A Construction Method for the Acceleration Durability Test Specification of a Pure Electric Vehicle Powertrain

Abstract

A construction method for the acceleration durability test specification of the powertrain of a pure electric vehicle. The present invention relates to the technical field of pure electric vehicle testing, and solves the problem that the durability test method of the powertrain of existing traditional vehicles is continued to be used, which cannot truly reflect the actual usage of pure electric vehicle users, resulting in inaccurate test results. The construction method for the acceleration durability test specification of the powertrain of a pure electric vehicle includes: user data collection; data processing: including user load distribution calculation and positive and negative torque damage calculation; determination of user targets; extraction of user working conditions; determination of test field working conditions; equivalence between users and test fields; and formation of an acceleration test method. The present invention changes the subjective speculation test equivalence based on traditional vehicles in the past, and has positive significance in aspects such as the lightweight, endurance, and durability of electric vehicles.

Description

Technical Field

[0001] The present invention relates to the technical field of pure electric vehicle test technology, and particularly to the accelerating durability test technology of the powertrain of pure electric vehicles. Background Art

[0002] Due to the torque characteristics of the drive motor, the absence of a clutch, and structural features such as a single-stage reduction in pure electric vehicles, the load on the powertrain is very different from that of traditional vehicles. Specifically, it is manifested in aspects such as a large starting torque, high speed, and strong energy recovery. The load on the powertrain of pure electric vehicles is much greater than that of fuel vehicles, and its own structural characteristics cause the energy release of the powertrain to be very fast, without any buffer. Therefore, in the development process of pure electric vehicles, it is particularly important to verify the accelerating durability test of the vehicle powertrain.

[0003] Currently, the powertrain durability tests conducted on pure electric vehicles all adopt the durability test methods of traditional vehicles, performing working conditions such as acceleration, coasting, and braking on the test field in order to achieve the user's operating load. For example: Patent CN112924189A (publication date: February 27, 2013) provides a method for testing the durability of an automotive powertrain, using a bench device to test the relevant loads of the powertrain; Patent CN102944422A (publication date: June 8, 2021) provides a method for reproducing the fatigue of the driving load of an automotive powertrain, simulating and reproducing the load of a real vehicle indoors to assess the fatigue life of the automotive powertrain indoors; Patent CN111460370A (publication date: July 28, 2020) provides a method for correlating an automotive powertrain test field, analyzing the target program working conditions based on the structure of a traditional vehicle, and determining the durability specification of the power transmission system of the correlated test field according to the half-shaft torque, the three-axis accelerations of the two front wheel steering knuckles, and the three-axis acceleration of the transmission housing. However, the above technologies are all durability test methods for the powertrain of traditional fuel vehicles and are not applicable to the durability test methods of pure electric vehicles for the powertrain.

[0004] The differences between pure electric vehicles and traditional fuel-powered vehicles in terms of operating range, acceleration characteristics, and energy recovery dictate a completely different approach to test methodology development. If electric vehicles were tested using the same drivetrain durability test standards as traditional vehicles, there would be a significant difference in reverse load, reducing the load input to the reducer, drive shaft, and other transmission components by approximately 15%, directly impacting transmission component verification. Secondly, energy recovery is a crucial energy-saving metric for electric vehicles. During coasting and braking below 0.3g, the power battery enters a charging state. Using the same test conditions as traditional vehicles would significantly reduce energy recovery verification. Therefore, using the existing drivetrain durability test methods for traditional vehicles without considering factors such as pure electric vehicle user operating data, powertrain structural characteristics, and torque compliance would fail to truly reflect actual pure electric vehicle user experience, resulting in inaccurate test results. Summary of the Invention

[0005] In order to solve the above problems, the present invention proposes a method for constructing an accelerated endurance test specification for a pure electric vehicle transmission system.

[0006] The technical solutions of the present invention are as follows:

[0007] A method for constructing an accelerated durability test specification for a pure electric vehicle powertrain comprises the following steps:

[0008] Step 1: User data collection: Install the data collector on the vehicle under test, connect it to the vehicle's OBD to obtain power and CAN information, and then return it to the user. The user follows normal driving habits and usage characteristics. When the vehicle's ignition switch is turned on, the data collector automatically starts collecting data and automatically stops when the user turns off the ignition switch. Data is stored in the collector card as it is collected.

[0009] Step 2: Data processing: including user load distribution calculation and positive and negative torque damage calculation;

[0010] Step 3: Determine user goals;

[0011] Step 4: User working condition extraction: Put all users' load distributions together to form the user's overall working condition diagram. Draw 4 points of positive and negative torque on the diagram. The information of each point is torque and speed, which is the user's working condition.

[0012] Step 5: Determine the test field operating conditions: Determine the starting speed, ending speed, and starting and ending torque ranges for the eight operating conditions based on the characteristics of the points in the user operating condition map. The torque range is reflected during driving by the accelerator pedal opening.

[0013] Step 6: Equivalent of the user and the test site: After collecting the motor speed and torque through the working conditions of the test site, by optimizing the number of cycles of the matching working conditions, the damage cycle numbers of positive and negative torques are made consistent with the user's target.

[0014] Step 7: The working conditions and the number of cycles of the test site are divided into multiples of 10, and small cycle operations are carried out in sequence to form an accelerated test method.

[0015] Preferably, the distribution principle of the vehicle to be tested is as follows: In first-tier cities Shanghai and Shenzhen, in second-tier cities Nanjing, Chongqing, Hangzhou, Wuhan, Kunming, Changchun, and in third-tier cities Sanya and Xiamen, 10 users are determined in each city, including 6 operating vehicles and 4 private cars.

[0016] Preferably, the channels for data collection include vehicle speed, motor speed, and motor torque.

[0017] Preferably, the data collection lasts for 30 to 45 days to obtain 100 pure electric vehicle user data families C1, C2, ……, C 100 .

[0018] Preferably, the collection frequencies of the vehicle speed, motor speed, and motor torque collection channels are all 100 Hz.

[0019] Preferably, the calculation of the user load distribution includes the following steps:

[0020] (1) Calculation of the user mileage: Integrate the vehicle speed V(t) collected from the user's vehicle to obtain the mileage of each user.

[0021]

[0022] Among them, t is the cumulative recording time, and V(t) represents the time-domain signal of the vehicle speed collection channel.

[0023] (2) Torque grading: Determine the torque range according to the rated torque and usage characteristics of the motor output. It is divided into P levels from the minimum torque Tmin to the maximum torque Tmax, and the torque difference between each level is:

[0024]

[0025] (3) Speed grading: Determine the speed range according to the rated speed and usage characteristics of the motor output. It is divided into Q levels from the minimum speed Nmin to the maximum speed Nmax, and the speed difference between each level is:

[0026]

[0027] (4) Joint distribution of torque, rotational speed, and number of rotation cycles: The time-domain signal T(t) of the motor torque and the time-domain signal N(t) of the motor rotational speed are segmented starting from time 0 to t according to the range of ΔT. The number of rotation cycles R is calculated from the torque T(t) data at each level of torque and rotational speed, obtaining the joint distribution of torque and number of rotation cycles for each user.

[0028] Preferably, the positive and negative torque damage calculation includes the following steps:

[0029] (1) Torque division: The torque T of the motor is divided into positive torque Tp and negative torque Tn, representing the accelerating torque and the torque during braking and coasting respectively during vehicle driving:

[0030] T = Tp (T ≥ 0),

[0031] T = Tn (T < 0);

[0032] (2) Torque equivalence: The equivalent torque at each level is calculated as damage and represented by the equivalent number of rotation cycles. The positive torque is equivalent to Tph, and the negative torque is equivalent to Tnh. The equivalent formula is as follows:

[0033] Rp = (Tp / Tph) b ·R,

[0034] Rn = (Tn / Tnh) b ·R,

[0035] where Tph = 300 N·m, Tnh = -300 N·m, b = 8;

[0036] (3) Damage quantification in terms of number of rotation cycles: The sum of the equivalent number of rotation cycles of the positive torque gives the damage of the positive torque, quantitatively represented by the number of rotation cycles Rp. The damage number of rotation cycles of the positive torque of user C1 is represented as C 1Rp ; The sum of the equivalent number of rotation cycles of the negative torque gives the damage of the negative torque, quantitatively represented by the number of rotation cycles Rn. The damage number of rotation cycles of the negative torque of user C1 is represented as C 1Rn ;

[0037] Rp = Σ(Tpij),

[0038] Rn = Σ(Tnij),

[0039] Obtaining 100 sample data of the damage number of rotation cycles of positive and negative torques C 1Rp 、C 2Rp 、……C 100Rp and C 1Rn 、C 2Rn 、……C 100Rn ;

[0040] (4) Mileage extrapolation: Determine the user's durability target mileage G, and obtain the positive and negative torque damages of 100 users after extrapolating the sample mileage:

[0041] Dpi = G·C iRp / L i ,

[0042] Dni = G·C iRn / L i 。

[0043] Preferably, the specific operation of step 3 is as follows: Calculate the Weibull distribution for each sample of negative torque damage and positive torque damage respectively, obtain the target damage value used by 95% of users, and obtain the positive and negative torque damage targets of users.

[0044] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0045] 1. Based on the actual use of pure electric vehicles, the present invention conducts user vehicle data collection, determines the user load distribution, formulates the durability target of the user's driveline, extracts the typical working conditions of users, and equivalent them to the working conditions of the test field, so as to formulate the acceleration durability test method for pure electric vehicles. The present invention starts from users and then goes back to users, taking data as the only criterion, having both accuracy and the characteristic of improving test acceleration.

[0046] 2. Through the designed user data collection scheme, the present invention can obtain the load conditions of the user's driveline with the fewest channels; adopt the torque equivalent method to compare and quantify the target values of the driveline load; adopt the separation of positive and negative torques, and the relative damage of torque, speed and rotation times to quantify the driveline load, which can fully reflect the damage characteristics of the acceleration, braking and coasting of electric vehicles, and can conduct load quantification comparison of different vehicle models; for the user working conditions, adopt the three-dimensional joint distribution representation method of speed, torque and rotation times, which can not only truly reflect the actual use of users, but also clearly determine the corresponding working conditions of the test field;

[0047] 3. The present invention is a driveline durability test method at the whole vehicle level of pure electric vehicles, which changes the subjective speculation test equivalent based on traditional vehicles in the past and has positive significance in aspects such as the lightweight, endurance and durability of electric vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a schematic flow chart for establishing the acceleration durability test method described in the present invention;

[0049] Figure 2 is a schematic diagram of the overall working conditions of the user described in Embodiment 1;

[0050] Figure 3 is a schematic diagram of the process of calculating the rotation times for each stage of torque and speed in Embodiment 6;

[0051] Figure 4The Weibull distribution diagram of negative torque described in Embodiment 8;

[0052] Figure 5 The Weibull distribution diagram of positive torque described in Embodiment 8. Detailed implementation manners

[0053] To make the technical solutions of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the specification of the present invention. It should be noted that the following embodiments are only used to better understand the technical solutions of the present invention and should not be construed as a limitation to the present invention.

[0054] Embodiment 1.

[0055] This embodiment provides a method for constructing an acceleration durability test specification for a pure electric vehicle powertrain. The schematic flow diagram of the method is shown in Figure 1 , and includes the following steps:

[0056] Step 1, user data collection: Install a data collector on the vehicle to be tested, connect the vehicle OBD to obtain power and CAN information, and then return it to the user. After the vehicle ignition switch is turned on, the data collector automatically starts collecting data according to the user's normal driving habits and usage characteristics, and automatically stops after the user turns off the ignition switch. The data is collected and stored in the collector card as it is collected;

[0057] Step 2, data processing: including user load distribution calculation and positive and negative torque damage calculation;

[0058] Step 3, determine user goals;

[0059] Step 4, user working condition extraction: Put the load distributions of all users together to form an overall working condition diagram of the users. Draw 4 points for positive and negative torques on the diagram. The information of each point is torque and speed, which is the working condition of the users; it not only better covers the user's usage range but also plays the role of an acceleration test, such as Figure 2 shown as Ap1 to Ap4, An1 to An4. Figure 2 It is a schematic diagram of the overall working condition of the user. In the figure, the X-axis is torque, divided into P levels from Tmin to Tmax, the Y-axis is speed, divided into Q levels from Nmin to Nmax, and the Z-axis is the number of turns, identified by different color blocks, increasing in turn from blue to red. The color of the outer circle gradually transitions from blue to common color inward. Figure 2 The test working conditions are determined by the point selection method, adopting the method of 4 points for positive and negative torques respectively. When selecting points, based on the outer envelope points of the user's torque and speed, combined with the T-N load characteristics of the drive motor, the torques and speeds of A p1 , A p2 , A p3 , A p4 for positive torque and A for negative torque are determined in turn, and...n1 、A n2 、A n3 、A n4 The torque and rotational speed of A. On this basis, through the acceleration operation of the whole vehicle and in coordination with the accelerator pedal, four test conditions with positive torque can be determined and combined. Through coasting and braking, in coordination with the braking deceleration, four test conditions with negative torque can be determined and combined. These conditions are the basic conditions of the test standard. By calculating the equivalent number of turns, it can be equivalent to the test standard;

[0060] Step 5: Determination of the test field conditions: Determine the starting rotational speed, ending rotational speed, and the starting and ending ranges of the torque for 8 conditions according to the characteristics of the points in the user condition diagram. The range of the torque is reflected by the opening degree of the accelerator pedal during driving;

[0061] Step 6: Equivalence between the user and the test field: After collecting the motor rotational speed and torque under the conditions of the test field, by optimizing the number of cycles of the matching conditions, the damage number of turns of the positive and negative torques is made consistent with the user's target;

[0062] Step 7: Divide the conditions and the number of cycles of the test field into multiples of 10 and perform small cycle operations in sequence to form an acceleration test method.

[0063] Example 2.

[0064] This example is a further illustration of Example 1. The distribution principle of the vehicles to be tested is as follows: Shanghai and Shenzhen in first-tier cities, Nanjing, Chongqing, Hangzhou, Wuhan, Kunming, and Changchun in second-tier cities, and Sanya and Xiamen in third-tier cities. 10 users are determined in each city, including 6 operating vehicles and 4 private cars.

[0065] Example 3.

[0066] This example is a further illustration of Example 1. The data acquisition channels include vehicle speed, motor rotational speed, and motor torque.

[0067] Example 4.

[0068] This example is a further illustration of Example 2. The data acquisition lasts for 30 to 45 days to obtain 100 pure electric vehicle user data sets C1, C2, ……, C 100 .

[0069] Example 5.

[0070] This example is a further illustration of Example 4. The acquisition frequencies of the vehicle speed, motor rotational speed, and motor torque acquisition channels are all 100 Hz.

[0071] As shown in the following table,

[0072]

[0073] In the user data acquisition solution designed in this embodiment, the regionality, sample number, acquisition frequency, acquisition time, etc. of the vehicle fully consider the coverage of the data, avoiding the deviation caused by random sampling of the data.

[0074] Embodiment 6.

[0075] This embodiment is a further illustrative example of Embodiment 5. The calculation of the user load distribution includes the following steps:

[0076] (1) The user mileage calculation: Integrate the vehicle speed V(t) collected from the user's vehicle to obtain the mileage of each user;

[0077]

[0078] where t is the cumulative recording time, and V(t) represents the time-domain signal of the vehicle speed acquisition channel;

[0079] (2) The torque grading: Determine the torque range according to the rated torque and usage characteristics of the motor output. Divide it into P levels from the minimum torque Tmin to the maximum torque Tmax, and the torque difference between each level is:

[0080]

[0081] (3) The speed grading: Determine the speed range according to the rated speed and usage characteristics of the motor output. Divide it into Q levels from the minimum speed Nmin to the maximum speed Nmax, and the speed difference between each level is:

[0082]

[0083] (4) The combined distribution of torque and rotational speed revolution number: For the time-domain signal T(t) of the motor torque and the time-domain signal N(t) of the motor speed, starting from time 0 to t, segment according to the range of ΔT. Calculate the number of revolutions R of the data of the torque T(t) at each level of torque and speed, and obtain the combined distribution of torque and revolution number for each user.

[0084] The schematic diagram of the process of calculating the number of revolutions for each level of torque and speed in the segmentation is as Figure 3, according to the torque grading, when the time-domain data of the torque MCU_ActTMTorque is within a level, such as Ti, as shown by the red curve in the figure, there will be several data segments at this level of torque, corresponding to time lengths of Δt1, Δt2, Δt3,.... Taking time as the reference, there will also be corresponding rotational speed signal segments in the corresponding time periods. These segments are segmented and extracted according to the rotational speed grading range, and the number of rotation cycles at each rotational speed level is calculated. Cumulatively in this way, the number of cycles at the same torque level and the same rotational speed level is obtained, which is the cycle number distribution under torque and rotational speed.

[0085] The calculation results are shown in the following table.

[0086]

[0087]

[0088] Example 7.

[0089] This example is a further illustration of Example 5. The positive and negative torque damage calculation includes the following steps:

[0090] (1) Torque division: The torque T of the motor is divided into positive torque Tp and negative torque Tn, which respectively represent the acceleration torque and the torque during braking and coasting in the vehicle driving process:

[0091] T = Tp (T ≥ 0),

[0092] T = Tn (T < 0);

[0093] (2) Torque equivalence: The equivalent amount of torque at each level is calculated into damage, represented by the equivalent number of cycles. The positive torque is equivalent to Tph, and the negative torque is equivalent to Tnh. The equivalent formula is as follows:

[0094] Rp = (Tp / Tph) b ·R,

[0095] Rn = (Tn / Tnh) b ·R,

[0096] where Tph = 300 N·m, Tnh = -300 N·m, b = 8;

[0097] (3) Damage cycle quantification: The sum of the cycles after positive torque equivalence is the damage of the positive torque, quantitatively represented by the number of cycles Rp. The damage cycle number of the positive torque of user C1 is represented as C 1Rp ; The sum of the cycles after negative torque equivalence is the damage of the negative torque, quantitatively represented by the number of cycles Rn. The damage cycle number of the negative torque of user C1 is represented as C 1Rn ;

[0098] Rp = Σ(Tpij),

[0099] Rn = Σ(Tnij),

[0100] Obtain 100 sample data C for the number of cycles of positive and negative torque damage each 1Rp 、C 2Rp 、……C 100Rp and C 1Rn 、C 2Rn 、……C 100Rn ;

[0101] (4) Mileage extrapolation: Determine the target mileage G of user durability. After extrapolating the sample mileage, obtain the positive and negative torque damage of 100 users:

[0102] Dpi = G · C iRp / L i ,

[0103] Dni = G · C iRn / L i .

[0104] Example 8.

[0105] This example is a further illustration of Example 1. The specific step 3 is as follows: Calculate the Weibull distribution for each sample of negative torque damage and positive torque damage respectively to obtain the target damage value for 95% of users, and obtain the positive and negative torque damage targets of users. The Weibull distribution diagram of negative torque is shown in Figure 4 , and each point shown in the figure is Dni. Calculate the equivalent damage of the negative torque of each obtained user. According to experience, the life data conforms to the Weibull distribution, and the graph is as shown. Each point in the figure is a user, and the value is the probability distribution from 0 to 100%. The negative torque damage distribution of electric vehicles generally takes a value not lower than 90% probability.

[0106] The Weibull distribution diagram of positive torque is shown in Figure 5 , calculate the equivalent damage of the positive torque of each obtained user. According to experience, the life data conforms to the Weibull distribution, and the graph is as shown. Each point in the figure is a user, and the value is the probability distribution from 0 to 100%. The positive torque damage distribution of electric vehicles generally takes a value not lower than 95% probability.

Claims

1. A construction method for the acceleration durability test specification of a pure electric vehicle powertrain, characterized in that It includes the following steps: Step 1, User data collection: Install a data collector on the vehicle to be tested, connect it to the vehicle OBD to obtain power and CAN information, and then return it to the user. After the vehicle ignition switch is turned on, the data collector automatically starts collecting data according to the user's normal driving habits and usage characteristics, and automatically stops when the user turns off the ignition switch. The data is collected and stored in the collector card as it is collected; Step 2, Data processing: It includes user load distribution calculation and positive and negative torque damage calculation; Step 3, Determine the user target; Step 4, User working condition extraction: Put all the load distributions of users together to form an overall working condition graph of users. Draw 4 points for positive and negative torques on the graph, and the information of each point is torque and speed, which is the working condition of the user; Step 5, Determination of the test field working condition: Determine the starting speed, ending speed, and starting and ending ranges of torque for 8 working conditions according to the characteristics of the points in the user working condition graph. The range of the torque is reflected by the opening of the accelerator pedal during driving; Step 6, Equivalence between the user and the test field: After collecting the motor speed and torque through the working conditions of the test field, by optimizing the number of cycles of the matching working conditions, the number of damage cycles of positive and negative torques is made consistent with the user's target; Step 7, Divide the working conditions and the number of cycles of the test field into multiples of 10, and perform small cycle operations in sequence to form an acceleration test method.

2. The construction method of the acceleration durability test specification for the powertrain of a pure electric vehicle according to claim 1, wherein, The distribution principle of the vehicle to be tested is as follows: Shanghai and Shenzhen in first-tier cities, Nanjing, Chongqing, Hangzhou, Wuhan, Kunming, Changchun in second-tier cities, Sanya and Xiamen in third-tier cities. 10 users are determined in each city, including 6 operating vehicles and 4 private cars.

3. The construction method of the acceleration durability test specification for the powertrain of a pure electric vehicle according to claim 1, wherein, The channels for data collection include vehicle speed, motor speed, and motor torque.

4. The construction method of the acceleration durability test specification for the powertrain of a pure electric vehicle according to claim 2, wherein, The data collection lasts for 30 to 45 days, obtaining 100 pure electric vehicle user data families C1, C2, ……, C 100 .

5. The method for constructing the acceleration durability test specification of the powertrain of a pure electric vehicle according to claim 3, wherein, The collection frequency of the vehicle speed, motor speed, and motor torque collection channels is all 100Hz.

6. The construction method of the acceleration durability test specification for the powertrain of a pure electric vehicle according to claim 5, wherein The user load distribution calculation includes the following steps: (1) User mileage calculation: Integrate the vehicle speed V(t) collected from the user's vehicle to obtain the mileage of each user; ， where t is the cumulative recording time, and V(t) represents the time-domain signal of the vehicle speed collection channel; (2) Torque grading: Determine the torque range according to the rated torque output of the motor and its usage characteristics. Divide it into P levels from the minimum torque Tmin to the maximum torque Tmax, and the torque difference between each level is: ； (3) Speed grading: Determine the speed range according to the rated speed output of the motor and its usage characteristics. Divide it into Q levels from the minimum speed Nmin to the maximum speed Nmax, and the speed difference between each level is: ； (4)Combined distribution of torque, rotational speed, and number of rotations: Starting from time 0 to t, segment the time-domain signal T(t) of the motor torque and the time-domain signal N(t) of the motor rotational speed according to the range of Calculate the number of rotations R for the torque T(t) at each level of torque and rotational speed, and obtain the combined distribution of torque and number of rotations for each user.

7. The method for constructing an acceleration durability test specification for a pure electric vehicle powertrain according to claim 5, wherein The positive and negative torque damage calculation includes the following steps: (1) Torque division: The torque T of the motor is divided into positive torque Tp and negative torque Tn, which represent the accelerating torque and the torque of braking and coasting during vehicle driving respectively: T = Tp (T≥0), T = Tn (T<0); (2) Torque equivalence: Calculate the equivalent of the torque at each level into damage, expressed by the equivalent number of cycles. The positive torque is equivalent to Tph, and the negative torque is equivalent to Tnh. The equivalent formula is as follows: Rp = (Tp / Tph) b ·R, Rn = (Tn / Tnh) b ·R, where Tph = 300N.m, Tnh = -300 N.m, b = 8; (3) Damage quantification in terms of number of turns: The sum of the number of turns after positive torque equivalence gives the damage of the positive torque, which is quantified in terms of the number of turns as Rp. The damage number of turns of the positive torque of user C1 is represented as C 1Rp ; The sum of the number of turns after negative torque equivalence gives the damage of the negative torque, which is quantified in terms of the number of turns as Rn. The damage number of turns of the negative torque of user C1 is represented as C 1Rn ; Rp = Σ(Tpij), Rn = Σ(Tnij), Get 100 sample data of positive and negative torque damage circles C 1Rp 、C 2Rp ,……C 100Rp and C 1Rn 、C 2Rn ,……C 100Rn ; (4)Mileage extrapolation: Determine the target mileage G of user durability. After extrapolating the sample mileage, obtain the positive and negative torque damages of 100 users: Dpi = G·C iRp / L i , Dni = G·C iRn / L i 。 8. The construction method of the acceleration durability test specification for the powertrain of a pure electric vehicle according to claim 1, wherein Specifically, step 3 is as follows: Calculate the Weibull distribution for each sample of negative torque damage and positive torque damage respectively to obtain the target damage value for 95% of users, and obtain the positive and negative torque damage targets of users.

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