At the end of 2008, Zhang Xiaozheng, executive vice president of the China Federation of Machinery Industry, once said that although China's automobile industry has made great progress and the international competitiveness of its products has been continuously improved, there are still a large gap between some core technologies and foreign countries. The automatic transmission is one of them. Due to the fact that no real industrialization has yet been achieved, it is in a controlled situation.
Not long ago, China National Heavy Duty Truck launched the first heavy-duty truck HOWO-A7 equipped with the standard AMT (electronically-controlled mechanical automatic transmission), and stated that the AMT model will be mainly promoted in the future. Prior to this, FAW Group's AMT has also been successfully developed. The AMT of many domestic heavy-duty transmission companies has also been tested on the road for a long time, but all have been stuck on the threshold of industrialization. The listing of the first AMT truck seems to mean that domestic heavy trucks have made new breakthroughs in the development of automatic transmissions.
Choice: AMT is a development trend
According to Liu Wei, director of China National Heavy Duty Truck Group Technology Development Center, Sinotruk research and development AMT is not a whim, nor is it hurriedly launched, but after careful consideration. As early as 2005, heavy-duty gas technicians who frequently visited Europe found that 20% to 30% of European road tractors use automatic transmissions (most of which are AMT), and this proportion is also on an upward trend. The heavy-duty people realize that, as people's requirements for driving comfort become higher and higher, automatic transmissions have occupied a considerable proportion in cars. In trucks, automatic transmissions will also be the trend of their drive systems. Europe has already manifested itself and will soon become a focus of development in China. Whoever first mastered the technology of truck automatic transmission will be able to win market opportunities. However, at that time, heavy-duty trucks did not produce their own transmissions, and the cooperation with R&D AMT was inconvenient. Therefore, AMT projects did not formally operate.
At the beginning of 2006, Shouqi and Weichai were formally separated. Heavy truck had to produce its own key assembly. In addition to the engine, the transmission base began to build. Having its own R&D and production base for transmissions, it is possible for Heavy-Duty to independently develop AMT and control AMT projects well. In particular, the China III engine with electronically controlled high pressure common rail system and electronically controlled EGR system was successfully developed and sold in batches, accumulating the technical foundation for the research and development of AMT with the same electronic control technology. Thus, at the end of 2006, Heavy Truck officially launched the AMT project.
In fact, in addition to AMT, automatic transmissions include AT (hydraulic automatic transmission), CVT (continuously variable transmission), and DCT (double clutch automatic transmission). Why does heavy duty steam choose AMT? Liu Wei explained: “The automatic transmissions used in European trucks are basically AMTs, with only a few ATs provided by ZF and Allison. From a technical point of view, the AT structure is more complex and the cost is higher; the CVT is limited by the transmission torque. According to current technology, it is still difficult to apply to trucks; DCT has no problem in terms of technical principles, but it is the latest technology. There is no precedent for DCT trucks in the world; AMT is not only simple in structure; The cost is low, and what is more important is that the existing domestic manual transmission production equipment and technology can be retained and used.†So, comprehensively, AMT is the most reasonable choice for the Chinese truck automatic transmission technology route. From the perspective of current research and development of domestic trucks and heavy-duty transmission companies, AMT is an inevitable choice.
R&D: Stones from other hills can attack jade
AMT (Automatic Mechanical Transmission) is an abbreviation of Electronically Controlled Mechanical Automatic Transmission System. In layman's terms, an electronic control system (TCU) is installed on the basis of an ordinary manual transmission, and computers are used instead of people to shift gears. The principle of AMT is relatively simple, but the development process is not easy. It is understood that many domestic companies that research and develop AMT have been testing roads for many years and have not yet formed industrialization. There are two difficulties that they have to overcome. One is the development of electronic control systems and the other is the matching of complete vehicles. Because AMT's control software needs to write all possible road conditions, it is necessary to continuously simulate various road conditions during the development process. To deal with these hundreds of trials, one or two test vehicles is definitely not feasible. Therefore, a large number of test vehicles must be guaranteed to match.
Ni Guixiang, Minister of China National Heavy Duty Truck Enterprise Culture Construction, said: "R & D AMT, China's heavy truck took a road of independent innovation to absorb, absorb, and innovate."
Original innovation takes a long time to accumulate. Heavy trucks may miss this opportunity. Therefore, "Heavy-gas research and development AMT, choose to stand on the shoulders of giants, and joint development with foreign design companies." Liu Wei said, "It is a joint development, heavy truck has a completely independent intellectual property rights, rather than a simple introduction of technology." The foreign partners provide TCU platform for CNHTC. The technical personnel of CNHTC will modify and improve the program according to the road conditions and the use environment in China.
Despite the cooperation with foreign design companies, heavy-duty steam R & D AMT process is still very difficult. Li Fayou, director of the transmission design institute of the Heavy-duty Technical Center responsible for the AMT project, had a much paler hair than two years ago. He said that during the entire R&D process, the foreign team sent only two or three engineers for guidance. Most of the design work was done by more than 10 technicians of CNHTC. In the past two years, they voluntarily worked overtime to find information, simulate various road conditions, and constantly experimented and improved.
Liu Wei pointed out: "The process of joint development with foreign companies is actually a process of mutual learning." The so-called mutual learning, that is, not only the technical personnel of Sinotruck to foreign counterparts to learn technology, foreign partners also learn from heavy gas Some experimental conditions that they had not considered before. For example, China’s trucks are heavily overloaded, and when they do the vehicle timing, they cannot do it in accordance with the approved total quality, but more than double, or even more than double; in addition, the reliability of domestic heavy trucks is not as good as that of European heavy trucks, and they are driven in some poor road conditions. At that time, there may be situations such as flameout, brake failure, etc. This is a key consideration for the match between AMT and the vehicle. In Europe, this is no longer the focus of technical research. "For overseas design companies, the cooperation with Sinotruck to develop AMT can enrich their database of electronic control software, and it will greatly benefit them in developing markets in developing countries like China," said Liu Wei.
View related topics: China heavy truck launches new heavy truck HOWO-A7
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