A qualified car, before leaving the factory, whether the body or parts, should be subject to strict testing before it can be put into the market.But the automobile spare parts test this matter, must tell from the main engine factory and the spare parts supplier two aspects.This problem is too big, first from the process to introduce.How to do the parts test, from the main engine plant and parts suppliers will be two aspects.
For the main engine plant, more concerned about the parts installed in the car full of performance requirements, full of reliability requirements, quality stability is not stable.Therefore, at the early stage of product design, design requirements will be put forward for each part. These requirements may come from regulations or enterprise standards, such as seat pulling strength.It may be from the actual use of customers, such as the surface stiffness of the dashboard;It may be decomposed from the performance requirements of the vehicle, such as the sound loss curve of the front acoustic envelope;It may be proposed from the requirements of the quality assurance of the vehicle fatigue endurance life requirements, such as the chassis durability life;Consistency requirements may arise from quality requirements, such as part size reports;It may also come from previous project experiences or from DFMEA/DFSS.All in all, these requirements together form a subsystem technical specification or a part technical specification. This document is the technical requirements for parts/subsystems and the guiding document for parts development.
After determining the technical specifications of the parts, the certification department of the main engine factory will make advplan according to these specifications, and specify the tests that all parts and subsystems need to carry out in each stage of development.The product engineer will write these requirements into SOR. During the procurement process, the technical approval will be given to the supplier's test capability.At the time of each loading and sample delivery, the product engineer and certification engineer shall check whether each part has completed all the tests specified and sign on each test report.I have been responsible for a small white body assembly, is simple, but pay sample each type of material are required to have a warranty, in fact, the material test report, each solder joint to do more than three times the chisel test to confirm process robustness, have piece and the size of the assembly report at all levels, all qualified YangZhuang car is allowed.If there is a rush to load the car is not qualified, it is necessary to have a layer upon layer of approval of the rectification plan and assessment of risk under the premise of receiving loading.Therefore, it is one of the core capabilities of the whole vehicle factory to make clear the requirements of parts, form standards and establish a standardized process system to verify and approve parts.Through long-term product development, the international large factory has accumulated rich experience and has a large database to support these work. Engineers only need to select the right template from the database when they do the development.Now the domestic main engine manufacturers are also catching up, and because it is from the beginning, and sometimes understand these technical requirements more deeply.
For suppliers, they are more concerned about how to design parts that meet the requirements of the main engine factory. Some suppliers with strong technical strength have their own enterprise standards. When designing parts, they can meet their own enterprise standards and meet the requirements of most main engine factories.In any case, the APQP plan and the corresponding budget need to be developed at the early stage of the project development, and then submitted to the main engine plant for approval. After the confirmation, the specified test needs to be completed before each key node.Generally divided from the type of test, can be divided into performance test, development test, reliability test and quality consistency test, sometimes, will do the performance of the standard parts feel the bottom test.According to the development stage, it can be divided into DV test and PV test.With the continuous development of CAE technology, some tests can be replaced by virtual simulation, and some main machine manufacturers also recognize that suppliers can replace physical tests by virtual simulation to reduce development costs.
Severe external environment and climate impact, resulting in function decay and failure, affect the service life of the car.The quality of car parts directly determines the quality of the whole car, so in the new product development stage or in the car production process, if the data and process changes will be carried out component quality experiments, to ensure product quality.The reliability test of the whole car can also check the quality of parts, but the check of most parts is not sufficient, and the cost is large, the cycle is long, so some parts must be done alone bench test.It is an important basic work that the environmental experiment of car parts starts from the development stage of car and continues to the product finalization, production and quality improvement after mass production.
I. introduction to environmental experiments of car parts
The environmental test of car parts is mainly to evaluate the environmental adaptability of the selected data, assembly and parts of the product. It requires that the car parts are not damaged or can work normally under certain environmental factors and strengths, and the functional parameters meet the requirements of the plan.The requirement of laboratory component test is to correctly determine the load according to the experimental conditions, carry out fixture planning, bench installation, experiment and data processing.
1 classification in the formative stage
In the finalization stage, environmental judgment experiments and necessary application of environmental experiments should be carried out to verify whether the environmental adaptability of planned products meets the requirements of regulations, so as to provide decision-making basis for finalization judgment.
2. Classification of production stages
In the production stage, environmental acceptance tests and routine environmental tests should be carried out to verify the stability of the production process and provide decision-making basis for the acceptance of mass production products.
3. Classification of application stages
In the application stage, necessary environmental and natural environmental experiments should be carried out to provide information for evaluating the environmental adaptability of products.
4. Classification of car components
If classified according to the car components, it can be roughly divided into the car electrical parts test, chassis parts test, body and accessories test.
This can be classified into experimental categories
If classified according to experimental types, it can be divided into high and low temperature resistance, humidity test, corrosion test, vibration test and durability test.
Through the experiment, the defects in the car planning can be found in the development stage, and corrective and protective measures can be taken in time, so as to improve the ability of the car to adapt to the environment.
Ii. Influence of climate and environment on product functional quality
1. Environmental classification
1) high temperature environment
High temperature environment will produce thermal effect, make the car parts attack softening, expansion evaporation, gasification, cracking, melting and aging and other phenomena, and the corresponding car will appear mechanical fault, lubrication seal failure, circuit system insulation is poor, mechanical stress increase and strength reduction and other faults.
2) low temperature environment
Low temperature environment will make the car parts attack physical shrinkage, oil solidification, mechanical strength reduction, data embrittlement, loss of elasticity and icing, and other phenomena, and the corresponding car will appear cracks mechanical fault, wear increases, seal failure and poor insulation circuit system and other faults.
3) humid and hot conditions
Environmental humidity will cause the metal surface production data transformation, electrical strength and insulation resistance and electrical function decline.
4) low pressure conditions
The low-pressure effect will reduce the engine and exhaust function, resulting in difficult startup, unstable work, seal failure and electrical function decline.
5) radiation conditions
Solar radiation will produce heating effect and photochemical effect, resulting in aging, embrittlement, expansion, softening viscosity and seal failure.
6) dust environment
Dust environment is easy to cause parts wear and gamble plug, filter failure, electrical sealing function decline.
7) salt fog environment
Chemical reactions may occur in the salt spray environment, resulting in mechanical strength degradation, data corrosion and electrical function changes.
8) rainwater environment
Rain water environment will produce landing infiltration effect, which is easy to make the engine stall, electrical equipment failure, accelerate the corrosion of metal surface.
Iii. Selection of environmental test methods and equipment
With the development of science and technology, experimental equipment has been carried out to the stage of intelligence, virtualization, networking and miniaturization, and has the characteristics of high precision and efficiency, and will continue to carry out along with this trend.According to various environmental conditions, combined with the detection equipment in use, the general environmental test methods of components and the selection of equipment are briefly described.
In the process of vehicle development, the main engine plant carries out a series of tests on components from modules to the vehicle.Performance test includes material test, module test, subsystem test and vehicle test.Take the airbag as an example. As a safety check, there will be many rounds of verification.Airbag involved in, if not fully verified, will cause injury to passengers.The takata airbag incident, which led to the massive recall, is a typical result of inadequate verification.
Module test is divided into DV test and PV test, respectively for design verification and production verification.DV is to verify whether the part design meets the requirements, PV is to verify whether the part supplier's production meets the design requirements, and the stability of the production line quality.DV includes basic performance, high and low temperature conditions, Margen generator airbag deployment time in place.Whether the pressure of the air bag conforms to the goal set by the vehicle safety, and ensure that the damage value of the dummy in the system test is smaller.Generator pressure test, etc.For mature designs, environmental durability can be verified with PV.
PV test adds environmental simulation test on the basis of DV test.The parts used must be molds from the normal production line.Environmental simulation includes dust, temperature shock, temperature and humidity shock, temperature shock, etc.The whole life cycle aging process was realized in the room temperature chamber.After the aging of the parts for basic point explosion, to meet the design requirements.When it comes to environmental durability, it is a long cycle test, which generally takes at least 3 months for a round.The internal testing of sub-parts of the supplier will be more stringent, such as the temperature and humidity test of the generator, and the design redundancy shall be greater than the service life of the whole vehicle.If the verification is not sufficient, such as takata, resulting in the recall of more than 30 million vehicles, which directly led to the bankruptcy of such a supplier of safety system ranked second in the industry and was acquired by zhejiang junsheng electronics.
Material test includes physical properties of all materials, ELV, VOC, four emission, surface coating, etc.General engine factory can have his material storehouse.After strict testing, the new material eye is qualified and then entered into the material warehouse, so as to avoid the time and cost of repeated testing for re-use.
Subsystem test includes performance test and system integration test.Performance test requires the airbag to be loaded together with the environmental parts, static point explosion, and verify the impact on the environmental parts.That includes high and low temperatures, 85, minus 35.If plastic parts are broken, air bags are equivalent, not only can't protect people, but also can cause harm to people.The system integration test was carried out by installing passive safety related parts on Buck body to test the sliding table.Compared with the vehicle crash test can save time and cost.Passive safety parameters can be locked in advance to pave the way for vehicle test.
The vehicle test includes performance test and road test.Performance test verifies the protection effect of dummy in vehicle collision.If the collision score is too low, the strength improvement space of the vehicle is limited at this time. The first simple optimization method is to adjust the air bag parameters.The damage value of dummy can be reduced by adjusting the stiffness of air bag.According to the test results of the whole vehicle, after the air bag parameters are adjusted and locked, DV/PV and subsystem verification shall be carried out again.So you have to do at least two rounds of a set of trials.The more demanding the main engine plant, the longer the vehicle development cycle, the middle needs a lot of verification optimization improvement.The life cycle of a typical vehicle is 5 years. When many high-end main engine manufacturers launch new models, the structure parts of the next generation model have already been fixed.The structure part is the long period, has the underlying influence to the vehicle performance.
Full vehicle road test, MB matching, Crest test, etc. verify appearance, NVH performance, durability, etc.Nowadays, the demand for NVH is more and more high, and NVH is also one of the pain points of most main engine factories.Road test will be carried out in a variety of conditions, in addition to the runway bad road, but also on the plateau, under the basin, winter to heihe, summer to hainan.So the test conditions of the main engine factory must be n times more stringent than the usual conditions for people to use the car.
At present, due to the progress of CAE technology.Simulation analysis on synchronization part test.Such as early strength simulation, mid-stage air bag burst simulation, late vehicle restraint system simulation.Simulation can guide the optimization direction of part performance and lock parameters in advance.For minor changes, it is not necessary to test the whole vehicle, but to use simulation to judge the risk size, and then determine whether it is necessary to test.At present, it is the combination of simulation and test to ensure reliable results before reducing the number of tests.
China is one of the countries with the harshest car operation environment, and the "three high" environmental conditions have higher requirements for the car's environmental adaptability.China has made great progress in the research of car experimental technology and environmental adaptability, but it started late and still has a long way to go compared with foreign countries.As car industry rapidly developed, and the technology constantly improve and progress, to carry out the trend of future experiments can be summarized as: the diversity of environment experiment and practical application environment experiment combined with laboratory imitating experiment environment, focus on the global, experimental environment condition is complicated, covering a wider scale, will be a virtual environment simulation experiment on the direction has a broad application prospect.