Hybrid system powertrain durability bench test and evaluation method

Abstract

The application discloses a hybrid power system power assembly durability bench test and evaluation method, and belongs to the technical field of hybrid power system testing. The method comprises the following steps: obtaining real-time working condition parameters of the hybrid power system under bench operation and establishing a power assembly transient response sequence; configuring a cyclic impact profile containing a torque step interval, a rotating speed sweep interval and a power constant interval according to the response sequence; determining a profile characteristic identifier, including a dominant damage interval, a cumulative damage interval and a coupling interference interval; selecting a sensitive control window of a bench control parameter by using the dominant damage interval and the cumulative damage interval, performing time domain alignment analysis of the control parameter and the measured strain response; after establishing damage accumulation constraints of key components of the power assembly, performing multi-stage load progressive application and completing durability equivalent evaluation. The method can more truly reproduce the multi-working condition coupling transient load characteristics of the hybrid power system, and improve the matching degree of durability evaluation and complex damage evolution characteristics.

Description

Technical Field

[0001] This invention relates to the field of hybrid power system testing technology, specifically to a bench test and evaluation method for the durability of hybrid powertrain systems. Background Technology

[0002] In bench durability testing, hybrid powertrain systems need to obtain evaluation results equivalent to those under real-world vehicle operating conditions. Current technologies typically construct durability test profiles using standard regulatory conditions or simplified cycles extracted from single torque and speed parameters. These conditions struggle to simultaneously reproduce the transient characteristics unique to hybrid systems, such as sudden torque changes, wide speed sweep frequency variations, and continuous power output. During operation, the torque of the engine and motor frequently switches, and changes in drive mode generate dramatic torque steps. The impact energy triggered by these steps is a significant source of damage to components such as gears and splines. Simultaneously, the powertrain undergoes a wide range of speed sweep frequency changes during acceleration and deceleration, easily inducing resonance in the housing and shaft system, leading to accumulated vibration fatigue. During high-speed cruising and stable power output, minute speed and torque fluctuations generate continuous alternating loads in the coupling mechanism, causing fretting wear and interface slippage damage. The three damage mechanisms mentioned above act in combination during the same driving cycle. The existing cross-sectional construction method of bench testing fails to divide these three mechanisms into specific intervals and convert energy equivalents, resulting in a deviation between the bench evaluation results and the actual service durability.

[0003] In damage accumulation calculation and load application control, conventional practices are based on constant amplitude or simple block spectrum loading throughout the entire lifespan, without distinguishing the load characteristics differences in different damage-dominant intervals. Dyne gauges inherently exhibit response delays and amplitude attenuation during command tracking. When load commands change drastically within transient intervals, significant phase lag and amplitude deviation occur between the actual torque and speed applied to the powertrain and the target command. This deviation prevents the measured strain response in torque step intervals and speed sweep intervals from precisely corresponding to the target control parameters in time, directly affecting the accuracy of calculating damage increments in critical components. Therefore, establishing a durability assessment method that can automatically identify dominant damage periods from operational data and perform time-domain compensation and progressive loading of control parameters has become a pressing issue. Summary of the Invention

[0004] This invention provides a bench test and evaluation method for the durability of a hybrid powertrain, which solves the problem that existing test profiles cannot simultaneously reflect the multi-source transient characteristics of torque step impact, speed sweep frequency cumulative vibration and power continuous stability coupling damage of a hybrid powertrain, as well as the durability evaluation deviation caused by the mismatch between control parameters and measured strain in the key damage range due to dynamometer response lag and amplitude attenuation.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a bench test and evaluation method for the durability of a hybrid powertrain, characterized in that the method includes: Real-time operating parameters of the hybrid power system under test are acquired, and a powertrain transient response sequence corresponding to the load spectrum of the test dynamometer is established based on the real-time operating parameters. A cyclic impact profile for durability testing is configured based on the powertrain transient response sequence, the cyclic impact profile including a torque step interval, a speed sweep interval, and a constant power interval. Profile feature identifiers in the cyclic impact profile are determined, including a dominant damage interval, a cumulative damage interval, and a coupling interference interval. After selecting a sensitive control window for the test control parameters using the dominant damage interval and the cumulative damage interval, a time-domain alignment analysis of the control parameters and the measured strain response within the sensitive control window is performed. After establishing damage accumulation constraints for key powertrain components based on the results of the time-domain alignment analysis, a multi-level progressive load application is performed under the cyclic impact profile, and the measured data from the multi-level progressive load application is used to complete the powertrain durability equivalent assessment.

[0006] Preferably, the step of acquiring the real-time operating parameters of the hybrid power system under test operation and establishing a powertrain transient response sequence corresponding to the load spectrum of the test dynamometer based on the real-time operating parameters includes: synchronously capturing the engine output shaft torque, motor output shaft speed, and vibration acceleration of the power coupling device housing through a test data acquisition system as the real-time operating parameters; performing timestamp alignment processing on the real-time operating parameters to obtain a set of synchronous time-series parameters; performing a sliding window Fourier transform on the set of synchronous time-series parameters to extract the fundamental frequency amplitude and second harmonic distortion rate within each window to generate frequency domain feature parameters; and mapping the frequency domain feature parameters according to the time series marking of the dynamometer load spectrum to establish the powertrain transient response sequence.

[0007] Preferably, the cyclic impact profile for durability testing is configured based on the powertrain transient response sequence. The cyclic impact profile includes a torque step interval, a speed sweep interval, and a power constant interval, comprising: extracting the start and end times of torque change rate exceeding a preset change rate threshold from the powertrain transient response sequence to define the torque step interval; extracting continuous periods of monotonically increasing or decreasing speed from the powertrain transient response sequence to define the speed sweep interval; extracting stable periods of power fluctuation amplitude maintained within a percentage of rated power from the powertrain transient response sequence to define the power constant interval; and connecting the torque step interval, the speed sweep interval, and the power constant interval in chronological order to generate the cyclic impact profile.

[0008] Preferably, determining the profile feature identifier in the cyclic impact profile, wherein the profile feature identifier includes a dominant damage interval, a cumulative damage interval, and a coupled interference interval, includes: calculating the cumulative torque impact energy value of each sampling point within the torque step interval, and selecting the continuous time period with the largest cumulative torque impact energy value as the dominant damage interval; calculating the rotational speed cycle frequency of each sampling point within the rotational speed sweep interval, and selecting the continuous time period where the rotational speed cycle frequency exceeds the resonance frequency threshold as the cumulative damage interval; calculating the power fluctuation integral value of each sampling point within the constant power interval, and selecting the continuous time period where the power fluctuation integral value exceeds the fluctuation integral threshold as the coupled interference interval; and outputting the dominant damage interval, the cumulative damage interval, and the coupled interference interval as the profile feature identifier.

[0009] Preferably, after selecting the sensitive control window for the test bench control parameters using the dominant damage interval and the cumulative damage interval, performing time-domain alignment analysis of the control parameters and measured strain response within the sensitive control window includes: extracting the torque command sequence and measured torque response sequence of the test bench dynamometer within the dominant damage interval, and calculating the phase lag between the torque command sequence and the measured torque response sequence; extracting the speed command sequence and measured speed response sequence of the test bench dynamometer within the cumulative damage interval, and calculating the amplitude attenuation rate between the speed command sequence and the measured speed response sequence; generating time-domain alignment correction coefficients based on the phase lag and the amplitude attenuation rate, and using the time-domain alignment correction coefficients to perform time-series shifting and amplitude compensation on the control parameters; and matching the time-series shifted and amplitude-compensated control parameters with the measured strain response point by point to complete the time-domain alignment analysis.

[0010] Preferably, after establishing the damage accumulation constraint of the key powertrain components based on the time-domain alignment analysis results, the multi-level progressive load application under the cyclic impact profile includes: extracting the strain peak sequence of the power coupling device housing and the torque fluctuation sequence of the engine crankshaft from the time-domain alignment analysis results; calculating the damage increment of the key components under each cyclic impact profile based on the strain peak sequence and the torque fluctuation sequence; summing the damage increments and generating a load switching identifier when the cumulative damage value reaches a preset damage threshold; increasing the load torque of the current cyclic impact profile by one step according to the load switching identifier to generate the next level cyclic impact profile, thus completing the multi-level progressive load application.

[0011] Preferably, the step of using the measured data from the progressively applied multi-level load to complete the powertrain durability equivalent assessment includes: collecting remaining life monitoring data of key components at each load level during the progressively applied multi-level load process; marking the remaining life monitoring data with load level sequences to form a life decay sequence indexed by load level; calculating the decay slope between adjacent load levels in the life decay sequence to obtain a set of decay slopes for each load level interval; determining the life decay inflection point load level based on the set of decay slopes, and using the measured data corresponding to the life decay inflection point load level as the benchmark output for the durability equivalent assessment.

[0012] Preferably, the step of synchronously capturing the engine output shaft torque, motor output shaft speed, and vibration acceleration of the power coupling device housing using a benchtop data acquisition system as the real-time operating parameters includes: installing a first torque flange at the engine output shaft end and synchronously acquiring the engine output shaft torque at a first sampling frequency; installing a second torque flange at the motor output shaft end and synchronously acquiring the motor output shaft speed at a second sampling frequency; installing piezoelectric accelerometers in three orthogonal directions on the surface of the power coupling device housing and synchronously acquiring the three orthogonal components of the vibration acceleration at a third sampling frequency; and synchronously latching the engine output shaft torque, motor output shaft speed, and the three orthogonal components of the vibration acceleration using a unified clock source to generate the real-time operating parameters.

[0013] Preferably, the step of extracting the torque command sequence and the measured torque response sequence of the dynamometer within the dominant damage range, and calculating the phase lag between the torque command sequence and the measured torque response sequence, includes: performing rising edge zero-crossing detection on the torque command sequence and the measured torque response sequence respectively to obtain a command rising edge time set and a response rising edge time set; performing nearest neighbor matching on the command rising edge time set and the response rising edge time set, and calculating the time difference of each matching pair; performing median filtering on all the time differences, filtering out outliers, and then arithmetically averaging the remaining differences to obtain the phase lag.

[0014] Preferably, the cumulative value of torque impact energy is the integral of the square of the difference between the instantaneous torque value at each sampling point and the reference torque over time.

[0015] This invention provides a bench test and evaluation method for the durability of a hybrid powertrain. By collecting real-time operating parameters of the hybrid system during bench operation, a transient response sequence of the powertrain corresponding to the load spectrum of the bench dynamometer is established. Based on this, a cyclic impact profile including torque step intervals, speed sweep intervals, and constant power intervals is configured to realistically simulate the composite load characteristics of the powertrain under transient, alternating, and continuous operating conditions.

[0016] As a technical solution of the present invention, profile feature identifiers are determined from the transient response sequence of the powertrain. These profile feature identifiers include a dominant damage region, a cumulative damage region, and a coupled interference region. The dominant damage region characterizes the area where the main impact energy is concentrated due to sudden torque changes; the cumulative damage region reflects the frequency of fatigue damage caused by cyclical speed changes; and the coupled interference region reflects the system interference behavior caused by electromechanical coupling under stable power conditions. By separating and identifying these three types of feature regions, the originally mixed load damage mechanisms can be distinguished, thereby improving the targeting of subsequent damage assessments.

[0017] Preferably, a sensitive control window for the test bench control parameters is selected using the dominant damage range and the cumulative damage range. Within this window, a time-domain alignment analysis is performed between the control parameters and the measured strain response. This analysis generates time-domain alignment correction coefficients based on the phase lag between the dynamometer torque command sequence and the measured torque response sequence, as well as the amplitude attenuation rate between the speed command sequence and the measured speed response sequence, to perform time-series shifting and amplitude compensation on the control parameters. This process eliminates the control-response mismatch problem caused by signal transmission delay and dynamic response attenuation, making the determination of damage accumulation constraints more accurate.

[0018] Based on the time-domain alignment analysis results, damage accumulation constraints are established for key powertrain components, and under these constraints, multi-level progressive load application using cyclic impact profiles is executed. During the multi-level progressive load application process, the damage increment under each impact profile is calculated based on the strain peak sequence and torque fluctuation sequence. When the cumulative damage reaches a preset damage threshold, a load switching indicator is generated, and the load torque is progressively increased to generate the next level of cyclic impact profile. This multi-level progressive approach can effectively constrain the damage application boundary while accelerating the assessment, avoiding the introduction of atypical failure modes caused by sudden load changes.

[0019] This method utilizes measured data from progressively applied multi-level loads to perform a durability equivalent assessment of the powertrain. Specifically, it collects remaining life monitoring data of key components at each load level and labels the load level sequence to form a life decay sequence. Then, it calculates the decay slope set between adjacent load levels, using the measured data corresponding to the load level at the life decay inflection point as the benchmark output for durability equivalent assessment. This method effectively maps the complex multi-level load process to a single equivalent life benchmark, preserving the cumulative effect of multi-level loads while providing a normalized evaluation scale for comparing the durability of different hybrid powertrain systems.

[0020] As a preferred technical solution of the present invention, real-time operating parameters are obtained by installing torque flanges at the engine output shaft end and the motor output shaft end respectively, and synchronously acquiring the engine output shaft torque and motor output shaft speed at different sampling frequencies. Piezoelectric accelerometers are installed on the surface of the power coupling device housing in three orthogonal directions to synchronously acquire the three orthogonal components of vibration acceleration. The above multi-source data are synchronously latched using a unified clock source to ensure strict synchronization of each parameter in the time dimension, providing a highly reliable data foundation for establishing the transient response sequence. In conjunction with this, within the dominant damage interval, the time difference between the torque command and response is calculated through rising edge zero-crossing detection and nearest neighbor matching, and the phase lag is obtained through median filtering and arithmetic averaging, thereby accurately quantifying the dynamic delay of the control link and further improving the robustness of the time-domain alignment analysis.

[0021] By organically combining the above methods, this invention can perform structural chemical condition analysis and damage feature decoupling of the hybrid powertrain based on actual operating condition response. It achieves progressive damage accumulation constraints by relying on precise time-domain alignment of the sensitive control window, ultimately completing the durability equivalent assessment. This method significantly improves the accuracy of bench testing in reproducing actual road loads, shortens the durability development cycle, and provides a quantitative basis for powertrain life prediction and structural optimization design.

[0022] The technical effects and advantages provided by the present invention in the above technical solution are as follows: The torque step interval is defined by extracting the start and end times when the torque rate of change exceeds a preset threshold from the powertrain transient response sequence; the speed sweep interval is defined by extracting continuous periods of monotonically increasing or decreasing speed; and the power constant interval is defined by extracting stable periods where the power fluctuation amplitude remains within the rated power percentage. These three intervals are then connected sequentially to generate a cyclic impact profile. This profile construction method allows a single test cycle to simultaneously include the impact load generated by drive mode switching, the broadband vibration excitation during acceleration and deceleration, and the micro-fluctuation load under continuous power output. This enables a comprehensive simulation of multiple damage mechanisms in the hybrid powertrain within a continuous test cycle, ensuring that the load input characteristics of the bench durability test are highly consistent with the torque transients, sweep frequency excitations, and continuous power coupling damage characteristics during actual vehicle operation. This improves the mapping ability of the equivalent evaluation results to the actual vehicle durability performance.

[0023] The cumulative torque impact energy at each sampling point within the torque step interval is calculated, and the continuous time period with the largest cumulative energy value is selected as the dominant damage interval. The rotational speed cycle frequency at each sampling point within the speed sweep interval is calculated, and the continuous time period exceeding the resonance frequency threshold is selected as the cumulative damage interval. The power fluctuation integral value at each sampling point within the constant power interval is calculated, and the continuous time period exceeding the fluctuation integral threshold is selected as the coupling interference interval. Within the dominant damage interval, the torque command sequence and measured torque response sequence of the dynamometer are extracted to calculate the phase lag. Within the cumulative damage interval, the speed command sequence and measured speed response sequence are extracted to calculate the amplitude attenuation rate. Based on the phase lag and amplitude attenuation rate, a time-domain alignment correction coefficient is generated. After time-series shifting and amplitude compensation of the control parameters, they are matched with the measured strain response point-by-point. By identifying and separating the time intervals where different damage mechanisms play a dominant role, and specifically calculating and compensating for the dynamometer's tracking error within each interval, the time misalignment and amplitude deviation between command and response in the rapid torque change channel and the high-frequency speed change channel are eliminated, ensuring precise synchronization between the applied load and the actual strain history of the component within these critical damage windows. Subsequently, based on the compensated strain and torque fluctuations, the damage increment under each cyclic impact profile is calculated. When the cumulative damage value reaches a preset damage threshold, a load switching indicator is generated. The load torque of the current cyclic impact profile is increased by one step to generate the next level of cyclic impact profile. Finally, the remaining life monitoring data under each load level during the multi-level load progression process is collected, and the measured data corresponding to the life decay inflection point load level is used as the benchmark output for durability equivalent assessment. This progressive loading strategy gradually approaches the inflection region of component damage acceleration and uses inflection point level data to calibrate the equivalent life, enabling the assessment results to capture the damage acceleration characteristics of the powertrain under extreme conditions, rather than just extrapolating calculations based on linear accumulation of low loads. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0025] Figure 1 This is a flowchart of the bench test and evaluation method for the durability of hybrid powertrain systems; Figure 2 This is a flowchart for establishing the transient response sequence of the powertrain; Figure 3 This is a flowchart of time-domain alignment analysis. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] See Figure 1 This invention provides a bench test and evaluation method for the durability of a hybrid powertrain, comprising: acquiring real-time operating parameters of the hybrid powertrain under bench operation, and establishing a powertrain transient response sequence corresponding to the load spectrum of a bench dynamometer based on the real-time operating parameters; configuring a cyclic impact profile for durability testing based on the powertrain transient response sequence, the cyclic impact profile including a torque step interval, a speed sweep interval, and a power constant interval; determining profile feature identifiers in the cyclic impact profile, the profile feature identifiers including a dominant damage interval, a cumulative damage interval, and a coupling interference interval; selecting a sensitive control window for bench control parameters using the dominant damage interval and the cumulative damage interval, and performing a time-domain alignment analysis of the control parameters and the measured strain response within the sensitive control window; establishing damage accumulation constraints for key powertrain components based on the results of the time-domain alignment analysis, and performing multi-level progressive load application under the cyclic impact profile, and completing the powertrain durability equivalent evaluation using the measured data of the multi-level progressive load application.

[0028] In specific implementation, please refer to Figure 2The system synchronously captures the engine output shaft torque, motor output shaft speed, and vibration acceleration of the power coupling device housing using a benchtop data acquisition system, serving as real-time operating parameters. A first torque flange is installed at the engine output shaft end, with its measurement range selected to be 1.5 times the engine's maximum output torque. The first torque flange synchronously acquires the engine output shaft torque at a first sampling frequency, which is set to be at least 5 times the highest frequency component to be acquired. A second torque flange is installed at the motor output shaft end, synchronously acquiring the motor output shaft speed at a second sampling frequency, which is set to be 10 times the electrical frequency corresponding to the motor's highest speed. Piezoelectric accelerometers are installed in three orthogonal directions on the surface of the power coupling device housing. The range of the piezoelectric accelerometers is determined to be twice the estimated maximum vibration level of the power coupling device housing. The three orthogonal components of the vibration acceleration are synchronously acquired at a third sampling frequency, which is not less than 5 times the natural frequency of the power coupling device housing. The three orthogonal components of engine output shaft torque, motor output shaft speed and vibration acceleration are synchronously latched by a unified clock source to generate real-time operating parameters. The unified clock source adopts the internal high-precision crystal oscillator of the bench data acquisition system. The frequency stability of the crystal oscillator is not less than ±1ppm. Synchronous latching is achieved by hardware triggering signals to latch data on the same clock edge for all channels.

[0029] Real-time operating parameters are timestamped to obtain a synchronized timing parameter set. The timestamping process employs a linear interpolation resampling method, using the engine output shaft torque timestamp as the reference time series. Interpolation is performed on the three orthogonal components of the motor output shaft speed and vibration acceleration. The interpolated parameters have the same time interval and the same start and end points. During interpolation, if the timestamp of the original data point does not perfectly match the time point of the reference time series, the interpolation point value is calculated using the values ​​of two adjacent sampling points from the original data point, proportional to the time interval.

[0030] A sliding window Fourier transform is performed on the synchronization timing parameter set. The length of the sliding window is selected as an integer multiple of one revolution cycle of the rotating machinery, and the sliding step size is set to half the window length. A sliding window Fourier transform is performed on the data of each channel in the synchronization timing parameter set. Within each window, the amplitude spectrum after the Fourier transform is calculated, and the amplitude corresponding to the fundamental frequency is extracted from the amplitude spectrum as the fundamental frequency amplitude. The fundamental frequency is determined as follows: based on the engine ignition frequency or the electric motor frequency under the current operating conditions as the reference fundamental frequency, the maximum amplitude within ±5% of this reference fundamental frequency is searched in the amplitude spectrum, and this maximum amplitude is taken as the fundamental frequency amplitude. Simultaneously, the amplitude at the second harmonic frequency (twice the fundamental frequency) is extracted from the amplitude spectrum, and the second harmonic distortion rate is calculated. The calculation formula is: ; in, Indicates the second harmonic distortion rate. This represents the amplitude corresponding to the second harmonic frequency extracted within the current sliding window. This represents the fundamental frequency amplitude extracted within the current sliding window. The fundamental frequency amplitude and second harmonic distortion rate of each window are combined to generate frequency domain characteristic parameters.

[0031] When establishing the powertrain transient response sequence, the frequency domain characteristic parameters are mapped according to the time series markers of the dynamometer load spectrum. The time series marker of the dynamometer load spectrum is a time vector, where each element represents a defined moment of the load spectrum. For the midpoint of time corresponding to each sliding window in the frequency domain characteristic parameters, the time marker closest to the midpoint is found in the time vector, and the frequency domain characteristic parameter corresponding to that time marker is assigned to the corresponding position in the powertrain transient response sequence. If the midpoints of multiple sliding windows are mapped to the same time marker, the arithmetic mean of the frequency domain characteristic parameters of these sliding windows is taken as the transient response value for that time marker. The powertrain transient response sequence established in this way corresponds strictly with the dynamometer load spectrum in time.

[0032] In practical implementation, the process of defining the torque step interval from the powertrain transient response sequence is as follows: Point-by-point differential calculation is performed on the torque parameters in the powertrain transient response sequence to obtain the torque change rate sequence. Torque change rate The calculation formula is: ; in, This represents the torque change rate, and u represents the sampling point number in the powertrain transient response sequence. The value of u ranges from 1 to an integer from the total number of sampling points in the powertrain transient response sequence minus 1. This represents the torque value corresponding to the (u+1)th sampling point. Δt represents the torque value corresponding to the u-th sampling point, and Δt represents the sampling time interval of the powertrain transient response sequence. The preset rate of change threshold is set to three times the effective value of the engine's maximum torque rate of change. The effective value of the engine's maximum torque rate of change is obtained by differentiating the torque conversion stage on the engine's external characteristic curve and taking the root mean square. The torque rate of change sequence is iterated. When the torque rate of change at a certain sampling point is detected to be greater than the preset rate of change threshold for the first time, the time corresponding to that sampling point is recorded as the start time of the torque step interval. From the start time onwards, the torque rate of change sequence continues to be iterated. When the torque rate of change falls back to below the preset rate of change threshold and remains below the preset rate of change threshold for a duration exceeding a preset multiple of the torque response delay time, the time corresponding to the sampling point that first falls below the preset rate of change threshold is taken as the end time of the torque step interval. The torque response delay time is determined based on the time from the issuance of the command to reaching 90% of the command value in the torque response calibration data of the dynamometer bench, and the preset multiple is set to 2 times.

[0033] Continuous periods of monotonically increasing or decreasing speed are extracted from the powertrain transient response sequence to define speed sweep intervals. First-order difference processing is performed on the speed parameters in the powertrain transient response sequence to obtain a speed difference sequence. If multiple consecutive positive difference values ​​appear in the speed difference sequence, the segment is determined to be a monotonically increasing period; if multiple consecutive negative difference values ​​appear, the segment is determined to be a monotonically decreasing period. The lower limit of the duration of monotonically increasing or decreasing speeds is set to half the shortest time required for the motor speed to increase from the minimum operating speed to the rated speed. This shortest time is calculated based on the motor's moment of inertia and maximum torque response characteristics. Scanning begins from the start of the powertrain transient response sequence. When the length of a period corresponding to consecutive positive difference values ​​exceeds the lower limit of the duration, that period is marked as a speed sweep interval; similarly, when the length of a period corresponding to consecutive negative difference values ​​exceeds the lower limit of the duration, that period is also marked as a speed sweep interval. If the interval between two monotonically changing periods is less than twice the speed sampling period, these two periods are merged into a single speed sweep interval.

[0034] The power constant interval is defined by extracting stable periods where the power fluctuation amplitude remains within a percentage of the rated power from the powertrain transient response sequence. The power fluctuation amplitude is obtained by calculating the absolute value of the difference between the instantaneous power and the rated power point by point, and then dividing by the rated power. The rated power percentage is set to 5%. The power fluctuation amplitude sequence is continuously evaluated; when the power fluctuation amplitude at multiple consecutive sampling points is less than 5%, and the length of this continuous period is not less than one-third of the powertrain thermal equilibrium time constant, this continuous period is defined as a power constant interval. The powertrain thermal equilibrium time constant is determined by the time constant during bench thermal equilibrium testing when the coolant temperature tends to stabilize.

[0035] All defined torque step intervals, speed sweep intervals, and constant power intervals are sorted according to their respective start times. Starting with the earliest interval, the sorted intervals are sequentially connected end-to-end, with the end time of the previous interval directly coinciding with the start time of the next interval, without inserting any transition intervals at the connection points, thus generating a cyclic impact profile. A complete cycle of the cyclic impact profile includes one iteration of each of the selected torque step intervals, speed sweep intervals, and constant power intervals, and the total duration of the cyclic impact profile is equal to the sum of the durations of all intervals.

[0036] In practical implementation, when calculating the cumulative torque impact energy at each sampling point within the torque step interval, the torque value at the start of the torque step interval is used as the reference torque. For each sampling point within the torque step interval, the instantaneous torque value corresponding to the sampling point is obtained, the difference between the instantaneous torque value and the reference torque is calculated, and the difference is squared to obtain the squared difference. The calculation of the cumulative torque impact energy uses a time-domain numerical integration method, with the integration time range from the start to the end of the torque step interval, and the integration step size being the sampling time interval of the powertrain transient response sequence. Cumulative Torque Impact Energy The expression is: ; in, This represents the cumulative value of torque impact energy, with dimensions of ; p represents the index of the sampling point within the torque step interval, and the value of p is an integer from 1 to Q-1 (i.e., representing the p-th time interval), Q represents the total number of sampling points contained in the torque step interval; T(p) represents the instantaneous torque value corresponding to the p-th sampling point within the torque step interval; T(p+1) represents the instantaneous torque value corresponding to the (p+1)-th sampling point within the torque step interval; This represents the reference torque corresponding to the starting moment of the torque step interval; This represents the sampling time interval of the powertrain transient response sequence. (Note: When Q=1, the duration of this interval is 0.) Recorded as 0)

[0037] In practice, after obtaining the cumulative torque impact energy values ​​of all sampling points within the torque step interval, the continuous time period with the largest cumulative torque impact energy value is selected as the dominant damage interval. Specifically, the torque step interval is divided into multiple adjacent candidate continuous time periods in chronological order. The length of each candidate continuous time period is set to 30% of the total duration of the torque step interval, and the overlap rate between adjacent candidate continuous time periods is set to 50%. The sum of the cumulative torque impact energy values ​​of all sampling points within each candidate continuous time period is calculated, and the candidate continuous time period with the largest sum of cumulative torque impact energy values ​​is determined as the candidate dominant time period. Based on the candidate dominant time period, one sampling point is extended in both directions before and after the candidate dominant time period to form an extended time period. The sum of the cumulative torque impact energy values ​​of the extended time period is calculated. If the sum of the cumulative torque impact energy values ​​of the extended time period is greater than the sum of the cumulative torque impact energy values ​​of the candidate dominant time period, the extended time period is used as a new candidate dominant time period and the extension continues until the sum of the cumulative torque impact energy values ​​no longer increases. The final extended continuous time period is then used as the dominant damage interval.

[0038] In practical implementation, the rotational speed cycle frequency at each sampling point within the rotational speed sweep interval is calculated. A Hilbert transform is performed on the rotational speed parameter within the sweep interval to obtain the phase function of the analytic signal. The instantaneous frequency is obtained by time differentiation of the phase function, and then divided by 60 to obtain the rotational speed cycle frequency in Hertz. The resonance frequency threshold is determined based on the natural frequency characteristics of the power coupling device housing. A hammer impact mode test is performed on the power coupling device housing to obtain its first and second natural bending frequencies. The resonance frequency threshold is set to 80% of the first natural bending frequency. The rotational speed cycle frequency at each sampling point within the rotational speed sweep interval is traversed, and compared with the resonance frequency threshold. When multiple consecutive sampling points show rotational speed cycle frequencies greater than the resonance frequency threshold, the first sampling point that meets the condition is taken as the starting point, and the last sampling point that meets the condition is taken as the ending point. The continuous time period between the starting point and the ending point is considered a candidate cumulative time period. When multiple candidate cumulative time periods appear within the rotational speed sweep frequency range, the candidate cumulative time period with the longest duration is selected as the cumulative damage range.

[0039] In practice, the power fluctuation integral value is calculated for each sampling point within the constant power interval. The calculation method is as follows: using the power value at the beginning of the constant power interval as the reference power, for each sampling point within the constant power interval, the difference between the instantaneous power value and the reference power is calculated, and the absolute value is taken to obtain the instantaneous power fluctuation value. This instantaneous power fluctuation value is then cumulatively integrated over time using a composite trapezoidal rule, with the integration step size being the sampling time interval of the powertrain transient response sequence. The integration result is the power fluctuation integral value. The fluctuation integral threshold is set as follows: power fluctuation data of the hybrid power system under rated power conditions for 10 minutes during steady-state bench testing is obtained. The power fluctuation integral value is calculated from the power fluctuation data, and the 95th percentile of the power fluctuation integral value is taken as the fluctuation integral threshold. The power fluctuation integral values ​​of each sampling point within the constant power interval are iterated. When the power fluctuation integral values ​​of multiple consecutive sampling points are detected to exceed the fluctuation integral threshold, the first sampling point that exceeds the fluctuation integral threshold is taken as the starting point, and the last sampling point that exceeds the fluctuation integral threshold is taken as the ending point. The continuous time period between the starting point and the ending point is determined as the coupling interference interval.

[0040] In practice, after defining the dominant damage interval, cumulative damage interval, and coupled interference interval, the start and end time information of the dominant damage interval, cumulative damage interval, and coupled interference interval are arranged in chronological order of their start times to form an interval identifier data group. This interval identifier data group is then output as the profile feature identifier. Each interval in the profile feature identifier contains three fields: interval type label, interval start time, and interval end time. The interval type label is distinguished by a numerical code: type label 1 corresponds to the dominant damage interval, type label 2 corresponds to the cumulative damage interval, and type label 3 corresponds to the coupled interference interval.

[0041] In specific implementation, please refer to Figure 3 Within the dominant damage range, the torque command sequence and measured torque response sequence of the dynamometer were extracted. The torque command sequence was directly read from the dynamometer's control system, and its timestamp was aligned with the start and end times of the dominant damage range. The measured torque response sequence was acquired using a torque sensor mounted on the dynamometer's output shaft, with the sensor's sampling frequency synchronized with the clock of the dynamometer's data acquisition system.

[0042] Zero-crossing detection of rising edges is performed on both the torque command sequence and the measured torque response sequence to obtain the command rising edge time set and the response rising edge time set. The zero-crossing detection process is as follows: the mean of the torque command sequence is subtracted from the value of each sample point in the torque command sequence to obtain a mean-reduced command sequence. In the mean-reduced command sequence, starting from the second sample point, the sequence iterates until the value of the m-th sample point is less than zero and the value of the (m+1)-th sample point is greater than or equal to zero. Then, the times corresponding to the m-th and (m+1)-th sample points are linearly interpolated to calculate the precise time of the zero-crossing point of the mean-reduced command sequence. This precise time of the zero-crossing point of the mean-reduced command sequence is added to the command rising edge time set as a command rising edge time. The same process is performed on the measured torque response sequence: the mean of the measured torque response sequence is subtracted from the value of each sample point in the measured torque response sequence to obtain a mean-reduced response sequence. Zero-crossing detection and linear interpolation are then performed on the mean-reduced response sequence to obtain the response rising edge time, which is added to the response rising edge time set.

[0043] Perform nearest neighbor matching on the instruction rising edge time set and the response rising edge time set. Starting from the first instruction rising edge time in the instruction rising edge time set, find the response rising edge time in the response rising edge time set with the smallest absolute value of the time difference with the instruction rising edge time. Combine the found instruction rising edge time and response rising edge time into a matching pair. Remove the matched instruction rising edge time and response rising edge time from the instruction rising edge time set and response rising edge time set respectively, and continue matching the remaining instruction rising edge time and response rising edge time until either the instruction rising edge time set or the response rising edge time set is empty. For each matching pair, calculate the time difference between the response rising edge time and the instruction rising edge time in the matching pair.

[0044] Median filtering is applied to all time differences, with a window length of 5. If the number of time differences within the filtering window is less than 5, the median of the actual number is used. The time differences within the filtering window are sorted by value, and the median value is taken as the median filtering result. This median filtering result replaces the time difference at the center of the window. After median filtering, the absolute deviation of all time differences from the median filtering result is calculated. Time differences with an absolute deviation greater than 3 times the median absolute deviation are marked as outliers. The median absolute deviation is the median of the absolute deviations of all time differences from the median filtering result. Outliers are removed from the time difference set, and the remaining time differences are arithmetically averaged. The result of this arithmetic mean is the phase lag.

[0045] Within the cumulative damage range, the speed command sequence and measured speed response sequence of the dynamometer were extracted. The speed command sequence was directly read from the dynamometer's control system, while the measured speed response sequence was acquired by a speed sensor mounted on the dynamometer's output shaft. The amplitude attenuation rate between the speed command sequence and the measured speed response sequence was calculated. Amplitude attenuation rate The calculation formula is: ; in, Indicates the amplitude attenuation rate. This represents the fundamental frequency amplitude of the speed command sequence within the cumulative damage interval. The fundamental frequency amplitude is obtained by performing a fast Fourier transform on the speed command sequence and then extracting the amplitude corresponding to the fundamental frequency of the speed command sequence. The fundamental frequency of the speed command sequence is the average frequency of change of the speed command sequence within the cumulative damage interval. This represents the fundamental frequency amplitude of the measured speed response sequence within the cumulative damage range. The fundamental frequency amplitude is obtained by performing a fast Fourier transform on the measured speed response sequence and then extracting the amplitude corresponding to the fundamental frequency of the measured speed response sequence. The fundamental frequency of the measured speed response sequence and the fundamental frequency of the speed command sequence are set to the same frequency value.

[0046] Time-domain alignment correction coefficients are generated based on phase lag and amplitude attenuation rate. These coefficients include timing shift correction coefficients and amplitude compensation correction coefficients. The timing shift correction coefficient is directly taken as the value of the phase lag, in seconds. The amplitude compensation correction coefficient is taken as the reciprocal of the amplitude attenuation rate, i.e., The method for time-domain alignment correction coefficients to perform time-series shifting and amplitude compensation of control parameters is as follows: the original control parameter sequence output by the dynamometer within the sensitive control window is shifted along the time axis by the duration corresponding to the time-series shift correction coefficient, with the shift direction opposite to the phase lag direction; then, the value of each sampling point in the shifted control parameter sequence is multiplied by the amplitude compensation correction coefficient to obtain the compensated control parameter sequence.

[0047] The time-shifted and amplitude-compensated control parameters are matched with the measured strain response point by point. The measured strain response is obtained by attaching strain gauges to key stress concentration areas of the dynamic coupling device shell and acquiring them using a dynamic strain gauge. The timestamps of the compensated control parameter sequence are aligned with the timestamps of the measured strain response. The alignment method is to use the timestamps of the compensated control parameter sequence as a reference and perform linear interpolation on the measured strain response, so that the measured strain response and the compensated control parameter sequence have a one-to-one correspondence of sampling points, thereby completing the time-domain alignment analysis.

[0048] In practice, the strain peak sequence of the power coupling device housing and the torque fluctuation sequence of the engine crankshaft are extracted from the time-domain alignment analysis results. The extraction method for the strain peak sequence of the power coupling device housing is as follows: The strain time history data collected from strain measurement points on the power coupling device housing in the time-domain alignment analysis results are searched using a peak detection algorithm. When the strain value of a certain sampling point is greater than the strain value of the previous sampling point and greater than the strain value of the next sampling point, this sampling point's strain value is taken as a strain peak. All detected strain peaks are arranged in chronological order to form a strain peak sequence. The extraction method for the torque fluctuation sequence of the engine crankshaft is as follows: Bandpass filtering is applied to the torque time history data of the engine crankshaft in the time-domain alignment analysis results. The passband frequency range of the bandpass filter is from 0.8 times to 1.2 times the engine ignition frequency. Each sampling point value in the filtered torque time history data is taken as a torque fluctuation value and arranged in chronological order to form a torque fluctuation sequence.

[0049] In practical implementation, the damage increment of key components under each cyclic impact profile is calculated based on the strain peak sequence and torque fluctuation sequence. Key components include the power coupling device housing and the engine crankshaft. For the power coupling device housing, the damage increment is calculated using the local stress-strain method. Each strain peak in the strain peak sequence is substituted into the cyclic stress-strain curve of the power coupling device housing material to obtain the corresponding stress amplitude. The Manson-Coffin formula is used to calculate the single-cycle damage corresponding to each strain peak. The single-cycle damages are accumulated to obtain the damage increment of the power coupling device housing under one cyclic impact profile. For the engine crankshaft, each torque fluctuation value in the torque fluctuation sequence is converted into the shear stress amplitude of the crankshaft's critical section. The conversion coefficient is obtained through finite element static analysis of the engine crankshaft. The shear stress amplitude is substituted into the SN curve expression of the engine crankshaft material to calculate the fatigue damage corresponding to each torque fluctuation value. The fatigue damages are accumulated to obtain the damage increment of the engine crankshaft under one cyclic impact profile. The total damage increment of the key components under one cyclic impact profile is taken as the larger value between the damage increment of the power coupling device housing and the damage increment of the engine crankshaft.

[0050] The damage increments are cumulatively summed, and a preset damage threshold is set. The cumulative summation method is as follows: starting from the first-level cyclic impact profile, the total damage increment calculated for each cyclic impact profile is added to the cumulative damage value of the previous level to obtain the current cumulative damage value. The cumulative damage value before the first-level cyclic impact profile is initialized to zero. The preset damage threshold is set based on the critical damage value corresponding to the design life of the key component. The critical damage value is set to 1.0, and the preset damage threshold is set to 80% of the critical damage value, i.e., 0.8. When the cumulative damage value reaches 0.8 or exceeds 0.8 for the first time, a load switching identifier is generated. The load switching identifier includes the load level number of the current cyclic impact profile and the current cumulative damage value.

[0051] Based on the load switching indicator, the load torque of the current cyclic impact profile is incremented by one step to generate the next-level cyclic impact profile, completing the multi-level progressive load application. The initial value of the load torque is 60% of the rated output torque of the hybrid power system, and the step size is set to 5% of the rated output torque of the hybrid power system. The step size is set based on ensuring that the number of progressive levels is no less than 3 while maintaining distinguishable load increments. The method for generating the next-level cyclic impact profile is as follows: keeping the time structure of the torque step interval, speed sweep interval, and power constant interval of the original cyclic impact profile unchanged, all torque values ​​in the original cyclic impact profile are uniformly multiplied by a progressive coefficient, which is the ratio of the incremented load torque to the original load torque.

[0052] During the progressive application of multi-level loads, residual life monitoring data of critical components at each load level are collected. The data collection method for critical component residual life monitoring is as follows: During the execution of the cyclic impact profile corresponding to each load level, after the cyclic impact profile is completed, non-destructive testing is used to detect cracks in the critical weld areas of the power coupling device housing, and the crack length is recorded; simultaneously, journal wear is measured on the engine crankshaft, and the wear depth is recorded. The crack length and wear depth values ​​are then linked to the corresponding load level number, establishing a correspondence between load levels and residual life monitoring data.

[0053] The remaining life monitoring data is labeled with load level sequences to form a life decay sequence indexed by load level. The load level sequence labeling method is as follows: all load levels are numbered in ascending order of load torque, starting from 1 and incrementing sequentially. The crack length and wear depth values ​​measured at each load level are filled into a data table indexed by the load level number. The crack length and wear depth values ​​are treated as two independent life decay sequences. The labeled crack length sequence and wear depth sequence each constitute a life decay sequence indexed by load level.

[0054] The attenuation slope between adjacent load levels is calculated for the lifetime decay sequence, resulting in a set of attenuation slopes for each load level interval. Taking the crack length sequence as an example, the attenuation slope... The calculation formula is: ; in, Let represent the attenuation slope, r represent the load level number, and the value of r ranges from 1 to an integer from the total number of load levels minus 1; L(r+1) represents the crack length value corresponding to the (r+1)th load level; L(r) represents the crack length value corresponding to the rth load level; F(r+1) represents the load torque value corresponding to the (r+1)th load level; and F(r) represents the load torque value corresponding to the rth load level. The above calculation is performed for each pair of adjacent load levels, and all the obtained attenuation slope values ​​constitute the crack length attenuation slope set. The attenuation slope of the wear depth sequence is calculated using the same method as that of the crack length sequence, resulting in the wear depth attenuation slope set.

[0055] The lifetime decay inflection point load level is determined based on the decay slope set. The decay slope values ​​in the crack length decay slope set are iterated. Starting from the second decay slope value, the ratio of each decay slope value to the previous decay slope value is calculated. When the ratio of a certain decay slope value to the previous decay slope value is found to be greater than 2, the higher-level load level corresponding to this decay slope value is determined as the crack length lifetime decay inflection point load level. The same detection process is performed on the wear depth decay slope set. The higher-level load level corresponding to the ratio of the decay slope value to the previous decay slope value being greater than 2 is determined as the wear depth lifetime decay inflection point load level. The load level that appears earlier between the crack length lifetime decay inflection point load level and the wear depth lifetime decay inflection point load level is taken as the final lifetime decay inflection point load level. The measured data corresponding to the lifetime decay inflection point load level is used as the benchmark output for durability equivalent evaluation. The measured data includes the crack length value, wear depth value, load torque value, and number of cyclic impact profile repetitions at the lifetime decay inflection point load level.

[0056] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A bench test and evaluation method for the durability of a hybrid powertrain, characterized in that, The method includes: The real-time operating parameters of the hybrid power system under test are obtained, and a powertrain transient response sequence corresponding to the load spectrum of the test dynamometer is established based on the real-time operating parameters. The cyclic impact profile for durability testing is configured based on the transient response sequence of the powertrain, and the cyclic impact profile includes a torque step range, a speed sweep range, and a power constant range. The profile feature identifiers in the cyclic impact profile are determined, and the profile feature identifiers include the dominant damage region, the cumulative damage region, and the coupled interference region; After selecting the sensitive control window of the test bench control parameters using the dominant damage range and the cumulative damage range, a time-domain alignment analysis of the control parameters and the measured strain response within the sensitive control window is performed. After establishing damage accumulation constraints for key powertrain components based on the results of the time-domain alignment analysis, multi-level progressive load application under the cyclic impact profile is performed, and the powertrain durability equivalent assessment is completed using the measured data from the multi-level progressive load application.

2. The method for bench testing and evaluation of the durability of a hybrid powertrain according to claim 1, characterized in that, The process of acquiring real-time operating parameters of the hybrid power system under test bench operation and establishing a powertrain transient response sequence corresponding to the load spectrum of the test bench dynamometer based on the real-time operating parameters includes: The engine output shaft torque, motor output shaft speed and power coupling device housing vibration acceleration are synchronously captured by the bench data acquisition system and used as the real-time operating parameters. The real-time operating parameters are timestamped to obtain a set of synchronous timing parameters; Perform a sliding window Fourier transform on the set of synchronous timing parameters, extract the fundamental frequency amplitude and second harmonic distortion rate in each window, and generate frequency domain feature parameters; The frequency domain characteristic parameters are mapped according to the time series label of the dynamometer load spectrum to establish the transient response sequence of the powertrain.

3. The method for bench testing and evaluation of the durability of a hybrid powertrain according to claim 1, characterized in that, The cyclic impact profile for durability testing is configured based on the transient response sequence of the powertrain. The cyclic impact profile includes a torque step range, a speed sweep range, and a constant power range, including: Extract the start and end times when the torque change rate exceeds a preset change rate threshold from the powertrain transient response sequence to define the torque step interval; Extract continuous periods of monotonically increasing or monotonically decreasing speed from the transient response sequence of the powertrain, and define the speed sweep interval; Extract stable periods in which the power fluctuation amplitude remains within the percentage of the rated power from the transient response sequence of the powertrain, and define the constant power range; The cyclic impact profile is generated by connecting the torque step interval, the speed sweep interval, and the power constant interval in chronological order.

4. The method for bench testing and evaluation of the durability of a hybrid powertrain according to claim 1, characterized in that, The step of determining the profile feature identifiers in the cyclic impact profile, wherein the profile feature identifiers include the dominant damage region, the cumulative damage region, and the coupled interference region, includes: Calculate the cumulative value of torque impact energy at each sampling point within the torque step interval, and select the continuous time period with the largest cumulative value of torque impact energy as the dominant damage interval. Calculate the rotational speed cycle frequency at each sampling point within the rotational speed sweep interval, and select the continuous time period in which the rotational speed cycle frequency exceeds the resonance frequency threshold as the cumulative damage interval; Calculate the power fluctuation integral value of each sampling point within the power constant interval, and select the continuous time period in which the power fluctuation integral value exceeds the fluctuation integral threshold as the coupling interference interval; The dominant damage region, the cumulative damage region, and the coupled interference region are output as the profile feature identifiers.

5. The method for bench testing and evaluation of the durability of a hybrid powertrain according to claim 1, characterized in that, After selecting the sensitive control window for the test bench control parameters using the dominant damage range and the cumulative damage range, the time-domain alignment analysis of the control parameters and the measured strain response within the sensitive control window is performed, including: Extract the torque command sequence and measured torque response sequence of the bench dynamometer within the dominant damage range, and calculate the phase lag between the torque command sequence and the measured torque response sequence. Within the cumulative damage range, extract the speed command sequence and the measured speed response sequence of the bench dynamometer, and calculate the amplitude attenuation rate between the speed command sequence and the measured speed response sequence. A time-domain alignment correction coefficient is generated based on the phase hysteresis and the amplitude attenuation rate. The time-domain alignment correction coefficient is then used to perform time-series shifting and amplitude compensation on the control parameters. The time-domain alignment analysis is completed by matching the control parameters after time-shifting and amplitude compensation with the measured strain response point by point.

6. The method for bench testing and evaluation of the durability of a hybrid powertrain according to claim 1, characterized in that, After establishing damage accumulation constraints for key powertrain components based on the time-domain alignment analysis results, the multi-level progressive load application under the cyclic impact profile is executed, including: The strain peak sequence of the power coupling device housing and the torque fluctuation sequence of the engine crankshaft are extracted from the time-domain alignment analysis results. The damage increment of the key components under each cyclic impact profile is calculated based on the strain peak sequence and the torque fluctuation sequence. The damage increments are summed cumulatively, and a load switching flag is generated when the cumulative damage value reaches a preset damage threshold. Based on the load switching identifier, the load torque of the current cyclic impact profile is increased by one step to generate the next level of cyclic impact profile, thus completing the multi-level progressive application of load.

7. The method for bench testing and evaluation of the durability of a hybrid powertrain according to claim 1, characterized in that, The process of using measured data from the progressively applied multi-level loads to complete the powertrain durability equivalent assessment includes: Collect monitoring data on the remaining life of key components at each load level during the multi-level load progressive application process; The remaining lifetime monitoring data is labeled with load-level sequences to form a lifetime decay sequence indexed by load level; The attenuation slope between adjacent load levels is calculated for the lifetime attenuation sequence to obtain the attenuation slope set for each load level interval; The lifetime decay inflection point load level is determined based on the decay slope set, and the measured data corresponding to the lifetime decay inflection point load level is used as the benchmark output for the durability equivalent assessment.

8. The method for bench testing and evaluation of the durability of a hybrid powertrain according to claim 2, characterized in that, The method of synchronously capturing the engine output shaft torque, motor output shaft speed, and vibration acceleration of the power coupling device housing through a bench data acquisition system as real-time operating parameters includes: A first torque flange is installed at the engine output shaft end, and the engine output shaft torque is synchronously acquired at a first sampling frequency. A second torque flange is installed at the motor output shaft end, and the motor output shaft speed is synchronously collected at a second sampling frequency; Piezoelectric accelerometers are installed in three orthogonal directions on the surface of the power coupling device housing, and the three orthogonal components of the vibration acceleration are collected synchronously at a third sampling frequency. The three orthogonal components of the engine output shaft torque, the motor output shaft speed, and the vibration acceleration are synchronously latched by a unified clock source to generate the real-time operating parameters.

9. The method for bench testing and evaluation of the durability of a hybrid powertrain according to claim 5, characterized in that, The step of extracting the torque command sequence and measured torque response sequence of the dynamometer within the dominant damage range, and calculating the phase lag between the torque command sequence and the measured torque response sequence, includes: Perform rising edge zero-crossing detection on the torque command sequence and the measured torque response sequence respectively to obtain the command rising edge time set and the response rising edge time set; Perform nearest neighbor matching on the set of rising edges of the instruction and the set of rising edges of the response, and calculate the time difference of each matching pair; Median filtering is applied to all the time differences to remove outliers, and the remaining differences are then averaged to obtain the phase lag.

10. The method for bench testing and evaluation of the durability of a hybrid powertrain according to claim 4, characterized in that, The cumulative value of torque impact energy is the integral of the square of the difference between the instantaneous torque value and the reference torque at each sampling point over time.

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