On August 16th, the 2nd International Symposium on Lightweight Technology for Commercial Vehicles, sponsored by CITIC Microalloy Technology Center and Automotive Lightweight Technology Innovation Strategy Alliance, was held in Beijing. At the meeting, Dongfeng Motor Group Co., Ltd. material technology Chief Engineer Kang Ming gave a speech to discuss the current status and significance of commercial vehicle lightweighting.
Multi-factor boosts commercial vehicle lightweight
In Kang Ming's view, energy conservation, environmental protection, regulations, new energy and customer demand are important driving forces for the development of lightweight technology for commercial vehicles.
As of December 2017, the number of motor vehicles in China has reached 310 million. Among them, the number of vehicles has reached 217 million, an increase of 23.04 million compared with 2016, with a growth rate of 11.85%. Small passenger cars (multiplied passengers) The number of cars and buses is 185 million (170,000 small passenger cars registered in the name of individuals), accounting for 85.3% of the total number of cars; the number of trucks (commercial vehicles) is 22.34 million, accounting for cars. The total amount is 10.7%. According to incomplete statistics, the total fuel consumption of commercial vehicles in China accounts for 55% to 60% of total vehicle fuel consumption. Therefore, reducing the self-weight of commercial vehicles can effectively reduce the total fuel consumption.
The light weight of automobiles is also the need of environmental protection. The discharge of 100 km commercial vehicles is about 3-4 times that of passenger cars. The weight of car weight can reduce emissions by 5%~ 6% by 10%; car weight loss is 100kg, CO2 Reduce emissions by 10g/100km.
At the same time, automobile lightweighting is also a requirement of national standards and regulations. China has promulgated GB30510-2014 "Heavy-duty commercial vehicle fuel consumption limit" regulations and GB 1589-2016 "automobile, trailer and car train profile size, axle load and The quality limit. The regulations strictly stipulate the fuel consumption limit and vehicle weight limit of the vehicle.
At present, the proportion of new energy commercial vehicles is constantly rising. In order to solve the problem of the mileage of new energy vehicles, lightweight technology is an important solution.
For commercial vehicles (loading trucks), for every 1000kg of vehicle weight loss, 100,000 kilometers per year, the user can earn 35,000 yuan to 70,000 yuan. Therefore, car lightweighting is also the need of customers' economic interests.
Commercial vehicle materials still have gaps
The lightweight of commercial vehicles has been paid attention to by the whole industry chain, and has made great progress. However, in terms of materials, there is still a gap with the world's advanced level. Kang Ming said that the technical level of domestic commercial vehicles has been greatly developed, and the level of commercial vehicles. It has also been significantly improved. Advanced high-strength steel, aluminum alloy, magnesium alloy, non-metal composite materials, etc. have been common in domestic commercial vehicles, promoting the lightweight, safety and reliability of commercial vehicles, but currently commercial in China. The application ratio and application maturity of advanced materials of vehicles are relatively low compared with foreign advanced standards.
Taking the body-in-white as an example, most commercial vehicles in China are mainly low-carbon soft steel plates, and a small number of low-alloy high-strength steel plates of 340 MPa or higher are used. High-strength steel plates account for 10% to 15% of the weight of the body. The advanced high-strength steel of the white body of 340MPa or higher for advanced commercial vehicles is 40%~60%, even higher. Not only 510MPa grade, even 590MPa, 700MPa and 980MPa grade advanced ultra-high strength steel are also used.
In terms of chassis, the domestic is mainly 510MPa ~ 590MPa grade girders, a small number of models use 700MPa ~ 800MPa grade girders, even heat-treated frame. Internationally advanced commercial vehicles frame steel strength has reached 700MPa ~ 800MPa level. Some companies have also adopted heat treatment frames of 1200MPa or higher, even aluminum alloy frames. The frame weight is significantly lower than domestic similar products.
In terms of leaf springs, the design of full-loaded leaf springs in China is generally 400MPa~550MPa, which is slightly higher than that of equal-section leaf springs, but lower than the full-load static stress level of internationally renowned commercial vehicle leaf springs from 650MPa to 750MPa.
At present, the materials used in domestic high-power engine cylinder heads are: HT250, HT280, HT300, RT350, RT450, etc. The performance of these materials is comparable to that of developed countries, which can fully meet the operational needs of commercial vehicles.
Kang Ming said that around the actual situation of Dongfeng series commercial vehicles, Dongfeng Motor has formulated lightweight technology and technical routes, organized product design, material technology and other technologies from 2015 on the premise of ensuring vehicle reliability, safety and durability. The personnel vigorously carried out the lightweight improvement activities, and achieved gratifying results and won the recognition of the users. According to reports, on June 14, 2018, Dongfeng Tianlong 2018 light win version TH37 was listed. Through material optimization and structural optimization, the light win version TH37 weight Lower 390Kg, the lowest is only 7.86 tons.
For the trend of lightweight futures for commercial vehicles, Kang Ming said that materials and processes are one of the important ways to reduce the weight of automobiles. The integrated application of multiple materials is the development direction of automotive materials. Meet the lightweight-cost-user-required synergistic development, new Materials, new processes and new technologies are the driving force for development. In the future, attention should be paid to coating materials and process technology, low-cost composite materials, monolithic molding technology, foam metal, joining technology and recycling technology.