A method for evaluating reliability and durability of a pure electric bus under a cycle working condition

Abstract

The application discloses a kind of reliable and durability evaluation methods of pure electric bus under cycle working condition, belong to pure electric bus reliability verification technical field.The application is by correlating theory and practice to carry out reliable and durability evaluation of pure electric bus, using the integrated method of CAE analysis+parts test+body-in-white plus chassis bench test+vehicle road test verification, comprehensively improves the one-time pass rate of subsequent physical test, reaches the test method of quickly verifying body, chassis and electrical appliances, reduces development cost and risk, improves pure electric bus product quality.The problem of "completing vehicle reliability verification in one way, problem verification is insufficient and not thorough" in the prior art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of reliability verification of pure electric buses, in particular to a reliability and durability evaluation method of pure electric buses under cyclic working conditions. BACKGROUND

[0002] The statements in this section merely provide background information related to the present application and do not necessarily constitute the prior art.

[0003] The reliability of a bus product is an important indicator for measuring the safety quality and fatigue life of the product, and the reliability of the product is closely related to personal safety and economic benefits. A pure electric bus is composed of many batteries, motors and electronic control systems. If a small part of one of them is damaged or fails, it may cause a safety accident of the bus and cause serious consequences. At the same time, with the rapid development of pure electric vehicles, the competition in the bus industry is becoming more and more fierce, and competitors are competing in quality, price, and speed of updating. Therefore, the requirements for product quality, reliability, development cost, and operating cost during the life cycle of the bus are becoming higher and higher. Therefore, the reliability test verification of the bus product is particularly important.

[0004] At present, the traditional bus reliability test technology mainly includes CAE simulation analysis, bench simulation test and test field road test. Most of the main machine factories complete the vehicle reliability verification by one of the above methods, and few use two or three methods in association. Generally, the bench and the road test are not associated and do not form a complement. At present, CAE is simulated according to standard working condition boundary conditions, and less analysis is carried out under real load conditions; the bench test also does not verify the structure combined with CAE analysis; the comprehensive verification degree of the test field road test is relatively high, but most enterprises do not design test schemes according to the specific vehicle state, resulting in insufficient and incomplete problem verification and other problems. SUMMARY

[0005] The verification method combining CAE analysis, bench simulation and test field road test can quickly verify, shorten the test cycle, comprehensively and efficiently verify the three-electric system of the pure electric bus, improve the test verification effect and has high repeatability, can make up for the product market problems caused by insufficient verification, and is the main research direction for improving the product reliability of the pure electric bus.

[0006] In order to solve the problems of the prior art, the present application provides a reliability and durability evaluation method of pure electric buses under cyclic working conditions, which can efficiently verify the reliability before the batch production of pure electric buses, not only discovers and solves problems in advance, but also solves the problems of many sample vehicle development quantities and high costs, and effectively creates good benefits for enterprises.

[0007] The application provides a pure electric bus reliability and durability evaluation method under a cycle working condition;

[0008] A pure electric bus reliability and durability evaluation method under a cycle working condition, comprising the following steps:

[0009] S1, according to the pure electric bus design data, the pure electric bus is simulated and analyzed to determine whether there is a potential failure risk; if not, step S2 is performed;

[0010] S2, after the engineering design of the pure electric bus is completed, the durability test of the components and the whole vehicle system of the pure electric bus is performed to determine whether the state before the components are installed meets the design requirements; if yes, step S3 is performed;

[0011] S3, after the vehicle base is installed, the road load spectrum of the reinforced road is collected in the "white body + chassis" state, and the four-post vibration test is performed on the four-post vibration test bench;

[0012] S4, after the physical sample vehicle is manufactured, the vehicle road load spectrum is collected, and the user correlation test is carried out in combination with the road conditions and the failure;

[0013] S5, the road load spectrum of the pure electric bus in the use process is obtained through the user correlation test, and the whole vehicle test field test is carried out.

[0014] Further, after step S3 and before step S4, the following steps are further included:

[0015] Strain gauges and sensors are installed at the weak points of the simulation analysis.

[0016] Further, according to the pure electric bus design data, the pure electric bus is subjected to CAE simulation analysis.

[0017] Further, according to the pure electric bus design data, the pure electric bus is subjected to simulation analysis to determine whether there is a potential failure risk, and the specific steps include:

[0018] The design data of the body, suspension, steering, tire and bushing are obtained and decomposed, and an ADAMS dynamics model is established;

[0019] According to the ADAMS dynamics model and the decomposed design data, a whole vehicle multi-rigid-body dynamics simulation model is established and driven to obtain the load spectrum on each connection point of the white body, and a finite element stress field analysis of the white body is performed;

[0020] The strength and fatigue of the components are calculated in combination with the boundary load conditions to predict whether the components have a potential failure risk.

[0021] Further, the specific steps of the durability test of the components and the whole vehicle system of the pure electric bus are:

[0022] Under real boundary conditions, the component and the whole vehicle system of the pure electric bus are tested for durability damage under simulated vehicle running state by using the MAST six-degree-of-freedom vibration table excitation source.

[0023] The durability damage test result is compared with the simulation analysis result.

[0024] Further, under the state of "body-in-white + chassis", the reinforced road load spectrum is collected, and the specific steps of the four-column vibration test on the four-column vibration test bench are

[0025] The reinforced road load spectrum is collected, and the four-column vibration table is iterated to simulate the load excitation test of the vehicle in the state of "body-in-white + chassis" on the road.

[0026] Further, the specific steps of the user correlation test combined with the road load spectrum, road conditions and faults are

[0027] The road load spectrum of the vehicle is obtained through the six-component test technology, and the load input data in the user use process are counted;

[0028] The road load spectrum, load input data and road conditions and faults in the use process of the vehicle are combined to carry out the test field test of the pure electric bus.

[0029] Further, the specific steps of the vehicle test field test carried out by the user correlation test to obtain the road load spectrum in the use process of the pure electric bus are:

[0030] The road load spectrum in the use process of the pure electric bus is obtained through the user correlation test, the equivalent test field road conditions are iterated, the vehicle reliability road test scheme is designed, and the test road conditions are combined according to a certain proportion to carry out the vehicle test field test.

[0031] Further, after the simulation analysis is completed, if there is no potential failure risk, the engineering design of the pure electric bus is started;

[0032] After the durability test is completed, if the state of the component before being mounted on the vehicle meets the design requirements, the vehicle base is mounted;

[0033] After the four-column vibration test is passed, the physical sample vehicle is manufactured;

[0034] After the user correlation test and the vehicle test field test are passed, the batch production of the vehicle is started.

[0035] Further, if a step is qualified, the next step is carried out.

[0036] Compared with the prior art, the beneficial effects of the present application are:

[0037] 1、The technical scheme provided by the application correlates theoretical analysis with practice, adopts an integrated verification method of CAE simulation analysis, part + whole vehicle bench test and whole vehicle road test, can quickly and comprehensively verify, effectively shortens the test cycle, has good repeatability, and completely solves the technical bottleneck problems of insufficient traditional test verification, high cost and long test cycle;

[0038] 2、The technical scheme provided by the application can decompose the verification in advance to the CAE theoretical stage, ensure that the theoretical design is correct before carrying out engineering design, fully identify the failure risk problem, identify the risk in advance, and improve the one-time pass rate of subsequent physical test;

[0039] 3、The technical scheme provided by the application solves the problems of few sample vehicles in the development stage, long verification period and low precision, reduces the product development cost and risk, and improves the product quality. Combined with the whole vehicle reliability growth system, the digital transformation of product reliability and durability test is realized, and good benefits are created for enterprises. BRIEF DESCRIPTION OF DRAWINGS

[0040] The drawings accompanying the specification of this application form a part of this application and serve to further illustrate the illustrative embodiments of the application and to explain the principles of the application, but are not intended to limit the application.

[0041] Figure 1 The flowchart provided for the embodiments of the application. DETAILED DESCRIPTION

[0042] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the application. Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the application pertains.

[0043] It should be noted that the terms used herein are only for the purpose of describing the specific embodiments, and are not intended to limit the exemplary embodiments according to the application. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form, and in addition, it should be understood that the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0044] The embodiments in the application and the features in the embodiments can be combined with each other without conflict.

[0045] Term explanation:

[0046] Cycle condition: refers to combining vehicle operation, sorting and combining different test pavements in a certain proportion to form a specific condition, and verifying the reliability of the vehicle under the condition.

[0047] White body + chassis state: the state of the pure electric bus framework, skin and chassis.

[0048] Example one

[0049] The existing bus reliability verification does not associate the bench and road test to form a complement, and does not conduct targeted verification, resulting in insufficient and incomplete problem verification; therefore, the present application provides a kind of.

[0050] Next, combined with Figure 1 A kind of pure electric bus reliability and durability evaluation method under the cycle condition disclosed in the embodiment is described in detail. The pure electric bus reliability and durability evaluation method under the cycle condition includes the following steps:

[0051] S1, according to the design data of pure electric bus, the simulation analysis of pure electric bus is carried out, and whether there is potential failure risk is judged;The specific steps include:

[0052] S101, obtain the design data of body, suspension, steering, tire and bushing and decompose, and establish ADAMS dynamics model;Specifically, the design data of body, suspension, steering, tire and bushing is input into ADAMS mechanical system dynamics simulation analysis software, in ADAMS mechanical system dynamics simulation analysis software, ADAMS mechanical system dynamics simulation analysis software decomposes the design data of each component according to the need, establishes ADAMS dynamics model, and ADAMS dynamics model includes suspension system model, steering system model, powertrain model and white body model. The suspension system model, steering system model, powertrain model and white body model are three-dimensional simulation models corresponding to the parts.

[0053] S102, according to ADAMS dynamics model and decomposed design data, establish whole vehicle multi-rigid body dynamics simulation model and drive, obtain load spectrum on each connection point of white body, and carry out finite element stress field analysis on white body at the same time;

[0054] Specifically, the suspension system model, steering system model, powertrain model, and body-in-white model are integrated using CAE simulation analysis software to establish a multi-rigid-body dynamics simulation model of the whole vehicle. The six-component load is used as the iterative target signal to iterate on a virtual test bench to obtain the displacement of the virtual test bench actuator in the test bench and extract the load spectrum of the connection points on the body-in-white. The load spectrum is then input into the CAE simulation analysis software to perform finite element stress field analysis on the body-in-white.

[0055] S103. Combine boundary conditions to perform component strength and fatigue calculations and predict whether there are potential failure risks in the component; specifically, in CAE simulation analysis software, perform simulation analysis on the component by applying force, displacement and acceleration, and calculate the maximum stress it will bear when it fails.

[0056] If it does not exist, proceed to step S2;

[0057] S2. Conduct engineering design for the pure electric bus. After the engineering design of the pure electric bus is completed, perform durability tests on the components and the entire vehicle system to determine whether the condition of the components before installation meets the design requirements; if so, proceed to step S3; the specific steps include:

[0058] S201. Using real boundary conditions, namely the loads and constraints of the physical prototype of the pure electric bus, and utilizing the MAST six-degree-of-freedom vibration table excitation source, durability damage tests are conducted on the components and the entire vehicle system of the pure electric bus under simulated vehicle operating conditions. Specifically, the load spectrum is input into the MAST six-degree-of-freedom vibration table, and the MAST six-degree-of-freedom vibration table vibrates to verify the reliability and durability of the components.

[0059] S202. Compare the durability damage test results with the simulation analysis results to verify and confirm the accuracy of the simulation, thereby saving the test verification cost of vehicles on the same platform.

[0060] S3. Perform vehicle basic assembly. After the vehicle basic assembly is completed, collect the road load spectrum of the reinforced road surface and iterate to the four-column vibration table. For the vehicle in the "body-in-white + chassis" state, simulate the load excitation test of the vehicle on the road surface.

[0061] Among them, through test driving at the test track, an acceleration sensor was installed on the vehicle to obtain the road load spectrum of the reinforced road surface at the test track. After the load spectrum was collected, it was processed. Combining the requirements of the four-column test bench and the reinforcement test effect, the load spectrum was compressed and superimposed.

[0062] S4. After the physical prototype is built, road load spectra are collected for the vehicle, and user-related tests are conducted in conjunction with road conditions and faults; specific steps include:

[0063] S401, obtain the road load spectrum of the vehicle through the six-component force test technology, and count the load input data in the use process of the user; specifically, the road load spectrum of the user in the running of the vehicle is obtained by installing a six-component force meter on the tire.

[0064] S402, combine the road load spectrum, the load input data, and the road conditions and faults faced in the use process of the vehicle, and perform a test field test of the pure electric bus.

[0065] S5, obtain the road load spectrum in the use process of the pure electric bus through the user correlation test, iterate the equivalent test field road conditions, design a whole vehicle reliability road test scheme, combine the test road conditions according to a certain proportion to perform a whole vehicle test field test. After the whole vehicle test field test, the production of the sample vehicle is performed. The road excitation intensity of the user vehicle in the actual running is collected through the six-component force meter, and the intensity of the reliability test road of the test field is combined to design a road test scheme of the vehicle, so as to reduce the test redundancy.

[0066] The road surfaces such as the stone road, the grating road, the long wave road, and the Belgium road are combined according to a certain mileage proportion through the strengthening coefficients of the test field road surfaces.

[0067] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for evaluating the reliability and durability of a pure electric bus under cyclic operating conditions, characterized in that, Includes the following steps: S1. Based on the design data of the pure electric bus, perform simulation analysis on the pure electric bus to determine whether there are any potential failure risks; if not, proceed to step S2. S2. After the engineering design of the pure electric bus is completed, durability tests are conducted on the components and the whole vehicle system of the pure electric bus to determine whether the state of the components before installation meets the design requirements; if so, proceed to step S3. S3. After the vehicle is basically assembled, in the state of "body-in-white + chassis", the road load spectrum of the reinforced road surface is collected, and the four-column vibration test is carried out on the four-column vibration table. The specific steps are: collect the road load spectrum of the reinforced road surface, iterate to the four-column vibration table, and simulate the load excitation test of the vehicle on the road surface for the vehicle in the state of "body-in-white + chassis". S4. After the physical prototype is built, the road load spectrum of the vehicle is collected, and user correlation tests are carried out in combination with road conditions and faults. S5. Obtain the road load spectrum during the use of pure electric buses through user correlation tests and conduct whole vehicle test track tests. The specific steps are as follows: obtain the road load spectrum during the use of pure electric buses through user correlation tests, iterate the equivalent test track road conditions, design a whole vehicle reliability road test scheme, and conduct whole vehicle test track tests on the test road conditions according to a certain proportion combination.

2. The method for evaluating the reliability and durability of pure electric buses under cyclic operating conditions as described in claim 1, characterized in that, The steps following step S3 and before step S4 are as follows: Strain gauges and sensors are installed at the weak points in the simulation analysis.

3. The method for evaluating the reliability and durability of pure electric buses under cyclic operating conditions as described in claim 1, characterized in that, Based on the design data of the pure electric bus, CAE simulation analysis was performed on the pure electric bus.

4. The method for evaluating the reliability and durability of pure electric buses under cyclic operating conditions as described in claim 1, characterized in that, Based on the design data of the pure electric bus, the specific steps for conducting simulation analysis on the pure electric bus to determine whether there are potential failure risks include: Acquire and decompose the design data of the body, suspension, steering, tires and bushings, and establish an ADAMS dynamic model; Based on the ADAMS dynamic model and the decomposed design data, a multi-rigid-body dynamic simulation model of the whole vehicle is established and driven to obtain the load spectrum at each connection point of the body-in-white, and at the same time, finite element stress field analysis is performed on the body-in-white. By combining boundary load conditions, the strength and fatigue of components are calculated to predict whether there are potential failure risks in the components.

5. The method for evaluating the reliability and durability of pure electric buses under cyclic operating conditions as described in claim 1, characterized in that, The specific steps for conducting durability tests on components and the entire vehicle system of a pure electric bus are as follows: Using real boundary conditions and the MAST six-degree-of-freedom vibration table excitation source, durability damage tests were conducted on the components and the whole vehicle system of a pure electric bus under simulated vehicle operating conditions. The results of durability damage tests were compared with the results of simulation analysis.

6. The method for evaluating the reliability and durability of a pure electric bus under cyclic operating conditions as described in claim 1, characterized in that, The specific steps for collecting vehicle road load spectra, combining road conditions and faults, and conducting user correlation tests are as follows: By using the six-component force testing technology, the road load spectrum of the vehicle is obtained, and the load input data during user use is statistically analyzed. By combining road load spectrum, load input data, and road conditions and faults encountered during vehicle use, pure electric bus test track tests are conducted.

7. The method for evaluating the reliability and durability of pure electric buses under cyclic operating conditions as described in claim 1, characterized in that, If no potential failure risk is found after the simulation analysis is completed, the engineering design of the pure electric bus will begin. After the durability test is completed, if the condition of the component before installation meets the design requirements, the vehicle basic assembly will proceed. After the four-column vibration test is passed, a physical prototype is manufactured. After passing user-related tests and vehicle proving ground tests, mass production of the vehicles will begin.

8. The method for evaluating the reliability and durability of a pure electric bus under cyclic operating conditions as described in claim 1, characterized in that, Only if a step passes the evaluation can the next step be carried out.

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