamics solver to directly obtain the time-domain response data at the master nodes of interest, primarily acceleration. Key locations are the active suspension end: i.e., the acceleration at the connection point between the suspension and the powertrain; this is a key indicator for assessing vibration transmission to the frame, directly affecting the overall vehicle NVH performance. Cylinder block / cylinder head surfaces: Acceleration at these locations reflects the potential for structural radiated noise. Data post-processing steps include data slicing: removing initial transient responses and retaining stable periodic response data. RMS calculation: calculating the RMS value of the acceleration time-domain signal to assess the overall vibration level. Frequency domain processing (crucial): Fast Fourier Transform: converting the time-domain acceleration signal into a frequency-domain spectrum. Order analysis: This is the core of engine NVH analysis. The objective is to identify specific frequency components (orders) related to engine speed. Key orders: Focusing on the 0.5, 1st, 1.5, 2nd, etc., orders of combustion excitation, as well as the order of inertial force excitation. Results: A colormap is generated, clearly showing the changes in vibration of each order with frequency under different engine speeds (operating conditions), thus obtaining post-processed time-domain data.

[0060] Furthermore, the specific steps of step S50 include:

[0061] S51, calculate the root mean square value of the total vibration energy of all cylinders in the engine in a complete cycle, and calculate the root mean square value of the individual vibration energy of each cylinder in the engine during the ignition cycle.

[0062] S52, compare the average root mean square value of the total vibration energy of each cylinder block with the average root mean square value of the individual vibration energy to obtain the acceptance limit and determine whether the half-order vibration energy of the entire engine is qualified.

[0063] Furthermore, the specific steps of step S51 include:

[0064] The post-processed time-domain data is subjected to bandpass filtering to obtain filtered time-domain data. The frequency of the bandpass filtering is 200Hz~800Hz.

[0065] The filtered time-domain data of all cylinders in the engine in one complete cycle is obtained, and the filtered time-domain data of each cylinder in the engine in the ignition cycle is obtained.

[0066] Obtain the crankshaft rotation angle data within the engine body at a calibrated angle; the calibrated angle is 720°.

[0067] The acquired crankshaft angle data is divided into equal angles to obtain several crankshaft angle components. The number of crankshaft angle components is the same as the number of cylinder blocks. In this embodiment, the crankshaft angle is divided into 4 equal parts, namely 0°-180°, 180°-360°, 360°-540°, and 540°-720°.

[0068] Each crankshaft angle component is correlated with the ignition cycle of each cylinder block, and the root mean square value of the individual vibration energy of each cylinder block in the filtered time-domain data within the ignition cycle is calculated; that is, 0°-180° corresponds to the ignition cycle of the first cylinder, 180°-360° corresponds to the ignition cycle of the second cylinder, 360°-540° corresponds to the ignition cycle of the third cylinder, and 540°-720° corresponds to the ignition cycle of the fourth cylinder, which also represents the compression and power strokes; the formula for calculating the root mean square value of the individual vibration energy is:

[0069] ;

[0070] in, T1 represents the average root mean square value of the single vibration energy of a cylinder, T2 represents the start time of the ignition cycle of a cylinder (i.e., the compression bottom dead center), and T2 represents the end time of the ignition cycle of a cylinder (i.e., the power bottom dead center). f(t) represents the filtered time-domain data within the ignition cycle of a cylinder.

[0071] Calculate the overall average root mean square value of the vibration energy of the filtered time-domain data for all cylinders within one complete cycle;

[0072] ;

[0073] in, T3 represents the root mean square value of the total vibration energy of all cylinders in a complete cycle after filtering in the time domain. T2 represents the start time of the complete cycle (i.e., the bottom dead center of the first cylinder during compression), T3 represents the end time of the complete cycle (i.e., the bottom dead center of the last cylinder during power stroke), and f(t') represents the filtered time domain data in the complete cycle.

[0074] Furthermore, the specific steps of step S52 include:

[0075] A comparison formula is created by substituting the average root mean square value of the total vibration energy and the average root mean square value of the individual vibration energy into the comparison formula to obtain the size ratio value.

[0076] ;

[0077] in, R represents the size ratio of a cylinder. If R is positive, it means that the vibration energy of the cylinder during the ignition cycle is greater than the average energy of the cycle, and the larger the R value, the stronger the half-order vibration energy. If R is negative, it means that the vibration energy of the cylinder during the ignition cycle is less than the average energy of the cycle, and the cylinder has no half-order vibration problem.

[0078] The size ratio values ​​in the database were processed and compared to determine the acceptance limit; the acceptance standard for the R value was determined by processing and comparing massive amounts of historical measured data, and the following acceptance standard was finally confirmed: R≤25%.

[0079] Some data is shown below, where VER represents subjective rating; the higher the score, the better the subjective performance. VER7 indicates that the half-order knocking noise cannot be subjectively detected, VER6 indicates that it is subjectively identifiable but barely acceptable, and VER6 and below indicates that it is subjectively clearly identifiable but unacceptable. Initial simulations were performed based on a VER7 score.

[0080]

[0081] Engines whose size ratio exceeds the acceptance limit are considered to have unacceptable half-order vibration energy.

[0082] It should be noted that the filtered time-domain data here refers to the processed acceleration data of the cylinder block surface or the processed acceleration data of the active suspension end. For example, first input the processed acceleration data of the cylinder block surface to obtain the average root mean square value of individual vibration energy, the average root mean square value of overall vibration energy, and the magnitude ratio value. This constitutes one set of experiments. Then input the processed acceleration data of the active suspension end to obtain the average root mean square value of individual vibration energy, the average root mean square value of overall vibration energy, and the magnitude ratio value. This constitutes another set of experiments. Finally, the magnitude ratio values ​​in the database are processed and compared to determine the acceptance standard for the R value.

[0083] Furthermore, the specific steps of step S60 include:

[0084] Based on the actual situation of the hybrid powertrain of the new energy vehicle, the internal and external component modes of the engine are optimized to decouple the crankshaft system modes within the engine. Specific optimization schemes are not elaborated here, as they vary depending on the powertrain design.

[0085] In summary, this invention proposes a method and standard for evaluating half-order vibration energy, providing an evaluation basis for early-stage forward simulation. For the industry-wide challenge of half-order impact in hybrid vehicles, it enables early-stage forward simulation and evaluation, allowing for hardware optimization and modification without requiring a final hardware design, thus avoiding material waste, saving project development costs, and conserving valuable project development time.

[0086] Please refer to Figure 2 The figure shows a vibration energy analysis and evaluation system for a new energy vehicle powertrain according to a second embodiment of the present invention, comprising:

[0087] Acquisition module 11: used to acquire the powertrain digital model of the new energy vehicle, and acquire the first material information of each component in the powertrain digital model corresponding to the engine origin, and the second material information of each component in the powertrain digital model itself;

[0088] The components in the powertrain digital model include the engine, suspension, hybrid transmission, dual-mass flywheel, and exhaust hot end; the first material information includes the center of mass and inertia, and the second material information includes the stiffness and damping of the suspension, the inertia of the dual-mass flywheel, the spring ratio of the dual-mass flywheel, the frequency of the front shock absorber pulley of the engine, and the cylinder pressure curve data of the engine under typical steady-state conditions;

[0089] Module 12: Used to establish a mesh and finite element model based on the first material information and the second material information;

[0090] Excitation module 13: used to reduce the finite element model and input the cylinder pressure excitation under steady-state conditions into the finite element model to obtain an adaptive dynamic model;

[0091] Processing module 14: used to solve the adaptive dynamics model, obtain acceleration data of the engine cylinder block surface and the active suspension end, and post-process the acceleration data to obtain post-processed time domain data;

[0092] Judgment module 15: used to determine whether the half-order vibration energy of the engine meets the acceptance limit based on the post-processed time domain data;

[0093] The judgment module is specifically used for:

[0094] Calculate the root mean square value of the total vibration energy of all cylinders in the engine in one complete cycle, and calculate the root mean square value of the individual vibration energy of each cylinder in the engine during the ignition cycle.

[0095] The average root mean square value of the total vibration energy of each cylinder is compared with the average root mean square value of the individual vibration energy to obtain the acceptance limit and determine whether the half-order vibration energy of the engine is qualified.

[0096] The specific steps for calculating the vibration energy value of each cylinder block within the entire engine during the ignition cycle include:

[0097] The post-processed time-domain data is subjected to bandpass filtering to obtain filtered time-domain data. The frequency of the bandpass filtering is 200Hz~800Hz.

[0098] The filtered time-domain data of all cylinders in the engine in one complete cycle is obtained, and the filtered time-domain data of each cylinder in the engine in the ignition cycle is obtained.

[0099] Obtain the crankshaft rotation angle data within the engine body at the calibrated angle;

[0100] The acquired crankshaft angle data is divided equally into several crankshaft angle components, and the number of crankshaft angle components is the same as the number of cylinder blocks.

[0101] Each crankshaft angle component is correlated with the ignition cycle of each cylinder block, and the root mean square value of the single vibration energy of each cylinder block in the filtered time domain data within the ignition cycle is calculated.

[0102] Calculate the overall average root mean square value of the vibration energy of the filtered time-domain data for all cylinders within one complete cycle;

[0103] The specific steps for comparing the average root mean square value of the total vibration energy of each cylinder block with the average root mean square value of the individual vibration energy to obtain the acceptance limit and determine whether the half-order vibration energy of the entire engine is qualified include:

[0104] A comparison formula is created by substituting the average root mean square value of the total vibration energy and the average root mean square value of the individual vibration energy into the comparison formula to obtain the size ratio value.

[0105] The size ratio values ​​in the database are processed and compared to determine the acceptable limit.

[0106] Engines whose size ratio exceeds the acceptance limit are considered to have unacceptable half-order vibration energy.

[0107] Optimization module 16: used to optimize engines that do not meet the acceptance limits;

[0108] The optimization module is specifically used for:

[0109] Based on the actual situation of the hybrid powertrain of the new energy vehicle, the internal and external component modes of the engine are optimized to decouple the crankshaft system mode within the engine.

[0110] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0111] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for analyzing and evaluating the vibration energy of a new energy vehicle powertrain, characterized in that, Includes the following steps: Obtain the powertrain digital model of the new energy vehicle, and obtain the first material information of each component in the powertrain digital model corresponding to the engine origin and the second material information of each component in the powertrain digital model itself; Based on the first material information and the second material information, a mesh and finite element model are established; The finite element model is reduced in size, and cylinder pressure excitation under steady-state conditions is input into the finite element model to obtain an adaptive dynamic model; Solve the adaptive dynamics model to obtain acceleration data of the engine cylinder block surface and the active suspension end, and post-process the acceleration data to obtain post-processed time domain data. Based on the post-processed time-domain data, it is determined whether the half-order vibration energy of the engine meets the acceptance limit. Optimize engines that do not meet the acceptance limits; The specific steps for determining whether the engine's half-order vibration energy meets the acceptance limit based on the post-processed time-domain data include: Calculate the root mean square value of the total vibration energy of all cylinders in the engine in one complete cycle, and calculate the root mean square value of the individual vibration energy of each cylinder in the engine during the ignition cycle. The root mean square value of the total vibration energy is compared with the root mean square value of the individual vibration energy to obtain the acceptance limit, and to determine whether the half-order vibration energy of the engine is qualified. The specific steps for calculating the root mean square value of the total vibration energy of all cylinders in the engine over a complete cycle, and for calculating the root mean square value of the individual vibration energy of each cylinder in the engine during an ignition cycle, include: The post-processed time-domain data is subjected to bandpass filtering to obtain filtered time-domain data. The frequency of the bandpass filtering is 200Hz~800Hz. The filtered time-domain data of all cylinders in the engine in one complete cycle is obtained, and the filtered time-domain data of each cylinder in the engine in the ignition cycle is obtained. Obtain the crankshaft rotation angle data of the calibrated angle within the engine; The acquired crankshaft angle data is divided equally into several crankshaft angle components, and the number of crankshaft angle components is the same as the number of cylinder blocks. Each crankshaft angle component is correlated with the ignition cycle of each cylinder block, and the root mean square value of the filtered time-domain data of each cylinder block within the ignition cycle of that cylinder is calculated as the root mean square value of the single vibration energy. The root mean square value of the filtered time-domain data of all cylinders within a complete cycle is calculated as the root mean square value of the overall vibration energy; the start time of the complete cycle is the compression bottom dead center of the first cylinder, and the end time of the complete cycle is the power bottom dead center of the last cylinder.

2. The method for analyzing and evaluating the vibration energy of a new energy vehicle powertrain according to claim 1, characterized in that, The components in the powertrain digital model include the engine, suspension, hybrid transmission, dual-mass flywheel, and exhaust hot end.

3. The method for analyzing and evaluating the vibration energy of a new energy vehicle powertrain according to claim 2, characterized in that, The first material information includes the center of mass and moment of inertia, and the second material information includes the stiffness and damping of the suspension, the moment of inertia of the dual-mass flywheel, the spring ratio of the dual-mass flywheel, the frequency of the front damping pulley of the engine, and the cylinder pressure curve data of the engine under typical steady-state conditions.

4. The method for vibration energy analysis and evaluation of new energy vehicle powertrains according to claim 1, characterized in that, The specific steps for comparing the total root mean square value of vibration energy with the root mean square value of individual vibration energy to obtain an acceptance limit and determining whether the half-order vibration energy of the entire engine is qualified include: A comparison formula is created by substituting the root mean square value of the total vibration energy and the root mean square value of the individual vibration energy into the comparison formula to obtain the size ratio value; The size ratio values ​​in the database are processed and compared to determine the acceptable limit. Engines whose size ratio exceeds the acceptance limit are considered to have unacceptable half-order vibration energy.

5. The method for vibration energy analysis and evaluation of new energy vehicle powertrains according to claim 4, characterized in that, The specific steps for optimizing engines that do not meet the acceptance limits include: Based on the actual situation of the hybrid powertrain of the new energy vehicle, the internal and external component modes of the engine are optimized to decouple the crankshaft system mode within the engine.

6. A vibration energy analysis and evaluation system for a new energy vehicle powertrain, characterized in that, include: Acquisition module: used to acquire the powertrain digital model of new energy vehicles, and to acquire the first material information of each component in the powertrain digital model corresponding to the engine origin and the second material information of each component in the powertrain digital model itself; The module for building a mesh and a finite element model is used to build the mesh and the finite element model based on the first material information and the second material information. Excitation module: used to reduce the finite element model and input the cylinder pressure excitation under steady-state conditions into the finite element model to obtain an adaptive dynamic model; Processing module: used to solve the adaptive dynamics model, obtain acceleration data of the engine cylinder block surface and the active suspension end, and post-process the acceleration data to obtain post-processed time domain data; Judgment module: used to determine whether the half-order vibration energy of the engine meets the acceptance limit based on the post-processed time-domain data; Optimization module: used to optimize engines that do not meet the acceptance limits; The judgment module is specifically used for: Calculate the root mean square value of the total vibration energy of all cylinders in the engine in one complete cycle, and calculate the root mean square value of the individual vibration energy of each cylinder in the engine during the ignition cycle. The root mean square value of the total vibration energy is compared with the root mean square value of the individual vibration energy to obtain the acceptance limit, and to determine whether the half-order vibration energy of the engine is qualified. The specific steps for calculating the root mean square value of the total vibration energy of all cylinders in the engine over a complete cycle, and for calculating the root mean square value of the individual vibration energy of each cylinder in the engine during an ignition cycle, include: The post-processed time-domain data is subjected to bandpass filtering to obtain filtered time-domain data. The frequency of the bandpass filtering is 200Hz~800Hz. The filtered time-domain data of all cylinders in the engine in one complete cycle is obtained, and the filtered time-domain data of each cylinder in the engine in the ignition cycle is obtained. Obtain the crankshaft rotation angle data of the calibrated angle within the engine; The acquired crankshaft angle data is divided equally into several crankshaft angle components, and the number of crankshaft angle components is the same as the number of cylinder blocks. Each crankshaft angle component is correlated with the ignition cycle of each cylinder block, and the root mean square value of the filtered time-domain data of each cylinder block within the ignition cycle of that cylinder is calculated as the root mean square value of the single vibration energy. The root mean square value of the filtered time-domain data of all cylinders within a complete cycle is calculated as the root mean square value of the overall vibration energy; the start time of the complete cycle is the compression bottom dead center of the first cylinder, and the end time of the complete cycle is the power bottom dead center of the last cylinder.

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