The success of automobile development depends 80% on design. A good vehicle development project should achieve a balanced design of multiple components, multiple systems and multiple objectives. "

This paper comprehensively and systematically introduces the main contents and processes of vehicle design and product development from the aspects of vehicle structure design, product platform development, overall and main parts involved, vehicle regulation design and vehicle trial production.

01 Vehicle structure design: meet the requirements of the environment and consumers

The structural design of automobile is an important basis for the design work. "The structural design of the whole automobile is mainly to achieve connection, layout, size and function." Wu Lijun said that it mainly includes platform development, overall design, BM management, general layout design, modeling design, power design, chassis design, electronic and electrical design, body design, interior and exterior decoration design, thermal system design, dimensional engineering, regulatory design, trial production design and test verification.

"Structure is the carrier and performance is the performance." Wu Lijun said that in terms of vehicle technology integration, it includes the development process of organically combining various automobile assemblies and components through system matching and adjustment to achieve the overall structural requirements and performance objectives of the automobile. Vehicle integration is divided into structure integration and performance integration. The integrated development of the whole vehicle is a process and method based on the performance target of the whole vehicle, which is decomposed layer by layer from top to bottom, organically combines various systems and assemblies of the vehicle, matches and precisely adjusts the system, and effectively controls and balances the target.

When talking about the structural design and performance design of the whole automobile, Wu Lijun said that, in a broad sense, automobile performance refers to the ability of the automobile to adapt to various use conditions, meet the needs of consumers and social environment. At the same time, it also refers to the synthesis of various performance indicators related to finished vehicle products, and it is the feeling that users can perceive and judge the quality of products.

The balance of vehicle integrated development mainly includes three levels. The first level composition balance is the balance of cost, quality and progress of project management. The design and development process is a dynamic balance relationship; The secondary composition balance, including product design, performance design, modeling design and general layout design, also needs to be balanced; The three-level composition balance includes multiple attributes within the performance design and the design of multiple fields within the product.

In Wu Lijun's view, the whole vehicle product development process is a structured and standardized document system that guides the product development process based on the basic business logic of product development, through the systematic summary of historical vehicle development experience, full consideration of business and capacity development, and in combination with the enterprise's research and development organization management model. The core business logic of product development is basically the same, basically following the five processes of scheme planning, concept development, engineering design, sample vehicle test, and launch.

"Platform development, including planning, platform architecture and system scheme selection, product derivation strategy, and platform component generalization strategy." Wu Lijun introduced that automotive platform development is a systematic thinking and solution for efficient product development summarized by global automotive enterprises after years of practice. It is based on an infrastructure platform architecture, deriving a product development model to meet the needs of different market segments; By designing modules with consistent interface dimensions and different performance parameters, cars with different dimensions and performance styles can be assembled; Meet the needs of market customers to the greatest extent. The wave of platformization that rose around 2000 swept all major automobile enterprises around the world; Platformization has permeated from simple technology development to all aspects of the automobile life cycle.

02 Overall design: combination of market demand and professional technology

"The overall design includes the technical scheme design, technical parameter design, vehicle power and economy simulation design, vehicle technical status design, vehicle development benchmarking analysis, etc." Wu Lijun said that automobile overall design is a bridge and link to effectively combine market demand and professional technology, is the key to transform market language into engineering language, and is the leading specialty in vehicle project development. The overall automotive technology includes not only the professional technical depth of vehicle and platform technical scheme research and development, but also the management breadth of system engineering such as vehicle technical status control. As a highly comprehensive specialty in the whole vehicle development process, the overall automotive technology needs to balance the multi latitude needs of the market and products, the whole vehicle and parts, plans and risks, so as to achieve the final output to meet the market demand, and a platform and a vehicle level design scheme that meet the regulatory and technical requirements.

Benchmarking analysis in vehicle development is also very important. Wu Lijun said that this is an important work in the process of product project development and a tool to avoid problems in advance and build product competitiveness. According to the benchmarking level, it is divided into vehicle and component level benchmarking, including performance, structure, quality, cost, design strategy benchmarking, etc.

In automobile design, human-machine layout is a factor that must be considered. Its goal is to meet the use needs of people, but it is often impossible to meet 100% of the needs due to technical or cost reasons. Therefore, human-machine layout is to select specific human body layout under certain design standards. The Society of Automotive Engineers (SAE) standard is adopted as the design standard of human-machine layout in the global automotive industry.

The layout verification can be divided into virtual verification based on 3D data and physical verification based on model, hybrid vehicle or tooling vehicle according to different verification objects. Among them, the former mainly includes digital electronic sample vehicle (DMU) inspection, software simulation, etc; The main method of the latter is subjective evaluation.

Wu Lijun pointed out that strategic design is to undertake the product definition, and further clarify the design direction from the perspective of the design profession by combining the target user needs, industry trends, competitive environment and other elements. It mainly starts from three aspects: first, user research, automobile styling design needs to be guided by the needs of target users; The second is trend research. Automobile styling design needs to ensure that the mass production and listing of automobiles are in line with the aesthetic trend of future users; The third is the definition of family. The car styling design needs to conform to the family definition of the company as a whole and maintain a stable and unified brand image.

Chassis design: the automobile chassis is used to support and install the automobile engine and its components and assemblies, receive the power of the engine, make the automobile move, and ensure normal driving, steering and braking. Traditional chassis is composed of transmission system, suspension system, steering system and braking system.

In the electronic and electrical design, it is divided into electronic and electrical architecture, network communication and diagnosis, circuit design principle, human-computer interaction, starting and power supply system, harness system, lighting system, intelligent vehicle control system, manipulation and signaling device, intelligent system and other parts according to functions, characteristics and levels.

Automobile body design is an important part of design. The vehicle body is used to carry passengers and goods and is responsible for installing other system parts of the vehicle. It can be divided into load-bearing, non load-bearing and semi load-bearing vehicle bodies according to the load-bearing mode. The body consists of an upper body and a lower body, wherein the upper body includes an upper body and a closing piece, the upper body includes a top cover and a side wall, the closing piece includes an engine compartment cover, a fender, a door, a back door, glass, a sunroof, a fuel filler cap, etc., and the lower body includes an engine compartment, front and rear floor plates, etc.

Automobile regulation design is essential. Wu Lijun said that the development of automobile products is based on laws and regulations before design, and meeting the requirements of laws and regulations is a necessary condition for product development and design. Only when the products meet the requirements of laws and regulations and pass the certification of the national automobile authority can they be qualified for production, sales and registration.

The design of automobile regulations focuses on the Announcement, 3C certification and relevant environmental protection regulations. During the whole life cycle of automobile products, a series of laws and regulations work is carried out to ensure that automobile products can successfully pass the certification of the national automobile authorities and the supervision and inspection of market supervision departments at all levels, including automobile product laws and regulations management, certification and regulatory consistency verification.

03 Trial production of whole vehicle: meet the use requirements of target users

The trial production of the whole vehicle runs through all stages from the start of the project to the end of the project. Wu Lijun said that the characteristics of the trial production of the whole vehicle: it can simplify the production of products on the premise of meeting the verification requirements and taking full account of cost, cycle, process and other factors. Classification of vehicle trial production: in vehicle research and development, the vehicle trial production is divided into sample vehicle trial production, model trial production and sample product trial production according to different deliverables.

The trial production and development process is based on hybrid vehicles and engineering models. The design data is verified by hybrid vehicles and engineering models before freezing, and the design sample vehicles are produced after freezing. The advantage of this mode is that the physical objects are involved in the project development and verification earlier, so that the tests are greatly advanced, the production of hybrid vehicles and engineering models, the scheme adjustment is more flexible, and the time and cost are lower. After the redesign data of the design sample car is frozen, the production can be started, and the mold can be shared with the tooling car, thus reducing the cost of the design sample car production.

The test management process, driven by market user requirements and actual use conditions, decomposes the development objectives of the whole vehicle level by level to the vehicle attribute requirements, system requirements and parts at the initial stage of product development. Through the test verification of parts, systems and finished vehicles, it is finally ensured that the automobile products can be comprehensively and effectively tested and verified before being put into production, meet the use requirements of target users, and improve the product reputation.

Among them, the vehicle road durability test is to simulate the use of target users, and the road conditions, loads, load capacities, vehicle speeds, operating loads, operating frequency, artificial conditions and other loads that may cause vehicle failures are not omitted from the test plan. Based on the use of the target users, a test site test scheme related to the user's use is established to ensure that the products have high durability quality in the market through the vehicle durability test.

Collision test is mainly used to test the passive safety of the whole vehicle, mainly including the test development and verification capability of all global safety standards under various working conditions, such as front impact, side impact, angle impact, offset impact, rear impact, pillar impact, and constant velocity collision. It covers the safety standards of China and Europe.